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101.
Characterization of a frequent polymorphism in the coding sequence of the Tp53 gene in colonic cancer patients and a control population 总被引:2,自引:0,他引:2
Sylviane Olschwang Pierre Laurent-Puig Anne Vassal Rémy-J. Salmon Gilles Thomas 《Human genetics》1991,86(4):369-370
Summary We describe a simple method for characterizing a frequent polymorphism (that subsitutes an arginine for a proline) in the coding sequence of the Tp53 gene in patients with colonic cancer and in a control population. We could find no evidence that this polymorphism is associated with a marked predisposition to colorectal cancer. 相似文献
102.
103.
Ronald J. Hill Margaret R. Mott Fujiko Watt Theodora Fifis P. Anne Underwood 《Chromosoma》1986,94(6):441-448
An antigen making a major contribution to the immune response to Drosophila melanogaster chromatin resides primarily on a nonhistone charge-class family of proteins of Mr 74,000. Immunofluorescence detects this antigen at interbands, puffs and diffuse bands of D. melanogaster salivary chromosomes isolated without exposure to acid fixatives, and on nucleoplasmic ribonucleoprotein droplets. In the electron microscope, gold labelling reveals the binding of monoclonal antibodies specific for the antigen at chromosomal loci generally bearing putative ribonucleoprotein (RNP) particles. However, the locus 3C 11–12 is remarkable in that it bears putative RNP particles but is virtually unlabelled, suggesting protein specificity at different active loci. 相似文献
104.
Transposon Mutagenesis and Excision of R′ Plasmids by Conjugative, Chimeric Plasmid pUW942 in Extra-Slow-Growing Rhizobium japonicum Strains 下载免费PDF全文
Transposons Tn501 (specifying mercury resistance) and Tn7 (specifying resistance to trimethoprim and streptomycin) were introduced into extra-slow-growing Rhizobium japonicum by conjugal transfer of the 82 kilobase chimeric plasmid pUW942. Mercury-resistant transconjugants were obtained at a frequency of 10−7 to 10−9. The transfer frequency of streptomycin resistance was lower than that of mercury resistance, and Tn7 was relatively unstable. pUW942 was not maintained as an autonomously replicating plasmid in R. japonicum strains. However, some of the Hgr transconjugants from the RJ19FY, RJ17W, and RJ12S strains acquired antibiotic markers of the vector plasmid pUW942. Southern hybridization of plasmid and chromosomal DNA of R. japonicum strains with 32P-labeled pUW942 and pAS8Rep-1, the same plasmid as pUW942 except that it does not contain Tn501, revealed the formation of cointegrates between pUW942 and the chromosome of R. japonicum. More transconjugants with only Tn501 insertions in plasmids or the chromosome were obtained in crosses with strains RJ19FY and RJ17W than with RJ12S. These retained stable Hgr both in plant nodules and under nonselective in vitro growth conditions. One of the RJ19FY and two of the RJ12S Hgr transconjugants with vector plasmid-chromosome cointegrates conjugally transferred plasmids of 82, 84 or 86, and 90 kilobases, respectively, into plasmidless Escherichia coli C. These plasmids strongly hybridized to pUW942 and EcoRI digests of total DNA of each respective R. japonicum strain but not to indigenous plasmid DNA of the R. japonicum strains. These R′ plasmids consisted of pUW942-specific EcoRI fragments and an additional one or two new fragments derived from the R. japonicum chromosome. 相似文献
105.
The O-methyl substituents of aromatic compounds constitute a C1 growth substrate for a number of taxonomically diverse anaerobic acetogens. In this study, strain TH-001, an O-demethylating obligate anaerobe, was chosen to represent this physiological group, and the carbon flow when cells were grown on O-methyl substituents as a C1 substrate was determined by 14C radiotracer techniques. O-[methyl-14C]vanillate (4-hydroxy-3-methoxy-benzoate) was used as the labeled C1 substrate. The data showed that for every O-methyl carbon converted to [14C]acetate, two were oxidized to 14CO2. Quantitation of the carbon recovered in the two products, acetate and CO2, indicated that acetate was formed in part by the fixation of unlabeled CO2. The specific activity of 14C in acetate was 70% of that in the O-methyl substrate, suggesting that only one carbon of acetate was derived from the O-methyl group. Thus, it is postulated that the carboxyl carbon of the product acetate is derived from CO2 and the methyl carbon is derived from the O-methyl substituent of vanillate. The metabolism of O-[methyl-14C]vanillate by strain TH-001 can be described as follows: 314CH3OC7H5O3 + CO2 + 4H2O → 14CH3COOH + 214CO2 + 10H+ + 10e- + 3HOC7H5O3. 相似文献
106.
