Hall Justine R, Mitchell Kendra R, Jackson-Weaver Olan, Kooser Ara S, Cron Brandi R, Crossey Laura J, Takacs-Vesbach Cristina D
Department of Biology, University of New Mexico, 167 Castetter Hall, MSC03-2020 1, University of New Mexico, Albuquerque, NM 87131, USA.
Appl Environ Microbiol. 2008 Aug;74(15):4910-22. doi: 10.1128/AEM.00233-08. Epub 2008 Jun 6.
The diversity and distribution of a bacterial community from Coffee Pots Hot Spring, a thermal spring in Yellowstone National Park with a temperature range of 39.3 to 74.1 degrees C and pH range of 5.75 to 6.91, were investigated by sequencing cloned PCR products and quantitative PCR (qPCR) of 16S rRNA and metabolic genes. The spring was inhabited by three Aquificae genera--Thermocrinis, Hydrogenobaculum, and Sulfurihydrogenibium--and members of the Alpha-, Beta-, and Gammaproteobacteria, Firmicutes, Acidobacteria, Deinococcus-Thermus, and candidate division OP5. The in situ chemical affinities were calculated for 41 potential metabolic reactions using measured environmental parameters and a range of hydrogen and oxygen concentrations. Reactions that use oxygen, ferric iron, sulfur, and nitrate as electron acceptors were predicted to be the most energetically favorable, while reactions using sulfate were expected to be less favorable. Samples were screened for genes used in ammonia oxidation (amoA, bacterial gene only), the reductive tricarboxylic acid (rTCA) cycle (aclB), the Calvin cycle (cbbM), sulfate reduction (dsrAB), nitrogen fixation (nifH), nitrite reduction (nirK), and sulfide oxidation (soxEF1) by PCR. Genes for carbon fixation by the rTCA cycle and nitrogen fixation were detected. All aclB sequences were phylogenetically related and spatially correlated to Sulfurihydrogenibium 16S rRNA gene sequences using qPCR (R(2) = 0.99). This result supports the recent finding of citrate cleavage by enzymes other than ATP citrate lyase in the rTCA cycle of the Aquificaceae family. We briefly consider potential biochemical mechanisms that may allow Sulfurihydrogenibium and Thermocrinis to codominate some hydrothermal environments.
对黄石国家公园的咖啡壶温泉（温度范围为39.3至74.1摄氏度，pH范围为5.75至6.91）中的细菌群落多样性和分布进行了研究，采用对16S rRNA和代谢基因的克隆PCR产物进行测序以及定量PCR（qPCR）的方法。该温泉中栖息着三个产水菌属——嗜热栖热菌属、氢杆菌属和硫氢还原菌属——以及α-、β-和γ-变形菌纲、厚壁菌门、酸杆菌门、嗜热放线菌纲和候选分类群OP5的成员。利用测量的环境参数以及一系列氢气和氧气浓度，计算了41种潜在代谢反应的原位化学亲和力。预计以氧气、铁离子、硫和硝酸盐作为电子受体的反应在能量上最为有利，而以硫酸盐作为电子受体的反应则不太有利。通过PCR筛选样品中用于氨氧化（amoA，仅细菌基因）、还原性三羧酸（rTCA）循环（aclB）、卡尔文循环（cbbM）、硫酸盐还原（dsrAB）、固氮（nifH）、亚硝酸盐还原（nirK）和硫化物氧化（soxEF1）的基因。检测到了通过rTCA循环进行碳固定和固氮的基因。使用qPCR分析，所有aclB序列在系统发育上与硫氢还原菌16S rRNA基因序列相关且在空间上相关（R² = 0.99）。这一结果支持了最近在产水菌科rTCA循环中发现的除ATP柠檬酸裂解酶外其他酶进行柠檬酸裂解的发现。我们简要考虑了可能使硫氢还原菌属和嗜热栖热菌属在一些热液环境中共存的潜在生化机制。
