WS-9659 A and B, novel testosterone 5 alpha-reductase inhibitors isolated from a Streptomyces. I. Taxonomy, fermentation, isolation, physico-chemical characteristics

WS-9659 A and B, produced by Streptomyces sp. No. 9659, were extracted from cultured broth, purified by solvent extraction followed by chromatography on silica gel and then isolated as prisms (C22H24N2O, mp 161 approximately 162 degrees C, C22H23N2OCl, mp 152 approximately 153 degrees C). WS-9659 A and B have testosterone 5 alpha-reductase inhibitory activity. The IC50 values of WS-9659 A and B for partially purified rat prostate testosterone 5 alpha-reductase were 5.0 x 10(-7) M and 1.0 x 10(-5) M, respectively.

[The physiologic role of pyocyanine synthesized by Pseudomonas aeruginosa]

The physiological role of pyocyanine for Pseudomonas aeruginosa was studied. Its synthesis was shown to commence at the retardation growth phase. Pyocyanine was accumulated only in the growth medium. The addition of 2,6-dichlorophenolindophenol accepting the reducing equivalents from coenzyme Q and transferring them to cytochrome c inhibited the pigment accumulation. This was indicative of the connection between pyocyanine synthesis and the level of the reducing equivalents in the cells. Pyocyanine did not accept the reducing equivalents from coenzyme Q in the respiratory chain of P. aeruginosa. Only reduced pyridine nucleotides served as substrates for pyocyanine in the reaction of autooxidation. The kinetic parameters of this reaction and the affinity of NADH dehydrogenase for the substrate were measured. The kinetic data were analysed to show that, under the physiological conditions, pyocyanine could not apparently compete with the respiratory chain for the reducing equivalents and hence directly regulate the level of NAD(P)H in P. aeruginosa cells. In order to keep the oxidising activity at a level necessary for the cells, the latter decreased the content of the reducing equivalents either by synthesizing pyocyanine or owing to the activity of cyanide-resistant oxidase. These processes of releasing the reducing equivalents are in a reciprocal relationship.

Role of a phenazine antibiotic from Pseudomonas fluorescens in biological control of Gaeumannomyces graminis var. tritici

Pseudomonas fluorescens 2-79 (NRRL B-15132) and its rifampin-resistant derivative 2-79RN10 are suppressive to take-all, a major root disease of wheat caused by Gaeumannomyces graminis var. tritici. Strain 2-79 produces the antibiotic phenazine-1-carboxylate, which is active in vitro against G. graminis var. tritici and other fungal root pathogens. Mutants defective in phenazine synthesis (Phz-) were generated by Tn5 insertion and then compared with the parental strain to determine the importance of the antibiotic in take-all suppression on wheat roots. Six independent, prototrophic Phz- mutants were noninhibitory to G. graminis var. tritici in vitro and provided significantly less control of take-all than strain 2-79 on wheat seedlings. Antibiotic synthesis, fungal inhibition in vitro, and suppression of take-all on wheat were coordinately restored in two mutants complemented with cloned DNA from a 2-79 genomic library. These mutants contained Tn5 insertions in adjacent EcoRI fragments in the 2-79 genome, and the restriction maps of the region flanking the insertions and the complementary DNA were colinear. These results indicate that sequences required for phenazine production were present in the cloned DNA and support the importance of the phenazine antibiotic in disease suppression in the rhizosphere.

Revised structure for the phenazine antibiotic from Pseudomonas fluorescens 2-79 (NRRL B-15132)

A phenazine antibiotic (mp, 243 to 244 degrees C), isolated in a yield of 134 micrograms/ml from cultures of Pseudomonas fluorescens 2-79 (NRRL B-15132), was indistinguishable in all of its measured physicochemical (melting point, UV and infrared spectra, and gas chromatography-mass spectrometry data) and biological properties from synthetic phenazine-1-carboxylic acid. Gurusiddaiah et al. (S. Gurusiddaiah, D. M. Weller, A. Sarkar, and R. J. Cook, Antimicrob. Agents Chemother. 29:488-495, 1986) attributed a dimeric phenazine structure to an antibiotic with demonstrably similar properties obtained from the same bacterial strain. Direct comparison of the physicochemical properties of the authentic antibiotic obtained from D. M. Weller with synthetic phenazine-1-carboxylic acid and with the natural product from the present study established that all three samples were indistinguishable within the experimental error of each method. No evidence to support the existence of a biologically active dimeric species was obtained. Phenazine-1-carboxylic acid has a pKa of 4.24 +/- 0.01 (25 degrees C; I = 0.09), and its carboxylate anion shows no detectable antimicrobial activity compared with the active uncharged carboxylic acid species. These data suggest that phenazine-1-carboxylic acid is probably not an effective biological control agent for phytopathogens in environments with a pH greater than 7.

