假单胞菌的氯儿茶酚1,2-双加氧酶基因的克隆和表达

 从土壤中分离得到1株降解2,4-二氯酚(2,4-DCP)能力较强的细菌菌株GT241-1,克隆了该菌株的3,5-二氯儿茶酚1,2-双加氧酶基因(dcpB),采用的克隆策略为:用Southern杂交对dcpB进行定位后,构建重组质粒,再用斑点杂交从重组质粒中筛选目的转化子.经序列测定得知dcpB亚克隆片段全长4303bp,其中dcpB基因编码区765bp.核苷酸和推测的氨基酸序列分析表明,dcpB与已在GenBank登记的相关基因有一定的差异.dcpB基因能够在大肠杆菌转化子中成功地表达有生物活性的酶.     

Experimental study on Cr(Ⅵ) reduction by Pseudomonas aeruginosa

Investigation on Cr( Ⅵ ) reduction was conducted using Pseudomonas aeruginosa. The study demonstrated that the Cr(Ⅵ) canbe effectively reduced to Cr( Ⅲ ) by Pseudomonas aeruginosa. The effects of the factors affecting Cr( Ⅵ ) reduction rate including carbon source type, pH, initial Cr(Ⅵ) concentration and amount of calls inoculum were thoroughly studied. Malate was found to yield maximum biotransformation, followed by succinate and glucose, with the reduction rate of 60.86%, 43. 76% and 28.86% respectively. The optimum pH for Cr( Ⅵ ) reduction was ?.0, with reduction efficiency of 61.71 % being achieved. With the increase of initial Cr(Ⅵ) concentration,the rate of Cr(Ⅵ) reduction decreased. The reduction was inhibited strongly when the initial Cr(Ⅵ) concentration increased to 157 mg/L. As the amount of cells inoculum increased, the rate of Cr( Ⅵ ) reduction also increased. The mechanism of Cr( Ⅵ ) reduction and final products were also analysed. The results suggested that the soluble enzymes appear to be responsible for Cr (Ⅵ) reduction by Pseudomonas aeruginosa, and the reduced Cr( Ⅲ ) was not precipitated in the form of Cr(OH)3.     

内电解法处理染料废水的研究进展

综述了内电解法处理染料废水的现状，对该方法的作用机理、应用实例、工艺改进方面的研究进行了介绍，并分析了该方法的优缺点及其今后的发展方向。     

内电解组合工艺处理重度富营养化水体的初步中试试验

采用催化铁内电解-沸石床-生物活性炭组合工艺进行了处理重度富营养化水的中试试验.通过对进水与出水浊度、TP、CODMn、UV254、总铁、NH3-N、和NO2--N的监测,研究了本组合工艺对重度富营养化水体的处理性能.试验期间,水温约在10℃.初步结果表明,本组合工艺对浊度、TP、CODMn和UV254均有较好的去除作用,平均去除率达到50%以上,出水中铁含量均低于进水.由于水温过低,未观察到氨氮和亚硝酸盐氮的明显变化.     

Intra-specific variations of two Leymus chinensis divergence populations in Songnen Plain, northeast China

Population demography, seed production, biomassallocation, net photosynthesis and transpiration of two Leymus chinensis divergence populations and between two years in Songnenplain, northeast China were compared. Strong differences betweenthe dry 1997 and moist 1998 occurred in vegetative shoot and sexualshoot densities, sexual differentiation and tiller densities, aswell as in the lengths of inflorescence, seed numbers perinflorescence, seed weights and biomass allocation in eachpopulation respectively (P<0.01). While strong differences betweenthe two populations occurred in vegetative shoot densities, sexualshoot densities, sexual differentiation and seed weights in eachyear (P<0.01). The differences between the two populations intiller densities and in biomass allocation to sexual shoots were significant (P<0.05). But there were no significant differences between the two populations in the lengths of inflorescence, seed numbers per inflorescence and biomass allocation to rhizomes and vegetative shoots (P>0.05). Excepting the transpiration rate in the early June, the differences between the two populations in net photosynthesis and transpiration rate of vegetative shoots and sexual shoots were strongly significant in the early June and July respectively (P<0.01). Relative stable variations in population demography and physiological traits between the two populations indicated that they are divergently in the Songnen Plain.     

广东COD削减:水环境整治成效明显

广东境内河涌密布,对于环保部门而言,确保水环境安全是一件关系民生的大事.随着珠三角经济的高速发展,广东省环境压力持续增大,水环境状况同样不容乐观.     

伊朗化学品列车发生爆炸酿惨祸

2004年2月18日,伊朗一列满载多种化学材料的货车在伊东北部脱轨,起火后并发生一连串爆炸,导致发生200余人丧生、350余人受伤的惨剧。据伊朗官方通讯社消息,共有5个村庄在爆炸中遭到严重损坏。 该列货车共有51节车厢,当时正停靠在内沙布尔市附近的阿布穆斯林这个小站,车上满载硫磺、燃油以及其他化学工业品。由于列车车厢在没有引擎牵引的情况下突然移动,而且没有列车员控制其方向,当列车滑行到卡亚姆车站时,终于翻车脱轨,并引发熊熊大火。     

主次波长新分光光度法测定天然水硝酸盐

在硫酸介质中,邻苯氨基苯甲酸与硝酸盐(NO_3~-)生成紫红色络合物.本文依据悬浮颗粒对光的吸收性质研究利用该灵敏反应测定 NO_3~—N 新光度法——(?)次双波长法,通过对样品分析,可提高分析灵敏度和精密度,回收良好,且操作简单快速,计算曲线稳定,适合于测定地下水,湖水等天然水体 NO_3~-—N.     

固定化荧光假单胞菌降解阴离子表面活性剂的研究

用海藻酸钠法包埋适冷性微生物荧光假单胞菌株AIS-11,并用于处理阴离子表面活性剂废水,所有实验均在批式反应器中进行。以L_9(3~4)正交试验确定了其对阴离子表面活性剂十二烷基硫酸钠(SDS)和十二烷基苯磺酸钠(SDBS)的最佳包埋条件,并且对游离细胞和固定化菌体的降解过程进行了动力学分析和比较。结果表明,固定化珠体能将吸附和生物催化过程有机地耦联起来,有效地提高了阴离子表面活性剂的降解速率,将底物最大利用速度(mg/L·h)从游离细胞的5.75(SDS)和5.12(SDBS)分别提高至22.89和25.14。     

酚二磺酸光度法测硝酸盐氮水样预处理方法的改进

酚二磺酸光度法是测定水中硝酸盐氮的首选方法。但水样预处理方法麻烦，且掌握不好易使实验失败。术中介绍了对水样的预处理方法所进行的改进，通过改进得到了较好的效果。