114. Brown, Jr. R. M. 1987. The biosynthesis
of cellulose. Food Hydrocolloids, 1(5/6):345-351.
114. Abstract
To date, two basic cellulose synthesizing
structures (TCs) have been described, the linear TC, typical of
giant algae such as Boergesenia, Valonia and Eremosphaera
and the rosette TC characteristic of all vascular plants,
ferns, mosses and certain algae such as Chara, Nitella
and Mougeotia. Linear terminal complexes are transported
to the surface as subunits and later assembled into the linear
structure. These linear structures continue to grow in length
during microfibril assembly. The relationship of the TC structure
to microfibril dimensions is discussed. Rosette TCs appear to
be pre-assembled in the Golgi apparatus and transported to the
surface intact. The topographical localization of TC structure
in relation to patterns of microfibril deposition is described.
The structure of the TC is discussed in relation to the synthesis
of cellulose I and II. The biosynthesis of microbial cellulose
by Acetobacter xylinum is summarized. Recent evidence
for in vivo cellulose synthesis is given. The cellulose
synthesizing complexes are located on the inner cytoplasmic membrane
of Acetobacter and the regulatory proteins for controlling
microfibril assembly may be located on the outer lipopolysaccharide
membrane. Recent studies of in vitro synthesis
indicated that cellulose II is made in vitro, whereas cellulose
I is the more common allomorph produced in vivo.