The direction of the transition moments of chlorosome pigments in ~hromatophores of the green photosynthetic bacterium Chlorobjum limicola was studied by linear dichroism. Orientation of chromatophores was achieved by stretching a polyacrylamide gel in which they were packed. It was shown that in each individual chromatophore the Q, transition moment vectors of the whole chlorosome bacterioviridin are parallel to each other and are practically ideally oriented along the chlorosome long axis. The exact value of the angle M between the bacterioviridin transition moments and the long axis of the chlorosome is calculated to be CI = O", the mean square deviation being 7". Linear dichroism Bacterioviridin orientation Green bacteria Bacterial photosynthesis ChromatophoreIt has been shown theoretically that the photosynthetic unit (PSU) structure should be strongly optimized in vivo to operate with a 90% quantum yield of primary charge separation in the reaction center (RC) El]. The basic principles of the structural organization of an optimal model's PSUs have been considered by us in [2-51. The mutual orientation of the transition moment vectors of PSU molecules is a major factor making the optimization of energy transfer from the antenna to the RC possible [4,5]. It was shown that in optimal model PSUs these vectors are parallel to each other and to either the long or short axis of an 'elementary' PSU. It is possible that in some natural PSUs the co-operative effect of several optimizing factors ensures high efficiency without requiring an 'ideal' orientational ordering of these vectors. It has been shown that, in vivo, there is at least partial orientations ordering of tr~sition dipoles [6]. We believe that if an ideal orientational ordering of transition dipoles in vivo occurs, then it would be advisable to investigate the ordering in large and efficient PSUs, for which the requirements for their structure optimization are more rigorous than those for small PSUs [I]. This is why the green sulfur bacteria were chosen for study, as their light-harvesting antenna is an order of magnitude larger than that of purple bacteria, and several-fold greater than that of higher plants. PSUs of green sulfur bacteria contain about 1000 bacte~oviridin (BVr) molecules and about 80 bacteriochlorophyll II (BChl a) molecules (per RC P840) [7,8]

The article is devoted to identifying current trends and prospects for the development of legislation of the Russian Federation on environmental emergencies in the context of changing and exponentially increasing environmental, industrial and biological threats and risks. Based on the results of the analysis of the current legislation, the conclusion is proved, according to which there is currently no appropriate regulatory and methodological framework that allows you to quickly take into account, identify and classify all possible signs and conditions for attributing certain threats and risks to an emergency of a natural, man-made, and, in particular, biological nature, in particular, in the case of epidemics. To solve the existing problems, the authors propose a number of measures to improve the current legislation on emergency situations, including by preventing (reducing the risk) of environmental disasters, emergencies, as well as eliminating their consequences by implementing a set of measures to improve the disturbed territories.

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The fluorescence kinetics of isolated Rhodospirilhun rubrum reaction centres was studied. In the picosecond time range the decay was well approximated by two exponential components. The short-lived component was observed only when P,,,, was reduced and had a maximal amplitude at about 910 nm. Its lifetime was equal to 7+2 ps both at room temperature and at 77 K. It is inferred that this fluorescence component is emitted by excited photochemically active P,,, before the formation of an intermediate radical-pair state. The second, long-lived component with a lifetime of about 100-200 ps was observed in a wider spectral range and had maxima at about 850 and 900 nm both under reducing and oxidizing conditions. The bulk of this luninescence seemed to be emitted either by photochemically inactive P,,, and/or by traces of antenna bacteriochlbrophyll. Bacterialphotosynthesis Picosecondfluorescence

The article is devoted to circular economy concept. Its three major components: material circuit, extension of resource use cycle, efficient use of renewable energy are discussed in the article. Material circuit types are also determined. Principles that determine the circuit type are distinguished. Environmental and economic impacts of circular economy are analyzed using specific examples.