RESUMO
Plastic degradation by biological systems with re-utilization of the by-products could be a future solution to the global threat of plastic waste accumulation. Here, we report that the saliva of Galleria mellonella larvae (wax worms) is capable of oxidizing and depolymerizing polyethylene (PE), one of the most produced and sturdy polyolefin-derived plastics. This effect is achieved after a few hours' exposure at room temperature under physiological conditions (neutral pH). The wax worm saliva can overcome the bottleneck step in PE biodegradation, namely the initial oxidation step. Within the saliva, we identify two enzymes, belonging to the phenol oxidase family, that can reproduce the same effect. To the best of our knowledge, these enzymes are the first animal enzymes with this capability, opening the way to potential solutions for plastic waste management through bio-recycling/up-cycling.
Assuntos
Mariposas , Polietileno , Animais , Biodegradação Ambiental , Monofenol Mono-Oxigenase/metabolismo , Mariposas/metabolismo , Plásticos/metabolismo , Polietileno/metabolismo , Saliva/metabolismoRESUMO
An organopalladium chemical dosimeter of Hg(2+) that methylates Hg(2+), undergoing a colour change in 1 : 1 ethanol-water with submicromolar sensitivity, gives rise to an aqua-palladium complex that is methylated by MeHg(+) in the presence of a dithiol compound, undergoing another colour change, thus making the system suitable for the naked-eye detection of Hg(2+) and MeHg(+), two environmentally important species of Hg(2+).
Assuntos
Técnicas de Química Analítica/instrumentação , Compostos Cromogênicos/química , Etanol/química , Mercúrio/análise , Compostos de Metilmercúrio/análise , Paládio/química , Água/química , Cor , Cristalografia por Raios X , Espectroscopia de Ressonância Magnética , Sensibilidade e Especificidade , TitulometriaAssuntos
Antibacterianos/síntese química , Bactérias/efeitos dos fármacos , Isoxazóis/síntese química , Oniocompostos/síntese química , Oxazóis/síntese química , Compostos de Vinila/síntese química , Antibacterianos/farmacologia , Isoxazóis/farmacologia , Testes de Sensibilidade Microbiana , Oniocompostos/farmacologia , Compostos de Vinila/farmacologiaRESUMO
Fast and convenient approaches to the indole nucleus from isocyanides are reviewed as a means for the tailored preparation of conveniently functionalized indoles by using the unique reactivity of isocyanides in one-pot multicomponent and cascade reactions.
RESUMO
We report the synthesis of some new polysulfur-nitrogen heterocyclics by cycloaddition reactions to the thioketo group of readily available tricyclic 1,2-dithiole-3-thiones. Thus treatment of bis[1,2]dithiolo[1,4]thiazine ketothione 1 with diaryl nitrile imines generated from hydrazonoyl chlorides 2a-g gave [1,3,4]thiadiazolylidenyl[1,2]dithiolo[1,4]thiazines 4a-g in high yield. Compounds 4a-f, bearing the same substituents in both aryl groups, were stable but the analogous 4g,h with a p-nitrophenyl group on carbon gave the bis[1,2]dithiolo[1,4]thiazine dione 9, probably by cycloreversion and hydrolysis during chromatography. Treatment of 1, the bis[1,2]dithiolopyrrole ketothione 13, and dithione 12 with ethoxycarbonyl azide 11 gave imines 12 and 15 and bisimine 16, respectively, by an alternative fragmentation of the initial cycloadduct in which the 1,2-dithiole ring is retained. Reaction of 1 with TosMIC gave the imino-1,3-dithietane 17.