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PubMed1979

[The mechanism of the tetrazolium reduction and the effect of phenazinmethosulfate (author's transl)].

Modern results of the literature form the basis for the presentation of a scheme which shows the reduction of tetrazolium salts and the action of phenazine methosulfate under histochemical conditions. The reduction of tetrazolium salts passes the radical state and it hapens principally on the niveau of the flavin proteins and the ubiquinone. The importance of the superoxide radical for the reduction of tetrazolium salts under aerobic conditions is emphasized.

Aerobiosis↗
PubMed1979

Kinetic studies of the blood serum xanthine dehydrogenase inhibition by alloxan (2,4,5,6-tetraoxypyrimidine 5,6-dioxyuracil).

Alloxan is an inhibitor of the enzyme xanthine: NAD+ oxido reductase (E.C.1.2.1.37). Alloxan acts as an electron acceptor and competes "in vitro" with the tetrazolium salt used as electron acceptor in the assay system used for the determination of the dehydrogenase activity of the enzyme. The alloxan inhibition was reverted when phenazine methosulfate (PMS) was added to the system.

Alloxan↗
PubMed1990

[Antitumor effect of a novel antitumor compound, NC-190, in the double grafted tumor system].

The antitumor effect of NC-190, N-beta-dimethylaminoethyl-9-carboxy-5-hydroxy-10-methoxybenzo [alpha] phenazine-6-carboxamide sodium salt, with a new experimental mouse model was studied. Intratumoral administration of NC-190 strongly inhibited the growth of Meth-A solid tumors in male BALB/c mice and led to a complete tumor regression and also resistance to the reinoculated tumor. Subsequently, the anti-metastatic effect of NC-190 was examined in the double grafted tumor system, in which mice first received simultaneous intradermal inoculations of Meth-A in both right (10(6) cells) and left (2 X 10(5) cells) flanks and were then injected with 25 micrograms of NC-190 in the right tumor on days 3, 4 and 5. NC-190 inhibited the growth of not only the right but also the left, non-treated tumor. Immunized spleen cells were taken from mice which had been cured by the intratumoral administration of NC-190. Adoptive transfer of NC-190 immunized spleen cells caused a complete regression of Meth-A tumors. The effector cell activity was lost only after treatment with anti-Lyt-2 antibody. These results suggest that intratumoral administration of NC-190 might induce Lyt-2 positive cytotoxic cells in the spleen and the left, non-treated tumor. In BALB/c nude mice, NC-190 inhibited slightly the growth of the right tumor but did not that of the left tumor. Therefore, the antitumor activity of NC-190 in the double grafted tumor system was judged as associated with a sequential immune mechanism in which T cells may play an important role. TILs (tumor infiltrating lymphocytes) obtained from the left and right sides tumors treated with NC-190 were examined by Winn assay for their antitumor activity against Meth-A sarcoma in BALB/c mice. TILs obtained from neither sides inhibited the growth of admixed Meth-A cells. Different from immunopotentiators such PSK or IL-1, NC-190 enhanced neither concomitant immunity nor sinecomitant immunity.

Animals↗
PubMed1987

The role of oxygen radicals in dye-mediated photodynamic effects in Escherichia coli B.

Photosensitive dyes representative of the thiazines, xanthenes, acridines, and phenazines mediated phototoxicity in Escherichia coli B. The observed phototoxicity was sensitizer-, light-, and oxygen-dependent and is therefore a photodynamic effect. Hydroxyl radical scavengers conferred protection against the photodynamic action of all of the representative dyes. The extent of protection was dependent on the concentration of scavenger and on the in vitro reactivity of the scavenger with the hydroxyl radical. Exogenous superoxide dismutase and catalase partially protected the cells against the dye-mediated phototoxicity, and prior induction of intracellular superoxide dismutase and catalase by growth in glucose minimal medium containing manganese and paraquat substantially protected E. coli B against the photodynamic action of all of the dyes examined. Combinations of protective treatments against the phototoxicity of all four classes of dyes, including superoxide dismutase and catalase preinduction and addition of extracellular superoxide dismutase and catalase or the addition of hydroxyl radical scavengers, provided nearly complete protection against the oxygen-dependent component of dye-mediated lethality. E. coli B grown in glucose minimal medium containing manganese and photosensitive dyes induced manganese superoxide dismutase. The extent of induction was correlated with the dyes' ability to photooxidize NADH in vitro. Thus, oxygen radicals are primarily responsible for the oxygen-dependent toxicity of the photosensitive dyes examined, and one adaptive response of E. coli B to a dye-mediated oxidative threat is to induce superoxide dismutase.

