Cytokinesis

细胞分裂
  • 文章类型: Journal Article
    一些人体研究表明,手机特定的电磁场可能会导致人类癌症,但目前尚不清楚潜在的分子机制。有关染色体损伤(与癌症诱发有因果关系)的研究是有争议的,并且基于使用问卷调查来评估暴露。我们实现了第一个人类干预试验,其中在受控条件下研究了染色体损伤和急性毒性作用。参与者通过头部随机分配的一侧的耳机连续5天暴露于低剂量和高剂量的UMTS信号(n=20,0.1W/kg和n=21至1.6W/kg的比吸收率)2小时。在暴露前和暴露后三周,从脸颊和微核收集颊细胞(MN,它们是由于结构和数字染色体畸变而形成的)和其他反映有丝分裂紊乱和急性细胞毒性作用的核异常进行评分。我们没有发现由基因扩增引起的MN和核芽诱导的证据,但是由于细胞分裂受到干扰而形成的双核细胞显着增加,和核分裂细胞,这表明细胞死亡。在暴露较少的一侧的细胞中没有看到这样的效果。我们的发现表明,在本实验条件下,手机特定的高频电磁场不会引起口腔粘膜细胞的急性染色体损伤。然而,我们发现了细胞周期紊乱和细胞毒性的明确证据。这些效应可能在诱导人类不利的长期健康效应中起因果作用。
    Several human studies indicate that mobile phone specific electromagnetic fields may cause cancer in humans but the underlying molecular mechanisms are currently not known. Studies concerning chromosomal damage (which is causally related to cancer induction) are controversial and those addressing this issue in mobile phone users are based on the use of questionnaires to assess the exposure. We realized the first human intervention trial in which chromosomal damage and acute toxic effects were studied under controlled conditions. The participants were exposed via headsets at one randomly assigned side of the head to low and high doses of a UMTS signal (n = 20, to 0.1 W/kg and n = 21 to 1.6 W/kg Specific Absorption Rate) for 2 h on 5 consecutive days. Before and three weeks after the exposure, buccal cells were collected from both cheeks and micronuclei (MN, which are formed as a consequence of structural and numerical chromosomal aberrations) and other nuclear anomalies reflecting mitotic disturbance and acute cytotoxic effects were scored. We found no evidence for induction of MN and of nuclear buds which are caused by gene amplifications, but a significant increase of binucleated cells which are formed as a consequence of disturbed cell divisions, and of karyolitic cells, which are indicative for cell death. No such effects were seen in cells from the less exposed side. Our findings indicate that mobile phone specific high frequency electromagnetic fields do not cause acute chromosomal damage in oral mucosa cells under the present experimental conditions. However, we found clear evidence for disturbance of the cell cycle and cytotoxicity. These effects may play a causal role in the induction of adverse long term health effects in humans.
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  • 文章类型: Journal Article
    动物和真菌细胞的细胞分裂主要取决于Anillin支架蛋白。裂变酵母Anillin相关的Mid1将细胞动力学环前体节点锚定到膜上。然而,尚不清楚其Pleckstrin同源性(PH)和C2C末端结构域是否都作为单体或二聚体与膜结合,如果一个领域起主导作用。我们研究了具有酵母样脂质组成的膜附近的Mid1膜与全原子分子动力学的结合。在全C末端区域开始远离膜的模拟中,Mid1以垂直方向通过C2的无序L3环结合,PH远离膜。然而,具有最初与膜结合的C2和PH两者的构型保持与膜相关联。C2-PH二聚体的模拟显示广泛的不对称膜接触。这些多种结合模式可能反映了Mid1与膜的多种相互作用,节点蛋白,以及承受机械力的能力.
    Cytokinesis of animal and fungi cells depends crucially on the anillin scaffold proteins. Fission yeast anillin-related Mid1 anchors cytokinetic ring precursor nodes to the membrane. However, it is unclear if both of its Pleckstrin Homology (PH) and C2 C-terminal domains bind to the membrane as monomers or dimers, and if one domain plays a dominant role. We studied Mid1 membrane binding with all-atom molecular dynamics near a membrane with yeast-like lipid composition. In simulations with the full C terminal region started away from the membrane, Mid1 binds through the disordered L3 loop of C2 in a vertical orientation, with the PH away from the membrane. However, a configuration with both C2 and PH initially bound to the membrane remains associated with the membrane. Simulations of C2-PH dimers show extensive asymmetric membrane contacts. These multiple modes of binding may reflect Mid1\'s multiple interactions with membranes, node proteins, and ability to sustain mechanical forces.
