title: In situ growth of the novel SM1 euryarchaeon from a string-of-pearls-like microbial community in its cold biotope, its physical separation and insights into its structure and physiology.
abstract: Recently, a unique archaeal/bacterial community that grows in a macroscopically visible string-of-pearls-like structure in cold (~10 degrees C), sulfurous marsh water was discovered. Here, a new technique is described that allows the fast and reliable growth of these string-of-pearls-like microbial communities in larger quantities on polyethylene nets in nature. The microbial net population, estimated to consist of about 10,000 single pearls, can be harvested once a week and the archaeal cells selectively separated by density gradient centrifugation. As in native pearls, the archaeal cell fraction obtained consisted of a single type of coccoid cells only, 0.6 micro m in diameter. This novel type of euryarchaea has been tentatively named SM1 euryarchaeon. Electron microscopy and immuno-fluorescence in situ hybridization (immuno-FISH) revealed that about 100 pili-like fibers, up to 3 micro m in length, emanate radially from the surface of each cell. The SM1 euryarchaeal cells exhibited a viability of about 90%. The optimal conditions for viability were temperatures between -2 degrees C and 20 degrees C, pH 5-9, and low salt conditions; cell viability was independent of oxygen partial pressures. The cultures stained gram-positive, the cell wall was sensitive to SDS, EDTA and Proteinase K treatment. The cells did not exhibit the typical fluorescence for methanogens and did not contain coenzyme F(420). The G+C-content was 34.5 mol%.
authors.affiliation: Lehrstuhl für Mikrobiologie und Archaeenzentrum, Universität Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Moissl
authors.forename: Christian
authors.initials: C
authors.lastname: Rudolph
authors.forename: Reinhard
authors.initials: R
authors.lastname: Rachel
authors.forename: Marcus
authors.initials: M
authors.lastname: Koch
authors.forename: Robert
authors.initials: R
authors.lastname: Huber
mesh_terms: D001105:Archaea / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure*; D001419:Bacteria / Q000254:growth & development; D002499:Centrifugation, Density Gradient; D003080:Cold Temperature; D017753:Ecosystem; D005455:Fluorescent Antibody Technique; D005618:Fresh Water / Q000382:microbiology*; D017404:In Situ Hybridization, Fluorescence; D008828:Microbiological Techniques; D015345:Oligonucleotide Probes; D020959:Polyethylene; D013455:Sulfur
chemical_list: D015345:Oligonucleotide Probes; D013455:Sulfur; D020959:Polyethylene