A novel method for culturing of Leptothrix sp. strain OUMS1 in natural conditions

Tomoko Suzuki, Hiromichi Ishihara, Mitsuaki Furutani, Tomonori Shiraishi, Hitoshi Kunoh, Jun Takada

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Although some strains of Leptothrix spp. isolated from aquatic environments have been characterized by culturing them in laboratory conditions, they often show morphological and chemical features distinct from those found in natural environments. To resolve this discrepancy, a novel cultivation method was devised for culturing such strains in natural groundwater. Leptothrix sp. strain OUMS1 was pre-cultured in a medium lacking Fe for 2 days, and then injected into a small dialysis tube bag and immersed in a container with continuously flowing groundwater for 1–3 and 14 days. Microscopic analysis of the initial phase of sheath formation and arbitrary comparisons with medium cultures revealed that in groundwater the surface coat of the sheath comprised much thinner fibrils, and an inner sheath wall that was much thinner and more indistinct compared with medium cultures. These differences were probably attributable to poorer secretion from the cell surface in groundwater conditions. A nutrient-rich medium likely activates cell metabolism and promotes secretion, resulting in a thicker inner sheath wall and thicker outer coat fibrils. Aqueous-phase Fe was deposited on immature sheaths in a similar manner in both cultures. These results indicate that laboratory culture of isolated microbes does not always reflect their characteristics in natural environments.

Original languageEnglish
Pages (from-to)118-128
Number of pages11
Issue number2
Publication statusPublished - May 23 2012


  • Bacterial carbohydrates
  • Bacterial exudation
  • Deposition of aqueous-phase iron
  • Leptothrix sp. OUMS1
  • Novel culturing method in natural groundwater
  • Sheath formation

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Geology


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