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Showing: 181 - 200 of 876 results
  1. Viral Production at Addgene

    Type
    Blog Post
    Published
    Oct. 24, 2023, 1:15 p.m.
    ...of Pennsylvania Vector Core. Transfections are performed using the transfer plasmid, a plasmid encoding...are purified by iodixanol gradient ultracentrifugation and concentrated to purity and titers adequate for...ddPCR) titration protocol (modified from Wang et al., 2018). Briefly, 293T cells are transduced with serial...PCR with primers targeting the transfer plasmid used in the transfection. PCR products are analyzed by ...cell cultures are inspected for sterility. Transducibility Some viral vectors are tested in vitro and ...images).     Figure 2: AAV Pro cells were transduced with either pAAV-Ef1a-mCherry-IRES-Cre (55634...cleared by low-speed centrifugation and then by filtration through a 0.45 µm polyethersulfone (PES) membrane...
  2. Plasmids 101: Shuttle Vectors

    Type
    Blog Post
    Published
    May 20, 2025, 1:15 p.m.
    ...mammalian analogue of bacterial transformation is transfection. In stable transfection, DNA from the plasmid is...vectors delivered by transformation and transfection and left the business of transduction to our Viral Vectors... Plasmids 101: Transformation, Transduction, Bacterial Conjugation, and Transfection Plasmids 101: Choosing...to retain the vector as cells divide. In transient transfection, the vector remains episomal, meaning it...vector replication at all. In these cases, transient transfection may be sufficient for your needs even without...called transfer vectors. The gene of interest is cloned into a shuttle vector for transfection into producer...has seen before, showing how DNA sequences are translated into amino acids. And I was astonished that the...
  3. Bacterial Toxin-antitoxin Systems as Molecular Biology Tools

    Type
    Blog Post
    Published
    Nov. 1, 2018, 12:35 p.m.
    ...required for hok translation. Here, Mok and Hok translation is coupled. Translation from the Shine-Dalgarno...more stable than the methyltransferase. When a plasmid is lost, the methyltransferase is degraded and/or...Science translational medicine 7.289 (2015): 289ra84-289ra84. PubMed PMID: 26019220. PubMed Central PMCID... by binding the GyrA subunit of DNA gyrase and trapping it in the cleaved complex. This results in DNA...ccdB gene die off and a higher percentage of transformants contain the ccdB-less construct. Other toxin-antitoxin...introduce multiple genetic modifications in the same strain. MazF expression is under control of the AOX1 promoter...composed of restriction endonucleases and methyltransferases. Restriction endonucleases cleave DNA at ...
  4. RUBY-Red Siliques

    Type
    Blog Post
    Published
    March 1, 2022, 2:15 p.m.
    ...Selectable transgene markers for plant transformation fall into two main categories: antibiotic/herbicide...presence of a transgene instead, which can’t be done if your selection method kills the transgene free individual...Arabidopsis seed following floral dip transformation next to an untransformed seed from the same plant beginning...resistance genes usually involves killing the untransformed seedlings or callus (undifferentiated plant ...For example, with CRISPR-Cas9 gene editing, transformation may be identified by resistance to an antibiotic...antibiotic. Successful editing of transformants then typically occurs in T0 plants (from callus) or T1 plants...contaminate it. I have used it for selecting transformation events and am currently planning to use it ...
  5. Antibodies 101: ELISA (Enzyme-linked Immunosorbent Assay)

    Type
    Blog Post
    Published
    Aug. 24, 2021, 1:15 p.m.
    ... the reaction of HRP with its substrate, 3,3′,5,5′-Tetramethylbenzidine (TMB). The addition of hydrochloric...coating the bottom of the well), and then its concentration is detected through visualization of an enzymatic... molecule, such as biotin. Next, a conjugated substrate is added to the wells. In the case where the detection...enzyme horseradish peroxidase (HRP). Finally, the substrate of HRP is added to the wells. This reaction produces...produces a colorimetric reaction that reflects the concentration of your target protein in each well. The reaction...Sandwich ELISA to quantitatively measure protein concentration or antibody specificity via a colorimetric reaction...Competitive ELISA to quantitatively measure protein concentration or antibody specificity via a colorimetric reaction...
  6. R Bodies: Membrane-Rupturing Microscopic Tools

