Microbiology Commons^™

Type Vi Secretion System Mutations Reduced Competitive Fitness Of Classical Vibrio Cholerae Biotype, Benjamin Kostiuk, Francis J. Santoriello, Laura Diaz-Satizabal, Fabiana Bisaro, Kyung-Jo Lee, Anna N. Dhody, Daniele Provenzano, Daniel Unterweger, Stefan Pukatzki

Publications and Research

The gram-negative bacterium Vibrio cholerae is the causative agent of the diarrhoeal disease cholera and is responsible for seven recorded pandemics. Several factors are postulated to have led to the decline of 6th pandemic classical strains and the rise of El Tor biotype V. cholerae, establishing the current 7th pandemic. We investigated the ability of classical V. cholerae of the 2nd and 6th pandemics to engage their type six secretion system (T6SS) in microbial competition against non-pandemic and 7th pandemic strains. We report that classical V. cholerae underwent sequential mutations in T6SS genetic determinants that initially exposed 2nd pandemic strains …

Risk Based Simulations Of Sporeformers Population Throughout The Dairy Production And Processing Chain: Evaluating On-Farm Interventions In Nebraska Dairy Farms, Rhaisa A. Crespo Ramírez

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

Sporeformer bacteria are ubiquitous in the farm environment. These bacteria produce enzymes that negatively affect the quality of dairy products representing a problem for the dairy industry. Two major issues associated with high levels of sporeformers in raw milk are shelf-life reduction of fluid milk and market limitations for milk powder. Specific attention has been given to the contamination of milk powders with sporeformers due to their ability to survive pasteurization and milk powder processing conditions. Hence, the control of sporeformers is crucial to benefit the whole dairy industry. Researchers have suggested that certain management practices could decrease sporeformers in …

The Temperature-Dependent Conformational Ensemble Of Sars-Cov-2 Main Protease (Mpro), Ali Ebrahim, Blake T. Riley, Desigan Kumaran, Babak Andi, Martin R. Fuchs, Sean Mcsweeney, Daniel A. Keedy

Publications and Research

The COVID-19 pandemic, instigated by the SARS-CoV-2 coronavirus, continues to plague the globe. The SARS-CoV-2 main protease, or M^pro, is a promising target for development of novel antiviral therapeutics. Previous X-ray crystal structures of M^pro were obtained at cryogenic temperature or room temperature only. Here we report a series of high-resolution crystal structures of unliganded M^pro across multiple temperatures from cryogenic to physiological, and another at high humidity. We interrogate these datasets with parsimonious multiconformer models, multi-copy ensemble models, and isomorphous difference density maps. Our analysis reveals a temperature-dependent conformational landscape for M^pro, including …

Complete Genome Sequence Of The Pantoea Phage Ah07, Gregory P. Krukonis, Sam J. Roth, Veronique A. Delesalle

Biology Faculty Publications

Bacteriophages of the phyllosphere have not been extensively described, despite their role in bacterial communities on this plant organ. Here, we describe a temperate Pantoea phage, AH07, that was isolated from the leaves of horse chestnut trees. The 37,859-bp linear double-stranded DNA genome contains 58 putative genes, including an integration cassette.

Complete Genome Sequences Of Four Phages Of The Horse Chestnut Phyllosphere, Gregory P. Krukonis, Sam J. Roth, Veronique A. Delesalle

Biology Faculty Publications

Bacteriophages play important roles in determining bacterial communities, including plant microbiota. Here, we describe four lytic phages, three Siphoviridae and one Podoviridae, isolated from four different bacterial species found on the leaves of horse chestnut trees. Their double-stranded DNA (dsDNA) genomes range from 39,095 to 46,062 bp and contain 51 to 70 genes.

Genome Sequences Of Erwinia Phyllophages Ah04 And Ah06, Gregory P. Krukonis, Sam J. Roth, Veronique A. Delesalle

Biology Faculty Publications

Although crucial in shaping bacterial communities, few bacteriophages of the phyllosphere have been described. We provide genome data for two Myoviridae phages, AH04 and AH06, isolated on Erwinia billingiae strains. AH04 shares limited genetic similarity with previously described phages, while AH06 shares over 75% similarity with various Erwinia phages.

