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Biosynthesis And Roles Of Virulence Conferring Cell Wall Associated Dimycocerosate Esters In Mycobacterium Marinum, Poornima Mohandas 2016 Graduate Center, City University of New York

Biosynthesis And Roles Of Virulence Conferring Cell Wall Associated Dimycocerosate Esters In Mycobacterium Marinum, Poornima Mohandas

All Graduate Works by Year: Dissertations, Theses, and Capstone Projects

Mycobacterial species include a variety of obligate and opportunistic pathogens that cause several important diseases affecting mankind such as tuberculosis and leprosy. The most unique feature of these bacteria is their intricate cell wall that poses a permeability barrier to antibiotics and contributes to their pathogenicity and persistence within the host. The cell wall hosts several complex lipids such as dimycocerosate esters (DIMs), which are found in many clinically relevant pathogenic species of mycobacteria. DIMs have been implicated in the virulence of mycobacteria and play a major role in helping the bacteria evade host immune responses. It is therefore crucial ...


The Effects Of Quorum Sensing And Temperature On The Soluble Proteome Of Vibrio Salmonicida, Christopher L. Massey 2016 California Polytechnic State University, San Luis Obispo

The Effects Of Quorum Sensing And Temperature On The Soluble Proteome Of Vibrio Salmonicida, Christopher L. Massey

Master's Theses and Project Reports

Vibrio salmonicida causes cold-water vibriosis in salmon populations around the world and causes financial damage to fisheries designed to farm these salmon. Very little is known about the physiology of how V. salmonicida causes disease and measures to contain vibriosis are restricted to either vaccinating individual fish against disease or administering antibiotics when an outbreak is detected. These procedures are costly and increase the risk for selection of antibiotic-resistant V. salmonicida strains. A recent reoccurrence of outbreaks in Norwegian fisheries provided incentive to better understand the virulence mechanisms of V. salmonicida. In this thesis, a proteomic approach was used to ...


Handwashing: A Study Of The History, Methods, And Psychology Surrounding Hand Hygiene, Daniel J. Remillard 2016 Liberty University

Handwashing: A Study Of The History, Methods, And Psychology Surrounding Hand Hygiene, Daniel J. Remillard

Senior Honors Theses

This paper covers three different areas concerning handwashing. First a review of the history of handwashing is done, going from ancient times to its introduction into modern medicine via Dr. Ignaz Semmelweis. This section gives a sobering reminder not to instantly reject data that comes in conflict with prevalent thought.

Then current medical knowledge about handwashing is examined, and the conclusion reached states that handwashing is best done with non-antibacterial soap.

Finally, a review of the psychology of handwashing shows that medical professionals often tend toward neglect if unwatched and unmotivated by an outside source. However, those suffering from obsessive ...


Environmentally Driven Orchestration Of Metabolisms By Prochlorococcus Spp., Martin James Szul 2016 University of Tennessee - Knoxville

Environmentally Driven Orchestration Of Metabolisms By Prochlorococcus Spp., Martin James Szul

Doctoral Dissertations

In the oligotrophic waters of the world’s open oceans physical factors such as pH, salinity, and temperature are generally stable. The nutrient limited conditions as well as the low environmental variability endemic to these ecosystems select for specialists that gain fitness advantages through minimalism, efficiency, and thrift. These physical characteristics are thought to reduce nutrient demand while allowing for constant metabolic activity and growth, but the mechanisms that promote these fitness advantages are currently unknown. To better understand how these physiologies improve selective fitness for the dominant phytoplankton, we observed metabolic parameters under environmental conditions typical to these waters ...


Toxicity Of Engineered Nanomaterials To Plant Growth Promoting Rhizobacteria, Ricky W. Lewis 2016 University of Kentucky

Toxicity Of Engineered Nanomaterials To Plant Growth Promoting Rhizobacteria, Ricky W. Lewis

Theses and Dissertations--Plant and Soil Sciences

Engineered nanomaterials (ENMs) have become ubiquitous in consumer products and industrial applications, and consequently the environment. Much of the environmentally released ENMs are expected to enter terrestrial ecosystems via land application of nano-enriched biosolids to agricultural fields. Among the organisms most likely to encounter nano-enriched biosolids are the key soil bacteria known as plant growth promoting rhizobacteria (PGPR). I reviewed what is known concerning the toxicological effects of ENMs to PGPR and observed the need for high-throughput methods to evaluate lethal and sublethal toxic responses of aerobic microbes. I addressed this issue by developing high-throughput microplate assays which allowed me ...


