Hueder Paulo Moisés de Oliveira

Environmental contaminants pose threats to exposed organisms and negatively impact the nervous, cardiovascular, immune, and reproductive systems. Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that are ubiquitous in the environment. Given that mixtures of environmental contaminants have the potential to exacerbate toxicity, we reviewed the current literature on pesticides, microplastics, or metal exposure in combination with PFAS on aquatic vertebrates and invertebrates. The objectives were to evaluate the toxicological effects of mixtures of the selected contaminants with PFAS on aquatic organisms to better understand biological responses in animals. Based on our review, data suggest that PFAS can modify the toxicity of co-occurring pollutants. For example, synergistic effects on toxicity include chlorpyrifos + perfluorohexanoic acid (PFHxA), which increased reactive oxygen species (ROS) and upregulated neurotoxicity-related genes in zebrafish, and perfluorooctanoic acid (PFOA) + atrazine, which increased the presence of malformations and oxidative stress. However, antagonistic interactions were also observed, for example, reduced herbicide toxicity in PFOA + 2,4-dichlorophenoxyacetic acid (2,4-D) mixtures. PFAS combined with microplastics often intensified oxidative stress and developmental or reproductive effects, though polyethylene microplastics attenuated perfluorooctane sulfonic acid (PFOS)-induced immunotoxicity in fish like seabass. Interactions with metals also varied, with copper and cadmium enhancing oxidative stress while mercury mixtures with PFAS showed antagonism, underscoring the complexity of mixture effects in real environments. A computational approach demonstrated that PFOS can engage in intermolecular interactions with pesticides, microplastic monomers, and metals, suggesting chemical-level effects that could modify toxicity or bioavailability. Future studies should focus on elucidating the mechanisms underlying these complex interactions, investigating effects at different trophic levels and in a broader range of species, and should consider environmentally relevant mixtures.

Environmental contaminants pose threats to various organisms and negatively impact the nervous, cardiovascular, immune, and reproductive systems. Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that are ubiquitous in the environment. Given that mixtures of environmental contaminants have the potential to exacerbate toxicity, we reviewed current literature on pesticides, microplastics, or metal exposure in combination with PFAS on vertebrates and invertebrates. The objectives were to evaluate the toxicological effects of mixtures of different pollutants (microplastics, pesticides and metal ions) with PFAS on aquatic organisms to better understand biological responses in animals. Based on our review, an increase in toxicity is observed in mixtures of pollutants, including enhanced oxidative stress, developmental abnormalities, impaired reproduction, metabolic disruption, altered gene expression, and changes in enzymatic activity; however, some antagonistic interactions were also reported, underscoring the complexity of mixture effects in real environments. A computational assessment demonstrates that PFOS can engage in intermolecular interactions with pesticides, microplastic monomers, and metals, suggesting chemical-level mechanisms that could modify toxicity or bioavailability. Future studies should focus on elucidating the mechanisms underlying these complex interactions, investigating effects at different trophic levels and in a broader range of species, including mammalian models, and considering chronic exposures and environmentally relevant mixtures.

BIOINSPIRED DESIGN OF DYES. The history of the discovery, use, and development of dyes is closely linked to the history of humanity itself. Among the first records of human civilization are cave paintings made from, e.g., fruits, plants, minerals, and insects. Over the centuries, using different techniques, colors have been given to all types of materials and products, from clothing to food. The chemicals responsible for colors are dyes – a vast collection of molecules of the most varied compositions, but which have in common the absorption of light within the visible window of the electromagnetic spectrum. This article aims not only to review the properties of some classes of natural dyes, their origins, and their applications but also to describe the various computational chemistry methods involved in designing new bio-inspired molecules.

The aim of this study was to evaluate the effect of SPP with either fetal bovine serum (FBS) or deionized water (DW) on the bond strength (μTBS) of a Universal adhesive to dentin, in both etch-and-rinse (ER) and self-etch (SE) modes. The kinematic viscosity (cSt) of FBS and DW was measured at 25 °C ± 0.1 ºC. Seventy-two sound human molars were sectioned and randomly divided into three groups according to the SPP conditions: (1) Control (0 cm H₂O), (2) SPP (15 cm H₂O) with FBS, (3) SPP (15 cm H₂O) with DW. Each group was subdivided (n = 10) based on the bonding modes: ER (37% phosphoric acid + ScothBond Universal Adhesive) or SE (ScothBond Universal Adhesive). Samples were then submitted to μTBS. Data were analyzed by Student’s t test, two-way ANOVA and Tukey tests (p < 0.05). The cSt results showed that DW (23.59 ± 0.39) had significantly higher values than FBS (22.33 ± 0.06). With regard to SPP, the control group (36.1 MPa) had significantly higher values of μTBS when compared to the SPP using FBS (31.06 MPa) and SPP with DW (26.55 MPa). According to ANOVA, the bonding modes and the interaction of simulated pulpal pressure (SPP) did not statistically influence the results (p < 0.05). The presence of SPP reduced the bond strength of Universal adhesive to dentin. DW during SPP had significantly reduced bonding values when compared to FBS. Bonding strategies were not affected by SPP when evaluated in a short period of time (24 h).