猕猴属五个种mtDNA多态性研究

本文以10种限制性内切酶研究猕猴属5个种(Macaca mulatta.M.nemestrina.M.assemensis.M.thibetana,M arctoides)线粒体DNA进化。在13个个体中,共检出8种限制性类型。恒河猴种内存在广泛的线粒休DNA限制性片段长度多态性(RFLP)。结合日本猴(M.fuscata)的有关资料,构建了猕猴属6个种的分子系统树,并给出各个种的分化时间。结果表明,这6个种可分成4个类群,熊猴和藏酋猴、恒河猴和日本猴之间的遗传距离较近,可分别划为同一类群,红面猴与其他5种猴的遗传距离最远,在系统发生上分离最早。     

长江三角洲石荠苧属群体水平变异式样的研究

本文应用数量分类学方法对长江三角洲地区5种石荠苧属植物的群体进行了表征变异式样的分析,并参照繁育方式、生态适应和染色体数目等证据,来揭示种内群体间变异式样的差异及其与环境条件的关系,并探讨了这些种可能的种系发生关系。笔者认为石荠苧属Mosla在进化的早期就已经分化为两个大支,在分类上即表现为两个组——唇萼组和石荠苧组的分化。     

DA/DAPI-Fluorescent heteromorphism of human Y chromosome

Summary Variation of DA/DAPI intensity in the Yq12 band was observed in five amniotic cell specimens and one blood specimen from the father of one fetus. Three distinct classes of Yq heterochromatin were identified by distamycin A (DA) treatment of the cell cultures and various staining techniques. The heterochromatin in the Yq11.23 sub-band does not under-condense when exposed to DA, and shows pale fluorescence with quinacrine staining, positive C-banding, and bright fluorescence with DA/DAPI technique. This class of heterochromatin was consistently observed in all specimens studied. The other two classes of heterochromatin are in the Yq12 band. Both show undercondensation when exposed to DA, quinacrine-bright fluorescence, and positive C-banding; howover, one class of heterochromatin shows DA/DAPI-bright fluorescence and the other shows pale fluorescence. The size and banding intensity of the two classes of heterochromatin in Yq12 are variable. These results provide cytological evidence of heterogeneity within the Y heterochromatin region containing AT-rich DNA.     

Molecular characterization of ataxia telangiectasia T cell clones

Summary To delimit the 14q32.1 recurrent breakpoint of ataxia telangiectasia clones, we performed an in situ hybridization study with various probes located on the 14q32 band. We thus mapped this breakpoint between the D14S1 and Pi loci. Furthermore, an interstitial duplication including D14S1 and a part of the IgH locus was demonstrated on a t(14;14) clone.     

Interactions of porphyrins with purified DNA and more highly organized structures

Studies of the solution properties of gold(III)tetrakis(4-N-methylpyridyl) porphine and its DNA binding characteristics have been conducted utilizing uv/vis absorption spectroscopy, circular dichroism (CD), Mossbauer spectroscopy, and temperature-jump relaxation techniques. These studies indicate that over the concentration range considered this water soluble gold(III) porphyrin does not aggregate, binds axial ligands only weakly with a preference for soft Lewis bases, and is capable of intercalation into nucleic acids of appropriate base pair content. The interaction of this and several other porphyrins with the synthetic polynucleotide poly(dA-dC).poly(dT-dG) has been studied. Spectroscopic signatures for intercalation were found for those derivatives not having axial ligands. Intercalation into chromatin in vitro can also occur with those porphyrins and metalloporphyrins which do not have axial ligands. Finally, studies utilizing microinjection techniques indicate that once within the cell, tetrakis(4-N-methylpyridyl)porphine tends to localize in the nucleus.     

Complexity and tissue specificity of the mitochondrial respiratory chain

There is a renewed interest in the structure and functioning of the mitochondrial respiratory chain with the realization that a number of genetic disorders result from defects in mitochondrial electron transfer. These so-called mitochondrial myopathies include diseases of muscle, heart, and brain. The respiratory chain can be fractionated into four large multipeptide complexes, an NADH ubiquinone reductase (complex I), succinate ubiquinone reductase (complex II), ubiquinol oxidoreductase (complex III), and cytochromec oxidase (complex IV). Mitochondrial myopathies involving each of these complexes have been described. This review summarizes compositional and structural data on the respiratory chain proteins and describes the arrangement of these complexes in the mitochondrial inner membrane. This biochemical information is provided as a framework for the diagnosis and molecular characterization of mitochondrial diseases.     

Effects of traces of rare earth elements on the protozoanBlepherisma and on mice

The growth of the protozoanBlepherisma is stimulated by Lanthanum (La) at concentrations as low as 0.32 ppm. In mice Yttrium (Y) and Ytterbium (Yb) are absorbed, accumulated, and metabolized. Both rare earth elements (RE) exhibit a high affinity for teeth and bones, accumulation occurs and metabolism is slow. In the livers of RE-exposed mice, concentrations are variable. The liver is apparently capable of absorbing and discharging RE in a manner depending on metabolic activity. The main route of discharge for ingested REs is the alimentary canal. Exposure of pregnant mice to RE leads to rapid placental transfer of RE; 14.1% of the total amount of RE administered was detected in newborn mice. Young, developing organisms appear to be especially susceptible to RE accumulation.