Melanin and novel melanin precursors from Aeromonas media

Gibson, L. F.

doi:10.1016/s0378-1097(98)00495-9

Cited by 9 publications

(21 citation statements)

References 16 publications

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“…media , the strain WS, which produces high levels of melanin, with a yield of 1720 ppm in 72 h. Although some isolates of A . media are known to produce red, yellow or brown pigments (Gibson and George 1998), our strain appears to be the best melanin producer among them. Further attempts, including the use of genome shuffling method (Zhang et al.…”

Section: Discussionmentioning

confidence: 84%

Isolation of a novel strain of Aeromonas media producing high levels of DOPA-melanin and assessment of the photoprotective role of the melanin in bioinsecticide applications

Wan

Liu²,

Liao

et al. 2007

Journal of Applied Microbiology

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Aims: To isolate a bacterium that produces high yield of melanin and to examine the effect of this bacterial pigment on the efficacy of a bioinsecticide. Methods and Results: A novel melanin‐producing bacterium, designated as strain WS, was isolated from the East Lake, Wuhan, China. Taxonomic studies of this strain indicate that it belongs to Aeromonas media. Physicochemical analysis of the pigment produced by strain WS (melanin WS) suggests that it is the authentic 3,4‐dihydroxyphenylalanine (DOPA)‐melanin. This melanin and that produced by Pseudomonas maltophilia P28 (melanin P28) share many biophysical properties, but the yield of the melanin WS is significantly higher than that of the melanin P28. In addition, the melanin WS appears to be more effective in the protection of a bioinsecticide against ultraviolet (UV) or solar radiation. At the concentration of 10 ppm, the melanin P28 exhibited no photoprotective effect on the bioinsecticide against UV radiation; in contrast, 5 ppm of melanin WS displayed an obvious protective effect. Similarly, the melanin WS displayed more protective effect on the bioinsecticide against solar radiation than the melanin P28 did over a 4‐day period, with the effect being more dramatic for the last 2 days. Conclusions: We have isolated a novel bacterial strain of A. media that produces high levels of melanin. The melanin produced by this strain offers effective photoprotection of a commercial bioinsecticide BTI against UV and solar radiation. Significance and Impact of the Study: Our study suggests that the melanin produced by our newly isolated A. media strain has the potential to be used as a general photoprotective agent for bioinsecticides.

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Section: Discussionmentioning

confidence: 84%

Isolation of a novel strain of Aeromonas media producing high levels of DOPA-melanin and assessment of the photoprotective role of the melanin in bioinsecticide applications

Wan

Liu²,

Liao

et al. 2007

Journal of Applied Microbiology

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“…The presence of a dark brown color in bacterial cultures is characteristic of the production of melanin or a melanin-type polymer that can be collected from culture broth by acid precipitation (15). Upon acidification of the P57G4 culture broth, a dark brown precipitate formed, suggesting the presence of melanin in the culture.…”

Section: Resultsmentioning

confidence: 99%

“…Upon acidification of the P57G4 culture broth, a dark brown precipitate formed, suggesting the presence of melanin in the culture. The dark brown material in the acid precipitate harvested from the P57G4 broth, like other bacterial melanins (15,39), was insoluble in aqueous acid, was soluble in aqueous base, bound to an anion-exchange column (DEAE-cellulose), and was Ͼ7,000 Da.…”

Section: Resultsmentioning

confidence: 99%

Isolation of Antibiotics Turbomycin A and B from a Metagenomic Library of Soil Microbial DNA

Gillespie

Brady

Bettermann

et al. 2002

Appl Environ Microbiol

429

244

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Three clones, P57G4, P89C8, and P214D2, produced colonies with a dark brown melanin-like color. We fractionated the culture supernatant of P57G4 to identify the pigmented compound or compounds. Methanol extracts of the acid precipitate from the culture supernatant contained a red and an orange pigment. Structural analysis revealed that these were triaryl cations, designated turbomycin A and turbomycin B, respectively; both exhibited broad-spectrum antibiotic activity against gram-negative and gram-positive organisms. Mutagenesis, subcloning, and sequence analysis of the 25-kb insert in P57G4 demonstrated that a single open reading frame was necessary and sufficient to confer production of the brown, orange, and red pigments on E. coli; the predicted product of this sequence shares extensive sequence similarity with members of the 4-hydroxyphenylpyruvate dioxygenase (4HPPD) family of enzymes. Another member of the same family of genes, lly, which is required for production of the hemolytic pigment in Legionella pneumophila, also conferred production of turbomycin A and B on E. coli. We further demonstrated that turbomycin A and turbomycin B are produced from the interaction of indole, normally secreted by E. coli, with homogentisic acid synthesized by the 4HPPD gene products. The results demonstrate successful heterologous expression of DNA extracted directly from soil as a means to access previously uncharacterized small organic compounds, serving as an example of a chimeric pathway for the generation of novel chemical structures.

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“…These substances can be found in plants, animals and microorganisms (Bell and Wheeler, 1986;Kotob et al, 1995;Hill, 1997;Gibson and George, 1998;Prota et al, 1998;Sarna and Swartz, 1998). In plants, a compound known as phytomelanin (or phytomelan) is present in the seed coat some taxa of Asparagales (Dahlgren and Clifford, 1982) and the fruits of certain Compositae (Pandey and Singh, 1982;Pandey et al, 1989;Marzinek et al, 2008.…”

Section: Introductionmentioning

confidence: 99%