Honors & Awards
EMBO Short Term Fellowship, European Molecular Biology Organization (November 2016)
'Hermanas in STEM' Proposal awarded funding, Diversity Improvement Funds (VPGE), Stanford University (2015)
Bio-X Graduate Fellowship, Stanford Bio-X, Stanford University (2014-2015)
ADVANCE Fellow, Stanford University (2013)
Professional Affiliations and Activities
Co-President, Stanford Hermanas in STEM (2015 - Present)
Biology Liaison, Vice Provost for Teaching and Learning (2014 - 2016)
International Student Advocate, BioAIMs (2015 - 2016)
Career Development Chair, BioAIMs (2014 - 2015)
Lucy O'Brien, Doctoral (Program)
Long-term live imaging of the Drosophila adult midgut reveals real-time dynamics of division, differentiation, and loss.
Organ renewal is governed by the dynamics of cell division, differentiation, and loss. To study these dynamics in real time, we present a platform for extended live imaging of the adult Drosophila midgut, a premier genetic model for stem cell-based organs. A window cut into a living animal allows the midgut to be imaged while intact and physiologically functioning. This approach prolongs imaging sessions to 12-16 hours and yields movies that document cell and tissue dynamics at vivid spatiotemporal resolution. Applying a pipeline for movie processing and analysis, we uncover new, intriguing cell behaviors: that mitotic stem cells dynamically re-orient, that daughter cells use slow kinetics of Notch activation to reach a fate-specifying threshold, and that enterocytes extrude via ratcheted constriction of a junctional ring. By enabling real-time study of midgut phenomena that were previously inaccessible, our platform opens a new realm for dynamic understanding of adult organ renewal.
View details for DOI 10.7554/eLife.36248
View details for PubMedID 30427308
Role of Metal Ions on the Activity of Mycobacterium tuberculosis Pyrazinamidase
AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE
2012; 87 (1): 153-161
Pyrazinamidase of Mycobacterium tuberculosis catalyzes the conversion of pyrazinamide to the active molecule pyrazinoic acid. Reduction of pyrazinamidase activity results in a level of pyrazinamide resistance. Previous studies have suggested that pyrazinamidase has a metal-binding site and that a divalent metal cofactor is required for activity. To determine the effect of divalent metals on the pyrazinamidase, the recombinant wild-type pyrazinamidase corresponding to the H37Rv pyrazinamide-susceptible reference strain was expressed in Escherichia coli with and without a carboxy terminal. His-tagged pyrazinamidase was inactivated by metal depletion and reactivated by titration with divalent metals. Although Co(2+), Mn(2+), and Zn(2+) restored pyrazinamidase activity, only Co(2+) enhanced the enzymatic activity to levels higher than the wild-type pyrazinamidase. Cu(2+), Fe(2+), Fe(3+), and Mg(2+) did not restore the activity under the conditions tested. Various recombinant mutated pyrazinamidases with appropriate folding but different enzymatic activities showed a differential pattern of recovered activity. X-ray fluorescence and atomic absorbance spectroscopy showed that recombinant wild-type pyrazinamidase expressed in E. coli most likely contained Zn. In conclusion, this study suggests that M. tuberculosis pyrazinamidase is a metalloenzyme that is able to coordinate several ions, but in vivo, it is more likely to coordinate Zn(2+). However, in vitro, the metal-depleted enzyme could be reactivated by several divalent metals with higher efficiency than Zn.
View details for DOI 10.4269/ajtmh.2012.10-0565
View details for Web of Science ID 000306153500026
View details for PubMedID 22764307
View details for PubMedCentralID PMC3391041