• 关键词：球形红细菌  铅  转化机理  半胱氨酸脱巯基酶

• 基金项目：国家科技攻关计划项目(No2001BA540C)

• 白红娟
• 1. 山西大学生命科学与技术学院, 太原030006; 2. 中北大学化工与环境学院, 太原030051

• 张肇铭
• 山西大学生命科学与技术学院, 太原030006

• 贠妮
• 中北大学化工与环境学院, 太原030051

• 王玉芬
• 东北大学环境与土木工程学院, 沈阳110004

• 杨官娥
• 山西大学生命科学与技术学院, 太原030006

• 摘要：通过X-射线衍射光谱分析,球形红细菌(Rhodobacter sphaeroides)H菌株对铅离子的转化产物为硫化铅.H菌株在不同浓度Pb²⁺中培养后,研究了该菌株生长细胞对Pb²⁺去除的动力学和该菌体产生半胱氨酸脱巯基酶活性的变化,用聚丙烯酰胺凝胶电泳法分析了其同工酶谱.结果表明,Pb²⁺浓度为25～150mg·L^-1时,去除速率常数k较大,半衰期T1/2较短,去除率较高;Pb²⁺浓度为75、100和150mg·L^-1时,对H菌株产生半胱氨酸脱巯基酶活力有明显的促进作用,Pb²⁺浓度为200mg·L^-1时,对该酶活力有抑制作用.该菌体细胞及亚细胞组分中铅含量测定结果显示,94%的Pb²⁺分布于细胞壁和细胞质内,仅少量存在于细胞膜上,并结合透射电镜观察和红外光谱分析,证明了该H菌株对铅离子去除和转化是在细胞质内进行的.

• Abstract：The product which Pb²⁺ was transformed into by Rhodobacter sphaeroides Hstrain proves to be lead sulfides through X-ray diffraction diagram analysis. After Hstrain was cultivated in medium containing different concentrations of Pb²⁺, the removal kinetics by Hstain growth cells and the change of activity of cysteine desulfhydrase of Hstrain producing were studied, and the pattern of isoenzymes of the kind of enzyme was further analyzed using PAGEmethods. The results demonstrated that the removal rate constants (k) were high, half lives (T1/2) were short and the removal efficiencies were great in the presence of 25～150 mg·L^-1 of Pb²⁺. The activities of cysteine desulfhydrase of Hstrain producing were obviously stimulated in the presence of 75,100 and 150 mg·L^-1 of Pb²⁺, respectively, whereas the activity of the kind of enzyme was inhibited in the presence of 200 mg·L^-1 of Pb²⁺. The measure of cellular subfractions showed that cell wall and cytoplasm fraction concentrated 94% of the lead taken up by cells, but cell membrane only concentrated a few of the lead. The analysis of TEMand IRspectrum indicated that the removal and transformation of Pb²⁺ by Hstrain were completed inside cytoplasm.

• Key words：Rhodobacter sphaeroides  lead  transformation mechanism  cysteine desulfhydrase

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