转座子的起源及其和物种进化的关系

关于转座子的属性及其起源问题现在还没有解决,在这篇论文中,作者经过分析提出了转座子由病毒或逆转录病毒退化而来的观点,并且阐述了转座子与物种进化之间的关系,主要从转座子影响物种适应性和引起基因突变,染色体畸变两个方面进行了说明。     

HIV-1 Tat蛋白定点突变的分子动力学模拟

ＨＩＶ－１Ｔａｔ的Ｃｙｓ富集区,核心区和碱性氨基酸富集区是高度保守的,并且对于Ｔａｔ反式激活作用至关重要。用分子动力学模拟的方法构建了ＨＩＶ－１ Ｔａｔ蛋白在上述３个区域进行定点突变的６种突变体的三维结构,分析了突变体的结构变化,并与实验结果相对照讨论了导致突变体失活的原因。     

反义技术分离筛选抑制Vero细胞非定标性突变的cDNA片段

甲基硝基亚硝基胍（ＭＮＮＧ）可诱发猴肾Ｖｅｒｏ细胞的遗传不稳定,在发生表达改变的表达序列标识（ＥＳＴ）中,筛选到１个片段（片段９）,它的相关基因表达被阻断后,ＭＮＮＧ诱发的非定标突变率显著增高（Ｐ〈０．０５）。表明其相关基因的编码产物具有维持遗传稳定性,抑制哺乳类细胞非定标突变发生的功能。     

地球保护伞的新动向

据英国Nature，2005，437：179报道，地球保护伞臭氧层今年出现新变化：南极上空臭氧空洞持续扩大，空洞面积已超过欧洲面积；同时，其他区域臭氧层开始显现出逐步恢复的迹象。     

综合进化论的发展现状

本文论述了综合进化论的形成和发展的几个主要阶段.着重介绍了综合进化论的发展现状和面临的挑战,并对其研究趋势进行了探讨.     

Improved production of spiramycin by mutant Streptomyces ambofaciens

Strain improvement and medium optimization to increase the productivity of spiramycin were carried out. Of oil tolerant mutant strains screened, one mutant, Streptomyces ambofaciens XC 2-37, produced 9% more spiramycin than the parent strain S. ambofaciens XC 1-29. The effects of soybean oil and propyl alcohol on spiramycin production with S.ambofaciens XC 2-37 were studied. The potency orS. ambofaciens XC 2-37 was improved by 61.8% with addition of 2% soybean oil in the fermentation medium and 0.4% propyl alcohol at 24 hours after incubation. The suitable time for feeding propyl alcohol is at 24 hours after incubation in flask fermentation and at 20 hours after incubation in fermentor fermentation The new process with S. ambofaciens XC 2-37 was scaled up for industrial scale production of spiramycin in a 60 m^3 fermentor in Xinchang Pharmaceutical Factory, Zhejiang Medicine Company, Ltd., China, and the potency and productivity of fermentation were improved by 42.9%.     

挑战水污染

据世界卫生组织报道,人类80％的疾病与水有关,并将不洁饮水列为人类健康的十大威胁之一     

电场辐射对南美白对虾幼虾抗逆性影响的研究

分别用不同强度的高压静电场和高压脉冲电场以及两个电场联合作用对南美白对虾幼虾进行处理,对南美白对虾幼虾在少氧状态48h成活率和对盐度突变的适应性进行了实验观测。结果表明一定的电场辐射可以改变南美白对虾幼虾的抗逆性,其作用效果与电场的类型和频率都有关,且适当提高频率作用效果会更好。实验发现在高压静电场(场强:4.0kV/cm,作用时间:4min)与高压脉冲电场(场强:1.5kV/cm、频率:120Hz,作用时间:4min)联合作用时,效果比电场单独作用时要好。对电场辐射对幼虾盐度突变适应性影响的实验数据采用T检验,配对分析进行了统计学分析。由统计结果可知,df=15,P=0.000,按α=0.05的水平,拒绝检验假设,说明电场处理后幼虾对盐度突变的适应能力有改善。     

人猿超科较旧大陆猴Fractalkine基因存在30bp缺失突变

观察Fractalkine从旧大陆猴向人猿超科进化过程中基因的进化规律,为研究Fractalkine基因的进化和免疫学功能演变关系提供理论和实验基础,先用简并引物PCR(Degenerated PCR)法分别扩增Fractalkine的3个外显子,其产物经琼脂糖凝胶回收、纯化后测序,然后用BioEdit,Clustal及DNAStar软件拼接、分析各物种间基因序列的差异.发现人猿超科较旧大陆猴Fracta-lkine基因除了有散在的点突变外,在其粘蛋白样区还有一明显的30个核苷酸的缺失突变,并对突变的可能机制及其对Fractalkine可能的功能影响进行讨论.     

Importance of NPA motifs in the expression and function of water channel aquaporin-1

The asparagine-proline-alanine sequences (NPA motifs) are highly conserved in aquaporin water channel family. Crystallographic studies of AQP1 structure demonstrated that the two NPA motifs are in the narrow central constriction of the channel, serving to bind water molecules for selective and effi-cient water passage. To investigate the importance of the two NPA motifs in the structure, function and biogenesis of aquaporin water channels, we generated AQP1 mutations with NPA1 deletion, NPA2 de-letion and NPA1,2 double deletion. The coding sequences of the three mutated cDNAs were subcloned into the mammalian expression vector pcDNA3.1 to form expression plasmids. We established stably transfected CHO cell lines expressing these AQP1 mutants. Immunofluorescence indicated that all the three mutated AQP1 proteins are expressed normally on the plasma membrane of stably transfected CHO cells, suggesting that deletion of NPA motifs does not influence the expression and intracellular processing of AQP1. Functional analysis demonstrated that NPA1 or NPA2 deletion reduced AQP1 water permeability by 49.6% and 46.7%, respectively, while NPA1,2 double deletion had little effect on AQP1 water permeability. These results provide evidence that NPA motifs are important for water per-meation but not essential for the expression, intracellular processing and the basic structure of AQP1 water channel.