1,872 research outputs found
Les éléments constitutifs des terrains biologiques et les immunités naturelles
No full textPech J. L. Les éléments constitutifs des terrains biologiques et les immunités naturelles. In: Bulletin de l'Académie Vétérinaire de France tome 118 n°2, 1965. pp. 63-68
Menaces sur votre vie / par le professeur J.-L. Pech
No full textCollection : L'air du tempsContient une table des matièresAvec mode text
A reliable system for the transformation of cantaloupe charentais melon (Cucumis melo L. var. cantalupensis) leading to a majority of diploid regenerants
No full textAn efficient system of transformation leading to a majority of transformed diploid plants from leaf explants of Cucumis melo L. var. Cantalupensis (cv. Védrantais) was developed. Several regeneration protocols using cotyledon or leaf explants were analysed with particular emphasis on the regeneration efficiency and the ploidy level of the regenerated melon plants. The use of leaf explants excised from 10 day-old seedlings, cultured in Murashige and Skoog's medium supplemented with 1 mM 6-benzylaminopurine (BAP) and 1 mM 6-(g,g-dimethylallylamino)-purine (2iP), resulted in a high regeneration frequency (73%). In these conditions, more than 84% of the regenerated plants were found to be diploid. Addition of an Agrobacterium-mediated transformation step did not significantly change the percentage (81.8%) of diploid plants regenerated. This protocol was successfully used to produce diploid transgenic melon plants expressing the antisense ACC oxidase gene, encoding ACC oxidase which catalyses the last step of ethylene biosynthesis. Ethylene production and ACC oxidase activity of the leaf explants from transgenic plants was reduced by more than 80% as compared to the control untransformed tissues. This transformation/regeneration method could be routinely used for the introduction of other genes of interest in melon
P. et G. Pinchemel : La face de la terre. M. Germain et al. : Le guide de la Haute Savoie. Pech P. et Regnauld H. : Géographie physique. Demangeot J. : Les milieux naturels du globe. Lliboutry L. : Sciences géométriques et télédétection. Guichard F. : Porto, la ville dans sa région.
No full textP. et G. Pinchemel : La face de la terre. M. Germain et al. : Le guide de la Haute Savoie. Pech P. et Regnauld H. : Géographie physique. Demangeot J. : Les milieux naturels du globe. Lliboutry L. : Sciences géométriques et télédétection. Guichard F. : Porto, la ville dans sa région.. In: Revue de géographie alpine, tome 81, n°1, 1993. p. 113
P. et G. Pinchemel : La face de la terre. M. Germain et al. : Le guide de la Haute Savoie. Pech P. et Regnauld H. : Géographie physique. Demangeot J. : Les milieux naturels du globe. Lliboutry L. : Sciences géométriques et télédétection. Guichard F. : Porto, la ville dans sa région.
No full textP. et G. Pinchemel : La face de la terre. M. Germain et al. : Le guide de la Haute Savoie. Pech P. et Regnauld H. : Géographie physique. Demangeot J. : Les milieux naturels du globe. Lliboutry L. : Sciences géométriques et télédétection. Guichard F. : Porto, la ville dans sa région.. In: Revue de géographie alpine, tome 81, n°1, 1993. p. 113
3D model related to the publication: A pangolin (Manidae, Pholidota, Mammalia) from the French Quercy phosphorites (Pech du Fraysse, Saint-Projet, Tarn-et-Garonne, late Oligocene, MP 28)
No full textInternational audienceThis contribution contains the 3D model described and figured in the following publication: Crochet, J.-Y., Hautier, L., Lehmann, T., 2015. A pangolin (Manidae, Pholidota, Mammalia) from the French Quercy phosphorites (Pech du Fraysse, Saint-Projet, Tarn-et-Garonne, late Oligocene, MP 28). Palaeovertebrata 39(2)-e4. doi: 10.18563/pv.39.2.e
Localization, analysis and evolution of transposed human immunoglobulin VK genes
No full textThe localization of Vκ gene regions to chromosome 2, on which the κ locus is located, and to other chromosomes is described. The Vκ genes that have been transposed to other chromosomes are called orphons. The finding of two new Vκ genes on chromosome 22 is reported. A Vκ II gene of this region and two Vκ I genes of the Chr 1 and the cos 118 regions were sequenced. The two Vκ I orphon sequences and two others that had been determined previously were 97.5% identical, indicating that they may have evolved from a common ancestor by amplification. A model of the evolution of the human Vκ orphons is discussed.
