The nutritional requirements of haustorial mycoparasites remain uncertain, even though extensive axenic growth of certain mycoparasites has been obtained following the addition of a growth factor, mycotrophein, to an appropriate basal medium (Barnett & Lilly, 1958; Whaley & Barnett, 1963; Gain & Barnett, 1970; Calderone & Barnett, 1972). Limited growth of mycoparasites in the absence of host extracts has been reported for Syncephalis (Ellis, 1966) and Dispira parvispora (Brunk & Barnett, 1966). Barnett (1970) successfully cultured four haustorial mycoparasites including Dispira cornuta on a glycerol-casein hydrolysate medium, and Binder & Barnett (1974) reported excellent axenic growth of Tieghenzionzyces parasiticus on a glycerol-casein hydrolysate or amino acid medium,

There are different reports regarding the nutrition of D. cornuta. Ayers (1933) reported abundant axenic growth on natural media such as meat, fish and eggs. However, Kurtzman (1968) was unable to confirm Ayers' results. Out of five isolates of D. cornuta studied by Kurtzman only three made fair axenic growth on glycerol or acetate media in the presence of host extract, and these three isolates failed to utilize glucose. Using Kurtzman's isolate I, Barker & Barnett (1973) reported that, in a medium containing glycerol, increasing amounts of casein hydrolysate, L-glutamic acid and L-aspartic acid supported correspondingly increasing amounts of growth, with an optimum at 40g/l. L-Aspartic acid was the best nitrogen source. How such large amounts of L-aspartic acid and L-glutamic acid were kept in solution when the solubilities of these amino acids at 25 °C are 5 and 8-64 g/1 respectively was not explained. It is therefore doubtful whether either of these amino acids was completely dissolved at the optimum concentration for the growth of the fungus (40 g/l).


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