Interrelationships of cytoplasmic structures in Bonamia sp. (Haplosporidia) infecting oysters Tiostrea chilensis: an interpretation

Ultrastructural observations on structures associated with the 'haplosporosome'-like electron-dense bodies (EDBs) of the primary cell of the extrasporogonic stage of PKX are descr~bed. Observations made include formation of EDBs by the trans-Golgi network, an additional membrane associated with EDB structure, confronting cisternae, engulfment and presence of EDBs in multivesicular bodies, fusion of EDBs with the plasmalemma, degeneration of EDBs in disintegrating primary cells and endocytosis of PKX cytoplasm by adherent macrophages. lmmunogold localisation of a PKXspecific monoclonal antibody (hdAb A3) suggests that the EDBs contain periodate-sensitive carbohydrates on their membranes. Tissues prepared for irnrnunogold electron microscopy further suggest that some contain a lipid-rich core. An interpretation is made on their possible function and their relationship with the haplosporosornes and sporoplasrnasomes found in members of the Haplosporidea and Myxosporea respectively.

Section: Discussionmentioning

confidence: 99%

“…This cytoplasmic structure resembled an unidentified surface projection described previously in Bonamia sp. by Hine & Wesney (1992). EDBs appeared to be released from the primary cell into the intrac6llular space in areas where the par- Interdigitating of primary cell of extrasporogonic PKX with macrophage (*).…”

Section: Plasmalemma and Associated Macrophagesmentioning

confidence: 99%

Observations on the electron-dense bodies of the PKX parasite, agent of proliferative kidney disease in salmonids

Morris¹,

Adams²,

Richards³

2000

“…20. 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.…”

Section: Discussionmentioning

confidence: 99%

“…In vegetative stages, haplosporogenesis may involve production of haplosporosome-like bodies (HLBs) or haplosporosomes from NBG , from unattached Golgi in the cytoplasm (Hine & Wesney 1992), or, as in Haplosporidium nelsoni, from cytoplasmic granular masses (Perkins 1968(Perkins , 1979, possibly originating from the nucleoplasm. Similarly, in sporogenesis, haplosporosomes may be formed from DVS (Hine & Thorne 2002), or granular matter originating from the spherulosome (Hine & Thorne 1998), or directly from the spherulosome (Azevedo & Corral 1987).…”

Section: Discussionmentioning

confidence: 99%

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

Stentiford¹,

Feist²,

Bateman³

et al. 2004

Self Cite

A protozoan parasite with some features of haplosporidians is described from the European shore crab Carcinus maenas. The parasite establishes a systemic infection through the haemal sinuses and connective tissues. Intracellular stages of the parasite were found within reserve inclusion, connective tissue, and muscle cells, while free forms were present in all haemal spaces. A uninucleate stage appeared to develop to a multinucleate plasmodial stage following multiple mitotic divisions of the nucleus. Histopathology also indicated that nuclear division may occur to form multinucleate plasmodia, in connective tissue, reserve inclusion and muscle cells, the multinucleate plasmodium being enclosed in the host-cell plasma membrane. It appears that the multinucleate plasmodium may then undergo internal cleavages which result in plasmodial fragmentation to form many uninucleate stages. Both stages, but particularly the uninucleate stage, contained cytoplasmic, large, ovoid, dense vesicles (DVs), some of which contained an internal membrane separating the medulla from the cortex, as in haplosporosomes. Golgi-like cisternae, closely associated with the nuclear membrane, formed DVs and haplosporosome-like bodies (HLBs), superficially resembling viruses. Infrequently, HLBs may condense to form haplosporosomes. The DVs, as in spores of some Haplosporidium spp. and paramyxeans, may give rise to, and are homologous with, haplosporosomes. Other features, such as the presence of an intranuclear mitotic spindle, lipid droplets, and attachment of DVs and haplosporosomes to the nuclear membrane, indicate that the C. maenas parasite is a haplosporidian. A similar organism reported from the haemolymph of spot prawns Pandalus spp., and haplosporidians reported from prawns Penaeus vannamei and crabs Callinectes sapidus may belong to this group. It is concluded that the well-characterised haplosporidians of molluscs and some other invertebrates may not be characteristic of the whole phylum, and that morphologically and developmentally similar organisms may also be haplosporidians, whether they have haplosporosomes or not.

