Organisms Commons^™

Alzheimer’S Disease Genetics And Short-Chain Fatty Acid Treatment In Studies Of The Murine Gut Microbiome, Diana Zajac

Theses and Dissertations--Physiology

Elucidating the relationship of the gut microbiome in Alzheimer's Disease (AD) risk and pathogenesis is an area of intense interest. Since 60 to 80% of AD risk is related to genetics and APOE alleles represent the most impactful genetic risk factors for AD, their mechanism(s) of action are under intense scrutiny.

First, I conducted a study on APOE targeted replacement mice to investigate the impact of APOE alleles on the murine gut microbiome. The relative abundance of bacteria from the family Ruminococacceae and related genera increased with APOE2 status. The relative abundance of the class Erysipelotrichia increased with APOE4 status, …

Knockout Of Endospanin 1 Via Crispr In Zebrafish, Danio Rerio, Jared Kittinger

Williams Honors College, Honors Research Projects

I made endospanin 1 knockout (KO) zebrafish to examine its effects on lipid and bone metabolism. Endospanin 1, or leptin receptor overlapping transcript (leprot), is a cytosolic protein linked to the protein hormone leptin that influences the trafficking of leptin receptors to the plasma membrane of cells. Genes for endospanin and tyrosinase (a pigmentation enzyme) were targeted via a microinjection of guide RNAs and CRISPR Cas9 into zebrafish embryos at 2-4 cell stages. I was able to disrupt the endospanin 1 gene (based upon the disruption of tyrosinase), but very few mutant zebrafish fully developed into adults. Only low KO …

Assesment Of Antibiotic Resistant Gene Expression In Clinical Isolates Of Pseudomonas Aeruginosa, Dustin Esmond

Biology Theses

Increasing prevalence of nosocomial infections by antimicrobial resistant pathogens resulting in higher mortality rates and financial burden is of great concern. Pseudomonas aeruginosa represents one of six highly virulent “ESKAPE” pathogens that exhibit considerable intrinsic drug resistance as well as mechanisms for acquiring further resistance. As many of these mechanisms are regulated through gene expression, we sought to identify regulatory strategies and patterns at play in 23 clinical isolates collected from Baku, Azerbaijan and Tyler, Texas, USA. Real-time quantitative polymerase chain reaction was performed on six gene targets implicated in resistance and contrasted with antibiotic phenotypes. We found AmpC cephalosporinase …

The Role Of Manganese In Streptococcus Sanguinis, Tanya M. Puccio

Theses and Dissertations

Streptococcus sanguinis is primarily associated with oral health as a commensal bacterium. As an opportunistic pathogen, S. sanguinis is capable of colonizing heart valve vegetations, leading to the disease infective endocarditis. Previous studies from our lab have identified the high-affinity manganese transporter SsaACB as important for endocarditis virulence. The impact that manganese depletion has on S. sanguinis had never been evaluated and a secondary manganese transporter has not been identified. Thus, we employed the use of a fermentor to control large-scale growth over time and depleted manganese in an ΔssaACB mutant using a metal chelator, EDTA. The changes in …

Clpxp-Regulated Proteins Suppress Requirement For Reca In Dam Mutants Of Escherichia Coli K-12, Amie Savakis

Masters Theses

Double strand breaks (DSB) are a common source of DNA damage in both prokaryotes and eukaryotes. If they are not repaired or are repaired incorrectly, they can lead to cell death (bacteria) or cancer (humans). In Escherichia coli, repair of DSB are typically accomplished via homologous recombination and mediated by RecA. This repair pathway, among others, is associated with activation of the SOS response. DNA adenine methyltransferase (dam) mutants have an increased number of DSB and, therefore, are notorious for being RecA-dependent for viability. Here, we show that the synthetic lethality of Δdam/ΔrecA is suppressed when clpP is removed, suggesting …

Studies Of Norspermidine Uptake In Drosophila Suggest The Existence Of Multiple Polyamine Transport Pathways, Michael Dieffenbach

Honors Undergraduate Theses

Polyamines are a class of essential nutrients involved in many basic cellular processes such as gene expression, cell proliferation, and apoptosis. Without polyamines, cell growth is delayed or halted. Cancerous cells require an abundance of polyamines through a combination of synthesis and transport from the extracellular environment. An FDA-approved drug, D,L-α-difluoromethylornithine (DFMO), blocks polyamine synthesis but is ineffective at inhibiting cell growth due to polyamine transport. Thus, there is a need to develop drugs that inhibit polyamine transport to use in combination with DFMO. Surprisingly, little is known about the polyamine transport system in humans and other eukaryotes. Understanding the …

