Faculty Biography

Deborah Robertson

Deborah L. Robertson, Ph.D.

Professor of Biology
Adjunct Professor, Carlson School of Chemistry and Biochemistry
Department of Biology
Biochemistry and Molecular Biology Program
Clark University
15 Maywood St.
Worcester, MA 01610-1477

Office: #231; Lab: #224
Phone: (508) 793-7515
Email: DebRobertson[at]clarku.edu

Curriculum Vitae
Research Lab Website


Ph.D. The University of Chicago
M.S. California State University, Long Beach
B.A. Kalamazoo College

Current Research and Teaching

My research program investigates the physiological ecology and the evolution of nitrogen metabolism in marine diatoms and other ecologically important groups of marine algae. In many marine environments, nitrogen availability is an important factor regulating primary productivity. By characterizing the enzymes and regulatory pathways involved in nitrogen metabolism, this work will contribute to our understanding of the coupling between nitrogen metabolism and productivity.

The assimilation of inorganic nitrogen (N) into organic compounds is a key process regulating the growth and productivity of photosynthetic eukaryotes. Diatoms are unicellular photoautotrophs that contribute significantly to global biochemical cycles. They exhibit rapid growth in response to increases in N availability, which in marine ecosystems, varies over several spatial (meters to kms) and temporal scales (hours to months). Thus, the ecological success of diatoms can, in part, be attributed to their ability to rapidly sense and respond to fluctuations in N source and supply.

In all living cells, the regulation of gene expression is a multifaceted and dynamic process. Cells integrate intrinsic and environmental signals into multiple regulatory pathways allowing for coordinated gene expression and cellular function. While there has been much focus on patterns of coordinated gene transcription, there are now examples from bacteria, kinetoplastids, plants, fungi, and animals of coordinated post-transcriptional regulation of mRNAs encoding functionally related proteins.  This project explores the general hypothesis that post-transcriptional regulation of genes involved in N transport and assimilation in marine diatoms allows for rapid metabolic response to perturbations in nutrient source or supply and is mediated by changes in mRNA stability.

The evolutionary history of several algal lineages is complex and riddled with endosymbiotic events, gene duplications, gene transfers, and gene losses.  These genomic alterations would have required modification of metabolic and regulatory pathways and suggest that the regulation of metabolic pathways will vary among of the algal lineages. We are exploring the molecular evolution of nitrogen assimilating enzymes in select lineages of algae.  This research will contribute to our understanding of the cellular processes that regulate oceanic productivity and of the impact of anthropogenic nutrients on marine ecosystem. The work should also contribute to our understanding of the evolution of nitrogen metabolism in photosynthetic eukaryote

Selected Publications

Ghoshroy, S. and D.L. Robertson. 2015. The role of horizontal gene transfer in the evolution of nitrogen assimilating enzymes in the Prasinophytes. Journal of Molecular Evolution. 80(1):65-80. doi: 10.1007/s00239-014-9659-3. Epub 2014 Dec 11.

Boissonneault, K.R., B.M. Henningsen, S.S. Bates, D.L. Robertson, S. Milton, J. Pelletier, D.A. Hogan, and D.E. Housman. 2014. Gene expression studies for the analysis of domoic acid production in the marine diatom Pseudo-nitzschia multiseries. BMC Molecular Biology. 14:25 doi:10.1186/1471-2199-14-25

Ghoshroy S. and D.L. Robertson. 2012. Molecular evolution of glutamine synthetase II and III in the chromalveolates J. Phycol. 48:768-783

Ghoshroy, S. M. Binder, A. Tartar, and D.L. Robertson. 2010. Molecular evolution of glutamine synthetase II: Phylogenetic evidence of a non-endosymbiotic gene transfer event early in plant evolution BMC Evolutionary Biology, 10:198. doi:10.1186/1471-2148-10-198

Brown, K.L., K.I. Twing, and D.L. Robertson. 2009. Unraveling the regulation of nitrogen assimilation in the marine diatom Thalassiosira pseudonana (BACILLARIOPHYCEAE): Diurnal variation in transcript levels for five genes involved in nitrogen assimilation. J. Phycol.45:413-426.

Banerjee, G., D.L. Robertson, T. Leonard. 2008. Hydrophobins Sc3 and Sc4 gene expression in mounds, fruiting bodies and vegetative hyphae of Schizophyllum commune. Fungal Genet. Biol., 45: 171-178 (doi:10:1016/j.fgb.2007.10.018)

Robertson, D.L. and A. Tartar. 2006. Evolution of glutamine synthetase in heterokonts: evidence for endosymbiotic gene transfer and the early evolution of photosynthesis. Mol. Biol. Evol. 23(5):1048-1055. [Abstract][PDF]

Takabayashi, M., F.P. Wilkerson and D.L. Robertson. 2005. Response of glutamine synthetase gene transcription and enzyme activity to external nitrogen sources in the diatom, Skeletonema costatum (Bacillariophyceae). J. Phycol. 41:84-94

Robertson, D.L., G.J. Smith, and R.S. Alberte. 2001. Glutamine synthetase in marine algae: New surprises from an old enzyme. J. Phycol. 37(5): 793-795

Okamoto, O.K., D.L. Robertson, T.Fagan, J.W. Hastings and P. Colepicolo. 2001. Different regulatory mechanisms modulate the expression of a dinoflagellate iron-superoxide dismutase. J. Biol. Chem.. 276: 19989-19993.

