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Serial dilution of basidiospores of a spore print to prepare grain spawn of the Oyster mushroom is described. The method, which has a contamination rate of about 5%, requires sterilization of a grain medium and the use of some simple “clean” procedures. The method is especially advantageous for small scale and part-time cultivation of mushrooms on logs. Pleurotus ostreatus Kumm. mycelium grew rapidly into the wood of freshly cut logs inoculated with disks of grain spawn prepared using spore inoculum. Unlike pure-culture spawn disks, however, disks prepared from spore-inoculated grain did not become completely tightly bonded to the wood surface.

Corey published a leading paper in 196 7 demonstrating that 2, 3-iminosqualene inhibited the cyclization of squalene-oxide to lanosterol in a cell-free system1. In the interim years between then and this seventh international plant lipid symposium, four groups-one each in the United States2, Canada3 another in France4 and Italy4, have firmly established the mechanistic and biological importance of using this and structurally related molecules, e.g. 25-azasteroids5, to interfere with fungal sterol biosynthesis which results in diminished growth response. Industry and biotechnology firms have followed suit in recent years designing analogous inhibitors6, 7 which they believe may have potential promise in plant protection. On the premise that specific N-isopentenoids induce alterations in sterol biosynthesis which in turn may create a pathologic state in the structure and function of membranes of pathogenic fungi, we began a chemical synthesis program in 1984 by preparing blockers targeted at fungal lipid biosynthesis.

Summary When cultures of Gibberella fujikuroi are incubated with 24-epiiminolanosterol the introduction of a methyl group into sterol side chains at C-24 is blocked inducing a mycelial accumulation of lanosterol and 24-desalkylsterols, i.e., having the cholestane side chain. The altered sterol composition lead to aberrant mycelial membranes resulting in growth inhibition. A compensatory physiological response to the ensuing hyphal death was induction of asexual sporulation. The results are interpreted to imply that regulation of sterol C-24 transalkylation may be a mechanism to mediate life cycle events of fungi.

There are two major lipid pathways which operate in crop plants viz., the isopentenoid and fatty acid pathways. To our knowledge, no previous investigation has attempted a comparative study of the composition, biosynthesis and function of the major end products of these pathways. However, in order to assess the physiological importance of having a select lipid profile to, for instance, proceed from one developmental stage into another, the lipid composition in toto-subcellular and surface wax, must be defined. As discussed in what follows, we have observed in this and our other work on sorghum1–5 that the lipid profile changes dramatically during its development (Table 1). Thus, lipids essentially absent, i.e., pentacyclic triterpenoids, in the seedlings become quantitatively important bulk constituents of the blade’s membrane and wax architectures as the plant enters into the flowering stage. Other membrane components have been identified by GLC-MS and ‘HNMR eg., fatty acids (myristate, palmitate, oleate, linoleate and linolinate), long chain fatty alcohols (C22-C32-Table 2) and alkanes in the blades.