Oana Marcu

Oana Marcu
Research Scientist
Degree/Major: 
Ph.D.
Discipline: 
Biology

Oana Marcu’s research interests include molecular adaptations of cells to extreme habitats on Earth, as analogs for Mars environments that could harbor life. Survival of life in deserts requires adaptation to desiccation, extreme temperatures and radiation, which limit the presence of life. For extremophiles, adaptation implies maintaining the structural and functional integrity of biomolecules (DNA, protein, lipids), which are otherwise damaged through oxidation.

Oana's research projects look at adaptive responses in microbial communities from two environmental niches in dry deserts, Atacama halites and Mojave soils; the response to stress in uni- and multicellular organisms and the specification of cell fate; elemental mapping to determine mechanisms of adaptation to transient environmental stress; cellular and physiological responses to changes in radiation and microgravity.   A main interest is in determining the conservation of functional genetic pathways that allow adaptation and survival, during evolution. Aspects of these projects include molecular biology laboratory work (cloning, assays for quantifying gene expression and molecular damage etc); biochemistry and microbiology assays; bioelemental imaging and quantification using X-ray fluorescence and spectroscopy at the Stanford Linear Accelerator Center on beamlines 2-3, 6-2 and 7-3.  These projects are currently suported by NASA SMD (Exobiology) and HEOMD (Fundamental Space Biology), and two proposals awarded at SSRL.

Oana also initiated the STEP (Science, Technology and Exploration Program), an Astrobiology Science Camp for students and teachers she ran in collaboration with her colleagues at NASA Ames and SETI in 2009-2011 (http://advancedstudieslabs.org/step) with grant support from NASA SMD Education Office and local support from NASA Ames Research Center, Lockheed Martin, the Ames Contractor Council and from volunteers from the Silicon Valley and international community.

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Intracellular Redox Control for Adaptation and Survival in Planetary Environments

This project is centered around the hypothesis that exposure to environmental extremes results in intracellular oxidative stress, which is modulated by the elemental content of cells. We are using X-ray fluorescence imaging and X-ray transmission microscopy at SSRL (Stanford Synchrotron Radiation Lightsource) to map the elemental composition of halophilic cyanobacteria from the Atacama desert and of green algae, and determine changes that may represent responses to transient fluctuations in the environment. Linking these with the genomic and molecular changes in cells helps uncover a possible mechanism of adaptation and evolution.

Oxidative Stress Responses in Altered Gravity

This project looks at the role of oxidative stress responses in the adaptation to changes in the gravity vector, using Drosophila melanogaster as a model organism. Transcriptional changes in antioxidant cellular systems are mapped in targeted RNAi mutants and linked to the intracellular biochemical alterations that occur in gravity transitions. The goal is to chart the gene networks responsive to gravity stress.