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51.
Claude Sauvage Jean-François Rumigny Michel Maitre 《Molecular and cellular biochemistry》1991,107(1):65-77
Summary Three G proteins from human brain membranes were purified to near homogeneity by conventional techniques including preparative
electrophoresis. These G proteins were characterized by their ability to bind GTP, GDP and GTP analogs. Two of these proteins
have molecular weights of 50,000 (G50) and 36,000 (G36), as determined on SDS-gels. G36 was ADP-ribosylated by pertussis toxin. Thus, G50 could represent a Gsα subunit, whereas G36 could be Giα or Goα. G50 was phosphorylated by cAMP dependent protein kinase and protein kinase C. G36 was phosphorylated by a protein kinase independent of calcium and phospholipid, a proteolytic product of protein kinase C,
analogous to protein kinase M. Phosphorylation of G36 by this protein kinase induced a dramatic decrease in its GTPase activity. The third G protein, of molecular weight 22,000
probably belongs to the group of monomeric G proteins possessing functional similarities withras gene products. The regulation of G proteins involving calcium-dependent and independent pathways is delineated. 相似文献
52.
Monique Berthelon Catherine Caillaud Françoise Rey Philippe Labrune Dominique Melle Josué Feingold Jean Frézal Marie-Louise Briard Jean-Pierre Farriaux Pierre Guibaud Hubert Journel Bernard Le Marec Nicole Maurin Jean-Louis Nivelon Henri Plauchu Jean-Marie Saudubray Philippe Tron Jean Rey Arnold Münnich Stanislas Lyonnet 《Human genetics》1991,86(4):355-358
Summary A total of 252 chromosomes from 126 patients with phenylalanine hydroxylase (PAH) deficiencies were analyzed for both mutant genotypes and restriction fragment length polymorphism (RFLP) haplotypes at the PAH locus. The mutant genes studied originated either from Western Europe (116 alleles) or from Mediterranean countries (136 alleles). Only 27% of all mutant alleles were found to carry identified mutations, particularly mutations at codon 252 (2.3%), 261 (7.5%), 280 (6.3%), 408 (3.5%) and at the splice donor site of intron 12 (6.3%). The mutant genotypes were associated with RFLP haplotypes 7, 1, 38, 2 and 3 at the PAH locus respectively. Except for the splice mutation of intron 12, these associations were preferential, but not exclusive, since the other four mutations were found on the background of at least two RFLP haplotypes. These results, together with the observation that 85% of PAH deficient patients are heterozygotes for their mutant genotypes, emphasize the great heterogeneity of PAH deficiencies in Mediterranean countries and hamper systematic DNA testing for carrier status in this population. 相似文献
53.
Clinical and molecular heterogeneity of phenylalanine hydroxylase deficiencies in France 总被引:20,自引:10,他引:10
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Franoise Rey Monique Berthelon Catherine Caillaud Stanislas Lyonnet Vronique Abadie Flicienne Blandin-Savoja Josu Feingold Jean-Marie Saudubray Jean Frzal Arnold Munnich Jean Rey 《American journal of human genetics》1988,43(6):914-921
RFLPs of 68 normal and 74 mutant alleles at the phenylalanine hydroxylase (PAH) locus were determined in 37 French kindreds. A total of 23 haplotypes, including 18 normal and 16 mutant alleles, were observed. Two-thirds of all mutant alleles were confined within only four haplotypes, while the last third was accounted for by 12 haplotypes, including eight haplotypes absent from Caucasian pedigrees reported thus far. Several mutant haplotypes were present in typical phenylketonuria only, others were present in variants only, and some were present in both. In addition, a particular mutant haplotype (haplotype 2) was found to harbor different mutations in our series, resulting in either typical phenylketonuria or in mild hyperphenylalaninemias. The diploid combination of so many mutant haplotypes in PAH-deficient patients and of compound heterozygosity at the PAH locus in southern Europe might account for the broad spectrum of individual phenotypes observed in France. 相似文献
54.
Michel Sylvestre Robert Massé Christianne Ayotte François Messier Johanne Fauteux 《Applied microbiology and biotechnology》1985,21(3-4):192-195
Summary Several bacterial strains that can oxidize mono- and dichlorinated biphenyls with one unsubstituted ring have already been described. The major route for this biodegradation leads ultimately to the corresponding chlorobenzoic acid, but several other minor chlorinated metabolites that might possibly be of concern for the environment have also been described previously. Since none of the bacterial strains that are able to oxidize these chlorinated biphenyls in pure culture are known to degrade chlorobenzoic acid, the oxidation of these substrates by axenic cultures always generates chlorobenzoates plus several other metabolites. In the present study, we have estimated the biodegradation of 4-chlorobiphenyl (4CB) by a two-membered bacterial culture containing one strain able to grow on 4CB and to transform it into 4-chlorobenzoate (4CBA) and one strain able to degrade 4CBA. The results were encouraging, since it was shown that the degradation of 4CB was more rapid and complete with the double bacterial culture. 相似文献
55.
