过氧化物酶活性与烟草脉坏死病抗性的关系

测定了接种马铃薯Y病毒脉坏死株系后转PVY－N1b基因的抗性烟草NC89和非转基因敏感烟草NC89的叶片组织透性和过氧化物酶活性,并对过氧化物酶同工酶进行了电泳分析,结果表明：抗、敏烟草叶片的组织透性与叶片内过氧化物酶活性的变化趋势一致,两者在接种后均呈增高趋势,且敏感烟草的增高幅度明显高于抗性烟草;接种后,两者的过氧化物酶同工酶均出现了一条新酶谱,抗性烟草植物的新酶带在接种后第2天开始出现,而敏感烟草的新酶带则在接种后第6天开始出现,且活性明显强于抗性烟草。     

Evolvability of an RNA virus is determined by its mutational neighbourhood

The ubiquity of mechanisms that generate genetic variation has spurred arguments that evolvability, the ability to generate adaptive variation, has itself evolved in response to natural selection. The high mutation rate of RNA viruses is postulated to be an adaptation for evolvability, but the paradox is that whereas some RNA viruses evolve at high rates, others are highly stable. Here we show that evolvability in the RNA bacteriophage phi6 is also determined by the accessibility of advantageous genotypes within the mutational neighbourhood (the set of mutants one or a few mutational steps away). We found that two phi6 populations that were derived from a single ancestral phage repeatedly evolved at different rates and toward different fitness maxima. Fitness measurements of individual phages showed that the fitness distribution of mutants differed between the two populations. Whereas population A, which evolved toward a higher maximum, had a distribution that contained many advantageous mutants, population B, which evolved toward a lower maximum, had a distribution that contained only deleterious mutants. We interpret these distributions to measure the fitness effects of genotypes that are mutationally available to the two populations. Thus, the evolvability of phi6 is constrained by the distribution of its mutational neighbours, despite the fact that this phage has the characteristic high mutation rate of RNA viruses.     

甘薯贮藏特性及活性氧代谢的相关性分析

文章以多个具有不同贮藏特性的甘薯品种徐55-2、徐32、Z15-1、美99573、商薯9号、Sinjami、徐薯23、徐22-5、Z11-1、烟25为研究对象,考察了其块根贮藏特性的差异,并测定了甘薯叶片中抗氧化相关酶、脂氧合酶(LOX)、活性氧(ROS)及丙二醛(MDA)等指标,解析了它们之间的相关性.结果 表明:徐...     

两种蟋蟀同工酶的比较研究

用聚丙烯酰胺凝胶电泳方法分析石首棺头蟋（Ｌｏｘｏｂｌｅｍｍｕｓｅｑｕｅｓｔｒｉｓ）与泰康棺头蟋（Ｌ．ｔａｉｃｏｕｎ）的酯酶（ＥＳＴ）和苹果酸脱氢酶（ＭＤＨ）同工酶．两种蟋蟀的ＥＳＴ和ＭＤＨ同工酶酶谱极为相似．其中ＥＳＴ酶谱可分为４个区带组,推测受４个位点控制．因这两种蟋蟀的形态特征极为相似,两种同工酶酶谱也比较相似,而且控制ＥＳＴ的位点数相同,因此推测两者的亲缘关系比较接近,极有可能为近缘种     

X Window客户间通信在GSI录入系统中的应用

介绍了数字化仪在Linux操作系统下的驱动方案,通过X Window窗口系统下的客户间通信,实现了GIS录入系统主程序和数字化仪驱动两个进程的并行工作。     

Implications of fragile X expression in normal males for the nature of the mutation

The fragile site at Xq27, associated with a common form of X-linked mental retardation (XLMR), is expressed in a variable proportion of the peripheral lymphocytes of affected males when the cells are cultured under thymidylate stress (Td stress) produced by folate or thymidylate deprivation. Some clinically normal males--transmitting males--are known to carry and transmit the fragile X mutation and yet show no cytogenetic expression in lymphocytes. Normal males with no family history of X-linked mental retardation express the site only rarely. When the fragile X chromosome from affected males is isolated in a rodent genetic background by somatic cell hybridization, the level of expression is similar to that seen in lymphocytes under Td stress. Here we show that X chromosomes from two transmitting males and two normal control males, all of which were fragile X negative in lymphocytes or lymphoblasts, could be made to express the fragile site in hybrids, although at levels that were below those seen in hybrids from affected males. Furthermore, transmitting males could be differentiated from normal males by their significantly higher expression rates when hybrids were exposed to caffeine before cytogenetic harvest. One male chimpanzee also showed low level expression in hybrid cells. These data suggest that the hybrid system lowers the threshold for fragile X expression, a fragile site at Xq27 may be present on all human and chimpanzee X chromosomes and constitutes a previously unrecognized common fragile site and the hybrid system with caffeine post-treatment can distinguish between the common Xq27 fragile site of control males, the occult mutant fragile site of a transmitting male, and the fully expressed fragile site of an affected male with XLMR. Thus the mutation producing XLMR may represent a multi-step alteration of a naturally occurring DNA sequence producing a continuum of cytogenetic expression and a threshold for clinical manifestation.     

