Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Genetics

Microbiology

Institution
Publication Year
Publication
Publication Type
File Type

Articles 1 - 30 of 105

Full-Text Articles in Life Sciences

9th Annual Postdoctoral Science Symposium, University Of Texas Md Anderson Cancer Center Postdoctoral Association Sep 2019

9th Annual Postdoctoral Science Symposium, University Of Texas Md Anderson Cancer Center Postdoctoral Association

MD Anderson Cancer Center Postdoctoral Association Annual Postdoctoral Science Symposium Abstracts

The mission of the Annual Postdoctoral Science Symposium (APSS) is to provide a platform for talented postdoctoral fellows throughout the Texas Medical Center to present their work to a wider audience. The MD Anderson Postdoctoral Association convened its inaugural Annual Postdoctoral Science Symposium (APSS) on August 4, 2011.

The APSS provides a professional venue for postdoctoral scientists to develop, clarify, and refine their research as a result of formal reviews and critiques of faculty and other postdoctoral scientists. Additionally, attendees discuss current research on a broad range of subjects while promoting academic interactions and enrichment and developing new collaborations.


Common Variants In The Glycerol Kinase Gene Reduce Tuberculosis Drug Efficacy, Michelle M. Bellerose, Seung-Hun Baek, Chuan-Chin Huang, Caitlin E. Moss, Eun-Ik Koh, Megan K. Proulx, Clare M. Smith, Richard E. Baker, Jong Seok Lee, Seokyong Eum, Sung Jae Shin, Sang-Nae Cho, Megan Murray, Christopher M. Sassetti Jul 2019

Common Variants In The Glycerol Kinase Gene Reduce Tuberculosis Drug Efficacy, Michelle M. Bellerose, Seung-Hun Baek, Chuan-Chin Huang, Caitlin E. Moss, Eun-Ik Koh, Megan K. Proulx, Clare M. Smith, Richard E. Baker, Jong Seok Lee, Seokyong Eum, Sung Jae Shin, Sang-Nae Cho, Megan Murray, Christopher M. Sassetti

Open Access Articles

Despite the administration of multiple drugs that are highly effective in vitro, tuberculosis (TB) treatment requires prolonged drug administration and is confounded by the emergence of drug-resistant strains. To understand the mechanisms that limit antibiotic efficacy, we performed a comprehensive genetic study to identify Mycobacterium tuberculosis genes that alter the rate of bacterial clearance in drug-treated mice. Several functionally distinct bacterial genes were found to alter bacterial clearance, and prominent among these was the glpK gene that encodes the glycerol-3-kinase enzyme that is necessary for glycerol catabolism. Growth on glycerol generally increased the sensitivity of M. tuberculosis to antibiotics in ...


Effects Of Evolution On Laboratory Sublines Of Myxococcus Xanthus Dk1622, Mackenzie Ryan, Francesca Scribano, Kimberly Murphy Oct 2018

Effects Of Evolution On Laboratory Sublines Of Myxococcus Xanthus Dk1622, Mackenzie Ryan, Francesca Scribano, Kimberly Murphy

Celebration of Learning

Microbes have served as effective models for studying evolution because of their ability to be easily replicated, stored, and manipulated. Myxococcus xanthus is a soil bacterium that has served as a model organism in many laboratories. The unique social and motile behaviors exhibited by this bacterium make it ideal for phenotypic assays. A wild-type strain of M. xanthus, DK1622, has been distributed to laboratories across the United States and therefore we now have DK1622 sublines. The genomes of a number of these sublines have been sequenced and their social and motile phenotypes have been analyzed. When nine of these sublines ...


