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	<li>Fernyhough, M. E., Helterline, D. L., Vierck, J. L., Hill, R. A., Dodson, M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coulter+counter+use+in+the+enumeration+of+muscle+and+fat+stem+cells.">Coulter counter use in the enumeration of muscle and fat stem cells.</a> Methods. Cell. Sci. 25, 221-225 (2003).</li><li>Blades, A. N., Flavell, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Observations+on+the+use+of+the+Coulter+model+D+electronic+cell+counter+in+clinical+haematology.">Observations on the use of the Coulter model D electronic cell counter in clinical haematology.</a> J. Clin. Pathol. 16, 158-163 (1963).</li><li>Morris, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Particle+Size+Analysis+of+Beer+Solids+using+a+Coulter+Counter.">Particle Size Analysis of Beer Solids using a Coulter Counter.</a> J. Inst. Brew. 90, 162-166 (1984).</li><li>Marth, E. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electronic+Somatic+Cell+Counting+Procedure.">Electronic Somatic Cell Counting Procedure.</a> Standard Methods for the Examination of Dairy Products. , 134-140 (1978).</li><li>Parks, L. R., Jurbergs, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Number+and+size+distribution+of+particles+in+cellulosic+solutions.">Number and size distribution of particles in cellulosic solutions.</a> J. Appl. Polym. Sci. 11, 193-199 (1960).</li><li>Davis, R. E., Green, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automatic+platelet+counting+with+the+Couler+particle+counter.">Automatic platelet counting with the Couler particle counter.</a> J. Clin. Pathol. 20, 777-779 (1967).</li><li>Dittami, G. D., Rabbitt, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrically+evoking+and+electrochemically+resolving+quantal+release+on+a+microchip.">Electrically evoking and electrochemically resolving quantal release on a microchip.</a> Lab on a Chip. 10, 30-35 (2010).</li><li>Nahreini, P., Hanson, A., Prasad, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-yield+production+of+recombinant+antibody+fragments+in+HEK-293+cells+using+sodium+butyrate.">High-yield production of recombinant antibody fragments in HEK-293 cells using sodium butyrate.</a> BioTechiques. 34, 968-972 (2003).</li><li>Escuyer, V., Collier, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anthrax+Protective+Antigen+Interacts+with+a+Specific+Receptor+on+the+surface+of+CHO-K1+Cells.">Anthrax Protective Antigen Interacts with a Specific Receptor on the surface of CHO-K1 Cells.</a> Infection and Immunity. 59, 3381-3386 (1991).</li><li>Isaacs, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Borrelia+bugdorferi+bind+to+epithelial+cell+proteoglycans.">Borrelia bugdorferi bind to epithelial cell proteoglycans.</a> J. Clin. Invest. 93, 809-819 (1994).</li><li>Saito, Y., Takahashi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+selenoprotein+P+as+a+selenium+supply+protein.">Characterization of selenoprotein P as a selenium supply protein.</a> Eur. J. Biochem. 269, 5746-5751 (2002).</li><li>Kataoka, S., Tsuruo, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physician+Education:+Apoptosis.">Physician Education: Apoptosis.</a> Oncologist. 1, 399-401 (1996).</li><li>Liegler, T. J., Hyun, W., Yen, T. S., Stites, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+and+quantification+of+live,+apoptotic,+and+necrotic+human+peripheral+lymphocytes+by+single-laser+flow+cytometry.">Detection and quantification of live, apoptotic, and necrotic human peripheral lymphocytes by single-laser flow cytometry.</a> Clin. Diagn. Lab Immunol. 2, 369-376 (1995).</li><li>Sheridan, J. W., Bishop, C. J., Simmons, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biophysical+and+morphological+correlates+of+kinetic+change+and+death+in+a+starved+human+melanoma+cell+line.">Biophysical and morphological correlates of kinetic change and death in a starved human melanoma cell line.</a> J. Cell. Sci. 49, 119-137 (1981).</li><li>Dittami, G. M., Rabbitt, R. D., Ayliffe, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ORFLO+Moxi+Z:+Revolutionizing+electronic+cell+count+accuracy+and+cell+viability+estimates+through+curve+fitting.">ORFLO Moxi Z: Revolutionizing electronic cell count accuracy and cell viability estimates through curve fitting.</a> Life Science Magazine, VWR International. , (2011).</li></ol>

גרגורי מ Dittami ו HE Ayliffe הם עובדי Orflo טכנולוגיות, החברה נועד, מייצרת ומשווקת צ&#39;Moxi ריצ&#39;רד ד Rabbitt מספק חלקית, התמחות בייעוץ ששולם Orflo טכנולוגיות. הפקה וגישה חופשית למאמר זה ממומן על ידי Orflo טכנולוגיות.

