Genetic and molecular characterization of pR351 plasmid from enteropathogenic Escherichia coli strain.

A pR351 plasmid (Tc Ap Cb) conferring drug resistance of naturally occurring E. coli strain was examined. Conjugation and transduction experiments have indicated that this plasmid is R plasmid aggregate consisting of three independent plasmids: a) conjugative plasmid pR351 A (SuTc) fi- (F) belonging to incompatibility group L, b) conjugative plasmid pR351 B (SuApCb) fi- (F) belonging to incompatibility O, and c) non-conjugative plasmid pR351 C (ApCb).

Effect of slime extract from Pseudomonas aeruginosa on cell mediated immunity induced in mice by Salmonella typhimurium.

Immunity of mice intraperitoneally treated with slime extract and 24 h later intravenously immunized with live Salmonella typhimurium cells, was studied. The induced immunity was evaluated by determining the number of bacteria in the spleens and mortality of the animals. Slime extract in the dose of 200 micrograms/mice was found to suppress the immunity which manifested itself by enhanced proliferation of bacterial in the spleens and increased mortality as compared to control animals.

Nonopsonic phagocytosis and intracellular killing of Salmonella typhimurium by peritoneal macrophages of mice immunized with slime-extract from Pseudomonas aeruginosa.

Treatment of mice with slime-extract (SE) from Pseudomonas aeruginosa strain 219 failed to increase the proportion of ingested cells of Salmonella typhimurium by immune macrophages (M phi) of mice. However, activated with SE peritoneal SE peritoneal M phi displayed the enhancement of their nonspecific bactericidal activity. It has been found that immune M phi, depending on the dose of SE used for vaccination, killed intracellularly 38 to 67% of bacterial cells, whereas the mean value for the bactericidal capacity of normal resident phagocytes was 7%.

Depression by slime-extract from Pseudomonas aeruginosa of delayed type hypersensitivity to sheep erythrocytes.

High doses of slime-extract from Pseudomonas aeruginosa was found to suppress the delayed type hypersensitivity response to sheep erythrocytes when administered intraperitoneally 1 to 3 days before or 3 days after intravenous sensitization of mice. Moreover, the spleen cells from sensitized and slime-extract treated mice transferred the depression to normal recipients. Inhibition of DTH response was also seen when recipients were injected with slime-extract 24 h before they were infused with spleen cells from donor mice immunized with sheep erythrocytes.

Phagocytosis and intracellular killing of Pseudomonas aeruginosa by peritoneal macrophages of mice.

The poorly mucoid P. aeruginosa 87 strain was better phagocytized by peritoneal macrophages from normal mice than highly mucoid P. aeruginosa 219.