Microbiology Commons^™

Characterization And Fluorescence Of Yellow Biofilms In Karst Caves, Southwest Slovenia, Janez Mulec, Andreea Oarga-Mulec, Rok Tomazin, Tadeja Matos

International Journal of Speleology

Biofilms of different colours that colonize surfaces within karst caves represent a source of nutrients. They occur commonly and abundantly at sites with sediments, and close to seepages or underground rivers. Golden-yellow subaerial biofilms are particularly well observed because of their contrast with their surroundings, the characteristics of the pigment and recently, even more, due to the characteristics of light-emitting diode (LED) illumination. Yellow microbial biofilms were sampled from three caves in southwestern Slovenia, Dimnice, Križna jama and Sveta jama. The highest concentration of cultivable microbes (2.33×10⁸ CFU/g) and the biggest number of identified bacteria (66.0%) were retrieved from …

Tonb Not Directly Related To Efflux Of Antibiotics In E. Coli, Amber Gombash

Honors Projects

Studies in Pseudomonas aeruginosa have suggested that the TonB energy transduction system directly contributes to efflux-mediated antibiotic resistance, ostensibly by energizing one or more efflux systems. We have found ∆tonB strains of Escherichia coli to similarly be more sensitive to certain antibiotics relative to wild-type strains. To test the hypothesis that this enhanced sensitivity involved the energization of efflux systems, sensitivity patterns for a variety of antibiotics were evaluated using a set of strains differentially lacking genes encoding the Acr efflux system, the universal outer membrane efflux portal TolC, and TonB. No correlation was evident between the resistance phenotypes of …

A Synthetic Lethal Screen Identifies A Role For Lin-44/Wnt In C.Elegans Embryogenesis, Samanth N. Hartin, Martin L. Hudson, Curtis Yingling, Brian D. Ackley

Faculty Articles

Background The C. elegans proteins PTP-3/LAR-RPTP and SDN-1/Syndecan are conserved cell adhesion molecules. Loss-of-function (LOF) mutations in either ptp-3 or sdn-1 result in low penetrance embryonic developmental defects. Work from other systems has shown that syndecans can function as ligands for LAR receptors in vivo. We used double mutant analysis to test whether ptp-3 and sdn-1 function in a linear genetic pathway during C. elegans embryogenesis. Results We found animals with LOF in both sdn-1 and ptp-3 exhibited a highly penetrant synthetic lethality (SynLet), with only a small percentage of animals surviving to adulthood. Analysis of the survivors demonstrated that …

Section Abstracts: Biology With Microbiology And Molecular Biology

Virginia Journal of Science

Abstracts of the Biology with Microbiology and Molecular Biology Section for the 93rd Annual Meeting of the Virginia Academy of Science, May 21-23, 2015, James Madison University, Richmond, Virginia

Combating Infectious Diseases In Aquaculture With An Original Probiotic Product, Meagan Hamblin, Saebom Sohn, Christine Ahn Dao, Marta Gomez-Chiarri, David R. Nelson, David Worthen, David Rowley

Senior Honors Projects

Oyster production in Rhode Island accounts for over $2.5 million in annual revenue, making it the top aquaculture product in the state. However, larval tank infections significantly constrain production and create substantial economic losses for commercial hatcheries. In most cases antibiotics may not be used to prevent or treat larval tank infections. A probiotic, or beneficial microbe which competes with pathogens, is a safer and “green” approach to preventing infections. Vibriosis, a common cause of oyster larval mortality, is the result of Vibrio species infections. Previous studies have shown that a native Rhode Island microbe, Bacillus pumilus RI06-95, protects oyster …

Stressed Induced Changes In Karenia Brevis Ribosomal Rna, David Scott Jayroe

Master's Theses

Karenia brevis is a toxic marine dinoflagellate that causes harmful algal blooms (HABs), also known as red tides, in the Gulf of Mexico. These blooms are responsible for massive fish kills, shellfish bed contaminations, adverse human health effects, and vast economic loss. For these reasons, extensive research has gone into understanding the mechanisms and dynamics of bloom behavior by studying K. brevis in the field and in the lab. In order to understand higher order bloom behavior and dynamics it is imperative to understand K. brevis at the cellular level. In growing K. brevis in vitro under a variety of …

Epiphytic Diatom Community Structure In A Karst Riverine System, Gregory John Barren

