Department OF Microbial Genetics
Nedka Shivarova, MD, PhD’ Associate Professor
Head of Department
Tel: (+359 2) 979 31 14
E-mail:
Born1971 / MD in Human Medicine, Medical University, Sofia
1978 / MD in Medical Microbiology, Medical University, Sofia
Research Scientist, Institute of Microbiology, BAS
1987 / PhD in Microbiology, Institute of Microbiology, BAS
1990 / Associate Professor, Institute of Microbiology, BAS
Head of the Department of Microbial Genetics, Institute of Microbiology, BAS
1998 / Expert in environmental protection, Agency for Environmental Protection
Staff
Zlatka Alexieva, PhD, Associate Professor
Kantcho Lahtchev, PhD, Associate Professor
Svetla Danova, PhD, Associate Professor
Blagoy Atanasov, PhD, Research Scientist
Nadejda Peneva, Research Scientist
Maria Guerginova, PhD, Research Scientist
Dimitrina Liutzkanova, PhD, Research Scientist
Margarita Stoilova-Disheva, PhD, Research Scientist
Penka Petrova, PhD, Research Scientist
Galina Stoiantcheva, PhD, Research Scientist
Ralitza Alexandrova, MS, Research Scientist
Dionora Guliamova, PhD, Research Assistant
Vesselka Peltekova, Research Assistant
PhD Student
Jordan Manasiev, MS
Main Research Topics
· Genetic and enzymological studies on microbial degradation of xenobiotics by filamentous yeasts.
· Mathematical modelling of the phenol biodegradation process.
· Molecular taxonomic studies of lactic acid bacteria and bacilli.
· Biological activity and potential of lactic acid bacteria as bioprotective starters for dairy products and their probiotic properties for human health.
· Ecological studies of the mosquito pathogen Bacillus sphaericus.
· Molecular genetic investigation on some genes, involved in spectinomycin biosynthesis in Streptomyces.
· Genetic and enzymological studies on methilotrophic yeasts.
Most Important Achievements
· The physiological and biochemical peculiarities of the original yeast strain Trichosporon cutaneum R57, which is highly active in degrading many aromatic and aliphatic compounds – toxic pollutants of the environment were investigated. The biochemical analysis of the first three enzymes of the catabolic pathway of degrading phenol in carbonless media enhanced the elucidating of their key role in the process. A system for homologous and heterologous protoplast fusion and protoplast transformation of Trichosporon cutaneum R57 strain was elaborated. A specific oligoneucleotide probe was applied for the identification of microbial strains with the potential of degrading toxic aromatic compounds, isolated from polluted soils and waters. Dot-blot hybridization analysis for the identification of catabolic genes, coding enzymes with phenol-hydroxilase activity was carried out.
· Original approaches to the molecular-taxonomic characterization of lactic acid producing bacteria and the rapid monitoring of Lactobacilli from different ecological niches were developed.
· The genetic, physiological and other factors, controlling the sexual process of the yeast Hansenula polymorpha were investigated. Two special types of homothalism were uncovered: a copulation potential in all possible combinations and sporulation of haploid strains.
Selected Publications
Lyutskanova, D., Stoilova-Disheva, M. (2003): Expression of the spcN gene from Streptomyces flavopersicus in Escherichia coli and determination of the gene function. J. Biotechnol & Biotechnol. Eq. 17, 100-104.
Lyutskanova, D., Stoilova-Disheva, M., Peltekova, V. (2005): Increase in tylosin production by a commercial strain of Streptomyces fradiae. Appl. Biochem. Microbiol. 41, 165–168.
Lahtchev, K.L. (2002): Basic genetics of Hansenula polymorpha. In: G.Gellissen(ed) Hansenula polymorpha: biology and applications.Wiley-VCH, pp. 8-20.
Lahtchev, K.L., Semenova, V.D., Tolstorukov, I.I, van der Klei, I.-J., Veenhuis, M. (2002): Isolation and properties of genetically defined strains of the methylotrophic yeast Hansenula polymorpha CBS4732 . Archives of Microbilogy 177, 150-158.
Ozimek, P., Van Dijk, R., Lahtchev, K., Gancedo, C., Wang, D.Y., Van Der Klei, I.J., Veenhuis M. (2003): Pyruvate carboxylase is an essential protein in the assembly of yeast peroxisomal oligomeric alcohol oxidase. Molecular Biology of the Cell 14, 786-797.
Aleksieva, Z., Ivanova, D., Godjevargova, T., Atanasov, B. (2002): Degradation of some phenol derivatives by Trichosporon cutaneum R57. Proc. Biochem. 37, 1215–1219.
Alexieva, Z., Gerginova, M., Zlateva, P., Peneva, N. (2004): Comparison of growth kinetics and phenol metabolizing enzymes of Trichosporon cutaneum R57 and mutants with modified degradation abilities. Enzyme and Microbial Technology 34, 242-247.
Godjevargova, T., Ivanova, D., Aleksieva, Z., Burdelova, G. (2006): Biodegradation of phenol by immobilized Trichosporon cutaneum R57 on modified polymer membranes. Process Biochemistry 41, 2342-2346.
Gerginova, M., Manasiev, J., Shivarova, N., Alexieva, Z., (2007): Influence of various phenolic compounds on phenol hydroxylase activity of a Trichosporon cutaneum strain. Zeitschrift fuer Naturforschung 62c (in press).
Gerginova, M., Dimova, N., Ivanova, D., Alexieva, Z. (2007): Studies on biodegradation of aromatic pollutants by a Trichosporon cutaneum yeast strain. Bioremediation of soils contaminated with aromatic compounds, NATO Science Series: IV. Earth and Environmental Sciences, vol. 76.
Stoyancheva, G., Danova, S., Boudakov, I. (2006): Molecular identification of vaginal lactobacilli isolated from Bulgarian women, Antonie van Leeuwenhoek 90, 201-210.
Petrova, P., Miteva, V., Ruiz, J. A., del Solar G. (2003): Sequencing and analysis of the Streptococcus thermophilus plasmid pt38, Plasmid 50, 176-189.
Petrova, P., Gouliamova, D. (2006): Rapid screening of plasmid-encoded small hsp-genes in Streptococcus thermophilus, Current Microbiology 53, 422–427.
Danova, S.T., Stoyancheva, G., Manasiev, Y., Miteva V. (2005): Development and application of random DIG labelled probes based on total genomic Lactobacillus DNA, World Journal of Microbiology & Biotechnology 21, 835–842.
Danova, S., Petrov, K., Pavlov, P., Petrova, P. (2005): Isolation and characterization of Lactobacillus strains involved in koumiss fermentation, International Journal of Dairy Technology 58, 100-105.
Miteva, V., Boudakov, I., Ivanova-Stoyancheva, G., Mitev, V., Mengaud, J. (2001): Differentiation of Lactobacillus delbrueckii subspecies by ribotyping and amplified ribosomal DNA restriction analysis (ARDRA), J. Appl. Microbiol. 90, 909-918.