Microbiology Commons^™

Modeling Beta-Traces For Beta-Barrels From Cryo-Em Density Maps, Dong Si, Jing He

Computer Science Faculty Publications

Cryo-electron microscopy (cryo-EM) has produced density maps of various resolutions. Although ά-helices can be detected from density maps at 5-8 angstrom resolutions, β-strands are challenging to detect at such density maps due to close-spacing of β-strands. The variety of shapes of β-sheets adds the complexity of β-strands detection from density maps. We propose a new approach to model traces of β-strands for β-barrel density regions that are extracted from cryo-EM density maps. In the test containing eight β-barrels extracted from experimental cryo-EM density maps at 5.5 angstrom-8.25 angstrom resolution, StrandRoller detected about 74.26% of the amino acids in the β-strands …

Comparing An Atomic Model Or Structure To A Corresponding Cryo-Electron Microscopy Image At The Central Axis Of A Helix, Stephanie Zeil, Julio Kovacs, Willy Wriggers, Jing He

Computer Science Faculty Publications

Three-dimensional density maps of biological specimens from cryo-electron microscopy (cryo-EM) can be interpreted in the form of atomic models that are modeled into the density, or they can be compared to known atomic structures. When the central axis of a helix is detectable in a cryo-EM density map, it is possible to quantify the agreement between this central axis and a central axis calculated from the atomic model or structure. We propose a novel arc-length association method to compare the two axes reliably. This method was applied to 79 helices in simulated density maps and six case studies using cryo-EM …

การยับยั้งการเจริญและการผลิตอะฟลาทอกซินของ Aspergillus Flavus ในไซเลจข้าวโพดโดยใช้ยีสต์และแล็กติกแอซิดแบคทีเรียปฏิปักษ์, ทรรศภรณ์ รุ่งชัยวัฒนกุล

Chulalongkorn University Theses and Dissertations (Chula ETD)

วัตถุประสงค์ของงานวิจัยนี้เพื่อศึกษาความสามารถของยีสต์และแล็กติกแอซิดแบคทีเรียปฏิปักษ์ในการยับยั้งการเจริญและการผลิตอะฟลาทอกซินรวมของ Aspergillus flavus บนจานอาหารเลี้ยงเชื้อและในไซเลจข้าวโพด และเพื่อหาปริมาณความเข้มข้นและอัตราส่วนของแล็กติกแอซิดแบคทีเรียและยีสต์ผสมที่ให้ผลการยับยั้งสูงสุดในไซเลจข้าวโพด โดยเริ่มจากการทดสอบประสิทธิภาพของยีสต์ (Wickerhamomyces anomalus MSCU 0652 และ Kluyveromyces marxianus MSCU 0655) และแล็กติกแอซิดแบคทีเรีย (Lactobacillus casei AN2 และ Lactobacillus paracasei AN3) ในการยับยั้งการเจริญและการผลิตอะฟลาทอกซินของ A. flavus บนอาหารเลี้ยงเชื้อ พบว่า จุลินทรีย์ปฏิปักษ์ที่ใช้ทดสอบทั้งหมดให้ผลการยับยั้งการเจริญของราค่อนข้างต่ำ (10-20 เปอร์เซ็นต์) อย่างไรก็ตาม ยีสต์ผสมระหว่าง W. anomalus MSCU 0652 และ K. marxianus MSCU 0655 และ L. paracasei AN3 แบบเดี่ยวมีประสิทธิภาพในการลดการผลิตอะฟลาทอกซินรวมสูงสุด (43.25 และ 35.64 เปอร์เซ็นต์ ตามลำดับ) ดังนั้น จึงนำยีสต์ผสมและ L. paracasei AN3 มาทดสอบความสามารถในการยับยั้งการเจริญและการผลิตอะฟลาทอกซินรวมของ A. flavus ในไซเลจข้าวโพดปลอดเชื้อและไซเลจข้าวโพดร่วมกับจุลินทรีย์ประจำถิ่น พบว่า การใช้ L. paracasei AN3 ร่วมกับยีสต์ผสมระหว่าง W. anomalus MSCU 0652 และ K. marxianus MSCU 0655 สามารถยับยั้งการเจริญและลดปริมาณอะฟลาทอกซินรวมของราได้ดีทั้งในไซเลจข้าวโพดปลอดเชื้อและไซเลจข้าวโพดที่หมักร่วมกับจุลินทรีย์ประจำถิ่น จากนั้น เมื่อทดสอบความเข้มข้นและอัตราส่วนของ L. paracasei AN3 ร่วมกับยีสต์ผสมระหว่าง W. anomalus MSCU 0652 และ K. marxianus MSCU 0655 ที่เหมาะสม พบว่า การเติม L. paracasei AN3 ที่ความเข้มข้นมากกว่ายีสต์ผสม (10⁸:10⁶) …

