Irina Nikolayevna Egorova

Studying the secondary structure of ITS2 is a key tool in molecular systematics, expanding the capabilities of primary nucleotide sequence analysis. In most eukaryotes, ITS2 forms a conserved pattern of four helices, I–IV. An accurate model of this structure is critical for phylogeny and species delimitation. Analysis of compensatory substitutions (CBCs) in ITS2 is a necessary element of the species identification algorithm. Studies of various taxonomic groups of green microalgae have revealed potential problems and limitations of using CBCs in analysis. Modeling the secondary structure of ITS, searching for CBCs, and understanding the evolutionary history of specific taxa of microalga are important aspects of species identification.

SUMMARY: During soil‐algological research in the mountainous area of Asian Russia near Lake Baikal, we isolated a new chlamydomonad strain, IRK–A 362. Morphological and ultrastructural features of this alga have been studied using light and transmission electron microscopy (TEM). Phylogenetic reconstructions were inferred based on the small subunit rDNA (18S rDNA), the internal transcribed spacers (ITS1‐ITS2), and the plastid‐encoded elongation factor Tu ( tuf A). Secondary structures of ITS1 and ITS2 were analyzed and compensatory base changes (CBCs) were investigated. Based on the obtained results, including molecular, morphological, and ultrastructural features, we describe the strain IRK–A 362 as the new species Edaphochlamys sudakovae sp. nov.

The article presents the results of studies of herbaceous plant communities in the Baikal basin, with the significant participation of the diazotrophic cyanoprokaryota Nostoc commune. The territory of the investigation is located at the foot of the Primorskiy range. There are developed mountain, typical steppe, and meadow communities on chestnut soils. A high content of carbonates was found in the soils, and the pH of the upper horizons varied from slightly acidic to alkaline. The composition of algae and cyanoprokaryota species living in and on soils has been revealed. In total, in steppe and meadow communities we identified 71 species from five divisions: Cyanoprokaryota – 27, Bacillariophyta – 4, Ochrophyta – 3, Chlorophyta – 34, and Charophyta – 3. 58 species have been found in steppe communities, 40 in meadow. A predominance of cyanoprokaryota and green algae was noted. The composition of the studied phototrophic species in steppe communities differed significantly from that of the meadow. In steppe communities Nostoc commune formed macroscopic colonies, and its biomass production was low (about 2 g/m2) comparable to that of a number of Asia arid territories. The N. commune biomass formation was higher on the mountain slope and at its foot, where higher density of soil composition, lower field humidity, as well as an increased content of calcium, magnesium, and sodium was found in soils. The N. commune biomass was reduced in the site at a distance from the mountain slope where the content of the above elements was lower. The regular sampling of macrocolonies had a negative impact on their renewal.

This article summarizes the results of long-term integrated research performed by the Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences (SIPPВ SB RAS), to study the composition, structure, and dynamics of biodiversity in Siberia and adjacent regions at the level of populations, species, biocoenoses, and ecosystems and reveal the responses of organisms and their coenoses to changes in environmental conditions caused by natural and anthropogenic factors. The sequestration of carbon dioxide by conifer forests growing on the territory of Baikal Natural Region (BNR) is estimated. Forest fires in Transbaikalia are reconstructed on the basis of tree-ring chronology with an annual resolution of 351 years. The concept of paragenesis is justified, as it characterizes the formation of phytocoenoses that, in regards to their structural–dynamic organization, are not related to a zonal type (or altitudinal belt) of vegetation. The data can serve as an information base while determining basic vectors of regional ecological policy, and they are important for assessing the present state of biodiversity in Baikal Siberia and its changes under the conditions of anthropogenic pressure, as well as for developing measures for its protection.

We have established concentrations of 32 elements (Ag, Al, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Sr, Ti, V, W, Y, Zn) in the thalloms of the terrestrial algae Nostoc commune from the Baikal region, functioning in the meadow steppe on sod-carbonate soil. Nostoc commune is a widespread species in terrestrial ecosystems, capable of oxygenic photosynthesis and fixation of atmospheric nitrogen. The concentrations of elements in the Nostoc commune from the Baikal region according to the degree of reduction are presented in the following series: Al > Ca > Mg > K > Fe > P > S > Ti > Na > Ba > Sr > Mn > Cr > Zn > V > Li > Ni > Ce > Cu > La > Bi > Sb > W >Y > Pb > Sc > Co > As > Mo > Ag > Be > Cd. High correlations between the content of Ca, Mg, K in the soil and thalloms of the species were revealed.

