We already have good preliminary data for...

Science (December 2, 2010)

University of Massachusetts Amherst microbiologists Derek Lovley, Zarath Summers and his colleagues report in the December 2 issue of Science >> << that they have discovered a new cooperative behavior in anaerobic bacteria, known as interspecific transfer of electrons, which may have important implications for global carbon cycle and bioenergy. Scientists have found that microorganisms of different species, in this case two Geobacter species, can form direct electrical connection and transmission of electric current from one microbe to another. Working this way two microbes can consume food that none of them can be used independently. Cell aggregates or large ball evolution, Summers developed in the laboratory are very similar to those in nature, involved in degrading organic matter in greenhouse gases, carbon dioxide and methane. Waste methane microbial aggregates becomes increasingly popular way to get natural gas as a renewable source of energy. Others see a lot of methane from the vents on the ocean floor. In both cases, investigators were surprised over the years about how these units function as 40-year interspecific transfer of hydrogen paradigm did not seem responsible supervision. Now the mystery seems solved. As Lovley, head investestigator, explains, we placed the microbes in the environment where they had to work together to survive and thrive with alcohol we gave them as a source of energy. They are the ultimate companions for drinking, working to consume ethanol. In support of the program genomic science U.S. Department of Energy, his laboratory was operating ability of microorganisms to adapt to new conditions and development of microbes for practical application. It has been known since 1960 that microorganisms can indirectly exchange electrons process known as interspecies hydrogen transfer. In it, a microbe produces hydrogen, which then uses another microbe. This experiment doctoral candidate Summers to explore this phenomenon further, leading to the discovery of new direct transfer process. To begin, Summers put two kinds of Geobacter together under conditions expected to favor hydrogen joint interaction. First, cells were co-operate to consume alcohol by hydrogen exchange. Over time, they also started sticking and transforming the culture of a trace of microscopic cells, invisible to the naked eye, to a set of complex multicellular structures millimeters in diameter. Resisting appeals from her lab mates "shake and break the culture of an unexpected accumulation of cells, the summer continues to grow areas. Now they showed a deep red color due to the presence of iron proteins known as cytochromes. When observing with an electron microscope, they clearly developed a complex structure with a number of channels in the visible to food coming. They also created a completely new electrical connections that allowed them to directly share electrons. Direct electron transfer is very efficient and they consume alcohol much faster this way, Summers points. DNA sequencing of large red balls revealed the secret of electrical connection: a mutation in one of the Geobacter species has caused him to do much better known as cytochrome OmcS. Previous studies in the laboratory in a wonderful show that OmcS line along the conductive filaments Geobacter, known as microbial nanowires. This turn of events suggested that the cytochrome is essential for electrical connection between cells says Summers. This was confirmed in subsequent experiments with genetically modified microorganisms. When the researchers removed the genes cytochrome or nanowires, microbes do not form the strattera no prescritpion red balls and not effectively used their alcohol fuel. Lovley, Summers and his colleagues thus prompted a source of new behavior of microbes. Further experiments showed that if the mutation was introduced before the introduction of two Geobacters together, they quickly formed balls and alcohol. Deleting a gene that will be necessary for cells to exchange hydrogen and hastened ball formation, demonstrating that interspecific transfer of hydrogen is an important factor. This is a clear case of life evolving to function more effectively in the new environment says Lovley. We assume that many types of natural aggregates rely on interspecific transfer of an electron said Lovley. We already have good preliminary data for this with some more complex natural systems. In DNA sequencing, we can determine how microbes develop when the challenge to do better. We can learn a lot about the basic mechanisms of the process of interest, he adds. Recommend this story on Facebook, Twitter

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and Google +1: Other Bookmark and collaboration: History Source: above story with materials provided. Note: materials may be edited for content and length. For more information, please contact the source listed above. Journal Links ZM Summers His Fogarty, S. Leanh, AE Franks, NS Malvankar, DR Lovley. Direct exchange of electrons in units evolved Syntrophic Coculture anaerobic bacteria. Science, 2010, 330 (6009): 1413 DOI:

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