The 'Cheshire Cat' escape strategy in response to marine viruses
A novel defence strategy displayed in response to marine viruses by some of the most abundant unicellular organisms found in our oceans has recently been demonstrated by researchers in the Laboratoire Adaptation et diversité en milieu marin (CNRS, UPMC) working in collaboration with other European scientists. These results enable a clearer understanding of the origin of, and reasons for, sexual reproduction in eukaryotes(1). This study has been published in PNAS.
The researchers studied the impact of marine viruses on Emiliania huxleyi, one of the most abundant unicellular eukaryotes in oceans that significantly influences the carbon cycle and climates. In their diploid form, i.e. when they contain a pair of chromosomes (2N), Emiliania huxleyi produce mineral scales and form gigantic populations that are visible from space.
But when attacked by marine viruses, they transform into haploid cells which only contain a single chromosome (N). These new, non-calcifying, highly motile cells are totally invisible to viruses (and undetectable on satellite photos) so that the species can live in peace to await safer times.
These scientists have called this the "Cheshire Cat" strategy, in homage to Lewis Carroll's novel "Alice in Wonderland". In this book, the crafty and philosophical Cheshire Cat escapes being beheaded on the order of the Red Queen by rendering his body transparent. In the same way, by changing their form during the haploid phase, eukaryotes can evade biotic pressure and reinvent themselves within their own species.
Our ancestors, unicellular eukaryotes, appeared in oceans some one billion years ago and "invented" sexuality. These species are characterized by a life cycle where haploid individuals (carrying a single copy of the genome, like gametes(2)) unify to form diploid individuals that will subsequently generate haploid cells once again. During this eukaryote "double life", humans and other multicellular eukaryotes whose haploid gametes remain imprisoned within a diploid body, tend to be the exception.
Originally, and in most eukaryotes, haploid cells multiply in their environment to form independent populations. Sexuality has allowed eukaryotes to evade constant attacks by viruses so that they could evolve towards more complex, high-performance organisms, the ecological importance of which is still markedly underestimated.
Julien Guillaume | alfa
The most recent press releases about innovation >>>
Die letzten 5 Focus-News des innovations-reports im Überblick:
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...