The Microcrystalline Structure of Cellulose in Cell Walls of Cotton, Ramie, and Jute Fibers as Revealed by Negative Staining of Sections

Abstract

With a new technique of negative staining of sections, it has been possible to observe directly, in ultrathin sections under the electron microscope, the original microcrystalline and microfibrillar structure of cellulose as it occurs in living cells. This method has advantages over the study of isolated fibers used so far by others, in that the original arrangement of microfibrils is better preserved, and their collapse into larger fibrillar units is prevented. With this method, the cell walls of ramie, jute, and cotton fibers have been studied. The size (diameter, 25 to 40 A) and the longitudinal periodicity observed in the single microfibrils and the orientation and spatial arrangement of the microcrystallite within the microfibrils are found to correspond with the latest models derived by others from data obtained by indirect methods such as X-ray diffraction. The microfibril size of about 35 A, found by measuring these structures in sections, agrees with the latest conclusions reached by others in recent work with isolated fibrils.

A review on systematic study of cellulose

“…High → resolution electron microscopy lattice imaging shows the crystalline organization of cellulose in wood fibrils. Negative staining (Heyn, 1966;Woodcock and Sarko, 1980) used in conjunction with electron microscopy shows occasional points along the fibril at which the heavy metal stain seemed to penetrate: it was postulated that non-glucose residues were located in these areas. This theory could be seen to be supported by the discovery, in 1961, that up to 50% of some sections of these native cellulose fibrils were composed of nonglucose units.…”

Advanced-Microscopy Techniques for the Characterization of Cellulose Structure and Cellulose-Cellulase Interactions

“…(9,(14)(15)(16)(17)(18)(19)(20) In these techniques, cellulose samples must be prepared through drying, coating or staining methods that render the samples compatible with electron microscopy. Despite the exquisite detail that can be gained from these imaging techniques and the wealth of knowledge that has already been obtained through them, the sample preparation procedures can introduce artefacts through modifications to the physical structure of cellulose, such as the collapse of the micro-and nanoporous structure of plant-derived cellulose, the recrystallization and aggregation of elementary microfibrils, or by disrupting the biomolecular interactions occurring at the interface of the insoluble cellulose, such as the dislodgement of proteins weakly adsorbed to the surface of cellulose fibrils.…”

The Structure of Cellulose Microfibrils in Valonia

“…Heyn (1966) suggested that is can penetrate into whatever regions water can penetrate; i.e., the stain can penetrate all the regions except the crystalline region. This principle is based on the fact that uranyl acetate does not stain crystalline cellulose and that the amorphous cellulose can take up only water and aqueous solutions (Heyn, 1966). On this principle, the translucent parts seen in the electron micrographs may indicate crystalline regions of cellulose.…”