Pomphorhynchus laevis (Acanthocephala) from the Sava River basin: New insights into strain formation, mtDNA-like sequences and dynamics of infection.
Here we report the genetic variability and presence of mtDNA-like sequences of Pomphorhynchus laevis from the chub, Squalius cephalus, caught at the sampling sites along the Sava River and its tributary the Sutla River in Croatia. Sequences of the cytochrome c oxidase subunit 1 (COI) gene of the recovered P. laevis specimens were used for haplotype network construction and phylogenetic analysis. These analyses showed that some specimens contained mitochondrial-like sequences, and they uncovered the existence of a Sava River basin strain different from known strains of P. laevis. This is the first time that P. laevis has been shown to contain mtDNA-like sequences, suggesting the need to exercise caution during COI analyses of P. laevis using universal primers. Highly conserved sequences of two nuclear markers, the ITS region and 18S rRNA, were not helpful for understanding genetic variability or differentiating strains. Furthermore, analysis of the dynamics of P. laevis infections in S. cephalus from the Sava and Sutla Rivers showed decreased prevalence and abundance at sites with inferior water quality, positive association of parasite abundance with fish size, and no clear association of parasite abundance with fish condition index or sex.
Laboratory for Aquaculture and Pathology of Aquatic Organisms, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička c. 54, 10000 Zagreb, Croatia. Electronic address: ivardic@irb.hr.
Irena
I
Vardić Smrzlić
Laboratory for Aquaculture and Pathology of Aquatic Organisms, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička c. 54, 10000 Zagreb, Croatia.
Damir
D
Valić
Laboratory for Aquaculture and Pathology of Aquatic Organisms, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička c. 54, 10000 Zagreb, Croatia.
Damir
D
Kapetanović
Laboratory for Biological Effects of Metals, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička c. 54, 10000 Zagreb, Croatia.
Vlatka
V
Filipović Marijić
Department for Biology and Pathology of Fish and Bees, Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, 10000 Zagreb, Croatia.
Emil
E
Gjurčević
Laboratory for Aquaculture and Pathology of Aquatic Organisms, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička c. 54, 10000 Zagreb, Croatia.
Emin
E
Teskeredžić
D000049:Acanthocephala / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D000818:Animals; D001483:Base Sequence; D017523:Croatia / Q000453:epidemiology; D003530:Cyprinidae / Q000469:parasitology*; D018509:DNA, Helminth / Q000737:chemistry / Q000235:genetics; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics; D005260:Female; D005393:Fish Diseases / Q000453:epidemiology / Q000469:parasitology*; D014644:Genetic Variation; D006239:Haplotypes; D006373:Helminthiasis / Q000453:epidemiology / Q000469:parasitology*; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D045483:Rivers; D017422:Sequence Analysis, DNA / Q000662:veterinary
D018509:DNA, Helminth; D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV
Acanthocephalans; Genetic variability; Mitochondrial-like sequences; Pomphorhynchus laevis; Squalius cephalus; Sutla/Sava Rivers