Loading...
5 results
Search Results
Now showing 1 - 5 of 5
- Temperature dependence of IR exciton emission spectra in Müller cell intermediate filamentsPublication . Khmelinskii, Igor; Makarov, Vladimir I.Temperature dependences of IR exciton properties in Muller cell (MC) intermediate filaments (IFs) isolated from porcine retina were studied. It was found that the widths of the spectral emission bands in the 2500 cm-1 and 5000 cm-1 energy ranges grow with temperature. It was found that temperature effects on the bandwidth may be described by thermal activation of the low-frequency vibrational modes of the IFs. The average activation energies for the two IR bands were estimated. Considering the dynamics of IR emission, its buildup time was independent on the sample temperature, while its decay time decreased with temperature. Thus, the emission decay rate increased exponentially with the sample temperature. The mechanisms explaining the observed temperature effects were proposed and discussed. Taking into account that MC IFs are capable of transmitting ATP hydrolysis energy within and between cells, with these properties being apparently common for all IFs, these IFs may be used by cells for physical energy transport and communications. As presently reported, temperature effects upon IR exciton spectra should not affect these proposed physiological functions to any significant extent. Therefore, the currently reported data are important for improving our understanding of the physical communication mechanisms operating within and between cells.
- Intermediate filaments are natural energy conductors in live cellsPublication . Khmelinskii, Igor; Makarov, VladimirTwo possible mechanisms describing intra-and inter-cell energy transfer in biological systems were analyzed. The first one is based on Davydov vibration soliton (DVS) theory, implying C=O vibrational energy transfer along alpha-helix polypeptides. According to Davydov, a certain vibration of one of the C=O groups somehow receives the entirety of ATP hydrolysis energy within an enzyme molecule. Next, dipole-dipole interactions of the C=O groups of neighboring amino acid residues should ensure propagation of the DVS along the polypeptide chain, transporting it to the site of catalytic reaction. Strong limitations of this theory when applied to energy transfer in living systems were underlined, accompanied by total lack of experimental evidence of DVS existence. The second, much more viable mechanism, based on electronic excited state (exciton) propagation along individual protein molecules and their assemblies - intermediate filaments (IFs) - was considered and discussed in detail. Excitons in IFs may be generated by photon absorption or by ATP hydrolysis energy transfer to IFs. Infrared (IR) excitons were generated in the latter case, which propagated along IFs, enabling energy transfer within and between cells, and inter-cellular communications. Earlier is has been noted that high-contrast vision of vertebrates is based on photon energy propagation along Muller cell (MC) IFs in the form of excitons, from the inner limiting membrane retinal layer to the outer fragments of cone cells, located in the outer limiting membrane retinal layer. Therefore, MC IFs operate as photon energy guides, transferring excitons from MC to cone cells, and thus communicating external visual information to the retinal cones and the brain. We finally conclude that apparently the mechanism based on the properties of IFs as natural energy guides plays the main role in communications within and between cells of live organisms.
- IR exciton activation mechanism of ethanol oxidation by human alcohol dehydrogenase (ADH) 1A enzymePublication . Khmelinskii, Igor; Makarov, Vladimir I.Low-energy (2500 cm(-1)) exciton transfer was explored in Muller cell (MC) intermediate filaments (IFs) isolated from porcine retina and filling a capillary matrix. Excitons were generated by absorption of IR radiation at 4 mu m. The effects of these excitons on ethanol oxidation by human alcohol dehydrogenase (ADH1A) enzyme were quantified. It was found that IR excitons transferred to the enzyme accelerated alcohol oxidation rate, which increased by the factor of 2.76 when exciting the IFs with 2.39 mu W/cm(2) of 4 mu m IR light. Power dependence of the oxidation rate was also explored. These results show that IFs may be transmitting energy to enzyme mole-cules in vivo, facilitating enzymatic reactions. The required excitons may be produced by cells at the cost of adenosine triphosphate (ATP) hydrolysis energy. Therefore, such control mechanism for enzymatic reactions may be operational in living systems. Direct activation of the enzyme by IR radiation with 4 mu m wavelength did not occur; instead, indirect activation of the IF...ADH1A...NAD (nicotinamide adenine dinucleotide)...EtOH complex occurred by energy transfer of the IR exciton to the ADH1A molecule of this complex. Considering that every living cell has a network of IFs, a similar reaction control mechanism may be operational in vivo, providing a much faster energy supply redirection within the cell than ATP diffusion, and justifying a closer inquiry.
- Energy transfer along Müller cell intermediate filaments isolated from porcine retina: II. Excitons at 2500 cm−1 produced by ADH1A upon hydrolysis of one ATP moleculePublication . Khmelinskii, Igor; Makarov, Vladimir I.Low-energy (IR -2500 cm-1) exciton transfer was explored in Muller cell (MC) intermediate filaments (IFs) isolated from porcine retina and filling a capillary matrix. IR excitons were generated either by absorption of IR radiation at 4 mu m, or by ATP hydrolysis energy transfer to the MC IFs. ATP hydrolysis was catalyzed by human alcohol dehydrogenase (ADH1A) in ADH1A...NAD+...IF complexes. Each exciton was generated by hydrolysis of one ATP molecule. Exciton energy was independent on ATP concentration. The emission spectra of IR excitons arriving to the other side of the capillary matrix were dependent on the exciton generation method. Timeresolved experiments with direct exciton generation by pulsed IR radiation allowed to measure exciton travel velocity, along with the exciton emission time. The results obtained support new ideas on ATP energy transfer along protein filaments in vivo. These unique experimental results provide for detailed understanding of the electronic state structure of the MC IFs. This study reports that MC IFs isolated from porcine retina have a longliving low-lying electronic excited state at 2500 cm-1 above the ground state.
- Effects of pulsed electric fields on exciton propagation efficiency along Müller cell intermediate filaments. Possible separation mechanism of high- and low-contrast images by the eye-brain systemPublication . Khmelinskii, Igor; Makarov, Vladimir I.In the current study, we tested a possible mechanism of low-and high-contrast image component discrimination by the vertebrate eye-brain system. Apparently the eye-brain system has to discriminate between the low-contrast image component formed by light scattered within the retina, due to interaction of photons with cells and their parts, and the high-contrast image component transmitted by excitons via the quantum mechanism. Presently, effects of pulsed electric fields applied to Muller cell (MC) intermediate filaments (IFs) on the efficiency of exciton propagation were explored. The effects of both pulse duration and amplitude were recorded. These experimental results show that the eye-brain system may be using signal modulation to discriminate between high-and low-contrast image components, improving our understanding of high-contrast vision in vertebrates.