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Abstract We demonstrate a wide distribution and abundance of hybrids between the river species Ranunculus aquatilis, R. fluitans and R. kauffmannii with the still water species R. circinatus (Batrachium, Ranunculaceae) in rivers of two postglacial landscapes of East Europe, i.e., Lithuania and Central European Russia. The Batrachium species and hybrid diversity is higher in the rivers of Lithuania (4 species and 3 hybrids vs. 2 and 1) and represented mainly by western R. aquatilis, R. fluitans and their hybrids whereas in Central European Russia, the East European species R. kauffmannii and its hybrid are the only dominant forms. Hybrids make up about 3/4 of the studied individuals found in 3/4 of the studied river localities in Lithuania and 1/3 of the individuals found in 1/3 of the localities in Central European Russia. Such extensive hybridization in river Batrachium may have arisen due to the specificity of rivers as open-type ecosystems. It may have been intensified by the transformation of river ecosystems by human activities and the postglacial character of the studied landscapes combined with ongoing climate change. Almost all hybrids of R. aquatilis, R. fluitans and R. kauffmannii originated from unidirectional crossings in which R. circinatus acted as a pollen donor. Such crossings could be driven by higher frequency and abundance of R. circinatus populations as well as by some biological mechanisms. Two hybrids, R. circinatus × R. fluitans and R. circinatus × R. kauffmannii, were formally described as R. × redundans and R. × absconditus. We found a hybrid which most likely originated from additional crossing between R. aquatilis and R. circinatus × R. fluitans.

The central part of the Kuril Archipelago (the Russian Far East) remains the least studied due to its poor accessibility. Such insufficient floristic data lead to uncertainties in the floristic subdivision of the Kuril Islands. We aimed to explore the vascular flora of the Simushir island, the largest one among the Middle Kurils. We revealed 24 new species for the flora of Simushir or Middle Kurils in general, including three species (Callitriche anceps, Carex meyeriana, and Ribes nigrum) that are new for the whole Kuril Archipelago. One-third of species new for Simushir are alien. Almost all the rest of the new species are associated with special types of habitats and can be found only after a detailed study of the island. We reported six new aquatic species for the Middle Kurils, refuting the earlier idea of extreme poverty of the Middle Kurils’ aquatic flora. We found no grounds for drawing a floristic border within the Northern and Middle Kurils, as the floristic similarity between Onekotan (oceanic Northern Kurils), continental Northern Kurils, and Simushir has the same magnitude.

Aquatic plant species are often widespread, even across continents. They pose a challenge to species delimitation and taxonomy due to their reduced morphology and high phenotypic plasticity. These difficulties are even more pronounced in the case of interspecific hybridization. We investigate the aquatic plant genus Stuckenia for the first time on a worldwide scale. Expert species determination is aided by sequencing of nuclear ribosomal ITS and 5S-NTS regions and the plastid intergenic spacers rpl20-5’rps12 and trnT–trnL. Nuclear markers are used to infer hybridization, and the maternal origin of hybrids is addressed with plastid markers. Pure species are subjected to phylogenetic analyses. Two main Stuckenia lineages are found: one consists of S. amblyphylla, S. filiformis, S. pamirica, and S. vaginata, the other includes S. pectinata and S. striata. The widespread species S. pectinata, S. filiformis, and S. vaginata show intraspecific genetic variation, which is structured geographically. Many intraspecific hybrids, which are usually fertile, occur between those genotypes. Interspecific hybrids, which are consistently sterile, are detected among all widespread species; some are reported for the first time in several countries and regions. They originated multiple times from reciprocal crosses and reflect the geographical origins of parental genotypes. Intraspecific genetic variation can be higher than interspecific differences between closely related species. Comparison of phenotypic variation in the field and in cultivation with genotypic variation shows that numerous conspicuous forms have been overestimated taxonomically. These are resolved as phenotypes responding to unusual environments, have recurrently evolved adaptations, or represent extreme forms of continuous variation of the recognized species. However, some specific regional lineages, which have evolved from variable species, may be interpreted as early steps of the speciation process. Hybridization has been underestimated in some regions as a source of Stuckenia diversity, and the respective hybrid plants have been misidentified as intraspecific taxa or even as separate species. Many erroneous entries in sequence databases are detected and summarized. This work provides a sound basis for species delimitation and hybrid recognition in this difficult genus.

