Microbial Physiology Commons^™

Metabolic Heterogeneity And The Roles Of Cody And Ccpa In Central Metabolism And S. Aureus Biofilm Formation., Logan L. Bulock

Theses & Dissertations

Staphylococcus aureus is a metabolically versatile human pathogen, causing disease in many areas of the body. Its versatility can be attributed to the fact that it utilizes a variety of tools to adapt to many different environments, including toxins to scavenge from the host and multiple transporters to compete for its preferred carbon sources. S. aureus can also survive in harsh conditions through biofilm development, which are notoriously recalcitrant to antibiotics and immune defenses. Biofilms exhibit marked heterogeneity, with division of labor for production of matrix components and differential gene expression among various niches within the biofilm.

In this study, …

Image-Based Microbiome Profiling Differentiates Gut Microbial Metabolic States, Sarwesh Rauniyar

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

The Role Of The Msaabcr Operon In Cell Wall Integrity And Programmed Cell Death During Biofilm Development, Bibek G C

Dissertations

Staphylococcus aureus is an important human pathogen in both community and health care settings. Biggest challenges with S. aureus as a pathogen is its ability to acquire antibiotic resistance and produce robust biofilms. In this work, we investigated the nature of the cell wall defect in the msaABCR operon mutant in the Mu50 (VISA) and USA300 LAC methicillin-resistant Staphylococcus aureus (MRSA) strains. Results showed that msaABCR-mutant cells had decreased cell wall thickness and cell wall crosslinking in both strains. These defects are most likely due to increased murein hydrolase activity and/or nonspecific processing of murein hydrolases mediated by increased …

Ecophysiology Of Toxic Bloom-Forming Cyanobacteria And Their Symbionts, Dominique J. Lockwood

Masters Theses, 2020-current

Currently, there is a pernicious microbe in the genus Microcystis that is putting the world’s freshwater resources at risk. A member of the phylum Cyanobacteria, otherwise referred to as blue-green algae, Microcystis forms massive algal blooms in lakes and has the potential to produce a toxin, which does not only harm humans, but also pets, livestock, and aquatic life. As recently as 2016, in the city of Toledo, Ohio, nearly 1 million residents went without clean drinking water for an entire weekend due to one of these Microcystis blooms. However, Microcystis does not only bloom in Ohio. In fact, …

Role And Regulation Of Staphylococcal Cell Death, Abdulelah Ahmed Alqarzaee S

Theses & Dissertations

The transition from growth to stationary phase is a natural response of bacteria to starvation and stress. When stress is alleviated and more favorable growth conditions return, bacteria resume proliferation without a significant loss in fitness. Although specific adaptations that enhance persistence and survival of bacteria in stationary phase have been identified, mechanisms that help maintain the competitive fitness potential of non-dividing bacterial populations have remained obscure. This dissertation demonstrates that staphylococci entering stationary phase following growth in excess glucose undergo regulated cell death to maintain the competitive fitness potential of the population. Upon a decrease in extracellular pH, the …

How Acetylation Regulates Metabolic Enzyme Function During Environmental Shifts, Jared Canonigo

Biological Sciences Undergraduate Honors Theses

Organisms such as Saccharomyces cerevisiae can regulate the mechanisms of proteins through post-translational modification. These modifications play a vital role in functional proteomic activity because they can regulate protein activity, localization, and interaction with other cellular molecules. Such modifications include phosphorylation, methylation, and acetylation. The metabolic mechanisms of yeast became of keen interest to our lab because our lab noticed many stress defense proteins were being acetylated during stress heat shock. Notably, Adh1p and Adh2p showed both an increase and a decrease in acetylation at two lysine residues (K315 and K314) overtime during heat shock respectively, though the exact function …

Identification Of Proteins That Contribute To Yeast Heat Stress By Lysine Acetylation, Weijia Shi

Biological Sciences Undergraduate Honors Theses

Evidence is emerging that protein lysine acetylation may be a novel type of post-translational modification (PTM) contributing to the mechanisms of yeast heat stress responses. Proteomics studies including ours have identified over 1,000 acetylated proteins in the yeast proteomes that are composed of about 6,000 proteins. Our lab recently identified 596 proteins that underwent acetylation changes during heat shock by mass spectrometry. However, the role of lysine acetylation on specific residues of specific proteins in yeast thermotolerance remains largely unknown. This study selected 43 proteins from our lab’s previous work and examined their possible contributions to yeast heat stress responses. …

Increasing Stress Tolerance In Saccharomyces Cerevisiae Using Lipocalin Genes, Ximena Leon

