Crystal Structure of the Human Short Coiled Coil Protein and Insights into SCOC-FEZ1 Complex Formation

The short coiled coil protein (SCOC) forms a complex with fasciculation and elongation protein zeta 1 (FEZ1). This complex is involved in autophagy regulation. We determined the crystal structure of the coiled coil domain of human SCOC at 2.7 Å resolution. SCOC forms a parallel left handed coiled coil dimer. We observed two distinct dimers in the crystal structure, which shows that SCOC is conformationally flexible. This plasticity is due to the high incidence of polar and charged residues at the core a/d-heptad positions. We prepared two double mutants, where these core residues were mutated to either leucines or valines (E93V/K97L and N125L/N132V). These mutations led to a dramatic increase in stability and change of oligomerisation state. The oligomerisation state of the mutants was characterized by multi-angle laser light scattering and native mass spectrometry measurements. The E93V/K97 mutant forms a trimer and the N125L/N132V mutant is a tetramer. We further demonstrate that SCOC forms a stable homogeneous complex with the coiled coil domain of FEZ1. SCOC dimerization and the SCOC surface residue R117 are important for this interaction.     

医学生实习中外科基本操作常犯错误及对策分析

目的：探讨医学生临床实习中在基本操作上常犯的错误,并对此提出建议和纠正措施,旨在进一步提高临床带教水平及临床教学质量。方法i总结我院临床医学专业实习生进行常见的外科临床基本操作考核成绩的情况,对错误类型等进行统计并提出合理的解决措施。结果：共考察学生90名,其中外科换药方法欠佳者22人（24．4％）,消毒铺巾存在问题24人（26．6％）,缝合存在问题32人（35．5％）,打结存在问题38（42．2％）人,拆线存在问题19（21．1％）人。结论：加强医学生外科实习期间的无菌观念培养及强化手术基本操作是临床教学的重要环节。     

Prediction of thermodynamically reversible hydrogen storage reactions utilizing Ca–M(M = Li, Na, K)–B–H systems: a first-principles study

Calcium borohydride is a potential candidate for onboard hydrogen storage because it has a high gravimetric capacity (11.5 wt.%) and a high volumetric hydrogen content (～130 kg m^?3). Unfortunately, calcium borohydride suffers from the drawback of having very strongly bound hydrogen. In this study, Ca(BH₄)₂ was predicted to form a destabilized system when it was mixed with LiBH₄, NaBH₄, or KBH₄. The release of hydrogen from Ca(BH₄)₂ was predicted to proceed via two competing reaction pathways (leading to CaB₆ and CaH₂ or CaB₁₂H₁₂ and CaH₂) that were found to have almost equal free energies. Using a set of recently developed theoretical methods derived from first principles, we predicted five new hydrogen storage reactions that are among the most attractive of those presently known. These combine high gravimetric densities (>6.0 wt.% H₂) with have low enthalpies [approximately 35 kJ/(mol^?1 H₂)] and are thermodynamically reversible at low pressure within the target window for onboard storage that is actively being considered for hydrogen storage applications. Thus, the first-principles theoretical design of new materials for energy storage in future research appears to be possible.

Chemical Composition and Antimicrobial Activity of the Essential Oil from the Edible Aromatic Plant Aristolochia delavayi

The essential oil obtained by hydrodistillation from the aerial parts of Aristolochia delavayi Franch. (Aristolochiaceae), a unique edible aromatic plant consumed by the Nakhi (Naxi) people in Yunnan, China, was investigated using GC/MS analysis. In total, 95 components, representing more than 95% of the oil composition, were identified, and the main constituents found were (E)‐dec‐2‐enal (52.0%), (E)‐dodec‐2‐enal (6.8%), dodecanal (3.35%), heptanal (2.88%), and decanal (2.63%). The essential oil showed strong inhibitory activity (96% reduction) of the production of bacterial volatile sulfide compounds (VSC) by Klebsiella pneumoniae, an effect that was comparable with that of the reference compound citral (91% reduction). Moreover, the antimicrobial activity of the essential oil and the isolated major compound against eight bacterial and six fungal strains were evaluated. The essential oil showed significant antibacterial activity against Providencia stuartii and Escherichia coli, with minimal inhibitory concentrations (MIC) ranging from 3.9 to 62.5 μg/ml. The oil also showed strong inhibitory activity against the fungal strains Trichophyton ajelloi, Trichophyton terrestre, Candida glabrata, Candida guilliermondii, and Cryptococcus neoformans, with MIC values ranging from 3.9 to 31.25 μg/ml, while (E)‐dec‐2‐enal presented a lower antifungal activity than the essential oil.     

