125I和65Zn在大蟾蜍体内的吸收与分布

利用同位素示踪法研究了不同引入途径的125I和65Zn在大蟾蜍体内的吸收与分布。无论采用注射还是灌喂的方法,蟾蜍对125I的残留动态差别不大,都可分为快清除期和平台期,0～2d为快清除期,3～7d为平台期,经过了快清除期之后,残留的125I约为起始量的8%,并维持到实验结束。注射了65Zn后,0～7d的吸收动态曲线有所起伏,但波动很小,其波动范围为102.4%～114.48%。表明大部分的65Zn仍留在体内,几乎没有排出体外。注射65Zn的转移并不明显。但灌喂65Zn的动态变化则大些,而且转移明显。其活度曲线出现阶段性下降,有两个下降期,第一个下降期为4h～3d,第二个下降期为5～7d。说明灌喂组对65Zn的转移比注射组的活跃,但在实验的第7d残留率仍在60%以上。     

Alterations in DNA methylation and genome structure in two rice mutant lines induced by high pressure

Pressure is expected to be an important parameter to affect characteristics of matters and control rate and equilibrium of chemical reactions. As a fundamental thermodynamic variable, it also has effects on bio-macromolecules and a lot of physiological an…     

Oligodendrocytes regulate formation of nodes of Ranvier via the recognition molecule OMgp

The molecular mechanisms underlying the involvement of oligodendrocytes in formation of the nodes of Ranvier (NORs) remain poorly understood. Here we show that oligodendrocyte-myelin glycoprotein (OMgp) aggregates specifically at NORs. Nodal location of OMgp does not occur along demyelinated axons of either Shiverer or proteolipid protein (PLP) transgenic mice. Over-expression of OMgp in OLN-93 cells facilitates process outgrowth. In transgenic mice in which expression of OMgp is down-regulated, myelin thickness declines, and lateral oligodendrocyte loops at the node-paranode junction are less compacted and even join together with the opposite loops, which leads to shortened nodal gaps. Notably, each of these structural abnormalities plus modest down-regulation of expression of Na(+) channel alpha subunit result in reduced conduction velocity in the spinal cords of the mutant mice. Thus, OMgp that is derived from glia has distinct roles in regulating nodal formation and function during CNS myelination.     

非线性动力学在脑电信号分析中的应用

EEG是由大脑产生的非线性时间序列,体现出混沌行为。近年来迅速发展的非线性动力学理论为脑电信号分析开创了一个新的领域。本文综述了近年来非线性动力学在脑电信号研究中（睡眠阶段,麻醉深度,认知过程,精神分裂,痴呆及癫痫）的进展,以期对脑神经动力学有更好的理解。     

淹水和干旱条件下水稻根系形成的QTLs及候选基因分析

为了研究不同水分条件下组成型根系性状和适应性根系性状的遗传机制,利用由IR64／Azucena发展的双单倍体（DH）群体分析了淹水和干旱条件下水稻幼苗种子根长（SRL）、不定根数（ARN）、总根干重（RW）及其对应的相对参数（干旱和淹水条件下根系性状的比值）的QTLs。淹水与干旱条件下检测到一个共同的种子根长QTL和一个共同的总根干重QTL。同时对前人发表的遗传群体定位的根系性状QTLs进行比较分析,检测到几个共同的根系性状QTLs。对与细胞伸长、分裂相关的候选基因进行了定位,其中4个细胞壁相关的ESTs（OsEXP2,OsEXP4,EXT和Xet）被定位在与不同水分条件下检测出的根系性状QTLs的相同区间。     

人IFN-β启动子基因报告质粒的构建及SARS-CoV3a和7a蛋白对IFN-β诱生作用的初步研究

3a蛋白和7a蛋白是SARS-CoV的非结构蛋白,分别主要由SARS基因组中ORF 3a 和ORF 7a所编码。在体内和体外感染病毒的细胞中均发现了有3a蛋白的表达。首先将pGL3-Control载体进行了改构,除去了SV40启动子基因,获得了pGL3-Enhancer载体,将获得的IFN-β启动子基因连入载体中,构建了带有人IFN-β启动子基因的荧光素酶报告质粒IP-21,并且通过实验证明所构建的质粒在干扰素的诱导剂NDV的作用下能够表达荧光素酶活性,照度计检测荧光素酶活性增强,从而验证了所构建的重组质粒的有效性。为了观察SARS-CoV非结构蛋白3a和7a对干扰素诱生途径的影响,将IP-21瞬转入稳定表达有3a和7a蛋白的CHO细胞,通过荧光素酶的信号强弱对3a和7a的作用进行分析,结果表明SARS-CoV的3a和7a蛋白能够刺激荧光素酶的表达,即在体外的细胞实验中,3a和7a能有效地激活IFN-β的启动子部分。此结果对进一步研究3a和7a的功能以及对SARS-CoV的致病机制的进一步研究有一定意义。     

