Environmental toxicology and pharmacology最新文献

This study aimed to assess the risk of pesticides on bee pollinators and propose strategies to conserve entomophilous angiosperm species in the Ndop wetlands. Results showed that the applied pesticide doses were often excessive, increasing the exposure toxicity ratios (ETR). Among the pesticides, insecticides posed the highest risk to bee pollinators, with Emamectin benzoate (ETR=591.4) presenting the highest risk, followed by imidacloprid (ETR=517.5), fipronil (ETR=496.4), chlorpyrifos (ETR=240.7), and cypermethrin (ETR=131). Lambda-cyhalothrin (ETR=50.53) posed a possible risk. The study found that imidacloprid, fipronil, and chlorpyrifos posed definite risks through dietary exposure, while Emamectin benzoate, fipronil, and cypermethrin posed risks through direct contact. Approximately 46.03% of angiosperms are anemophilous while 53% are entomophilous with bee pollinators facilitating the pollination of nearly 90% of the entomophilous species. To mitigate pesticide risks and for conservation purposes, farmers should refrain from applying pesticides during blooming and peak pollinator activity times, particularly midday.

The most recent dam rupture in Brazil released tons of mining tailings into the upper course of the Paraopeba River, affecting this river in an unprecedented way. The present study aimed to evaluate the influence of heavy metals on Prochilodus costatus, an important commercial species in Brazil, four years after the dam colapse. To this end, biomarkers of heavy metals, oxidative stress, and environmental stress were analyzed, and histological analyses of target organs were performed. The results demonstrated critical contamination of fish from the Paraopeba River. Increased expression of Metallothioneins - MTs, Heat Shock Protein - HSP70, and inducible nitric oxide synthase - iNOS, as well as greater rates of histological changes in the liver, spleen, and gonads, were observed in P. costatus. These findings demonstrate that, despite past contamination, the metals present in mining tailings have significantly increased the contamination of the Paraopeba River basin.

We analyzed gene expression in THP-1 cells exposed to metal-based nanomaterials (NMs) [TiO₂ (NM-100), ZnO (NM-110), SiO₂ (NM-200), Ag (NM-300 K)]. A functional enrichment analysis of the significant differentially expressed genes (DEGs) identified the key modulated biological processes and pathways. DEGs were used to construct protein-protein interaction networks. NM-110 and NM-300 K induced changes in the expression of genes involved in oxidative and genotoxic stress, immune response, alterations of cell cycle, detoxification of metal ions and regulation of redox-sensitive pathways. Both NMs shared a number of highly connected protein nodes (hubs) including CXCL8, ATF3, HMOX1, and IL1B. NM-200 induced limited transcriptional changes, mostly related to the immune response; however, several hubs (CXCL8, ATF3) were identical with NM-110 and NM-300 K. No effects of NM-100 were observed. Overall, soluble nanomaterials NM-110 and NM-300 K exerted a wide variety of toxic effects, while insoluble NM-200 induced immunotoxicity; NM-100 caused no detectable changes on the gene expression level.

Chlorpyrifos, widely used for pest control, is known to have various harmful effects, although its toxic effects in macrophages and the mechanisms underlying its toxicity remain unclear. The present study investigated the toxic effects of chlorypyrifos in a macrophage cell line. Here, we found that chlorpyrifos induced cytotoxicity and genotoxicity in RAW264.7 macrophages. Moreover, chlorpyrifos induced intracellular ROS production, subsequently leading to lipid peroxidation. Chlorpyrifos reduced the activation of antioxidative enzymes including superoxide dismutase, catalase, and glutathione peroxidase. Chlorpyrifos upregulated HO-1 expression and activated the Keap1-Nrf2 pathway, as indicated by enhanced Nrf2 phosphorylation and Keap1 degradation. Chlorpyrifos exerted effects on the following in a dose-dependent manner: cytotoxicity, genotoxicity, lipid peroxidation, intracellular ROS production, antioxidative enzyme activity reduction, HO-1 expression, Nrf2 phosphorylation, and Keap1 degradation. Notably, N-acetyl-L-cysteine successfully inhibited chlorpyrifos-induced intracellular ROS generation, cytotoxicity, and genotoxicity. Thus, chlorpyrifos may induce cytotoxicity and genotoxicity by promoting intracellular ROS production and suppressing the antioxidative defense system activation in macrophages.