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Full-Text Articles in Microbiology

Twenty Years Of Epithelial-Mesenchymal Transition: A State Of The Field From Temtia X, Pierre Savagner, Thomas Brabletz, Chonghui Cheng, Christine Gilles, Tian Hong, Myriam Polette, Guojun Sheng, Marc P Stemmler, Erik W Thompson Jan 2024

Twenty Years Of Epithelial-Mesenchymal Transition: A State Of The Field From Temtia X, Pierre Savagner, Thomas Brabletz, Chonghui Cheng, Christine Gilles, Tian Hong, Myriam Polette, Guojun Sheng, Marc P Stemmler, Erik W Thompson

Faculty, Staff and Students Publications

This report summarizes the 10th biennial meeting of The Epithelial Mesenchymal Transition International Association (TEMTIA), that took place in Paris on November 7-10, 2022. It provides a short but comprehensive introduction to the presentations and discussions that took place during the 3-day meeting. Similarly to previous TEMTIA meetings, TEMTIA X reviewed the most recent aspects of the epithelial-mesenchymal transition (EMT), a cellular process involved during distinct stages of development but also during wound healing and fibrosis to some degree. EMT has also been associated at various levels during tumor cell progression and metastasis. The meeting emphasized the intermediate stages of …


Select Gut Microbiota Impede Rotavirus Vaccine Efficacy, Vu L Ngo, Yanling Wang, Yadong Wang, Zhenda Shi, Robert Britton, Jun Zou, Sasirekha Ramani, Baoming Jiang, Andrew T Gewirtz Jan 2024

Select Gut Microbiota Impede Rotavirus Vaccine Efficacy, Vu L Ngo, Yanling Wang, Yadong Wang, Zhenda Shi, Robert Britton, Jun Zou, Sasirekha Ramani, Baoming Jiang, Andrew T Gewirtz

Faculty, Staff and Students Publications

BACKGROUND & AIMS: The protection provided by rotavirus (RV) vaccines is highly heterogeneous among individuals. We hypothesized that microbiota composition might influence RV vaccine efficacy.

METHODS: First, we examined the potential of segmented filamentous bacteria (SFB) colonization to influence RV vaccine efficacy in mice. Next, we probed the influence of human microbiomes on RV vaccination via administering mice fecal microbial transplants (FMTs) from children with robust or minimal RV vaccine responsiveness. Post-FMT, mice were subjected to RV vaccination followed by RV challenge.

RESULTS: SFB colonization induced a phenotype that was reminiscent of RV vaccine failure (ie, failure to generate RV …


Mfgm-Enriched Whey Displays Antiviral Activity Against Common Pediatric Viruses, Evelien Kramer, Ketki Patil, Vassilis Triantis, Jan A H Bastiaans, Michela Mazzon, Sasirekha Ramani, Tim T Lambers Jan 2024

Mfgm-Enriched Whey Displays Antiviral Activity Against Common Pediatric Viruses, Evelien Kramer, Ketki Patil, Vassilis Triantis, Jan A H Bastiaans, Michela Mazzon, Sasirekha Ramani, Tim T Lambers

Faculty, Staff and Students Publications

BACKGROUND: Among the most common mucosal viral infections in infants are rotavirus, one of the main causes of severe gastroenteritis in infants and children up to 5 years, and respiratory syncytial virus (RSV), one of the leading causes of lower respiratory tract infections. Both human milk and bovine milk derived factors may provide protection against mucosal viral infections. More recently, a similar activity of milk derived proteins was suggested for SARS-CoV-2. The goal of the current study was to test antiviral activity of the bovine milkfat globule membrane (MFGM) against rotavirus, RSV and SARS-CoV-2 and to further characterize MFGM-enriched whey …


Age-Associated Temporal Decline In Butyrate-Producing Bacteria Plays A Key Pathogenic Role In The Onset And Progression Of Neuropathology And Memory Deficits In 3×Tg-Ad Mice, Paula M Chilton, Smita S Ghare, Benjamin T Charpentier, Scott A Myers, Aakarsha V Rao, Joseph F Petrosino, Kristi L Hoffman, John C Greenwell, Neetu Tyagi, Jyotirmaya Behera, Yali Wang, Lucy J Sloan, Jingwen Zhang, Christopher B Shields, Gregory E Cooper, Leila Gobejishvili, Scott R Whittemore, Craig J Mcclain, Shirish S Barve Jan 2024

