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The piRNA size matters

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National Science Review 2024年第2期11卷 96-98页

作者： jingwen liu Falong Lu State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Chinese Academy of Sciences University of Chinese Academy of Sciences

Small RNAs, including small interfering RNAs(siRNAs), microRNAs(miRNAs) and PIWI-interacting RNAs(piRNAs), serve as pivotal agents in the post-transcriptional regulation of gene expression [1–3]. Among these,piRNAs t...

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中国农业集聚重心与农民收入重心变动研究——基于粮食类农作物空间布局变化的实证检验

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中国农业资源与区划 2017年第12期38卷 64-73页

作者：刘竞文北京文化金来居投资控股有限公司

[目的]考察中国农业集聚的空间分布和变化特征,分析农业集聚重心与农民收入重心两者的相互关系。[方法]文章利用了1985~2015年相关农业产量统计数据,运用了重心分析方法。[结果]1985年以来我国农业空间分布整体呈现南下西进特征,但不同... 详细信息

[目的]考察中国农业集聚的空间分布和变化特征,分析农业集聚重心与农民收入重心两者的相互关系。[方法]文章利用了1985~2015年相关农业产量统计数据,运用了重心分析方法。[结果]1985年以来我国农业空间分布整体呈现南下西进特征,但不同农作物的表现有所不同。谷物1985~2015年整体呈现向东偏北特征,豆类整体呈现向西偏南特征。谷物等主要集中在东北地区,豆类等主要集中在西南地区。而从农民收入重心看,农民收入在空间分布上呈现北上东进特征,2009年后,呈现南上西进特征。农业集聚重心与农民收入重心存在长期协整关系,农业集聚对农民收入产生正向影响。[结论]农业集聚程度与农民收入密切相关,通过农业集约化、专业化生产提高农业集聚程度,可以促进农业发展进而影响农民收入。

关键词：粮食作物农业集聚重心农民收入重心空间分布区域差异

Cloning,expression and characterization of serine palmitoyltransferase(SPT)-like gene subunit(LCB2) from marine Emiliania huxleyi virus(Coccolithovirus)

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Acta Oceanologica Sinica 2012年第6期31卷 127-138页

作者： liu Xuhong ZHENG Tianling CAI Yiqin liu jingwen Bioengineering College of Jimei University Xiamen 361021 China Key Laboratory of MOE for Coast and Wetland Ecosystem Xiamen University Xiamen 361005 China

The authors have isolated and characterized a novel serine palmitoyltransferase （SPT）-like gene in marine Emiliania huxleyi virus （EhV-99B1）. The open-reading frame （ORF） of EhV99BI-SPT encoded a protein of 496 amino acids with a calculated molecular mass of 96 kDa and Ip 6.01. The results of sequence analysis showed that there was about 31% 45% identity in amino acid sequence with other organisms. The maximum likelihood phylogenetic tree suggested that the EhV99B1-SPT gene possibly horizontally transferred from the eukaryote. Hydrophobic profiles of deduced amino acid sequences suggested a hydrophobic, globular and membrane-associated protein with five transmembrane domains （TMDs） motifs. Several potential N-linked glycosylation sites were presented in SPT. These results suggested that EhV99BI-SPT was an integral endoplasmic reticulum membrane protein. Despite lower sequence identity, the secondary and three-dimensional structures predicted showed that the “pocket” structure element composed of 2a-helices and 4β- sheets was the catalytic center of this enzyme, with a typical conserved “TFTKSFG” active site in the N-terminal region and was very close to those of prokaryotic organisms. However, the N-terminal domain of EhV99B1-SPT most closely resembled the LCB2 catalysis subunit and the C-terminal domain most closely resembled the LCBI regulatory subunit of other organisms which together formed a spherical molecule. This “chimera” was highly similar to the prokaryotic homologous SPT. For a functional identification, the EhV99B1-LCB2 subunit gene was expressed in Escherichia coli, which resulted in significant accumulation of new sphingolipid in E. coli cells.

