We narrowed to 1,880 results for: ELL
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TypeBlog Post...dynamic samples Ex: monolayers of live cells with fluorescently labelled, motile structures These samples are...high light doses to the cells. Thin static samples Ex: Fixed monolayers of cells or thin (<15 μm) tissue...Biological Imaging and a Lecturer on Molecular and Cellular Biology at Harvard University. No matter whether... 10s of nanometers. Thick dynamic samples Ex: 3D cell cultures, small model embryos >15 μm Thsee are some...shouldn’t be afraid to seek out expertise from a well-established microscopist at your institution when...Biological Imaging and a Lecturer on Molecular and Cellular Biology at Harvard University. Additional ...similar information References 1. Lichtman JW, Conchello JA. Fluorescence microscopy. Nature methods 2,...
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Plasmids 101: Mammalian Vectors
TypeBlog Post...transfected cells may be considered an entirely new cell line from that of the original parental cells. Positive...cultured mammalian cells. Of course, these mammalian vectors must be compatible with the cell type they are...bacterial cells); however, the techniques and reagents vary. Plasmid transfection into mammalian cells is fairly...expression levels in the cells. Ideally, the chosen reporter is unique to the cell, is expressed from the...components expressed in trans within the cell for effective replication. Cell lines expressing the Epstein–Barr...mammalian cells To achieve stable transfection, there should be a selective pressure to force cells to incorporate...(basically growing cells in various concentrations of the selection reagent). Cells should die within ... -
The Breast Cancer Microenvironment: A Tumor’s Backstage Team
TypeBlog Post...and spread of cancer cells. Besides these stromal cell modifications, stromal cells are also constantly...how cancer cells influence microenvironments and vice versa, let’s take a look at cancer cell metabolism...inflammation, a noteworthy cell type in the tumor microenvironment is the immune cells. The contradiction is...injecting breast cancer cells into mice, exosomes expressed specific integrins (cell-adhesion proteins) targeting... be transferred to other cells, inducing epigenetic changes in targeted cells. In this case, exosomes ...Friendly” microenvironment cells Not all is bad news – we also have “friendly” cells in microenvironments! ...Take myoepithelial cells for instance. They retard tumor formation by inhibiting cell growth, invasion,... -
GCE4All: Making Genetic Code Expansion Accessible
TypeBlog Post...published, followed soon by GCE done in mammalian cells (Shandell et al., 2021). How it works If you’re interested...with) the cells’ own natural translation machinery; these are often incorporated into the cells via plasmid...so complicated? Well, while the techniques are straightforward, the systems – the cells growing and producing...is usually added to the media for uptake by the cells. Second, you’ll need tRNAs and tRNA synthetases ...biosynthetic pathway for the ncAA integrated into the cell’s genome, instead of incorporation via plasmid or...Theoretically, if you put all these together, the cell will produce a protein with a site specifically ...component of the experiment system (including media, cell type, and growth temperature) may need to be individually... -
GPCRs: How Do They Work and How Do We Study Them?
TypeBlog Post...article was written by Alyssa Cecchetelli and Andrew Hempstead. What do smell, taste and sight have in common...with heterotrimeric G proteins on the intracellular side of the cell membrane. Heterotrimeric G proteins...induce or inhibit intracellular signaling cascades as a response to the extracellular stimuli. Ligand dissociation...Peroxidase-Catalyzed Proximity Labeling. Cell 169:338-349.e11 . https://doi.org/10.1016/j.cell.2017.03.028 Roth BL (2016...to the seven alpha helices that transverse the cellular membrane. The receptor recognizes the appropriate...signaling is initiated when a ligand binds to the extracellular surface of the GPCR. This results in a conformational...small molecules to elicit a response in a certain cell type. Chemogenetics is similar to optogenetics but... -
Luminescent Imaging with Nano-lanterns
TypeBlog Post...have become indispensable tools for molecular and cell biologists over the last two decades, but their ...light. Long-term light exposure can also lead to cellular phototoxicity, and experimental success can be...quantum yield, and when transiently expressed in cells, generates much less signal than comparable fluorescent...produce photons. The original nano-lantern emitted yellow-green light and exhibited 3-5 fold increased brightness...three luminescent proteins can be used together in cells. As Nano-lanterns are not subject to photobleaching...phototoxicity, they successfully imaged multiple subcellular compartments over several minutes using Nano-...concentrations of the compound can be added to the media. Cellular esterase then converts diacetyl coelenterazine-h... -
Transferable Skills Guide: Time Management
