Many physiologically active hepatoprotective substances, such as those with antifibrotic activity, have been found in tea, fruits, and vegetables.1,2) The edible mushroom Lentinula edodes (shiitake) contains several bioactive compounds, including compounds with immunoprotective and antiatherogenic activities and one compound with an anti-human immunodeficiency virus (HIV) effect. [3][4][5] The mycelia of L. edodes can be cultured in solid medium, and the extract obtained by hot-water treatment (L.E.M.) is commercially available as a nutritional supplement. In our previous study, we found that L.E.M. exerts a hepatoprotective effect on dimethylnitrosamine (DMN)-induced liver fibrosis and Dgalactosamine-induced acute liver injury. 6,7) In the chronic liver injury model that uses DMN, the L.E.M. treatment suppressed the activation of hepatic stellate cells, which play a central role in liver fibrosis. The L.E.M. treatment also protected hepatocytes in the acute liver injury model that uses Dgalactosamine. We also found that the oral or intraperitoneal administration of L.E.M. suppressed immune-mediated liver injury. Therefore, L.E.M. is a promising plant extract for the prevention of liver failure. With the aim of developing effective drugs for liver diseases, we examined the protective effect of a single L.E.M. component against liver injury.The main components of L.E.M. are sugars, proteins, and polyphenolic compounds. The polyphenols act as antioxidants by scavenging reactive oxygen species (ROS), which produce oxidative stress and can adversely affect many cellular processes. Polyphenols have been proposed to protect against several diseases, including cancers, cardiovascular disease, and neurodegenerative disorders. [8][9][10] In our previous study, we found that the polyphenol-rich fraction of L.E.M. inhibits hepatic stellate cell activation, which is the

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Glucosyltransferases (GTF)-I and GTF-SI of Streptococcus mutans synthesize water-insoluble and both water-soluble and -insoluble glucans, respectively, and play essential roles in the sucrose-dependent adhesion of the organism to tooth surfaces. To examine the interactions of different GTFs on artificial biofilm formed by S. mutans and other oral streptococci, we generated GTF-I- and GTF-SI-hyperproducing isogenic mutant strains. Transformant B42-21, which hyperexpressed GTF-SI, exhibited firm adhesion in the presence of sucrose, whereas transformant B42-10, which hyperexpressed GTF-I, failed to exhibit firm adhesion. Furthermore, co-culture of transformant B42-21 with water-soluble glucan-synthesizing Streptococcus sanguinis yielded firm adhesion, while the addition of dextran T10 to B42-21 growing culture had no effect on adhesion. These findings suggest that GTF-SI has a strong effect on sucrose-dependent adhesion and is essential for biofilm formation on smooth surfaces, in cooperation with water-soluble glucans synthesized de novo by oral streptococci that inherently lack cell adhesion ability.

Quantitative microdilution plate hybridization was used to identify 22 Mycobacterium species. DNAs of clinical strains were rapidly extracted and labeled with photoreactive biotin. Labeled DNAs were distributed into wells of a microdilution plate in which reference DNAs had been immobilized. After 2 h of hybridization, hybridized DNAs were quantitatively detected with peroxidase-conjugated streptavidin and the substrate, tetramethylbenzidine. This method could differentiate among 20 of the 22 Mycobacterium species tested. The type strains of Mycobacterium tuberculosis and M. bovis were genetically highly related and could not be differentiated by this method. Of 194 biochemically identified human clinical strains, 178 (90%) were genetically identified within 3 h of the small-scale DNA extraction.