Do functional traits and biochemical biomarkers of the nematode Oncholaimus campylocercoides De Coninck and Schuurmans Stekhoven, 1933 affected by fluoranthene and polystyrene microplastics? Results from a microcosm bioassay and molecular modeling

The current experiment measured the multifaceted effects of polystyrene and fluoranthene, acting alone or in a mixture, on the meiobenthic nematode species Oncholaimus campylocercoides. This Oncholaimid was first experimentally selected from an entire nematode assemblage taken from the Jeddah coasts (Saudi Arabia). Several discernible changes were found in morphometry and functional traits after exposure to single and combined treatments. An increase in the activity of the biochemical biomarkers catalase and glutathione S-transferase was also observed following the exposure of males and gravid females of O. campylocercoides to 37.5 ng fluoranthene·g dry weight (DW) and 62.5 mg polystyrene·kg DW paralleled by a higher vulnerability of females. Moreover, the reproduction and feeding of this species were impaired, starting from 37.5 ng fluoranthene·g and 62.5 mg polystyrene·kg, respectively. These results have been confirmed by good binding affinities and molecular interactions of fluoranthene and polystyrene with both GLD-3 and SDP receptors.