[Comigration of root nodule bacteria and bean plants to new habitats: coevolution mechanisms and practical importance (review)].

The review summarizes the results of studies on the comigration of tubercular bacteria and bean plants to new habitats, which is often accompanied by a decrease in the symbiosis efficiency due to a loss of the diversity of genes responsible for the interaction. This migration may lead to a rise in new symbionts as a result of gene transfers from initial symbionts to local bacteria. It was demonstrated that typically new symbionts lack an ability for N2 fixation but are highly competitive, blocking the inoculation of bean cultures by industrial strains. The design of coadapted systems of recognition and signal interaction of partners is a perspective approach to ensure competitive advantages of efficient rhizobia strains introduced into agrocenoses, together with host plants, over inactive local strains.

[On structure and function of "chlorosoma" of green bacteria].

An assertion is substantiated that what is widely termed as chlorosoma of green bacteria--is not a bioparticle, but simply microscopic bacteriochlorophyll-c crystals. Apparently the creation of "chlorosoma" represents the first mostly unsuccessful evolutionary attempt to produce the regulatory mechanism in photosynthesis, which should react to the variations in the intensity of solar light reaching earth surface. It could not be successful without bacteriochlorophyll cooperation with proteins.

[On the efficiency of energy migration from chlorosoma to the main bacteriochlorophyll in green bacteria].

It is shown that the results provided in a variety of publications, which deal with structural characterization of green bacteria chlorosoma, are in explicit contradiction with kinetic and energy characteristics of microorganisms studied. The data on chlorosoma structure and composition represent no explanation as to how the additional quantity of electronic excitations generated by light in its dominating pigment C750 feeds the main photosystem.. In order to reveal the contradictions, the structural and spectral data on chlorosoma are analyzed in cooperation with the theory of inductive resonance developed by T. Ferster.

[To the question of the status and the application area of the Ferster' theory to energy migration in photosynthesis].

The main motive which stimulated author in writing this paper was a series of remarks by the reviewers of his articles. Some reviewers stated that Ferster' theory can not represent excitation migration in cases when electronic excitations are delocalized in several molecules. Two of reviewers even directly have proclaimed about "out of date Ferster' theory". This question is evidently of general importance. Therefore this paper contains the detailed analysis of the types of molecular ensembles and conditions which enable one to use correctly the Ferster' theory of inductive resonance.

[Molecular genetic mechanisms used by legumes to control early stages of mutually beneficial (mutualistic) symbiosis].

Recent data on the plant control of early stages of mutually beneficial (mutualistic) symbioses of legumes, the mechanisms of perception and transmission of the microsymbiont's molecular signals in the macrosymbiont's cells, and induction of the genetic programs of the development of symbiotic compartments and organs of the plant are summarized. It is demonstrated that the genetic system of the plant controlling the development of nitrogen-fixing symbiosis of legumes (symbiotic root nodules), which emerged 70-80 Ma ago, has undoubtedly evolved on the basis of the genetic system controlling the development of the symbiosis with arbuscular mycorrhizal fungi (which emerged 40-500 Ma ago. Interactions between genes and between gene products, as well as exchange of molecular signals, form the basis of mutually beneficial (mutualistic) plant-bacterium interactions. Even in the case of a highly specific nitrogen-fixing symbiosis of legumes (symbiotic nodules), the receptors perceiving the signal from root-nodule bacteria may function in different ways. The development of arbuscular mycorrhiza and nitrogen-fixing symbiosis in legumes is a multistep process involving hundreds of genes of both the macro- and microsymbionts. For the symbioses to develop successfully, these genes should act in a coordinated way in the newly formed superorganismal system. Further studies are necessary to shed light onto the complexity of the plant genetic control of the development of mutualistic symbioses in legumes and provide information required for improving their functions in adaptive plant-breeding systems.

[Distribution of legume arabinogalactanprotein-extensin (AGPE) glycoproteins in symbiotically defective pea mutants with abnormal infection threads].

The interface between the host cell and the microsymbiont is an important zone for development and differentiation during successive stages of the rhizobium-legume symbiosis. Legume root nodule extensins, otherwise known as arabinogalactanprotein-extensin (AGPE) are abundant components of the infection thread matrix. We have characterized the origin and distribution of these glycoproteins at the symbiotic interface of root nodules of symbiotically defective mutants of pea (Pisum sativum L.) using immunogold localization with MAC265 an anti-AGPE monoclonal antibody. For mutants with defective growth of infection threads, the AGPE epitope was abundant in the extracellular matrix surrounding infected host cells in the central infected tissue of the nodule as well as being present in the lumen of Rhizobium-induced infection threads. This suggests a mis-targetting of AGPE as a consequence of abnormal growth of the infection threads. Furthermore, mutants in gene sym33 showed reduced labelling with MAC265, and in infection threads and droplets label was completely absent, a phenomenon not observed in wild-type nodules. This suggests an alteration in the composition of the infection thread matrix for sym33 mutants which may be correlated with the absence of endocytosis of rhizobia into the host cytoplasm.

