Predator-prey interactions in aerobic granulation systems

Interspecies interactions and biofilm development in a three-species biofilm model

“…These are biosurfactants, which can lyse protozoa to prevent biofilm grazing and protect susceptible members from predation. Chan (2018) showed discovered that there was an additional mechanism contributing to the grazing resistance as protozoa were also killed by the rhamnolipid deficient P. aeruginosa biofilms. The protection was proposed to be contact dependent but this additional mechanism of toxicity to protozoa was unknown.…”

“…The model has been used in an experimental investigation to demonstrate cooperative behaviour and establish that enhanced stress tolerance against environmental exposures, especially antibiotic exposure and protozoa predation, by an insensitive member extended equally to all three community members (Chan, 2018;. Chan (2018) observed enhanced tolerance in the mixed-species biofilm to the protozoa, T.…”

“…In a previous study, the grazing resistance of both single and mixed species biofilms consisting of Pseudomonas.aeruginosa PAO1, Klebsiella pneumoniae KP-1 and Pseduomonas protegens Pf-5 to the heterotrophic ciliate, T. pyriformis, a ciliate that feeds both on planktonic cells as well as biofilms, were previously examined (Chan, 2018). The results demonstrated that both K. pneumoniae and P. protegens were sensitive to grazing pressure and had reduced biofilm biomass after the single species biofilms were subjected to grazing.…”

“…The cross protection extended by P. aeruginosa to other members in the mixed species biofilms was examined to elucidate any underlying resistance mechanism. Chan (2018) showed that the grazing resistance was partially due to rhamnolipid secretion, a biosurfactant which can lyse protozoa to prevent biofilm grazing and protect susceptible members from predation in the three species biofilm. Chan (2018) tested the biofilms of P. aeruginosa PAO1∆rhlA∆pscJ, a PAO1 mutant deficient in the type III secretion system (T3SS) baseplate for protozoa toxicity and it remained resistant to protozoa grazing, signifying that T3SS was not responsible for contact-dependent killing.…”

“…Chan (2018) showed that the grazing resistance was partially due to rhamnolipid secretion, a biosurfactant which can lyse protozoa to prevent biofilm grazing and protect susceptible members from predation in the three species biofilm. Chan (2018) tested the biofilms of P. aeruginosa PAO1∆rhlA∆pscJ, a PAO1 mutant deficient in the type III secretion system (T3SS) baseplate for protozoa toxicity and it remained resistant to protozoa grazing, signifying that T3SS was not responsible for contact-dependent killing. While rhamnolipids were discovered to be the primary secreted mechanism of predation defence, it was clear that P. aeruginosa produced a secondary mechanism that was biofilm associated.…”