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Microbiology

2009

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Articles 1 - 30 of 229

Full-Text Articles in Life Sciences

Proteolytic Regulation Of Toxin-Antitoxin Systems By Clppc In Staphylococcus Aureus, Niles P. Donegan, Earl T. Thompson, Zhibiao Fu, Ambrose L. Cheung Dec 2009

Proteolytic Regulation Of Toxin-Antitoxin Systems By Clppc In Staphylococcus Aureus, Niles P. Donegan, Earl T. Thompson, Zhibiao Fu, Ambrose L. Cheung

Open Dartmouth: Faculty Open Access Scholarship

Bacterial toxin-antitoxin (TA) systems typically consist of a small, labile antitoxin that inactivates a specific longer-lived toxin. In Escherichia coli, such antitoxins are proteolytically regulated by the ATP-dependent proteases Lon and ClpP. Under normal conditions, antitoxin synthesis is sufficient to replace this loss from proteolysis, and the bacterium remains protected from the toxin. However, if TA production is interrupted, antitoxin levels decrease, and the cognate toxin is free to inhibit the specific cellular component, such as mRNA, DnaB, or gyrase. To date, antitoxin degradation has been studied only in E. coli, so it remains unclear whether similar mechanisms of regulation ...


Transcription Analysis Of The Chlorovirus Paramecium Bursaria Chlorella Virus-1, Giane M. Yanai Dec 2009

Transcription Analysis Of The Chlorovirus Paramecium Bursaria Chlorella Virus-1, Giane M. Yanai

Dissertations and Theses in Biological Sciences

Paramecium bursaria chlorella virus (PBCV-1), a member of the family Phycodnaviridae, is a large dsDNA, plaque-forming virus that infects the unicellular green alga Chlorella NC64A. The 331 kb PBCV-1 genome is predicted to encode 365 proteins and 11 tRNAs. To follow global transcription during PBCV-1 replication, a microarray containing 50-mer probes to the PBCV-1 365 protein-encoding genes (CDS) was constructed. Competitive hybridization experiments were conducted employing cDNAs from poly A-containing RNAs obtained from cells at seven time points after virus infection. The results led to the following conclusions: i) the PBCV-1 replication cycle is temporally programmed and regulated; ii) 360 ...


Genetic Effect Of The Dwarfing Genes On Some Culm Characteristics Associatcd With Lodging Resistance In Bread Wheat, Md. Mahbub Hasan Dec 2009

Genetic Effect Of The Dwarfing Genes On Some Culm Characteristics Associatcd With Lodging Resistance In Bread Wheat, Md. Mahbub Hasan

Md. Mahbub Hasan

Due to the challenge of screening traits related to lodging resistance under natural field conditions, selection for lodging resistant varieties in wheat breeding programs is difficult. The identification of easily measurable culm anatomical traits related to lodging resistance would simplify the selection process. The present study was conducted to determine the effect of dwarfing genes on culm anatomical traits related to lodging resistance in our of basal internode 1. Field and laboratory study was conducted in Shahjalal University of Science and Technology, Sylhet, Bangladesh with eight wheat genotypes having Rhr1, Rht2 dwarfing genes in them and a local land race ...


Introducing Mothur: Open-Source, Platform-Independent, Community-Supported Software For Describing And Comparing Microbial Communities, Courtney Robinson Dec 2009

Introducing Mothur: Open-Source, Platform-Independent, Community-Supported Software For Describing And Comparing Microbial Communities, Courtney Robinson

Department of Biology Faculty Publications

mothur aims to be a comprehensive software package that allows users to use a single piece of software to analyze community sequence data. It builds upon previous tools to provide a flexible and powerful software package for analyzing sequencing data. As a case study, we used mothur to trim, screen, and align sequences; calculate distances; assign sequences to operational taxonomic units; and describe the α and β diversity of eight marine samples previously characterized by pyrosequencing of 16S rRNA gene fragments. This analysis of more than 222,000 sequences was completed in less than 2 h with a laptop computer.


