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Supralittoral ecosystems are among the most challenging environments for soil organisms, particularly when salinity fluctuations are involved, frequently combined with the presence of contaminants as a result of intense anthropogenic activities. Knowledge of how salinity influences the effect of contaminants in supralittoral species is crucial for determining the safety factors required when extrapolating results from optimal laboratory conditions to these natural ecosystems. The present study therefore evaluated the effects of 2 metals (copper and cadmium) and 2 organic compounds (carbendazim and 4-nonylphenol) in the absence or presence of 15‰ NaCl in the potworm Enchytraeus albidus, a model organism for ecotoxicology studies commonly found in supralittoral ecosystems, The potworms had a higher reproduction in saline soil than in control soil. Moreover, the effects of copper and carbendazim on reproduction were smaller than when they were tested in nonsaline soil. Potworms exposed to nonsaline soils also had significantly higher tissue concentrations of metals, which partly explains the effects on reproduction. The influence of salinity on effects of 4-nonylphenol was, however, less clear; effects on survival decreased in saline soil, but effects on reproduction were highest in saline soil. The latter slightly correlated with tissue concentrations of the chemical. The present study provides the first evidence that soil salinity has a significant influence on the impact of contaminants evaluated with the enchytraeid reproduction test. Environ Toxicol Chem 2015;34:2159-2166. © 2015 SETAC [ABSTRACT FROM AUTHOR]

Metal ecotoxicity to soil organisms (for example, in enchytraeids) has been addressed mainly by assessing effects on survival and reproduction, but very little is known about the underlying molecular mechanisms of responses. The main purpose of the present study was to assess and compare the transcriptional responses of Enchytraeus albidus to an essential (Zn) and a nonessential (Cd) metal. Exposure was performed with two concentrations with a known effect on reproduction (effective concentration for 50% [EC50] and 90% [EC90]) at three time points (2, 4, and 8 d). Results showed that transcriptional responses were influenced by exposure duration but, independently of that, the mechanisms of response to Cd and Zn were consistently different. Both metals affected pathways related to the regulation of gene expression, calcium homeostasis, and cellular respiration. Mechanisms of toxicity that were exclusively associated with Cd exposures were the inhibition of DNA repair and the impairment of ubiquitin-mediated proteolysis. The microarray for E. albidus was a useful tool for detecting molecular pathways affected by metal exposures. Transcriptional responses strongly correlated with known mechanisms of Cd and Zn responses in other organisms, suggesting cross-species conserved mechanisms of action. It should be highlighted not only that the authors could retrieve mechanistic information but also that genes responded within 2 to 8 d of exposure. This represents an additional advantage of using such molecular endpoints as a complement to the traditional, more time-consuming endpoints. Environ. Toxicol. Chem. 2012; 31: 2289-2299. © 2012 SETAC [ABSTRACT FROM AUTHOR]

To better understand chemical modes of action, emphasis has been given to stress responses at lower levels of biological organization. Cholinesterases and antioxidant defenses are among the most used biomarkers due to their crucial role in the neurocholinergic transmission and in cell homeostasis preventing DNA damage, enzymatic inactivation and lipid peroxidation. The main goal of this study was to investigate the effects of zinc and cadmium on survival and reproduction of E. albidus and to assess metals oxidative stress potential and neurotoxic effects at concentrations that affected reproduction. Both metals affected the enchytraeids’ survival and reproduction and induced significant changes in the antioxidant defenses as well as increased lipid peroxidation, indicating oxidative damage. This study demonstrates that determining effects at different levels of biological organization can give better information on the physiological responses of enchytraeids in metal contamination events and further unravel the mechanistic processes dealing with metal stress. [Copyright &y& Elsevier]

Abstract: Triclosan (TCS) is an antimicrobial agent which is used as a broad-spectrum bacteriostatic and found in personal care products, and due to this it is spread in the environment. Aquatic toxicity studies have been reported, but little data is available for its toxicity to terrestrial organisms. The main purpose of this study was to assess the toxicity of TCS in the terrestrial environment, using a battery of soil species, belonging to different taxonomic levels. The species included the invertebrates Eisenia andrei, Enchytraeus albidus and Folsomia candida and the plants Triticum aestivum (monocotyledonous) and Brassica rapa (dicotyledonous). For the invertebrate species the reproduction EC10s were 0.6 (E. andrei), 2 (E. albidus) and 7(F. candida) mg TCS/kg soil dry weight (DW). For plants'' emergence EC10s are 0.1 (B. rapa) and 142 (T. aestivum) TCS/kg soil DW. The calculated PNEC (Predicted No Effect Concentration) ranged between 0.0008 and 0.004mg TCS/kg (95% certainty) and between 0.04 and 0.2mg TCS/kg soil DW (50% certainty) when using the SSD (Species Sensitivity Distribution) approach; applying a safety factor to the lowest EC10 resulted in a PNEC of 0.06mg TCS/kg soil DW. [Copyright &y& Elsevier]

