Microbiology Commons^™

Functional Analysis Of Glutathione S-Transferase From The Extremophile Halothece Sp. Pcc7418, Chananwat Kortheerakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Glutathione S-transferase (GST) are a set of multifunctional enzymes encoded by large gene families. It has been functionally demonstrated that GSTs play vital roles in cellular detoxification, regulation of redox-dependent process, and stress responses. Although the GST gene family has been extensively studied across taxa, the function of the GST genes in primordial oxygenic phototrophs such as cyanobacteria is poorly understood. In this thesis, GSTs from extremophilic cyanobacterium Halothece sp. PCC7418 (hereafter Halothece GSTs) were identified and functionally characterized. The genome-based analysis showed that there were four GSTs in Halothece 7418 (GST_0647, GST _0729, GST _1478, and GST _3557). Phylogenetic …

The Host Gatekeeper: Using The Flagellar Pathway To Understand Symbiont Host Adaptation, Adam R. Pollio

Graduate Theses, Dissertations, and Problem Reports (ETD)

The acquisition of microbial partners is a strategy used by a diverse group of arthropods to overcome ecological barriers that might normally make certain niches uninhabitable. The unique phylogenetic opportunities attainable from the natural experiment of the Sodalis-allied clade allow for better understanding of how molecular structures evolve through time. Here, we focus on the evolution of the flagellar synthesis pathway, due to its complexity and ability to diverge in response to ecological pressures. We used this molecular pathway and natural experiment to show that normal evolutionary outcomes associated with symbiosis (i.e., genome reduction) do not explain the predicted conservation …

Genetic And Biochemical Characterization Of Ergot Alkaloid Synthesizing Fungi And Their Symbionts, Matthew Duane Maust

Graduate Theses, Dissertations, and Problem Reports (ETD)

Ergot alkaloids are fungal tryptophan derived toxins which affect mammalian circulation and neurotransmission. These compounds are biosynthesized by a conserved genetic pathway, known as the ergot alkaloid synthesis (EAS) pathway by fungi belonging to the ascomycete families Trichocomaceae and Clavicipitaceae. Several Ipomoea species and related plants in the morning glory family harbor vertically transmitted symbiotic fungi in the genus Periglandula, also members of Clavicipitaceae, that produce ergot alkaloids. Metabolomic analysis of seeds identified a previously uncharacterized glycoside form of the pharmaceutically important ergot alkaloid, ergonovine. Several species belonging to the fungal genus Metarhizium have recently been shown to have the …

Blood Substitution Therapy Rescues The Brain Of Mice From Ischemic Damage, Xuefang Ren, Heng Hu, Imran Farooqi, James W. Simpkins

Faculty & Staff Scholarship

Acute stroke causes complex, pathological, and systemic responses that have not been treatable by any single medication. In this study, using a murine transient middle cerebral artery occlusion stroke model, a novel therapeutic strategy is proposed, where blood replacement (BR) robustly reduces infarctions and improves neurological deficits in mice. Our analyses of immune cell subsets suggest that BR therapy substantially decreases neutrophils in blood following a stroke. Electrochemiluminescence detection demonstrates that BR therapy reduces cytokine storm in plasma and ELISA demonstrates reduced levels of matrix metalloproteinase-9 (MMP-9) in the plasma and brains at different time points post-stroke. Further, we have …

Determination Of Iron-Reducing Bacterial Activities In Lake Sediments., Alexandra Kahn

Williams Honors College, Honors Research Projects

Algal blooms are growing rampantly in lacustrine systems due to an increase of phosphorus, a nutrient for algae. Phosphorus is being released into the environment causing overpopulation and eutrophication which damages the ecosystem. The availability of phosphorus is affected by the solubility of iron which is regulated through iron reducing and iron oxidizing bacteria. Phosphorus adheres to insoluble Fe(III), which prohibits algae from utilizing it, while phosphorus does not attach to soluble Fe(II) and therefore it remains available to algae. The purpose of this study was to determine how bacteria influence iron solubility and what are the ideal environmental conditions …

Development Of A Synthesis Method For O2-Releasing Compound For Microbiological Experiments, Danae Greco

Williams Honors College, Honors Research Projects

Many celestial bodies within our solar system may have habitable environments due to the presence of liquid water. Europa, one of Jupiter’s moons, may be habitable because of its liquid ocean and other potentially biologically favorable conditions. The ocean on Europa is hypothesized to contain large amounts of oxidants and low pH due to the radiolytically processed icy ocean shell. This suspected environment on Europa is similar to the composition of acid mine drainage on Earth, which can house microbial communities in environments of extreme acidity. Similar chemical reactions in Europa’s ocean may occur to produce the appropriate reduction-oxidation gradients …

