Mass spectrometry imaging of mating Tetrahymena show that changes in cell morphology regulate lipid domain formation

Abstract

Mass spectrometry imaging has been used here to suggest that changes in membrane structure drive lipid domain formation in mating single-cell organisms. Chemical studies of lipid bilayers in both living and model systems have revealed that chemical composition is coupled to localized membrane structure. However, it is not clear if the lipids that compose the membrane actively modify membrane structure or if structural changes cause heterogeneity in the surface chemistry of the lipid bilayer. We report that timeof-flight secondary ion mass spectrometry images of mating Tetrahymena thermophila acquired at various stages during mating demonstrate that lipid domain formation, identified as a decrease in the lamellar lipid phosphatidylcholine, follows rather than precedes structural changes in the membrane. Domains are formed in response to structural changes that occur during cellto-cell conjugation. This observation has wide implications in all membrane processes.lipid domains | membranes | phosphatidylcholine

Improving the Molecular Ion Signal Intensity for In Situ Liquid SIMS Analysis

“…Dipalmitoylphosphatidylcholine (DPPC) is one of the phospholipid molecules that has been extensively studied using ToF-SIMS [38][39][40]. The most characteristic peak of DPPC is the m/z 184 signal, [C 5 H 15 NO 4 P] + , which represents the head group of a DPPC molecule.…”

3D Imaging of TiO2 nanoparticle accumulation in Tetrahymena pyriformis

“…Previous studies have focused on changes in lipid composition during cellular events such as mating [27] and cell division. [28] Ostrowski et al showed that the conjugation site of two mating Tetrahymena had an increased 2-aminoethylphosphonolipid (2-AEP)/phosphatidylcholine (PC) ratio indicating an increase in conical shaped lipids that are associated with high membrane curvature.…”

Membrane Dynamics at the Nuclear Exchange Junction during Early Mating (One to Four Hours) in the Ciliate Tetrahymena thermophila

“…Previous studies demonstrated replacement of cylindrical lipid species at the exchange junction with nonlamellar species that can support tight curvature during conjugation (37,38). The margins of exchange junction pores and, later, the tubular curtain they transform into represent expanding regions of tight membrane curvature.…”