caa a22 4500 467911878 CHVBK 20180406152851.0 cr unu---uuuuu 170328e20060801xx s 000 0 eng 10.1007/s11157-006-9105-0 doi (NATIONALLICENCE)springer-10.1007/s11157-006-9105-0 Ecology and molecular adaptations of the halophilic black yeast Hortaea werneckii [Elektronische Daten] [Nina Gunde-Cimerman, Ana Plemenitaš] Molecular studies on halophilic adaptations have focused on prokaryotic microorganisms due to a lack of known appropriate eukaryotic halophilic microorganisms. However, the black yeast Hortaea werneckii has been identified as the dominant fungal species in hypersaline waters on three continents. It represents a new model organism for studying the mechanisms of salt tolerance in eukaryotes. Ultrastructural studies of the H. werneckii cell wall have shown that it synthesizes dihydroxynaphthalene (DHN) melanin under both saline and non-saline growth conditions. However, melanin granules in the cell walls are organized in a salt-dependent way, implying the potential osmoprotectant role of melanin. At the level of membrane structure, H. werneckii maintains a sterol-to-phospholipid ratio significantly lower than the salt-sensitive Saccharomyces cerevisiae. Accordingly, membranes of H. werneckii are more fluid over a wide range of NaCl concentrations, indicating high intrinsic salt stress tolerance. Even H. werneckii grown in high NaCl concentrations maintains very low intracellular amounts of potassium and sodium, demonstrating the sodium-excluder character of this organism. The salt-dependent expressions of two HwENA genes suggest roles for them in the adaptation to changing salt concentrations. The high similarity of these ENA ATPases to other fungal ENA ATPases involved in Na+/K+ transport indicates their potential importance in H. werneckii ion homeostasis. Glycerol is the main compatible solute which accumulates in the cytoplasm of H. werneckii at high salinity, although it seems that mycosporines may also act as supplementary compatible solutes. Salt dependent increase in glycerol synthesis is supported by the identification of two copies of a gene putatively coding for glycerol-3-phosphate-dehydrogenase. Expression of only one of these genes is salt dependent. Springer Science+Business Media B.V., 2006 Compatible solutes nationallicence Ecology nationallicence Halophiles nationallicence Hortaea werneckii nationallicence Hypersaline water nationallicence Ions nationallicence Melanin nationallicence Membrane nationallicence Mycosporines nationallicence Salterns nationallicence Gunde-Cimerman Nina Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna POT 111, 1000, Ljubljana, Slovenia aut Plemenitaš Ana Faculty of Medicine, Institute of Biochemistry, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia aut Reviews in Environmental Science and Bio/Technology Kluwer Academic Publishers 5/2-3(2006-08-01), 323-331 1569-1705 5:2-3<323 2006 5 11157 https://doi.org/10.1007/s11157-006-9105-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11157-006-9105-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gunde-Cimerman Nina Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna POT 111, 1000, Ljubljana, Slovenia aut NATIONALLICENCE 700 1- Plemenitaš Ana Faculty of Medicine, Institute of Biochemistry, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia aut NATIONALLICENCE 773 0- Reviews in Environmental Science and Bio/Technology Kluwer Academic Publishers 5/2-3(2006-08-01), 323-331 1569-1705 5:2-3<323 2006 5 11157 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer