Actinomyces viscosus cell-free synthesis of extracellular slime polysaccharide

A cell-free extract of Actinomyces viscosus T14Av catalyzed the synthesis of extracellular N-acetylglucosamine-rich slime polysaccharide. The activity was localized in the cytoplasmic membrane fraction and required the presence of ADP-glucose and UDP-N-acetylglucosamine. Maximal activity was demonstrated at pH 7.5 and also required the presence of divalent cations such as Mg2+ or Mn2+. Extracellular slime appeared to serve as a primer for slime biosynthesis. The antibiotic tunicamycin acted as an inhibitor of slime formation. However, another glucosamine analogue, amphomycin, as well as the antibiotic bacitracin produced moderate stimulatory effects on slime biosynthesis.