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Fatty acid biosynthesis is essential for bacterial survival. In recent years, components of this biosynthetic pathway have aroused wide concern. -Ketoacyl-acyl carrier protein synthase III (FabH) is a particularly attractive target which catalyzes the initial step of fatty acid biosynthesis. In this review, fatty acid biosynthesis, recent advances in the research of FabH as well as related inhibitors are reviewed. Finally, we also discuss the prospect and developmental trend of FabH inhibitors as anti-bacterial agents.

We have investigated reactions in condensed CF 2Cl 2induced by electrons of subexcitation energies under ultrahigh vacuum conditions. The yields of the CF 2Cl 2radiolysis products (C 2F 4Cl 2, C 2F 3Cl 3, and C 2F 2Cl 4) were determined as functions of electron energy ( Ei) (∼1 to ∼4.5 eV) and electron dose (fluence) (1.5 × 10 16e/cm 2to 2.2 × 10 16e/cm 2) by postirradiation temperature-programmed desorption. In general, we ascribe the formation of these radiolysis products to reactions of •CFCl 2and •CF 2Cl radicals, which are generated by dissociative electron attachment (DEA) to CF 2Cl 2. Consistent with condensed-phase experiments, which report the electron stimulated desorption of F −ions via transient negative ion formation at incident electron energies near 4 eV, the yield of products C 2F 2Cl 4and C 2F 3Cl 3derived from reactions of •CFCl 2show maxima near ∼3 eV. The production of C 2F 3Cl 3and C 2F 4Cl 2at electron energies as low as 2 eV indicates that •CF 2Cl is generated; however, the absence of a clear resonance maximum in the C 2F 4Cl 2yield function indicates that the production of •CF 2Cl radicals via DEA is not the sole or dominant pathway for the formation of C 2F 4Cl 2. Indeed, the variation of radiolysis product yield with electron dose suggests that the C 2F 4Cl 2signal may additionally be generated by reactions of CF 2Cl 2with the difluorocarbene radical ( :CF 2), which we propose is also formed by DEA to CF 2Cl 2. Although numerous studies have revealed chemical damage induced by DEA, our results represent one of the first studies to unambiguously demonstrate (via a clear signature of resonance) chemical synthesis induced by this process.

The low-energy electron-induced chemistry of condensed CCl4has been investigated with use of post-irradiation temperature-programmed desorption. These experiments were partly motivated by the growing interest in developing facile and economical methods for decomposing CCl4and other halocarbons which through widespread use in industry have become potent environmental pollutants. The experimental procedure involves low-energy (50 eV) electron irradiation (fluence ≤2 × 1016electrons cm-2) of nanoscale thin films (5 monolayers) of CCl4grown at 100 K on a Mo(110) single crystal under ultrahigh vacuum (UHV) conditions. Results of post-irradiation temperature-programmed desorption experiments were used to identify C2Cl4, C2Cl6, C3Cl6, C4Cl6, and C5Clxas low-energy electron-induced reaction products of condensed CCl4. Two longer chain chlorocarbon oligomers with six or more carbons were also detected but not identified. Although low-energy electron-induced oligomerization reactions have been previously reported for molecules such as thiophene and cyclopropane, the results presented herein represent the first study to specifically identify the products of such reactions, demonstrating the utility of post-irradiation temperature-programmed desorption experiments to study the radiation chemistry of condensed matter.

Two new benzojfluoranthene-based secondary metabolites named daldinone C (1) and daldinone D (2), along with two known metabolites, altechromone A and (4S)-5,8-dihydroxy-4-methoxy--tetralone, were isolated from the CHCl3/MeOH (1:1) extract of a solid culture of the endophyte Hypoxylon truncatumIFB-18 harbored inside the symptomless stem tissue of Artemisia annua. The structures of the new compounds were elucidated by MS and 1D and 2D NMR spectra and by X-ray diffraction analysis. Their absolute configurations were determined unambiguously by a combination of their CD data and the established exciton chirality rule. Compounds 1and 2were substantially cytotoxic against SW1116 cells, with IC50values of 49.5 and 41.0 M, respectively, comparable to that (37.0 M) of 5-fluorouracil. The biosynthetic pathway for 1and 2was postulated with the natural occurrence of benzojfluoranthene analogues discussed in brief.

