Caffeine as a novel quorum sensing inhibitor / Siti Nur Maisarah Norizan
Quorum sensing (QS) is a system used by bacteria to control the gene expression in response to cell density. QS involves in the regulation of variety bacterial physiological functions such as biofilm formation, pyocyanin production and swarming which has been recorded to contribute to bacterial p...
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| Format: | Thesis |
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2017
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| Online Access: | http://studentsrepo.um.edu.my/9177/ http://studentsrepo.um.edu.my/9177/1/Siti_Nur_Maisarah_Norizan.pdf http://studentsrepo.um.edu.my/9177/5/Siti_Nur_Maisarah_Norizan_%E2%80%93_Dissertation.pdf |
| Summary: | Quorum sensing (QS) is a system used by bacteria to control the gene expression in
response to cell density. QS involves in the regulation of variety bacterial physiological
functions such as biofilm formation, pyocyanin production and swarming which has
been recorded to contribute to bacterial pathogenesis. Therefore, QS would be an
interesting target to attenuate pathogens for treating bacterial pathogenicity and
infections. In this work, the anti-QS activity of caffeine; a natural occurring alkaloid
found at varying quantities in seeds, leaves and fruits of some plants were tested against
Chromobacterium violaceum CV026 and Pseudomonas aeruginosa PA01.
Quantification assay on the violacein produced by C. violaceum CV026 showed that
caffeine inhibited violacein synthesis in concentration dependent manner. In agreement
to that, qualitative studies of C. violaceum CV026 showed the extent of violacein
reduction is approximately 68% for caffeine applied at the concentration of 0.3mg/mL.
Subsequently, this study also showed that caffeine inhibited swarming motility of P.
aeruginosa PA01 as observed by the reduction of P. aeruginosa PA01 migration
distance from the spot-inoculated centre on the swarming agar. In addition, caffeine also
inhibited P. aeruginosa PA01 pyocyanin production. Qualitative study conducted on P.
aeruginosa PA01 has confirmed that P. aeruginosa PA01 pyocyanin production was
reduced up to 77% when treated with caffeine at 0.3mg/mL. To the best of our
knowledge, this is the first documentation providing evidence on the presence of
caffeine anti-quorum sensing activity. This study will allow caffeine to be explored as
an alternative for anti-infective drug in future. |
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