ROLE OF AUTOLYSINS IN THE EDTA-INDUCED LYSIS OF PSEUDOMONAS-AERUGINOSA

Authors
Citation
Sr. Watt et Aj. Clarke, ROLE OF AUTOLYSINS IN THE EDTA-INDUCED LYSIS OF PSEUDOMONAS-AERUGINOSA, FEMS microbiology letters, 124(1), 1994, pp. 113-119
Citations number
23
Categorie Soggetti
Microbiology
Journal title
ISSN journal
03781097
Volume
124
Issue
1
Year of publication
1994
Pages
113 - 119
Database
ISI
SICI code
0378-1097(1994)124:1<113:ROAITE>2.0.ZU;2-4
Abstract
Treatment of Pseudomonas aeruginosa with metal ion chelators, especial ly ethylenediaminetetraacetic acid (EDTA), causes both release of prot ein-lipopolysaccharide complexes and cell death. We have examined the effect of EDTA on P. aeruginosa and found that EDTA does not induce th e rapid solubilization of the peptidoglycan sacculus and complete lysi s as previously thought; the decrease in optical density of cultures i ncubated with EDTA is primarily due to the loss of the outer membrane. Of the other potential solubilizers examined, only ethylene-bis(oxyet hylenenitrilo)tetraacetic acid (EGTA) resulted in some decrease in opt ical density. The lytic effect of EDTA on 12 strains of P. aeruginosa was examined and was found to vary greatly between strains; the sensit ivity to EDTA varies from between 96% and 10% of the decrease in optic al density resulting from incubation of cells with both EDTA and lysoz yme. Sensitivity to EDTA is not constant during the growth of P. aerug inosa; in the early exponential phase of growth, cells treated with ED TA exhibit a 82% decrease in optical density after 30 min while in the stationary phase the optical density decreases by only 40%. Nucleic a cids were observed to leak from cells following treatment with EDTA an d this was greatly facilitated by DNase and RNase. The release of gene tic material was much reduced when cells were incubated at 4 degrees C , supporting an enzymatic role in cell wall solubilization. We propose that only small areas of the sacculus become hydrolysed via specific peptidoglycan hydrolases, or autolysin(s), which are activated or de-r egulated by EDTA.