Age-Associated Temporal Decline In Butyrate-Producing Bacteria Plays A Key Pathogenic Role In The Onset And Progression Of Neuropathology And Memory Deficits In 3×Tg-Ad Mice, Paula M Chilton, Smita S Ghare, Benjamin T Charpentier, Scott A Myers, Aakarsha V Rao, Joseph F Petrosino, Kristi L Hoffman, John C Greenwell, Neetu Tyagi, Jyotirmaya Behera, Yali Wang, Lucy J Sloan, Jingwen Zhang, Christopher B Shields, Gregory E Cooper, Leila Gobejishvili, Scott R Whittemore, Craig J Mcclain, Shirish S Barve

Faculty, Staff and Students Publications

Alterations in the gut-microbiome-brain axis are increasingly being recognized to be involved in Alzheimer's disease (AD) pathogenesis. However, the functional consequences of enteric dysbiosis linking gut microbiota and brain pathology in AD progression remain largely undetermined. The present work investigated the causal role of age-associated temporal decline in butyrate-producing bacteria and butyrate in the etiopathogenesis of AD. Longitudinal metagenomics, neuropathological, and memory analyses were performed in the 3×Tg-AD mouse model. Metataxonomic analyses showed a significant temporal decline in the alpha diversity marked by a decrease in butyrate-producing bacterial communities and a concurrent reduction in cecal butyrate production. Inferred metagenomics analysis …


Inter And Intra-Host Diversity Of Rsv In Hematopoietic Stem Cell Transplant Adults With Normal And Delayed Viral Clearance, Vasanthi Avadhanula, Daniel Paiva Agustinho, Vipin Kumar Menon, Roy F Chemaly, Dimpy P Shah, Xiang Qin, Anil Surathu, Harshavardhan Doddapaneni, Donna M Muzny, Ginger A Metcalf, Sara Javornik Cregeen, Richard A Gibbs, Joseph F Petrosino, Fritz J Sedlazeck, Pedro A Piedra Jan 2024

Inter And Intra-Host Diversity Of Rsv In Hematopoietic Stem Cell Transplant Adults With Normal And Delayed Viral Clearance, Vasanthi Avadhanula, Daniel Paiva Agustinho, Vipin Kumar Menon, Roy F Chemaly, Dimpy P Shah, Xiang Qin, Anil Surathu, Harshavardhan Doddapaneni, Donna M Muzny, Ginger A Metcalf, Sara Javornik Cregeen, Richard A Gibbs, Joseph F Petrosino, Fritz J Sedlazeck, Pedro A Piedra

Faculty, Staff and Students Publications

Respiratory syncytial virus (RSV) infection in immunocompromised individuals often leads to prolonged illness, progression to severe lower respiratory tract infection, and even death. How the host immune environment of the hematopoietic stem cell transplant (HCT) adults can affect viral genetic variation during an acute infection is not understood well. In the present study, we performed whole genome sequencing of RSV/A or RSV/B from samples collected longitudinally from HCT adults with normal (<14 >days) and delayed (≥14 days) RSV clearance who were enrolled in a ribavirin trial. We determined the inter-host and intra-host genetic variation of RSV and the effect of …


Vaccines Against Extraintestinal Pathogenic Escherichia Coli (Expec): Progress And Challenges, Ling Qiu, Dylan Chirman, Justin R Clark, Yikun Xing, Haroldo Hernandez Santos, Ellen E Vaughan, Anthony W Maresso Jan 2024

Vaccines Against Extraintestinal Pathogenic Escherichia Coli (Expec): Progress And Challenges, Ling Qiu, Dylan Chirman, Justin R Clark, Yikun Xing, Haroldo Hernandez Santos, Ellen E Vaughan, Anthony W Maresso

Faculty, Staff and Students Publications

The emergence of antimicrobial resistance (AMR) is a principal global health crisis projected to cause 10 million deaths annually worldwide by 2050. While the Gram-negative bacteria Escherichia coli is commonly found as a commensal microbe in the human gut, some strains are dangerously pathogenic, contributing to the highest AMR-associated mortality. Strains of E. coli that can translocate from the gastrointestinal tract to distal sites, called extraintestinal E. coli (ExPEC), are particularly problematic and predominantly afflict women, the elderly, and immunocompromised populations. Despite nearly 40 years of clinical trials, there is still no vaccine against ExPEC. One reason for this is …