Acridines↗
PubMed1966

Oxidation of 7-dehydrocholesterol by a mouse liver microsomal system dependent on reduced pyridine nucleotides.

Aerobic incubation of 7-dehydrocholesterol with mouse liver microsomes in the presence of a detergent, an iron salt, and NADH or NADPH resulted in the conversion of the sterol to more polar products. In the presence of Fe(3+) or low levels of Fe(2+) the reaction was dependent upon reduced pyridine nucleotide and a microsomal enzyme system. At high levels of Fe(2+) or in the presence of Fe(2+) or Fe(3+) and ascorbic acid, nonenzymatic oxidation of 7-dehydrocholesterol occurred in the absence of NADH or NADPH. Chromatograms of products resulting from the enzyme-dependent and enzyme-independent reactions were similar. The enzymatic reaction was inhibited by certain chelating agents, by antioxidants, and by menadione, phenazine methosulfate, and ferricyanide. Low concentrations of EDTA stimulated the reaction and high concentrations inhibited it. In the complete system sterol oxidation was correlated with the peroxidation of microsomal lipids, but peroxidation of microsomal lipids proceeded more rapidly when either the sterol, the detergent, or both were omitted. Ergosterol was resistant to oxidation under conditions that caused extensive loss of 7-dehydrocholesterol. Microsomes from tissues other than liver were relatively inactive.

Animals↗
PubMedDate not supplied

[A method of determining catalase and superoxide dismutase in erythrocytes using an open-type analyzer].

Human erythrocyte catalase activity was studied involving the peroxidase reaction with ethanol and the reverse alcohol dehydrogenase reaction. The adequate kinetic parameters of the reaction were obtained under mild conditions of hemolysate preparation. Estimation of catalase activity in series of hemolysates enabled us to measure the activity values near 220.0 kU/ml of erythrocytes which corresponded to those in literature. Adaptation of the superoxide dismutase activity evaluation in erythrocytes was carried out using the basic system NADH-phenazine methasulfate-tetrazolium blue and the analyzer FP-901 equipped for nine simultaneous measurements. The rate of base reactions was plotted and the linear correlation was found between the reaction inhibition per cent and content of erythrocyte hemolysate and of commercially available preparation of superoxide dismutase. The procedures are simple and reproducible and may be used in routine studies of antioxidants.

Alcohol Dehydrogenase↗
PubMedDate not supplied

[Suppression of influenza virus NP-protein mRNA translation in vitro with derivatives of an antisense oligonucleotide].

Inhibition of the influenza virus protein NP mRNA with derivatives of an antisense oligonucleotide complementary to the 5' terminus of the mRNA was investigated. The derivatives were prepared by conjugation of aromatic 2-chloroethylamine, cholesterol, porphyrin, and phenazine groups to the 5'-terminal phosphate of the oligonucleotide. The most efficient inhibitors were found to be the conjugates bearing the alkylating, cholesterol and phenaznium groups.

Base Sequence↗
PubMed1998

Safranine-O as membrane potential probe: a mechanistic study using fluorescence spectroscopy.

Use of safranine-o has been examined as membrane potential probe in 1-palmitoyl-2-oleoyl-3-phosphatidylcholine (POPC) vesicles both in presence and absence of cholesterol. The fluorescence signal increases in presence of vesicles and the increase in fluorescence intensity on hyperpolarization with valinomycin is diffusion potential dependent. The fluorescence spectra recorded after time driven experiments reveals the blue shift in gamma max of fluorescence with increasing diffusion potential. The fluorescence spectra of vesicles-associated dye is at variance with those of the safranine-o in organic solvents. In organic solvents with increasing hydrophobic character of the solvent the gamma max is slightly red shifted. The electronic spectra of the dye molecule and the charges on different atomic centers have been calculated by quantum chemical method GRINDOL. The predicted first excited state originating from the phenazine moiety is in very good agreement with the excitation wavelength. On the basis of charges on various atoms the binding of safranine with vesicles has been discussed. The nonlinear behaviour of fluorescence signal with delta phi, anisotropy measurements and the computational results, reveal the penetration of bound dye molecules (along with orientation) as a function of diffusion potential. Addition of microaliquots of 1.5 M K2SO4 to already hyperpolarized vesicles decreases the fluorescence signal and the fluorescence spectra recorded on stabilization of signal after each addition showed a shift in gamma max of fluorescence in opposite direction i.e. red shifted.

