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Showing: 61 - 80 of 597 results
  1. Plasmids 101: TOPO Cloning

    Type
    Blog Post
    Published
    Oct. 27, 2016, 2:30 p.m.
    ... strand and a tyrosyl residue of topoisomerase I (1). If a 5′ hydroxyl group from a different DNA strand...Let’s break down the steps needed for TOPO cloning: 1. Create Your PCR Product: Design standard primers ...mind that Taq polymerase has an error rate of about 1 in 3,500 bases. Typically polymerases with proofreading...enzyme and Taq, with Taq used in an excess ratio of 10:1. Gel purify your PCR product and incubate it with ...you to see colonies within 8 hours. References: 1. Shuman S. "Recombination mediated by vaccinia virus...insert comes from using Taq polymerase for the amplification step since Taq polymerase leaves a single deoxyadenosine...rejoining supercoiled DNA ends to facilitate replication. The TOPO technique specifically uses Vaccinia...
  2. Antibodies 101: Designing Your First Flow Panel

    Type
    Blog Post
    Published
    May 28, 2024, 1:45 p.m.
    ...marker. Looking at Table 1, we can recognize a couple of fluorophores from Figure 1. For example, the chart...efficient (i.e., happen most of the time). Figure 1 shows a graph from the BD® Spectrum Viewer, outlining...Resonance Energy Transfer (FRET).   Figure 1: Emission spectra and respective colors of a few commonly... the brightness of individual fluorophores. Table 1 describes the brightness of a few commonly used fluorophores...Brighter fluorophores have a stronger signal. Table 1: Degrees of brightness for a few commonly used fluorophores...blue laser excites at a wavelength of 488 nm (Table 1), which is near a local maximum of PE's excitation...Knowing that the red laser excites at 640 nm (Table 1), while comparing the two fluorophore's excitation...
  3. AAV Titers: Where Do They Come From And What Do They Mean?

    Type
    Blog Post
    Published
    Nov. 15, 2017, 3 p.m.
    ...near-perfect physical-to-infectious particle ratio of 1:1 (Zeltner et al., 2010). However, for recombinant ...preparations are genome-containing (Figure 1).    Figure 1: Electron micrograph of an Addgene AAV...reported a physical-to-infectious particle ratio of 50:1 (Zeltner et al., 2010). The specific infectivity of... lot (if we still have it available). References 1. Fagone, Paolo, et al. "Systemic errors in quantitative... Human Gene Therapy, Part B: Methods 23.1 (2011): 1-7. PubMed PMID: 22428975. PubMed Central PMCID: PMC3640491...the other to guess a category by listing off things that fall into that category? Okay, let’s play. I’...’ll list the examples and you try to guess the category: ELISA...qPCR...Digital droplet PCR...DNA dot ...
  4. Scientific Reproducibility - Focusing on Solutions at the Minisymposium on Reproducibility

    Type
    Blog Post
    Published
    May 18, 2018, 7:32 p.m.
    ... handed out at the event). Program 0 - 1:24 - Intro 1:24 - 29:31 - Reproducibility Overview - Jeffrey... 49:45 0 1:18:45 - Reagent Development - Steven C. Almo, Institute for Protein Innovation  1:18:45 - 2...reproducibility As Jeffrey Flier points out in his talk (1:24 - 29:31), there are a variety of ways of defining...enterprise towards greater reproducibility. Cause 1: Inability to repeat previously performed experiments...the Institute for Protein Innovation (IPI) (49:45 - 1:18:45), there are also initiatives to create more ...found. Consider the hypothetical situation in Figure 1 where many scientists are performing similar experiments...someone has replicated it precisely. You can find a great discussion of different types of replication in Nosek...
  5. 5 Uncommon Ways to Gain Career Skills During an Uncommon Time

    Type
    Blog Post
    Published
    Oct. 20, 2020, 1:15 p.m.
    ...need a job. Start now. Informational interviews are 1:1 discussions with someone who has interesting experiences...conversation builds a relationship for the future and the 1:1 format is good for everyone including those that ...out-of-the-box ideas that might jump start your learning. 1. Create a peer mentoring group We don’t all get the...be a time when you need to speak publicly to communicate your work. One of my 10 tips for giving a great...; Graduate Student Funding Opportunities Open Education Database: 100 Places to Find Funding For Your ...
  6. A Primer on Optogenetics: Introduction and Opsin Delivery