יישום הגישה הבסיסית קולטר יכול להיות דטרמיניסטי מאוד הדיוק הכולל של המדידות. אזור קריטי הוא תיקון של ספירת תאים גלם &quot;אירועים צירוף מקרים&quot; שבהם שני תאים או יותר בו זמנית שעוברים דרך פתח, והם נמדדים כאירוע חשמל אחת. &quot;אירועים צירוף מקרים&quot; לתרום שגיאה אשר משתנה בהתאם למספר גורמים, ביניהם גודל התא ומידת אשכולות (Davis et al 1967) 6. כתוצאה מכך, תיקון במקרה הנדרש למדגם נתון לא ניתן לחזות, משתנה באופן נרחב בין התא / סוגי החלקיקים וגם בין תרבויות שונות של סוגי תאים זהים. הוקמה התיאוריה, נעוצה בפרסומים הראשונים של קולטר, כולל החלת התאמה לוגריתמי של ספירת גלם המבוססים על מספר האירועים שנצפו ו אמפירי שנקבע, חלקיק מסוים גורם התיקון, z. בעוד ספירת מדויקים ניתן להשיג כראוי עם לאאלגוריתם תיקון שלו, זה מוגבל תחולת המעשי בשל שוני גדול בין מספר ערכים זי בין סוגי תאים ועל הקושי המקביל לנבא בדייקנות את הערך שלו. כאן, באמצעות ספירת &quot;נכון&quot; תא מזוהה על ידי מתאים Moxi עקומת Z יחד עם אלגוריתם תיקון צירוף מקרים, Z Moxi דינמי מתקנת עבור מקרה כדי להשיג את הריכוזים האמיתיים. בהשוואה לתוצאות שהושגו באמצעות high-end קולטר Z2, המיוצר Z Moxi סעיפים דומים על פני טווח הריכוז של 0 - 500,000 תאים למ&quot;ל (קלטת סוג M) ו 3000 - 2-2.5e 6 תאים למ&quot;ל (קלטת S Type) . יתר על כן, Z Moxi משיגה דיוק ספירת עם מקדם נמוך דומה של שונות בספירת ו דיוק לשינוי גודל החלקיקים האופייני תקן זהב, קולטר, טכניקה ספירת תאים. יתר על כן, הנתונים שהוצגו כאן מצביעים על כך Z Moxi יכול לספק מידע רב ערךלגבי הבריאות הכללית של תרביות תאים. Z Moxi ממנף את הגישה העקומה הולמת עם אלגוריתם תוכנה קניינית כדי לקבוע הערכה בריאות ותרבות. שינויים מורפולוגיים הקשורות מוות של תאים, כגון blebbing, מתפרקת, ועיוותים נפחי (Kataoka ו Tsuruo 1996, Liegler et al 1995, Sheridan et al 1981) 12-14, מאפשרים Moxi-Z כדי להבחין בהבדלים בין impedimetric חיים אוכלוסיות תאים מתים / פסולת האוכלוסיות. MVI מופק על ידי ניתוח התפלגות תרבות / החלקיקים בגודל לזהות את התרומה היחסית של פסולת החלקיקים, תאים נמקי מכווץ, ואת עקומת-מצויד האוכלוסייה התא של עניין. ערך MVI ובכך משקף המדד האוכלוסייה או מידה ratiometric של ספירת אוכלוסין monodisperse ביחס לפרופיל החלקיקים הכולל האוכלוסייה. ערך זה הוא אז אלגוריתמית עונתיות נתוני האוכלוסייה המבוססים על תצפיות אמפיריות. Becausדואר MVI מסתכל פרמטרים אחרים מאשר גישות צביעה מסורתיות, זה לא צפוי לשקף את הטכניקות הללו אלא מספק תצוגה חלופית חשובה לבריאותם של התרבות תאים, במיוחד ביחס פסולת ומזהמים חיידקים. לסיכום, נגד Moxi-Z התא היא מכשיר אולטרה benchtop קטן המספק מדויקים, מבחני לשחזור של ספירת תאים, גודל התא, בריאות התא באמצעות העיקרון קולטר עקומת-הולם האלגוריתמים בשילוב עם טכנולוגיית סרט דק פטנט חיישן . עם קלטת M סוג הוא מסוגל לספור חלקיקים הנעים בין 4 - 25 מיקרון בקוטר (טווח דינמי של 2 - 34 מיקרון), ב -8 שניות. עם קלטת S Type היא מסוגלת לספור חלקיקים הנעים בין 3 - 20 מיקרון בקוטר (טווח דינמי של 2 - 26 מיקרון), תוך 15 שניות. יתר על כן, Moxi-Z מבצעת הערכות בריאות ללא שימוש של חומרים כימיים. זה Inte העבודה הרבה פחותnsive וסובייקטיבי יותר לספור ידנית. לעומת ספירת קולטר רגיל, Moxi הוא מהיר יותר, משמעותית יותר, מספק מידע נוסף, דורש תחזוקה הרבה פחות, קל יותר לשימוש, ומהווה חלק קטן מהעלות.

