Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

HIV-positive patients may experience erectile dysfunction and Viagra may be prescribed as a treatment. Viagra is processed by the P450 enzyme system and may negatively interact with other drugs, including protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTI). Protease inhibitors and delavirdine may increase Viagra levels and increase the risk of side effects. The NNRTIs efavirenz and nevirapine may lower levels of Viagra and reduce its effectiveness. The combination of Viagra with amyl nitrate can cause life-threatening drops in blood pressure.
...
PMID:A note about Viagra. 1136 23

Transgenic plants of Arabidopsis bearing the spinach (Spinacia oleracea) nitrite reductase (NiR, EC 1.7.7.1) gene that catalyzes the six-electron reduction of nitrite to ammonium in the second step of the nitrate assimilation pathway were produced by use of the cauliflower mosaic virus 35S promoter and nopaline synthase terminator. Integration of the gene was confirmed by a genomic polymerase chain reaction (PCR) and Southern-blot analysis; its expression by a reverse transcriptase-PCR and two-dimensional polyacrylamide gel electrophoresis western-blot analysis; total (spinach + Arabidopsis) NiR mRNA content by a competitive reverse transcriptase-PCR; localization of NiR activity (NiRA) in the chloroplast by fractionation analysis; and NO(2) assimilation by analysis of the reduced nitrogen derived from NO(2) (NO(2)-RN). Twelve independent transgenic plant lines were characterized in depth. Three positive correlations were found for NiR gene expression; between the total NiR mRNA and total NiR protein contents (r = 0.74), between the total NiR protein and NiRA (r = 0.71), and between NiRA and NO(2)-RN (r = 0.65). Of these twelve lines, four had significantly higher NiRA than the wild-type control (P < 0.01), and three had significantly higher NO(2)-RN (P < 0.01). Each of the latter three had one to two copies of spinach NiR cDNA per haploid genome. The NiR flux control coefficient for NO(2) assimilation was estimated to be about 0.4. A similar value was obtained for an NiR antisense tobacco (Nicotiana tabacum cv Xanthi XHFD8). The flux control coefficients of nitrate reductase and glutamine synthetase were much smaller than this value. Together, these findings indicate that NiR is a controlling enzyme in NO(2) assimilation by plants.
...
PMID:Nitrite reductase gene enrichment improves assimilation of NO(2) in Arabidopsis. 1140 1

Oenococcus oeni, the main species which induces malolactic fermentation in wine, uses arginine via the arginine deiminase (ADI) pathway. Using degenerated primers, two specific probes, one for ornithine transcarbamoylase (OTC) and the other for carbamate kinase (CK), were synthesized. These made it possible to clone and sequence a cluster containing genes encoding ADI (arcA), OTC (arcB) and CK (arcC). In addition, sequence analysis upstream of the arcA gene revealed the presence of an open reading frame (orf229) whose 3'-end was only 101 bp-distant from the start codon of the arcA gene and showed similarity with members of the FNR (regulation for fumarate and nitrate reduction) and CRP (cAMP receptor protein) family of transcriptional regulators. Moreover, a putative binding site for such regulators lies in the promoter region of the arcA gene. Induction of the arc cluster by arginine was studied first at the enzymatic level. The activities of the three enzymes strongly increased when cells were grown in the presence of the amino acid. In addition, the influence of arginine on gene transcription was monitored by RT-PCR (reverse transcriptase-polymerase chain reaction). Expression of the three arc genes, and particularly that of arcA, was positively affected by arginine supplementation and thus confirmed the enzymatic results. Moreover, transcription of the putative CRP-like gene orf229 was also stimulated by arginine. These data suggest that the protein encoded by orf229 could be a CRP-like regulator involved in the metabolism of O. oeni.
...
PMID:The arcABC gene cluster encoding the arginine deiminase pathway of Oenococcus oeni, and arginine induction of a CRP-like gene. 1160 85

