Die Autoren möchten Dr. Sheng Ding vom Scripps Research Institute und Dr. Hongkui Deng von der Peking-Universität für ihre Unterstützung und die Richtung zu danken.

1. Vorbereitung der MEF Feeder-Platten <ol><li> Einen Tag vor Kultivierung ES-Zellen, Tauwetter ein Fläschchen von bestrahlten E14.5 CF-1 MEF Feeder-Zellen (siehe unsere Vorgehensweise zum ES-Zellen auftauen). </li><li> Platte der MEF Feeder-Zellen bei einer Dichte von 10.000 Zellen / Well in einer 12-Well-Platte. Inkubieren Sie die Zellen über Nacht bei 37 ° C und 5% CO 2. MEF Zellen Medien: DMEM mit 10% ES-PBS, 1X Glutamin und 1X nicht-essentiellen Aminosäuren ergänzt. </li></ol> 2. Wartung von Self-Erneuerung der Maus ES-Zellen <ol><li> Lösen Sie die ES-Zellen unter Verwendung von Trypsin. Seed die Zellen bei einer Dichte von 50.000 Zellen / well auf die zuvor vorbereiteten MEF Feeder-Platten in Nährmedien (Knockout MEM mit 15% KSR, 4 mM L-Glutamin, 0,1 mM nicht-essentiellen Aminosäuren und 1X BME ergänzt) mit SC1 ergänzt in der gewünschten Konzentration (wir haben 100 nM, 300 nM und 1 pM). Außerdem haben wir eine positive Kontrolle gut, dass mit 1000 μ / ml LIF ergänzt wurde. Inkubieren Sie die Zellen über Nacht bei 37 ° C und 5% CO 2. </li><li> Kultur der Zellen bei 37 ° C und 5% CO 2 für 3-4 Tage in jedem Durchgang. Refresh Medien alle 48 Stunden. </li><li> Passage-Zellen von 1.10 bis 01.15 Uhr mit Trypsin ein ähnlicher Dichte wie die erste Aussaatdichte aufrecht zu erhalten. Nach 5 Passagen, können die Zellen auf die Expression von typischen Pluripotenz Marker mit Immunzytochemie untersucht werden. </li></ol> 3. Immunzytochemische Untersuchung der Pluripotenz Markers <ol><li> Waschen Sie die Zellen vorsichtig dreimal mit PBS. </li><li> Fix die Zellen mit 500 ul Fixativ für 20 Minuten bei Raumtemperatur. </li><li> Waschen Sie die Zellen vorsichtig dreimal mit PBS. </li><li> Block unspezifische Bindung mit 500 ul Blockierungspuffer für eine Stunde bei Raumtemperatur. </li><li> Inkubieren Sie die Zellen mit 250 ul des spezifischen primären Antikörper (wir Nanog, Sox2, SSEA1 und Oct4 bei den folgenden Verdünnungen: 1:500, 1:2000, 1:500 und 1:500) </li><li> Waschen Sie die Zellen vorsichtig dreimal mit PBS. </li><li> Inkubieren Sie die Zellen mit 250 ul des sekundären Antikörper für 2 Stunden bei Raumtemperatur, hielten sich fern von Licht (wir haben Esel anti-Maus konjugiert mit Alexa Fluor ® 555 bei 1:2000 und Esel-anti-Kaninchen konjugiert mit Alexa Fluor ® 488 bei 1 : 2000). </li><li> Waschen Sie die Zellen vorsichtig dreimal mit PBS. </li><li> Add DAPI (Endkonzentration 1 pg / ml) auf dem letzten Waschen und Inkubation 5 Minuten, um Kerne zu visualisieren. </li><li> Analysieren Sie die Zellen unter einem Fluoreszenzmikroskop. </li></ol> 4. Repräsentative Ergebnisse: 1. Morphologie Ergebnisse: Maus ES-Zellen (ESC R1) wurden am MEF Feeder-Zellen in Anwesenheit von entweder LIF oder SC1 gewachsen zu Selbst-Erneuerung in einem undifferenzierten Zustand halten. Nach dem zweiten Durchgang konnte die Differenzierung in Zellen ohne LIF oder SC1 (negative Kontrolle) beobachtet werden und nach 5 Passagen im Wesentlichen keine undifferenzierte Kolonien beobachtet wurden. LIF (positive Kontrolle) behandelt Kolonien blieb in einem undifferenzierten Zustand in den 5 Zellpassagen. Zellen, die mit SC1 in Konzentrationen von 300 nM oder 100 nM behandelt blieb auch nach 5 Passagen undifferenziert, aber die Zellen mit 1 uM SC1 erfahrenen Zelltod nach dem vierten Durchgang behandelt. (Bild 2 von app beachten) Tabelle 1 fasst die morphologische Beobachtungen. 2. Expression der Pluripotenz Markers Maus ES-Zellen für 5 Passagen beibehalten wurden fixiert und untersucht durch Immunzytochemie für SSEA1, Oct4, Nanog und Sox2. Marker-Expression wurde ähnlich wie Zellen in LIF erhalten. (Abb. 3 und 4 des app beachten) <img src="/files/ftp_upload/1550/1550fig2a.jpg" alt="Abbildung 1" /> Abbildung 1: Morphologie Vergleich von Zellen in LIF oder SC1 gepflegt. Kein Unterschied in der Morphologie beobachtet. <img src="/files/ftp_upload/1550/1550fig2c.jpg" alt="Abbildung 2 und 3" /> Abbildung 2 und Abbildung 3: Nanog, SSEA1, Sox2 und Oct4 Färbung von ES-Zellen mit SC1 oder LIF (Abb. 4 von ca. beachten) gepflegt. Cells in SC1 gepflegt zeigen ähnliche Pluripotenz-Marker zum Ausdruck Zellen in LIF erhalten. Tabelle 1 <table border="1" cellspacing="0" cellpadding="0"><tbody><tr><td></td><td> Negative Control </td><td> LIF Positive Control </td><td> SC1 1um </td><td> SC1 300 nM </td><td> SC1 100 nM </td></tr><tr><td> 1. Besuch </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td></tr><tr><td> 2. Passage </td><td> Einige differenzierte Morphologie </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td></tr><tr><td> 3. Passage </td><td> Mehrzahl der Zellen differenziert </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td></tr><tr><td> 4. Passage </td><td> Kein ESC Kolonien </td><td> Normale ES Zellmorphologie </td><td> Der Zelltod beobachtet </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td></tr><tr><td> 5th Passage </td><td> differenziert </td><td> Normale ES Zellmorphologie </td><td> Der Zelltod beobachtet </td><td> Normale ES Zellmorphologie </td><td> Normale ES Zellmorphologie </td></tr></tbody></table>

