étu.

deabfi
.1 I ix.
. . :sn

.. . ‘ ‘ “.1“
“in .WfifixfikxtflnEKE

a». 5.35 n... . a .ww.

4.8». ”31%.”?

.it- ..
3m: nan“:
13. .r
:3 n
.i .
..
3%.”:

:34. l:
.511.
.11‘

u~ .o. ,
f 7’ ‘-.rf
_ .i:

3?...
.s

:6 5.“...

 

wwflsmw Lu. ... v v
. 1E: . .W.»uun...~tn. {h

«3%. q :

.5... 1.?

 

' 1 .u
1h.“

f
i

wensn'v LIBRARIES

ll ll 0\lllll

 

 

 

 

 

llllllllllllllllllll ill

.‘I

This is to certify that the
thesis entitled

BACTERIA: FRI- OR FOR?
A BIOLOGY UNIT

presented by

Michelle Marie Curlew

has been accepted towards fulfillment
of the requirements for

 

 

Masters degree in Biological Science

Major p fessor

Date AID/‘1 / .6} / ?fé

0-7 639 MS U is an Aflirmative Action/Equal Opportunity Institution

 

—;

“3W!
Micmgan State
l_ University

 

 

PLACE N RETURN BOX to remove We checkout from your record.
To AVOID FINES return on or More dete due.

———l::J
lmr-q
. Cm

II I I

F—l—j
——l l l
‘ l l l

MSU le An Nflrmetlve ActlorVEquel Opportunlty lnetltmlon
m

     
  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ulna-9.1

BACTERIA: FRIEND OR FOE?
A BIOLOGY UNIT

By
Michelle Marie Corlew

A Thesis

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Division of Science Education

1996

ABSTRACT

BACTERIA: FRIEND OR FOE?
A BIOLOGY UNIT

By
Michelle Marie Corlew

Do high school students enrolled in a first year biology course View bacteria as
friend or foe, and will student attitudes change as a result of a unit examining the many
roles of bacteria and the interactions between humans and bacteria? An attitudinal survey
was administered to two biology classes prior to and at the conclusion of a unit devoted to
bacteria. In this thesis, the attitudinal survey is analyzed and the details of the unit outlined.
Analysis of the attitudinal survey indicate perceptions of bacteria as both friend and foe
prior to the unit, but following the five weeks of study attitudes revealed student

perceptions of bacteria as powerful, exciting, and important.

This thesis is dedicated to the memory of
Morgan Bennett Corlew, beloved grandfather
who passed away during the course of my studies.

iii

Acknowledgements

As with any project, this thesis would not be complete without the help of many
friends and colleagues. I would like to gratefully acknowledge the following people for
their special contributions to this thesis. 4

First of all, my thanks to my biology colleagues at Waubonsie Valley High School
for their willingness to try something new, especially Elaine Modine and Julie Callan for
their support and infinite capacity for listening. I would like to thank my other colleagues
in the science department, especially Carolyn Gloeckle, whose continuing encouragement
and help have made it possible for me to focus my energies on this area. A huge thanks to
science coordinator Dr. Sheryl] Renken for her help in analyzing the data and invaluable
support as we strive to become better teachers.

I want to thank Drs. Howard Hagerman, Marty Hetherington, Clarence Suelter,
and Merle Heidemann for their guidance and encouragement, and for structuring an
outstanding graduate experience at Michigan State University that allows teachers to
explore the field of biology and apply what they have learned in the classroom.

Finally, I would like to thank my parents, Phil and Louise Corlew, and my
grandparents Mary and Morgan Corlew, who taught me to value education, encouraged
and supported me in my educational wanderings, and never discouraged me from taking

the long way home.

TABLE OF CONTENTS

LIST OF TABLES .................................................................................. vii

LIST OF FIGURES ............................................................................... viii

CHAPTER 1 .

INTRODUCTION .................................................................................... 1
Introduction ................................................................................... 1
Literature Review ............................................................................ 2
Principles Demonstrated in Unit ........................................................... 5
The Bacteria Unit and the Course Curriculum ............................................ 6
Comparison of New and Old Approaches ................................................ 8
Review of Written Materials Used in Unit ................................................ 8
Concepts Presented and Their Relation to Existing Curriculum ........................ 9

CHAPTER2

INSTRUCTION ..................................................................................... 11
Outline of Unit .............................................................................. 11
Audio-Visual Aids .......................................................................... 13
Laboratory Exercises ....................................................................... 13
Additional Exercises ....................................................................... 17
Innovative Methods ........................................................................ 19

CHAPTER3

DID STUDENT ATTITUDES CONCERNING BACTERIA CHANGE? .................. 21
Class Demographics ....................................................................... 21
Construction of Pre- and Post-Survey .................................................. 23
Statistical Analysis of Pre- and Post-Survey ........................................... 28
Subjective Evidence Regarding Effectiveness of Unit ................................. 34

CHAPTER4

DISCUSSION AND CONCLUSION ............................................................ 37
Effective Aspects of Unit .................................................................. 37
Ineffective Aspects of Unit ................................................................ 39
Summary .................................................................................... 42

APPENDIXA

SURVEY RESULTS ............................................................................... 44
Table l ....................................................................................... 44
Table 2 ....................................................................................... 45
Table 3 ....................................................................................... 46
Table 4 ....................................................................................... 48

APPENDIX B

SCIENCE OPINION POST-UNIT SURVEY .................................................. 50

APPENDIXC

UNIT OUTLINE AND OBJECTIVES ........................................................... 55
Unit Outline ................................................................................. 55
Objectives ................................................................................... 58

APPENDIXD

LABORATORY EXERCISES .................................................................... 59
Bacteria Cultures from the W.V.H.S. Environment ................................... 59
Disease Detectives: Who's Got the Bug? ............................................... 62
How Can the Growth of Bacteria Be Controlled? ...................................... 66
How Can You Test for Bacteria in Foods? .............................................. 71
Pop Bottle Landfill ......................................................................... 74

APPENDIXE

RESEARCH PROJECTS .......................................................................... 78
Bacterial Disease Research Project ....................................................... 78
Microbial Technology Reports ........................................................... 80

APPENDIXF

CLASSROOM NOTES ............................................................................. 82
Introduction to Bacteria .................................................................... 82
Bacteria and Antibiotics Notes ............................................................ 84
Interesting Facts About Antibiotics ....................................................... 86

APPENDIXG

ANTIBIOTICS AND SOCIETY INTERVIEW ................................................. 9O

APPENDIXH

BACTERIAL DISEASE AND MICROBIAL TECHNOLOGY
RESEARCH PROJECT 1994-95 ........................................................ 92

APPENDIXI

BACTERIA QUIZ .................................................................................. 94

APPENDIXJ

BACTERIA AND VIRUS UNIT OUTLINE 1995 ............................................. 97

BIBLIOGRAPHY ................................................................................... 98

Table
Table
Table
Table

LIST OF TABLES

1 ....................................................................................... 44
2 ....................................................................................... 45
3 ....................................................................................... 46
4 ....................................................................................... 48

vii

LIST OF FIGURES

Figure 1 ...................................................................................... 27
Figure 2 ...................................................................................... 29

viii

CHAPTER 1

Chapter 1

Introduction

Bacteria are among the oldest forms of life on earth; they are enormously
successful. They have been found evaywhere that man has thought to look, including
places where conditions were considered too harsh to support life. From floating bacterial
mats deep in the ocean to sulfur-laden hot springs, from deep in the earth's crust to the gut
tracts of termites and mammals, from Ihennophilus sp. to Esdreridria coli to Rhizobium
sp. , researchers have found ever-increasing numbers of bacterial species as sampling
techniques have become more sophistieated. Bacteria play an integral part in earth's
ecosystem, forging amazingly complex interactions with their environment and with other

organisms.

. How then are relationships between humans and bacteria characterized? "Wash
your hands!” "Don‘t touch - icky bad!" Children are taught from an any age that bacteria
are bad because they cause disease, yet only one percent of all microorganisms are
pathogenic. Wlnt about all the good things that they do? Bacteria also function as nature's
decomposes, aid in digestion, produce and enhance food products, produce numerous
' compounds for industry, and provide tools crucial to genetic study. With this staggering
array of functions, how could bacteria be man's foe?

High school students tend to see issues as black or white, good or bad, right or
wrong. When problems are presented to them, they have a difficult time accepting gray
1

2
areas, searching for facts to push the idea to one extreme or another. Allowing students to

explore and define the gray area of the complex relationships between man and bacteria is

the focus of this thesis.

Are bacteria mankind's friend or foe? Most students have no idea of the vast scope
of organisms that live in worlds they have never seen, and have little understanding of the
important roles bacteria play in their own bodies and in today's society. Prior to the
development of the bacteria unit, this instructor felt that the prevailing attitude of students
would be that bacteria are man's foe. For this thesis, a survey was developed to assess
student attitudes regarding bacteria and to determine if a unit devoted to the study of
bacteria would change student perceptions. Two identical surveys were administered prior
to and at the conclusion of an instructional unit, developed for students in a first year
biology class in order to dispel misconceptions about bacteria, and to develop an
understanding of the complex of roles bacteria play in our world. The student replies were
compiled, the differences between the surveys calculated, and the results analyzed in the
following pages. It was this instructors hope that the instructional unit outlined in this

thesis would change student attitudes regarding bacteria.

LITERATURE REVIEW

"This is a heady time to be a microbe" writes Thomas Canby in his article "Bacteria:
Teaching Old Bugs New Tricks" for Nationalfieggraphig (1993). Students are inundated
with information about bacteria and other microbes, and not only through magazine articles
and news programs. Fictionalized accounts of killer microbes from the movie mm to
the television mini-series of Stephen King's The Stand as well as the Michael Crichton
classic W11 are well known; add to that the best-selling non-fiction book
'1th Hot Zone by Robert Preston and students hear of pathogens capable of wiping out the

3

entire human race, both real and imagined, from a variety of sources. Attempting to
eapitalize on this interest and hopefully counta'act these Hollywood seare tactics are a
variety of articles such as Canby's extolling the virtues of microbes, particularly beneficial
bacteria.

With clever coaching from rnicrobiologists, bacteria and

other "bugs" are being put to work in wondrous ways...Some

microbes serve as factories - making pharmaceutieals, pesticides,

solvents, and plastics. Some help make the snow at your ski

resort. Some separate gold and copper from ores, reducing the

need for chemieals like cyanide. Some rejuvenate tired oil wells.

Some make enzymes for snipping DNA, the first step in genetic

engineering. Some are our fermalters, conveting sugars into

bread, beer, sauerkraut, cheese, yogurt, vinegar, wine. And

some microbes, of course, are age-old enemies, the invisible

messengers of tuberculosis and cholera and other scourges.
But those are relatively few. (Canby, 1993)

Litaature extolling the benefits of bactaia is not a recart trard; in 1981 the journal
mm devoted not just an article bllt an entire issue to industrial microbiology.
"Industrial microbiology is a well-established factor in the world economy, responsible
for a current annual production valued at tens of billions of dollars in the U.S. alone
with a rich history that goes back thousands of years.” (Demain and Solomon, 1981).
Phaff (1981) asserts that 'Tha'e is no ready way to classify microorganisms into the useful
and the nonuseful. All arenseful in the sensethat they helptorecyclethemoleculesofthe
organic worid. In this role they are not merely useful but indispensable.” (1981)

Other articles in the 1981 mm special issue describe the evolving
roles of micromganisms in the production of food and drink, pharmaceutieals, and
industrial chemicals (See Bibliography). Another article discusses applications to
agricultme, which are particularly important as the world population continues to grow
exponertially. "The growing demand for food and other agricultural products is ample

4
practieal justifieation for undertaking the enormous research effort that will be needed to

apply the methods of microbiology to agriculture." (Brill, 1981)

Much literature has also been devoted to the story of antibioties, from the accidental
discovery by Alexander Fleming of Penicillium's effect on staphylococci to the production
of the first penicillin by Howard Florey. The legend of Ethel Florey's ”pee patrol,"
collecting the mine of patients treated with penicillin to extract the excess penicillin from the
urine to be used again, and the discovery of the highly productive Penicilliwn chrysogenum
strain on a moldy eantaloupe brought in by ”Moldy" Mary Hunt of Peoria,~Illinois made for
interesting classroom discussions (See Appendix F for Interesting Facts About
Antibiotics).

Edueators have seen the need to provide a balance of information to students in
regards to pathogenic and beneficial microbes. The imbalance of information to which
students are exposed, heavily favoring pathogars, was noted by Williams and Gillen.

The news media publish many articles about microbes that

eause disease but few articles about microbes tint are useful.
Students have the impression that microbes are harmful and

they far studying them. We eall this attitude microbe phobia,

or a fear of microbes. The teacher must convince impressionable
students that many microorganisms make products that we use

any day and the microbes have an important role in our life.
(Williams and Gillen, 1991)

The disarssion by Williams and Gillen on microbial action in common food moduction led
to an important component of this instructor‘s thesis unit, the student reports on Products
of the Microbial World (Appaldix E).

The accidental dismay of antibioties also provides a crucial vehicle for classroOm
disarssions regarding the importance of basic research. The following quote is illustrative:

5

We need to be reminding our students that basic research is
important. For example, 50 years before antibiotics were
discovered, scieltists had been studying bacteria that eause
disease. They wee not looking for a biochemical treatment
to cure disease. Antibiotics were discoveed by accident. If
basic bacterial research had not been done and specific
microorganisms eausing specific diseases had not been found,
the search for antibiotics would not have made sense. Thee
is a need to show students that basic research is important in
itself. Only with basic research can thee be technology...We
need to communieate to students the beauty of and the need
for pure science. This massing of interesting knowledge for
its own sake then will be rea for technologieal developments
of the future. (Lundgren, 1 1)

Helping students discove some of the unexpected benefits of basic resmrch will lead to

more public support and funding for scientific research in the futtu'e.
PRINCIPLES DEMONSTRATED IN UNIT

In the bacteia unit designed as part of this thesis project, students ergaged in a
laboratory-based exploration of bacteria, focusing on the interactions between man and
microbes. In addition to laboratory activities, lectures, videos, and library research were
also included as part of the unit. The unit was divided into two parts; basic structure and
function, classic laboratory techniques used to study bacteria, action of pathogens on
humans, inteactions between antibiotics and bacteria, and the development of resistant
bacterial strains were studied first. The second portion of the unit focused on the beneficial
aspects of bacteria, including their role as decomposes, importance in food production and
' manufacturing, and the importance and potertial of biorernediatiorr.

Five laboratory activities wee completed by the students during the course of this unit (See
Appendix D for laboratory exercises). In the first lab, "Bacteria of the w.vn.s.
Environhrent", students developed the technique of inoculating plates of nutrient agar with
steile swabs. Studerts traced the source of a simulated communieable disuse spread

6
through the class much as an epidemiologist would at the Center for Disease Control in

Atlanta in work done to complete the second laboratory, 3 group activity entitled "Who's
Got the Bug." For the third laboratory, "Controlling the Growth of Bacteria,” students
inoculated nutriert agar with a live culture, and checked for zones of inhibition around filter

pape discs soaked with samples of antiseptics, disinfectants, and antibiotics.

While the first three laboratory execises dealt with bacteria as foe, the last two dealt
with bacteria as frierd. "Testing for Bacteria in Foods,” thefourth laboratory, introduced
students to an indirect method of detecting bacteria by testing for a product of respiration,
carbon dioxide. The importance of indirect testing cannot be oveemphasized since
isolation of unicellular organisms is so difficult in a classroom setting. The final
laboratory expeierce conducted by the studerts, constructing a "Pop Bottle landfill,"
focused on the role of bacteria as decomposes.

