RESUMO
Water contamination greatly impacts human health. The Metropolitan Area of the Valley of Mexico (MAVM) is one of the most densely inhabited and polluted places globally, with a significant problem being the rising water demand. The research aims to assess the impact of metals such as iron, aluminum, lead, cadmium, and total chromium, among others, in the water of the Madin Dam, a key reservoir in the area's water supply. The assessment concentrated on individuals who were in good health and had been exposed to these pollutants. It analyzed factors such as levels of oxidized proteins; changes in the function of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase); and their genetic expression, the occurrence of micronuclei, and the amount of DNA methylation. The findings were linked to the metals present in the MAVM drinking water, and the risk was evaluated. The research included four groups: two associated with the Madin Dam, consisting of persons living nearby or using water from the reservoir, and two acting as a control. The study highlighted a significant link between long-term exposure to pollutants in drinking water and elevated levels of oxidized proteins, increased micronuclei frequency, changes in antioxidant enzyme activity and gene expression, and a higher percentage of 5-methylcytosine. The risk assessment showed that people who use drinking water and/or consume fish from Madin Dam have a potential higher risk associated with metal contamination.
Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água , Humanos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Projetos Piloto , Medição de Risco , México , Abastecimento de Água , Exposição Ambiental/estatística & dados numéricos , Água Potável/química , Adulto , Masculino , Metais/análise , Metais/toxicidadeRESUMO
The rupture of Vale S.A. mining tailings dam in Brumadinho, Brazil, in January 2019 had significant environmental impacts on the Paraopeba River basin. Additionally, severe floods in early 2022 contributed to the transport of particles in the river. This study aimed to evaluate the cytotoxic and genotoxic potential of Paraopeba River water. Thus, the Allium cepa test system was applied, along with physicochemical analyses, flow cytometry, and metal concentration, comparing the results between the rainy and dry seasons three years after the dam rupture. The tests were conducted on water samples collected during three periods: January 2022, July 2022, and January 2023, at five points along the river and its tributaries. Allium cepa seeds were exposed to the collected water samples, as well as negative (water) and positive (trifluralin) controls. Cytotoxicity was evaluated using the mitotic index and flow cytometry, and genotoxicity by the chromosomal alterations index. The analysis of metals and physicochemical parameters revealed that most values complied with current regulations. However, there were exceptions, with ammonia levels exceeding the permitted limits at all points in the three collections. High levels of aluminum, iron and nitrite were found at most points, before and after the dam collapse, mainly during the rainy season. This indicates the impact of rainfall on water quality, which increases the transport of contaminating particles, probably resulting from human activities and the high concentration of nitrogen compounds released into the Paraopeba River. The results of the bioassay suggest a relatively low cytotoxic and genotoxic potential of the samples evaluated. However, this study highlights the continuous contamination of the river by unidentified anthropogenic factors, requiring continuous monitoring and analysis to track the evolution of water quality and its environmental effects.
Assuntos
Monitoramento Ambiental , Rios , Poluentes Químicos da Água , Brasil , Rios/química , Poluentes Químicos da Água/análise , Metais/análise , Cebolas/efeitos dos fármacos , Monitoramento Biológico , Mineração , Mutagênicos/análise , Mutagênicos/toxicidadeRESUMO
Bullfrog tadpoles were exposed (96 h) to water from two sites (the Ibiúna and the Itupararanga reservoir) on the Sorocaba River (São Paulo, Brazil). Metal concentrations (Ba, Cu, Mn, Sr and Zn) and metallothioneins (MTs) levels were determined in the gills (n = 27) and caudal muscle (n = 18). Metals increased in the gills of the animals exposed to the waters of the Sorocaba River in relation to the control and in relation to the animals exposed to the waters of the Ibiúna point. The levels of MT in gills were higher in animals exposed to the Itupararanga reservoir compared to the control. There was a strong correlation between metals and the presence of MT in gills, indicating that this organ can be used in environmental biomonitoring. The results demonstrate the need to protect the waters of the Sorocaba River, and especially the Itupararanga reservoir, through quality monitoring and reduction of anthropogenic pressure.
