Microbiology Commons^™

Long-Term Impacts Of Tillage, Cover Crops, And Nitrogen Rates On Microbial Community Dynamics And Soil Quality Parameters Under Continuous Cotton Production In West Tennessee, Lilian Wanjiru Mbuthia

Doctoral Dissertations

Microbial communities play a central role in nutrient cycling and soil quality in agro-ecosystems. This research focused on a comparative analysis of the microbial community structure and activity of soils on long-term (31 years) continuous cotton- Gossypium hirsutum L., production in West Tennessee under conservation agricultural (CA) and conventional tillage practices that included: Nitrogen (N) fertilizer rates (N-rates) (0, 34, 67 and 101 kg N per ha); Cover crops (Hairy vetch-Vicia villosa and winter wheat- Triticum aestivum, and a No Cover control); and Tillage (Till and No-till). It was expected that microbial diversity, activity and soil quality would be …

Comparative Genomics Of Microbial Chemoreceptor Sequence, Structure, And Function, Aaron Daniel Fleetwood

Doctoral Dissertations

Microbial chemotaxis receptors (chemoreceptors) are complex proteins that sense the external environment and signal for flagella-mediated motility, serving as the GPS of the cell. In order to sense a myriad of physicochemical signals and adapt to diverse environmental niches, sensory regions of chemoreceptors are frenetically duplicated, mutated, or lost. Conversely, the chemoreceptor signaling region is a highly conserved protein domain. Extreme conservation of this domain is necessary because it determines very specific helical secondary, tertiary, and quaternary structures of the protein while simultaneously choreographing a network of interactions with the adaptor protein CheW and the histidine kinase CheA. This dichotomous …

Diversity And Function Of Sulfur Cycling Microorganisms In Sediments From Subglacial Lake Whillans, Antarctica, Alicia Marie Purcell

Masters Theses

There is a growing consensus that metabolically and phylogenetically diverse assemblages of microorganisms mediate subglacial nutrient and elemental cycling. Subglacial Lake Whillans (SLW), located under 801 m of glacial ice, was recently penetrated using environmentally clean protocols. SLW is a permanently dark, cold (-0.5 °C [degrees Celsius]), and shallow (~2.2 m) freshwater lake beneath the West Antarctic Ice Sheet. The presence and diversity of key functional genes involved in dissimilatory sulfur oxidation and reduction were examined at various depths in two sediment cores taken from SLW. Our data show a diversity of sulfur transformation genes throughout the top 34 cm …

Transcriptomic Analysis Of Clostridium Thermocellum Populus Hydrolysate-Tolerant Mutant Strain Shows Increased Cellular Efficiency In Response To Populus Hydrolysate Compared To The Wild Type Strain, Jessica L. Linville, Miguel Rodriguez, Steve D. Brown, Jonathan R. Mielenz, Chris D. Cox

Microbiology Publications and Other Works

Background: The thermophilic, anaerobic bacterium, Clostridium thermocellum is a model organism for consolidated processing due to its efficient fermentation of cellulose. Constituents of dilute acid pretreatment hydrolysate are known to inhibit C. thermocellum and other microorganisms. To evaluate the biological impact of this type of hydrolysate, a transcriptomic analysis of growth in hydrolysate-containing medium was conducted on 17.5%?v/v Populus hydrolysate-tolerant mutant (PM) and wild type (WT) strains of C. thermocellum.ResultsIn two levels of Populus hydrolysate medium (0% and 10%?v/v), the PM showed both gene specific increases and decreases of gene expression compared to the wild-type strain. The PM had increased …

Systems Biology Of Microcystis Blooms, Morgan Michelle Steffen

Doctoral Dissertations

Cyanobacterial harmful algal blooms (cHABs) degrade freshwater lakes worldwide. Accumulation of nuisance biomass and production of noxious secondary metabolites can result in an expansive impact on both lake ecology and the surrounding communities. The cHAB forming organism Microcystis aeruginosa is known to produce the toxin microcystin, a compound nicknamed “fast death factor,” which has been implicated in animal poisonings and human liver failure and cancers. M. aeruginosa inhabits a wide range of freshwater lakes around the world, such as Lake Erie (USA/Canada) and Lake Tai (Taihu, China), and is often a dominant member of bloom communities. Such systems are well-studied …

Relationships Among Prochlorococcus Ecotypes Across Oceanic Temperature Ranges, Jeremy Werner Chandler

Doctoral Dissertations

Prochlorococcus, the world’s smallest known photosynthetic organism, is an open ocean cyanobacterium, thought to be globally significant in nutrient cycling. Genetically and physiologically distinct “ecotypes” of Prochlorococcus populate the world’s subtropical and tropical oceans. A few of these key ecotypes comprise the majority of these populations, with the dominant ecotypes frequently varying as a function of depth and latitude. The mechanisms underlying the specific distributions of the ecotypes remain poorly understood, but temperature was believed to play a key role in latitudinal partitioning. Quantitative PCR (Q-PCR) was used to assess ecotypic abundances across transects spanning the Pacific Ocean from 27°N …

Development Of An Experimental And Computational Platform For Enhanced Characterization Of Modified Peptides And Proteins In Environmental Proteomics, Ritin Sharma

Doctoral Dissertations

Over the last decade, mass spectrometry based proteomics has been established as the front-runner in systems-level protein expression studies. However, with the field progressing into research of more and more complex samples, novel challenges have been raised with respect to efficient protein extraction and computational matching. In this dissertation, various aspects in the proteomics workflow, including experimental and computational approaches, have been developed, optimized and systematically evaluated. In this work, some of the critical factors with respect to proteomics sample preparation, like available biomass, detergent removal methods, and intact protein fractionation to achieve deeper proteome measurements were evaluated. The presented …

