Reconhecemos o Centro de Genética Caenorhabditis para C. estirpes elegans. Suporte O financiamento foi fornecido pelo Instituto de Pesquisa Fox Terry. Agradecemos também o apoio concedido à EP da Rolande e Marcel Gosselin Graduate Studentship ea bolsa de formação CIHR / FRSQ em FRN53888 do Programa Integrado de Formação McGill Cancer Research investigação do cancro.

1. Preparação dos Reagentes <ol><li> Preparação da mídia para C. crescimento elegans (neste caso, os animais selvagens e animais flcn-1 (ok975) mutantes). <ol><li> Prepare modificado apenas de Bacto-peptona (BOYM) mistura seca do Youngren contendo 5,5 g de Tris-HCl, 2,4 g de base Tris, 31 g de Bactopetone, 20 g de NaCl e 0,08 g de colesterol. Misture bem com agitação. NOTA: Esta mistura é suficiente para preparar 10 L de meio de MYOB. NOTA: placas normais meio de crescimento (NGM) poderia ser usado em vez de MYOB placas 27. No entanto, o mesmo tipo de placas deve ser utilizada para comparações válidas entre estirpes e entre as repetições independentes. Neste protocolo, nós só usamos placas MYOB. </li><li> Prepare 1 L de meio BOYM por adição de 6 g de BOYM mistura seca, 17 g de ágar e perfazer o volume de 1 litro com H 2 O e autoclave durante 45 min a 122 ° C. Verter em placas e deixar secar à temperatura ambiente durante 2 dias. </li><li> Utilizando uma técnica estéril, inocular 100 ml de culture de meio de caldo LB com E. bactérias coli OP50 e crescer O / N a 37 ° C. </li><li> Placas MYOB semente com E. bactérias coli OP50. Deixe-a crescer à temperatura ambiente durante 48 horas. </li></ol></li><li> Preparação para a regulação negativa do gene usando RNAi <ol><li> Prepare MYOB placas RNAi-alimentação. Proceder como em passos 1.1.1 e 1.1.2. Após autoclavagem, permitir que o meio arrefeça até cerca de 55 ° C e adiciona-se 1 ml de 1 M de isopropilo β-D-1-tiogalactopiranósido (IPTG) e 1 ml de 100 mM de ampicilina. </li><li> Streak E. coli HT115 bactérias transformadas com um plasmídeo que exprime ou EV ou controlo RNAi flcn-1 específico em ampicilina (50 ug / mL) / tetraciclina (15 ug / ml) em placas de agar. Crescer a cultura O / N a 37 ° C. </li><li> Escolha colônias e inocular E. coli HT115 bactérias transformadas com um plasmídeo que exprime ou EV ou controlo flcn-1 RNAi específico e crescer a cultura em LB / ampicilina (50 ug / ml) e meio O / N a 37 &amp; #176; C. </li><li> Placas de sementes com E. coli HT115 EV bactérias ou HT115 flcn-1 bactérias de ARNi. NOTA: Manter placas de 48 horas à temperatura ambiente antes do uso. Se RNAi knockdown por alimentação é eficaz em, utilizar outros métodos de entrega da ARN-DS 28. </li></ol></li><li> Induzir o estresse oxidativo utilizando paraquat (PQ): <ol><li> Preparar tampão M9 por mistura de 3 g de KH 2 PO 4, 6 g de Na 2 HPO 4, 5 g de NaCl e 0,25 g de MgSO 4 7 · H2O Traga até 1 L com água destilada. Solução em autoclave durante 45 min a 122 ° C e armazenar garrafas à TA. </li><li> No dia do ensaio, preparar a solução de M9 / PQ contendo. Para este protocolo, utilizar PQ 100 mM (0,1028 g de PQ dissolvido em 4 ml de tampão M9 preenche toda uma placas de 96 poços com 40 ul de M9 / PQ por poço). CUIDADO: PQ é um composto altamente tóxico e perigoso. Manusear de acordo com as orientações adequadas. NOTA: Quando a primeira a executar um novo scomboio ou de uma nova condição, recomenda-se a ensaio de sobrevivência em concentrações crescentes de PQ para determinar a melhor concentração de usar, a fim de matar os animais dentro de 7-10 horas. </li></ol></li></ol> 2. Preparação de Age-sincronizado L4 População <ol><li> Transferir 20 hermafroditas adultas grávidas a uma placa de MYOB fresco semeado com E. bactérias coli OP50. Prepare várias placas com base no número de vermes necessários durante o ensaio. </li><li> Permitir-lhes a pôr ovos durante 6 horas e em seguida, usando um worm fio de platina picareta remover as mães. Verificar as placas sob o microscópio para avaliar o número de ovos postos. </li><li> Permitir que os ovos para chocar e crescer a 20 ° C durante 48 h. Neste momento, os animais estão em um L4 / estágio final adulto jovem. Escolha mesmos animais de palco e transferir para os poços contendo a solução PQ. Observação: Uma vez que 48 horas de incubação só se aplica aos mutantes que crescem de forma semelhante aos animais de tipo selvagem, que é importante monitorizar de desenvolvimentotaxa de mutações recentemente testados para garantir que está de acordo com a taxa de desenvolvimento de tipo selvagem, de outra forma, outras linhas de tempo deve ser utilizado. </li><li> Alternativamente, a utilização de técnicas de sincronização. Gerar população sincronizada de vermes larvas L1 utilizando solução de hipoclorito (25 ml de água, 125 ml de hipoclorito de sódio a 5,25%, 50 ml de NaOH 4 M; embrulhar garrafa com folha de alumínio para isolar da luz). No entanto, para este ensaio, não é recomendável, uma vez que o branqueamento intenso pode afectar o comportamento dos animais durante o ensaio. CUIDADO: Manusear solução de hipoclorito de acordo com as diretrizes. NOTA: Ao usar o RNAi para regular para baixo o gene de interesse, sincronizar os hermafroditas, como descrito na seção 2, com excepção da transferência das mães para placas de RNAi semeados com as bactérias específicas de RNAi. Quando o knockdown com o RNAi é fraca, recomenda alimentação para várias gerações. </li></ol> 3. Realização do Estresse Oxidativo Resistência Ensaio &lt;/ P&gt; <ol><li> Pipetar 40 ml da solução de 100 mM de PQ (preparada) a cada poço de uma placa de 96 poços. Utilize pelo menos 12 poços com réplicas de todas as condições (tratamento, mutante, etc.). Usando um verme picareta fio de platina, transferir 5-8 animais larvas L4 para cada bem indicando o horário de início e fim do tempo. </li><li> Ao iniciar uma outra condição, anote o horário de início e fim do tempo. Colocar a placa a 20 ° C no tempo de incubação entre transferindo os vermes e marcando animais mortos uma hora mais tarde a partir da hora de início. </li><li> Utilizando o microscópio de dissecação, a contagem de sobrevivência a cada hora. Agite ligeiramente a placa antes de iniciar a contagem. Indique vermes que não se movem, mesmo após avistar uma luz de alta intensidade, como animais mortos. Além disso, indique o número de animais vivos. NOTA: Olhando forma verme, caudas e movimento da cabeça em alta ampliação, ajudar a determinar de vermes mortos vivos. </li><li> Repita este passo a cada hora até que a maioria dos worms estão mortos. </li></ol> &lt;p class = &quot;jove_title&quot;&gt; 4. Determinação da Sobrevivência Percentagem em cada tempo de Ponto <ol><li> Calcular o número total de animais por estado somando o número total de animais transferidas para cada poço. Ignore os animais que estão danificados ou mortos após a transferência. </li><li> Para cada ponto de tempo, calcular o número total de animais mortos por condição (soma de animais mortos nos 12 poços). Para cada ponto de tempo, calcular a percentagem de morte (número de animais mortos, dividido pelo número total de animais e multiplicado por 100) e percentagem de sobrevivência (100 menos a morte por cento). </li><li> Repetir este ensaio pelo menos três vezes independentes. </li></ol>

