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Possible Nonconductive Role Of Geobacter Sulfurreducens Pilus Nanowires In Biofilm Formation, Gemma Reguera, Rachael B. Pollina, Julie S. Nicoll, Derek Lovley Dec 2006

Possible Nonconductive Role Of Geobacter Sulfurreducens Pilus Nanowires In Biofilm Formation, Gemma Reguera, Rachael B. Pollina, Julie S. Nicoll, Derek Lovley

Derek Lovley

Geobacter sulfurreducens required expression of electrically conductive pili to form biofilms on Fe(III) oxide surfaces, but pili were also essential for biofilm development on plain glass when fumarate was the sole electron acceptor. Furthermore, pili were needed for cell aggregation in agglutination studies. These results suggest that the pili of G. sulfurreducens also have a structural role in biofilm formation.


Bmc Infectious Diseases, Frances Cirino, Wilmore C. Webley, Corrie West, Nancy L. Croteau, Chester Andrzejewski Jr, Elizabeth S. Stuart Nov 2006

Bmc Infectious Diseases, Frances Cirino, Wilmore C. Webley, Corrie West, Nancy L. Croteau, Chester Andrzejewski Jr, Elizabeth S. Stuart

Wilmore C Webley

No abstract provided.


An Anaerobic Methane Oxidizing Community Of Anme-1b Archaea In Hypersaline Gulf Of Mexico Sediments, Karen Lloyd, Laura Lapham, Andreas Teske Oct 2006

An Anaerobic Methane Oxidizing Community Of Anme-1b Archaea In Hypersaline Gulf Of Mexico Sediments, Karen Lloyd, Laura Lapham, Andreas Teske

Karen Lloyd

Sediments overlying a brine pool methane seep in the Gulf of Mexico (Green Canyon 205) were analyzed using molecular and geochemical approaches to identify geochemical controls on microbial community composition and stratification. 16S rRNA gene and rRNA clone libraries, as well as mcrA gene clone libraries, showed that the archaeal community consists predominantly of ANME-1b methane oxidizers; no archaea of other ANME subgroups were found with general and group-specific PCR primers. The ANME-1b community was found in the sulfate-methane interface, where undersaturated methane concentrations of ca. 100 to 250 _M coexist with sulfate concentrations around 10 mM. Clone libraries of ...


Role Of Red Gsu In Stress Response And Fe(Iii) Reduction In Geobacter Sulfurreducens, Laurie N. Didonato, Sara A. Sullivan, Barbara A. Methѐ, Kelly P. Nevin, Reg England, Derek Lovley Oct 2006

Role Of Red Gsu In Stress Response And Fe(Iii) Reduction In Geobacter Sulfurreducens, Laurie N. Didonato, Sara A. Sullivan, Barbara A. Methѐ, Kelly P. Nevin, Reg England, Derek Lovley

Kelly Nevin

Geobacter species are key members of the microbial community in many subsurface environments in which dissimilatory metal reduction is an important process. The genome of Geobacter sulfurreducens contains a gene designated relGsu, which encodes a RelA homolog predicted to catalyze both the synthesis and the degradation of guanosine 3′,5′-bispyrophosphate (ppGpp), a regulatory molecule that signals slow growth in response to nutrient limitation in bacteria. To evaluate the physiological role of RelGsu in G. sulfurreducens, a relGsu mutant was constructed and characterized, and ppGpp levels were monitored under various conditions in both the wild-type and relGsu mutant strains. In ...


Role Of Red Gsu In Stress Response And Fe(Iii) Reduction In Geobacter Sulfurreducens, Laurie N. Didonato, Sara A. Sullivan, Barbara A. Methѐ, Kelly P. Nevin, Reg England, Derek Lovley Oct 2006

Role Of Red Gsu In Stress Response And Fe(Iii) Reduction In Geobacter Sulfurreducens, Laurie N. Didonato, Sara A. Sullivan, Barbara A. Methѐ, Kelly P. Nevin, Reg England, Derek Lovley

Derek Lovley

Geobacter species are key members of the microbial community in many subsurface environments in which dissimilatory metal reduction is an important process. The genome of Geobacter sulfurreducens contains a gene designated relGsu, which encodes a RelA homolog predicted to catalyze both the synthesis and the degradation of guanosine 3′,5′-bispyrophosphate (ppGpp), a regulatory molecule that signals slow growth in response to nutrient limitation in bacteria. To evaluate the physiological role of RelGsu in G. sulfurreducens, a relGsu mutant was constructed and characterized, and ppGpp levels were monitored under various conditions in both the wild-type and relGsu mutant strains. In ...


