呼吸缺陷型酵母菌株的离子束辐射敏感性研究

选取一株由离子束辐照诱变获得的呼吸缺陷型酵母菌株，研究其在不同离子辐照剂量范围的辐射敏感性。结果发现，呼吸缺陷型酵母菌株因其线粒体及线粒体DNA发生突变，在离子束辐照时，在低剂量区域表现出较高辐射敏感性，在高剂量区则表现出对于辐射的抗性。     

γ射线对肝癌细胞G2染色体的原初损伤

用Calyculin—A诱导的早熟染色体凝集技术研究了γ射线诱导人肝癌细胞株HepG2细胞G2期染色体的原初损伤。结果表明:G2等点染色单体断裂畸变与辐射剂量呈线性平方关系,G2染色单体断裂畸变和G2期染色单体断裂畸变总数与辐射剂量呈线性正相关关系,发生各类断裂畸变的细胞率与剂量也呈线性正相关关系。γ射线诱发的断裂畸变主要是G2染色单体断裂畸变,断裂畸变的细胞主要是发生G2染色单体断裂畸变。A chemically induced premature chromosome condensation technique with Calyculin-A has been employed to estimate the initial chromosome damage in HepG2 condensed in G2 phase and the percentage of aberrant cells after exposure to γ-rays. The results show that the dose-response for iso-chromatid breaks is linear-quadratic manner, while chromatid-type breaks and total chromatid breaks show a positive linear dose-response. The percent tages of all kinds of aberrant cells are increasing linearly with increasing doses. G2 chromatid-type breaks and the percentage of G2 chromatid-type aberrant cells are predominate in G2 total chromatid breaks induced b y γ-rays.     

γ射线对A172胶质瘤细胞的生物学效应

以不同剂量照射后的细胞存活率、 微核率和微核细胞率作为生物学终点, 研究了γ射线对A172细胞的生物学效应. 结果表明: 细胞存活率与剂量之间满足回归方程lgY=-0.064 27X+1.833 54, 其回归系数r=-0.988 6, P<0.01. 剂量为1 Gy时微核率和微核细胞率达到最大值, 此时的微核率为（66.75±3.564）%, 微核细胞率为（53.9±0.784 9）%, 微核率和微核细胞率均随着剂量的增大先增大后减小, 并分别维持在42%和37%左右. To study the biological effectiveness in A172 glioma cells induced by γ ray irradiation, the survival fraction and the micronucleus frequency of A172 cells was measured. The result showed that the survival fraction was negatively correlated to the radiation dose. At 1.0 Gy, the micronucleus frequency peaked about (66.75±3.564)%, and the frequency of micronucleus cells peaked about (53.9 ±0.784 9)%. As the radiation dose increasing, the micronucleus frequency and the frequency of micronucleus cells decreased and finally kept steady about 42% and 37%, respectively.     

适用于高通量筛选的氢化可的松生物转化率快速检测方法研究

以浓硫酸显色反应为基础,通过分光光度计可见光双波长法测定氢化可的松转化率。利用朗伯比尔定律,结合三维数据建模二阶校正,建立了氢化可的松生物转化率的快速测定方法,回收率为96.9%~110.8%。验证实验显示,其测定结果与药典方法(高效液相色谱)具有很高的一致性,能够满足菌种高通量初筛检测的需求。该研究在该菌种高通量选育方面有良好的应用前景。     

低能离子注入小麦种子胚内的射程分布

采用110keV56Fe1+离子束垂直注入小麦种胚后,将小麦沿腹面的纵沟掰开,形成剖面,将剖面水平朝上粘贴在金属铜托上,用扫描电镜在剖面上从胚表面向纵深进行点分析,测定不同深度上由Fe元素激发出的特征X射线强度,由此得到了该种离子注入小麦胚内的最大射程约5μm,最可几射程为0.935μm.并对这种低能离子注入作物种子能诱发突变的机理进行了详细讨论. After embryo of wheat seed was right implanted by 110 keV 56Fe1+ions, the seed was broken into two parts by hand along its abdomen trench to form two cross sections. A half seed was pasted on a metal holder in keeping the cross section upwards horizontal. Spot analyses were carried out from embryo surface towards depth on the cross section under SEM and the intensity of characteristic X rays induced by electrons in Fe elements of the embryo was measured. From this, the maximum range of the ionsi...     

重离子诱导的质粒DNA双链断裂分布研究

利用能量为7．2MeV／u氖离子束辐照体外质粒DNA:pUC18，采用恒场凝胶电泳结合多功能荧光成像系统研究了pUC18双链断裂片段的分布。证实了双链断裂片段分布的非随机性，结果还发现DNA断裂后片段的交联现象，而且交联片段的分布也是非随机的。DNA is considered to be the most important and sensitive target in biological systems. In addition to the base damage, DNA strand breaks are the major lesion in the genome due to exposure to ionizing radiation. Mutation can be introduced to DNA as a result of enzymatic processing of DNA lesions or post irradiation replication. However, the mechanisms of radiation induced mutations are not well clarified at the molecular level. To study the effect on the simple plasmid DNA of heavy ion is even predominant or more feasible. Plasmid pUC18 DNA was prepared and irradiated by neon beam (7.199 MeV/u). The fragment distributions were determined by quantifying the ethidium bromide fluorescence. It can be seen that the shape of the intensity distributions is vastly different for the used radiation Dose. The distribution produced shows an excess of fragments particularly in 3 000 and 10 000 Gy the size range between 20—40 kbp and 20—50 bp. This clustering of double stranded fragments might be influenced by the higher order chromatin structure of genomic DNA. If so, DNA loop structures could correspond to the size range for which we observed DSB clustering. Further studies aim at elucidating the heterogeneity of DSB induction within the genome and investigate the influence of chromatin structure on the non random fragment distribution.     

12C6+离子辐照小鼠Lewis肿瘤的研究

研究了HIRFL提供的12C6+离子辐照C57BL/6J小鼠右后腿移植的Lewis肿瘤的生长延迟和碳离子辐照对Lewis肿瘤小鼠寿命的延长.结果表明,碳离子照射的小鼠肿瘤生长体积明显地小于对照的体积.在剂量相同、分次数辐照越多时,肿瘤生长就越缓慢,肿瘤抑制就越高.在辐照分次数相同时,不同剂量对受照肿瘤生长体积未产生差异.在4Gy×3,8Gy×3和12Gy×2组3种辐照剂量下,小鼠寿命的P值小于0.05;可知小鼠的寿命延长具有统计学意义. Growth delay of the transplantable Lewis tumors growing in right hind legs of C(57) BL/6J mice and life prolongation of the mice with Lewis tumors were investigated after()~(12)C~(6+) ion radiation at HIRFL. The results show that growth volumes of the mouse tumors following carbon radiation are distinctly less than control during 21 days; the more fractions of radiation with same doses, the slower growth of tumors and the higher inhibition of tumors; different doses with the same fractions of radiation ...