THE BACTERIA UNIT AND THE COURSE CURRICULUM

The bacteria unit was new to the biology curriculum at Waubonsie Valley High
School when this study was conducted, as well as for the K-12 Science curriculum of
Indian Prairie School District. None of the insu'uctors had previously included a unit on
bacteia or microbiology at any level in the district. The biology errriculum at the high
school previously consisted often units of varying length. Most units wee of short
duration, approximately two to three weeks; longe units were broker down into two to
three week sections for testing purposes. These units, composed of core activities and
exams, as well as the sequerce of instruction, have traditionally been determined by a
group of expeienced teachers at the high school. This instructor was expected to follow
the established sequence as a tmche new to the curriculum, although newly developed
activities could be added.

During the 1993-94 school year, when this study was conducted, the units for the
first semeste included Characteistics of Life, Ecology of Wetlands, Cell Structure,
Function, and Transport, Microscopes, and DNA, RNA, and Protein Synthesis which was
concluded during the second semeste. Immediately preceding this study unit were units
on Geietics, Evolution, and Classifieation. Following the bacteria unit, an extensive unit
on Anatomy and Physiology wound up the school yer. The bacteial unit developed
during graduate work at Michigan State Univesity was added to the biology curriculum by

shortening and deleting portions of othe units in the curriculum.

Waubonsie Valley High School was and continues to expeience a strong initiative
to align the curriculum, both to improve instruction and'in orde to implement assessment
requirements, with Illinois' recertly mandated School Improvement Plan. A push for
consistency between sections of the same course and the edict to give a common final exam
for all sections was implemented at the high school during the 1992-93 school year.
Inserting a bacteria unit into this instructor’s classroom meant othe instructors had to add it
to their curriculum as well. Fortunately the othe instructors wee amelable to the idea;
some wee more enthusiastic than othes depending on their comfort level with the topic.
All agreed that this was an area that was relevant to students, was something they would
need to know about late in life, and fit in with the newly developed school philosophy of
students as active participants in learning.

8
COMPARISON OF NEW AND OLD APPROACHES

Beeause microbiology was not previously taught, no comparison between old and
new approaches is possible. Howeve, compared to othe units in the biology curriculum,
the bacteia unit included more laboratory expeielces and activities, more audio-visual
resources, and more student library research than any othe unit. Othe units in the biology
curriculum include one or at most two laboratory execises; some instructors assign library
research on gereic diseases in the advanced genetics unit but no othe studert research had
been conducted in the biology classes. The inclusion of questions requiring the
intepretation of laboratory results on the unit exam was also a new experience for studerts

compared to othe units in the curriculum.
REVIEW OF WRITTEN MATERIALS USED IN UNIT

This unit was prepared primarily during the summe of 1993 at Michigan State's
Kellogg Biologieal Station funded by a grant from the Natioml Science Foundation. It was
modified during the 1993-94 school year and implemerted in March 1994 at Waubonsie
Valley High School in Aurora, Illinois.

Much of this instructional unit was inspired by and drew heavily from a
biotechnology imit on antibiotics prqrared to meet the requirements of the Cellular and
Molecular Biology Workshop held at Michigan State Univesity in East Lansing during the
summe of 1992 by this instructor and he colleagues Greg Deurloo, Tim Hoshal, and
Colleen Pringle. On eampus research yielded a wealth of information on the origin,
production, use, and irnpacts of antibioties on society (Appendix F).

9
Mateial from the Cente for Microbial Ecology presented in 1991 and 1993 at

Kellogg Biological Station for the Environmental and Behavioral Biology Workshop was
also reviewed. This includes mateial from Mimics (Zook, 1989), the laboratory
manual "Environmental Spectrum: Hands on the Environment" (1993), and laboratory
expeiences provided by a variety of instructors A share session between colleagues at
Kellogg Biological Station during the 1993 workshop yielded the activity ”Who's Got the

Bug .

The "Pop Bottle landfill" laboratory was written by Kathy Conleyand Jane Moss,
then revised by Jill Quinley, Steve Lawhead, Eric Buhr, and this instructor during the
summe of 1993 at Kellogg Biological Station. A lecture by J irn Pestka on Food Safety /
Technology given through the Fronties in Science seies during the spring of 1994 at
Michigan State Univesity also contributed mateial for this unit.

CONCEPTS PRESENTED AND THEIR RELATION
TO EXISTING CURRICULUM

The bacteia unit sought to continue building on three concepts that run through the
biology curriculum at Waubonsie Valley High School. Diversity at life was introduced
during the first unit of the year on characteisties of life, and continued through the next
unit examining the ecology of wetlands Diversity continued to be emphasized in units on
cell reproduction, geneties, evolution, and classification. The concept of continuous
change through adaptation also introduced at the beginning of the year and was also
emphasized in the evolution unit taught immediately prior to the bacteia unit. Finally, an
emphasis on personal wellness was expressed through the unit on genetics, and '
continued through anatomy and physiology.

10
The bacteria unit also addresses these three issues. The diversity of life was

demonstrated as the variety of roles bacteia play in nature and industry wee observed.
Change through adaptation was exhibited by the appearance of antibiotic-resistant bacteia]
strains. Finally, personal wellness was addressed through the study of bacteia] diseases
and prevention of food borne illness.

Chapter 2

Instruction

OUTLINE OF UNIT

The bacteria unit was scheduled in this instructor's two biology classes for a five
week period, plus one additional day to complete the Post-Unit Survey, for a total of 26
class periods. The unit was also taught concurrently to other biology sections by other
instructors at Waubonsie Valley High School. The other instructors chose to do a
condensed version of the unit lasting approximately 18 class periods, to allow them to
move on the extensive anatomy and physiology unit taught at the conclusion of the school
year. While all biology students learned about bacteria, an attitudinal survey was

administered only to students in this instructor's classes.

The original plan was to have students spend one week becoming acquainted with
bacterial structure and habitat, as well as with laboratory techniques traditionally used to
study bacteria (See Appendix C for Unit Outline). Following this, two weeks were set
aside for exploration of bacteria as foe. The first topics to be addressed were the scope of
bacterial diseases and modes of transmission. A great deal of emphasis was to be given to
the role of antibiotics in treating bacterial disease in this portion of the unit. The origin of
antibiotics, the mechanisms by which they halt the growth of bacteria, and their impact on
our society were also to be examined. In addition, the causes and concerns arising from
antibiotic resistance were scheduled for discussion. A special lecture discussing the role of

bacteria in food borne illness was prepared, emphasizing the prevention of such outbreaks.

11

12
Working in pairs, students wee to research specific bacteial diseases and to report their

findings to the class.

The final two weeks wee to be spent examining the role of bacteia as man's
frierd. Students wee to explore the importance of bacteia in food production and the
efficiercy of bacteia as decomposers. The role of bacteria in digestion in the gut tracts of
animals, and the vast potertial for biorernediation via bacteial action was to be explored by
studerts in the laboratory as well as in lecture. Finally, pairs of students wee assigned a
microbial product, such as yogurt, researched production methods, and reported their
findings to the class.

Ideally, equal time was to be devoted to the frierd and foe portions of the unit, but
as always happens in public schools, events inteveled and some class peiods wee lost.
State testing took away approximately two class peiods, and an all-school assembly
chipped off nrore time. In addition to the shortened time slot, activities took more class
time than originally scheduled, particularly the researching and presertatiorr of bacteial
disuse reports This resulted in progressing only through Day 22 of the Unit Outline (
Appendix C). The bacteia as flield portion of the unit was shortered and condensed as

this instructor was forced to wrap things up and move on to the next unit.

Although this unit did not follow the original plan exactly, studerts had the
opportunity for many new expeierrces. Students stepped into the central role in the
classroom by peforming five laboratory execises, completing two short research projects
and presenting their results, and inteviewing eldely relatives about medical practices
before the age of antibiotics. Each of these activities will be described in turn.

13
AUDIO-VISUAL AIDS

Three audio-visual aids wee used in this unit. First, laser disc images were used to
allow students to observe the diffeences between gram positive and gram negative of
bacteia. Two othe audio visual aids used wee videos recorded from newsmagazine

shows aired during the spring of 1994.

The first video clip was a short segment (approximately twelve minutes) from
W ertitled "Supebugs." This report, which aired just prior to the start of the
unit in 1994, illustrated the alarming increase in antibiotic resistance, tracing its causes and
illustrating the dangers to the populace.

The second video, ertitled "Is Your Food Safe,” was an installrnert of the news
magazine 9811mm, hosted by Dan Rathe, that also aired during the 1993-94 school year.
This 50 minute video focused on the problem of bacteial contanrination in meat, and had a
variety of meats bought in a supemarket tested at a commecial laboratory for a variety of
pathogers. Both videos wee extremely effective in conveying the concerns and current

problems to the studerts.

LABORATORY EXERCISES

Five laboratory execises, including one group activity, wee utilized to aid studerts
. in developing a dare picture of the microbial world. The first laboratory expeience,
'Bacteia of the W.V.H.S. Environment" (Appendix D) was first gerreated by the
instructor and othes as part of a biotechnology unit on antibioties during the Molecular and
Cellular Biology Workshop at Michigan State Univesity. It was used as an introductory

14
activity to pique student inteest. Students also practiced basic aseptic techniques and had

their first expeience inoculating petri dishes with bacteial samples.

Studelts brainstormed various places in the school to find bacteia to be cultured
prior to conducting the laboratory. Loeales to be sampled ranged from the bathroom,
locke room, school pool, doorknobs, and the principal's phone. Othe student idus
included more pesonal areas such as hair, lips, hands, and coins from their pockets. Afte
listing these ideas on the board and discussing appropriate technique, studerts wee given
pre-poured plates and wee ercouraged to sample whateve they wanted. Studerts used
sterile swabs donated by a loul hospital rathe than using inoculating loops Working two
to a plate, the studerts wee most excited about be'ng allowed to leave the classroom For
two days, studerts recorded both qualitative and quantitative obsevatiorrs of their bacterial
colonies, then exchanged plates and made more obsevations. As a wrap-up, the class
grouped cultures by their color and growth pattens, ther completed post-lab questions.

The second laboratory titled "Who's Got the Bug?" was a group activity rathe than
an experiment (See Appendix D). Studerts used test tubes containing a clear liquid (eithe
distilled wate or a vey dilute sodium hydroxide solution) and, with a straw, exchanged
liquids with three diffeert partnes; the names and order of exchanges wee recorded. The
tubes wee tested by adding a drop of pherolphthale'n indiutor to uch test tube; a pink
result meant the student was "infected” with the simulated disuse. Studerts analyzed the
compiled data to detemine the original 'urries" (students with sodium hydroxide
solution), using the orde of contacts to nrle out affected individuals. A discussion
concening transmission of diseases, as well as social stigrnatization of affected individuals
followed the activity. Finally, students answeed post-activity questions regarding
methodology, transmission and prevention of communicable diseases, and the effect of the
incubation period on tracing the source of the disuse.

15

The third laboratory, "How To Stop the Growth of Bacteria" (see Appendix D),
was the most complex laboratory exercise included in the unit. Students first inoculated
plates with a live culture, either E. coli (gram negative) or Micrococcus luteus ( gram
positive), using appropriate techniques and under direct supervision of the teacher. Sterile
swabs were used because inoculating loops were not available. Students tested various
household antimicrobial agents, with the constraint that they test one antiseptic, one
disinfectant, and one antibiotic (antibiotic discs were donated from the local hospital). Each
set of lab partners was encouraged to test different combinations of products and
organisms. Using distilled water as a control, small discs of filter paper were soaked in the
agent to be tested and carefully placed with forceps on the petri dish divided into quadrants.

Students observed their plates after 24 and 48 hours of incubation.

A large class data table was compiled to compare the effectiveness of the various
agents on the growth of the two different organisms. Students were surprised to learn that
antibiotics were specific to the organism tested. Discovering that the school soap was not
an effective antibacterial agent was a source of concern for students. The importance of a
control was also nicely highlighted when one pair of students failed to correctly inoculate
their plate with the live culture. Working with a live culture, practicing aseptic technique,
distinguishing between disinfectants, antiseptics, and antibiotics, and noting the specificity
of antibiotic - organism interactions were all valuable learning experiences for the students

in this exercise.

The fourth laboratory exercise introduced students to the bacteria as friend concept.
In "How Can You Test for Bacteria in Foods," students tested various food products for
carbon dioxide, the product of respiration in bacteria (as well as many, many other

organisms) using the indicator bromthymol blue (See Appendix D). While there was not

16
an opportunity for student exploration in this execise (all students tested all food

products), students grutly enjoyed the opportunity to work with food in a laboratory
setting (most likely because of the color changes in the bromthymol blue, or pehaps
because class was held before lunch). While reviewing their results, studerts wee
challenged to find common factors in all foods that tested positive. One studert
immediately said "They all taste good!" accurately summing up the concept that bacteial

action may improve the taste and texture of some foods.

The final laboratory execise peformed by the studerts was the construction of a
"Pop Bottle landfill.” More an execise in composting than a landfill, students brought in
food scraps (vegetables only) from home as well as packaging scraps, then constructed a
model ”landfill" using garder soil and reconstructed pop bottles (See Appendix D).
Students took apart their landfills and examined their refuse two days late in orde to
compare decomposition rates of vegetable scraps and packaging scraps. Attempts wee
rrradetoquantify this lab but decomposition occurred sorapidly that aftetwo daysvirtually
none of the food scraps wee musurable. The berefits and use of composting food
scraps at home wee thel discussed in class. Some of the problems that arose during this
execise led to inteesting class discussions. Some studerts had added too much wate to
the soil and their landfills became anaeobic (much to the class' disgust), providing a
valuable and aromatic illustration of the diffeerces between aeobic and anaeobic
decomposition. Anothe instructor used potting soil, which is steile, instud of garden
soil; this nristake stimulated discussion on the berefits of composting and enriching the
microbes in the soil, as well as the importance ofruding labels.

Evaluation of the laboratory experiences is based on the quality of student answes
to questions on lab reports, tuche obsevation of student erthusiasm, studert commerts,
and feedback from collugues regarding obsevations of their own students. Students were

17
enthusiastic and excited while performing their laboratories, were cautious enough to

carefully follow correct procedures, and were eager to show off their results to the
instructor and their peers. Most students took ownership of their petri plates and came into
class the next day demanding to check on their cultures irrrrnediately. Post-lab discussions
were lively with all students participating, drawing conclusions and generating questions.
After these discussions, students completed and turned in lab reports and were able to
answer post-lab questions quickly and completely. They were very quick to make the
appropriate connections between the laboratory experiences, lectures, and relevance to their

world.

Other instructors teaching the unit reported that they had noted similar occurrences
in their classes when teaching this unit, with laboratory exercises generating a high level of
enthusiasm and curiosity. Some of these teacher comments are included in Chapter 3. In
addition, several teachers expressed a desire to modify the curriculum of other units to
include more laboratory experiences, suggesting we use this unit as a model curriculum

unit.

ADDITIONAL EXERCISES

In addition to the above laboratory exercises, students spent time researching both
bacterial diseases and bacterial products in the school library, and presenting reports of
their findings to the class. They also were encouraged to interview elderly relatives or
friends to find what life was like before the development of antibiotics for extra credit

reports.

The first research project was to emphasize the role of bacteria as foe to the

students. Pairs of students chose a disease or group of related diseases from a list prepared

18
by the instructor. Students used the school library, researching causative agents,

symptoms and treatments, methods of prevention, at-risk groups, and interesting historical
facts. They gave oral reports and prepared a visual aid detailing their findings while the
other students took notes on a prepared template (See Appendix E). Students were
required to turn in "fact sheets" rather than written reports, as well as their sources for these

reports.

