1887

Abstract

Heckmann and Schmidt described the genus for bacterial endosymbionts of freshwater ciliates affiliated with the genus , and the species for obligate endosymbionts living in the cytoplasm of . Pure cultures of the type strain could not be established due to the obligate nature of the symbiotic relationship between the endosymbionts and their hosts. Therefore, is one of a few bacterial species with validly published names that lack a deposited pure culture. Meanwhile, it was demonstrated that the endosymbionts used for the description of the type of are closely related to obligately free-living strains. Similarity values of the 16S rRNA gene sequences obtained from the endosymbionts in the ciliate culture and free-living isolates in the range 99.1–99.4 % indicate that these organisms belong to the same species. Here, we have emended the description of by characterization of free-living strains maintained as pure cultures. The species was characterized as having low G+C contents of the DNA (44–46 mol%), small genome sizes (1.5–2.5 Mbp) and a lack of motility. Because of distinct differences in lifestyle and the genome size of strains, we propose that two novel subspecies should be established, subsp. subsp. nov. [with a type, which is a description based on endosymbionts in the culture ‘stock 15’ of the ciliate (ATCC 30859)] and subsp. subsp. nov. [with the type strain QLW-P1DMWA-1 (=DSM 18221=CIP 109841)], for the obligate endosymbionts of and and obligately free-living strains, respectively.

Loading

Article metrics loading...

/content/journal/ijsem/10.1099/ijs.0.005801-0
2009-08-01
2019-10-14
Loading full text...

Full text loading...

/deliver/fulltext/ijsem/59/8/2002.html?itemId=/content/journal/ijsem/10.1099/ijs.0.005801-0&mimeType=html&fmt=ahah

