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Full-Text Articles in Life Sciences

Metagenomic Profiling Of Cave Biofilms, With A Focus On Chemolithoautotrophy And Pseudonocardiaceae, John A. Fulginiti Aug 2023

Metagenomic Profiling Of Cave Biofilms, With A Focus On Chemolithoautotrophy And Pseudonocardiaceae, John A. Fulginiti

Masters Theses

The dark, humid, and nutrient depleted conditions of caves set limitations on habitability and result in microbial diversity and community structures that differ from surface environments. Recent studies investigating cave microbiomes reveal that Pseudonocardiaceae, a family of bacteria belonging to the phylum Actinomycetota, are abundant in cave sediment and on rocks as subaerial biofilms, however little work has been done on attempting to characterize their diversity and metabolism within the environment. This study used shotgun metagenomics to characterize the functional potential of Pseudonocardiaceae, as well as other cave microbes, in cave site KN14 located in Knox County, Tennessee. Functions of …


Effects Of Protein Concentration And Beta-Adrenergic Agonists On Ruminal Microbial Communities In Finishing Beef Heifers, Alison P. Pfau May 2022

Effects Of Protein Concentration And Beta-Adrenergic Agonists On Ruminal Microbial Communities In Finishing Beef Heifers, Alison P. Pfau

Masters Theses

To improve animal performance and modify growth by increasing lean tissue accretion, beef cattle production has relied on use of growth promoting technologies such as beta-adrenergic agonists. These synthetic catecholamines, combined with the variable inclusion of rumen degradable (RDP) and undegradable protein (RUP), may improve feed efficiency and rate of gain in finishing beef cattle. However, research about the impact of beta-adrenergic agonists and protein level and source on the ruminal microbiome is limited. The objective of this study was to determine the effect of different protein concentrations and beta-adrenergic agonist (ractopamine hydrochloride; RAC usage) on ruminal bacterial communities in …


The Flavoprotein Rcla Is A Hypothiocyanous Acid Reductase, Irina Chapman Dec 2021

The Flavoprotein Rcla Is A Hypothiocyanous Acid Reductase, Irina Chapman

Masters Theses

Reactive chlorine species (RCS) - hypochlorous acid (HOCl), hypothiocyanous acid (HOSCN), and chloramines - are powerful antimicrobial oxidants generated by the innate immune system. Bacteria developed defense mechanisms against RCS, which are highly toxic for invading pathogens. One such defense system involves RclA, an enzyme from the flavin disulfide reductase family, which is massively upregulated upon exposure of Escherichia coli to RCS. Recent research suggests that RclA functions as a Cu(II) reductase to provide resistance against RCS. However, the exact mechanism used by RclA was subject to debate. In this study, we demonstrate that RclA is unlikely to function as …


Effects Of Traditional And Microbially-Focused Restoration Techniques On Soil Communities In Tallgrass Prairies, Zachary J. Whitacre Jun 2021

Effects Of Traditional And Microbially-Focused Restoration Techniques On Soil Communities In Tallgrass Prairies, Zachary J. Whitacre

Masters Theses

Tallgrass prairies have virtually disappeared in many parts of their former range due to the conversion of this ecosystem to farmland. In more recent years there have been efforts to restore these prairies on reclaimed agricultural land. However, these restored prairies do not resemble their remnant counterparts in many ways, such as in soil microbial community composition and metrics related to carbon storage. In Chapter 1, I show that bacterial communities in a restored prairie and an adjacent remnant prairie in southwest Michigan differ in their immediate and longer-term responses to prescribed fire, a commonly used prairie restoration and maintenance …


Rare Occurrences Of Free-Living Bacteria Belonging To Sedimenticola From Subtidal Seagrass Beds Associated With The Lucinid Clam, Stewartia Floridana, Aaron M. Goemann Dec 2015

Rare Occurrences Of Free-Living Bacteria Belonging To Sedimenticola From Subtidal Seagrass Beds Associated With The Lucinid Clam, Stewartia Floridana, Aaron M. Goemann

Masters Theses

Lucinid clams and their sulfur-oxidizing endosymbionts comprise two compartments of a three-stage, biogeochemical relationship among the clams, seagrasses, and microbial communities in marine sediments. A population of the lucinid clam, Stewartia floridana, was sampled from a subtidal seagrass bed at Bokeelia Island Seaport in Florida to test the hypotheses: (1) S. floridana, like other lucinids, are more abundant in seagrass beds than bare sediments; (2) S. floridana gill microbiomes are dominated by one bacterial operational taxonomic unit (OTU) at a sequence similarity threshold level of 97% (a common cutoff for species level taxonomy) from 16S rRNA genes; …


Revealing The Ecological Role Of Gemmatimonadetes Through Cultivation And Molecular Analysis Of Agricultural Soils, Mariam Naomi Fawaz May 2013

Revealing The Ecological Role Of Gemmatimonadetes Through Cultivation And Molecular Analysis Of Agricultural Soils, Mariam Naomi Fawaz

Masters Theses

Bacteria belonging to phylum Gemmatimonadetes are frequently detected in a variety of environments using culture-independent methods. Despite their ubiquity and prevalence, almost nothing is known about their physiology or ecology because so few strains have been isolated. The first objective of this study was to determine the distribution of Gemmatimonadetes within soil aggregates and the response of the relative abundance of Gemmatimonadetes to dry/wet cycling and soil management. The second objective was to analyze the effects of soil management, aggregate size, and atmospheric conditions on cultivability of Gemmatimonadetes. Universal and Gemmatimonadetes-specific 16S rRNA gene primers were used to …


Prevalence Of Copper Resistance Among Foliar Bacterial Pathogens Of Tomato In Tennessee, Jonathon Thomas Mixon May 2012

Prevalence Of Copper Resistance Among Foliar Bacterial Pathogens Of Tomato In Tennessee, Jonathon Thomas Mixon

Masters Theses

Foliar bacterial diseases are among the most important diseases of tomato. Bacterial spot is caused by four species: Xanthomonas euvesicatoria, X. vesicatoria, X. perforans, and X. gardneri, hereafter referred to as Xanthomonas spp. Bacterial speck is caused by Pseudomonas syringae pv. tomato and bacterial canker is caused by Clavibacter michiganensis subsp. michiganensis. Fixed copper products are relied upon extensively for control, due to a lack of effective and economical alternatives. Copper resistance in bacterial spot and speck pathogens has been reported worldwide. Copper resistance quite likely exists in Tennessee, but the extent has never been …