Chaetominine (1), an alkaloidal metabolite with a new framework, was characterized from the solid-substrate culture of Chaetomiumsp. IFB-E015, an endophytic fungus on the apparently healthy Adenophora axillifloraleaves. Its structure was determined by a combination of its spectral data and single-crystal X-ray diffraction analysis, with its absolute configuration elucidated by Marfey's method. Chaetominine was more cytotoxic than 5-fluorouracil against the human leukemia K562 and colon cancer SW1116 cell lines.

Caveolin-1 is a principal component of caveolae membranes in vivo. Caveolin-1 mRNA and protein expression are lost or reduced during cell transformation by activated oncogenes. Interestingly, the human caveolin-1 gene is localized to a suspected tumor suppressor locus (7q31.1). However, it remains unknown whether caveolin-1 plays any role in regulating cell cycle progression. Here, we directly demonstrate that caveolin-1 expression arrests cells in the G(0)/G(1) phase of the cell cycle. We show that serum starvation induces up-regulation of endogenous caveolin-1 and arrests cells in the G(0)/G(1) phase of the cell cycle. Moreover, targeted down-regulation of caveolin-1 induces cells to exit the G(0)/G(1) phase. Next, we constructed a green fluorescent protein-tagged caveolin-1 (Cav-1-GFP) to examine the effect of caveolin-1 expression on cell cycle regulation. We directly demonstrate that recombinant expression of Cav-1-GFP induces arrest in the G(0)/G(1) phase of the cell cycle. To examine whether caveolin-1 expression is important for modulating cell cycle progression in vivo, we expressed wild-type caveolin-1 as a transgene in mice. Analysis of primary cultures of mouse embryonic fibroblasts from caveolin-1 transgenic mice reveals that caveolin-1 induces 1) cells to exit the S phase of the cell cycle with a concomitant increase in the G(0)/G(1) population, 2) a reduction in cellular proliferation, and 3) a reduction in the DNA replication rate. Finally, we demonstrate that caveolin-1-mediated cell cycle arrest occurs through a p53/p21-dependent pathway. Taken together, our results provide the first evidence that caveolin-1 expression plays a critical role in the modulation of cell cycle progression in vivo.

In an effort to develop a quantitative ligand-binding model for the receptor tyrosine kinases, a pharmacophore search was first used to identify structural features that are common in two novel sets of 12 molecules of the 3-substituted indolin-2-ones and 19 compounds of the benzylidene malononitriles with low-to-high affinity for HER2, a kind of receptor tyrosine kinase. The common pharmacophore model based on these 31 compounds was used as a template to obtain the aligned molecular aggregate, which provided a good starting point for 3D-QSAR analysis of only the 19 benzylidene malononitriles. Two molecular field analysis (MFA) techniques, including CoMFA and CoMSIA, were used to derive the quantitative structure−activity relationships of the studied molecules. From the studied results, it was obvious that the 3D-QSAR models based on the pharmacophore alignment were superior to those based on the simple atom-by-atom fits. Considering the flexibility of the studied molecules and the difference between the active conformers and the energy-lowest conformers, the pharmacophore model can usually provide the common features for the flexible regions. Moreover, the best CoMSIA model based on the pharmacophore hypothesis gave good statistical measure from partial least-squares analysis (PLS) (q2 0.71), which was slightly better than the CoMFA one. Our study demonstrated that pharmacophore modeling and CoMSIA research could be effectively combined. Results obtained from both methods helped with understanding the specific activity of some compounds and designing new specific HER2 inhibitors.

Photoluminescence (PL) of ZnO thin films prepared on c-Al2O3 substrates by pulsed laser deposition (PLD) are investigated. For all samples, roomtemperature (RT) spectra show a strong band-edge ultraviolet (UV) emission with a pronounced low-energy band tail. The origin of this UV emission is analyzed by the temperature dependence of PL spectra. The result shows that the UV emission at RT contains different recombination processes. At low temperature donor-bound exciton (D0X) emission plays a major role in PL spectra, while the free exciton transition (FX) gradually dominates the spectrum with increasing temperatures. It notes that at low temperature an emission band (FA) appears in low energy side of D0X and FX and can survive up to RT. Further confirmation shows that the origin of the band FA can be attributed to the transitions of conduction band electrons to acceptors (e, A0), in which the acceptor binding energy is estimated to be approximately 121 meV. It is concluded that at room temperature UV emission originates from the corporate contributions of the free exciton and free electrons-to-acceptor transitions.

