66. Brown, Jr. R. M., Willison, J. H. M.,
and C. L. Richardson. 1976. Cellulose biosynthesis in Acetobacter
xylinum: 1. Visualization of the site of synthesis and direct
measurement of the in vivo process. Proc. Nat. Acad.
Sci. U.S.A. 73(12):4565-4569.
synthesis of cellulose by Acetobacter xylinum was monitored
by darkfield light microscopy. Cellulose is synthesized in the
form of a ribbon projecting from the pole of the bacterial rod.
The ribbon elongates at a rate of 2 m min-1. The
ribbon consists of approximately 46 microfibrils which average
1.6 x 5.8 nm in cross section. The observed microfibrillar elongation
rate corresponds to 470 amol of glucose/cell per hr assimilated
into cellulose. Electron microscopy of the process using negative
staining, sectioning, and freeze-etching indicated the presence
of approximately 50 individual synthetic sites organized in a
row along the longitudinal axis of the bacterial rod and in close
association with the outer envelope. The process of cellulose
synthesis in Acetobacter is compared with that in eukaryotic