TypeBlog Post...splitting my cells first. Time management through planning I probably wouldn’t have fallen into my cell splitting...for Scientists. Back when I used to do mammalian cell culture, I would often respond to friends asking...there in a few minutes, I just need to split some cells.” Inevitably, this task would take longer than I...since my days as an undergrad working with cancer cell lines. As I started planning out my own experiments.... In my anecdote above, I prioritized splitting cells over meeting up with friends, but didn’t realize...mean in terms of the utility of your tasks. In my cell splitting anecdote, I probably could have grabbed...with friends and come back to the lab to split my cells later. Eating with friends has a somewhat immediate... -
Evolution of Lab Techniques
TypeBlog Post...Neuroscience at Harvard University. Just as computers, cell phones, and cars become more technologically advanced...blotting, restriction mapping, and sequencing gels, as well as their modern equivalents and see what we can ...gene mutation is the genetic test used for sickle cell anemia (2). Southern blotting, in conjunction with... of the mutated β globin gene that causes sickle cell anemia. The mutation happens to destroy a sequence...conducted on a sample from an individual without sickle cell anemia, two DNA fragments are observed because the... site where MstII cuts. In a patient with sickle cell anemia the enzyme does not cut the DNA so only one...strand (8). Adding a small amount of a single radiolabelled ddNTP to a synthesis reaction along with all... -
Antibodies 101: Introduction to Antibodies
TypeBlog Post...on or in these cells: antibodies can bind to proteins on the cell surface, or the cell membrane can be...same cell simultaneously as well as compare between samples. Learn more about flow cytometry. Cell and ...antibodies are produced by B cells. They bind to proteins on the surface of extracellular pathogens such as parasites...fusing B cells that have been extracted from animals injected with protein antigen to myeloma cells. The ... measurement of protein expression in cell lysates, whole cells, or tissue samples. Many experiments that...shows that a similar concentration of cell lysate was added to each well. Image from Sun et al., 2010. ...heterogeneous mixture - for example, cell lysate or media from cultured cells. ELISA can be used to quantitatively... -
Getting the Most from Your Lentiviral Transduction
TypeBlog Post...quiescent cells do not take up nucleic acid or express transgenes as well as actively dividing cells resulting...therefore titers obtained in one cell type may not translate well to other cell types. To overcome this issue...Love your cells and they'll love you back A successful lentiviral infection begins with your cells, both ...both your packaging cells and your target cells. Poor tissue culture practices can lead to low titers and... promote cell growth. Overgrown cultures stimulate quiescence, the resting phase of the cell cycle; quiescent...reaching 108 cells per ml before the media becomes cloudy. Mycoplasma compete with host cells for nutrients... your producer cells with fresh medium. Daily medium exchanges help alleviate cellular stresses associated... -
Hot Plasmids - March 2020 - base editors, GEVI, MoClo, and optogenetics
TypeBlog Post...This novel tool is practical in cell and organ culture, as well as cell lineage studies. Eisenhoffer and...CreLite for cell tracing using the transgenic zebrafish model, ubi:zebrabow. In this system, cells express...such as the brain, eye, muscle and epithelial cells, as well as in different stages of development, ensuring...fast-splicing split intein and co-infected into the cell. Intein splitting removes any exogenous sequences...split into two plasmids and co-transfected into cells for reconstitution. Image from Levy et al., 2020...red-light inducible optogenetic tool for precision in cell lineage tracing Article contributed by Erin Sanders...fluorescent proteins controlled by Cre recombination. Each cell can have multiple copies of the transgene that recombine... -
CRISPRainbow and Genome Visualization
TypeBlog Post...Genomic Loci in Living Human Cells by an Optimized CRISPR/Cas System.” Cell 155 (2013): 1379-1491. Pubmed...of 6 chromosome-specific loci in the U20S cancer cell line./ Each color represents a gRNA targeting a ...localization and movement of this locus in live cells! This technique was developed in the lab of Addgene...et al. to track telomere dynamics throughout the cell cycle. To optimize the signal to noise ratio of ... Green PP7-PP7 Red boxB-boxB Cyan MS2-PP7 Yellow PP7-boxB Magenta boxB-MS2 White boxB-MS2-PP7...different hairpins will produce a secondary color cyan, yellow, or magenta, depending on the hairpin combination...gRNAs with two different hairpin sequences produce yellow, cyan, or magenta light. A gRNA with all 3 distinct... -
Pairing CombiGEM and CRISPR for Combinatorial Genetic Screening
TypeBlog 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 ... build and constantly improve gRNA libraries, excellent resources with effective gRNAs are publicly available...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... -
A Needle in a Base-Stack: Cas9 Structural Biology
