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Articles 5851 - 5880 of 8404

Full-Text Articles in Microbiology

Hpai H5n1: A Global Pandemic Concern, With Implications For Pandemic Preperation And Public Health Policy, Lauren M. Koontz Jan 2013

Hpai H5n1: A Global Pandemic Concern, With Implications For Pandemic Preperation And Public Health Policy, Lauren M. Koontz

Browse all Theses and Dissertations

Research on highly pathogenic avian influenza A (HPAI) H5N1 has gained much attention in recent years due to its devastating impact within the bird population. While transmission to humans is rare, infections are fatal in more than half of the cases. One of the main concerns among the scientific community is the ability for this virus to mutate in a way much like seasonal influeanza that would allow it to be transmitted efficiently among the human population. Two researchers were able to separately create mutant isolates of H5N1 influenza A virus that could be transmitted via the respiratory route between …


Malnutrition In Sickle Cell Anemia: Implications For Infection, Growth And Maturation, Hyacinth I. Hyacinth, Oluwatoyosi A. Adekeye, Christopher S. Yilgwan Jan 2013

Malnutrition In Sickle Cell Anemia: Implications For Infection, Growth And Maturation, Hyacinth I. Hyacinth, Oluwatoyosi A. Adekeye, Christopher S. Yilgwan

Journal of Social, Behavioral, and Health Sciences

Sickle cell anemia (SCA) is a genetic disease that affects mostly individuals of African and/or Hispanic descent, with the majority of cases in sub-Saharan Africa. Individuals with this disease show slowed growth, delayed sexual maturity, and poor immunologic function. These complications could partly be explained by the state of undernutrition associated with the disease. Proposed mechanism of undernutrition include protein hypermetabolism, decreased dietary intake possibly from interleukin-6-related appetite suppression, increased cardiac energy demand/expenditure, and increased red cell turnover. All the above mechanisms manifest as increased resting energy expenditure. Nutritional intervention utilizing single or multiple nutrient supplementation has led to improved …


Neisseria Oralis Sp. Nov., Isolated From Healthy Gingival Plaque And Clinical Samples, William J. Wolfgang, Teresa V. Passaretti, Reashma Jose, Jocelyn Cole, An Coorevits, Andrea N. Carpenter, Sherly Jose, Anita Van Landschoot, Jacques Izard, Donna J. Kohlerschmidt, Peter Vandamme, Floyd E. Dewhirst, Mark A. Fisher, Kimberlee A. Musser Jan 2013

Neisseria Oralis Sp. Nov., Isolated From Healthy Gingival Plaque And Clinical Samples, William J. Wolfgang, Teresa V. Passaretti, Reashma Jose, Jocelyn Cole, An Coorevits, Andrea N. Carpenter, Sherly Jose, Anita Van Landschoot, Jacques Izard, Donna J. Kohlerschmidt, Peter Vandamme, Floyd E. Dewhirst, Mark A. Fisher, Kimberlee A. Musser

Department of Food Science and Technology: Faculty Publications

A polyphasic analysis was undertaken of seven independent isolates of gram-negative cocci collected from pathological clinical samples from New York, Louisiana, Florida, and Illinois and healthy subgingival plaque from a patient in Virginia, USA. The 16S rRNA gene sequence similarity among these isolates was 99.7–100 %, and the closest species with a validly published name was Neisseria lactamica (96.9 % similarity to the type strain). DNA–DNA hybridization confirmed that these isolates are of the same species and are distinct from their nearest phylogenetic neighbor, N. lactamica. Phylogenetic analysis of 16S and 23S rRNA gene sequences indicated that the …


Towards Defining The Chloroviruses: A Genomic Journey Through A Genus Of Large Dna Viruses, Adrien Jeanniard, David D. Dunigan, James Gurnon, Irina V. Agarkova, Ming Kang, Jason Vitek, Garry Duncan, O William Mcclung, Megan Larsen, Jean-Michel Claverie, James L. Van Etten, Guillaume Blanc Jan 2013

Towards Defining The Chloroviruses: A Genomic Journey Through A Genus Of Large Dna Viruses, Adrien Jeanniard, David D. Dunigan, James Gurnon, Irina V. Agarkova, Ming Kang, Jason Vitek, Garry Duncan, O William Mcclung, Megan Larsen, Jean-Michel Claverie, James L. Van Etten, Guillaume Blanc

