Multigenerational exposure to silver ions and silver nanoparticles reveals heightened sensitivity and epigenetic memory in Caenorhabditis elegans.
The effects from multigenerational exposures to engineered nanoparticles (ENPs) in their pristine and transformed states are currently unknown despite such exposures being an increasingly common scenario in natural environments. Here, we examine how exposure over 10 generations affects the sensitivity of the nematode Caenorhabditis elegans to pristine and sulfidized Ag ENPs and AgNO3 We also include populations that were initially exposed over six generations but kept unexposed for subsequent four generations to allow recovery from exposure. Toxicity of the different silver forms decreased in the order AgNO3, Ag ENPs and Ag2S ENPs. Continuous exposure to Ag ENPs and AgNO3 caused pronounced sensitization (approx. 10-fold) in the F2 generation, which was sustained until F10. This sensitization was less pronounced for Ag2S ENP exposures, indicating different toxicity mechanisms. Subtle changes in size and lifespan were also measured. In the recovery populations, the sensitivity to Ag ENPs and AgNO3 resulting from the initial multigenerational exposure persisted. Their response sensitivity for all endpoints was most closely related to the last ancestral exposed generation (F5), rather than unexposed controls. The mechanisms of transgenerational transfer of sensitivity are probably organized through the epigenome, and we encourage others to investigate such effects as a priority for mechanistic toxicology.
Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxon OX10 8BB, UK Department of Materials, Oxford University, Begbroke Science Park, Begbroke Hill, Yarnton, Oxford OX5 1PF, UK.
Carolin L
0000-0003-1578-5114
CL
Schultz
Department of Plant and Soil Sciences, University of Kentucky, 1100 S. Limestone St., Lexington, KY 40546, USA.
Anye
A
Wamucho
Department of Plant and Soil Sciences, University of Kentucky, 1100 S. Limestone St., Lexington, KY 40546, USA.
Olga V
OV
Tsyusko
Department of Plant and Soil Sciences, University of Kentucky, 1100 S. Limestone St., Lexington, KY 40546, USA.
Jason M
JM
Unrine
Department of Materials, Oxford University, Begbroke Science Park, Begbroke Hill, Yarnton, Oxford OX5 1PF, UK.
Alison
A
Crossley
Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxon OX10 8BB, UK.
Claus
C
Svendsen
Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxon OX10 8BB, UK dasp@ceh.ac.uk.
David J
DJ
Spurgeon
D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000235:genetics*; D044127:Epigenesis, Genetic; D007477:Ions; D053768:Metal Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
D007477:Ions; D012834:Silver
epigenetics; multigenerational exposure; nanotoxicology; silver; silver sulfide; transgenerational effects