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排序方式: 共有590条查询结果,搜索用时 125 毫秒
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Juliette Morlon Martine Chartier Michel Bidaud Claude Lazdunski 《Molecular & general genetics : MGG》1988,211(2):231-243
Summary The complete nucleotide sequence of the colicinogenic plasmid ColA has been determined. The plasmid DNA consists of 6720 bp (molecular weight 4.48×106). Fifteen putative biological functions have been identified using the functional map previously determined. These include 11 genes and 3 DNA sites. Nine genes encode proteins of which 3 have been fully characterized. The replication region of ColA coding for RNAI and RNAII is highly homologous to that of ColE1 andClo DF13. The same holds true for the site-specific recombination region containing palindromic symmetry and involved in stable maintenance of the plasmids. A high percentage of homology has been detected for putative mobility proteins encoded by ColA and ColE1. The exclusion proteins are also highly homologous. 相似文献
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N L Huq S M Rambaud L C Teh A D Davies B McCulloch M M Trotter G E Chapman 《Biochemical and biophysical research communications》1985,129(3):714-720
Osteocalcin (the 6,000 dalton Mr gamma-carboxyglutamate-containing protein of bone) has been detected in acid extracts of bones of the extinct class of New Zealand ratite birds, the moas, using a radioimmunoassay for sheep osteocalcin. The immunoreactive osteocalcin of the extracts of two of these bones (the fibulae from two specimens of Pachyornis elephantopus found in South Island swamps) has been fractionated by gel filtration chromatography and reversed-phase high performance liquid chromatography, and behaves in a manner characteristic of osteocalcin from modern bones. Carbon-14 dating of bones and gizzard contents found in association with these specimens indicates approximate ages of 3,600 and 7,400 years respectively. 相似文献
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Giovanni Sgubin Didier Swingedouw Juliette Mignot Gregory Alan Gambetta Benjamin Bois Harilaos Loukos Thomas Noël Philippe Pieri Iñaki García de Cortázar-Atauri Nathalie Ollat Cornelis van Leeuwen 《Global Change Biology》2023,29(3):808-826
Evaluating the potential climatic suitability for premium wine production is crucial for adaptation planning in Europe. While new wine regions may emerge out of the traditional boundaries, most of the present-day renowned winemaking regions may be threatened by climate change. Here, we analyse the future evolution of the geography of wine production over Europe, through the definition of a novel climatic suitability indicator, which is calculated over the projected grapevine phenological phases to account for their possible contractions under global warming. Our approach consists in coupling six different de-biased downscaled climate projections under two different scenarios of global warming with four phenological models for different grapevine varieties. The resulting suitability indicator is based on fuzzy logic and is calculated over three main components measuring (i) the timing of the fruit physiological maturity, (ii) the risk of water stress and (iii) the risk of pests and diseases. The results demonstrate that the level of global warming largely determines the distribution of future wine regions. For a global temperature increase limited to 2°C above the pre-industrial level, the suitable areas over the traditional regions are reduced by about 4%/°C rise, while for higher levels of global warming, the rate of this loss increases up to 17%/°C. This is compensated by a gradual emergence of new wine regions out of the traditional boundaries. Moreover, we show that reallocating better-suited grapevine varieties to warmer conditions may be a viable adaptation measure to cope with the projected suitability loss over the traditional regions. However, the effectiveness of this strategy appears to decrease as the level of global warming increases. Overall, these findings suggest the existence of a safe limit below 2°C of global warming for the European winemaking sector, while adaptation might become far more challenging beyond this threshold. 相似文献
6.
