人细胞差异表达基因cDNA消减杂交体系的建立

为克隆肺腺癌分化相关基因, 采用诱导分化与消减杂交相结合的策略, 建立了全反式维甲酸(RA)诱导前后人肺腺癌细胞系的cDNA消减文库, 得到124个cDNA消减克隆. 经加减法杂交差异筛选、DNA和RNA印迹、cDNA全序列测定和生物学功能分析, 分离到3个在人肺腺癌细胞系分化过程中由RA激活而特异表达的新的cDNA序列这一策略和技术路线适用于分离细胞中呈过量表达或表达抑制基因的cDNA克隆, 并具有反映细胞分化过程中基因表达动态变化特征和相对简便适用的特点.     

具有竞争指针的短时记忆神经网络模型

在我们以前提出的短时记忆神经网络模型基础上［３］,我们在新模型中引入突触竞争机制,提出了一个新的短时记忆神经网络模型。模型仍由两个神经网络所组成;其一为与长时记忆共有的信息内容表达网络,另一个为指针神经元环路。由于表达区神经元与指针神经元间的突触权重的竞争,使得模型可以表现出由干扰引起的短时记忆的遗忘。相应于自由回忆序列位置效应和汉字组块两个心理学实验,对模型做了计算机仿真。仿真结果显示模型的行为与两个心理实验定量地符合得很好。由此表明现在的模型更合适于作为短时记忆的模型。     

宜昌大老岭种子植物区系研究

大老岭有野生种子植物１２２科４３５属８５６种。对本区科、属和种进行了统计与分析,结果表明,该地区的植物区系性质明显是温带性,且以北温带成分为主,地理成分复杂,仅属就有１３个分布区类型和１７个变型,地理联系广泛,具有古老性强和特有现象不很突出的特点。     

生物种群动态微分方程模型参数估计方法

本文以数值分析和最优化技术的有机结合为基础,提出了一种新的对动态微分方程模型直接进行数据拟合和参数估计方法,并以Logistic微分方程、生物种间竞争关系微分方程以及一种复合形态的Logistic微分方程为例进行了数据拟合试验．结果表明,该方法对各种动态微分方程模型均能进行最优拟合分析并求解其参数．同时发现,以前有的作者〔1,2,3,4,5〕提出的方法所得到的参数估计值存在系统误差且误差较大．     

棉铃虫乙酰胆碱酯酶的底物专一性和发育期变化(英)

通过对河北省邯郸地区和山东省冠县的棉铃虫(Helicoverpa armigera H(?)bner)乙酰胆碱酯酶(AChE)研究,结果表明,棉铃虫乙酰胆碱酯酶对乙酰硫代胆碱(ATCh)和乙酰-β-甲基硫代胆碱(MeTCh)的比活力以及米氏常数(K_(?))值随其发育阶段呈有规律的变化,AChE比活力在幼虫期呈现两个高峰,一个在三龄,另一个在化蛹前;在蛹期AChE比活力没有明显的变化,而且比活力值比较低;到成虫期第4天有一个明显的高峰,比活力值高于其它任何虫态。K_(?)和最大反应速度(V_(max))的变化趋势基本上与比活力一致。棉铃虫AChE的K_(?)和比活力随其生长发育阶段的周期性变化对于指导用有机磷和氨基甲酸酯类杀虫药剂的化学防治具有重要的意义。不同地点采集到的棉铃虫AChE对AICh和MeTCh水解的活化能有所不同,邯郸地区的棉铃虫AChE水解MeTCh的活化能,蛹和成虫是幼虫期的3.9-4.3倍,而冠县棉铃虫水解MeTCh的活化能则变化不大。AChE水解ATCh的活化能,邯郸地区棉铃虫的AChE不同虫态间变化不大,冠县棉铃虫AChE,幼虫和成虫期约是蛹期的4倍。这说明不同生长发育时期,棉铃虫AChE对底物的水解所消耗的能量是不同的。棉铃虫幼虫AChE的最适反应条件是酶量以重量计为50-100mg,反应时间为10-20min,反应温度为35℃,反应体系的pH值为8.0。     

悬钩子属种质的评价

在进行了７省悬钩子资源调查的基础上,在南京建立了悬钩子属田间基因库。３年来对田间基因库内保存并开花结果的３０个种进行了开花结果性状的记栽和评价。内容包括果实特征,糖、酸、维生素类、氨基酸、矿质元素含量分析,染色体计数等。分析了种间和种内多样性物存在及在良种选育中利用的可能性。     