<ol>
	<li>Williams, R. L., Hilton, D. J., Pease, S., Willson, T. A., Stewart, C. L., Gearing, D. P., Wagner, E. F., Metcalf, D., Nicola, N. A., Gough, N. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myeloid+leukaemia+inhibitory+factor+maintains+the+developmental+potential+of+embryonic+stem+cells.">Myeloid leukaemia inhibitory factor maintains the developmental potential of embryonic stem cells.</a> Nature. 336, 684-687 (1988).</li><li>Ying, Q. L., Wray, J., Nichols, J., Batlle-Morera, L., Doble, B., Woodgett, J., Cohen, P., Smith, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+ground+state+of+embryonic+stem+cell+self-renewal.">The ground state of embryonic stem cell self-renewal.</a> Nature. 453, 519-523 (2008).</li><li>Chen, S., Do, J. T., Zhang, Q., Yao, S., Yan, F., Peters, E. C., Scholer, H. R., Schultz, P. G., Ding, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-renewal+of+embryonic+stem+cells+by+a+small+molecule.">Self-renewal of embryonic stem cells by a small molecule.</a> Proc. Natl. Acat. Sci. USA. 103, 17266-17271 (2006).</li></ol>

The authors of this article are employed by Stemgent that produces reagents and instruments used in this article.

