scholarly journals Interactions between potassium ions and glycine transport in the yeast Saccharomyces carlsbergensis

1970 ◽  
Vol 120 (4) ◽  
pp. 845-852 ◽  
Author(s):  
A. A. Eddy ◽  
K. J. Indge ◽  
K. Backen ◽  
J. A. Nowacki
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Initial Rate ◽  
Competitive Inhibitor ◽  
Yeast Cells ◽  
Potassium Ions ◽  
Acid Transport ◽  
Saccharomyces Carlsbergensis ◽  
Glycine Transport

A study has been made of the effects of both varying the pH and extracellular [K+] on the initial rate of uptake of glycine (v) by a strain of Saccharomyces carlsbergensis that concentrated the amino acid, with respect to the extracellular phase, by up to 1400 times. When no other substrate than glycine was provided and [glycine] was relatively small (≤0.2mm) (1) v increased fivefold when the pH was lowered from 7 to 4.5; (2) v fell by up to about 80% as [K+] rose, K+ behaving as a non-competitive inhibitor of the system, with Ki 0.33mequiv./l at pH7; (3) the absorption of glycine caused up to about 2 or 3 equiv. of K+ to leave the yeast cells. These three phenomena were each less evident when glucose was present. An analogy is drawn between the respective interactions of H+ and K+ with the yeast system and the well recognized effects of Na+ and K+ on amino acid transport in certain mammalian systems.

AMINO ACID TRANSPORT IN YEAST AND EFFECTS OF NYSTATIN

1963 ◽  
Vol 41 (1) ◽  
pp. 397-407 ◽  
Author(s):  
E. Stachiewicz ◽  
J. H. Quastel
Keyword(s):  
Fatty Acids ◽  
Amino Acid ◽  
Calcium Ions ◽  
Amino Acid Transport ◽  
Protective Action ◽  
Yeast Cells ◽  
Acid Transport ◽  
Free Medium ◽  
Complete Protection ◽  
Normal Cells

Nystatin, an antifungal antibiotic, inhibits the accumulation, by yeast cells, of glycine, leucine, arginine, and alanine at concentrations that have no effect on the respiration of the cells. The uptake of glycine by yeast cells that have been preincubated with nystatin and then suspended in a nystatin-free medium is much lower than that of normal cells. The longer the preincubation with nystatin, the greater is the inhibition of glycine uptake. Nystatin produces two distinct effects. At concentrations below 0.8 μg/ml, nystatin inhibits glycine or arginine uptake. At concentrations from 0.8 to 2.0 μg/ml, it causes an efflux of previously accumulated glycine or arginine. Fatty acids, such as oleic, linoleic, stearic, or palmitic acid, can protect the yeast cell from the action of nystatin. The presence of citrate or versene abolishes the protective action of these fatty acids. Calcium ions also protect the cell from the action of nystatin. The concentration of calcium ions giving complete protection depends upon the nystatin concentration. The implications of these facts on amino acid transport in yeast are discussed.

Alterations in membrane permeability with trypsin treatment

1981 ◽  
Vol 59 (8) ◽  
pp. 668-675 ◽  
Author(s):  
P. A. Johnson ◽  
R. M. Johnstone
Keyword(s):  
Amino Acid ◽  
Membrane Permeability ◽  
Amino Acid Transport ◽  
Acid Transport ◽  
Transport Activity ◽  
Trypsin Treatment ◽  
Trypsin Inhibition ◽  
Active Amino Acid ◽  
Glycine Transport ◽  
Normal Transport

Trypsin treatment of Ehrlich cells reduced sodium-coupled amino acid transport, lowered ATP levels, and abolished cation gradients. The data suggest that the decrease in active amino acid transport results from an alteration in membrane permeability caused by DNA released from a fraction of the cells upon trypsin treatment. The reduced amino acid transport appears to be the result of an abolition of ion gradients required for transport since vesicles prepared from these cells show near normal transport activity. The altered permeability of the membrane can be restored by incubation of the cells with serum. Protein synthesis does not appear to play a role in the restoration of Na+-dependent amino acid transport since restoration is unaffected by the presence of cycloheximide. The recovery of activity does depend partly on the presence of Ca2+ in the incubation medium since reversal of the trypsin inhibition of glycine transport can be obtained on incubation with Ca2+ and glucose.

