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Microbiology

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Selected Works

2007

Articles 1 - 5 of 5

Full-Text Articles in Life Sciences

Influence Of The Hydrodynamic Environment On Quorum Sensing In Pseudomonas Aeruginosa Biofilms, Jeffrey J. Margolis, Mary Jo Kirisits, Boloroo L. Purevdorj-Gage, Benjamin Vaughan, David L. Chopp, Paul Stoodley, Matthew R. Parsek Oct 2007

Influence Of The Hydrodynamic Environment On Quorum Sensing In Pseudomonas Aeruginosa Biofilms, Jeffrey J. Margolis, Mary Jo Kirisits, Boloroo L. Purevdorj-Gage, Benjamin Vaughan, David L. Chopp, Paul Stoodley, Matthew R. Parsek

Jeffrey Margolis

We provide experimental and modeling evidence that the hydrodynamic environment can impact quorum
sensing (QS) in a <em>Pseudomonas aeruginosa</em> biofilm. The amount of biofilm biomass required for full QS induction of the population increased as the flow rate increased.

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Molecular Genetics And Genomic Analysis Of Scytonemin Biosynthesis In Nostoc Punctiforme Atcc 29133, Tanya Soule, Valerie Stout, Wesley Swingley, J C. Meeks, Ferran Garcia-Pichel May 2007

Molecular Genetics And Genomic Analysis Of Scytonemin Biosynthesis In Nostoc Punctiforme Atcc 29133, Tanya Soule, Valerie Stout, Wesley Swingley, J C. Meeks, Ferran Garcia-Pichel

Tanya Soule

The indole-alkaloid scytonemin is the most common and widespread sunscreen among cyanobacteria. Previous research has focused on its nature, distribution, ecology, physiology, and biochemistry, but its molecular genetics have not been explored. In this study, a scytonemin-deficient mutant of the cyanobacterium Nostoc punctiforme ATCC 29133 was obtained by random transposon insertion into open reading frame NpR1273. The absence of scytonemin under conditions of induction by UV irradiation was the single phenotypic difference detected in a comparative analysis of the wild type and the mutant. A cause-effect relationship between the phenotype and the mutation in NpR1273 was demonstrated by constructing a …

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In Vivo Negative Selection Screen Identifies Genes Required For Francisella Virulence, David S. Weiss, Anna Brotcke, Thomas Henry, Jeffrey J. Margolis, Kaman Chan, Denise M. Monack Apr 2007

In Vivo Negative Selection Screen Identifies Genes Required For Francisella Virulence, David S. Weiss, Anna Brotcke, Thomas Henry, Jeffrey J. Margolis, Kaman Chan, Denise M. Monack

Jeffrey Margolis

<em>Francisella tularensis</em> subverts the immune system to rapidly grow within mammalian hosts, often causing tularemia, a fatal disease. This pathogen targets the cytosol of macrophages where it replicates by using the genes encoded in the <em>Francisella</em> pathogenicity island. However, the bacteria are recognized in the cytosol by the host’s ASC/caspase-1 pathway, which is essential for host defense, and leads to macrophage cell death and proinflammatory cytokine production. We used a microarray-based negative selection screen to identify <em>Francisella</em> genes that contribute to growth and/or survival in mice. The screen identified many known virulence factors including all of the Francisella pathogenicity island …

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Genetic Diversity And Potential Function Of Microbial Symbionts Associated With Newly Discovered Species Of Osedax Polychaete Worms, Shana K. Goffredi, Shannon B. Johnson, Robert C. Vrijenhoek Mar 2007

Genetic Diversity And Potential Function Of Microbial Symbionts Associated With Newly Discovered Species Of Osedax Polychaete Worms, Shana K. Goffredi, Shannon B. Johnson, Robert C. Vrijenhoek

Shana Goffredi

We investigated the genetic diversity of symbiotic bacteria associated with two newly discovered species of Osedax from Monterey Canyon, CA, at 1,017-m (Osedax Monterey Bay sp. 3 “rosy” [Osedax sp. MB3]) and 381-m (Osedax Monterey Bay sp. 4 “yellow collar”) depths. Quantitative PCR and clone libraries of 16S rRNA gene sequences identified differences in the compositions and abundances of bacterial phylotypes associated with the newly discovered host species and permitted comparisons between adult Osedax frankpressi and juveniles that had recently colonized whalebones implanted at 2,891 m. The newly discovered Osedax species hosted Oceanospirillales symbionts that are related to Gammaproteobacteria associated …

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In The Heat Of The Law, It's Not Just Steam: Geothermal Resources And The Impact On Thermophile Biodiversity, Donald J. Kochan, Tiffany Grant Dec 2006

In The Heat Of The Law, It's Not Just Steam: Geothermal Resources And The Impact On Thermophile Biodiversity, Donald J. Kochan, Tiffany Grant

Donald J. Kochan

Significant research has been conducted into the utilization of geothermal resources as a ‘green’ energy source. However, minimal research has been conducted into geothermal resource utilization and depletion impacts on thermophile biodiversity. Thermophiles are organisms which have adapted over millions of year to extreme temperature and chemical compositions and exist in hot springs and other geothermal resources. Their ability to withstand high temperatures makes them invaluable to scientific and medical research. Current federal and California case law classify geothermal resources as a mineral, not a water resource. Acquisition of rights to develop a geothermal resource owned or reserved by the …

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