Monoclonal Antibodies Protect Aged Rhesus Macaques From Sars-Cov-2-Induced Immune Activation And Neuroinflammation, Anil Verma, Chase E. Hawes, Yashavanth Shaan Lakshmanappa, Jamin W. Roh, Brian A. Schmidt, Joseph Dutra, William Louie, Hongwei Liu, Zhong Min Ma, Jennifer K. Watanabe, Jodie L. Usachenko, Ramya Immareddy, Rebecca L. Sammak, Rachel Pollard, J. Rachel Reader, Katherine J. Olstad, Lark L. Coffey, Pamela A. Kozlowski, Dennis J. Hartigan-O'Connor, Michel Nussenzweig

School of Graduate Studies Faculty Publications

Anti-viral monoclonal antibody (mAb) treatments may provide immediate but short-term immunity from coronavirus disease 2019 (COVID-19) in high-risk populations, such as people with diabetes and the elderly; however, data on their efficacy in these populations are limited. We demonstrate that prophylactic mAb treatment blocks viral replication in both the upper and lower respiratory tracts in aged, type 2 diabetic rhesus macaques. mAb infusion dramatically curtails severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-mediated stimulation of interferon-induced chemokines and T cell activation, significantly reducing development of interstitial pneumonia. Furthermore, mAb infusion significantly dampens the greater than 3-fold increase in SARS-CoV-2-induced effector CD4 …

Assessment Of Bacteriological Quality Of Drinking Water In Some Primary And Secondary Schools In Mukalla City-Hadhramout/Yemen, Eidha Ali Bin Hameed, Khaled Saleh Bin Alshikh Bubkr

Hadhramout University Journal of Natural & Applied Sciences

Assessment of faecal contamination and detection enumeration of coliforms and other microorganisms in water is one of the measurements to determine the hygienic quality of water. This study aimed to assess the drinking water in some primary and secondary schools in Mukalla city-Hadhramout/Yemen to estimate the bacterial contamination of drinking water and its safety to the public. The water samples were studied for bacteriological analysis in which was inoculated into culture media using two methods, the presumptive test for the most probable number (MPN) and confirmatory test for bacterial identification. Also, some physiochemical properties of water such as temperature, total …

Contact Normalization And The Role Of Maackia Amurensis Seed Lectin As A Novel Chemotherapeutic And Antiviral Agent, Stephanie A. Sheehan

Graduate School of Biomedical Sciences Theses and Dissertations

Cells communicate with each other to coordinate tissue function and homeostasis. Diseases including cancer, arthritis, and acute respiratory disease syndrome (ARDS) require a breakdown in this intercellular communication. For example, cancer progression is suppressed by junctional communication between nontransformed and transformed cells. This process is called contact normalization. Junctional communication must be disrupted to enable transformed cells to grow into malignancies. However, the junctions and mechanisms by which nontransformed cells normalize cell behavior have not been clearly defined. My project aimed to identify junctions and elucidate mechanisms underlying contact normalization. We discovered that cadherins, specifically N-cadherin, form junctions that enable …

College Of Natural Sciences Scholarship Brunch Program, November 6th 2021, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

This is the program for the first annual College of Natural Sciences Scholarship Brunch, held on November 6th, 2021 at McCrory Gardens.

College Of Natural Sciences Newsletter, November 2021, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 2, Issue 11

Page 1 Dean's Message
Page 2 Awards & Recognition
Page 3 Media Coverage of CNS
Page 4 2021 Day of Scholars
Page 5 Astronomy Outreach
Page 6 SDSU Faculty & Students Host American Society for Microbiology Annual Conference
Page 7 Scholarship Brunch
Page 8 Open PRAIRIE Data, SI Final Exam Review Sessions
Page 9 Aamlid Family Anatomy Lab Photos

Spotted Salamander Egg Masses Exhibit A Unique Internal Microbiome In Relation To Their Environment, Elizabeth Leonard

