Initial Assemblage of Bacterial Saccharic Fibrils and Element Deposition to Form an Immature Sheath in Cultured Leptothrix sp. Strain OUMS1

Minerals

Mitsuaki Furutani¹  Tomoko Suzuki¹  Hiromichi Ishihara¹  Hideki Hashimoto¹  Hitoshi Kunoh¹ 

[1] Department of Material Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan;

关键词: Leptothrix;    iron-oxidizing bacterium;    inorganic/organic complex;    bacterial saccharic fibril;    initial formation of Leptothrix sheath;   

DOI  :  10.3390/min1010157

来源: mdpi

【 摘 要 】

In an aquatic environment, the genus Leptothrix produces an extracellular Fe- or Mn-encrusted tubular sheath composed of a complex hybrid of bacterial exopolymers and aqueous-phase inorganic elements. This ultrastructural study investigated initial assemblage of bacterial saccharic fibrils and subsequent deposition of aqueous-phase inorganic elements to form the immature sheath skeleton of cultured Leptothrix sp. strain OUMS1. After one day of culture, a globular and/or thread-like secretion was observed on the surface of the bacterial cell envelope, and secreted bodies were transported across the intervening space away from the cell to form an immature sheath skeleton comprising assembled and intermingled fibrils. Energy dispersive X-ray microanalysis and specific Bi-staining detected a distinguishable level of P, trace Si, and a notable amount of carbohydrates in the skeleton, but not Fe. By the second day, the skeleton was prominently thickened with an inner layer of almost parallel aligned fibrils, along with low level of Fe deposition, whereas an outer intermingled fibrous layer exhibited heavy deposition of Fe along with significant deposition of P and Si. These results indicate that basic sheath-construction proceeds in two steps under culture conditions: an initial assemblage of bacterial saccharic fibrils originated from the cell envelope and the subsequent deposition of aqueous-phase Fe, P, and Si.

【 授权许可】

CC BY   
© 2011 by the authors; licensee MDPI, Basel, Switzerland.