Das kleine Molekül SC1 kann zur Selbst-Erneuerung mit einem undifferenzierten Zustand in Maus-ES-Zellen zu erhalten. Vor dem Einsatz auf einer ungeprüften Zelllinie, jedoch sollte es titriert auf die optimale Konzentration zu bestimmen. Zum Beispiel, testeten wir drei Konzentrationen auf der Maus-ES-Zelllinie ESC R1. 100 nM und 300 nM Konzentrationen konnten Maus-ES-Zellen zu erhalten, war jedoch ein 1 pM Konzentration giftig. SC1 kann auch unter Feeder-freien Bedingungen verwendet werden.

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		<th>Material Name</th>
		<th>Type</th>
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		<th>Catalogue Number</th>
		<th>Comment</th>
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<tr>
<td>SC1</td>
<td>&nbsp;</td>
<td>Stemgent</td>
<td>04-0011</td>
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<td>LIF</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>ESG1107</td>
<td>&nbsp;</td>
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<td>SSEA-1 antibody</td>
<td>&nbsp;</td>
<td>Santa Cruz</td>
<td>21702</td>
<td>&nbsp;</td>
<tr>
<td>Nanog antibody</td>
<td>&nbsp;</td>
<td>Abcam</td>
<td>ab21603</td>
<td>&nbsp;</td>
<tr>
<td>Sox2 antibody</td>
<td>&nbsp;</td>
<td>Chemicon</td>
<td>Ab5603</td>
<td>&nbsp;</td>
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<td>Oct4 antibody</td>
<td>&nbsp;</td>
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the use of sc1 (pluripotin) to support mesc self-renewal in the absence of lif

Maus embryonale Stammzellen (ES-Zellen) sind konventionell mit Leukämie Inhibitory Factor (LIF), um sich selbst zu erneuern pflegen kultiviert.<sup&gt; 1</sup&gt; Allerdings ist LIF teuer und Aktivierung der LIF/JAK/STAT3 Weg ist nicht unbedingt erforderlich, um die Selbst-Erneuerung Zustand zu halten.<sup&gt; 2</sup&gt; Die SC1 kleine Molekül kann eine kostengünstige Alternative zu LIF werden. SC1 Funktionen durch duale Hemmung des Ras-GAP und ERK1.<sup&gt; 3</sup&gt; Illustration seines Wirkmechanismus macht ihn zu einem nützlichen Werkzeug, um die grundlegenden molekularen Mechanismen der Selbst-Erneuerung zu studieren. Hier zeigen wir das Verfahren zur Kultivierung von Maus-ES-Zellen in Anwesenheit von SC1 und zeigen, dass sie in der Lage, sich selbst zu erneuern in der Abwesenheit von LIF zu halten sind. Zellen, die mit SC1 kultivierten zeigten ähnliche Morphologie im Vergleich zu Zellen mit LIF erhalten. Beide zeigten typische Maus-ES-Morphologie nach fünf Durchgängen. Expression von typischen Pluripotenz-Marker (Oct4, Sox2, Nanog und SSEA1) wurde nach fünf Durchgängen in Gegenwart von SC1 beobachtet. Darüber hinaus verursacht SC1 keine offenkundige Toxizität bei Maus-ES-Zellen.

Watch this Scientific Journal Video about The use of SC1 Pluripotin to Support mESC Self-renewal in the Absence of LIF at JoVE.com

The use of SC1 Pluripotin to Support mESC Self-renewal in the Absence of LIF

SC1 Funktionen durch duale Hemmung des Ras-GAP und ERK1. Wir testeten die Funktion von SC1 in Unterstützung von Maus ES-Zell-Selbst-Erneuerung in der Abwesenheit von LIF und zeigte, dass SC1 in der Lage, sich selbst zu erneuern von Maus-ES-Zellkulturen zu halten ist.

