Microbiology Commons^™

Evaluation Of Intra-Species Diversity Of Oxalobacter Formigenes Strains Using Pulsed-Field Gel Electrophoresis (Pfge) And Multiplex Pcr, Nivedita Pareek

Masters Theses

Oxalobacter formigenes is a beneficial, strict anaerobic gut bacterium that plays an important role in the prevention of kidney stone disease with a unique characteristic of using only oxalate as a carbon and energy source. To date, twenty-one strains of O. formigenes have been isolated which are further divided into two groups based on differences in the patterns of cell membrane lipids, cellular proteins, and nucleic acid fragments. The objective of the study was to evaluate intra-species diversity of O. formigenes strains using pulsed-field gel electrophoresis (PFGE) and multiplex PCR.

Nine pure cultures of O. formigenes strains (5 strains group …

Xylan Metabolism By Caulobacter Crescentus, Viet Bui

Masters Theses

Bacteria present unique opportunities to explore the molecular mechanisms of nutrient acquisition processes at single cell level under various experimental conditions. Caulobacter crescentus is a gram-negative oligotrophic environmental bacterium with adaptive physiological responses, such as slow growth or complete arrest of cell cycle, presence of sessile and motile progenies with the sessile cells growing stalk to enhance nutrient uptake for growth in low-nutrient conditions. Details of plant polysaccharide-derived carbon compound, such as cellobiose, maltose, and xylose utilization by C. crescentus can be found but molecular details or mechanisms of polysaccharide utilization, such as xylan, has not been reported. Database analyses …

Serosurvey For Evidence Of Dengue And West Nile Virus Human Infections In El Paso, Texas, Veronica Suarez

Open Access Theses & Dissertations

Dengue viruses (DENV), including the 4 serotypes are the cause of dengue fever and dengue hemorrhagic fever. The viruses are transmitted by Aedes aegypti mosquitoes in urban communities in tropical, sub-tropical, and temperate regions and are the cause of the highest rate of infection and death of all known Flaviviruses. DENV are endemic in United States (US) -Mexico (MX) border communities in the Rio Grande Valley and suspected of being endemic in Ciudad Juarez, a sister city to El Paso, TX. To determine if DENV were endemic in the El Paso community, cord-blood samples from mothers were tested for antibody …

Membrane Microdomains As Platforms For Extra-Cellular Fusions, Michael Hantak

Dissertations

Life requires biological membranes. Membrane-enclosed compartments separate and unite through dynamic fission and fusion reactions. These are catalyzed processes that are central in organismal biogenesis. This dissertation focuses on extracellular membrane fusions, which are central to several processes. (1) Enveloped viruses enter cells through membrane fusions. (2) Extracellular vesicles (EVs) also deliver molecules into cells through membrane fusions. (3) Entire cells also fuse together, generating fertilized zygotes, skeletal muscles, and giant cell macrophages.Mechanisms of extracellular membrane fusion are poorly understood. This dissertation aimed to further define these mechanisms. We focused on regulatory cofactors, including tetraspanins, transmembrane proteins that cluster into …

Functional Analysis Of Bacillus Anthracis Aspartate Transcarbamoylase And Dihydroorotase, Katelyn Leigh Schwager Silva

Wayne State University Theses

There are many enzymes required for efficient and proper pyrimidine biosynthesis. The two that are most important and were discussed in this thesis are aspartate transcarbamoylase (ATCase) and dihydroorotase (DHOase). Both play an important role in not only pyrimidine biosynthesis production, but also mechanistic regulation of de novo synthesis. Anthrax is an infection caused by Bacillus anthracis. Here we studied ATCase and DHOase in Bacillus Anthracis. In this thesis we understood the effects of the enzymes ATCase and DHOase on pyrimidine biosynthesis. Adequate inhibitors of these enzymes would result in cell death and could pose as a cure to infection …

A Comparative Study Of Equine Gut Microbiomes Using 16s And 18s Rrna Sequencing, Jillian Jorgenson