Orbit: A New Paradigm For Genetic Engineering Of Mycobacterial Chromosomes, Kenan C. Murphy, Samantha J. Nelson, Subhalaxmi Nambi, Kadamba Papavinasasundaram, Christina E. Baer, Christopher M. Sassetti Jan 2018

Orbit: A New Paradigm For Genetic Engineering Of Mycobacterial Chromosomes, Kenan C. Murphy, Samantha J. Nelson, Subhalaxmi Nambi, Kadamba Papavinasasundaram, Christina E. Baer, Christopher M. Sassetti

University of Massachusetts Medical School Faculty Publications

Current methods for genome engineering in mycobacteria rely on relatively inefficient recombination systems that require the laborious construction of a long double-stranded DNA substrate for each desired modification. We combined two efficient recombination systems to produce a versatile method for high-throughput chromosomal engineering that obviates the need for the preparation of double-stranded DNA recombination substrates. A synthetic targeting oligonucleotide is incorporated into the chromosome via homologous recombination mediated by the phage Che9c RecT annelase. This oligo contains a site-specific recombination site for the directional Bxb1 integrase (Int), which allows the simultaneous integration of a payload plasmid that contains a cognate ...


Effect Of Variation In An Essential Folding Element On The Cobalamin Riboswitch, Marcus Urquijo Jan 2018

Effect Of Variation In An Essential Folding Element On The Cobalamin Riboswitch, Marcus Urquijo

Undergraduate Honors Theses

Riboswitches are RNA-based genetic regulatory elements that control gene expression without the need for protein cofactors. These RNA motifs are found within the 5’ untranslated regions of mRNA and promote genetic regulation by altering the structure of RNA through binding small molecule effector ligands that cause conformational changes that repress or activate translation/transcription. The env8 cobalamin riboswitch binds cyanocobalamin (CNCbl) to repress gene expression of the downstream mRNA. It accomplishes this through an interplay of two separate domains; an aptamer domain which binds the effector ligand and a regulatory domain which contains the genetic switch. Within the aptamer domain ...


Genetic Diversity Of Mycobacteriophages And The Unique Abilities Of Cluster K, Shea A. Morris Jun 2017

Genetic Diversity Of Mycobacteriophages And The Unique Abilities Of Cluster K, Shea A. Morris

The Corinthian

Mycobacteriophage are a diverse set of viruses that infect a broad host range of mycobacterium. Genome analysis of this phage group reveals its diversity and provides evidence that they have experienced substantial horizontal gene transfer Collectively they have a large range of host bacteria they can infect, although each viral type may have a limited host range. However, this range is easily expanded and constantly changing in nature by mutation within and between virus types. These phages can lytically destroy their host mycobacteria, and it is this viral ability that have many mycobacteriophage researchers excited about the potential that phage ...


Antimalarial Exoerythrocytic Stage Drug Discovery And Resistance Studies, Lynn Dong Blake Jul 2016

Antimalarial Exoerythrocytic Stage Drug Discovery And Resistance Studies, Lynn Dong Blake

Graduate Theses and Dissertations

Malaria is a devastating global health issue that affects approximately 200 million people yearly and over half a million deaths are caused by this parasitic protozoan disease. Most commercially available drugs only target the blood stage form of the parasite, but the only way to ensure proper elimination is to treat the exoerythrocytic stages of the parasite development cycle. There is a demand for the discovery of new liver stage antimalarial compounds as there are only two current FDA approved drugs for the treatment of liver stage parasites, one of which fails to eliminate dormant forms and the other inducing ...


Characterization Of The Marine Sponge Amphimedon Compressa Microbiome Across A Spatial Gradient, Renee Michelle Potens May 2016

Characterization Of The Marine Sponge Amphimedon Compressa Microbiome Across A Spatial Gradient, Renee Michelle Potens

HCNSO Student Theses and Dissertations

Diverse and ecologically important microbial communities (microbiomes) are symbiotic within marine sponges. In this study, the microbiome of Amphimedon compressa from three sample locations (Broward and Dade Counties, Southeast Florida, USA and the Southern Caribbean, Bocas del Toro, Panama) is characterized using 16S rRNA Illumina sequencing. The predominant taxa are Proteobacteria and Cyanobacteria, as expected for Low Microbial Abundance sponges, accounting for over 53% of the total microbiome community. The numbers of Operational Taxonomic Units (OTUs) decrease from Broward County (2,900) to Dade County (2,300) and then Bocas del Toro (1,200). The correlates to a decreasing north-south ...


