Fedyaeva M.A., Tchesunov A.V. 2017. Fine structure of midgut cells of some White Sea free-living nematodes // Invertebrate Zoology. Vol.14. No.1: 8–13 [in English].
Department of Invertebrate Zoology, Faculty of Biology, Lomonosov Moscow State University, Leninskiye Gory 1-12, Moscow, 119991 Russia. E-mail: email@example.com
ABSTRACT: Midgut of nematodes is a straight tube consisting of a single layer of epithelial cells lined by layer of microvilli, which are covered by a glycocalyx. There are usual organelles in cells: nuclei, mitochondria, digestive vacuoles, endoplasmic reticulum, Golgi complexes. Gut cells of different nematode species could vary widely. We studied ten species of White Sea nematodes: Bathylaimus arcticus Kreis, 1963, Oxystomina sp., Paracanthonchus caecus Micoletzky, 1924, Halichoanolaimus robustus (Bastian, 1865), Desmodora communis (Bütschli, 1874), Draconema ophicephalum (Claparède, 1863), Paramonhystera filamentosa (Ditlevsen, 1928), Sphaerolaimus balticus Schneider, 1906, Odontophora deconinki Galtsova, 1976 and Sabatieria ornata (Ditlevsen, 1918). Almost all organelles have some their own features in the cells for each species. Some organelles seem to be dependent on the stage of food digestion, while others have been associated with a taxonomic position or with a food object. In cells of all species small digestive vacuoles are observed, but some species have big ones. They can be created by fusion of small digestive and enzyme vacuoles. Lipid droplets are indicated in cells of almost all species. Quantity of these droplets can be depending on digestive stage. Microvilli and glycocalyx do not have a clean connection either with the type of food, or with the taxonomic position of the nematodes. But if glycocalyx is complex we can see correlation with taxonomic position of nematodes: similar type of glycocalyx and microvilli are observed for nematodes from one order.
KEY WORDS: Nematoda, White Sea, midgut, ultrastructure.