Growth-Related Esterification of Plant Cell Wall Pectins

果胶是高等植物细胞壁的主要结构多糖，具有极大的复杂性。它们被认为在细胞的生物学中起着多种作用，与细胞壁水化、可塑性和细胞粘附有关。果胶似乎也参与了植物的防御反应。这个项目将研究在细胞生长过程中发生的果胶化学结构的一些详细变化。特别要注意的是玉米细胞中脲酸残基的酯化反应的具体类型，以及随着细胞的生长这种反应是如何变化的。有证据表明，酯化的半乳糖醛酸单元不能完全由甲酯来解释，因此需要进一步的工作来更充分地表征这些酯化的化合物。该项目旨在阐明酯化的细节，以及这些可能与与细胞扩大相关的果胶酯化产生的多糖相互作用有关。高等植物的细胞壁在很大程度上负责植物的支持，是植物形态的主要决定因素。植物细胞壁由许多复杂的聚合碳水化合物组成，包括纤维素、半纤维素和果胶化合物。果胶化合物是由一系列以复杂模式连接在一起的糖酸组成的聚合化合物。这些果胶化合物在生长过程中其化学结构发生了微妙的变化，这些变化可能在决定植物细胞如何能够在大小上生长方面起着重要作用。在这个项目中，Carpita博士继续详细探索玉米果胶的化学成分，利用最先进的技术全面表征这些重要的化合物

Pectins are major structural polysaccharides of the cell wall in higher plants and are of enormous complexity. They have been thought to play a multiplicity of roles in the biology of the cell in connection with wall hydration, plasticity and cell adhesion. Pectins also appear to be involved in plant defense responses. This project will examine some of the detailed modifications in chemical structure of pectins that take place during cell growth. Particular attention is to be paid to the specific type of esterification of uronic acid residues in maize cells and how this changes as the cells grow. Evidence that the esterified galactosyluronic acid units cannot be completely accounted for by methyl esters leads to the need for further work to characterize more fully these esterified compounds. This project is intended to elucidate details of esterification and how thesse may relate to polysaccharide interactions resulting from the pectin esterifications that are associated with cell enlargement. The cell wall of higher plants is largely responsible for the support of plants and is a major determinant of the form of plants. Plant cell walls comprise of a number of complex polymeric carbohydrates, including cellulose, hemicellulose and pectic compounds. Pectic compounds are polymeric compounds consisting of a series of sugar-acids that are linked together in complex patterns. These pectic compounds undergo subtle changes in their chemical structure during growth, and these changes may play an important role in determining how plant cells are able to grow in size. In this project Dr. Carpita continues his detailed exploration of the chemistry of maize pectins, making use of state-of- the-art technology in fully characterizing these important compounds.***//