Effects of electromagnetic fields on the motion of Euglena gracilis

Ascoli, C.; Barbi, Martina; Frediani, C.; Petracchi, D.

doi:10.1016/s0006-3495(78)85407-1

Cited by 23 publications

(13 citation statements)

References 6 publications

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“…It is well known that its motion is propelled by a long flagellum beating around the body, and it moves in a rototranslatory motion with the speed of about 100–400 μm/s. 1, 20, 21 Its body is slightly tilted with respect to the axis of the movement. 20 Considering the motion parameters of Euglena gracilis , we set the imaging frame rate at 180 fps, where we typically used 16 – 25 images to reconstruct a single high resolution image with the enhancement factor n = 4 – 5.…”

Section: Resultsmentioning

confidence: 99%

“…1, 20, 21 Its body is slightly tilted with respect to the axis of the movement. 20 Considering the motion parameters of Euglena gracilis , we set the imaging frame rate at 180 fps, where we typically used 16 – 25 images to reconstruct a single high resolution image with the enhancement factor n = 4 – 5. This lengths of the sequence represent the image of the cell during approximately 0.1 seconds, which typically gives 10–40 μm displacement of the microorganisms within the sequence and makes it safe to assume that the internal sub cellular structures are static and the rotation perpendicular to the axis of translation is negligible.…”

Section: Resultsmentioning

confidence: 99%

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On-chip continuous monitoring of motile microorganisms on an ePetri platform

et al. 2012

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Self-imaging Petri dish platforms with microscopy resolution, which we term as ePetri, can significantly streamline cell cultures and/or other longitudinal biological studies. In this paper, we demonstrate high resolution imaging and long term culture of motile microorganisms in a specialized ePetri platform by taking advantage of the inherent motion. By applying a superresolution algorithm to a set of low-resolution images of the microorganisms as they move across the sensing area of a Complementary metal Oxide Semiconductor (CMOS) image sensor chip, we can render an improved resolution image of the microorganisms. We perform longitudinal study of Euglena gracilis cultured in an ePetri platform and image based analysis on the motion and morphology of the cells. As a miniaturized and automated culture monitoring platform, this ePetri technology can greatly improve studies and experiments with motile microorganisms.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

On-chip continuous monitoring of motile microorganisms on an ePetri platform

et al. 2012

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“…Different theoretical approaches have been employed to interpret LFO. The approach assuming the minimization of the free energy of the suspended cell has been proven experimentally . Here, we apply a second approach, which compares the different torques being induced around the three principal axes of the CRBC model .…”

Section: Discussionmentioning

confidence: 99%

Combined detection of AC‐electrokinetic effects: Experiments with three‐axial chicken red blood cells

et al. 2018

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Dielectrophoresis (DEP), electrorotation (ROT), and electro-orientation were used for the dielectric spectroscopy of nucleated three-axial chicken red blood cells (CRBCs). Because the different AC-electrokinetic effects are not mutually independent, their DEP and ROT spectra were combined in ranges separated by the reorientation of the CRBCs in the inhomogeneous linear DEP and circular ROT fields. This behavior can be qualitatively described by a single-shell ellipsoidal model. Whereas in linear fields, the maximum of the Clausius-Mossotti factor along the three axes determines the orientated axis, in circular fields, the minimum of the factor determines the axis perpendicularly orientated to the field plane. Quantitatively, it has not been possible to find a consistent parameter set for fitting the DEP and ROT spectra, as well as the reorientation frequencies. Our ellipsoidal CRBC standard model had semiaxes of a = 7.7 μm, b = 4.0 μm, and c = 1.85 μm, a relative permittivity of 35 to 45 and conductivity of 0.36 to 0.04 S/m for the cytoplasm, combined with a specific capacitance of 10 to 14 mF/m and a conductivity of 3500 S/m for the cell membrane. The fits in different external conductivity ranges between external conductivities of 0.015 and 1.0 S/m were improved when the membrane capacitance was changed between 4 to 25 mF/m depending on the method used. A similar transition was reflected in the effective properties of a three-shell spherical model containing an internal membranous sphere with the geometry of the CRBC nucleus. Our findings suggest that the simultaneous interpretation of various AC-electrokinetic spectra is a step toward the dielectric fingerprinting of biological cells.

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“…The electrodes used to apply the orienting field were placed under the chamber containing the sample. The 2-MHz field orients the cells parallel to the field (Ascoli et al, 1978). To achieve a good orientation by using low field intensities, the cells were suspended in a medium with a low electrical conductivity (-10-3 mho/m); no damage to the cells was observed.…”

Section: Methodsmentioning

confidence: 99%

“…These favorable experimental conditions (unidirectional motion, appropriate scattering angles) were obtained by exploiting a qualitative knowledge of E.g. motion and of the angular distribution of the scattered light intensity, and by using the Euglena orientation feature in an alternating electric field; (Teixeira-Pinto et al, 1960;Griffin and Stowell, 1966;Ascoli et al, 1978). A similar experimental approach was followed by Dubois et al (1974) in measuring the speed distribution of human spermatozoa moving in capillary tubes filled with cervical mucus.…”

Section: Introductionmentioning

confidence: 99%

Measurements of Euglena motion parameters by laser light scattering

Ascoli¹,

Barbi²,

Frediani³

et al. 1978

Biophysical Journal

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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.

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Effects of electromagnetic fields on the motion of Euglena gracilis

Cited by 23 publications

References 6 publications

On-chip continuous monitoring of motile microorganisms on an ePetri platform

On-chip continuous monitoring of motile microorganisms on an ePetri platform

Combined detection of AC‐electrokinetic effects: Experiments with three‐axial chicken red blood cells

Measurements of Euglena motion parameters by laser light scattering

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