The effect of azalomycin F on Ca2+ homeostasis in Trichoderma viride and Saccharomyces cerevisiae.
Azalomycin F (AMF), a macrocyclic lactone antibiotic, in concentrations of 10(-5) g/ml (10(-6) - 10(-5) mol/l) was found to stimulate both the 45Ca2+ influx and efflux in intact Trichoderma viride submerged mycelium and in cells of Saccharomyces cerevisiae without having Ca2+ ionophoric properties. AMF also inhibited ATP-dependent Ca2+ uptake in membrane fractions prepared from T. viride submerged mycelium. 45Ca2+ which had been accumulated in membrane fractions in an ATP-dependent manner was released upon addition of AMF. This release was observed in light organellar fractions (LOF) of S. cerevisiae and of T. viride submerged mycelium and, to a small extent, in heavy organellar fraction (HOF) of S. cerevisiae. No Ca2+ releasing effect of AMF was observed in HOF from T. viride submerged mycelium. In S. cerevisiae expressing Ca2+-dependent photoprotein aequorin, AMF induced transients of luminescence which reflect changes in the cytoplasmic Ca2+ concentration. The results suggest that the stimulation by AMF of the Ca2+ efflux from the mycelium (cells) could be explained by an increase of the cytoplasmic Ca2+ concentration due to the release of Ca2+ from microsomal membranes or to the stimulation of Ca2+ influx.
Simkovic
M
M
Department of Biochemistry and Microbiology, Slovak University of Technology, Bratislava.
Lakatos
B
B
Tsuji
F I
FI
Muto
S
S
Varecka
L
L
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002458:Cell Fractionation; D004533:Egtazic Acid / Q000494:pharmacology; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D018942:Macrolides; D015388:Organelles / Q000187:drug effects / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000502:physiology; D013347:Subcellular Fractions / Q000378:metabolism; D014242:Trichoderma / Q000187:drug effects* / Q000502:physiology
D000900:Anti-Bacterial Agents; D018942:Macrolides; C000232:azalomycin-F; D004533:Egtazic Acid; D002118:Calcium