The second research project, entitled Products of the Microbial World (See
Appendix E), was completed during the "Bacteria as Friend" portion of the unit. Groups
of three to four students were given a grouping of microbial products to research in the
school library. Oral reports were given on the production methods of each product, and
how bacteria are involved in the manufacturing process. Again, students turned in fact

sheets and sources rather than written reports.

The newest technique to be implemented in this unit was the interview (See
Appendix G). Given as an extra credit assignment, students were encouraged to interview
someone over the age of sixty-five to obtain first-hand accounts of what life was like before
antibiotics. After completing a specified list of questions, students generated a question of
their own, then were required to write two paragraphs sumrrring up what they learned from

the interview.

INNOVATIVE METHODS

Although none of these ideas are innovative, to this school and in particular this
biology curriculum these methods and ideas were new. First of all, the inclusion of five

laboratory exercises in one unit was a change for the students. Most units only had one or

19

two laboratory exercises, three at most; some included no laboratory exercises at all, just

paper and pencil activities.

Also before this unit, students were rarely encouraged to choose materials to be
tested in laboratory exercises. They were accustomed to following a strict protocol, and the
chance to choose what to culture or what antimicrobial agent to test was exciting for them.
Also, all student data became important to the class during the analysis. This gave students
ownership of the results; they were not just duplicating what everyone else in class had
done. While it would be wonderful to allow the students to take the next step and design
their own experiments as a follow-up, the ever-expanding amount of material and the ever-
shrinking amount of class time generally prohibits in-depth exploration of topics in this first

year biology survey course.

Surprisingly, this was the first time most biology classes used the media center for
a research project (a few had researched genetic diseases prior to this unit). For the
research on bacterial diseases, most students chose diseases that had some relevance to
their lives, such as the student who picked tuberculosis because his uncle had contracted
the disease. Some students were able to make connections between science and history,
such as those researching the bubonic plague. Most enjoyed the chance to present their
information to the class, and attempted to make their presentations memorable in some

way, like bringing in samples of their microbial products for everyone to taste.

Student-conducted interviews of senior citizens are a technique used in social
studies classes that are just beginning to be brought into science curricula. Not only do
interviews increase student knowledge, but they build bridges between generations. Most
students interviewed relatives, and were amazed at the stories they heard. One third of each

class chose to participate in this activity; nearly every student that completed the assignment

20
reported learning something new about their family history. The personal interview was a

wonderful way to establish a dialogue between the generations, based on science.

CHAPTER 3

Chapter 3

Did the Students Attitudes Concerning Bacteria Change?

CLASS DEMOGRAPHICS

The biology curriculum at Waubonsie Valley High School is taught at the
sophomore (10th grade) level to average students. It is a survey course and is the second
year of a required two year science sequence for graduation. As freshman, these students
enrolled in Introduction to Physical Science; most go on to take Chemistry their junior year.
In addition to those following the traditional sequence, several students had recently moved
into the school district, bringing varied backgrounds. As an alternative to biology,
sophomores can be enrolled in General Science 11, a fundamental life science course, or
Accelerated Chemistry for honors students who have already completed a year of Honors

Biology.

Students live in portions of Naperville and Aurora, far west suburbs of Chicago,
Illinois. The community is affluent, a white collar suburb along an area known as the Hi-
Tech Corridor because of the many research divisions of corporations located along the
main traffic artery, Interstate 88. It is not unusual to have a student in class whose parent is
a Ph.D. researcher at Amoco Research Center or Fermilab National Accelerator Laboratory.
Families move to the area because of the proximity to corporate jobs and the solid
reputation of the schools. So many families move to the area that, at a growth rate of 1500

children per year, Indian Prairie School District is the fastest growing district in Illinois.

21

22
Currently the only high school in the Indian Prairie School District, Waubonsie Valley's

student population ineuses approximately 300 students pe year. In addition to the high
numbe of families moving in, many also move out throughout the school year as parents

are transfered to diffeert job sites.

The community places a high emphasis on success, whethe it is in athletics,
music, drama, or academics. In general, students recognize the value of high achievernert,
particularly grades, primarily in orde to be admitted to the college of their choice
Typiuny it un be difficult to convince the studerts that hard work is necessary to urn
these grades. Most studerts also hold a part-time job by the time they are sixteen, not to
help support their family but to allow them to drive a nice car. They work hard to juggle
their responsibilities between family, academics, extra-curricular activities, and ernployes.
Students and parerts alike have hi glr expectations of the tuches and the school.

Studerts at Waubonsie Valley are sophistiuted in their exposm'e to both cultural
everts and the sciences. Most students have participated in a variety of extra-curricular
audenric experiences, particularly at the elementary level. Family Math Night, Science
Fairs, and the Fine Arts Festival are commonplace everts for studerts in Indian Prairie
School District. In addition, many have toured or atterded programs at Femilab National
Accelerator laboratory, Argonne National Laboratory, or Amoco Research Cente, all
located nur the hordes of the school district. Because of this high level of exposure,

' studerts can sometimes seen jaded, and finding a fresh approach ean be difficult.

In the K-12 science curriculum, no units on bacteia are included and students do
not have the opportunity to develop the laboratory techniques found in the bacteia unit
described in this pape. While they may have discussed some bacteial disuses in the
hulth curriculum, this unit was a new frontie for the studerts in the spring of 1994. In

23
addition, students (and parents) in the district are routinely surveyed on a variety of issues.

The biology studerts also completed a survey on the wetlands unit in addition to the pre-‘

and post-surveys surrounding the bacteria unit during the 1993-94 school year.

In addition to pre- and post-unit surveys, students completed pre- and post-tests as
well as a quiz during the course of the unit. Because this thesis addresses attitudinal
changes, the results of these tests are not included. It is an obvious conclusion that studert
knowledge of bacteia incrusu as a result of this unit; this is eviderced by some of the

items on the pre— and post-unit surveys.

This instructor’s two biology classes at Waubonsie Valley High School wee
surveyed and participated in the bacteia unit during the spring of 1994 (1993—94 school
year), the results of which are reported hee. The first class started with 27 studerts at the
beginning of the unit, and ended with 26 (one studert moved away during the period of
instruction). The second class had 24 students.

CONSTRUCTION OF PRE- AND POST-SURVEY

The attitudinal survey (See Appendix B) was constructed during the fall and winte
of 1993-94 school yur. This instructor included a grut dul of material on attitudes
toward scielce along with attitudes toward bacteia to provide a senblance of disguise due
to the sophistication of the students. A brief analysis of these attitudes towards scielce is
included to check on reliability of the survey. These issues wee not directly addressed in
the bacteria unit although it was hoped that pehaps this unit would improve attitudes

toward science.

24
The Pre-Unit Survey was adnrinistered at the beginning of class prior to beginning

the unit. Students were unaware of the subject of the next unit when taking the Pre-Unit
Survey. In an effort to avoid bias, students were told it was a survey developed by a
colleague in Virginia for her master's thesis, rather than this instructor's thesis. They were
instructed to take their time, consider each answer and circle the choice that best reflected
their opinion, not what they thought someone would want to hear. The mood in the

classroom was very positive that day.

The first portion of the survey was not directly addressed in the bacteria unit. Items
1 through 18 consisted of bipolar adjectives using a seven point scale to define a range of
meaning with respect to the phrase "Science is ..." (Doran, 1980). In order to keep
students from consistently circling the same number, pairs of adjectives considered positive
and negative were alternated so that 7 was sometimes positive and sometimes negative.
The adjectives chosen were drawn in part from Doran's Basic Measurement and Evaluation
of Science Instruction (1980), and a survey written by Sandi Kransi (1991) in a Master's
Thesis for Michigan State University. The results for the first part of the survey are listed

in Table 1 found in Appendix A.

The second portion of the survey, items 19 through 30, also consisted of bipolar
adjectives on a seven point scale used to define a range of meaning but this time with
respect to the phrase "Bacteria are Again, positive and negative terms were alternated.
Items 19 and 30, bacteria are important / unimportant, were made identical to check the
reliability of the survey. Three items that were more factual than attitudinal (items 21, 26,
and 29) were also included. This portion of the survey was the most important to this
instructor. The results for this second part of the survey are listed in Table 2 found in

Appendix A.

25
Scoring for the first two sections of the survey was done by multiplying the point

value of the response by the frequency of the response to obtain a weighted sum, which
when divided by the number of responses gave a weighted mean (see formula below).
Point values were assigned so that 1 was negative and 7 was positive; this required the

reversal in scoring of every other item to provide consistent results.

Weighted Mean = Point Value* x Frequency
Total Number of Responses

* adjusted on some items so that a score of 1 reflected
the most negative adjective, and 7 the most positive

The third section of the survey, items 31 through 50, consisted of statements to be
read by the students, who would then respond via a 6-point scale ranging from strongly
agree to strongly disagree. Statements regarding science in general (items 31, 32, 40, and
50) were interspersed with statements regarding bacteria. Results for this part of the

survey are listed in Table 3 found in Appendix A.

Scoring for this section was also completed through calculation of a weighted
mean. Scores of 1 to 6 were assigned, with 6 representing the answer desired (as defined

by this instructor), whether it was strongly agree or strongly disagree.

The fourth and final portion of the survey, items 51 through 60, consisted of a list
of activities. Students were to choose between attempting a given activity given time and
knowledge (3), not attempting the activity (1), or remain indifferent (2). Results for this

part of the survey are listed in Table 4 found in Appendix A.

26
In addition to the loss of one student in 2nd period, another student chose not to

answer the last portion of the survey. This made the comparison of Pre- and Post-Surveys
particularly difficult, so totaled responses were converted to percentages of the sample so

that trends could be discerned.

The Post-Unit Survey was administered the day after the unit exam. Students were
unhappy with the length of the post-test, and the amount of writing required. In contrast to
the upbeat mood in the classroom the day the Pre-Unit Survey was administered, students
were tired of school, and anxiously awaiting the fetal pig dissection to be done in the next
unit. This instructor believes this had some influence on the results of the survey. When
tabulating the results, on the Post-Unit Survey two students (who sat next to each other)
simply circled the most negative answer possible, and one of these students did not
complete the last page; these surveys were omitted from the results. In addition, the length

of the survey worked against it.

On reflection, a shorter and direct survey of twenty-five questions administered
prior to testing may have been more effective in assessing student attitudes. This instructor
would eliminate the first portion of the survey completely, but keep the entire second
section (items 19 - 30). In addition, some of the statements from the third section would be
retained (items 31, 32, 34, 35, 36, 38, 39, 42, 46, 47, 49, and 50). The final section
would either be eliminated completely or reworked to make it clearer and to force students

to choose rather than giving them the option to be indifferent.

27

Figure 1 Survey Results Items 1 - l8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Science Is
7
.136:
§ :
is; -_ __— __
8. Z
l\ _
a4_ _—— — ~__ _ — - ——
= .
8 _
53— — ~ ~ ~ - ~
0
2
s 2—‘ ~ — ~ . ~
A: .
.20 -
o F — )—
3 “: “ [ i '
O: l i c . _ L
§_§“a°°"E‘E§3°°BEE,§
a 'E.§°°~35:"53m00€3§=0
8.5 2m§g§333 thong
Highest Scoring Adjective
I Pre-Unit Survey
D Post-Unit Survey
Figure 1 A comparison of Pre- and Post- Survey results (weighted means) for the

first portion of the attitudinal survey, Science 15.. Students circled a

number on a scale of l to 7 between pairs of bipolar adjectives to indicate
their response to the phrase "Science Is..." Only the highest scoring term
is included in this figure (See Table 1 in Appendix A for both adjectives).

28
STATISTICAL ANALYSIS OF PRE- AND POST-SURVEY

A comparison of the first part of the Pre- and Post-Unit surveys, Science is
shown in Figure 1 above shows little change in student attitudes. Only seven of the
eighteen items showed a movement greater that 0.2 (on a 7-point scale), with four of these
in a negative direction and three in a positive direction as defined by the instructor.
Following the unit, student attitudes reflected science was slightly more difficult, less
convenient, and more harmful than prior to the instructional unit. As stated previously,
these survey items were not directly addressed by the unit. This could indicate that as
students explore more areas of science, they see the complexity and the amount of hard
work required. The most puzzling result, echoed in later portions of the survey, was the
data indicating students found science more hamrful that before the unit. It was, however,
heartening to this instructor that students attitudes showed they view science as slightly

more important, exciting, and emotional upon the conclusion of this unit.

Analysis of the majority of the items in this first section showed that students
attitudes began and remained in the middle of the scale (3.5 to 4.5) for six items, finding
science a balance between theoretical and practical, imaginative and unimaginative,
subjective and objective, hobby and career, confusing and clear, and strange and familiar.
In addition, students scored several items at the high end of the scale (greater than 5). This
illustrates attitudes in which science is important, changing, necessary, useful, good, and
meaningful. Although the negative movements on items 4, 11, and 12 were somewhat
discouraging, when looking at the overall scores on the scale this instructor feels that

perhaps students have a clear view of what science is about.

29

Figure 2 Survey Results Items 19 - 30

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bacteria Are...
7
2 :
«s .
a .
E 5T 7 T I _
8 :
2. 4; _ _ _ _ _ _
c '1
8 .
2
B
a 2— ~ _ — ~ ~ — ~
.20
Q.)
3
1- .a _ _ _ _ H _
0_ _. L. -l — ._ l— ..
E '5 2 a.) 72' co '5 = '8 8 on H
a is, a Li a E ‘5 E g 5 ’3. 5;
a 2 g E a g m .2 a a
.E g 3.3 m P- 5 E
l-Ll
'0
C
3
O
U-
Highest Scoring Adjective
l Pie-Unit Survey
D Post-Unit Survey
Figure 2 A comparison of Pre- and Post-Survey results (weighted means) for the

second portion of the attitudinal survey, Bacteria Is... Students circled

a number on a scale of l to 7 between pairs of bipolar adjectives to indicate
their response to the phrase "Bacteria are..." Only the highest scoring term
is included in this figure (See Table 1 in Appendix A for both adjectives).

 

30
The second portion of the survey, Bacteria are ..., was the most important to this

instructor. Many changes between the Pre- and Post-Survey occurred in this section. Nine
of the twelve items showed a change greater than 0.2 (on a seven point scale), with eight of
these nine showing a gain. One thing this instructor did not predict was the existing
knowledge level of the students; although bacteria are not addressed anywhere in the K-12
district curriculum, students appeared to grasp the essential idea that bacteria were both

helpful and harmful before beginning the instructional unit.

Two of the items in the survey were factual as opposed to attitudinal; items 21
(rarely found / found everywhere) and 26 (small / large) both scored highly on the Pre-Unit
Survey and showed a gain. Item 23 (harmful / beneficial) showed a decrease. It is
possible that after seeing the variety and seriousness of bacterial diseases, as well as
following increased laboratory safety procedures, student attitudes reflect a heightened fear
of bacteria rather than the healthy respect this instructor intended to engender. This result is
consistent with the decrease seen in items 36 in the next section of the survey and 11 in the

previous section.

Scoring in the middle of the scale (3.5 to 4.5) were items 22, 27, and 28 with the
adjectives dangerous / safe, bad / good, and enemies / friends showing little change (+0.2 )
from the Pre-Survey to the Post-Survey. Scoring on the high end of the scale (greater than
5.0), were items 25 and 29. Item 29, unchanging / changing, showed little change (+0.2),

while item 25, weak / powerful, showed more change, (+0.5) towards powerful.

The largest increases (0.7 to 0.8 on the seven point scale) occurred in identical
items 19 and 30 (unimportant / important) and items 20 (useless / useful) and 24
(dull / exciting), as student attitudes indicate a perception of bacteria as more useful,

exciting, and important than before the unit. Items 19/30 and 20 (useful and important)

3 I
scored at the high end of the scale, while item 24 (exciting) was in the rrriddle. It is

interesting to note that although the weighted means for identical items 19 and 30 are
different (5.8 versus 5.6 during the Post-Unit Survey), the amount of change from the Pre-

to Post-Survey is the same (+0.6), illustrating the reliability of the data.

The third portion of the survey had students agree or disagree on a six-point scale
with a variety of statements (See Table 3 in Appendix A). Four of these statements (31,
32, 40, and 50) concerned science in general. There was no change in items 31 and 32 as
students mildly disagreed with statements that they "would like a career working as a
scientist," and that "science could be left to the experts." A slight decrease (-0.2) was
calculated for items 40 and 50, but students still disagreed with the statement "The
knowledge of science is final and does not change," and agreed with the statement
"Careers in science are interesting and rewarding". One thing worth noting is dichotomy in
the students attitudes, in which they believe careers in science are interesting and

rewarding, but show little interest in a career in science for themselves.

Little or no change (0 to 0.2) was seen in items 33, 36, 41, 42, 44, 45, 46, 47, 48,
and 49. Both before and after the unit, students mildly agreed that it is important to classify
and identify the functions of bacteria, bacteria are useful tools for studying genetics, and
that the government should fund the study of harmful and beneficial types of bacteria.
Students agreed that bacteria occupy an important niche in the environment, and that
without bacteria we would not be alive. In addition, students mildly disagreed with
reducing and eliminating bacteria from earth, that they do not need to know about bacteria
and that it is difficult to find bacteria in a clean house. They disagreed with the statement

"Bacteria are so small it is not important to study them."

32
More change (0.3 to 0.4) was seen in items 36, 37, and 39, with all movement in

the desired direction as defined by the instructor. Following the unit, more students agreed
that precautions such as washing hands were important than before. This can again be tied
to the strong emphasis on safety in the laboratory, where students washed down counters
with a bleach solution before and after each activity. More students disagreed with the
statement "It is unsafe to study bacteria." This indicates to the instructor that students have
internalized the idea that bacteria are found everywhere. While overall students mildly
disagreed with "People who study bacteria should be paid a great deal of money," there
was an increase (+0.4) in the number of students that agreed with this statement. This
instructor found these results intriguing, working in an area where so much emphasis is
placed on financial success. It is unclear whether those students whose attitudes changed
upon the conclusion of this unit placed more value on this activity because they view it as
more important, or whether they place more value on it because they believe it requires a

mastery of certain skills and some risk-taking.

A recurring result was the decrease (-0.4) in the number of students disagreeing
with the statement "It is unsafe to study bacteria." This could be the result of raising
student awareness of pathogens in the laboratory and throughout the school, and perhaps
over-emphasizing laboratory safety concerns, and echoes the results of items 11 and 23 in

previous sections of the survey.

Finally, the largest amount of change (0.6 to 0.7 on the six—point scale) seen in the
third section of the survey occurred in items 38 and 43. Students mildly agreed with
"Bacteria are useful in manufacturing;" this statement is more factual than attitudinal. By
far the largest change between the two surveys had students disagreeing with the statement

"Without bacteria we would lead happy and healthy lives " (item 38). This hopefully

33
reflects student thoughts that bacteria are an integral part of life, and indicates that the unit

was successful in raising student awareness.

The final portion of the survey addressed a list of laboratory-based activities which
related to bacteria. Students could choose to theoretically perform these activities, not to
perform these activities, or remain indifferent. Some of the students (about 10) were
unfamiliar with the meaning of indifferent, and were confused by this section and asked for
clarification. In addition, in this section it was very difficult to establish a comparison
between Pre- and Post-Survey attitudes; to account for the changing sample size (52 vs.
48) results were converted to percentages as previously stated. However, the percent
changes from Pre- to Post-Survey are not balanced. For example, item 52 recorded
changes of -2%, -5%, and +10% in the three categories; somewhere in the changing
sample size 3% is lost. Rather than a strict comparison of percentages, this instructor
looked for overall trends in the computed differences for items 51 through 60. See Table 4

in Appendix A for results.

The results of this section were disappointing; more students chose not to do many
of the listed activities or were indifferent to the activities after the unit compared to before
the unit. This was a surprising result after the positive reactions from students. It could be
the result of two things; students had done many of these activities and were ready to move
on to something new, or once they saw the complexity involved in some of the tasks they
lost interest. If this instructor were to administer this survey again, this section would
either be eliminated or changed so that it could be scored in a manner similar to the first two

sections of the survey.

Following the unit, decreases were seen in five of the ten items (51, 54, 55, 58,

and 60) of the final portion of the survey. Fewer students wanted to perform scientific

34

research, design and produce new food products, determine the cause of food borne
illness, inspect restaurants for bacterial contamination, or work in a science-related field
upon completion of the unit. One interesting result is that fewer students were indifferent
about running a pharmaceutical company (item 57); strong movement was shown in both
directions as student were intrigued by or rejected this activity. A large number of students
remained interested in designing new food products (item 54) even though interest levels

dropped.

More students however, were interested in culturing bacteria in a laboratory and
searching for oil-eating bacteria (items 52 and 59) at the conclusion of the unit. This may
be due to the increase in comfort level culturing bacteria, and high levels of interest in the

environment.

SUBJECTIVE EVIDENCE REGARDING EFFECTIVENESS OF UNIT

Much that goes on in the classroom cannot be easily quantified. A great deal of
informal discussion took place during the bacteria unit. Students were eager to share
personal anecdotes, and generated many questions as connections were made between
subject matter and their own lives. In fact, one of the reasons some planned activities were
eliminated by this instructor was the number of student questions; it was difficult to move

quickly through lectures and post-lab discussions.

The interest level in the class and the enthusiasm displayed by the students in this
instructors classroom, particularly before spring break, was very high; as high as the
genetics unit (the most popular unit of the year) earlier the same quarter. Students were
very excited to be working with so many laboratory exercises, although wary of working

with live organisms. In addition, colleagues teaching other sections of biology reported

35
high interest levels and satisfactory experiences with the laboratory exercises, both from

themselves and their students. The only problem reported was that the unit was too long;
since this instructor spent five to seven days more on the unit than other instructors she

echoes that criticism.

Other instructors at Waubonsie Valley High School that taught the bacteria unit
were surveyed in regards to their experiences teaching the bacteria unit. They were asked
to comment on laboratory exercises, videos, and for any general comments. The following
comments were made regarding the "Bacteria of W.V.H.S Environment" laboratory
exercise:

"Cool!"
"They especially liked this lab...they were amazed at how much bacteria
was all around them."

"Fun to do and to see the results - can surprise the students!"
"Students really enjoy!"

Indicating student enthusiasm was high in other classrooms, one instructor noted
that after the students performed "Who's Got the Bug" that "students liked this so much,

they wanted to do it twice."

Instructors were most excited about the opportunities for student exploration and
class discussion following the laboratory "Controlling the Growth of Bacteria." They made

these comments:

"Good lab."

"Neat - understood throat cultures much better after this lab."

"Very effective in addressing how specific some
anti-microbial agents are."

36
One instructor noted about testing for bacteria in food products "The use of foods in

the laboratory was new to the students and made them see a positive side to bacteria,

although it was a messy lab for clean—up."

Reactions to the lab "Pop Bottle Landfill" were mixed:

"Worked out very well - shows bacterial roles as
decomposers nicely."

"Move it to the ecology unit - integrate bacteria."

"A good idea and somewhat worthwhile but takes too
much time...also messy and smells bad - but kids
seem to like it."

"Get rid of it."

Instructors felt that the videos shown in class were excellent and provoked a great

deal of student thought and discussion. Some of the comments were:

"Is Your Food Safe was one of the best videos this year."

"They liked it a lot but it grossed them out."

" [Sup_erbugs] illustrates there are no 'quick fixes' anymore"

"Good thought-provoking videos, but more direction and
activities related to the videos would be helpful."

"Students changed their habits - like washing their hands more
and being more cautious of kitchen pathogens at home...
won't eat a raw hamburger at a restaurant...somc also
turned vegetarian (they claim)."

Finally, instructors made the following comments regarding the unit in general:

"I enjoyed teaching this unit. One major benefit was bacteria
were no longer abstract invisible creatures students
knew nothing about. The labs made concepts more
concrete for the kids and more enjoyable for me to teach."

"One of the more relevant units we teach. Students have changed
their habits."

"Nice unit, but I feet it takes way too long to fit into a year-long
biology curriculum - especially when one would want
to address viruses too."

"An enjoyable unit - the students seem to really like it."

CHAPTER 4

Chapter 4

Discussion and Conclusions

EFFECTIVE ASPECTS OF THE UNIT

Did students change their attitudes towards bacteria? Survey results from 1994
inidcate there was not a great deal of change in attitudes as students already viewed bacteria
as both friend and foe. However, results of the post-unit survey presented in the previous
chapter indicate that after completing this unit, students view bacteria as powerful, exciting,
and important. These results lead this instructor to the conclusion that overall, this
instructional unit effectively raised student interest. Some areas of the unit, however, were

more effective than others based on student and teacher reactions.

All biology instructors agreed that the most effective portions of the bacteria unit
were the laboratory exercises and the videos shown. The" Bacteria of W.V.H.S." was an
exciting beginning to the unit. Students had a chance to explore their ideas, grow
something they found truly disgusting, and move around not just the classroom but the
school to gather samples. It was a wonderful initiation and effectively introduced students

to the microbial world.

"Who's Got the Bug?" accurately portrayed the social stigma that accompanies
communicable diseases; students immediately connected the analogy of the mixing of fluids
in the "Who's Got the Bug" activity as representative of the spread of HIV (Human
Immunodeficiency Virus) in our society. Students loudly and repeatedly claimed they were

"clean" and did not have the disease. When they tested positive, immediate accusations

37

38
were made that someone else had infected them. N 0 one would believe that they were the

source of the epidemic.

"Controlling the Growth of Bacteria" was, in this instructor's opinion, the best
laboratory experience for the students in the unit. Students had a chance to explore the
actions of common household items and pharmaceuticals even though it was occasionally
difficult for the instructor to supervise appropriate techniques. All student data became
important; students could not just check to see if they "did it right." The parallel of having
a culture for strep throat done at the doctor's office (a common experience for most in the

class) reinforced the feeling that they were doing "real science."

The laboratory the students seemed to enjoy the most, "Testing for Bacteria in
Foods", was the one with which they had the most difficult time answering post-lab
questions (See Appendix D for questions). They loved doing the lab itself, and could
accurately discern the presence of bacteria by the color change, but had a difficult time
explaining the concept behind this indirect method of testing. The quality of answers to
these laboratory questions were poor, as well as on a corresponding essay question on the

Bacteria Quiz (See Appendix I for quiz).

The "Pop Bottle Landfill" was very successful for some students, but not for all.
Those students whose landfills remained aerobic were excited about the results, but those
whose landfills became anaerobic due to too much water were not pleased. In addition to
this lab, student and teacher comments were mixed concerning the reports on bacterial
diseases. Some students really enjoyed that portion of the unit and did a terrific job, others
complained of having a difficult time finding materials or getting their partner to do their

fair share of the work. One teacher commented "It was worthwhile" while another said

39
"My students were n_ot attentive to the other presentations. I feel this time should have been

spent on other worthwhile hands—on activities."

Those students that did the personal interview concerning the impact of antibiotics
on society were very positive in their assignment summary, feeling that they had
established new links with elderly relatives. One instructor commented "Students
witnessed some neat conversations with grandparents and learned more than just about
antibiotics. One student said 'I never knew my grandma was such a neat person. We'll

talk again sometime soon.”

The most effective thing about the unit could not have been planned. The increased
attention given by the media to bacteria, antibiotic resistance, and food borne illness in the
weeks immediately prior to and during the unit keenly raised student interest. Sometimes
with students, the only things that are "real" are the things that are reported on television.
Coverage on the evening news and newsmagazines of the illness caused by contaminated
hamburgers at J ack-In-The-Box, contamination of the Milwaukee water supply by
Cryptosporidium species, and news of the resistant "flesh-eating bacteria" served to raise
student awareness more than anything this instructor could do in the classroom. These
news stories could then be used to begin classroom discussions, to illustrate a point, or to

make connections between laboratory exercises and real-world events.

INEFFECTIVE ASPECTS OF THE UNIT

Four things about the bacterial unit were not effective. First, the reports on
"Products of the Microbial World" were difficult for the students and of poor quality as the
class raced to complete the assignment and wrap up the unit. The inability of the students

to quickly and adequately access information in the school library led to a high frustration

40
level. In the following school year, this assignment was reworked and combined with the

reports on bacterial diseases; students research and report on both at the same time. Having
experience with the project, the school librarians organize material in advance and are better

prepared to help students access information quickly.

Some students now take advantage of the Internet to obtain information; the new
modems in the computer lab facilitate use of this additional resource. Instructions for both
reports were clarified and grading criteria included (see Appendix H) to make this a more
successful project for the students. Student comments have been more positive and reports
of higher quality since implementing this change. In addition, students see a better balance

of bacteria as friend and foe, and use less class time to complete the project

Secondly, students were also very hostile about the unit test; the common complaint
was too much essay. Previous tests throughout the year contained essay as well as fill in
the blank, but also contained matching and multiple choice sections. Although this
instructor informed them of the test format, students felt they were not told what to expect
and this raised their frustration level. It was in this atmosphere that they completed the
Post-Unit Survey. Next time, this instructor would administer any survey items be_fgr§

testing to eliminate this problem.

The strong emphasis on additional safety procedures instituted in the laboratory
while working with live cultures led students to develop high levels of anxiety rather that
the attitude of healthy respect the instructors intended to cultivate. This anxiety was
evidenced by the hesitant actions of the students and the questions asked during the
laboratory experiments, and is most likely responsible for the results noted in survey items
11, 23, and 36. While still insisting on the same safety procedures (primarily use of a 10%

bleach solution to wipe down counters before and after laboratory exercises), instructors

41
use a low-key approach and try to help the students establish a comfort zone while working

with live organisms.

The biggest problem with the unit, however, was not one particular activity but the
length of the unit. Most units in the curriculum were two to three weeks in length, with
longer units broken into two to three week segments for testing purposes. While the
students enjoyed almost every activity in this unit, they tired of studying bacteria and
wanted to move to the anatomy and physiology unit. The situation was exacerbated as
other classes moved on but they did not. Students were extremely anxious that they would
not have enough time to complete the fetal pig dissection they had been looking forward to

all year despite the assurances of this instructor.

Several changes to the unit have been made since its implementation in the Spring
of 1994. The unit has been shortened to 15 class periods (See Appendix J for 1995-96
schedule). The amount of lecture material was reduced slightly when a slide presentation
on clinical microbiology was omitted. Instructors are better organized, and some items
completed in class, such as worksheets on the classification of bacteria, are now given as

homework. Small quizzes break up the unit into manageable portions for the students.

Laboratory materials and their distribution are better organized by the department's
laboratory technician and activities can be conducted much more rapidly now that
instructors are familiar with the exercises. The "Pop Bottle Landfill" was moved to the
ecology unit on wetlands by most instructors, where it continues to reinforce the important
role of bacteria as decomposers. Some instructors demonstrate the laboratory "Testing for
Bacteria in Foods" rather than having the entire class perform the exercise. An alternative

activity, observation of bacterial cultures in yogurt, is also performed by some instructors.