[Are "giant" chlorosomes part of light-harvesting antennae of the photosynthetic apparatus in green bacteria?].

Some data on the structure and composition of chlorosomes are in contradiction with their energy and kinetic characteristics. Among them is the enormously short excitation lifetime of the dominating chlorosoma pigment C740 in three-dimensional giant chlorosoma (with about 1000 pigment molecules per reaction center). With these times, it is hardly possible to obtain an efficient excitation transfer from this pigment to the bacteriochlorophyll B795 of the base plate and further to the main bacteriochlorophyll B860, which directly serves as reaction centers. This result was obtained by modeling the energy migration between these pigment fractions in maximally optimized conditions. Possible reasons and mechanisms responsible for such a strong nonphotochemical quenching of electronic excitations in the pigments of giant chlorosomes are substantiated and discussed.

[Comparative genome analysis in pea Pisum sativum L. varieties and lines with chromosomal and molecular markers].

C banding, Ag-NOR staining, FISH with pTa71 (45S rDNA) and pTa794 (5S rDNA), and RAPD-PCR analysis were used to study the genome and chromosome polymorphism in four varieties (Frisson, Sparkle, Rondo, and Finale) and two genetic lines (Sprint-2 and SGE) of pea Pisum sativum L. A comparison of the C-banding patterns did not reveal any polymorphism within the varieties. The most significant between-variety differences were observed for the size of C bands on satellite chromosomes 4 and 7. All grain pea varieties (Frisson, Sparkle, and Rondo) had a large C band in the satellite of chromosome 4 and a medium C band in the region adjacent to the satellite thread on chromosome 7. C bands were almost of the same size in the genetic lines and vegetable variety Finale. In all accessions, 45S rDNA mapped to the secondary constriction regions of chromosomes 1, 3, and 5. The signal from chromosome 5 in the lines was more intense than in the varieties. Ag-NOR staining showed that the transcriptional activity of the 45S rRNA genes on chromosome 7 was higher than on chromosome 4 in all accessions. No more than four Ag-NOR-positive nucleoli were observed in interphase nuclei. Statistical analysis of the total area of Ag-NOR-stained nucleoli did not detect any significant difference between the accessions examined. RAPD-PCR analysis revealed high between-variety and low within-variety genomic polymorphism. Chromosomal and molecular markers proved to be promising for genome identification in pea varieties and lines.

[A new methodical approach to the determination of the quantum yield of the photoelectric conversion of electronic excitations in reaction centers of purple bacteria].

A new methodical approach has been developed, which enables one to determine with a high precision (approximately 1.5%) the quantum yield of energy conversion in reaction centers isolated from purple bacterium. This parameter for reaction centers from Rhodospirillum rubrum was estimated to be 93.5 +/- 1,5%. Our methodical approach makes it possible to calculate quantum yield values for complete photosystems of purple bacteria.

[Regulatory genes of garden pea (Pisum sativum L.) controlling the development of nitrogen-fixing nodules and arbuscular mycorrhiza: a review of basic and applied aspects].

The review sums up the long experience of the authors and other researchers in studying the genetic system of garden pea (Pisum sativum L.), which controls sthe development of nitrogen-fixing symbiosis and arbuscular mycorrhiza. A justified phenotypic classification of pea mutants is presented. Progress in identifying and cloning symbiotic genes is adequately reflected. The feasibility of using double inoculation as a means of increasing the plant productivity is demonstrated, in which the potential of a tripartite symbiotic system (pea plants-root nodule bacteria-arbuscular mycorrhiza) is mobilized.

[Photosynthesis as a prototype of solar energetics of new type. I. Chlorophyll apparatus of photosynthesis]. / Fotosintez kak proobraz solnechnoi énergetiki novogo tipa. I. Khlorofil'nyi apparat fotosinteza.

