No abstract

EChlhl 200215 and ~WlTfl. However, among serotype A population, only I\MTP strains were identified. Recently an Italian environmental isolate was recovered and found to be haploid, serotype A, and hybridized to a kL-ITa-specific probe. Crosses between IUM 96-2828 and other strains of both mating types revealed that this strain mated only as MAE. A mating reaction between IUhl 96-2828 and H99 (serotype AMATP) produced abundant spores. Analysis of these spores revealed an equal distribution of A U T a and MAT@ progeny and all progeny were serotype A. Karyotypic analysis of progeny spores revealed evidence of recombination, confirming that IUhl 96-2828 was fertile. The MAE pheromone gene from IUhl 96-2828 was cloned and sequenced. The predicted peptide (hlFa1Ap) exhibited substantial, but not identical, sequence homology to the serotype D .MAXI pheronione. Sequence comparison to a number of pheromone genes revealed MFa1A to be most closely related to the serotype D MAE pheromone. Phylogenetic comparisons of other genes confirmed that IUhl96-2828 was most closely related to serotype A strains. Assays for capsule, melanin and phospholipase activity found no difference between H99 and IUhl96-2828, nor was there any difference in growth rate at 37"C, however, when virulence was compared to H99 using the mouse model, IUhl96-2828 was significantly less virulent. Grant hlIUR 200 106522 1