RESUMO
Straightforward manufacturing pathways toward large-scale, uniformly layered composites may enable the next generation of materials with advanced optical, thermal, and mechanical properties. Reaction-diffusion systems are attractive candidates to this aim, but while layered composites theoretically could spontaneously arise from reaction-diffusion, in practice randomly oriented patches separated by defects form, yielding nonuniformly patterned materials. A propagating reaction front can prevent such nonuniform patterning, as is the case for Liesegang processes, in which diffusion drives a reaction front to produce layered precipitation patterns. However, while diffusion is crucial to control patterning, it slows down transport of reactants to the front and results in a steady increase of the band spacing as the front advances. Here, we circumvent these diffusive limitations by embedding the Liesegang process in mechanically responsive hydrogels. The coupling between a moving reaction front and hydrogel contraction induces the formation of a self-regulated transport channel that ballistically carries reactants toward the area where patterning occurs. This ensures rapid and uniform patterning. Specifically, large-scale ([Formula: see text]5-cm) uniform banding patterns are produced with tunable band distance (d = 60 to 160 µm) of silver dichromate crystals inside responsive gelatin-alginate hydrogels. The generality and applicability of our mechanoreaction-diffusion strategy are demonstrated by forming patterns of precipitates in significantly smaller microscopic banding patterns (d = 10 to 30 µm) that act as self-organized diffraction gratings. By circumventing the inherent limitations of diffusion, our strategy unlocks the potential of reaction-diffusion processes for the manufacturing of uniformly layered materials.
Assuntos
Hidrogéis , Manufaturas , Alginatos/química , Cromatos/química , Difusão , Gelatina/química , Hidrogéis/química , Prata/químicaRESUMO
A deficiency of the essential macronutrient sulfur leads to stunted plant growth and yield loss; however, an association with a symbiotic fungus can greatly improve nutrient uptake by the host plant. Here, we identified and functionally characterized a high-affinity sulfate transporter from the endophytic fungus Serendipita indica. SiSulT fulfills all the criteria expected of a functional sulfate transporter responding to sulfur limitation: SiSulT expression was induced when S. indica was grown under low-sulfate conditions, and heterologous expression of SiSulT complemented a yeast mutant lacking sulfate transport. We generated a knockdown strain of SiSulT by RNA interference to investigate the consequences of the partial loss of this transporter for the fungus and the host plant (maize, Zea mays) during colonization. Wild-type (WT) S. indica, but not the knockdown strain (kd-SiSulT), largely compensated for low-sulfate availability and supported plant growth. Colonization by WT S. indica also allowed maize roots to allocate precious resources away from sulfate assimilation under low-sulfur conditions, as evidenced by the reduction in expression of most sulfate assimilation genes. Our study illustrates the utility of the endophyte S. indica in sulfur nutrition research and offers potential avenues for agronomically sound amelioration of plant growth in low-sulfate environments.
Assuntos
Basidiomycota/fisiologia , Transportadores de Sulfato/metabolismo , Enxofre/metabolismo , Zea mays/crescimento & desenvolvimento , Zea mays/microbiologia , Cultura Axênica , Basidiomycota/metabolismo , Transporte Biológico , Cromatos/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Mutação , Micologia/métodos , Filogenia , Interferência de RNA , Transportadores de Sulfato/genética , Sulfatos/metabolismo , Leveduras/genética , Zea mays/metabolismoRESUMO
Hexavalent chromium [Cr(VI)] is considered a major environmental health concern and lung carcinogen. However, the exact mechanism by which Cr(VI) causes lung cancer in humans remains unclear. Since several reports have demonstrated a role for inflammation in Cr(VI) toxicity, the present study aimed to apply transcriptomics to examine the global mRNA expression in human lung fibroblasts after acute (24 h) or prolonged (72 and 120 h) exposure to 0.1, 0.2 and 0.3 µg/cm2 zinc chromate, with a particular emphasis on inflammatory pathways. The results showed Cr(VI) affected the expression of multiple genes and these effects varied according to Cr(VI) concentration and exposure time. Bioinformatic analysis of RNA-Seq data based on the Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and MetaCore databases revealed multiple inflammatory pathways were affected by Cr(VI) treatment. qRT-PCR data corroborated RNA-Seq findings. This study showed for the first time that Cr(VI) regulates key inflammatory pathways in human lung fibroblasts, providing novel insights into the mechanisms by which Cr(VI) causes lung cancer.
