Dielectrophoretic behaviour of Saccharomyces cerevisiae: effect of cations and detergents

Lopez, MaCarmen

doi:10.1016/0378-1097(84)90240-4

Cited by 17 publications

(5 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dielectric and electrorotation properties of S. cerevisiae have also been extensively investigated. Such studies include the effects of chemical exposure (Lopez et al 1984, 1985, Geier et al 1987, Arnold et al 1988a, b, Stoicheva et al 1989, Pauli et al 1993, Zhou et al 1996, differences between viable and non-viable yeast (Crane and Pohl 1968, Huang et al 1992 and changes in dielectric properties during batch culture (Arnold et al 1989, Kell et al 1990.…”

Section: Introductionmentioning

confidence: 99%

Automatic cell electrorotation measurements: studies of the biological effects of low-frequency magnetic fields and of heat shock

1998

View full text Add to dashboard Cite

A computer-aided automatic imaging technique has been developed for measuring the electrorotation spectra of up to 256 particles at the same time. This offers advantages over the conventional manual method, especially when rapidly acquired statistical data are necessary in investigations of the response of cells or test beads to chemical exposure, for example. We have applied this technique to investigate the biological effects of heat shock and low-frequency EM fields reported by others for yeast cells. Although heat shock effects were observed, no changes of the electrorotational behaviour could be detected after exposing the cells to 50 Hz, 8 and 80 microT fields. Although this does not rule out the possibility that the cells were influenced by the magnetic fields, it does limit the number of possible physicochemical changes that might have occurred to their cell walls and membranes.

show abstract

Section: Introductionmentioning

confidence: 99%

Automatic cell electrorotation measurements: studies of the biological effects of low-frequency magnetic fields and of heat shock

1998

View full text Add to dashboard Cite

show abstract

“…(22,26,27). Conversely, Lopez et aL (7) have measured viability of yeast cells subjected to AC fields and have noted a correlation between the viability of the cells and number of cells aligning.…”

Section: Response Of Protoplasts To Electrofusion Parameters Conditiomentioning

confidence: 99%

Behavior and Viability of Tobacco Protoplasts in Response to Electrofusion Parameters

Saunders

Roskos²,

Mischke³

et al. 1986

Plant Physiol.

View full text Add to dashboard Cite

This investigation examines responses of protoplasts in a systematic and quantitative way to the various electrical treatments used to achieve electrofusion and their individual and cumulative effect on protoplast viability. Mesophyll and cell suspension protoplasts from two species of the same genera, Nicotiana tabacum and N. rustica var brasilia were used in these experiments. Optimal frequencies for alignment of tobacco protoplasts were between 500 kilohertz and 2 megahertz at 100 volts per (22,24). For plant cells, typical procedures involve three steps; alignment of protoplasts with an AC field, disruption of contiguous membranes with a brief DC pulse, and fusion of the protoplasts (1,15,22,24). Much of the emphasis in previous research has been directed toward the modification of the DC pulse to achieve maximum fusion rates while little data has been presented on the effects of both the AC fields and the DC pulses on cell viability. Indeed, only recently have published reports appeared on the successful regeneration of shoots from hybrids of electrically fused protoplasts (2, 4). We report here the effects of AC and DC currents, separately and in combinaton, on the viability and integrity of protoplasts and on the movement of protoplasts.MATERIALS AND METHODS Plant Material. Nicotiana rustica var brasilia and N. tabacum cv MD 872 were grown under greenhouse conditions and harvested 70 to 90 d after germination. One week prior to harvest the plants were transferred to an environmental growth chamber that maintained a 12 h day length at 23°C. Shoots and cell suspensions of N. tabacum cv Connecticut 'John Williams Broadleaf' were cultured in vitro as described by Owens (11) and Uchimiya and Murashige (19), respectively.Preparation of Protoplasts. Protoplasts from greenhouse grown plants were isolated from mature mesophyll leaf tissue with 1% (w/v) Macerase3 (300 units/g) and 2% (w/v) Cellulysin (10,000 units/g) in 50 mm Mes-NaOH buffer (pH 5.7) with 0.6 M mannitol as described previously (16). Protoplasts were isolated from tissue culture by an adaptation of the methods of Owens (10) and Lin (6). One g of suspension cells in 40 ml of 0.15% Cellulysin, 1% rhozyme HP-150, and 0.05% Driselase was incubated for 4 h at 30°C with shaking at 50 rpm. All enzymes were desalted and dissolved in a solution of 0.7 M mannitol, 9.25 mM CaCl2, and 0.44 mm Ca(H2PO4)2 adjusted to pH 5.7. Protoplasts were harvested by centrifugation (100g for 3 min) and resuspended in 4 ml of 16% (w/v) Ficoll in 0.7 M mannitol. Four ml each of 14% (w/v) and 12% (w/v) Ficoll in 0.7 mannitol 3 Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by the United States Department of Agriculture, and does not. imply its approval to the exclusion of other products or vendors that may also be suitable.

show abstract

“…age the cell membrane and affect the dielectrophoretic yield as described previously (7). The results are shown in Table II.…”

Section: Biophysical Journal Volume 48 1985mentioning

confidence: 81%

“…In previous works we analyzed the dielectrophoretic behavior of yeast cells with different shapes and their response to several physical and biological parameters (Iglesias et al [6]; Lopez et al [7] ). We have also shown that some of the properties of yeast cells are similar to those of macromolecular suspensions, while others depend on the metabolic state of the cells (7,8).…”

Section: Introductionmentioning

confidence: 99%

Orientation of Schizosaccharomyces POMBE Nonliving Cells under Alternating Uniform and Nonuniform Electric Fields

Iglesias¹,

Lopez²,

Santamaría³

et al. 1985

Biophysical Journal

View full text Add to dashboard Cite

When nonliving cells of Schizosaccharomyces pombe were subjected to the action of alternating uniform and nonuniform electric fields, two types of orientation were produced. The first one, with its longest axis parallel to the field lines, is similar to that obtained with living cells. The second, perpendicular to the direction of the field, is produced for relatively high frequencies and low conductivities; this probably takes place when the conductivities of the external and internal media (cell cytoplasm) become equal. A mixed cell population is produced in a discrete interval of the parameters used. Our results provide direct evidence that cell alignment does not depend on the physiological state of the cells.

show abstract

Dielectrophoretic behaviour of Saccharomyces cerevisiae: effect of cations and detergents

Cited by 17 publications

References 9 publications

Automatic cell electrorotation measurements: studies of the biological effects of low-frequency magnetic fields and of heat shock

Automatic cell electrorotation measurements: studies of the biological effects of low-frequency magnetic fields and of heat shock

Behavior and Viability of Tobacco Protoplasts in Response to Electrofusion Parameters

Orientation of Schizosaccharomyces POMBE Nonliving Cells under Alternating Uniform and Nonuniform Electric Fields

Contact Info

Product

Resources

About