Characterization Of Antimicrobial Activity Of Culturable Bacteria Isolated From Krubera-Voronja Cave, 2016 Vilnius University
Characterization Of Antimicrobial Activity Of Culturable Bacteria Isolated From Krubera-Voronja Cave, Aiste Klusaite, Vida Vickackaite, Birute Vaitkeviciene, Rasa Karnickaite, Dominykas Bukelskis, Ieva Kieraite-Aleksandrova, Nomeda Kuisiene
International Journal of Speleology
In the present study we aimed to perform the first analysis of antimicrobial activity of bacteria isolated from Krubera-Voronja Cave, with the main focus on their activity against Grampositive bacteria, including Gram-positive pathogens. Using five different media, in total 874 heterotrophic cultures were isolated from water and sediment samples collected in Krubera-Voronja Cave at a depth from 220 m to 1640 m. 14.0% of all isolates demonstrated antibacterial activity against Gram-positive and Gram-negative test microorganisms. Our results show that this percentage was not uniform; it increased with the sampling depth and was the highest in the lower part of ...
Biosynthesis And Roles Of Virulence Conferring Cell Wall Associated Dimycocerosate Esters In Mycobacterium Marinum, 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, 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, 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., 2016 University of Tennessee - Knoxville
Environmentally Driven Orchestration Of Metabolisms By Prochlorococcus Spp., Martin James Szul
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 ...
Xct Increases Tuberculosis Susceptibility By Regulating Antimicrobial Function And Inflammation, 2016 Guangdong Medical College
Xct Increases Tuberculosis Susceptibility By Regulating Antimicrobial Function And Inflammation, Yi Cai, Subhalaxmi Nambi, Christopher M. Sassetti, Fudi Wang, Xinchun Chen
Open Access Articles
The physiological functions of macrophage, which plays a central role in the pathogenesis of tuberculosis, depend on its redox state. System xc-, a cystine-glutamate transporter, which consists of xCT and CD98, influences many ROS-dependent pathways by regulating the production of the antioxidant glutathione. xCT's ability to alter this critical host redox balance by increasing the glutathione synthesis aspect of phagocyte physiology suggested that it might influence tuberculosis pathogenesis. In this study, we found that the xCT expression was increased in peripheral blood monocyte of active tuberculosis. xCT expression in macrophage was induced by Mycobacterium tuberculosis (Mtb) through TLR2/Akt- ...
Toxicity Of Engineered Nanomaterials To Plant Growth Promoting Rhizobacteria, 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, 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, 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, 2015 University of Tennessee - Knoxville
The Role Of Phosphatidylserine And Phosphatidylethanolamine In Candida Albicans Virulence, Sarah Elizabeth Davis
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, 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
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, 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
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, 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, 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, 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
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, 2014 University of Tennessee - Knoxville
Comparative Genomics Of Microbial Chemoreceptor Sequence, Structure, And Function, Aaron Daniel Fleetwood
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, 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
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
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 ...