Inside and outside of virus-like particles HBc and HBc/4M2e: A comprehensive study of the structure.

Hepatitis B virus core antigen (HBc) with the insertion of four external domains of the influenza A M2 protein (HBc/4M2e) form virus-like particles whose structure was studied using a combination of molecular modeling and cryo-electron microscopy (cryo-EM). It was also shown that self-assembling of the particles occurs inside bacterial cells, but despite the big inner volume of the core shell particle, purified HBc/4M2e contain an insignificant amount of bacterial proteins. It was shown that a fragment of the M2e corresponding to 4M2e insertion is prone to formation of amyloid-like fibrils. However, as the part of the immunodominant loop, M2e insertion does not show a tendency to intermolecular interaction. A full-atomic HBc-4M2e model with the resolution of about 3 Å (3.13 Å for particles of Т = 4 symmetry, 3.7 Å for particles of Т = 3 symmetry) was obtained by molecular modeling methods based on cryo-EM data.

Cold and distant: structural features of the nucleoprotein complex of a cold-adapted influenza A virus strain.

Two influenza A nucleoprotein variants (wild-type: G102R; and mutant: G102R and E292G) were studied with regard to macro-molecular interactions in oligomeric form (24-mers). The E292G mutation has been previously shown to provide cold adaptation. Molecular dynamics simulations of these complexes and trajectory analysis showed that the most significant difference between the obtained models was distance between nucleoprotein complex strands. The isolated complexes of two ribonucleoprotein variants were characterized by transmission electron microscopy and differential scanning fluorimetry (DSF). Presence of the E292G substitution was shown by DSF to affect nucleoprotein complex melting temperature. In the filament interface peptide model, it was shown that the peptide corresponding in primary structure to the wild-type NP (SGYDFEREGYS) is prone to temperature-dependent self-association, unlike the peptide corresponding to E292G substitution (SGYDFGREGYS). It was also shown that the SGYDFEREGYS peptide is capable of interacting with a monomeric nucleoprotein (wild type); this interaction's equilibrium dissociation constant is five orders of magnitude lower than for the SGYDFGREGYS peptide. Using small-angle neutron scattering (SANS), the supramolecular structures of isolated complexes of these proteins were studied at temperatures of 15, 32, and 37 °C. SANS data show that the structures of the studied complexes at elevated temperature differ from the rod-like particle model and react differently to temperature changes. The data suggest that the mechanism behind cold adaptation with E292G is associated with a weakening of the interaction between strands of the ribonucleoprotein complex and, as a result, the appearance of inter-chain interface flexibility necessary for complex function at low temperature.Communicated by Ramaswamy H. Sarma.

[Fecal microbiota transplantation for graft-versus-host disease in children and adults: methods, clinical effects, safety].

AIM: Was to evaluate clinical efficacy, adverse events and changes in the gut microbiome after fecal microbiota transplantation (FMT) in patients with gastrointestinal (GI) form of graft-versus-host disease (GVHD). MATERIALS AND METHODS: The prospective single-center study in R.M. Gorbacheva institute included 27 patients with GI GVHD after allogeneic stem cell transplantation. 19 patients received FMT, 8 patients received placebo. Clinical scales for GI autoimmune diseases were used to evaluate response. Microbiome alterations were assessed with multiplex PCR. RESULTS: After FMT higher overall bacterial mass (р=0.00088), higher bacterial numbers ofBifidobacteriumspp. (р=0.021),Escherichia coli(р=0.049) andBacteroides fragilisgr. (р=0.000043) compared to placebo group. Also higher bacterial mass was observed in patients with clinical response (р=0.0057). The bacterial mass after procedure in non-responders was compared to the placebo group (р=0.31). Partial response of GVHD was achieved faster in the FMT group compared to placebo (median 4 days vs 48 days,p=0.014). Complete response was observed in 8 (42%), 14 (74%) and 16 (84%) at 30, 60 and 90 days respectively, while in the placebo group only 0%, 1 (13%) and 4 (50%) achieved complete response at the same time points. The incidence and severity of adverse events was comparable between FMT and the placebo group. CONCLUSION: FMT in patients with refractory GI GVHD was associated with favorable clinical outcomes and recovery in certain marker bacterial populations. Multiplex PCR can be used to assess an engraftment of a donor microbiota. FMT in GI GVHD was not associated with life-threatening adverse events, but further studies are required to validate clinical efficacy.

Characterization of the cleaved edge cross section of the heterostructures with GaMnAs layer by the confocal micro-Raman spectroscopy.

