The work was published in one of the most prominent scientific journal in world, namely Proceedings of the National Academy of Sciences of the United States of America which has 5 year impact factor of 10.5. In this work, we address a social process called Quorum Sensing (QS) where bacteria secrete and share signalling molecules that bind to specific receptors and induce adaptive responses within the population. We use the ComQXP QS system of Bacillus subtilis to study the intracellular co-dependence of two essential QS functions: signal production and signal response. We demonstrate that the QS signal-deficient mutants have a responsive QS system, disturbed balance between the primary and secondary metabolism and overproduce the secondary metabolite surfactin in the presence of exogenously provided signal. Such mutants fail to compete with the socially active signal producers due to surfactin-related mechanisms that discriminate the two populations. We propose that a constraint on signal production preserves QS functionality in the natural microbial populations. The work addresses one of the most interesting and studied Gram positive bacterium which has wide industrial applications, is used as biopesticide and probiotic and is problematic in food spoilage due to its ability to form spores. The work was indicated on Subtiwiki site as the best paper in March 2014, it was chosen among the best published papers at the University of Ljubljana, which were published in the period of 2013-2014 and RTV Slovenia 1 featured a story about cheating bacteria and our research achievemnets.
COBISS.SI-ID: 4358008
The work addresses the diversity and evolution of the comQXPA locus of Bacillus subtilis which encodes a quorum sensing (QS) system typical of Gram positive bacteria. It encodes four proteins, the ComQ isoprenyl transferase, the ComX pre-peptide signal, the ComP histidine kinase, and the ComA response regulator. These are encoded by four adjacent genes all situated on the same chromosome strand. We performed an extensive bioinformatics resulting in comprehensive census of comQXPA-like gene arrangements in 2620 complete and 6970 draft prokaryotic genomes. We found 39 novel com-like predictions revealing for the first time that in addition to B. subtilis and close relatives, 20 comQXPA-like loci are also present in other Firmicutes, even in Clostridiales. We also discovered differences in gene-overlap patterns in comQXPA loci in B. subtilis-like and non-B. subtilis-like clades. Pronounced sequence variability associated with the ComX peptide in B. subtilis clade that is a signature of pherotype (signalling specificity groups) evolution is also evident in the non-B. subtilis clade suggesting grossly similar evolutionary constraints in the underlying quorum sensing systems.The paper has been already cited.
COBISS.SI-ID: 4381048
Peatlands play an important role in emissions of the greenhouse gases CO2, CH4 and N2O, which are produced during organic matter mineralization. To examine the influence of soil type (fen, bog soil) and environmental factors (temperature, groundwater level), emission of CO2, CH4 and N2O, soil temperature and groundwater level were measured weekly or biweekly in loco over a oneyear period at four sites located in Ljubljana Marsh, Slovenia using the static chamber technique. The study involved two fen and two bog soils differing in organic carbon and nitrogen content, pH, bulk density, water holding capacity and groundwater level. The results indicated that the examined peatlands emit similar amounts of CO2 and CH4 to peatlands in Central and Northern Europe and significantly higher amounts of N2O. This article was published in the number one journal in the field of soil and it has been cited already 26 times.
COBISS.SI-ID: 3779192
Responsibility for food safety must be taken through the entire food-production chain, to avoid consumer cross-contamination. The antimicrobial activities of an Alpinia katsumadai seed extract and epigallocatehin gallate (EGCG), and their combination, were evaluated against individual food-borne pathogenic strains of Listeria monocytogenes, Escherichia coli and Campylobacter jejuni, individually and as a cocktail, in chicken-meat juice and sterile minced meat as food models, and in minced meat with the naturally present microflora, as an actual food sample. The antibacterial efficiencies of the tested combinations are influenced by storage temperature. Food safety can be improved by using the appropriate combination of natural antimicrobials to reduce the microbiological risk of minced meat.
COBISS.SI-ID: 4334968
The effects of a fractionated 70 % ethanolic extract of propolis were analyzed at the subproteome level by two-dimensional electrophoresis. Differential detergent fractionation was used to fractionate proteins from the yeast Saccharomyces cerevisiae according to their subcellular localization. Thus, four subcellular proteomes were obtained: cytosolic, membrane/organelle, nuclear, and cytoskeletal. Yeast treatment resulted in changes in the levels of proteins involved in carbohydrate and energy metabolism, antioxidant defense, actin filament dynamics, folding of proteins, and others. On the basis of this information, we can obtain better insights into the processes that are carried out in cells exposed to propolis extract. This paper that was published in the top journal in the field of agrochemistry also signifies our ability to perform advanced proteomics and subproteomics analysis of microorganisms.
COBISS.SI-ID: 4320376