Overproduction of a truncated poly (vinyl alcohol) dehydrogenase in recombinant Pichia pastoris by low-temperature induction strategy and related mechanism analysis

Based on the N-terminal sequencing of poly (vinyl alcohol) dehydrogenase (PVADH), a 1,644-bp gene encoding a truncated PVADH (tPVADH) was amplified using the synthetic gene (GenBank accession No. JQ235753) as a template, and was further transformed into Pichia pastoris GS115 with the vector pPIC9K. The maximal tPVADH activity reached 546 U/mL in shake flask. The influence of methanol concentration and induction temperature on tPVADH production was further investigated in 3-L bioreactor. When the methanol concentration and induction temperature were controlled at 15 g/L and 22 °C, respectively, the maximal tPVADH activity reached 8,464 U/mL, which was nearly 10 times that of mature PVADH expressed under the same condition and was the highest level ever reported. The reason responsible for the significant improvement of tPVADH production at low induction temperature was explored in terms of cell viability, extracellular proteases activity, and alcohol oxidase activity.     

Genome-wide identification and characterisation of F-box family in maize

F-box-containing proteins, as the key components of the protein degradation machinery, are widely distributed in higher plants and are considered as one of the largest known families of regulatory proteins. The F-box protein family plays a crucial role in plant growth and development and in response to biotic and abiotic stresses. However, systematic analysis of the F-box family in maize (Zea mays) has not been reported yet. In this paper, we identified and characterised the maize F-box genes in a genome-wide scale, including phylogenetic analysis, chromosome distribution, gene structure, promoter analysis and gene expression profiles. A total of 359 F-box genes were identified and divided into 15 subgroups by phylogenetic analysis. The F-box domain was relatively conserved, whereas additional motifs outside the F-box domain may indicate the functional diversification of maize F-box genes. These genes were unevenly distributed in ten maize chromosomes, suggesting that they expanded in the maize genome because of tandem and segmental duplication events. The expression profiles suggested that the maize F-box genes had temporal and spatial expression patterns. Putative cis-acting regulatory DNA elements involved in abiotic stresses were observed in maize F-box gene promoters. The gene expression profiles under abiotic stresses also suggested that some genes participated in stress responsive pathways. Furthermore, ten genes were chosen for quantitative real-time PCR analysis under drought stress and the results were consistent with the microarray data. This study has produced a comparative genomics analysis of the maize ZmFBX gene family that can be used in further studies to uncover their roles in maize growth and development.     

Large Scale Fabrication of Gold Nano-Structured Substrates Via High Temperature Annealing and Their Direct Use for the LSPR Detection of Atrazine

The present work is reporting on the fabrication of localized surface plasmonic resonant (LSPR) gold nano-structures on glass substrate by using different high annealing temperatures (500 °C, 550 °C, 600 °C) of initially created semi-continue gold films (2 nm and 5 nm) by the electron beam evaporation technique. Interestingly, well-defined gold nano-structures were also obtained from continuous 8 nm evaporated gold film - known as the value above gold percolated thickness - once exposed to high temperatures. The surface morphology and plasmonic spectroscopy of “annealed” nano-structures were controlled by key experimental parameters such as evaporated film thickness and annealing temperature. By using scanning electron microscopy (SEM) characterization of annealed surface it was noticed that the size and inter-particle distance between nano-structures were highly dependent on the evaporated thin film thickness, while the nanoparticle shape evolution was mainly affected by the employed annealing temperature. Due to the well-controlled morphology of gold nano-particles, prominent and stable LSPR spectra were observed with good plasmon resonance tunability from 546 nm to 780 nm that recommend the developed protocol as a robust alternative to fabricate large scale LSPR surface. An example of a LSPR-immunosensor is reported. Thus, the monoclonal anti-atrazine antibodies immobilizion on the “annealed” gold nano-structures, as well as the specific antigen (atrazine) recognition were monitored as variations of the resonance wavelength shifts and optical density changes in the extinction measurements.     