Role Of The Dna Sensor Sting In Protection From Lethal Infection Following Corneal And Intracerebral Challenge With Herpes Simplex Virus 1, Zachary M. Parker, Aisling A. Murphy, David. A. Leib Aug 2015

Role Of The Dna Sensor Sting In Protection From Lethal Infection Following Corneal And Intracerebral Challenge With Herpes Simplex Virus 1, Zachary M. Parker, Aisling A. Murphy, David. A. Leib

Open Dartmouth: Faculty Open Access Scholarship

STING is a protein in the cytosolic DNA and cyclic dinucleotide sensor pathway that is critical for the initiation of innate responses to infection by various pathogens. Consistent with this, herpes simplex virus 1 (HSV-1) causes invariable and rapid lethality in STING-deficient (STING(-/-)) mice following intravenous (i.v.) infection. In this study, using real-time bioluminescence imaging and virological assays, as expected, we demonstrated that STING(-/-) mice support greater replication and spread in ocular tissues and the nervous system. In contrast, they did not succumb to challenge via the corneal route even with high titers of a virus that was routinely ...


Selective Involvement Of The Checkpoint Regulator Vista In Suppression Of B-Cell, But Not T-Cell, Responsiveness By Monocytic Myeloid-Derived Suppressor Cells From Mice Infected With An Immunodeficiency-Causing Retrovirus, Kathy A. Green, Li Wang, Randolph J. Noelle, William R. Green Jul 2015

Selective Involvement Of The Checkpoint Regulator Vista In Suppression Of B-Cell, But Not T-Cell, Responsiveness By Monocytic Myeloid-Derived Suppressor Cells From Mice Infected With An Immunodeficiency-Causing Retrovirus, Kathy A. Green, Li Wang, Randolph J. Noelle, William R. Green

Open Dartmouth: Faculty Open Access Scholarship

Inhibition of T-cell responses in tumor microenvironments by myeloid-derived suppressor cells (MDSCs) is widely accepted. We demonstrated augmentation of monocytic MDSCs whose suppression of not only T-cell, but also B-cell, responsiveness paralleled the immunodeficiency during LP-BM5 retrovirus infection. MDSCs inhibited T cells by inducible nitric oxide synthase (iNOS)/nitric oxide (NO), but uniquely, inhibition of B cells was ~50% dependent each on iNOS/NO and the MDSC-expressed negative-checkpoint regulator VISTA. Blockade with a combination of iNOS/NO and VISTA caused additive or synergistic abrogation of MDSC-mediated suppression of B-cell responsiveness.


Deletion Of Nfnab In Thermoanaerobacterium Saccharolyticum And Its Effect On Metabolism, Jonathan Lo, Tianyong Zheng, Daniel G. Olson, Natalie Ruppertsberger, Shital Tripathi, Adam Guss, Lee Lynd Jun 2015

Deletion Of Nfnab In Thermoanaerobacterium Saccharolyticum And Its Effect On Metabolism, Jonathan Lo, Tianyong Zheng, Daniel G. Olson, Natalie Ruppertsberger, Shital Tripathi, Adam Guss, Lee Lynd

Open Dartmouth: Faculty Open Access Scholarship

NfnAB catalyzes the reversible transfer of electrons from reduced ferredoxin and NADH to 2 NADP+. The NfnAB complex has been hypothesized to be the main enzyme for ferredoxin oxidization in strains of Thermoanaerobacterium saccharolyticum engineered for increased ethanol production. NfnAB complex activity was detectable in crude cell extracts of T. saccharolyticum. Activity was also detected using activity staining of native PAGE gels. The nfnAB gene was deleted in different strains of T. saccharolyticum to determine its effect on end product formation. In wild-type T. saccharolyticum, deletion of nfnAB resulted in a 46% increase in H2 formation but otherwise little ...


