用指纹图谱评价环境样本DNA的提取效果

研究了DNA指纹图谱技术在评价环境样本DNA提取效果方面的应用。采用 3种DNA提取方法提取垃圾渗滤水和活性污泥中的微生物DNA ,并用ARDRA和RISA图谱加以评价。实验结果表明 ,RISA图谱分析法可以作为评估DNA提取效果的有效手段。     

野生与栽培黄花蒿净光合速率对光强和CO2浓度的响应

比较了相同种源的野生和栽培黄花蒿(Artemisia annua L.)净光合速率对光强和CO2浓度的响应特性。结果表明,野生和栽培黄花蒿的光饱和点(LSP)分别为1 183和1 564μmol m-2s-1,光补偿点(LCP)为17和18μmol m-2s-1,最大净光合速率(Pmax)为18.78和22.38μmol m-2s-1,表观量子效率(AQY)为0.08和0.075μmol m-2s-1,表明黄花蒿的光合能力强,能够利用很高的光强,且对弱光的适应性也较强。栽培黄花蒿的Pmax、LSP和最大羧化速率(Vcmax)显著高于野生黄花蒿,两者的LCP、不包括光下呼吸的CO2补偿点、AQY、光下呼吸速率和最大电子传递速率(Jmax)差异不显著。强光下栽培黄花蒿主要通过提高Vcmax和Jmax等来增强光合能力,强的光合能力有利于黄花蒿的生长,因此在人工栽培黄花蒿的过程中应选择阳光充足的开阔生境。     

同型半胱氨酸对大鼠血管平滑肌细胞增殖的作用

血中同型半胱氨酸（ｈｏｍｏｃｙｓｔｅｉｎｅ,ＨＣＹ）浓度的升高已成为动脉粥样硬化发生的一个独立危险因子．为进一步阐明ＨＣＹ促进血管平滑肌细胞（ｖａｓｃｕｌａｒｓｍｏｏｔｈｍｕｓｃｌｅｃｅｌｓ,ＶＳＭＣｓ）增殖,从而引起动脉粥样硬化发生的机理．本实验采用细胞计数、３Ｈ－ＴｄＲ参入、细胞周期分析、Ｎｏｒｔｈｅｒｎ杂交方法证明,一定剂量的ＨＣＹ可促进离体培养的ＷＫＹ大鼠血管平滑肌细胞增殖,使其ＤＮＡ合成增加,细胞周期中Ｓ期细胞所占比例增加４３％,并促进ｃ－ｍｙｃ与ｃ－ｆｏｓ原癌基因ｍＲＮＡ表达增加．提示ＨＣＹ可能通过促进ＶＳＭＣｓ增殖而诱发动脉粥样硬化     

Determination of cefazedone in human plasma by high performance liquid chromatography–tandem mass spectrometry: Application to a pharmacokinetic study on Chinese volunteers

A rapid, sensitive and simple high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method was developed for determination of cefazedone in human plasma using metronidazole as internal standard (IS). The chromatographic separation was achieved on an Ultimate XB-CN column (2.1 mm × 150 mm, 5 μm) with an isocratic mobile phase of acetonitrile and 20 mM ammonium acetate in 0.1% formic acid in water (15:85, v/v). Detection was performed using electrospray ionization in positive ion multiple reaction-monitoring mode (SRM), monitoring the transitions m/z 548.2 → 344.1 for cefazedone and m/z 172.2 → 128.1 for IS. Calibration curves were linear over a wide range of 0.20–401.12 μg/mL for cefazedone in plasma. The lower limit of quantification (LLOQ) was 0.20 μg/mL. The intra- and inter-day precisions were less than 7.2%. The average recovery of cefazedone was 90.8–91.0%. The validated method was successfully applied to the pharmacokinetic study of cefazedone in Chinese healthy volunteers following intravenous (IV) administration of 500, 1000 and 2000 mg cefazedone injection.     

鼎突多刺蚁群体结构和生活史的研究

本文报告了鼎突多刺蚁(Polyrhachis vicina Roger)的群体结构和生活史。通过研究表明,鼎突多刺蚁一年发生一代,以蚁后、雄蚁、工蚁、幼虫和卵越冬。卵和幼虫在冬天发育停滞(或极慢)。到了春天,随着气温的上升,卵和幼虫又恢复正常发育。据室内人工饲养观察,卵的发育历期为23.8±2.5天(平均温度26℃)幼虫为20.4±4.4天(26℃),工蚁蛹为19.8±5.5天(27℃)。成长工蚁在5—11月出现;8—11月,雄蚁从蛹中羽化;10月,雌蚁从蛹中羽化。雌蚁分飞交尾后,进入邻近蚁巢或回到原巢,脱翅成为蚁后。蚁巢内存在着多后现象。     

“蛋白质与酶工程”教学的课程思政探索与实践

蛋白质与酶工程是生物技术专业的核心、必修课程,在专业人才培养体系中具有重要地位。文中以教育部颁布的《高等学校课程思政建设指导纲要》为依据、结合专业及课程特色,科学设定教学目标,深入挖掘课程思政教育元素,从融入内容、方法路径及评价等方面进行了课程思政教学改革的探索和实践。通过精心开展教学设计,利用对分课堂、以学生为中心,从讲故事、谈生活、说案例、议热点、读文献、做训练入手,激发并培养学生的科学精神、公民品格、全球视野、生态文明、法治意识、家国情怀和文化自信素养,促进课程思政教育有机融入教学全过程,实现课程育人目标的同时推动教学卓越。     

Structural and biochemical characterization of ZhuI aromatase/cyclase from the R1128 polyketide pathway