Undergraduate Honors Thesis Projects

The gut microbiome of domestic horses (Equus ferus caballus) can be broken down into two primary divisions of interest: (1) prokaryotic composition, consisting of bacteria and archaea and (2) fungal composition. Within the gut, there are also eukaryotic parasite communities that may interact with the microbiome. While each has been the subject of various scientific explorations, in this study we analyze the potential interconnectedness of these categories. To determine the extent to which each component of the gut microbiome/parasitic communities influences the other, DNA was extracted and amplified from the fecal samples of eight horses. A combination of …

Illumination Of The Golgi Apparatus Of Pathogenic And Nonpathogenic Naegleria Species, Tyler M. Poe

Theses and Dissertations

In this study, Naegleria fowleri, a pathogenic amoeba and the causative agent of Primary Amebic Meningoencephalitis (PAM), was utilized to determine the presence or absence of classically conserved Golgi molecules featured in the expression of a Golgi apparatus. Previous studies concluded no Golgi expression via light microscopy and transmission electron microscopy, but a recent report on Naegleria gruberi indicated the presence of dispersed Golgi tubules. Non-pathogenic species of the Naegleria genus such as Naegleria gruberi 30540 and Naegleria lovaniensis 30569 were utilized in Western immunoblot analysis compared to reduced whole-cell lysate proteins of two strains of N. fowleri and …

Adaptation Of The Streptococcal Collagen-Like Protein 1, Scl1, Of Group A Streptococcus To Recognize Fibronectin Type Iii Repeats, Dudley H. Mcnitt

Graduate Theses, Dissertations, and Problem Reports (ETD)

Background: Group A Streptococcus (GAS) is responsible more than 700 million infections worldwide each year. Most of these infections start with initial colonization of the throat and skin, which is augmented by surface adhesins. The streptococcal collagen-like protein 1 (Scl1) is a major adhesin expressed by GAS that contains an N-terminal sequence-variable (V) domain, protruded away from the cell surface by the collagen domain. The Scl-V domain is comprised of three pairs of anti-parallel α-helices interconnected by surface-exposed loops. For attachment, GAS adhesins require a portal of entry, such as a wound or breach in the epithelium, to enter …

Genome Sequences Of Three Cruciviruses Found In The Willamette Valley (Oregon), Ignacio De La Higuera, Ellis L. Torrance, Alyssa A. Pratt, George Kasun, Amberlee Maluenda, Kenneth M. Stedman

Biology Faculty Publications and Presentations

Cruciviruses are single-stranded DNA (ssDNA) viruses whose genomes suggest the possibility of gene transfer between DNA and RNA viruses. Many crucivirus genome sequences have been found in metagenomic data sets, although no crucivirus has been isolated. Here, we present the complete genome sequences of three cruciviruses recovered from environmental samples from Oregon.

Crystallographic Studies On Host-Interacting Proteins Of Phage K Virion, Antonio Pichel Beleiro

Theses

Phage K is a lytic bacteriophage that infects a broad range of staphylococci, including some methicillin-resistant Staphylococcus aureus strains. Phage K attaches to its host via a baseplate. The contracted conformation of the baseplate contains a fiber and two receptorbinding proteins responsible for the interaction with the host. The native conformation of the baseplate also includes a tail central spike that shears off after contraction. The aim of the thesis is the structural characterization of phage K receptor-binding proteins and tail central spike. Experimentally, the thesis relies on crystallographic methods, which encompass: production of suitable sample, crystallization, diffraction, and data …

Crystallographic Structure Determination Of Bacteriophage-Encoded Enzymes That Specifically Target Pathogenic Bacteria, Marta Sanz Gaitero

Theses

Antibiotic resistance is becoming a serious public health concern. Infections that some decades ago could be treated with antibiotics now sometimes do not respond to traditional treatment, causing higher mortality and economic losses. An alternative to the use of antibiotics are bacteria's natural predators, bacteriophages (or phages), and specifically their lytic enzymes. These proteins are produced by phages to degrade bacterial peptidoglycan to inject their genetic material into the bacteria (virion-associated peptidoglycan hydrolases) or to release their progeny once the infection is finished (endolysins). They can be applied exogenously to lyse Gram-positive bacteria or be genetically engineered to lyse Gram-negative …

Impact Of Seasonal And Host-Related Factors On The Intestinal Microbiome And Cestode Community Of Sorex Cinereus And Sorex Monticola, Katelyn D. Cranmer

