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1.
Artigo em Inglês | MEDLINE | ID: mdl-33392689

RESUMO

In this paper, the 36 topsoil (0-10 cm) samples were collected and the contents of Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb were analyzed. The results indicated that the contents of Cu and As in all samples exceeded the soil background values of Anhui province, while the Co and Pb contents were lower than the background values. Geo-statistics and positive matrix factorization were applied to identify the sources of soil heavy metals, which were nature factor (15.7%), industrial activities (21.2%), coal mine (50.9%) and traffic emission (12.2%), respectively. The calculation results of health risk model based on positive matrix factorization model showed that coal mine activities accounted for the largest proportion of total source contribution, followed by industrial activities. In addition, compared with adults, the trend of health risk of children from four sources in three lands were same as adults, but their health risk was higher than adults.

2.
Nanotechnology ; 2020 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-33361573

RESUMO

Precise control of structure and bonds in doped carbon dots (CDs) is siginificant to tune their fluorescence as desired. Up to now, it still lacks effective ways to control the bonds of doped CDs. In this article, we showed that the fluorescence of B/N-doped carbon dots (B/N-CDs) could be precisely tuned just by controlling precursor pH values. As-prepared B/N-CDs exhibit two emission bands, including one emission peak around 450 nm from the defect state from low sp2 hybridization of carbon atoms as well as the other emission peak around 360nm from the B-N bond. The results of the ratio of the maximum intensity of the two emission peaks above show a linear relationship. Meanwhile, the role of pH value of precursor on the luminescence of B/N-CDs is deeply studied. On the one hand, the pH value affects the bonding process of CDs. N-H bonds tend to form at a low pH value while more competitive of B-N bonds exist at much higher pH value, leading to the pH-dependent intensity for 360nm emission band. On the other hand, a high pH value will cause higher crystallinity, thus suppressing the defect state fluorescence at 450nm.The dual effects of pH lead to precisely controlled dual emission intensities as well as ratiometric fluorescence.

3.
Tree Physiol ; 2020 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-33367887

RESUMO

Fruit semi-russeting is an undesirable quality trait that occurs in fruit production. It is reported that preharvest fruit bagging could effectively alleviate fruit exocarp semi-russeting, but the physiological and molecular mechanisms remain unclear. In the present study, we performed an in-depth investigation into pear fruit semi-russeting from morphologic, metabolic and transcriptomic perspectives by comparing control (semi-russeted) and bagged (non-russeted) 'Cuiguan' pear fruits. The results showed that significant changes in cutin and suberin resulted in pear fruit semi-russeting. Compared with the skin of bagged fruits, the skin of the control fruits presented reduced cutin contents accompanied by an accumulation of suberin, which resulted in fruit semi-russeting; α, ω-dicarboxylic acids accounted for the largest proportion of typical suberin monomers. Moreover, combined transcriptomic and metabolic analysis revealed a series of genes involved in cutin and suberin biosynthesis, transport and polymerization differentially expressed between the two groups. Furthermore, the expression levels of genes involved in the stress response and in hormone biosynthesis and signaling were significantly altered in fruits with contrasting phenotypes. Finally, a number of transcription factors, including those of the MYB, NAC, bHLH and bZIP families, were differentially expressed. Taken together, the results suggest that the multilayered mechanism through which bagging alleviates pear fruit semi-russeting is complex, and the large number of candidate genes identified provides a good foundation for future functional studies.

4.
Phys Chem Chem Phys ; 22(48): 28222-28229, 2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33295337

RESUMO

Obtaining tunable magnetic states in geometrically frustrated multiferroic compound CoCr2O4 by tuning the sublattice magnetic coupling is indeed of high interest from the fundamental and applied points of view. In this work, Fe substitution effects in Co(Cr1-xFex)2O4 (0 ≤ x ≤0.5) are experimentally investigated through detailed measurements of the crystalline structure and magnetization. Our experiments reveal that the samples undergo a magnetic transition characterized by a sharp variation in magnetization from 94 K at x = 0 to 317 K at x = 0.5. The field-cooled process shows that a magnetization reversal phenomenon is observed under a stable positive magnetic field when the measurement undergoes the compensation temperature. A magnetic field-assisted switching effect is realized near the compensation temperature, which possesses the characteristics of high repeatability and stability. The molecular field coefficients are evaluated based on the ferrimagnetic Curie-Weiss fitting, and the exchange interactions within and between the sublattices show a relationship of |JAA| < |JAB| < |JBB|. The magnetization reversal in Co(Cr1-xFex)2O4 is considered to be attributed to the coexistence and competition of A-A, A-B and B-B magnetic interactions, as well as the weakening of spin frustration.

