Microbiology Commons^™

Dissecting The Mechanism Of Action Of A Novel Antifungal Peptide, Cody Bullock

Graduate Theses and Dissertations

There is an urgent need for novel treatments for Candida infections. The utility of antimicrobial peptides for antifungal therapy has garnered interest in recent years. One promising family of peptides is the Histatins, a family of naturally-occurring peptides secreted into the oral cavity that display antimicrobial activity. Histatin 5 is a twenty-four amino acid peptide with strong antifungal activity. Studies from our laboratory have identified a small histatin-derived peptide, KM29, that yields fungicidal activity 10-fold greater than Histatin 5 against multiple Candida species. Our laboratory has focused on understanding the mechanism of action of KM29 to further develop it as …

Gut Symbiont Viability In Honey Bees Exposed To Agrochemical Stressors, Bryant Justin Gabriel

Department of Entomology: Dissertations, Theses, and Student Research

The honey bee gut microbiome is essential for protecting this pollinator against abiotic and biotic stressors, including the prevention of harmful gut parasites and pathogens. Previous studies have not only demonstrated a linkage of bee gut dysbiosis to increased immunodeficiencies and pathogen sensitivities, but also report the maladaptation of the gut microbiome in bees exposed to agricultural and apicultural chemistries. There are few techniques available that allow for a simple and reliable analysis of the relative proportions of live and dead gut microbes in bees exposed to these chemistries. Previous techniques for measuring gut symbiont dysbiosis are temporally limited by …

Effects Of Toxic Fescue Exposure On Vaginal Microbial Communities Of Crossbred Beef Cows, Abby Ratton

Animal Science Undergraduate Honors Theses

The consumption of toxic fescue by beef cattle results in several adverse physiological effects such as reduced reproductive success, severe vasoconstriction resulting in hoof sloughing, low body condition scores, hyperthermia, decreased prolactin levels, and reduced hair shedding. The purpose of this study is to characterize bacterial community of the reproductive tract as a potential predictor for toxin exposure. One-hundred fall-calving crossbred cows were allocated to graze Toxic (Toxic: n=50) or Novel (Novel: n= 50) fescue pastures for five months (March-August). Treatments were blocked by sire breed (Charolais or Hereford) and by parity (first, second, third). Animals rotated pastures biweekly and …

Low Grade Mullerian Adenosarcoma Of Pouch Of Douglas Recurring As Bilateral Ovarian High Grade Mullerian Adenosarcoma With Rhabdomyosarcomatous Overgrowth After 11 Years, Sandeep Kumar, Muhammad Raza, Muhammad Usman Tariq

Department of Pathology and Laboratory Medicine

Mullerian adenosarcoma (MA) of ovary with sarcomatous (rhabdomyoblastic) overgrowth is an extremely rare malignant type of female genital tract neoplasm. These tumours are highly aggressive and presence of heterologous elements is associated with worse prognosis. A 44 year old female presented with lower abdominal pain and distension. She had history of removal of tumour from pouch of Douglas in 2006 for which she did not receive any additional treatment nor did she keep continuous follow up. Current preoperative radiological examination revealed bilateral ovarian masses. She underwent abdominal hysterectomy with bilateral oophorectomy. Microscopic examination revealed biphasic tumours exhibiting sarcomatous overgrowth with …

Mechanism Of Incorporation And Repair Of Uracil At Highly Transcribed Genes In Saccharomyces Cerevisiae, Norah Auma Owiti

Dissertations and Theses (Open Access)

Recombination and mutagenesis are elevated by high levels of transcription. The correlation between transcription and genome instability is largely explained by the topological and structural changes in DNA and the associated physical obstacles generated by the transcription machinery. However, such explanation does not directly account for the unique types of mutations originating from the non-canonical residues such as uracil, which are also elevated at highly transcribed regions. Apurinic/Apyrimic or Abasic (AP) sites derived from uracil excision, accumulate at a higher rate in actively transcribed regions of the genome in S. cerevisiae and are primarily repaired by base excision repair (BER) …

Evaluation Of A Human Papillomavirus Genotyping Assay For Cervical Cancer Screening In Tanzania, Kandali S. Kapie

