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1.
空间条件对几种粮食作物的同工酶和细胞学特性的影响   总被引:47,自引:0,他引:47  
搭载1987年发射的两颗返地卫星(8月5—10日和9月9—17日)的几种小麦、大麦种子,经回收后初步研究表明:(1)对发芽率的影响:空间处理的种子,其发芽率与对照无差别;(2)对茎及生育期的影响:空间处理的种子长成的幼苗比对照强壮,植株高度有些品种明显的矮于对照。生育期有不同程度延长;(3)对染色体结构的影响:花粉母细胞减数分裂观察表明搭载卫星的种子当代可诱导出比地面更多的染色体桥、落后染色体及染色体数目异于正常体细胞数目的现象。小麦品种Cocorit—71经空间处理后花粉母细胞的染色体数目异常可高达20.51%,而地面对照组其花粉母细胞基本正常(2n=28);(4)对同工酶的影响:经空间处理的小麦种子酯酶、过氧化物酶的同工酶谱带空间处理的比地面对照减少。由此可见,空间处理可诱导纯合植物种子发生变异,为农作物育种创造一个新途径。  相似文献   
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Pygoscelis penguins are experiencing general population declines in their northernmost range whereas there are reported increases in their southernmost range. These changes are coincident with decadal‐scale trends in remote sensed observations of sea ice concentrations (SIC) and sea surface temperatures (SST) during the chick‐rearing season (austral summer). Using SIC, SST, and bathymetry, we identified separate chick‐rearing niche spaces for the three Pygoscelis penguin species and used a maximum entropy approach (MaxEnt) to spatially and temporally model suitable chick‐rearing habitats in the Southern Ocean. For all Pygoscelis penguin species, the MaxEnt models predict significant changes in the locations of suitable chick‐rearing habitats over the period of 1982–2010. In general, chick‐rearing habitat suitability at specific colony locations agreed with the corresponding increases or decreases in documented population trends over the same time period. These changes were the most pronounced along the West Antarctic Peninsula where there has been a rapid warming event during at least the last 50 years.  相似文献   
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We identified Xenopus pericentriolar material-1 (PCM-1), which had been reported to constitute pericentriolar material, cloned its cDNA, and generated a specific pAb against this molecule. Immunolabeling revealed that PCM-1 was not a pericentriolar material protein, but a specific component of centriolar satellites, morphologically characterized as electron-dense granules, approximately 70-100 nm in diameter, scattered around centrosomes. Using a GFP fusion protein with PCM-1, we found that PCM-1-containing centriolar satellites moved along microtubules toward their minus ends, i.e., toward centrosomes, in live cells, as well as in vitro reconstituted asters. These findings defined centriolar satellites at the molecular level, and explained their pericentriolar localization. Next, to understand the relationship between centriolar satellites and centriolar replication, we examined the expression and subcellular localization of PCM-1 in ciliated epithelial cells during ciliogenesis. When ciliogenesis was induced in mouse nasal respiratory epithelial cells, PCM-1 immunofluorescence was markedly elevated at the apical cytoplasm. At the electron microscopic level, anti-PCM-1 pAb exclusively labeled fibrous granules, but not deuterosomes, both of which have been suggested to play central roles in centriolar replication in ciliogenesis. These findings suggested that centriolar satellites and fibrous granules are identical novel nonmembranous organelles containing PCM-1, which may play some important role(s) in centriolar replication.  相似文献   
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The stick insect Clonopsis gallica is a morphologically stable obligate parthenogen, ranging from North Africa to southern Europe, with a variable karyotype (54–57 chromosomes), considered diploid or triploid. Clonopsis gallica origin and relationships with Clonopsis algerica and Clonopsis maroccana remained unknown. Our Moroccan samples shared the same egg and body patterns and, in addition to C. gallica (2 n  = 54, XX), comprised the new bisexual Clonopsis sp. 1 (2 n  = 35/36, X0/XX) and the new all-female Clonopsis sp. 2 (2 n  = 72, XX), apparently forming a numerically polyploid series with re-diplodized karyotypes; C. gallica could thus be a triploid hybrid in origin. Furthermore, two strains of ameiotic males with 2 n  = 35 (X0) or 53 (X0) were found, which would maintain themselves as clonal androgens. We could conclude that in stick insects body and karyotype 'phenotypes' are considerably independent, thus preventing a sound taxonomy. Generally, the high heterozygosity of hybrids allows parthenogens to persist for long, particularly when hybrid polyploids are produced, as backcrosses of the hybrids to the parental species allow repeated incorporations of genetically diversified genomes. The distribution range of Clonopsis parthenogens appears to realize a sound instance of geographical parthenogenesis.  相似文献   
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The diploid chromosome number of two specimens of Lepilemur mustelinus (I. Geoffroy 1851) is 2N = 20. All of the chromosomes, except the Y chromosome, are metacentric or submetacentric; the Y chromosome is acrocentric and is the shortest chromosome in the complement. Satellites on autosomal pair 5 provide marked chromosomes for the animals studied and may be a marked pair for the species.  相似文献   
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Justin Joachim 《Autophagy》2017,13(12):2113-2114
Yeast have one Atg8 protein; however, multiple Atg8 orthologs (LC3s and GABARAPs) are found in humans. We discovered that a population of the Atg8 ortholog GABARAP resides on the centrosome and the peri-centrosomal region. This centrosomal pool of GABARAP translocates to forming autophagosomes upon starvation to activate autophagosome formation in a non-hierarchical pathway. How this centrosome-to-phagophore delivery of GABARAP occurs was not understood. To address this, we have shown that the archetypal centriolar satellite protein PCM1 regulates recruitment of GABARAP to the centrosome. PCM1 recruits GABARAP, but not MAP1LC3B, directly to centriolar satellites through a LC3-interacting region (LIR) motif. Furthermore, PCM1, in concert with its interacting centriolar satellite E3 ligase MIB1, controls GABARAP stability, K48-linked ubiquitination and GABARAP-mediated autophagic flux.  相似文献   
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短额负蝗与中华蚱蜢精子比较(直翅目:蝗总科)奚耕思,郑哲民(陕西师范大学动物研究所陕西省西安市710062)短额负蝗Atractomorphasinensis与中华蚱蜢Acridacinerea为中国两种常见的蝗虫。由于头顶细纵沟,后足股节外侧花纹及...  相似文献   
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本文通过对日本黄脊蝗Patangajapoinca(I.Bd),短角直斑腿蝗StenocatantopsmistshenkoiWill和霍山蹦蝗SinopodismahoushanaHuang精子的比较,发现了它们的精子的线粒体衍生体和中心粒侧体的超微形态结构十分相似,在精子发生过程中7、8两期精细胞线粒体衍生体周围微管的排数相一致,这3个种精子间的差异主要反映在外形头和尾的长度,线粒体衍生体的大  相似文献   
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