...Organization has declared a global health emergency and called for the fast-tracked development of diagnostics...was a new class of programmable riboregulators, called toehold switches, which allow for the rational ...outbreak was reported, and we felt that, given the critical need for low-cost, field-based diagnostics, our...Our motivation was underscored by the potential scale of the emerging outbreak, as many as 2.2 billion...timeline to develop our paper-based platform into clinically relevant diagnostics for the Zika virus was daunting...ability to complete the project on such a short timescale. Our article ultimately reported the development...that has transformed the assay’s capabilities. Specifically this includes primer directed isothermal RNA...

... many biological research situations, the relevant volume is that of the cell. For the physical behaviors...major applications of FPs is to visualize the localization, dynamics, and behavior of a POI. As an investigator...monomeric FPs are not actually monomeric, at least in practical terms. The propensity of a particular type of ...fusion protein, as in a FRET biosensor, then the local concentration of FPs around that fusion protein ...consequences can be dramatic. For a membrane POI localized to the endoplasmic reticulum, the normally spiderweb-like...structures are large (microns), bright, non-physiological, and difficult to ignore [1, 2]. 2. Fusion to...fusion proteins that form as a result will often localize incorrectly and may function improperly. 3. Incorporation...

... the brain. A more locally defined set of neurons can then be targeted with optical stimuli. The restricted...viral vectors (AAV), neuroscientists can combine classical genetic tools with the manipulation of specific...of these discussions as a publicly accessible practical guide which was recently published in Frontiers...of molecular tools and sensors Combinations of classical genetic tools, for example Cre/loxP or Flp/FRT...transgene expression by restricting expression to genetically defined cell types. Specific transgene expression...result in opsin expression in their cell bodies. Optical stimulation in a different brain area can then ... more versatile. To complement the wealth of genetically encoded tools available, researchers are also...

... In vitro, ligases (notably T4 DNA ligase) are critical reagents for many molecular biology protocols,... smaller pyrimidine:pyrimidine mismatches are typically worse ligation substrates than pyrimidine:purine...design and reaction condition optimization, will be critical for success. Online tools are available to help... the Thermostable Ligase Reaction Temperature Calculator can be used to estimate an appropriate incubation... structure, reaction mechanism, and function." Chemical reviews 106.2 (2006): 687-699. PubMed PMID: 16464020... ligases: progress and prospects." Journal of Biological Chemistry 284.26 (2009): 17365-17369. PubMed ...reaction-capillary electrophoresis assay." Journal of clinical microbiology 45.6 (2007): 1927-1935. PubMed PMID...

...interaction with limited biological materials. Problems with Chip-seq ChIP-seq typically requires a large amount...activity of a Protein A fused micrococcal nuclease (MNase) to specifically isolate DNA that is bound by...material for a ChIP-seq experiment can be a major technical hurdle.   ChIP-seq requires  cross-linking during...development using the Drosophila wing as a model. A typical ChIP-Seq experiment requires around 1,000 wings...addition of Protein A MNase. Once MNase has been localized to target sites, the nuclease is briefly activated...targeted digestion is controlled by the addition of calcium, which MNase requires for its nuclease activity...and simplification of the original technique, specifically in terms of initial steps of cell or tissue ...

...screened for toxicity against local insect pests. By developing biological agents such as insecticidal ...get tested for their potential agricultural and medical use. Find More Optogenetic Tools Like pDawn  Making... improving expression of nutritionally and therapeutically significant proteins. In this project she aims...insecticidal proteins, the use of chemical pesticides may be avoided or decreased. Biosensors for herbicide detection...one of the reaction’s metabolites. One useful genetically encoded H2O2 probe is pQE-30-HyPer3 (2) which...working in a wide range of research fields and geographical locations. We are excited to see how all of ...et al. “Endophytes as sources of antibiotic” Biochemical Pharmacology 2017 Jun 15;134:1-17. PubMed PMID...

