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The Nevskia project
Nevskia stained with toluidine blue showing the dichotomous slime stalks Abstract During the last hundred years, the neuston bacterium Nevskia ramosa has been described several times. This bacterium forms rosette-like conspicuous microcolonies at the air-water interface, which consist of dichotomously branched slime stalks with a single cell at each the tip. In this study, for the first time pure cultures of Nevskia ramosa were obtained from a bog lake (strain Soe1, DSMZ 11499) and a freshwater ditch (strain OL1, DSMZ 11500). The isolates showed special adaptations to life in the epineuston. They formed hydrophobic surface films of dull appearance. A slight bend forces the cells into a horizontal position. N. ramosa was sensitive to UV radiation, but revealed a very effective photorepair mechanism. Exposure to light of 350 nm after UV treatment raised the number of surviving cells by seven orders of magnitude, while with Escherichia coli only two orders were found. The isolates grew with a broad range of organic substrates. Surface films were formed only in the absence of combined nitrogen, however, nitrogenase activity was not detected. It appears that during growth at the air-water interface the cells benefit from trapping ammonia from the air. The G + C content of the DNA was 67.8 and 69.0 mol% for strain Soe1 and OL1, respectively. The slight difference was confirmed by ERIC-PCR. The 16 S rRNA sequences revealed 99.0 % similarity. Thus, both isolates represent two strains of the same species. The phylogenetic analysis indicated that Nevskia is a member of the proteobacteria that has no close relatives known so far. A classification within the g -group was based on relatively low bootstrap values.
Team members involved Heike Stürmeyer Teresa Pladdies Jörg Overmann Heribert Cypionka Cooperation Rudolf Amann, MPI Marine Mikrobiologie, Bremen Hans-Dietrich Babenzien, IGB Berlin/Neuglobsow Frank-Oliver Glöckner, MPI Marine Mikrobiologie, Bremen Publications Pladdies T, Babenzien H-D, Cypionka H (2004) Distribution of Nevskia ramosa and other rosette-forming neustonic bacteria. Microb Ecol 47:218-223 Stürmeyer H, Overmann J, Babenzien HD, Cypionka H (1998) Ecophysiological and phylogenetic studies of Nevskia ramosa in pure culture. Appl Environ Microbiol 64:1890-1894 Ottenjann T (1998) Vergleich von Rosetten-bildenden Bakterien asus dem Neuston verschiedener Gewässer. Diplom-Arbeit, Univ. Oldenburg Stürmeyer H (1997) Isolierung und mikrobiologische Charakterisierung von Nevskia ramosa. Diplomarbeit, Univ. Oldenburg Glöckner FO, Babenzien HD, Amann R (1998) Phylogeny and identification in situ of Nevskia ramosa. Appl Environ Microbiol 64:1895-1901 |
