Changes in membrane fluidity modulate heat shock gene expression and produced attenuated strains in the dimorphic fungus Histoplasma capsulatum
Maresca, B.; Kobayashi, G.
Archives of Medical Research 24(3): 247-249
1993
ISSN/ISBN: 0188-4409 PMID: 8298273 Document Number: 409968
The addition (at 25 degrees C) of saturated fatty acid (palmitic acid) to H. capsulatum mycelia induced a significant increase in heat shock mRNA transcription when cells were heat shocked while treatments with unsaturated fatty acids (oleic acid) reduced the level of heat shock gene transcription at 37 degrees C. Addition of saturated fatty acid induced a thermotolerant state and mitochondria retained ATPase activity coupled to electron transport under severe heat shock conditions and shortened the time for mycelium-to-yeast phase transition. The addition of unsaturated fatty acids uncoupled mitochondrial electron transport and prolonged the time required for phase transition at the same temp. A virulent strain treated with unsaturated fatty acid under conditions in which no heat shock was detectable, lost its virulence as a consequence of decreased ability for adaptation.