59. Romanovicz, D. K. and R. M. Brown, Jr. 1976. Biogenesis and structure of Golgi-derived cellulosic scales in Pleurochrysis. II. Identification of the scale subcomponents, with reference to cytochemical enzyme localization and the supermolecular structure of the cellulosic microfibril. Applied Polymer Symp. 28:587-610. John Wiley & Sons, Inc., New York.

59. Synopsis

Intact Pleurochrysis scales can be obtained in cell-free preparations for physical and chemical characterization. Isolation of the scale subcomponents has been achieved by serial extraction with trifluoroacetic acid, correlated with negative staining to observe the extent of extraction. Compositional analysis of the radial and amorphous subcomponents has revealed the presence of glucose, galactose, arabinose, and fucose, as well as a peptide constituent amounting to approximately 10% by weight. The spiral microfibrils are cellulosic, as confirmed by infrared absorption and x-ray diffraction, and are coated with glycopeptide rich in hydroxyproline. Observations of negatively stained preparations of isolated scales demonstrate that the intact cellulosic microfibril is a continuous ribbon 37 x 50 Angstroms in cross-section and attaining a length of approximately 14 microns. With improved techniques yielding higher resolution (Bacitracin, uranyl acetate), the individual cellulose microfibril is resolved into four apparent protofibrils each 12 x 16 Angstroms in cross-section. From these data, a macromolecular model of scale cellulose is proposed, incorporating assumptions about the protein moiety derived from positive staining characteristics, and crystallinity data calculated form wide angle x-ray diffraction and infrared absorption.

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Last modified 27 October 2005.
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