Direct Visualization Of Hiv-1 Replication Intermediates Shows That Capsid And Cpsf6 Modulate Hiv-1 Intra-Nuclear Invasion And Integration, Christopher R. Chin, Jill Perreira, George Savidis, Jocelyn M. Portmann, Aaron M. Aker, Eric M. Feeley, Miles C. Smith, Abraham L. Brass 2015 University of Massachusetts Medical School

Direct Visualization Of Hiv-1 Replication Intermediates Shows That Capsid And Cpsf6 Modulate Hiv-1 Intra-Nuclear Invasion And Integration, Christopher R. Chin, Jill Perreira, George Savidis, Jocelyn M. Portmann, Aaron M. Aker, Eric M. Feeley, Miles C. Smith, Abraham L. Brass

Microbiology and Physiological Systems Publications and Presentations

Direct visualization of HIV-1 replication would improve our understanding of the viral life cycle. We adapted established technology and reagents to develop an imaging approach, ViewHIV, which allows evaluation of early HIV-1 replication intermediates, from reverse transcription to integration. These methods permit the simultaneous evaluation of both the capsid protein (CA) and viral DNA genome (vDNA) components of HIV-1 in both the cytosol and nuclei of single cells. ViewHIV is relatively rapid, uses readily available reagents in combination with standard confocal microscopy, and can be done with virtually any HIV-1 strain and permissive cell lines or primary cells. Using ViewHIV ...


Rnasek Is A V-Atpase-Associated Factor Required For Endocytosis And The Replication Of Rhinovirus, Influenza A Virus, And Dengue Virus, Jill Perreira, Aaron Aker, George Savidis, Christopher R. Chin, William M. McDougall, Jocelyn M. Portmann, Paul Meraner, Miles Smith, Motiur Rahman, Richard E. Baker, Annick Gauthier, Michael Franti, Abraham L. Brass 2015 University of Massachusetts Medical School

Rnasek Is A V-Atpase-Associated Factor Required For Endocytosis And The Replication Of Rhinovirus, Influenza A Virus, And Dengue Virus, Jill Perreira, Aaron Aker, George Savidis, Christopher R. Chin, William M. Mcdougall, Jocelyn M. Portmann, Paul Meraner, Miles Smith, Motiur Rahman, Richard E. Baker, Annick Gauthier, Michael Franti, Abraham L. Brass

Open Access Articles

Human rhinovirus (HRV) causes upper respiratory infections and asthma exacerbations. We screened multiple orthologous RNAi reagents and identified host proteins that modulate HRV replication. Here, we show that RNASEK, a transmembrane protein, was needed for the replication of HRV, influenza A virus, and dengue virus. RNASEK localizes to the cell surface and endosomal pathway and closely associates with the vacuolar ATPase (V-ATPase) proton pump. RNASEK is required for endocytosis, and its depletion produces enlarged clathrin-coated pits (CCPs) at the cell surface. These enlarged CCPs contain endocytic cargo and are bound by the scissioning GTPase, DNM2. Loss of RNASEK alters the ...


The Role Of Phosphatidylserine And Phosphatidylethanolamine In Candida Albicans Virulence, Sarah Elizabeth Davis 2015 University of Tennessee - Knoxville

The Role Of Phosphatidylserine And Phosphatidylethanolamine In Candida Albicans Virulence, Sarah Elizabeth Davis

Doctoral Dissertations

In hospitalized patients with neutropenia, Candida albicans is the fourth leading cause of systemic bloodstream infections, which have a mortality rate of approximately 30 %. The phosphatidylserine synthase enzyme of C. albicans, Cho1p, appears to be a good drug target as a mutant lacking this enzyme (the cho1Δ/Δ [null mutant]) is avirulent in animal models of Candida infections and this enzyme is not conserved in humans. We discovered that the loss of phosphatidylserine (PS) synthesis affects C. albicans' expression of the Als3p adhesin, a virulence protein, and loss of PS synthesis also compromises the cell wall, causing increased exposure ...


Secretion Of Heat-Labile Enterotoxin By Porcine-Origin Enterotoxigenic Escherichia Coli And Relation To Virulence, Prageeth R. Wijemanne 2015 University of Nebraska-Lincoln

Secretion Of Heat-Labile Enterotoxin By Porcine-Origin Enterotoxigenic Escherichia Coli And Relation To Virulence, Prageeth R. Wijemanne

Dissertations & Theses in Veterinary and Biomedical Science

Heat-labile enterotoxin (LT) is an important virulence factor secreted by some strains of porcine-origin enterotoxigenic Escherichia coli (pETEC). The prototypic human-origin strain H10407 secretes LT via a type II secretion system (T2SS), but its presence or importance in pETEC has not been established. Exposure of pETEC to glucose has been shown to result in different secretion levels of LT. Furthermore, the relationship between the level of LT secreted and the virulence potential of the respective pETEC strain has not been established. To determine the relationship between the capacity to secrete LT and virulence in wild-type (WT) pETEC, 16 strains isolated ...


Influence Of Current Land Use And Edaphic Factors On Arbuscular Mycorrhizal (Am) Hyphal Abundance And Soil Organic Matter In And Near Serengeti National Park, Geofrey Soka 2015 Syracuse University

Influence Of Current Land Use And Edaphic Factors On Arbuscular Mycorrhizal (Am) Hyphal Abundance And Soil Organic Matter In And Near Serengeti National Park, Geofrey Soka

Geofrey Soka

Arbuscular mycorrhizal fungi (AMF) are important microbial symbionts for plants especially when soil phosphorus (P) and nitrogen (N) are limited. Little is known about the distribution of AM hyphae in natural systems of tropical soils across landscapes and their association with different land uses. We studied mycorrhizal hyphal abundance in a wildlife grazed system, a livestock grazed system and under cultivated soils in and near Serengeti National Park, Tanzania. Samples of the upper 15 cm of soil beneath locally dominant plant species were collected. Hyphae were preserved on permanent slides and the length of hyphae per cubic centimeter of soil ...


Assessing The Role Of A Putative Response Regulator In Sunscreen Biosynthesis In The Cyanobacterium Nostoc Punctiforme Atcc 29133, Sejuti Naurin 2015 Indiana University - Purdue University Fort Wayne

Assessing The Role Of A Putative Response Regulator In Sunscreen Biosynthesis In The Cyanobacterium Nostoc Punctiforme Atcc 29133, Sejuti Naurin

Masters' Theses

Under exposure to long-wavelength ultraviolet radiation (UVA), some cyanobacteria can produce scytonemin, a yellow to brown, lipid-soluble, non-fluorescent, stable sunscreen compound. A genomic region associated with scytonemin biosynthesis has been identified in the filamentous cyanobacterium Nostoc punctiforme ATCC 29133 that contains 18 adjacent genes transcribed in a single direction. Most of the genes in the upstream region of the cluster code for unique proteins involved directly in scytonemin biosynthesis. Further genomic characterization of this gene cluster in N. punctiforme has revealed a conserved putative two-component regulatory system (TCRS; NpF1277 and NpF1278) upstream and adjacent to the biosynthetic cluster that is ...


Exploring The Physiological Role Of Vibrio Fischeri Pepn, Sally L. Cello 2015 California Polytechnic State University, San Luis Obispo

Exploring The Physiological Role Of Vibrio Fischeri Pepn, Sally L. Cello

Master's Theses and Project Reports

The primary contributor to Vibrio fischeri aminopeptidase activity is aminopeptidase N, PepN. Colonization assays revealed the pepN mutant strain to be deficient at forming dense aggregates and populating the host’s light organ compared to wildtype within the first 12 hours of colonization; however the mutant competed normally at 24 hours. To address the role of PepN in colonization initiation and establish additional phenotypes for the pepN mutant strain, stress response and other physiological assays were employed. Marked differences were found between pepN mutant and wildtype strain in response to salinity, acidity, and antibiotic tolerance. This study has provided a ...


