Borges Adolfo, García Carmen C, Lugo Elizabeth, Alfonzo Marcelo J, Jowers Michael J, Op den Camp Huub J M
Sección de Biomembranas, Instituto de Medicina Experimental, Universidad Central de Venezuela, Caracas 1051, Venezuela.
Sección de Biomembranas, Instituto de Medicina Experimental, Universidad Central de Venezuela, Caracas 1051, Venezuela.
Comp Biochem Physiol C Toxicol Pharmacol. 2006 Mar-Apr;142(3-4):240-252. doi: 10.1016/j.cbpc.2005.10.011. Epub 2005 Dec 13.
In Venezuela, stings by Tityus zulianus scorpions produce cardiorespiratory arrest, whereas envenoming by Tityus discrepans involves gastrointestinal/pancreatic complications, suggesting structural and/or functional differences. We sought to compare their toxin repertoires through immunological, molecular, and mass spectral analyses. First, in vivo tests showed that neutralization of T. zulianus venom toxicity by the anti-T. discrepans antivenom was not complete. To compare T. discrepans and T. zulianus long-chain (sodium channel-active) toxins, their most toxic Sephadex G-50 fractions, TdII and TzII, were subjected to acid-urea PAGE, which showed differences in composition. Amplification of toxin-encoding mRNAs using a leader peptide-based oligonucleotide rendered cDNAs representing twelve T. discrepans and two T. zulianus distinct toxin transcripts, including only one shared component, indicating divergence between T. zulianus and T. discrepans 5' region-encoded, toxin signal peptides. A 3'-UTR polymorphism was also noticed among the transcripts encoding shared components Tz1 and Td4. MALDI-TOF MS profiling of TdII and TzII produced species-specific spectra, with seven of the individual masses matching those predicted by cDNA sequencing. Phylogenetic analysis showed that the unique T. zulianus transcript-encoded sequence, Tz2, is structurally related to Tityus serrulatus and Centruroides toxins. Together with previous reports, this work indicates that T. zulianus and T. discrepans toxin repertoires differ structurally and functionally.
在委内瑞拉，朱利安斯肥尾蝎蜇伤会导致心肺骤停，而多异肥尾蝎的毒液则会引发胃肠道/胰腺并发症，这表明两者在结构和/或功能上存在差异。我们试图通过免疫学、分子和质谱分析来比较它们的毒素库。首先，体内试验表明，抗多异肥尾蝎抗蛇毒血清对朱利安斯肥尾蝎毒液毒性的中和并不完全。为了比较多异肥尾蝎和朱利安斯肥尾蝎的长链（钠通道活性）毒素，对它们毒性最强的葡聚糖凝胶G - 50组分TdII和TzII进行了酸性尿素聚丙烯酰胺凝胶电泳，结果显示其组成存在差异。使用基于前导肽的寡核苷酸对毒素编码mRNA进行扩增，得到了代表12种多异肥尾蝎和2种朱利安斯肥尾蝎不同毒素转录本的cDNA，其中只有一个共同成分，这表明朱利安斯肥尾蝎和多异肥尾蝎5'区域编码的毒素信号肽存在差异。在编码共同成分Tz1和Td4的转录本中还发现了3'-非翻译区多态性。对TdII和TzII进行基质辅助激光解吸电离飞行时间质谱分析，得到了物种特异性图谱，其中7个个体质量与cDNA测序预测的质量相符。系统发育分析表明，朱利安斯肥尾蝎独特的转录本编码序列Tz2在结构上与锯齿肥尾蝎和正钳蝎毒素相关。结合之前的报道，这项研究表明朱利安斯肥尾蝎和多异肥尾蝎的毒素库在结构和功能上存在差异。