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The authors declare that they have no competing financial interests.

C. elegans é um organismo modelo atractivo para estudar a resistência ao estresse oxidativo geneticamente in vivo, uma vez que podem ser facilmente cultivadas e rapidamente leva a um grande número de descendentes geneticamente idênticos. Vários métodos para medir a resistência de stress oxidativo têm sido anteriormente descrita e que se baseiam na suplementação de placas de cultura com várias fontes de ROS, como a PQ, rotenona, H 2 O 2, e juglona 25,26,29-32....

A reference was corrected in the publication of <a href="http://www.jove.com/video/52746">Measuring Oxidative Stress Resistance of Caenorhabditis elegans in 96-well Microtiter Plates</a>. There was an error with reference 34 in the Citations section. It has been updated from:
Allen, E., Walters, I.B., Hanahan, D. Brivanib a dual FGF/VEGF inhibitor,is active both first and second line againstmouse pancreatic neuroendocrine tumors developing adaptive/evasive resistance toVEGF inhibition. Clin Cancer Res. 17, (16) 5299-310 (2011).
to:
Allen, A. T., Maher, K. N., Wani, K. A., Betts, K. E., &#38; Chase, D. L. Coexpressed D1- and D2-like dopamine receptors antagonistically modulate acetylcholine release in Caenorhabditis elegans. Genetics. 188, 579-590 (2011).

