Microbiology Commons^™

The Ecological Responses To Hydroperiod Of Wetland Plant Species Determined By Manipulated Soil Surface Elevation (Marsh Organs), Brandon Wolff

LSU Master's Theses

As sea level rise, subsidence, and abandonment of natural deltaic processes due to a highly engineered Mississippi River continue to threaten Louisiana’s coastal wetlands, the need for a system-wide understanding of natural wetland land-building and preservation processes has never been greater. A key component of any wetland is the ever-changing water environment that periodically floods and dries the marsh platforms. The flooding depth, duration, and frequency, known as the hydroperiod, along with salinity and soil fertility are key determining factors of vegetation and marsh types at a particular location. Different types of vegetation will have different growth characteristics such as …

Secreted Igm Modulates Il-10 Expression In B Cells, Shannon Mcgettigan, Lazaro Aira, Gaurav Kumar, Romain Ballet, Eugene Butcher, Nicole Baumgarth, Gudrun Debes

Department of Microbiology and Immunology Faculty Papers

IL-10⁺ B cells are critical for immune homeostasis and restraining immune responses in infection, cancer, and inflammation; however, the signals that govern IL-10⁺ B cell differentiation are ill-defined. Here we find that IL-10⁺ B cells expand in mice lacking secreted IgM ((s)IgM^–/–) up to 10-fold relative to wildtype (WT) among all major B cell and regulatory B cell subsets. The IL-10⁺ B cell increase is polyclonal and presents within 24 hours of birth. In WT mice, sIgM is produced prenatally and limits the expansion of IL-10⁺ B cells. Lack of the high affinity …

The Influence Of Environmental Parameters On Gordonia Terrae - Specific Bacteriophage Abundance And Diversity, Gt M. Moore, Uqueen C. Wheeler, Indiren Pillay

Graduate Research Showcase

Bacteriophages are viruses that infect a wide variety of host bacteria with some strains having medical and industrial significance. These highly abundant and genetically bacterial viruses constitute a large amount of unexplored genetic information. Because bacteriophages are highly specific, they can be used therapeutically to combat bacterial infections by selecting a phage to target and kill harmful bacteria. Thus, phage therapy is currently being explored to aid in the fight against antibiotic resistance. Actinobacteriophages are viruses that specifically infect Phylum Actinobacteria hosts including the environmentally abundant Gordonia terrae. Some species of Gordonia, including G. terrae, have also …

The Presence Of Pathogenic Leptospira In San Juan Bay Estuaries And Its Relationship To Fecal Pollution Sources, Jodel M. Nicholas, Dave Bachoon Dr.

Graduate Research Showcase

The northern coastal zones of Puerto Rico, including the San Juan Bay and Rio Grande de Loiza watersheds, are increasingly becoming focal points of environmental concern due to wastewater originating from human activity. This runoff, which consists of effluents from sewage treatment, septic tanks, and animal husbandry, enters coastal lagoons and estuaries, posing critical threats to these vital ecosystems. This study aims to determine the presence of Leptospira in over 100 samples from 16 sub-basins over 2 years as well as identify the major sources of fecal pollution using molecular source tracking techniques. End point PCR assays for Leptospira (LipL32), …

Dpr-Mediated H2o2 Resistance Contributes To Streptococci Survival In A Cystic Fibrosis Airway Model System, Rendi R. Rogers

Dartmouth College Master’s Theses

The cystic fibrosis (CF) lung environment is conducive to the colonization of bacteria as polymicrobial biofilms, which are associated with poor clinical outcomes for persons with CF (pwCF). Streptococcus spp. is highly prevalent in the CF airway, but its role in the CF lung microbiome is poorly understood. Some studies have shown Streptococcus spp. to be associated with better clinical outcomes for pwCF, while others show that high abundance of Streptococcus spp. is correlated with exacerbations. Our lab previously reported a polymicrobial culture system consisting of four CF-relevant pathogens that can be used to study microbial behavior in a more …

