Interference microscopy in cell biophysics. 2. Visualization of individual cells and energy-transducing organelles.

The coherent phase microscopy (CPM) provides a convenient and non-invasive tool for imaging cells and intracellular organelles. In this article, we consider the applications of the CPM method to imaging different cells and energy-transducing intracellular organelles (mitochondria and chloroplasts). Experimental data presented below demonstrate that the optical path length difference of the object, which is the basic optical parameter measured by the CPM method, can serve as an indicator of metabolic states of different biological objects at cellular and subcellular levels of structural organization.

Interference microscopy in cell biophysics. 1. Principles and methodological aspects of coherent phase microscopy.

The purpose of our tandem publications is to review the applications of the coherent phase microscopy to cell biophysics. In this article, we briefly consider the fundamentals and methodological aspects of the coherent phase microscopy (CPM). One of important advantages of this method is a high sensitivity of CPM images to changes in physical-chemical properties of biological samples.

The metabolic component of cellular refractivity and its importance for optical cytometry.

Initially, it has been shown that the phase thickness and refractivity (the latter interpreted as the difference of the refractivity indices of an object and surrounding medium) depend on the functional state of mitochondria. The refractivity of various objects decreased in response to energy depletion. This dependence was then demonstrated for other biological objects such as cyanobacteria, chloroplasts and human cells.

Coherent phase microscopy in cell biology: visualization of metabolic states.

Visualization of functional properties of individual cells and intracellular organelles still remains an experimental challenge in cell biology. The coherent phase microscopy (CPM) provides a convenient and non-invasive tool for imaging cells and intracellular organelles. In this work, we report results of statistical analysis of CPM images of cyanobacterial cells (Synechocystis sp.

Mitochondria optical parameters are dependent on their energy state: a new electrooptical effect?

The membrane potential of mitochondria determines, to a large extent, their functional state and the response to the changing conditions of the environment. A correlation was found between the changes in the optical characteristics of isolated mitochondria and the composition of the incubation medium, which determines the potential of the inner mitochondrial membrane. The measurements performed by the method of coherent phase microscopy made it possible to establish a linear dependence of the phase height on the value of the membrane potential and to calculate the electrooptical constant, K approximately equal to (3-4) x 10(-7) m/V.

A dynamic phase microscopic study of optical characteristics of individual chloroplasts.

Dynamic phase microscopy (DPM) allows the monitoring of optical path difference (or phase height), h(x,y,t) approximately integraln(x,y,z,t)dz, an integral refractive index projection of the medium, n(x,y,z,t), in optically transparent biological specimens at high spatial and temporal resolutions. In this study, DPM was used for the analysis of fluctuations in the optical characteristics of individual bean chloroplasts in various metabolic states. A "phase image" of an individual chloroplast, which represents a three-dimensional plot of the "phase height", was obtained for the first time, and the frequency spectra of the fluctuations of h(x,y,t) were investigated.