Erratum: Measuring Oxidative Stress Resistance of Caenorhabditis elegans in 96-well Microtiter Plates

Em eucariotas, fosforilação oxidativa ocorrendo na cadeia de transporte de elétrons da mitocôndria é o principal motor da produção de energia na forma de ATP. Espécies reativas de oxigênio (ROS) são um subproduto natural do processo. Apesar do seu importante papel como moléculas de sinalização, excessiva de ROS pode levar a danos no ADN, carbonilação de proteínas, e a oxidação de lípidos. Um desequilíbrio entre a produção de ROS e desintoxicação faz com que o stress oxidativo, o que conduz à depleção da energia, lesão celular, e provoca a morte celular 1,2. O estresse oxidativo contribui para o envelhecimento e para o desenvolvimento de muitas doenças potencialmente fatais, incluindo câncer, diabetes, doenças cardiovasculares e neurodegenerativas 3-9. As células desenvolveram estratégias de defesa enzimáticos e não enzimáticos para manter os níveis de ROS adequadas e proteger os seus constituintes contra dano oxidativo 1,2. Superóxido dismutase (SOD) enzimas agem primeiro a convert superóxido a H 2 O 2, que é posteriormente convertida em água pela catalase ou enzimas peroxidase. Estratégias de defesa não enzimáticas incluem principalmente moléculas que reagem mais rapidamente com ROS, em comparação com macromoléculas celulares, protegendo os componentes celulares essenciais. Apesar do papel protetor da ROS desintoxicação enzimas, algumas moléculas ROS escapar dos mecanismos de defesa antioxidante e levar a danos oxidativos. Detecção, reparação e degradação dos componentes celulares danificados são estratégias essenciais da defesa durante o estresse oxidativo 1,2. Vias de sinalização envolvidas na resistência ao estresse e estresse oxidativo especificamente são altamente evolutivamente conservada 10,11. Ao contrário de experimentos de cultura de células, onde as condições organismal são apenas parcialmente reproduzido, o estudo do estresse oxidativo em organismos modelo 12,13 tem um grande significado. C. elegans é um nematóide de vida livre que pode ser fácil e barata cultured em um gramado bacteriana no meio de ágar. É pequeno no tamanho (cerca de 1 mm de comprimento) e, normalmente, cresce como um hermafrodita auto-fertilizar, o que facilita as manipulações genéticas. Tem um ciclo de vida rápido e uma alta capacidade reprodutiva, produzindo cerca de 300 descendentes por geração, tornando-se uma ferramenta poderosa para executar telas genéticos de larga escala 14. A C. elegans genoma está completamente sequenciado e 40-50% dos genes é previsível que sejam homólogos de genes associados a doenças humanas 15-18. O knockdown de genes de interesse utilizando RNAi é rápida e fácil em C. elegans. Gene para baixo regulamento poderia ser alcançado através da alimentação de animais a E. bactérias coli que abrigam um plasmídeo que expressa o ARN de cadeia dupla que tem como alvo o mRNA de interesse 19. Portanto, a determinação da função do gene usando telas de RNAi em grande escala tem um grande impacto na compreensão das doenças humanas, incluindo câncer 20,21. Estudos de Oresistência ao estresse xidative em C. elegans levaram à identificação de mecanismos conservadas de resistência ao stress oxidativo 13,22. Algumas vias são identificadas vias comuns que modulam a longevidade e resistência a outros tipos de stress, bem como a hipóxia, calor, e stress osmótico. Estas vias incluem a sinalização de insulina, a sinalização TOR, e autofagia. Outras vias importantes envolvem desintoxicação de ROS como enzimas superóxido dismutase e enzimas catalase, ou na reparação de danos, tais como proteínas de choque térmico e acompanhar 11,13,22. Este protocolo descreve como para determinar a resistência ao stress oxidativo de C. elegans em líquido. Nós usamos flcn-1 (ok975) e animais de tipo selvagem para demonstrar o protocolo já que mostramos anteriormente um aumento da resistência ao estresse oxidativo após a perda de flcn-1 (ok975) em C. elegans 23. Também mostraram que este aumento da resistência dependeem AMPK e autofagia, um eixo de sinalização que melhora bioenergética celular e promove a resistência ao estresse 23. PQ é um estressor oxidativo que interfere com a cadeia de transporte de elétrons para produzir espécies reativas de oxigênio 24. O mesmo ensaio pode ser adaptado e outras fontes de ROS ou compostos que geram ROS poderia ser utilizado tal como H 2 O 2 e rotenona. Ensaios semelhantes foram desenvolvidas em placas onde as baixas concentrações de PQ são utilizados 25,26. A vantagem deste teste é que ele é muito rápido, e os resultados podem ser obtidos em apenas um dia. Além disso, o volume total de líquido utilizado para realizar o ensaio de resistência ao estresse oxidativo em placas de 96 poços é baixo quando comparado com o volume utilizado para preparar-PQ contendo placas. Portanto, a quantidade de PQ usado é no ensaio de líquido é baixa, o que torna o ensaio pouco dispendioso e limita a produção de resíduos tóxicos. No entanto, limitações deste ensaio em comparação com ensaios em placa incluem o lack de alimento no líquido de ensaio e a menor concentração de oxigénio no líquido, em comparação com o ar. Estes são factores importantes que, em alguns casos, podem influenciar os resultados. Portanto, confirmando a reprodutibilidade utilizando outros métodos de resistência ao estresse oxidativo é recomendado para suportar os resultados obtidos neste ensaio.

