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Showing: 101 - 120 of 563 results
  1. Adenoviral Vector Production and Troubleshooting

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    Blog Post
    ...change the media (add 2-3 mL of fresh media once a week), and do NOT harvest the cells before at least 10...titer. Amplification (1-2 weeks) - The rAdV-S is used to infect more HEK293 cells and produce more rAdV ...infected cells show this “cytopathic effect.” Amplification can be repeated multiple times (2-4 rounds...creating adenoviral vector constructs. It consists of 2 plasmids: a shuttle vector (in which the transgene...Addgene’s Adenoviral Guide webpage, and references 1, 2.*Pro-Tip*: once the correct recombinant pAdV plasmid...sequenced to confirm its integrity. Initial production (2-3 weeks) - Here you’ll produce the primary recombinant...rounds) at increasing scale over the course of 1-2 weeks. Each round of amplification should result in a 10...
  2. Viral Vectors 101: Pseudotyping

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    Blog Post
    ...safely. Recently, many SARS-CoV-2 researchers began pseudotyping the SARS-CoV-2 spike protein into a lower ... et a., 2018).   Figure 2: To pseudotype with the SARS-CoV-2 spike protein, scientists encode...of vesicular stomatitis virus, HIV-2, and human foamy virus in cell lines expressing galactosyl(alpha1...spike protein’s role in infecting cell lines without using intact SARS-CoV-2 virus. Scientists have been using...Particles Produced in Human Cells Are Inactivated by Human Serum. Molecular Therapy 2:218–222 . https://doi....production uses three plasmids: (1) The transfer plasmid, (2) the envelope plasmid, and (3) the packaging plasmid... pseudotyping methods with other viruses in a BSL-2 lab instead of a BSL-3 or BSL-4 lab. For more details...
  3. SARS-CoV-2/COVID-19 Detection Methods Based on CRISPR/Cas

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    Blog Post
    ... State University. Since its appearance, SARS-CoV-2 has spread to almost every part of the world manifesting...Rapid detection of 2019 novel coronavirus SARS-CoV-2 using a CRISPR based DETECTR assay Sensitivity:10-...primers that target the E and the N2 gene of SARS-CoV-2. If the Cas12a-sgRNA complex binds to the target sequences... method has been optimized to detect the SARS-CoV-2 virus directly using saliva without having to perform...and visual detection of novel coronavirus SARS-CoV-2 Sensitivity: 4.6-11 copies/microliter of RNA targets...single-molecule sensitive. In the case of HIV-1 and SARS-CoV-2 detection, AIOD-CRISPR without preamplification was...easy-to-deploy, protocol for Cas13-based detection of SARS-CoV-2 genetic material (CREST) Sensitivity: 10 copies of...
  4. Viral Vectors 101: Virus Safety

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    Blog Post
    ...cancer. These viruses need to be handled in a BSL-2 (or BSL-2+) lab and require additional safety measures.... BSL-1. In BSL-2 labs, eye protection is required any time you have to work with BSL-2 materials, such...respiratory diseases in humans, earning this virus a BSL-2 classification. Lentivirus (a type of retrovirus) ...recommended or required in BSL-1 and required in BSL-2 labs. When working with lentivirus, many organizations...sprayed into the air. For lentivirus and other BSL-2 materials, you’ll need to use aerosol-tight caps, ...percentage of the decontaminate to be used for BSL-2 waste, and of course, if you are working with a substance...producer cell line, such as HEK-293T, production of viral particles, and transduction of a target cell line...
  5. 10 Basic tips for mammalian cell culture

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    Blog Post
    ...: 24901218. PubMed Central PMCID: PMC4047077. 2. Pagliara, Patrizia, et al. "Ostreopsis cf. ovata induces...times), depending on the cell line so old cells should be retired! Conversely, cells younger than the 3rd ...Make sure cells don't stay out too long While you’re preparing things, make sure your cells don’t stay...contaminants. Set up a routine to split cells Don’t be lazy about splitting cells, instead try to form a routine...’s best to split cells before the plates are more than 80-85% confluent because cells like their space...lactic acid (a by-product of cellular metabolism that is toxic to the cells), and need to be split very...numbers! When starting off with a new cell line, grow the cells, aliquot them into a number of vials, ...
  6. Plasmids 101: Knockout/Knock-In Plasmids