    Type
    Blog Post
    Published
    Sept. 10, 2015, 2:30 p.m.
    ...Jacqueline N Crawley  [et al]. 2012;Chapter 1:Unit 1 20 1-18. doi: 10.1002/0471142301.ns0120s59. PMID:...mutually exclusive) commonly used in optogenetics: 1) electrophysiology and 2) behavioral experiments. ...can be broken down broadly into three main steps: 1) Selection and expression of your opsin of choice ...reviews for a discussion of the different variants [1, 2, 4]. And, of course, the best way to learn about...monitor expression at various time points (e.g. every 1-2 weeks over 8 weeks) in order to determine the optimal...follow him on Twitter @derekpsimonphd.    References 1. Tye KM, Deisseroth K. Optogenetic investigation of..., Jacqueline N Crawley  [et al]. 2013;4(435):4 35 1-4  20. doi: 10.1002/0471142301.ns0435s65. PMID: 25429312...
  7. REPLACR Mutagenesis: Replacing In Vitro Recombination Methods

    Type
    Blog Post
    Published
    Feb. 10, 2016, 3:30 p.m.
    ...deletions, point mutations PCR Reactions 1 1 1 per fragment 1 per fragment In vitro Assembly No No Yes...methods for site directed mutagenesis   References 1. Trehan, Ashutosh, et al. (2016). “REPLACR-mutagenesis... the steps of gel purification and in vitro recombination. Across all modifications described in Trehan...mutations, large deletions/insertions require complicated, often costly in vitro assembly methods. A new...recombination machinery, which facilitates easy genetic modification by homologous recombination. In most recombineering...
  8. Controlling for Off-target Effects with a New Genome-wide CRISPR Screen Design

    Type
    Blog Post
    Published
    Sept. 13, 2018, 1:55 p.m.
    ...holds true in genome-wide screens.   Figure 1: Summary of the advantages of the new approach to ... in both screens, with the growth screen having a 1% false discovery rate and identifying >88% of previously...in Morgens et al. contains three types of guides: 1) targeting guides (blue), which target all protein-coding...off-target sites was profiled. Guides with exact or 1-bp mismatch off-targets had greater toxicity than ...characteristics that influence gRNA off-target activity: 1) mismatches closer to the PAM are less tolerated than.... When comparing the toxicity of guides that have 1-bp mismatch off-target sites, short guides had reduced...Knockout Library are available from Addgene! References 1. Morgens, David W., et al. "Genome-scale measurement...
  9. Plasmids 101: Control Plasmids

    Type
    Blog Post
    Published
    April 9, 2015, 3:29 p.m.
    ... and investigation. References: 1. The problem of pseudoreplication in neuroscientific studies: is it...Gene X using shRNA expressed from a plasmid   Figure 1: Expression Level of Gene X The results shown above...Referring back to the experiment associated with Figure 1, the independent variable is the shRNA. Therefore ...the protein.   In analysis of the result in Figure 1, an internal control, such as the GFP-expressing Plasmid...control and is consistent with the result in Figure 1 could look like this: Figure 2: Expression of Plasmid...plasmid.  Let us now revisit our experiment. In Figure 1, it appeared as though the shRNA did not knock down...two types of replicate controls: technical and biological. In general, technical replicates can be thought...
  10. Celebrating Outstanding CRISPR/Cas9 Achievements at the Dr. Paul Janssen Award Dinner

    Type
    Blog Post
    Published
    Sept. 15, 2014, 6:05 p.m.
    ...the result was a simpler 1 protein - 1 RNA system.  Dr. Charpentier advocated for the crucial role of ...minutes, which was fun to watch. A simpler 1 protein - 1 RNA system Drs. Dounda and Charpentier met at...adaptive bacterial immunity and its potential applications in rewriting the genome. Their award acceptance... same Polish sub-dialect making their Skype communications extra fun) who shared first authorship on their... area will accelerate the launch of clinical applications. During the panel discussion, Dr. Mello took...for billions of years (…) Bacteria are really sophisticated”.     New to CRISPR/Cas9 Technology? Learn ...
  11. Antibodies 101: Producing Recombinant Antibodies

