Use of Fe(III) as an electron acceptor to recover previously uncultured hyperthermophiles:: Isolation and characterization of Geothermobacterium ferrireducens gen. nov., sp nov.
Use of Fe(III) as an electron acceptor to recover previously uncultured hyperthermophiles:: Isolation and characterization of Geothermobacterium ferrireducens gen. nov., sp nov.
复制标题
DOI：
10.1128/aem.68.4.1735-1742.2002
复制
发表时间：
2002-04-01
影响因子：
4.4
通讯作者：
Lovley, DR
中科院分区：
文献类型：
--
作者：
Kashefi, K;Holmes, DE;Lovley, DR
最近已经认识到，使用Fe（III）作为末端电子受体的能力在超嗜热微生物中是高度保守的特征。这表明，它可能会恢复尚未培养的超嗜热菌在纯培养，如果Fe（HI）被用作电子受体。作为怀俄明州黄石国家公园黑曜石池地区微生物多样性研究的一部分，热沉积物样品用作在含有氢作为唯一电子供体和低结晶性氧化铁（III）作为电子受体的培养基中富集培养物的接种物。在固化的Fe（III）氧化物培养基上回收纯培养物。分离物，命名为FW-1a，是一种超嗜热厌氧菌，其生长完全通过将氢氧化与结晶不良的Fe（III）氧化物的还原偶联。有机碳不是生长所必需的。磁铁矿是在评价的培养条件下Fe（HI）氧化物还原的最终产物。细胞呈杆状，约0.5 μ m × 1.0 ~ 1.2 μ m，能动，有一根鞭毛。菌株FW-1a生长在中性pH、淡水盐度和65至100 ℃之间的温度下，最适温度为85至90 ℃。据我们所知，这是细菌中任何有机体的最高温度。菌株FW-1a的16 S核糖体DNA（rDNA）序列的分析将其置于细菌内，与丰富但未培养的微生物最密切相关，其16 S rDNA序列先前已从黑曜石池和冰岛的陆地温泉中回收。虽然先前的研究推断具有这些16 S rDNA序列的未培养微生物是硫酸盐还原生物，但不还原硫酸盐的菌株FW-1a的生理学表明这些生物体同样可能是Fe（III）还原剂。这些结果进一步表明，Fe（HI）可能有助于从热液环境中恢复尚未培养的微生物，并说明在仅从16 S rDNA序列推断至少一些嗜热微生物的生理特征时必须谨慎。根据其16 S rDNA序列和生理特性，菌株FW-1a代表细菌中的一个新属。铁还原地热杆菌Gen. nov.新种，（ATCC BAA-426）。
It has recently been recognized that the ability to use Fe(III) as a terminal electron acceptor is a highly conserved characteristic in hyperthermophilic microorganisms. This suggests that it may be possible to recover as-yet-uncultured hyperthermophiles in pure culture if Fe(HI) is used as an electron acceptor. As part of a study of the microbial diversity of the Obsidian Pool area in Yellowstone National Park, Wyo., hot sediment samples were used as the inoculum for enrichment cultures in media containing hydrogen as the sole electron donor and poorly crystalline Fe(III) oxide as the electron acceptor. A pure culture was recovered on solidified, Fe(III) oxide medium. The isolate, designated FW-1a, is a hyperthermophilic anaerobe that grows exclusively by coupling hydrogen oxidation to the reduction of poorly crystalline Fe(III) oxide. Organic carbon is not required for growth. Magnetite is the end product of Fe(HI) oxide reduction under the culture conditions evaluated. The cells are rod shaped, about 0.5 mum by 1.0 to 1.2 mum, and motile and have a single flagellum. Strain FW-1a grows at circumneutral pH, at freshwater salinities, and at temperatures of between 65 and 100degreesC with an optimum of 85 to 90degreesC. To our knowledge this is the highest temperature optimum of any organism in the Bacteria. Analysis of the 16S ribosomal DNA (rDNA) sequence of strain FW-1a places it within the Bacteria, most closely related to abundant but uncultured microorganisms whose 16S rDNA sequences have been previously recovered from Obsidian Pool and a terrestrial hot spring in Iceland. While previous studies inferred that the uncultured microorganisms with these 16S rDNA sequences were sulfate-reducing organisms, the physiology of the strain FW-1a, which does not reduce sulfate, indicates that these organisms are just as likely to be Fe(III) reducers. These results further demonstrate that Fe(HI) may be helpful for recovering as-yet-uncultured microorganisms from hydrothermal environments and illustrate that caution must be used in inferring the physiological characteristics of at least some thermophilic microorganisms solely from 16S rDNA sequences. Based on both its 16S rDNA sequence and physiological characteristics, strain FW-1a represents a new genus among the Bacteria. The name Geothermobacterium ferrireducens gen. nov., sp. nov., is proposed (ATCC BAA-426).