Catalytic reduction of acetylene in the presence of molybdenum and iron clusters, including FeMo cofactor of nitrogenase

Acetylene was reduced by zinc amalgam in the presence of three synthetic polynuclear complexes: {[Mg₂Mo₈O₂₂(OMe)₆(MeOH)₄]⁻²·[Mg(MeOH)₆]²⁺}6MeOH (I), (Bu₄N)₂[Fe₄S₄(SPh)₄] (II), [Me₄N][VFe₃S₄Cl₃(DMF)₃]·2DMF (III) and the iron-molybdenum cofactor of nitrogenase Azotobacter vinelandii MoFe₇(S²⁻)₉·homocitrate, FeMo-co (IV). Thiophenol was found to greatly facilitate the reaction in the presence of complexes I, II, IV. The reaction is catalytic and for I and IV proceeds at the amalgam surface. Thiophenol seems to increase the adsorption of the complexes, serving as an electron bridge to transfer electrons to the catalyst. In the case of II a homogeneous reduction of the substrate occurs presumably after the cluster reduction at the surface and with III the catalytic reduction proceeds only under the action of sodium amalgam; no thiophenol cocatalytic action is observed. Relevance to N₂ enzymatic reduction is discussed.     

Effects of chronic imipramine treatment on behavior in mice of congenic strains AKR and AKR.CBA-D13Mit76 differing in the distal fragment of chromosome 13

Congenic mouse strain AKR.CBA-D13Mit76 carries the 59-70 cM fragment of chromosome 13 transferred from genome of cataleptic CBA/Lac strain to genome of AKR/J none-cataleptic strain. This fragment contains the major gene of predisposition to pinch-induced catalepsy. We investigated contribution of the fragment to regulation of sensitivity of catalepsy, sexual motivation and social investigation to classical tricyclic antidepressant imipramine. The sexual motivation was higher in AKR.CBA-D13Mit76 than in AKR mice. Chronic imipramine treatment (25 mg/kg) reduced it in AKR.CBA-D13Mit76 mice and had no effect on weakly expressed sexual motivation of AKR males. No significant effects of genotype or chronic imipramine treatment on characteristics of social interest were observed. Imipramine failed to alter catalepsy expression in AKR.CBA-DI3Mit76 mice. Possible molecular genetic mechanisms underlying difference in behavioral responses to antidepressant administration are discussed.     

Centric diatom algae (Centrophyceae) in waterbodies and water courses of the middle Irtysh basin

Light and scanning electron microscopy studies of centric diatoms of the plankton in the middle Irtysh River and waterbodies and water courses of its basin have revealed 21 taxa of Centrophyceae from 9 genera, including 14 new for the region. A revision of the species composition allowed us to specify and broaden the list of centric diatoms in the Omsk Priirtyshye up to 30 species.     

Phytoplankton of Lake Solenoye (Omsk) as a promising source of bioresources

The mass vegetation of the cyanobacteria Spirulina fusiformis Woronich. was discovered during examination of the shallow Lake Solenoye, situated in the territory of Omsk. Large resources of the raw spirulina biomass in summer make it possible to use the lake as a source of valuable raw material.     

5S rRNA-recognition module of CTC family proteins and its evolution

The effects of amino acid replacements in the RNA-binding sites of homologous ribosomal proteins TL5 and L25 (members of the CTC family) on ability of these proteins to form stable complexes with ribosomal 5S RNA were studied. It was shown that even three simultaneous replacements of non-conserved amino acid residues by alanine in the RNA-binding site of TL5 did not result in noticeable decrease in stability of the TL5-5S rRNA complex. However, any replacement among five conserved residues in the RNA-binding site of TL5, as well as of L25 resulted in serious destabilization or complete impossibility of complex formation. These five residues form an RNA-recognition module in TL5 and L25. These residues are strictly conserved in proteins of the CTC family. However, there are several cases of natural replacements of these residues in TL5 and L25 homologs in Bacilli and Cyanobacteria, which are accompanied by certain changes in the CTC-binding site of 5S rRNAs of the corresponding organisms. CTC proteins and specific fragments of 5S rRNA of Enterococcus faecalis and Nostoc sp. were isolated, and their ability to form specific complexes was tested. It was found that these proteins formed specific complexes only with 5S rRNA of the same organism. This is an example of coevolution of the structures of two interacting macromolecules.     

I/D polymorphism in the angiotensin-converting enzyme gene in men with myocardial infarction at young age]

The rate of D allele did not differ between patients with ischemic heart disease (IHD) who had myocardial infarction before the age 45, and healthy males. The DD genotype of the ACE gene was much more frequently encountered in the patients than in healthy males. The findings suggest that the DD genotype is an independent risk factor of the IHD and myocardial infarction in young patients.     

Stomatocysts of chrysophyte algae from bodies of water in territory near Irtysh river in Omsk Region and Lake Teletskoe in Gorny Altai,Russia

The distribution of stomatocysts of chrysophyte algae in the plankton of bodies of water of different types in the basin of the middle reach of the Irtysh (at the Omsk Region), as well as in the plankton and in fouling of the deep-water oligotrophic lake Teletskoe (Gorny Altai) has been considered. The classification of morphotypes of stomatocysts has been carried out. The number of morphotypes found in plankton samples from bodies of water of the middle Irtysh basin is 30 and, in Lake Teletskoe, 60. Four similar morphotypes of cysts were revealed for the bodies of water under investigation.     

Phytoplankton as an Indicator of Ecological State of the Saltaim-Tenis Lake System (Omsk Region)

Based on the data of long-term studies of phytoplankton, an assessment of the current ecological state and the direction of changes in the Saltaim-Tenis lake system (Omsk region) has been carried out. Species composition, structure, abundance, and dominant complexes of phytoplankton are described. The predominance of cyanobacteria in the formation of the population and the dominant phytoplankton complex is established. The trophic level of the lakes corresponds to the eutrophic and polytrophic water category. The saprobity index of water varies from the α-oligosaprobic to the β-mesosaprobic zone. Compared to the mid- 20th century, the ecological state of the lake system is stable.