Cryptomonad
Rhodomonas salina
The Cryptophyceae ( AltGr. Κρύπτος secret and Φύκιον algae) are a class of single-celled, microscopic algae that are found in freshwater and seawater. The cryptophyceae move by means of two flagella through the water and can be reddish, bluish or brownish colored. Some cryptophyceae form thick-walled and spherical resting stages to survive unfavorable environmental conditions. As an ecologically important group of algae cryptophyceae serve many protists as food. As to the cryptophytes are colorless and photosynthetically active genera or species, there are botanical and zoological classifications. You can therefore also be referred to as zoological cryptomonads. From their evolutionary history and their resulting affinities ago they are systematically neither the animals nor the plants ( on the instantaneous state of knowledge, red algae, green algae and land plants are in the kingdom Plantae summarized ). The closest relatives of Cryptophyceae are best colorless and phagotroph living Katablepharidophyta.
Most cryptophyceae ( AltGr. Κρύπτο, " Crypto " "secret " and φύκιον " Phykion " alga ) with the exception of the genus Goniomonas have two nuclei of different evolutionary origin and were therefore of interest to evolutionary biologists. The different cell compartments here are nested inside each other like a matryoshka. The outermost compartment contains the actual cell nucleus and the cytoplasm in which are also the mitochondria. The next smaller so-called periplastidäre compartment contains the second greatly reduced cell nucleus ( = Nucleomorph ), and starch grains. The innermost compartment is the actual photosynthetic organelle, the plastid. Since mitochondria and plastids have their own genomes, a cryptophyceae cell contains a total of four genomes.
Explains the variety of genomes by a secondary endosymbiosis in which a phagotropher eukaryote took up a photosynthetic eukaryotes. Normally captured organisms are digested. In an endosymbiosis but the recorded cell is preserved and transformed over time into a dependent organelle to. However, only in the Chlorarachniophyceae and not related to them cryptophyceae the nucleus of the recorded alga was not lost.
The marine Cryptophycee Guillardia theta was selected as a model organism to sequence the genomes of Nucleomorph and plastid. Both genome sequencing revealed that the plastid of cryptophytes must originally have been a red alga. Further evidence for this theory are the starch synthesis and the 80S ribosomes in the periplastidären space ( the former cytoplasm of the captured red alga ) and the four envelope membranes surrounding the plastids. All plastids derived from a primary endosymbiosis ( the chloroplasts of green algae and land plants, the cyanelles the Glaucocystophyceen and rhodoplasts the red algae ) are deferred only two envelope membranes and not three or four ( = complex plastids ).
Nomenclature of Cryptophyceae
The systematic classification of cryptophyceae in different species has so far been mainly due to morphological features and pigmentation.
The combination of various features ( 1) structure of the Periplasten, (2) form the Zelleinstülpung, (3) position of the Nucleomorphs, (4) pigment type and (5 ) Structure of the scourge root apparatus arise the different genera.
The exploration of the relationships within the cryptophyceae using methods of molecular phylogenetic analysis ( = Creation of pedigrees based on DNA sequences), however, showed a much more complex picture. Cryptophyceae are probably dimorphic, meaning they can form two different cell types. Therefore, probably erroneously multiple two cell forms a genus of two distinct genera were maintained. Has been proven safe dimorphism in the genus Proteo Monas and Cryptomonas. Also a sticking plaster, a colorless plastid that has lost the ability to photosynthesize, is not a sure sign of a separate genus. The former genus Chilomonas proved to be a colorless Cryptomonas, exist by the addition, at least three different evolutionary lineages within Cryptomonas. The other genera of cryptophyceae probably require a revision to its scheme.
Genera of cryptophyceae after preliminary state of research: Chroomonas, Cryptomonas ( contains the formerly independent genera Campylomonas and Chilomonas ) Geminigera, Goniomonas, Guillardia, Hanusia, Hemiselmis, comma, Plagioselmis, Proteo Monas, Rhino Monas, Rhodomonas ( Pyrenomonas ) Teleaulax.