A yeast surface display platform for plant hormone receptors: Toward directed evolution of new biosensors

Small-molecule biosensors have major applications in biotechnology and medicine but remain difficult to engineer. Plant hormone receptors represent an attractive platform for engineering such biosensors because their chemically induced dimerization architectures naturally decouple small-molecule sensing and sensor actuation. Rapid biosensor engineering will require quantitative high-throughput screening methods. Here we develop a yeast surface display (YSD) platform for the PYR1/HAB1 abscisic acid sensor of Arabidopsis thaliana. We extensively optimized PYR1 surface display, HAB1 purification, and binding reaction conditions. Our system reproduces previous results with wild-type and engineered receptors, and a mathematical analysis of the PYR1/HAB1 system allows us to infer all binding constants. Critically, we find that a previously engineered PYR1 receptor with altered ligand specificity binds HAB1 with identical affinity, suggesting that substantial reengineering of the PYR1 binding pocket does not compromise sensor actuation. This YSD platform for A. thaliana PYR1/HAB1 will facilitate future biosensor engineering efforts.     

High molecular weight poly(butylene terephthalate-co-butylene 2,5-furan dicarboxylate) copolyesters: From synthesis to thermomechanical and barrier properties

Poly(butylene terephthalate-co-butylene 2,5-furandicarboxylate) copolyesters (PBTFs) were synthesized from 1,4-butanediol, dimethyl terephthalate (DMT), and 2,5-furandicarboxylic acid (FDCA) by a two-step polymerization method. Their chemical structures were confirmed by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and carbon nuclear magnetic resonance before thermal properties were explored with differential scanning calorimeter and thermogravimetric analyzer. Results showed that PBTFs changed from semi-crystalline to completely amorphous when the content of FDCA unit was increased to 45 mol% at first, and then became crystallographic again with the further increment of FDCA unit to 75 mol%. For their mechanical properties, the tensile modulus and strength showed the similar trend, decreasing firstly and then increasing later. Their barrier to carbon dioxide and oxygen became better with the increasing of furan content due to the rigidity and higher polarity of furan ring. The performance of PBTFs copolyesters was investigated clearly, and the relative content of FDCA and DMT can be adjusted to satisfy different performance requirements.     

Dynamic Stabilization of DNA Assembly by Using Pyrrole-Imidazole Polyamide

We used N-methylpyrrole (Py)-N-methylimidazole-(Im) polyamide as an exogenous agent to modulate the formation of DNA assemblies at specific double-stranded sequences. The concept was demonstrated on the hybridization chain reaction that forms linear DNA. Through a series of melting curve analyses, we demonstrated that the binding of Py−Im polyamide positively influenced both the HCR initiation and elongation steps. In particular, Py−Im polyamide was found to drastically stabilize the DNA duplex such that its thermal stability approached that of an equivalent hairpin structure. Also, the polyamide served as an anchor between hairpin pairs in the HCR assembly, thus improving the originally weak interstrand stability. We hope that these proof-of-concept results can inspire future use of Py−Im polyamide as a molecular tool to modulate the formation of DNA assemblies.     

两性霉素B补料分批发酵工艺优化

为大幅提高产两性霉素B菌株的发酵产抗水平,对外源性短链脂肪酸类前体物质及其添加时机、添加量进行优化,得到了两性霉素B补料分批发酵工艺,即在产两性霉素B菌株发酵培养24～56 h左右,一次性补入2～4 g·L~(-1)(以发酵液总量计)的丙酸钠。该工艺解决了两性霉素B生物合成途径中内酯环形成的关键性因素,大幅提高了产两性霉素B菌株的发酵产抗水平。经15 t生产罐验证,最终实现了连续3批平均放罐效价达10 977μg·mL~(-1)的发酵产抗水平,与采用原发酵工艺的生产罐批相比,放罐效价提高了39.4%。     

Dependence of Lamellar Eutectic Growth with Convection on Boundary Conditions and Geometric Confinement: A Phase-Field Lattice-Boltzmann Study

Metallurgical and Materials Transactions B - Simulating eutectic growth with convection is challenging because of the enormous computing demand resulting from the required domain size compared with...     

