Degradative enzymes of oral streptococci

Members of the Streptococcus sanguis group (SSG) and Streptococcus milleri group (SMG) were screened for their ability to produce glycosidase, arylamidase (peptidase), protease, dextranase and glycosyltransferase activities. Species within each group produced unique patterns of activity. The most commonly produced glycosidases were β-D-glucosidase, β-D- galactosidase, N-acetyl-β-D-glucosaminidase and N-acetyl-β-D-galactosaminidase and the least commonly produced glycosidase activity was β-fucosidase with Streptococcus intermedius (SMG) being the only species capable of producing the activity. For arylamidase activity, the most commonly produced type was lysine-arylamidase. Glycosidase and arylamidase activities were localized to particular sub-cellular fractions. α-galactosidase was found only in culture supernatant fluids whereas N-acetyl-β-D-glucosaminidase was found in all fractions; the culture supernatant, cell wall, cell membrane and cytoplasm. No arylamidase activity was seen in culture supernatants. Phe-arg-arylamidase was found only in cytoplasmic fractions whereas val-pro-arg-arylamidase was found in cell walls, cell membranes and cytoplasmic fraction. Protease activity was measured as the degradation of bovine serum albumin (BSA) and casein. Casein was degraded by a number of strains whereas no species/strains were able to degrade BSA. Streptococcus intermedius, Streptococcus constellates (SMG), Streptococcus mitior and Streptococcus defectivus (SSG) were the only species that produced hyaluronidase and no species produced chondroitin sulphatase. The groups were also examined for their abilities to produce glycosyltransferase and dextranase. Strep. sanguis, Streptococcus gordonii, Streptococcus mitis and Streptococcus oralis produced glucosyltransferase and, with the exception of the latter species, fructosyl-transferase. No species within the SMG was capable of producing either glycosyltransferase. No species within the SSG or SMG was able to produce dextranase activity. The ability of species to produce different types of enzymes was related to their taxonomy, allowing the differentiation of several new taxonomic types within the SSG and may be related to pathogenesis.     

Antigenic variation among Borrelia spp. in relapsing fever.

Seven antigens of Borrelia hermsii, B. parkeri, and B. turicatae with isoelectric points in the range of 4.4 to 5.0 and molecular masses of 40 to 43 kilodaltons played a role in the relapse phenomenon of relapsing fever. Based upon location of the antigens in the outer envelope, the molecular weight, and Western blot analysis, the antigens from each phase of spirochetemia appeared to be a mixture of the serotype-specific antigens of cloned B. hermsii.     

Pasteurella multocida Type I: The Antigens of • I. Capsular Polysaccharides

Dried cells of Pasteurella multocida type I were extracted with 2.5 per cent aqueous solution of sodium chloride. Acidification of the extract with HCl to pH 3.8 yielded a fraction containing protein with some polysaccharide and lipopolysaccharide. This was removed by centrifugation. Addition of ethanol to the supernatant precipitated a polysaccharide containing fructose, mannose, glucose and glucosamine. This polysaccharide could be further fractionated into products containing varying proportions of glucosamine and fructose. It is produced by both `blue' non-capsulated and `fluorescent' capsulated phases of the same strains. From the former it is almost entirely released into the surrounding medium instead of remaining bound to the surface layers of the bacteria. The purified (heterogeneous) polysaccharide fraction is precipitable and fixes complement with homologous sera. When added in repeated amounts to rabbit and cattle sera against whole bacteria until no further precipitate formed it reduced but did not abolish the mouse-protective power of the sera. It did not immunize mice to challenge when injected subcutaneously or intraperitoneally in doses ranging from 2 to 100 μg.     

Serological studies on chemostat-grown cultures of Lactobacillus fermentum and Lactobacillus plantarum.

Lactobacillus fermentum NCTC 6991 and Lactobacillus plantarum NCIB 7220 were grown in a chemostat in the diffusible fraction of complex medium at pH 6.0 with glucose limitation. Organisms grown at different dilution rates (D) were injected into rabbits, and the resultant antisera were examined for reactivity with antigens previously isolated from batch-grown organisms. For L. fermentum, antisera obtained on injecting cells grown at D = 0.5 h-1 contained a significantly higher level of antibody reacting with lipoteichoic acid and a lower level of antibody reacting with wall polysaccharide than did antisera obtained with slower-growing cells (D = 0.05 and 0.033). Antibodies to the cell wall polysaccharide were alpha-D-glucosyl specific and cross-reacted with dextran and alpha-D-glucosyl ribitol teichoic acid from L. plantarum. The immunogenicity of the ribitol teichoic acid and lipoteichoic acid components of L. plantarum was not influenced by injecting organisms grown at different rates. However, chemical and serological studies indicate that growth of L. plantarum in the diffusible fraction of complex medium results in a wall teichoic acid of lower glucose substitution. This apparently influences the specificity of the resultant antibodies so that some sera react much less with glucosyl-substituted lipoteichoic acid and dextran.     

Influence of growth conditions on adherence of Streptococcus mutans ingbritt to saliva-coated hydroxyapatite.

Streptococcus mutans Ingbritt grown under standardized conditions adhered less effectively to saliva-coated hydroxyapatite beads than did Streptococcus sanguis G9B, and there was competition for binding. The results with Ingbritt were influenced by the generation time, the pH of growth, and the carbohydrate source as shown by studies on organisms grown in continuous culture.     

Clonal chromosome abnormalities in human breast carcinomas I. Twenty-eight cases with primary disease

Cytogenetic analysis was performed on a selected series of short-term cultures of primary breast carcinomas from 28 patients. All patients had histopathologically confirmed malignancies, with the majority (25/28 cases) demonstrating infiltrating ductal carcinoma. All 28 cases evidenced clonal chromosome abnormalities, with 10/28 displaying only numeric aberrations, whereas 18/28 displayed clonal structural alterations. In near-diploid tumors the most common numeric changes were — 17 and — 19. However, trisomy 7 was the only numeric change in two near-diploid tumors. Structural chromosome alterations were primarily isochromosomes, apparent terminal deletions, and unbalanced non-reciprocal translocations. Chromosomes 1 (10/18–56%) and 6 (8/18–44%) were most frequently altered in this series. Breakpoints of clonal structural abnormalities were shown to cluster to several chromosome segments, including 1p22-q11, 3p11, 6p11–13, 7p11-q11, 8p11-q11, and 19q13. Analysis of the gain or loss of specific chromosome segments revealed that the most consistent tendency was over-representation of 1q, 3q, and 6p. © 1993 Wiley-Liss, Inc.     

Immunodetection methods for grass pollen allergens on western blots

A comparison is made of eight different methods to detect allergenic proteins in Western blots of rye-grass pollen extracts. Horseradish peroxidase-based enhanced chemiluminescence (ECL) provides a sensitive method for the detection of allergenic proteins. The method has been modified to use more dilute solutions of ECL substrate to reduce the background, can be applied to a standard nitrocellulose membrane, and used with Kodak X-ray film. The assays can be performed rapidly, replacing use of radiolabelled probes. Increased resolution is obtained. This makes the method suitable for detection of cDNA clones on plaque lifts, and for rapid and specific purification of proteins following immunodetection on nitrocellulose membranes.