Lxxi. Studies in the Biochemistry of Micro-organisms

THE name Aspergillus terreus is used by Thom and Church [1918; 1926] to cover a series of strains which have a number of well-marked morphological features in common, but which show a certain amount of variation in colour and type of growth. The conidial colour may range from pale cinnamon to fairly deep brown; the texture of the surface growth may vary from smooth velvety to definitely floccose, whilst the reverse of the colony and the agar may vary in colour from pale or bright yellow to fairly dark brown. Thom and Church state that A. terreus is common in soil and decaying vegetable matter throughout the United States, but has not been received by them from any European source. Smith [1928] found this organism as a latent infection of cotton yarns, occurring fairly often on American cottons and very frequently on all types of Egyptian cottons; also as a cause of serious damage to exported cloths, particularly dhooties. The present communication is an account of experiments which have been carried out with five strains of A. terreus, obtained from different sources and covering approximately the range of variation sho'wn by different strains in the series. When grown at 24° on the well-known Czapek-Dox solution with 5 % of glucose as the sole source of carbon, two of the strains, No. 45 and Ac 100, produce in the solution a new mould metabolic product which we have named terrein (CAH1003, M.P. 1270).1 The yield of terrein appears to reach a maximum when the sugar in solution has been reduced to approximately 1 %. Succinic acid has also been identified as a metabolic product of No. 45, but is formed in small amounts only. From the metabolism solutions of the remaining three strains (No. 3, No. 37 and Ac 24) no terrein has been isolated but only small amounts of oxalic acid, succinic acid or both. The strain Ac 100 is of special interest since it produces, in addition to the new product terrein, appreciable quantities of citrinin, a substance hitherto believed to be formed only by Penicillium citrinum Thom [Hetherington and Raistrick, 1931]. The other four strains also give rise to fairly large amounts of substances which, like citrinin, are precipitated by acidification of the metabolism solutions. From none of these acid precipitates has any citrinin been obtained and so far no other substance has been isolated in a state of purity.