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PubMed1974

Determination of the absolute number of Escherichia coli membrane vesicles that catalyze active transport.

Transport of vinylglycolate (2-hydroxy-3-butenoic acid) via the lactate transport system is the limiting step for covalent labeling of membrane vesicles prepared from E. coli ML 308-225. Thus, the rate and extent of vinylglycolate labeling is stimulated about 10-fold by ascorbate-phenazine methosulfate, and stimulation is abolished by 2,4-dinitrophenol and by phospholipase treatment, neither of which affect the rate of vinylglycolate oxidation. [(3)H]Vinylglycolate of high specific activity has been prepared, and vesicles have been labeled with this compound in the presence of ascorbate-phenazine methosulfate. Examination of these preparations by high resolution radioautography in the electron microscope demonstrates that virtually all of the vesicles are labeled. The experiments provide a strong indication that most, if not all, of the membrane vesicles in these preparations catalyze active transport.

Ascorbic Acid↗
PubMed1976

Isolation of pigmentation mutants of Pseudomonas phenazinium.

Pigmentation mutants of Pseudomonas phenazinium unable to synthesize iodinin, or producing it only in reduced amounts, were isolated. The abilities of the mutants to synthesize nine other phenazines were also altered. Cross-feeding experiments and the altered patterns of pigment production suggested metabolic relationships between the phenazine pigments, and a scheme for their biosynthesis is proposed.

Methylnitronitrosoguanidine↗
PubMed1978

Reduction of methemoglobin by cobaltocytochrome c catalyzed by mediators.

The reduction of methemoglobin by cobaltocytochrome c (Cocyt c) has been measured using nine mediators of different half-reduction potentials, Em, 7. The rate increases with the increase of Em, 7 for the mediator but dropped precipitously when it becomes more positive than the Em, 7 for the methemoglobin/hemoglobin couple. The reaction is most efficient with phenzaine methosulfate, therefore it was studied in detail. The reaction is first order in the concentrations of Cocyt c and phenazine methosulfate. The average second-order rate constant for Cocyt c + phenazine methosulfate (M) k1 leads to Cocyt c+ M-. is 2.9 x 10(4) M-1 s-1 at 25 degrees C, 0.1 M phosphate pH 7.0. There is a slight negative temperature dependence of k1 at low temperature; at higher temperatures the process has deltaH not equal to approximately 27 kJ mol-1 and deltaS not equal to approxmately - 75 J mol-1 K-1. The effect of anions reflects the dependence of Em, 7 for the methemoglobin/hemoglobin couple with various anions. There is no significant effect on k1 by the addition of inositol hexakisphosphate. The variation of k1 with pH is complicated. The experimental rate constants are compared with values calculated with the theory of nonadiabatic multiphonon process of electron tunneling.

Azides↗
PubMed1986

Purification and structural analysis of pyocyanin and 1-hydroxyphenazine.

Pyocyanin and related members of the phenazine family are produced by Pseudomonas aeruginosa and have been associated with events of pathophysiological importance. Pyocyanin and its base hydrolysis product 1-hydroxyphenazine were purified to homogeneity by reverse-phase high-pressure liquid chromatography. Their mass spectrometric behaviour was examined with a view to evaluating the use of high-resolution chromatography/mass spectrometry in studying phenazine-mediated effects in man. The molecular mass of naturally derived pyocyanin was determined as 210 Da by thermospray liquid chromatography/mass spectrometry and confirmed by desorption electron-impact mass spectrometry. Mass spectrometric data could not be obtained by fast-atom bombardment or desorption chemical ionisation, techniques commonly used to determine molecular mass of polar or thermally labile species. The thermal lability of underivatised pyocyanin precluded analysis by gas chromatography/mass spectrometry. In contrast to pyocyanin, mass spectrometric data were readily obtained for 1-hydroxyphenazine, using direct probe analysis as well as with gas and liquid chromatography inlet systems.

Chromatography, Gas↗
PubMed1989

Synthesis and characterization of 1-substituted 5-alkylphenazine derivatives carrying functional groups.

