virus is the largest and most complex of the seas and called Crova. I have just identified the microbiologist Curtis Suttle and his team University of British Columbia (Canada) in a study published in the Proceedings of the National Academy of Sciences. It is not clear Crova role in the ecosystem, but it could be very important, as is the number one enemy of the protozoan flagellate Cafeteria roenbergensis (hence the name). This protozoan is in fact among the most active and abundant predators of the Earth (it feeds on bacteria), and is a major organ for nutrient cycling and some elements, particularly that of carbon.
Crova was discovered in the early nineties by Canadian scientists off the coast of Texas (Atlantic Ocean). After twenty years we know that this is the second largest virus ever discovered. Its genome is in fact made up of 730 000 pairs of nucleotide bases (the building blocks of DNA and RNA), second only to that of mimivirus Acanthamoeba polyphaga (1.2 million bases), found in freshwater ecosystems.
For biologists, viruses are difficult to classify entities. To reproduce, in fact, need the proteins synthesized within host cells, a characteristic that excludes them from the category of beings called "living." But the new discovery puts scientists in difficulty. "Viruses are considered simple organisms because they carry a small number of genes," said Curtis. "But the genetic machinery is found in Crova equal to that which characterized the cells of complex organisms. And there is no doubt that the newcomer is only one of many, still unknown, but essential, giant viruses that inhabit the seas. "
picture, two protozoan flagellates Cafeteria roenbergensis
References: PNAS doi: 10.1073/pnas.1007615107
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