Induced hydrogen ion transport in lipid membranes as origin of toxic effect of pentachlorophenol in an alga

Jayaweera, Ranjith; Petersen, Richard R.; Smejtek, P.

doi:10.1016/0048-3575(82)90106-7

Cited by 16 publications

(6 citation statements)

References 19 publications

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“…They have long been known to disrupt cell function by destroying the proton gradient across the inner mitochondrial membrane and therefore uncoupling the oxidative phosphorylation of ATP (Weinbach, 1956). Partitioning of the hydrophobic chlorinated phenols into the lipid phase of the bilayer (Buff et al, 1982) enables proton transport across the membrane (Jayaweera et al, 1982). 1 It has also been shown that their presence decreases the fluidity of lipid bilayers (Duxbury and Thompson, 1987), the gel-to-fluid phase transition temperature (Smejtek et al, 1989), the free amino acid pool in freshwater amphipod Gammarus pseudolimnaeus (Graney and Giesy, Jr., 1987) and the carbon assimilation by algae (Jayaweera et al, 1982).…”

Section: Discussionmentioning

confidence: 99%

Origins of Effective Charge of Multivalent Ions at a Membrane/Water Interface and Distribution of 2,3,4,5-Tetrachlorophenol in a Membrane Model System

Schmidt¹

2000

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First and foremost of all I would like to thank my advisor Pavel Smejtek. With his inspiring humor and scientific comprehension he created a productive but at the same time relaxed working atmosphere. Our fruitful discussions helped me to get a better understanding about the "mysteries of physics" with which we were dealing. The experiments would not have been possible without the encouraging help from Shanru Wang. She had the patience to teach me the basic principles of "wet chemistry" and helped me to overcome many obstacles and frustrations. I am indebted to John Dash who supported my interest in electron microscopy and helped me to get the SEM micrograph of a liposome. I enjoyed working with Isolde Sieder and Robert Ward in our lab. Our discussions and late night sessions won't be forgotten! I want to thank the Physics Department here at Portland State for the obligingness I received in various matters and the unbureaucratical way administrative obstacles were overcome. I appreciate the help from Margie Fyfield during the final writeup of the thesis and all the discussions we had throughout the year. I am grateful for the financial support from the Oregon-Baden Wiirttemberg exchange program. I would like to thank all my friends, here and in Germany, who cheered me up during the busiest time of my research. My family had a major influence on my personal and educational development. Without their support I probably would not have been able to be here at Portland State and would have missed this extraordinary experience. Thank you!

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Section: Discussionmentioning

confidence: 99%

Origins of Effective Charge of Multivalent Ions at a Membrane/Water Interface and Distribution of 2,3,4,5-Tetrachlorophenol in a Membrane Model System

Schmidt¹

2000

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“…PCP is a commonly used pesticide that has been extensively studied [13,21,22,25,26,[32][33][34]. We have found, for example, that the onset of toxic effect due to PCP measured by the rate of carbon assimilation by an alga, occurs in parallel with the decrease of membrane electrical resistance [9]. The effect of PCBT on oxidative phosphorylation in rat liver mitochondria and on electrical conductivity of the lipid bilayer membranes have been studied by Wilson et al [36].…”

Section: Introductionmentioning

confidence: 96%

Electrical conductivity, transfer of hydrogen ions in lipid bilayer membranes and uncoupling effect induced by pentachlorobenzenethiol (Pentachlorothiophenol)

1983

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Pentachlorobenzenethiol (PCBT) has been considered an anomalous uncoupler. It was reported as active in mitochondria, but not effective in inducing electrical conductivity in lipid bilayer membranes. We have overcome the experimental difficulties associated with accurate determination of the induced conductivity. The main contributing factors to the difficulties, we discovered, are the photolability and the low solubility of the compound in aqueous medium. We have conclusively demonstrated that PCBT does induce conductivity in lipid bilayers and compared this conductance with its uncoupling activity reported by other investigators in the literature. We present the results of steady-state current-voltage measurements: conductance dependence on applied voltage for various values of pH, buffer strength and PCBT concentration, as well as the dependence of the conductance on pH, buffer strength and PCBT concentration in the limit of zero applied voltage. We have also compared the above results with those obtained previously with pentachlorophenol. Our experimental results on PCBT-induced membrane conductance suggest that PCBT belongs to class II uncouplers and that "disulfide dimer" of PCBT is membrane inactive. Thus the replacement of oxygen in molecular structure of pentachlorophenol (R-OH) by sulfur (R-SH) does not change the protonophoretic activity of the compound. The conductivity of a membrane is due to PCBT-induced hydrogen ion transfer and it was found to be limited by the kinetics of reactions coupled to transmembrane charge transfer.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Moreland and Hilton [19] classify PCP as an inhibitory uncoupler, recognizing that its sites of action are several, including photophosphorylation, protein synthesis and lipid biosynthesis [20]. The mechanism(s) of PCP's toxicity remains to be precisely defined, but current evidence points to the disruption of membrane function [16,17,21].…”

Section: Introductionmentioning

confidence: 99%

EFFECTS OF HARDNESS, ALKALINITY AND pH ON THE TOXICITY OF PENTACHLOROPHENOL TO SELENASTRUM CAPRICORNUTUM (PRINTZ)

Smith¹,

Brockway²,

Stancil³

1987

Environ Toxicol Chem

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The toxicity of pentachlorophenol (PCP) to Selenastrum capricornutum was examined in three different culture media: a hard and a soft form of Freeman's reference water and the algal assay bottle test (AABT) medium (a soft water). The 96-h growth potentials of the media were equal (28-29 mg/L dry wt.) but 96-h EC5Os ranged sevenfold: 0.11 mg/L (AABT), 0.15 mg/L (Freeman's soft water) and 0.76 mg/L (Freeman's hard water). Culture media equilibrium pH and 96-h EC50 were strongly correlated ( r = 1.00). Evidence is presented that supports the hypothesis that the toxicity of PCP, a weak acid, is due primarily :o the concentration of the undissociated species.

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Induced hydrogen ion transport in lipid membranes as origin of toxic effect of pentachlorophenol in an alga

Cited by 16 publications

References 19 publications

Origins of Effective Charge of Multivalent Ions at a Membrane/Water Interface and Distribution of 2,3,4,5-Tetrachlorophenol in a Membrane Model System

Origins of Effective Charge of Multivalent Ions at a Membrane/Water Interface and Distribution of 2,3,4,5-Tetrachlorophenol in a Membrane Model System

Electrical conductivity, transfer of hydrogen ions in lipid bilayer membranes and uncoupling effect induced by pentachlorobenzenethiol (Pentachlorothiophenol)

EFFECTS OF HARDNESS, ALKALINITY AND pH ON THE TOXICITY OF PENTACHLOROPHENOL TO SELENASTRUM CAPRICORNUTUM (PRINTZ)

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