title: Characteristics of cesium accumulation in the filamentous soil bacterium Streptomyces sp. K202.
abstract: A filamentous soil bacterium, strain K202, was isolated from soil where an edible mushroom (Boletopsis leucomelas) was growing and identified as belonging to the genus Streptomyces on the basis of its morphological characteristics and the presence of LL-2, 6-diaminopimelic acid. We studied the existence states of Cs and its migration from extracellular to intracellular fluid in the mycelia of Streptomyces sp. K202. The results indicated that Cs accumulated in the cells through at least 2 steps: in the first step, Cs(+) was immediately and non-specifically adsorbed on the negatively charged cell surface, and in the second step, this adsorbed Cs(+) was taken up into the cytoplasm, and a part of the Cs entering the cytoplasm was taken up by an energy-dependent transport system(s). Further, we confirmed that a part of the Cs(+) was taken up into the mycelia competitively with K(+), because K(+) uptake into the intact mycelia of the strain was significantly inhibited by the presence of Cs(+) in the culture media. This suggested that part of the Cs is transported by the potassium transport system. Moreover, (133)Cs-NMR spectra and SEM-EDX spectra of the mycelia that accumulated Cs showed the presence of at least 2 intracellular Cs states: Cs(+) trapped by intercellular materials such as polyphosphate and Cs(+) present in a cytoplasmic pool.
authors.affiliation: Chemistry Division, Kanagawa Prefectural Institute of Public Health, 1-3-1 Shimomachiya, Chigasaki-shi, Kanagawa, Japan. chika_kuwahara.u79v@pref.kanagawa.jp
authors.forename: Chikako
authors.initials: C
authors.lastname: Kuwahara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Fukumoto
authors.forename: Masami
authors.initials: M
authors.lastname: Nishina
authors.forename: Hideo
authors.initials: H
authors.lastname: Sugiyama
authors.forename: Yojiro
authors.initials: Y
authors.lastname: Anzai
authors.forename: Fumio
authors.initials: F
authors.lastname: Kato
mesh_terms: D001693:Biological Transport, Active / Q000502:physiology; D002586:Cesium / Q000032:analysis / Q000493:pharmacokinetics*; D002588:Cesium Radioisotopes / Q000032:analysis / Q000493:pharmacokinetics*; D002855:Chromatography, Thin Layer; D003960:Diaminopimelic Acid / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D011188:Potassium / Q000378:metabolism; D012989:Soil Pollutants / Q000032:analysis / Q000493:pharmacokinetics*; D013302:Streptomyces / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D002588:Cesium Radioisotopes; D012989:Soil Pollutants; D002586:Cesium; D003960:Diaminopimelic Acid; D011188:Potassium