3 research outputs found
EFFECTS OF THE NDV-GLYCOPROTEINS ON THE ELECTROPERMEABILIZATION OF LIPID BILAYERS
ABSTRACT Newcastle disease virus (NDV) is an enveloped RNA virus. Certain biological activities of the NDV are determined by two surface glycoproteins -haemaglutinin-neuraminidase (HN) and fusion-protein (F). These proteins play an active role in the viru
Membrane electropermeabilization effects of frequency and membrane surface order on liposome leakage
Liposomes containing fluorescence marke r
were exposed to an alternating electric field of 80 V
peak to peak square electric waves at diff e r e n t
frequencies 0.01, 1, and 100 kHz to perturb the liposome
permeation. The efflux of fluorescence dye after
application of the electric field was measured by
recording the fluorescence emission due to the complex
formation reaction between the fluorescence dye and
calcium ions in the bulk medium solution. Two
independent sets of experiments were conducted: 1)
calcium ions were present during electropulsation; and
2) they were added after electric field application. Two
parameters, fluorescence emission intensity and
increment of temperature of the solution in the chamber,
were studied. The effect of membrane surface order on
the fluorescence dye leakage from the liposomes wa s
studied by addition of urea at threshold concentration
before the liposomes sealed. The data demonstrate the
existence of frequency dependency window at 1 kHz.
Furthermore, the data were interpreted according to the
theory of interactions of electromagnetic fields with
highly polarized and deformed materials such as
liposome particles. The urea caused an enhancement of
the fluorescence dye leakage at frequency of 100 kHz.
This effect could be explained as a decrease of the
membrane binding rigidity due to the disordering effect
of urea on the membrane lipid surface. Our conclusion is
that the frequency and the membrane surface order are
additional parameters that influence the processes of membrane electropermeabilization