Multiple cellular events like dynamic actin reorganization and hydrogen peroxide (H2O2) production were demonstrated to be involved in abscisic acid (ABA)-induced stomatal closure. However, the relationship between them as well as the underlying mechanisms remains poorly understood. Here, we showed that H2O2 generation is indispensable for ABA induction of actin reorganization in guard cells of Arabidopsis that requires the presence of ARP2/3 complex. H2O2-induced stomatal closure was delayed in the mutants of arpc4 and arpc5, and the rate of actin reorganization was slowed down in arpc4 and arpc5 in response to H2O2, suggesting that ARP2/3-mediated actin nucleation is required for H2O2-induced actin cytoskeleton remodelling. Furthermore, the expression of H2O2 biosynthetic related gene AtrbohD and the accumulation of H2O2 was delayed in response to ABA in arpc4 and arpc5, demonstrating that misregulated actin dynamics affects H2O2 production upon ABA treatment. These results support a possible causal relation between the production of H2O2 and actin dynamics in ABA-mediated guard cell signalling: ABA triggers H2O2 generation that causes the reorganization of the actin cytoskeleton partially mediated by ARP2/3 complex, and ARP2/3 complex-mediated actin dynamics may feedback regulate H2O2 production.

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Mesoporous aluminosilicates (MAs) with high hydrothermal stability had been synthesized via assembly of typical microporous zeolite Y precursors. However, the high consumption amount of the P123 template and water is still an obstacle to its industrial application. Synthesis of hydrothermally stable mesoporous aluminosilicates (MAs) in a high-concentration-template solution is a promising strategy to decrease the consumption amount of organic template and water. A means to prevent the clumping of micelles in the high-concentration system is of vital importance in the synthesis of MAs. In the present investigation, the goal was achieved by the introduction of a cotemplate with a high hydrophilic−lipophilic balance (HLB) value into F68 micelles. The effect of a cotemplate with different HLBs on the physicochemical properties of MA products was investigated. Compared with cotemplate sodium dodecyl dimethylbenzene sulfonate (SDMBS) of HLB 9.7 and fatty alcohol polyoxyethylene ether-9 (AEO-9) of HLB 13.5, octyl phenol polyoxyethylene ether-10 (OP-10) of HLB 14.1 favored the formation of well-crystallized MAs with maximum integrated intensity, surface area, and hydrothermal stability. The improvement of physicochemical properties could be attributed to the increase in overall hydrophilicity of composite micelles. As a result of this, well-ordered MAs were obtained with greatly decreased consumption of F68 and water.

Targeted drug delivery with minor off-target effects is urgently needed for precise cancer treatments. Here, a sequentially triggered strategy based on double targeting elements is designed to meet this purpose. By using an acidic pH-responsive i-motif DNA and a tumor cell-specific aptamer as targeting elements, a smart dual-targeted DNA nanocapsule (ZBI5-DOX) was constructed. ZBI5-DOX can be firstly triggered by acidic pH, and then bind to target cells via aptamer recognition and thus targeted release of the carried DOX chemotherapeutics. With this smart DNA nanocapsule, the carried DOX could be precisely delivered to target SMMC-7721 tumor cells in acidic conditions. After drug treatments, selective cytotoxicity of the DNA nanocapsule was successfully achieved. Meanwhile, the DNA nanocapsule had a specific inhibition effect on target cell migration and invasion. Therefore, this sequentially triggered strategy may provide deep insight into the next generation of targeted drug delivery.

Abstract.A new kind of biocompatible probe (PEG-TPEFE) with aggregation-induced emission (AIE) characteristic was reported, which was synthesized from fluorene, tetraphenylethylene (TPE) and polyethylene glycol monomethyle ether 1000 (PEG 1000 ). PEG-TPEFE can aggregate into nanosphere and emit strong blue fluorescence in aqueous media. Cytotoxicity assay reveals low cytotoxicity and excellent biocompatibility of this nanoprobe. This nanoprobe was internalized and accumulated by live cells and shown high photostability.