Senior Honors Theses

Microbial studies have led to various ecological and medicinal discoveries. Amphibian eggs, like those of Ambystoma maculatum, exhibit natural resistance to bacterial invasion that may be microbiome related. The purpose of this research was to sequence the external and internal microbiome of A. maculatum egg masses and compare with the environmental microbiome. It was hypothesized that the external and internal microbiome would bear more similarity to each other than the water. A significant difference was observed between the microbiome of the inside surface of the egg mass and the water but not the outside surface of the egg and …

Dietary Fiber Utilization In The Gut: The Role Of Human Gut Microbes In The Degradation And Consumption Of Xylose-Based Carbohydrates, Elizabeth Drey

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

Xylans are a family of xylose-based polysaccharides naturally present in fruits, vegetables, and cereal grains. Resistant to digestion by host enzymes, xylans reach the large intestine intact, where they are utilized by members of the gut microbiome. They are initially hydrolyzed by primary degraders that utilize extracellular xylanases to cleave xylan into smaller oligomers. These xylooligosaccharides (XOS) can then either be further hydrolyzed by primary degraders or can cross-feed secondary consumers, including Bifidobacterium. While several Bifidobacterium species have metabolic systems for XOS, studies have shown these species grow poorly on longer XOS and xylan substrates. In this thesis, …

Microbiota From Specific Pathogen-Free Mice Reduces Campylobacter Jejuni Chicken Colonization, Ayidh Almansour, Ying Fu, Tahrir Jatli Alenezi, Mohit Bansal, Bilal Alrubaye, Hong Wang, Xiaolun Sun

Poultry Science Faculty Publications and Presentations

Campylobacter jejuni, a prevalent foodborne bacterial pathogen, is mainly transmitted from poultry with few effective prevention approaches. In this study, we aimed to investigate the role of microbiota on C. jejuni chicken colonization. Microbiota from specific pathogen-free (SPF) mouse stools were collected as SPF-Aerobe and SPF-Anaerobe. Birds were colonized with SPF-Aerobe or SPF-Anaerobe at day 0 and infected with C. jejuni AR101 at day 12. Notably, C. jejuni AR101 colonized at 5.3 and 5.6 log(10) C. jejuni CFU/g chicken cecal digesta at days 21 and 28, respectively, while both SPF-Aerobe and SPF-Anaerobe microbiota reduced pathogen colonization. Notably, SPF-Aerobe and SPF-Anaerobe …

Microbial Dark Matter: Culturing The Uncultured In Search Of Novel Chemotaxonomy, Sarah J. Kennedy

USF Tampa Graduate Theses and Dissertations

Although <1% of environmental isolates can be cultured, insights into the culturable fraction refine future techniques to unlock the cryptic biodiversity. This cryptic biodiversity is omnipresent within culture-independent surveys of environmental bacterial populations. Subsequently, these elusive organisms are termed “microbial dark matter” due to the intrigue surrounding their potential taxonomic and biosynthetic impacts. To this end of investigating bacterial-specific dark matter, we employed high-throughput culturing techniques to examine Gulf of Mexico sediments and sponges for chemotaxonomically important bacteria. Through stepwise implementation of permissive and selective recovery techniques, we succeeded in recovering over 150 unique bacterial isolates. We observed several isolates that pose as chemotaxonomically interesting, including several strains that belong to critical bioremediation taxa. In addition to these biotechnological-amenable isolates, we have also succeeded in culturing taxa historically attributed with antibacterial discoveries. One such isolate was a previously sponge-associated organism belonging to the rarely cultured Verrucosispora genus. Through extensive comparative genomics, we identified it as a novel species and subsequently named it Verrucosispora sioxanthis sp. nov. with the published genome serving as a resource for continued microbial dark matter investigations. Following continued passaging of the organism, we observed improved growth, biomass, and liquid growth dispersal within each increasingly sub-passaged generation of the isolate. As such, the laboratory attenuation, or domestication, of the organism warranted in-depth whole genomic analyses to generate insight into the increased laboratory sustainability. Through phenotypically-guided bioinformatics, we determined that the domestication was mediated through genome-wide selective pseudo- or non-pseudogenization of genes. As the previously sponge-associated organism evolved with the selection pressures of the static laboratory, we demonstrate that isolate effectively underwent genomic atrophy to resolve into a largely stable, sustainable laboratory-domesticated strain. Collectively, our chemotaxonomic discovery pipeline expands on the culturable bacterial biodiversity and ultimately provides a previously uncultured model organism for initial forays into resolving the microbial dark matter knowledge gap.

