Ammonium (methylammonium) transport by heterocysts and vegetative cells of Anabaena variabilis

Ammonium (methylammonium) transport by heterocysts and vegetative cells of Anabaena variabilis.

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 heteroc...

Ammonium (methylammonium) transport by Azospirillum spp

In recent years soil bacteria of the genus Azospirillum found increasing biological and ecological interest because of their ability to microaerobically fix N 2 and to live in close association with plant roots, stimulating growth of nitrogenlimited plants [1-5]. The physiology of N 2 fixation, especially its repression by N H + , has been studied extensively [6-9]. The question, however, how N...

Transport of ammonium and methylammonium ions by Azotobacter vinelandii.

Ammonium and methylammonium are rapidly taken up by cultures of Azotobacter vinelandii respiring in the presence of succinate. The rate of methylamine uptake increased with external pH from 5.5 to 7.5 but increasing the pH further to 8.5 had little effect on activity, indicating that methylammonium cation rather than uncharged methylamine is the permeant species. The kinetics of methylammonium ...

Potassium ion transport and electrogenesis in Anabaena variabilis.

Posttranscriptional regulation of glutamine synthetase in the filamentous Cyanobacterium Anabaena sp. PCC 7120: differential expression between vegetative cells and heterocysts.

Genes homologous to those implicated in glutamine synthetase (GS) regulation by protein-protein interaction in the cyanobacterium Synechocystis sp. strain PCC 6803 are conserved in several cyanobacterial sequenced genomes. We investigated this GS regulatory mechanism in Anabaena sp. strain PCC 7120. In this strain the system operates with only one GS inactivation factor (inactivation factor 7A ...