Juliette Gaëtan Sébastien Halary Maxime Millet Cécile Bernard Charlotte Duval Sahima Hamlaoui Amandine Hecquet Muriel Gugger Benjamin Marie Neha Mehta David Moreira Fériel Skouri-Panet Cynthia Travert Elodie Duprat Julie Leloup Karim Benzerara 《Environmental microbiology》2023,25(3):751-765
The formation of intracellular amorphous calcium carbonates (iACC) has been recently observed in a few cultured strains of Microcystis, a potentially toxic bloom-forming cyanobacterium found worldwide in freshwater ecosystems. If iACC-forming Microcystis are abundant within blooms, they may represent a significant amount of particulate Ca. Here, we investigate the significance of iACC biomineralization by Microcystis. First, the presence of iACC-forming Microcystis cells has been detected in several eutrophic lakes, indicating that this phenomenon occurs under environmental conditions. Second, some genotypic (presence/absence of ccyA, a marker gene of iACC biomineralization) and phenotypic (presence/absence of iACC) diversity have been detected within a collection of strains isolated from one single lake. This illustrates that this trait is frequent but also variable within Microcystis even at a single locality. Finally, one-third of publicly available genomes of Microcystis were shown to contain the ccyA gene, revealing a wide geographic and phylogenetic distribution within the genus. Overall, the present work shows that the formation of iACC by Microcystis is common under environmental conditions. While its biological function remains undetermined, this process should be further considered regarding the biology of Microcystis and implications on the Ca geochemical cycle in freshwater environments. 相似文献
7.
We show with a model that variation in environmental stress between generations facilitates the evolution of stress resistance through assortative mating. Stress induces delayed maturation of susceptible phenotypes, segregating their fertile period from resistant phenotypes. Assortment of mates enhances the responsiveness of populations to natural selection by inflating genetic variance. Thus, positive selection and inflated genetic variance in stressful environments can cause a strong evolutionary increase in resistance. By contrast, benign environments do not segregate phenotypes, and the random mating among phenotypes deflates genetic variance, leading to a weaker response to selection against resistance, assuming that resistance is costly. When environments vary randomly from benign to stressful, populations respond asymmetrically to negative and positive selection. This asymmetry (1) accelerates fixation of a resistance allele if resistance is generally favoured (stressful generations more frequent) but delays the loss of the allele if it is generally disfavoured (benign generations more frequent), and (2) it can push a resistance allele to fixation even when long‐term costs modestly exceed benefits. When resistance alleles pleiotropically delay mating, stress‐induced random mating has complementary effects. Serial autocorrelation in the stressor amplifies these effects. These results suggest a novel mechanism for the persistence of resistance polymorphisms. 相似文献
8.
Roles of bovine serum albumin and copper in the assay and stability of ammonia monooxygenase activity in vitro. 总被引:1,自引:1,他引:0
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We investigated the effects of bovine serum albumin (BSA) on both the assay and the stability of ammonia-oxidizing activity in cell extracts of Nitrosomonas europaea. Ammonia-dependent O2 uptake activity of freshly prepared extracts did not require BSA. However, a dependence on BSA developed in extracts within a short time. The role of BSA in the assay of ammonia-oxidizing activity apparently is to absorb endogenous free fatty acids which are present in the extracts, because (i) only proteins which bind fatty acids, e.g., BSA or beta-lactoglobulin, supported ammonia-oxidizing activity; (ii) exogenous palmitoleic acid completely inhibited ammonia-dependent O2 uptake activity; (iii) the inhibition caused by palmitoleic acid was reversed only by proteins which bind fatty acids; and (iv) the concentration of endogenous free palmitoleic acid increased during aging of cell extracts. Additionally, the presence of BSA (10 mg/ml) or CuCl2 (500 microM) stabilized ammonia-dependent O2 uptake activity for 2 to 3 days at 4 degrees C. The stabilizing effect of BSA or CuCl2 was apparently due to an inhibition of lipolysis, because both additives inhibited the increase in concentrations of free palmitoleic acid in aging extracts. Other additives which are known to modify lipase activity were also found to stabilize ammonia-oxidizing activity. These additives included HgCl2, lecithin, and phenylmethylsulfonyl fluoride. 相似文献
9.
Felicja Meisel-Mikoajczyk Alicja Rokosz Anna Sawicka-Grzelak J. Zuijderduijn Ilse Beckmann Juliette Paelinck 《Journal of applied microbiology》1984,57(3):405-411
Phenol/water-extracted lipopolysaccharide and a fraction HM, extracted with acetate buffer pH 2.0, from Bacteroides fragilis strain 62/73 are antigenically different as shown by immunodiffusion, passive haemagglutination, haemagglutination inhibition and preliminary chemical investigations. Biological activity, assessed with the local Shwartzmann reaction, was demonstrated for the lipopolysaccharide whereas antigen HM was almost inactive in this test. HM is immunogenic in rabbits. Antibodies against HM were detected in seven out of ten sera of healthy humans. 相似文献
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