Bioelectrohydrogenesis And Inhibition Of Methanogenic Activity In Microbial Electrolysis Cells - A Review, Rengasamy Karthikeyan, Ka Yu Cheng, Ammaiyappan Selvam, Arpita Bose, Jonathan W.C. Wong

Biology Faculty Research

Microbial electrolysis cells (MECs) are a promising technology for biological hydrogen production. Compared to abiotic water electrolysis, a much lower electrical voltage (~0.2V) is required for hydrogen production in MECs. It is also an attractive waste treatment technology as a variety of biodegradable substances can be used as the process feedstock. Underpinning this technology is a recently discovered bioelectrochemical pathway known as "bioelectrohydrogenesis". However, little is known about the mechanism of this pathway, and numerous hurdles are yet to be addressed to maximize hydrogen yield and purity. Here, we review various aspects including reactor configurations, microorganisms, substrates, electrode materials, and …

Biochemical, Structural, And Drug Design Studies Of Norovirus And Zika Virus Proteases, Ben Kuiper

Wayne State University Dissertations

Noroviruses, which are the leading cause of acute gastroenteritis, cause an estimated 677 million infections and 213,000 deaths each year worldwide. Noroviruses are classified into seven genogroups (GI-GVII); GI, GII, and GIV have been shown to be infectious in humans. However, GII noroviruses cause the majority of outbreaks (89%). No pharmacologic treatment or vaccine currently exists to treat or prevent norovirus infections.

Recently, the development of a norovirus replicon system, a murine model of norovirus infection, and the development of a biochemical protease assay have allowed for the design and development of norovirus inhibitors. However, the replicon and biochemical assay …

Investigation Into Roseburia Intesinalis For Optimal Growth And Survivability Conditions For Potential Probiotic Use, Lisa Rana Felczak

Wayne State University Theses

Obesity and diabetes is an epidemic of increasing concern. Certain novel bacteria have been found to be an aid in reversing some of the mechanisms associated. This study focused on investigating the optimal stability conditions for R.intestinalis that can associate with an increase in growth. First, environmental conditions were tested to find the optimal conditions associated with each. Once growth conditions were found, generation time was calculated and various prebiotics were used to investigate a potential for additional growth. Next, common antibiotics were tested to see if the R.intestinalis could still show growth when exposed. Large batches of R.intestinalis were …

Human Cytomegalovirus Cytoplasmic Virion Assembly Complex: Structure In Vivo And Role Of Pul103 In Its Biogenesis, Ma Christina Raye Lim

Wayne State University Theses

Human Cytomegalovirus (HCMV) is a linear, double stranded DNA virus that causes severe disease in the immunocompromised, and is one of the common cause of congenital disease. Antivirals that are currently available for treatment target the DNA replication of the virus cycle, and are highly toxic. Finding new drug targets, such as proteins responsible for virion assembly and egress, would help to alleviate the disease burden.

HCMV remodels the host cell to form a structure called the cytoplasmic virion assembly complex (cVAC), a site of virion maturation and egress. The first objective of this work is to study the structure …

The Potential Stimulation Of C. Minuta Growth By Various Prebiotics, And Its Sensitivity To Various Antibiotics, Maria Elena Hakim

Wayne State University Theses

Gut microbiota play a crucial role in maintaining intestinal health and integrity; a feature that is both heritable, as well as affected by the environment and lifestyle. Probiotics are supplements containing live microorganisms that act in a similar manner to gut microflora, and maintain a balance in the latter. C. minuta is a novel bacterium in the gut that was found to be associated with reduction in body weight and adiposity. The aim of this study was to determine the possible effects of different prebiotics on C. minuta growth, and the survival of C. minuta in response to different antibiotics. …

Investigating The Sources And Dynamics Of Escherichia Coli In A Missouri Ozarks Watershed, Kaleb Bassett

