Projects / Programmes
Molecular Biology of Microorganisms
January 1, 2004
- December 31, 2008
| Code |
Science |
Field |
Subfield |
| 1.05.00 |
Natural sciences and mathematics |
Biochemistry and molecular biology |
|
| 3.01.00 |
Medical sciences |
Microbiology and immunology |
|
| 4.06.00 |
Biotechnical sciences |
Biotechnology |
|
| Code |
Science |
Field |
| B230 |
Biomedical sciences |
Microbiology, bacteriology, virology, mycology |
Bacteria, Archeae, Fungi, resistance, virulence, genetical mechanisms, antibiotics, halocins, membrane, transport, plasmids, regulation of gene expression, biosynthesis, transformation, conjugation, evolution, halophiles, psychrophiles
Researchers (8)
Organisations (1)
Abstract
Microorganisms are the most successful of organisms due to their exceptional metabolic diversity and successful competition for nutrients and space. For this purpose they: 1. synthesize antibiotics, 2. develop defence against antibiotics and 3. inhabit extreme environments.
1. Microorganisms are the causative agents of numerous diseases however, only if they can overcome the defence mechanisms of the host, successfully compete with other microorganisms and spread within the host. By interfering with the synthesis of virulence factors the infective process can be interrupted however, only if the mechanisms of their synthesis are understood.
Colicins are bacteriocins synthesized by Escherichia coli strains and act specifically against cells of the same or related species. They are thus antibiotics of a narrow range of activity which can destroy enteropathogens but not the remaining microbial flora. The goals and expected results of the proposed research are: understanding expression of colicin K as a basis for more efficient production of bacteriocins which would be used for therapeutic purposes, as well as a model for the elucidation of mechanisms which regulate virulence determinants of bacteria within a population of bacterial cells.
2. Microorganisms are successful also due to the synthesis of antimicrobial compounds. An example is the Bcr transporter from Bacillus licheniformis which mediates resistance against the peptide antibiotic bacitracin. Bcr is a member of the family of ABC transporters which can be either specific for a certain compound, for example an antibiotic or, nonspecific such as "multidrug resistance" proteins. It is interesting that both bacterial cells resistant against bacitracin due to the bacitracin transporter, as well as human cells with the P-glycoprotein exhibit sensitivity to detergents. Among the proteins that compose the Bcr transporter, the key protein is the transmembrane BcrC. We have found that BcrC is related to the PAP2 superfamily of proteins as well as that, it exhibits phosphatase activity. Our results indicate that BcrC is an essential bacterial protein. The aim of our planned research work is to elucidate BcrC's essential role.
3. Among the extreme environments are those with a low temperature and a high concentration of NaCl. In such environments fungi have until recently been unknown. We were first to describe extremophilic fungi in the waters of the Sečovlje salterns and in waters with extremely high NaCl content from three continents. Recently, studies of fungi in the extremely cold environment of the Arctic as well as extremely halophile Archaea have been commenced. Halophile and psychrophile fungi belong to the rare extremophile eukaryotes. As such they will be a valuable source of new biotechnological products with special characteristics and unique models for the studies of adaptation of cellular biomolecules to extreme conditions. The isolated fungi will be identified using classical and molecular techniques, with emphasis on determination of new species. On the level of physiological studies we will focus on adaptation of cell wall components, gene regulation of melanin synthesis, lipid composition of the membrane, its fluidity, participation of rafts, production of compatible solutes at high salt conditions and low temperatures, as well as ion concentration in the cytoplasm in relation to function of membrane ion pumps.
Halophile Archaea are important producers of biologically active substances, halocins. Different halocins will be studied at the protein and genetic level. Following isolation of halophile Archaea, biochemical and phylogenetic analysis will be used to identify the isolated strains and determine the production of halocins. These will be biochemically characterized. By studying the interaction of halocins with lipid membranes we will try to elucidate the mechanism of halocin action.
Significance for science
Colicins are antibiotics with a narrow range of activity and are interesting as potential antimicrobial substances which destroy enteropathogens but not the microbiota of the intestinal tract. Destruction of the microbiota with broad spectrum antibiotics can lead to pseudomembranous colitis. Elucidation of colicin K expression is the basis of more effective production of bacteriocins which could be employed for therapeutic purposes. Colicin synthesis is associated with bacterial secondary metabolism including antibiotic synthesis, secretion of various proteins as well as sporulation. In depth knowledge of regulation of colicin synthesis will allow more efficient exploitation of bacteria for pharmaceutical purposes. Studies of extremophiles have recently become a priority of research programs financed by the European commission and the biotechnological industry. Studies are focused at three main groups, halophiles, psychrophiles and thermophiles as well as alkalophiles and acidophiles. An interdisciplinary approach encompasses isolation/taxonomy, physiology/biochemistry and molecular biology/ genetics. Areas of special interest are those with biotechnogical potential. Progressive soil salination in areas which are, due to global warming, and consequently greater aridity irrigated, represents one of the main worldwide agricultural problems. On a global scale, annually 50% of artificially irrigated areas are lost, that is 10 million hectares of agricultural surfaces. Due to such trends, our research represents an important contribution to understanding halophile mechanisms with regard to increasing tolerance to salt among agriculturally significant plants, as well as desalination of soil employing bio or phytoremidiation. An important step towards such a goal is understanding mechanisms of salt tolerance particularly of eukaryotic halophilic organisms. Further, taxonomic analysis are a prerequisite for selection of appropriate model organisms, which are investigated at different levels by researchers at other institutions, such as, the Institute for Biochemistry of the Medical Faculty, Ljubljana (prof. dr. Ana Plemenitaš). In addition, knowledge of the structure and mechanisms of action of archeocins will enable clinicians to determine which archeocine exhibit appropriate pharmaceutical effects.
Significance for the country
Introduction of new techniques in the field of bacterial genetics and taxonomy of fungi such as, secondary metabolites and molecular analysis of various parts of rDNA or genomic DNA to identify organisms, is an important contribution for the development of taxonomy of fungi as well as the search for new antimicrobial agents in Slovenia. We are involved in the mangement of the natural park Sečovlje. the latter has obtained, due to our research, formal protection of diversity in the active part of the salterns at the level of the Ministry for environment.
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