<table border="1" style=";text-align:right;direction:rtl"><tbody><tr><td> שם מגיב </td><td> חברה </td><td> מספר קטלוגי </td><td> תגובות </td></tr><tr><td> ORFLO diluent </td><td> ORFLO </td><td> MXA006 </td><td></td></tr><tr><td> קלטת Dispenser </td><td> ORFLO </td><td></td><td> חנויות עד 25 קלטות של מחלק נוח </td></tr><tr><td> כבל USB </td><td> ORFLO </td><td></td><td> המכשיר מתחבר למחשב / Mac או מתאם מתח </td></tr><tr><td> מתאם מתח (ארה&quot;ב והאיחוד האירופי דגמים בלבד) </td><td> ORFLO </td><td></td><td> מתחבר כבל ה-USB לשקע ה-AC </td></tr><tr><td> USB Flash Drive </td><td> ORFLO </td><td></td><td> חנויות Moxאני Z תוכנה הוראות שימוש </td></tr><tr><td> בדוק כיול חרוזים </td><td> ORFLO </td><td></td><td></td></tr><tr><td> כיול אלקטרוני קלטת </td><td> ORFLO </td><td></td><td> קלטת אלקטרונית לאימות פעולת המערכת כיול נכונה </td></tr></tbody></table>

determination of mammalian cell counts, cell size and cell health using the moxi z mini automated cell counter

Particle and cell counting is used for a variety of applications including routine cell culture, hematological analysis, and industrial controls1-5. A critical breakthrough in cell/particle counting technologies was the development of the Coulter technique by Wallace Coulter over 50 years ago. The technique involves the application of an electric field across a micron-sized aperture and hydrodynamically focusing single particles through the aperture. The resulting occlusion of the aperture by the particles yields a measurable change in electric impedance that can be directly and precisely correlated to cell size/volume. The recognition of the approach as the benchmark in cell/particle counting stems from the extraordinary precision and accuracy of its particle sizing and counts, particularly as compared to manual and imaging based technologies (accuracies on the order of 98% for Coulter counters versus 75-80% for manual and vision-based systems). This can be attributed to the fact that, unlike imaging-based approaches to cell counting, the Coulter Technique makes a true three-dimensional (3-D) measurement of cells/particles which dramatically reduces count interference from debris and clustering by calculating precise volumetric information about the cells/particles. Overall this provides a means for enumerating and sizing cells in a more accurate, less tedious, less time-consuming, and less subjective means than other counting techniques6.
Despite the prominence of the Coulter technique in cell counting, its widespread use in routine biological studies has been prohibitive due to the cost and size of traditional instruments. Although a less expensive Coulter-based instrument has been produced, it has limitations as compared to its more expensive counterparts in the correction for "coincidence events" in which two or more cells pass through the aperture and are measured simultaneously. Another limitation with existing Coulter technologies is the lack of metrics on the overall health of cell samples. Consequently, additional techniques must often be used in conjunction with Coulter counting to assess cell viability. This extends experimental setup time and cost since the traditional methods of viability assessment require cell staining and/or use of expensive and cumbersome equipment such as a flow cytometer.
The Moxi Z mini automated cell counter, described here, is an ultra-small benchtop instrument that combines the accuracy of the Coulter Principle with a thin-film sensor technology to enable precise sizing and counting of particles ranging from 3-25 microns, depending on the cell counting cassette used. The M type cassette can be used to count particles from with average diameters of 4 - 25 microns (dynamic range 2 - 34 microns), and the Type S cassette can be used to count particles with and average diameter of 3 - 20 microns (dynamic range 2 - 26 microns). Since the system uses a volumetric measurement method, the 4-25 microns corresponds to a cell volume range of 34 - 8,180 fL and the 3 - 20 microns corresponds to a cell volume range of 14 - 4200 fL, which is relevant when non-spherical particles are being measured. To perform mammalian cell counts using the Moxi Z, the cells to be counted are first diluted with ORFLO or similar diluent. A cell counting cassette is inserted into the instrument, and the sample is loaded into the port of the cassette. Thousands of cells are pulled, single-file through a "Cell Sensing Zone" (CSZ) in the thin-film membrane over 8-15 seconds. Following the run, the instrument uses proprietary curve-fitting in conjunction with a proprietary software algorithm to provide coincidence event correction along with an assessment of overall culture health by determining the ratio of the number of cells in the population of interest to the total number of particles. The total particle counts include shrunken and broken down dead cells, as well as other debris and contaminants. The results are presented in histogram format with an automatic curve fit, with gates that can be adjusted manually as needed.
Ultimately, the Moxi Z enables counting with a precision and accuracy comparable to a Coulter Z2, the current gold standard, while providing additional culture health information. Furthermore it achieves these results in less time, with a smaller footprint, with significantly easier operation and maintenance, and at a fraction of the cost of comparable technologies.

