In this work, a novel ratiometric fluorescent nanosensor by coupling mesoporous silica spheres-coated nitrogen-doped carbon dots (N-CDs@SiO 2 ) and bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs) was developed for sensitive detection of glyphosate. BSA-AuNCs nanocomposites were covalently connected onto the surface of amino-functionalized N-CDs@SiO 2 nanospheres, causing the core-satellite probes with two fluorescence emissions at 436 and 651 nm, respectively, under a single excitation of 360 nm. The N-CDs@SiO 2 @BSA-AuNCs "signal on−off−on" ratiometric fluorescent probes could realize highly selective differentiation and accurate detection of glyphosate based on the fluorescence quenching of Cu 2+ on BSA-AuNCs and glyphosate-induced fluorescence recovery due to the strong complexation of glyphosate toward Cu 2+ . The developed ratiometric fluorescent nanosensor exhibited excellent selectivity to glyphosate, wide detectability in a concentration range of 5−100 ng/mL, high sensitivity with a low detection limit of 3.4 ng/mL, as well as fascinating reliability and practicability in real malt samples with recoveries of 94.81−101.61%. This study provides a universal platform for versatile sensing of more trace analytes in complex matrices and can be extended for wide application in the environment and food safety fields.

Accurate abundance estimation of species is essential for metagenomic analysis. Although many methods have been developed for classification of metagenomic data and abundance estimation of species, the abundance estimation of species remains challenging due to the ambiguous reads that align equally well to more than one genome. Here, we present Centrifuge+, which introduces unique mapping rate to describe the influence of similarities among species in the reference database when analyzing ambiguous reads. In contrast to the popular Centrifuge, Centrifuge+ improved the accuracy of abundance estimation on simulated reads from 4278 complete prokaryotic genomes.