A survey of Vibrio cholerae non-O1 from surface water and sediment samples was carried out in the aquatic environment of Hiroshima City. Of 72 water samples, 49 (68.1%) were positive for the organism, while in sediment samples 17 of 47 (36.2%) were positive. The incidence of the organism was higher in summer than in other seasons in both water and sediment samples. Isolation frequency of V. cholerae non-O1 was independent of other marine vibrios. Salinity and pH did not have an obvious influence on the distribution of this organism. All the isolates were hemolytic on sheep blood agar, and quantitative analysis revealed a high potential of hemolysin production of more than 1, 000 hemolytic units in 10 of 130 strains tested. A large number of isolates (60/102) were cytotoxigenic on CHO cell culture. Various cytopathic effects were displayed, including cytolytic, cell elongation, and a combination of these. All the isolates were incapable of producing any detectable cholera-like enterotoxin. These findings suggest that V. cholerae non-O1 is widespread in and around the Hiroshima City aquatic environment throughout the year and possesses the ability to cause infection.
Gram-positive and catalase-positive cocci isolated from fermented fish and soy sauce mash were systematically studied based on phenotypic and chemotaxonomic characteristics. They were separated into 2 groups (A and B) by photobiotin labeling DNA-DNA hybridization. Of 18 isolates studied, 10 (Group A) showed DNA homologies of more than 69% compared to the type strain of Staphylococcus carnosus and were identified as S. carnosus. Eight isolates (Group B) showed DNA homologies of less than 50% compared to the type strain of S. carnosus and no relatedness to the reference strains of Staphylococcus species. The DNA base composition of these two groups ranged from 34.4 to 37.3mol% of guanine plus cytosine. They contained MK-7 as a major menaquinone and MK-6 or MK-6 and MK-8 as minor menaquinones, and the tested strains had anteiso-C15:0 as a major fatty acid. Detailed characteristics of S. carnosus were described.
With the aim of elucidating the immunizing ability of plant-growth-affecting rhizosphere pseudomonads, seeds of a susceptible bean (Phaseolusvulgaris L) cv. Bonita, were subjected to bacterization before challenging with the halo blight bacterial pathogen Pseudomonas syringae pv. phaseolicola. In the greenhouse, induced systemic resistance to halo blight was found in bean plants treated with a plant growth stimulatory strain of P. fluorescens (S 97), whereas deleterious pseudomonads MA 250 and VS 50 were found to induce susceptibility towards the disease. Immunization ability of S 97 was reduced at low inoculum densities (<107 live cells per ml) or eliminated when the suspension was autoclaved. The maximum disease protection, measured in terms of number of halo blight lesions in trifoliate leaves, was obtained at the highest inoculum concentration (108 live cells per ml). Agar diffusion assay in vitro revealed that S 97 exhibits bacteriostatic activity against the bean pathogen. It is suggested that S 97 might evolve substances already during seed germination that are translocated to the foliage; there they might accumulate around the site of bacterial multiplication and contribute to their restricted growth.
Eleven strains of Torulaspora and Zygosaccharomyces species were examined for the partial base sequences of 18S and 26S rRNAs. In the partial base sequences in positions 493-622 (130 bases) of 26S rRNA, there were 88-91% and 70-92% maximum homologies within the genera Torulaspora and Zygosaccharomyces, respectively. The maximum homologies were 70-90% between the two genera. The species of the two genera had 73-88% maximum homologies with Saccharomyces cerevisiae. In the partial base sequences in positions 1611-1835 (225 bases) of 26S rRNA, there were 3-0 and 16-1 base differences within the two genera, respectively. The base differences were 15-0 between the two genera. The two genera had 17-8 base differences with S. cerevisiae. In the partial base sequences in positions 1451-1618 (168 bases) of 18S rRNA, there were 0 and 3-0 base differences within the two genera, respectively. The base differences were 2-0 between the two genera. The two genera had 3-1 base differences with S. cerevisiae. Zygosaccharomyces cidri and Z. fermentati occupied a unique situation (base differences, 3-2). The data obtained were discussed with regard to the phylogenetic relationships and the taxonomic positions of Torulaspora, Zygosaccharomyces, and Saccharomyces.