A biomimetic sensor for the determination of dipyrone was prepared by modifying carbon paste with cobalt phthalocyanine (CoPc), and used as an amperometric detector in a flow injection analysis (FIA) system. The results of cyclic voltammetry experiments suggested that CoPc behaved as a biomimetic catalyst in the electrocatalytic oxidation of dipyrone, which involved the transfer of one electron. The optimized FIA procedure employed a flow rate of 1.5 mL min(-1), a 75 μL sample loop, a 0.1 mol L(-1) phosphate buffer carrier solution at pH 7.0 and amperometric detection at a potential of 0.3 V vs. Ag/AgCl. Under these conditions, the proposed method showed a linear response for dipyrone concentrations in the range 5.0 × 10(-6)-6.3 × 10(-3) mol L(-1). Selectivity and interference studies were carried out in order to validate the system for use with pharmaceutical and environmental samples. In addition to being environmentally friendly, the proposed method is a sensitive and selective analytical tool for the determination of dipyrone.
Here, we report that the Neurospora crassa FLB-3 protein, the ortholog of the Aspergillus nidulans FlbC transcription factor, is required for developmental control. Deletion of flb-3 leads to changes in hyphae morphology and affects sexual and asexual development. We identified, as putative FLB-3 targets, the N. crassa aba-1, wet-1 and vos-1 genes, orthologs of the ones involved in A. nidulans asexual development and that work downstream of FlbC (abaA, wetA and vosA). In N. crassa, these three genes require FLB-3 for proper expression; however, they appear not to be required for normal development, as demonstrated by gene expression analyses during vegetative growth and asexual development. Moreover, mutant strains in the three genes conidiate well and produce viable conidia. We also determined FLB-3 DNA-binding preferences via protein-binding microarrays (PBMs) and demonstrated by chromatin immunoprecipitation (ChIP) that FLB-3 binds the aba-1, wet-1 and vos-1 promoters. Our data support an important role for FLB-3 in N. crassa development and highlight differences between the regulatory pathways controlled by this transcription factor in different fungal species.
A construção e a aplicação de um sensor biomimético para a determinação de 4-metilbenzilideno cânfora (4-MBC), um protetor de radiação ultravioleta (UV), são descritas. O sensor foi preparado pela modificação de um eletrodo de pasta de carbono com um complexo de cloreto de ferro(III) com ftalocianina, FePcCl. As medidas amperométricas conduzidas com o sensor, sob um potencial aplicado de 0,0 V vs. Ag|AgCl em uma mistura de tetraidrofurano e 0,1 mol L -1 H 2 SO 4 (30:70 em volume), mostraram uma resposta linear no intervalo de 1,8×10 -4 to 9,0×10 -4 mol L -1 . Uma investigação detalhada da seletividade da resposta frente a outros nove filtros UV também foi realizada. Um mecanismo de resposta do sensor foi proposto e os resultados para a quantificação de 4-MBC em protetores solares comerciais e em águas de piscinas e de rios são apresentados.The construction and application of a biomimetic sensor for determination of 4-methylbenzylidene camphor (4-MBC), an ultraviolet (UV) radiation protector, are described. The sensor was prepared by modifying a carbon paste electrode with iron(III) phthalocyanine chloride (FePcCl). Amperometric measurements carried out with the sensor under an applied potential of 0.0 V vs. Ag|AgCl in a mixture of tetrahydrofuran and 0.1 mol L -1 H 2 SO 4 solution (30:70 volume ratio) showed a linear response range from 1.8×10 -4 to 9.0×10 -4 mol L -1 . A detailed selectivity investigation for other nine UV filters was also performed. A sensor response mechanism was proposed and the results for 4-MBC quantification in commercial sunscreens and in water from swimming pools and rivers are presented.Keywords: iron phthalocyanine, amperometric sensor, methylbenzylidene camphor IntroductionChemical ultraviolet (UV) filters have been introduced in 1889, when an acidified quinine sulfate solution was used to block UV radiation, 1 and thereafter sunscreen has become an everyday cosmetic with continuously increasing use.The positive effect exerted by UV filters is to block the UV light radiation damage from sunlight, sunlamps and in tanning parlours; moreover, they have color protective abilities and therefore may prevent premature fading of hair color and damage to hair cuticle. On the other hand, it has been recently reported that commonly used chemical UV filters may cause endocrine disrupting effects in both aquatic and terrestrial animals, as well as in human skin cells. [1][2][3][4] In addition, five of the most commonly UV filters used in cosmetic formulations, i.e., oxybenzone, octyl methoxycinnamate (OMC), homosalate, p-aminobenzoic acid (PABA), octyldimethyl-PABA (ODP), and 4-methylbenzylidene camphor (4-MBC), exhibited oestrogenic effects in MCF-7 (Michigan Application of a Biomimetic Sensor Based on Iron Phthalocyanine Chloride J. Braz. Chem. Soc. 1378 Cancer Foundation-7) breast cancer cells. Furthermore, oxybenzone, 4-MBC and OMC were confirmed to be oestrogenic by classical in vivo uterotrophic assays with rats dosed in the feed. For the most potent oestrogenic UV filter 4-MBC, the eff...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.