The appearances of autolytic and apoptotic markers are concomitant but differently regulated in carbon-starving Aspergillus nidulans cultures

In ageing, carbon-depleted cultures of Aspergillus nidulans strain FGSC 26 progressing apoptotic-type cell death was detected, characterised by increasing numbers of Annexin V and TUNEL stained cells after protoplastation. DAPI staining of autolysing mycelia revealed numerous nuclei with elongated, stick-like morphology, which was not observed in surviving hyphal fragments representing a cell population adapted to carbon starvation. Apoptotic cell death was also progressing in aging cultures of the non-autolysing loss-of-function fluG and ΔbrlA mutants, indicating that apoptotic cell death and autolysis were regulated independently. In accordance with this, sphingosine derivatives added to A. nidulans cultures increased cell death rates without influencing autolytic biomass losses and hydrolase production.