Molecular adaptation to high pressure in cytochrome P450 1A and aryl hydrocarbon receptor systems of the deep-sea fish Coryphaenoides armatus.

Limited knowledge of the molecular evolution of deep-sea fish proteomes so far suggests that a few widespread residue substitutions in cytosolic proteins binding hydrophilic ligands contribute to resistance to the effects of high hydrostatic pressure (HP). Structure-function studies with additional protein systems, including membrane bound proteins, are essential to provide a more general picture of adaptation in these extremophiles. We explored molecular features of HP adaptation in proteins binding hydrophobic ligands, either in lipid bilayers (cytochrome P450 1A - CYP1A) or in the cytosol (the aryl hydrocarbon receptor - AHR), and their partners P450 oxidoreductase (POR) and AHR nuclear translocator (ARNT), respectively. Cloning studies identified the full-length coding sequence of AHR, CYP1A and POR, and a partial sequence of ARNT from Coryphaenoides armatus, an abyssal gadiform fish thriving down to 5000m depth. Inferred protein sequences were aligned with many non-deep-sea homologs to identify unique amino acid substitutions of possible relevance in HP adaptation. Positionally unique substitutions of various physicochemical properties were found in all four proteins, usually at sites of strong-to-absolute residue conservation. Some were in domains deemed important for protein-protein interaction or ligand binding. In addition, some involved removal or addition of beta-branched residues; local modifications of beta-branched residue patterns could be important to HP adaptation. In silico predictions further suggested that some unique substitutions might substantially modulate the flexibility of the polypeptide segment in which they are found. Repetitive motifs unique to the abyssal fish AHR were predicted to be rich in glycosylation sites, suggesting that post-translational changes could be involved in adaptation as well. Recombinant CYP1A and AHR showed functional properties (spectral characteristics, catalytic activity and ligand binding) that demonstrate proper folding at 1atm, indicating that they could be used as deep-sea fish protein models to further evaluate protein function under pressure

Molecular adaptation to high pressure in cytochrome P450 1A and aryl hydrocarbon receptor systems of the deep-sea fish <i>Coryphaenoides armatus</i>

Limited knowledge of the molecular evolution of deep-sea fish proteomes so far suggests that a few widespread residue substitutions in cytosolic proteins binding hydrophilic ligands contribute to resistance to the effects of high hydrostatic pressure (HP). Structure-function studies with additional protein systems, including membrane bound proteins, are essential to provide a more general picture of adaptation in these extremophiles. We explored molecular features of HP adaptation in proteins binding hydrophobic ligands, either in lipid bilayers (cytochrome P450 1A - CYP1A) or in the cytosol (the aryl hydrocarbon receptor - AHR), and their partners P450 oxidoreductase (POR) and AHR nuclear translocator (ARNT), respectively. Cloning studies identified the full-length coding sequence of AHR, CYP1A and POR, and a partial sequence of ARNT from Coryphaenoides armatus, an abyssal gadiform fish thriving down to 5000 m depth. Inferred protein sequences were aligned with many non-deep-sea homologs to identify unique amino acid substitutions of possible relevance in HP adaptation. Positionally unique substitutions of various physicochemical properties were found in all four proteins, usually at sites of strong-to-absolute residue conservation. Some were in domains deemed important for protein-protein interaction or ligand binding. In addition, some involved removal or addition of beta-branched residues; local modifications of beta-branched residue patterns could be important to HP adaptation. In silico predictions further suggested that some unique substitutions might substantially modulate the flexibility of the polypeptide segment in which they are found. Repetitive motifs unique to the abyssal fish AHR were predicted to be rich in glycosylation sites, suggesting that post-translational changes could be involved in adaptation as well. Recombinant CYP1A and AHR showed functional properties (spectral characteristics, catalytic activity and ligand binding) that demonstrate proper folding at 1 atm, indicating that they could be used as deep-sea fish protein models to further evaluate protein function under pressure. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone"

Reproductive patterns and fecundity of the NW Mediterranean deep-sea fish community

2013 Annual Symposium of the Fisheries Society of the British Isles (FSBI Symposium 2013) Deep Sea Fish Biology, 8-11 July 2013, GlasgowThe description of reproductive strategies and fecundity of fish has an important relevance in the study of their biology and population dynamics. However, our knowledge of the reproductive capacity of deep-sea fish is still very poor. Production of eggs is an energy-demanding process and, thus, a shortfall in food supply may cause a decrease in fecundity and/or egg size. Continental slopes are transitional environments between the shelf and deep basins, with strong gradients in pressure, temperature, food supply and light. Therefore, the study of fecundity and egg size of fish along the continental slope can provide important data to better understand the modulation of reproductive capacity. The fish community of the Catalan margin (northwestern Mediterranean) was sampled between 400 and 2700 m depth. The gonads of 2672 individuals from 13 different species were analyzed macroscopically to determine sex and maturity stage. The mature ovaries of a subsample of 300 individuals were dissected out for histological and image analyses. The oocyte-size distribution patterns show that all species analyzed present group synchronous ovarian organization. Total fecundity and egg size were quantified for the first time for the 13 species considered. The results were compared with previous published data on shallow-water and Atlantic species. Preliminary results showed a pattern of decreased fecundity with depth. Fecundity and egg sizes were lower in Mediterranean species compared to congeneric species in the Atlantic Ocean as reported in the literature. The results are discussed in relation to environmental characteristicsPeer Reviewe

Reproductive strategies of NW Mediterranean deep-sea fish community

40th CIESM Congress: The largest Forum on Mediterranean and Black Sea Research, 28 October - 1 November 2013, Marseille, France.-- 1 page, 1 figureThe reproductive strategies and fecundity of 13 species of the NW Mediterranean deep-sea fish community (750-2250 m depth) were analyzed. The results were compared with previous published data of shallower-living NW Mediterranean species . The results showed that all species analyzed present group-synchronous ovarian organization. All the species present the general pattern of large eggs and low Total Fecundity (TF) in comparison with shallower distributed fish species. TF is positively correlated with fish length. However, no significant relationship between length and depth was found, suggesting that the environmental factors associated with depth play an important role in determining fecundityPeer Reviewe

Bathymetric gradients of fecundity and egg size in fishes: A Mediterranean case study

There is a general hypothesis that species inhabiting deep-sea waters have lower fecundity and larger eggs than shallower species. However, there are few comparative studies which explore this trend because of the complexity of sampling in deep waters, especially in fishes. We present here the first analysis of fecundity and egg size with depth along an isothermal environment. We calculate the relative fecundity and egg size of 11 species of demersal deep-sea fish from the western Mediterranean and included in our analyses published data for an additional 14 species from the same geographic area. The results show that the relative fecundity (eggs per g of individual) of the analyzed fishes slightly decreased along the bathymetric gradient, whereas egg size increased with depth. When the analysis was conducted including only species from the order Gadiformes, the most speciose group in the region and with the widest depth range of distribution (50–2000 m), there was no relationship between relative fecundity and depth, while the deepest species had larger egg sizes than shallower ones. The finding of similar relative fecundities but larger egg sizes suggests that these deep-sea species are investing a higher amount of energy in the production of offspring than shallower water counterparts. The results are discussed in relation to the isothermal characteristics of the deep Mediterranean Sea and ecological adaptations for reproductive successVersión del editor2,42

A global biogeographic classification of the mesopelagic zone

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