The use of host specificity, pathogenicity, and molecular markers to differentiate between <i>Gyrodactylus salaris</i> Malmberg, 1957 and <i>G. thymalli</i> Zitnan, 1960 (Monogenea: Gyrodactylidae)

Sterud, Erik; Mo, Tor Atle; Collins, Catherine; Cunningham, Carey O.

doi:10.1017/s0031182001001044

Cited by 43 publications

(64 citation statements)

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“…At present, the internal transcribed spacers (ITS1 and ITS2) of nuclear ribosomal RNA genes are the most common molecular marker used to discriminate these parasites (Cunningham 1997;Matìjusová et al 2001Matìjusová et al , 2003Ziêtara et al 2000;Ziêtara and Lumme 2004). The intergenic spacer (IGS) of ribosomal RNA genes have also been tested for G. salaris and G. thymalli , Sterud et al 2002, Hansen et al 2006. The subunit 1 of the mitochondrial cytochrome oxidase (COI) gene may also be used successfully to differentiate species and local Gyrodactylus strains (Meinilä et al 2002(Meinilä et al , 2004Hansen et al 2003Hansen et al , 2007.…”

Section: Introductionmentioning

confidence: 99%

Identification of Gyrodactylus ectoparasites in Polish salmonid farms by PCR-RFLP of the nuclear ITS segment of ribosomal DNA (Monogenea, Gyrodactylidae)

Rokicka

Lumme

Ziętara

2007

Acta Parasitologica

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The Gyrodactylus fauna of 274 fish taken from ten salmonid farms in Poland was sampled in 2006. Four fish species were investigated: rainbow trout Oncorhynchus mykiss, brown trout Salmo trutta (morphs fario, lacustris, and trutta), grayling Thymallus thymallus and huchen Hucho hucho. No parasites were observed on huchen. No indications of gyrodactylosis were observed, but an unexpected parasite species diversity was found. A molecular species identification by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) of ITS1 + 5.8S + ITS2 was utilized, with addition of morphometric methods. The most frequent parasite was a new record in Poland, G. teuchis. It was present in two molecular forms on brown trout and rainbow trout, which also carried G. derjavinoides and G. truttae. Three molecular forms of G. salaris/G. thymalli were found, the standard type ITS only on grayling. A heterozygous (or heterogenic) G. salaris type described earlier in Denmark was found in seven farms on rainbow trout, and a complementary homozygous clone which differs from the standard by three nucleotides, in two farms. This homozygous form has not been recorded earlier. The PCR-RFLP results were confirmed by sequencing ITS segment from representative specimens of each type and comparing them with all available salmonid-specific Gyrodactylus sequences in GenBank. The Polish fauna with seven different Gyrodactylus clones separated by PCR-RFLP was the most diverse reported in fish farms in any country so far.

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Section: Introductionmentioning

confidence: 99%

Identification of Gyrodactylus ectoparasites in Polish salmonid farms by PCR-RFLP of the nuclear ITS segment of ribosomal DNA (Monogenea, Gyrodactylidae)

Rokicka

Lumme

Ziętara

2007

Acta Parasitologica

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“…Sterud et al (2002) found small but consistent differences between G. salaris and G. thymalli in the nucleotide sequences of the intergenic spacer (IGS) of the ribosomal DNA cassette. Surprisingly high levels of intra-and interspecific differentiation of the mitochondrial cytochrome oxidase I gene (CO1) in populations of G. salaris and G. thymalli populations have recently been detected (Hansen et al 2003, Meinilä et al 2004).…”

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confidence: 96%

“…Morphometric discrimination of G. salaris and G. thymalli is possible using sophisticated statistics (McHugh et al 2000), but this study was based on a limited number of G. thymalli specimens, and on G. salaris specimens that were pooled from several populations across Scandinavia. However, these species have been shown to have different host preferences (Soleng and Bakke 2001, Bakke et al 2002, Sterud et al 2002.…”

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confidence: 99%

The use of morphometric characters to discriminate specimens of laboratory-reared and wild populations of Gyrodactylus salaris and G. thymalli (Monogenea)