Using Single Cell Genomics To Explore The Impact Of Marine Viruses On Microbial Respiration., Paxton Tomko

MCB Articles

Viral metabolic reprograming of marine prokaryotes, through the use of virally encoded auxiliary metabolic genes (AMGs), plays a critical role in marine ecosystem function by influencing biochemical cycles and genetic diversity in these environments. Despite the fundamental role viruses play in global environmental ecosystems, they remain an understudied aspect of microbial ecology and evolution, in part due to the methods available for studying virus host interactions in natural systems. Thus far, metagenomic analyses have been used to study the interactions of virus host pairs, but these types of analyses have their limitations in accurately linking viruses to hosts, or culture-based …

Evaluation Of Hormonal Suppression Treatments Of Endometriosis, Olivia Vermeulen

Biology and Microbiology Graduate Students Plan B Research Projects

Endometriosis is a chronic, multifactorial, and estrogen dependent disease that causes lesions made of endometrial tissue to implant in areas other than the uterus such as the ovaries, fallopian tubes, abdominal cavity, lungs, and even heart (1). These lesions can cause an immense amount of pain in the implanted area during the menstrual cycles and can cause infertility issues, but unfortunately there are not many available and effective treatment options available that do not involve surgically removing the lesions (2). However, there are certain hormonal suppression medications being that are new or are being tested that can alleviate inflammation and …

Analysis Of Protein-Protein Interactions Between Legionella Pneumophilia Effectors, Briana Harness

Mahurin Honors College Capstone Experience/Thesis Projects

Legionella pneumophila an intracellular, opportunistic pathogen that is the causative agent of Legionnaires’ disease and Pontiac fever. A key component of Legionella’s pathogenicity is a series of effector proteins, which aid in the establishment of the Legionella-containing vacuole (LCV). The abundant library of effector proteins L. pneumophila has within its arsenal gives L. pneumophila the ability to infect several different hosts. The pathogenesis of L. pneumophila within various hosts depends on its ability to modulate the activity of its effector proteins through protein-protein interactions within effectors and eukaryotic host cell proteins. By understanding how L. pneumophila regulates its effectors, a …

Artificial Intelligence, Big Data, And Regulation Of Immunity: Challenges And Opportunities, Bhagirath Singh, Anthony M Jevnikar, Eric Desjardins

Microbiology & Immunology Publications

The immune system is regulated by a complex set of genetic, molecular, and cellular interactions. Rapid advances in the study of immunity and its network of interactions have been boosted by a spectrum of "omics" technologies that have generated huge amounts of data that have reached the status of big data (BD). With recent developments in artificial intelligence (AI), theoretical and clinical breakthroughs could emerge. Analyses of large data sets with AI tools will allow the formulation of new testable hypotheses open new research avenues and provide innovative strategies for regulating immunity and treating immunological diseases. This includes diagnosis and …

Microbial Prevalence And Antibiotic Resistance Associated With Urban Food Production Systems, Nirosha Ruwani Amarasekara

Wayne State University Dissertations

Despite the increasing popularity of urban agriculture and farmers’ markets, there is a lack of scientific data on microbial prevalence and antibiotic resistance associated with this unique food production system. The overall goal of this research is to understand antibiotic resistance and microbial prevalence in soil and fresh produce associated with urban agriculture. Specifically, we aim to investigate ARG in association with resistance genes to metals and other compounds in urban agricultural soil as well as antibiotic resistome and Listeria contamination in fresh produce distributed in urban communities.

