视黄醇结合蛋白的分子生物学

视黄醇结合蛋白 (RBP)是维生素A(VitA)的运载蛋白 ,结构上为疏水小分子结合蛋白家族的成员。视黄醇结合蛋白在肝脏中合成并释放入血液后 ,通过与视黄醇 (ROH)、甲状腺素运载蛋白 (TTR)及细胞表面受体相互作用 ,在VitA的储存、代谢、转运到周围靶器官中发挥重要功能。本文从基因结构与表达、构效关系及临床意义等方面介绍了视黄醇结合蛋白的分子生物学。     

胃息肉与幽门螺杆菌感染关系研究

目的探讨胃息肉与幽门螺杆菌（Helicobacter pylori,H.pylori）感染关系。方法对1218例胃息肉同时进行H．pylori检查患者进行回顾性分析,分析胃息肉患者H.pylori感染率、胃息肉部位与H.pylori感染关系、胃息肉病理类型与H.pylori感染关系。结果发现胃息肉Hpylori感染患者532例,Hpylori感染率为43．7％。男性胃息肉患者H.pylori感染率为47．5％（216／455）,女性Hpriori感染率感染率为41．4％（316／763）（P〉0．05）,年龄〈20岁、20～39岁、40—59岁和≥60岁胃息肉H.priori感染率分别为41．7％、44．7％、41．6％和47．2％（P〉0．05）;胃窦胃角息肉H.pylori感染率高于其他部位（胃体、胃底和贲门）（P〈0．05）;炎性和增生性胃息肉H.priori感染率高于胃底腺和腺瘤性息肉（P〈0．05）。结论H.pylori感染可能与部分胃息肉发生有一定关系,需要进一步深入研究胃息肉的发生机制。     

Cell death induced by Pteris semipinnata L. is associated with p53 and oxidant stress in gastric cancer cells

In this study, we demonstrated that Ent-11alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5F) had stronger cytotoxicity against MKN-45, a gastric cancer cell line bearing wild-type p53 than MKN-28, another gastric cancer cell line containing missense mutation in p53. The rapid increase of ROS level was involved in the mechanism of cytotoxicity. Classical features of apoptosis induced by 5F were observed in MKN-45 cells only or more significant in MKN-45 cells than MKN-28 cells. Translocation of Bax from cytosol to mitochondria, reduction of delta psi m and DNA fragmentation were induced by 5F in the p53-dependent manner. We conclude that the expression of Bax and its downstream molecules requires the presentation of a wild-type p53 in the cells treated by 5F.     

Engineered Pentafunctional Minicellulosome for Simultaneous Saccharification and Ethanol Fermentation in Saccharomyces cerevisiae

Several yeast strains have been engineered to express different cellulases to achieve simultaneous saccharification and fermentation of lignocellulosic materials. However, successes in these endeavors were modest, as demonstrated by the relatively low ethanol titers and the limited ability of the engineered yeast strains to grow using cellulosic materials as the sole carbon source. Recently, substantial enhancements to the breakdown of cellulosic substrates have been observed when lytic polysaccharide monooxygenases (LPMOs) were added to traditional cellulase cocktails. LPMOs are reported to cleave cellulose oxidatively in the presence of enzymatic electron donors such as cellobiose dehydrogenases. In this study, we coexpressed LPMOs and cellobiose dehydrogenases with cellobiohydrolases, endoglucanases, and β-glucosidases in Saccharomyces cerevisiae. These enzymes were secreted and docked onto surface-displayed miniscaffoldins through cohesin-dockerin interaction to generate pentafunctional minicellulosomes. The enzymes on the miniscaffoldins acted synergistically to boost the degradation of phosphoric acid swollen cellulose and increased the ethanol titers from our previously achieved levels of 1.8 to 2.7 g/liter. In addition, the newly developed recombinant yeast strain was also able to grow using phosphoric acid swollen cellulose as the sole carbon source. The results demonstrate the promise of the pentafunctional minicellulosomes for consolidated bioprocessing by yeast.     