Cofactor Specificity Of The Bifunctional Alcohol And Aldehyde Dehydrogenase (Adhe) In Wild-Type And Mutant Clostridium Thermocellum And Thermoanaerobacterium Saccharolyticum, Tianyong Zheng, Daniel G. Olson, Liang Tian, Yannick J. Bomble, Michael Himmel, Jonathan Lo, Shuen Hon, A. Joe Shaw, Johannes P. Van Dijken, Lee Lynd May 2015

Cofactor Specificity Of The Bifunctional Alcohol And Aldehyde Dehydrogenase (Adhe) In Wild-Type And Mutant Clostridium Thermocellum And Thermoanaerobacterium Saccharolyticum, Tianyong Zheng, Daniel G. Olson, Liang Tian, Yannick J. Bomble, Michael Himmel, Jonathan Lo, Shuen Hon, A. Joe Shaw, Johannes P. Van Dijken, Lee Lynd

Open Dartmouth: Faculty Open Access Scholarship

Clostridium thermocellum and Thermoanaerobacterium saccharolyticum are thermophilic bacteria that have been engineered to produce ethanol from the cellulose and hemicellulose fractions of biomass, respectively. Although engineered strains of T. saccharolyticum produce ethanol with a yield of 90% of the theoretical maximum, engineered strains of C. thermocellum produce ethanol at lower yields (∼50% of the theoretical maximum). In the course of engineering these strains, a number of mutations have been discovered in their adhE genes, which encode both alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) enzymes. To understand the effects of these mutations, the adhE genes from six strains of C ...


Functional Analysis Of Rev Binding Region 2, A Structural Element Of The Eiav Rev Responsive Element, Jerald Rudy Chavez Jan 2015

Functional Analysis Of Rev Binding Region 2, A Structural Element Of The Eiav Rev Responsive Element, Jerald Rudy Chavez

Graduate Theses and Dissertations

Lentiviruses translate their structural and enzymatic proteins from unspliced and singly spliced viral mRNAs (vRNAs). Export to the cytoplasm of the incompletely spliced transcripts is mediated by the viral Rev protein. Rev binds to a highly structured region of the unspliced/singly spliced RNA, termed the Rev responsive element (RRE), multimerizes, and tethers the RNA to cellular export factors to cross the nuclear membrane. While Rev-RRE mediated nuclear export is well studied in human immunodeficiency virus type 1 (HIV-1), the interaction between the equine infectious anemia virus (EIAV) Rev and the RRE is less well studied. Chemical footprinting analysis indicates ...


Nucleic Acid Detection Techniques For Adventitious Agent Testing, Kaitlin Elizabeth Brien Jan 2015

Nucleic Acid Detection Techniques For Adventitious Agent Testing, Kaitlin Elizabeth Brien

Graduate Theses and Dissertations

The availability of safe and effective animal vaccines is critical for the prevention of animal disease. Adventitious agent testing is done on master seed viruses prior to vaccine licensure to ensure that no biological contaminants were introduced during manufacture. Traditional adventitious agent testing is performed using a variety of cell culture lines and a panel of polymerase chain reaction tests. The purpose of this research was to determine if new technologies like DNA microarray and next-generation sequencing (NGS) could be of any benefit for adventitious agent testing. A literature review describes the state of the field and the challenges that ...


Elucidation Of A Bacteriophytochrome-Regulated Signal Transduction Pathway In Pseudomonas Syringae That Contributes To Leaf Colonization, Virulence, And Swarming Motility, Regina S. Mcgrane Jan 2015

Elucidation Of A Bacteriophytochrome-Regulated Signal Transduction Pathway In Pseudomonas Syringae That Contributes To Leaf Colonization, Virulence, And Swarming Motility, Regina S. Mcgrane

Graduate Theses and Dissertations

Plant-associated bacteria encounter a range of stressful environmental conditions when colonizing leaf surfaces. To adapt to these harsh conditions bacteria sense and respond to environmental signals. Within the last two decades, photoreceptors that respond to specific wavelengths of light through associated chromophores have been discovered with increasing frequency in non-photosynthetic bacteria, including those associated with plants. Their presence suggests that fluctuations in light may serve as a cue to regulate bacterial adaptations. The foliar plant pathogen Pseudomonas syringae is unusual among heterotrophic bacteria because it encodes three photoreceptors, two red- and/or far-red light-sensing bacteriophytochromes and a blue light-sensing LOV ...


