@article{oai:kanazawa-u.repo.nii.ac.jp:00010383,
 author = {佐藤, 一博 and 田崎, 和江},
 issue = {6},
 journal = {環境技術, Journal of Environmental Conservation Engineering},
 month = {Jan},
 note = {Iron bacteria precipitate copious amounts of iron hydroxides in microbial mats normally inhabiting in ironrich water. In this study, the following findings were made on accumulation of Fe and the formation of ironsheath regarding L. ochracea, an iron bacterium which is one of the most common inhabitants of iron microbial mats at neutral pH collected from underground water, by an electron microscopic observation: (1) In a field experiment, the rate of inorganic precipitation is 1.6, and the rate of precipitation involving iron bacteria is 8.4, so that iron oxidizing bacteria are precipitating iron hydroxides in an amount five times or more of the inorganic precipitates. (2) By metabolic pathway of live L. ochracea, the iron sheath can be formed in a short time period. (3) UV-C treatment destroys the iron bacterial cells, thereby inhibiting the formation of iron-microbial mats. (4) At an early formation stage of iron- sheath of L. ochracea, a fine fibrous network structure is formed around the cell wall. The tubular sheath is composed of thicken fibrous materials. (5) By the metabolism of the iron bacterium, the oxidized Fe3+ is accumulated in the fine fibrous polysaccharide, thereby forming a sheath made of a complex of iron and an organic substance. (6) The fine particles of iron hydroxide found on the surface of the sheath are particles of iron hydroxide oxidized inorganically. (7) The matured sheath fixes low-crystalline ferrihydrite minerals in microbial mats. 鉄成分に富む水中には, 鉄細菌が生息しており, 黄褐色のバイオマットを形成している.本研究では, 中性の地下水に生成した鉄のバイオマット中に一般的に生息する鉄細菌Leptothrix ochraceaについて, 電子顕微鏡観察から, 鉄の濃集と鞘の形成過程について, 以下の知見を得た. (1) 野外において, 鉄の無機的な沈殿率は1.6, 鉄細菌が関与する沈殿率は8.4であり, 鉄細菌は無機沈殿の5倍以上の鉄を沈殿させる. (2) 生きているL.ochraceaの代謝により短時間で鉄鞘が形成される. (3) UV-C処理を行うことで, 鉄細菌の細胞が死滅し, 鉄バイオマットの形成が抑制される. (4) L.ochyaceaの鞘形成の初期段階は, 菌体の周囲に網目状の繊維物質を形成する.繊維が太くなることでチューブ状の鞘が形成される. (5) 鉄細菌の代謝によって酸化されたFe3+が繊維状多糖類に蓄積し, 鉄と有機物の複合体からなる鞘を形成する. (6) 鞘表面に認められる水酸化鉄の微粒子は, 無機化学的に酸化された水酸化鉄の粒子である. (7) 成熟した鞘は低結晶性のFerrihydriteを形成する.},
 pages = {467--475},
 title = {中性pHに生息するLeptothrix ochraceaの鉄濃集作用},
 volume = {33},
 year = {2004}
}