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Burkholderia pseudomallei is the etiological agent of melioidosis, which is an emerging infectious disease endemic to many tropical regions. Autophagy is an intrinsic cellular process that degrades cytoplasmic components and plays an important role in protecting the host against pathogens. Like many intracellular pathogens, B. pseudomallei can evade the autophagy-dependent cellular clearance. However, the underlying mechanism remains unclear. In this study, we applied a combination of multiple assays to monitor autophagy processes and found that B. pseudomallei induced an incomplete autophagic flux and eliminate autophagy clearance in macrophages by blocking autophagosome-lysosome fusion. Based on a high-throughput microarray screening, we found that LIPA (lysosomal acid LIPAse A) was downregulated during B. pseudomallei infection. MiR-146a was then identified to be specifically upregulated upon infection with B. pseudomallei and further regulated LIPA expression by interacting with 3'UTR of LIPA. Furthermore, overexpression of miR-146a contributed to the defect of autophagic flux caused by B. pseudomallei and was beneficial for the survival of B. pseudomallei in macrophages. Therefore, our findings suggest that miR-146a inhibits autophagy via posttranscriptional suppression of LIPA expression to maintain B. pseudomallei survival in macrophages.

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Here, PEI@PMMA microspheres were prepared by grafting polyethyleneimine (PEI) on poly(methyl methacrylate) (PMMA) magnetic microspheres and successfully used to immobilize lipase. The results showed that PEI@PMMA microspheres had strongly adsorbed lipase (49.1 mg/g microsphere) via electrostatic attraction. To prevent lipase shedding, the adsorbed lipase was further crosslinked with PEI on microspheres using glutaraldehyde as crosslinker. Consequently, PEI-crosslinked lipase (2.14 U/mg) exhibited 2.6 times and 1.4 times higher activity respectively than the directly covalent lipase (0.82 U/mg) and the crosslinked lipase aggregates (1.57 U/mg), which was close to the activity of adsorbed lipase (2.20 U/mg). Conformational analysis from FTIR spectroscopy showed that PEI-crosslinked lipase retained its natural structure well. And the α-helix structure seemed to play a key role in enhancing lipase activity. Furthermore, the effects of various parameters on crosslinking reaction were investigated. Also, PEI-crosslinked lipase revealed higher pH and thermal stability. The Michaelis constant (Km) was increased and the optimum temperature of lipase was widened observably after crosslinking with PEI on PEI@PMMA magnetic microspheres.

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As a new type of porous material, metal-organic frameworks (MOFs) have been widely studied in gas adsorption and separation, especially in C2 hydrocarbons. Considering the stronger interaction between the unsaturated molecules and the metal sites, and the smaller molecular size of unsaturated molecules, the usual relationship of affinities and adsorption capacities among C2 hydrocarbons in most common MOFs is C2H2 > C2H4 > C2H6. Herein, a unique microporous metal-organic framework, NUM-7a (activated NUM-7), with a completely reversed adsorption relationship for C2 hydrocarbons (C2H6 > C2H4 > C2H2) has been successfully synthesized, which breaks the traditional concept of the adsorption relationship of MOFs for C2 hydrocarbons. Based on this unique adsorption relationship, a green and simple one-step separation purification for a large amount of C2H4 can be expected to be achieved through the selective adsorption of C2H6. In addition, NUM-7a also shows good selectivities in C2H2/CO2 and CO2/CH4.

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Two luminescent coordination polymers (CPs), {[Cd2L2(H2O)4]·H2O}n (1) and {[Zn2L2(H2O)4]·H2O}n (2) (H2L = 5-(1H-1,2,4-triazol-1-yl)isophthalic acid) are reported herein. The CPs reveal readily dispersible two-dimensional (2D) layer structures with considerable stability in aqueous media within a wide pH range (pH = 2-12). Sensing experiments indicate that they can serve as highly selective and sensitive fluorescent probes toward CrVI-anions (CrO42- and Cr2O72-).

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A novel metal-organic framework, ZJU-196, with extraordinary acid-base resistant stability has been successfully synthesized, exhibiting highly efficient separation of acetylene from C2H2/CO2 mixtures under ambient conditions.