Miroslava Konstantinova Zhiponova

@uni-sofia.bg

Department of Plant Physiology/Faculty of Biology
Sofia University



                    

https://researchid.co/zhiponova
32

Scopus Publications

1350

Scholar Citations

11

Scholar h-index

16

Scholar i10-index

Scopus Publications

  • Functional Genomics of Legumes in Bulgaria—Advances and Future Perspectives
    Miglena Revalska, Mariana Radkova, Miroslava Zhiponova, Valya Vassileva, and Anelia Iantcheva
    MDPI AG
    Members of the Leguminosae family are important crops that provide food, animal feed and vegetable oils. Legumes make a substantial contribution to sustainable agriculture and the nitrogen cycle through their unique ability to fix atmospheric nitrogen in agricultural ecosystems. Over the past three decades, Medicago truncatula and Lotus japonicus have emerged as model plants for genomic and physiological research in legumes. The advancement of innovative molecular and genetic tools, particularly insertional mutagenesis using the retrotransposon Tnt1, has facilitated the development of extensive mutant collections and enabled precise gene tagging in plants for the identification of key symbiotic and developmental genes. Building on these resources, twelve years ago, our research team initiated the establishment of a platform for functional genomic studies of legumes in Bulgaria. In the framework of this initiative, we conducted systematic sequencing of selected mutant lines and identified genes involved in plant growth and development for detailed functional characterization. This review summarizes our findings on the functions of selected genes involved in the growth and development of the model species, discusses the molecular mechanisms underlying important developmental processes and examines the potential for the translation of this fundamental knowledge to improve commercially important legume crops in Bulgaria and globally.

  • Chemotaxonomy and Bioactive Potential of High-Mountain Plantago atrata
    Miroslava Zhiponova, Zhenya Yordanova, Georgi Ivanov, Uroš Gašić, Danijela Mišić, Kalina Alipieva, Desislava Mantovska, Ginka Cholakova, Alexandra Kapogianni, Ivanka Tsacheva,et al.
    Wiley
    ABSTRACTPlantago atrata Hoppe is a high‐altitude mountain plant exposed to harsh environmental factors. This study aims to elucidate the ecological, phytochemical and pharmacological characteristics of this lesser‐known plantain. Despite nutrient‐poor peat soil, the leaves of P. atrata contained increased levels of phosphorus, potassium and calcium, and the anatomy revealed an isobilateral mesophyll. Molecular taxonomic identification and phylogenetic analyses confirmed the classification of the studied plant as P. atrata and its clustering with narrow‐leaved plantains growing in extreme conditions. Detailed phytochemical profiles revealed primary and secondary metabolites that can be used as taxonomic identifiers and for bioactivity studies. The methanol fraction enriched in phenolic compounds appeared biologically active—by displaying limited antimicrobial activity, however, it possessed significant radical‐scavenging and anti‐inflammatory capacity. The data demonstrate that P. atrata’s leaf parameters and phytochemical arsenal assure plant survival and reveal the plantain's pharmaceutical potential in inhibiting inflammation via the classical pathway of Complement activation.

  • Modulation of Zn Ion Toxicity in Pisum sativum L. by Phycoremediation
    Zornitsa Karcheva, Zhaneta Georgieva, Svetoslav Anev, Detelina Petrova, Momchil Paunov, Miroslava Zhiponova, and Ganka Chaneva
    MDPI AG
    Microalgae offer a promising alternative for heavy metal removal, and the search for highly efficient strains is ongoing. This study investigated the potential of two microalgae, Coelastrella sp. BGV (Chlorophyta) and Arthronema africanum Schwabe & Simonsen (Cyanoprokaryota), to bind zinc ions (Zn2⁺) and protect higher plants. Hydroponically grown pea (Pisum sativum L.) seedlings were subjected to ZnSO4 treatment for 7 days in either a nutrient medium (Knop) or a microalgal suspension. The effects of increasing Zn2⁺ concentrations were evaluated through solution parameters, microalgal dry weight, pea growth (height, biomass), and physiological parameters, including leaf gas exchange, chlorophyll content, and normalized difference vegetation index (NDVI). Zinc accumulation in microalgal and plant biomass was also analyzed. The results revealed that microalgae increased pH and oxygen levels in the hydroponic medium while enhancing Zn accumulation in pea roots. At low ZnSO4 concentrations (2–5 mM), microalgal suspensions stimulated pea growth and photosynthetic performance. However, higher ZnSO4 levels (10–15 mM) caused Zn accumulation, leading to nutrient deficiencies and growth suppression in microalgae, which ultimately led to physiological disturbances in peas. Coelastrella sp. BGV exhibited greater tolerance to Zn stress and provided a stronger protective effect when co-cultivated with peas, highlighting its potential for phycoremediation applications.

