Este trabalho foi financiado pelo Projeto Estratégico e Subsídios Descoberta a JDN das Ciências Naturais e Engenharia Council of Canada (NSERC).

<ol>
	<li>Neufeld, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DNA+stable-isotope+probing.">DNA stable-isotope probing.</a> Nat. Protocols. 2, 860-866 (2007).</li><li>Neufeld, J. D., Boden, R., Moussard, H., Sch&#228;fer, H., Murrell, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Substrate-specific+clades+of+active+marine+methylotrophs+associated+with+a+phytoplankton+bloom+in+a+temperate+coastal+environment.">Substrate-specific clades of active marine methylotrophs associated with a phytoplankton bloom in a temperate coastal environment.</a> Appl. Environ. Microbiol. 74, 7321-7328 (2009).</li><li>Nercessian, O., Noyes, E., Kalyuzhnaya, M. G., Lidstrom, M. E., Chistoserdova, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+populations+active+in+metabolism+of+C1+compounds+in+the+sediment+of+Lake+Washington,+a+freshwater+lake.">Bacterial populations active in metabolism of C1 compounds in the sediment of Lake Washington, a freshwater lake.</a> Appl. Environ. Microbiol. 71, 6885-6899 (2005).</li><li>Padmanabhan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Respiration+of+13C-labelled+substrates+added+to+soil+in+the+field+and+subsequent+16S+rRNA+gene+analysis+of+13C-labelled+soil+DNA.">Respiration of 13C-labelled substrates added to soil in the field and subsequent 16S rRNA gene analysis of 13C-labelled soil DNA.</a> Appl. Environ. Microbiol. 69, 1614-1622 (2003).</li><li>Bernard, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+and+identification+of+soil+microbial+populations+actively+assimilating+carbon+from+13C-labelled+wheat+residue+as+estimated+by+DNA-+and+RNA-SIP+techniques.">Dynamics and identification of soil microbial populations actively assimilating carbon from 13C-labelled wheat residue as estimated by DNA- and RNA-SIP techniques.</a> Environ. Microbiol. 9, 752-764 (2007).</li><li>Haichar, e. l. Z. a. h. a. r., F, . <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+cellulolytic+bacteria+in+soil+by+stable+isotope+probing.">Identification of cellulolytic bacteria in soil by stable isotope probing.</a> Environ. Microbiol. 9, 625-634 (2007).</li><li>Addison, S., McDonald, I., Lloyd-Jones, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stable+isotope+probing:+Technical+considerations+when+resolving+15N-labelled+RNA+in+gradients.">Stable isotope probing: Technical considerations when resolving 15N-labelled RNA in gradients.</a> J. Microbiol. Meth. 80, 70-75 (2009).</li><li>Buckley, D. H., Huangyutitham, V., Hsu, S. -. F., Nelson, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stable+isotope+probing+with+15N+achieved+by+disentangling+the+effects+of+genome+G+++C+content+and+isotope+enrichment+on+DNA+density.">Stable isotope probing with 15N achieved by disentangling the effects of genome G + C content and isotope enrichment on DNA density.</a> Appl. Environ. Microbiol. 73, 3189-3195 (2007).</li><li>Schwartz, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+growing+microorganisms+in+soil+by+stable+isotope+probing+with+H218O.">Characterization of growing microorganisms in soil by stable isotope probing with H218O.</a> Appl. Environ. Microbiol. 73, 2541-2546 (2007).