Shinn

Hansen²,

Olstad³

et al. 2004

FOLIA PARASIT

106

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Abstract. Gyrodactylus thymalli Žitňan, 1960 and G. salaris Malmberg, 1957 have an indistinguishable ribosomal internal transcribed spacer (ITS) DNA sequence, but exhibit surprisingly high levels of intra-and interspecific sequence variation of the mitochondrial cytochrome oxidase I (CO1) gene. To test whether different populations of these reportedly very similar species could be discriminated using morphometric methods, we examined the morphometry of four different populations representing different mitochondrial clades. Twenty five point-to-point measurements, including five new characters of the attachment hooks, were recorded from three Norwegian laboratory populations (G. salaris from the Rivers Lierelva and Rauma, and G. thymalli from the River Rena), and from one wild population of G. thymalli from the River Test, UK. The Norwegian populations were kept under identical environmental conditions to control for the influence of temperature on the haptoral attachment hooks. Data were subsequently subjected to univariate and linear stepwise discriminant analyses. The model generated by the linear stepwise discriminant analysis used 18 of the 25 original variables, the first two roots accounting for 96.6% of the total variation between specimens. The hamulus shaft length accounts for 66.7% of the overall correct classification efficiency. Based on morphometry, all specimens were assigned to the correct species. Apart from three specimens of G. salaris from the River Lierelva population which were misclassified as belonging to the G. salaris Rauma population, all specimens were assigned to the correct population. Thus, populations of Gyrodactylus identified by mtDNA can also be discriminated using morphometric landmark distances.

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“…This similarity supports the morphological (Žitňan 1960, Ergens 1983, Malmberg 1993, Mo 1994, Denham and Long 1999 and genetic (Cunningham et al 1995b, Zietara and Lumme 2002) similarities reported. However, G. thymalli has a restricted reproduction on salmon (Soleng and Bakke 2001, Bakke et al 2002, Sterud et al 2002), and Shinn et al (2000, using morphology, were able to differentiate G. thymalli from G. salaris, as was Sterud et al (2002) by sequencing the intergenic spacer region (IGS). Of the five populations under study, only the chaetotaxy pattern of G. caledoniensis could be discriminated from the others, but only based on the position of a single sensillum in two different clusters on the dorsal surface.…”

Section: Discussionmentioning

confidence: 99%

“…Each clade was found to be unique in having a different invasion history and pathogenesis to salmon (Bakke et al 2002, Sterud et al 2002. Hence, there is an urgent need to find morphological markers which can readily separate specimens into their respective species and clades.…”

Section: Species Of the Monogenean Genus Gyrodactylusmentioning

confidence: 99%

Chaetotaxy applied to Norwegian Gyrodactylus salaris Malmberg, 1957 (Monogenea) clades and related species from salmonids

Nilsen¹,

Shinn²

2004

FOLIA PARASIT

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Abstract. Gyrodactylus salaris Malmberg, 1957 is a major pathogen of wild Salmo salar L. parr populations in Norway, and its delimitation from non-pathogenic species is important. The present study was undertaken to test the power of chaetotaxy to differentiate between three populations belonging to both the same and different clades (as stated by mtDNA) of G. salaris, in addition to three different species of gyrodactylids (G. salaris, G. thymalli and G. caledoniensis). The gyrodactylids were processed for chaetotaxy in situ and a maximum of 50 specimens per collection site were used to construct a generalised map over the sensilla. The sensilla were found in all populations to be symmetrically distributed around the median longitudinal axis, according to a formula of 7 dorsal (34 sensilla) and 8 ventral (44 sensilla) clusters on each side of the median line. The three Norwegian populations of G. salaris were found identical, as were the population of G. thymalli. The specimens of G. caledoniensis from Scotland, however, were found to differ from the Norwegian species G. salaris and G. thymalli by the position of one sensillum in two of the clusters. A comparison of the sensillum pattern of laboratory maintained G. salaris (River Lierelva) with results obtained ten years earlier, questions the temporal stability of the chaetotaxy pattern. The present results indicate that chaetotaxy can be used to discriminate between certain Gyrodactylus spp. but not generally.

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The use of host specificity, pathogenicity, and molecular markers to differentiate between Gyrodactylus salaris Malmberg, 1957 and G. thymalli Zitnan, 1960 (Monogenea: Gyrodactylidae)

Cited by 43 publications

References 0 publications

Identification of Gyrodactylus ectoparasites in Polish salmonid farms by PCR-RFLP of the nuclear ITS segment of ribosomal DNA (Monogenea, Gyrodactylidae)

Identification of Gyrodactylus ectoparasites in Polish salmonid farms by PCR-RFLP of the nuclear ITS segment of ribosomal DNA (Monogenea, Gyrodactylidae)

The use of morphometric characters to discriminate specimens of laboratory-reared and wild populations of Gyrodactylus salaris and G. thymalli (Monogenea)

Chaetotaxy applied to Norwegian Gyrodactylus salaris Malmberg, 1957 (Monogenea) clades and related species from salmonids

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