  • In Vitro Anticancer Effects of Aqueous Leaf Extract from Nepeta nuda L. ssp. nuda
    Zlatina Gospodinova, Georgi Antov, Svetozar Stoichev, and Miroslava Zhiponova
    MDPI AG
    Despite significant efforts, cancer remains the second leading cause of mortality worldwide. The medicinal plant Nepeta nuda L. represents a valuable source of biologically active compounds with pharmacological activities including antioxidant, anti-inflammatory, antimicrobial, and antiviral. This study aimed to assess the antiproliferative potential and mechanisms of action of aqueous extract from the leaves of wild-grown N. nuda. Cancer cell lines, MDA-MB-231, MCF7 (breast), HT29, Colon 26 (colon), and HepG2 (liver cancer), and a non-cancerous skin cell line, BJ, were assessed for antiproliferative activity by MTT assay and observation of cell morphological alterations. The cancer cell line that was most sensitive to the extract was further studied for apoptotic alterations by Annexin V/propidium iodide staining, colony-forming assay, and qRT-PCR analysis. The results revealed that the plant extract inhibited the proliferation of all investigated cancer cell lines with the strongest cytostatic effect on Colon 26 cells with a half maximal inhibitory concentration (IC50) value of 380.2 μg/mL and a selectivity index (SI) of 3.5. The extract significantly inhibited the ability of cells to form colonies, exhibited considerable proapoptotic potential involving the participation of the CASP8 gene, and increased the expression levels of ATG3 and the BECN1 gene, which suggests a role of autophagic cell death in the antitumor action.

  • Pulsed Electric Field Pretreatment Enhances the Enzyme Hydrolysis of Baker’s Yeast
    Ralitsa Veleva, Valentina Ganeva, and Miroslava Zhiponova
    MDPI AG
    Baker’s yeast is a key starting material for producing extracts with diverse compositions and applications. This study investigates the effect of pulsed electric field (PEF) pretreatment, which induces irreversible electropermeabilization, on the enzymatic hydrolysis of yeast. Cell suspensions were exposed to monopolar rectangular pulses in a continuous flow system followed by 4 h of incubation with Alcalase at concentrations of 0.2% and 0.5%. PEF pretreatment significantly improved enzymatic hydrolysis, with maximum intracellular content recovery under electrical conditions resulting in outlet temperatures of 56–58 °C. The released protein reached 163.7 ± 13 mg per gram of dry cell weight (DCW). SDS-PAGE analysis showed that the extracts predominantly contained peptides with molecular masses below 4.7 kDa. The phenolic content was comparable to that of cell lysates obtained after mechanical disruption. The free α-amino nitrogen content and total antioxidant activity reached 218.2 ± 26 mg/gDCW and 53.4 ± 4.6 mg TE/gDCW, respectively, representing 3.2-fold and 2.65-fold increases compared to cell lysates. The hydrolysates from PEF-pretreated cells demonstrated a positive effect on the proliferation of the human keratinocyte cell line HaCat. The obtained data lead to the conclusion that PEF pretreatment is a promising approach to enhance the production of yeast hydrolysates with various applications.

  • Blue Light Enhances the Antioxidant, Antimicrobial, and Antitumor Potential of the Green Microalgae Coelastrella sp. BGV
    Zhaneta Georgieva, Zornitsa Karcheva, Tanya Toshkova-Yotova, Ani Georgieva, Reneta Toshkova, Detelina Petrova, Miroslava Zhiponova, and Ganka Chaneva
    MDPI AG
    Green algae of the genus Coelastrella have attracted the attention of scientists due to their rich biochemical composition and potential for application in phytomedicine. The present study investigated the influence of light on the bioactive capacity of extracts from the Bulgarian strain of the green microalgae Coelastrella sp. BGV. Three LED lights were examined—red/blue (C1), blue (C2), and control white light (C3). The respective ethanol extracts were analyzed for the total content of phenolic antioxidants. The antimicrobial activity was tested using the disk-diffusion method against 10 microorganisms. The antiproliferative and cytotoxic effects on cervical carcinoma HeLa and hepatocellular carcinoma HepG2 cell lines, as well as non-tumorigenic embryonal fibroblasts BALB/3T3 control, were evaluated using a cell viability assay. The overall results highlighted blue light as a factor enhancing the antioxidant, antibacterial, and cytotoxic activities of the C2 microalgal extract. Additionally, the investigated mechanism of the antitumor activity revealed a proapoptotic effect. In contrast, the C1 extract exhibited weaker activity and selectivity, while the C3 extract was the least active but demonstrated high cytotoxic selectivity. This study could contribute to expanding knowledge about the high biological potential of green microalgae and the development of biotechnological approaches for its regulation.

  • Cytokinins enhance the metabolic activity of in vitro-grown catmint (Nepeta nuda L.)
    Miroslava Zhiponova, Zhenya Yordanova, Anna Zaharieva, Lyubomira Ivanova, Uroš Gašić, Danijela Mišić, Neda Aničić, Marijana Skorić, Luka Petrović, Krasimir Rusanov,et al.
    Elsevier BV



  • CHANGES OF GROWTH AND BIOACTIVE POTENTIAL OF THE CYANOPROKARYOTE Arthronema africanum UNDER THE INFLUENCE OF LIGHT


  • Taxonomic fingerprints of Plantago atrata Hoppe - A Review
    G Ivanov, A Kercheva, A Tosheva, Z Yordanova, and M Zhiponova
    IOP Publishing
    Abstract Plantago atrata Hoppe (dark plantain; Plantaginaceae) is a lesser-studied narrow-leaved Plantain species and in the present review, we summarize the knowledge about the plant. The distribution of this alpine species and reported subspecies is described. Emphasis is made on P. atrata taxonomic features including botanical characteristics and phylogenetic discrimination via DNA barcoding and metabolic composition. The ecological significance of this plant species is discussed from floristic and nutrient value points of view. The collected information would serve as a basis for further in-depth research on physiological and phytochemical aspects of P. atrata, which would enable the understanding of this plant’s high-altitude adaptation and its possible contribution to beneficial applications for other organisms.