College of Graduate Studies: Theses & Dissertations

The intestinal microbiome of mammals plays a significant role in host health and response to environmental stimuli and can include both beneficial native bacteria as well as parasitic worms. In this study, I examined the intestinal cestode and bacterial communities of two closely related species of shrew, Sorex monticola and Sorex cinereus, over a six month period in 2016. Specimens were collected approximately every three weeks from May to October from the Sangre de Cristo Mountains in Cowles, New Mexico. A total of 79 shrews were prepared with the gastrointestinal tracts removed and flash-frozen in liquid nitrogen. An additional …

A Poxvirus Pseudokinase Represses Viral Dna Replication Via A Pathway Antagonized By Its Paralog Kinase, Annabel T. Olson, Zhigang Wang, Amber B. Rico, Matthew S. Wiebe

Nebraska Center for Virology: Faculty Publications

Poxviruses employ sophisticated, but incompletely understood, signaling pathways that engage cellular defense mechanisms and simultaneously ensure viral factors are modulated properly. For example, the vaccinia B1 protein kinase plays a vital role in inactivating the cellular antiviral factor BAF, and likely orchestrates other pathways as well. In this study, we utilized experimental evolution of a B1 deletion virus to perform an unbiased search for suppressor mutations and identify novel pathways involving B1. After several passages of the ΔB1 virus we observed a robust increase in viral titer of the adapted virus. Interestingly, our characterization of the adapted viruses reveals that …

Near-Atomic Structure Of A Giant Virus, Qianglin Fang, Dongjie Zhu, Irina Agarkova, Jagat Adhikari, Thomas Klose, Yue Liu, Zhenguo Chen, Yingyuan Sun, Michael L. Gross, James L. Van Etten, Xinzheng Zhang, Michael G. Rossmann

Nebraska Center for Virology: Faculty Publications

Although the nucleocytoplasmic large DNA viruses (NCLDVs) are one of the largest group of viruses that infect many eukaryotic hosts, the near-atomic resolution structures of these viruses have remained unknown. Here we describe a 3.5 Å resolution icosahedrally averaged capsid structure of Paramecium bursaria chlorella virus 1 (PBCV-1). This structure consists of 5040 copies of the major capsid protein, 60 copies of the penton protein and 1800 minor capsid proteins of which there are 13 different types. The minor capsid proteins form a hexagonal network below the outer capsid shell, stabilizing the capsid by binding neighboring capsomers together. The size …

Relationship Between The Cervical Microbiome, Hiv Status, And Precancerous Lesions, Cameron Klein, Daniela Gonzalez, Kandali Samwel, Crispin Kahesa, Julius Mwaiselage, Nirosh Aluthge, Samodha Fernando, John T. West, Charles Wood, Peter C. Angeletti

Nebraska Center for Virology: Faculty Publications

Nearly all cervical cancers are causally associated with human papillomavirus (HPV). The burden of HPV-associated dysplasias in sub-Saharan Africa is influenced by HIV. To investigate the role of the bacterial microbiome in cervical dysplasia, cytobrush samples were collected directly from cervical lesions of 144 Tanzanian women. The V4 hypervariable region of the 16S rRNA gene was amplified and deep sequenced. Alpha diversity metrics (Chao1, PD whole tree, and operational taxonomic unit [OTU] estimates) displayed significantly higher bacterial richness in HIV-positive patients (P = 0.01) than in HIV-negative patients. In HIV-positive patients, there was higher bacterial richness in patients with …

Persistent Viral Reservoirs In Lymphoid Tissues In Siv-Infected Rhesus Macaques Of Chinese-Origin On Suppressive Antiretroviral Therapy, Summer Siddiqui, Stefanie Perez, Yong Gao, Lara Doyle-Meyers, Brian T. Foley, Qingsheng Li, Binhua Ling

