mrwam muzmw ma mmew 01? Am FUMQR magmas. w smwg gums cm s: F. W? Aw: gums gcsaug (Pam. 35mm Tlm- {saw {“113 DWK‘QQ «21$ M . Sh MECEEGM STRTE U WEESET‘E Keith mexrafz‘é E: Re 1966 THESIS LIBRARY Michigan State University E663?! USE CM THESIS 1. x .I .5‘ IIIFIIIIi I .K w... H x H. V! :err ‘II 2 ABSTRACT NITROGEN UTILIZATION AND PRODUCTION OF ANTITUMOR SUBSTANCES BY SUILLUS LUTEUS (FR.) S.F. GRAY AND SUILLUS ACIDUS (PECK) SINGER by Keith Howard Erke The purpose of this study was to determine the nitrogen requirements of Suillus luteus (Fr.) S.F. Gray and Suillus acidus (Peck) Singer and to investigate the production of antitumor substances produced in vitro by these organisms. Nitrates, ammonium compounds and amino acids were used as nitrogen sources with emphasis on the utilization of the amino acids. The organisms were cultured on a rotary shaker. Both medium A, a modified Czapek's-Dox medium, and a syn- thetic medium were employed. For the nutritional study the various nitrogen sources were added to the basal syn- thetic medium. The growth response was measured by de- termining dry weights of the mycelium at 10 and 15 day Keith Howard Erke periods. The antitumor activity was determined by testing extracts in female Swiss albino mice inoculated with Sarcoma 180 tumors. Growth curves were established for g. luteus and g, acidus growing on medium A. Increasing the shaker speed re- sulted in a reduction of the lag phase of the growth cycle and shortened the length of time to the stationary phase. Growth curves were also established for both organisms when grown in the synthetic medium. Nitrates were not utilized, except limited growth of g, luteus occurred with potassium nitrate. The ammonium compounds supported a fair amount of growth by each organ- ism. The following amino acids were the best nitrogen sources in the synthetic medium: L—alanine, DL—alanine. L—glutamic acid and L—aSpartic acid for the best growth of 'g. luteus, and L-arginine and L-lysine for s. acidus. Antitumor substances were produced by both organisms when grown in medium A. Suillus luteus grown in medium A for 15 days showed 70% inhibition of tumor growth. Anti— tumor substances were likewise produced by both organisms when grown in the synthetic medium containing the amino acids which supported better growth. The best antitumor activity 2 Keith Howard Erke for both organisms occurred in extracts of 15 day old cul- tures. None of the extracts tested retarded the growth of the mice during the test period. NITROGEN UTILIZATION AND PRODUCTION OF ANTITUMOR SUBSTANCES BY SUILLUS LUTEUS (FR.) S.F. GRAY AND SUILLUS ACIDUS (PECK) SINGER BY Keith Howard Erke A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of V MASTER OF SCIENCE Department of Botany and Plant Pathology 1966 To my family ACKNOWLEDGEMENTS The writer wishes to express his sincere appreciation to Dr. E. S. Beneke whose interest, direction, and encourage- ment during the course of this work has made possible and facilitated its completion. Sincere thanks are also due to Drs. W. B. Drew, V. H. Mallmann and H. S. Potter for their many helpful suggestions, constructive criticisms, and much needed advice. This investigation was supported by a grant from the Michigan Cancer Foundation. iii TABLE OF CONTENTS Page LIST OF TABLES. . . . . . . . . . . . . . . . . . . . v LIST OF FIGURES . . . . . . . . . . . . . . . . . . . vi INTRODUCTION. . . . . . . . . . . . . . . . . . . . . 1 REVIEW OF THE LITERATURE. . . . . . . . . . . . . . . 3 MATERIALS AND METHODS . . . . . . . . . . . . . . . . 14 RESULTS . . . . . . . . . . . . . . . . . . . . . . . 23 DISCUSSION. . . . . . . . . . . . . . . . . . . . . . 38 SUMMARY . . . . . . . . . . . . . . . . . . . . . . . 49 LITERATURECITED................... 5]. APPENDIX. . . . . . . . . . . . . . . . . . . . . . . 58 iv Table II. III. Iv. LIST OF TABLES Page GROWTH OF SUILLUS LUTEUS AND SUILLUS ACIDUS IN MEDIUM A AT TWO SHAKER SPEEDS. . . . . . . . 24 GROWTH OF SUILLUS LUTEUS AND SUILLUS ACIDUS IN SYNTHETIC MEDIUM WITH VARIOUS NITROGEN SOURCES .>. . . . . . . . . . . . . . . . . . . 30 GROWTH OF SUILLUS LUTEUS IN SYNTHETIC MEDIUM WITH OPTICAL ISOMERS OF GLUTAMIC ACID . . . . . 32 GROWTH OF SUILLUS LUTEUS AND SUILLUS ACIDUS IN SYNTHETIC MEDIUM WITH SELECTED NITROGEN SOURCES . . . . . . . . . . . . . . . . . . . . 32 ANTITUMOR ACTIVITY OF SUILLUS LUTEUS AND- SUILLUS ACIDUS. . . . . . . . . . . . . ... . . 36 LIST OF FIGURES Figure Page 1. Growth curve of Suillus luteus in medium A at two shaker speeds . . . . . . . . . . . . . . . 25 2. Growth curve of Suillus acidus in medium A at two shaker speeds . . . . . . . . . . . . . . . 26 3. Growth curve of Suillus luteus in synthetic medium with L-glutamic acid . . . . . . . . . . 33 4. Growth curve of Suillus acidus in synthetic medium with L-arginine. . . . . . . . . . . . . 34 vi NITROGEN UTILIZATION AND PRODUCTION OF ANTITUMOR SUBSTANCES BY SUILLUS LUTEUS (FR.) S.F. GRAY AND SUILLUS ACIDUS (PECK) SINGER INTRODUCTION A recent article by Gregory gt al.(l966) indicates the interest in recent years in antitumor substances pro- duced by Basidiomycetes. Extracts from more than 7000 cul- tures produced by submerged fermentation were surveyed for antitumor activity in mice. Fifty extracts from cultures representing 20 genera produced an inhibitory effect on Sarcoma 180, Mammary Adenocarcinoma 755 or Leukemia L-1210. Antitumor activity in Basidiomycetes was first dem- onstrated by Lucas gt 31. (1957) in Boletus edulis. Accord- ing to the folklore the inhabitants of a small mountain village in eastern Bavaria ingested B, edulis to prevent cancer (Lucas, 1960). Several Calvatia species produced antitumor activity (Lucas gt 31., 1958-59). Further extensive physiologic studies of these organisms, especially Calvatia qiqantea, led tx) the development of strains that produced greater yields of the antitumor substance. Beneke (1963) reviewed this work in the Presidential address to the MycolOgical Society of America. Extracts of several species of Suillus produced ac- tivity against Sarcoma 180 (Beneke, unpublished data). Majid (1965) studied the carbohydrate requirements and their effect on the production of antitumor substances by two strains of Suillus luteus (Fr.) S.F. Gray. The purpose of this study was to determine the nitro- gen requirements and their effect on the production of anti- tumor substances by Suillus luteus and Spillus acidus (Peck) Singer when grown in submerged cultures. REVIEW OF THE LITERATURE There has been a vast amount reported on the nutri- tion of the fungi--even if one considers only nitrogen nutri- tion. It is not feasible to cover all the papers that have been written on this subject. Steinberg (1939, 1950) has summarized the principal work on the nutrient requirements of fungi in synthetic media. Two of the more notable reports on the early contro- versy of whether certain fungi could utilize free nitrogen as could certain bacteria were by Duggar and Davis (1916) and Allison, Hoover and Morris (1934). Duggar and Davis reported that the mycorrhizal species Phoma betae was able to utilize free nitrogen. Allison 22.2l- produced evidence to discount previous reports of nitrogen fixation by certain species of Asperqillus and Cladosporium. Nitrogen fixation did not occur among soil actinomycetes and they concluded that only certain mycorrhizal fungi may be capable of nitro- gen fixation. Cochrane (1958) concluded that there was no good evidence for nitrogen fixation by the fungi. Nicholas (1965) credits only the yeasts, Rhodotorula and Pullularia, with being able to fix atmospheric nitrogen. 