Chemical and Functional Characterization of Scorpion Toxins 
Using monoclonal antibodies, we found four 
main distinct antigenic determinants in the Na"'" 
channel target toxins of eight different species of 
scorpion from the American continent. One of 
the antibodies was shown to produce an impor- 
tant protection to experimental animals enveno- 
mated with highly purified toxin. This result is 
also important for developing possible synthetic 
peptides for vaccination. 
Cloning of Scorpion Toxin Genes 
The most recent advance of our laboratory, in 
collaboration with Francisco Bolivar and Baltazar 
Becerril, was the successful isolation of several 
clones that code for peptides corresponding to 
the amino acid sequence of scorpion toxins. A 
cDNA library was prepared from the telsons of the 
scorpions C. noxius and C. limpidus limpidus. 
In the future we hope to use directed mutagene- 
sis to obtain specific modified toxins in order to 
study the structure-function relationship of these 
ligands with specific ion channels. 
Search for New Toxins 
New, unknown peptides toxic to insects and 
crustaceans were purified and are being se- 
quenced. These are from several species of scor- 
pion, including some not dangerous to humans. 
Also, in collaboration with Hector Valdivia and 
Roberto Coronado from Madison University, we 
are conducting a search for specific toxins that 
target the Ca^"'" release channel from the sarco- 
plasmic reticulum. 
This research is supported in part by grants 
from the Consejo Nacional de Ciencia y Techno- 
logia, Mexico, and Direccion General del Per- 
sonal Academico, from the National Autonomous 
University of Mexico. 
Venom extraction by electrical stimulation of a scorpion, species Hadrurus concolorous. 
Photograph by Manuel Varela and Lourival Possani. 
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