tailieunhanh - Ebook Current topics in medical mycology (Vol.4): Part 2

(BQ) Part 2 book “Current topics in medical mycology” has contents: Killer system interactions, allylamine antifungal drugs, teaching medical mycology in latin america, the' need for a national mycoses reporting system, and other contents. | 5-Killer System Interactions L. POLONELLI, G. MORACE, S. CONTI, M. GERLONI, W. MAGLIANI, AND C. CHEZZI Viruses and Fungi Over the last few years, our concept of yeasts has changed vastly. Once thought of as "E. coli with a nucleus,"l these organisms currently represent cells of universal use by modern molecular biologists. Retroviral elements, ubiquitin, calmodulin, actin, and tubulin are only some of the many biological elements that are being investigated in yeast cells. Ras-related genes, strongly implicated in the transformation of normal mammalian to cancer cells, 2 have also been discovered in yeasts, opening the way for exciting new cytological, biochemical, and experimental genetic strategies that were impossible to carry out in animal cells. Cytoplasmic viruslike particles (VLPs) were first observed in diseased mushrooms. 3 Since then, viruses have been detected in more than 100 different fungal species. In most of these species, the persistent viral infection produces no discernible effect on the fungal host's phenotype. However, the finding that the antiviral and interferon-inducing activities of extracts (statolon, hellenin) from Penicillium species were due to the presence of double-stranded RNA (dsRNA) has sparked an explosion of interest in what has now become a new area for research in The hypovirulence of certain forms of Endothia parasitica, which may cause chestnut blight disease, has also been found to be related to the presence oflipid-rich cytoplasmic vesicles containing dsRNA. Reduction of cytochrome oxidase and respiratory deficiency resulting in abnormal growth and morphology have been linked to specific dsRNA segments in Ophiostoma ulmi (which causes Dutch elm disease). The biological properties of the dsRNA genomes that are in capsid form in noninfectious VLPs within the fungal cytoplasm have proved to be unique. These mycoviruses are apparently incapable of extracellular transmission through lysis of the host cell. They are