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. 1984 Mar;81(5):1566–1569. doi: 10.1073/pnas.81.5.1566

Rhizobium free-living nitrogen fixation occurs in specialized nongrowing cells

Robert A Ludwig 1
PMCID: PMC344878  PMID: 16593433

Abstract

A model for free-living N2 fixation by Rhizobium sp. RC3200 is presented that asserts that this process occurs in nongrowing cells. Cultures containing mixed populations of cell types, N2-fixing and vegetative, grow cooperatively. In nitrogen-limited liquid suspension cultures, cooperative growth occurs by means of ammonium that is produced and exported by nongrowing, N2-fixing cells and transported to vegetative cells. This model implies prokaryotic differentiation: the creation of metabolically specialized cells, terminally nonviable, that functionally cooperate in a higher cell order. Here, the switch to a Rhizobium N2-fixing cell state is regulated by both O2 and utilizable nitrogen.

Keywords: prokaryotic differentiation, syntrophism

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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