Oriented fragmentation of Escherichia coli sacculi by sonication.

Isolated murein sacculi of Escherichia coli PA3092 were physically ruptured by sonication. Electron microscopical analysis showed that the rupturing occurred preferentially prependicular to the long axis of the cell. The fragmentation of the sacculi increased with longer sonication times. It was found that the extent of cross-linkage was more affected by the sonication than was the average glycan chain length. These data confirm earlier observations and indicate that the glycan chains run predominantly perpendicular to the long axis of the cell. By contrast, the peptide cross-links are more dispersely oriented.