哺乳动物嵌合RNAs产生机制:cis-SAGe

嵌合RNAs是指由两个或两个以上独立基因(即亲本基因)融合产生的新RNAs。传统观点认为,嵌合RNAs都是染色体重排的结果。近年来研究发现,相邻基因间的顺式剪接(cis-splicing of adjacent genes,cis-SAGe)也是产生嵌合RNAs的重要机制之一。cis-SAGe是同一条染色体上位置相邻、转录方向相同的基因间发生转录通读,由此产生的初始转录本经过加工,形成了含有两个或多个亲本基因序列的嵌合RNAs。cis-SAGe最初是在肿瘤细胞中被鉴定出来,其在肿瘤发生中的潜在功能引起了研究者的广泛兴趣。随着研究的深入,人们发现cis-SAGe也广泛存在于正常组织中,可能是哺乳动物进化过程中产生新基因的一种重要机制。本文就cis-SAGe的剪接和表达特性、产生机制及其产物的功能等方面进行了综述,以期为人们全面了解cis-SAGe的研究概况及发展趋势提供参考。

Electrostatic self-assembly of MXene and edge-rich CoAl layered double hydroxide on molecular-scale with superhigh volumetric performances

It is highly desirable to design and synthesize two-dimensional nanostructured electrode materials with high electrical conductivity,large electrolyte-accessible surface area and more exposed active sites for energy storage applications.Herein,MXene/Co Al-LDH heterostructure has been prepared through electrostatic ordered hetero-assembly of monolayer MXene and edge-rich Co Al-LDH nanosheets in a faceto-face manner on molecular-scale for supercapacitor applications.Benefiting from the unique structure,strong interfacial interaction and synergistic effects between MXene and Co Al-LDH nanosheets,the electrical conductivity and exposed electrolyte-accessible active sites are significantly enhanced.The asprepared MXene/Co Al-LDH-80%(ML-80)film exhibits high volumetric capacity of 2472 C cm-3 in 3 M KOH electrolyte with high rate capability of 70.6%at 20 A g-1.Notably,to the best of our knowledge,the high volumetric capacity is the highest among other previously reported values for supercapacitors in aqueous electrolytes.Furthermore,our asymmetric supercapacitor device fabricated with ML-80 and MXene/graphene composite as cathode and anode,respectively,exhibits impressive volumetric energy density of 85.4 Wh L-1 with impressive cycling stability of 94.4%retention ratio after 30,000 continuous charge/discharge cycles.

The Equity of Gaokao (National University/College Entrance Examination) in China

Gaokao, the college/university entrance examination, has been playing a decisive role in the access of higher education in China since 1949. This high-stakes examination has received increasing criticisms these years about the contents and forms of the exam. This article briefly examines the development of Gaokao, and focuses on the equity of educational opportunities the examinees can have in different provinces and rural and urban areas, which is the critical way to individual success and the promotion of social mobility. There is inequity of educational opportunities in different provinces as well as the rural and urban areas. The Ministry of Education (MoE) in China has adopted optional examination approaches, inequity, however, arises in them too. Remedial reform is implemented and Gaokao at present is still the effective system while optional system is available.

Artificial intelligence-assisted automatic and index-based microbial single-cell sorting system for One-Cell-One-Tube

Identification,sorting,and sequencing of individual cells directly from in situ samples have great potential for in-depth analysis of the structure and function of microbiomes.In this work,based on an artificial intelligence(AI)-assisted object detection model for cell phenotype screening and a cross-interface contact method for single-cell exporting,we developed an automatic and index-based system called EasySort AUTO,where individual microbial cells are sorted and then packaged in a microdroplet and automatically exported in a precisely indexed,“One-Cell-One-Tube”manner.The target cell is automatically identified based on an AI-assisted object detection model and then mobilized via an optical tweezer for sorting.Then,a crossinterface contact microfluidic printing method that we developed enables the automated transfer of cells from the chip to the tube,which leads to coupling with subsequent single-cell culture or sequencing.The efficiency of the system for single-cell printing is>93%.The throughput of the system for single-cell printing is~120 cells/h.Moreover,>80%of single cells of both yeast and Escherichia coli are culturable,suggesting the superior preservation of cell viability during sorting.Finally,AI-assisted object detection supports automated sorting of target cells with high accuracy from mixed yeast samples,which was validated by downstream single-cell proliferation assays.The automation,index maintenance,and vitality preservation of EasySort AUTO suggest its excellent application potential for single-cell sorting.

Revealing CO_(2)-Fixing SAR11 Bacteria in the Ocean by Raman-Based Single-Cell Metabolic Profiling and Genomics

The majority of marine microbes remain uncultured,which hinders the identification and mining of CO_(2)-fixing genes,pathways,and chassis from the oceans.Here,we investigated CO_(2)-fixing microbes in seawater from the euphotic zone of the Yellow Sea of China by detecting and tracking their ^(13)C-bicarbonate(^(13)C-HCO_(3)^(-))intake via single-cell Raman spectra(SCRS)analysis.The target cells were then isolated by Raman-activated Gravity-driven Encapsulation(RAGE),and their genomes were amplified and sequenced at one-cell resolution.The single-cell metabolism,phenotype and genome are consistent.We identified a notyet-cultured Pelagibacter spp.,which actively assimilates ^(13)C-HCO_(3)^(-),and also possesses most of the genes encoding enzymes of the Calvin-Benson cycle for CO_(2) fixation,a complete gene set for a rhodopsin-based light-harvesting system,and the full genes necessary for carotenoid synthesis.The four proteorhodopsin(PR)genes identified in the Pelagibacter spp.were confirmed by heterologous expression in E.coli.These results suggest that hitherto uncultured Pelagibacter spp.uses light-powered metabolism to contribute to global carbon cycling.