For local treatment of ulcerative colitis, a new azoreductase driven prodrug CDDO-AZO from bardoxolone methyl (CDDO-Me) and 5-aminosalicylate (5-ASA) was designed, synthesized and biologically evaluated. It is proposed that orally administrated CDDO-AZO is stable before reaching the colon, while it can also be triggered by the presence of azoreductase in the colon to fragment into CDDO-Me and 5-ASA, generating potent anti-colitis effects. Superior to olsalazine (OLS, a clinically used drug for ulcerative colitis) and CDDO-Me plus 5-ASA, CDDO-AZO significantly attenuated inflammatory colitis symptoms in DSS-induced chronic colitis mice, which suggested that CDDO-AZO may be a promising anti-ulcerative colitis agent.
Animals ; Colitis/drug therapy* ; Mesalamine/pharmacology* ; Mice ; Nitroreductases ; Oleanolic Acid/pharmacology* ; Prodrugs

Bacterial Proteins ; Humans ; Metronidazole/pharmacology* ; Mycobacterium tuberculosis ; NAD ; Nitroreductases ; Tuberculosis, Lymph Node

Gut bacterial nitroreductases play an important role in reduction of various nitroaromatic compounds to the corresponding N-nitroso compounds, hydroxylamines or aromatic amines, most of which are carcinogenic and mutagenic agents. Inhibition of gut nitroreductases has been recognized as an attractive approach for reducing mutagen metabolites in the colon, so as to prevent colon diseases. In this study, the inhibitory effects of 55 herbal medicines against Escherichia coli(E. coli) nitroreductase (EcNfsA) were examined. Compared with other herbal extracts, Syzygium aromaticum extract showed superior inhibitory potency toward EcNfsA mediated nitrofurazone reduction. Then, the inhibitory effects of 22 major constituents in Syzygium aromaticum against EcNfsA were evaluted. Compared with other tested natural compounds, ellagic acid, corilagin, betulinic acid, oleanic acid, ursolic acid, urolithin M5 and isorhamnetin were found with strong to moderate inhibitory effect against EcNfsA, with IC₅₀ values ranging from 0.67 to 28.98 mol·L^-1. Furthermore, the inhibition kinetic analysis and docking simulation demonstrated that ellagic acid and betulinic acid potently inhibited EcNfsA (K_i < 2 μmol·L ^-1) in a competitively inhibitory manner, which created strong interactions with the catalytic triad of EcNfsA. In summary, our findings provide new scientific basis for explaining the anti-mutagenic activity of Syzygium aromaticum, where some newly identified EcNfsA inhibitors can be used for developing novel agents to reduce the toxicity induced by bacterial nitroreductase.
Ellagic Acid/pharmacology* ; Escherichia coli ; Kinetics ; Nitroreductases/pharmacology* ; Plant Extracts/pharmacology* ; Syzygium

<p>OBJECTIVETo study the effect of NH4(+)-N/NO3(-)-N ratios in the applied supplementary fertilizer on the growth, nitrogen metabolis related enzymes activity and photosynthetic characteristics of Isatis indigotica.p><p>METHODThe sand culture experiment was conducted, and seedling of I. indigotica was fertilized with the mixed nutrition that containing the Hoagland's macro elements and the Aron's micro elements, the additional 63 mmol N was supplementary with the NH4(+)-N/NO3(-)-N ratio of 100:0, 75:25, 50:50, 25:75 and 0:100.p><p>RESULTThe biomass of I. indigotica increased at first when the supplementary N of NH4(+)-N/NO3(-)-N ratio changed from 100:0 to 50:50 and decreased afterwards. The maximum value was at 50:50 and the minimum at 100: 0. With increasing the ratio of NO3(-)-N, the activity of nitrate reductase and glutamine synthetase increased and then decreased and the relationship between the activity and the ratio could be described with an approximate parabola curve. The net photosynthetic rate of I. indigotica was the highest at the NH4(+)-N/NO3(-)-N ratio of 75:25 and the lowest at 100:0.p><p>CONCLUSIONIncreasing the NO3(-)-N ratio properly was beneficial to promote the growth and improve the activity of nitrate reductase and glutamine synthetase and net photosynthetic rate of I. indigotica.p>
Biomass ; Fertilizers ; analysis ; Isatis ; chemistry ; enzymology ; growth & development ; metabolism ; Nitrate Reductase ; metabolism ; Nitrate Reductases ; metabolism ; Nitrates ; analysis ; metabolism ; Nitrogen ; analysis ; metabolism ; Photosynthesis ; Plant Proteins ; metabolism ; Quaternary Ammonium Compounds ; analysis ; metabolism

