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Molecular Classification And Uv Tolerance Of Pigmented Antarctic Extremophiles, Aaron M. Perry 2017 University of Tennessee, Knoxville

Molecular Classification And Uv Tolerance Of Pigmented Antarctic Extremophiles, Aaron M. Perry

University of Tennessee Honors Thesis Projects

No abstract provided.


Anaerobic Oxidation Of Ethane, Propane, And Butane By Marine Microbes: A Mini Review, Rajesh Singh, Michael S. Guzman, Arpita Bose 2017 Washington University in St. Louis

Anaerobic Oxidation Of Ethane, Propane, And Butane By Marine Microbes: A Mini Review, Rajesh Singh, Michael S. Guzman, Arpita Bose

Biology Faculty Publications & Presentations

The deep ocean and its sediments are a continuous source of non-methane short-chain alkanes (SCAs) including ethane, propane, and butane. Their high global warming potential, and contribution to local carbon and sulfur budgets has drawn significant scientific attention. Importantly, microbes can use gaseous alkanes and oxidize them to CO2, thus acting as effective biofilters. A relative decrease of these gases with a concomitant 13C enrichment of propane and n-butane in interstitial waters vs. the source suggests microbial anaerobic oxidation. The reported uncoupling of sulfate-reduction (SR) from anaerobic methane oxidation supports their microbial consumption. To date, strain BuS5 ...


Candida And Pseudomonas Interact To Enhance Mucosal Infection In Transparent Zebrafish, Audrey C. Bergeron 2017 The University of Maine

Candida And Pseudomonas Interact To Enhance Mucosal Infection In Transparent Zebrafish, Audrey C. Bergeron

Electronic Theses and Dissertations

Polymicrobial communities exist throughout the human body and include both fungi and bacteria. During disease, cross-kingdom interactions among bacteria, fungi, and/or the immune system can alter virulence and lead to complex polymicrobial infections. The fungus C. albicans is among the most commonly isolated fungi in the context of fungal-bacterial co-infections and is often accompanied by the bacterium P. aeruginosa at a variety of sites throughout the body including mucosal tissues such as the lung. In vitro, C. albicans and P. aeruginosa have a cyclic, bi-directional, and largely antagonistic relationship, but these interactions do not account for the role of ...


Intestinal Organoids Model Human Responses To Infection By Commensal And Shiga Toxin Producing Escherichia Coli, Sayali S. Karve, Suman Pradhan, Doyle V. Ward, Alison A. Weiss 2017 University of Cincinnati

Intestinal Organoids Model Human Responses To Infection By Commensal And Shiga Toxin Producing Escherichia Coli, Sayali S. Karve, Suman Pradhan, Doyle V. Ward, Alison A. Weiss

Open Access Articles

Infection with Shiga toxin (Stx) producing Escherichia coli O157:H7 can cause the potentially fatal complication hemolytic uremic syndrome, and currently only supportive therapy is available. Lack of suitable animal models has hindered study of this disease. Induced human intestinal organoids (iHIOs), generated by in vitro differentiation of pluripotent stem cells, represent differentiated human intestinal tissue. We show that iHIOs with addition of human neutrophils can model E. coli intestinal infection and innate cellular responses. Commensal and O157:H7 introduced into the iHIO lumen replicated rapidly achieving high numbers. Commensal E. coli did not cause damage, and were completely contained ...


Development Of A Core Clostridium Thermocellum Kinetic Metabolic Model Consistent With Multiple Genetic Perturbations, Satyakam Dash, Ali Khodayari, Jilai Zhou, Evert K. Holwerda, Daniel Olson, Lee Lynd, Costas Maranas 2017 The Pennsylvania State University

Development Of A Core Clostridium Thermocellum Kinetic Metabolic Model Consistent With Multiple Genetic Perturbations, Satyakam Dash, Ali Khodayari, Jilai Zhou, Evert K. Holwerda, Daniel Olson, Lee Lynd, Costas Maranas

Open Dartmouth: Faculty Open Access Articles

Clostridium thermocellum is a Gram-positive anaerobe with the ability to hydrolyze and metabolize cellulose into biofuels such as ethanol, making it an attractive candidate for consolidated bioprocessing (CBP). At present, metabolic engineering in C. thermocellum is hindered due to the incomplete description of its metabolic repertoire and regulation within a predictive metabolic model. Genome-scale metabolic (GSM) models augmented with kinetic models of metabolism have been shown to be effective at recapitulating perturbed metabolic phenotypes.

