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1.
Bruna Tadolini Diana Fiorentini Laura Landi Luciana Cabrini 《Free radical research》1989,5(4):245-252
To find experimental conditions to selectively study the propagation phase of lipoperoxidation we studied the lipoperoxidation, catalyzed by FeCl2, of liposomes in a buffering condition where Fe2+ autoxidation and oxygen active species generation does not occur. Liposomes from egg yolk phosphatidylcholine. prepared by vortex mixing, do not oxidize Fe2+: on the contrary they oxidize Fe2+ when prepared by ultrasonic irradiation. Dimyristoyl phosphatidylcholine liposomes prepared by ultrasonic irradiation do not oxidize Fe2+. During sonication polyunsaturated fatty acid residues autoxidize and lipid hydroperoxides (LOOH) are generated. Only when LOOH are present in the liposimes Fe2+ oxidizes and its rate of oxidation depends on the amount of LOOH in the assay. The reaction results in the generation of both LOOH and thiobarbituric acid reactive material (TBAR): it is inhibited by butylated hydroxytoluene and has a acidic pH optimum; it is not inhibited by catalase and OH' scavengers. The reaction studied. thus, appears to be the chain branching and propagation phase of lipoperoxidation. When we studied the dependence of Fe2+ oxidation, LOOH and TBAR generation on FeCl2 concentration, we observed that at high FeCl2 concentrations the termination phase of lipoperoxidation was prevalent. Thus. by selecting the appropriate FeCl2 concentration the proposed experimental system allows study of either the propagation or the termination phase of lipoperoxidation. 相似文献
2.
Luciana A. Haddad Regina C. Mingroni-Netto Angela M. Vianna-Morgante Sérgio D. J. Pena 《Human genetics》1996,97(6):808-812
Ever since the identification of the genetic cause of fragile X syndrome as the expansion of an unstable trinucleotide sequence,
several diagnostic strategies have evolved from molecular studies. However, we still lack a simple test suitable for population
screening. We have therefore developed a nonisotopic polymerase chain reaction (PCR)-based technique for the identification
of fragile X full mutations among men, with easy visualization of the PCR products on silver-stained polyacrylamide gels.
The technique consists of PCR amplification with primers that flank the trinucleotide repeats, with a product of 557 bp for
the (CGG)29 allele. Conditions were established such that full mutations failed to amplify and were thus identified with 98% sensitivity
compared with Southern blot analysis. To produce an indispensable internal control we added to the reaction a third primer,
internal to this fragment, allowing the multiplex amplification of a monomorphic band corresponding to a CG-rich stretch 147
bp upstream of the polymorphic region. In trials involving 41 patients and 74 controls, the PCR-based test here described
showed specificity of more than 98.6%, accuracy of 99% and a sensitivity of 98%. Thus, although not suitable for medical diagnosis,
it constitutes a useful tool for screening for the fragile X syndrome in populations of mentally retarded males.
Received: 31 May 1995 / Revised: 4 October 1995 相似文献
3.
4.
Hans Achenbach Werner Kohl Wolfgang Wachter Hans Reichenbach 《Archives of microbiology》1978,116(3):253-257
Besides carotenoids a complex of flexirubin-type pigments was isolated from the gliding bacteriumCytophaga johnsonae Cy j1 and separated into 6 components, which partly containe chlorine. In spite of the fact that these components still consist of pigment mixtures, the gross structures of 18 new flexirubin-type pigments could be deduced by spectroscopic and chemical investigations. The results open insights into biosynthesis and structural variety of the flexirubins, the novel non-isoprenoid pigments recently found inFlexibacter elegans.Non-Standard Abbreviations FT
Fourier transformation
- HPLC
high pressure liquid chromatography
- M+
molecular ion
- M/M
resolution of mass spectrometer
- mu
mass units
-
t
R
retention time
- TLC
thin layer chromatography
Part 16: Investigations on metabolites of microorganisms. Part. XV: H. Achenbach, W. Kohl, H. Reichenbach: Die Hauptpigmente vonCytophaga johnsonae. Tetrahedron Lett.1977, 1061. Part XIV: H. Achenbach, J. Witzke: Totalsynthese des Flexirubindimethylethers. Angew. Chem.89, 198 (1977); Angew. Chem. Int. Ed. Engl.16, 191 (1977) 相似文献
5.
