抗菌肽CM4组分对离体癌细胞的影响

抗菌肽ＣＭ４作用Ｈｅｌａ细胞骨架后,细胞骨架由最初的完整微管系统卷缩成不规则网架,细胞贴壁性下降,形态不能正常维持．荧光标记抗菌肽ＣＭ４组分作用ＳＰ２／０显微观察结果发现,在早期细胞表面和胞内分布有不均匀的高强度荧光标记物,进一步作用可使癌细胞膜破裂,内容物外泄,最终导致细胞死亡     

二（四甲基环戊二烯基）四羰基二铁的合成及反应

四甲基环戊二烯与五羰湛铁在二甲苯中加热回流６ｈ，即生成标题化合物１，１与碘在氯仿中反应生成Ｆｅ－Ｆｅ键断裂在铁碘化物（Ｃ５ＨＭｅ４）Ｆｅ（ＣＯ）２Ｉ，２，１与氯化汞反应生成Ｆｅ－Ｆｅ键断裂的铁氯汞化物（Ｃ５ＨＭｅ４）Ｆｅ（ＣＯ）２ＨｇＣｌ３和铁氯化物（Ｃ５ＨＭｅ４）Ｆｅ（ＣＯ）２Ｃｌ４．１与氯化亚锡反应仅分离到铁氯化物４．以元素分析，ＩＲ和ＨＮＭＲ谱表征化合物１～４的结构。     

研究聚ADP核糖基化作用与细胞恶变关系的双基因真核表达重…

本文将聚ＡＤＰ核糖聚合酶基因１．４ｋｂ部分序列反向插入真核表达载体ｐＭＡＭｎｅｏ和ｐＳＭＧ中，同时１２位密码子突变的活化ｒａｓ癌基因也一同克隆到上述载体中，从而获得具有不同真核基因筛选标记的双基因真核表达重组ｐＭＡＭｎｅｏ－Ｃｌ．４－Ｔ２４，ｐＭＡＭｎｅｏ－Ｃｌ．４－ａｒＴ２４，及ｐＳＭＧ－Ｃｌ．４－Ｔ２４，上述质粒的构建成功为研究聚ＡＤＰ核糖基化作用与细胞恶变的关系提供了一种新的分子模型。     

二（四甲基环成二烯基）四羰基二铁的合成及反应

四甲基环戊二烯与五羰基铁在二甲苯中加热回流６ｈ，即生成标题化合物１，１与碘在氯仿中反应生成Ｆｅ－Ｆｅ键断裂的铁碘化物（Ｃ５ＨＭｅ４）Ｆｅ（ＣＯ）２Ｉ２，１与氯化汞反应生成Ｆｅ－Ｆｅ键断裂的铁氯汞化物（Ｃ５ＨＭｅ４）Ｆｅ（ＣＯ）２ＨｇＣｌ３和铁氯化物（Ｃ４ＨＭｅ４）Ｆｅ（ＣＯ）２Ｃｌ４．１与氯化亚锡反应仅分离到铁氯化物４．以元素分析，ＩＲ和１ＨＮＭＲ谱表征了化合物１～４的结构．     

中国家蚕抗菌肽A基因片段的初步分离

从中国家蚕蛹中提取基因组ＤＮＡ，根据中国家蚕抗菌肽Ａ的ｃＤＮＡ序列设计引物，从基因组ＤＮＡ中扩增天然抗菌肽基因，得到７５０ｂｐ，１１００ｂｐ，１６００ｂｐ左右的３个片段，用内引物扩增法，初步证实中国家蚕抗菌肽Ａ基因至少存在７５０ｂｐ，１１００ｂｐ左右大小的两个拷贝。     

钴原子簇化学研究Ⅵ．含2，4－二硫代乙内酰脲分子片卡宾的三核钴羰基硫簇合物的合成

用Ｃｏ＿２（ＣＯ）＿８与２，４－二硫代乙内酰脲Ｓ＝ＣＮＨＣ（Ｒ＿１）（Ｒ＿２）Ｃ（Ｓ）ＮＨ反应，得到两类６个新的可能具有手征性的三核钴羰基硫簇合物ＣＯ＿３（ＣＯ）＿７（μ＿３－Ｓ）［μ，η￣２－，对它们进行了元素分析、ＩＲ和￣１ＨＮＭＲ谱表征，证明它们的分子骨架为四面体构型，前期配体２，４－二硫代乙内酰脲在反应过程中至少破碎成四种不同分子片，通过Ｃ、Ｎ、Ｓ原子与簇骨架Ｃｏ原子键合。     

