Name: workflow based on the combination of isotopic tracer experiments to investigate microbial metabolism of multiple nutrient sources
Uploaded: 2018-01-22T13:30:00
Description: Watch this Scientific Journal Video about Workflow Based on the Combination of Isotopic Tracer Experiments to Investigate Microbial Metabolism of Multiple Nutrient Sources at JoVE.com

我们感谢让-Roch Mouret, 西尔维亚 Dequin 和吉恩-玛丽 Sabalyrolles 为帮助的概念, 机器人辅助发酵系统和马丁 Pradal, 尼古拉布维尔和帕斯卡尔 Brial 为他们的技术支持。这一项目的经费由全国 Ministère 教育、de la 研究等技术提供。

1. 发酵和取样
<ol><li>
培养基和发酵的制备 注: 所有的发酵都是并行进行的, 使用相同的应变和相同的化学定义的合成介质 (SM, 在表 1中提供的成分), 其中包括铵和氨基酸的混合物作为氮源的15。对于每种发酵, 一个单一的氮化合物只提供一个统一标记的13C 或15N 形式 (100%), 而其余的则保持未标记。对于在实验组中使用的每个标记的氮源 ...

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利用同位素示踪实验, 通过代谢网络定量化化合物, 是了解微生物代谢操作的一种很有前途的方法。这种方法, 虽然成功地应用于一个或两个标记的基板, 目前不能实施研究的代谢各种来源使用多重标记元素同位素 (即, 超过两个基板)。事实上, 可用的分析技术能够准确地确定 proteinogenic 氨基酸和分子的标记模式, 仅当使用单一元素的同位素时, 并且可能时用两个元素进行联合标记。因此, 为了?...

了解微生物代谢如何运作是一个关键问题的设计有效的战略, 以改善发酵过程和调节生产的发酵化合物。在过去的二十年中, 基因组学和功能基因组学的进步, 在很大程度上促进了许多微生物代谢网络拓扑的知识的扩展。对此信息的访问导致了旨在全面概述蜂窝功能1的方法的发展。这些方法通常依赖于基于模型的可测量参数的解释。这些实验数据一方面包括代谢物的吸收率和生产率, 另一方面, 从同位素示踪实验中获得的定量的细胞内信息。这些数据提供了在定义的新陈代谢网络中的不同通路的体内活动的扣除的基本信息2,3,4。目前, 可用的分析技术只能够准确地检测分子在使用单元素同位素时的标记模式, 并可能在两个同位素元素的共同标记下。此外, 在大多数生长条件下, 碳源只由一个或两个化合物组成。因此, 基于碳基板上的13C 同位素示踪剂的方法得到了广泛和成功的应用, 以全面了解碳代谢网络的运行情况5,6,7 ,8。
相比之下, 在许多自然和工业环境中, 支持微生物生长的可用氮资源通常由广泛的分子组成。例如, 在葡萄酒或啤酒发酵过程中, 氮气作为18种氨基酸和铵的混合物提供, 在可变浓度下为9。这一系列的 N 类化合物, 可用于代谢使这些复杂的媒体条件大大不同于那些通常用于生理学研究, 因为后者是通过使用独特的氮源, 典型的铵。
总的来说, 内化的氮化合物可以直接纳入蛋白质或 catabolized。许多微生物的氮代谢网络结构, 包括酵母的酿酒酵母, 是非常复杂的根据基板的多样性。示意性地, 这个系统是基于氮代谢中心核心的组合, 它催化谷氨酰胺、谷氨酸和α-二的转换10,11, 具有转氨酶和 deaminases。通过这个网络, 胺基团从铵或其他氨基酸收集和α-酮酸释放。这些中间体也综合通过中央碳代谢 (CCM)12,13。这种大量的分支反应和中间体, 参与了外源氮源的分解和 proteinogenic 氨基酸的代谢, 满足了细胞的合成代谢要求。通过这些不同的相互连接的路线的活动也导致代谢物的排泄。特别是α-酮酸可以通过艾氏通路重定向产生更高的醇及其乙酸酯衍生物14, 这是产品感官图谱的重要贡献。随后, 氮代谢如何运作在生物质生产和挥发性分子 (香气) 的形成中起着关键作用。
有关氮代谢的反应、酶和基因在文献中有广泛的描述。然而, 在整个代谢网络中分配多种氮源的问题尚未得到解决。解释这种缺乏信息有两个主要原因。首先, 鉴于氮代谢网络的重要复杂性, 需要大量的定量数据才能完全了解它的运作, 直到现在。其次, 许多实验性的约束和分析方法的局限性阻碍了以前用于解释 CCM 函数的方法的实现。
为了克服这些问题, 我们选择了一种系统级的方法, 它是基于对一系列同位素示踪实验数据的核对。该工作流包括: -在相同环境条件下进行的一组发酵, 而不同的营养源 (基质) 每次都被标记。 -结合分析程序 (HPLC、gc-ms), 在发酵的不同阶段, 对被标记的基质的残留浓度和化合物的浓度和同位素富集进行精确测定。标记分子的分解代谢, 包括衍生生物质。 -计算每个被消耗标记的分子的质量和同位素平衡, 并对数据集进行进一步的综合分析, 以获得全球对微生物通过测定通量比值管理多种营养源的概览.
要应用这种方法, 必须注意培养菌株/微生物的可再生行为。此外, 在相同的发酵过程中, 必须采取不同文化的样品。在这篇手稿中所报道的实验工作中, 一个机器人辅助系统用于在线监测发酵, 以此来解释这些限制。
此外, 必须选择一套标签的基板 (化合物, 性质, 和位置的标签), 这是适当的, 以解决科学问题的研究。在这里, 15N 标记铵、谷氨酰胺和精氨酸被选为葡萄汁中发现的三主要氮源。这就允许评估从消耗化合物到 proteinogenic 氨基酸的氮再分配模式。我们还研究了被消耗的氨基酸的碳骨架的命运及其对挥发性分子生产的贡献。为了实现这一目标, 在研究中加入了一致的13C 标记亮氨酸、异亮氨酸、苏氨酸和缬氨酸, 这些氨基酸是从艾氏通路的主要中间体中获得的。
总的来说, 我们定量地探讨了酵母如何管理一个复杂的氮资源, 通过重新分配外源氮源, 以满足其合成代谢的要求, 在整个发酵, 而另外消除过剩的碳前体挥发性分子。本文所报道的实验方法可用于研究其他微生物所使用的多种营养源。这似乎是分析遗传背景或环境条件对微生物代谢行为的影响的适当方法。