模拟失重对大鼠心肌力学与生物化学的影响

观察为期４周模拟失重对大鼠心肌收缩性能与收缩蛋白性质的影响,发现模拟失重大鼠左心室乳头肌等长收缩的力学特征发生下列变化：发展张力峰值降低２９％（Ｐ〈０．０１）;达到张力峰值的时间延长１０％（Ｐ〈０．０５）;舒张一半的时间缩短１１％,但未达到显著水平（Ｐ〉０．０５）。心肌力学参数的这些变化表明模拟失重使大鼠心肌收缩性能降低。进一步研究显示,模拟失重大鼠左室心肌肌原纤维Ｃａ＾２＋,Ｍｇ＾２＋－ＡＴＰ酶     

Cdc42和球形肌动蛋白在卵母细胞胞质分裂中的定位分析

研究活性Cdc42与球形肌动蛋白(G-actin)在爪蟾卵母细胞胞质分裂中的定位关系。分别用GFP-wGBDmRNA与罗丹明-594-微管蛋白、Alexa-488-球形肌动蛋白与罗丹明-594-微管蛋白、GFP-wGBDmRNA与Alexa-594-球形肌动蛋白共同显微注射爪蟾卵母细胞。利用共聚焦显微镜,时间延迟摄影方法,分别观察活体卵母细胞中活性Cdc42、球形肌动蛋白在胞质分裂过程中的定位,以及活性Cdc42与球形肌动蛋白在胞质分裂中的定位关系。在卵母细胞胞质分裂中,活性Cdc42与球形肌动蛋白存在空间上共定位现象,并且在时相上具有一致性。结果提示活性Cdc42和球形肌动蛋白在卵母细胞胞质分裂过程中密切相关。     

Microbial biosensors: a review

A microbial biosensor is an analytical device which integrates microorganism(s) with a physical transducer to generate a measurable signal proportional to the concentration of analytes. In recent years, a large number of microbial biosensors have been developed for environmental, food, and biomedical applications. Starting with the discussion of various sensing techniques commonly used in microbial biosensing, this review article concentrates on the summarization of the recent progress in the fabrication and application of microbial biosensors based on amperometry, potentiometry, conductometry, voltammetry, microbial fuel cell, fluorescence, bioluminescence, and colorimetry, respectively. Prospective strategies for the design of future microbial biosensors will also be discussed.     

县域农业主导产业结构生态适宜性评价及其发展预测

基于生态适宜性“三基点”理论,采用动态赋权和拟合的方法,建立县域农业主导产业结构生态适宜性评价指标体系,并以山东省章丘市为例,对其县域农业主导产业结构生态适宜性进行评价.结果表明： 在有限的农业生态资源下,2005-2010年,章丘市4种农业主导产业的生态适宜性综合指数呈上升趋势;2011-2015年,则呈下降趋势,其中,2015年油料作物和水果的生态适宜性综合指数出现负值.对章丘市的应用研究证实了本文提出的县域农业主导产业结构生态适宜性评价方法的有效性及预测模型的合理性.     

烟酰胺在原代培养的猪前体脂肪细胞增殖分化中的作用

为研究烟酰胺(Nicotinamide,NAM)在原代培养的猪前体脂肪细胞增殖分化中的作用,探讨其作用的分子机制,用不同浓度(0-500μmol/L)的NAM处理猪前体脂肪细胞。MTT和油红O染色及提取法检测结果表明:在不同的作用时间内,与对照组相比,100-500μmol/L的NAM均可以促进猪前体脂肪细胞的增殖分化,随着NAM浓度的增加,其对前体脂肪细胞增殖分化的促进作用逐渐上升,当浓度为300μmol/L时达到高峰,即300μmol/L NAM的促进效果最为显著(P<0.05);随后,400和500μmol/L NAM的促进作用逐渐减弱。RT-PCR法分析结果表明,Sirt1 mRNA表达显著下降(P<0.05),而其靶基因FoxO1和脂肪细胞分化标志基因PPARγ2、C/EBPα mRNA表达量明显升高(P<0.01),aP2和LPL表达也显著增加(P<0.05)。表明NAM是Sirt1的一个有效抑制剂,它可能通过抑制Sirt1的表达来促进猪前体脂肪细胞增殖和分化。