Generally, the high diversity of protein properties necessitates the development of unique nanoparticle bio-conjugation methods, optimized for each different protein. Here we describe a universal bio-conjugation approach which makes use of a new recombinant fusion protein combining two distinct domains. The N-terminal part is Glutathione S-Transferase (GST) from Schistosoma japonicum, for which we identify and characterize the remarkable ability to bind gold nanoparticles (GNPs) by forming gold–sulfur bonds (Au–S). The C-terminal part of this multi-domain construct is the SpyCatcher from Streptococcus pyogenes, which provides the ability to capture recombinant proteins encoding a SpyTag. Here we show that SpyCatcher can be immobilized covalently on GNPs through GST without the loss of its full functionality. We then show that GST-SpyCatcher activated particles are able to covalently bind a SpyTag modified protein by simple mixing, through the spontaneous formation of an unusual isopeptide bond.

insects of the family Orthoptera: Acrididae including grasshoppers and locust devastate crops and ecosystems around the globe. The effective control of these insects requires large numbers of trained extension agents who try to spot concentrations of the insects on the ground so that they can be destroyed before they take flight. This is a challenging and difficult task. No automatic detection system is yet available to increase scouting productivity, data scale and fidelity. Here we demonstrate MAESTRO, a novel grasshopper detection framework that deploys deep learning within RBG images to detect insects. MAeStRo uses a state-of-the-art two-stage training deep learning approach. the framework can be deployed not only on desktop computers but also on edge devices without internet connection such as smartphones. MAeStRo can gather data using cloud storage for further research and in-depth analysis. In addition, we provide a challenging new open dataset (GHCID) of highly variable grasshopper populations imaged in inner Mongolia. the detection performance of the stationary method and the mobile App are 78 and 49 percent respectively; the stationary method requires around 1000 ms to analyze a single image, whereas the mobile app uses only around 400 ms per image. The algorithms are purely data-driven and can be used for other detection tasks in agriculture (e.g. plant disease detection) and beyond. This system can play a crucial role in the collection and analysis of data to enable more effective control of this critical global pest.

In this work, a joint experimental and theoretical study on the synthetic cannabinoid, 5F-PB-22 (1-(5-fluoropentyl)-8-quinolinyl ester-1H-indole-3-carboxylic acid) is reported. The molecular vibrations of 5F-PB-22 were investigated by Raman and surface-enhanced Raman spectroscopy (SERS) spectroscopies. In parallel, quantum chemical calculations based on density functional theory (DFT) with the hybrid B3LYP exchange-correlation functional coupled with the standard 3-21G basis set were used to determine the geometrical and vibrational characteristics of 5F-PB-22 and to predict the adsorption geometry of the molecule on the silver colloidal surface. The SERS spectrum of 5F-PB-22 was recorded using a 532-nm laser line and a hydroxylamine phosphate reduced silver colloid as the SERS substrate. SERS and Raman spectral bands have been assigned by comparison with the DFT calculated spectrum. A self-aggregation spectrum was obtained, but in order to obtain a spectrum with NaCl as the aggregating agent, a two-step procedure was developed. It was found that 10-mM NaCl can be used as a trigger for aggregation before adding 5F-PB-22followed by the addition of 20-to 100-mM NaCl to complete aggregation. Using this procedure, 5F-PB-22 was easily detected at 2.12 × 10 −8 M. Based on a predicted molecular adsorption geometry from the calculated molecular electrostatic potential and the SERS spectrum, it is proposed that the quinoline moiety of the molecule lies in a preponderant parallel orientation to the silver surface with the plane of the indole ring being perpendicular to the surface.The molecular orientation is affected by the surface coverage by 5F-PB-22 and the presence of Cl − .

An amendment to this paper has been published and can be accessed via a link at the top of the paper.