Uniformly fatty livers from orotic acid-fed rats secreted almost no very low density lipoproteins (VLDL) but normal amounts of nascent high density lipoproteins (HDL) accumulated in perfusates. When lecithin:cholesterol acyltransferase (LCAT) was inhibited, nascent HDL were uniformly discoidal and lacked cholesteryl esters. Lipid and apoprotein compositions of nascent HDL from normal and fatty livers were similar whether LCAT was inhibited or not. Apolipoprotein B-100 was not detected in perfusates of uniformly fatty livers, but small amounts of apolipoprotein B-48 were present in HDL2 fractions. Nascent lipoproteins were not seen in Golgi compartments, but lipid-rich particles were clearly evident in endoplasmic reticulum cisternae adjacent to the cis face of the Golgi complex, suggesting that orotic acid blocks VLDL secretion by preventing translocation of nascent particles from the endoplasmic reticulum to the cis Golgi compartment. The accumulation of normal amounts of discoidal HDL in liver perfusates despite virtual absence of triglyceride-rich lipoproteins in Golgi secretory compartments, the space of Disse, and the perfusate is inconsistent with the concept that nascent HDL are exclusively a product of surface remnants cast off during lipolysis of chylomicrons and VLDL. 相似文献
107.
Christian Boucher Anne Martinel Patrick Barberis Genevieve Alloing Claudine Zischek 《Molecular & general genetics : MGG》1986,205(2):270-275
Summary A class of avirulent mutants of the plant pathogenic bacterium Pseudomonas solanacearum, strain GMI1000, resistant to acridine orange (Acrr), harbour a deletion of over 85 kb in their genome. This deletion affects, a1,000 kb megaplasmid which has previously been shown to be present in most of the strains of this species. In addition at least 11 out of 13 independent Tn5 insertions, leading to loss of virulence, are located on the megaplasmid. Nine of them are present in the region which is deleted from the Acrr mutants. These results suggest that the majority of virulence genes identified so far are plasmid borne. 相似文献
108.
109.
Phorbol 12,13-Dibutyrate Increases Tyrosine Hydroxylase Activity in the Superior Cervical Ganglion of the Rat 总被引:3,自引:3,他引:0
Phorbol 12,13-dibutyrate (PDBu) increased the production of 3,4-dihydroxyphenylalanine (DOPA) in the superior cervical ganglion of the rat. This effect occurred without a detectable lag and persisted for at least 90 min of incubation. The action of PDBu was half-maximal at a concentration of approximately 0.1 microM; at high concentrations, PDBu produced about a twofold increase in DOPA accumulation. PDBu increased DOPA production in decentralized ganglia and in ganglia incubated in a Ca2+-free medium. The action of PDBu was additive with the actions of dimethylphenylpiperazinium, muscarine, and 8-Br-cyclic AMP, all of which also increase DOPA accumulation, and was not inhibited by the cholinergic antagonists hexamethonium (3 mM) and atropine (6 microM). Finally, PDBu did not increase the content of cyclic AMP in the ganglion. Thus, the action of PDBu does not appear to be mediated by the release of neurotransmitters from preganglionic nerve terminals, by the stimulation of cholinergic receptors in the ganglion, or by an increase in ganglionic cyclic AMP. PDBu also increased the incorporation of 32Pi into tyrosine hydroxylase. PDBu activates protein kinase C, which in turn may phosphorylate tyrosine hydroxylase and increase the rate of DOPA synthesis in the ganglion. 相似文献
110.