PCR-RFLP and AP-PCR of rbcL and ITS of rDNA Show That × Taxodiomeria peizhongii (Taxodium x Cryptomeria) Is not an Intergeneric Hybrid

×Taxodiomeria peizhongiiZ. J. Ye, J. J. Zhang et S. H. Pan was regarded as a new intergeneric hybrid between Taxodium mucronatum Tenore (as the female donor) and Cryptomeria fortunei Hooibrenk ex Otto et Dietr (as the male donor). To confirm the authenticity of the intergeneric hybrid, we analyzed the rbcL gene and the internal transcribed spacer (ITS) of 26S-18S ribosomal RNA gene of the three species using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and arbitrarily primed PCR (AP-PCR), and obtained the following results: i) Taxodiomeria peizhongii had the same RFLP maps of the rbcL gene and the ITS as Taxodium mucronatum, but was different from C. fortunei; ii) a 311-bp PCR amplification product was obtained in C. fortunei by AP-PCR of ITS, but was not found in Taxodiomeria peizhongii. Our results have demonstrated that C. fortunei did not provide any genome for Taxodiomeria peizhongii, implying that T. peizhongii is not an intergeneric hybrid between the two species.     

Genotyping the Heading Date of Male-Sterile Rice Line II-32A

II-32A, an elite male-sterile line of rice （Oryza sativa L.）, has been widely used for the production of hybrid rice seed In China. Heading date In most combinations using II-32A shows transgressive Inheritance or similarity to the latter parent, but the genotype of II-32A with respect to major genes for heading time Is unknown. This limits the further exploitation of this sterile line In breeding and hybrid seed production. Using a number of major gene heading date Isogenlc lines and heading date QTL near-lsogenic lines, we genetically analyzed II-32B under both long- and short-day conditions. We show that II-32B carries two photoperlod-sensltlve genes, E1 and E3, a recessive late-heading gene, ef-l, and a photoperlod-sensltlve allele, Se-1^u. In addition we Identified In II- 32B a recessive Inhibitor for E1 or Se-1^n and other modified photoperlod-sensltlve genes. The heading-date constitution of II-32A was determined to be E1e2E3Se-1^uef-li-Se-1.     

Characterization of hepatic drug-metabolizing activities of Bama miniature pigs (Sus scrofa domestica): comparison with human enzyme analogs

We used various substrates and selective inhibitors of human cytochrome P450 (CYP) isozymes as probes to study the metabolism of liver microsomes from Chinese Bama miniature pigs. Nifedipine oxidation (NOD) and testosterone 6beta-hydroxylation (6beta-OHT) activities were similar between human liver microsomes and those from Bama miniature pigs. However, compared with those from humans, liver microsomes from Bama miniature pigs showed decreased phenacetin O-deethylation, coumarin 7-hydroxylation, and chlorzoxazone 6-hydroxylation activities, whereas dextromethorphan O-demethylation activity was increased. Ketoconazole selectively inhibited NOD and 6beta-OHT activities in microsomes from Bama pigs, and 8-methoxypsoralen and tranylcypromine inhibited coumarin 7-hydroxylation in pig microsomes. However, furafylline and quinidine failed to selectively inhibit phenacetin O-deethylation and dextromethorphan O-demethylation in microsomes from Bama pigs, whereas chlormethiazole more efficiently inhibited coumarin 7-hydroxylation activity than chlorzoxazone 6-hydroxylation in pig microsomes. Our results suggest that liver microsomes from Chinese Bama miniature pigs are similar to those from humans in regard to metabolism of nifedipine and testosterone (both are probe substrates for human CYP3A4). In addition, chemical inhibitors used as specific probes for human P450 enzymes did not always show the same selectivity toward corresponding enzyme activities in liver microsomes from Bama pigs. However, ketoconazole (a potent inhibitor of human CYP3A4) could be used as a selective inhibitor probe for the NOD and 6beta-OHT activities in liver microsomes from Chinese Bama miniature pigs.