</li><li>Neufeld, J. D., Dumont, M. G., Vohra, J., Murrell, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methodological+considerations+for+the+use+of+stable+isotope+probing+in+microbial+ecology.">Methodological considerations for the use of stable isotope probing in microbial ecology.</a> Microb. Ecol. 53, 435-442 (2007).</li><li>Martineau, C., Whyte, L., Greer, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+SYBR+safe+technique+for+the+sensitive+detection+of+DNA+in+cesium+chloride+density+gradients+for+stable+isotope+probing+assays.">Development of a SYBR safe technique for the sensitive detection of DNA in cesium chloride density gradients for stable isotope probing assays.</a> J. Microbiol. Meth. 73, 199-202 (2008).</li><li>Bartram, A. K., Poon, C., Neufeld, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nucleic+acid+contamination+of+glycogen+used+in+nucleic+acid+precipitation+and+assessment+of+linear+polyacrylamide+as+an+alternative+co-precipitant.">Nucleic acid contamination of glycogen used in nucleic acid precipitation and assessment of linear polyacrylamide as an alternative co-precipitant.</a> Biotechniques. 47, 1019-1022 (2009).</li><li>Chen, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Revealing+the+uncultivated+majority:+combining+DNA+stable-isotope+probing,+multiple+displacement+amplification+and+metagenomic+analyses+of+uncultivated+Methylocystis+in+acidic+peatlands.">Revealing the uncultivated majority: combining DNA stable-isotope probing, multiple displacement amplification and metagenomic analyses of uncultivated Methylocystis in acidic peatlands.</a> Environ. Microbiol. 10, 2609-2622 (2008).</li><li>Neufeld, J. D., Chen, Y., Dumont, M. G., Murrell, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Marine+methylotrophs+revealed+by+stable-isotope+probing,+multiple+displacement+amplification+and+metagenomics.">Marine methylotrophs revealed by stable-isotope probing, multiple displacement amplification and metagenomics.</a> Environ. Microbiol. 10, 1526-1535 (2008).</li><li>Kalyuzhnaya, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-resolution+metagenomics+targets+specific+functional+types+in+complex+microbial+communities.">High-resolution metagenomics targets specific functional types in complex microbial communities.</a> Nat. Biotechnol. 26, 1029-1034 (2008).</li><li>Binga, E. K., Lasken, R. S., Neufeld, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Something+from+(almost)+nothing:+the+impact+of+multiple+displacement+amplification+on+microbial+ecology.">Something from (almost) nothing: the impact of multiple displacement amplification on microbial ecology.</a> ISME J. 2, 233-241 (2008).</li><li>Green, S. J., Leigh, M. B., Neufeld, J. D., Timmis, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Microbiology of Hydrocarbon and Lipid Microbiology. , 4137-4158 (2010).</li><li>Neufeld, J. D., Wagner, M., Murrell, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Who+eats+what,+where+and+when?+Isotope-labelling+experiments+are+coming+of+age.">Who eats what, where and when? Isotope-labelling experiments are coming of age.</a> ISME J. 1, 103-110 (2007).</li><li>Gallagher, E., McGuinness, L., Phelps, C., Young, L. Y., Kerkhof, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DNA+shortens+the+incubation+time+needed+to+detect+benzoate-utilizing+denitrifying+bacteria+by+stable-isotope+probing.">DNA shortens the incubation time needed to detect benzoate-utilizing denitrifying bacteria by stable-isotope probing.</a> Appl. Environ. Microbiol. 71, 5192-5196 .</li></ol>