Watch this Scientific Journal Video about Determination of Mammalian Cell Counts, Cell Size and Cell Health Using the Moxi Z Mini Automated Cell Counter at JoVE.com

Determination of Mammalian Cell Counts, Cell Size and Cell Health Using the Moxi Z Mini Automated Cell Counter

Z Moxi נגד מיניאטורי תא אוטומטי הוא כלי רומן המשלב עקרון קולטר עם הטכנולוגיה סרט דק פטנט חיישן אלגוריתם תוכנה קניינית לבצע שינוי גודל ועוד היד נטויה של מגוון רחב של גודל החלקיקים, כמו גם כדי לקבוע את הבריאות הכללית של monodisperse תא תרבויות יונקים. פרוטוקול זה מתאר את השימוש בכלי זה לספור ולהעריך את הבריאות של תרביות תאים.

קביעת ספירת תאים יונקים, גודל התא ובריאות נייד באמצעות ת Moxi מיני מונה אוטומטי Cell

Particle and cell counting is used for a variety of applications including routine cell culture, hematological analysis, and industrial controls1-5. A ...

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Biology

24.5K Views.  Orflo Technologies. Z Moxi נגד מיניאטורי תא אוטומטי הוא כלי רומן המשלב עקרון קולטר עם הטכנולוגיה סרט דק פטנט חיישן אלגוריתם תוכנה קניינית לבצע שינוי גודל ועוד היד נטויה של מגוון רחב של גודל החלקיקים, כמו גם כדי לקבוע את הבריאות הכללית של monodisperse תא תרבויות יונקים. פרוטוקול זה מתאר את הש...

Video: Determination of Mammalian Cell Counts, Cell Size and Cell Health Using the Moxi Z Mini Automated Cell Counter

Long-term Imaging Mammalian Cells using Wide-Field Microscopy

לטווח ארוך הדמיה בתאי יונקים באמצעות מיקרוסקופית שדה רחב

Pulse-chase Analysis of N-linked Sugar Chains from Glycoproteins in Mammalian Cells

Attachment of the Glc3Man9GlcNAc2 precursor oligosaccharide to nascent polypeptides in the ER is a common modification for secretory proteins. Although this modification was implicated in several biological processes, additional aspects of its function are emerging, with recent evidence of its role in the production of signals for glycoprotein quality control and trafficking. Thus, phenomena related to N-linked glycans and their processing are being intensively investigated. Methods that have been recently developed for proteomic analysis have greatly improved the characterization of glycoprotein N-linked glycans. Nevertheless, they do not provide insight into the dynamics of the sugar chain processing involved. For this, labeling and pulse-chase analysis protocols are used that are usually complex and give very low yields. We describe here a simple method for the isolation and analysis of metabolically labeled N-linked oligosaccharides. The protocol is based on labeling of cells with [2-3H] mannose, denaturing lysis and enzymatic release of the oligosaccharides from either a specifically immunoprecipitated protein of interest or from the general glycoprotein pool by sequential treatments with endo H and N-glycosidase F, followed by molecular filtration (Amicon). In this method the isolated oligosaccharides serve as an input for HPLC analysis, which allows discrimination between various glycan structures according to the number of monosaccharide units comprising them, with a resolution of a single monosaccharide. Using this method we were able to study high mannose N-linked oligosaccharide profiles of total cell glycoproteins after pulse-chase in normal conditions and under proteasome inhibition. These profiles were compared to those obtained from an immunoprecipitated ER-associated degradation (ERAD) substrate. Our results suggest that most NIH 3T3 cellular glycoproteins are relatively stable and that most of their oligosaccharides are trimmed to Man9-8GlcNAc2. In contrast, unstable ERAD substrates are trimmed to Man6-5GlcNAc2 and glycoproteins bearing these species accumulate upon inhibition of proteasomal degradation.

