Microbiology Commons^™

Iron Deficiency Increases Growth And Nitrogen-Fixation Rates Of Phosphorus-Deficient Marine Cyanobacteria, Nathan S. Garcia, Feixue Fu, Peter N. Sedwick, David A. Hutchins

OES Faculty Publications

Marine dinitrogen (N²)-fixing cyanobacteria have large impacts on global biogeochemistry as they fix carbon dioxide (CO₂) and fertilize oligotrophic ocean waters with new nitrogen. Iron (Fe) and phosphorus (P) are the two most important limiting nutrients for marine biological N₂ fixation, and their availabilities vary between major ocean basins and regions. A long-standing question concerns the ability of two globally dominant N₂-fixing cyanobacteria, unicellular Crocosphaera and filamentous Trichodesmium, to maintain relatively high N₂-fixation rates in these regimes where both Fe and P are typically scarce. We show that under P-deficient …

Elucidation Of A Novel Pathway In Staphylococcus Aureus: The Essential Site-Specific Processing Of Ribosomal Protein L27, Erin A. Wall

Theses and Dissertations

Ribosomal protein L27 is a component of the eubacterial large ribosomal subunit that has been shown to play a critical role in substrate stabilization during protein synthesis. This function is mediated by the L27 N-terminus, which protrudes into the peptidyl transferase center where it interacts with both A-site and P-site tRNAs as well as with 23S rRNA. We observed that L27 in S. aureus and other Firmicutes is encoded with a short N-terminal extension that is not present in most Gram-negative organisms, and is absent from mature ribosomes. The extension contains a conserved cleavage motif; nine N-terminal amino acids are …

Mysteries Of The Trypanosomatid Maxicircles: Characterization Of The Maxicircle Genomes And The Evolution Of Rna Editing In The Order Kinetoplastida, Preethi Ranganathan Iyengar

Theses and Dissertations

The trypanosomatid protists belonging to Order Kinetoplastida are some of the most successful parasites ever known to mankind. Their extreme physiological diversity and adaptability to different environmental conditions and host systems make them some of the most widespread parasites, causing deadly diseases in humans and other vertebrates.

This project focuses on their unique mitochondrion, called the kinetoplast, and more specifically involves the characterization of a part of their mitochondrial DNA (also called kinetoplast DNA or kDNA), the maxicircles, which are functional homologs of eukaryotic mitochondrial DNA in the kinetoplastid protists. We have sequenced and characterized the maxicircle genomes of 20 …

Role Of Extracytoplasmic Rna Polymerase Sigma 70 Factor, Pg0214, In The Survival Of Porphyromonas Gingivalis And In Adaptation To Environmental Stress., David M. Smith

Theses and Dissertations

Porphyromonas gingivalis, a gram-negative anaerobic, pathogenic bacterium is a major etiological agent in the initiation and progression of periodontal disease. Due to the ever-changing environment of the oral cavity, inhabitants like Porphyromonas gingivalis must possess the ability to adapt to changes in environmental conditions like pH, temperature, oxygen tension, and metal concentration. P. gingivalis should therefore have an efficient regulatory system in order to adapt and survive in the oral cavity. This response adaptation occurs at the transcriptional level, which involves alternative sigma factors. Extracytoplasmic function sigma (ECF-s) factors are the largest group of alternative sigma factors that play …

Characterization Of The Interactions Between Staphylococcal Phage 80 Alpha Scaffold And Capsid Proteins, Laura Klenow

Theses and Dissertations

Staphylococcal phage 80α can serve as a helper bacteriophage for a family of mobile genetic elements called Staphylococcus aureus pathogenicity islands (SaPIs). The prototype island, SaPI1, is able to hijack the 80α capsid assembly process and redirect capsid formation to yield smaller, phage-like transducing particles carrying SaPI DNA. Capsid size redirection is accomplished through two SaPI1-encoded gene products, CpmA and an alternate scaffold protein, CpmB. The normal 80α scaffold and the SaPI1 CpmB scaffold share a small block of conserved residues at their C-termini, several of which had been shown to be essential for CpmB function. This led to the …

Characterization Of A Novel Protease In Staphylococcus Aureus, Adam L. Johnson

Theses and Dissertations

A newly discovered cysteine protease, Prp, has been shown to perform an essential, site-specific cleavage of ribosomal protein L27 in Staphylococcus aureus. In Firmicutes and related bacteria, ribosomal protein L27 is encoded with a conserved N-terminal extension that must be removed to expose residues critical for ribosome function. Uncleavable and pre-cleaved variants were unable to complement an L27 deletion in S. aureus, indicating that this N-terminal processing event is essential and likely plays an important regulatory role. The gene encoding the responsible protease (prp) has been shown to be essential, and is found in all organisms …