Presence And Prevalence Of Viruses In Local And Migratory Honeybees (Apis Mellifera) In Massachusetts, Anna Welch, Francis Drummond, Sunil Tewari, Anne L. Averill, John P. Burand Dec 2009

Presence And Prevalence Of Viruses In Local And Migratory Honeybees (Apis Mellifera) In Massachusetts, Anna Welch, Francis Drummond, Sunil Tewari, Anne L. Averill, John P. Burand

Plant, Soil and Insect Sciences Graduate Student Publication Series

Migratory and local bees in Massachusetts were analyzed for seven viruses. three were detected: black queen cell virus (BQCV), deformed wing virus (DWV), and sacbrood virus (SBV). DWV was most common, followed closely by BQCV and then by SBV. BQCV and SBV were present at significantly higher rates in the migratory bees assayed, bringing into question the impact that these bees have on the health of local bee populations.


Drosophila Adult Eye Model To Teach Scanning Electron Microscopy In An Undergraduate Cell Biology Laboratory, Meghana Tare, Oorvashi Roy Puli, Sarah M. Oros, Amit Singh Dec 2009

Drosophila Adult Eye Model To Teach Scanning Electron Microscopy In An Undergraduate Cell Biology Laboratory, Meghana Tare, Oorvashi Roy Puli, Sarah M. Oros, Amit Singh

Biology Faculty Publications

We have devised an undergraduate laboratory exercise to study tissue morphology using fruit fly, Drosophila melanogaster, as the model organism. Drosophila can be reared in a cost effective manner in a short period of time. This experiment was a part of the undergraduate curriculum of the cell biology laboratory course aimed to demonstrate the use of scanning electron microscopy (SEM) technique to study the morphology of adult eye of Drosophila. The adult eye of Drosophila is a compound eye, which comprises of 800 unit eyes, and serves as an excellent model for SEM studies. We used flies that were mutant ...


“Saccharomyces Cerevisiae G Protein Coupled Receptor, Ste2p Interactions With Its Ligand, Α-Factor And Cognate Gα Protein, Gpa1p, George Kwabena Essien Umanah Dec 2009

“Saccharomyces Cerevisiae G Protein Coupled Receptor, Ste2p Interactions With Its Ligand, Α-Factor And Cognate Gα Protein, Gpa1p, George Kwabena Essien Umanah

Doctoral Dissertations

The Saccharomyces cerevisiae alpha-factor receptor, Ste2p, belongs to the G proteincoupled receptors (GPCRs), a class of integral membrane proteins that are characterized by seven-transmembrane (TM) domains. Ste2p-alpha-factor pair has been used extensively as a paradigm for investigating GPCRs structure and function. Upon binding of alpha-factor to Ste2p, a signal is transduced via an associated guanine-nucleotide binding protein, Gpa1p, initiating a cascade of events similar to those for mammalian GPCRs signal transduction. GPCRs are essential in many physiological processes associated with human diseases. Many aspects of structure and function are highly conserved across GPCRs, irrespective of primary amino acid sequence. This ...


In Vitro Analysis Of The Anti-Influenza Virus Activity Of Pomegranate Products And Fulvic Acid, Radha Ganapathy Dec 2009

In Vitro Analysis Of The Anti-Influenza Virus Activity Of Pomegranate Products And Fulvic Acid, Radha Ganapathy

Masters Theses

In traditional cuban medicine, pomegranate fruits have been used to treat acidosis, dysentery, microbial infections, diarrhoea, helminthiasis; haemorrhage and respiratory pathologies [Vuorela et al., 2003; Roig, 1974; Jimenez et al., 1979; Seoane, 1984].Pomegranates contain high levels of Polyphenolic compounds, which are largely responsible for the fruit’s antioxidant properties. A number of studies have demonstrated that polyphenolic complexes derived from other plants have antiviral effects, suggesting that antiviral activity may also reside in the polyphenol (PP) fraction of pomegranates.

The decay of organic matter generates an extremely heterogeneous mixture of organic molecules referred to as humic substances. They are ...


Formation Of Multiple Dimer Interfaces In The Active And Inactive States Of A Model G Protein-Coupled Receptor, Hee Jung Kim Dec 2009

Formation Of Multiple Dimer Interfaces In The Active And Inactive States Of A Model G Protein-Coupled Receptor, Hee Jung Kim

Doctoral Dissertations

G protein-coupled receptors (GPCRs) are a class of integral membrane receptor proteins that are characterized by seven-transmembrane (7TM) domains connected by intracellular and extracellular loops, an extracellular N-terminus, and an intracellular Cterminus. GPCRs recognize neurotransmitters, sensory molecules and chemotactic agents and are involved in the control of many aspects of metabolism. Since GPCRs play important roles in diverse processes such as pain perception, growth and blood pressure regulation, and viral pathogenesis, GPCRs became important target for therapeutic agents. The tridecapeptide α-factor pheromone (W1H2W3L4Q5L6K7P8G9 ...


