The Journal of V.N.Karazin Kharkiv National University. Series «Biology»

Molecular identification of four Dunaliella strains from Ukraine via ITS2 marker

2026-06-01T19:54:18+00:00

Species of the genus Dunaliella are model organisms in algal physiology and widely used in phycotechnologies for commercial production of bioactive compounds, particularly carotenoids (mainly β-carotene). Reliable species identification is challenging due to low morphological variability and the absence of distinct species-specific traits in Dunaliella. Common traits such as cell size, shape, and pigmentation are strongly influenced by environmental factors, often leading to misidentification in culture collections and complicating comparative and applied research. Molecular approaches have thus become essential for accurate species identification. However, molecular data on Dunaliella from Ukraine remain scarce. The internal transcribed spacer 2 (ITS2) region is particularly informative, combining conserved secondary structures with rapidly evolving primary sequences. This study performed molecular identification of four Dunaliella strains from the Cherniaev Herbarium MicroAlgae Culture Collection (CWU-MACC), V.N. Karazin Kharkiv National University, using the ITS2 marker. Species identification was performed based on sequence similarity and phylogenetic analysis. Among the four Ukrainian strains, only CWU-MACC-15 corresponded to D. salina, while the others, including CWU-MACC-16, previously identified as D. salina, were assigned to D. viridis. The ITS2 sequences of CWU-MACC-16 and CWU-MACC-20 were identical, whereas the Henichesk Lake isolate showed a minor ITS2 variation within D. viridis. These results provide a molecular basis for the taxonomy of Dunaliella strains from Ukraine and highlight the need for expanded sampling and additional molecular markers to further resolve species diversity and phylogenetic relationships.

First record of Mordellistena multicicatrix Kangas, 1986 (Coleoptera, Mordellidae) in Ukraine: morphological and ecological analysis

2026-06-01T19:55:17+00:00

Mordellistena multicicatrix Kangas, 1986 is recorded for the fauna of Ukraine for the first time. Therefore, currently in Ukraine there are 4 species of tumbling flower beetles from the pentas species group (proposed by K. Ermisch in 1956): M. secreta Horák, 1983, M. pentas Mulsant, 1856, M. dalmatica Ermisch, 1956 and M. multicicatrix. The pupa of M. multicicatrix was found in the pith of the stem of annual fleabane (Erigeron annuus (L.) Desf.) in Chernihiv in 2018. The hatched male was kept in laboratory conditions were it fed on pollen of the common dandelion (Taraxacum officinale F. H. Wigg.). A comprehensive analysis of the obtained data was carried out. The morphological characteristics of M. multicicatrix adults were analyzed and certain ecological characteristics of this species were identified. Until now, the detailed morphology of the M. multicicatrix adult was known only from the species description, which was based on a single male (holotype). Thus, the results of the morphological analysis can be used to take into account the variability of M. multicicatrix when identifying this species of tumbling flower beetles. The article presents the measurement results of the most variable morphological features of M. multicicatrix. Photographs of its habitus and parameres are provided for the first time. It is shown that the ratio of the length of antennomeres 5–10 to their width cannot be used as a feature that would reliably distinguish males of M. multicicatrix from M. secreta. The absence of external signs of suppression of the plant in which the pupa was found can be explained by the fact that during the development of the M. multicicatrix larva, the vascular bundles in the stem remain intact. Based on the analysis of the length of the larval tunnel, which was made by the found specimen when it was at the larval stage, it is shown that M. multicicatrix can lay eggs in the upper third of a stem. The length and diameter of the analyzed larval tunnel indicate the impossibility of the development of two or more M. multicicatrix larvae in one stem. Given the climatic conditions in the Chernihiv region, the find of the M. multicicatrix pupa at the end of April indicates that the development of the larva that preceded it began in June 2017. By the beginning of winter diapause, the larva had reached the last larval instar. Potential threats to M. multicicatrix were identified.

From Malthusian trap to demographic transition: educational and research aspects of a university simulation course

2026-06-01T14:54:56+00:00

This article describes a simulation model developed through a collaborative effort between Master’s students, PhD students, and lecturers within the course “Simulation Modelling of Stability and Evolution of Supraorganismal Biosystems”. Over a series of academic sessions in the R environment, the “Humanity Growth” simulation model was developed, which features a step-by-step increase in systemic complexity. This model belongs to the category "mechanism-sufficiency models" (models that test whether a proposed mechanism is sufficient to reproduce observed dynamics). The baseline architecture consists of an exponential population growth model with several age classes, each characterized by its own birth and death rates. In subsequent stages, the model sequentially integrates: a logistic constraint on carrying capacity (Verhulst parameter); the effect of a time lag in the population's response to resource scarcity (Nicholson parameter); a reduction in environmental capacity resulting from overpopulation crises (Easter Island parameter); the expansion of carrying capacity driven by lifestyle-improving cultural evolution (von Foerster parameter); and, finally, the mechanism of demographic transition (Notestein parameter). The paper discusses the model's structure, simulation results, and alternative algorithmic solutions considered during collaborative development. The authors consider this step-by-step modelling approach successful and offer their experience for its further development and application.

