Proton gradients in intact cyanobacteria. [Gleobacter violaceus; Agmenellum quadruplicatum]

Journal Article · Fri May 01 00:00:00 EDT 1987 · Plant Physiol.; (United States)

OSTI ID:6066368

Belkin, S; Mehlhorn, R J; Packer, L

The internal pH values of two unicellular cyanobacterial strains were determined with electron spin resonance probes, over an external pH range of 6 to 9, in the light and in the dark. The slow growing, thylakoid-lacking Gloeobacter violaceus was found to have a low capacity for maintaining a constant internal pH. The distribution pattern of weak acid and amine nitroxide spin probes across the cell membranes of this organism, in the light and in the dark, was consistent with the assumption that it contains a single intercellular compartment. At an external pH of 7.0, intracellular pH was 6.8 in the dark and 7.2 in the light. The cells of Agmenellum quadruplicatum, a marine species, were found to contain two separate compartments; in the dark, the pH of the cytoplasmic and the intrathylakoid spaces were calculated to be 7.2 and 5.5, respectively. Upon illumination, the former increased and the latter decreased by about 0.5 pH units.

• Research Organization: Lawrence Berkeley Lab., CA
• DOE Contract Number: AS03-80ER10637; AC03-76SF00098
• OSTI ID: 6066368
• Journal Information: Plant Physiol.; (United States), Vol. 84:1
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CELL MEMBRANES
ELECTRIC POTENTIAL
PHOTOSYNTHETIC BACTERIA
PROTON DENSITY
BIOLOGICAL RADIATION EFFECTS
ELECTRON SPIN RESONANCE
MEMBRANE TRANSPORT
PARTITION
PERMEABILITY
PH VALUE
PHYSIOLOGY
BIOLOGICAL EFFECTS
CELL CONSTITUENTS
MAGNETIC RESONANCE
MEMBRANES
RADIATION EFFECTS
RESONANCE
551000* - Physiological Systems