3 An extensive study on nitrogen nutrition of fungi was done by Czapek (1902, 1903) with Aspergillus niger. Using almost all possible nitrogen sources known he concluded that proteins were most easily synthesized from amino acids or from substances closely resembling amino acids. A large number of Mucors were divided into two groups on their ability to assimilate nitrates and nitrites (Hagem, 1910). Nitrogen requirements were not fixed but varied with the source of carbon. A number of species could utilize ammonium or nitrate nitrogen with glucose but required nit- rate nitrogen with glycerol. Peptone, ammonium sulphate, ammonium nitrate and po- tassium nitrate were used as nitrogen sources for growing Aspergillus niqer, Sphaeropsis malorum and Qiplgdia natalen- sig in liquid cultures (Klotz, 1923). Peptone supported the best growth in all Species. The ammonium compounds and po- tassium nitrate varied in their order of ability to support growth. Klotz described autolysis which was indicated by a decrease in the mycelial dry weight after the utilization of the available carbon source. During autolysis ammonia was given off and amino acids appeared in the medium. Treschow (1944) did a complete nutritional study on the cultivated mushroom Psalliota bi3pora (syn. Agaricus campestris). Ammonium salts and the amino acids, glutamic acid and asparagine, were good sources of nitrogen. Nitrates did not support growth of the mycelium. Nine species of Marasmius grown in liquid cultures utilized ammonium nitrogen and asparagine (Lindeberg, 1944). Only one of the nine utilized nitrates. Twenty—one amino acids were utilized as sources of carbon for Fusarium oxysporum var. lycopersici and Penicil- lium roqueforti (Gottlieb, 1946). Seventeen could be util- ized as carbon sources. The six carbon straight chain amino acids, norleucine and lysine, and the sulfur contain- ing amino acids, cysteine and methionine, did not support growth. Some of the amino acids, including aSpartic acid and arginine, supported growth when used as a sole source of both carbon and nitrogen. Herrick (1940) and Herrick and Alex0poulos (1942) found peptone to be a good source of nitrogen for Stereum gausapatum. When thiamine was added to the medium, aspar- agine and ammonium nitrogen were good sources of nitrogen. Nitrate nitrogen failed to enhance growth even in the- presence of thiamine. Dimond and Peltier (1945) using Penicillgum notatum in liquid cultures studied the relation between pH of the medium and time of incubation as it is affected by varying the source of nitrogen or carbon. With nitrate nitrogen the pH dropped and then gradually rose regardless of the source of carbon. With amino acids the pH curve varied according to the source of carbon. They concluded that by supplying the proper nutrients the pH of the medium can be controlled during growth. Nineteen species of Coprinus were in some degree het- erotrophic for thiamine (Fries, 1955). Asparagine and am— monium nitrogen produced the best growth by most Species. Some species gave the best yields on aspartic acid or urea. Potassium nitrate was a good source for a few species but in general was inferior to the other forms of nitrogen. Steinberg (1937, 1939, 1942) reported on the nitrogen metabolism in Aspergillus niqer. Molybdenum was important in nitrogen metabolism, probably playing some role in the reduction of nitrates. Nitrate nitrogen, ammonium nitrogen, urea and certain amino acids were good and equivalent sources of nitrogen. Alanine, arginine, aspartic acid, glutamic acid, glycine, hydroxyproline, ornithine and proline were equiva- lent to inorganic nitrogen. Those amino acids with branched chains or stable cyclic structures were less effective as nitrogen sources than simple amino acids. Increase in the length of the carbon chain was accompanied by a decrease in assimilability. Sulfur containing amino acids were poor ni- trogen sources. Leonian and Lilly (1940) reported some factors that influence the growth in liquid cultures of various thiamine requiring fungi. Various organic acids were found to in- crease the availability of less favorable nitrogen sources such as arginine and ammonium nitrate. Growth in some cases was increased one thousand percent. Small quantities of am- monium nitrate added to aspartic acid increased the growth over that induced by either of these sources alone. A number of individual amino acids added to a basal medium containing ammonium tartrate stimulated the growth of Cenococcum qraniforme (Melin and Mikola, 1948). Melin and Norkrans (1948) reported that a nitrogen source of eighteen amino acids supported good growth of Lactarius deliciosus. A number of Tricholoma species assimilated ammonium nitrogen and organic nitrogen (Norkrans, 1950, 1953). Nit- rate nitrogen was utilized by only one Species. Glutamic acid and aSpartic acid, their correSponding keto acids, and also glutamine and aSparagine stimulated growth when added to a basal medIum already containing an ammonium nitrogen source. Twenty—five Species of fungi including fourteen Basidiomycetes were grown on three sources of nitrOgen (Hac- skaylo, Lilly and Barnett, 1954). Potassium nitrate was utilized slowly by the Basidiomycetes and very slowly if at all by the other fungi. Asparagine and ammonium sulfate sup- plemented with fumarate were about equal in supporting growth and better than ammonium sulfate or potassium nitrate. Bach (1956) reported the agaric Pholiota aurea grew best on surface cultures without agitation. .g. aurea util- ized ammonium salts, especially ammonium tartrate, aSpara- gine, glutamic acid, arginine, alanine, and urea. Better growth was on combinations like aSparagine-glutamic acid or asparagine-yeast extract. Yeast extract, peptone, melon juice and casein hydrolysate were better nitroqen sources than the individual amino acids. The organism failed to utilize nitrates. Fraser and Fujikawa (1958) found that the amino acids phenfkflanine, methionine and proline when added to a basal medium already containing asparagine Stimulated the growth of three strains of Aqarigus bisporus. The presence of thiamine was necessary for this growth response to occur. Optimal amounts of glucose, asparagine and inorganic salts for maximum growth of A, bisporus in liquid cultures were determined. Two strains of the dry rot fungus Merulius lacrymans var. domesticus utilized glycine, alanine, glutamic acid, aspartic acid, asparagine, oximide, acetamide, urea, uric acid and allantoin (Lamprecht, 1958). Ascobolus immersus could assimilate nitrogen in the form of potassium nitrate but Optimum yields were obtained with asparagine, aspartic acid, glutamic acid or urea (Yu- Sun, 1964). Kluyver and Perquin (1933) enunciated the principles involved in studying