    Type
    Blog Post
    Published
    Aug. 13, 2024, 1:15 p.m.
    ...materials have been washed away (Figure 1).      Figure 1: The steps of rAb production. Created ...EBNA1 Cells. Methods Mol Biol. 2018;1850:1-16. doi: 10.1007/978-1-4939-8730-6_1. PMID: 30242676. Frenzel...Neuroscience Research. Curr Protoc Neurosci. 2020 Dec;94(1):e106. doi: 10.1002/cpns.106. PMID: 33151027; PMCID...detection, and control. Int J Pharm. 2018 Oct 25;550(1-2):251-268. doi: 10.1016/j.ijpharm.2018.08.043. Epub...addgene.org Addgene's Antibody Purification Protocol Addgene's Video Antibody Purification Protocol Addgene's Antibody...cells can perform human-like post-translational modifications that bacterial and most yeast cells cannot. ...production system may depend on what downstream applications you are planning, cost, and the amount of protein...
  12. Droplet Digital PCR for AAV Quantitation

    Type
    Blog Post
    Published
    Jan. 16, 2020, 2:18 p.m.
    ...range of titers. We usually dilute our samples 1:6 million to 1:25 million.  After making the dilutions, they...note that the dynamic range of the ddPCR is between 1 and 100,000 genome copies (GC) per reaction. Since...In the image to the right, there is approximately 1 positive copy per microliter in the no template control...elongation time to 2 minutes and the denaturation time to 1 minute has been shown to increase droplet separation...diagnosis." Emerging microbes & infections 7.1 (2018): 1-9. PubMed PMID: 29691363. PubMed Central PMCID: PMC5915492...take to achieve a clean NTC: Have a dedicated bench with a dedicated set of pipettes for ddPCR set-up. .... Each droplet contains the ingredients for amplification of the target DNA. This partitioning reduces...
  13. Negative Can Be Positive: Open AAV Data with Addgene

    Type
    Blog Post
    Published
    Sept. 6, 2022, 1:15 p.m.
    ...across scientific disciplines. Scientific Data, 8(1), 1–11. https://doi.org/10.1038/s41597-021-00981-0 Wright...occurrence during vector purification and formulation. Molecular Therapy, 12(1), 171–178. https://doi.org...excellent at infecting our target neurons (Figure 1). However, this one set of experiments didn’t provide...yet none of that data was published.    Fig. 1: Testing of three different AAV serotypes (AAV1, 8...Stimulation. Frontiers in Human Neuroscience, 14(December), 1–12. https://doi.org/10.3389/fnhum.2020.578687 Additional...caudal NST. (A-C) Low-magnification images showing viral spread. (D-F)  High-magnification images immuno-stained... right AAV for your system or to successfully replicate published works. Of particular importance to these...
  14. CRISPR Antimicrobials

    Type
    Blog Post
    Published
    May 3, 2016, 2:30 p.m.
    ..., they used 1-2 CRISPR crRNAs targeting sequences found only in certain bacteria (Figure 1). Citorik et...from 50% to 11% in just 24 hours.   Figure 1: Single-phage strategies for bacterial CRISPR targeting...genome, and it carries CRISPR machinery targeting 1) the given resistance gene and 2) a second lytic phage...the fight against bacterial superbugs. References 1. Citorik, Robert J., Mimee, Mark, and Timothy K. Lu...Targeted Bacterial Population Editing.” Cell Syst. 1(3):187-196. (2015). PubMed: PMID 26973885. Additional...containing a phage origin of replication that can be packaged into replication-incompetent phage particles...essential processes: cell wall synthesis, DNA replication, or protein synthesis. Because they target such...
  15. Quick Guide to All Things Lentivirus

    Type
    Blog Post
    Published
    March 21, 2017, 2:30 p.m.
    ...family including human immunodeficiency virus type-1 (HIV-1), can infect both dividing and non-dividing cells...have been devoted to develop efficient and safe HIV-1-derived lentiviral vectors due to their ability to...lentiviral vectors consisted of three plasmids encoding 1) the lentiviral vector genome which was composed of...desired gene (transfer vector plasmid), 2) the HIV-1 genome containing all viral genes with the exception...generation because this vector requires only three HIV-1 genes (gag, pol, and rev) for production. Third generation...several protocols that have been described (protocol 1, protocol 2, protocol 3) to find the one that will...to additional protocols and plasmids.  References 1. Miller, A. DUSTY, and C. A. R. O. L. Buttimore. "...
  16. SciComm with the Experts at Science in the News Part 1

