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Identification and molecular characterization of the homogentisate pathway responsible for pyomelanin production, the major melanin constituents in Aeromonas media WS.

Wang H, Qiao Y, Chai B, Qiu C, Chen X - PLoS ONE (2015)

Bottom Line: This HGA biosynthesis pathway is widely distributed in Aeromonas, but HGA is only detectable in the cultures of pigmented Aeromonas species.Heterologous expression of HppD from both pigmented and non-pigmented Aeromonas species in E. coli leads to the production of pyomelanin and thus pigmentation, suggesting that most Aeromonas species have the critical enzymes to produce pyomelanin through HGA.Taken together, we have identified a widely conserved biosynthesis pathway of HGA based pyomelanin in Aeromonas that may be responsible for pigmentation of many Aeromonas species.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.

ABSTRACT
The pigmentation of many Aeromonas species has been thought to be due to the production of a L-DOPA (L-3,4-dihydroxyphenylalanine) based melanin. However, in this study we found that although L-DOPA synthesis occurs in the high-melanin-yielding Aeromonas media strain WS, it plays a minor, if any, role in pigmentation. Instead, the pigmentation of A. media strain WS is due to the production of pyomelanin through HGA (homogentisate). Gene products of phhA (encodes phenylalanine hydroxylase), tyrB and aspC (both encode aromatic amino acid aminotransferase), and hppD (encodes 4-hydroxyphenylpyruvate dioxygenase) constitute a linear pathway of converting phenylalanine to HGA and disruption of any one of these genes impairs or blocks pigmentation of A. media strain WS. This HGA biosynthesis pathway is widely distributed in Aeromonas, but HGA is only detectable in the cultures of pigmented Aeromonas species. Heterologous expression of HppD from both pigmented and non-pigmented Aeromonas species in E. coli leads to the production of pyomelanin and thus pigmentation, suggesting that most Aeromonas species have the critical enzymes to produce pyomelanin through HGA. Taken together, we have identified a widely conserved biosynthesis pathway of HGA based pyomelanin in Aeromonas that may be responsible for pigmentation of many Aeromonas species.

No MeSH data available.


Related in: MedlinePlus

HPLC analysis.Detection of the intermediates from cultures of A. salmonicida_AB98041, A. salmonicida KACC14791 and A. hydrophila_XS91-4-1. Samples were taken after 36 h of growth in LB. (A) Analysis of HGA. (B) Analysis of L-DOPA. HGA Standard: commercial HGA (Sigma); DOPA Standard: commercial L-DOPA (Sigma).
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pone.0120923.g008: HPLC analysis.Detection of the intermediates from cultures of A. salmonicida_AB98041, A. salmonicida KACC14791 and A. hydrophila_XS91-4-1. Samples were taken after 36 h of growth in LB. (A) Analysis of HGA. (B) Analysis of L-DOPA. HGA Standard: commercial HGA (Sigma); DOPA Standard: commercial L-DOPA (Sigma).

Mentions: To further test our hypothesis that pigmentation of Aeromonas species is dependent on pyomelanin synthesis through HGA, we examined whether HGA production correlates with pigmentation in various Aeromonas species. We expected to detect HGA in the cultures of pigmented Aeromonas species but not in those of the non-pigmented ones. To this end, we cultured the pigmented A. salmonicida, and the non-pigmented strain A. hydrophila in LB at 22°C, 30°C, respectively, and tried to detect HGA in their culture supernatants by HPLC. As showed in Fig. 8A, HGA was detected in the 36 h culture supernatants of A. salmonicida_AB98041 and A. salmonicida KACC14791 but not in that of A. hydrophila (a pattern similar to A. media strain WS was found for the two pigmented A. salmonicida, but only the data for 36 h culture supernatant was showed for simplicity). As a control, we also tested the presence of L-DOPA in the culture supernatants of these three species. Unlike HGA, L-DOPA was detected in the culture supernatants of both A. salmonicida_AB98041 and A. salmonicida KACC14791 as well as in that of A. hydrophila (Fig. 8B). Therefore, there is a strong correlation between the production of HGA and pigmentation but no correlation between the production of L-DOPA and pigmentation in many Aeromonas species.