Laboratory Models Of Infection And Transmission Of Mycobacterium Ulcerans; Causative Agent Of Buruli Ulcer Disease, Lydia Mosi Dec 2009

Laboratory Models Of Infection And Transmission Of Mycobacterium Ulcerans; Causative Agent Of Buruli Ulcer Disease, Lydia Mosi

Doctoral Dissertations

Identification of the environmental reservoir of Mycobacterium ulcerans, the etiological agent of Buruli ulcer, within the aquatic ecosystem has been a salient research area within the last five years. Based on extensive environmental sampling and elegant laboratory models, associations have been made between the bacterial DNA and aquatic invertebrates, biofilms, plants, fish and detritus material captured on 0.2μm pore filters. These studies have suggested that M. ulcerans is widely distributed within many functional feeding groups and may be concentrated through different trophic links; however, the specific route of transmission to humans remains a mystery. In this study we have ...


Dam Methylation And Putative Fimbriae In Klebsiella Pneumoniae, Joanna Sue Kuehn Dec 2009

Dam Methylation And Putative Fimbriae In Klebsiella Pneumoniae, Joanna Sue Kuehn

Theses and Dissertations

DNA adenine methyltransferase (Dam) plays an important role in different bacterial functions. It has been shown that Dam is required for regulation of bacterial replication initiation and is required for proofreading newly synthesized DNA through methylation directed mismatch repair. Dam is also involved in the regulation of different genes and is required for virulence in several different bacterial genera though its degree of importance depends on the specific bacteria being studied. During this work, a Dam-negative strain (JSM1) was constructed in Klebsiella pneumoniae strain 43816 to ascertain its importance for K. pneumoniae viability and virulence.

To test JSM1 for expression ...


Expression Of The Major Surface Protease (Msp) Of Leishmania Chagasi, Patricia Ann Storlie Dec 2009

Expression Of The Major Surface Protease (Msp) Of Leishmania Chagasi, Patricia Ann Storlie

Theses and Dissertations

Leishmania chagasi is the causative agent of visceral leishmaniasis in South America. The most abundant glycoprotein on the surface of L. chagasi promastigotes is the glycosylphosphatidylinositol (GPI) anchored protease MSP (major surface protease), also called GP63. MSP is encoded by more than 18 tandem MSP genes on a single chromosome. MSP genes are classified according to unique sequences at their 3' ends and distinct expression patterns. The five MSPS genes (MSPS1, MSPS2, etc.) express 3.0 kb RNAs in stationary phase of promastigote growth in vitro in culture. The > twelve MSPL genes express 2.7 kb RNAs in logarithmic phase ...


The Positive Regulation Of Hiv-1 Vif Mrna Splicing Is Required For Efficient Virus Replication, Colin Michael Exline Dec 2009

The Positive Regulation Of Hiv-1 Vif Mrna Splicing Is Required For Efficient Virus Replication, Colin Michael Exline

Theses and Dissertations

Productive HIV-1 transcription yields a single ∼­9.2kb RNA. From this ∼9.2kb genomic RNA, greater than 40 different subgenomic mRNAs can be produced through alternative splicing using four 5' splice sites (ss) and seven 3'ss. Splice site utilization is governed by the inherent strength of the splice sites and by several identified cis acting elements. The HIV-1 Vif protein, required to overcome the cellular antiviral factor APOBEC3G, is encoded by a singly-spliced mRNA coupling 5'ss D1 to 3'ss A1. Alternatively, mRNAs spliced at A1 can utilize a downstream 5'ss, D2, resulting in inclusion of non-coding ...


Crda Regulates Endogenous Beta-Lactamase Activity In Myxococcus Xanthus, Di Li Dec 2009

Crda Regulates Endogenous Beta-Lactamase Activity In Myxococcus Xanthus, Di Li

Theses and Dissertations

No abstract provided.


