ИСТИНА

Intestine structures were studied using TEM methods in ten White Sea species including Bathylaimus arcticus, Oxystomina sp., Paracanthonchus caecus, Halichoanolaimus robustus, Desmodora communis, Draconema ophicephalum, Paramonhystera lamentosa, Sphaerolaimus balticus, Odontophora deconinki and Sabatieria ornata. Nematode intestine is a simple tube made up by a single layer of epithelial cells. Outer surface of these cells are covered by basal membrane, and apical surface of cells have microvilli, which are immersed in glycocalyx; an extracellular matrix, which may have very dierent structure. Microvilli and glycocalyx are the most diverse structures in various species. There are some correlations between microvillar layer and glycocalyx structures with feeding types of nematode and (less evident) with taxonomic position of nematode species. Predatory species and nonselective deposit feeders (feeding type 1B of Wieser, 1953) have complicated glycocalix while presumably herbivorous species (feeding type 2A) have glycocalyx as amorphous matrix and/or lamellar layer. Nematodes with intermediate glycocalyx type (lamellar, amorphous with dierent structures) belong to various feeding types. Generally, the smaller-sized nematodes (Oxystomina sp., Desmodora communis and Draconema ophicephalum) share some similar features: short and thick microvilli and amorphous glycocalyx. The study is supported by Russian Fund of Fundamental Researches, grant N 15- 04-02597