Pollution and Environmental Toxicology


Delayed effects of an endocrine disruptor

Voisin AS, Ulloa VS, Stockwell P, Chatterjee A, Silvestre F. 2020. Genome-wide DNA methylation of the liver reveals delayed effects of early-life exposure to 17-α-ethinylestradiol in the self-fertilizing mangrove rivulus. Preprints. DOI: 10.22541/au.159310037.71467325.

Early-life exposure to environmental stressors, encountered during the sensitive period of embryogenesis or in juveniles, can be critical in shaping the long-term control of tissue physiology and homeostasis. Identifying the molecular mechanisms is important to understand the long-term effects of toxicants in humans and wildlife. DNA methylation could mediate long-term effects of sub-toxic developmental exposure to xenobiotics and play a role in the etiology of diseases (cancer, obesity, cardiovascular disease, diabetes, hypertension, and neurodegenerative disorders), acting as a long-term memory of past exposures. This study exposed hatchlings of an isogenic lineage of the self-fertilizing fish mangrove rivulus to an EDC, an endocrine disrupting chemical (17-α-ethinylestradiol, a synthetic estrogen, that is used in oral contraceptive pills and released into the environment). After a recovery period, reduced representation bisulfite sequencing (RRBS) was performed on the liver. Gene ontology analysis revealed networks involved in lipid metabolism, cellular processes, connective tissue function, molecular transport and inflammation. Results provide further evidence on the capacity of EDCs to alter the methylome and shows that these changes can be apparent several months after the exposure, supporting the hypothesis of possible long-term modulation of gene expression through epigenetics.

Pesticides in freshwater food webs

Zhao Q, De Laender F, Van den Brink PJ. 2020. Community composition modifies direct and indirect effects of pesticides in freshwater food webs. Science of The Total Environment 739:139531. DOI: 10.1016/j.scitotenv.2020.139531.

For environmental risk assessment, the effects of pesticides on aquatic ecosystems are often assessed based on single species tests, disregarding the potential influence of community composition. Here, the influence of changing the horizontal (the number of species within trophic levels) and vertical composition (number of trophic levels) on the ecological effects of two pesticides is investigated, which target producers and herbivores, respectively. The study shows that changing horizontal composition can both increase and decrease the effects of the selected pesticides, while changing vertical composition by adding number of trophic levels always increased these effects. Therefore, single species sensitivity will not always represent a worst-case estimate of ecological effects. Protecting the most sensitive species may not ensure protection of ecosystems.

Neurotoxins & mangrove rivulus brain

Carion A, Markey A, Hétru J, Carpentier C, Suarez-Ulloa V, Denoël M, Earley RL, Silvestre F. 2020. Behavior and gene expression in the brain of adult self-fertilizing mangrove rivulus fish (Kryptolebias marmoratus) after early life exposure to the neurotoxin β-N-methylamino-L-alanine (BMAA). NeuroToxicology. DOI: 10.1016/j.neuro.2020.04.007.

BMAA, a neurotoxin naturally produced by cyanobacteria, diatoms and dinoflagellates, is a serious environmental and health threat, especially during acute blooms, which are becoming more frequent. This neurotoxin is implicated in several neurodegenerative diseases in humans through contaminated water or food consumption. This study investigates the delayed effects of a neurotoxic compound and their underlying mechanisms. The mangrove rivulus fish used as model species is able to self-fertilize and to produce isogenic lineages permitting explicit examination of environmental effects on the phenotype by reducing the genetic “noise “in the experiment. No delayed effects of BMAA on growth, reproduction, boldness and aggressiveness behavioural traits were observed. But the study revealed that BMAA can have long-lasting effects on the brain that are suspected to affect phenotypic traits with aging.

Line shape parameters for the H2O-N2 collision system

Vispoel B, Cavalcanti JH, Paige ET, Gamache RR. 2020. Vibrational dependence, temperature dependence, and prediction of line shape parameters for the H2O-N2 collision system. Journal of Quantitative Spectroscopy and Radiative Transfer 253:107030. DOI: 10.1016/j.jqsrt.2020.107030.

Water vapor can be seen throughout the universe (planets, comets, asteroids, dwarfs and cold stars). It is a major absorber of infrared radiation. On Earth, water vapor dominates the infrared spectrum. The study and modeling of atmospheric spectra requires a precise knowledge of spectroscopic data.
In a recent work, Vispoel et al. [JQSRT 228, 79(2019)] optimized the intermolecular potential used in the Modified Complex Robert-Bonamy (MCRB) formalism for the H2O-N2 molecular system, and made calculations for the rotation and ν2 bands. In this work, calculations were performed for 7272 transitions of 11 bands (0-4 vibrational quanta exchanged in the ν1, ν2 and ν3 bands) at 13 temperatures between 200 and 3000K. The temperature dependence was determined using the Gamache-Vispoel model [JQSRT 217, 440(2018)].
The large quantity of data allowed the development of a routine that can predict the half-width, line shift, and their temperature dependence for transitions not yet studied. The algorithm yields to line shape parameters with much smaller uncertainty than other methods (ad hoc polynomials or J” averaged values). A line file based on the 2020 update to the HITRAN2016 water vapor line file was created with N2 as the broadening species. These data are useful for combustion studies and as a first step to determine air-broadening for the HITRAN and GEISA databases.