Nitrate is an essential element for plant growth, both as a primary nutrient in the nitrogen assimilation pathway and as an important signal for plant development. The uptake of nitrate from the soil and its translocation throughout the plant has been the subject of intensive physiological and molecular studies. Using a reverse genetic approach, the AtNRT2.1 gene has been shown to be involved in the inducible component of the high-affinity nitrate transport system in Arabidopsis. The Arabidopsis Genome Initiative has released nearly the whole genome sequence of Arabidopsis, allowing the identification of a small NRT2 multigene family in this species. Thus, we investigated the phylogenetic relationship between NRT2 proteins belonging to several kingdoms and compared the structure of the different members of the Arabidopsis family. We analyzed, by semiquantitative reverse transcriptase-polymerase chain reaction, the expression pattern of each gene depending on plant organ and development or nutritional status, and compared the relative level of each gene by real-time polymerase chain reaction. We also evaluated the significance of each paralog on the basis of the relative levels of gene expression. The results are discussed in relation with distinct roles for the individual members of the AtNRT2 family.
...
PMID:Analysis of the NRT2 nitrate transporter family in Arabidopsis. Structure and gene expression. 1206 27

Melatonin, a major hormone of pineal gland, was recently shown to attenuate acute gastric lesions induced by strong irritants because of the scavenging of free radicals but its role in ulcer healing has been little investigated. In this study we compared the effects of intragastric (i.g.) administration of melatonin and its precursor, L-tryptophan, with or without concurrent treatment with luzindole, a selective antagonist of melatonin MT2 receptors, on healing of chronic gastric ulcers induced by serosal application of acetic acid (ulcer area 28 mm2). The involvement of endogenous prostaglandins (PG), nitric oxide (NO) and sensory nerves in ulcer healing action of melatonin and L-tryptophan was studied in rats treated with indomethacin and NG-nitro-L-arginine (L-NNA) to suppress, respectively, cyclo-oxygenases (COX) and NO synthases or in those with functionally deactivated sensory nerves with capsaicin. The influence of melatonin on gastric secretion during ulcer healing was tested in separate group of rats with gastric ulcer equipped with gastric fistulas (GF). At day 8 and 15 upon the ulcer induction, the area of gastric ulcers was measured by planimetry, the mucosal blood flow (GBF) was determined by H2-gas clearance technique and gastric luminal NO2-/NO3- levels was assessed by Griess reaction. Plasma melatonin and gastrin levels were measured by specific radioimmunoassay (RIA). Biopsy mucosal samples were taken for expression of constitutive NO-synthase (cNOS) and inducible NOS (iNOS) by reverse transcriptase-polymerase chain reaction (RT-PCR). Melatonin (2.5-20 mg/kg-d i.g.) and L-tryptophan (25-100 mg/kg-d i.g.) dose-dependently accelerated ulcer healing, the dose inhibiting by 50% (ED50) of ulcer area being 10 and 115 mg/kg, respectively. This inhibitory effect of melatonin (10 mg/kg-d i.g.) and L-tryptophan (100 mg/kg-d i.g.) on ulcer healing was accompanied by a significant rise in the GBF at ulcer margin and an increase of plasma melatonin. luminal NO2-/NO3- and plasma gastrin levels. Gastric acid and pepsin outputs were significantly inhibited during the ulcer healing in melatonin-treated gastric mucosa as compared with those in vehicle-treated animals. Luzindole abolished completely the healing effects of melatonin and L-tryptophan and attenuated significantly the rise in plasma gastrin evoked by the hormone and its precursor. Indomethacin (5 mg/kg-d i.p). that blocked PG biosynthesis by 90% or L-NAME (20 mg/kg i.v), inhibitor of NOS. that suppressed luminal NO release, attenuated significantly melatonin and L-tryptophan-induced acceleration of ulcer healing and accompanying rise in GBF at ulcer margin and luminal NO release. The melatonin-induced acceleration of ulcer healing, hyperemia at ulcer margin and increase in the release of NO were enhanced when L-arginine but not D-arginine was added to L-NAME. The ulcer healing and the GBF effects of melatonin and L-tryptophan were significantly impaired in rats with capsaicin-induced denervation of sensory nerves and both, ulcer healing and the hyperemia at ulcer margin were restored in these rats by addition of exogenous CGRP to melatonin and L-tryptophan. Expression of cNOS mRNA was detected by RT-PCR in the intact gastric mucosa as well as at the edge of gastric ulcers treated with both, vehicle and melatonin, while iNOS mRNA that was undetectable in the intact gastric mucosa, appeared during ulcer healing and especially this was strongly up-regulated in the melatonin-treated gastric mucosa. We conclude that (1) exogenous melatonin and that derived from its precursor, L-tryptophan, accelerate ulcer healing probably via interaction with MT2 receptors; (2) this ulcer healing action is caused by an enhancement by melatonin of the microcirculation at the ulcer margin possibly mediated by COX-derived PG and NO because of overexpression of iNOS and (3) gastrin, which exhibits trophic activity in the gastric mucosa and calcitonin gene related peptide (CGRP), released from sensory nerves, may also contribute to the ulcer healing action of melatonin.
...
PMID:Role of prostaglandins, nitric oxide, sensory nerves and gastrin in acceleration of ulcer healing by melatonin and its precursor, L-tryptophan. 1207 98

