Dunaliella acidophila (Kalina) Masyuk — an alga with a positive membrane potential

Life at acidic pH imposes an increased energetic cost for a eukaryotic acidophile

“…maintains a mean cytosolic pH of 6.6 in extracellular medium of pH·2.0, so it is 3.2 times more acidic than C. reinhardtii, which maintains a mean cytosolic pH of 7.1 in an extracellular pH·7.0. The neutral cytosolic pH is similar to other acidophilic algae like Cyanidium caldarium (Beardall and Entwisle, 1984;Enami et al, 1986) and Dunaliella acidophilum (Gimmler et al, 1989). The cytosolic pH of the acidophile does not change dramatically between extracellular medium at pH·2 or pH·7.…”

“…There are conflicting reports of the cytosolic pH from acidophiles. Cyanidium caldarium (Beardall and Entwisle, 1984;Enami et al, 1986) and Dunaliella acidophilum (Gimmler et al, 1989), grown at extracellular pH of 2.1 and 0-1.0, respectively, maintain cytosolic pH of 6.6 and 7.0, respectively. In contrast, Picrophilus oshimae (van de Vossenburg et al, 1998), Bacillus acidocaldarius (Thomas et al, 1976), Sarcina ventriculi (Goodwin and Zeikus, 1987) and Euglena mutabilis (Lane and Burris, 1981) grown at pH·0.8-4.0, 3.0, 3.0 and 2.8, respectively, are reported to maintain acidic cytosolic pH of 4.6, 5.5, 4.25 and 5.0-6.4, respectively.…”

Purification and Properties of a Plasma Membrane H+-ATPase from the Extremely Acidophilic Alga Dunaliella acidophila

“…Recently, we isolated a plasma membrane fraction from Dunaliella acidophila, an extremely acidophilic strain of the unicellular green alga Dunaliella (Sekler et al, 1991). This organism grows optimally at pH 1 and maintains an intracellular pH of 7 (Albertano et al, 1982;Gimmler et al, 1989b). The membrane preparation possesses a highly active vanadate-sensitive ATPase activity, suggesting that the plasma membrane H+-ATPase is expressed at high density in this alga (Sekler et al, 1991).…”

Physiological Responses of Non-Vascular Plants to Heavy Metals

“…This suggests that species occurring in these acidic situations may be co-tolerant to metals. Gimmler et al (1989Gimmler et al ( , 1991 have verified the above hypothesis with the help of the unicellular acid resistant green alga Dunaliella acidaphila. This alga exhibits optimal growth and photosynthesis at a pH of 1.0.…”