Non-specific binding of palytoxin to plastic surfaces

Taylor, Thomas J.; Parker, Gerald W.; Fajer, A. B.; Mereish, K. A.

doi:10.1016/0378-4274(91)90203-i

Cited by 7 publications

(6 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the onset rate of the PTX effect, we were faced with the problem that the effect of PTX was rather variable in amplitude as well as in onset rate, and then both parameters tended to decrease during the course of an experiment. We attributed this problem to the instability of PTX in our solution and/or possibly to binding of PTX to various elements of the perfusion circuit [20], resulting in an uncertain concentration of active PTX in our solution. Therefore, we assumed that we could not know with precision the effective concentration of active PTX in our solutions and we renounced drawing any conclusions concerning the absolute value of the k on or of the affinity.…”

Section: Resultsmentioning

confidence: 99%

Palytoxin effects through interaction with the Na,K‐ATPase in Xenopus oocyte

Wang

Horisberger

1997

FEBS Letters

View full text Add to dashboard Cite

Palytoxin (PTX) is known to bind to Na,K-ATPase, to inhibit its activity, and to induce cation conductance, but the mechanism of these effects is still poorly understood. In Xenopus oocytes, PTX induced a large cation conductance, an effect that could be prevented or reversed by ouabain for oocytes expressing Xenopus Na,K-pumps but not with those expressing Bufo Na,Kpumps. In both cases patch-clamp experiments demonstrated a 7-8 pS channel in the presence of PTX. A large PTX-induced conductance could be observed with minimal Na,K-pump inhibition. From the single PTX-induced channel and macroscopic whole oocyte conductance, and the number of Na,Kpumps, we can conclude that PTX-induced conductance occurs through a direct interaction of PTX with a small number of Na,K-pumps.

show abstract

Section: Resultsmentioning

confidence: 99%

Palytoxin effects through interaction with the Na,K‐ATPase in Xenopus oocyte

Wang

Horisberger

1997

FEBS Letters

View full text Add to dashboard Cite

show abstract

“…An aliquot of frozen 100 M PTX (from Palythoa toxica ; Calbiochem) aqueous solution was thawed and diluted into external solutions just before each experiment. All PTX-containing solutions also included ‫ف‬ 0.002% BSA to reduce PTX binding to nonglass surfaces (Taylor et al, 1991). Strophanthidin was added from a 1-M stock solution in DMSO, and ouabain and dihydroouabain were dissolved in the appropriate external solution at their final concentration.…”

Section: Solutionsmentioning

confidence: 99%

Large Diameter of Palytoxin-induced Na/K Pump Channels and Modulation of Palytoxin Interaction by Na/K Pump Ligands

Artigas

Gadsby

2004

The Journal of General Physiology

102

114

View full text Add to dashboard Cite

Palytoxin binds to Na/K pumps to generate nonselective cation channels whose pore likely comprises at least part of the pump's ion translocation pathway. We systematically analyzed palytoxin's interactions with native human Na/K pumps in outside-out patches from HEK293 cells over a broad range of ionic and nucleotide conditions, and with or without cardiotonic steroids. With 5 mM internal (pipette) [MgATP], palytoxin activated the conductance with an apparent affinity that was highest for Na+-containing (K+-free) external and internal solutions, lowest for K+-containing (Na+-free) external and internal solutions, and intermediate for the mixed external Na+/internal K+, and external K+/internal Na+ conditions; with Na+ solutions and MgATP, the mean dwell time of palytoxin on the Na/K pump was about one day. With Na+ solutions, the apparent affinity for palytoxin action was low after equilibration of patches with nucleotide-free pipette solution. That apparent affinity was increased in two phases as the equilibrating [MgATP] was raised over the submicromolar, and submillimolar, ranges, but was increased by pipette MgAMPPNP in a single phase, over the submillimolar range; the apparent affinity at saturating [MgAMPPNP] remained ∼30-fold lower than at saturating [MgATP]. After palytoxin washout, the conductance decay that reflects palytoxin unbinding was accelerated by cardiotonic steroid. When Na/K pumps were preincubated with cardiotonic steroid, subsequent activation of palytoxin-induced conductance was greatly slowed, even after washout of the cardiotonic steroid, but activation could still be accelerated by increasing palytoxin concentration. These results indicate that palytoxin and a cardiotonic steroid can simultaneously occupy the same Na/K pump, each destabilizing the other. The palytoxin-induced channels were permeable to several large organic cations, including N-methyl-d-glucamine+, suggesting that the narrowest section of the pore must be ∼7.5 Å wide. Enhanced understanding of palytoxin action now allows its use for examining the structures and mechanisms of the gates that occlude/deocclude transported ions during the normal Na/K pump cycle.

show abstract

“…To prevent potential nonspecific binding of PLTX to plastic surfaces , we performed an overnight incubation of all the experimental instruments with Caco‐2 standard growth medium supplemented with 1% BSA. A post‐incubation washing step with standard growth medium supplemented with 0.5% BSA leaves the plastic devices ready for the experiments.…”

Section: Methodsmentioning

confidence: 99%

The kinetic, mechanistic and cytomorphological effects of palytoxin in human intestinal cells (Caco‐2) explain its lower‐than‐parenteral oral toxicity

et al. 2013

View full text Add to dashboard Cite

Palytoxin is one of the most toxic marine toxins known. Distributed worldwide, it poses a potential human health risk linked to the consumption of contaminated seafood. Despite its high parenteral toxicity, the lethal oral dose of palytoxin is several times higher than the intraperitoneal lethal dose. In the present study, we investigated the passage of palytoxin through the human intestinal barrier by employing a well-characterized and accepted in vitro model of intestinal permeability that uses differentiated Caco-2 cell monolayers. Trans-epithelial electric resistance measurements showed that palytoxin disrupts the integrity of Caco-2 monolayers at concentrations > 0.135 nM. However, confocal microscopy imaging showed that the tight-junction protein occludin was not affected by palytoxin in the nanomolar range. This finding was supported by transmission electron microscopy imaging, where tight-junctions appeared to be unaffected by palytoxin treatment. In addition, the nuclear envelope does not appear to be altered by high concentrations of palytoxin. However, palytoxin-treated cells showed electron-dense and damaged mitochondria. Toxin exposure also induced the disappearance of the differentiated Caco-2 microvilli and organelles, as well as chromatin de-condensation. Permeability assays showed that palytoxin could not significantly pass the Caco-2 monolayer, despite the lack of epithelium integrity, suggesting that palytoxins would be poorly transported to blood, which may explain its lower oral toxicity. These data can help to achieve a better understanding of palytoxin poisoning. However, more studies regarding its repeated administration and chronic effects are needed.

show abstract

Non-specific binding of palytoxin to plastic surfaces

Cited by 7 publications

References 8 publications

Palytoxin effects through interaction with the Na,K‐ATPase in Xenopus oocyte

Palytoxin effects through interaction with the Na,K‐ATPase in Xenopus oocyte

Large Diameter of Palytoxin-induced Na/K Pump Channels and Modulation of Palytoxin Interaction by Na/K Pump Ligands

The kinetic, mechanistic and cytomorphological effects of palytoxin in human intestinal cells (Caco‐2) explain its lower‐than‐parenteral oral toxicity

Contact Info

Product

Resources

About