Slime molds response to carbon nanotubes exposure: from internalization to behavior

Abstract

Carbon nanotubes (CNTs) offer attractive opportunities due to their physical, electrical, mechanical, optical, and thermal properties. They are used in a wide range of applications and are found in numerous consumer products. On the downside, their increasing presence in the environment poses potential threats to living organisms and ecosystems. The aim of this study was to evaluate the toxicity of double-walled carbon nanotubes (DWCNTs) on a new model system: the acellular slime mold Physarum polycephalum. Despite its ecological significance, its simplicity of organization, and its behavioral complexity, exposure of such organisms to nanoparticles has been poorly investigated. Slime molds were exposed to DWCNTs using three routes of exposure (topical, food, environment). We first demonstrated that DWCNTs were rapidly internalized by slime molds especially when DWCNTs were mixed with the food or spread out in the environment. Secondly, we showed that a 6-week exposure to DWCNTs did not lead to bioaccumulation nor did it lead to persistence in the slime molds when they entered a resting stage. Thirdly, we revealed that 2 days following exposure, DWCNTs were almost entirely excreted from the slime molds. Lastly, we uncovered that DWCNTs exposure altered the migration speed, the pseudopods formation, and the expansion rate of the slime molds. Our results extend our current knowledge of CNTs cytotoxicity and introduce P. polycephalum as an ideal organism for nanotoxicology.

Keywords:

• Slime mold
• carbon nanotubes
• ecotoxicology
• behavior

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

M.T. was financially supported by a grant from the ‘Agence Nationale de la recherche’ (reference no. ANR-17-CE02-0019-01-SMARTCELL, Principal investigator: A.D.) and the University of Toulouse and the Région Occitanie/Université Paul Sabatier (reference no. ALDOCT001112, Principal investigator: A.D.). A.D. and E.F. were supported by the MITI ‘Mission pour les initiatives transverses et interdisciplinaires’ funded by the CNRS. (reference: NTCELL – Principal investigator: A.D.).