RESUMEN
This article introduces a novel unlabeled surface-enhanced electrochemiluminescence (SEECL) sensor for malachite green (MG) detection. The SEECL sensor was prepared by modifying the Ru(bpy)32+ doped gold-SiO2 core-shell nanocomposites (Au@SiO2-Ru(bpy)32+) on the gold electrode. Ru(bpy)32+ of nanocomposites can not only emit electrochemiluminescence (ECL) with electrochemical reaction, but also induce the local surface plasmon resonance (LSPR) of gold core. That is beneficial to enhance the ECL signa of sensor. However, in the existence of MG, the luminescence of sensor would be quenched by the fluorescence resonance energy transfer (FRET) between MG and Ru(bpy)32+. In this paper, both fluorescence and ECL of the Au@SiO2-Ru(bpy)32+ were investigated for MG detection. And the results show that the SEECL sensor has high sensitive to MG. Under the optimal experimental conditions, the minimum detection concentration could be achieved about 1.0 nM of MG, which fully meets the China national standard detection requirements of veterinary drug residue in seafood.
RESUMEN
BACKGROUND: Selenium (Se) is a needed trace element for animals and humans. Many fungi have effective mechanisms to acquire, transform and accumulate Se in organic form. In this study, the effects of inorganic Se (sodium selenite) on the medicinal fungus Inonotus hispidus was investigated. RESULTS: Inonotus hispidus was capable of tolerating up to 3.85 mmol L-1 selenite, at which ~85% growth inhibition was seen, with 50% growth inhibition occurring at ~1 mmol L-1 selenite. Growth in 0.29 mmol L-1 Se resulted in I. hispidus mycelium with 115 times higher Se levels compared to growth in standard media, and an organic Se content of 86% to total Se content. The influence of Se accumulation on morphological features of I. hispidus were examined by microscopic and scanning electron microscopic observation. These data revealed significant shrinkage and deformations of I. hispidus hyphae with decreased branching and collapse of clamp connections under higher Se stress. However, conidial production in I. hispidus increased dramatically. The influence of Se on mycelial growth could be recovered by reinoculation in standard media. Se accumulation had only minimal impacts on the yield of the potential selenocompounds such as amino acids, proteins and polysaccharides. By contrast, Se-enriched I. hispidus mycelium was of higher quality due to reduction in crude fat and total ash contents. CONCLUSIONS: These data provide basic and applied information on the feasibility of producing selenized I. hispidus as an enriched and better quality product. © 2021 Society of Chemical Industry.