Venom complexity of Bothrops atrox (common lancehead) siblings

Abstract Background: Variability in snake venoms is a well-studied phenomenon. However, sex-based variation of Bothrops atrox snake venom using siblings is poorly investigated. Bothrops atrox is responsible for the majority of snakebite accidents in the Brazilian Amazon region. Differences in the venom composition of Bothrops genus have been linked to several factors such as ontogeny, geographical distribution, prey preferences and sex. Thus, in the current study, venom samples of Bothrops atrox male and female siblings were analyzed in order to compare their biochemical and biological characteristics. Methods: Venoms were collected from five females and four males born from a snake captured from the wild in São Bento (Maranhão, Brazil), and kept in the Laboratory of Herpetology of Butantan Intitute. The venoms were analyzed individually and as a pool of each gender. The assays consisted in protein quantification, 1-DE, mass spectrometry, proteolytic, phospholipase A2, L-amino acid oxidase activities, minimum coagulant dose upon plasma, minimum hemorrhagic dose and lethal dose 50%. Results: Electrophoretic profiles of male’s and female’s venom pools were quite similar, with minor sex-based variation. Male venom showed higher LAAO, PLA2 and hemorrhagic activities, while female venom showed higher coagulant activity. On the other hand, the proteolytic activities did not show statistical differences between pools, although some individual variations were observed. Meanwhile, proteomic profile revealed 112 different protein compounds; of which 105 were common proteins of female’s and male’s venom pools and seven were unique to females. Despite individual variations, lethality of both pools showed similar values. Conclusion: Although differences between female and male venoms were observed, our results show that individual variations are significant even between siblings, highlighting that biological activities of venoms and its composition are influenced by other factors beyond gender.

摘要 背景：蛇毒的变异性是一项已被广泛研究的科学现象。然而，以同窝幼体为研究对象的矛头蝮（Bothrops atrox）蛇毒性别差异研究仍较为匮乏。矛头蝮是巴西亚马逊地区绝大多数蛇咬伤事故的致病物种。蝮蛇属（Bothrops）蛇毒成分的差异已被证实与多个因素相关，包括个体发育、地理分布、猎物偏好以及性别。因此，本研究采集并分析了矛头蝮雌雄同窝幼体的蛇毒样本，以对比二者的生化与生物学特性。
方法：蛇毒样本采集自一只野生捕获于巴西马拉尼昂州圣本图的雌性成体，其产下的5只雌性幼体与4只雄性幼体均饲养于布坦坦研究所（Butantan Institute）爬虫学实验室。研究分别对单份蛇毒样本及雌雄各组的混合蛇毒进行分析。检测项目包括：蛋白质定量、一维凝胶电泳（1-DE）、质谱分析（mass spectrometry）、蛋白水解活性、磷脂酶A2（phospholipase A2）活性、L-氨基酸氧化酶（L-amino acid oxidase）活性、血浆最小凝血剂量测定、最小出血剂量测定以及半数致死量（lethal dose 50%）测定。
结果：雌雄混合蛇毒的电泳图谱极为相似，仅存在细微的性别相关差异。雄性蛇毒的L-氨基酸氧化酶、磷脂酶A2及出血活性更高，而雌性蛇毒的凝血活性更强。另一方面，尽管部分单份样本存在个体差异，但两组混合蛇毒的蛋白水解活性未表现出统计学差异。蛋白质组图谱分析共鉴定出112种不同的蛋白质组分，其中105种为雌雄混合蛇毒所共有，另有7种为雌性蛇毒所特有。尽管存在个体差异，但两组混合蛇毒的致死活性并无显著差异。
结论：尽管本研究观测到雌雄蛇毒之间存在差异，但结果显示即使是同窝幼体，其蛇毒也存在显著的个体差异，这表明蛇毒的生物学活性与成分不仅受性别影响，还受到其他多种因素的调控。