<table>
	<tbody>
		<tr>
			<td>D-Glucose</td>
			<td>PanReac</td>
			<td>141341.0416</td>
			<td></td>
		</tr>
		<tr>
			<td>D-Fructose</td>
			<td>PanReac</td>
			<td>142728.0416</td>
			<td></td>
		</tr>
		<tr>
			<td>DL-Malic acid</td>
			<td>Sigma Aldrich</td>
			<td>M0875</td>
			<td></td>
		</tr>
		<tr>
			<td>Citric acid monohydrate</td>
			<td>Sigma Aldrich</td>
			<td>C7129</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium phosphate monobasic</td>
			<td>Sigma Aldrich</td>
			<td>P5379</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium sulfate</td>
			<td>Sigma Aldrich</td>
			<td>P0772</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium sulfate heptahydrate</td>
			<td>Sigma Aldrich</td>
			<td>230391</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcium chloride dihydrate</td>
			<td>Sigma Aldrich</td>
			<td>C7902</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>Sigma Aldrich</td>
			<td>S9625</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium chloride</td>
			<td>Sigma Aldrich</td>
			<td>A4514</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide</td>
			<td>Sigma Aldrich</td>
			<td>71690</td>
			<td></td>
		</tr>
		<tr>
			<td>Manganese sulfate monohydrate</td>
			<td>Sigma Aldrich</td>
			<td>M7634</td>
			<td></td>
		</tr>
		<tr>
			<td>Zinc sulfate heptahydrate</td>
			<td>Sigma Aldrich</td>
			<td>Z4750</td>
			<td></td>
		</tr>
		<tr>
			<td>Copper (II) sulfate pentahydrate</td>
			<td>Sigma Aldrich</td>
			<td>C7631</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium iodine</td>
			<td>Sigma Aldrich</td>
			<td>P4286</td>
			<td></td>
		</tr>
		<tr>
			<td>Cobalt (II) chloride hexahydrate</td>
			<td>Sigma Aldrich</td>
			<td>C3169</td>
			<td></td>
		</tr>
		<tr>
			<td>Boric acid</td>
			<td>Sigma Aldrich</td>
			<td>B7660</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium heptamolybdate</td>
			<td>Sigma Aldrich</td>
			<td>A7302</td>
			<td></td>
		</tr>
		<tr>
			<td>Myo-inositol</td>
			<td>Sigma Aldrich</td>
			<td>I5125</td>
			<td></td>
		</tr>
		<tr>
			<td>D-Pantothenic acid hemicalcium salt</td>
			<td>Sigma Aldrich</td>
			<td>21210</td>
			<td></td>
		</tr>
		<tr>
			<td>Thiamine, hydrochloride</td>
			<td>Sigma Aldrich</td>
			<td>T4625</td>
			<td></td>
		</tr>
		<tr>
			<td>Nicotinic acid</td>
			<td>Sigma Aldrich</td>
			<td>N4126</td>
			<td></td>
		</tr>
		<tr>
			<td>Pyridoxine</td>
			<td>Sigma Aldrich</td>
			<td>P5669</td>
			<td></td>
		</tr>
		<tr>
			<td>Biotine</td>
			<td>Sigma Aldrich</td>
			<td>B4501</td>
			<td></td>
		</tr>
		<tr>
			<td>Ergost&#233;rol</td>
			<td>Sigma Aldrich</td>
			<td>E6510</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween 80</td>
			<td>Sigma Aldrich</td>
			<td>P1754</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol absolute</td>
			<td>VWR Chemicals</td>
			<td>101074F</td>
			<td></td>
		</tr>
		<tr>
			<td>Iron (III) chloride hexahydrate</td>
			<td>Sigma Aldrich</td>
			<td>236489</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Aspartic acid</td>
			<td>Sigma Aldrich</td>
			<td>A9256</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutamic acid</td>
			<td>Sigma Aldrich</td>
			<td>G1251</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Alanine</td>
			<td>Sigma Aldrich</td>
			<td>A7627</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Arginine</td>
			<td>Sigma Aldrich</td>
			<td>A5006</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Cysteine</td>
			<td>Sigma Aldrich</td>
			<td>C7352</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutamine</td>
			<td>Sigma Aldrich</td>
			<td>G3126</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>Sigma Aldrich</td>
			<td>G7126</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Histidine</td>
			<td>Sigma Aldrich</td>
			<td>H8000</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Isoleucine</td>
			<td>Sigma Aldrich</td>