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  • 文章类型: Journal Article
    大多数细胞可以感知并改变其形状以执行基本的细胞过程。在许多真核生物中,septin细胞骨架是协调形状变化如胞质分裂的一个组成部分,极化生长,和移民。Septins是细丝形成蛋白,组装形成不同的高级结构,在许多情况下,在质膜的不同区域发现,最值得注意的是在微米尺度的正曲率区域。细胞中光学显微镜的局限性阻碍了体内隔膜组装过程的监测,以及与细胞膜和细胞骨架元素相互作用的复杂性,使得难以量化生命系统中的隔膜动力学。幸运的是,在过去的十年中,在无细胞系统中重建septin细胞骨架以在高时空分辨率下剖析控制septin组装的机制方面取得了实质性进展。septin组装的核心步骤包括septin杂低聚物与膜的缔合和解离,聚合成长丝,以及通过细丝之间的相互作用形成高阶结构。这里,我们提出了三种在不同情况下观察隔膜组装的方法:平面双层,球形支撑,和杆支撑。这些方法可用于在组装的不同阶段确定隔膜的生物物理参数:作为结合膜的单个八聚体,作为细丝,作为细丝的集合。我们使用这些参数与曲率采样和优先吸附的测量值配对,以了解曲率感测如何在各种长度和时间尺度上运行。
    Most cells can sense and change their shape to carry out fundamental cell processes. In many eukaryotes, the septin cytoskeleton is an integral component in coordinating shape changes like cytokinesis, polarized growth, and migration. Septins are filament-forming proteins that assemble to form diverse higher-order structures and, in many cases, are found in different areas of the plasma membrane, most notably in regions of micron-scale positive curvature. Monitoring the process of septin assembly in vivo is hindered by the limitations of light microscopy in cells, as well as the complexity of interactions with both membranes and cytoskeletal elements, making it difficult to quantify septin dynamics in living systems. Fortunately, there has been substantial progress in the past decade in reconstituting the septin cytoskeleton in a cell-free system to dissect the mechanisms controlling septin assembly at high spatial and temporal resolutions. The core steps of septin assembly include septin heterooligomer association and dissociation with the membrane, polymerization into filaments, and the formation of higher-order structures through interactions between filaments. Here, we present three methods to observe septin assembly in different contexts: planar bilayers, spherical supports, and rod supports. These methods can be used to determine the biophysical parameters of septins at different stages of assembly: as single octamers binding the membrane, as filaments, and as assemblies of filaments. We use these parameters paired with measurements of curvature sampling and preferential adsorption to understand how curvature sensing operates at a variety of length and time scales.
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  • 文章类型: Journal Article
    安泽蜂蜜在土耳其是众所周知的,用于其药用特性,尤其是咽炎,扁桃体炎,溃疡和癌症。在这项研究中,我们调查了安泽蜂蜜,它被证明具有抗氧化剂,抗肿瘤,和抗炎特性,通过细胞遗传学方法对X射线诱导的基因毒性损伤具有保护作用。从20名健康志愿者中分离的外周血淋巴细胞分为两组,并通过常规方法进行培养。研究组淋巴细胞用10%稀释的蜂蜜处理,而对照组则不用。在培养的第48小时,两组均暴露于高剂量(2Gy)X射线。常规细胞遗传学染色和Giemsa显带方法用于评估染色体断裂和环形成。通过胞质分裂阻断微核(CBMN)测定确定微核频率。组间比较采用配对样本t检验。安泽蜂蜜,这是用黄体孢粉分析的,被使用。研究组的微核频率显着降低(CI=348.75±31,中位数326,分钟。98,最大。704)与对照组相比(CI=489.10±27,中位数500,min。最大216号.645)(p=.001)。研究组染色体断裂也显着减少(CI=118.70±16,中位数109,分钟。12,最大。316)与对照组相比(CI=233.60±25,中位数225,分钟。最大65岁.492)(p<0.0001)。这是第一项研究表明,可以通过在体外添加Anzer蜂蜜来预防或减轻由X射线辐射引起的健康志愿者外周血淋巴细胞的遗传毒性损伤。这些结果鼓励了有关蜂蜜保护作用的进一步研究。研究重点:安泽蜂蜜对辐射诱导的遗传毒性具有基因保护作用,可能是通过防止氧化损伤。
    Anzer honey is well known in Turkey and used for its medicinal properties, especially for pharyngitis, tonsillitis, ulcers and cancer. In this study, we investigated whether Anzer honey, which is shown to have antioxidant, anti-tumoral, and anti-inflammatory properties, has a protective effect against X-ray induced genotoxic damage by cytogenetic methods. Peripheral blood lymphocytes isolated from 20 healthy volunteers were divided into two groups and cultivated by conventional methods. Study group lymphocytes were treated with 10% diluted honey while those in the control group were not. Both groups were exposed to a