Nebraska Center for Virology: Faculty Publications

Understanding HIV latent reservoirs in tissues is essential for the development of new strategies targeting these sites for eradication. Here, we assessed the size of latent reservoirs and the source of residual viruses in multiple lymphoid tissues of SIV-infected and fully suppressed rhesus macaques of Chinese-origin (cRMs). Eight cRMs were infected with SIVmac251 and treated with tenofovir and emtricitabine daily for 24 weeks initiated 4 weeks post-infection. Four of the eight animals reached sustained full viral suppression with undetectable viremia. The levels of cell-associated SIV DNA varied in peripheral blood mononuclear cells (PBMCs) and multiple lymphoid tissues, but with higher …

A Single-Cycle Adenovirus Type 7 Vaccine For Prevention Of Acute Respiratory Disease, Brianna L. Bullard, Brigette N. Corder, Eric A. Weaver

Nebraska Center for Virology: Faculty Publications

Adenovirus type 7 (Ad7) infection is associated with acute respiratory disease (ARD), especially in military recruits living in close quarters. Recently, several outbreaks of Ad7 infections have occurred in civilian populations, with some cases leading to death. However, the current Ad7 vaccine is licensed for use only in military recruits because it utilizes an orally delivered wild type virus which is shed in the stool for 28 days after immunization. This poses a safety risk due to the possibility of virus spread to vulnerable populations. To address the need for a safer Ad7 vaccine for use in civilian populations, we …

A Double Humanized Blt-Mice Model Featuring A Stable Human-Like Gut Microbiome And Human Immune System, Lance Daharsh, Jianshui Zhang, Amanda E. Ramer-Tait, Qingsheng Li

Nebraska Center for Virology: Faculty Publications

Humanized mice (hu-mice) that feature a functional human immune system have fundamentally changed the study of human pathogens and disease. They can be used to model diseases that are otherwise difficult or impossible to study in humans or other animal models. The gut microbiome can have a profound impact on human health and disease. However, the murine gut microbiome is very different than the one found in humans. There is a need for improved pre-clinical hu-mice models that have an engrafted human gut microbiome. Therefore, we created double hu-mice that feature both a human immune system and stable human-like gut …

The Vaccinia Virus (Vacv) B1 And Cellular Vrk2 Kinases Promote Vacv Replication Factory Formation Through Phosphorylation-Dependent Inhibition Of Vacv B12, Annabel T. Olson, Zhigang Wang, Annabel Olson, Alexandria C. Linville, Brianna L. Bullard, Eric A. Weaver, Clinton Jones, Matthew S. Wiebe

Nebraska Center for Virology: Faculty Publications

Comparative examination of viral and host protein homologs reveals novel mechanisms governing downstream signaling effectors of both cellular and vi- ral origin. The vaccinia virus B1 protein kinase is involved in promoting multiple facets of the virus life cycle and is a homolog of three conserved cellular enzymes called vaccinia virus-related kinases (VRKs). Recent evidence indicates that B1 and VRK2 mediate a com- mon pathway that is largely uncharacterized but appears independent of previous VRK substrates. Interestingly, separate studies described a novel role for B1 in inhibiting vac- cinia virus protein B12, which otherwise impedes an early event in the …

Histone Acetylation Increases In Response To Ferulic, Gallic, And Sinapic Acids Acting Synergistically In Vitro To Inhibit Candida Albicans Yeast‐To‐Hyphae Transition, Cristiane R. S. Câmara, Qin-Yin Shi, Matthew Pedersen, Richard Zbasnik, Kenneth Nickerson, Vicki Schlegel

Department of Food Science and Technology: Faculty Publications

Novel treatments are needed to prevent candidiasis/candidemia infection due to the emergence of Candida species resistant to current antifungals. Considering the yeast-to‐hyphae switch is a critical factor to Candida albicans virulence, phenols common in plant sources have been reported to demonstrating their ability to prevent dimorphism. Therefore, phenols present in many agricultural waste stress (ferulic (FA) and gallic (GA) acid) were initially screened in isolation for their yeast‐to‐hyphae inhibitory properties at times 3, 6, and 24 hr. Both FA and GA inhibited 50% of hyphae formation inhibitory concentration (IC₅₀) but at a concentration of 8.0 ± 0.09 and …

Improved Methods For The Quantification Of Viable Ascaris Suum And Application To Biosolids, Tanner Keyzers

