Bright and sensitive red voltage indicators for imaging action potentials in brain slices and pancreatic islets.

Genetically encoded voltage indicators (GEVIs) allow the direct visualization of cellular membrane potential at the millisecond time scale. Among these, red-emitting GEVIs have been reported to support multichannel recordings and manipulation of cellular activities with reduced autofluorescence background. However, the limited sensitivity and dimness of existing red GEVIs have restricted their applications in neuroscience. Here, we report a pair of red-shifted opsin-based GEVIs, Cepheid1b and Cepheid1s, with improved dynamic range, brightness, and photostability. The improved dynamic range is achieved by a rational design to raise the electrochromic Förster resonance energy transfer efficiency, and the higher brightness and photostability are approached with separately engineered red fluorescent proteins. With Cepheid1 indicators, we recorded complex firings and subthreshold activities of neurons on acute brain slices and observed heterogeneity in the voltage­calcium coupling on pancreatic islets. Overall, Cepheid1 indicators provide a strong tool to investigate excitable cells in various sophisticated biological systems.

A tool kit of highly selective and sensitive genetically encoded neuropeptide sensors.

Neuropeptides are key signaling molecules in the endocrine and nervous systems that regulate many critical physiological processes. Understanding the functions of neuropeptides in vivo requires the ability to monitor their dynamics with high specificity, sensitivity, and spatiotemporal resolution. However, this has been hindered by the lack of direct, sensitive, and noninvasive tools. We developed a series of GRAB (G protein-coupled receptor activation‒based) sensors for detecting somatostatin (SST), corticotropin-releasing factor (CRF), cholecystokinin (CCK), neuropeptide Y (NPY), neurotensin (NTS), and vasoactive intestinal peptide (VIP). These fluorescent sensors, which enable detection of specific neuropeptide binding at nanomolar concentrations, establish a robust tool kit for studying the release, function, and regulation of neuropeptides under both physiological and pathophysiological conditions.

Assessing environmental impact of NOX and SO2 emissions in textiles production with chemical footprint.

Air pollution is a major concern of the new civilized world due to its adverse impact on human health and environment. As typical air pollutants, nitrogen oxide (NOX) and sulfur dioxide (SO2) not only pollute the atmosphere by forming acid rain and particulate matter, but are also harmful to the human respiratory system. Significant emissions of NOX and SO2 in the production phases make the textile industry under enormous environmental pressure. Chemical footprint (ChF) is an effective method for transforming the potential environmental risks of pollutant emissions into an intuitive form of toxicity. In this study, we present a ChF assessment method for NOX and SO2 emissions from textiles production. For this purpose, we adopt the USEtox model and calculate the relevant characterization factors (CFs) by considering the physicochemical properties and toxicity of NOX and SO2. The textile industry in Zhejiang Province, China, is chosen as a case study to demonstrate the feasibility of this proposed ChF assessment methodology. Results indicate that ChF caused by NOX emission in Zhejiang's textile industry is approximately eight times larger than that caused by SO2 emission. The four sub-sectors of Zhejiang's textile industry (textile manufacturing sector; textile wearing apparel, footware, and caps manufacturing sector; leather, fur, feather and related products manufacturing sector; chemical fibers manufacturing sector) also have similar proportional distributions of ChFs. Besides, the textile manufacturing sector has the largest ChF, accounting for 73% of the total ChF caused by NOX and SO2 emissions.