Structural insight into the molecular basis of polyextremophilicity of short-chain alcohol dehydrogenase from the hyperthermophilic archaeon Thermococcus sibiricus

Biochemical analysis of enantioselective short-chain alcohol dehydrogenase from the hyperthermophilic archaeon Thermococcus sibiricus (TsAdh319) revealed unique polyextremophilic properties of the enzyme – half-life of 1 h at 100 °C, tolerance to high salt (up to 4 M) and organic solvents (50% v/v) concentrations. To elucidate the molecular basis of TsAdh319 polyextremophilicity, we determined the crystal structure of the enzyme in a binary complex with 5-hydroxy-NADP at 1.68 Å resolution. TsAdh319 has a tetrameric structure both in the crystals and in solution with an intersubunit disulfide bond. The substrate-binding pocket is hydrophobic, spacious and open that is consistent with the observed promiscuity in substrate specificity of TsAdh319. The present study revealed an extraordinary number of charged residues on the surface of TsAdh319, 70% of which were involved in ion pair interactions. Further we compared the structure of TsAdh319 with the structures of other homologous short-chain dehydrogenases/reductases (SDRs) from thermophilic and mesophilic organisms. We found that TsAdh319 has the highest arginine and aspartate + glutamate contents compared to the counterparts. The frequency of occurrence of salt bridges on the surface of TsAdh319 is the highest among the SDRs under consideration. No differences in the proline, tryptophan, and phenylalanine contents are observed; the compactness of the protein core of TsAdh319, the monomer and tetramer organization do not differ from that of the counterparts. We suggest that the unique thermostability of TsAdh319 is associated with the rigidity and simultaneous “resilience” of the structure provided by a compact hydrophobic core and a large number of surface ion pairs. An extensive salt bridge network also might maintain the structural integrity of TsAdh319 in high salinity.     

Duration of Voluntary Breath Holding and Blood Parameters

Stange's and Genci's functional tests performed at rest and during exercise and blood tests have shown that the duration of voluntary breath holding depends on appearance in the blood of hypoxia, hypercapnia, and acidosis signs only after the influence of fatigue of respiratory muscles and respiratory center has become insufficient.     

The role of interphase prenucleolar bodies in the recovery of the nucleolar structure after reversible hypotonic treatment

Interphase prenucleolar bodies are globular bodies which accumulate in large numbers in the nucleoplasm of cultivated cells after hypotonic treatment and subsequent return to isotonic conditions; detailed studies of the role of these structures in the recovery of the nucleolus have not yet been performed. The limited mobility of interphase pronucleoli within the nucleus has been demonstrated. Exchange of the major nucleolar protein B23 between prenucleolar bodies and the surrounding nucleoplasm, rather than stable binding of this protein to the prenucleolar bodies, has been demonstrated using fluorescence recovery after photobleaching method. Gradual accumulation of B23 in the recovering nucleolus with concomitant disappearance of prenucleolar bodies has been demonstrated.     

Pathology of the anterior cingulate cortex in obsessive-compulsive disorder

In this article, the characteristics of the functional activity of the anterior cingulate cortex (ACC), a key element of the neuroanatomical error detection system of the brain in drug-resistant forms of obsessive-compulsive disorder (OCD) are discussed on the basis of both original and published data. Available data indicate the presence of a functional deficit zone in the ACC during PCD. This fact suggests that the functions of the ACC in OCD patients are partially redistributed between other brain areas. Thus, in contrast to the previously accepted ideas, the target of stereotactic surgery for OCD is a pathologically altered brain region. Probably, this explains the fact that the operation does not lead to significant changes in the patient’s psyche. The pathological reorganization of the functional activity of the brain in OCD remains unclear and requires further investigation.     