The Effects Of Staining Cyanobacteria With Sytoxgreen After Lysis By Freeze-Thaw And Lysis By Ethanol, Samantha Galambos

Williams Honors College, Honors Research Projects

The purpose of this project is to find the effects of staining toxic cyanobacteria with SYTOXGreen after lysis by freeze-thaw and lysis by ethanol. This project will focus on two strains of toxic cyanobacteria known as Aphanizomenon - A. flos-aquae and Planktothrix - P. agardhii. The live and dead cells are observed under blue and red fluorescent light to show the effectiveness of each lysis. It is important that this topic is researched because it is significantly affecting our waterways and sometimes drinking water. We often see that you cannot swim in Lake Erie due to algae, more specifically, these …

Biological And Computational Studies Of The Structure And Function Of Pul103, A Human Cytomegalovirus Tegument Protein, Ashley N. Anderson

Wayne State University Dissertations

Human cytomegalovirus (HCMV) is an enveloped, single segment, double-stranded DNA virus. HCMV infection causes disease in immunocompromised (HIV patients, transplant recipients) and immunodeficient (fetuses, neonates) populations. Current treatments are effective but are either limited in use or can lead to organ damage and/or antiviral resistance, and no vaccines are available. Additional antiviral targets are needed. HCMV pUL103 is a potential antiviral target. pUL103 is a conserved herpesvirus protein present in the tegument, layer of proteins and RNA between the envelope and capsid of HCMV virions. pUL103 helps reorganize cellular secretory machinery (Golgi, endosomes) to form the cytoplasmic virion assembly compartment …

The Effects Of The Estrus Cycle On Microbiota Composition And The Opportunistic Pathogen Listeria Monocytogenes Infection Process In Murine Models, Ryan William-Thomas Donkin

Online Theses and Dissertations

In the U.S., Listeria monocytogenes accounts for less than one percent of foodborne illnesses but has a 28% mortality rate. Infection in healthy individuals causes colonization of the intestinal lumen and subclinical noninvasive listeriosis. However, translocation of L. monocytogenes across the intestinal epithelium produces invasive systemic listeriosis with central nervous system involvement. Little is known of the gastrointestinal stages of L. monocytogenes pathogenesis. Enteric pathogens such as L. monocytogenes interact directly with the host-microbiota during the gastrointestinal phase of pathogenesis. Recent research has recognized that microbiota plays a role in activating immune response and protecting against invasive pathogens. Individual host …

Non-Invasive Method For Leptin Supplementation In Zebrafish (Danio Rerio), Regan Mcnamara

Williams Honors College, Honors Research Projects

I tested the hypothesis that recombinant leptin protein can be introduced to zebrafish in vivo through non-invasive soaking in a solution containing the protein. One way to study various molecules’ effects in vivo is through intraperitoneal or intracerebroventricular injections during the embryonic or larval stage, which is invasive, difficult to administer, and can have a high mortality rate. 48 hours post fertilization (hpf) zebrafish were soaked in a His-tagged recombinant leptin protein solution at 10 nM and 100 nM concentrations (produced by Genscript). After soaking, zebrafish larvae were washed extensively to remove all recombinant protein on their exterior before homogenization. …

Comparison Of Fe(Iii) Reduction Rates By Iron-Reducing Bacteria Within Sub Muros Samples From Quadrilátero Ferrífero Iron-Ore Caves, Brazil, Summer Ellis

Williams Honors College, Honors Research Projects

Previous research investigating the speleogenesis of iron-ore caves (IOC) in the Quadrilátero Ferrífero, or “Iron Quadrangle,” of Brazil suggests that microbial iron reduction and subsequent dissolution of the surrounding Fe(III) rich rocks is responsible for cave formation. A soft intra-wall substance (sub muros) containing iron-reducing bacteria (FeRB) was discovered underneath the durable crusts of cave walls. The goal of the study was to determine if reduction rates were comparable between sub muros samples, while additionally observing how different electron donors affect microbial iron reduction. To do this, I compared Fe(III) reduction rates between sub muros samples collected from …

Pneumovirus Infections: Understanding Rsv And Hmpv Entry, Replication, And Spread, Jonathan T. Kinder

