A Comparison of Potassium and Chloride Uptake by Tradescantia albiflora Leaf Cells at Different KCI Concentrations

1975 ◽  
Vol 2 (4) ◽  
pp. 471
Author(s):  
C Johansen ◽  
U Luttge
Keyword(s):  
Oxidative Phosphorylation ◽  
Ion Uptake ◽  
Metabolic Inhibitors ◽  
K Uptake ◽  
Chloride Uptake ◽  
Cyclic Photophosphorylation

Light stimulates K+ and Cl- uptake into T. albiflora leaf slices from solutions through which N*2 is bubbled, and not from aerated solutions, at KCl concentrations of 0.5, 5 and 20 mM. The metabolic inhibitors CCCP, DCMU and oligomycin affect K+ and Cl- uptake similarly at each of these KCl concentrations. The results suggest that both K+ and Cl- uptake under all conditions studied are driven by energy derived from a cytoplasmic pool of ATP. In aerobic solutions in the light ATP can be supplied by either oxidative phosphorylation or photophosphorylation while in N*2-bubbled solutions in the light non-cyclic photophosphorylation and possibly oxidative phosphorylation, utilizing photosynthetically evolved O*2, provide ATP. As Cl- uptake appears to be independent of K+ uptake, it is suggested that ion uptake by T. albiflora leaf cells may occur according to a mechanism which has been proposed for other green cells, where K+ and CI- are thought to exchange for H+ and OH- respectively.

scholarly journals A Comparison of the Effects of Metabolic Inhibitors on Chloride Uptake and Photosynthesis In Chara Oorallina

1969 ◽  
Vol 22 (2) ◽  
pp. 351 ◽  
Author(s):  
FA Smith ◽  
KR West
Keyword(s):  
Comparative Study ◽  
Electron Flow ◽  
External Solution ◽  
Metabolic Inhibitors ◽  
Chloride Uptake ◽  
Low Concentrations ◽  
Carbonyl Cyanide ◽  
Chloride Influx

A comparative study has been made of the effects of four metabolic inhibitors on chloride uptake and photosynthetic 14C02 fixation by cells of O. corallina, and on oxygen evolution by chloropl<1sts isolated from the cells. Low concentrations of phlorizin and Dio-9 inhibited chloride uptake, but this was not accompanied by an inhibition of photosynthesis in vivo, and could not be correlated with the measured inhibition of electron flow in vitro. Low concentrations of imidazole stimulated the chloride influx in light, but there was again no effect on photosynthetic 14C02 fixation, although imidazole did uncouple electron flow in vitro. The effect of imidazole was dependent on the pH of the external solution. Increasing concentrations of carbonyl cyanide m-chlorophenylhydrazone progressively reduced the chloride influx and 14C02 fixation, and uncoupled electron flow in vitro. The work provides no evidence to support the view that chloride uptake is directly linked to electron flow rather than phosphorylation.

Relationships of Adenine Nucleotide Metabolism to Platelet-Collagen Adhesion

1978 ◽  
Vol 39 (02) ◽  
pp. 366-378 ◽  
Author(s):  
Robert J Morin ◽  
Albert F T Chen
Keyword(s):  
Oxidative Phosphorylation ◽  
Major Part ◽  
Adenine Nucleotide ◽  
Nucleotide Metabolism ◽  
Collagen Fibrils ◽  
Metabolic Inhibitors ◽  
Adenine Nucleotide Metabolism ◽  
Energy Dependent ◽  
Adhesion Of Platelets ◽  
Adhesion Process

SummaryAdhesion of platelets to collagen fibrils in a stirred system was inhibited by preincubation of platelets with combinations of 2-deoxy-D-glucose and oligomycin or antimycin. The inhibition of adhesion was associated with a decrease in metabolic ATP to 6% of control levels. Without metabolic inhibitors, platelets adherent to collagen fibrils were found to have catabolized approximately 57% of their metabolic ATP, and converted a major part of this to IMP. Storage pool ATP and ADP contents were also diminished in the adherent platelets. Pretreatment with imipramine resulted in 76% inhibition of the release reaction, but only 5% inhibition of adhesion. Imipramine-treated platelets that were adherent to collagen showed significant depletion of metabolic ATP, but markedly diminished conversion of ATP to IMP as compared to control adherent platelets. Inhibition of deamination of platelet AMP by coformycin or erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) did not inhibit adhesion, although platelets adherent to collagen after treatment with these agents showed depletion of metabolic ATP. These studies suggest that adhesion is an energy dependent process, occurring independently of release, and not associated with conversion of ATP to IMP. The energy dependent portions of the adhesion process are probably disc to sphere transformation and pseudopod formation, the ATP threshold requirement is relatively low, and the ATP utilized can probably be regenerated during the adhesion process via glycolysis and oxidative phosphorylation.

