Enhancement of solubility in <Emphasis Type="Italic">Escherichia coli</Emphasis> and purification of an aminotransferase from <Emphasis Type="Italic">Sphingopyxis</Emphasis> sp. MTA144 for deamination of hydrolyzed fumonisin B<Subscript>1</Subscript>

Background  

Fumonisin B₁ is a cancerogenic mycotoxin produced by Fusarium verticillioides and other fungi. Sphingopyxis sp. MTA144 can degrade fumonisin B₁, and a key enzyme in the catabolic pathway is an aminotransferase which removes the C2-amino group from hydrolyzed fumonisin B₁. In order to study this aminotransferase with respect to a possible future application in enzymatic fumonisin detoxification, we attempted expression of the corresponding fumI gene in E. coli and purification of the enzyme. Since the aminotransferase initially accumulated in inclusion bodies, we compared the effects of induction level, host strain, expression temperature, solubility enhancers and a fusion partner on enzyme solubility and activity.     

双歧杆菌制剂对急性重症胰腺炎感染的治疗作用

目的：观察双歧杆菌制剂对急性重症胰腺炎感染的治疗作用。方法：收治9例急性重症胰腺炎患者投以双歧杆菌制剂,经临床观察及大便细菌培养。结果：双歧杆菌制剂可改善临床症状,细菌培养显示患者肠道双歧杆菌、乳酸杆菌总数明显增加,肠道菌群接近正常比例,结论：双歧杆菌制剂对急性重症胰腺炎合并感染有辅助治疗作用。     

AQP1促进肺动脉平滑肌细胞的增殖与迁移（应作者要求撤稿）

该文应作者要求已撤稿。肺动脉平滑肌细胞（PASMCs）的迁移和增殖是肺动脉重塑进而造成肺动脉高压的主要病理基础。水通道蛋白1（AQP1）具有促进上皮细胞、内皮细胞迁移的作用,但机制不清。由于AQP1也表达于血管平滑肌细胞,推测AQP1可能参与缺氧诱导的PASMCs增殖及迁移。通过PCR和免疫印迹分析,检测AQP的表达以及缺氧对AQP表达水平的影响,并通过细胞迁移以及增殖实验观察AQP1在缺氧诱导的PASMCs迁移与增殖中的作用。AQP1在PASMCs和主动脉平滑肌细胞（AoSMCs）均表达,但缺氧只增加PASMCs中AQP1的表达,以及促进PASMCs的迁移与增殖。敲除AQP1可抑制PASMCs的增殖以及缺氧诱导的细胞增殖和迁移。过表达AQP1促进PASMCs的增殖和迁移。缺氧促进β联蛋白在PASMCs内的表达。敲除β联蛋白后,抑制AdAQP1所介导的PASMCs迁移与增殖。这些结果表明,缺氧可促进AQP1在肺动脉内的表达,AQP1可通过β联蛋白对PASMCs的增殖和迁移进行调节。     

秘鲁民间草药及其与中草药种类之比较

作者通过实地考察,论述了秘鲁丰富的民族植物学和民间草药知识,并根据收集到的有关资料对秘鲁民间草药和中草药的种类进行比较分析,为进一步开发药用植物资源和研制新药提供参考。     

Immobilization of cellulase from newly isolated strain Bacillus subtilis TD6 using calcium alginate as a support material

Bacillus subtilis TD6 was isolated from Takifugu rubripes, also known as puffer fish. Cellulase from this strain was partially purified by ammonium sulphate precipitation up to 80% saturation, entrapped in calcium alginate beads, and finally characterized using CMC as the substrate. For optimization, various parameters were observed, including pH maximum, temperature maximum, sodium alginate, and calcium chloride concentration. pH maximum of the enzyme showed no changes before and after immobilization and remained stable at 6.0. The temperature maximum showed a slight increase to 60 °C. Two percent sodium alginate and a 0.15 M calcium chloride solution were the optimum conditions for acquisition of enzyme with greater stability. K (m) and V (max) values for the immobilized enzyme were slightly increased, compared with those of free enzyme, 2.9 mg/ml and 32.1 μmol/min/mL, respectively. As the purpose of immobilization, reusability and storage stability of the enzyme were also observed. Immobilized enzyme retained its activity for a longer period of time and can be reused up to four times. The storage stability of entrapped cellulase at 4 °C was found to be up to 12 days, while at 30 °C, the enzyme lost its activity within 3 days.     

利用脊髓灰质炎病毒5'NCR和RNA聚合酶基因可提高外源基因表达

将含脊髓灰质炎病毒 (PV)RNA聚合酶的不同长度基因片段克隆到载体 pSG5质粒上 ,分别构建了 4个表达RNA聚合酶的质粒。体外转录实验证明 ,pSG5 POL1 99和 pSG5 POL2 0 3质粒转染细胞的提取物促进了特异的RNA转录 ,表明两质粒可表达RNA聚合酶。将PV的 5'NCR序列插在载体 pGREENLANTERN 1的CMV启动子下游 ,构建了 pGREENLANTERN 1 5'NCR质粒 ;用 LacZ基因替换GFP基因分别插入到PGREENLANTERN 1和pGREENLANTERN 1 5'NCR质粒上 ,构建成 pLacZLANTERN 1和 pLacZLANTERN 1 5'NCR质粒。表达RNA聚合酶的质粒与 pLacZ 5'NCR调控表达报告基因的质粒共转染 ,明显提高了报告基因的表达水平 ,表明PV的表达调控元件和RNA聚合酶基因可用于构建外源基因高效表达载体。     

野生大熊猫与放牧家畜的活动格局比较

活动格局是动物内在机制和环境作用所表现出来的昼夜活动节律及其活动水平的行为生态特征,影响着动物的能量代谢能力、觅食行为策略和进化适应。通过内置活动传感器的GPS颈圈,于2010—2012年在四川卧龙国家级自然保护区的"核桃坪"及其毗邻区域,采集了野生大熊猫和放牧家畜的大量活动数据。分别选择3只成年大熊猫和3个马群的代表性个体作为样本,引入活动强度、活动时间百分率、活动时间片段率和活动片段时长等指标进行了两者之间的比较,以揭示大熊猫和放牧家畜在时间利用方面的内在特征。结果表明:野生大熊猫和放牧家畜在活动强度、活动时间百分率和活动时间片段率等方面都具有极显著性差异(P0.0001),仅两者之间的活动片段时长无明显的统计学意义(P=0.4107)。野生大熊猫表现为活动水平低、活动时间少、活动片段率高和活动片段时长短等特征的活动格局,且不同月份(季度)之间变化较大(P0.0001);放牧家畜则呈现出相异的时间利用规律,即活动水平高、活动时间多、活动时间片段率稍低和活动片段时长略长等特性。不同的时间利用规律和不同的空间利用模式,造成动物之间对栖息地、食物资源和伴生动物的利用方式、影响强度和空间分布的截然不同。因而,合理规划和管控放牧家畜的散养区域与数量,是自然保护管理与社区经济发展相协调的有效途径之一。     

Detection of viral infection by immunofluorescence in formalin-fixed tissues, pretreated with trypsin

The presence of viral antigen in sections from formalin-fixed and paraffin-embedded human tissues was demonstrated by trypsin digestion followed by direct or indirect immunofluorescence. The specimens may be used for retrospective diagnosis. The immunofluorescence technique has to be adapted to the suspected virus infection on the basis of previous histopathologic study. Variations of trypsin concentration time and temperature of incubation, expose different viral antigens and have to be previously tested for each unknown system. For measles virus detection in lung a stronger digestion has to be applied as compared to adenovirus or respiratory disease viruses in the same tissue. Flavivirus in liver tissue needs a weaker digestion. The reproducibility of the method makes it useful as a routine technique in diagnosis of virus infection.     

Use of an immunoenzymatic reaction in the determination of the genetic character of poliovirus samples

Characterization of poliovirus strains by an enzyme immunoassay (EIA). An enzyme immunoassay performed with polyclonal antisera to poliovirus types 1, 2 and 3 absorbed with heterologous strains of the same types was used for the characterization of poliovirus field isolates. The assay allowed the identification of 74 (93.6%) out of 79 isolates as wild or vaccine-like strains. Applications of EIA for the study of polioviruses are discussed.