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Genetic transformation is a valuable and essential method that provides powerful insights into the gene function of microorganisms and contributes to the construction of engineered bacteria. Here, we developed a novel genetic transformation system to easily knock out a highly GC‐rich gene (74.71% GC) from Burkholderia pyrrocinia JK‐SH007, a biocontrol strain of poplar canker disease. This system revealed a reliable selectable marker (trimethoprim resistance gene, Tmp) and a simplified, efficient transformation method (6,363.64 CFU/μg, pHKT2) that was developed via freeze‐thawing. The knockout recombineering of B. pyrrocinia JK‐SH007 was achieved through a suicide plasmid with a three‐fragment mutagenesis construct. The three‐fragment cassette for mutagenesis was generated by overlap extension and touchdown PCRs and composed of Tmp flanked by GC‐rich upstream and downstream fragments from B. pyrrocinia JK‐SH007. The mutant strain (ΔBpEG), which was verified by PCR, lost 93.3% of its ability to degrade carboxymethyl cellulose over 40 days. Overall, this system may contribute to future research on B. pyrrocinia traits., A novel genetic transformation system was developed to easily knock out a highly GC‐rich gene (74.7% GC) from Burkholderia pyrrocinia JK‐SH007 by homologous recombination with freeze‐thawing transformation.

We evaluate the validity of a projection-based test checking linear models when the number of covariates tends to infinity, and analyze two gene expression datasets. We show that the test is still consistent and derive the asymptotic distributions under the null and alternative hypotheses. The asymptotic properties are almost the same as those when the number of covariates is fixed as long as p/n → 0 with additional mild assumptions. The test dramatically gains dimension reduction, and its numerical performance is remarkable.

Aims and objectives We explored dispatched nurses’ experiences of wearing full gear personal protective equipment to care for patients with coronavirus disease‐2019 (COVID‐19) in Wuhan, China. Background Full gear personal protective equipment is the primary and foremost measure to prevent the contact and transmission of severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV2); however, working in full gear personal protective equipment may hinder nursing care activities and thus negatively affect patients’ and nurses’ health. Design This descriptive qualitative inquiry followed the COREQ guidelines. Methods Individual semi‐structured telephone interviews were conducted in a purposive sample of 15 frontline nurses who were dispatched to the outbreak epicentre from March to April 2020. Verbatim transcripts were content analysed. Results Four themes emerged from the data: inadequate preparedness for working with full gear personal protective equipment, full gear personal protective equipment stimulated stress responses, coping strategies and professional growth. Participants learned a great deal from problem‐focussed and emotion‐focussed strategies to tackle challenges related to the prolonged wearing of full gear personal protective equipment for quality nursing care and reduced risk of exposure. They became more vigilant to the adherence to evolving protocols and appropriate training concerning full gear personal protective equipment use. Conclusions Frontline nurses confronted various but diminishing challenges related to the use of full gear personal protective equipment when caring for patients with COVID‐19 across the approximate 40‐day period. Consistent use of coverall personal protective equipment to protect from SARS‐CoV‐2 in high exposure settings would be feasible if nurses were better prepared; therefore, scenario‐based skill training concerning the prolonged use of full gear personal protective equipment should be offered regularly and intensively. Relevance to clinical practice This study informs future decisions concerning improved full gear personal protective equipment‐related psychomotor training and promoting ways for nurses to cope with the stress that comes from working in highly contiguous environments.

