Isolation, identification and prokaryotic expression of a bacteriocin-like substance from Bacillus licheniformis / 生物工程学报

The ban on addition of antibiotics in animal feed in China has made the search for new antibiotics substitutes, e.g. bacteriocin, a hot topic in research. The present study successfully isolated an antibacterial substance producing strain of Bacillus sp. from alpaca feces by agar diffusion method, using Escherichia coli, Salmonella enterica, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus and Listeria monocytogenes as indicator bacteria. The isolated strain was named as B. licheniformis SXAU06 based on colony morphology, Gram staining and 16S rRNA gene sequence. The antibacterial substance was isolated and purified through a series of procedures including (NH4)2SO4 precipitation, chloroform extraction, molecular interception and SDS-PAGE analysis. Bioinformatics analysis of the LC-MS/MS data indicated that the antibacterial substance was a bacteriocin-like substance (BLIS) with an approximate molecular weight of 14 kDa, and it was designated as BLIS_SXAU06. BLIS_SXAU06 exhibited high resistance to treatment of proteinase K, high temperature, high acidity and alkalinity. BLIS_SXAU06 was heterologously expressed in E. coli and the recombinant BLIS_SXAU06 exhibited effective antibacterial activity against S. aureus, S. epidermidis, M. luteus, and L. monocytogenes, showing potential to be investigated further.

Effect of Hypoxia on the Muscle Fiber Switching Signal Pathways CnA/NFATc1 and Myostatin in Mouse Myocytes.

This study investigated the effects of a CoCl2-simulated hypoxic environment on the muscle fiber switching signaling pathways calcineurin A/nuclear factor of activated T cells cytoplasmic 1 (CnA/NFATc1) and myostatin. In this study, C2C12 muscle cells were cultured in vitro under CoCl2-simulated chemical hypoxic conditions, the expression levels of CnA and myostatin were detected through qRT-PCR and Western blot analyses, and a positioning study of NFATc1 was carried out by immunofluorescence labeling. Results showed that CoCl2 treatment significantly increased the expression levels of CnA and myostatin. Moreover, the position of NFATc1 expression changed; actually, its expression in the nucleus considerably increased. Furthermore, CoCl2-induced hypoxia inhibited the differentiation of C2C12 cells and reduced the expression levels of many slow- and fast-twitch muscles marker genes, but immunofluorescence staining results showed that the proportion of MyHC I type muscle fiber increased after CoCl2 treatment. The hypoxic environment simulated by CoCl2 can activate the signaling pathways CnA/NFATc1 and myostatin and increases the proportion of MyHC I type muscle fibers.

Expression of HGF/c-met in the hair follicle growth cycle in mice / 中国实验动物学报

Objective HGF and its receptor ( c-met) are principal mediators of mesenchymal-epithelial interac-tion in several different systems.Moreover, hair follicle is a model of mesenchymal-epithelial interaction.The aim of this study was to explore whether HGF/c-met signal plays a role in the control of hair follicle growth cycle.Methods To ex-amine the localization of HGF/c-met in anagen, catagen and telogen in the hair follicle of ICR mice.Results HGF was mainly located in the dermal papilla and sebaceous gland, and c-Met in the hair matrix, root sheath and epidermis.Both HGF and c-met expressions peaked during anagen, not found in catagen, and increased during telogen-anagen phase.Con-clusions Our results demonstrate a regulatory role of HGF and c-met in the control of hair follicle growth in ICR mice.