一个家蚕基因组MAR的克隆及其初步分析

家蚕（Ｂｏｍｂｙｘｍｏｒｉ）基因组大片段ＤＮＡ经ＢａｍＨＩ完全酶解后,克隆到质粒ｐＵＣ１８中而构建成一个家蚕基因组文库．通过与家蚕细胞核基质的体外结合,从该文库中筛选到一个包含ＭＡＲ的克隆ｐＣ１１ｅ,其中外源插入片段Ｃ１１ｅ长约２．３ｋｂ．Ｃ１１ｅ的限制性酶谱分析及其酶切片段的体外结合实验表明,ＭＡＲ位于Ｃ１１ｅ上的ＳｐｈＩ和ＨｉｎｃⅡ位点之间,长１．０ｋｂ．由于这是家蚕中发现的第一个ＭＡＲ,因此我们称之为ＢｍＭＡＲ１．进一步借助ＤＮａｓｅＩ敏感性分析和ＳｏｕｔｈｅｒｎＢｌｏｔ,对ＢｍＭＡＲ１在家蚕细胞内与核基质结合的情况以及它与人β干扰素（ｈｕＩＦＮ－β）基因５′上游ＭＡＲ之间的同源性进行了研究．     

家蚕抗菌肽CM4组分杀菌机理的激光共聚焦显微镜观察

报道了家蚕抗菌肽对大肠杆菌、金黄色葡萄球菌和绿脓杆菌的杀菌作用,用抗菌肽处理大肠杆菌和金黄色葡萄球菌,与对照组相比,它们的OD值随时间明显下降,平板培养克隆数减少,以荧光素FTIC标记抗菌肽作用于大肠杆菌、金黄色葡萄球菌和绿脓杆菌等细菌,用激光共聚焦扫描显微镜观察,发现抗菌肽迅速包围菌体,密集于细胞膜,损伤膜的完整性,出现大小不等的孔洞,菌体断裂,最后死亡,说明细菌结构是抗菌肽CM4攻击的首要靶位点。     

抗家蚕抗菌肽单克隆抗体杂交瘤细胞系的建立

首次报道了抗家蚕抗菌肽（一种小分子多肽）单克隆抗体杂交瘤细胞系的建立．用ＦＰＬＣ纯化家蚕抗菌肽（ＡＢＰ）获得了电泳一条带的均一样品；将它与辣根过氧化物酶（ＨＲＰ）偶联，以此偶联物免疫ＢＡＬＢ／Ｃ鼠．以抗菌肽—牛血清白蛋白（ＡＢＰ－ＢＳＡ）做包被物ＥＬＩＳＡ筛选出５个阳性杂交瘤细胞株，冻存复苏后得到三个稳定分泌抗体的阳性细胞株，抗体ＩｇＧ亚型为ＩｇＧ２ａ．统计了杂交瘤的染色体数     

家蚕抗菌肽CM4组分杀菌机理的激光共聚焦显微镜观察

报道了家蚕抗菌肽对大肠杆菌、金黄色葡萄球菌和绿脓杆菌的杀菌作用.用抗菌肽处理大肠杆菌和金黄色葡萄球菌,与对照组相比,它们的OD值随时间明显下降,平板培养克隆数减少.以荧光素FITC标记抗菌肽作用于大肠杆菌、金黄色葡萄球菌和绿脓杆菌等细菌,用激光共聚焦扫描显微镜观察,发现抗菌肽迅速包围菌体,密集于细胞膜,损伤膜的完整性,出现大小不等的孔洞,菌体断裂,最后死亡.说明细菌膜结构是抗菌肽CM4攻击的首要靶位点.     

