Crenarchaeota

Sulfolobus, Sulfolobus infected with the virus STSV1. Scale = 1 microns.

The Crenarchaeota (from the Greek crenos, origin or source) are unicellular organisms and belong to the domain Archaea. Previously, the Crenarchaeota were held exclusively for extremophiles (ie, either ( extreme) thermophilic or psychrophilic or thermoacidophil ), but further investigation showed that the Crenarchaeota are the most common archaea in the ocean. This group is referred to as mesophilic marine group I Crenarchaeota.

Properties

Within the Crenarchaeota are found organisms that are adapted to extreme environmental conditions and can be found in areas with very high or very low temperatures. Many species live in the Arctic plankton, where they survive at temperatures often below 0 ° C. These psychrophilic however, have been only sporadically cultivated under laboratory conditions (see also Psychrophilie and Kryophile ). Another group within the Crenarchaeota lives under hyperthermic conditions, ie at temperatures of 80-110 ° C, Pyrolobus fumarii lives even at 113 ° C and survived even one hour autoclaving. Many of crenarchaeota such as Sulfolobus acidocaldarius and tolerate high concentrations of acid ( pH 1-2 ) and are thus thermoacidophil.

One of the best-characterized organisms of the Crenarchaeota is Sulfolobus solfataricus. Originally, this organism was isolated from sulphurous hot springs in Italy and is growing at 80 ° C and a pH of 2-4.

Since in their habitat often no organic substrate is present, many live on the fixation of sulfur, carbon dioxide or hydrogen. Others, however, can also metabolize organic material. When Kohlenstoffdioxidassimilation they use either the 3-Hydroxypropionat/4-Hydroxybutyratzyklus (eg Sulfolobus ) or the Dicarboxylat/4-Hydroxybutyratzyklus (eg Desulfurococcales or Thermoproteales ).

The representatives of the Crenarchaeota are the two virus families of Ligamenvirales as host, the Rudiviridae and Lipothrixviridae.