It has also been reported that the turnover rate and
the amount of cell wall material vary among species and
even strains. Reith et al. (2011) reported that the magnitude
of cell wall turnover is also dependent on the growth conditions. In addition, the capability of microorganisms in the
recycling of cell wall material also affected the amount of
peptidoglycan detected in the extracellular and intracellular
extracts (Litzinger et al. 2010). Our current study demonstrated that all strains contain a total peptidoglycan amount
ranging from 0.241 to 0.425 μg/mL. Although larger
amounts of peptidoglycan, in the range of 10–100 μg/mL
are necessary to stimulate cellular responses, peptidoglycan
has also been reported to be effective at lower concentrations, via synergism with LTA (Yang et al. 2001). It is
postulated that peptidoglycan at concentrations as low as
0.24 μg/mL in the presence of LTA is sufficient to induce
production of antimicrobial peptides in keratinocytes.