All buoyant genera and species of cyanobacteria are at least periodically exposed to higher irradiation during their vertical migration to the surface that usually occurs several times a day. The aim of the study is to assess the influence on cyanobacteria of UVB radiation at realistic environmental intensities. UVB exposure causes damage to the genetic material, cytoskeletal elements, higher sedimentation rates and consequent cell death. In contrast to microcystin producers, the microcystin non-producing strain is more susceptible to the deleterious effects of radiation, with weak recovery ability. The ecological relevance of the results is discussed using data from eleven years’ continuous UVB radiation measurements within the area of Ljubljana city (Slovenia, Central Europe). Our results suggest that increased solar radiation in temperate latitudes can have its strongest effect during cyanobacterial bloom formation in spring and early summer. UVB radiation in this period may significantly influence strain composition of cyanobacterial blooms in favor of microcystin producers.
COBISS.SI-ID: 2888271
Cyanobacterial cytotoxin cylindrospermopsin (CYN) is increasingly found in surface freshwaters, worldwide. It poses a potential threat to humans after chronic exposure as it was shown to be genotoxic in a range of test systems and is potentially carcinogenic. In the present study in HepG2 cells CYN induced formation of DNA double strand breaks (DSBs), morphological changes and cell cycle arrest. The results provide new evidence that CYN is a direct acting genotoxin, causing DSBs, and these facts need to be considered in the human health risk assessment.
COBISS.SI-ID: 2856527
In our daily life we are more often exposed to photocatalytically (with UV) activated anatase particles of TiO2. Studies have shown that in the presence of UV irradiation toxicity and genotoxicity of TiO2 is higher. In our study we wanted to see whether toxicological properties of UV-irradiated TiO2 particles differ from non-irradiated in the absence of UV irradiation. Because of that we pre-irradiated anatase nano- and submicron-sized TiO2 particles with UV and then, after the UV irradiation has been discontinued, we tested their cyto- and genotoxicity in comparison with non-irradiated particles. We have shown that cyto- and genotoxic potential of UV pre-irradiated TiO2 anatase particles drastically increases, irrespective of the particle size. This is the first study, which showed that after pre-irradiation of TiO2 particles with UV their toxic potential drastically increases.
COBISS.SI-ID: 2430031
In this work we studied how the most abundant stromal cells in glioblastoma (GBM), i.e. endothelial cells and macrophages influence the phenotype of GBM cells. Stromal cells did not impact proliferation of tumour cells, but enhanced their invasion and reduced the triggered apoptotic response. On the other hands, GBM cells stimulate proliferation of stromal cells. We concluded that stromal cells create then environment, which facilitates and contributes to the development of GBM. GBM cells stimulate the growth of these cells thereby assuring a better environment for tumour progression.
COBISS.SI-ID: 2086991
In this study we have investigated the interaction of human mesenchymal stem cells (MSCs) and tumor cells, fundamental for MSC’s cellular treatment vectors design. We demonstrated that in gliomas, the recruitment of MSC is driven by glioma-secreted factors. We showed that glioma cells as well as MSCs differentially express connexins by which they interact via gap-junctional coupling to form functional and structural syncytium, which are responsible for cells’ phenotype change. The described phenomena provides new insight into the complexity of interactions between tumor cells and host MSCs
COBISS.SI-ID: 2501199