植物转基因方法及特点和转基因沉默现象

本文概述和比较了植物转基因方法、特点和在转基因中出现的基因沉默现象及其机制     

刍议高职教育旅游人才培养的目标定位和调适——以广东女子职业技术学院旅游管理专业为例

大批旅游专业学生没能进入旅游业工作,而旅游业内又严重缺乏高素质的技能型旅游专业人才,这对矛盾长期困扰和制约着旅游业的发展。因而,高职教育人才培养的基础命题不是升级而是定位,只有切实做好人才培养目标的定位和调适,以上困扰才有望破解。     

货币政策规则之通货膨胀钉住综述

在通货膨胀钉住的货币政策动态优化问题中,本文主要从模型框架、货币政策规则的选择和设计、最优性、前瞻性等方面进行综述。介绍了货币政策规则和绩效评价等方面趋势,在模型参数不确定性条件下给出了最优的利率反应函数,以及讨论我国货币政策在新形势下存在的问题和面临的可能选择。     

Targeting of human aFGF gene into silkworm,Bombyx mori L. through homologous recombination

INTRODUCTION Transgenic technology developed over the 20years, has become a common tool widely applied tolivestock species because it is technically quitesimple, requiring only the injection of ‘naked’DNA into the nucleus of a fertilized eggs (Hammeret al., 1985; Suraokar and Bradley, 2000). Howeverthis technique has limitations in that the injectedDNA integrates randomly into the genome and thuscould not be expressed in the desired tissue or at theappropriate level. More impor…     

通过同源三倍体固定水稻杂种优势的新设想

文章提出了通过利用无融合生殖基因和培育同源三倍体来固定水稻杂种优势的新设想，指出了这一新设想的两大优点和急待解决的４大问题。笔者认为，通过常规育种手段将无融合生殖基因引入同源三倍体遗传组成中将可望消除其有性胚，而通过无性胚的产生来保持其遗传组成的相对稳定，进而可以达到固定水稻杂种优势的目的。     

Characterization of enhancer trap and gene trap harboring Ac/Ds transposon in transgenic rice

Insertion mutagenesis has become one of the most popular methods for gene functions analysis. Here we report a two-element Ac/Ds transposon system containing enhancer trap and gene trap for gene tagging in rice. The excision of Ds element was examined by PCR amplification. The excision frequency of Ds element varied from 0% to 40% among 20 F2 populations derived from 11 different Ds parents. Southern blot analysis revealed that more than 70% of excised Ds elements reinserted into rice genome and above 70% of the reinserted Ds elements were located at different positions of the chromosome in rice. The result of histochemical GUS analysis indicated that 28% of enhancer trap and 22% of gene trap tagging plants displayed GUS activity in leaves, roots, flowers or seeds. The GUS positive lines will be useful for identifying gene function in rice.     

Study on the effect of doxorubicin on expressions of genes encoding myocardial sarcoplasmic reticulum Ca<Superscript>2+</Superscript> transport proteins and the effect of taurine on myocardial protection in rabbits

To investigate the effect of doxorubicin(DOX) on gene expression of the myocardial sarcoplasmic reticulum (SR) Ca²⁺ transport proteins and the mechanism of taurine(Tau) protecting cardiac muscle cells, 9 rabbits were injected with DOX, 8 rabbits with DOX and Tau, and 9 rabbits with normal saline. Cardiac function, concentration of calcium in cardiomycocytes (Myo [Ca²⁺] _i ), activity of SR Ca²⁺-ATPase (SERCA2a), level of SERCA2a mRNA and Ca²⁺ released channels (RYR2) mRNA were detected. The left ventricle tissues were observed by electron microscopy. The results showed that cardiac index, left ventricular systolic pressure, activity of SR Ca²⁺-ATPase and level of SERCA2a mRNA decreased, while Myo[Ca²⁺] _i increased in DOX-treated rabbits. DOX could not affect the level of RYR2 mRNA. Tau intervention could alleviate the increase of left ventricular diastolic pressure, Myo[Ca²⁺] _i and the decrease of SERCA2a mRNA induced by doxorubicin. The results suggested that downregulation of SERCA2a gene expression was an important mechanism of DOX-induced cardiomyopathy and that Tau could partially improve the heart function by reducing calcium overload and alleviating downregulation of SERCA2a mRNA.     

BP神经网络优化算法研究

为解决BP神经网络收敛速度慢和易陷入局部极小值的缺点,利用遗传算法(GA)和基因表达式编程(GEP)的各自特点,基于BP算法提出了两种改进算法:其一是GA-BP算法,即利用GA优化BP神经网络的权值和阈值;其二是GEP-BP算法,即利用GEP对BP网络进行调整,包括网络结构、权值和阈值。用样本数据进行了测试并与基本BP算法进行了比较,结果表明两种改进算法具有很强的可行性和高效性。     

Characterization of enhancer trap and gene trap harboring<Emphasis Type="Italic">Ac/Ds</Emphasis> transposon in transgenic rice

Insertion mutagenesis has become one of the most popular methods for gene functions analysis. Here we report a two-elementAc/Ds transposon system containing enhancer trap and gene trap for gene tagging in rice. The excision ofDs element was examined by PCR amplification. The excision frequency ofDs element varied from 0% to 40% among 20 F₂ populations derived from 11 differentDs parents. Southern blot analysis revealed that more than 70% of excisedDs elements reinserted into rice genome and above 70% of the reinsertedDs elements were located at different positions of the chromosome in rice. The result of histochemical GUS analysis indicated that 28% of enhancer trap and 22% of gene trap tagging plants displayed GUS activity in leaves, roots, flowers or seeds. The GUS positive lines will be useful for identifying gene function in rice. Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2002AA2Z1003)     

IGF-1基因多态性与骨骼肌性状的关系

运动员选材是竞技体育中取胜的关键之一.在后基因组时代,基因选材将成为运动选材的重要手段,而基因选材的前提是必须找到有效的基因标记.胰岛素样生长因子-1(IGF-1)是一种与肌肉、骨骼等组织的生长关系十分密切的小分子多肽,其基因上很可能存在运动能力分子标记.因此,以该基因为目标区域,进行了查找基因标记的尝试.用PCR-RFLP法检测了基因5'调控区单核苷酸多态(SNPs)情况,并用广义线性模型统计分析了多态性与肌肉性状的关系.结果显示:IGF-1基因5'调控区存在一个C-T转换突变,形成三种基因型,分别标记为:"-/-"、"-/ "、" / ".基因型与骨骼肌生长总量和肌纤维直径有着密切的关系,"-/-"基因型个体的胸部和腿部肌肉总量最高,与" / '基因型个体相比差异显著,P值分另q为0.029和0.038,而且"-/-"基因型个体的肌纤维平均直径最大,与" /-"基因型比差异显著(P＜0.05).