Dietary methylmercury and fatty acids affect the lipid metabolism of adipose tissue and liver in rainbow trout.

Methylmercury (MeHg) is a pervasive environmental contaminant in aquatic ecosystems that can reach elevated concentrations in fish of high trophic levels, such as salmonids. The present study aims at investigating the individual and combined impacts of dietary MeHg and fatty acids on lipid metabolism in juvenile rainbow trout (Oncorhynchus mykiss) with a focus on two key organs, adipose tissue and liver. MeHg and fatty acids are both known to act on energy homeostasis although little is known about their interplay on lipid metabolism in fish.

QuoVidi: An open-source web application for the organization of large-scale biological treasure hunts.

Learning biology, and in particular systematics, requires learning a substantial amount of specific vocabulary, both for botanical and zoological studies. While crucial, the precise identification of structures serving as evolutionary traits and systematic criteria is not per se a highly motivating task for students. Teaching this in a traditional teaching setting is quite challenging especially with a large crowd of students to be kept engaged.

Lipolysis and Leptin Production of Elephant Seal Blubber Using Precision-Cut Adipose Tissue Slices.

Adipose tissue plays key roles in energy homeostasis. Understanding its metabolism and regulation is essential to predict the impact of environmental changes on wildlife health, especially in fasting-adapted species. However, experimental work in wild vertebrates can be challenging.

Interplay between dietary lipids and cadmium exposure in rainbow trout liver: Influence on fatty acid metabolism, metal accumulation and stress response.

The present study aimed at investigating interactive effects between dietary lipids and both short- and long-term exposures to a low, environmentally realistic, cadmium (Cd) concentration. Juvenile rainbow trout were fed four isolipidic diets (31.7 g/kg) enriched in either linoleic acid (LA, 18:2n-6), alpha-linolenic acid (ALA, 18:3n-3), eicosapentaenoic acid (EPA, 20:5n-3) or docosahexaenoic acid (DHA, 22:6n-3).

Methylmercury displays pro-adipogenic properties in rainbow trout preadipocytes.

Methylmercury (MeHg) is a ubiquitous contaminant largely found in aquatic environments, especially in species at high trophic level such as salmonids. The aim of this study was to evaluate the effects of MeHg on adipocyte differentiation and lipid metabolism in rainbow trout. Primary cultured preadipocytes were exposed to increasing concentrations of MeHg during six days with or without a hormonal cocktail.

Exploring the interactions between polyunsaturated fatty acids and cadmium in rainbow trout liver cells: a genetic and proteomic study.

Polyunsaturated fatty acids (PUFAs) have key biological roles in fish cells. We recently showed that the phospholipid composition of rainbow trout liver cells (RTL-W1 cell line) modulates their tolerance to an acute cadmium (Cd) challenge. Here, we investigated (i) the extent to which PUFAs and Cd impact fatty acid homeostasis and metabolism in these cells and (ii) possible mechanisms by which specific PUFAs may confer cytoprotection against Cd.

Body lipid composition modulates acute cadmium toxicity in Daphnia magna adults and juveniles.

Long chain polyunsaturated fatty acids (LC-PUFAs) such as eicosapentaenoic acid (EPA, 20:5n-3) affect zooplankton fitness and ability to cope with environmental stressors. However, the impact of LC-PUFAs on zooplankton sensitivity to chemical stressors is unknown. Here, we aimed to document the interaction between EPA and cadmium (Cd), as model chemical stressor, in Daphnia magna.

Transcriptional effects of phospholipid fatty acid profile on rainbow trout liver cells exposed to methylmercury.

Lipids, and their constitutive fatty acids, are key nutrients for fish health as they provide energy, maintain cell structure, are precursors of signalling molecules and act as nuclear receptor ligands. These specific roles may be of crucial importance in a context of exposure to pollutants. We recently showed that the fatty acid profile of rainbow trout liver cell phospholipids modulates sensitivity to an acute methylmercury challenge.

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.

The fatty acid profile of rainbow trout liver cells modulates their tolerance to methylmercury and cadmium.

The polyunsaturated fatty acid (PUFA) composition of fish tissues, which generally reflects that of the diet, affects various cellular properties such as membrane structure and fluidity, energy metabolism and susceptibility to oxidative stress. Since these cellular parameters can play an important role in the cellular response to organic and inorganic pollutants, a variation of the PUFA supply might modify the toxicity induced by such xenobiotics. In this work, we investigated whether the cellular fatty acid profile has an impact on the in vitro cell sensitivity to two environmental pollutants: methylmercury and cadmium.

