Molecular Biology and Genetics

Microbial Biotechnology

Electronic Journal of Biotechnology ISSN: 0717-3458 Vol. 10 No. 4, Issue of October 15, 2007
© 2007 by Pontificia Universidad Católica de Valparaíso -- Chile Received September 21, 2006 / Accepted April 17, 2007
DOI: 10.2225/vol10-issue4-fulltext-2

Experimental and bioinformatic approaches for analyzing and visualizing cyanobacterial nitrogen and hydrogen metabolism

Röbbe Wünschiers*#
Institute for Genetics
University of Cologne
Tel: 49 39482 760112
Fax: 49 39482 760199

Rikard Axelsson
Swedenborgsgatan 41 C 753 34
Uppsala, Sweden
Tel: 46 18 4891216
Fax: 46 18 4891022

Martin Vellguth
Institute for Genetics
University of Cologne
Zülpicher Str. 47
50674 Cologne, Germany
Tel: 49 221 4705661
Fax: 49 221 4705975

Peter Lindblad
Department Photochemistry and Molecular Science
The Ångström Laboratories
Uppsala University
Box 523, 751 20 Uppsala, Sweden
Tel: 46 18 471 2826
Fax: 46 18 471 6844

*Corresponding author

Financial support: This work is part of the BMBF-funded Cologne University Bioinformatics Center (CUBIC) and was financially supported by grants to PL from the Swedish Research Council, the Swedish Energy Agency, and the EU/NEST Project SOLAR-H (contract 516510).

Keywords: bioinformatics, cyanobacteria, DNA-microarrays, gene expression, metabolic pathways, nitrogen availability, nitrogen fixation.

Present address: #SunGene GmbH & Co KGaA, Correnstrasse 3, 06466 Gatersleben, Germany.


ATP: adenosine 5'-triphosphate
BSA: bovine serum albumin
CAB: chlorophyll a/b-binding
ELIP: early light-induced proteins
GC: guanine/cytosine nucleotides
HLIP: high light-induced stress proteins
KEGG: Kyoto encyclopedia of genes and genomes
ORF: open reading frame

Full Text

Many cyanobacteria are capable of utilizing light energy for nitrogen fixation. As a by-product of this nitrogenase mediated catalysis, hydrogen gas is produced. Several approaches to increase hydrogen production from cyanobacteria exist. Usually, these approaches are non-targeted. Here we exemplify how DNA-microarray based gene-expression analysis and bioinformatic visualization techniques can be used to analyze nitrogen and hydrogen metabolism from the filamentous, heterocyst forming cyanobacterium Nostoc PCC 7120. We analyzed the expression of 1249 genes from major metabolic categories under nitrogen fixing and non-nitrogen fixing growth. Of the selected genes, 494 show a more than 2-fold expression difference in the two conditions analyzed. Under nitrogen-fixing conditions 465 genes, mainly involved in energy metabolism, photosynthesis, respiration and nitrogen-fixation, were found to be stronger expressed, whereas only 29 genes showed a stronger expression under non-nitrogen fixing conditions. To help understanding probe hybridization, all expression data were correlated with potential target secondary structures and probe GC-content. For the first time the expression of high light-induced stress proteins (HLIP-family) is shown to be linked to the nitrogen availability.

Supported by UNESCO / MIRCEN network