Dissertations, Master's Theses and Master's Reports

The current method for detection of Ascaris ova in biosolids and wastewater has several drawbacks including being labor and time intensive as well as being difficult to quantify viable ova that have larvated during treatment. The goal of this thesis was to improve several methods for the detection and quantification of Ascaris ova during long term-storage of biosolids including improvement of quantifying viable ova using a heat and bleach treatment to promote movement of larvae inside of ova, and comparison of the traditional microscopic method with qPCR and PMA-qPCR to prevent the false-positive results. Improved methods to promote movement of …

Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp

Dissertations, Master's Theses and Master's Reports

Boreal peatlands store approximately one third of the earth’s terrestrial carbon, locked away in currently waterlogged and frozen conditions. Peatlands of boreal and arctic ecosystems are affected increasingly by shifting hydrology caused by climate change. The consequences of these relatively rapid ecosystem changes on carbon cycling between the landscape and the atmosphere could provide an amplifying feedback to climate warming. Alternatively, the advancement of terrestrial vegetation into once waterlogged soils could uptake carbon as a sink. Previous work suggests that fens will become an increasingly dominant landscape feature in the boreal. However, studies investigating fens, their response to hydrologic and …

การต้านการเจริญและการผลิตสารพิษจากราของ Aspergillus Flavus และ Aspergillus Carbonarius โดยยีสต์ปฏิปักษ์, พิชามญชุ์ โสมา

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อศึกษากลไกสำคัญในการยับยั้งการเจริญและการผลิตอะฟลาทอกซินบี 1 และโอคราทอกซินเอของ Aspergillus flavus และ Aspergillus carbonarius ตามลำดับ โดยใช้ยีสต์ปฏิปักษ์สามชนิด ได้แก่ Wickerhamomyces anomalus MSCU 0652, Saccharomyces cerevisiae MSCU 0654 และ Kluyveromyces marxianus MSCU 0655 จากผลการวิจัยพบว่า ยีสต์ปฏิปักษ์ทั้งสามชนิดสามารถยับยั้งการเจริญและการผลิตสารพิษจากราได้อย่างมีประสิทธิภาพแตกต่างกัน โดยมีกลไกสำคัญ ได้แก่ การสร้างสารประกอบอินทรีย์ระเหยง่ายที่มีผลต่อลักษณะทางสัณฐานวิทยาของเส้นใยรา และเมื่อศึกษาปัจจัยที่ส่งผลต่อการสร้างสารประกอบอินทรีย์เหยง่ายของยีสต์ปฏิปักษ์พบว่า W. anomalus MSCU 0652 มีประสิทธิภาพในการสร้างสารประกอบอินทรีย์ระเหยง่ายเพื่อยับยั้งการเจริญและการผลิตอะฟลาทอกซินบี 1 ของ A. flavus M3T8R4G3 ได้ดีที่สุดเมื่อเจริญบนอาหารที่ค่าความเป็นกรด-เบสเท่ากับ 5 (81.27±1.23 เปอร์เซ็นต์) บ่มที่อุณหภูมิห้อง (81.38±1.80 เปอร์เซ็นต์) และค่าความเข้มข้นของอาหารเลี้ยงยีสต์ปกติ (82.86±1.14 เปอร์เซ็นต์) และลดการผลิตอะฟลาทอกซินบี 1 ได้ดีที่สุดเมื่อเจริญบนอาหารที่ค่าความเป็นกรด-เบสเท่ากับ 4.5 (99.91±0.01 เปอร์เซ็นต์) บ่มที่ 25 องศาเซลเซียส (99.73±0.21 เปอร์เซ็นต์) และค่าความเข้มข้นของอาหารเลี้ยงยีสต์ 0.5 เท่า (99.67±0.12 เปอร์เซ็นต์) สำหรับ A. carbonarius TK4.2 พบว่า W. anomalus MSCU 0652 มีประสิทธิภาพในการยับยั้งการเจริญและการผลิตสารพิษจากราได้ดีที่สุดเมื่อเลี้ยงบนอาหารที่ค่าความเป็นกรด-เบสเท่ากับ 5 (82.42±2.76 เปอร์เซ็นต์) บ่มที่อุณหภูมิห้อง (81.20±2.65 เปอร์เซ็นต์) และค่าความเข้มข้นของอาหารเลี้ยงยีสต์ปกติ (83.88±0.32 เปอร์เซ็นต์) และลดการผลิตโอคราทอกซินเอได้ดีที่สุดเมื่อเลี้ยงบนอาหารที่ค่าความเป็นกรด-เบสเท่ากับ 5 (99.91±0.07 เปอร์เซ็นต์) บ่มที่อุณหภูมิห้อง (99.92±0.01 เปอร์เซ็นต์) และค่าความเข้มข้นของอาหารเลี้ยงยีสต์ปกติ (99.97±0.01 เปอร์เซ็นต์) นอกจากนี้ เมื่อทดสอบความสามารถในการลดการปนเปื้อนสารพิษจากราพบว่า ตะกอนเซลล์ยีสต์ที่ไม่มีชีวิตของ S. cerevisiae …

