Identification and Phylogenetic Analysis of Tityus pachyurus and Tityus obscurus Novel Putative Na+-Channel Scorpion Toxins

Abstract

BackgroundColombia and Brazil are affected by severe cases of scorpionism. In Colombia the most dangerous accidents are caused by Tityus pachyurus that is widely distributed around this country. In the Brazilian Amazonian region scorpion stings are a common event caused by Tityus obscurus. The main objective of this work was to perform the molecular cloning of the putative Na+-channel scorpion toxins (NaScTxs) from T. pachyurus and T. obscurus venom glands and to analyze their phylogenetic relationship with other known NaScTxs from Tityus species.Methodology/Principal FindingscDNA libraries from venom glands of these two species were constructed and five nucleotide sequences from T. pachyurus were identified as putative modulators of Na+-channels, and were named Tpa4, Tpa5, Tpa6, Tpa7 and Tpa8; the latter being the first anti-insect excitatory β-class NaScTx in Tityus scorpion venom to be described. Fifteen sequences from T. obscurus were identified as putative NaScTxs, among which three had been previously described, and the others were named To4 to To15. The peptides Tpa4, Tpa5, Tpa6, To6, To7, To9, To10 and To14 are closely related to the α-class NaScTxs, whereas Tpa7, Tpa8, To4, To8, To12 and To15 sequences are more related to the β-class NaScTxs. To5 is possibly an arthropod specific toxin. To11 and To13 share sequence similarities with both α and β NaScTxs. By means of phylogenetic analysis using the Maximum Parsimony method and the known NaScTxs from Tityus species, these toxins were clustered into 14 distinct groups.Conclusions/SignificanceThis communication describes new putative NaScTxs from T. pachyurus and T. obscurus and their phylogenetic analysis. The results indicate clear geographic separation between scorpions of Tityus genus inhabiting the Amazonian and Mountain Andes regions and those distributed over the Southern of the Amazonian rainforest. Based on the consensus sequences for the different clusters, a new nomenclature for the NaScTxs is proposed.

Purificación parcial de péptidos y actividad citotóxica del veneno T. macrochirus

“…También, puede señalarse que los componentes proteicos del veneno de diferentes géneros y especies de escorpión varían en cuanto a la cantidad de péptidos o proteínas, pero mantienen su similitud estructural (3,5,7,11,28,(33)(34)(35)(36), lo cual sugeriría una actividad biológica específica en los péptidos del veneno de T. macrochirus.…”

“…2003. p. 381-5), que poseen características farmacológicas, fisiológicas y bioquímicas, las cuales se han determinado y caracterizado estructural y funcionalmente mediante técnicas bioquímicas, como la cromatografía de exclusión (filtración en gel) (1), el intercambio iónico (2) y la cromatografía de alta resolución (HPLC), entre otras (3,4). La determinación de la secuencia de aminoácidos se hace mediante la degradación de Edman o la espectrometría de masas (5); otras técnicas incluyen ensayos de clonación molecular (6)(7)(8).…”

Estudo clínico-epidemiológico, laboratorial e de vulnerabilidade dos acidentes escorpiônicos atendidos no Hospital Municipal de Santarém - Pará

“…As toxinas escorpiônicas atuam particularmente em canais de sódio e potássio, mas também há toxinas com atividade sobre canais de cloreto e cálcio (Possani, 1999;Guerrero-Vargas et al, 2012). As toxinas de escorpião, que atuam nos canais iônicos de sódio, são consideradas as principais toxinas de cadeias longas, que tem 55 a 76 resíduos de aminoácidos.…”

“…A maioria das toxinas beta foi isolada de escorpiões do Novo Mundo, sendo que muitas já foram sequenciadas (Gordon et al,1998). Guerrero-Vargas, et al, 2012 descreveram quinze toxinas distintas do veneno de T. obscurus que atuam em canais de sódio, sendo que três já tinham sido previamente relatadas:…”

“…Guerrero-Vargas, et al, 2012 também propõem nova nomenclatura: substituindo as iniciais Tc (antigo nome da espécie T.…”