Unified study of multiple stressors

Orr JA, Vinebrooke RD, Jackson MC, Kroeker KJ, Kordas RL, Mantyka-Pringle C, Van den Brink PJ, De Laender F, Stoks R, Holmstrup M, Matthaei CD, Monk WA, Penk MR, Leuzinger S, Schäfer RB, Piggott JJ. 2020. Towards a unified study of multiple stressors: divisions and common goals across research disciplines. Proceedings of the Royal Society B: Biological Sciences 287:20200421. DOI: 10.1098/rspb.2020.0421.

Anthropogenic environmental changes, or ‘stressors’, increasingly threaten biodiversity and ecosystem functioning worldwide. Multiple-stressor research is a rapidly expanding field of science that seeks to understand and ultimately predict the interactions between stressors. Reviews and meta-analyses of the primary scientific literature have largely been specific to either freshwater, marine or terrestrial ecology, or ecotoxicology. This cross-disciplinary study reviews the state of knowledge within and among these disciplines to highlight commonality and division in multiple-stressor research. The review further uses quantitative bibliometric analysis to identify the division between disciplines and link previously disconnected research communities. Towards a unified research framework, the shared goal of increased realism through both ecological and temporal complexity is discussed, with the overarching aim of improving predictive power.

Oxidative stress in aquatic organisms

Silvestre F. Signaling pathways of oxidative stress in aquatic organisms exposed to xenobiotics. Journal of Experimental Zoology Part A: Ecological and Integrative Physiology n/a. DOI: 10.1002/jez.2356.

Oxidative stress is frequently generated in cells of organisms exposed to environmental pollutants. The production of reactive oxygen species (ROS) can have either adaptive or maladaptive consequences for the organism as well as for the entire population. This review shows that important pathways described in mammals are also activated in aquatic species in response to a variety of xenobiotics. There also exist crosstalks between these pathways, which together activate a complex cellular antioxidative machinery in response to different stressors. Efforts should be made to extend the number of studied species and better characterize the organ‐dependency and age‐dependency of the responses. However, the huge number and variety of chemicals present in the environment makes the task difficult. Deciphering these key pathways can help to understand the mode of action of pollutants and consequently help to assess the environmental risk in aquatic ecosystems.

Chemical stress & freshwater invertebrates

Van den Berg SJP, Rendal C, Focks A, Butler E, Peeters ETHM, De Laender F, Van den Brink PJ. 2020. Potential impact of chemical stress on freshwater invertebrates: A sensitivity assessment on continental and national scale based on distribution patterns, biological traits, and relatedness. Science of The Total Environment 731:139150. DOI: 10.1016/j.scitotenv.2020.139150.

Current chemical risk assessment approaches rely on a standard suite of test species to assess toxicity to environmental species. However, these are usually not representative of all species present in ecosystems with regards to their sensitivity to stressors. Here, predictive sensitivity models were developed by combining species-specific information on acute chemical sensitivity (LC50 and EC50), traits, and taxonomic relatedness. These models were applied at two spatial scales to reveal spatial differences in the sensitivity of species assemblages towards two chemical modes of action (MOA): narcosis and acetylcholinesterase (AChE) inhibition. Hotspots of species sensitive to chemical stressors were identified at two spatial scales. Crucial technological advances are required for the successful application of the proposed methodology to invertebrate scenarios, which remain underrepresented in global conservation priorities.

Spectroscopy to measure temperature dependence

Leonis S, Lepère M. 2020. N2-collisional broadening coefficients of lines in the ν2 band of chloromethane from low to room temperatures. Journal of Molecular Spectroscopy 369:111269. DOI: 10.1016/j.jms.2020.111269.

To understand climate change, it is necessary to understand and quantify the evolution of pollutants in our atmosphere, such as the chloromethane. Accurate spectroscopic parameters of such greenhouse gases, and in particular, their collisional broadening coefficients help us to characterize our atmosphere. This study measures the N2-broadening coefficients in the band of chloromethane at low and room temperatures with the help of high-resolution diode-laser spectroscopy. Experimental line profiles were fitted with different line shape models.

Anti–inflammatory and antioxidant for Zebrafish

Nguyen TH, Le HD, Kim TNT, The HP, Nguyen TM, Cornet V, Lambert J, Kestemont P. 2020. Anti–Inflammatory and Antioxidant Properties of the Ethanol Extract of Clerodendrum Cyrtophyllum Turcz in Copper Sulfate-Induced Inflammation in Zebrafish. Antioxidants 9:192. DOI: 10.3390/antiox9030192.

Oxidative stress and inflammation contribute to the pathogenesis of many chronic diseases. This study tests the plant Clerodendrum cyrthophyllum (Verbenaceae) for its antioxidant and/or anti‐inflammatory activities, which could provide a useful treatment of pathologies. The plant is used in Vietnamese traditional medicine against inflammation of the throat, rheumatic arthritis, etc. This study tested its antioxidant and anti‐inflammatory effects on zebrafish. Inflammation was induced through an oxidative stress reaction to copper (CuSO4) exposure. Preceding treatment with an ethanol extract of C. cyrtophyllum leaves showed protective activity against oxidative stress as measured via fluorescent intensity. Further, genes related to inflammatory processes were downregulated by C. cyrtophyllum, suggesting its usefulness to treat inflammatory diseases.

