SPECTROSCOPY, IMAGING, OTHER TECHNIQUES |
Scaling Behavior in Mitochondrial Redox Fluctuations
V Krishnan Ramanujan 1, Gabriel Biener 2 and Brian Herman 3*
1 UT Health Science Center at San Antonio
2 Technion-Israel Institute of Technology, Israel
3 University of Texas Health Science Center at San Antonio
* To whom correspondence should be addressed. E-mail: hermanb{at}uthscsa.edu.
Submitted on February 15, 2006
Revised on March 7, 2006
Accepted on 8 March 2006
 |
Abstract |
|---|
Scale-invariant long range correlations have been reported in fluctuations of time-series signals originating from diverse processes such as heart beat dynamics, earthquakes, and stock market data. The common denominator of these apparently different processes is a highly nonlinear dynamics with competing forces and distinct feedback species. We report for the first time an experimental evidence for scaling behavior in NAD(P)H signal fluctuations in isolated mitochondria and intact cells isolated from the liver of a young (5 month old) mouse. Time-series data were collected by two-photon imaging of mitochondrial NAD(P)H fluorescence and signal fluctuations were quantitatively analyzed for statistical correlations by detrended fluctuation analysis and spectral power analysis. Redox [NAD(P)H / NAD(P)+] fluctuations in isolated mitochondria and intact liver cells were found to display non-random, long-range correlations. These correlations are interpreted as arising due to the regulatory dynamics operative in Krebs' cycle enzyme network and electron transport chain in the mitochondria. This finding may provide a novel basis for understanding similar regulatory networks that govern the non-equilibrium properties of living cells.
Key Words:
Mitochondria, NADH Imaging, Redox, Scaling, Twophoton imaging
