Problems Associated With the Study of Cellular Oscillations

Abstract

Data from the article by Brodsky et al. (2000) have been examined in order to confirm that the fluctuations they report are not random but have a rhythmic basis, thereby verifying their conclusions regarding the existence of periodicity in protein synthesis. Reasons are outlined why oscillations should be expected in all cellular biochemical studies. Associated practical problems are briefly discussed together with comments on the validity and value of less rigorous methods of analysis. The subject of aliasing is raised as justification for doubting the validity of much published data, especially where periodicity has not been suspected. The existence of oscillations indicates the need for a thorough re-evaluation of our understanding of cell biochemistry.

Fourier-based spatial mapping of oscillatory phenomena in fungi

“…In practice, the risk of aliasing artifacts increases markedly when the observed frequencies are close to this limit (Gilbert and Ferreira, 2000), so we preferred to use a sampling frequency several fold higher than the observed frequency. For example, the sampling integration period was 1 h for [ 14 C]-AIB transport in P. velutina and C. puteana, with a temporal smoothing of 5 h, in comparison to an oscillation period of $14 h and $25 h, respectively.…”

“…When there is no explicit spatial dimension to the oscillation, analysis of the rhythm can be captured by the average response of the system and presented as a simple graph of the time-series (Priestley, 1981;Diggle, 1990;Smith, 1997;Chatfield, 2004), provided the sampling interval itself does not introduce aliasing artifacts (Gilbert and Ferreira, 2000). However, visualisation and analysis of oscillatory systems in two (or even three) dimensions is more challenging (see for example Aon et al, 2007).…”

The Pollen Tube Oscillator: Integrating Biophysics and Biochemistry into Cellular Growth and Morphogenesis

“…Nevertheless, it is still unknown if pollen tubes have one or more oscillatory sub-systems, and how each regulatory point may influence the whole system. Measurements will have to be done as to minimise the influence of external factors to avoid triggering of any kind of periodic response, as well as data representation must be optimised (Gilbert and Ferreira 2000).…”

Relationship of demethylation processes to veratric acid concentration and cell density in cultures of Rhodococcus erythropolis

“…The auto-oxidation rate of pyrogallol was measured as absorbance changes at 315 nm (Marlkund and Marklund, 1974) at 30 (C. As suggested by Gilbert and Ferreira (2000), data were presented without error bars, as they may obscure the underlying curves, especially for high frequency rhythms. Briefly, 0.2 ml of each sample was mixed with 0.1 ml of 5 mM pyrogallol and adjusted to a final volume of 3 ml with 50 mM Tris-HCl buffer, pH 8.5, containing 0.1 mM EDTA.…”

“…Oscillation is a significant biological phenomenon, underlying cell function, properties and behaviour (Gilbert and Ferreira, 2000;Gilbert and Llyod, 2000).…”