Assuntos
Monitoramento Biológico , Biomarcadores , Monitoramento Ambiental , Brânquias , Larva , Metalotioneína , Rana catesbeiana , Rios , Poluentes Químicos da Água , Animais , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo , Brasil , Rios/química , Monitoramento Ambiental/métodos , Metalotioneína/metabolismo , Biomarcadores/metabolismo , Biomarcadores/análise , Brânquias/metabolismo , Brânquias/química , Metais/análiseRESUMO
The association of bacteria resistant to potentially toxic metals (PTMs) with plants to remove, transfer, or stabilize these elements from the soil is an appropriate tool for phytoremediation processes in metal-contaminated environments. The objective of this study was to evaluate the potential of Rhizobium sp. LBMP-C04 for phytoremediation processes and plant growth promotion in metal-contaminated soils. Functional annotation allowed us to predict a variety of genes related to PTMs resistance and plant growth promotion in the bacterial genome. Resistance genes are mainly associated with DNA repair, and the import or export of metals in bacterial cells to maintain cell homeostasis. Genes that promote plant growth are related to mechanisms of osmotic stress tolerance, phosphate solubilization, nitrogen metabolism, biological nitrogen fixation, biofilm formation, heat shock responses, indole-3-acetic acid (IAA) biosynthesis, tryptophan, and organic acids metabolism. Biochemical tests indicated that Rhizobium sp. LBMP-C04 can solubilize calcium phosphate and produce siderophores and IAA in vitro in the presence of the PTMs Cd2+,Cu2+,Cr3+,Cr6+, Zn2+, and Ni2+. Results indicate the possibility of using Rhizobium sp. LBMP-C04 as a potentially efficient bacterium in phytoremediation processesin environments contaminated by PTMs and simultaneously promote plant growth.
Assuntos
Biodegradação Ambiental , Ácidos Indolacéticos , Desenvolvimento Vegetal , Rhizobium , Microbiologia do Solo , Poluentes do Solo , Rhizobium/genética , Rhizobium/metabolismo , Poluentes do Solo/metabolismo , Poluentes do Solo/toxicidade , Ácidos Indolacéticos/metabolismo , Metais/metabolismo , Metais Pesados/toxicidade , Metais Pesados/metabolismo , Sideróforos/metabolismo , Fosfatos/metabolismo , Genoma BacterianoRESUMO
Pregnancy increases the demand for essential metal ions to support fetal development, making the maternal metal ion status a critical determinant of perinatal outcomes. This prospective cohort study examined changes in metal ion levels across the three trimesters, evaluated the influence of preexisting metabolic conditions on the metal ion status, and assessed the associations between maternal metal ion levels and perinatal outcomes in 206 pregnant women from the Biochemical and Epigenetic Origin of Overweight and Obesity (OBESO) cohort receiving care at the Instituto Nacional de Perinatología in Mexico City from 2017 to 2020. Six essential metal ions (iron, zinc, copper, calcium, magnesium, and phosphorus) were measured in blood samples using inductively coupled plasma optic emission spectrometry. Significant variations in the metal ion levels were observed across the trimesters, with notable decreases in iron and magnesium and increases in copper as pregnancies progressed. Maternal hypothyroidism was associated with significantly low levels of zinc and magnesium during pregnancy. Regression analyses revealed robust associations between maternal metal ion levels and perinatal outcomes. For instance, declining magnesium levels as pregnancies progressed were positively associated with gestational diabetes (OR: 2.92, p = 0.04; OR: 2.72, p = 0.03). The maternal metal ion status significantly influences perinatal outcomes.