Nebraska Center for Virology: Faculty Publications

Background: Giant viruses in the genus Chlorovirus (family Phycodnaviridae) infect eukaryotic green microalgae. The prototype member of the genus, Paramecium bursaria chlorella virus 1, was sequenced more than 15 years ago, and to date there are only 6 fully sequenced chloroviruses in public databases. Presented here are the draft genome sequences of 35 additional chloroviruses (287 – 348 Kb/319 – 381 predicted protein encoding genes) collected across the globe; they infect one of three different green algal species. These new data allowed us to analyze the genomic landscape of 41 chloroviruses, which revealed some remarkable features about these viruses. …


Evaluation Of Higher Plant Virus Resistance Genes In The Green Alga, Chlorella Variabilis Nc64a, During The Early Phase Of Infection With Paramecium Bursaria Chlorella Virus-1, Janet M. Rowe, David D. Dunigan, Guillaume Blanc, James R. Gurnon, Yuannan Xia, James L. Van Etten Jan 2013

Evaluation Of Higher Plant Virus Resistance Genes In The Green Alga, Chlorella Variabilis Nc64a, During The Early Phase Of Infection With Paramecium Bursaria Chlorella Virus-1, Janet M. Rowe, David D. Dunigan, Guillaume Blanc, James R. Gurnon, Yuannan Xia, James L. Van Etten

Nebraska Center for Virology: Faculty Publications

With growing industrial interest in algae plus their critical roles in aquatic systems, the need to understand the effects of algal pathogens is increasing. We examined a model algal host–virus system, Chlorella variabilis NC64A and virus, PBCV-1. C. variabilis encodes 375 homologs to genes involved in RNA silencing and in response to virus infection in higher plants. Illumina RNA-Seq data showed that 325 of these homologs were expressed in healthy and early PBCV-1 infected (≤60 min) cells. For each of the RNA silencing genes to which homologs were found, mRNA transcripts were detected in healthy and infected cells. C. variabilis …


A Twin-Cysteine Motif In The V2 Region Of Gp120 Is Associated With Siv Envelope Trimer Stabilization, Christopher Bohl, Dane Bowder, Jesse Thompson, Levon Abrahamyan, Sandra Gonzalez-Ramirez, Youdong Mao, Joseph Sodroski, Charles Wood, Shi-Hua Xiang Jan 2013

A Twin-Cysteine Motif In The V2 Region Of Gp120 Is Associated With Siv Envelope Trimer Stabilization, Christopher Bohl, Dane Bowder, Jesse Thompson, Levon Abrahamyan, Sandra Gonzalez-Ramirez, Youdong Mao, Joseph Sodroski, Charles Wood, Shi-Hua Xiang

Nebraska Center for Virology: Faculty Publications

The V1 and V2 variable regions of the primate immunodeficiency viruses contribute to the trimer association domain of the gp120 exterior envelope glycoprotein. A pair of V2 cysteine residues at 183 and 191 (‘‘twin cysteines’’) is present in several simian immunodeficiency viruses, human immunodeficiency virus type 2 (HIV-2) and some SIVcpz lineages, but not in HIV-1. To examine the role of this potentially disulfide-bonded twin-cysteine motif, the cysteine residues in the SIVmac239 envelope glycoproteins were individually and pairwise substituted by alanine residues. All of the twin-cysteine mutants exhibited decreases in gp120 association with the Env trimer, membrane-fusing activity, and …


Hiv-1 Env C2-V4 Diversification In A Slow-Progressor Infant Reveals A Flat But Rugged Fitness Landscape, S. Abigail Smith, Charles Wood, John T. West Jan 2013

Hiv-1 Env C2-V4 Diversification In A Slow-Progressor Infant Reveals A Flat But Rugged Fitness Landscape, S. Abigail Smith, Charles Wood, John T. West

Nebraska Center for Virology: Faculty Publications

Human immunodeficiency virus type-1 (HIV-1) fitness has been associated with virus entry, a process mediated by the envelope glycoprotein (Env). We previously described Env genetic diversification in a Zambian, subtype C infected, slow-progressor child (1157i) in parallel with an evolving neutralizing antibody response. Because of the role the Variable-3 loop (V3) plays in transmission, cell tropism, neutralization sensitivity, and fitness, longitudinally isolated 1157i C2-V4 alleles were cloned into HIV-1NL4-3-eGFP and -DsRed2 infectious molecular clones. The fluorescent reporters allowed for dual-infection competitions between all patient-derived C2-V4 chimeras to quantify the effect of V3 diversification and selection on fitness. ‘Winners’ …