Investigation Of An Alternative Protocol For The Production Of Sars-Cov-2 Antigenic Proteins, Nichole Ninaltowski

USF Tampa Graduate Theses and Dissertations

With the COVID-19 pandemic showing no signs of slowing down, large-scale antigenic protein production is still needed for surveillance using serologic assays. From screening to vaccines to biotherapeutics, being able to produce the proteins for these assays is essential; however, the current gold standard method for producing SARS-CoV-2 spike proteins is prohibitively expensive for most research groups.

Alternative methods of transfecting mammalian cells to produce recombinant proteins that are relatively inexpensive have been used for years. Unlike the expensive, commercially available lipid-based methods, other established methods such as polyethyleneimine (PEI), are considerably easier, and cheaper to meet the needs of …

A Functional Characterization Of The Omega (Ω) Subunit Of Rna Polymerase In Staphylococcus Aureus, Shrushti B. Patil

USF Tampa Graduate Theses and Dissertations

In bacteria, RNA polymerase (RNAP) is a well-characterized and highly conserved multi-subunit enzyme complex responsible for transcription of DNA into RNA. The ω subunit (rpoZ/RpoZ), one of the smaller accessory subunits of RNAP, is often overlooked and under-studied, however, particularly in Gram-positive species. We have previously shown that deleting ω impacts the integrity of RNA polymerase in S. aureus, especially the β' subunit, and alters preference of the core enzyme for sigma factors, skewing heavily towards σB instead of the housekeeping σ factor. Consequently, this causes deregulation of myriad transcriptional processes, strongly rewiring gene expression circuits, and ultimately impairing the …

Prevalence And Multidrug Resistance Pattern Of E. Coli Among Urinary Tract Infection Patients In Tertiary Care Hospital Of Multan, Hubza Ruatt Khan, Mehvish Javeed, Asghar Javed, Nisma Farooq

Journal of Bioresource Management

Urinary Tract Infection is alarming problem worldwide due to the intensity of antimicrobial resistance. Escherichia coli is the most predominant organism in UTI. This study was planned to evaluate demographic parameters, the prevalence of E. coli, and antimicrobial resistance patterns among E. coli isolates from UTI patients in Nishtar Hospital of Multan from January to June 2018. A total of 350 mid-stream urine samples were collected from different patients having age group from 25 to 60 years and processed by standard laboratory procedures. Out of 350 samples, 100 samples were observed as critical bacteremia. Escherichia coli and Klebsiella …

Biological Characterization Of Plasmodium Falciparum Mitochondrial Heat Shock Protein Pfhsp70-3: Possible Involvement In Malaria Pathogenesis, David O. Nyakundi, Aileen Boshoff

Tanzania Journal of Science

Malaria remains a global health burden accounting for many deaths and illnesses in sub-Saharan Africa notwithstanding many decades of research on the disease. P. falciparum, the causative agent of the most fatal form of malaria, expresses a repertoire of heat shock proteins (Hsp) that cushion the parasite against heat shocks as it shuttles between extreme temperatures in human and mosquito vector hosts. By so doing, such proteins promote parasite’s cytoprotection, survival and pathogenesis. Heat shock proteins are named according to their molecular weights and there are six P. falciparum Hsp70 (PfHsp70) found in various cell compartments with mitochondrial putative PfHsp70-3. …

A Mathematical Analysis Of An In-Vivo Ebola Virus Transmission Dynamics Model, Seleman Ismail, Adeline Peter Mtunya

Tanzania Journal of Science

Ebola virus (EBOV) infection is a hemorrhagic and hazardous disease, which is among the most shocking threats to human health causing a large number of deaths. Currently, there are no approved curative therapies for the disease. In this study, a mathematical model for in-vivo Ebola virus transmission dynamics was analyzed. The analysis of the model mainly focused on the sensitivity of basic reproductive number,  pertaining to the model parameters. Particularly, the sensitivity indices of all parameters of  were computed by using the forward normalized sensitivity index method. The results showed that a slight change in the infection rate immensely influences …