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。纤维素可能是最广为人知的例子。纤维素纤维的强度和延伸性被用于造纸、薄膜技术、纺织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，作为稳定剂、增稠剂、胶凝剂和药理学，作为药物载体或作为生物活性物质用于治疗癌症、降低胆固醇、抗感染和伤口愈合。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(例如在开发新的生物材料方面)仍有可能出现。一种在这方面很少被研究的生物聚合物被称为城市胶。它是一种存在于植物细胞壁中的多糖，与纸的主要成分纤维素一起存在。据信，老茧的积累可以封闭细胞壁，形成抵御疾病和其他威胁的防御性屏障。它还可以通过与其他细胞壁多糖相互作用而作为基质或支架。我们知道老茧对植物很重要，因为改变老茧的积累会对生长和发育产生负面影响。为了进一步了解老茧如何发挥作用，我们首先要测定老茧在溶液中和与纤维素的混合物中的物理性质。其次，我们将控制植物细胞壁中的愈伤组织浓度，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老茧质在控制细胞壁的结构和机械性能方面的作用，并确定可用于改性纤维素基复合材料或生产新的环境友好材料的新成分。最后但并非最不重要的一点是，这项研究将提高我们对细胞壁中痂多糖的生物学作用的理解。从长远来看，这一知识可以帮助开发生物技术方法，以改变细胞壁的特性，旨在改善植物的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.