In the initial phase of this research, soil samples were collected from …

The Methane-Oxidizing Microbial Communities Of Three Maar Lakes In Tropical Monsoon Asia, Iona Eunice C. Bicaldo, Karol Sophia Agape R. Padilla, Tzu Hsuan Tu, Wan Ting Chen, Milette U. Mendoza-Pascual, Carmela Vannette B. Vicera, Justine R. De Leon, Kamille N. Poblete, Eleanor S. Austria, Mark Louie D. Lopez, Yuki Kobayashi, Fuh Kwo Shiah, Rey Donne S. Papa, Noboru Okuda, Pei Ling Wang, Li Hung Lin

Environmental Science Faculty Publications

Methane-oxidizing bacteria (MOB) is a group of planktonic microorganisms that use methane as their primary source of cellular energy. For tropical lakes in monsoon Asia, there is currently a knowledge gap on MOB community diversity and the factors influencing their abundance. Herewith, we present a preliminary assessment of the MOB communities in three maar lakes in tropical monsoon Asia using Catalyzed Reporter Deposition, Fluorescence In-Situ Hybridization (CARD-FISH), 16S rRNA amplicon sequencing, and pmoA gene sequencing. Correlation analysis between MOB abundances and lakes’ physicochemical parameters following seasonal monsoon events were performed to explain observed spatial and temporal patterns in MOB diversity. …

Managing Stress: A Study Of Stress Response Mechanisms In Mycobacteria, Augusto C. Hunt Serracin

Biology Dissertations - Archive

Mycobacteria encompass many pathogenic species known to cause severe disease in humans. A well-known example is Mycobacterium tuberculosis (Mtb), the causative agent of the lung disease tuberculosis, which kills millions of humans worldwide yearly. Pathogenic mycobacteria like Mtb are challenging to treat because of their innate ability to adapt to environmental stress. Their unique cell physiology and conserved stress responses allow them to combat biological insults, regulate growth, and regulate genes involved in stress; all these responses increase tolerance to antibiotics. The current therapies to treat mycobacterial infections are lengthy and, at times, unsuccessful, partly due to antibiotic tolerance. A …

A New Model For Polar Growth In Mycobacteria: The Role Of Wag31 And Mmpl3 In Cell Wall Synthesis, Neda Habibi Arejan

Biology Dissertations - Archive

The disease Tuberculosis (TB) is caused by the pathogen Mycobacterium tuberculosis and was the cause of over one million deaths worldwide in 2023 (World Health Organization, 2023). TB treatment is difficult due to antibiotic tolerance and emerging resistance in Mtb strains. Mycobacterial cells have different regulatory mechanisms that allow them to adjust to myriad environmental stressors: these responses often lead to antibiotic tolerance. Therefore, studying responses to stress will lead to insights about antibiotic tolerance and treatment failure. Here, we specifically study two essential mycobacterial proteins, Wag31 and MmpL3, involved in cell wall metabolism. We show that Wag31 has distinct …

Friends With Benefits: How Picking The Right Partner Pays Off, Patrick T. Stillson

Biology Dissertations - Archive

Animals are highly dependent on microbial symbionts for nutrient supplementation, parasite protection, toxin resistance, and more. While these microbes are important, these associations have the potential to shift from mutualistic to parasitic across environments and over time. Eight insect families from the hemipteran infraorder Pentatomomorpha have evolved a highly specialized relationship with bacteria in the genus Caballeronia. The symbiont is a free-living microbe, acquired from the environment each generation during early host development. By manipulating environmental conditions, I used the bug-Caballeronia model 1) to investigate whether symbionts with greater growth rates at high temperatures prevent hosts from experiencing …

Role Of Extracytoplasmic Function (Ecf) Sigma Factors In The Survival And Symbiosis Of Nitrogen-Fixing Bradyrhizobium Under Desiccation Stress And Comparative Analysis Of Desiccation-Tolerant Rhizobial Isolates, Mohammad Kamruzzaman

Biology Dissertations - Archive

Rhizobia are soil bacteria that facilitate biological nitrogen fixation (BNF) through a symbiotic relationship with legumes such as soybeans. As an eco-friendly alternative to chemical nitrogen fertilizers, rhizobial inoculants can enhance plant growth and yield. However, they face various stresses, including drought (i.e., desiccation). Rhizobia can manage desiccation stress by accumulating trehalose, a disaccharide produced by genes such as otsA, otsB, and treS. Extracytoplasmic function (ECF) sigma factors sense external signals and regulate these desiccation-related genes during the stress. Previous studies have highlighted the importance of EcfG in response to desiccation stress and symbiosis. Based on the protein sequence …