School of Biological Sciences: Dissertations, Theses, and Student Research

Abstract: Mucosal high-risk Human papillomavirus (HR-HPV) has been identified as the primary factor in causing cervical cancer, the most common cancer in women of low and middle-income countries (LMICs). Cervical cancer screening, incorporating the HPV test shown to be more advantageous than screening by visual inspection with acetic acid (VIA) alone. However, due to resources constrain these countries could not afford the available HPV tests. We, therefore, validated a cost-effective Multiplex PCR HPV (mPCR) assay, a recently developed assay for detecting sixteen genital HPV, fourteen HR-HPV and 2 low-risk genotypes. We postulate that this HPV multiplex assay will be at …

African Trypanosomes Evade Immune Clearance By Oglycosylation Of The Vsg Surface Coat, Jason Pinger, Dragana Nešić, Liaqat Ali, Francisco Aresta-Branco, Mirjana Lilic, Shanin Chowdhury, Hee-Sook Kim, Joseph Verdi, Jayne Raper, Michael A. J. Ferguson, F. Nina Papavasiliou, C. Erec Stebbins

Publications and Research

The African trypanosome, Trypanosoma brucei spp., is a paradigm for antigenic variation, the orchestrated alteration of cell surface molecules to evade host immunity. The parasite elicits robust antibody-mediated immune responses to its Variant Surface Glycoprotein (VSG) coat, but evades immune clearance by repeatedly accessing a large genetic VSG repertoire and “switching” to antigenically distinct VSGs. This persistent immune evasion has been ascribed exclusively to amino acid variance on the VSG surface presented by a conserved underlying protein architecture. We establish here that this model does not account for the scope of VSG structural and biochemical diversity. The 1.4Å resolution crystal …

Contributions Of The Gp120 Variable Loops To Envelope Glycoprotein Trimer Stability In Primate Lentiviruses, Dane M. Bowder

School of Biological Sciences: Dissertations, Theses, and Student Research

Human Immunodeficiency Virus (HIV) is the etiological agent of AIDS and is responsible for the AIDS pandemic worldwide. According to UNAIDS, as of 2016, there were approximately 36.7 million people living with HIV globally, and 1.8 million new infections that year. While antiretroviral therapies and education continue to reduce these numbers, a preventative vaccine is still required to curb this epidemic. The envelope glycoprotein trimer of HIV, which is the sole protein on the surface of the virus and facilitates entry of the virus into host cells, is of keen interest to the HIV vaccine and drug-development field. Recently, the …

Comparative Microbial Community Dynamics In A Karst Aquifer System And Proximal Surface Stream In Northwest Arkansas, Josue Rodriguez

Graduate Theses and Dissertations

Northwest Arkansas has well-developed karst systems, with numerous sinking streams and springs. Karst conduits make it easy for contaminants to enter groundwater systems, degrading the water quality and destroying fragile karst ecosystems. With the increase of urbanization, potential threats in the form of fecal contamination may prove to be more of a problem. The purpose of this research is to compare the difference between microbial communities within two different settings, a karst aquifer and a surface stream. The microbial communities within Blowing Spring Cave and Little Sugar Creek were detected and identified in water and sediment samples. Samples were also …

Grapevine Vein Clearing Virus: Epidemiological Patterns And Construction Of A Clone, Cory Von Keith

Graduate Theses/Dissertations

Grapevine vein clearing virus (GVCV) is a recently discovered virus belonging to the Badnavirus genus. Characteristic to its name, the virus is associated with a disease where symptoms manifest as pronounced vein-clearing, resulting in severe berry deformation and vine decline in susceptible grape varieties. Sustainable production of wine is dependent on healthy plants. The associated disease is mainly found in Midwest vineyards. Attempts were made in this thesis to provide evidence of causality of the virus to the associated disease and to infer the historical path and migration pattern of GVCV. Conclusions and discussions will provide grape producers with the …

