胆囊腺癌和腺瘤细胞核形态学计量和PCNA定量分析

研究胆囊腺瘤和腺瘤恶变与胆囊腺癌的关系。方法：用ＴＪＴＹ－３００全自动图像分析仪测定了２５例胆囊腺癌，２０例胆囊腺瘤和３例正常的胆囊上皮ＤＮＡ含量，并用ＡＢＣ免疫组化法对ＰＣＮＡ进行了测定。结果：（１）细胞核ＤＮＡ含量、异型性和ＰＣＮＡ指数在正常胆囊上皮－异型增生－腺瘤恶变－胆囊腺癌中逐渐增加；（２）胆囊腺瘤中异倍体比例与胆囊腺瘤的大小、合并胆囊结石有明显的关系（Ｐ＜００５），而与腺瘤数目、组织学类型无关。ＰＣＮＡ指数与腺瘤的大小有关，与腺瘤数目及组织学分类无关。结论：胆囊腺瘤具有明显的癌变潜能，腺瘤的直径≥１ｃｍ和伴有胆囊结石时癌变机率更大，应早期手术治疗     

从中国非甲—庚型肝炎病人中克隆到TT病毒样DNA序列

从中国非甲－庚型肝炎病人中克隆到ＴＴ病毒样ＤＮＡ序列张军１杨海杰１苏智军２张奕返２林长青１黄鹤１郭庆１王颖１曾定１夏宁邵１（１厦门大学肿瘤细胞工程国家专业实验室厦门３６１００５２福建省泉州市第一医院泉州３６２０００）肝炎是严重危害我国人民身体健康的疾...     

Retrotransposable elements in the Dictyostelium discoideum genome

Repetitive DNA is a major component of any living cell. In eukaryotes retrotransposable elements make up several percent of the genome size, and consequently, retroelements are often identified in experiments aimed at establishing physical maps and whole genome sequences. In this review, recent progress in the characterization of retrotransposable elements in the genome of the eukaryotic mi croorganism Dictyostelium discoideum is summarized with a focus on retroelements which integrate near transfer RNA genes with intriguing position specificity. Received 21 November 1997; received after revision 6 January 1998; accepted 6 January 1998     

Y-family DNA polymerases in mammalian cells

Eukaryotic genomes are replicated with high fidelity to assure the faithful transmission of genetic information from one generation to the next. The accuracy of replication relies heavily on the ability of replicative DNA polymerases to efficiently select correct nucleotides for the polymerization reaction and, using their intrinsic exonuclease activities, to excise mistakenly incorporated nucleotides. Cells also possess a variety of specialized DNA polymerases that, by a process called translesion DNA synthesis (TLS), help overcome replication blocks when unrepaired DNA lesions stall the replication machinery. This review considers the properties of the Y-family (a subset of specialized DNA polymerases) and their roles in modulating spontaneous and genotoxic-induced mutations in mammals. We also review recent insights into the molecular mechanisms that regulate PCNA monoubiquitination and DNA polymerase switching during TLS and discuss the potential of using Y-family DNA polymerases as novel targets for cancer prevention and therapy.     

Collaborative multi-agent reinforcement learning based on experience propagation

For multi-agent reinforcement learning in Markov games, knowledge extraction and sharing are key research problems. State list extracting means to calculate the optimal shared state path from state trajectories with cycles. A state list extracting algorithm checks cyclic state lists of a current state in the state trajectory, condensing the optimal action set of the current state. By reinforcing the optimal action selected, the action policy of cyclic states is optimized gradually. The state list extracting is repeatedly learned and used as the experience knowledge which is shared by teams. Agents speed up the rate of convergence by experience sharing. Competition games of preys and predators are used for the experiments. The results of experiments prove that the proposed algorithms overcome the lack of experience in the initial stage, speed up learning and improve the performance.     

