Decreased acquisition of glucocorticoid resistance in tetraploid human lymphoid cells

Resistance to dexamethasone (1 microM) was measured in glucocorticoid-sensitive diploid and tetraploid clones of the human leukaemic cell line CCRF-CEM (clone C7) during continuous culture and after X-ray or chemical mutagenesis. In continuous culture resistant diploid cells accumulated at a rate of about one cell per 10(5) divisions, while the rate for tetraploid cells was less than one per 10(7) divisions. Chemical and X-ray mutagenesis caused a marked increase in the number of resistant diploid cells but had very little effect on tetraploid cells. These results are consistent with a mutational basis for the acquisition of the glucocorticoid-resistant phenotype in human lymphoid cells.     

盾叶薯蓣四倍体诱导的研究

目的 选育盾叶薯蓣Dioscoreazingiberensis新种质资源,以期为高产、高皂苷元含量薯蓣育种打下基础。方法 以刚露出绿色芽点的盾叶薯蓣愈伤组织块为材料,采用两种方法处理:①愈伤组织块浸泡到秋水仙素水溶液中。②培养基中添加秋水仙素。结果 成功获得了染色体数加倍的薯蓣新材料,其中以1×103mg/L秋水仙素水溶液浸泡24 h效果最好,诱导率达到35.2%,四倍体植株与二倍体亲本相比,二者在外观形态、生理指标、显微结构上有明显区别。结论 四倍体植株体型大、具生长优势,离体条件下利用愈伤组织块诱导多倍体是盾叶薯蓣倍性育种的一条有效途径。     

四倍体平贝母的诱导及鉴定

目的 运用组织培养技术诱导平贝母四倍体。方法 采用不同质量浓度（200、500、1 000、2 000 mg/L）秋水仙素和不同的诱导时间（12～72 h）处理平贝母愈伤组织。结果 离体培养条件下,平贝母激素自养型培养材料在秋水仙素诱导下得到四倍体,四倍体染色体4n＝44,四倍体植株出现明显的多倍体特征。结论 500 mg/L秋水仙素处理24 h为最佳组合,可以诱导四倍体平贝母以平贝母子球做鉴定材料,获得较好的结果。     

四倍体菘蓝体外抗内毒素、抗病毒作用评价

目的 :对四倍体菘蓝的药理作用进行评价。方法 :以同源二倍体亲本为对照 ,以鲎试剂法、鸡胚法分别考察四倍体菘蓝的抗内毒素、抗病毒作用。结果 :四倍体菘蓝的抗内毒素及抗病毒作用显著强于二倍体亲本 ,相同倍性菘蓝的叶的体外药理作用强于根。结论 :四倍体菘蓝是优质高效的新品系 ,具有很大的开发利用价值。     

转双价抗虫基因Bt-CpTI提高四倍体菘蓝对小菜蛾抗性

目的 将外源苏云金芽孢杆菌杀虫蛋白基因CrylA(c)和豇豆胰蛋白酶抑制剂基因CpTI共同转入四倍体菘蓝以获得鳞翅目昆虫小菜蛾抗性.方法 构建了以CaMV 35S为启动子,新霉素磷酸转移酶(Npt-Ⅱ)为选择标记,带有CrylA(c)基因和CpTI基因的植物表达载体pGBI121S4ABC并转入根癌农杆菌LBA4404.采用叶盘法遗传转化四倍体菘蓝.转基因再生植株经PCR和Southern杂交检测,并进行抗小菜蛾实验.结果 T0代转化四倍体菘蓝的双基因阳性转化率达到16.67%.Southern杂交检测结果表明外源CrylA(c)基因和CpTI基因均已经随机整合到转基因菘蓝的基因组中.与野生对照相比,转基因四倍体菘蓝对小菜蛾显示出明显抗性.结论 转双价抗虫基因Bt-CpTl是提高四倍体菘蓝对小菜蛾抗性的有效手段.     

A human tetraploid pachytene spermatocyte as the possible origin of diploid sperm: a case report

Diploid spermatozoa represent 0.2-0.3% of all spermatozoa in the normal population and cause 8.3% of diandric triploids. Errors in meiosis I and II are the most common mechanisms by which diploid spermatozoa are produced. Endoreduplication before meiosis has been suggested as a possible origin for tetraploid meiocytes, which might, in turn, produce diploid sperm. Synaptonemal complex (SC) spreads of a fertile man were immunolabelled (SCP3, MLH1 and CENP) and hybridized with subtelomere-specific multiplex fluorescent in situ hybridization (stM-FISH) assay for SCs identification. The unexpected finding of a tetraploid pachytene cell and the identification of all of its SCs demonstrate that synapsis and crossover events can occur in human tetraploid cells. Moreover, it indicates that diploid sperm may also originate from mitotic errors (endoreduplication) occurring before meiosis.     

不同倍性盾叶薯蓣的生理指标和薯蓣皂苷元量的比较研究

目的通过比较盾叶薯蓣Dioscoreazingiberensis人工四倍体植株和普通二倍体植株在抗性相关指标及薯蓣皂苷元量方面的差异,探索药用盾叶薯蓣倍性育种的应用前景。方法以秋水仙素诱导加倍的、经鉴定确认的3个不同株系四倍体盾叶薯蓣为材料,以二倍体原种为对照,采用分光光度法测定叶片超氧化物歧化酶(SOD)、过氧化物酶(PPO)活性以及可溶性糖的量;高锰酸钾滴定法测定过氧化氢酶(CAT)活性;采用HPLC法测定根状茎薯蓣皂苷元的量。结果四倍体植株SOD、PPO、CAT的活性以及可溶性糖的量明显高于二倍体;四倍体植株薯蓣皂苷元的量显著高于二倍体,增加幅度最大为二倍体原种的27%。结论人工四倍体植株薯蓣皂苷元量高,其生理指标也显示较强的抗性基础,可望直接利用或作为进一步培育高产、高薯蓣皂苷元量薯蓣新品种的良好育种材料。     

PEG介导高山红景天原生质体融合获同源四倍体研究

目的:获得高山红景天同源四倍体新材料。方法:用高山红景天愈伤组织原生质体为材料,进行了40%PEG6000介导的原生质体融合,对融合后原生质体进行了低密度、低融点琼脂包埋培养。按原生质体大小对融合原生质体进行了活体标记,建立了起源于单个原生质体的单细胞姊妹系,获得同源四倍体材料。结果:新生子细胞、中期细胞及其原生质体的直径RD与RM均与公式RD=0.793 7RM大致相符。未融合的二倍体、两原生质体融合产物直径的变化范围分别为16.7μm≤R21.3μm,21.0μm≤R′26.8μm,两者直径范围存在部分重叠。融合原生质体培养时,接种密度以1×104个/mL为宜,在此密度条件下植板率为20.3%,单细胞起源的姊妹系微克隆生长迅速,易于进行标记、彼此分离并继续培养;染色体计数的结果表明,二倍体、四倍体单细胞姊妹系再生植株染色体数目分别为26,52,不同节位叶片经流式细胞仪检测了DNA含量,证实没有嵌合体的存在。结论:本研究为高山红景天多倍体育种提供了科学依据。