Castignetti D, Siddiqui A S
Department of Biology, Loyola University of Chicago, IL 60626.
Biol Met. 1990;3(3-4):197-203. doi: 10.1007/BF01140579.
Three bacteria, two of which were previously noted as active heterotrophic nitrifiers, were examined for their ability to grow and nitrify with the siderophore deferrioxamine B as the carbon source. Pseudomonas aureofaciens displayed limited growth and nitrification while a heterotrophic nitrifying Alcaligenes sp. was without action concerning its metabolism of deferrioxamine B. The third bacterium, a unique Gram-negative soil isolate, was unable to nitrify deferrioxamine B but grew well when the siderophore was employed as the sole C source. The Gram-negative bacterium removed deferrioxamine B from the medium and left only residual amounts of the compound in solution at the termination of its growth. The organism was without action when the ferrated analogue of deferrioxamine B, ferrioxamine B, served as either the C source for growth, for metabolism by resting cells, or as the substrate for cell-free extracts. Deferrioxamine B, by contrast, was rapidly metabolized by resting cells. Cell-free extracts of the bacterium synthesized a monohydroxamate(s) when deferrioxamine B was the substrate. The catabolism of deferrioxamine B, which is synthesized by soil microbes, suggests that soil microflora have the ability to return deferrioxamine B, and perhaps other, siderophores to the C cycle.
对三种细菌进行了研究，其中两种细菌先前被认为是活跃的异养硝化菌，研究它们以铁载体去铁胺B作为碳源进行生长和硝化的能力。金黄色假单胞菌的生长和硝化作用有限，而异养硝化产碱菌属对去铁胺B的代谢没有反应。第三种细菌是一种独特的革兰氏阴性土壤分离菌，它不能硝化去铁胺B，但当以这种铁载体作为唯一碳源时生长良好。这种革兰氏阴性细菌从培养基中去除了去铁胺B，在其生长结束时，溶液中仅残留少量该化合物。当去铁胺B的铁化类似物铁胺B用作生长的碳源、静息细胞代谢的底物或无细胞提取物的底物时，该微生物没有反应。相比之下，去铁胺B能被静息细胞快速代谢。当以去铁胺B为底物时，该细菌的无细胞提取物合成了一种单异羟肟酸。由土壤微生物合成的去铁胺B的分解代谢表明，土壤微生物群落有能力使去铁胺B以及可能的其他铁载体回归到碳循环中。
