Brooks M H, Smith R L, Macalady D L
Water Resources Division, U.S. Geological Survey, Boulder, Colorado 80303-3328.
Appl Environ Microbiol. 1992 May;58(5):1746-53. doi: 10.1128/aem.58.5.1746-1753.1992.
Chloramphenicol completely inhibited the activity of existing denitrification enzymes in acetylene-block incubations with (i) sediments from a nitrate-contaminated aquifer and (ii) a continuous culture of denitrifying groundwater bacteria. Control flasks with no antibiotic produced significant amounts of nitrous oxide in the same time period. Amendment with chloramphenicol after nitrous oxide production had begun resulted in a significant decrease in the rate of nitrous oxide production. Chloramphenicol also decreased (greater than 50%) the activity of existing denitrification enzymes in pure cultures of Pseudomonas denitrificans that were harvested during log-phase growth and maintained for 2 weeks in a starvation medium lacking electron donor. Short-term time courses of nitrate consumption and nitrous oxide production in the presence of acetylene with P. denitrificans undergoing carbon starvation were performed under optimal conditions designed to mimic denitrification enzyme activity assays used with soils. Time courses were linear for both chloramphenicol and control flasks, and rate estimates for the two treatments were significantly different at the 95% confidence level. Complete or partial inhibition of existing enzyme activity is not consistent with the current understanding of the mode of action of chloramphenicol or current practice, in which the compound is frequently employed to inhibit de novo protein synthesis during the course of microbial activity assays. The results of this study demonstrate that chloramphenicol amendment can inhibit the activity of existing denitrification enzymes and suggest that caution is needed in the design and interpretation of denitrification activity assays in which chloramphenicol is used to prevent new protein synthesis.
氯霉素完全抑制了在乙炔阻断培养中现有反硝化酶的活性，培养对象为：（i）受硝酸盐污染含水层的沉积物，以及（ii）反硝化地下细菌的连续培养物。在同一时间段内，未添加抗生素的对照瓶产生了大量一氧化二氮。一氧化二氮产生开始后添加氯霉素，导致一氧化二氮产生速率显著下降。氯霉素还降低了（超过50%）在对数期生长时收获并在缺乏电子供体的饥饿培养基中维持2周的反硝化假单胞菌纯培养物中现有反硝化酶的活性。在旨在模拟用于土壤的反硝化酶活性测定的最佳条件下，对处于碳饥饿状态的反硝化假单胞菌在乙炔存在下的硝酸盐消耗和一氧化二氮产生进行了短期时间进程研究。氯霉素处理瓶和对照瓶的时间进程均呈线性，两种处理的速率估计在95%置信水平上有显著差异。对现有酶活性的完全或部分抑制与目前对氯霉素作用方式的理解或当前实践不一致，在当前实践中，该化合物经常用于在微生物活性测定过程中抑制从头蛋白质合成。本研究结果表明，添加氯霉素可抑制现有反硝化酶的活性，并表明在设计和解释使用氯霉素防止新蛋白质合成的反硝化活性测定时需要谨慎。
