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1.
Sci Rep ; 14(1): 20655, 2024 09 04.
Artículo en Inglés | MEDLINE | ID: mdl-39232193

RESUMEN

During their development, amphibians undergo various physiological processes that may affect their susceptibility to environmental pollutants. Naturally occurring fluctuations caused by developmental events are often overlooked in ecotoxicological studies. Our aim is to investigate how biomarkers of oxidative stress are modulated at different stages of larval development in the Amazonian amphibian species, Physalaemus ephippifer. The premetamorphosis, prometamorphosis and metamorphic climax stages were used to analyze total antioxidant capacity (ACAP), glutathione S-transferase (GST) activity, lipid peroxidation (LPO) levels and the expression of genes nrf2, gst, gsr (glutathione reductase) and gclc (glycine-cysteine ligase, catalytic subunit). Although there was no difference in ACAP and the genes expression among the studied stages, individuals from the premetamorphosis and prometamorphosis showed higher GST activity than ones under the climax. LPO levels were highest in individuals from the metamorphic climax. The present study suggests that the oxidative status changes during ontogeny of P. ephippifer tadpoles, especially during the metamorphic climax, the most demanding developmental phase. Variations in the redox balance at different developmental stages may lead to a divergent response to pollution. Therefore, we recommend that studies using anuran larvae as biomonitors consider possible physiological differences during ontogeny in their respective analyses.


Asunto(s)
Anuros , Glutatión Transferasa , Larva , Peroxidación de Lípido , Oxidación-Reducción , Estrés Oxidativo , Animales , Anuros/metabolismo , Anuros/crecimiento & desarrollo , Larva/metabolismo , Larva/crecimiento & desarrollo , Glutatión Transferasa/metabolismo , Antioxidantes/metabolismo , Metamorfosis Biológica , Biomarcadores/metabolismo
4.
AMB Express ; 7(1): 87, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28452041

RESUMEN

Baeyer-Villiger monooxygenases are recognized by their ability and high selectivity as oxidative biocatalysts for the generation of esters or lactones using ketones as starting materials. These enzymes represent valuable tools for biooxidative syntheses since they can catalyze reactions that otherwise involve strong oxidative reagents. In this work, we present a novel enzyme, the Type I Baeyer-Villiger monooxygenase from Leptospira biflexa. This protein is phylogenetically distant from other well-characterized BVMOs. In order to study this new enzyme, we cloned its gene, expressed it in Escherichia coli and characterized the substrate scope of the Baeyer-Villiger monooxygenase from L. biflexa as a whole-cell biocatalyst. For this purpose, we performed the screening of a collection of ketones with variable structures and sizes, namely acyclic ketones, aromatic ketones, cyclic ketones, and fused ketones. As a result, we observed that this biocatalyst readily oxidized linear- and branched- medium-chain ketones, alkyl levulinates and linear ketones with aromatic substituents with excellent regioselectivity. In addition, this enzyme catalyzed the oxidation of 2-substituted cycloketone derivatives but showed an unusual selection against substituents in positions 3 or 4 of the ring.

5.
Bioorg Med Chem Lett ; 23(9): 2718-20, 2013 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-23535329

RESUMEN

A novel and stereoselective synthetic route towards carba-C-nucleosides was investigated applying an enantiodivergent biooxidation strategy by two different Baeyer-Villiger monooxygenases. Within only three chemo-enzymatic steps it was possible to introduce four chiral centers starting from commercially available non-chiral starting material.


Asunto(s)
Carba-azúcares/química , Oxigenasas de Función Mixta/metabolismo , Nucleósidos/química , Catálisis , Cetonas/química , Oxigenasas de Función Mixta/genética , Nucleósidos/síntesis química , Tetróxido de Osmio/química , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/genética , Estereoisomerismo
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