Skip to main content
NCBI home page
Plant Physiology logoLink to Plant Physiology
. 1984 Jan;74(1):61–66. doi: 10.1104/pp.74.1.61

Perturbation of Chara Plasmalemma Transport Function by 2[4(2′,4′-Dichlorophenoxy)phenoxy]propionic Acid 1

William J Lucas 1,2,3, Clyde Wilson 1,2,3, John P Wright 1,2,3
PMCID: PMC1066624  PMID: 16663386

Abstract

Electrophysiological measurements on internodal cells of Chara corallina Klein ex Willd., em. R.D.W. revealed that in the presence of (2-[4-(2′,4′-dichlorophenoxy)phenoxy]propionic acid) (diclofop) the membrane potential was very sensitive to the pH of the bathing medium. At pH 5.7, 100 micromolar diclofop caused a slow reduction in the electrogenic component of the membrane potential to the value of −123 ± 5 millivolts. Membrane resistance initially decreased, recovered transiently, then stabilized at approximately 65% of the control value. At pH 7.0, the potential appeared to plateau around −200 millivolts before rapidly declining to −140 ± 4 millivolts; removal of diclofop resulted in recovery of the electrogenic component. Diclofop reduced cytoplasmic ATP levels by 96.4% and 36.6% at pH 5.7 and 7.0, respectively. At pH 8.2, diclofop did not change the ATP concentration significantly, but induced a hyperpolarization of the membrane potential to near −250 millivolts, and also reduced or inhibited the dark-induced hyperpolarization; the light-induced depolarization was reduced to a lesser extent. DCMU applied in the light elicited the same response at the plasmalemma as placing cells in the dark. When K+ channels were opened and cells depolarized with 10 millimolar K+, diclofop induced a further depolarization of approximately 30 millivolts. Cells decoupled with HPO4−2 were still sensitive to diclofop. Currents associated with OH− efflux and HCO3− influx, as measured with a vibrating probe technique, became spatially destabilized and reduced in magnitude in the presence of diclofop. After 60 minutes, most of the cell surface was engaged in a low level of OH− efflux activity. The results indicate that diclofop may be a proton ionophore at pH 7.0 and 5.7. At pH 8.2, diclofop may inhibit the operation of the H+-ATPase and OH− efflux systems associated with HCO3− transport by perturbing the control processes that integrate the two, without a reduction in ATP concentration.

Full text

PDF
61

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Benisek W. F., Ogez J. R. Proton nuclear magnetic resonance studies of Pseudomonas testosteroni 3-oxo-delta 5-steroid isomerase and its interaction with 17 beta-estradiol. Biochemistry. 1982 Nov 9;21(23):5816–5825. doi: 10.1021/bi00266a015. [DOI] [PubMed] [Google Scholar]
  2. Chapman A. G., Fall L., Atkinson D. E. Adenylate energy charge in Escherichia coli during growth and starvation. J Bacteriol. 1971 Dec;108(3):1072–1086. doi: 10.1128/jb.108.3.1072-1086.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Hogg J., Williams E. J., Johnston R. J. A simplified method for measuring membrane resistances in Nitella translucens. Biochim Biophys Acta. 1968 Apr 29;150(3):518–520. doi: 10.1016/0005-2736(68)90152-1. [DOI] [PubMed] [Google Scholar]
  4. Jaffe L. F., Nuccitelli R. An ultrasensitive vibrating probe for measuring steady extracellular currents. J Cell Biol. 1974 Nov;63(2 Pt 1):614–628. doi: 10.1083/jcb.63.2.614. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Keifer D. W., Lucas W. J. Potassium Channels in Chara corallina: CONTROL AND INTERACTION WITH THE ELECTROGENIC H PUMP. Plant Physiol. 1982 Apr;69(4):781–788. doi: 10.1104/pp.69.4.781. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Keifer D. W., Spanswick R. M. Activity of the Electrogenic Pump in Chara corallina as Inferred from Measurements of the Membrane Potential, Conductance, and Potassium Permeability. Plant Physiol. 1978 Oct;62(4):653–661. doi: 10.1104/pp.62.4.653. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Keifer D. W., Spanswick R. M. Correlation of Adenosine Triphosphate Levels in Chara corallina with the Activity of the Electrogenic Pump. Plant Physiol. 1979 Aug;64(2):165–168. doi: 10.1104/pp.64.2.165. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Kimmich G. A., Randles J., Brand J. S. Assay of picomole amounts of ATP, ADP, and AMP using the luciferase enzyme system. Anal Biochem. 1975 Nov;69(1):187–206. doi: 10.1016/0003-2697(75)90580-1. [DOI] [PubMed] [Google Scholar]
  9. Lichtner F. T., Spanswick R. M. Electrogenic sucrose transport in developing soybean cotyledons. Plant Physiol. 1981 Apr;67(4):869–874. doi: 10.1104/pp.67.4.869. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Lucas W. J., Dainty J. HCO(3) Influx Across the Plasmalemma of Chara corallina: Divalent Cation Requirement. Plant Physiol. 1977 Dec;60(6):862–867. doi: 10.1104/pp.60.6.862. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Lucas W. J. HCO(3) Influx across the Plasmalemma of Chara corallina: Physiological and Biophysical Influence of 10 mm K. Plant Physiol. 1978 Apr;61(4):487–493. doi: 10.1104/pp.61.4.487. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Sanders D., Hansen U. P., Slayman C. L. Role of the plasma membrane proton pump in pH regulation in non-animal cells. Proc Natl Acad Sci U S A. 1981 Sep;78(9):5903–5907. doi: 10.1073/pnas.78.9.5903. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Sanders D., Slayman C. L. Control of intracellular pH. Predominant role of oxidative metabolism, not proton transport, in the eukaryotic microorganism Neurospora. J Gen Physiol. 1982 Sep;80(3):377–402. doi: 10.1085/jgp.80.3.377. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Seliger H. H., McElroy W. D. THE COLORS OF FIREFLY BIOLUMINESCENCE: ENZYME CONFIGURATION AND SPECIES SPECIFICITY. Proc Natl Acad Sci U S A. 1964 Jul;52(1):75–81. doi: 10.1073/pnas.52.1.75. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES