具有杀镰孢菌素合成功能基因菌株的筛选与鉴定

在NCBI数据库中搜索已知多黏类芽孢杆菌基因组中分别编码Fusaricidin合成酶3个NRPS功能区段的核苷酸保守序列,利用Primer5.0软件设计3对引物,对供试的95个细菌菌株进行PCR检测,筛选到1株阳性菌株T99,其3对引物扩增产物的测序结果表明,所得3个功能片段核苷酸序列与多黏类芽孢杆菌SC2和M1的Fusaricidin合成酶基因序列的一致性分别为99％、97％和99％,说明菌株T99基因组中具有Fusaricidin合成相关功能基因.结合形态特征及培养性状、生理生化特性和16SrDNA序列同源性分析的结果,将菌株T99鉴定为多黏类芽孢杆菌.     

Winter spatial distribution of fish larvae assemblages relative to the hydrography of the waters surrounding Taiwan

The aim of this study was to investigate the species composition and distribution of fish larvae in relation to hydrographic conditions in the waters surrounding Taiwan Island (TI) in February 2003. In total, 242 kinds of fish larvae belonging to 127 genera and 75 families were recognized. Among these, 109 taxa were identified to the family or genus level, others to the species level. The 12 predominant types, which constituted 71% of the total fish larvae, were Engraulis japonica, Scomber sp., Diaphus spp., Benthosema pterotum, Carangoides ferdau, Embolichthys mitsukurii, Maurolicus sp., unidentified Myctophidae, Gonostoma gracile, Trichiurus lepturus, unidentified Gobiidae, and Myctophum asperum. The distribution of fish larvae showed a clear association with water masses around TI, with higher abundances and lower species richness northwest of TI where the China Coastal Current prevails, and lower abundances and higher species diversity east of TI where the Kuroshio Current dominates. Cluster analysis distinguished three station groups and four species groups, and the distribution patterns of fish larvae also corresponded to hydrographic conditions. The total abundances of fish larvae and eight of the 12 predominant taxa showed significant and positive correlations with zooplankton abundance, which suggests that food source might be a key factor determining the abundance and distribution of fish larvae during the winter.     

Identifying Hfq-binding small RNA targets in Escherichia coli

The Hfq-binding small RNAs (sRNAs) have recently drawn much attention as regulators of translation in Escherichia coli. We attempt to identify the targets of this class of sRNAs in genome scale and gain further insight into the complexity of translational regulation induced by Hfq-binding sRNAs. Using a new alignment algorithm, most known negatively regulated targets of Hfq-binding sRNAs were identified. The results also show several interesting aspects of the regulatory function of Hfq-binding sRNAs.     

神经系统中内源性硫化氢的研究进展

神经系统内源性的硫化氢（H2S）被认为是一种神经调质,其可以提高神经元N-甲基-D-天冬氨酸（NMDA）受体调节的反应,易化海马长时程增强（LTP）的产生,从而调节学习和记忆;诱发星形细胞产生钙波从而介导神经元及星形胶质细胞间的信号传递;增加抗氧化剂谷胱甘肽水平、抑制和清除神经系统内的多种氧化性物质等,具有广泛的生理作用。同时,H2S也参与了Alzheimer病、热性惊厥、脑卒中、Down＇s综合征等神经系统疾病的病理生理过程。     

歌德与生物学

歌德（Goethe）是德国古典文学和民族文学的杰出代表,也是世界文学史上最杰出的作家之一。青年时代,他的书信体小说《少年维特之烦恼》使他获得了巨大的成功;而他晚年的作品《浮士德》则是他一生丰富的思想总结和艺术探索的结晶,因而与荷马史诗、但丁的《神曲》和莎士比亚的《哈姆雷特》并列为欧洲文学的四大古典名著。歌德在世界文学史上的重要地位是毋庸置疑的,但是他在生物学上的重要贡献就鲜为人知了。     

鲤肠道正常菌群的研究

本实验用稀释滴种的定量方法,对淡水养殖地中健康鲤肠道内的１０种菌群进行了定性、定量分析,并对结果进行统计学处理,得到鲤肠菌群的一些生理值。结果表明鲤肠道中需氧、兼性厌氧优势菌是气单胞菌和酵母菌,厌氧优势菌是拟杆菌。对不同时间、不同温度条件下同一养殖池中鲤肠道菌群的测定结果比较表明：葡萄球菌、假单胞菌差异显著（ｐ＜０．０５）,气单胞菌、大肠杆菌、需氧芽胞杆菌、酵母菌、乳酸杆菌、双歧杆菌、拟杆菌、梭状芽胞杆菌差异不显著（ｐ＞０．０５）,表明该８种菌群在鲤肠道中的菌数处于相对稳定状态,属于肠道正常菌群。     

PCR检测淋球菌的探讨

多聚酶链反应（ＰＣＲ）具有灵敏度高,特异性强,快速高效的特点,在病原微生物检测领域有广阔的前景。本文对４０８例疑似淋病患者的泌尿生殖道分泌物作了ＰＣＲ检测淋球菌的探索,结果１７０例阳性,占４１．７％,而培养阳性（２１．６％）,ＰＣＲ法显著高于培养法（Ｐ＜０．０１）。     

猫皮层体感Ⅱ区内脏伤害感受神经元的电生理特性及形态特征

应用胞内记录和标记技术,观察了猫皮质第Ⅱ感觉区内脏大神经代表区的神经元对电刺激内脏大神经反应诱发反应及形态特征。结果表明,在２５１个记录单位中,有１０９个为内脏伤害性感受神经元,其诱发反应分为兴奋性、抑制性及混合性三类。在形式上ＩＳＰＳ及ＥＰＳＰ－ＩＰＳＰ序列反应较多。对其中２１个神经元用神经生物素进行细胞内电泳标记,显示细胞的形态特点是胞体较小,分布于皮质Ⅱ、Ⅲ、Ⅴ层,其中兴奋性和神经元形态多为     

Ricin A chain reaches the endoplasmic reticulum after endocytosis

Ricin is a potent ribosome inactivating protein and now has been widely used for synthesis of immunotoxins. To target ribosome in the mammalian cytosol, ricin must firstly retrograde transport from the endomembrane system to reach the endoplasmic reticulum (ER) where the ricin A chain (RTA) is recognized by ER components that facilitate its membrane translocation to the cytosol. In the study, the fusion gene of enhanced green fluorescent protein (EGFP)-RTA was expressed with the pET-28a (+) system in Escherichia coli under the control of a T7 promoter. The fusion protein showed a green fluorescence. The recombinant protein can be purified by metal chelated affinity chromatography on a column of NTA. The rabbit anti-GFP antibody can recognize the fusion protein of EGFP-RTA just like the EGFP protein. The cytotoxicity of EGFP-RTA and RTA was evaluated by the MTT assay in HeLa and HEP-G2 cells following fluid-phase endocytosis. The fusion protein had a similar cytotoxicity of RTA. After endocytosis, the subcellular location of the fusion protein can be observed with the laser scanning confocal microscopy and the immuno-gold labeling Electro Microscopy. This study provided important evidence by a visualized way to prove that RTA does reach the endoplasmic reticulum.