References

  1. Bahr, M., Hobbie, J. E. & Sogin, M. L. ( 1996; ). Bacterial diversity in an arctic lake: a freshwater SAR11 cluster. Aquat Microb Ecol 11, 271–277.[CrossRef]
    [Google Scholar]
  2. Crump, B. C., Armbrust, E. V. & Baross, J. A. ( 1999; ). Phylogenetic analysis of particle-attached and free-living bacterial communities in the Columbia River, its estuary, and the adjacent coastal ocean. Appl Environ Microbiol 65, 3192–3204.
    [Google Scholar]
  3. Fauré-Fremiet, E. ( 1952; ). Symbiontes bactériens des ciliés du genre Euplotes. C R Acad Sci 235, 402–403 (in French).
    [Google Scholar]
  4. Foissner, W. ( 1978; ). Euplotes moebiusi f. quadricirratus (Ciliophora, Hypotrichia) II. Die Feinstruktur einiger cytoplasmatischer Organellen. Naturk Jahresb Stadt Linz 23, 17–24 (in German).
    [Google Scholar]
  5. Fujishima, M. & Heckmann, K. ( 1984; ). Intra-and interspecies transfer of endosymbionts in Euplotes. J Exp Zool 230, 339–345.[CrossRef]
    [Google Scholar]
  6. Hahn, M. W. ( 2003; ). Isolation of strains belonging to the cosmopolitan Polynucleobacter necessarius cluster from freshwater habitats located in three climatic zones. Appl Environ Microbiol 69, 5248–5254.[CrossRef]
    [Google Scholar]
  7. Hahn, M. W. & Höfle, M. G. ( 2001; ). Grazing of protozoa and its effect on populations of aquatic bacteria. FEMS Microbiol Ecol 35, 113–121.[CrossRef]
    [Google Scholar]
  8. Hahn, M. W., Stadler, P., Wu, Q. L. & Pöckl, M. ( 2004; ). The filtration-acclimatization-method for isolation of an important fraction of the not readily cultivable bacteria. J Microbiol Methods 57, 379–390.[CrossRef]
    [Google Scholar]
  9. Hahn, M. W., Pöckl, M. & Wu, Q. L. ( 2005; ). Low intraspecific diversity in a Polynucleobacter subcluster population numerically dominating bacterioplankton of a freshwater pond. Appl Environ Microbiol 71, 4539–4547.[CrossRef]
    [Google Scholar]
  10. Heckmann, K. ( 1975; ). Omikron, ein essentieller Endosymbiont von Euplotes aediculatus. J Protozool 22, 97–104 (in German).[CrossRef]
    [Google Scholar]
  11. Heckmann, K. & Schmidt, H. J. ( 1987; ). Polynucleobacter necessarius gen. nov., sp. nov., an obligately endosymbiotic bacterium living in the cytoplasm of Euplotes aediculatus. Int J Syst Bacteriol 37, 456–457.[CrossRef]
    [Google Scholar]
  12. Heckmann, K., ten Hagen, R. & Görtz, H.-D. ( 1983; ). Freshwater Euplotes species with a 9 type 1 cirrus pattern depend upon endosymbionts. J Protozool 30, 284–289.[CrossRef]
    [Google Scholar]
  13. Hiorns, W. D., Methé, E. A., Nierzwickibauer, S. A. & Zehr, J. P. ( 1997; ). Bacterial diversity in Adirondack mountain lakes as revealed by 16S rRNA gene sequences. Appl Environ Microbiol 63, 2957–2960.
    [Google Scholar]
  14. Petroni, G., Dini, F., Verni, F. & Rosati, G. ( 2002; ). A molecular approach to the tangled intrageneric relationships underlying phylogeny in Euplotes (Ciliophora, Spirotrichea). Mol Phylogenet Evol 22, 118–130.[CrossRef]
    [Google Scholar]
  15. Schmidt, H. J. ( 1982; ). Isolation of omikron-endosymbionts from mass cultures of Euplotes aediculatus and characterization of their DNA. Exp Cell Res 140, 417–425.[CrossRef]
    [Google Scholar]
  16. Springer, N., Amann, R., Ludwig, W., Schleifer, K. H. & Schmidt, H. J. ( 1996; ). Polynucleobacter necessarius, an obligate bacterial endosymbiont of the hypotrichous ciliate Euplotes aediculatus, is a member of the beta-subclass of Proteobacteria. FEMS Microbiol Lett 135, 333–336.
    [Google Scholar]
  17. Stackebrandt, E. & Ebers, J. ( 2006; ). Taxonomic parameters revisited: tarnished gold standards. Microbiol Today 33, 152–155.
    [Google Scholar]
  18. Stamatakis, A., Hoover, P. & Rougemont, J. ( 2008; ). A rapid bootstrap algorithm for the RAxML web-servers. Syst Biol 57, 758–771.[CrossRef]
    [Google Scholar]
  19. Tamura, K., Dudley, J., Nei, M. & Kumar, S. ( 2007; ). mega4: Molecular Evolutionary Genetics Analysis (mega) software version 4.0. Mol Biol Evol 24, 1596–1599.[CrossRef]
    [Google Scholar]
  20. Tóth, E. M., Kéki, Z., Homonnay, Z. G., Borsodi, A. K., Márialigeti, K. & Schumann, P. ( 2008; ). Nocardioides daphniae sp. nov., isolated from Daphnia cucullata (Crustacea: Cladocera). Int J Syst Evol Microbiol 58, 78–83.[CrossRef]
    [Google Scholar]
  21. Vannini, C., Petroni, G., Verni, F. & Rosati, G. ( 2005; ). Polynucleobacter bacteria in the brackish-water species Euplotes harpa (Ciliata, Hypotrichia). J Eukaryot Microbiol 52, 116–122.[CrossRef]
    [Google Scholar]
  22. Vannini, C., Pöckl, M., Petroni, G., Wu, Q. L., Lang, E., Stackebrandt, E., Schrallhammer, M., Richardson, P. M. & Hahn, M. W. ( 2007; ). Endosymbiosis in statu nascendi: close phylogenetic relationship between obligately endosymbiotic and obligately free-living Polynucleobacter strains (Betaproteobacteria). Environ Microbiol 9, 347–359.[CrossRef]
    [Google Scholar]
  23. Wu, Q. L. & Hahn, M. W. ( 2006a; ). Differences in structure and dynamics of Polynucleobacter communities in a temperate and a subtropical lake revealed at three phylogenetic levels. FEMS Microbiol Ecol 57, 67–79.[CrossRef]
    [Google Scholar]
  24. Wu, Q. L. & Hahn, M. W. ( 2006b; ). High predictability of the seasonal dynamics of a species-like Polynucleobacter population in a freshwater lake. Environ Microbiol 8, 1660–1668.[CrossRef]
    [Google Scholar]
  25. Wu, Q. L., Schauer, M., Kamst-Van Agterveld, M. P., Zwart, G. & Hahn, M. W. ( 2006; ). Bacterioplankton community composition along a salinity gradient of sixteen high-mountain lakes located on the Tibetan Plateau, China. Appl Environ Microbiol 72, 5478–5485.[CrossRef]
    [Google Scholar]
  26. Zwart, G., Crump, B. C., Kamst-van Agterveld, M. P., Hagen, F. & Han, S.-K. ( 2002; ). Typical freshwater bacteria: an analysis of available 16S rRNA gene sequences from plankton of lakes and rivers. Aquat Microb Ecol 28, 141–155.[CrossRef]
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/ijsem/10.1099/ijs.0.005801-0
Loading
/content/journal/ijsem/10.1099/ijs.0.005801-0
Loading

Data & Media loading...

Images of colonies formed by a pure culture of a free-lining strain. [PDF](52 KB)

PDF

Graph showing the maximum optical density in NSY medium of the strains described, related free-living strains and the type strains of four other species affiliated with the family . [PDF](36 KB)

PDF

Habitats from which the free-living strains investigated were isolated. [PDF](54 KB)

PDF

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error