Assuntos
Resultado da Gravidez , Humanos , Feminino , Gravidez , México/epidemiologia , Adulto , Metais/sangue , Estudos Prospectivos , Complicações na Gravidez/sangue , Complicações na Gravidez/epidemiologia , Magnésio/sangue , Zinco/sangue , Cobre/sangue , Ferro/sangue , Cálcio/sangue , Adulto JovemRESUMO
Transition metals function as structural and catalytic cofactors for a large diversity of proteins and enzymes that collectively comprise the metalloproteome. Metallostasis considers all cellular processes, notably metal sensing, metalloproteome remodeling, and trafficking (or allocation) of metals that collectively ensure the functional integrity and adaptability of the metalloproteome. Bacteria employ both protein and RNA-based mechanisms that sense intracellular transition metal bioavailability and orchestrate systems-level outputs that maintain metallostasis. In this review, we contextualize metallostasis by briefly discussing the metalloproteome and specialized roles that metals play in biology. We then offer a comprehensive perspective on the diversity of metalloregulatory proteins and metal-sensing riboswitches, defining general principles within each sensor superfamily that capture how specificity is encoded in the sequence, and how selectivity can be leveraged in downstream synthetic biology and biotechnology applications. This is followed by a discussion of recent work that highlights selected metalloregulatory outputs, including metalloproteome remodeling and metal allocation by metallochaperones to both client proteins and compartments. We close by briefly discussing places where more work is needed to fill in gaps in our understanding of metallostasis.
Assuntos
Bactérias , Proteínas de Bactérias , Metaloproteínas , Metais , Bactérias/metabolismo , Metais/metabolismo , Metais/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Metaloproteínas/metabolismo , Metaloproteínas/química , Homeostase , RiboswitchRESUMO
Contamination of water bodies is a significant global issue that results from the deliberate release of pollutants into the environment, especially from mining and metal processing industries. The main pollutants generated by these industries are metallic wastes, particularly metals, which can cause adverse effects on the environment and human health. Therefore, it is crucial to develop effective and sustainable approaches to prevent their discharge into the environment. Biofiltration is a technique used to remediate contaminated fluids using biological processes. Microorganisms and agro-industrial wastes have been used successfully as biosorbents. Hence, this review emphasizes the innovative use of agro-industrial waste reinforced with microbial biomass as bioadsorbents, highlighting their dual capacity for metal removal through various bioremediation mechanisms. The mechanisms at play in these biocomposite materials, which offer enhanced sustainability, are also analyzed. This study contributes to the advancement of knowledge by suggesting new strategies for integrating reinforced materials in biosorption processes, thus providing a novel perspective on the potential of lignocellulosic-based systems to improve decontamination efforts. On the other hand, it shows some studies where the optimization and scaling-up of biosorption processes are reported. Additionally, the implementation of multisystem approaches, leveraging multiple bioremediation techniques simultaneously, can further enhance the efficiency and sustainability of metal removal in contaminated environments.
Assuntos
Bactérias , Biodegradação Ambiental , Biomassa , Descontaminação , Resíduos Industriais , Metais , Bactérias/metabolismo , Metais/química , Metais/metabolismo , Descontaminação/métodos , Agricultura/métodos , Poluentes Químicos da Água/metabolismoRESUMO
Cigarette butts are classified as plastic waste due to their composition of cellulose acetate fibers and are commonly found in beach sand. Their persistence in the environment, low biodegradability, and potential to interact with metals and metalloids during the aging process make them a significant subject of interest for research on coastal marine ecosystems. The aim of this study is to investigate the presence of metals such as hexavalent chromium Cr (VI), cadmium (Cd), and the metalloid arsenic (As) in cigarette butts (CBs), cigarette butt fibers (CBFs), and sand on a tourist beach in Cartagena, Colombia. The goal is to establish a baseline for potential contamination on the beach due to these elements. The methodology includes collecting samples of CBs, CBFs, and sand from different beach usage zones (active, rest, and service) and conducting standardized laboratory tests using atomic absorption spectroscopy for As and Cd and the standard colorimetric method for Cr (VI). The main findings indicate that arsenic levels reached 7.69, 5.75, and 3.47 mg As/kg in the sand, CBs, and CBFs, respectively. Cadmium and hexavalent chromium were found to be below the detection limit for the applied methodology. Additionally, mercury was detected at a concentration of 0.37 mg Hg/L in CBFs in the active zone in October.
