First report on the toxicity of SARS-CoV-2, alone and in combination with polyethylene microplastics in neotropical fish

The COVID-19 pandemic has caused unprecedented negative impacts in the modern era, including economic, social, and public health losses. On the other hand, the potential effects that the input of SARS-CoV-2 in the aquatic environment from sewage may represent on non-target organisms are not well known. In addition, it is not yet known whether the association of SARS-CoV-2 with other pollutants, such as microplastics (MPs), may further impact the aquatic biota. Thus, we aimed to evaluate the possible ecotoxicological effects of exposure of male adults Poecilia reticulata, for 15 days, to inactivated SARS-CoV-2 (0.742 pg/L; isolated SARS.CoV2/SP02.2020.HIAE.Br) and polyethylene MP (PE MPs) (7.1 × 104 particles/L), alone and in combination, from multiple biomarkers. Our data suggest that exposure to SARS-CoV-2 induced behavioral changes (in the open field test), nephrotoxic effect (inferred by the increase in creatinine), hepatotoxic effect (inferred by the increase in bilirubin production), imbalance in the homeostasis of Fe, Ca, and Mg, as well as an anticholinesterase effect in the animals [marked by the reduction of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity]. On the other hand, exposure to PE MPs induced a genotoxic effect (assessed by the comet assay), as well as an increase in enzyme activity alpha-amylase, alkaline phosphatase, and carboxylesterases. However, we did not show synergistic, antagonistic, or additive effects caused by the combined exposure of P. reticulata to SARS-CoV-2 and PE MPs. Principal component analysis (PCA) and values from the "Integrated Biomarker Response" index indicate that exposure to SARS-CoV-2 was determinant for a more prominent effect in the evaluated animals. Therefore, our study sheds light on the ecotoxicity of the new coronavirus in non-target organisms and ratifies the need for more attention to the impacts of COVID-19 on aquatic biota.The authors are grateful to the Goiano Federal Institute (IF Goiano/Brazil), National Council for Scientific and Technological Development (CNPq/Brazil), Foundation for Research Support of the State of Goiás (FAPEG, Brazil), and Foundation for Research Support (FUNAPE, Brazil) for the financial support needed to conduct this research. Nós agradecemos a todos os estudantes do Laboratório de Toxicologia Aplicada ao Meio Ambiente (IF Goiano/Brazil) que contribuíram na coleta de dados ao longo do experimento. Malafaia G. holds a productivity scholarship from CNPq (Proc. No. 308854/2021-7).Peer reviewe

Polyethylene microplastics are ingested and induce biochemical changes in Culex quinquefasciatus (Diptera: Culicidae) freshwater insect larvae

Although microplastics’ (MPs) toxicity has been reported in several aquatic and terrestrial organisms, the knowledge about how these pollutants can affect insects at the early developmental stage remains incipient. Thus, the aim of this study was to use Culex quinquefasciatus larvae as a model system to test the hypothesis that, besides accumulating in animals, polyethylene microplastics (PE MPs) lead to biochemical changes predictive of nutritional impacts, as well as induce oxidative stress, redox state imbalance, and neurotoxicity in them. Our results have indicated that short exposure to PE MPs (5 days) at the environmental concentration of 4.24 x 106 particles m-3 induced changes suggesting damage to energy metabolism such as reduced total proteins, total soluble carbohydrates, and triglycerides levels. In addition, increased thiobarbituric acid reactive species, in association with reduced total glutathione and DPPH radical scavenging activity (%) have suggested an imbalance between oxide-reducing agents and antioxidant defense system, induced by pollutant. On the other hand, increased acetylcholinesterase activity has suggested the neurotoxic effect of PE MPs. Finally, PE MPs have accumulated in the larvae, and it may have been a triggering factor for the observed changes. Thus, our study has confirmed the potential of C. quinquefasciatus larvae to act as vector of MPs in different ecosystems and helped improving the knowledge about how PE MPs can affect their development and lead to losses in different ecological functions of this species

Shedding light on the toxicity of SARS-CoV-2-derived peptide in non-target COVID-19 organisms: A study involving inbred and outbred mice

Despite advances in research on the vaccine and therapeutic strategies of COVID-19, little attention has been paid to the possible (eco)toxicological impacts of the dispersion of SARS-CoV-2 particles in natural environments. Thus, in this study, we aimed to evaluate the behavioral and biochemical consequences of the short exposure of outbred and inbred mice (male Swiss and C57Bl/6 J mice, respectively) to PSPD-2002 (peptide fragments of the Spike protein of SARS-CoV-2) synthesized in the laboratory. Our data demonstrated that after 24 h of intraperitoneal administration of PSPD-2002 (at 580 μg/kg) the animals did not present alterations in their locomotor, anxiolytic-like, or anxiety-like behavior (in the open field test), nor antidepressant-like or depressive behavior in the forced swimming test. However, the C57Bl/6 J mice exposed to PSPD-2002 showed memory deficit in the novel object recognition task, which was associated with higher production of thiobarbituric acid reactive substances, as well as the increased suppression of acetylcholinesterase brain activity, compared to Swiss mice also exposed to peptide fragments. In Swiss mice the reduction in the activity of superoxide dismutase and catalase in the brain was not associated with increased oxidative stress biomarkers (hydrogen peroxide), suggesting that other antioxidant mechanisms may have been activated by exposure to PSPD-2002 to maintain the animals' brain redox homeostasis. Finally, the results of all biomarkers evaluated were applied into the "Integrated Biomarker Response Index" (IBRv2) and the principal component analysis (PCA), and greater sensitivity of C57Bl/6 J mice to PSPD-2002 was revealed. Therefore, our study provides pioneering evidence of mammalian exposure-induced toxicity (non-target SARS-CoV-2 infection) to PSPD-2002, as well as "sheds light" on the influence of genetic profile on susceptibility/resistance to the effects of viral peptide fragments.The authors are grateful to the Goiano Federal Institute and the National Council for Scientific and Technological Development (CNPq/Brazil) for the financial support needed to conduct this research (Proc. No. 23219.000137.2022-28 and 403065/2021-6, respectively). Malafaia G. holds a productivity scholarship from CNPq (Proc. No. 307743/2018-7).Peer reviewe