Assuntos
Cromo , Fibroblastos , Pulmão , Transcriptoma , Humanos , Cromo/toxicidade , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibroblastos/patologia , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/patologia , Transcriptoma/efeitos dos fármacos , Perfilação da Expressão Gênica/métodos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/metabolismo , Inflamação/induzido quimicamente , Inflamação/genética , Inflamação/metabolismo , Cromatos/toxicidade , Compostos de Zinco/farmacologia , Compostos de Zinco/toxicidade , Linhagem Celular , Carcinogênese/efeitos dos fármacos , Carcinogênese/induzido quimicamente , Carcinogênese/genética , Transdução de Sinais/efeitos dos fármacosRESUMO
The role of pH in sequestration of Cr(VI) by zerovalent magnesium (ZVMg) was characterized by global fitting of a kinetic model to time-series data from unbuffered batch experiments with varying initial pH values. At initial pH values ranging from 2.0 to 6.8, ZVMg (0.5 g/L) completely reduced Cr(VI) (18.1 µM) within 24 h, during which time pH rapidly increased to a plateau value of â¼10. Time-series correlation analysis of the pH and aqueous Cr(VI), Cr(III), and Mg(II) concentration data suggested that these conditions are controlled by combinations of reactions (involving Mg0 oxidative dissolution and Cr(VI) sequestration) that evolve over the time course of each experiment. Since this is also likely to occur during any engineering applications of ZVMg for remediation, we developed a kinetic model for dynamic pH changes coupled with ZVMg corrosion processes. Using this model, the synchronous changes in Cr(VI) and Mg(II) concentrations were fully predicted based on the Langmuir-Hinshelwood kinetics and transition-state theory, respectively. The reactivity of ZVMg was different in two pH regimes that were pH-dependent at pH < 4 and pH-independent at the higher pH. This contrasting pH effect could be ascribed to the shift of the primary oxidant of ZVMg from H+ to H2O at the lower and higher pH regimes, respectively.
Assuntos
Cromatos , Poluentes Químicos da Água , Cromatos/química , Magnésio , Ferro/química , Poluentes Químicos da Água/análise , Cromo/análise , Cromo/química , Cinética , Concentração de Íons de Hidrogênio , AdsorçãoRESUMO
Exposure to hexavalent chromium damages genetic materials like DNA and chromosomes, further elevating cancer risk, yet research rarely focuses on related immunological mechanisms, which play an important role in the occurrence and development of cancer. We investigated the association between blood chromium (Cr) levels and genetic damage biomarkers as well as the immune regulatory mechanism involved, such as costimulatory molecules, in 120 workers exposed to chromates. Higher blood Cr levels were linearly correlated with higher genetic damage, reflected by urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and blood micronucleus frequency (MNF). Exploratory factor analysis revealed that both positive and negative immune regulation patterns were positively associated with blood Cr. Specifically, higher levels of programmed cell death protein 1 (PD-1; mediated proportion: 4.12%), programmed cell death ligand 1 (PD-L1; 5.22%), lymphocyte activation gene 3 (LAG-3; 2.11%), and their constitutive positive immune regulation pattern (5.86%) indirectly positively influenced the relationship between blood Cr and urinary 8-OHdG. NOD-like receptor family pyrin domain containing 3 (NLRP3) positively affected the association between blood Cr levels and inflammatory immunity. This study, using machine learning, investigated immune regulation and its potential role in chromate-induced genetic damage, providing insights into complex relationships and emphasizing the need for further research.