Development Of Gold Nanoparticle-Based Antigen Delivery Platform For Vaccines Against Hiv-1, Feng Lin Jan 2015

Development Of Gold Nanoparticle-Based Antigen Delivery Platform For Vaccines Against Hiv-1, Feng Lin

Graduate Theses and Dissertations

As one of the world’s most devastating viruses, HIV-1 has killed more than 39 million people, and around two million cases of newly infected individuals are recorded every year. However, no effective vaccine has been developed to stop this pandemic since its onset in the 1980s. Since vaccine development is moving slowly, delivery platforms as an essential element to enhance both the efficiency and efficacy of vaccines have drawn increased attention. Gold nanoparticles (GNPs) as a novel delivery platform has been studied in drug and vaccine delivery. My research goal is to apply this delivery platform in the AIDS ...


Mcl1 Enhances The Survival Of Cd8+ Memory T Cells After Viral Infection, Jingang Gui, Zhuting Hu, Ching-Yi Tsai, Tian Ma, Yan Song, Amanda Morales, Li-Hao Huang, Ethan Dmitrovsky, Ruth Craig, Edward Usherwood Jan 2015

Mcl1 Enhances The Survival Of Cd8+ Memory T Cells After Viral Infection, Jingang Gui, Zhuting Hu, Ching-Yi Tsai, Tian Ma, Yan Song, Amanda Morales, Li-Hao Huang, Ethan Dmitrovsky, Ruth Craig, Edward Usherwood

Open Dartmouth: Faculty Open Access Scholarship

Viral infection results in the generation of massive numbers of activated effector CD8+ T cells that recognize viral components. Most of these are short-lived effector T cells (SLECs) that die after clearance of the virus. However, a small proportion of this population survives and forms antigen-specific memory precursor effector cells (MPECs), which ultimately develop into memory cells. These can participate in a recall response upon reexposure to antigen even at protracted times postinfection. Here, antiapoptotic myeloid cell leukemia 1 (MCL1) was found to prolong survival upon T cell stimulation, and mice expressing human MCL1 as a transgene exhibited a skewing ...


Host Species Restriction Of Middle East Respiratory Syndrome Coronavirus Through Its Receptor, Dipeptidyl Peptidase 4, Neeltje Van Doremalen, Kerri L. Miazgowicz, Shauna Milne-Price, Trenton Bushmaker, Shelly Robertson, Dana Scott, Joerg Kinne, Jason S. Mclellan Jun 2014

Host Species Restriction Of Middle East Respiratory Syndrome Coronavirus Through Its Receptor, Dipeptidyl Peptidase 4, Neeltje Van Doremalen, Kerri L. Miazgowicz, Shauna Milne-Price, Trenton Bushmaker, Shelly Robertson, Dana Scott, Joerg Kinne, Jason S. Mclellan

Open Dartmouth: Faculty Open Access Scholarship

Middle East respiratory syndrome coronavirus (MERS-CoV) emerged in 2012. Recently, the MERS-CoV receptor dipeptidyl peptidase 4 (DPP4) was identified and the specific interaction of the receptor-binding domain (RBD) of MERS-CoV spike protein and DPP4 was determined by crystallography. Animal studies identified rhesus macaques but not hamsters, ferrets, or mice to be susceptible for MERS-CoV. Here, we investigated the role of DPP4 in this observed species tropism. Cell lines of human and nonhuman primate origin were permissive of MERS-CoV, whereas hamster, ferret, or mouse cell lines were not, despite the presence of DPP4. Expression of human DPP4 in nonsusceptible BHK and ...