5.
Infect Drug Resist ; 13: 4147-4154, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33244244

RESUMO

Purpose: To predict the risk of hospital deaths in patients with hospital-acquired pneumonia (HAP) caused by multidrug-resistant Acinetobacter baumannii (MDR-AB) infection. Patients and Methods: A total of 366 patients who were diagnosed with HAP caused by MDR-AB infection were enrolled between January 2013 and December 2016. The sociological characteristics and clinical data of these cases were collected. Univariate and multivariate logistic analyses were used to explore the risk factors of hospital deaths before medication and after drug withdrawal. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) were utilized to assess the predictive effectiveness of the models with or without the adjustment. Results: Hospital deaths occurred in 142 cases (38.80%). The results showed that acute physiology and chronic health evaluation II (APACHE II) and sequential organ failure assessment (SOFA) scores before medication and after drug withdrawal were associated with the risk of hospital deaths. Adjusting the covariants including the age, autoimmune disease, venous cannula, transfer of patients from other hospitals, and APACHE II score at admission, then no differences were discovered in predicting the hospital deaths between adjusted APACHE II and adjusted SOFA scores before medication (AUC: 0.808 vs 0.803, P =0.614) and after drug withdrawal (AUC: 0.876 vs 0.878, P =0.789). Conclusion: Before medication or after drug withdrawal, the adjusted APACHE II and adjusted SOFA scores all performed well in determining the predictive effectiveness of the hospital deaths in patients with HAP caused by MDR-AB infection, indicating that the appropriate infection control may reduce the occurrence of nosocomial deaths and improve the prognosis.

6.
J Clin Virol ; 133: 104685, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33220548

RESUMO

BACKGROUND: With the introduction of molecular diagnostic techniques over the past decades, different kinds of viral pathogens in the same sample are detected simultaneously more frequently. Nevertheless, influenza virus (Flu) and respiratory syncytial virus (RSV) coinfection in adults was reported only occasionally. Moreover, the clinical implications of Flu/RSV coinfection in the respiratory tract of adults remain unclear. METHODS: This retrospective study analyzed adult patients with acute respiratory infection from January 2017 to June 2019 in China-Japan Friendship Hospital. RESULTS: A total of 574, 235 and 113 patients were positive for influenza A-only (FA-only), influenza B-only (FB-only) and RSV-only in influenza seasons (from Nov 2017 to Mar 2018 and from Nov 2018 to Mar 2019), respectively. Of these, 19 cases were coinfected by Flu and RSV and admitted to this hospital. Compared with 809 Flu-only infected patients and 113 RSV-only infected patients, both the rates of intensive care unit(ICU) admission and use of invasive mechanical ventilation in Flu/RSV coinfected patients were higher (ICU admission: 47.4% vs. 20.1%, P=0.004; 47.4% vs. 22.1%, P=0.020; invasive mechanical ventilation: 47.4% vs.13.2%, P<0.001; 47.4% vs. 17.7%, P=0.004). Furthermore, 60-day all-cause mortality attributed to Flu/RSV coinfections was significantly greater than that for Flu and RSV mono-infected patients (36.8% vs. 8.0%,P<0.001; 36.8% vs. 11.5%, P=0.004. CONCLUSION: The findings of this study suggest that coinfection of Flu/RSV in adults is associated with a high adverse outcome. Thus, Flu/RSV coinfections should be increasingly appreciated and given appropriate management.

