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41.
从手术切除的24例女性和12例男性尖锐湿疣新鲜标本中,以及42例女性尖锐湿疣、16例男性外耳道乳头状瘤和4例女性假性湿疣的石蜡包埋标本中,提取组织的基因组DNA,用人工合成的人乳头瘤病毒6.11和16型E6区特异性寡聚核苷酸引物,通过PCR进行HPV DNA的分型检测。结果66例女性尖锐湿疣中,感染HPV6型者4例,感染11型者12例,6+11型混合感染者49例;阴性1例,总检出率达98.4%。4例女性假性湿疣中1例为HPV6型感染,阳性率25%。16例男性外耳道乳头状瘤中HPV6+11型感染者5例,6+16型感染者3例,6+11+16型多重感染者8例,阳性率100%。12例男性尖锐湿疣中,HPV11型感染者7例,6+11型4例,阴性1例,总阳性率91.6%。还对细胞学上空泡化和非典型空泡化尖锐湿疣标本的HPV感染做了比较,未发现差异。 相似文献
42.
为保护广西北部湾海岸带、海岛的植物多样性和生态系统多样性,通过样方、样带法野外实地调查并结合文献资料,对其外来入侵植物的物种组成、原产地、生活型、入侵途径和危害状况等进行了分析。结果表明,广西北部湾海岸带、海岛共有入侵植物64种,隶属28科55属,其中菊科(Asteraceae)最多(15种)。草本植物最多,有48种(75.00%)。原产地来自美洲的植物最多,有49种。入侵风险等级可划分为5个等级,其中Ⅰ级严重危害的有8种(12.50%)。与广西、广东、海南及华南地区的外来入侵植物在物种组成、生活型和原产地等方面呈现出较强的相似性;北部湾与广西中越边境内陆地区来自美洲的入侵植物都超过60%。因此推测广西外来入侵植物有两条可能的入侵线路:一是从海南登录,二是从中越边境跨入。广西北部湾海岸带、海岛的外来入侵植物总数(相对整个广西)虽较少,但其8种Ⅰ级严重危害植物的防治,仍需引起重视。 相似文献
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44.
Jing‐Fang Guo Baosheng Wang Zhan‐Lin Liu Jian‐Feng Mao Xiao‐Ru Wang Wei Zhao 《植物分类学报:英文版》2023,61(1):143-156
Endemic species are important components of regional biodiversity and hold the key to understanding local adaptation and evolutionary processes that shape species distributions. This study investigated the biogeographic history of a relict conifer Pinus bungeana Zucc. ex Endl. confined to central China. We examined genetic diversity in P. bungeana using genotyping-by-sequencing and chloroplast and mitochondrial DNA markers. We performed spatial and temporal inference of recent genetic and demographic changes, and dissected the impacts of geography and environmental gradients on population differentiation. We then projected P. bungeana's risk of decline under future climates. We found extremely low nucleotide diversity (average π 0.0014), and strong population structure (global FST 0.234) even at regional scales, reflecting long-term isolation in small populations. The species experienced severe bottlenecks in the early Pliocene and continued to decline in the Pleistocene in the western distribution, whereas the east expanded recently. Local adaptation played a small (8%) but significant role in population diversity. Low genetic diversity in fragmented populations makes the species highly vulnerable to climate change, particularly in marginal and relict populations. We suggest that conservation efforts should focus on enhancing gene pool and population growth through assisted migration within each genetic cluster to reduce the risk of further genetic drift and extinction. 相似文献
45.
六种鼠苹果酸脱氢酶,血浆蛋白质和血红蛋白的变异分析 总被引:3,自引:0,他引:3
本文分析了家鼠属(Rattus)4种鼠和姬鼠属(Apodemus)2种鼠的苹果酸脱氢酶、血浆中β1区和β2区蛋白质、血浆清蛋白、前清蛋白以及红细胞中血红蛋白的变异。结果表明,MDH在进化上是比较保守的,其中MDHm和MDHs2带在各鼠间位于同一泳动线上,仅MDHs1带的泳动速度出现属间和种间的微小差异;血浆中β1区和β2区的蛋白质带、清蛋白带以及前清蛋白带各鼠间出现明显的变异,表现为黑线姬鼠和社鼠在β1区出现2种多态型区带,褐家鼠在β2区也有2种多态型带;各鼠间的血红蛋白变异比较明显,主要表现在区带数和主成分的泳动度显著不同,而且社鼠的Hb出现3种多态型,黄毛鼠出现2种多态型,其余各鼠的Hb皆为单态性。上述16项生化特性按相似和相异进行配对比较,初步表明黄毛鼠与褐家鼠亲缘上比较相近,白腹巨鼠要比其他3种鼠亲缘上更接近于黑线姬鼠,而社鼠与白腹巨鼠之间进化分歧相对地较大。 相似文献
46.