High hydrostatic pressure influences the in vitro response to xenobiotics in Dicentrarchus labrax liver.

Hydrostatic pressure (HP) increases by about 1 atmosphere (0.1MPa) for each ten-meter depth increase in the water column. This thermodynamical parameter could well influence the response to and effects of xenobiotics in the deep-sea biota, but this possibility remains largely overlooked.

Effects of polychlorobiphenyls, polybromodiphenylethers, organochlorine pesticides and their metabolites on vitamin A status in lactating grey seals.

Polychlorobiphenyls (PCBs), polybromodiphenylethers (PBDEs) and organochlorine pesticides (OCPs), such as dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene (HCB), are considered as endocrine disruptors in laboratory and wild animals. This study investigated whether these compounds and their hydroxylated metabolites (HO-PCBs and HO-PBDEs) may affect the homoeostasis of vitamin A, a dietary hormone, in the blubber and serum of twenty lactating grey seals sampled at early and late lactation on the Isle of May, Scotland. The effect of naturally produced compounds such as the methoxylated (MeO)-PBDEs was also examined.

Precision-cut liver slices to investigate responsiveness of deep-sea fish to contaminants at high pressure.

While deep-sea fish accumulate high levels of persistent organic pollutants (POPs), the toxicity associated with this contamination remains unknown. Indeed, the recurrent collection of moribund individuals precludes experimental studies to investigate POP effects in this fauna. We show that precision-cut liver slices (PCLS), an in vitro tool commonly used in human and rodent toxicology, can overcome such limitation.

Selective transfer of persistent organic pollutants and their metabolites in grey seals during lactation.

Twenty grey seal (Halichoerus grypus) mother-pup pairs from the colony of the Isle of May (Scotland) were sampled at early and late lactation in order to study the transfer of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and their metabolites (HO-PCBs and HO-PBDEs) as well as organochlorine pesticides (OCPs), such as DDT and metabolites (DDXs) and hexachlorobenzene (HCB). The transfer of the naturally produced MeO-PBDEs was also investigated. Generally, concentrations (on a lipid weight basis) of the sum of PCBs, PBDEs and DDXs tended to be higher in all tissues at late lactation (for maternal outer blubber ΣPCBs=3860±2091 ng/g, ΣPBDEs=120±74 ng/g and ΣDDXs=559±207 ng/g; for maternal inner blubber ΣPCBs=4229±3274 ng/g, ΣPBDEs=148±118 ng/g and ΣDDXs=704±353 ng/g; for maternal serum ΣPCBs=1271±796 ng/g, ΣPBDEs=27±16 ng/g and ΣDDXs=242±125 ng/g; for milk ΣPCBs=1190±747 ng/g, ΣPBDEs=55±36 ng/g and ΣDDXs=357±160 ng/g; for pup serum ΣPCBs=1451±901 ng/g, ΣPBDEs=48±31 ng/g and ΣDDXs=395±201 ng/g).

Differential changes of fat-soluble vitamins and pollutants during lactation in northern elephant seal mother-pup pairs.

We investigated the changes of vitamins A and E as well as PCBs and DDTs during lactation in northern elephant seal (Mirounga angustirostris) mother-pup pairs. On average, milk vitamin A concentrations were 6 times higher during late lactation than during early lactation, a pattern that differs dramatically from terrestrial mammals. Vitamin A concentrations also significantly increased in the inner blubber throughout lactation, whereas they remained constant in the outer blubber.

Kinetic studies of peroxiredoxin 6 from Arenicola marina: rapid oxidation by hydrogen peroxide and peroxynitrite but lack of reduction by hydrogen sulfide.

Arenicola marina lives in marine environments where hydrogen peroxide concentrations reach micromolar levels. The annelid also forms reactive species through metabolic pathways. Its antioxidant systems include a cytosolic peroxiredoxin, peroxiredoxin 6 (AmPrx6 or AmPRDX6) that shows high homology to the mammalian 1-Cys peroxiredoxin.

Insights into metazoan evolution from Alvinella pompejana cDNAs.

Background: Alvinella pompejana is a representative of Annelids, a key phylum for evo-devo studies that is still poorly studied at the sequence level. A. pompejana inhabits deep-sea hydrothermal vents and is currently known as one of the most thermotolerant Eukaryotes in marine environments, withstanding the largest known chemical and thermal ranges (from 5 to 105°C).

Precision-Cut Liver Slices of Salmo salar as a tool to investigate the oxidative impact of CYP1A-mediated PCB 126 and 3-methylcholanthrene metabolism.