We describe a method for analysis of the alteration of N-linked glycans through the early life of glycoproteins after their biosynthesis in mammalian cells. This is achieved by pulse-chase analysis of metabolically labeled glycans, enzymatic release from glycoproteins and examination by HPLC.

Pulse-מרדף ניתוח של N-linked שרשראות סוכר מ גליקופרוטאינים בתאי יונקים

Attachment of the Glc3Man9GlcNAc2 precursor oligosaccharide to nascent polypeptides in the ER is a common modification for secretory proteins. Although ...

Using an Automated Cell Counter to Simplify Gene Expression Studies: siRNA Knockdown of IL-4 Dependent Gene Expression in Namalwa Cells

The use of siRNA mediated gene knockdown is continuing to be an important tool in studies of gene expression.  siRNA studies are being conducted not only to study the effects of downregulating single genes, but also to interrogate signaling pathways and other complex interaction networks.  These pathway analyses require both the use of relevant cellular models and methods that cause less perturbation to the cellular physiology.  Electroporation is increasingly being used as an effective way to introduce siRNA and other nucleic acids into difficult to transfect cell lines and primary cells without altering the signaling pathway under investigation. There are multiple critical steps to a successful siRNA experiment, and there are ways to simplify the work while improving the data quality at several experimental stages.  To help you get started with your siRNA mediated gene knockdown project, we will demonstrate how to perform a pathway study complete from collecting and counting the cells prior to electroporation through post transfection real-time PCR gene expression analysis.  The following study investigates the role of the transcriptional activator STAT6 in IL-4 dependent gene expression of CCL17 in a Burkitt lymphoma cell line (Namalwa).  The techniques demonstrated are useful for a wide range of siRNA-based experiments on both adherent and suspension cells.  We will also show how to streamline cell counting with the TC10 automated cell counter, how to electroporate multiple samples simultaneously using the MXcell electroporation system, and how to simultaneously assess RNA quality and quantity with the Experion automated electrophoresis system.

This procedure describes a quick and easy workflow to introduce siRNA into difficult to transfect cell lines and follow gene expression by real-time PCR. Use of an automated cell counter, multi-well electroporation plate, and automated electrophoresis station provide quick and reliable results without the need for expensive robotic handling.

שימוש מונה תא אוטומטי כדי לפשט את הביטוי מחקרים ג&#39;ין: siRNA מציאה הביטוי IL 4-Gene תלויים תאים Namalwa

The use of siRNA mediated gene knockdown is continuing to be an important tool in studies of gene expression.  siRNA studies are being conducted not only ...

MISSION esiRNA for RNAi Screening in Mammalian Cells

RNA interference (RNAi) is a basic cellular mechanism for the control of gene expression. RNAi is induced by short double-stranded RNAs also known as small interfering RNAs (siRNAs). The short double-stranded RNAs originate from longer double stranded precursors by the activity of Dicer, a protein of the RNase III family of endonucleases. The resulting fragments are components of the RNA-induced silencing complex (RISC), directing it to the cognate target mRNA. RISC cleaves the target mRNA thereby reducing the expression of the encoded protein1,2,3. RNAi has become a powerful and widely used experimental method for loss of gene function studies in mammalian cells utilizing small interfering RNAs.
Currently two main methods are available for the production of small interfering RNAs. One method involves chemical synthesis, whereas an alternative method employs endonucleolytic cleavage of target specific long double-stranded RNAs by RNase III in vitro. Thereby, a diverse pool of siRNA-like oligonucleotides is produced which is also known as endoribonuclease-prepared siRNA or esiRNA. A comparison of efficacy of chemically derived siRNAs and esiRNAs shows that both triggers are potent in target-gene silencing. Differences can, however, be seen when comparing specificity. Many single chemically synthesized siRNAs produce prominent off-target effects, whereas the complex mixture inherent in esiRNAs leads to a more specific knockdown10.
In this study, we present the design of genome-scale MISSION esiRNA libraries and its utilization for RNAi screening exemplified by a DNA-content screen for the identification of genes involved in cell cycle progression. We show how to optimize the transfection protocol and the assay for screening in high throughput. We also demonstrate how large data-sets can be evaluated statistically and present methods to validate primary hits. Finally, we give potential starting points for further functional characterizations of validated hits.

Here we use a human esiRNA library in a high-throughput screen for genes involved in cell division. We demonstrate how to set up and conduct an esiRNA screens, as well as how to analyze and validate the results.

המשימה esiRNA עבור הקרנת RNAi בתאי יונקים

RNA interference (RNAi) is a basic cellular mechanism for the control of gene expression. RNAi is induced by short double-stranded RNAs also known as ...

