Modulation of K+ channels by Ca2+ and pH in regulatory volume decrease

It has been widely appreciated that animal cells rely on the mechanism of regulatory volume decrease(RVD) after swell in a hypotonic environment. Activation of K channels is crucial in the process of self-protection. There are a characterized increase in cytoplasmic Ca and a decrease in pH in the process of RVD in many cell types. Ca entry via transient receptor potential(TRP) channel is crucial for the cytoplasmic Ca increase, which in turn induces the decrease in pH.The increase in cytoplasmic Ca and decrease in pH activate or inhibit the activity of K channel, respectively. In this review, the regulatory network at cellular level between cytoplasmic Ca and pH, and the modulation of K channels by Ca and pH in the process of RVD are discussed.     

Isolation, purification and identification of polysaccharides from cultured Cordyceps militaris

Four polysaccharides from the water extract of cultured Cordyceps militaris were isolated through ethanol precipitation, deproteination and gel-filtration chromatography. Their molecular weights were determined using gel-filtration chromatography. Among the four isolated polysaccharides, the structures of two of them (CPS-2 and CPS-3) were elucidated by sugar analysis, Smith degradation, IR and (13)C-NMR spectroscopy.     

基于森林资源节约的出版规范改进研究

针对当前我国森林资源和文字规范工作的实际情况,在统计分析了森林资源流向、书刊发行现状的基础上,从节约资源的角度出发,应用工业工程的理论思想和方法对文字的规范标准及纸张节约等相关问题进行分析研究,提出了具有较强操作性和实际意义的改进方法。     

Association between methylation status of apoptosis-related genes and chemosensitivity of lung adenocarcinoma cell line P15

AIM: To investigate the association between methylation status of apoptosis-related genes and chemosensitivity in the lung adenocarcinoma cell line P15.METHODS: Methylation-specific PCR was applied to detect the methylation status of p73, p14^ARF, p16^INK4a and bax genes of P15 cells in untreated control group and decitabine (DAC) treatment group. RT-PCR was used to detect the expression of p73, bcl-xL, bad, bax, p14^ARF and p16^INK4a at mRNA level. Colony formation assay and cell growth inhibition assay were used to detect the sensitivity of P15 cells to cis-diaminedichloroplatinum (C-DDP) before and after DAC treatment. DAPI staining was used to determine the apoptosis of P15 cells exposed to C-DDP before and after DAC treatment. RESULTS: p73, p16^INK4a and bax were expressed in the methylation status. After DAC treatment, p16^INK4a expression was decreased, and the expression of p73 and bax disappeared. The expression of p73, p16^INK4a and bax in the unmethylated status was weak, but the enhanced expression was observed following DAC treatment. After P15 cells were treated with DAC and C-DDP, the colony formation rate of the P15 cells was significantly decreased as compared with untreated control group. The apoptotic P15 cells in DAC+C-DDP treatment group were significantly higher than those in untreated control group (P<0.05). CONCLUSION: After treated with DAC, the sensitivity of P15 cells to C-DDP is increased due to the activation of silenced pro-apoptotic genes. DAC and C-DDP synergistically promote tumor cell apoptosis. They have significant anti-tumor effect.     

Development of cell model of polymer/liquid crystal and effect of their elasticity on adhesion of rBM-MSCs

AIM: To develop the cell model of polymer/liquid crystal and to study the effect of their elasticity on the adhesion of rat bone marrow mesenchymal stem cells (rBM-MSCs). METHODS: Using the method of solvent evaporation induced phase separation, the cell model of polymer/liquid crystal was constructed. The surface morphology and phase separation structure were determined by polarized optical microscopy (POM), scanning electron microscopy (SEM) and small angle X-ray scattering (SAXS). rBM-MSCs were separated and expanded by adherent culture. The surface markers of rBM-MSCs were detected by flow cytometry. The cells were induced to osteogenic differentiation and adipogenic differentiation for 2 weeks. After 3 passages, the cells were divided into 4 groups, including total PU control group, 10% membrane group, 30% membrane group and 50% membrane group. The cells were then incubated with rhodamine phalloidin for cytoskeleton staining and were observed under the confocal laser scanning microscope after cultured for 24 h. RESULTS: The cell model of polymer/liquid crystal was constructed successfully using the method of solvent evaporation induced phase separation. Flow cytometry results showed that the rBM-MSCs positively expressed CD29, CD44 and CD90, and negatively expressed CD34 and CD45. After stained with alizarin red S and oil red O, the calcium nodule and lipid droplets in rBM-MSCs were observed obviously. The cytoskeleton staining result indicated that the area in total PU control group, 10% membrane group and 30% membrane group were greater, and the actin microfilaments were also clearer than that in 50% membrane group. CONCLUSION: The cell model with suitable content of liquid crystal made a contribution to the rBM-MSCs' adhesion, but too much liquid crystal inhibits cell adhesion.     

