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.

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 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.

scholarly journals Dietary ω 3 fatty acid alters prostaglandin synthesis, glucose transport and protein turnover in skeletal muscle of healthy and diabetic rats

1992 ◽  
Vol 286 (2) ◽  
pp. 405-411 ◽  
Author(s):  
P S Sohal ◽  
V E Baracos ◽  
M T Clandinin
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Amino Acid ◽  
Glucose Transport ◽  
Amino Acid Transport ◽  
Protein Turnover ◽  
Diabetic Rats ◽  
Omega 3 Fatty Acids ◽  
Acid Transport ◽  
Omega 3

The present study was designed to determine if dietary-fat-induced alterations in the fatty acid composition of skeletal-muscle lipid alters insulin-dependent and basal muscle metabolism, including glucose and amino acid transport, prostaglandin (PG) synthesis and protein turnover. Rats were fed on high-fat semi-purified diets providing 19% or 1% omega 3 fatty acids in the form of fish oil, for 6 weeks. After 3 weeks, half of the rats were made diabetic by a single injection of streptozotocin (50 mg/kg body wt.). After a further 3 weeks, contralateral epitrochlearis and extensor digitorum longus (EDL) muscles from each rat were incubated in vitro. High levels of dietary omega 3 fatty acids decreased PGE2 and PGF2 alpha synthesis in EDL and epitrochlearis muscle (P less than 0.0001). Diabetes and insulin had no effect on PG synthesis. Diet did not alter basal glucose or amino acid transport in EDL muscle from healthy or diabetic rats. Insulin increased glucose and amino acid transport (P less than 0.0001); the increase in glucose transport by insulin was significantly greater in muscles of rats fed on high levels of omega 3 fatty acids (P less than 0.05). Epitrochlearis from rats fed on high levels of omega 3 fatty acids showed decreased net protein degradation in the presence and absence of insulin, owing to decreased rates of protein degradation and synthesis. The data suggest that high levels of dietary omega 3 fatty acids that alter muscle membrane composition also result in alterations in glucose transport and the metabolism of muscle protein.

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.

Species differences in the response of amino acid transport to ouabain and a sodium-free medium

1966 ◽  
Vol 18 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Henry J. Binder ◽  
Marigrace Boyer ◽  
Howard M. Spiro ◽  
Richard P. Spencer
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Species Differences ◽  
Acid Transport ◽  
Free Medium

scholarly journals Differential regulation of placental amino acid transport by saturated and unsaturated fatty acids

2014 ◽  
Vol 307 (8) ◽  
pp. C738-C744 ◽  
Author(s):  
Susanne Lager ◽  
Thomas Jansson ◽  
Theresa L. Powell
Keyword(s):  
Fatty Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Unsaturated Fatty Acids ◽  
Cellular Signaling ◽  
Dietary Fatty Acids ◽  
Initiation Factor ◽  
Acid Transport ◽  
Placental Function ◽  
Eukaryotic Initiation Factor 4E

Fatty acids are critical for normal fetal development but may also influence placental function. We have previously reported that oleic acid (OA) stimulates amino acid transport in primary human trophoblasts (PHTs). In other tissues, saturated and unsaturated fatty acids have distinct effects on cellular signaling, for instance, palmitic acid (PA) but not OA reduces IκBα expression. We hypothesized that saturated and unsaturated fatty acids differentially affect trophoblast amino acid transport and cellular signaling. To test this hypothesis, PHTs were cultured in docosahexaenoic acid (DHA; 50 μM), OA (100 μM), or PA (100 μM). DHA and OA were also combined to test whether DHA could counteract the OA stimulatory effect on amino acid transport. The effects of fatty acids were compared against a vehicle control. Amino acid transport was measured by isotope-labeled tracers. Activation of inflammatory-related signaling pathways and the mechanistic target of rapamycin (mTOR) pathway were determined by Western blot analysis. Exposure of PHTs to DHA for 24 h reduced amino acid transport and phosphorylation of p38 MAPK, STAT3, mTOR, eukaryotic initiation factor 4E-binding protein 1, and ribosomal protein (rp)S6. In contrast, OA increased amino acid transport and phosphorylation of ERK, mTOR, S6 kinase 1, and rpS6. The combination of DHA with OA increased amino acid transport and rpS6 phosphorylation. PA did not affect amino acid transport but reduced IκBα expression. In conclusion, these fatty acids differentially regulated placental amino acid transport and cellular signaling. Taken together, these findings suggest that dietary fatty acids could alter the intrauterine environment by modifying placental function, thereby having long-lasting effects on the developing fetus.

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
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