mold metabolism by the submerged culture methods. Foster (1949) discussed the merits of this method and the techniques for obtaining submerged growth. Humfeld (1948) successfully used the submerged cul- ture method to grow mycelium of the common cultivated mush- room, Aqaricus campestris, in a small Scale fermenter. Hum- feld and Sugihara (1949, 1952) described a method for growing 5, campestris on shake cultures. A synthetic medium for ob- taining good growth was determined. Urea was the nitrogen source used. 10 Forty-two species of wood-rotting Basidiomycetes were grown in submerged cultures (Jennison, Newcomb and Henderson, 1955). Thirty-eight species were deficient in thiamine. Am- monium salts, urea, casein hydrolysate and some of the amino acids supported growth. The differences in amino acid utili- zation were related to molecular structure. The simple mono- amino, monocarboxy amino acids of short chain length averaged significantly greater yields than those of longer chain length. Short chain amino acids with hydroxyl groups had similar yields to those simple ones of longer chain length. Sulfur containing amino acids and those with aromatic rings were poorly assimil- ated. The heterocylic forms varied from good to poor. Monoam- ino, dicarboxy acids were in general good sources of nitrogen. Morton and Macmillan (1953) in their classic study reported on the assimilation of ammonium salts and nitrates by Scopulariopsis brevicaulis. The failure of ammonium sul- fate to be completely assimilated was due to a drOp in pH to an inhibitory level. Various organic acids added to the medium acted as buffers to prevent this pH dr0p and allowed complete utilization of ammonium sulfate. Under correspond- ing favorable conditions ammonium nitrogen was assimilated faster than nitrate nitrogen. When ammonium and nitrates were available in the medium simultaneously, as with 11 ammonium nitrate, the ammonium was preferably assimilated until it drops to a very low level and then the nitrate is assimilated. This was due to the ammonium blocking the re- duction of nitrate to nitrite. The best single nitrogen sources for Collybia radi- cata var. furfuracea grown on shake cultures were: yeast extract, dried skim milk, malt extract, DL—serine and L- asparagine (Stevens, 1957). A low-temperature Basidiomycete utilized a number of amino acids and urea (Ward, 1964). Ammonium salts were well utilized if the pH was controlled by titration or by inclusion of organic acids in the medium for buffering. Nitrates were not utilized. Casein hydrolysate, peptone and asparagine were ex- cellent sources of nitrogen for the rust hyperparasite Q3;- lugg_filum in submerged cultures (Nicolas and Villanueva, 1965). Glutamic acid, glycine, aspartic acid and alanine were also good sources. The literature reveals little information concern- ing comparative nitrogen studies of the boletes. Melin (1922, 1923a, 1923b) succeeded in growing several Species of Boletus in a glucose—agar medium containing ammonium chloride as a nitrogen source. 12 Boletus eleqans was grown on agar medium by How (1940). Ammonium compounds were the best nitrogen sources. Potassium nitrate, asparagine and peptone were also utilized but growth was poor. Modess (1941) grew a number of hymenomycetes and gas- teromycetes in liquid cultures using asparagine and peptone as nitrogen sources. The effect of the hydrogen ion concen- tration on growth was studied extensively and the pH that supported optimum growth was determined. The optimum pH for growth of the Boletus Species was about 5. The pH that resulted in the optimum growth of Boletus luteus (syn. Suil- lus luteus) was 5.5. Reusser, Spencer and Sallans (1958) grew Boletus indecisus in submerged cultures on a medium containing mo- lasses and waste sulfite liquor supplemented with ammonium compounds. Falanghe (1962) grew this same organism in a medium of vinasse with ammonium sulfate added. Falanghe, Smith and Rackis (1964) grew Boletus indecisus in submerged cultures on a medium of soybean whey supplemented with ammonium sulfate, ammonium tartrate and ammonium acetate. Several reports on utilization of D—amino acids by fungi have appeared in the literature. Regnery (1944), Srb and Horowitz (1944) and Demain (1963) all reported that l3 mutant strains of Neurospora crassa could utilize certain D-amino acids. Emerson, Purziss and Knight (1950) found a strain of Penicillium chrysogenum able to utilize D—methionine and D-alanine as sole sources of nitrogen. D-amino acid oxidase activity was found in cell free extracts. Aspergillus flavus and A, parasiticus were able to assimilate several D-amino acids (Chibata, Tosa and Sano, 1964). Cell free extracts were shown to have D-amino acid oxidase activity. Blumer and Shopfer (1940) reported that Ustilago scabiosae assimilated both L and D isomers of certain amino acids. 9 Ward (1964) found a low-temperature Basidiomycete able to utilize D-alanine as well as L-alanine. Jennison and Perritt (1960) studied the utilization of optical isomers of amino acids by several wood-rotting Basidiomycetes. They found no utilization of D-amino acids when these were the sole source of nitrogen. MATERIALS AND METHODS Collection and Maintenance of Cultures Two species of Suillus were employed in this study: Suillus luteus (Fr.) S.F. Gray collected in the Lansing area in 1962 and designated as B-62-03, and Suillus acidus (Peck) Singer collected at the University of Michigan Biological Station near Burt Lake, Pellston, Michigan in 1963 and des- ignated as 3-63-50. The taxonomic characteristics of these two organisms are given by Smith and Thiers (1964). Original isolations were made from the basidiocarps. Bits of mycelium from inside the pileus were removed with a sterile needle and placed on agar slants. Cultures were maintained on bolete medium agar slants. Media Employed Bolete medium for maintenance of cultures: Malt Extract 5.0 g Glucose 5.0 g KH2P04 0.5 g M9804.7H20 0.5 g 15 NH4C1 0.5 g FeCl2 (1% solution) 0.5 ml Agar 15.0 g Distilled H20 1000.0 ml Medium A, a modified Czapek's—Dox medium, for grow- ing the inoculum (Stevens, 1957): Glucose 15.0 g Sucrose 15.0 g Bacto Peptone 5.0 g Bacto Yeast 5.0 g MgSO4'7H20 0.5 g KCl 0.5 g KH2PO4 1.0 g FeSO4 .7H20 0 .019 Agar (if solid medium required) 15.0 g Distilled H20 1000.0 ml The basal synthetic medium used in this study was the same as that used by Treschow (1944) and modified by Fraser and Fujikawa (1958). Fraser and Fujikawa found that a medium with 3 or 4 grams of L-asparagine and 30 or 40 grams of glucose gave optimum yields of mycelium, which were higher than the yields produced when the medium con- tained 1 gram of L-asparagine and 10 grams of glucose. 16 For this nitrogen study it was decided to use 40 grams of glucose and an amount of nitrogen equivalent to the amount found in 4 grams of L-asparagine. To determine how much growth could be attributed to carry over of nutrients with inoculum, a control was used leaving the nitrogen source out of the synthetic medium. This was designated as N—free medium. The ingredients of the basal synthetic medium were as follows: Glucose 40.0 9 KCl 0.2 g MgSO4.7H20 0.2 g KH2P04 0.14 g NaZHPO4.12H20 1.9 g CaC12.2H20 0.27 g FeCl3.6H20 0.017g H3BO3 0.01 mg CuSO4.5H20 0.1 ‘mg MnSO4.4H20 0.02 mg ZnSO4.7H20 2.0 mg MOO3 0.02 mg The pH was adjusted to 5.5 by addition of 1N NaOH or 6N HCl. The pH was determined by a Coleman pH meter. 