Factors Associated With Hepatitis C-Related Hospitalizations And Inpatient Mortality In The United States, Pre- And Post-Onset Of The Covid-19 Pandemic, Christina R. Samuel Jan 2024

Factors Associated With Hepatitis C-Related Hospitalizations And Inpatient Mortality In The United States, Pre- And Post-Onset Of The Covid-19 Pandemic, Christina R. Samuel

College of Graduate Studies: Theses & Dissertations

Background: Hepatitis C is a significant public health problem in the United States and imposes a substantial burden on the healthcare system. Previous research shows that the COVID-19 pandemic response efforts have overshadowed hepatitis C testing and treatment measures in health care settings across the country. The purpose of this study was to describe and examine the factors associated with hepatitis C-related hospitalizations and inpatient mortality in the United States, pre- and post-onset of the COVID-19 pandemic. Methods: Data were obtained from the 2019-2020 National Inpatient Sample database. The study population included persons aged ≥18 years with hepatitis C-related inpatient …


Temporal Distribution Of Potential Waterborne Pathogens In Sequiota Spring, William J. Durstock Jan 2024

Temporal Distribution Of Potential Waterborne Pathogens In Sequiota Spring, William J. Durstock

Graduate Theses/Dissertations

Waterborne pathogens from human fecal matter pose a significant health risk in karst environments, where domestic wastewater can easily be transferred to the shallow groundwater system via old, leaky septic tanks and damaged sewer lines. This study monitored fecal indicator bacteria (FIB) and potential pathogens in Sequiota Spring located in the karst region of southwest Missouri, using Microbial Source Tracking (MST) and Illumina DNA sequencing of bacterial 16S rRNA genes. MST identified high levels of human fecal indicator bacteria (HFIB) (up to 110,000 cells/L) in July 2020. By June 2022, HFIB levels had dropped significantly (55-fold reduction) after the City …


Effects Of Subchronic Oral Pfos Exposure Via Drinking Water On Gut Microbiota Composition, Emma Ann Loder Jan 2024

Effects Of Subchronic Oral Pfos Exposure Via Drinking Water On Gut Microbiota Composition, Emma Ann Loder

Graduate Theses/Dissertations

Perfluorooctanesulfonic acid (PFOS) has been phased out of production in the United States, but because of its resistance to degradation and its persistence in the environment, PFOS can be found in drinking water across America. Oral exposure to PFOS has been linked to adverse developmental, immunological, hepatic, and endocrine health. Oral PFOS exposure may alter the gut microbiota and cause dysbiosis, which is implicated in the pathology of inflammatory diseases like Crohn’s disease, diabetes, and ulcerative colitis. The goal of the study was to investigate the effects of subchronic oral PFOS exposure on the composition of the gut microbiota. Adult …


Patterns Of Epiphytic Bacterial Growth On Flower Surfaces: Relationships With Flower Longevity And Environmental Factors, Rita Nkem Afagwu Jan 2024

Patterns Of Epiphytic Bacterial Growth On Flower Surfaces: Relationships With Flower Longevity And Environmental Factors, Rita Nkem Afagwu

Graduate Theses/Dissertations

Flowers host diverse communities of epiphytic bacteria, which can impact floral functions, pollinator interactions, and overall plant fitness. However, little is known about how the abundance of these bacteria change as flowers age, and how these shifts may correlate with floral longevity. In this study I investigate the change in bacterial abundance across the lifespan of a flower from anthesis (opening of bud to flower) to senescence (wilting of flower) and to explore the potential implications for floral longevity. We tracked the age of the flowers by determining the average age to senescence in flowers of 8 plant species over …


How Environmental Variation Affects Bumblebee Cognition And The Gut Microbiome, Parker Madison Campbell Jan 2024

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 …


Competition Between Bradyrhizobium Strains For Soybean Nodulation, Lilia Ernestina Montanez Hernandez Jan 2024

Competition Between Bradyrhizobium Strains For Soybean Nodulation, Lilia Ernestina Montanez Hernandez

Electronic Theses and Dissertations

Biological Nitrogen Fixation (BNF) has surged as a natural strategy to provide available nitrogen to crops by taking advantage of diazotrophs, microorganisms that can reduce atmospheric nitrogen to ammonia. Soybean, a major crop, greatly benefits from BNF by forming endosymbiotic relationships with rhizobacteria from the genus Bradyrhizobium, which culminates in the formation of specialized organs called nodules, where nitrogen fixation occurs. This is known as Symbiotic Nitrogen Fixation (SNF). Inoculation of soybean fields with high nitrogen fixing Bradyrhizobium strains to stimulate SNF is being used as a strategy to increase crop productivity and nitrogen content. However, in North America, SNF …


