Search Results - (Author, Cooperation:S. N. Wai)

2018-02-15

Nature Publishing Group (NPG)

2041-1723

Biology

Chemistry and Pharmacology

Natural Sciences in General

Physics

2013-04-05

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Anti-Bacterial Agents/*metabolism ; *Antibiosis ; *Bacterial Secretion Systems ; Cell Membrane/chemistry/metabolism ; Evolution, Molecular ; Phosphatidylethanolamines/metabolism ; Phospholipase D/chemistry/classification/*metabolism ; Phylogeny ; Pseudomonas aeruginosa/*enzymology/metabolism/pathogenicity ; Species Specificity ; Substrate Specificity ; Virulence Factors/chemistry/metabolism

1432-072X

Key wordsCampylobacter jejuni ; Iron-containing ; protein ; Ferritin

Springer Online Journal Archives 1860-2000

Biology

Abstract We purified an iron-containing protein from Campylobacter jejuni using ultracentrifugation and ion-exchange chromatography. Electron microscopy of this protein revealed circular particles with a diameter of 11.5 nm and a central core with a diameter of 5.5 nm. The protein was composed of a single peptide of 21 kDa and did not serologically cross-react with horse spleen ferritin. The UV-visible spectrum of the protein showed no absorption peaks in the visible region, indicating that little or no heme is bound. The ratio of Fe:phosphate of C. jejuni ferritin was 1.5:1. From these morphological and chemical examinations, we concluded that the C. jejuni purified protein is a ferritin of the same class as that of Helicobacter pylori and Bacteroides fragilis and differs from the heme-containing bacterioferritin of Escherichia coli. The 30 N-terminal amino acids were sequenced and were found to resemble the sequences of other ferritins strongly (H. pylori ferritin, 73% identity; B. fragilis ferritin, 50% identity; E. coli gene-165 product, 50% identity), and to a lesser degree, bacterioferritins (E. coli bacterioferritin, 26% identity; Azotobacter vinelandii, 26% identity; horse spleen ferritin 30% identity). Proteins that cross-reacted with antiserum against the ferritin of C. jejuni were found in other Campylobacter species and in H. pylori, but not in Vibrio, E. coli, or Pseudomonas aeruginosa.

Electronic Resource

1432-072X

Key wordsEscherichia coli O157 ; Nonculturable ; cells ; Restoration of culturability ; H2O2-degrading ; compounds

Springer Online Journal Archives 1860-2000

Biology

Abstract Late-exponential-phase cells of Escherichia coli O157:H- strain E32511/HSC became nonculturable in sterilized distilled water microcosms at 4 °C. Plate counts declined from 3 × 106 to less than 0.1 CFU/ml in about 21 days. However, when samples of microcosms at 21 days were inoculated onto an agar medium amended with catalase or nonenzyme peroxide-degrading compounds such as sodium pyruvate or α-ketoglutaric acid, plate counts increased to 104–105 CFU/ml within 48 h. The proposed mode of action of the catalase or pyruvate is via the degradation of the metabolic by-product H2O2, rather than through supplementation of a required nutrient in the recovery of nonculturable cells. Our studies were based on the assumption that E32511/HSC strain responds to starvation and a low temperature by entering a nonculturable state and that the correction of oxidative stress upon the inoculation of bacteria on agar plates promotes recovery of nonculturable cells.

Electronic Resource