Vol 476, No 1 (2017)

On the basis of the structure of beta-turn of loop 2 of brain-derived neurotrophic factor (BDNF), its new dimeric dipeptide mimetic bis-(N-hexanoyl-L-seryl-L-lysine) hexamethylenediamide (GTS-201) was created. It activated TrkB and Erk, did not activate Akt, and exhibited neuroprotective activity in vitro at concentrations of 10^–5–10^–8 M. Unlike the mimetics that activate Erk and Akt, GTS-201 did not exhibit antidepressant properties. For the manifestation of the antidepressant activity of BDNF mimetics, the activation of its both major signaling pathways is required.

We found a two-fold increase in the productivity of baker’s yeast grown on a nutrient mixture prepared in light water with a D₂O content (127 ppm) smaller than in the distilled water (150 ppm). The number of water monomers that provides the biosynthetic activity (water transport through membrane channels) of yeast cells with an increased CO₂ yield was determined for the first time. We established that the selectivity of cell membrane channels in water of different composition depends not only on the motion of ortho-and para-spin H₂O isomers in solution, as was shown earlier, but also on the concentration of D₂O.

The dynamics of expression of PR1 and PR6 genes, which are involved in the defense response of plants infected with the root-knot nematode Meloidogyne incognita, was studied in the “tomato–root-knot nematode” parasitic system. The invasion of the resistant plants was accompanied by an increased accumulation of transcripts of PR genes, which reflects their fast response to the penetration of nematode juveniles with subsequent development of an adequate defense response. In the susceptible plants, changes in the PR1 and PR6 gene activity induced by the nematode invasion were insignificant, which may be one of the causes of the disease. An exogenous salicylic acid treatment of the susceptible plants increased the PR1 and PR6 genes activity and led to the development of resistance of these plants to nematode invasion.

Low-molecular-weight compounds with anticoagulant activity were isolated from the scorpion Heterometrus laoticus venom. The determination of the structure of the isolated compounds by nuclear magnetic resonance and mass spectrometry showed that one of the isolated compounds is adenosine, and the other two are dipeptides leucyl-tryptophan and isoleucyl-tryptophan. The anticoagulant properties of adenosine, which is an inhibitor of platelet aggregation, is well known, but its presence in scorpion venom is shown for the first time. The ability of leucyl-tryptophan and isoleucyl-tryptophan to slow down blood clotting and their presence in scorpion venom are also established for the first time.

The incubation in deuterium-depleted medium of mitochondria isolated from the liver of rats that consumed drinking diet with depleted deuterium (46 ppm) revealed a higher (by 35%) generation of hydrogen peroxide in comparison with the mitochondria (isolated from the liver of rats that consumed drinking diet with 152 ppm deuterium) incubated in medium that contained 152 ppm deuterium. Succinate addition to the reaction system led to an increase in the production of hydrogen peroxide in isolated mitochondria by 44–81%, whereas the difference in the generation of H₂O₂ between the organelles incubated in mediums 46 and 152 ppm was reduced by 14%. The revealed change in the functional activity of mitochondria suggests the ability of the organism to adapt to the deuterium-depleted drinking diet, which is probably due to the formation of the D/H isotope transmembrane gradient.

The activity of catalase and superoxide dismutase in the roots of susceptible plants and plants exposed to alternating temperatures, which were infected with the phytoparasitic nematode G. rostochiensis, was studied. It was found that, throughout the invasion period, the plants susceptible to invasion exhibited a high activity of these enzymes, which allowed them to maintain an active defense against the oxidative stress caused by the invasion and subsequent life activity of larvae. For the plants exposed to alternating temperatures, a decrease in the activity of catalase and superoxide dismutase at the early stages of invasion and an increase in the activity of these enzymes at the later stages was detected.

This is the first study to show that the formation of 14β-hydroxylated derivatives of taxa-4(20),11-diene is a specific feature of in vitro cultured dedifferentiated yew cells that distinguishes them from intact plant cells. This may be due to a lower toxicity of the 14-OH taxoids for proliferating plant cells compared to the 13-OH derivatives.