Genetic Engineering Of Escherichia Coli For The Production Of Riboflavin, Adeyemi Adesanwo Jan 2024

Genetic Engineering Of Escherichia Coli For The Production Of Riboflavin, Adeyemi Adesanwo

Graduate Research Theses & Dissertations

Riboflavin, a water-soluble vitamin B2, is essential for the growth and reproduction of living organisms. However, humans and animals lack a riboflavin synthesis pathway and must rely on diets derived from plants and microbes for this essential vitamin. To meet our needs for vitamin B2, industrial riboflavin production is currently being pursued using strains of Bacillus subtilis. The fermentation process is successful, but improvements are needed for better substrate-to-product conversion yield. To this end, it is imperative to develop alternative microbial strains for cost-effective riboflavin production.

Due to its simple growth requirement, well-understood genetic background, and widely available genetic tools, …


Understanding Cellular Dynamics: Investigating A Yeast-Two Hybrid Protein-Protein Interaction, Riok3:Cse1l; Also By Investigating Trogocytosis Of Cd4+ T Cells From Rhog-/- Mice, Brittnee N. Crane Jan 2024

Understanding Cellular Dynamics: Investigating A Yeast-Two Hybrid Protein-Protein Interaction, Riok3:Cse1l; Also By Investigating Trogocytosis Of Cd4+ T Cells From Rhog-/- Mice, Brittnee N. Crane

Graduate Student Theses, Dissertations, & Professional Papers

Rift Valley fever virus (RVFV) is a negative-sense virus that was first described in 1930 when it was isolated from sheep during an outbreak. In the last 25 years there has been a spread in the geographical range into the Middle East. The most susceptible animals are cattle, goats, sheep, and camels. The most overt symptom of livestock infection is that infected pregnant animals experience spontaneous abortion. Humans are susceptible as well and symptoms range from mild febrile illness to liver necrosis, blindness, hemorrhagic fever, and death. An important player in the cellular innate response to RVFV infections is the …


Investigating Birds As Dispersal Vectors Of Litylenchus Crenatae Subsp. Mccannii (Anguinidae), The Nematode Associated With Beech Leaf Disease, Spencer Rock Parkinson Jan 2024

Investigating Birds As Dispersal Vectors Of Litylenchus Crenatae Subsp. Mccannii (Anguinidae), The Nematode Associated With Beech Leaf Disease, Spencer Rock Parkinson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Beech leaf disease (BLD) is an emerging forest pathogen primarily affecting American beech (Fagus grandifolia, Ehrh.) in North America and has been attributed to tree mortality of sapling sized trees within five to seven years of infection. Symptoms typically occur in regenerating American beech thickets sprouting from roots of trees killed by beech bark disease. Scientists first observed BLD in Ohio in 2012 and currently has spread to 15 states in the USA and one Canadian province. The nematode Litylenchus crenatae subsp. mccannii (Lcm) is highly associated with BLD symptoms, interveinal chlorosis and defoliation of leaves, and is currently …


Characterization Of Host Cell Specific Interactions During Spotted Fever Group Rickettsiae Infection, Emerson Towey Jan 2024

Characterization Of Host Cell Specific Interactions During Spotted Fever Group Rickettsiae Infection, Emerson Towey

Graduate Theses, Dissertations, and Problem Reports (ETD)

Vector-borne diseases have been increasing over the past few years due to changes in climate and disturbances in the vectors’ natural environment. To mitigate the risks of these diseases, it is necessary to understand pathogen biology and how it interacts with a host to cause disease. Here we focus our attention on the tick-borne pathogen, Rickettsia rickettsii. R. rickettsii is a member of the spotted fever group (SFG) Rickettsiae and is the etiological agent of Rocky Mountain spotted fever (RMSF), a fatal human disease that is lacking an effective vaccine. Members of the bacterial genus Rickettsia are obligate intracellular endoparasites …


The Sewage Microbiome Dynamics Of Different Serving Neighborhoods In Charleston, Illinois, Sandra Chiamaka Okoye Jan 2024

The Sewage Microbiome Dynamics Of Different Serving Neighborhoods In Charleston, Illinois, Sandra Chiamaka Okoye

