Gostaríamos de agradecer a Jonathan Cooper Lab no Fred Hutchinson Cancer Research Center for a permissão para usar seu criostato. Este trabalho foi financiado pelo NIH e do WM Keck Foundation. BM é um Gordon e Betty Moore companheiro de Vida Fundação de Pesquisa Científica. Somos gratos a Daniel Gottschling para compartilhar seu protocolo de fixação com a gente.

1. Fixação de comunidades de leveduras <ol><li> Crescer comunidades de leveduras em um filtro de membrana (por exemplo, Millipore MF filtro de membrana; Figura 2A). Este protocolo corresponde a uma comunidade típico inferior a 2x10 8 células sobre um filtro de membrana de 6 mm de diâmetro. </li><li> Utilizar um pedaço de papel Whatman 541 filtro para cobrir o fundo de um 1 cm de diâmetro bem (Figura 2B). Este papel Whatman será usado como um transportador para transferir a comunidade em fases posteriores. Adicionar 1 ml de metanol a 100% para o poço, e deixar o bem em -20 ° C para a temperatura equilibrar. </li><li> Coloque N2 líquido num dewar. Congelar comunidade em nitrogênio líquido por imersão a comunidade por pelo menos 15 segundos em N2 líquido usando uma pinça (Figura 2C). </li><li> Transferir comunidade congelado para o bem de -20 ° C de metanol (Figura 2D). Garantir que a comunidade seja mantido na horizontal quando submergindo-o no metanol.Espere 20 min. O filtro de membrana de MF começa a desintegrar-se em metanol. </li><li> Transferir comunidade usando o transportador 541 de papel de filtro Whatman partir do metanol bem para uma placa de Petri frio manteve a -20 ° C para a evaporação de metanol (Figura 2E). Ao transferir, manter a comunidade no topo da transportadora Whatman filtro e afastar gotas extras de metanol usando outro pedaço de papel Whatman grossa antes de colocar a placa de Petri frio. Isto irá assegurar que o tempo de evaporação é consistente de amostra para amostra. </li><li> Espere 4-6 horas para a evaporação até que o transportador de filtro Whatman parece seca. Evaporação insuficiente deixa metanol residual que interfere com o corte. Excesso de secagem causas rachaduras e deformações nas comunidades. </li><li> Tome o exemplo de -20 ° C congelador. Corte o papel Whatman 541 filtro não cobertos pela comunidade. </li><li> Fazer um contentor rectangular de folha de alumínio-cúbico que é suficientemente grande tal que a amostra possui pelo menos 2 mm ~ margem decada um dos lados (Figura 2F). Coloque a comunidade sobre a superfície do fundo do recipiente de folha de alumínio; cobrir imediatamente a amostra com OCT para 3 ~ 4 mm acima altura comunidade. Se importante, a orientação da amostra pode ser ajustada neste passo em relação aos lados do recipiente. Esperar 10 min. </li><li> Coloque a amostra outubro embutida em uma placa metálica em gelo seco para congelar. Armazenar as comunidades congelados a -20 ° C ou -80 ° C congelador. </li></ol> 2. Seccionamento Comunidades congelada por Fluorescência de imagem <ol><li> Ajuste a temperatura da câmara de criocorte para -25 ° C e deixar as amostras na câmara até que a sua temperatura atinge a temperatura da câmara. </li><li> Monte a amostra para um crio-montagem após a aplicação de uma gota de outubro no monte. Espalhe outubro uniformemente sobre o lado da amostra com papel de filtro Whatman exposto (fundo do recipiente), de modo que a espessura da OCT é de 2-3 mm. Vamos congelar outubro dentro da câmara antes de se criostatoctioning. Assegurar uma margem de outubro de 2-3 mm em todos os lados da amostra de ajuda a preservar a integridade das secções. </li><li> Os lados do bloco de amostras de outubro pode ser usada para alinhar a amostra. Se a amostra não está alinhada em relação à lâmina, seccionando vai começar a partir de um canto ou lado da amostra. Regular a montagem para assegurar que a lâmina corta um rosto perfeitamente vertical (ou horizontal) do bloco de amostra. </li><li> Seções típicas para comunidades de leveduras são ~ 14 um de espessura. Após o corte de uma secção, a utilizar uma lâmina de microscópio mantido à temperatura ambiente para recolher a secção, pelo que se aproximava lentamente a lâmina para o corte. A seção vai derreter e transferir para a lâmina de microscópio. Até 18 seções podem ser transferidos para um slide. </li><li> Armazenar as lâminas a baixas temperaturas, de preferência -20 ° C, antes da imagiologia. A perda de sinal é mínima quando mantidos durante uma semana a 4 ° C. Para sinal de fluorescência máxima, a imagem é de preferência feito imediatamente após o corte. </li></ol>