Effect of aqueous extracts from natural sweetener-producing plants on the growth and antagonistic and phytotoxic activity of soil microorganisms

2026-06-01T14:55:42+00:00

This study assessed the effect of aqueous extracts from natural sweetener-producing plants — Stevia rebaudiana (stevia) leaves, Glycyrrhiza glabra (licorice) roots/rhizomes, and Helianthus tuberosus (Jerusalem artichoke) tubers — on the growth, antagonistic, and phytotoxic activities of soil microorganisms, including several bacterial species, micromycetes, and the green alga Tetracystis sp. The addition of aqueous extracts to the nutrient medium stimulated colony growth in all tested micromycetes and the bacterium Azotobacter chroococcum. The highest stimulatory effect was observed for extracts from stevia leaves and Jerusalem artichoke tubers. The antagonistic activity of the micromycete Trichoderma viride against potentially phytopathogenic fungi was enhanced during co-cultivation with aqueous extracts from all studied plants. The strongest phytotoxic effect was exerted by Aspergillus niger when grown on a medium supplemented with licorice root extract. Conversely, the lowest level of phytotoxicity was observed for Fusarium oxysporum cultivated with the addition of Jerusalem artichoke tuber extract. These findings indicate the selective and species-specific influence of aqueous extracts of the studied plants on the functional activity of the soil microbiome. This effect could be leveraged to develop biological agents aimed at optimizing cultivation conditions for natural sweetener-producing crops.

The phenomenon of Oleg Spivakov — taxidermist, artist, and museologist

2026-06-02T07:54:01+00:00

Oleg Spivakov is one of the most notable Ukrainian taxidermists of the late 20th and early 21st centuries, an artist, and a museum professional. Based on biographical data and an analysis of museum collections, this text highlights the formation of his unique signature style, which combines scientific accuracy with high artistic craftsmanship. A graduate of Taurida University, Oleg dedicated his life to the development of natural history museums: first, to the restoration the Museum of Nature and History of Karadag at the Karadag biostation (1982–2008), and later, to Zoological Museum of Taras Shevchenko National University in Kyiv (2009–2021). The master was virtuoso in the techniques of creating taxidermy sculptures across diverse taxonomic groups—from fish and amphibians to birds and mammals—and his works now grace countless state and private collections. The "Crimean period" of Oleg Spivakov’s career is analysed in detail, the key achievement of which was the revival of the Museum of Nature and History of Karadag. (In fact, it was a creation "from scratch," as no exhibits from the old collection remained). The article describes his innovative approach to building the exhibition according to the biotopic principle, where the author created over 400 specimens covering about 200 species of vertebrates. Furthermore, Oleg Spivakov made a significant contribution to the study of the Crimean fauna, particularly through the records of rare bird and mammal species that have entered scientific circulation. Special attention is paid to the ‘Kyiv period’, marked by the creation of taxidermy sculptures of fish, amphibians, and mammals. His role in the restoration of old collection specimens in the exhibition of the Zoological Museum of Kyiv University (ZMKU) is also characterised. Oleg Spivakov’s creative heritage in taxidermy represents a significant contribution to national museology, particularly in the formation and restoration of zoological exhibitions. His legacy is not limited to museum halls: the master’s works constitute a significant part of numerous private collections, where they are valued as unique pieces of art. The master’s works are distinguished by an exceptionally high artistic level, which effectively grants them the status of works of art.

Ornithological collections from the time of the First and Second World Wars at the National Museum of Natural History, National Academy of Sciences of Ukraine