Anti-inflammatory properties of Clerodendrum cyrtophyllum

Nguyen TH, Nachtergael A, Nguyen TM, Cornet V, Duez P, Muller M, Ly Huong DT, Kestemont P. 2020. Anti-inflammatory properties of the ethanol extract from Clerodendrum cyrtophyllum Turcz based on in vitro and in vivo studies. Journal of Ethnopharmacology 254:112739. DOI: 10.1016/j.jep.2020.112739.

Another test of the anti-inflammatory properties of the Verbenaceae plant Clerodendrum cyrtophyllum, again with zebrafish as in vitro and in vivo model. Colorimetric methods and HPTLC revealed high phenolic and flavonoid contents in the ethanol extract of the plant. The ethanol extract reduced the expression of several inflammatory genes and increase the expression of an anti-inflammatory cytokine gene. The results confirm the use in traditional medicine of this plant in Asia to treat inflammations and proposes the raw ethanol extract of the leaves as potential treatment.

Biomimetic hybrid membranes

Molina BG, Lopes-Rodrigues M, Estrany F, Michaux C, Perpète EA, Armelin E, Alemán C. 2020. Free-standing flexible and biomimetic hybrid membranes for ions and ATP transport. Journal of Membrane Science 601:117931. DOI: 10.1016/j.memsci.2020.117931.

Biomimetics takes advantage of the natural structures found in biological systems, permitting a nanoscopic development of functional materials. Many of such nanomaterials based on proteins (e.g. filtration devices, nanosensors) usually require nanoscopic pathways for the passage of ions and small molecules. Porins, i.e. outer membrane proteins (OMPs) found in gram-negative bacteria and mitochondria, can naturally form β-barrel channels. They act as gates of the cell membrane. Here, for the first time, a free standing and conducting polymeric membrane with porin protein immobilized has been developed and proved to be efficient for transport of ATP and NaCl. Thus, the hybrid system obtained by combining synthetic polymers and porin proteins is well-suited for the development of flexible membrane biosensors with fully functional transmembrane ion channels. The new platform is fully free-standing and flexible and can be applied in many biomedical technologies, opening new frontiers for the future development of high-throughput screening assays.


Characterising plant channels

Lopes‐Rodrigues M, Matagne A, Zanuy D, Alemán C, Perpète EA, Michaux C. Structural and functional characterization of Solanum tuberosum VDAC36. Proteins: Structure, Function, and Bioinformatics n/a. DOI: 10.1002/prot.25861.

The voltage‐dependent anion channel (VDAC) protein family plays a central role in all eukaryotic cells. It forms water‐filled channels in the mitochondria outer membrane and diffuses essential metabolites such as NADH and ATP. Compared with their mammalian homologues, little is known about the structural and functional properties of plant VDACs. Here, one of the two VDACs isoforms of Solanum tuberosum, stVDAC36, has been successfully overexpressed and refolded by a method, that has been established by the CPB lab of UNamur. This is demonstrated by the information on its secondary and tertiary structure gathered from circular dichroism and intrinsic fluorescence. Cross‐linking and molecular modelling studies have evidenced the presence of dimers and tetramers, and they suggest the formation of an intermolecular disulphide bond between two stVDAC36 monomers. The pore‐forming activity was also assessed by liposome swelling assays, indicating a typical pore diameter between 2.0 and 2.7 nm. Finally, insights about the ATP binding inside the pore are given by docking studies and electrostatic calculations.

Line shift coefficients of methane

Vispoel B, Lepère M. 2019. N2-collisional shift coefficients of lines in the ν3 band of methane from low to high temperatures. Journal of Quantitative Spectroscopy and Radiative Transfer 239:106654. DOI: 10.1016/j.jqsrt.2019.106654

Though methane is a minor constituent of the Earth’s atmosphere, its effect on climate and atmospheric chemistry is important. Methane is also present in atmospheres of several planets (e.g. Mars) and stellar objects and could indicate the presence of life. Retrievals of atmospheric spectra are very sensitive to the spectroscopic parameters, especially to half-width and line shifts that are hardly known. This study measures line shift coefficients of methane perturbed by nitrogen using a dual beam tuneable diode-laser spectrometer of high resolution. The measurements were performed from low (123 K) to high (598 K) temperatures. This large temperature range allowed to study the temperature dependence of the collisional line shift coefficients using 2 empirical laws (the power law and the linear law) as well as the new physics based double power law (DPL). The results show that the DPL reproduces more accurately the evolution of the line shift with the temperature. An accurate knowledge of the temperature dependence of line shape parameters is crucial for the remote sensing of the Earth's or planetary atmospheres.

Temperature dependence of line shape parameters

Stolarczyk N, Thibault F, Cybulski H, Jóźwiak H, Kowzan G, Vispoel B, Gordon IE, Rothman LS, Gamache RR, Wcislo P. 2019. Evaluation of different parameterizations of temperature dependences of the line-shape parameters based on ab initio calculations: case study for the HITRAN database. Journal of Quantitative Spectroscopy and Radiative Transfer:106676. DOI: 10.1016/j.jqsrt.2019.106676.

