Yan S.,Dalian Jiaotong University |
Lin X.,Capitial Medical University |
Chen X.,National Marine Environmental Monitoring Center |
Zhang S.,Dalian Jiaotong University
Journal of Pure and Applied Microbiology | Year: 2014
A Gram-positive bacillus designated as strain whb27 with high esterase hydrolysis activity was screening from 35 strains of moderately halophilic bacteria isolated from brine and sediment of saltern in Weihai, China. Phenotypic characterization and phylogenetic analysis based on 16S rDNA sequence comparison indicated that the strain was Halobacillus trueperi. Whb27 grew optimally at 7% NaCl, pH 7.5 and 28°C. A halophilic esterase was purified to homogeneity from the crude extract of whb27 by ammonium sulphate fractionation followed by ion exchange and gel permeation chromatography, with a 42-fold purification. The molecular mass of the enzyme was about 35 kDa as assessed by polyacrylamide gel electrophoresis. The enzyme showed maximum activity in the presence of 2.5M NaCl. The optimum temperature and pH were 42°C and 8.0, respectively. The Ba2+ and Fe2+ ions inhibited the activity of the esterase while Ca2+, Mn2+ and Zn 2+ ions stimulated its activity. In the presence of EDTA, SDS, DMSO, glycol and acetone, the esterase still displayed some activity, but the activity could be inhibited significantly by phenyl methyl sulphonyl fluoride (PMSF). One interesting point is that organic solvents like ethanol, glycerol, propylene glycol, PEG4000 stabilized or enhanced enzymatic activity, making the enzyme very useful in some industrial process.
Xishan Z.,Capitial Medical University |
Baoxin H.,Capitial Medical University |
Xinna Z.,Capitial Medical University |
Jun R.,Capitial Medical University
Cell Biology International | Year: 2013
Mesenchymal stem cells (MSCs) are multipotent cells that can be derived either from the bone marrow (bMSCs) or adipose tissue (aMSCs).We have compared the immune regulatory properties of cells derived from bone marrow and adipose tissue to provide a theoretical basis for the choice of stem cell source for transplantation. The phenotypes of bMSCs and aMSCs are similar, differing only in the expression of CD106. aMSCs proliferate faster than bMSCs, but aMSCs suppressed T-lymphocyte proliferation and activation more poorly than bMSCs. Thus cell origin and abundance are important factors in determining the suitability of MSCs for transplantation. Adipose tissue offers a more promising source of cells for such an application. © 2012 International Federation for Cell Biology.