Strain 0206 of Cyanidium caldarium, a thermophilic acidophilic alga, is able to use nitrate as the sole nitrogen source. Usually the alga is grown in the laboratory in very acidic media. When nitrate is the nitrogen source, nitrite appears in the external medium. However, when the nitrite concentration in the medium reaches $15 \mu M$ it remains constant at this low level. When the alga is transferred to neutral pH, the nitrite concentration in the medium increases sharply. This increase is linear with time. This phenomenon constitutes an excellent method for measuring the reduction of nitrate to nitrite in vivo. The nitrite formation from nitrate is strongly inhibited by exogenously added ammonia.
Referenze Bibliografiche
[1] M. LOSADA (1976) - Metalloenzymes of the nitrate reducing system, «J. Mol. Catalysis», I, 245-264.
[2] A. G. MORTON (1956) - A study of nitrate reduction in mould fungi, «J. Exp. Botany», 7, 97-112.
[3] S. E. STEVENS e C. VAN BAALEN (1974) - Control of nitrate reductase in a blue-green alga. The effects of inhibitors, blue light, and ammonia, «Arch. Biochem. Biophys.», 161, 146-152.
[4] C. RIGANO, G. ALIOTTA e V. DI MARTINO RIGANO (1975) - Observations on enzymes of ammonia assimilation in two different strains of Cyanidium caldarium, «Arch. Microbiol.», 104, 297-299.
[5] C. RIGANO (1971) - Studies on nitrate reductase from Cyanidium caldarium, «Arch. Mikrobiol.», 76, 265-276.
[6] I. FUKUDA (1958) - Physiological studies on a thermophilic blue-green Cynidium caldarium, «Bot. Mag. Tokyo», 71, 79-86.
[7] W. N. DOEMEL e T. D. BROCK (1971) - The physiological ecology of Cyanidium caldarium, «J. Gen. Microbiol.», 67, 17-32.
[8] R. H. SCHLOEMER e R. H. GARRETT (1974) - Nitrate transport system in Neurospora crassa, «J. Bact.», 118, 259-269.
[9] C. RIGANO, G. ALIOTTA e U. VIOLANTE (1974) - Reversible inactivation by ammonia of assimilatory nitrate reductase in Cyanidium caldarium, 99, 81-90.
Con il contributo del Ministero per i Beni e le Attività Culturali