Ultrastructural study on peripheral blood erythrocytes and thrombocytes in skewband grunt (Hapalogenys nitens)
斜带髭鲷外周血红细胞和血栓细胞的超微结构

The aim of the present paper was first to examine the peripheral blood erythrocytes and thrombocytes in skewband grunt (Hapalogenys nitens) by transmission electron microscopic method and second to characterize them ultrastructurally. Subsequent study showed that erythrocytes were oval or elongated ellipsoidal cells with a central, oval nucleus with heterochromatin blocks. A few dividing or divided nuclei appeared in the cells. Scarce organelles such as some mitochondria, polyribosomes, small vesicles and an occasional small Golgi complex were found in the cytoplasm. A marginal band of microtubules was presented beneath the plasmalemma. Some apoptotic red blood cells were also seen. On the electron micrographs, thrombocytes were variable in form with short pseudopodia, long filopodia or no protrusion. The nucleus exhibited the characteristics of large heterochromatin blocks or networks. Organelles such as free ribosomes and microtubules were abundant, rough endoplasmic reticulum, mitochondria, electrondense granules and largr vesicles were scarce. The surface-connected canalicular system (SCCS) formed by numerous vacuoles and canaliculi of different sizes and shapes has a distinguishing feature of thrombocytes and distributed throughout the cytoplasm. Meanwhile, the phagocytosis of thrombocytes was described. And the phagocytic ability of piscine thrombocytes was also discussed in this paper.