Pigment production by Cryptococcus neoformans from para- and ortho-Diphenols: effect of the nitrogen source

Cryptococcus neoformans produced pigments when p-diphenols were substrates in a glucose-amino acid-salts medium. The best substrates were 2.5-dihydroxybenzoic acid and 2,5-dihydroxybenzenesulfonic acid. In contrast to the cellular pigment production from o-diphenols (hydroxyl groups in the 2,3- or 3,4-position of phenyl ring), the p-diphenols (1,4- or 2,5-positions for the hydroxyl groups) produced large amounts of soluble pigments that diffused into the medium. When an optimal source of nitrogen (glutamine, glycine, and asparagine) was used, 89% of the C. neoformans strains produced pigments from p-diphenols. In contrast, 0 to 67% of the strains produced pigments when a suboptimal nitrogen source (proline, ammonium sulfate, ornithine, and methionine) was used. When glutamine-glycine-asparagine was the nitrogen source, 100% of the C. neoformans strains produced pigments from o0diphenols, whereas 77 to 100% of the strains produced pigment when proline-ammonium sulfate-ornithine-methionine was the nitrogen source. Cryptococcus species other than C. neoformans and all tested Candida species failed to produce pigments from any of the substrates except when hydroquinone was used. A combination of glutamine-glycine-asparagine and 3,4-dihydroxyphenylalanine allowed differentiation of colonies of C. neoformans from C. albicans in 3 to 6 days. These data showed that pigment production from o- and p-diphenols served as an excellent biochemical test for the identification of C. neoformans.

The tiron free radical as a sensitive indicator of chloroplastic photoautoxidation

Wheat chloroplasts photochemically reduced molecular oxygen, as a Hill oxidant in the Mehler reaction, to superoxide anion which then oxidized added 1,2-dihydroxybenzene-3,5-disulfonate to its semiquinone, a comparatively stable free radical at pH 7. The last mentioned reaction was rapid in aqueous solution, but the rate of formation of 1,2-dihydroxybenzene-3,5-disulfonate semiquinone by the chloroplast system was calculated as T1 of 0.6 s. The Mehler reaction, or more specifically the univalent reduction of oxygen by Photosystem I, was rate-limiting so that the 1,2-dihydroxybenzene-3,5-disulfonate seniquinone was a useful spin probe for superoxide anion production at room temperature. The ESR signal of 1,2-dihydroxybenzene-3,5-disulfonate semiquinone was proportional to its steady state concentration and decayed in the dark with a T1/2 of 5-6 s. This oxygen-dependent signal was enhanced by mediation of chloroplastic oxygen reduction through methyl viologen. The superoxide anion scavengers ascorbate and L-epinephrine competitively obscured 1,2-dihydroxybenzene-3,5-disulfonate semiquinone formation, butadded superoxide dismutase was not as effective in this role. Partial inhibition by superoxide dismutase was achieved only by preincubation of Photosystem I enriched particles with ten times the endogenous concentration of superoxide dismutase. This and the persistence of a small amount of a 1,2-dihydroxybenzene-3,5-disulfonate (Tiron) oxidizing species in the dark supports the concept of Tiron accessibility but not the superoxide dismutase accessibility of superoxide anion bound in its formative enzyme complex. Benzoquinone and naphthoquinone disulfonate also reacted with superoxide anion, and supported both the Hill reaction and the Mehler reaction as final oxidants of both water and superoxide anion.

Bacterial metabolism of arylsulfonates: role of meta cleavage in benzene sulfonate oxidation by Pseudomonas testosteroni

Pseudomonas testosteroni H-8 oxidizes certain lower alkylbenzene sulfonates at rates inversely related to the length of the alkyl group. Appreciable Q(O)2 values were observed for benzene sulfonate (BS), toluene sulfonate (TS), and ethylbenzene sulfonate (EBS), but not for propylbenzene sulfonate (PS) and higher homologues. Catechol oxidation was catalyzed by a constitutive catechol-2,3-oxygenase (EC 1.99.2.a). Yellow meta cleavage products accumulated when BS-grown cells were exposed to catechol, 4-methylcatechol, 3-methylcatechol, EBS and PS, but not BS or TS. Traces of a yellow metabolite (probably 2-hydroxymuconic semialdehyde) were detectable during growth on BS. PS completely inhibited growth on BS, but not on L-leucine or nutrient broth. Also, PS antagonized respiration on BS and catechol, but not glutamate, the extent of inhibition being directly related to PS concentration. Formation of a meta cleavage product from PS, and inhibition of catechol oxidation by PS, suggested that the actual inhibitor may not be PS itself, but a metabolite.

