Unraveling cell processes: interference imaging interwoven with data analysis.

The paper presents results on the application of interference microscopy and wavelet-analysis for cell visualization and studies of cell dynamics. We demonstrate that interference imaging of erythrocytes can reveal reorganization of the cytoskeleton and inhomogenity in the distribution of hemoglobin, and that interference imaging of neurons can show intracellular compartmentalization and submembrane structures. We investigate temporal and spatial variations of the refractive index for different cell types: isolated neurons, mast cells and erythrocytes. We show that the refractive dynamical properties differ from cell type to cell type and depend on the cellular compartment. Our results suggest that low frequency variations (0.1-0.6 Hz) result from plasma membrane processes and that higher frequency variations (20-26 Hz) are related to the movement of vesicles. Using double-wavelet analysis, we study the modulation of the 1 Hz rhythm in neurons and reveal its changes under depolarization and hyperpolarization of the plasma membrane. We conclude that interference microscopy combined with wavelet analysis is a useful technique for non-invasive cell studies, cell visualization, and investigation of plasma membrane properties.

Study of regular intracellular and membrane processes in neurons by laser interference microscopy.

Regular fluctuations in the height of phase profile of isolated neuron were studied by laser interference microscopy. The resultant spectra of frequencies of changes in the phase profile height indicate regular local changes in the optical density and/or geometry of neurons. The frequency spectra for the central and pri-membrane regions of the cells are different.

Interference microscopy under double-wavelet analysis: a new approach to studying cell dynamics.

This Letter combines a novel experimental approach to the study of intracellular processes with a newly developed technique for multimode time-series analysis. Experiments are performed on isolated pond snail (Lymnaea stagnalis) neurons. Local variations in the cellular refractive index as detected by laser interference microscopy are related to the processes in the cell. A wavelet analysis shows the presence of several identifiable modes in the membrane and intracellular dynamics, and a double-wavelet analysis reveals nonlinear interactions between the regulatory processes in the form of mutual frequency and amplitude modulations.

[Redistribution of membrane-bound Ca2+ in neurolemma of leech Retzius-neurons during thermostimulation]. / Pereraspredelenie membranosviazannogo Ca2+ v neirolemme Retzius-neironov piiavki pri termostimuliatsii.

Changes in electrical activity, plasma membrane and inner mitochondrial membrane potentials, as well as in the content of membrane-bound calcium and NADH in identified leech ganglion neurons during thermal stimulation were studied by microelectrode and microfluorimetric methods. It was shown that thermal stimulation of skin patches from different regions of leech body causes a reversible increase in the firing rate of pacemaker neurons (Rz neurons). A decrease in the content of membrane-bound calcium in the neurolemma and NADH content in Rz neuron mitochondria, and a depolarization of inner mitochondrial membrane were also observed.