Não há conflitos de interesse declarados.

Projeto adequado de isótopos estáveis ​​experimentos sondagem é de importância crítica para a obtenção de DNA marcado acima da comunidade de fundo sem rótulo. Considerações sobre a amostra de tempos de incubação, as concentrações de substrato, condições de incubação (por exemplo, nutrientes, teor de umidade do solo), cross-alimentação e replicação têm sido discutidas em outros lugares 10,18 e recomendamos ao leitor consultar estas publicações quando se projeta um incubação SIP. ...

<table><tbody><tr><td>Bromophenol Blue</td><td>Reagent</td><td>Fisher Scientific</td><td>BP115-25</td><td></td></tr><tr><td>Cesium chloride</td><td>Reagent</td><td>Fisher Scientific</td><td>BP210-500</td><td></td></tr><tr><td>Ethanol, reagent grade</td><td>Reagent</td><td>Sigma-Aldrich</td><td>652261</td><td></td></tr><tr><td>Ethidium bromide</td><td>Reagent</td><td>Sigma-Aldrich</td><td>E1510</td><td></td></tr><tr><td>Hydrochloric acid</td><td>Reagent</td><td>Fisher Scientific</td><td>351285212</td><td></td></tr><tr><td>Linear polyacrylamide</td><td>Reagent</td><td>Applichem</td><td>A6587</td><td></td></tr><tr><td>Polyethylene Glycol 6000</td><td>Reagent</td><td>VWR international</td><td>CAPX1286L-4</td><td></td></tr><tr><td>Potassium Chloride</td><td>Reagent</td><td>Fisher Scientific</td><td>AC42409-0010</td><td></td></tr><tr><td>Sodium Chloride</td><td>Reagent</td><td>Fisher Scientific</td><td>S2711</td><td></td></tr><tr><td>Sodium Hydroxide pellets</td><td>Reagent</td><td>Fisher Scientific</td><td>S3181</td><td></td></tr><tr><td>Tris base</td><td>Reagent</td><td>Fisher Scientific</td><td>BP1521</td><td></td></tr><tr><td>Dark Reader</td><td>Equipment</td><td>Clare Chemical</td><td>DR46B</td><td></td></tr><tr><td>Microcentrifuge</td><td>Equipment</td><td>Eppendorf</td><td>5424 000.410</td><td></td></tr><tr><td>Nanodrop 2000</td><td>Equipment</td><td>Fisher Scientific</td><td>361013650</td><td></td></tr><tr><td>Infusion pump</td><td>Equipment</td><td>Braintree Scientific, Inc.</td><td>N/A</td><td>Model Number: BSP&lt;br/&gt;See &lt;a href=&quot;http://www.braintreesci.com&quot;&gt;www.braintreesci.com&lt;/a&gt; for ordering details.</td></tr><tr><td>Tube sealer</td><td>Equipment</td><td>Beckman Coulter Inc.</td><td>358312</td><td></td></tr><tr><td>Ultracentrifuge</td><td>Equipment</td><td>Beckman Coulter Inc.</td><td></td><td></td></tr><tr><td>Ultracentrifuge rotor</td><td>Equipment</td><td>Beckman Coulter Inc.</td><td>362754</td><td></td></tr><tr><td>Ultraviolet light source</td><td>Equipment</td><td>UVP Inc.</td><td>95-0017-09</td><td>Any UV source will suffice</td></tr><tr><td>Ultraviolet light face shield</td><td>Equipment</td><td>Fisher Scientific</td><td>114051C</td><td></td></tr><tr><td>Butyl rubber stoppers, gray</td><td>Material</td><td>Sigma-Aldrich</td><td>27232</td><td></td></tr><tr><td>Centrifuge tubes</td><td>Material</td><td>Beckman Coulter Inc.</td><td>342412</td><td></td></tr><tr><td>Hypodermic needle, 23 gauge, 2&amp;#8221; length</td><td>Material</td><td>BD Biosciences</td><td>305145</td><td></td></tr><tr><td>Microfuge tubes, 1.5 mL</td><td>Material</td><td>DiaMed</td><td>AD151-N500</td><td></td></tr><tr><td>Open center seals, 20 mm diameter</td><td>Material</td><td>Sigma-Aldrich</td><td>27230-U</td><td></td></tr><tr><td>Pasteur pipettes, glass</td><td>Material</td><td>Fisher Scientific</td><td>13-678-6C</td><td></td></tr><tr><td>Pipet tips</td><td>Material</td><td>DiaMed</td><td>BPS340-1000</td><td>Catalogue number is for 200 &amp;#x03BC;l tips. 10 or 20 &amp;#x03BC;l tips may be purchased from the same source</td></tr><tr><td>Pump tubing 1.5 mm bore x 1.5 mm wall</td><td>Material</td><td>Appleton Woods</td><td></td><td></td></tr><tr><td>Screw-cap tubes, 15 mL</td><td>Material</td><td>DiaMed</td><td>AD15MLP-S</td><td></td></tr><tr><td>Serum vials, 125 mL volume</td><td>Material</td><td>Sigma-Aldrich</td><td>Z114014</td><td></td></tr><tr><td>Syringe, 60 mL</td><td>Material</td><td>BD Biosciences</td><td>309653</td><td></td></tr></tbody></table>

dna stable-isotope probing (dna-sip)

