Brázová Tímea, Poddubnaya Larisa G, Miss Noemí Ramírez, Hanzelová Vladimíra
Folia Parasitol (Praha). 2014 Dec;61(6):549-57.
The ultrastructure and chemical composition of the proboscis hooks and surrounding tegument of Acanthocephalus lucii (Müller, 1776), a parasite of European perch, Perca fluviatilis Linnaeus, were examined using scanning (SEM) and transmission (TEM) electron microscopy and X-ray microanalysis (EDXA). The blade of middle hooks consists of three layers: an outer homogeneous layer, an inner heterogeneous layer and a central core. TEM observation revealed the presence of hollow tubes, which spaced the central core; fibrous inner hook layer surrounded by an electron-dense margin and the basal tegumental layer filled with electron-dense bodies and outer layer. We found for the first time that the so-called 'epidermal covering' surrounding of the exposed hook blade (outer hook layer) is a modified striped portion of the tegumental layer and there are no special contact sites between these two morphologically different structures, i.e. striped layer of the syncytial tegument and following proper outer hook layer, which is a homogeneous, moderately electron-dense layer of -0.3 μm in thickness. The hook root is embedded into subtegumental fibrous layer. X-ray microanalysis of both the surface and internal parts of A. lucii hooks demonstrated the presence of calcium, magnesium, phosphorus and sulphur. The highest concentration of sulphur was recorded at the tip of hooks, whereas the middle part of the hooks was most rich in calcium, phosphorus and magnesium. The proximal part of the hooks contained lower concentrations of sulphur, calcium and phosphorus. In the proboscis tegument, only two elements, calcium and silicon, were found. The differences observed in the chemical composition of the hook 'epidermal covering' and the proboscis tegument support our ultrastructural findings that the hook tegumental covering is a modified structure compared with that of the general proboscis tegument.
利用扫描电子显微镜（SEM）、透射电子显微镜（TEM）和X射线微分析（EDXA），对欧洲鲈（Perca fluviatilis Linnaeus）的寄生虫——鲁氏棘头虫（Acanthocephalus lucii，Müller，1776）的吻钩及其周围皮层的超微结构和化学成分进行了研究。中间钩的钩刃由三层组成：外层均质层、内层非均质层和中央核心。透射电镜观察显示存在中空管，其将中央核心隔开；纤维状的内钩层被电子致密边缘包围，基部皮层充满电子致密体和外层。我们首次发现，暴露的钩刃（外钩层）周围所谓的“表皮覆盖物”是皮层的一个经过修饰的条纹部分，这两个形态不同的结构之间没有特殊的接触位点，即合胞体皮层的条纹层和随后的合适外钩层，外钩层是一个厚度为0.3μm的均质、中等电子致密层。钩根嵌入皮层下纤维层。对鲁氏棘头虫吻钩的表面和内部进行X射线微分析，结果表明存在钙、镁、磷和硫。在钩尖处记录到最高浓度的硫，而钩的中部钙、磷和镁含量最丰富。钩的近端部分硫、钙和磷的浓度较低。在吻皮层中，仅发现钙和硅两种元素。在钩“表皮覆盖物”和吻皮层的化学成分上观察到的差异，支持了我们的超微结构研究结果，即钩皮层覆盖物与一般吻皮层相比是一种经过修饰的结构。
