应用RAPD技术分析奥利亚罗非鱼和尼罗罗非鱼的基因多态性(英文)

以随机扩增多态ＤＮＡ技术（ＲＡＰＤ）分析了奥利亚罗非鱼和尼罗罗非鱼两个养殖群体的群体内及群体间遗传关系,并探讨了该技术在种群鉴定中的应用。ＲＡＰＤ引物筛选结果表明,所测试的２０个随机引物中（Ｔａｂｌｅ　１）,除一个引物未扩增出任何片段外,其余１９个引物均扩增出１～１１个大小不等的片段,长度大部分在５００～３０００ｂｐ之间,共扩增出２２０个片段,平均每个引物产生５．５个片段。两群体间共有片段７０条,大部分引物的扩增产物具有种间多态性,种群间相似系数为０．７２７。以筛选的引物对两种群不同个体（Ｆｉｇ．１,Ｔａｂｌｅ２）及种群混合样品（Ｆｉｇ．２,Ｔａｂｌｅ３）进行ＲＡＰＤ分析。结果表明,不同引物在扩增图谱上表现很大差异。奥利亚罗非鱼不同个体间表现为一致的扩增图谱,种内相似系数达１０００,显示了其种群内遗传变异的缺乏;尼罗罗非鱼种内相似系数为０．８２７,个体间存在不同程度的多态性;两个种群间的相似系数分别为０．７６７和０．７４２,表明种间有较高的同源性,遗传距离为０．２３５,略低于国外的报道、此外,两个养殖群体间的扩增图谱比较也暗示了遗传渐渗现象的存在。实验表明,ＲＡＰＤ标记可以作为一种可靠的遗传标记,用于不同鱼     

On the nature of P.P.L.O.

Summary In a number of strains of the three species of P.P.L.O. of human origin coccoid elements have been observed, which are Gram positive or Gram variable and of very small size (<0.5 μ). They are able to grow in pure culture on the surface of nutrient agar in very small colonies. Although they have bacterial characteristics, they could not be identified as known bacteria. Agglutination tests are in favour of a serological relationship between the coccoid elements and P.P.L.O. The suggestion that these elements might be an outside contamination is made unlikely by several observations. The supposition that P.P.L.O.s are L forms of these coccoid elements should be considered further.     

On the serological specificity of the Escherichia coli O8 and O9 antigens.

The O8 and O9-specific lipopolysaccharides of Escherichia coli lost their serological activity during liberation of the polysaccharide moieties (alpha-mannans) by mild acid hydrolysis, as tested by passive haemagglutination and haemagglutination inhibition. The serological activities and specificities were restored by substitution of the polysaccharides with 1 to 2 stearoyl groups per polysaccharide chain. The mannans obtained by biosynthesis in vitro were serologically active only when bound to the membrane-associated hydrophobic carrier molecule. Liberation of the polysaccharides from the carrier by treatment with aqueous phenol resulted in loss of the serological activity. The O8- and O9-specific mannans of E. coli are thus serologically active when they are part of an amphiphilic molecule and not as free polysaccharides.     

栽培稻×大颖野生稻F~2 多倍现象的细胞遗传学研究

A栽培稻(Oryza sativa)×大颖野生稻(Oryza grandiglumis)F2经细胞学鉴定为2n=4x=48, 即已由杂种F1的ACD异源三倍体变成了异源四倍体。研究了从粗线期到末期Ⅱ的染色体行为,结果表明,F2的染色体构型为异源节段异段类型,且异常染色体频率极高,合计为87.13%。各类异常染色体频率变化按比例大小依次为: 单价体,染色体拖曳,落后染色体,多价体,邻接型易位,不均等分离,桥,不分离和松散配对等。邻接型易位是本研究的中心论题。因邻接型易位的存在是F2花粉不育的一个重要原因, 也是产生节段异段染色体构型的重要原因;因邻接型易位带来相互易位,可供育种利用。 Abstract:The chromosome number in F2 of O.sativa×O.grandiglumis were 2n=4x=48.This showed that the allotriploid of hybrid F1 had been changed into allotetraploid in F2.The chromosome constitution of this allotetraploid remained to be determined.The chromosome behavior was studied during meiosis from pachytene to telophase II.Results showed that the chromosome configuration of F2 belonged to the type of the nodal section-allosection,and possessed very high rate of anomalous chromosome,the total rate of anomalous chromosome accounting for 87.13%.The frequency of anomalous chromosome were ranked as follows:univalent,chromosome straggling,lagging chromosome,polyvalent,adjoin translocation,unequal division,chromosome bridge,non-disjunction and loose pairing in descent order.The adjoin translocation was the topic in this study.With this translocation,no vitality gamentes were produced in F2.However,this is a mutual translocation,hence that is very useful for breeding.     

The B.T.O. in the Seventies

Since the cessation of grazing and the reduction of Rabbit activity the chalk downland at the eastern end of the Chiltern Hills has been invaded by scrub, mainly hawthorn, which has attracted a uniquely diverse breeding bird community. Census studies show how different species are adapting to the various phases of the secondary succession towards woodland climax, and some broad lines of management are indicated.     

C. O. Whitman and the American Society of Zoologists

C. O. Whitman (1842–1910) studied under Louis Agassiz,Anton Dohrn, and Rudolph Leuchart. Under the influence of E.S. Morse, Whitman served as the second professor of zoologyat the University of Tokyo (1880–81). For three yearshe was assistant to Alexander Agassiz at the Museum of ComparativeZoology. Between 1883 and 1886 Whitman was editor of the Departmentof Microscopy for the American Naturalist. He became the firstdirector of the Marine Biological Laboratory at Woods Hole,serving until 1908, and built that institution into an internationallyfamous center for education and research. He also became firstprofessor of Zoology at the University of Chicago where he remainedfor life. In 1887 he founded the Journal of Morphology, andlater Biological Lectures, and Zoological Bulletin which becamethe Biological Bulletin. His own research was in the fieldsof embryology, heredity, and evolution. In 1890 he, with colleagues,founded the American Morphological Society which became theAmerican Society of Zoologists over a period of 13 years (1901–13)by the union of regional groups. Whitman played a leading rolein the founding and early history of the Society.