An integrated approach for ecological, cultivational, ultrastructural, and genomic analysis of the uncultivated giant magnetotactic rod cand. "Magnetobacterium bavaricum"
Zusammenfassung der Projektergebnisse
Magnetotactic bacteria (MTB) are a diverse group of aquatic procaryotes whose swimming motility is directed by complex intracellular magnetic organelles, the magnetosomes, which are formed by controlled biomineralization. Despite of their ecological importance and abundance in many aquatic ecosystems, their biology has remained largely unknown, since most MTB from natural populations have resisted conventional attempts of isolation. In this study, we established and employed a set of methods for the comprehensive cultivation-independent chacterization of uncultivated MTB from various environments. Specifically, we used this for the characterization of the magnetotactic rod cand. “Magnetobacterium bavaricum” (Mbav), which is distinct from all other known MTB by its unique affiliation with the deep-branching Nitrospirae group, its intricate cell biology and large size, and its ability to biomineralize up to 1000 bulletshaped magnetite crystals. We used magnetic collection and targeted microsorting for unambigous correlation of ultrastructural, phylogenetic and genomic information from single cells. This lead to the discovery of structures as well as genes homologous to those known from magnetotactic Proteobacteria, suggesting a common ecolutionary link between them and the Nitrospirae-like Mbav. In addition, a large gene cluster representing a genomic “magnetosome island” was found to contain further unrelated genes of sofar unknown function, which are predicted to account for the observed peculiarities and structural intricacy of magnetosome biosynthesis in Mbav. Analysis of the nearly complete genome assembly enabled the metabolic reconstruction of the putative lifestyle of Mbav, which appears highly adapted to its chemically stratified habitats along redox gradients. This information will faciltate to identify the growth requirements of Mbav in future attempt to isolate and grow the bacterium in axenic lab culture.
Projektbezogene Publikationen (Auswahl)
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2010. Cultivation-independent characterization of "Candidatus Magnetobacterium bavaricum"; via ultrastructural, geochemical, ecological and metagenomic methods. Environ. Microbiol. 12(9):2466–2478
Jogler, C., M. Niebler, W. Lin, M. Kube, G. Wanner, S. Kolinko, P. Stief, A. Beck, D. DeBeer, N. Petersen, Y. Pan, R. Amann, R. Reinhardt, and D. Schüler
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2011. Conservation of proteobacterial magnetosome genes and structures in an uncultivated member of the deep-branching Nitrospirae phylum. Proc. Natl. Acad. Sci. USA 108(3):1134-1139
Jogler, C., G. Wanner, S. Kolinko, M. Niebler, R. Amann, N. Petersen, M. Kube, R. Reinhardt, and D. Schüler
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2011. Metagenomic analysis reveals unexpected subgenomic diversity of magnetotactic bacteria within the phylum Nitrospirae. Appl. Environ. Microbiol. 77(1):323-326
Lin, W., C. Jogler, D. Schüler, and Y. Pan
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2012. Single-cell analysis reveals a novel uncultivated magnetotactic bacterium within the candidate division OP3. Environ. Microbiol. 14(7):1709-1721
Kolinko, S., C. Jogler, E. Katzmann, G. Wanner, J. Peplies, and D. Schüler
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2013. Clone libraries and single cell genome amplification reveal extended diversity of uncultivated magnetotactic bacteria from marine and freshwater environments. Environ. Microbiol. 15(5):1290-1301
Kolinko, S., G. Wanner, E. Katzmann, F. Kiemer, B. Fuchs, and D. Schüler
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2014. Single-cell genomics reveals potential for magnetite and greigite biomineralization in an uncultivated multicellular magnetotactic prokaryote. Environ. Microbiol. Rep., Vol 6 Issue 5, Special Issue: Microbes, metals and metalloids, October 2014, Pages 524-531
Kolinko, S., M. Richter, F.-O. Glöckner, A. Brachmann, and D. Schüler
