Tralopyril bioconcentration and effects on the gill proteome of the Mediterranean mussel Mytilus galloprovincialis

Abstract

Antifouling (AF) systems are used worldwide as one of the most cost-effective ways of protecting submerged structures against heavy biofouling. The emergence of environmentally friendly AF biocides requires knowledge on their environmental fate and toxicity. In this study we measured the bioconcentration of the emerging AF biocide tralopyril (TP) in the Mediterranean mussel Mytilus galloprovincialis and investigated the effects of TP on the mussel gill proteome following acute (2days) and chronic (30days) exposure, as well as after a 10-day depuration period. The experiments were carried out with 1μg/L TP; blank and solvent (5×10(-5)% DMSO) controls were also included. Proteomics analysis was performed by mass spectrometry-based multidimensional protein identification technology (MudPIT). Differentially expressed proteins were identified using a label-free approach based on spectral counts and G-test. Our results show that TP is rapidly accumulated by mussels at concentrations up to 362ng/g dw (whole tissues), reaching steady-state condition within 13days. Ten days of depuration resulted in 80% elimination of accumulated TP from the organism, suggesting that a complete elimination could be reached with longer depuration times. In total, 46 proteins were found to be regulated in the different exposure scenarios. Interestingly, not only TP but also DMSO alone significantly modulated the protein expression in mussel gills following acute and chronic exposure. Both compounds regulated proteins involved in bioenergetics, immune system, active efflux and oxidative stress, often in the opposite way. Alterations of several proteins, notably several cytoskeletal ones, were still observed after the depuration period. These may reflect either the continuing chemical effect due to incomplete elimination or an onset of recovery processes in the mussel gills. Our study shows that exposure of adult mussels to sublethal TP concentration results in the bioconcentration of this biocide in the tissues and modulates the expression of several proteins that may intervene in important metabolic pathways.

Proteome evolution under non-substitutable resource limitation

“…Sample preparation for protein analysis was done following established procedures 42 , 43 . Briefly, frozen algae were thawed at room temperature before lysis, homogenized using a grinder, sonicated on ice (3 × 10 s with 30 s pause in-between) and finally centrifuged (13,000 rpm, 60 min, 4 °C).…”

“…The instrument was operated in positive ion mode (needle voltage: + 1.2 kV, tube lens: 135 V, ion transfer capillary: 200 °C). Using a standard 11-step MudPIT protocol, peptides were sequentially eluted onto the C18 column by eleven salt pulses (4.9 min, from 0 to 100% eluent C, in 10% increments, eluent C: 0.5 M aqueous NH 4 Ac, 5% ACN, 0.1% formic acid), and then separated by gradient elution 42 , 43 .…”

Biofouling in marine aquaculture: a review of recent research and developments

“…While booster biocides are often marketed as environmentally friendly alternatives to conventional copper coatings, there are still environmental concerns regarding their toxicity. Copper pyrithione, for example, reduced salmonid gill health in laboratory assays (Borg and Trombetta 2010) and impacted nontarget organisms (Bao et al 2011;Oliveira et al 2014;Oliveira et al 2016;Amara et al 2018).…”

Toxicity of emerging antifouling biocides to non-target freshwater organisms from three trophic levels

“…Therefore, since DMSO was used in all solutions to dissolve the biocides, treatments were compared to the respective DMSO control. Similar approaches, where treatments are compared with solvent control have previously been reported in the literature (Kamel et al, 2012;Lacaze et al, 2015;Oliveira et al, 2016a). The percentage of DMSO used in the solvent controls was 0.01 % with the single exception of the D. magna capsaicin series where a higher solvent exposure percentage of 0.03 % was used.…”

“…Tralopyril is thought to uncouple the mitochondrial oxidative phosphorylation by dissipating the proton gradient necessary for ATP formation (European Chemicals Agency, 2014;Oliveira et al, 2016a). Not surprisingly, tralopyril had an effect on the regulation of the cytochrome b-c1 complex subunit 8 protein.…”