Probing single secretory vesicles with capillary electrophoresis

Area of Science:

• * Marine Biology
• * Biochemistry
• * Analytical Chemistry

Background:

• * Secretory vesicles play crucial roles in cellular communication and function.
• * Understanding the heterogeneity of vesicle contents is vital for biological processes.
• * Previous analyses often involved bulk samples, masking individual vesicle variations.

Purpose of the Study:

• * To chemically characterize individual secretory vesicles from the atrial gland of Aplysia californica.
• * To develop and apply a novel method for single-vesicle chemical analysis.
• * To investigate the heterogeneity of molecular cargo within these vesicles.

Main Methods:

• * Isolation and manipulation of single secretory vesicles using optical trapping.
• * Introduction of single vesicles into a capillary electrophoresis system.
• * Fluorescent labeling of vesicle components with naphthalene-2,3-dicarboxaldehyde.
• * Detection and analysis using laser-induced fluorescence and capillary electrophoresis separation.

Main Results:

• * Successful isolation and chemical analysis of single attoliter-volume vesicles.
• * Demonstration of distinct chemical composition variations among individual vesicles.
• * Generation of unique electropherograms for each analyzed vesicle, highlighting heterogeneity.

Conclusions:

• * The applied methodology enables precise chemical profiling of single secretory vesicles.
• * Secretory vesicles from Aplysia californica exhibit significant intra-vesicular content heterogeneity.
• * This approach provides new insights into the functional diversity of secretory vesicles.