Author Keywords: Human-rodent cell hybrids; cosmids; restriction maps; ligation artifacts; orphon; recombinant DNA
Abbreviations: aa, amino acid(s); bp, base pair(s); Chr1, Vκ gene-containing regions of chromosomes 1; Chr22, Vκ gene-containing regions of chromosomes 22; FR, framework regions; CDR, complementary determining regions; kb, kilo-base(s) or 1000 bp; L, L′, parts of a leader gene segment; m219-1, the first subclone of the cosmid clone cos 219; orphon, Vκ gene outside the κ locus on chromosome 2pl2; SSC, 0.15 M NaCl, 0.015 M Na3-citrate, pH 7.6; V, variable gene segments; J, joining gene segments; C, constant gene segments; Vκ I to Vκ IV, variable gene segments of immunoglobulin light chains of the κ type belonging to subgroups I to IV; for reasons of simplicity Vκ gene segments are generally called Vκ gene
Climacteric fruit ripening: Ethylene-dependent and independent regulation of ripening pathways in melon fruit
No full textCantaloupe melons have a typical climacteric behaviour with ethylene playing a major role in the regulation of the ripening process and affecting the ripening rate. Crossing of Cantaloupe Charentais melon with a non-climacteric melon indicated that the climacteric character is genetically dominant and conferred by two duplicated loci only. However, other experiments made by crossing two non-climacteric melons have generated climacteric fruit, indicating that different and complex genetic regulation exists for the climacteric character. Suppression of ethylene production by antisense ACC oxidase RNA in Charentais melon has shown that, while many ripening pathways were regulated by ethylene (synthesis of aroma volatiles, respiratory climacteric and degreening of the rind), some were ethylene-independent (initiation of climacteric, sugar accumulation, loss of acidity and coloration of the pulp). Softening of the flesh comprised both ethylene-dependent and independent components that were correlated with differential regulation of cell wall degrading genes. These results indicate that climacteric (ethylene-dependent) and non-climacteric (ethylene-independent) regulation coexist during climacteric fruit ripening. In addition, ethylenesuppressed melons allowed demonstrating that the various ethylene-dependent events exhibited differential sensitivity to ethylene and that ethylene was promoting sensitivity to chilling injury. Throughout this review, the data generated with melon are compared with those obtained with tomato and other fruit
Metabolic and molecular events occurring during chromoplast biogenesis
No full textChromoplasts are nonphotosynthetic plastids that accumulate carotenoids. They derive from other plastid forms, mostly chloroplasts. The biochemical events responsible for the interconversion of one plastid form into another are poorly documented. However, thanks to transcriptomics and proteomics approaches, novel information is now available. Data of proteomic and biochemical analysis revealed the importance of lipid metabolism and carotenoids biosynthetic activities. The loss of photosynthetic activity was associated with the absence of the chlorophyll biosynthesis branch and the presence of proteins involved in chlorophyll degradation. Surprisingly, the entire set of Calvin cycle and of the oxidative pentose phosphate pathwaypersisted after the transition from chloroplast to chromoplast. The role of plastoglobules in the formation and organisation of carotenoid-containing structures and that of the Or gene in the control of chromoplastogenesis are reviewed. Finally, using transcriptomic data, an overview is given the expression pattern of a number of genes encoding plastid-located proteins during tomato fruit ripening
Use of homologous and heterologous gene expression profiling tools to characterize transcription dynamics during apple fruit maturation and ripening
No full textAbstract Background Fruit development, maturation and ripening consists of a complex series of biochemical and physiological changes that in climacteric fruits, including apple and tomato, are coordinated by the gaseous hormone ethylene. These changes lead to final fruit quality and understanding of the functional machinery underlying these processes is of both biological and practical importance. To date many reports have been made on the analysis of gene expression in apple. In this study we focused our investigation on the role of ethylene during apple maturation, specifically comparing transcriptomics of normal ripening with changes resulting from application of the hormone receptor competitor 1-Methylcyclopropene. Results To gain insight into the molecular process regulating ripening in apple, and to compare to tomato (model species for ripening studies), we utilized both homologous and heterologous (tomato) microarray to profile transcriptome dynamics of genes involved in fruit development and ripening, emphasizing those which are ethylene regulated. The use of both types of microarrays facilitated transcriptome comparison between apple and tomato (for the later using data previously published and available at the TED: tomato expression database) and highlighted genes conserved during ripening of both species, which in turn represent a foundation for further comparative genomic studies. The cross-species analysis had the secondary aim of examining the efficiency of heterologous (specifically tomato) microarray hybridization for candidate gene identification as related to the ripening process. The resulting transcriptomics data revealed coordinated gene expression during fruit ripening of a subset of ripening-related and ethylene responsive genes, further facilitating the analysis of ethylene response during fruit maturation and ripening. Conclusion Our combined strategy based on microarray hybridization enabled transcriptome characterization during normal climacteric apple ripening, as well as definition of ethylene-dependent transcriptome changes. Comparison with tomato fruit maturation and ethylene responsive transcriptome activity facilitated identification of putative conserved orthologous ripening-related genes, which serve as an initial set of candidates for assessing conservation of gene activity across genomes of fruit bearing plant species.</p
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