RESUMO
This paper consists of the evaluation in regards to the ecotoxicological effectiveness of a treatment applied to a coal mining waste. The treatment consisted of separating the particles based on gravimetric concentration in spirals, generating three fractions: heavy, intermediate, and light, with high, moderate, and low pyrite content, respectively. The intermediate fraction represents the larger disposal volume of the waste on soils. To evaluate the effectiveness of the treatment, metal determination and bioassays Eisenia andrei, Folsomia candida, Lactuca sativa, Daphnia similis, and Raphidocelis subcapitata were applied to the intermediary fraction. To evaluate the toxicity to aquatic organisms, elutriates were generated from the unprocessed waste and the intermediate fraction. The intermediate fraction showed a decrease of metal concentrations compared to the untreated waste. Metal concentrations in the intermediate fraction were below the Brazilian thresholds for soil quality. Avoidance bioassay with E. andrei and germination tests of L. sativa showed no significant effects. The bioassay with F. candida indicated a significant reduction in reproduction at the highest doses used (24% and 50%). Bioassays with D. similis and R. subcapitata revealed a reduction in toxicity of the intermediate fraction compared to the untreated waste. However, the toxicity levels of the intermediate fraction to aquatic organisms still require attention, especially in regards to pH that played a crucial role in the toxicity. Finally, the results suggest that the treatment performed on the coal waste was efficient, even though significant toxicity have still been detected in the treated waste and additional steps are still required for adequate final disposal.
Assuntos
Artrópodes , Minas de Carvão , Poluentes do Solo , Animais , Aliivibrio fischeri , Solo , Metais/farmacologia , Poluentes do Solo/análise , MineraçãoRESUMO
An essential requirement for cells to sustain a high proliferating rate is to be paired with enhanced protein synthesis through the production of ribosomes. For this reason, part of the growth-factor signaling pathways, are devoted to activate ribosome biogenesis. Enhanced production of ribosomes is a hallmark in cancer cells, which is boosted by different mechanisms. Here we report that the nucleolar tumor-protein MageB2, whose expression is associated with cell proliferation, also participates in ribosome biogenesis. Studies carried out in both siRNA-mediated MageB2 silenced cells and CRISPR/CAS9-mediated MageB2 knockout (KO) cells showed that its expression is linked to rRNA transcription increase independently of the cell proliferation status. Mechanistically, MageB2 interacts with phospho-UBF, a protein which causes the recruitment of RNA Pol I pre-initiation complex required for rRNA transcription. In addition, cells expressing MageB2 displays enhanced phospho-UBF occupancy at the rDNA gene promoter. Proteomic studies performed in MageB2 KO cells revealed impairment in ribosomal protein (RPs) content. Functionally, enhancement in rRNA production in MageB2 expressing cells, was directly associated with an increased dynamic in protein synthesis. Altogether our results unveil a novel function for a tumor-expressed protein from the MAGE-I family. Findings reported here suggest that nucleolar MageB2 might play a role in enhancing ribosome biogenesis as part of its repertoire to support cancer cell proliferation.
Assuntos
Antígenos de Neoplasias/metabolismo , Proteínas de Neoplasias/metabolismo , Ribossomos/metabolismo , Antígenos de Neoplasias/fisiologia , Linhagem Celular Tumoral , Nucléolo Celular/metabolismo , Proliferação de Células/genética , DNA Ribossômico/genética , DNA Ribossômico/metabolismo , Células HCT116 , Células HEK293 , Humanos , Proteínas de Neoplasias/fisiologia , Neoplasias/genética , Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Pol1 do Complexo de Iniciação de Transcrição/metabolismo , Regiões Promotoras Genéticas/genética , Biossíntese de Proteínas , Processamento de Proteína Pós-Traducional , Proteômica , RNA Polimerase I/metabolismo , RNA Ribossômico/biossíntese , Ribossomos/genética , Transcrição Gênica/genéticaRESUMO
There are two principal types of nickel (Ni) deposits: sulfide and laterite ores. Interest in low-grade Ni-laterite ores has increased in recent years as high-grade Ni-sulfide deposits are being quickly depleted. However, processing of Ni laterites has proven technically difficult and costly, and the development of alternative low-cost biotechnologies for Ni solubilization has been encouraged. In this context, by the first time, a sample of Brazilian Ni-laterite ore was analyzed mineralogically and subjected to bioleaching tests using a heterotrophic Bacillus subtilis strain. SEM-analysis indicated that the primary Ni carrier mineral is goethite. Chemical analysis of different grain size fractions indicated a homogeneous distribution of Ni. XRF-analysis showed that the ore consists mainly in lizardite (32.6% MgO) and contains1.0% NiO (0.85% Ni). Bioleaching batch experiments demonstrated that about 8.1% Ni (0.7 mg Ni/g ore) were solubilized by the B. subtilis after 7 days. Application of microwave heating as a Ni-laterite pretreatment was also tested. This pretreatment increased the bioextraction of Ni from 8% to 26% (2.3 mg Ni g-1 ore).
