Improved isolation strategies allowed the phenotypic differentiation of two Nitrospira strains from widespread phylogenetic lineages

Boris Nowka, Sandra Off, Holger Daims, Eva Spieck

    Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

    Abstract

    The second step of nitrification, the oxidation of nitrite to nitrate, is vital for the functioning of the nitrogen cycle, but our understanding of the ecological roles of the involved microorganisms is still limited. The known diversity of Nitrospira, the most widely distributed nitrite-oxidizing bacteria, has increased remarkably by analyses of 16S rRNA and functional gene sequences. However, only few representatives could be brought into laboratory cultures so far. In this study, two Nitrospira from activated sludge were isolated using novel approaches together with established methods. Highly enriched 'Candidatus Nitrospira defluvii' was separated from concomitant heterotrophs by taking advantage of its resistance against ampicillin and acriflavine. Beside this member of lineage I, a novel species of lineage II, named N. lenta, was initially enriched at 10°C and finally purified by using optical tweezers. The tolerance to elevated nitrite levels was much higher in N. defluvii than in the more fastidious N. lenta and was accompanied by pronounced biofilm formation. Phylogenetic classification of 12 additional enrichments indicated that Nitrospira lineage I is common in extreme and moderate ecosystems like lineage II. The new cultures will help to explore physiological and genomic differences affecting niche separation between members of this highly diverse genus.

    OriginalspracheEnglisch
    Aufsatznummerfiu031
    Seitenumfang11
    FachzeitschriftFEMS microbiology ecology
    Jahrgang91
    Ausgabenummer3
    DOIs
    PublikationsstatusVeröffentlicht - März 2015

    ÖFOS 2012

    • 106022 Mikrobiologie

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