  • Exploring the Phytochemical Composition and Biological Potential of Balkan Endemic Species Stachys scardica Griseb
    Desislava I. Mantovska, Miroslava K. Zhiponova, Detelina Petrova, Kalina Alipieva, Georgi Bonchev, Irina Boycheva, Yana Evstatieva, Dilyana Nikolova, Ivanka Tsacheva, Svetlana Simova,et al.
    MDPI AG
    Stachys scardica Griseb. is a Balkan endemic species listed in The Red Data Book of Bulgaria with the conservation status “endangered”. Successful micropropagation was achieved on MS medium supplemented with 1.5 mg/L benzyladenine (BA), followed by a subsequent ex vitro adaptation in an experimental field resulting in 92% regenerated plants. Using nuclear magnetic resonance (NMR), phenylethanoid glycosides (verbascoside, leucosceptoside A), phenolic acids (chlorogenic acid), iridoids (allobetonicoside and 8-OAc-harpagide), and alkaloids (trigonelline) were identified, characteristic of plants belonging to the genus Stachys. High antioxidant and radical scavenging activities were observed in both in situ and ex vitro acclimated S. scardica plants, correlating with the reported high concentrations of total phenols and flavonoids in these variants. Ex vitro adapted plants also exhibited a well-defined anti-inflammatory potential, demonstrating high inhibitory activity against the complement system. Employing a disk diffusion method, a 100% inhibition effect was achieved compared to positive antibiotic controls against Staphylococcus epidermidis and Propionibacterium acnes, with moderate activity against Bacillus cereus. The induced in vitro and ex vitro model systems can enable the conservation of S. scardica in nature and offer future opportunities for the targeted biosynthesis of valuable secondary metabolites, with potential applications in the pharmaceutical and cosmetic industries.

  • Uncovering the Interrelation between Metabolite Profiles and Bioactivity of In Vitro- and Wild-Grown Catmint (Nepeta nuda L.)
    Anna Zaharieva, Krasimir Rusanov, Mila Rusanova, Momchil Paunov, Zhenya Yordanova, Desislava Mantovska, Ivanka Tsacheva, Detelina Petrova, Kiril Mishev, Petre I. Dobrev,et al.
    MDPI AG
    Nepeta nuda L. is a medicinal plant enriched with secondary metabolites serving to attract pollinators and deter herbivores. Phenolics and iridoids of N. nuda have been extensively investigated because of their beneficial impacts on human health. This study explores the chemical profiles of in vitro shoots and wild-grown N. nuda plants (flowers and leaves) through metabolomic analysis utilizing gas chromatography and mass spectrometry (GC–MS). Initially, we examined the differences in the volatiles’ composition in in vitro-cultivated shoots comparing them with flowers and leaves from plants growing in natural environment. The characteristic iridoid 4a-α,7-β,7a-α-nepetalactone was highly represented in shoots of in vitro plants and in flowers of plants from nature populations, whereas most of the monoterpenes were abundant in leaves of wild-grown plants. The known in vitro biological activities encompassing antioxidant, antiviral, antibacterial potentials alongside the newly assessed anti-inflammatory effects exhibited consistent associations with the total content of phenolics, reducing sugars, and the identified metabolic profiles in polar (organic acids, amino acids, alcohols, sugars, phenolics) and non-polar (fatty acids, alkanes, sterols) fractions. Phytohormonal levels were also quantified to infer the regulatory pathways governing phytochemical production. The overall dataset highlighted compounds with the potential to contribute to N. nuda bioactivity.

  • Jewel Orchid’s Biology and Physiological Response to Aquaponic Water as a Potential Fertilizer
    Ganka Chaneva, Alexander Tomov, Momchil Paunov, Viktoria Hristova, Valentina Ganeva, Nikolina Mihaylova, Svetoslav Anev, Nikolay Krumov, Zhenya Yordanova, Boris Tsenov,et al.
    MDPI AG
    Ludisia discolor is commonly known as a jewel orchid due to its variegated leaves. Easy maintenance of the orchid allows it to be used as a test system for various fertilizers and nutrient sources, including aquaponic water (AW). First, we applied DNA barcoding to assess the taxonomic identity of this terrestrial orchid and to construct phylogenetic trees. Next, the vegetative organs (leaf, stem, and root) were compared in terms of the level of metabolites (reducing sugars, proteins, anthocyanins, plastid pigments, phenolics, and antioxidant activity) and nutrient elements (carbon, nitrogen, sodium, and potassium), which highlighted the leaves as most functionally active organ. Subsequently, AW was used as a natural source of fish-derived nutrients, and the orchid growth was tested in hydroponics, in irrigated soil, and in an aquaponic system. Plant physiological status was evaluated by analyzing leaf anatomy and measuring chlorophyll content and chlorophyll fluorescence parameters. These results provided evidence of the beneficial effects of AW on the jewel orchid, including increased leaf formation, enhanced chlorophyll content and photosystems’ productivity, and stimulated and prolonged flowering. The information acquired in the present study could be used in addressing additional aspects of the growth and development of the jewel orchid, which is also known for its medicinal value.

