Search results for "REDUCTASE"
showing 10 items of 798 documents
Nitric oxide synthase isozymes. Characterization, purification, molecular cloning, and functions.
1994
Three isozymes of nitric oxide (NO) synthase (EC 1.14.13.39) have been identified and the cDNAs for these enzymes isolated. In humans, isozymes I (in neuronal and epithelial cells), II (in cytokine-induced cells), and III (in endothelial cells) are encoded for by three different genes located on chromosomes 12, 17, and 7, respectively. The deduced amino acid sequences of the human isozymes show less than 59% identity. Across species, amino acid sequences for each isoform are well conserved (> 90% for isoforms I and III, > 80% for isoform II). All isoforms use L-arginine and molecular oxygen as substrates and require the cofactors NADPH, 6(R)-5,6,7,8-tetrahydrobiopterin, flavin adenine…
Sequences of isopenicillin N synthetase genes suggest horizontal gene transfer from prokaryotes to eukaryotes
1990
Evolutionary distances between bacterial and fungal isopenicillin N synthetase (IPNS) genes have been compared to distances between the corresponding 5S rRNA genes. The presence of sequences homologous to the IPNS gene has been examined in DNAs from representative prokaryotic organisms and Ascomycotina. The results of both analyses strongly support two different events of horizontal transfer of the IPNS gene from bacteria to filamentous fungi. This is the first example of such a type of transfer from prokaryotes to eukaryotes.
Does Down's syndrome support the homocysteine theory of atherogenesis?
2006
Abstract Down syndrome (DS) is generally considered as an “atheroma-free model”. In this preliminary study, we investigated homocysteine, folate and Vitamin B 12 levels in 13 DS patients (male, average age 60 years) and 20 age-matched individuals. We also studied lipid fractions, and polymorphisms for Cystothionine β-synthase (CBS), 5,10-methyl-tetrahydro-folate reductase (MTHFR) and apolipoprotein E (Apo-E) genes. However, DS patients with the MTHFR TT genotype showed an increased of plasma homocysteine (tHcy). Our results indicate that this group of “healthy old” Down syndrome patients, although showing some classical biochemical risk factors for atherosclerosis, did not suffer clinical c…
The longevity assurance homologue of yeast lag1 (Lass) gene family (Review)
2009
The Lass gene family contains a group of highly conserved genes that are found in eukaryotic species. The founding member, lag1, was discovered in a screen for yeast longevity genes. Subsequently, lag1 homologs were discovered in other organisms including six mammalian paralogs. All Lass genes encode a highly conserved Lag1 domain and many also have an additional Hox domain. Lass proteins are ceramide synthases and therefore are critical for ceramide biosynthesis. Ceramide synthase is also a critical enzyme in the sphingolipid biosynthetic pathway. As ceramide and sphingolipids are key intermediates in diverse cellular processes such as cell growth, apoptosis, and stress response and may al…
Quantitative Detection of the nosZ Gene, Encoding Nitrous Oxide Reductase, and Comparison of the Abundances of 16S rRNA, narG , nirK , and nosZ Genes…
2006
ABSTRACT Nitrous oxide (N 2 O) is an important greenhouse gas in the troposphere controlling ozone concentration in the stratosphere through nitric oxide production. In order to quantify bacteria capable of N 2 O reduction, we developed a SYBR green quantitative real-time PCR assay targeting the nosZ gene encoding the catalytic subunit of the nitrous oxide reductase. Two independent sets of nosZ primers flanking the nosZ fragment previously used in diversity studies were designed and tested (K. Kloos, A. Mergel, C. Rösch, and H. Bothe, Aust. J. Plant Physiol. 28:991-998, 2001). The utility of these real-time PCR assays was demonstrated by quantifying the nosZ gene present in six different …
Recovery of mutants impaired in pathogenicity after transposition of Impala in Fusarium oxysporum f.sp. melonis
2000
The ability of transposon impala to inactivate genes involved in pathogenicity was tested in Fusarium oxysporum f. sp. melonis. Somatic excision of an impala copy inserted in the nitrate reductase-encoding niaD gene was positively selected through a phenotypic assay based on the restoration of nitrate reductase activity. Independent excision events were analyzed molecularly and shown to carry reinsertedimpala in more than 70% of the cases. Mapping of reinserted impala elements on large NotI-restriction fragments showed that impala transposes randomly. By screening 746 revertants on plants, a high proportion (3.5%) of mutants impaired in their pathogenic potential was recovered. According t…
Colonization of America by Drosophila subobscura: association between Odh gene haplotypes, lethal genes and chromosomal arrangements.
2004
The colonization of America by Drosophila subobscura has been a unique exper iment in nature that has allowed us to explore the effects of evolution on a continental scale. To analyze this evolutionary event, nucleotide sequences of the Odh (Octanol dehydrogenase) gene were obtained for 43 lethal chromosomal lines from colonizing populations of North America and 5 from South America, in addition to 5 chromosomal lines from Europe with different viabilities and 2 from laboratory marker stocks. Since 10 different Odh haplotypes were found in America, the minimum number of colonizers would be 5 (or 3 mated females). Only one Odh haplotype was found in American O(5) inversions confirming that o…
Human cytochrome P450 reductase can act as a source of endogenous oxidative DNA damage and genetic instability.
2005
Studies with repair-deficient mice and other experiments suggest that oxidative DNA modifications are generated in all types of cells even under physiological conditions and that this type of endogenous DNA damage contributes to spontaneous cancer incidence. However, the cellular sources of reactive oxygen species that are relevant for nuclear oxidative DNA damage are largely unknown. Here, we report that expression of human NADPH-cytochrome P450 reductase (hOR) in cultured V79 Chinese hamster cells gives rise to elevated basal levels of oxidative purine modifications after depletion of glutathione. Also, the basal levels of micronuclei are increased in the hOR-expressing cells, and again t…
Genotype and Allele Frequencies of Drug-Metabolizing Enzymes and Drug Transporter Genes Affecting Immunosuppressants in the Spanish White Population
2013
Interpatient variability in drug response can be widely explained by genetically determined differences in metabolizing enzymes, drug transporters, and drug targets, leading to different pharmacokinetic and/or pharmacodynamic behaviors of drugs. Genetic variations affect or do not affect drug responses depending on their influence on protein activity and the relevance of such proteins in the pathway of the drug. Also, the frequency of such genetic variations differs among populations, so the clinical relevance of a specific variation is not the same in all of them. In this study, a panel of 33 single nucleotide polymorphisms in 14 different genes (ABCB1, ABCC2, ABCG2, CYP2B6, CYP2C19, CYP2C…
Spatiotemporal Variations in the Abundance and Structure of Denitrifier Communities in Sediments Differing in Nitrate Content
2017
Spatial and temporal variations related to hydric seasonality in abundance and diversity of denitrifier communities were examined in sediments taken from two sites differing in nitrate concentration along a stream Doñ