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Cultured gill-derived Neoparamoeba pemaquidensis fails to elicit amoebic gill disease (AGD) in Atlantic salmon Salmo salar

Citation

Morrison, RN and Crosbie, PBB and Cook, MT and Adams, MB and Nowak, BF, Cultured gill-derived Neoparamoeba pemaquidensis fails to elicit amoebic gill disease (AGD) in Atlantic salmon Salmo salar, Diseases of Aquatic Organisms, 66, (2) pp. 135-144. ISSN 0177-5103 (2005) [Refereed Article]

DOI: doi:10.3354/dao066135

Abstract

Amoebic gill disease (AGD) affects the culture of Atlantic salmon Salmo salar in the southeast of Tasmania. The disease is characterised by the presence of epizoic Neoparamoeba spp. in association with hyperplastic gill tissue. Gill-associated amoebae trophozoites were positively selected by plastic adherence for culture in seawater, where they proliferated using heat-killed E. coli as a nutrient source. One isolate of gill-harvested amoebae designated NP251002 was morphologically consistent to N. pemaquidensis under light, fluorescence and transmission electron microscopy. Rabbit anti-N. pemaquidensis antiserum bound to NP251002, and N. pemaquidensis small subunit (SSU) ribosomal DNA (18S rDNA) was detected in NP251002 genomic DNA preparations using PCR. A high degree of similarity in the alignment of the NP251002 18S rDNA PCR amplicon sequence with reference isolates of N. pemaquidensis suggested conspecificity. While short-term culture (72 h) of gill-harvested amoebae does not affect the capacity of amoebae to induce AGD, Atlantic salmon challenged with NP251002 after the trophozoites had been 34 and 98 d in culture exhibited neither gross nor histological evidence of AGD. It is not known if NP251002 were avirulent at the time of isolation, had down-regulated putative virulence factors or virulence was inhibited by the culture conditions. Therefore, the time in culture could be a limiting factor in maintaining virulence using the culture technique described here. © Inter-Research 2005.

Item Details

Item Type:Refereed Article
Research Division:Agricultural and Veterinary Sciences
Research Group:Fisheries Sciences
Research Field:Aquaculture
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - Aquaculture
Objective Field:Fisheries - Aquaculture not elsewhere classified
Author:Morrison, RN (Dr Richard Morrison)
Author:Crosbie, PBB (Dr Philip Crosbie)
Author:Adams, MB (Dr Mark Adams)
Author:Nowak, BF (Professor Barbara Nowak)
ID Code:36004
Year Published:2005
Web of Science® Times Cited:30
Deposited By:TAFI - Aquaculture
Deposited On:2005-08-01
Last Modified:2006-06-07
Downloads:0

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