In this effort, we first update a second-generation genome-scale metabolic model (iCth446) for C. thermocellum by correcting cofactor dependencies, restoring elemental and charge balances, and ...


Self-Assembled Cationic Amphiphiles As Antimicrobial Peptides Mimics: Role Of Hydrophobicity, Linkage Type, And Assembly State, Yingyue Zhang 2017 Princeton University

Self-Assembled Cationic Amphiphiles As Antimicrobial Peptides Mimics: Role Of Hydrophobicity, Linkage Type, And Assembly State, Yingyue Zhang

Yingyue Zhang

Inspired by high promise using naturally occurring antimicrobial peptides (AMPs) to treat infections caused by antimicrobial-resistant bacteria, cationic amphiphiles (CAms) were strategically designed as synthetic mimics to overcome associated limitations, including high manufacture cost and low metabolic stability. CAms with facially amphiphilic conformation were expected to demonstrate membrane-lytic properties and thus reduce tendency of resistance development. By systematically tuning the hydrophobicity, CAms with optimized compositions exhibited potent broad-spectrum antimicrobial activity (with minimum inhibitory concentrations in low μg/mL range) as well as negligible hemolytic activity. Electron microscope images revealed the morphological and ultrastructure changes of bacterial membranes induced by CAm ...


Scanning Labyrinthulomycete Genomes For Yeast Transcription Factor Binding Site Motifs, Jackie L. Collier, Joshua Rest 2017 SUNY Stony Brook

Scanning Labyrinthulomycete Genomes For Yeast Transcription Factor Binding Site Motifs, Jackie L. Collier, Joshua Rest

Interdisciplinary Research Data

To develop broadly useful methods for the genetic manipulation of Labyrinthulomycetes (a diverse group of ubiquitous osmoheterotrophic marine protists), it is essential to understand the similarities and differences in regulation of gene expression among them. Toward this end we have used FIMO from the MEME suite (http://meme-suite.org/doc/fimo.html) to identify potential transcription factor binding sites in each of the three available genome sequences: Aplanochytrium kerguelense PBS07, Schizochytrium aggregatum ATCC 28209, and Aurantiochytrium limacinum ATCC MYA-1381


Measuring Bacterial Growth Using A 3d-Printable Spectrometer, Samuel R. Bunting 2017 The University of Akron

Measuring Bacterial Growth Using A 3d-Printable Spectrometer, Samuel R. Bunting

Honors Research Projects

Visible light spectroscopy is a commonly used technique for measuring the growth of bacterial cultures, and growth curves provide broadly important data. However, the equipment and resources required for these experiments has been restricted to higher education and industry due to high cost and sophistication. We have previously reported on an inexpensive, 3D-printable photospectrometer called the SpecPhone. This device utilizes an iPhone as the camera, along with several other, inexpensive additions to make a fully functional spectrometer. Here, the application of the SpecPhone is expanded to the quantification of actively dividing E. coli cultures. Two protocols have been developed; one ...


Proteomic Approach For Extracting Cytoplasmic Proteins From Streptococcus Sanguinis Using Mass Spectrometry, Fadi Elrami, Kristina Nelson, Ping Xu 2017 Virginia Commonwealth University

Proteomic Approach For Extracting Cytoplasmic Proteins From Streptococcus Sanguinis Using Mass Spectrometry, Fadi Elrami, Kristina Nelson, Ping Xu

Philips Institute for Oral Health Research Publications

Streptococcus sanguinis is a commensal and early colonizer of oral cavity as well as an opportunistic pathogen of infectious endocarditis. Extracting the soluble proteome of this bacterium provides deep insights about the physiological dynamic changes under different growth and stress conditions, thus defining “proteomic signatures” as targets for therapeutic intervention. In this protocol, we describe an experimentally verified approach to extract maximal cytoplasmic proteins from Streptococcus sanguinis SK36 strain. A combination of procedures was adopted that broke the thick cell wall barrier and minimized denaturation of the intracellular proteome, using optimized buffers and a sonication step. Extracted proteome was quantitated ...