<p>OBJECTIVETo demonstrate the correlation of rdxA gene mutation and metronidazole (MTZ) resistance of H.pylori isolates in the local area.p><p>METHODSClinical strains of H.pylori were isolated from gastric biopsy of patients. Resistance to metronidazole of the isolates was determined by using diffusion test and two fold dilution test. Genome DNAs of the isolates were prepared for PCR to detect rdxA gene. The target amplification products were sequenced after T-A cloning. The sequences were compared with the reported sequences from Hp26695 and 134 other strains of H.pylori.p><p>RESULTSMTZ resistance rate was 76.1% in 21 clinical isolates. The target fragment 886 bp in length containing rdxA gene could be successfully amplified. In comparison with the reported corresponding sequence of H.pylori stain 26695, homologies of the nucleotide sequences from the amplification products were 90.1% approximate, equals 95.1%. Mutations caused by base insertion/deletion and substitution in the MTZ resistance isolates were found. Among these mutations, two types of insertion mutations have not been reported in literatures. No same mutations were present in the MTZ sensitive isolates.p><p>CONCLUSIONThe rdxA gene mutation may play an important role in MTZ resistance of H.pylori.p>
Amino Acid Sequence ; Drug Resistance, Bacterial ; Helicobacter pylori ; drug effects ; genetics ; Metronidazole ; pharmacology ; Molecular Sequence Data ; Mutation ; Nitroreductases ; chemistry ; genetics

With the rapid development of socialization and industrialization, more and more pollutes were produced and discharged into natural environment. It is harmful to human health and life. These pollutes included refractory degradation organic compounds like PAHs, RDX, HMX, CL-20, PCBs and alkanes and their relative substances. Various compounds exist in nature with long life span. They are the most hazardous than other organics. The impact of pollutes can be treated by microorganisms. Results showed that it is an effective way for bioremediation of these pollutes with microbial metabolism or cometabolism. A few key enzymes, mainly oxidative and reductive enzymes, connected with the first step of initial degradation. Normally, enzymes grouped with other active fraction on the cell membrane are composed of one oxidative and reductive system for substrates oxidation. The metabolic intermediates can be used with TCA by microorganisms. The pathways of metabolism and the key enzymes were summarized. The further research topics should be focused on microorganism screen and its relative enzyme, pathway and mechanism of metabolism or cometabolism for such compounds degradation, and the result was hoped for the environmental protection.
Bacteria ; enzymology ; metabolism ; Biodegradation, Environmental ; Environmental Pollutants ; metabolism ; Nitroreductases ; metabolism ; Organic Chemicals ; isolation & purification ; metabolism ; Oxidation-Reduction ; Oxidoreductases ; metabolism ; Polychlorinated Biphenyls ; metabolism ; Polycyclic Aromatic Hydrocarbons ; metabolism

OBJECTIVE: The aim of this study was to measure circulating levels of nitric oxide metabolites (nitrites) in the uteroplacental, fetoplacental, and peripheral circulation in women with normal pregnancy and preeclampsia. METHODS: Two groups of pregnant women were included : 20 patients with preeclampsia and 18 normotensive women. At cesarean, blood samples were taken from the antecubital vein and uterine vein draining the placental site before delivery of the baby, and the umbilical vein after delivery of the baby. Plasma nitric oxide concentrations were determined with the Griess reaction by measuring combined oxidation products of nitric oxide, plasma nitrite and nitrate after reduction with nitrate reductase. RESULTS: Significantly higher serum nitrite concentrations were found in umbilical (46.53+/-22.01 vs. 17.51+/-7.43 M/L, p<0.05), uterine (51.78+/-14.19 vs. 21.23+/-11.6 M/L, p<0.05) and antecubital (66.41+/-20.87 vs. 21.26+/-9.54 M/L, p<0.05) venous plasma in the preeclamptic group compared with the control group. CONCLUSION: We observe higher levels of nitirc oxide metabolites in the uteroplacental, fetoplacental, and peripheral circulation in women with preeclampsia than in normal pregnancy. These results support the hypothesis that increased nitric oxide production may be a compensatory response to improve blood flow and offset the pathologic effects of preeclampsia.
Female ; Humans ; Nitrate Reductase ; Nitric Oxide* ; Plasma* ; Pre-Eclampsia* ; Pregnancy ; Pregnant Women ; Umbilical Veins ; Veins

