Evaluation of metal pollution-induced biological effects in Chinese shrimp Fenneropenaeus chinensis by NMR-based metabolomics

Ambient copper modulates immunocompetence and induces physiological responses in Penaeus monodon against white spot syndrome virus infection

Among trace metals, copper is essential for crustaceans' normal growth and metabolism. In the present study, an attempt was made to determine whether the addition of copper in rearing water influences the physiological and immunological responses of Penaeus monodon to white spot syndrome virus infection (WSSV). Adult P. monodon were distributed in experimental tanks and exposed to 0, 0.05, 0.1, 0.2 and 0.3 mg l-1 copper concentrations. After 14 days, the shrimps were challenged with WSSV and the biochemical/immune variables were determined on post-metal exposure day 14 and post-challenge days 2 and 5. Significant variations could be observed in the haemolymph (biochemical and immune) variables of P. monodon on exposure to copper and WSSV challenge. Shrimps exposed to copper at 0.1 mg l-1 showed higher total haemocyte count, phenol oxidase activity, nitro blue tetrazolium salt reduction, alkaline/acid phosphatase activity, total protein, carbohydrates, lipids, glucose and cholesterol besides maximum post-challenge survival. However, exposure to copper at 0.2 and 0.3 mgl-1 increased the susceptibility to WSSV infection, showing a decrease in the biochemical/immune variables. Therefore, the present study concludes that copper in ambient water induces immunomodulation and evokes physiological responses in P. monodon at sub-lethal doses. Immunostimulatory effects elicited by copper at 0.1 mg l-1 enhanced the immunocompetence and reduced the susceptibility of P. monodon to WSSV infection, conferring protection to the animals and resulting in higher survival.

NMR technique revealed the metabolic interference mechanism of the combined exposure to cadmium and tributyltin in grass carp larvae

Widespread human activity has resulted in the presence of different pollutants in the aquatic environment that does not exist in isolation. The study of the effects of contamination of aquatic organisms is of great significance. To assess the individual and combined toxicity of cadmium (Cd) and tributyltin (TBT) to aquatic organisms, juvenile grass carp (Ctenopharyngodon idella) were exposed to Cd (2.97 mg/L), TBT (7.5 μg/L), and their mixture MIX. The biological response was evaluated by nuclear magnetic resonance (NMR) analysis of plasma metabolites. Plasma samples at 1, 2, 4, 8, 16, 32, and 48 days post-exposure were analyzed using detection by NMR technique. The typical correlation analysis (CCA) analysis revealed that TBT had the greatest effect on plasma metabolism, followed by MIX and Cd. The interference pathway to grass carp was similar to that of TBT and MIX. Both Cd and TBT exposure alone or in combination can lead to metabolic abnormalities in TCA cycle-related pathways and interfere with energy metabolism. These results provide more detailed information for the metabolic study of pollutants and data for assessing the health risks of Cd, TBT, and MIX at the metabolic level.

Effect of High Hydrostatic Pressure on the Metabolite Profile of Striped Prawn (Melicertus kerathurus) during Chilled Storage

A variety of metabolites contribute to the freshness and taste characteristics of seafood. This study investigated the effects of high hydrostatic pressure (HHP; 400, 500, and 600 MPa) for 10 min) on the metabolome of striped prawn during chilled storage, in relation to microorganisms' development. All treated samples showed lower viable counts throughout storage compared to the untreated counterparts. The limit of acceptability from a microbiological point of view was extended from 9 to as many as 35 days by 600 MPa treatment. Metabolites were quantified by ¹H-NMR through a targeted-untargeted metabolomic approach. Molecules linked to nucleotides' degradation and amines' anabolism suggested an overall freshness improvement granted by HHP. Notably, putrescine and cadaverine were detected only in untreated prawn samples, suggesting the inactivation of degradative enzymes by HHP. The concentration of molecules that influence umami perception was significantly elevated by HHP, while in untreated samples, the concentration of molecules contributing to a sour taste gradually increased during storage. As metabolomics was applied in its untargeted form, it allowed us to follow the overall set of metabolites related to HHP processing and storage, thus providing novel insights into the freshness and taste quality of striped prawn as affected by high hydrostatic pressure.

