Reassembly of the Regularly Arranged Subunits in the Cell Wall ofLactobacillus brevisand Their Reattachment to Cell Walls

Abstract

The reassembly of tetragonally arranged subunits in the cell wall of Lactobacillus brevis and the reattachment of the subunits to cell wall fragments were investigated by electron microscopy. The subunits dissociated from the cell wall with guanidine hydrochloride (GHCl) reassembled into the same regular array as seen in native cell wall after dialysis against neutral buffer even in the absence of specific cations. The subunits could also reattach to the cell wall fragments from which they had been removed by treatment with GHCl, sodium dodecyl sulfate or cold trichloroacetic acid but not to those treated with hot formamide. Heterologous reattachment of the subunits occurred on cell wall fragments obtained from L. fermentum but not on those from L plantarum or L. casei subsp. casei. On the basis of these observations and chemical analyses of the cell wall fragments, the subunits of L. brevis appeared to be bound by hydrogen bonds to a neutral polysaccharide moiety in the cell wall but not to peptidoglycan or teichoic acid.