Flora of the southern Kuril continental islands is extremely diverse due to the complex history of geology and climate, fluctuating connections with other territories in the past, and the habitat diversity of the archipelago. It is likely well-investigated due to the long history of botanical studies, and floristic findings are expected only in taxonomically difficult plant groups. To test this assumption, we carried out a special investigation of the aquatic vascular plants on the Lesser Kuril Ridge (isl. Shikotan, Polonskogo, Yurii, Tanfilieva, Zelyonyi) and isl. Kunashir. In line with our expectations, we revealed nine taxa that have never been reported for the whole Kuril archipelago (including six new for Sakhalin floristic province of Russia: Potamogeton manchuriensis, P. × sparganiifolius, P. × variifolius, P. × vepsicus, Sagittaria aginashi, Sparganium subglobosum); all of them are aquatic ones. We found 24 species that are new for the Lesser Kuril Ridge or the whole Southern Kurils from which only about a half were aquatic. Unexpectedly, we found 53 mainly terrestrial species that are new for the Little Kurils (the Lesser Kuril Ridge with exception of isl. Shikotan), and substantially supplemented floristic lists of each island.

Floristic subdivision of the northern part of the Kuril archipelago (Russian Far East) remains controversial. Such uncertainty in biogeographical subdivision could be caused by insufficient floristic data due to poor accessibility of mainly uninhabited northern Kuril islands. We aimed to explore the flora of the largest uninhabited northern Kuril island Onekotan to clarify its position in floristic subdivision. All the 19 species that we added to the known flora of Onekotan island grow on Paramushir and often on some other northern Kurils. Additionally, we revealed two species (Minuartia rubella and Poa lanata) that are new for the whole Kuril archipelago. Our findings demonstrated that floristic similarity between Onekotan and the both large northern continental Kuril islands (Shumshu and Paramushir) is higher than it was demonstrated before. However, discussion of floristic subdivision of the Northern Kurils is premature unless all the islands are sufficiently studied. Keywords: Biogeographic subdivision, Cluster analysis, Field survey, Kuril islands, Vascular plants

Aquatic Ranunculus (sect. Batrachium) include homophyllous and heterophyllous plants. The development of floating leaves may be induced by genetic mechanisms or/and environmental conditions and this fact complicates the morphologically based identification of species. DNA-based studies provide the opportunity to expand the knowledge of this complicated group. We studied heterophyllous Ranunculus with well-developed capillary and intermediate leaves and visually homophyllous plants with capillary leaves from a single river basin, with the aim to evaluate their genetic polymorphism and taxonomic status—whether the plants with well-developed and weakly expressed intermediate leaves belong to different forms (taxa) or if they just express morphological variation of one or two taxa in a specific, very variable river environment. The studied heterophyllous and homophyllous plants from different rivers showed high genetic differentiation and a low level of genetic diversity within these groups. The molecular analysis did not reveal any inter simple sequence repeat (ISSR) polymorphism associated with the development of intermediate leaves. An analysis of nuclear ribosomal internal transcribed spacers ITS1–2 sequences revealed several ribotypes, which indicated the genetic heterogeneity of studied plants and indirectly confirmed the hybrid origin of some of them. Sterile plants originated from crossing of R. circinatus and R. penicillatus were discovered in the Skroblus River; however, identification of the parental species was impeded by the polymorphism detected. For this reason, cytological studies were performed and allowed confirmation of the hybrid origin of these plants.

Wound-invasive fungal diseases (WIFDs), especially mucormycosis, have emerged as life-threatening infections during recent military combat operations. Many combat-relevant fungal pathogens are refractory to current antifungal therapy. Therefore, animal models of WIFDs are urgently needed to investigate new therapeutic solutions. Our study establishes combat-relevant murine models of wound mucormycosis using Rhizopus arrhizus and Lichtheimia corymbifera, two Mucorales species that cause wound mucormycosis worldwide. These models recapitulate the characteristics of combat-related wounds from explosions, including blast overpressure exposure, full-thickness skin injury, fascial damage, and muscle crush. The independent inoculation of both pathogens caused sustained infections and enlarged wounds. Histopathological analysis confirmed the presence of necrosis and fungal hyphae in the wound bed and adjacent muscle tissue. Semi-quantification of fungal burden by colony-forming units corroborated the infection. Treatment with liposomal amphotericin B, 30 mg/kg, effectively controlled R. arrhizus growth and significantly reduced residual fungal burden in infected wounds (p < 0.001). This study establishes the first combat-relevant murine model of wound mucormycosis, paving the way for developing and evaluating novel antifungal therapies against combat-associated WIFDs.

Mucorales species cause debilitating, life-threatening sinopulmonary diseases in immunocompromised patients and penetrating wounds in trauma victims. Common antifungal agents against mucormycosis have significant toxicity and are often ineffective. To evaluate treatments against mucormycosis, sporangiospores are typically used for in vitro assays and in pre-clinical animal models of pulmonary infections. However, in clinical cases of wound mucormycosis caused by traumatic inoculation, hyphal elements found in soil are likely the form of the inoculated organism. In this study, Galleria mellonella larvae were infected with either sporangiospores or hyphae of Rhizopus arrhizus and Lichtheimia corymbifera. Hyphal infections resulted in greater and more rapid larval lethality than sporangiospores, with an approximate 10–16-fold decrease in LD50 of hyphae for R. arrhizus (p = 0.03) and L. corymbifera (p = 0.001). Liposomal amphotericin B, 10 mg/kg, was ineffective against hyphal infection, while the same dosage was effective against infections produced by sporangiospores. Furthermore, in vitro, antifungal susceptibility studies show that minimum inhibitory concentrations of several antifungal agents against hyphae were higher when compared to those of sporangiospores. These findings support using hyphal elements of Mucorales species for virulence testing and antifungal drug screening in vitro and in G. mellonella for studies of wound mucormycosis.

Explosive devices, either conventional or improvised, are common sources of injuries during combat, civil unrest, and terror attacks, resulting in trauma from exposure to blast. A blast wave (BW), a near-instantaneous rise in pressure followed by a negative pressure, propagates through the body in milliseconds and can affect physiology for days/months after exposure. Epidemiological data show that blast-related casualties result in significantly higher susceptibility to wound infections, suggesting long-lasting immune modulatory effects from blast exposure. The mechanisms involved in BW-induced immune changes are poorly understood. We evaluated the effects of BW on the immune system using an established murine model. Animals were exposed to BWs (using an Advanced Blast Simulator), followed by longitudinally sampling for 14 days. Blood, bone marrow, and spleen were analyzed for changes in the 1) complete blood count (CBC), and 2) composition of bone marrow cells (BMC) and splenocytes, and 3) concentrations of systemic cytokines/chemokines. Our data demonstrate that BW results in transient bone marrow failure and long-term changes in the frequency and profile of progenitor cell populations. Viability progressively decreased in hematopoietic stem cells and pluripotent progenitor cells. Significant decrease of CD4+ T cells in the spleen indicates reduced functionality of adaptive immune system. Dynamic changes in the concentrations of several cytokines and chemokines such as IL-1α and IL-17 occurred potentially contributing to dysregulation of immune response after trauma. This work lays the foundation for identifying the potential mechanisms behind BW’s immunosuppressive effects to inform the recognition of this compromised status is crucial for the development of therapeutic interventions for infections to reduce recovery time of wounded patients injured by explosive devices.

In this article, we study the possibility of gas turbine unit (GTU) monitoring using interferometric fiber optic sensors. We used the Mach–Zehnder interferometer (MZI) scheme, which can be easily implemented and simply installed on the turbine, and also allows us to solve the problem of phase unwrapping conveniently. In this research, the following main steps were carried out: an experimental scheme based on the MZI was assembled, and its sensitive arm was fixed on the GTU under study; data on various operation modes of the GTU was collected; the data were subjected to frequency FFT analysis, based on which the main rotational speeds of the turbine were identified. With FFT analysis, we also demonstrated multiples harmonics, which appear in the case of GTU after operating time, caused by the number of blades. The possibility of GTU monitoring and analysis using a non-invasive compact fiber-optic sensor is demonstrated: spectral analysis is used to detect the rotor speed, as well as the presence or absence of high-order multiple frequencies indicating blade and bearing defects, which are determined by the number of GTU’s blades and rolling bearing used as turbines rotor supports.

Prodrome of paranoid schizophrenia with the episodic type of course (F20.1 and F20.2 according to ICD-10) and the schizoaffective structure of the episode was retrospectively studied. The pronounced and persistent affect, in particular depression in conjunction with hallucinations and/or delusions throughout the whole episode, served as the basis for an episode qualification as the schizoaffective structure. Diagnosis of schizophrenia was confirmed by the extremely low socio-demographic indicators at the time of the manifest episode, by the presence of catatonic or catatono-oneiroid symptoms in more than half of the patients, as well as an incongruence of hallucination plot and/or delusions against the dominant affect. In most cases, the affective symptoms were detected in clinical presentation of a prodrome and significantly more often in the form of depression, in comparison with bipolar and mixed affective disorders. Different clinical manifestations of negative symptoms were revealed in significantly more than half of the patients. The study showed that there is a significant frequency of negative manifestations in conjugation with depression in the prodrome.

Based on the current study, the clinical characteristics of unipolar depression in the clinical picture of schizophrenia with the paroxysmal type of disease course are presented. Given the concomitant depression with phobic symptoms, the following clinical variants are marked: depression with generalized social phobia and/or anthropophobia and depression with generalized pathological body sensations and hypochondriacal phobias. In other words, we are talking about a necessity to allocate a special type of schizophrenia with affective structure episodes and comorbid neurosis-like symptoms. Information on the basic treatment strategy of schizophrenia with depressive structure episodes and comorbid neurosis-like symptoms in everyday psychiatric practice is also provided.