การผลิตสารลดแรงตึงผิวชีวภาพจาก Bacillus Velezensis B49 และการยับยั้งราก่อโรคพืช, สิรภพ ภูมิภูติกุล

Chulalongkorn University Theses and Dissertations (Chula ETD)

ราก่อโรคพืชสามารถทำลายผลผลิตทางการเกษตรได้ทั่วโลก การใช้วิธีทางชีวภาพสามารถลดการใช้สารเคมีในการกำจัดราก่อโรคพืชได้ ราก่อโรคพืชที่พบส่วนใหญ่ ได้แก่ Acremonium furcatum, Colletotrichum gloeosporioides, Fusarium moniliforme, Fusarium proliferatum, Fusarium solani, Phytophthora palmivora และ Pyricularia oryzae การศึกษาก่อนหน้านี้พบว่า Bacillus velezensis B49 สามารถยับยั้งราที่ก่อโรคในพืช และสามารถสร้างสารลดแรงตึงผิวชีวภาพได้ งานวิจัยนี้มีวัตถุประสงค์เพื่อเพิ่มการผลิตสารลดแรงตึงผิวชีวภาพจาก B. velezensis B49 และทดสอบการยับยั้งราก่อโรคพืชด้วยสารลดแรงตึงผิวชีวภาพที่ผลิตได้ ผลการทดสอบการยับยั้งการเจริญของราก่อโรคพืชโดยใช้เทคนิคการขีดเชื้อและเทคนิคผสมน้ำเลี้ยงเชื้อของ B. velezensis B49 แสดงความสามารถในการยับยั้งการเจริญของราต่อโรคพืชทั้ง 7 ชนิด ทดสอบสมบัติการผลิตสารลดแรงตึงผิวชีวภาพของ B. velezensis B49 โดยใช้ 4 วิธีที่แตกต่างกัน ได้แก่ การทดสอบการยุบตัวของน้ำเลี้ยงเชื้อบนฟิล์มน้ำมัน, การทดสอบการแตกของเม็ดเลือดแดง, การทดสอบการกระจายตัวของน้ำมัน และการทดสอบการเกิดอิมัลชัน พบว่า B. velezensis B49 ให้ผลบวกกับทั้ง 4 วิธี ซึ่งยืนยันได้ว่า B. velezensis B49 สามารถผลิตสารลดแรงตึงผิวชีวภาพได้ การทดสอบผลของความเป็นกรดเบสที่มีต่อสมบัติของสารลดแรงตึงผิวชีวภาพ พบว่าที่ความเป็นกรดเบสระหว่าง pH 2 – 10 ทำให้เกิดอิมัลชันไม่แตกต่างกัน แต่เมื่อความเป็นกรดเบสสูงขึ้น ส่งผลทำให้การเกิดอิมัลชันลดลงจนกระทั่งไม่เกิดอิมัลชันเลย ส่วนการทดสอบผลของอุณหภูมิที่มีต่อสมบัติของสารลดแรงตึงผิวชีวภาพของ B. velezensis B49 พบว่า อุณหภูมิไม่มีผลต่อสมบัติการเกิดอิมัลชัน การทดสอบผลของแหล่งคาร์บอนและไนโตรเจนที่มีต่อการผลิตสารลดแรงตึงผิวชีวภาพในอาหาร Mineral salt solution พบว่า B. velezensis B49 สามารถเจริญได้ในแหล่งคาร์บอน ได้แก่ กลูโคส, ฟรุกโทส และซูโครส ส่วนแหล่งไนโตรเจน ได้แก่ แอมโมเนียมไนเตรต และแอมโมเนียมซัลเฟต อย่างไรก็ตาม อาหารสูตรสมบูรณ์ให้ผลการเกิดอิมัลชันสูงกว่า ความสัมพันธ์ระหว่างการเจริญและการเกิดอิมัลชันต่อเวลา พบว่า B. velezensis B49 …