<ol>
	<li>Tolker-Nielsen, T., Molin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial+Organization+of+Microbial+Biofilm+Communities.">Spatial Organization of Microbial Biofilm Communities.</a> Microbial Ecology. 40 (2), 75-84 (2000).</li><li>Moller, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=+In+Situ+Gene+Expression+in+Mixed-Culture+Biofilms:+Evidence+of+Metabolic+Interactions+between+Community+Members."> In Situ Gene Expression in Mixed-Culture Biofilms: Evidence of Metabolic Interactions between Community Members.</a> Appl. Environ. Microbiol. 64 (2), 721-732 (1998).</li><li>Lepp, P. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methanogenic+Archaea+and+human+periodontal+disease.">Methanogenic Archaea and human periodontal disease.</a> Proceedings of the National Academy of Sciences of the United States of America. 101 (16), 6176-6181 (2004).</li><li>V&#225;chov&#225;, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Architecture+of+developing+multicellular+yeast+colony:+spatio-temporal+expression+of+Ato1p+ammonium+exporter.">Architecture of developing multicellular yeast colony: spatio-temporal expression of Ato1p ammonium exporter.</a> Environmental Microbiology. 11 (7), 1866-1877 (2009).</li><li>Min&#225;rikov&#225;, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differentiated+Gene+Expression+in+Cells+within+Yeast+Colonies.">Differentiated Gene Expression in Cells within Yeast Colonies.</a> Experimental Cell Research. 271 (2), 296-304 (2001).</li><li>Shou, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthetic+cooperation+in+engineered+yeast+populations.">Synthetic cooperation in engineered yeast populations.</a> Proc. Natl. Acad. Sci. U.S.A. 104, 1877-1882 (2007).</li><li>Momeni, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cooperation+generates+a+unique+spatial+signature+in+microbial+communities.">Cooperation generates a unique spatial signature in microbial communities.</a> , (2012).</li><li>Kiernan, J., ed, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Histological and Histochemical Methods: Theory and Practice. , 4 (2008).</li><li>Piccirillo, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Rim101p/PacC+Pathway+and+Alkaline+pH+Regulate+Pattern+Formation+in+Yeast+Colonies.">The Rim101p/PacC Pathway and Alkaline pH Regulate Pattern Formation in Yeast Colonies.</a> Genetics. 184 (3), 707-716 (2010).</li></ol>

Não há conflitos de interesse declarados.

O procedimento aqui apresentado oferece um modo para inspeccionar a estrutura interna das comunidades de leveduras. O passo de fixação faz com que o metanol colónia de levedura rígida 8 e preserva a integridade da colónia, no entanto, também provoca 8 encolhimento que devem ser tidos em conta na interpretação dos resultados. Se costuma ver em torno de 30% de encolhimento da altura de colônias de leveduras, em comparação com as colônias diretamente embutidos em outubro sem fixar 9.<...

<table border="1"><tbody><tr><td> Nome do reagente </td><td> Companhia </td><td> Número de catálogo </td><td> Comentários (opcional) </td></tr><tr><td> O metanol 100% </td><td> JT Baker </td><td> 9070-01 </td><td></td></tr><tr><td> Tissue-Tek Composto outubro </td><td> Andwin Científico </td><td> 4583 </td><td></td></tr><tr><td> Whatman Grau No. 541 Papel Filtro Quantitativo </td><td> Whatman </td><td> 1541-047 </td><td></td></tr><tr><td> Millipore-MF filtro de membrana </td><td> Millipore </td><td> HAWP04700 </td><td></td></tr><tr><td> Criostato </td><td> Leica </td><td> CM 1510 S </td><td></td></tr></tbody></table>

