Browsing by Author "Steinová, Jana"

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    Microbially influenced corrosion of carbon steel in the presence of anaerobic sulphate-reducing bacteria
    (TAYLOR & FRANCIS LTD, 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND, 2019-01-01) Černoušek, Tomáš; Shrestha, Rojina; Kovářová, Hana; Špánek, Roman; Ševců, Alena; Sihelská, Kristína; Kokinda, Jakub; Stoulil, Jan; Steinová, Jana
    Carbon steel is currently being considered as a candidate canister material for use in a deep geological repository of radioactive waste. Assessment of canister material corrosion through microbial activity is an important part of the safety assessment for the final repository. The aim of study was to compare and characterise the corrosion behaviour of carbon steel under sterile and non-sterile anaerobic conditions in natural groundwater containing sulphate-reducing bacteria (SRB). A molecular-biological approach was used to determine the presence and abundance changes of relevant bacterial groups. Carbon steel corrosion rates were higher in the presence of SRB compared with sterile control. EIS described the evolution of three time-constants under non-sterile conditions, while scanning electron microscopy confirmed that the carbon steel surface was covered with a two-layer biofilm. Molecular-biological analysis of the water and biofilm indicated the dominance of SRB, with Desulfomicrobium and Desulfovibrio species prevalent.
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    Reproductive and dispersal strategies shape the diversity of mycobiont-photobiont association in Cladonia lichens
    (2019-05-01) Steinová, Jana; Škaloud, Pavel; Yahr, Rebecca; Bestová, Helena; Muggia, Lucia
    Ecological preferences, partner compatibility, or partner availability are known to be important factors shaping obligate and intimate lichen symbioses. We considered a complex of Cladonia species, traditionally differentiated by the extent of sexual reproduction and the type of vegetative propagules, to assess if the reproductive and dispersal strategies affect mycobiont-photobiont association patterns. In total 85 lichen thalli from 72 European localities were studied, two genetic markers for both Cladonia mycobionts and Asterochloris photobionts were analyzed. Variance partitioning analysis by multiple regression on distance matrices was performed to describe and partition variance in photobiont genetic diversity. Asexually reproducing Cladonia in our study were found to be strongly specific to their photobionts, associating with only two closely related Asterochloris species. In contrast, sexually reproducing lichens associated with seven unrelated Asterochloris lineages, thus being photobiont generalists. The reproductive mode had the largest explanatory power, explaining 44% of the total photobiont variability. Reproductive and dispersal strategies are the key factors shaping photobiont diversity in this group of Cladonia lichens. A strict photobiont specialisation observed in two studied species may steer both evolutionary flexibility and responses to ecological changes of these organisms, and considerably limit their distribution ranges.