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Title: Dissecting the role of peroxisomes in modulating environmental stress response and photosynthesis
Creator: Li, Jiying
Date: 2015
Collection: Electronic Theses & Dissertations
Description: Peroxisomes are essential organelles that house a wide array of metabolic reactions important for plant growth and development. These organelles also interact with other organelles to support cellular functions. However, our knowledge regarding the role of peroxisomal proteins in various biological processes, including plant stress response and photosynthesis, is still incomplete. To address this question at the systems level, I exploited in silico analysis, mutant screens and in-depth...
Show morePeroxisomes are essential organelles that house a wide array of metabolic reactions important for plant growth and development. These organelles also interact with other organelles to support cellular functions. However, our knowledge regarding the role of peroxisomal proteins in various biological processes, including plant stress response and photosynthesis, is still incomplete. To address this question at the systems level, I exploited in silico analysis, mutant screens and in-depth physiological and biochemical characterizations. First, I used microarray data to generate a comprehensive view of transcript level changes for Arabidopsis peroxisomal genes during development and under abiotic and biotic stress conditions. Second, mutants of LON2 protease and the photorespiratory enzyme hydroxypyruvate reductase 1 (HPR1) were identified to have enhanced susceptibility to drought, suggesting the involvement of peroxisomal quality control and photorespiration in drought resistance. Third, I conducted a comprehensive peroxisomal mutant screen, in which 147 mutants of 104 Arabidopsis genes encoding peroxisomal proteins were subjected to an automated screening system, the Dynamic Environment Phenotype Imager (DEPI). This screen identified multiple peroxisomal proteins required for robust photosynthesis efficiency under dynamically changing light, including peroxisomal biogenesis and division proteins, photorespiratory proteins, and a NAD+ transporter protein PXN, which was found to be an additional player in photorespiration. Fourth, further characterization of the photorespiratory mutants provided insights into the molecular mechanisms regarding how the blocking of photorespiration alters photosynthetic efficiency. My data supported an integrated model for the events that occur in the photorespiration mutants, where metabolites and molecules resulting from the block of photorespiration inhibit triose phosphate isomerase (TPI) activity, compromise photosystem integrity, reduce photosystem subunit abundance, decrease proton efflux and diminish ATP synthase conductivity, induce cyclic electron flow (CEF) and activate energy dissipation. In summary, my work has provided significant insights into the connection between peroxisomal function and drought stress response and the links between photorespiration and photosynthesis. Knowledge gained from my dissertation research opens up new avenues to further investigate environmental stress response, photosynthesis, photorespiration and interorganellar communication.
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Title: Some factors affecting the determination of fatty acids and unsaponifiable matter in plant materials
Creator: Dill, John J.
Date: 1942
Collection: Electronic Theses & Dissertations

Title: Land use/land cover and water quality in the Muskegon River Watershed, Michigan : a case study
Creator: John, Ranjeet
Date: 2005
Collection: Electronic Theses & Dissertations

Title: Cis-regulatory code controlling spatially specific high salinity response in Arabidopsis thaliana
Creator: Seddon, Alexander
Date: 2015
Collection: Electronic Theses & Dissertations
Description: Plants are subjected to a variety of environmental stress, and their ability to respond to stress depends, in a large part, on the proper regulation of gene activities including transcription. Earlier studies show that the regulation of stress transcriptional response has a significant spatial component, namely, each organ, tissue, and cell type may respond to a stress by differentially regulating different sets of genes. Although our knowledge is accumulating on how specific transcription...
Show morePlants are subjected to a variety of environmental stress, and their ability to respond to stress depends, in a large part, on the proper regulation of gene activities including transcription. Earlier studies show that the regulation of stress transcriptional response has a significant spatial component, namely, each organ, tissue, and cell type may respond to a stress by differentially regulating different sets of genes. Although our knowledge is accumulating on how specific transcription factors (TFs) and their associated cis-regulatory elements (CREs) are involved in stress responses, a genome wide model of what plant TFs and CREs are key to the spatial stress response regulation has yet to emerge. In this study, a set of 1,894 putative CREs (pCREs) were identified that are associated with salt stress up-regulated genes in the root and shoot of Arabidopsis thaliana. These pCREs led to models that can better predict salt up-regulated genes in root and shoot compared to models based on known TF binding motifs. The full pCRE set could be broken into root, shoot and general subsets that are enriched amongst root, shoot, or both root and shoot salt up-regulated genes, respectively. We also identified pCRE subsets that are enriched amongst genes induced by salt in root cell-types. Most importantly, combinations of the pCRE subsets allowed predictions of genes up-regulated by high salinity in root, shoot, as well as various root cell types. In addition, consideration of pCRE combinatorial rules further improved salt upregulation prediction. Our results suggest that the organ and cell-type transcriptional response to high salinity is regulated by a core set of pCREs that need to be considered in combinations, and provides a genome-wide view on the cis-regulation of spatial transcriptional responses to stress.
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Title: A phytosociological study of an uplifted marine beach ridge near Point Barrow, Alaska
Creator: Koranda, John J. (John James)
Date: 1954
Collection: Electronic Theses & Dissertations

Title: An evaluation of attitudes towards wildlife
Creator: Schmidt, Wayne Arnold
Date: 1974
Collection: Electronic Theses & Dissertations

Title: Use of eye-tracking to more effectively merchandise plants
Creator: Jones, Allison Nicole
Date: 2014
Collection: Electronic Theses & Dissertations
Description: USE OF EYE-TRACKING TO MORE EFFECTIVELY MERCHANDISE PLANTSBy Allison Nicole JonesMaking the process of shopping easier or more enjoyable may bring positive benefits to both the shopper and the retailer. We used an eye-tracking device to investigate and execute two studies related to consumers' use of visual cues (signs) in retail garden center displays. In the first study we focused on informational signs that described that the plants were grown using water conservation practices and...
Show moreUSE OF EYE-TRACKING TO MORE EFFECTIVELY MERCHANDISE PLANTSBy Allison Nicole JonesMaking the process of shopping easier or more enjoyable may bring positive benefits to both the shopper and the retailer. We used an eye-tracking device to investigate and execute two studies related to consumers' use of visual cues (signs) in retail garden center displays. In the first study we focused on informational signs that described that the plants were grown using water conservation practices and separate survey questions about their water conservation practices. From this study we found that attention to the sign communicating water conservation production practices was linked to participants' home water conservation practices. Participants who were more likely to conserve water on their plants at home were also more likely to purchase plants that were grown under water saving practices than those participants that were not as likely to conserve water. Participants from Florida seemed to be more sensitive to water conservation signage than participants from non-drought areas such as Michigan and Indiana. The second study focused on consumers viewing of informational signs that described vegetable and herb transplants grown under sustainable production practices. From this study we were able to show differences in participants' weekly purchases of organic products and its relationship to first fixation duration (FFD) on the informational sign. Participants who spent a larger amount of their weekly budget on organic products had a longer FFD on the sign. Differences between participants who had children under the age of 18 in their household compared to participants who had no children in their household were also found.
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Title: Improving wildlife habitat model performance : sensitivity to the scale and detail of vegetation measurements
Creator: Roberts, Lance Jay
Date: 2009
Collection: Electronic Theses & Dissertations

Title: The systematics of the genus Amauropelta (Pteridophyta:Thelypteridaceae) in the Caribbean Islands
Creator: Alvarez-Fuentes, Orlando
Date: 2010
Collection: Electronic Theses & Dissertations