  • Catmint (Nepeta nuda L.) Phylogenetics and Metabolic Responses in Variable Growth Conditions
    Detelina Petrova, Uroš Gašić, Lyubomira Yocheva, Anton Hinkov, Zhenya Yordanova, Ganka Chaneva, Desislava Mantovska, Momchil Paunov, Lyubomira Ivanova, Mariya Rogova,et al.
    Frontiers Media SA
    Nepeta nuda (catmint; Lamiaceae) is a perennial medicinal plant with a wide geographic distribution in Europe and Asia. This study first characterized the taxonomic position of N. nuda using DNA barcoding technology. Since medicinal plants are rich in secondary metabolites contributing to their adaptive immune response, we explored the N. nuda metabolic adjustment operating under variable environments. Through comparative analysis of wild-grown and in vitro cultivated plants, we assessed the change in phenolic and iridoid compounds, and the associated immune activities. The wild-grown plants from different Bulgarian locations contained variable amounts of phenolic compounds manifested by a general increase in flowers, as compared to leaves, while a strong reduction was observed in the in vitro plants. A similar trend was noted for the antioxidant and anti-herpesvirus activity of the extracts. The antimicrobial potential, however, was very similar, regardless the growth conditions. Analysis of the N. nuda extracts led to identification of 63 compounds including phenolic acids and derivatives, flavonoids, and iridoids. Quantification of the content of 21 target compounds indicated their general reduction in the extracts from in vitro plants, and only the ferulic acid (FA) was specifically increased. Cultivation of in vitro plants under different light quality and intensity indicated that these variable light conditions altered the content of bioactive compounds, such as aesculin, FA, rosmarinic acid, cirsimaritin, naringenin, rutin, isoquercetin, epideoxyloganic acid, chlorogenic acid. Thus, this study generated novel information on the regulation of N. nuda productivity using light and other cultivation conditions, which could be exploited for biotechnological purposes.

  • Biological Activity and NMR-Fingerprinting of Balkan Endemic Species Stachys thracica Davidov
    Desislava I. Mantovska, Miroslava K. Zhiponova, Milen I. Georgiev, Kalina Alipieva, Ivanka Tsacheva, Svetlana Simova, and Zhenya P. Yordanova
    MDPI AG
    Stachys thracica Davidov is a Balkan endemic species distributed in Bulgaria, Greece, and Turkey. In Bulgaria, it is classified as “rare” and is under the protection of the Bulgarian biodiversity law. The aim of our study was to develop an efficient protocol for ex situ conservation of S. thracica and to perform comparative NMR-based metabolite profiling and bioactivity assays of extracts from in situ grown, in vitro cultivated, and ex vitro acclimated plants. Micropropagation of S. thracica was achieved by in vitro cultivation of mono-nodal segments on basal MS medium. Ex vitro adaptation was accomplished in the experimental field with 83% survival while conserved genetic identity between in vitro and ex vitro plants as shown by the overall sequence-related amplified polymorphism marker patterns was established. Verbascoside, chlorogenic acid, and trigonelline appeared the main secondary metabolites in in situ, in vitro cultivated, and ex vitro acclimated S. thracica. High total phenolic and flavonoid content as well as antioxidant and radical scavenging activity were observed in in situ and ex vitro plants. Further, the anti-inflammatory activity of S. thracica was tested by hemolytic assay and a high inhibition of the complement system was observed. Initiated in vitro and ex vitro cultures offer an effective tool for the management and better exploitation of the Stachys secondary metabolism and the selection of lines with high content of bioactive molecules and nutraceuticals.

  • A common F-box gene regulates the leucine homeostasis of Medicago truncatula and Arabidopsis thaliana
    Anelia Iantcheva, Miroslava Zhiponova, Miglena Revalska, Jefri Heyman, Ivayla Dincheva, Ilian Badjakov, Nathan De Geyter, Irina Boycheva, Sofie Goormachtig, and Lieven De Veylder
    Springer Science and Business Media LLC
    The F-box domain is a conserved structural protein motif that most frequently interacts with the SKP1 protein, the core of the SCFs (SKP1-CULLIN-F-box protein ligase) E3 ubiquitin protein ligases. As part of the SCF complexes, the various F-box proteins recruit substrates for degradation through ubiquitination. In this study, we functionally characterized an F-box gene (MtF-box) identified earlier in a population of Tnt1 retrotransposon-tagged mutants of Medicago truncatula and its Arabidopsis thaliana homolog (AtF-box) using gain- and loss-of-function plants. We highlighted the importance of MtF-box in leaf development of M. truncatula. Protein-protein interaction analyses revealed the 2-isopropylmalate synthase (IPMS) protein as a common interactor partner of MtF-box and AtF-box, being a key enzyme in the biosynthesis pathway of the branched-chain amino acid leucine. For further detailed analysis, we focused on AtF-box and its role during the cell division cycle. Based on this work, we suggest a mechanism for the role of the studied F-box gene in regulation of leucine homeostasis, which is important for growth.