Mechanisms For Extracellular Electron Exchange By Geobacter Species, Jessica A. Smith 2015 University of Massachusetts - Amherst

Mechanisms For Extracellular Electron Exchange By Geobacter Species, Jessica A. Smith

Doctoral Dissertations May 2014 - current

Understanding the mechanisms for microbial extracellular electron exchange are of interest because these processes play an important role in the biogeochemical cycles of both modern and ancient environments, development of bioenergy strategies, as well as for bioremediation applications. Only a handful of microorganisms are capable of extracellular electron exchange, one of the most thoroughly studied being the Geobacter species. Geobacter species are often the predominant Fe(III) reducing microorganisms in many soils and sediments, can exchange electrons directly via interspecies electron transfer, and can both donate or accept electrons with a wide variety of extracellular substrates including the electrode of ...


Unveiling Novel Aspects Of D-Amino Acid Metabolism In The Model Bacterium Pseudomonas Putida Kt2440, Atanas D. Radkov 2015 University of Kentucky

Unveiling Novel Aspects Of D-Amino Acid Metabolism In The Model Bacterium Pseudomonas Putida Kt2440, Atanas D. Radkov

Theses and Dissertations--Plant and Soil Sciences

D-amino acids (D-AAs) are the α-carbon enantiomers of L-amino acids (L- AAs), the building blocks of proteins in known organisms. It was largely believed that D-AAs are unnatural and must be toxic to most organisms, as they would compete with the L-counterparts for protein synthesis. Recently, new methods have been developed that allow scientists to chromatographically separate the two AA stereoisomers. Since that time, it has been discovered that D-AAs are vital molecules and they have been detected in many organisms. The work of this dissertation focuses on their place in bacterial metabolism. This specific area was selected due to ...


Transcriptomic And Proteomic Dynamics In The Metabolism Of A Diazotrophic Cyanobacterium, Cyanothece Sp. Pcc 7822 During A Diurnal Light-Dark Cycle, Louis Sherman 2014 lsherman@purdue.edu

Transcriptomic And Proteomic Dynamics In The Metabolism Of A Diazotrophic Cyanobacterium, Cyanothece Sp. Pcc 7822 During A Diurnal Light-Dark Cycle, Louis Sherman

Louis A Sherman

Background: Cyanothece sp. PCC 7822 is an excellent cyanobacterial model organism with great potential to be applied as a biocatalyst for the production of high value compounds. Like other unicellular diazotrophic cyanobacterial species, it has a tightly regulated metabolism synchronized to the light-dark cycle. Utilizing transcriptomic and proteomic methods, we were able to quantify the relationships between transcription and translation underlying central and secondary metabolism in response to nitrogen free, 12 hour light and 12 hour dark conditions.

Results: By combining mass-spectrometry based proteomics and RNA-sequencing transcriptomics, we quantitatively measured a total of 6766 mRNAs and 1322 proteins at four ...


Comparative Genomics Of Microbial Chemoreceptor Sequence, Structure, And Function, Aaron Daniel Fleetwood 2014 University of Tennessee - Knoxville

Comparative Genomics Of Microbial Chemoreceptor Sequence, Structure, And Function, Aaron Daniel Fleetwood

Doctoral Dissertations

Microbial chemotaxis receptors (chemoreceptors) are complex proteins that sense the external environment and signal for flagella-mediated motility, serving as the GPS of the cell. In order to sense a myriad of physicochemical signals and adapt to diverse environmental niches, sensory regions of chemoreceptors are frenetically duplicated, mutated, or lost. Conversely, the chemoreceptor signaling region is a highly conserved protein domain. Extreme conservation of this domain is necessary because it determines very specific helical secondary, tertiary, and quaternary structures of the protein while simultaneously choreographing a network of interactions with the adaptor protein CheW and the histidine kinase CheA. This dichotomous ...