Li, L., L. Liu, R. Hong, D.L. Robertson, and J.W. Hastings. 2001. N-terminal histidines are responsible for the decrease in luciferase activity at pH 8. Biochemistry. 40(6):1844-1849.

Robertson, D.L., G.J. Smith, and R.S. Alberte. 1999. Characterization of a cDNA encoding glutamine synthetase from the marine diatom Skeletonema costatum. J. Phycol. 35:786-797.

Robertson, D.L., and R.S. Alberte. 1996. Purification and biochemical characterization of glutamine synthetase from Skeletonema costatum. Plant Physiol. 111:1169-1175.

Coyer, J.A., D.L. Robertson, R.S. Alberte. 1995. Genetic variability and parentage in Macrocystis pyrifera (Phaeophyceae) using multi-locus DNA fingerprinting. J. Phycol. 31:819-823.

Coyer, J.A., D.L. Robertson, and R.S. Alberte. 1994. Genetic variability within a population and between diploid/haploid tissue of Macrocystis pyrifera (Phaeophyceae). J. Phycol. 30:545-552.

Urbach, E., D.L. Robertson, and S.W. Chisholm. 1992. Multiple origins of prochlorophytes revealed by 16s rRNA phylogeny. Nature. 335:267-270.

Swift, H. and D.L. Robertson. 1991. Structural aspects of a Prochloron-tunicate symbiosis. Symbiosis. 10:95-113.

Bray, R.N., A.C. Miller, S.C. Johnson, P.R. Krausse, D.L. Robertson, A.M. Westcott. 1988. Ammonium excretion by macroinvertebrates and fishes on a subtidal rocky reef in southern California. Mar. Biol. 100:21-30.

Zimmerman, R.C. and D.L. Robertson. 1986. Effects of El Nino on local hydrography and growth of the giant kelp, Macrocystis pyrifera, at Santa Catalina Island, California. Limnol. Oceanogr. 30(6):1298-1302.


Federal Grants as Principal Investigator:

Robertson, D.L. 2011-2015. Regulation of nitrogen assimilation in marine diatoms: Investigation of the importance of post-transcriptional processes. National Science Foundation (Funded: $385,381, 36 mos, 1 year no cost extension)

Robertson, D.L. 2003-2009. CAREER: Nitrogen Assimilation in Marine Algae: Evolution, Physiology, and Educational Opportunities. National Science Foundation. (Funded: $541,433, 60 mos with 1 year no cost extension).

Robertson, D.L. May 2005 - 2007. REU Supplement for CAREER: Nitrogen Assimilation in Marine Algae: Evolution, Physiology, and Educational Opportunities. National Science Foundation. (Funded: 2007: $6,000 12 mos; 2006: $6,000 12 mos; 2005: $11,340 12 mos)

Robertson, D.L. July 1997. Translational regulation of a circadian expressed protein. Individual National Research Service Award, National Institutes of Health. (Funded: $87,168, 36 mos.)

Institutional Awards as Principal Investigator:

Robertson, D.L. 2013-2014. Population Genetic Structure of Two Seagrass Species in a Mixed Species Ecosystem (Padilla Bay, WA, USA) Faculty Development Award, Clark University (Funded: $1369)

Collaborative Grants and Awards:

Smith, G.J. (Lead) and D.L. Robertson. 2015-2016. Application of electroporation for transfection and transformation of the cosmopolitan diatom genus Pseudo-nitzschia to enable molecular dissection of domoic acid biosynthesis. Gordon and Betty Moore Foundation: Experimental Model Systems.  ($171,842 12 mos.)

Del Prete, T., L.J. Smith, D.L. Robertson, A. A. Kudrolli, N. C. Sternberg. 2013-2018. Clark Science Math Teaching and Education Partnership (C-STEP) funded by the Robert Noyce Teacher Scholarship Program ($1,130,705, 60 mos.)

Foster, S.A., Livdahl, T., Robertson, D.L., and Hibbett, D.S. (co-directors). 2006. Complementary Curricular Networks: Tools to Enhance Undergraduate Biology Education. (Funded: $300,000)

Livdahl, T. (PI) and Robertson, D.L. (Co-PI). 2005-2009. Ecology of large and small scale mosquito invasions. NIH, Academic Research Enhancement Award (Funded: $216, 900, 36 mos; with a 1 year no cost extension)