Hostname: page-component-848d4c4894-p2v8j Total loading time: 0.001 Render date: 2024-05-24T01:45:07.523Z Has data issue: false hasContentIssue false

Differential antibacterial activities of fusiform and oval morphotypes of Phaeodactylum tricornutum (Bacillariophyceae)

Published online by Cambridge University Press:  10 February 2010

Andrew P. Desbois
Scottish Oceans Institute, Gatty Marine Laboratory, School of Biology, University of St Andrews, Fife, Scotland, UK
Mike Walton
Scottish Oceans Institute, Gatty Marine Laboratory, School of Biology, University of St Andrews, Fife, Scotland, UK
Valerie J. Smith*
Scottish Oceans Institute, Gatty Marine Laboratory, School of Biology, University of St Andrews, Fife, Scotland, UK
Correspondence should be addressed to: V.J. Smith, Scottish Oceans Institute, Gatty Marine Laboratory, School of Biology, University of St Andrews, Fife, Scotland, UK email:


The diatom, Phaeodactylum tricornutum is a common inhabitant of inshore waters and can exist in different morphotypes that are thought to be adapted for survival in different habitats. Despite this diatom being widely used for physiological and genetic studies of microalgae, little is known about biochemical or physiological differences between the cell morphotypes. The present study was aimed at comparing differences in the antibacterial properties of the fusiform and oval morphotypes, the dominant cell types found in laboratory cultures of most strains of P. tricornutum. In cultures differing in proportions of fusiform and oval cells, there is a significant and positive correlation between the proportion of cells in the fusiform morphotype and the antibacterial activity of cell extracts. Extracts prepared from cultures enriched for fusiform cells (~76%) show greater antibacterial activity against the Gram-positive bacterium, Staphylococcus aureus, than those prepared from pure (100%) oval cultures. Thus fusiform cells contain greater antibacterial activity per cell compared to the ovals. Gas–liquid chromatographic analyses of the extracts reveal that those from enriched fusiform populations contain significantly greater levels of the free fatty acids, eicosapentaenoic acid (EPA), hexadecatrienoic acid (HTA) and palmitoleic acid (PA) than the pure oval cell cultures. These free fatty acids from P. tricornutum have been previously shown by us to have potent antibacterial activity against S. aureus. Free fatty acids, released from damaged microalgal cells, defend the microalgal population against grazing predators but, here, we suggest that these free fatty acids could also act against pathogenic bacteria in the vicinity of the algae. As cell extracts from the fusiform cells contain greater quantities of these fatty acids, fusiform cells may have greater potential than the ovals for this type of protection.

Research Article
Copyright © Marine Biological Association of the United Kingdom 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)



