Measurements of Euglena motion parameters by laser light scattering

Abstract

Measurements of Euglena gracilis motion parameters have been performed by the spectral analysis of the scattered laser light. Samples were oriented by a radiofrequency field to obtain easily interpretable spectra. Cell rotation frequency and flagellar beating frequency distributions were obtained from the homodyne spectra, whereas the Doppler lines obtained at small observation angles by heterodyne detection yielded the swimming speed distributions. We discuss the broadening of the heterodyne spectra at large angles of observation. An application of this method to the study of the photo-kinetic effect is also described.

Evaluation of Growth Characteristics of <I>Euglena gracilis</I> for Microalgal Biomass Production Using Wastewater

“…Although euglenid is classified as both animal (Häder and Liu, 1990) and plant (Chang et al, 1981), the classification of Euglenophyceae in Euglenozoa was adopted in this research according to the classification by the National Institute for Environmental Studies. This species is an oval-shaped single cell flagellate (Ascoli et al, 1978) with a high growth rate (Mahapatra et al, 2013) and can grow under both autotrophic and heterotrophic conditions because it is a mixotrophic alga (Takeyama et al, 1997). It is considered to be potentially useful for biomass energy, because of the production ability of wax esters combined with fatty alcohols and fatty acids (Inui et al, 1982).…”

Is Information a Sufficient Basis for Cognition? Part 1: Critique of Dretske’s Approach

“…For instance, as the study of the movement of the Euglena in relation to light variations has proven, rather fuzzy and analogical rules regulate its movement (speed variation, flagellar beating frequency, orientation towards light) and because of the direct connection of the sensing structure to the motor one, this can only be due to a fuzzy feeling of the light conditions (e.g. it is dark, the light is good, the light is too bright) (Ascoli, 1978;Richter et al, 2002). Probably if the light sensing of the Euglena were not fuzzy its behavior would not be appropriated.…”

Rhodopsin: A Photopigment for Phototaxis in Euglena gracilis

“…The frequency of rotation is 2 Hz (Ascoli et al, 1978). This configuration of stigma, swelling, and flagellum, then, can be considered a simple but complete visual system.…”