			<td>I2752</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Leucine</td>
			<td>Sigma Aldrich</td>
			<td>L8000</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Lysine</td>
			<td>Sigma Aldrich</td>
			<td>L5501</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Methionine</td>
			<td>Sigma Aldrich</td>
			<td>M9625</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Phenylalanine</td>
			<td>Sigma Aldrich</td>
			<td>P2126</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Proline</td>
			<td>Sigma Aldrich</td>
			<td>P0380</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Serine</td>
			<td>Sigma Aldrich</td>
			<td>S4500</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Threonine</td>
			<td>Sigma Aldrich</td>
			<td>T8625</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Tryptophane</td>
			<td>Sigma Aldrich</td>
			<td>T0254</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Tyrosine</td>
			<td>Sigma Aldrich</td>
			<td>T3754</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Valine</td>
			<td>Sigma Aldrich</td>
			<td>V0500</td>
			<td></td>
		</tr>
		<tr>
			<td>13C5-L-Valine</td>
			<td>Eurisotop</td>
			<td>CLM-2249-H-0.25</td>
			<td></td>
		</tr>
		<tr>
			<td>13C6-L-Leucine</td>
			<td>Eurisotop</td>
			<td>CLM-2262-H-0.25</td>
			<td></td>
		</tr>
		<tr>
			<td>15N-Ammonium chloride</td>
			<td>Eurisotop</td>
			<td>NLM-467-1</td>
			<td></td>
		</tr>
		<tr>
			<td>ALPHA-15N-L-Glutamine</td>
			<td>Eurisotop</td>
			<td>NLM-1016-1</td>
			<td></td>
		</tr>
		<tr>
			<td>U-15N4-L-Arginine</td>
			<td>Eurisotop</td>
			<td>NLM-396-PK</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl acetate</td>
			<td>Sigma Aldrich</td>
			<td>270989</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl propanoate</td>
			<td>Sigma Aldrich</td>
			<td>112305</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl 2-methylpropanoate</td>
			<td>Sigma Aldrich</td>
			<td>246085</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl butanoate</td>
			<td>Sigma Aldrich</td>
			<td>E15701</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl 2-methylbutanoate</td>
			<td>Sigma Aldrich</td>
			<td>306886</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl 3-methylbutanoate</td>
			<td>Sigma Aldrich</td>
			<td>8.08541.0250</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl hexanoate</td>
			<td>Sigma Aldrich</td>
			<td>148962</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl octanoate</td>
			<td>Sigma Aldrich</td>
			<td>W244910</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl decanoate</td>
			<td>Sigma Aldrich</td>
			<td>W243205</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl dodecanoate</td>
			<td>Sigma Aldrich</td>
			<td>W244112</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl lactate</td>
			<td>Sigma Aldrich</td>
			<td>W244015</td>
			<td></td>
		</tr>
		<tr>
			<td>Diethyl succinate</td>
			<td>Sigma Aldrich</td>
			<td>W237701</td>
			<td></td>
		</tr>
		<tr>
			<td>2-methylpropyl acetate</td>
			<td>Sigma Aldrich</td>
			<td>W217514</td>
			<td></td>
		</tr>
		<tr>
			<td>2-methylbutyl acetate</td>
			<td>Sigma Aldrich</td>
			<td>W364401</td>
			<td></td>
		</tr>
		<tr>
			<td>3-methyl butyl acetate</td>
			<td>Sigma Aldrich</td>
			<td>287725</td>
			<td></td>
		</tr>
		<tr>
			<td>2-phenylethyl acetate</td>
			<td>Sigma Aldrich</td>
			<td>290580</td>
			<td></td>
		</tr>
		<tr>
			<td>2-methylpropanol</td>
			<td>Sigma Aldrich</td>
			<td>294829</td>
			<td></td>
		</tr>
		<tr>
			<td>2-methylbutanol</td>
			<td>Sigma Aldrich</td>
			<td>133051</td>
			<td></td>
		</tr>
		<tr>
			<td>3-methylbutanol</td>
			<td>Sigma Aldrich</td>
			<td>309435</td>
			<td></td>
		</tr>
		<tr>
			<td>Hexanol</td>
			<td>Sigma Aldrich</td>
			<td>128570</td>
			<td></td>
		</tr>
		<tr>
			<td>2-phenylethanol</td>
			<td>Sigma Aldrich</td>
			<td>77861</td>
			<td></td>
		</tr>
		<tr>
			<td>Propanoic acid</td>
			<td>Sigma Aldrich</td>