The knowledge of accurate molecular spectroscopic parameters is essential to interpret and model spectra of terrestrial and planetary atmospheres. These parameters need to be known with a high precision as well as their evolution with temperature (for instance the temperature on Uranus is 55K while hot Jupiter planets can reach 1000 – 2500K). Within all the needed data, the half-width and line shift are crucial parameters that, traditionally, had temperature dependencies represented by empirical laws (“4TR” in the figure). Recently, a physics based law (Double Power Law - DPL) has been developed and adopted by the HITRAN (a spectroscopic database) committee. This article compares the performance of the empirical laws and the DPL to reproduce large amounts of calculated data. It shows that the new law results in better overall approximation of the temperature evolution of the spectroscopic parameters, requires less parameters and its structure is much simpler and more self-consistent than the empirical ones. Finally, the paper recommends the usage of the double power law and presents DPL parametrizations for the HITRAN database. These results are crucial for remote sensing of our atmosphere and determination of the vertical concentration profiles of pollutants.

Predict the concentration of methane

Gamache RR, Rey Michaël, Vispoel B, Tyuterev VG. 2019. Reduced Matrix Elements for collisionally induced transitions of 12CH4. Journal of Quantitative Spectroscopy and Radiative Transfer. DOI: 10.1016/j.jqsrt.2019.06.010.

To perform inversion of atmospheric spectra and precisely measure the concentration of methane in the Earth’s atmosphere or others (like Mars or Titan), it is required to characterize the infrared absorption by the gases present in atmospheres. This is done through the determination of the spectroscopic parameters of infrared absorption lines for each gas. This determination is usually realized experimentally for some lines, while calculations are needed for all lines. They can be made by semi-classical theory that requires a good knowledge of the interaction processes between molecules. In this work, the Reduced Matrix Elements for collisional induced transitions were computed from ab initio wave function for methane. They are an important part of the semi-classical line shape calculation. The obtained results will have an important environmental input since they will improve the knowledge of the methane in our atmosphere.

Predict the sensitivity of macroinvertebrates

Van den Berg SJP, Baveco H, Butler E, De Laender F, Focks A, Franco A, Rendal C, Van den Brink PJ. 2019. Modeling the Sensitivity of Aquatic Macroinvertebrates to Chemicals Using Traits. Environmental Science & Technology 53:6025–6034. DOI: 10.1021/acs.est.9b00893.

In the environmental risk assessment of chemicals, the determination of thresholds is essential. Usually, a few standard species are tested for effects of toxicants and results are then extrapolated to other species. The presented modelling tool allows to determine a ranking of the sensitivity of macroinvertebrates and provides thus a predictive trait model.

Stress, diversity & productivity

De Raedt J, Baert JM, Janssen CR, De Laender F. 2019. Stressor fluxes alter the relationship between beta-diversity and regional productivity. Oikos 0. DOI: 10.1111/oik.05191.

Dispersal of organisms can influence beta‐diversity and also regional productivity in heterogeneous environments. At the same time, the release of chemicals is stressful to ecosystems and can effect dispersal, but HOW? Experiments with two marine micro‐algae communities were conducted to shed light on this relationship. Similar to other studies, a positive relationship of beta-diversity and productivity was found in the absence of a stressor. However, when a stressor flux was present, this relationship became negative.



Lopes-Rodrigues M, Zanuy D, Alemán C, Michaux C, Perpète EA. 2018. 3D structure of a Brucella melitensis porin: molecular modelling in lipid membranes. Journal of Biomolecular Structure and Dynamics 0:1–13. DOI: 10.1080/07391102.2018.1529627.

Dye removal with natural clay

Chargui H, Hajjaji W, Wouters J, Yans J, Jamoussi F. 2018. Direct Orange 34 dye fixation by modified kaolin. Clay Minerals 53:271–287. DOI: 10.1180/clm.2018.18.

Direct Orange 34 is a highly toxic dye used in textile industries in Tunisia. Dye wastewater is carcinogenic, toxic and non-biodegradable, thus causing huge environmental problems. Due to their colloidal properties, clay minerals are efficient adsorbents and can effectively remove such dyes from aqueous solutions. Such naturally available clays have further the advantage that they are low-cost, abundant and non-toxic. This study tested the adsorption behaviour of modified (acid-activated and Fe-impregnated) kaolinite-rich clays from a local mine. The clays showed satisfactory affinity for adsorbing this reactive dye.

Review on neurotoxicity of chemicals

Legradi JB, Di Paolo C, Kraak MHS, van der Geest HG, Schymanski EL, Williams AJ, Dingemans MML, Massei R, Brack W, Cousin X, Begout M-L, van der Oost R, Carion A, Suarez-Ulloa V, Silvestre F, Escher BI, Engwall M, Nilén G, Keiter SH, Pollet D, Waldmann P, Kienle C, Werner I, Haigis A-C, Knapen D, Vergauwen L, Spehr M, Schulz W, Busch W, Leuthold D, Scholz S, vom Berg CM, Basu N, Murphy CA, Lampert A, Kuckelkorn J, Grummt T, Hollert H. 2018. An ecotoxicological view on neurotoxicity assessment. Environmental Sciences Europe 30:46. DOI: 10.1186/s12302-018-0173-x.

