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  1. What's New in CRISPR - March 2020

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    Blog Post
    ...for studying the bacterial cell cycle, asymmetric cell division, and cellular differentiation, but it takes...crescentus Multiplexed gRNA for human pluripotent stem cells CRISPR-based DNA demethylation Optogenetic repressors...Figure 1: Serial dilutions of CRISPRi in Caulobacter cells for ctrA gene expression using various dCas9. Image...lab repressed ctrA, a gene encoding an essential cell cycle regulator. The lab expressed both dCas9 and...piggyBac transposon system for human pluripotent stem cells Lindy Barrett’s lab developed new fluorescently ... of multiplexed gRNAs in human pluripotent stem cells. Previously, CRISPRi or CRISPRa depended on continued...KRAB and dCas9-VPR for quantifying and tracking cells that express both the dCas9 construct and the fluorescently-labeled...
  2. CRISPR History and Development for Genome Engineering

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    ...genomic loci in living human cells by an optimized CRISPR/Cas system. Cell . 155(7):1479-91. PMID: 24360272... for Mapping Multiprotein Complexes in Human Cells. Cell Rep . 13(3):621-33. PMID: 26456817 Fu Y, Sander...described CRISPR-based genome editing in mammalian cell culture. Five years later, PubMed lists more than...multiple loci can be easily expressed in the same cell or organism. The ability to precisely target CRISPR...genome edits or double-strand breaks. In mammalian cells, Cas13-ADAR2 does not require a specific flanking...proteins can be used to image genomic loci in live cells. RNA targeting : Cas13 enzymes target RNA rather...non-specific cleavage does not occur in mammalian cells. Purify : Epitope-tagged dCas9 can also be used ...
  3. Fluorescent Proteins 101: Luciferase

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    Blog Post
    ...luciferase assays require cell lysis as the most efficient means to disrupt the cell membrane and deliver ...miRNAs for effectiveness. Analyze Cell Signaling Pathways Known cellular signaling pathways can be investigated...luciferase as a genetic reporter in plant and mammalian cells. Luciferase assays have since become a gold standard... serves as an indicator of transcription within cells, where detection of the reporter protein or its ... into the desired mammalian, plant or bacterial cells. Expression of luciferase as the reporter gene is...can permit measurements of luminescence from live cells. Monitor miRNA knockdown Expression of luciferase...codon, which is then transfected into the desired cells. A hybrid mRNA transcript containing luciferase ...
  4. Stabilized Bacterial Promoters: Constant Gene Expression at any Copy Number

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    Blog Post
    ... engineer cells for specific purposes. Unfortunately, plasmid copy numbers vary within cell populations...problems. Rapidly dividing cells initiate genome replication more than once per cell division and thus, genes.... When cells are dividing rapidly, multiple rounds of replication are initiated before the cell has divided...growth rate can all impact plasmid copy number in a cell. One can attempt to eliminate fluctuations due ... pSC101 with copy numbers ranging from 3-100 per cell, a stabilized promoter buffered against the effects... to stationary phase, the number of plasmids per cell increases 4-5 fold (for pUC plasmids) or ~2 fold...fold (for p15a, R6K, and ColE2 plasmids) as cell division slows (Kittleson et al., 2011). Segall-Shapiro...
  5. Adeno Associated Virus (AAV) for Cell and Gene Therapy

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    Blog Post
    ... do so, their T-cells were grown in vitro, their mutations corrected, and the T-cells were transferred...functioning T cell repertoire (1). In this example, it was possible to transduce the T-cells outside the...a wide range of cell types including but not limited to muscle, liver, and brain cells. There are a multitude...chain (c) and is characterized by a lack of immune cell development and function. To date, gene therapy ...that can deliver gene therapies directly to the cells that need them. Adeno-associated virus (AAV) – based...delivery of nucleic acid cargo (DNA or RNA) to target cells has been challenging. A variety of vector delivery...expression over many years in postmitotic, long-lived cell types. AAVs in the clinic Thus far, AAV vectors...
  6. Hot Plasmids May 2018 - Optogenetics, Decaffeination, Biosensors, and Fluorescent Protein Tools

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    Blog Post
    ...illumination of neighboring cells evokes action potentials (APs) in patched cells expressing wild type CoChR...techniques for live-cell imaging of the dynamic changes in biochemical activity within the cell. Their Fluorescence...28646204. soCoChR: A novel opsin that enables single-cell optogenetics Article contributed by Meghan Rego ...wild type CoChR, soCoChR localizes primarily to the cell body with very little signal detected along the ...CoChR, these APs are absent in soCoChR-expressing cells. Finally, using synaptic receptor blockers to distinguish...precise mapping of neuronal networks at the single-cell level. Various soCoChR plasmids described in this...strain to assay for functional decaffeination in cells. The ΔguaB E. coli are missing an essential enzyme...
  7. Split-BioID: An Improved Method for Studying Protein-Protein Interactions