Assuntos
Bacillus subtilis/metabolismo , Biotecnologia/tendências , Níquel/química , Bacillus subtilis/química , Brasil , Compostos de Ferro/química , Minerais/químicaRESUMO
The potential of Bioclastic Granules - BG (calcium-carbonate-based material) using the algae Lithothamnium calcareum as sorbent for the removal of Cd(II) from aqueous solutions by sorption was evaluated through batch and continuous systems tests using a fixed-bed column. Sorption process variables, in particular pH (2-7), particle size (<38-300â µm), initial BG concentration (0.1-1.0â gâ L-1), initial Cd(II) concentrations (5-400â mgâ L-1) and contact time (5-240â min), were evaluated. Adsorption isotherm profiles of Cd(II) per BG were similar to an L-type, or Langmuir type, with the adsorption forming a monolayer of approximately 0.61â µm, with a qmax of 188.74â mgâ g-1 and kL of 0.710â Lâ mg-1. Thomas's model considers that sorption is not limited to a chemical reaction but is controlled by mass transfer at the interface. In the present study, the obtained value of kTh was 0.895â mLâ h-1â mg-1, reaching a sorption capacity qo of 124.4â mgâ g-1. For the Yoon-Nelson model, it was possible to obtain two important parameters to describe the behavior of the column, the rate constant (kYN), obtaining a value of 0.09â h-1 and an τ of 82.12â h corresponding to the time required for sorption to occur of 50% of the solute in the rupture curve. X-ray diffraction and scanning electron microscopy analyses coupled to the X-ray dispersive energy system (SEM/EDS) of the BG after the Cd(II) ion sorption tests evidenced the formation of crystals with the prevalence of a new mineral phase (otavite).
Assuntos
Cádmio/química , Poluentes Químicos da Água/química , Purificação da Água , Adsorção , Concentração de Íons de Hidrogênio , CinéticaRESUMO
MAGE-A (Melanoma Antigen Genes-A) are tumor-associated proteins with expression in a broad spectrum of human tumors and normal germ cells. MAGE-A gene expression and function are being increasingly investigated to better understand the mechanisms by which MAGE proteins collaborate in tumorigenesis and whether their detection could be useful for disease prognosis purposes. Alterations in epigenetic mechanisms involved in MAGE gene silencing cause their frequent co-expression in tumor cells. Here, we have analyzed the effect of MAGE-A gene co-expression and our results suggest that MageA6 can potentiate the androgen receptor (AR) co-activation function of MageA11. Database search confirmed that MageA11 and MageA6 are co-expressed in human prostate cancer samples. We demonstrate that MageA6 and MageA11 form a protein complex resulting in the stabilization of MageA11 and consequently the enhancement of AR activity. The mechanism involves association of the Mage A6-MHD domain to MageA11, prevention of MageA11 ubiquitinylation on lysines 240 and 245 and decreased proteasome-dependent degradation. We experimentally demonstrate here for the first time that two MAGE-A proteins can act together in a non-redundant way to potentiate a specific oncogenic function. Overall, our results highlight the complexity of the MAGE gene networking in regulating cancer cell behavior.
Assuntos
Antígenos de Neoplasias/genética , Antígenos de Neoplasias/metabolismo , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Antígenos de Neoplasias/química , Linhagem Celular Tumoral , Expressão Gênica , Humanos , Masculino , Complexos Multiproteicos/química , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Proteínas de Neoplasias/química , Neoplasias Embrionárias de Células Germinativas/genética , Neoplasias Embrionárias de Células Germinativas/metabolismo , Domínios e Motivos de Interação entre Proteínas , Estabilidade Proteica , Receptores Androgênicos/metabolismo , Neoplasias Testiculares/genética , Neoplasias Testiculares/metabolismo , UbiquitinaçãoRESUMO
Since its discovery in 1991, the knowledge about the tumor specific melanoma antigen gene (MAGE-I) family has been continuously increasing. Initially, MAGE-I proteins were considered as selective targets for immunotherapy. More recently, emerging data obtained from different cellular mechanisms controlled by MAGE-I proteins suggest a key role in the regulation of important pathways linked to cell proliferation. This is in part due to the ability of some MAGE-I proteins to control the p53 tumor suppressor. In this review, we focus on the mechanisms proposed to explain how MAGE-I proteins affect p53 functions.