Section of MYCOLOGY
Head: Professor Maria Angelova, DSc
Tel: +359 2 979 31 26
Assist. Professor Ekaterina Tsankova Krumova, PhD
Теl: + 359-02-979-31-33, e-mail: email@example.com
Assist. Professor Radoslav Ignatov Abrashev, PhD
Теl: +359-02-979-31-28, e-mail: firstname.lastname@example.org
Svetlana Bojanova Pashova,
Теl: + 359-02-979-31-33, e-mail: email@example.com
Assist. Professor Vladislava Georgieva Dishliiska,
Теl: + 359-02-979-31-28,e-mail: firstname.lastname@example.org
Assist. Professor Jeni Georgieva Miteva-Staleva, MS
Теl: + 359-02-979-31-28,e-mail: email@example.com
Researchеr Borjana Kancheva Spasova,
Теl: + 359-02-979-31-28
Technican Emilia Eftova,
Main scientific field
Research within the Group is focused on filamentous fungi, isolated from various sources (including Antarctic samples) at different levels: molecular, cellular, whole organism and biocenotic.
Main Research Topics
- Taxonomic identification of fungal species;
- Fungal morphology, physiology and biochemistry under normophysiological and stress conditions;
- Fungal cell response against different type of stresses such as oxidative stress, heat- and cold shock, stress of immobilization and heavy metal exposure; evaluation of oxidative stress biomarkers; antioxidant enzyme defence;
- Fungal cell factories for production of valuable biological-active compounds by free and immobilized cultures; cold-active enzymes; regulatory mechanisms in the biosynthesis; purification and characterization of enzymes;
- Fungal biodegradation of natural and synthetic polymers (wood, leather, textile, historical records, etc.); laboratory expertise, consultations, instructions for preservation and elimination of fungi; mechanism of action of fungicide substances; methods for application of fungicides.
1. Fungal diversity
A sizeable fungal collection was developed along with the isolation of strains from temperate and extreme environments. There are species from the three major groups of true fungi: Basidiomycota, Ascomycota and Zygomycota. Most of them were identified by genus and species. According to the temperature range for growth, they were classified as extremely psychrophilic, psychrotrophic or mesophilic fungi. Antarctic strains were isolated from samples taken from different sources.
2. Oxidative stress (OS)
We focus our attention on better understanding OS response in lower multicellular eukaryotes. Filamentous fungi from different species are using as model microorganisms. Treatment of the fungal strains with various stimuli generating reactive oxygen species (ROS) induces a state of oxidative stress. Related research targets evaluation of: (1) stress biomarkers (cyanide-resistant respiration; direct assessment of ROS production; oxidative damaged proteins; synthesis of reserve carbohydrates etc); (2) antioxidant enzyme defence (superoxide dismutase, SOD and catalase, CAT); (3) subcellular localization of SOD isoenzymes; (4) changes in activities of key enzymes from basic metabolite pathways. Evidences, based on electrophoretic mobility, sensitivity to SOD inhibitors, and immunoblot analysis support the unusual existence of Cu/Zn-SOD in mitochondrial intermembrane space (IMS) while the Mn-SOD was in the matrix. Enzyme activity is almost equally partitioned between both compartments, thus suggesting that the IMS could be one of the major sites of exposure to superoxide anion radicals. The H. lutea mitochondrial Cu/Zn-SOD is the first identified naturally glycosylated enzyme, isolated from IMS.
3. Relationship between OS and other types of stresses
- Cu-induced stress. Our results provide additional evidences for OS mediating copper toxicity in filamentous fungi. Biomarker response to the heavy metal was quite equal with treatment involving a more direct application of ROS, such as paraquat. Adaptive response to heavy metal treatment refers to the ability of cells to better resist the damaging effects of the toxic agent when first preexposed to a lower dose.
