The Robertson Lab Members

Interests

I received my Master’s Degree in Botany form Tribhuvan University, Nepal. My major for my master’s work was plant biotechnology and biochemistry and my master’s thesis focused on symbiotic nitrogen fixation. As I am interested in many aspects of nitrogen metabolism in photosynthetic eukaryotes, I joined the Robertson lab in fall 2008

The assimilation of nitrogen has marked effects on the primary productivity, biomass, and crop yield of an ecosystem. Organisms use inorganic compounds (nitrate, nitrite or ammonia) as sources of nitrogen for amino acid biosynthesis. Before incorporating nitrogen into amino acids, nitrate and nitrite are reduced to ammonia through series of enzymatic reactions. First, the 2-electron reduction of nitrate to nitrite is catalyzed by nitrate reductase and the further 6-electron reduction of nitrite to ammonia is catalyzed by nitrite reductase. My research primarily focuses on nitrite reductase. Nitrite reductase in green algae and higher plants is localized inside chloroplast and utilizes ferredoxin as electron donor (Fd-NiR), while in fungi and in bacteria nitrite reductase is localized in cytoplasm and utilize NAD(P)H as electrondonor (NAD(P)H-NiR). Previous work in this lab examined the diurnal expression patterns of both Fd-NiR and NAD(P)H-NiR in the marine diatom Thalassiosira pseudonana.  I am interested in exploring the cellular mechanisms that regulate the expression of these two genes.  Knowledge of the  expression and regulatory mechanisms of these two nitrite reductases will contribute to our understanding of both the cellular function of each enzyme and their contribution to the ecological competency of the organism.