Document Detail

Effects of the Bacillus thuringiensis toxin Cry1Ab on membrane currents of isolated cells of the ruminal epithelium.
MedLine Citation:
PMID:  17676405     Owner:  NLM     Status:  MEDLINE    
A previous study has shown that Cry1Ab, a lepidopteran-specific toxin derived from Bacillus thuringiensis, does not affect the vitality of cultured cells of the ruminal epithelium of the sheep. While this may be due to lack of specific receptors for toxin action, other mechanisms of resistance should also be considered. In order to directly assess the pore-forming potential of Cry1Ab, we studied the interaction of this toxin with isolated, perfused cells of the ruminal epithelium using the whole-cell and single-channel configurations of the patch-clamp technique. At concentrations found in vivo in the rumen of cows (<10 ng/ml) and at a temperature of 37 degrees C, no significant effects of Cry1Ab could be observed. At 100 ng/ml, exposure of ruminal cells to Cry1Ab induced a significant rise in outward current in 16 of 34 cells, with a fourfold increase in the conductance for potassium. The cell membrane remained selective for potassium over sodium (p(K)/p(Na) = 1.8 + or - 0.3), with a considerable additional chloride conductance. In outside-out patches, exposure to high Cry1Ab concentrations induced channel-like events that reached levels of over 500 pS. We conclude that the unchanged vitality of intact ruminal epithelial cells exposed to Cry1Ab in vitro at high concentrations may be related to other factors besides the proposed absence of a specific receptor for the membrane insertion of this toxin.
Friederike Stumpff; Angelika Bondzio; Ralf Einspanier; Holger Martens
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-08-05
Journal Detail:
Title:  The Journal of membrane biology     Volume:  219     ISSN:  0022-2631     ISO Abbreviation:  J. Membr. Biol.     Publication Date:  2007 Oct 
Date Detail:
Created Date:  2007-11-29     Completed Date:  2008-02-27     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0211301     Medline TA:  J Membr Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  37-47     Citation Subset:  IM    
Department of Veterinary Physiology, Free University of Berlin, Oertzenweg 19b, 14163, Berlin, Germany.
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MeSH Terms
Bacterial Proteins / toxicity*
Bacterial Toxins / toxicity*
Calcium / metabolism
Cell Membrane Permeability
Endotoxins / toxicity*
Epithelial Cells / drug effects,  metabolism
Hemolysin Proteins / toxicity*
Ion Channels / drug effects,  metabolism
Magnesium / metabolism
Membrane Potentials / drug effects
Patch-Clamp Techniques
Rumen / cytology,  drug effects*,  metabolism*
Signal Transduction
Reg. No./Substance:
0/Bacterial Proteins; 0/Bacterial Toxins; 0/Endotoxins; 0/Hemolysin Proteins; 0/Ion Channels; 0/insecticidal crystal protein, Bacillus Thuringiensis; 7439-95-4/Magnesium; 7440-70-2/Calcium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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