The extraordinary desiccation resistance of the opportunistic human pathogen Acinetobacter baumannii is a key to its survival and spread in medical care units. The accumulation of compatible solute such as glutamate, mannitol and trehalose contributes to the desiccation resistance. Here, we have used osmolarity as a tool to study the response of cells to low water activities and studied the role of a potential inorganic osmolyte, K⁺, in osmostress response. Growth of A. baumannii was K⁺‐dependent and the K⁺‐dependence increased with the osmolarity of the medium. After an osmotic upshock, cells accumulated K⁺ and K⁺ accumulation increased with the salinity of the medium. K⁺ uptake was reduced in the presence of glycine betaine. The intracellular pools of compatible solutes were dependent on the K⁺ concentration: mannitol and glutamate concentrations increased with increasing K⁺ concentrations whereas trehalose was highest at low K⁺. After osmotic upshock, cells first accumulated K⁺ followed by synthesis of glutamate; later, mannitol and trehalose synthesis started, accompanied with a decrease of intracellular K⁺ and glutamate. These experiments demonstrate K⁺ uptake as a first response to osmostress in A. baumannii and demonstrate a hierarchy in the time‐dependent accumulation of K⁺ and different organic solutes.

中文翻译：

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鲍曼不动杆菌中对渗透压的第一个反应：K +的瞬时积累及其被相容性溶质替代。

机会性人类病原体鲍曼不动杆菌的超强抗干燥性是其生存和在医疗单位中传播的关键。相容性溶质（如谷氨酸，甘露醇和海藻糖）的积累有助于抗干燥性。在这里，我们使用渗透压作为研究细胞对低水分活动的响应的工具，并研究了潜在的无机渗透压K ⁺在渗透压响应中的作用。鲍曼不动杆菌的生长是K ⁺依赖性的，并且K ⁺依赖性随着培养基渗透压的增加而增加。渗透性冲击后，细胞积累了K ⁺和K ⁺积累随着培养基盐度的增加而增加。ķ ⁺摄取甘氨酸甜菜碱的存在下还原。相容性溶质的细胞内池取决于K ⁺浓度：甘露醇和谷氨酸的浓度随K ⁺浓度的增加而增加，而海藻糖在低K ⁺时最高。渗透上升后，细胞首先积累K ^+，然后合成谷氨酸。后来，甘露醇和海藻糖开始合成，伴随着细胞内K ⁺和谷氨酸的减少。这些实验证明了钾⁺吸收是鲍曼不动杆菌对渗透压的第一个反应。并展示了K ⁺和不同有机溶质随时间的累积的层次结构。