42
In the future, the sequencing of the unit will be altered to present the "Bacteria as

friend" portion of the unit first to emphasize this aspect of the unit to the students. This
should help to alleviate some of the negative changes in the student attitudes indicated by
the Post-Unit Surveys (particularly item 23). This instructor also intends to incorporate an
exercise on bacterial transformation to the genetics unit because students now have

experience working with live bacterial cultures.

In addition to bacteria, a short segment (2-3 days) on emerging viruses was added
to the unit in the 1995-96 school year. Bombardment by the media regarding HIV, Ebola,
and other viruses has shown students that this is something they will be dealing with for
years to come. Another outstanding episode of the television show 4§ Hours entitled "In
the Danger Zone" addresses the emergence of lethal viruses from the rainforest and shows

laboratories where they are studied .

Because of its success in the sophomore biology curriculum, in the 1995-96 school
year the bacteria unit was incorporated into the honors biology curriculum. In addition to
completing the same activities as the sophomore biology students, instructors use the
activities as springboards to bring in fermentation, teach respiration and the production of
ATP, and to study population curves. With these changes, the bacterial unit has become an
integral part of the biology curriculum at Waubonsie Valley High School and, this

instructor is pleased to say, a favorite of instructors and students.

SUMMARY

This instructor is very pleased with the bacteria unit incorporated into the biology
curriculum as a result of graduate work completed at Michigan State University. In

addition to providing new experiences for students , the material is immediately relevant to

43

the students' lives. With so much material and so little time in a general biology course,
this instructor and her colleagues feel that teaching topics most likely to be relevant to the

student's future will drive future decisions of which units to keep and which to discard.

The increased amount of hands-on laboratory experiences is an extremely positive
change for the biology curriculum at Waubonsie Valley, and has encouraged this instructor
and others to reach out and try new ideas. Other instructors in the department have
mentioned using this unit as a template for reevaluating other units in the curriculum. This
instructor would have never predicted, back in the Summer of 1992 at the Cellular and
Molecular Biology Workshop held at Michigan State University, that developing a
biotechnology unit on antibiotics would lead to the myriad of changes in the biology

curriculum at Waubonsie Valley High School.

APPENDIX A

Table 1. Survey Results for Items 1 - 18 Science is
mmmnit Amount W
Term Survey Survey of Term
( 1) (52) (49) Change (7)
l. Unimportant 4.9 5.2 +0.3 Important
2 . Theoietical 3 .9 3 .9 0 PracItical
3 . Difficult 3 .5 3 .2 -0.3 Ea/sy
4 . Inconvenient 4.6 4.0 -0.6 Conv7enient
5 . Comlplex 2 .7 2 .4 -0.3 Si1r71ple
6. Unchainging 6.2 6.1 -0.1 Than/ging
7. Unemotional 2.9 3.2 +0.3 Emotlional
8 . Unneclessary 5.8 5 .6 -0.2 Nece7ssary
9. Unimaglginative 4.2 4.2 0 Imaginative
1 0. Subjelctive 3 .9 4 .0 +0. 1 Obje7ctive
1 l. Harinful 5.6 5.1 -O.5 Ustul
12. Furlzzy 4.1 3.4 -0.6 ClZar
l3. Balid 5.1 5.1 0 G070d
l4. D1111 4.0 4.3 +0.3 Exciting
15. Hobby 4.2 4.0 -0.2 CaZeer
16. Stringe 4.0 3 .9 -0.1 Farn/iliar
l7. Meanilngless 5.2 5.4 +0.2 Meaningful
18. Conflusing 3.7 3.5 .02 CIZar
1 7

Table l. The weighted means for items 1 through 18 of the Pre- and Post Attitudinal

Appendix A
SURVEY RESULTS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Surveys for each pair of adjectives are compared, showing the amount of
change on a 7-point scale. Both adjectives and their adjusted values are

included in the table. 52 students responded to the Pre-Unit Survey, and
49 responded to the Post-Unit Survey.

44

Table 2.

19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.

Table 2.

45

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Survey Results for Items 19 - 30 Bacteria Are
Lowest Scoring Pre-Unit Post-Unit Amount Highest Scoring
Term (1) Survey Survey of Term (7)
(52) (49) Change
Unimportant 5 .3 6. 1 +0. 8 Important
1 7
Useless 5.2 5.9 +0.7 Useful
1 7
Rarely Found 6.2 6.7 +0.5 Found Every-
1 J where 7
Dangerous 3 .7 3 .9 +0. 2 Safe
1 7
Harmful 4.2 3.8 -0.4 Beneficial
1 7
Dull 3.2 4.0 +0.8 Exciting
l 7
Weak 4.5 5.0 +0.5 Powerful
1 7
Large 4.6 4.9 +0.3 Small
1 7
Bad 4.0 4.2 +0.2 Good
1 7
Enemies 3 .8 4 .0 +0. 2 Friends
1 7
Unchanging 5 .2 5.4 +0.2 Changing
1 7
Unimportant 5 .0 5.8 +0.8 Important
1 7

 

 

The weighted means for items 19 through 30 of the Pre- and

Post- Attitudinal Surveys for each pair of adjectives are compared,
showing the amount of change on a 7-point scale. Both adjectives

and their adjusted values are included in the table. 52 students responded
to the Pre-Unit Survey, and 49 responded to the Post-Unit Survey.

46

Table 3. Survey Results for Items 31 - 50 Science is

31.

32.

33.

34.

35.

36.

37.

38.

39.

40.

 

Statement

SA = Strongly Agree
SD = Strongly Disagree

Survey
(52)

Pre-Unit

 

'fiost-Unit
Survey
(49)

Amount

Change

Result

 

I would like to have a career
working as a scientist
SA = 6

2.8

2.8

Mildly
Disagree

 

Most people can leave science to
the experts and do not need to
understand how science works
SD = 6

4.2

4.2

Mildly
Disagree

 

It is important to try to classify and
identify the function of as many

types of bacteria as possible
SA = 6

4.4

4.6

+0.2

 

Bacteria are so small it is not
important to study them
SD = 6

5.2

5.1

 

Without bacteria, we would not be
alive
SA = 6

4.7

4.9

+0.2

 

It is unsafe for anyone to study
bacteria
SD = 6

5.0

4.6

-0.4

 

It is important to observe simple
precautions such as washing your
hands before preparing food

SA = 6

5.4

5.7

+0.3

 

Without bacteria, we would lead
happy and healthy lives
SD = 6

4.0

4.7

+0.7

Disagree

 

People who study bacteria should
be paid a great deal of money
SA = 6

3.1

3.5

+0.4

Mildly
Disagree

 

 

The knowledge of science is final;

it does not change
SD = 6

 

5.2

5.0

 

 

 

Disagree

 

 

47

Table 3 (continued)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

§atement Pre-Unit I'Post-Unit Amount
Survey Survey of Result
SA = Strongly Agree (52) (49) Change
SD = Strongly Disagree
41. Bacteria are important tools in the
study of genetics 4.2 4.4 +0.2 Mildly
SA = 6 Agree
42. Scientists should work to reduce
or possibly eliminate bacteria from 4.1 4.2 +0.1 Mildly
the earth Disagree
SD = 6
43. Bacteria are useful in
manufacturing 3 .8 4 .4 +0.6 Mildly
SA = 6 Agree
44. The government should fund the
study of harmful bacteria 4.2 4.3 +0.1 Mildly
SA = 6 Agree
45. The government should fund the
study of beneficial bacteria 4.4 4.3 -0.1 Mildly
SA=6 Agw
46. The government should fund the
study of bac-teria whether they are 4.4 4.3 -0.1 Mildly
harmful or beneficial Agree
SA = 6
47. It is difficult to find bacteria in a
clean house 4.7 4.9 +0.2 Disagree
SD = 6
48. I do not need to know anything
about bacteria 4 .5 4 .5 0 Disagree
SD = 6
49. Bacteria occupy an important niche
in the environment 4.8 4.9 +0.1 Agree
SA = 6
50. Careers involving science are
interesting and rewarding 4.0 3 .8 -0.2 Agree
SA = 6
Table 3. The weighted means for items 31 through 50 of the Pre- and

Post- Attitudinal Surveys are compared, showing the amount of change
on a 6-point scale. Results of student choices between Strongly Agree
(SA) and Strongly Disagree (SD) are shown in the last column.

52 students responded to the Pre-Unit Survey, and 49 responded to

the Post-Unit Survey.

 

48

 

 

 

 

 

 

 

 

Table 4. Survey Results for Items 51 to 60
Circle: 3 If you would like to attempt such an activity
2 If you are indifferent about attempting such an activity
1 If you would not like to attempt such an activity
Statement 1 1 2— 2 3 3
Pre- Post- Pre- Post- Pre- Post-
Unit Unit Unit Unit Unit Unit
(52) (48) (52) (48) (52) (48)
51. Perform scientific
research Total 15 15 24 23 13 10
% 29 31 46 48 25 21
Diff. +2 +2 -4
5 2. Culture bacteria in a
laboratory Total 21 18 20 16 10 14
% 40 38 38 33 19 29
Diff. -2 -5 +10
53. Test food products
for bacterial Total 17 17 17 17 16 14
contamination % 33 35 33 35 3 1 29
Diff. +2 +2 -2
54. Design and produce
new food products Total 11 15 19 17 21 16
% 21 31 37 35 40 33
Diff. +10 -2 -7
5 5. Determine the cause
of an outbreak of a Total 15 20 23 19 14 9
food-borne illness % 29 42 44 36 27 18
Diff. +13 -8 -8
56. Use bacterial
cultures to study Total 18 18 25 23 8 7
genes % 35 38 48 48 15 16
Diff. +3 -0 +1

 

 

 

 

 

 

 

 

 

Table 4 (continued)

49

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Circle: 3 If you would like to attempt such an activity
2 If you are indifferent about attempting such an activity
1 If you would not like to attempt such an activity
Statement 1 1 2— 2 3 3
Pre- Post- Pre- Post- Pre- Post-
Unit Unit Unit Unit Unit Unit
(52) (48) (52) (48) (52) (48)
57. Run a
pharmaceutical Total 26 27 20 14 5 7
company % 50 56 39 29 10 16
Diff. +6 - 10 +6
58. Inspect restaraunts
for bacterial Total 26 24 14 16 1 1 8
contamination % 50 50 27 33 2 l 17
Diff. 0 +6 -4
59. Search for oil-eating
bacteria Total 27 25 16 1 l 8 10
% 52 52 31 23 15 21
Diff. 0 -8 +6
60. Work in a science-
related field Total 22 21 14 15 15 12
% 42 44 27 31 29 25
Diff. +2 +4 -4
Table 4. The total responses, percent of responses, and calculated percentage

differences for items 31 through 50 of the Pre- and Post- Attitudinal
Surveys are compared. 52 students responded to the Pre-Unit Survey,
and 48 responded to the Post-Unit Survey.

APPENDIX B

Science Opinion Post-Unit Survey

Appendix B

Please circle the number the best represents your opinion. You may only circle one

number.

Science is...

1.

10.
ll.
12.
l3.
14.
15.
l6.
17.
18.

important
theoretical
easy
inconvenient
simple
unchanging
emotional
unnecessary
imaginative
subjective
useful

fuzzy

good

dull

career
strange
meaningful

confusing

NNNNNNNNNNNNNNN

NNN

wwww

UJUJUJUJUJUJUJ

DJ

WWW

50

A-h-hA-bA-hA-bb-bhb-bA-b-h-b

MMMMMMMMMMMMMMMMMM

O\O\O\O\O\O\O\O\O\O\O\O\O\O\O\O\O\O\

\l\)\l\l\l\l\l\l\l\l\l\l\l\l\l\l\l\l

unimportant
practical
difficult
convenient
complex
changing
unemotional
necessary
unimaginative
objective
harmful
clear

bad

exciting
hobby
familiar
meaningless

clear

51

Science Opinion Survey
Page2

Please circle the number the best represents your opinion. You may only circle one
number.

Bacteria are...

.l 9. important 2 3 4 5 6 7 unimportant
20. useless 2 3 4 5 6 7 useful

21. found everywhere 2 3 4 5 6 7 rarely found
22. dangerous 2 3 4 5 6 7 safe

2 3 . beneficial 2 3 4 5 6 7 harmful

24. dull 2 3 4 5 6 7 exciting

2 5 . powerful 2 3 4 5 6 7 weak

26. small 2 3 4 5 6 7 large

27. good 2 3 4 5 6 7 bad

28. enemies 2 3 4 5 6 7 friends

29. changing 2 3 4 5 6 7 unchanging

30. unimportant 2 3 4 5 6 7 important

52

Science Opinion Survey
Page3

For the next portion of the survey, please read each statement and decide if you
strongly agree (SA), agree (A), mildly agree (MA), mildly disagree (MD), disagree
(D), or strongly disagree (SD) and circle your choice below each statement. You may
circle only one choice.

31. I would like to have a career working as a scientist.
SA A MA MD D SD
32. Most people can leave science to the experts and do not need to understand

how science works.

SA A MA MD D SD

33. It is important to try to classify and identify the function of as many types of
bacteria as possible.

SA A MA MD D SD
34. Bacteria are so small it is not important to study them.
SA A MA MD D SD

35. Without bacteria, we would not be alive.

SA A MA MD D SD
36. It is unsafe for anyone to study bacteria.
SA A MA MD D SD
37. It is important to observe simple precautions such as washing your hands

before preparing food.
SA A MA MD D SD
38. Without bacteria, we would leave happy and healthy lives.
SA A MA MD D SD
39. People who study bacteria should be paid a great deal of money.
SA A MA MD D SD
40. The knowledge of science is final; it does not change.

SA A MA MD D SD

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

53

Science Opinion Survey
Page 4
Bacteria are important tools in the study of genetics.
SA A MA MD D SD
Scientists should work to reduce or possibly eliminate bacteria from the earth.

SA A MA MD D SD

Bacteria are useful in manufacturing.

SA A MA MD D SD

The government should fund the study of harmful bacteria.

SA A MA MD D SD

The government should fund the study of beneficial bacteria.

SA A MA MD D SD

The government should fund the study of bacteria whether they are harmful
or beneficial.

SA A MA MD D SD

It is difficult to find bacteria in a clean house.

SA A MA MD D SD

I do not need to know anything about bacteria.

SA A MA MD D SD
Bacteria occupy an important niche in the environment.
SA A MA MD D SD
Careers involving science are interesting and rewarding.

SA A MA MD D SD

54

Science Opinion Survey
Page5

Below is a list of science-related activities. You are to rate these on a scale from 3 to 1
as follows:

3 If you would like to attempt such an activity
2 If you are indifferent about attempting such an activity
1 If you would not like to attempt such an activity.

You are to assume that you have ample time and knowledge to attempt any activity
which may interest you.

51. 3 2 1 Perform scientific research.

52. 3 2 1 Culture bacteria in a laboratory.

5 3. 3 2 1 Test food products for bacterial contamination.

54. 3 2 1 Design and produce new food products.

55. 3 2 1 Determine the cause of an outbreak of a food borne illness.
56. 3 2 1 Use bacterial cultures to study genes.

57. 3 2 1 Run a pharmaceutical company.

58. 3 2 1 Inspect restaurants for bacterial contamination.

59. 3 2 1 Search for oil-eating bacteria.

60. 3 2 1 Work in a science-related field.

Thank you for your time!!

