• Korean Journal of Microbiology
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• v.28 no.4
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• pp.283-289
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• 1990

The competence time of Streptomyces viridochromogenes for aerial mycelium formation was determined. Within 10 hrs after spore inoculation the submerged mycelium was programed to form aerial mycelium, when the former was laid on agar plate. The white aerial mycelium was formed 17-22 hrs after the transfer. Ascorbic acid oxidizing enzyme band on native gel showed chracteristic mobility change during aerial mycelium formation. Total activity of this enzyme did not show any correlation with the differentiation. The asay condition for the crude enzyme was determined. EDTA and $FeCl_{2}$ showed stimulatory effect. Approximate ratio of oxygen consumed to ascorbic acid oxidized was 1:1.

• Journal of Life Science
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• v.9 no.2
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• pp.1-4
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• 1999

Nonactin, as a radical-producing antibiotic, was isolated from the cultural broth of the strain JM-4151. This strain was identified as Streptomyces viridochromogenes and designated S. viridochromogenes JM-4151. The antibacterial activity of nonactin against Bacillus subtilis was antagonized by the activity opf quercetin, an oxygen radical scavenger. This result suggests that oxygen radical formation might be the cause for the antibacterial activity of nonactin.

• Journal of Microbiology
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• v.34 no.4
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• pp.316-319
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• 1996

Mycelia of Streptomyces viridochromogenes grown under different pH were analysed for the fatty acid composition. The low relative proportion of 12-methyltetradecanoic acid and the high relative proportion of palmitic acid were characteristic for the young culture under slight acidic pH that caused delay of the aerial mycelium formation. The addition of L-arginine to the culture medium enabled an arginine auxotroph with bald phenotype to have the fatty acid composition similar to that of the wild type and to develop aerial mycelium. The ratio of 12-methyltetradecanoic acid to palmitic acid might be used as a parameter to explain the optimum grwoth in the respect of membrane fluidity.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.155-160
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• 2003

The wild type and two morphological variants of Streptomyces viridochromogenes were studied for their lipidand fatty acid compositions at different incubation temperatures. It showed that a decrease in triacylglycerol content was closely linked to the aerial mycelium formation. Phospholipids showed no characteristic changes, except that the contents of phosphatidylethanolamine were clearly high for aerial mycelium deficient strain BR2 grown at $20^{\circ}C$. The strain BR2 also presented unidentified aminolipids with various $R_{f}$ values. Among the aminolipids, ornithinolipid increased gradually during the cultivation for all strains. The changes in fatty acid compositions showed a temperature dependency that the proportion of unsaturated acids decreased as the growth temperature increased. The proportion of straight chain saturated fatty acids decreased as the aerial mycelium developed, and it was most evident for the mutant strain M13 with more extensive aerial mycelium. The mutant strain BR2 presented significantly higher level of iso branched odd numbered saturated fatty acids.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.321-324
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• 2007

The changes in antigenicity during cultivation of streptomycetes were determined by immunodiffusion assay and indirect ELISA. New precipitin lines in immunodiffusion assay began to appear in the growth period of the soluble pigment production and became thickened thereafter. The increase in the antigenicity was also confirmed by ELISA. The antigenic development was relatively weak for S. lavendulae and S. viridochromogenes while that was strong for S. lavendulae and S. viridochromogenes. The results indicated that Streptomyces strains, even though not proved for some strains, changed the compositions of cell envelope during submerged growth and this could be estimated quantitatively by serological method.

• Journal of Life Science
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• v.11 no.1
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• pp.7-10
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• 2001

Nonactin is the parent compound of a group of ionophore antibiotics, that known as the macrotetrolides. In previous report, in th course of screening superoxide radical-generating compounds from microbial sources, we first screened Streptomyces viridochromogenes JM-4151 that produces nonactin. It was proved that nonactin is superoxide radical-producing compound. In present study, we examined the optimal culture conditions of nonacin. Th optimal culture conditions for nonactin production were as follows: 1% soluble starch, 1% yeast extract, 0.2% ammonium nitrate, 0.06% magnesium sulfate, 0.2% calcium carbonate, initial pH 7.0 at 28$^{\circ}C$ for 96 h. The highest nonactin production was achieved in the production medium of initial pH7.0 at 28$^{\circ}C$ for 96h. The threshold level of dissolved oxygen was found to be above 33.2% at 28$^{\circ}C$ when 1% soluble starch was used as a carbon source. These results suggest that S. viridochromogenes JM-4151 might be a possible strain for industrial nonactin producer.

• Journal of Life Science
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• v.10 no.1
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• pp.45-47
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• 2000

Nonactin, known as an ionophore antibiotic, was antagonized by the actibity of quercetin, an oxygen radical scavenger. This compound generated superoxide radicals in Bacillus subtilis lysates. A recombination-deficient mutant strain of B. subtilis was more sensitive than a wild strain, and this hypersensitivity was reduced in the presence of dithiothreitol as an antioxidant. These results suggest that superoxide radical is important in the antibacterial action of this agent.

• Korean Journal of Microbiology
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• v.43 no.2
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• pp.137-141
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• 2007

The similarities among five strains of Streptomyces were measured by the serological methods. Antigens were prepared by dissolving cell envelope fractions in Tween 20 buffer and antisera were produced from the immunized rabbits. Immunodiffusion studies and ELISA results showed that the degree of antigen-antibody reaction was not exactly matched to the taxonomic distance; i. e. the strains of the cluster group A exhibited low level of cross-reactions each other, while relatively strong cross-reactions were observed between Streptomyces lavendulae of cluster group F and Streptomyces viridochromogenes of cluster group A.

• Journal of Microbiology
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• v.40 no.1
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• pp.51-54
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• 2002

Heavy metal adsorptions of four streptomycetes were compared with each other, Among the test strains, Streptomyces viridochromogenes showed the most efficient metal binding activity, which was carried out by cell wall as well as freeze-dried mycelium. An order of adsorption potential (zinc > copper > lead > cadmium) was observed in single metal reactions, whereas this adsorption order was disturbed in mixed-metal reactions. The metal adsorption reactions were very fast, pH dependent and culture age-independen, suggestive of a physico-chemical reaction between cell wall components and heavy metal ions. The metal tolerant stains presented the weakest adsorbing activity, indicating that the metal biosorption was not the basis of the metal tolerance.