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排序方式: 共有386条查询结果,搜索用时 359 毫秒
191.
192.
Dreiss AN Silva N Richard M Moyen F Théry M Møller AP Danchin E 《Journal of evolutionary biology》2008,21(6):1814-1822
In many socially monogamous birds, both partners perform extrapair copulations (EPC). As this behaviour potentially inflicts direct costs on females, they are currently hypothesized to search for genetic benefits for descendants, either as 'good' or 'complementary' genes. Although these hypotheses have found some support, several studies failed to find any beneficial consequence of EPC, and whether this behaviour is adaptive to females is subject to discussion. Here, we test these two hypotheses in a natural population of blue tits by accounting for the effect of most parameters known to potentially affect extrapair fertilization. Results suggest that female body mass affected the type of extrapair genetic benefits obtained. Heavy females obtained extrapair fertilizations when their social male was of low quality (as reflected by sexual display) and produced larger extrapair than within-pair chicks. Lean females obtained extrapair fertilizations when their social mate was genetically similar, thereby producing more heterozygous extrapair chicks. Our results suggest that mating patterns may be condition-dependent. 相似文献
193.
Duplications are an important mechanism for the emergence of genetic novelties. Reports on duplicated genes are numerous, and mechanisms for polyploidization or local gene duplication are beginning to be understood. When a local duplication is studied, searches are usually done gene-by-gene, and the size of duplicated segments is not often investigated. Therefore, we do not know if the gene in question has duplicated alone or with other genes, implying that "en bloc" duplications are poorly studied. We propose a method for identification of "en bloc" duplication using mapping, phylogenetic and statistical analyses. We show that two segments present in the major histocompatibility complex (MHC) region of human chromosome 6 have resulted from an "en bloc" duplication that took place between divergence of amniotes and methaterian/eutherian separation. These segments contain members of the same multigenic families, namely olfactory receptors genes, genes encoding proteins containing B30.2 domain, genes encoding proteins containing immunoglobulin V domain and MHC class I genes. We will discuss the fact that olfactory receptors and MHC genes have undergone positive selection, which could have helped in fixation of the surrounding genes. 相似文献
194.
Agnieszka Sekowska Laurence Mulard Susanne Krogh Jane KS Tse Antoine Danchin 《BMC microbiology》2001,1(1):15-10
Background
Methylthioadenosine, the main by-product of spermidine synthesis, is degraded inBacillus subtilisas adenine and methylthioribose. The latter is an excellent sulfur source and the precursor of quorum-sensing signalling molecules. Nothing was known about methylthioribose recycling in this organism. 相似文献195.
We isolated seven microsatellite sequences from a library of recombinant clones in Rissa tridactyla (Laridae). We investigated their polymorphism in one population from France. Preliminary results indicate that these markers should prove valuable tools for the study of mating systems, population genetic structure and dispersal abilities in this seabird species. We present the results of cross‐species amplification for two seabird species: Uria aalge (Alcidae) and Stercorarius parasiticus (Stercorariidae). Some of the microsatellites isolated in R. tridactyla might be useful for studies on other seabird species. 相似文献
196.
Meglecz E Petenian F Danchin E D'Acier AC Rasplus JY Faure E 《Molecular ecology》2004,13(6):1693-1700
Microsatellite flanking regions have been compared in two butterfly species. Several microsatellite flanking regions showed high similarity to one another among different microsatellites within a same species, but very few similarities were found between species. This can be the consequence of either duplication/multiplication events involving large regions containing microsatellites or of microsatellites imbedded in minisatellite regions. The multiplication of microsatellites might also be linked to mobile elements. Furthermore, crossing over between nonhomologous microsatellites can lead to the exchange of the flanking regions between microsatellites. The same phenomenon was observed in both studied butterfly species but not in Aphis fabae (Hemiptera), which was screened at the same time using the same protocol. These findings might explain, at least partially, why microsatellite isolation in Lepidoptera has been relatively unsuccessful so far. 相似文献
197.
The spore coat protein CotA of Bacillus subtilis displays similarities with multicopper oxidases, including manganese oxidases and laccases. B. subtilis is able to oxidize manganese, but neither CotA nor other sporulation proteins are involved. We demonstrate that CotA is a laccase. Syringaldazine, a specific substrate of laccases, reacted with wild-type spores but not with DeltacotA spores. CotA may participate in the biosynthesis of the brown spore pigment, which appears to be a melanin-like product and to protect against UV light. 相似文献
198.
Multiple control of flagellum biosynthesis in Escherichia coli: role of H-NS protein and the cyclic AMP-catabolite activator protein complex in transcription of the flhDC master operon 下载免费PDF全文
Soutourina O Kolb A Krin E Laurent-Winter C Rimsky S Danchin A Bertin P 《Journal of bacteriology》1999,181(24):7500-7508
199.
MOTIVATION: To be fully and efficiently exploited, data coming from
sequencing projects together with specific sequence analysis tools need to
be integrated within reliable data management systems. Systems designed to
manage genome data and analysis tend to give a greater importance either to
the data storage or to the methodological aspect, but lack a complete
integration of both components. RESULTS: This paper presents a co-operative
computer environment (called Imagenetrade mark) dedicated to genomic
sequence analysis and annotation. Imagene has been developed by using an
object-based model. Thanks to this representation, the user can directly
manipulate familiar data objects through icons or lists. Imagene also
incorporates a solving engine in order to manage analysis tasks. A global
task is solved by successive divisions into smaller sub-tasks. During
program execution, these sub- tasks are graphically displayed to the user
and may be further re- started at any point after task completion. In this
sense, Imagene is more transparent to the user than a traditional
menu-driven package. Imagene also provides a user interface to display, on
the same screen, the results produced by several tasks, together with the
capability to annotate these results easily. In its current form, Imagene
has been designed particularly for use in microbial sequencing projects.
AVAILABILITY: Imagene best runs on SGI (Irix 6.3 or higher) workstations.
It is distributed free of charge on a CD-ROM, but requires some Ilog
licensed software to run. Some modules also require separate license
agreements. Please contact the authors for specific academic conditions and
other Unix platforms. CONTACT: imagene home page:
http://wwwabi.snv.jussieu.fr/imagene
相似文献
200.
Villani G Capitanio N Bizzoca A Palese LL Carlino V Tattoli M Glaser P Danchin A Papa S 《Biochemistry》1999,38(8):2287-2294
Various protolytic residues in subunit I of aa3-600 quinol oxidase of the aerobic Gram-positive Bacillus subtilis were mutagenized to nonpolar residues. Two of the mutations, Y284F and K304L, impaired the bioenergetic function of the microorganism. The Y284F mutation suppressed the electron-transfer activity of quinol oxidase and altered its interaction with CO and H2O2, thus showing destruction of the binuclear domain as observed for the bo3 quinol oxidase of Escherichia coli. The K304L mutation did not alter significantly the redox activity of the oxidase and its interaction with CO and H2O2 but suppressed the proton pumping activity of the enzyme. These results show that the K304 residue, which is invariantly conserved (as K or R) in practically all the sequences of the heme-copper oxidases so far available (around 100), is essential for the proton pumping activity of the oxidase. 相似文献