PDF(Pubmed)
Abstract：
Nemerteans, or ribbon worms, possess tetrodotoxin and its analogues (TTXs), neurotoxins of bacterial origin, which they presumably use for capturing prey and self-defense. Most TTXs-containing nemertean species have low levels of these toxins and, therefore, have usually been neglected in studies of TTXs functions and accumulation. In the present study, Kulikovia alborostrata and K. manchenkoi, two closely related species, were analyzed for TTXs distribution in the body using the HPLC-MS/MS and fluorescence microscopy methods. The abundance of TTXs-positive cells was determined in the proboscis, integument, and digestive system epithelium. As a result, six TTXs-positive cell types were identified in each species; however, only four were common. Moreover, the proportions of the toxins in different body parts were estimated. According to the HPLC-MS/MS analysis, the TTXs concentrations in K. alborostrata varied from 0.91 ng/g in the proboscis to 5.52 ng/g in the precerebral region; in K. manchenkoi, the concentrations ranged from 7.47 ng/g in the proboscis to 72.32 ng/g in the posterior body region. The differences observed between the two nemerteans in the distribution of the TTXs were consistent with the differences in the localization of TTXs-positive cells. In addition, TTXs-positive glandular cell types were found in the intestine and characterized for the first time. TTXs in the new cell types were assumed to play a unique physiological role for nemerteans.
摘要：
Nemerteans,或者丝带蠕虫，拥有河豚毒素及其类似物（TTXs），细菌来源的神经毒素，他们大概用来捕获猎物和自卫。大多数含TTXs的nemertean物种的这些毒素含量较低，因此,在TTXs功能和积累的研究中通常被忽视。在本研究中,Kulikoviaalborostrata和K.manchenkoi，两个密切相关的物种，使用HPLC-MS/MS和荧光显微镜方法分析体内的TTXs分布。TTXs阳性细胞的丰度在鼻，长存,和消化系统上皮。因此,在每个物种中鉴定出六种TTXs阳性细胞类型；然而，只有四个是常见的。此外，估计了毒素在不同身体部位的比例。根据HPLC-MS/MS分析,K.alborostrata中的TTXs浓度从鼻的0.91ng/g到脑前区域的5.52ng/g不等；在K.manchenkoi，浓度范围从7.47ng/g到72.32ng/g在鼻后部。两种nemerteans在TTXs分布中观察到的差异与TTXs阳性细胞定位的差异一致。此外,在肠道中发现了TTXs阳性腺细胞类型，并首次进行了表征。假定新细胞类型中的TTXs对nemerteans具有独特的生理作用。
