The taxonomy is important not only for the scientific interest but also for the evaluation of biological research and intellectual property rights. It may be convenient for microbiologists, but not for taxonomists, to use scientific names with fixed concept without change. However, taxonomy is a dynamic science allowing the study of relationships between organisms and considering their function and evolution. Scientific names should be given to bacteria under a common regulation within the scientific community. “The International Code of Nomenclature of Bacteria” has this function under International Union of Microbiological Societies. This paper briefly reviews the Bacteriological Code and its implications using some examples in the taxonomy of lactic acid bacteria.

View full abstract

Soy Sauce (Shoyu) is one of the most representative Japanese traditional fermented foods and has recently become increasingly popular throughout the world.
During the moromi-fermentation of soy sauce making processes, a group of lactic acid cocci known as Tetragenococcus halophilus proliferate in moromi-mash which contains a high concentration of sodium chloride, around 18% (w/v), and produce nearly 1% (w/v) of L-lactic acid. In the early 1980's, a technique for discriminating individual strains was developed, and as a result the diversity in physiological properties among the natural flora of soy lactic acid bacteria has become well known. A wide variety of strains have been found based on physiological properties such as arginine degradation, aspartate decarboxylation, amine-formation from histidine, phenylalanine or tyrosine, consumption of citric or malic acids, and reduction of environmental red-ox potentials, besides in utilization of carbohydrates. Diversity among strains was also observed in their phage-susceptibility and plasmid-profiles. Many of these activities substantially affect the quality of the end products. Accordingly, strain-level control of the fermenting microbes is needed for preparation of high quality soy sauce.
Significance of this diversity and possible mechanisms which might have produced it were also discussed from a microbial ecology perspective.

View full abstract

The results in this paper were presented in the symposium on “Traditional Fermented Foods: Microbial Ecology and Technology” held on August 1,1998, at Hokkaido University, Sapporo, Japan.

View full abstract

The binding mechanism of Trp-P-1 to Lactococcus lactis subsp. lactis strain H1 and Lactococcus lactis subsp. cremorisstrain H12 isolated from starter culture of Scandinavian traditional ropy sour milk “Langfil” was investigated. Binding of cells with Trp-P-1 was affected by altering pH in both strains. The strongest binding was observed at pH5-6, and the binding ability decreased below pH5 and above pH 6. The surface charges of strain H1 and H12 cells were determined by colloid titration. The isoelectric point was pH1.7 in both strains, and the negative charge of cells increased above the pH. The pKa of Trp-P-1 was 7.7. These results suggest that the binding mechanism of Trp-P-1 to both strains H 1 and H12 results from a cation-exchange effect.

View full abstract

Some of the properties of a PL-1 phage resistant-mutant (strain YIT 9021) of Lactobacillus asei ATCC 27092, which adsorbs the phage particles normally, but is not infected by the phages, were studied. The formation of the phage-infective centers (PFU remaining after neutralization with anti-PL-1 rabbit serum) was suppressed as compared with that of the wild strain. Cell-lysis of the mutant strain did not occur at a high multiplicity of infection, where that of the wild strain occurred efficiently. The formation of irreversible phage-cell complexes determined by our L-rhamnose method occurred on a much lower level than that of the wild strain. The transfection efficiency of the protoplasts by the naked phage DNA was less than one-hundredth that with the wild strain. These results supported the view that the injection of the phage genome into the cell would be blocked in the YIT 9021 strain.

View full abstract