Lack of control of nitrite assimilation by ammonium in an oceanic picocyanobacterium, Synechococcus sp. strain WH 8103.

ABSTRACT: In cyanobacteria, the transcriptional activator NtcA is involved in global nitrogen control and, in the absence of ammonium, regulates the expression of genes involved in the assimilation of alternative nitrogen sources. The oceanic picocyanobacterium Synechococcus sp. strain WH 8103 harbors a copy of ntcA, but in the present study, we show that unlike other marine cyanobacteria that have been investigated, this strain is capable of coassimilating nitrite when grown in the presence of ammonium. Transcript levels for the genes encoding the nitrate/nitrite-bispecific permease NrtP and nitrate reductase (NarB) were substantially down-regulated by ammonium, whereas the abundances of nitrite reductase (NirA) transcripts were similar in nitrite- and ammonium-grown cells. The growth of Synechococ

SUBMITTER: Wyman M 

PROVIDER: S-EPMC1892888 | biostudies-literature | 2007 May

REPOSITORIES: biostudies-literature