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Analytical detection of parasite infection of Dinophysis norvegica using FISH probes
Abstract
Parasites of the genus Amoebophrya infect several freeliving
dinoflagellates, including harmful species. Whereas advanced infection can be easily detected, earlier stages of infection are more difficult to establish. rRNA-based fluorescent in situ hybridisation (FISH) probes specific to Amoebophrya sp. infecting Dinophysis norvegica in the Baltic Sea were combined with 4’,6-diamidino-2-phenylindole (DAPI) staining to study this host-parasite system in a series of samples collected over a 24h period in August 1998. Small forms of Amoebophrya sp. (6–8ìm) within D. norvegica, undetected by DAPI staining, were revealed by the FISH probe. As a result, the average infection estimated by FISH (7.8%) was 6.5 times higher than the estimate based on DAPI alone. Multiple infections were observed
in 75% of the infected D. norvegica cells, indicating that this may be a common feature in this host-parasite system. FISH probes therefore provide a valuable tool to assess parasite infection of dinoflagellates in field
samples.
dinoflagellates, including harmful species. Whereas advanced infection can be easily detected, earlier stages of infection are more difficult to establish. rRNA-based fluorescent in situ hybridisation (FISH) probes specific to Amoebophrya sp. infecting Dinophysis norvegica in the Baltic Sea were combined with 4’,6-diamidino-2-phenylindole (DAPI) staining to study this host-parasite system in a series of samples collected over a 24h period in August 1998. Small forms of Amoebophrya sp. (6–8ìm) within D. norvegica, undetected by DAPI staining, were revealed by the FISH probe. As a result, the average infection estimated by FISH (7.8%) was 6.5 times higher than the estimate based on DAPI alone. Multiple infections were observed
in 75% of the infected D. norvegica cells, indicating that this may be a common feature in this host-parasite system. FISH probes therefore provide a valuable tool to assess parasite infection of dinoflagellates in field
samples.
