Cellulose synthesis by Acetobacter xylinum. I. Low molecular weight compounds present in the region of synthesis.

An analysis has been made of the low molecular weight fraction present in the region of cellulose synthesis in Acetobacter xylinum suspensions. A number of nucleic acid bases, nucleosides and nucleotides, together with alpha-glucose 1-phosphate and UDPG, were detected in various extracts of washed cells supplied with glucose. Since glucose-6-P could be detected in extracts of ultrasonically disrupted cells, but not in extracts of whole cells, it was concluded that separate pools of hexose phosphate exist in A. xylinum. Preferential release of alpha-glucose-1-P, UDPG and nucleotides was observed during ethanol and EDTA treatment of bacteria. Electron microscopic examination of treated and untreated cells revealed that extensive modification of the cell wall region occurred during such treatments. The results support the proposal that alpha-glucose-1-P, UDPG and nucleotide pools are localised in the cell envelope region, possibly in the periplasm, and that A. xylinum possesses a second permeability barrier outside the cytoplasmic membrane. Nucleic acid bases and nucleosides were observed to diffuse freely through the cell wall and accumulate in the medium, probably as the result of nucleic acid breakdown. The results imply that the effects of cell damage caused by the isolation of the bacteria from the surface pellicle of the culture medium, together with nutrient deprivation, should be considered in work using the non-proliferating system. A stydy of the variation in concentration with time of alpha-glucose-1-P and UDPG, during cellulose synthesis, indicated that both components may play an immediate role in cellulose synthesis. Glycosylated lipid compounds were detected in both cell wall extracts and supernatant fluid, but it is not certain whether these compounds are constituents of the supernatant fluid in vivo.