7.
Infect Drug Resist ; 13: 4115-4123, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33209041

RESUMO

Purpose: Pseudomonas aeruginosa bacteremia presents a severe challenge to hospitalized patients. However, to date, the risk factors for mortality among inpatients with P. aeruginosa bacteremia in China remain unclear. Patients and Methods: This retrospective multicenter study was performed to analyze 215 patients with culture-confirmed P. aeruginosa bacteremia in five healthcare centers in China during the years 2012-2019. Results: Of 215 patients with P. aeruginosa bacteremia, 61 (28.4%) died during the study period. Logistic multivariable analysis revealed that cardiovascular disease (OR=3.978, P=0.001), blood transfusion (OR=5.855, P<0.001) and carbapenem-resistant P. aeruginosa (CRPA) phenotype (OR=4.485, P=0.038) constituted the independent risk factors of mortality. Furthermore, both CRPA and multidrug-resistant P. aeruginosa (MDRPA) phenotypes were found to be significantly associated with 5-day mortality (Log-rank, P<0.05). Conclusion: This study revealed a high mortality rate amongst hospitalized patients with P. aeruginosa bacteremia, and those with cardiovascular diseases, CRPA and MDRPA phenotypes, should be highlighted and given appropriate management in China.

8.
ACS Med Chem Lett ; 11(11): 2195-2203, 2020 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-33214829

RESUMO

Bruton's tyrosine kinase (BTK) has been shown to play a key role in the pathogenesis of autoimmunity. Therefore, the inhibition of the kinase activity of BTK with a small molecule inhibitor could offer a breakthrough in the clinical treatment of many autoimmune diseases. This Letter describes the discovery of BMS-986143 through systematic structure-activity relationship (SAR) development. This compound benefits from defined chirality derived from two rotationally stable atropisomeric axes, providing a potent and selective single atropisomer with desirable efficacy and tolerability profiles.

9.
Phys Chem Chem Phys ; 22(42): 24633-24639, 2020 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-33095223

RESUMO

In nano-confined systems, the properties of a fluid are different from those of macroscopic systems, and the properties of a nanotube can significantly affect water transport. However, our knowledge of the effects of nanotube shape is far from adequate. In the present work, we study the properties of a fluid transporting in different nano-confined configurations by molecular dynamics simulations. This study is aimed at gaining insight into the transport of water molecules in carbon nanotubes with different configurations. We find that the closer of channel shape to the circular nanotube (more sides of the channel), the lower friction coefficient of the solid-liquid interface has and the friction coefficient of nanochannels increases with R when R < 1.0 nm. The friction coefficient converges to a stable value (close to the friction coefficient of graphene/water) when R > 1.0 nm. A variety of configurations leads to the variation of the fluid properties in nanotubes. Our results can be applied to the nanofluid properties of a complex channel structure and water nanochannel microscopic design.

