Endophytic bacteria from Capsicum annuum var. grossum cultivars and their inhibitory effects on Listeria monocytogenes

Endophytic microorganisms living inside plant tissues might have numerous positive effects on the host plants. Endophytes can promote the growth and yield of the plant, help to remove contaminants from the tissues, and can suppress growth of pathogens; however, some enteric human pathogenic bacteria have also been isolated as endophytes. The aims of our study were the characterisation and identification of endophytic coliform bacteria isolated from different cultivars of sweet pepper (Capsicum annuum var. grossum) using a selective (VRBL) agar medium, and determination of antagonistic interactions between these endophytes and Listeria monocytogenes. The bacterial isolates showed heterogeneity based on their phenotypic and genotypic properties. Results of identification by molecular biological methods also confirmed the presence of different genera/species. When the antagonistic effect of the isolated endophytic bacteria was tested it was found that one isolate — identified as Pseudomonas putida — showed significant inhibition on the growth of Listeria monocytogenes

Colonization ability of Escherichia coli and Listeria monocytogenes in the endosphere of sweet pepper (Capsicum annuum var. grossum)

Fruits and vegetables can be transmission vehicles of human opportunistic and obligate pathogenic bacteria, persisting in inner tissues for shorter or longer periods or colonizing the plants as facultative endophytes. In this study we investigated the ability of commensal E. coli and pathogenic L. monocytogenes strains to internalize sweet pepper seedlings via seed bacterization, as germinating seeds and roots are important infiltration sites for entry of enteric bacteria. By combining cultivation dependent and independent (PCR and FISH-CLSM) techniques we could not detect stably or transiently colonized inoculated bacteria in 6–7 weeks old pepper seedlings, suggesting that there is low risk associated with internalized enteric or human pathogenic bacteria via germinating seeds in sweet pepper

Effects of a Nuclear Power Plant Warmwater Outflow on Environmental Conditions and Fish Assemblages in a Very Large River (the Danube, Hungary)

Direct or indirect effects of nuclear power plants' (NPPs) warmwater effluents on the structure of biotic assemblages are poorly known in very large rivers. We examined changes in physical habitat structure, temperature condition and their possible effects on the structure of Danubian fish assemblages due to the outflow of the Paks NPP's warmwater channel, in Hungary. Seasonal surveys conducted both upstream and downstream from the outfall showed that its hydromorphological effects were generally local and comparable to natural or other anthropogenic hydromorphological changes. The effect of the returned cooling water was more apparent in the seasonally recorded surface water temperatures and depended highly on the spatial positioning of the sampling sites. However, environmental and spatial variables accounted only for a low amount of variance in case of both shoreline and offshore fish assemblage data. Overall, we found that the outflow exerted only a local scale effect on the structure of Danubian fish assemblages. Rather, fish assemblages varied largely both inshore and offshore, which dynamics overruled any effects of the artificially elevated temperature. Our study highlights the importance of the assessment of hydrogeomorphological variability of rivers and their influence on fish assemblage variability when examining spatial effects of thermal pollution