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181.
Marc Mathieu Christian Lehmann Alain Razaname Gabriele Tuchscherer 《Letters in Peptide Science》1997,4(2):95-100
The assembly of helical and -sheet peptide blocks containing reactive chain ends results inhighly branched chain architectures (locked-in folds) mimicking native tertiary structures.This molecular kit strategy allows to bypass the protein folding problem in protein de novodesign and gives access to protein mimetics of high thermodynamic stability. The validity ofthis concept is exemplified for the design and synthesis of locked-in folds mimicking the zincfinger and MHC folding motifs. 相似文献
182.
183.
Post-translational modifications are fundamental to processes controlling behaviour, including cellular signaling, growth and transformation. As the molecular basis of protein modifications in normal and disease processes are becoming better defined, so new strategies for designing therapeutic entities to control complex disease processes are emerging. 相似文献
184.
Mas Eric; Crotte Christian; Lecestre Dominique; Michalski Jean-Claude; Escribano Maria-Juana; Lombardo Dominique; Sadoulet Marie-Odile 《Glycobiology》1997,7(6):745-752
The fetoacinar pancreatic protein (FAP), characterized by themAb J28, is an oncofetal form of bile salt dependent lipase(BSDL), the expression of which is related to pancreatic differentiationand neoplastic processes. Because the J28 epitope, recognizedby imAb J28, is suggested to be dependent upon carbohydrates,we have attempted to gain information about the structure ofthis epitope. Indeed, treatment of FAP with sodium periodateabolished the reactivity of the protein to mAb J28, which demonstratesthe implication of oligosaccharides in the structure of theJ28 epitope. FAP offers both O-linked and N-linked carbohydratestructures, of which, as we have determined, one is involved.Peptides obtained after cyanogen bromide cleavage were desialylatedthen separated by affinity chromatography on an immobilizedpeanut agglutinin agarose column. The peptide retained on thiscolumn carried out the reactivity with the mAb J28. Althoughsome differences in amino acid analysis were observed, the N-terminalsequence of this peptide correlates with that of the C-terminalpart of the enzyme. Carbohydrate analysis of the peptide bearingthe J28 epitope revealed fucose, galactose, N-acetylgalactosamine,N-acetylglucosamine, and N-acetylneuraminic acid. The competitionobserved between mAb J28 and Ulex europaeus I lectin for bindingto the J28 epitope suggested that fucose residue a (12)linked to a galactose residue was implicated in the structureof the J28 epitope. Alternatively, the loss of the mAb J28 reactivityupon treatment of FAP either with bovine kidney or bovine epididymisfucosidase was observed indicating that fucose residues linkedat the 相似文献
185.
ZmEsr, a novel endosperm-specific gene expressed in a restricted region around the maize embryo 总被引:9,自引:1,他引:8
Hilde-Gunn Opsahl-Ferstad Erwan Le Deunff Christian Dumas Peter M. Rogowsky 《The Plant journal : for cell and molecular biology》1997,12(1):235-246
A novel endosperm-specific gene named Esr (e mbryo s urrounding r egion) has been isolated by differential display between early developmental stages of maize endosperms and embryos. It is expressed in a restricted region of the endosperm, surrounding the entire embryo at early stages (4 to 7 days after pollination, DAP) and ever-decreasing parts of the suspensor at subsequent stages. The expression starts at 4 DAP and is maintained until at least 28 DAP. A minimum of three Esr genes are present in the maize genome and at least two of them map to the short arm of chromosome 1 at position 56. The Esr genes contain no introns and show no significant nucleotide or amino acid sequence homologies to sequences in the databases. The open reading frames encode basic proteins of 14 kDa with presumptive signal peptides at their N-termini followed by a hypervariable and a conserved region. The gene product may play a role in the nutrition of the developing embryo or in the establishment of a physical barrier between embryo and endosperm. 相似文献
186.
187.