Identification Of Ebola Glycoprotein Mutants That Exhibit Increased Transduction Efficiency, Lindsay Marie Sandersfeld Dec 2009

Identification Of Ebola Glycoprotein Mutants That Exhibit Increased Transduction Efficiency, Lindsay Marie Sandersfeld

Theses and Dissertations

Gene delivery via lentiviruses can yield long term expression of transgenes. Specificity of host cell targeting by viral vectors occurs primarily through viral glycoprotein (GP)/cellular receptor interactions. Ebola virus (EBOV) GP has broad tropism for a variety of cell types making this viral GP a potentially useful reagent for delivery of gene therapy. However, titers of EBOV GP pseudotyped lentiviruses are insufficient for practical use in clinical applications. Enhancement of EBOV-GP pseudotyped titers by as little as half a log might yield clinically applicable titers.

In an alanine scanning study, we identified 19 residues in EBOV-GP1 that increased transduction ...


Coping With Stress: Anaerobic Respiratory And Oxidative Stress Tolerance Mechanisms Are Critical For Neisseria Gonorrhoeae Biofilm Formation, Megan Lindsay Falsetta Wood Dec 2009

Coping With Stress: Anaerobic Respiratory And Oxidative Stress Tolerance Mechanisms Are Critical For Neisseria Gonorrhoeae Biofilm Formation, Megan Lindsay Falsetta Wood

Theses and Dissertations

Many illnesses and infections are exacerbated and/or caused by biofilms. Neisseria gonorrhoeae, the etiologic agent of gonorrhea, is frequently asymptomatic in women, which can lead to persistent infection. Persistent infection can result in pelvic inflammatory disease, tubo-ovarian abscesses, infertility, and ectopic pregnancy. N. gonorrhoeae has been shown to form biofilms over glass, primary and immortalized cervical cells, and during natural cervical infection. Asymptomatic infection occurs in only 1% of infected males, and the infection site is subject to periodic rapid fluid flow, which may limit biofilm formation. Thus, biofilm formation may specifically play an important role in the infection ...


Gene Expression Profile Of Tumor Cell-Fused Or Noni (Morinda Citrifolia)-Treated Dendritic Cells, Melissa O'Connor Dec 2009

Gene Expression Profile Of Tumor Cell-Fused Or Noni (Morinda Citrifolia)-Treated Dendritic Cells, Melissa O'Connor

All Dissertations

Dendritic cell-mediated cancer immunotherapy employs several ways to engage tumor antigens. We have demonstrated both in pre-clinical animal studies and early clinical trials that dendritomas, highly purified hybrids between dendritic cells and tumor cells, are superior activators of anti-tumor immunity. In the present study, we examined the expression profile of several inflammatory chemokine and chemokine receptors of dendritomas by RNA microarray and real-time RT-PCR. The results indicate that dendritomas made from immature DCs and tumor cells express higher levels of CCL3, CCL5, and CCL22 and lower levels of CCR2 and CCR5, which mimics LPS matured DCs, while dendritomas made from ...


Sequence Analysis And Characterization Of The Dihydrodiol Dehydrogenase And Aldehyde Dehydrogenase Genes In'' Sphingomonas Paucimobilis'' Epa505, Jaleh Jalili Dec 2009

Sequence Analysis And Characterization Of The Dihydrodiol Dehydrogenase And Aldehyde Dehydrogenase Genes In'' Sphingomonas Paucimobilis'' Epa505, Jaleh Jalili

All Dissertations

A bacterial artificial chromosome (BAC) library was previously constructed from genomic DNA of Sphingomonas paucimobilis EPA505 at Clemson University Genomic institute (CUGI). To isolate and identify the bphB gene from the genome of S. paucimobilis EPA505, a set of primers was designed based on conserved regions of the bphB gene encoding dihydrodiol dehydrogenase of Sphingomonas CHY-1 and Sphingomonas yanoikuyae B1. Routine PCR was performed and a PCR fragment of approximately 500 bp that confirmed the presence of pbhB gene in Sphingomonas paucimobilis EPA505 was produced. Hybridization of the PCR product with BAC library was performed and one hundred two positive ...