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    Blog Post
    ... expressed in cells via plasmids or by the creation of stable cell lines and these cells are then grown... complex. Not performed in a native cell context. For AP-MS, cells are lysed before the bait protein is...and interacting proteins in mammalian cells. The Journal of cell biology. PubMed PMID: 22412018. PubMed...against PPIs that aren't stable outside the native cell context. The Split-BioID method Enter Split-BioID...tagging of proteins in both BioID or Split-BioID, cells are lysed, protein extracted, and labeled protein...proteins that interact with the bait in a native cell contact. Other PPI methods may require protein interactions...interactions to remain stable (or to be stabilized) during cell lysis and lysate fractionation. Important considerations...
  8. Plasmids 101: Optimizing Plasmid Yields

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    Blog Post
    ...large amounts of carbohydrates that can inhibit the cell lysis process. To ensure that lysis is complete,...strains adapted for protein purification use the cell’s resources to produce high levels of protein, not...difference? In the simplest of terms, more volume = more cells = more plasmid. Plasmids can vary in copy number...of plasmid copies supported within each bacterial cell in your culture. Copy number is partially specified...richer media or adding supplements can improve your cell density, leading to an improved plasmid DNA yield... supplements to the media You can achieve higher cell density using a nutrient-rich broth such as Terrific...glucose (in moderation) may also serve to increase cell density and plasmid yield. Start with a single, ...
  9. Tetracycline Inducible Expression

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    Collection
    ...systems were tested for functionality in mammalian cells. The lac system with the inducer isopropylthio-β-galactoside... and Bujard tested the tet system in a mammalian cell system (HeLa) and found that the tet system was ... interest rtTA or TetR expression plasmid Stable cell lines can be made that continuously express a system...derivatives can be viewed in Krueger et al, 2004. Some cell culture sera may contain tetracycline or its derivatives...of gene expression at a single copy in mammalian cells; Expresses firefly luciferase hairpin and GFP under...vector lentiviral Gateway RNAi system for conditional cell line generation; contains expression cassette for...CMV promoter, and Blasticidin; can be used to make cell lines Tet-On Advanced; Plasmid 26730 has hygro resistance...
  10. Neurodegeneration Research Collection

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    Collection
    ...protein-protein interactions and nerve cell function within the cell. Parkinson's Disease Parkinson’s disease...inducible vector . Harley et al. Cell Rep. 2023 Dec 26. Induce CNS cells with concomitant expression of ...that causes the progressive degeneration of nerve cells in the brain. Symptoms include changes in behavior...FRET-based reporter to study tau seeding in mammalian cells. Lathuiliere et al. Mol Neurodegener. 2023 Aug 8...system, peripheral nervous system, vesicular brain cells and more. New and Noteworthy: AAV.rTH.PI.Cre.SV40...and cortical neuron differentiation. Held et al. Cell Rep. 2023 Aug 30. Enhance differentiation to mesencephalic...neuronal identification in C. elegans. Yemini et al. Cell. 2021 Jan 7. Use a FRET-based method to monitor ...
  11. The AAVantages of AAV in CRISPR Screens

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    Blog Post
    ...same: Deliver CRISPR library to cells of interest. Select for cells of interest (positive or negative...infect specific cell or tissue types. Using serotypes that have a known tropism for your cells of interest... a host cell’s genome. In this state, AAV cargo can be stably expressed in non-dividing cells for long...mice are involved. Ex vivo starts with transducing cells with the CRISPR library in vitro before transplanting...interest — for example, AAV8 for kidney cells — can help improve infection rates in your experiment. ...AAV vectors, enhancing their affinity for specific cell and tissue types. The combination of serotypes and...integration sites seem to only occur in the target cells or tissues. AAV also shows improved transduction...
  12. Viral Production at Addgene