<table><tbody><tr><td>Agar bacteriological grade</td><td>Multicell</td><td>800-010-LG</td><td></td></tr><tr><td>Bacteriological peptone</td><td>Oxoid</td><td>LP0037</td><td></td></tr><tr><td>Sodium chloride biotechnology grade</td><td>Bioshop</td><td>7647-14-5</td><td></td></tr><tr><td>Cholesterol</td><td>Sigma</td><td>C8503-25G</td><td></td></tr><tr><td>UltraPure tris hydrochloride</td><td>Invitrogen</td><td>15506-017</td><td></td></tr><tr><td>Tris aminomethane</td><td>Bio Basic Canada Inc</td><td>77-86-1</td><td></td></tr><tr><td>IPTG</td><td>Santa Cruz Biotechnology</td><td>sc-202185A</td><td></td></tr><tr><td>Ampicillin</td><td>Bioshop</td><td>69-52-3</td><td></td></tr><tr><td>Yeast extract</td><td>Bio Basic Inc.</td><td>8013-01-2</td><td></td></tr><tr><td>Methyl viologen dichloride hydrate</td><td>Aldrich chemistry</td><td>856177-1G</td><td></td></tr><tr><td>Petri dish 60 x15 mm</td><td>Fisher</td><td>FB0875713A</td><td></td></tr><tr><td>Pipet 10 ml</td><td>Fisher</td><td>1367520</td><td></td></tr><tr><td>Potassium phosphate monobasic</td><td>G-Biosciences</td><td>RC-084</td><td></td></tr><tr><td>Magnesium sulfate heptahydrate</td><td>Sigma</td><td>M-5921</td><td></td></tr><tr><td>Sodium phosphate dibasic</td><td>Bioshop</td><td>7558-79-4</td><td></td></tr><tr><td>Discovery v8 stereo zeiss microscope</td><td></td><td></td><td></td></tr><tr><td>96 well clear microtiter plate</td><td></td><td></td><td></td></tr><tr><td>&lt;em&gt;flcn-1&lt;/em&gt; RNAi source</td><td>Ahringer Library</td><td></td><td></td></tr></tbody></table>

measuring oxidative stress resistance of caenorhabditis elegans in 96-well microtiter plates

O stress oxidativo, que é o resultado de um desequilíbrio entre a produção e a desintoxicação de espécies reactivas de oxigénio, é um dos principais contribuintes para doenças humanas crónicas, incluindo doenças cardiovasculares e neurodegenerativas, diabetes, envelhecimento e cancro. Portanto, é importante para estudar o stress oxidativo, não só em sistemas de células, mas também utilizando organismos inteiros. C. elegans é um organismo modelo atraente para estudar a genética de vias de transdução de sinal de estresse oxidativo, que são altamente conservadas evolutivamente. Aqui, nós fornecemos um protocolo para medir a resistência ao estresse oxidativo em C. elegans em líquido. Reagentes Resumidamente, ROS-indutores, tais como paraquato (PQ) e H 2 O 2 são dissolvidos em tampão M9, e soluções são aliquotadas em cavidades de uma placa de microtitulação de 96 poços. L4 sincronizado / adulto jovem C. elegans animais são transferidos para os poços (5-8 animais / poço) e é medida a sobrevivênciaa cada hora até que a maioria dos worms estão mortos. Ao realizar um ensaio de resistência ao estresse oxidativo utilizando uma baixa concentração de estressores em placas, o envelhecimento pode influenciar o comportamento dos animais sobre o estresse oxidativo, o que poderia levar a uma interpretação incorrecta dos dados. No entanto, no ensaio aqui descrito, este problema é improvável de ocorrer uma vez que apenas L4 / animais adultos, jovens estão sendo usados. Além disso, este protocolo é barato e resultados são obtidos em um dia, o que torna esta técnica atraente para telas genéticos. No geral, isso irá ajudar a compreender vias de transdução de sinal de estresse oxidativo, que poderia ser traduzido em melhor caracterização de doenças humanas associadas a estresse oxidativo.

