Usuy David León Tolosa

| NeuroTree  |  udleont(a)unal.edu.co  |  ORCID  |  GitHub  | 

Researcher and educator with two years of experience, specializing in microscopy, open science, and open-source software. Dedicated to investigating the biological mechanisms driving pattern formation and the regeneration of complex 3D tissues and structures

Education
Jan 2016 – Dec 2022
Bachelor in Biology, National University of Colombia, Bogotá, DC, Colombia.
  • 2023 University Award Best Bachelor Thesis of the Year
  • 2023 National Award Top Undergraduate Performance University-Level Saber Pro National Exam
Research Experience
May 2023-Dec 2024
Faculty Assistant, University of Maryland, College Park, MD, USA.
Angueyra's Laboratory
  • Characterized effects of thrb modulation on photoreceptor subtypes of Astatotilapia Burtoni (preliminary NSF grant data)
  • Induced CRISPR mutagenesis on Foxq2 transcription factor; sparse neuron labeling to evaluate synaptic connectivity in Danio rerio
  • Recorded electroretinograms and optokinetic responses during early visual development of Astatotilapia Burtoni
  • Explored horizontal cell diversity across species using DII staining and confocal microscopy (Snakes, Geckos, Cichlids, Mongolian Gerbil, Zebrafish)
  • Assembled a custom electrophysiology rig and multi-wavelength stimulator for ERG recordings
May 2021-July 2023
Research Assistant, National University of Colombia, Bogota DC.
Neurophysiology Research Group
  • Established protocols to isolate functional photoreceptors from schmidtea mediterranea planaria for patch clamp and calcium imaging
  • Labeled phototransduction cascade elements by immunohistochemistry on planarian ocelli
  • Skilled in planarian ocelli dissection and tissue dissociation; culture maintenance
May 2020-Sep 2020
Research Trainee, University of Pennsylvania, Philadelphia.
Ma's Laboratory
  • Applied machine learning (DeepLabCut) to analyze behavioral effects from optogenetic manipulations in mice ventral striatum.
  • Co-authored a review on olfactory and non-olfactory brain network connections
Jan 2019-Dec 2020
Research Trainee, National University of Colombia, Bogotá DC.
Neurophysiology Research Group
  • Trained in cellular electrophysiology, immunocytochemistry, chicken eye dissection, electrophoresis, Western blot, and neuroblastoma cell culture
Feb 2018-Dec 2018
Research Trainee, National University of Colombia, Bogotá DC.
Protein Research Group
  • Purified lectin protein from Salvia bogotensis using afinity t chromatography to test insecticidal activity against Tecia solanivora
Publicaciones
  • León, U., Forero, J. (2025). El Solar Observatory of Bacata: New Archeo-Astronomical Perspectives in the historical center of Bogota eSPECTRA. Revista del Observatorio Nacional de Colombia (On review).
  • Bhattarai, J.P., Etyemez, S., Jaaro-Peled, H., Janke, E., León Tolosa, U.D., Kamiya, A., Gottfried, J.A., Sawa, A., Ma, M. (2021). Olfactory modulation of the medial prefrontal cortex circuitry: implications for social cognition. Seminars in Cell and Developmental Biology
Teaching Experience
Jan 2024-May 2024
<Teaching Assistant, University of Maryland, College Park, MD, USA Neurophysiology Laboratory 405
  • Supervised weekly 4-hour labs (~20 students) on extracellular/intracellular electrophysiology with crayfish, crickets, and worms
  • Guided students in experiment design and poster presentations of pharmacology and sensory data
Feb 2017-Dec 2018
Voluntary Teacher Colegio Distrital 20 de Julio, Bogota DC, Colombia
Pre-university course
  • Mentored low-resource community students preparing them for National University entrance exam
Presentations and Posters
  • Leon, U., Forero, J. (2025). El Observatorio Solar de Bacatá: Nuevas perspectivas arqueo astronómicas en el centro histórico de Bogotá. V Workshop de Astronomia de los Andes, Universidad de Nariño, Pasto. (Principal presenter)
  • Leon, U., Angueyra, J. (2024). Waiting for godot? Unveiling the rules for synaptic connectivity of horizontal cells. Mid Atlantic Zebrafish Meeting (MARZ), Rutgers University, NJ. (Principal presenter)
  • Leon, U., Ma, M. (2020). Contribution of the olfactory system to social cognition in mice. Undergraduate Internship Program, University of Pennsylvania, Philadelphia, PA. (Principal presenter)
  • Puerto, P., Leon, U., Zuluaga, M., Gomez, P. (2023). Planaria eye as a study model of phototransduction. XIII Seminario Nacional de Neurociencia (COLNE), Cali, Valle del Cauca. (Principal presenter)
Technical skills
  • Microscopy: Light sheet, Confocal live, and Expansion microscopy
  • Electrophysiology: Patch-clamp, ERG, Calcium imaging (GCamp6, Fluo4AM)
  • Molecular Bio: CRISPR, PCR, cell transfection, Western blot
  • Staining: Lipid tracing (DII), Golgi staining, Immunocytochemistry
Software and coding
  • Software: Python, Bash, FIJI/ImageJ, μManager, Nikon Elements, Zeiss Zen, DeepLabCut, Prusa Slice
  • Tools: Linux, Inkscape, OpenSCAD, Git, LaTeX
  • Hardware: 3D Printing, Arduino, Raspberry Pi, Basic circuits Soldering
Languages
Spanish
C2
English
C1
German
A2
References
Juan Angueyra, M.D., Ph.D.
Assistant Professor, Department of Biology, University of Maryland – College Park
angueyra@umd.edu
María del Pilar Gómez, M.D., Ph.D.
Associate Professor, Department of Biology, National University of Colombia
mpgomezco@unal.edu.co
Karen Carleton, Ph.D.
Full Professor, Department of Biology, University of Maryland - College Park
kcarleto@umd.edu
Minghong Ma, Ph.D.
Full Professor, Department of Biology, University of Maryland - College Park
minghong@pennmedicine.upenn.edu
Enrico Nasi Lignarolo, Ph.D.
Full Professor, Genetics Institute, National University of Colombia
enasil@unal.edu.co