Cj1121c, A Novel Udp-4-Keto-6-Deoxy-Glcnac C-4 Aminotransferase Essential For Protein Glycosylation And Virulence In Campylobacter Jejuni, Somalinga Vijayakumar, Alexandra Merkx-Jacques, Dinath Ratnayake, Irene Gryski, Ravinder Obhi, Sébastien Houle, Charles M Dozois, Carole Creuzenet Sep 2006

Cj1121c, A Novel Udp-4-Keto-6-Deoxy-Glcnac C-4 Aminotransferase Essential For Protein Glycosylation And Virulence In Campylobacter Jejuni, Somalinga Vijayakumar, Alexandra Merkx-Jacques, Dinath Ratnayake, Irene Gryski, Ravinder Obhi, Sébastien Houle, Charles M Dozois, Carole Creuzenet

Alexandra Merkx-Jacques

Campylobacter jejuni produces glycoproteins that are essential for virulence. These glycoproteins carry diacetamidobacillosamine (DAB), a sugar that is not found in humans. Hence, the enzymes responsible for DAB synthesis represent potential therapeutic targets. We describe the biochemical characterization of Cj1121c, a putative aminotransferase encoded by the general protein glycosylation locus, to assess its role in DAB biosynthesis. By using overexpressed and affinity-purified enzyme, we demonstrate that Cj1121c has pyridoxal phosphate- and glutamate-dependent UDP-4-keto-6-deoxy-GlcNAc C-4 transaminase activity and produces UDP-4-amino-4,6-dideoxy-GlcNAc. This is consistent with a role in DAB biosynthesis and distinguishes Cj1121c from Cj1294, a homologous UDP-2-acetamido-2,6-dideoxy-beta-l-arabino-4-hexulose C-4 aminotransferase ...


Biofilm And Nanowire Production Leads To Increased Current In Geobacter Sulfurreducens Fuel Cells, Gemma Reguera, Kelly P. Nevin, Julie S. Nicoll, Sean F. Covalla, Trevor L. Woodard, Derek Lovley Aug 2006

Biofilm And Nanowire Production Leads To Increased Current In Geobacter Sulfurreducens Fuel Cells, Gemma Reguera, Kelly P. Nevin, Julie S. Nicoll, Sean F. Covalla, Trevor L. Woodard, Derek Lovley

Derek Lovley

Geobacter sulfurreducens developed highly structured, multilayer biofilms on the anode surface of a microbial fuel cell converting acetate to electricity. Cells at a distance from the anode remained viable, and there was no decrease in the efficiency of current production as the thickness of the biofilm increased. Genetic studies demonstrated that efficient electron transfer through the biofilm required the presence of electrically conductive pili. These pili may represent an electronic network permeating the biofilm that can promote long-range electrical transfer in an energy-efficient manner, increasing electricity production more than 10-fold.


Biofilm And Nanowire Production Leads To Increased Current In Geobacter Sulfurreducens Fuel Cells, Gemma Reguera, Kelly P. Nevin, Julie S. Nicoll, Sean F. Covalla, Trevor L. Woodard, Derek Lovley Aug 2006

Biofilm And Nanowire Production Leads To Increased Current In Geobacter Sulfurreducens Fuel Cells, Gemma Reguera, Kelly P. Nevin, Julie S. Nicoll, Sean F. Covalla, Trevor L. Woodard, Derek Lovley

Kelly Nevin

Geobacter sulfurreducens developed highly structured, multilayer biofilms on the anode surface of a microbial fuel cell converting acetate to electricity. Cells at a distance from the anode remained viable, and there was no decrease in the efficiency of current production as the thickness of the biofilm increased. Genetic studies demonstrated that efficient electron transfer through the biofilm required the presence of electrically conductive pili. These pili may represent an electronic network permeating the biofilm that can promote long-range electrical transfer in an energy-efficient manner, increasing electricity production more than 10-fold.


Probability Of Real -Time Detection Vs Probability Of Infection For Aerosolized Biowarfare Agents: A Model Study., Alexander G. Sabelnikov, Vladimir Zhukov, C Ruth Kempf May 2006

Probability Of Real -Time Detection Vs Probability Of Infection For Aerosolized Biowarfare Agents: A Model Study., Alexander G. Sabelnikov, Vladimir Zhukov, C Ruth Kempf

Alexander G Sabelnikov

No abstract provided.


