title: Use of Ion-Channel Modulating Agents to Study Cyanobacterial Na(+) - K(+) Fluxes.
abstract: Here we describe an experimental design aimed to investigate changes in total cellular levels of Na(+) and K(+) ions in cultures of freshwater filamentous cyanobacteria. Ion concentrations were measured in whole cells by flame photometry. Cellular Na(+) levels increased exponentially with rising alkalinity, with K(+) levels being maximal for optimal growth pH (~8). At standardized pH conditions, the increase in cellular Na(+), as induced by NaCl at 10 mM, was coupled by the two sodium channel-modulating agents lidocaine hydrochloride at 1 microM and veratridine at 100 microM. Both the channel-blockers amiloride (1 mM) and saxitoxin (1 microM), decreased cell-bound Na(+) and K(+) levels. Results presented demonstrate the robustness of well-defined channel blockers and channel-activators in the study of cyanobacterial Na(+)- K(+) fluxes.
authors.affiliation: Cyanobacteria and Astrobiology Research Laboratory, School of Biotechnology and Biomolecular Sciences, The University of New South Wales. Sydney 2052, NSW. Australia.
authors.forename: Francesco
authors.initials: F
authors.lastname: Pomati
authors.forename: Brendan P.
authors.initials: BP
authors.lastname: Burns
authors.forename: Brett A.
authors.initials: BA
authors.lastname: Neilan