			<td>94425</td>
			<td></td>
		</tr>
		<tr>
			<td>Butanoic acid</td>
			<td>Sigma Aldrich</td>
			<td>19215</td>
			<td></td>
		</tr>
		<tr>
			<td>2-methylpropanoic acid</td>
			<td>Sigma Aldrich</td>
			<td>58360</td>
			<td></td>
		</tr>
		<tr>
			<td>2-methylbutanoic acid</td>
			<td>Sigma Aldrich</td>
			<td>193070</td>
			<td></td>
		</tr>
		<tr>
			<td>3-methylbutanoic acid</td>
			<td>Sigma Aldrich</td>
			<td>W310212</td>
			<td></td>
		</tr>
		<tr>
			<td>Hexanoic acid</td>
			<td>Sigma Aldrich</td>
			<td>153745</td>
			<td></td>
		</tr>
		<tr>
			<td>Octanoic acid</td>
			<td>Sigma Aldrich</td>
			<td>W279900</td>
			<td></td>
		</tr>
		<tr>
			<td>Decanoic acid</td>
			<td>Sigma Aldrich</td>
			<td>W236403</td>
			<td></td>
		</tr>
		<tr>
			<td>Dodecanoic acid</td>
			<td>Sigma Aldrich</td>
			<td>L556</td>
			<td></td>
		</tr>
		<tr>
			<td>Fermentor 1L</td>
			<td>Legallais</td>
			<td>AT1357</td>
			<td>Fermenter handmade for fermentation</td>
		</tr>
		<tr>
			<td>Disposable vacuum filtration system</td>
			<td>Dominique Deutscher</td>
			<td>029311</td>
			<td></td>
		</tr>
		<tr>
			<td>Fermenters (250 ml)</td>
			<td>Legallais</td>
			<td>AT1352</td>
			<td>Fermenter handmade for fermentation</td>
		</tr>
		<tr>
			<td>Sterile tubes</td>
			<td>Sarstedt</td>
			<td>62.554.502</td>
			<td></td>
		</tr>
		<tr>
			<td>Fermentation locks</td>
			<td>Legallais</td>
			<td>AT1356</td>
			<td>Fermetation locks handmade for fermentation</td>
		</tr>
		<tr>
			<td>BactoYeast Extract</td>
			<td>Becton, Dickinson and Company</td>
			<td>212750</td>
			<td></td>
		</tr>
		<tr>
			<td>BactoPeptone</td>
			<td>Becton, Dickinson and Company</td>
			<td>211677</td>
			<td></td>
		</tr>
		<tr>
			<td>Incubator shaker</td>
			<td>Infors HT</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Particle Counter</td>
			<td>Beckman Coulter</td>
			<td>6605697</td>
			<td>Multisizer 3 Coulter Counter</td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Jouan</td>
			<td></td>
			<td>GR412</td>
		</tr>
		<tr>
			<td>Plate Butler Robotic system</td>
			<td>Lab Services BV</td>
			<td>PF0X-MA</td>
			<td>Automatic instrument</td>
		</tr>
		<tr>
			<td>Plate Butler Software</td>
			<td>Lab Services BV</td>
			<td></td>
			<td>Robot monitor software</td>
		</tr>
		<tr>
			<td>RobView</td>
			<td></td>
			<td></td>
			<td>In-house developed calculation software</td>
		</tr>
		<tr>
			<td>My SQL</td>
			<td></td>
			<td></td>
			<td>International source database</td>
		</tr>
		<tr>
			<td>Cimarec i Telesystem Multipoint Stirrers</td>
			<td>Thermo Fisher Scientific</td>
			<td>50088009</td>
			<td>String Drive 60</td>
		</tr>
		<tr>
			<td>BenchBlotter platform rocker</td>
			<td>Dutscher</td>
			<td>60903</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonia enzymatic kit</td>
			<td>R-Biopharm AG</td>
			<td>5390</td>
			<td></td>
		</tr>
		<tr>
			<td>Spectrophotometer cuvettes</td>
			<td>VWR</td>
			<td>634-0678</td>
			<td></td>
		</tr>
		<tr>
			<td>Spectrophotometer UviLine 9400</td>
			<td>Secomam</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Amino acids standards physiological - acidics and neutrals</td>
			<td>Sigma Aldrich</td>
			<td>A6407</td>
			<td></td>
		</tr>
		<tr>
			<td>Amino acids standards physiological - basics</td>
			<td>Sigma Aldrich</td>
			<td>A6282</td>
			<td></td>
		</tr>
		<tr>
			<td>Citrate lithium buffers - Ultra ninhydrin reagent</td>
			<td>Biochrom</td>
			<td>BC80-6000-06</td>
			<td></td>
		</tr>
		<tr>
			<td>Sulfosalycilic acid</td>
			<td>Sigma Aldrich</td>
			<td>S2130</td>
			<td></td>
		</tr>
		<tr>
			<td>Norleucine</td>
			<td>Sigma Aldrich</td>
			<td>N1398</td>
			<td></td>
		</tr>
		<tr>
			<td>Biochrom 30 AAA</td>
			<td>Biochrom</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>EZChrom Elite</td>
			<td>Biochrom</td>
			<td></td>
			<td>Instrument control and Data analysis software</td>
		</tr>
		<tr>
			<td>Ultropac 8 resin Lithium</td>
