Search

Currently, the problem of reducing the effectiveness of antimicrobial preparations—both antibiotics and fungicides—is becoming more acute in medicine, veterinary medicine and agriculture. Therefore, one of the promising areas of modern scientific study is the search for new means of combating pathogenic microorganisms, including herbal preparations. In recent years, it has been revealed that the ubiquitous medicinal plant Chenopodium album L. has a wide range of biological activities (antimicrobial, antioxidant, anthelmintic, anticancer, etc.). This review discusses the potential of antibacterial and antifungal activity of various C. album extracts against bacteria and fungi pathogenic to both humans and plants. Possible mechanisms of the antimicrobial action of C. album and factors regulating these properties are also considered. [ABSTRACT FROM AUTHOR]

The low rainfall and high temperatures of arid and semi-arid zones promote high salinity and this salinity has become an important factor limiting the growth of salt-sensitive plants. More than 800 million hectares of land throughout the world are salt affected including 39.2 million hectares in Russia, while in Kazakhstan, salinized soils occupy about 40% of the country's area. Phytoremediation with the use of halophytes can be a cost-effective and environmentally sound technology for the remediation of salt-impacted sites. Halophytes could be valuable sources of novel endophytic isolates that can be used to overcome various biotic and abiotic stresses such as salinity. Endophytes can contribute to plant health impeded by salinity stress, by influencing phytohormonal levels and signaling, contributing to homeostasis maintenance of toxic ions under salinity stress, enhancing photosynthesis, and contributing to biomass production and allocation. The review is devoted to halophytic plants and endophytic microorganisms inhabiting them. Data on the possibility of using halophytes for remediation of saline soils are presented. The definitions of which plants can be considered halophytes are given, the mechanisms of adaptation of halophytes to salinity conditions are described. Data on the use of halophytes for the production of agricultural and other valuable products on saline soils are presented. The list of halophytes of practical value and promising for agricultural use on saline soils of Russia and Kazakhstan is given. Endophytic bacteria inhabiting halophytic plants are described and the results of their practical use for obtaining agricultural products on saline soils and phytoremediation of highly saline soils are presented. The selection of compatible and effective plant-microbial systems and their use to combat abiotic and biotic stresses of plants and produce agricultural products on saline soils is a promising scientific direction. This will make it possible to develop methodological approaches to solving one of the global problems of agricultural production—salinization and degradation of agricultural lands and obtaining products on them and to offer practical ways to implement it. [ABSTRACT FROM AUTHOR]

Identification and analysis of the melanin biosynthesis gene in the Sinorhizobium meliloti CA15-1 strain were carried out. Tn5 mutants, which lost the ability to synthesize melanin, were obtained. Molecular biological analysis of the mepA gene encoding tyrosinase was performed. In contrast to other members of the Rhizobiacea group, the identical structure of the mepA locus was revealed for all strains of nodule bacteria of the Sinorhizobium genus. Phylogenetic analysis indicated that horizontal transfer of the mepA gene occurred in the course of evolution of bacterial tyrosinases. At the same time, the closely related members of nodule bacteria “acquired” this gene from different sources. Analysis of symbiotic properties of the Mep- mutants of the CA15-1 strain showed that melanin did not affect the ability to go into an efficient symbiosis with alfalfa. Most probably, it is important only at the stages of adaptation of the free-living cells in the environment. [ABSTRACT FROM AUTHOR]

The use of a complex biological product (CBP) based on native microbiological consortiums of coniferous forest litter accelerated the composting process of coniferous wood waste. The contribution of micromycetes and bacteria to the activation of coniferous wood waste composting processes using the different fertilizers rates was studied. A fractal analysis has confirmed the formation of a micromycetes-bacterial system in the treatment with optimal rates of NPK and CBP. In this case the better decomposition of wood waste was observed. It was noted that micromycetes of the genus Penicillium dominated in the composts obtained with CBP addition. This compost was not phytotoxic. Thus, for coniferous sawdust decomposition and its further humification, it is necessary to use both micromycetes and bacteria. The use of organic material resulting from wood waste decomposition with CBP and optimal rates of NPK is an effective way to increase the content of organic substances in soils and their potential fertility. [ABSTRACT FROM AUTHOR]

The goat's rue rhizobia (Neorhizobium galegae) represent a convenient model to study the evolution and speciation of symbiotic bacteria. This rhizobial species is composed of two biovars (bv. orientalis and bv. officinalis), which form N2-fixing nodules with certain species of goat's rue (Galega orientalis and G. officinalis). The cross-inoculation between them results in the formation of nodules unable to fix nitrogen. On the basis of the data on the whole-genome sequencing, we studied the nucleotide polymorphism of 11 N. galegae strains isolated from the North Caucasus ecosystems, where G. orientalis has higher diversity than G. officinalis. The low level of differences in the polymorphism within the group of the sym genes in comparison with the nonsymbiotic genes can be associated with the active participation of host plants in the evolution of rhizobia. The intragenic polymorphism of bv. orientalis proved to be significantly higher than that of bv. officinalis. The level of polymorphism of nonsymbiotic genes was lower than that of the symbiotic genes, which are functionally more homogeneous. The divergence of the nitrogen fixation genes (nif/fix) is more pronounced than that of the nodule formation genes (nod) in the N. galegae biovars. These facts indicate the leading role of the host-specific nitrogen fixation in the evolution of the studied rizhobial species. [ABSTRACT FROM AUTHOR]