低温敏感不育水稻育性敏感期细胞色素氧化酶活性

以常规品种特青作对照，分别测定了特青、低温敏感核不育材料Ｎ１０Ｓ、Ｎ１３Ｓ，在花粉母细胞形成期和花粉母细胞减数分裂期不同育性条件下的叶片和幼穗花药的细胞色素氧化酶的活性，并进行了统计学分析———两因素方差分析（Ｆ检验）及平均数的Ｄｕｎｃａｎ多重比较．结果表明，在育性敏感的２个时期，Ｎ１０Ｓ和Ｎ１３Ｓ不育株幼穗花药的细胞色素氧化酶的活性极显著低于可育株细胞色素氧化酶的活性，Ｎ１０Ｓ在育性敏感的２个时期分别为７２．０％和６３．２％，Ｎ１３Ｓ则分别为７２．１％和６７．７％．这就使得不育株花药中能量供应短缺，造成物质合成等许多生命活动衰减，最终导致不育     

Mitochondrial cytochrome b sequences variation of Protura and molecular systematics of Apterygota

Mitochondrial cytochrome b genes of about 450 bp fragments from 3 proturan species, 5 collembolan species and 2 dipluran species have been sequenced. The number of nucleotide substitutions and Kimura 2-parameter distances have also been calculated, and a series of molecular phylogenetic trees reconstructed by using parsimony and distance methods. The proturan, collembolan and dipluran species have evolved monophyletic groups. The results suggest that Protura and Collembola are sister groups, while Diplura is more or less demonstrating a closer phylogenetic relationship to the pterygotan insects. The phylogeny and their systematic position of protura and other groups are also discussed.     

羚牛细胞色素b基因序列分析和系统进化研究

应用聚合酶链式反应（PCR）分别扩增了羚牛、绵羊、山羊、黄牛细胞色素b基因,并对其全序列（1140bp）进行了测定。其中羚牛细胞色素b基因序列属首次报道。通过对8种偶蹄类动物细胞色素b基因序列差异分析和基于序列差异所构建的分子系统树,发现羚牛与羊亚科的动物亲缘关系最近,与其他动物亲缘关系较远。表明将羚牛放入羊亚科较为合理,序列差异分析还表明羚羊约在距今500万年前（上新世）从牛类动物中分化出来,牛类分化时间约在600万年前的中新世（Miocene）。     

Identification of inhibitor of apoptosis specific DNase in Xenopus egg extract

When added with cytochrome c, Xenopus laevis egg extract XS-150 can induce exogenous nuclei undergoing apoptosis. Apoptosis specific DNase XAD was activated during this process, and cut chromatin between nucleosome, leading to DNA Ladder in electrophoresis. Our results showed that an inhibitor of XAD, IXAD, exists abundantly in normal egg extract, its molecular weight is about 40 ku. Normally, IXAD exists either in the form of dimmer or in complex with XAD. It was degraded during apoptosis, releasing active XAD. The results of Western assay and cross-inhibition showed that IXAD was likely homologous to DFF45 in structure and function. At the same time, these results also indicated that the pathway in apoptosis was conserved in evolution.     

我国不同地区二尾蛱蝶线粒体细胞色素氧化酶Ⅱ的DNA序列差异

通过对我国不同地区二尾蛱蝶线粒体细胞色素氧化酶Ⅱ（COⅡ）DNA部分序列的比较分析,研究了二尾蛱蝶的遗传分化以及台湾海峡对其分化的影响。台湾和大陆二尾蛱蝶的COⅡ基因有0.75%～1%的差异,估算其分化时间大约在37.5～50万年前,台湾海峡可能有效地阻隔了两岸二尾蛱蝶的基因交流;台湾和大陆二尾蛱蝶间明显的基因差异可能与它们分属不同亚种有关,而大陆上不同地区的二尾蛱蝶也有较大的基因差异,推测大陆二尾蛱蝶可能存在2个亚种。     

细胞色素P450与农药相互作用及其机理研究

综述了细胞色素P450的种类和功能多样性,介绍了细胞色素P450参与除草剂代谢及其作用机理．同时,简述了细胞色素P450 14DM与杀菌剂特异性作用的机制．报道了我们从抗除草剂的瑞士黑麦草中克隆CYP8181同源基因及其功能的研究,以及柑橘绿霉菌细胞色素P450 14DM基因的克隆表达．为深入研究杀菌剂作用细胞色素P450 14DM的机理从而设计以P450 14DM为特异性靶标的新型农药、以及进一步研究细胞色素P450酶系与除草剂代谢的关系打下了良好的基础．     

Estimated evolutionary tempo of East Asian gobionid fishes (Teleostei: Cyprinidae) from mitochondrial DNA sequence data

The rapid development of molecular phylogenetic analysis has provided a new path to investigate the tempo of evolution.In this work,a rather complete molecular phylogeny of the East Asian gobionid fishes was constructed based on mtDNA cytochrome b gene sequences.Molecular clock analysis was then applied to investigate the speciation tempo of this group.The phylogenetic analysis revealed four major groups that were in agreement with previous studies.Lineage numbers plotted over time indicate that gobionid li...     

Cytochrome c release and endoplasmic reticulum stress are involved in caspase-dependent apoptosis induced by G418

G418 is used extensively in transfection experiments to select eukaryotic cells that have acquired neomycin resistance genes, but the mechanism is still elusive. To investigate this, we treated normal rat kidney cells with G418 for 3 days and found that the cells presented typical apoptotic features such as cell shrinkage, nuclear fragmentation, and caspase-3 activation. However, there was no low-molecular DNA ladder. The pan caspase inhibitor z-VAD-fmk completely inhibited this type of apoptosis, suggesting a caspase-dependent mechanism. Caspase cascades in apoptosis induced by G418 were initiated by at least two pathways: the release of cytochrome c from mitochondria, which was observed under confocal microscopy, and endoplasmic reticulum stress, demonstrated by the increase in Ca²⁺ concentration and the cleavage of m-calpain and procaspase-12. Both pathways activated caspase-9. Inhibition of caspase-9 activity by z-LEHD-fmk prevented most of the cells from apoptosis, and E-64d, an inhibitor of calpain accentuated this block. The cleavage of casapse-9 and caspase-12 was blocked only by simultaneous application of z-VAD-fmk and E-64d, but not by either alone. E-64d did not prevent the release of cytochrome c. These results indicated that these two pathways were independent of each other. Received 1 April 2004; received after revision 21 April 2004; accepted 26 May 2004