ibclogo XVI International Botanical Congess


Abstract Number: 2373
Poster No. = 2092


PENTAKETIDE MELANIN BIOSYNTHESIS IN SPOROTHRIX SCHENCKII


M. Wheeler*, R. Romero**, A. Guerrero-Plata** and H. Torres-Guerrero**. *CPRU, USDA, ARS, College Station, TX, **Universidad Nacional Autonoma de Mexico, Mexico, D.F.


Sporothrix schenckii causes sporotrichosis, a human cutaneous mycosis. It produces dark conidia which infect the host. We found that S. schenckii synthesizes melanin via the 1,8-dihydroxynaphthalene pathway. Two melanin deficient mutants were analyzed in the study: an albino that produced normal appearing melanin on a scytalone amended medium, and a reddish-brown mutant that secreted scytalone and flaviolin into the medium. TEM showed an electron dense granular material in wild type conidial cell walls believed to be melanin, and this was absent in conidial walls of the albino unless the albino was grown on scytalone amended medium. Melanin protected S. Schenckii against UV light, certain oxidative compounds, and attack by macrophages.


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