Research
Below are some completed and ongoing research projects
Research at the University of North Carolina, Marchetti and Septer Labs:
Antarctic diatom proteorhodopsins: characterization and a potential role in the iron-limitation response
Following the discovery of a proteorhodopsin-like gene in diatoms by the Marchetti Lab, it was found that diatom-proteorhodopsin is especially common in Southern Ocean diatom isolates compared to temperate species, suggesting proteorhodopsin may be a polar adaptation that plays a role in iron-limitation response.
Proteorhodopsins use a retinal chromophore to absorb light, and pump protons across membranes. These proton gradients could potentially be used to power other transporters, or create ATP. My work seeks to couple physiological measurements and 'omics to determine the conditions under which proteorhodopsin is preferentially expressed. To further understand how proteorhodopsin functions, I am using immunofluorescence microscopy to understand where proteorhodopsin is located within the cell.
Stay tuned for updates, research currently underway!
Proteorhodopsins use a retinal chromophore to absorb light, and pump protons across membranes. These proton gradients could potentially be used to power other transporters, or create ATP. My work seeks to couple physiological measurements and 'omics to determine the conditions under which proteorhodopsin is preferentially expressed. To further understand how proteorhodopsin functions, I am using immunofluorescence microscopy to understand where proteorhodopsin is located within the cell.
Stay tuned for updates, research currently underway!
Research from the Australian National University:
Examining the regulation of photosynthetic proteins between Southern Ocean and temperate diatoms
Iron plays an essential role in photosynthesis, where light and carbon dioxide are needed to create organic carbon and fuel cellular growth. Diatoms have adapted to the low iron concentrations in the Southern Ocean in a variety of ways. These strategies differ between species and include, but are not limited, to the reorganisation of proteins in photosynthesis, or substituting iron containing enzymes for metal-free enzymes or enzymes that utilize other metals. Usually temperate, coastal and oceanic diatoms increase intracellular iron concentrations, by increasing the number of proteins required for photosynthesis, to optimize photosynthesis under low light levels. However, this does not happen in Southern Ocean diatoms, which have adapted to the low light and low iron conditions of the Southern Ocean.
Andrew et al., (in revision) Evolution of a more CO2-specific and carboxylation efficient diatom Rubisco in a polar environment
Andrew et al., (2021) Divergent physiological and molecular responses of light and iron limited Southern Ocean phytoplankton
Andrew et al., (in revision) Evolution of a more CO2-specific and carboxylation efficient diatom Rubisco in a polar environment
Andrew et al., (2021) Divergent physiological and molecular responses of light and iron limited Southern Ocean phytoplankton
Individual and combined effects of carbon dioxide, temperature, light and iron in Southern Ocean phytoplankton
Southern Ocean productivity is limited by low iron, light, and temperature, which restrict the efficiency of the carbon pump. Model projections indicate that light, temperature and Fe in the Southern Ocean are likely to change simultaneously in the future due to increasing carbon dioxide emissions, however we have very little understanding about the evolutionary ramifications of Antarctic phytoplankton to such environmental changes.
Andrew et al. (2019) Iron availability influences the tolerance of Southern Ocean phytoplankton to warming and elevated irradiance
Andrew et al. (2022) Ocean acidification reduces the growth of two Southern Ocean phytoplankton
Andrew et al. (2019) Iron availability influences the tolerance of Southern Ocean phytoplankton to warming and elevated irradiance
Andrew et al. (2022) Ocean acidification reduces the growth of two Southern Ocean phytoplankton