Abstract: Enchytraeids are typical inhabitants of many soils, contributing to vital processes of this environmental compartment. Indirectly they are involved in regulating the degradation of organic matter, as well as improving the pore structure of the soil. Due to their behaviour, they are able to avoid unfavourable environmental conditions. Avoidance tests with enchytraeids, initially developed with earthworms by several authors, are quick and easy to perform. With these tests a first assessment of the toxicity of a (contaminated or spiked) soil is possible in just 48h by using the reaction of the enchytraeids as measurement endpoint. In this period of time the organisms can choose between the control soil and the other soil (a contaminated or spiked or another soil with different physico-chemical properties). In the tests reported here, the enchytraeids were exposed to control soils spiked with the fungicides Benomyl and Carbendazim and the herbicide Phenmedipham. Several chemical concentrations were tested in order to evaluate the avoidance behaviour to toxic substances. In fact, often these short-term screening tests gave results showing avoidance at concentrations in a range similar to the acute test results but, higher than in chronic tests. Further tests are needed to decide whether the results gained in this study can be extrapolated to other chemicals. It is proposed to standardize the Enchytraeid Avoidance Test as it is currently done for the Earthworm Avoidance Test by the International Standard Organization (ISO). [Copyright &y& Elsevier]

Silver nanomaterials (AgNMs) are broadly used and among the most studied nanomaterials. The underlying molecular mechanisms (e.g. protein and metabolite response) that precede phenotypical effects have been assessed to a much lesser extent. In this paper, we assess differentially expressed proteins (DEPs) and metabolites (DEMs) by high-throughput (HTP) techniques (HPLC-MS/MS with tandem mass tags, reversed-phase (RP) and hydrophilic interaction liquid chromatography (HILIC) with mass spectrometric detection). In a time series (0, 7, 14 days), the standard soil model Enchytraeus crypticus was exposed to AgNM300K and AgNO 3 at the reproduction EC20 and EC50. The impact on proteins/metabolites was clearly larger after 14 days. NM300K caused more upregulated DEPs/DEMs, more so at the EC20, whereas AgNO 3 caused a dose response increase of DEPs/DEMs. Similar pathways were activated, although often via opposite regulation (up vs down) of DEPs, hence, dissimilar mechanisms underlie the apical observed impact. Affected pathways included e.g. energy and lipid metabolism and oxidative stress. Uniquely affected by AgNO 3 was catalase, malate dehydrogenase and ATP-citrate synthase, and heat shock proteins (HSP70) and ferritin were affected by AgNM300K. The gene expression-based data in Adverse Outcome Pathway was confirmed and additional key events added, e.g. regulation of catalase and heat shock proteins were confirmed to be included. Finally, we observed (as we have seen before) that lower concentration of the NM caused higher biological impact. Data was deposited to ProteomeXchange, identifier PXD024444. [Display omitted] • One of the most complete high-throughput data set was obtained for the environment. • Good agreement between the 3 omics layers: proteomics, metabolomics, transcriptomics. • Activated pathways were oppositely (up vs down) regulated for AgNM300K and AgNO 3. • Integration of high quality "omics" in Risk Assessment will be beneficial. [ABSTRACT FROM AUTHOR]

Amongst climate change's impacts a major concern is salinization of soils, for example due to saltwater intrusion. The aim of the present study was to investigate in a standard field soil the impacts of soil salinity increase. The purpose was to study this in two soil invertebrates that are key model ecotoxicology test-species, Enchytraeus crypticus and Folsomia candida as surrogate representatives of the soil ecosystem. The exposure followed the standard ecotoxicity OECD (Organization for Economic Cooperation and Development) test guidelines, and the assessed endpoints were survival, reproduction and size. Exposure done in LUFA 2.2 soil, spiked with 0,0.6,1,2,3,4,5,6,8 g NaCl/kg soil dry weight (DW) for E. crypticus (21 days) and 0,0.06,0.6,1,2,3,4,5,6 g NaCl/kg soil DW for F. candida (28 days). There was a similar impact for both species in terms of survival (LC 50 =4.2 g NaCl/kg soil DW), whereas at the reproductive output level of F. candida (EC 50 =2.1 g NaCl/kg soil DW) was more sensitive than E. crypticus (EC 50 =2.4 g NaCl/kg soil DW). Further, size was impacted for F. candida in a monotonic dose-response curve for both adults (EC 50 =3.5 g NaCl/kg soil DW) and juveniles (EC 50 =2 g NaCl/kg soil DW), whereas for E. crypticus there was an increase in reproductive output at lower concentrations (0.6–1 g NaCl/kg soil DW). This increased reproduction was associated with a larger size of adults within the same concentration range. Considering the prediction from the climate models, the soil invertebrate community will be affected. As upper soils are likely to have the highest salinity increase due to evaporation, soil surface species, such as the collembolan tested here, are at higher risk. Negative population effects were occurring within salinity levels predicted by climate change models. [Display omitted] • The risk of soil salinity increase was assessed in invertebrate model fauna. • Impact on survival was similar between F. candida and E. crypticus. • Higher impact on F. candida reproduction, a soil surface species. • Soil surface is predicted to be more affected by salinity than deeper soil layers. • Predictions (2060) are much higher than the tolerance for these species. [ABSTRACT FROM AUTHOR]