A novel bacterium carrying out anaerobic ammonium oxidation in a reactor for biological treatment of the filtrate of wastewater fermented sludge

A new genus and species of bacteria capable of ammonium oxidation under anaerobic conditions in the presence of nitrite is described. The enrichment culture was obtained from the Moscow River silt by sequential cultivation in reactors with selective conditions for anaerobic ammonium oxidation. Bacterial cells were coccoid, ～0.4 × 0.7 μm, with the intracellular membrane structures typical of bacteria capable of anaerobic ammonium oxidation (anammoxosome and paryphoplasm). The cells formed aggregates 5–25 μm in diameter (10 μm on average). They were readily adhered to solid surfaces. The cells were morphologically labile: they easily lost their content and changed their morphology during fixation for electron microscopy. The organism was capable of ammonium oxidation with nitrite. The semisaturation constants Ks for nitrite and ammonium were 0.38 mg N-NO₂/L and 0.41 mg N-NH₄/L, respectively. The maximal nitrite concentrations for growth were 90 and 75 mg N-NO₂/L for single and continuous application, respectively. The doubling time was 32 days, μ_max = 0.022 day^?1, the optimal temperature and pH were 20°C and 7.8–8.3, respectively. According to the results of 16S rRNA gene sequencing, the bacterium was assigned to a new genus and species within the phylum Planctomycetes. The proposed name for the new bacterium is Candidatus Anammoximicrobium moscowii gen. nov., sp. nov. (a microorganism carrying out anaerobic ammonium oxidation, isolated in the Moscow region).     

Elasticity and physico-chemical properties during drinking water biofilm formation

Atomic force microscope techniques and multi-staining fluorescence microscopy were employed to study the steps in drinking water biofilm formation. During the formation of a conditioning layer, surface hydrophobic forces increased and the range of characteristic hydrophobic forces diversified with time, becoming progressively complex in macromolecular composition, which in return triggered irreversible cellular adhesion. AFM visualization of 1 to 8 week drinking water biofilms showed a spatially discontinuous and heterogeneous distribution comprising an extensive network of filamentous fungi in which biofilm aggregates were embedded. The elastic modulus of 40-day-old biofilms ranged from 200 to 9000 kPa, and the biofilm deposits with a height >0.5 μm had an elastic modulus <600 kPa, suggesting that the drinking water biofilms were composed of a soft top layer and a basal layer with significantly higher elastic modulus values falling in the range of fungal elasticity.     

Frequency and causes of prevalence of p.Arg894* mutation in CLCN1 gene responsible for development of thomsen’s and becker’s myotonias in russian population

Thomsen’s (TM) and Becker’s (BM) myotonias are nondystrophic myotonias. At present, 150 mutations in the CLCN1 gene, which results in the development of TM and BM, have been described. The c.2680C>T (p.Arg894*) is the most common mutation. In the Northern Scandinavian countries, the population frequency of this mutation is 0.87%, while in the Russian Federation, it is equal to 1.2% (this study). Based on the results of a molecular-genetic analysis of CLCN1 gene in patients with nondystrophic myotonias, the calculated frequency of TM and BM in Russia is 1: 8165 and 1: 710, respectively. We have conducted haplotype analysis using microsatellite markers and intragene SNP, which has shown that the prevalence of p.Arg894* mutation in Russia results from the founder effect, and the time of its scattering is 3680 ± 1240 years.     

Complex Molecular Diagnostics of Hemophilia A in Russian Patients

Russian Journal of Genetics - Hemophilia A is a frequent X-linked recessive blood clotting disorder. It is caused by mutations in the F8 gene (locus Xq28) and affects 1 in 5000 newborn boys. The...     

Transthyretin gene V30M,H90N,and (del9) mutations in cardiomyopathy patients from St. Petersburg

A search of transthyretin (TTR) gene mutations was performed in patients with cardiomyopathies from St. Petersburg. Mutations H90N, V30M and deletion (del9) of nucleotides GACTTCTCC in position 6776 from the start codon of the TTR gene (in position 98782 according to reference sequence AC079096 (NCBI) was found. The H90N mutation in the third exon of TTR gene was detected in a son of a cardiomyopathy patient and in his mother, which lacked any clinical manifestations. Mutation V30M in exon 2 of TTR gene was found in heterozygous in one of the probands. Deletion (del9) was revealed in a patient with cardiomyopathy and in his two daughters from different marriages, who had no clinical manifestations of the disease. All the mutations revealed in this study were previously identified in other populations.