Structural Features Of The Pseudomonas Fluorescens Biofilm Adhesin Lapa Required For Lapg-Dependent Cleavage, Biofilm Formation, And Cell Surface Localization, Chelsea D. Boyd, T. Jarrod Smith, Sofiane El-Kirat-Chatel, Peter D. Newell, Yves F. Dufrêne, George A. O'Toole May 2014

Structural Features Of The Pseudomonas Fluorescens Biofilm Adhesin Lapa Required For Lapg-Dependent Cleavage, Biofilm Formation, And Cell Surface Localization, Chelsea D. Boyd, T. Jarrod Smith, Sofiane El-Kirat-Chatel, Peter D. Newell, Yves F. Dufrêne, George A. O'Toole

Open Dartmouth: Faculty Open Access Scholarship

The localization of the LapA protein to the cell surface is a key step required by Pseudomonas fluorescens Pf0-1 to irreversibly attach to a surface and form a biofilm. LapA is a member of a diverse family of predicted bacterial adhesins, and although lacking a high degree of sequence similarity, family members do share common predicted domains. Here, using mutational analysis, we determine the significance of each domain feature of LapA in relation to its export and localization to the cell surface and function in biofilm formation. Our previous work showed that the N terminus of LapA is required for ...


Deletion Mutant Library For Investigation Of Functional Outputs Of Cyclic Diguanylate Metabolism In Pseudomonas Aeruginosa Pa14, Dae-Gon Ha, Megan E. Richman, George A. O'Toole Mar 2014

Deletion Mutant Library For Investigation Of Functional Outputs Of Cyclic Diguanylate Metabolism In Pseudomonas Aeruginosa Pa14, Dae-Gon Ha, Megan E. Richman, George A. O'Toole

Open Dartmouth: Faculty Open Access Scholarship

We constructed a library of in-frame deletion mutants targeting each gene in Pseudomonas aeruginosa PA14 predicted to participate in cyclic di-GMP (c-di-GMP) metabolism (biosynthesis or degradation) to provide a toolkit to assist investigators studying c-di-GMP-mediated regulation by this microbe. We present phenotypic assessments of each mutant, including biofilm formation, exopolysaccharide (EPS) production, swimming motility, swarming motility, and twitch motility, as a means to initially characterize these mutants and to demonstrate the potential utility of this library.


Gene And Protein Sequence Optimization For High-Level Production Of Fully Active And Aglycosylated Lysostaphin In Pichia Pastoris, Hongliang Zhao, Kristina Blazanovic, Yoonjoo Choi, Chris Bailey-Kellogg, Karl E. Griswold Feb 2014

Gene And Protein Sequence Optimization For High-Level Production Of Fully Active And Aglycosylated Lysostaphin In Pichia Pastoris, Hongliang Zhao, Kristina Blazanovic, Yoonjoo Choi, Chris Bailey-Kellogg, Karl E. Griswold

Open Dartmouth: Faculty Open Access Scholarship

Lysostaphin represents a promising therapeutic agent for the treatment of staphylococcal infections, in particular those of methicillin-resistant Staphylococcus aureus (MRSA). However, conventional expression systems for the enzyme suffer from various limitations, and there remains a need for an efficient and cost-effective production process to facilitate clinical translation and the development of nonmedical applications. While Pichia pastoris is widely used for high-level production of recombinant proteins, there are two major barriers to the production of lysostaphin in this industrially relevant host: lack of expression from the wild-type lysostaphin gene and aberrant glycosylation of the wild-type protein sequence. The first barrier can ...


Molecular Effects Of Mammalian Orthoreovirus (Mrv) Infection On Hypoxic Prostate Tumor Cells, Pooja Gupta Jan 2014

Molecular Effects Of Mammalian Orthoreovirus (Mrv) Infection On Hypoxic Prostate Tumor Cells, Pooja Gupta

Graduate Theses and Dissertations

Mammalian Orthoreovirus (MRV), a double-stranded RNA virus, is a potent oncolytic virus, which specifically replicates in tumor cells and consequently kills them. Hypoxia, a condition of low oxygen, is a characteristic feature of most solid tumors and develops due to tumor cells outgrowing their blood supply. Hypoxic cell survival is driven by the transcriptional activity of hypoxia inducible factor-1 (HIF-1). We examined the ability of MRV to infect hypoxic prostate tumor cells and found that not only did it successfully translate proteins and replicate in hypoxic prostate tumor cells, it also induced apoptosis. In addition, MRV induced downregulation of the ...


