title: Population profiles of a stable, commensalistic bacterial culture grown with toluene under sulphate-reducing conditions.
abstract: BACKGROUND
  Most bacteria present in nature are not culturable in pure culture by means of classic cultivation methods (Pace NR, 1997, Science 276:734-740; Amann RI et al., 1995, Microbiol Rev 59:143-169.). However, it was recently shown that most aerobic heterotrophic bacteria could grow only on artificial media when other micro-organisms are present (Kaeberlein T et al., 2002, Science 296:1127-1129). Because the sulphate reducer Desulfobacula toluolica DSM 7467 and a bacterium (strain MV1) identified as Cellulosimicrobium sp. were not culturable unaccompanied, flow cytometry was used to highlight the strains' relation within the consortium.
  
  
  METHODS
  DNA patterns were used to provide strain-specific information about population proliferation dynamics. Cells were grown anaerobically and fed with toluene under sulphate-reducing conditions.
  
  
  RESULTS
  Oxidation of toluene occurred only in association with sulphate reduction and growth of D. toluolica. A characteristic chromosomal pattern, with at least six subpopulations of D. toluolica, appeared during the stationary phase, and asymmetric cell division was detected. The accompanying strain MV1 grew repeatedly to a high percentage of the culture only in certain growth phases of D. toluolica independently of the feeding substrate toluene.
  
  
  CONCLUSIONS
  A commensalistic relation between the two strains is suggested. The repeated rapid and frequent changes of the quantities within the community subsets are indicative of very flexible adaptations to changing environmental conditions, reflecting the need for modulated cell states and the ability to use every available source of carbon and energy for survival.
authors: Department of Environmental Microbiology, Centre for Environmental Research Leipzig-Halle, Leipzig, Germany.
authors: Carsten
authors: C
authors: Vogt
authors: Andreas
authors: A
authors: Lösche
authors: Sabine
authors: S
authors: Kleinsteuber
authors: Susann
authors: S
authors: Müller
mesh_terms: D000192:Actinomycetales / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D015373:Bacterial Typing Techniques; D002469:Cell Separation; D003470:Culture Media; D004269:DNA, Bacterial / Q000032:analysis*; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D007211:Indoles; D008858:Microscopy, Phase-Contrast; D012336:RNA, Ribosomal, 16S / Q000032:analysis / Q000235:genetics; D013045:Species Specificity; D013194:Staining and Labeling; D013431:Sulfates / Q000378:metabolism; D016999:Sulfur-Reducing Bacteria / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D013559:Symbiosis; D013997:Time Factors; D014050:Toluene / Q000378:metabolism
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D005456:Fluorescent Dyes; D007211:Indoles; D012336:RNA, Ribosomal, 16S; D013431:Sulfates; D014050:Toluene; C007293:DAPI