Mitochondrial genome of Hypoderaeum conoideum – comparison with selected trematodes

Abstract

BackgroundHypoderaeum conoideum is a neglected but important trematode. The life cycle of this parasite is complex: snails serve as the first intermediate hosts: bivalves, fishes or tadpoles serve as the second intermediate hosts, and poultry (such as chickens and ducks) act as definitive hosts. In recent years, H. conoideum has caused significant economic losses to the poultry industry in some Asian countries. Despite its importance, little is known about the molecular ecology and population genetics of this parasite. Knowledge of mitochondrial (mt) genome of H. conoideum can provide a foundation for phylogenetic studies as well as epidemiological investigations.MethodsThe entire mt genome of H. conoideum was amplified in five overlapping fragments by PCR and sequenced, annotated and compared with mt genomes of selected trematodes. A phylogenetic analysis of concatenated mt amino acid sequence data for H. conoideum, eight other digeneans (Clonorchis sinensis, Fasciola gigantica, F. hepatica, Opisthorchis felineus, Schistosoma haematobium, S. japonicum, S. mekongi and S. spindale) and one tapeworm (Taenia solium; outgroup) was conducted to assess their relationships.ResultsThe complete mt genome of H. conoideum is 14,180 bp in length, and contains 12 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and one non-coding region (NCR). The gene arrangement is the same as in Fasciola spp, with all genes being transcribed in the same direction. The phylogenetic analysis showed that H. conoideum had a relatively close relationship with F. hepatica and other members of the Fasciolidae, followed by the Opisthorchiidae, and then the Schistosomatidae.ConclusionsThe mt genome of H. conoideum should be useful as a resource for comparative mt genomic studies of trematodes and for DNA markers for systematic, population genetic and epidemiological studies of H. conoideum and congeners.

Characterization and comparative analysis of the complete mitochondrial genome of Azygia hwangtsiyui Tsin, 1933 (Digenea), the first for a member of the family Azygiidae

“…The mt genome of A. hwangtsiyui has 22 intergenic spacers ranging from 1 to 15 bp and contains two overlapping nucleotides ranging from 1 to 40 bp (Table 1). Noteworthily, a 40 bp overlap between the nad4 and nad4L genes exists in the A. hwangtsiyui mitogenome, which is consistent with most helminths such as Eurytrema pancreaticum Janson, 1889 (Chang et al 2016), Hypoderaeum conoideum (Bloch, 1782) (Yang et al 2015), but shorter than that of Schistosoma mekongi Voge, Bruckner & Bruce, 1978 (64 bp;Littlewood et al 2006). The nucleotide contents of T, C, A, G, in A. hwangtsiyui mitogenome are 42.8%, 12.0%, 16.8%, and 28.5%, respectively ( Table 2).…”

Molecular phylogenetics and mitogenomics of three avian dicrocoeliids (Digenea: Dicrocoeliidae) and comparison with mammalian dicrocoeliids

“…This modification of anticodons, supposedly a homoplasy [50], from GCT to TCT (in trnS1) and CTT to TTT (in trnK) was also found in some other flatworms, e.g. Hypoderaeum conoideum (Trematoda: Echinostomatidae) [52] and Khawia sinensis (Cestoda: Caryophyllidea) [53]. The secondary structures of tRNAs were similar to those in the corresponding genes in E. pancreaticum [20]; all tRNAs except for trnS1 (AGN) and trnS2 (UCN), could be folded into the typical cloverleaf secondary structure.…”

The complete mitochondrial genome of Orthocoelium streptocoelium (Digenea: Paramphistomidae) for comparison with other digeneans

“…Amino acid sequences translated from individual genes of the mt genome of O. streptocoelium were concatenated and aligned with those of other digeneans, including C. sinensis (NC_012147) (Shekhovtsov et al, 2010), Dicrocoelium chinensis (NC_025279.1) (Liu et al, 2014a), Fasciola gigantica (NC_024025) (Liu et al, 2014b), F. hepatica (NC_002546) (Le et al, 2001), Fischoederius elongatus (KM_397348) (Yang et al, 2015a), Haplorchis taichui (NC_022433.1) (Lee et al, 2013), Metagonimus yokogawai (KC330755.1), Hypoderaeum conoideum (KM_111525) (Yang et al, 2015b), Opisthorchis viverrini (JF739555.1) (Anderson, 1998), P. cervi (NC_023095.1) (Yan et al, 2013), Paragonimus westermani (AF219379.2), Schistosoma haematobium (NC_008074) (Littlewood et al, 2006), Schistosoma japonicum (AF215860) (Le et al, 2001), Schistosoma mekongi (NC_002529) (Le et al, 2000), Schistosoma spindale (NC_008067) (Littlewood et al, 2006), and the cestode Taenia solium (outgroup) (NC_004022.1) (Nakao et al, 2003). The phylogenetic analysis of O. streptocoelium and other digeneans was conducted using the neighbour-joining method employing the Tamura–Nei model in MEGA 5 (Tamura et al, 2011).…”