Thirtyeight recognized scientists emphasize the necessity to assess the thousands of chemicals that enter the natural environment due to human activities. Potential neurotoxicity has been predicted for 30 000 compounds. These can trigger diseases later in life, such as neurodegenerative diseases. Chronic pollution is to be considered as part of global change, such as climate change and biodiversity loss. A critical overview of the state of the art of hazard characterization, effects, bioassays and chemical approaches regarding neurotoxicity in organisms as well as for ecosystems.

Mangrove rivulus & endocrin disruptors

Voisin A-S, Kültz D, Silvestre F. 2018. Early-life exposure to the endocrine disruptor 17-α-ethinylestradiol induces delayed effects in adult brain, liver and ovotestis proteomes of a self-fertilizing fish. Journal of Proteomics. DOI: 10.1016/j.jprot.2018.12.008.

If you expose mangrove rivulus during early life stages to an endocrine disrupting chemical, their protein expression profile in brain, liver and gonads is changed in adult fish, 5 months after the end of the exposure. This study uses a modern proteomic workflow. It shows that early life stages are critical windows extremely sensitive to environmental pollutants. These can trigger molecular changes later in life, and possibly explain latent diseases.

Mangrove rivulus & neurotoxins

Carion A, Hétru J, Markey A, Suarez-Ulloa V, Silvestre F. 2018. Behavioral effects of the neurotoxin ß-N-methylamino-L-alanine on the mangrove rivulus (Kryptolebias marmoratus) larvae. Journal of Xenobiotics. DOI: 10.4081/xeno.2018.7820.

A first article based on preliminary data of two master students, Julie Hetru and Angèle Markay. The mangrove rivulus successfully served as an ecotoxicological model to assess the impacts of neurotoxins during fish development on behaviour at adult stage. Further long term effects (latent effects in adults and across generations) and the molecular mechanisms of neurotoxicity (epigenetics) are still under investigation.

Biomimetics: Porins & ~Natural Environment

Puiggalí-Jou A, Pawlowski J, del Valle LJ, Michaux C, Perpète EA, Sek S, Alemán C. 2018. Properties of Omp2a-Based Supported Lipid Bilayers: Comparison with Polymeric Bioinspired Membranes. ACS Omega 3:9003–9019. DOI: 10.1021/acsomega.8b00913.

This work focusses on the protein Omp2a in an ambient that is more similar to nature: a supported lipid bilayer (~ a planar in vitro assembly of lipids sitting on a solid support). The nanomechanical properties (elasticity, adhesion forces, deformation) and functionality of the resulting – more natural - bioinspired membrane was compared with those of polymeric nanomembranes (NMs). Results show that the protein is softer and more flexible than the lipid bilayer, allowing the passage of molecules with varying sizes and shapes. This character could truly mimic biological attributes. For technological applications on the other hand, the lipid bilayer is less suited than polymeric NMs due to its lower mechanical strength observed.

Biomimetics: Porins & Temperature

Lopes-Rodrigues M, Puiggalí-Jou A, Martí-Balleste D, del Valle LJ, Michaux C, Perpète EA, Alemán C. 2018. Thermomechanical Response of a Representative Porin for Biomimetics. ACS Omega 3:7856–7867. DOI: 10.1021/acsomega.8b00463.

Membrane proteins play a key role in many biological processes, such as cell recognition, signal transmission, enzymatic reactions, and transport of metabolites. Porins are proteins that can be immobilized onto outer membranes or also inside synthetic pores to fabricate smart biomimetric nanomembranes. They form water-filled open channels (β barrels) and allow the passive penetration of hydrophilic molecules, having thus the capacity to exchange ions or small nutrients. Of course, the nanostructure of the porin aggregate plays a crucial role in its functionality. The size and shape of these structures is influenced by the chemical environment. Here, the response of Omp2a, an often-used porin, to temperature increase is measured and compared to conventional proteins.

Drugs & Rainbow Trout

Schmitz M, Beghin M, Mandiki SNM, Nott K, Gillet M, Ronkart S, Robert C, Baekelandt S, Kestemont P. 2018. Environmentally-relevant mixture of pharmaceutical drugs stimulates sex-steroid hormone production and modulates the expression of candidate genes in the ovary of juvenile female rainbow trout. Aquatic Toxicology 205:89–99. DOI: 10.1016/j.aquatox.2018.10.006.

Pharmaceutical drugs can be found almost everywhere in our environment. Here, female rainbow trout were exposed to a mixture of pharmaceuticals as detected in the river Meuse (paracetamol, diclophenac, etc.). Elevated levels of sex hormones and of genes involved in steroidogenesis were found, which might lead to premature growth of previtellogenic follicles in the ovaries of pre-pubertal female fish. The effects appeared to be concentration-dependent, which stresses the importance of including environmental exposure concentrations in toxicological studies.

Triclosan & Zebrafish

Falisse E, Ducos B, Stockwell PA, Morison IM, Chatterjee A, Silvestre F. 2018. DNA methylation and gene expression alterations in zebrafish early-life stages exposed to the antibacterial agent triclosan. Environmental Pollution 243:1867–1877. DOI: 10.1016/j.envpol.2018.10.004.

