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91.
Zhi-Hui Su Osamu Tominaga Takeshi Ohama Eiji Kajiwara Ryoshuke Ishikawa Tokindo S. Okada Keiko Nakamura Syozo Osawa 《Journal of molecular evolution》1996,43(6):662-671
Molecular phylogenetic analyses using mitochondrial NADH dehydrogenase subunit 5 (ND5) gene sequences representing all 15 species and the majority of subspecies or races of theOhomopterus ground beetles from all over the Japanese archipelago have uncovered a remarkable evolutionary history. Clustering of the species in the molecular phylogenetic tree is linked to their geographic distribution and does not correlate with morphological characters. Taxonomically the same species or the members belonging to the same species-group fall out in more than two different places on the ND5 tree. Evidence has been presented against a possible participation of ancestral polymorphism and random lineage sorting or of hybrid individuals for the observed distribution of mitochondrial DNA haplotypes. The most plausible explanation of our results is that parallel evolution took place in different lineages. Most notably,O. dehaanii, O. yaconinus, andO. japonicus in a lineage reveal almost identical morphology with those of the same species (or subspecies) but belonging to the phylogenetically remote lineages.The nucleotide sequence data reported in this paper will appear in the DDBJ, EMBL, and GenBank nucleotide sequence databases with accession numbers D50711-DD-50733 and D87131-D87186. 相似文献
92.
Role of viral antigens in destructive cellular immune responses to adenovirus vector-transduced cells in mouse lungs. 总被引:8,自引:3,他引:5 下载免费PDF全文
Adenoviruses missing E1 have been used as gene delivery vectors to the lungs for the treatment of cystic fibrosis. Transient expression of the recombinant gene and the development of inflammation have been two major limitations to the application of first-generation recombinant adenoviruses for gene therapy. Studies with mouse models of liver- and lung-directed gene therapy suggested that CD8+ cytotoxic T lymphocytes (CTLs) are effectors that contribute to extinction of transgene expression. The precise antigens responsible for activation of CTLs have not been identified. In this study, we examine the relative contributions of viral proteins versus the transgene product to the activation of CTLs which eliminate transgene-containing cells in mouse lungs. Instillation of a lacZ-expressing virus into the lungs of C57BL/6 mice elicited CTL responses to both viral proteins and the transgene product, beta-galactosidase, which collectively contribute to loss of trans-gene expression in mouse airways. Similar results were obtained in two experimental models in which the animals should be tolerant to the transgene, i.e., lacZ virus delivered to an animal transgenic for lacZ and a virus expressing the liver-specific enzyme ornithine transcarbamylase administered to the lungs of various strains of immune-competent mice. These data confirm the hypothesis that CTLs specific for viral antigens contribute to the problem of transgene instability in mouse lungs and indicate that CTLs specific for transgene product alone cannot account for the observed problem. 相似文献
93.
DNA Segments Sensitive to Single-Strand-Specific Nucleases Are Present in Chromatin of Mitotic Cells
It was observed before that DNAin situin chromatin of mitotic cells is more sensitive to denaturation than DNA in chromatin of interphase cells. DNA sensitivity to denaturation, in these studies, was analyzed by exposing cells to heat or acid and using acridine orange (AO), the metachromatic fluorochrome which can differentially stain double-stranded (ds) vs single-stranded (ss) nucleic acids, as a marker of the degree of DNA denaturation. However, without prior cell treatment with heat or acid no presence of single-stranded DNA in either mitotic or interphase cells was detected by this assay. In the present experiments we demonstrate that DNAin situin mitotic cells, without any prior treatment that can induce DNA denaturation, is sensitive to ss-specific S1 and mung bean nucleases. Incubation of permeabilized human T cell leukemic MOLT-4, promyelocytic HL-60, histiomonocytic lymphoma U937 cells, or normal PHA-stimulated lymphocytes with S1 or mung bean nucleases generated extensive DNA breakage in mitotic cells. DNA strand breaks were detected using fluorochrome-labeled triphosphonucleotides in the reaction catalyzed by exogenous terminal deoxynucleotidyl transferase. Under identical conditions of the cells’ exposure to ss-specific nucleases, DNA breakage in interphase cells was of an order of magnitude less extensive compared to mitotic cells. The data indicate that segments of DNA in mitotic chromosomes, in contrast to interphase cells, may be in a conformation which is sensitive to ss nucleases. This may be a reflection of the differences in the torsional stress of DNA loops between interphase and mitotic chromatin. Namely, greater stress in mitotic loops may lead to formation of the hairpin-loop structures by inverted repeats; such structures are sensitive to ss nucleases. The present method of detection of such segments appears to be more sensitive than the use of AO. The identification of mitotic cells based on sensitivity of their DNA to ss nucleases provides an additional method for their quantification by flow cytometry. 相似文献
94.