The hybridization of double-stranded regions of pre-mRNA from mouse Ehrlich ascites carcinoma cells, rabbit bone marrow cells and primary culture of rabbit kidney cells with an excess of total poly(A)+-mRNA of mouse or rabbit globin mRNA respectively was studied. The hybrids were detected as RNAase-stable acid precipitable material or by adsorbtion of the hybrid complexes of poly(U)-sepharose. The sizes of the hybrid complementary sequences and their thermal stability were estimated.

[Model of water participation in stabilization of charges in primary photosynthesis events]. / Rolvody v stabilizatsii rasdelennykh zariadov v pervichnom akte fotosinteza.

A hypothesis is elaborated which advances a model of primary change separation in photosynthetic reaction centres. This model implicates two principal ideas: i) photoexcitation (or excitation migration from antenna chlorophyll) of reaction centre dimer (P700, P840, P870-P890) induces a charge transfer state with an electron from one molecule being transferred to another one (corresponding distance must be approximately greater than 6 A); ii) the above state is stabilized due to rapid (congruent to l psec) orientation of electric dipoles of nearest water molecules in the local field of dimmer transition moment. The quantitative energetic calculations confirm the consistence of the hypothesis with the literature data available and enables us to explain the molecular mechanisms of some primary events of photosynthesis.

[Delayed bacteriochlorophyll luminescence and the primary stages of electron transport in photosynthetic reaction centers of purple bacteria]. / Zamedlennaia liuminestsentsiia bakteriokhlorofilla i pervichnye stadii perenosa élektrona v reaktsionnykh tsentrakh fotosinteza purpurnykh bakterii.

The results of studies of charge separation in photosynthetic reaction centers of purple bacteria are summarized. The findings concerning the sequence of initial steps of the electron transfer and properties of the electron carriers obtained by direct methods of differential optical absorption and ESR spectroscopy are compared with the data on the bacteriochlorophyll delayed fluorescence resulting from reversal of charge separation. The data analysis gives an integrated description of the reaction center operation which is not avoid of discrepancies.

[Factors of the optimization of the light-harvesting antenna structure of the photosynthetic unit]. / Faktory optimizatsii struktury svetosobiraiushchei antenny fotosinteticheskoi edinitsy.

The principles of model construction of pigment apparatus affecting the rate of energy trapping are analysed. The basic properties of the model system allowing optimization of this process are as follows: the spectral heterogeneity of light-harvesting pigment antenna; the proper mutual orientation of transition moment vectors of antenna molecules; the space arrangement of light-harvesting antenna molecules; the availability of "the focusing zone" of reaction centers, which is formed by the nearest to reaction centers antenna molecules.

[Intermediate states formed during discharge separation in the reaction centers of Rhodospirillum rubrum in the presence of a low-redox potential]. / Promezhutochnye sostoianiia, obrazuiushchiesia pri razdelenii zariadov v reaktsionnykh tsentrakh Rhodospirillum rubrum v usloviiakh nizkogo okislitel'nogo-vosstanovitel'nogo potentsiala.

The intermediate short-lived states arising in reaction centre preparations (RC) of purple bacterium Rhodospirillum rubrum are investigated under the conditions of low redox potential. Excitation by 353 and 530 nm laser pulses produced two states characterized by optical absorption changes in the range of 350--650 nm and lifetimes: 10--30 ns for the first state and 2.5 +/- 0.5 microseconds for the second one. The first state is similar to the state PF, described previously by Parson et al. for RC from Rps. sphaeroides. Carotenoid extraction with isooctane resulted in changing the spectrum with tau = 2.5 microseconds and in the appearance of new absorption changes similar to those for the R state observed before in carotenoidless bacterial strains within microsecond time range. The comparison of the microsecond spectra with difference spectra (continuous light minus dark) of RC from R. rubrum in the range of 350--650 nm made it possible to identify the states with tau = 2.5 microseconds as carotenoid triplet states. The ratio of quantum yields of PR and carotenoid triplet states production was determined as being 1 : 1. The conclusion was made that triplet-triplet energy transfer from state PR to carotenoid is responsible for the production of carotenoid triplet states.

[Means of optimizing light energy conversion in the primary stages of photosynthesis. II. Optimization of the structure of an uniform photosynthetic unit lattice]. / Puti optimizatsii preobrazovaniia svetovoi énergii v pervichnykh aktakh fotosinteza. II. Optimizatsiia stroeniia reshetki odnorodnoi fotosinteticheskoi edinitsy.

