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Showing: 201 - 220 of 763 results
  1. The Crispr Babies Saga Shows the Need for Action, Not More Delays

    Type
    Blog Post
    Published
    Dec. 20, 2018, 1:15 p.m.
    ...attempt to create gene-edited babies. Several hours later, the scientist, Jiankiu He, confirmed that two such...editing techniques that are sufficiently safe to manipulate an embryo—even if it’s not necessarily via CRISPR...mtDNA transfer options being investigated; A UK regulatory body tasked two separate non-governmental groups...three branches – a private funder, government regulators, and an independent ethics council – all worked... process of good research practice: computer simulations, in vitro research, animal models, and several...question we are left with is not “what is the translational pathway for CRISPR/Cas9 research” but whether...stop punting decisions on scientific, ethical, regulatory, and general public consensus to the next meeting...
  2. The Power Behind NGS Plasmid Validation: seqWell

    Type
    Blog Post
    Published
    April 19, 2017, 3:25 p.m.
    ...DNA from each well of a 96-well plate. Then, samples from several plates are pooled together to create ...sequencing to validate these constructs, as the relatively low cost and quick turn-around time of Sanger... sequential “pooled library prep”, in which a relatively large number of samples are subjected to a DNA-barcoding...samples individually, plexWell™ reduces every 96 well plate to a single tube after the first tagging step. As... samples (e.g. a collection of 96 plasmids on a plate) will typically have a wide range of input quantities... from plexWell™ NGS data. Once Addgene produces plates of plasmid DNA, they are shipped to seqWell, where...
  3. Synthetic Photobiology: Optogenetics for E. coli

    Type
    Blog Post
    Published
    Sept. 8, 2015, 2:30 p.m.
    ...consist of a histidine kinase that phosphorylates a response regulator (RR). TCS-induced responses are varied... chromophore activates the response regulator via phosphorylation, promoting transcription of a GFP reporter...2005, when Tabor was working in Voigt's lab. Years later, these classic systems continue to be optimized ...the chromophore activates the RR (OmpR) via phosphorylation, promoting transcription (see figure below)...spread across three plasmids, with the response regulator encoded in the genome. To make the system less...
  4. Synthesized by Ginkgo Bioworks, Shared by Addgene: SARS-CoV-2 Plasmids for Many Expression Systems

    Type
    Blog Post
    Published
    May 19, 2020, 1:15 p.m.
    ...glycoproteins and other proteins that require post-translational modification may not be easily expressed in ... E. coli and S. cerevisiae expression vectors in late March. The first set of 383 constructs went online...control processes. For the many other COVID-19 related plasmids in our collection, we’ve relied on Sanger...first pass QC. The lab team manually transforms, innoculates, and performs DNA minipreps for small batches...scientists prepare Sanger reactions by mixing this isolated plasmid DNA with appropriate sequencing primers...mutation.  Once the samples arrive, each group of plates will have select samples prepared and screened ...intensive screening and the use of high throughput platforms, Addgene and Ginkgo are striking a balance by ...
  5. GCE4All: Making Genetic Code Expansion Accessible

    Type
    Blog Post
    Published
    June 15, 2023, 1:15 p.m.
    ... an unnatural amino acid in translation (Noren et al., 1989). In the late nineties, this was developed...factors can negatively impact both translation and fidelity of translation, leading to system-wide effects...which can help determine structure and function relationships or, in more practical applications, allow a ...non-interacting with) the cells’ own natural translation machinery; these are often incorporated into ... any of a huge variety of ncAAs to study the relationship between structure and function…if you can get...
  6. REPLACR Mutagenesis: Replacing In Vitro Recombination Methods

    Type
    Blog Post
    Published
    Feb. 10, 2016, 3:30 p.m.
    ...PCR amplify the template plasmid. The parental, nonmutated DNA is digested with methylated DNA-specific ... a given disease. CRISPR has made genomic SDM relatively straightforward, but plasmid-based SDM has lagged...DNA-specific enzyme DpnI, and the nonmethylated PCR products are then transformed into E. coli to undergo nick repair...repair. This method can work well, but poor template digestion can result in a high number of background...mutations, to amplify both strands of a plasmid template. In addition to containing the mutations, the ...After being treated with DpnI to digest away the template plasmid, these PCR products are directly transformed...
  7. A Practical Guide to Optimizing AAV DIO and FLEx Vector Expression

    Type
    Blog Post
    Published
    Nov. 2, 2021, 1:15 p.m.
    ...particles or relatively short expression times, where as others, such as hSynapsin, are relatively weak and...sites and the open reading frame is inverted in relation to the promoter, hence the name, double-floxed...homologous pairs, and that the degree of homology is correlated with the level of spontaneous recombination. ... etc.) and even neuronal phenotype in a mixed population (Burger, C. 2004, Aschauer, DF. 2013, O’Carroll...differences in the expression of receptors, post-translational modifications, and other factors that AAV utilizes...this study were packaged at Addgene and had a relatively low recombination rate (0.1% and 0.13% respectively... Novel Next-Generation Sequencing and Analysis Platform to Assess the Identity of Recombinant Adeno-Associated...
  8. RNA Interference in Plant Biology: New Tools for an Old Favorite

