engleski

The unusual design of a usual organ - The curious case of Anisakis spp. gland cell

Background and aims: Nematodes of the genus Anisakis are parasites of marine organisms, being able to cause disease in humans (anisakiasis). A characteristic feature of these worms is the excretory gland cell (EGC), a single large cell essential for worms’ metabolism and pathogenicity. Previous studies on third-stage larvae (L3) have found an unusually large nucleus with spike-like cytoplasmic protrusions. Therefore, the objective of this study was to perform electron and light microscopy studies to determine the spatial organization of this cell. Methods: For electron microscopy, EGCs were stained by the OTO method, embedded in resin and trimmed to the appropriate size. Images were acquired using Apreo SEM equipped with Volume Scope. Segmentation was done in Microscopy Image Browser and Amira was used for 3D visualisations. For light microscopy, cells were stained with Phalloidin iFluor 488 and DAPI and observed under Olympus Fluoview confocal microscope. Images were modelled using IMARIS software Results: The nuclear envelope is rich in nuclear pore complexes and pleated with large blebs, protruding into the nuclear lumen. The main excretory channel is slightly curved, but generally follows the main axis of the cell. Numerous minor collecting ducts radiate from the main channel into the cytoplasm. Light microscopy showed an intricate network of actin filaments corresponding to collecting ducts seen in electron microscopy images. In addition, a mesh-like appearance of chromatin was found with several foci of more condensed chromatin. Conclusions: The EGC of Anisakis is an interesting example of a single cell organ with an unusually large nucleus compared to other metazoans, whose spatial organization likely plays a functional role.

Anisakis ; anisakiasis ; gland cell ; nucleus ; electron microscopy

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