关键词： Emiliania huxleyi virus serine palmitoyltransferase (SPT) clone expressiong andcharacterization

Collusion detector based on G-N algorithm for trust model

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Journal of Systems Engineering and Electronics 2016年第4期27卷 926-935页

作者： Lin Zhang Na Yin jingwen liu Ruchuan Wang College of Computer Nanjing University of Posts and TelecommunicationsNanjing 210003China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nangjing University of Posts and TelecommunicationsNangjing 210003China

In the open network environment, malicious attacks to the trust model have become increasingly serious. Compared with single node attacks, collusion attacks do more harm to the trust model. To solve this problem, a collusion detector based on the GN algorithm for the trust evaluation model is proposed in the open Internet environment. By analyzing the behavioral characteristics of collusion groups, the concept of flatting is defined and the G-N community mining algorithm is used to divide suspicious communities. On this basis, a collusion community detector method is proposed based on the breaking strength of suspicious communities. Simulation results show that the model has high recognition accuracy in identifying collusion nodes, so as to effectively defend against malicious attacks of collusion nodes.

关键词： trust model collusion detector G-N algorithm

A Minireview of Marine Algal Virus-Coccolithoviruses

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Journal of Ocean University of China 2015年第2期14卷 293-300页

作者： liu jingwen XU Miaomiao ZHENG Tianling College of Food and Bioengineering Jimei University Research Center of Food Microbiology and Enzyme Engineering Technology of Fujian Province State Key Laboratory for Marine Environmental Sciences and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem School of Life Sciences Xiamen University

Coccolithophorid is unicellular marine microalgae with a global distribution in temperate and sub-temperate oceanic regions and has the ability to produce ＇the coccoliths＇. It is considered to be the second most productive calcifying organism on earth and becoming an important factor in the global carbonate cycle. Emiliania huxleyi is one of the only two bloom-forming coccolithophores and becomes a species crucial to the study of global biogeochemical cycles and climate modeling. Coccolithoviruse is a recently discovered group of viruses infecting the marine coceolithophorid E. huxleyi. They are a major cause of coceolithophore bloom termination, and DMSP concentration is increasing in the process of viral lysis. Phylogenetic evidences support that some genes are functional both in E. huxleyi and its virus （EhV）. Horizontal gene transfer （HGT） of multiple functionally coupled enzymes occurs in E. huxleyi and its DNA virus EhV has been confirmed, which contributes to the diversification and adaptation of plankton in the oceans and also critically regulates virus-host infection by allowing viruses to control host metabolic pathways for their repli- cation. Therefore, it is of particular interest to understand this host-virus interaction. On this issue, we have made a minireview of coeeolithoviruses focusing on the basic characteristics, phylogenesis, horizontal gene transfer and the interaction between the host and its viruses, as well as its important role in global biogeochemical cycling.

关键词： eoccolithoviruses phylogenetic characteristics virus-host interaction horizontal gene transfer (HGT) global climatechange

Effects of UVB on the expression of proliferating cell nuclear antigen (PCNA) in dinoflagellate Prorocentrum donghaiense Lu

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Acta Oceanologica Sinica 2007年第4期26卷 123-131页

作者： liu jingwen JIAO Nianzhi CAI Huinong HONG Huasheng Bioengineering School of Jimei University Xiamen 361021 China State Key Laboratory of Marine Environmental Sciences of Xiamen University Xiamen 361005 China

PCNA has been considered as a useful marker for the estimation of growth rates of marine phytoplankton at the species level. Since dinoflagellates are noted for having many prokaryotic features in that they are the only eukaryotes to have permanently condensed chromosomes as well as lacking histones and a nucleosome, the sensitivity to UVB radiation and the validity of PCNA as a maker of growth rate in dinoflagellate need to be evaluated. Prorocentrum donghaiense Lu was investigated to valuate the UVB sensitivity in relation to cellular and molecular aspects of PCNA as a growth indicator. The effects of UVB radiation on PCNA were studied using the methods of western blots technology and whole-cell immunoflurescence with one mono-antibody. UVB changed the cell morphology, halted the growth and increased the cell size, even caused cell death to a certain extent after treatment with UVB radiation in P. donghaiense. Compared with the control, treating the algal cultures in exponential phases with UVB radiation for 24 h caused chromatin release and increases in protein levels of PCNA.