Masters Theses & Specialist Projects

The goal of this study was to assess the epiphytic diatom community structure of two host species along a karst gradient in the upper Green River, Kentucky to a gain a better understanding of the role of diatoms in the food web. The host species studied were Podostemum ceratophyllum and Cladophora. Percent cover of P. ceratophyllum and Cladophora were quantified in the four study reaches. The host species were sampled near-shore and mid-channel in each reach in September and October of 2013. After diatoms were extracted from the host and enumerated the density and diversity were quantified. Twelve genera were …

Evolution Of Sperm Activation In Nematodes, Qing Wei

Graduate School of Biomedical Sciences Theses and Dissertations

Three hermaphroditic species in the nematode genus Caenorhabditis - C. elegans, C. briggsae and C. tropicalis evolved independently from a male/female ancestor. Thus, the hermaphroditic reproductive system provides an ideal subject for studying the origin of new complex traits. Previous studies implied that this transition required two steps: a mutation that caused XY animals to make sperm, and a mutation that allowed XX spermatids to activate and fertilize oocytes. In this dissertation, I show how sperm activation is regulated in different hermaphroditic species.

First, I used TALENs to create genetic tools for C. briggsae and C. tropicalis. These tools were …

The Effects Of Diet And The Microbiome On Reproduction And Longevity: A Comparative Review Across 5 Continents, Stephanie N. Chilton, Megan K. Enos, Jeremy P. Burton, Gregor Reid

Microbiology & Immunology Publications

Human longevity and quality of life remain key societal drivers, but the healthcare burden of diet-related chronic diseases is economically unmanageable. In recent years, it has been proposed that the composition and abundance profiles of certain bacterial phyla in the gut are indicators of malnutrition, and ill health. But, how much does the gut microbiome and diet really contribute to outcomes? The description of three microbial enterotypes remains to be verified, as does its significance for health tested across continents and within people who migrate from one lifestyle to another. It is not simply that the diet of one region …

How Probiotics And The Microbiome Will Change Medical Practice, Gregor Reid

Microbiology & Immunology Publications

No abstract provided.

Influence Of The Anti-Hiv Drug Elvitegravir On Chlamydial Development And The Characterization Of Chlamydial Polymorphic Membrane Protein Expression In Herpes Simplex Virus (Hsv)/C. Trachomatis Co-Infected Cells, Hena Yakoob

Undergraduate Honors Theses

Chlamydia trachomatis is the most common bacterial agent of sexually transmitted infections worldwide and a common co-infection in AIDS patients. Chlamydial genital tract infections are often asymptomatic; therefore many infections go untreated and result in complications like chronic inflammation, ectopic pregnancy, and pelvic inflammatory disease. Chlamydia share a unique developmental cycle and under stress, can enter a state known as persistence, in which the bacteria are noninfectious but still viable. Removal of the stressor allows the chlamydiae to re-enter and complete the developmental cycle. Exposure to low-dose quinolones can cause the chlamydiae to enter persistence and halt the developmental cycle. …

The Effects Of Lotion Fatty Acids On Gram Negative Skin Flora: Implications For Membrane Remodeling And Pathogenicity, Adrianna Eder

Honors Theses

AIM: The purpose of this experiment was to determine whether or not Enterobacter aerogenes, Acinetobacter baumannii, and Klebsiella pneumoniae, which are three gram negative bacteria commonly found on the skin, utilize fatty acids in a manner that affects bacterial phenotype. Furthermore, an objective was to gain a deeper understanding of how the alteration of bacterial membranes, as a result of fatty acid uptake, affected the pathogenicity, membrane permeability, and resistance in gram negative bacteria. METHODS: The lipids were extracted using the method of Bligh and Dyer and analyzed using thin-layer chromatography (TLC). A series of tests were performed, including a …

Exploring The Oncolytic Potentail Of A Double Knock-Out Tanapoxvirus Containing Flic Transgene, Esaw W. Kurban

Masters Theses

Since the emergence of oncolytic viruses (OVs), OVs have seen success in clinical trials and are a vital alternative treatment for cancer. Colorectal cancers are diseases which cause substantial health issues in the developed world, but current invasive treatment methods do not perform well in patients with advanced disease. We have explored the potential of tanapoxvirus (TPV) for its oncolytic virothrapy in two manners; specific gene deletion and non-targeted gene deletion. The non-targeted mutation of TPV’s genome was attempted using N-methyl-N-nitro-N-nitrosoguanidine (NTG) and N-ethyl-N-nitrosourea (ENU) as alkylating chemical. Specific gene deletion involved knocking-out a thymidine kinase gene (TPV-66R) and a …