‘‘Megavirales’’, A Proposed New Order For Eukaryotic Nucleocytoplasmic Large Dna Viruses, Philippe Colson, Xavier De Lamballerie, Natalya Yutin, Sassan Asgari, Yves Bigot, Dennis K. Bideshi, Xiao-Wen Cheng, Brian A. Federici, James L. Van Etten, Eugene V. Koonin, Bernard La Scola, Didier Raoult Jan 2013

‘‘Megavirales’’, A Proposed New Order For Eukaryotic Nucleocytoplasmic Large Dna Viruses, Philippe Colson, Xavier De Lamballerie, Natalya Yutin, Sassan Asgari, Yves Bigot, Dennis K. Bideshi, Xiao-Wen Cheng, Brian A. Federici, James L. Van Etten, Eugene V. Koonin, Bernard La Scola, Didier Raoult

Nebraska Center for Virology: Faculty Publications

The nucleocytoplasmic large DNA viruses (NCLDVs) comprise a monophyletic group of viruses that infect animals and diverse unicellular eukaryotes. The NCLDV group includes the families Poxviridae, Asfarviridae, Iridoviridae, Ascoviridae, Phycodnaviridae, Mimiviridae and the proposed family ‘‘Marseilleviridae’’. The family Mimiviridae includes the largest known viruses, with genomes in excess of one megabase, whereas the genome size in the other NCLDV families varies from 100 to 400 kilobase pairs. Most of the NCLDVs replicate in the cytoplasm of infected cells, within so-called virus factories. The NCLDVs share a common ancient origin, as demonstrated by evolutionary reconstructions that trace approximately 50 genes encoding …


Recent Advances On The Use Of Structural Biology For The Design Of Novel Envelope Immunogens Of Hiv-1, Shi-Hua Xiang Jan 2013

Recent Advances On The Use Of Structural Biology For The Design Of Novel Envelope Immunogens Of Hiv-1, Shi-Hua Xiang

Nebraska Center for Virology: Faculty Publications

Many efforts have been made in the worldwide quest for a prophylactic HIV vaccine to end the AIDS pandemic, but none has yet succeeded. The lessons learned have repeatedly informed us that the traditional or conventional approaches directly using the pathogens or subunits will not be sufficient for an effective HIV/AIDS vaccine. Recent advances in structure-based technology have shown some promise in the quest for a better immunogen in HIV vaccine development. According to the basic binding structural relationship of an antigen and an antibody, structure-based antigen design could bring some hope for the development of an effective vaccine against …


The Highly Conserved Layer-3 Component Of The Hiv-1 Gp120 Inner Domain Is Critical For Cd4-Required Conformational Transitions, Anik Désormeaux, Mathieu Coutu, Halima Medjahed, Beatriz Pacheco, Alon Herschhorn, Christopher Gu, Shi-Hua Xiang, Youdong Mao, Joseph Sodroski, Andrés Finzi Jan 2013

The Highly Conserved Layer-3 Component Of The Hiv-1 Gp120 Inner Domain Is Critical For Cd4-Required Conformational Transitions, Anik Désormeaux, Mathieu Coutu, Halima Medjahed, Beatriz Pacheco, Alon Herschhorn, Christopher Gu, Shi-Hua Xiang, Youdong Mao, Joseph Sodroski, Andrés Finzi

Nebraska Center for Virology: Faculty Publications

The trimeric envelope glycoprotein (Env) of human immunodeficiency virus type 1 (HIV-1) mediates virus entry into host cells. CD4 engagement with the gp120 exterior envelope glycoprotein subunit represents the first step during HIV-1 entry. CD4-induced conformational changes in the gp120 inner domain involve three potentially flexible topological layers (layers 1, 2, and 3). Structural rearrangements between layer 1 and layer 2 have been shown to facilitate the transition of the envelope glycoprotein trimer from the unliganded to the CD4-bound state and to stabilize gp120-CD4 interaction. However, our understanding of CD4-induced conformational changes in the gp120 inner domain remains incomplete. Here, …