TypeBlog Post...Guide RNA and Target DNA. Cell, 156(5), 935–949. https://doi.org/10.1016/j.cell.2014.02.001 Osuka, S., Isomura... includes the HNH and RuvC catalytic domains, as well as the CTD (also known as the PI), while REC includes...colored as in Figure 1. HNH, red; RuvC, orange; CTD, yellow; REC lobe, light blue; bridge helix, purple. ... Fun Fact! Even though the Cas9:RNA complex is well described in the closed conformation, recent electron...structural disorder. HNH, red; RuvC, orange; CTD, yellow; REC lobe, light blue; bridge helix, purple; sgRNA...efficiency and are important for robust activity in cells (Jiang & Doudna, 2017). Within an interior cavity...from that structure. HNH, red; RuvC, orange; CTD, yellow; REC lobe, light blue; bridge helix, purple; sgRNA... -
New Acoustic Reporter Genes: Ultrasound Imaging of Gene Expression
TypeBlog Post...producing cells. After FACS, return the cells to doxycycline-free media and expand the cells. Use a subset...CMV-gvpNJKFGWV plasmid into 70%-confluent well of HEK cells in a 6-well dish and change the media every day ...white inclusions in cells with GVs via phase contrast microscopy, GVs visible in cells via TEM, and purified... heterogeneity required single cell screening to isolate a clonal cell line capable of producing ultrasound...able to express Anabaena GVs in mammalian cells without the shell stiffening protein GvpC, which allowed ...expression homogeneity, as the cells could be batch-sorted to isolate a polyclonal cell line with strong gas vesicle...transient transfection in rtTA+ cell lines (such as HEK293-TETOn cells), or they can also be integrated... -
Generating Mouse Models Using CRISPR/Cas9
TypeBlog Post... into a mouse embryonic stem cell (ESC) line, enrich and select for cells that had successfully incorporated... when it gets exciting – the cell sends out an “SOS” signal and cellular repair mechanisms rush in to ...Cas-Mediated Genome Engineering. Cell 154:1370–1379 . https://doi.org/10.1016/j.cell.2013.08.022 Yoon Y, Wang ...Cas-Mediated Genome Engineering. Cell 153:910–918 . https://doi.org/10.1016/j.cell.2013.04.025 Zhang X, Liang...develop into chimeric mice (with a fraction of the cells in the adult mice derived from the engineered ESCs...file. Then I saw it, the chromatogram showing the telltale signs of a mutation introduced by CRISPR. The ...immune system in bacteria and archaea. As you know well if you’ve been following the Addgene blog, it has... -
Simple CRISPR-based Epigenetic Editing: dCas9-directed DNA Demethylation
TypeBlog Post...its oxidized derivatives. Cell 152, 5 P1146-1159. https://doi.org/10.1016/j.cell.2013.02.004. Xu X, Tao...targeted DNA demethylation. Cell Discov 2, 16009. https://doi.org/10.1038/celldisc.2016.9. ...interacting with transcription machinery. Well, I’ve got some good news: complete DNA demethylation...enzymatic activity cause demethylation? Dividing cells depend on DNA methyltransferase 1 (DNMT1) to copy...methylate sites blocked by dCas9. Within a few rounds of cell division, the original methylated strand is diluted...restrictions, anything within 5 base pairs should work well, and up to 10 base pairs away (especially 3’ of ...dCas9 expression and pLM-CMV-R-Cre. Selection for cells stably and highly expressing these constructs can... -
Plasmid-based Recombinant Monoclonal Antibodies: What They Are and Why You Should Be Excited About Them
TypeBlog Post... be introduced into host cells, such as bacterial, yeast, or mammalian cells, for antibody production ...Nanobodies and recombinant binders in cell biology. Journal of Cell Biology 209:633–644 . https://doi.org...animals and bleed dates and even clonal hybridoma cell lines can produce more than one mAb (Bradbury et...plasmid or from an integrated sequence in a stable cell line. The genes encode the heavy chain and light...antibody protein binds an antigen. Image from Fvasconcellos. How are Recombinant Antibodies Made...to create antibodies to targets that may not work well in animals because of similarities to host proteins...light chain recombinant monoclonal antibodies as well as other forms of antibody-based (e.g., nanobodies... -
Cpf1 Update: Comparison to Cas9 and NgAgo
TypeBlog Post...CRISPR-Cas System. Cell. 2015 Sep 23. pii: S0092-8674(15)01200-3. doi: 10.1016/j.cell.2015.09.038. PubMed...characterized two Cpf1 nucleases, distant cousins of well-known Cas9. Cpf1 cleaves DNA in a staggered pattern...editing than Cas9, confirming that this protein is well suited for genome editing. Find Cpf1 Plasmids at...RNA-guided endonuclease of a class 2 CRISPR-Cas system." Cell (2015). PubMed PMID: 26422227. Potential ...particularly helpful for targeting non-dividing cells, which are difficult to modify through homology-... smaller than SpCas9. These nucleases should fit well into AAV vectors, especially given that Cpf1 gRNAs... Cpf1 orthologs known to be active in mammalian cells, LbCpf1 and AsCpf1. In both reports, on target editing... -
Viral Vectors 101: Systemic Capsids
TypeBlog Post... your cell type of interest, while miRNA target sites can be used to prevent expression in cell types ... promoter/enhancer strengths in the cell type of interest as well as the type of transgene delivered: ...endothelial cells in rodent CNS AAV-PHP.V1 shows higher transduction in CNS endothelial cells (60%) and ...endothelial cells in the retina and spinal cord (Krolak et al., 2022). Systemic capsids for broad cell type ...delivery across species. Cell, 184(19), 4919-4938.e22. https://doi.org/10.1016/j.cell.2021.08.028 Vormstein-Schneider...system (PNS). (Capsids, if you recall, are the outer shell of an AAV vector, which determine the vector’s tropism... discuss how systemic capsids are engineered, as well as highlight some considerations for their use. ...