Metal oxide nanoparticles and carbon nanoparticles, as common nanoparticles (NPs), can cause autophagy in certain cells, which will lead to biohealth risk issues. This study determined the difference in autophagy induced by zinc oxide nanoparticles (ZnO NPs) and single-walled carbon nanotubes (SWCNTs) in respiratory epithelial cells. ICP-OES results showed that NPs uptake as well as the intercellular contents of particles affected cytotoxicity in a dose-dependent manner. ZnO NPs-30 nm had a distinct green dot structure representing autophagy, the SWCNTs exposure group had a few green light spots at a concentration of 10 μg/L. The ROS content of the ZnO NP-30 nm exposure group had the greatest increase at a concentration of 1000 μg/L, which was 2.5 times higher than that of the control, the SWCNTs exposure group showed a 2.2-fold increase. A slight downregulation of p-mTOR was detected, and the ZnO NPs-30 nm treatment group had the significant downregulation rate. The gene and protein expression levels of Beclin-1 and LC3B were upregulated as the exposure concentration increased. The protein expression of Beclin-1 and LC3B in the 1000 μg/L ZnO NPs-30 nm exposure group were 5.21 times and 4.12 times that of the control, respectively. The mRNA expression of Beclin-1 and LC3B in the 1000 μg/L ZnO NPs-30 nm exposure group were 5.04 times and 3.61 times that of the control, respectively. At any concentration, the effect of ZnO NPs-30 nm was greater than that of the SWCNTs. Interaction and crosstalk analysis showed that exposure to ZnO NPs-30 nm caused autophagy through the aggregation of undegraded autophagosomes, whereas SWCNTs exposure induced diminished intercellular oxidative stress to inhibit autophagy. Therefore, this study demonstrated that the effects of autophagy induced by ZnO NPs-30 nm and SWCNTs were different. The health risks of ZnO-30 nm NPs are higher than those of SWCNTs.

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Intracellular protein degradation is essential for the survival of all organisms, but its role in interspecies interaction is unknown. Here, we show that the ClpXP protease of Pseudomonas aeruginosa suppresses its antimicrobial activity against Staphylococcus aureus, a common pathogen co-isolated with P. aeruginosa from polymicrobial human infections. Using proteomic, biochemical, and molecular genetic approaches, we found that this effect is due to the inhibitory effects of ClpXP on the quorum sensing (QS) of P. aeruginosa, mainly by degrading proteins (e.g., PhnA, PhnB, PqsR, and RhlI) which are critical for the production of QS signal molecules PQS and C4-HSL. We provide evidence that co-culturing with S. aureus induces a decrease in the activity of ClpXP in P. aeruginosa, an effect which was also achieved by the treatment of P. aeruginosa with N-acetylglucosamine (GlcNAc), a widespread chemical present on the surface of diverse cell types from bacteria to humans. These findings extend the range of biological events governed by proteolytic machinery to microbial community structure, thus also suggesting that a chemical-induced alteration of protein homeostasis is a mechanism for interspecies interactions.

Atrial fibrillation (AF) affects 33.5 million individuals worldwide. It accounts for 15% of strokes and increases risk of heart failure and sudden death. The voltage-gated cardiac sodium channel complex is responsible for the generation and conduction of the cardiac action potential, and composed of the main pore-forming α-subunit Na(v)1.5 (encoded by the SCN5A gene) and one or more auxiliary β-subunits, including Na(v)β1 to Na(v)β4 encoded by SCN1B to SCN4B, respectively. We and others identified loss-of-function mutations in SCN1B and SCN2B and dominant-negative mutations in SCN3B in patients with AF. Three missense variants in SCN4B were identified in sporadic AF patients and small nuclear families; however, the association between SCN4B variants and AF remains to be further defined. In this study, we performed mutational analysis in SCN4B using a panel of 477 AF patients, and identified one nonsynonymous genomic variant p.Gly8Ser in four patients. To assess the association between the p.Gly8Ser variant and AF, we carried out case-control association studies with two independent populations (944 AF patients vs. 9,81 non-AF controls in the first discovery population and 732 cases and 1,291 controls in the second replication population). Significant association was identified in the two independent populations and in the combined population (p = 4.16 × 10(−4), odds ratio [OR] = 3.14) between p.Gly8Ser and common AF as well as lone AF (p = 0.018, OR = 2.85). These data suggest that rare variant p.Gly8Ser of SCN4B confers a significant risk of AF, and SCN4B is a candidate susceptibility gene for AF.

As the last resort for intractable Gram-positive bacterial infections, vancomycin is losing efficacy with the emergence of vancomycin-resistant bacteria, especially vancomycin-resistant Enterococci (VRE). To combat this threat, we rationally designed and synthesized 39 novel vancomycin derivatives by respective or combined modifications using metal-chelating, lipophilic, and galactose-attachment strategies for extensive structure-activity relationship (SAR) analysis. In a proposed mechanism, the conjugation of dipicolylamine on the seventh amino acid resorcinol position or C-terminus endowed the vancomycin backbone with binding capacity for the pyrophosphate moiety in lipid II while maintaining the intrinsic binding affinity for the dipeptide terminus of the bacterial cell wall peptidoglycan precursor. The in vitro antibacterial activities were evaluated, and the optimal compounds indicated 16- to 1024-fold higher activity against VRE than that of vancomycin. Compound 11 b (3',5'-bis(dipicolylaminomethyl)tyrosine [1,2,3]triazolylmethoxylethyoxyl ethylaminomethyl-N-decylvancomycin) was found to have particularly potent activity against VRE through synergistic effects brought about by combining two peripheral modifications.