    Type
    Blog Post
    Published
    April 14, 2016, 2:30 p.m.
    ...endocytosis, vesicle trafficking, or muscle contractions) are produced by orchestrated movements of networks...explore their ability to penetrate other barriers (like vasculature or extracellular matrices) in response...PMID: 3759909. PubMed Central PMCID: PMC213417. 2. Schrallhammer, M. et al. Tracing the role of R-bodies...learn a lot from Nature’s simpler solutions to transmitting forces over long distances. For instance, how...machines R bodies can repeatedly extend and contract in response to changing pH, and they can rupture...
  7. The MTA at Addgene

    Type
    Blog Post
    Published
    July 23, 2024, 2:17 p.m.
    ...the material transfer agreement, read on!  What is the MTA?  An MTA is simply a contract or agreement...Biological Material Transfer Agreement (UBMTA) is one of the most commonly used ones for transfers between academic...shine.  These types of agreements allow for centralized tracking when biological reagents are shared — both...for more information. Happy transferring!    Many thanks to our Tech Transfer team members Maura Coughlin...Addgene, then you’ve been involved in the material transfer agreement (MTA) process. Even though this process...the creation of a standardized agreement on the transfer of biological materials in 1995: the UBMTA. Because...most academic and nonprofit institutes, the Tech Transfer department is responsible for managing research...
  8. Hot Plasmids: Summer 2025

    Type
    Blog Post
    Published
    Aug. 28, 2025, 1:15 p.m.
    ...neuronal tracing, anterograde tracing poses challenges, from non-selective anterograde transport to a lack...called Simultaneous Tracking of Recombinase Activation and Clonal Kinetics (STRACK) to study stem cell...well-suited for lung cells via airway administration. AAV11 can transduce neurons for retrograde labeling, ...ATLAS: a rationally designed anterograde transsynaptic tracer. Nature Methods, 22(5), 1101–1111. https...With this proof-of-concept, they believe that the strategy will be applicable with other TnpBs and in other...Viral delivery of an RNA-guided genome editor for transgene-free germline editing in Arabidopsis. Nature Plants...While many barcoding libraries are available for tracking cell lineage, different applications require careful...
  9. SARS-CoV-2/COVID-19 Detection Methods Based on CRISPR/Cas

    Type
    Blog Post
    Published
    May 5, 2020, 1:15 p.m.
    ...and to do so, the WHO recommends one strategy: testing, tracking, and social distancing. With countries...are designed, each binding to one strand of the reverse-transcribed target sequence that are present close... the samples. First, RNA is extracted and subject to reverse transcription. This is then amplified by ...PCR using Taq Polymerase and then transcribed to provide RNA substrates for Cas13. Cas13, upon finding complementarity...block and 62°C heat block Approach: Viral RNA is extracted and subject to isothermal amplification by primers...cleaves the supplied fluorescently labelled ssDNA substrates. Upon cleavage, the fluorescence is no longer...directly using saliva without having to perform RNA extraction but that may work only if there is a high enough...
  10. Harnessing Bacterial Toxins for Allelic Exchange

    Type
    Blog Post
    Published
    Aug. 15, 2019, 12:30 p.m.
    ...rhamnose-inducible promoter, though Khetrapal et al. also demonstrated that the arabinose promoter worked...strong transcriptional terminator BBa_B1002 (from IGEM) upstream of the MCS to reduce transcriptional readthrough...Channarasappa, and Howard M. Salis. "Translation rate is controlled by coupled trade-offs between site accessibility.... PubMed PMID: 23360965. PubMed Central PMCID: PMC3748948.  Khetrapal, Varnica, et al. "A set of powerful...rely on exogenous enzymes, require multiple transformation and plasmid curing steps, and can generate ...toxins to facilitate efficient recombineering (Khetrapal et al., 2015). They created vectors for Lambda...tight (Giacalone et al., 2006). The Chen lab demonstrated excellent counter-selection which enabled very...
  11. Thoughts on the Future of Research 2015 Boston Symposium