10.
Stem Cell Res Ther ; 11(1): 330, 2020 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-33100224

RESUMO

BACKGROUND: We have previously verified the beneficial effects of exosomes from endothelial progenitor cells (EPC-EXs) in ischemic stroke. However, the effects of EPC-EXs in hemorrhagic stroke have not been investigated. Additionally, miR-137 is reported to regulate ferroptosis and to be involved in the neuroprotection against ischemic stroke. Hence, the present work explored the effects of miR-137-overexpressing EPC-EXs on apoptosis, mitochondrial dysfunction, and ferroptosis in oxyhemoglobin (oxyHb)-injured SH-SY5Y cells. METHODS: The lentiviral miR-137 was transfected into EPCs and then the EPC-EXs were collected. RT-PCR was used to detect the miR-137 level in EPCs, EXs, and neurons. The uptake mechanisms of EPC-EXs in SH-SY5Y cells were explored by the co-incubation of Dynasore, Pitstop 2, Ly294002, and Genistein. After the transfection of different types of EPC-EXs, flow cytometry and expression of cytochrome c and cleaved caspase-3 were used to detect the apoptosis of oxyHb-injured neurons. Neuronal mitochondrial function was assessed by reactive oxygen species (ROS) level, mitochondrial membrane potential (MMP) depolarization, and cellular ATP content. Cell ferroptosis was measured by lipid peroxidation, iron overload, degradation of glutathione, and glutathione peroxidase 4. Additionally, recombinational PGE2 was used to detect if activation of COX2/PGE2 pathway could reverse the protection of miR-137 overexpression. RESULTS: The present work showed (1) EPC-EXs could be taken in by SH-SY5Y cells via caveolin-/clathrin-mediated pathways and macropinocytosis; (2) miR-137 was decreased in neurons after oxyHb treatment, and EXsmiR-137 could restore the miR-137 levels; (3) EXsmiR-137 worked better than EXs in reducing the number of apoptotic neurons and pro-apoptotic protein expression after oxyHb treatment; (4) EXsmiR-137 are more effective in improving the cellular MMP, ROS, and ATP level; (5) EXsmiR-137, but not EXs, protected oxyHb-treated SH-SY5Y cells against lipid peroxidation, iron overload, degradation of glutathione, and glutathione peroxidase 4; and (6) EXsmiR-137 suppressed the expression of the COX2/PGE2 pathway, and activation of the pathway could partially reverse the neuroprotective effects of EXsmiR-137. CONCLUSION: miR-137 overexpression boosts the neuroprotective effects of EPC-EXs against apoptosis and mitochondrial dysfunction in oxyHb-treated SH-SY5Y cells. Furthermore, EXsmiR-137 rather than EXs can restore the decrease in miR-137 levels and inhibit ferroptosis, and the protection mechanism might involve the miR-137-COX2/PGE2 signaling pathway.

11.
Biosens Bioelectron ; 170: 112598, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33035901

RESUMO

-Label-free electrochemical aptasensors for cancer biomarker detection can be a promising means for early detection of cancer due to their high sensitivity, selectivity, and stability, and low cost. In this study, a highly sensitive and selective label-free electrochemical aptasensor based on carbon microelectromechanical systems (C-MEMS) was developed for the detection of platelet-derived growth factor-BB (PDGF-BB). The active electrodes of the aptasensors were synthesized via carbonization of SU-8 derived electrodes at high temperatures in an oxygen-free furnace. An oxygen-plasma oxidation treatment was used to functionalize the C-MEMS electrodes, which provided efficient covalent immobilization of amino terminated affinity aptamers. The turn-off and turn-on detection strategies-based on capacitance and resistance measurement, respectively-were employed. The capacitance detection strategies exhibited a wide linear response range of 0.01-50 nM, with a high sensitivity of 3.33 mF cm-2 Logc-1 (unit of c, nM) and a low limit of detection of 7 pM (S/N = 3). The resistance detection strategies exhibited an even wider linear response range of 0.005-50 nM, and a lower limit of detection of 1.9 pM (S/N = 3), with a high sensitivity of 1.65 × 103 Ω Logc-1 (unit of c, nM). Both detection strategies provided high selectivity for PDGF-BB and high stability of 90.34% after 10 days. This research demonstrates that the developed label-free electrochemical C-MEMS based PDGF-BB aptasensor is highly sensitive, selective, and robust. This aptasensor is a promising prospect for the highly demanding task of early detection of cancer biomarkers.

12.
J AOAC Int ; 2020 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-33078194

RESUMO

BACKGROUND: Chromium is an interesting element because its toxicity depends on its speciation. Thus, knowledge of Cr speciation in cow milk is essential to human health. OBJECTIVE: This study aims to achieve real bioaccessible species in cow milk, including Cr(III), Cr(VI), residual, digestible, and total Cr. METHODS: Samples were treated with artificial gastric juice, followed by dispersive micro-solid phase extraction (DMSPE) combined with ICP-MS for Cr speciation. Fibrous g-C3N4@TiO2 nanocomposites (FGCTNCs) were used as a novel adsorbent for DMSPE. RESULTS: The method detection limits were 110 pg/g (Cr(III)) and 260 pg/g (Cr(VI)) for milk powder (0.1 g), and 5.1 pg/g (Cr(III)) and 13 pg/g (Cr(VI)) for liquid cow milk (2 mL). The relative standard deviations (RSDs), obtained by analyzing the standard solutions containing 1.0 ng/mL of the analytes in sequence for nine times, were 4.3% and 5.1% for Cr(III) and Cr(VI), respectively. Linearity was observed over the range of 4 magnitude orders with correlation coefficients better than 0.9961. The enrichment factor of 100 was obtained. The majority of Cr in the samples was transferred into digestion solution. The content of Cr(III) is much higher than that of Cr(VI) in the digestion solution. CONCLUSIONS: This method has the advantages of reduced solvent consumption, less adsorbent dosage, and high extraction efficiency. It may become a valuable strategy for elemental species in food samples. HIGHLIGHTS: The samples were treated with artificial gastric juice to avoid the inter-conversion of species. FGCTNCs exhibit the merits of N-rich functional groups and selective adsorption for the analytes.