    Type
    Blog Post
    Published
    Oct. 27, 2020, 1:15 p.m.
    ... target required physical isolation of the visually identified subpopulation. For traditional cell culture...nucleotides of double-stranded RNA (dsRNA) results in downregulation, or “silencing,” of any gene that contains ... through targeted mRNA degradation, blocking translation, or chromatin modifications of complementary ...hairpin RNA, or artificial microRNA). Using a DNA template for the RNAi trigger is the most prevalent method...silencing efficiency and labor-intensive processes to isolate RNAi plants. With a visual reporter of RNAi, phenotypes...culture, enriching your active RNAi subpopulation can be easily achieved through fluorescence-activated...culture can be harvested instead of microscopic isolation. The plasmids required to conduct an APT-based...
  9. Antibodies 101: Validation

    Type
    Blog Post
    Published
    March 24, 2022, 1:15 p.m.
    ...despite the manipulation. Additionally, not all sample types are amenable to genetic manipulation, nor can...your target then you would expect to see good correlation between the levels of target detected in both...both methods. These approaches have relatively low sensitivity, which can be problematic if you are trying...need to be aware of any possible alternative translation start sites or alternative splicing that could...also influence antibody binding by altering the relative concentration of potential antibody binders and... targeting a different epitope, and look for correlation between the results. Using antibodies against...cytometry using both antibodies, as well as a third unrelated antibody as a negative control (A). The two antibodies...
  10. Finding Your Science Policy Path

    Type
    Blog Post
    Published
    Sept. 22, 2020, 1:15 p.m.
    ... diplomacy and international relations, advocacy, and writing legislation (see Figure 1 for career map... give advice and guidance to those that ask. Relationship building is key in science policy. Luckily, ...happy hours that you can attend to help build relationships.  Reach out to a science policy professional...can manifest via research and data gathering, regulatory efforts, policy implementation, program management... It occurs in a government setting: drafting legislation, making rules, and implementing the policy within...company who decides how they are going pursue regulatory approval for a new product or a well-endowed ...But some are also open to individuals from mid- to late-career backgrounds. In fact, many of my AAAS STPF...
  11. Human Germline Editing Using CRISPR

    Type
    Blog Post
    Published
    Aug. 10, 2017, 2:19 p.m.
    ..., and electroporated them with an ssODN repair template in induced pluripotent stem cells made from the...fertilization. Since Ma et al. designed a repair template with two synonymous mutations to distinguish it...were able to distinguish between repair from the template vs repair from the maternal MYBPC3 allele. Interestingly...from the single-stranded oligonucleotide (ssODN) template supplied by Ma et al., but instead from the mother...repair proceeded through NHEJ rather than HDR. In later characterization studies, the edited embryos proceeded...embryos to undergo editing using the provided ssODN template. In fact, this finding led the authors to title...proceed with caution and with proper oversight from regulatory and ethics committees comprised of individuals...
  12. Rabies and Neuronal Tracing

    Type
    Blog Post
    Published
    May 29, 2018, 1:51 p.m.
    ...the jobs they perform. This became foundational later on when we studied biological processes, like how...selectively infect a genetically defined cell population. While the EnvA genetic sequences are supplied...complex control of specifically defined neuronal populations. In one study, RABV monosynaptic tracing was ...neurons came from nearby neurons. It wasn’t until later time points that longer-range connections were seen...identify inputs to two major dopaminergic cell populations in two specific brain regions (Watabe-Uchida ...differences in the inputs to each of the two populations could be used to explain the differences in the... the functions of these two neuronal populations. Overall, this study laid the foundation for how different...
  13. Educational Planarian Tools for Teaching Developmental Biology Techniques

    Type
    Blog Post
    Published
    May 24, 2018, 1:20 p.m.
    ...activity or their translation disrupted through physical blocking of the translation machinery. In the...gene expression and functions of key regeneration-related genes in four inexpensive and commercially available...transcription to create dsRNA. Students can produce DNA templates via PCR off of the same plasmid and use these ...expression changes through time or after genetic manipulation. The technique involves using synthetically ...create synthetic riboprobes off of linearized DNA templates which they can easily generate off of a circular... was first discovered and characterized in an unrelated worm (C. elegans) [2]. Delivering dsRNA matching...
  14. Plasmids 101: Modular Cloning