Fish isolated cell systems have long been used to predict in vivo toxicity of man-made chemicals. In present study, we tested the suitability of Precision-Cut Liver Slices (PCLS) as an alternative to these models that allows the evaluation of a global tissue response to toxicants, to investigate oxidative stress response to cytochrome P450 1A (CYP1A) induction in fish liver. PCLS of Salmo salar were exposed for 21 h to increasing doses of 3-methylcholanthrene (3-MC) and Polychlorobiphenyl 126 (PCB 126).

Chemistry around imidazopyrazine and ibuprofen: discovery of novel fatty acid amide hydrolase (FAAH) inhibitors.

Based on the imidazo-[1,2-a]-pyrazin-3-(7H)-one scaffold, a dual action prodrug has been designed for combining antioxidant and anti-inflammatory activities, possibly unmasked upon oxidation. The construction of the target-molecule requires two building blocks, namely a 2-amino-1,4-pyrazine and a 2-ketoaldehyde. Attempts to synthesize the 2-ketoaldehyde (5a) derived from ibuprofen failed, but led to the corresponding 2-ketoaldoxime (7a) which could not be condensed with the pyrazine synthons.

Response of Alvinella pompejana to variable oxygen stress: a proteomic approach.

Alvinella pompejana is one of the most emblematic species of the animal communities colonizing the deep-sea hydrothermal vents of the East Pacific Rise. This extreme environment is characterized by high temporal variability of its physical-chemical parameters. Among these, the variation in concentration of available oxygen should lead to a specific physiological adaptive response of the animal.

In vitro and in vivo studies of 6,8-(diaryl)imidazo[1,2-a]pyrazin-3(7H)-ones as new antioxidants.

A series of 5-aryl and 3,5-diaryl-2-amino-1,4-pyrazines and the derived imidazopyrazinones has been synthesized to study the chemical oxidative degradation of the bicyclic systems in vitro. Imidazopyrazinones mainly degraded following two independent pathways producing their precursors, namely aminopyrazines, and the corresponding amidopyrazines, respectively. Despite the fact that there is no influence of the substituent of the 3-aryl group on the ratio of the products aminopyrazine/amidopyrazine, diarylimidazopyrazinones and diarylaminopyrazines are good antioxidants in vivo.

Cloning and characterization of Arenicola marina peroxiredoxin 6, an annelid two-cysteine peroxiredoxin highly homologous to mammalian one-cysteine peroxiredoxins.

Peroxiredoxins (PRDXs) are a superfamily of thiol-dependent peroxidases found in all phyla. PRDXs are mechanistically divided into three subfamilies, namely typical 2-Cys, atypical 2-Cys, and 1-Cys PRDXs. To reduce peroxides, the N-terminal peroxidatic Cys of PRDXs is first oxidized into sulfenic acid.

The crystal structure of the C45S mutant of annelid Arenicola marina peroxiredoxin 6 supports its assignment to the mechanistically typical 2-Cys subfamily without any formation of toroid-shaped decamers.

The peroxiredoxins (PRDXs) define a superfamily of thiol-dependent peroxidases able to reduce hydrogen peroxide, alkyl hydroperoxides, and peroxynitrite. Besides their cytoprotective antioxidant function, PRDXs have been implicated in redox signaling and chaperone activity, the latter depending on the formation of decameric high-molecular-weight structures. PRDXs have been mechanistically divided into three major subfamilies, namely typical 2-Cys, atypical 2-Cys, and 1-Cys PRDXs, based on the number and position of cysteines involved in the catalysis.

Arenicola marina extracellular hemoglobin: a new promising blood substitute.

The need to develop a blood substitute is now urgent because of the increasing concern over Europe's BSE outbreak and the worldwide HIV/AIDS epidemic, which have cut blood supplies. Extracellular soluble hemoglobin has long been studied for its possible use as a safe and effective alternative to blood transfusion, but this has met with little success. Clinical trials have revealed undesirable side effects-oxidative damage and vasoconstriction-that hamper the application of cell-free hemoglobin as a blood substitute.

Impacts of antibiotics on in vitro UVA-susceptibility of human skin fibroblasts.

Many studies of UVA-induced cell damage use skin cells obtained during plastic surgery. As the skin is contaminated by micro-organisms, antibiotics need to be added to primary skin cell culture media. This study analysed the impact of the most widely used agents, penicillin, streptomycin, and amphotericin B deoxycholate (amB), on UVA-irradiated human skin fibroblasts.