Analysis Of Primary Resistance Mutations To Hiv-1 Entry Inhibitors In Therapy Naive Subtype C Hiv-1 Infected Mother– Infant Pairs From Zambia, Hongyan Guo, Chang Liu, Bin Liu, Charles Wood, Xiaohong Kong Jan 2013

Analysis Of Primary Resistance Mutations To Hiv-1 Entry Inhibitors In Therapy Naive Subtype C Hiv-1 Infected Mother– Infant Pairs From Zambia, Hongyan Guo, Chang Liu, Bin Liu, Charles Wood, Xiaohong Kong

Nebraska Center for Virology: Faculty Publications

Background—Small molecular CCR5 inhibitors represent a new class of drugs for treating HIV-1 infection. The evaluation of the primary resistance mutations associated with entry inhibitors during HIV-1 perinatal transmission is required because they may have a profound impact on the clinical management in MTCT.

Objectives—To evaluate the primary resistance mutations to maraviroc and vicriviroc during perinatal transmission and analyze the sensitivity of Env derived from mother–infant pairs to maraviroc.

Study design—Nine MIPs infected by subtype C HIV-1 were recruited to analyze the prevalence and transmission of primary resistance mutations to maraviroc and vicriviroc. Moreover, Env derived from six MIPs were …


Early Childhood Infection Of Kaposi’S Sarcoma-Associated Herpesvirus In Zambian Households: A Molecular Analysis, Landon Olp, Danielle M. Shea, Maxine K. White, Clement Gondwe, Chipepo Kankasa, Charles Wood Jan 2013

Early Childhood Infection Of Kaposi’S Sarcoma-Associated Herpesvirus In Zambian Households: A Molecular Analysis, Landon Olp, Danielle M. Shea, Maxine K. White, Clement Gondwe, Chipepo Kankasa, Charles Wood

Nebraska Center for Virology: Faculty Publications

Sub-Saharan Africa is endemic for Kaposi’s sarcoma-associated herpesvirus (KSHV) and there is a high rate of early childhood infection; however, the transmission sources are not well characterized. We examined household members as potential KSHV transmission sources to young children in the KSHV-endemic country of Zambia. To this end, we enrolled and followed Zambian households with at least one KSHV-seropositive child and collected longitudinal buccal swab samples. KSHV burden was evaluated and K1 sequences from the children were determined and analyzed for differences to K1 sequences from household members. The K1 sequences were also analyzed for evolution over time. We generated …


Histone Biotinylation In Candida Albicans, Sahar Hasim, Swetha Tati, Nandakumar Madayiputhiya, Renu Nandakumar, Kenneth W. Nickerson Jan 2013

Histone Biotinylation In Candida Albicans, Sahar Hasim, Swetha Tati, Nandakumar Madayiputhiya, Renu Nandakumar, Kenneth W. Nickerson

Kenneth Nickerson Papers

Candida albicans is an opportunistic fungal pathogen in humans. It is a polymorphic fungus: it can live as yeasts, hyphae, or pseudohyphae. Biotin is required for cell growth and fatty acid metabolism because it is used as a cofactor for carboxylases such as acetyl-CoA carboxylase, and pyruvate carboxylase. In addition, we have discovered that biotin is used to modify histones in C. albicans. Biotinylation was detected by Western blots using a monoclonal antibiotin HRP-conjugated antibody as well as with qTOF and LC/MS/MS mass spectrometry. As a precaution, the antibiotin antibody was dialyzed against neutravidin prior to use. During this study, …


Seroprevalence Of Brucellosis In Livestock Within Three Endemic Regions Of The Country Of Georgia, Eliso Mamisashvili, Ian T. Kracalik, Tinatin Onashvili, Lela Kerdzevadze, Ketevan Goginashvili, Tamar Tigilauri, Marina Donduashvili, Marina Nikolaishvili, Irma Beradze, Marina Zakareishvili, Maka Kokhreidze, Makvala Gelashvili, Nino Vepkhvadze, S. Elizabeth Rácz, Philip H. Elzer, Mikeljon P. Nikolich, Jason K. Blackburn Jan 2013