17 The inorganic mineral elements were added from stock solutions. These stock solutions were prepared at the fol— lowing concentrations (the amount of stock solution to make 1 liter of medium is indicated in parenthesis): 2.0 g KCl in 100 ml distilled water (10 ml); 1.4 g KH P0 in 100 m1 2 4 distilled water (10 ml); 2.7 g CaC12.2H20 in 100 ml distilled water (10 ml); 9.5 9 Na HPO .12H 0 in 100 ml distilled water 2 4 2 (20 ml); 0.17 g FeCl3.6H20 in 100 ml distilled water (10 ml); 2.0 g MgSO4.7H20 in 100 ml distilled water (10 ml). The trace elements were combined in one solution: 0.0001 g H3B03; 0.001 g CuSO4.5H20: 0.0002 g MnSO4.4H20; 0.02 g ZnSO4.7H20; and 0.0002 g MoOBin 100 ml distilled water. Ten ml of the trace element solution were used to make 1 liter of medium. Sterilization and Cleaning All flasks and pipettes were washed in a hydrochoric- nitric acid cleansing solution, rinsed with tap water and distilled water. All media were sterilized at 1210C except urea. The appropriate amounts of a Seitz filtered urea solution were added to the sterile basal synthetic medium. 18 Mice and Tumor Maintenance The mice were Female Swiss albinos between 18 and 22 grams in weight. The tumor was Crocker Mouse Sarcoma 180 which was maintained by weekly transfers to different mice. Experimental Procedure To prepare for the differential nitrogen tests, Petri dishes with medium A were inoculated at 4 points and incubated for 15-20 days at 25°C. The individual colonies of Suillus luteus reached a diameter of about 20-30 mm; those of Suillus acidus about 15-20 mm. Twelve colonies were cut out and transferred with a sterile needle to a sterilized Waring blendor, 60 ml of sterile distilled water added and the mixture blended for 30 seconds. With a sterile 5 or 10 ml pipette 5 m1 of the blended mycelium were trans- ferred to each 250 ml Erlenmeyer flask containing 50 ml of medium A. The mycelium was grown on a rotary shaker for 10-13 days. The mycelium from these flasks was transferred to the synthetic medium. The synthetic medium was generally inoculated from medium A cultures that had been grown for 12 days. The my- celium in one flask was sufficient to inoculate a maximum of 10 flasks containing synthetic medium. The medium A was decanted from the mycelium. The mycelium was then washed 19 with 20 ml of sterile distilled water and the water decanted. This was repeated twice making a total of three rinsings to reduce the nutrients on the surface of the mycelium. Sixty m1 of sterile distilled water were added to the washed my- celium, poured into a sterile Waring blendor, and blended for 25 seconds. Five ml of the homogenate were transferred with pipettes to the 250 ml Erlenmeyer flasks containing 50 ml of synthetic medium. All flasks were capped with 2 layers of sterilized aluminum foil. The flasks were rotated in a constant temperature room at 250C. For each nitrogen source mycelial dry weights from 3 flasks were averaged at 10 and 15 day intervals. An addi- tional flask containing medium A was inoculated with mycelium from the same source as a growth control. The amount of growth was determined by the dry weights of the mycelium. Sargent filter papers (# 500) were numbered and dried in the oven for 5 to 6 hours at 85°C. The weight of each paper was taken immediately upon removal from the oven and recorded. The contents of the experimental flasks were filtered through these papers using a Buchner funnel and vacuum pressure. The mycelium on the filter paper was washed several times with distilled water and dried at 850C for 12 hours. The weight of the filter 20 paper and mycelium was determined immediately and recorded. The weight of the mycelium was determined by subtracting the weight of the filter paper. Growth curve experiments were established for both organism when grown on medium A and the synthetic medium. Amino acids that supported good growth were used as nitrogen sources in the synthetic medium: L-glutamic acid for growing g, luteus and L-arginine for growing g, acidus. Intervals of 5, 10, 15, and 20 days were usually used for growth curve experiments utilizing medium A. Averages were taken at 10, 15, 20, and 25 days for growth curve experiments utilizing the synthetic medium. Shaker speed was 150 rpm except for one growth curve experiment on medium A which was run at 120 rpm. Antitumor Activity Tests Several crude extracts were tested for antitumor activity in the mice. The trials were divided into two dif- ferent experiments. In the first experiment extracts from the synthetic medium were tested. These extracts were from cultures with nitrogen sources giving better mycelial growth. L-glutamic acid and DL—alanine were used for growing g, luteus. L-arginine was used for growing g, acidus. Extracts of g, luteus grown with L-glutamic acid were taken from 10, 21 15, and 20 day cultures. Extracts of S. luteus grown with DL—alanine and S, acidus grown with L—arginine were taken from 10 and 15 day cultures. In the second experiment extracts were taken from cultures of S. luteus and g. acidus that had been grown in medium A for 10 and 15 day periods. To prepare extracts for testing the mycelium in the medium was blended for 60 seconds in a Waring blendor. This mixture was filtered under vacuum with a Buchner funnel using Sargent filter paper (# 501). The filtrate was filtered through a sterilized Seitz filter under vacuum. The result- ing filtrate was dispensed into sterile serum bottles which were capped with sterile rubber caps. Extracts from two flasks were sufficient for testing a single group of mice for one week. An 0.85% saline solution was used as a control. Groups of 6 mice were used for the control and for each extract tested for antitumor activity. Tests were over a 9 day period. On Day 0 the mice were inoculated subcutan- eously with the tumor in the axillary region of the mouse with a 16 gauge trocar. Tumors were cut with a sterile scal- pel into uniform pieces approximately 1 mm cubed in a Petri dish containing a solution of 0.85%.saline and 0.1% chloram- phenicol. 