Series of glassy and glass-ceramic samples in the GeSe2–Ga2Se3–NaI system is prepared by melt-quenching technique and the glass-forming region is well-defined by XRD investigations. Na-ion conduction behavior is systemically studied by impedance measurements. For the glasses in the series (100−2x)GeSe2–xGa2Se3–xNaI, ionic conductivities increased with increasing x, whereas the attributed activation energy of ion conduction decreases. The enhanced mechanism is discussed by employing Raman spectra. In addition, the effect of the crystal phases NaI and Ga2Se3 on the ionic conduction behavior in the (70−x)GeSe2–xGa2Se3–30NaI samples is discussed. Although it shows that the poorly conducting crystallites of NaI and Ga2Se3 have a negative effect on the ionic conductivities in this series, the highest ionic conductivity of 1.65 × 10−6 S/cm is obtained in the 45GeSe2–25Ga2Se3–30NaI glass. Finally, this study also demonstrates a possible way to search appropriate Na-ion solid electrolytes for all-solid-state batteries.

Rhamnolipid acts as a virulence factor during Pseudomonas aeruginosa infection. Here, we show that deletion of the catabolite repression control (crc) gene in P.aeruginosa leads to a rhamnolipid-negative phenotype. This effect is mediated by the down-regulation of rhl quorum sensing (QS). We discover that a disruption of the gene encoding the Lon protease entirely offsets the effect of crc deletion on the production of both rhamnolipid and rhlQS signal C4-HSL. Crc is unable to bind lon mRNAin vitro in the absence of the RNA chaperon Hfq, while Crc contributes to Hfq-mediated repression of the lon gene expression at a posttranscriptional level. Deletion of crc, which results in up-regulation of lon, significantly reduces the in vivo stability and abundance of the RhlI protein that synthesizes C4-HSL, causing the attenuation of rhlQS. Lon is also capable of degrading the RhlI protein in vitro. In addition, constitutive expression of rhlI suppresses the defects of the crc deletion mutant in rhamnolipid, C4-HSL and virulence on lettuce leaves. This study therefore uncovers a novel posttranscriptional regulatory cascade, Crc-Hfq/Lon/RhlI, for the regulation of rhamnolipid production and rhlQS in P.aeruginosa.

The prognostic value of IDH1 mutations has been systematically evaluated in acute myeloid leukemia (AML) patients recently. However, the role of IDH1 expression in AML is still under exploration. To investigate the clinical significance, we analyzed the IDH1/2 expression in 320 patients with cytogenetically normal AML (CN-AML) by quantitative real-time reverse-transcription polymerase chain reaction. High expression of IDH1 was predominant in patients with FLT3-ITD and DNMT3A mutations and less prevalent in cases with CEBPA double allele mutations. Strong association was observed between high IDH1 expression and low expression of microRNA 181 family. Prognosis was adversely affected by high IDH1 expression, with shorter overall survival and event-free survival in the context of clinical characteristics, including age, WBC count, and gene mutations of NPM1, FLT3-ITD, CEBPA, IDH1, IDH2 and DNMT3A in CN-AML. Moreover, the clinical outcome of IDH1 expression in terms of overall survival, event-free survival and complete remission rate still remained in multivariate models in CN-AML. Importantly, the prognostic value was validated using the published microarray data from 79 adult patients treated according to the German AMLCG-1999 protocol. Our results demonstrated that high IDH1 expression is associated with a poor prognosis of CN-AML.