Computational And Experimental Analysis Of Retroviral Rev-Like Proteins, Chijioke Umunnakwe Jan 2014

Computational And Experimental Analysis Of Retroviral Rev-Like Proteins, Chijioke Umunnakwe

Graduate Theses and Dissertations

The discovery of retroviral reverse transcriptase by Howard Temin and David Baltimore in 1970 revolutionized the field of molecular biology. Retroviruses have since become an invaluable research tool. At the same time, retroviruses continue to pose significant public health risk in terms of being causative agents for particularly devastating diseases like AIDS. Understanding the molecular mechanisms underlying essential functions in retroviruses is of immense interest. Rev-like proteins are essential regulatory proteins that function to mediate nuclear export of incompletely spliced mRNAs in retroviruses such as HIV-1. Following translation, HIV-1 Rev localizes to the nucleus and binds a unique sequence in ...


Function Of Class One Nonsymbiotic Plant Hemoglobins, Xiaoguang Wang Jan 2014

Function Of Class One Nonsymbiotic Plant Hemoglobins, Xiaoguang Wang

Graduate Theses and Dissertations

Plants lack a circulatory system for oxygen. Thus hypoxia and anoxia are potential problems for plants. Environmental factors like flooding can make such problems even worse. At hypoxia and anoxia conditions, both nitrogen metabolism enzymes and nonsymbiotic hemoglobins in plants are up-regulated. Meanwhile, nitrite and nitric oxide are accumulated. Two physiological roles of plant nonsymbiotic hemoglobins were proposed: 1) nitric oxide scavenging during plant hypoxia using NOD function involving ascorbate and monodehydroascorbate reductase; 2) dissimilatory nitrite reduction during plant hypoxia or anoxia cooperating with other factors (since plant hemoglobin itself cannot reduce nitrite to ammonium in vitro). This thesis includes ...


Divergent Antibody Subclass And Specificity Profiles But Not Protective Hla-B Alleles Are Associated With Variable Antibody Effector Function Among Hiv-1 Controllers, Jennifer I. Lai, Anna F. Licht, Anne-Sophie Dugast, Todd Suscovich, Ickwon Choi, Chris Bailey-Kellogg, Galit Alter, Margaret E. Ackerman Dec 2013

Divergent Antibody Subclass And Specificity Profiles But Not Protective Hla-B Alleles Are Associated With Variable Antibody Effector Function Among Hiv-1 Controllers, Jennifer I. Lai, Anna F. Licht, Anne-Sophie Dugast, Todd Suscovich, Ickwon Choi, Chris Bailey-Kellogg, Galit Alter, Margaret E. Ackerman

Open Dartmouth: Faculty Open Access Scholarship

Understanding the coordination between humoral and cellular immune responses may be the key to developing protective vaccines, and because genetic studies of long-term HIV-1 nonprogressors have associated specific HLA-B alleles with spontaneous control of viral replication, this subject group presents an opportunity to investigate relationships between arms of the adaptive immune system. Given evidence suggesting that cellular immunity may play a role in viral suppression, we sought to determine whether and how the humoral immune response might vary among controllers. Significantly, Fc-mediated antibody effector functions have likewise been associated with durable viral control. In this study, we compared the effector ...