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    Blog Post
    ... preparations are added to cells in culture. Three to five days later, cell cultures are inspected for...a new vial of early passage cells. Approximately two weeks post-thaw, cell culture supernatant is tested...section for images).     Figure 2: AAV Pro cells were transduced with either pAAV-Ef1a-mCherry-IRES-Cre... (55634-AAVrg) alone at 1.7E6 viral genomes (vg)/cell, pAAV-CAG-FLEX-rc [Jaws-KGC-GFP-ER2] (Addgene 84445...preparations ("-LV” catalog items) are produced in 293T cells using the 2nd generation psPAX2 and pMD2.G packaging...packaging system developed by the Trono lab. Cell culture medium (OptiPro SFM) containing lentivirus is first...modified from Wang et al., 2018). Briefly, 293T cells are transduced with serial dilutions of a lentiviral...
  13. CRISPR 101: Validating Your Genome Edit

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    Blog Post
    ...number of cells have been edited. For many experiments, the end goal is to generate a clonal cell line, so...designed your gRNA and introduced it into your target cells with Cas9. Hooray! Now it’s time to make sure your...blog post we’ll explain how to verify that your cells were appropriately edited for your desired mutation...important to know a few things about your target cells and the desired edits. First, you will need to know.... Validating knockout mutations When a knockout cell line is desired, any mutation that introduces a ...input is sequencing trace files of WT and edited cell lines. Then decomposition analysis is performed ...both an unedited population and your Cas9-targeted cells. Simply upload both trace files to the TIDE tool...
  14. Antibodies 101: Single Chain Fragment Variables (scFvs)

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    Blog Post
    ...scFvs and T cell receptors and are expressed on T cells to make CAR T cells. The extracellular scFv portion...Bispecific T-cell engagers (BiTE®s), bind CD3 on T cells and a tumor-specific antigen, it brings T cells to a ...scFv part of the receptor can activate T cells to kill cancer cells. scFv’s small size also allows for their...recognizes an antigen of interest while the intracellular T cell receptor portion of the CAR facilitates ... display libraries screen antibody genes from B cells of immunized animals, but it's possible to avoid...also allows for screening scFv generated from the B cell antibody genes from diseased or vaccinated humans...produce scFvs in mammalian, yeast, plant, and insect cells, they are most often expressed from a plasmid in...
  15. Your Top Requested Plasmid in 2016!

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    Blog Post
    ...both SpCas9 and your gRNA in a variety of mammalian cell types. Purpose  SpCas9 This plasmid expresses Streptococcus...the Zhang lab has tested in a variety of mammalian cell lines. Cas9, of course, is the key component of ... puromycin resistance gene enables selection of cells with the plasmid post transfection. The 2A "self...can be used to transfect a variety of mammalian cells and can be modified for viral trasduction (see the...resistance gene that made it less effective in certain cell lines. This point mutation has been corrected in... your gRNA of interest in a variety of mammalian cell lines. Alternative forms of this vector contain ...Common Ways to Deliver CRISPR Plasmids to Mammalian Cells Resources on the Addgene Website Visit our CRISPR...
  16. Important Considerations When Using AAVs

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    Blog Post
    ...transducing the cell type under study. Many AAVs will show significant expression in a variety of cell types, ...optogenetics as tools to investigate the roles of certain cell types in locomotion. We have relied heavily upon...deliver chemogenetic/optogenetic constructs into our cells of interest. Although they have a small packaging...of serotype (which determines which tissues and cells an AAV can infect) can influence an AAV’s value ... tissue? Location (2): Where in the tissue/which cell type? Location (3): Traveling from the original ...AAV5, AAV6, AAV9 Pancreas AAV8 Photoreceptor Cells AAV2, AAV5, AAV8 RPE (Retinal Pigment Epithelium...-vectors/aav/aav-guide. Where in the tissue/what cell type? In the CNS, for instance, there are marked...
  17. Illuminating Choices: A Guide to Selecting Fluorescent Dyes and Ligands

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    Blog Post
    ... is technically cell-permeable, its use in live cells can sometimes result in cellular toxicity due to... Dyes that can pass through cell membranes can prove useful for live-cell imaging. Experimental context...Additionally, cell permeability is a critical factor, as it influences the dye's ability to enter cells without...enabled the visualization of both organic tissues and cell cultures, opening biological interiors to many inquisitive...interfere with protein expression or function in live cells. Fluorophore properties: The specific properties...context of the experiment, such as the presence of cells or specific proteins, can influence the choice of...ligands is unaffected by additional protein from cells under certain conditions, which is an important ...
  18. Ras Pathway

