Department of Microbiology, Macdonald College of McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X ICO.
Appl Environ Microbiol. 1987 Jul;53(7):1487-95. doi: 10.1128/aem.53.7.1487-1495.1987.
The rates of uptake by Alteromonas haloplanktis of 19 metabolizable compounds and by V. fischeri of 16 of 17 metabolizable compounds were negligible in the absence of added alkali-metal cations but rapid in the presence of Na. Only d-glucose uptake by V. fischeri occurred at a reasonable rate in the absence of alkali-metal cations, although the rate was further increased by added Na, K, or Li. Quantitative requirements for Na for the uptake of 11 metabolites by A. haloplanktis and of 6 metabolites by V. fischeri and the characteristics of the Na response at constant osmotic pressure varied with each metabolite and were different from the Na effects on the energy sources used. Li stimulated transport of some metabolites in the presence of suboptimal Na concentrations and for a few replaced Na for transport but functioned less effectively. K had a small capacity to stimulate lysine transport. The rate of transport of most of the compounds increased to a maximum at 50 to 300 mM Na, depending on the metabolite, and then decreased as the Na concentration was further increased. For a few metabolites, the rate of transport continued to increase in a biphasic manner as the Na concentration was increased to 500 mM. Concentrations of choline chloride equimolar to inhibitory concentrations of NaCl were either not inhibitory or appreciably less inhibitory than those of NaCl. All metabolites examined accumulated inside the cells against a gradient of unchanged metabolite in the presence of Na, even though some were very rapidly metabolized. The transport of l-alanine, succinate, and d-galactose into A. haloplanktis and of l-alanine and succinate into V. fischeri was inhibited essentially completely by the uncoupler 3,5,3',4'-tetrachlorosalicylanilide. Glucose uptake by V. fischeri was inhibited partially by 3,5,3',4'-tetrachlorosalicylanilide and also by arsenate and iodoacetate.
在没有添加碱金属阳离子的情况下，盐单胞菌对 19 种可代谢化合物的摄取率和发光杆菌对 16 种可代谢化合物中的 17 种的摄取率可忽略不计，但在存在 Na 的情况下则迅速增加。只有在没有碱金属阳离子的情况下，发光杆菌才会以合理的速度摄取 d-葡萄糖，尽管添加 Na、K 或 Li 会进一步提高摄取率。盐单胞菌摄取 11 种代谢物和发光杆菌摄取 6 种代谢物所需的 Na 定量要求以及在恒渗透压下 Na 响应的特征因每种代谢物而异，并且与对所用能源物质的 Na 效应不同。在亚最佳 Na 浓度下，Li 刺激一些代谢物的转运，对于少数几种代谢物，Li 可替代 Na 进行转运，但效果较差。K 对赖氨酸转运的刺激能力较小。大多数化合物的转运速率在 50 至 300 mM Na 时增加到最大值，具体取决于代谢物，然后随着 Na 浓度的进一步增加而降低。对于少数几种代谢物，随着 Na 浓度增加到 500 mM，转运速率继续呈双相增加。与等摩尔浓度的 NaCl 抑制浓度的氯化胆碱要么没有抑制作用，要么明显小于 NaCl 的抑制作用。在 Na 存在的情况下，所有检查的代谢物都在细胞内积累，形成不变代谢物的梯度，即使有些代谢物被非常迅速地代谢。l-丙氨酸、琥珀酸盐和 d-半乳糖进入盐单胞菌以及 l-丙氨酸和琥珀酸盐进入发光杆菌的转运都被解偶联剂 3,5,3',4'-四氯水杨酰苯胺基本完全抑制。3,5,3',4'-四氯水杨酰苯胺和砷酸盐以及碘乙酸盐部分抑制发光杆菌摄取葡萄糖。
