Hydrogen sulphide - both toxicant and a cell signalling molecule

Perjantai 13.10.2017 klo 11.53 - Mikko Nikinmaa

With increased eutrophication many aquatic bodies have anoxic bottom sediments. They are characterized by high concentration of hydrogen sulphide, smelling of rotten eggs. Hydrogen sulphide is considered to be a highly toxic substance, and together with the lack of oxygen contributing to the death of organisms in the hypoxic areas. This may be so, but the initial effects disturbing the functions of organisms may not be caused by the traditionally considered effect of sulphide disturbing aerobic respiration.

It has recently become clear that hydrogen sulphide is an important cellular signalling molecule, in various cases the "oxygen sensor" of the cells. Thus, variations in its cellular concentrations fine-tune oxygen-dependent effects tp occur appropriately. Consequently, any disturbances in the level of hydrogen sulphide can disturb cellular signalling, and harmful effects can take place because of disturbances of cell signalling even when the concentration would not be adequate to cause breakdown of aerobic respiration and death because of that.