Environmental Surveillance for Poliovirus and Other Enteroviruses: Long-Term Experience in Moscow, Russian Federation, 2004⁻2017.

Polio and enterovirus surveillance may include a number of approaches, including incidence-based observation, a sentinel physician system, environmental monitoring and acute flaccid paralysis (AFP) surveillance. The relative value of these methods is widely debated. Here we summarized the results of 14 years of environmental surveillance at four sewage treatment plants of various capacities in Moscow, Russia.

Consensus Integrase of a New HIV-1 Genetic Variant CRF63_02A1.

The high genetic variability of the human immunodeficiency virus (HIV-1) leads to a constant emergence of new genetic variants, including the recombinant virus CRF63_02A1, which is widespread in the Siberian Federal District of Russia. We studied HIV-1 CRF63_02A1 integrase (IN_CRF) catalyzing the incorporation of viral DNA into the genome of an infected cell. The consensus sequence was designed, recombinant integrase was obtained, and its DNA-binding and catalytic activities were characterized.

Inhibition of cyanobacterial photosynthetic activity by natural ketones.

Microbial volatiles have a significant impact on the physiological functions of prokaryotic and eukaryotic organisms. Various ketones are present in volatile mixtures produced by plants, bacteria, and fungi. Our earlier results demonstrated the inhibitory effects of soil bacteria volatiles, including ketones, on cyanobacteria.

Hydroxyectoine protects Mn-depleted photosystem II against photoinhibition acting as a source of electrons.

In the present study, we have investigated the effect of hydroxyectoine (Ect-OH), a heterocyclic amino acid, on oxygen evolution in photosystem II (PS II) membrane fragments and on photoinhibition of Mn-depleted PS II (apo-WOC-PS II) preparations. The degree of photoinhibition of apo-WOC-PS II preparations was estimated by the loss of the capability of exogenous electron donor (sodium ascorbate) to restore the amplitude of light-induced changes of chlorophyll fluorescence yield (∆F). It was found that Ect-OH (i) stimulates the oxygen-evolving activity of PS II, (ii) accelerates the electron transfer from exogenous electron donors (K[Fe(CN)], DPC, TMPD, Fe, and Mn) to the reaction center of apo-WOC-PS II, (iii) enhances the protective effect of exogenous electron donors against donor-side photoinhibition of apo-WOC-PS II preparations.

Elimination of proton donor strongly affects directionality and efficiency of proton transport in ESR, a light-driven proton pump from Exiguobacterium sibiricum.

ESR from Exiguobacterium sibiricum is a retinal protein which functions as a proton pump. Unusual feature of ESR is that a lysine residue is present at a site for the internal proton donor, which in other proton pumps is a carboxylic residue. Replacement of Lys96 with alanine slows reprotonation of the Schiff base by two orders of magnitude, indicating that Lys96 and interacting water molecules function as internal proton donor to the Schiff base.

Critical evaluation of electron transfer kinetics in P-F/F, P-F, and P-A Photosystem I core complexes in liquid and in trehalose glass.

This work aims to fully elucidate the effects of a trehalose glassy matrix on electron transfer reactions in cyanobacterial Photosystem I (PS I). Forward and backward electron transfer rates from A and A to F and charge recombination rates from A, A, A, F, and [F/F] to P were measured in P-F/F complexes, P-F cores, and P-A cores, both in liquid and in a trehalose glassy matrix at 11% humidity. By comparing CONTIN-resolved kinetic events over 6 orders of time in increasingly simplified versions of PS I at 480 nm, a wavelength that reports primarily A/A oxidation, and over 9 orders of time at 830 nm, a wavelength that reports P reduction and A oxidation, assignments could be made for nearly all of the resolved kinetic phases.

The Cyanotoxin BMAA Induces Heterocyst Specific Gene Expression in sp. PCC 7120 under Repressive Conditions.

Cyanobacteria synthesize neurotoxic β--methylamino-l-alanine (BMAA). The roles of this non-protein amino acid in cyanobacterial cells are insufficiently studied. During diazotrophic growth, filamentous cyanobacteria form single differentiated cells, called heterocysts, which are separated by approximately 12⁻15 vegetative cells.

Effect of inactivation of luxS gene on the properties of Serratia proteamaculans 94 strain.

The luxS gene is responsible for the synthesis of AI-2 (autoinducer-2), a signaling molecule that participates in quorum sensing regulation in a large number of bacteria. In this work, we investigated which phenotypes are regulated by luxS gene in Serratia proteamaculans 94, psychrotrophic strain isolated from spoiled refrigerated meat. AI-2 was identified in S.

Vaccine-associated paralytic poliomyelitis in the Russian Federation in 1998-2014.

