Presence of chitin in the cell wall of a griseofulvin-producing species of penicillium.

It has been suggested (P. W. Brian, Trans. Brit. Mycol. Soc. 43:1, 1960) that the antibiotic griseofulvin affects only those fungi possessing chitin in their cell wall, but there is a growing body of evidence which makes it unlikely that the presence of chitin is the sole prerequisite for the action of the antibiotic. For instance, K. J. Bent and R. H. Moore (Biochemical Studies of Anti-microbial Drugs, Cambridge Univ. Press, London, 1966) reported that the chitin content of whole mycelia of Botrytis allii increased after griseofulvin treatment rather than decreased, and D. E. Eveleigh and S. G. Knight (Bacteriol. Proc., p. 27, 1965) found that the glucosamine-toglucose ratio of the cell wall of Trichophyton mentagrophytes is unchanged by griseofulvin. This communication reports the presence of chitin in the cell wall of Penicillium patulum, when it was grown under conditions which permitted the production of griseofulvin. P. patulum was obtained through the courtesy of R. S. C. Aytoun of Glaxo Research Ltd., Buckinghamshire, England. It was grown in surface culture in a fully synthetic medium (D. A. Applegarth, Arch. Biochem. Biophys. 120:471, 1967). The medium was supplemented by the addition of sodium chloride (0.2 g/liter) to provide the chlorine atoms of the griseofulvin molecule. The mycelial pads were harvested after 7 days, and the contents of one of the flasks was dried and analyzed for griseofulvin according to the method of A. Holbrook, F. Bailey, and G. M. Bailey (J. Pharm. Pharmacol. 15(Suppl.): 270, 1963). The 7-day mycelial growth from each liter of solution contained approximately 8 mg of griseofulvin. Cell walls were prepared from the mycelial pads in the remaining flasks by ballistic disruption of the hyphae with glass beads in a Sorvall Omnimixer (D. A. Applegarth, Arch. Biochem. Biophys. 120:471, 1967). The purified cell walls contained 12.3% glucosamine and a trace of galactosamine (approximately 0.5%). The hexosamines were eluted from Whatman 3MM paper developed with n-butanolacetic acid-water (4:1:5, v/v). Their identity was established by co-chromatography, with authentic standards, in three solvent systems; by ninhydrin oxidation (P. J. Stoffyn and R. W. Jeanloz, Arch. Biochem. Biophys. 52:373, 1954); and by Nacetylation followed by chromatography in three solvent systems. The identity of the glucosamine polymer as chitin was established as follows. Cell walls (10 mg) were extracted with 1 N acetic acid (5 ml) at 100 C for 20 min. The acid extract was removed by centrifugation, and Gram's iodine solution was added to the extract. No color was obtained. This suggested that the walls did not contain chitosan. The residual walls