Aromatic polyketides comprise an important class of natural products that possess a wide range of biological activities. The cyclization of the polyketide chain is a critical control point in the biosynthesis of aromatic polyketides. The aromatase/cyclases (ARO/CYCs) are an important component of the type II polyketide synthase (PKS) and help fold the polyketide for regiospecific cyclizations of the first ring and/or aromatization, promoting two commonly observed first-ring cyclization patterns for the bacterial type II PKSs: C7-C12 and C9-C14. We had previously reported the crystal structure and enzymological analyses of the TcmN ARO/CYC, which promotes C9-C14 first-ring cyclization. However, how C7-C12 first-ring cyclization is controlled remains unresolved. In this work, we present the 2.4 ? crystal structure of ZhuI, a C7-C12-specific first-ring ARO/CYC from the type II PKS pathway responsible for the production of the R1128 polyketides. Though ZhuI possesses a helix-grip fold shared by TcmN ARO/CYC, there are substantial differences in overall structure and pocket residue composition that may be important for directing C7-C12 (rather than C9-C14) cyclization. Docking studies and site-directed mutagenesis coupled to an in vitro activity assay demonstrate that ZhuI pocket residues R66, H109, and D146 are important for enzyme function. The ZhuI crystal structure helps visualize the structure and putative dehydratase function of the didomain ARO/CYCs from KR-containing type II PKSs. The sequence-structure-function analysis described for ZhuI elucidates the molecular mechanisms that control C7-C12 first-ring polyketide cyclization and builds a foundation for future endeavors into directing cyclization patterns for engineered biosynthesis of aromatic polyketides.     

Pregnane, coumarin and lupane derivatives and cytotoxic constituents from Helicteres angustifolia

2alpha,7beta,20alpha-Trihydroxy-3beta,21-dimethoxy-5-pregnene (1), 6,7,9alpha-trihydroxy-3,8,11alpha-trimethylcyclohexo-[d,e]-coumarin (2), 3beta-hydroxy-27-benzoyloxylup-20(29)-en-28-oic acid (3), and 3beta-hydroxy-27-benzoyloxylup-20(29)-en-28-oic acid methyl ester (4), along with 24 known compounds were isolated and structurally characterized from roots and aerial parts of Helicteres angustifolia (Sterculiaceae). In a preliminary bioassay, the two cucurbitacin derivatives, cucurbitacin D and J exhibited significant inhibitory activities against the growth of both hepatocellular carcinoma BEL-7402 cells and malignant melanoma SK-MEL-28 cells in vitro.     

Phosphorylation of a 25 kDa protein is induced by thermostable direct hemolysin of Vibrio parahaemolyticus

Thermostable direct hemolysin (TDH) is a possible virulence factor produced by Vibrio parahaemolyticus. Although TDH has a variety of biological activities, including hemolytic activity, the biochemical mechanism of action remains uncertain. Here we analysed biochemical events, especially phosphorylation, caused by TDH in erythrocytes, and found that TDH caused significant phosphorylations of proteins on erythrocyte membrane. Phosphorylation of proteins was studied using γ-³²P ATP and SDS-PAGE. A number of protein kinase inhibitors were tested, to determine which types of kinases were involved in the phosphorylation events. TDH induced the phosphorylation of two proteins on membranes of human erythrocyte that are sensitive to TDH. The estimated molecular weight of these proteins was 25 and 22.5 kDa. Interestingly, the 22.5 kDa, but not the 25 kDa protein, was phosphorylated on the membrane of TDH-insensitive (resistant) horse erythrocytes. Moreover, a mutant TDH (R7), which retained binding ability but lost hemolytic activity, also phosphorylated only the 22.5 kDa protein on human erythrocyte membranes. Among the protein kinase inhibitors used the protein kinase C inhibitors, (staurosporine and calphostin C) showed marked inhibition of phosphorylation of 25 kDa protein. In addition to phosphorylation, these protein kinase C inhibitors suppresssed hemolysis by TDH. These results indicate that the phosphorylation of the 25 kDa protein seems to be essential for the hemolysis by TDH after it binds to erythrocyte membranes.     

Effects of size,neighbors, and site condition on tree growth in a subtropical evergreen and deciduous broad‐leaved mixed forest,China

Successful growth of a tree is the result of combined effects of biotic and abiotic factors. It is important to understand how biotic and abiotic factors affect changes in forest structure and dynamics under environmental fluctuations. In this study, we explored the effects of initial size [diameter at breast height (DBH)], neighborhood competition, and site condition on tree growth, based on a 3‐year monitoring of tree growth rate in a permanent plot (120 × 80 m) of montane Fagus engleriana–Cyclobalanopsis multiervis mixed forest on Mt. Shennongjia, China. We measured DBH increments every 6 months from October 2011 to October 2014 by field‐made dendrometers and calculated the mean annual growth rate over the 3 years for each individual tree. We also measured and calculated twelve soil properties and five topographic variables for 384 grids of 5 × 5 m. We defined two distance‐dependent neighborhood competition indices with and without considerations of phylogenetic relatedness between trees and tested for significant differences in growth rates among functional groups. On average, trees in this mixed montane forest grew 0.07 cm year^?1 in DBH. Deciduous, canopy, and early‐successional species grew faster than evergreen, small‐statured, and late‐successional species, respectively. Growth rates increased with initial DBH, but were not significantly related to neighborhood competition and site condition for overall trees. Phylogenetic relatedness between trees did not influence the neighborhood competition. Different factors were found to influence tree growth rates of different functional groups: Initial DBH was the dominant factor for all tree groups; neighborhood competition within 5 m radius decreased growth rates of evergreen trees; and site condition tended to be more related to growth rates of fast‐growing trees (deciduous, canopy, pioneer, and early‐successional species) than the slow‐growing trees (evergreen, understory, and late‐successional species).