APPENDIX C

Appendix C

Unit Outline and Objectives 1993-94
Bacteria: Friend or Foe?

 

Introduction to Bacteria Group Question Sheet

Demonstrate aseptic technique, discuss its

Lab: Bacteria Cultures From the W.V.H.S.

Observe cultures from Day 2; disposal of plates
Complete Wrap-up Questions from lab with partner

Observation of gram stained slides with Scopecam

Foe: Bacteria Disease and Antibiotics

 

 

Finish notes - (Bacteria and) Antibiotics, Part 11

Library Time - Research bacterial diseases

Continue discussion- Interesting Facts About Antibiotics

WeeLl An Introduction to 133%
Day 1 Pre-Unit Survey and Pretest
Day 2
importance
Demonstrate innoculation of agar plate
Brainstorm areas for sampling bacteria
Environment
Day 3 Observe cultures from Day 2
Go over Intro to Bacteria Group Sheet
Lecture - Introduction to Bacteria
Day 4
Notes - Bacteria (and Antibiotics), Part I
Day 5
or images from laserdisc
Assign bacterial disease reports
Classification of Bacteria Worksheets
Week 2
Day 6 Who's Got the Bug? Activity
Notes - Chain of Infection
Day 7
Introduction of Antibiotic Resistance
Antibiotic Resistance Activity
Review bacterial disease assignment
Day 8
Day 9
Give Extra Credit Assignment - Interview
Antibiotics and Society
Show short Video - "Superbugs"
Day 10 Video: Is Your Food Safe?

55

56

Unit Outline (continued)
Bacteria: Friend or Foe?

 

Week 3 Foe: Mcteria, Disease, and Antibiotics
Day 11 Notes - Foodborne Illness
Prelab - How Can the Growth of Bacteria Be
Controlled?
Day 12 Lab - How Can the Growth of Bacteria Be Controlled?

Article Questions - The End of Antibiotics?

Day 13 Check cultures from Day 11
Give Disease Reports

Day 14 Check cultures from Day 11
Continue Disease Reports

Day 15 Wrap up Lab - Controlling the Growth of Bacteria
Slide Presentation on Clinical Microbiology

Week 4 Friend: Bacteria in Our Food and Our Bgdies

Day 16 Notes - Beneficial Aspects of Bacteria
Products from the Microbial World Assignent -
format for report and poster
Review for Quiz

Day 17 Quiz - Bacteria
Prelab - Testing for Bacteria in Foods
Day 18 Lab -— Testing for Bacteria in Foods
Lab Wrap-up
Day 19 Library Research — Products from the Microbial
World

Day 20 Lab — Popbottle Landfill

57

Unit Outline (continued)
Bacteria: Friend or Foe?

 

 

 

Week 5 Friend: Compos_tir_rg Bioremediation and Technolo
Day 21 Check Popbottle Landfill
Microbial Products Reports
Day 22 Check Popbottle Landfill
Complete Microbial Products Reports
Day 23 Lecture - Microbial Technology
Prelab - Bioremediation with Oil-Degrading Bacteria
Day 24 Lab - Bioremediation with Oil-Degrading Bacteria
Lab - Examination of Termite Gut Tract
Day 25 Post-Test
Week_6 Wrap-up
Day 26 Post-Unit Survey

Check cultures from Day 24
Discussion of Unit

58

Objectives
Bacteria: Friend or Foe?

At the end of this unit, students will:

OO\I O\ LII-RWNH

b-‘\O

y—g
H

12

13
14

15
16

17
18

19
2O
2l

Identify bacteria as the earth's oldest living organisms.

Prepare and observe bacterial cultures using aseptic techniques.

Diagram and identify the structures of a bacterium.

Diagram and identify the 3 basic shapes of bacteria.

Be able to distinguish between gram positive and gram negative bacteria and
discuss the important differences between the two.

Identify where bacteria can be found and describe conditions which are optimal
for bacterial growth.

Discuss the historical and cultural changes resulting from the use of antibiotics.

Describe the mechanisms by which antibiotics control bacterial growth
and reproduction.

Describe techniques for commercial production of antibiotics.

Describe techniques and/or agents which slow or stop the growth of bacteria
(in addition to antibiotics).

Interpret the effects of antibiotics, disinfectants, and antiseptics on bacterial
cultures.

Give examples of antibiotic resistance, factors which lead to its development,
and the resultant effect on bacterial populations.

List and describe several diseases caused by bacteria.

Describe the spread of bacterial diseases and what can be done to prevent
transmission of these diseases.

Model how communicable diseases are spread through a population.

Discuss the role of bacteria in foodbome illnesses and techniques to prevent the
spread of these diseases.

Discuss importance of bacteria in the gut tracts of animals.

Describe the role of bacteria in the decomposition of organic wastes in a landfill
and in nature.

Define and give examples of bioremediation.

List common food items that are bacterial products and how they are produced.

Define and use the following terms:

bacteria gram positive obligate aerobes
colony gram negative obligate anaerobes
pathogen disease facultative

coccus resistance anaerobes

bacillus communicable bioremediation
spirillum virulence vaccination
antibiotic sterilization aseptic technique
toxin disinfectant bactericidal

bacteristatic

APPENDIX D

Appendix D

Laboratory Exercises

Bacterial Cultures from the W.V.H. S. Environment

Objective: Students will collect samples from the local environment, grow
bacterial cultures on a nutrient agar and make observations of these
cultures.

Materials: Pre-poured nutrient agar in petri dish Grease pencil
Wire loop or sterile swab Bunsen burner

Safety: Be sure to follow all microbiology lab safety precautions while
observing your cultures! !

Procedure:

1.

With your teacher, brainstorm collection sites for bacteria. These can be in
the classroom, or if your teacher permits, outside the classroom as well.
Assign a student to collect each sample.

Obtain a petri dish with agar. DO NOT OPEN YOUR PLATE UNTIL YOU
ARE READY TO SMEAR YOUR SAMPLE ONTO THE AGAR!! Use the
marker to draw a line on the bottom of the plate (agar side) splitting the plate
into twos or threes as directed by your teacher. Label the plate with your
initials, the period, the date, and the sampling site.

To sterilize the wire loop, hold it in the hottest part of the Bunsen burner
flame until it glows red, then allow it to cool (about 30 seconds). If you are
using a sterile swab, remove it from the package. Do not let the loop or swab
touch anything except your sample and do not breathe on them!

Obtain your sample by directly wiping the loop or swab onto the collecting
site. Once you have done this, be sure not to breathe on or touch the
loop / swab to any other surface.

Once you have collected your sample, streak your portion of the plate with
the wire loop / swab, opening the plate from the side as your teacher
demonstrates and immediately closing it. Place the plate upside down to
prevent condensation in the incubator. Double check that it is correctly
labeled.

You will make observations of your cultures after 24 and/or 48 hours. You
will need to measure the size of your colony and note this in your data table
along with other observations as color and shape. YOU MUST OBSERVE
ALL SAFETY PRECAUTIONS WHEE MAKING OBSERVATIONS!!

If directed by your teacher, make observations of your classmate’s cultures.
Again, you must observe the proper safety precautions.

When done with the experiment, dispose of your plate as the teacher directs.

59

Date Cultures

Collecting
Site

60

Bacterial Culture Observation Record

Started:

 

 

_Incubation Number of Color of
Time Colonies Colonies

 

—Size (mm) Other
of Colonies Remarks

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

61
Bacteria of the WV Laboratory

Lab Wrap-up Questions

1. What areas did the class decide had a great deal of bacteria?

Why do you suppose this is?

2. Another class tested the drinking fountain. They found the fountain was high
in bacterial growth, but the water proved negative for bacterial growth (no
bacteria grew when the water was tested). Why do you suppose the bacterial
growth was high in the drinking fountain?

3. Would carpeting show more or less bacterial growth than a bare floor? Why?

4. What can be done to keep a house or apartment free of high bacterial growth.
Explain fully at least 5 ways.

5. Why is an incubator used to grow bacteria?

6. How could this experiment be improved to give more accurate results?

62
Disease Detectives: Who’s Got the Bug?

Materials: Small test tube with liquid

Small straw

Directions:

1.

Place the straw into your test tube and place your finger over the end of the
straw, then transfer the contents of that straw (keep your finger over the end
so the liquid will stay in!) to your partner’s test tube. Have your partner
transfer a strawful of their liquid into your test tube. Stir to mix thoroughly.
In the first line of the table under “primary contact”, write the name of your
partner.

Find a different partner. Be sure to write their name under “secondary
contact." Exchange strawfuls of the liquid in your test tubes using the
same technique as in step 1; mix thoroughly with your straw.

Find a third and different partner. Be sure to write their name under “tertiary
contact.” Exchange strawfuls of the liquid in your test tubes using the same
technique and mix thoroughly.

You will now be tested to see if you have been infected with the disease.
Obtain a drop of phenol red or phenophthalein from your teacher. Indicate
in the last column whether your test result was positive (+) or negative (-).

Copy your line down on the overhead transparency of class results, and copy
the rest of the results onto your paper. Dispose of your materials as directed
by your teacher.

Questions:

1.

2.

Which member(s) of the class originally had the disease?

 

 

How did you determine this? Describe the method an epidemiologist might
use to trace an infectious disease.

 

 

 

 

63

How was this disease spread?

 

Name some other ways that diseases are spread.

 

 

How could you have avoided the spread of this class disease?

 

 

 

List some other ways you can avoid the spread of other diseases.

 

 

 

Suppose this disease had a very short incubation period. How would this
affect the spread of the disease?

 

 

 

Suppose this disease had an extremely long incubation period, such as AIDS.
How would this affect the spread of the disease?

 

 

 

64

Disease Detectives: Who’s Got the Bug?

 

Class Results
Name Primary Samdary firtiary
Contact Contact Contact

Test ‘

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

65

Teacher’s Notes
Disease Detectives: Who’s Got the Bug?

Fill the number of test tubes you will need with tap water, about 2/3 full. To two or
three of the test tubes, add a few drops of dilute NaOH. These will be the “diseased”
test tube. Do not use too strong a solution or the students may smell the “disease”!

Phenol red or phenophthalein are both good indicators to use. One drop should do the
trick. If phenolphthalein is used, a pink color is a positive result and clear is a
negative result. If phenol red is used, a purple color is a positive reaction, and a
yellow color is a negative reaction.

Make a transparency of the table for students to write their results on. You might
wish them to design a flow chart to determine their answer.

Do not reuse the straws! Just throw them out. You will need a set of uncontaminated
test tubes for your next class - Don’t reuse!

Try to subtly mark the test tubes with the NaOH - it can be difficult to determine the
exact number of carriers during some trials. '

66
How Can the Growth of Bacteria Be Controlled?

Background: Chemical substances that either kill bacteria or inhibit bacterial growth
are called antimicrobial agents. These chemicals are of three basic types:

antiseptics, chemicals used to inhibit the growth of or kill bacteria on living tissue;
disinfectants, chemicals used to inhibit the growth of or kill bacteria on non-living
tissues; and antibiotics, chemical substances produced by living organisms that
inhibit the growth of bacteria. In this lab, you will test the effectiveness of an
antiseptic, a disinfectant, and an antibiotic in inhibiting the growth of either E. coli or
Micrococcus luteus.

Before working in the microbiology lab, wipe down your lab area with 10%
bleach solution. Allow it to air dry.

Procedure: Part A

1. Obtain a culture of either E. coli or Micrococcus luteus and a sterile nutrient
agar plate.
2. Turn the agar plate over and lay it on the work bench. Using a marking pen,

draw lines dividing the plate into quadrants as shown on Figure 1. Number
the quadrants 1 through 4, placing the numbers near the edges of the dish.
Also write your initials, and the letters EC or ML depending on whether you
use E. coli or Micrococcus luteus.

Corlew 2nd
Figure 1
1 3
2 4
EC

3. Obtain a sterile cotton swab by peeling the wrapper down just far enough to
pull out one swab. Do not lay it down on the table or touch it to any object.

 

 

4. Light your Bunsen burner. Open the culture tube and flame the mouth of the
tube as demonstrated by your teacher.

5. Put the cotton swab into the culture tube and take a small sample of the
bacteria. Flame the mouth of the tube again and replace the cap on the tube.

67

6. Using one hand, open the lid of the petri dish and inoculate the plate by
gently spreading the swab over the surface of the agar. Streak from the top
to the bottom of the plate, then turn the plate 90° and streak from t0p to
bottom again to provide maximum coverage (See Figure 2). Be careful not
to push the cotton swab down into the agar!

Figure 2
7. Place the used cotton swab in the beakers of disinfectant at your lab station.
Part B:
1. Select an antiseptic and a disinfectant to test. You will also need two filter

paper disks and some forceps. Your teacher will also assign you an antibiotic
to test. Record your type of bacteria, antiseptic, disinfectant, and antibiotic
on the data table before going on to the next step.

2. Pass your forceps through the flame of your Bunsen burner. Pick up a filter
paper disk with the forceps and soak it in the antiseptic. Tape off any excess
liquid.

3. Again using one hand, open the inoculated agar plate and position the paper

disk in the center of quadrant 1. With the tip of the forceps, gently press the
disk against the agar until it sticks.

4. Re-flame the forceps. Repeat steps 2 and 3 with the disinfectant, placing
the disk in quadrant 2 this time.

5. Re-flame the forceps again. Obtain the tube of antibiotic disks, and dispense
a disk onto the surface of the agar in quadrant 3. Use the sterile forceps
to gently press the disk onto the surface of the agar.

6. Re-flame the forceps again and repeat steps 2 and 3 with distilled water,
placing the disk in quadrant 4.

7. Your plate should look like the plate in Figure 3. Tape the edges of your
plate closed. Incubate the plate upside down in a 37° C incubator for
48 hours.

68

Figure 3
Antiseptic
1

Antibiotic

 

 

2
Disinfectant

Part C:

l.

Distilled water

Observe the plates after 48 hours of incubation. White or cloudy areas
on the agar indicate bacterial growth. Notice any clear areas called zones
of inhibition surround some of the filter paper disks. A clear area
indicates that bacterial growth was inhibited. You may need to hold the

plate to the light to see the zones more clearly.

 

 

 

 

 

 

 

2. With a millimeter ruler, measure the size of the clear zone surrounding each
disk. Record your measurements in the data table. If no clear zone of
inhibition is present, record the measurement as 0.

3. Report your results on the class data table, then trade plates with a group that
used a different bacterial culture than you did. Observe their results. Are
they the same as yours?

Measurement of
Name of Substance Zone of Inhibition
Bacteria tested
Antiseptic tested
Disinfectant tested
Antibiotic tested
Distilled water

 

 

 

 

69
Controlling the Growth of Bacteria

 

 

 

 

 

Class Data Table
Substance Tested Micrococcus luteus E. coli
Water
Antiseptic #1
Antiseptic #2
Antiseptic #3

 

DisI infectant #1

 

Disinfectant #3

 

‘ DrsI infectant #3

 

Antibiotic #1

 

Antibiotic #2

 

AntiEiotic #3

 

Antibiotic #4

 

 

 

 

 

70

Which antiseptic was most effective in inhibiting the growth of bacteria?

Which disinfectant was most effective in inhibiting the growth of bacteria?

Which antibiotic was most effective in inhibiting the growth of the bacteria?

Were all the antibiotics effective for both types of bacteria? Suggest a reason
for your results.

Write a conclusion for this experiment.

71
How Can You Test For Bacteria in Foods?

Bacteria are living things too small to be seen without a microscope. Bacteria are
said to be microscopic. Often a test can be done to show the presence of microscopic
living things. The test can be done with a chemical indicator.

