Search

SETDB2 is a H3K9 histone methyltransferase required for accurate chromosome segregation. Its H3K9 histone methyltransferase activity was reported to be associated with chromosomes during metaphase. Here, we confirm that SETDB2 is required for mitosis and accurate chromosome segregation. However, these functions are independent of its histone methyltransferase activity. Further analysis showed that SETDB2 can interact with BUBR1, and is required for CDC20 binding to BUBR1 and APC/C complex and CYCLIN B1 degradation. The ability of SETDB2 to regulate the binding of CDC20 to BUBR1 or APC/C complex, and stabilization of CYCLIN B1 are also independent of its histone methyltransferase activity. These results suggest that SETDB2 interacts with BUBR1 to promote binding of CDC20 to BUBR1 and APC3, then degrades CYCLIN B1 to ensure accurate chromosome segregation and mitosis, independently of its histone methyltransferase activity. [ABSTRACT FROM AUTHOR]

Biosynthesis methods are considered to be a promising technology for engineering new carbon‐based materials or redesigning the existing ones for specific purposes with the aid of synthetic biology. Lots of biosynthetic processes including metabolism, fermentation, biological mineralization, and gene editing have been adopted to prepare novel carbon‐based materials with exceptional properties that cannot be realized by traditional chemical methods, because microbes evolved to possess special abilities to modulate components/structure of materials. In this review, the recent development on carbon‐based materials prepared via different biosynthesis methods and various microbe factories (such as bacteria, yeasts, fungus, viruses, proteins) are systematically reviewed. The types of biotechniques and the corresponding mechanisms for the synthesis of carbon‐based materials are outlined. This review also focuses on the structural design and compositional engineering of carbon‐based nanostructures (e.g., metals, semiconductors, metal oxides, metal sulfides, phosphates, Mxenes) derived from biotechnology and their applications in electrochemical energy storage devices. Moreover, the relationship of the architecture–composition–electrochemical behavior and performance enhancement mechanism is also deeply discussed and analyzed. Finally, the development perspectives and challenges on the biosynthetic carbons are proposed and may pave a new avenue for rational design of advanced materials for the low‐carbon economy. [ABSTRACT FROM AUTHOR]

Pervaporation has a high potential for separating miscible solutions, particularly azeotropic mixtures. However, mass transfer limitations have long been a common concern in pervaporation device design. Therefore, in this work, we design a static mixer‐based pervaporation device using water–ethanol separation as a model system and further develop computational fluid dynamics tools to investigate systematically all the influencing parameters. In the experiments, we use three‐dimensional printed helical static mixers in the feed liquid channel to enhance mass transfer and implement a Sulzer pervaporation membrane for fast removal of water from ethanol. Using flow and mass‐transfer simulations, we fit the membrane mass transfer coefficient and provide predictive models for optimal process design. Our pervaporation assembly exhibits promising performance and potential toward pervaporation processes for the removal of water from organics and is preferably scaled out by using stackable designs. [ABSTRACT FROM AUTHOR]

Protein folding is a popular topic in the life science. However, due to the limited sampling ability of experiments and simulations, the general folding mechanism is not yet clear to us. In this work, we study the folding of the N‐terminal domain of ribosomal protein L9 (NTL9) in detail by a mixing replica exchange molecular dynamics method. The simulation results are close to previous experimental observations. According to the Markov state model, the folding of the protein follows a nucleation‐condensation path. Moreover, after the comparison to its 39‐residue β‐α‐β motif, we find that the helix at the C‐terminal has a great influence on the folding process of the intact protein, including the nucleation of the key residues in the transition state ensemble and the packing of the hydrophobic residues in the native state. [ABSTRACT FROM AUTHOR]