关键词： UVB radiation proliferating cell nuclear antigen (PCNA) dinoflagellate Prorocentrum donghaiense Lu

Effects of virus infection on expression of cell cycle regulatory proteins in the unicellular marine algae Emiliania huxleyi

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Acta Oceanologica Sinica 2011年第4期30卷 89-95页

作者： liu jingwen Gunnar Bratbak ZHENG Tianling Runar Thyrhaug Bioengineering College of Jimei University Xiamen 361021 China Department of Microbiology University of Bergen Bergen N-5020 Norway Key Laboratory of MOE for Coast and Wetland Ecosystem School of Life Sciences XiamenUniversity Xiamen 361005 China State Key Laboratory of Marine Environmental Sciences of Xiamen University Xiamen 361005 China

The authors have investigated the biochemical events by which marine algal virus infection induces cell cycle arrest. The key G 2 /M-phase regulatory proteins are analyzed by immunobloting in unicel-lular Emiliania huxleyi,suggesting that virus induced cell cycle arrest is related with virus＇s effect on cyclins and cyclin dependent kinases. E. huxleyi virus（EhV） represses Cdc2/cyclinB complex activity by inhibiting the activity of Cdc2 kinase in a phosphorylation-related manner,blocking host cells G 2 /M checkpoint. Dephosphorylated /inactive Cdc25C combined with up-regulation of Wee1 expression at early infect period appears to be important mechanisms by which EhV represses Cdc2/cyclinB complex activity that is required for entry into M phase. This study has allowed us to confirm that algal virus infection leads to selective activation or inhibition of certain cell-cycle factors,which may play a significant role in establishing a more efficient environment for viral gene expression and DNA replication.

关键词： marine algal virus cell cycle regulators expression Emiliania huxleyi

移动短视频中“土味文化”的话语认知与符号建构研究

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语言与文化研究

语言与文化研究 2025年第1期33卷 258-261页

作者：林蕾柳婧文李佳颖湖南工商大学长沙410205

土味文化是以网络短视频为媒介逐渐流行起来的一种典型网络亚文化,它的发展反映了城乡融合过程中底层青年展示自我的现象,同时也推动了乡村的符号建构进程。基于此,本文对国内外土味文化历史研究进行回顾,通过分析移动短视频中土味文化... 详细信息

土味文化是以网络短视频为媒介逐渐流行起来的一种典型网络亚文化,它的发展反映了城乡融合过程中底层青年展示自我的现象,同时也推动了乡村的符号建构进程。基于此,本文对国内外土味文化历史研究进行回顾,通过分析移动短视频中土味文化内容的特点,追溯移动短视频对于土味文化符号的建构和传播过程,研究土味文化的传播路径多元化,以此发挥土味文化对于加强国民对乡村文化价值认同、传播中国文化的作用。

关键词：短视频土味文化符号建构城乡关系

H3K27me3 shapes DNA methylome by inhibiting UHRF1-mediated H3 ubiquitination

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Science China(Life Sciences) 2022年第9期65卷 1685-1700页

作者： Honglian Zhang Ying liu Yali Xie Yunji Zhu jingwen liu Falong Lu State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental BiologyInnovative Academy of Seed DesignChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

DNA methylation and histone lysine tri-methylation at H3K27(H3K27me3)are two chromatin modifications for transcriptional gene silencing,which play important roles in diverse biological processes,including cell fate determination and cell lineage *** two marks are largely mutually exclusive and target distinct sets of genes in the mammalian ***,how H3K27me3 shapes the DNA methylome remains ***,we report that the loss of H3K27me3 modification leads to increased DNA methylation at previously marked H3K27me3 sites,indicating that H3K27me3 negatively regulates DNA ***-wide analysis of H3 ubiquitination,essential for recruitment and activation of DNA methyltransferase DNMT1,reveals the absence of H3 ubiquitination at H3K27me3 marked ***,loss of H3K27me3 modification induces an increase in H3K18 ubiquitination at the corresponding hyper-methylated ***,we show that H3K27me3 directly inhibits UHRF1-mediated H3 ubiquitination toward nucleosomes in a defined biochemical *** together,our findings reveal a general mechanism for H3K27me3-mediated shaping of the mammalian DNA methylome via modulation of H3 ubiquitination.

关键词： DNA methylation H3K27me3 UHRF1 Polycomb H3 ubiquitination