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Muscle fiber is the basic unit of skeletal muscle. Muscle fiber types play a crucial role in improving meat quality. In the current study, Wistar rats were chronic injected with 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) for four weeks in order to define the 5′-AMP-activated protein kinase (AMPK) protein activity on muscle fiber composition, enzyme activity and the mRNA expression of muscle fiber type-related genes in gastrocnemius (GS) muscle. Food intake and body weight did not show a significant difference after AICAR treatment (P >.05). The AICAR treatment caused a significantly increased number and area proportion of type I muscle fiber and expression level MyHC I mRNA (P <.05), succinic dehydrogenase (SDH) and malate dehydrogenase (MDH) activities (P <.05), but decrease in the number proportion of type IIB muscle fiber and MyHC IIb and MyHC IIx mRNA level (P <.05). The Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) mRNA level (P <.05) was increased and glucose transporter 4 (GLUT-4) mRNA level tended to be higher (P =.052) in the AICAR group. These results demonstrated that chronic AICRA treatment induces oxidative muscle fiber switching, enhances oxidative enzyme activity and GLUT4 mRNA level, mediated by PGC-1α. [ABSTRACT FROM AUTHOR]

With the tremendous success of the artificial breeding of Hexagrammos otakii , the yield has been substantially improved. However, intensive farming often results in bacterial diseases; hence it is imperative to find new antimicrobial molecules. In the present study, we identified a homologous cDNA fragment of collectin-10 from H. otakii , designated as HoCL-10. The cDNA length is 899 bp, which contains an open reading frame (ORF) of 816 bp encoding a secreted protein with 272 amino acid residues. The peptide of HoCL-10 contains an N-terminal collagen domain, a neck region, and a C-terminal carbohydrate recognition domain. The qRT-PCR results revealed that HoCL-10 mRNA was highest expressed in the liver and skin and was significantly induced post-LPS stimulation. The sugar and bacteria binding assay suggested that the recombinant HoCL-10 (rHoCL-10) could recognize various pathogen-associated molecular patterns (PAMPs) and bacteria. For effect on cells, rHoCL-10 enhanced the phagocytosis and migration ability of the macrophage indicated using pro-phagocytosis assay and trans -well assay. To determine the role of HoCL-10 in the complement system, the interaction between HoCL-10 and mannose-binding lectin associated serine protease 1, 2 (MASP-1, 2) were analyzed and demonstrated using ELISA and Far-western. And in vivo , the concentration of membrane-attack complex (MAC) in fish plasma was significantly down-regulated post-injection with HoCL-10 antibody. Finally, the bacteria challenge experiment was performed, implying that HoCL-10 may assist the host in defending against microbial invasion. The findings suggest that HoCL-10 may play crucial roles in host defense against microorganisms, possibly through opsonizing pathogens and activating the complement system. • A collectin-10 gene from Hexagrammos otakii (HoCL-10) was identified. • HoCL-10 mRNAs were up-regulated in the liver and skin post LPS stimulation. • The recombination protein of HoCL-10 (rHoCL-10) recognized PAMPs and microbials. • rHoCL-10 may function in the complement activation process and anti-infections. [ABSTRACT FROM AUTHOR]