DNA estável-isótopo sondagem (DNA-SIP) é uma técnica poderosa para a identificação de microorganismos ativos que assimilar substratos de carbono especial e nutrientes em biomassa celular. Como tal, esta técnica de cultivo independente tem sido uma metodologia importante para a atribuição de função metabólica para as diversas comunidades que habitam uma grande variedade de ambientes terrestres e aquáticos. Após a incubação de uma amostra ambiental com isótopos estáveis ​​compostos marcados, extraídos de ácido nucléico é submetido a ultracentrifugação de gradiente de densidade e fracionamento gradiente subseqüentes para separar ácidos nucléicos de densidades diferentes. Purificação de DNA a partir de cloreto de césio recupera rotulados e não rotulados DNA para a caracterização molecular posterior (por exemplo, impressões digitais, microarrays, bibliotecas clone, metagenomics). Este protocolo fornece vídeo JOVE visuais passo-a-passo explicações do protocolo para fracionamento de gradiente de densidade gradiente de ultracentrifugação, e recuperação de DNA rotulados. O protocolo também inclui dados de amostra SIP e destaca dicas importantes e cuidados que devem ser considerados para garantir uma análise de DNA SIP-sucedido.

Watch this Scientific Journal Video about DNA Stable-Isotope Probing DNA-SIP at JoVE.com

DNA Stable-Isotope Probing DNA-SIP

DNA estável-isótopo sondagem é um método de cultivo independente para identificar e caracterizar as comunidades ativa de microorganismos que são capazes de utilizar substratos específicos. Assimilação do substrato enriquecido em isótopo pesado leva a incorporação de átomos marcados em biomassa microbiana. Ultracentrifugação em gradiente de densidade recupera DNA marcado para jusante análises moleculares.

DNA-Stable Isotope Probing (DNA-SIP)

DNA stable-isotope probing (DNA-SIP) is a powerful technique for identifying active microorganisms that assimilate particular carbon substrates and ...

Universidad de Cartagena UDEC

Research

JoVE Journal

Biology

DNA Stable-Isotope Probing (DNA-SIP)

43.9K visualizações.  University of Waterloo. DNA estável-isótopo sondagem é um método de cultivo independente para identificar e caracterizar as comunidades ativa de microorganismos que são capazes de utilizar substratos específicos. Assimilação do substrato enriquecido em isótopo pesado leva a incorporação de átomos marcados em biomassa microbiana. Ultracentrifugação em gradiente de densidade recupera DNA marcado para jusante análises moleculares.

Vídeo: DNA Stable-Isotope Probing DNA-SIP

Design and Operation of a Continuous 13C and 15N Labeling Chamber for Uniform or Differential, Metabolic and Structural, Plant Isotope Labeling