Metabolomic Alterations in the Digestive System of the Mantis Shrimp Oratosquilla oratoria Following Short-Term Exposure to Cadmium

Mantis shrimp Oratosquilla oratoria is an economically critical aquatic species along the coast of China but strongly accumulates marine pollutant cadmium (Cd) in its digestive system. It is necessary to characterize the toxicity of Cd in the digestive system of mantis shrimp. The metabolic process is an essential target of Cd toxicity response. In this work, we used ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-TOF-MS) for untargeted metabolomics to characterize the metabolic changes in the digestive system of O. oratoria, exposed to 0.05 mg/L for 96 h. The aim of this study was to further investigate the effect of O. oratoria on Cd response to toxicity and develop biomarkers. Metabolomics analysis showed the alteration of metabolism in the digestive system of mantis shrimp under Cd stress. A total of 91 metabolites were differentially expressed and their main functions were classified into amino acids, phospholipids, and fatty acid esters. The enrichment results of differential metabolite functional pathways showed that biological processes such as amino acid metabolism, transmembrane transport, energy metabolism, and signal transduction are significantly affected. Based on the above results, the Cd-induced oxidative stress and energy metabolism disorders were characterized by the differential expression of amino acids and ADP in mantis shrimp, while the interference of transmembrane transport and signal transduction was due to the differential expression of phospholipids. Overall, this work initially discussed the toxicological response of Cd stress to O. oratoria from the metabolic level and provided new insights into the mechanism.

UPLC/MS-based untargeted metabolomics reveals the changes in muscle metabolism of electron beam irradiated Solenocera melantho during refrigerated storage

Shrimp meat is an extremely perishable product; however, refrigeration can slow down spoilage. In this study, we used electron beam irradiation (EBI) to pre-treat shrimp meat and analyzed the metabolites of the treated shrimp meat during refrigerated storage using metabonomic analysis methods. In total, 4865 metabolites were identified, of which, 103 differential metabolites had KEGG (Kyoto Encyclopedia of Genes and Genomes) IDs. Further, two potential biomarkers were obtained. Based on the results, l-lysine was downregulated, while 2'-deoxyguanosine 5'-monophosphate and dihydroxyacetone phosphate acyl ester were upregulated during the refrigerated storage. The metabolic activity began to weaken gradually after 9 days. However, the different metabolites related to EBI were not identified herein. Nonetheless, the study findings revealed the metabolic changes in Solenocera melantho at the molecular level during refrigerated storage after EBI.

Ecological and toxicological assessments of anthropogenic contaminants based on environmental metabolomics

There has long been a great concern with growing anthropogenic contaminants and their ecological and toxicological effects on living organisms and the surrounding environment for decades. Metabolomics, a functional readout of cellular activity, can capture organismal responses to various contaminant-related stressors, acquiring direct signatures to illustrate the environmental behaviours of anthropogenic contaminants better. This review entails the application of metabolomics to profile metabolic responses of environmental organisms, e.g. animals (rodents, fish, crustacean and earthworms) and microorganisms (bacteria, yeast and microalgae) to different anthropogenic contaminants, including heavy metals, nanomaterials, pesticides, pharmaceutical and personal products, persistent organic pollutants, and assesses their ecotoxicological impacts with regard to literature published in the recent five years. Contaminant-induced metabolism alteration and up/down-regulation of metabolic pathways are revealed in typical organisms. The obtained insights of variations in global metabolism provide a distinct understanding of how anthropogenic contaminants exert influences on specific metabolic pathways on living organisms. Thus with a novel ecotechnique of environmental metabolomics, risk assessments of anthropogenic contaminants are profoundly demonstrated.

Metal pollution and its biological effects in swimming crab Portunus trituberculatus by NMR-based metabolomics

Metal pollution in the Bohai Sea in China has posed a potential risk on marine organisms. In this work, crabs (Portunus trituberculatus) were sampled from four sites, namely a reference (site 3934) and three metal-polluted (sites 6151, 6351, and 3562) sites, located in the Bohai Sea. Metal concentrations in crab gill tissues were measured using inductively coupled plasma mass spectrometry. Cu, Zn, and Cd in crab samples from S3562 presented the highest concentrations. Particularly, Cu concentration exceeded the marine biological quality standard II. Cd contents in crab samples from all metal-polluted sites exceeded the marine biological quality standard I. Nuclear magnetic resonance-based metabolomics indicated metal pollution-induced immune stresses in crab samples from all metal-polluted sites. Metal pollution in S6151 and S6351 disturbed energy metabolism through differential pathways. For crab samples from S3562, the metabolic profile suggested that metal pollution mainly induced osmotic stress.