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This study reports the effects of aqueous extracts obtained from three fern species of Bulgarian origin: Asplenium ceterachL., Asplenium scolopendriumL., and Asplenium trichomanesL. on the contractility and bioelectrogenesis of rat gastric smooth muscle tissues. In the concentration range 0.015–0.150 mg/mL the three extracts contracted smooth muscle tissues in a concentration-dependent manner. The contractions caused by A. ceterachL. and A. scolopendriumL. extracts (0.150 mg/mL) were reduced by ketanserin (5 × 10−7and 5 × 10−6mol/L), an antagonist of serotonin 5-HT2 receptor. The contraction evoked by A. trichomanesL. (0.150 mg/mL) was significantly reduced by 1 × 10−6mol/L atropine, an antagonist of muscarinic receptors, and turned into relaxation against the background of 3 × 10−7mol/L galantamine. After combined pretreatment with galantamine and l-arginine (5 × 10−4mol/L), this relaxation become more pronounced. The study demonstrates that constituents of A. ceterachL. and A. scolopendriumL. extracts act as agonists of 5-HT2 receptors and cause contraction by activating serotonergic signaling system. A. trichomanesL.-induced reaction is an additive result of two opposite-in-character effects. The dominant contraction is initiated by inhibition of acetylcholinesterase activity. The relaxation develops with pre-inhibited acetylcholinesterase, it is significantly potentiated by l-arginine, and therefore associated with nitrergic signaling pathway.

ABSTRACTThe biodiversity of genus Carduusin Bulgaria is grossly under-studied with modern methods, which leads to unclear status of species and hampers the assessment of their habitats and conservation status. In this study, we used the variability of internal transcribed spacers (ITS) to investigate the biodiversity of Carduusspecies collected from different floristic regions of Bulgaria. Thirty-three samples were processed. Among the studied species, C. acanthoidesexhibited the highest ITS variability (eight single nucleotide polymorphisms were found). High ITS variability was also found in C. crispusand C. hamulosus, demonstrating that some of the local Carduusspecies possesses unique genetic diversity, which can serve as source for future divergence of new forms and subspecies. For each species, unique nucleotides suitable as molecular taxonomy markers were identified. However, C. nutansand C. thoermeridisplayed completely identical ITS sequences, which is in agreement with all ITS sequences of these species collected elsewhere in the world and deposited in the NCBI database. After careful analyses of both molecular and morphological data, we propose to restore C. nutansand C. thoermerias one species with two subspecies. Namely, Carduus nutanssubsp. nutansand Carduus nutanssubsp. thoermeri. We recommend diameter of capitulum, length of peduncle, width of peduncle and width of bract as diagnostic features of taxonomic significance for distinguishing the two subspecies.

Over the past decade new ecological indices based on phytoplankton and macrophytes were developed as part of the tools for assessment of the ecological status of water bodies. This study demonstrates the applicability of two of them (Assemblage index /Q/ and Algae Group Index /AGI/) for evaluation of water bodies from a lake type L4 as well as their comparability. Assessment of the ecological status of two lake ecosystems was performed in order to ensure successful protection, enhancement and management of lowland and semi-mountain lakes in Bulgaria. Data on the aquatic flora from Golyamo Skalensko Lake and Malko Skalensko Lake over a period of two years were used to assess their ecological status. In addition, the toxic potential of the established dominant cyanoprokaryotic species was also evaluated. Phytoplankton- and macrophyte-based metrics resulted in complementary evaluation of temporary and long-term environmental conditions. Despite the hydraulic connection and proximity between the two lakes, Golyamo Skalensko Lake and Malko Skalensko Lake appear as completely different ecosystems, according to the phytoplankton structure (species composition, number of species, abundance, seasonal succession), macrophytes and ecological status.

Background: Ferns are underestimated as medicinal plants and their use in traditional medicine is limited despite their diversity. Most of the research on their healing properties and phytochemical composition related to their biological activity has been focused on the secondary metabolites synthesized by ferns. Objective: In this study, we aimed to make an in-depth chemical characterization of three ferns widely spread in Bulgaria - Asplenium ceterach L., Asplenium scolopendrium L. and Asplenium trichomanes L. Methods: Micro elemental analysis was carried out using ICP-MS. Standard laboratory methods were used to determine the content of proteins, fats and fatty acids. Chromatographic methods were applied to quantify some secondary metabolites. Two antioxidant methods and two antimicrobial tests were used to evaluate the biological properties of the ferns tested. Results: Micro elemental analysis showed that these ferns could be useful source of zinc and iron. Protein content slightly varied among the species (13.6% - 18.4% of the dried plant weight). Negligible was the variation in oil content (3.1% - 4.0%, dry weight base); oil composition was dominated by saturated fatty acids. Some principal classes secondary metabolites, individual phenolic acids and flavonoids were quantified. The extract obtained from Asplenium ceterach L. demonstrated the highest antioxidant capacity. Fern extracts showed moderate antimicrobial activity against six of the 14 microorganisms tested. Conclusion: The results obtained may reveal new areas of application for ferns and are a solid basis for comparison with the same species growing in other geographical and climatic conditions, which may affect their healing properties.

Magnetically soft, magnetostrictive metallic glass ribbons are used as in-situ remote query viscosity sensors. When immersed in a liquid, changes in the resonant frequency of the ribbon-like sensors are shown to correlate with the square root of the liquid viscosity and density product. An elastic wave model is presented that describes the sensor response as a function of the frictional forces acting upon the sensor surface.