The following 1-substituted derivatives of 5-methylphenazine and 5-ethylphenazine were synthesized: 1-(3-carboxypropyloxy)-5-methylphenazine (1B), 1-(3-carboxypropyloxy)-5-ethylphenazine (2B), 1-(3-ethoxycarbonylpropyloxy)-5-ethylphenazine (2C) and 1-[N-(2-aminoethyl)carbamoylpropyloxy]-5-ethylphenazine (2D); their spectra, stability and reactivity as electron mediators were investigated, together with those of 5-methylphenazine (1A) and 5-ethylphenazine (2A). The 1-substituted derivatives are all insensitive to light and the derivatives of 5-ethylphenazine are more stable than those of 5-methylphenazine under neutral and alkaline conditions; 2B is the most stable of all the derivatives. The spectral properties of the decomposed compounds showed that photodecomposition of 1A and 2A is associated with hydroxylation at position 1, alkali decomposition of 1A and 1B with elimination of the 5-methyl group and alkali decomposition of 2A, 2B, and 2D with a ring-opening reaction. The second-order rate constant k1 for the reaction of the phenazine derivatives with NADH was measured under steady-state conditions. The k1 values vary depending on the substituents at positions 1 and 5: the values for 1A, 1B, 2A, 2B, 2C and 2D are 1.83 mM-1 s-1, 3.33 mM-1 s-1, 0.75 mM-1 s-1, 1.42 mM-1 s-1, 1.68 mM-1 s-1 and 2.03 mM-1 s-1, respectively. The rate constants, k2 and k3, for the reactions of the reduced form of 2B with oxygen and with 3-(4',5'-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium ion, respectively, were k2 = 1.21 mM-1 s-1 and k3 = 91 mM-1 s-1. These phenazine derivatives have potential applications in the biochemical field.

Alkylation↗
PubMed1966

Cytochemical localization of lactate dehydrogenase in muscular dystrophy of the mouse.

By use of phenazine methosulfate and the "ncubation mixture film method," lactate dehydrogenase activity has been demonstrated in the dystrophic muscle fibers of strain 129 mice. The results indicate that for demonstration of lactate dehydrogenase activity in dystrophic muscle fibers phenazine methosulfate is necessary. This finding is typical for the "white" muscle fibers in the normal muscle and suggests that the dystrophy affects primarily the "white" muscle fibers.

Animals↗
PubMed1991

Relative importance of fluorescent siderophores and other factors in biological control of Gaeumannomyces graminis var. tritici by Pseudomonas fluorescens 2-79 and M4-80R.

Pseudomonas fluorescens 2-79 suppresses take-all, a major root disease of wheat caused by Gaeumannomyces graminis var. tritici. The bacteria produce an antibiotic, phenazine-1-carboxylic acid (PCA), and a fluorescent pyoverdin siderophore. Previous studies have established that PCA has an important role in the biological control of take-all but that antibiotic production does not account fully for the suppressiveness of the strain. To define the role of the pyoverdin siderophore more precisely, mutants deficient in production of the antibiotic, the siderophore, or both factors were constructed and compared with the parental strain for control of take-all on wheat roots. In all cases, strains that produced PCA were more suppressive than those that did not, and pyoverdin-deficient mutant derivatives controlled take-all as effectively as their respective fluorescent parental strains. Thus, the phenazine antibiotic was the dominant factor in disease suppression and the fluorescent siderophore had little or no role. The siderophore also was of minor importance in a second strain, P. fluorescens M4-80R, that does not produce PCA. Strains 2-79 and M4-80R both produced substances distinct from the pyoverdin siderophore that were responsible for fungal inhibition in vitro under iron limitation, but these substances also had, at most, a minor role in disease suppression in situ.

Antifungal Agents↗
PubMed1986

Effect of ciliostatic factors from Pseudomonas aeruginosa on rabbit respiratory cilia.