- Heat-shock. Another particular area of interest concerns the hypothesis of a common signal for heat shock (HS) and OS. Evidence is provided for the possibility that the OS plays a major role in the effect of enhanced temperature in Aspergillus niger. The treatment resulted in increase in cyanide-resistant respiration, ROS generation, corresponding accumulation of the reserve carbohydrates (trehalose and glycogen), increase in protein carbonyl content, and activation of antioxidant enzyme defense. This knowledge may be of importance in controlling both fermentation and pathogenicity.
- Metabolite adaptation to cold temperatures. Antarctica and the life of filamentous fungi in the extreme environment are also an interest of our research group. The effect of temperature down shift on cell response of Antarctic fungi are comparing with this in European temperate strains. The main finding is that the fungal strains may have evolved a specialized physiology allowing them to survive prolonged low temperatures, and have enzyme systems that function at low temperatures. Compared to temperate mesophilic strains, Antarctic fungi (psychrophilicand mesophilic) demonstrated adaptations, which permit survival in low-temperature conditions.
- Stress of immobilization. Our results clearly demonstrated that immobilization influences the physiological behavior of fungal cells. Immobilized A. niger cells showed significant increase in activities of key enzymes of the glycolytic pathway, pentose shunt, and tricarboxylic acid cycle compared to the free cell culture. Moreover, immobilization elicits the enhanced synthesis of antioxidant enzymes that demonstrate an association between state of immobilization and oxidative stress.
4. Fungi as cell factories for production of valuable biological-active compounds
- Original fungal strains producers of biological-active compounds such as enzymes and alkaloids were isolated and characterized. We have a well-established expertise in production of elimoclavine, pectinase, proteinases etc. on laboratory and semi-industrial scale level.
- High effective technology for biosynthesis of naturally glycosylated Cu/Zn-SOD by the fungal strain Humicola lutea 103 (HLSOD) was elaborated. The novel enzyme exerts a far higher pharmacological activity than non-glycosylated enzymes. HLSOD was fully characterized and used in in vivo models for the demonstration of its protective effect against myeloid Graffi tumor in hamsters and influenza virus infection. Furthermore, the antioxidant enzyme improves fertility of ram and bull spermatozoa during liquid storage and cryoconservation.
- A new direction in our work are physiological and biochemical investigations of the biosynthesis and regulation of activity of valuable cold-active enzymes in psychrophilic and psychrotrophic fungi, using existing collections of Antarctic strains.
5. Fungal biodegradation of natural and synthetic polymers
Due to the current knowledge about morphology and biochemistry of the filamentous fungi, as well as the professional experience some methods concerning the preservation of natural polymers from fungal biodegradation were developed.
Granted by International Organizations
- Superoxide dismutase by Aspergillus niger: heat shock-induced biosynthesis and structural characterization (LST.CLG 980520, with Prof. B. Salvato, Padua, Italy); Science for Peace and Security, NATO.
- Microbiological and ecological responses to global environmental changes in Polar regions, International Polar Year 2007 – 2008.
- Effective education of PhD students and upport of development and realization of post-doctoral students and young scientists in priority areas of Microbiology (European Social Fund, Operational Programme “Human Resources Development” , grant BG051PO001-3.3.04/32.
- Cold-adaptation of Antarctic fungi and their application
(D-r . Tosi, University of Pavia, Italy)
- Biotechnological production of cold-active enzymes by fungi
(D-r . Tosi, University of Pavia, Italy)
Granted by National Funds
- Fungal superoxide dismutase: adaptation to oxidative stress andconformational control of enzyme activity (К-1302), The National Science FundMinistry of Education and Science.
- Biological role of the antioxidant defense in filamentous fungi, isolatrd from Antarctica (B-1309), The National Science Fund of Ministry of Education and Science.
- Biological function of antioxidant enzymes in cell respons of Aspergillus niger against temperature stress (K-1401), The National Science Fund of Ministry of Education and Science;
- Metabolic cold-adaptation in Antarctic fungi (VU-B-205/06, with Prof. I. Ivanova), The National Science Fund of Ministry of Education and Science.
