Amazing are the substantial actin cytoskeleton filaments (orange) in the cell bodies and cell protrusions, as well as the unique cell envelope (blue). Their cells are generally much larger and, at very first look, more intricate than the cells of bacteria and archaea. The hereditary material of eukaryotes, for example, is packaged in a cell nucleus and the cells likewise have a big number of other compartments.” The cells consist of round cell bodies with thin, often very long cell extensions. Standard cell biological processes such as cell department can also be studied in the future in order to shed light on the evolutionary origin of these systems in eukaryotes.
One of the presently most popular evolutionary theories presumes that eukaryotes (including plants, animals and fungis) emerged from the blend of an Asgard archaeon with a bacterium. Credit: © Florian Wollweber, ETH Zürich
A eukaryotic prehistoric cell is believed to have actually evolved from a close symbiosis in between archaea and bacteria about 2 billion years back. The very first images of Asgard cells were published in 2020 from enrichment cultures by a Japanese group.
Asgard archaea cultivated from marine sediments
Because of its growth to high cell densities, this representative can be studied particularly well. “It was really tricky and laborious to obtain this exceptionally sensitive organism in a stable culture in the lab,” reports Thiago Rodrigues-Oliveira, postdoc in the Archaea working group at the University of Vienna and one of the very first authors of the study.
Co-first author Rafael Ponce tasting marine sediment at the Seca Canal in Piran, Slovenia. Credit: © Thiago Rodrigues-Oliveira, Univ.
Wien Asgard archaea have an intricate cell shape with a substantial cytoskeleton The amazing success of the Viennese group to cultivate a highly enriched Asgard representative finally enabled for a more detailed examination of the cells by microscopy. The ETH researchers in Martin Pilhofers group used a modern cryo-electron microscope to take photos of shock-frozen cells. “This method enables a three-dimensional insight into the internal cellular structures,” explains Pilhofer.
Scanning electron micrograph of a Lokiarchaeum ossiferum cell showing the complicated and long cell protrusions. Credit: © Thiago Rodrigues-Oliveira, Univ.
Wien” The cells include round cell bodies with thin, sometimes really long cell extensions. These tentacle-like structures often even seem to connect various cell bodies with each other,” states Florian Wollweber, who invested months tracking down the cells under the microscope. The cells also include an extensive network of actin filaments believed to be distinct to eukaryotic cells. This suggests that substantial cytoskeletal structures emerged in archaea before the appearance of the first eukaryotes and fuels evolutionary theories around this essential and amazing event in the history of life.
In addition, the researchers can now utilize the new imaging approaches developed at ETH to investigate, for example, the close interactions in between Asgard archaea and their bacterial partners. Fundamental cell biological processes such as cell department can likewise be studied in the future in order to shed light on the evolutionary origin of these mechanisms in eukaryotes.
Referral: “Actin cytoskeleton and complex cell architecture in an Asgard archaeon” by Thiago Rodrigues-Oliveira, Florian Wollweber, Rafael I. Ponce-Toledo, Jingwei Xu, Simon K.-M. R. Rittmann, Andreas Klingl, Martin Pilhofer and Christa Schleper, 21 December 2022, Nature.DOI: 10.1038/ s41586-022-05550-y.
Cryo-electron tomography provided insight into the cellular structure of a newly cultured Asgard archaeon highlighted here. Amazing are the comprehensive actin cytoskeleton filaments (orange) in the cell bodies and cell protrusions, in addition to the special cell envelope (blue). Credit: © Margot Riggi, The Animation Lab, University of Utah
Researchers at the University of Vienna and ETH Zurich cultivate “missing out on link” microbe.
What resulted in the development of complicated organisms in the world? Its a considerable unanswered question in biology. Researchers from Christa Schlepers group at the University of Vienna and Martin Pilhofers team at ETH Zurich have actually taken an action towards resolving it. The researchers was successful in cultivating an unique archaeon and identifying it more precisely using microscopic approaches.
This member of the Asgard archaea displays special cellular characteristics and may represent an evolutionary “missing out on link” to more complicated life forms such as animals and plants. The study was just recently released in the journal Nature.
Their cells are generally much bigger and, at first glimpse, more complicated than the cells of bacteria and archaea. The genetic material of eukaryotes, for example, is packaged in a cell nucleus and the cells also have a large number of other compartments. Cell shape and transport within the eukaryotic cell are also based on a comprehensive cytoskeleton.