Comparando-tipo selvagem C. elegans para flcn-1 (ok975) animais mutantes Aqui utilizou-se 100 mM de PQ para determinar a resistência de tipo selvagem C. elegans animais em comparação com flcn-1 (ok975), que foi mostrado para resistir ao estresse oxidativo, calor e anoxia 23. Após 4 h de tratamento, 48,3% da do tipo selvagem sobreviveram, em comparação com 77,8% de sobrevivência em-um (flcn ok975) animais. Como esperado, flcn-...

Watch this Scientific Journal Video about Measuring Oxidative Stress Resistance of Caenorhabditis elegans in 96-well Microtiter Plates at JoVE.com

Measuring Oxidative Stress Resistance of Caenorhabditis elegans in 96-well Microtiter Plates

C. elegans is an attractive model organism to study signal transduction pathways involved in oxidative stress resistance. Here we provide a protocol to measure oxidative stress resistance of C. elegans animals in liquid phase, using several oxidizing agents in 96 well plates.

Medição de resistência de Estresse Oxidativo<em&gt; Caenorhabditis elegans</em&gt; Em placas de 96 poços de microtitulação

Oxidative stress, which is the result of an imbalance between production and detoxification of reactive oxygen species, is a major contributor to chronic ...

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Research

JoVE Journal

Biology

Measuring Oxidative Stress Resistance of Caenorhabditis elegans in 96-well Microtiter Plates

15.5K visualizações.  McGill University. C. elegans is an attractive model organism to study signal transduction pathways involved in oxidative stress resistance. Here we provide a protocol to measure oxidative stress resistance of C. elegans animals in liquid phase, using several oxidizing agents in 96 well plates. 

Vídeo: Measuring Oxidative Stress Resistance of Caenorhabditis elegans in 96-well Microtiter Plates

A Simple Method for High Throughput Chemical Screening in Caenorhabditis Elegans

Caenorhabditis elegans is a useful organism for testing chemical effects on physiology. Whole organism small molecule screens offer significant advantages for identifying biologically active chemical structures that can modify complex phenotypes such as lifespan. Described here is a simple protocol for producing hundreds of 96-well culture plates with fairly consistent numbers of C. elegans in each well. Next, we specified how to use these cultures to screen thousands of chemicals for effects on the lifespan of the nematode C. elegans. This protocol makes use of temperature sensitive sterile strains, agar plate conditions, and simple animal handling to facilitate the rapid and high throughput production of synchronized animal cultures for screening.

A Simple Method for High Throughput Chemical Screening in Caenorhabditis Elegans

Here we describe a simple protocol for rapidly producing hundreds of nematode growth media agar, 96-well culture plates with consistent numbers of Caenorhhabditis elegans per well. These cultures are useful for the phenotypic screening of whole organisms. We focus here on using these cultures to screen chemicals for pro-longevity effects.

Um método simples para High Throughput Screening químico em Caenorhabditis Elegans

Caenorhabditis elegans is a useful organism for testing chemical effects on physiology. Whole organism small molecule screens offer significant advantages ...

Bioquímica

Plate-based Large-scale Cultivation of Caenorhabditis elegans: Sample Preparation for the Study of Metabolic Alterations in Diabetes

Culturing Caenorhabditis elegans (C. elegans) in a large-scale manner on agar plates can be time-consuming and difficult. This protocol describes a simple and inexpensive method to obtain a large number of animals for the isolation of proteins to proceed with a western blot, mass spectrometry, or further proteomics analyses. Furthermore, an increase of nematode numbers for immunostainings and the integration of multiple analyses under the same culturing conditions can easily be achieved. Additionally, a transfer between plates with different experimental conditions is facilitated. Common techniques in plate culture involve the transfer of a single C. elegans using a platinum wire and the transfer of populated agar chunks using a scalpel. However, with increasing nematode numbers, these techniques become overly time-consuming. This protocol describes the large-scale culture of C. elegans including numerous steps to minimize the impact of the sample preparation on the physiology of the worm. Fluid and shear stress can alter the lifespan of and metabolic processes in C. elegans, thus requiring a detailed description of the critical steps in order to retrieve reliable and reproducible results. C. elegans is a model organism, consisting of neuronal cells for up to one-third, but lacking blood vessels, thus providing the possibility to investigate solely neuronal alterations independent of vascular control. Recently, early neurodegeneration in diabetic retinopathy was found prior to vascular alterations. Thus, C. elegans is of special interest for studying general mechanisms of diabetic complications. For example, an increased formation of advanced glycation end products (AGEs) and reactive oxygen species (ROS) is observed, which are reproducibly found in C. elegans. Protocols to handle samples of adequate size for a broader spectrum of investigations are presented here, exemplified by the study of diabetes-induced biochemical alterations. In general, this protocol can be useful for studies requiring large C. elegans numbers and in which liquid culture is not suitable.

