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1.
Water Sci Technol ; 87(12): 3017-3030, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37387427

RESUMO

Bacterial biomasses are suitable and inexpensive biosorbents for the removal of metal ions. The Gram-negative betaproteobacterium Cupriavidus necator H16 is found in soil and freshwater environments. In this study, C. necator H16 was used to remove chromium (Cr), arsenic (As), aluminum (Al), and cadmium (Cd) ions from water. Minimum inhibition concentration (MIC) values of C. necator to Cr, As, Al, and Cd were found as 76, 69, 341, and 275 mg/L, respectively. The highest rates of Cr, As, Al, and Cd bioremoval were 45, 60, 54, and 78%, respectively. pH levels between 6.0 and 8.0 and an average temperature of 30 °C were optimum for the most efficient bioremoval. Scanning electron microscopy (SEM) images of Cd-treated cells showed that the morphology of the cells was significantly impaired compared to the control. Shifts in the Fourier transform infrared spectroscopy analysis (FTIR) spectra of the Cd-treated cell walls also confirmed the presence of active groups. As a result, it can be said that C. necator H16 has a moderate bioremoval efficiency for Cr, As, and Al and a high bioremoval efficiency for Cd.


Assuntos
Arsênio , Cupriavidus necator , Cádmio , Água , Metais , Alumínio , Cromo , Íons
2.
World J Microbiol Biotechnol ; 38(3): 45, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-35075546

RESUMO

The number of studies on the removal of hazardous metals from water using genetic engineering technologies is growing. A high rate of metal ion removal from the environment is ensured, particularly through the expression of cysteine and thiol-rich proteins such as metallothioneins in bacterial cells. In this study, we used recombinant strains created by cloning the human metallothioneins MT2A and MT3 into Escherichia coli Jm109 to assess the removal and reduction of hexavalent chromium (Cr(VI)) from aqueous solutions. MT2A was the most effective strain in both Cr(VI) removal (89% in 25 mg/L Cr(VI)) and Cr(VI) reduction (76% in 25 mg/L Cr(VI)). The amount of Cr adsorbed per dry cell by the MT2A strain was 22 mg/g. The biosorption of total Cr was consistent with the Langmuir isotherm model. Scanning electron microscope (SEM) images revealed that the morphological structures of Cr(VI)-treated cells were significantly damaged when compared to control cells. Scanning transmission electron microscope (STEM) images showed black spots in the cytoplasm of cells treated with Cr(VI). Shifts in the Fourier transform infrared spectroscopy analysis (FTIR) spectra of the cells treated with Cr(VI) showed that the groups interacting with Cr were hydroxyl, amine, amide I, amide II, phosphoryl and carbonyl. When all of the experimental data was combined, it was determined that both MT2A and MT3 were effective in removing Cr(VI) from aqueous solutions, but MT2A was more effective, indicating that MT2A may be employed as a biotechnological tool.


Assuntos
Biodegradação Ambiental , Cromo/metabolismo , Escherichia coli/metabolismo , Metalotioneína/metabolismo , Metais/metabolismo , Adsorção , Biotecnologia/métodos , Clonagem Molecular , Escherichia coli/genética , Engenharia Genética/métodos , Humanos , Metalotioneína/genética , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos
3.
Environ Sci Pollut Res Int ; 27(28): 35626-35637, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32601870

RESUMO

Penconazole is one of the most widely used fungicides all over the world, and since it spreads to large environments, its toxic effects on non-target organisms are of great concern. The toxic effects of penconazole on crayfish (Astacus leptodactylus), which is a bioindicator in freshwater ecosystems and consumed economically, are not known. Therefore, in this study, the purpose was to contribute to the literature on the potential harmful effects of penconazole on a non-target species, Astacus leptodactylus. For this aim, the acute toxicity (96 h) of penconazole was examined. The 96-h LC50 value of penconazole was detected as 18.7 mg L-1. Four concentrations of penconazole (18.7 mg L-1, 9.35 mg L-1, 4.68 mg L-1, 2.34 mg L-1) were applied to crayfish for 96 h. The results showed that penconazole had destructive effects on esterase mechanisms by inhibiting acetylcholinesterase (AChE) and carboxylesterase (CaE) activities. Significant increases were observed in all antioxidant parameters (superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), reduced glutathione (GSH), malondialdehyde (MDA)) in all doses except the lowest concentration (2.34 mg L-1). All adenosine triphosphatase (ATPase) activities (Na+/K+-ATPase, Mg2+-ATPase, Ca2+-ATPase, total ATPase) had significant dose-related inhibition in both gill and muscle tissues. In summary, our findings show that acute penconazole administration to crayfish causes significant toxic effects on esterase, antioxidative parameters, and metabolic enzymes.


Assuntos
Astacoidea , Fungicidas Industriais , Animais , Antioxidantes , Catalase , Ecossistema , Glutationa , Glutationa Peroxidase , Glutationa Transferase , Estresse Oxidativo , Superóxido Dismutase , Triazóis
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