小麦单细胞培养的研究——再生植株后代花粉母细胞染色体行为与花粉粒育性

在单细胞培养再生植株后代农艺性状和产量性状研究基础上 ,进一步对再生植株后代的花粉母细胞染色体行为和花粉粒育性进行研究。结果表明 ,花粉母细胞染色体行为发生异常 ,出现落后染色体、环形染色体、染色体桥、断片和粘连以及花粉母细胞仅发生核裂、三极纺锤体、多分体等 ,其中多以落后染色体花粉母细胞出现的频率为最高 ,早期世代为 8.0 3 %～ 51.11% ,随着繁殖世代的增加 ,这种异常的比率逐渐降低 ,到高世代 ( SCC6代 )仅为 0 .50 %～ 9.80 %。花粉粒育性分析结果表明 ,尽管早期世代花粉母细胞发生异常的比率较大 ,但各株系的可育花粉粒比例都在 60 %以上 ,并且均表现为正常结实 ,未发现不育现象。随着世代增加 ,育性也在不断改善 ,高世代绝大多数株系可育花粉粒的比例都在 98%以上。再生植株花粉粒的育性与花粉母细胞染色体变化密切有关     

Optomotor response in human infants to apparent motion: evidence of innateness

Human infants were placed inside a stationary cylinder containing a columnar pattern like that used to elicit the optokinetic reflex. By sequential illumnination of the columns, the pattern was made to appear to rotate. Optokinetic nystagmus was clearly evoked in 64.7 percent of the subjects, with a weak-positive response in an additional 11.8 percent.     

莲多倍体研究：Ⅱ.莲花粉母细胞减数分裂行为观察

为了给莲的多倍体育种提供细胞学依据,以寸三莲及其变异株为材料,采用涂抹制片法研究莲花粉母细胞减数分裂行为,观察结果表明：二倍体莲花粉母细胞减数分裂形成四分体的方式属连续型,四分体两侧对称．经秋水仙素处理后莲的花粉母细胞在减数分裂过程中染色体数目发生改变,减数分裂行为发生异常,如见环状染色体、染色体落后、减数分裂不同步及双核仁等现象．     

灌溉区工业废水对大蒜根尖细胞的毒性研究

用流经灌溉区的张掖地区造纸厂、化肥厂两厂不同采集点的废水处理大蒜根尖24h后,根尖细胞有丝分裂指数下降,异常细胞数目明显增多,间期细胞主要表现为核突出物、微核、核解体等;分裂期细胞主要表现为C-有丝分裂、多极分裂、染色体桥、染色体断裂、滞后染色体、染色体粘连等畸变类型。     

多普勒超声脐动脉血流图在产前监测中的应用

目的 :评价脐动脉超声血流图在产前监测中的作用。方法 :孕妇 2 6 0例 (孕 37～ 42周 )用多普勒超声行脐动脉血流图检查并计算 S/ D值 ,胎心无负荷试验 (NST) ,检查结果与分娩后新生儿出生体重、羊水污染、脐带绕颈或过短、新生儿窒息等进行比较。结果 :S/ D值异常组 6 9例 ,其中分娩低体重儿 8例 (11.6 % )、发生羊水污染 30例 (4 3.5 % )、脐带缠绕或过短 2 0例 (9.0 % )、新生儿窒息 12例 (17.4% ) ,均较 S/ D值正常组明显增高 (P<0 .0 1)。结论 :超声脐动脉血流图在判断宫内胎儿变化中起着重要作用 ,与 NST联合应用对围产儿预后能作出早期诊断 ,能提高围产期保健质量。     

大豆光敏雄性不育株88-428BY-827小孢子母细胞的细胞学观察

 以长光照条件下的大豆光敏雄性不育88-428BY的雄性可育株为对照,对其短光照条件下的雄性不育株进行了小孢子母细胞减数分裂的观察。结果表明,88-428BY-827雄性不育株花粉败育在发育各个时期都发生。88-428BY-827雄性不育株小孢子母细胞减数分裂的染色体的行为出现了多种类型的异常现象:联会异常、单价体、三价体、染色体落后、染色体粘连、染色体桥、染色体不均等分离等;单核小孢子阶段小孢子饱满、细胞核内染色体明显且超出正常的染色体数目;少数小孢子的萌发孔为4个;成熟的花粉粒大小不等、形状不规则、甚至形     