Activation of furosemide-sensitive K+ fluxes in myocytes by ouabain and recovery from metabolic inhibition

1990 ◽  
Vol 259 (3) ◽  
pp. H962-H972 ◽  
Author(s):  
O. Kohmoto ◽  
J. A. Krueger ◽  
W. H. Barry
Keyword(s):  
Calcium Concentration ◽  
Metabolic Inhibition ◽  
Atp Depletion ◽  
Metabolic Inhibitors ◽  
Cell Shrinkage ◽  
K Uptake ◽  
Dependent Protein Kinase ◽  
K Channels ◽  
Ventricular Cells ◽  
Dependent Protein

Modulation of transsarcolemmal K+ flux mediated by the furosemide-sensitive K(+)-Cl- (or Na(+)-K(+)-Cl-) cotransport carrier was studied in cultured chick embryo ventricular cells. We defined at least three distinct K+ efflux pathways: 1) a Ba2(+)-sensitive efflux component, probably reflecting K+ movement through K+ channels; 2) a furosemide-sensitive component, reflecting K(+)-Cl- cotransport; and 3) a component insensitive to both Ba2+ and furosemide. With respect to K+ influx, there were 1) a ouabain-sensitive K+ uptake presumably mediated by Na(+)-K(+)-adenosinetriphosphatase and 2) a furosemide-sensitive K+ uptake. The effects of elevation of intracellular calcium concentration ([Ca2+]i) on Ba2+ and furosemide-sensitive K+ flux pathways were studied. Elevation of [Ca2+]i had minor effects on Ba2(+)-sensitive K+ flux. However, elevation of [Ca2+]i produced by exposure to ouabain for 60 min activated a furosemide-sensitive 42K+ efflux and a ouabain-resistant, furosemide-sensitive 42K+ influx. The activation of K+ influx, caused by an increase in [Ca2+]i, was completely inhibited by ATP depletion (produced by exposure to ouabain and metabolic inhibitors simultaneously) and was partially inhibited by the calmodulin inhibitor W7. Activation of the furosemide-sensitive K+ flux was also produced by washout of metabolic inhibitors, a condition in which ATP resynthesis occurs in the presence of an increased [Ca2+]i. Activation of furosemide-sensitive K+ fluxes by exposure to ouabain or washout of metabolic inhibitors caused a net K+ loss, which accounts in part for the cell shrinkage noted during recovery from metabolic inhibition in previous studies. These results suggest that [Ca2+]i and intracellular ATP concentration are important in the regulation of furosemide-sensitive K+ flux in these cells, perhaps via the involvement of a Ca2(+)-calmodulin-dependent protein kinase.

Can Externally Applied Atp Supply Energy to Active Ion Uptake Mechanisms of Intact Plant Cells?

1974 ◽  
Vol 1 (2) ◽  
pp. 211 ◽  
Author(s):  
U Lüttge ◽  
EV Schöch ◽  
E Ball
Keyword(s):  
External Medium ◽  
Divalent Cations ◽  
Plant Cells ◽  
Bundle Sheath ◽  
Metabolic Inhibition ◽  
Ion Uptake ◽  
Intact Plant ◽  
K Uptake ◽  
Atp Supply ◽  
Uptake Mechanisms

ATP applied in the external medium of leaf slices and bundle-sheath preparations at concentrations between 1.0 and 2.5 mM apparently enhances K+ uptake. However, this effect depends on the presence of Ca2+ or Mg2+ in the medium. ATP is shown to release a Ca2+ or Mg2+ inhibition of K+ uptake. If the Ca2+ or Mg2+ content of the medium is varied and EDTA used to mimic the effect of ATP, it can be demonstrated that the observed effect of ATP is entirely explicable by its chelation of divalent cations. Externally applied ATP has similar relative effects on K+ uptake under control conditions and under conditions where metabolism is inhibited, and although it apparently fully releases metabolic inhibition, these experiments reveal ambiguities which are discussed. It is con- cluded that apparent effects of externally applied ATP may often be indirect. The possibility of specific, i.e. energy-providing, effects can nevertheless not be ruled out in principle, but more sophisti- cated experimentation than found hitherto in the literature is required to demonstrate such effects.

Effect of Auxin, Fusicoccin and Tris Buffer on Ion Uptake, Organic Acid Synthesis and Cell Elongation in Barley Coleoptile Segments

1981 ◽  
Vol 8 (5) ◽  
pp. 375
Author(s):  
B Kholdebarin
Keyword(s):  
Organic Acids ◽  
Organic Acid ◽  
Cell Elongation ◽  
Acid Synthesis ◽  
Ion Uptake ◽  
Tris Buffer ◽  
Common Mechanism ◽  
K Uptake ◽  
Presence And Absence ◽  
Total Organic Acid

The effects of auxin, fusicoccin and tris buffer on K+ and Cl- uptake, total organic acids synthesis and cell elongation in barley coleoptile segments were tested. Some differences between the effects of fusicoccin and auxin on cell elongation and ion uptake were observed which support the idea that the two hormones may not be acting through a common mechanism. Tris buffer in the presence and absence of hormones stimulated K+ uptake and inhibited both Cl- absorption and to some extent cell elongation. Tris buffer treatments, which resulted in excess K+ uptake over Cl-, also caused a net synthesis of organic acids in the tissues. In some experiments, the relation between auxin-induced cell elongation and total organic acid synthesis was also examined.

