Extreme adaptations of species often cause such significant changes that their evolutionary history is difficult to reconstruct.
Zoologists at the University of Basel in Switzerland have now discovered a new parasite species that represents the missing link between fungi and an extreme group of parasites. Researches are now able to understand for the first time the evolution of these parasites, causing disease in humans and animals. The study has been published in the latest issue of the scientific journal Proceedings of the National Academy of Sciences (PNAS).
The water flea (Daphnia magna) serves as the host of the newly described parasite. The animal measures about 4mm in length. Dieter Eber, University of Basel
Parasites use their hosts to simplify their own lives. In order to do so, they evolved features that are so extreme that it is often impossible to compare them to other species. The evolution of these extreme adaptations is often impossible to reconstruct.
The research group lead by Prof. Dieter Ebert from the Department of Environmental Science at the University of Basel has now discovered the missing link that explains how this large group of extreme parasites, the microsporidia, has evolved. The team was supported in their efforts by scientists from Sweden and the U.S.
Microsporidia are a large group of extreme parasites that invade humans and animals and cost great damage for health care systems and in agriculture; over 1,200 species are known. They live inside their host's cells and have highly specialized features:
They are only able to reproduce inside the host's cells, they have the smallest known genome of all organisms with a cell nucleus (eukaryotes) and they posses no mitochondria of their own (the cell's power plant). In addition, they developed a specialized infection apparatus, the polar tube, which they use to insert themselves into the cells of their host. Due to their phenomenal high molecular evolution rate, genome analysis has so far been rather unsuccessful: Their great genomic divergence from all other known organisms further complicates the study of their evolutionary lineage.
Between fungi and parasite
The team of zoologists lead by Prof. Dieter Ebert has been studying the evolution of microsporidia for years. When they discovered a new parasite in water fleas a couple of years ago, they classified this undescribed species as a microsporidium, mostly because it possessed the unique harpoon-like infection apparatus (the polar-tube), one of the hallmarks of microsporidia.
The analysis of the entire genome had several surprises in store for them: The genome resembles more that of a fungi than a microsporidium and, in addition, also has a mitochondrial genome. The new species, now named Mitosporidium daphniae, thus represents the missing link between fungi and microsporidia.
With the help of scientists in Sweden and the U.S., the Basel researchers rewrote the evolutionary history of microsporidia. First, they showed that the new species derives from the ancestors of all known microsporidians and further, that the microsporidians derive from the most ancient fungi; thus its exact place in the tree of life has finally been found.
Further research confirms that the new species does in fact have a microsporidic, intracellular and parasitic lifestyle, but that its genome is rather atypical for a microsporidium. It resembles much more the genome of their fungal ancestors.
The scientists thus conclude that the microsporidia adopted intracellular parasitism first and only later changed their genome significantly. These genetic adaptations include the loss of mitochondria, as well as extreme metabolic and genomic simplification. “Our results are not only a milestone for the research on microsporidia, but they are also of great interest to the study of parasite-specific adaptations in evolution in general”, explains Ebert the findings.
Haag, K.L., James, T.Y., Pombert, J.-F., Larsson, R., Schaer, T.M.M., Refardt, D. & Ebert, D. 2014.
Evolution of a morphological novelty occurred before genome compaction in a lineage of extreme parasites
Proceedings of the National Academy of Sciences, USA, 13. Oktober 2014) www.pnas.org/cgi/doi/10.1073/pnas.1410442111
Prof. Dieter Ebert, Department for Environmental Science, Zoological Institute, phone: +41 (0)61 267 03 60, fax +41 (0)61 267 03 60, email: email@example.com
Olivia Poisson | Universität Basel
When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short
23.03.2017 | Institut für Pflanzenbiochemie
WPI team grows heart tissue on spinach leaves
23.03.2017 | Worcester Polytechnic Institute
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Life Sciences
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences