Single Image Capture of Bioactive Ion Crosstalk within Inter-Organelle Membrane Contacts at Nanometer Resolution.

Rapid bioactive ion exchange is a form of communication that regulates a wide range of biological processes. Despite advances in super-resolution optical microscopy, visualizing ion exchange remains challenging due to the extremely fast nature of these events. Here, a "converting a dynamic event into a static image construction" (CDtSC) strategy is developed that uses the color transformation of a single dichromatic molecular probe to visualize bioactive ion inter-organelle exchange in live cells. As a proof of concept, a reactive sulfur species (RSS) is analyzed at the mitochondria-lysosome contact sites (MLCs). A non-toxic and sensitive probe based on coumarin-hemicyanine structure is designed that responds to RSS localized in both mitochondria and lysosomes while fluorescing different colors. Using this probe, RSS give-and-take at MLCs is visualized, thus providing the first evidence that RSS is involved in inter-organelle contacts and communication. Taken together, the CDtSC provides a strategy to visualize and analyze rapid inter-organelle ion exchange events in live cells at nanometer resolution.

Intracellular self-assembly based multi-labeling of key viral components: Envelope, capsid and nucleic acids.

Envelope, capsid and nucleic acids are key viral components that are all involved in crucial events during virus infection. Thus simultaneous labeling of these key components is an indispensable prerequisite for monitoring comprehensive virus infection process and dissecting virus infection mechanism. Baculovirus was genetically tagged with biotin on its envelope protein GP64 and enhanced green fluorescent protein (EGFP) on its capsid protein VP39. Spodoptera frugiperda 9 (Sf9) cells were infected by the recombinant baculovirus and subsequently fed with streptavidin-conjugated quantum dots (SA-QDs) and cell-permeable nucleic acids dye SYTO 82. Just by genetic engineering and virus propagation, multi-labeling of envelope, capsid and nucleic acids was spontaneously accomplished during virus inherent self-assembly process, significantly simplifying the labeling process while maintaining virus infectivity. Intracellular dissociation and transportation of all the key viral components, which was barely reported previously, was real-time monitored based on the multi-labeling approach, offering opportunities for deeply understanding virus infection and developing anti-virus treatment.

A Molecular-Imprinted Sensor for Trace Detection of Gibberellin Based on Ferrocenecarboxylic Acid Multiply Marked Dendrimer / 分析化学

A novel strategy employing dendrimer to multi-label the template molecule to improve the sensitivity of molecularly imprinted electrochemical sensor was proposed. The determination relies on a competition reaction between poly ( diethylene-triaminepenta-acetic acid )-glycol ester ( PDTPA )-ferrocene-carboxylic acid ( FcA ) labeled gibberellins acid 3 ( GA3 ) and GA3 in the sample. Since one cavity corresponds with multiple FcA, instead of only one FcA, the intensity of the detecting signal was greatly enhanced, so was the sensitivity of the sensor. Experimental results showed that the molecularly imprinted electrochemical sensor was sensitive to GA3 detection at a concentration from 2. 0í10-9 to 1. 0í10-7 mol/L, with a detection limit of 9. 3í10-10 mol/L. In addition, the sensor had good reproducibility and its feasibility was verified in the analysis of series of real beer samples.