Nanotube-mediated cross-feeding couples the metabolism of interacting bacterial cells |
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Authors: | Shraddha Shitut Tobias Ahsendorf Samay Pande Matthew Egbert Christian Kost |
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Affiliation: | 1. Experimental Ecology and Evolution Research Group, Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena 07745, Germany;2. Deutsches Krebsforschungszentrum, Baden-Württemberg 69120, Heidelberg, Germany Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA;3. Department of Computer Science, University of Auckland, Auckland 1010, New Zealand |
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Abstract: | Bacteria frequently engage in cross-feeding interactions that involve an exchange of metabolites with other micro- or macroorganisms. The often obligate nature of these associations, however, hampers manipulative experiments, thus limiting our mechanistic understanding of the ecophysiological consequences that result for the organisms involved. Here we address this issue by taking advantage of a well-characterized experimental model system, in which auxotrophic genotypes of E. coli derive essential amino acids from prototrophic donor cells using intercellular nanotubes. Surprisingly, donor–recipient cocultures revealed that the mere presence of auxotrophic genotypes was sufficient to increase amino acid production levels of several prototrophic donor genotypes. Our work is consistent with a scenario, in which interconnected auxotrophs withdraw amino acids from the cytoplasm of donor cells, which delays feedback inhibition of the corresponding amino acid biosynthetic pathway and, in this way, increases amino acid production levels. Our findings indicate that in newly established mutualistic associations, an intercellular regulation of exchanged metabolites can simply emerge from the architecture of the underlying biosynthetic pathways, rather than requiring the evolution of new regulatory mechanisms. |
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