As its name says, a chemical indicator is a chemical that “indicates” something. One
type of chemical indicator will tell you if carbon dioxide is present. The chemical
turns from blue to yellow or green if carbon dioxide is present.

Respiration in bacteria and other living things produces carbon dioxide. Thus, this
chemical can tell if bacteria or other living things are present in a sample being
treated. Bacteria are used to make many dairy products. The samples you will be
testing in this exercise are different dairy products.

Materials

6 test tubes

6 cork stoppers

test tube rack

wax pencil

2 droppers

3 wooden splints

bromthymol blue solution

dairy products - milk, buttermilk, yogurt, cottage cheese, sour cream

Procedure

1. Label 6 test tubes 1 through 6

2. Fill each test tube with the bromthymol blue solution

3 Use a clean dropper to add one drop of the following to each tube. Do not let
the dairy products go down the slides of the test tubes. Figure 1 shows you

how.
Tube 1 nothing
Tube 2 cottage cheese
Tube 3 buttermilk
4. Using a wooden splint, add an amount about the size of a green pea of the

following to each tube.

Tube 4 plain yogurt
Tube 5 cottage cheese
Tube 6 sour cream
5. Stopper each tube with a cork. Record in Table 1 the color of the tube

contents. Leave the tubes undisturbed. Do not shake.

6. Observe and record the color of tube contents at the bottom of each tube,
both at the end of the class period and the next day.

 

72

 

 

 

 

 

 

Data
Color at Color at Colorl Carbon Bacteria
Tube Contents Start end of day later dioxide present?

class present?

1

2

3

4

5

 

 

 

 

 

 

 

 

 

 

73
Questions

1. Was there a color change in the contents of Tube 1 one day later?

What was the purpose of Tube 1?

 

What name is given to this part of the experiment?

 

 

2. In which tubes was a color change detected one day later?

Which foods were added to these tubes?

 

Do these foods contain bacteria?

 

 

 

 

What is your proof?
3. What is the variable in this experiment?
4. Why are bacteria important to the dairy industry?

 

 

5. Are bacteria in dairy products helpful or harmful?

 

 

74
Popbottle Landfill

Introduction

Solid waste disposal is reaching crisis proportions in many communities. Our throw
away mentality, as well as our increased use of nonbiodegradeable plastics and other
synthetics, has substantially increased our solid waste output. It has been estimated
that the average American produces four to six pounds of garbage per day. This
volume, coupled with the increasing toxicity of the garbage, makes landfilling more
technically challenging than ever before.

Siting of landfills has become a volatile issue and the acronym NIMBY (Not In My
Backyard) reflects the feelings of most US. citizens. Public concern is focused on
aesthetics, odors, groundwater contamination and the spread of diseases. New
methods of disposal are needed to address our current and future waste streams which
are composed of biodegradable and nonbiodegradable materials. Biodegradable
materials can be broken down into simpler substances by bacteria and other
decomposers. A simple compost pile which harnesses the power of bacteria to
"recycle" in the backyard would eliminate much of the waste that often ends up in
landfills. In modern landfills the decomposition process can take decades because of
the lack of oxygen, sunlight, and other factors which often speed up the process of
decomposition. Nonbiodegradable materials are not broken down by biological
organisms and include plastics, aluminum, and many chemicals used in industry and
agriculture.

Scientists and citizens must address the effects on the environment, as well as the
economic impact of handling our wastes. In the investigation, students will study the
results of bacterial decomposition, as well as some of the characteristics of their waste
stream and the problems associated with its disposal. A simulated landfill will be
constructed using garden soil and containing discarded food samples and discarded
packaging samples at room temperature.

Materials

2-liter pop bottle garden soil scissors

tweezers or forceps water permanent marker
distilled water metric ruler newspaper

discarded food samples - vegetables or fruits, etc., but ABSOLUTELY NO MEAT!!!
discarded packaging samples - paper, plastic, aluminum foil, etc.

CAUTIONS
1. Hands should be washed before and after this lab with soap and water.

2. ABSOLUTELY NO FOOD OR DRINK IN THE LAB AT ANY TIME
DURING THE COURSE OF THIS LAB!

3. Lab area should be wiped with a 10% bleach solution before and after
setting up the lab and before and after examining the contents of the landfill.

4. Use a wafting technique for detecting odors.

5. Lab area should be uncluttered with NO books, pens, etc.

75

Special care should be used when cutting the pop bottles. Plastic, as well as
scissors, can cause cuts.

At the completion of the lab, dispose of all materials as directed by your
teacher.

Procedure

1.

10.

11.

Obtain a 2-L plastic pop bottle and remove the label, leaving only a clear
bottle. Use the marker to label the bottle with your name, class period, and
date.

Using scissors, cut the discarded food samples into small pieces,
approximately 3 square centimeters in size, keeping all samples
uniform in size. Repeat this procedure for the pieces of discarded packaging.

With the scissors, cut each pop bottle in half. Using a trowel, fill the base of
the bottle with approximately 6 cm of garden soil.

Record the size, color, texture, odor, and any other important characteristic
features of each sample in your data table. Include a prediction as to how each
sample will look after three days.

Using a pair of tweezers of forceps, place an assortment of food and
packaging samples on the soil in the bottle. Cover the samples completely
with approximately 3 cm of garden soil.

Add enough water to the soil to moisten it. Contents should not be soggy but
should feel like a damp sponge.

Place the top half of the bottle over the bottom half. Patience and repeated
attempts are needed at this point, making sure that the top half is pushed down
far enough for a tight fit.

After 2-3 days, examine the bottle by carefully removing the top layer of soil
into a shallow pan or some newspaper, then remove food and packaging
material with forceps or tweezers. Measurements can be taken but be very
careful not to touch the specimens!

Replace the samples and the soil in the bottle and reseal. Observe the bottles
after a week but DO NOT REOPEN THE BOTTLE. Observations can be
made by rotating the bottle on its side and viewing through the plastic.
Record your observations in the data table.

Follow your teacher's instructions for proper disposal of all materials.

76

Popbottle Landfill Data Table

 

 

Initial After 3 days ARE 1 week
characteristics (size, color, (size, color,
Sample (size, color, texture, odor, texture, odor,
texture, odor, etc.) etc.)

etc.)

 

 

 

 

 

 

 

 

 

 

 

 

 

77

Questions

1. Rank the samples in order of fastest to slowest rates of degradation.
Give an explanation for the different rates of decomposition.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fastest
Slowest

2. Based on your data, classify each sample in this lab as biodegradable or
nonbiodegradable.
Biodegradable
Nonbiodegradable

3. What causes the decomposition (degradation) the samples? Why?

4. Why does condensation collect on the inside of the bottle?

5. Can any of your samples that did not degrade be recycled in the community?
How?

6. How can your reduce the amount of garbage going into the landfill in your

conununfiy?

 

 

APPENDIX E

Appendix E

Research Projects

Bacterial Disease Research Project

You and your partner will be assigned a disease caused by a bacterium. You are to
research that disease and produce a report which you will give to the class. In this
report, you must describe the symptoms of the disease and who is at risk for
contracting the disease, the bacterium responsible for the disease and where it is likely
to be found, and how to prevent the spread of this disease. You may also want to tell
a little of the history of the disease, who is responsible for finding a cure, or anything
else interesting you find in your research. You will be required to present to the class
the information you have found; since your classmates will be taking notes it is
probably best to make an overhead transparency outlining your presentation.
Transparencies and markers are available in the library. In addition, you may wish to
make a small poster to hang in the classroom for a few points extra credit. We will
have one class period in the library, 4/15, to work on this project; you will need to
spend additional time on your report. Your reports will be given on Wednesday,
April 20 in class. If your partner is absent, you will still be required to give your
report (whether or not your materials are present); if both partners are absent you will
be expected to give your report first thing on Thursday April 21. In addition to the 40
points this assignment is worth, you will grade your own partner. Good luck!!

My bacterial disease is:

 

Bacterial Diseases

Pneumonia Tonsillitis and Strep Throat
Scarlet Fever Ear Infections and Rheumatic Fever
Meningitis (bacterial form) Toxic Shock Syndrome
Legionnaire's Disease Diphtheria and Pertussis
Rocky Mountain Spotted Fever Leprosy

and Lyme’s Disease Tuberculosis
Syphilis and Gonorrhea Bubonic, Pneumonic, and
Salmonella and Botulism Septicemic Plagues

Impetigo, Boils, and Pimples

78

79

 

 

 

 

 

 

 

 

 

 

 

 

 

way—mm
«U855...— Bo: 95 037.553.: thoot<
6&2 on g :8 >8: 958 2055 53.583— mESnfimm 925$ 3.585

 

haw—«30 - 3.893— omaoma REESE

 

Bacteria- Man's Friend

Microbial Technology Assignment

Your group will be assigned several foods whose manufacture involves the use of
bacteria, or other processes which benefit from the use of bacteria. The use of
bacteria or other microbes to produce a marketable product is ealled microbial
technology. You are to research those processes assigned to our group, fill in the
accompanying table, and report to the class what you found a ut your products.
Your classmates will fill in their tables from your information.

I want this to be a brief assignment; you should give your report in no more than 5
minutes. You can see this project doesn't require a lot of in-dqrth research; simple
reports will be the best. Your group is responsible for finding the answes for your
products - the class is counting on you! You will have Tuesday in the LMC to find
your information and determine who will talk. You'll have Wednesday to make your
reports; there will not be any otha' time and you need this information for your test on
Friday. Of course, your group is responsible for reporting on Wednesday no matter

who is there.

You will need to turn in a fact sheet as before, listing the information you found and
the sources you use. You should have at least two sources which are not general
reference encyclopedias. Don’t forget to check the computers and the magazines for
current information. If anyone wishes to make a poster illustrating a particular
product of microbial technology to hang in the room for some extra credit, see me

before or after school.
Emma.

Blue cheese

Swiss cheese

Coffee beans
Insecticide - B.t.
(Bacillus thun'ngensis)

Emu

Olives
Pickles
Peas
Sauerkraut
' Detergent

Emmi

Cheddar cheese

Cottage cheese

Nitrogen fixation
(Rhizobium sp. - essential
part of the nitrogen cycle)

Emu

Sourdough bread
Sausages

Yogurt
Insulin

Emmi

Sour cream

Soy sauce
Vinegar
Man-made snow

HINT: The August 1993 mm
' has a HUGE article on
beneficial bacteria!!

8 1
Microbial Technology Reports

 

How bacteria are
Product What it’s made involved in its Miscellaneous
from production Information

 

 

 

 

 

 

 

 

 

 

 

APPENDIX F

Appendix F

Classroom Notes

Introduction to Bacteria

Working together in groups of two or three, answer the following questions based on
what you know about bacteria.

1.

Where in the environment are you likely to find bacteria. List at least 5 spots.

 

 

 

 

a. c.
b. d.
e.

 

How many bacteria are found on a square centimeter of skin?

 

What type of conditions do most bacteria prefer?

 

How many bacteria are in your digestive tract?

 

How many bacteria are passed in a typical bowel movement?

 

What are some ways we can prevent the growth of bacteria?

 

 

Are we born with bacteria?

 

List 5 diseases you think are caused by bacteria.

 

 

 

 

a. c.
b. d.
e.

 

Can people die from a bacterial infection?

 

82

10.

ll.

12.

13.

14.

15.

83

Have you ever taken an antibiotic? What are they used for?

 

 

How many antibiotics are sold in a year?

 

 

What benefits do we get from bacteria?

 

 

Are there any places where it is important to have bacteria?

 

 

Are there any products in our society today that are made with bacteria?

 

 

Are bacteria bad or good?

 

 

 

84
Bacteria and Antibiotics Notes

A typical bacterium (plural = bacteria) has the following cell parts:

(not always present)

 

 

 

 

 

Remember: Bacteria are (have no )

Often grow in

another

, groups of similar cells attached to one

 

Bacteria are classified two ways:

1 . Basic shape

a.

(singular = )
spherical shape, sometimes singular, sometimes pairs or clusters

 

ex: streptococcus (causes strep throat)

(singular = )
rod-like, sometimes singular but often grow in chains

 

 

 

ex: E. coli (found in your intestinal tract; most studied bacterium)
(singular = ) and
spirochetes

spiral or corkscrew shaped, grow as single cells, usually very small

ex: bacteria that causes syphilis

 

 

 

 

 

 

 

85
2 . Gram stain - laboratory technique for staining bacteria to make them easier to
see and for identification purposes
a.
stain absorbed by , appear
cell wall is thicker; usually more sensitive to antibiotics
b.
stain not absorbed, appear
thinner cell wall; often if cell wall lyses (cell membrane ruptures),
bacteria will release toxins (poisons) into host
Antibiotics
anti = biota =
0 over known antibiotics, but < _% have medicinal values

 

antibiotics used commercially

most important groups are the penicillins, cephalosporins, and cephamycins

(antibiotics with the same endings are related, ex: -cillin, -cycline)

most widely manufactured microbial products; over 100,000 tons produced yearly,

gross sales > $5 billion dollars

How do antibiotics stop bacterial infections?

Either kill the bacteria ( ) or inhibit their
growth ( )

Antibiotics use 4 different mechanisms to stop bacterial infections:

1.

Inhibit synthesis of cell wall ( )
cell wall weakens, eventually lyses; not good for
bacteria

 

ex: bacitracin, penicillin G, ampicillin, cephalosporin

Inhibit cell membrane function ( )
changes permeability of cell membrane; cell becomes "leaky"

 

 

 

 

Inhibit synthesis of protein ( )
attaches to bacteria's

ex: erythromycin,tetracycline, streptomycin

Inhibit nucleic acid synthesis

some inhibit RNA synthesis, others incorporatgrinto causing it to )

become defective so that the bacterium is unable to reproduce

example: rifarnpin

There are some antibiotics whose mode of action is not known

86
Interesting Facts About Antibiotics

Effagt 9f Antibiotics an Socigty

Before antibiotics, it was possible to die from a scratch from a rosebush, or a prick
of your finger that became infected.

In the 1930’s, microbial disease was the primary disease in over half the patients
in a hospital.

In 1937 the mortality rate of women in childbirth was 48.9 deaths per 10,000 live
births. In 1957, after antibiotics, the mortality rate was down to 4.1 deaths per 10,000
live births.

During World War I, 15 percent of the battle casualties died from infected wounds.
Once penicillin was abundant during World War H (from D-Day forward) virtually
no casualties died of infection.

Ten years after antibiotics were widely available, the death rate from 8 diseases
influenced by antibiotics was reduced by 50%, saving 80,000 lives.

Within a span of 20 years, life expectancy in the US. was extended 10 years as a
direct result of the introduciton of antibiotics. If all deaths due to cancer were
eliminated, only result a 2 year extension of life expectancy would result.

After the introduction of antibiotics, the following medical procedures became possible:

new and more complex surgical techniques
cardiac surgery

organ transplants

management of severe burns

The use of antibiotics has greatly increased the total number of elderly in our society,
and reduced the child mortality rate.

Pharmaceutical companies became huge conglomerations with research and
development programs that can lead to new, significant, and highly profitable
items of biomedical technology.

Most new pharmaceuticals, including antibiotics, take at least 7 years to make it to the
marketplace where they can be used by the population.

87

Effggts on Physicians

“One day we could not save lives, or hardly any lives; on the very next day we
could do so across a wide spectrum of diseases. This was an awesome aquisition
of power...” John McDermott (see Bibliography)

Before antibiotics, doctors would stay up all night with a sick patient, and often
saw little success.

After antibiotics, they had a drug that could perform “miracles.” Could this have led
them to detach themselves from other and think of themselves as miracle workers?