... well as neural development. Specifically, SHH is a morphogen, a chemical signal that diffuses down a ...exhibit abnormal segmentation during embryogenesis. Typically, regularly spaced denticles (bristles) outline...on the spindle of a spinning wheel but also a biological transposon system. Sleeping Beauty is a synthetic... cellular contraction You may think that a gene called "spaghetti squash" originated from the squash itself...contract depending on the context. Contraction is critical for processes such as cell movement/motility, ...or dead cells (Jiang and White-Cooper, 2003). Why call a gene required for spermatogenesis after a Sesame...mesoderm, is necessary to activate bagpipe which is localized to segmental clusters of the mesoderm. This subdivision...

...Immunoprecipitation Overview An immunoprecipitation reaction is typically carried out in one of two ways. Both methods utilize.... 2) An antibody immobilized on a bead binds specifically to the blue triangle protein but not the other... to the process of anchoring an antibody, often called the capture antibody, to agarose or magnetic beads... or magnetic beads with commercially available chemical agents. Directly conjugating the primary antibody...interactions To prepare for an IP, samples are typically lysed in a non-denaturing buffer containing non-ionic...sample to remove any proteins that may interact nonspecifically with the capture antibody or Protein A/G. To...interaction and/or the downstream application. Typically, if the target protein will be detected in a Western...

...Different antibodies bind different protein sequences called epitopes and scientists can use these to tag their...lab used an alternative strategy to develop a genetically encoded antibody based probe that detects the... epitope in diverse cellular environments. They called this probe the HA frankenbody (Zhao et al., 2019...targets, the scientists fused them to sequences called complementarity determining regions (CDRs, or loops...concept experiment the Stasevich lab observed colocalization of GFP tagged HA frankenbody with an mCherry...meaning that scientists can track the movement and localization of single HA-tagged molecules over time.  The... Inbar, D., Hochman, J., & Givol, D. (1972). Localization of antibody-combining sites within the variable...

...order in which specific chemical inputs are received by a cell. These so-called recombinase-based state...light and chemicals respectively. Didem Goz Aytruk from Connie Cepko’s Lab at Harvard Medical School describes...although fluorescent proteins are incredibly useful, chemical fluorophores can still be used in a wide variety...variety of experiments. Read more to find chemical fluorophores for your next experiment. Nucleic acid based...report upon and/or engineer “temporally ordered biochemical events” such as those that occur during development...to pH changes without the need for ATP or other chemical fuel sources.” In her work, Dr. Polka made R-body...repression of different genes in a single cell, and localization of a fluorescent signal to your target gene....

...by fluorescence photoactivation localization microscopy." Biophysical journal 91.11 (2006): 4258-4272....Berlin, Shai, et al. "Photoactivatable genetically encoded calcium indicators for targeted neuronal imaging...tag cellular proteins and investigate protein localization, interaction, and expression. However, one caveat...oligomerize, disrupting cellular function and localization, or leading to protein aggregation. Another ...important applications for PA-FPs involve enhancing optical live imaging of proteins, organelles, and cells...proteins, scientists can track single protein localization, turnover, and trafficking, as well as organelle...new imaging methods, including photoactivation-localization microscopy (PALM, also FPALM) (11). For PALM...

...run it? And, most importantly, what are the methodological and experimental limitations and considerations...numerous scientists at NIDA and some of the practicalities and considerations you may not find in the ...stimulate 2) Fabrication and implantation of the optical fiber into the region of interest 3) Behavioral...region and cell type of interest is obviously of critical importance to any optogenetic experiment. There...pioneered the development of optogenetics, has genetically manipulated a number of the opsin genes to alter...your opsin  The standard opsin delivery method is local injection of an adeno-associated viral (AAV) construct... or more mice and the injections must be near identical for all of these surgeries. Identify coordinates...

...MSDS for a lab chemical of choice. Now, I can’t guarantee every reagent in your chemical closet is in this...tried to find an app that could help me with calculations. This is how I came across the Gibco Cell Culture...culture and include a counter, lab timer, dilution calculator, and a couple of other nice features. This app...sequence for your enzyme of interest. Lastly, the Tm calculator helps you set up an optimal PCR depending on ...enzyme sequence resource is universally useful. 4. Chemical Safety Data Sheets by ThatsMyStapler Safety always...experiments. Hence, I’m including this MSDS app. The Chemical Safety Data Sheets app has a search function that... if you get quizzed randomly about a hazardous chemical and can’t find your lab’s MSDS book, this is a...

