Fig. 6

Transmission electron microscopy of Myxobolus pseudoacinosus (narrow type) from the gills of Cyprinus carpio. a Longitudinally sectioned spore showing the large polar capsule, the small polar capsule, the capsule matrix and sporoplasm. b Longitudinal section of a spore showing one polar capsule, sporoplasm and the suture line of the valves (arrowhead). Note the electron-dense granules surrounding the posterior end of the spore (white asterisks). c Detail of polar capsules showing a three-layer structure consisting of inner capsule matrix, an adjacent electron lucent zone and an outer electron-dense zone. d Transversely sectioned spore showing the large and small polar capsule. e Immature spore, note the valvogenic cell. f Ultrastructural detail of the suture line of the valves (arrowhead) and the electron-dense granules surrounding the posterior end of the spore (white asterisks). Abbreviations: CM, capsule matrix; ED, outer electron dense zone; LPC, large polar capsule; LU, adjacent electron lucent zone; PC, polar capsule; SPC, small polar capsule; Sp, sporoplasm; VC, valvogenic cell. Scale-bars: a, b, 2 μm; c-e, 1 μm: f, 500 nm