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An atypical strain of Pseudomonas aeruginosa capable of synthesizing three phenazine pigments was isolated. Cultural conditions, under which the strain forms either chlororaphin, oxychlororaphin, or pyocyanine, are described. This broad spectrum of pigment production, as well as some other characteristics, sets this strain apart from previously described chlororaphin producers.
Of 72 clinical isolates of Pseudomonas aeruginosa examined for simultaneous production of secondary metabolites, 86% produced 2-alkyl-4-hydroxyquinolines, 75% produced rhamnolipids, and 58% produced phenazines, including pyocyanin. Whereas isolates producing two or one constituted smaller groups, 39% released all three metabolites. Metabolite production did not appear to influence site of infection.
The artificial electron-donor system, phenazine methosulfate (PMS) ascorbate, inhibited active transport of glucose by Pseudomonas aeruginosa irrespective of whether the incubation systems were in air, flushed with oxygen, or gassed with nitrogen under anaerobic denitrifying conditions. Active transport of glucose by P. aeruginosa was also inhibited by reduced 5-N-methyl-phenazonium-3-sulfonate, a membrane-impermeable electron donor. PMS-ascorbate caused rapid depletion of intracellular adenosine triphosphate (ATP) when added to respiring cell suspensions of P. aeruginosa either in the presence or absence of glucose or succinate as oxidizable energy sources. In contrast, under identical conditions, Escherichia coli formed ATP with PMS-ascorbate as the sole oxidizable energy source and ATP formation continued when glucose or succinate was present in addition to PMS-ascorbate in the incubation system.
Glucose metabolism was stimulated in isolated perfused rat lungs by perfusion with 2,4-dinitrophenol (DNP), an uncoupler of oxidative phosphorylation or phenazine methosulfate (PMS), an artificial hydrogen acceptor. Lungs were ventilated with 95% O2:5% CO2 and perfused with Krebs-Ringer bicarbonate buffer pH 7.4 containing 5.5 mM [U-14C, 5-3H]glucose for 100 min. In control lungs, 45% of total glucose 14C was recovered as perfusate lactate plus pyruvate (L+P) and 24% as 14CO2. Perfuson with 0.8 mM DNP resulted in a 102% increase in 14CO2 production and a 98% increase in L+P, associated with a fall in tissue ATP/ADP ratio and decreased incorporation of glucose carbons into lipids. Perfusion with 8 muM PMS resulted in a 116% increase in 14CO2 production but no change in L+P; the lactate-to-pyruvate ratio in the perfusate was reduced to 4 from a control value of 10, and tissue adenine nucleotide levels were unchanged. In all experiments, 3H was mainly recovered as 3H2O in the perfusate. These data demonstrate the pattern of response of the isolated lung preparation to uncoupling of oxidative phosphorylation and to alterations in cytoplasmic redox state. The results suggest that the isolated lung preparation is metabolically intact and suitable for study of metabolic control processes.
The activity of lactate dehydrogenase (LDH) in freeze-dried sections of rat testes was determined by using a fluorometric assay method and found to be 4.47 +/- 0.23 moles/Kg dry weight/hr (MKDH +/- S.E.M.) in whole sections, 3.31 +/- 0.16 in tubules and 12.0 +/- 1.9 in interstitial tissue. The activities and regional variation are similar to those measured in nervous tissue and are well correlated with the histochemical localization of LDH activity when phenazine methosulphate (PMS) is not used as an electron carrier. LDH and lipoamide dehydrogenase activity have the same histochemical distribution and there is no nonspecific staining with either method. The use of PMS results in reduced dependence on substrate and coenzyme and does not indicate higher interstitial activity but may provide an indication of developing lactate metabolism in maturing sperm. It is recomended that methods with and without PMS be used in studies of LDH activity in the testis.