Title: Influence of preharvest herbicide applications on desiccation, yield and color retention of black beans
Creator: Goffnett, Amanda Marie
Date: 2015
Collection: Electronic Theses & Dissertations
Description: The retention of the black color in canned black beans is viewed as a key attribute in finished product quality and is very important for consumer acceptance. Changes in production practices and black bean varieties may influence canned black bean quality. A field trial was conducted near Richville, Michigan in 2013 and 2014 to evaluate the effects of preharvest herbicide treatments on desiccation, yield, and black bean quality and color. The black bean varieties Zorro, Eclipse, and Zenith...
Show moreThe retention of the black color in canned black beans is viewed as a key attribute in finished product quality and is very important for consumer acceptance. Changes in production practices and black bean varieties may influence canned black bean quality. A field trial was conducted near Richville, Michigan in 2013 and 2014 to evaluate the effects of preharvest herbicide treatments on desiccation, yield, and black bean quality and color. The black bean varieties Zorro, Eclipse, and Zenith were planted on two different dates in each of two years. Three preharvest herbicide treatments, paraquat, glyphosate, and saflufenacil, were applied at two different application timings. Differences in black bean desiccation were greatest 3 DAT, with paraquat and saflufenacil showing the quickest desiccation. By 7 DAT, desiccation for most preharvest treatments was over 95%. Early applications of saflufenacil in the first planting had the greatest impact on yield for both years when compared with the nontreated control. Black bean color was lighter when glyphosate was applied early to Zenith and Zorro as assessed by a panel of over 20 evaluators. Lightness (L*) measurements also indicate lighter black bean color after canning with early applications of glyphosate. Eclipse had the lightest L* measurements while Zenith had the darkest, regardless of planting date or application timing. Overall, preharvest herbicides applied at the early application timing reduced black bean yield, with the largest reduction observed from applications of saflufenacil. The greatest loss of black color in canned beans was observed when glyphosate was applied at the early application timing; however, preharvest treatments applied at the standard timing very rarely impacted bean color.
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Title: Shedding light on euglenoid evolution and systematics through the chloroplast genomes of Euglena viridis and Euglenaformis (Euglena) proxima
Creator: Bennett, Matthew Scott
Date: 2013
Collection: Electronic Theses & Dissertations
Description: The chloroplast genomes of Euglena viridis and Euglenaformis [Euglena] proxima were sequenced and analyzed against the chloroplast genomes of other previously sequenced algal taxa. The chloroplast genome of E. viridis was sequenced in order to explore intrageneric chloroplast evolution, and our results revealed that while the chloroplast genome of E. viridis closely resembled that of Euglena gracilis, it did show significant differences. The chloroplast genome of E. viridis was far more...
Show moreThe chloroplast genomes of Euglena viridis and Euglenaformis [Euglena] proxima were sequenced and analyzed against the chloroplast genomes of other previously sequenced algal taxa. The chloroplast genome of E. viridis was sequenced in order to explore intrageneric chloroplast evolution, and our results revealed that while the chloroplast genome of E. viridis closely resembled that of Euglena gracilis, it did show significant differences. The chloroplast genome of E. viridis was far more compact, had a gene cluster that was reversed in both gene order and strand orientation, had a region that was comprised almost entirely of open reading frames, and had substantially fewer introns than E. gracilis. However, despite these differences, it was clear that the majority of chloroplast evolution in the genus Euglena probably occurred before its divergence from the rest of the photosynthetic euglenoids. The chloroplast genome of E. proxima was sequenced in an attempt to clarify its relationship to the rest of the photosynthetic euglenoids. Genetic data obtained from the chloroplast genome sequence were used in phylogenomic analyses to compare 78 chloroplast-encoded genes from E. proxima with those found in six photosynthetic euglenoids and three prasinophytes. The results of these analyses were consistent with the results of previous phylogenetic analyses using a small number of small subunit and large subunit rDNA genes and supported the position of E. proxima as sister to all of the Euglenaceae. Based on these data, E. proxima was removed from the genus Euglena, and a new genus, Euglenaformis, was erected for this taxon.
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