Cavalcante Ingrid Duarte, Antoniazzi Marta Maria, Jared Carlos, Pires Osmindo R, Sciani Juliana Mozer, Pimenta Daniel Carvalho
Laboratório de Bioquímica e Biofísica, Instituto Butantan, São Paulo, SP, 05503-900 Brazil.
Laboratório de Biologia Celular, Instituto Butantan, São Paulo, SP, 05503-900, Brazil.
Toxicon. 2017 May;130:127-135. doi: 10.1016/j.toxicon.2017.02.028. Epub 2017 Feb 27.
Dermatonotus muelleri is the sole species of the Dermatonotus genus and inhabits Argentina, Bolivia, Brazil and Paraguay. This animal exhibits an explosive reproductive behavior during the Southern spring months, which lasts only for five days. Moreover, this animal displays specific adaptations to the habitat resulting in the energy conservation needed during either the intense reproduction period or times of estivation. During dry seasons and/or food shortages D. muelleri can survive because its food specialization and ability to dig an underground chamber for protection. Few literature is available on this amphibian and no biochemical characterization has ever been performed on the animal's skin secretion. This work, on the other hand, presents for the first time a venomic analysis of the major components present in the skin secretion of this microhylid. The crude skin secretion was obtained my mechanical stimulation and was analyzed according to one major criterion: >10 kDa or <10 kDa. The high molecular mass fraction was subjected to typical gel-based proteomic processing whereas the low molecular mass fraction was analyzed by liquid chromatography, mass spectrometry and nuclear magnetic resonance (NMR), yielding an overall 'venomics' approach. No classical/evident toxin was detected, but peptidases (metallo and serino) and structural proteins could be identified. In the low molecular mass fraction no peptides were detected, as well as no typical alkaloid or steroid. On the other hand, the amino acid tryptophan could be identified and a typical sugar spectrum was obtained in the NMR analyses. Altogether these findings point out to the fact that D. muelleri skin secretion is unique and the molecular arsenal present herein is yet to be explored; therefore, this venomics study is only the beginning.
穆氏皮蛙是皮蛙属的唯一物种，栖息于阿根廷、玻利维亚、巴西和巴拉圭。这种动物在南半球春季的几个月里会表现出爆发性繁殖行为，仅持续五天。此外，这种动物对栖息地有特定的适应性，从而在繁殖旺盛期或夏眠期间能够保存所需能量。在旱季和/或食物短缺时，穆氏皮蛙能够存活，因为它的食物具有专一性，并且有挖掘地下洞穴进行自我保护的能力。关于这种两栖动物的文献很少，而且从未对其皮肤分泌物进行过生化特性分析。另一方面，这项研究首次对这种姬蛙科动物皮肤分泌物中的主要成分进行了毒液组分析。通过机械刺激获取粗皮肤分泌物，并根据一个主要标准进行分析：分子量>10 kDa或<10 kDa。高分子量部分进行了典型的基于凝胶的蛋白质组学处理，而低分子量部分则通过液相色谱、质谱和核磁共振（NMR）进行分析，形成了一种全面的“毒液组学”方法。未检测到经典/明显的毒素，但可鉴定出肽酶（金属肽酶和丝氨酸肽酶）和结构蛋白。在低分子量部分未检测到肽，也未检测到典型的生物碱或类固醇。另一方面，可鉴定出氨基酸色氨酸，并且在核磁共振分析中获得了典型的糖谱。这些发现共同表明，穆氏皮蛙的皮肤分泌物具有独特性，其中的分子库有待进一步探索；因此，这项毒液组学研究仅仅是一个开始。
