The functional cytology of Bonamia sp. (Haplosporidia) infecting oysters Tiostrea chilensis:an ultracytochemical study

Abstract

Bonamia sp., a serious pathogen of oysters Tiostrea chilensis, was studied using the zinc iodide-osmium tetroxide technique (ZIO), the imidazole-osmium technique for lipids (IM), and reactivity for acid phosphatases [P-glycerophosphatase (P-GPase), cytidine monophosphatase at pH 5.0 (CMPase 5.0) and pH 2.7 (CMPase 2.7), thiamine pyrophosphatase (TPPase)], and P-galactosidase to try and determine the function of cytoplasmic organelles. Z10 reacted with the nuclear membrane, Golgi, endoplasmic reticulum (ER), cytoplasmic vesicles, and variably with putative phagosomes, the mitochondrial matrix, haplosporosomes and multivesicular bodies, but not lipoid bodies. IM strongly labelled lipoid bodies, and lipids in the nuclear membrane, ER except anastomosing ER (aER) and mitochondrial membranes and cristae, but was weak in aER and on haplosporosomes. P-GPase occurred in the nuclear membrane, some elements of ER, Golgi and mitochondrla, and in lipoid bodies. CMPase 5.0 was variable in Golgi and ER, but was stronger at pH 2.7 and occurred in the nuclear membrane. TPPase only occurred in a single Golgi cisterna, or very weakly in a few lipoid bodies. P-galactosidase was rarely seen, and only within Golgi. As there was considerable metabolism of unsaturated lipids and little hydrolytic enzyme content, it was concluded that Bonarnla sp. may synthesise lipids from triglycerides hydrolysed by haemocyte enzymes, reducing the need for parasite hydrolytic enzymes.

Haemolymph parasite of the shore crab Carcinus maenas: pathology, ultrastructure and observations on crustacean haplosporidians

“…The inclusion bodies in H. ascidiarum (Ormières & de Puytorac 1968, Ciancio et al 1999) may also correspond to DVs, but their association with surrounding ER is similar to that seen around lipid droplets in Bonamia exitiosa (= Bonamia sp.) (Hine & Wesney 1994). However, they are also closely associated with the spherulosome, as are DVs, so their identity is unclear.…”

“…Haemocyte containing extensive membranous whorls; uninucleate stages of parasites can be seen in various states of degeneration within these whorls (arrows); scale bar = 2 µm 1975b), and granular material may lie in pits on the nuclear surface (Perkins 1969, Hine & Wesney 1992. Cytoplasmic organelles include lipid droplets (Hine & Wesney 1994), sparse endoplasmic reticulum (ER) and ribosomes, haplosporosomes or homologous structures, and nuclear membrane-bound Golgi (NBG) (Perkins 1979, Hine & Wesney 1992.…”

Bonamia exitiosus n.sp. (Haplosporidia) infecting flat oysters Ostrea chilensis in New Zealand

“…The reticulated structure (Hine & Wesney 1992), which may be connected to anastomosing endoplasmic reticulum (Hine & Wesney 1994a), and the Golgi associated with lipoid body genesis (Hine & Wesney 1994a) have not been described in B. ostreae. However, the cylindrical confronting cister- Tetra-nucleate plasmodia were rare in this study, but multi-nucleated and diplokaryotic plasmodia appear more developed in Bonamia ostreae (Brehélin et al 1982), particularly if the stages observed by Bonami et al (1985) are those of B. ostreae.…”

“…(Hine 1991a,b, Hine & Wesney 1994a, Mikrocytos spp. (Farley et al 1988), and haplosporosome-bearing parasites of crabs (Newman et al 1976) and shrimps (Dykovå et al 1988) has been regarded as uncertain as they lack a known spore stage and, on this basis, Bonamia spp.…”

“…Also, none of the early stages of haplosporidian sporulation, such as loss of haplosporosomes, thickening of the plasmodial wall and formation of a syncytium, have been reported from Bonamia sp. (Hine 1991b, 1992, Hine & Wesney 1992, 1994a or B. ostreae (Pichot et al 1979, Brehélin et al 1982, Bonami et al 1985, Grizel 1985, Perkins 1988, 1989. …”