Assuntos
Cromatos , Aprendizado de Máquina , Humanos , Estudos Transversais , Poluentes Ambientais , Masculino , Dano ao DNA , Adulto , Feminino , Pessoa de Meia-Idade , BiomarcadoresRESUMO
Ferrihydrite is an effective adsorbent of chromate and arsenate. In order to gain insight into the application of ferrihydrite in water treatment, macroporous alginate/ferrihydrite beads, synthesized using two different methods (internal and encapsulation processes), were used in this work. The properties of the ferrihydrite were assessed using various techniques, including X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) theory, and zetametry. The results showed that the specific surface area of the ferrihydrite was 242 m2/g, and the PZC was pH8. The kinetic and isotherm adsorption properties of the ferrihydrite were evaluated in this study. The results indicate that the pseudo second-order and Freundlich models accurately describe the kinetic and isotherm adsorption properties of chromates and arsenates. For chromate removal, ferrihydrite exhibited a relatively high adsorption capacity (40.7 mgCr/g) compared to other adsorbents. However, the arsenate adsorption capacity of MFHB-SI (140.8 mgAs/g) was shown to be the most optimal. The internal synthesis process was suitable for arsenate retention due to the resulting arsenate precipitation. The competitive adsorption analyses indicated that the presence of chromate does not limit the adsorption of arsenate. However, the presence of arsenate almost completely inhibits the adsorption of chromate when the arsenate concentration is above 50 mg/L, due to the precipitation reaction of arsenate.
Assuntos
Alginatos , Arseniatos , Cromatos , Compostos Férricos , Poluentes Químicos da Água , Arseniatos/química , Adsorção , Cromatos/química , Compostos Férricos/química , Alginatos/química , Poluentes Químicos da Água/química , Ácido Glucurônico/química , Cinética , Ácidos Hexurônicos/química , Purificação da Água/métodosRESUMO
Massive waste aluminum scraps produced from the spent aluminum products have high electron capacity and can be recycled as an attractive alternative to materials based on zero-valent iron (Fe0) for the removal of oxidative contaminants from wastewater. This study thus proposed an approach to fabricate micron-sized sulfidated zero-valent iron-aluminum particles (S-Al0@Fe0) with high reactivity, electron selectivity and capacity using recycled waste aluminum scraps. S-Al0@Fe0 with a three-layer structure contained zero-valent aluminum (Al0) core, Fe0 middle layer and iron sulfide (FeS) shell. The rates of chromate (Cr(VI)) removal by S-Al0@Fe0 at pH 5.0â9.0 were 1.6â5.9 times greater than that by sulfidated zero-valent iron (S-Fe0). The Cr(VI) removal capacity of S-Al0@Fe0 was 8.2-, 11.3- and 46.9-fold greater than those of S-Fe0, zero-valent iron-aluminum (Al0-Fe0) and Fe0, respectively. The chemical cost of S-Al0@Fe0 for the equivalent Cr(VI) removal was 78.5% lower than that of S-Fe0. Negligible release of soluble aluminum during the Cr(VI) removal was observed. The significant enhancement in the reactivity and capacity of S-Al0@Fe0 was partially ascribed to the higher reactivity and electron density of the Al0 core than Fe0. More importantly, S-Al0@Fe0 served as an electric cell to harness the persistent and selective electron transfer from the Al0-Fe0 core to Cr(VI) at the surface via coupling Fe0-Fe2+-Fe3+ redox cycles, resulting in a higher electron utilization efficiency. Therefore, S-Al0@Fe0 fabricated using recycled waste aluminum scraps can be a cost-effective and environmentally-friendly alternative to S-Fe0 for the enhanced removal of oxidative contaminants in industrial wastewater.
Assuntos
Cromatos , Poluentes Químicos da Água , Ferro/química , Águas Residuárias , Alumínio , Poluentes Químicos da Água/química , Cromo/químicaRESUMO
Hexavalent chromium and its compounds are prevalent pollutants, especially in the work environment, pose a significant risk for multisystem toxicity and cancers. While it is known that chromium accumulation in the liver can cause damage, the dose-response relationship between blood chromium (Cr) and liver injury, as well as the possible potential toxic mechanisms involved, remains poorly understood. To address this, we conducted a follow-up study of 590 visits from 305 participants to investigate the associations of blood Cr with biomarkers for liver injury, including serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), and direct bilirubin (DBIL), and to evaluate the mediating effects of systemic inflammation. Platelet (PLT) and the platelet-to-lymphocyte ratio (PLR) were utilized as biomarkers of systemic inflammation. In the linear mixed-effects analyses, each 1-unit increase in blood Cr level was associated with estimated effect percentage increases of 0.82% (0.11%, 1.53%) in TBIL, 1.67% (0.06%, 3.28%) in DBIL, 0.73% (0.04%, 1.43%) in ALT and 2.08% (0.29%, 3.87%) in AST, respectively. Furthermore, PLT mediated 10.04%, 11.35%, and 10.77% increases in TBIL, DBIL, and ALT levels induced by chromate, respectively. In addition, PLR mediated 8.26% and 15.58% of the association between blood Cr and TBIL or ALT. These findings shed light on the mechanisms underlying blood Cr-induced liver injury, which is partly due to worsening systemic inflammation.
