Biomaterial Database

Membrane transport in an osmotically fragile mutant of Saccharomyces cerevisiae. 1988

A Kotyk, and P Venkov, and M Dvoráková

Institute of Physiology, Czechoslovak Academy of Sciences, Prague.

Transport properties of the osmotically fragile strain VY1160 of Saccharomyces cerevisiae were compared with those of the parent S288c strain. Mediated diffusion of 6-deoxy-D-glucose was practically unaffected; membrane-potential-dependent transport of D-glucosamine was very much depressed in the fragile strain. The H+-driven transport of L-lysine and L-proline, as well as that of the hitherto uninvestigated D-glucose-6-phosphate, were also very depressed. 2-Deoxy-D-glucose transport displayed slightly different kinetic parameters. Primary H+ extrusion by the plasma membrane H-ATPase was not diminished although the ATP-splitting activity was depressed by about 50%. The overall proton-motive force (pmf) of the fragile mutant at pH 5.5 was only 20 mV while in the parent strain it was 108 mV. In parallel with this, spontaneous acidification of the external medium (a CO2-associated event) was only about 2% of that in the parent strain. The defect in this, together with the inability to stimulate transport protein synthesis by glucose, may account for the generally poorer transport performance of the fragile mutant.

UI	MeSH Term	Description	Entries
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009996	Osmotic Fragility	RED BLOOD CELL sensitivity to change in OSMOTIC PRESSURE. When exposed to a hypotonic concentration of sodium in a solution, red cells take in more water, swell until the capacity of the cell membrane is exceeded, and burst.	Saline Fragility,Fragility, Osmotic,Fragility, Saline
D011522	Protons	Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.	Hydrogen Ions,Hydrogen Ion,Ion, Hydrogen,Ions, Hydrogen,Proton
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D002473	Cell Wall	The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.	Cell Walls,Wall, Cell,Walls, Cell
D003847	Deoxyglucose	2-Deoxy-D-arabino-hexose. An antimetabolite of glucose with antiviral activity.	2-Deoxy-D-glucose,2-Deoxyglucose,2-Desoxy-D-glucose,2 Deoxy D glucose,2 Deoxyglucose,2 Desoxy D glucose
D004058	Diffusion	The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.	Diffusions
D004187	Disaccharides	Oligosaccharides containing two monosaccharide units linked by a glycosidic bond.	Disaccharide
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations