03/30/2026
By Kwok Fan Chow

The Kennedy College of Science, Department of Chemistry, invites you to attend a Ph.D. Dissertation defense by Hatim M. Abulola entitled “Real-Time Imaging of Calcium Transients in Excitable and Non-Excitable Cells: An Approach to the Study of Spatiotemporal Dynamics.”

Date: Tuesday, April 7, 2026
Time: 9 a.m.
Location: Via Zoom

Committee:

  • Advisor: Matthew Gage, Ph.D., Department of Chemistry, University of Massachusetts Lowell
  • Nicolai Konow, Ph.D., Department of Biological Sciences, University of Massachusetts Lowell
  • Jin Xu, Ph.D., Department of Chemistry, University of Massachusetts Lowell
  • Michael B. Ross, Ph.D., Department of Chemistry, University of Massachusetts Lowell

Abstract:
Calcium (Ca2+) is a key secondary messenger that regulates cellular processes, including muscle contraction, immune function, neurotransmission, and differentiation. Ca2+ dynamics are highly cell-specific, shaping how cells respond to physiological and pathological stimuli. Despite extensive studies, many aspects of Ca2+ signaling dynamics remain unclear. This dissertation investigates Ca2+ dynamics in two different systems: skeletal muscle fibers (excitable) and B-cells (non-excitable).

Using fluorescence microscopy and membrane-permeable calcium indicators, intracellular Ca2+ responses were investigated in B-cells following stimulation with soluble antibody or through immune synapse formation. Soluble antibody stimulation resulted in transient Ca2+ elevations, with an initial increase from intracellular stores (~400 nM) followed by extracellular influx, reaching ~600 nM. In contrast, immune synapse stimulation resulted in sustained Ca2+ elevations. Ca2+ waves originated from localized cellular domains, suggesting ordered clustering of Ca2+ channels. Additionally, BCR capping experiments revealed increased BCR membrane intensity after stimulation.

In skeletal muscle fibers, Ca2+ transients were measured in mice with different genotypes, revealing differences in Ca2+ amplitude, decay kinetics, and propagation behavior. Both Thalassemia and 129SV skeletal muscle fibers exhibited distinct features in Ca2+ dynamics compared to C57 fibers. However, the relative distributions of strong, intermediate, and weak peak events were broadly similar across genotypes, indicating conserved patterns of Ca2+ release despite differences in overall dynamics.

Together, these studies provide a comparative view of Ca2+ signaling in excitable and non-excitable cells, highlighting shared organizational principles and cell-specific differences in amplitude and propagation. The quantitative analyses and mechanistic observations presented here provide a framework for future studies comparing Ca2+ signaling in healthy and diseased cells.

All interested students and faculty members are invited to attend.