Self-Cleaning Applications Of Tio2 By Photo-Induced Hydrophilicity And Photocatalysis, Swagata Banerjee, Dionysios Dionysiou, Suresh Pillai

Articles

Self-cleaning materials have gained considerable attention for both their unique properties and practical applications in energy and environmental areas. Recent examples of many TiO2-derived materials have been illustrated to understand the fundamental principles of self-cleaning hydrophilic and hydrophobic surfaces. Various models including those proposed by Wenzel, Cassie-Baxter and Miwa-Hashimoto are discussed to explain the mechanism of self-cleaning. Examples of semiconductor surfaces exhibiting the simultaneous occurrence of superhydrophilic and superhydrophobic domains on the same surface are illustrated, which can have various advanced applications in microfluidics, printing, photovoltaic, biomedical devices, anti-bacterial surfaces and water purification.

Several strategies to improve the efficiency of …

The Effects Of Motility And Chemotaxis On Vibrio Cholerae Colonization In Zebrafish, Paula Dietz

Wayne State University Theses

Vibrio cholerae, the cause of the diarrheal disease cholera, is a gram-negative, curved rod-shaped bacterium, with a single polar flagellum. V. cholerae is naturally found in aquatic environments and is highly motile. When it enters a human host, V. cholerae uses flagellar motility to pass through the stomach and into the small intestine. Once in the small intestine, motility genes are downregulated and virulence gene expression is upregulated. V. cholerae motility and chemotaxis effects have not yet been studied in a zebrafish model, a natural host of this bacterium. We hypothesize that V. cholerae in frame deletions of vital motility …

Francisella Tularensis Catalase Restricts Immune Function By Impairing Trpm2 Channel Activity, Nicole Lynn Flaherty

Legacy Theses & Dissertations (2009 - 2024)

As an innate defense mechanism, macrophages produce reactive species that weaken pathogens and serve as secondary messengers to modify signaling responses involved in immune function. The gram-negative bacterium F. tularensis utilizes its antioxidant armature to limit the host immune response but the mechanism behind this suppression has not been defined. Here we establish that F. tularensis limits Ca2+ entry thereby limiting actin reorganization and IL-6 production in a redox-dependent fashion. Wild-type (LVS) or catalase deficient F. tularensis (∆katG) show distinct profiles in their H2O2 scavenging capacity, 1 pM/sec and 0.015 pM/sec, respectively. Murine alveolar macrophages infected with ∆katG display distinct …

Analysis Of Strategies For Successful Identification, Reporting, And Prevention Of Carbapenem-Resistant Enterobacteriaceae (Cre) In Acute Health Care Facilities In New York State, Christen Leigh Mayer

Legacy Theses & Dissertations (2009 - 2024)

Background

Whole-Genome Sequencing Of Kaposi’S Sarcoma-Associated Herpesvirus From Zambian Kaposi’S Sarcoma Biopsy Specimens Reveals Unique Viral Diversity, Landon Olp, Adrien Jeanniard, Clemence Marimo, Charles Wood

Nebraska Center for Virology: Faculty Publications

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiological agent for Kaposi’s sarcoma (KS). Both KSHV and KS are endemic in sub-Saharan Africa where approximately 84% of global KS cases occur. Nevertheless, whole-genome sequencing of KSHV has only been completed using isolates from Western countries—where KS is not endemic. The lack of whole-genome KSHV sequence data from the most clinically important geographical region, sub-Saharan Africa, represents an important gap since it remains unclear whether genomic diversity has a role on KSHV pathogenesis. We hypothesized that distinct KSHV genotypes might be present in sub-Saharan Africa compared to Western countries. Using a KSHV-targeted enrichment …

Observed And Expected Incidence Of Cervical Cancer In Lusaka And The Southern And Western Provinces Of Zambia, 2007 - 2012, Mulele Kalima, Kennedy Lishimpi, Jane L. Meza, Shinobu Watanabe-Galloway, Susan C. Msadabwe, Catherine K. Mwaba, Aaron L. Shibemba, Lewis Banda, Charles Wood, Robert M. Chamberlain, Amr S. Soliman

Nebraska Center for Virology: Faculty Publications

Objectives—Cervical cancer is increasing but underestimated in developing countries. We calculated the observed and expected incidence of cervical cancer in Lusaka and Southern and Western provinces of Zambia.

Methods/Materials—Data for 2007-2012 was obtained for the 3 provinces. Data included age, residence, year of diagnosis, marital status, occupation, HIV, stage, radiotherapy and chemotherapy. Expected incidence in Southern and Western provinces was calculated based on observed incidence for Lusaka province, adjusting for HIV.