  • Heavy metal stress response of microalgal strains Arthronema africanum and Coelastrella sp. BGV
    Zornitsa Karcheva, Zhaneta Georgieva, Alexander Tomov, Detelina Petrova, Miroslava Zhiponova, Ivanina Vasileva, and Ganka Chaneva
    Pensoft Publishers
    The present study compared the stress response of two microalgal strains – Arthronema africanum (Cyanoprokaryota) and Coelastrella sp. BGV (Chlorophyta), after heavy metals’ treatment. Changes of algal growth, pigment and protein content were analyzed after adding Cu, Cd and Pb (50 µM and 100 µM) to the nutrition medium. It was found that Cd and Pb significantly inhibited growth and protein biosynthesis of microalgae, but the effect of Cu remained less pronounced. In both strains, a decrease of chlorophyll content was observed, while carotenoid content markedly increased, especially in Coelastrella sp. BGV biomass. The addition of 100 µM Cd and 100 µM Pb to the medium caused a strong enhancement of malondialdehyde in both microalgal strains, which corresponded to the significant increase of superoxide dismutase and catalase activity. The antioxidant enzymes appeared to be differently altered by heavy metals’ exposure. The activity of SOD in the Arthronema africanum cells was most strongly affected by Cd, in contrast to Coelastrella sp. BGV that was highly increased by 100 µM Pb. The application of 100 µM Cd and 100 µM Pb increased in a similar manner catalase activity in both microalgae. The strains that were studied showed a high absorption capacity for metal ions, especially for Pb, which was absorbed largely than Cd and Cu. For that reason, we assumed that both microalga and, in particular, Coelastrella sp. BGV, could be successfully used for treatment of contaminated water bodies.

  • In vitro multiplication and NMR fingerprinting of rare veronica caucasica M. Bieb
    Desislava I. Mantovska, Miroslava K. Zhiponova, Milen I. Georgiev, Tsvetinka Grozdanova, Dessislava Gerginova, Kalina Alipieva, Svetlana Simova, Milena Popova, Veneta M. Kapchina-Toteva, and Zhenya P. Yordanova
    MDPI AG
    Micropropagation of rare Veronica caucasica M. Bieb. was achieved by successful in vitro cultivation of mono-nodal segments on MS medium supplemented with 1.0 mg L–1 6-benzylaminopurine (BA) and then transferring the regenerated plants on hormone free basal MS medium for root development. In vitro multiplicated plants were successively acclimated in a growth chamber and a greenhouse with 92% survival. The number of plastid pigments and the total phenolics content in in vitro cultivated and ex vitro adapted plants were unchanged, and no accumulation of reactive oxygen species (ROS) was detected by staining with 3-3′-diaminobenzidine (DAB) and 2′,7′-dichlorofluorescein diacetate (DCF-DA). Nuclear Magnetic Resonance (NMR) fingerprinting allowed for the identification of the major alterations in metabolome of V. caucasica plants during the process of ex situ conservation. Iridoid glucosides such as verproside, aucubin and catalpol were characteristic for in vitro cultivated plants, while in ex vitro acclimated plants phenolic acid–protocatechuic acid and caffeic acid appeared dominant. The successful initiation of in vitro and ex vitro cultures is an alternative biotechnological approach for the preservation of V. caucasica and would allow for further studies of the biosynthetic potential of the species and the selection of lines with a high content of pharmaceutically valuable molecules and nutraceuticals.

  • Review article Short report AtF-box gene expression fine-tunes Arabidopsis thaliana root development
    Miroslava Zhiponova, Jefri Heyman, Lieven De Veylder, and Anelia Iantcheva
    Japanese Society for Root Research

  • Evaluation of the role of Medicago truncatula Zn finger CCHC type protein after heterologous expression in Arabidopsis thaliana
    Mariana Radkova, Miglena Revalska, Miroslava Zhiponova, and Anelia Iantcheva
    Informa UK Limited

  • Extraction of Proteins and Other Intracellular Bioactive Compounds From Baker’s Yeasts by Pulsed Electric Field Treatment
    Valentina Ganeva, Boyana Angelova, Bojidar Galutzov, Vasilij Goltsev, and Miroslava Zhiponova
    Frontiers Media SA
    Yeasts are rich source of proteins, antioxidants, vitamins, and other bioactive compounds. The main drawback in their utilization as valuable ingredients in functional foods and dietary supplements production is the thick, indigestible cell wall, as well as the high nucleic acid content. In this study, we evaluated the feasibility of pulsed electric field (PEF) treatment as an alternative method for extraction of proteins and other bioactive intracellular compounds from yeasts. Baker’s yeast water suspensions with different concentration (12.5–85 g dry cell weight per liter) were treated with monopolar rectangular pulses using a continuous flow system. The PEF energy required to achieve irreversible electropermeabilization was significantly reduced with the increase of the biomass concentration. Upon incubation of the permeabilized cells in water, only relatively small intracellular compounds were released. Release of 90% of the free amino acids and low molecular UV absorbing compounds, 80% of the glutathione, and ∼40% of the total phenol content was achieved about 2 h after pulsation and incubation of the suspensions at room temperature. At these conditions, the macromolecules (proteins and nucleic acids) were retained largely inside. Efficient protein release (∼90% from the total soluble protein) occurred only after dilution and incubation of the permeabilized cells in buffer with pH 8–9. Protein concentrates obtained by ultrafiltration (10 kDa cut off) had lower nucleic acid content (protein/nucleic acid ratio ∼100/4.5) in comparison with cell lysates obtained by mechanical disintegration. The obtained results allowed to conclude that PEF treatment can be used as an efficient alternative approach for production of yeast extracts with different composition, suitable for application in food, cosmetics and pharmaceutical industries.

