Physiology of phototrophic iron(II)-oxidizing bacteria: implications for modern and ancient environments
Physiology of phototrophic iron(II)-oxidizing bacteria: implications for modern and ancient environments
复制标题
DOI：
10.1111/j.1574-6941.2008.00592.x
复制
发表时间：
2008-11-01
影响因子：
4.2
通讯作者：
Kappler, Andreas
中科院分区：
文献类型：
--
作者：
Hegler, Florian;Posth, Nicole R.;Kappler, Andreas
光合铁（II）[Fe（II）]氧化细菌存在于现代环境中，有证据表明这种代谢在早期地球上已经存在。我们确定了三个不同的光合作用的Fe（II）氧化菌株（紫色非硫细菌Rhodobacter ferrooxidans sp. strain SW 2，紫色硫细菌Thiodictyon sp. strain F4，和绿色硫细菌Chlorobium ferrooxidans strain KoFox）的Fe（II）氧化速率取决于pH、温度、光强和Fe（II）浓度。虽然我们发现菌株F4的Fe（II）氧化速率总体最高（4.5 mmol L（-1）天（-1），800 lux，20 ℃），但测定的最低光饱和值（发生最大Fe（II）氧化时）为菌株KoFox，光饱和度已低于50 lux。测定了R.铁氧化物菌株SW 2的Fe（II）浓度为32 pmol·h ~（-1）/细胞。在Fe（II）浓度高达30 mM时，没有观察到明显的毒性效应。30摄氏度。经鉴定，主要色素为类球蛋白、球蛋白酮、OH-球蛋白酮（SW 2）、视紫红质（F4）和氯杆菌素（KoFox）。这项研究将提高我们对现代环境中铁循环的生态生理学理解，并将有助于评估光养铁氧化剂是否可能有助于早期地球上Fe（III）的形成。
Phototrophic iron(II) [Fe(II)]-oxidizing bacteria are present in modern environments and evidence suggests that this metabolism was present already on early earth. We determined Fe(II) oxidation rates depending on pH, temperature, light intensity, and Fe(II) concentration for three phylogenetically different phototrophic Fe(II)-oxidizing strains (purple nonsulfur bacterium Rhodobacter ferrooxidans sp. strain SW2, purple sulfur bacterium Thiodictyon sp. strain F4, and green sulfur bacterium Chlorobium ferrooxidans strain KoFox). While we found the overall highest Fe(II) oxidation rates with strain F4 (4.5 mmol L(-1) day(-1), 800 lux, 20 degrees C), the lowest light saturation values [at which maximum Fe(II) oxidation occurred] were determined for strain KoFox with light saturation already below 50 lux. The oxidation rate per cell was determined for R. ferrooxidans strain SW2 to be 32 pmol Fe(II) h(-1) per cell. No significant toxic effect of Fe(II) was observed at Fe(II) concentrations of up to 30 mM. All three strains are mesophiles with upper temperature limits of c. 30 degrees C. The main pigments were identified to be spheroidene, spheroidenone, OH-spheroidenone (SW2), rhodopinal (F4), and chlorobactene (KoFox). This study will improve our ecophysiological understanding of iron cycling in modern environments and will help to evaluate whether phototrophic iron oxidizers may have contributed to the formation of Fe(III) on early earth.