Discovery And Characterization Of Bile Acid And Steroid Metabolism Pathways In Gut-Associated Microbes, Spencer Harris 2017 Virginia Commonwealth University

Discovery And Characterization Of Bile Acid And Steroid Metabolism Pathways In Gut-Associated Microbes, Spencer Harris

Theses and Dissertations

The human gut microbiome is a complex microbial ecosystem residing in the lumen of our gastrointestinal tract. The type and amounts of microbes present in this ecosystem varies based on numerous factors, including host genetics, diet, and environmental factors. The human gut microbiome plays an important role in normal host physiological functions, including providing energy to colonocytes in the form of short-chain fatty acids. However, gut microbial metabolites have also been associated with numerous disease states. Current tools for analyzing the gut microbiome, such as high-throughput sequencing techniques, are limited in their predictive ability. Additionally, “-omic” approaches of studying the ...


Loss Of Outer Membrane Porins In Clonally Related Clinical Isolates Of Klebsiella Pneumoniae Modifies The Bacteria; Resulting In Altered Resistance To Phagocytosis By Macrophages, Debra Nickole Brunson 2017 University of North Florida

Loss Of Outer Membrane Porins In Clonally Related Clinical Isolates Of Klebsiella Pneumoniae Modifies The Bacteria; Resulting In Altered Resistance To Phagocytosis By Macrophages, Debra Nickole Brunson

UNF Graduate Theses and Dissertations

Klebsiella pneumoniae is an opportunistic pathogen responsible for lobar pneumoniae, liver abscess, and septicemia. Clinical isolates are found to be extended spectrum beta lactamase positive with differential expression of the two classical porins, OmpK35 and OmpK36. Porin loss is associated with increased minimum inhibitory concentrations of beta lactam, cephalosporin, and carbapenem antibiotics that target the peptidoglycan. However, little is known about how porin loss affects other aspects of the cell envelope. The focus of this study was to characterize clinical isolates exhibiting differential porin expression and determine if the cumulative changes altered the resistance to phagocytosis by macrophages. The results ...


Analysis Of The Prevention Of Biocorrosion Caused By Desulfovibrio Alaskensis G20, Michael Boring 2017 University of Central Florida

Analysis Of The Prevention Of Biocorrosion Caused By Desulfovibrio Alaskensis G20, Michael Boring

Honors in the Major Theses

Desulfovibrio alaskensis G20 and other sulfate-reducing bacteria cause significant damage to metal pipelines and other infrastructure through a metabolic pathway that releases toxic hydrogen sulfide into their surroundings. The biocorrosion that results from the release of hydrogen sulfide creates significant economic burden, and can pose health risks for those exposed to this chemical. They are commonly present in the form of biofilms, an extracellular matrix composed of bacterial cells, polysaccharides, proteins, nucleic acids, and other materials. These biofilms are difficult to remove, and they provide protection to the bacteria within from anti-bacterial treatments. Desulfovibrio alaskensis G20 is a strain derived ...


Letter From The Dean, Lona Robertson 2017 University of Arkansas, Fayetteville

Letter From The Dean, Lona Robertson

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.


Jmh Dissertation 2016.Pdf, Jennifer Hayashi 2016 University of Massachusetts - Amherst

Jmh Dissertation 2016.Pdf, Jennifer Hayashi

Jennifer Hayashi

Mycobacterium is a diverse genus of actinobacteria that includes the causative agents of human tuberculosis and leprosy. Mycobacteria are protected by their unique, multilaminar cell envelope, which grants them intrinsic resistance to environmental challenges such as antibiotics. This essential cellular structure is elongated at the polar ends of cells, but the regulation of cytosolic precursor synthesis and localized envelope synthesis remains unclear. Here, we present the PMf (plasma membrane free of cell wall components), a membrane domain distinct from the bulk plasma membrane of Mycobacterium smegmatis. Proteomic and lipidomic characterization demonstrate that the PMf contains lipidic substrates ...


Tetrameric Photosystem I: From Initial Discovery And Characterization In Chroococcidiopsis Sp. Ts-821 To Exploration Of Its Distribution And Understanding Of Its Significance In Cyanobacteria, Meng Li 2016 University of Tennessee, Knoxville

Tetrameric Photosystem I: From Initial Discovery And Characterization In Chroococcidiopsis Sp. Ts-821 To Exploration Of Its Distribution And Understanding Of Its Significance In Cyanobacteria, Meng Li

Doctoral Dissertations

Photosystem I (PSI) forms trimeric complexes in most characterized cyanobacteria. We had reported the tetrameric form of PSI in the unicellular cyanobacterium, Chroococcidiopsis sp. TS-821 (TS-821). Using Cryo-EM, a 3D model of the PSI tetramer structure at 11.5 [Angstrom] resolution was obtained and a 2D map within the membrane plane of at 6.1 [Angstrom]. In contrast to the three-fold symmetry in trimeric PSI crystal structure from T. elongatus, two different inter-monomer interactions involving PsaLs are found in the PSI tetramer. Phylogenetic analysis based on PsaL protein sequences shows that TS-821 is closely related to heterocyst-forming cyanobacteria. Additionally, this ...