high dose (2 Gy) X-ray at the 48th hour of culture. Conventional cytogenetic staining and Giemsa banding methods were applied to evaluate chromosomal breakage and ring formation. Micronucleus frequencies were determined by the cytokinesis-block micronucleus (CBMN) assay. Paired sample t test was used to compare groups. Anzer honey, which was analyzed melissopalynologically, was used. Micronucleus frequency was significantly decreased in the study group (CI = 348.75 ± 31, median 326, min. 98, max. 704) compared to the control group (CI = 489.10 ± 27, median 500, min. 216, max. 645) (p = .001). Chromosomal breakage was also significantly decreased in the study group (CI = 118.70 ± 16, median 109, min. 12, max. 316) compared to the control group (CI = 233.60 ± 25, median 225, min. 65, max. 492) (p < .0001). This is the first study indicating that genotoxic damage in the peripheral blood lymphocytes of healthy volunteers induced by X-radiation may be prevented or alleviated by adding Anzer honey in vitro. These results encourage further research about the protective effects of honey. RESEARCH HIGHLIGHTS: Anzer honey has a genoprotective effect against radiation-induced genotoxicity, probably by preventing oxidation damage.
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  • DOI:
    文章类型: Journal Article
    分析不同麻醉方法对食管癌手术患者围手术期细胞免疫及远期预后的影响。
    方法:选取2016年1月至2017年1月郑州大学人民医院收治的120例食管癌患者,随机分为全麻n=40),PG组(全身麻醉椎旁神经阻滞,n=40)和EG组(全身麻醉的硬膜外麻醉,n=40)。
    方法:采用焦虑自评量表和视觉模拟评分法比较3组患者术后焦虑和疼痛程度。此外,比较三组患者的不良反应。白细胞介素-6(IL-6)的水平,IL-4,肿瘤坏死因子-α(TNF-α),干扰素-γ(IFN-γ),和T细胞亚群的存活(CD3+,CD4+,CD8+,CD4+/CD8+)术前,在操作结束时,并在术后第1天(POD)1和POD2通过ELISA或流式细胞术进行测量。
    结果:在PG和EG组中,VAS评分较低,与GA组相比,使用的阿片类药物和血管活性药物较少。在EG和PG组中,较高的CD3+和CD4+细胞存活率和较低水平的Cor,与GA组相比,在手术结束时或手术结束时鉴定出IL-4和IL-6。此外,PG组和EG组的术后生存曲线优于GA组。
    结论:椎旁神经阻滞或硬膜外麻醉和全身麻醉的联合应用可改善食管癌手术患者的围手术期免疫功能和长期预后。
    To analyze the effects of different anaesthetic methods on perioperative cellular immunity and long-term outcome in patients who undergo esophageal cancer surgery.
    METHODS: A total of 120 patients with esophageal cancer admitted to Zhengzhou University People\'s Hospital from January 2016 to January 2017 were recruited and randomly divided into a GA group (general anaesthesia, n = 40), a PG group (paravertebral nerve block with general anaesthesia, n = 40) and an EG group (epidural anaesthesia with general anaesthesia, n = 40).
    METHODS: Self-rating anxiety scale and visual analogue scale scores were adopted to compare postoperative anxiety and the degree of pain of patients in the three groups. In addition, the adverse reactions of patients in the three groups were compared. The levels of interleukin-6 (IL-6), IL-4, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and the survival of T-cell subsets (CD3+, CD4+, CD8+, CD4+/CD8+) before operation, at the end of operation, and on postoperative day (POD) 1 and POD 2 were measured by either ELISA or flow cytometry.
    RESULTS: In the PG and EG group, the VAS scores were lower, and fewer opioids and vasoactive agents were used than in the GA group. In both the EG and PG groups, higher CD3+ and CD4+ cell survival and lower levels of Cor, IL-4, and IL-6 were identified at the end of or after the surgery than in the GA group. Moreover, the postoperative survival curves of the PG and EG groups were better than that of the GA group.
    CONCLUSIONS: The combination of paravertebral nerve block or epidural anaesthesia and general anaesthesia may improve perioperative immune function and long-term outcome in patients who undergo esophageal cancer surgery.
