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Genetics

Microbiology

2005

Articles 1 - 4 of 4

Full-Text Articles in Life Sciences

Sara Positively Controls Bap-Dependent Biofilm Formation In Staphylococcus Aureus, María P. Trotonda, Adhar C. Manna, Ambrose L. Cheung, Iñigo Lasa, José R. Penadés Aug 2005

Sara Positively Controls Bap-Dependent Biofilm Formation In Staphylococcus Aureus, María P. Trotonda, Adhar C. Manna, Ambrose L. Cheung, Iñigo Lasa, José R. Penadés

Dartmouth Scholarship

The biofilm-associated protein Bap is a staphylococcal surface protein involved in biofilm formation. We investigated the influence of the global regulatory locus sarA on bap expression and Bap-dependent biofilm formation in three unrelated Staphylococcus aureus strains. The results showed that Bap-dependent biofilm formation was diminished in the sarA mutants by an agr-independent mechanism. Complementation studies using a sarA clone confirmed that the defect in biofilm formation was due to the sarA mutation. As expected, the diminished capacity to form biofilms in the sarA mutants correlated with the decreased presence of Bap in the bacterial surface. Using transcriptional fusion and …


Integrated Recombinant Protein Expression And Purification Platform Based On Ralstonia Eutropha, Gavin C. Barnard, Jesse D. Mccool, David W. Wood, Tillman U. Gerngross May 2005

Integrated Recombinant Protein Expression And Purification Platform Based On Ralstonia Eutropha, Gavin C. Barnard, Jesse D. Mccool, David W. Wood, Tillman U. Gerngross

Dartmouth Scholarship

Protein purification of recombinant proteins constitutes a significant cost of biomanufacturing and various efforts have been directed at developing more efficient purification methods. We describe a protein purification scheme wherein Ralstonia eutropha is used to produce its own “affinity matrix,” thereby eliminating the need for external chromatographic purification steps. This approach is based on the specific interaction of phasin proteins with granules of the intracellular polymer poly


Sara Is An Essential Positive Regulator Of Staphylococcus Epidermidis Biofilm Development, Maria A. Tormo, Miguel Marti, Jaione Valle, Adhar C. Manna Apr 2005

Sara Is An Essential Positive Regulator Of Staphylococcus Epidermidis Biofilm Development, Maria A. Tormo, Miguel Marti, Jaione Valle, Adhar C. Manna

Dartmouth Scholarship

Staphylococcus epidermidis biofilm formation is associated with the production of the polysaccharide intercellular adhesin (PIA)--poly-N-acetylglucosamine polysaccharide (PNAG) by the products of the icaADBC operon. Recent evidence indicates that SarA, a central regulatory element that controls the production of Staphylococcus aureus virulence factors, is essential for the synthesis of PIA/PNAG and the ensuing biofilm development in this species. Based on the presence of a sarA homolog, we hypothesized that SarA could also be involved in the regulation of the biofilm formation process in S. epidermidis. To investigate this, we constructed nonpolar sarA deletions in two genetically unrelated S. epidermidis clinical strains, …


A Three-Component Regulatory System Regulates Biofilm Maturation And Type Iii Secretion In Pseudomonas Aeruginosa, Sherry L. Kuchma, John P. Connolly, George A. O'Toole Feb 2005

A Three-Component Regulatory System Regulates Biofilm Maturation And Type Iii Secretion In Pseudomonas Aeruginosa, Sherry L. Kuchma, John P. Connolly, George A. O'Toole

Dartmouth Scholarship

Biofilms are structured communities found associated with a wide range of surfaces. Here we report the identification of a three-component regulatory system required for biofilm maturation by Pseudomonas aeruginosa strain PA14. A transposon mutation that altered biofilm formation in a 96-well dish assay originally defined this locus, which is comprised of genes for a putative sensor histidine kinase and two response regulators and has been designated sadARS. Nonpolar mutations in any of the sadARS genes result in biofilms with an altered mature structure but do not confer defects in growth or early biofilm formation, swimming, or twitching motility. After …