Identification Of Transcription Factors Gzf3, Rfx1, Orf19.3928 As Being Implicated In Candida-Bacterial Interactions., Joni Watson

Undergraduate Honors Theses

Candida albicans is an opportunistic pathogen that is present in the normal flora in a majority of individuals. One key factor in C. albicans virulence is the ability to change its morphology from yeast to an elongated or hyphal form. The regulation of this morphogenesis relies in part upon quorum sensing (QS) molecules. C. albicans often exists as part of a mixed culture alongside other microbes and is influenced by their presence as well as the presence of QS molecules that they produce. In this study, a library of diploid homozygous transcriptional regulator knockout (TRKO) mutants were screened to identify …

The Essential Nutrients For Methanococcus Maripaludis: Growth On Montmorillonite, Hunter William Waddell

Health, Human Performance and Recreation Undergraduate Honors Theses

When the topic of life on Mars gets brought up, our minds automatically jump to thinking of the definition of life as any advanced creature. But I am looking at life on a much smaller scale. A group of Archaea called methanogens live on Earth in some very normal as well as extreme conditions, and in the last few decades scientists have been questioning if they could even be found on the planet Mars. These microbes use hydrogen gas as their energy source and produce methane as a byproduct, which has been found in relatively significant amounts on Mars. It …

The Effects Of Electrostatic Spraying With Organic Acids In The Disintegration Of Biofilms Formed By E.Coli O157:H7 And Salmonella Typhimurium On Spinach And Cantaloupe, Ahmad Almasoud

Graduate Theses and Dissertations

Outbreaks from the consumption of fresh produce are a concern in the United States. The consumptions of fresh produce have increased recently which expose a large segment of society to such outbreaks. Spinach and cantaloupe are minimally heated or processed before consumption which makes them a possible source of foodborne illness. The objective of this research was to investigate the effect of organic acids alone and in combination to reduce attached Salmonella Typhimurium (S.T) and Escherichia coli O157:H7 (E.coli) on spinach and cantaloupe, and to disintegrate biofilm formed by these pathogens by electrostatically spraying with two organic acids. To quantify …

Impacts Of The Deepwater Horizon Oil Spill On Microbial-Mediated Cellulose Decomposition In Mississippi Gulf Coast Salt Marshes, Jerrid Shawn Boyette

Master's Theses

Field studies were conducted to examine the effects of the Deepwater Horizon oil spill on rates of marsh organic matter decomposition. Decomposition in surface and subsurface marsh sediments was assessed in stands of Spartina alterniflora and Juncus roemerianus in 9 Mississippi Gulf Coast marshes exposed to differing oiling intensities. The cotton strip bioassay technique was used as a proxy for cellulose decomposition. In addition, rates of microbial respiration, fungal biomass (ergosterol) and nutrients (C:N, C:P) of surface sediment cotton strips were also quantified. Subsurface cotton strip decay, as determined by losses in tensile strength, were significantly different among marsh …

The Hippo Pathway Effector Yki Downregulates Wg Signaling To Promote Retinal Differentiation In The Drosophila Eye, Erika Lynn Wittkorn, Ankita Sarkar, Kristine Garcia, Madhuri Kango-Singh, Amit Singh

Biology Faculty Publications

The evolutionarily conserved Hippo signaling pathway is known to regulate cell proliferation and maintain tissue homeostasis during development. We found that activation of Yorkie (Yki), the effector of the Hippo signaling pathway, causes separable effects on growth and differentiation of theDrosophila eye. We present evidence supporting a role for Yki in suppressing eye fate by downregulation of the core retinal determination genes. Other upstream regulators of the Hippo pathway mediate this effect of Yki on retinal differentiation. Here, we show that, in the developing eye, Yki can prevent retinal differentiation by blocking morphogenetic furrow (MF) progression and R8 specification. …

The Uptake And Incorporation Of Exogenous Fatty Acids Confer Phenotypic Advantages To Acinetobacter Baumannii, Saba A. Munir

Honors Theses

AIM: Acinetobacter baumannii is a ubiquitous gram-negative bacterium found on a variety of surfaces that include skin, hair, and soil. Some gram-negative bacteria like A. baumannii have the ability to acquire and incorporate fatty acids into their phospholipid membranes. Known as ‘Iraqibacter,’ A. baumannii has emerged as a significant cause of nosocomial infections in the United States and abroad. This study was designed to determine whether structural alterations occur in A. baumannii upon exposure to a wide range of polyunsaturated fatty acids (PUFAs) as well as the significance of this phenomenon in terms of survival and resistance to stress. Thin …