			<td>Biochrom</td>
			<td>BC80-6002-47</td>
			<td>Lithium High Resolution Physiological Column</td>
		</tr>
		<tr>
			<td>Filter Millex GV</td>
			<td>Merck Millipore</td>
			<td>SLGVX13NL</td>
			<td>Millex GV 13mm (pore size 0.22 &#181;m)</td>
		</tr>
		<tr>
			<td>Membrane filter PALL</td>
			<td>VWR</td>
			<td>514-4157</td>
			<td>Supor-450 47mm 0.45&#181;m</td>
		</tr>
		<tr>
			<td>Vacuum pump Millivac Mini</td>
			<td>Millipore</td>
			<td>XF5423050</td>
			<td></td>
		</tr>
		<tr>
			<td>Aluminium smooth weigh dish 70mm</td>
			<td>VWR</td>
			<td>611-1380</td>
			<td></td>
		</tr>
		<tr>
			<td>Precision balance</td>
			<td>Mettler</td>
			<td></td>
			<td>Specifications AE163</td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxid dried</td>
			<td>Merck</td>
			<td>1029310161</td>
			<td>(max. 0.025% H2O) SeccoSolv</td>
		</tr>
		<tr>
			<td>Combustion oven</td>
			<td>Legallais</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Pierce BCA protein assay kit</td>
			<td>Interchim</td>
			<td>UP40840A</td>
			<td></td>
		</tr>
		<tr>
			<td>Formic acid</td>
			<td>Fluka</td>
			<td>94318</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogen peroxide</td>
			<td>Sigma Aldrich</td>
			<td>H1009</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrochloric Acid Fuming 37% Emsure</td>
			<td>Merck</td>
			<td>1003171000</td>
			<td>Grade ACS,ISO,Reag. Ph Eur</td>
		</tr>
		<tr>
			<td>Lithium acetate buffer</td>
			<td>Biochrom</td>
			<td>80-2038-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Commercial solution of hydrolyzed amino acids</td>
			<td>Sigma Aldrich</td>
			<td>AAS18</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Methionine sulfone</td>
			<td>Sigma Aldrich</td>
			<td>M0876</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Cysteic acid monohydrate</td>
			<td>Sigma Aldrich</td>
			<td>30170</td>
			<td></td>
		</tr>
		<tr>
			<td>Pyrex glass culture tubes</td>
			<td>Sigma Aldrich</td>
			<td>Z653586</td>
			<td></td>
		</tr>
		<tr>
			<td>Pyridine</td>
			<td>Acros Organics</td>
			<td>131780500</td>
			<td>99% Extrapure</td>
		</tr>
		<tr>
			<td>Ethyl chloroformate</td>
			<td>Sigma Aldrich</td>
			<td>23131</td>
			<td></td>
		</tr>
		<tr>
			<td>Dichloromethane</td>
			<td>Sigma Aldrich</td>
			<td>32222</td>
			<td></td>
		</tr>
		<tr>
			<td>Vials</td>
			<td>Sigma Aldrich</td>
			<td>854165</td>
			<td></td>
		</tr>
		<tr>
			<td>Microinserts for 1.5ml vials</td>
			<td>Sigma Aldrich</td>
			<td>SU860066</td>
			<td></td>
		</tr>
		<tr>
			<td>GC/MS</td>
			<td>Agilent Technologies</td>
			<td>5890 GC/5973 MS</td>
			<td></td>
		</tr>
		<tr>
			<td>Chemstation</td>
			<td>Agilent Technologies</td>
			<td></td>
			<td>Instrument control and data analysis software</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Sigma Aldrich</td>
			<td>34860</td>
			<td>Chromasolv, for HPLC</td>
		</tr>
		<tr>
			<td>Acetonitrile</td>
			<td>Sigma Aldrich</td>
			<td>34998</td>
			<td>ChromasolvPlus, for HPLC</td>
		</tr>
		<tr>
			<td>N,N-Dimethylformamide dimethyl acetal</td>
			<td>Sigma Aldrich</td>
			<td>394963</td>
			<td></td>
		</tr>
		<tr>
			<td>BSTFA</td>
			<td>Sigma Aldrich</td>
			<td>33024</td>
			<td></td>
		</tr>
		<tr>
			<td>DB-17MS column</td>
			<td>Agilent Technologies</td>
			<td>122-4731</td>
			<td>30m*0.25mm*0.15&#181;m</td>
		</tr>
		<tr>
			<td>Sodium sulfate, anhydrous</td>
			<td>Sigma Aldrich</td>
			<td>238597</td>
			<td></td>
		</tr>
		<tr>
			<td>Technical nitrogen</td>
			<td>Air products</td>
			<td>14629</td>
			<td></td>
		</tr>
		<tr>
			<td>Zebron ZB-WAX column</td>
			<td>Phenomenex</td>
			<td>7HG-G007-11</td>
			<td>30m*0.25mm*0.25&#181;m</td>
		</tr>
		<tr>
			<td>Helium BIP</td>
			<td>Air products</td>
			<td>26699</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass Pasteur pipettes</td>
			<td>VWR</td>
			<td>612-1702</td>
			<td></td>
		</tr>
	</tbody>
</table>