The chlorophyll fluorescence of isolated chloroplasts in the presence of phenazine methosulfate (PMS) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) can be quenched in a light-depentdent reaction. This phenomenan has been studied and the following observations were made: 1. Quenching occurs under non-phosphorylating conditions and is stimulated by Mg2+ ions. 2. Under the same conditions, a light-dependent, Mg2+ stimulated transient decrease of absorption at change and binding of PMS. Others, such as methylamine, ammonia, gramicidin and nigericin do not. It is suggested that fluorescence quenching, transient absorption change and binding of PMS are casually related. The concept, postulated by others, that a high-energy state of the chloroplast membrane is involved in the fluorescence lowering is questioned.
A novel, solvent extractable, antibiotic complex has been purified from the fermentation broth of an unusual member of the genus Streptosporangium. Two of the major components were isolated from the complex by alumina column chromatography. One of the components was identified as a previously reported compound, 1,6-dihydroxyphenazine. The other component was a novel chlorine containing phenazine, 1,6-dihydroxy-2-chlorophenazine, which exhibited broad spectrum antifungal activity in vitro against dermatophytes and Candida.
A novel phenazine antitumor antibiotic is described, produced by Streptomyces lomondensis subsp. galanosa NRRL 15738. The antibiotic is selectively active versus the bacterium Streptococcus pneumoniae (MIC less than 0.46 microgram/ml); the antitumor activity versus murine P388 leukemia is T/C 149.
A new, highly substituted phenazine with antitumor activity was isolated from the culture broth of a Streptomyces sp. This compound, whose structure was determined by spectroscopic methods and verified by X-ray diffraction analysis, was found to be methyl 6-formyl-4,7,9-trihydroxy-8-methyl-1-phenazinecarboxylate.
A new phenazine antibiotic, DOB-41, was isolated from the culture broth of a Pseudomonas strain. The antibiotic obtained as yellow crystals showed UV maxima at 255 nm and 370 nm. A molecular formula, C19H18N2O6, was indicated by elemental analysis and mass spectrometry. The structure was elucidated by X-ray diffraction analysis. The antibiotic exhibited inhibitory activity against Gram-positive bacteria, and antitumor effect against leukemia P388 in mice.
Two novel metabolites, SB 212021 and SB 212305, have been isolated from a Streptomyces and shown to have molecular formulae of C15H10N2O5 and C20H17N3O8S, respectively. The structures were deduced by a combination of NMR techniques and mass spectral fragmentation patterns and shown to be novel members of the phenazine group of antibiotics. In the absence of added zinc, both compounds had IC50's of 1-75 microM for the Bacteroides fragilis 262 CfiA and Xanthomonas maltophilia L-1 metallo-beta-lactamases. The compounds also inhibited ACE with IC50's of 55 and 68 microM, respectively. Mode of action studies illustrate that the compounds inhibit some metalloenzymes by chelation of the active site metal ion. They exhibit poor antibacterial activity.
A detailed screening of the secondary metabolite pattern produced by different athropod associated strains of the species Streptomyces anulatus resulted in the isolation and structure elucidation of the endophenazines A-D (2, 4-6). The structures were assigned by spectroscopic methods and chemical transformations. 4 represents a chromophoric system based on a phenazin-7-one, 5 and 6 are new 5,10-dihydrophenazine derivatives.
A reversed-phase HPLC method for the determination of phenazine-1-carboxylic acid (PCA) in antifungal agent M18 is established. The mobile phase was a mixture of MeOH-5 mmol/L phosphate buffer (pH 5.0) (60:40, volume ratio). The flow rate was 1.0 mL/min, and the detection wavelength was 248 nm. The linear range and detectable limit were 50 mg/L-500 mg/L and 30 mg/L respectively. The recovery was 97.53% and RSD was 1.5%. The method of PCA extraction and detection has proven to be much faster, simpler, more sensitive, accurate and reproducible than those reported already. The assay results can be used as a very important criterion for large-scale production.