Understanding The Evolution Of Aggregative Multicellularity: A Molecular Phylogenetic Study Of The Cellular Slime Mold Genera Sorodiplophrys And Pocheina, Alexander Tice

Graduate Theses and Dissertations

Cellular slime molds are amoeboid protists that have a unicellular trophic phase and multicellular dispersal stage formed through the aggregation of individuals in their life cycles. These organisms were once thought to form a monophyletic group in the Mycetozoa. After careful morphological, ultrastructural, and molecular studies, cellular slime molds are now thought to be distantly related organisms that have all converged on the cellular slime mold habit. The following thesis consists of two molecular phylogenetic studies on two named genera of cellular slime mold for which little or no molecular data were publically available. In the first study, gene sequence …

Characterization And Investigation Of Fungi Inhabiting The Gastrointestinal Tract Of Healthy And Diseased Humans, Mallory J. Suhr

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Gastrointestinal microbiome studies have failed to include fungi in total community analyses. As a result, their diversity and function in the gut is poorly understood. Recent work has begun to uncover the role intestinal fungi play in diet, immune system development, interactions with other microorganisms in the gut, and pathogenesis of diseases. Advances in sequencing technologies allow for the ability to profile the fungal gut microbiome (“mycobiome”) in healthy and diseased states. This thesis explores the mycobiome in 1) healthy humans with a vegetarian diet and 2) pediatric small bowel transplant recipients that develop fungal bloodstream infections.

The gut mycobiome …

The Effect Of Activation Induced Cytidine Deaminase Phosphorylation And Herpes Virus Uracil Dna Glycosylase On Antibody Diversification, Marc Macaluso

Dissertations and Theses (Open Access)

Activation-induced cytidine deaminase (AID) is a mutagenic enzyme that is expressed in mammalian B-cells and initiates the antibody diversification processes of somatic hypermuntation (SHM) and isotype class switch recombination (CSR). AID is targeted to the immunoglobulin gene locus where it deaminates cytosines to generate uracil residues in DNA. This generates guanine-uracil (U:G) mismatch lesion which are recognized by uracil DNA glycosylase (UNG), a DNA repair enzyme that removes uracil from DNA and triggers downstream repair of the lesion. While UNG is a ubiquitously expressed DNA repair enzyme, its recognition and removal of AID introduced uracils is essential in both SHM …

Characterization Of The Innate Response To The Ragb Protein Of Porphyromonas Gingivalis., Justin Hutcherson

Electronic Theses and Dissertations

More than 64 million people in the US suffer from some form of periodontal disease. Periodontal diseases are bacterial infections of the hard and soft tissues surrounding the teeth which can lead to tooth loss. Periodontal tissue destruction is caused by inflammatory host-pathogen interactions. Porphyromonas gingivalis is a major causative agent of periodontal diseases and is a keystone periodontal pathogen. The 55kDa immunodominant RagB outer membrane protein of P. gingivalis has been proposed to facilitate iron transport. However, potential interactions between RagB and the innate response have not been examined. RagB homologues in gut Bacteroidetes have been associated with inflammatory …

Critical Insights Into The Pathogenesis Of Clinical Isolates Of Pandemic Influenza A(H1n1) 2009 Virus In Mouse And Ferret Models., Jeremy V. Camp 1980-

Electronic Theses and Dissertations

Influenza A virus (IAV) is a minus-sense, segmented, single-stranded RNA virus that infects the respiratory tract of humans and can cause severe illness. Novel IAV variants perpetually emerge on every continent, and the emergence of variants with increased transmissibility and/or pathogenesis in the human population is a serious concern for global public health. Infection with IAV typically causes an acute, self-limiting upper respiratory tract disease. However, severe IAV disease is characterized by infection of the lower respiratory tract which can lead to pneumonia and may result in the development of acute respiratory distress syndrome (ARDS). Viral and host contributions to …

Early Host Response And Immune Signaling To 2009 Pandemic Influenza A (H1n1) Viruses In Primary Cell Culture Models., Rachael Lask Gerlach