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    ...the addition of Cre recombinase (Figure 2). Figure 2: A knockout targeting vector designed to...construct. For recombination to occur in a cell, a minimum of 2 kb of sequence homology is required, but...Deliver your construct to your target cells. After recombination, exon 2 of the targeted gene will be removed... through an experiment designed to knock out exon 2 of a given gene.   Figure 1: A knockout targeting...the GFP/NeoR cassette is inserted in place of exon 2. Thus, the targeted gene is disrupted (knocked out...recombination event will remove NeoR only and leave exon 2 floxed, as seen in line 4 of Figure 4. Since the loxP...recombined cells. Recombination is a rare event, so you must select as opposed to screen for cells where recombination...
  7. The Challenges of Cell Culture

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    Blog Post
    ... York: Crown Publishers, 2010. 2. Gold, Michael. "A conspiracy of cells." State University of New York...quality work in cell culture. The problems with cell lines Simply put, the majority of cell line problems...HeLa cells, the first immortalized human cell line. He proved this by examining whether the cell lines...Cancer Cells, Marker-independent identification of glioma-initiating cells. The International Cell Line ...working cell bank has been made by a research institution (an excellent practice), or maybe cells have been...Animal Cell Culture Guide Thermofisher Guidelines for Maintaining Cultured Cells Invitrogen Cell Culture... Outreach Scientist Nick Amiss. Cell culture in the present day Cell culture is a widespread tool used...
  8. Addgene's Top Blog Posts from 2020

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    Blog Post
    ...CRISPR to detect SARS-CoV-2, including many with plasmids deposited at Addgene! 2. DNA Purification Without...detection methods, synthetic nanobodies, SARS-CoV-2 protein expression, and more. We also highlighted ...empty backbones, fluorescent protein tags, SARS-CoV-2 plasmids, etc. It is our hope that by providing cloning...RNA and extracting RNA without a kit. 3. SARS-CoV-2/COVID-19 Detection Methods Based on CRISPR/Cas by ...multiple plasmids in one cell, it might be that you can't stably maintain them in the cell. This blog post features...
  9. Lambda Red: A Homologous Recombination-based Technique for Genetic Engineering

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    Blog Post
    ...generate 2 possible products: 1) a partially dsDNA duplex with single-stranded 3’ overhangs or 2) if the...but these cells are prone to mutations and will have more unintended changes to their genomes. 2) Designing...recombineering system has three components (Figure 1): 1) Exo, 2) Beta, and 3) Gam. All three are required for recombineering...generic lambda red recombineering experiment (Figure 2). In the following sections, key steps that differ...confirmation of recombinant clones.    Figure 2: Overview of using Lambda Red recombineering system...pairs of homology to the targeted insert site (Figure 2, top).  These primers are typically ~70 nucleotides...bacteria that has key MMR proteins knocked out or 2) specially design ssDNA oligos to avoid MMR: 1) E....
  10. Luciferase Plasmids

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    Collection
    ...and Venus fluorophore to Troponin C Ca 2+ binding domain. Nano-lanterns , Enhanced Nano-lanterns , and...transfection Feng Zhang 21471 pLenti PGK V5-LUC Neo (w623-2) Firefly PGK Lentiviral expression of firefly luciferase...Expression of firefly luciferase from a cell-free mammalian cell lysate Marcel Bruchez 108542 pLenti-EF1a-Luciferase-IRES-Blast-WPRE...not secreted, so cells must be lysed or the substrate must be delivered intracellularly in order to measure... viral infection efficiency, to study changes in cell physiology, or as a reference level of expression...interactions , protein dimerization , endosomal escape of cell-penetrating peptides , and more. nLuc/cLuc for split...Resonance Energy Transfer (BRET) CalFlux VNT : An intracellular calcium sensor created by fusing NanoLuc® and...
  11. Antibodies 101: Fab Fragments

