Ammonium (methylammonium) transport by heterocysts and vegetative cells of Anabaena variabilis.
نویسندگان
چکیده
Transport of the ammonium analogue [(14)C]methylammonium was similar in non-growing, fully differentiated heterocysts as compared to vegetative, multiplying cells of the filamentous cyanobacterium Anabaena variabilis. NH(4)(+) inhibited uptake into the cells and released accumulated methylammonium from the cells. These observations suggest that the main function of ammonium transport in heterocysts may not be NH(4)(+) acquisition but cyclic retention of ammonia produced by nitrogenase.
منابع مشابه
Effect on heterocyst differentiation of nitrogen fixation in vegetative cells of the cyanobacterium Anabaena variabilis ATCC 29413.
Heterocysts are terminally differentiated cells of some filamentous cyanobacteria that fix nitrogen for the entire filament under oxic growth conditions. Anabaena variabilis ATCC 29413 is unusual in that it has two Mo-dependent nitrogenases; one, called Nif1, functions in heterocysts, while the second, Nif2, functions under anoxic conditions in vegetative cells. Both nitrogenases depended on ex...
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متن کاملA second nitrogenase in vegetative cells of a heterocyst-forming cyanobacterium.
In many filamentous cyanobacteria nitrogen fixation occurs in differentiated cells called heterocysts. Filamentous strains that do not form heterocysts may fix nitrogen in vegetative cells, primarily under anaerobic conditions. We describe here two functional Mo-dependent nitrogenases in a single organism, the cyanobacterium Anabaena variabilis. Using a lacZ reporter with a fluorescent beta-gal...
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ورودعنوان ژورنال:
- FEMS microbiology letters
دوره 181 2 شماره
صفحات -
تاریخ انتشار 1999