Conservation of position and exclusive expression of mouse Xist from the inactive X chromosome

X-chromosome inactivation in mammals is a regulatory phenomenon whereby one of the two X chromosomes in female cells is genetically inactivated, resulting in dosage compensation for X-linked genes between males and females. In both man and mouse, X-chromosome inactivation is thought to proceed from a single cis-acting switch region or inactivation centre (XIC/Xic). In the human, XIC has been mapped to band Xq13 (ref. 6) and in the mouse to band XD (ref. 7), and comparative mapping has shown that the XIC regions in the two species are syntenic. The recently described human XIST gene maps to the XIC region and seems to be expressed only from the inactive X chromosome. We report here that the mouse Xist gene maps to the Xic region of the mouse X chromosome and, using an interspecific Mus spretus/Mus musculus domesticus F1 hybrid mouse carrying the T(X;16)16H translocation, show that Xist is exclusively expressed from the inactive X chromosome. Conservation between man and mouse of chromosomal position and unique expression exclusively from the inactive X chromosome lends support to the hypothesis that XIST and its mouse homologue are involved in X-chromosome inactivation.     

福建与台湾蝴蝶物种多样性比较

本文比较了福建与台湾蝴蝶物种的多样性。研究表明,目前福建记载有蝴蝶种类11科515种,台湾记载有蝴蝶种类5科（含11科种类）408种。其中,福建和台湾共有的蝴蝶种类254种,分别占福建蝴蝶种类的49.32%和台湾蝴蝶种类的62.25%;福建分布而台湾未见的蝴蝶种类261种,占福建蝴蝶种类的50.68%;台湾分布而福建未见的蝴蝶种类155种,占台湾蝴蝶种类的37.99%。福建与台湾蝴蝶种类的分布差异约在40-50%。     

首发未治疗精神分裂症患者生活质量与精神症状的关联

为了探讨首发未用药的精神分裂症患者与接受治疗的精神分裂症患者之间的生活质量有无显著性差异,生活质量与精神分裂症症状之间是否存在关联,选取美国《精神疾病诊断与统计手册(第4版)》(DSM-IV)诊断明确的门诊和住院精神分裂症患者共99例,同时纳入年龄、文化程度无差异的健康对照57例;采用世界卫生组织(WHO)生存质量测定...     

饱和D最优设计法在马铃薯微繁培养基筛选中的应用

采用饱和D最优设计法,研究了5种植物生长调节剂与扦插个数的关系,通过记录青薯2号、6号两种脱毒试管苗生长状况,建立了不同植物生长调节剂、不同接种数对试管苗生长的函数模型。结果表明：试管苗最佳扦插个数：7—9个,2,4-D最佳浓度：1．32—2．514mg／L;6-BA最佳浓度：1．05—1．95mg／L;NAA最佳浓度：0．165—0．335mg／L;KT最佳浓度：0．35-0．65mg／L;CA最佳浓度：3．5～6．5mg／L。     

Tobacco curly shoot virus iso-lated in Yunnan is a distinct species of Begomovirus

Virus isolate Y1 was obtained from tobacco showing curly shoot symptoms in Baoshan, Yunnan Province. Whitefly transmission test and virion morphology observation showed that it is a begomovirus. In reactions with 14 monoclonal antibodies raised against begomoviruses, Y1 was readily differentiated from begomoviruses reported in China, Pakistan and India. The complete nucleotide sequence of DNA-A was determined, it contains 2746 nucleotides, with two ORFs in virion-sense DNA and four ORFs in complementary-sense DNA. Comparisons with total DNA-A, intergenic region and deduced amino acid sequences of individual ORFs showed that Y1 is a distinct Begomovirus species, for which the name Tobacco curly shoot virus (TCSV) is proposed. The total DNA-A of TCSV is most closely related to that of Tomato leaf curl virus from India (85% sequence identity). In contrast, the deduced coat protein of TCSV is most like that of Cotton leaf curl virus 72b isolate from Pakistan (98% amino acid sequence identity).