DC-86-M, a novel antitumor antibiotic. I. Taxonomy of producing organism and fermentation

A novel antibiotic, DC-86-M was isolated from the culture broth of a new isolate, DO-86, from the soil sample collected in Machida-shi, Japan. The producing organism was found to belong to Streptomycetes, for it formed aerial mycelia and chains of spores and its cell wall analyses revealed the presence of LL-diaminopimelic acid. The morphological, cultural and physiological characteristics of the strain DO-86 resemble closely those of Streptomyces luteogriseus and we concluded that the strain DO-86 could be designated as Streptomyces luteogriseus DO-86. The antibiotic was produced in the fermentation medium consisting of lactose 20 g, glucose 10 g, Pharmamedia 15 g, yeast extract 5 g, meat extract 10 g and CaCO3 2 g per liter of tap water.

Differential primary plating medium for enhancement of pigment production by Pseudomonas aeruginosa

A cost-effective and more rapid means of detection of Pseudomonas aeruginosa in cultures from clinical specimens would be very advantageous. We have developed a modified MacConkey agar (MMA), which enhances pigment production of P. aeruginosa and which, if pyocyanin pigment is present, provides a relatively rapid and very cost-effective identification. The MMA medium inhibits the gram-positive organisms, while lactose- and non-lactose-fermenting gram-negative rods are easily distinguishable from pigment-producing pseudomonads. Organisms that produce pyocyanin, pyoverdin, or pyorubin, or both pyocyanin and pyoverdin, are easily recognized on the medium. Pyocyanin production is clearly distinguishable from other Pseudomonas pigments on MMA. In a comparative study, MMA identified 97% of the P. aeruginosa strains 24 h earlier than routine laboratory biochemical methods. Highly mucoid strains which did not produce detectable pigments on standard biochemicals produced detectable pigments on the MMA within 48 h. This medium can provide a very practical, reliable, and cost-effective means for early characterization of P. aeruginosa.

Identification of Pseudomonas aeruginosa by pyocyanin production on Tech agar

Pseudomonas aeruginosa is the only gram-negative bacillus capable of producing the very distinctive water-soluble pigment pyocyanin. We evaluated the reliability of this characteristic as a unique test for the identification of this organism by using Tech agar (BBL Microbiology Systems, Cockeysville, Md.) medium. A retrospective and prospective analysis was performed with a total of 835 strains of P. aeruginosa; 818 (98%) produced pigment within 48 h of incubation, and 96% of those which produced pigment were positive after overnight incubation. Seventeen strains (2.0%) failed to produce pigment; 15 were mucoid strains from patients with cystic fibrosis. Tech agar is an effective, simple, and inexpensive medium for P. aeruginosa identification and may be used as a unique test for all potential P. aeruginosa isolates (beta hemolytic on blood agar; lactose-negative, oxidase-positive colonies). Nonpigmented mucoid strains, as well as other nonpigmented organisms, will require additional testing to ensure proper identification.

4,9-Dihydroxyphenazine-1,6-dicarboxylic acid dimethylester and the 'missing link' in phenazine biosynthesis

4,9-Dihydroxyphenazine-1,6-dicarboxylic acid dimethylester, the ester form of a proposed 'missing link' in the biosynthesis of phenazines, has been isolated from a strain of Pseudomonas cepacia.

Pyocyanine production by Pseudomonas aeruginosa

Dextrose enhanced the growth of P. aeruginosa but suppressed the biosynthesis of pyocyanine. The preformed pigment could be released from dead cells. Pigmentation was not correlated directly with number of viable organisms in the culture. High concentration of maltose likewise inhibited pyocyanine production. Maltose contained in medium used for pyocyanine production by P. aeruginosa should be kept in low concentration or omitted.

Incorporation of [14C]shikimate into plenazines and their further metabolism by Pseudomonas phenazinium

1. During growth of Pseudomonas phenazinium on l-threonine medium, phenazine pigment formation commenced early and 1,6-dihydroxyphenazine 5,10-dioxide (iodinin) was the major component. Growth on l-[U-(14)C]threonine showed that when growth was complete about 25% of the label had been incorporated into phenazines and 30% into cell substance. 2. The addition of d-[2,3,4,5(n)-(14)C]shikimate to cultures at different phases of growth showed that the greatest efficiency of incorporation (about 70%) occurred in the mid- to late-exponential phase. Phenazines accounting for most of the (14)C supplied were iodinin and 9-hydroxyphenazine-1-carboxylate plus 2,9-dihydroxyphenazine-1-carboxylate. Radioactivity incorporated into cell substance was about one-third of the amount found in phenazines. 3. Kinetic studies showed that radioactivity from a pulse of [(14)C]-shikimate was incorporated into phenazines immediately, without a discernible lag, and into all detectable phenazines simultaneously rather than sequentially. 4. Radioactive phenazines isolated from culture media were fed to growing cultures and their metabolism was studied. The results supported a scheme for the biosynthesis of iodinin and 1,8-dihydroxyphenazine 10-monoxide by a branched pathway. 5. It is proposed that phenazine-1,6-dicarboxylate is the common precursor of all naturally occurring phenazines.