Effects of lead nitrate (LN), a hepatic mitogen, on hepatic gene expressions of lanosterol 14alpha-demethylase (CYP51) and the sterol regulatory element binding proteins (SREBP-1a, SREBP-1c and SREBP-2), which are thought to be transcription factors for hepatic CYP51 gene, were examined by the methods of Northern blot and/or real time reverse transcriptase-polymerase chain reaction (RT-PCR). In both immature (4-week-old) and mature (7-week-old) rats, LN treatment resulted in definite increases in hepatic gene expression of CYP51 at 12 h and in the liver weight at 48 h. As for transcription factors for the CYP51 gene, enhanced gene expression of SREBP-2 was observed 6-12 h after LN treatment, whereas no enhanced gene expression of other SREBPs, SREBP-1a and SREBP-1c, was observed at any time after the treatment; for SREBP-1a, there was no significant change; for SREPB-1c, there was a drastic decrease. In addition, the serum total cholesterol level was increased 12 h after LN treatment to 7-week-old rats, and the increased level was maintained at least up to 48 h later. In the present study, we demonstrate for the first time that LN, a heavy-metal ion, activates the expression of the SREBP-2 and CYP51 genes without decreasing the serum total cholesterol level and further suggest that only SREBP-2 among SREBPs might play an important role in the LN-enhanced CYP51 gene expression.
...
PMID:Altered gene expression of hepatic lanosterol 14alpha-demethylase (CYP51) in lead nitrate-treated rats. 1211 Oct 4

In order to evaluate the in situ degradative capabilities of microorganisms in an underground reactor facility housing two flowthrough columns filled with aquifer soil, we examined the distribution and phylogeny of gene transcripts encoding enzymes capable of catalyzing the cleavage of the chlorinated aromatic ring during transformation of the main pollutant, chlorobenzene. Initial biostimulation of the autochthonous bacteria in the originally anaerobic reactor columns was achieved by injecting nitrate and oxygen in the form of H(2)O(2). Two broad-range primer pairs were used for reverse transcriptase PCR (RT-PCR) of partial subunit genes of chlorocatechol 1,2-dioxygenase and catechol 2,3-dioxygenase from RNA directly extracted from different groundwater and aquifer samples. Samples retrieved from the lowermost sections of the reactor columns, which were operated in upflow mode, were positive for the presence of chlorocatechol 1,2-dioxygenase and catechol 2,3-dioxygenase mRNA. On the other hand, chlorocatechol 1,2-dioxygenase RT-PCR products were detected in a larger part of each reactor column, up to a zone 5.5 m above the bottom. Phylogenetic analyses of these chlorocatechol 1,2-dioxygenase sequences clearly separated them into two main clusters, one of which was closely affiliated with the broad-spectrum chlorocatechol 1,2-dioxygenase from Pseudomonas chlororaphis RW71. Analysis of sequences obtained from RT-PCR products amplified with catechol 2,3-dioxygenase primers revealed that their closest relative was the chlorocatechol 2,3-dioxygenase gene cbzE from Pseudomonas putida GJ31 (A. E. Mars, J. Kingma, S. R. Kaschabek, W. Reineke, and D. B. Janssen, J. Bacteriol. 181:1309-1318, 1999), with sequence similarities between 97.8 and 99.0%.
...
PMID:Expression of chlorocatechol 1,2-dioxygenase and chlorocatechol 2,3-dioxygenase genes in chlorobenzene-contaminated subsurface samples. 1262 Aug 18