Results—Crude and age-standardized incidence rates (ASR) in Lusaka were 2-4 times higher than incidence in the other 2 provinces. Lusaka had a rate of 54.1/10⁵ and ASR of …

Crf07_Bc Strain Dominates The Hiv-1 Epidemic In Injection Drug Users In Liangshan Prefecture Of Sichuan, China, Lin Li, Daying Wei, Wan-Ling Hsu, Tianyi Li, Tao Gui, Charles Wood, Yongjian Liu, Hanping Li, Zuoyi Bao, Siyang Liu, Xiaolin Wang, Jingyun Li

Nebraska Center for Virology: Faculty Publications

The Liangshan prefecture in Sichuan province is an area in China severely affected by the HIV epidemic, with intravenous drug use (IDU) as the main risk factor. No reports on HIV subtypes prevalent in IDUs in Liangshan prefecture could be found. In this study, we have characterized the genotypes of HIV-1 in the IDU population in Liangshan prefecture and further determined the phylogenetic relationship of the CRF07_BC strains to HIV-1 sequences from the other regions of China, including Xinjiang and Yunnan provinces, to explore the pattern and possible diffusion pathway of HIV-1 in these regions. HIV-1-seropositive drug-naive IDUs identified in …

Hiv Integrase Mechanisms Of Resistance To Raltegravir, Elvitegravir, And Dolutegravir, Kyla Nicole Ross

Wayne State University Theses

ABSTRACT

HIV INTEGRASE MECHANISMS OF RESISTANCE TO RALTEGRAVIR, ELVITEGRAVIR, AND DOLUTEGRAVIR

by

KYLA ROSS

December 2015

Advisor: Dr. Ladislau Kovari

Major: Biochemistry and Molecular Biology

Degree: Master of Science

HIV-1 integrase (HIV-1 IN or IN) is a multimeric enzyme that integrates the HIV-1 genome into the chromosomes of infected CD4+ T-cells. Currently there are three FDA approved HIV-1 IN strand transfer inhibitors (INSTIs) used in clinical practice: raltegravir (RAL), elvitegravir (ELV), and dolutegravir (DTG). The [Q148H], [Q148H, G140S], [Q148R], [Q148R, G140A] and [N155H, E92Q] mutations decrease IN susceptibility to RAL and ELV and may result in therapeutic failure. As an …

Antimicrobial-Resistant Listeria Species From Retail Meat In Metro Detroit, Liziane Da Rocha

Wayne State University Theses

A total of 138 Listeria isolates, including 58 Listeria welshimeri, 44 Listeria monocytogenes, and 36 Listeria innocua, from retail meat were characterized by antimicrobial susceptibility tests against nine antimicrobials. In addition, the 44 L. monocytogenes were analyzed by serotype identification using PCR and genotyping using pulsed-filed gel electrophoresis (PFGE). Resistance to one or two antimicrobials was observed in 32 Listeria (23.2%). No multidrug resistance was identified. Tetracycline resistance was the most common resistance phenotype and identified in 22 Listeria isolates. Low prevalence of resistance to ciprofloxacin, erythromycin, gentamicin, and vancomycin was also detected. L. innocua demonstrated the highest overall prevalence …

ประสิทธิภาพของกลุ่มแบคทีเรียจากดินตะกอนบริเวณอ่าวไทยในการย่อยสลายเชิงชีวภาพของพอลิไซคลิกแอโรแมติกไฮโดรคาร์บอนแบบผสม, พลอยชนก จันทร์เอี่ยม

Chulalongkorn University Theses and Dissertations (Chula ETD)