Use Of Irf-3 And/Or Irf-7 Knockout Mice To Study Viral Pathogenesis: Lessons From A Murine Retrovirus-Induced Aids Model, Megan A. O'Connor, William R. Green Dec 2013

Use Of Irf-3 And/Or Irf-7 Knockout Mice To Study Viral Pathogenesis: Lessons From A Murine Retrovirus-Induced Aids Model, Megan A. O'Connor, William R. Green

Open Dartmouth: Faculty Open Access Scholarship

Interferon regulatory factor (IRF) regulation of the type I interferon response has not been extensively explored in murine retroviral infections. IRF-3(-/-) and select IRF-3/7(-/-) mice were resistant to LP-BM5-induced pathogenesis. However, further analyses strongly suggested that resistance could be attributed to strain 129-specific contamination of the known retrovirus resistance gene Fv1. Therefore, caution should be taken when interpreting phenotypes observed in these knockout mice, as strain 129-derived genetic polymorphisms may explain observed differences.


Role Of The Cipa Scaffoldin Protein In Cellulose Solubilization, As Determined By Targeted Gene Deletion And Complementation In Clostridium Thermocellum, Daniel G. Olson, Richard J. Giannone, Robert L. Hettich, Lee R. Lynd Nov 2013

Role Of The Cipa Scaffoldin Protein In Cellulose Solubilization, As Determined By Targeted Gene Deletion And Complementation In Clostridium Thermocellum, Daniel G. Olson, Richard J. Giannone, Robert L. Hettich, Lee R. Lynd

Open Dartmouth: Faculty Open Access Scholarship

The CipA scaffoldin protein plays a key role in the Clostridium thermocellum cellulosome. Previous studies have revealed that mutants deficient in binding or solubilizing cellulose also exhibit reduced expression of CipA. To confirm that CipA is, in fact, necessary for rapid solubilization of crystalline cellulose, the gene was deleted from the chromosome using targeted gene deletion technologies. The CipA deletion mutant exhibited a 100-fold reduction in cellulose solubilization rate, although it was eventually able to solubilize 80% of the 5 g/liter cellulose initially present. The deletion mutant was complemented by a copy of cipA expressed from a replicating plasmid ...


In Vitro Characterization Of Avian Influenza Virus Isolates With A Truncated Ns1 Gene Segment, Aaron Dick May 2013

In Vitro Characterization Of Avian Influenza Virus Isolates With A Truncated Ns1 Gene Segment, Aaron Dick

Honors Scholar Theses

Avian Influenza Virus represents a significant threat to the world poultry population, and is a potential threat to humans due to the possibility of cross-species AIV infection. Our approach is to characterize a number of avian virus populations with respect to their content of biologically active particles that include hemagglutinating particles (HAP), plaque forming particles (PFP), interferon inducing particles (IFP), interferon induction-suppressing particles (ISP), defective-interfering particles (DIP), cell-killing particles (CKP) and non-infectious cell killing particles (niCKP) using unique in vitro assays developed for avian influenza virus in the Marcus-Sekellick Laboratory. Specifically, we will use a strain of Avian influenza virus ...


Atypical Glycolysis In Clostridium Thermocellum, Jilai Zhou, Daniel G. Olson, D. Aaron Argyros, Yu Deng, Walter M. Van Gulik, Johannes P. Van Dijken, Lee R. Lynd Feb 2013

Atypical Glycolysis In Clostridium Thermocellum, Jilai Zhou, Daniel G. Olson, D. Aaron Argyros, Yu Deng, Walter M. Van Gulik, Johannes P. Van Dijken, Lee R. Lynd

Open Dartmouth: Faculty Open Access Scholarship

Cofactor specificities of glycolytic enzymes in Clostridium thermocellum were studied with cellobiose-grown cells from batch cultures. Intracellular glucose was phosphorylated by glucokinase using GTP rather than ATP. Although phosphofructokinase typically uses ATP as a phosphoryl donor, we found only pyrophosphate (PPi)-linked activity. Phosphoglycerate kinase used both GDP and ADP as phosphoryl acceptors. In agreement with the absence of a pyruvate kinase sequence in the C. thermocellum genome, no activity of this enzyme could be detected. Also, the annotated pyruvate phosphate dikinase (ppdk) is not crucial for the generation of pyruvate from phosphoenolpyruvate (PEP), as deletion of the ppdk gene ...


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

Open Dartmouth: Faculty Open Access 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 ...