Confocal micro-Raman spectroscopy was used to measure cross-section linescans of the cleaved edge of heterostructures involving a GaMnAs layer. The investigations revealed a shift of the TO mode in the compressed GaMnAs layer to high frequencies relative to the TO GaAs mode in the substrate and to low frequencies in the tensile GaMnAs layers. These results are in agreement with the different manifestations of the anomalous Hall effect in the GaMnAs layers, with either compressive or tensile strains. It is shown that Raman spectroscopy is an appropriate method for the investigation of cross-sectional semiconductor heterostructures whose total thickness is comparable to the size of the analyzing laser spot.

Effects of Experimental Coma on the Expression of Bcl-2 Protein and Caspases 3 and 9 in Rat Brain.

We performed immunohistochemical analysis of the expression of caspases 3, 9 and bcl-2 protein in rat brain at various terms after administration of LD50 of sodium thiopental. Expression of the specified apoptosis markers was found in the sensorimotor cortex and hippocampus (dentate gyrus and CA2 region).

[On epigenetic regulation of process of formation of long-term memory].

The review summarizes current concepts on role of several covalent posttranslation chromatin modifications in the process of memory formation in vertebrate and invertebrate animals. There is described a chain of intracellular events from activation of receptors and signal pathways to change of the functional state of genome.

Disturbances in cervico-vestibulo-oculomotor interaction in patients with late stages of Parkinson disease.

Cervico-vestibulo-oculomotor interactions in patients with Parkinson disease stages III-IV and healthy subjects were studied in horizontal head movement and gaze fixation on immobile and mobile targets. Significant changes in the amplitude, head movement frequency and asymmetry, eye movement amplitude, and phase mismatch between head and eye movements were revealed in patients in comparison to the normal.

[The morphological basis of conditioned reflex in the honeybee Apis mellifera L].

A review. Works related to research into the neuroanatomical basis of associative learning in the honeybee (proboscis extension reflex) are summarized. Data on the brain organization of the honeybee are presented. The parallel neural pathways of conditioned and unconditioned stimuli are shown. Contribution of different brain structures and identified neurons (VUMmx1, PE1) in the formation of the proboscis extension reflex are discussed.

[Changing of filamentation dynamics of RecA protein, induced by D112R amino acid substitution or ATP to dATP replacement, results in filament steadiness TO THE RecX protein action].

It is known that RecX is a negative regulator of RecA protein. We found that the mutant RecA D112R protein exhibits increased resistance to RecX protein comparatively to wild-type RecA protein in vitro and in vivo. Using molecular modeling we showed, that amino acid located in position 112 can not approach RecX closer than 25-28 angstroms. Thus, direct contact between amino acid and RecX is impossible. RecA D112R protein more actively competes with SSB protein for the binding sites on ssDNA and, therefore, differs from the wild-type RecA protein by dynamics of filamentation on ssDNA. On the other hand, after the replacement of ATP by dATP, the wild-type RecA protein, changing the dynamics of filamentation on ssDNA, also becomes more resistant to RecX. Based on these data it is concluded that the dynamics of filamentation has a great, if not dominant role in the stability of RecA filament to RecX relative to the role of RecA-RecX protein-protein interactions discussed earlier. We also propose an improved model of regulation of RecA by RecX protein, where RecA filament elongation along ssDNA is blocked by RecX protein on the ssDNA region, located outside the filament.

Mechanisms of cervico-vestibular-oculomotor disorders at the early stages of Parkinson's disease.

We studied the interaction of the oculomotor, cervical, and vestibular systems using a specially developed technique. A series of two tests were performed on 26 healthy subjects and 42 patients with stages I-II Parkinson's disease receiving and not receiving treatment. In coordinated tests, all amplitude-time characteristics of patients significantly differed from those in healthy subjects. Possible mechanisms of cervico-vestibular-oculomotor disorders are discussed.

Impairment of gaze fixation and holding in patients with neurocirculatory asthenia syndrome and associated vestibular dysfunction.

The study was performed with a hardware-software complex for the monitoring of human motor functions. Saccadic eye movements and vestibulo-oculomotor interactions were studied in patients with neurocirculatory asthenia and associated vertigo. No changes in saccadic eye movements were found in these patients. Abnormalities of cervico-vestibulo-oculomotor interactions were manifested in the impairment of gaze fixation and holding.

[The effect of point amino acid substitutions in an internal alpha-helix on thermostability of Aspergillus awamori X100 glucoamylase].

Conformational flexibility of alpha-helices in glucoamylase of the fungus Aspergillus awamori was studied by molecular dynamics methods. Several amino acid substitutions (G127A, P128A, I136L, G137A, and G139A) optimizing intrinsic interactions in one of the alpha-helices (D) within the hydrophobic core of this protein were constructed and studied. It was found that these point mutations had different effects on the glucoamylase thermal inactivation constant. Unlike amino acid substitution P128A and substitutions G137A and A246C, I136L and G139A displayed a pronounced additive thermostabilizing effect.

