|
Abstract: Development of Schizophyllum commune may be divided into four phases (1) nondifferentiated growth, (2) initiation of primordia and continued production of nondifferentiated hyphae, (3) growth of primordia, and (4) formation of pilei. Phases 1 and 2 depend on the supply of carbohydrate and N from the medium. Phase 3 can proceed in the absence of an external N supply, the N requirements being met by withdrawal of N compounds from the mycelium. An external C supply is indispensable in this phase, a large fraction of absorbed sugar is converted into cellular carbohydrates. The processes in phase 4 draw completely upon endogenous compounds, suggesting a flow of material from stunted fructifications and mycelium to developing fruit bodies. The bulk of the cellular carbohydrates is located in the cell walls. Their chemical analysis shows them to be mainly composed of two glucans termed S- and R-glucan, some properties of which were investigated Pileus formation is accompanied by degradation of these glucans in stunted fructifications and mycelium. The ability to break down these glucans is absent in a strain in which pileus formation is inpaired ('cup' mutant), it is suppressed in the wild strain if grown at an elevated temperature which prevents the formation of fruit bodies. The fact that the morphogenetic deficiency of the cup mutant cannot be simply overcome by supplying more glucose suggests that a steady low concentration of glucose (or another soluble degradation product of the cell-wall glucans) is essential for pileus formation. Strong evidence was obtained in favour of such a regulatory mechanism, it is possible to inhibit pileus formation in the wild strain and to induce pilei in the cup mutant by manipulating the concentration of glucose in the medium.
Full text download: ISMS subscribers
ISHS members & pay-per-view
Translate:
   |