Aim of this study was to identify the epigenetic effects of an exposure to a common pollutant (the antibacterial agent Triclosan) during the development of zebrafish. Triclosan is commonly used in soaps, toothpastes and cosmetics and is suspected to induce some endocrine disruption. DNA methylation, a common epigenetic mechanism, was affected by exposure to 50 and 100 µg/L of Triclosan. However, each exposure concentration showed a specific alteration pattern and was correlated to specific phenotypic effects. Further observation was that differential DNA methylation is mainly reported in introns and intergenic regions, the former being correlated to gene expression. Surprisingly, very few significant effects have been found in promotor regions. Further studies will investigate the possible long-term consequences of these alterations and the possible implications in terms of fitness and adaptation to environmental pollutants.

Biodiversity and ecosystem functioning under environmental stress

Baert, JM, Eisenhauer, N, Janssen, CR, De Laender, F (2018), Biodiversity effects on ecosystem functioning respond unimodally to environmental stress. Ecology Letters doi:10.1111/ele.13088

Understanding how biodiversity (B) affects ecosystem functioning (EF) is essential for assessing the consequences of ongoing biodiversity changes. Environmental conditions impact on these BEF relationships. With the help of a community model stemming form game‐theory, it is shown that along environmental stress gradients, the response of BEF interactions is unimodal. Depending on how stress affects species interactions, the ecological mechanisms underlying this response may vary. A global dataset of 44 experiments that cross biodiversity with environmental conditions was then analysed. The analysis confirms that at intermediate levels of environmental stress, the effect of biodiversity on ecosystem functioning tends to be greater. Results suggest that increases in stress from ongoing global environmental changes may amplify the consequences of biodiversity changes.

Chemical stress effects marine food webs

Mensens, C, De Laender, F, Janssen, CR, Rivera, FC, Sabbe, K and De Troch, M (2018), Selective and context‐dependent effects of chemical stress across trophic levels at the basis of marine food webs. Ecological Applications, 28: 1342-1353. doi:10.1002/eap.1737

Human activities and stressors increasingly impact the functioning of marine food webs, but are seldom included in ecological study designs. Further, diet quality is rarely highlighted in food web studies in a stress context, as opposed to diet quantity. This article measures the effects of metal and pesticide stress (copper and atrazine) on a benthic intertidal diatom community and how this impacts on biomass (diet quantity) and lipid (diet quality) production. Pesticides changed the community structure (selective effects) of diatoms to lipid-poor species, reducing diatom diet quality by up to 75%. Further, at high copper concentrations, diatoms lost 40% of their lipids (context‐dependent effect). These changes in diet quality led to consequences for the copepod grazers feeding on diatoms, even at stress levels where no changes in diatom lipid content had been detected.

Effects of an organic-inorganic chemical mixture on marine plankton

Filimonova, V, De Troch, M, Gonçalves, F, Marques, JC, Marques, SM, Gonçalves, AMM, & De Laender, F 2018, ‘Effects of a herbicide and copper mixture on the quality of marine plankton’, Ecotoxicology and Environmental Safety, vol. 156, pp. 9–17, doi: 10.1016/j.ecoenv.2018.02.038

Pesticides and metals are often used in agriculture and are therefore often simultaneously discharged to nearby estuarine and marine areas with unknown effects on food quality of aquatic organisms. This study investigates the effects of a mixture of copper (inorganic) and a herbicide (organic) on the quality of diatoms and copepods, which are highly important food sources for fish and marine animals. The effects of the metal-herbicide mixture on food quality of plankton were non-additive and the contaminants mixture had a stronger effect on food quality than single exposure. The species from a higher trophic level (i.e. copepods) was most sensitive to the chemical stressors.

Light shed on peptide-surfactant interactions

Roussel, G, Caudano, Y, Matagne, A, Sansom, MS, Perpète, EA, & Michaux, C 2018, ‘Peptide-surfactant interactions: A combined spectroscopic and molecular dynamics simulation approach’, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 190, pp. 464–470, doi: 10.1016/j.saa.2017.09.056

Sodium dodecyl sulphate (SDS) or sodium lauryl sulfate (SLS) is a highly effective anionic surfactant used in many cleaning and hygiene products (floor cleaners, shampoo, toothpaste,…). Other than classical chemical denaturants, it can already denature proteins at extremely weak (millimolar!) concentrations.  Despite its universal application, the exact nature of the protein-detergent interactions is still not thoroughly understood nor controlled. This study unravels at atomic resolution the effect of SDS detergent on the structure of two model peptides using a combined spectroscopic and computational approach.

Control the growth of germanium nanocrystals

Barba, D, Wang, C, Nélis, A, Terwagne, G & Rosei, F 2017, ‘Blocking germanium diffusion inside silicon dioxide using a co-implanted silicon barrier’, Journal of Applied Physics, vol. 123, no. 16, p. 161540. DOI: 10.1063/1.5002693

Germanium nanocrystals (Ge-NCs) are environmentally friendlier alternatives to classical ones containing toxic elements (e.g. mercury) and thus attract renewed scientific interest. Controlling their size defines many of their photophysical properties, which may improve the performance of numerous devices like solar cells, photodetectors, and lithium ion batteries.
This paper investigates the effect of co-implanting a silicon sublayer on the thermal diffusion of germanium ions implanted into SiO2. Although this technique affects the crystallinity of the formed Ge-NCs, it controls the spatial distribution of Germanium. This effect can be used to produce size-selective and depth-ordered nanostructured systems.