Tracing rare stable isotopes from plant material through the ecosystem provides the most sensitive information about ecosystem processes; from CO2 fluxes and soil organic matter formation to small-scale stable-isotope biomarker probing. Coupling multiple stable isotopes such as 13C with 15N, 18O or&#160;2H has the potential to reveal even more information about complex stoichiometric relationships during biogeochemical transformations. Isotope labeled plant material has been used in various studies of litter decomposition and soil organic matter formation1-4. From these and other studies, however, it has become apparent that structural components of plant material behave differently than metabolic components (i.e. leachable low molecular weight compounds) in terms of microbial utilization and long-term carbon storage5-7. The ability to study structural and metabolic components separately provides a powerful new tool for advancing the forefront of ecosystem biogeochemical studies. Here we describe a method for producing 13C and 15N labeled plant material that is either uniformly labeled throughout the plant or differentially labeled in structural and metabolic plant components.
Here, we present the construction and operation of a continuous 13C and 15N labeling chamber that can be modified to meet various research needs. Uniformly labeled plant material is produced by continuous labeling from seedling to harvest, while differential labeling is achieved by removing the growing plants from the chamber weeks prior to harvest. Representative results from growing Andropogon gerardii Kaw demonstrate the system&#39;s ability to efficiently label plant material at the targeted levels. Through this method we have produced plant material with a 4.4 atom%13C and 6.7 atom%15N uniform plant label, or material that is differentially labeled by up to 1.29 atom%13C and 0.56 atom%15N in its metabolic and structural components (hot water extractable and hot water residual components, respectively). Challenges lie in maintaining proper temperature, humidity, CO2 concentration,&#160;and light levels in an airtight 13C-CO2 atmosphere for successful plant production. This chamber description represents a useful research tool to effectively produce uniformly or differentially multi-isotope labeled plant material for use in experiments on ecosystem biogeochemical cycling.

Design and Operation of a Continuous 13C and 15N Labeling Chamber for Uniform or Differential, Metabolic and Structural, Plant Isotope Labeling

This method explains how to build and operate a continuous 13C and 15N isotope labeling chamber for uniform or differential plant tissue labeling. Representative results from metabolic and structural labeling of Andropogon gerardii are discussed.

Projeto e operação de uma contínua<sup&gt; 13</sup&gt; C e<sup&gt; 15</sup&gt; N Labeling Câmara de uniforme ou Diferencial, metabólica e estrutural, Fábrica de Marcação por Isótopo

Tracing rare stable isotopes from plant material through the ecosystem provides the most sensitive information about ecosystem processes; from CO2 fluxes ...

Ambiente

A Method for Measuring Metabolism in Sorted Subpopulations of Complex Cell Communities Using Stable Isotope Tracing

Mammalian cell types exhibit specialized metabolism, and there is ample evidence that various co-existing cell types engage in metabolic cooperation. Moreover, even cultures of a single cell type may contain cells in distinct metabolic states, such as resting or cycling cells. Methods for measuring metabolic activities of such subpopulations are valuable tools for understanding cellular metabolism. Complex cell populations are most commonly separated using a cell sorter, and subpopulations isolated by this method can be analyzed by metabolomics methods. However, a problem with this approach is that the cell sorting procedure subjects cells to stresses that may distort their metabolism.
To overcome these issues, we reasoned that the mass isotopomer distributions (MIDs) of metabolites from cells cultured with stable isotope-labeled nutrients are likely to be more stable than absolute metabolite concentrations, because MIDs are formed over longer time scales and should be less affected by short-term exposure to cell sorting conditions. Here, we describe a method based on this principle, combining cell sorting with liquid chromatography-high resolution mass spectrometry (LC-HRMS). The procedure involves analyzing three types of samples: (1) metabolite extracts obtained directly from the complex population; (2) extracts of "mock sorted" cells passed through the cell sorter instrument without gating any specific population; and (3) extracts of the actual sorted populations. The mock sorted cells are compared against direct extraction to verify that MIDs are indeed not altered by the cell sorting procedure itself, prior to analyzing the actual sorted populations. We show example results from HeLa cells sorted according to cell cycle phase, revealing changes in nucleotide metabolism.

This article describes a method for studying cellular metabolism in complex communities of multiple cell types, using a combination of stable isotope tracing, cell sorting to isolate specific cell types, and mass spectrometry.

Um método para medir o metabolismo em Ordenado subpopulações de Comunidades celulares complexas usando Stable Isotope Tracing

Mammalian cell types exhibit specialized metabolism, and there is ample evidence that various co-existing cell types engage in metabolic cooperation. ...