[Nutrition at the preschool institutions: organizational aspects].

Three meals a day with a high-calorie afternoon snack (instead of afternoon snack and supper) moved an hour later than usual are most adequate and physiological for preschool children who stay at a preschool institution for 10.5 to 12 hours. This is achieved by a reduced food assortment that covers 85% of daily energy losses in a child. Control of nutrition adequacy in the preschool institution by a bookkeeping cumulative list is rather effective and informative. A month official control of the nutritive value of a mean daily menu apportionment does not achieve the main objective of a control - to maintain the nutrition balance of meals and their correction with foods. While republishing normative documents on nutrition at the preschool institutions, sanitary epidemiological surveillance bodies wish to be overcautious, by expanding the list of products and dishes prohibited for use, thus releasing the workers of the nutrition unit of a preschool institution from responsibility for safe nutrition, but this frequently causes damage to nutrition itself.

Probing the structure of F-actin: cross-links constrain atomic models and modify actin dynamics.

Cross-links between protomers in F-actin can be used as a very sensitive probe of both the dynamics and structure of F-actin. We have characterized filaments formed from a previously described yeast actin Q41C mutant, where disulfide bonds can be formed between the Cys41 that is introduced into subdomain-2 and Cys374 on an adjacent protomer. We find that the distribution of cross-linked n-mers shows no cooperativity and corresponds to a random probability cross-linking reaction. The random distribution suggests that disulfide formation does not cause a significant perturbation of the F-actin structure. Consistent with this lack of perturbation, three-dimensional reconstructions of extensively cross-linked filaments, using a new approach to helical image analysis, show very small structural changes with respect to uncross-linked filaments. This finding is in conflict with refined models but in agreement with the original Holmes et al. model for F-actin. Under conditions where 94 % of the protomers are linked by disulfide bonds, the distribution of filament twist becomes more heterogeneous with respect to control filaments. A molecular model suggests that strain, introduced by the disulfide, is relieved by increasing the twist of the long-pitch actin helices. Disulfide formation makes yeast actin filaments approximately three times less flexible in terms of bending and similar, in this respect, to vertebrate skeletal muscle F-actin. These observations support previous reports that the rigidity of F-actin can be controlled by the position of subdomain-2, and that this region is more flexible in yeast F-actin than in skeletal muscle F-actin.

[Study of the impact of experimental curriculum education on the health status of gymnasium students]. / Izuchenie vliianiia obucheniia po éksperimental'noi programme na sostoianie zdorov'ia gimnazistov.

The intensified innovative curriculum at new type schools (gymnasia) has no negative impact on pupil's health provided that an educational process is correctly designed and there is sufficient motor activity. Traditional health indices of a children's collective body, such as physical development, morbidity, etc.) are a reliable criterion for the realization of their adaptive capacities under the influence of unfavorable environmental factors.

[New aminooxy analogs of biogenic polyamines]. / Novye aminookisianalogi biogennykh poliaminov.

A series of structural analogs of putrescine, spermidine, and spermine with the aminomethylene fragment substituted by the aminooxy group was suggested. The synthesis of the new aminooxy analogs of spermine was described. Biochemical aspects of the activity of the aminooxy analogs of polyamines were discussed in respect of their selective inhibition of normal and leukemic cells.

[Study of the anticarcinogenic characteristics of the trace element, selenium, sanitary-hygienic experiment]. / Issledovanie antikantserogennykh svoistv mikroélementa selena v sanitarno-gigienicheskom éksperimente.

Enrichment of rat daily diets by 1-2 (up to 5) mg selenium increased nonspecific resistance of animals to ionizing radiation. Incidence of mammary, pituitary, and thyroid tumors as well as of leukemia were lower as compared with control animal group given no selenium.

[Comparative evaluation of cancerogenic risk of radiation and air pollution by coal ashes and benzo(a)pyrene]. / Sravnitelnaia otsenka kantserogennogo riska pri vozdeistvii radiatsii i zagriaznenii atmosfernogo vozdukha ugolnoi zoloi i benz(a)pirenom.

Experiments were made with 800 white outbred mice inhaling benzo [a] pyrene (BP) and volatile coal ash for a long time. Experiments showed that BP is 10-1000-fold more carcinogenic than volatile coal ash. BP inhalation at a sanitary standard level (0.1 microgram/100 m3 of air) corresponds to equivalent risk of total gamma-emission about 2 Sv. Coal ash inhalation in concentration 0.05 mg/m3 corresponds to the same equivalent risk as for the dose 0.05 Sv.