Microbiology Commons^™

Phenotypic And Transcriptomic Characterization Of Colonial Phase Variation In The Cholera Pathogen Reveals A Novel Smooth Biofilm-Defective Form, Bliss Nicole Lambert

LSU Doctoral Dissertations

Biofilm formation, through the production of Vibrio polysaccharide (VPS), greatly enhances the environmental fitness and pathogenic success of Vibrio cholerae. As a result of phase variation, V. cholerae can switch from a smooth form to rugose, whose cells produce excess VPS, resulting in highly structured biofilms and greater resistance to stress. To further characterize the reversible process of phase variation, we isolated three colonial lineages. Each lineage began with a smooth parent, N16961, and contained a rugose variant derived from the parent, N16961R, as well as a smooth revertant of the rugose, N16961SD. We found clear phenotypic and transcriptomic …

Harnessing The Anopheles Microbiome To Conditionally Express Anti-Plasmodial Effectors During The Blood Meal, Jackie Shane

Electronic Theses and Dissertations

The control of vector-borne diseases such as malaria has been an extremely important research subject for hundreds of years. Because of the complex lifecycles of the pathogens that cause these diseases, finding a comprehensive treatment or preventative strategy has proven extremely difficult. Malaria alone is responsible for almost half a million deaths annually, most of them children under 5 years old. This disease is caused by parasitic protists in the genus Plasmodium that are transmitted to humans from Anopheles sp. mosquitoes. Most preventative strategies that are in use today revolve around controlling the vectors, including bed nets, insecticides, and larval …

Efficacy Of A T Cell-Biased Adenovirus Vector As A Zika Virus Vaccine, Brianna L. Bullard, Brigette N. Corder, Matthew J. Gorman, Michael S. Diamond, Eric A. Weaver

Nebraska Center for Virology: Faculty Publications

Zika virus (ZIKV) is a major public health concern due to the risk of congenital Zika syndrome in developing fetuses and Guillain-Barre syndrome in adults. Currently, there are no approved vaccines available to protect against infection. Adenoviruses are safe and highly immunogenic vaccine vectors capable of inducing lasting humoral and cellular immune responses. Here, we developed two Adenovirus (Ad) vectored Zika virus vaccines by inserting a ZIKV prM-E gene expression cassette into human Ad types 4 (Ad4-prM-E) and 5 (Ad5-prM-E). Immune correlates indicate that Ad5-prM-E vaccination induces both an anti-ZIKV antibody and T-cell responses whereas Ad4-prM-E vaccination only induces a …

Effects Of Urbanization On The Foraging Ecology And Microbiota Of The Generalist Seabird Larus Argentatus, Matthew Fuirst, Richard R. Veit, Megan Hahn, Nolwenn Dheilly, Lesley H. Thorne

Publications and Research

Larus gull species have proven adaptable to urbanization and due to their generalist feeding behaviors, they provide useful opportunities to study how urban environments impact foraging behavior and host-associated microbiota. We evaluated how urbanization influenced the foraging behavior and microbiome characteristics of breeding herring gulls (Larus argentatus) at three different colonies on the east coast of the United States. Study colonies represented high, medium and low degrees of urbanization, respectively. At all colonies, gulls frequently foraged at landfills and in other urban environments, but both the use of urban environments and gull foraging metrics differed with the degree of urbanization. …

Prokaryotic Diversity And Aqueous Geochemistry Of Subsurface Environments Of The Death Valley Regional Flow System, Joshua David Sackett

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation summarizes over four years of effort towards the completion of a Ph.D. in Biological Sciences. The work presented in this document covers a broad range of topics, but a central unifying theme is prokaryotic life in the continental subsurface. The work presented in each chapter relied heavily on cultivation-independent methods for assessing prokaryotic communities, including prokaryotic community structure reconstruction from high-throughput sequencing of 16S rRNA gene libraries and single-cell genome analysis of novel uncultivated bacteria.