Determining Cell Number During Cell Culture using the Scepter Cell Counter

Counting cells is often a necessary but tedious step for in vitro cell culture. Consistent cell concentrations ensure experimental reproducibility and accuracy. Cell counts are important for monitoring cell health and proliferation rate, assessing immortalization or transformation, seeding cells for subsequent experiments, transfection or infection, and preparing for cell-based assays. It is important that cell counts be accurate, consistent, and fast, particularly for quantitative measurements of cellular responses.
Despite this need for speed and accuracy in cell counting, 71% of 400 researchers surveyed1 who count cells using a hemocytometer. While hemocytometry is inexpensive, it is laborious and subject to user bias and misuse, which results in inaccurate counts. Hemocytometers are made of special optical glass on which cell suspensions are loaded in specified volumes and counted under a microscope. Sources of errors in hemocytometry include: uneven cell distribution in the sample, too many or too few cells in the sample, subjective decisions as to whether a given cell falls within the defined counting area, contamination of the hemocytometer, user-to-user variation, and variation of hemocytometer filling rate2.
To alleviate the tedium associated with manual counting, 29% of researchers count cells using automated cell counting devices; these include vision-based counters, systems that detect cells using the Coulter principle, or flow cytometry1. For most researchers, the main barrier to using an automated system is the price associated with these large benchtop instruments1.
The Scepter cell counter is an automated handheld device that offers the automation and accuracy of Coulter counting at a relatively low cost. The system employs the Coulter principle of impedance-based particle detection3 in a miniaturized format using a combination of analog and digital hardware for sensing, signal processing, data storage, and graphical display. The disposable tip is engineered with a microfabricated, cell- sensing zone that enables discrimination by cell size and cell volume at sub-micron and sub-picoliter resolution. Enhanced with precision liquid-handling channels and electronics, the Scepter cell counter reports cell population statistics graphically displayed as a histogram.

The Scepter Cell Counter is a handheld automated device that can be used to count cells, monitor cell diameter and volume, and be used to check the health and quality of cellular populations from one culture to the next.

קביעת מספר נייד במהלך תרבית תאים באמצעות מונה Cell שרביט השלטון

Counting cells is often a necessary but tedious step for in vitro cell culture. Consistent cell concentrations ensure experimental reproducibility and ...

Analysis of Cell Cycle Position in Mammalian Cells

The regulation of cell proliferation is central to tissue morphogenesis during the development of multicellular organisms. Furthermore, loss of control of cell proliferation underlies the pathology of diseases like cancer. As such there is great need to be able to investigate cell proliferation and quantitate the proportion of cells in each phase of the cell cycle. It is also of vital importance to indistinguishably identify cells that are replicating their DNA within a larger population. Since a cell&prime;s decision to proliferate is made in the G1 phase immediately before initiating DNA synthesis and progressing through the rest of the cell cycle, detection of DNA synthesis at this stage allows for an unambiguous determination of the status of growth regulation in cell culture experiments.
DNA content in cells can be readily quantitated by flow cytometry of cells stained with propidium iodide, a fluorescent DNA intercalating dye. Similarly, active DNA synthesis can be quantitated by culturing cells in the presence of radioactive thymidine, harvesting the cells, and measuring the incorporation of radioactivity into an acid insoluble fraction. We have considerable expertise with cell cycle analysis and recommend a different approach. We Investigate cell proliferation using bromodeoxyuridine/fluorodeoxyuridine (abbreviated simply as BrdU) staining that detects the incorporation of these thymine analogs into recently synthesized DNA. Labeling and staining cells with BrdU, combined with total DNA staining by propidium iodide and analysis by flow cytometry1 offers the most accurate measure of cells in the various stages of the cell cycle. It is our preferred method because it combines the detection of active DNA synthesis, through antibody based staining of BrdU, with total DNA content from propidium iodide. This allows for the clear separation of cells in G1 from early S phase, or late S phase from G2/M. Furthermore, this approach can be utilized to investigate the effects of many different cell stimuli and pharmacologic agents on the regulation of progression through these different cell cycle phases.
In this report we describe methods for labeling and staining cultured cells, as well as their analysis by flow cytometry. We also include experimental examples of how this method can be used to measure the effects of growth inhibiting signals from cytokines such as TGF-&beta;1, and proliferative inhibitors such as the cyclin dependent kinase inhibitor, p27KIP1. We also include an alternate protocol that allows for the analysis of cell cycle position in a sub-population of cells within a larger culture5. In this case, we demonstrate how to detect a cell cycle arrest in cells transfected with the retinoblastoma gene even when greatly outnumbered by untransfected cells in the same culture. These examples illustrate the many ways that DNA staining and flow cytometry can be utilized and adapted to investigate fundamental questions of mammalian cell cycle control.

