3. The V. fischeri Autoinducer
N-(b-ketocaproyl)-L-homoserine lactone

4. Quorum Sensing
LuxI
LuxR
LuxR
target gene

5. Acyl-Homoserine Lactone Autoinducers

6. LuxI-LuxR Quorum Sensing Systems
V. fischeri
P.aeruginosa
A. tumefaciens
E. carotovora
Density dependent luminescence
Virulence factors
Conjugal transfer of Ti plasmid
Antibiotic synthesis

7. Quorum Sensing in V. harveyi
AI-2
LuxQ
LuxP H D H D
HTH
LuxU
LuxO H D
LuxN
AI-1
LuxR
LuxCDABE

8. Quorum Sensing in E. coli and Salmonella

9. Bacteria That Contain luxS
Klebsiella pneumoniae
Lactococcus lactis
Leuconostoc oenos
Listeria monocytogenes
Neisseria gonorrhoeae
Neisseria meningitidis
Pasteurella multocida
Porphyromonas gingivalis
Proteus mirabilis
Salmonella paratyphi
Salmonella typhi
Salmonella typhimurium
Bacillus anthracis
Bacillus halodurans
Bacillus subtilis
Borrelia burgdorferi
Campylobacter jejuni
Clostridium acetobolyticum
Clostridium difficile
Clostridium perfringens
Deinococcus radiodurans
Escherichia coli
Enterococcus faecalis
Haemophilus influenzae
Helicobacter pylori
Shewanella putrefaciens
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus gordonii
Streptococcus mutans
Streptococcus pneumoniae
Streptococcus pyogenes
Vibrio anguillarum
Vibrio cholerae
Vibrio harveyi
Vibrio vulnificus
Yersinia pestis

10. pfs
metK
luxS

12. MetK
Pfs
Page 544

13. SAM Utilization Met SAM SAH MTA SRH MTR 4,5-Dihydroxy-
2,3-pentanedione
+ HC ?
MetK
Pfs

14. SAM Utilization Met MetK SAM SAH MTA Pfs Pfs SRH MTR LuxS?
4,5-Dihydroxy-
2,3-pentanedione
+ HC ?

15. SAM Utilization
Met
MetK
SAM
SAH
MTA
Pfs
Pfs
SRH
MTR
LuxS
AI-2 + HC ?

16. The LuxS Reaction
4,5-Dihydroxy-
2,3-pentanedione
SRH +
Homocysteine

17. AI-2 Could be a Furanone
MHF
DMHF HF
DHCP

18. Quorum Sensing in V. harveyi
AI-2
LuxQ
LuxP H D H D
HTH
LuxU
LuxO H D
LuxN
AI-1
LuxCDABE
LuxR

19. Holo-LuxP

23. Boron is ubiquitous in the biosphere
Sea water 0.4 mM (primarily boric acid)
L.A. tap water 40 μM
Soils ppm
Marine plants 120 ppm
Land plants 50 ppm
Marine animals ppm
Land animals 0.5 ppm
Boron is required by a number of organisms,
but for poorly characterized reasons
Vascular plants cell wall? pollination?
Diatoms
Cyanobacteria heterocyst formation
Zebrafish embryogenesis

24. 11B NMR
holo-LuxP
filtered
apo-LuxP

25. Synthesis of AI-2

26. Boric Acid Induces Lux in V. harveyi

27. Synthesis of AI-2

28. Targets of AI-2 Vibrio harveyi Bioluminescence, Biofilms
Vibrio cholerae Virulence, Biofilms
Salmonella typhimurium ABC transporter
Salmonella typhi Biofilms
Escherichia coli O157:H7 Type III Secretion (virulence)
Porphyromonas gingivalis Hemin acquisition genes, virulence factors
Shigella flexneri VirB (virulence factor)
Streptococcus pyogenes Secreted protease
Actinobacillus actinomycetemcomitans Periodontal virulence, Mixed-species biofilms
Photorhabdus luminescens Antibiotic production
Neisseria meningitidis Virulence/bacteremia
Borrelia burgdorferi Virulence
Clostridium perfringens Virulence
Campylobacter jejuni Motility
Microarrays
Escherichia coli K ~300 genes
Escherichia coli O157:H7 ~400 genes
Vibrio cholerae El Tor ~70 genes (virulence regulon)

29. Biosynthesis of AI-1 and AI-2
Met
MetK
LuxI
SAM
LuxLM
AI-1
SAH
MTA
Pfs
Pfs
SRH
MTR
LuxS
AI-2 + HC ?

30. Quorum Sensing in V. harveyi
AI-2
LuxQ
LuxP H D H D
HTH
LuxU
LuxO H D
LuxN
AI-1
LuxCDABE
LuxR