Sequence comparisons of toxic and non-toxic Alexandrium tamarense (Dinophyceae) isolates from UK waters

Higman, Wendy; Stone, David M.; Lewis, Jane

doi:10.2216/i0031-8884-40-3-256.1

Cited by 61 publications

(60 citation statements)

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“…Ribosomal DNA sequence variation has previously been used to discriminate between toxic and non-toxic strains of Alexandrium tamarense and Pseudonitzschia spp. (Scholin et al 1994, Higman et al 2001) and the geographic origin and identity of virulent Perkinsus marinus strains (Robledo et al 1999, Reece et al 2001. A PCR-based restriction fragment length polymorphism assay (PCR-RFLP) based on the ITS1 region has been used to differentiate between Hematodinium infections in Callinectes sapidus, Liocarcinus depurator and Portunus trituberculatus (Small et al 2007) suggesting that this region can be used to identify different Hematodinium species.…”

Section: Discussionmentioning

confidence: 99%

Conservation in the first internal transcribed spacer region (ITS1) in Hematodinium species infecting crustacean hosts found in the UK and Newfoundland

Small

Shields²,

Moss³

et al. 2007

Dis. Aquat. Org.

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Parasitic dinoflagellates in the genus Hematodinium infect a number of decapod crustaceans in waters off the UK, including the Norway lobster Nephrops norvegicus and the edible crab Cancer pagurus. This study investigated sequence variability in the first internal transcribed spacer (ITS1) region of the ribosomal RNA complex of Hematodinium spp. infecting N. norvegicus, C. pagurus, and Pagurus bernhardus from 4 locations in the UK and from the Hematodinium sp. infecting Chionoecetes opilio from the province of Newfoundland and Labrador, Canada. Phylogenetic analysis of the Hematodinium ITS1 sequences from N. norvegicus, C. pagurus, P. bernhardus and C. opilio suggest that these crustaceans are infected with the same species of Hematodinium. Length variability of the ITS1 region was observed (324 to 345 bp) and attributed to 4 variable microsatellite regions (CATG) n , (GCC) n TCCGC(TG) n , (TA) n , and (GAA) n (GGA) n within the sequenced ITS1 fragment. The observed variation may be due to co-infection of the host crustacean with several different strains of Hematodinium or differences among copies of ITS1 region within the genome of a single parasite cell. The Hematodinium ITS1 sequence from N. norvegicus, C. pagurus, P. bernhardus and C. opilio isolates was sufficiently conserved in primer binding regions targeted by previous molecular diagnostic assays; therefore, we suggest that this assay could be used to screen for Hematodinium infections in these crustacean hosts. KEY WORDS: Hematodinium · Conservation of ITS1 · Crustacean hosts · Parasite Resale or republication not permitted without written consent of the publisherDis Aquat Org 75: [251][252][253][254][255][256][257][258] 2007 In waters surrounding the UK Hematodinium-like infections have been reported in Nephrops norvegicus from the Clyde and Irish seas (Field et al. 1992, Briggs & McAliskey 2002 and in Cancer pagurus from the English Channel (Stentiford et al. 2002) and from the Atlantic Ocean (Anonymous 2004). Both N. norvegicus and C. pagurus support large and valuable fisheries in UK waters; however, it is unknown whether different species of Hematodinium parasites infect each of these different hosts or whether one species infects multiple hosts.PCR-based diagnostics to detect Hematodinium spp. have been developed for detecting infections in several host species (Hudson & Adlard 1994, Gruebl et al. 2002, Small et al. 2006, 2007. In the first 2 studies the primer binding regions were in the 18S and 5.8S ribosomal RNA genes and are almost certainly genus specific, not species specific, due to the conserved nature of these genes. Small et al. (2006) developed a potentially species-specific set of PCR primers to target the Hematodinium sp. infecting Nephrops norvegicus using the conserved 18S rRNA gene and variable first internal transcribed spacer region (ITS) of the rRNA gene complex. This PCR assay also detected infections in Cancer pagurus from the English Channel tentatively suggesting that this is either the same species or a closel...

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Section: Discussionmentioning

confidence: 99%

Conservation in the first internal transcribed spacer region (ITS1) in Hematodinium species infecting crustacean hosts found in the UK and Newfoundland

Small

Shields²,

Moss³

et al. 2007

Dis. Aquat. Org.

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“…Examples of spontaneous and complete loss of toxicity by dinoflagellate cultures are rare and in all previous cases, the non-toxic strain has, on detailed examination, been determined to be a different species or a regional genotype that is uniformly non-toxic (e.g. United Kingdom ribotypes of Alexandrium tamarense (Higman et al 2001). However, one credible example reports the complete loss of toxicity by a culture of A. minutum (= A. lusitanicum) during or after its transfer to another laboratory (Martins et al 2004).…”

Section: Bacterial Community Influence On Dinoflagellate Cell Toxicitymentioning

confidence: 99%

Bacterial diversity of Gymnodinium catenatum and its relationship to dinoflagellate toxicity

Green

Hart

Blackburn

et al. 2010

Aquat. Microb. Ecol.