Assuntos
Cromatos , Cromo , Inflamação , Humanos , Cromo/toxicidade , Cromo/sangue , Inflamação/sangue , Masculino , Cromatos/toxicidade , Cromatos/sangue , Adulto , Feminino , Pessoa de Meia-Idade , Biomarcadores/sangue , Exposição Ocupacional/efeitos adversos , Alanina Transaminase/sangue , Doença Hepática Induzida por Substâncias e Drogas/sangue , Aspartato Aminotransferases/sangue , Poluentes Ambientais/sangue , Poluentes Ambientais/toxicidadeRESUMO
Bioreduction of Cr(VI) to Cr(III) is a promising technology for removing Cr(VI), but Cr(VI) reduction alone cannot support microbial growth. This study investigated the reduction of Cr(VI) in the presence of three electron acceptors that typically coexist with Cr(VI): NO3-, SO42-, and Fe(III). All three systems could reduce Cr(VI) to Cr(III), but the fate of Cr, its impacts on reduction of the other acceptors, and its impact on the microbial community differed. Although Cr(VI) was continuously removed in the NO3--reduction systems, batch tests showed that denitrification was inhibited primarily through impeding nitrite reduction. The SO42- and Fe(III) reduction systems reduced Cr(VI) using a combination of biotic and abiotic processes. Across all three systems, the abundance of genera capable of reducing Cr(VI) increased following the introduction of Cr(VI). Conversely, the abundance of genera that cannot reduce or resist Cr(VI) decreased, leading to restructuring of the microbial community. Furthermore, the abundance of sulfide oxidizers and Fe(II) oxidizers substantially increased after the introduction of chromate. This study provides fundamental knowledge about how Cr(VI) bioreduction interacts with bioreductions of three other co-contaminating electron acceptors.
Assuntos
Cromatos , Compostos Férricos , Cromatos/metabolismo , Oxirredução , Elétrons , Cromo/metabolismoRESUMO
Turmeric adulterated with lead chromate pigment has been previously identified as a primary source of lead exposure in Bangladesh. This study assesses the impact of a multi-faceted intervention between 2017 and 2021 to reduce lead-tainted turmeric in Bangladesh. The intervention involved: i) disseminating findings from scientific studies via news media that identified turmeric as a source of lead poisoning, ii) educating consumers and businesspeople about the risks of lead chromate in turmeric via public notices and face-to-face meetings, and iii) collaborating with the Bangladesh Food Safety Authority to utilize a rapid lead detection technology to enforce policy disallowing turmeric adulteration. Before and after the intervention, evidence of lead chromate turmeric adulteration was assessed at the nation's largest turmeric wholesale market and at turmeric polishing mills across the country. Blood lead levels of workers at two mills were also assessed. Forty-seven interviews were conducted with consumers, businesspeople, and government officials to assess changes in supply, demand, and regulatory capacity. The proportion of market turmeric samples containing detectable lead decreased from 47% pre-intervention in 2019 to 0% in 2021 (n = 631, p < 0.0001). The proportion of mills with direct evidence of lead chromate adulteration (pigment on-site) decreased from 30% pre-intervention in 2017 to 0% in 2021 (n = 33, p < 0.0001). Blood lead levels dropped a median of 30% (IQR: 21-43%), while the 90th percentile dropped 49% from 18.2 µg/dL to 9.2 µg/dL 16 months after the intervention (n = 15, p = 0.033). Media attention, credible information, rapid lead detection tools and swift government action to enforce penalties all contributed to the intervention's success. Subsequent efforts should evaluate if this is an example of an effective intervention that can be replicated to reduce lead chromate adulteration of spices globally.