The possibility of optimization of the structure of a model photosynthetic unit lattice is analysed. The efficiency of the photosynthetic unit operation is evaluated from the time of excitation energy trapping by reaction centers. The calculations assume a Förster inductive resonance mechanism for energy transfer within light--harvesting antenna and pairwise dipolar interactions. We use the probability matrix method which is adapted to excitation trapping time (but not to excitation jumps number) calculation. It is shown that the specific anisotropy of the distances between antenna molecules (which is in principle possible due to the diskshaped form of chlorophyll molecules) in combination with the optimal spatial arrangement of reaction centers as "well regulated clusters" allows to decrease the time of excitation energy trapping by over an order of magnitude. The requirements for optimization of the structure of a macroscopic photosynthetic unit lattice and the consequences following from them for the in vivo systems are formulated.

[Effect of dehydration on the primary picosecond stages of charge separation in Rhodospirillum rubrum]. / Vliianie obezvozhivaniia na pervuchnye pikosekundnye stadii razdeleniia zariadov u Rhodospirillum rubrum.

Effects of dehydration on the quantum yield of charge separation in the reaction centres, fluorescence and nanosecond recombination luminescence in R. rubrum chromatophores have been investigated. It has been shown that dehydration results in more than a 10 times decrease in the quantum efficiency of photosynthesis. Besides, photoinduced fluorescence changes practically disappear in dehydrated samples and the parameters of nanosecond luminescence substantially change. These observations indicate that strong dehydration causes a deterioration of the primary charge separation process at the early picosecond stages of excitation energy transduction into energy of separated charges. This is, probably, due to either changes in the dynamic characteristics of the reaction centre pigment-protein complex or alteration in the structure state (spacings and mutual orientations) of the primary reactants involved in the primary charge separation.

[Kinetics and spectra of photo-induced changes in the absorption of pigment-protein complexes of photosystem 1 in a picosecond range]. / Kinetiki i spektry fotoindutsirovannykh izmenenii pogloshcheniia u pigment-belkovykh kompleksov fotosistemy 1 v pikosekundnom diapazone.

The energy transfer from the light-harvesting antenna chlorophylls to the reaction center molecules and subsequent charge separation were investigated using a difference picosecond spectrophotometer with selective excitation. The objects were the pigment-protein complexes of photosystem 1 (Chl/P700 = 60) isolated from bean leaves. The difference absorption spectra of the excited states of light-harvesting antenna chlorophylls and the P700 photooxidation were measured. It was shown that the excited states of antenna chlorophylls were generated within 10 ps and deactivated with three-component kinetics: tau 1 = 20--45 ps, tau 2 = 100--300 ps, tau 3 greater than 500 ps. The process of the P700 photooxidation induced by the 650 nm exciting pulse was approximately monoexponential with tau equal to 15--30 ps. It is established that the P700 photooxidation is due to the efficient transfer of excitation energy from antenna chlorophylls to reaction centers.

[Technique for the determination of the quantum yield of the primary process in the course of photosynthesis energy transformation. III. Experimental data obtained for different photosynthetic organisms]. / Opredelenie kvantovogo vykhoda pervichnogo preobrazovaniia energii pri fotosintez III. Eksperimental'nye dannye dlia razlichnykh fotosinteziruiushchikh organizmov

A relative method in two modifications has been developed for determination of the quantum yield of primary photosynthesis energy conversion. The purple bacteria E. chaposhnikovii and Chr. minutissimum, R. rubrum chromatophores, cell extracts of E. shaposhnikovii, Rps. spheroides strains GA and R-26, pigment-protein complexes from green bacterium Chl. limicola and light subchloroplast particles, enriched in the photosystem I, were investigated. The quantum yields for all these objects were shown to be 90-98%. The accuracy of the relative method used is very high (within 2--4+). The photosynthetic units were proved to be of a multicentral type for all these systems. The quantum yield values permit estimation of the coefficient of efficiency of the primary conversion process as being approximately equal to 35-38% for bacteria and approximately equal to 50% plants.

[A discrepancy between the experimental and theoretical data on energy migration from B800 to B850 in LH-2 antennary complexes in purple bacteria]. / Nesootvetstvie éksperimental'nykh i teoreticheskikh dannykh po migratsii énergii ot B800 k B850 v antennykh kompleksakh LH-2 purpurnykh bakterii.

A discrepancy between the times of excitation transfer from B800 to B850 bacteriochlorophyll fractions in LH-2 complexes of purple bacteria was revealed. The experimental value (0.7-0.8 ps from literature sources) are at least four times lower than that (> 3.2 ps) calculated theoretically on the basis of recently obtained atomic structure of LH2. Possible reasons for this discrepancy are discussed.