Induced Biliary Excretion Of Listeria Monocytogenes, Jonathan Hardy, Jeffrey J. Margolis, Christopher H. Contag Feb 2006

Induced Biliary Excretion Of Listeria Monocytogenes, Jonathan Hardy, Jeffrey J. Margolis, Christopher H. Contag

Jeffrey Margolis

Listeria monocytogenes is a ubiquitous gram-positive bacterium that can cause systemic and often lifethreatening
disease in immunocompromised hosts. This organism is largely an intracellular pathogen; however,
we have determined that it can also grow extracellularly in animals, in the lumen of the gallbladder. The
significance of growth in the gallbladder with respect to the pathogenesis and spread of listeriosis depends on
the ability of the bacterium to leave this organ and be disseminated to other tissues and into the environment.
Should this process be highly inefficient, growth in the gallbladder would have no impact on pathogenesis or
spread, but if ...


Induction Of Temperate Cyanophage As-1 By Heavy Metal - Copper, Lee Lee, Lui Doris, Patricia Platner, Shi-Fang Hsu, Tin-Chun Chu, John Gaynor, Quinn Vega, Bonnie Lustigman Jan 2006

Induction Of Temperate Cyanophage As-1 By Heavy Metal - Copper, Lee Lee, Lui Doris, Patricia Platner, Shi-Fang Hsu, Tin-Chun Chu, John Gaynor, Quinn Vega, Bonnie Lustigman

Tin-Chun Chu, Ph.D.

No abstract provided.


Two Putative C-Type Multiheme Cytochromes Required For The Expression Of Omcb, And Outer Membrane Protein Essential For Optimal Fe(Iii) Reduction In Geobacter Sulfurreducens, Byoung-Chan Kim, Xinlei Qian, Ching Leang, Maddalena V. Coppi, Derek Lovley Jan 2006

Two Putative C-Type Multiheme Cytochromes Required For The Expression Of Omcb, And Outer Membrane Protein Essential For Optimal Fe(Iii) Reduction In Geobacter Sulfurreducens, Byoung-Chan Kim, Xinlei Qian, Ching Leang, Maddalena V. Coppi, Derek Lovley

Derek Lovley

Deletion of two homologous Geobacter sulfurreducens c-type cytochrome genes, omcG and omcH, decreased the rate of Fe(III) reduction and decreased the level of an outer membrane cytochrome critical for Fe(III) reduction, OmcB, without affecting its transcription. Expression of either gene restored Fe(III) reduction and OmcB expression, suggesting functional similarity.


Dna Microarray And Proteomic Analyses Of The Rpos Regulon In Geobacter Sulfurreducens, Carol Giometti, Cinthia Núñez, Sandra Tollaksen, Abraham Esteve-Núñez, Tripti Khare, Winston Lin, Derek Lovley, Barbara Methѐ Jan 2006

Dna Microarray And Proteomic Analyses Of The Rpos Regulon In Geobacter Sulfurreducens, Carol Giometti, Cinthia Núñez, Sandra Tollaksen, Abraham Esteve-Núñez, Tripti Khare, Winston Lin, Derek Lovley, Barbara Methѐ

Derek Lovley

The regulon of the sigma factor RpoS was defined in Geobacter sulfurreducens by using a combination of DNA microarray expression profiles and proteomics. An rpoS mutant was examined under steady-state conditions with acetate as an electron donor and fumarate as an electron acceptor and with additional transcriptional profiling using Fe(III) as an electron acceptor. Expression analysis revealed that RpoS acts as both a positive and negative regulator. Many of the RpoS-dependent genes determined play roles in energy metabolism, including the tricarboxylic acid cycle, signal transduction, transport, protein synthesis and degradation, and amino acid metabolism and transport. As expected, RpoS ...


Desiccation Responses And Survival Of Sinorhizobium Meliloti Usda 1021 In Relation To Growth Phase, Temperature, Chloride And Sulfate Availability, Jan A.C. Vriezen Dr., Frans J. Debruijn Dr., Klaus R. Nusslein Dr. Jan 2006

Desiccation Responses And Survival Of Sinorhizobium Meliloti Usda 1021 In Relation To Growth Phase, Temperature, Chloride And Sulfate Availability, Jan A.C. Vriezen Dr., Frans J. Debruijn Dr., Klaus R. Nusslein Dr.

Jan A.C. Vriezen Dr.

Aims: To identify physical and physiological conditions that affect the survival of Sinorhizobium meliloti USDA 1021 during desiccation. Methods and Results: An assay was developed to study desiccation response of S. meliloti USDA 1021 over a range of environmental conditions. We deter- mined the survival during desiccation in relation to (i) matrices and media, (ii) growth phase, (iii) temperature, and (iv) chloride and sulfate availability. Conclusions: This study indicates that survival of S. meliloti USDA 1021 during desiccation is enhanced: (i) when cells were dried in the stationary phase, (ii) with increasing drying temperature at an optimum of 37°C ...