视黄酸对胃癌细胞NM—IF系统变化的影响

选择性抽提整装扫描与透射电镜观察显示,人胃腺癌ＭＧｃ８０－３细胞核骨架纤维和中间纤维数量较少、分布不均匀,核纤层为厚薄不一结构,与两类纤维联系不密切．经１０－６ｍｏｌ／ＬＲＡ处理后,细胞核骨架纤维和中间纤维数量增多、结构层次丰富,分布均匀并相互交织成规则网络,两类纤维通过薄层均一的核纤层发生密切联系,形成贯穿整个细胞核质区域的完整体系．表明经ＲＡ诱导处理后ＭＧｃ８０－３细胞的核骨架－中间纤维系统产生了与正常细胞相似的恢复性改变．这种变化是癌细胞恶性表型逆转的重要形态特征和功能表现．     

包囊游仆虫细胞的类中间纤维细胞骨架体系

应用生化分级抽提,并结合DGD包埋 去包埋透射电镜样品制备方法显示,包囊游仆虫营养细胞和休眠细胞中,均存在由直径10 nm左右的单根纤维及单根纤维聚集成的纤维束为结构单元形成的类中间纤维细胞骨架体系.其中,营养细胞的类中间纤维构成的细胞质三维网架,在细胞膜内缘以较密集的纤维网占有了整个表质层,在表质层内缘的细胞质深部纤维形成较松散的网络,网内常见附着有细胞器及一些电子密度颗粒;核纤层位于大核核膜内缘,纤维紧密聚集成网;核骨架纤维网分布比较致密,未见有电子密度颗粒附着.休眠细胞中含有与营养细胞相似的纤维网架结构,但位于细胞内不同层次的纤维网比营养细胞中的同种结构要致密得多,这可能与纤毛虫形成包囊时细胞大范围的收缩有关.并且值得注意的是,在休眠细胞包囊壁的内层壁中也观察到相似于中间纤维的纤维网络,其纤维网均匀和致密地分布在整个包囊壁层中.电泳图谱显示,纤毛虫形成包囊后,保留了营养细胞中的部分蛋白条带,失去了部分条带,新产生了一些特异的条带.结果表明,包囊游仆虫的类中间纤维 核骨架体系,是细胞在营养条件下和休眠状态下都稳定存在的结构,它可能起到比微管类骨架更重要的作用.并且休眠细胞中该体系产生的一些特异蛋白条带,可能是纤毛虫休眠生命活动中的重要蛋白.     

人肝癌细胞骨架网络系统的初步研究

利用ＴｒｉｔｏｎＸ－１００及其联合（ＮＨ４）２ＳＯ４的抽提技术与ＣｏｏｍａｓｉｅｂｌｕｅＲ２５０染色、免疫酶标技术相结合，体外实验比较研究人肝癌细胞系（ＨｅｐＧ２）细胞骨架网络的分布构像及其中间纤维蛋白构型。结果：人肝癌细胞系（ＨｅｐＧ２）显示其细胞骨架网络的分布构像及其中间纤维对Ｖｉｍｅｎｔｉｎ、Ｋｅｒａｔｉｎ两种抗体均呈现阳性反应。结论：恶性肿瘤细胞的中间纤维蛋白构型可能具有异质性的蛋白分子共表达，这对仅以ＴｒｉｔｏｎＸ－１００加（ＮＨ４）２ＳＯ４的抽提技术进行恶性肿瘤细胞中间纤维蛋白构型分析，是一个必需考虑的问题。     

Site-specific phosphorylation induces disassembly of vimentin filaments in vitro

Intermediate filaments are a major component of the cytoskeleton of eukaryotic cells. Although there appear to be at least five distinct classes of these filaments, cells of mesenchymal origin and most cells in culture contain the intermediate filament composed of the subunit protein vimentin. Vimentin exists in a nonphosphorylated as well as in a phosphorylated form, and there is increased phosphorylation of this protein when the filament undergoes marked redistribution in various cells. The role of phosphorylation on assembly-disassembly and organization of the vimentin filament has remained obscure. We report here a stable and purified system allowing biochemical examination of vimentin filament assembly and disassembly. Using this in vitro system, we carried out stoichiometrical phosphorylations, using purified protein kinases. We obtained evidence for site-specific, phosphorylation-dependent disassembly of the vimentin filament.     