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    Collection
    ...molecular switches that transmit signals within the cell. GTPases have an active (GTP) and inactive (GDP)...prominent roles in signaling pathways regulating cell migration, survival, adhesion, growth, and differentiation...Cancer Impact Ras is ubiquitously expressed in all cells and all tissues. Ras can activate a variety of ...pathways, which ultimately turn on genes involved in cell growth, differentiation and survival. Ras is essential...essential for regulating the growth of the cell, however when mutations occur in the Ras gene it can be... active form, constantly activating pathways for cell growth and potentially leading to cancer. Constitutively...E2F2 E2F3 E2F transcription factor ECT2 Epithelial cell transforming 2 EGFR Epidermal growth factor receptor...
  19. 15 Hot Plasmids from 2017

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    Blog Post
    ... of cell types in the nervous system. While certain cell types, such as principal excitatory cells and...neuronal cell types involved in neurodegenerative diseases, the Cole Lab selected promoters for cell types...with edited “pools” of cells, eliminating the time-consuming step of single-cell isolation. Agudelo et ...gene. Koo M, et al. Cell Systems. 2016. PubMed PMID: 28189581 Peters J, et al. Cell. 2016. PubMed PMID:...generation Deriving iPSCs (induced pluripotent stem cells) through the expression of transcription factors...the established model for reprogramming somatic cells. A common method for generating iPSCs to express...work are available at Addgene. Kim, et al. Stem Cell Reports. 2015. PubMed PMID: 25772473 Targeting...
  20. Fluorescent Protein Guide: Subcellular Localization

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    Collection
    ...between animal cells. They are important for holding cell structures together and reducing cell stress. There...give the cell its shape, organize cellular organelles, and are necessary for movement and cell division...example, houses the cell’s genetic material. The mitochondria produces the energy cells required for chemical... on cell cycle) Centrin-2 EGFP Erich Nigg 41151 pEGFP Cep170 C-term Centrioles (dependent on cell cycle...Fluorescent Protein Collection . Return to top Cell Junctions Cell junctions are responsible for forming connections... General Structures The cell contains a variety of organelles and subcellular structures each with their...its role in secreting proteins from the cell to the extracellular environment. Proteins are first translated...
  21. CRISPR Plasmids for Genomic Visualization

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    ...compatible with fluorescence microscopy in living cells. Alternatively, gRNAs can be fused to protein-interacting... multiple genomic loci, and compatible with live cell imaging. Compared to techniques like fluorescence... for detecting the chromatin dynamics in living cells. The fluorescent CRISPR system has been used for... loci, as well as chromosome painting in living cells. Visualizing a specific genomic locus requires recruitment...repetitive loci can be efficiently visualized in living cells using a single gRNA that has multiple targeted sequences...
  22. Google Forums Round Up: First Impressions of NgAgo

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    Blog Post
    ...degraded by the cellular machinery, leaving a small amount of active NgAgo/ssDNA complex in the cell. As proposed...results of Gao et al 2016 in a letter to Protein & Cell. Update (August 3rd, 2017) THE ORIGINAL NgAgo ARTICLE... guide, it cannot be produced from a plasmid in cells. Additionally, in vitro assembly of NgAgo/ssDNA ...dangerous, non-physiological temperature for mammalian cells and one which diminishes the endonuclease activity...guide. Therefore, researchers must co-transfect cells with 5’-P-ssDNA guides and an NgAgo expression plasmid.... Researchers can conveniently transfect/inject cells with in vitro preassembled Cas9/gRNA complexes or...lipofectamine-based method to deliver NgAgo ingredients into the cell, the same method used by Gao et al, 2016 (1). View...
  23. BeHeard Award 2018: Diseases of Glycosylation, Arginine Mutagenesis, & Neural Development

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    Blog Post
    ...the physiological and pathological roles of human cell glycans. Accordingly, she joined efforts with the...aspect of immunology, participating in events such as cell development, recognition and migration, the immune...plasmids to immortalize CDG patient-derived immune cell lines and use these lines to study how immune processes...McMurray is an Associate Professor in the Department of Cell and Developmental Biology at the University of Colorado...evidence of Arg-mutant protein rescue in living cells. The McMurray lab found that low concentrations ...multiple Arg-mutant proteins in living baker’s yeast cells, including Arg-mutant yeast homologs of human proteins...disease-linked Arg-mutant proteins both in yeast and human cells in order to determine the specific molecular features...
  24. Pairing CombiGEM and CRISPR for Combinatorial Genetic Screening

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    Blog Post
    ...genes essential for West-Nile-virus-induced cell death." Cell reports 12.4 (2015): 673-683. PubMed PMID:... (and multiple) genetic perturbations in single cells. Methods to scale up multiplexed CRISPR systems ...perturbations and applications in functional genomics, cell reprogramming, and beyond. For further details, ...CRISPR-mediated control of gene repression and activation." Cell 159.3 (2014): 647-661. PubMed PMID: 25307932. PubMed...Genes and Genotype-Specific Cancer Liabilities." Cell 163.6 (2015): 1515-1526. PubMed PMID: 26627737. ...Genome-wide recessive genetic screening in mammalian cells with a lentiviral CRISPR-guide RNA library." Nature...Genome-scale CRISPR-Cas9 knockout screening in human cells." Science 343.6166 (2014): 84-87. PubMed PMID: 24336571...
  25. Antibodies 101: Flow Cytometry Controls

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    Blog Post
    ...and beads that are unable to bind to them: like cells but with far more predictability. The beads create...The benefit of beads is that they do not require cells from your experiment, and they are non-specific....flow cytometer, you generally want your positive cells to read between 104 and 105 in order to have enough...the plot to see all of your positive and negative cells. This can be achieved by adjusting your voltage ...gating schematic to easily determine where your cells of interest are (B).   Using FMO controls In...markers or commonly used markers that define broader cell populations (e.g., CD4, CD8b, CD11b, CD19), are ...require an FMO. Markers that define more specific cell populations, often used in the later gates, are ...
  26. Visualizing Genomic Loci with CRISPR-Sirius

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    Blog Post
    ... to date for visualizing genomic loci in living cells. Previous iterations of genomic loci visualization...labeling system to visualize chromosomal loci in human cells (Ma et al., 2015). To do so, they fused a different...visualization of sites on different chromosomes in living cells, the system requires high-copy chromosome-specific... aptamer system to visualize the gRNA in living cells. Broccoli aptamers are nucleic acid sequences that...production needed to deliver CRISPR-Sirius into cells. They named this guide sgRNA-Sirius-8XMS2 which ... 46 loci gave a detectable signal in human U2OS cells. Based upon this, they chose an intergenic DNA region...copy number variation (CNV) analysis of the U2OS cells.   Figure 2: CRISPR-Sirius tricolor labeling...
  27. CUT&RUN: An Improved Method for Studying Protein-DNA Interactions

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    Blog Post
    ...when working with cell culture, because it is easy to harvest large quantities of cells. However, when working...numbers of cells or when a high degree of signal to noise is desired. It also provides an excellent additional... been widely applied in many model organisms and cell lines. Although ChIP-seq is a relatively simple ...typically requires a large amount of input material, cells or tissue, to produce a strong enough signal over...protein of interest. First, nuclei from tissue or cell culture are isolated using lectin-coated magnetic...the usage of a strong detergent to permeabilize cells rather than to rely on nuclei extraction. They report...technique, specifically in terms of initial steps of cell or tissue preparation.   All in all, CUT&RUN offers...
  28. Plasmids 101: What is a plasmid?

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    Blog Post
    ... small circular piece of DNA found in bacterial cells, and someone new to plasmids may need some extra...and designed to introduce foreign DNA into another cell. Minimally, lab-created plasmids have an origin ...the ability of plasmids to self-replicate within a cell make them attractive tools for the life scientist...component for expression vectors: determines which cell types the gene is expressed in and amount of recombinant...plasmids also have selectable markers for use in other cell types. Primer Binding Site A short single-stranded...newly inserted gene is transformed into bacterial cells and selectively grown on antibiotic plates.  Importantly...plasmids to manipulate gene expression in target cells. Characteristics such as flexibility, versatility...
  29. Zebrafish as a Model for Behavior: Swimming into the Optogenetic Spotlight

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    Blog Post
    ... light sensitive proteins (opsins) to manipulate cell activity, enables researchers to silence or incite...channels that allow charged particles to cross the cell membrane when exposed to light. Neuronal firing ...channel LiGluR both cause ion movement that results in cell depolarization. They therefore function as a neuron...in negative chloride ions which hyperpolarize the cell. It therefore functions as a neuron “off switch....They found that photostimulating the Kolmer-Agduhr cells was sufficient to trigger the symmetrical tail movement...forward swimming. Furthermore, only Kolmer-Agduhr cells on one side of the body required photostimulation...symmetrical response.  The function of Kolmer-Agduhr cells had previously been a mystery, but through the control...
  30. A Scientist's Guide to Ebola

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    Blog Post
    ... infected cells to go undetected by the immune system in a novel way, by shielding host cell surface proteins... itself to escape vesicles within host cells and turn the cell into a veritable virus factory.  Their ... sets off.  The virus works its way into immune cells in ways that aren’t fully understood. Much of the... viral attachment and fusion. Once inside a host cell, new evidence in PLoS Pathogens shows that the Ebola...
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