Quantitative Characterization Of Proteins And Post-Translational Modifications In Complex Proteomes Using High-Resolution Mass Spectrometry-Based Proteomics, Zhou Li

Doctoral Dissertations

Mass spectrometry-based proteomics is focused on identifying the entire suite of proteins and their post-translational modifications (PTMs) in a cell, organism, or community. In particular, quantitative proteomics measures abundance changes of thousands of proteins among multiple samples and provides network-level insight into how biological systems respond to environmental perturbations. Various quantitative proteomics methods have been developed, including label-free, metabolic labeling, and isobaric chemical labeling. This dissertation starts with systematic comparison of these three methods, and shows that isobaric chemical labeling provides accurate, precise, and reproducible quantification for thousands of proteins. Based on these results, we applied this approach to characterizing …

Urea As A Nitrogen Source For Microcystis Aeruginosa, Bernard Shafer Belisle

Masters Theses

Over the last decade, Lake Erie has experienced annual harmful algal blooms events dominated by the toxic cyanobacterium Microcystis aeruginosa. It is still unclear what causes Microcystis blooms to occur, but there is broad agreement that eutrophication of freshwater systems from anthropogenic sources (urban, industrial, etc.), has led to their proliferation. In particular, the organic compound urea has been implicated as an important source of anthropogenic nitrogen, due to its increased use in agricultural practices. Currently, urea constitutes more than 50% of the nitrogen used for agricultural fertilizer globally, and its usage has increased more than a 100-fold over …

Fty720 (Fingolimod) Provides Insight Into The Molecular Mechanisms Of Multiple Sclerosis, Madelyn Elizabeth Crawford

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Multiple sclerosis (MS) is a neurodegenerative disorder caused by a prolonged immune- mediated inflammatory response that targets myelin. Nearly all of the drugs approved for the treatment of MS are general immunosuppressants or only function in symptom management. The oral medication fingolimod, however, is reported to have direct therapeutic effects on cells of the central nervous system in addition to immunomodulatory functions. Fingolimod is known to interact with sphingosine-1-phosphate (S1P) receptors, and the most widely- accepted theory for its mechanism of action is functional antagonism of the receptor. This review examines significant neuromodulatory effects achieved by functional antagonism of the …

Evaluation Of Novel Multi-Dimensional Tissue Culturing Methods Using Autonomously Bioluminescent Human Cell Lines, James Dean Webb

Chancellor’s Honors Program Projects

No abstract provided.

Quantitative Depth Profile Of Prochlorococcus In The Pacific Ocean, Benjamin Carter Calfee

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Prochlorococcus is a genus of extremely abundant marine cyanobacterium. This microbe is responsible for the majority of the primary production within marine environments and is thought to be the single most abundant photosynthetic organism. In addition to accounting for such a large portion of the world’s photosynthetic activity, Prochlorococcus functions with a genome much smaller than most other primary producers. Thus due to its general abundance and overall importance in oceanic ecosystems, an experiment was prompted to derive the spatial and numerical separation of the members of this genus across the Pacific Ocean through the use of quantitative polymerase chain …

Comparison Of Bacterial Communities Associated Spider Species Occupying Different Physical Environments, Jack Kang

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

No abstract provided.

Seroprevalence And Genetic Characterization Of Toxoplasma Gondii In Three Species Of Pet Birds In China, Wei Cong, Meng Qing-Feng, Hui-Qun Song, Dong-Hui Zhou, Si-Yang Huang, Ai-Dong Qian, Chunlei Su, Xing-Quan Zhu

Microbiology Publications and Other Works

Background

Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is one of the most common zoonosis worldwide, affecting a wide range of warm-blooded mammals and birds worldwide. However, no information on T. gondii infection in pet birds in China is available. Therefore, this study was performed to determine the prevalence of T. gondii infection in pet birds in Gansu province, China.

Methods

A total of 687 blood samples were collected from pet birds (Carduelis spinus, Alauda gulgula, Cocothraustes migratorlus) in three representative administrative regions in Gansu province, northwest China between August 2011 and September 2012 T. gondii antibodies …

The Microscope (2013-2014), Department Of Microbiology

The Microscope

No abstract provided.

Genome Sequence Of The Sulfitobacter Sp. Strain 2047-Infecting Lytic Phage Φcb2047-B, Nana Y.D. Ankrah, Charles R. Budinoff, William H. Wilson, Steven W. Wilhelm, Alison Buchan

Microbiology Publications and Other Works

We announce the complete genome sequence of a lytic podovirus, ΦCB2047-B, which infects the bacterium Sulfitobacter sp. strain 2047, a member of theRoseobacter clade. Genome analysis revealed ΦCB2047-B to be an N4-like phage, with its genome having high nucleotide similarity to other N4-like roseophage genomes.

Genome Sequences Of Two Temperate Phages, Φcb2047-A And Φcb2047-C, Infecting Sulfitobacter Sp. Strain 2047, Nana Y.D. Ankrah, Charles R. Budinoff, William H. Wilson, Steven W. Wilhelm, Alison Buchan

Microbiology Publications and Other Works

We announce the complete genome sequences of two temperate Podoviridae,Sulfitobacter phages ΦCB2047-A and ΦCB2047-C, which infect Sulfitobacter sp. strain 2047, a member of the Roseobacter clade. This is the first report of temperate podophage infecting members of the Sulfitobacter genus of theRoseobacter clade.