Projects / Programmes source: ARIS


Research activity

Code Science Field Subfield
4.02.01  Biotechnical sciences  Animal production  Genetics and selection 

Code Science Field
4.02  Agricultural and Veterinary Sciences  Animal and Dairy science 
Evaluation (rules)
source: COBISS
Researchers (10)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  07914  PhD Dušan Benčina  Veterinarian medicine  Researcher  2009 - 2012  223 
2.  29430  PhD Ivanka Cizelj  Biotechnology  Technical associate  2009 - 2012  51 
3.  05098  PhD Peter Dovč  Biotechnology  Researcher  2009  935 
4.  29431  PhD Daliborka Dušanić  Biotechnology  Junior researcher  2009 - 2012  42 
5.  16361  PhD Tanja Kunej  Animal production  Researcher  2009  913 
6.  05008  PhD Mojca Narat  Biotechnology  Head  2009 - 2012  688 
7.  24298  PhD Irena Oven  Animal production  Researcher  2011 - 2012  81 
8.  22446  PhD Brigita Slavec  Veterinarian medicine  Researcher  2009 - 2012  199 
9.  15658  PhD Simona Sušnik Bajec  Biochemistry and molecular biology  Researcher  2010 - 2012  194 
10.  08023  PhD Olga Zorman Rojs  Veterinarian medicine  Researcher  2009 - 2012  422 
Organisations (2)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0406  University of Ljubljana, Veterinary Faculty  Ljubljana  1627139  10,745 
2.  0481  University of Ljubljana, Biotechnical Faculty  Ljubljana  1626914  66,215 
Significance for science
Mycoplasmas and viruses represent two groups of pathogenic microorganisms with different way of life in frequently common hosts. Most previous studies were mainly focused on analyzing pathological differences and molecular mechanisms during individual infections. Our study has an emphasis on the analysis of common effects caused by the two pathogens and results are among few that are important for describing relationship between the host and both pathogens. The aim of this study was to determine host's immune response during mixed bacterial-virus infection. The model for our study was chosen based on previous experience and results from analyzing avian bacterial (M. synoviae) and virus (NDV, AIV) pathogens. We determined and described many mechanisms by which mycoplasmas influence host's cells (invading into host cells, influencing host's metabolic requirements, triggering apoptosis, inducing increased expression of metaloproteases; possessing nuclease, neuraminidase and protease activity) and confirmed that mycoplasma infection in various ways influences tissue degradation and lowers host's immune defense. We described the mechanism by which mycoplasmas induce autoimmune form of infectious synovitis. All results regarding mycoplasma infection were described for the first time and published in distinguished international journals. They represent new basic knowledge in mycoplasmology and immune response toward mycoplasma infection. Infections with mycoplasmas are often subclinical and frequently overlooked by diagnostics. Our study indicates that mycoplasma infection may have an important negative effect on host's immune capability, which may, after subsequent virus infection, affect disease development. This knowledge is also important for understanding consecutive infections in other animals and humans, where human mycoplasmas are thought to influence the development of various diseases, including induction of autoimmune arthritis. We also analyzed the response of developing immune system in chicken embryos toward consecutive mycoplasma-virus infection. The in vitro experiment on chicken embryonic fibroblast cell line confirmed that every microbe activated a certain group of immune genes, while the presence of both pathogens altered those gene expression profiles. Gene expression analysis of chicken embryos following infection with M. synoviae, NDV or consecutive infection with both pathogens was first suchlike experiment that showed differences in gene expression after each type of infection and also between different organs. This data is significant for understanding early molecular events in the activation of immune response, which is important especially at vertical transmission of the infection through hatching eggs, e.g. M. synoviae. We showed that mycoplasma infection modulated expression of more genes in different extent than virus infection. For every type of infection we analyzed expression of immune genes in several organs and determined which genes were significantly modulated in every organ separately. In consecutively infected embryos we determined inhibition of mycoplasma-induced genes, most likely affected by the presence of the virus. These are novel findings, important for understanding immune processes and also for predicting the outcome of vaccinations in animals and humans. Our results may contribute the data necessary for planning vaccine components and time intervals for animal and human vaccinations. Although the study was performed on microbes that infect poultry, our results have importance from the aspect of unpredictable events in the occurrence of bird flu where the avian influenza virus type H5N1 changed hosts and also infected humans. Mycoplasmas also cause subclinical respiratory infections in humans, which makes understanding of molecular mechanisms triggered by these pathogens relevant also for human medicine.
Significance for the country
Poultry products (meat, eggs, and their byproducts) already represent 50% protein of animal origin in human diet, making poultry one of the most important livestock branches in Slovenia. Infectious diseases caused by bacteria, including M. synoviae and M. gallisepticum, and viruses cause major economic losses that may be also influenced by avian influenza virus H5N1 spreading. Here additional concerns exist, because H5N1 infection can spread to humans. Regarding the expected gradual termination of antibiotic usage in livestock production, the situation may become even more difficult and new procedures for reducing economic damage and infections necessary. New relevant results were gained in our study in the sense of understanding interactions between pathogens on molecular level and their mutual effect to the host. Molecular events during mycoplasma infection have been clarified in detail, which can be present in animal (and human) populations in a subclinical form and may be transferred vertically in poultry. Thus, vaccination against viruses is performed on previously mycoplasma-infected host. In intense poultry industry with the absence of antibiotic treatment, understanding these mechanisms is essential. In current livestock conditions, use of new knowledge could reduce economic losses which are often caused by consecutive infections with mycoplasmas and viruses from attenuated vaccines. Designing new vaccination preparations and vaccination strategies is based on the knowledge as obtained in our study. Mycoplasmas and viruses are pathogenic microorganisms that cause difficulties in pig and ruminant (cattle, sheep, and goat) farms as well. Information gathered in this project could be useful for understanding and solving problems involving other animal species which may bring positive effects to the economy, especially in stockbreeding and veterinary sciences. Vaccines are still largely produced by using chicken embryos for virus propagation which makes information, how vertically transmitted M. synoviae infection affects virus propagation and what are the mutual effects of both pathogens on the embryo, welcome for understanding the mechanisms that influence embryo mortality. Mycoplasma infections of cell lines that are widely used for various researches and represent useful models for analyzing numerous mechanisms (pharmacy, cosmetic industry, toxicology, ecology) are frequent and often unnoticed. We estimate that our data is important for the correct evaluation of results, acquired using cell lines. Human infections with human mycoplasmas are frequent especially in kindergartens, schools and hospitals and are often subclinical and underestimated in diagnostics. Results acquired from animal models show that mycoplasma-infected organisms can be much more susceptible for subsequent virus infection and that the effect of virus infection differs when mycoplasmas are additionally present in the host. Influence of mycoplasma infection on the course of HIV infection in known. Mycoplasma pneumoniae is a frequent pathogen in hospitals where infected individuals are susceptible for subsequent virus infections which significantly prolongs the time of staying in the hospital. Our results have special importance for understanding disease development following avian influenza virus H5N1 infection whose natural hosts are birds.
Most important scientific results Annual report 2009, 2010, 2011, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2009, 2010, 2011, final report, complete report on dLib.si
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