Prieto Auxiliadora, Escapa Isabel F, Martínez Virginia, Dinjaski Nina, Herencias Cristina, de la Peña Fernando, Tarazona Natalia, Revelles Olga
Department of Environmental Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, 28040, Spain.
Environ Microbiol. 2016 Feb;18(2):341-57. doi: 10.1111/1462-2920.12760. Epub 2015 Feb 11.
Polyhydroxyalkanoate (PHA) metabolism has been traditionally considered as a futile cycle involved in carbon and energy storage. The use of cutting-edge technologies linked to systems biology has improved our understanding of the interaction between bacterial physiology, PHA metabolism and other cell functions in model bacteria such as Pseudomonas putida KT2440. PHA granules or carbonosomes are supramolecular complexes of biopolyester and proteins that are essential for granule segregation during cell division, and for the functioning of the PHA metabolic route as a continuous cycle. The simultaneous activities of PHA synthase and depolymerase ensure the carbon flow to the transient demand for metabolic intermediates to balance the storage and use of carbon and energy. PHA cycle also determines the number and size of bacterial cells. The importance of PHAs as nutrients for members of the microbial community different to those that produce them is illustrated here via examples of bacterial predators such as Bdellovibrio bacteriovorus that prey on PHA producers and produces specific extra-cellular depolymerases. PHA hydrolysis confers Bdellovibrio ecological advantages in terms of motility and predation efficiency, demonstrating the importance of PHA producers predation in population dynamics. Metabolic modulation strategies for broadening the portfolio of PHAs are summarized and their properties are compiled.
传统上，聚羟基脂肪酸酯（PHA）代谢被认为是一个参与碳和能量储存的无效循环。与系统生物学相关的前沿技术的应用，增进了我们对诸如恶臭假单胞菌KT2440等模式细菌中细菌生理学、PHA代谢与其他细胞功能之间相互作用的理解。PHA颗粒或碳体是生物聚酯和蛋白质的超分子复合物，对于细胞分裂过程中的颗粒分离以及PHA代谢途径作为一个连续循环的运作至关重要。PHA合酶和解聚酶的同时活性确保了碳流向代谢中间体的瞬时需求，以平衡碳和能量的储存与利用。PHA循环还决定了细菌细胞的数量和大小。本文通过诸如噬菌蛭弧菌等细菌捕食者的例子，说明了PHA作为与产生它们的微生物群落不同的微生物群落成员的营养物质的重要性，噬菌蛭弧菌捕食PHA生产者并产生特定的细胞外解聚酶。PHA水解在运动性和捕食效率方面赋予了蛭弧菌生态优势，证明了PHA生产者捕食在种群动态中的重要性。总结了用于拓宽PHA种类的代谢调控策略，并汇编了它们的特性。
