Search

The role of periplasmic disulfide oxidoreductase DsbA in Shiga toxin-producing Escherichia coli O157:H7 (STEC) was investigated. Deletion of dsbA (Δ dsbA) significantly decreased cell motility and alkaline phosphatase activity in STEC. STEC Δ dsbA also showed greater sensitivity to menadione and under low pH conditions. Significant reductions in surface attachment to both biotic (HT-29 epithelial cells) and abiotic (polystyrene and polyvinyl chloride) surfaces were observed in STEC Δ dsbA. In addition, no biofilm formation was detected in STEC Δ dsbA compared to wild-type cells in glass capillary tubes under continuous flow-culture system conditions. In the nematode model Caenorhabditis elegans-killing assay, the deletion of dsbA in STEC resulted in attenuated virulence compared to wild-type cells. STEC Δ dsbA was also found to have a reduced ability to colonize the nematode gut. These results suggest that DsbA plays important roles in biofilm formation and virulence in STEC cells. [ABSTRACT FROM AUTHOR]

The article reports on the results of a study of the expression and functions of serum amyloid A (SAA) isoforms during apoptosis of HC11 mammary gland epithelial cells. A description of the experimental set-up and measurement methods is presented. The study concluded that the induction of SAA genes is associated with growth and apoptosis of HC11 mammary epithelial cells.

One strain of Lactobacillus salivarius, two strains of Lactobacillus reuteri and Lactobacillus amylovorus, and two strains of Bifidobacterium thermacidophilum with antagonistic effect against Clostridium perfringens were isolated from porcine gastrointestinal tract. Isolates were assayed for their ability to survive in synthetic gastric juice at pH 2.5 and were examined for their ability to grow on agar plate containing porcine bile extract. There was a large variation in the survival of the isolates in gastric juice and growth in the medium containing 0.3% ( w/ v) bile. L. salivarius G11 and L. amylovorus S6 adhered to the HT-29 epithelial cell line. Cell-free supernatant of L. amylovorus S6 showed higher antagonistic activity as effective as the antibiotics such as neomycin, chlortetracycline, and oxytetracycline against bacterial pathogens including C. perfringens, Salmonella typhimurium, Staphylococcus aureus, Vibrio cholerae, Edwardsiella tarda, and Aeromonas salmonicida subsp. salmonicida. [ABSTRACT FROM AUTHOR]