doiSerbia

Effect of long-term cyanide exposure on cyanide-sensitive respiration and phosphate metabolism in the fungus Phycomyces blakesleeanus

Stanić Marina (Institute for Multidisciplinary Research, Department of Life Sciences, Belgrade)
Živić M. (Faculty of Biology, Department of Physiology and Biophysics, Belgrade)
Hadžibrahimović Mirzeta (State University of Novi Pazar, Department of Biology, Novi Pazar)
Pajdić Aleksandra (Faculty of Biology, Department of Physiology and Biophysics, Belgrade)
Križak S. (Institute for Multidisciplinary Research, Department of Life Sciences, Belgrade)
Žižić M. (Institute for Multidisciplinary Research, Department of Life Sciences, Belgrade)
Zakrzewska Joanna (Institute of General and Physical Chemistry, NMR Laboratory, Belgrade)

The effects of long-term exposure (5 h) of Phycomyces blakesleeanus mycelium to 5 mM KCN on respiration and phosphate metabolites were tested. Exposure to cyanide, antimycin A and azide lead to a decrease in the activity of cyanide-sensitive respiration (CSR), and the ratio of core polyphosphates (PPc) and inorganic phosphates (Pi), which is a good indicator of the metabolic state of a cell. After 5 h of incubation, the activity of CSR returned to control values. For this, the recovery of cytochrome c oxidase (COX) was required. In addition, the PPc/Pi ratio started to recover shortly after initiation of COX recovery, but never reached control values. This led us to conclude that the regulation of polyphosphate (PPn) levels in the cell is tightly coupled to respiratory chain functioning. In addition, acutely applied cyanide caused two different responses, observed by 31P NMR spectroscopy, that were probably mediated through the mechanism of glycolytic oscillations, triggered by the effect of cyanide on mitochondria.

Keywords: Phycomyces blakesleeanus, cyanide sensitive respiration, polyphosphates, sugar phosphates, 31P NMR

Projekat Ministarstva nauke Republike Srbije, br. 173040