Pico- Pico- Pico-zoa Picozoa

摘要

It's not often that a new phylum is described, but the vanishingly small eukaryotes that constitute the equivalent of dark matter of the plankton have now been named the Picozoa. These highly diverse organisms, previously known as (pico)biliphytes, are about 2 to 3μm in size and dominate aquatic ecosystems. Characterized by the pigment phycobilin and once thought to be photo-synthetic, they appear instead to tack plastids and seem to be hetero-trophic. Seenivasan et al. used a mitochondrial marker to isolate single (pico)billiphyte cells by fluorescence-activated cell sorting and established a first culture. The result was Picomonas judraskeda, a colloid feeder that moves through the North Sea by means of flagellae. This organism is a bipartite cell, joined at the mitochondrion, packaging all the feeding apparatus into one sac and the major organeiles with the motility apparatus in the other.