Protective effects of polysaccharides from Dendrobium huoshanense on CCl4-induced acute liver injury in mice / 中国中药杂志

<p><b>OBJECTIVE</b>To study the protective effects of polysaccharides from Dendrobium huoshanense (DHP) against CCl4-induced liver injury in mice.</p><p><b>METHOD</b>Eighty male Kunming mice were randomly divided into normal control group, model control group, dextran control group, starch control group, hydrolyzate control group, three different dose of DPH groups consisting of high-dosage group, middle-dosage group and low-dosage group (200, 100, 50 mg x kg(-1)). Each group contained ten mice. The mice were treated with DHP via intragastric administration for 15 days before treatment of 50% CCl4 in olive oil for consecutive two days. Both alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum and superoxide dismutase (SOD) activities and malondialdehyde (MDA) contents in liver tissues were determined in all groups. Immunohistochemistry was used to detect the expression of TNF-alpha in hepatic tissue. Hepatic histopathological examination was observed.</p><p><b>RESULT</b>DHP effectively decreased the activities of ALT and AST in serum and the contents of hepatic MDA, and restored hepatic SOD activities in acute liver injury mice. Liver tissue damage induced by CCl4 was ameliorated in mice with DHP administration through histopathology examination. Furthermore, the expression of TNF-alpha was greatly decreased in groups treated with polysaccharides.</p><p><b>CONCLUSION</b>DHP has a significantly hepatoprotective effect on CCl4-induced acute liver injury in mice. Protective effect of DHP on the liver may be related to its function of scavenging free radicals and inhibiting lipid peroxidation and TNF-alpha expression.</p>

Study on isoflavone active aglycone preparation by immobilized beta-glucosidase from Aspergillus niger / 生物工程学报

With sodium alginate as a carrier and glutaraldehyde as the crosslinking agent, an improved immobilization method of beta-glucosidase for production of soybean genistein was developed. As compared with entrapment or entrapment-crosslinkage, crosslinkage-entrapment that beta-glucosidase was treated with glutaraldehyde and then entrapped in sodium alginate remained high loading efficiency and activity recovery, Effects of bead sizes, concentrations of alginate and glutaraldehyde as well, on the loading efficiency and activity recovery were assessed. When compared with the free enzyme, the optimum temperature, pH value and Km of the immobilized beta-glucosidase were respectively shifted from 50 degrees C to 40 degrees C, 4.5 to 4.0 and 2.57 microg/mL to 2.02 miocrog/mL. The stabilities of the immobilized beta-glucosidase were considerably better than that of the native enzyme. The immobilized beta-glucosidase was employed to genistein production, 84.94% of the activity and 56.04% of conversion were kept after consecutive use of 6 times.

Inhibitory effects of mifepristone on the growth of human gastric cancer cell line MKN-45 in vitro and in vivo / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To explore the effects of mifepristone on the growth of human gastric cancer cell line MKN-45 and its possible mechanisms.</p><p><b>METHODS</b>In situ hybridization was used to detect the expression of progesterone receptor (PR) mRNA in MKN-45 cells. Proliferation, cell cycle distribution, and the expression of Bcl-xL and vascular endothelial growth factor (VEGF) of MKN-45 cells incubated with various concentrations of mifepristone (1, 5, 10, and 20 micromol/L) were analyzed using MTT reduction assay, flow cytometry, reverse transcription-polymerase chain reaction (RT-PCR), and enzyme-linked immunoabsorbent assay (ELISA), respectively. After transplantation of MKN-45 cells underneath the skin of athymic mice, mifepristone was administrated with the dose of 50 mg/(kg x d) for 6 weeks to evaluate the tumor growth. Apoptosis and the expression of proliferating cell nuclear antigen (PCNA) in xenografted tumors were detected using transmission electron microscopy and immunohistochemical staining, respectively.</p><p><b>RESULTS</b>PR mRNA was highly expressed in cultured MKN-45 cell. Mifepristone dose-dependently inhibited the proliferation of MKN-45 cells, and the inhibitory rate was dramatically increased from 7.21% to 47.23%. The inhibitory effect was accompanied by a dose-dependent increase in the percentage of cells in G0/G1 phase, and with a concurrent decrease in the proportion of S- and G2M-phase cells and the proliferative index from 57.65% to 24.54%. Meanwhile, mifepristone down-regulated the expression of Bcl-xL and VEGF in a dose-dependent manner. In vivo, mifepristone effectively inhibited the growth of xenografted tumors in nude mice (55.14% for inhibitory rate), induced apoptosis, and down-regulated PCNA expression in gastric cancer.</p><p><b>CONCLUSION</b>Mifepristone exerts significant growth inhibitory effects on PR-positive human MKN-45 gastric cancer cells via multiple mechanisms, and may be a beneficial agent against the tumor.</p>

SCREENING AND CHARACTERIZATION OF A PHENOL-DEGRADING BACTERIUM / 微生物学通报

A strain ph 16 , that could effectively degrade phenol,was isolated from sewer sludge of printing and dyeing plant. The preliminary identification sugg ested that the strain belongs to Micrococcus sp. The strain could resist to phenol up to 1.5 g/L. The efficient biodegradation of phenol occurred when th e strain was cultured in the medium (pH 7.0) containing 1.0 g/L phenol under 35℃, wh er e the highest degradation rate reach 99.6% after 36 hours. This strain, when t re ated with some heavy metal ions such as Hg +、Co 2+ and Ag 2+ , showe d the significant inhibition of phenol degradation by 74.2%～100%. The kinetic s of phenol degradation during culture of the strain was also explored.