Studies on Group Antigens of Lactobacillus casei

Abstract

Members of the genus Lactobacillus were classified serologically into several groups by the extensive studies of Sharpe [12][13][14]. She showed that serological specificities were determined by the carbohydrate moiety of the bacterial cells and that L. casei strains were divided into group B and group C.Immunochemical investigations on the specific antigens of groups B and C were carried out by Knox and his coworkers [3][4][5][6][7][8].The group-specific antigens were identified as polysaccharide components of the bacterial cell walls, and the probable configurations of the determinant sites were also presented.However, in addition to these groupspecific antigens, antigens common to both groups were also anticipated, because strong cross reactions were recognized in precipitin reactions using Sharpe's antigens.In our experiments more precise antigenic analyses of L. casei were carried out and some new findings were obtained. MATERIALS AND METHODSOrganisms. Bacterial strains used in the experiments are listed in Table 1. Five strains were kindly supplied by Dr. M. E. Sharpe, National Institute for Research in Dairying, Reading, England, and eight strains were from Dr. T. Mitsuoka, Institute of Physical and Chemical Research, Tokyo, Japan. Remaining four strains were isolated and maintained in our laboratory. Serological classifications into group B or C were carried out by the Sharpe method [12].Preparation of cell walls. Cells grown in the MRS medium [2] for 18 to 24 hr at 37 C were centrifuged at 8000 rpm for 15 min and washed twice with saline. The washed cells were disrupted by grinding with synthetic Zeolite type 4A as described by Wistreich et al [15]. The crude cell walls thus obtained were treated with trypsin and ribonuclease according to the method of Cummins and Harris [1], and washed thoroughly with distilled water.

Antigenic Analyses of Lactobacillus fermenti

“…Furthermore, a single identical precipitin band was formed by the reactions between anti-137 serum and extracts of strains 145, 593 and 137, and the antigen causing the band was designated as antigen 8. All of these extracts reacted with the antiserum against strain C-5 of L. casei (group C) with an identical pattern to antigen 3 which had been previously described [16]. Table 2 shows the results for extracts of other strains and their origins.…”

“…The antigenic determinant isolated from the intracellular membrane of Lactobacillus casei NIRD RO-94 was identified as glycerol teichoic acid. Independent of their findings, we [16] also demonstrated the presence of common antigen 3 in whole cells of lactobacilli and staphylococci giving positive results with the immunodiffusion method using antiserum against strain C-5 (NIRD RO-94) which was also used by Sharpe et al [13].…”

“…Antigens were extracted from whole cells or cell walls with 10% cold trichloroacetic acid (TCA) as previously described by the authors [16] and also with 0.05 N HCl from whole cells according to Sharpe [11]. Four volumes of cold ethanol were added to these extracts and the mixtures were kept in the cold.…”

“…Preparation and absorption of antisera. Antisera were prepared by intravenous injections of bacteria into rabbits and their absorptions were carried out as previously described [16].…”

Production of Starch with Antioxidative Activity by Baking Starch with Organic Acids

“…Caramel is a brown material generated when sugar is heated to approximately 150 C, 7) and it has been reported that caramel had antioxidative potential and a strong positive correlation with the extent of coloring in its DPPH radical scavenging ability. 8,9) The formation of caramel in this study was expected by processing starch at high temperature with organic acids. It is inferred from these results and previous reports that a large proportion of the products formed by mixing and baking starch with phytic acid was caramel.…”