Theses and Dissertations--Molecular and Cellular Biochemistry

Pneumoviruses including human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) are significant causes of respiratory tract infections globally. Children, elderly, and immunocompromised patients are at the greatest risk for developing severe infections, which can have devastating outcomes. Although these viruses are ubiquitous with significant impacts on human health, there are no antivirals or vaccines available. The only FDA approved therapy is a monoclonal antibody for RSV, given prophylactically during the infectious season, and this treatment is only available for high risk infants. The work presented in this thesis aims to increase our understanding of how these viruses enter, replicate, and …

The Exploration Of Nanotoxicological Copper And Interspecific Saccharomyces Hybrids, Matthew Joseph Winans Phd

Graduate Theses, Dissertations, and Problem Reports (ETD)

Nanotechnology takes advantage of cellular biology’s natural nanoscale operations by interacting with biomolecules differently than soluble or bulk materials, often altering normal cellular processes such as metabolism or growth. To gain a better understanding of how copper nanoparticles hybridized on cellulose fibers called carboxymethyl cellulose (CMC) affected growth of Saccharomyces cerevisiae, the mechanisms of toxicity were explored. Multiple methodologies covering genetics, proteomics, metallomics, and metabolomics were used during this investigation. The work that lead to this dissertation discovered that these cellulosic copper nanoparticles had a unique toxicity compared to copper. Further investigation suggested a possible ionic or molecular mimicry …

Mucosa-Associated Microbiota In Barrett’S Esophagus, Dysplasia, And Esophageal Adenocarcinoma Differ Similarly Compared With Healthy Controls, Shajan Peter, Amanda Pendergraft,, William Vanderpol, Mel Wilcox, Kondal R. Kyanam Kabir Baig, Casey Morrow, Jacques Izard, Peter J. Mannon

Department of Food Science and Technology: Faculty Publications

Introduction: Alterations in the composition of the human gut microbiome and its metabolites have been linked to gut epithelial neoplasia. We hypothesized that differences in mucosa-adherent Barrett’s microbiota could link to risk factors, providing risk of progression to neoplasia.

Methods: Paired biopsies from both diseased and nonaffected esophagus (as well as gastric cardia and gastric juice for comparison) from patients with intestinal metaplasia (n = 10), low grade dysplasia (n = 10), high grade dysplasia (n = 10), esophageal adenocarcinoma (n = 12), and controls (n = 10) were processed for mucosa-associated bacteria …

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 …

The Pseudomonas Aeruginosa Interactome: Insights Into Srna-Mediated Regulatory Networks, Christine M. Van Duyn

Theses and Dissertations

Pseudomonas aeruginosa is a Gram-negative bacterium found in various environmental niches including soil, water, hospital environments, and within a broad range of hosts. It is well known for its metabolic versatility and intrinsic and acquired resistance to a variety of antimicrobial agents. Moreover, this bacterium has a remarkable ability to adapt and survive in suboptimal environments by altering its transcriptional profile in response to nutrient deprivation, changes in temperature and pH, osmotic stress, the presence of reactive oxygen species (ROS), and exposure to antibiotics and host defenses. P. aeruginosa colonizes individuals with compromised immune systems and severe burn injuries and …

Development Of A Screening Assay For Type Iii Secretion System Inhibitors And High Throughput Screening Campaign Of Inhibitors Of Prp Of Staphylococcus Aureus, Heather A. Pendergrass

Theses and Dissertations

Antibiotics inhibit the growth or survival of bacteria by targeting their essential functions.¹ Due to weaknesses in traditional antibiotics and the increasing prevalence of antibiotic resistance genes, virulence factors are being targeted for therapeutic treatment of bacterial infection.² We have developed an assay to quantify and observe type III secretion system (T3SS) activity. The type III secretion system (T3SS) is a virulence factor present in some Gram-negative pathogens including enteropathogenic and enterohemorrhagic E. coli (EPEC and EHEC, respectively),³ and others.^4–9 The T3SS between EPEC and EHEC are highly conserved and share over 90% sequence identity with …

Dna Analysis And The Postmortem Submersion Interval From The Microbiome Of Waterlogged Sus Scrofa Skeletal Remains, Claire Cartozzo

Theses and Dissertations

Following water-related deaths, soft tissue on victims’ remains may be entirely absent after a temperature dependent period of time. Due to their physical and chemical components, which protect them from environmental deterioration and biological attack, bones preserve DNA for longer periods of time. Therefore, the ability to both identify an individual and estimate the postmortem submersion interval (PMSI) may depend on DNA obtained from skeletal remains. The goals of the dissertation were to examine differences in both the degradation of skeletal DNA and the microbiome inhabiting bone in freshwater aquatic environments (e.g., Henley Lake and the James River). At each …