Assuntos
Monitoramento Ambiental , Monitoramento Ambiental/métodos , Colômbia , Poluentes Químicos da Água/análise , Cromo/análise , Cádmio/análise , Metaloides/análise , Praias , Metais/análise , Produtos do Tabaco/análiseRESUMO
Metals and metalloids are persistent environmental pollutants with the potential for bioaccumulation, posing significant health risks, including genotoxicity. These contaminants are prevalent in industrial and agricultural runoff. This study utilizes Trachemys dorbigni, an aquatic reptile, as a bioindicator to assess environmental contamination by metals and metalloids in both rural and urban settings in Pelotas, Rio Grande do Sul, Brazil. We captured specimens using pit-type traps with barriers (fyke nets), dividing them into two groups: 15 from a rural area and 15 from an urban area. Each animal underwent physical evaluations, and biometric data (weight, total carapace length and width) were recorded to calculate body condition indices. Biological samples were collected via manual restraint, with blood samples drawn from the supraoccipital venous sinus and linear carapace fragments obtained through manual scraping. Water samples from each location were also analyzed. Using atomic absorption spectrophotometry, concentrations of Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn were measured in the water, carapace fragments, and blood samples. Cellular damage was assessed through flow cytometry and microscopy, examining erythrocyte disruption, reactive oxygen species, membrane fluidity, DNA fragmentation and micronucleus formation. Urban area samples showed concentrations of As, Cd, Cu, Fe, Hg and Ni exceeding national standards set by the Conselho Nacional do Meio Ambiente (CONAMA), with rural areas also showing elevated levels of As, Cd, Hg and Ni. Biometric analysis revealed that rural reptiles had significantly higher weight and carapace dimensions, whereas urban tortoises displayed a higher body condition index and significantly elevated blood levels of Al, Cr, Ni, Pb and Zn. The urban tortoises also exhibited higher concentrations of all tested metal(loid) in carapace samples (p < 0.05) and more pronounced cellular damage (p < 0.05), highlighting severe bioaccumulation and associated deleterious effects. Elevated reactive oxygen species levels were noted in rural specimens. This study underscores the impact of water degradation and metal(loid) pollution in urban environments on T. dorbigni, suggesting that carapace tissue analysis can serve as a chronic exposure indicator to these harmful contaminants.
Assuntos
Monitoramento Ambiental , Metais , Poluentes Químicos da Água , Animais , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Brasil , Lagartos , Metais Pesados/análiseRESUMO
The use of residues from petroleum and crop industries is a feasible and sustainable alternative approach for the production of xanthan gum (XG). This study aimed to evaluate the biosynthesis of XG and the resulting final product obtained using Xanthomonas axonopodis pv. manihotis 1182 in a medium containing produced water (PW) and cassava processing residues. The combined use of PW and cassava crop residues was beneficial for XG production, achieving a product yield of 6.80 g L-1. The micrographs of recovered XG revealed the presence of elongated fiber-like microstructures rather than large agglomerates. The X-ray diffraction profiles of recovered xanthan comprised well-defined peaks rather than an amorphous halo. The thermogravimetry profiles revealed the presence of approximately 60 % of remaining solids in recovered xanthan, in contrast to 30 % in the commercial sample. All the samples demonstrated a pseudoplastic behavior; however, the consistency indices of the recovered samples were approximately 50-times lower than those of commercial XG. The emulsification indices of the recovered XG were > 50 % and comparable to those of commercial xanthan. In this study, for the first time, we obtained a complex XG-metal structure possessing a high emulsification capacity and low viscosity.
Assuntos
Manihot , Polissacarídeos Bacterianos , Água , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/biossíntese , Manihot/química , Água/química , Metais/química , Viscosidade , Difração de Raios X , Xanthomonas axonopodisRESUMO
Settleable atmospheric particulate matter (SePM), from steelmaking processes, contains a complex mixture of metals, metalloids, and metallic nanoparticles. The SePM is released airborne and disperses in water, representing a significant threat to aquatic life, particularly fish. This study investigated the effects of a sublethal and environmentally relevant concentration of SePM (1 g·L-1) for 96 h in the gill, liver, kidney, and white muscle of Nile tilapia (Oreochromis niloticus), employing exposure and effect biomarkers to test causality between metal accumulation and biochemical responses. The gills and liver showed the highest bioaccumulation of metals and integrated response index value, indicating susceptibility to metal accumulation. However, the gills produce a protective mucus layer that may mitigate metal toxicity. The kidneys and muscle tissue also showed bioaccumulation of metals, although to a lesser extent. The liver and kidneys experienced oxidative stress, characterized by reduced metallothionein and glutathione levels, as well as damage to lipids, proteins, and DNA. The accumulation of less-studied metals, particularly Rare Earth Elements (REEs), compromised the integrity of biomolecules in these tissues. In conclusion, the complex dynamics of metal bioaccumulation in Nile tilapia exposed to SePM reveal varied tissue responses and primary effects like oxidative damage. They also highlight the need for further research and regulation of other metals and their potential impacts on aquatic ecosystems and human health.