Assuntos
Cromatos , Chumbo , Humanos , Chumbo/análise , Curcuma , Bangladesh , Inocuidade dos AlimentosRESUMO
Low-cost adsorbents derived from agricultural by-products incorporated magnetic nanoparticles (NPs) are promising for wastewater treatment. They are always preferred due to their great performance and easy separation. This study reports cobalt superparamagnetic (CoFe2O4) nanoparticles (NPs) incorporated with triethanolamine (TEA) based surfactants from cashew nut shell liquid, namely TEA-CoFe2O4, for the removal of chromium (VI) ions from aqueous solutions. To have detailed characteristics of the morphology and structural properties, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM) were employed. The fabricated TEA-CoFe2O4 particles exhibit soft and superparamagnetic properties, which make the nanoparticles easily recycled by using a magnet. Chromate adsorption on the TEA-CoFe2O4 nanomaterials reached an optimal efficiency of 84.3% at pH = 3 with the initial adsorbent dose of 10 g/L and chromium (VI) concentration of 40 mg/L. The TEA-CoFe2O4 nanoparticles can maintain the effective adsorption of chromium (VI) ion (by 29% of efficiency loss) and retain the magnetic separation using a magnet up to three cycles of the regeneration, which promise a high potential of this low-cost adsorbent for long-term treatment of heavy metal ions from polluted waters.
Assuntos
Nanopartículas de Magnetita , Poluentes Químicos da Água , Cromatos , Espectroscopia de Infravermelho com Transformada de Fourier , Nanopartículas de Magnetita/química , Adsorção , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio , CinéticaRESUMO
A Gram-positive, aerobic, rod-shaped non-motile, non-sporulating bacterium, designated CSA2T, was isolated from chromium-containing soils collected from a chemical plant. The 16S rRNA gene sequence of strain CSA2T showed the highest homology with Leucobacter chromiireducens subsp. solipictus (97.85%), Leucobacter chromiireducens subsp. chromiireducens (97.85%). The digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI) and the amino acid identity (AAI) values among strains CSA2T and the selected Leucobacter species were 20.6-23.4% (dDDH), 72.67-78.03% (ANI) and 66.39-76.16% (AAI), falling below the recommended thresholds for species delimitation. The principal fatty acids were anteiso-C15:0, iso-C16:0 and anteiso-C17:0. The polar lipids were phosphatidylglycerol, diphosphatidylglycerol and an unknown glycolipid. The major menaquinones detected were MK-10 and MK-11. The cell-wall amino acids included 2,4-diaminobutyric acid, threonine, glutamic acid, alanine and glycine. Based on molecular feature, phenotypic and chemotaxonomic, strain CSA2T was considered to be a novel species of the genus Leucobacter., and the name Leucobacter edaphi sp. nov. is proposed. The type strain is CSA2T (= JCM 34360T = CGMCC 1.18747T).
Assuntos
Actinobacteria , Actinomycetales , Cromatos , Cromo , RNA Ribossômico 16S/genética , Técnicas de Tipagem Bacteriana , Ácidos Graxos/análise , Aminoácidos , DNA , Filogenia , DNA Bacteriano/genética , DNA Bacteriano/química , Análise de Sequência de DNA , Fosfolipídeos/análiseRESUMO
An indigenous chromate-resistant bacterial strain isolated from tannery effluent was identified based on morphological, biochemical, and 16S rRNA gene sequencing, as Enterobacter cloacae UT25. It was found to resist heavy metal ions such as Cr (VI), Pb (II), Cu (II), Co (II), Ni (II), Hg (II), and Zn (II) and antibiotics. The strain was able to remove 89 and 86% chromate, after 24 h of incubation in a Luria-Bertani (LB) medium at an initial Cr (VI) concentration of 1000 and 1500 µg/ml, respectively. Minimum inhibitory concentration (MIC) was observed for chromate to be 80,000 and 1850 µg/ml, after 48 h of incubation in LB and acetate minimal media (AMM), respectively. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis showed discrete cells with intact and smooth cell walls and homogenous cytoplasm in the absence of metal stress, whereas chromate stress caused cell lysis and reduction in size, which was a characteristic response to Cr (VI) toxicity. Energy Dispersive X-Ray Spectroscopy (EDX) confirmed the adsorption of oxyanions to the cell wall which was one of the Cr (VI) removal mechanisms by the bacterium. Atomic Force Microscopy (AFM) micrographs of chromate-untreated and treated cells revealed Root Mean Square roughness (Rq) values of 16.25 and 11.26 nm, respectively, indicating less roughness in the presence of stress. The partial gene sequence of class 1 integrons (intI1) of strain UT25 showed 94% homology with intI1 gene of strain Enterobacter hormaechei strain ECC59 plasmid pECC59-1. The present analysis highlighted the potential of E. cloacae UT25 as a promissory bacterium that could be applied in removing chromate from polluted environments.