  • Importance of phenolics in populations of Teucrium chamaedrys (Lamiaceae) from serpentine soils
    Miroslava Zhiponova, Zhenya Yordanova, Dolja Pavlova, Mariya Rogova, Milena Dimitrova, Daniela Dragolova, Elena Tasheva-Terzieva, and Veneta Kapchina-Toteva
    CSIRO Publishing
    The genus Teucrium includes perennial herbs or shrubs widespread all around the world. The wall germander (Teucrium chamaedrys L.) is widely used in traditional and modern medicine for various health disorders and recent research revealed that serpentine populations of this herb have increased antioxidant and respective medical potential compared with calcareous population. The present study aims to elucidate further the role of phenolic compounds for T. chamaedrys growth on serpentine soil. Methanol extracts from two serpentine and two non-serpentine (calcareous and siliceous) Bulgarian populations were obtained and analysed for total quantity of phenolics and flavonoids, and antioxidant activity. The serpentine soils acted as an elicitor of the antioxidant response in T. chamaedrys plants and the increased phenolics level correlated with enhanced antioxidant activity. The calcareous population had lower values but still higher than the siliceous population which had the lowest antioxidant values, although the flavonoid quantity that was equal to the serpentine populations. A gas chromatography-mass spectrometry (GC-MS) assay for identifying phenolic acids pointed to caffeic acid as a dominant compound, with additional cinnamic and benzoic acid derivatives with putative roles as antioxidants, in cell wall lignification for heavy metals chelation, and for interspecies interactions.

  • Overexpression of the NMig1 Gene Encoding a NudC Domain Protein Enhances Root Growth and Abiotic Stress Tolerance in Arabidopsis thaliana
    Valentin Velinov, Irina Vaseva, Grigor Zehirov, Miroslava Zhiponova, Mariana Georgieva, Nick Vangheluwe, Tom Beeckman, and Valya Vassileva
    Frontiers Media SA
    The family of NudC proteins has representatives in all eukaryotes and plays essential evolutionarily conserved roles in many aspects of organismal development and stress response, including nuclear migration, cell division, folding and stabilization of other proteins. This study investigates an undescribed Arabidopsis homolog of the Aspergillus nidulans NudC gene, named NMig1 (for Nuclear Migration 1), which shares high sequence similarity to other plant and mammalian NudC-like genes. Expression of NMig1 was highly upregulated in response to several abiotic stress factors, such as heat shock, drought and high salinity. Constitutive overexpression of NMig1 led to enhanced root growth and lateral root development under optimal and stress conditions. Exposure to abiotic stress resulted in relatively weaker inhibition of root length and branching in NMig1-overexpressing plants, compared to the wild-type Col-0. The expression level of antioxidant enzyme-encoding genes and other stress-associated genes was considerably induced in the transgenic plants. The increased expression of the major antioxidant enzymes and greater antioxidant potential correlated well with the lower levels of reactive oxygen species (ROS) and lower lipid peroxidation. In addition, the overexpression of NMig1 was associated with strong upregulation of genes encoding heat shock proteins and abiotic stress-associated genes. Therefore, our data demonstrate that the NudC homolog NMig1 could be considered as a potentially important target gene for further use, including breeding more resilient crops with improved root architecture under abiotic stress.

  • JIP-test as a tool for early diagnostics of plant growth and flowering uposelected light recipe
    M. ZHIPONOVA, M. PAUNOV, S. ANEV, N. PETROVA, S. KRUMOVA, A. RAYCHEVA, V. GOLTSEV, N. TZVETKOVA, S. TANEVA, K. SAPUNOV,et al.
    Institute of Experimental Botany
    Light is a major factor controlling plant growth and development. To assess the impact of the applied light conditions, we aimed to sort out a tool for early diagnostics of the plant physiological state. We investigated the effect of a blue:red:far-red LED light formula recommended for improved plant performance (flowering). High (BR) and low (BRS) light intensity variants were compared to normal (W) and 'shadowed' (WS) white fluorescent controls. The efficiency of the JIP-test to determine changes during early growth of pea plants was compared to additional physiological characteristics (growth parameters, thermal stability of the thylakoid membranes, chlorophyll content, CO2 assimilation, transpiration). Our data showed the onset of growth inhibition under BR light, while BRS light stimulated plants to reach the flowering stage similarly as the W control. We concluded that the JIP-test is appropriate for early, reliable, and nondestructive analysis of light recipes for plant growth and flowering.

