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NUTRITIONAL STUDIES OF ASCOBOLUS IMMERSUS
Author(s) -
YuSun Clare C. C.
Publication year - 1964
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1964.tb06625.x
Subject(s) - dextrin , sorbose , sorbitol , citric acid , chemistry , food science , sucrose , lactose , urea , mannitol , fructose , botany , biology , biochemistry , starch
A synthetic medium for vegetative growth and apothecial formation of 2 compatible strains of A immersus has been formulated as follows: KH 2 PO 4 , 0.5 g; K 2 HPO 4 , 0.6 g; MgSO 4 ·7H 2 O, 0.5 g; micronutrients, 0.1 ml (Vogel's); asparagine, 5 g (for vegetative growth), or urea, 1 g (for apothecial formation); dextrin (Merck), 20 g; biotin, 5 μg; thiamine, 100 μg; and distilled water, 1 liter. This medium had a pH of 6.2 to 6.7 without adjustment and was satisfactory. For apothecial formation, 20 g Noble agar (Difco) and 2 g cellulose powder (Whatman) were added to the above medium. Apothecial formation was better at 23–24 than at 25–26 C. Light was necessary for apothecial formation. Dextrin, soluble starch, glucose and mannose were satisfactory carbon sources for both vegetative growth and apothecial formation. This fungus could not use lactose, sucrose, sorbose, mannitol, sorbitol or insulin as carbon sources. It could assimilate nitrate in the form of KNO 3 . Optimum yields were obtained with asparagine, aspartic acid, or glutamic acid as the source of nitrogen. The optimum nitrogen‐carbon ratio for apothecial formation was about 2% dextrin and 0.1% urea. This ratio was given the highest apothecial rating 10. Ascobolus immersus was deficient in the ability to synthesize biotin and thiamine.