Heat-stable factors released by Pseudomonas aeruginosa in culture supernatants inhibit functional cilia of rabbit tracheal epithelium. Chloroform extraction removed heat-stable factors from stationary-phase culture supernatants. The extracts contained at least seven components separable by thin-layer chromatography (TLC). Cilioinhibitory components were identified as a phenazine derivative, pyo compounds (2-alkyl-4-hydroxyquinolines), and a rhamnolipid, also known as a hemolysin. Fluorescence and absorption spectra, relative migration on TLC, staining characteristics, and gas chromatography were the basis for identification. Inhibitory concentrations of each active component were established by quantitative measures of percent motility and beat frequency. Corresponding damage to ciliary ultrastructure was examined by electron microscopy. The pyo compounds produced ciliostasis at concentrations of 50 micrograms/ml, but without obvious ultrastructural lesions. The phenazine derivative also inhibited ciliary motility and caused some membrane disruption, although at substantially greater concentrations of 400 micrograms/ml. Limited exposure of tracheal explants to the rhamnolipid resulted in ciliostasis which was associated with altered ciliary membranes. More extensive exposure to rhamnolipid was associated with removal of dynein arms from axonemes. Pyocyanin at a concentration of 0.5 mg/ml did not inhibit ciliary beating under our conditions. The data suggest that the pyo compounds are the most effective per weight ciliostatic factors released by P. aeruginosa and rhamnolipid is the most destructive of cilia ultrastructure. By interfering with normal ciliary function, these ciliostatic factors may enable P. aeruginosa to more easily colonize the respiratory tract.

Animals↗
PubMed1972

Role of iron and sulfur in pigment and slime formation by Pseudomonas aeruginosa.

Media and an analytical scheme have been developed which allow both a qualitative and quantitative estimation of the formation of pyocyanine, related phenazines, pyorubrin, and a blue and a yellow-green fluorescent pigment by Pseudomonas aeruginosa. Use of the defined pyocyanine medium of Frank and DeMoss with sulfate or various organic sulfur sources allowed formation of pyocyanine, related phenazines, and pyorubrin. When sulfite was the sulfur source with or without iron, P. aeruginosa formed either a yellow-green or a blue fluorescent pigment. Formation of fluorescent pigments of P. aeruginosa is related to the ability of sulfite to act as a specific sulfur source. In an investigation of the role of both added iron and sulfur sources, complex patterns of pigment formation were observed. In addition to the fluorescent pigments, sulfite also supported the formation of slime by P. aeruginosa.

Culture Media↗
PubMed2006

Detection of antibiotic-related genes from bacterial biocontrol agents with polymerase chain reaction.

Pseudomonas chlororaphis PA23, Pseudomonas spp. strain DF41, and Bacillus amyloliquefaciens BS6 consistently inhibit infection of canola petals by Sclerotinia sclerotiorum in both greenhouse and field experiments. Bacillus thuringiensis BS8, Bacillus cereus L, and Bacillus mycoides S have shown significant inhibition against S. sclerotiorum on plate assays. The presence of antibiotic biosynthetic or self-resistance genes in these strains was investigated with polymerase chain reaction and, in one case, Southern blotting. Thirty primers were used to amplify (i) antibiotic biosythetic genes encoding phenazine-1-carboxylic acid, 2,4-diacetylphloroglucinol, pyoluteorin, and pyrrolnitrin, and (ii) the zwittermicin A self-resistance gene. Our findings revealed that the fungal antagonist P. chlororaphis PA23 contains biosynthetic genes for phenazine-1-carboxylic acid and pyrrolnitrin. Moreover, production of these compounds was confirmed by high performance liquid chromatography. Pseudomonas spp. DF41 and B. amyloliquefaciens BS6 do not appear to harbour genes for any of the antibiotics tested. Bacillus thuringiensis BS8, B. cereus L, and B. mycoides S contain the zwittermicin A self-resistance gene. This is the first report of zmaR in B. mycoides.

Antibiosis↗
PubMed1990

The influence of structural modifications of dihydrophenazines on arachidonic acid mobilization and superoxide generation by human neutrophils.

In this study the effects of nine dihydrophenazine derivatives, relative to clofazimine (B663), on the N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) stimulated release of superoxide anion and on the spontaneous generation of arachidonic acid by human neutrophils were investigated. Previous findings that the pro-oxidative activity of the agents depended largely on the substitution in position 2 of the phenazine molecule and on chlorination in the paraposition of the phenyl and anilino rings were confirmed. Only riminophenazines, but not aposafranone derivatives or the imidazophenazine B621, could enhance superoxide release from activated neutrophils. The lack of chlorination of the phenyl and anilino rings could be compensated for by chlorine substitution in position 7 of the phenazine core. The priming effect of the agents on FMLP stimulated superoxide generation was completely prevented by the phospholipase A2 inhibitor 4-p-bromophenacyl bromide. Furthermore pro-oxidative activities correlated closely with a stimulatory effect of the agents on arachidonic acid release. It was therefore concluded that dihydrophenazine derivatives with pro-oxidative properties can prime neutrophils for FMLP-stimulated superoxide release by modulation of phospholipase A2 activity.

