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231.
The influenza A viral heterotrimeric polymerase complex (PA, PB1, PB2) is known to be involved in many aspects of viral replication and to interact with host factors, thereby having a role in host specificity. The polymerase protein sequences from the 1918 human influenza virus differ from avian consensus sequences at only a small number of amino acids, consistent with the hypothesis that they were derived from an avian source shortly before the pandemic. However, when compared to avian sequences, the nucleotide sequences of the 1918 polymerase genes have more synonymous differences than expected, suggesting evolutionary distance from known avian strains. Here we present sequence and phylogenetic analyses of the complete genome of the 1918 influenza virus, and propose that the 1918 virus was not a reassortant virus (like those of the 1957 and 1968 pandemics), but more likely an entirely avian-like virus that adapted to humans. These data support prior phylogenetic studies suggesting that the 1918 virus was derived from an avian source. A total of ten amino acid changes in the polymerase proteins consistently differentiate the 1918 and subsequent human influenza virus sequences from avian virus sequences. Notably, a number of the same changes have been found in recently circulating, highly pathogenic H5N1 viruses that have caused illness and death in humans and are feared to be the precursors of a new influenza pandemic. The sequence changes identified here may be important in the adaptation of influenza viruses to humans. 相似文献
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Genome sequencing and analysis of Aspergillus oryzae 总被引:4,自引:0,他引:4
Machida M Asai K Sano M Tanaka T Kumagai T Terai G Kusumoto K Arima T Akita O Kashiwagi Y Abe K Gomi K Horiuchi H Kitamoto K Kobayashi T Takeuchi M Denning DW Galagan JE Nierman WC Yu J Archer DB Bennett JW Bhatnagar D Cleveland TE Fedorova ND Gotoh O Horikawa H Hosoyama A Ichinomiya M Igarashi R Iwashita K Juvvadi PR Kato M Kato Y Kin T Kokubun A Maeda H Maeyama N Maruyama J Nagasaki H Nakajima T Oda K Okada K Paulsen I Sakamoto K Sawano T Takahashi M Takase K Terabayashi Y Wortman JR Yamada O 《Nature》2005,438(7071):1157-1161
The genome of Aspergillus oryzae, a fungus important for the production of traditional fermented foods and beverages in Japan, has been sequenced. The ability to secrete large amounts of proteins and the development of a transformation system have facilitated the use of A. oryzae in modern biotechnology. Although both A. oryzae and Aspergillus flavus belong to the section Flavi of the subgenus Circumdati of Aspergillus, A. oryzae, unlike A. flavus, does not produce aflatoxin, and its long history of use in the food industry has proved its safety. Here we show that the 37-megabase (Mb) genome of A. oryzae contains 12,074 genes and is expanded by 7-9 Mb in comparison with the genomes of Aspergillus nidulans and Aspergillus fumigatus. Comparison of the three aspergilli species revealed the presence of syntenic blocks and A. oryzae-specific blocks (lacking synteny with A. nidulans and A. fumigatus) in a mosaic manner throughout the genome of A. oryzae. The blocks of A. oryzae-specific sequence are enriched for genes involved in metabolism, particularly those for the synthesis of secondary metabolites. Specific expansion of genes for secretory hydrolytic enzymes, amino acid metabolism and amino acid/sugar uptake transporters supports the idea that A. oryzae is an ideal microorganism for fermentation. 相似文献
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S Reboud M J Thomas 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1975,280(3):331-334
The mouse cervical cell response to progesterone, corticosterone, and androgens was studied in vitro and comparatively by grafts on males. Contrary to the exocervical cells which responded more or less to the three steroid hormones, the endocervical cells responded exclusively to progesterone even in an estrogen free system. This result suggests the existence in the mouse endocervical cells of specific receptors to progesterone and indicates that the squamons cells of the uterine cervix have a different response to steroid hormones depending on where these cells are located. 相似文献
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Zusammenfassung Ein Vergleich der Aminosäuresequenzen von menschlichen Wachstumshormonen und menschlichem Chorion-Somatomammotropin mit denjenigen von Prolactin zeigt, dass 26% des Rückstandes in allen drei Molekülen die gleiche Position hatten mit zusätzlichen 34% als möglichen Ersatz. Alle drei Hormone scheinen einen gleichen Ursprung zu haben. 相似文献
238.
Summary Methyl-nitrosourea, an unstable nitrosamide, exhibits a resorptive cancerogenic effect after shorttermed oral administration of high doses (4 times 40 mg/kg body weight). Induction time and localization of the observed tumours depend, among other things, on the dose and the pH of the cancerogen solution and on the age of animals. 相似文献
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