cryosectioning yeast communities for examining fluorescence patterns

Micróbios geralmente vivem em comunidades. A organização espacial das células dentro de uma comunidade é acreditado para impactar a sobrevivência e função da comunidade 1. Ópticos técnicas de seccionamento, incluindo microscopia confocal e de dois fótons, têm se mostrado útil para observar a organização espacial das comunidades de bactérias e archaea 2,3. Uma combinação de imagem confocal e seccionamento física de colónias de levedura revelou a organização interna de celas 4. No entanto, seccionamento óptico direto em microscópio confocal ou dois fótons foi apenas capaz de atingir algumas camadas de células profundas em colônias de leveduras. Esta limitação é provavelmente devido à dispersão de luz forte a partir de células de levedura 4. Aqui, apresentamos um método baseado na fixação e cryosectioning para obter uma distribuição espacial de células fluorescentes dentro de comunidades de Saccharomyces cerevisiae. Usamos metanol como agente fixadorpara preservar a distribuição espacial das células. Comunidades fixos são infiltradas com OCT composto, congelados, e cryosectioned num criostato. Imagens de fluorescência das seções revela que a organização interna das células fluorescentes dentro da comunidade. Exemplos de comunidades de leveduras consistindo em estirpes que expressam as proteínas de vermelho e verde fluorescente demonstrar as potencialidades do método cryosectioning para revelar a distribuição espacial de células fluorescentes, bem como a expressão de genes dentro de colónias de levedura 2,3. Mesmo que o foco tem sido sobre as comunidades de Saccharomyces cerevisiae, o mesmo método pode ser potencialmente aplicada a examinar outras comunidades microbianas.

Imagens de fluorescência de secções transversais verticais das comunidades de levedura contendo vermelho-verde e marcada com populações competitivos 6 são mostrados na Figura 3. Essas comunidades consistem em duas linhagens de levedura prototróficos e sua competição por recursos compartilhados, incluindo espaço, leva a colunar padrões 7, como mostrado em suas verticais transversais. As resoluções para baixo para uma única célula pode ser resolvido em secções transv...

Watch this Scientific Journal Video about Cryosectioning Yeast Communities for Examining Fluorescence Patterns at JoVE.com

Cryosectioning Yeast Communities for Examining Fluorescence Patterns

Nós apresentamos um protocolo para congelamento e cryosectioning comunidades de leveduras para observar padrões internos de células fluorescentes. O método baseia-se na fixação de metanol e OCT-incorporação de preservar a distribuição espacial das células sem inactivar proteínas fluorescentes dentro de uma comunidade.

Cryosectioning comunidades de leveduras para o exame de padrões de fluorescência

Microbes typically live  in communities. The spatial organization  of cells within a community is believed to impact the survival and function of the  ...

cryosectioning-yeast-communities-for-examining-fluorescence-patterns

Research

JoVE Journal

Biology

8.8K visualizações.  Fred Hutchinson Cancer Research Center. Nós apresentamos um protocolo para congelamento e cryosectioning comunidades de leveduras para observar padrões internos de células fluorescentes. O método baseia-se na fixação de metanol e OCT-incorporação de preservar a distribuição espacial das células sem inactivar proteínas fluorescentes dentro de uma comunidade.

Vídeo: Cryosectioning Yeast Communities for Examining Fluorescence Patterns

Flash Freezing and Cryosectioning E12.5 Mouse Brain

Demonstrated in this video are the techniques for flash freezing and sectioning embryonic brain tissue from mouse. Useful tips for using the cryostat are given, including troubleshooting methods that can be used while cutting to ensure that the resultant tissues sections are free of cracks and other distortions.

Flash Freezing e Cryosectioning E12.5 cérebro de camundongo

Biologia

Microbial Communities in Nature and Laboratory - Interview

Comunidades microbianas na Natureza e Laboratório - Entrevista

Biology of Microbial Communities  - Interview

Biologia de comunidades microbianas - Entrevista

A Microfluidic Device with Groove Patterns for Studying Cellular Behavior

We describe a microfluidic device with microgrooved patterns for studying cellular behavior. This microfluidic platform consists of a top fluidic channel and a bottom microgrooved substrate. To fabricate the microgrooved channels, a top poly(dimethylsiloxane) (PDMS) mold containing the impression of the microfluidic channels was aligned and bonded to a microgrooved substrate. Using this device, mouse fibroblast cells were immobilized and patterned within microgrooved substrates (25, 50, 75, and 100 &mu;m wide). To study apoptosis in a microfluidic device, media containing hydrogen peroxide, Annexin V, and propidium iodide was perfused into the fluidic channel for 2 hours. We found that cells exposed to the oxidative stress became apoptotic. These apoptotic cells were confirmed by Annexin V that bound to phosphatidylserine at the outer leaflet of the plasma membrane during the apoptosis process. Using this microfluidic device with microgrooved patterns, the apoptosis process was observed in real-time and analyzed by using an inverted microscope containing an incubation chamber (37&deg;C, 5% CO2). Therefore, this microfluidic device incorporated with microgrooved substrates could be useful for studying the cellular behavior and performing high-throughput drug screening.

