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NMR studies on Na+ transport in Synechococcus PCC 6311
External Online Source: doi:10.1016/0003-9861(92)90694-R
Author and Affiliation:
Nitschmann, W. H.(University of California 94720, Lawrence Berkeley Laboratory, Department of Molecular and Cell Biology)
Packer, L.
Abstract: The freshwater cyanobacterium Synechococcus PCC 6311 is able to adapt to grow after sudden exposure to salt (NaCl) stress. We have investigated the mechanism of Na+ transport in these cells during adaptation to high salinity. Na+ influx under dark aerobic conditions occurred independently of delta pH or delta psi across the cytoplasmic membrane, ATPase activity, and respiratory electron transport. These findings are consistent with the existence of Na+/monovalent anion cotransport or simultaneous Na+/H+ +anion/OH- exchange. Na+ influx was dependent on Cl-, Br-, NO3-, or NO2-. No Na+ uptake occurred after addition of NaI, NaHCO3, or Na2SO4. Na+ extrusion was absolutely dependent on delta pH and on an ATPase activity and/or on respiratory electron transport. This indicates that Na+ extrusion via Na+/H+ exchange is driven by primary H+ pumps in the cytoplasmic membrane. Cells grown for 4 days in 0.5 m NaCl medium, "salt-grown cells," differ from control cells by a lower maximum velocity of Na+ influx and by lower steady-state ratios of [Na+]in/[Na+]out. These results indicate that cells grown in high-salt medium increase their capacity to extrude Na+. During salt adaptation Na+ extrusion driven by respiratory electron transport increased from about 15 to 50%.
Publication Date: May 01, 1992
Document ID:
20040112289
(Acquired Oct 05, 2004)
Subject Category: LIFE SCIENCES (GENERAL)
Document Type: Journal Article
Publication Information: Archives of biochemistry and biophysics (ISSN 0003-9861); Volume 294; 2; 347-52
Publisher Information: United States
Description: In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: BACTERIA; NUCLEAR MAGNETIC RESONANCE; SODIUM; SODIUM CHLORIDES; ADENOSINETRIPHOSPHATASE; CELL MEMBRANES (BIOLOGY); CLOSED ECOLOGICAL SYSTEMS; CULTURE MEDIA; ELECTRON TRANSFER; ION CONCENTRATION; ION MOTION; LIFE SUPPORT SYSTEMS; MAGNETIC RESONANCE SPECTROSCOPY; TIME DEPENDENCE
Other Descriptors: BIOLOGICAL TRANSPORT, ACTIVE; PROTON PUMPS/METABOLISM; SODIUM/PHARMACOKINETICS; SODIUM CHLORIDE/PHARMACOLOGY; SYNECHOCOCCUS GROUP/GROWTH & DEVELOPMENT/METABOLISM; ADENOSINETRIPHOSPHATASE/METABOLISM; CELL MEMBRANE PERMEABILITY; CULTURE MEDIA; ELECTRON TRANSPORT/PHYSIOLOGY; HYDROGEN-ION CONCENTRATION; ION TRANSPORT; MAGNETIC RESONANCE SPECTROSCOPY; SUPPORT, U.S. GOV'T, NON-P.H.S; TIME FACTORS; NASA DISCIPLINE LIFE SUPPORT SYSTEMS; NASA DISCIPLINE NUMBER 61-10; NASA PROGRAM CELSS; NON-NASA CENTER
Availability Source: Other Sources
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