[Picosecond fluorometry of Rhodopseudomonas sphaeroides strain 1760-1 bacteria].
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Bacterial Chromatophores↗
Biomedical subjects
V Z Pashchenko
Publications and source records attributed to V Z Pashchenko.
[Study of the nature of regulation of potential-dependent channels by Raman spectroscopy].
The light scattering spectra of frog somatic nerves during excitation, its block by tetrodotoxin and at different Ca2+ and H+ extracellular concentrations have been investigated. In all cases changes were observed in the C40-carotenoid peaks enhanced by the resonance Raman effect. These changes can be explained by transient carbon-carbon bond equalization of the polyene chain. The mechanism of regulation of Na-channel function by "potential-sensor" in relation to the excitable membrane was discussed.
Action Potentials↗
[The role of the state of protein-lipid interactions in stimulated membranes in the conformation of C40-carotenoids].
It was shown by Raman spectroscopy that conformation of carotenoid in the frog nerve membranes at rest and at propagation of rhythmic excitation depends on the state of protein-lipid interaction modified by exposition of the nerve in solution with trypsin, alpha-chymotrypsin, urea, glutaraldehyde, SH-reagents, isopropanol and system "Fe-ascorbate". It is suggested that the level of the protein-lipid interactions in excitable membranes with the intramembrane potential determines C40-carotenoid conformation at the propagation of rhythmic excitation by he nerve.
Animals↗
[Study of potential-dependent changes in the conformation of the beta-carotene molecule using combination scattering spectroscopy].
It has been found by Raman spectroscopy that conformational changes of beta-carotene at liposomal membrane are potential-dependent. Changes of K+ or Ca+ gradient on the liposome membrane pressed the polyene chain of beta-carotene. A mechanism of potential-dependent carotenoid conformational changes in the regulation of "antenna" or "potential sensor" in biomembrane was discussed.
Carotenoids↗
[Dynamics of electronic excitation in the photosynthetic pigment apparatus].
The fluorescence lifetime and quantum yield as a function of single picosecond laser pulse intensity were experimentally studied in chloroplasts and subchloroplast particles. The intensity of laser pulse were changed from 3 x 10(12) to 10(17) photon/cm2. To explain experimental results it was considered that energy transport in the light harvesting antenna occurs by localised excitons. Parameters governing dynamic of electronic excitation within light harvesting antenna were determined. The diffusion coefficient was found to be 2 x 10(-2) cm2sec-1; diffusion length L greater than or equal to 900 A, energy transfer probability W approximately 10(12)sec-1. The rate of constant of energy transfer from light harvesting antenna to PS1 and PS2 reaction centers and effectiveness of the exciton capture by the PS2 reaction center were estimated.
Chloroplasts↗
[Excitation profile of nerve carotenoids in stimulation and block].
Using resonance Raman spectroscopy (RRS) nerve carotenoids excitation profile at electric stimulation and block was investigated. It was found changes in intensities, position and relation 1526 and 1160 cm-1 RRS lines at stimulation and tetrodotoxin (10(-7) M) block. During rhythmic excitation two phase of dynamic of relation 1526/1160 cm-1 was found. The role of electrochromic effect on nerve carotenoids conformation at electrostimulation was discussed.
Animals↗