Redistribution of intermediate filaments during capping of lymphocyte surface molecules

Intermediate filaments (IF) constitute a major cytoplasmic filamentous network of higher eukaryotic cells that is distinct from actin and myosin microfilaments or microtubules. Although structurally similar, these filaments are formed by chemically and antigenically different proteins. Vimentin is the major IF polypeptide of mesenchymal cells and cultured non-mesenchymal cell lines. Recently, we have characterized a monoclonal IgM antibody from a patient with Waldenstr?m's macroglobulinaemia which is directed against vimentin. Using this monoclonal antibody, we have shown by direct immunofluorescence that intermediate filaments of human B and T lymphocytes consist of vimentin. In cells exposed to colcemid, the intermediate filaments retracted into a juxtanuclear aggregate ('coli') characteristic of vimentin filaments. As most components of the cytoskeleton, especially actin and myosin, have been implicated in the capping phenomenon, we investigated the effect of capping of either beta 2-microglobulin or membrane immunoglobulins on the organization of the intermediate filament network. We report that capping of these surface molecules induced the redistribution of vimentin just beneath the cap. When colcemid-treated cells were allowed to cap, the location of the cap always coincided with the coil, suggesting that the anchorage point of intermediate filaments is situated within the uropod.     

The nuclear lamina is a meshwork of intermediate-type filaments

The nuclear lamina, a protein meshwork lining the nucleoplasmic surface of the inner nuclear membrane, is thought to provide a framework for organizing nuclear envelope structure and an anchoring site at the nuclear periphery for interphase chromatin. In several higher eukaryotic cells, the lamina appears to be a polymer comprised mainly of one to three immunologically related polypeptides of relative molecular mass (Mr) 60,000-75,000 (60-70K) termed lamins. Three lamins (A, B, and C) are typically present in mammalian somatic cells. Previous studies on nuclear envelopes of rat liver and Xenopus oocytes suggested that the lamina has a fibrillar or filamentous substructure. Interestingly, protein sequences recently deduced for human lamins A and C from complementary DNA clones indicate that both of these polypeptides contain a region of approximately 350 amino acids very similar in sequence to the coiled-coil alpha-helical rod domain that characterizes all intermediate-type filament (IF) proteins. Here we analyse the supramolecular organization of the native nuclear lamina and the structure and assembly properties of purified lamins, and show that the lamins constitute a previously unrecognized class of IF polypeptides.     

中频宽带信号采集存储回放系统设计

目前中频宽带信号在通讯及雷达领域中的应用十分广泛,为了将无法实时处理的信号后续再处理以及将采集到的信号在其他地点重现,设计了一种中频宽带信号采集存储回放系统.基于FPGA(field-programmable gate array)+ADC(ana-log-to-digital converter)/DAC(digit...     

A keratin cytoskeletal protein regulates protein synthesis and epithelial cell growth

Cell growth, an increase in mass and size, is a highly regulated cellular event. The Akt/mTOR (mammalian target of rapamycin) signalling pathway has a central role in the control of protein synthesis and thus the growth of cells, tissues and organisms. A striking example of a physiological context requiring rapid cell growth is tissue repair in response to injury. Here we show that keratin 17, an intermediate filament protein rapidly induced in wounded stratified epithelia, regulates cell growth through binding to the adaptor protein 14-3-3sigma. Mouse skin keratinocytes lacking keratin 17 (ref. 4) show depressed protein translation and are of smaller size, correlating with decreased Akt/mTOR signalling activity. Other signalling kinases have normal activity, pointing to the specificity of this defect. Two amino acid residues located in the amino-terminal head domain of keratin 17 are required for the serum-dependent relocalization of 14-3-3sigma from the nucleus to the cytoplasm, and for the concomitant stimulation of mTOR activity and cell growth. These findings reveal a new and unexpected role for the intermediate filament cytoskeleton in influencing cell growth and size by regulating protein synthesis.     

Formins： Bringing new insights to the organization of actin cytoskeleton

The actin cytoskeleton is an important component of eukaryotic cell cytoskeleton and is temporally and spatially controlled by a series of actin binding proteins (ABPs). Among ABPs, formin family proteins have attracted much attention as they can nucleate unbranched actin filament from the profilin bound actin pool in vivo. In recent years, a number of formin family members from different organisms have been reported, and their characteristics are known more clearly, although some questions are still to be clarified. Here, we summarize the structures, func-tions and nucleation mechanisms of different formin family proteins, intending to compare them and give some new clues to the study of formins.