Preliminary results on the uptake and biochemical response to water-exposure of Tamiflu® (oseltamivir phosphate) in two marine bivalves

Fast and efficient extract oseltamivir from aquatic products using magnetic covalent organic frameworks/graphene oxide composite prior to liquid chromatography-tandem mass spectrometry analysis

In this work, a magnetic covalent organic framework/graphene oxide composite (MCOF/GO) was rapidly synthesized and developed as a promising candidate for the magnetic solid-phase extraction (MSPE). Combined with HPLC-MS, an efficient and rapid analytical method was established for the determination of oseltamivir (OS) in aquatic products. The resultant composite not only exhibited superior extraction efficiency, but also possessed fast mass transfer kinetic, reducing the pretreatment time greatly. Under optimal conditions, the linear range of the proposed method for OS determination was found to be 0.1-10 μg/kg along with a satisfactory correlation coefficient (R² = 0.997) and a low limit of detection (LOD, 0.035 μg/kg). Furthermore, the established method was utilized to determine OS in Carp, Yellow croaker, and Shrimp, where the recoveries ranged from 87% to 116%. These results demonstrate the splendid application potential of this method to detect antiviral drugs in actual aquatic products.

Biomarker responses and metabolism in Lumbricus terrestris exposed to drugs of environmental concern, an in vivo and in vitro approach

The earthworm Lumbricus terrestris is an anecic species living in natural soils but it is also a sentinel in pollution monitoring. Specimens of L.terrestris were exposed for 48 h though the filter paper contact test at 1 mg/mL of the chemicals: Lamotrigine (LMG), Cocaine (COC), Fipronil (FIP) and the pesticide bis-4-nitrophenyl phosphate (BNPP). After that period, the activities of Acetylcholinesterase, Glutathione S-transferase, Carboxylesterase (CE) using different substrates, and lipid peroxidation levels were evaluated in the exposed whole tissue earthworms. The results revealed differences only in CE activity, with 4-nitrophenyl butyrate (4NPB) and 1-naphthyl butyrate (1NB) the most responsive substrates to COC. The kinetic parameters of CE were characterized, for the first time, in whole tissue of this species. The chemical analysis by LC-MS/MS, confirmed the exposure to the parent compounds, identified metabolites and evidenced biotransformation pathways in earthworms. Metabolic reactions included oxidation (LMG and FIP), hydrolysis (COC and FIP) as well as glycosylation (LMG, COC and FIP). A hitherto unknown metabolite of LMG due to the conjugation with phenylalanine glutamine was formed. The in vivo results on CE activity with the specific inhibitor, BNPP, were confirmed in vitro. Moreover, in the in vitro approach, the inclusion of other contaminants of environmental concern supports the potential of CE as biomarker. This study identifies the main metabolites formed by earthworms for further in vivo exposures under more realistic conditions and the potential use of CE measures as biomarker of emerging contaminants.

The use of an in vitro approach to assess marine invertebrate carboxylesterase responses to chemicals of environmental concern

Carboxylesterases (CEs) are key enzymes which catalyse the hydrolysis reactions of multiple xenobiotics and endogenous ester moieties. Given their growing interest in the context of marine pollution and biomonitoring, this study focused on the in vitro sensitivity of marine invertebrate CEs to some pesticides, pharmaceuticals, personal care products and plastic additives to assess their potential interaction on this enzymatic system and its suitability as biomarkers. Three bivalves, one gastropod and two crustaceans were used and CEs were quantified following current protocols set for mammalian models. Four substrates were screened for CEs determination and to test their adequacy in the hepatic fraction measures of the selected invertebrates. Two commercial recombinant human isoforms (hCE1 and hCE2) were also included for methodological validation. Among the invertebrates, mussels were revealed as the most sensitive to xenobiotic exposures while gastropods were the least as well as with particular substrate-specific preferences. Among chemicals of environmental concern, the plastic additive tetrabromobisphenol A displayed the highest CE-inhibitory capacity in all species. Since plastic additives easily breakdown from the polymer and may accumulate and metabolise in marine biota, their interaction with the CE key metabolic/detoxification processes may have consequences in invertebrate's physiology, affect bioaccumulation and therefore trophic web transfer and, ultimately, human health as shellfish consumers.

Multi-organ characterisation of B-esterases in the European sea bass (Dicentrarchus labrax): Effects of the insecticide fipronil at two temperatures

In fish, the study of cholinesterases (ChEs) and carboxylesterases (CEs), apart from their involvement in neural activity and xenobiotic metabolism, respectively, requires to be further explored. The European sea bass (Dicentrarchus labrax) was the fish model used to characterise B-esterases in several matrices and organs, as well as to assess the impacts of the insecticide fipronil at two temperatures: the natural temperature at the time of sampling (13 °C) and at 16 °C (based on climate change-related predictions for the Mediterranean region). Fipronil exerts harmful effects in non-target species; however, some countries are reluctant to implement regulations without additional evidence on their toxicity. A comprehensive study was performed in fish pre-acclimated to the two targeted temperatures for 15 days. B-esterases were evaluated in multiple samples after 7 and 14 day exposures to fipronil in feed (dose of 10 mg/kg) and after a 7-day depurative period. Based on hydrolysis rates, results showed that CEs were measurable in all matrices while ChEs were more abundant in muscle and, particularly, acetylcholinesterase (AChE) in the brain. A + 3 °C increase in temperature had little influence on B-esterase activity; however, fipronil caused a significant increase in brain AChE (1.5-fold) and CE (3-fold) activities. Other matrices and organs also experienced alterations in their B-esterase activities that could compromise their physiological functions.

