posted on November 26, 2012 by Webmaster
Marcus Roper, UCLA
Tuesday, November 27, 2012 4:30 pm Millikan Lab – Room 134
Fungi are the most diverse of all eukaryotic organisms and enjoy extraordinary ecological success as decomposers, pathogens and mutualists. Focusing on two problems of recent interest, I will discuss how this success may rest on their ability to solve hard physical problems:
#1. The forcibly launched spores of ascomycete fungi must eject through a boundary layer of nearly still air in order to reach dispersive air flows. Because of their microscopic size, singly ejected spores are almost immediately brought to rest by fluid drag. However, by coordinating the ejection of thousands or hundreds of thousands of spores, fungi such as the devastating plant pathogen Sclerotinia sclerotiorum, are able to create a flow of air that carries spores across the boundary layer and around any intervening obstacles.
#2. Time permitting, I will then show how the fungal mycelium itself is hydraulically engineered to create mixing flows of nuclei during growth. I hypothesize that these mixing flows are an adaptation that makes fungi very tolerant of chimerism: the presence of genetically different nuclei within the same organism. Chimeric fungi are known to be more adaptable and infectious than non-chimeric individuals, and are also thought to be key intermediate stages in the evolution of new species.