Figure 6

Ultrastructure of developmental stages of D. roeselum from Gammarus balcanicus (A–F) and D. duebenum from Echinogammarus berilloni (G–K). (A) Oblique section of merozoite showing two attached nuclei (nu) and homogenously granular cytoplasm. (B) Diplokaryotic presporont with cytoplasm containing numerous cysternae of the endoplasmic reticulum. The cell is coated with electron dense material. (C) Sporophorous vesicle (sv) with divided sporogonal plasmodium. Episporontal space contains not numerous tubules (arrow) and granular substance. (E) Sporophorous vesicle (sv) with separated late sporoblasts, rare microtubules (arrow) and aggregated granules. (F) Part of mature spores showing eight coils of isofilar polar filament (pf). (G) Part of sporophorous vesicle with rare inclusions. Divided and separated sporoblasts (sb) are visible. (H) Early merozoite, late merogonal stages (presporont) and sporophorous vesicles (sv) containing late sporoblasts are presented. The presporont is arrowed. (J) Sporophorous vesicle with immature spores (arrow) and rare loosely packed inclusions are presented. The dense Golgi-derived substance fills the core of the polar filament and forms a large globe shaped inclusion. (K) Section through the posterior part of mature uninucleate spore. Polar filament (pf), posterior vacuole (pv) and spore wall ultrastructure with exospore (e) and endospore (en) are visible. Sporophorous vesicle contains rare tubules 70–100 nm in diameter and eletron dense filaments 40–50 nm in thickness. Scale bars: 100 nm (B); 300 nm (A,F); 800 nm (K); 1.2 µm (C,E,G,J); 1.5 µm (H).