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N N Vsevolodov

Publications and source records attributed to N N Vsevolodov.

8 recordsLinked to original sources
PubMed1995

4-Keto-bacteriorhodopsin films as a promising photochromic and electrochromic biological material.

Photochromic and electrochromic spectral properties of 4-keto-bacteriorhodopsin (4-keto-BR) embedded in a polymer matrix were studied. The light-induced spectral changes were found to be similar to those for 4-keto-BR in suspension, but the duration of the photocycle is substantially longer (up to ten of h). Application of a constant electric field induces a bathochromic shift of the main absorption band, the amplitude of the field-induced spectral changes, showing a quadratic dependence on the field strength. Polymer films containing bacteriorhodopsin analogs show promise as new spectrally-selective photochromic and electrochromic materials.

Bacteriorhodopsins↗
PubMed1995

Holographic properties of Triton X-100-treated bacteriorhodopsin embedded in gelatin films.

Bacteriorhodopsin (b) thin films have been fabricated with varying amounts of the detergent Triton X-100 to measure the effect of this additive on the holographic performance of these thin films. Holographic spectroscopy is used to measure the effect of these detergents on the overall diffraction efficiency as well as on the phase and amplitude components of the overall signal. The diffracted rise and decay kinetics of these materials will also be presented as a function of varying detergent concentration. This research also studied the effect of this additive on the absorptive properties of bR-based thin films. Comparisons of the two complimentary sets of data are drawn.

Bacteriorhodopsins↗
PubMed1994

Retinal-protein complexes as optoelectronic components.

Naturally occurring retinal-protein complexes (RPCs) have recently received much attention with regard to their potential use as light-sensitive elements for optical recording. The best-known RPC is bacteriorhodopsin (BR), a photosensitive protein from the membrane of extreme halophilic bacteria, which has been studied in great detail. The remarkably robust nature of BR, coupled with its ability to reversibly change color upon illumination and its high cyclicity of ground-to-photoinduced state transitions, makes BR a promising material for optical information processing.

Animals↗
PubMed1987

Does bacteriorhodopsin energize the membranes of animal mitochondria under light?

A suspension of freeze-thawed mitochondria mixed with purple membranes from Halobacteria was illuminated with visible light. It was found that the light exposure prevented inhibition of succinate oxidation. The illumination also led to a decrease in inhibition of the rate of ferricyanide reduction by rat liver mitochondria in the presence of succinate. Both phenomena are explained by the fact that oxalacetate inhibition of succinate dehydrogenase is prevented by light-induced energization of mitochondrial membranes due to the contact with purple membranes.

Animals↗
PubMed1978

Spectral transitions in purple membranes from Halobacterium halobium. I. Effect of preliminary illumination on photochemical processes.

The effect of preliminary illumination of purple membranes by yellow light on the difference spectra of short-lived intermediates has been studied. It has been found that changes of the optical density of two of these intermediates, which have the maxima of the difference spectrum at 412 nm and 650 nm, coincides well with the kinetics off the known reversible transitions of the main band of the purple membrane absorption (560 570), i.e., 13-cis-trans transitions. The changes at 412 nm and 650 nm are proportional to the concentration changes of the all-trans retinal and 13-cis retinal, respectively. It was concluded that the formation of the short-lived 412 and 650 intermediates occurs in different photochemical cycles. The pH is found to affect the formation of the 650 intermediate.

Bacteriorhodopsins↗
PubMedDate not supplied

[Spectral transformations of photoproducts in Halobacterium halobium cells].

Long-living spectral products observed earlier in purple membranes (PM) are discovered in the cells of Halobacterium halobium (Hh) under the action of yellow light. Blue spectral region of the light has been found to be optimal for PM arising in the cells cultivated under light. On the basis of the changes discovered in the optical spectra of Hh we may suppose that PM arising in the cells, is the dark processes, occur due to a hypothetic enzyme, which appears under light. The rate of PM arising is maximal during the periods of thermogenesis maximum.

Bacteriorhodopsins↗
PubMedDate not supplied

[Spectral transformations in purple membranes of Halobacterium halobium: effect of 560-570 transition and blue light on photochemical processes].

Effect of reversible photodependent spectral transition 560 in equilibrium 570 of the basic absorption band in purpur membranes (PM) in water on the accumulation of short-living forms 412 and 650 of bacteriorhodopsin (BR) photochemical cycle was studied. It has been shown that photochemical transformations in BR proceed as a minimum by two independent cycles, whose initial spectral forms were represented by BR with retinene in the form 13 cis and BR with retinene in the form of trans. In the course of the transition 560-- greater than 570 a long-living spectral form 370--410--430 sensitive to the blue light is formed. On the basis of our own and literature data a new scheme of photochemical processes in PM was suggested and connection between some stages of these processes and ejection and absorption of PM protones proposed.

Bacteriorhodopsins↗