Veronica Robertson

 Gorgonian octocorals are predominant members of Caribbean reefs and in certain regions, Pseudopterogorgia elisabethae is one of the most common gorgonians.  This coral has been the subject of numerous natural product investigations, yet very little is known regarding the community and diversity of its symbiotic bacterial assemblages.  Furthermore, P. elisabethae is the sole known source of pseudopterosins, biologically active diterpene glycosides marketed in Estée Lauder cosmetics with a market value of $3 - 4 million. Recent research within the Kerr lab has pointed to a microbial origin of the pseudopterosins, once previously assumed to be attributed to the host (Look et al, 1986). Despite the economical and environmental importance of this gorgonian, in addition to the link suggesting microbial origin of natural products, the bacterial community of P. elisabethae has not been addressed.

Research Aims:

 1) To assess the culture-independent bacterial community and diversity of P elisabethae.   The community and diversity of P. elisabethae corals (n=14) from 3 sites within the Bahamas was characterized using next generation pyrosequencing methods targeting the bacteria specific 16S rRNA gene. 16S rRNA gene sequences were analyzed at the “class” level (operational taxonomic unit (OTU) cutoff of 10% sequence dissimilarity, OTU_0.10) and at the “species” level (OTU_0.03) to determine lower-level taxonomic influence on shaping coral-associated bacterial communities. Dominant OTU_0.03s (≥1% sequence abundance) were analyzed by Principal Component Analysis to determine the extent of individual phylotypes on driving the separation of coral-associated bacterial libraries.

2) To assess the cultivable bacterial community of P. elisabethae. Previous research has demonstrated <1% of bacteria may be cultured using traditional plating techniques, thus, we incorporated a wide variety of media conditions (varying solidifying agents, nutrient compositions, and dilutions) into our study design. Approximately 800 cultures were obtained, and isolates were dereplicated using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS).

3) To assess the antimicrobial potential of bacterial cultures from P. elisabethae. De-replicated isolates described above were fermented, extracted, and tested for bioactivity via a wide range of in-house antimicrobial assays. Bacteria demonstrating activity in antimicrobial assays were re-fermented and extracted to confirm bioactivity. Currently, approximately 5 members of natural product producing genera are being screened using an activity-guided isolation, where active compounds will be separated using ultra high performance liquid chromatography and the identity will be deduced using NMR spectroscopy.

 
Education:

·         PhD., Biomedical Sciences (2007 – present)  

o    University of Prince Edward Island, PE

·          B.Sc., Biochemistry & Molecular Biology (2003 – 2007)

o    Trent University, Peterborough, ON, Canada