Strain-dependent effects of environmental signals on the production of extracellular phospholipase by Cryptococcus neoformans.
Extracellular phospholipase (PL) activities comprising phospholipase B, lysophospholipase and lysophospholipase transacylase have been identified in culture supernatants of Cryptococcus neoformans and contribute to virulence. We found that PL production was optimal after fungal growth at 30 degrees C and secretion at 37 degrees C for all six C. neoformans isolates studied (four C. neoformans var. neoformans and two C. neoformans var. gattii). No increase in PL activity was found in one strain, NU-2, in low iron or tissue culture media, conditions where upregulation of other virulence factors has been reported. The most virulent strains in an intravenous mouse model of infection were best able to produce PL at growth and secretion temperatures of 37 degrees C, in tissue culture media and under assay conditions of pH 7.0.
Wright
Lesley C
LC
Centre for Infectious Diseases and Microbiology, Level 3, ICPMR Building, Westmead Hospital, Darcy Rd., NSW, 2145, Australia. lesleyw@icpmr.wsahs.nsw.gov.au
Chen
Sharon C A
SC
Wilson
Christabel F
CF
Simpanya
Mukoma F
MF
Blackstock
Rebecca
R
Cox
Gary M
GM
Murphy
Juneann W
JW
Sorrell
Tania C
TC
D002021:Buffers; D003455:Cryptococcus neoformans / Q000201:enzymology* / Q000254:growth & development* / Q000472:pathogenicity; D003470:Culture Media / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005110:Extracellular Space; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000494:pharmacology; D010740:Phospholipases / Q000096:biosynthesis* / Q000378:metabolism; D015398:Signal Transduction; D013696:Temperature; D014774:Virulence
D002021:Buffers; D003470:Culture Media; D004791:Enzyme Inhibitors; D007093:Imidazoles; C029899:imidazole; D010740:Phospholipases; D005947:Glucose