AMINO ACID TRANSPORT IN YEAST AND EFFECTS OF NYSTATIN

1963 ◽  
Vol 41 (2) ◽  
pp. 397-407 ◽  
Author(s):  
E. Stachiewicz ◽  
J. H. Quastel
Keyword(s):  
Fatty Acids ◽  
Amino Acid ◽  
Calcium Ions ◽  
Amino Acid Transport ◽  
Protective Action ◽  
Yeast Cells ◽  
Acid Transport ◽  
Free Medium ◽  
Complete Protection ◽  
Normal Cells

Nystatin, an antifungal antibiotic, inhibits the accumulation, by yeast cells, of glycine, leucine, arginine, and alanine at concentrations that have no effect on the respiration of the cells. The uptake of glycine by yeast cells that have been preincubated with nystatin and then suspended in a nystatin-free medium is much lower than that of normal cells. The longer the preincubation with nystatin, the greater is the inhibition of glycine uptake. Nystatin produces two distinct effects. At concentrations below 0.8 μg/ml, nystatin inhibits glycine or arginine uptake. At concentrations from 0.8 to 2.0 μg/ml, it causes an efflux of previously accumulated glycine or arginine. Fatty acids, such as oleic, linoleic, stearic, or palmitic acid, can protect the yeast cell from the action of nystatin. The presence of citrate or versene abolishes the protective action of these fatty acids. Calcium ions also protect the cell from the action of nystatin. The concentration of calcium ions giving complete protection depends upon the nystatin concentration. The implications of these facts on amino acid transport in yeast are discussed.

scholarly journals Activity-dependent Reversible Inactivation of the General Amino Acid Permease

2006 ◽  
Vol 17 (10) ◽  
pp. 4411-4419 ◽  
Author(s):  
April L. Risinger ◽  
Natalie E. Cain ◽  
Esther J. Chen ◽  
Chris A. Kaiser
Keyword(s):  
Amino Acids ◽  
Plasma Membrane ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Yeast Cells ◽  
Single Amino Acid ◽  
Acid Transport ◽  
Amino Acid Permease ◽  
Reversible Inactivation ◽  
General Amino Acid Permease

The general amino acid permease, Gap1p, of Saccharomyces cerevisiae transports all naturally occurring amino acids into yeast cells for use as a nitrogen source. Previous studies have shown that a nonubiquitinateable form of the permease, Gap1pK9R,K16R, is constitutively localized to the plasma membrane. Here, we report that amino acid transport activity of Gap1pK9R,K16Rcan be rapidly and reversibly inactivated at the plasma membrane by the presence of amino acid mixtures. Surprisingly, we also find that addition of most single amino acids is lethal to Gap1pK9R,K16R-expressing cells, whereas mixtures of amino acids are less toxic. This toxicity appears to be the consequence of uptake of unusually large quantities of a single amino acid. Exploiting this toxicity, we isolated gap1 alleles deficient in transport of a subset of amino acids. Using these mutations, we show that Gap1p inactivation at the plasma membrane does not depend on the presence of either extracellular or intracellular amino acids, but does require active amino acid transport by Gap1p. Together, our findings uncover a new mechanism for inhibition of permease activity in response to elevated amino acid levels and provide a physiological explanation for the stringent regulation of Gap1p activity in response to amino acids.

Placental Amino Acid transport is decreased after exposure to hypoxia

2008 ◽  
Vol 68 (S 01) ◽  
Author(s):  
FM von Versen-Höynck ◽  
A Rajakumar ◽  
JM Roberts ◽  
W Rath ◽  
RW Powers
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Acid Transport

scholarly journals Induction of amino acid transport in primary cultures of adult rat liver parenchymal cells by insulin.

1976 ◽  
Vol 251 (10) ◽  
pp. 3014-3020 ◽  
Author(s):  
R F Kletzien ◽  
M W Pariza ◽  
J E Becker ◽  
V R Potter ◽  
F R Butcher
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Amino Acid Transport ◽  
Primary Cultures ◽  
Acid Transport ◽  
Liver Parenchymal ◽  
Adult Rat ◽  
Parenchymal Cells
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