inhibition of bacterial quorum sensing by using marine algal extract as a anti-fouling agent

1. Seminar on……
Inhibition of Quoram Sensing and
Bacterial communication : Potential for
anti- fouling agents from marine algae
Presented by:
Pradip Hirapure
(JRF)
Discipline of Marine Biotechnology and Ecology
Central Salt and Marine Chemical Research Institute , Bhavnagar,
Gujarat

2. Quorum Sensing (QS)
- For many years bacteria were considered as a simple,
unicellular organism without a capacity to interact with
each other .
- In 1970’s above statement was found wrong due to the
discovery of bacterial communication.
- Cell- cell communication firstly discovered in Vibrio
fischeri
-In the free living state it do not gives luminescence but
at the high density of bacteria (threshold density) it gives
luminescence.
-Quorum sensing is a density dependent gene expression
phenomenon shows by bacteria
- Quorum sensing – intra cellular and intercellular
Nature review Microbiology (2008) Feb

4. Mechanism of Quorum Sensing
(xxx-HSL)
Binding Occurs only
at high AI
concentrations

5. 1. AHL start to diffuse 2. AHL diffused but con.of AHL is low
3. High AHL con. In surrounding
4. High AHL con. In bacterial cell
5. QS dependent gene express

6. Types of Auto-inducer Molecules
1: Acyl-homoserine lactones (AHLs): signaling molecules
used by many gram –ve bacteria, it synthesized by luxI family protiens
2: Autoinducer peptides (AIPs): signaling molecules used by
gram +ve bacteria,
3: Autoinducer-2 (AI-2): used by both gram –ve & gram + ve
bacteria ,chemically it is furanosyl borate diester. Synthesize by lux- s .
Schauder, S. and B. L. Bassler (2001). "The languages of bacteria."

8. Quorum sensing controlled processes
Bioluminescence
Biofilm formation
It occurs in various marine bacteria
such as Vibrio harveyi and Vibrio fischeri.
Takes place at high cell density.
It is compact mass of differentiated microbial cells, enclosed
in a matrix of polysaccharides. Biofilm resident bacteria
are antibiotic resistant. Quorum sensing is responsible for
development of thick layered biofilm.
8
QS upregulates virulence Virulence gene expression gene expression
Sporulation
Competence
QS upregulates spore-forming genes in
Bacillus subtilis
It is ability to take up exogenous DNA
QS Increase competence in Bacillus subtilis

9. Bioluminescence
Virulence factor antibiotic
degrading enzymes production
QS-controlled phenotypes

10. What is Biofouling
- Biofouling is one of the more serious problems created by biofilm-forming
bacterial species (Dalton and March 1998).
- It shows financial implication to the marine engineering construction like
ship , marine pipeline , heat exchanger pipe ,hydroelectric pipeline etc.
- Solid surfaces, when exposed to sea- water, undergo a series of changes
leading to the generation of a complex layer mainly consisting of microbial
,slimes, diatoms, barnacles, tunicates, bryozoans and spores of marine
algae. This phenomenon is known as biofouling.
- These fouling organisms can cause extensive damage to commercial
important marine structures
- Worldwide expenditure on antifouling US 6.5 billion $ / year.
- Currently used TBT as a antifouling agent
(Rasmussen and Østgaard 2003 Bhosale et al. 2002; Elvers and Lappin-Scott 2000; John et al. 1999;).

11. 5. dispersion
PLoS Biology (2007) Nov
1. Initial
attachment
2. Irreversible
attachment 3. Maturation I
4. maturation II

12. Goal of my research
Develop Novel, Non-toxic Natural
Quorum Sensing Inhibitor
as a Antifoulants

13. Objectives of my work
1.To screen various macro algae's across the
Indian coast for quorum sensing inhibitor
2. Identification and characterization of novel
quorum sensing inhibitor
3. Molecular phylogenic characterization marine
algae containing quorum sensing inhibitor
4.Transcript profiling of the test organisms
using the quorum sensing inhibitor.

14. Strategies for quorum sensing inhibition
3 strategies can be applied
Targeting AHL signal
Targeting Targeting signal
the signal
14
dissemination
receptor
generation
Signal precursor
Signal
Signal receptor
Signal precursor Signal precursor
Signal Signal
Signal receptor Signal receptor
X
X
X

15. Collection of marine algae
Preparation of algal extracts
Screening of algal extracts for QSI
Identification of QSI compounds
HPLC GC/MS LC/MS
Characterization of bioactive substances

16. Bioassay by using Biosensors
GFP Constructs ( Biosensor)
1. P.putida F17:
ME 12
2. E.coli PJB89:
MR 3. S. liquefacience MG44:
AHL- C12
TE-12
TR
AHL + LUX -R

17. References
• Thomas B. Rasmussen Microbiology (2006), 152, 895–904
• Abarzua, S. and Jacobowsky, S., Biotechnological investigations for the
prevention of biofouling. 1. Biological and biochemical principles for the
prevention of biofouling. Mar. Ecol. Prog. Ser.,
1995, 123, 301–312.
- Sheetal Raina*, Daniela De VizioBiotechnol. Appl. BBiioocchheemm.. ((22000099)) 5544,, 6655––8844
• Miller, M. B. and Bassler, B. L. (2001) Annu. Rev. Microbiol.55, 165–199
• Bassler, B. L. (1999) Curr. Opin. Microbiol. 2, 582–587
• Kleerebezem, M., Quadri, L. E., Kuipers, O. P. and
• de Vos, W. M. (1997) Mol. Microbiol. 895–904
• Olsen, J. A., Severinsen, R., Rasmussen, T. B., Hentzer, M., Givskov,
M. Nielsen, J. (2002).

18. MR
ME 12
AHL- C12
TE-12
TR