Aquatic Sciences Meeting, Albuquerque 2001

SS14 Microbial Diversity (Disciplinary Connections)

Date: Monday, February 12, 2001, Time: 11:00:00 AM

Location: Brazos

Lindell, D, , Hebrew University of Jerusalem, H. Steinitz Marine Biology Laboratory, Eilat, Israel, debbie@vms.huji.ac.il

Post, A, F, Hebrew University of Jerusalem, H. Steinitz Marine Biology Laboratory, Eilat, Israel, anton@vms.huji.ac.il

ASSESSING THE NITROGEN STATUS OF MARINE PICOCYANOBACTERIA FROM NTCA GENE EXPRESSION

Phytoplankton biomass is thought to be limited by nitrogen availability in many oligotrophic bodies of water. Molecular methods have the potential for assessing the nitrogen status of phytoplankton along taxonomic lines. NtcA is a cyanobacterial specific transcriptional activator that plays a central role in nitrogen acquisition and metabolism. We have developed a protocol based on the rapid and specific response of ntcA gene expression to nitrogen availability to distinguish between three nitrogen states in marine picocyanobacteria. Basal ntcA expression is indicative of the utilization of ammonium and therefore infers regenerated production. Maximal ntcA expression is characteristic of nitrogen deprivation. Intermediate transcript levels attest to the utilization of a nitrogen source, the identity of which is not unequivocally determined using this protocol. Analysis of ntcA gene expression using RT-PCR with primers that specifically amplify ntcA from either Synechococcus or Prochlorococcus or from distinct lineages within each genus enables the determination of the nitrogen status of field populations of cyanobacteria at various taxonomic levels.

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Aquatic Sciences Meeting, Albuquerque 2001

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