Filamentous green chaetophoralean algae are distributed mainly in aquatic ecosystems, less known from terrestrial habitats. Many of them have a complicated thalli and complex life cycles that make it difficult to determine these organisms by morphology. Description of new representatives of the Chaetophorales continues. In this study, we have explored the filamentous green alga IRK–A 341 from soil of the Baikal Region by light and electron microscopy along with molecular phylogeny. Based on the results of morphological, ecological, and molecular phylogenetic analyses (18S–28S rDNA, tufA), we described the studied alga as the new species, Barranca variabilis sp. nov. The study complements the data on the diversity of soils green filamentous algae, and their biogeography. For the first time, the data on the structure of the cell walls and the cell ultrastructure of Barranca were established. The information on the morphology of the reproductive and resting cells is updated.

We describe the morphological features and the phylogenetic relationships of five morphologically similar strains belonging to the genus Coelastrella, which live in different ecological and geographical conditions of terrestrial ecosystems: in the Ural Mountains (Polar, Subpolar, and Northern Urals of Russia) and the Khentii Mountains (Russia and Mongolia). We analysed algal strains stored in the Culture Collection of Algae of the Institute of Biology, Syktyvkar, Russia (SYKOA Ch-045-09, SYKOA Ch-047-11, SYKOA Ch-072-17) and the Culture Collection of Algae at Herbarium of the Siberian Institute of Plant Physiology and Biochemistry, Irkutsk, Russia (IRK-A 2, IRK-A 173). By light microscopy, all samples were assigned to Coelastrella terrestris. However, the phylogenetic analyses based on the nucleotide sequences of 18S rDNA and ITS1-ITS2 showed that only one strain belongs to C. terrestris (IRK-A 173). Other samples were closer to C. oocystiformis (SYKOA Ch-045-09; IRK-A 2) and C. aeroterrestrica (SYKOA Ch-047-11). The strain SYKOA Ch-072-17 is probably a new species for the genus. These results confirmed the high phenotypic variability and the hidden diversity among the members of this green algal group.

Резюме: В представленном обзоре рассматривается роль фототрофов в альтернативной энергетике, при этом основной упор сделан на одноклеточные водоросли. Особое внимание уделено применению фототрофов для генерации электроэнергии с использованием биотопливных элементов (обсуждаются растительные и ферментные биотопливные элементы). Главное место отведено микробным топливным элементам (МТЭ), которые наряду с электроэнергией позволяют получать биотопливо и биоводород. Рассматриваются факторы, ограничивающие мощность МТЭ, а также пути их преодоления. Так, например, для снижения убыли мощности МТЭ из-за перенапряжения представляется перспективной разработка различных фотобиореакторов. Использование микрофототрофов в МТЭ привело к разработке фотосинтетических МТЭ (или ФотоМТЭ) посредством конструирования автотрофных фотобиореакторов с принудительным освещением. Они дают возможность генерировать кислород за счет фотосинтеза как in situ, так и ex situ, рециркулируя кислород из фотобиореактора в катодную камеру. Здесь могут быть использованы искусственные редокс-медиаторы, переносящие электроны непосредственно с некаталитического катода на O2, образующийся в результате фотосинтезирующей активности водорослей. Показано, что биологически катализируемые катоды генерируют меньшую мощность по сравнению с химическими катализаторами. Отмечено, что установки МТЭ с микроводорослями позволяют утилизировать широкий круг различных соединений – компонентов сточных вод и отходов: органические кислоты, сахара, спирты, жиры и другие субстраты. Особый раздел представляет использование фототрофов для производства биотоплива. Из микроводорослей можно получить несколько различных видов возобновляемого биотоплива, производство которого может быть объединено с очисткой сточных вод, улавливанием CO2, производством различных соединений.

Five strains of the genus Coelastrella were studied from the collections of live cultures of algae of the Institute of Biology, Syktyvkar, Russia (SYKOA Ch-045-09, SYKOA Ch-047-11, SYKOA Ch-072-17) and the Siberian Institute of Plant Physiology and Biochemistry, Irkutsk, Russia (IRK-A 2, IRK-A 173). It was found that, despite their high morphological similarity, the strains have different phylogenetic relationships. The analysis of the 18S rDNA and ITS1-ITS2 showed that the studied strains belong to the species: C. terrestris (IRK-A 173), C. oocystiformis (SYKOA Ch-045-09; IRK-A 2) and C. aeroterrestrica (SYKOA Ch-047-11). The SYKOA Ch-072-17 strain is probably a new species for the genus. The results confirm the high phenotypic variability and hidden diversity among the representatives of this group of green algae.