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Evidence for naturally occurring murine sarcoma virus 总被引:4,自引:0,他引:4
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Direct evidence for extensive paternal mitochondrial DNA inheritance in the marine mussel Mytilus. 总被引:17,自引:0,他引:17
Inheritance of mitochondrial DNA in animals was thought to be strictly maternal. Recently, evidence for incidental paternal mtDNA leakage was obtained in hybrid crosses of Drosophila and mice. In mice, the frequency of paternal mtDNA contributions was estimated at 10(-4), compared with maternal contributions. The common occurrence in the marine mussel Mytilus of heteroplasmic individuals with two or more types of highly diverged mtDNA molecules was interpreted as strong evidence for biparental mtDNA inheritance by some, but not by others. We report here results from pair-matings involving two species of mussels, Mytilus edulis and Mytilus trossulus. Extensive contribution of paternal mtDNA, amounting to several orders of magnitude higher than that inferred for Drosophila or mice, was observed in both intra- and interspecific crosses. 相似文献
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P. Baumann A. N. Tchernitchin G. Grunert P. Ball 《Cellular and molecular life sciences : CMLS》1986,42(2):165-167
Summary This paper describes the induction of uterine eosinophilia as well as of deep endometrial edema and increase of uterine wet weight in the immature rat by the catecholestrogens 2-OH-estradiol and 4-OH-estradiol. These effects are thought to be mediated by eosinophils via a specific eosinophil receptor system. 4-OH-estradiol was equipotent with estradiol, whereas the effect of 2-OH-estradiol was significantly weaker.Acknowledgments. This work was supported by Grant B-1493-8435 from the University of Chile. We are indebted to Prof. R. Knuppen, Lübeck, for providing the CE. 相似文献
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Summary A second (challenge) infection ofEimeria nieschulzi in clinically immune rats did not produce weight gain depression but caused a decrease in the absorption of glycine from the ileum. The malabsorption due to challenge was equivalent to that caused by the primary infection which did cause weight loss. 相似文献
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Conservation of the sequence and temporal expression of let-7 heterochronic regulatory RNA 总被引:72,自引:0,他引:72
Pasquinelli AE Reinhart BJ Slack F Martindale MQ Kuroda MI Maller B Hayward DC Ball EE Degnan B Müller P Spring J Srinivasan A Fishman M Finnerty J Corbo J Levine M Leahy P Davidson E Ruvkun G 《Nature》2000,408(6808):86-89
Two small RNAs regulate the timing of Caenorhabditis elegans development. Transition from the first to the second larval stage fates requires the 22-nucleotide lin-4 RNA, and transition from late larval to adult cell fates requires the 21-nucleotide let-7 RNA. The lin-4 and let-7 RNA genes are not homologous to each other, but are each complementary to sequences in the 3' untranslated regions of a set of protein-coding target genes that are normally negatively regulated by the RNAs. Here we have detected let-7 RNAs of approximately 21 nucleotides in samples from a wide range of animal species, including vertebrate, ascidian, hemichordate, mollusc, annelid and arthropod, but not in RNAs from several cnidarian and poriferan species, Saccharomyces cerevisiae, Escherichia coli or Arabidopsis. We did not detect lin-4 RNA in these species. We found that let-7 temporal regulation is also conserved: let-7 RNA expression is first detected at late larval stages in C. elegans and Drosophila, at 48 hours after fertilization in zebrafish, and in adult stages of annelids and molluscs. The let-7 regulatory RNA may control late temporal transitions during development across animal phylogeny. 相似文献
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