Mitochondria under hypoxia

Mitochondrial behaviour under low oxygen stress is important in programmed cell death signalling under low oxygen conditions. This is being studied in the wheat seedlings (roots) and protoplasts and in Arabidopsis transformants that have an extra hemoglobin gene (Vitreoscilla haemoglobin), which may protect the plants from oxygen depletion.

To follow the onset or programmed cell death, Ca2+ signaling has been studied in wheat root protoplasts with confocal laser scanning microscope with Ca2+ sensitive fluorescent dyes and with mitochondrial specific dyes. This has been done in order to follow mitochondrial actions due to loss of their membrane potential, probable opening of the permeability transition pore and release of proapoptotic signals (e.g. cytochrome c) under oxygen deprivation stress.

In connection with this we are also studying the role of the mitochondrial ATPase inhibitor protein IF1. This inhibitor has a probable role in the inhibition of ATPase activity in mitochondria under adverse environmental conditions and its affinity to ATPase may differ in plants which have adapted to stress conditions. We have acquired an antibody against the IF1-protein from a Japanese research group and we are using this to detect the affinity of IF1 protein to the ATPase during normal aerobic and low oxygen conditions.