A description of karyotype of the giant liver fluke Fascioloides magna (Trematoda, Platyhelminthes) and a review of Fasciolidae cytogenetics

Abstract

69 SummaryThe study describes a karyotype of a common parasite of cervids, the giant liver fluke, Fascioloides magna (Trematoda, Platyhelminthes). The chromosome set of F. magna comprises 11 pairs of chromosomes, all classified as subtelocentric except for the submeta-metacentric pair No. 8 and the submetacentric pair No. 10 (2n = 22, n = 1sm + 1sm-m + 9st). The first longest pair is 4.65 μm long and the length decreases continuously to the 1.92 μm length of the last pair No. 11. No distinct secondary constriction has been observed in mitotic preparations. Fluorescent DAPIstaining reveals distinct heterochromatin bands on all 11 chromosome pairs in the centromeric regions; another DAPI-positive bands are localized at the end of the long arms of chromosomes No. 5 and the last less distinct signals appear interstitially on the long arms of the pair No. 6. Synchronous meiotic divisions of 8-spermatocyte groups have been observed during spermatogenesis, similarly with a development of spermatocytes in other trematodes. In the first two stages of heterotypic spermatocyte division, 11 bivalents (n = 11) are regularly observed, confirming the diploid number of 22 elements. Furthermore, the present analysis summarises and discusses available cytogenetic data on Fasciolidae flukes suitable for future studies on taxonomy or phylogenetic interrelationships within the family.

Morphological characterization of adult Fascioloides magna (Trematoda: Fasciolidae): first SEM report

“…In sheep, wide tunnels are made through the liver parenchyma, and infection with only two or three flukes can result in fatal injury (Soulsby 1986). Apart from the epidemiological, genetic, and molecular findings that have already been demonstrated by other researchers (Ursprung et al 2006;Novobilsky et al 2007;Kralova-Hromadova et al 2008;Bazsalovicsova et al 2010;Reblanova et al 2010;Radvansky et al 2011), there is a paucity of information on F. magna using scanning electron microscopy (SEM) (Coil 1977(Coil , 1981Fried et al 1986;Qureshi et al 1989). The present study reports the findings of SEM evaluation of adult F. magna removed from naturally infected calves.…”

A comparative study of karyotypes and chromosomal location of rDNA genes in important liver flukes Fasciola hepatica and Fascioloides magna (Trematoda: Fasciolidae)

“…The absolute length found by Romanenko and Pleshanova (1975) was much lower than this reported later (Špakulová and Králová 1991;present results). These differences were caused very probably by various methodology used, as discussed for instance by Reblánová et al (2010). In all European populations of F. hepatica, the first chromosome pair was two-armed (submeta-or metacentric) and markedly longer than the subsequent pair no.…”

“…Interrelationships among fasciolid species based on evolutionary history have recently been analyzed by extensive works which discussed also hypotheses about probable origin of the fasciolids and historic routs of their dispersion (Lotfy et al 2008;Mas-Coma et al 2009). The papers account a complex of molecular, morphological, and life cycle data; however, chromosomal features were not comprised in spite of the fact that several data on fasciolid karyotypes already exist (for review, see Reblánová et al 2010). Cytogenetic analyses, chiefly those providing information on chromosomal location of various genes, may improve re-appraisals of phylogenetic interrelationships within target organisms.…”

“…Concerning cytogenetics of F. hepatica, number of chromosomes were studied many times and the haploid set n=10 was first detected already by Sanderson (1953). Diploid (2n), triploid (3n) or mixoploid (2n/3n) specimens were detected in F. hepatica and some congeners originating from many Asian countries, some Pacific islands, and also Britain and Ireland (Fletcher et al 2004;Peng et al 2009;Ichikawa and Itagaki 2010;Reblánová et al 2010 and references therein). The chromosome morphology was described only three times.…”

“…Nowadays, the parasite occurs in more or less extensive areas of Central Europe with tendency to invade new areas down the River Danube (for review, see Špakulová et al 2003). The karyotype of F. magna was described only recently by Reblánová et al (2010). It comprises 11 pairs of chromosomes present in a diploid set, all classified as subtelocentric except for the submeta-metacentric pair no.…”