Immunoglobulin A proteases in gram-negative bacteria isolated from human urinary tract infections.

Several strains of gram-negative bacteria (seven genera, eight species) isolated from patients with urinary tract infections were found to hydrolyze myeloma immunoglobulin A (IgA) protein. Human IgG and IgM and colostrum IgA were not degraded by these organisms. Examination of cleavage digests showed two fragments of different electrophoretic mobilities, with antigenic reactivity and sodium dodecyl sulfate polyacrylamide gel electrophoresis profiles consistent with their identification as Fc and Fab components. The immunoelectrophoresis patterns of cleavage digests suggested that the proteases responsible for this hydrolysis may be dissimilar in the specificity of their IgA cleavage sites.

Spontaneous release of lipopolysaccharide by Pseudomonas aeruginosa.

Pseudomonas aeruginosa PAO grown in glucose mineral salts medium released lipopolysaccharide which was chemically and immunologically similar to the cellular lipopolysaccharide. In addition, it possessed identical phage E79-inactivating properties. Through neutralization of phage activity and hemolysis inhibition assays, the organism was found to liberate lipopolysaccharide at a constant rate during log-phase growth equivalent to 1.3 to 2.2 ng/10(8) cells over a growth temperature range of 25 to 42 degrees C. At 19 degrees C, a lipopolysaccharide was released which was deficient in phage-inactivating activity but retained its immunological properties. Chemical analysis of lipopolysaccharide extracted from cells grown at 19 degrees C showed a deficiency in the O-side-chain component fucosamine. Gel exclusion chromatography of the polysaccharide fraction derived from lipopolysaccharide isolated from cells grown at 19 degrees C exhibited a decreased content of side-chain polysaccharide as well as a difference in the hexosamine:hexose ratio. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis confirmed these results as well as establishing that an essentially normal distribution of side-chain repeating unit lengths were to be found in the 19 degrees C preparation. These results suggest a decrease in the frequency of capping R-form lipopolysaccharide at 19 degrees C.

Arylsulfatase in Salmonella typhimurium: detection and influence of carbon source and tyramine on its synthesis.

Arylsulfatase synthesis was shown to occur in Salmonella typhimurium LT2. The enzyme had a molecular weight of approximately 50,000 and was separated into five forms by isoelectrofocusing. The optimal pH for substrate hydrolysis was pH 6.7, with Michaelis constants for nitrocatechol sulfate and nitrophenyl sulfate being 4.1 and 7.9 mM, respectively. Enzyme synthesis was strongly influenced by the presence of tyramine in the growth medium. The uptake of [14C]tyramine and arylsulfatase synthesis were initiated during the second phase of a diauxie growth response, when the organism was cultured with different carbon sources. Adenosine 3',5'-cyclic monophosphoric acid enhanced the uptake of tyramine and the levels of arylsulfatase synthesized. However, the addition of glucose and glycerol to organisms actively transporting tyramine and synthesizing enzyme caused a rapid inhibition of both of these processes. This inhibition was not reversed by adding adenosine 3',5'-cyclic monophosphoric acid. The results suggest that the effect of the carbon source on tyramine transport and arylsulfatase synthesis may be explained in terms of inducer exclusion.

The extraction and analysis of lipopolysaccharides from Pseudomonas aeruginosa strain PAO, and three rough mutants.

Three spontaneously arising rough mutants of Pseudomonas aeruginosa have been isolated by selection for resistance to virulent lipopolysaccharide (LPS) specific bacteriophages. In addition, the first phages specific for rough mutants of P. aeruginosa were isolated. Using these phage and autoagglutination patterns in 4% NaCl and acriflavine, these mutants could be clearly distinguished from the wild-type strain and each other. Chemical analysis of the LPS together with chromatographic resolution of the polysaccharide moieties showed alterations in both O-specific side chains and core regions.

Susceptibility of lipopolysaccharide-defective mutants of Pseudomonas aeruginosa strain PAO to dyes, detergents, and antibiotics.

Lipopolysaccharide-defective mutants of Pseudomonas aeruginosa strain PAO have been isolated on the basis of their resistance to lipopolysaccharide-specific bacteriophages. These mutants have been differentiated by their agglutination in NaCl and acriflavine, phage sensitivity, and chemical analysis of the lipopolysaccharides. The susceptibility of the wild-type strain and four mutants to a series of twenty-six agents, including dyes, detergents, antibiotics, and lysozyme, was examined. The roughest mutant (AK-43) exhibited increased susceptibility to sodium deoxycholate, hexadecylpyridinium chloride, benzalkonium chloride, ampicillin, penicillin G, erythromycin, colymycin, and polymyxin B. The role of cell envelope fractions in antibiotic resistance in P. aeruginosa is discussed.

The nature of Pseudomonas aeruginosa strain PAO bacteriophage receptors.

Receptors for phages specific to Pseudomonas aeruginosa strain PAO were studied. Phages 16, 44, 109, F8, and PBI are lipopolysaccharide (LPS) specific as shown by neutralization tests. The PhI50's of the LPS, adsorption rate constants with strain PAO and the plaque morphologies of these five phages were quite similar. Phages 1214 and 7 also appear to be LPS-specific on the basis of host-range studies. Phage 73 is pilus-specific, while phages 21 and 68 fall into a group which does not attach to pili, flagella, or LPS. A theoretical approach to the interpretation of phage-cell interactions is presented.

Pseudomonas aeruginosa lipopolysaccharide: factors influencing toxicity for isolated mitochondria and endotoxin properties.

In the present study Pseudomonas aeruginosa lipopolysaccharide (LPS) exhibited the following endotoxin properties: (1) toxicity for mice; (2) gelation of the Limulus lysate; (3) induction of a localized Shwartzman reaction in the skin of rabbits, and (4) anticomplementary activity. Differences in LPS toxicity as measured with the rat liver mitochondrial assay system were found to be related to the nature of the bacterial growth media, the functional integrity of mitochondria, and the time and temperature of mitochondrial assay. The significance of these findings to P. aeruginosa infections is discussed, and it is concluded that LPS is a factor of importance.

Pseudomonas aeruginosa lipopolysaccharide: an uncoupler of mitochondrial oxidative phosphorylation.

The addition of Pseudomonas aeruginosa KCIIR LPS to respiring mitochondria stimulated the rate of substrate oxidation, reduced the respiratory control ratio, stimulated oxygen uptake in state 4, and released the inhibition imposed upon state 3 by atractyloside. It was concluded that LPS acted as an uncoupler of oxidative phosphorylation and that it produced effects similar to those observed with the classical uncoupler 2,4-dinitrophenol.