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ABSTRACTThe quinolone resistance crpPgenes can mediate decreased susceptibility to quinolones. However, diversification and prevalence of crpPgenes and crpP-carrying integrative and conjugative elements (ICEs) still need to be elucidated. In this study, genome sequencing was conducted for 200 Chinese Pseudomonas aeruginosaisolates, 16 of which were fully sequenced. All the 37 available CrpP variants were collected for phylogenetic analysis, 10 CrpP enzymes were chosen to conduct cloning and antimicrobial susceptibility test, and 22 crpP-carrying Tn6786-related ICEs were selected for detail genetic dissection analysis. Then, typing/nomenclature schemes for crpPvariants and crpP-carrying ICEs were established for the first time. The 10 representative CrpP enzymes were confirmed to mediate decreased susceptibility to one to three quinolones. Tn6786-related ICEs displayed high-level diversification in both nucleotide sequences and modular structures. Mainly, massive gene acquisition/loss occurred across the whole genomes of Tn6786-related ICEs. 53.5% (107/200) of the tested clinical P. aeruginosaisolates from China carried crpPgenes, which were exclusively located within chromosome-borne Tn6786-related ICEs. The crpP-carrying ICEs were at active stages of evolution and had the high potential to be an important vector for the dissemination of resistance genes besides crpP. The present study furthered the understanding of the bioinformatics and epidemiology of crpPgenes and crpP-carrying ICEs.

•Clonal dissemination of OXA-232-producing Klebsiella pneumoniae(OXA232Kp) in China.•OXA232Kp strains belonged a single subgroup different from others in China.•Genetic dissection of antimicrobial resistance genes and their genetic background.

●Emergence of colistin heteroresistant, hypervirulent and resistant K. pneumoniae.●Exhibited similar survival rate with the hypervirulent control strain ATCC 43816.●The efflux pumps were upregulated in subpopulation compare to the parental strains.●Harboring the hypervirulent genes and pLVPK-like virulence plasmids.

We present soft, layered nanocomposites that exhibit controlled swelling anisotropy and spatially specific shape reconfigurations in response to light irradiation. The use of gold nanoparticles grafted with a temperature-responsive polymer (poly(N-isopropylacrylamide), PNIPAM) with layer-by-layer (LbL) assembly allowed placement of plasmonic structures within specific regions in the film, while exposure to light caused localized material deswelling by a photothermal mechanism. By layering PNIPAM-grafted gold nanoparticles in between nonresponsive polymer stacks, we have achieved zero Poisson’s ratio materials that exhibit reversible, light-induced unidirectional shape changes. In addition, we report rheological properties of these LbL assemblies in their equilibrium swollen states. Moreover, incorporation of dissimilar plasmonic nanostructures (solid gold nanoparticles and nanoshells) within different material strata enabled controlled shrinkage of specific regions of hydrogels at specific excitation wavelengths. The approach is applicable to a wide range of metal nanoparticles and temperature-responsive polymers and affords many advanced build-in options useful in optically manipulated functional devices, including precise control of plasmonic layer thickness, tunability of shape variations to the excitation wavelength, and programmable spatial control of optical response.

We report a combined experimental and theoretical study of micellization of block copolymer with hydrophilic nonionic corona‐forming blocks and weak polyelectrolyte (wPE) core‐forming blocks with pH‐triggered solubility in aqueous solutions. We demonstrate that in addition to micelles with neutral cores, there exist two other types of micelles with PE‐ or ionomer‐like cores, in which monovalent counterions are released or condensed on core wPE block, respectively. The transition between the two types of micelles occurred upon changes in ionization of the PE core block and resulted in nonmonotonous changes of aggregation number as a function of pH. Such micelles with stimulus responsive cores represent promising nanocarriers for controlled delivery applications.

We report on reversible temperature-triggered swelling transitions in hydrogen-bonded multilayer films of a polycarboxylic acid and stimuli-responsive block copolymer micelles (BCMs). A neutral hydrogen-bonding temperature-responsive diblock copolymer, poly(N-vinylpyrrolidone)-b-poly(N-isopropylacrylamide) (PVPON-b-PNIPAM), was synthesized by macromolecular design viathe interchange of xanthates (MADIX). The block copolymer exhibited reversible micellization, forming PNIPAM-core micelles with PVPON coronae in 0.01 M buffer solutions at temperatures higher than 34 °C, or in solutions with high salt concentrations (CNaCl> 0.4 M) at 20 °C. The PVPON-b-PNIPAM BCMs were then assembled with poly(methacrylic acid) (PMAA) at acidic pH and higher temperature using the layer-by-layer (LbL) technique. Within the hydrogen-bonded multilayer, BCMs were stabilized through hydrogen bonding between PVPON and PMAA units and, unlike in solution, did not dissociate into unimers in low-salt solution at T< 34 °C. Instead, PVPON-b-PNIPAM BCMs reversibly swelled within film in response to temperature- or salt-concentration variations, reflecting collapse and dissolution of the BCM PNIPAM cores. The capacity of BCM/PMAA films to retain hydrophobic molecules was also dramatically dependent on temperature and/or ionic strength. The characteristic release time of pyrene from a [BCM/PMAA]10film decreased from 80 to 10 min upon a decrease in temperature from 37 to 20 °C. In addition, at 20 °C, ionic strength was also capable of controlling the collapse of PNIPAM micellar cores and the subsequent film swelling and pyrene release rate. Incorporation of stimuli-responsive BCM micelles within LbL films opens new opportunities in designing nanoscale films capable of controlling molecular swelling, transport, and diffusion in response to environmental stimuli.

The linear-hyperbranched block copolymers, in which the linear polytetrahydrofuran (PTHF) is linked to the apex of hyperbranched poly(phenylene sulfide) (HPPS‐SH), have been synthesized, and the synthesis includes condensation polymerization of 2,4‐dichlorobenzenethiol, subsequent transformation of the resultant HPPS‐SH to HPPS‐OH, and then the cationic ring‐opening polymerization of tetrahydrofuran (THF) using HPPS‐OH as a macrotransfer agent and BF3 · OEt2 as a catalyst. The resultant HPPSs have excellent thermal stability, the PTHF and HPPS chains were decomposed at 361 and 402 °C, respectively. HPPS can be dissolved in THF in the form of aggregates with Rh = 90 nm, which is larger than that (Rh = 55 nm) formed from the corresponding linear PTHF‐HPPS block copolymer.