Post-Transcriptional Regulation Of Rsma In Pseudomonas Aeruginosa, Ian Miller

Electronic Theses and Dissertations

Pseudomonas aeruginosa is a Gram-negative bacillus found in numerous environments. Gene regulatory mechanisms such as; Two-Component Systems, transcriptional and post-transcriptional regulators, and small non-coding RNAs control the expression of virulence factors that allow P. aeruginosa to initiate acute infections and persist as a chronic infection. A significant post-transcriptional regulator involved in these regulatory networks is the Regulator of Secondary Metabolites (RsmA). In this study, we investigated the contribution of a putative stem-loop on expression of RsmA. We constructed rsmA leader fusions to measure translation with and without the stem-loop present. Secondly, we introduced point mutations to disrupt the formation …

Characterization Of Fgf-Mediated Sonic Hedgehog Expression During Limb Development, Billy A. Watson

Loma Linda University Electronic Theses, Dissertations & Projects

Crosstalk between Fibroblast Growth Factors (FGFs) and Sonic hedgehog (SHH) is essential for proper limb development; however, the molecular mechanisms involved in this process remain unclear. Via comparative transcriptome analysis and gene knockdown and overexpression studies, we identified the transcription factor Lim homeobox 2 (LHX2) as an intermediate in FGF-directed SHH expression. We determined that FGF signaling was necessary for LHX2 expression and demonstrated that LHX2 is a primary transcription target of FGF signaling through the RAS and AKT pathways. Additionally, loss of LHX2 in the distal limb results in decreased SHH expression and a truncated limb within 24 hours …

Dietary Inclusion Of Enriched Chicken Bone Broth Prevents Trigeminal Sensitization Meditated By Early Life Stress, Orion Peterson

Graduate Theses/Dissertations

Early life stress is considered a risk factor for development of migraine, which is a prevalent painful neurological disorder involving sensitization and activation of trigeminal neurons, and irritable bowel syndrome, a condition often comorbid with chronic migraine. The focus of my study was to determine the effects of early life stress and dietary inclusion of enriched chicken bone broth on trigeminal nociceptor sensitization and the gut microbiota. Adult Sprague-Dawley male “sender” rats subjected to primary traumatic stress were placed next to breeding or pregnant female rats that served as “receiver” rats (secondary traumatic stress) and in proximity to the offspring …

Sodium Pyruvate Alters The Immune Response To Influenza A Virus Infection In Macrophages, Hazzar Abysalamah

Graduate Theses/Dissertations

ABSTRACT

Pyruvate is the end product of glycolysis. It can either be transported into the mitochondria for use in the TCA cycle or be used to regenerate NAD⁺ during fermentation or aerobic glycolysis (also called the Warburg Effect). I recently discovered that addition of sodium pyruvate to the culture medium during infection of macrophages with influenza A virus affects the production of cytokines involved in immune signaling. While infection of macrophages with influenza A virus resulted in high levels of cytokines (IL-6, IL-1β, and TNF-α) in the absence of sodium pyruvate, the addition of sodium pyruvate significantly impaired cytokine …

Plant And Microbial Responses To Repeated Cu(Oh)2 Nanopesticide Exposures Under Different Fertilization Levels In An Agro-Ecosystem, Marie Simonin, Benjamin P. Colman, Weiyi Tang, Jonathan D. Judy, Steven M. Anderson, Christina M. Bergemann, Jennifer D. Rocca, Jason M. Unrine, Nicolas Cassar, Emily S. Bernhardt

Plant and Soil Sciences Faculty Publications

The environmental fate and potential impacts of nanopesticides on agroecosystems under realistic agricultural conditions are poorly understood. As a result, the benefits and risks of these novel formulations compared to the conventional products are currently unclear. Here, we examined the effects of repeated realistic exposures of the Cu(OH)₂ nanopesticide, Kocide 3000, on simulated agricultural pastureland in an outdoor mesocosm experiment over 1 year. The Kocide applications were performed alongside three different mineral fertilization levels (Ambient, Low, and High) to assess the environmental impacts of this nanopesticide under low-input or conventional farming scenarios. The effects of Kocide over time were …

In Vivo Antimycobacterial Studies Of Toussaintine A-Chitosan Nanocomposites, Edward Rwegasila, Joan J.E. Munissi, Egid B. Mubofu, Stephen S. Nyandoro, Paul Erasto