Masters Theses

The complex microbial ecosystem within sewage systems holds significant implications for environmental and public health. Unlike studies on wastewater treatment plant microbiomes, upstream sewage systems have not been studied widely. This research investigated the dynamic sewage microbiome across diverse serving neighborhoods in Charleston, Illinois, encompassing residential, hospital, industrial, and university areas. Drawing upon recent advancements in microbiome research, the study aimed to unravel the spatial and temporal variations in microbial structures. Three times between June to December 2023 sewage samples were collected from manholes in the areas mentioned above. Community DNA was extracted and sequenced for the V4-V5 region of …


Causal Association Between Gut Microbiomes And Different Types Of Aneurysms: A Mendelian Randomization Study, Youjia Qiu, Yucheng Hou, Xingzhou Wei, Menghan Wang, Ziqian Yin, Minjia Xie, Aojie Duan, Chao Ma, Ke Si, Zhong Wang Jan 2024

Causal Association Between Gut Microbiomes And Different Types Of Aneurysms: A Mendelian Randomization Study, Youjia Qiu, Yucheng Hou, Xingzhou Wei, Menghan Wang, Ziqian Yin, Minjia Xie, Aojie Duan, Chao Ma, Ke Si, Zhong Wang

Faculty, Staff and Student Publications

BACKGROUND: Previous studies suggests that gut microbiomes are associated with the formation and progression of aneurysms. However, the causal association between them remains unclear.

METHODS: A two-sample Mendelian randomization was conducted to investigate whether gut microbiomes have a causal effect on the risk of intracerebral aneurysm (IA), thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA), and aortic aneurysm (AA). Single nucleotide polymorphisms (SNPs) smaller than the locus-wide significance level (1 × 10

RESULTS: The phylum

CONCLUSION: Our MR analysis confirmed the causal association of specific gut microbiomes with AAA, and these microbiomes were considered as protective factors. Our result …


The Role Of Osaa Gene In Aspergillus Fumigatus Development, Secondary Metabolism And Virulence., Apoorva Dabholkar Jan 2024

The Role Of Osaa Gene In Aspergillus Fumigatus Development, Secondary Metabolism And Virulence., Apoorva Dabholkar

Graduate Research Theses & Dissertations

Aspergillus fumigatus is the leading cause of aspergillosis, associated with high mortality rates, particularly in immunocompromised individuals. In search of novel genetic targets against aspergillosis, we studied the WOPR transcription factor OsaA. Deletion of the osaA gene resulted in colony growth reduction. Conidiation is also influenced by osaA; both osaA deletion and overexpression resulted in a decrease in spore production. Wild-type expression levels of osaA are necessary for expression of the conidiation regulatory genes brlA, abaA and wetA. In addition, osaA is necessary for normal cell wall integrity. Furthermore, deletion of osaA resulted in a reduction in the ability of …


Ascertaining A Biochemical Approach To Chlorophyll D Biosynthesis In Acaryochloris Spp., Rashmi Shivni Jan 2024

Ascertaining A Biochemical Approach To Chlorophyll D Biosynthesis In Acaryochloris Spp., Rashmi Shivni

Graduate Research Theses & Dissertations

Photosynthesis is one of the most abundant metabolic systems on Earth, and specifically, oxygenic photosynthesis primed the planet for complex, multicellular life. The hallmark of modern oxygenic photosynthesis is the photopigment chlorophyll a found in nearly all oxygenic phototrophs as their primary photopigment in their photosynthesis pathways. There are also many organisms that tap into a variety of chlorophylls to extend the energetic limits of photosynthesis, which are largely found as accessory pigments. One genus of cyanobacteria, Acaryochloris, has garnered attention for the ability to undergo photosynthesis by harnessing the far-red part of the visible light spectrum using chlorophyll d …


Molecular Investigation Of Tick-Borne Pathogens In Feral Swine (Sus Scrofa) From Seven Us States, Sofiane Aiche Jan 2024

Molecular Investigation Of Tick-Borne Pathogens In Feral Swine (Sus Scrofa) From Seven Us States, Sofiane Aiche

Masters Theses

Feral swine (Sus scrofa) have been proposed as part of the lifecycles of multiple tickborne pathogens (TBP). This is a result of the increase in feral swine populations and increased tick populations and geographic ranges. Few surveys exist on the TBP relevant to human and wildlife of feral swine in the US. The aim of this study is to investigate the prevalence of 10 TBP: Anaplasma spp., Borrelia spp., Cytauxzoon felis, Hepatozoon spp., Babesia spp., Mycoplasma spp., Trypanosoma cruzi, Toxoplasma gondii, Yersinia pestis, and Rickettsia spp. A total of 87 feral swine blood samples …


