Anna Atanasova Tomova

Dr. Anna Atanasova Tomova

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Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 January 2025 in Molecules
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MTMaria Todorova
Maria Todorova
AKAngelina Delcheva Kosateva
Angelina Delcheva Kosateva
VPVentsislava Yankova Petrova
Ventsislava Yankova Petrova
Bogdan RanguelovBogdan Ranguelov
Bogdan Ranguelov
SVStela Vasileva Atanasova - Vladimirova
Stela Vasileva Atanasova - Vladimirova
PDPavlina Dolashka
Pavlina Dolashka
Many biologically active compounds have been identified in the mucus of the garden snail Cornu aspersum, which are effective in the treatment of several diseases such as cancer, ulcers, wounds, etc. The incorporation of these compounds into the green synthesis of copper nanoparticles (CuONPs-Muc) was demonstrated in our previous study. Based on the synergistic effect of two reducing agents—C. aspersum snail mucus and ascorbic acid (AsA)—on CuSO4.5H2O, which also act as stabilizers of the resulting compound, a new method for the “green” synthesis of CuONPs-Muc is presented. Using two reducing agents has several advantages, such as forming spherical nanoparticles with a diameter of about 150 nm and reducing the formation time of CuONPs-Muc to 3 h. Analyses by ultraviolet–visible spectroscopy (UV-Vis) and Fourier transform infrared spectroscopy (FT-IR) show the formation of CuONPs-Muc, composed of a mixture of copper and copper oxide. This was confirmed by scanning electron microscopy combined with energy-dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD). Another important advantage of CuONPs obtained by the new method with two reducing agents is the stronger inhibitory effect on the bacterial growth of some Gram-positive and Gram-negative bacterial strains, compared to CuONPs-Muc prepared with only one reducing agent, i.e., a fraction of mucus with an MW > 20 kDa.

13 May 2025 in Molecules
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Journal Article
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MTMaria Todorova
Maria Todorova
VPVentsislava Yankova Petrova
Ventsislava Yankova Petrova
Bogdan RanguelovBogdan Ranguelov
Bogdan Ranguelov
GAGeorgi Avdeev
Georgi Avdeev
LVLyudmila Georgieva Velkova
Lyudmila Georgieva Velkova
PDPavlina Dolashka
Pavlina Dolashka
The green synthesis of metal nanoparticles, mediated by extracts from various biological sources, leads to the formation of nanoparticles with unique characteristics and potential biomedical applications. In this study, a fraction of the mucus from the snail Cornu aspersum with MW > 20 kDa was used as a bioreducing and biostabilizing agent to obtain silver nanoparticles (AgNPs) in different pH media (pH 1.5, 3.5, and 7.0). The AgNPs were characterized using UV-visible spectroscopy, SEM, TEM, XRD, and FTIR. The synthesis at pH 1.5 and pH 3.5 in the presence of two reducing agents (i.e., the C. aspersum mucus fraction with MW > 20 kDa and ascorbic acid [AsA]) resulted in the formation of well-formed spherical nanoparticles (NPs) with larger sizes (20–80 nm) than the NPs obtained at pH 7.0 (20–60 nm) in the presence of only one reducing agent. Furthermore, the biosynthesized AgNPs significantly inhibited the growth of medically significant pathogens such as Gram-positive (Bacillus subtilis NBIMCC2353, Bacillus spizizenii ATCC 6633, Staphylococcus aureus ATCC 6538, and Listeria innocua NBIMCC8755) and Gram-negative (Escherichia coli ATCC8739, Salmonella enteitidis NBIMCC8691, Salmonella typhimurium ATCC 14028, Stenotrophomonas maltophilia ATCC 17666) bacteria compared to output mucus.

15 April 2024 in Pharmaceuticals
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PDPavlina Dolashka
Pavlina Dolashka
KMKarina Marinova
Karina Marinova
PPPetar Petrov
Petar Petrov
VPVentsislava Yankova Petrova
Ventsislava Yankova Petrova
Bogdan RanguelovBogdan Ranguelov
Bogdan Ranguelov
ADAleksander Dolashki
Aleksander Dolashki
Several biologically active compounds involved in the green synthesis of silver and gold nanoparticles have been isolated from snail mucus and characterized. This paper presents a successful method for the application of snail mucus from Cornu aspersum as a bioreducing agent of copper sulfate and as a biostabilizer of the copper oxide nanoparticles (CuONPs-Muc) obtained. The synthesis at room temperature and neutral pH yielded nanoparticles with a spherical shape and an average diameter of 150 nm. The structure and properties of CuONPs-Muc were characterized using various methods and techniques, such as ultraviolet–visible spectroscopy (UV–vis), high-performance liquid chromatography (HPLC), one-dimensional polyacrylamide gel electrophoresis (1D-PAGE), up-conversion infrared spectroscopy Fourier transform (FTIR), scanning electron microscopy combined with energy dispersive spectroscopy (SEM/EDS), Raman spectroscopy and imaging, thermogravimetric analysis (TG-DSC), etc. Mucus proteins with molecular weights of 30.691 kDa and 26.549 kDa were identified, which are involved in the biogenic production of CuONPs-Muc. The macromolecular shell of proteins formed around the copper ions contributes to a higher efficiency of the synthesized CuONPs-Muc in inhibiting the bacterial growth of several Gram-positive (Bacillus subtilis NBIMCC2353, Bacillus spizizenii ATCC 6633, Staphylococcus aureus ATCC 6538, Listeria innocua NBIMCC8755) and Gram-negative (Escherichia coli ATCC8739, Salmonella enteitidis NBIMCC8691, Salmonella typhimurium ATCC 14028, Stenotrophomonas maltophilia ATCC 17666) bacteria compared to baseline mucus. The bioorganic synthesis of snail mucus presented here provides CuONPs-Muc with a highly pronounced antimicrobial effect. These results will expand knowledge in the field of natural nanomaterials and their role in emerging dosage forms.