Prevalence And Biological Control Of Salmonella Contamination In Rendering Plant Environments And The Finished Rendered Meals, Brandon Kinley Dec 2009

Prevalence And Biological Control Of Salmonella Contamination In Rendering Plant Environments And The Finished Rendered Meals, Brandon Kinley

All Dissertations

Although the rendering process serves as invaluable means for the disposal of inedible animal by-products, the finished products often harbor pathogenic and opportunistic microorganisms such as Salmonella and enterococci, respectively. The temperatures used during the rendering process far exceed the heat tolerance threshold of most bacterial species, so cross-contamination from the environment and/or from the incoming raw material is the proposed source of the contamination. Research has demonstrated that the raw material coming into the rendering facility is highly contaminated with pathogenic bacteria including Salmonella. While not in a rendering facility, studies have also demonstrated that bacteria such as ...


Environmental Implications Of Francisella Tularensis Biofilms, Jeffrey J. Margolis '00 Dec 2009

Environmental Implications Of Francisella Tularensis Biofilms, Jeffrey J. Margolis '00

Doctoral Dissertations

Francisella tularensis survives in one of the widest environmental ranges of any pathogen. Numerous mammals and arthropod vectors are infected by this highly virulent organism. How this zoonotic pathogen persists outside of its many hosts remains unexplored. We aimed to examine how F. tularensis interacts with environmental surfaces, and hypothesized that biofilm formation may enable survival of this organism in nature. By understanding the role these surface-attached bacterial communities play in F. tularensis ecology, we hope to gain insight into the mechanisms of environmental persistence and transmission of this pathogen.

We identify chitin as a potential non-host niche for F ...


Examining The Regulation Of Virulence Factors In Francisella Tularensis, Blake Wade Buchan Dec 2009

Examining The Regulation Of Virulence Factors In Francisella Tularensis, Blake Wade Buchan

Theses and Dissertations

F. tularensis is an intracellular pathogen, and is the causative agent of tularemia in humans. The ability of F. tularensis to parasitize host cells is largely dependent upon genes within a pathogenicity island (FPI), including those in the iglABCD operon. Specific mechanisms and gene products involved in regulation of the FPI are not well understood. I initiate the study of this regulatory system by creating an efficient Tn5-based mutagenesis system optimized for use in F. tularensis, and utilize this system to construct a lacZ reporter library. I identify genes differentially regulated in response to growth on two different media, including ...


Erk 1/2 And P38 Mapk Pathways Are Both Invovled In The Expression Of Interleukin-6, -8, And Cyclooxygenase-2 In Thrombocytes Stimulated With Lipopolysaccharide, Candace Hitchcock Dec 2009

Erk 1/2 And P38 Mapk Pathways Are Both Invovled In The Expression Of Interleukin-6, -8, And Cyclooxygenase-2 In Thrombocytes Stimulated With Lipopolysaccharide, Candace Hitchcock

All Theses

This study was conducted to determine if the p38 and ERK1/2 MAPK pathways are involved in transcription of IL-6, IL-8, and COX-2 in the chicken thrombocyte response to ligation of Toll-like receptor 4 (TLR4) by Salmonella minnesota lipopolysaccharide (LPS). Thrombocytes were isolated and subsequently treated with either p38 MAPK or ERK inhibitor, and then with LPS during in vitro cell culture. Transcription of IL-6, IL-8, and COX-2 mRNA was determined using real-time PCR. The experiments were repeated using pM, nM and μM concentrations of both inhibitors to test cell sensitivity. Stimulation with LPS induced expression of IL-6, IL-8 and ...


Designing An Instrument Based Nn Native Fluorescence To Determine Soil Microbial Content At A Mars Analog Site, Heather D. Smith Dec 2009

Designing An Instrument Based Nn Native Fluorescence To Determine Soil Microbial Content At A Mars Analog Site, Heather D. Smith

All Graduate Theses and Dissertations

For this research project we designed an instrument to detect bacteria via biomolecular fluorescence. We introduce the current understanding of astrobiology, our knowledge of life beyond Earth, and the commonality of Earth life as it pertains to the search for life on Mars. We proposed a novel technique for searching for direct evidence of life on the surface of Mars using fluorescence. We use the arid region of the Mojave Desert as an analog of Mars. Results indicate the fluorescence of the biotic component of desert soils is approximately as strong as the fluorescence of the mineral component. Fluorescence laboratory ...