Die Verwendung von SC1 (Pluripotin) zu MESC Self-Erneuerung in der Abwesenheit von LIF-Support

Mouse embryonic stem (ES) cells are conventionally cultured with Leukemia Inhibitory Factor (LIF) to maintain self-renewal.1 However, LIF is expensive and ...

the-use-sc1-pluripotin-to-support-mesc-self-renewal-absence

Research

JoVE Journal

Biology

The use of SC1 (Pluripotin) to Support mESC Self-renewal in the Absence of LIF

10.4K Aufrufe.  Stemgent. SC1 Funktionen durch duale Hemmung des Ras-GAP und ERK1. Wir testeten die Funktion von SC1 in Unterstützung von Maus ES-Zell-Selbst-Erneuerung in der Abwesenheit von LIF und zeigte, dass SC1 in der Lage, sich selbst zu erneuern von Maus-ES-Zellkulturen zu halten ist.

Serie: The use of SC1 Pluripotin to Support mESC Self-renewal in the Absence of LIF

Use of the Protease Fluorescent Detection Kit to Determine Protease Activity

The Protease Fluorescent Detection Kit provides ready-to-use reagents for detecting the presence of protease activity. This simple assay to detect protease activity uses casein labeled with fluorescein isothiocyanate (FITC) as the substrate.
Protease activity results in the cleavage of the FITC-labeled casein substrate into smaller fragments, which do not precipitate under acidic conditions. After incubation of the protease sample and substrate, the reaction is acidified with the addition of trichloroacetic acid (TCA). The mixture is then centrifuged with the undigested substrate forming a pellet and the smaller, acid soluble fragments remaining in solution. The supernatant is neutralized and the fluorescence of the FITC-labeled fragments is measured.
The described kit procedure detects the trypsin protease control at a concentration of approximately 0.5 &mu;g/ml (5 ng of trypsin added to the assay). This sensitivity can be increased with a longer incubation time, up to 24 hours. The assay is performed in microcentrifuge tubes and procedures are provided for fluorescence detection using either cuvettes or multiwell plates.

The Protease Fluorescent Detection Kit is designed for the measurement of protease activity using fluorometry. It is also suitable for detection of trace amounts of protease contamination. The method is based on the proteolytic hydroysis of a proprietary formulation of a FITC-labeled casein substrate.

Die Nutzung der Protease Fluorescent Detection Kit für Protease-Aktivität zu bestimmen

The Protease Fluorescent Detection Kit provides ready-to-use reagents for detecting the presence of protease activity. This simple assay to detect ...

Forschung

Biologie

The use of Biofeedback in Clinical Virtual Reality: The INTREPID Project

Generalized anxiety disorder (GAD) is a psychiatric disorder characterized by a constant and unspecific anxiety that interferes with daily-life activities. Its high prevalence in general population and the severe limitations it causes, point out the necessity to find new efficient strategies to treat it. Together with the cognitive-behavioral treatments, relaxation represents a useful approach for the treatment of GAD, but it has the limitation that it is hard to be learned. The INTREPID project is aimed to implement a new instrument to treat anxiety-related disorders and to test its clinical efficacy in reducing anxiety-related symptoms. The innovation of this approach is the combination of virtual reality and biofeedback, so that the first one is directly modified by the output of the second one. In this way, the patient is made aware of his or her reactions through the modification of some features of the VR environment in real time. Using mental exercises the patient learns to control these physiological parameters and using the feedback provided by the virtual environment is able to gauge his or her success. The supplemental use of portable devices, such as PDA or smart-phones, allows the patient to perform at home, individually and autonomously, the same exercises experienced in therapist's office. The goal is to anchor the learned protocol in a real life context, so enhancing the patients' ability to deal with their symptoms. The expected result is a better and faster learning of relaxation techniques, and thus an increased effectiveness of the treatment if compared with traditional clinical protocols.

The Project on Virtual Reality Intelligent Multi-sensor System for the Treatment of Anxiety-related Disorders (INTREPID) is aimed at developing a multi-sensor context-aware virtual reality system for the treatment of anxiety-related disorders.

Der Einsatz von Biofeedback in der klinischen Virtual Reality: Die INTREPID Projekt

Generalized anxiety disorder (GAD) is a psychiatric disorder characterized by a constant and unspecific anxiety that interferes with daily-life ...

