Ecotoxic, genotoxic, and cytotoxic potential of leachate obtained from chromated copper arsenate-treated wood ashes

Preservative treatments increase the durability of wood, and one of the alternative treatments involves the use of chromated copper arsenate (CCA). Due to the toxicity of CCA, the disposal of CCA-treated wood residues is problematic, and burning is considered to provide a solution. The ecotoxicological potential of ash can be high when these components are toxic and mutagenic. The aim of this study was to evaluate the toxicity and genotoxicity of bottom ash leachates originating from CCA-treated wood burning. Physical-chemical analysis of the leachates revealed that in treated wood ashes leachate (CCA-TWBAL), the contents of arsenic and chromium were 59.45 mg.L^-1 and 54.28 mg.L^-1, respectively. In untreated wood ashes leachate (UWBAL), these contents were 0.70 mg.L^-1 and 0.30 mg.L^-1, respectively. CCA-TWBAL caused significant toxicity in Lactuca sativa, Allium cepa, and microcrustacean Artemia spp. (LC50 = 12.12 mg.mL^-1). Comet assay analyses using NIH3T3 cells revealed that concentrations ranging from 1.0 and 2.5 mg.mL^-1 increase the damage frequency (DF) and damage index (DI). According to MTT assay results, CCA-TWBAL at concentrations as low as 1 mg.mL^-1 caused a significant decrease in cellular viability. Hemolysis assay analyses suggest that the arsenic and chromium leachate contents are important for the ecotoxic, cytotoxic, and genotoxic effects of CCA-TWBAL.

Peptide-Integrated Superparamagnetic Nanoparticles for the Identification of Epitopes from SARS-CoV-2 Spike and Nucleocapsid Proteins

The COVID-19 pandemic, caused by the fast transmission and spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently considered a serious health problem, requiring an effective strategy to contain SARS-CoV-2 dissemination. For this purpose, epitopes of the SARS-CoV-2 spike (S) and sucleocapsid (N) proteins were identified by bioinformatics tools, and peptides that mimic these epitopes were chemically synthesized and then conjugated to superparamagnetic nanoparticles (SPMNPs). Three peptides from S protein and three from N protein were used as antigens in a conventional enzyme-linked immunosorbent assay (ELISA) against serum samples from COVID-19-positive patients, or from healthy donors, collected before the pandemic. Three peptides were effective as antigens in conventional peptide-based ELISA, achieving 100% sensitivity and specificity, with high accuracy. The best-performing peptides, p2pS, p1pN, and p3pN, were associated with superparamagnetic nanoparticles (SPMNPs) and were used to perform nanomagnetic peptide-based ELISA. The p2pS-SPMNP conjugate presented 100% sensitivity and specificity and excellent accuracy (area under the curve (AUC) = 1.0). However, p1pN and p3pN peptides, when conjugated to SPMNPs, did not preserve the capacity to differentiate positive sera from negative sera in all tested samples, yet both presented sensitivity and specificity above 80% and high accuracy, AUC > 0.9. We obtained three peptides as advantageous antigens for serodiagnosis. These peptides, especially p2pS, showed promising results in a nanomagnetic peptide-based ELISA and may be suitable as a precoated antigen for commercial purposes, which would accelerate the diagnosis process.

Genotoxicity evaluation induced by Tityus serrulatus scorpion venom in mice

Tityus serrulatus is the scorpion associated with the most severe cases of scorpion envenoming in Brazil. However, there are no studies reporting the genotoxic effects of this venom in natural or experimental envenomations. It is well known that DNA-damage responses are providing opportunities for improving disease detection and management. In this study was evaluating the genotoxicity of the T. serrulatus venom in different organs (hippocampus, cortex, striatum, blood, heart, lung, liver and kidney) and periods in mice experimentally envenomed. ELISA and the Comet assays were used to quantification of venoms antigens and DNA damage, respectively. Forty-eight Swiss mice were divided into five groups and 0.5 DL₅₀ of T. serrulatus venom (0.90 mg/kg) was administered intraperitoneally in each animal. Euthanasia was performed by cervical dislocation in the period of 0h (control group) 1h, 2h, 6h and 12h, where it the tissues were removed. The results showed high DNA damage in all structures analyzed, suggesting that T. serrulatus venom presented genotoxic activity or some secondary effect generated by venom injection. In the ELISA test, toxic circulant antigens were verified in practically all organs at the time intervals analyzed. Therefore, the distribution of the venom changes from organ to organ. We conclude that scorpion envenoming affects DNA in all organs analyzed even when the venom concentration is lower or no detectable, DNA damage persists.