Assuntos
Bioacumulação , Ciclídeos , Metalotioneína , Estresse Oxidativo , Poluentes Químicos da Água , Animais , Metalotioneína/metabolismo , Ciclídeos/metabolismo , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade , Poeira , Metais/metabolismo , Brânquias/metabolismo , Fígado/metabolismo , Rim/metabolismoRESUMO
Sharks, are highly vulnerable to fishing pressures, a key factor in their global population decline. Chemical pollution, however, especially metal and metalloid contamination, poses significant additional risks. Of around 520 shark species, about 170 are threatened, including the Sphyrna genus (hammerheads). This review examines contamination in these sharks and its ecological and human health implications. A scientometric review indicates limited research, mainly on juveniles and only mercury contamination, with scarce data on other metals, life stages, and consumption thresholds. The findings also indicate a certain amount of Colonial Science concerning ecotoxicological Sphyrna spp. assessments. The expected link between ecotoxicological risks and Sphyrna spp. threat status remains inconclusive due to insufficient data. Notably, larger hammerhead species do not always exhibit higher contamination levels, suggesting that local environmental factors may influence contamination more than biological characteristics. More research is required to understand how environmental pressures impact shark vulnerability and inform conservation strategies.
Assuntos
Ecotoxicologia , Monitoramento Ambiental , Metaloides , Metais , Tubarões , Poluentes Químicos da Água , Animais , Metaloides/análise , Poluentes Químicos da Água/análise , Metais/análise , Metais/toxicidadeRESUMO
OBJECTIVES: To investigate the influence of combining levels of metal artifact reduction (MAR) tool with different filters and slice-thickness in the detection of mandibular canals perforated by implants on CBCT scans and to objectively assess the impact of the aforementioned combinations. MATERIALS AND METHODS: Implants were placed above (8 implants) and inside (10 implants) mandibular canals of dried-mandibles. CBCT scans were obtained with the Eagle 3D unit (85 kVp, 8 mA, 5 × 5 cm FOV, 130 µm voxel size, and off/medium/high MAR levels). Examiners evaluated the scans under each MAR level and across different conditions: no filter, Sharpen 1×, Sharpen 2×; 0 mm, 1 mm, and 2 mm slice-thickness. The gray values on axial reconstructions were assessed. Area under the receiver operating characteristic curve (AUC), sensitivity, specificity, mean and standard deviation (SD) for gray values were calculated and compared by multi-way Analysis of Variance. RESULTS: Overall, the AUC and sensitivity decreased with high-level MAR (p < 0.0001), regardless other variables tested. Enabling MAR tool decreased mean gray values (p < 0.01) and increasing MAR levels reduced the SD values on scans with Sharpen 2× (p < 0.012). CONCLUSIONS: High-level MAR impairs the visualization of mandibular canals perforated by implants. Moreover, enabling MAR tool decreases the mean gray values. CLINICAL RELEVANCE: MAR tool, filters, and slice thickness influence the image quality of CBCT scans. Therefore, it is important to evaluate the impact of these parameters on the diagnosis of mandibular canals perforated by implants.
