ANTHONY-H-ROSE-MEMORIAL-LECTURE - THE INS AND OUTS OF THE YEAST PLASMA-MEMBRANE

The last three pieces of research associated with the late Anthony H. Rose, Professor of Microbiology at the University of Bath, are reviewe d. The second messenger cyclic AMP was shown to vary up to 70-fold in concentration during the growth of batch cultures of Saccharomyces cer evisiae with different media. It seems to have a role in transducing i nformation on actual levels of extracellular residual carbon source as well as entry into stationary phase. Another second messenger pathway , involving hydrolysis of phosphatidylinositol bisphosphate, was shown not to be glucose-stimulated as previously thought. Inositol trisphos phate kinase activity was detected but both the existence of the compl ete pathway and its role were unclear. The yeast Kluyveromyces marxian us isolated from cocoa fermentations was shown to produce abundant and almost pure endo-polygalacturonase in a constitutive manner. Some str ains of Saccharomyces cerevisiae also secrete this pectinolytic enzyme . All three projects relate to the central role of membranes in regula ting transport of either sensory information or molecules in and out o f cells, a key focus of his research for thirty years.