Assuntos
Cromatos , Metais Pesados , Cromo , Enterobacter cloacae/genética , RNA Ribossômico 16S/genética , Metais Pesados/toxicidade , Bactérias/genética , Biodegradação AmbientalRESUMO
Toxic heavy metal/oxyanion contamination has increased severely through the last decades. In this study, 169 native haloarchaeal strains were isolated from different saline and hypersaline econiches of Iran. After providing pure culture and performing morphological, physiological, and biochemical tests, haloarchaea resistance toward arsenate, selenite, chromate, cadmium, zinc, lead, copper, and mercury were surveyed using an agar dilution method. On the basis of minimum inhibitory concentrations (MICs), the least toxicities were found with selenite and arsenate, while the haloarchaeal strains revealed the highest sensitivity for mercury. On the other hand, the majority of haloarchaeal strains exhibited similar responses to chromate and zinc, whereas the resistance level of the isolates to lead, cadmium, and copper was very heterogeneous. 16 S ribosomal RNA (rRNA) gene sequence analysis revealed that most haloarchaeal strains belong to the Halorubrum and Natrinema genera. The obtained results from this study showed that among the identified isolates, Halococcus morrhuae strain 498 had an exceptional resistance toward selenite and cadmium (64 and 16 mM, respectively). Also, Halovarius luteus strain DA5 exhibited a remarkable tolerance against copper (32 mM). Moreover, strain Salt5, identified as Haloarcula sp., was the only strain that could tolerate all eight tested heavy metals/oxyanions and had a significant tolerance of mercury (1.5 mM).
Assuntos
Mercúrio , Metais Pesados , Cobre , Arseniatos , Cádmio , Ecossistema , Cromatos , ZincoRESUMO
Manganese is an essential trace element; nevertheless, on conditions of overload, it becomes toxic, with neurotoxicity being the main concern. Chromate is a well-known human carcinogen. The underlying mechanisms seem to be oxidative stress as well as direct DNA damage in the case of chromate, but also interactions with DNA repair systems in both cases. However, the impact of manganese and chromate on DNA double-strand break (DSB) repair pathways is largely unknown. In the present study, we examined the induction of DSB as well as the effect on specific DNA DSB repair mechanisms, namely homologous recombination (HR), non-homologous end joining (NHEJ), single strand annealing (SSA), and microhomology-mediated end joining (MMEJ). We applied DSB repair pathway-specific reporter cell lines, pulsed field gel electrophoresis as well as gene expression analysis, and investigated the binding of specific DNA repair proteins via immunoflourescence. While manganese did not seem to induce DNA DSB and had no impact on NHEJ and MMEJ, HR and SSA were inhibited. In the case of chromate, the induction of DSB was further supported. Regarding DSB repair, no inhibition was seen in the case of NHEJ and SSA, but HR was diminished and MMEJ was activated in a pronounced manner. The results indicate a specific inhibition of error-free HR by manganese and chromate, with a shift towards error-prone DSB repair mechanisms in both cases. These observations suggest the induction of genomic instability and may explain the microsatellite instability involved in chromate-induced carcinogenicity.