Sars-Cov-2 Immunogenicity Models Inform Novel Strategies That Can Improve Mrna Vaccines, Katherine S. Lee Jan 2024

Sars-Cov-2 Immunogenicity Models Inform Novel Strategies That Can Improve Mrna Vaccines, Katherine S. Lee

Graduate Theses, Dissertations, and Problem Reports (ETD)

The onset of the 2020 COVID-19 pandemic, caused by the novel coronavirus SARS-CoV-2, issued a call to action in the fields of biomedical science and public health to implement strategies to contain and protect against the viral threat. In record times, pharmaceutical companies produced antiviral therapies and novel mRNA vaccines that were approved by the FDA for human use. With time, these vaccines were able to assist in ending the pandemic. However, time also showed the limits of mRNA vaccine induced immunity. Despite antibody responses being initially robust, titers dramatically wane with time and are limited in cross-neutralizing ability. As …


Leveraging Bioinformatics To Understand Chlorophyll D Biosynthesis In Acaryochloris Spp., Dikshyant Gautam Jan 2024

Leveraging Bioinformatics To Understand Chlorophyll D Biosynthesis In Acaryochloris Spp., Dikshyant Gautam

Graduate Research Theses & Dissertations

Acaryochloris strains can adapt into far red region of the visible spectrum by utilizing its unique chlorophyll called chlorophyll d (Chl d). The genetic machinery behind Chl d has not been discovered yet. Biosynthetic pathway for other chlorophylls like chlorophyll a, chlorophyll b and chlorophyll f found in cyanobacteria are however well known. This research aims to understand the biosynthetic pathway responsible for chlorophyll d production. Bioinformatics approaches like comparative genomics, machine learning, and weighted gene co-expression network analysis (WGCNA) were central in this study to identify candidate genes and regulatory mechanisms potentially involved in chlorophyll d synthesis.

An important …


Dust-Driven Mechanism For Marine Particle Aggregation: Interactions Between Clay Minerals, Heterotrophic Bacteria And Organic Matter Influences Aggregation In Marine Systems, Vignesh Gokuladas Menon Jan 2024

Dust-Driven Mechanism For Marine Particle Aggregation: Interactions Between Clay Minerals, Heterotrophic Bacteria And Organic Matter Influences Aggregation In Marine Systems, Vignesh Gokuladas Menon

Dartmouth College Master’s Theses

Atmospheric dust deposition plays a crucial role in marine biogeochemical cycles, yet mechanisms underlying its impact on particle dynamics remain unclear. This study investigates the synergistic interactions between marine heterotrophic bacteria and clay minerals in seawater, focusing on their effect on Transparent Exopolymer Particles (TEP) production and organoclay aggregation. Field experiments in the Gulf of Maine and laboratory roller tank studies were conducted using natural microbial communities and model heterotrophic bacterial strains (Alteromonas sp. EZ55, Marinobacter adhaerens HP15, and Sulfitobacter sp. NAS-14.1). Results demonstrate that clay exposure significantly enhances TEP production by bloom-associated heterotrophic bacteria, with increases up to …


Tetrodotoxin, Fungal Pathogen Infection, And Bacterial Microbiome Associations Are Variable In The Skin Microecosystems Of Two Taricha Newt Species, Talon B. Jost Jan 2024

Tetrodotoxin, Fungal Pathogen Infection, And Bacterial Microbiome Associations Are Variable In The Skin Microecosystems Of Two Taricha Newt Species, Talon B. Jost

EWU Masters Thesis Collection

Chytridiomycosis is an amphibian disease linked to population declines and species extinctions, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). While chytridiomycosis can result in host death, some amphibians are less susceptible to severe infections through intrinsic factors including host-associated skin microbes aiding defense through resource competition and antifungal metabolite production. Amphibians can also release toxins in response to stress cues to defend against disease, parasitism, and predation. Tetrodotoxin (TTX) is a potent low molecular weight neurotoxin found in genus Taricha, and despite a previously observed negative relationship between differential levels of TTX concentration and Bd infection presence within a …


Investigating The Role And Mechanism Of Host Cell Death In Porcine Reproductive And Respiratory Virus Infection, Michelle Steyn Jan 2024

Investigating The Role And Mechanism Of Host Cell Death In Porcine Reproductive And Respiratory Virus Infection, Michelle Steyn

Electronic Theses and Dissertations

No abstract provided.