Identification and molecular characterization of the homogentisate pathway responsible for pyomelanin production, the major melanin constituents in Aeromonas media WS.

Wang H, Qiao Y, Chai B, Qiu C, Chen X - PLoS ONE (2015)

HPLC analysis.Detection of the intermediates from cultures of A. salmonicida_AB98041, A. salmonicida KACC14791 and A. hydrophila_XS91-4-1. Samples were taken after 36 h of growth in LB. (A) Analysis of HGA. (B) Analysis of L-DOPA. HGA Standard: commercial HGA (Sigma); DOPA Standard: commercial L-DOPA (Sigma).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4368426&req=5

pone.0120923.g008: HPLC analysis.Detection of the intermediates from cultures of A. salmonicida_AB98041, A. salmonicida KACC14791 and A. hydrophila_XS91-4-1. Samples were taken after 36 h of growth in LB. (A) Analysis of HGA. (B) Analysis of L-DOPA. HGA Standard: commercial HGA (Sigma); DOPA Standard: commercial L-DOPA (Sigma).
Mentions: To further test our hypothesis that pigmentation of Aeromonas species is dependent on pyomelanin synthesis through HGA, we examined whether HGA production correlates with pigmentation in various Aeromonas species. We expected to detect HGA in the cultures of pigmented Aeromonas species but not in those of the non-pigmented ones. To this end, we cultured the pigmented A. salmonicida, and the non-pigmented strain A. hydrophila in LB at 22°C, 30°C, respectively, and tried to detect HGA in their culture supernatants by HPLC. As showed in Fig. 8A, HGA was detected in the 36 h culture supernatants of A. salmonicida_AB98041 and A. salmonicida KACC14791 but not in that of A. hydrophila (a pattern similar to A. media strain WS was found for the two pigmented A. salmonicida, but only the data for 36 h culture supernatant was showed for simplicity). As a control, we also tested the presence of L-DOPA in the culture supernatants of these three species. Unlike HGA, L-DOPA was detected in the culture supernatants of both A. salmonicida_AB98041 and A. salmonicida KACC14791 as well as in that of A. hydrophila (Fig. 8B). Therefore, there is a strong correlation between the production of HGA and pigmentation but no correlation between the production of L-DOPA and pigmentation in many Aeromonas species.

Bottom Line: This HGA biosynthesis pathway is widely distributed in Aeromonas, but HGA is only detectable in the cultures of pigmented Aeromonas species.Heterologous expression of HppD from both pigmented and non-pigmented Aeromonas species in E. coli leads to the production of pyomelanin and thus pigmentation, suggesting that most Aeromonas species have the critical enzymes to produce pyomelanin through HGA.Taken together, we have identified a widely conserved biosynthesis pathway of HGA based pyomelanin in Aeromonas that may be responsible for pigmentation of many Aeromonas species.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.

ABSTRACT
The pigmentation of many Aeromonas species has been thought to be due to the production of a L-DOPA (L-3,4-dihydroxyphenylalanine) based melanin. However, in this study we found that although L-DOPA synthesis occurs in the high-melanin-yielding Aeromonas media strain WS, it plays a minor, if any, role in pigmentation. Instead, the pigmentation of A. media strain WS is due to the production of pyomelanin through HGA (homogentisate). Gene products of phhA (encodes phenylalanine hydroxylase), tyrB and aspC (both encode aromatic amino acid aminotransferase), and hppD (encodes 4-hydroxyphenylpyruvate dioxygenase) constitute a linear pathway of converting phenylalanine to HGA and disruption of any one of these genes impairs or blocks pigmentation of A. media strain WS. This HGA biosynthesis pathway is widely distributed in Aeromonas, but HGA is only detectable in the cultures of pigmented Aeromonas species. Heterologous expression of HppD from both pigmented and non-pigmented Aeromonas species in E. coli leads to the production of pyomelanin and thus pigmentation, suggesting that most Aeromonas species have the critical enzymes to produce pyomelanin through HGA. Taken together, we have identified a widely conserved biosynthesis pathway of HGA based pyomelanin in Aeromonas that may be responsible for pigmentation of many Aeromonas species.

No MeSH data available.


Related in: MedlinePlus