Manzanera Maximino, Vilchez Susana, Tunnacliffe Alan
Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT, UK.
FEMS Microbiol Lett. 2004 Apr 15;233(2):347-52. doi: 10.1016/j.femsle.2004.03.005.
The tetrahydropyramidine hydroxyectoine acts as an osmolyte in a range of bacterial species, but its use as a desiccation protectant is less well explored. Recently, it was demonstrated that hydroxyectoine provides effective stabilisation of the Gram-negative species Pseudomonas putida, which is only relatively poorly preserved by the better-characterised protectant, trehalose. It is now shown that hydroxyectoine also protects the paradigmatic bacterium, Escherichia coli: osmotically-preconditioned E. coli dried in hydroxyectoine exhibited a high degree of desiccation tolerance, similar to that achieved using trehalose in this species. Hydroxyectoine is apparently accumulated from hypersaline medium in preference to trehalose biosynthesis, but E. coli loaded with hydroxyectoine in this way showed reduced stability in the dry state. This suggests that, although both hydroxyectoine and trehalose perform equally well as extracellular protectants, trehalose is preferred for intracellular protection.
四氢嘧啶羟基ectoine在一系列细菌物种中作为渗透溶质发挥作用，但其作为干燥保护剂的用途尚未得到充分探索。最近，有研究表明羟基ectoine能有效稳定革兰氏阴性菌恶臭假单胞菌，而在特性更明确的保护剂海藻糖作用下，该菌的保存效果相对较差。现在有研究表明，羟基ectoine还能保护典型细菌大肠杆菌：经渗透压预处理后在羟基ectoine中干燥的大肠杆菌表现出高度的干燥耐受性，与在该物种中使用海藻糖所达到的效果相似。羟基ectoine显然优先从高盐培养基中积累，而非进行海藻糖生物合成，但以这种方式负载羟基ectoine的大肠杆菌在干燥状态下稳定性降低。这表明，尽管羟基ectoine和海藻糖作为细胞外保护剂的效果相当，但海藻糖更适合用于细胞内保护。