13.
Nanoscale ; 12(34): 17870-17879, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32840546

RESUMO

Thermal transfer across solid-liquid interfaces is influenced by multiple factors such as surface wettability, interfacial water layer density, molecular structure, and mass density depletion length. However, the dominant factors in interfacial heat transport are yet to be investigated. In this work, we explore the contributions from these factors by employing the Pd-water model for water molecules forming ordered, partially ordered, and disordered structures on Pd (100), (110) and (111) surfaces, respectively. The results revealed that the ordered water layer on the (100) surface can introduce a "phonon bridge" at the solid-liquid interface to improve thermal transfer, while the partially ordered water layer on the (110) surface can further promote thermal transfer due to the enhanced interfacial friction. On the other hand, the decreased density depletion length also makes dominant contributions to the enhancement of interfacial thermal transfer. The results are explained by the interfacial friction coefficient, surface potential energy distribution and density depletion length. We also introduce an efficient technique by tuning the vacancy defects on the solid surface to tune the atomic structure as well as the thermal transfer. Our study reveals the complex relationship between the atomic structure of the crystal face, the water layer structure and the thermal boundary conductance, which will inspire more experimental and theoretical studies toward the improvement of interfacial thermal transport by tuning the structure of the water layer.

14.
Interv Neuroradiol ; 26(5): 602-607, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32777960

RESUMO

BACKGROUND: Intracranial artery atherosclerotic stenosis (ICAS) is among the causes of intracranial large artery occlusion (LVO). The optimal treatment strategy for patients with ischemic stroke due to ICAS-related LVO remains unclear. In this retrospective case series, we discussed our experience with direct angioplasty as frontline therapy for ICAS-related LVO. METHODS: We extracted data for patients who had a known pre-existing ICAS and undergone direct angioplasty as frontline therapy for ICAS-related LVO in the anterior circulation at our institution between January 2019 and December 2019. We analysed procedural details, the degree of reperfusion, functional outcomes, and complications. Successful reperfusion was defined as a modified Treatment in Cerebral Ischemia (mTICI) score of 2 b - 3. Functional outcomes at 90 days were assessed using modified Rankin Scale (mRS) scores (good outcome: mRS of 0-2). RESULTS: We analysed data for five patients (mean age: 51.6 ± 11 years). The mean time from symptom onset to recanalization was 371 ± 38.6 min. Occlusions involved the first segment of the middle cerebral artery in four patients and the intracranial internal carotid artery in one patient. Successful reperfusion was achieved in four (80%) patients. The remaining patient (20%) underwent intracranial stenting as rescue therapy, achieving a final mTICI of 2a. No re-occlusion was observed on follow-up images. Four patients (80%) achieved good outcomes at 90 days. There were no cases of symptomatic intracranial hemorrhage, although asymptomatic intracranial haemorrhage was observed in one patient. CONCLUSION: Direct angioplasty may represent an alternative treatment strategy in patients with acute ischemic stroke due to known ICAS-related LVO.