Efficacy Of Cold Plasma For Direct Deposition Of Antibiotics As A Novel Approach For Localized Delivery And Retention Of Effect, Agatha Los, Dana Ziuzina, Daniela Boehm, Lu Han, Denis O'Sullivan, Liam O'Neill, Paula Bourke

Articles

Antimicrobial coating of medical devices has emerged as a potentially effective tool to prevent or ameliorate device-related infections. In this study the plasma deposition process for direct deposition of pharmaceutical drugs on to a range of surfaces and the retention of structure function relationship and antimicrobial efficacy against mono-species biofilms were investigated. Two selected sample antibiotics—ampicillin and gentamicin, were deposited onto two types of surfaces—polystyrene microtiter plates and stainless steel coupons. The antimicrobial efficacy of the antibiotic-coated surfaces was tested against challenge populations of both planktonic and sessile Escherichia coli and Pseudomonas aeruginosa, with responses monitored for up to …

The Abundance Of Akkermansia Muciniphila And Its Relationship With Sulphated Colonic Mucins In Health And Ulcerative Colitis, Helen Earley, Grainne Earley, Aine Balfe, J. Calvin Coffey, Desmond C. Winter, Ronan O'Connell

Articles

Akkermansia muciniphila utilises colonic mucin as its substrate. Abundance is reduced in ulcerative colitis (UC), as is the relative proportion of sulphated mucin in the mucus gel layer (MGL). It is unknown if these phenomena are related, however reduced sulphated mucins could contribute to reduced abundance, owing to a lack of substrate. The aim of this study was to quantify A. muciniphila within the MGL and to relate these findings with markers of inflammation and the relative proportion of sulphomucin present. Colonic biopsies and mucus brushings were obtained from 20 patients with active UC (AC), 14 with quiescent UC (QUC) …

Riparian Zone Soil Microbial Community Dynamics: Interactions With Nutrient Loadings, James Bannister

Theses and Dissertations (Comprehensive)

Riparian zones are a type of wetland described as the interface between land and a body of water such as a river or stream. Riparian zones are effective buffers against anthropogenic pollutants and nutrient loads from non-point sources that can greatly diminish water quality. Riparian zones can host a variety of plant species and associated microbial communities. The combined biological processes of plants, bacteria, and arbuscular mycorrhizal fungi (AMF) are key to nutrient cycling and nutrient removal in riparian zones. As such, understanding the factors that influence them is critical for watershed management. This research is targeted at obtaining a …

การตรึงยีสต์จากน้ำทะเลย่อยสลายดีเซลบนเปลือกหอยแครงและการประยุกต์, สุรสิทธิ์ พฤกษวานิช

Chulalongkorn University Theses and Dissertations (Chula ETD)

