Not as docile as it looks? Loxosceles venom variation and loxoscelism in the Mediterranean Basin and the Canary Islands.

Abstract

The medical importance of Loxosceles spiders has promoted extensive research on different aspects of their venoms. Most of the reported cases of loxoscelism have occurred in the Americas, and thus, much work has focused on North and South American Loxosceles species. Interestingly, loxoscelism cases are rare in the Mediterranean Basin although Loxosceles rufescens, endemic to the Mediterranean, is an abundant spider even in human-altered areas. Thus, it has been suggested that the venom of L. rufescens could be of less medical relevance than that of its congeners. In this study, we challenge this hypothesis by using multiple approaches to study venom variation in selected species and lineages from the Mediterranean Basin and the Canary Islands. We found that SMase D activity, the key bioactive component of Loxosceles venom, is comparable to American species that are confirmed to have medically relevant bites. The venom protein composition using SDS-PAGE presents some differences among regional Loxosceles taxa in banding pattern and intensity, mostly between the Canarian and L. rufescens lineages. Differences between these species also exist in the expression of different paralogs of the SicTox gene family, with the Canarian species being less diverse. In conclusion, our results do not support the challenged hypothesis, and suggest that venom of these species may indeed be as potent as other Loxosceles species. Pending confirmation of loxoscelism with direct evidence of Loxosceles bites with species identification by professionals, Loxosceles in the Mediterranean region should conservatively be considered medically relevant taxa.

• Authors: Enric Planas, Pamela A Zobel-Thropp, Carles Ribera, Greta Binford
• Journal: Toxicon : official journal of the International Society on Toxinology (Toxicon) Vol. 93 Pg. 11-9 (Jan 2015) ISSN: 1879-3150 [Electronic] England
• PMID: 25449105 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
• Copyright: Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemical References

• DNA Primers
• DNA, Complementary
• Oxazines
• Spider Venoms
• Amplex Red
• Phosphoric Diester Hydrolases
• sphingomyelin phosphodiesterase D

Topics

• Base Sequence
• Bayes Theorem
• Cloning, Molecular
• DNA Primers (genetics)
• DNA, Complementary (genetics)
• Electrophoresis, Polyacrylamide Gel
• Humans
• Mediterranean Region (epidemiology)
• Models, Genetic
• Molecular Sequence Data
• Oxazines
• Phosphoric Diester Hydrolases (genetics, toxicity)
• Phylogeny
• Sequence Analysis, DNA
• Spain (epidemiology)
• Species Specificity
• Spider Bites (epidemiology, physiopathology)
• Spider Venoms (enzymology, toxicity)