The expression of FtsZ and its localization in Spirulina platensis

FtsZ是最早被鉴定出与真核微管蛋白类似的原核骨架蛋白，广泛存在于原核生物中，在植物中也有发现。它最先从大肠杆菌温度敏感型突变体中分离得到，当它突变后杆状大肠杆菌会停止分裂变成长丝状菌体。FtsZ在细胞中部分裂位点形成一个Z环，接着细胞缢缩内陷分裂成两个子细胞。 螺旋藻在不良环境下会从正常螺旋形转变为不同螺旋度的螺旋形甚至直线形。本实验以钝顶螺旋藻（Spirulinaplatensis）FACHB869FtsZ为出发点，研究其功能及与螺旋藻形态建成的关系。我们克隆了钝顶螺旋藻FACHB869的ftsZ基因全序列并构建了表达载体pET28a–ftsZ和荧光融合表达载体pGFPxm-ftsZ。在...FtsZ is a prokaryotic homologue of eukaryotic tubulins. It appears to be universal in eubacteria and archaebacteria and has also been identified in plants. ftsZ has been identified as temperature-sensitive mutants(fts) in Escherichia coli. FtsZ mutants can grow for a time at the non-permissive temperature, but septation is blocked, leading to long filamentous cells. FtsZ forms Z-rings at the centr...学位：理学硕士院系专业：生命科学学院生物学系_水生生物学学号：2162007115206

Expression and Localization of FtsZ from Spirulina platensis in Escherichia coli

fTSz是与真核微管蛋白类似的原核骨架蛋白,能在细胞分裂位点聚合组装成环状结构而调控细胞分裂过程。为了研究钝顶螺旋藻(SPIrulInA PlATEnSIS)fTSz蛋白的功能,构建了钝顶螺旋藻fTSz与绿色荧光蛋白gfP融合表达的质粒,并在大肠杆菌中进行了表达和定位研究,结果发现,表达融合蛋白gfP-fTSz的大肠杆菌细胞由短杆状变为长丝状,且菌丝体长度与融合蛋白的表达量呈正比。在荧光显微镜下观察到融合蛋白gfP-fTSz在长丝状体细菌中呈有规律的点状分布,这说明fTSz蛋白功能高度保守,钝顶螺旋藻fTSz蛋白能识别大肠杆菌分裂位点并装配成环状结构调控大肠杆菌细胞分裂,fTSz蛋白的过量表达能抑制大肠杆菌正常的细胞分裂而导致长丝状体细胞的形成。Prokaryotic cytoskeletal protein FtsZ,a microtubule homolog,assembles into a compact circular structure at the mid-cell and plays an important role in cytokinesis.To explore the function of FtsZ in Spirulina platensis morphogenesis,we cloned the ftsZ gene from S.platensis and constructed its fusion tag of GFP expression plasmid pGFP-FtsZ.The recombined expression vector was transformed to Escherichia coli BL21.Western blot analysis showed that the GFP-FtsZ fusion gene was successfully expressed in the transformant.The transformed bacteria that expressed the GFP-FtsZ protein changed from normal short-rod shapes and formed long filaments.The length of the filamentation cells was proportional to the expression amount of FtsZ in cells.Regular-dot distribution of the GFP-FtsZ fusion protein in transformed bacteria was observed by fluorescent light microscopy.The data demonstrated that FtsZ was a highly conserved functional protein.The FtsZ of S.platensis assembled the complete cytokinesis apparatus and formed a Z-ring structure at the future division site to regulate cell division in E.coli.The overexpression of FtsZ blocked the normal cell cycle and led to cell filamentation.国家自然科学基金资助项目(30571446); 福建省自然科学基金资助项目(2009J01193

THE FUNCTION OF FTSZ IN MORPHOGENESIS OF SPIRULINA PLATENSIS

作者简介:邹路阳(1985—), 男, 四川绵阳人; 硕士研究生; 主要从事海洋分子生物学的研究。E-mail: [email protected]通讯作者:徐虹(1973—), 女, 湖南常德人; 博士, 副教授; E-mail: [email protected][中文文摘]为了研究细胞骨架蛋白FtsZ在螺旋藻形态建成中的作用,通过PCR克隆了ftsZ基因并进行原核表达,对表达的融合蛋白进行了纯化。通过免疫小鼠制备了FtsZ的多克隆抗体。分别用Western blot和免疫荧光技术检测螺旋藻不同形态藻丝体中ftsZ的表达和定位。结果表明,在两株不同螺旋藻Spirulina platensis FACHB869和FACHB882中,ftsZ在直线形藻丝体中的表达量都高于螺旋形藻丝体。免疫荧光定位结果显示,FtsZ蛋白在藻细胞中呈环状分布于细胞膜上,且这种环状结构在直线形藻丝体中排列较密而在螺旋形藻丝体中排列疏松。ftsZ在不同形态藻丝体中的表达量和细胞定位差异说明,细胞骨架蛋白FtsZ可能通过改变细胞刚性而参与螺旋藻形态建成。 [英文文摘] To explore the function of prokaryotic cytoskeleton protein FtsZ in morphogenesis of Spirulina platensis, the gene encoding FtsZ was cloned into pET-28a vector and highly expressed in E. coli BL21. The target protein purified by affinity chromatography was used to immunize mice to prepare polyclonal antibodies. The differences in expression and localization of FtsZ between linear and spiral forms of Spirulina platensis were determined by western blot and immunofluorescence respectively. Both the results of western blotting from two strains of Spirulian plantensis showed that the expression level of Ftsz in linear algal trichomes was higher than that of spiral forms. FtsZ were localized under¬neath the cell membrane at the future division site, forming a ring-like structure known as the Z-ring. The Z-ring dis¬tributed more tightly in linear forms than that in spiral forms. The differences in expression and localization of FtsZ between linear and spiral forms of Spirulina platensis mean that cytoskeleton FtsZ probably plays an important role in morphogenesis of Spirulina platensis.国家自然科学基金(No. 30571446); 福建省自然科学基金(No. 2009J01193)资

Anxiety，depression and insomnia in pregnant women during the COVID － 19 epidemic in Beijing

目的:评估新冠肺炎流行期间孕妇的焦虑抑郁症状与睡眠问题及其相关因素。方法:2020年2月28日-4月26日,通过网络问卷平台调查北京四家助产机构就诊的885例孕妇的焦虑抑郁症状及睡眠问题。采用广泛焦虑量表(GAD-7)评估焦虑症状,采用患者健康问卷抑郁症状群量表(PHQ-9)评估抑郁症状,采用失眠严重程度指数量表(ISI)评估失眠症状。结果:本样本中焦虑症状、抑郁症状及失眠症状检出率分别为12.2%,24.6%和13.6%。缺少照顾(OR=1.73)、有分娩担忧(OR=3.95)及心理弹性差(OR=4.57)是焦虑症状的危险因素;家庭收入高(OR=1.94)、有分娩担忧(OR=2.39)及心理弹性差(OR=3.04)是抑郁症状的危险因素;除已婚外其他婚姻状况(OR=4.95)、孕周较长(13～27周,OR=2.03;28周及以上,OR=2.13)、有躯体疾病史(OR=1.77)、存在分娩担忧(OR=2.78)及心理弹性差(OR=1.67)是失眠症状危险因素。结论:新冠肺炎流行期间北京市孕妇焦虑症状、抑郁症状及失眠症状常见,尤其是存在分娩担忧及心理弹性差的孕妇。</p

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies