Regulatory mechanisms involved in cellulose biosynthesis by acetic acid bacteria

醋酸菌（AAB）在许多生物技术应用中具有重要意义，包括合成纤维素，纤维素是一种β-1，4-连接的吡喃葡萄糖残基的无支链聚合物。由AAB合成的纤维素具有独特的纳米形态，由纳米纤维的超细网络组成，有助于其拉伸强度和高度结晶结构。由于细菌纤维素的独特性质，它具有许多工业应用，如食品，造纸，制药和作为生物燃料生产的原料。AAB可以从水果和花中分离出来;然而，纤维素在这种植物-微生物相互作用中的作用尚不清楚。细胞外纤维素是许多病原体的生物膜结构的重要组成部分，其促进附着并提供保护。尽管纤维素作为微生物生存策略的明显重要性，但包括输出和最终组装成结晶形式的生物合成途径尚未阐明。该研究计划的长期目标是阐明细菌纤维素的完整生物合成途径，并了解不仅影响纤维素合成而且影响纤维素理化性质的多层次调控。这些知识是理解细菌纤维素在微生物-植物相互作用中的作用以及纤维素特性如何影响细菌在环境中生存的关键。由于细菌纤维素具有许多实际的工业应用，从这项研究计划中获得的知识将是工程纤维素材料的基础，具有独特的性能，可用于各种应用。该授权期的具体目标是：1）表征能够在纤维素合成抑制剂存在下合成纤维素的突变体; 2）表征吲哚-3-乙酸和脱落酸在调节纤维素合成中的功能作用; 3）阐明乙酸细菌响应影响纤维素生产的环境信号所使用的调节回路。该研究计划将为微生物学，分子生物学，遗传学，蛋白质组学，生物化学和材料科学领域的高素质人才提供跨学科培训。

Acetic acid bacteria (AAB) are important for many biotechnological applications including synthesis of cellulose, an unbranched polymer of ß-1,4-linked glucopyranose residues. Cellulose synthesized by AAB has a unique nanomorphology consisting of an ultrafine network of nanofibres that contribute to its tensile strength and highly crystalline structure. Due to the unique properties of bacterial cellulose, it has many industrial applications such as food, paper, pharmaceuticals, and as a feedstock for biofuel production. AAB can be isolated from fruits and flowers; however, the role cellulose plays in this plant-microbe interaction is not known. Extracellular cellulose is a crucial component of the biofilm structure of many pathogens facilitating attachment and providing protection. Despite the obvious importance of cellulose as a microbial survival strategy, the biosynthetic pathway including export and final assembly into the crystallized form are yet to be elucidated. The long-range goal of this research program is to elucidate the complete biosynthetic pathway of bacterial cellulose and to understand the multiple levels of regulatory control that affect not only the synthesis but also the physicochemical properties of cellulose. This knowledge is key to understanding the role bacterial cellulose plays in microbe-plant interactions and how the cellulose properties affect bacterial survival in the environment. Since bacterial cellulose has many practical industrial applications, the knowledge gained from this research program will be fundamental in engineering cellulosic materials with unique properties for diverse applications. The specific objectives for this granting period will be to 1) characterize mutants able to synthesize cellulose in the presence of cellulose synthesis inhibitors; 2) characterize the functional role of indole-3-acetic acid and abscisic acid in regulating cellulose synthesis; 3) elucidate regulatory circuits used by acetic acid bacteria in response to environmental signals that affect cellulose production. This research program will provide interdisciplinary training to highly qualified personnel in the areas of microbiology, molecular biology, genetics, proteomics, biochemistry and material science.