棉纤维分化和发育研究进展

棉纤维分化和发育研究进展邱金龙王隆华颜季琼（华东师范大学生物系,上海２０００６２）ＡＤＶＡＮＣＥＳＩＮＴＨＥＳＴＵＤＹＯＮＤＩＦＦＥＲＥＮＴＩＡＴＩＯＮＡＮＤＤＥＶＥＬＯＰＭＥＮＴＯＦＣＯＴＴＯＮＦＩＢＥＲＱｉｕＪｉｎ－ｌｏｎｇＷａｎｇＬｏｎｇ－ｈ...     

白腹锦鸡和红腹锦鸡的遗传分化

白腹锦鸡Chrysolophus amherstiae (Leadbeater)和红腹锦鸡Chrysolophus pictus (L.)是两个种还是两个亚种尚有争议。测定了白腹锦鸡C.amherstiae两个个体部分细胞色素b基因序列,得到完全相同的861bp的序列。与红腹锦鸡C.pictus的同源序列相比,在21个位点上出现变异,应用木村资生的双参数法算出两者的遗传距离为2.5％。根据鸡形目细胞色素b基因核苷酸替换的速率约为每百万年0.5％～ 0.7％,推断出两种锦鸡的分化时间至少为1.7百万年。从而在分子水平上支持白腹锦鸡(C.amherstiae)和红腹锦鸡(C.pictus)是两个独立种。 Abstract：It was disputed that Chrysolophus amherstiae (Leadbeater) and Chrysolophus pictus (L.) were two species or two subspecies.DNA sequences spanning 861 nucleotide bases of the mitochondrial cytochrome-b gene were reported in two C.amherstiae.21 sites were different compared with C.pictus's homologous sequences. Genetic distance between C.amherstiae and was 2.5％ based on the Kimura's two parameter's methods.The divergence time between C.amherstiae and C.pictus was at least 1.7My based on the substitution rate of nucleotide acid of cytothrome-b gene in Galliformes.We suggested that Chrysolophus amherstiae and Chrysolophus pictus are two distinct species.     

两栖动物的性别决定和分化

性别发育是进化生物学领域备受关注的研究热点之一。性别发育主要包括性别决定和性别分化,脊椎动物的性别决定主要分为基因性别决定和环境性别决定两种模式。两栖动物的性别决定属于基因型性别决定模式,其基因型性别由受精时两性配子的性染色体决定,但性腺分化所产生的表型性别还会受环境温度和性激素的修饰。在两栖动物中性别逆转的现象普遍存在,其相关的生理和分子机制也有一定的研究。本文从性别相关基因对性别决定的影响、温度对两栖动物性别分化的影响、性激素对两栖动物性别分化的影响、温度和性激素对性别相关基因表达的影响等四方面对两栖动物性别决定和性别分化的生理和分子机制进行一定的概述,并提出了未来两栖动物性别发育研究的重点。     

线虫的性别分化和决定

线虫（Caeborhabditis elegans)是十分重要的模式生物。在遗传学,发育生物学以及神经生物学中有着广泛的应用。就线虫性别分化和性别决定相关基因的特性和功能进行了详细介绍,并在此基础上初步概括了其性别决定的分子机制。     

哈密瓜子叶分化和脱分化过程中RNaSe、DNase和IAAase活性的研究

RNase和DNase是参与核酸代谢的重要酶类之一,它们在植物体内既能降解RNA和DNA,又可以参与合成作用(Lehman,1976)。而IAAaes和过氧化物酶的活性对调节植物体内激素水平起主导作用,这在Galston工作中已有报道。在前人工作的基础上,本文在哈密瓜子叶诱导形成二种类型的愈伤组织过程中,对核酸代谢的两个重要酶类RNase和DNase以及在氧化还原过程中两个重要酶类IAAase和过氧化物酶进行了研究。     

油菜叶片及其脱分化和再分化中质体的电镜观察

我们用电镜观察了油菜叶片植株再生中质体的超微结构变化。在油菜叶肉细胞中,叶绿体的基粒,基质片层发育良好,偶尔有淀粉粒。在来自叶片的愈伤组织细胞中,质体体积变小,类囊体已经消失或部分消失,有的质体含有淀粉粒,但很少有质体小球。经培养分化后的愈伤组织,特别是在表层细胞中,质体数量急剧增多,形态变化很大,贮藏淀粉明显减少。基质内已有泡状或管状结构。有的质体已出现长的基质片层,但未见到基粒;质体中常有质体球。由此可见,质体是一个十分敏感的细胞器,它的变化与细胞分化有关,变化最大的部分是片层系统,贮藏淀粉,质体小球。片层系统中尤以基粒片层变化最为显著。     

