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Rieder GS, Duarte T, Delgado CP, Rodighiero A, Nogara PA, Orian L, Aschner M, Dalla Corte CL, Da Rocha JBT. Interplay between diphenyl diselenide and copper: Impact on D. melanogaster survival, behavior, and biochemical parameters. Comp Biochem Physiol C Toxicol Pharmacol 2024; 281:109899. [PMID: 38518983 DOI: 10.1016/j.cbpc.2024.109899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/11/2024] [Accepted: 03/17/2024] [Indexed: 03/24/2024]
Abstract
Copper (Cu2+) is a biologically essential element that participates in numerous physiological processes. However, elevated concentrations of copper have been associated with cellular oxidative stress and neurodegenerative diseases. Organo‑selenium compounds such as diphenyl diselenide (DPDS) have in vitro and in vivo antioxidant properties. Hence, we hypothesized that DPDS may modulate the toxicity of Cu2+ in Drosophila melanogaster. The acute effects (4 days of exposure) caused by a high concentration of Cu2+ (3 mM) were studied using endpoints of toxicity such as survival and behavior in D. melanogaster. The potential protective effect of low concentration of DPDS (20 μM) against Cu2+ was also investigated. Adult flies aged 1-5 days post-eclosion (both sexes) were divided into four groups: Control, DPDS (20 μM), CuSO4 (3 mM), and the combined exposure of DPDS (20 μM) and CuSO4 (3 mM). Survival, biochemical, and behavioral parameters were determined. Co-exposure of DPDS and CuSO4 increased acetylcholinesterase (AChE) activity and the generation of reactive oxygen species (ROS as determined by DFCH oxidation). Contrary to our expectation, the co-exposure reduced survival, body weight, locomotion, catalase activity, and cell viability in relation to control group. Taken together, DPDS potentiated the Cu2+ toxicity.
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Affiliation(s)
- G S Rieder
- Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil. https://twitter.com/RiederSchmitt
| | - T Duarte
- Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil. https://twitter.com/tttamie
| | - C P Delgado
- Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil. https://twitter.com/cassiapdelgado
| | - A Rodighiero
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - P A Nogara
- Instituto Federal de Educação, Ciência e Tecnologia Sul-rio-grandense (IFSul), Av. Leonel de Moura Brizola, 2501, 96418-400 Bagé, RS, Brazil. https://twitter.com/nogara_pablo
| | - L Orian
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy. https://twitter.com/_LauraOrian
| | - M Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - C L Dalla Corte
- Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil
| | - J B T Da Rocha
- Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil; Department of Biochemistry, Institute of Basic Health Science, Federal University of Rio Grande do Sul, Porto Alegre, RS 90035-003, Brazil.
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Dalla Tiezza M, Bickelhaupt FM, Flohé L, Maiorino M, Ursini F, Orian L. A dual attack on the peroxide bond. The common principle of peroxidatic cysteine or selenocysteine residues. Redox Biol 2020; 34:101540. [PMID: 32428845 PMCID: PMC7231847 DOI: 10.1016/j.redox.2020.101540] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/01/2020] [Accepted: 04/08/2020] [Indexed: 01/07/2023] Open
Abstract
The (seleno)cysteine residues in some protein families react with hydroperoxides with rate constants far beyond those of fully dissociated low molecular weight thiol or selenol compounds. In case of the glutathione peroxidases, we could demonstrate that high rate constants are achieved by a proton transfer from the chalcogenol to a residue of the active site [Orian et al. Free Radic. Biol. Med. 87 (2015)]. We extended this study to three more protein families (OxyR, GAPDH and Prx). According to DFT calculations, a proton transfer from the active site chalcogenol to a residue within the active site is a prerequisite for both, creating a chalcogenolate that attacks one oxygen of the hydroperoxide substrate and combining the delocalized proton with the remaining OH or OR, respectively, to create an ideal leaving group. The “parking postions” of the delocalized proton differ between the protein families. It is the ring nitrogen of tryptophan in GPx, a histidine in GAPDH and OxyR and a threonine in Prx. The basic principle, however, is common to all four families of proteins. We, thus, conclude that the principle outlined in this investigation offers a convincing explanation for how a cysteine residue can become peroxidatic. In some protein families, (seleno)cysteine residues react with hydroperoxides with very high rate constants. In GPx, DFT models of the oxidation of the catalytic site support a two-step mechanism for the H2O2 reduction. This mechanism is here found to operate in other thiol-based enzymes, i.e. OxyR, GAPDH and Prx.