Expression and epigenetic regulation of angiogenesis-related factors during dormancy and recurrent growth of ovarian carcinoma

The initiation of angiogenesis can mark the transition from tumor dormancy to active growth and recurrence. Mechanisms that regulate recurrence in human cancers are poorly understood, in part because of the absence of relevant models. The induction of ARHI (DIRAS3) induces dormancy and autophagy in human ovarian cancer xenografts but produces autophagic cell death in culture. The addition of VEGF to cultures maintains the viability of dormant autophagic cancer cells, thereby permitting active growth when ARHI is downregulated, which mimics the “recurrence” of growth in xenografts. Two inducible ovarian cancer cell lines, SKOv3-ARHI and Hey-ARHI, were used. The expression level of angiogenesis factors was evaluated by real-time PCR, immunohistochemistry, immunocytochemistry and western blot; their epigenetic regulation was measured by bisulfite sequencing and chromatin immunoprecipitation. Six of the 15 angiogenesis factors were upregulated in dormant cancer cells (tissue inhibitor of metalloproteinases-3, TIMP3; thrombospondin-1, TSP1; angiopoietin-1; angiopoietin-2; angiopoietin-4; E-cadherin, CDH1). We found that TIMP3 and CDH1 expression was regulated epigenetically and was related inversely to the DNA methylation of their promoters in cell cultures and in xenografts. Increased H3K9 acetylation was associated with higher TIMP3 expression in dormant SKOv3-ARHI cells, while decreased H3K27me3 resulted in the upregulation of TIMP3 in dormant Hey-ARHI cells. Elevated CDH1 expression during dormancy was associated with an increase in both H3K4me3 and H3K9Ac in two cell lines. CpG demethylating agents and/or histone deacetylase inhibitors inhibited the re-growth of dormant cancer cells, which was associated with the re-expression of anti-angiogenic genes. The expression of the anti-angiogenic genes TIMP3 and CDH1 is elevated during dormancy and is reduced during the transition to active growth by changes in DNA methylation and histone modification.     

Hepatitis B Virus Induces IL-23 Production in Antigen Presenting Cells and Causes Liver Damage via the IL-23/IL-17 Axis

IL-23 regulates myriad processes in the innate and adaptive immune systems, and is a critical mediator of the proinflammatory effects exerted by Th17 cells in many diseases. In this study, we investigated whether and how hepatitis B virus (HBV) causes liver damage directly through the IL-23 signaling pathway. In biopsied liver tissues from HBV-infected patients, expression of both IL-23 and IL-23R was remarkably elevated. In vivo observations also indicated that the main sources of IL-23 were myeloid dendritic cells (mDCs) and macrophages. Analysis of in vitro differentiated immature DCs and macrophages isolated from healthy donors revealed that the HBV surface antigen (HBsAg) efficiently induces IL-23 secretion in a mannose receptor (MR)-dependent manner. Culture with an endosomal acidification inhibitor and the dynamin inhibitor showed that, upon binding to the MR, the HBsAg is taken up by mDCs and macrophages through an endocytosis mechanism. In contrast, although the HBV core antigen (HBcAg) can also stimulate IL-23 secretion from mDCs, the process was MR- and endocytosis-independent. In addition, IL-23 was shown to be indispensible for HBsAg-stimulated differentiation of naïve CD4⁺ T cells into Th17 cells, which were determined to be the primary source of IL-17 in HBV-infected livers. The cognate receptor, IL-17R, was found to exist on the hepatic stellate cells and mDCs, both of which might represent the potential target cells of IL-17 in hepatitis B disease. These data provide novel insights into a yet unrecognized mechanism of HBV-induced hepatitis, by which increases in IL-23 expression, through an MR/endocytosis-dependent or -independent manner, produce liver damage through the IL-23/IL-17 axis.