胁迫处理对林生山黧豆蛋白质多肽及其含量的影响

应用二维电泳技术,分析了经水分胁迫（ＰＥＧ）、盐分胁迫（ＮａＣｌ）和热激（４０℃）处理后林生山黧豆（ＬａｔｈｙｒｕｓｓｙｌｖｅｓｔｒｉｓＬ．）体内蛋白质多肽及其含量的变化。有些蛋白质经ＰＥＧ、ＮａＣｌ和热激处理后可以产生相同的变化。两种不同的胁迫因子对某些蛋白质的影响有一定的共同性。特定的胁迫条件可以造成特定的影响。不同胁迫因子对同一蛋白质多肽可以造成不同的影响。胁迫下蛋白质的变化可能与林生山黧豆抵抗和适应胁迫条件的能力以及体内非蛋白质氨基酸的代谢有关     

人乳腺癌cAMP结合蛋白

建立了测定人乳腺癌胞浆ｃＡＭＰ结合蛋白（ｃＡＭＰｂ．ｐ．）方法。综合研究了其温度、保温时间、配体浓度、稳定性等条件。ｃＡＭＰｂ．ｐ．的Ｋ_Ｄ值为２．９０×１０~（－８）ｍｏｌ／Ｌ．并测定了６０例雌激素受体（ＥＲ）Ｆｕ性乳腺癌标本的ｃＡＭＰｂ．ｐ．含量。此组病人术后均接受系统的内分泌治疗,ＥＲ／ｃＡＭＰｂｐ,比值范围为７．７～３６２×１０~（－３）,ＥＲ／ｃＡＭＰｂ．ｐ．比值≥４０×１０~（－３）的五年生存率明显高于比值＜４０×１０~（－３）组,（ｐ＜０．００５）．表明测定ＥＲ／ｃＡＭＰｂ．ｐ．比值对预测患者内分泌治疗疗效,优于单独测定ＥＲ．     

Characterization of a Chlamydomonas reinhardtii gene encoding a protein of the DNA photolyase/blue light photoreceptor family

The organization and nucleotide sequence of a gene from Chlamydomonas reinhardtii encoding a member of the DNA photolyase/blue light photoreceptor protein family is reported. A region of over 7 kb encompassing the gene was sequenced. Northern analysis detected a single 4.2 kb mRNA. The gene consists of eight exons and seven introns, and encodes a predicted protein of 867 amino acids. The first 500 amino acids exhibit significant homology with previously sequenced DNA photolyases, showing the closest relationship to mustard (Sinapis alba) photolyase (43% identity). An even higher identity, 49%, is obtained when the Chlamydomonas gene product is compared to the putative blue-light photoreceptor (HY4) from Arabidopsis thaliana. Both the Chlamydomonas and the Arabidopsis proteins differ from the well characterized DNA photolyases in that they contain a carboxyl terminal extension of 367 and 181 amino acids, respectively. However, there is very little homology between the carboxyl terminal domains of the two proteins. A previously isolated Chlamydomonas mutant, phrl, which is deficient in DNA photolyase activity, especially in the nucleus, was shown by RFLP analysis not to be linked to the gene we have isolated. We propose this gene encodes a candidate Chlamydomonas blue light photoreceptor.     

Substrate requirements for ErmC' methyltransferase activity.

ErmC' is a methyltransferase that confers resistance to the macrolide-lincosamide-streptogramin B group of antibiotics by catalyzing the methylation of 23S rRNA at a specific adenine residue (A-2085 in Bacillus subtilis; A-2058 in Escherichia coli). The gene for ErmC' was cloned and expressed to a high level in E. coli, and the protein was purified to virtual homogeneity. Studies of substrate requirements of ErmC' have shown that a 262-nucleotide RNA fragment within domain V of B. subtilis 23S rRNA can be utilized efficiently as a substrate for methylation at A-2085. Kinetic studies of the monomethylation reaction showed that the apparent Km of this 262-nucleotide RNA oligonucleotide was 26-fold greater than the value determined for full-size and domain V 23S rRNA. In addition, the Vmax for this fragment also rose sevenfold. A model of RNA-ErmC' interaction involving multiple binding sites is proposed from the kinetic data presented.