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    Blog Post
    ...fragments that retain antigen binding (Figure 2):  F(ab')2 - These fragments are produced by proteolytic... multiplexed super-resolution microscopy. Cell Rep Methods 2(10):100301. https://doi.org/10.1016/j.crmeth...fragments are produced by mild reduction of F(ab')2 fragments, which reduces the hinge region disulfide...Variable (scFv). Size: ~25 kDa.   Figure 2: Comparison between a full IgG antibody and common...advantages, though with some caveats.  First off, F(ab’)2 fragments are bivalent, so may have higher avidity...or Fab fragments. Higher avidity means that F(ab’)2 fragments may have overall stronger interaction with...Clinical Prospects of Antibody Fragments. Antibodies 8(2):28. https://doi.org/10.3390/antib8020028    Wessel...
  12. Viral Vectors 101: Producing Your rAAV

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    ...digital PCR. Human Gene Therapy Methods, 25(2), Article 2. https://doi.org/10.1089/hgtb.2013.131 Lock,... and keep the cells happy. Harvesting virus Once you have transfected your cells, wait 2–5 days and then...quantification of adeno-associated virus serotype 2-derived inverted terminal repeat sequences. Human ..., R., & Kleinschmidt, J. (1999). Titration of AAV-2 particles via a novel capsid ELISA: Packaging of genomes... genomes can limit production of recombinant AAV-2. Gene Therapy, 6(7), Article 7. https://doi.org/10.1038...Characterization of a recombinant adeno-associated virus type 2 Reference Standard Material. Human Gene Therapy, 21...however, you’ve collected the producer cells, you’ll need to lyse the cells to let the virions out. We recommend...
  13. Plasmid Preps: Different Purity, Different Quantities, Different Uses

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    Blog Post
    ...electrocompetent cells is minimal (picogram range). It can be extracted from small bacterial cultures (i.e. 2-3 ml...ratios measured at 260 and 280 nm should fall ~1.8 - 2 and give scientists an indication of purity versus...contaminants. The 260 and 230 nm ratios should fall ~2 - 2.2, and provide an indication of purity versus ...hydrochloride used during plasmid extraction. Figure 2: Use cloning grade DNA for direct cloning of your ...lipopolysaccharide of the cell wall of Gram negative bacteria like E. coli that affects tissue culture cell line viability...introduces transformation grade plasmids into a bacterial cell. Transformation grade DNA  Transformation is ...Figure 3: Need to introduce plasmids into mammalian cells? Use transfection grade DNA. Transfection is ...
  14. Hot Plasmids - October 2022

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    Blog Post
    ...GEVIs (called ASAP 1 and 2), they found an indicator that is optimized for 2-photon imaging of voltages...challenges in 2-photon in-vivo imaging of voltage fluctuations. Image credit: Liu Z, et al. Cell. 2022.  ...suitable for in vivo optogenetic use.   Fig. 2: A) HcKCR1 is highly selective for K+ over other Na...slice of HcKCR1-EYFP and tdTomato expressed layer 2/3 neurons in mouse. C) Action potential frequencies...two-photon microscopy. Cell, 18, 3408 - 3425.e29. (2022). https://doi.org/10.1016/j.cell.2022.07.013.   ...specific for human c-myc proto-oncogene product. Mol Cell Biol. Dec;5(12):3610-6.(1985). doi: 10.1128/mcb.5.12.3610...
  15. Brain Initiative Collection

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    ...Gordon Fishell 83899-AAV1 pAAV-mDlx-GCaMP6f-Fishell-2 GCaMP6f expression in forebrain GABA-ergic interneurons...Gordon Fishell 83899-AAV9 pAAV-mDlx-GCaMP6f-Fishell-2 GCaMP6f expression in forebrain GABA-ergic interneurons...Gordon Fishell 83899-AAVrg pAAV-mDlx-GCaMP6f-Fishell-2 GCaMP6f expression in forebrain GABA-ergic interneurons...real-time interrogation and monitoring of brain cells and circuits during behavior. Long desired by researchers...A somatic channelrhodopsin, which enables single cell, single millisecond resolution optogenetics. Human...A somatic channelrhodopsin, which enables single cell, single millisecond resolution optogenetics. Cre-dependent...genetically encoded dopamine sensor RdLight1 in mammalian cells. Lin Tian 125708-AAV9 pAAV-hSynapsin1-RdLight1 Expresses...
  16. Rosella: A Fluorescent pH-Biosensor for Studying Autophagy

