ERK介导的炎性反应参与肾缺血再灌注损伤

目的研究小鼠肾缺血再灌注损伤的发病机制。方法建立小鼠肾缺血再灌注损伤模型。12只雄性C57BL／6随机分为2个组（n=6）,分别为假手术组（Sham）,肾缺血再灌注损伤模型组（IRI）。IRI组血管夹夹闭左肾动脉,置于32℃温箱后1h松开血管夹,去除右肾。Sham组操作同上,但不夹闭左肾动脉。再灌注24h后处死小鼠,收集血清和肾脏标本。测定血清肌酐（Cr）和血尿素氮（BUN）。PAS染色后显微镜下观察肾脏形态学变化,Western印迹分析ERK、p-ERK的表达,PCR检测MCP-1、IFN-γ。结果与假手术组（Sham）相比,IRI组血清肌酐、血尿素氮明显升高,病理检查可见肾脏内肾小管上皮细胞明显肿胀坏死、蛋白管型形成明显,还可观察到炎性细胞浸润明显增加。ERK、p-ERKWestern印迹结果PCR显示MCP-1、TNF-α也明显上调,但ERK表达不变。结论在肾缺血再灌注中,ERK激活介导的炎性后府可能参与了肾扣伤。     

Long-term effects of simulated acid rain stress on a staple forest plant, Pinus massoniana Lamb: a proteomic analysis

At present, acid rain has become one of the top ten global environmental issues. Acid rain causes slower growth, injury, or decline of forests. Some dramatic effects on forests have been observed in south China since the late 1970s and the situation is deteriorating. We carried out a comparative proteomic analysis on Pinus massoniana Lamb, a staple tree species widely distributed in middle and south China to gain a better understanding of tree response to acid rain at molecular level. Two-year-old P. massoniana saplings were treated with simulated AR (SiAR) or control solution, respectively, for 8 months. The changes in total protein profile of P. massoniana leaves were studied using two-dimensional differential gel electrophoresis (2D-DIGE). Among the total protein spots reproducibly detected on each gel, 65 spots representing 28 proteins were identified to be differentially regulated. These proteins were annotated in various biological functions, such as photosynthesis and energy metabolism, secondary metabolism, protein stability, amino acid and nitrogen metabolism and defense. Down-regulation of four key enzymes in the Calvin cycle identified that biomass loss by SiAR was mainly due to the inhibition of carbon fixation. Primary energy metabolisms involved in sucrose biosynthesis, glycolytic pathway and Krebs cycle, etc., were also disturbed after SiAR treatment. Specifically, most of up-regulated proteins were related to secondary metabolism, protein stability and defense, suggesting that in response to SiAR stress, plants started a variety of metabolic pathways to prevent cells from damage. Different from the herbaceous plants suffering SiAR, it revealed that secondary metabolites in P. massoniana play pivotal roles against SiAR. Protemoic techniques were demonstrated a reliable and robust tool to expand our understanding of differentially expressed proteins associated with acid rain stress on P. massoniana. Functional analysis of these proteins further revealed biochemical and physiological basis of the plant in response to acid rain and would provide strategies for breeding new acid rain tolerant tree species. To our knowledge, it is the first proteome report on the forest plant suffering long-term acid rain stress.     

Separation,antitumor activities,and encapsulation of polypeptide from Chlorella pyrenoidosa

Chlorella pyrenoidosa is a unicellular green algae and has been a popular foodstuff worldwide. However, no reports on the antitumor peptides from such a microalgae are available in the literature. In this study, using low‐temperature high‐pressure extraction, enzymatic hydrolysis, ion exchange, and gel filtration chromatography, we separated a polypeptide that exhibited inhibitory activity on human liver cancer HepG2 cells, and named the polypeptide CPAP (C. pyrenoidosa antitumor polypeptide). Furthermore, the micro‐ and nanoencapsulation of CPAP were investigated by using two methods: complex coacervation and ionotropic gelation. The in vitro release tests revealed that CPAP was well preserved against gastric enzymatic degradation after micro/nanoencapsulation and the slowly controlled release in the intestine could be potentially achieved. These results suggest that CPAP may be a useful ingredient in food, nutraceutical, and pharmaceutical applications. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:681–687, 2013     

结核分枝杆菌硫醇乙酰基转移酶基因敲除株的构建及其生物学特性分析

为探索硫醇乙酰基转移酶(mycothiol acetyltransferase,MshD)在结核分枝杆菌中的生物学特性,本实验利用噬菌体为载体的同源重组技术,构建结核分枝杆菌mshD基因敲除株、mshD基因回补株,用实时定量聚合酶链反应(real time-quantitative polymerase chain reaction, RT-qPCR)对所构建的菌株进行验证。分别收集H37Ra野生株、mshD基因敲除株、mshD基因回补株对数生长期菌液各5 mL, 离心收集菌体并培养,以观察菌落形态、生物膜形成及生长曲线测定;用5 mmol/L H₂O₂、0.05% SDS,50 ℃热激及低氧条件下分别处理基因敲出菌株和野生菌株,将菌液进行10倍梯度稀释,培养4～6周后检测抗胁迫能力并计算存活率。结果显示, 与野生株H37Ra相比,mshD基因敲除株菌落褶皱减少且菌落偏小,生长趋势较为缓慢;生物膜形成所需时间增长且褶皱明显减少;抗逆能力下降,存活率略低于野生株和回补株。揭示了mshD基因对结核分枝杆菌的生长具有重要作用,为进一步揭示该基因的功能和作用机制奠定了基础。