Masters Theses

"Escherichia coli, an intestinal bacterium, can serve as an indication of the presence of pathogenic microorganisms in water systems used by humans for recreation, agriculture, or drinking water. Many aquatic systems in the United States exceed the E. coli standard, set by the Environmental Protection Agency, for safe drinking water and recreational use. During 2016, a water sampling program was established in the Mill Creek watershed, a rural watershed located near the city of Newburg in Phelps County, Missouri. Water samples were collected before, during, and after storms throughout the year to examine the relationship between E. coli …

Using Rainbow Trout Cell Lines As A Model For Understanding The Innate Anti-Fv3 Immune Response, Graeme Robert Jones Lisser

Theses and Dissertations (Comprehensive)

Ranavirus infections are on the rise and have been implicated in numerous species die-offs across the globe. Frog virus 3 (FV3) is the type-species of the genus, yet the immune mechanisms governing susceptibility remain poorly understood. Arguably the most important immune response to infection is the type I interferon (IFN) response. Type I IFNs trigger an “antiviral state” in host cells via the production of numerous interferon-stimulated genes (ISGs) that act to inhibit virus replication in various way, including the induction of apoptosis. Apoptosis is an important antiviral defense mechanism to limit virus replication within infected cells. This study employed …

Media Optimization, Scale-Up And Repeated Fed-Batch Operations For The Production Of 1,3-Propanediol From Glycerol By Halanaerobium Hydrogeniformans, Shivani Kalia

Masters Theses

"The development of renewable energy sources, such as biofuels, is of great interest in today's world due to depletion of fossil fuels and concerns about climate change. The production of the main by-product, crude glycerol, in biodiesel production presents an opportunity for the production of industrially relevant commodities. Crude glycerol in biodiesel waste is highly impure and possesses high salt concentrations and alkalinity, making it infeasible for direct industrial utilization. Moreover, current glycerol purification methods are highly cost-intensive, necessitating a search for cost-effective approaches that are feasible to employ. Genome data analysis of Halanaerobium hydrogeniformans, revealed the metabolic capability …

Phenotyping Temperature-Sensitive Coronaviruses, Amani Eddins

Master's Theses

Coronaviruses (CoVs) can cause a range of symptoms; from a mild common cold to life threatening acute respiratory distress syndrome (ARDS) upon infection. These emerging viruses have the ability to be highly pathogenic and detrimental to the human population. Two prime examples of CoV emergence, SARS-CoV (Severe Acute Respiratory Syndrome) and MERS-CoV, (Middle Eastern Respiratory Syndrome), which exhibits the pandemic potential of emerging CoVs that gain human tropism. Given the increasing potential of an emerging CoV outbreak there is a state of urgency to develop vaccines that will help protect the human population against current and future circulating strains. The …

Utilizing Genetic Techniques To Identify Amino Acids Within The Putative Glycosyltransferase Sypq That Are Essential For Its Role In Biofilm Formation By Vibrio Fischeri, Mary Kathryn Flaherty

Master's Theses

The polysaccharide component of the V. fischeri biofilm is produced by proteins encoded by the symbiosis polysaccharide (syp) locus. The syp locus encodes 18 genes, six of which are putative glycosyltransferases (GTs). One of these GTs, sypQ, encodes a putative family 2 glycosyltransferase (GT-2). The mechanism by which SypQ facilitates biofilm formation is not yet understood. To uncover which specific residues are essential for the function of SypQ, I utilized Bioinformatics, site-directed mutagenesis, and random mutagenesis. The Bioinformatics identified putative GT-2 motifs in the SypQ primary sequence. The mutagenesis (both site-directed and random), identified five residues (D95, D151, S153, D236, …

Optimizing Clean Catch Urine Collection And Its Applications In Urinary Microbiome Studies, Danielle Johansen

Master's Theses

Clean catch was developed before the advancement of more sensitive assays for culturing urinary bacteria. I reassessed clean catch, endeavoring to optimize this method. Periurethral swabs and voided urines were routinely collected, while analyzing different aspects of the method. I determined that midstream urine contained the least amount of vulvo-vaginal contamination and that the time of collection did not impact the results. I also determined that the use of antiseptic wipes prior to void increased the level of vulvo-vaginal contamination. A small cohort of females collected daily urines over a 17-day period and kept a strict alcohol diary. Females who …

Characterization Of Inhibitory Molecules Produced By Lactobacillus Crispatus, Giuseppe Anthony Pistone

