TABLE 4.

HPLC analysis of muropeptides prepared from the peptidoglycans of P. aeruginosa PAO1 reference strain at exponential vs. stationary growth phases.

Strain and growth phase	Relative abundance (mol%) of muropeptidea							Cross-linkb (%)	Peptidoglycan lengthc
	Mono	Di	Tri	D-D	Lpp	Anh	Penta
PAO1 Exponential (OD600:0.75)	65.20	32.77	2.02	1.77	4.83	5.18	1.99	36.81	19.81
PAO1 Stationary (OD600 > 3)	64.15	33.78	2.10	2.65	12.35∗	8.17∗	8.38∗	37.92	12.33∗
XL1 blue Exponential (OD600:0.75)	63.25	35.30	1.47	4.23	6.95	5.11	7.10	38.25	19.60
XL1 blue Stationary (OD600 > 3)	59.76∗	36.57	3.67∗	12.2∗	8.30	5.22	5.33	43.90∗	19.20

^aMol%, molar fraction; Mono, monomers; Di, dimers; Tri, trimers; D-D, muropeptides having mDAP-mDAP crosslinking; Lpp, muropeptides bound to C-terminal Arg-Lys dipeptide of OprI or Braun’s lipoprotein; Anh, muropeptides having anhydro-1,6-anhydromuramic acid; Penta, muropeptides having a pentapeptide stem (all these pentapeptides were shown to possess glycine instead of D-alanine in terminal position). ^bCross-link, degree of peptidoglycan cross-linking (percentage). ^cAverage number of disaccharide (N-acetylglucosamine and N-acetylmuramic acid) units in the sacculus sugar chains of each strain. The displayed value of each parameter and strain is the mean obtained from two independent replicates of peptidoglycan extraction and HPLC analysis. In all the cases, the SD was below 20% of each value (data not shown). ^∗Statistically significant, P-value < 0.05 in the unpaired Student t-test, when comparing a given parameter between the two growth phases separately for each species.