CELLULOSE BIOSYNTHESIS IN ACETOBACTER-XYLINUM - VISUALIZATION OF SITE OF SYNTHESIS AND DIRECT MEASUREMENT OF INVIVO PROCESS

In vivo synthesis of cellulose by A. 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 .mu.m min-1. The ribbon consists of .apprx. 46 microfibrils which average 1.6 .times. 5.8 nm in cross section. The observed microfibrillar elongation rate corresponds to 470 a[at to]mol of glucose/cell per h assimilated into cellulose. EM of the process using negative staining, sectioning and freeze-etching indicated the presence of .apprx. 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 plant cells.