workflow based on the combination of isotopic tracer experiments to investigate microbial metabolism of multiple nutrient sources

微生物学领域的研究依赖于各种方法的实施。特别是, 适当的方法的发展大大有助于提供广泛的知识代谢的微生物生长在化学定义的媒体含有独特的氮和碳源。相比之下, 通过多种营养来源的新陈代谢的管理, 尽管它们在自然或工业环境中的广泛存在, 仍然几乎未被探索。这种情况主要是由于缺乏适当的方法, 妨碍了调查工作。
我们报告一个实验策略, 以定量和全面地探讨新陈代谢是如何运作的, 当一个营养素作为不同的分子,即, 一个复杂的资源的混合物提供。在这里, 我们描述了它的应用, 通过酵母代谢网络评估多氮源的划分。该工作流结合了稳定同位素示踪实验中所获得的信息, 使用选定的13C 或15N 标记基板。它首先包括平行和可再生的发酵在同一个媒介, 包括 N 包含分子的混合物;但是, 每次选定的氮源都被标记。结合分析程序 (HPLC, gc-ms), 以评估目标化合物的标记模式, 并量化的消耗和回收的基质在其他代谢物。完整的数据集的综合分析提供了在细胞内消耗的基质的命运的概述。这种方法需要一个精确的协议, 收集 samples–facilitated 的机器人辅助系统的在线监测 fermentations–and 实现了大量的耗时分析。尽管有这些限制, 它还是第一次允许对酵母代谢网络中的多个氮源进行划分。我们阐明了从更丰富的来源向其他 n-化合物的氮的再分配, 并确定了挥发性分子和 proteinogenic 氨基酸的代谢来源。