Arachidonic Acid↗
PubMed2000

Fatty acids enhanced tubermycin production by Pseudomonas strain 2HS.

A new microbial isolate, Pseudomonas 2HS, produced trace amounts of a greenish-yellow pigment when grown aerobically in a 1% yeast extract medium at 30 degrees C and shaken at 250 rpm for 5 days. In contrast, cells produced more greenish-yellow pigment (2.16 mg/15 ml culture) when grown in the presence of 0.5% 12-hydroxyoctadecanoic acid (w/v). The greenish-yellow pigment was identified as phenazine-1-carboxylic acid (tubermycin B), and the Pseudomonas 2HS was identified as P. aeruginosa 2HS. This is the first report that 12-hydroxyoctadecanoic, ricinoleic and other fatty acids can enhance the production of phenazine-1-carboxylic acid by a Pseudomonas species.

Animals↗
PubMed1998

[Studies on control of root rot on Panax notoginseng].

Chemical Control tests of pot, plot and field for Panax notoginseng root rot were conducted during 1995-1996. The results indicated that the chemical control is a effect measure to control rapidly occurring and spreading of Panax notoginseng root rot. It was the best treatment to coordinate use of bactericide and fungicide, obviously better than alone or mixed use of fungicide and also better than alone use of bactericide. In the pot and plot tests, the best coordinate treatment was the treatment of 10% phenazine plus 70% dexon plus 50% bavistin and plus water (1:1:500), the control effect was 70%; in the field test, the control effect of over 70% was also get with the treatment of 10% phenazine plus 70% dexon and plus small soil (1 Kg:1 Kg:150 Kg) per mu.

Benzenesulfonates↗
PubMed1987

Steady-state kinetic analysis for the reaction of ammonium and alkylammonium ions with methylamine dehydrogenase from bacterium W3A1.

The steady-state kinetic mechanism for the reaction of n-alkylamines and phenazine ethosulfate (PES) or phenazine methosulfate (PMS) with methylamine dehydrogenase from bacterium W3A1 is found to be of the ping-pong type. This conclusion is based on the observations that 1/v versus 1/[methylamine] or 1/[butylamine] plots, at various constant concentrations of an oxidizing substrate, and 1/v versus 1/[PES] or 1/[PMS] plots, at various constant concentrations of a reducing substrate, are parallel. Additionally, the values of kcat/Km for four n-alkylamines are identical when PES is the oxidizing substrate, as were the kcat/Km values for four reoxidizing substrates when methylamine was the reducing substrate. Last, analysis of steady-state kinetic data obtained when methylamine and propylamine are presented to the enzyme simultaneously and PES and PMS are used simultaneously also supports the involvement of a ping-pong mechanism. The enzymic reaction with either methylamine or PES is dependent on the ionic strength, and the data indicate that each interacts with an anionic site on methylamine dehydrogenase. The presence of ammonium ion at low concentration activates the enzyme, but at high concentration this ion is a competitive inhibitor in the reaction involving methylamine and the enzyme. A complete steady-state mechanism describing these ammonia effects is presented and is discussed in light of the nature of the pyrroloquinoline quinone cofactor covalently bound to the enzyme.

Amines↗
PubMed1975

[Sensitivity of m. kansasii strains to various antibiotics and chemotherapeutics in vitro and in vivo (author's transl)].

Sensitivity of 40 strains of M. kansasii (var. luciflava) to various antibiotics and chemotherapeutics in vitro and in vivo was examined. The strains showed considerable individual variability in their susceptibility in vitro, most were more resistant to isoniazid and PAS and about one half of the investigated strains to streptomycin, too, if correlated to "wild" strains of M. tuberculosis. Susceptibility to ethionamide, thiosemicarbazone (Conteben), viomycin, kanamycin and cycloserine appears to be the same as in the case of M. tuberculosis strains, but the resistance to pyrazinamide is higher. Good effect has been observed in vitro with rifampicin, ethambutol, capreomycin and phenazine derivative B 663. Oleandomycin and gentamycin are ineffectual in the dosages of drugs we used. The activity of most of these drugs was observed in experimental infections of white mice--in mono-therapy and in various combinations-provoked by different strains of M. kansasii. The main criterion of the effectivity of the treatment was the enumeration of viable mycobacterial units in the lungs of the mice in ten-days intervals; in one part of the experiments the histological examination of the various organs of the mice was performed. The drugs of the I. and II. line of antituberculotics were ineffective or showed only a slight effect. A very good effect of rifampicin, ethambutol and phenazine derivative B 663 in monotherapy and in multiply drug therapy was observed.

