No abstract

No abstract

Telomerase is a unique reverse transcriptase involved in the maintenance of telomeric DNA, which is generally undetectable in normal human somatic cells. However, it has been found in organs of normal adult rodents including the liver. In order to elucidate relevant control mechanisms operating in normal somatic cells, we examined telomerase activity in primary cultured rat hepatocytes. During culture under serum-free conditions, rat hepatocytes rapidly lose the ability of organ-specific expression of serum albumin, apolipoprotein A-I, and hepatocyte nuclear factor 4, and the capacity for cytochrome P-450 induction by xenobiotics. The telomerase activity was found to be concomitantly increased about 2. 5-fold at 48 h and 3-fold at 72 h. Northern blot and RT-PCR analyses with primary cultured hepatocytes revealed the associated accumulation of rat telomerase RNA subunits (TR), and the mRNAs for a telomerase reverse transcriptase (TERT) and a telomerase-associated protein (TEP1). The activity of hepatocyte telomerase, which was elevated during the primary culture, increased further when the cells were stimulated with hepatocyte growth factor. In this case, however, the levels of TR, TERT, and TEP1 mRNA did not show any detectable changes.

Narezushi is one of Japanese traditional foods and is made by fermenting salted fish meat and cooked rice together. In this study, the microbial diversity of samma-narezushi (narezushi using saury, Cobolabis saira) was analyzed by the 16S ribosomal RNA gene (rDNA) clone library. Randomly selected 89 clones were sequenced and phylogenetically analyzed. The sequences were classified into 12 operational taxonomy units (OTUs) at the 97% identity threshold.Most of the clones (89%) were lactic acid bacteria (LAB) and included Lactobacillus sakei, Leuconostoc gelidum, Lactococcus subsp. lads and L. pisium. The most predominant clone was L. sakei at 72% of the clones. The second most abundant clone was L. gelidum. These results suggest that L. sakei mainly contributes to the lactic acid fermentation process, taste and flavor of samma-narezushi.The present study showed that the culture independent method is useful for the microbial diversity analysis of narezushi.Key words: Narezushi/Fermented food/Lactic acid bacteria/Lactobacillus sakei/16S rDNA clone library.

A bacterium that was isolated from soil and identified as Bacillus circulans was found to produce a highly viscous extracellular polysaccharide when it was grown aerobically in a medium containing glucose as a sole source of carbon. The product was characterized by TLC and GC analyses as a novel heteropolysaccharide consisted of rhamnose, mannose, galactose, and mannuronic acid as sugar components. A maximal yield of polysaccharide reached about 2 g/liter by jar-fermentor culture at 30°C for 48 hr with a medium containing 1% glucose, 0.05% asparagine, 0.005% yeast extract, and small amounts of inorganic salts. Some culture conditions for the production of polysaccharide were investigated with flask culture; an optimal production was attained with a medium containing 0.1-1 % glucose and 0.01-0.05% asparagine, pH 7-8, at 30°C under aerobic conditions.