Mechano-physical properties of the biopolymer callose: a matrix and a sealant?

许多可生物降解和可回收材料的制造是基于从植物材料（主要是细胞壁）中提取的天然生物聚合物的性质。纤维素可能是最著名的例子。纤维素纤维的强度和延展性用于造纸、膜技术、纺织品和新型绷带材料的生产。其他植物生物聚合物（如淀粉和果胶）在食品工业中也有重要的应用，如稳定剂、增稠剂、胶凝剂，在药理学中也有重要的应用，如药物输送载体或治疗癌症、降低胆固醇、抗感染和伤口愈合的生物活性剂。显然，天然生物聚合物已经对现代社会产生了积极的影响。随着对其结构、化学和物理性质的进一步了解，新的工业应用（例如开发新型生物材料）仍将出现。在这方面研究较少的一种生物聚合物称为胼胝质。它是一种多糖，存在于植物细胞壁中，含有纤维素，是纸张的主要成分。胼胝质的积累被认为可以封闭细胞壁，形成抵御疾病和其他威胁的防御屏障。它也可以通过与其他细胞壁多糖相互作用而充当基质或支架。我们知道胼胝质对植物很重要，因为改变胼胝质的积累会对生长和发育产生负面影响。为了进一步了解胼胝质的功能，我们将首先确定胼胝质在溶液中以及与纤维素混合物中的物理性质。其次，我们将操纵植物细胞壁中的胼胝质浓度，并检测细胞壁弹性和细胞壁组成的变化。这些分析的结果将表明胼胝质在控制细胞壁的结构和机械性能中的作用，并确定可用于修改纤维素基复合材料或生产新的环境友好型材料的新组件。最后但并非最不重要的是，这项研究将提高我们对细胞壁中胼胝质生物学作用的理解。从长远来看，这些知识可以帮助开发生物技术方法来改变细胞壁特性，旨在改善植物发育和保护免受环境威胁。

The manufacture of many biodegradable and recyclable materials is based on the properties of natural biopolymers extracted from plant material (mainly cell walls). Cellulose is perhaps the most-well known example. The strength and extensibility of cellulose fibres is used in paper manufacturing, membrane technology, textiles and for the production of novel bandage materials. Other plant biopolymers (such as starch and pectins) also have important applications in the food industry, as stabilizers, thickeners, gelation agents and in pharmacology, as carriers for drug delivery or as bioactive agents in the treatment of cancer, cholesterol reduction, infection resistance and wound healing.Clearly natural biopolymers have already made a positive impact on modern societies. With further understanding of their structural, chemical and physical properties, new industrial applications (for example in the development of novel biomaterials) can still emerge.One biopolymer that has been little studied in this respect is called callose. It is a polysaccharide that occurs in plant cell walls with cellulose, the major component of paper. Callose accumulation is believed to seal off cell walls forming a defensive barrier against disease and other threats. It may also act as a matrix or scaffold by interacting with other cell wall polysaccharides. We know callose is important for plants because altered callose accumulation show negative effects in growth and development.To get further insight on how callose functions we will first determine the physical properties of callose in solution and in mixtures with cellulose. Secondly, we will manipulate callose concentration in plant cell walls and detect changes in cell wall elasticity and in cell wall composition. Results from these analyses will indicate the role of callose in controlling the structural and mechanical properties of cell walls and identify new components that could be used to modify cellulose-base composites or to produce new environmentally friendly materials. Last but not least, the research will improve our understanding of the biological role of callose in cell walls. In the long term this knowledge could aid the development of biotechnological approaches to modify cell wall properties aiming to improve plant development and protection against environmental threats.