Meiotic recombination in yeast: alteration by multiple heterozygosities

Although meiotic gene conversion has long been known to be accompanied by crossing-over, a direct test of the converse has not been possible. An experiment was designed to determine whether crossing-over is accompanied by gene conversion in Saccharomyces cerevisiae. Nine restriction site heterologies were introduced into a 9-kilobase chromosomal interval that exhibits 22 percent crossing-over. Of all the exchange events that occurred, at least 59 percent of meiotic crossovers are accompanied by gene conversion of one or more of the restriction site heterologies. The average gene conversion tract length was 1.5 kilobases. An unexpected result was that the introduction of as few as seven heterozygosities significantly altered the outcome of recombination events, reducing the frequency of crossovers by 50 percent and increasing the number of exceptional tetrads. This alteration results from a second recombination event induced by repair of heteroduplex DNA containing multiple mismatched base pairs.     

Mapping of the human Blym-1 transforming gene activated in Burkitt lymphomas to chromosome 1

Blym-1, a transforming gene detected by transfection of NIH 3T3 cells with DNA from Burkitt lymphomas, was mapped to the short arm of chromosome 1 (1p32) by chromosomal in situ hybridization. The Blym-1 gene was not physically linked to the cellular myc oncogene or to any of the immunoglobulin gene loci implicated in the characteristic chromosomal translocations in Burkitt lymphoma.     

Human von Willebrand factor (vWF): isolation of complementary DNA (cDNA) clones and chromosomal localization

Human factor VIII--von Willebrand factor (vWF) is a large, multimeric glycoprotein that plays a central role in the blood coagulation system, serving both as a carrier for factor VIIIC (antihemophilic factor) and as a major mediator of platelet-vessel wall interaction. Diminished or abnormal vWF activity results in von Willebrand's disease (vWD), a common and complex hereditary bleeding disorder. Overlapping vWF cDNA clones that span 8.2 kilobases of the vWF messenger RNA have been obtained. vWF accounts for approximately 0.3 percent of endothelial cell messenger RNA and was undetectable in several other tissues examined. A large single copy gene for vWF is located on the short arm of chromosome 12 (12p12----12pter). No gross gene rearrangement or deletion was detected in the DNA of two patients with severe vWD.     

Analysis of the Abnormal Segregation of Pathogenicity in Magnaporthe grisea by Using a Genetic Cross of Oryza and Eleusine Isolates

A genetic cross between Oryza isolate Y93-164a-1 and Eleusine isolate SA98-4 was established, and the pathogenicity of 151 F1 progeny isolates was investigated on both host plants rice and finger millet. Results showed that the segregation of pathogenicity in this genetic cross was abnormal, i.e., most of the progeny isolates were nonpathogenic on both host plants. However, no abnormal segregation was observed when middle repetitive sequence MGR586 and 31 single-copy RFLP markers from all of the chromosomes were genetically analyzed. At the same time, comparison of the chromosomal organization among two pairs of parental isolates did not find any genomic abnormity. These results suggested that the ＂abnormal＂ inheritance of pathogenicity in this cross was most likely due to the reassortment of numerous host species specificity genes but not the biased segregation of the host species specificity genes. The host species specificities in M. grisea were likely to be multigenically controlled, at least in the genetic cross involving rice pathogen and the grasses pathogen other than rice.     

武汉市南湖区域不同污染水源对蚕豆根尖细胞有丝分裂期染色体的影响

对蚕豆根尖组织进行了南湖区域医疗废水、工业废水,实验废水及生活污水等多种不同来源的典型污染水样暴露试验,通过常规染色压片技术对蚕豆根尖细胞的有丝分裂过程进行检测,探查南湖区域不同污染水体对蚕豆根尖细胞有丝分裂期染色体的影响。结果表明:不同污染程度的废水均能使细胞的生长受到明显的抑制,对染色体产生不同程度的影响;同时细胞还出现微核、异常染色体产生不均衡的多极移动分布、染色体片段、染色体桥及环状染色体等异常现象。     

Herpes-type virus and chromosome marker in normal leukocytes after growth with irradiated Burkitt cells

Cultured cells derived from male patients with Burkitt's lymphoma and harboring herpes-type virus particles were lethally irradiated. These irradiated cells induced normal peripheral leukocytes of female infants to grow within 2 to 4 weeks after mixed cultivation. Cells of a line free of this agent failed to stimulate growth. If either type of cell was cultured separately, it did not survive under the experimental conditions. Herpes-type viral antigen and C-group chromosomal marker previously described in cultured Burkitt cells were found in all of the female cell cultures that were obtained.     

