Abstract:
Dibothriocephalus ditremus and Dibothriocephalus latus are diphyllobothriidean tapeworms autochthonous to Europe. Their larval stages (plerocercoids) may seriously alter health of their intermediate fish hosts (D. ditremus) or cause intestinal diphyllobothriosis of the final human host (D. latus). Despite numerous data on the internal structure of broad tapeworms, many aspects of the morphology and physiology related to host–parasite co-existence remain unclear for these 2 species. The main objective of this work was to elucidate functional morphology of the frontal part (scolex) of plerocercoids, which is crucial for their establishment in fish tissues and for an early attachment in final hosts. The whole-mount specimens were labelled with different antibodies and examined by confocal microscope to capture their complex 3-dimensional microanatomy. Both species exhibited similar general pattern of immunofluorescent signal, although some differences were observed. In the nervous system, FMRF amide-like immunoreactivity (IR) occurred in the bi-lobed brain, 2 main nerve cords and surrounding nerve plexuses. Differences between the species were found in the structure of the brain commissures and the size of the sensilla. Synapsin IR examined in D. ditremus occurred mainly around FMRF amide-like IR brain lobes and main cords. The unexpected finding was an occurrence of FMRF amide-like IR in terminal reservoirs of secretory gland ducts and excretory canals, which has not been observed previously in any tapeworm species. This may indicate that secretory/excretory products, which play a key role in host–parasite relationships, are likely to contain FMRF amide-related peptide/s.
摘要:
双头鱼和双头鱼是自生于欧洲的双头虫。它们的幼体阶段(plerocercoids)可能会严重改变其中间鱼类宿主的健康状况(D.ditremus)或引起最终人类宿主的肠道二苯基病(D.latus)。尽管有大量关于广泛的tape虫内部结构的数据,对于这两种物种,与宿主-寄生虫共存相关的形态学和生理学的许多方面仍不清楚。这项工作的主要目的是阐明plerocercoids的额叶部分(scolex)的功能形态,这对于它们在鱼类组织中的建立以及在最终宿主中的早期附着至关重要。用不同的抗体标记完整的标本,并通过共聚焦显微镜检查以捕获其复杂的三维显微解剖结构。两种物种表现出相似的免疫荧光信号的一般模式,尽管观察到了一些差异。在神经系统中,FMRF酰胺样免疫反应性(IR)发生在双叶脑中,2主神经索和周围神经丛。在大脑连合的结构和感官的大小方面发现了物种之间的差异。在D.ditremus中检查的突触蛋白IR主要发生在FMRF酰胺样IR脑叶和主干周围。出乎意料的发现是在分泌腺管和排泄管的末端水库中发生了FMRF酰胺样IR,以前在任何tape虫物种中都没有观察到。这可能表明分泌/排泄产物,在宿主-寄生虫关系中起着关键作用,可能含有FMRF酰胺相关肽。