22 The mice were weighed on Day 1 and Day 8. The mean weight per mouse was calculated. Injections of the test material were made daily be- ginning on Day 1 and continuing through Day 7. One ml in a disposable syringe was injected per mouse intraperitoneally. On Day 8 the mice were killed and the tumors removed and weighed. Evaluation of the data was based on the protocol of the Cancer Chemotherapy Reports (1962). RESULTS Growth Curves on Medium A and Effect of Shaker Speed The earlier experiments established growth curves of Suillus luteus and Suillus acidus when the two organisms were grown in medium A. The first growth curves were determined when the organisms were grown with a shaker speed of 120 rpm, and subsequently at a speed of 150 rpm. The results are shown in Table I, Fig. l and Fig. 2. Suillus luteus and Suillus acidus both have the four general phases of growth (Cochrane, 1958; Mandels, 1965): 1) The lag phase with relatively little increase in the amount of mycelium; 2) The exponential or 10garithmic phase where the mycelium is increasing at a uniform rate; 3) The stationary phase where no new mycelium is being formed or if it is being formed is balanced by autolysis; and 4) The auto- lytic phase characterized by the breakdown of carbohydrates and proteins. Increasing the shaker speed reduced the lag phase, the time from inoculation to the beginning of the exponential growth. With the shaker speed at 120 rpm relatively little 23 24 growth has occurred for either organism at the end of the five day period. At 150 rpm at least three-fourths of the total growth had occurred in five days. The results in Table I indicate that the stationary phase was reached more rapidly when the time of lag phase was reduced. With the Shaker speed at 120 rpm, the highest recorded mycelial dry weights are at the end of the 15 day The highest recorded mycelial dry weights at the ‘ period. 150 rpm shaker speed occurred at the end of the 10 day period. TABLE I GROWTH OF SUILLUS LUTEUS AND SUILLUS ACIDUS IN MEDIUM A AT TWO SHAKER SPEEDS Dry Weight of Mycelium in mg 5 10 12 15 20 25 120 rpm days days days days days days Suillus luteus 31 376 - 381 243 232 Suillus acidus 15 108 - 423 345 289 150 rpm Suillus luteus 287 351 315 226 216 - Suillus acidus 300 380 359 346 326 - Each figure is an average of four repliEates l 25 SOHDOQDUSH mo mama mm ON ma OH m b L . . _ 4 8mm omH n O emu oma u < IOOH O FOON. / Q / O < O/ 0 100m 0 a. < < .09. 600m .mpwmmm memflm o3u um m ESHUUE SH mswusa mSHHMDm mo m>HDU £u3ouwlu.a muomflh 6m uI tuIaM K10 26 coHquDUcH mo mama mm om ma OH m _ F . . F 4 BAR omH u Emu ONH u IOOH loom 4 O I oo... floov hoom .mommmm umxmnm oBu um < EsflOmE SH mopflom mDHHHSm mo m>uso £u30u0|1.m musmflm 6m uI qubIsM Ala 27 In the experiment with shaker speed at 150 rpm data was taken at the 12 day period. The mycelial dry weight was already lower than that recorded at the 10 day period. By the general appearance of the curves in Figures 1 and 2 the stationary phase probably occurred about 1 or 2 days before the 10 day period. In the experiment with the shaker speed at 120 rpm the stationary phase for Suillus acidus probably occurred at or very near the 15 day period (Fig. 2). For Suillus luteus the situation was somewhat more complex. The dry weight recorded for the 10 day period is nearly the same as that recorded for the 15 day period. It is hard to conceive that the stationary phase of growth extended over this 5 day interval. It seems more likely that the value at the 10 day period represents a point in the exponential phase of growth and that the value at the 15 day period represents a point in the autolytic phase. The stationary phase probably occurred at around 13 days. Nipgggen Requirements in Synthetic Medium The results of the growth promoting effect of the various nitrogen sources on Suillus luteus and Suillus acidus in the synthetic media are given in Table II. Mycelial dry weights of at least three replicates were taken at 10 and 15 28 day periods. PH readings were also an average of not less than 3 replications and were taken at 10 and 15 day periods. The shaker speed was 150 rpm. Also included in Table II are the mycelial dry weights of the medium A flasks used to check the viability of the inoculum. Accurate mycelial dry weights of g. luteus and S. acidus grown on cupric nitrate, L-tyrosine, L-cysteine and L-cystine could not be determined because of insoluble com- pounds in the medium at the time for taking dry weights. The growth of both organisms on these four nitrogen sources was poor. The two nitrates listed in Table II, potassium nit- rate and calcium nitrate, supported very little or no growth of §, luteus or g, acidus. Calcium nitrate shows no appre- ciable difference from the N-free medium for growth of either species. Potassium nitrate did not support growth of g, acidus, but supported some growth of g. luteus, since there was an increase of 24 mg over the dry weight of the N-free medium at the 15 day period. The ammonium compounds used supported growth of both organisms. Growth of s, acidus was enhanced more than growth of g, luteus. Ammonium chloride supported better growth of both organisms than did ammonium nitrate. Ammonium nitrate 29 is considered a form of ammonium nitrogen because it has been shown that when both forms are present in the medium at the same time the ammonium form is preferably used (Morton and MacMillan, 1953; Foster, 1949). Urea did not support growth in either species. The mycelial dry weights failed to reach the level of the N—free medium. Certain of the amino acids supported the best growth of g, luteus and g, acidus. The growth of S. luteus will be considered first. Comparisons of the dry weights will be made at the 15 day period. Of the sixteen amino acids used, seven did not enhance any growth above the N-free medium. These were DL-methionine, DL-phenylalanine, L-leucine, gly- cine, DL-valine, L-histidine, and L-proline. The other nine resulted in growth of S, luteus. L-alanine was the best nitrogen source followed by DL—alanine and L-glutamic acid. The others listed in decreasing order of ability to support growth were L—aSpartic acid, L-arginine, DL—serine, L-aspar— agine, L-lysine, and DL—isoleucine. DL-isoleucine was about equal to ammonium chloride in its ability to support growth. 30 c6 vows 6636 mm ESHDUOEH mo .UUHSOm ammouu6c umaso6uumm 6 60m ED6OOE UHpmnwcmm $06906 mEmm m26>mn d ESHUUE mo xmmam 0:0 mo unm60366 .6666066mm6 woman ummma um mo mmmum>< 6 .OUUESHEmuSOU I 666 6.6 66 6.6 66 666 6.6 66 6.6 66 6:66oumn6 666 6.6 66 6.6 66 666 6.6 666 6.6 666 mc6ummu6a 666 6.6 66 6.6 66 666 6.6 666 6.6 666 ma6osm6om6uqa 666 0.6 666 6.6 666 666 6.6 666 6.6 666 6:6mm6u6 666 6.6 66 6.6 66 u 6.6 66 6.6 66 mc666um6gu6 666 6.6 666 6.6 666 666 6.6 666 6.6 666 6606 U6uummmmu6 666 6.6 66 6.6 66 666 6.6 66 .6.6 66 ma66m>u6a 666 6.6 666 6.6 666 666 6.6 666 6.6 666 6:6:6666n6 666 6.6 66 6.6 66 666 6.6 66 6.6 66 6660666 666 6.6 66 6.6 66 666 0.6 66 6.6 66 oc6osm6u6 666 666 666 mc6am6muq 666 6.6 666 6.6 666 666 6.6 666 6.6 666 .6662666 66666-66 666 6.6 666 6.6 666 666 6.6 666 6.6 666 6606 u6emus6mu6 666 6.6 66 6.6 66 666 6.6 66 6.6 66 666:66m6mcmgmuqn I 6.6 66 6.6 66 666 6.6 66 6.6 66 ma6co6numSu6o 666 6.6 66 6.6 66 u 6.6 666 6.6 666 mc6mmummmmn6 666 6.6 66 6.6 66 666 6.6 66 6.6 66 awn: 666 6.6 666 6.6 666 666 6.6 666 6.6 666 666662 666 6.6 666 6.6 666 666 6.6 666 6.6 66 6 602 62 666 6.6 66 6.6 66 666 6.6 66 6.6 66 A Omvmo 666 6.6 66 6.6 66 666 6.6 666 6.6 66 026 666 6.6 66 6.6 66 666 6.6 66 6.6 66 6666-2 s¥u3 6mm ¥u3 63m *u3 *Su3 *3& SUB 63m *u3 6 2:666: 6666 66 6666 66 6 as6omz 6666 66 6666 66 636606 msHHHDm msousa msaaflsm monsom somOHDHZ 5".“ IF! H mMUMDOm ZMUOMBHZ mDOHm¢> EHHS ZDHQME UHBMEBZWm ZH mDQHU< mDAQHDm QZ¢ mDmBDQ memMDm ho mfikOmw HH mflmdfi 31 The number of amino acids supporting good growth of .