Humans and animals are exposed to aflatoxins, toxic carcinogenic fungal metabolites, through consumption of contaminated food and feed. Aspergillus flavus, the primary causal agent of crop aflatoxin contamination, is composed of phenotypically and genotypically diverse vegetative compatibility groups (VCGs). Molecular data suggest that VCGs largely behave as clones with certain VCGs exhibiting ...

Dead and dying oak (Quercus) and numerous other woody ornamental trees and shrubs showing signs and symptoms of Armillaria root rot were identified in the Company Gardens, Cape Town, South Africa, which were established in the mid-1600s by the Dutch East Indies Trading Company. Nineteen isolates from dying trees or from mushrooms were collected and analysed to identify and characterize the Armi...

Experimental investigations of homomorphic self-incompatibility (SI) have revealed an unanticipated level of complexity in its expression, permitting fine regulation over the course of a lifetime or a range of environmental conditions. Many flowering plants express some level of clonal reproduction, and phylogenetic analyses suggest that clonality evolves in a correlated fashion with SI in Sola...

The concepts of self and nonself have been a subject of much study and discussion in biology and philosophy. A signifi cant volume of research on the subject has answered some but also generated many more questions. What defi nes self? What mechanisms control self and nonself recognition? What is the purpose of such a recognition system? A product of the post-World War II early immunology movem...

The heterokaryotic condition, first described by Dodge (1927) in N. tetrasperma, provided a ready means for determining the dominance of traits expressed in the haploid vegetative phase. Heterokaryons also seemed to offer a novel genetic system, in contrast to diploidy. The advent of recessive auxotrophic mutations in 1941 provided a means of selecting heterokaryons composed of strains with com...