Screening for protein adducts of naphthalene and chrysene in plasma of exposed Atlantic cod (Gadus morhua)

Integrated lipidomics and transcriptomics analysis reveal lipid metabolism disturbance in scallop (Chlamys farreri) exposure to benzo[a]pyrene

Benzo[a]pyrene (B[a]P) commonly bioaccumulates in lipid-rich tissues due to its lipophilicity and further affects lipid metabolism. The present study systematically investigated the lipid metabolism disturbance in digestive glands of scallops (Chlamys farreri) exposure to B[a]P, based on lipidomics, transcriptomics, molecular and biochemical analysis. We exposed the scallops to environmentally relevant concentrations of B[a]P for 21 days. The bioaccumulation of B[a]P, lipid content and lipid peroxidation in digestive glands were measured. Integrated lipidomics and transcriptomics analysis, the differential lipid species were identified and key genes based on the pathways in which genes and lipid species involved together were selected in scallop exposure to 10 μg/L B[a]P. The changes of lipid profile showed that triglycerides (TGs) were accumulated after 21 days exposure, while the phospholipids (PLs) decreased demonstrated membrane structures were disrupted by B[a]P. In combination with the change of gene expression, we speculated that B[a]P could induce lipids accumulation by up-regulating lipid synthesis-related genes expression, down-regulating lipolysis-related genes expression and interfering with lipid transport. Overall, this study provides new insights into the mechanisms of lipid metabolism disturbance in bivalves exposed to PAHs, and establishes a foundation for understanding the bioaccumulation mechanism of B[a]P in aquatic organisms, which is of great importance for further ecotoxicological study.

Covalent Protein Modification: An Unignorable Factor for Bisphenol A-Induced Hepatotoxicity

Covalent modification of proteins by reactive pollutants/metabolites might trigger various toxicities resulting from the disruption of protein structures and/or functions, which is critical for understanding the mechanism of pollutants-induced toxicity. However, this mechanism has rarely been touched on due to the lack of a methodology. In this research, the protein modification of bisphenol A (BPA) in rats was characterized using a series of liquid chromatography-tandem mass spectrometry (LC-MS) approaches. BPA-modified cysteine (Cys1) was first released from proteins via enzymatic hydrolysis and identified using LC-MS. Moreover, the positive correlation between Cys1 and hepatotoxicity indicated the involvement of protein modification in BPA toxicity. Then, in vitro incubation of BPA with amino acids and protein confirmed that BPA could specifically modify cysteine residues of proteins after bioactivation and provided four additional modification patterns. Finally, 24 BPA-modified proteins were identified from the liver of BPA-exposed rats using proteomic analysis, and they were mainly enriched in oxidative stress-related pathways. The modification on superoxide dismutases, catalase, and glutathione S-transferases disrupted their enzymatic functions, leading to oxidative damage. These results revealed that the covalent protein modification is an unignorable factor for BPA hepatotoxicity. Moreover, the workflow can be applied to identify protein adducts of other emerging contaminants and possible risk.

Proteomics for understanding pathogenesis, immune modulation and host pathogen interactions in aquaculture

Proteomic analyses techniques are considered strong tools for identifying and quantifying the protein contents in different organisms, organs and secretions. In fish biotechnology, the proteomic analyses have been used for wide range of applications such as identification of immune related proteins during infections and stresses. The proteomic approach has a significant role in understanding pathogen surviving strategies, host defence responses and subsequently, the fish pathogen interactions. Proteomic analyses were employed to highlight the virulence related proteins secreted by the pathogens to invade the fish host's defence barriers and to monitor the kinetics of protein contents of different fish organs in response to infections. The immune related proteins of fish and the virulence related proteins of pathogens are up or down regulated according to their functions in defence or pathogenesis. Therefore, the proteomic analyses are useful in understanding the virulence mechanisms of microorganisms and the fish pathogen interactions thereby supporting the development of new effective therapies. In this review, we focus and summarise the recent proteomic profiling studies exploring pathogen virulence activities and fish immune responses to stressors and infections.

The crystal structure of haemoglobin from Atlantic cod

The isolation of the dominant isoform of haemoglobin from Atlantic cod caught in southwest Norway is reported and its X-ray crystal structure is presented.

The crystal structure of haemoglobin from Atlantic cod has been solved to 2.54 Å resolution. The structure consists of two tetramers in the crystallographic asymmetric unit. The structure of haemoglobin obtained from one individual cod suggests polymorphism in the tetrameric assembly.

Applicability of in vitro methods in evaluating the biotransformation of polycyclic aromatic hydrocarbons (PAHs) in fish: Advances and challenges

The biotransformation of polycyclic aromatic hydrocarbons (PAHs) and the biochemical mechanisms involved in such process continue to be intensively studied in the fields of environmental science and toxicology. The investigation of PAH biotransformation in fish is fundamental to understand how piscine species cope with PAH exposure, as these compounds are ubiquitous in aquatic ecosystems and impact different levels of biological organization. New approaches are continuously developed in the field of ecotoxicology, allowing live animal testing to be combined with and, in some cases, replaced with novel in vitro systems. Many in vitro techniques have been developed and effectively applied in the investigation of the biochemical pathways driving the biotransformation of PAH in fish. In vitro experimentation has been fundamental in the advancement of not only understanding PAH-mediated toxicity, but also in highlighting suitable cell-based models for such investigations. Therefore, the present review highlights the value and applicability of in vitro systems for PAH biotransformation studies, and provides up-to-date information on the use of in vitro fish models in the evaluation of PAH biotransformation, common biomarkers, and challenges encountered when developing and applying such systems.