Significance In nematodes, acyl-CoA oxidases function not only in primary metabolism, where they participate in the breakdown of long-chain fatty acids, but also in secondary metabolism, where they participate in the biosynthesis of the ascarosides, a family of pheromones that regulate development and behavior. Here, we provide a molecular basis for the diverse substrate specificities of the acyl-CoA oxidases. Unlike their homologs in other organisms, the acyl-CoA oxidases of nematodes bind ATP at the dimer interface, leading to a conformational change that promotes FAD cofactor binding and enzyme activity. Our results suggest a mechanism by which the biosynthesis of most ascarosides is increased under conditions that promote higher cellular ATP concentrations in the worm.
The development of efficient, low-cost, easy-to-use ambient ionization methods has been a major goal of modern mass spectrometry. In this Letter, we present a gas-free, voltage-free, economic, and safe desorption ionization method using the plasma generated by a radioactive element, americium-241, scavenged from smoke detectors that equip almost every household. No other energy sources, such as laser, discharge, fast-moving carrier gas, solvent droplet, ultrasound, or heat are needed. We name this new method as americium-241 desorption ionization (AmDI). AmDI is tested for the detection of more than 20 volatile and nonvolatile chemicals under different sampling conditions, and the detection limit can be in the range of tens of picograms for some analytes. Mechanistically, we provide evidence that the α particles emitted from radioactive decay ionize ambient air, and the resulting plasma further energizes and ionizes the surface analytes for mass spectrometry detection. We anticipate wide applications of AmDI in mass spectrometric sampling in the near future because of the plethora of merits.
Background: This study aimed to explore the mechanisms underlying T‐cell differentiation in asthma. Methods and Results: Flow cytometry was performed to detect Th cells. LC‐MS/MS was performed to assess lipid metabolism. HE staining was performed to assess the pathological changes of the lung tissues. ELISA was performed to detect cytokine levels. The results of quantitative real‐time polymerase chain reaction (qRT‐PCR) and western blot showed that miR‐192‐5p expression was decreased, while SCD1 expression was increased in CD4 + T cells isolated from the peripheral blood of children with asthma. The dual luciferase reporter assay determined the direct interaction between miR‐192‐5p and SCD1. MiR‐192‐5p inhibitor reduced ASCL3 and PPARα, increased FASN and SREBP1c mRNA expression and protein levels in mouse spleen CD4 + T cells, and elevated Th2 and Th17 cells, but these effects were reversed by the SCD1 inhibitor. Oleic acid (OA) reduced Th1 cells and increased Th2 and Th17 cells in mouse spleen CD4 + T cells treated with an SCD1 inhibitor. Additionally, pri‐miR‐192‐5p expression was increased in CD4 + T cells isolated from the peripheral blood of asthmatic children, and the deletion of METTL3 upregulated pri‐miR‐192‐5p expression in an m6A‐dependent manner. MiR‐192‐5p mimic and inhibitor both reversed miR‐192‐5p and SCD1 expression affected by overexpression or deletion of METTL3, both in vivo and in vitro . Furthermore, METTL3 overexpression attenuated lung inflammation, elevated Th1 cells, and reduced Th2 and Th17 cells in CD4 + T cells isolated from the peripheral blood of asthmatic mice. These effects were reversed by the miR‐192‐5p inhibitor. Conclusion: These results suggest that METTL3/miR‐192‐5p/SCD1 axis regulates lipid metabolism and affects T cell differentiation, thus affecting asthma progression. This study may provide novel insights into the pathogenesis of asthma and a new treatment strategy.
Abstract The surface of atmospheric aqueous aerosol is covered with an organic film. However, there have been limited studies about the photochemical process between the organic coating and aqueous samples such as fogwater, which contains light absorbing brown carbon (BrC). Here, the interactional aging process between unsaturated fatty acids and aqueous samples was performed by laboratory studies and field observations. On the one hand, glycine and alanine were selected as organic nitrogen‐containing compounds to form BrC with carbonyl compounds like glyoxal or methylglyoxal. Oleic acid was induced to form organic peroxy radicals through H‐abstraction by the excited triplet BrC or hydroxyl radical (OH). On the other hand, one type of aqueous formation pathway of Criegee intermediates (CIs) was proposed through the oxidation of oleic acid. CIs may be formed by OH addition to C=C bonds and scavenged by interfacial reactions. Results from ultra‐high resolution Fourier transform ion cyclotron resonance mass spectrometry show that the synergistic effect of oleic acid and OH may have a higher oxidative capacity than OH. Furthermore, our study demonstrates that oleic acid can improve the aqueous oxidation ability by producing oxygen‐containing radicals. These findings highlight that the formation of free radicals is greatly influenced by photochemical reactions, which further reveal the complexities of fog organic chemistry.
Water is considered as an inert environment for the dispersion of many chemical systems. However, by simply spraying bulk water into microsized droplets, the water microdroplets have been shown to possess a large plethora of unique properties, including the ability to accelerate chemical reactions by several orders of magnitude compared to the same reactions in bulk water, and/or to trigger spontaneous reactions that cannot occur in bulk water. A high electric field (∼109 V/m) at the air–water interface of microdroplets has been postulated to be the probable cause of the unique chemistries. This high field can even oxidize electrons out of hydroxide ions or other closed-shell molecules dissolved in water, forming radicals and electrons. Subsequently, the electrons can trigger further reduction processes. In this Perspective, by showing a large number of such electron-mediated redox reactions, and by studying the kinetics of these reactions, we opine that the redox reactions on sprayed water microdroplets are essentially processes using electrons as the charge carriers. The potential impacts of the redox capability of microdroplets are also discussed in a larger context of synthetic chemistry and atmospheric chemistry.