    Type
    Blog Post
    Published
    March 12, 2024, 1:15 p.m.
    ... cellular behaviors requires making complex manipulations to cells. For example: in a cell there are proteins...other proteins and with DNA, and these complexes regulate the transcription of specific genes. What if one... one of those genes coded for a protein that regulated its own transcription, or the transcription of ...These interactions yield a cellular phenotype, translational output, etc., which can support a larger cellular... is made, modified (sometimes many times), and isolated afterwards. To engineer these production pathways... them to these organisms via another optimized platform. Gene Stacking As the name implies, gene stacking...identify the best cocktail of genes when the relationship between genotype and phenotype is best described...
  15. Adenoviral Vector Production and Troubleshooting

    Type
    Blog Post
    Published
    June 14, 2018, 11:44 a.m.
    ... and then stained 10 days later. Plaques are counted and titer is calculated in terms of plaque forming...medicine (2017).   1st Gen AdVs are stripped of regulatory genes E1 and E3. Without these genes, AdVs cannot...8.2 kb, and in vivo transgene expression ceases relatively quickly due to immune response against AdV. Importantly...low titer rAdV-S, and can be stored at -80C for later use or used immediately for amplification.*Pro-Tip...not use CsCl are commercially available. Titer calculation (1 or 10 days) Physical titer (particle count...260nm corresponds to 1.1 x 1012 particles/mL. To calculate the particle number: OD260 reading x dilution ...
  16. Genome-wide Screening Using CRISPR

    Type
    Blog Post
    Published
    Aug. 18, 2015, 2:30 p.m.
    ...screening experiment is to generate and screen a population of mutant cells to identify genes involved in...experiments commonly use lentivirus to deliver a pooled population of gRNAs to Cas9 expressing cells. Pooled lentiviral...CRISPR libraries”) consist of a heterogeneous population of gRNA-containing lentiviral transfer vectors...the CRISPR library to generate a heterogeneous population of mutant cells, with each cell or set of cells...distribution is analyzed in the drug-resistant population compared to a non-treated control group. In this...maintaining the distribution of each gRNA within the population is key. Loss of representation due to enrichment... sufficient representation within your mutant population requires a massive amount of cells as starting...
  17. Mobile-CRISPRi: Bringing CRISPRi to Diverse Bacteria

    Type
    Blog Post
    Published
    April 4, 2019, 12:53 p.m.
    ...that grew on a selective plate versus the number that grew on a non-selective plate. Most bacteria tested... types of bacteria: lab-adapted, environmental isolated, and disease-associated. Mobile-CRISPRi: a modular...glmS gene in the recipient's genome. Antibiotic plates lacking DAP select against donor bacteria and for...including pathogenic strains and environmental isolates. For example, Peters and colleagues used Mobile-CRISPRi...aeruginosa) in addition to Vicrio casei, a bacteria isolated from cheese. Knockdown efficiency, as measured... 100-fold excess of wild-type bacteria and the relative frequency of each of the 40 library strains was...
  18. Fluorescent Tagging of Endogenous Genes with SapTrap

    Type
    Blog Post
    Published
    Oct. 12, 2017, 2:26 p.m.
    ...individually generate gRNAs and homology arm repair templates containing the tag for each insertion. Also, it..., as well as the 5’ and 3’ homology arm repair template (Fig. 1, Step 1). There is no need for PCR or ...the second site accepts the homology arm repair template. SapTrap includes a prebuilt donor plasmid library...be used to generate functionally unique repair templates. A final ligation reaction correctly assembles...genetic locus, the toolkit also offers repair templates for tagging proteins in a tissue specific manner...of auxin to the culture medium. Any number of regulatory sequences, including protein enhancers and repressors...repressors, can be included in the repair template for inducible alteration of protein expression levels...
  19. Plasmids 101: Knockout/Knock-In Plasmids

    Type
    Blog Post
    Published
    Dec. 1, 2016, 3:30 p.m.
    ...homologous recombination using a repair template. These templates can include loxP sites to create conditional...recombination. The concept is simple: deliver a template with a modified version of the targeted sequence...sequence to the cell which will recombine the template with the endogenous gene. Here, we'll describe the ... one of the homology arms. When we select cells later, we will first perform a positive selection for ...selection for the negative selection marker - this latter step will kill off many of the cells that have ...knockout targeting vector designed to insert and later remove a resistance gene. In this construct, the...
  20. Hot Plasmids and Viral Preps - May 2021

    Type
    Blog Post
    Published
    May 18, 2021, 1:15 p.m.
    ...VP1, which self-assembles into a compartment encapsulating the protein of interest (Figure 3).   ...D-glucaric acid biosynthesis. This MPyV system encapsulated a rate-limiting enzyme in this pathway (myo-... of the protein compartment. Yeast with this encapsulated enzyme produced 20% more D-glucaric acid, suggesting...system can improve metabolic pathway yields by encapsulating a single enzyme. Compared with previous research...captures rare clones that represent 0.001% of the population.  Because indel generation by Cas9 can occur ...steady rate, scientists found a way to use the accumulation of indels to measure time. These plasmids with...ready-to-use viral preps with more on the way. S5E2 regulatory element containing vectors developed in the Jordane...
Showing: 201 - 220 of 763 results