Synechococcus sp. strain RF-1 is a unicellular freshwater cyanobacterium that fixes N(2) aerobically and exhibits a circadian rhythm for nitrogenase activity under a light-dark regimen. Synechococcus sp. strain RF-1 also utilizes nitrate, nitrite, or ammonium for growth. Under the diazotrophic growth, the nitrate uptake in Synechococcus sp. strain RF-1 was induced by nitrate or nitrite but repressed by ammonium. In contrast, a prominent nitrate reductase (NR) activity was detected in diazotrophically grown cells using the reduced methyl viologen assay. The NR activity was not inhibited by ammonium and only slightly enhanced by nitrate. The different expression patterns of nitrate uptake and NR in Synechococcus sp. strain RF-1 were reflected in general at the transcript level determined by reverse transcriptase PCR. Under both nitrate-induced and uninduced conditions, the in situ NR activity exhibited similar biphasic kinetics for nitrate. The recombinant NR encoded by the narB gene of Synechococcus sp. strain RF-1, expressed in E. coli, also showed the biphasic kinetics with similar pH and temperature profiles. By in-gel NR activity assay, the recombinant NarB was found to exist as a single form. Both the high- and low-affinity NR activities of the recombinant NarB showed the same thermostability. When modified at the N terminus by a polyhistidine tag, the recombinant NR activity was shifted from biphasic to hyperbolic kinetics and showed only a single K(m) for nitrate, indicating the functional importance of the NarB N-terminal structure in NR kinetics.
...
PMID:Monomeric NarB is a dual-affinity nitrate reductase, and its activity is regulated differently from that of nitrate uptake in the unicellular diazotrophic cyanobacterium Synechococcus sp. strain RF-1. 1312 56

A newly isolated denitrifying bacterium, Thauera sp. strain DNT-1, grew on toluene as the sole carbon and energy source under both aerobic and anaerobic conditions. When this strain was cultivated under oxygen-limiting conditions with nitrate, first toluene was degraded as oxygen was consumed, while later toluene was degraded as nitrate was reduced. Biochemical observations indicated that initial degradation of toluene occurred through a dioxygenase-mediated pathway and the benzylsuccinate pathway under aerobic and denitrifying conditions, respectively. Homologous genes for toluene dioxygenase (tod) and benzylsuccinate synthase (bss), which are the key enzymes in aerobic and anaerobic toluene degradation, respectively, were cloned from genomic DNA of strain DNT-1. The results of Northern blot analyses and real-time quantitative reverse transcriptase PCR suggested that transcription of both sets of genes was induced by toluene. In addition, the tod genes were induced under aerobic conditions, whereas the bss genes were induced under both aerobic and anaerobic conditions. On the basis of these results, it is concluded that strain DNT-1 modulates the expression of two different initial pathways of toluene degradation according to the availability of oxygen in the environment.
...
PMID:Aerobic and anaerobic toluene degradation by a newly isolated denitrifying bacterium, Thauera sp. strain DNT-1. 1500 57

The activated sludge process relies on the formation of strong microbial flocs. The knowledge about dominant floc-forming bacteria is at present very limited, especially from a phylogenetic perspective. In this study, numerous microcolonies in the activated sludge flocs were found to be targeted by a Betaproteobacteria-group-specific oligonucleotide probe using fluorescence in situ hybridization (FISH). Some of these were micromanipulated and further identified by reverse transcriptase polymerase chain reaction (RT-PCR) and sequencing to belong to the Aquaspirillum genus in the Neisseriaceae family. A specific oligonucleotide probe, Aqs997, was designed to target the identified bacteria. A survey in nine different wastewater treatment plants with nutrient removal (WWTP) showed a high abundance of bacteria hybridizing to the oligonucleotide probe developed. Microautoradiography (MAR) combined with FISH on activated sludge incubated with radiolabelled substrate showed uptake of substrate with oxygen, nitrate and nitrite as electron acceptor demonstrating a denitrifying potential of the bacteria investigated. The Aquaspirillum-related bacteria seemed to be abundant denitrifiers in WWTPs with nitrogen removal and they were particularly numerous in plants mainly receiving domestic wastewater, where they constituted up to 30% of all bacteria.
...
PMID:Micromanipulation and further identification of FISH-labelled microcolonies of a dominant denitrifying bacterium in activated sludge. 1504 20


<< Previous 1 2 3 4 Next >>

---