Non-conventional infections elements in filamentous fungi

Old data (most often in French) described phenomena involving non-conventio nal infectious factors in filamentous fungi. Recently, it was shown that tw o yeast cytoplasmic determinants are similar to known mammalian prions, in that their different states are attributed to conformational changes of nor mal cellular proteins. In the light of this discovery, fungal elements are now being reconsidered. This review presents four elements that affect vege tative incompatibility, conidiogenesis, morphology and cell growth. Recentl y, one element has been shown to be a prion analogue. The status of the oth ers is not clear. We consider the view that nan-conventional inheritance mi ght be initiated by the appearance, in the cytoplasm, of a metabolite or a macromolecule whose production involves a positive regulatory loop.