Identification Of Essential Metabolic And Genetic Adaptations To The Quiescent State In Mycobacterium Tuberculosis: A Dissertation, Emily S. C. Rittershaus 2016 University of Massachusetts Medical School

Identification Of Essential Metabolic And Genetic Adaptations To The Quiescent State In Mycobacterium Tuberculosis: A Dissertation, Emily S. C. Rittershaus

GSBS Dissertations and Theses

Mycobacterium tuberculosis stably adapts to respiratory limited environments by entering into a nongrowing but metabolically active state termed quiescence. This state is inherently tolerant to antibiotics due to a reduction in growth and activity of associated biosynthetic pathways. Understanding the physiology of the quiescent state, therefore, may be useful in developing new strategies to improve drug efficiency. Here, we used an established in vitro model of respiratory stress, hypoxia, to induce quiescence. We utilized metabolomic and genetic approaches to identify essential and active pathways associated with nongrowth. Our metabolomic profile of hypoxic M. tuberculosis revealed an increase in several free ...


Spot 42 Srna Regulates Arabinose-Inducible Arabad Promoter Activity By Repressing Synthesis Of The High-Affinity Low-Capacity Arabinose Transporter., Jiandong Chen, Susan Gottesman 2016 National Cancer Institute

Spot 42 Srna Regulates Arabinose-Inducible Arabad Promoter Activity By Repressing Synthesis Of The High-Affinity Low-Capacity Arabinose Transporter., Jiandong Chen, Susan Gottesman

Jiandong Chen

The L-arabinose-inducible araBAD promoter (PBAD) allows tightly controlled and tunable expression of genes of interest in a broad range of bacterial species. It has been successfully used to study bacterial sRNA regulation, where PBAD drives expression of target mRNA translational fusions. Here we report that in Escherichia coli, Spot 42 sRNA can regulate PBAD promoter activity by affecting arabinose uptake. We demonstrate that Spot 42 sRNA represses araF, a gene encoding the AraF subunit of the high-affinity low-capacity arabinose transporter AraFGH, through direct base pairing interactions. We further show that endogenous Spot 42 sRNA is sufficient to ...


The Roles Of Biotin In Candida Albicans Physiology, Nur Ras Aini Ahmad Hussin 2016 University of Nebraska-Lincoln

The Roles Of Biotin In Candida Albicans Physiology, Nur Ras Aini Ahmad Hussin

Dissertations and Theses in Biological Sciences

Due to the increased number of immunocompromised patients, infections by Candida albicans have significantly increased in recent years. C. albicans transition from yeast to germ tubes is an essential factor for virulence. In this study we noted that Lee's medium, commonly used to induce filamentation, contained 500-fold more biotin than needed for growth. Thus, we investigated the effects of excess biotin on growth rate and filamentation by C. albicans in different media. At 37 °C, excess biotin (4 µM) enhanced germ tube formation (GTF) ca. 10-fold in both Lee's medium and a defined glucose proline medium, and ca ...


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 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 ...


The Effects Of Exogenous Fatty Acids On Enterococcus Faecalis Og1rf, Holly Elizabeth Johnson Saito 2016 University of Tennessee, Knoxville

The Effects Of Exogenous Fatty Acids On Enterococcus Faecalis Og1rf, Holly Elizabeth Johnson Saito

Doctoral Dissertations

Enterococcus faecalis is a commensal of the mammalian intestine and an opportunistic pathogen that infects various locations in the human host. Specifically, the organism can infect surgical wounds, the urinary tract, and is an agent of endocarditis. Regardless of niche, this organism has access to fatty acid sources in the host, which may influence its ability to survive and cause infection; yet, the effects of exogenous fatty acids were unknown in E. faecalis. We have shown that complex sources of fatty acids such as bile or serum can significantly alter the membrane content and protect E. faecalis from acute membrane ...


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