OBJECTIVE: This study is directed to determine whether the concentrations of nitrate and nitrite, metabolites of nitric oxide, in vaginal secretions could be used to predict a premature delivery. METHOD: A total of 60 pregnant women from March, 2000 to February, 2001 received continuous prenatal care and underwent delivery in our hospital was enrolled in the study. Gestational age was ranged between 20 and 37 weeks. Those patients were divided into four groups according to clinical parameters such as preterm labor, premature rupture of membranes and premature delivery. Specimens were obtained by thorough washing of vagina with 5 mL sterile physiologic sodium chloride solution for determination of nitric oxide metabolites. The total nitrate and nitrite concentration was determined by treatment with nitrate reductase followed by the Griess reaction. RESULTS: Subjects were divide into four groups (group I, no preterm labor and term delivery[n=19]; group II, preterm labor and term delivery[n=12]; group III, preterm labor and consequent premature delivery[n=6]; Group IV, preterm labor with premature rupture of membranes and consequent premature delivery[n=23]). Total nitrate and nitrite concentrations in group II-IV (62.2+/-50.3micromol/L in group II, 113.3+/-77.0micromol/L in group III, 101.9+/-72.4micromol/L in group IV) were significantly higher than the concentration in Group I (9.4+/-11.9micromol/L). From the receiver operating characteristic curve in the prediction of premature delivery, we set 27.6micromol/L as a cut-off value in this study. Sensitivity, specificity, positive predictive value, and negative predictive value were 71.9%, 78.6%, 79.3%, and 71.0%, respectively. CONCLUSION: Patients with premature delivery do have increased nitric oxide metabolites in vaginal secretions. These results suggest that nitric oxide may be involved in the initiation of cervical ripening and used as a predictor of premature delivery.
Cervical Ripening ; Female ; Gestational Age ; Humans ; Membranes ; Nitrate Reductase ; Nitric Oxide ; Obstetric Labor, Premature ; Pregnancy ; Pregnant Women ; Prenatal Care ; ROC Curve ; Rupture ; Sensitivity and Specificity ; Sodium Chloride ; Vagina

<p>OBJECTIVETo establish a rapid, inexpensive, and simple drug susceptibility test (DST) for Mycobacterium tuberculosis (M. tb) and evaluate its feasibility.p><p>METHODWe used nitrate reductase combined with mycobacteriophage assay (PhaB-NRA) to test 49 clinical M. tb isolates of, and the results were compared with those of PhaB-NRA and traditional absolute concentration method.p><p>RESULTSThe sensitivity, specificity, and accuracy of PhaB-NRA for rifampicin were 89.1%, 91.67%, and 89.8%; on the contrary, those of isonicotinyl hydrazide were 86.21%, 90.0%, and 87.8%, respectively. The coincidence between PhaB-NRA and traditional assay were 0.746 for rifampicin and 0.750 for isonicotinyl hydrazide.p><p>CONCLUSIONSPhaB-NRA is an inexpensive, rapid, and simple DST method. It is a promising rapid screening technique for DST of M. tb.p>
Anti-Bacterial Agents ; pharmacology ; Biological Assay ; methods ; Humans ; Microbial Sensitivity Tests ; methods ; Mycobacteriophages ; physiology ; Mycobacterium tuberculosis ; drug effects ; Nitrate Reductase ; metabolism ; Rifampin ; pharmacology ; Sensitivity and Specificity

<p>OBJECTIVETo establish a rapid method for testing drug sussceptibility on Mycobacterium tuberculosis.p><p>METHODSTaking absolute Concentration method for drug susceptibility testing of M. tuberculosis as the "gold standard", we examined the drug-resistant of M. tuberculosis strain with nitrate reducrase assay (NRA) and the drug-resistant of M. tuberculosis germ in sputum with NRA.p><p>RESULTSNRA and absolute concentration method was basically comparable with NRA susceptibility as 96.5% and the specificity was 100%, When comparing with traditional absolute concentration method, NRA could shorten the time about 3 weeks. Using NRA to test the drug-resistant of M. tuberculosis germ in sputum, its susceptibility was more than 66.7% and specificity was 100%, within 10-20 days.p><p>CONCLUSIONNRA could be used as a rapid drug susceptibility testing on M. tuberculosis.p>
Anti-Bacterial Agents ; pharmacology ; Drug Resistance, Bacterial ; Enzyme Assays ; methods ; Humans ; Microbial Sensitivity Tests ; methods ; Mycobacterium tuberculosis ; drug effects ; pathogenicity ; Nitrate Reductase ; metabolism ; Sputum ; microbiology