Mechanisms Of Adaptation In The Newly Invasive Species Brachypodium Sylvaticum (Hudson) Beauv., Gina Lola Marchini

Dissertations and Theses

It is common knowledge that invasive species cause worldwide ecological and economic damage, and are nearly impossible to eradicate. However, upon introduction to a novel environment, alien species should be the underdogs: They are present in small numbers, possess low genetic diversity, and have not adapted to the climate and competitors present in the new habitat. So, how are alien species able to invade an environment occupied by native species that have already adapted to the local environment? To discover some answers to this apparent paradox I conducted four ecological genetic studies that utilized the invasive species Brachypodium sylvaticum (Hudson) …

Proof-Of-Concept Of Environmental Dna Tools For Atlantic Sturgeon Management, Jameson Hinkle

Theses and Dissertations

Abstract

The Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus, Mitchell) is an anadromous species that spawns in tidal freshwater rivers from Canada to Florida. Overfishing, river sedimentation and alteration of the river bottom have decreased Atlantic Sturgeon populations, and NOAA lists the species as endangered. Ecologists sometimes find it difficult to locate individuals of a species that is rare, endangered or invasive. The need for methods less invasive that can create more resolution of cryptic species presence is necessary. Environmental DNA (eDNA) is a non-invasive means of detecting rare, endangered, or invasive species by isolating nuclear or mitochondrial DNA (mtDNA) from the …

Characterization Of Staphylococcus Aureus Lipase, Vithooshan Vijayakumaran

Electronic Thesis and Dissertation Repository

USA300, a strain of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA), has become prevalent in the community. Colonization of human skin requires mechanisms that allow this bacterium to overcome the innate immune defenses on the skin, including secretion of antimicrobial lipids. Antimicrobial lipids inhibit S. aureus growth and induce the staphylococcal proteolytic cascade, producing aureolysin (Aur) which processes the lipase glycerol ester hydrolase (Geh). Nearly all S. aureus strains secrete Geh, yet little information exists concerning its function. Using purified Aur and Geh we confirm that aureolysin processes proGeh to Geh. We then confirmed that geh was required for lipase activity …

Whole Genome Sequencing Of L.Monocytogenes And L.Innocua : A Basis For Comparative Genomics Of The Genus Listeria, Rachel Purcell

Theses

Listeria monocytogenes is a gram-positive, food-borne human and animal pathogen. L.innocua is a non-pathogenic species the most closely related to L. monocytogenes. Comparative genomics between a pathogenic and a closely related non-pathogenic species is a powerful approach for identifying genes or regions on the chromosome, which might be involved in virulence. Therefore whole genome sequencing of these two organisms was undertaken. The strategy used was based on a random approach combined with end-sequencing of a medium insert library for the finishing phase. Based on the available sequence data for these two species an in silico analysis for the presence of …

Methicillin Resistant Staphylococcus Aureus (Mrsa): Molecular Detection And Dna Fingerprinting, Leslie Cotter

Theses

Throughout the 1990s, the incidence of methicillin-resistant Staphylococcus aureus has increased in many health care areas including acute and chronic care facilities, outpatient clinics and in the community. Once introduced into a health care environment, this nosocomial pathogen can spread rapidly and as MRSA are resistant to multiple antibiotics, treatment is often difficult. Therefore effective infection control measures are required to prevent cross-infection and further spread of endemic strains.

In this study, a sensitive and specific triplex-PCR assay was designed for MRSA detection, wherein three genes, the methicillin resistance gene (mecA). femA and the extracellular thermonuclease gene (rmc) were simultaneously …

Experimentation To Develop Procedures To Be Used In The Investigation Of The Effects Of Restriction On The Unmodified Dna Of The Bacteriophage Lamda, John Haynes

Honors Theses

The results of experimentation approximately twenty years ago with variuos bacteriophages by Ralston and Krueger¹⁶, Anderson and Felix¹, Luria and Human¹², and by Bertani and Weigle² have shown that the host range of a given phage depends directly on the bacterial strain on which the phage has last propagated. This event came to be known as host-induced modification or host-controlled variation. As this phage host range is controlled by the host environment and can be altered from one generation to another it has, according to Luria, made microbiology "the last stronghold of Lamarckism" …