Identification, Characteristics and Mechanism of 1-Deoxy-N-acetylglucosamine from Deep-Sea Virgibacillus dokdonensis MCCC 1A00493.

Xanthomonas oryzae pv. oryzae, which causes rice bacterial blight, is one of the most destructive pathogenic bacteria. Biological control against plant pathogens has recently received increasing interest. 1-Deoxy-N-acetylglucosamine (1-DGlcNAc) was extracted from the supernatant of Virgibacillus dokdonensis MCCC 1A00493 fermentation through antibacterial bioassay-guided isolation. Its structure was elucidated by LC/MS, NMR, chemical synthesis and time-dependent density functional theory (TD-DFT) calculations. 1-DGlcNAc specifically suppressed X. oryzae pv. oryzae PXO99A (MIC was 23.90 µg/mL), but not other common pathogens including Xanthomonas campestris pv. campestris str.8004 and Xanthomonas oryzae pv. oryzicola RS105. However, its diastereomer (2-acetamido-1,5-anhydro-2-deoxy-d-mannitol) also has no activity to X. oryzae pv. oryzae. This result suggested that activity of 1-DGlcNAc was related to the difference in the spatial conformation of the 2-acetamido moiety, which might be attributed to their different interactions with a receptor. Eighty-four unique proteins were found in X. oryzae pv. oryzae PXO99A compared with the genome of strains8004 and RS105 by blastp. There may be unique interactions between 1-DGlcNAc and one or more of these unique proteins in X. oryzae pv. oryzae. Quantitative real-time PCR and the pharmMapper server indicated that proteins involved in cell division could be the targets in PXO99A. This research suggested that specificity of active substance was based on the active group and spatial conformation selection, and these unique proteins could help to reveal the specific mechanism of action of 1-DGlcNAc against PXO99A.

Personal mastery and quality of life in patients with atrial fibrillation after radiofrequency ablation: The mediating role of health promoting behavior.

BACKGROUND: Improving quality of life is vital for patients with atrial fibrillation (AF) after radiofrequency ablation. Quality of life can be affected not only by personal mastery but also by health promoting behavior as previously studied. However, it remains unclear whether health promoting behavior mediates the relationship between personal mastery and quality of life. OBJECTIVES: To explore whether health promoting behavior mediates the relationship between personal mastery and quality of life in patients with AF after radiofrequency ablation. METHODS: A cross-sectional design and convenience sampling were conducted at a tertiary hospital in China. Self-reported questionnaires were used to assess personal mastery, health promoting behavior and quality of life. SPSS and AMOS software were used for statistical analysis. RESULTS: A total of 202 patients with AF after radiofrequency ablation were enrolled (mean age 58.28 ± 12.70 years). The scores for personal mastery and quality of life were 22.52 ± 2.53 points and 62.58 ± 8.59 points, respectively, indicating a limited level. The health promoting behavior exhibited a moderate level, with scores averaging 103.82 ± 8.47 points. There was a positive correlation between the three variables (all P < 0.05). Health promoting behavior played a partial mediating role in the relationship between personal mastery and quality of life in patients with AF after radiofrequency ablation, accounting for 44.79 % of the total effect. CONCLUSIONS: In order to improve quality of life and prognosis, it is necessary to consider enhancing personal mastery and increasing patient compliance with health promoting behavior, which are important ways to improve their quality of life.

A combination method to study the effects of petroleum on soil microbial activity.

TAM III multi-channel calorimetry was applied to study the effect of different concentrations petroleum on soil microbial activity and community. The microbial activities of the soil samples were recorded as power-time curves. The thermokinetic parameters such as microbial growth rate constant k, total heat evolution Q(T), metabolic enthalpy ∆H (met) and mass specific heat rate J(Q/S) were calculated. Results showed that petroleum had a certain extent effects to soil microorganisms. The results indicate that the soil microbial activity was promoted with a petroleum concentration lower than 0.52 % ± 0.24 %, but inhibited with further increase in petroleum.

Restriction of photoinduced twisted intramolecular charge transfer.

An intensive investigation of structure-property relationships in the aggregation-induced enhanced emission (AIEE) of luminescent compounds is essential for the rational design of highly emissive solid-state materials. In the AIEE-active compounds N,N'-bis[3-hydroxy-4-(2'-benzothiazolyl)phenyl]isophthalamide and N,N'-bis[3-hydroxy-4-(2'-benzothiazolyl)phenyl]-5-tert-butylisophthalamide, fast photoinduced twisted intramolecular charge transfer (TICT) of the enol excited state is found to be mainly responsible for the weak emission of their dilute solutions. The photoinduced TICT enol excited state is formed with a greatly distorted configuration, due to the large rotation about the C-N single bond. This facilitates nonradiative TICT decay from the normal enol excited state to the highly twisted enol excited state, rather than proton-transfer decay to the keto excited state. In aggregates, photoinduced nonradiative deactivation of TICT is strongly prohibited, so that excited-state intramolecular proton transfer (ESIPT) becomes the dominant decay, and hence contributes greatly to the subsequent emission enhancement of the keto form. Molecular design and investigation of analogous single-armed compounds further verifies this kind of AIEE mechanism.

Synthesis and evaluation of a novel series of heterocyclic oleanolic acid derivatives with anti-osteoclast formation activity.

Oleanolic acid with anti-bone resorption effect was an active component discovered in a medicinal plant of Achyranthes bidentata. A series of heterocyclic derivatives of oleanolic acid including indole, pyrazine, quinoxaline, quinoline moieties and their natural amino acid amides were synthesized. Their inhibitory activity on the formation of osteoclast-like multinucleated cells (OCLs) and cytotoxicity of the selected derivatives were evaluated. Among the derivatives, compounds 2a and 8a displayed quite a potent activity even at 200 nM. The structure-activity relationships of the derivatives were also discussed.