Tanzania Journal of Science

Chitosan (CS, molecular weight (MW) 20.2 kDA, stability of 210 °C and degree of deacetylation (DD) 73.31%) was obtained by deacetylation of chitin extracted from shrimp (Litopenaeus vannamei) shell wastes. The encapsulation of the studied bioactive natural product, toussaintine A (TA) isolated from the leaves of Toussaintia orientalis, on a chitosan-tripolyphosphate (CS/TPP) nanoformulation was attained through ionotropic gelation. Characterization of pure CS, CS/TPP and TA-CS/TPP nanocomposites was carried out by FTIR and SEM. The encapsulation efficiency and loading capacity of the TA were 69.33 and 0.46%, respectively. The in vitro release kinetics established an initial release of 27% of TA …

In Vivo Antimycobacterial Studies Of Toussaintine A-Chitosan Nanocomposites, Edward Rwegasila, Joan J.E. Munissi, Egid B. Mubofu, Stephen S. Nyandoro, Paul Erasto

Tanzania Journal of Science

Chitosan (CS, molecular weight (MW) 20.2 kDA, stability of 210 °C and degree of deacetylation (DD) 73.31%) was obtained by deacetylation of chitin extracted from shrimp (Litopenaeus vannamei) shell wastes. The encapsulation of the studied bioactive natural product, toussaintine A (TA) isolated from the leaves of Toussaintia orientalis, on a chitosan-tripolyphosphate (CS/TPP) nanoformulation was attained through ionotropic gelation. Characterization of pure CS, CS/TPP and TA-CS/TPP nanocomposites was carried out by FTIR and SEM. The encapsulation efficiency and loading capacity of the TA were 69.33 and 0.46%, respectively. The in vitro release kinetics established an initial release of 27% of TA …

Honey Bee And Bumble Bee Antiviral Defense, Alexander J. Mcmenamin, Daughenbaugh F. Katie, Fenali Parek, Marie C. Pizzorno, Michelle L. Flenniken

Faculty Journal Articles

Bees are important plant pollinators in both natural and agricultural ecosystems. Managed and wild bees have experienced high average annual colony losses, population declines, and local extinctions in many geographic regions. Multiple factors, including virus infections, impact bee health and longevity. The majority of bee-infecting viruses are positive-sense single-stranded RNA viruses. Bee-infecting viruses often cause asymptomatic infections but may also cause paralysis, deformity or death. The severity of infection is governed by bee host immune responses and influenced by additional biotic and abiotic factors. Herein, we highlight studies that have contributed to the current understanding of antiviral defense in bees, …

Her2 Basolateral Versus Circumferential Ihc Expression Is Dependent On Polarity And Differentiation Of Epithelial Cells In Gastric/Ge Adenocarcinoma, Shahid Pervez, Sidra Arshad, Brooj Abro

Department of Pathology and Laboratory Medicine

Aim: Antigenic expression in epithelial cells can be heterogeneous which may pose a problem in immunohistochemical (IHC) analysis of tumor markers, in particular, predictive markers like HER2. Studies have shown that epithelial cells have distinct apical and basolateral domains which are separated by tight junctions. The cell membrane in these two domains has a different composition of macromolecules and hence can have variable antigen expression on immunohistochemistry. In our study, we aimed to investigate this phenomenon of basolateral versus circumferential IHC staining of HER2 in gastric/GE adenocarcinoma.
Methods: We selected 45 cases of gastric/GE adenocarcinoma and evaluated equal number of …

Genomic Analysis Of 48 Paenibacillus Larvae Bacteriophages, Casey Stamereilers, Christopher P. Fajardo, Jamison K. Walker, Katterinne N. Mendez, Eduardo Castro-Nallar, Julianne H. Grose, Sandra Hope, Philippos K. Tsourkas

Life Sciences Faculty Research

The antibiotic-resistant bacterium Paenibacillus larvae is the causative agent of American foulbrood (AFB), currently the most destructive bacterial disease in honeybees. Phages that infect P. larvae were isolated as early as the 1950s, but it is only in recent years that P. larvae phage genomes have been sequenced and annotated. In this study we analyze the genomes of all 48 currently sequenced P. larvae phage genomes and classify them into four clusters and a singleton. The majority of P. larvaephage genomes are in the 38–45 kbp range and use the cohesive ends (cos) DNA-packaging strategy, while a minority have genomes …