A special diet can improve the immune system of rainbow trout

Cornet, V, Ouaach, A, Mandiki, SNM, Flamion, E, Ferain, A, Van Larebeke, M, Lemaire, B, Reyes López, FE, Tort, L, Larondelle, Y & Kestemont, P 2018, ‘Environmentally-realistic concentration of cadmium combined with polyunsaturated fatty acids enriched diets modulated non-specific immunity in rainbow trout’, Aquatic Toxicology, vol. 196, pp. 104–116. https://doi.org/10.1016/j.aquatox.2018.01.012

 Fish are more and more exposed to stressors such as pollution, overcrowding and pathogen risks. Cadmium for example is a non-essential metal that often ends up in our rivers and lakes. Growing healthy fish in such contaminated environments depends among others on their nutrition. Scientists are therefore searching for food components, for example vegetable oils, that are able to improve fish health and growth. This publication shows that Cadmium (in concentrations as found in nature) can strongly impact the immune system of rainbow trout (Oncorhynchus mykiss). A specific diet, enriched with polyunsaturated fatty acids improved fish growth, provided protection against oxidative stress and stimulated their immunity

Bioinspired membranes: Learn from nature

Lopes-Rodrigues, M, Triguero, J, Torras, J, Perpète, EA, Michaux, C, Zanuy, D & Alemán, C 2018, ‘Influence of the surrounding environment in re-naturalized β-barrel membrane proteins’, Biophysical Chemistry, vol. 234, pp. 6–15. DOI: 0.1016/j.bpc.2017.12.003

 Porins, proteins acting as pores mediating the diffusion of small molecules through the membrane, are excellent candidates to design bioinspired membranes. These are powerful since, once immobilized into polymeric matrices, they can selectively separate undesired substances from liquid materials and for example be used for water purification. However, the fabrication of these protein-integrated devices depends on the stability of the porin structure, which can be spoiled or supported by the surrounding environment as reported in this publication.

Mercury affects the brain of peacock blennies

Naïja, A, Kestemont, P, Chénais, B, Haouas, Z, Blust, R, Helal, AN & Marchand, J 2018, ‘Effects of Hg sublethal exposure in the brain of peacock blennies Salaria pavo: Molecular, physiological and histopathological analysis’, Chemosphere, vol. 193, pp. 1094–1104. DOI: 10.1016/j.chemosphere.2017.11.118

Marine environments are contaminated by large amounts of toxicants including mercury (Hg). This poses a real concern for public health since the metal can accumulate and become toxic along the trophic chain. This study investigated any neurotoxic effects of Hg in the peacock blenny (Salaria pavo), a widely distributed fish at the Mediterranean and the North Atlantic coast. When individuals were exposed to a sublethal concentration of Hg their brain tissue was affected. However, previously measured Hg concentrations disappeared after several days suggesting that the brain of peacock blennies was able to detoxify the metal.

Van de Perre D, Roessink I, Janssen CR, Smolders E, De Laender F, Brink PJV den, Schamphelaere KACD. 2018. The combined and interactive effects of zinc, temperature, and phosphorus on the structure and functioning of a freshwater community. Environmental Toxicology and Chemistry 37:2413–2427. DOI: 10.1002/etc.4201.


Baert, JM, De Laender, F & Janssen, CR 2017, 'The consequences of non-randomness in species-sensitivity in relation to functional traits for ecosystem-level effects of chemicals' Environmental Science and Technology, vol 51, no. 12, pp. 7228-7235. DOI: 10.1021/acs.est.7b00527

De Hoop, L, Viaene, KPJ, Schipper, AM, Huijbregts, MAJ, De Laender, F & Hendriks, AJ 2017, 'Time-varying effects of aromatic oil constituents on the survival of aquatic species: Deviations between model estimates and observations' Environmental Toxicology & Chemistry, vol 36, no. 1, pp. 128-136. DOI: 10.1002/etc.3508

De Raedt, J, Baert, JM, Janssen, CR & de Laender, F 2017, 'Non-additive effects of dispersal and selective stress on structure, evenness, and biovolume production in marine diatom communities' Hydrobiologia, vol 788, no.1, pp. 385-396. DOI: 10.1007/s10750-016-3016-z

Di Guardo, A, Morselli, M, Morabito, G, Semplice, M, Van den Brink, PJ & De Laender, F 2017, 'European environmental scenarios of chemical bioavailability in freshwater systems' Science of the Total Environment, vol 580, pp. 1237-1246. DOI: 10.1016/j.scitotenv.2016.12.084

Falisse, É, Voisin, A-S & Silvestre, F 2017, 'Impacts of triclosan exposure on zebrafish early-life stage: Toxicity and acclimation mechanisms' Aquatic Toxicology, vol 189, pp. 97-107. DOI: 10.1016/j.aquatox.2017.06.003