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Gymnodinium catenatum Graham (Dinophyceae) is one of several marine dinoflagellates responsible for outbreaks of paralytic shellfish poisoning (PSP), a problem that is considered to be increasing globally. Bacteria associated with these dinoflagellates have been implicated as potentially involved with the production of PSP toxins, and this study sought to identify whether there was a link between the toxicity of G. catenatum laboratory cultures and the diversity of the associated bacterial community. Bacterial 16S rRNA gene clone libraries were constructed and sequenced to identify the bacterial diversity of 7 G. catenatum cultures of 2 contrasting toxicity levels. Phylogenetic membership and community structure were examined, including the use of UniFrac, F ST and LIB-COMPARE. No statistically significant differences that distinguished between toxic and low-toxicity G. catenatum cultures were identified in the bacterial community membership or structure. Furthermore, no coherent phylogenetic group of bacteria was observed to co-associate with culture toxicity. However, observed variation in bacterial diversity and community structure was based on the geographic origin of the G. catenatum cultures. Overall, while it was not possible to identify an apparent link between bacterial diversity and the toxicity of G. catenatum cultures, we suggest, on the balance of this study and others, that bacterial influence on PSP toxin production may be indirect and mediated by the effects of the bacterial community on algal physiology. KEY WORDS: Gymnodinium catenatum · Paralytic shellfish toxins · 16S rDNA bacterial diversity · Algae-associated bacteria Resale or republication not permitted without written consent of the publisher

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“…Indeed, both toxic and nontoxic strains have been reported for species producing both paralytic shellfish poisoning (PSP) and ASP toxins (e.g. Bates et al 1998, Higman et al 2001, and strainspecific differences in the production of aldehydes has been also recorded (Pohnert et al 2002). A few isolates of Pseudo-nitzschia delicatissima from the Gulf of Naples tested for domoic acid production were found to be non-toxic (Orsini et al 2002).…”

Section: Ecological Implicationsmentioning

confidence: 99%

Toxic Pseudo-nitzschia multistriata (Bacillariophyceae) from the Gulf of Naples: morphology, toxin analysis and phylogenetic relationships with other Pseudo-nitzschia species

et al. 2002

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The genus Pseudo-nitzschia includes a number of species responsible for blooms in coastal and open waters worldwide. P. delicatissima, a species reported as a potential source of amnesic shellfish poisoning (ASP), reaches high concentrations in the Gulf of Naples (Mediterranean Sea), where it regularly blooms in spring and, at times, in autumn. We assessed both intra-and interindividual genetic diversity of this species before and during a bloom (February to April 2001) by sequencing the internal transcribed spacer regions (ITS1 and ITS2) and the 5.8S gene of the nuclear ribosomal DNA. PCR products obtained from 70 strains were cloned and several ITS copies were sequenced for each strain to assess intra-individual polymorphism. Phylogenies showed the presence of 5 distinct, well-supported lineages within what was considered to be a single morphospecies. Genetic diversity was higher in pre-bloom conditions, while all strains collected at the height of the bloom clustered within a single major clade. Ultrastructural investigations carried out on selected strains revealed morphological features slightly different from the ones typical for P. delicatissima only in 1 strain, outside the major clade. Our results, supported by the analysis of the hypervariable domains of LSU (large subunit) rDNA carried out on selected strains, suggest the presence of cryptic diversity within P. delicatissima. Such diversity could in fact explain the existence of toxic and nontoxic strains within the same species and the occasional mismatches between 'species-specific' molecular probes and target species. KEY WORDS: Diatoms · Pseudo-nitzschia delicatissima · ITS nDNA · Cryptic diversity · BloomResale or republication not permitted without written consent of the publisher

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Sequence comparisons of toxic and non-toxic Alexandrium tamarense (Dinophyceae) isolates from UK waters

Cited by 61 publications

References 0 publications

Conservation in the first internal transcribed spacer region (ITS1) in Hematodinium species infecting crustacean hosts found in the UK and Newfoundland

Conservation in the first internal transcribed spacer region (ITS1) in Hematodinium species infecting crustacean hosts found in the UK and Newfoundland

Bacterial diversity of Gymnodinium catenatum and its relationship to dinoflagellate toxicity

Toxic Pseudo-nitzschia multistriata (Bacillariophyceae) from the Gulf of Naples: morphology, toxin analysis and phylogenetic relationships with other Pseudo-nitzschia species

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