RECENT SCHOLAR PUBLICATIONS

  • Functional Genomics of Legumes in Bulgaria—Advances and Future Perspectives
    M Revalska, M Radkova, M Zhiponova, V Vassileva, A Iantcheva
    Genes 16 (3), 296 2025

  • Chemotaxonomy and Bioactive Potential of High‐Mountain Plantago atrata
    M Zhiponova, Z Yordanova, G Ivanov, U Gašić, D Mišić, K Alipieva, ...
    Chemistry & Biodiversity, e202402433 2025

  • Modulation of Zn Ion Toxicity in Pisum sativum L. by Phycoremediation
    Z Karcheva, Z Georgieva, S Anev, D Petrova, M Paunov, M Zhiponova, ...
    Plants 14 (2), 215 2025

  • Plant-soil interactions and mulching affect the physico-chemical soil parameters and the physiological state of Solanum tuberosum L. and Phaseolus vulgaris L.
    D Danchev, M Paunov, S Anev, AM Nedelcheva, V Vladimirova, ...
    Ecologia Balkanica 16 (2) 2024

  • Pulsed Electric Field Pretreatment Enhances the Enzyme Hydrolysis of Baker’s Yeast
    R Veleva, V Ganeva, M Zhiponova
    Microorganisms 12 (12), 2470 2024

  • In Vitro Anticancer Effects of Aqueous Leaf Extract from Nepeta nuda L. ssp. nuda
    Z Gospodinova, G Antov, S Stoichev, M Zhiponova
    Life 14 (12), 1539 2024

  • Blue Light Enhances the Antioxidant, Antimicrobial, and Antitumor Potential of the Green Microalgae Coelastrella sp. BGV
    Z Georgieva, Z Karcheva, T Toshkova-Yotova, A Georgieva, R Toshkova, ...
    Plants 13 (23), 3295 2024

  • Cytokinins enhance the metabolic activity of in vitro-grown catmint (Nepeta nuda L.)
    M Zhiponova, Z Yordanova, A Zaharieva, L Ivanova, U Gašić, D Mišić, ...
    Plant Physiology and Biochemistry 214, 108884 2024

  • Taxonomic fingerprints of Plantago atrata Hoppe–a Review
    G Ivanov, A Kercheva, A Tosheva, Z Yordanova, M Zhiponova
    IOP Conference Series: Earth and Environmental Science 1305 (1), 012003 2024

  • CHANGES OF GROWTH AND BIOACTIVE POTENTIAL OF THE CYANOPROKARYOTE Arthronema africanum UNDER THE INFLUENCE OF LIGHT.
    Z GEORGIEVA, Z KARCHEVA, D PETROVA, M ZHIPONOVA, ...
    Oxidation Communications 47 (1), 76-87 2024

  • Exploring the Phytochemical Composition and Biological Potential of Balkan Endemic Species Stachys scardica Griseb
    DI Mantovska, MK Zhiponova, D Petrova, K Alipieva, G Bonchev, ...
    Plants 13 (1), 30 2023

  • Uncovering the Interrelation between Metabolite Profiles and Bioactivity of In Vitro- and Wild-Grown Catmint (Nepeta nuda L.)
    A Zaharieva, K Rusanov, M Rusanova, M Paunov, Z Yordanova, ...
    Metabolites 13 (10), 1099 2023

  • Nepeta nuda L. Plant Extract Preserves the Morphology of Red Blood Cells Subjected to Oxidative Stress
    S Petrova, N Mazhdrakova, S Todinova, V Strijkova, M Zhiponova, ...
    Medical Sciences Forum 21 (1), 35 2023

  • Jewel orchid's biology and physiological response to aquaponic water as a potential fertilizer.
    A Tomov, N Krumov, M Zhiponova, Z Yordanova, B Tsenov, M Paunov, ...
     2022

  • Jewel orchid’s biology and physiological response to aquaponic water as a potential fertilizer
    G Chaneva, A Tomov, M Paunov, V Hristova, V Ganeva, N Mihaylova, ...
    Plants 11 (22), 3181 2022

  • Phylogenetic identification of Balkan endemic Stachys species and genomic stability during ex vitro conservation
    D Mantovska, G Bonchev, M Zhiponova, Z Yordanova
    ARPHA Conference Abstracts 5, e89656 2022

  • Catmint (Nepeta nuda L.) phylogenetics defined by nuclear and chloroplast DNA barcodes
    G Bonchev, M Zhiponova, A Tosheva, V Vassileva
    ARPHA Conference Abstracts 5, e87343 2022

  • Catmint (Nepeta nuda L.) Phylogenetics and Metabolic Responses in Variable Growth Conditions
    D Petrova, U Gašić, L Yocheva, A Hinkov, Z Yordanova, G Chaneva, ...
    Frontiers in Plant Science 13, 866777 2022

  • Heavy metal stress response of microalgal strains Arthronema africanum and Coelastrella sp. BGV
    Z Karcheva, Z Georgieva, A Tomov, D Petrova, M Zhiponova, I Vasileva, ...
    BioRisk 17, 83-94 2022

  • Biological Activity and NMR-Fingerprinting of Balkan Endemic Species Stachys thracica Davidov
    DI Mantovska, MK Zhiponova, MI Georgiev, K Alipieva, I Tsacheva, ...
    Metabolites 12 (3), 251 2022

MOST CITED SCHOLAR PUBLICATIONS

  • Brassinosteroids control meristem size by promoting cell cycle progression in Arabidopsis roots
    MP Gonzlez-Garca, J Vilarrasa-Blasi, M Zhiponova, F Divol, ...
    Development 138 (5), 849-859 2011
    Citations: 589

  • SPEECHLESS integrates brassinosteroid and stomata signalling pathways
    GE Gudesblat, J Schneider-Pizoń, C Betti, J Mayerhofer, I Vanhoutte, ...
    Nature cell biology 14 (5), 548-554 2012
    Citations: 341