With a vast plethora of antibiotics that could be used by anybody suddenly available,
patients began demanding and questioning the prescription of different antibiotics.

Early Work with Antibiotics and Miscellangous Facts

Those working with bacteria were at risk of contracting a disease from pathogens.

One case of this was Ronald Hare, who in 1936 pricked his finger with a sliver

of glass infected with streptococci bacteria. His life was saved by an experimental
sulfur drug, Prontosil, he was given by his colleague Leonard Colebrook. Prontosil
is a dye, and Hare turned bright pink when first given the drug. Colebrook also

saved the life of one of his technicians, W. R. Maxted, who was suffering from severe
tonsillitis contracted from his work with strepticocci.

The first man to be treated with purified penicillin was Albert Alexander, a 43-year
old policeman, on Feb. 12, 1941.
-he had an infection that was the result of being scratched by
a rosebush in December
-the infection spread to his face, eyes, scalp, and eventually his
lungs
his eye was removed on Feb. 3rd
-given penicillin on Feb. 12, next day his temperature was normal
and he sat up in bed and ate his meals
—extracted penicillin from his urine and re-injected it
-ran out of penicillin and he died on March 15

Penicillin resistant strains were first observed in 1942 - before widespread use.
The first known death attributed to penicillin was in 1947 - the woman died in minutes.
Antibiotics are used to fight some forms of cancer; actinomycins are used to

inhibit a variety of tumors and fight Hodgkin’s disease, some are

used to treat leukemia.

Antibiotics are vital in the treatment of diseases contracted by AIDS patients .

88

Purification and Production

In 1941 there wasn’t enough penicillin in the US. to treat a single case.

In 1942, there was barely enough penicillin to treat 100 cases.

In 1943, the penicillin needs of our Armed Forces, and those of our allies were all met.

By 1944, penicillin supplies were “unlinrited” - a second miracle in the antibiotic story.

50 years after Fleming’s paper on penicillin appeared, there were 5 grams of penicillin
for every person on the planet .

Ethel Florey, wife of the Nobel Prize winner Dr. Howard Florey, used to go
around on her bike to collect the urine of patients treated with penicillin,

then would take this urine back to Oxford where the penicillin was extracted
from the urine.

All the penicillin manufactured went to the Armed Forces until about 1945.
During World War II, the Army paid from a high of $20 per 100,000 units to
less than 2 cents / 100,000 units - the cost of the packaging was greater than
the cost of the drug.

Purification of penicillin was ongoing at Oxford in England during 1940 - 41,
while Germany was bombing London. Because of this, large scale production
was sought in the United States.

 

The first mass production of penicillin was pioneered in Peoria, Illinois at the
Northern Regional Research Lab of the USDA.

Mass production of penicillin was given top priority by the United States
government (commandeering supplies, equipment) - 2nd only to the
Manhattan Project (atomic bomb).

A Peoria woman - “Moldy Mary” Hunt - brought in a moldy canteloupe which
turned out to have a more productive strain of Penicillium chrysogenum.

In order to speed up mass production of penicillin, a higher yielding strain
was needed. Mutation was accelerated by use of X-rays and UV (ultaviolet)
light.

89

Penigillin and World War II

The development of penicillin played a major role in the Allied victory in World War H:
-Axis powers had access only to sulfur drugs throughout the war
-On the Black Market Germans would obtain large amounts of urine
from patients treated with penicillin, and then try to extract
any penicillin

Mass production of penicillin was given top priority by the United States
government (commandeering supplies, equipment) - 2nd only to the
Manhattan Project (atomic bomb).

Purification of penicillin was ongoing at Oxford in England during 1940 - 41,
while Germany was bombing London. Because of this, large scale production
was sought in the United States.

Although civilians heard about the wonders of penicillin, they were unable to
obtain it until 1945 - all the penicillin manufactured was sent to the Armed Forces.

There was a great fear that the Germans would invade England. If this happened,
Drs. Florey and Chain and their colleagues, working on the purification and

clinical trials of penicillin, would have to destroy their notes on production, cultures,
and any product in the lab. Just in case this happened, Florey and his colleagues
smeared the linings of their coats with spores of the Penicillium fungus.

Effect of Antibiotics on Tuberculosis

Tuberculosis (TB) was the leading cause of death in the United States in 1937.

It was also the greatest cause of death and disability in people aged 15 to 45,

and common in ambitious young people working two jobs or going to school and
working.

A common name for TB was "consumption"

Diagnosis with TB meant:
giving up your job, your schooling, your home, and your family
going to live in a TB Sanitarium, possibly hundreds of miles away
being confined to bed
living as an invalid, never regaining your former strength

TB is still a major problem in Third World countries; 50 - 100 million people are
infected, 3 million die every year. 80% of these people liver where antibiotics
are too expensive to use.

Waksman was awarded the Nobel Prize for the discovery of streptomycin, the
first antibiotic effective against TB, in 1952.

APPENDIX G

Appendix G

Antibiotics and Society Interview
Extra Credit

Interview a person who remembers what life was like before the use of antibiotics

became commonplace. This means they should be at least 65 years old. This interview
should be completed by April 30.

Interviewer:

 

Person Interviewed:

 

Date of Birth:

 

How do you know this person?

 

Date of interview:

 

1. What do you know about antibiotics?

What was medical treatment like before antibiotics were used (before WWII)?

90

91

3. What were hospitals like before WWH?

 

(Write your own question about antibiotics)

5. Is there anything else you'd like to tell me? A personal anecdote about the
family or friends?

Signature of Interviewee:

 

Signature of Interviewer:

 

To complete the assignment:

92

On a separate piece of paper, write two paragraphs telling what you learned while doing
this assignment. It doesn't have to be about antibiotics!

APPENDIX H

Appendix H

Bacterial Disease and Microbial Technology
Research Project 1994-95

You and your partner will be assigned both a disease caused by a bacterium and a
product that is made by or with the help of bacteria (microbial technology). You are
to research both the disease and the product, and produce a report which you will give
to the class. Your classmates will fill in their tables from your information - you’ll be
the teacher! Your report should be about 5 minutes in length - no more. You will
need to turn in a fact sheet which lists the information you found and the sources you
used. You should have at least two sources which are not general reference
encyclopedias. Don’t forget to check the computers and the magazines for current
information!

Your report must meet the following criteria. For the disease, you must describe the
symptoms of the disease, who is at risk for contracting the disease, the bacterium
responsible for the disease and where it is likely to be found, and how to prevent the
spread of this disease. You may also want to tell a little of the history of the disease,
who is responsible for finding a cure, or anything else interesting you find in your
research. For the product, you must discuss how it is made, how bacteria are
involved in its production, and any miscellaneous information you can find.

You will be required to present to the class the information you have found; since
your classmates will be taking notes it is probably best to make an overhead
transparency outlining your presentation. Transparencies and markers are available in
the library ($0.10 per sheet). In addition, you may wish to make a small poster to
hang in the classroom for a few extra credit points. We will have two class period in
the library, and , to work on this project; you will need to spend
additional time on your report.

 

Your reports will be given on in class. If your
partner is absent, you will still be required to give your report (whether or not your
materials are present); if both partners are absent you will be expected to give your
report at the beginning of the next class period. This assignment is worth 50 points;
you will have a chance to grade your own partner. Good luck!!

My bacterial disease is:

 

My bacterial product is:

 

My partner is:

 

Phone #

 

93

94

Microbial Products
Blue cheese Sourdough bread
Swiss cheese Sausages
Coffee beans Yogurt
Insecticide - B.t. Insulin

(Bacillus thuringiageinsis)

Sour cream Olives
Pickles Soy sauce
Peas Vinegar
Sauerkraut Man-made snow
Detergent Cottage cheese
Cheddar cheese

Nitrogen fixation
(Rhizobium - essential part of the nitrogen cycle)

HINT: The August 1993 National Geographic has a HUGE article on beneficial
bacteria!!

Bacterial Diseases

Pneumonia Tonsillitis and Strep Throat
Scarlet Fever Ear Infections and Rheumatic Fever
Meningitis (bacterial form) Toxic Shock Syndrome
Legionnaire's Disease Diphtheria and Pertussis
Rocky Mountain Spotted Fever Leprosy

and Lyme's Disease Tuberculosis
Syphilis and Gonorrhea Bubonic, Pneumonic, and
Salmonella and Botulism Septicemic Plagues

Impetigo, Boils, and Pimples

APPENDIX I

Appendix I

Bacteria Quiz

Sketch a typical bacterial cell and label its parts. Be sure to include the cell
wall, the flagella, the cell membrane, the DNA, the cytoplasm, and the
capsule.

What is a microorganism?

 

 

What three roles do bacteria play in the environment?

a.

 

b.

 

C.

 

Name and sketch the three basic bacterial shapes:

 

 

a. sketch:
b. sketch:
c. sketch:

 

For the following statements, decide whether it describes a bacterium that is
a. gram positive b. gram negative

organism stains a purple color

organism stains a pink color

thin cell wall

thick cell wall

95

96

MATCHING: Some choices will not be used
6. an antimicrobial agent applied
to living tissue
7. organism capable of causing disease
8. organism with no membrane—bound

organelles or nucleus

9. kingdom in which bacteria are placed

10. an antimicrobial agent that is applied
to non-living surfaces

Monera

eukaryote

Animalia

disinfectant

pathogen

antiseptic

prokaryote

Use the following diagram and information to answer the questions below.

 

 

Culture Record #018
Patient: G. Elmen
Physician: M. Corlew

Date: 3/25/94

Throat Culture

A patient comes to Dr. Corlew with a throat infection, which Dr. Corlew samples
with a sterile swab. She spreads the bacteria on the agar in a petri dish and places
four antibiotic discs, A through D, on the plate. After 24 hours, the plate appeared as

above.

11. Which antibiotic do you recommend Dr. Corlew should prescribe for the

patient? Why?

 

 

 

12.

13.

14.

15.

16.

‘97

What is the area free of bacterial growth around the antibiotic called?

 

What two conditions did Dr. Corlew need to provide to grow the bacteria? In
what device did she place the plate? ,

 

 

 

Suppose Dr. Corlew ran some other tests on the bacteria, such as gram
staining, and was able to identify the bacteria causing the infection. She looks
in the PDR to recommend an antibiotic, and she sees that Antibiotic C should
have killed the bacteria. What can she conclude about the bacteria causing this
infection?

 

 

Dr. Corlew has to be cautious when working with potentially pathogenic
bacteria. What is the name of the group of safety precautions she follows?

 

 

List at least 3 safety precautions Dr. Corlew should take while culturing her
patient. List more for extra credit!!

a.

 

b.

 

C.

 

Extra Credit:

APPENDIX J

Day 1

Day 2

Day 3

Day 4

Day 5
Day 6
Day 7

Day 8

Day 9

Day 10

Day 11

Day 12
Day 13
Day 14
Day 15

Appendix J

Bacteria and Virus Unit Outline 1995

Demonstrate aseptic technique, discuss importance
Demonstrate inoculation of agar plate

Brainstorm areas for sampling bacteria

Lab: Bacteria Cultures from the W.V.H.S. Environment

Check cultures from Day 1

Introduction to Bacteria Group Question Sheet
Notes - Bacteria and Antibiotics, Part I
Homework: Classification of Bacteria Worksheets

Check cultures from Day 1
Assign bacterial disease and bacterial products reports
Finish notes

Yogurt Lab - Observation of live cultures; comparison with
prepared slides

Library Research

Video: "Is Your Food Safe?" (48 Hours)

Notes - Bacteria and Antibiotics, Part H (focus on difference
between bacteria and virus)

Prelab - Controlling the Growth of Bacteria

Lab: How Can the Growth of Bacteria Be Controlled?
Discussion: Foodbome Illness

Check plates
Quiz - Classification, Structure / Function
Complete Discussion: Foodbome Illness

Activity: Who's Got the Bug?
Notes - Chain of Infection

Lab: Testing for Bacteria in Foods
Lecture - Beneficial Aspects of Bacteria

Video: "In the Danger Zone" (48 Hours)
Lecture packet on viruses
Student Reports

Test over Bacteria and Virus Unit

98

BIBLIOGRAPHY

BIBLIOGRAPHY

Aharonowitc, Yair and Cohen, Gerald, "The Microbiologieal Production of
Pharmaceutieals," W, Vol. 245 No. 3 September 1981,
pgs. 141- 154.

Canby, Thomas Y., ”Bacteria: Teaching Old Bugs New Tricks”, We
August 1993 pgs. 36-60.

Center for Microbial Ecology, "Environmental Spectrum: Hands on the Environment"
laboratory Manual, Michigan State University, East Lansing, Michigan 1993.

Demain, Arnold L and Solomon, Nadine A, "Industrial Microbiology," Scimtjfic
Amgjean, Vol. 245 No.3 September 1981, pgs. 67-76.

Duran. Rodney L. dew Instruction.
National Science Teachers Association, Washington , D.C., 1980.

Eveleigh,Dou as E., "The Microbiological Production of Industrial Chemicals",
V,o.l 245 No. 3 September 1981, pgs. 155- 178.

Kransi, Sandy, "Evaluation of a Stream Study Unit Used As An Introduction
to High School Biology", Michigan State University, East Lansing,
Michigan 1991.

Phaff, Herman J., "Industrial Microorganisms," Wan," Vol. 245 No.3
September 1981, pgs. 77-89.

Rose, Anthony H., "The Microbiologieal Production of Pharmaceutieals",
W, Vol. 245 No.3 September 1981, pgs. 127- 140.

Williams, Robert P. and Gillen, Alan L., "Microbe Phobia and Kitchen Microbiology,"
WW, Vol. 35 No. lJanuary 1991, pgs. 10-11.

Zook D.. Microoosmos: WW2 MimhiaLSmce.
Kendall Hunt Publishing, Iowa, 1989.

100

GENERAL REFERENCES

Bottcher, Helmuth M. Wonder Drugs - A Histog of Antibiotics, J. B. Lipincott
Company, Philadelphia and New York, 1964.

Brock, Thomas and Madigan, Michael, Biology of Microorganisms, Prentice Hall
Publishing, Englewood Cliffs, New Jersey, 1991

Boyd, Robert R, General Microbiology. Times Mirror Mosby College Publishing,
St. Louis, 1984.

Galdston, Iago M.D., ed., The Impact of Antibiotics on Medicine and Society,
International Universities Press, 1958

Lancini, Giancarlo and Parenti, Francesco, Antibiotics - An Integrated View.
Springer Verlag Publishers, New York, 1982.

Lappe, Marc Ph.D., Germs That Won't Die - Medical Consequences of the Misuse
of Antibiotics, Anchor Press,Garden City, New York, 1982.

Maugino, Richard A., A Laboratogz Manual for Microbiology, J. Weston Walch,
Portland Maine, 1975.

McDermott, Walsh with Rogers, David B, "Social Ramifications of Control of Microbial

Disease," Johns Hopkins Medical Journal, Vol. 151 No. 6, December 1982,
pgs. 302-312.

 

Parascondola, John, A Histogy of Antibiotics: A Symposium, American Institute of
Pharmacy, Madison, Wisconsin, 1980.

Wainwright, Milton, Miracle Cure - The Story of Penicillin and the Golden Age of
Antibiotics, Basil Blackwell, Ltd., 1990.

Welch, Henry Ph.D. and Marti-Ibanez, Felix, The Antibiotic Saga, Medical
Encyclopedia Inc., New York, 1960.

 

HICHIGQN sran UNIV. LIBRRRIES
"HI"I"!W"!HIlllllllllllllllllllllHHlllll”lllllllllll
31293014057593