Manuel B. Manzanal

Incorporation and fate of N-acetyl-D-glucosamine during hyphal growth in Streptomyces

SUMMARY: N-AcetyI-D-[1-14C]glucosamine ([14C]GlcNAc) was used to label specifically the cell wall in Streptomyces antibioticus. Lysozyme solubilized 86.5% of the radioactivity present in the trichloroacetic acid-precipitated and RNAase plus trypsin-digested fraction of hyphae pulse-labelled with [14C]GlcNAc for 3 min in a medium containing glucose, yeast extract and a mixture of nine amino acids. Experiments with [14C]GlcNAc-labelled hyphae revealed that growth of Streptomyces occurs without turnover of peptidoglycan. Autoradiographic analysis of S. antibioticus hyphae indicated that cell wall elongation occurs by intercalation of newly synthesized wall polymers at the tip, but also over a relatively broad zone that, depending on the hyphal length, extends up to 6-10 μm from the tip.