Phenotypic And Genetic Parameters Of Reproductive Traits For Ayrshire Cattle On Large-Scale Farms In Kenya, Joshua O. Amimo Jan 2006

Phenotypic And Genetic Parameters Of Reproductive Traits For Ayrshire Cattle On Large-Scale Farms In Kenya, Joshua O. Amimo

Joshua O Amimo

No abstract provided.


Survival And Growth Of Two Heterotrophic Hydrothermal Vent Archaea, Pyrococcus Strain Gb-D And Thermococcus Fumicolans, Under Low Ph And High Sulfide Concentrations In Combination With High Temperature And Pressure Regimes, Virginia Edgcomb, Stephen Molyneaux, Simone Böer, Carl Wirsen, Mark Saito, Michael Atkins, Karen Lloyd, Andreas Teske Dec 2005

Survival And Growth Of Two Heterotrophic Hydrothermal Vent Archaea, Pyrococcus Strain Gb-D And Thermococcus Fumicolans, Under Low Ph And High Sulfide Concentrations In Combination With High Temperature And Pressure Regimes, Virginia Edgcomb, Stephen Molyneaux, Simone Böer, Carl Wirsen, Mark Saito, Michael Atkins, Karen Lloyd, Andreas Teske

Karen Lloyd

Growth and survival of hyperthermophilic archaea in their extreme hydrothermal vent and subsurface environments are controlled by chemical and physical key parameters. This study examined the effects of elevated sulfide concentrations, temperature, and acidic pH on growth and survival of two hydrothermal vent archaea (Pyrococcus strain GB-D and Thermococcus fumicolans) under high temperature and pressure regimes. These two strains are members of the Thermococcales, a family of hyperthermophilic, heterotrophic, sulfur-reducing archaea that occur in high densities at vent sites. As actively growing cells, these two strains tolerated regimes of pH, pressure, and temperature that were in most cases not tolerated ...


Lactobacillus Vaginal Microbiota Of Women Attending A Reproductive Health Care Service In Benin City, Nigeria., Kingsley Anukam, Emmanuel Osazuwa, Ijeoma Ahonkhai, Gregor Reid Dec 2005

Lactobacillus Vaginal Microbiota Of Women Attending A Reproductive Health Care Service In Benin City, Nigeria., Kingsley Anukam, Emmanuel Osazuwa, Ijeoma Ahonkhai, Gregor Reid

Kingsley C Anukam

OBJECTIVE: The objective of this study was to determine whether Lactobacillus species found in African women differ substantially to those of Caucasian decent, described in previous studies. The vaginal microbiota play an important role in female health, and when the naturally dominant lactobacilli are displaced resulting in bacterial vaginosis (BV), the host is more at risk of acquiring sexually transmitted diseases, including HIV. METHODS: Vaginal samples were collected from 241 healthy, pre-menopausal Nigerian women, which were then Gram stained for Nugent scoring. Microbial DNA was extracted, amplified using PCR and Lactobacillus primers, and processed by Denaturing Gradient Gel Electrophoresis (DGGE ...


Investigating The Glycosylation Of Groel And Its Role In The Virulence Of Campylobacter Jejuni, Alexandra Merkx-Jacques, I. Gryski, C. Creuzenet Dec 2005

Investigating The Glycosylation Of Groel And Its Role In The Virulence Of Campylobacter Jejuni, Alexandra Merkx-Jacques, I. Gryski, C. Creuzenet

Alexandra Merkx-Jacques

Campylobacter jejuni is a food-borne human pathogen and a major cause of gastroenteritis, reactive arthritis and neurological disorders. Due to emerging drug resistant strains, new treatments and/or vaccines need to be developed.

Protein glycosylation, or the post-translational modification of proteins by sugar molecules, plays an important role in this bacterium's virulence including affecting cell-host interactions, immunogenicity and pathogenicity. C jejuni harbours numerous proteins glycosylated by a heptasaccharide containing diacetamidobacillosamine. Our laboratory investigates the enzymes required to make this sugar as well as the glycoproteins on which this glycan is found.

Analysis of C jejuni proteins by Western blot ...


