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Aldeadávila de la Ribera, Spain

Maccari M.,University of Hull | Maccari M.,Institute Acuicultura Of Torre Of La Sal | Amat F.,Institute Acuicultura Of Torre Of La Sal | Gomez A.,University of Hull
PLoS ONE | Year: 2013

There is wide interest in understanding how genetic diversity is generated and maintained in parthenogenetic lineages, as it will help clarify the debate of the evolution and maintenance of sexual reproduction. There are three mechanisms that can be responsible for the generation of genetic diversity of parthenogenetic lineages: contagious parthenogenesis, repeated hybridization and microorganism infections (e.g. Wolbachia). Brine shrimps of the genus Artemia (Crustacea, Branchiopoda, Anostraca) are a good model system to investigate evolutionary transitions between reproductive systems as they include sexual species and lineages of obligate parthenogenetic populations of different ploidy level, which often co-occur. Diploid parthenogenetic lineages produce occasional fully functional rare males, interspecific hybridization is known to occur, but the mechanisms of origin of asexual lineages are not completely understood. Here we sequenced and analysed fragments of one mitochondrial and two nuclear genes from an extensive set of populations of diploid parthenogenetic Artemia and sexual species from Central and East Asia to investigate the evolutionary origin of diploid parthenogenetic Artemia, and geographic origin of the parental taxa. Our results indicate that there are at least two, possibly three independent and recent maternal origins of parthenogenetic lineages, related to A. urmiana and Artemia sp. from Kazakhstan, but that the nuclear genes are very closely related in all the sexual species and parthenogegetic lineages except for A. sinica , who presumable took no part on the origin of diploid parthenogenetic strains. Our data cannot rule out either hybridization between any of the very closely related Asiatic sexual species or rare events of contagious parthenogenesis via rare males as the contributing mechanisms to the generation of genetic diversity in diploid parthenogenetic Artemia lineages. © 2013 Maccari et al.

Redondo M.J.,Institute Acuicultura Of Torre Of La Sal | Alvarez-Pellitero P.,Institute Acuicultura Of Torre Of La Sal
Parasitology International | Year: 2010

The influence of Enteromyxum spp. infections on the carbohydrate patterns of the digestive tract of gilthead sea bream (GSB) Sparus aurata L. and turbot (TB) Psetta maxima (L.) has been studied. Histochemical stainings to differentiate the types of mucins and lectin-binding assays to detect terminal carbohydrate residues were applied to histological sections of GSB and TB uninfected or infected by Enteromyxum leei and E. scophthalmi, respectively. The number of intestinal GC decreased in severely infected fish in both parasitoses, though changes in mucin patterns were limited to the decrease in the staining intensity for acidic mucins in infected GSB. The TB stomach and intestine lacked histochemically detectable acidic mucins, or sialic acid detectable by SNA, in contrast with their abundance in GSB. Glucose/mannose, fucose and GlcNAc residues were less abundant in both infected hosts with respect to uninfected fish. In contrast, D-Gal and D-GalNAc moieties (detectable by BSL I) increased in most parts of E. scophthalmi-infected TB while decreasing (oesophagus) or remaining unchanged (intestine) in E. leei-infected GSB. The decreasing in the expression of acidic mucins and of sialic acid detectable by SNA in E. leei-infected GSB is remarkable. Differences in the carbohydrate patterns between both hosts could aid to explain the differences in the severity of both enteromyxoses. In addition, the changes induced by Enteromyxum spp. infections in the digestive tract of GSB and TB suggest a role of terminal carbohydrate residues in the parasite-host interaction. © 2010 Elsevier Ireland Ltd.

Guillot R.,Institute Acuicultura Of Torre Of La Sal | Ceinos R.M.,CSIC - Institute of Marine Research | Cal R.,Spanish Institute of Oceanography | Rotllant J.,CSIC - Institute of Marine Research | Cerda-Reverter J.M.,Institute Acuicultura Of Torre Of La Sal
PLoS ONE | Year: 2012