จุลินทรีย์สายพันธุ์ SP21 ที่คัดแยกได้จากน้ำทะเลปนเปื้อนน้ำมัน จากอำเภอดอนสัก จังหวัดสุราษฎร์ธานี ลักษณะทางสัณฐานวิทยาและการเปรียบเทียบลำดับนิวคลิโอไทด์ 26s rDNA พบว่าสายพันธุ์ SP21 มีความใกล้เคียงกับยีสต์ Candida viswanathii 100% C. viswanathii สายพันธุ์ SP21 สามารถย่อยสลาย 1% ดีเซล ในน้ำทะเลสังเคราะห์ (SSW) ได้ 96.18 ± 1.2% ใน 7 วัน ในขณะที่ชุดควบคุมที่ไม่เติมยีสต์ดีเซลลดลงเพียง 11.80 ± 6.13% เมื่อตรึง C. viswanathii สายพันธุ์ SP21 บนเปลือกหอยแครง พบว่าสามารถตรึงเซลล์ได้ 5.70 log CFU/กรัม เมื่อบ่มเซลล์ร่วมกับเปลือกหอย 1 ชั่วโมง และสามารถตรวจพบเซลล์ตรึงโดยกล้องจุลทรรศน์อิเล็กตรอนแบบส่องกราด เซลล์ตรึงสามารถย่อยสลาย 1% ดีเซล ในอาหารน้ำทะเลสังเคราะห์ (SSW) ได้ 98.70 ± 0.57% ในขณะที่ชุดทดลองเปลือกหอยแครงที่ไม่ตรึงเชื้อดีเซลลดลงเพียง 1.65 ± 7.34% การตรึงเซลล์ช่วยเพิ่มประสิทธิภาพการย่อยสลายดีเซลที่ความเข้มข้นสูง 3% และ 5% ได้ 94.06 ± 5.94% และ 86.50 ± 13.70% ในเวลา 7 วัน ตามลำดับ ในขณะที่เซลล์อิสระสามารถย่อยสลายได้เพียง 85.12 ± 1.67% และ 51.69 ± 1.79% เซลล์ตรึงยังสามารถย่อยสลาย 1% ดีเซล ในน้ำกร่อยสังเคราะห์ (SBW) และน้ำจืดสังเคราะห์ (CFMM) ได้ 93.21 ± 0.76% และ 90.25 ± 6.93% …

Cationic Biaryl 1,2,3-Triazolyl Peptidomimetic Amphiphiles: Synthesis, Antibacterial Evaluation And Preliminary Mechanism Of Action Studies, Andrew J. Tague, Papanin Putsathit, Katherine A. Hammer, Steven M. Wales, Daniel R. Knight, Thomas V. Riley, Paul A. Keller, Stephen G. Pyne

Research outputs 2014 to 2021

Synthetic small molecular antimicrobial peptidomimetics represent a promising new class of potential antibiotics due to their membrane-disrupting ability and their decreased propensity for bacterial resistance. A library of 43 mono- and di-cationic biaryl 1,2,3-triazolyl peptidomimetics was designed and synthesized based upon previously established lead biarylpeptidomimetics and a known pharmacophore. A reliable, facile and modular synthetic pathway allowed for the efficient synthesis of multiple unique scaffolds which were subjected to divergent derivatization to furnish the amphiphilic compounds. In vitro testing revealed enhanced antibacterial efficacy against a range of pathogenic bacteria, including bacterial isolates with methicillin, vancomycin, daptomycin, or multi-drug resistance. Preliminary …

Metaproteomics Reveal That Rapid Perturbations In Organic Matter Prioritize Functional Restructuring Over Taxonomy In Western Arctic Ocean Microbiomes, Molly P. Mikan, H. Rodger Harvey, Emma Timmins-Schiffman, Michael Riffle, Damon H. May, Ian Salter, William S. Noble, Brook L. Nunn

OES Faculty Publications

We examined metaproteome profiles from two Arctic microbiomes during 10-day shipboard incubations to directly track early functional and taxonomic responses to a simulated algal bloom and an oligotrophic control. Using a novel peptide-based enrichment analysis, significant changes (p-value < 0.01) in biological and molecular functions associated with carbon and nitrogen recycling were observed. Within the first day under both organic matter conditions, Bering Strait surface microbiomes increased protein synthesis, carbohydrate degradation, and cellular redox processes while decreasing C1 metabolism. Taxonomic assignments revealed that the core microbiome collectively responded to algal substrates by assimilating carbon before select taxa utilize and metabolize nitrogen intracellularly. Incubations of Chukchi Sea bottom water microbiomes showed similar, but delayed functional responses to identical treatments. Although 24 functional terms were shared between experimental treatments, the timing, and degree of the remaining responses were highly variable, showing that organic matter perturbation directs community functionality prior to alterations to the taxonomic distribution at the microbiome class level. The dynamic responses of these two oceanic microbial communities have important implications for timing and magnitude of responses to organic perturbations within the Arctic Ocean and how community-level functions may forecast biogeochemical gradients in oceans.