Objectives: Different polio vaccination schemes have been used in Russia: oral polio vaccine (OPV) was used in 1998-2007 and inactivated polio vaccine (IPV) followed by OPV in 2008-2014. This article presents the characteristics of vaccine-associated paralytic poliomyelitis (VAPP) cases in Russia during this period.

Methods: VAPP cases were identified through the acute flaccid paralysis surveillance system, classified by the National Expert Classification Committee.

Electron-Phonon Coupling in Cyanobacterial Photosystem I.

One of the fundamental problems in biophysics is whether the protein medium at room temperature can be properly treated as a fluid dielectric or whether its dynamics is determined by a highly ordered molecular structure resembling the properties of crystalline and amorphous solids. Here, we measured the recombination between reduced A and the oxidized chlorophyll special pair P over a wide temperature range using preparations of photosystem I from the cyanobacterium Synechococcus sp. PCC 7002 depleted of the iron-sulfur clusters.

Reorganization energies of the electron transfer reactions involving quinones in the reaction center of Rhodobacter sphaeroides.

In framework of the continuum electrostatics theory, the reorganization energies of the electron transfers Q-Q (fast phase), Bph-Q, P-Q, and P-Q in the photosynthetic bacterial reaction center have been calculated. The calculations were based on the static dielectric permittivity spatial distribution derived from the data on the electrogenesis, with the corresponding characteristic times relatively close to the reaction times of Q-Q (fast phase) and Bph-Q but much shorter than those times of the latter two recombination reactions. The calculated reorganization energies were reasonably close to the experimental estimates for Q-Q (fast phase) and Bph-Q but substantially lower than those of P-Q and P-Q.

Cyclic electron transfer around Photosystem I mediated by 2,3-dichloro-1,4-naphtoquinone and ascorbate.

In this work, we investigated electron transport around the photosynthetic pigment-protein complex of Photosystem I (PS I) mediated by external high-potential electron carrier 2,3-dichloro-1,4-naphtoquinone (Cl NQ) and ascorbate. It has been demonstrated that the oxidized species of Cl NQ and ascorbate serve as intermediates capable of accepting electrons from the iron-sulfur cluster F of PS I. Reduced species of Cl NQ and ascorbate are oxidized by photooxidized PS I primary donor P700+ and/or by molecular oxygen.

Electrogenic reactions in Mn-depleted photosystem II core particles in the presence of synthetic binuclear Mn complexes.

An electrometrical technique was used to investigate electron transfer between synthetic binuclear manganese (Mn) complexes, designated M - 2 and M - 3, and the redox-active neutral tyrosine radical (Y) in proteoliposomes containing Mn-depleted photosystem II (PS II) core particles in response to single laser flashes. In the absence of Mn-containing compounds, the observed flash-induced membrane potential (ΔΨ) decay was mainly due to charge recombination between the reduced primary quinone acceptor Q and the oxidized Y. More significant slowing down of the ΔΨ decay in the presence of lower concentrations of M - 2 and M - 3 associated with electron donation from Mn in the Mn-binding site to Y indicates that these synthetic compounds are more effective electron donors than MnCl.

Effect of artificial redox mediators on the photoinduced oxygen reduction by photosystem I complexes.

The peculiarities of interaction of cyanobacterial photosystem I with redox mediators 2,6-dichlorophenolindophenol (DCPIP) and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) were investigated. The higher donor efficiency of the reduced DCPIP form was demonstrated. The oxidized form of DCPIP was shown to be an efficient electron acceptor for terminal iron-sulfur cluster of photosystem I.

Stress effects of cyanotoxin β-methylamino-L-alanine (BMAA) on cyanobacterial heterocyst formation and functionality.

Various species of cyanobacteria, diatoms and dinoflagellates are capable of synthesizing the non-proteinogenic neurotoxic amino acid β-N-methylamino-L-alanine (BMAA), which is known to be a causative agent of human neurodegeneration. Similar to most cyanotoxins, the biological and ecological functions of BMAA in cyanobacteria are unknown. In this study, we show for the first time that BMAA, in micromolar amounts, inhibits the formation of heterocysts (specialized nitrogen-fixing cells) in heterocystous, diazotrophic cyanobacteria [Anabaena sp.

Emergency Services of Viral RNAs: Repair and Remodeling.

Reproduction of RNA viruses is typically error-prone due to the infidelity of their replicative machinery and the usual lack of proofreading mechanisms. The error rates may be close to those that kill the virus. Consequently, populations of RNA viruses are represented by heterogeneous sets of genomes with various levels of fitness.

Three phases of energy-dependent induction of [Formula: see text] and Chl a fluorescence in Tradescantia fluminensis leaves.