Chapter 2 examines the aqueous geochemistry and prokaryotic diversity of Devils Hole, a cavernous limnocrene and sole natural habitat for the critically endangered …

Pengaruh Pupuk Hayati Majemuk Dan Pupuk Fosfor Terhadap Pertumbuhan Dan Hasil Kedelai Di Inceptisol Jatinangor, Aep Wawan Irwan, Tati Nurmala

Jurnal Kultivasi

Kedelai merupakan salah satu tanaman yang membutuhkan fosfor dalam jumlah besar. Ketersediaan P merupakan faktor pembatas utama pada pertumbuhan dan produksinya. Fosfor tidak banyak tersedia untuk tanaman, sehingga dibutuhkan pupuk hayati yang mengandung mikroorganisme untuk dapat melarutkan fosfor. Penelitian ini bertujuan untuk memperoleh dosis pupuk hayati majemuk dan pupuk P yang efektif dan dapat memberikan pengaruh terbaik terhadap pertumbuhan, komponen hasil, dan hasil tanaman kedelai kultivar Anjasmoro. Penelitian dilakukan pada bulan Maret sampai Juni 2017 di Kebun Percobaan Ciparanje, Fakultas Pertanian Universitas Padjadjaran, dengan ketinggian tempat yaitu ± 780 mdpl. Percobaan dilakukan dengan menggunakan Rancangan Acak Kelompok terdiri dari 9 …

Adaptation Mechanism And Tolerance Of Rhodopseudomonas Palustris Psb-S Under Pyrazosulfuron-Ethyl Stress, Xiang-Wen Luo, De-Yang Zhang, Teng-Hui Zhu, Xuguo Zhou, Jing Peng, Song-Bai Zhang, Yong Liu

Entomology Faculty Publications

Background: Pyrazosulfuron-ethyl is a long lasting herbicide in the agro-ecosystem and its residue is toxic to crops and other non-target organisms. A better understanding of molecular basis in pyrazosulfuron-ethyl tolerant organisms will shed light on the adaptive mechanisms to this herbicide.

Results: Pyrazosulfuron-ethyl inhibited biomass production in Rhodopseudomonas palustris PSB-S, altered cell morphology, suppressed flagella formation, and reduced pigment biosynthesis through significant suppression of carotenoids biosynthesis. A total of 1127 protein spots were detected in the two-dimensional gel electrophoresis. Among them, 72 spots representing 56 different proteins were found to be differently expressed using MALDI-TOF/TOF-MS, including 26 up- and 30 …

Investigating The Impact Of Oxidative Stress On Tetrahymena Thermophila Sirtuin,Thd 18, Emmanuel Dubuisson

Publications and Research

Sirtuins are a family of enzymes that fulfill various important biological functions. Investigators have looked for the implication of Sirtuin genes in cell signaling mechanisms, in the formation and silencing of heterochromatin, in the regulation of ion channels, and in the modulation of the cellular redox reactions[2]. Different model organisms have been previously used to conduct these studies; among them, there are yeasts, nematodes, and fruit flies. Each one has made some valuable contribution into the vast body of knowledge related to this field.

However, gaps in the understanding of Sirtuins functions still remain to be filled. In this optic, …

Sensitivity Of Salmonella Serovars And Natural Microflora To High-Pressure Pasteurization: Open Access Data For Risk Assessment And Practitioners, Abimbola Allison, Aliyar Fouladkhah

Agricultural and Environmental Sciences Faculty Research

Industrial adoption of high-pressure processing is gaining importance and momentum as an alternative method to traditional utilization of antimicrobials and heat-based pasteurization. This indicates the need for extensive validation studies and available data for feasible and efficacious adoption of the technology by practitioners and the private industry. Current dataset is obtained utilizing elevated hydrostatic pressure of 35 to 380 MPa for time intervals of 0 (untreated controls) to 10 min, for decontamination of mesophilic background microflora and inoculated Salmonella in orange juice [1]. This open accessed data could be incorporated as part of risk assessment analyses for mitigating the risk …

Stress Response Mechanisms Of Listeria Monocytogenes, Oindrila Paul

Dissertations

Listeria monocytogenes is a Gram-positive, facultative intracellular food-borne pathogen that causes the disease listeriosis. In order to establish an infection, L. monocytogenes must survive multiple stressors encountered within the gastrointestinal tract, including alterations in pH, bile, salt, and oxygen availability. This dissertation focused on understanding the stress response of L. monocytogenes to bile. Bile acts as a bactericidal agent by disrupting the membrane integrity and causing instability to macromolecules like DNA. Thus, a bacterium must be able to maintain its membrane architecture, composition and integrity.

