Mechanisms Involved in Bacterial Cellulose Biosynthesis

埃希氏菌和沙门氏菌形成高度耐药的生物膜，由纤维素和卷曲菌毛组成，这有助于这些细菌逃避免疫系统的检测，并增加它们对抗菌剂和恶劣环境因素的耐受性。纤维素成分特别赋予保护免受机械，化学和生物应力，并促进粘附到许多表面，如上皮细胞，各种食物，水分配系统等。因此，生物膜形成和组成的知识对于了解这些细菌如何在环境水库中建立自己至关重要，从而使它们能够继续威胁我们的食品/水安全，工业过程和一般健康。细菌纤维素也获得了生物工程的重要性，因为它具有独特的物理/化学性质，与藻类或植物来源的纤维素相比具有显著的优势。这些特性已被成功开发用于生产新型伤口敷料、生物塑料、生物燃料和用于组织再生的生物惰性支持物。尽管细菌纤维素的生物和工业意义正在扩大，但对细菌合成和输出这种聚合物知之甚少。遗传学研究表明，七个基因，bcsABZCEFG，是必不可少的纤维素的生物合成在肠道细菌。我们假设Bcs蛋白聚集在一起形成细菌细胞壁跨越复合物，促进协调聚合，出口和释放纤维素从细胞。使用大肠大肠杆菌作为一个模型系统，我们的目标是利用多学科的方法来表征这些过程中涉及的每一个蛋白质的结构和功能。这项研究的结果将是揭示绕过生物膜屏障的独特方法的关键，并将为设计具有医疗/工业应用特定特性的聚合物（或酶）奠定基础。同样重要的是，对纤维素合成/输出的详细了解将导致发现与多糖合成和跨细菌物种的生物膜发育相关的重要原理。

Escherichia and Salmonella species form highly resistant biofilms, composed of cellulose and curli fimbriae, that helps these bacteria elude detection by the immune system and increases their tolerance to antimicrobial agents and harsh environmental factors. The cellulose component specifically confers protection from mechanical, chemical and biological stresses and promotes adherence to a number of surfaces, such as epithelial cells, a variety of foods, water distribution systems and more. Thus, knowledge of biofilm formation and composition is of critical importance to understanding how these bacteria establish themselves in environmental reservoirs, thereby enabling them to continue to threaten our food/water security, industrial processes and general health. Bacterial cellulose is also gaining bioengineering significance as it has unique physical/chemical properties that provide significant advantages when compared to algal or plant derived cellulose. These properties have been successfully exploited for the generation of novel wound dressings, bio-plastics, biofuels and bio-inert supports for tissue regeneration. Even though the biological and industrial implications of bacterial cellulose are expanding, little is known about the synthesis and export of this polymer by bacteria. Genetic studies have demonstrated that seven genes, bcsABZCEFG, are essential for the biosynthesis of cellulose in Enteric bacteria. We hypothesize that the Bcs proteins come together to form a bacterial cell wall spanning complex that facilitates the coordinated polymerization, export and release of cellulose from the cell. Using E. coli as a model system, our goals are to utilize a multidisciplinary approach to characterize the structure and function of each of the proteins involved in these processes. The results of this research will be key to revealing unique approaches to circumvent the biofilm barrier and will and lay the groundwork for designing polymers (or enzymes) with specific properties for medical/industrial applications. Equally important, a detailed understanding of the synthesis/export of cellulose will lead to the discovery of important principles relating to polysaccharide synthesis and biofilm development across bacterial species.