culprits and strategies OEST 740

Transcription

1 Biofilm Predation: culprits and strategies OEST

2 Outline Introduction Bacteria Predators Protist Predators Viral - parasitic Conclusion/Summary

3 Predation All +/- interactions in which one organism consumers all or part of another Predatory-prey Herbivore-plant Parasite-host Linkages are primary pathways of energy through h food chains Important ecological factors Population ecology Prey mortality Predatory growth Important evolutionary force

4 Bacteria Predators Bdellovibrio bacteriovorus Gram negative, motile, uniflagellated Obligatory parasitic life cycl Broad host range bacteria specific (Kadouri & O Toole 2005)

5 B. bacteriovorus Variable susceptibility between planktonic and biofilm bacteria (Kadouri & O Toole 2005)

6 B. bacteriovorus (Kadouri & O Toole 2005)

7 Summary The bacterium B. bacteriovorus was able to attack E. coli biofilms of various thickness suggesting that the action of the predator was not restricted to surface The predator not only survived in biofilms but could feed, proliferate and escape Biofilm bacteria were more resistant to predation than planktonic counterpart No stable resistant population was achieved

8 Bacteria Predators Micavibrio aeruginosavorus Obligatory parasitic life cycle Host specific (Kadouri et al. 2007)

9 Micavibrio aeruginosavorus (Kadouri et al. 2007)

10 Micavibrio aeruginosavorus Adks;jfna (Kadouri et al. 2007)

11 Micavibrio aeruginosavorus (Kadouri et al. 2007)

12 Summary The bacteria exoparasite M. aeruginosavorus can reduce existing P. aeruginosa biofilms of both laboratory and clinical strains. Also, attacks two other opportunistic human pathogens, B. cepacia and K. pneumoniae No difference in predator ability to attack biofilm vs. planktonic cells P. aeruginosa has ability to adapt to environmenal predation by developing grazing-resistant macrocolonies

13 Protozoan Predators Impact of flagellate grazing on P. aeruginosa (Matz & Kjelleberg 2005)

14 Summary Suggests involvement of locomotory traits, exopolymers and QS in the formation of inedible microcolonies Formation of microcolonies in early biofilm formation Effective against size specific predators Acute toxicity production at later stages QS regulated Protect against wide range of predators

15 Protozoan Predators Resistance of V. cholerae biofilms during flagellate grazing (Matz et al. 2005)

16 Protozoan Predators Inhibition of flagellate growth by V. cholerae biofilms (Matz et al. 2005)

17 Protozoan Predators Stimulation of biofilm formation by planktonic grazers Niche-specificity as a result of grazing pressure (Matz et al. 2005)

18 Protozoan Predators Inhibition of protozoan grazers in biofilms regulated by hapr (Matz et al. 2005)

19 Summary V. cholorae are more resistant to grazing pressure of flagellates and has distinct defense mechanisms Anti-protozoanal factor production QS regulated Protozoan grazing is a powerful ecological agent in control of environmental populations and identifying biofilm associated mechanisms that ensure the persistence and accumulation of bacterial populations in aquatic environments despite predatory pressure

20 Viral Predation Many phage carry surface enzymes that degrade d bacterial polysaccharides Numerous phages have been isolated which induce enzymes capable of degrading EPS of various gram-negative bacteria Allow access to infect host cells

21 Viral Predation E. coli cell concentrations in presence of T4 (Corbin et al. 2001)

22 Viral Predation Bacteiophage affect on P. aeruginosa biofilms (Hanlon et al. 2001)

23 Viral predation Reduction on exopolysaccharide viscosity (Hanlon et al. 2001)

24 Viral Predation Variability in susceptibility to viral predation (Hanlon et al. 2001)

25 Viral Predation Differential Phage release from biofilm and planktonic populations

26 Conclusion There is a drive to study predator-prey interactions i involved din biofilm ecology as a new means to discovery biological means for controlling biofilm formation However, there seems to be a common theme of resistance of biofilm bacteria when compared to planktonic bacteria Microcolony formation Toxicity production Unknowns