Energy budget studies offer important information in terms of organisms' fitness and this has become an increasingly common stress marker. The method is well developed but the issue of food supply (addition or not) during exposure is not consensual. Moreover, chemicals such as cadmium (Cd) are known to affect food uptake, e.g. via feeding inhibition, hence energy budget results could be because of decreased uptake and not direct toxicity. On the other hand, food deprivation can be a stressor itself and bias results. In the present study we compared exposure with (F) and without food (NF) along time (2, 4 and 8 days). The Cellular Energy Allocation (CEA) method was used to study the effects of Cd in the soil standard species Enchytraeus albidus (Oligochaeta). In control conditions (un-spiked soil), carbohydrate and lipid budgets were mobilized in NF. When testing Cd, variations in carbohydrates and lipid budgets depend on the presence of food and time of exposure. The main hypothesized mechanisms triggered by Cd exposure were similar (i.e. induction of protein synthesis and increase in energy consumption). Differences between F and NF over time indicate that the process of mobilization/preservation of energy reserves depends on the food/energy intake (e.g. in Cd exposed organisms, mobilization of proteins occurred within 2 days when food was present, while in the absence of food carbohydrate and protein budgets were mobilized from 2 to 4 days). Comparisons between F-NF studies should not be done directly. Moreover, we recommend exposure without food because it allows a better discrimination of effects (in particular within periods of exposure). [ABSTRACT FROM AUTHOR]

Toxicokinetics information is key to understanding the underlying intoxication processes, although this is often lacking. Hence, in the present study the toxicokinetics of copper (Cu) and cadmium (Cd) was assessed in the soil invertebrate Enchytraeus crypticus. The animals were exposed in LUFA 2.2 natural soil spiked to the estimated EC 20 for reproduction effects in the Enchytraeid Reproduction Test (ERT), i.e. 80 mg Cu/kg soil Dry Weight (DW) and 20 mg Cd/kg soil DW. Tests followed the OECD guideline 317, including a 14-day uptake phase in spiked soil followed by 14 days elimination in clean soil, with samplings at days 0, 1, 2, 4, 7, 10, and 14. Exposure to Cu showed fast uptake, reaching a steady state after approx. 7 days, whereas for Cd, internal concentration increased and did not reach a clear steady state even after 14 days. When transferred to clean soil, Cu was rapidly eliminated returning to initial levels, while Cd-exposed animals still contained increased residue levels after 14 days. These differences in toxicokinetics have consequences for the toxicity and toxicodynamics and are indicative of the way essential and non-essential elements are handled by enchytraeids, likely also other soil invertebrates. This argues for the relevancy of longer exposure testing for elements like Cd compared to Cu, where phenotypical effects can well occur later at non-tested periods, e.g. after the 21 days' duration of the standard ERT using E. crypticus. [ABSTRACT FROM AUTHOR]

Certain invertebrates (and vertebrates) are able to regenerate lost body parts. In the present study we investigated if Enchytraeus crypticus (Oligocheata), a species used for standard ecotoxicological testing, shows regeneration ability. Artificial amputation was induced. The results showed that regeneration occurs for this species, this being promoted by the presence of a mass of undifferentiated cells (blastema) in the wound site. This only occurred in the anterior fragment resulting in the posterior regeneration (formation of the tail), i.e. the posterior fragment does not regenerate the head and degenerates. The regenerated organisms were tested for fertility, which was confirmed. This is an important knowledge and ecological feature, E. crypticus has an additional survival strategy. Further, given this is an ecotoxicological model species and the possible implications thereof – E. crypticus can fragment and regenerate hence survival results may include this occurrence. [ABSTRACT FROM AUTHOR]

Abstract: Cellular energy allocation (CEA) is a measure of the energy status of an organism. The effects of Cd and Zn (reproduction EC50s and EC90s) on the total energy budget of Enchytraeus albidus (Oligochaeta) were assessed through CEA determination, over periods of time from 0 to 8d. Results showed reduction on the energy reserves for both metals after 2d exposure. Lipids were the first reserves to be used and carbohydrates were reduced exclusively after Cd exposure. Electron transport system (ETS) activities were enhanced, suggesting increased metabolism and higher energy requirements for metal detoxification. This was supported by previous results at transcription level, where an up-regulation of genes involved in the mitochondrial oxidative phosphorylation was verified. Additionally, the reduction of CEA may be related with the decrease on the reproductive output. These results showed the relevance of integrating various endpoints, which enabled an overview of various processes and to unravel mechanisms of action of chemicals. [Copyright &y& Elsevier]