Quantification of &gamma;H2AX Foci in Response to Ionising Radiation

DNA double-strand breaks (DSBs), which are induced by either endogenous metabolic processes or by exogenous sources, are one of the most critical DNA lesions with respect to survival and preservation of genomic integrity. An early response to the induction of DSBs is phosphorylation of the H2A histone variant, H2AX, at the serine-139 residue, in the highly conserved C-terminal SQEY motif, forming &gamma;H2AX1. Following induction of DSBs, H2AX is rapidly phosphorylated by the phosphatidyl-inosito 3-kinase (PIKK) family of proteins, ataxia telangiectasia mutated (ATM), DNA-protein kinase catalytic subunit and ATM and RAD3-related (ATR)2. Typically, only a few base-pairs (bp) are implicated in a DSB, however, there is significant signal amplification, given the importance of chromatin modifications in DNA damage signalling and repair. Phosphorylation of H2AX mediated predominantly by ATM spreads to adjacent areas of chromatin, affecting approximately 0.03% of total cellular H2AX per DSB2,3. This corresponds to phosphorylation of approximately 2000 H2AX molecules spanning ~2 Mbp regions of chromatin surrounding the site of the DSB and results in the formation of discrete &gamma;H2AX foci which can be easily visualized and quantitated by immunofluorescence microscopy2. The loss of &gamma;H2AX at DSB reflects repair, however, there is some controversy as to what defines complete repair of DSBs; it has been proposed that rejoining of both strands of DNA is adequate however, it has also been suggested that re-instatement of the original chromatin state of compaction is necessary4-8. The disappearence of &gamma;H2AX involves at least in part, dephosphorylation by phosphatases, phosphatase 2A and phosphatase 4C5,6. Further, removal of &gamma;H2AX by redistribution involving histone exchange with H2A.Z has been implicated7,8. Importantly, the quantitative analysis of &gamma;H2AX foci has led to a wide range of applications in medical and nuclear research. Here, we demonstrate the most commonly used immunofluorescence method for evaluation of initial DNA damage by detection and quantitation of &gamma;H2AX foci in &gamma;-irradiated adherent human keratinocytes9.

Quantification of &amp;#947;H2AX Foci in Response to Ionising Radiation

Quantification of DNA double-strand streaks using &gamma;H2AX formation as a molecular marker has become an invaluable tool in radiation biology. Here we demonstrate the use of an immunofluorescence assay for quantification of &gamma;H2AX foci after exposure of cells to radiation.

Die Quantifizierung der γH2AX Foci in Response to ionisierender Strahlung

DNA double-strand breaks (DSBs), which are induced by either endogenous metabolic processes or by exogenous sources, are one of the most critical DNA ...

Oct4GiP Reporter Assay to Study Genes that Regulate Mouse Embryonic Stem Cell Maintenance and Self-renewal

Pluripotency and self-renewal are two defining characteristics of embryonic stem cells (ES cells). Understanding the underlying molecular mechanism will greatly facilitate the use of ES cells for developmental biology studies, disease modeling, drug discovery, and regenerative medicine (reviewed in 1,2).
To expedite the identification and characterization of novel regulators of ES cell maintenance and self-renewal, we developed a fluorescence reporter-based assay to quantitatively measure the self-renewal status in mouse ES cells using the Oct4GiP cells 3. The Oct4GiP cells express the green fluorescent protein (GFP) under the control of the Oct4 gene promoter region 4,5. Oct4 is required for ES cell self-renewal, and is highly expressed in ES cells and quickly down-regulated during differentiation 6,7. As a result, GFP expression and fluorescence in the reporter cells correlates faithfully with the ES cell identity 5, and fluorescence-activated cell sorting (FACS) analysis can be used to closely monitor the self-renewal status of the cells at the single cell level 3,8.
Coupled with RNAi, the Oct4GiP reporter assay can be used to quickly identify and study regulators of ES cell maintenance and self-renewal 3,8. Compared to other methods for assaying self-renewal, it is more convenient, sensitive, quantitative, and of lower cost. It can be carried out in 96- or 384-well plates for large-scale studies such as high-throughput screens or genetic epistasis analysis. Finally, by using other lineage-specific reporter ES cell lines, the assay we describe here can also be modified to study fate specification during ES cell differentiation.