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Affiliation(s)
- M Dalla Tiezza
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35131, Padova, Italy
| | - F M Bickelhaupt
- Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, the Netherlands; Institute for Molecules and Materials (IMM), Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
| | - L Flohé
- Dipartimento di Medicina Molecolare, Università degli Studi di Padova, V.le G. Colombo 3, 35121, Padova, Italy; Departamento de Bioquímica, Universidad de la República, Avda. General Flores 2125, 11800, Montevideo, Uruguay
| | - M Maiorino
- Dipartimento di Medicina Molecolare, Università degli Studi di Padova, V.le G. Colombo 3, 35121, Padova, Italy
| | - F Ursini
- Dipartimento di Medicina Molecolare, Università degli Studi di Padova, V.le G. Colombo 3, 35121, Padova, Italy
| | - L Orian
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35131, Padova, Italy.
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Abstract
The static electric polarizabilities (α) of a quadrupolar squaraine dye are investigated in silico, either as the excess polarizability, i.e., the change from the ground to the lowest excited state, Δα, or as those of the two states separately, depending on the approach. The polarizabilities are worked out by making use of the energy and dipole moment Taylor expansions as a function of the electric field (E), in which α is represented by the quadratic and linear terms, respectively, and also by means of the linear response approach. Dipoles and energies are computed at a few values of the electric field, with different strategies that consider the geometry of the molecule either frozen in the ground state or relaxed at each E value. From a physical standpoint, the most appropriate approach to describing the molecular polarizability depends on the processes in which the molecule is involved: for example, fluorescence methods provide information about relaxed excited states, and absorption methods are used to determine the polarizability changes of excited states frozen in the ground-state conformation. We show that the excited-state polarizability does not strongly differ from the ground-state polarizability when the field is applied along the main axis of the squaraine. In contrast, remarkable differences are found when the field is applied perpendicular to the molecular plane due to a large geometrical distortion of the molecular backbone.
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Affiliation(s)
- L Orian
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova , Via Marzolo 1, 35131 Padova, Italy
| | - R Pilot
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova , Via Marzolo 1, 35131 Padova, Italy.,Consorzio INSTM, Via G. Giusti 9, 50121 Firenze, Italy
| | - R Bozio
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova , Via Marzolo 1, 35131 Padova, Italy.,Consorzio INSTM, Via G. Giusti 9, 50121 Firenze, Italy
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Dunn CJ, Ionescu D, Kunimatsu N, Luckhurst GR, Orian L, Polimeno A. A Novel Magnetohydrodynamic Experiment: Step-Rotation of a Nematic Subject to a Magnetic Field. J Phys Chem B 2000. [DOI: 10.1021/jp002073a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Polimeno A, Orian L, Martins AF, Gomes AE. Simulations of flow-induced director structures in nematic liquid crystals through leslie-ericksen equations. I. Computational methodology in two dimensions. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 2000; 62:2288-2300. [PMID: 11088696 DOI: 10.1103/physreve.62.2288] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/1999] [Revised: 01/21/2000] [Indexed: 05/23/2023]
Abstract
A computational treatment of the constitutive equations of nematodynamics, based on the Leslie-Ericksen approach, is presented and discussed for a rotating planar nematic sample subjected to a constant magnetic field. The dynamics of the velocity v and director n fields is taken into account exactly. Coupled partial differential equations suitable to be solved numerically are worked out, in terms of derived functionals of v and n and of their spatial and time derivatives. Time-dependent patterns of the director are obtained using a finite-difference scheme in a spatial polar grid. Several experimental situations are analyzed, corresponding to common experimental setups: continuously rotating samples for different values of the rotational speed; 30 degrees and 90 degrees step-rotation experiments. A comparison is made to existing approximate treatments. Dependence upon the sample dimension is also discussed.
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Affiliation(s)
- A Polimeno
- Department of Physical Chemistry, University of Padova, Via Loredan 2, 35131 Padova, Italy
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Martins AF, Gomes AE, Polimeno A, Orian L. Simulations of flow-induced director structures in nematic liquid crystals through leslie-ericksen equations. II. Interpretation Of NMR experiments in liquid crystal polymers. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 2000; 62:2301-2309. [PMID: 11088697 DOI: 10.1103/physreve.62.2301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/1999] [Revised: 01/21/2000] [Indexed: 05/23/2023]
Abstract
Computationally exact and approximate solutions of the Leslie-Ericksen equations for nematic liquid crystals in two dimensions are employed to calculate director distributions in cylindrical samples, rotating under the influence of a magnetic field. In particular, the time evolution of systems prepared initially in metastable states with respect to the magnetic field is investigated, and calculated director distributions are used to interpret rheo-NMR experiments in nematic liquid crystal polymers.
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Affiliation(s)
- AF Martins
- Departamento de Cieinsertion markncia dos Materiais, Faculdade de Cieinsertion markncias e Tecnologia, Universidade Nova de Lisboa, P-2825-114 Monte de Caparica, Portugal
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