Unterschiedliche Wirkung von Licht auf die Aufnahme von Chlorid und Sulfat in Limnophila-Blätter. Abhängigkeit der Lichtwirkung von der Konzentration der Anionen

1969 ◽  
Vol 24 (3) ◽  
pp. 342-348 ◽  
Author(s):  
Bernhard Penth ◽  
Josef Weigl
Keyword(s):  
Electron Flow ◽  
Developmental State ◽  
Ion Uptake ◽  
Ion Concentration ◽  
Transport Systems ◽  
Chloride Uptake ◽  
Anion Uptake ◽  
Effect Of Light ◽  
Stimulation Of

The effect of light on anion uptake by detached leaves of Limnophila gratioloides was investigated using different external concentrations of chloride and sulfate. The results show that the effect of light may be dependent not only on the plant species 1-4,8,9 and more or less imponderable conditions like the nutritional and developmental state of the plant but also on the external ion concentration and the duration of the uptake period. Chloride uptake by Limnophila leaves from solutions of 0.1 - 1.0 mM/I was not affected by light (4000 Lux), uptake from 1.0 - 10.0 mM/l, by contrast, was stimulated by light in an initial uptake period (4 h), i. e. the km of this system was decreased by light leaving vmax unaltered. Sulfate uptake was inhibited by light if the external sulfate concentration was within the range of 0.01 -7.0 mM/l. Applying external sulfate concentrations from 7.0 - 50.0 mM/l results in stimulation of uptake by light.A workable approximation to these observations may still be that the primary metabolic anion uptake, particularly chloride uptake, into leaf cells is mediated by transport systems which are remote from the mitochondria and chloroplasts and which are supported by a cofactor produced either in oxydative phosphorylation, in cyclic plus noncyclic photophosphorylation or in cyclic photophosphorylation alone 1-4, 9. Since kinetic data are equal in light and in dark, direct coupling of chloride uptake to electron flow in mitochondria or chloroplasts is unlikely. The hypothesis is developed that light may exert a dual influence on ion uptake:1. Metabolic uptake may be influenced by a change in the availability of ATP to transport systems.2. Passive fluxes and counterfluxes of ions across cell membranes may be affected by production or translocation of intracellular ions. Since chloroplasts represent important intracellular compartments, light-induced translocations of ions22 (including Ca2⨁23!) across the chloroplast membranes may exert a marked influence on the overall ion uptake by stimulation of the passive influx of ions across the plasmalemma 15.In line with this views is the observation that in Limnophila leaves, which contain approximately equal ATP levels in light and in dark, there is no stimulation of chloride uptake by light at low external concentrations of KCl while at high external concentrations, at which passive fluxes of ions across the plasmalemma become effective, both ion uptake and ion loss is stimulated by light.The susceptibility to the external ion concentration of the influence of light suggests that effects of light on ion transport ought to be studied at various external ion concentrations.The applicability of imidazole as uncoupler of photophosphorylation in vivo is discussed.

Ion Uptake and Transport through Barley Seedlings: Differential Effect of Cycloheximide

1973 ◽  
Vol 28 (7-8) ◽  
pp. 434-436 ◽  
Author(s):  
André Läuchli ◽  
Ulrich Lüttge ◽  
Michael G. Pitman
Keyword(s):  
Protein Synthesis ◽  
Ion Transport ◽  
Differential Effect ◽  
Ion Uptake ◽  
K Uptake ◽  
Root Cells ◽  
Symplasmic Transport ◽  
Vesicular Secretion ◽  
Uptake And Transport

Cycloheximide inhibits transport of K through barley roots without affecting K uptake and accumulation in the root cells. The inhibitor acts upon protein synthesis but does not appear to uncouple respiration. Requirement of protein synthesis for ion transport through roots is possibly due to involvement of symplasmic transport or vesicular secretion into the xylem.

scholarly journals The effects of inhibition of protein synthesis on the phenotype of Abnormal-abdomen

1973 ◽  
Vol 21 (3) ◽  
pp. 229-238 ◽  
Author(s):  
Ralph Hillman ◽  
Stephen J. Shafer ◽  
James H. Sang
Keyword(s):  
Protein Synthesis ◽  
Oxidative Phosphorylation ◽  
Protein Concentration ◽  
Rna Synthesis ◽  
Genetic System ◽  
Metabolic Inhibitors ◽  
Wild Type ◽  
Mutant Genotype ◽  
Lower Protein ◽  
Sterile Medium

SUMMARYPenetrance and expressivity of the Drosophila mutant Abnormal-abdomen (A53g) may be reduced by adding inhibitors of protein synthesis, of RNA synthesis, and of oxidative phosphorylation to the defined, sterile medium on which larvae are developing. When grown on regular diet, the mutant flies contain a higher concentration of total protein than do wild-type flies. The metabolic inhibitors which reduce the expressivity of the mutation also lower protein concentration in these mutant flies. The reduction of protein synthesis is directly correlated with the reduction of expression of the mutant genotype. The regulation of the morphological abdominal abnormalities by the complex A53g genotype is discussed in relation to the control, by this same genetic system, of the mechanisms of protein synthesis.

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