- Effect of Cu/Zn-SOD produced by Humicola lutea on sperm function and antioxidant defense of Bosstaurus in in vitro storage (with Prof. Z. Zachariev), Ministry of Agriculture and Forestry.
- Biological monitoring for conservation and restauration of culturalmonuments in Bulgaria (VU-B-302/07, with Prof. V. Groudeva), The National Science Fund of Ministry of Education and Science;
- Novel cold-active superoxide dismutase from Antarctic fungi:biotechnological production, chemical characterization and application (DO002-172/08), The National Science Fund of Ministry of Education and Science.
- Wild small fruits species in Bulgaria - a valuable resource for human health (DО02-334/08), The National Science Fund of Ministry of Education and Science.
- Angelova, M., S., Pashova, L. Slokoska. Comparison of antioxidant enzyme biosynthesis by free and immobilized Aspergillus niger cells. Enzyme Microbiol. Technol. 2000, 26, 544-549.
- Angelova, M., P. Dolashka-Angelova, E. Ivanova, J. Serkedjieva, L. Slokoska, S. Pashova, R. Toshkova, S. Vassilev, I. Simeonov, H-J. Hartmann, S. Stoeva, U. Weser, W.Voelter. A novel glycosylated Cu/Zn-containing superoxide dismutase: production and potential therapeutic effect. Microbiology (UK), 2001, 147, 1641-1650.
- Stefanov R., Angelova, M., Stefanova Z., Subev M., Dolashka P., Voelter W., Zachariev Z. Cu/Zn-Superoxide dismutase from the fungal strain Humicola lutea 103 improves ram spermatozoa functions during liquid storage. Andrologia, 2004, 2, 51-56.
- Dolashka-Angelova P., Stevanovic S., Dolashki A., Angelova M., Pashova S., Krumova E., Serkejieva J., Zacharieva S., Voelter W. Structural and functional analyses of glycosylated Cu/Zn-SOD from the fungal strain Humicola lutea 103, cultivated in copper stress conditions. Biochem. Biophys Res Com, 2004, 317, 1006-1016.
- Angelova M., Pashova S., Spasova B., Vassilev S., Slokoska S. Oxidative stress response of filamentous fungi induced by hydrogen peroxide and paraquat. Mycol. Res. 2005, 109 (2), 150-158.
- Sokmen M., M. Angelova, E. Krumov, S. Pashov, S. Ivanchev, A. Sokmen, J. Serkedjieva. In vitro antioxidant activity of polyphenol extracts with antiviral properties from Geranium sanguineum L. Life Sci. 2005, 76, 2981-2993.
- Abrashev, R., P. Dolashka, R. Christova, L. Stefanova, M. Angelova Role of antioxidant enzymes in survival of conidiospores of Aspergillus niger 26 under conditions of temperature stress. J. Appl. Microbiol. 2005, 99, 902-905.
- Elena Kovacheva, Milen Georgiev, Svetlana Pashova, Maria Angelova, and Mladenka Ilieva Radical Quenching by Rosmarinic Acid from Lavandula vera MM Cell Culture Z. Naturforsch. 2006, 61c, 517-520.
- Gocheva, Y., Krumova, E., Slokoska, L., Miteva, J., Angelova, M. Cell response of Antarctic and temperate strains of Penicillium spp. to different growth temperature. Mycol. Res. 2006, 110, 1347-1354.
- Stefanov R., E. Krumova, M. Angelova, P. Dolashka, W. Voelter and Z. Zachariev (2006) Artificial Insemination of Sheep and Cow with Semen Treated by Cu/ Zn-superoxide Dismutase from the Fungal Strain Humicola lutea 103. W J Zoology, 1, 1, 36-39.
- Krumova, E., Dolashka-Angelova, P., Pashova, S., Stefanova, L., Van Beeumen, J., Vassilev, S., Angelova M. Improved production by fed-batch cultivation and some properties of Cu/Zn-superoxide dismutase from the fungal strain Humicola lutea 103. Enzyme Microb Technol 2007, 40, 524-532.
- Angelova M. B. Microbial pectinases: Application in horticultural industries In: Microbial Biotechnology in Horticulture, eds. Ray, R.C., Ward, O.P. 2008, Vol 3, 101-180, Science Publishers Inc. Enfield ISBN 978-1-57808-520-0
- Krumova, E., Dolashki, A., pashova, S., Dolashka-Angelova, P., Stevanovic, S., Hristova, R., Stefanova, L., Voelter, W., Angelova M. Unusual location and characterization of Cu/Zn-containing superoxide dismutase from filamentous fungus Humicola lutea. Arch. Microbiol. 2008, 189, 121-130
- Dolashki, A., Abrashev, R., Stevanovic, S., Stefanova, L., Abasid, A., Velkova, L., Hristova, R., Angelova M., Voelter, W., Devreese, B., Van Beeumen, J., Dolashka-Angelova, P. Biochemical properties of Cu/Zn-superoxide dismutase from fungal strain Aspergillus niger 26 Spectrochimica Acta Part A 2008, 71, 3, 975–983
- Abrashev R. I., Pashova S.B., Stefanova L.N., Vassilev S.V., Dolashka-Angelova P.A., Angelova M. Heat-shock-induced oxidative stress and antioxidant response in Aspergillus niger 26. Can J Microbiol 54, 2008, 12, 977-983
- Krumova, E., Pashova, S., Dolashka, P., Stefanova, Tz., Angelova M. Biomarkers of oxidative stress in the fungal strain Humicola lutea under copper exposure. Process Biochem 2009, 44, 288–295
- Gocheva Y., Tosi S., Krumova E., Slokoska L, Miteva J., Vassilev S., Angelova M. Temperature downshift induces antioxidant response in fungi isolated from Antarctica. Extremophiles 2009, 13, 273–281, 1431-
- Georgiev M., Abrashev R., Krumova E., Demirevska K., Ilieva M., Angelova M. Rosmarinic acid and antioxidant enzyme activities in Lavandula vera MM cell suspension cultures: a comparative study. Appl Biochem Biotechnol, 2009, 159(2), 415-425.
- Dicheva, V., Pashova, S., Groudeva, Ts., Groudeva, V., Angelova, M.Filamentous fungi from Rila monastery: isolation and growth characterization. Biotechnol. & Biotechnol. Eq. 2009, 23, 188-191
- Kostadinova N., Krumova E., Tosi S., Pashova S., Angelova M.. Isolation and identification of filamentous fungi from island Livingston, Antarctica. Biotechnol. & Biotechnol. Eq. 2009, 23, 267-270.
- Abrashev, R., Engibarov, S., Еneva, R., Abrashev, I., Angelova, M. Superoxide dismutase and catalase activities in Vibrio cholerae non-O1 strains. Biotechnol. & Biotechnol. Eq. 2009, 23, 473-476.
- Dineva J., Vangelov I., Abrashev R., Gulenova D., Nikolov G., Аngelova М., Ivanova М. Survival role of intracellular superoxide dismutases SODs and Catalase for human granulosa luteinized cells: A preliminary study. Compt Rend Bulg Acad Sci 2010, 63, 10, 1463-1469.
- Tosi S., Kostadinova N., Krumova E., Pashova S., Dishliiska V., Spassova B., Vassilev S., Angelova M. Antioxidant enzyme activity of filamentous fungi isolated from Livingston Island, Maritime Antarctica. Polar Biol. 2010, 33, 1227–1237
- Georgiev M., Alipieva K., Pashova S., Denev P., Angelova M., Kerns G., Bley T. Antioxidant activity of devil’s claw cell biomass and its active constituents. Food Chemistry, 2010, 121, 967–972.
- Georgiev M., Alipieva K., Orhan I., Abrashev R., Denev P., Angelova M. Antioxidant and Cholinesterases Inhibitory Activities of Verbascum xanthophoeniceum Griseb. and Its Phenylethanoid Glycosides. Food Chemistry, 2011, in press.