[The Use of the abundance ratio of 13C and 12C isotopes for characteristic of the origin of ethyl alcohol]. / Ispol'zovanie otnoshenii rasprostrannennostei izotopov 13C i 12C dlia kharakteristiki proiskhozhdeniia étilovogo spirta.

During alcohol fermentation, the carbon isotope composition of ethyl alcohol produced depended on the substrate used and was characterized by the value of delta 13C equal to -24.7 +/- 0.8/1000 (wheat grain), -22 +/- 0.1/1000 (rye grain), -22 +/- 0.5/1000 (products of wood hydrolysis), -15.3 +/- 0.3/1000 (maize grain) and -10 +/- 0.1/1000 (sugar cane). The isotope composition of carbon of ethyl alcohol obtained during catalytic hydroxylation of ethylene has a delta 13C of -30.6 +/- 0.3/1000. The possibility of quantitative determination of specific components in mixtures of ethanol samples with various isotope compositions (chemical synthesis and alcohol fermentation of raw material from C3- or C4-plants) was shown.

[Effect of a magnetic field on the fluorescence yield of Rhodopseudomonas sphaeroides cells of the wild strain and strain R-26. Relationship to temperature]. / Vliianie magnitnogo polia na vykhod fluorestsentsii kletok Rhodopseudomonas sphaeroides dikii shtamm i R-26. Temperaturnaia zavisimost'.

Fluorescence yield of Rhodopseudomonas sphaeroides cells whose primary acceptor is chemically reduced depends on the magnetic field tension. The maximal value of relative magnetic effect and the field value, at which the effect amounts to a half of the maximal value for R. sphaeroides wild strain and R-26, equal 3.6 and 1.1%; 260 and 120 G correspondingly at 295 K. An effect of th magnetic field on fluorescence yield for R. sphaeroides wild strain at the medium potential 300 mV was observed. The values of relative magnetic effect were shown to change within the temperature range 295-120 K. The results obtained are discussed in terms of the relationship between these parameters and the velocity constant values of the radical paris recombination (P 870(+) . Bph(-) . in singlet and triplet states and the value of metabolic interaction in the radical pairs (P 870(+) . Bph(-) .) and (Bph(-) . --X(-) .).

[EPR study of redox titration of Chromatium minutissimum chromatophores]. / Izuchenie metodom EPR okislitel'no-vosstanovitel'nogo titrovaniia khromatoforov Chromatium minutissimum.

Redox titration of chromatophores through the region +300 +570 mV at room temperature results in generation of two dark ESR signals, a well-known reaction center signal and a new narrow line. This line is characterized by deltaH pp = 4.2 Oe, g-factor about that of RC and a Lorentzian shape. It is insensitive to illumination. The determination of an RC signal midpoint potential is affected by the presence of the narrow line. Taking into account the superposition of the two ESR signals it was measured to be +(486+/-+/-18)mV.

[Comparative study of the photopotential and EPR signal arising after photooxidation of metal substituted pheophytins]. / Sravnitel'noe izuchenie fotopotentsiala i signala EPR, voznikaiushchikh pri fotookislenii metallzameshchennykh feotitinov.

Ethanolic solutions of Zn-, Cd-Phe a and b and Chl a and b with p-benzoquinone as electron acceptor have been studied at pH 4. In all systems positive photopotentials and singlet ESR lines of the pigment cation radicals are observed. A conclusion is made that the photopotential is only partly attributable to an electrode reaction of the cation radicals, to a greater extent arising due to unknown, non-radical particles.

[Mechanism of photochemical oxidation of bacterioviridin]. / Issledovanie mekhanizma fotokhimicheskogo okisleniia bakterioviridina

The mechanism of bacterioviridin photochemical oxidation has been studied by the methods of ESR, flash-photolysis and low-temperature spectrophotometry. ESR spectrum of pigment cation-radical, a singlet line with H=11 G, g = 2.0027, has been recorded. The bands with maxima at 370, 470, 525, 590, 840 nm correspond to bacterioviridin cation -- radical in the absorption spectra. When -- benzoquinone is used as an electron acceptor with excitation light 640 nm the product of bacterioviridin irreversible oxidation is formed with the absorption band maximum 760 nm and absorption between 350 and 370 nm. It is suggested that this product is of double-oxidized non-radical nature and the mechanism of its formation through oxidation of the pigment cation-radical is discussed. The regeneration reaction of double-oxidized bacterioviridin up to cation-radical form in the presence of triphenylamine as a reducing agent has been carried out. The rate constants of cation-radical decay in the dark and desactivation of triplet state have the following values: K1=(1,64+/-0,15)-10(3) sec-1, K2=(13+/-2,0)-10(3) sec-1 correspondingly. The activation energy of the radical decay in the dark is Eact =(13,2-0,5) kcal/mole.

[EPR study of the mechanism of photooxidation of chlorophyll a by nitro compounds]. / Issledovanie metodom EPR mekhanizma fotookisleniia khlorofilla a nitrosoedineniiami

An ESR signal with g-value of 2,0026 and peak-to-peak with 8,5 Oe was observed in ethanole solutions of chlorophill a and nitroderivatives of naphtalene under red light illumination. The ESR signal consisted of chlorophyll cation radical resonance, superimposed on an nitronaphtalene anion radical. Less than the ratio greater than between the quantities of these radicals and the character of decay kinetics are influenced by the medium acidity. An analysis of kinetic curves is performed, and the effect of the medium acidity on the mechanism of one-electron transfer reaction between chlorophyll and nitronaphtalene molecules is explained.

[Photochemical generation of the cation-radical of bacteriochlorophyll b and the anion-radical of bacteriochlorophyll b and bacteriopheophytin b, components of the photosynthesizing bacteria Rhodopseudomonas viridis]. / Fotokhimicheskaia generatsiia kation-radikala bakteriohkhlorofilla b fotosinteziruiushchikh bakteriaakh Rhodopseudomonas viridis

The mechanism of photochemical redox reaction of bacteriochlorophyll b, bacteriopheophitin b was studied. The oxidation of bacteriochlorophyll b was carried out in ethanole by means of p-benzoquinone. In ESR spectra the singlet line with delta H = 8.4 gs and g = 2.0025 corresponded to cation-radical. The changes within the region of 400-500 nm, 500-600 nm and the band with the maximum at 685 nm corresponded to cation-radical in the absorption spectra. Photoreduction of bacteriochlorophyll b and bacteriopheophitin b was carried out in triet containing phenilhydrosin. Anion-radicals of bacteriochlorophyll b and bacteriopheophitin b observed in the ESR spectra had singlet form with weak and superthin structure and correspondently with delta H = 10 gs, delta H = 12 gs. The spectrophotometric characteristics of the above pigments were obtained.