Christian Biémont Cristina Vieira Christine Hoogland Géraldine Cizeron Catherine Lœvenbruck Claude Arnault Jean-Pierre Carante 《Genetica》1997,100(1-3):161-166
To investigate the main forces controlling the containment of transposable elements (TE) in natural populations, we analyzed
the copia, mdg1, and 412 elements in various populations of Drosophila melanogaster and D. simulans. A lower proportion of
insertion sites on the X chromosome in comparison with the autosomes suggests that selection against the detrimental effects
of TE insertions is the major force containing TE copies in populations of Drosophila. This selection effect hypothesis is
strengthened by the absence of the negative correlation between recombination rate and TE copy number along the chromosomes,
which was expected under the alternative ectopic exchange model (selection against the deleterious rearrangements promoted
by recombination between TE insertions). A cline in 412 copy number in relation to latitude was observed among the natural
populations of D. simulans, with very high numbers existing in some local populations (around 60 copies in a sample from Canberra,
Australia). An apparent absence of selection effects in this Canberra sample and a value of transposition rate equal to 1–2
× 10-3 whatever the population and its copy number agree with the idea of recent but temporarily drastic TE movements in local populations.
The high values of transposition rate in D. simulans clearly disfavor the hypothesis that the low amount of transposable elements
in this species could result from a low transposition rate.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
188.
Akira F. Peters Madeleine J. H. van Oppen Christian Wiencke Wytze T. Stam Jeanine L. Olsen 《Journal of phycology》1997,33(2):294-309
Phylogenetic relationships in the Desmarestiales (Phaeophyceae) were inferred among the monotypic Arthrocladia (Arthrocladiaceae) and 27 isolates from Desmarestiaceae, representing 17 taxa of Desmarestia and the monotypic Antarctic genera Himantothallus and Phaeurus. Phaeurus and Arthrocladia were used as outgroups. Parsimony analyses of nuclear ribosomal DNA internal transcribed spacer (ITS1 and ITS2) sequences, in which gaps were both included and excluded, yielded well-resolved trees with a consistent general branching pattern. A parallel analysis of nine morphological and life-history characters and three ecological characters yielded a similar tree but provided little resolution in the terminal clades. The position of the monotypic Arthrocladia villosa within the Desmarestiales is consistent with monophyly for the order, but its position as the most primitive desmarestialean is not resolvable from the molecular data set. The basal position of Phaeurus, the Antarctic Desmarestia species, and Himantothallus is consistent with the hypothesis of a Southern Hemisphere origin for the family Desmarestiaceae. The more recent Northern Hemisphere “aculeata” clade evolved from an Antarctic ancestor. A “D. aculeata-like” species was ancestral to a lineage characterized by annual sporophytes with high sulfuric acid content, which radiated into many species, widely distributed in both hemispheres. Mapping of morphological and ecological characters onto the molecular tree confirm the informativeness of sulfuric acid-containing vacuoles and unilocular sporangial types. There is good congruence between phylogenetic tree topology and temperature impints in relation to biogeographic distribution, supporting the theory that temperature tolerance is a conservative trait. 相似文献
189.
Modeling of adaptations to physical training by using a recursive least squares algorithm 总被引:3,自引:0,他引:3
Busso Thierry; Denis Christian; Bonnefoy Regis; Geyssant Andre; Lacour Jean-Rene 《Journal of applied physiology》1997,82(5):1685-1693
Busso, Thierry, Christian Denis, Régis Bonnefoy,André Geyssant, and Jean-René Lacour. Modeling ofadaptations to physical training by using a recursive least squaresalgorithm. J. Appl. Physiol. 82(5):1685-1693, 1997.The present study assesses the usefulnessof a systems model with time-varying parameters for describing theresponses of physical performance to training. Data for two subjectswho undertook a 14-wk training on a cycle ergometer were used to testthe proposed model, and the results were compared with a model withtime-invariant parameters. Two 4-wk periods of intensive training wereseparated by a 2-wk period of reduced training and followed by a 4-wkperiod of reduced training. The systems input ascribed to the trainingdoses was made up of interval exercises and computed in arbitraryunits. The systems output was evaluated one to five times per week byusing the endurance time at a constant workload. The time-invariantparameters were fitted from actual performances by using the leastsquares method. The time-varying parameters were fitted by using arecursive least squares algorithm. The coefficients of determinationr2 were 0.875 and0.879 for the two subjects using the time-varying model, higher thanthe values of 0.682 and 0.666, respectively, obtained with thetime-invariant model. The variations over time in the model parametersresulting from the expected reduction in the residuals appearedgenerally to account for changes in responses to training. Such a modelwould be useful for investigating the underlying mechanisms ofadaptation and fatigue. 相似文献
190.