Effects of pollution on marine organisms

This review covers selected 2019 articles on the biological effects of pollutants, including human physical disturbances, on marine and estuarine plants, animals, ecosystems, and habitats. The review, based largely on journal articles, covers field, and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing, and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, marine debris, dredging, and disposal. Special emphasis is placed on effects of oil spills and marine debris due largely to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico and proliferation of data on the assimilation and effects of marine debris microparticulates. Several topical areas reviewed in the past (e.g., mass mortalities ocean acidification) were dropped this year. The focus of this review is on effects, not on pollutant sources, chemistry, fate, or transport. There is considerable overlap across subject areas (e.g., some bioaccumulation data may be appeared in other topical categories such as effects of wastewater discharges, or biomarker studies appearing in oil toxicity literature). Therefore, we strongly urge readers to use keyword searching of the text and references to locate related but distributed information. Although nearly 400 papers are cited, these now represent a fraction of the literature on these subjects. Use this review mainly as a starting point. And please consult the original papers before citing them.

Biochemical and physiological responses of two clam species to Triclosan combined with climate change scenario

Ocean acidification and warming are among the man-induced factors that most likely impact aquatic wildlife worldwide. Besides effects caused by temperature rise and lowered pH conditions, chemicals of current use can also adversely affect aquatic organisms. Both climate change and emerging pollutants, including toxic impacts in marine invertebrates, have been investigated in recent years. However, less information is available on the combined effects of these physical and chemical stressors that, in nature, occur simultaneously. Thus, this study contrasts the effects caused by the antimicrobial agent and plastic additive, Triclosan (TCS) in the related clams Ruditapes philippinarum (invasive) and Ruditapes decussatus (native) and evaluates if the impacts are influenced by combined temperature and pH modifications. Organisms were acclimated for 30 days at two conditions (control: 17 °C; pH 8.1 and climate change scenario: 21 °C, pH 7.7) in the absence of the drug (experimental period I) followed by a 7 days exposure under the same water physical parameters but either in absence (unexposed) or presence of TCS at 1 μg/L (experimental period II). Biochemical responses covering metabolic, oxidative defences and damage-related biomarkers were contrasted in clams at the end of experimental period II. The overall picture showed a well-marked antioxidant activation and higher TCS bioaccumulation of the drug under the forecasted climate scenario despite a reduction on respiration rate and unaltered metabolism in the exposed clams. Since clams are highly consumed shellfish, the consequences for higher tissue bioaccumulation of anthropogenic chemicals to final consumers should be alerted not only at present conditions but more significantly under predicted climatic conditions for humans but also for other components of the marine trophic chain.

Impact of long-term parental exposure to Tamiflu metabolites on the development medaka offspring (Oryzias latipes)

Despite the widespread use of the antiviral drug, Tamiflu®, little is known about the long-term toxic effects of drug or its metabolites in an aquatic ecosystem. This study integrated epidemiological and ecotoxicological methods to determine environmentally relevant concentrations of Tamiflu. A model based on the species medaka (Oryzias latipes) was then used to determine the health status and reproductivity of adults exposed to the drug as well as the embryonic development of offspring. The proposed ecotoxicological model was also used to quantitatively and qualitatively evaluate the toxicodynamic parameters related to egg production, hatchability, and development. Our results revealed that at an environmentally relevant exposure, Tamiflu and its metabolites had no adverse effects on growth, survival, or fecundity of adult medaka. Nonetheless, we observed a reduction in hatchability under exposure to 300 μg L^-1 and a reduction in body length under exposure exceeding 90 μg L^-1. Under exposure to 300 μg L^-1, the estimated spawning time to reach 50% of the maximum percentage of cumulative egg production (ET50) far exceeded that of the control group (without exposure to Tamiflu). We also observed a ∼ 3-fold decrease in maximum egg hatching (E_max). Based on an integrated epidemiological and ecotoxicological model, predictions of environmental concentrations of Tamiflu and its metabolites revealed that the influenza subtypes associated with increases in environmental concentrations: A(H3N2) > A(H1N1) > type B (in order of their effects). We also determined that A(H3N2) posed a potential risk to hatchability and development. Note however, the environmental concentrations of Tamiflu and its metabolites in most countries are lower than the effect concentrations derived in this study, indicating no hazards for aquatic environments. We recommend the use of hatchability and embryonic development as indicators in assessing the effects of long-term parental exposure to Tamiflu metabolites.

Comprehensive study of sulfamethoxazole effects in marine mussels: Bioconcentration, enzymatic activities and metabolomics

Antibiotics accumulation in aquatic organisms may be of great concern from an ecological point of view but also from a human perspective, especially when they are accumulated in edible animals like marine mussels. In this work, mussels (Mytilus galloprovincialis) were exposed to sulfamethoxazole antibiotic (SMX) at 10 µg/L during 96 h, followed by 24 h of depuration. The experiment was carried out at summer and winter conditions. SMX showed a bioconcentration factor in mussel of 1.5 L/kg (dry weight) and 69% of the compound was eliminated from the organism in 24 h. The metabolomics approach revealed alterations in amino acids levels (aspartate, phenylalanine, valine and tryptophan) pinpointing disturbances in osmotic regulation and energy metabolism. Besides, the levels of some nucleotides (guanosine and inosine) and a carboxylic acid were also affected. However, SMX exposed mussels did not show any significant alteration in the enzymatic activities related to the xenobiotic metabolism and oxidative stress. Moreover, some of the changes observed in mussel's metabolites suggested alterations in mussel's organoleptic characteristics that can affect its quality as seafood commodity. Overall, our results showed that SMX exposure to marine mussels may have ecological implications by provoking sub-lethal effects to exposed organisms. Nevertheless, no risk for consumers derived from mussel ingestion is expected due to the low bioconcentration capacity of SMX and fast depuration in this seafood type.