  • Brassinosteroid production and signaling differentially control cell division and expansion in the leaf
    MK Zhiponova, I Vanhoutte, V Boudolf, C Betti, S Dhondt, F Coppens, ...
    New Phytologist 197 (2), 490-502 2013
    Citations: 207

  • POLAR-guided signalling complex assembly and localization drive asymmetric cell division
    A Houbaert, C Zhang, M Tiwari, K Wang, A de Marcos Serrano, ...
    Nature 563 (7732), 574-578 2018
    Citations: 174

  • Helix–loop–helix/basic helix–loop–helix transcription factor network represses cell elongation in Arabidopsis through an apparent incoherent feed-forward loop
    MK Zhiponova, K Morohashi, I Vanhoutte, K Machemer-Noonan, ...
    Proceedings of the National Academy of Sciences 111 (7), 2824-2829 2014
    Citations: 73

  • Osmotic stress responses of wheat species and cultivars differing in drought tolerance: some interesting genes (advices for gene hunting)
    L Erdei
    Acta Biologica Szegediensis 46 (3-4), 63-65 2002
    Citations: 68

  • Activation of an alfalfa cyclin‐dependent kinase inhibitor by calmodulin‐like domain protein kinase
    A Pettk‐Szandtner, T Mszros, GV Horvth, L Bak, Csords‐Tth, ...
    The Plant Journal 46 (1), 111-123 2006
    Citations: 60

  • Brassinosteroids regulate the thylakoid membrane architecture and the photosystem II function
    S Krumova, M Zhiponova, K Dankov, V Velikova, K Balashev, T Andreeva, ...
    Journal of Photochemistry and Photobiology B: Biology 126, 97-104 2013
    Citations: 41

  • Revealing the reviving secret of the white dead nettle (Lamium album L.)
    ZP Yordanova, MK Zhiponova, ET Iakimova, MA Dimitrova, ...
    Phytochemistry Reviews 13, 375-389 2014
    Citations: 38

  • Extraction of proteins and other intracellular bioactive compounds from baker’s yeasts by pulsed electric field treatment
    V Ganeva, B Angelova, B Galutzov, V Goltsev, M Zhiponova
    Frontiers in Bioengineering and Biotechnology 8, 552335 2020
    Citations: 37

  • Mitosis-Specific Promoter of the Alfalfa Cyclin-Dependent Kinase Gene (Medsa;CDKB2;1) Is Activated by Wounding and Ethylene in a Non-Cell Division
    MK Zhiponova, A Pettk-Szandtner, E Stelkovics, Z Neer, S Bottka, ...
    Plant Physiology 140 (2), 693-703 2006
    Citations: 32

  • Adaptive changes in photosynthetic performance and secondary metabolites during white dead nettle micropropagation
    V Kapchina-Toteva, MA Dimitrova, M Stefanova, D Koleva, K Kostov, ...
    Journal of Plant Physiology 171 (15), 1344-1353 2014
    Citations: 31

  • Tissue culture applications of Artemisia annua L. callus for indirect organogenesis and production phytochemical
    E Zayova, T Nedev, D Petrova, M Zhiponova, V Kapchina, G Chaneva
    Plant Tissue Culture and Biotechnology 30 (1), 97-106 2020
    Citations: 27

  • Establishment of embryogenic potential of economically important Bulgarian alfalfa cultivars (Medicago sativa L.)
    A Barbulova, A Iantcheva, M Zhiponova, M Vlahova, A Atanassov
    Biotechnology & Biotechnological Equipment 16 (1), 55-63 2002
    Citations: 18

  • Effect of N6-benzyladenine and indole-3-butyric acid on photosynthetic apparatus of Orthosiphon stamineus plants grown in vitro
    D Stoyanova-Koleva, M Stefanova, M Zhiponova, V Kapchina-Toteva
    Biologia plantarum 56, 607-612 2012
    Citations: 17

  • Comparative determination of the essential oil composition in Bulgarian endemic plant Achillea thracica Velen. during the process of ex situ conservation
    ZP Yordanova, MA Rogova, MK Zhiponova, MI Georgiev, ...
    Phytochemistry Letters 20, 456-461 2017
    Citations: 16

  • Catmint (Nepeta nuda L.) Phylogenetics and Metabolic Responses in Variable Growth Conditions
    D Petrova, U Gašić, L Yocheva, A Hinkov, Z Yordanova, G Chaneva, ...
    Frontiers in Plant Science 13, 866777 2022
    Citations: 15

  • Overexpression of the NMig1 Gene Encoding a NudC Domain Protein Enhances Root Growth and Abiotic Stress Tolerance in Arabidopsis thaliana
    V Velinov, I Vaseva, G Zehirov, M Zhiponova, M Georgieva, ...
    Frontiers in Plant Science 11, 815 2020
    Citations: 14

  • Comparative approach for the isolation of genes involved in the osmotolerance of wheat
    M Zhiponova, L Szilk, L Erdei, J Gyrgyey, D Dudits
    Acta Biologica Szegediensis 46 (3-4), 49-51 2002
    Citations: 14

  • Acrobacterium-mediated transformation for engineering of herbicide resistance in alfalfa (Medicago sativa L.)
    A Barbulova, A Iancheva, M Zhiponova, M Vlahova, A Atanassov
    Biotechnology and Biotechnological Equipment (Bulgaria) 16 (2) 2002
    Citations: 14