John B. Routien

Increased Sporulation in Fungi

There are certain fungi, however, which cannot be freeze-dried successfully either due to lack of spore production or the presence of too few spores. These fungi must be maintained in test tubes on agar slants, kept at low temperatures, and subjected to repeated subculturing at periodic intervals. Of equal importance to the inconvenience which this procedure entails are the aspects of increased genetic instability and possibilities of contamination. A portion of our culture collection consists of fungi which fall in the above-mentioned category. Some of these fungi have become asporogenous through repeated subculturing. Some, however, were asporogenous when obtained from our soil screening program, and some were asporogenous when obtained from reputable culture collections. A preliminary investigation 2 of a variety of nutrients for growthpromoting effects in several fungi and streptomycetes led to the observation that certain media supplemented with coconut milk enhanced growth in some of these micro-organisms. In view of this finding and the desirability of increasing sporulation for identification, freeze-drying, and other processes requiring large numbers of spores it was decided to grow our collection of asporogenous or weakly sporogenous fungi on media supplemented with coconut milk. Fungi which still failed to sporulate were further tested on a medium containing tomato paste and oatmeal.