The fucose containing polymer (FCP) rich fraction of Ascophyllum nodosum (L.) Le Jol. protects Caenorhabditis elegans against Pseudomonas aeruginosa by triggering innate immune signaling pathways and suppression of pathogen virulence factors
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Saveetha Kandasamy1, Wajahatullah Khan2, Garima Kulshreshtha1, Franklin Evans3, Alan T. Critchley3, J. H. Fitton4, Damien N. Stringer4, Vicki-Anne Gardiner4 and Balakrishnan Prithiviraj1,* |
1Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, P.O. Box 550, Truro, NS B2B 5E3 Canada 2Basic Sciences Department, College of Science and Health Professions (COSHP), King Saud Bin Abdul Aziz University for Health Sciences (KSAU-HS), P.O. Box 22490, Riyadh 11426, Saudi Arabia 3Acadian Seaplants Limited, 30 Brown Avenue, Dartmouth, NS B3B 1X8, Canada 4Marinova Pty Ltd., 249, Kennedy Drive, Cambridge, Tasmania 7170, Australia
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ABSTRACT |
Brown algal extracts have long been used as feed supplements to promote health of farm animals. Here, we show new molecular insights in to the mechanism of action of a fucose containing polymer (FCP) rich fraction from the brown seaweed Ascophyllum nodosum using the Caenorhabditis elegans-Pseudomonas aeruginosa PA14 infection model. FCP enhanced survival of C. elegans against pathogen stress, correlated with up-regulation of key immune response genes such as: lipases, lysozyme (lys-1), saponin-like protein (spp-1), thaumatin-like protein (tlp-1), matridin SK domain protein (msk-1), antibacterial protein (abf-1), and lectin family protein (lfp). Further, FCP caused down regulation of P. aeruginosa quorum sensing genes: (lasI, lasR, rhlI, and rhlR), secreted virulence factors (lipase, proteases, and elastases) and toxic metabolites (pyocyanin, hydrogen cyanide, and siderophore). Biofilm formation and motility of pathogenic bacteria were also greatly attenuated when the culture media were treated with FCP. Interestingly, FCP failed to mitigate the pathogen stress in skn-1, daf-2, and pmk-1 mutants of C. elegans. This indicated that, FCP treatment acted on the regulation of fundamental innate immune pathways, which are conserved across the majority of organisms including humans. This study suggests the possible use of FCP, a seaweed component, as a functional food source for healthy living.
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Key words:
Ascophyllum nodosum; Caenorhabditis elegans; innate immunity; Pseudomonas aeruginosa; quorum sensing; virulence factors |
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