Survival of the fattest

Mike Allen and Willie Wilson examine their work on the coccolithoviruses, some of the most abundant and widespread organisms in the oceans. These photosynthetic microscopic algae form the base of the oceans' food chain and play a major role in the global carbon cycle, drawing down vast volumes of carbon dioxide from the atmosphere. Analysis of these viruses' genetic make-up revealed large double-stranded DNA viruses with genomes of about 410,000 base pairs. These viruses belong to the newly-created genus Coccolithovirus. Emiliania huxleyi seems to use an intriguing strategy to avoid viral infection. It switches to an entirely different state in its life cycle so that an attacking virus can not get a foothold. When the virus infects a coccolithophore, it quickly turns on this sphingolipid pathway and expresses it to a level two orders of magnitude greater than the normal Emiliania huxleyi pathway.