§- acidus was less than for S. luteus. Ten of the fifteen amino acids used that were not utilized were: L—asparagine, DL—methionine, DL-phenYEdanine, L-leucine, glycine, DL-valine, L-histidine, DL-isoleucine, DL-serine, and L-proline. This list includes all those that were not good nitrOgen sources for S, luteus. L-arginine was the best nitrogen source for S, acidus followed by L-lysine, DL—alanine, L-aspartic acid and L-glutamic acid. The growth in DL—alanine was roughly comparable to that in ammonium chloride. The pH for the 10 and 15 day periods are recorded in Table II. The initial pH of 5.5 in the medium should not have retarded mycelial growth. PH at the 10 and 15 day periods in most cases stayed within the range favorable to growth for both species. The ammonium compounds showed a considerable drop in pH. Urea had a pH near 8 at the 10 and 15 day periods. Utilization of Glutamic Acid OpticalgIsomers by Suillus luteus The results of the experiment to test the ability of .S. luteus to utilize the different optical isomers of glutamic acid as nitIOgen sources are given in Table III. L—glutamic acid and DL-glutamic acid supported growth of S, luteus equally well. D-glutamic acid did not support the growth of S, luteus. 32 TABLE III GROWTH OF SUILLUS LUTEUS IN SYNTHETIC MEDIUM WITH OPTICAL ISOMERS OF GLUTAMIC ACID Isomer Dry Weight of Mycelium in mg D—glutamic ac id DL—glutamic acid L-qutamic acid 10 days 27 402 392 '15 days 26 524 523 Each figure is an average of at least 3 replicates. Growth Curves on Synthetic Medium The results of the growth curve experiments when Suillus luteus and Suillus acidus were grown on the synthetic medium are given in Table IV, TABLE IV and Fig. 3 and Fig. 4. GROWTH OF SUILLUS LUTEUS AND SUILLUS ACIDUS IN SYNTHETIC MEDIUM WITH SELECTED NITROGEN SOURCES m Dry Weight of Mycelium in mg Sgillus luteus with L-glutamic acid Suillus acidus with L-arginine 10 days 15 days 430 540 250 441 Each figure is an average of four flasks. 20 days 25 days 481 430 591 577 33 SOHDOQSUCH mo mhma mm om m6 06 m b — 1| \I O ..Oflom UHEmusHmIA £663 ED6OOE U6umnus>m :6 656636 WSHHHSm mo m>usu £u3ouwll.m musmflm OOH OON 00m 006 com com 6m uI quram Ara 34 COHDmQDUCH mo mama . \L . :- P o/o ws6c6666lq £663 EDHOOE OHDwnucmm c6 msp6om 6:666Dm mo m>nso £6306011.6 musmflm uOOH ioom room .100? -IOOm -ooo ‘bm uI quram Ala 35 The greatest mycelial dry weight for Suillus lutegS was recorded at the 15 day period on synthetic medium, while on medium A at the same shaker speed the peak weight was at the 10 day period, indicating that the stationary phase of growth was reached later on the synthetic medium than on medium A. The greatest dry weight recorded for the synthetic medium using L-glutamic acid as the nitrogen source was roughly 200 mg more than for medium A. (See Fig. 3) The greatest dry weight recorded for S, acidus grown in synthetic medium with L-arginine occurred at 20 days as compared to 10 days when grown in medium A. The dry weight at 20 days on the synthetic medium exceeded the dry weight at 10 days on medium A by about 200 mg. The stationary phase of growth for S, acidus is reached later on the synthetic medium than on medium A. Growth in terms of total dry weight is better on the synthetic medium than on medium A. (See Fig. 4) Antitggpr Activity of Suillggflluteus and Suillgs acidus Several extracts of both Suillus luteus and Suillus acidus, grown on synthetic medium and medium A, were tested for antitumor activity in the mice. The results of these experiments are given in Table V. 36 TABLE V ANTITUMOR ACTIVITY OF SUILLUS LUTEUS AND SUILLUS ACIDUS Experiment #1: Synthetic media extracts Organism Days of Mean T/C Mean Animal and Incubation Tumor wt Weight Gain Nitrogen Source mg ' gm Suillus lgteus L-glutamic acid 10 128 59 5.0 15 102 47 4.1 20 103 47 3.8 DL-alanine 10 129 59 4.3 15 117 54 5.2 Suillus acidus L-arginine 10 138 63 4.8 15 115 53 4.4 Control* 218 2.4 S.D. = 153 Experiment #2: Medium A extracts Suillus luteus 10 317 94 2.4 15 101 30 3.0 Suillus acidus 10 184 55 3.7 15 336 100 1.8 Control* 336 1.8 S.D. = 208 *0.85%.Saline solution. T/C = mean tumor weight of treated group/ mean tumor weight of control group. S.D. = standard deviation of control group. 37 The best antitumor activity of the synthetic medium is given by Suillus luteus grown on L-glutamic acid. Ex- tracts of the 15 and 20 day cultures have a T/C ratio of 47%. In all cases there was an increase of antitumor activity in 15 day cultures over 10 day cultures. Extracts of S, luteus grown on DL—alanine and S, acidus grown on L—arginine were about equal in tumor inhibition. The mean animal weight gains showed that the extracts from the synthetic medium did not affect the growth of the test animals. All of the test group animals showed a greater mean weight gain than the control group. In three cases this gain was twice.or more than the gain of the control group. The data for the antitumor activity of the medium A extracts indicate greater production at a different phase. Extracts of S, luteus grown in medium A for 10 days showed only slight inhibition. At the 15 day period the T/C ratio was 30%, the best inhibition in this data. S, acidus shows a T/C ratio of 55% at the 10 day period but failed to show any inhibition at the 15 day period. The mean weight gains of the mice tested with medium A extracts were all as good or better than the mean weight gain of the control group. There was no inhibitory effect on the growth of the mice by the extracts of medium A. DISCUSSION It was reasonable to expect that good growth of Suillus luteus and Suillus acidus should occur in medium A. In addition to glucose, sucrose and certain inorganic ele— ments necessary for growth, the medium contains peptone and yeast extract. Analysis of peptone and yeast extract is given in the appendix. Many of the naturally occurring amino acids are present which would provide suitable nitrogen sources. Several vitamins are present, including thiamine which was required by Suillus luteus (syn. Boletus luteus) and was required or enhanced the growth of four other species of Boletus (Melin and Nyman, 1940). A number of inorganic elements are present that may be required by the organisms for good growth. When analyzing the results of any nutritional study the conditions under which the experiment was done must be considered. The nitrogen sources supporting the best growth under one set of conditions may vary under another set of conditions. Hagem (1910) demonstrated that the nitrogen re- quirements of a number of Mucors was not fixed but varied 38 39 according to the source of carbon. Christie (1958, 1959) found that the best nitrogen source for Phytophthora cactorum was dependent upon the initial pH and also the carbon source. In assigning a rank order to the nitrogen sources according to their ability to support growth it is recognized that these results may have shown some variation if the experi- ments had been carried out under other conditions. It is notable that the synthetic medium was not sup- plementedwith any growth factors or vitamins. It is well known that many Basidiomycetes require thiamine for growth (Jennison §£_S;., 1955; Melin and Nyman, 1940; YUsef, 1953; Sedlmayr, 1960; Fries, N. 1950; Fries, L. 1955). As stated earlier Melin and Nyman (1940) reported specifically that Suillus luteus (syn. Spletus luteus) required thiamine for growth. The amount of thiamine required to promote maximum growth is in the magnitude of l microgram per liter (Fries, 1965). Thiamine and any other growth factors required for growth could have been carried over in large enough quanti- ties with the inoculum which was grown in medium A. Nicholas (1965) states that "most groups of fungi utilize nitrate nitrOgen although some do not, e.g., some members of the Saprolegniaceae, Blastocladiales, and some 40 higher basidiomycetes." There are numerous reports in the literature that demonstrate the inability of many Basidiomy- cetes to utilize nitrate nitrogen. The nitrate compounds in this study failed to support growth of the organisms studied with the possible exception of potassium nitrate which may have supported a little growth of Suillus luteus. The ammonium compounds supported fair growth by each organism. These compounds showed a considerable drop in pH, a characteristic of ammonium salts of strong acids resulting from unequal utilization of the cation NH (Cochrane, 1958). 