Vijver Martina G.

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Vijver
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Martina G.
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  • Article
    Partitioning the impact of environmental drivers and species interactions in dynamic aquatic communities
    (Ecological Society of America, 2019-11-12) Musters, C. J. M. ; Ieromina, Oleksandra ; Barmentlo, S. Henrik ; Hunting, Ellard R. ; Schrama, Maarten ; Cieraad, Ellen ; Vijver, Martina G. ; van Bodegom, Peter M.
    Temperate aquatic communities are highly diverse and seasonally variable, due to internal biotic processes and environmental drivers, including human‐induced stressors. The impact of drivers on species abundance is supposed to differ fundamentally depending on whether populations are experiencing limitations, which may shift over the season. However, an integrated understanding of how drivers structure communities seasonally is currently lacking. In order to partition the effect of drivers, we used random forests to quantify interactions between all taxa and environmental factors using macrofaunal data from 18 agricultural ditches sampled over two years. We found that, over the agricultural season, taxon abundance became increasingly better predicted by the abundances of co‐occurring taxa and nutrients compared to other abiotic factors, including pesticides. Our approach provides fundamental insights in community dynamics and highlights the need to consider changes in species interactions to understand the effects of anthropogenic stressors.
  • Preprint
    Nanoparticles induce dermal and intestinal innate immune system responses in zebrafish embryos
    ( 2018-03) Brun, Nadja R. ; Koch, Bjørn E. V. ; Varela, Mónica ; Peijnenburg, Willie J. G. M. ; Spaink, Herman P. ; Vijver, Martina G.
    Major molecular mechanisms that underpin the toxicity of nanoparticles (NPs) are the formation of reactive oxygen species and the induction of inflammation. The latter is frequently observed in vitro and in mammalian organisms, yet in aquatic organisms, such NP-induced inflammatory responses remain largely unexplored. Zebrafish offer a wide range of molecular tools to investigate immune responses in an aquatic organism, and were therefore used here to describe how copper (Cu) NPs (25 nm; 1 mg L-1) and soluble Cu as well as polystyrene (PS) NPs (25 nm; 10 mg L1-) induce innate immune responses, focussing on the skin cells and the intestine as likely organs of interaction. mRNA expression of the immune responsive genes interleukin 1 beta (il1β) and immunoresponsive gene 1-like (irg1l) of CuNP exposed embryos was observed to be 46 weaker in the intestinal tissue compared to the rest of the body, indicating a strong outer epithelium response. Specifically, NPs were observed to accumulate in the cavities of lateral neuromasts in the skin, which coincided with an increased local expression of il1β. Exposure to CuNPs triggered the strongest transcriptional changes in pro-inflammatory-related genes and was also observed to increase migration of neutrophils in the tail, indicating a NP-specific inflammatory response. This is the first in vivo evidence for waterborne NP exposure triggering alterations of immune system regulating genes in the skin and intestines of zebrafish embryos. The observed molecular responses have the potential to be linked to adverse effects at higher levels of biological organization and hence might offer screening purposes in nanotoxicology or building blocks for adverse outcome pathways.
  • Article
    Microbially-mediated indirect effects of silver nanoparticles on aquatic invertebrates
    (Springer, 2018-09-14) Zhai, Yujia ; Brun, Nadja R. ; Bundschuh, Mirco ; Schrama, Maarten ; Hin, Eline ; Vijver, Martina G. ; Hunting, Ellard R.
    Complex natural systems are affected by multiple anthropogenic stressors, and therefore indirect effects within food webs are increasingly investigated. In this context, dead organic matter (OM) or detritus provides a food source sustaining detrital food webs that recycle the retained energy through microbial decomposition and invertebrate consumption. In aquatic environments, poorly water-soluble contaminants, including nanoparticles (NPs), quickly adsorb onto OM potentially modifying OM-associated microbial communities. Since invertebrates often depend on microbial conditioning to enhance OM quality, adverse effects on OM-associated microbial communities could potentially affect invertebrate performances. Therefore, this study assessed the effect of environmentally relevant concentrations of the model emerging contaminant, silver nanoparticles (AgNPs), on OM-associated microorganisms and subsequent indirect effects on growth of the invertebrate Asellus aquaticus. At low concentrations (0.8 ug/L), AgNPs inhibited activity and altered metabolic diversity of the OM-associated microbial community. This was observed to coincide with a negative effect on the growth of A. aquaticus due to antimicrobial properties, as a decreased growth was observed when offered AgNP-contaminated OM. When A. aquaticus were offered sterile OM in the absence of AgNPs, invertebrate growth was observed to be strongly retarded, illustrating the importance of microorganisms in the diet of this aquatic invertebrate. This outcome thus hints that environmentally relevant concentrations of AgNPs can indirectly affect the growth of aquatic invertebrates by affecting OM-associated microbial communities, and hence that microorganisms are an essential link in understanding bottom-up directed effects of chemical stressors in food webs.
  • Article
    Polystyrene nanoplastics disrupt glucose metabolism and cortisol levels with a possible link to behavioural changes in larval zebrafish
    (Nature Research, 2019-10-18) Brun, Nadja R. ; van Hage, Patrick ; Hunting, Ellard R. ; Haramis, Anna-Pavlina G. ; Vink, Suzanne C. ; Vijver, Martina G. ; Schaaf, Marcel J. M. ; Tudorache, Christian
    Plastic nanoparticles originating from weathering plastic waste are emerging contaminants in aquatic environments, with unknown modes of action in aquatic organisms. Recent studies suggest that internalised nanoplastics may disrupt processes related to energy metabolism. Such disruption can be crucial for organisms during development and may ultimately lead to changes in behaviour. Here, we investigated the link between polystyrene nanoplastic (PSNP)-induced signalling events and behavioural changes. Larval zebrafish exhibited PSNP accumulation in the pancreas, which coincided with a decreased glucose level. By using hyperglycemic and glucocorticoid receptor (Gr) mutant larvae, we demonstrate that the PSNP-induced disruption in glucose homoeostasis coincided with increased cortisol secretion and hyperactivity in challenge phases. Our work sheds new light on a potential mechanism underlying nanoplastics toxicity in fish, suggesting that the adverse effect of PSNPs are at least in part mediated by Gr activation in response to disrupted glucose homeostasis, ultimately leading to aberrant locomotor activity.