A Possible Life Cycle for Bonamia ostreae on the Basis of Electron Microscopy Studies

Montes, Jaime; Anadón, Ricardo; Azevedo, Carlos

doi:10.1006/jipa.1994.1001

Cited by 41 publications

(26 citation statements)

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“…infects gill epithelial cells and haemocytes, causes gill lesions, and a relatively small number of these parasites are capable of causing severe disease. B. ostreae is intermediate in that it infects both haemocytes and epithelial cells, it causes gill lesions, but only heavy parasite burdens are associated with disease (Comps et al 1980, Pichot et al 1980, Balouet et al 1983, Montes et al 1994. Absence of gill lesions in B. exitiosus-infected T. chilensis may be due to lack of infection of gill epithelium or to the greater collagen content of T. chilensis gills compared to other Tiostrea species; this in turn may be related to the long larval brooding period of 3 wk between the gills (Hine 1991, Hine & Wesney 1994a.…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have included observations of the ultrastructure of Bonamia ostreae (Comps et al 1980, Pichot et al 1980, Bréhelin et al 1982, Grizel et al 1983, Grizel 1985, Chagot et al 1992, Montes et al 1994 and B. exitiosus (Dinamani et al 1987, Hine 1991, Hine & Wesney 1994a,b, Hine et al 2001b), but there are none on Bonamia sp. in Ostrea angasi in Australia or Tiostrea chilensis in Chile.…”

Section: Introductionmentioning

confidence: 99%

“…cannot be distinguished solely by the hosts which they infect. However, to date the geographic distributions of the 2 Mikrocytos species appear to be distinct, with M. mackini having been reported only in western Canada and M. roughleyi only in eastern Australia.Several studies have included observations of the ultrastructure of Bonamia ostreae (Comps et al 1980, Pichot et al 1980, Bréhelin et al 1982, Grizel et al 1983, Grizel 1985, Chagot et al 1992, Montes et al 1994 and B. exitiosus (Dinamani et al 1987, Hine 1991, Hine & Wesney 1994a,b, Hine et al 2001b), but there are none on Bonamia sp. in Ostrea angasi in Australia or Tiostrea chilensis in Chile.…”

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Mikrocytos roughleyi taxonomic affiliation leads to the genus Bonamia (Haplosporidia)

Cochennec-Laureau¹,

Reece²,

Berthe³

et al. 2003

Dis. Aquat. Org.

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Microcell-type parasites of oysters are associated with a complex of diseases in different oyster species around the world. The etiological agents are protists of very small size that are very difficult to characterize taxonomically. Associated lesions may vary according to the host species, and their occurrence may be related to variations in tissue structure. Lesion morphology cannot be used to distinguish the different agents involved. Ultrastructural observations on Mikrocytos roughleyi revealed similarities with Bonamia spp., particularly in regard to the presence of electron-dense haplosporosomes and mitochondria, whose absence from M. mackini also indicate that M. roughleyi and M. mackini are not congeneric. A partial small subunit (ssu) rRNA gene sequence of M. roughleyi was determined. This partial sequence, 951 nucleotides in length, has 95.2 and 98.4% sequence similarities with B. ostreae and B. exitiosus ssu rDNA sequences, respectively. Polymorphisms among the ssu rDNA sequences of B. ostreae, B. exitiosus and M. roughleyi allowed identification of restriction enzyme digestion patterns diagnostic for each species. Phylogenetic analysis based on the ssu rDNA data suggested that M. roughleyi belongs in the phylum Haplosporidia and that it is closely related to Bonamia spp. On the basis of ultrastructural and molecular considerations, M. roughleyi should be considered a putative member of the genus Bonamia.KEY WORDS: Mikrocytos roughleyi · Saccostrea glomerata · Bonamiosis · Microcell · Taxonomy · Small subunit rDNA Resale or republication not permitted without written consent of the publisherDis Aquat Org 54: [209][210][211][212][213][214][215][216][217] 2003 Farley et al. 1988), and M. roughleyi causes winter mortality in the Sydney rock oyster Saccostrea glomerata in SE Australia (Roughley 1926, Farley et al. 1988). Experimentally, Bonamia spp. can infect Ostrea spp. (Grizel et al. 1983, Le Borgne & Le Pennec 1983, Bougrier et al. 1986, Pascual et al. 1991 and C. rivularis (Cochennec et al. 1998). M. mackini has been shown to infect C. gigas, C. virginica, O. edulis and O. concaphila (Bower et al. 1997) (present Table 1). Therefore, Bonamia spp. and Mikrocytos spp. cannot be distinguished solely by the hosts which they infect. However, to date the geographic distributions of the 2 Mikrocytos species appear to be distinct, with M. mackini having been reported only in western Canada and M. roughleyi only in eastern Australia.Several studies have included observations of the ultrastructure of Bonamia ostreae (Comps et al. 1980, Pichot et al. 1980, Bréhelin et al. 1982, Grizel et al. 1983, Grizel 1985, Chagot et al. 1992, Montes et al. 1994 and B. exitiosus (Dinamani et al. 1987, Hine 1991, Hine & Wesney 1994a,b, Hine et al. 2001b), but there are none on Bonamia sp. in Ostrea angasi in Australia or Tiostrea chilensis in Chile. A recent study on the ssu rDNA gene sequences of B. ostreae (Carnegie et al. 2000, Cochennec et al. 2000 and Bonamia sp. from New Zealand showed that they are co...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Mikrocytos roughleyi taxonomic affiliation leads to the genus Bonamia (Haplosporidia)

Cochennec-Laureau¹,

Reece²,

Berthe³

et al. 2003

Dis. Aquat. Org.

