[Accumulation of α-tocopherol and ß-carotene in Euglena gracilis Cells under Autotrophic and Mixotrophic Culture Conditions].

The aim of the work was to find the mode of cultivation of unicellular flagellate Euglena gracilis, favorable for the simultaneous accumulation of α-tocopherol and ß-carotene. Cells were grown either in photoautotrophic or photoheterotrophic conditions in the presence of 100 mM ethanol (variant Et) or 40 mM glutamate (variant Gt), or their combination (variant EtGt). The exogenous substrates significantly stimulated light-dependent growth of E. gracilis. The largest increase of biomass was recorded on the 20th day in the variant EtGt and exceeded the autotrophic control by 7 times. The content of ß-carotene and chlorophyll (Chl) per cell in mixotrophic cultures exceeded the control by 2-3 and 1.6-2 times, respectively. At the same time, α-tocopherol accumulation in autotrophic cells was greater than in the cells of mixotrophic cultures by 2-7 times. Total yield of tocopherol per unit volume of culture medium, which depended not only on its intracellular content, but also on the amount of accumulated biomass was highest in EtGt variant. A correlation between the accumulation of the antioxidants and the equilibrium concentration of oxygen in the growth medium, which depended on the intensities of photosynthesis and respiration has been analyzed.

[THE EFFECT OF ACID RAIN ON ULTRASTRUCTURE AND FUNCTIONAL PARAMETERS OF PHOTOSYNTHETIC APPARATUS OF PEA LEAVES].

The effects of simulated acid rain (SAR) on the ultrastructure and functional parameters of the photosynthetic apparatus were studied using 14-day-old pea leaves as test system. Pea plants were sprayed with an aqueous solution containing NaNO3(0.2 mM) and Na2SO4(0.2 mM) (pH 5.6, a control variant), or with the same solution, which was acidified to pH 2.5 (acid variant). Functional characteristics were determined by chlorophyll fluorescence analysis. Acid rain application caused reduction in the efficiency of the photosynthetic electron transport by 25%, which was accompanied by an increase by 85% in the quantum yield of thermal dissipation of excess light quanta. Ultrastructural changes in chloroplast were registered by transmission electron microscopy (TEM) after two days of the SAR-treatment of pea leaves. In this case, the changes in the structure of grana, heterogeneity of thylakoids packaging in granum, namely, the increase of intra-thylakoid gaps and thickness of granal thylakoids compared to the control were found. The migration of protein complexes in thylakoid membranes of chloroplasts isolated from leaves treated with SAR was suppressed. It was shown also that carbonic anhydrase activity was inhibited in chloroplast preparations isolated from SAR-treated pea leaves. We proposed a hypothesis on the possible inactivation of thylakoid carbonic anhydrase under SAR and its involvement in the inhibition of photochemical activity of chloroplasts. The data obtained allows to suggest that acid rains negatively affect the photosynthetic apparatus disrupting the membrane system of chloroplast.

Spectroscopic and photophysical properties of protonated forms of some fluoroquinolones in solutions.

Electronic absorption and fluorescence spectra of ciprofloxacin, norfloxacin, enoxacin, pefloxacin and nalidixic acid in aqueous solutions were investigated. The time-resolved fluorescence spectra were measured and interpreted. The changes of the luminescence spectra and electron structure of the compounds under study are explained by different degrees of the spin-orbital interaction caused by nitrogen heteroatoms lone pairs effect. Possible ways of the protonation process for naphtyridine and quinolone rings with different substitutions are discussed. The photophysical behavior of FQs was studied using density functional theory (DFT) calculations.

Bis(dihydrogen norfloxacinium) tri-µ(2)-chlorido-bis-[trichloridobismuthate(III)] chloride dihydrate.

The title compound, {systematic name: (3-carb-oxy-1-ethyl-6-fluoro-7-piperazin-4-ium-1-yl-1H-quinolin-4-yl-idene)oxonium tri-µ(2)-chlorido-bis-[trichloridobismuthate(III)] chloride dihydrate], (C(16)H(20)FN(3)O(3))(2)[Bi(2)Cl(9)]Cl·2H(2)O, is composed of [Bi(2)Cl(9)](3-) anions lying on crystallographic twofold rotation axes, Cl(-) anions also on twofold axes, C(16)H(20)FN(3)O(3) (2+) cations, and water mol-ecules. The Bi(III) coordination polyhedron is a distorted octa-hedron and two such octa-hedra share a triangular face to form the complex anion. There are three short terminal Bi-Cl bonds [2.5471 (6)-2.5781(5 Å] and three longer bridging bonds [2.8599 (5)-2.9984 (6) Å] in each octa-hedron. Anions, cations and water mol-ecules are linked by hydrogen bonds to form a three-dimensional network. There are also π-π stacking inter-actions between quinoline ring systems, with an inter-planar distance of 3.27 (1) Å.

Tetra-kis(dihydrogen pefloxacinium) di-µ(2)-chlorido-bis-[tetra-chloridobismuthate(III)] tetra-chloride octa-hydrate.

The title compound {systematic name: tetra-kis[4-(3-carb-oxy-1-ethyl-6-fluoro-4-hydroxonio-1,4-dihydro-7-quinol-yl)-1-meth-yl-piperazin-1-ium] di-µ(2)-chlorido-bis-[tetra-chlorido-bismuth-ate(III)] tetra-chloride octa-hydrate}, (C(17)H(22)FN(3)O(3))(4)[Bi(2)Cl(10)]Cl(4)·8H(2)O, is composed of edge-shared centrosymmetric dinuclear [Bi(2)Cl(10)](4-) anions, Cl(-) anions, dihydrogen pefloxacinium cations and water mol-ecules. The Bi(III) coordination polyhedron is a distorted octa-hedron. There are four short terminal Bi-Cl bonds [2.5037 (10)-2.6911 (7) Å] and two longer bridging bonds [2.8834 (8) and 3.0687 (9) Å] in each octa-hedron. Two sets of chloride ions and water mol-ecules are disordered over the same sites with site occupancies of 1/3 and 2/3, respectively. Anions, cations and water mol-ecules are linked by O-H⋯O, O-H⋯Cl and N-H⋯Cl hydrogen bonds, forming a three-dimensional framework. There are also π-π stacking inter-actions between quinoline ring systems [centroid-centroid distance = 3.575 (1) Å].

[Effect of copper ions on the light-induced proton transfer in spinach chloroplasts].

It was shown that the light-dependent proton uptake by a suspension of isolated chloroplasts was completely inhibited in the presence of 30-50 microM Cu2+ ions at the 0.1-0.3 Cu2+/Chl ratio. At the same time, the rate of photosynthetic oxygen evolution in the presence of 30-200 microM CuSO4 was reduced by no more than 20-30% of control and up to 50% of the control DeltapH value was retained. The results allow us to suppose that, in the presence of copper ions: 1) electron transport in PS2 is inhibited at the level of the secondary quinone acceptor Q(B) whose photoreduction is accompanied by proton uptake from external medium; and 2) an alternative pathway of electron transfer to terminal acceptor is activated, which provides the photooxidation of water and the formation of transmembrane proton gradient.