Ammonia differentially suppresses the cAMP chemotaxis of anterior-like cells and prestalk cells indictyostelium discoideum
Autor: | Erika J. Medynski, Michael J. Rothrock, Ira N. Feit |
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Rok vydání: | 2001 |
Předmět: |
Slug
Cell Buffers General Biochemistry Genetics and Molecular Biology Dictyostelium discoideum law.invention Ammonia chemistry.chemical_compound law Cyclic AMP Morphogenesis medicine Animals Dictyostelium biology Chemotaxis fungi food and beverages General Medicine Fruiting body formation Hydrogen-Ion Concentration biology.organism_classification Cell biology medicine.anatomical_structure Biochemistry chemistry Suppressor General Agricultural and Biological Sciences |
Zdroj: | Journal of Biosciences. 26:157-166 |
ISSN: | 0973-7138 0250-5991 |
Popis: | A drop assay for chemotaxis to cAMP confirms that both anterior-like cells (ALC) and prestalk cells (pst cells) respond to cAMP gradients. We present evidence that the chemotactic response of both ALC and pst cells is suppressed by ammonia, but a higher concentration of ammonia is required to suppress the response in pst cells. ALC show a chemotactic response to cAMP when moving on a substratum of prespore cells in isolated slug posteriors incubated under oxygen. ALC chemotaxis on a prespore cell substratum is suppressed by the same concentration of ammonia that suppresses ALC chemotaxis on the agar substratum in drop assays. Chemotaxis suppression is mediated by the unprotonated (NH3) species of ammonia. The observed suppression, by ammonia, of ALC chemotaxis to cAMP supports our earlier hypothesis that ammonia is the tip-produced suppressor of such chemotaxis. We discuss implications of ammonia sensitivity of pst cells and ALC with regard to the movement and localization of ALC and pst cells in the slug and to the roles played by ALC in fruiting body formation. In addition, we suggest that a progressive decrease in sensitivity to ammonia is an important part of the maturation of ALC into pst cells. |
Databáze: | OpenAIRE |
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