Adult young as the fragile ontogenetic stage of the house crickets dietary exposed to GO nanoparticles - digestive enzymes perspective

Graphene oxide nanoparticles (GO) (have promising properties for, electronics, energy, medicine, water purification, agriculture and food production industry. However, their potentially hazardous effects are still not satisfactorily recognized, so they are often included in the group of contaminants of emerging concern. Therefore, the aim of this investigation was to assess the potentially harmful effects of orally administered GO on the digestive enzyme activities of the house crickets Acheta domesticus. The activity of digestive enzymes was measured using the API®ZYM test and the results were compared in relation to the insect age group (Larvae, Adult Young and Adult Mature) and previous selection towards longevity ('long living' vs 'wild' strains). General analysis, encompassing all digestive enzymes simultaneously, as well as an analysis performed for individual enzyme subgroups, revealed that both factors and their interactions significantly modified the activity of digestive enzymes of A. domesticus. The most pronounced effect was connected with the age factor. The study revealed that the Adult Young age group was the most sensitive; in this group, the activity of digestive enzymes was, in general, decreased in comparison with the control group, while the remaining group did not respond to GO with a similar intensity. In turn, the inter-strain comparisons demonstrated different response patterns to the GO. The control enzymatic activity of the insects from long living' strain was, in general, higher than in the 'wild strain'; however, it was significantly decreased in the GO-exposed groups, while in the 'wild' strain, the activity remained relatively homogenous. Additionally, the tendency was more pronounced in Adult Young than in the remaining age groups. The potential toxicity of GO requires further investigation, mainly with a focus on the composition and functioning of gut microbiotas.