Cu2+ efflux and its regulation in Cu‐resistant (Cur) cyanobacterium Nostoc calcicola BRÉB

摘要: Cu2+-tolerant/resistant (Cur) strain of the cyanobacterium Nostoc calcicola BREB., developed in laboratory, showed remarkable growth ambient medium containing 40 μM Cu2+ (5 being lethal for wild type strain). It 22% less uptake compared to Cus (Cu-sensitive) cells. Cur cyanobacterial cells were characterized by a time-dependent efflux contrast no cation pattern consisted two distinct phases: First rapid (10 min) followed slower second one at least up 1 h. depended major extent on light generated ATP1), as dark exposed 87% reduction efflux. The lowering presence various metabolic inhibitors/uncouplers like carbonyl cyanide-m-chloro phenyl hydrazone (CCCP)1), N,N'-dicyclohexycarbodiimide (DCCD), azide (NaN3) and p-chloromercuribenzoate (pCMB) indicated involvement -SH group, membrane potential ATP hydrolysis regulation this process. was also initiated such 100-fold lower concentration (0.4 μM) (saturing metal uptake) not before. is suggested that N. may be predominant mechanism resistance/tolerance organism are regulated different levels modifying factors.