Production of Copper-Complexing Ligands in Response to Elevated Concentrations of Copper in Marine <i>Synechococcus</i> spp.

<p><em>Synechococcus</em> spp. (marine cyanobacteria) are extremely sensitive to copper toxicity and can produce high-affinity ligands of unknown structure which form complexes with free cupric ion. These ligands may contribute to the biological control of the levels of free cupric ions in surface seawater. <em>Synechococcus</em> spp. are known to produce metallothioneins (MT) in response to cadmium and zinc stress. In the present study the hypothesis that marine <em>Synechococcus</em> produce MT in response to copper was tested. Three marine <em>Synechococcus</em> spp. i.e., PCC 7001, PCC 73109, and PCC 7003, were exposed to different concentrations of CUSO 4 for various time periods. Size exclusion chromatography, atomic absorption spectrophotometry, and reverse phase HPLC were used to isolate an intracellular copper binding component (CBC) of low molecular weight (Synechococcus PCC 73109 produced an intracellular CBC after exposure to [special characters omitted]8 μM CuSO₄ for 2 hr. The intracellular CBC was shown not to be MT, phytochelatin or a siderophore. It is not a peptide; it contains lysine and an unidentified UV 254-absorbing component. This compound is a novel copper-binding ligand previously not reported in <em>Synechococcus </em>spp. and may function as a component of a copper export system.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Year dc:date.available

1999

Author dc:creator

• Brown, Arunsri Chatkaeomorakot

Contributors dc:contributor

• Andrew S. Gordon
• Christopher Osgood
• Wayne Hynes
• Patricia A. Pleban

• Copper-complexing
• Ligands
• Marine
• Metallothioneins
• Synechococcus
• Biochemistry
• Molecular Biology
• Oceanography

Identifier

9780599285224

OAI identifier oai:identifier

oai:digitalcommons.odu.edu:biomedicalsciences_etds-1009