Fungus or appeared 1 billion years ago May 28, 2019 Source: Chinese Journal of Science and Technology WASHINGTON tiny fossils excavated from the remote Canadian Arctic, the first known time the appearance of fungus may be traced back to about 10 billion years ago - the early years than previously expected 500 million scientists. A paper published in the May 22 issue of Nature describes these primitive fungi – they are very small, but the structure is surprisingly complex and has a filamentous structure. Further chemical analysis indicates that these fossils contain chitin, which is usually a chemical found in the fungal cell wall. If this analysis is well established, it will reshape scientists' understanding of the evolutionary process of fungi and whether fungi promote the migration of plants to the land. But some researchers are still not sure if this discovery is really a fungus. “In my opinion, there seems to be reason to believe that this is true,†said Mary Berbee, a mycologist at the University of British Columbia in Vancouver, Canada. “But more data will be very helpful.†Corentin Loron, a paleontologist at the University of Liege, Belgium, and his colleagues discovered these fossils when they visited a region in the Canadian Arctic called "Grass Bay Structure." Researchers had to take a helicopter to the location - it is located near the striking cliffs of the area. Loman's consultant and paleontologist Emmanuelle Javaux at the University of Liège said that the fossils were very well preserved because the rocks there were not affected by the heat and pressure. The research team painstakingly cut these fossils into thin sheets that could be analyzed under an electron microscope. The final image shows the branched filaments ending in the sphere. At the same time, the filaments are also divided into segments by the membrane (cell walls found in some modern fungi). These fossils were found in rocks with a history of 1 billion years, and the presence of chitin in fossils further convinced the researchers that they were fungi that were preserved after they died 1 billion years ago. The team named the fungus Aurasphaira giraldae. But the researchers' interpretation of the chemical analysis of this discovery confuses Sylvain Bernard, a geochemist at the Institute of Mineralogy, Materials Physics and Cosmology in Paris, France. Bernard said that the presence of many organic molecules may produce similar results, and the results of related chemical analysis have also found that molecules are usually absent in chitin. “These data do not prove that these microfossils originally contained chitin.†Loron countered that these samples may contain chitin and other organic compounds. He also pointed out that these fossil surfaces have chemical signals unique to chitin and chitin-like fibers. "Our findings are most consistent with chitin," Loron said. According to Javaux, the team used the rate of accumulation of DNA (DNA) changes in fungi to calculate their first appearance, and the results were consistent with molecular findings. These "molecular clock" analyses have traced the origin of this fungus to about 1 billion years ago. But Christine Strullu-Derrien, a paleontologist at the Natural History Museum in London, said that previous molecular analysis showed that the fungus that lived a billion years ago was a simple single-celled creature that did not have the more complex filamentous structure seen in fossils. . Despite this, Strullu-Derrien hopes that further research will confirm the inclusion of chitin in these fossils. She said: "I would like to believe that this is an important discovery in the world - if it is really a fungus." A fungus is a eukaryote. The most common fungi are all kinds of mites, including mold and yeast. More than 70,000 species of fungi have been discovered. Fungi are self-contained and distinct from plants, animals and bacteria. The biggest difference between fungi and the other three organisms is that the cells of the fungus contain cell walls with chitin as the main component, and the cell walls of the plants are mainly composed of cellulose . (Zhao Xixi) Related paper information: DOI: 10.1038/d41586-019-01629-1 X Ray Lead Shield,Medical X Ray Lead Shield,X-Ray Shield Protection Lead,X - Ray Shielded Lead Longkou Kangxie Medical Instrument Co., Ltd , https://www.kangxiemedical.com
Fungus or appeared 1 billion years ago
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