Westfall H N, Rollins D M, Weiss E
Appl Environ Microbiol. 1986 Oct;52(4):700-5. doi: 10.1128/aem.52.4.700-705.1986.
An attempt was made to elucidate in Campylobacter spp. some of the physiologic characteristics that are reflected in the kinetics of CO2 formation from four 14C-labeled substrates. Campylobacter jejuni and C. coli were grown in a biphasic medium, and highly motile spiral cells were harvested at 12 h. Of the media evaluated for use in the metabolic tests, minimal essential medium without glutamine, diluted with an equal volume of potassium sodium phosphate buffer (pH 7.2), provided the greatest stability and least competition with the substrates to be tested. The cells were incubated with 0.02 M glutamate, glutamine, alpha-ketoglutarate, or formate, or with concentrations of these substrates ranging from 0.0032 to 0.125 M. All four substrates were metabolized very rapidly by both species. A feature of many of these reactions, particularly obvious with alpha-ketoglutarate, was an immediate burst of CO2 production followed by CO2 evolution at a more moderate rate. These diphasic kinetics of substrate utilization were not seen in comparable experiments with Escherichia coli grown and tested under identical conditions. With C. jejuni, CO2 production from formate proceeded rapidly for the entire period of incubation. The rate of metabolism of glutamate, glutamine, and alpha-ketoglutarate by both species was greatly enhanced by increased substrate concentration. The approach to the study of the metabolism of campylobacters here described may be useful in detecting subtle changes in the physiology of cells as they are maintained past their logarithmic growth phase.
本研究旨在阐明弯曲杆菌属细菌的一些生理特性，这些特性可从四种14C标记底物生成二氧化碳的动力学中反映出来。空肠弯曲杆菌和大肠弯曲杆菌在双相培养基中培养，12小时后收获高度运动的螺旋状细胞。在评估用于代谢试验的培养基中，不含谷氨酰胺的最低必需培养基，用等体积的磷酸钾钠缓冲液（pH 7.2）稀释，提供了最大的稳定性，并且与待测试底物的竞争最小。将细胞与0.02 M的谷氨酸、谷氨酰胺、α-酮戊二酸或甲酸，或与浓度范围为0.0032至0.125 M的这些底物一起孵育。两种细菌都能非常迅速地代谢所有四种底物。许多这些反应的一个特点，在α-酮戊二酸反应中尤为明显，是二氧化碳的立即爆发性产生，随后以更适中的速率释放二氧化碳。在相同条件下生长和测试的大肠杆菌的可比实验中，未观察到这些底物利用的双相动力学。对于空肠弯曲杆菌，在整个孵育期间，甲酸产生二氧化碳的过程都很快。两种细菌对谷氨酸、谷氨酰胺和α-酮戊二酸的代谢速率都因底物浓度的增加而大大提高。这里描述的弯曲杆菌代谢研究方法，可能有助于检测细胞在超过对数生长期后维持时生理上的细微变化。
