Scorpions from the primeval subgenus Archaeotityus produce putative homologs of Tityus serrulatus toxins active on voltage-gated sodium channels

Borges A (1, 2), Jowers MJ (3), Bónoli S (2, 4), De Sousa L (2, 4)

(1) Laboratory of Molecular Biology of Toxins and Receptors, Biomembranes Section, Institute of Experimental Medicine, Faculty of Medicine, Central University of Venezuela, Caracas, Venezuela; (2) Research Group on Applied Toxinology and Venomous Animals, University of Oriente, Anzoátegui Campus, Puerto La Cruz, Venezuela; (3) Superior Council of Scientific Research, Department of Etiology and Biodiversity Conservation, Biological Station of Doñana, La Cartuja Island, Seville, Spain; (4) Laboratory of Toxinology, Department of Physiological Sciences, School of Health Sciences, University of Oriente, Anzoátegui Campus, Puerto La Cruz, Venezuela.

Abstract: It has been proposed that the subgenus Archaeotityus comprises the most ancient species group within the medically important scorpion genus Tityus. cDNA encoding sodium-channel active toxins from the type species of this subgenus, Tityus clathratus (central Venezuela), have been isolated and sequenced. Two cDNAs were retrieved that encoded 61 amino acid-long putative neurotoxins named Tcl1 and Tcl2. Sequence identity was highest (87%) when both were compared with β-toxin Ts1 from the Brazilian scorpion Tityus serrulatus and its homologs from T. bahiensis, T. stigmurus, and T. costatus. A Bayesian analysis indicated statistical support for the grouping of T. clathratus Tcl1 and Tcl2 with Brazilian gamma-like β-toxins, reinforcing previous phylogenetic studies which suggested an evolutionary relationship between the subgenus Archaeotityus and scorpion species inhabiting southeast South America belonging to the subgenus Tityus.

Key words: Archaeotityus, scorpions, scorpion toxins, Tityus, Tityus clathratus, Tityus serrulatus.

ACKNOWLEDGMENTS

We are thankful to Lic. Javier Valera Leal and Lic. Aleikar Vásquez for their help during scorpion collection. Financial support from the Council for Scientific and Humanistic Development, Central University of Venezuela, and the Investigation Council of University of Oriente is gratefully acknowledged.

COPYRIGHT

© CEVAP 2012

SUBMISSION STATUS

Received: March 23, 2012.

Accepted: August 31, 2012.

Abstract published online: September 3, 2012.

Full paper published online: November 30, 2012.

CONFLICTS OF INTEREST

The authors declare no conflicts of interest.

FINANCIAL SOURCE

The Council for Scientific and Humanistic Development, Central University of Venezuela (CDCH-UCV) grant n. PG-09-7767-2009/2 (to Adolfo Borges) and Investigation Council of University of Oriente grant n. CI-3-040602-1342/07 (to Leonardo de Sousa) provided the financial grants.

ETHICS COMMITTEE APPROVAL

The present study was approved by the Ethics Committee of the Institute of Experimental Medicine, Central University of Venezuela.

CORRESPONDENCE TO

Adolfo Borges, Instituto de Medicina Experimental, Facultad de Medicina, Universidad Central de Venezuela, Apartado Postal 50587, Caracas 1050, Venezuela. Phone: +58212 6053608. Fax: +58212 6628877. Email: borges.adolfo@gmail.com.