Article Abstract:
Nodulation (nod) gene inducers secreted by alfalfa roots are chemotactic to Rhizobium meliloti cells. This is similar to the response obtained using luteolin, a flavone, found in alfalfa seed extracts. This attraction could serve as a mechanism to bring R. meliloti cells to areas with high inducer concentrations, thereby amplifying nod gene induction. It could also serve to enhance growth by attracting cells to areas of high nutrient content. Even though both have the same biochemical specificity, the mechanism behind this chemotaxis appears distinct from that of nod gene induction.
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Article Abstract:
The Tn5 mutants of Sinorhizobium meliloti RMB7201 that swarmed 1.5 to 2.5 times faster than the parental strain in semisolid agar, moist sand and viscous liquid have been isolated and identified. The mutants outgrew the wild type strain 30- to 40-fold within 2 days. They also survived and grew better than the wild strain under all testing conditions except in a soil matrix subjected to air drying. It has been discovered that the swarming behavior is influenced by spontaneous and high-frequency switching between normal and faster-swarming activities.
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Article Abstract:
Three strains of Rhizobium meliloti, a nitrifying bacteria that nodulates alfalfa, were used in the investigation of the motility response of the bacteria to starvation. In particular, the effect of a medium that lacks carbon, nitrogen and phosphate sources on motility, chemotactic response and flagellation, the interaction among these parameters and variation in the response to starvation are examined.
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