15.
J Phys Chem Lett ; 11(17): 7002-7008, 2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32786218

RESUMO

Unwinding the double helix of the DNA molecule is the basis of gene duplication and gene editing, and the acceleration of this unwinding process is crucial to the rapid detection of genetic information. Based on the unwinding of six-base-pair DNA duplexes, we demonstrate that a terahertz stimulus at a characteristic frequency (44.0 THz) can serve as an efficient, nonthermal, and long-range method to accelerate the unwinding process of DNA duplexes. The average speed of the unwinding process increased by 20 times at least, and its temperature was significantly reduced. The mechanism was revealed to be the resonance between the terahertz stimulus and the vibration of purine connected by the weak hydrogen bond and the consequent break in hydrogen bond connections between these base pairs. Our findings potentially provide a promising application of terahertz technology for the rapid detection of nucleic acids, biomedicine, and therapy.

16.
Nanotechnology ; 31(45): 455205, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-32736367

RESUMO

Large-size luminescent solar concentrators (LSCs), which act as a complement to silicon-based photovoltaic (Si-PV) systems, still suffer from low power conversion efficiency (PCE). How to improve the performance of LSCs, especially large ones, is currently a hot research topic. Traditional LSCs have only a single transmission mode of fluorescence from the luminescent materials to the Si-PV, but here we introduce a new idea to improve the absorption of Si-PV by employing dual transmission modes of both fluorescence and scattering light. To prepare LSCs with dual mode transmission, Si-PV systems are coupled around the edges of a light-harvesting slice, which is prepared by ultraviolet light-induced polymerization of methyl methacrylate (MMA) solution containing both luminescent CsPbBr3 and TiO2 nanocrystals (NCs). When the sun light or incident light is coupled into the light-harvesting slice, CsPbBr3 NCs can convert the incident light into fluorescence, and then partly transmit to Si-PV at the edges, where the light is finally converted into electrical energy. Besides the traditional fluorescence transmission mode, the addition of TiO2 brings another transmission mode, namely the scattering of incident light to Si-PV, leading to an increase in PCE. In comparison to that of pure CsPbBr3-based LSCs without the addition of TiO2 (0.97%), the PCE of TiO2-doped LSCs with a large size of 20 cm × 20 cm is improved to 1.82%. The maximal PCE appears for LSCs with a size of 5 cm × 5 cm, reaching 2.62%. The reported method of dual transmission modes is a new alternative way to improve the performance of LSC devices, which does not need to change the optical properties of luminescent materials. Moreover, the production process is simple, low-cost and suitable for preparing large area LSCs, further promoting the application of LSCs.

17.
PLoS One ; 15(7): e0236740, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32722706

RESUMO

Tryptic digestion of proteins followed by liquid chromatography with tandem mass spectrometry analysis is an extensively used approach in proteomics research and biopharmaceutical product characterization, owing to the high level of cleavage fidelity produced with this technique. However, nonspecific trypsin cleavages have been frequently reported and shown to be related to a number of digestion conditions and predigestion sample treatments. In this work, we reveal that, for a number of commercial trypsins, reconstitution and storage conditions can have a significant impact on the occurrence of trypsin nonspecific cleavages. We analyzed the tryptic digestion of a variety of biotherapeutics, using trypsins reconstituted under different conditions. The results indicate that, for many commercial trypsins, commonly recommended reconstitution/storage conditions (mildly acidic, e.g., 50 mM acetic acid, 1 mM HCl) can actually promote nonspecific trypsin activities, which are time dependent and can be as high as 20% in total relative abundance. In contrast, using water for reconstitution and storage can effectively limit nonspecific cleavages to 1%. Interestingly, the performances of different commercial trypsins were found to be quite distinct in their levels of nonspecific cleavages and responses to the two reconstitution conditions. Our findings demonstrate the importance of choosing the appropriate trypsin for tryptic digestion and the necessity of assessing the impact of trypsin reconstitution and storage on nonspecific cleavages. We advocate for manufacturers of commercial trypsins to reevaluate manufacturing processes and reconstitution/storage conditions to provide good cleavage specificity.


