Secretion of five extracellular enzymes by strains of chromoblastomycosis agents

Abstract

SuMMaryThe gelatinase, urease, lipase, phospholipase and DNase activities of 11 chromoblastomycosis agents constituted by strains of Fonsecaea pedrosoi, F. compacta, Phialophora verrucosa, Cladosporium carrionii, Cladophialophora bantiana and Exophiala jeanselmei were analyzed and compared. All strains presented urease, gelatinase and lipase activity. Phospholipase activity was detected only on five of six strains of F. pedrosoi. DNase activity was not detected on the strains studied. Our results indicate that only phospholipase production, induced by egg yolk substrate, was useful for the differentiation of the taxonomically related species studied, based on their enzymatic profile.

Virulence markers of opportunistic black yeast in Exophiala

“…In this study, proteinase activity was observed in 1.8% of the environmental Exophiala isolates and in none of the clinical isolates. Consistent with our findings, phospholipase activity was not detected in a strain of E. jeanselmei from case of human chromoblastomycosis . However, Gugnani and Okeke evaluated 39 environmental dematiaceous opportunists and found positive phospholipase activity in two E. jeanselmei isolates.…”

“…DNases may enhance evasion of the innate immune response . DNase activity proved to be absent from E. jeanselmei . In our study, the enzyme was rarely found among the isolates tested, being limited to the most common opportunist, genotype A of E .…”

“…Despite the gamut of infections in immunocompetent patients caused by black yeast and related taxa, little is known about their virulence determinants . Members of the genus Exophiala are able to disseminate in an apparently healthy host and cause fatal disease, but do not seem to possess factors that enhance entry to the host; indeed, Exophiala infections are often implantation diseases generated by trauma.…”

Exophiala angulospora causes systemic ­inflammation in Atlantic cod Gadus morhua

“…LOD: limit of detection Note the diversity of conidium shape and size, ranging from short ellipsoid to more-or-less triangular to long ellipsoid (arrow) eased fish cannot be separated from isolates ob tained from other substrates such as wood and water, at least not with the currently used genetic marker, it is likely that E. angulospora is an opportunistic pathogen not restricted to a pathogenic life history. Species of Exophiala are known to produce a variety of extracellular en zymes, including ureases, gelatinases, and lipases (De Souza et al 2008, Corbellini et al 2009). Effects of extracellular enzymes on fish host cells may explain why dead cells were observed in layer 1 of the foci where abundant fungal hyphae were present, but not in the layers containing few hyphae.…”

Exophiala xenobiotica aerocystitis in a Queensland grouper Epinephelus lanceolatus (Bloch)

“…Necrotizing extracellular enzymes released by the fungus may be a contributing factor as well (de Souza et al . ). Fungal melanin likely plays a protective role in the environment and serves as a virulence factor, providing protection from the effects of hydrolytic enzymes and free radicals produced by phagocytes (Revankar & Sutton ).…”