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  • 文章类型: Review
    在有丝分裂结束时需要细胞分裂来切割子细胞,并且依赖于RhoAGTP酶的时空控制。细胞分裂失败可导致细胞命运或非整倍性的变化,这在发育过程中可能是有害的和/或可能导致癌症。然而,我们对胞质分裂过程中调节RhoA的途径的了解是有限的,其他Rho家族GTPases的作用尚不清楚。这在很大程度上是因为RhoGTPases的研究提出了使用传统细胞生物学和生物化学方法的独特挑战,它们具有多效性功能,使得遗传研究难以解释。控制和检测活性Rho的新一代光遗传学工具和生物传感器已经克服了这些挑战中的一些,并有助于阐明RhoA在胞质分裂中的作用。然而,需要改进来揭示其他RhoGTP酶在胞质分裂中的作用,并确定控制Rho活性的分子机制。这篇综述探讨了胞质分裂中的一些悬而未决的问题,并探索了RhoGTPases成像和控制的工具。
    Cytokinesis is required to cleave the daughter cells at the end of mitosis and relies on the spatiotemporal control of RhoA GTPase. Cytokinesis failure can lead to changes in cell fate or aneuploidy, which can be detrimental during development and/or can lead to cancer. However, our knowledge of the pathways that regulate RhoA during cytokinesis is limited, and the role of other Rho family GTPases is not clear. This is largely because the study of Rho GTPases presents unique challenges using traditional cell biological and biochemical methods, and they have pleiotropic functions making genetic studies difficult to interpret. The recent generation of optogenetic tools and biosensors that control and detect active Rho has overcome some of these challenges and is helping to elucidate the role of RhoA in cytokinesis. However, improvements are needed to reveal the role of other Rho GTPases in cytokinesis, and to identify the molecular mechanisms that control Rho activity. This review examines some of the outstanding questions in cytokinesis, and explores tools for the imaging and control of Rho GTPases.
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  • 文章类型: Journal Article
    表观遗传调控的干扰是癌症的公认机制,但其对铅(Pb)相关毒性的作用尚未得到充分研究。我们旨在研究职业性铅暴露是否与微核(MN)频率相关,并进一步探讨表观遗传基因调控的中介作用。所有从中国酸蓄电池厂招募的铅暴露工人,检测血铅水平(BLL)和淋巴细胞MN频率.此外,七个基因的甲基化水平(Line-1,RASSF1A,在230名工人中检查了RUNX3,p16,CYP26C1,hMLH1,p15)。使用鲁棒泊松回归模型来研究BLL与MN频率之间的关联。中介分析用于探索特定DNA甲基化的中介作用。在总共677名参与者中,71%是男性,BLL中位数为229.1μg/L(P25=155.5,P75=319.3;范围为8.9至647.7μg/L),平均MN频率为2.5‰(SD=1.8‰;范围为0至9‰)。来自基础模型的结果,根据年龄调整,性别,和身体质量指数,结果表明,在BLL中,每增加100μg/L,MN频率将增加1.38(95%保密间隔:1.34,1.43)。使用分类的暴露变量分析,观察到MN频率的BLL剂量反应增加:2.74(2.13,3.51),3.43(2.73,4.32),4.41(3.89,5.01)至6.86(6.02,7.81)。中介分析表明,Line-1甲基化显着介导了BLL与MN频率相关的3.6%。职业性铅暴露以剂量-反应关系诱导MN频率。这种关联的一部分是由Line-1启动子甲基化介导的。
    Perturbation of epigenetic regulation is a well-established mechanism for cancer but its role for lead (Pb)-associated toxicity has not been adequately investigated. We aimed to investigate whether occupational Pb exposure is associated with micronuclei (MN) frequency and to further explored the mediating roles of epigenetic gene regulation. All the Pb-exposed workers recruited from a Chinese acid battery factory, blood lead levels (BLLs) and MN frequency in lymphocytes were measured. In addition, methylation levels of seven genes (Line-1, RASSF1A, RUNX3, p16, CYP26C1, hMLH1, p15) were examined among 230 workers. Robust Poisson regression model was used to investigate the association between BLLs and MN frequency. Mediation analysis was used to explore the mediating role of specific DNA methylation. Among total 677 participants, 71% were male, median BLLs was 229.1 μg/L (P25  = 155.5, P75  = 319.3; ranged from 8.9 to 647.7 μg/L), mean MN frequency was 2.5‰ (SD = 1.8‰; ranged from 0 to 9‰). Results from base model, adjusted for age, sex, and body mass index, showed that MN frequency would increase 1.38 (95%confidential interval: 1.34, 1.43) per 100 μg/L increment in BLLs. Using categorized exposure variable analyses, a BLLs dose-response increase in MN frequency was observed: 2.74 (2.13, 3.51), 3.43 (2.73, 4.32), 4.41 (3.89, 5.01) to 6.86 (6.02, 7.81). Mediation analysis indicated that Line-1 methylation significantly mediated 3.6% of the association of BLLs with MN frequency. Occupational Pb exposure induces MN frequency in a dose-response relationship. Part of this association was mediated by Line-1 promotor methylation.