Francisella Tularensis Type A Strains Cause The Rapid Encystment Of Acanthamoeba Castellanii And Survive In Amoebal Cysts For Three Weeks Postinfection, Jeffrey J. Margolis, Sahar H. El-Etr, Denise Monack, Richard A. Robinson, Marissa Cohen, Emily Moore, Amy Rasley Nov 2009

Francisella Tularensis Type A Strains Cause The Rapid Encystment Of Acanthamoeba Castellanii And Survive In Amoebal Cysts For Three Weeks Postinfection, Jeffrey J. Margolis, Sahar H. El-Etr, Denise Monack, Richard A. Robinson, Marissa Cohen, Emily Moore, Amy Rasley

Jeffrey Margolis

Francisella tularensis, the causative agent of the zoonotic disease tularemia, has recently gained increased
attention due to the emergence of tularemia in geographical areas where the disease has been previously
unknown and to the organism’s potential as a bioterrorism agent. Although F. tularensis has an extremely
broad host range, the bacterial reservoir in nature has not been conclusively identified. In this study, the ability
of virulent F. tularensis strains to survive and replicate in the amoeba Acanthamoeba castellanii was explored.
We observe that A. castellanii trophozoites rapidly encyst in response to F. tularensis infection and that this
rapid encystment ...


Bpv Entry And Trafficking In Ebtr Cells, Enkhmart Dudleenamjil Nov 2009

Bpv Entry And Trafficking In Ebtr Cells, Enkhmart Dudleenamjil

Theses and Dissertations

Bovine Parvovirus (BPV) belongs to the genus Bocavirus, family Parvoviridae. BPV is the leading etiologic agent among the pathogens that cause primary gastroenteritis of cattle. Many of the intracellular events associated with virus replication are unknown. In this research project, we investigated BPV internalization into the host cell and trafficking in the cytosol. Preliminarily, EBTr cells had abundant clathrin, virus attached to purified clathrin, and EM micrographs revealed virus in endocytic vacuoles. Assays detecting virus infectivity (i.e. viral protein synthesis), virus production (completion of the replication cycle), and quantitative PCR (qPCR) to detect viral transcripts were used to evaluate ...


Part 1: Screening Of Thirty-One Medicinal Plant Species Against Herpes Simplex Virus, Acetone And Methanol Extracts From The Root Tissue Of Kalanchoe Pinnata Interferes With Hsv Types 1 And 2 Dna Replication And Early And Late Gene Expression Preventing The Spread Of Hsv In Vitro. Part 2: Professional Development Curriculum: Integrating Molecular Biology And Microbiology Into The Existing Secondary Biology Curricula, Mary Ruth Greer Nov 2009

Part 1: Screening Of Thirty-One Medicinal Plant Species Against Herpes Simplex Virus, Acetone And Methanol Extracts From The Root Tissue Of Kalanchoe Pinnata Interferes With Hsv Types 1 And 2 Dna Replication And Early And Late Gene Expression Preventing The Spread Of Hsv In Vitro. Part 2: Professional Development Curriculum: Integrating Molecular Biology And Microbiology Into The Existing Secondary Biology Curricula, Mary Ruth Greer

Theses and Dissertations

PART 1: Thirty-one medicinal plant species from Hawaii, Morocco, and the Sonoran Desert, USA have been shown in past studies to be highly inhibitory to pathogenic bacteria, fungi, and certain cancer cell lines. However, none were tested for antiviral activity. Acetone and methanol extracts from these species were bio-assayed for antiviral activity against herpes simplex virus types 1 and 2 (HSV 1 and HSV 2) and for cytotoxicity to the Vero C1008 cell line. Extracts from these species were tested in vitro for antiviral activity using an immunoperoxidase mini-plaque reduction assay to detect viral structural protein synthesis. Sulforhodamine B and ...