Bartual, A., Angel Gálvez, J. and Ojeda, F. (2008) Phenotypic response of the diatom Phaeodactylum tricornutum Bohlin to experimental changes in the inorganic carbon system. Botanica Marina 51, 350359.CrossRefGoogle Scholar
Borowitzka, M.A., Chiappino, M.L. and Volcani, B.E. (1977) Ultrastructure of a chain-forming diatom Phaeodactylum tricornutum. Journal of Phycology 13, 162170.Google Scholar
Borowitzka, M.A. and Volcani, B.E. (1978) The polymorphic diatom Phaeodactylum tricornutum: ultrastructure of its morphotypes. Journal of Phycology 14, 1021.CrossRefGoogle Scholar
Bowler, C. et al. (2008) The Phaeodactylum genome reveals the evolutionary history of diatom genomes. Nature 456, 239244.CrossRefGoogle ScholarPubMed
Cole, J.J. (1982) Interactions between bacteria and algae in aquatic ecosystems. Annual Review of Ecological Systems 13, 291314.CrossRefGoogle Scholar
Coughlan, J. (1962) Chain formation by Phaeodactylum. Nature 195, 831832.CrossRefGoogle Scholar
Darley, W.M. (1968) Deoxyribonucleic acid content of the three cell types of Phaeodactylum tricornutum Bohlin. Journal of Phycology 4, 219220.CrossRefGoogle ScholarPubMed
De Martino, A., Meichenin, A., Shi, J., Pan, K. and Bowler, C. (2007) Genetic and phenotypic characterization of Phaeodactylum tricornutum (Bacillariophyceae) accessions. Journal of Phycology 43, 9921009.CrossRefGoogle Scholar
Desbois, A.P., Mearns-Spragg, A. and Smith, V.J. (2009) A fatty acid from the diatom Phaeodactylum tricornutum is antibacterial against diverse bacteria including multi-resistant Staphylococcus aureus (MRSA). Marine Biotechnology 11, 4552.CrossRefGoogle ScholarPubMed
Desbois, A.P., Yan, L., Lebl, T. and Smith, V.J. (2008) Isolation and structural characterisation of two antibacterial free fatty acids from the marine diatom, Phaeodactylum tricornutum. Applied Microbiology and Biotechnology 81, 755764.CrossRefGoogle ScholarPubMed
Duff, D.C.B., Bruce, D.L. and Antia, N.J. (1966) The antibacterial activity of marine planktonic algae. Canadian Journal of Microbiology 12, 877884.CrossRefGoogle ScholarPubMed
Francius, G., Tesson, B., Dague, E., Martin-Jézéquel, V. and Dufrêne, Y.F. (2008) Nanostructure and nanomechanics of live Phaeodactylum tricornutum morphotypes. Environmental Microbiology 10, 13441356.CrossRefGoogle ScholarPubMed
Gutenbrunner, S.A., Thalhamer, J. and Schmid, A.-M.M. (1994) Proteinaceous and immunochemical distinctions between the oval and fusiform morphotypes of Phaeodactylum tricornutum (Bacillariophyceae). Journal of Phycology 30, 129136.CrossRefGoogle Scholar
Hamm, C.E., Merkel, R., Springer, O., Jurkojc, P., Maier, C., Prechtel, K. and Smetacek, V. (2003) Architecture and material properties of diatom shells provide effective mechanical protection. Nature 421, 841843.CrossRefGoogle ScholarPubMed
Harrison, P.J., Waters, R.E. and Taylor, F.J.R. (1980) A broad spectrum artificial seawater medium for coastal and open ocean phytoplankton. Journal of Phycology 16, 2835.Google Scholar
Hayward, J. (1968) Studies on the growth of Phaeodactylum tricornutum. Journal of the Marine Biological Association of the United Kingdom 48, 657666.CrossRefGoogle Scholar
Imai, I., Ishida, Y. and Hata, Y. (1993) Killing of marine phytoplankton by a gliding bacterium Cytophaga sp., isolated from the coastal Sea of Japan. Marine Biology 116, 527532.CrossRefGoogle Scholar
Iwasa, K. and Shimizu, A. (1972) Motility of the diatom, Phaeodactylum tricornutum. Experimental Cell Research 74, 552558.CrossRefGoogle ScholarPubMed
Johansen, J.R. (1991) Morphological variability and cell wall composition of Phaeodactylum tricornutum (Bacillariophyceae). Great Basin Naturalist 51, 310315.Google Scholar
Jüttner, F. (2001) Liberation of 5,8,11,14,17-eicosapentaenoic acid and other polyunsaturated fatty acids from lipids as a grazer defense reaction in epilithic diatom biofilms. Journal of Phycology 37, 744755.CrossRefGoogle Scholar
Kellam, S.J. and Walker, J.M. (1989) Antibacterial activity from marine microalgae in laboratory culture. British Phycological Journal 24, 191194.CrossRefGoogle Scholar
Lehrer, R.I., Rosenman, M., Harwig, S.S.S.L., Jackson, R. and Eisenhauer, P. (1991) Ultrasensitive assays for endogenous antimicrobial polypeptides. Journal of Immunological Methods 137, 167173.CrossRefGoogle ScholarPubMed
Lewin, J.C., Lewin, R.A. and Philpott, D.E. (1958) Observations on Phaeodactylum tricornutum. Journal of General Microbiology 18, 418426.CrossRefGoogle ScholarPubMed
Marsot, P. and Houle, L. (1989) Excrétion cellulaire et morphogénèse de Phaeodactylum tricornutum (Bacillariophyceae). Botanica Marina 32, 355367.CrossRefGoogle Scholar
Mayali, X. and Azam, F. (2004) Algicidal bacteria in the sea and their impact on algal blooms. Journal of Eukaryotic Microbiology 51, 139144.CrossRefGoogle ScholarPubMed
Morales, E.A., Trainor, F.R. and Schlichting, C.D. (2002) Evolutionary and ecological implications of plastic responses of algae. Constancea 83. Last accessed 4 November 2008. []Google Scholar
Pohnert, G. (2002) Phospholipase A2 activity triggers the wound-activated chemical defense in the diatom Thalassiosira rotula. Plant Physiology 129, 103111.CrossRefGoogle ScholarPubMed
Reynolds, C.S. (2007) Variability in the provision and function of mucilage in phytoplankton: facultative responses to the environment. Hydrobiologia 578, 3745.CrossRefGoogle Scholar
Tesson, B., Gaillard, C. and Martin-Jézéquel, V. (2009) Insights into the polymorphism of the diatom Phaeodactylum tricornutum Bohlin. Botanica Marina 52, 104116.CrossRefGoogle Scholar
Wilson, D.P. (1946) The triradiate and other forms of Nitzschia closterium (Ehrenberg) Wm. Smith, forma minutissima of Allen and Nelson. Journal of the Marine Biological Association of the United Kingdom 26, 235270.CrossRefGoogle Scholar