Hatena arenicola

Hatena arenicola is a unicellular eukaryote meeresbewohnender, which enters into a community with a green alga of the genus Nephroselmis. The species was until now found only at a Japanese sand beach, what their designation indicates ( Hatena, Japaneseはてな, dt The Mysterious and arenicola, Latin sand -dwelling ).

Description

Hatena arenicola is flattened along the dorsiventral axis, ovoid in ventral view, 30-40 microns long and 15-20 microns wide. Subapical, ie below the peak, a 3-4 microns long and is about 2 microns wide furrow, from which the long front and short rear scourge escape. Two rows of light microscopy easily recognizable Ejectisomen are the rear end of the furrow. The large nucleus is located centrally in the rear areas of the cell. Most of the remaining cytoplasm is occupied by the endosymbiont, which is mainly fulfilled by his plastid. Compared to free-living cells Nephroselmis the symbionts are magnified up to ten times, and have a reduced cytoplasm and several pyrenoids on. They also have a complex built eyespot. When caught in the open cells of the symbiont missing rarely, some symbionts, however, are not fully developed, which may be explained through the life cycle.

Life cycle

In the division of the nucleus of the host cell migrates first to the tip between the point of insertion of the flagella and eyespot of the symbiont. The symbiote then withdraws into the left half of the cell. After the formation of a second Flagellenpaars share nucleus and cell, so that a green daughter cell with symbiont and a colorless daughter cells arise. The colorless cells form from a complex cell mouth and likely to live up to the start of a new symbiont by phagocytosis predatory. Because the exact strain of the symbiont is not known, the complete cycle in the laboratory has not yet been observed.

Could be an evolutionary standpoint is this symbiosis of interest, since there is a shift from heterotrophy to autotrophy and the inclusion of the symbionts by Hatena arenicola as predators of the recording of organelles in other eukaryotes, as described in the endosymbiont theory correspond.