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  • 文章类型: Journal Article
    Cytokinesis is the process that separates a cell into two daughter cells at the end of mitosis. Most of our knowledge of cytokinesis comes from overexpression studies, which affects our interpretation of protein function. Gene editing can circumvent this issue by introducing functional mutations or fluorescent probes directly into a gene locus. However, despite its potential, gene editing is just starting to be used in the field of cytokinesis. Here, we discuss the benefits of using gene editing tools for the study of cytokinesis and highlight recent studies that successfully used CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) technology to answer critical questions regarding the function of cytokinesis proteins. We also present methodologies for editing essential genes and discuss how CRISPR interference (CRISPRi) and activation (CRISPRa) can enable precise control of gene expression to answer important questions in the field. Finally, we address the need for gene editing to study cytokinesis in more physiologically relevant contexts. Therefore, this Review provides a roadmap for gene editing to be used in the study of cytokinesis and other cellular processes.
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  • 文章类型: Journal Article
    放射性药物是由放射性核素和具有非药效学作用的非放射性化合物组成的特殊药物,副作用发生率低,和可能的致癌风险,因为它对患者的给药是对生物体的辐射剂量。这些年来,诊断放射性药物引起的辐射损伤已经被评估,包括放射性标记的自体细胞,一组放射性药物,其中从患者中提取的血细胞在体外标记并重新给药以进行诊断。关于与放射性标记的血细胞相关的恶性肿瘤风险增加的可能性没有达成共识。因此,为了更准确地评估与使用[Tc]Tc标记的红细胞相关的潜在致癌风险,通过胞质分裂阻断的微核(CBMN)测定法和通过血液样品的体外外照射构建的剂量反应曲线,研究了细胞在标记过程中接受的辐射剂量。我们的工作能够确定在用[Tc]Tc高tech酸盐体外标记红细胞期间添加的活性范围,以避免对细胞的辐射损伤。推荐用于血容量测定和血管造影的活动不会增加恶性肿瘤的风险,而370MBq的活性显示淋巴细胞染色体畸变。建议评估与体外标记相关的辐射损伤,以估计潜在的致癌风险并将其最小化。
    Radiopharmaceuticals are special medicines composed by a radionuclide and a non-radioactive compound characterized by non-pharmacodynamic effects, low prevalence of side effects, and a possible risk of oncogenesis, since its administration to patients supposes a radiation dose to organism. Over these years, radiation damage induced by diagnosis radiopharmaceuticals has been evaluated, including the radiolabeled autologous cells, a group of radiopharmaceuticals where blood cells extracted from patients are labeled in-vitro and readministered for diagnosis. There is not a consensus about the possibility of increasement of risk for malignancies associated with the radiolabeled blood cells, so for a more accurate evaluation of the potential oncogenic risk related to the administration of [Tc]Tc labeled red blood cells, radiation dose received by the cells during the labeling process is studied by means of the cytokinesis-blocked micronucleus (CBMN) assay and a dose-response curve constructed by in-vitro external irradiation of blood samples. Our work enables to establish the range of activity to be added during the in-vitro labeling of red blood cells with [Tc]Tc pertechnetate to avoid radiation damage to cells. Activities recommended for blood volume determination and angiography do not increase the risk of malignancies, whilst activities of 370 MBq show chromosome aberrations in lymphocytes. Evaluation of the radiation damage related to the in-vitro labeling is recommended to estimate the potential oncogenic risk and minimize it.
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  • 文章类型: Journal Article
    Cytokinesis is the process that completes cell division by partitioning the contents of the mother cell between the two daughter cells. It involves the highly regulated assembly and constriction of an actomyosin contractile ring, whose function is to pinch the mother cell in two. Research on the contractile ring has particularly focused on the signaling mechanisms that dictate when and where the ring is formed. In vivo studies of ring constriction are however scarce and its mechanistic understanding is therefore limited. Here we present several experimental approaches for monitoring ring constriction in vivo, using the four-cell C. elegans embryo as model. These approaches allow for the ring to be perturbed only after it forms and include the combination of live imaging with acute drug treatments, temperature-sensitive mutants and rapid temperature shifts, as well as laser microsurgery. In addition, we explain how to combine these with RNAi-mediated depletion of specific components of the cytokinetic machinery.
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