Honors Theses

Saccharomyces cerevisiae is a microorganism that is commonly used in industries, but its productivity is significantly hindered by its inability to resist high stress levels found in industrial processes. By increasing stress tolerance in S. cerevisiae, its role in industrial processes could be maximized. The objective of this study is to determine if complementation of lipocalin genes into the wildtype and knockout strains of S. cerevisiae can increase stress tolerance against a variety of stressors. We identified the knockout yeast strains, ALD3, ALD4, PDX3, and ILV1, as being sensitive to various stressors including salinity, heat, oxidative, and osmotic stresses. Arabidopsis …

Unraveling Host-Gut Microbiota Dialogue And Its Impact On Response To Immune Checkpoint Blockade, Alexandria Cogdill

Dissertations and Theses (Open Access)

Cancer is a disease with only one degree of separation, affecting one in two men and one in three women in their lifetimes; accounting for 1 of every 6 deaths. While cancer mortality rates continue to improve, incidence rates are expected to rise and shift through 2050 due to epidemiological and demographic transitions worldwide. As such, it is imperative to continue to investigate and improve our understanding of both disease etiology and hallmarks of response to treatment. Currently, conventional therapies include, but are not limited to, surgery, chemotherapy, and radiotherapy. However, within the past decade, major advances have been made …

Pathogenicity Of Staphylococcus Agnetis Associated With Lame Broilers With Osteomyelitis, Sura Faris Salih Zaki

Graduate Theses and Dissertations

We developed High Resolution Melt Analysis (HERMA) as a rapid and reliable molecular diagnostic assay for the detection and identification of the main bacterial species recovered from the blood and lesions of bacterial chondronecrosis with osteomyelitis (BCO) from the lame broilers at the University of Arkansas poultry research farm. Also, the present study confirms that raising young birds on suspended wire flooring has been proved to successfully induce lameness attributable to BCO with birds being more susceptible to bacteraemia than those that were raised on litter flooring. The newly described pathogen, Staphylococcus agnetis, has been reported to be overrepresented in …

Increasing The Frequency Of Periodic Spatial Disturbance Decreases Surface Attachment Protein Expression In Staphylococcus Aureus, Ivana M. Barraza

All HCAS Student Capstones, Theses, and Dissertations

Staphylococcus aureus is an opportunistic pathogen that can cause a variety of acute and chronic illnesses. The severity of these illnesses such as sepsis, necrotizing pneumonia, and toxic shock syndrome is measured through the virulence that S. aureus inflicts on its host. Methicillin-resistant S. aureus (MRSA) is commonly associated with secondary infections and is challenging to treat given the limited selection of antibiotics that are effective against it. Accordingly, novel approaches to reduce S. aureus pathogenicity are required. S. aureus regulates pathogenesis through a cell-to-cell communication system referred to as quorum sensing. Effective communication determines the production of two broad …

B12: The T Cell Co-Receptor Cd5 Alters Mouse Behavior And Gut Microbiome Composition, Kyle Reaveley

Annual Research Symposium

No abstract provided.

Yeasts Isolated From Traditional Brem Bali Show Stress Tolerance Phenotype Against Fermentation-Related Stresses, Audria Bayu Lenka, Rika Indri Astuti, Sri Listiyowati

Makara Journal of Science

The search for microbes, primarily yeasts with unique characters such as the tolerance against fermentation-related-stresses, is gaining significant interest nowadays. Traditionally made alcoholic beverages can be used as sources for such yeasts, given that during fermentation and storage, microbes may develop stress tolerance responses leading to naturally stress-tolerant yeast strains. In this study, we used an alcoholic beverage, that is, Brem Bali, as the source of potential yeast isolates. We isolated nine yeast isolates from two traditional Brem Bali products. All isolates showed tolerance against high glucose stress (40–50%) and sensitivity against high-temperature stress (37–50 °C). Notably, isolate BT5 showed …

Taxonomic Microbiome Profiling And Abundance Patterns In The Cacao (Theobroma Cacao L.) Rhizosphere Treated With Arbuscular Mycorrhizal Fungi And Bamboo Biochar, Angelbert D. Cortes, Nelly S. Aggangan, Rina B. Opulencia

The Philippine Agricultural Scientist

Biochar and arbuscular mycorrhizal fungi (AMF) are agricultural interventions adopted by farmers to improve the growth of crops in nutrient-deficient acidic soil, which relatively influence the biological properties in the rhizosphere. This greenhouse study investigated the changes in prokaryotic diversity in the rhizosphere of cacao plants grown in acidic soil with AMF and bamboo biochar (BB) for 15 months under nursery conditions. Metagenomic analysis of the V3-V4 region of the 16S rRNA gene of the rhizosphere with AMF, 15% BB, and AMF + 15% BB revealed that the addition of AMF and BB reduced the sample's diversity, but the treatments …

