1-MCP对青脆李亚低温贮藏期间生理生化及品质的影响

以四川茂县青脆李为试材,研究1-甲基环丙烯(1-MCP)对亚低温(8±0.5℃)条件下青脆李的生理生化及其贮藏期间果实品质变化的影响。结果表明:1-MCP处理可显著抑制青脆李果实的呼吸作用和乙烯的释放速率,并降低两者的峰值;可保持果实细胞膜的完整性,降低PPO活性和酚类物质的消耗,减少褐变。其中以1.0μL.L-1浓度的1-MCP处理能够更有效地保持果实的质地与风味,亚低温条件下贮藏28 d,褐变指数为0,腐烂指数为5.3,显著好于对照和其他浓度的1-MCP处理,延长果实保鲜期达到20 d。     

rhEPO对缺糖缺氧大鼠星形胶质细胞GLT-1和GLAST表达的影响

为了研究重组人促红细胞生成素(rhEPO)对缺糖缺氧(OGD)培养大鼠星形胶质细胞GLT-1和GLAST表达的影响,将缺糖缺氧培养星形胶质细胞分成不同浓度rhEPO处理组:0、20、100U/mL,不同浓度rhEPO与星形胶质细胞在缺氧缺糖条件下培养6h,用RT-PCR测定GLT-1和GLAST的mRNA表达变化,免疫印迹技术测定GLT-1和GLAST蛋白的表达变化。20、100U/mL rhEPO星形胶质细胞GLT-1的mRNA和蛋白质水平较OGD对照组明显升高(P0.05),GLAST的mRNA和蛋白质水平变化不明显(P0.05)。GLT-1水平可能与rhEPO对缺糖缺氧培养大鼠星形胶质细胞的保护作用有关。     

Oxidized α1-antitrypsin induces IL-8 and MCP-1 production in HBE cells

AIM:To investigate the effect of oxidized α1-antitrypsin (Ox-AT) on interleukin 8 (IL-8) and monocyte chemotactic protein 1(MCP-1) production in cultured human bronchial epithelial (HBE) cells. METHODS:Plasma native α1-antitrypsin (N-AT) was purified from human plasma by 50% and 75% ammonium sulfate fractionation followed by glutathione and anion exchange chromatography. Ox-AT was prepared by incubating N-AT (0.5 g/L) with N-chlorosuccinimide in a 25-fold molar excess to N-AT in PBS at room temperature for 30 min. HBE cells were cultured in the presence of Ox-AT (0.5 g/L) for 4 h, 10 h and 24 h, and the levels of IL-8 and MCP-1 in the supernatant were assayed using respective DuoSet kits. The effect of NF-κB inhibitor Bay11-7082 on the inflammatory cytokine release induced by Ox-AT was also evaluated. RESULTS:Ox-AT concentration-dependently and time-dependently increased the production of IL-8 and MCP-1 in HBE cells. The concentrations of IL-8 and MCP-1 in HBE cells induced by 0.5 g/L Ox-AT at 4 h, 10 h and 24 h were significantly higher than those in blank control and N-AT groups. Ox-AT increased the activity of NF-κB in a dose-dependent manner. The proinflammatory effect of by Ox-AT was inhibited by NF-κB inhibitor Bay11-7082. CONCLUSION: Ox-AT is a strong proinflammatory factor for HBE cells. The mechanism is related to NF-κB signaling pathway activation.     

小鼠出生后背部毛囊发育与Lef-1表达的研究

旨在研究Lef-1在小鼠背部毛囊生长周期中的表达规律及其与毛囊生长更替的关系。本试验采用石蜡切片HE染色、Western blotting以及免疫组织化学方法,研究小鼠毛囊的周期性变化,检测Lef-1在小鼠毛囊生长的不同时期皮肤组织中的蛋白表达水平,并对其进行组织定位。结果,昆明系小鼠毛囊生长呈周期性变化,处于不同生长时期的毛囊具有各期的特殊结构;Western blotting结果显示,在各阶段皮肤组织中存在Lef-1蛋白的表达,其在毛囊生长初期的表达量显著高于中期和末期;免疫组织化学结果显示,Lef-1在不同毛囊生长时期的皮脂腺、根鞘和真皮乳头均有不同程度的表达。Lef-1的表达与毛囊的周期性变化存在相关性。     

Effects of tetrandrine and fructose-1, 6-diphosphate on the elevated intrasynaptosomal [Ca2+]i induced by excitatory amino acids

AIM: To study the effects of tetrandrine(Tet) and fructose-1, 6-diphosphate(FDP) on the elevated intrasynaptosomal [Ca²⁺]_i induced by excitatory amino acids(EAA). METHODS: A rapid method for preparing synaptosomes was used, and intrasynaptosomal free calcium([Ca²⁺]_i) was measured by using the fluorescent indicator quin-2. RESULTS: L-glutamate(Glu, 100 μmol/L), aspartate(Asp, 100 μmol·L^-1), N-methy1-D-aspartate(100 μmol/L) and Glu(50 μmol/L) plus Asp(50 μmol/L) all elevated intrasynaptosomal [Ca²⁺]_i in a dose-dependent manner. Pretreatment with Tet(10, 30, 60 μmol/L), FDP(15, 30, 75, 150 μmol/L), MK-801(10, 20 μmol/L) and Tet(15, 30 μmol/L) plus FDP(15, 30 μmol/L) all attenuated the increase in intrasynaptosomal [Ca²⁺]_i induced by EAAs mentioned as above in a dose-dependent manner, and the effect of Tet plus FDP was most significant. CONCLUSION: Both Tet and FDP inhibited a rise in intrasynaptosomal [Ca²⁺]_i induced by EAAs, which may be one of mechanisms that Tet and FDP pretect cerebral tissues against ischemia injury.     

3x+1问题的若干性质

从一个特殊的角度描述3x 1问题,引入了部分新的概念,建立了3x 1问题的等价命题,得到了关于3x 1问题特别是数列{fk(x)|k∈Z }的一部分性质.     

水稻OsRFP1基因的原核表达与蛋白纯化

以推导的氨基酸序列分析,水稻OsRFP1基因编码一分子量为34.24kDa锌指蛋白。将OsRFP1基因编码区cDNA序列插入到pGEX4T-3载体中构建OsRFP1-gst融合基因的表达载体,并将质粒转化宿主菌大肠杆菌BL21DE3。经IPTG诱导,融合蛋白在BL21DE3细胞中获得表达。利用亲和层析的方法对融合蛋白进行了纯化,SDS-PAGE蛋白电泳显示获得一60kDa的唯一蛋白条带,即OsRFP1-GST融合蛋白。     

DWL-48连续捣固稳定车一号发动机起动系统故障处理

一号发动机是DWL-48捣固车的动力核心,其性能影响很大,一旦出现问题将会直接影响施工进度和线路质量,甚至影响线路的开通和运营。文章分析了DWL-48连续捣固稳定车一号发动机起动系统起动控制电路的原理,并提出了DWL-48连续捣固稳定车一号发动机起动系统故障的常见处理方法。