2026-06-01T14:57:31+00:00

This study investigates the formation, preservation, and transformation of the ornithological collection of the National Museum of Natural History of the National Academy of Sciences of Ukraine (NMNH) during the First (1914–1918) and Second (1939–1945) World Wars. Based on the analysis of historical sources, inventory books, collection catalogues, and specimen labels, the pathways of accession were reconstructed, the specific features of scientific activity under conditions of social upheaval were identified, and the scientific, cultural, and conservation value of the materials was assessed. The object of the study was the ornithological collection of the NMNH, which comprises more than 40 000 storage units, including study-skins, egg clutches, and exhibited skin-mounts. More than 700 specimens collected during wartime were examined, with detailed breakdowns by year, region, collector, and taxonomic composition. Particular attention was paid to Kyiv Oblast—the only region represented in the collections by a sufficient number of specimens from both wartime periods. In 1919–1933, despite the absence of the museum as an institution, the collections were enriched mainly through donations of private collections and materials from other institutions; more than 89% of specimens originated from Kyiv Oblast and the Crimea. Specimens of 15 species currently listed in the Red Data Book of Ukraine were identified: Anarhynchus alexandrinus (3), Falco naumanni (2), Milvus migrans (2), Grus virgo (1), Asio flammeus (1), Bubo bubo (1), Circus macrourus (1), Glareola nordmanni (1), Haematopus ostralegus (1), Lanius excubitor (1), Podiceps grisegena (1), Recurvirostra avosetta (1), Pastor roseus (1), Tetrao urogallus (1), and Tetrastes bonasia (1). During the Second World War, museum activity was uneven: the peak of collections occurred in 1939–1940, followed by a sharp decline. In total, the collections were enriched with 364 specimens, of which 257 originated from Ukraine, mainly from Kyiv Oblast. Among these gatherings, specimens of 17 species listed in the Red Data Book of Ukraine were identified: Numenius arquata (3), Picus viridis (3), Circus cyaneus (2), Grus virgo (1), Clanga clanga (1), Bucephala clangula (1), Alaudala rufescens (1), Dendrocopos leucotos (1), Haematopus ostralegus (1), Limosa limosa (1), Milvus migrans (1), Netta rufina (1), Recurvirostra avosetta (1), Branta ruficollis (1), Sternula albifrons (1), Strix uralensis (1), and Tringa stagnatilis (1).

The effectiveness of artificial pollination in various representatives of the genus Pisum L.

2026-06-01T14:58:04+00:00

Wild relatives of cultivated pea (Pisum sativum L.) represent an important reservoir of alleles associated with resistance to biotic and abiotic stressors; however, their use in breeding programs is constrained by limited knowledge of their diversity and by difficulties in obtaining hybrids under field conditions. In this study, we evaluated the efficiency of interspecific hybridization among P. sativum, P. elatius and P. fulvum under field conditions, focusing on the effects of flower emasculation timing, parental genotype, and direction of the cross. Morphological characteristics of the parental accessions were used to facilitate hybrid identification based on seed-coat coloration in direct and reciprocal crosses. Two pollination approaches were compared: immediate pollination following flower emasculation and delayed pollination conducted 24 hours after emasculation.

Across combinations involving P. sativum, hybrid seed set (S/F index) was consistently higher when pollination was performed immediately after emasculation. Delayed pollination resulted in a marked reduction of hybrid seed production, likely reflecting both physiological constraints and high temperature stress during flowering. Reciprocal crosses revealed low and relatively uniform hybridization efficiency in combinations with P. fulvum, whereas crosses involving P. elatius produced substantially higher seed set, consistent with its close genetic affinity to P. sativum. The stability of hybridization efficiency across years (2020 – 2021) was confirmed for several cross combinations. Evaluation of the F₁ and F₂ seed lots demonstrated the successful production of true interspecific hybrids, with diagnostic segregation observed in combinations where the wild species served as the maternal parent.

These results confirm that viable hybrids among representatives of the genus Pisum can be reliably obtained under field conditions and highlight that immediate post- emasculation pollination is the most effective strategy for maximizing hybrid seed production. The findings support the broader use of wild Pisum germplasm in pre-breeding and genetic research and provide practical recommendations for improving interspecific hybridization success in breeding programs.

Spectral characteristics of flowers of the ornamental species Ptelea trifoliata L.

2026-06-01T14:58:32+00:00

One of the directions of flora adventitization is considered to be the spread of naturalized alien ornamental plants outside the territory of introduction in botanical gardens. The problem has become particularly relevant in modern conditions, since climate change may reduce the barriers to naturalization for some ornamental alien species. In this regard, the identification of such species and the study of their functional characteristics are important for predicting future phytoinvasions. Among these species, the common hoptree Ptelea trifoliata L. (family Rutaceae) - an introducer of North American origin - attracts attention. Plants of this species are ornamental shrubs or small trees, characterized by high decorativeness, original crown structure, bright color of leaves and flowers with a unique aroma. Extracts from different parts of the plant exhibit biological activity, which confirms the prospect of further pharmacognostic studies of this species. However, the pigment composition and spectral indicators of flowers for the identification of common hoptree have not yet been studied. The reflective and colorimetric characteristics of P. trifoliata petals were determined for the first time. The presence of flavonoids, carotenoids, and chlorophylls in vivo was confirmed by the position of analytical maxima and the ratios of their intensities in the reflection spectrum. The use of first-order differentiation of the spectral curve increased the degree of separation of the maxima of light-absorbing compounds localized in the surface tissues of the petals. As a result of the analysis of the spectral distribution of the light flux reflected from the pigmented surface, colorimetric parameters were obtained. The combination of these parameters determines the color stimulus, which defines the corresponding perception of the color of the studied flowers by the observer. The results obtained can be used to identify the color feature of common hoptree flowers, as well as to confirm the identity of the raw materials of this plant when obtaining biologically active substances.