The branchpoint of pyocyanine biosynthesis

Mutant strains of Pseudomonas aeruginosa, blocked in the pathway of aromatic amino acid biosynthesis, were isolated to determine the branchpoint of pyocyanine biosynthesis. Studies of the enzyme complement of these mutants and determination of pyocyanine production indicated that chorismic acid is an intermediate in the pathway and is the branchpoint compound.

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.

Chromogenesis variations in strains of Pseudomonas aeruginosa growing in presence of chloramphenicol and oxytetracycline

The effects of subinhibitory doses of chloramphenicol and oxytetracycline on chromogen formation by normal and antibiotic-resistant Pseudomonas aeruginosa strains were studied. Partial or total inhibitions of the phenazine compounds were observed while the oxyphenoxazone synthesis appeared increased. In addition, several molecular modifications, presumably as a physiological response against the damaging drugs, were detected.

Characterization of Pseudomonas species isolated from clinical specimens

More than 90 morphological and physiological characters of 227 strains of pseudomonads isolated from clinical specimens and 16 reference strains are described. The clinical isolates included P. aeruginosa (apyocyanogenic), P. fluorescens, P. putida, P. pseudomallei, P. cepacia, P. acidovorans, P. alcaligenes, P. pseudoalcaligenes, P. stutzeri, P. putrefaciens, P. maltophilia, and P. diminuta.

Regulation of aromatic amino acid biosynthesis in phenazine-producing strains of Pseudomonas

Regulation of 3-deoxy-d-arabino-heptulosonate-7-phosphate (DAHP) synthetase was studied in eight strains of Pseudomonas which synthesize phenazine compounds. Repression studies with individual aromatic amino acids led to the finding that enzyme synthesis was repressed in only one strain, P. aureofaciens B1543p, and by only one amino acid, l-tyrosine. Feedback inhibition by the aromatic amino acids varied from strain to strain in terms of the type of inhibitory control, and the particular acid or acids which inhibited. Prephenate and chorismate, as well as a number of naturally occurring phenazine compounds, inhibited the DAHP synthetase activity to varying degrees.

Pyocyanine degradation by apyocyanogenic strains of Pseudomonas aeruginosa

Six apyocyanogenic strains of Pseudomonas aeruginosa were shown to be capable of degrading pyocyanine under conditions normally conducive to pigment formation. P. aeruginosa B-275 was shown to metabolize pyocyanine to the extent that it was no longer chloroform extractable by following the fate of 14C-labeled pyocyanine. Also, P. aeruginosa B-275, an apyocyanogenic strain, was found capable of producing pyocyanine by the dilution of radioactivity in undegraded 14C-labeled pigment.

A simple diagnostic milk medium for Pseudomonas aeruginosa

An agar medium containing 10% defatted milk has been tested as a diagnostic medium for Pseudomonas aeruginosa and, in particular, for differentiating between P. aeruginosa and P. fluorescens. Only P. aeruginosa colonies gave clear zones due to hydrolysis of casein together with diffused green pigment. Results on milk agar correlated well with the pattern of results from a variety of conventional tests used to identify this organism. Pigment production of P. aeruginosa on milk agar was better than on special media commonly used to enhance this characteristic. Routine diagnosis of P. aeruginosa is recommended by streaking on a solid medium containing 10% defatted milk granules, 25% nutrient broth, and 2% agar, and examining for clear zones and pigment after 24 hours' incubation.

Simultaneous production of three phenazine pigments by Pseudomonas aeruginosa Mac 436

Pseudomonas aeruginosa Mac 436 was found to produce simultaneously three phenazine pigments identified as pyocyanine, phenazine-1-carboxylic acid, and oxychlororaphine. Production of these pigments on various media indicated a wide variation in yields depending on the composition of the media, but satisfactory yields of all three pigments were obtained. A scheme was developed for separation and assay of the pigments from the culture liquor. Details of production, isolation, assay, and identification are given.

Simultaneous biosynthesis of pyocyanine, phenazine-1-carboxylic acid, and oxychloroaphine from labelled substrates by Pseudomonas aeruginosa Mac 436

Pyocyanine, phenazine-1-carboxylic acid, and oxychlororaphine are produced simultaneously by Pseudomonas aeruginosa Mac 436 in certain media. When 14C-labelled substrates were supplied, the labelled carbon was incorporated into each of the pigments in varying amounts and also into CO2 and cells. Incorporation of labelled carbon from glycerol-1,3-14C and glycerol-2-14C was better than from shikimic-1,6-14C acid, and much better than from glucose-1-14C, -2-14C, or -6-14C, succinic-1,4-14C or -2,3-14C acid, or acetic-1-14C or -2-14C acid. The data suggest that all three pigments are synthesized through the same route although some variations in the results are difficult to explain. The conclusion is that the shikimic acid pathway is the probable route of synthesis.