Master's Theses

Lactobacillus species are widely accepted as beneficial bacteria of the human microbiota1-8. Lactobacilli spp. are well documented to inhibit pathogens by production and secretion of hydrogen peroxide (H2O2), organic acids, and/or proteinaceous bacteriocins into their environment. Most research attributes bactericidal activity of cell free supernatant (CFS) to H2O2 and/or lactic acid. Here, I demonstrate that CFS from a clinical isolate of Lactobacillus crispatus contains a molecule(s) that inhibits uropathogenic Escherichia coli (UPEC) colony formation independently of H2O2 and organic acids. Physiologic concentrations of H2O2 and organic acids produced by L. crispatus do not inhibit UPEC colony formation. Incubation of UPEC …

Metabolic Characteristics Of Macrophage Activation With Phenotype Microarrays, Tanya Kathryn D'Souza

Theses

Inflammation is a natural protective response and is characterised by the activation of numerous immune cells, including macrophages which can release a variety of inflammatory mediators. Macrophages play a flexible role in the initiation and effector phases of the immune response and change their behaviour to respond to environmental stimuli. The main objectives in this study were to create and characterise different macrophage behaviours and employ a novel metabolic characterisation platform the Phenotype Microarray^TM to attribute additional characteristics to the currently well recognised phenotypes. Five activated macrophage states were demonstrated and characterised. Unactivated macrophages (MO) demonstrated undetectable levels of …

Effects Of Myrrh On Hsv-1 Using Plaque Assay, Badrieah Mohammad Alamri

Browse all Theses and Dissertations

Herpes simplex virus type 1 (HSV-1) is a highly infective human pathogen which infects a wide range of population in North America and worldwide. HSV-1 infection has two phases, lytic and latent. Recurrence of HSV-1 is a major challenge to clinicians to control the infection especially in immune depleted individuals. Acyclovir (ACV) is an antiviral drug used to treat HSV-1 infection. Low solubility of ACV in water, mutation of viral thymidine kinase, and mutation of viral DNA polymerase are major problems that cause usage limitations of ACV. Myrrh has been used as an analgesic and anti-inflammatory natural product in middle …

A Nutrient-Regulated Cyclic Diguanylate Phosphodiesterase Controls Clostridium Difficile Biofilm And Toxin Production During Stationary Phase, Erin B. Purcell, Robert W. Mckee, David S. Courson, Elizabeth M. Garrett, Shonna M. Mcbride, Richard E. Cheney, Rita Tamayo

Chemistry & Biochemistry Faculty Publications

The signaling molecule cyclic diguanylate (c-di-GMP) mediates physiological adaptation to extracellular stimuli in a wide range of bacteria. The complex metabolic pathways governing c-di-GMP synthesis and degradation are highly regulated, but the specific cues that impact c-di-GMP signaling are largely unknown. In the intestinal pathogen Clostridium difficile, c-di-GMP inhibits flagellar motility and toxin production and promotes pilus-dependent biofilm formation, but no specific biological functions have been ascribed to any of the individual c-di-GMP synthases or phosphodiesterases (PDEs). Here, we report the functional and biochemical characterization of a c-di-GMP PDE, PdcA, 1 of 37 confirmed or putative c-di-GMP metabolism proteins …

Fractionation And Characterization Of Lignin Streams From Genetically Engineered Switchgrass, Enshi Liu

Theses and Dissertations--Biosystems and Agricultural Engineering

Development of biomass feedstocks with desirable traits for cost-effective conversion is one of the main focus areas in biofuels research. As suggested by techno-economic analyses, the success of a lignocellulose-based biorefinery largely relies on the utilization of lignin to generate value-added products, i.e. fuels and chemicals. The fate of lignin and its structural/compositional changes during pretreatment have received increasing attention; however, the effect of genetic modification on the fractionation, depolymerization and catalytic upgrading of lignin from genetically engineered plants is not well understood. This study aims to fractionate and characterize the lignin streams from a wild-type and two genetically engineered …

Role Of Intracellular Growth During The Gastrointestinal Stage Of Listeria Monocytogenes Infection, Grant Steven Jones

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Listeria monocytogenes is a facultative intracellular bacterium that causes foodborne disease in humans. L. monocytogenes invade the gut mucosa and then disseminate, causing systemic infections associated with high mortality rates in immunocompromised individuals. It is unknown how L. monocytogenes traffic to the mesenteric lymph nodes, which represent an important bottleneck for systemic spread. In addition, little is known about the gastrointestinal stage of infection due to the general resistance of mice to oral infection with L. monocytogenes. Our laboratory developed a novel foodborne mouse model of listeriosis utilizing a murinized strain of L. monocytogenes to investigate the gastrointestinal stage …