一氧化氮和细胞——增殖、分化和死亡

《一氧化氮和细胞———增殖、分化和死亡》（ＮｉｔｒｉｃＯｘｉｄｅａｎｄｔｈｅＣｅｌｌ———Ｐｒｏｌｉｆｅｒａｔｉｏｎ，ＤｉｆｆｅｒｅｎｔｉａｔｉｏｎａｎｄＤｅａｔｈ）由Ｓ．Ｍｏｎｃａｄａ和Ｇ．Ｎｉｓｔｉｃò等编著，１９９８年ＰｏｒｔｌａｎｄＰｒｅｓｓ出版，３０５页。一氧化氮已经证明是一个具有广泛生物学意义的分子，具有从生理学到病理生理学范围内极大的作用。例如，细胞保护作用、细胞增殖、分化和死亡等。本书是有关一氧化氮研究的第二届国际Ｐａｒａｅｌｉｏｓ会议的讨论概况。一氧化氮和细胞——增殖、分化和…     

影响棉纤维分化和发育的因素

概述了棉纤维细胞分化和发育的过程,对影响棉纤雏分化和发育的因素进行了探讨,并对今后棉纤维的研究发展趋势进行了展望．     

人类T淋巴细胞的分化和功能

T细胞的分化从好几个种属的动物里已经证实,胸腺微环境在T细胞的分化和功能性成熟中的重要性。看来是骨髓前体细胞(前胸腺细胞)迁移至胸腺,经过加工变成功能性完全的细胞。然后输入到包括脾脏和淋巴结的周     

F.t.-i.r. and laser-Raman spectra of thymine and thymidine

F.t.-i.r. and laser-Raman spectra of thymine and thymidine in the solid state were recorded. Assignments were proposed for the frequencies observed. The influence of the deoxy sugar on the vibrations of the nucleoside are discussed as a function of its particular puckering. The aim of this work is to elucidate the differences between the molecules constituting the nucleic acids, in order the better to comprehend their biological functions.     

F.t.-i.r. and laser-Raman spectra of cytosine and cytidine

Fourier-transform infrared (F.t.-i.r.) and laser-Raman spectra of cytosine and cytidine in the solid state have been recorded and assignments of the frequencies made. Comparison of the observed frequencies for cytosine with those for cytidine permits identification of the bands characteristic of the sugar on the one hand, and of the pyrimidine base on the other.     

R.b.e. and o.e.r. of extended-Bragg-peak helium ions: survival and development of rat embryos.

Rats were exposed under aerobic or hypoxic conditions to 200-1200 rads of 60Co gamma-rays or extended-Bragg-peak helium ions on the eighth day of gestation. Uterine contents were examined on the twentieth day of gestation. At the 50 per cent embryonic survival level, helium ion r.b.e. was 1(.0) (aerobic) and 1(.2) (hypoxic). Maximum attainable gamma-ray and helium-ion o.e.r.s. were 2(.2) and 1(.7) respectively, indicating an oxygen-effect gain (o.e.g.) of 1(.2). At the 10 per cent survival level helium ion r.b.e. was 1(.1) (aerobic) and 1(.4) (hypoxic). Gamma-ray and helium-ion 0.e.r.s. were 2(.0) and 1(.5) respectively, indicating a helium ion o.e.g. of 1(.3). These data demonstrate that the small fraction of high-LET radiation present in this helium ion beam has a neglible effect on the aerobic r.b.e., but lowers the effective o.e.r. of the beam approximately 25 per cent relative to that of gamma-rays. Helium ions were significantly more effective than gamma-rays in killing embryos under hypoxic conditions, in producing congenital abnormalities under aerobic conditions, and in stunting foetal growth under both conditions.     

F.t.-i.r. and laser-Raman spectra of guanine and guanosine

Fourier-transform infrared (F.t.-i.r.) and laser-Raman spectra have been obtained for solid guanine. The F.t.-i.r. spectrum of guanosine in the solid state was also recorded. Assignments are proposed for the i.r. bands. The molecular basis of the spectral differences between guanine and guanosine are discussed.