HCNSO Student Theses and Dissertations

Defense Date


Document Type


Degree Name

M.S. Marine Biology


Oceanographic Center

First Advisor

Jose Lopez

Second Advisor

Donald S. McCorquodale

Third Advisor

Nwadiuto Esiobu


Interactions among microbial organisms often cannot be observed directly, but they can be inferred genetically using new molecular techniques. The analysis of secondary metabolite gene expression produced by co-cultured marine microbial species allows us to see how these organisms interact with one another when kept in the same environment. Co-cultures of three different strains of marine bacteria, P. aeruginosa PAO1, Roseobacter denitrificans OCH114, and Salinispora arenicola CNS-205 were grown in a laboratory setting, and using the Real-Time qPCR method gene expression levels of two different secondary metabolite producing genes from each organism was accessed across three time points. P. aeruginosa PAO1’s secondary metabolite genes RdhA and PhzH stayed repressed through all co-cultures and time points in this study, and Roseobacter denitrificans OCH-114’s secondary metabolite genes metallo-beta-lactamase and DMSP lyase were up-regulated after the 30 minute time point in the P. aeruginosa-R. denitrificans co-culture and at the 0 minute time point in the R. denitrificans-S. arenicola co-culture.

DOC091817.pdf (937 kB)

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