Bioquímica

Reconstitution of Nucleosomes with Differentially Isotope-labeled Sister Histones

Asymmetrically modified nucleosomes contain the two copies of a histone (sister histones) decorated with distinct sets of Post-translational Modifications (PTMs). They are newly identified species with unknown means of establishment and functional implications. Current analytical methods are inadequate to detect the copy-specific occurrence of PTMs on the nucleosomal sister histones. This protocol presents a biochemical method for the in vitro reconstitution of nucleosomes containing differentially isotope-labeled sister histones. The generated complex can be also asymmetrically modified, after including a premodified histone pool during refolding of histone subcomplexes. These asymmetric nucleosome preparations can be readily reacted with histone-modifying enzymes to study modification cross-talk mechanisms imposed by the asymmetrically pre-incorporated PTM using nuclear magnetic resonance (NMR) spectroscopy. Particularly, the modification reactions in real-time can be mapped independently on the two sister histones by performing different types of NMR correlation experiments, tailored for the respective isotope type. This methodology provides the means to study crosstalk mechanisms that contribute to the formation and propagation of asymmetric PTM patterns on nucleosomal complexes.

This protocol describes the reconstitution of nucleosomes containing differentially isotope-labeled sister histones. At the same time, asymmetrically post-translationally modified nucleosomes can be generated after using a premodified histone copy. These preparations can be readily used to study modification crosstalk mechanisms, simultaneously on both sister histones, by using high-resolution NMR spectroscopy.

Reconstituição de Nucleosomes com Histones irmã diferencialmente Isotope-rotulados

Asymmetrically modified nucleosomes contain the two copies of a histone (sister histones) decorated with distinct sets of Post-translational Modifications ...

Fatty Acid 13C Isotopologue Profiling Provides Insight into Trophic Carbon Transfer and Lipid Metabolism of Invertebrate Consumers

Fatty acids (FAs) are useful biomarkers in food web ecology because they are typically assimilated as a complete molecule and transferred into consumer tissue with minor or no modification, allowing the dietary routing between different trophic levels. However, the FA trophic marker approach is still hampered by the limited knowledge in lipid metabolism of the soil fauna. This study used entirely labelled palmitic acid (13C16:0, 99 atom%) as a tracer in fatty acid metabolism pathways of two widespread soil Collembola, Protaphorura fimata and Heteromurus nitidus. In order to investigate the fate and metabolic modifications of this precursor, a method of isotopologue profiling is presented, performed by mass spectrometry using single ion monitoring. Moreover, the upstream laboratory feeding experiment is described, as well as the extraction and methylation of dominant lipid fractions (neutral lipids, phospholipids) and the related formula and calculations. Isotopologue profiling does not only yield the overall 13C enrichment in fatty acids derived from the 13C labeled precursor but also produces the pattern of isotopologues exceeding the mass of the parent ion (i.e., the FA molecular ion M+) of each labeled FA by one or more mass units (M+1, M+2, M+3, etc.). This knowledge allows conclusions on the ratio of dietary routing of an entirely consumed FA in comparison to de novo biosynthesis. The isotopologue profiling is suggested as a useful tool for evaluation of fatty acid metabolism in soil animals to disentangle trophic interactions.

Fatty Acid 13C Isotopologue Profiling Provides Insight into Trophic Carbon Transfer and Lipid Metabolism of Invertebrate Consumers

The fatty acid trophic marker approach, i.e., the assimilation of fatty acids as entire molecule and transfer into consumer tissue with no or minor modification, is hampered by knowledge gaps in fatty acid metabolism of small soil invertebrates. Isotopologue profiling is provided as a valuable tool to disentangle trophic interactions.

Ácido graxo 13C Isotopólogo de criação de perfil fornece insights sobre transferência de carbono trófica e metabolismo lipídico dos consumidores invertebrados

Fatty acids (FAs) are useful biomarkers in food web ecology because they are typically assimilated as a complete molecule and transferred into consumer ...