Summary A male patient with mental retardation and typical clinical features of 10p trisomy syndrome was found to have a duplication of the short arm of chromosome 10 attached to the short arm of the Y chromosome.Quantitative evaluation of nine red cell enzymes showed significantly increased activity levels of HK1 and, to a lesser extent, of PK, PGI, 6PGD, and G6PD. It is suggested that the HK1 locus may be in the 10pterp12 region. The increased levels of HK1 could affect other erythrocyte metabolic pathways slowing down the physiological rate of cellular senescence and result in increased activity levels of other cell-age-dependent enzymes. 相似文献
6.
Streptomyces michiganensis strain Tü 1074, was isolated from a Tunesian soil sample and produces in liquid medium an antibiotic active pigment complex. Besides mitomycin A the separation of this complex yielded a nonactive phenoxazone, which hitherto has not been described in the literature. In contrary to all known phenoxazones from microorganisms the new compound lacks a 2-amino-function. The production of this phenoxazone could be enhanced by optimizing the conditions of fermentation. 相似文献
7.
Butterworth MB Edinger RS Silvis MR Gallo LI Liang X Apodaca G Frizzell RA Fizzell RA Johnson JP 《American journal of physiology. Renal physiology》2012,302(5):F581-F590
Expression of the epithelial sodium channel (ENaC) at the apical membrane of cortical collecting duct (CCD) principal cells is modulated by regulated trafficking mediated by vesicle insertion and retrieval. Small GTPases are known to facilitate vesicle trafficking, recycling, and membrane fusion events; however, little is known about the specific Rab family members that modify ENaC surface density. Using a mouse CCD cell line that endogenously expresses ENaC (mpkCCD), the channel was localized to both Rab11a- and Rab11b-positive endosomes by immunoisolation and confocal fluorescent microscopy. Expression of a dominant negative (DN) form of Rab11a or Rab11b significantly reduced the basal and cAMP-stimulated ENaC-dependent sodium (Na(+)) transport. The greatest reduction in Na(+) transport was observed with the expression of DN-Rab11b. Furthermore, small interfering RNA-mediated knockdown of each Rab11 isoform demonstrated the requirement for Rab11b in ENaC surface expression. These data indicate that Rab11b, and to a lesser extent Rab11a, is involved in establishing the constitutive and cAMP-stimulated Na(+) transport in mpkCCD cells. 相似文献
8.
9.
Genotypic diversity of oscillatoriacean strains belonging to the genera Geitlerinema and Spirulina determined by 16S rDNA restriction analysis 总被引:1,自引:0,他引:1
Genotypic diversity of several cyanobacterial strains mostly isolated from marine or brackish waters, belonging to the genera Geitlerinema and Spirulina, was investigated by amplified 16S ribosomal DNA restriction analysis and compared with morphological features and response to salinity. Cluster analysis was performed on amplified 16S rDNA restriction profiles of these strains along with profiles obtained from sequence data of five Spirulina-like strains, including three representatives of the new genus Halospirulina. Our strains with tightly coiled trichomes from hypersaline waters could be assigned to the Halospirulina genus. Among the uncoiled strains, the two strains of hypersaline origin clustered together and were found to be distant from their counterparts of marine and freshwater habitat. Moreover, another cluster, formed by alkali-tolerant strains with tightly coiled trichomes, was well delineated. 相似文献
10.
Photosynthetic and phylogenetic primers for detection of anoxygenic phototrophs in natural environments. 总被引:3,自引:0,他引:3
Primer sets were designed to target specific 16S ribosomal DNA (rDNA) sequences of photosynthetic bacteria, including the green sulfur bacteria, the green nonsulfur bacteria, and the members of the Heliobacteriaceae (a gram-positive phylum). Due to the phylogenetic diversity of purple sulfur and purple nonsulfur phototrophs, the 16S rDNA gene was not an appropriate target for phylogenetic rDNA primers. Thus, a primer set was designed that targets the pufM gene, encoding the M subunit of the photosynthetic reaction center, which is universally distributed among purple phototrophic bacteria. The pufM primer set amplified DNAs not only from purple sulfur and purple nonsulfur phototrophs but also from Chloroflexus species, which also produce a reaction center like that of the purple bacteria. Although the purple bacterial reaction center structurally resembles green plant photosystem II, the pufM primers did not amplify cyanobacterial DNA, further indicating their specificity for purple anoxyphototrophs. This combination of phylogenetic- and photosynthesis-specific primers covers all groups of known anoxygenic phototrophs and as such shows promise as a molecular tool for the rapid assessment of natural samples in ecological studies of these organisms. 相似文献