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“…With the exception of the occasional mention of clear forms (Pichot et al 1979, Grizel 1985, most of the information available in the literature on Bonamia ostreae concerns dense forms (Pichot et al 1979, Brehélin et al 1982, Balouet et al 1983, Grizel 1985, Montes et al 1994 or stages slightly developed from it (Hervio et al 1991. A Bonamia-like parasite that infected Suminoe oysters Crassostrea rivularis in France (Cochennec et al 1998) appeared similar to B. ostreae and occurred as the dense form.…”

Section: Comparison With Bonamia Ostreaementioning

confidence: 99%

“…In spite of ultrastructural studies on B. ostreae , Brehélin et al 1982, Balouet et al 1983, Grizel 1985, Montes et al 1994, it is difficult to identify features that clearly distinguish the 2 species. Some monoclonal antibodies raised against B. ostreae labelled Bonamia sp.…”

Section: Introductionmentioning

confidence: 99%

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

Hine¹,

Cochennec-Laureau²,

Berthe³

2001

Dis. Aquat. Org.

100

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Bonamia sp. is a pathogenic parasite that occurs in the haemocytes of dredge oysters Ostrea chilensis Philippi in New Zealand. Ultrastructurally it resembles other haplosporidians in the possession of haplosporosomes, haplosporogenesis, persistence of mitotic microtubules during interphase and of the nuclear envelope during mitosis, and occurrence of a diplokaryotic or multi-nucleate plasmodial stage. Another stage containing a large vacuole derived from enlargement of 1 or more mitochondria has not previously been described from other haplosporidians. It most closely resembles B. ostreae Pichot et al., 1979, which parasitises and is pathogenic in haemocytes of European flat oysters, O. edulis. However, B. ostreae is smaller and denser, and has fewer lipoid bodies and haplosporosomes. We have nearly completely sequenced the small ribosomal gene of the organism from O. chilensis. Initial comparisons of these sequences with those of other protozoans showed similarities to B. ostreae. Polymorphism within Bonamia sp. was confirmed by restriction fragment length polymorphism analysis. On the basis of ultrastructural and molecular considerations it is proposed that this organism be named Bonamia exitiosus sp. nov. KEY WORDS: Bonamia exitiosus · Ostrea chilensis · Ultrastructure · 18S rDNA · New Zealand Resale or republication not permitted without written consent of the publisherDis Aquat Org 47: [63][64][65][66][67][68][69][70][71][72] 2001 MATERIALS AND METHODS Ultrastructural studies. Infected Ostrea chilensis (n = 237) from Foveaux Strait were opened one at a time, the heart was removed and cut in two, imprints were made with one half, and the other half was fixed for ultrastructural studies. Imprints were stained with Hemacolor™ (Merck) and microscopically examined, and heavily infected oysters were selected for further study. Hearts were fixed in 2.5% glutaraldehyde in 0.22 µm filtered seawater for 1 to 2 h, washed twice in filtered seawater, post-fixed in 1% OsO 4 for 1 h, stained en bloc with 5% uranyl acetate in 0.1 M sodium acetate buffer for 45 min, dehydrated in ascending (50 to 100%) ethyl alcohol, embedded in Araldite, sectioned, stained with 5% uranyl acetate for 10 min and in 5% lead citrate for 5 to 6 min, and examined on a Philips 420ST TEM.To compare Bonamia sp. with B. ostreae, quantitative data were taken from published studies on the ultrastructure of B. ostreae (Pichot et al. 1979, Brehélin et al. 1982, Balouet et al. 1983, Grizel 1985, Hervio et al. 1991 and from archived material held at the IFREMER laboratory at Ronce-les-Bains, La Tremblade, France. Samples were compared directly under the TEM from blocks of B. ostreae infected Ostrea edulis kindly lent by Steve Feist of the MAFF Fish Diseases Laboratory, Weymouth, England.Base sequence studies. DNA extraction: Genomic DNA was extracted from Bonamia sp. infected Ostrea chilensis using the following procedure. Ethanol fixed tissues were suspended in 1 ml of extraction buffer (NaCl 100 mM, EDTA 25 mM, pH 8, SDS 0.5%) with proteina...

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A Possible Life Cycle for Bonamia ostreae on the Basis of Electron Microscopy Studies

Cited by 41 publications

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Mikrocytos roughleyi taxonomic affiliation leads to the genus Bonamia (Haplosporidia)

Mikrocytos roughleyi taxonomic affiliation leads to the genus Bonamia (Haplosporidia)

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

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