Sampling and Pretreatment of Tooth Enamel Carbonate for Stable Carbon and Oxygen Isotope Analysis

Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been applied in paleodietary, paleoecological, and paleoenvironmental research from recent historical periods back to over 10 million years ago. Bulk approaches provide a representative sample for the period of enamel mineralization, while sequential samples within a tooth can track dietary and environmental changes during this period. While these methodologies have been widely applied and described in archaeology, ecology, and paleontology, there have been no explicit guidelines to aid in the selection of necessary lab equipment and to thoroughly describe detailed laboratory sampling and protocols. In this article, we document textually and visually, the entire process from sampling through pretreatment and diagenetic screening to make the methodology more widely available to researchers considering its application in a variety of laboratory settings.

Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been used as a proxy for individual diet and environmental reconstruction. Here, we provide a detailed description and visual documentation of bulk and sequential tooth enamel sampling as well as pretreatment of archaeological and paleontological samples.

Amostragem e tratamento prévio de esmalte do dente carbonato de carbono estável e análise de isótopos de oxigênio

Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been applied in paleodietary, paleoecological, and ...

Rastreamento de isótopos estáveis e análise LC-MS para medir as atividades de DHODH e SDH

Oxygen-Independent Assays to Measure Mitochondrial Function in Mammals

The flow of electrons in the mitochondrial electron transport chain (ETC) supports multifaceted biosynthetic, bioenergetic, and signaling functions in mammalian cells. As oxygen (O2) is the most ubiquitous terminal electron acceptor for the mammalian ETC, the O2 consumption rate is frequently used as a proxy for mitochondrial function. However, emerging research demonstrates that this parameter is not always indicative of mitochondrial function, as fumarate can be employed as an alternative electron acceptor to sustain mitochondrial functions in hypoxia. This article compiles a series of protocols that allow researchers to measure mitochondrial function independently of the O2 consumption rate. These assays are particularly useful when studying mitochondrial function in hypoxic environments. Specifically, we describe methods to measure mitochondrial ATP production, de novo pyrimidine biosynthesis, NADH oxidation by complex I, and superoxide production. In combination with classical respirometry experiments, these orthogonal and economical assays will provide researchers with a more comprehensive assessment of mitochondrial function in their system of interest.

Autor em destaque: ensaios independentes de oxigênio para medir a função mitocondrial em mamíferos  

Here, we present a compilation of assays to directly measure mitochondrial function in mammalian cells independently of their ability to consume molecular oxygen.

Ensaios Independentes de Oxigênio para Medir a Função Mitocondrial em Mamíferos

The flow of electrons in the mitochondrial electron transport chain (ETC) supports multifaceted biosynthetic, bioenergetic, and signaling functions in ...

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

Studies in the field of microbiology rely on the implementation of a wide range of methodologies. In particular, the development of appropriate methods substantially contributes to providing extensive knowledge of the metabolism of microorganisms growing in chemically defined media containing unique nitrogen and carbon sources. In contrast, the management through metabolism of multiple nutrient sources, despite their broad presence in natural or industrial environments, remains virtually unexplored. This situation is mainly due to the lack of suitable methodologies, which hinders investigations.
We report an experimental strategy to quantitatively and comprehensively explore how metabolism operates when a nutrient is provided as a mixture of different molecules, i.e., a complex resource. Here, we describe its application for assessing the partitioning of multiple nitrogen sources through the yeast metabolic network. The workflow combines information obtained during stable isotope tracer experiments using selected 13C- or 15N-labeled substrates. It first consists of parallel and reproducible fermentations in the same medium, which includes a mixture of N-containing molecules; however,a selected nitrogen source is labeled each time. A combination of analytical procedures (HPLC, GC-MS) is implemented to assess the labeling patterns of targeted compounds and to quantify the consumption and recovery of substrates in other metabolites. An integrated analysis of the complete dataset provides an overview of the fate of consumed substrates within cells. This approach requires an accurate protocol for the collection of samples&#8211;facilitated by a robot-assisted system for online monitoring of fermentations&#8211;and the achievement of numerous time-consuming analyses. Despite these constraints, it allowed understanding, for the first time, the partitioning of multiple nitrogen sources throughout the yeast metabolic network. We elucidated the redistribution of nitrogen from more abundant sources toward other N-compounds and determined the metabolic origins of volatile molecules and proteinogenic amino acids.