Assuntos
Ácidos/química , Fragmentos de Peptídeos/metabolismo , Proteínas/metabolismo , Proteólise , Proteômica/métodos , Tripsina/metabolismo , Humanos , Fragmentos de Peptídeos/análise , Fragmentos de Peptídeos/isolamento & purificação
19.
Infect Drug Resist ; 13: 1713-1721, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606821

RESUMO

Background: Multidrug-resistant (MDR) ST11 hypervirulent Klebsiella pneumoniae (hvKp) is emerging in China. Purpose: The aim of this study was to track the transmission and evolution of hvKp. Materials and Methods: A retrospective study focused on Kp infection was conducted. Clinical data were collected from electronic medical records. Whole-genome sequencing of Kp strains was performed. Single-nucleotide polymorphisms (SNPs) were analyzed and a transmission map was constructed. Sequence type, and antimicrobial and virulence-associated genes were characterized. Strains with some combination of the virulence genes, prmpA, prmpA2, iucA, iroB, and peg-344, were defined as hvKp. Kp virulence phenotypes were evaluated using the Galleria mellonella model. Results: All 33 Kp strains were MDR-Kp and 13 (39.4%) were hvKp. Most hvKp strains (84.6%, 11/13) were hospital-acquired infections (HAIs). Two unique combinations of virulence-associated genes were detected among hvKp strains. Eleven cases were associated with prmpA2+iucA and two strains presented with peg-344+ prmpA+ prmpA2+iucA. Surprisingly, two community-acquired MDR-hvKp infection cases were identified. Eight hvKp strains (61.5%, 8/13) exhibited a hypervirulent phenotype in the G. mellonella model. Five MDR-hvKp strains with the hypervirulence phenotype originated from a single cluster. Additionally, nine clones were identified among the two clades, six of which were hvKp. Moreover, the hvKp in clade 1 carried the IncHI1B plasmid replicon, whereas none of the hvKp strains in clade 2 harbored IncHI1B. These data, showing that different hvKp clones distributed into separate clades, indicate that transmission and evolution occurred within the hospital. Conclusion: During inter-host evolution and transmission, various virulence clusters of the epidemic clone, MDR-ST11, converged, conferring phenotypic virulence heterogeneity and spread within the hospital and possibly the community. Mobile/conjugative genetic elements associated with virulence-encoding gene clusters might emerge and have been transmitted within the hospital, suggesting that enhanced ongoing surveillance is essential.

20.
Planta ; 252(1): 9, 2020 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-32602044

RESUMO

MAIN CONCLUSION: NO was involved in H2-induced adventitious rooting by regulating the protein and gene expressions of PM H+-ATPase and 14-3-3. Simultaneously, the interaction of PM H+-ATPase and 14-3-3 protein was also involved in this process. Hydrogen gas (H2) and nitric oxide (NO) have been shown to be involved in plant growth and development. The results in this study revealed that NO was involved in H2-induced adventitious root formation. Western blot (WB) analysis showed that the protein abundances of plasma membrane H+-ATPase (PM H+-ATPase) and 14-3-3 protein were increased after H2, NO, H2 plus NO treatments, whereas their protein abundances were down regulated when NO scavenger carboxy-2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTI O) was added. Moreover, the mRNA abundances of the HA3 and 14-3-3(7) gene as well as the activities of PM H+-ATPase (EC 3.6.1.35) and H+ pump were in full agreement with the changes of protein abundance. Phosphorylation of PM H+-ATPase and the interaction of PM H+-ATPase and 14-3-3 protein were detected by co-immunoprecipitation analysis. H2 and NO significantly up regulated the phosphorylation of PM H+-ATPase and the interaction of PM H+-ATPase and 14-3-3 protein. Conversely, the stimulation of PM H+-ATPase phosphorylation and protein interaction were significantly diminished by cPTIO. Protein interaction activator fusicoccin (FC) and inhibitor adenosine monophosphate (AMP) of PM H+-ATPase and 14-3-3 were used in this study, and the results showed that FC significantly increased the abundances of PM H+-ATPase and 14-3-3, while AMP showed opposite trends. We further proved the critical roles of PM H+-ATPase and 14-3-3 protein interaction in NO-H2-induced adventitious root formation. Taken together, our results suggested that NO might be involved in H2-induced adventitious rooting by regulating the expression and the interaction of PM H+-ATPase and 14-3-3 protein.

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