干旱处理对华北绣线菊和毛果绣线菊光合作用及相关蛋白表达的影响

以抗旱力弱的毛果绣线菊与抗旱力强的华北绣线菊为试验材料,采用不同程度干旱处理,在测定其光合作用变化的基础上,采用蛋白质组学技术研究两种绣线菊光合作用相关蛋白表达的变化。结果表明:干旱胁迫两种绣线菊光合能力降低,光补偿点和光饱和点降低,说明利用弱光能力提高,华北绣线菊适应弱光环境的能力强于毛果绣线菊。不同水平干旱处理分别鉴定出涉及能量代谢与运输的相关蛋白20种。干旱胁迫下毛果绣线菊中卡尔文循环途径相关酶、光系统Ⅱ中多数放氧复合蛋白和捕光色素复合蛋白、参与光合磷酸化的酶发生显著上调和下调表达;华北绣线菊中参与卡尔文循环代谢相关酶、PSⅠ中反应中心蛋白和参与光合电子传递的蛋白、PSⅡ中捕光色素复合蛋白、参与光合磷酸化与氧化磷酸化的蛋白发生明显的上调和下调表达。干旱胁迫使抗旱力不同的毛果绣线菊和华北绣线菊光合作用相关蛋白均受到影响,毛果绣线菊中多是能量代谢相关蛋白发生显著变化,华北绣线菊中多是能量运输相关蛋白发生显著变化。     

Preparation of recombinant PTD-HSP27 and verification of its ability to penetrate the cell membrane of human lens epithelial cells and rabbit cornea

AIM: To construct the prokaryotic expression system containing protein transduction domain (PTD) with heat shock protein 27 (HSP27) in order to prepare and purify the recombinant protein, and to verify whether the recombinant protein PTD-HSP27 has the ability to penetrate the human lens epithelial cell (HLEC) membrane and the rabbit cornea. METHODS: The plasmid pKYB-PTD-HSPB1-6His was constructed by the technique of overlap extension PCR. The plasmid was transformed and PTD-HSP27 was purified through nickel affinity chromatography column and identified by Western blotting. PTD-HSP27-6His was labeled with the fluorescein isothiocyanate (FITC). The penetrating ability of PTD-HSP27 into HLECs and rabbit cornea was tested. RESULTS: The recombinant PTD-HSP27 plasmid was successfully cloned and effectively expressed. The correctness of the recombinant protein PTD-HSP27 was demonstrated. Fluorescence microscopic examination showed that PTD-HSP27-FITC was internalized by HLECs. Fluorescent labeled PTD-HSP27 was then observed in the rabbit aqueous humor. CONCLUSION: The recombined gene PTD-HSPB1 was constructed by overlap extension PCR technique and the PTD-HSP27 fusion protein was prepared and purified by nickel affinity chromatography column. Using the technique of PTD-fusion protein, HSP27 was transduced into HLECs and passed through the cornea.     

Comparative development of mouse tooth germs transplanted in subrenal capsule and oral submucosa

AIM: To compare 2 environments, the subrenal capsule and oral submucosa, for producing well-formed teeth from mouse tooth germs and for exploring the ideal environment for tooth regeneration. METHODS: Two groups were set up. Group A was transplanted with the mouse embronic day (ED) 14.5 first mandibular molar tooth germs into the subrenal capsule, while group B was transplanted with the ED14.5 first mandibular molar tooth germs into the oral submucosa. After 3 weeks and 4 weeks, the host mice were sacrificed, and the transplanted explants were evaluated with morphologic observation, histological structures, hardness and elastictic modulus tests, and chemical compositions. RESULTS: (1) The explants isolated from both environments showed the tooth-like structures, but as to the group B, the crown was smaller, and the shape of the cusps was not significant. (2) HE staining showed that the dentin and enamel in group A were thicker than those in group B in which the ameloblasts and odontoblasts were differentiated not very well. (3) In the test of enamel hardness, only the hardness of 4 weeks in group B was lower than normal mouse tooth. In the test of enamel modulus, the elastic modulus of enamel in 3 weeks of group A was slightly lower than normal mouse tooth, but the difference was not significant.The elastic modulus of enamel in 4 weeks of group A and group B was significantly lower than normal mouse tooth and 3 weeks of group B. The hardness and elastic modulus of dentin in 3 groups was not significant. (4) Raman spectroscopy showed 2 groups grew in harmony in general, they all had the largest peak in the point of 961 cm^-1, but the 3 weeks of group B had an obvious peak in the point of 2 947 cm^-1. CONCLUSION: For the development of ED14.5 tooth germs, we obtain almost the whole tooth in subrenal capsule transplantation after 3 or 4 weeks. The buccal submucosa environment still has a certain influence on the tooth germ development, although there are some differences about the tooth development between this environment and subrenal capsule environment.     

Effect of gold nanoparticles on reversing adriamycin resistance of human hepatocellular carcinoma HepG2/ADM cells

AIM: To investigate whether gold nanoparticles (GNPs) reverses adriamycin (ADM), resistance of human hepatocellular carcinoma drug-resistant cell line HepG2/ADM and to explore the potential mechanism. METHODS: The sensitivities of HepG2 cells and HepG2/ADM cells to ADM were tested by MTT assay before and after GNPs pretreatment. The apoptotic rate was examined by flow cytometry. The concentration of ADM in HepG2/ADM or HepG2 cells was determined by ultraviolet-visible spectrophotometer. The content of glutathione (GSH) in HepG2/ADM or HepG2 cells by DTNB method. RESULTS: The half maximal inhibitory concentrations (IC₅₀) of ADM for HepG2/ADM cells were(29.46±1.73) mg/L and (15.18±0.85) mg/L before and after GNPs pretreatment,respectively. The IC₅₀ of ADM for HepG2 cells was (9.16±2.03) mg/L before pretreatment. The apoptotic rate in GNPs+ADM group was higher than that in ADM group (P<0.05). The concentration of ADM in HepG2/ADM group was lower than that in HepG2 group (P<0.01). After GNPs pretreatment, the concentration of ADM in HepG2/ADM cells was higher than that before pretreatment. The content of GSH in HepG2/ADM group was higher than that in HepG2 group (P<0.01). After GNPs pretreatment, the content of GSH in the HepG2/ADM cells was lower than that before pretreatment. CONCLUSION: Gold nanoparticles can reverse ADM resistance of human hepatocellular carcinoma drug-resistant cell line HepG2/ADM, reduce the content of GSH and increase the concentration of ADM in HepG2/ADM cells.