Assuntos
Artefatos , Tomografia Computadorizada de Feixe Cônico , Implantes Dentários , Mandíbula , Metais , Tomografia Computadorizada de Feixe Cônico/métodos , Humanos , Mandíbula/diagnóstico por imagem , Mandíbula/cirurgia , Sensibilidade e Especificidade , Técnicas In Vitro , Imageamento Tridimensional/métodosRESUMO
In urban centers, sewage treatment plants (STPs) serve as foraging and shelter areas for bats; however, they are sources of persistent pollutants that affect the health of these animals. This study aimed to investigate the impact of pollutants from an STP on the health of different species of neotropical bats from different guilds using non-invasive biomarkers. A conservation unit, the Silvania National Forest (SNF), was used as a reference area for comparison purposes. Blood, buccal mucosa, and fur samples were obtained for comet assay, micronucleus test, leukocyte profile, and metal concentration analysis in fur. Our results demonstrated that bats collected at the STP show a higher frequency of genotoxic damage, nuclear abnormalities, and an inflammatory response linked to infection than bats from the SNF. Regarding guilds, frugivores and nectarivores showed more pronounced responses to damage, but insectivores bats also showed relevant responses. While STPs are considered a source of pollutants, other urban sources of contamination likely contributed to these results. Still we encourage further studies using other non-invasive biomarkers, detection analysis of different pollutants in biological matrices, and the use of other wildlife species inserted in urban centers.
Assuntos
Biomarcadores , Quirópteros , Monitoramento Ambiental , Metais , Testes para Micronúcleos , Animais , Metais/análise , Metais/toxicidade , Monitoramento Ambiental/métodos , Ensaio Cometa , Cidades , Poluentes Ambientais/análise , Poluentes Ambientais/toxicidade , Dano ao DNA , Mucosa Bucal , Brasil , Exposição Ambiental/análise , EsgotosRESUMO
Volcanic eruptions can release large amounts of tephra, lava, and gases, drawing attention due to their magnitude, energy, and impact on life and the environment. Among the most documented and sometimes dramatic effects of volcanic ashes are those linked to the input of diverse elements in the environment, which are released as a consequence of ash weathering. Laboratory studies have been conducted to investigate and predict the environmental input of chemical elements from volcanic ashes. This research paper describes the optimization of batch leaching tests used to investigate the release of ions from ashes collected in the Andes Cordillera after the eruption of the Puyehue volcano in 2011. Chemometric multivariate strategies were employed to evaluate the influence of variables affecting the leaching of volcanic ash. The effects of the main variables, namely contact time, the acidity of the leaching agent, the solid/liquid ratio, the particle size, and the stirring speed, were studied in leaching tests. To determine the optimal conditions for selected metal determinations, we employ Darringer's desirability function, which allows for the simultaneous optimization of the selected responses (element concentrations during the leaching process). Multielemental analysis (Na, Mg, Al, Si, P, Cl, K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Cd, Hg, Tl, and Pb) was quantified by ICP-MS (inductively coupled plasma-mass spectrometry) following adequate dilution of test leaching. These results established the optimal experimental conditions for leaching volcanic ash. The most significant variables were the solid/liquid ratio and the stirring speed, resulting in two groups of elements with an adequate global desirability function (D) value.
Assuntos
Erupções Vulcânicas , Monitoramento Ambiental/métodos , Metais/análise , Tamanho da PartículaRESUMO
Chemical pollutants include the harmful effects of various substances on soils, water bodies, and biodiversity. Amphibians are one of the most endangered groups of vertebrates and are impacted by chemical pollutants in various ways due to their complex life cycles. Since trace pollutant concentrations vary across environments, different frog ecomorphs (classified by their microhabitat use) may have different exposures. We aimed to determine the association between frog ecomorphs and the occurrence of histopathological hepatic lesions (HHLs) as an indicator of contaminant exposure. We focused on small forest streams near a large urban region in Brazil, heavily polluted in the 1980s. We examined 104 frog specimens from various families. All specimens exhibited HHLs, with melanomacrophages being the most common (n = 99). Arboreal frogs exhibited more vascular congestion, while terrestrial frogs showed structural hepatic damage. Higher cobalt levels were linked to increased liver necrosis in arboreal frogs and structural issues in both arboreal and terrestrial frogs. Cadmium was associated with hepatitis in terrestrial frogs. Although metal levels had no significant effects on rheophilic frogs, the prevalence of hepatitis and necrosis indicated complex exposure pathways. Iron and aluminum were linked to fewer lesions in rheophilic frogs, suggesting resilience. The high prevalence of HHLs signals an ongoing issue, with variations among ecomorphs suggesting differential exposure to pollutants and posing a complex challenge for community conservation.
