Abstract In the current research, edible meat of freshwater clam Corbicula fluminea was subjected to enzymatic peptide extraction using animal protease. The clam protein hydrolysate (CPH) contained 45.78% essential amino acids and 44.97% hydrophobic amino acids and showed high alcohol dehydrogenase (ADH) activation in vitro. Four fractions were divided from CPH by ultrafiltration and further investigated for their hepatoprotective effects on alcohol-induced injury in mice. The 2.5-5 kDa fraction (CPH-3) showed the best effect for preventing hepatic damage caused by alcohol, as revealed by reduced serum aspartate transaminase (AST) and alanine transaminase (ALT) activities and hepatic malondialdehyde (MDA) level, the marked decrease in the hepatic triglyceride (TG) contents, and the enhanced hepatic ADH, aldehyde dehydrogenase (ALDH), and glutathione (GSH) activities. Furthermore, histopathology of CPH-3-treated mice showed less hepatic tissue damage compared to alcohol- or other CPHs-treated mice. Hence, CPH-3 was further purified by consecutive chromatographic techniques with gel filtration and reverse-phase high-performance liquid chromatography. One hepatoprotective peptide, KKLAGFLRYYS (1330.68 Da), was identified by LC-MS/MS, which exhibited strong ADH activation activity. Results suggested that CPH could be a potential nutraceutical for facilitating alcohol metabolism and preventing or ameliorating early liver injury induced by acute alcohol exposure and that the peptide KKLAGFLRYYS is one of the main bioactive components in CPH.

Abstract As a glacier retreats, barren areas are exposed, and these barren areas are ideal sites to study microbial succession. In this study, we characterized the soil culturable bacterial communities and biochemical parameters of early successional soils from a receding glacier in the Tianshan Mountains. The total number of culturable bacteria ranged from 2.19 × 105 to 1.30 × 106 CFU g-1 dw and from 9.33 × 105 to 2.53 × 106 CFU g-1 dw at 4 °C and 25 °C, respectively. The number of culturable bacteria in the soil increased at 25 °C but decreased at 4 °C along the chronosequence. The total organic carbon, total nitrogen content, and enzymatic activity were relatively low in the glacier foreland. The number of culturable bacteria isolated at 25 °C was significantly positively correlated with the TOC and TN as well as the soil urease, protease, polyphenoloxidase, sucrase, catalase, and dehydrogenase activities. We obtained 358 isolates from the glacier foreland soils that clustered into 35 groups using amplified ribosomal DNA restriction analysis. These groups are affiliated with 20 genera that belong to six taxa, namely, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Actinobacteria, Bacteroides, and Deinococcus-Thermus, with a predominance of members of Actinobacteria and Proteobacteria in all of the samples. A redundancy analysis showed that the bacterial succession was divided into three periods, an early stage (10a), a middle stage (25-74a), and a late stage (100-130a), with the total number of culturable bacteria mainly being affected by the soil enzymatic activity, suggesting that the microbial succession correlated with the soil age along the foreland.