图 3提供了工作流的示意图, 该流程图是为了调查在葡萄酒发酵过程中发现的多种氮源的酵母的管理情况而实施的。 对于不同的取样点, 生物 parameters–growth 特性、氮耗形态和 proteinogenic 氨基 acids–show 的剖面在发酵中具有很高的重现性 (图 4)。这种一致性根据在一组14独立发酵中生成的数据的组合来验证方法的相关性。
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Watch this Scientific Journal Video about Workflow Based on the Combination of Isotopic Tracer Experiments to Investigate Microbial Metabolism of Multiple Nutrient Sources at JoVE.com

Workflow Based on the Combination of Isotopic Tracer Experiments to Investigate Microbial Metabolism of Multiple Nutrient Sources

本议定书描述了一个实验过程, 定量和全面地研究多种营养来源的代谢。这一工作流程, 基于同位素示踪实验和分析程序的结合, 使被消耗的营养素的命运和由微生物综合的分子的新陈代谢的起源被确定。

基于同位素示踪实验结合的工作流研究多营养源的微生物代谢

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An Experimental Protocol for Assessing the Performance of New Ultrasound Probes Based on CMUT Technology in Application to Brain Imaging

基于 CMUT 技术的新型超声探头在脑成像中的应用研究

The possibility to perform an early and repeatable assessment of imaging performance is fundamental in the design and development process of new ...

Calorespirometry: A Powerful, Noninvasive Approach to Investigate Cellular Energy Metabolism

Calorespirometry: 一种功能强大、无创的研究细胞能量代谢的方法

Many cell lines used in basic biological and biomedical research maintain energy homeostasis through a combination of both aerobic and anaerobic ...

Conducting Multiple Imaging Modes with One Fluorescence Microscope

使用一个荧光显微镜进行多种成像模式

Fluorescence microscopy is a powerful tool to detect biological molecules in situ and monitor their dynamics and interactions in real-time. In addition to ...

Gene Expression Analysis of Endothelial Cells Exposed to Shear Stress Using Multiple Parallel-plate Flow Chambers

多平行板流室对剪切应力暴露的内皮细胞基因表达分析

We describe a workflow for the analysis of gene expression from endothelial cells subject to a steady laminar flow using multiple monitored parallel-plate ...

Generating Controlled, Dynamic Chemical Landscapes to Study Microbial Behavior

生成受控动态化学景观，研究微生物行为

We demonstrate a method for the generation of controlled, dynamic chemical pulses&#8213;where localized chemoattractant becomes suddenly available at the ...