Maria de Fatima Bonaldo Pierre Jelenc Long Su Lee Lawton M. -T. Wu Dorothy Warburton Marcelo Bento Soares 《Human genetics》1996,97(4):441-452
A study was conducted on the feasibility of isolating genes and pseudogenes that map to chromosome 13 by a hybridization-based approach using a 13-specific library and pools of repeat-free cDNA clones. Five pairs of cDNA and chromosome 13 genomic clones were identified and characterized. Partial or full-length sequence was derived from all cDNAs, and database searches were performed for putative gene identification. Partial sequence was also obtained from the chromosome 13 genomic clones for comparison with those of the hybridizing cDNAs. As a result of these analyses we identified three genes, a putative homologue of a porcine mRNA encoding an unidentified hepatic protein, a putative homologue of a yeast integral membrane protein, and a gene for a translationally controlled tumor protein, and two processed pseudogenes, ribosomal proteins L23a and S3a. The latter was formerly identified as the v-fos transformation effector gene, Fte-1, and recently cited as a possible candidate for the BRCA2 gene on chromosome 13. All genes and pseudogenes were localized to cytogenetic bands by in situ hybridization of metaphase chromosomes with probes derived from the chromosome 13 genomic clones. 相似文献
95.
以异源四倍体体细胞杂种为父本杂交培育三倍体柑桔植株的研究 总被引:23,自引:1,他引:22
以 3个柑桔原生质体融合而来的四倍体体细胞杂种为父本 ,与二倍体单胚性种柚子 (Citrusgrandis)以及单多胚混合型品种“华农本地早”桔 (C.reticulata)有性杂交 ,授粉后 90 d,发现种子干瘪 ,大部分种子的胚败育。将干瘪种子在 MT附加 1mg/L GA3 或 50 0 mg/L麦芽浸出物的培养基中 ,经培养抢救 ,有 2 5.6%的种子萌发成苗或继续进行胚的生长 ,后者进一步诱导能形成丛芽 ,经试管嫁接或诱导生根形成完整植株。共获得 6个组合 73棵完整植株 ,染色体数检查表明 ,2 0株为三倍体 (2 n=3x=2 7) ,32株为二倍体 (2 n=2 x=18) ,8株为非整倍体 ,其它 13株还有待于进一步检查。 相似文献
96.
菜用大豆产量相关性状的遗传分析 总被引:7,自引:0,他引:7
对 19个菜用大豆品种与产量有关的10个农艺性状进行遗传分析的结果表明,生育期和主茎节数遗传力偏高;单株荚数、分枝数遗传力偏低;单株产量、单株荚数的遗传变异系数很大,其遗传进度的值也较大;生育期的遗传变异系数小, 遗传进度也小,遗传相关分析结果表明,产量与生育期、单株结荚数相关关系密切。菜用大豆遗传参数分析结果与前人对食用大豆的研究结果趋势一致。 相似文献
97.
懒猴属的核糖体DNA变异及其种间分化关系 总被引:5,自引:2,他引:3
用15种限制性内切酶和人28S、18SrDNA探针构建了懒猴属各物种核糖体DNA重复单位的限制性内切酶图谱。在进化速率较高的非转录间隔区,在大、中、小懒猴中分别定位了23、24、24个酶切位点。大懒猴与中懒猴有12个位点不同,与小懒猴有14个位点不同,而中、小懒猴间则只有一个位点的差异。经过计算,大懒猴与中懒猴的遗传距离值为12.65%,与小懒猴的差异为14.24%,中、小懒猴间的差异则仅为0.7 相似文献
98.
云南姬鼠的蛋白多态性及其遗传分化关系 总被引:3,自引:0,他引:3
本文采用蛋白电泳技术对来源于云南省若干地区的姬鼠属(Apodemus)的3种姬鼠──高山姬鼠(A.chevrieri)8只,中华姬鼠(A.draco)3只和大耳姬鼠(A.latronum)1只,以及作为外群的同科的绒鼠属的大绒鼠(Hapalomysdelalori)3只进行了分析。共检测遗传座位27个,发现21个座位存在多态性。根据蛋白多态的数据对研究对象进行遗传分化关系的探讨,用系统分析软件PHYLIP计算它们之间的分化关系,得到了一棵无根系统树。结果表明,作为外群的大绒鼠明显不同于其它3种姬鼠而聚在最外面。8只高山姬鼠个体汇聚成独立的一支,中华姬鼠的3个个体也聚成一支,但大耳姬鼠却聚在中华姬鼠一支中,因此我们认为大耳姬鼠同中华姬鼠的分化时间可能比较晚近。 相似文献
99.
100.