Seroprevalence Of Brucellosis In Livestock Within Three Endemic Regions Of The Country Of Georgia, Eliso Mamisashvili, Ian T. Kracalik, Tinatin Onashvili, Lela Kerdzevadze, Ketevan Goginashvili, Tamar Tigilauri, Marina Donduashvili, Marina Nikolaishvili, Irma Beradze, Marina Zakareishvili, Maka Kokhreidze, Makvala Gelashvili, Nino Vepkhvadze, S. Elizabeth Rácz, Philip H. Elzer, Mikeljon P. Nikolich, Jason K. Blackburn

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Brucellosis is the one of most common livestock zoonoses in Georgia, resulting in significant economic losses. Livestock were sampled in three regions of Georgia (Kakheti, Kvemo Kartli, Imereti). Districts that historically reported high numbers of brucellosis related morbidity were selected for serological, bacteriological and molecular surveys. Surveying efforts yielded samples from 10,819 large and small ruminants. In total, 735 serological tests were positive on Rose Bengal and 33 bacterial isolates were recovered and identified as Brucella melitensis or Brucella abortus by microbiology and AMOS-PCR. A Bayesian framework was implemented to estimate the true prevalence of the disease given an imperfect …


Arbovirus Persistence And Selection Of Persistent Variants Following Chronic Infection In Aedine Mosquitoes: A Comparative Study Between Ae. Aegypti And Ae. Albopictus 30 Days Post Infection With Sindbis Virus, Zoe Leah Lyski Jan 2013

Arbovirus Persistence And Selection Of Persistent Variants Following Chronic Infection In Aedine Mosquitoes: A Comparative Study Between Ae. Aegypti And Ae. Albopictus 30 Days Post Infection With Sindbis Virus, Zoe Leah Lyski

UNF Graduate Theses and Dissertations

In the present investigation two container breeding mosquitoes, Aedes aegypti and Aedes albopictus were exposed to Sindbis virus (SINV). Mosquitoes were proffered a viremic bloodmeal using a vertical membrane feeder in an attempt to infect females while preserving virus-gut interactions that are speculated to be responsible for amplification and selective roles encountered in nature. Cohorts of 50 mosquitoes of each species were exposed to SINV strain TR339 or EMEM in a bloodmeal and incubated in insectary conditions for 30 days. Once infected, the mosquito remains persistently infected for life, accumulating mutations in the virus RNA genome. Plaque size variants may …


Optimizing Electrode Design For Microbial Fuel Cells Used For Wastewater Treatment, Lindsay Nichols, John A. Hogan Jan 2013

Optimizing Electrode Design For Microbial Fuel Cells Used For Wastewater Treatment, Lindsay Nichols, John A. Hogan

STAR Program Research Presentations

Microbial fuel cells (MFC) utilize bacteria to generate an electrical current that can be used in the decomposition of sludge and human urine. In a MFC there is an anode (for oxidation of organic compounds), cathode (reduction of oxygen or carbon dioxide), and a proton exchange membrane (PEM, allows protons to migrate); reduction-oxidation reactions between the anode and cathode produce a measurable current. Bacteria that are found in sludge can be used to produce electrons in a voltaic cell, but optimizing conditions for harnessing the energy is crucial to making a MFC efficient. Research has shown that the ratios of …


Non-Cytotoxic Antibacterial Silver–Coumarin Complex Doped Sol–Gel Coatings, Swarna Jaiswal, Kunal Bhattacharya, Maeve Sullivan, Maureen Walsh, Bernadette Creaven, Fathima Laffir, Brendan Duffy, Patrick Mchale Jan 2013

Non-Cytotoxic Antibacterial Silver–Coumarin Complex Doped Sol–Gel Coatings, Swarna Jaiswal, Kunal Bhattacharya, Maeve Sullivan, Maureen Walsh, Bernadette Creaven, Fathima Laffir, Brendan Duffy, Patrick Mchale

Articles

Microbial colonisation on clinical and industrial surfaces is currently of global concern and silane based sol–gel coatings are being proposed as potential solutions. Sol–gels are chemically inert, stable and homogeneous and can be designed to act as a reservoir for releasing antimicrobial agents over extended time periods. In the present study, silver nitrate (AgN) and a series of silver coumarin complexes based on coumarin-3-carboxylatosilver (AgC) and it is 6,7 and 8 hydroxylated analogues (Ag6, Ag7, Ag8) were incorporated into sol–gel coatings. The comparative antibacterial activity of the coatings was determined against meticillin resistant Staphylococcus aureus (MRSA) and multidrug resistance Enterobacter …