1 January 2021 in Biotechnology & Biotechnological Equipment
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Journal Article
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EPEmiliya Ivanova Pisareva
Emiliya Ivanova Pisareva
ATAnna Atanasova Tomova
Anna Atanasova Tomova
VPVentsislava Yankova Petrova
Ventsislava Yankova Petrova
The budding yeast Saccharomyces cerevisiae is a widely used model organism to investigate the changes occurring in the eukaryotic cell and to predict its possible ‘reaction’ to different environmental factors. Recently it was also shown that these microorganisms possess another advantageous ability: to ‘enter’ into quiescent state (G0). Yeast G0 cells have similar physiological characteristics to those of higher eukaryotes making them a better model for toxicology studies. As cadmium could affect severely human health, the main aim of the present study was to use Saccharomyces cerevisiae quiescent cells to investigate the resistance potential and corresponding adaptive response of eukaryotic cells to elevated cadmium concentrations. Both diploid and haploid yeast strains in logarithmic, quiescent and non-quiescent state were exposed to different concentrations of Cd(NO3)2. The half-maximal inhibitory concentration (IC50) for all tested cell types was 100 µmol/L Cd(NO3)2. The deleterious effects of cadmium on intracellular macromolecule structures were analyzed through evaluating the levels of accumulated reactive oxygen species (ROS) and carbonylated proteins. The highest ROS concentration was measured in logarithmic cells: up to 50% versus about 8% in G0 cells. Significant damage in protein molecules was observed in haploid cells where the protein carbonylation reached levels of 25 µmol/mg. Studying the adaptive response to elevated Cd2+ concentrations revealed that quiescent and non-quiescent cells respond with increased expression of key elements from the antioxidant defense system: reduced glutathione, superoxide dismutase (SOD) and catalase. Furthermore, an additional SOD izoenzyme was detected when diploid and haploid cell populations were exposed to Cd2+.

7 May 2024 in Journal of Chemical Technology and Metallurgy
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NNNadezhda Dimitrova Nankova
Nadezhda Dimitrova Nankova
EPEmiliya Ivanova Pisareva
Emiliya Ivanova Pisareva
VPVentsislava Yankova Petrova
Ventsislava Yankova Petrova
ATAnna Atanasova Tomova
Anna Atanasova Tomova
Phytases, which perform the stepwise hydrolysis of phytic acid to myo-inositol and inorganic phosphate, are used worldwide to reduce phosphorus pollution and improve nutrition in monogastric animals and humans. Yeasts isolated from their natural environments represent rich and still underexplored sources of industrially valuable enzymes, including phytases; therefore, they are widely studied for the production of these enzymes. In this regard, thirteen yeast pure cultures were isolated from the microbial consortium of four types of sourdough obtained during the natural fermentation of different grain-based flours. Ten of the newly isolated yeast strains were selected as potential phytase producers based on their growth in liquid culture media with sodium phytate as the sole source of phosphorus. Using 18S rDNA and D1/D2 26S rDNA analyses, the species affiliation of the selected isolates was established. They referred to seven yeast species from 3 families, with the most significant representation of the family Saccharomycetaceae.Intracellular phytate-degrading activity was found in 8 isolates, the highest being in Nakaseomyces glabratus strain 7-4. The highest level of extracellular phytase was measured in Pichia membranifaciens strain 5-2. Both isolates showed significant antioxidant capacity higher than those of ascorbic acid.

1 January 2026
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Book Chapter
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MVMaksym Valetskyi
Maksym Valetskyi
ATAnna Atanasova Tomova
Anna Atanasova Tomova
The European airspace is undergoing its most significant structural transformation since the introduction of radar control, with private and hybrid entities now managing air traffic operations at dozens of airports across the United Kingdom, Spain and Sweden – the pioneering countries of TANS liberalisation. Despite their growing market significance, these providers remain analytically invisible: the prevailing benchmarking instruments, in particular the EUROCONTROL ATM Cost-Effectiveness (ACE) reports, were designed for a world of national monopolies and systematically exclude the very entities whose emergence catalysed the liberalisation process. This paper aims to close that information gap through three interrelated contributions. The paper synthesises knowledge on the transformation of the sector from traditional state monopolies to liberalised market models. The next chapter presents an empirical analysis of five key N-ANSPs. Using a proposed three-category framework (Category A – incumbent spin-offs, Category B – pure private players, Category C – PPP hybrid entities), their origins, product portfolios, strategic orientations and data availability are examined. Finally, the paper identifies four systemic gaps in the ACE benchmarking methodology and proposes a set of seven new key performance indicators (KPIs) specifically designed for the liberalised TANS market.