Often times, bacteria will modulate their fatty acid composition in the membrane to cope with …

Distribution Of Dengue And Zika Virus Igg Immunoglobulin, Madison Smith, Awadalkareem Adam, Anuja Mathew

Senior Honors Projects

Introduction. Dengue Virus (DENV) and Zika Virus (ZIKV) are viruses that belong to the Flavivirus family. They are transmitted by the Aedes aegypti species of mosquitoes. Infection with DENV can result in no symptoms, mild symptoms which include fever, rash, and headache (dengue fever) or more severe symptoms which include hemorrhage, dengue hemorrhagic fever (DHF) and shock, dengue shock syndrome (DSS). ZIKV, until recently caused mild disease but an outbreak in Brazil was associated with fetal complications such as microcephaly or Guillain-Barré syndrome in adults. Due to the similarity between ZIKV and DENV, antibodies (Abs) generated in humans to these …

Methanogens, Plausible Extraterrestrial Life Forms On Mars, And Their Tolerance To Increasing Concentrations Of Illite Clay, Chandler Kern

Biological Sciences Undergraduate Honors Theses

Methanogens, some of Earth’s most primitive prokaryotic organisms, are candidates for possible life forms capable of inhabiting Mars. Specifically, four different species (Methanobacterium formicicum, Methanococcus maripaludis, Methanosarcina barkeri, Methanothermobacter wolfeii) were analyzed for their tolerance to the presence of illite clay. Illite is a crystalline mineral that has been identified from regions of Mars’s surface. Results indicated that all four species grew with some success in the illite at different concentrations. This experimentation with methanogens’ abilities to survive and reproduce in the presence of illite allows for a more accurate understanding of the potential capability of microbial …

Virulence Regulation In Pseudomonas Aeruginosa Via The Alginate Regulators, Algu And Algr, The Posttranscriptional Regulator, Rsma, And The Two-Component System, Algz/R, Sean Stacey

Electronic Theses and Dissertations

Pseudomonas aeruginosa is a Gram-negative bacillus able to colonize a wide variety of environments. In the human host, P. aeruginosa can establish an acute infection or persist and create a chronic infection. P. aeruginosa is able to establish a niche and persist in human hosts by using a wide array of virulence factors used for: movement, killing host cells, and evading immune cells and antibiotics. Understanding virulence factors and their regulation has proved to be an important means of combating the morbidity and mortality of P. aeruginosa as well as the ever-increasing threat of drug resistance. By targeting virulence factors …

Engineering Yeast To Evaluate Human Proteins Involved In Selective Rna Packaging During Hiv Particle Production, Ryan M. Bitter

Master's Theses

Despite recent advances in antiretroviral therapy, nearly 37 million people continue to live with human immunodeficiency virus (HIV). Basic and applied research on the assembly of HIV could be enhanced by using a genetically tractable organism, such as yeast, rather than mammalian cells. While previous studies showed that expression of the HIV Gag polyprotein in Saccharomyces cerevisiae spheroplasts resulted in the production of virus-like particles (VLPs), many questions regarding the utility of yeast in HIV assembly remain uninvestigated. Here, we report use of S. cerevisiae for both the production of VLPs with selectively packaged RNA and to evaluate the human …

Dna Methylation By Restriction Modification Systems Affects The Global Transcriptome Profile In Borrelia Burgdorferi, Timothey Casselli, Yvonne Tourand, Adam Scheidegger, William K. Arnold, Anna Proulx, Brian Stevenson, Catherine A. Brissette

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Prokaryote restriction modification (RM) systems serve to protect bacteria from potentially detrimental foreign DNA. Recent evidence suggests that DNA methylation by the methyltransferase (MTase) components of RM systems can also have effects on transcriptome profiles. The type strain of the causative agent of Lyme disease, Borrelia burgdorferi B31, possesses two RM systems with N6-methyladenosine (m6A) MTase activity, which are encoded by the bbe02 gene located on linear plasmid lp25 and bbq67 on lp56. The specific recognition and/or methylation sequences had not been identified for either of these B. burgdorferi MTases, and it was not previously known whether these RM …