Candida Albicans Induces Arginine Biosynthetic Genes In Response To Host-Derived Reactive Oxygen Species, Claudia Jimenez-Lopez, John R. Collette, Kimberly M. Brothers, Kelly M. Shepardson, Robert A. Kramer Jan 2013

Candida Albicans Induces Arginine Biosynthetic Genes In Response To Host-Derived Reactive Oxygen Species, Claudia Jimenez-Lopez, John R. Collette, Kimberly M. Brothers, Kelly M. Shepardson, Robert A. Kramer

Dartmouth Scholarship

The interaction of Candida albicans with phagocytes of the host's innate immune system is highly dynamic, and its outcome directly impacts the progression of infection. While the switch to hyphal growth within the macrophage is the most obvious physiological response, much of the genetic response reflects nutrient starvation: translational repression and induction of alternative carbon metabolism. Changes in amino acid metabolism are not seen, with the striking exception of arginine biosynthesis, which is upregulated in its entirety during coculture with macrophages. Using single-cell reporters, we showed here that arginine biosynthetic genes are induced specifically in phagocytosed cells. This induction is …


Plant-Mediated Effects On Microbial Diversity In Mesocosms Of An Oligotrophic Bog, Karl J. Romanowicz Iv Jan 2013

Plant-Mediated Effects On Microbial Diversity In Mesocosms Of An Oligotrophic Bog, Karl J. Romanowicz Iv

Dissertations, Master's Theses and Master's Reports - Open

Globally, peatlands occupy a small portion of terrestrial land area but contain up to one-third of all soil organic carbon. This carbon pool is vulnerable to increased decomposition under projected climate change scenarios but little is known about how plant functional groups will influence microbial communities responsible for regulating carbon cycling processes. Here we examined initial shifts in microbial community structure within two sampling depths under plant functional group manipulations in mesocosms of an oligotrophic bog. Microbial community composition for bacteria and archaea was characterized using targeted 16S rRNA Illumina gene sequencing. We found statistically distinct spatial patterns between the …


Bacteriostatic Effects Of Sucralose On Environmental Bacteria, Arthur Phillip Omran Jr. Jan 2013

Bacteriostatic Effects Of Sucralose On Environmental Bacteria, Arthur Phillip Omran Jr.

UNF Graduate Theses and Dissertations

Sucralose is a zero calorie sweetener developed and manufactured by Tate and Lyle Sweetener Company in the 1980’s. They sell the sweetener compounded with maltodextrin and dextrose under the brand name Splenda®. Sucralose was developed as a low cost artificial sweetener that is non-metabolizable in humans and can withstand changes in pH and temperature. It is not degraded by the waste water treatment process. Since the molecule can withstand heat, acidification and microbial degradation it is accumulating in the environment, and has been found in waste water, estuaries, rivers and the Gulf Stream. The highest concentration of environmental sucralose detected …


Going Beyond Phosphorylation: Acetylphosphate-Mediated Ran Polymerase Acetylation And Caper Phosphorylation Co-Regulate Transcription Of Escherichia Coli Stress-Responsive Gene Cpxp, Bruno P. Lima Jan 2013

Going Beyond Phosphorylation: Acetylphosphate-Mediated Ran Polymerase Acetylation And Caper Phosphorylation Co-Regulate Transcription Of Escherichia Coli Stress-Responsive Gene Cpxp, Bruno P. Lima

Dissertations

The ability of bacteria to sense and adapt to environmental changes has al-lowed these organisms to thrive in all parts of the globe and to establish many complex interactions with the environments they live as well as other members of these environments. Crucial to monitoring extracellular conditions is a group of signaling pathways known as two-component signal transduction system (2CST). These systems relay information from the extracellular environment to the interior of the cell via a transfer of phosphoryl groups from the sensory protein know as sensor kinase (SK) to the output protein known as response regulator (RR).

