Nitrogenase Activity (Acetylene Reduction) of an Iron-Oxidizing Leptospirillum Strain Cultured as a Pioneer Microbe from a Recent Volcanic Deposit on Miyake-Jima, Japan
Nitrogenase Activity (Acetylene Reduction) of an Iron-Oxidizing Leptospirillum Strain Cultured as a Pioneer Microbe from a Recent Volcanic Deposit on Miyake-Jima, Japan
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DOI：
10.1264/jsme2.me09139
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发表时间：
2009-01-01
影响因子：
2.2
通讯作者：
Ohta, Hiroyuki
中科院分区：
文献类型：
--
作者：
Sato, Yoshinori;Hosokawa, Ken;Ohta, Hiroyuki
已知钩端螺旋菌属在酸性矿山排水和生物浸滤系统中占主导地位。在本文中，我们描述了从日本三宅岛（Miyake-jima）的酸性火山灰沉积物中分离出与氧化亚铁钩端螺旋菌密切相关的铁氧化细菌。我们进一步显示了其中一种分离株（菌株 C2-1）的固氮酶活性（乙炔还原）。该沉积物中含有 1.2 x 10(8) 总直接计数（g 干重）(-1) 和 7.1 x 10(5)（最可能数，MPN）（g 干重）(-1) 铁氧化剂。使用钩端螺旋菌 HH 培养基（pH 1.8）进行二价铁限制、需氧恒化培养，以选择和分离钩端螺旋菌组。根据含 Fe2+ 硅胶平板上均匀的菌落形态以及在 100 倍稀释的营养肉汤平板上不生长的情况，将 9 个分离株视为纯培养物。进一步检查的 6 个菌株的 16S rRNA 基因序列彼此具有 99.9-100% 的同一性。基于同源性的搜索表明所有菌株都属于氧化亚铁钩端螺旋菌分支。菌株C2-1在不含硫酸铵的钩端螺旋菌HH培养基（pH 1.8）中生长，显示乙炔初始还原率为58 mu mol h(-1)（g细胞碳）(-1)。
The genus Leptospirillum is known to dominate acid mine drainage and bioleaching systems. In this paper, we describe the isolation of iron-oxidizing bacteria closely related to Leptospirillum ferrooxidans from an acidic volcanic ash deposit on the island of Miyake (Miyake-jima), Japan. We further show the nitrogenase activity (acetylene reduction) for one (strain C2-1) of the isolates. The deposit harbored 1.2 x 10(8) total direct count (g dry weight)(-1) and 7.1 x 10(5) (most-probable-number, MPN) (g dry weight)(-1) of iron-oxidizer. A ferrous iron-limited, aerobic chemostat culture using Leptospirillum HH medium (pH 1.8) was performed to select and isolate the Leptospirillum group. Nine isolates were regarded as pure cultures based on uniform colony morphology on Fe2+-containing silica gel plates and absence of growth on 100-fold diluted nutrient broth plates. Six strains examined further shared 99.9-100% identity in 16S rRNA gene sequence with each other. Homology-based searches showed that all of the strains belonged to the Leptospirillum ferrooxidans clade. Strain C2-1 grown in ammonium sulfate-free Leptospirillum HH medium (pH 1.8) showed an initial rate of acetylene reduction of 58 mu mol h(-1) (g cell carbon)(-1).