How Environmental Variation Affects Bumblebee Cognition And The Gut Microbiome, Parker Madison Campbell

Graduate Theses/Dissertations

This master's thesis examines the influence of environmental variables on cognitive processes in Bombus impatiens, focusing on the effects of ingested microbial communities on gut microbiota and their subsequent impact on associative color learning. The study implemented controlled feeding trials with isolated microbe species (Candida bombi, Metschnikowia reukaufii, Lactobacillus micheneri and a control with no microbes) to analyze shifts in gut microbial composition in foraging bees. Results indicated minor alterations in the microbial profiles of bees, yet no statistically significant correlation was found between these modifications and variations in learning or memory performance. Furthermore, the study assessed the impact of …

Antibiotic Resistance In A Coastal River In Mississippi, Usa – Potential Drivers, Shuo Shen, Wei Wu, Eric A. Saillant, Darrell Jay Grimes

Gulf and Caribbean Research

Wastewater treatment plants (WWTPs) are major sources of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in water bodies. Most studies on the impact of WWTPs on antibiotic resistance have focused on freshwater systems, with little information on coastal and estuarine waters with variable salinity. This study monitored seasonal levels of ARGs at the effluent and downstream of the Pascagoula— Moss Point WWTP in the lower Pascagoula River, a coastal river in southeastern Mississippi, USA. Surface water samples were collected seasonally at upstream, outflow, and 3 downstream sites from February to November 2016. Bacterial resistance to sulfamethazine, tetracycline, and …

Why Should Early-Career Scientists Publish In Society Journals, Stephen K. Dolan, Lori D. Banks, Wenqi Yu

Molecular Biosciences Faculty Publications

In this editorial, written by early-career scientists, we advocate for the invaluable role of society journals in our scientific community. By choosing to support these journals as authors, peer reviewers, and as editors, we can reinforce our academic growth and benefit from their re-investment back into the scientific ecosystem. Considering the numerous clear merits of this system for future generations of microbiologists and more broadly, society, we argue that early-career researchers should publish our high-quality research in society journals to shape the future of science and scientific publishing landscape.

The Inaugural Mbio Junior Editorial Board—Lessons Learned And The Path Forward Toward Improving The Peer Review Process, Cynthia Ayefoumi Adinortey, Stephen K. Dolan, Sarah Doore, Rebeccah Lijek, Diana Priscila Pires, Wenqi Yu, Elizabeth B. Draganova, Lennart Schada Von Borzyskowski

Molecular Biosciences Faculty Publications

The inaugural Junior Editorial Board (JEB) of mBio consisted of 64 early-career researchers active from 2022 to 2023. The goal of the JEB was to train early-career researchers in the art of peer review under the guidance of experienced editors. JEB members gained hands-on experience in peer review by participating in modules detailing the publishing process through the lenses of the journal, editor, and reviewer. Ultimately, JEB members applied this new knowledge by reviewing mBio manuscripts. Here, we summarize the background, the mission, and the achievements of the first mBio JEB. We also include possible trajectories for the future editions …

Revolutionizing Our Understanding Of Specific Platelet-Pathogen Interactions, Hammodah Rawhi Hammodah Alfar

Theses and Dissertations--Molecular and Cellular Biochemistry

Aside from their classical role in maintaining hemostasis, platelets are considered first-line vascular guardians that influence both the innate and adaptive immune systems. This is mediated by either direct interactions with immune cells or through the release of pre-stored cytokines and chemokines upon interacting with pathogens such as viruses. While this establishes platelets as potential players in the response to pathogens, it remains unclear what platelets can do with pathogens and how important that is to immune responses, especially against viruses. Most systemic viremias, such as HIV-1, present with mild thrombocytopenia, which is mediated through several mechanisms such as a …