A Diverse Assemblage Of Indole-3-Acetic Acid Producing Bacteria Associate With Unicellular Green Algae, Christopher Bagwell, Magdalena Piskorska, Tanya Soule, Angela Petelos, Christopher Yeager 2014 Indiana University Purdue University, Fort Wayne

A Diverse Assemblage Of Indole-3-Acetic Acid Producing Bacteria Associate With Unicellular Green Algae, Christopher Bagwell, Magdalena Piskorska, Tanya Soule, Angela Petelos, Christopher Yeager

Tanya Soule

Microalgae have tremendous potential as a renewable feedstock for the production of liquid transportation fuels. In natural waters, the importance of physical associations and biochemical interactions between microalgae and bacteria is generally well appreciated, but the significance of these interactions to algal biofuels production have not been investigated. Here, we provide a preliminary report on the frequency of co-occurrence between indole-3-acetic acid (IAA)-producing bacteria and green algae in natural and engineered ecosystems. Growth experiments with unicellular algae, Chlorella and Scenedesmus, revealed IAA concentration-dependent responses in chlorophyll content and dry weight. Importantly, discrete concentrations of IAA resulted in cell culture ...


Physiological Models Of Geobacter Sulfurreducens And Desulfobacter Postgatei To Understand Uranium Remediation In Subsurface Systems, Roberto Orellana 2014 umass

Physiological Models Of Geobacter Sulfurreducens And Desulfobacter Postgatei To Understand Uranium Remediation In Subsurface Systems, Roberto Orellana

Doctoral Dissertations May 2014 - current

Geobacter species are often the predominant Fe(III)-reducing microorganisms in many sedimentary environments due to their capacity for extracellular electron transfer. This exceptional physiological capability allows them to couple acetate oxidation to uranium (U(VI)) reduction, that is one of the most significant interactions between radionuclides and microorganisms that naturally takes place in uranium-contaminated environments. Although this process has been proposed as a promising strategy for the in situ bioremediation of uranium-contaminated groundwater, little is known about the molecular mechanisms involved in U(VI) reduction and the interaction between Geobacter and other microbial species.

In the first two research ...


An In Vitro Model Of The Horse Gut Microbiome Enables Identification Of Lactate-Utilizing Bacteria That Differentially Respond To Starch Induction, Amy S. Biddle, Samuel J. Black, Jeffrey L. Blanchard 2014 University of Massachusetts Amherst

An In Vitro Model Of The Horse Gut Microbiome Enables Identification Of Lactate-Utilizing Bacteria That Differentially Respond To Starch Induction, Amy S. Biddle, Samuel J. Black, Jeffrey L. Blanchard

UMass Center for Clinical and Translational Science Research Retreat

Laminitis is a chronic, crippling disease triggered by the sudden influx of dietary starch. Starch reaches the hindgut resulting in enrichment of lactic acid bacteria, lactate accumulation, and acidification of the gut contents. Bacterial products enter the bloodstream and precipitate systemic inflammation. Hindgut lactate levels are normally low because specific bacterial groups convert lactate to short chain fatty acids. Why this mechanism fails when lactate levels rapidly rise, and why some hindgut communities can recover is unknown. Fecal samples from three adult horses eating identical diets provided bacterial communities for this in vitro study. Triplicate microcosms of fecal slurries were ...


Changes In The Microbial Community As A Potential Indicator Of Clandestine Drug Operations., Tanisha N. Payne 2014 University of North Texas Health Science Center

Changes In The Microbial Community As A Potential Indicator Of Clandestine Drug Operations., Tanisha N. Payne

Theses and Dissertations

Dust is a complex mixture of inorganic and organic materials including diverse microorganisms, which if unattended, accumulates over time. In this study, the microbial content in house dust was tested to determine its forensic detection potential in a model scenario mimicking the conditions of methamphetamine manufacturing. We hypothesized that microorganisms associated with the materials exposed to vapors will respond in a reproducible way. By identifying the microbial communities and any changes that may have occurred we expected to elucidate a correlation between microorganisms and the test chemicals involved, which was supported by the results presented. These findings may provide evidence ...


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