山东省淡水真菌三个中国新记录种

2010年6–10月期间,我们对山东省的淡水真菌进行调查和采集,发现3个中国新记录种:长鞭状透明长棒孢Hyalocamposporium longiflagellatum、乌拉圭斯宾塞马丁氏孢菌Spencermartinsia uruguayensis和大洋格腔孢菌Pleospora pelagica。主要对这3种淡水真菌进行形态描述及讨论。     

WEE1 激酶及其抑制剂在抗肿瘤治疗中的应用进展

WEE1激酶是一种细胞周期调节蛋白,能调控细胞周期蛋白依赖性激酶1(cyclin-dependent kinase 1,CDK1)的磷酸化状态,从而调节CDK1与细胞周期蛋白B(cyclin B)复合物的活性从而实现对细胞周期的调控,且对DNA损伤检查点具有重要的调节作用。WEE1是G2/M期阻滞的关键基因,起着重要的监测作用,在一些癌症中过表达,抑制或下调WEE1激酶均能引发有丝分裂灾难,因此WEE1激酶抑制剂可能在抗癌治疗中有关键作用。在癌症的治疗过程中,WEE1抑制剂与DNA损伤剂、化学药物等联合使用会得到比单独使用更为有效,且在p53缺失的癌细胞中能发挥更好的效果。目前WEE1已成为许多癌症治疗的关键靶点之一,其抑制剂MK-1775已处于临床研究阶段,且能增强一些DNA损伤剂对p53缺失的癌细胞的杀伤能力。本文就WEE1激酶及其抑制剂在抗癌治疗中的应用作一综述。     

Visualization and Characterization of High-Order Chromatin Fibers under Light Microscope during Interphase and Mitotic Stages in Plants

Using genomic in situ hybridization with genomic DNA, high-order chromatin fibers were successfully exhibited under a light microscope through the cell cycle in barley, rice, maize and field bean. From the interphase to prophase and metaphase of mitosis, the fibers were basically similar. Each was estimated to be around 200 nm in diameter, but the strength of signals was not the same along the fiber length. Through the cell cycle a series of dynamic distribution changes occurred in the fibers. In the interphase, they were unraveled. At the early prophase they were arranged with parallel and mirror symmetry. During late-prophase and metaphase, the fibers were bundled and became different visible chromosomes. The parallel coiling and mirror symmetry structures were visible clearly until the metaphase. In anaphase they disappeared. During telophase, in peripheral regions of congregated chromosome group, borderlines of the chromosomes disappeared and the fibers were unraveled. This demonstrated that mitotic chromosomes are assembled and organized by parallel and adjacent coiling of the fibers and the fibers should be the highest order structure for DNA coiling.     

Function and regulation of Aurora／Ipllp kinase family in cell division

During mitosis,the parent cell distributes its genetic materials equally into two daughter cells through chromosome segregation,a complex movements orchestrated by mitotic kinases and its effector proteins.Faithful chromosome segregation and cytokinesis ensure that each daughter cell receives a full copy of genetic materials of parent cell.Defects in these processes can lead to aneuploidy or polyploidy.Aurora/Ipllp family, a class of conserved serine/threonine kinases,plays key roles in chromosome segregation and cytokinesis.This article highlights the function and regulation of Aurora/Ipllp family in mitosis and provides potential links between aberrant regulation of Aurora/Ipllp kinases and pathogenesis of human cancer.     

稻瘿蚊灾变原因及综合治理技术

80年代中后期以来,我省稻瘿蚊年度成灾频率高,发生危害重。造成大发生主要原因是耕作制度改变、气候条件适台、咀及栽培管理、天敌因素影响等。近几年通过组织实施以农业生态防治为基础,加上科学用药等综合治理措施,取得了良好防治效果。     

多头绒泡菌有丝分裂后细胞核重建过程的形态学研究

以进行自然同步核内有丝分裂的多头绒孢菌（Ｐｈｙｓａｒｕｍｐｏｌｙｃｅｐｈａｌｍ）原生质团为材料,应用常规制片和整体银染后制片的电镜技术研究了有丝分裂后细胞核的形态构建过程,形成新核仁的前体物质在有丝分裂中期时莠在染色体区域的周围,末期时与染色体组一起到达两极,子细胞核刚形成时核仁物质与染色质混合,以后核仁物质相互汇合并同染色质逐渐分开,最后形成一个大核仁,染色质在有丝分裂后期开始解集缩,到两极后在     