In addition …


Identifying And Characterizing The Degradative Pathway Of The Retroviral Restriction Factor Rhtrim5Α, Rachel Nelson Jan 2013

Identifying And Characterizing The Degradative Pathway Of The Retroviral Restriction Factor Rhtrim5Α, Rachel Nelson

Master's Theses

Human immunodeficiency virus 1 (HIV-1) is a lentivirus that progresses to acquired immunodeficiency syndrome (AIDS). The protein TRIM5alpha from rhesus macaques (rhTRIM5alpha) restricts HIV-1 by blocking infection after entry of the virion into cells. Treatment of rhTRIM5alpha expressing cells with inhibitors to a cellular degradation pathway, the proteasome, partially relieves restriction but does not inhibit rhTRIM5alpha protein turnover. The role of a second degradation pathway, the autophagy-lysosomal pathway, in TRIM5alpha mediated restriction has not been explored.

In the present study, we demonstrate that rhTRIM5alpha is degraded by chaperone mediated autophagy (CMA). Inhibition of CMA alters rhTRIM5alpha localization and turnover, while …


Exosomes: Antiviral Agents In The Human Lung, Jennifer Alexandra Novak Jan 2013

Exosomes: Antiviral Agents In The Human Lung, Jennifer Alexandra Novak

Master's Theses

Hundreds of interferon effectors comprise the immediate host response to virus infection. One family of interferon stimulated genes is the IFITM (Interferon-Induced Transmembrane) proteins. IFITM3, in particular, has been shown to block virus cell entry of Influenza A Virus, SARS Coronavirus, and West Nile Virus, among others. IFITM3 has also been identified as an essential factor for host protection against Influenza A Virus in mice and humans. However, the mechanism by which IFITM3 functions remains unclear.

IFITM3 may function both intracellularly and extracellularly to block virus infection in the human lung. The extracellular milieu contains microscopic vesicles termed exosomes which …


Assessing The Effects Of Titanium Dioxide Nanoparticles On Microbial Communities In Stream Sediment Using Artificial Streams And High Throughput Screening, Alexandra Ozaki Jan 2013

Assessing The Effects Of Titanium Dioxide Nanoparticles On Microbial Communities In Stream Sediment Using Artificial Streams And High Throughput Screening, Alexandra Ozaki

Master's Theses

Nano-titanium dioxide (nano-TiO2) is an engineered nanomaterial used in a wide array of commercial products. The production and use of large amounts of nano-TiO2 is resulting in the unintended release to the environment. Nano-TiO2 is known to be cytotoxic due primarily to its ability to generate reactive oxygen species, and negative impacts on a variety of organisms have been demonstrated, but the effects of nano-TiO2 on complex microbial communities under ecologically relevant conditions have rarely been tested. We conducted a controlled manipulative experiment using recirculating model streams dosed with a one-time amendment of 1mg L-1 nano-TiO2 (specifically P25). Within one …


Antibodies To Inhibit Clostridium Difficile Adhesion To Human Gut Epithelial Cell Line, Wonbeom Paik Jan 2013

Antibodies To Inhibit Clostridium Difficile Adhesion To Human Gut Epithelial Cell Line, Wonbeom Paik

Master's Theses

Clostridium difficile infection (CDI) is a major hospital-acquired diarrhea that can cause life-threatening complications such as pseudomembranous colitis. CDI is caused by colonization of host with C. difficile, a Gram positive, anaerobic bacterium known to produce toxins that cause disease. Normally, the gut microbiota protects the host from CDI, but disruption of the microbial composition through antibiotic treatment can leave one vulnerable for CDI. To date, no vaccines for preventing CDI are available.

In this study, the potential of antibodies directed against specific surface molecules of C. difficile to block bacterial adherence to host gut epithelial cells was studied, in …


The Isolation And Characterisation Of Acientobacter Baumannii Bacteriophage, Mohamed Farag M. Elbreki Jan 2013

The Isolation And Characterisation Of Acientobacter Baumannii Bacteriophage, Mohamed Farag M. Elbreki

Theses

Acinetobacter baumannii is a pathogen, which has an increasing prevalence of multidrug resistance. It exists widely in natural environments, and frequently in health-care settings where it has proven difficult to eradicate using antibiotic therapy. A possible alternative to conventional antibiotics is the use of bacteriophages (phages) as antibacterials. In this project, extensive screening of environmental samples such as soils, sewage and waters was undertaken to identify suitable phages. Three phages were successfully isolated from municipal waste in the Cork area. These were subsequently characterized in detail and examined by electron microscopy, which showed that they were all of the Myoviridae …


