Electrorotation of single yeast cells at frequencies between 100 Hz and 1.6 GHz.

AUTOR(ES)

Hölzel, R

RESUMO

The determination of complete electrorotation spectra of living cells has been made possible by the development of a quadrature generator and an electrode assembly that span the frequency range between 100 Hz and 1.6 GHz. Multiple spectra of single cells of the yeast Saccharomyces cerevisiae have been measured at different medium conductivities ranging from 0.7 to 550 microS cm-1. A spherical four-shell model was applied that simulated the experimental data well and disclosed the four-layer structure of the cell envelope attributed to the plasma membrane, the periplasmic space, and a thick inner and a thin outer wall region. Below 10 kHz an additional rotation effect was found, which changed its direction depending on the ionic strength of the medium. This is supposed to be connected with properties of the cell surface and its close vicinity. From the four-shell simulation the following physical properties of cell compartments could be derived: specific capacitance of plasma membrane (0.76 microF cm-2), periplasmic space (0.5 microF cm-2), and outer wall region (0.1 microF cm-2). The conductivity of cytoplasm, plasma membrane, and inner wall region were found to vary with medium ionic strength from 9 to 12 mS cm-1, 5.8 nS cm-1 to approximately 50 nS cm-1, and 6 microS cm-1 to 240 microS cm-1, respectively.

Documentos Relacionados

• Dielectric behavior of wild-type yeast and vacuole-deficient mutant over a frequency range of 10 kHz to 10 GHz.
• Crystal structure of a fibrillarin homologue from Methanococcus jannaschii, a hyperthermophile, at 1.6 Å resolution
• An improved method for recovering intact pulsed field gel purified DNA, of at least 1.6 megabases.
• Crystal structure of desheptapeptide(B24–B30)insulin at 1.6 Å resolution: Implications for receptor binding
• Comparative study of the effect of 100 Hz and 16 Hz pulse repetition frequency 1 MHz ultrasound rat fibula fracture treatment