The simple homodinuclear M-M single bonds for group II and XII elements are difficult to obtain as a result of the fulfilled s2 electronic configurations, consequently, a dicationic prototype is often utilized to design the M+ −M+ single bond. Existing studies generally use sterically bulky organic ligands L− to synthesize the compounds in the L− −M+ −M+ −L− manner. However, here we report the design of Mg-Mg and Zn-Zn single bonds in two ligandless clusters, Mg2B7− and Zn2B7−, using density functional theory methods. The global minima of both of the clusters are in the form of M22+(B73−), where the M-M single bonds are positioned above a quasi-planar hexagonal B7 moiety. Chemical bonding analyses further confirm the existence of Mg-Mg and Zn-Zn single bonds in these clusters, which are driven by the unusually stable B73− moiety that is both σ and π aromatic. Vertical detachment energies of Mg2B7− and Zn2B7− are calculated to be 2.79 eV and 2.94 eV, respectively, for the future comparisons with experimental data.
Abstract To investigate the impact of viral and bacterial co-infection in hospitalised children with Mycoplasma pneumoniae pneumonia (RMPP). Retrospective analysis of 396 children with RMPP in our hospital admitted between 1 January 2011 and 31 December 2016 was performed. Nasal aspirate samples were collected for pathogen detection and clinical data were collected. We analysed clinical characteristics, lung imaging characteristics and pathogenic species among these children. Of the 396 RMPP cases, 107 (27.02%) had co-infection with other pathogen, with Streptococcus pneumoniae , Haemophilus influenzae and Staphylococcus aureus being the most common bacteria of infection and human bocavirus (HBoV), human rhinovirus, respiratory syncytial virus being the most common viruses of infection. Children with co-infection were younger than that with single infection ( P = 0.010). Children with both virus and bacteria co-infection had been the youngest ( P = 0.040). Children with co-infection had a longer fever process, higher leukocyte count, higher C-reactive protein compared with single infection ( P < 0.05). Children with co-infection had a higher percentage of pnemothorax and diffuse large area of inflammation in chest X-ray manifestation compared with children with single infection ( P < 0.05). S. pneumonia and HBoV was the leading cause of co-infection in RMPP. Co-infections led to more disease severity in children with RMPP compared with single infections.
Objective
To analyze the clinical characteristics and laboratory indexes of pneumonia complicated with pertussis syndrome in Suzhou area in order to provide the basis for rational treatment.
Methods
Children who had been hospitalized at Department of Respiratory, Children′s Hospital of Soochow University during January 2012 to October 2016 were enrolled and diagnosed as pneumonia complicated with pertussis syndrome.A total of 236 cases were enrolled.Multiple pathogen detection and clinical information were collected in all patients.The subjects were divided into 28 days -<3 months group, 3-<6 months old group, 6-<12 months old group and≥12 months old group.The clinical data of children in each age group were retrospectively analyzed.
Results
Pneumonia complicated with pertu-ssis syndrome was easy to occur within 6 months of infants, with the highest incidence in the 3-<6 months group, there was a significant difference among the different age groups(χ2=231.870, P<0.05)[28 d-<3 months group: 5.3%(102/1 910 cases), 3-<6 months group: 5.7%(76/1 341 cases), 6-<12 months group: 2.0%(36/1 762 cases), ≥12 months group: 0.4%(22/5 304 cases)]. The patients could become sick all the year round, with the highest incidence in summer[2.6%(72/2 740 cases)in spring, 3.7%(96/2 611 cases)in summer, 2.1%(56/2 749 cases)in autumn, and 0.48%(12/2 487 cases)in winter], and there were significant differences among the different seasons (χ2=62.380, P<0.001). Clinical symptoms were paroxysmal spasmodic cough, 33.0% (78/236 cases) of the performance with wheezing, mainly in the older than 3 months group.The incidence of fever was positively correlated with age(χ2=12.938, P<0.05). Peripheral white blood cell count and lymphocyte percentage increased, and the 3-<6 months old group increased markedly.White blood cell count as high as (19.01±11.99)×109/L, the highest percentage of lymphocytes was up to 0.80, platelets were significantly increased in more than 80% of children.The incidence of C-reactive protein (CRP) was negatively correlated with age, 28 days-<3 months group more prone to have high CRP.Pulmonary inflammatory pathology showed multiple pulmonary involvement by chest radiography, and it was more likely to occur in 28 d-<3 months group.Viruses, bacteria and mycoplasma pneumoniae (MP) could cause pneumonia associated with pertussis syndrome, and mixed infection occurred in 56 cases.The top three pathogens were rhinovirus, MP and Streptococcus pneumoniae, and mixed infection was more prone to occur in 28 d-<3 months group.
Conclusion
Pneumonia complicated with pertussis syndrome is easy to occur within 6 months of infants, with the highest incidence in summer.Viruses, bacteria and MP all could cause pneumonia associated with pertussis syndrome, and mixed infection could occur in some cases.The top three pathogens are rhinovirus, MP and Streptococcus pneumoniae.
Key words:
Pertussis syndrome; Clinical feature; Child
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