基于变易理论的“有丝分裂”教学设计

变易理论是基于学生的思维特点,能直接指导教学实践的教育理论。此教学设计以变易理论为主要理论指导,借助情境模拟突破"有丝分裂"这一教学难点。     

Cytokinesis and cancer： Polo loves ROCK＇n＇ Rho（A）

Cytokinesis is the last step of the M (mitosis) phase, yet it is crucial for the faithful division of one cell into two. Cytokinesis failure is often associated with cancer. Cytokinesis can be morphologically divided into four steps: cleavage furrow initiation, cleavage furrow ingression, midbody formation and abscission. Molecular studies have revealed that RhoA as well as its regulators and effectors are important players to ensure a successful cytokinesis. At the same time, Polo-like kinase 1 (Plk1) is an important kinase that can target many substrates and carry out different functions during mitosis, including cytokinesis. Recent studies are beginning to unveil a closer tie between Plk1 and RhoA networks. More specifically, Plk1 phosphorylates the centralspindlin complex Cyk4 and MKLP1/CHO1, thus recruiting RhoA guanine nucleotide-exchange factor (GEF) Ect2 through its phosphopeptide-binding BRCT domains. Ect2 itself can be phosphorylated by Plk1 in vitro. Plk1 can also phosphorylate another GEF MyoGEF to regulate RhoA activity. Once activated, RhoA-GTP will activate downstream effectors, including ROCK1 and ROCK2. ROCK2 is among the proteins that associate with Plk1 Polo-binding domain (PBD) in a large proteomic screen, and Plk1 can phosphorylate ROCK2 in vitro. We review current understandings of the interplay between Plk1, RhoA proteins and other proteins (e.g., NudC, MKLP2, PRC1, CEP55) involved in cytokinesis, with particular emphasis of its clinical implications in cancer.     

褐藻寡糖抗环磷酰胺诱导蚕豆根尖的细胞遗传毒性

采用蚕豆根尖细胞的微核试验和染色体畸变试验方法,测定不同浓度的褐藻寡糖对环磷酰胺(cyclophosphamide,CP)诱导的蚕豆根尖细胞的微核率、有丝分裂指数和染色体畸变率的影响。结果表明:褐藻寡糖能有效抑制环磷酰胺诱导的蚕豆根尖细胞微核的产生,即在一定浓度范围内,微核率随褐藻寡糖处理浓度的降低而减少,但低于一定浓度后反而呈上升趋势;不同浓度的褐藻寡糖均可使蚕豆根尖细胞有丝分裂指数增大;褐藻寡糖还能有效降低蚕豆根尖细胞染色体畸变率。因此,褐藻寡糖对蚕豆根尖细胞具有明显的诱抗活性和调节细胞分裂生长的效应。     

Mitotic phosphorylation of PRC1 at Thr470 is required for PRC1 oligomerization and proper central spindle organization

During cell division, chromosome segregation is orchestrated by the interaction of spindle microtubules with thecentromere. A dramatic remodeling of interpolar microtubules into an organized central spindle between the separatingchromatids is required for the initiation and execution of cytokinesis. Central spindle organization requires mitotic kine-sins, the chromosomal passenger protein complex, and microtubule bundling protein PRC1. PRC1 is phosphorylated byCdc2 at Thr470 and Thr481 during mitosis. However, the functional relevance of PRC1 phosphorylation at Thr470 hasremained elusive. Here we show that expression of the non-phosphorylatable mutant PRC1~(T470A) but not the phospho-mimi-cking mutant PRC1~(T470E) causes aberrant organization of the central spindle. Immunoprecipitation experiment indicatesthat both PRC1~(T470A) and PRC1~(T470E) mutant proteins associate with wild-type PRC1, suggesting that phosphorylationof Thr470 does not alter PRC1 self-association. In addition, in vitro co-sedimentation experiment showed that PRC1binds to microtubule independent of the phosphorylation state of Thr470. Gel-filtration experiment suggested that phos-phorylation of Thr470 promotes oligomerization of PRC1. Given the fact that prevention of the Thr470 phosphorylationinhibits PRC1 oligomerization in vitro and causes an aberrant organization of central spindle in vivo, we propose thatthis phosphorylation-dependent PRC1 oligomerization ensures that central spindle assembly occurs at the appropriatetime in the cell cycle.