Present address: Department of Biology and Marine Biology, University of North Carolina, Wilmington, 601 South College Rd., Wilmington, NC 28403, USA.
THE ROLE OF NITRIC OXIDE IN DIATOM ADHESION IN RELATION TO SUBSTRATUM PROPERTIES1
Article first published online: 28 JUN 2008
© 2008 Phycological Society of America
Journal of Phycology
Volume 44, Issue 4, pages 967–976, August 2008
How to Cite
Thompson, S. E. M., Taylor, A. R., Brownlee, C., Callow, M. E. and Callow, J. A. (2008), THE ROLE OF NITRIC OXIDE IN DIATOM ADHESION IN RELATION TO SUBSTRATUM PROPERTIES. Journal of Phycology, 44: 967–976. doi: 10.1111/j.1529-8817.2008.00531.x
Received 5 September 2007. Accepted 18 December 2007.
- Issue published online: 30 JUL 2008
- Article first published online: 28 JUN 2008
- diatom adhesion;
- nitric oxide (NO);
- silicone elastomer
Adhesion of raphid diatoms to surfaces, mediated by the secretion of extracellular polymeric substances (EPS), is an important strategy for growth and survival. Diatom biofilms are also important in the context of biofouling. Diatoms exhibit selectivity in adhering to surfaces, but little is understood about how they perceive the properties of a substratum and translate that perception into altered adhesion properties. In this study, we demonstrate that Seminavis robusta Danielidis et D. G. Mann, like many other pennate diatoms, adheres more strongly to hydrophobic surfaces (such as silicone elastomer foul-release coatings) than to hydrophilic surfaces. To explore the cellular mechanisms that may underlie this selectivity, we tested the hypothesis that diatoms may perceive a hydrophilic surface as unconducive to adhesion through a form of stress response involving nitric oxide (NO) production. Single-cell imaging with the fluorescent indicator DAF-FM DA (4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate), revealed NO levels that were 4-fold higher in cells adhered to a hydrophilic surface (acid-washed glass) compared with a hydrophobic surface (polydimethylsiloxane elastomer, PDMSE). Elevated levels of NO caused by the addition of the NO donor S-nitroso-N-acetylpenicillamine (SNAP) did not affect growth, but cells showed reduced adhesion strength to both glass and PDMSE. Addition of the nitric oxide synthase inhibitor NG-monomethyl-l-arginine (NMMA) caused a small but significant increase in adhesion strength. Overall, the results suggest that NO acts as a signal of the wettability properties of substrata for Seminavis.