Department of Systematic Zoology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, Poznań 61-614, Poland.
Department of Animal Physiology and Development, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, Poznań 61-614, Poland.
Comp Biochem Physiol C Toxicol Pharmacol. 2018 Feb;205:43-52. doi: 10.1016/j.cbpc.2018.01.004. Epub 2018 Jan 31.
Anuran toxins released from the skin glands are involved in defence against predators and microorganisms. Secretion from parotoid macroglands of bufonid toads is a rich source of bioactive compounds with the cytotoxic, cardiotoxic and hemolytic activity. Bufadienolides are considered the most toxic components of the toad poison, whereas the protein properties are largely unknown. In the present work, we analysed the cardio-, myo-, and neurotropic activity of extract and the selected proteins from Bufo bufo parotoids in in vitro physiological bioassays carried out on two standard model organisms: beetles and frogs. Our results demonstrate a strong cardioactivity of B. bufo gland extract. The toad poison stimulates (by 16%) the contractility of the insect heart and displays the cardioinhibitory effect on the frog heartbeat frequency (a 27% decrease), coupled with an irreversible cardiac arrest. The gland extract also exhibits significant myotropic properties (a 10% decrease in the muscle contraction force), whereas its neuroactivity remains low (a 4% decrease in the nerve conduction velocity). Among identified peptides present in the B. bufo parotoid extract are serine proteases, muscle creatine kinase, phospholipid hydroperoxide glutathione peroxidase, cytotoxic T-lymphocyte protein, etc. Some proteins contribute to the cardioinhibitory effect. Certain compounds display the paralytic (myo- and neurotropic) properties. As the toad gland extract exhibits a strong cardiotoxic activity, we conclude that the poison is a potent agent capable of slaying a predator. Our results also provide the guides for the use of toad poison-peptides in therapeutics and new drug development.
蛙类皮肤腺释放的毒素参与防御捕食者和微生物。蟾蜍的腮腺分泌的物质是具有细胞毒性、心脏毒性和溶血活性的生物活性化合物的丰富来源。蟾蜍毒素中的蟾蜍内酯被认为是毒性最强的成分，而其蛋白质特性在很大程度上是未知的。在本工作中，我们在两种标准模式生物（甲虫和青蛙）上进行的体外生理生物测定中，分析了 Bufo bufo 腮腺提取物和选定蛋白质的心脏、肌肉和神经毒性活性。我们的结果表明，B. bufo 腺体提取物具有很强的心脏毒性。蟾蜍毒素刺激（增加 16%）昆虫心脏的收缩力，并对青蛙心跳频率显示出心脏抑制作用（降低 27%），同时伴有不可逆的心脏骤停。腺体提取物还表现出显著的肌肉毒性特性（肌肉收缩力降低 10%），而其神经毒性保持较低（神经传导速度降低 4%）。在 B. bufo 腮腺提取物中鉴定出的肽包括丝氨酸蛋白酶、肌肉肌酸激酶、磷脂氢过氧化物谷胱甘肽过氧化物酶、细胞毒性 T 淋巴细胞蛋白等。一些蛋白质有助于心脏抑制作用。某些化合物具有麻痹（肌肉和神经毒性）特性。由于蟾蜍腺体提取物具有很强的心脏毒性活性，我们得出结论，这种毒液是一种能够杀死捕食者的有效物质。我们的结果还为蟾蜍毒素肽在治疗和新药开发中的应用提供了指导。