Cholesterol↗
PubMed1998

[Chemotherapeutic agents under study].

The development of new drugs with strong antituberculous activity and fewer side effects which are not cross-resistant to conventional antituberculosis drugs is urgently desired now. The chemotherapeutic agents under study which are considered a candidate for a new antituberculosis drug are listed below. 1) Rifamycin derivatives: rifabutin, rifapentin, KRM-1648, FCE-22250, 22807, CGP-7040, 27557, 29035, 29861, P-DEA, SPA-S-565, R-76-1. 2) New quinolones: ofloxacin, ciprofloxacin, levofloxacin, sparfloxacin, gatifloxacin, CS-940, Du-6859a. 3) Phenazines: clofazimine, B746, B4101, B4154, B4157. 4) Pyrazinamide derivatives: N-hydroxy pyrazinamide, N-hydroxy pyrazinamide-4-oxide. 5) Nitroimidazole derivatives: metronidazole et al.

Anti-Infective Agents↗
PubMedDate not supplied

Preliminary investigations of an amperometric oligosaccharide dehydrogenase-based electrode for the detection of glucose and some other low molecular weight saccharides.

Biosensors for the determination of sugars were constructed using oligosaccharide dehydrogenase (ODH) and soluble phenazine methosulfate (PMS) or an osmium-based three-dimensional redox hydrogel. In the latter case the enzyme and poly(1-vinylimidazole) complexed with osmium (4,4'-dimethylbpy)2Cl were cross-linked with poly(ethylene glycol) diglycidyl ether. Both electrode configurations showed similar sensitivities for glucose in the range between 8 and 21 muAmM-1 cm-2. The responses for 10 mono and oligosaccharides were studied. There was no response for fructose. In the concentration range 0.1-20 mM the relative sensitivities were determined for arabinose (96%), xylose (3%), mannose (50%), galactose (11%), glucose (100%), maltose (24%), lactose (12%), cellobiose (34%) and maltotriose (10%).

Biosensing Techniques↗
PubMed1999

Visualization of the enzyme trimethylamine oxide demethylase in isoelectric focusing gels by an enzyme-specific staining method.

An enzyme-specific staining method for trimethylamine oxide demethylase (TMAO-ase) was developed. Direct visualization could be reached by coupling the reactions of the specific TMAO-ase assay with another reaction step generating as final product a dark-blue formazan. For these purposes 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) as tetrazolium salt and phenazine methosulfate (PMS) as electron transfer substance were used. Clear, dark-blue colored bands could be detected on 300 microm isoelectric focusing gels (IEF). Comparisons of enzyme-stained and protein-stained gels showed that diffusion could not be observed and that the band pattern of TMAO-ase could also be seen in the protein stain. The pI range where TMAO-ase was located was 5.6-6.6 for extracts and 6.2-6.6 for partially purified TMAO-ase. Specificity of stained TMAO-ase bands was assessed by the preparation of staining solution without the substrate trimethylamine oxide (TMAO) and by extraction of TMAO-ase from the gel and performance of the specific TMAO-ase assay.

Aldehyde-Lyases↗
PubMed2002

Activity staining of glutathione peroxidase after electrophoresis on native and sodium dodecyl sulfate polyacrylamide gels.

Glutathione peroxidase (GSH-Px), from commercial bovine erythrocytes or ammonium sulfate fractionations (30-45%, 45-60%, 60-75% and 75-90% saturations) of ginger rhizome, was detected on polyacrylamide gels after native polyacrylamide gel electrophoresis (PAGE) or sodium dodecyl sulfate (SDS)-PAGE. The gel was submerged in a 50 mM Tris-HCl buffer (pH 7.9) containing 13 mM glutathione and 0.004% hydrogen peroxide with gentle shaking for 10-20 min. The GSH-Px activity was stained with a solution containing 1.2 mM 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 1.6 mM phenazine methosulfate (PMS) for 10 min. The clear zone of GSH-Px activity on a purple background was found in both native and SDS-PAGE gels. This fast and sensitive method can be used in the process of enzyme purification and characterization of mammalian or plant cells.

Animals↗
PubMed1992

Roles of secondary metabolites from microbes.