While flatfish in the wild exhibit a pronounced countershading of the dorso-ventral pigment pattern, malpigmentation is commonly observed in reared animals. In fish, the dorso-ventral pigment polarity is achieved because a melanization inhibition factor (MIF) inhibits melanoblast differentiation and encourages iridophore proliferation in the ventrum. A previous work of our group suggested that asip1 is the uncharacterized MIF concerned. In order to further support this hypothesis, we have characterized asip1 mRNAs in both turbot and sole and used deduced peptide alignments to analyze the evolutionary history of the agouti-family of peptides. The putative asip precursors have the characteristics of a secreted protein, displaying a putative hydrophobic signal. Processing of the potential signal peptide produces mature proteins that include an N-terminal region, a basic central domain with a high proportion of lysine residues as well as a proline-rich region that immediately precedes the C-terminal poly-cysteine domain. The expression of asip1 mRNA in the ventral area was significantly higher than in the dorsal region. Similarly, the expression of asip1 within the unpigmented patches in the dorsal skin of pseudoalbino fish was higher than in the pigmented dorsal regions but similar to those levels observed in the ventral skin. In addition, the injection/electroporation of asip1 capped mRNA in both species induced long term dorsal skin paling, suggesting the inhibition of the melanogenic pathways. The data suggest that fish asip1 is involved in the dorsal-ventral pigment patterning in adult fish, where it induces the regulatory asymmetry involved in precursor differentiation into mature chromatophore. Adult dorsal pseudoalbinism seems to be the consequence of the expression of normal developmental pathways in an inaccurate position that results in unbalanced asip1 production levels. This, in turn, generates a ventral-like differentiation environment in dorsal regions. © 2012 Guillot et al.

Servili A.,Institute Federatif Of Recherche 140 | Le Page Y.,Institute Federatif Of Recherche 140 | Leprince J.,University of Rouen | Caraty A.,French National Institute for Agricultural Research | And 5 more authors.
Endocrinology | Year: 2011

Kisspeptins are new actors in the neuroendocrine regulation of reproduction. In vertebrates, the number of kiss genes varies from none to three. Zebrafish have two kiss genes, kiss1 and kiss2, and two kiss receptors (GPR54), kiss1r and kiss2r. To provide detailed information on the organization of the kiss systems in zebrafish, antibodies were raised against the C terminus of zebrafish preproKiss1 and preproKiss2. Immunohistochemistry fully confirmed in situ hybridization data, showing that kiss1-expressing neurons are only located in the habenular nucleus, while kiss2-expressing neurons are found in the dorsal and ventral hypothalamus. Kiss1-expressing cells project only to the interpeduncular and raphe nuclei and strongly expressed the kiss1r receptor. In contrast, kiss2-expressing cells are mostly present in the dorsal and ventral hypothalamus and project widely into the subpallium, the preoptic area, the thalamus, the ventral and caudal hypothalamus, and the mesencephalon. All these regions strongly expressed the kiss2r messengers. Kiss2 fibers profusely innervate the ventral forebrain and notably made close apposition with GnRH3 neurons. Estrogen treatment of juvenile fish with estradiol causes increase in kiss2 and kiss2r expression. In the pituitary gland, no proKiss2-positive fibers were detected, while positive cells were observed in the pars intermedia. In addition to proposing a successful strategy to develop antibodies to kisspeptins, these data indicate that the kiss2 systems of zebrafish are implicated in reproductive events, while the kiss1 gene would play other functions that remain to be established. Copyright © 2011 by The Endocrine Society.

Redondo M.J.,Institute Acuicultura Of Torre Of La Sal | Alvarez-Pellitero P.,Institute Acuicultura Of Torre Of La Sal
Experimental Parasitology | Year: 2010

The involvement of the lectin/carbohydrate interaction in the invasion of the turbot intestinal epithelium by Enteromyxum scophthalmi was studied in vitro using explants of turbot intestine and pre-treatment of parasite stages with the plant lectins of Canavalia ensiformis (Con A) and Glycine max (SBA). Both lectins inhibited the attachment and invasion of E. scophthalmi stages to the intestinal epithelium, though the inhibitory effect was higher for SBA than for Con A. Such results point to the involvement of N-acetyl-galactosamine (GalNAc) and galactose (Gal) residues and also of mannose/glucose residues in the E. scophthalmi-intestinal epithelium interaction. The inhibitory effect of both lectins on the parasite adhesion and penetration points to the interest of further studies to confirm the presence of putative lectins recognising GalNAc-Gal and mannose/glucose residues in turbot intestine. The obtained results demonstrated also the adequacy of turbot intestinal explants as an in vitro model to study the interaction with E. scophthalmi. © Elsevier Inc.

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