to the Growth Cycle of Penicillium charlesii

Clutterbuck et al. (1934) reported that the metabolic products of the mould Penicillium charlesii G. Smith grown on glucose as the carbon and energy source were two polysac-charides and six organic acids- carolic, carlosic, carlinic, carolinic, verticillic and rami-genic acids. Subsequent work showed that verticillic acid and ramigenic acid were artefacts arising from the reaction between a further acid product, y-methyltetronic acid, and the acetone used in the extraction procedure (Clutterbuck, Raistrick & Reuter, I 935). Later workers studying the organic acid products have failed to agree as to the number and type of metabolites produced. Bentley, Bhate & Keil (1962) and R. Bentley (personal communication) failed to detect all the tetronic acids originally reported; whilst Lybing & Reio (1958) showed that, at least under certain conditions, itaconic acid was produced. The data reported in this paper support the claim of Bentley et al. (1962), in that only three tetronic acids were detected. The time of initiation suggested that these occurred as secon-dary metabolic products. Itaconic acid was also detected in the culture medium but was only formed during the primary growth phase