Detailed investigation of the spatial structure of duplex (Phn-NH(CH2)2NH) x pd(CCAAACA).pd(TGTTTGGC) having a covalently linked N-(2-hydroxyethyl)-phenazine in aqueous solution was continued by means of one- and two-dimensional 1H-NMR spectroscopy. Distances between the protons of the oligonucleotides as well as distances between the phenazinium and the nearest nucleotide groups protons were determined from the series of one-dimensional NOE experiments. The effective correlation time tau c determined for some proton pairs shows the phenazinium fragment to have greater internal motion than the heterocyclic bases. The deoxyribose protons coupling constants show the sugars to be in 2'-endo-conformation. The restrained molecular mechanics have yielded a possible structure of duplex in the aqueous solution fitting the experimental set of interproton distances.
The spatial structure of duplex (Phn-NH(CH2)2NH)pd(CCAAACA).pd(TGTTTGGC) having a N-(2-oxyethyl)-phenazinium residue covalently linked with the 5'-terminal phosphate of the heptanucleotide was studied by means of one- and two-dimensional 1H-NMR spectroscopy. The resonances of phenazinium protons, ethylenediamine linker protons, as well as, oligonucleotide H5/H6/H8/CH3 base protons and H1',H2'a, H2'b, H3', H4' deoxyribose protons have been assigned by means of 1H-COSY, 1H-NOESY and 1H-13C-COSY. The presence of the phenazine residue in duplex causes an additional imino proton signal of the terminal (G-7).(C-1) base pair, suggesting a higher stability of the duplex (Phn-NH(CH2)2NH)pd(CCAAACA).pd(TGTTTGGC) as compared to the unmodified duplex pd(CCAAACA).pd(TGTTTGGC). Analysis of NOE interactions between protons of the dye and the oligonucleotides show the phenazinium polycyclic system to intercalate between G-7 and C-8 residues of the octanucleotide.
Pseudomonas sp. M18 is one of the plant-growth-promoting rhizobacteria, which can produce fungicides: phenazine-1-carboxylic acid (PCA) and pyoluteorin (Plt). The chromosomally gacA inactivated mutant named M18G was constructed and its PCA production was enhanced 31-fold and Plt production was almost blocked completely in KMB medium. To assess the mutual influence of two antibiotics, the plt gene cluster mutant M18T and the phz gene cluster mutant M18GA were then constructed. Non-Plt-producing M18T could synthesize the same amount of PCA as wild type strain. Plt could not be detected in M18GA while PCA production was inhibited dramatically in it. Results indicate that promotion of PCA and inhibition of Plt production in M18G do result from the inactivation of gacA gene. It suggests that the production of antibiotics in strain M18 is differentially mediated by the gacA.
Stability of alkylating derivatives of decathymidylates protected on the 3'-terminal by cholesterol and phenazine residues has been studied in the process of their interaction with cells of Acholeplasma laidlawii PG-8. It is shown that the studied reagents are not split by nucleases of A. laidlawii PG-8 for the time necessary for alkylation of mycoplasma biopolymers.
Photomodification of a 302-membered single-stranded DNA fragment by 5'-mono- and 3',5'-di-N-(2-oxyethyl)phenazine (Phn) derivatives of oligonucleotides has been investigated. Under strong laser irradiation (lambda 532 nm; power density 2,5 GV/cm2, irradiation dose 30 J) the DNA fragment in the presence of Phn-reagents was significantly destructed (up to 70-95%). The level of complementary addressed modification (24-51%) is a direct function of the length of oligonucleotide address of the photoreagent and the amount of Phn residues, stabilizing the complementary complex. The character of the nonaddressed modification is close to the statistic one, although for a number of photoreagents a rather efficient nonspecific modification of 5'-terminal sequence of target DNA has been detected. Of interest also is an unusually broad positional direction of the DNA fragment photomodification in the area of perfect complementary coupling of 5'-Phn-reagents.