Plate-based Large-scale Cultivation of Caenorhabditis elegans: Sample Preparation for the Study of Metabolic Alterations in Diabetes

This protocol describes a method for the large-scale cultivation of Caenorhabditis elegans on solid media. As an alternative to liquid culture, this protocol allows obtaining parameters of different scales under plate-based cultivation. This increases the comparability of results by omitting the morphological and metabolic differences between liquid and solid media culture.

Baseados na placa de cultivo em grande escala de Caenorhabditis elegans: preparação da amostra para o estudo de alterações metabólicas em Diabetes

Culturing Caenorhabditis elegans (C. elegans) in a large-scale manner on agar plates can be time-consuming and difficult. This protocol describes a simple ...

Surveying Low-Cost Methods to Measure Lifespan and Healthspan in Caenorhabditis elegans

The discovery and development of Caenorhabditis elegans as a model organism was influential in biology, particularly in the field of aging. Many historical and contemporary studies have identified thousands of lifespan-altering paradigms, including genetic mutations, transgenic gene expression, and hormesis, a beneficial, low-grade exposure to stress. With its many advantages, including a short lifespan, easy and low-cost maintenance, and fully sequenced genome with homology to almost two-thirds of all human genes, C. elegans has quickly been adopted as an outstanding model for stress and aging biology. Here, several standardized methods are surveyed for measuring lifespan and healthspan that can be easily adapted into almost any research environment, especially those with limited equipment and funds. The incredible utility of C. elegans is featured, highlighting the capacity to perform powerful genetic analyses in aging biology without the necessity of extensive infrastructure. Finally, the limitations of each analysis and alternative approaches are discussed for consideration.

Surveying Low-Cost Methods to Measure Lifespan and Healthspan in Caenorhabditis elegans

Caenorhabditis elegans serve as an excellent model system with robust and low-cost methods for surveying healthspan, lifespan, and resilience to stress.

Pesquisando métodos de baixo custo para medir a expectativa de vida e a saúde em Caenorhabditis elegans

The discovery and development of Caenorhabditis elegans as a model organism was influential in biology, particularly in the field of aging. Many ...

Genética

Studying Oxidative Stress Caused by the Mitis Group Streptococci in Caenorhabditis elegans

Caenorhabditis elegans (C. elegans), a free-living nematode, has emerged as an attractive model to study host-pathogen interactions. The presented protocol uses this model to determine the pathogenicity caused by the mitis group streptococci via the production of H2O2. The mitis group streptococci are an emerging threat that cause many human diseases such as bacteremia, endocarditis, and orbital cellulitis. Described here is a protocol to determine the survival of these worms in response to H2O2 produced by this group of pathogens. Using the gene skn-1 encoding for an oxidative stress response transcription factor, it is shown that this model is important for identifying host genes that are essential against streptococcal infection. Furthermore, it is shown that activation of the oxidative stress response can be monitored in the presence of these pathogens using a transgenic reporter worm strain, in which SKN-1 is fused to green fluorescent protein (GFP). These assays provide the opportunity to study the oxidative stress response to H2O2 derived by a biological source as opposed to exogenously added reactive oxygen species (ROS) sources.

Studying Oxidative Stress Caused by the Mitis Group Streptococci in Caenorhabditis elegans

The nematode Caenorhabditis elegans is an excellent model to dissect host-pathogen interactions. Described here is a protocol to infect the worm with members of the mitis group streptococci and determine activation of the oxidative stress response against H2O2 produced by this group of organisms.

Estudando estresse oxidativo causado pelo estreptococos grupo Mitis em Caenorhabditis elegans

Caenorhabditis elegans (C. elegans), a free-living nematode, has emerged as an attractive model to study host-pathogen interactions. The presented ...

