Quorum Sensing Inhibitionof Vibrio alginolyticus from Caulerpa lentillifera

(Lato) on Pseudomonas aeruginosa

Arbo, Ma. Adelle Gia T.Arteta, Allen O.

Belmonte, Pauline Marie C.

What is Quorum Sensing?

accumulation of signaling molecules enabling a single cell to sense the population density (Bhattacharya et al, 2008, pp. 30)

production and release of chemical signal molecules called autoinducers to coordinate gene expression

significant in biofilm formation and virulence of some microorganisms

an opportunistic bacterium that uses

quorum sensing in the formation of biofilms,

swarming motility, expolysaccharide

production, and cell aggregation.

(Bhattacharyya et al, 2008, pp. 30-33)

Pseudomonas aeruginosa

Figure 1. Pseudomonas aeruginosa(http://textbookofbacteriology.net/

pseudomonas.html)

Related Studies Givskov, Michael et al (2006)

-quorum sensing signaling systems of pathogens were used as central regulators for the expression of virulence factors

-Quorum sensing inhibitors - compounds are capable of reducing virulence and be used as treatment

Joint, Ian et al (2007) -the green seaweed Ulva has been shown to detect N-acylhomoserine lactones (AHLs)

Seaweeds suitable substrate

for epibiotic organisms because it releases a large amount of carbon into the surrounding environment

Figure 2. Seaweeds

http://davaoorientalinvest.com/main/?page_id=121

Caulerpa lentillifera• abundant in the

Philippines and cultivated as food and sold fresh and

salted

Figure 3. Caulerpa lentillifera

http://www.mesa.edu.au/marine_algae/gallery.asp)

Vibrio alginolyticus

a gram negative bacterium usually isolated from the surface of marine organisms such as seaweeds and stony corals

Some Vibrio species have quorum sensing inhibiting ability

Statement of the Problem

Main Problem:

Is Vibrio alginolyticus from seaweed, Caulerpa

lentillifera capable of inhibiting the quorum

sensing of Pseudomonas aeruginosa?

1. Are there zones of inhibition exhibited by Vibrio alginolyticus on Chromobacterium violaceum after agar overlay technique?

2. Are there zones of inhibition exhibited by Vibrio alginolyticus on Pseudomonas aeruginosa after agar overlay technique?

Specific Problems:

Significance of the Study

seaweed farmersantimicrobial agents economyPharmacology

Scope and Limitation

seaweed Caulerpa lentillifera use of indicator Chromobacterium violaceum 12472 use of lb broth

LimitationScope Quorum sensing inhibition assay antibacterial assay time observation time

Research Design

R X1 O1R X2 O2

Where:O1 & O2 = posttest observationX1 = quorum sensing inhibition assayX2 = antibacterial assay

Research Paradigm

Agar overlay of Pseudomonas aeruginosa

and Chromobacterium violaceum

Quorum sensing systems of

Pseudomonas aeruginosa;

Chromobacteriumviolaceum 12472, Vibrio

alginolyticus

Zones of inhibition of Pseudomonas

aeruginosa and

Chromobacterium violaceum 12472

Signaling molecules and growth conditions of the

bacteria

Independent Variables

Dependent Variables

Extraneous Variables

Linking Variables

Figure 4. Research Paradigm

Treatment/ General Procedure

Isolation of Vibrio alginolyticus

Figure 5. Taking samples of bacteria from Caulerpa

lentillifera

Figure 6. Agar plate inoculated with bacteria from Caulerpa

lentillifera

A. Quorum Sensing Inhibition AssayPreparation of Marine

agar plates and lb broth

Inoculation of Chromobacterium

violaceum 12472 and Vibrio alginolyticus on lb broth and marine agar,

respectively

24- Hour incubation

Overlay of lb broth on the marine agar plates inoculated

with Vibrio alginolyticus

24- Hour incubation

Observation and Data Gathering

Figure 7. Plate inoculated with C. violaceum and P. aeruginosa Figure 8. Inoculating lb

broth with C. violaceum

Figure 9. Test tube inoculated with C. violaceum

Figure 10. Overlay of lb broth on marine agar

after 24 hours.

Observation and Data Gathering

Preparation of marine agar plates and trypticase soy broth

Inoculation of Vibrio alginolyticus on marine agar

and of Pseudomonas aeruginosa on trypticase soy

agar

24-hour incubation

Overlay of trypticase soy on marine agar plates

24-hour incubation

B. Agar Overlay of Pseudomonas aeruginosa

Figure 11. TSB inoculated with Pseudomonas

aeruginosa

Figure 12 Marine agar inoculated with Vibrio

alginolyticus

Figure 13. Agar overlay of Pseudomonas aeruginosa

Figure 14. Overlay of TSB on marine agar after 24 hours

Results and DiscussionThere was no noticeable zone of inhibition

induced by Vibrio alginolyticus on both Chromobacterium violaceum and

Pseudomonas aeruginosa.

Figure 15. Marine agar plate of Vibrio alginolyticus after agar overlay of Chromobacterium

violaceum

Figure 16. Marine agar plate of Vibrio alginolyticus after agar overlay of Chromobacterium

violaceum

no verification that organisms had quorum sensing at that time mutations of organisms population of organisms conditions of bacterial growth

Further understanding of quorum sensing isolate more organisms exploit other techniques

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