The Response Of Marine Synechococcus To A Landscape Of Environmental Stressors: A Proteomic Exploration, Dana E. Michels

Master's Theses

In the field of marine microbial ecology, many questions remain unanswered with regards to the physiological trade-offs made by phytoplankton to maximize growth (e.g., nutrient acquisition) and minimize loss (e.g., predation defenses). These tradeoffs, which occur at the cellular level, have wide reaching impacts on food web dynamics and global biogeochemical cycles. In the first chapter, we explored the use of a non-canonical amino acid (NCAA) technique, bioorthogonal non-canonical amino-acid tagging (BONCAT), in phytoplankton model systems. This technique has potential to work well in natural systems by enabling isolation of only newly synthesized proteins during an incubation period with the …

Mfd Affects Global Transcription And The Physiology Of Stressed Bacillus Subtilis Cells, Holly Anne Martin, Anitha Sundararajan, Tatiana S. Ermi, Robert Heron, Jason Gonzales, Kaiden Lee, Diana Anguiano-Mendez, Faye Schilkey, Mario Pedraza-Reyes, Eduardo A. Robleto

Life Sciences Faculty Research

© Copyright © 2021 Martin, Sundararajan, Ermi, Heron, Gonzales, Lee, Anguiano-Mendez, Schilkey, Pedraza-Reyes and Robleto. For several decades, Mfd has been studied as the bacterial transcription-coupled repair factor. However, recent observations indicate that this factor influences cell functions beyond DNA repair. Our lab recently described a role for Mfd in disulfide stress that was independent of its function in nucleotide excision repair and base excision repair. Because reports showed that Mfd influenced transcription of single genes, we investigated the global differences in transcription in wild-type and mfd mutant growth-limited cells in the presence and absence of diamide. Surprisingly, we found …

Inhibition Of Biofilm Formation By The Synergistic Action Of Egcg-S And Antibiotics, Shrameeta Shinde, Lee Lee, Tinchun Chu

Department of Biology Faculty Scholarship and Creative Works

Biofilm, a stress-induced physiological state, is an established means of antimicrobial tolerance. A perpetual increase in multidrug resistant (MDR) infections associated with high mortality and morbidity have been observed in healthcare settings. Multiple studies have indicated that the use of natural products can prevent bacterial growth. Recent studies in the field have identified that epigallocatechin gallate (EGCG), a green tea polyphenol, could disrupt bacterial biofilms. A modified lipid-soluble EGCG, epigallocatechin-3-gallate-stearate (EGCG-S), has enhanced the beneficial properties of green tea. This study focuses on utilizing EGCG-S as a novel synergistic agent with antibiotics to prevent or control biofilm. Different formulations of …

Characterizing The Physiology And Genetics Of Contact Dependent Growth Inhibiton Systems In Burkholderia Species, Alice Elizabeth Oates

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Contact-dependent growth inhibition (CDI) systems mediate interbacterial competition. The genes encoding these systems are widespread among Gram-negative bacteria, including Burkholderia pathogens. CDI systems of Burkholderia species are composed of two-partner secretion pathway proteins and function to deliver the toxic C-terminus of a polymorphic surface-exposed exoprotein BcpA (Burkholderia CDI protein A) to the cytoplasm of neighboring recipient bacteria upon cell-cell contact. Specific outer and inner membrane proteins facilitate BcpA translocation both out of the donor bacterium and into the recipient cell cytoplasm. Most Burkholderia species-specific CDI translocation factors in recipient cells are unknown. BcpA intoxication functions as a mechanism by …

Roles Of Non-Frankia Bacteria In Root Nodule Formation And Function In Alnus Sp., Kelsey Christine Mercurio

Honors Theses and Capstones

Plant roots are home to a wide variety of beneficial microbes; understanding and optimizing plant-microbe interactions may be critical to enhance global food security in a sustainable, equitable way. With the help of their nitrogen-fixing bacterial partner, Frankia, actinorhizal plants form symbiotic root nodules and play important roles in agroforestry and land reclamation. However, Frankia does not live alone in nodules, and the other microbial residents may contribute to nodule formation and function. We collected root nodules from alder trees (Alnus sp.) in 2018 and 2019, then isolated DNA and individual bacterial strains to characterize the nodule microbial …