The metabolic cost of flagellar motion in Pseudomonas putida KT2440
The metabolic cost of flagellar motion in Pseudomonas putida KT2440
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DOI：
10.1111/1462-2920.12309
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发表时间：
2014-01-01
影响因子：
5.1
通讯作者：
de Lorenzo, Victor
中科院分区：
文献类型：
--
作者：
Martinez-Garcia, Esteban;Nikel, Pablo I.;de Lorenzo, Victor
虽然环境细菌的鞭毛机制赋予了细胞非凡的生存装置，但它也消耗了大量的代谢货币，为这种充满活力的纳米马达提供燃料。通过对土壤细菌恶臭假单胞菌dakt2440基因组中约70kb的DNA片段（约1.1%）的缺失，其中包括该微生物的相关结构和调控基因，对其鞭毛相关功能的生理成本进行了检测和量化。该菌株缺乏野生型恶臭p.p putida菌株中定义鞭毛的突出的极性绳，并且无法进行任何游泳运动，同时显示出明显的表面疏水性变化。然而，这些缺陷同时伴随着明显的生理优势：缺失菌株对糖酵解和糖异生碳源的快速适应，能量电荷的增加，最显著的是，对氧化应激的耐受性提高，反映了NADPH/NADP（+）比值的增加。这些特性提高了非鞭毛细胞对富培养基中快速生长的代谢疲劳的耐受力。因此，鞭毛运动代表了典型的以相当大的代谢负担为代价获得环境优势的权衡。
Although the flagellar machinery of environmental bacteria endows cells with a phenomenal survival device, it also consumes much of the metabolic currency necessary for fuelling such a vigorous nano-motor. The physiological cost of flagella-related functions of the soil bacterium Pseudomonas putidaKT2440 was examined and quantified through the deletion of a approximate to 70kb DNA segment of the genome (approximate to 1.1%), which includes relevant structural and regulatory genes in this micro-organism. The resulting strain lacked the protruding polar cords that define flagella in the wild-type P.putida strain and was unable of any swimming motility while showing a significant change in surface hydrophobicity. However, these deficiencies were otherwise concomitant with clear physiological advantages: rapid adaptation of the deleted strain to both glycolytic and gluconeogenic carbon sources, increased energy charge and, most remarkably, improved tolerance to oxidative stress, reflecting an increased NADPH/NADP(+) ratio. These qualities improve the endurance of non-flagellated cells to the metabolic fatigue associated with rapid growth in rich medium. Thus, flagellar motility represents the archetypal tradeoff involved in acquiring environmental advantages at the cost of a considerable metabolic burden.