The genus Klebsormidium is a cosmopolitan filamentous alga that belongs to the phylum Charophyta and inhabits a wide range of environments, primarily freshwater, soil, and aerial habitats. Its basal position on the Streptophyta phylogenetic tree, widespread distribution and significant functional role make the genus Klebsormidium an important object for phycological research. To advance the molecular phylogeny of Klebsormidium , we conducted the first comparative evaluation of six species delimitation methods – ASAP (Assemble Species by Automatic Partitioning), LocMin (Local Minima), KoT (K over Theta), GMYC (Generalized mixed Yule-coalescent), mlPTP (Poisson Tree Process with Maximum Likelihood), and bPTP (Poisson Tree Process with Bayesian inference) – using rbc L and concatenated ITS2– rbc L fragments. The accuracy of these methods was further validated against molecular, morphological, and ecological data. According to an integrative approach, Klebsormidium mirabile sp. nov. was proposed as a new charophyte species from soil of the Fergana Valley, Uzbekistan. In addition, a study on the fatty acid composition showed that the authentic strain VKM Al-436 of this new species of Klebsormidium is a potential source of polyunsaturated fatty acids, including linoleic, α-linolenic, and hexadecatrienoic acids.

The effectiveness of cryopreservation of cyanobacteria and eukaryotic microalgae from various taxonomic groups, including charophytes, chlorophytes, and heterokontophytes, was evaluated for 24 strains from the funds of the All-Russian Collection of Microorganisms (VKM). This comparative study was conducted on the cultures of microalgae that differ in cellular size, morphological organization of the thallus, method of reproduction, presence and size of mucilage envelopes, and the ability to form dormant cells. Two variants of cryoprotective agents (methanol and dimethyl sulfoxide), two types of nutrient media (slant agar and liquid medium), as well as three methods for determining the post-cryopreservation survival rates of microalgae were tested. A two-stage cryopreservation protocol that employed both cryoprotective agents (methanol and dimethyl sulfoxide) was successfully applied to all 24 strains studied, regardless of their taxonomic affiliation and morphological characteristics. Based on the obtained results, we developed a standard procedure for cryopreservation of microalgae and cyanobacteria that included a liquid culture medium with dimethyl sulfoxide, as well as two methods for determining the survival of organisms after cryopreservation, growth in a liquid medium and streaks on agar. The proposed protocol ensures not only the preservation of cell viability and the possibility of further use of a strain as a morphologically and genetically representative sample, but also minimizes the time and resource costs, as well as the risk of culture contamination.

Представлена новая концепция биоремедиации антропогенных водных объектов, а также очистки сточных карьерных вод методом фитоэкстракции и фитотрансформации в арктических условиях, основанная на технологии преобразования техногенных водоёмов в природоподобные болотные экосистемы. Технология базируется на создании фитоматов, позволяющих в ускоренном режиме формировать растительные блоки трёх разных типов: для задернения песчано-гравийных участков (откосы фильтрационных дамб и др.), для создания растительных сообществ на мелководных участках водоёмов и для создания сообществ на глубоководных участках. При формировании фитоматов используются два субстрата-почвозаменителя и регионально-оптимизированный ассортимент из 24 видов растений. Определение содержания нитрат-ионов в некоторых растениях биоплато (Comarumpalustre L., Eryophorum angus-tifolium Honck., Salixphylicifolia L.) показало их преимущественное накопление в корнях. Предлагаемый подход к формированию природоподобных болотных экосистем для очистки сточных карьерных вод впервые осуществлён в практике действующих горнорудных предприятий в экстремальных условиях Субарктики. Внедрение данной технологии позволило на 22% повысить эффективность очистки сточных карьерных вод от минеральных соединений азота, не требуя при этом затрат энергии, химикатов и дефицитных в регионе почвенных...

The results of morphological and phylogenetic analysis of Coleochlamys apoda strain ACSSI 377, isolated from the biological soil crust on the surface of a sandy substrate in the North of Russia (Murmansk region) are presented. Morphology is described, including the presence of mature S-shaped cells typical of the species С. oleifera, and formation of synzoospores was reported for the first time for the species. Analysis of the 18S rRNA and rbcL gene sequences indicated that the strain belonged to the species Coleochlamys apoda (order Microthamniales); this is the first finding of this species found in the Russian territory confirmed by molecular genetic techniques. The presence of clades consisting of uncultured clones on the 18S rRNA gene tree was an indication of the order being insufficiently studied and of the prospects of detection and description of its new members. Ecology and distribution of Coleochlamys and of the sister genus Microthamnion were analyzed based on the literature date and the authors’ observations. Members of the genus Coleochlamys prefer cold habitats and occur within a limited geographic range, in contrast to Microthamnion, which has been repeatedly found in various regions.

This study presents a screening of microalgae strains for their resistance to heavy metals, specifically copper. Various species of green algae and cyanobacteria were examined, identifying strains with increased tolerance to metal contamination. Results indicate that at copper concentrations above 3 mg/L, growth is completely inhibited, while Nostoc sp. LK-20-1 exhibits survival and adaptation capabilities. The study also explored the physiological effects of copper exposure on microalgal morphology. In strains exposed to high copper levels (3 mg/L and above), significant changes were observed, including reduced cell size and the breakdown of chlorophyll pigments. Interestingly, Nostoc sp. LK-20-1 continued to form biomass in high copper environments, even though the cells exhibited minor pigmentation defects. This strain was further tested for its ability to grow across a range of copper concentrations (from 10 µg/L to 2 mg/L), revealing consistent growth at lower concentrations and partial recovery at higher levels. This strain shows potential for bioremediation of contaminated areas, offering prospects for environmentally safe decontamination technologies.