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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Bacterial stalks are nutrient-scavenging antennas
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Bacterial stalks are nutrient-scavenging antennas

机译：细菌茎是营养清除天线

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摘要

Environmental inorganic phosphorus is frequently the growth-limiting nutrient for aquatic microorganisms, and there is fierce interspecies competition for the available supply. What are the limiting factors in effective bacterial scavenging of environmental phosphorus? It depends on the concentration. When the supply is relatively high, the limit is determined by the number of phosphate transporters on the surface times their individual throughput. At very low concentrations, however, the physics of diffusion at small scales comes into play. A relatively sparse distribution of transporters on the cell surface can capture every molecule that approaches the surface and phosphate influx becomes diffusion-limited. The prosthecate (stalked) bacteria, such as Caulobacter crescentus, have evolved an effective fitness strategy for these low-phosphorus environments that are dissected by Wagner et al. (1) in this issue of PNAS. Long, slender stalks extend the effective surface area of the cell, acting as a sort of nutrient-collecting antenna while adding little to the cell volume (Fig. 1). Thus, the cell's phosphate collection effectiveness is greatly increased at low cost. This hypothesis for the stalk's function was suggested by observations 40 years ago that the prosthecate bacteria grow much longer stalks in phosphate-limited media.
机译：环境无机磷通常是限制水生微生物生长的养分，并且种间竞争激烈，争夺可用的供应量。有效细菌清除环境磷的限制因素是什么？这取决于浓度。当供应量相对较高时，限制取决于表面上磷酸盐转运蛋白的数量乘以其各自的产量。然而，在非常低的浓度下，小规模扩散的物理就起作用了。转运蛋白在细胞表面的相对稀疏分布可以捕获接近该表面的每个分子，磷酸盐的流入受到扩散限制。假牙（茎）细菌，如新月形杆菌（Caulobacter crescentus），已发展出针对这些由Wagner等人解剖的低磷环境的有效适应策略。 （1）本期PNAS。长而细长的茎延长了细胞的有效表面积，在不增加细胞体积的情况下充当了一种营养收集天线（图1）。因此，以低成本大大提高了细胞的磷酸盐收集效率。 40年前的观察表明，假体细菌在磷酸盐限制的培养基中长出了更长的茎，这一假说是关于茎功能的。

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