4 In many instances of nitrogen nutrition the decrease in pH was sufficient to reduce growth (Cochrane, 1958) and could have prevented larger yields of mycelium by S, luteus and S, acidus. Ammonium chloride was a better nitrogen source for both species than was ammonium nitrate. The organisms were unable to Utilize nitrate so only half the nitrogen in the ammonium nitrate was available. Both compounds had equiva- lent amounts of total nitrogen. Essentially ammonium chlor- ide had twice the amount of available nitrogen as ammonium nitrate. Urea, Which is a utilizable nitrogen source for many fungi (Cochrane, 1958), failed to support any growth of 41 Sgillus lggeus or Suiilus acidus. The high pH may have been inhibitory to growth. The pH values at the 10 and 15 day periods were near 8 or higher. Modess (1941) found that the Boletus species did not grow in a medium with an initial pH above 6.9. If the high pH developed early enough it could very well have inhibited the growth of the two organisms. It is not known what caused this rise in the pH, especially since very little growth occurred. Humfeld and Sugihara (1952) used urea.in their nutrition study of Aqaricus cam— pestris becadse its utilization does not affect the pH of the medium enough to inhibit growth. Cochrane (1958) stated that the pH of a medium can rise either by the absorption of anions or by the production of ammonia. Sudden release of the nitrogen in the form of ammonia from the urea could have been responsible for the rise in pH. It may have been that the urea was not compatible with something in the medium that caused it to break down and release ammonia. Another explanation may involve the presence of urease which Cochrane (1958) says is present in many of the fleshy Basidiomycetes. According to Foster (1949) urease catalizes the following reaction: - urease 3 NH2CONH2 H20 ’ 2NH3 + co2 42 It is possible that one of these phenomenon occurred to re- lease ammonia in large enough quantities to raise the pH to a level that inhibited growth. Steinberg (1942) working with Aspergillus niqer and Jennison 2E.§l- (1955) working with some wood-rotting Basidio- mycetes correlated the ability of these fungi to utilize amino acids with the molecular structure of the amino acids. No absolute set of rules can be set down since variability occurs with every fungal species studied. In general the ability of a particular fungus to utilize amino acids is re- lated to the length of the carbon chain, branching, cyclic structures present and the functional groups present. Sulfur containing amino acids are usually poor sources of nitrogen. Cysteine, cystine and methionine did not support growth of either S, luteus or S. acidus. Amino acids having cyclic structures are also gener- ally poor sources of nitrogen. The amino acids used in this study having cyclic structures were: phenyhflanine, proline, tyrosine, and histidine. None of these supported growth of S, luteus or S, acidus. Amino acids that support the best growth are usually found among the simple short chained monoamino monocarboxy forms, the monoamino dicarboxy forms and their amides, or 43 among the basic amino acids. Amino acids that supported the best growth of S, luteus and S, acidus were from these groups. Alanine a simple, short chained, monoamino monocar- boxylic acid was the best form of nitrogen for S, luteus. Both of the dicarboxylic acids, glutamic acid, and aspartic acid, supported very good growth of S. luteus. The amide of aspartic acid, asparagine, supported growth of S, luteus. The basic amino acids arginine and lysine were reasonably good nitrogen sources. Serine a short chained, monoamino monocarboxylic form with a hydroxyl group supported growth. The basic amino acids, arginine and lysine, supported the best growth of S, acidus, with arginine being the best nitrogen source. Alanine supported good growth. Aspartic and glutamic acid also supported some growth of S, acidus. Usually an increase in the length of the carbon chain is accompanied by a decrease in assimilability. Valine a simple monoamino monocarboxylic acid similar in structure to alanine but having an extra carbon did not support growth in either organism studied. Leucine an amino acid with a five carbon chain and a methyl group on the gamma carbon, likewise, did not support growth of either organism. Iso- leucine, however, supported some growth of S, luteus. 44 Glycine the shortest chained monoamino monocarboxylic acid did not support growth of either organism. The occurrence in nature of the L—forms of the amino acids is more common than the occurrence of the D-forms (Meister, 1965). Reports of utilization of the D-forms of the amino acids by fungi, especially by Basidiomycetes, are likewise considerably less than reports of utilization of the L-forms. The ability of fungi to utilize D-isomers of amino acids is attributed by Cochrane (1958) and Nicholas (1965) to the presence of D-amino acid oxidase. D-amino acid oxid- ase deaminates amino acids by the following reaction: R-CH(NH2)COOH + 1/2'02——) R-COCOOH + NH3. Theimmonia released is then incorporated into L-amino acids. Although D—amino acid oxidase is a general term its action is specific and its presence does not confer the ability to utilize all D-amino acids. Blumer and Schopfer (1940) found Ustilago scabiosae able to utilize D-valine, D-isoleu- cine and D-alanine but not D-leucine or D-phenylalanine- Ward (1964) found a low-temperature Basidiomycete able to utilize D-alanine but not D-asparagine. Suillus luteus failed to utilize D-glutamic acid and therefore did not have a D—amino acid oxidase specific for 45 the deamination of this amino acid. There is some indication in the data that S. luteus was also unable to utilize the D-isomer of alanine. DL— alanine was used as a nitrogen source and gave excellent growth, comparable to that of L-glutamic acid. An equiva- lent amount of L-alanine increased the growth by about 200 mg, indicating that more nitrogen was available from the L— form than from the DL—form. >Both Sp§l$us luteus and Suillus acidus produced anti- tumor substances when grown on the synthetic medium and on medium A. When grown on the synthetic medium there appeared to be a correlation between the production of antitumor sub- stances and growth of mycelium. The growth peak for Suillus luteus when grown with L—glutamic acid occurred at or near the 15 day period. The highest antitumor activity occurred from extracts of cultures grown for 15 days. There was no decrease in antitumor activity in the cultures that were grown for 20 days, indicating that the antitumor substances had not broken down with the onset of autolysis of the my- celium. Suillus luteus grown on DL—alanine and Suillus acidus grown on L-arginine showed similar results, the antitumor activity increasing with growth of mycelium. 