某型导弹飞行航迹特效的设计与实现

介绍了某型导弹仿真系统中尾焰、击中目标等特效的生成。说明了在粒子系统和纹理映射理论的基础上,利用OpenGL强大的纹理和融合功能,实现导弹尾迹特效。仿真结果表明,这种方法能够实现对特效的控制,有较大的灵活性,对在Vega环境中应用粒子系统提供了一个方法。     

基于GIS的雷达远程显示系统的设计与实现

将GIS应用在雷达远程显示系统中。运用组件式GIS开发模式,设计了具有串行数据通信、网络数据通信、目标数据定位、属性查询、地理分析等功能的GIS应用软件。系统的研制打破了传统雷达信息显示方式的局限性,实现了雷达信息与GIS的有机结合,给指挥人员的决策带来极大的方便。     

The mitochondrial genome from the thermal dimorphic fungus Paracoccidioides brasiliensis

We present here the sequence of the mitochondrial DNA of the pathogenic thermodimorphic fungus Paracoccidioides brasiliensis, agent of an endemic disease in most South American countries. The sequenced genome has 71 334 bp and is organized as a circular molecule with two gaps of unknown size flanking the middle exon of the nad5 gene. We located genes coding for the three subunits of the ATP synthase (atp6, atp8 and atp9), the apocytochrome b (cob), three subunits of the cytochrome c oxidase enzyme complex (cox1, cox2 and cox3), seven subunits of the reduced nicotinamide adenine dinucleotide ubiquinone oxidoreductase (nad1, nad2, nad3, nad4, nad5, nad6 and nad4L) and the large (rnl) and small (rns) subunits of ribosomal RNA. Two maturases and a ribosomal protein (rms5) are located inside introns. Twenty-five tRNAs were identified with acceptors for all 20 amino acids. Seven polypurine/polypyrimidine tracts (140-240 bp) have been found in this genome. All genes are in the same orientation over the genome, while their order is closest to the mitochondrial genomes from Penicillium marneffei and Aspergillus nidulans.     

“美无非是一个关于幸福的承诺”——RCR建筑事务所的贡献

<正>("美无非是一个关于幸福的承诺"——司汤达,《论爱情》,第17章,1822年)对于建筑界的大奖——普利茨克奖在2017年花落RCR建筑事务所的消息,世界各地的出版物不约而同地评论:实乃意外。此前,媒体大多预测着一个闪亮的大师名号摘得荣耀,却只获知了一个干巴巴的首字母缩略词——RCR——一个低调的加泰罗尼亚建筑事务所。该事务所由三名建筑师所组成:拉法尔·阿兰达(Rafael Aranda).     

Optimization of alcohol‐free beer production by lager and cachaça yeast strains using response surface methodology

Alcohol‐free beers (AFBs) are an attractive segment of the beer market both for the brewing industry and for consumers. While AFBs produced by arrested/limited fermentation often suffer from a lack of volatile compounds, beer flavour can be improved by yeast selection and optimization of fermentation conditions. The yeast selection strategy was demonstrated by comparing traditional lager yeast with selected cachaça yeast strains. Correspondingly, response surface methodology was used to enhance the formation of the flavour‐active volatile compounds by optimization of the fermentation conditions (original wort extract, fermentation temperature, pitching rate). Statistical analysis of the experimental data revealed the relative significance of process variables and their interactions. The developed quadratic model describing the responses of total esters and higher alcohols to changes in process variables was used to predict the ideal fermentation conditions in terms of flavour formation. The predicted conditions were experimentally verified and alternative strategies of AFB production are suggested. Copyright © 2016 The Institute of Brewing & Distilling