KNAW Repository

Diurnal expression of hetR and diazocyte development in the filamentous non-heterocystous cyanobacterium Trichodesmium erythraeum

El-Shehawy, R. and Lugomela, C. and Ernst, A. and Bergman, B. (2003) Diurnal expression of hetR and diazocyte development in the filamentous non-heterocystous cyanobacterium Trichodesmium erythraeum. Microbiology, 149, 1139-1146. ISSN 1350-0872.

[img]PDF - Published Version
Restricted to KNAW only

218Kb

Official URL: http://dx.doi.org/10.1099/mic.0.26170-0

Abstract

The marine non-heterocystous cyanobacterium Trichodesmium fixes atmospheric N2 aerobically in light. In situ immunolocalization/light microscopy of NifH revealed that lighter, non-granulated cell regions observed correspond to the nitrogenase-containing diazocyte clusters in Trichodesmium IMS101. The number of diazocyte clusters per trichome varied from 0 to 4 depending on trichome length. The constant percentage of diazocytes (approx. 15 %) in cultured strains and five natural populations suggests a developmentally regulated differentiation process. Real-time RT-PCR showed that ntcA, encoding the global nitrogen regulator in cyanobacteria, and hetR, the key regulatory gene in heterocyst differentiation, are both constitutively expressed during a 12 h/12 h light/dark cycle. hetR in addition showed a distinct peak in the dark (close to midnight) while nifH expression commenced 6–8 h later. The expression of all three genes was negatively affected by addition of ammonia. Some early heterocyst differentiation genes were also identified in the genome of Trichodesmium. The data suggest that hetR and ntcA may be required for development and function of diazocytes in Trichodesmium

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:11318
Deposited On:24 Nov 2011 01:00
Last Modified:31 Mar 2014 09:59

Repository Staff Only: item control page