Recent advances in enzyme immobilization / 生物工程学报

Enzyme is an efficient and green biocatalyst, and widely used in many areas. Immobilized enzyme is superior to its free form in a variety of properties. Enzyme immobilization studies started in the 1970s in China. Till now, immobilized enzymes are widely applied in the fields of food, medical, energy, environmental management, among others. However, there are still some defects such as no universal method and the high cost. Therefore, based on the relatively mature traditional immobilization technologies, efforts have been made to innovate immobilization technologies. As a result, many new immobilization technologies focusing on new carriers and methods are continuously generated. Coupling with more than ten years' study on enzyme immobilization, we present here recent development and application of new immobilization technologies, as well as suggestions to future development of immobilization technology.

Role of visfatin in the pathogenesis of gestational diabetes mellitus and its relationship with insulin resistance / 中华妇产科杂志

Objective To investigate the role of visfatin in the pathogenesis of gestational diabetes mellitus (GDM)and its correlation with insulin resistance.Methods The study recruited 58 pregnant women of 24 to 28 gestational weeks in People' s Hospital of Hebei Province from January to June 2013.Among them,30 were patients with GDM (GDM group),28 had normal oral glucose tolerance test and was referred as healthy pregnancy group (NGT group).Fourteen age-matched female who were first-degree relatives (FDR1)of type 2 diabetes mellitus patients,and 27 healthy nonpregnant women with normal oral glucose tolerance test were referred as high-risk group and normal controls (NC),respectively.The fasting plasma glucose (FPG),1 hour and 2 hours postprandial glucose levels were measured by glucose oxidase method.The fasting insulin (FIN)levels were measured by radioimmunoassay and the homeostatic model assessment-insulin resistance index (HOMA-IR)was calculated.The levels of total cholesterol (TC),triglycerdes (TG),high density lipoprotein cholesterol (HDL)and low density lipoprotein cholesterol (LDL)were determined.The visfatin levels were measured by ELISA.Results (1)The levels of FPG were significantly higher in GDM,FDRI and NC group [(5.5±0.7),(5.1±0.6),(5.2±0.4) mmol/L] than that in NGT group [(4.5 ± 0.3) mmol/L],respectively (P＜0.05).(2) The levels of INS [(14 ± 6) mU/L],HO MA-I R (4.0±2.0),1 hour [(10.9± 1.8) mmol/L] and 2 hours [(8.6± 1.8) mmol/L] postprandial glucose levels of GDM group were significantly higher than those in NGT group [(12±4) mU/L,2.0± 1.0,(7.4± 1.3) and (6.2 ±0.9) mmol/L],respectively (P＜0.05).(3)The levels of TC,TG,HDL and LDL levels in GDM group were (5.5±0.9),(2.8±0.8),(1.8±0.4)and(3.3±0.8) mmol/L,and were(5.9 ± 0.8),(2.5 ± 0.7),(1.9 ± 0.4) and (3.4 ± 0.6) mmol/L in NGT group.The levels of lipid in the two groups were significantly higher than those in FDR 1 or NC group,respectively (P＜0.05).(4) The levels of visfatin in GDM group and NGT group [(43 ± 10),(45 ± 12) μg/L] were significantly higher than that in FDR1 or NC group [(29±9),(36±7) μg/L],respectively (P＜0.05),but the visfatin levels in FDR 1 group were significantly lower than that in NC group (P＜0.05).The visfatin levels in GDM group were slightly lower than that in NGT group,but the difference was not statistically significant (P＞0.05).(5)The visfatin levels in NGT group were negatively correlated to the levels of FPG,HOMA-IR and TC(r=-0.38,-0.44,-0.47,respectively,P＜0.05).But the visfatin levels in GDM group were not correlated with the levels of FPG,HOMA-IR,TC (r=-0.16,-0.01,0.33,respectively,P＞ 0.05).While in NC group,the levels of visfatin were negatively correlated with FPG and 2 hours postprandial glucose (r=-0.48,-0.42,respectively,P＜0.05).Conclusion Visfatin may be an important adipokine that involved in the carbohydrate and lipid metabolism in GDM,and is related to the pathogensis of GDM and insulin resistance.

Polysaccharides from Scurrula parasitica L. inhibit sarcoma S180 growth in mice / 中国中药杂志

To study the anti-tumor activity of Scurrula parasitica polysaccharides (SP). Water extraction and ethanol precipitation were used to isolate SP from S. parasitica leaf. S180, K562 and HL-60 cell lines proliferation inhibition by SP were detected by MTT assay. The expressions of Ki-67, Cyclin D1, Bax and Bcl-2 protein in the sarcoma S180 tissues were detected by immunohistochemistry technique to approach the anti-tumor mechanism of SP+ SP could not inhibit cancer cell proliferation. SP ip could inhibit the growth of sarcoma S180 in mice, 100 mg x kg(-1) x d(-1). SP ip was the optimal dose on inhibiting S180 growth, with the tumor inhibition rate of 54%. The expression of Ki-67, Cyclin D1, Bax and Bcl-2 protein in the sarcoma S180 tissues were detected by immunohistochemistry technique to approach the anti-tumor mechanism of SP. The result showed that SP could down-regulate the expression of Ki-67, CyclinD1 and Bcl-2 protein, and up-regulate the expression of Bax protein. It indicted that inhibiting cancer cell proliferation and promoting cancer cell apoptosis in vivo maybe one of the anti-cancer mechanisms of SP.

Optimization of bacterial cellulose fermentation medium and observation of bacterial cellulose ultra-micro-structure / 生物工程学报

In order to improve the yield of bacterial cellulose (BC), the fermentation medium of BC-producing strain J2 (Gluconobacter) was optimized, and BC ultra-micro-structure was observed. Initially, Plackett-Burman design was employed to evaluate eight variables which were relevant to BC production. Three statistically significant parameters including yeast extract, ZnSO4, ethanol were selected and other 5 variables were not significant (P > 0.05). The optimized levels of three variables were defined by Box-Behnken design and response surface methodology (RSM). BC ultra-micro-structure was observed by scanning electron microscope (SEM) with cotton cellulose as comparison. The results indicated that the BC yield under the optimum fermentation medium was 11.52 g/100 mL, which was as 1.35 times as that under the original fermentation medium. The SEM photos manifested that bacterial cellulose ribbon, with a diameter less than 0.1 microm, was less than cotton cellulose ribbon. The bacteria inside the cellulose net were eliminated after the NaOH treatment.