Inhibition of algal spore germination by the marine bacterium Pseudoalteromonas tunicata

A collection of 56 bacteria isolated from different surfaces in the marine environment were assayed for their effects on the germination of spores fro m the common green alga Ulva lactuea. Thirteen bacterial isolates were show n to inhibit spore germination. Of these bacteria, Pseudoalteromonas tunica ta displayed the most pronounced effects against algal spores. Further char acterisation of the anti-algal activity of P. tunicata was performed and it was found that this bacterium produces an extracellular component with spe cific activity toward algal spores that is heat-sensitive, polar and betwee n 3 and 10 kDa in size. This biologically active compound was also found to prevent the germination of spores from the red alga Polysiphonia sp, and, given the widespread occurrence of P. tunicata in a range of marine habitat s, this may suggest that it is effective against a variety of marine algae. (C) 2001 Federation of European Microbiological Societies. Published by El sevier Science B.V. All rights reserved.