Assessment Of Salmonella Enterica Biofilms And Expression Differences Among Serovars, Zhaohao Shi

Graduate Theses and Dissertations

Biofilms are communities of microorganisms associated by a matrix of extracellular polymers. In this state, microorganisms occupy an ecological niche distinct from their free-floating, planktonic counterparts. Also, biofilm bacteria become biologically unique as they form communities and lose motility. The acquisition of these physiological attributes enables the biofilm to persist through harsh environmental conditions, including antimicrobial induced stress and to resist sanitization efforts. Because of these features, biofilms can rapidly disseminate across numerous surfaces and as they establish, become challenging to remove. This is a particular issue for the food industry as processing plants offer favorable conditions for biofilm formation …

Floxed-Cassette Allelic Exchange Mutagenesis Enables Markerless Gene Deletion In Chlamydia Trachomatis And Can Reverse Cassette-Induced Polar Effects, Gabrielle Keb, Robert Hayman, Kenneth A. Fields

Microbiology, Immunology, and Molecular Genetics Faculty Publications

As obligate intracellular bacteria, Chlamydia spp. have evolved numerous, likely intricate, mechanisms to create and maintain a privileged intracellular niche. Recent progress in elucidating and characterizing these processes has been bolstered by the development of techniques enabling basic genetic tractability. Florescence-reported allelic exchange mutagenesis (FRAEM) couples chromosomal gene deletion with the insertion of a selection cassette encoding antibiotic resistance and green fluorescent protein (GFP). Similar to other bacteria, many chlamydial genes exist within polycistronic operons, raising the possibility of polar effects mediated by insertion cassettes. Indeed, FRAEM-mediated deletion of Chlamydia trachomatis tmeA negatively impacts the expression of tmeB. We …

Synthesis And Characterization Of Targeted Bar Encapsulated Polylactic-Co-Glycolic Acid Nanoparticles To Inhibit Porphyromonas Gingivalis Biofilm Formation., Ranjith Radha Krishnan

Electronic Theses and Dissertations

Periodontal disease is one of the most prevalent infectious diseases worldwide. Between 30-50% of the global adult population suffers from periodontal disease. Some form of periodontitis is present in 46% of American adults, corresponding to annual expenditures in excess of 14 billion dollars for treatment and prevention. Current treatments for periodontal diseases involve mechanical removal of plaque, correction of risk factors, gingival surgery and/or antibiotic therapy. To our knowledge there is no effective therapeutic approach that aims to limit pathogen colonization of the oral biofilm or re-colonization after treatment. Interaction of the pathogen Porphyromonas gingivalis with oral streptococci is critical …

Insights Into The Reactivation, Regulation And Essentiality Of Oxidative Protein Folding Pathways In Actinobacteria, Belkys Sanchez

Dissertations and Theses (Open Access)

Accurate disulfide bond formation is important for proper folding, stability and function of exported proteins. The process of disulfide bond formation, termed oxidative protein folding, is catalyzed by thiol-disulfide oxidoreductase enzymes. Oxidative protein folding pathways influence processes essential for bacterial physiology and pathogenicity. In the Gram-positive actinobacterial pathogens Actinomyces oris and Corynebacterium diphtheriae oxidative protein folding is catalyzed by the primary thiol-disulfide oxidoreductase MdbA. MdbA is required for assembly of adhesive pilus, which mediate receptor-dependent bacterial interactions, or coaggregation, in A. oris. In the first part of this dissertation, I identify components of the electron transport chain (ETC) required for …

Author Correction: Herbivorous Turtle Ants Obtain Essential Nutrients From A Conserved Nitrogen-Recycling Gut Microbiome (Nature Communications (2018), Yi Hu, Jon G. Sanders, Piotr Łukasik, Catherine L. D'Amelio, Mark P. Schotanus, John T. Wertz

University Faculty Publications and Creative Works

The originally published version of the Supplementary Information file associated with this Article contained an error in Supplementary Figure 3. Panel b was inadvertently replaced with a duplicate of panel a. The error has now been fixed and the corrected version of the Supplementary Information PDF is available to download from the HTML version of the Article.