Improving DNA damage repair ability ofE. coli to UV-radiosensitivity by DNA-mediated gene transfer of low energy ion beam

Using calcium chloride method of transfer gene as control, a new technique of transferring gene by low energy ion beam has been applied to the study of improving DNA damage repair ability ofE. coli to UV-radiosensitivity. The genome DNA pieces ofDeinococcus radiodurans, as “foreign” genetic materials, were introduced into the UV-radiosensitive strains ofE. coli by implantation of 20 keV Ar⁺ at doses ranging from 1 × 10¹⁵ to 2 × 10¹⁵ ions/cm². Results show that the transfected strains present higher UV-radioresistance than that of un-transfected ones and start ones. The survival rate of transfected strains and their unscheduled DNA synthesis (UDS) ability is increased, indicating that the transfer gene is a success.     

Menadione-induced apoptosis and the degradation of lamin-like proteins in tobacco protoplasts

Detection of stereotypic hallmarks of apoptosis during cell death induced by menadione, including DNA laddering and the formation of apoptotic bodies, is reported. Comet assay and the TdT-mediated dUTP nick end labelling (TUNEL) procedure were also performed to detect DNA fragmentation. Inhibition of DNA fragmentation by Ac-Asp-Glu-Val-Asp-aldehyde (Ac-DEVD-CHO) and phenylmethylsulfosyl (PMSF) implicated the involvement of caspase-like proteases in menadione-induced apoptosis in plants. We further studied the cleavage of lamin-like proteins during apoptosis in menadione-treated tobacco protoplasts. In animals, it has been reported that the solubilization of nuclear lamina and lamin degradation occurs during apoptotic cell death. However, little is known about the fate of lamins in apoptotic plant cells. Our study provided evidence that lamin-like proteins degraded into 35-kDa fragments in tobacco protoplasts induced by menadione, and this preceded DNA fragmentation. The results thus indicated that proteolytic cleavage of nuclear lamins was also conserved in programmed cell death in plants. Received 16 November 1998; received after revision 21 December 1998; accepted 23 December 1998     

The Technology Parameters Optimization of Extracting Natural Cellulose Fibers from Eulaliopsis Binata

The extracting process and parameters optimization of Eulaliopsis binata fibers were studied.The components of Eulaliopsis binata were tested,the cellulose contents was about 45%,and the lignin content was as high as 18.5%.And the components of Eulaliopsis binata fibers were compared with some bast fibers.The analysis of physical and chemical properties related to acid,alkali,and auxiliary agent about cellulose and pectin,and lignin components in Eulaliopsis binata fibers were investigated.The chemical proc...     

细胞膜渗透性实验的改进及鸡血液DNA的提取

以成年鸡血为材料,分析了不同浓度NaCl、NH4Ac、乙醇、葡萄糖条件下鸡红细胞的渗透性;采用盐析法和碘化钾（KI）法提取鸡血细胞DNA,用二苯胺法和紫外分光法鉴定DNA提取效果。结果表明,在低渗、等渗、高渗溶质中,乙醇渗入细胞的速度都是最快的;用二苯胺法检测从鸡血液中提取的DNA,发现盐析法提取的DNA颜色反应较碘化钾法深;盐析法和碘化钾法提取DNA的光吸收值比率分别为1.6～2.0和1.8～2.0,产量分别为0.7×10-6～0.9×10-6 g/L和0.4×10-6～0.6×10-6 g/L。     

循环经济的“和谐DNA”

DNA通常被称为遗传微粒，其中带有遗传信息的片段称为基因。 DNA是一事物之所以是该事物的决定性因素。按照基因图谱理论分析循环经济，可以发现其中蕴含的“和谐DNA”：任何经济系统都以特定的发展哲学作指导，而循环经济的发展哲学是和谐哲学；任何经济系统都有特定的增长要诀，而循环经济的生产增长密码是和谐生物；循环经济之奥在于循环，而循环周流之道即和谐往复之道；从某种意义上说，循环经济即和谐经济；循环经济的文明指归当属和谐文明。正因为循环经济内涵着“和谐DNA”，故发展循环经济是和谐发展、科学发展的应有之义。