Assuntos
Anuros , Monitoramento Ambiental , Fígado , Animais , Brasil , Fígado/efeitos dos fármacos , Metais/toxicidade , Poluentes Químicos da Água/toxicidadeRESUMO
CONTEXT: Phosphodiester bonds, which form the backbone of DNA, are highly stable in the absence of catalysts. This stability is crucial for maintaining the integrity of genetic information. However, when exposed to catalytic agents, these bonds become susceptible to cleavage. In this study, we investigated the role of different metal dications (Ca2âº, Mg2âº, Zn2âº, Mn2âº, and Cu2âº) in promoting the hydrolysis of phosphodiester bonds. A minimal DNA model was constructed using two pyrimidine nucleobases (cytosine and thymine), two deoxyribose units, one phosphate group, and one metallic dication coordinated by six water molecules. The results highlight that Cu2⺠is the most efficient in lowering the energy barrier for bond cleavage, with an energy barrier of 183 kJ/mol, compared to higher barriers for metals like Zn2⺠(202 kJ/mol), Mn2⺠(202 kJ/mol), Mg2⺠(210 kJ/mol), and Ca2⺠(223 kJ/mol). Understanding the interaction between these metal ions and phosphodiester bonds offers insight into DNA stability and organic data storage systems. METHODS: DFT calculations were employed using Gaussian 16 software, applying the B3LYP hybrid functional with def2-SVP basis sets and GD3BJ dispersion corrections. Full geometry optimizations were performed for the initial and transition states, followed by identifying energy barriers associated with phosphodiester bond cleavage. The optimization criteria included maximum force, root-mean-square force, displacement, and energy convergence thresholds.
Assuntos
DNA , Hidrólise , DNA/química , Modelos Moleculares , Metais/química , TermodinâmicaRESUMO
AIM: To evaluate the influence of different levels of metal artifact reduction (MAR) tool and milliamperage (mA) on the diagnosis of fracture extension in endodontically treated teeth using cone beam CT (CBCT). MATERIALS AND METHODS: Ten maxillary premolars were endodontically treated and positioned in the empty sockets of a human maxilla covered with wax. CBCT acquisitions were performed using the Eagle Edge device (Dabi Atlante, Brazil) adjusted to 120 kVp, FOV of 4 × 6 cm, exposure time of 24 s and voxel size of 0.2 mm in 8 different conditions with different MAR (1, 2 and 3) and mA (3.2 and 6.3) levels. Crown-root fractures were simulated in the universal testing machine, and CBCT images were acquired again. Five radiologists evaluated the presence and extension of fractures with a 5-point scale. Statistical analysis was performed by analysis of variance, Tukey and Kappa test (α = 0.05). RESULTS: Although different mA levels did not significantly (p > 0.05) affect the diagnosis values for fracture presence and extension, when evaluated the different levels of MAR, AUC and sensitivity showed significantly higher values (p < 0.05) for MAR 0 using 6.3 mA and kappa agreement showed significantly higher values (p < 0.05) for MAR 0 and 2 using 6.3 mA. CONCLUSIONS: Although mA levels do not have a diagnostic effect when isolating the MAR level; in 6.3 mA, MAR 0 and 2 can positively influence the diagnosis of fracture extension in endodontically treated teeth using CBCT. CLINICAL RELEVANCE: The isolate evaluation of dental fracture presence can overlook diagnostics error of its extension.
