Fava F, Di Gioia D, Romagnoli C, Marchetti L, Mares D
Department of Applied Chemistry and Material Science, Engineering Faculty, University of Bologna, Italy.
Arch Microbiol. 1993;160(5):350-7. doi: 10.1007/BF00252220.
A strain of Pseudomonas fluorescens was capable of co-metabolizing 3-chlorobenzoic acid with the production of a chlorinated catechol black pigment. A peroxidase and another enzymatic activity referred to as a polyphenol oxidase were found to be involved in the oxidation of 4-chlorocatechol to 4-chloro-1,2-benzoquinone, i.e. in the production of highly reactive substrates for pigment formation. Therefore, P. fluorescens cells were seen to take an active part not only in 3-chlorobenzoate mineralization but also in overall pigment production. pH was found to be a key parameter in the regulation of the activity of P. fluorescens oxidoreductive enzymes. Ultrastructural investigations showed that electron dense granules of pigment were distributed throughout the cytoplasm of Pseudomonas fluorescens cells grown in presence of 3-chlorobenzoate, as confirmed also by Thiéry cytochemical investigations. In these cells, an extensive contraction of the cytoplasm as well as a significant damage to the cell wall after two days of incubation, suggested that pigment production caused a premature death of the cells accompanied by the leakage of the cell content. Pigment production seemed to occur mostly in the cytoplasmic context where the electron dense material accumulates until it is released in the medium after the cell lysis.
一种荧光假单胞菌菌株能够共代谢3-氯苯甲酸，并产生一种含氯儿茶酚黑色色素。发现一种过氧化物酶和另一种被称为多酚氧化酶的酶活性参与了4-氯儿茶酚氧化为4-氯-1,2-苯醌的过程，即参与了形成色素的高活性底物的产生。因此，荧光假单胞菌细胞不仅在3-氯苯甲酸矿化中发挥积极作用，而且在整个色素产生过程中也发挥积极作用。发现pH是调节荧光假单胞菌氧化还原酶活性的关键参数。超微结构研究表明，在3-氯苯甲酸存在下生长的荧光假单胞菌细胞的细胞质中分布着电子致密的色素颗粒，蒂埃里细胞化学研究也证实了这一点。在这些细胞中，孵育两天后细胞质广泛收缩以及细胞壁受到严重损伤，这表明色素产生导致细胞过早死亡并伴有细胞内容物泄漏。色素产生似乎主要发生在细胞质环境中，电子致密物质在其中积累，直到细胞裂解后释放到培养基中。