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    Blog Post
    ...Table 2 for more details on the effect of pH on the fluorescent properties of Rosella.   Table 2: Effect...in yeast. Autophagy,4(2), 205-213. doi:10.4161/auto.5331. PubMed PMID: 18094608 2. Sargsyan, A., Cai, J...environment like the vacuole or lysosome. See Table 2 for a summary of what color fluorescence Rosella emits...fluorescence accumulates in the vacuole. See Figure 2 for an example of what fluorescence looks like for... Mammalian Autophagy Research. Cell,140(3), 313-326. doi:10.1016/j.cell.2010.01.028. PubMed PMID: 20144757...analyzing autophagy of cytosol and organelles in yeast cells. Autophagy (Greek for “self-eating”) is induced ...radio-labeled long-lived proteins as a proxy for autophagy. Cells are cultured with isotope-labeled amino acids for...
  17. Plasmids 101: Secondary Nanobody Toolbox

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    ...Journal of Cell Biology. PubMed PMID: 29263082 Find plasmids from this publication at Addgene. 2. Bates,...antibody has an antigen binding site for a total of 2 binding sites per antibody. C) IgG’s are big enough...enough that multiple labels (green circles in figure 2 below) can be attached to each antibody. But being...displacement Require separate incubation of 1° and 2° Must use different species and/or different IgG ...Greater resolution due to lower label displacement 2° incubation can be skipped by pre-binding to 1° ...a fluorescent tag and the target antigen to about 2 nm, which can lead to higher resolution for super-...subclass.   Express the Nanobody In Bacteria: Table 2 also has a link to the plasmid you’ll need to express...
  18. Tips for a 1st Time CRISPR User (by a 1st Time CRISPR User)

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    ... a range of reasonable MOIs. 2. Create a monoclonal Cas9-expression cell line. Especially if you’re doing...(Figure 2) and I was surprised at how variable Cas9-expression was across the different cells (Figure ...Overview: By Western blotting (Figure 2, pool), I knew the cells expressed Cas9, but I didn’t know what...knockouts and knockins in human somatic cells. Nature Protocols 2007; 2(11): 2734-46. PubMed PMID: 18007609...despite having active Cas9 (see tip 2). Pro-Tips 1. To quantify Cas9 activity using this assay, you really...Western blotting against GFP expression, but I didn’t. 2. In the original publication they see GFP expression...and I got clear bands using the conditions above. 2. Design your primers so that the digestion site isn...
  19. The Materials Science of Optogenetics Experiments

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    ...different steps and materials required for each [1, 2]. This protocol [3] provides, in exquisite detail,...stimulation         In the video above, Channelrhodopsin 2 (Chr2) has been expressed in the motor cortex of a...lasers are relatively cheap and will run you about $2-3,000/laser. However, an important caveat is that ... the light-gated cation channel, Channelrhodopsin 2 (ChR2), exists in several states: closed/light receptive...PMID: 21628464; PubMed Central PMCID: PMC3138296. 2. Sparta DR, et al. Construction of implantable optical...board, Jacqueline N Crawley  [et al]. 2012;Chapter 2:Unit2 16. doi: 10.1002/0471142301.ns0216s58. PubMed...Pharmacology and Optogenetics. Cell 162.3 (2015): 662-674. doi: 10.1016/j.cell.2015.06.058. Pubmed PMID: 26189679...
  20. Multiplexed Capture of Promoter-enhancer 3D Chromatin Structures Using CRISPR

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    ...eGFP tag, and 2) gRNAs Number of loci targeted One Many Sample type(s) Cell lines Cell lines, primary...Expression system Stable cell line expressing 1) FLAG-biotin-tagged dCas9, 2) BirA, and 3) one or more...Originally published Dec 7, 2017 and updated Jul 2, 2020. Promoters may be the star of gene regulation...sequence targeted in the experiment. Figure 2: Comparing CAPTURE and CAPTURE 2.0.     Original...identified and the level of on-target enrichment. 2. Determining the spatial and hierarchical organization...Cytogenetics, 11. https://doi.org/10.1186/s13039-018-0368-2  Liu X, Zhang Y, Chen Y, Li M, Zhou F, Li K, Cao H... of cells (~5x107). Together, these two requirements prevent the use of CAPTURE with primary cells or ...
Showing: 101 - 120 of 563 results