Visualization and Cytotoxicity of Fluorescence-Labeled Dimeric Magnetite-Gold Nanoparticles Conjugated with Prostate-Specific Membrane Antigen in Mouse Macrophages.

We demonstrated the possibility of penetration of magnetite-gold nanoparticles conjugated with prostate-specific membrane antigen into mouse macrophages. It was found that after 3-h incubation with nanoparticles in a concentration of 15 mg/liter at 37oC, they were seen in only 13% macrophages. In about 90% cells, the nanoparticles were detected within the cytoplasm. Under these conditions, membrane damage was revealed in 25% cells. These results should be taken into account in further development and application of nanomaterials for diagnostic and therapeutic purposes in oncology.

[Effect of the incubation medium pH on damage to macrophages plasma membranes].

In this paper we showed the pH-dependent change in the sensitivity of the membranes of murine peritoneal macrophages to UV-radiation. This relationship is discussed in terms of lipid bilayer membrane stability modification to the action of ROS and lipid peroxidation process (LPP) at different pH. Iron-ascorbate reinforced LPP also led to pH-dependent membranes damage. The increase of the cells incubation medium temperature up to 37 degrees C, which also stimulated LPP, did not change the picture of the pH-dependent damage. Decrease of the incubation medium pH did not reduce H2O2-induced cell damage. Increase of the pH intensified the cells damage.

[Damaging effect of digitonin on macrophage plasma membranes exposed to UV-irradiation].

It was shown that macrophage irradiation in 4.6 J/cm2 (lambda(max) = 306 nm) dose leads to small quantity of damaged cells in cell population, which doesn't change substantially during 60 min of incubation in darkness. So as detergent digitonin treatment (without irradiation) in 3 mkg/ml concentration doesn't lead to substantial cell damage. Also the result of combined influence of UV-irradiation and digitonin added after irradiation, 15 min before the damaged cells counting, has been got. It was shown that macrophage incubation for 15 minutes leads to cell damaging twice as much sum of UV (4.6 J/cm2) and digitonin (3 mkg/ml) damaging. However the level of cell damaging obtained 30 minutes later after finishing of irradiation doesn't exceed the sum of separate effects of this factors. Further increase of postradiation time leads to synergic effect again.

Phototransformation and proton pumping activity of the 14-fluoro bacteriorhodopsin derivatives.

The photoinduced behavior and proton pumping characteristics of some bacteriorhodopsin (BR) analogs with fluorinated chromophores (all-trans 14-fluorinated [14-F] retinal and 13-cis 14-F retinal) derived from wild type (WT) and D96N mutant BR were investigated. These analogs were characterized using spectrophotometry and a highly sensitive electrochemical technique. Similar to the white membrane JW2N, the apomembranes WT ET 1000 and D96N form photoactive pigments with the 14-F chromophores. The resulting analogs have a major absorption band at 588 nm. Red-shifted pigment (lambdamax500 nm) only in the 14-F analogs derived from WT ET 1000. The measurements of the photoinduced transformation in 14-F WT analogs show that the photocycle of the major pigment occurs simultaneously with the process in the red region and is partially masked by the formation of the red-shifted species. The 14-F D96N samples have a significantly slower and more complicated photoinduced behavior. Electrochemical measurements show that the photoinduced transformation of the red species is not accompanied by proton transport.

The cycle of photochromic reactions of a bacteriorhodopsin analog with 4-keto-retinal.

Photochemical reactions in a bacteriorhodopsin analog with 4-keto-retinal (4-keto-BR) were studied by using low-temperature and pulsed laser absorption spectroscopy. A photocycle of the photochemical reactions of 4-keto-BR is proposed, which, unlike the photocycle of native BR, includes several spectrally and kinetically distinguishable M-type and O-type intermediates.

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.

Photoinduced transformation of 14-F-bacteriorhodopsin gelatin films based on both wild type and D96N mutant.

Spectral and kinetic transformations were studied in gelatin films made with 14-F wild type (WT) bacteriorhodopsin (BR) and 14-F D96N mutant BR. Unlike the recent study of water suspensions of the same pigments, where a red shifted species at 660 nm was shown to form under the light in 14-F WT only, there are no drastic differences in photoinduced behavior between gelatin films based on 14-F WT and 14-F D96N. It is not observed any photoinduced formation of red shifted species at 660 nm for both types of films as it is observed for corresponding pigments in water suspension. The observed results are explained in a terms of relationship between the rates of two photoinduced processes that occur in suspensions and films of corresponding pigments. Kinetic characteristics of the photoinduced processes for the films with chemical additives suggest that there are no advantages in using 14-F D96N films when compared to films based on 14-F WT.

[Alteration of intracellular pH of macrophages after UV-irradiation]. / Izmenenie vnutrikletochnogo pH makrofagov posle UF-oblucheniia.

It was shown that in vitro exposuse of mice peritoneal middle-wave ultraviolet radiation (lambdamax = 306 nm) in doses which don't damage to cause plasma membrane caused dose-dependent decreasing of their intracellular pH. After exposure of cells to 0.5 J/cm2 it was detected an acidification of intracellular contents followed by an increase of intracellular pH up to control level (after 40 min of incubation) and then above it (on 45 min of incubation). An increase of irradiation dose was accompanied by more evident reduction of intracellular pH and lack of its restoration on 45 min of postradiational incubation under irradiation with a dose of 3 J/cm2.

Mechanism of nonlinear photoinduced anisotropy in bacteriorhodopsin and its derivatives.

Polymer films made with photosensitive chromophore protein bacteriorhodopsin (BR) from the extreme halophile Halobacterium salinarium as well as films made with BR derivatives exhibit a nonlinear photoinduced anisotropy. Two different methods can be used to induce anisotropy in polymer BR films. The first method is based on the anisotropic properties of the initial form of the photocycle, BR570 (B-type anisotropy). Another method is based on the anisotropic properties of the longest-lived photocycle intermediate M412 (M-type anisotropy). CW gas lasers were employed to induce a reversible anisotropy in polymer BR films. Nonlinear photoinduced anisotropy is discussed in the context of a model for the anisotropic photoselection of BR molecules under linearly polarized light. A comparison of the experimental dependencies of nonlinear photoinduced anisotropy on laser intensity with similar calculated dependencies enables one to determine the molecular dichroism of BR and its derivatives not only for the initial form of the photocycle, B but also for the longest-lived intermediate M. Here we present the data showing the correlation between the laser induced nonlinear anisotropic properties and chromophore/protein interactions in BR. The effect of polymer binder on the nonlinear photoanisotropic properties of polymer BR films is also described.