Animals↗
PubMed1979

Formate dehydrogenase mutants of Salmonella typhimurium: a new medium for their isolation and new mutant classes.

We have designed a new medium for the differentiation of mutants of Salmonella typhimurium defective in the ability to reduce nitrate with formate, and have characterized 24 formate dehydrogenase (FDH) mutants isolated on this medium. The mutants were assayed for the ability to use formate to reduce benzyl viologen and phenazine methosulfate, and were mapped by means of conjugation and P22-mediated transduction. Mutants lacking the ability to reduce either dye were found to map at three distinct sites: at a site co-transducible with xyl (presumably fdhA), at a site or sites between 13U and 33U, but not co-transducible with aroA, bio, purB, pyrC, or pyrD (near, but not identical with fdhB), and at asite 10-20% co-transducible with pyrE, for which we suggest the designation fdhC. Six mutant isolates reduced benzyl viologen, but not phenazine methosulfate. They retained the ability to produce nitrite during growth with nitrate. They mapped between 83U and 89U, but no co-transduction was found with metE, glnA, metB, or argH. The combined biochemical and genetic data suggest the existence of a gene in this area which is essential for the reduction of nitrate with formate, but not for formate hydrogenlyase activity or for nitrate reductase activity.

Aldehyde Oxidoreductases↗
PubMed1975

Reduction of oxidized inorganic nitrogen compounds by a new strain of Thiobacillus denitrificans.

Denitrification by Thiobacillus denitrificans "RT" strain was investigated using manometry and gas chromatography. 1. From nitrate, resting cells produced only nitrogen anaerobically with thiosulfate as the electron donor. The data suggest that nitrate was assimilated and dissimilated by the same nitrate reductase, assayed with benzyl-viologen as the electron donor. 2. From nitrite, whole cells produced nitric oxide, nitrous oxide and nitrogen, using thiosulfate as the electron donor; nitrogen was the final product of the reduction. Crude extract reduced nitrite to nitrogen with p-phenylene-diamine and dimethyl-p-phenylene diamine as the electron donors, and produced nitric oxide, nitrous oxide and nitrogen with tetramethyl-p-phenylene-diamine as the electron donor. Nitrite was reduced to nitric oxide and nitrous oxide by crude extract using ascorbate-phenazine methosulfate as the electron donor. 3. From nitric oxide, whole cells produced nitrous oxide and nitrogen using thiosulfate as the electron donor, nitrogen was the final reduction product. Nitric oxide was reduced to nitrous oxide by crude extract with the ascorbate-phenazine methosulfate system. 4. Whole cells reduced nitrous oxide to nitrogen with thiosulfate as the electron donor. It was not possible to detect any nitrous oxide reductase activity in crude extract. 5. A scheme was of denitrification by Thiobacillus denitrificans "RT" strain.

Aerobiosis↗
PubMed1979

(1-14C) acetate assimilation by obligate methylotrophs, Pseudomonas methanica and Methylosinus trichosporium.

The oxidation of one carbon compounds (methane, methanol, formaldehyde, formate) and primary alcohols (ethanol, propanol, butanol) supported the assimilation of [1-14C]acetate by cell suspensions of type I obligate methylotroph, Pseudomonas methanica, Texas strain, and type II obligate methylotroph, Methylosinus trichosporium, strain PG. The amount of oxygen consumed and substrate oxidized correlated with the amount of [1-14C]acetate assimilated during oxidation of C-1 compounds and primary alcohols. Oxidation of methanol, formaldehyde, and primary alcohols in extracts of Pseudomonas methanica, Texas strain, and Methylosinus trichosporium, strain PG, was catalyzed by a phenazine methosulfate linked, ammonium ion dependent methanol dehydrogenase. The oxidation of aldehydes was catalyzed by a phenazine methosulfate linked, ammonium ion independent aldehyde dehydrogenase. Formate was oxidized by a NAD+ linked formate dehydrogenase.

Acetates↗