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. 1982 Jun;36(3):1175–1184. doi: 10.1128/iai.36.3.1175-1184.1982

Phenoloxidase activity and virulence in isogenic strains of Cryptococcus neoformans.

J C Rhodes, I Polacheck, K J Kwon-Chung
PMCID: PMC551454  PMID: 6807845

Abstract

A naturally occurring Mel- variant of Cryptococcus neoformans was isolated from the wild type. The effect of phenoloxidase activity on virulence was analyzed on genetically constructed Mel+ and Mel- isolates. The traits Mel+ and virulence in mice, as measured by cumulative mortality and replication potential in brain tissue, cosegregated among the progeny of a Mel+ X Mel- cross. Revertants (MelR) isolated during the course of the cumulative mortality experiment were used to compare virulence in isogenic sets of Mel- and MelR. In two separate sets of such isolates, Mel+ phenotype and virulence coreverted. Measurement of substrate uptake and phenoloxidase activity showed that loss of detectable phenoloxidase was the basis for the Mel- phenotype and that enzyme activity reappeared in the MelR isolates. An intermediate phenotype, Melbg, was also described. Cosegregation and coreversion of the melanin phenotype and virulence suggest that phenoloxidase is a virulence factor in C. neoformans.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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