show that supernatant harvested from the triple mutant, lacking LasA, LasB and AprA proteases, did not degrade gels, indicating that LasA, LasB or AprA protease is likely to be responsible for degradation. However, when supernatant from mutant PAO1 lacking the lasB or aprA genes was used the gel did degrade. Furthermore, the hydrogels were not degraded by the supernatant of mutant lacking lasR which controls the expression of lasB, lasA and aprA. When lasR is inactivated, lasB, lasA and aprA activity is disrupted and metalloproteases may not be released, thus explaining no degradation of the hydrogels. It was shown in literature that LasB activates protease IV which then activates LasA which could explain the delayed degradation observed in the case of PAO1 ΔlasB. A lasA mutant would be needed to further understand the action of these metalloproteases. A summary of the results from testing several P. aeruginosa PAO1 mutants is shown in Figure .