“…Bonamia exitiosus, morphologically similar to B. ostreae, is pathogenic to the dredge oyster Ostrea chilensis in New Zealand (Hine 1991, Hine et al 2001. Both species of Bonamia were tentatively considered haplosporidians despite the apparent absence of sporulation during their life cycles (Pichot et al 1980, Hine & Wesney 1992, Hine et al 2001) and molecular evidence has recently confirmed their inclusion in the phylum Haplosporidia (Carnegie et al 2000.Histological examination of cultured abalone from a New Zealand aquaculture facility experiencing mortalities suggested the presence of a haplosporidian parasite, although no spores were observed . Molecular genetic analysis was performed using SSU rDNA obtained from infected abalone to further characterize this organism.…”

mentioning

confidence: 99%

Molecular analysis of a haplosporidian parasite from cultured New Zealand abalone Haliotis iris

Reece

Stokes²

2003

In the Austral summer and autumn of 2000 and 2001, mortalities of black-footed abalone Haliotis iris (Martyn, 1784) occurred in a commercial facility in New Zealand. Histological analyses suggested that infection by a haplosporidian parasite was responsible. To confirm identification as a haplosporidian and to help determine if this parasite represented a new, undescribed species, DNA was extracted from infected host tissues scored as positive for infection by histological examination. Small-subunit rRNA (SSU rRNA) gene sequences from both the host abalone and a parasitic organism were amplified by PCR and characterized. Although the sequence for this parasite was novel, not matching any known SSU rRNA gene sequences, phylogenetic analyses strongly supported grouping this parasite with the haplosporidians. Parsimony analyses placed the parasite at the base of the phylum Haplosporidia, ancestral to Urosporidium crescens and the Haplosporidium, Bonamia, and Minchinia species. Sequencing of multiple parasite DNA clones revealed a single polymorphic site in the haplosporidian SSU rRNA gene sequence.KEY WORDS: Haplosporidian · Abalone · SSU rDNA · Parasite · Molecular phylogenetic Resale or republication not permitted without written consent of the publisherDis Aquat Org 53: [61][62][63][64][65][66] 2003 ease, is morphologically similar to H. nelsoni and has been responsible for mortalities of eastern oysters in seaside embayments of the US mid-Atlantic coast (Andrews et al. 1962). Bonamia ostreae, pathogenic in the European flat oyster Ostrea edulis, has devastated the flat oyster industry in Western Europe. Katkansky et al. (1969) reported a 'microcell' parasite that resembled B. ostreae in O. edulis from California. Elston et al. (1986) later traced B. ostreae in France to importation of oysters from California. More recently, this parasite was also found on the east coast of the United States (Friedman & Perkins 1994), presumably by introductions of infected O. edulis from the west coast. Bonamia exitiosus, morphologically similar to B. ostreae, is pathogenic to the dredge oyster Ostrea chilensis in New Zealand (Hine 1991, Hine et al. 2001. Both species of Bonamia were tentatively considered haplosporidians despite the apparent absence of sporulation during their life cycles (Pichot et al. 1980, Hine & Wesney 1992, Hine et al. 2001) and molecular evidence has recently confirmed their inclusion in the phylum Haplosporidia (Carnegie et al. 2000.Histological examination of cultured abalone from a New Zealand aquaculture facility experiencing mortalities suggested the presence of a haplosporidian parasite, although no spores were observed . Molecular genetic analysis was performed using SSU rDNA obtained from infected abalone to further characterize this organism. MATERIALS AND METHODSDNA isolation and PCR amplification. DNA was isolated from epipodium tissue of 5 infected Haliotis iris individuals (2 animals received in September 2000 and 3 animals received in February 2001) using the protocol for anim...