DeWeerd K A, Concannon F, Suflita J M
Department of Botany and Microbiology, University of Oklahoma, Norman 73019.
Appl Environ Microbiol. 1991 Jul;57(7):1929-34. doi: 10.1128/aem.57.7.1929-1934.1991.
Resting-cell suspensions of Desulfomonile tiedjei consumed H2 with 3-chloro-, 3-bromo-, and 3-iodobenzoate as electron acceptors with rates of 0.50, 0.44, and 0.04 mumol h-1 mg-1, respectively. However, benzoate and 3-fluorobenzoate were not metabolized by this bacterium. In addition, H2 uptake was at least fourfold faster when sulfate, sulfite, or thiosulfate was available as the electron acceptor instead of a haloaromatic substrate. When sulfite and 3-chlorobenzoate were both available for this purpose, the rate of H2 uptake by D. tiedjei was intermediate between that obtained with either electron acceptor alone. Hydrogen concentrations were reduced to comparably low levels when either 3-chlorobenzoate, sulfate, or sulfite was available as an electron acceptor, but significantly less H2 depletion was evident with benzoate or nitrate. Rates of 3-chlorobenzoate dechlorination increased from an endogenous rate of 14.5 to 17.1, 74.0, 81.1, and 82.3 nmol h-1 mg-1 with acetate, pyruvate, H2, and formate, respectively, as the electron donors. Sulfite and thiosulfate inhibited dehalogenation, but sulfate and NaCl had no effect. Dehalogenation and H2 metabolism were also inhibited by acetylene, molybdate, selenate, and metronidazole. Sulfite reduction and dehalogenation were inhibited by the same respiratory inhibitors. These results suggest that the reduction of sulfite and dehalogenation may share part of the same electron transport chain. The kinetics of H2 consumption and the direct inhibition of dehalogenation by sulfite and thiosulfate in D. tiedjei cells clearly indicate that the reduction of sulfur oxyanions is favored over aryl dehalogenation for the removal of reducing equivalents under anaerobic conditions.(ABSTRACT TRUNCATED AT 250 WORDS)
蒂氏脱硫单胞菌的静息细胞悬浮液以3-氯苯甲酸、3-溴苯甲酸和3-碘苯甲酸作为电子受体消耗氢气，速率分别为0.50、0.44和0.04 μmol h⁻¹ mg⁻¹。然而，该细菌不能代谢苯甲酸和3-氟苯甲酸。此外，当硫酸盐、亚硫酸盐或硫代硫酸盐作为电子受体而非卤代芳烃底物时，氢气摄取速度至少快四倍。当亚硫酸盐和3-氯苯甲酸都可用于此目的时，蒂氏脱硫单胞菌摄取氢气的速率介于单独使用任一电子受体时的速率之间。当3-氯苯甲酸、硫酸盐或亚硫酸盐作为电子受体时，氢气浓度降低到相当低的水平，但以苯甲酸或硝酸盐作为电子受体时，氢气消耗明显较少。以乙酸盐、丙酮酸盐、氢气和甲酸盐分别作为电子供体时，3-氯苯甲酸的脱氯速率从内源性速率14.5增加到17.1、74.0、81.1和82.3 nmol h⁻¹ mg⁻¹。亚硫酸盐和硫代硫酸盐抑制脱卤作用，但硫酸盐和氯化钠没有影响。乙炔、钼酸盐、硒酸盐和甲硝唑也抑制脱卤作用和氢气代谢。亚硫酸盐还原和脱卤作用受到相同呼吸抑制剂的抑制。这些结果表明，亚硫酸盐还原和脱卤作用可能共享部分相同的电子传递链。蒂氏脱硫单胞菌细胞中氢气消耗的动力学以及亚硫酸盐和硫代硫酸盐对脱卤作用的直接抑制清楚地表明，在厌氧条件下，硫氧阴离子的还原比芳基脱卤作用更有利于去除还原当量。（摘要截断于250字）