The common feature of the seemingly diverse array of biological activities exhibited by microbial secondary metabolites is their survival value for the producing organism. The propensity to form these compounds is unevenly distributed in microbial taxa and seems more closely associated with existence in a competitive environment than with phylogeny. The characteristic multibranched elaboration of secondary biosynthetic pathways and the marked species specificity of the end products are consistent with their evolution by an 'inventive' mechanism. The species specificity suggests that distinctive terminal reactions may be of recent origin. However, comparisons of the nucleotide sequence of genes involved in the biosynthesis of phenazine and polyketide metabolites with related genes of primary pathways indicate that the secondary pathways have not evolved exclusively within the organisms in which they are now found. Sequence similarities with related primary pathway genes in phylogenetically distant organisms suggest that gene transfer has played an important part in the evolution of secondary metabolism. The diversity of products may reflect the many roles for which secondary metabolites have been selected after the genes for their biosynthesis have transferred to organisms with different physiologies and different environment challenges.

Bacteria↗
PubMed1988

Kearns-Sayre syndrome: biochemical studies of mitochondrial metabolism.

Examination of oxidative metabolism in mitochondria isolated from quadriceps skeletal muscle biopsy specimens of 4 patients with Kearns-Sayre syndrome has shown that the mitochondria were tightly coupled, with maximal respiratory rates depending on the presence of adenosine diphosphate (ADP), Ca2+, or uncoupler. The state 3 respiratory rates with nicotinamide adenine dinucleotide (NAD)-linked substrates and succinate were much lower than those of control subjects. The cytochrome oxidase activities (measured with ascorbate + phenazine methosulfate as substrates) were also decreased, but this segment of the respiratory chain was not rate-limiting for succinate or NAD-linked substrate oxidation. Analyses of the steady-state reduction kinetics of the respiratory chain carriers revealed that the rate-limiting step of the impaired respiration with succinate or NAD-linked substrates lies between the c cytochromes and cytochrome oxidase. Measurement of the total substrate-reducible (at anaerobiosis) and chemically reducible levels of the cytochromes in mitochondria from 3 patients showed a severe deficiency of cytochrome a + a3 and an excess of the c cytochromes. To our knowledge, this is the first instance in which a mitochondrial electron transfer defect and cytochrome oxidase deficiency has been shown to be associated with an excess of the c cytochromes.

Adolescent↗
PubMed1996

Scavenging of free radicals by tenoxicam: a participating mechanism in the antirheumatic/antiinflammatory efficacy of the drug.

The radical scavenging activity of tenoxicam against hydroxyl (HO.), superoxide (O2.-), and peroxyl (LOO.) radicals, all of them involved in the inflammatory reactions, has been tested in different cell-free systems and by different techniques. Tenoxicam is a good scavenger of both HO. radicals (IC50 = 56.7 microM), as determined by Electron Spin Resonance (ESR) spectroscopy with the spin trapping (5,5-dimethyl-1-pyrroline N-oxide, DMPO) technique, and O2.- radicals generated by the phenazine methosulfate/reduced beta-nicotinamide adenine dinucleotide (PMS/NADH) system. The high reactivity of the drug towards HO. was confirmed by the rate constant of reaction with HO. (k approximately 10(10) M-1s-1), determined by competition kinetic studies with N,N-dimethyl-4-nitrosoaniline. In addition at a microM level (1-5 microM) it dose-dependently prevents the phycoerythrin peroxidation induced by the water-soluble azoinitiator 2,2-azobis (2-amidinopropane) dihydrochloride (ABAP), indicating a quenching effect on aqueous peroxyl radicals. The HO.-entrapping capacity was confirmed in models more close to the in vivo situation: tenoxicam inhibits the HO.-induced depolymerization of hyaluronic acid already at 15 microM and the HO.-driven lipid peroxidation in phosphatidylcholine liposomes (PCL) with an IC50 of 10 microM. In this membrane model it delays at 1-10 microM level the decomposition of phosphatidylcholine hydroperoxides to short-chain alkenals (markers: total carbonyl functions as 2,4-dinitrophenylhydrazones and conjugated dienes). The high susceptibility of the drug to HO. attack is also demonstrated by its extensive degradation (HPLC studies) when irradiated with HO. radicals. The antioxidant component of tenoxicam evidenced in this study sheds some light on the hitherto undefined mechanism of the antiinflammatory action of the drug.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1978

Continuous dehydrogenation of a steroid with immobilized microbial cells: effect of an exogenous electron acceptor.