Summary The peptidergic system in the optic ganglia of Astacus leptodactylus is characterized by the immunocytochemical application of 15 antisera raised against biologically active peptides of vertebrates and invertebrates. Positive reactions were found with anti-FMRFamide, antiMSH, anti-vasotocin, anti-gastrin, anti-CCK, anti-oxytocin, anti-secretin, anti-glucagon and anti-GIP. Based on immunochemical reaction and localization it is possible to distinguish 30 cell groups. Only part of these cell groups is found in the known classical neurosecretory cell regions. This observation demonstrates a more extensive peptidergic system than formerly recognized. The morphology of this peptidergic system suggests that one part is neurohormonal and the other part neurotransmitter-like or neuromodulatory. 相似文献
56.
Yasuyuki Kurihara Nobumoto Miyashita Kazuo Moriwaki Michael L. Petras François Bonhomme Wang Su Cho Sei-ichi Kohno 《Immunogenetics》1985,22(3):211-218
Allelic distributions of Thy-1, Ly-l, and Ly-2 antigens in wild mice are characteristic of each Mus musculus subspecies. Eastern mice (M.m.molossinus, M.mmusculus, M.m.castaneus, M.m.bactrianus) express the Thy-1.1 antigen, whereas Western mice (M.m. domesticus, M.m.brevirostris) express the Thy-1.2. All mice from wild populations examined in this survey express the Ly-1.2. The Ly-2.1 is distributed in Eastern mice and some Western mice, and the Ly-2.2 is found in the remaining Western mice. Allelic distributions of these antigens were also examined in two other species, Mus spretus and Mus spicilegus. Allelic constitutions of Thy-1 and Ly-1 in these species are similar to those of Eastern mice. Some M.spicilegus, however, express the Ly-1.1 antigen. This antigenic type is not found in M.musculus. Some Eastern mice related to M.m.castaneus react weakly to Ly-1.2-specific and Ly-2.1-specific monoclonal antibodies in both the complement-mediated cytotoxicity test and the absorption test. These results suggest that M.m.castaneus has unique alleles in the Ly-1 and Ly-2 loci. 相似文献
57.
From their recombination properties, tandem rho- mutants of the mitochondrial genome of Saccharomyces cerevisiae were divided into two categories. In crosses between PIF-independent rho- and rho+ strains, the recombination frequency is low and similar in PIF/pif and pif/pif diploids. In crosses between PIF-dependent rho- and rho+ strains, the recombination frequency is stimulated 10-50 times in PIF/pif diploids and is drastically decreased in pif/pif diploids. These results suggest that a recombinogenic signal is present in the mitochondrial (mt) DNA of PIF-dependent rho- clones. This signal is not recognized in pif mutants. Sequence analysis of a series of small (<300 bp) overlapping tandem rho- genomes located in the ery region of the 21S rRNA gene led us to identify an essential element of this signal within a 41-bp A+T sequence exhibiting over 26 bp a perfect dyad symmetry. However the recombinogenic signal is not sequence-specific since the sequence described above does not characterize PIF-dependent rho- clones located in the oli1 region. Our results rather suggest that the recombinogenic signal is related to the topology of rho- DNA. Denaturated sites in the double helix or cruciform structures elicited by local negative supercoiling might be preferred sites of the initiation of recombination. 相似文献
58.
59.
François Lieutier 《Journal of invertebrate pathology》1984,43(1):21-31
The protein concentrations of fat body and ovaries in Ips sexdentatus either uninfected or infected by Parasitaphelenchus sp., P. sexdentati, or Contortylenchus diplogaster were measured at various stages of insect development, from preswarming maturation to the first oviposition (24 hr after mating). Weight variations of the fat body and ovaries in insects infected by C. diplogaster show the same evolution as those observed in uninfected insects, but at a much lower level. Fat body proteins in uninfected insects reach their minimum level during swarming, but they remain fairly constant throughout the maturation of the first egg. After dropping shortly after swarming, the ovarian protein level in such insects increases in two stages during ovarian maturation. The first stage, which corresponds to a slow protein incorporation, takes place during the first 12 hr after mating. During the second stage, i.e., beyond 12 hr, a significant level of proteins is rapidly incorporated into the ovaries. In insects infected by Parasitaphelenchus fat body proteins are reduced and protein incorporation into the ovaries is reduced; Parasitaphelenchus would thus affect at least some proteins required for ovarian maturation in their host. Fat body protein levels are even more affected by C. diplogaster than by Parasitaphelenchus, while incorporation into ovaries seems to be less affected in spite of slower ovarian growth. C. diplogaster might thus essentially act both upon proteins which are not required for the ovarian maturation of their host and upon nonproteinaceous substances that are required for such maturation. Results are discussed in relation to the possible mode of action of parasitic nematodes. 相似文献
60.