46 Suillus luteus had the best inhibition in medium A at the end of 15 days. Inhibition was 70% and correlated with the work of Beneke (unpublished data) who reported Suillus luteus to have inhibition of 72% when grown on med- ium A. Almost no inhibition occurred at the 10 day period. Suillus acidus extracts reduced the tumor size almost by one half at the end of the 10 day period but failed to show any inhibition at the end of 15 days. Stevens (1957) working with Calvatia qigantea grown in medium A showed that variation in production of calvacin occurred with the age of the cultures. Young cultures did not produce the tumor inhibiting substances or sometimes produced substances that stimulated tumor growth. Once the antitumor substances were produced they could be lost with increasing age of the cultures. Majid (1965) found consid- erable variation in the amount of antitumor substances pro- duced by Sgillus luteus and acknowledged that this might have been due to the duration of the incubation period. It appears that when the organisms are grown on medium A there is a point in the growth cycle when optimum amounts of the antitumor substances occur. At points before and after this period of Optimum yields, less or no antitumor activity occurs . 47 Stevens (1957) correlated the ability of Collybia radicata var. furfuracea to produce antitumor substances with the source of carbon. He found that although several carbon sources gave good yields of mycelium, glucose, man- nose and galactose more consistently caused the organism to produce the tumor retarding principle. He found no re— lationship between the nitrogen source and the production of the tumor inhibiting principle. 6Cook (1962) and Majid (1965) also correlated antitumor activity with the carbon source utilized. Majid found utilization of glucose or sucrose to result in the largest production of antitumor activity by Suillus luteus. Glucose was the carbon source used in the synthetic medium of this study and was a favor- able carbon source for the production of antitumor substances by both Suillus luteus and Suillus acidus. The role of the nitrogen source in the production of the antitumor substance is not known. It certainly seems reasonable that with the organism involved in the production of the active substances, nitrogen sources supporting good growth are a prerequisite. The three nitrogen sources used in Experiment 1 on antitumor activity all supported good growth and all were favorable for the production of antitumor activity. Experiments on the exact chemical nature of the 48 antitumor substances may elucidate further the role of nutri— ents in its production by Suillus Sp. SUMMA RY The nitrogen requirements of Suillus luteus and Suillus acidus were studied. Growth curves were established for the two organisms when grown on medium A and the syn— thetic medium containing amino acids that supported good growth. Increasing the shaker speed resulted in the reduction of the lag phase of growth and an earlier stationary phase. Nitrates were not utilized by either species except po— tassium nitrate which may have supported very limited growth of S, luteus. The ammonium compounds supported a fair amount of growth by both species. Some of the amino acids were the best sources of nitro— gen. Amino acids that were utilized best by S, AEEEEE were: L-alanine, DL-alanine, L-glutamic acid, and L- aspartic acid. L-arginine and L-lysine supported the best growth of S, acidus. 49 50 Although L- and DL-glutamic acid were excellent sources of nitrogen for S. luteus, D-glutamic acid was not util- ized by this organism. Antitumor substances were produced by both S. luteus and ‘S. acidus when grown in medium A and the synthetic medium. 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APPENDIX Typical analysis of Bacto-Yeastprtract (Furnished by the Difco Laboratories Incorporated, Detroit 1, Michigan) EEESEET Ash 10.10 Total N 9.18 Chloride 0.19 Total Sulphur 1.39 2314 Lead 16.00 Arsenic 0.11 Manganese 7.80 Zinc 88.00 Copper ' 19.00 BLREEIE Phosphorus 0.89 Iron 0.028 58 Typical analysis ofigBacto—Yeast Extract--continued REESENI SiO2 0.052 Potassium 0.042 Sodium 0.32 Magnesium 0.03 Calcium 0.0406 Arginine 0.78 Aspartic acid 5.1 Glutamic acid 6.5 Glycine 2.4 Histidine 0.94 Isoleucine 2.9 Leucine i 3.6 Lysine 4.0 Methionine 0.79 Phenylalanine 2.2 Threonine 3.4 Tryptophane 0.88 Tyrosine 0.60 Valine 3.4 60 Typical Analysis of Bacto-Yeast Extract-—continued MICROGRAMjS PER GRAM Pyridoxine 20.00 Biotin I 1.40 Thiamine 3.20 Nicotinic acid 279.00 Riboflavine 19.00 Folic acid 0.30 61 Typical analysis of Bacto—Peptone (Furnished by Difco Labor— atories Incorporated, Detroit 1, Michigan) Total Nitrogen 16.16% Primary Proteose N 0.06% Secondary Proteose N 0.68% Peptone N 15.38% Ammonia N 0.04% Free amino N (Van Slyke) 3.20% Amide N 0.49% Mono-amino N 9.42% Di-amino N 4.07% Tryptophane 0.29% Tyrosine 0.98% Crystine (Sullivan) 0.22% Organic Sulphur 0.33% Inorganic Sulphur 0.29% Phosphorus 0.22% Chlorine 0.27% Sodium 1.08% Potassium 0.22% Calcium 0.058% Magnesium 0.056% 61 Manganese Iron Ash Lead Arsenic Zinc C0pper $102 Arginine Aspartic acid Glutamic acid Glycine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Valine Pyridoxine Biotin 62 Typicalpanalysis ofpSacto-Peptone—-continued Nil 0.0033% 3.53% 15.00 ppm 0.09 ppm 18.00 ppm 17 .00 ppm 0.042% 8.00% 5.90% 11.00% 23.00% 0.96% 2.00% 3.50% 4.30% 0.83% 2.30% 1.60% 3.20% 2.50 gamma/gm 0.32 gamma/gm 63 Thiamine 0.50 gamma/gm Nicotinic acid 35.00 gamma/gm Riboflavine 4.00 gamma/gm 64 Sormggas of the Amino Acids Employed (From Lilly and Barnett, 1951) Monoamino dicarboxylic acids: Aspartic acid: HOOC-CHz—CH(NH2)-COOH Glutamic acid: HOOC-CHz-CHz—CH(NH2)-c00H Amides of monoamino dicarboxylic acids: Asparagine: NHZOC-CHz-CH(NH2)-COOH Basic amino acids: Arginine: NH2-C (=NH) -NH-CH2-CH2-CH2-CH (NHZ) -COOH LySIne: NH2-CH2-CH2-CH2-CH2-CH(NHZ)-COOH Histidine: 4/CH\\ 1] I , H‘CHZ-CH (NHZ) ‘COOH Monoamino monocarboxylic acids: Glycine: CH2(NH2)-COOH Alanine: CH3-CH(NH2)-COOH Valine: (CH3)2-CH-CH(NH2)-COOH Leuc1ne: (CH3)2-CH-CH2-CH(NH2)-COOH Isoleucine: CH3-CH2—CH(CH3)-CH(NH2)-COOH Phenylalanine: C6H5-CH2-CH(NH2)-COOH Serine: CH2(OH)-CH(NH2)-COOH Tryosine: HO<<::::::::>—CH2-CH(NHZ)-COOH 65 Formulas of the Amino Acids Smployed--continued C —F——-——CH I 2 .Proline: CH CH-COOH 2\ / NH Sulfur-containing amino acids: Cysteine: CH2(SH)-CH(NH2)-COOH Cystine: HOOC-CH(NH2)-CH2-S-S-CH2*CH(NH2)-COOH Methionine: CH2(SCH3)CH -CH(NH2)-COOH 2 ua1|”13m1")qualuminumHuumu 2072