Sporogenesis of the myxosporean Kudoa paniformis Kabata & Whitaker, 1981 infecting the muscle of the Pacific whiting, Merluccius productus (Ayres)

Abstract

Abstract. This ultrastructural study examines Sporogenesis of Kudoa paniformis, a monosporous myxosporean that causes a softened muscle texture in cooked Pacific whiting, Merluccius productus. Capsulogenesis and valvogenesis occur in a manner similar to that of other myxosporeans, while some aspects of generative cell interaction and sporoplasm ultrastructure differ from most other myxosporeans that have been examined with electron microscopy. Capsulogenesis of K. paniformis includes the formation of an external tubule which is continuous with the polar capsule, followed by the apparent internalization and modification of the external tubule to form a polar filament winding within the polar capsule. Valvogenesis occurs with the accumulation of electron‐dense material on the cytoplasmic side of the outer membrane of each valvogenic cell to form a valve wall, Sporogenesis of K. paniformis differs from other myxosporeans in two aspects: (1) spore development does not appear to begin as a result of one generative cell engulfing another, and (2) the sporoplasm of developing and mature spores contains two morphologically distinct cells, one of which surrounds the other.