Agar plate method for detection and enumeration of alkylbenzenesulfonate-degrading microorganisms

A simple method for detection and enumeration of alkylbenzenesulfonate (ABS)-degrading microorganisms by using agar plates was developed and used in microbiological studies of coastal marine and polluted river waters. The method depends upon the color responses of neutral red in alkaline medium. Neutral red changes from pink, when it enters into ABS micelles, to yellow, when the ABS is degraded, and does not form micelles. When neutral red-tris(hydroxymethyl)-aminomethane buffer solution and then cationic surfactant solution were sprayed onto the agar surface of ABS-nutrient agar cultures, transparent haloes appeared around the colonies of ABS-degrading microorganisms against a pink background. Viable counts of ABS-degrading bacteria isolated from both seawater and freshwater environments were considerably higher in polluted waters than in less polluted areas. Viable counts of ABS-degrading bacteria averaged 1.5 x 105/ml in samples from the surface water of polluted Tokyo Bay and 3.0 x 104/ml in samples from the surface water of polluted Tamagawa River but were fewer in number in samples from less polluted waters.

[Microflora of active ooze participating in the decomposition of sulfanilic acid]

Microflora of domestic water can be a source of active ooze adapted to sulphanilic acid. Adaptation of the microflora to sulphanilic acid at a concentration of 170-200 mg/l takes 6 to 8 days. The microflora of active ooze, immediately after adaptation, consists mainly of Pseudomonas species, Ps. denitrificans, Ps. fluorescens, Ps. striata, Ps. putida, etc., and also of Achromobacter stutzeri, Achromobacter flavum, Mycobacterium phlei, Mycobacterium mucosum, Bacillus mesentericus, Bac. cereus, saccharomyces cerevisiae, Schizosaccharomyces pombe, and Rhodotorula glutinus. The number of the species decreased as a result of long cultivation of active ooze on a minimal medium with sulphanilic acid as a sole source of carbon and nitrogen; the following strains prevailed: Ps. putida, Ps. eisenbergii, strains of Mycobacterium phlei and Flavobacterium solare. The isolated strains of Ps. putida and Ps. eisenbergii decomposed sulphanilic acid by 60.0--79.5 percent, and together with Mycobacterium phlei by 100 percent during 4 to 7 days. The ability to oxidize sulphanilic acid decreased after storage. Addition to the medium of other sources of carbon, nitrogen and vitamins did not restore the lost ability of the microorganisms to decompose sulphanilic acid.

Microbial degradation of alkylbenzenesulphonates. Metabolism of homologues of short alkyl-chain length by an Alcaligenes sp

1. An organism isolated from sewage and identified as an Alcaligenes sp. utilized benzenesulphonate, toluene-p-sulphonate or phenylethane-p-sulphonate as sole source of carbon and energy for growth. Higher alkylbenzenesulphonate homologues and the hydrocarbons, benzene, toluene, phenylethane and 1-phenyldodecane were not utilized. 2. 2-Phenylpropanesulphonate was metabolized to 4-isopropylcatechol. 3. 1-Phenylpropanesulphonate was metabolized to an ortho-diol, which was tentatively identified, in the absence of an authentic specimen, as 4-n-propylcatechol. 4. In the presence of 4-isopropylcatechol, which inhibited catechol 2,3-dioxygenase, 4-ethylcatechol accumulated in cultures growing on phenylethane-p-sulphonate. 5. Authentic samples of catechol, 3-methylcatechol, 4-methylcatechol, 4-ethylcatechol and 3-isopropylcatechol were oxidized by heat-treated extracts to the corresponding 2-hydroxyalkylmuconic semialdehydes. Ring cleavage occurred between C-2 and C-3. 6. The catechol derived from 1-phenylpropanesulphonate was oxygenated by catechol 2,3-dioxygenase to a compound with all the properties of a 2-hydroxyalkylmuconic semialdehyde, but it was not rigorously identified. 7. The catechol 2,3-dioxygenase induced by growth on benzenesulphonate, toluene-p-sulphonate or phenylethane-p-sulphonate showed a constant ratio of specific activities with catechol, 3-methylcatechol, 4-methylcatechol and 4-ethylcatechol that was independent of the growth substrate. At 60 degrees C, activity towards these substrates declined at an identical first-order rate. 8. Enzymes of the ;ortho' pathway of catechol metabolism were present in small amounts in cells grown on benzenesulphonate, toluene-p-sulphonate or phenylethane-p-sulphonate. 9. The catechol 1,2-dioxygenase oxidized the alkylcatechols, but the rates and the total extents of oxidation were less than for catechol itself. The oxidation products of these alkylcatechols were not further metabolized.