Genetic relationships among Trichinella pseudospiralis isolates from Australian, Nearctic, and Palearctic regions

Abstract

The study of the genetic polymorphism of pathogens is important for phylogenetic and biogeographic studies and, in the case of foodborne pathogens, to trace the origin of food infection. Since its discovery in 1972, the nonencapsulated species Trichinella pseudospiralis has been detected in mammals and birds, and human infection has occurred, in some cases resulting in death. We studied DNA polymorphism among ten T. pseudospiralis isolates from the Palearctic, Nearctic, and Australian regions, screening the sequences of nine genes [18sRNA, a random amplified polymorphism DNA derived sequence, mitochondrial cytochrome oxidase subunit I (COI), cytochrome P450, cynate lyase, epithelial fusion failure-1, and three unknown genes of Tp3, Tp8, and Tp26]. A high identity of sequence for the nine gene loci was obtained among the seven isolates from the Palearctic region and between the two isolates from the Nearctic region. Genetic identity analysis indicated the distinct polymorphism among the three geographical origins. To easily identify T. pseudospiralis genotypes, a polymerase chain reaction-restriction fragment length polymorphism analysis of COI gene was performed, and the results confirmed the DNA polymorphism within T. pseudospiralis, corresponding to the three regions of origin. We have named the three genotypes as "T. pseudospiralis Palearctic genotype" (code T4P), "Nearctic genotype" (code T4N), and "Australian genotype" (code T4A). To further investigate polymorphism among the nonencapsulated Trichinella species, the sequences of four gene loci (COI, P450, cynate lyase, and SB147D) of T. pseudospiralis, T. papuae, and T. zimbabwensis were analyzed, and the results showed high polymorphism among the three species, strongly supporting their classification as separate species.

Molecular evolution of Trichuris muris isolated from different Muridae hosts in Europe

“…Furthermore, these two genotypes can be easily distinguished among them by a PCR-RFLP analysis of this sequence with the ApalI restriction enzyme. Wu et al (2007) studied the genetic relationships among T. pseudospiralis isolates from Australia, Nearctic, and Palearctic regions. They demonstrated that the Palearctic population (seven isolates from six different hosts from four European and two Asian countries) consisted of a uniform genotype suggesting that there is a frequent gene flow among the isolates.…”

Biochemical and Structural Properties of Cyanases from Arabidopsis thaliana and Oryza sativa

“…Reconstruction of phylogenetic relationships among the known cyanases (Figure 2) provided evidence for a common evolutionary origin for plant cyanases. It is suggested that the conserved cyanases are derived from an ancient gene, which makes it possible to study inter- and intra-specific relationships using cyanase as a phylogenetic marker [28]. The high resolution crystal structure of E. coli cyanase explains the structural and kinetic properties of the enzyme: the active enzyme is a homodecamer composed of five inactive dimmers, and catalytic residues were identified [8].…”

First finding of Trichinella pseudospiralis in two tawny owls (Strix aluco) from Sweden

“…Total genomic DNA was also isolated from T. pseudospiralis (code ISS13), T. spiralis (ISS004) and T. britovi (ISS1088) reference strains, maintained in laboratory mice. In addition, samples of DNA from four geographically related T. pseudospiralis isolates previously used in the study of Wu et al (2007) were kindly provided by Dr. Vilam Šnábel. Of these, three isolates were stated as reference samples characterized by code number and locality, namely ISS1348 (Sweden), ISS1432 (Slovakia), ISS141 (Australia-Tasmania) and one non-reference isolate from Finland.…”

“…After electrophoresis, an approximately 419 bp band, previously characterized by a high variability among T. pseudospiralis isolates (La Rosa et al 2001;Wu et al 2007) was subjected to RFLP analysis (restriction fragment length polymorphism) with restriction endonuclease RsaI Fast digest (Fermentas) according to the manufacturer´s instructions. PCR products for above mentioned isolates were purified using NucleoSpin Gel and PCR Clean-up Kit (Machery-Nagel, Germany).…”