Electronic Theses and Dissertations

Influenza A virus (IAV) subtypes and even genotypes within subtypes can show differences in tropism (host, cell type), magnitude of infection, immune response and progression of illness. My dissertation focused on the development and use of two in vitro physiologically-relevant human cell culture models, well-differentiated normal human bronchial epithelial (wdNHBE) cells and human monocyte-derived macrophages (MDM) for the study of early IAV-host interactions. These models have given new insight into early host responses to seasonal H1N1 (BN59) and two pandemic A(H1N1)2009 viruses or H1N1pdm herein. The H1N1pdm are clinical isolates from a fatal (A/KY/180/10) and nonfatal (A/KY/136/09) case. In the …

Phosphotransacetylase And Xylulose 5-Phosphate/Fructose 6-Phosphate Phosphoketolase: Two Eukaryotic Partners Of Acetate Kinase, Tonya Taylor

All Dissertations

Although acetate is a predominant metabolite produced by many eukaryotic microbes, far less attention has been given to acetate metabolism in eukaryotes than in bacteria and archaea. Acetate kinase (Ack), which catalyzes the reversible phosphorylation of acetate from ATP, is a key enzyme in bacterial acetate metabolism. Ack primarily partners with phosphotransacetylase (Pta), which catalyzes the generation of acetyl phosphate from acetyl-CoA, but can also partner with xylulose 5-phosphate/fructose 6-phosphate phosphoketolase (Xfp), which produces acetyl phosphate from either xylulose 5-phosphate or fructose 6-phosphate. The Ack-Pta pathway, found primarily in bacteria, is also present in lower eukaryotes such as the green …

Characterization Of Putative Exbb And Exbd Leads To The Identification Of A Potential Tol-Pal System In Rhizobium Leguminosarum Atcc 14479, Valeria Barisic

Electronic Theses and Dissertations

Rhizobium leguminosarum is a Gram negative nitrogen-fixing soil bacterium. Due to the limited bioavailability of iron, bacteria utilize siderophores that scavenge and bind available iron. The transport of iron-siderophore complexes is achieved by the TonB-ExbB-ExbD complex. We have previously shown that a functional TonB protein is necessary for iron transport by creating ΔtonB mutants and assessing their growth and 55Fe-siderophore transport ability. We attempted to identify and characterize the roles of putative exbB and exbD genes using a similar approach. Growth curves and sequence analyses suggest putative exbB and exbD may be the tolpal-associated genes tolQ and tolR. Phenotypic and …

Evaluation Of Tulane Virus As A Surrogate For The Study Of Human Norovirus, Sabastine Eugene Arthur

Graduate Theses and Dissertations

Among all known causes of acute gastroenteritis, human noroviruses (HuNoV) are the primary cause (68%) of outbreaks and are associated with 78% of illnesses, 46% of hospitalizations, and 86% of deaths. The main obstacle to studying the pathogenesis of HuNoV is the lack of cell culture system and small animal model. Murine norovirus (MNV) and feline calicivirus (FCV) have been utilized as model surrogate viruses to study HuNoV. In this research, a more recent surrogate virus, Tulane virus (TV), was evaluated for physicochemical stability and environmental persistence. The primary goal was to determine the suitability of TV as a surrogate …

Management Of A Primordial Problem: Redox-Sensitive Transcriptional Regulation In Methanosarcina Acetivorans, Ryan Christopher Sheehan

Graduate Theses and Dissertations

The primordial Earth which hosted the first forms of life was an environment free of oxygen. Early organisms utilized metabolisms dependent upon anaerobic conditions and incorporated systems to which oxygen is deleterious. As the content of oxygen in Earth's atmosphere increased, anaerobic organisms had to acquire methods to sense and combat oxygen and reactive oxygen species. Several mechanisms were advantageous to such anaerobic organisms which correlated transcriptional processes with the redox state of the cell so that energy may be conserved and oxygen stress recovery genes activated during periods of oxidative stress. Iron sulfur (Fe-S) cluster cofactors incorporated within RNA …

A Phylogenetic Analysis Of Dictyostelium Purpureum Based On Nuclear Rdna Sequences, Mahmoud Suliman

Graduate Theses and Dissertations

Dictyostelids (cellular slime molds) are eukaryotic microorganisms that have both unicellular and multicellular stages during their life cycle. In this study, a molecular phylogenetic analysis was conducted for isolates of one species (Dictyostelium purpureum) based DNA sequences of the ITS, 5.8S and SSU regions of nuclear rDNA. Moreover, a detailed morphological study was carried out using images obtained with both dissecting and compound microscopes. Mating experiments were carried out to assess macrocysts formation between each pair of isolates. The constructed molecular phylogenetic trees indicate that (1) D. purpureum isolates are more closely related to each other than to other species …