McElroy Thomas, McReynolds C Neal, Gulledge Alyssa, Knight Kelci R, Smith Whitney E, Albrecht Eric A
Department of Ecology, Evolution and Organismal Biology, Kennesaw State University, Kennesaw, GA, United States of America.
Department of Biology and Chemistry, Texas A&M International University, Laredo, TX, United States of America.
PLoS One. 2017 Oct 4;12(10):e0184695. doi: 10.1371/journal.pone.0184695. eCollection 2017.
Variation in venom toxicity and composition exists in many species. In this study, venom potency and venom gland gene expression was evaluated in Centruroides vittatus, size class I-II (immature) and size class IV (adults/penultimate instars) size classes. Venom toxicity was evaluated by probit analysis and returned ED50 values of 50.1 μg/g for class IV compared to 134.2 μg/g for class I-II 24 hours post injection, suggesting size class IV was 2.7 fold more potent. Next generation sequencing (NGS and qPCR were used to characterize venom gland gene expression. NGS data was assembled into 36,795 contigs, and annotated using BLASTx with UNIPROT. EdgeR analysis of the sequences showed statistically significant differential expression in transcripts associated with sodium and potassium channel modulation. Sodium channel modulator expression generally favored size class IV; in contrast, potassium channel modulators were favored in size class I-II expression. Real-time quantitative PCR of 14 venom toxin transcripts detected relative expression ratios that paralleled NGS data and identified potential family members or splice variants for several sodium channel modulators. Our data suggests ontogenetic differences in venom potency and venom related genes expression exist between size classes I-II and IV.
许多物种的毒液毒性和成分存在差异。在本研究中，对I-II级（未成熟）和IV级（成年/倒数第二龄）大小等级的条纹鞭尾蝎的毒液效力和毒腺基因表达进行了评估。通过概率分析评估毒液毒性，注射后24小时，IV级的半数致死量（ED50）值为50.1μg/g，而I-II级为134.2μg/g，这表明IV级的效力是I-II级的2.7倍。使用下一代测序（NGS）和定量聚合酶链反应（qPCR）来表征毒腺基因表达。NGS数据被组装成36,795个重叠群，并使用BLASTx与通用蛋白质数据库（UNIPROT）进行注释。对这些序列的EdgeR分析显示，与钠和钾通道调节相关的转录本存在统计学上的显著差异表达。钠通道调节剂的表达通常在IV级中更常见；相反，钾通道调节剂在I-II级表达中更常见。对14种毒液毒素转录本进行实时定量PCR检测到的相对表达比率与NGS数据一致，并确定了几种钠通道调节剂的潜在家族成员或剪接变体。我们的数据表明，I-II级和IV级大小等级之间在毒液效力和毒液相关基因表达上存在个体发育差异。