Biologia do Desenvolvimento

Measuring Caenorhabditis elegans Life Span in 96 Well Microtiter Plates

Lifespan is a biological process regulated by several genetic pathways. One strategy to investigate the biology of aging is to study animals that harbor mutations in components of age-regulatory pathways. If these mutations perturb the function of the age-regulatory pathway and therefore alter the lifespan of the entire organism, they provide important mechanistic insights1-3.
Another strategy to investigate the regulation of lifespan is to use small molecules to perturb age-regulatory pathways. To date, a number of molecules are known to extend lifespan in various model organisms and are used as tools to study the biology of aging4-16. The number of molecules identified thus far is small compared to the genetic "toolset" that is available to study the biology of aging.
Caenorhabditis elegans is one of the principle models used to study aging because of its excellent genetics and short lifespan of three weeks. More recently, C.elegans has emerged as a model organism for phenotype based drug screens5,7,16-20 because of its small size and its ability to grow in microtiter plates.
Here we present an assay to measure C.elegans lifespan in 96 well microtiter plates. The assay was developed and successfully used to screen large libraries for molecules that extend C.elegans lifespan7. The reliability of the assay was evaluated in multiple tests: first, by measuring the lifespan of wild type animals grown at different temperatures; second, by measuring the lifespan of mutants with altered lifespans; third, by measuring changes in lifespan in response to different concentrations of the antidepressant Mirtazepine. Mirtazepine has previously been shown to extend lifespan in C.elegans7. The results of these tests show that the assay is able to replicate previous findings from other assays and is quantitative. The microtiter format also makes this lifespan assay compatible with automated liquid handling systems and allows integration into automated platforms.

Measuring Caenorhabditis elegans Life Span in 96 Well Microtiter Plates

In this protocol we present a method to measure Caenorhabditis elegans lifespan in 96 well microtiter plates.

Medição Caenorhabditis elegans Expectativa de Vida em 96 placas de microtitulação Bem

Lifespan is a biological process regulated by several genetic pathways. One strategy to investigate the biology of aging is to study animals that harbor ...

Biologia

Measurement of Oxygen Consumption Rates in Intact Caenorhabditis elegans

Optimal mitochondrial function is critical for healthy cellular activity, particularly in cells that have high energy demands like those in the nervous system and muscle. Consistent with this, mitochondrial dysfunction has been associated with a myriad of neurodegenerative diseases and aging in general. Caenorhabditis elegans have been a powerful model system for elucidating the many intricacies of mitochondrial function. Mitochondrial respiration is a strong indicator of mitochondrial function and recently developed respirometers offer a state-of-the-art platform to measure respiration in cells. In this protocol, we provide a technique to analyze live, intact C. elegans. This protocol spans a period of ~7 days and includes steps for (1) growing and synchronization of C. elegans, (2) preparation&#160;of compounds to be injected and hydration of probes, (3) drug loading and cartridge equilibration, (4) preparation of worm assay plate and assay run, and (5) post-experiment data analysis.

Measurement of Oxygen Consumption Rates in Intact Caenorhabditis elegans

Mitochondrial respiration is critical for organismal survival; therefore, oxygen consumption rate is an excellent indicator of mitochondrial health. In this protocol, we describe the use of a commercially available respirometer to measure basal and maximal oxygen consumption rates in live, intact, and freely-motile Caenorhabditis elegans.

Medição das taxas de consumo de oxigênio em intacta Caenorhabditis elegans

Optimal mitochondrial function is critical for healthy cellular activity, particularly in cells that have high energy demands like those in the nervous ...

Measurements of Physiological Stress Responses in C. Elegans

Organisms are often exposed to fluctuating environments and changes in intracellular homeostasis, which can have detrimental effects on their proteome and physiology. Thus, organisms have evolved targeted and specific stress responses dedicated to repair damage and maintain homeostasis. These mechanisms include the unfolded protein response of the endoplasmic reticulum (UPRER), the unfolded protein response of the mitochondria (UPRMT), the heat shock response (HSR), and the oxidative stress response (OxSR). The protocols presented here describe methods to detect and characterize the activation of these pathways and their physiological consequences in the nematode, C. elegans. First, the use of pathway-specific fluorescent transcriptional reporters is described for rapid cellular characterization, drug screening, or large-scale genetic screening (e.g., RNAi or mutant libraries). In addition, complementary, robust physiological assays are described, which can be used to directly assess sensitivity of animals to specific stressors, serving as functional validation of the transcriptional reporters. Together, these methods allow for rapid characterization of the cellular and physiological effects of internal and external proteotoxic perturbations.

Measurements of Physiological Stress Responses in C. Elegans

Here, we characterize cellular proteotoxic stress responses in the nematode C. elegans by measuring the activation of fluorescent transcriptional reporters and assaying sensitivity to physiological stress.

Medições de Respostas de Estresse Fisiológico em C. Elegans

Organisms are often exposed to fluctuating environments and changes in intracellular homeostasis, which can have detrimental effects on their proteome and ...

