Marques Maurício Ribeiro, Mendes Maria Anita, Tormena Cláudio Francisco, Souza Bibiana M, Cesar Lílian Mari Marcondes, Rittner Roberto, Palma Mario S
Dept. Biology, CEIS, Lab. Structural Biology and Zoochemistry, Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, SP-13506-900-Brazil.
Chem Biodivers. 2005 Apr;2(4):525-34. doi: 10.1002/cbdv.200590034.
The orb-web spiders are polyphagous animals in which the web plays a very important role in the capture of preys; oily droplets usually cover the capture-web of the spider Nephila clavipes and seem to be of great importance for prey capture. The knowledge of the chemical composition of these droplets is necessary to understand the function of this adhesive material in web mechanics and prey capture. A novel subclass of spider toxins, tetrahydro-beta-carboline, was identified among the weaponry of compounds present inside of oily droplets. This type of alkaloid is not common among the natural compounds of spider toxins. Apparently, when the prey arthropods get caught by the spider web, their bodies are covered with many adhesive oily droplets, which disrupt delivering the tetrahydro-beta-carboline to the direct contact with the prey integument. Toxicity assays demonstrated a potent lethal effect of the alkaloid toxin to the spider preys; topical applications of the tetrahydro-beta-carboline at first caused clear signs of neurotoxicity, followed by the death of preys. The structure of the major component, a tetrahydro-beta-carboline, among the alkaloid toxins was elucidated by means of UV spectrophotometry, ESI mass spectrometry, 1H-NMR spectroscopy, and high-resolution mass spectrometry. The structure of the natural toxin was determined as 1-(2-guanidinoethyl)-1,2,3,4-tetrahydro-6-hydroxymethyl)-beta-carboline; the investigation of the pharmacological properties and neurotoxic actions of this compound may be used in the future as reference for the development of new drugs to be applied at level of pest control in agriculture.
圆蛛是杂食性动物，其蛛网在捕获猎物中起着非常重要的作用；油滴通常覆盖在大木林蛛的捕获网上，似乎对猎物捕获非常重要。了解这些油滴的化学成分对于理解这种粘性物质在蛛网力学和猎物捕获中的功能是必要的。在油滴内部存在的化合物武器库中鉴定出了一种新型的蜘蛛毒素亚类，即四氢-β-咔啉。这种生物碱在蜘蛛毒素的天然化合物中并不常见。显然，当猎物节肢动物被蜘蛛网捕获时，它们的身体会被许多粘性油滴覆盖，这会干扰四氢-β-咔啉与猎物外皮的直接接触。毒性试验表明，这种生物碱毒素对蜘蛛猎物具有强大的致死作用；局部应用四氢-β-咔啉首先会引起明显的神经毒性迹象，随后猎物死亡。通过紫外分光光度法、电喷雾质谱、1H-核磁共振光谱和高分辨率质谱阐明了生物碱毒素中主要成分四氢-β-咔啉的结构。天然毒素的结构确定为1-(2-胍基乙基)-1,2,3,4-四氢-6-羟甲基)-β-咔啉；对该化合物药理性质和神经毒性作用的研究未来可能作为开发用于农业害虫防治的新药参考。