Assuntos
Cromatos , Manganês , Humanos , Manganês/toxicidade , Cromatos/toxicidade , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Reparo do DNA por Junção de Extremidades , DNA/metabolismoRESUMO
Hexavalent chromium, Cr(VI), is a known carcinogen and environmental health concern. It has been established that reactive oxygen species, genomic instability, and DNA damage repair deficiency are important contributors to the Cr(VI)-induced carcinogenesis mechanism. However, some hallmarks of cancer remain under-researched regarding the mechanism behind Cr(VI)-induced carcinogenesis. Increased lipogenesis is important to carcinogenesis and tumorigenesis in multiple types of cancers, yet the role increased lipogenesis has in Cr(VI) carcinogenesis is unclear. We report here that Cr(VI)-induced transformation of three human lung cell lines (BEAS-2B, BEP2D, and WTHBF-6) resulted in increased lipogenesis (palmitic acid levels), and Cr(VI)-transformed cells had an increased expression of key lipogenesis proteins (ATP citrate lyase [ACLY], acetyl-CoA carboxylase [ACC1], and fatty acid synthase [FASN]). We also determined that the Cr(VI)-transformed cells did not exhibit an increase in fatty acid oxidation or lipid droplets compared to their passage-matched control cells. Additionally, we observed increases in ACLY, ACC1, and FASN in lung tumor tissue compared with normal-adjacent lung tissue (in chromate workers that died of chromate-induced tumors). Next, using a known FASN inhibitor (C75), we treated Cr(VI)-transformed BEAS-2B with this inhibitor and measured cell growth, FASN protein expression, and growth in soft agar. We observed that FASN inhibition results in a decreased protein expression, decreased cell growth, and the inhibition of colony growth in soft agar. Next, using shRNA to knock down the FASN protein in Cr(VI)-transformed BEAS-2B cells, we saw a decrease in FASN protein expression and a loss of the xenograft tumor development of Cr(VI)-transformed BEAS-2B cells. These results demonstrate that FASN is important for Cr(VI)-transformed cell growth and cancer properties. In conclusion, these data show that Cr(VI)-transformation in vitro caused an increase in lipogenesis, and that this increase is vital for Cr(VI)-transformed cells.
Assuntos
Cromatos , Lipogênese , Humanos , Cromatos/efeitos adversos , Xenoenxertos , Ágar , Células Epiteliais/metabolismo , Cromo/metabolismo , Transformação Celular Neoplásica/induzido quimicamente , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Carcinogênese/metabolismo , Pulmão/patologiaRESUMO
OBJECTIVE: Aim: The aim of the research is to study the immunohistochemical markers of the endothelium of blood vessels and myocardial ventricles under chronic exposure to sodium bichromate and lindane, as well as in conjunction with damaging biochemical agents contained in the blood. PATIENTS AND METHODS: Materials and Methods: The object of the experiment was outbred white mice (males). The study was carried out in 3 groups: 1st group - control, 2nd group - exposure to sodium bichromate 5 mg/kg, 3rd group - exposure to organochlorine pesticide lindane 100 mg/kg. In this experiment authors used the next methods: immunohistochemical method., biochemical research, statistical analysis. RESULTS: Results: The data obtained from an experimental study show that the level of cardiomarkers in blood plasma is characterized by different changes when exposed to these two compounds. Basically, the predominance of the effect of sodium bichromate on the LDH level is noted as compared to the effect of lindane; on the CK-MB level, their effects were the same, i.e., there is an increase in their level in blood plasma. CONCLUSION: Conclusions: Thus, long-term exposure to sodium bichromate leads to the activation of angiogenesis, destruction of the integrity of the endothelium, and this, in turn, leads to reparative changes located around in the myocardial cells.
Assuntos
Hexaclorocicloexano , Hidrocarbonetos Clorados , Masculino , Camundongos , Animais , Hexaclorocicloexano/toxicidade , Miocárdio , CromatosRESUMO
Hexavalent chromium [Cr(VI)] is a global environmental pollutant and human lung carcinogen. However, the mechanisms of Cr(VI) carcinogenesis are not well defined. Cr(VI)-altered gene expression has been reported in the literature and is implicated in numerous mechanisms of Cr(VI) carcinogenesis. MicroRNAs (miRNAs) play a key role in controlling gene expression and are associated with carcinogenic mechanisms. To date no studies have evaluated global changes in miRNA expression in human cells after Cr(VI) exposure. We used RNA sequencing to evaluate how a particulate Cr(VI) compound (zinc chromate), the most potent form of Cr(VI), alters global miRNA expression after acute (24 h) or prolonged (72 and 120 h) exposure to 0.1, 0.2 and 0.3 µg/cm2 zinc chromate in an immortalized, non-cancerous human lung cell line (WTHBF-6). Particulate Cr(VI) significantly affected expression of miRNAs at all time points and concentrations tested. We also found the number of significantly downregulated miRNAs increased in a time- and concentration-dependent manner and many miRNAs were upregulated after 24 h exposure at the intermediate concentration tested. Pathway analyses of the differentially expressed miRNAs predicted miRNAs target pathways of Cr(VI) carcinogenesis in a time- and concentration-dependent manner. These data are the first to evaluate global changes in miRNA expression in human lung cells after Cr(VI) exposure and indicate miRNAs may play a key role in pathways of Cr(VI) carcinogenesis.
