Connecting the dots: linking nitrogen cycle gene expression to nitrogen fluxes in marine sediment mesocosms.
Connecting the dots: linking nitrogen cycle gene expression to nitrogen fluxes in marine sediment mesocosms.
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DOI：
10.3389/fmicb.2014.00429
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发表时间：
2014
影响因子：
5.2
通讯作者：
Ward BB
中科院分区：
文献类型：
--
作者：
Bowen JL;Babbin AR;Kearns PJ;Ward BB
将分子信息直接与微生物转化率联系起来仍然是一个挑战，尽管分子方法可以用来研究微生物的生物地球化学。通过将关键基因的基因丰度和表达信息与氮通量的定量建模相结合，我们可以开始理解遗传信号变化的尺度以及它们与关键功能的关系。我们使用定量PCR的DNA和cDNA，沿着与生物地球化学建模，以评估如何丰富和表达的微生物负责氮循环中的两个步骤随着时间的推移在河口沉积物中围隔生态系统。从沿海马萨诸塞州收集沉积物和水，并在重复的20 L围隔生态系统中维持45天。所有主要的无机氮物种的浓度进行了测量，每天和用于从基于蒙特卡洛的非负最小二乘分析的有限差分方程推导硝化和反硝化速率。围隔遵循一个经典的再生序列，其中从有机物分解释放的铵随后被氧化为亚硝酸盐，然后进一步氧化为硝酸盐，其中一部分最终被还原。氨氧化古菌氨单加氧酶（amoA）成绩单的归一化丰度密切跟踪整个实验中的氨氧化速率。没有这样的关系，但是，是明显的反硝化速率和归一化丰度的亚硝酸盐还原酶（nirS和nirK）成绩单之间。这些发现强调了将微生物群落的结构与生物地球化学过程的速率直接联系起来的复杂性。
Connecting molecular information directly to microbial transformation rates remains a challenge, despite the availability of molecular methods to investigate microbial biogeochemistry. By combining information on gene abundance and expression for key genes with quantitative modeling of nitrogen fluxes, we can begin to understand the scales on which genetic signals vary and how they relate to key functions. We used quantitative PCR of DNA and cDNA, along with biogeochemical modeling to assess how the abundance and expression of microbes responsible for two steps in the nitrogen cycle changed over time in estuarine sediment mesocosms. Sediments and water were collected from coastal Massachusetts and maintained in replicated 20 L mesocosms for 45 days. Concentrations of all major inorganic nitrogen species were measured daily and used to derive rates of nitrification and denitrification from a Monte Carlo-based non-negative least-squares analysis of finite difference equations. The mesocosms followed a classic regeneration sequence in which ammonium released from the decomposition of organic matter was subsequently oxidized to nitrite and then further to nitrate, some portion of which was ultimately denitrified. Normalized abundances of ammonia oxidizing archaeal ammonia monoxoygenase (amoA) transcripts closely tracked rates of ammonia oxidation throughout the experiment. No such relationship, however, was evident between denitrification rates and the normalized abundance of nitrite reductase (nirS and nirK) transcripts. These findings underscore the complexity of directly linking the structure of the microbial community to rates of biogeochemical processes.
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影响因子：
4.4
作者：
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通讯作者：
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