Heterotrophic Archaea Dominate Sedimentary Subsurface Ecosystems Off Peru, Jennifer Biddle, Julius Lipp, Karen Lloyd, Ketil Sørensen, Rika Anderson, Helen Fredericks, Marcus Elvert, Timothy Kelly, Daniel Schrag, Mitchell Sogin, Jean Brenchley, Andreas Teske, Christopher House, Kaw-Uwe Hinrichs Dec 2005

Heterotrophic Archaea Dominate Sedimentary Subsurface Ecosystems Off Peru, Jennifer Biddle, Julius Lipp, Karen Lloyd, Ketil Sørensen, Rika Anderson, Helen Fredericks, Marcus Elvert, Timothy Kelly, Daniel Schrag, Mitchell Sogin, Jean Brenchley, Andreas Teske, Christopher House, Kaw-Uwe Hinrichs

Karen Lloyd

Studies of deeply buried, sedimentary microbial communities and associated biogeochemical processes during Ocean Drilling Program Leg 201 showed elevated prokaryotic cell numbers in sediment layers where methane is consumed anaerobically at the expense of sulfate. Here, we show that extractable archaeal rRNA, selecting only for active community members in these ecosystems, is dominated by sequences of uncultivated Archaea affiliated with the Marine Benthic Group B and the Miscellaneous Crenarchaeotal Group, whereas known methanotrophic Archaea are not detectable. Carbon flow reconstructions based on stable isotopic compositions of whole archaeal cells, intact archaeal membrane lipids, and other sedimentary carbon pools indicate that ...


Toward A Conceptual And Operational Union Of Bacterial Systematics, Ecology, And Evolution, Frederick M. Cohan Dec 2005

Toward A Conceptual And Operational Union Of Bacterial Systematics, Ecology, And Evolution, Frederick M. Cohan

Frederick M. Cohan

No abstract provided.


Cyanobacterial Ecotypes In The Microbial Mat Community Of Mushroom Spring (Yellowstone National Park, Wyoming) As Species-Like Units Linking Microbial Community Composition, Structure And Function, D. M. Ward, M. M. Bateson, M. J. Ferris, M. Kuhl, A. Wieland, A. Koeppel, Frederick M. Cohan Dec 2005

Cyanobacterial Ecotypes In The Microbial Mat Community Of Mushroom Spring (Yellowstone National Park, Wyoming) As Species-Like Units Linking Microbial Community Composition, Structure And Function, D. M. Ward, M. M. Bateson, M. J. Ferris, M. Kuhl, A. Wieland, A. Koeppel, Frederick M. Cohan

Frederick M. Cohan

No abstract provided.


Soluble Fibrin Inhibits Monocyte Adherence And Cytotoxicity Against Tumor Cells: Implications For Cancer Metastasis, John Biggerstaff, Brandy Weidow, Jacqueline Vidosh, Judith Dexheimer, Shonak Patel, Pretesh Patel Dec 2005

Soluble Fibrin Inhibits Monocyte Adherence And Cytotoxicity Against Tumor Cells: Implications For Cancer Metastasis, John Biggerstaff, Brandy Weidow, Jacqueline Vidosh, Judith Dexheimer, Shonak Patel, Pretesh Patel

John Biggerstaff

Background Soluble fibrin (sFn) is a marker for disseminated intravascular coagulation and may have prognostic significance, especially in metastasis. However, a role for sFn in the etiology of metastatic cancer growth has not been extensively studied. We have reported that sFn cross-linked platelet binding to tumor cells via the major platelet fibrin receptor αIIbβ3, and tumor cell CD54 (ICAM-1), which is the receptor for two of the leukocyte β2 integrins (αLβ2 and aMβ2). We hypothesized that sFn may also affect leukocyte adherence, recognition, and killing of tumor cells. Furthermore, in a rat experimental metastasis model sFn pre-treatment of tumor cells ...


Absence Of Spiroplasma Or Other Bacterial 16s Rrna Genes In Brain Tissue Of Hamsters With Scrapie, Irina Alexeeva, Ellen J. Elliott, Sandra Rollins, Gail E. Gasparich, Jozef Lazar, Robert G. Rohwer Dec 2005

Absence Of Spiroplasma Or Other Bacterial 16s Rrna Genes In Brain Tissue Of Hamsters With Scrapie, Irina Alexeeva, Ellen J. Elliott, Sandra Rollins, Gail E. Gasparich, Jozef Lazar, Robert G. Rohwer

Gail Gasparich

Spiroplasma spp. have been proposed to be the etiological agents of the transmissible spongiform encephalopathies (TSEs). In a blind study, a panel of 20 DNA samples was prepared from the brains of uninfected hamsters or hamsters infected with the 263K strain of scrapie. The brains of the infected hamsters contained ≥1010 infectious doses/g. The coded panel was searched for bacterial 16S rRNA gene sequences, using primers selective for spiroplasma sequences, primers selective for mollicutes in general, and universal bacterial primers. After 35 PCR cycles, no samples were positive for spiroplasma or any other bacterial DNA, while control Spiroplasma mirum ...