Further, given that the reactivity of dissociated [HS.sup.-] is greater than that of [H.sub.2]S, it may be assumed that  (1) both the gas and anions coexist in vivo; (2) dissociated bisulphide is more reactive than [H.sub.2]S and peaks at pH 11 ; and (3) the presence of oxygen could diminish the reduction force.
In mammalian cells, [H.sub.2]S passes through the cell membrane and its salts pass through bisulphide channels, where they are exchanged for [Cl.sup.-] (by anion exchange protein AE1).
While [H.sub.2]S enters cells through the plasma membrane, [HS.sup.-] is released through bisulphide channels to the extracellular environment.
(1) Bisulphide ions favour the survival of granulocytes cultured in serum-free medium but not the survival of lymphocytes or eosinophils.
Aerobic bacteria initially catalyse the trio-oxidation of low grade refractory sulphide ores and naturally occurring sulphate reducing bacteria then convert the dissolved sulphates in the acid mine drainage into a dissolved bisulphide
leaching agent which is recirculated.