Use Of Pefloxacin As A Surrogate Marker To Detect Ciprofloxacin Susceptibility In Salmonella Enterica Serotypes Typhi And Paratyphi A, Safia Moin, Mohammad Zeeshan, Sidra Laiq, Ahmed Raheem, Afia Zafar

Department of Pathology and Laboratory Medicine

Objective: To determine the use of pefloxacin as a surrogate marker to detect fluoroquinolone (ciprofloxacin) susceptibility against Salmonella enterica serotypes Typhi and Paratyphi A.
Methods: The prospective, descriptive cross-sectional study was conducted at the Aga Khan University Hospital, Karachi, from September 2016 to March 2018, and comprised Salmonella Typhi and Paratyphi A isolates of blood cultures. Disk susceptibility tests and broth microdilution to test minimum inhibitory concentration were performed as per standard guidelines. Data was analysed using SPSS 21.
Results: Of the 138 isolates, 91(66%) were intermediate resistant to ciprofloxacin but were resistant to pefloxacin, 42(30%) were resistant to both …

การคัดกรองยีสต์ผลิตน้ำมันและการหาภาวะเหมาะที่สุดของการผลิตน้ำมันจากไฮโดรไลเสตของใบอ้อย, พัชราภรณ์ หุ่นดี

Chulalongkorn University Theses and Dissertations (Chula ETD)

ยีสต์ 223 ไอโซเลต ที่คัดแยกได้จาก 223 ตัวอย่าง ที่เก็บจากแหล่งธรรมชาติ 9 แห่งในประเทศไทย ถูกนำมาคัดกรองยีสต์ที่สะสมน้ำมันในเซลล์สูง การคัดกรองเบื้องต้นโดยการย้อมเซลล์ด้วยสีไนล์เรด พบว่ามียีสต์ 16 สายพันธุ์ที่มีขนาดหยดน้ำมันภายในเซลล์ใหญ่กว่าครึ่งหนึ่งของขนาดเซลล์ ผลการวิเคราะห์ปริมาณน้ำมันสะสมภายในเซลล์ยีสต์เหล่านี้โดยเลี้ยงในอาหารผลิตน้ำมันที่ทราบองค์ประกอบทางเคมี ซึ่งมีกลูโคส 50 กรัม/ลิตร เป็นแหล่งคาร์บอน และบ่มที่อุณหภูมิ 30 องศาเซลเซียส เขย่า 200 รอบต่อนาที เป็นเวลา 6 วัน พบว่า Papiliotrema laurentii N-16.2, Rhodotorula (Rh.) sphaerocarpa 11-14.4, Saitozyma (Sait.) podzolica 11-11.3.1 และ Sait. podzolica N-8.4 เป็นยีสต์อุดมน้ำมัน การศึกษาการผลิตน้ำมันจากไฮโดรไลเสตใบอ้อย (sugarcane leaves hydrolysate, SLH) ของยีสต์อุดมน้ำมันที่คัดกรองได้ พบว่าทุกสายพันธุ์สามารถผลิตน้ำมันในไฮโดรไลเสตใบอ้อย โดย Rh. sphaerocarpa 11-14.4 ให้ผลผลิตน้ำมันสูงที่สุด (0.98 กรัม/ลิตร) การหาภาวะเหมาะที่สุดต่อการผลิตน้ำมันของ Rh. sphaerocarpa 11-14.4 ในไฮโดรไลเสตใบอ้อย พบว่าเมื่อใช้กล้าเชื้อที่เลี้ยงใน SLH ที่ผ่านการปรับด่างเกิน (overliming) (6% -DSLH) ที่เติมสารสกัดจากเซลล์ยีสต์ 3 กรัม/ลิตร และเพปโทน 3 กรัม/ลิตร และผลิตน้ำมันใน 12%-SLH (อัตราส่วนคาร์บอน/ไนโตรเจน เท่ากับ 24) ที่เติมโพแทสเซียมไดไฮโดรเจนฟอสเฟต (KH2PO4) 5 กรัม/ลิตร พีเอช 4.5 บ่มที่อุณหภูมิ 30 องศาเซลเซียส เขย่า 200 รอบต่อนาที เป็นเวลา 4 วัน ที่ภาวะดังกล่าวนี้ Rh. sphaerocarpa 11-14.4 …