Condition of cell-wall mucopeptide in dividing and non-dividing cells of Micrococcus lysodeikticus dis-IIp+

Abstract

All chemicals tested (D-cycloserine, D-serine, penicillin, mitomycin c, hydroxylamine) that induce significant inhibition of cell division in Micrococcus lysodeikticus dis-IIp+ inhibit, to varying degrees, synthesis of mucopeptide and, also, cross-linking within cell-wall mucopeptide. Penicillin is, by far, the most efficient and possibly the only quantitatively important inhibitor of the cross-linking process. Two chemicals (pantoyl lactone and spermine) which prevent inhibition of division by D-cycloserine do not allow or bring about significant restoration of mucopeptide synthesis in cells growing in the presence of the antibiotic. D-Alanine, which prevents both the inhibition of growth and division caused by D-cycloserine, prevents also to a significant degree, the deleterious effects of D-cycloserine on mucopeptide synthesis and cross-linking. A possible interdependence between the cell wall and cell membrane in the division process is discussed. It is proposed that pantoyl lactone and spermine favor division activity because of physical effects on the cell membrane.