This protocol describes an experimental procedure to quantitatively and comprehensively investigate the metabolism of multiple nutrient sources. This workflow, based on a combination of isotopic tracer experiments and an analytical procedure, allows the fate of consumed nutrients and the metabolic origin of molecules synthetized by microorganisms to be determined.

Fluxo de trabalho baseado na combinação de traçador isotópico experimentos para investigar o metabolismo microbiano de múltiplas fontes de nutrientes

Studies in the field of microbiology rely on the implementation of a wide range of methodologies. In particular, the development of appropriate methods ...

Bioengenharia

Stable Isotopic Profiling of Intermediary Metabolic Flux in Developing and Adult Stage Caenorhabditis elegans

Stable isotopic profiling has long permitted sensitive investigations of the metabolic consequences of genetic mutations and/or pharmacologic therapies in cellular and mammalian models. Here, we describe detailed methods to perform stable isotopic profiling of intermediary metabolism and metabolic flux in the nematode, Caenorhabditis elegans. Methods are described for profiling whole worm free amino acids, labeled carbon dioxide, labeled organic acids, and labeled amino acids in animals exposed to stable isotopes either from early development on nematode growth media agar plates or beginning as young adults while exposed to various pharmacologic treatments in liquid culture. Free amino acids are quantified by high performance liquid chromatography (HPLC) in whole worm aliquots extracted in 4% perchloric acid. Universally labeled 13C-glucose or 1,6-13C2-glucose is utilized as the stable isotopic precursor whose labeled carbon is traced by mass spectrometry in carbon dioxide (both atmospheric and dissolved) as well as in metabolites indicative of flux through glycolysis, pyruvate metabolism, and the tricarboxylic acid cycle. Representative results are included to demonstrate effects of isotope exposure time, various bacterial clearing protocols, and alternative worm disruption methods in wild-type nematodes, as well as the relative extent of isotopic incorporation in mitochondrial complex III mutant worms (isp-1(qm150)) relative to wild-type worms. Application of stable isotopic profiling in living nematodes provides a novel capacity to investigate at the whole animal level real-time metabolic alterations that are caused by individual genetic disorders and/or pharmacologic therapies.

Stable Isotopic Profiling of Intermediary Metabolic Flux in Developing and Adult Stage Caenorhabditis elegans

Stable isotopic profiling by gas chromatography mass spectrometric analysis of intermediary metabolic flux is described in the nematode, Caenorhabditis elegans. Methods are detailed for assessing isotopic enrichment in carbon dioxide, organic acids, and amino acids following isotope exposure either during development on agar plates or during adulthood in liquid culture.

Profiling isotópicas estáveis ​​de fluxo metabólico intermediário na fase de desenvolvimento e Adultos Caenorhabditis elegans</em

Stable isotopic profiling has long permitted sensitive investigations of the metabolic consequences of genetic mutations and/or pharmacologic therapies in ...

DNA-Stable Isotope Probing (DNA-SIP)

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Fluxo de trabalho baseado na combinação de traçador isotópico experimentos para investigar o metabolismo microbiano de múltiplas fontes de nutrientes

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Ácido graxo 13C Isotopólogo de criação de perfil fornece insights sobre transferência de carbono trófica e metabolismo lipídico dos consumidores invertebrados

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Fluxo de trabalho baseado na combinação de traçador isotópico experimentos para investigar o metabolismo microbiano de múltiplas fontes de nutrientes

Profiling isotópicas estáveis ​​de fluxo metabólico intermediário na fase de desenvolvimento e Adultos Caenorhabditis elegans

Ácido graxo ¹³C Isotopólogo de criação de perfil fornece insights sobre transferência de carbono trófica e metabolismo lipídico dos consumidores invertebrados

Profiling isotópicas estáveis de fluxo metabólico intermediário na fase de desenvolvimento e Adultos Caenorhabditis elegans