In plants, the short-term regulation (STR, seconds to minute time scale) of photosynthetic apparatus is associated with the energy-dependent control in the chloroplast electron transport, the distribution of light energy between photosystems (PS) II and I, activation/deactivation of the Calvin-Benson cycle (CBC) enzymes, and relocation of chloroplasts within the plant cell. In this work, using a dual-PAM technique for measuring the time-courses of P photooxidation and Chl a fluorescence, we have investigated the STR events in Tradescantia fluminensis leaves. The comparison of Chl a fluorescence and [Formula: see text] induction allowed us to investigate the contribution of the trans-thylakoid pH difference (ΔpH) to the STR events.

Comparisons of Electron Transfer Reactions in a Cyanobacterial Tetrameric and Trimeric Photosystem I Complexes.

Photosystem I (PSI) is a Type-I reaction center and is the largest photosynthetic complex to be characterized. In cyanobacteria, PSI is organized as a trimer with a three-fold axis of symmetry. Recently, a tetrameric form of PSI has been identified in cyanobacteria.

Pressure for Pattern-Specific Intertypic Recombination between Sabin Polioviruses: Evolutionary Implications.

Complete genomic sequences of a non-redundant set of 70 recombinants between three serotypes of attenuated Sabin polioviruses as well as location (based on partial sequencing) of crossover sites of 28 additional recombinants were determined and compared with the previously published data. It is demonstrated that the genomes of Sabin viruses contain distinct strain-specific segments that are eliminated by recombination. The presumed low fitness of these segments could be linked to mutations acquired upon derivation of the vaccine strains and/or may have been present in wild-type parents of Sabin viruses.

Mechanism of adiabatic primary electron transfer in photosystem I: Femtosecond spectroscopy upon excitation of reaction center in the far-red edge of the Q band.

The ultrafast primary charge separation in Photosystem I (PS I) excited by femtosecond pulses centered at 720 and 760nm was studied by pump-to-probe laser spectroscopy. The absorbance in the red edge of PS I absorption spectrum has an unusual exponential dependence on wavelength. The cutoff of short wavelength components of 760nm pulse allows direct excitation of reaction center chlorophyll molecules without involvement of light-harvesting antenna.

Interaction of various types of photosystem I complexes with exogenous electron acceptors.

Interaction of photosystem I (PS I) complexes from cyanobacteria Synechocystis sp. PCC 6803 containing various quinones in the A-site (phylloquinone PhQ in the wild-type strain (WT), and plastoquinone PQ or 2,3-dichloronaphthoquinone Cl NQ in the menB deletion strain) and different numbers of FeS clusters (intact WT and F-core complexes depleted of F/F centers) with external acceptors has been studied. The efficiency of interaction was estimated by measuring the light-induced absorption changes at 820 nm due to the reduction of the special pair of chlorophylls (P) by an external acceptor(s).

Kinetic modeling of electron transfer reactions in photosystem I complexes of various structures with substituted quinone acceptors.

The reduction kinetics of the photo-oxidized primary electron donor P in photosystem I (PS I) complexes from cyanobacteria Synechocystis sp. PCC 6803 were analyzed within the kinetic model, which considers electron transfer (ET) reactions between P, secondary quinone acceptor A, iron-sulfur clusters and external electron donor and acceptors - methylviologen (MV), 2,3-dichloro-naphthoquinone (ClNQ) and oxygen. PS I complexes containing various quinones in the A-binding site (phylloquinone PhQ, plastoquinone-9 PQ and ClNQ) as well as F -core complexes, depleted of terminal iron-sulfur F /F clusters, were studied.

Acclimation of shade-tolerant and light-resistant Tradescantia species to growth light: chlorophyll a fluorescence, electron transport, and xanthophyll content.

In this study, we have compared the photosynthetic characteristics of two contrasting species of Tradescantia plants, T. fluminensis (shade-tolerant species), and T. sillamontana (light-resistant species), grown under the low light (LL, 50-125 µmol photons m s) or high light (HL, 875-1000 µmol photons m s) conditions during their entire growth period.

Respiratory complex II: ROS production and the kinetics of ubiquinone reduction.

Bovine heart mitochondrial respiratory complex II generates ROS, mostly as superoxide, at the rate of about 20% of that detected during simultaneous operation of complex I and II when oxidation of ubiquinol is prevented by myxothiazol. ROS generating activity at different fumarate/succinate concentrations ratio implies that an enzyme component with a midpoint potential 40mV more positive than that of fumarate/succinate couple is the donor for one-electron reduction of oxygen. This suggests that the iron-sulfur cluster(s) is(are) involved in superoxide formation.