Stoichiometry between CO/sub 2/ and H/sup +/ fluxes involved involved in the transport of inorganic carbon in cyanobacteria. [Anacystis nudlans]

Journal Article · Wed Apr 01 00:00:00 EST 1987 · Plant Physiol.; (United States)

OSTI ID:6021219

Ogawa, T; Kaplan, A

The pH of the medium during CO/sub 2/ uptake into the intracellular inorganic carbon (C/sub i/) pool of a high CO/sub 2/-requiring mutant (E/sub 4/) and wild type of Anacystis nidulans R2 was measured. Experiments were performed under conditions where photosynthetic CO/sub 2/ fixation is inhibited. There was an acidification of the medium during CO/sub 2/ uptake in the light and an alkalization during CO/sub 2/ efflux after darkening. A one to one stoichiometry existed between the amounts of H/sup +/ appearing in the medium and CO/sub 2/ taken up into the intracellular C/sub i/ pool, regardless of the carbon species transported. The results indicate that (a) CO/sub 2/ is taken up simultaneously with an efflux of equimolar H/sup +/, probably produced as a result of CO/sub 2/ hydration during transport and (b) HCO/sub 3//sup -/ produced by hydration of CO/sub 2/ in the medium was transported into the cells without accompanying net flux of H/sup +/ or OH/sup -/. The influx and efflux of C/sub i/ during C/sub i/ transport produced nonequilibrium between CO/sub 2/ and HCO/sub 3//sup -/ in the medium, with the concentration of HCO/sub 3//sup -/ being higher than that expected under equilibrium conditions. The nonequilibrium was present even under the conditions where the influx of C/sub i/ is compensated by its efflux. The direction of this nonequilibrium suggested that efflux of HCO/sub 3//sup -/ occurs during uptake of C/sub i/.

• Research Organization: Institute of Physical and Chemical Research (RIKEN), Saitama, Japan
• OSTI ID: 6021219
• Journal Information: Plant Physiol.; (United States), Vol. 83:4
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ACID CARBONATES
STOICHIOMETRY
CARBON
MEMBRANE TRANSPORT
CARBON DIOXIDE
HYDROGEN IONS 1 PLUS
CARBON DIOXIDE FIXATION
DYNAMIC FUNCTION STUDIES
EQUILIBRIUM
MUTANTS
PARTITION
PH VALUE
PHOTOSYNTHETIC BACTERIA
PHYSIOLOGY
CARBON COMPOUNDS
CARBON OXIDES
CATIONS
CHALCOGENIDES
CHARGED PARTICLES
ELEMENTS
HYDROGEN IONS
IONS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
551000* - Physiological Systems