We describe a protocol for the fabrication of microfluidic devices that can enable cell capture and culture. In this approach patterned microstructures such as grooves within microfluidic channels are used to create low shear stress regions within which cell can dock.

Um dispositivo micro com padrões Groove para estudar o comportamento celular

We describe a microfluidic device with microgrooved patterns for studying cellular behavior.  This microfluidic platform consists of a top fluidic channel ...

Time-lapse Imaging of Mitosis After siRNA Transfection

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and cellular content. Hallmark events of mitosis, such as chromosome movement, can be readily tracked on an individual cell basis using time-lapse fluorescence microscopy of mammalian cell lines expressing specific GFP-tagged proteins. In combination with RNAi-based depletion, this can be a powerful method for pinpointing the stage(s) of mitosis where defects occur after levels of a particular protein have been lowered. In this protocol, we present a basic method for assessing the effect of depleting a potential mitotic regulatory protein on the timing of mitosis. Cells are transfected with siRNA, placed in a stage-top incubation chamber, and imaged using an automated fluorescence microscope. We describe how to use software to set up a time-lapse experiment, how to process the image sequences to make either still-image montages or movies, and how to quantify and analyze the timing of mitotic stages using a cell-line expressing mCherry-tagged histone H2B. Finally, we discuss important considerations for designing a time-lapse experiment. This strategy is complementary to other approaches and offers the advantages of 1) sensitivity to changes in kinetics that might not be observed when looking at cells as a population and 2) analysis of mitosis without the need to synchronize the cell cycle using drug treatments. The visual information from such imaging experiments not only allows the sub-stages of mitosis to be assessed, but can also provide unexpected insight that would not be apparent from cell cycle analysis by FACS.

Here we describe a basic protocol to image and quantify the mitotic timing of live mammalian tissue culture cells after siRNA transfection.

Lapso de tempo de imagens de Mitose Depois de Transfection siRNA

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and ...

Examining the Conformational Dynamics of Membrane Proteins in situ with Site-directed Fluorescence Labeling

Two electrode voltage clamp electrophysiology (TEVC) is a powerful tool to investigate the mechanism of ion transport1 for a wide variety of membrane proteins including ion channels2, ion pumps3, and transporters4. Recent developments have combined site-specific fluorophore labeling alongside TEVC to 
concurrently examine the conformational dynamics at specific residues and function of these proteins on the surface of single cells.
We will describe a method to study the conformational dynamics of membrane proteins by simultaneously monitoring fluorescence and current changes using voltage-clamp fluorometry. This approach can be used to examine the molecular motion of membrane proteins site-specifically following cysteine replacement and site-directed fluorophore labeling5,6. Furthermore, this method provides an approach to determine distance constraints between specific residues7,8. 
This is achieved by selectively attaching donor and acceptor fluorophores to two mutated cysteine residues of interest.
In brief, these experiments are performed following functional expression of the desired protein on the surface of Xenopus leavis oocytes. The large surface area of these oocytes enables facile functional measurements and a robust fluorescence signal5. It is also possible to readily change the extracellular conditions such as pH, ligand or cations/anions, which can provide further information on the mechanism of membrane proteins4. Finally, recent developments 
have also enabled the manipulation of select internal ions following co-expression with a second protein9.
Our protocol is described in multiple parts. First, cysteine scanning mutagenesis proceeded by fluorophore labeling is completed at residues located at the interface of the transmembrane and extracellular domains. Subsequent experiments are designed to identify residues which demonstrate large changes in fluorescence intensity (&lt;5%)3 upon a conformational change of the protein. Second, these changes in fluorescence intensity are compared to the kinetic parameters of 
the membrane protein in order to correlate the conformational dynamics to the function of the protein10. This enables a rigorous biophysical analysis of the molecular motion of the target protein. Lastly, two residues of the holoenzyme can be labeled with a donor and acceptor fluorophore in order to determine distance constraints using donor photodestruction methods. It is also possible to monitor the relative movement of protein subunits following labeling with a donor and acceptor fluorophore.

Examining the Conformational Dynamics of Membrane Proteins in situ with Site-directed Fluorescence Labeling

We will describe a method which measures the kinetics of ion transport of membrane proteins alongside site-specific analysis of conformational changes using fluorescence on single cells. This technique is adaptable to ion channels, transporters and ion pumps and can be utilized to determine distance constraints between protein subunits.