Whole cells of Pseudomonas testosteroni, induced to synthesize steroid-transforming enzymes beforehand, have been immobilized by entrapment in polyacrylamide gel. The immobilized cells have been used to catalyze the continuous delta1-dehydrogenation of Reichstein's substance S under various conditions in the presence of phenazine methosulfate (PMS), an electron acceptor for the cell-free delta1-dehydrogenase. The presence of PMS substantially increases the rate of reaction when fed with the steroid substrate to a continuous stirred tank reactor containing the immobilized cells. The operational half-life of the delta1-dehydrogenase activity of the cells, about 103 hr under the best operating conditions, is essentially unaffected by the presence of PMS. Though the acceleration of the reaction may be due to PMS-mediated passage of electrons from some component in the electron transport chain to molecular oxygen, the lack of a similar effect with methylene blue is consistent with the conclusion that PMS functions directly as the electron acceptor for the delta1-dehydrogenase.

17-Hydroxycorticosteroids↗
PubMed2007

Structural variation from 1D to 3D: effects of ligands and solvents on the construction of lead(II)-organic coordination polymers.

A series of Pb(II) coordination polymers [Pb(ndc)(dpp)] (1), [Pb(ndc)(ptcp)].0.5 H2O (2), [Pb(ndc)(dppz)] (3), [Pb(ndc)(tcpn)(2)] (4), [Pb2(ndc)2(tcpp)] (5), [Pb(Hndc)2].H2O (6), [Pb(ndc)(dma)] (7), [Pb(bdc)(dma)] (8), [Pb(trans-chdc)(H2O)] (9), and [Pb2(cis-chdc)2].NH(CH3)2 (10), where ndc=1,4-naphthalenedicarboxylate, dpp=4,7-diphenyl-1,10-phenanthroline, ptcp=2-phenyl-1H-1,3,7,8-tetraazacyclopenta[l]phenanthrene, dppz=dipyrido[3,2-a:2',3'-c]phenazine, tcpn=2-(1H-1,3,7,8-tetraazacyclopenta[l]phenanthren-2-yl)naphthol, tcpp=4-(1H-1,3,7,8-tetraazacyclopenta[l]phenanthren-2-yl)phenol, dma=N,N-dimethylacetamide, bdc=1,4-benzenedicarboxylate, and chdc=1,4-cyclohexanedicarboxylate, have been synthesized from a hydrothermal or solvothermal reaction system by varying the ligands or the solvents. Compounds 1-5 crystallize with an N-donor chelating ligand and an aromatic dicarboxylate linker. Compounds 1-4 are 1D polymers with different pi-pi stacking interactions, whereas compound 5 consists of 2D layers. The structures of compounds 7, 8, and 10 are 3D frameworks formed by connection of the Pb(II) centers by organic acid ligands. Compound 7 is chiral although the ndc ligand is achiral, while the framework of 8 is a typical 3D (3,4)-connected net. Compound 10 is the first example of Pb(II) wheel cluster [Pb(8)O(8)] units bridged by carboxylate groups. Compound 6 contains 1D chains which are further extended to a 3D structure by pi-pi interactions. Compound 9 consists of a 2D network constructed by Pb(II) centers and trans-chdc ligands. The structural differences between 7 and 8 and between 9 and 10 indicate the importance of solvents for framework formation of the coordination polymers. By varying the solvent the cis and trans conformations of H(2)chdc in 9 and 10 were separated completely. The photoluminescence and nonlinear optical properties of the coordination polymers have also been investigated.

Journal Article↗
PubMed1987

Differential riboflavin deposition in white and variegated white mutants of Drosophila hydei.

Riboflavin deposition in organs of Drosophila hydei was studied by means of a growth test using a riboflavin-deficient strain of the fungus Aspergillus nidulans. In wild-type animals, riboflavin is deposited in Malpighian tubules (MT) and testes but not in adult eyes. Certain white (w) mutants do not contain riboflavin, whereas intermediately colored w mutants contain minor amounts of the substance. Riboflavin-containing MT cells contain special globules that can be fixed and stained with the redox dye phenazine-methosulphate. The number and size of these granules is related to growth effect and point to a role of the w locus in the intracellular deposition of riboflavin in special organs. In white-mottled (wm) position-effect variegation mutants, a significant correlation was found between the extent of variegation (percentage of yellow cells) and riboflavin content (growth effect) of the MT. However, the individual variation of cell phenotype was extremely large and exaggerated types were observed indicating "overdominance" of the rearranged w+ gene. This contradicts an unsubstantiated dogma of position-effect variegation that assumes that the affected gene simply switches between the on and off state, as is discussed.

Animals↗