อ่าวไทยเป็นจัดเป็นแหล่งทรัพยากรที่มีความอุดมสมบูรณ์และมีความสำคัญในด้านการคมนาคมทางน้ำ การขุดเจาะน้ำมัน การทำประมง รวมไปถึงเป็นแหล่งท่องเที่ยวที่สำคัญ ทำให้มีโอกาสเกิดการปนเปื้อนและการตกค้างของ PAHs ในดินตะกอน งานวิจัยนี้จึงมีเป้าหมายเพื่อทดสอบประสิทธิภาพกลุ่มแบคทีเรียที่คัดแยกจากตัวอย่างดินตะกอนอ่าวไทยในการย่อยสลาย PAHs ผสม โดยเริ่มจากตรวจนับจำนวนแบคทีเรียโดยวิธี MPN พบจำนวนแบคทีเรียทั้งหมดและแบคทีเรียย่อยสลาย PAHs ใน 22 ตัวอย่าง พบว่ามีค่าอยู่ในช่วง 1.77x108 - 8.30x109 และ 3.00 x104 ถึง 1.10x107 MPN/กรัมดินเปียก ตามลำดับ เมื่อรวมตัวอย่างดินตะกอนตามลักษณะทางกายภาพของพื้นที่และดินตะกอน ได้เป็น 7 ตัวอย่าง (G1-G7) และเพิ่มจำนวนแบคทีเรียย่อยสลาย PAHs ผสมด้วยวิธีเอนริชเมนท์ พบว่ากลุ่มแบคทีเรีย G7 มีประสิทธิภาพในการย่อยสลาย PAHs ผสมได้สูงที่สุด โดยย่อยสลาย PAHs ผสม 4 ชนิด ได้แก่ ฟีแนนทรีน แอนทราซีน ฟลูออแรนทีน และไพรีน ความเข้มข้นชนิดละ 50 มิลลิกรัม/ลิตรได้ 82, 92, 62 และ 50% ตามลำดับ ใน 14 วัน นอกจากนี้ในการย่อยสลาย PAHs 5 ชนิด กลุ่มแบคทีเรีย G7 ยังสามารถย่อยสลายเบนโซ[เอ]ไพรีนซึ่งมีความเป็นพิษสูง ได้ถึง 38% จากความเข้มข้นเริ่มต้น 10 มิลลิกรัม/ลิตร ในขณะที่ยังคงรักษาประสิทธิภาพในการย่อยสลาย PAHs ผสม 4 ชนิดเดิมไว้ได้ อีกทั้งมีประสิทธิภาพในการย่อยสลาย PAHs ผสม 7 ชนิด ได้แก่ อะซีแนพธีน อะซีแนพธิลีน ฟลูออรีน ฟีแนนทรีน แอนทราซีน ฟลูออแรนทีน และไพรีน ซึ่งเพิ่ม PAHs ชนิดมวลโมเลกุลต่ำที่ความเข้มข้นสุดท้ายชนิดละ 30 มิลลิกรัม/ลิตรได้ นอกจากนี้ กลุ่มแบคทีเรีย …

Development Of Novel Fluorescent Tools For Investigating Virulence Factors And Drug Susceptibility In Mycobacterium Tuberculosis, Kaley Wilburn

HIM 1990-2015

Mycobacterium tuberculosis (Mtb) is the causative agent of Tuberculosis (TB), a life-threatening disease primarily affecting the lungs that infects about one third of the world's population and causes 1.3 million deaths annually. It is estimated that TB has been infecting humans for around 70,000 years and has killed more people than any other infectious disease. The highly effective, persistent, and multifaceted virulence strategies that have allowed Mtb to continue to spread and thrive for so long are still poorly understood at the molecular level. This lack of knowledge contributes to ongoing challenges to curing TB. Although drugs capable of killing …

Detection Of Drug-Resistance Conferring Snps In Mycobacterium Tuberculosis Using Binary Dnazymes, Marina Addario

HIM 1990-2015

Mycobacterium tuberculosis (Mtb) is the pathogen that causes Tuberculosis (TB) and is responsible for an average of 1.5 million deaths annually. Although a treatment regimen does exist, Multi-Drug Resistant (MDR-TB) and eXtremely Drug Resistant (XDR-TB) TB strains are becoming a more prevalent concern partly due to failure of patient compliance with the current six to nine month drug treatment regimen. The current diagnostic methods are not able to identify these MDR and XDR-TB strains efficiently therefore more effective point-of-care (POC) diagnostics and drug susceptibility testing (DST) are urgently needed to detect drug resistance and facilitate prompt, appropriate treatment plans. In …

Elucidating The Molecular Pathway Of Atypical Plasmodium Falciparum Kinases Through Substrate Characterization, Daniel Segarra

HIM 1990-2015

Plasmodium falciparum, the organism responsible for the most prevalent and most virulent cases of malaria in humans, poses a major burden to the developing world. The parasite is increasingly developing resistance to traditional therapies, such as chloroquine, so the need to determine novel drug targets is more prevalent than ever. One such method involves targeting proteins unique to the malarial proteome that do not have homologues in humans. An especially promising group of targets are protein kinases, which are involved in many different biochemical pathways within the cell. Eukaryotic cell cycle progression is moderated by a family of protein kinases …

Developing Microbial Biomarkers To Non-Invasively Assess Health In Wild Elk (Cervus Canadensis) Populations, Samuel B. Pannoni

Undergraduate Theses, Professional Papers, and Capstone Artifacts

The composition of the intestinal bacterial community (intestinal microbiome) of mammals is associated with changes in diet, stress, disease and physical condition of the animal. The relationship between health and the microbiome has been extensively demonstrated in studies of humans and mice; this provides strong support for its potential utility in wildlife. When managing elk (Cervus canadensis), federal and state agencies currently must rely on invasive sampling and coarse demographic data on which to base their decisions. By developing microbiome-based biomarkers that vary as a function of elk body condition and disease (i.e. microbial biomarkers), we hope to …