Ecophysiology Of Bradyrhizobium Diazoefficiens Usda 110, Armaan Kaur Sandhu Jan 2024

Ecophysiology Of Bradyrhizobium Diazoefficiens Usda 110, Armaan Kaur Sandhu

Electronic Theses and Dissertations

With increasing demand for soybean, maximizing plant yield is important yiel is dependent on nitrogen availability, but nitrogen fertilizers can meet the plant's needs but have severe environmental impacts. An economically and environmentally sustainable approach is to enhance nitrogen availability through Biological Nitrogen Fixation by symbiotic rhizobia, Bradyrhizobium, an efficient nitrogen fixer for soybean. This symbiosis begins with attachment of rhizobia to legume roots. Root and rhizobia surface properties play a significant role in this attachment. Another major factor affecting root colonization is bacterial competition ability. There is a lack of knowledge on the role of bacterial surface properties, competition …


Scale And Habitat Effects On Measurement Of Streptomyces Biogeography And Biodiversity, Terilyn A. Stoflet Jan 2024

Scale And Habitat Effects On Measurement Of Streptomyces Biogeography And Biodiversity, Terilyn A. Stoflet

Cal Poly Humboldt theses and projects

Bacteria in the genus Streptomyces are detected in most soils around the world, as well as on and in seeds, plants, animals, insects and the wind. Currently, more than 700 valid species of Streptomyces have been identified worldwide. Streptomyces produce the majority of antibiotics, antivirals and antifungals, as well as important agricultural bioactive molecules due to their unique genetic capabilities. Their distinct genetic abilities allow them to produce an unlimited amount of biosynthetic gene clusters, or BGC’s. Although many compounds come from Streptomyces, scientists have not discovered the biogeographic patterns of this genus. The biogeography of Streptomyces is a …


Host-Defense Piscidin Peptides As Antibiotic Adjuvants Against Clostridioides Difficile, Adenrele Oludiran, Areej Malik, Andriana C. Zourou, Yonghan Wu, Steven P. Gross, Albert Siryapon, Asia Poudel, Kwincy Alleyne, Savion Adams, David S. Courson, Myriam L. Cotten, Erin B. Purcell Jan 2024

Host-Defense Piscidin Peptides As Antibiotic Adjuvants Against Clostridioides Difficile, Adenrele Oludiran, Areej Malik, Andriana C. Zourou, Yonghan Wu, Steven P. Gross, Albert Siryapon, Asia Poudel, Kwincy Alleyne, Savion Adams, David S. Courson, Myriam L. Cotten, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The spore-forming intestinal pathogen Clostridioides difficile causes multidrug resistant infection with a high rate of recurrence after treatment. Piscidins 1 (p1) and 3 (p3), cationic host defense peptides with micromolar cytotoxicity against C. difficile, sensitize C. difficile to clinically relevant antibiotics tested at sublethal concentrations. Both peptides bind to Cu2+ using an amino terminal copper and nickel binding motif. Here, we investigate the two peptides in the apo and holo states as antibiotic adjuvants against an epidemic strain of C. difficile. We find that the presence of the peptides leads to lower doses of …


Investigation Of L-Serine Synthesis And Transport As Stabilizing Feedback Mechanisms Within The Tsetse-Wigglesworthia Symbiosis, Ryan Phillips Jan 2024

Investigation Of L-Serine Synthesis And Transport As Stabilizing Feedback Mechanisms Within The Tsetse-Wigglesworthia Symbiosis, Ryan Phillips

Graduate Theses, Dissertations, and Problem Reports (ETD)

Tsetse flies (Glossina morsitans), which are the obligate vectors of Old-World trypanosomes (Trypanosoma spp.) that cause African trypanosomiasis, have a bacteriome that houses the intracellular endosymbiont Wigglesworthia glossinidia. The ancient coevolution of these species has led to the integration of Wigglesworthia metabolism into tsetse physiology and a subsequent reliance on nutrient exchange for maintaining the fitness of both partners. The establishment of this obligate mutualism has facilitated the emergence of feedback mechanisms that stabilize the symbiosis, such as that which involves the exchange of L-serine and B vitamins. The Gammaproteobacteria Wigglesworthia supplement B vitamins lacking …