Poly(2,3-dimethylaniline)/TiO2 composite (PTC) was prepared by emulsion polymerization using dodecyl benzene sulfonic acid as emulsifier and dopant. The structure of PTC was characterized by Fourier transformation infrared spectroscopy, wide-angle X-ray diffraction, and field emission scanning electron microscopy. Effect of TiO2 content on the PTC properties was studied by tafel polarization curves, electrochemical impedance spectroscopy, polymerization yield, and cyclic voltammetry measurements. The results showed that the anticorrosion property and electrochemical activity of PTC reached a maximum level when the content of TiO2 was 15%. Epoxy coatings containing poly(2,3-dimethylaniline) (P(2,3-DMA)) and PTC, respectively, were painted on steel and accelerated electrochemical corrosion tests were performed to evaluate the anticorrosion property of the coatings in 3.5% NaCl solution. The results showed that the PTC coating had higher corrosion resistance than that of P(2,3-DMA). POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers

Polyaniline (PANI) nanofibers were prepared via the reaction of aniline with ammonium persulfate carried out in ethylene glycol (EG) medium without water. These purified PANI nanofibers could be dispersed in water and other polar solvents, such as ethanol, EG, and N,N-dimethylformamide, to form colloids. The morphology and structure of the PANI nanofibers were characterized and the effects of mechanical stirring on the morphology, structure, and electrical performance of PANI were investigated. The results indicated that the intermolecular H-bonding interaction between molecules of PANI and alcohol is advantageous to the one-dimensional growth of PANI, and a stirring reaction results in a lager size, a higher doping level, conductivity, degree of crystallinity, and oxidation than a nonstirring reaction. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers.

The glycolysis of poly(ethylene terephthalate) (PET) was carried out using excess ethylene glycol (EG) in the presence of zinc acetate as catalysts under microwave irradiation. The effects of particle size, microwave power, the weight ratio of EG to PET, the weight ratio of catalyst to PET, reaction temperature and stirring speed on the yield of bis(hydroxyethyl terephthalate)(BHET) were investigated. The experimental results indicated that the glycolysis rate was significantly influenced by stirring speed and initial particle size. The optimal parameters of glycolysis reactions were the weight ratio of catalyst to PET of 1%, the weight ratio of EG to PET of 5, 500 W and 196°C, the yield of BHET reached to 78% at only 35 min. The glycolysis products were analyzed and identified by FTIR, differential scanning calorimetry, and elemental analysis. The kinetics of glycolysis of PET under microwave irradiation could be interpreted by the shrinking core model of the film diffusion control. The apparent activation energy was evaluated using the Arrhenius equation and it was found to be 36.5 KJ/mol, which was lower compared to the same process using conventional heating. The experimental results also showed that the reaction time was significantly decreased under microwave irradiation as compared with it by conventional heating. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

54GeS2–36Sb2S3–10In2S3 glass-ceramics were prepared by heat-treating the base glass above Tg for different durations. The results of Raman spectra and XRD patterns show that the first precipitated crystals during the heat treatment are In2S3 and the crystallization of the Sb2S3 and GeS2 subsequently occurs. Bulk samples heat-treated at 295°C for different heating rates and durations are used to study the crystallization mechanism and evolution of the three crystallization peaks (CPs). It is found that three CPs partly overlap with each other and then separate with increasing heat-treating durations.

In this research, glycolysis of poly(ethylene terephthalate) (PET) with ethylene glycol (EG) was carried out using Zn/Al mixed oxide catalyst. These mixed oxides were prepared by calcining crystalline Zn/Al hydrotalcites at different calcination temperatures. The samples and corresponding precursors were characterized by X-ray diffraction, BET, Fourier-transform infrared spectra, thermogravimetry/differential thermal analysis, and Hammett titration method. The experimental results showed that Zn/Al mixed oxides obtained from hydrotalcites were found to be more active than their individual oxides for glycolysis of PET. The relationship between catalytic performance and chemical–physical features of catalysts was established. In addition, a study for optimizing the glycolysis reaction conditions, such as the weight ratio of EG to PET, catalyst amount and reaction time, was performed. The conversion of PET and yield of bis(2-hydroxyethyl terephthalate) (BHET) reached about 92% and 79%, respectively, under the optimal experimental conditions. Moreover, it should be noted that Zn/Al mixed oxide not only provided an effective heterogeneous catalyst for glycolysis of poly(ethylene terephthalate), but also presented a novel method for decolorization of discarded colored polyester fabric. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41053.