Quantifying Tissue-Specific Proteostatic Decline in Caenorhabditis elegans

The ability to maintain proper function and folding of the proteome (protein homeostasis) declines during normal aging, facilitating the onset of a growing number of age-associated diseases. For instance, proteins with polyglutamine expansions are prone to aggregation, as exemplified with the huntingtin protein and concomitant onset of Huntington&#8217;s disease. The age-associated deterioration of the proteome has been widely studied through the use of transgenic Caenorhabditis elegans expressing polyQ repeats fused to a yellow fluorescent protein (YFP). This polyQ::YFP transgenic animal model facilitates the direct quantification of the age-associated decline of the proteome through imaging the progressive formation of fluorescent foci (i.e., protein aggregates) and subsequent onset of locomotion defects that develop as a result of the collapse of the proteome. Further, the expression of the polyQ::YFP transgene can be driven by tissue-specific promoters, allowing the assessment of proteostasis across tissues in the context of an intact multicellular organism. This model is highly amenable to genetic analysis, thus providing an approach to quantify aging that is complementary to lifespan assays. We describe how to accurately measure polyQ::YFP foci formation within either neurons or body wall muscle during aging, and the subsequent onset of behavioral defects. Next, we highlight how these approaches can be adapted for higher throughput, and potential future applications using other emerging strategies for C. elegans genetic analysis.

Quantifying Tissue-Specific Proteostatic Decline in Caenorhabditis elegans

Proteostatic decline is a hallmark of aging, facilitating the onset of neurodegenerative diseases. We outline a protocol to quantifiably measure proteostasis in two different Caenorhabditis elegans tissues through heterologous expression of polyglutamine repeats fused to a fluorescent reporter. This model allows rapid in vivo genetic analysis of proteostasis.

Quantificando o declínio proteostático específico do tecido em elegans caenorhabditis

The ability to maintain proper function and folding of the proteome (protein homeostasis) declines during normal aging, facilitating the onset of a ...

High-Throughput Screening of Microbial Isolates with Impact on Caenorhabditis elegans Health

With its small size, short lifespan, and easy genetics, Caenorhabditis elegans offers a convenient platform to study the impact of microbial isolates on host physiology. It also fluoresces in blue when dying, providing a convenient means of pinpointing death. This property has been exploited to develop high-throughput label-free C. elegans survival assays (LFASS). These involve time-lapse fluorescence recording of worm populations set in multiwell plates, from which population median time of death can be derived. The present study adopts the LFASS approach to screen multiple microbial isolates at once for the effects on C. elegans susceptibility to severe heat and oxidative stresses. Such microbial screening pipeline, which can notably be used to prescreen probiotics, using severe stress resistance as a proxy for host health is reported here. The protocol describes how to grow both C. elegans gut microbiota isolate collections and synchronous worm populations in multiwell arrays before combining them for the assays. The example provided covers the testing of 47 bacterial isolates and one control strain on two worm strains, in two stress assays in parallel. However, the approach pipeline is readily scalable and applicable to the screening of many other modalities. Thus, it provides a versatile setup to rapidly survey a multiparametric landscape of biological and biochemical conditions that impact C. elegans health.

High-Throughput Screening of Microbial Isolates with Impact on Caenorhabditis elegans Health

Gut microbes may positively or negatively impact the health of their host via specific or conserved mechanisms. Caenorhabditis elegans is a convenient platform to screen for such microbes. The present protocol describes high-throughput screening of 48 bacterial isolates for impact on nematode stress resistance, used as a proxy for worm health.

Triagem de alto rendimento de isolados microbianos com impacto na saúde de Caenorhabditis elegans

With its small size, short lifespan, and easy genetics, Caenorhabditis elegans offers a convenient platform to study the impact of microbial isolates on ...

C. elegans Survival Assay: A Short-Term Toxicity Test

Source: Possik, E. and Pause, A. <a href="https://www.jove.com/video/2496/measuring-caenorhabditis-elegans-life-span-96-well-microtiter">Measuring Oxidative Stress Resistance of&#160;Caenorhabditis elegans&#160;in 96-well Microtiter Plates.</a>&#160;J. Vis. Exp. (2015).
This video introduces a short-term survival assay that tests a treatment for acute toxicity or tests a genetic strain for resistance to a toxic condition.&#160; The example protocol shows an example survival assay in which worms are tested for their ability to&#160; resist oxidative stress induced by paraquat (PQ).

C. elegans Ensaio de sobrevivência: um teste de toxicidade de curto prazo

Source: Possik, E. and Pause, A. Measuring Oxidative Stress Resistance of&#160;Caenorhabditis elegans&#160;in 96-well Microtiter Plates.&#160;J. Vis. Exp. ...

Medição de resistência de Estresse Oxidativo

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