Assuntos
Carcinogênese/induzido quimicamente , Carcinógenos/toxicidade , Cromo/toxicidade , Pulmão/efeitos dos fármacos , MicroRNAs/genética , Transdução de Sinais/efeitos dos fármacos , Carcinogênese/genética , Linhagem Celular , Cromatos/toxicidade , Expressão Gênica/efeitos dos fármacos , Humanos , Transdução de Sinais/genética , Compostos de Zinco/toxicidadeRESUMO
An integrated approach involving vermicompost, chromate reducing bacteria and AMF was tested to manage the toxic impacts of Cr(VI) on Ocimum basilicum as a model plant. Pot experiments were conducted on O. basilicum plants in an artificially Cr(VI)-contaminated soil in two phases of experiment as bioinoculants experiment and vermicompost experiment. In the first phase of the bioinoculants experiment the series of gradient concentrations of Cr(VI) (0, 25, 50 and 100 mg kg-1 in soil) were evaluated with previously isolated four efficient Cr(VI)-reducing rhizo-bacterial strains (Bacillus Cereus strain SUCR 44, BC; Microbacterium sp. strain SUCR 140, MB; Bacillus thuringiensis strain SUCR186, BT; and Bacillus subtilis strain SUCR188; BS) along with Arbuscular Mycorrhizal Fungus-Glomus fasciculatum (GF) in alone and in co-inoculation form. In the second experiment (vermicompost) the best performing strain (MB) was tested alone or in combination with GF along with different doses of vermicompost. It was observed that vermicompost by itself could be useful in decreasing the bioavailable Cr(VI), uptake of Cr besides improving the nutritional status of plants. The vermicompost also played an important and indirect role and improved herb yield by supporting the multiplication of MB (Microbacterium sp.), an efficient chromate reducing rhizobacteria, that further decreased the bioavailable and toxic form of Cr and improved population and colonization of GF too. The translocation of Cr(VI) was averted through improved colonization of GF, also prevented higher accumulation of Cr in aerial parts (leafy herb) of O. basilicum.
Assuntos
Alphaproteobacteria , Micorrizas , Ocimum basilicum , Poluentes do Solo , Bacillus cereus , Cromatos , Cromo , Plantas , Solo , Microbiologia do Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidadeRESUMO
Removal of chromate (CrO42-) and pertechnetate (TcO4-) from the Hanford Low Activity Waste (LAW) is beneficial as it impacts the cost, life cycle, operational complexity of the Waste Treatment and Immobilization Plant (WTP), and integrity of vitrified glass for nuclear waste disposal. Here, we report the application of [MoIV3S13]2- intercalated layer double hydroxides (LDH-Mo3S13) for the removal of CrO42- as a surrogate for TcO4-, from ppm to ppb levels from water and a simulated LAW off-gas condensate of Hanford's WTP. LDH-Mo3S13 removes CrO42- from the LAW condensate stream, having a pH of 7.5, from ppm (â¼9.086 × 104 ppb of Cr6+) to below 1 ppb levels with distribution constant (Kd) values of up to â¼107 mL/g. Analysis of postadsorbed solids indicates that CrO42- removal mainly proceeds by reduction of Cr6+ to Cr3+. This study sets the first example of a metal sulfide intercalated LDH for the removal of CrO42-, as relevant to TcO4-, from the simulated off-gas condensate streams of Hanford's LAW melter which contains highly concentrated competitive anions, namely F-, Cl-, CO32-, NO3-, BO33-, NO2-, SO42-, and B4O72-. LDH-Mo3S13's remarkable removal efficiency makes it a promising sorbent to remediate CrO42-/TcO4- from surface water and an off-gas condensate of nuclear waste.