Ferritin Gene Expression among Pennate and Centric Diatoms
Public Deposited- Last Modified
- February 26, 2019
- Creator
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Stemple, Brooke
- Affiliation: College of Arts and Sciences, Curriculum in Environment and Ecology, Environmental Studies
- Abstract
- The ability to store iron through the use of iron storage proteins, ferritins, has evolved as an advantageous strategy for numerous diatom species. Iron is a micronutrient in the ocean that typically exists at low concentrations throughout much of the marine system. Therefore, iron deficiency often plays a central role in controlling primary productivity, and thus, diatom populations within the ocean (Martin, 1990). This project investigates the expression of an iron storage gene, ferritin, in three pennate diatoms and four centric diatoms. The strains were cultured at Bigelow Laboratory for Ocean Sciences and the University of North Carolina at Chapel Hill (UNC) and grown as triplicate cultures under various iron conditions. This experiment allowed for the comparison of ferritin gene expression along with iron storage capabilities, in contrasting iron environments among phylogenetically distinct diatoms. This was achieved by utilizing the ΔCt method. Our results suggest that pennates may upregulate ferritin levels in high iron environments. Marchetti et al (2009) similarly demonstrated that pennates such as Pseudo-nitzschia granii store iron during temporary pulses, which allows them to continue to proliferate once iron limited conditions return. Two of the examined centrics, however, demonstrated greatest ferritin gene expression under low iron conditions. This result is counterintuitive, as ferritin is a storage gene and high expression during low iron levels appears inefficient. However, this finding supports the theory that centrics may be using their ferritin as an iron buffer and thus eludes to physiological differences in the way these two diatom lineages are storing iron and utilizing their ferritin genes. There is also evidence of a biogeographical distinction among ferritin use in certain species. Diatoms in open ocean regions, where iron is often limited, may be utilizing their ferritin differently than those persisting in high-iron coastal areas.
- Date of publication
- autumn 2015
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- DOI
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- Rights statement
- In Copyright
- Note
- Funding: National Science Foundation
- Advisor
- Marchetti, Adrian
- Degree
- Bachelor of Science
- Honors level
- Honors
- Degree granting institution
- University of North Carolina at Chapel Hill
- Extent
- 20
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