Franco, A, Price, O, Marshall, S, Jolliet, O, Van den Brink, P, Rico, A, Focks, A, De Laender, F & Ashauer, R 2017, 'Towards refined environmental scenarios for ecological risk assessment of down-the-drain chemicals in freshwater environments' Integrated Environmental Assessment and Management, vol 13, pp. 233-248. DOI: 10.1002/ieam.1801

Mensens, C, De Laender, F, Janssen, CR, Sabbe, K & De Troch, M 2017, 'Different response-effect trait relationships underlie contrasting responses to two chemical stressors' Journal of Ecology, vol 105, no. 6, pp. 1598-1609. DOI: 10.1111/1365-2745.12777

Naïja, A, Kestemont, P, Chénais, B, Haouas, Z, Blust, R, Helal, AN & Marchand, J 2017, 'Cadmium exposure exerts neurotoxic effects in peacock blennies Salaria pavo' Ecotoxicology and Environmental Safety, vol 143, pp. 217-227. DOI: 10.1016/j.ecoenv.2017.05.041


Bonnineau, C, Scaion, D, Lemaire, B, Belpaire, C, Thomé, J-P, Thonon, M, Leermaker, M, Gao, Y, Debier, C, Silvestre, F, Kestemont, P & Rees, J-F 2016, 'Accumulation of neurotoxic organochlorines and trace elements in brain of female European eel (Anguilla anguilla)' Environmental Toxicology and Pharmacology, vol 45, pp. 346-355. DOI: 10.1016/j.etap.2016.06.009

De Hoop, L, Broch, O-J, Hendriks, AJ & De Laender, F 2016, 'Crude oil affecting the biomass of the marine copepod Calanus finmarchicus: comparing a simple and complex population model' Marine Environmental Research, vol 119, pp. 197–206. DOI: 10.1016/j.marenvres.2016.06.008

Dohmen, GP, Preuss, TG, Hamer, M, Galic, N, Strauss, T, van den Brink, PJ, De Laender, F & Bopp, S 2016, 'Population-level effects and recovery of aquatic invertebrates after multiple applications of an insecticide' Integrated Environmental Assessment and Management, vol 12, no. 1, pp. 67-81. DOI: 10.1002/ieam.1676

Dorts, J, Falisse, E, Schoofs, E, Flamion, E, Kestemont, P & Silvestre, F 2016, 'DNA methyltransferases and stress-related genes expression in zebrafish larvae after exposure to heat and copper during reprogramming of DNA methylation' Scientific Reports, vol 6, 34254. DOI: 10.1038/srep34254

Everaert, G, De Laender, F, Claessens, M, Baert, J, Monteyne, E, Roose, P, Goethals, PLM & Janssen, CR 2016, 'Realistic environmental mixtures of hydrophobic compounds do not alter growth of a marine diatom' Marine Pollution Bulletin, vol 102, no. 1, pp. 58-64. DOI: 10.1016/j.marpolbul.2015.11.058

Michaux, C, Roussel, G, Lopes-Rodrigues, M, Matagne, A & Perpète, EA 2016, 'Unravelling the mechanisms of a protein refolding process based on the association of detergents and co-solvents' Journal of Peptide Science, pp. 485-491. DOI: 10.1002/psc.2893

Naïja, A, Marchand, J, Kestemont, P, Haouas, Z, Blust, R, Chénais, B & Helal, AN 2016, 'Biomarkers assessment in the peacock blenny Salaria pavo exposed to cadmium' Environmental Science and Pollution Research, pp. 1-17. DOI: 10.1007/s11356-016-6754-6

Naïja, A, Marchand, J, Kestemont, P, Haouas, Z, Blust, R, Chénais, B & Helal, AN 2016, 'Mercury accumulation and its effects on molecular, physiological, and histopathological responses in the peacock blenny Salaria pavo' Environmental Science and Pollution Research, pp. 1-17. DOI: 10.1007/s11356-016-7401-y

Puiggalí-Jou, A, Pérez-Madrigal, MM, Del Valle, LJ, Armelin, E, Casas, MT, Michaux, C, Perpète, EA, Estrany, F & Alemán, C 2016, 'Confinement of a β-barrel protein in nanoperforated free-standing nanomembranes for ion transport' Nanoscale, vol 8, no. 38, pp. 16922-16935. DOI: 10.1039/c6nr04948f

Roland, K, Kestemont, P,  Dieu, M, Raes, M & Silvestre, F, 2016, 'Using a novel “Integrated Biomarker Proteomic” index to assess the effects of freshwater pollutants in European eel peripheral blood mononuclear cells' Journal of Proteomics, vol 137, pp. 83-96. DOI: 10.1016/j.jprot.2016.01.007

Schnitzler JG, Frédérich B, Dussenne M, Klaren PHM, Silvestre F, Das K. 2016. Triclosan exposure results in alterations of thyroid hormone status and retarded early development and metamorphosis in Cyprinodon variegatus. Aquatic Toxicology 181:1–10. DOI: 10.1016/j.aquatox.2016.10.019.

Voisin, AS, Fellous, A, Earley, RL & Silvestre, F 2016, 'Delayed impacts of developmental exposure to 17-α-ethinylestradiol in the self-fertilizing fish Kryptolebias marmoratus' Aquatic Toxicology, vol 180, pp. 247-257. DOI: 10.1016/j.aquatox.2016.10.003