Determining the cell cycle position of a population of cells, or understanding how signals affect proliferation, can be readily measured by flow cytometry using this protocol. We report a simple experimental approach to staining cells and quantifying their position in the cell cycle.

ניתוח של עמדת מחזור התא בתאי יונקים

The regulation of cell proliferation is central to tissue morphogenesis during the development of multicellular organisms. Furthermore, loss of control of ...

Pull-down of Calmodulin-binding Proteins

Calcium (Ca2+) is an ion vital in regulating cellular function through a variety of mechanisms. Much of Ca2+ signaling is mediated through the calcium-binding protein known as calmodulin (CaM)1,2. CaM is involved at multiple levels in almost all cellular processes, including apoptosis, metabolism, smooth muscle contraction, synaptic plasticity, nerve growth, inflammation and the immune response. A number of proteins help regulate these pathways through their interaction with CaM. Many of these interactions depend on the conformation of CaM, which is distinctly different when bound to Ca2+ (Ca2+-CaM) as opposed to its Ca2+-free state (ApoCaM)3.
While most target proteins bind Ca2+-CaM, certain proteins only bind to ApoCaM. Some bind CaM through their IQ-domain, including neuromodulin4, neurogranin (Ng)5, and certain myosins6. These proteins have been shown to play important roles in presynaptic function7, postsynaptic function8, and muscle contraction9, respectively. Their ability to bind and release CaM in the absence or presence of Ca2+ is pivotal in their function. In contrast, many proteins only bind Ca2+-CaM and require this binding for their activation. Examples include myosin light chain kinase10, Ca2+/CaM-dependent kinases (CaMKs)11 and phosphatases (e.g. calcineurin)12, and spectrin kinase13, which have a variety of direct and downstream effects14.
The effects of these proteins on cellular function are often dependent on their ability to bind to CaM in a Ca2+-dependent manner. For example, we tested the relevance of Ng-CaM binding in synaptic function and how different mutations affect this binding. We generated a GFP-tagged Ng construct with specific mutations in the IQ-domain that would change the ability of Ng to bind CaM in a Ca2+-dependent manner. The study of these different mutations gave us great insight into important processes involved in synaptic function8,15. However, in such studies, it is essential to demonstrate that the mutated proteins have the expected altered binding to CaM.
Here, we present a method for testing the ability of proteins to bind to CaM in the presence or absence of Ca2+, using CaMKII and Ng as examples. This method is a form of affinity chromatography referred to as a CaM pull-down assay. It uses CaM-Sepharose beads to test proteins that bind to CaM and the influence of Ca2+ on this binding. It is considerably more time efficient and requires less protein relative to column chromatography and other assays. Altogether, this provides a valuable tool to explore Ca2+/CaM signaling and proteins that interact with CaM.

Calmodulin (CaM) pull-down assay is an effective way to investigate the interaction of CaM with various proteins. This method uses CaM-sepharose beads for efficient and specific analysis of CaM-binding proteins. This provides an important tool to explore CaM signaling in cellular function.

הנפתח של calmodulin מחייב חלבונים

Calcium (Ca2+) is an ion vital in regulating cellular function through a variety of mechanisms. Much of Ca2+ signaling is mediated through the ...

Measurement of Heme Synthesis Levels in Mammalian Cells

Heme serves as the prosthetic group for a wide variety of proteins known as hemoproteins, such as hemoglobin, myoglobin and cytochromes. It is involved in various molecular and cellular processes such as gene transcription, translation, cell differentiation and cell proliferation. The biosynthesis levels of heme vary across different tissues and cell types and is altered in diseased conditions such as anemia, neuropathy and cancer. This technique uses [4-14C] 5-aminolevulinic acid ([14C] 5-ALA), one of the early precursors in the heme biosynthesis pathway to measure the levels of heme synthesis in mammalian cells. This assay involves incubation of cells with [14C] 5-ALA followed by extraction of heme and measurement of the radioactivity incorporated into heme. This procedure is accurate and quick. This method measures the relative levels of heme biosynthesis rather than the total heme content. To demonstrate the use of this technique the levels of heme biosynthesis were measured in several mammalian cell lines.

Altered intracellular heme levels are associated with common diseases such as cancer. Thus, there is a need to measure heme biosynthesis levels in diverse cells. The goal of this protocol is to provide a fast and sensitive method to measure and compare the levels of heme synthesis in different cells.