We describe a fluorescence reporter assay to quickly identify and characterize genes that regulate mouse embryonic stem cell maintenance and self-renewal.

Oct4GiP Reporter Assay auf Gene, die Maus embryonalen Stammzellen Wartungs-und Self-Study Erneuerung Regulate

Pluripotency and self-renewal are two defining characteristics of embryonic stem cells (ES cells). Understanding the underlying molecular mechanism will ...

The Use of Chemostats in Microbial Systems Biology

Cells regulate their rate of growth in response to signals from the external world. As the cell grows, diverse cellular processes must be coordinated including macromolecular synthesis, metabolism and ultimately, commitment to the cell division cycle. The chemostat, a method of experimentally controlling cell growth rate, provides a powerful means of systematically studying how growth rate impacts cellular processes - including gene expression and metabolism - and the regulatory networks that control the rate of cell growth. When maintained for hundreds of generations chemostats can be used to study adaptive evolution of microbes in environmental conditions that limit cell growth. We describe the principle of chemostat cultures, demonstrate their operation and provide examples of their various applications. Following a period of disuse after their introduction in the middle of the twentieth century, the convergence of genome-scale methodologies with a renewed interest in the regulation of cell growth and the molecular basis of adaptive evolution is stimulating a renaissance in the use of chemostats in biological research.

Cell growth rate is a regulated process and a primary determinant of cell physiology. Continuous culturing using chemostats enables extrinsic control of cell growth rate by nutrient limitation facilitating the study of molecular networks that control cell growth and how those networks evolve to optimize cell growth.

Der Einsatz von Chemostate in Microbial Systems Biology

Cells regulate their rate of growth in response to signals from the external world. As the cell grows, diverse cellular processes must be coordinated ...

Identification of Key Factors Regulating Self-renewal and Differentiation in EML Hematopoietic Precursor Cells by RNA-sequencing Analysis

Hematopoietic stem cells (HSCs) are used clinically for transplantation treatment to rebuild a patient&#39;s hematopoietic system in many diseases such as leukemia and lymphoma. Elucidating the mechanisms controlling HSCs self-renewal and differentiation is important for application of HSCs for research and clinical uses. However, it is not possible to obtain large quantity of HSCs due to their inability to proliferate in vitro. To overcome this hurdle, we used a mouse bone marrow derived cell line, the EML (Erythroid, Myeloid, and Lymphocytic) cell line, as a model system for this study.
RNA-sequencing (RNA-Seq) has been increasingly used to replace microarray for gene expression studies. We report here a detailed method of using RNA-Seq technology to investigate the potential key factors in regulation of EML cell self-renewal and differentiation. The protocol provided in this paper is divided into three parts. The first part explains how to culture EML cells and separate Lin-CD34+ and Lin-CD34- cells. The second part of the protocol offers detailed procedures for total RNA preparation and the subsequent library construction for high-throughput sequencing. The last part describes the method for RNA-Seq data analysis and explains how to use the data to identify differentially expressed transcription factors between Lin-CD34+ and Lin-CD34- cells. The most significantly differentially expressed transcription factors were identified to be the potential key regulators controlling EML cell self-renewal and differentiation. In the discussion section of this paper, we highlight the key steps for successful performance of this experiment.
In summary, this paper offers a method of using RNA-Seq technology to identify potential regulators of self-renewal and differentiation in EML cells. The key factors identified are subjected to downstream functional analysis in vitro and in vivo.

RNA-sequencing and bioinformatics analyses were used to identify significantly and differentially expressed transcription factors in Lin-CD34+ and Lin-CD34- subpopulations of mouse EMLcells. These transcription factors might play important roles in determining the switch between self-renewing Lin-CD34+ and partially differentiated Lin-CD34- cells.