Functional Characterization Of The Cholera Toxin Promoter Of Vibrio Cholerae, Jennifer Dittmer Jan 2013

Functional Characterization Of The Cholera Toxin Promoter Of Vibrio Cholerae, Jennifer Dittmer

Wayne State University Dissertations

Vibrio cholerae is the bacterium responsible for the severe diarrheal disease cholera. The disease is directly caused by cholera toxin, which is secreted by the bacterium in the upper small intestinal lumen during the course of infection. Expression of cholera toxin, along with other virulence genes, is activated by the positive transcriptional regulator, ToxT. ToxT binds to DNA sequences known as toxboxes that are found within promoters of virulence genes and subsequently ToxT activates transcription. However, the toxboxes have not been previously characterized in arguably the most important virulence promoter in V. cholerae, the cholera toxin promoter (PctxAB). …


Clinicopathological Spectrum Of Ovarian Sex Cord-Stromal Tumors; 20years' Retrospective Study In A Developing Country, Saroona Haroon, Aleena Zia, Romana Idrees, Aisha Memon, Saira Fatima, Naila Kayani Jan 2013

Clinicopathological Spectrum Of Ovarian Sex Cord-Stromal Tumors; 20years' Retrospective Study In A Developing Country, Saroona Haroon, Aleena Zia, Romana Idrees, Aisha Memon, Saira Fatima, Naila Kayani

Department of Pathology and Laboratory Medicine

Background:
Ovarian sex cord stromal tumors are rare neoplasms as compared to epithelial tumors. No large study has been done in Pakistan to find out the frequencies of various sex cord stromal tumors and their clinicopathological behavior in our region. The purpose of our study was to determine the various histological patterns and clinical features of ovarian sex cord stromal tumors along with follow-up in our set-up.
Methods:
It is a retrospective observational study. The study was conducted in section of Histopathology, Aga Khan University Hospital, Karachi, Pakistan. All reported cases of sex cord stromal tumors of ovary during 1992 …


Genetic Diversity Of Plasmodium Vivax Clinical Isolates From Southern Pakistan Using Pvcsp And Pvmsp1 Genetic Markers, Afsheen Raza, Najia K. Ghanchi, Ali M. Thaver, Sana Jafri, Mohammad A. Beg Jan 2013

Genetic Diversity Of Plasmodium Vivax Clinical Isolates From Southern Pakistan Using Pvcsp And Pvmsp1 Genetic Markers, Afsheen Raza, Najia K. Ghanchi, Ali M. Thaver, Sana Jafri, Mohammad A. Beg

Department of Pathology and Laboratory Medicine

Background:
Plasmodium vivax is the prevalent malarial species accounting for 70% of malaria burden in Pakistan; however, there is no baseline data on the circulating genotypes. Studies have shown that polymorphic loci of gene encoding antigens pvcsp and pvmsp1 can be used reliably for conducting molecular epidemiological studies. Therefore, this study aimed to bridge the existing knowledge gap on population structure on P. vivax from Pakistan using these two polymorphic genes.
Methods:
During the period January 2008 to May 2009, a total of 250 blood samples were collected from patients tested slide positive for P. vivax, at the Aga Khan …


Identification Of Non-Tuberculous Mycobacteria Isolated From Clinical Specimens At A Tertiary Care Hospital: A Cross-Sectional Study, Imran Ahmed, Kauser Jabeen, Rumina Hasan Jan 2013

Identification Of Non-Tuberculous Mycobacteria Isolated From Clinical Specimens At A Tertiary Care Hospital: A Cross-Sectional Study, Imran Ahmed, Kauser Jabeen, Rumina Hasan

Department of Pathology and Laboratory Medicine

Background:
Non-tuberculous mycobacteria (NTM) are opportunistic pathogens in immuno-compromised patients. They are also increasingly recognized as pathogens in immuno-competent individuals. Globally, an increase in NTM isolation is being reported with a varied geographic prevalence of different species around the world. There is lack of data on species distribution of these organisms from Pakistan. Treatment options differ according to the species isolated and its susceptibility profile. Knowledge of local species variation would help targeted therapy. This study was performed to determine frequencies of different NTM species isolated from various clinical specimens submitted at a tertiary care hospital laboratory.
Methods:
NTM isolated …