Etges F J, Marinakis V
Department of Biological Sciences, University of Cincinnati, Ohio 45221.
J Parasitol. 1991 Aug;77(4):595-602.
The function of calcareous bodies, commonly found in the parenchyma of cestodes and trematodes, is relatively poorly understood. The present histochemical ultrastructural study of the proliferative tetrathyridia of Mesocestoides vogae revealed that calcareous corpuscles begin to form as organic (lipid-protein) masses that coalesce in parenchymal (calcareogenic) cells. Concentric accretion of organic and inorganic crystalline material then leads to the formation of typical refractile calcareous bodies. The precise composition of such bodies, determined by x-ray diffraction, revealed that their major inorganic constituent is indeed calcium, with significant amounts of phosphorus, silicon, and zinc as well. Emission of calcareous bodies through the tegument was observed by scanning electron microscopy, explaining their accumulation in the intracapsular spaces around worms embedded in liver tissue of the host. Following their emission, the crystalline substance of corpuscles dissolves, leaving only nonrefractile, membrane-bound cytoplasmic debris. These observations do not preclude the possibility that calcareous bodies may play some role as buffers or reservoirs of inorganic ions. However, it is difficult to accept such a function for unencapsulated worms in the coelom or intestinal lumen; we suggest that excretion is a more likely role in such sites.
通常在绦虫和吸虫实质中发现的石灰小体的功能相对了解较少。目前对沃氏中绦虫增殖性四盘蚴的组织化学超微结构研究表明，石灰小体开始形成时是在实质（生钙）细胞中融合的有机（脂质 - 蛋白质）团块。然后有机和无机晶体物质的同心堆积导致典型的折光性石灰小体形成。通过X射线衍射确定的这些小体的精确组成表明，其主要无机成分确实是钙，还有大量的磷、硅和锌。通过扫描电子显微镜观察到石灰小体通过皮层排出，这解释了它们在宿主肝组织中嵌入的蠕虫周围囊内空间中的积累。排出后，小体的晶体物质溶解，仅留下无折光性的、膜结合的细胞质碎片。这些观察结果并不排除石灰小体可能作为无机离子的缓冲剂或储存库发挥某些作用的可能性。然而，对于体腔或肠腔中未被包囊的蠕虫来说，很难接受这样的功能；我们认为在这些部位排泄是更有可能的作用。