Identifizierung von Schlüsselfaktoren Regelselbsterneuerung und Differenzierung in EML hämatopoetischen Vorläuferzellen durch RNA-Sequenzierungsanalyse

Hematopoietic stem cells (HSCs) are used clinically for transplantation treatment to rebuild a patient&#39;s hematopoietic system in many diseases such as ...

Use of Enzymatic Biosensors to Quantify Endogenous ATP or H2O2 in the Kidney

Enzymatic microelectrode biosensors have been widely used to measure extracellular signaling in real-time. Most of their use has been limited to brain slices and neuronal cell cultures. Recently, this technology has been applied to the whole organs. Advances in sensor design have made &#160;possible the measuring of&#160;cell signaling in blood-perfused in vivo kidneys. The present protocols list the steps needed to measure ATP and H2O2 signaling in the rat kidney interstitium. Two separate sensor designs are used for the ex vivo and in vivo protocols. Both types of sensor&#160;are coated with&#160;a thin enzymatic biolayer on top of a permselectivity layer to give fast responding, sensitive and selective biosensors. The permselectivity layer protects the signal from the interferents in biological tissue, and the enzymatic layer utilizes&#160;the sequential catalytic reaction of glycerol kinase and glycerol-3-phosphate oxidase in the presence of ATP to produce H2O2. The set of sensors used for the ex vivo studies further detected analyte by oxidation of H2O2 on a platinum/iridium (Pt-Ir) wire electrode. The sensors for the&#160;in vivo studies are instead based on the reduction of H2O2 on a mediator coated gold electrode designed for blood-perfused tissue. Final concentration changes&#160;are detected by real-time amperometry followed by calibration to known concentrations of analyte. Additionally, the specificity of the amperometric signal can be confirmed by the addition of enzymes such as catalase and apyrase that break down H2O2 and ATP correspondingly. These sensors also rely heavily on accurate calibrations before and after each experiment. The following two protocols establish the study of real-time detection of ATP and H2O2 in kidney tissues, and can be further modified to extend the described method for use in other biological preparations or whole organs.

Use of Enzymatic Biosensors to Quantify Endogenous ATP or H2O2 in the Kidney

Enzymatic microelectrode biosensors enable real-time measurements of extracellular cell signaling in biologically-relevant concentrations. The following protocols extend the applications of biosensors to the ex vivo and in vivo detection of ATP and H2O2 in the kidney.

Verwendung enzymatischer Biosensoren auf endogenes ATP oder H Quantifizieren<sub&gt; 2</sub&gt; O<sub&gt; 2</sub&gt; In der Niere

Enzymatic microelectrode biosensors have been widely used to measure extracellular signaling in real-time. Most of their use has been limited to brain ...

Use of the Ramsay Assay to Measure Fluid Secretion and Ion Flux Rates in the Drosophila melanogaster Malpighian Tubule

Modulation of renal epithelial ion transport allows organisms to maintain ionic and osmotic homeostasis in the face of varying external conditions. The Drosophila&#160;melanogaster Malpighian (renal) tubule offers an unparalleled opportunity to study the molecular mechanisms of epithelial ion transport, due to the powerful genetics of this organism and the accessibility of its renal tubules to physiological study. Here, we describe the use of the Ramsay assay to measure fluid secretion rates from isolated fly renal tubules, with the use of ion-specific electrodes to measure sodium and potassium concentrations in the secreted fluid. This assay allows study of transepithelial fluid and ion fluxes of ~20 tubules at a time, without the need to transfer the secreted fluid to a separate apparatus to measure ion concentrations. Genetically distinct tubules can be analyzed to assess the role of specific genes in transport processes. Additionally, the bathing saline can be modified to examine the effects of its chemical characteristics, or drugs or hormones added. In summary, this technique allows the molecular characterization of basic mechanisms of epithelial ion transport in the Drosophila tubule, as well as regulation of these transport mechanisms.