    Type
    Blog Post
    Published
    Nov. 25, 2015, 4 p.m.
    ...benefits commensurate with work training and experience, better align trainee expectations with job outcomes...that fact that training in the academic research environment is setup to prepare trainees for further work...non-academic careers, much of the training they receive as postdocs is not transferrable to other environments. ... of trainees at low wages will still be there without restructuring. Positive Points for Trainees - Taking...information - all traits you are likely to find in graduate students and postdocs. Trainees however, need ... the mentor and this training is clearly not equitable to that of other trainees despite the fact that...temporary and defined period of mentored advanced training to enhance the professional skills and research...
  12. Viral Vectors 101: Viral Applications

    Type
    Blog Post
    Published
    April 13, 2023, 1:15 p.m.
    ...Viral delivery is attractive due to the ease of transduction in difficult-to-transfect cell types ranging...higher than traditional transfection and random genomic integration of a plasmid. Viral transduction is also...overexpression of all human transcription factors, barcoded libraries to trace cell lineage, and so much...delivered with viral vectors instead of a traditional transfection method. This is because viral systems ...integrated into the genome of the target cell or transiently expressed. It’s important to note that for all...vector can express your construct in target cells transiently or constitutively depending on the virus used...also generally less toxic to cells than transfections, preserving cell viability. Library delivery Screening...
  13. Fluorescent Proteins 101: Luciferases

    Type
    Blog Post
    Published
    July 22, 2025, 1:15 p.m.
    ...luminescent) worlds Forster Resonance Energy Transfer (FRET) is the transfer of energy from an excited donor fluorophore...Resonance Energy Transfer (BRET) works the same way, except that energy is transferred from a luminescence...membrane and deliver the substrate; however, secreted luciferase or alternative substrates can permit measurements...incompatible substrates can also allow multiplexing with experiments that supply both substrates and measure...production of light by a chemical reaction. In contrast, fluorescence occurs when a molecule is excited... Bioluminescent reporters require a chemical substrate (and sometimes cofactors) to be provided and are... they’ll keep emitting light as long as their substrate is available. Table 1 compares some general advantages...
  14. Droplet Digital PCR for AAV Quantitation

    Type
    Blog Post
    Published
    Jan. 16, 2020, 2:18 p.m.
    ...droplets is used to calculate the concentration of the sample. This concentration can then be used to calculate...possible to measure the concentration of multiple targets simultaneously. For AAV titration, you should only ...tool for quantifying AAV for some time now. When titrating AAV by qPCR, viral DNA is amplified and monitored...For these reasons, we are in the process of transitioning our titering method from qPCR to ddPCR. Droplet...needed for your PCR experiment. The process to titrate AAV by ddPCR begins with diluting the virus. It...million.  After making the dilutions, they are transferred to a new plate containing the mastermix which...place.  When the PCR is complete, a droplet reader extracts the droplets from the plate and measures the fluorescence...
  15. 15 Hot Plasmids from 2017

    Type
    Blog Post
    Published
    Jan. 9, 2018, 3:02 p.m.
    ...energy transfer) and FLIM (Fluorescence Lifetime Imaging Microscopy) applications. To demonstrate the power...caging technique to beautifully demonstrate light-dependent Gal4 transcriptional activation and Cre recombination...scientists to quickly and easily generate zebrafish transgenic lines to study neurobiology and neuorodgenerative... six fluorophores with nonoverlapping emission spectra (N- and C-terminal tags for mTagBFP, TagRFPt, EGFP...pluripotent stem cells) through the expression of transcription factors OCT3/4, SOX2, KLF4, and c-MYC is the... method for generating iPSCs to express the transcription factors from a polycistronic cassette. However...comparable experimental results. Using PiggyBac transposons, the Woltjen Lab compared different variants ...
  16. Easi-CRISPR: Generating Knock-In and Conditional Mouse Models