מדידה של רמות הרן סינתזה בתאי יונקים

Heme serves as the prosthetic group for a wide variety of proteins known as hemoproteins, such as hemoglobin, myoglobin and cytochromes. It is involved in ...

Generation of Plasmid Vectors Expressing FLAG-tagged Proteins Under the Regulation of Human Elongation Factor-1&#945; Promoter Using Gibson Assembly

Gibson assembly (GA) cloning offers a rapid, reliable, and flexible alternative to conventional DNA cloning methods. We used GA to create customized plasmids for expression of exogenous genes in mouse embryonic stem cells (mESCs). Expression of exogenous genes under the control of the SV40 or human cytomegalovirus promoters diminishes quickly after transfection into mESCs. A remedy for this diminished expression is to use the human elongation factor-1 alpha (hEF1&#945;) promoter to drive gene expression. Plasmid vectors containing hEF1&#945; are not as widely available as SV40- or CMV-containing plasmids, especially those also containing N-terminal 3xFLAG-tags. The protocol described here is a rapid method to create plasmids expressing FLAG-tagged CstF-64 and CstF-64 mutant under the expressional regulation of the hEF1&#945; promoter. GA uses a blend of DNA exonuclease, DNA polymerase and DNA ligase to make cloning of overlapping ends of DNA fragments possible. Based on the template DNAs we had available, we designed our constructs to be assembled into a single sequence. Our design used four DNA fragments: pcDNA 3.1 vector backbone, hEF1&#945; promoter part 1, hEF1&#945; promoter part 2 (which contained 3xFLAG-tag purchased as a double-stranded synthetic DNA fragment), and either CstF-64 or specific CstF-64 mutant. The sequences of these fragments were uploaded to a primer generation tool to design appropriate PCR primers for generating the DNA fragments. After PCR, DNA fragments were mixed with the vector containing the selective marker and the GA cloning reaction was assembled. Plasmids from individual transformed bacterial colonies were isolated. Initial screen of the plasmids was done by restriction digestion, followed by sequencing. In conclusion, GA allowed us to create customized plasmids for gene expression in 5 days, including construct screens and verification.

Generation of Plasmid Vectors Expressing FLAG-tagged Proteins Under the Regulation of Human Elongation Factor-1&amp;#945; Promoter Using Gibson Assembly

Synthesis of custom plasmids is labor and time consuming. This protocol describes the use of Gibson assembly cloning to reduce the work and duration of custom DNA cloning procedure. The protocol described also produces reliable tagged protein constructs for mammalian expression at similar cost to the traditional cut-and-paste DNA cloning.

דור של פלסמיד וקטורים לבטא חלבונים מתויג FLAG על פי תקנות ההסדרה של יזם אדם התארכות Factor-1α שימוש גיבסון עצרת

Gibson assembly (GA) cloning offers a rapid, reliable, and flexible alternative to conventional DNA cloning methods. We used GA to create customized ...

Direct Protein Delivery to Mammalian Cells Using Cell-permeable Cys2-His2 Zinc-finger Domains

Due to their modularity and ability to be reprogrammed to recognize a wide range of DNA sequences, Cys2-His2 zinc-finger DNA-binding domains have emerged as useful tools for targeted genome engineering. Like many other DNA-binding proteins, zinc-fingers also possess the innate ability to cross cell membranes. We recently demonstrated that this intrinsic cell-permeability could be leveraged for intracellular protein delivery. Genetic fusion of zinc-finger motifs leads to efficient transport of protein and enzyme cargo into a broad range of mammalian cell types. Unlike other protein transduction technologies, delivery via zinc-finger domains does not inhibit enzyme activity and leads to high levels of cytosolic delivery. Here a detailed step-by-step protocol is presented for the implementation of zinc-finger technology for protein delivery into mammalian cells. Key steps for achieving high levels of intracellular zinc-finger-mediated delivery are highlighted and strategies for maximizing the performance of this system are discussed.

Direct Protein Delivery to Mammalian Cells Using Cell-permeable Cys2-His2 Zinc-finger Domains

Zinc-finger domains are intrinsically cell-permeable and capable of mediating protein delivery into a broad range of mammalian cell types. Here, a detailed step-by-step protocol for implementing zinc-finger technology for intracellular protein delivery is presented.

משלוח חלבון ישיר לשימוש בתאי יונקי Cys Cell-חדיר<sub&gt; 2</sub&gt; כלי-<sub&gt; 2</sub&gt; Domains אבץ האצבע

Due to their modularity and ability to be reprogrammed to recognize a wide range of DNA sequences, Cys2-His2 zinc-finger DNA-binding domains have emerged ...