We compared phenotypic characteristics of Lactococcus lactis subsp. lactis derived from different sources including the intestinal tract of marine fish and freshwater fish, and cheese starter culture.In the phylogenetic analysis based on partial 16S rRNA gene nucleotide sequences (1371 bp), freshwater fish-, marine fish- and cheese starter culture-derived strains were identical to that of L. lactis subsp. lactis previously reported. Fermentation profiles determined using the API 50 CH system were similar except for fermentation of several sugars including l-arabinose, mannitol, amygdalin, saccharose, trehalose, inulin and gluconate. The strains did have distinct levels of halotolerance: marine fish-derived strains > cheese starter-derived strain > freshwater fish-derived isolate.Lactococcus lactis subsp. lactis showed extensive diversity in phenotypic adaptation to various environments. The phenotypic properties of these strains suggested that L. lactis subsp. lactis strains from fish intestine have additional functions compared with the cheese starter-derived strain that has previously described.The unique phenotypic traits of the fish intestinal tract-derived L. lactis subsp. lactis might make them useful as a probiotics in aquaculture, and contribute to the development of functional foods and novel food additives, since the strains derived from fish intestines might have additional functions such as antibacterial activity.
Sequencing analysis of the partial control region ( c. 450 bp) detected 88 haplotypes from 249 individuals of Girella punctata collected from coastal waters of nine locations in the Japanese Islands. A single haplotype was the most numerous at all sampling locations, and no significant genetic difference was found among G. punctata samples collected from various locations ( F ST =−0·0274 to 0·0247) with high haplotype diversity and low nucleotide diversity, suggesting that G. punctata population had experienced a bottleneck followed by rapid population growth around the Japanese Islands and might be affected by larval dispersal in association with warm currents.
Abstract Itoi, S., Saito, T., Shimojo, M., Washio, S., and Sugita, H. 2007. Identification of Girella punctata and G. leonina by PCR-RFLP analysis. – ICES Journal of Marine Science, 64: 328–331. Two Girella species, Girella punctata and G. leonina, are sympatric sister species with an extensive overlap in their respective distributions on shallow rocky reefs from Hong Kong to the south of the Japanese Islands. Juveniles of the two species cannot be discriminated easily on the basis of external characters. In this study, after morphological identification of the species, sequencing analysis was carried out for the partial 16S ribosomal RNA gene and for the D-loop region in mitochondrial DNA. A total of 109 specimens was examined. Restriction site mapping of the sequences suggested that the electrophoretic patterns of polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) analysis of the gene products would produce a species-specific banding pattern. Subsequently, the PCR-RFLP analysis showed that the method was as effective for separating the two morphologically similar species of the genus Girella as the sequencing analysis.