    Type
    Blog Post
    Published
    March 16, 2017, 1:06 p.m.
    ...Science Communication Conversation in Science Communication The Purpose of Science Communication #1 Mistake...think about communicating science. Listen to the interview with Science in the News, Part 1 Podcast breakdown...supporters of science communication. To help you think about ways to effectively communicate your science, we...News at Harvard University. Effective science communication is required to promote public support for research... organization that works to promote science communication. Science in the News hosts a podcast, seminars...That’s right, #ActualLivingScientists, eager to communicate their science. In this first half of our two-...Mistake Scientists Make when Communicating with Non-Scientists How to Approach Different Audiences Listen...
  17. Technical Design of a Western Blot

    Type
    Blog Post
    Published
    Aug. 22, 2024, 1:15 p.m.
    ...Tris-tricine 2.5–40 kDa Tris-tricine 30 V, 1 hour or 100 V, 1–2 hours Good separation, quality, and stability...lot to cover, so let's dive in!      Figure 1: The technical decisions to make when designing a ...assay. The most common options are 4 °C overnight or 1–2 hours at room temperature (RT). Most people choose...overnight at 4 °C and their secondary antibody for 1–2 hrs at room temperature, which allows them to reduce...weight of the proteins you’re interested in. Table 1 lists the most common types of gels for SDS-PAGE running...gel chemistry and/or specialty gel options. Table 1: Types of gels  Gel Type Protein sizes Running... Tris-glycine 6–400 kDa Tris-glycine 100 V, 1–2 hours Easy and cheap to handcast Short shelf-life...
  18. Getting to Know Expansion Microscopy

    Type
    Blog Post
    Published
    June 20, 2023, 1:15 p.m.
    ...protocols. A typical ExM protocol (Fig. 1) follows this structure: Step 1: fix (and maybe label) your sample...microscopy. Nat Biotechnol 1–12. https://doi.org/10.1038/s41587-022-01546-1  Mikhaylova M, Cloin BMC, ...just adding water.)  Step 5: Image   Figure 1: The ExM process allows you to physically magnify ...16:71–74. https://doi.org/10.1038/s41592-018-0238-1  Klimas A, Gallagher BR, Wijesekara P, et al (2023...with an abundance of protocols and examples of applications from across disciplines now available. In this...experiment or evaluating ExM images in a new publication.         Why Expansion Microscopy?  Traditional...microscopes sounds great, right? But there is always a catch - some limitation of the technique that users should...
  19. Plasmids 101: Gateway Cloning

    Type
    Blog Post
    Published
    Jan. 12, 2017, 3:30 p.m.
    ...recombination sites (attL-left- and attR-right-, Figure 1). Under certain conditions, the attL and attR sites...regeneration of attP and attB sites.   Figure 1: Lambda phage integration and excision reactions. ...expression of the human KRAS gene in mammalian cells. STEP 1: Generate an Entry Clone There are a few different...could use a vector like pLenti CMV Puro DEST (w118-1) or the doxycycline-inducible pLIX_403. The chosen...the generation of the expression construct in only 1 day, as opposed to 2+ days with traditional restriction... Find Gateway cloning plasmids here! References 1. Chee JY, Chin CF (2015) Gateway Cloning Technology...attP sites of the donor vector. This reaction is catalyzed by the BP Clonase enzyme mix and generates the...
  20. Viral Vectors 101: What is a Virus (and a Viral Vector)?

    Type
    Blog Post
    Published
    Aug. 18, 2023, 4:15 p.m.
    ...Virus Replication. Essential Human Virology, 49. https://doi.org/10.1016/B978-0-12-800947-5.00004-1 Taylor... an envelope are called enveloped viruses (Figure 1). Like bacteria, only a tiny fraction of viruses are...are pathogenic (Balloux & van Dorp, 2017). Figure 1: A non-enveloped virus (left) and an enveloped virus...create far safer viral vectors that can be used in BSL-1 or BSL-2 labs. Viral vectors are viruses that have...methods of replication. In fact, an entire classification scheme, known as the Baltimore replication classes...that in a bit! Viral genomes and replication When it comes to replication, viruses tend to march to the ...developed around how they replicate (Figure 2). Figure 2: Baltimore replication classes. Image credit: ...
Showing: 61 - 80 of 597 results