Assuntos
Artefatos , Dente Pré-Molar , Tomografia Computadorizada de Feixe Cônico , Fraturas dos Dentes , Dente não Vital , Humanos , Fraturas dos Dentes/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Dente não Vital/diagnóstico por imagem , Dente Pré-Molar/diagnóstico por imagem , Dente Pré-Molar/lesões , Técnicas In Vitro , Metais , Maxila/diagnóstico por imagem , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: Metal and metalloid exposures (hereafter "metals") are associated with adverse health outcomes, including type 2 diabetes; however, previous studies were largely cross-sectional or underpowered. Furthermore, underserved racial and ethnic groups are underrepresented in environmental health research despite having higher rates of type 2 diabetes and a greater risk of metal exposures. Consequently, we evaluated continuous glycemic traits in relation to baseline urinary toxic metal, essential metal, and metal mixtures in a cohort of Mexican American adults. RESEARCH DESIGN AND METHODS: A total of 510 participants were selected based upon self-reported diabetes status and followed over 3 years. Urinary metals were assessed at baseline. Linear mixed-effects models were used to estimate per-month changes in hemoglobin A1c, fasting plasma glucose, and postload glucose in relation to urinary metal levels. Multiple statistical approaches were used to assess the associations between glycemic traits and metal mixtures. RESULTS: After adjustment, higher urinary levels of arsenic, selenium, copper, molybdenum, nickel, and tin were associated with faster increases in measures of glycemia. The toxic metal mixture composed of arsenic, lead, cadmium, nickel, and tin was associated with faster increases in postload glucose. Using postload glucose criteria, highest versus lowest arsenic was predicted to accelerate conversion of normoglycemia to prediabetes and diabetes by 23 and 65 months, respectively. CONCLUSIONS: In this underrepresented, high-risk Mexican American population, exposure to toxic metals and alterations in essential metal homeostasis were associated with faster increases in glycemia over time that may accelerate type 2 diabetes development.
Assuntos
Glicemia , Americanos Mexicanos , Humanos , Americanos Mexicanos/estatística & dados numéricos , Feminino , Masculino , Texas/epidemiologia , Pessoa de Meia-Idade , Adulto , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/urina , Diabetes Mellitus Tipo 2/etnologia , Diabetes Mellitus Tipo 2/epidemiologia , Metais/urina , Arsênio/urina , Hemoglobinas Glicadas/metabolismo , Hemoglobinas Glicadas/análise , Estudos LongitudinaisRESUMO
Environmental reference conditions (RC) and historical trends are crucial for assessing the degree of freshwater impact and formulating restoration measures. This is particularly relevant for freshwater systems used as potable water sources. Using sediments from the Carlos Maggiolo reservoir (Minas, Uruguay), located in a watershed with a mining history, this study aimed to (1) establish metal (As, Cr, Cu, Ni, Pb, and Zn) RC using a predicted interval (PI) chemometric technique; (2) evaluate metal enrichment and toxicity over time and space; and (3) assess environmental changes examining geochemical proxies. Surface sediments from 29 stations were used to establish RC and a core from the dam area was sampled to infer past conditions. The sediments were submitted to partial digestion and analyzed by inductively coupled plasma optical emission spectrometry- ICP-OES. Enrichment factor (EF) calculated using both PI and bottom core values did not show significant differences over time. Over space and time, most metals primarily originated from natural sources (EF < 2). The PI in mg/kg was Cr: 23.74-37.32; Cu: 25.75-48.99; Ni: 16.29-25.55; Pb: 7.63-13.75; and Zn: 94.34-174.80. A stratigraphically constrained cluster analysis corroborated by a permutational multivariate analysis of variance categorized the reservoir into two zones: Zone I, before reservoir operation to ~ 1996, and Zone II from ~ 1997 to 2017. The average concentrations of the main metals of toxicological interest in zones I and II, respectively, were as follows: Cr 37.60 ± 1.59, 34.54 ± 1.49 mg/kg; Cu 49.76 ± 2.84, 44.55 ± 2.70 mg/kg; Ni 24.11 ± 0.67, 22.53 ± 1.22 mg/kg; Pb 12.40 ± 0.63, 13.52 ± 0.82 mg/kg; Zn 99.25 ± 3.12, 93.86 ± 4.42 mg/kg; Mn 1160.56 ± 68.88, 1441.61 ± 83.55 mg/kg; and P 1243.21 ± 271.56, 1128.42 ± 183.10 mg/kg. According to a principal component analysis, the period preceding reservoir operation until ~ 1985 was linked to mining activities and application of Cu2SO4, and the period from 1985s to 2000 was influenced by C and P concentrations due to increasing agricultural and afforestation activities in the watershed that consume P fertilizers. The most recent period, from 2000 to ~ 2017, was characterized by an increase in sedimentation rates mainly associated with erosion, particularly in the agricultural areas. This subsequent soil loss in the watershed could compromise the reservoir's useful life. This study contributes to a better understanding of metal geochemistry in subtropical reservoirs and aids in formulating effective recovery and restoration measures.