A novel salicylaldehyde dehydrogenase-NahV involved in catabolism of naphthalene from Pseudomonas putida ND6

A novel salicylaldehyde dehydrogenase involved in catabolism of naphthalene from Pseudomonas putida ND6, NahV, has been identified. NahV exhibited lower identity in amino acid sequence with the classic salicylaldehyde dehydrogenase, NahF, from P. putida ND6. This is the first report of an isofunctional enzyme of bacterial salicylaldehyde dehydrogenase. Comparison of Km and Vmax values of NahV and NahF demonstrated that NahF has a more efficient catalytic reaction than NahV, while NahV has much higher affinity for salicylaldehyde and NAD . Both enzymes exhibited broad substrate speci- ficities and catalyzed the oxidation of salicylaldehyde, 5-chlorosalicylaldehyde, formaldehyde, m-nitrobenzaldehyde, o-nitrobenzaldehyde, o-methoxybenxaldehyde, glutaraldehyde, caprylic aldehyde, and glyoxal. However, the relative rates at which the substituted analogs are transformed differ considerably. NahV activity could be enhanced by Fe2 , Cu2 and Zn2 ; whereas NahF activity could only be stimulated by Fe2 . NahF is more stable than NahV at elevated temperatures. Dot-blot hybridization analyses showed that nahF-like genes occurred in all naphthalene-degradation bacteria isolated in this study, whereas nahV-like genes were present in only some naphthalene-degrading bacteria.     

大刍草血缘普通玉米自交系的配合力分析

以6个含有一年生墨西哥大刍草血缘的自交系为被测系,采用NCⅡ遗传交配设计对6个含大刍草血缘的玉米自交系的配合力进行研究。结果表明：亲本98—3／／（200B／大刍草）／／／98—3的单株产量GCA较高;单株产量SCA效应值最大的组合是绵714×M4,具有一定利用潜力;根据SCA效应及产量表现,将6个远缘杂交选系初步划分为4个不同类群。利用一年生墨西哥大刍草来改良普通栽培玉米自交系是可行的,但选到理想自交系的可能性较小。     

铝诱导普通野生稻(Oryza rufipogon L.)光合系统相关基因表达

采用抑制差减杂交技术对正常与铝毒处理的普通野生稻植株进行表达基因差异性分析，通过对差异表达基因的PCR选择性研究，阳性表达基因的测序、Northern杂交的进一步分析，得出3个cDNAs在铝毒处理的叶片中高效表达，其中2个与光合系统代谢相关，1个与花的发育有关，研究结果为更好地理解植物在铝毒胁迫下叶片相关基因表达提供思路，同时也为在野生稻这个丰富基因库中筛选出耐铝毒的重要基因，以便改良亲源较近的水稻适应日益酸化的土壤具有一定的意义。     

Al－Co合金富Co区相图计算与性质

应用经验电子理论和集团变分方法计算了Ａｌ－Ｃｏ合金富Ｃｏ区的相图。研究了无序－有序相的原子状态和相互作用的变化。     

岳鲤及其双亲(荷包红鲤♀、湘江野鲤♂)的生物学研究 Ⅱ.岳鲤及其双亲的酯酶同工酶分析

用聚丙烯酰胺凝胶盘状电泳分析了荷包红鲤、湘江野鲤和其杂交一代血清、肌肉、肝脏和肾脏4种组织的酯酶同工酶谱。实验结果表明:荷包红鲤和湘江野鲤虽隶属同一个种的不同生态群,但其对应组织的酯酶同工酶谱差异明显;杂交F_1代的血清和肌肉组织表现了亲本双方的酯酶同工酶,但肝脏和肾脏的酯酶分别与父、母本相似。由此可见,酯酶同工酶是鲤鱼种内杂交育种中,亲本及后代鉴定的有效标志。同时,根据亲本和后代的酯酶同工酶谱,可以解释杂交一代某些杂种优势现象。