Nicolas Bouquin Mao X. Chen Sunghoon Kim Françoise Vannier Sylvie Bernard I. Barry Holland Simone J. Séror 《Molecular microbiology》1996,20(4):853-865
We previously described a mutation feeB1 conferring a temperature-sensitive filamentation phenotype and resistance to the calmodulin inhibitor 48/80 in Escherichia coli, which constitutes a single base change in the acceptor stem of the rare tRNA3Leu recognizing CUA codons. We now describe a second mutant, feeA1, unlinked to feeB, but displaying a similar phenotype, 48/80 resistance and a reduced growth rate at the permissive temperature, 30°C, and temperature-sensitive, forming short filaments at 42°C. In the feeA mutant, tRNA3Leu expression (but not that of tRNA1Leu) was reduced approximately fivefold relative to the wild type. We previously showed that the synthesis of β-galactosidase, which unusually requires the translation of 6-CUA codons, was substantially reduced, particularly at 42°C, in feeB mutants. The feeA mutant also shows drastically reduced synthesis of β-galactosidase at the non-permissive temperature and reduced levels even at the permissive temperature. We also show that increased copy numbers of the abundant tRNA1Leu, which can also read CUA codons at low efficiency, suppressed the effects of feeA1 under some conditions, providing further evidence that the mutant was deficient in CUA translation. This, and the previous study, demonstrates that mutations which either reduce the activity of tRNA3Leu or the cellular amount of tRNA3Leu confer resistance to the drug 48/80, with concomitant inhibition of cell division at 42°C. 相似文献
47.
48.
Yeast mRNA cap methyltransferase is a 50-kilodalton protein encoded by an essential gene. 总被引:9,自引:1,他引:8
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RNA (guanine-7-)methyltransferase, the enzyme responsible for methylating the 5' cap structure of eukaryotic mRNA, was isolated from extracts of Saccharomyces cerevisiae. The yeast enzyme catalyzed methyl group transfer from S-adenosyl-L-methionine to the guanosine base of capped, unmethylated poly(A). Cap methylation was stimulated by low concentrations of salt and was inhibited by S-adenosyl-L-homocysteine, a presumptive product of the reaction, but not by S-adenosyl-D-homocysteine. The methyltransferase sedimented in a glycerol gradient as a single discrete component of 3.2S. A likely candidate for the gene encoding yeast cap methyltransferase was singled out on phylogenetic grounds. The ABD1 gene, located on yeast chromosome II, encodes a 436-amino-acid (50-kDa) polypeptide that displays regional similarity to the catalytic domain of the vaccinia virus cap methyltransferase. That the ABD1 gene product is indeed RNA (guanine-7-)methyltransferase was established by expressing the ABD1 protein in bacteria, purifying the protein to homogeneity, and characterizing the cap methyltransferase activity intrinsic to recombinant ABD1. The physical and biochemical properties of recombinant ABD1 methyltransferase were indistinguishable from those of the cap methyltransferase isolated and partially purified from whole-cell yeast extracts. Our finding that the ABD1 gene is required for yeast growth provides the first genetic evidence that a cap methyltransferase (and, by inference, the cap methyl group) plays an essential role in cellular function in vivo. 相似文献
49.
The level of aggressiveness and the weight of preputial gland and testis in male mice (Mus musculus) were influenced by housing condition, especially by the presence of cohabitant males. In this study, the relation between
aggressiveness and the preputial gland and testis weight was studied for various housing conditions. The mouse individually
housed in a cage that was linked to another cage containing another male separated by wire net was more aggressive than isolated
or paired mice. The preputial gland weight also showed the same tendency, suggesting that the odor from other males promotes
pituitary-gonadal activity in males, and that long-term cohabitance inhibits it. 相似文献
50.
短盖巨脂鲤卵巢发育组织学研究 总被引:3,自引:0,他引:3
通过对短盖巨脂鲤各个生长时期卵巢组织学研究以及成熟卵超微结构观察,获得短盖巨脂鲤生长发育过程中卵巢发育规律;同时对卵母细胞核仁排出物与核质关系及在卵黄形成中的作用等问题作了初步探讨;并根据卵巢的卵母细胞组成确定了其产卵类型。 相似文献