Histone methylation plays a key role in establishing and maintaining stable gene expression patterns during cellular differentiation and embryonic development. Here, we report the characterization of the fungal metabolite chaetocin as the first inhibitor of a lysine-specific histone methyltransferase. Chaetocin is specific for the methyltransferase SU(VAR)3-9 both in vitro and in vivo and may therefore be used to study heterochromatin-mediated gene repression.

A multicopper oxidase gene from the human pathogenic yeast Candida albicans was isolated and characterized. An open reading frame of 1872 bp, designated CaFET3, was identified, encoding a predicted protein of 624 amino acids and a molecular mass of 70 5 kDa. The identity between the deduced amino acid sequences of CaFET3 and the Saccharomyces cerevisiae FET3 gene is 55 %. CaFET3 was localized on chromosome 6. A null mutant (fet3∆/fet3∆) was constructed by sequential gene disruption. Unlike the C. albicans SC5314 wildtype strain the fet3∆ mutant was unable to grow in low-iron medium. The lack of growth of a S. cerevisiae fet3∆ mutant in iron-limited medium was compensated by transformation with CaFET3. The null mutant strain showed no change in pathogenicity compared with the wild-type strain in the mouse model of systemic candidiasis.

Out of the brew! Four new antibiotics were isolated from a fermentation broth of Steptomyces lydicus (strain HKI0343). The 13‐membered‐ring peptides (see formula, XY: CH2NH, CHNH; R1, R2: H, OH) are cyclized through a lactone function at serine and also contain the nonproteinogenic amino acid piperazic acid (or a derivative thereof). The peptides show promising activity against various mycobacteria without being cytotoxic.