Intraspecific variability in several isolates of Philasterides dicentrarchi (syn. Miamiensis avidus), a scuticociliate parasite of farmed turbot

Turbot resistance to Philasterides dicentrarchi is more dependent on humoral than on cellular immune responses

“…Isolation and culture of P. dicentrarchi P. dicentrarchi specimens, isolates I 1 and C 1 , were obtained aseptically from ascitic fluid of turbot suffering an outbreak of scuticociliatosis that occurred on two local fish farms (Galicia, Spain) [1,11,12]. The isolates were cultured at 18 C in L-15 Leibovitz medium, supplemented with 10% inactivated foetal bovine serum (FBS), lipids (lecithin and Tween 80), nucleosides, glucose and an antibiotic antimycotic solution (100 units/ml of penicillin G, 0.1 mg of streptomycin sulphate and 0.25 mg/ml of amphotericin B) (complete L-15), as previously described [20].…”

“…It has been suggested, on the basis of morphological and virulence studies, that there may exist different strains of scuticociliates that are pathogenic for turbot [10] and it has been found that vaccination with different P. dicentrarchi isolates does not always confer cross-protection [11]. Characterisation of seven P. dicentrarchi isolates obtained from outbreaks of turbot scuticociliatosis in different parts of the Iberian Peninsula showed intraspecific variation at morphological and genetic levels [12].…”

Taxonomy and morphology of four "ophrys-related" scuticociliates (Protista, Ciliophora, Scuticociliata), with the description of a new genus, Paramesanophrys gen. nov.

“…Noticeably, they share many common morphological characteristics, e.g., body usually elongate, oval or cylindrical with a pointed anterior end but no apical plate; cytostome positioned at, or anterior to, the mid-body; buccal apparatus comprising a paroral membrane (PM) and three Parauronema-like membranelles, membranelle 1 (M1) and membranelle 2 (M2) each composed of two or more rows of kinetids. Most species are opportunistic parasites (Noland 1937;Borror 1963;Grolière & Léglise 1977;Strüder & Wilbert 1992;Song & Wilbert 2000;Song et al , 2003Song et al , 2009Budiño et al 2011). Among these genera, Metanophrys and Mesanophrys are the most closely related (body slender, with apical plate absent, cytostome in the anterior half of the body and three Parauronema-like membranelles), with their main difference being the position of the PM relative to M2 (PM extending anteriorly to the middle portion of M2 in Metanophrys vs. to the posterior end of M2 in Mesanophrys) (Small & Lynn 1985;Strüder & Wilbert 1992;Song & Wilbert 2000).…”

Differences in the in vitro susceptibility to resveratrol and other chemical compounds among several Philasterides dicentrarchi isolates from turbot

“…At present, the most effective way of preventing P. dicentrachi infection in turbot is by vaccination (Sitjà-Bobadilla et al 2008;Sanmartín et al 2008;Lamas et al 2008). However, a high degree of intraspecific genetic variation was found among several isolates of P. dicentrarchi obtained from turbot fish farms in Spain and Portugal, after morphological and genetic characterization of the isolates (Alvarez-Pellitero et al 2004;Budiño et al 2011). This is important because vaccination experiments with different serotypes of this scuticociliate did not find any cross protection between the serotypes (Piazzon et al 2008;Song et al 2009).…”

“…Specimens of seven isolates of P. dicentrarchi were collected under aseptic conditions from ascitic fluid of infected turbot, Psetta maxima (L.), cultured in fish farms in Galicia (northwest Spain) and Portugal (Budiño et al 2011). The ciliates were then cultured in complete sterile L-15 medium as previously described (Iglesias et al 2003).…”