Leaf Extracts of Invasive Woody Species Demonstrate Allelopathic Effects on the Growth of a Lawn Grass Mixture.

Biochemical composition was studied in the leaf litter of alien woody species included in the 100 most aggressive invasive species of Europe: Ailanthus altissima, Quercus rubra, Acer negundo, Robinia pseudoacacia, and Elaeagnus angustifolia. Using GC-MS, we detected 187 metabolites in the leaf litter, which are phenolic acids and their derivatives, carbohydrates and their derivatives, polyphenolic compounds, cyclic esters, glycosides, and amino acids and their derivatives. Species-specific metabolites were identified for each species. The main allelochemicals in the leaf litter extract of Q. rubra are determined mainly by the relative abundance of phenolic and fatty acids and their esters, whereas those in the leaf litter extract of R. pseudoacacia are determined by carbohydrates and their derivatives and ester of fatty acid, and those in the leaf litter extract of A. altissima are determined by glycosides. Profiles of macro- and microelements were characterized. It was found that aqueous extracts of leaf litter from all the invasive woody plants under study have a negative effect on the seed germination and initial growth of Vicia cracca and Avena strigosa used for the reclamation of disturbed urban and industrial lands. At the same time, V. cracca is potentially more sensitive.

The Effect of Whole Blood and Bone Marrow with the Addition of Pyrimidine-2,4(1h,3h)-dione Thietanyl Derivatives on Free Radical Oxidation.

BACKGROUND: It is relevant to study the general patterns and identify non-specific mechanisms of body protective and adaptive reactions violation, which can lead to the various pathological processes and develop principles for the correction of these disorders. One of the therapy and prevention directions is the search for new medicines. In recent years, new derivatives of pyrimidine bases have been synthesized and studied. Pyrimidine-based medicines have a membrane-stabilizing and immunomodulatory effect and can normalize metabolic disorders and increase the oxidative activity of leukocytes. Disruption of the free radical oxidation processes, the generation of reactive oxygen species and lipid peroxidation, including in whole blood and bone marrow, has gained importance in recent years. METHODS: Each reaction was monitored by thin layer chromatography. 1H, 13C, and 15N NMR spectra were recorded (chemical shifts were expressed as δ-values). We studied the effect of 6-methyl-3-(thietan- 3-yl)pyrimidine-2,4(1H,3H)-dione on the generation of reactive oxygen species (ROS) in the whole blood and bone marrow using the study of whole blood spontaneous and stimulated chemiluminescence (CL). CL methods make it possible to quickly and easily assess the studied material (whole blood, bone marrow) effect on free radical oxidation. Using CL methods, it is possible to reveal the presence of medicines' pro- or antioxidant properties, opening up new possibilities in the search for substances with antioxidant properties and comparing their activity. RESULTS: Alkylation of 6-methylpyrimidine-2,4(1H,3H)-dione by 2-chloromethylthiirane in protic solvents in the presence of alkali leads to the formation of an N-thietane derivative. NMR spectroscopy showed that 6-methylpyrimidine-2,4(1H,3H)-dione was alkylated at position 3. The oxidation reactions of N-(thietan-3-yl)pyrimidine-2,4(1H,3H)-dione were studied, and it was determined that, depending on the excess of the oxidizing agent and the duration of the process, N-(1-oxothietan-3-yl)- or N-(1,1-- dioxothietan-3-yl)pyrimidine-2,4(1H,3H)-diones were formed. The effects of free radical oxidation processes of new biologically active pyrimidine-2,4(1H,3H)-diones were studied. CONCLUSION: New pyrimidine-2,4(1H,3H)-diones increase the general adaptive capabilities of the body and have protective effects in extreme conditions.

Plant Invasion Research in Russia: Basic Projects and Scientific Fields.

This paper represents a review of comprehensive research into invasion biology done by Russian scholars for four decades. Invasion biology is a relatively new field of research focused on the study of alien plants, their behavior in new habitats and risks they pose to indigenous species. It is shown that over 40 years, single finds of alien plant species have transformed into a check-list of invasive species in Russia. The most significant invasion pathways were identified, and the rate of microevolutional changes in plant species in their secondary distribution range was determined. Since the most active alien species disperse without regard to national borders, international cooperation is crucial in joint studies of invasive species.