华山松感染茶藨生柱锈菌后挥发性成分的变化

对华山松健康树皮、感病树皮、锈孢子3种材料挥发性成分GC/MS进行了比较分析.在健康树皮中苯和柠檬烯的相对质量分数分别为16.45%、27%,而这2种物质在感病树皮中均未检测出来;感病树皮中5,5-二甲基-3-异丙基环戊烯的质量分数为19.44%,而在健康树皮和锈孢子中均未检测出来;锈孢子挥发油的主要成分分别是2, 6, 6-三甲基双环[3.1.1]-2-庚烯(6.32%)、柠檬烯(6.04%)和对二甲苯(5.93%)等.     

巴东醉鱼草不同方法提取物的杀虫活性

为探讨巴东醉鱼草(Buddleja albiflora Hemsl.)的杀虫活性物质,以3龄粘虫(Mythimna separatea W.)为试虫,采用冷浸法、加热回流法、超声波法和渗漉法得到的巴东醉鱼草提取物应用小叶碟添加法进行毒力测定.结果表明:不同提取方法对茎的提取率均最低,叶的提取率最高.其中加热回流法对茎、叶、花的提取率最高,分别为5.76%、10.32%和9.29%,其次为超声波法,冷浸法最低.在浓度较大时,提取物对试虫的拒食活性较高;在浓度为相当于干样10 mg/mL时提取物对粘虫的生长发育影响较大,使试虫蜕皮不正常、最终出现畸形蛹或者是羽化不正常,其中加热回流法和超声波法的提取物效果明显.其中,叶的加热回流法提取物使试虫的56.67%由于生长发育不正常导致死亡;叶的超声波法提取物次之,为40%.     

Lysergic acid diethylamide: effect on embryos

Injection of lysergic acid diethylamide tartrate into mice in early pregnancy caused a 57 percent incidence of grossly abnormal embryos.     

Inv(13)(p12 q14)一家系报道

先证者女汉族24岁,身高1.61米.体重60.1公斤。因连续生两胎畸形儿夭折就诊。第一胎为足月顺产,唇裂、腭裂.双脚各为6趾,50天时因呼吸道感染而死亡。第二胎.足月顺产,体征似第一胎,生下两天死亡。外周血染色体检查,分别计数50个细胞,G 显带分析20个核型均为46,xx.Inv(13)(p12 q14)臂间倒位.患者父亲及其兄长核型与患者相同。其丈夫体征与核型均正常。其姐、妹及母亲因居住内地未查,患者哥及姐所生子女表形均无异常。     

利用近等基因系验证水稻细菌性条斑病抗性QTL

以均匀分布于水稻12条染色体上的104个SSR标记,通过图示基因型分析法对抗水稻细菌性条斑病的近等基因系H359R的基因组组成进行分析,并结合初步定位的遗传图谱、水稻物理图谱以及水稻SSR遗传图谱的线性比较结果,对H359R携有的细条病抗性QTL进行分析.结果表明,抗病近等基因系H359R包含3个来自抗病亲本Acc8558的抗性QTL区段,1个来自感病亲本H359的抗性QTL区段,证实了之前对细条病抗性QTL初步定位的可靠性.同时该结果也显示,只要聚合4-5个主要QTL的抗病等位基因,即能培育出高抗细条病的品种.     

5-methylcytidylic acid: absence from mitochondrial DNA of frogs and HeLa cells

The content of 5-methylcytidylic acid in nuclear DNA and mito chondrial DNA of Xenopus laevis and HeLa cells has been determined. Both nuclear DNA's contain 5-methylcytidylic acid. The 5-methylcytidylic acid content of X. laevis DNA is 1.7 mole percent of total nucleotides, and that of HeLc cell DNA is 0.7 mole percent. In neither mitochondrial DNA could any 5-methylcytidylic acid be detected; the limit of sensitivity was judged at below 0.1 mole percent for X. laevis DNA and below 0.05 mole percent for HeLa cell DNA.     

节瓜品种耐热性鉴定指标的研究

对节瓜品种耐热性鉴定指标的研究结果表明 :节瓜营养生长阶段与生殖生长阶段表现的耐热性不尽相同 ,商品产量是衡量节瓜耐热性的最重要指标 ,与商品产量呈显著相关的因子如病毒病病情指数、苗期电导率等可作为节瓜耐热性指标 ,而座果率、畸形瓜率及疫病发病率等性状只能作为节瓜耐热性的辅助指标。