    Type
    Blog Post
    Published
    April 5, 2018, 12:42 p.m.
    ... Wenning Qin. Single-stranded DNA repair templates Short single-stranded DNA templates have been shown...HDR subpathway. It's traditionally been difficult to produce long single-stranded DNA, but Miura et al...perform in vitro transcription, and use the IVT product as a template for reverse transcription to create your...order to insert two loxP sites. Since two double-strand breaks are made, it is common to see deletions ...structure. Today, multiple companies offer long single-stranded DNA production services or kits, including the... the separated guide RNA components (crRNA and tracrRNA) for maximum Easi-CRISPR efficiency. Easi-CRISPR...microinjection and electroporation methods using in mouse transgenics. Designing an Easi-CRISPR knock-in allele To ...
  17. Avoiding the Dark Side of Fluorescent Protein Fusions with mOX FPs

    Type
    Blog Post
    Published
    Oct. 27, 2015, 3 p.m.
    ...via the Sec translocon." Traffic 12.5 (2011): 543-548. Pubmed PMID: 21255213. Pubmed Central PMCID: PMC3079558...[3]. You must therefore determine your cloning strategy and decide whether you will create an N- or C-...mitochondria, lysosomes or they are secreted into the extracellular milieu. Many of the resident proteins within...these compartments undergo significant post-translational modifications including glycosylation, disulfide... addition of N-glycans [9]. Both of these posttranslational modifications can disrupt FP folding rendering...and yellow moxFPs. The inherent brightness and spectral characteristics of the moxFPs are comparable to...non-optimized parental proteins. Our recent publication illustrated the quantitative increase in fluorescent signal...
  18. Hot Plasmids May 2018 - Optogenetics, Decaffeination, Biosensors, and Fluorescent Protein Tools

    Type
    Blog Post
    Published
    May 15, 2018, 12:43 p.m.
    ...changes in intracellular Ca2+ levels than the original version containing CRY2 without the extra peptide....-free drinks. Finally, they demonstrated that the caffeine concentrations in several beverages could be...networks. A major drawback of this method is the stray excitation of neighboring neurons in opsin dense... (Figure 1.) Moreover, the group was able to demonstrate that while illumination of neighboring cells ...expression in E. coli. This operon is under the transcriptional control of a strong constitutive promoter (... required enzymes, including a glutathione S-transferase homolog from a Janthinobacterium sp. Moreover...Moreover, a caffeine “addicted” E. coli strain expressing this operon can serve as a living biosensor for measuring...
  19. Nanoblades: Tiny CRISPR Ninjas for Genome Editing Difficult Cells

    Type
    Blog Post
    Published
    Sept. 26, 2019, 12:50 p.m.
    ...its ability to infiltrate cells. Options for CRISPR delivery include plasmid transfection, RNP electroporation...been used to increase retroviral transduction efficiency by neutralizing the charge repulsion between virions...results demonstrate that Nanoblades are a potential alternative method for generating transgenic mice strains...electroporation, and viral transduction; but these methods aren’t stealthy enough to gain access to some cells...Repair (HDR), CRISPR activation or repression, transgenic mouse line creation, and in vivo gene editing... non-replicative. Nanoblades are produced by transfecting the following four components into 293T cells... can also deliver Cas9 variants, such as a transcriptional activator dCas9-VPR, if these variants are ...
  20. Three Tips for Preventing Viral Plasmid Recombination in Your Samples

    Type
    Blog Post
    Published
    Sept. 14, 2021, 1:15 p.m.
    ...Pick the right strain While common E. coli strains like DH5-alpha are recA-, some strains have been engineered...suggest gel extraction to isolate the full, intact plasmid. Please see our gel extraction protocol for...Learn about the common lab E. coli strains Find tips for viral transduction  ...Repeating sequences within a plasmid can undergo intramolecular DNA recombination. This naturally occurring...recombination, one resulting plasmid carries the transgene of interest (aka the viral genome) and the other...resistance gene and origin will replicate, and the transgene will be lost. Over time, bacteria containing the...further reduce recombination. Recombinase-deficient strains like Stbl2, Stbl3, and NEB stable E. coli reduce...
Showing: 181 - 200 of 876 results