ACYL TYPE OF BACTERIAL CELL WALL: ITS SIMPLE IDENTIFICATION BY COLORIMETRIC METHOD

Abstract

A simple and practical method was studied to identify the acyl type of bacterial cell wall. The method is based on the determination of glycolic acid derived from the acid hydrolysis of a small amount of bacterial cells. The devised system with microcolumns was useful for quantitative separation of glycolic acid from complex materials in cell hydrolysate and glycolic acid was determined by colorimetric method of Calkins. Experiments showed that about 50-60 nmol of glycolyl residue was present in 1 mg dry cells in strains such as Cornynebacterium equi Aj 1402 (ATCC 6939), Brevibacterium imperiale AJ 1446 (IAM 1654), and B. testaceum AJ 1464 (IAM 1537), but the acid was scarcely found in C. diphtheriae AJ 1414 (ATCC 11913), Nocardia madurae AJ 9136 (NRRL B-2127) and so on. No acyl group other than glycolyl and acetyl residues or only acetyl group was detected in the purified cell wall of various bacteris tested. Bacteria are classified into glycolyl type or acetyl type relative to their cell-wall acyl type, which can be easily decided by estimation of glycolyl group in the whole bacterial cells.