新疆亚鳞木（比较种）角质层特征

报道了产自江苏宜兴晚泥盆世五通组新疆亚鳞木（比较种）Ｓｕｂｌｅｐｉｄｏｄｅｎｄｒｏｎ ｃｆ． ｘｉｎｊｉａｎｇｅｎｓｅＳｕｎ）的表皮角质层用荧光分析显示的特征．该种茎干表皮角质层覆于叶座及叶座间隔带,其中间隔带角质层厚于叶座．表皮细胞在间隔带与叶座表现特征不同．间隔带中部,表皮细胞呈纵长的多边形,其纵长方向与茎干延伸方向相同,细胞壁略有弯曲．间隔带靠近叶座之表皮细胞,细胞壁直,形状类似于前者;但大小仅为前者的１／２左右,且其纵长方向逐渐向叶座边缘偏转．叶座表皮细胞呈近等多边形,有胞间隙．该种茎表皮无气孔     

Outline structure of the human L1 cell adhesion molecule and the sites where mutations cause neurological disorders.

The L1 cell adhesion molecule has six domains homologous to members of the immunoglobulin superfamily and five homologous to fibronectin type III domains. We determined the outline structure of the L1 domains by showing that they have, at the key sites that determine conformation, residues similar to those in proteins of known structure. The outline structure describes the relative positions of residues, the major secondary structures and residue solvent accessibility. We use the outline structure to investigate the likely effects of 22 mutations that cause neurological diseases. The mutations are not randomly distributed but cluster in a few regions of the structure. They can be divided into those that act mainly by changing conformation or denaturing their domain and those that alter its surface properties.     

Molecular cloning of a metallothionein-like gene from Nicotiana glutinosa L. and its induction by wounding and tobacco mosaic virus infection.

The cloning and characterization of genes expressed in plant disease resistance could be an initial step toward understanding the molecular mechanisms of disease resistance. A metallothionein-like gene that is inducible by tobacco mosaic virus and by wounding was cloned in the process of subtractive cloning of disease resistance-response genes in Nicotiana glutinosa. One 530-bp cDNA clone (KC9-10) containing an open reading frame of 81 amino acids was characterized. Genomic Southern blot hybridization with the cDNA probe revealed that tobacco metallothionein-like genes are present in few or in one copy per diploid genome. Northern blot hybridization detected strong induction of a 0.5-kb mRNA by wounding and tobacco mosaic virus infection, but only mild induction was detected when copper was tested as an inducer. Methyl jasmonate, salicylic acid, and ethylene were also tested as possible inducers of this gene, but they had no effect on its expression. The possible role of this gene in wounded and pathogen-stressed plants is discussed.     

Identification of two glutaminases inRhizobium etli

We present evidence thatRhizobium etli has two glutaminases differentiated by their thermostability and electrophoretic mobility. The thermostable glutaminase (B) is constitutive, in contrast with the thermolabile glutaminase (A), which is positively regulated by glutamine and negatively regulated by ammonium and by the carbon source. In distinction to glutaminase A, glutaminase B plays a minor role in the utilization of glutamine as a carbon source, but it may play a role in maintaining the balance of glutamine and glutamate. By complementation of theRhizobium etli LM16 mutant that lacks glutaminase A, we have cloned the gene that codes for this enzyme.     

The Human Serum Paraoxonase/Arylesterase Gene (PON1) Is One Member of a Multigene Family

A physiological role for paraoxonase (PON1) is still uncertain, but it catalyzes the hydrolysis of toxic organophosphates. Evidence that the human genome contains twoPON1-like genes, designatedPON2andPON3,is presented here. HumanPON1andPON2each have nine exons, and the exon/intron junctions occur at equivalent positions.PON1andPON2genes are both on chromosome 7 in human and on chromosome 6 in the mouse. Turkey and chicken, like most birds, lack paraoxonase activity and are very susceptible to organophosphates. However, they have aPON-like gene with 70% identity with humanPON1, PON2,andPON3.Another unexpected finding is that the deduced amino acid sequences of PON2 in human, mouse, dog, turkey, and chicken and of human PON3 are all missing the amino acid residue 105, which is lysine in human PON1. The expanded number ofPONgenes will have important implications for future experiments designed to discover the individual functions, catalytic properties, and physiological roles of the paraoxonases.     

畜禽遗传资源系统保存的理论与模拟实验研究──I．畜禽遗传资源系统保存的理论分析

本文提出了畜禽遗传资源系统保存的概念、基本思想及其群体遗传结构变化的数学模型。该理论是将一定时空内某一畜种所拥有的全部基因作为保存对象,既将活体保存作为基本方法,又将其有机地与高新生物技术结合在一起;既追求系统地保存控制畜种特性的基因资源,又可达到保存地方品种的目的。在假定无世代重叠,群体内存在选择、突变、迁移,且考虑漂变效应的情况下,本文所构建的两个数学模型可分别用来描述一个座位上多个主基因频率或数量性状群体均数的动态变化。     

兔出血症病毒主要结构多肽的氨基酸分析

兔出血症病毒主要结构多肽的氨基酸分析王恒安,杜念兴,徐为燕（南京农业大学,南京２１００９５）关键词兔出血症病毒,结构多肽,氨基酸分析有关兔出血症病毒（ＲＨＤＶ）结构多肽的报道很多,有认为只有１条,有报道４条的,也有报道多达６条的。但其主要结构多肽为分...     

一种“无血清”培养基对肿瘤细胞生长的支持

本文报告一种为适于杂交瘤细胞生长“无血清”培养基－适量的成牛血清低分子成分超滤液、１０ｍｇ／Ｌ转铁蛋白（Ｔ）、１０ｍｇ／Ｌ胰岛素（Ｉ）、２０μｍｏｌ／Ｌ乙醇胺（Ｅ）、４０ｎｍｏｌ／Ｌ硒酸钠（Ｓ）等诸补充成分替代胎牛血清加到基础液中－也完全适用于培养肿瘤细胞,且观察到与之相似的规律性结果,癌细胞在本“无血清”培养若的生长水平达到在含胎牛血清培养基中生长的水平。对于癌细胞的生长,ＬＭＷ－ＣＳ与Ｔ、Ｉ、     

新疆地区小麦白粉病菌寄主范围的研究

用小麦白粉病菌11个生理小种的混合菌种,对新疆地区的小麦近缘植物的7个属22个种的47份材料进行接种,除6份免疫外,其余均接种成功.用其中6个属19个种的29份小麦近缘植物产生的白粉病菌,对小麦回接,参试的29份材料全部回接成功.小麦白粉病菌对小麦近缘植物的寄生像在小麦上一样,有明显的寄生专化性.感病的小麦近缘植物的78.0%对小麦白粉病菌的感病性,随生育期增长而急剧下降.文中并对小麦白粉病中间寄主的作用进行了讨论.