Compared with the macrosystem case, the phase transition occurring in fragmenting cluster systems depicts a much richer story. However, most experimental observations have been restricted to an extremely partial view of this picture due to the technical limitations of a large-range scan of the energy deposited in a selected cluster system. Here, taking charge-selected C603+ and C604+ as model systems, we experimentally explore the fragmentation phase transition (FPT) over a large energy range and directly observe some of the most important features of the FPT, the multistage transformation, and the charge effect. [ABSTRACT FROM AUTHOR]

The momentum distributions of the recoil ions were measured for the single ionization of atomic targets (Ne, Ar) and of molecular targets (CH4, N2, CO2) at incident electron energies ranging from 80 to 220 eV by using the reaction microscope. It was found that there are a remarkable number of recoil ions with large longitudinal momenta, and the relative contribution of these ions for Ne (e, 2e) reactions decreases faster than that for Ar (e, 2e) reactions with the incident electron energy increasing. This observed feature can be qualitatively interpreted by the different effective potential of the target core experienced by the electrons. The appearance of the large longitudinal momentum recoil ions for CH4N2, and CO2 (e, 2e) reactions indicates that the strong interaction between the electron and the component-atoms target core in the molecules plays a significant role in the single ionization of small molecular targets. Depending on the independent atom model, we can intuitively understand the characteristics of the momentum distributions of the recoil ions CH+4, N+2, and CO+2, respectively. [ABSTRACT FROM AUTHOR]

Competing Interests: The authors declare no competing interests.

Competing Interests: The authors declare no competing interests.

Media is the principal source of public information, and people's trust in news has been a critical mechanism in social cohesion. In recent years, the vast growth of new media (e.g., internet news portals) has brought huge change to the way information is conveyed, cannibalizing much of the space of traditional media (e.g., traditional newspapers). This has led to renewed attention on media credibility. The study aims to explore the impact of media channel on trust in news and examine the role of news type. Twenty-six participants were asked to make trust-distrust decisions after reading a variety of news headlines from different media channels while undergoing electroencephalography (EEG) monitoring. The electrophysiological results showed that, for hard news (e.g., important news related to public life), the new media condition elicited smaller N100 and larger P200 amplitudes than the traditional media condition. However, for soft news (e.g., entertainment, and non-related to vital interest), there was no significant difference. The study suggests that the fitness of media channel and news type may influence the evaluation of news, impacting participants' affective arousal and attention allocation in the early stage and influencing trust in news. These results provide neurocognitive evidence of individuals' trust toward hard and soft news consumed via different media channels, yielding new insights into trust in media and contributing to media trust theory., Competing Interests: SL was employed by the company SDIC Mining Investment Co., Ltd., Beijing, China. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Fan, Liu, Pei, Wu and Zhu.)

Objective: The objective of this study is to investigate the allergen sensitization pattern among 4,203 children in the Shanxi region of China and to provide guidance for diagnosis and prevention of allergic diseases., Methods: A retrospective analysis was conducted on the allergen-specific immunoglobulin E (sIgE) results of 4,203 children aged 0-12 years from January to December in 2019. SIgE antibodies to 19 allergens in the serum sample were detected by enzyme ALLERGO-SORBENT testing., Results: In total, 49.70% (2,089/4,203) of children with allergic diseases were positive for sIgE, and the top 5 allergens were egg white 18.63% (783/4,203), artemisia 14.47% (608/4,203), milk 13.04% (548/4,203), ragweed 8.66% (364/4,203), and poplar/willow/elm 8.52% (358/4,203). Significant differences in the positive rate of food allergens and aeroallergens in different ages were found (p < 0.05). 50.98% (1,065/2,089) patients were sensitive to 2 or more allergens. The high sensitization rate in the >3-year group was significantly higher than the ≤3-year group (p < 0.05)., Conclusion: Egg white and artemisia are the most common allergens in children in northern China. This study provides allergic sensitization pattern of children and clinical epidemiological data in the region., (© 2020 S. Karger AG, Basel.)