Examinando o Dynamics Conformacional de Proteínas de Membrana In situ Com Labeling-Site dirigido Fluorescência

Two electrode voltage clamp electrophysiology (TEVC) is a powerful tool to investigate the mechanism of ion transport1 for a wide variety of membrane ...

A Fluorescence Microscopy Assay for Monitoring Mitophagy in the Yeast Saccharomyces cerevisiae

Autophagy is important for turnover of cellular components under a range of different conditions. It serves an essential homeostatic function as well as a quality control mechanism that can target and selectively degrade cellular material including organelles1-4. For example, damaged or redundant mitochondria (Fig. 1), not disposed of by autophagy, can represent a threat to cellular homeostasis and cell survival. In the yeast, Saccharomyces cerevisiae, nutrient deprivation (e.g., nitrogen starvation) or damage can promote selective turnover of mitochondria by autophagy in a process termed mitophagy 5-9.
We describe a simple fluorescence microscopy approach to assess autophagy. For clarity we restrict our description here to show how the approach can be used to monitor mitophagy in yeast cells. The assay makes use of a fluorescent reporter, Rosella, which is a dual-emission biosensor comprising a relatively pH-stable red fluorescent protein linked to a pH-sensitive green fluorescent protein. The operation of this reporter relies on differences in pH between the vacuole (pH ~ 5.0-5.5) and mitochondria (pH ~ 8.2) in living cells. Under growing conditions, wild type cells exhibit both red and green fluorescence distributed in a manner characteristic of the mitochondria. Fluorescence emission is not associated with the vacuole. When subjected to nitrogen starvation, a condition which induces mitophagy, in addition to red and green fluorescence labeling the mitochondria, cells exhibit the accumulation of red, but not green fluorescence, in the acidic vacuolar lumen representing the delivery of mitochondria to the vacuole. Scoring cells with red, but not green fluorescent vacuoles can be used as a measure of mitophagic activity in cells5,10-12.

A Fluorescence Microscopy Assay for Monitoring Mitophagy in the Yeast Saccharomyces cerevisiae

A robust approach to monitor the delivery of organelles to the acidic lumen of the yeast vacuole for degradation and recycling is described. The method relies on the specific labeling of target organelles with a genetically encoded dual-emission fluorescence pH-biosensor, and visualization of individual cells using fluorescence microscopy.

Um Ensaio de microscopia de fluorescência para Mitophagy Monitoramento no fermento Saccharomyces cerevisiae

Autophagy is important for turnover of cellular components under a range of different conditions. It serves an essential homeostatic function as well as a ...

Quantitative Live Cell Fluorescence-microscopy Analysis of Fission Yeast

Several microscopy techniques are available today that can detect a specific protein within the cell. During the last decade live cell imaging using fluorochromes like Green Fluorescent Protein (GFP) directly attached to the protein of interest has become increasingly popular 1. Using GFP and similar fluorochromes the subcellular localisations and movements of proteins can be detected in a fluorescent microscope. Moreover, also the subnuclear localisation of a certain region of a chromosome can be studied using this technique. GFP is fused to the Lac Repressor protein (LacR) and ectopically expressed in the cell where tandem repeats of the lacO sequence has been inserted into the region of interest on the chromosome2. The LacR-GFP will bind to the lacO repeats and that area of the genome will be visible as a green dot in the fluorescence microscope. Yeast is especially suited for this type of manipulation since homologous recombination is very efficient and thereby enables targeted integration of the lacO repeats and engineered fusion proteins with GFP 3. Here we describe a quantitative method for live cell analysis of fission yeast. Additional protocols for live cell analysis of fission yeast can be found, for example on how to make a movie of the meiotic chromosomal behaviour 4. In this particular experiment we focus on subnuclear organisation and how it is affected during gene induction. We have labelled a gene cluster, named Chr1, by the introduction of lacO binding sites in the vicinity of the genes. The gene cluster is enriched for genes that are induced early during nitrogen starvation of fission yeast 5. In the strain the nuclear membrane (NM) is labelled by the attachment of mCherry to the NM protein Cut11 giving rise to a red fluorescent signal. The Spindle Pole body (SPB) compound Sid4 is fused to Red Fluorescent Protein (Sid4-mRFP) 6. In vegetatively growing yeast cells the centromeres are always attached to the SPB that is embedded in the NM 7. The SPB is identified as a large round structure in the NM. By imaging before and 20 minutes after depletion of the nitrogen source we can determine the distance between the gene cluster (GFP) and the NM/SPB. The mean or median distances before and after nitrogen depletion are compared and we can thus quantify whether or not there is a shift in subcellular localisation of the gene cluster after nitrogen depletion.

