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Oxygen, Ph, And Labile Organic Carbon As Possible Mechanisms For Algal Stimulation Of Bacterial And Fungal Production In Periphyton, Jennifer Nichole Harper
Oxygen, Ph, And Labile Organic Carbon As Possible Mechanisms For Algal Stimulation Of Bacterial And Fungal Production In Periphyton, Jennifer Nichole Harper
Master's Theses and Doctoral Dissertations
Algal photosynthesis can stimulate production of associated microbial heterotrophs; however,the mechanisms for this stimulation remain unknown. I incubated submerged Typha domingensis leaf litter in greenhouse mesocosms under low- and high-nutrient regimes and conducted microbial production assays after 79/80 (week 11) or 128/129 (week 18) days of colonization. I manipulated environmental factors (oxygen, pH, and labile organic carbon) affected by algal photosynthesis to test the hypothesis that one or more of these factors stimulates heterotrophic microbial production. In the low-nutrient treatments, bacterial production was increased by glucose addition during week 11 (p < 0.001) and by photosynthesis during week 18 (p < 0.05). Fungal production was stimulated by photosynthesis in the high-nutrient treatments during weeks 11 (p < 0.001) and 18 (p < 0.01) and by glucose during week 11 (p < 0.05). These results confirm that algal photosynthesis can increase heterotrophic microbial production and suggest that photosynthetic labile organic carbon (LOC) could be a stimulatory mechanism.
An Evaluation Of Co-Culture Parameters Effecting Antibiotic Production In Soil Microbes, Rebecca Lindow
An Evaluation Of Co-Culture Parameters Effecting Antibiotic Production In Soil Microbes, Rebecca Lindow
Master's Theses and Doctoral Dissertations
The rise of infections caused by antibiotic resistant bacteria, compounded by a reduction in antibiotic discovery and development, jeopardizes human health. Historically, antibiotics derive from secondary metabolites produced by soil microbes in pure culture, but recent genetic evidence suggests that microbes can produce more secondary metabolites than are currently observed. The modified crowded plate technique directly identifies antibiotic-producing soil microbes that were co-plated with a target pathogen. Here, this technique was refined by testing the effect of a D-alanine auxotrophic target pathogen rather than a prototrophic pathogen as well as investigating conditions most conducive to antibiotic production. Antibiotic producing conditions …
The External Microbiome Of Bats: Effects Of Season, Site, Host Species, And Body Region, Kyle G. George
The External Microbiome Of Bats: Effects Of Season, Site, Host Species, And Body Region, Kyle G. George
Master's Theses and Doctoral Dissertations
White-nose syndrome is a cutaneous fungal disease that has been detrimental to North American bats for over 10 years, but few investigators have examined the natural microbiota living on these mammals. I explored the influence of season, geographic site, host species, and body region on the external microbiome of four cave-hibernating and two migratory species. Automated ribosomal intergenic spacer analysis was used to profile bacterial communities from three cutaneous regions of 222 bats across winter and summer sites in Michigan, Illinois, and Kentucky. Season, site, host species, and body region all influenced the composition of external bacterial communities, but geographic …