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981.
Levasseur A Orlando L Bailly X Milinkovitch MC Danchin EG Pontarotti P 《Biological reviews of the Cambridge Philosophical Society》2007,82(4):551-572
To demonstrate that a given change in the environment has contributed to the emergence of a given genotypic and phenotypic shift during the course of evolution, one should ask to what extent such shifts would have occurred without environmental change. Of course, such tests are rarely practical but phenotypic novelties can still be correlated to genomic shifts in response to environmental changes if enough information is available. We surveyed and re-evaluated the published data in order to estimate the role of environmental changes on the course of species and genomic evolution. Only a few published examples clearly demonstrate a causal link between a given environmental change and the fixation of a genomic variant resulting in functional modification (gain, loss or alteration of function). Many others suggested a link between a given phenotypic shift and a given environmental change but failed to identify the underlying genomic determinant(s) and/or the associated functional consequence(s). The proportion of genotypic and phenotypic variation that is fixed concomitantly with environmental changes is often considered adaptive and hence, the result of positive selection, even though alternative causes, such as genetic drift, are rarely investigated. Therefore, the second aim herein is to review evidence for the mechanisms leading to fixation. 相似文献
982.
983.
984.
Rehab Kamel Simone Garcia Frank Lezoualc'h Rodolphe Fischmeister Sylviane Muller Johan Hoebeke Pierre Eftekhari 《BMC developmental biology》2007,7(1):34
Background
The presence of functional 5-HT4 receptors in human and its involvement in neonatal lupus erythematosus (NLE) have prompted us to study the receptor expression and role during embryogenesis. Earlier we managed to demonstrate that female BALB/c mice immunized against the second extracellular loop (SEL) of the 5-HT4 receptor gave birth to pups with heart block. To explain this phenomenon we investigated the expression of 5-HT4 receptors during mouse embryogenesis. At the same time we looked whether the consequence of 5-HT4 receptor immunomodulation observed earlier is in relation to receptor expression. 相似文献985.
Farrokh Modabber Pierre A Buffet Els Torreele Geneviéve Milon Simon L Croft 《Kinetoplastid biology and disease》2007,6(1):3
Background
A meeting was organized by Drugs for Neglected Diseases initiative (DNDi) and the Institute Pasteur (IP), Paris, to review the treatment for all forms of cutaneous leishmaniasis (CL) and to propose a strategy for the development of new efficacious and affordable treatments. 相似文献986.
Barthélémy RM Grino M Pontarotti P Casanova JP Faure E 《Cellular & molecular biology letters》2007,12(4):573-583
Chaetognaths constitute a small marine phylum of approximately 120 species. Two classes of both 18S and 28S rRNA gene sequences have been evidenced in this phylum, even though significant intraindividual variation in the sequences of rRNA genes is unusual in animal genomes. These observations led to the hypothesis that this unusual genetic characteristic could play one or more physiological role(s). Using in situ hybridization on the frontal sections of the chaetognath Spadella cephaloptera, we found that the 18S Class I genes are expressed in the whole body, with a strong expression throughout the gut epithelium, whereas the expression of the 18S Class II genes is restricted to the oocytes. Our results could suggest that the paralog products of the 18S Class I genes are probably the "housekeeping" 18S rRNAs, whereas those of class II would only be essential in specific tissues. These results provide support for the idea that each type of 18S paralog is important for specific cellular functions and is under the control of selective factors. 相似文献
987.
Alazard D Badillo C Fardeau ML Cayol JL Thomas P Roldan T Tholozan JL Ollivier B 《Extremophiles : life under extreme conditions》2007,11(1):33-39
A new alkaliphilic and moderately halophilic, strictly anaerobic, fermentative bacterium (strain IMP-300T) was isolated from a groundwater sample in the zone of the former soda lake Texcoco in Mexico. Strain IMP-300T was Gram-positive, non-sporulated, motile and rod-shaped. It grew within a pH range from 7.5 to 10.5, and an optimum at 9.5.
The organism was obligately dependent on the presence of sodium salts. Growth showed an optimum at 35°C with absence of growth
above 45°C. It fermented peptone and a few amino acids, preferentially arginine and ornithine, with production of acetate,
propionate, and ammonium. Its fatty acid pattern was mainly composed of straight chain saturated, unsaturated, and cyclopropane
fatty acids. The G + C content of genomic DNA was 40.0 mol%. Analysis of the 16S rRNA gene sequence indicated that the new
isolate belongs to the genus Tindallia, in the low G + C Gram-positive phylum. Phylogenetically, strain IMP-300T has Tindallia californiensis, as closest relative with a 97.5% similarity level between their 16S rDNA gene sequences, but the DNA–DNA re-association
value between the two DNAs was only 42.2%. On the basis of differences in genotypic, phenotypic, and phylogenetic characteristics,
strain IMP-300T is proposed as a new species of the genus Tindallia, T. texcoconensis sp. nov. (type strain IMP-300T = DSM 18041T = JCM 13990T). 相似文献
988.
Spatial Analysis of Production by Macrophytes,Phytoplankton and Epiphyton in a Large River System under Different Water-Level Conditions 总被引:1,自引:0,他引:1
Relative contributions by macrophytes, epiphyton and phytoplankton to total primary production was estimated in a large (∼300 km2) widening of the St. Lawrence River (Canada), over a 2-year period with contrasting flows and water levels. Spatially-explicit
estimates of whole-system production were obtained by combining field measurements with remotely sensed data and empirical
models using GIS. Primary production and relative contributions of each producer type differed markedly between open-water
and wetland habitats. Spatial differences within each habitat arose from interactions between physical factors including light,
water depth, water transit times and wind stress. At the whole-system level, annual primary production represented 105 gC m−2 y−1, divided roughly equally among phytoplankton (34%), submerged macrophytes (27%), emergent macrophytes (23%) and epiphyton
(16%). A 10% decrease in annual flows and 1-m decline in water levels between 2000 and 2001 resulted in a 50% loss of marsh
habitat, a 60% increase in phytoplankton production in the open-water zone, and in the appearance of conspicuous filamentous
algal mats. Low water levels induced substantial shifts in the spatial configuration and relative importance of primary producers
although total river primary production remained stable between years. 相似文献
989.
Pascal Philibert Audrey Stoessel Wei Wang Annie-Paule Sibler Nicole Bec Christian Larroque Jeffery G Saven Jérôme Courtête Etienne Weiss Pierre Martineau 《BMC biotechnology》2007,7(1):81
Background
Intrabodies are defined as antibody molecules which are ectopically expressed inside the cell. Such intrabodies can be used to visualize or inhibit the targeted antigen in living cells. However, most antibody fragments cannot be used as intrabodies because they do not fold under the reducing conditions of the cell cytosol and nucleus. 相似文献990.
Navet R Mathy G Douette P Dobson RL Leprince P De Pauw E Sluse-Goffart C Sluse FE 《Journal of proteome research》2007,6(1):25-33
Cold acclimation induces an adaptative increase in respiration in brown adipose tissue (BAT). A comparative analysis by two-dimensional differential in-gel electrophoresis of mitochondrial protein patterns found in rat control and cold-acclimated BAT was performed. A total of 58 proteins exhibiting significant differences in their abundance was unambiguously identified. Proteins implicated in the major catabolic pathways were up-regulated as were ATP synthase and mitofilin. Moreover, these results support the fact that adipocytes can balance their ATP synthesis and their heat production linked to UCP1-sustained uncoupling. 相似文献