Use of the Ramsay Assay to Measure Fluid Secretion and Ion Flux Rates in the Drosophila melanogaster Malpighian Tubule

This protocol describes the use of the Ramsay assay to measure fluid secretion rates from isolated Malpighian (renal) tubules from Drosophila melanogaster. In addition, the use of ion-specific electrodes to measure sodium and potassium concentrations in the secreted fluid, allowing calculation of transepithelial ion flux, is described.

Die Nutzung der Ramsay Assay zu Flüssigkeitssekretion und Ionenfluss Preise in der Maßnahme<em&gt; Drosophila melanogaster</em&gt; Malpighischen Tubulus

Modulation of renal epithelial ion transport allows organisms to maintain ionic and osmotic homeostasis in the face of varying external conditions. The ...

Studying the Supramolecular Organization of Photosynthetic Membranes within Freeze-fractured Leaf Tissues by Cryo-scanning Electron Microscopy

Cryo-scanning electron microscopy (SEM) of freeze-fractured samples allows investigation of biological structures at near native conditions. Here, we describe a technique for studying the supramolecular organization of photosynthetic (thylakoid) membranes within leaf samples. This is achieved by high-pressure freezing of leaf tissues, freeze-fracturing, double-layer coating and finally cryo-SEM imaging. Use of the double-layer coating method allows acquiring high magnification (&#62;100,000X) images with minimal beam damage to the frozen-hydrated samples as well as minimal charging effects. Using the described procedures we investigated the alterations in supramolecular distribution of photosystem and light-harvesting antenna protein complexes that take place during dehydration of the resurrection plant Craterostigma pumilum, in situ.

Here we describe a procedure for studying freeze-fractured plant tissues. High-pressure frozen leaf samples are freeze-fractured and double-layer coated, yielding well preserved frozen-hydrated samples that are imaged using the cryo-scanning electron microscope at high magnifications with minimal beam damage.

Die Untersuchung der supramolekulare Organisation Photosynthetic Membranen innerhalb Gefrier gebrochen Blattgewebe von Cryo-Rasterelektronenmikroskopie

Cryo-scanning electron microscopy (SEM) of freeze-fractured samples allows investigation of biological structures at near native conditions. Here, we ...

Development of an Insert Co-culture System of Two Cellular Types in the Absence of Cell-Cell Contact

The role of secreted soluble factors in the modification of cellular responses is a recurrent theme in the study of all tissues and systems. In an attempt to make straightforward the very complex relationships between the several cellular subtypes that compose multicellular organisms, in vitro techniques have been developed to help researchers acquire a detailed understanding of single cell populations. One of these techniques uses inserts with a permeable membrane allowing secreted soluble factors to diffuse. Thus, a population of cells grown in inserts can be co-cultured in a well or dish containing a different cell type for evaluating cellular changes following paracrine signaling in the absence of cell-cell contact. Such insert co-culture systems offer various advantages over other co-culture techniques, namely bidirectional signaling, conserved cell polarity and population-specific detection of cellular changes. In addition to being utilized in the field of inflammation, cancer, angiogenesis and differentiation, these co-culture systems are of prime importance in the study of the intricate relationships that exist between the different cellular subtypes present in the central nervous system, particularly in the context of neuroinflammation. This article offers general methodological guidelines in order to set up an experiment in order to evaluating cellular changes mediated by secreted soluble factors using an insert co-culture system. Moreover, a specific protocol to measure the neuroinflammatory effects of cytokines secreted by lipopolysaccharide-activated N9 microglia on neuronal PC12 cells will be detailed, offering a concrete understanding of insert co-culture methodology.

In multicellular organisms, secreted soluble factors elicit responses from different cell types as a result of paracrine signaling. Insert co-culture systems offer a simple way to assess the changes mediated by secreted soluble factors in the absence of cell-cell contact.

Entwicklung eines Insert Co-Kultursystem von zwei Cellular Typen in der Abwesenheit von Zell-Zell-Kontakt

The role of secreted soluble factors in the modification of cellular responses is a recurrent theme in the study of all tissues and systems. In an attempt ...

Methods Article

Die Verwendung von SC1 (Pluripotin) zu MESC Self-Erneuerung in der Abwesenheit von LIF-Support