Transcriptional and Functional Analysis of the Effects of Magnolol: Inhibition of Autolysis and Biofilms in Staphylococcus aureus

BACKGROUND: The targeting of Staphylococcus aureus biofilm structures are now gaining interest as an alternative strategy for developing new types of antimicrobial agents. Magnolol (MOL) shows inhibitory activity against S. aureus biofilms and Triton X-100-induced autolysis in vitro, although there are no data regarding the molecular mechanisms of MOL action in bacteria. METHODOLOGY/PRINCIPAL FINDINGS: The molecular basis of the markedly reduced autolytic phenotype and biofilm inhibition triggered by MOL were explored using transcriptomic analysis, and the transcription of important genes were verified by real-time RT-PCR. The inhibition of autolysis by MOL was evaluated using quantitative bacteriolytic assays and zymographic analysis, and antibiofilm activity assays and confocal laser scanning microscopy were used to elucidate the inhibition of biofilm formation caused by MOL in 20 clinical isolates or standard strains. The reduction in cidA, atl, sle1, and lytN transcript levels following MOL treatment was consistent with the induced expression of their autolytic repressors lrgA, lrgB, arlR, and sarA. MOL generally inhibited or reversed the expression of most of the genes involved in biofilm production. The growth of S. aureus strain ATCC 25923 in the presence of MOL dose-dependently led to decreases in Triton X-100-induced autolysis, extracellular murein hydrolase activity, and the amount of extracellular DNA (eDNA). MOL may impede biofilm formation by reducing the expression of cidA, a murein hydrolase regulator, to inhibit autolysis and eDNA release, or MOL may directly repress biofilm formation. CONCLUSIONS/SIGNIFICANCE: MOL shows in vitro antimicrobial activity against clinical and standard S. aureus strains grown in planktonic and biofilm cultures, suggesting that the structure of MOL may potentially be used as a basis for the development of drugs targeting biofilms

Polar surface structure of oxide nanocrystals revealed with solid-state NMR spectroscopy

Abstract: Compared to nanomaterials exposing nonpolar facets, polar-faceted nanocrystals often exhibit unexpected and interesting properties. The electrostatic instability arising from the intrinsic dipole moments of polar facets, however, leads to different surface configurations in many cases, making it challenging to extract detailed structural information and develop structure-property relations. The widely used electron microscopy techniques are limited because the volumes sampled may not be representative, and they provide little chemical bonding information with low contrast of light elements. With ceria nanocubes exposing (100) facets as an example, here we show that the polar surface structure of oxide nanocrystals can be investigated by applying 17O and 1H solid-state NMR spectroscopy and dynamic nuclear polarization, combined with DFT calculations. Both CeO4-termination reconstructions and hydroxyls are present for surface polarity compensation and their concentrations can be quantified. These results open up new possibilities for investigating the structure and properties of oxide nanostructures with polar facets

Experimental Study on Anchorage Performance of Resin Grout with Steel Segment

With the advantages of large anchoring force and fast anchoring speed, resin cartridge has become the main anchoring means of geotechnical engineering and underground space engineering support. Based on the theoretical analysis, it is clear that adding aggregate can improve the mechanical properties of grout and the bolt-grout interface stress state; the mechanical properties of aggregate are positively correlated with its improvement effect on anchorage performance. By using the numerical simulation method, it is concluded that the addition of steel segments into the resin grout can improve the stiffness of the anchorage system and enhance the energy absorption and antifailure ability of the anchorage system. Relying on the self-developed anchorage mixing device, the effects of steel segment diameter and addition amount on the anchoring force were studied experimentally, and the optimal addition amount of different types of steel segment to improve the maximum anchoring force was determined

mining individual performance indicators in collaborative development using software repositories

Natl Nat Sci Fdn China, Chinese Acad Sci, Inst SoftwareA better understanding of the individual developers performance has been shown to result in benefits such as improved project estimation accuracy and enhanced software quality assurance. However, new challenges of distinguishing the individua

Cultural Landscape Reproduction of Typical Religious Architecture in Qingjiangpu Based on Scene Theory

Scenes are important carriers of cultural expression. Cultural landscapes reveal specific cultural connotations through various scenes, and people understand and give things cultural connotations through scenes. In recent years, new techniques for visualizing cultural landscape heritage have been made possible by the advent of mapping and geographic information technology. The Beijing-Hangzhou Grand Canal’s culture is a “living” cultural legacy. As one of the key links in the canal’s cultural chain, Qingjiangpu is crucial to reproducing its cultural landscape. This paper first discusses the relationship between scene theory and the cultural landscape. Starting from the five elements of scene theory, through the collection of online text data and the corresponding data obtained from questionnaire research, the paper analyzed the scene constructed by the cultural landscape and the urban spirituality embodied by the scene. Through the deep excavation of cultural landscape and its historical context, the theoretical framework of “node-neighbor-city” cultural landscape reproduction is proposed. Taking the ancient city of Qingjiangpu as an example, the cultural landscape has been reproduced at different scales and in different dimensions through various technical means. This study can provide a theoretical basis and practical reference for the research of cultural landscape reproduction

Probabilistic load margin assessment considering forecast error of wind power generation

The increasing integration of wind power in power systems necessitates the probabilistic assessment of various uncertain factors. In operational planning, modeling short-term scale uncertainties, i.e., wind power forecast errors, plays an important role. In this paper, according to the different forecast values, the corresponding probability distributions of wind power forecast errors are developed using a data-driven manner. Then, the polynomial chaos expansion surrogate is developed to facilitate the probabilistic load margin assessment considering wind power forecast errors. The effectiveness of the forecast error model is verified using the historical data of realistic wind power plants. The results show that the probability distributions of forecast errors vary with the level of forecast values. Moreover, the performance of the polynomial chaos expansion surrogate in estimating probabilistic load margin is validated in the IEEE 30-bus system. The results demonstrate that the versatile forecast error distributions significantly impact the characteristics of load margin. Moreover, the polynomial chaos expansion surrogate can accelerate the load margin assessment compared to the Monter Carlo simulation while retaining the same accuracy

A new species of subgenus Homoneura from Northern China, with information of 12 species newly recorded (Diptera: Lauxaniidae: Homoneura)

Shen, Rongrong, Shi, Li, Li, Wenliang, Wang, Junchao (2018): A new species of subgenus Homoneura from Northern China, with information of 12 species newly recorded (Diptera: Lauxaniidae: Homoneura). Zootaxa 4418 (6): 501-525, DOI: https://doi.org/10.11646/zootaxa.4418.6.