The fission yeast, Schizosaccharomyces pombe, is a good model system to study basic cellular processes. Here we describe a method to perform quantitative live cell analysis of fission yeast. In this particular experiment we focus on organisation of the genome within the cell nucleus, but the method can also be used to study cytosolic factors.

Quantitativas de células vivas de Análise de microscopia de fluorescência de levedura

Several microscopy techniques are available today that can detect a specific protein within the cell. During the last decade live cell imaging using ...

Radioactive in situ Hybridization for Detecting Diverse Gene Expression Patterns in Tissue

Knowing the timing, level, cellular localization, and cell type that a gene is expressed in contributes to our understanding of the function of the gene. Each of these features can be accomplished with in situ hybridization to mRNAs within cells. Here we present a radioactive in situ hybridization method modified from Clayton et al. (1988)1 that has been working successfully in our lab for many years, especially for adult vertebrate brains2-5. The long complementary RNA (cRNA) probes to the target sequence allows for detection of low abundance transcripts6,7. Incorporation of radioactive nucleotides into the cRNA probes allows for further detection sensitivity of low abundance transcripts and quantitative analyses, either by light sensitive x-ray film or emulsion coated over the tissue. These detection methods provide a long-term record of target gene expression. Compared with non-radioactive probe methods, such as DIG-labeling, the radioactive probe hybridization method does not require multiple amplification steps using HRP-antibodies and/or TSA kit to detect low abundance transcripts. Therefore, this method provides a linear relation between signal intensity and targeted mRNA amounts for quantitative analysis. It allows processing 100-200 slides simultaneously. It works well for different developmental stages of embryos. Most developmental studies of gene expression use whole embryos and non-radioactive approaches8,9, in part because embryonic tissue is more fragile than adult tissue, with less cohesion between cells, making it difficult to see boundaries between cell populations with tissue sections. In contrast, our radioactive approach, due to the larger range of sensitivity, is able to obtain higher contrast in resolution of gene expression between tissue regions, making it easier to see boundaries between populations. Using this method, researchers could reveal the possible significance of a newly identified gene, and further predict the function of the gene of interest.

Radioactive in situ Hybridization for Detecting Diverse Gene Expression Patterns in Tissue

This protocol is successfully used to quantitatively detect levels and spatial patterns of mRNA expression in multiple tissue types across vertebrate species. The method can detect low abundance transcripts and allows processing of hundreds of slides simultaneously. We present this protocol using expression profiling of avian embryonic brain formation as an example.

Radioativo In situ Hibridação para detecção de padrões de expressão dos genes nos tecidos diversos

Knowing the timing, level, cellular localization, and cell type that a gene is expressed in contributes to our understanding of the function of the gene. ...

Acquiring Fluorescence Time-lapse Movies of Budding Yeast and Analyzing Single-cell Dynamics using GRAFTS

Fluorescence time-lapse microscopy has become a powerful tool in the study of many biological processes at the single-cell level. In particular, movies depicting the temporal dependence of gene expression provide insight into the dynamics of its regulation; however, there are many technical challenges to obtaining and analyzing fluorescence movies of single cells. We describe here a simple protocol using a commercially available microfluidic culture device to generate such data, and a MATLAB-based, graphical user interface (GUI) -based software package to quantify the fluorescence images. The software segments and tracks cells, enables the user to visually curate errors in the data, and automatically assigns lineage and division times. The GUI further analyzes the time series to produce whole cell traces as well as their first and second time derivatives. While the software was designed for S. cerevisiae, its modularity and versatility should allow it to serve as a platform for studying other cell types with few modifications.

We present a simple protocol to obtain fluorescence microscopy movies of growing yeast cells, and a GUI-based software package to extract single-cell time series data. The analysis includes automated lineage and division time assignment integrated with visual inspection and manual curation of tracked data.

Aquisição de fluorescência Filmes Time-lapse da levedura de brotamento e análise da dinâmica de células simples utilização de enxertos

Fluorescence time-lapse microscopy has become a powerful tool in the study of many biological processes at the single-cell level. In particular, movies ...