Reliable conformational sampling and trajectory analysis are always important to the study of the folding or binding mechanisms of biomolecules. Generally, one has to prepare many complicated parameters and follow a lot of steps to obtain the final data. The whole process is too complicated to new users. In this article, we provide a convenient and user‐friendly tool that is compatible to AMBER, called fast sampling and analysis tool (FSATOOL). FSATOOL has some useful features. First and the most important, the whole work is extremely simplified into two steps, one is the fast sampling procedure and the other is the trajectory analysis procedure. Second, it contains several powerful sampling methods for the simulation on graphics process unit, including our previous mixing replica exchange molecular dynamics method. The method combines the advantages of the biased and unbiased simulations. Finally, it extracts the dominant transition pathways automatically from the folding network by Markov state model. Users do not need to do the tedious intermediate steps by hand. To illustrate the usage of FSATOOL in practice, we perform one simulation for a RNA hairpin in explicit solvent. All the results are presented. © 2019 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Constructing a free energy landscape for a large molecule is difficult. One has to use either a high temperature or a strong driving force to enhance the sampling on the free energy barriers. In this work, we propose a mixed method that combines these two kinds of acceleration strategies into one simulation. First, it applies an adaptive biasing potential to some replicas of the molecule. These replicas are particularly accelerated in a collective variable space. Second, it places some unbiased and exchangeable replicas at various temperature levels. These replicas generate unbiased sampling data in the canonical ensemble. To improve the sampling efficiency, biased replicas transfer their state variables to the unbiased replicas after equilibrium by Monte Carlo trial moves. In comparison to previous integrated methods, it is more convenient for users. It does not need an initial reference biasing potential to guide the sampling of the molecule. And it is also unnecessary to insert many replicas for the requirement of passing the free energy barriers. The free energy calculation is accomplished in a single stage. It samples the data as fast as a biased simulation and it processes the data as simple as an unbiased simulation. The method provides a minimalist approach to the construction of the free energy landscape. © 2019 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Cytochrome P450s (CYPs) are known to play a major role in metabolizing a wide range compounds. CYP6FU1 has been found to be over‐expressed in a deltamethrin‐resistant strain of Laodelphax striatellus. This study was conducted to express CYP6FU1 in Sf9 cells as a recombinant protein, to confirm its ability to degrade deltamethrin, chlorpyrifos, imidacloprid and traditional P450 probing substrates. RESULTS: Carbon monoxide difference spectrum analysis indicated that the intact CYP6FU1 protein was expressed in insect Sf9 cells. Catalytic activity tests with four traditional P450 probing substrates revealed that the expressed CYP6FU1 preferentially metabolized p‐nitroanisole and ethoxyresorufin, but not ethoxycoumarin and luciferin‐HEGE. The enzyme kinetic parameters were tested using p‐nitroanisole. The michaelis constant (Km) and catalytic constant (Kcat) values were 17.51 ± 4.29 µ m and 0.218 ± 0.001 pmol min−1 mg−1 protein, respectively. Furthermore, CYP6FU1 activity for degradation of insecticides was tested by measuring substrate depletion and metabolite formation. The chromatogram analysis showed obvious nicotinamide‐adenine dinucleotide phosphate (NADPH)‐dependent depletion of deltamethrin, and formation of the unknown metabolite. Mass spectra and the molecular docking model showed that the metabolite was 4‐hydroxy‐deltamethrin. However, the recombinant CYP6FU1 could not metabolize imidacloprid and chlorpyrifos. CONCLUSION: These results confirmed that the over‐expressed CYP6FU1 contributes to deltamethrin resistance in L. striatellus, and p‐nitroanisole might be a potential diagnostic probe for deltamethrin metabolic resistance detection and monitoring. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Cytochrome P450s are associated with the metabolising of a wide range of compounds, including insecticides. CYP353D1v2 has been found to be overexpressed in an imidacloprid-resistant strain of Laodelphax striatellus. Thus, this study was conducted to express CYP353D1v2 in Sf9 cells as a recombinant protein, to assess its ability to metabolise imidacloprid. RESULTS Western blot and carbon monoxide difference spectrum analysis indicated that the intact CYP353D1v2 protein had been successfully expressed in Sf9 insect cells. Catalytic activity tests with four traditional P450-activity-probing substrates found that the expressed CYP353D1v2 preferentially metabolised p-nitroanisole, ethoxycoumarin and ethoxyresorufin with specific activities of 32.70, 0.317 and 1.22 pmol min−1 pmol−1 protein respectively, but no activity to luciferin-H EGE. The enzyme activity for degrading imidacloprid was tested by measuring substrate depletion and formation of the metabolite. Kinetic parameters for imidacloprid were Km 5.99 ± 0.95 µ m and kcat 0.03 ± 0.0004 min−1. The chromatogram analysis showed clearly the NADPH-dependent depletion of imidacloprid and the formation of an unknown metabolite. The UPLC-MS mass spectrum demonstrated that the metabolite was an oxidative product of imidacloprid, 5-hydroxy-imidacloprid. CONCLUSION These results suggest that CYP353D1v2 in L. striatellus is capable of degrading imidacloprid, and that enzyme activity can be evaluated well only by some traditional probing substrates. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Zhang H. Discourse change and policy development in social assistance in China Since the introduction of a new social assistance programme in urban China, the state was eventually able to expand the programme to rural areas as a further step towards integrating the development of social assistance in urban and rural areas. This article argues that the development of social assistance in China can be explained by the change of discourse among the officials and the elites in central government. The discourse on social assistance can be conceptualised in three periods: the urban-first discourse (1999-2003); the discourse debate (2003-2007); and the urban-rural integration discourse (2007-present). Through scrutinising specific discourses and the policy development of social assistance in these three periods, it appears that in company with the change in the discourse process, rural social assistance was developed rapidly in order to construct an integrated social assistance system. The article concludes that discourse plays a significant role in Chinese social assistance policy development. [ABSTRACT FROM AUTHOR]