Levels Of The Secreted Vibrio Cholerae Attachment Factor Gbpa Are Modulated By Quorum-Sensing-Induced Proteolysis, Brooke A. Jude, Raquel M. Martinez, Karen Skorupski, Ronald K. Taylor Nov 2009

Levels Of The Secreted Vibrio Cholerae Attachment Factor Gbpa Are Modulated By Quorum-Sensing-Induced Proteolysis, Brooke A. Jude, Raquel M. Martinez, Karen Skorupski, Ronald K. Taylor

Open Dartmouth: Faculty Open Access Scholarship

Vibrio cholerae is the etiologic agent of cholera in humans. Intestinal colonization occurs in a stepwise fashion, initiating with attachment to the small intestinal epithelium. This attachment is followed by expression of the toxin-coregulated pilus, microcolony formation, and cholera toxin (CT) production. We have recently characterized a secreted attachment factor, GlcNAc binding protein A (GbpA), which functions in attachment to environmental chitin sources as well as to intestinal substrates. Studies have been initiated to define the regulatory network involved in GbpA induction. At low cell density, GbpA was detected in the culture supernatant of all wild-type (WT) strains examined. In ...


Human Uterine Natural Killer Cells But Not Blood Natural Killer Cells Inhibit Human Immunodeficiency Virus Type 1 Infection By Secretion Of Cxcl12, Teddy F. Mselle, Aexandra L. Howell, Mimi Ghosh, Charles R. Wira, Charles L. Sentman Nov 2009

Human Uterine Natural Killer Cells But Not Blood Natural Killer Cells Inhibit Human Immunodeficiency Virus Type 1 Infection By Secretion Of Cxcl12, Teddy F. Mselle, Aexandra L. Howell, Mimi Ghosh, Charles R. Wira, Charles L. Sentman

Open Dartmouth: Faculty Open Access Scholarship

Natural killer (NK) cells derived from the human female reproductive tract (FRT) are phenotypically and functionally distinct from those obtained from peripheral blood. Because the FRT is a primary site of human immunodeficiency virus type 1 (HIV-1) infection in women, we determined whether soluble factors secreted by uterine-derived NK (uNK) cells inhibit HIV-1 infection. Clonal populations of uNK cells were activated with interleukin-12 (IL-12) and IL-15, and conditioned media (CM) from these cultures evaluated for their ability to inhibit infection of cells by HIV-1IIIB, HIV-1NL4.3, and HIV-1HC4 (X4-tropic) or HIV-1BaL (R5-tropic) viruses. We found that ...


Antimicrobial Evaluation Of Novel Fatty Acid Derivatives And Other Natural Antimicrobials, Patricia Nobmann Nov 2009

Antimicrobial Evaluation Of Novel Fatty Acid Derivatives And Other Natural Antimicrobials, Patricia Nobmann

Doctoral

The food industry has shown increased interest for novel natural antimicrobials due to consumer demand for foods with fewer synthetic additives, increased safety, quality and shelf-life. Concurrently, the emergence of drug resistant bacteria substantiates the need for newer antimicrobial agents. Alternative strategies include the use of novel antimicrobials, such as fatty acid derivatives, essential oils and bacteriocins, with proven antimicrobial properties against a diverse range of bacteria. This study investigated novel carbohydrate fatty acid (CF A) derivatives for their antibacterial activity against a range of pathogenic and spoilage bacteria. A series of mono-substituted CF A derivatives using lauric and caprylic ...


Biomarker Changes Associated With Tuberculin Skin Test (Tst) Conversion: A Two-Year Longitudinal Follow-Up Study In Exposed Household Contacts, Rabia Hussain, Najeeha Talat, Firdaus Shahid, Ghaffar Dawood Oct 2009

Biomarker Changes Associated With Tuberculin Skin Test (Tst) Conversion: A Two-Year Longitudinal Follow-Up Study In Exposed Household Contacts, Rabia Hussain, Najeeha Talat, Firdaus Shahid, Ghaffar Dawood

Department of Pathology and Laboratory Medicine

Background:A high prevalence (50-80%) of Tuberculin Skin Test Positivity (TST+ >or=10 mm indurations) has been reported in TB endemic countries. This pool forms a huge reservoir for new incident TB cases. However, immune biomarkers associated with TST conversion are largely unknown. The objective of this study was to identify immune biomarkers associated with TST conversion after acute Mycobacterium tuberculosis (MTB)
Methodology/Principal Findings:A 24 month longitudinal study was carried out in a recently MTB exposed cohort of household contacts (HC = 93, 75% TST+). Control group consisted of unexposed community controls (EC = 59, 46%TST+). Cytokine secretion was ...