...Belarusian State University Series of Physiological, Biochemical and Molecular Biology Sciences. 9.1 (...genomic modification. This technique is frequently called allelic exchange. Here, a mutated allele introduced...: The initial plasmid integration step (the so-called “single crossover”) which results in a merodiploid...They hypothesized that genes that had evolved specifically for toxicity would allow stronger counter-selection...system is well-characterized and quite tight (Giacalone et al., 2006). The Chen lab demonstrated excellent...synthetic ribosome binding site (using the online calculator from the Salis group) (Espah Borujeni et al.,...from TP997). We validated these vectors, which we call “pTOX” in a broad group of Gram-negative Enterobacteriaceae...

...general (1). Science and politics? Science is an apolitical process for seeking knowledge. The process begins... again. No part of this process is inherently political so why is there a march in Washington, D.C., the...States government? Politics and science are intrinsically linked: governments exist in reality and science...as evidence of climate change, the safety of genetically modified organisms (GMOs), the absence of a link... it.  3) Linking scientists to one particular political party while alienating the other While scientists... yet research shows that thoughts on some non-political issues are split along party lines (18). Feeling...alternative. Inclusion of data informing policy specifically related to the following subjects: Climate ...

.... Lajoie, Marc J., et al. "Genomically recoded organisms expand biological functions." Science 342.6156...phosphorylation events on the activity of a given protein? Classical methods for studying protein phosphorylation A...plasmid. This includes 4 copies of a tRNA that specifically recognizes amber stop codons (TGA) to encode...effects on cell growth. The C321.ΔA strain was genomically recoded to eliminate all 321 amber stop codons...strain, TAG is an ‘open’ codon, which can be specifically recognized by the Sep-tRNA. 3. An expression...specific phosphoserine residue at this position. Practical tips for your experiments To generate as much ...containing Phos-Tag, a small molecule that binds specifically to phosphate moieties and promotes a robust ...

...methods including both chemical and physical methods in the lab. Chemicals like calcium phosphate and diethylaminoehtyl...competent through chemical manipulation in the lab. This is commonly done using calcium chloride which permeabilizes...also use electroporation, the application of an electrical charge to cells, to increase cell membrane permeability...contact. The donor bacterium contains a DNA sequence called the Fertility factor (F-factor). The F-factor is...easily cross the negatively charged cell membrane. Physical methods such as electroporation or microinjection...cells. Electroporation on the other hand uses electrical pulses to create transient pores in the cell ...

...almost always epigenetically silenced, but dysregulation of these systems can lead to local dsRNA production... DNA – right? RNA performs almost all of its biological functions in our cells in the single strand form...machinery of the host. This pathway has been clinically exploited for antiviral purposes similar to that...sequence. Once a compatible sequence is found (typically RNA that the RNAi is designed against), RISC can...target mRNA. These RNA tools have been used in clinical therapy to target pathogenic proteins, as well...and insecticides, an advancement over previous chemical versions with toxicity to many organisms. ...transcription of their circularized DNA. These dsRNAs are typically contained within the mitochondria, barring a loss...

...fluorescent genetically encoded voltage indicator Article contributed by Shreya Vedantam Genetically encoded... for its biotechnological applications including conversion of CO2 into water and electrical energy generation...can be reconstituted in vivo to form a protein identical in sequence to the unmodified enzyme. Each half...tested the base editors in vivo and achieved therapeutically relevant editing efficiencies in the mouse ... base editors at Addgene. Levy et al., Nature Biomedical Engineering, 2020. PubMed PMID: 31937940. Detection...single action potentials and further studies of optical neural circuit manipulations when combined with...fusion proteins separate, inactivating Cre. This is critical for reducing Cre toxicity in long-term experiments...

...detect mRNA from 10 bacteria of clinical significance and four clinically relevant host biomarkers. The ...microbiome with sequencing is vast, the ability to genetically alter microbiome members is limited and many ...at Columbia University developed a method for genetically altering gut microbiome members in their native...native habitat (Ronda et al., 2019). They called their method Metagenomic Alteration of Gut microbiome by... analyze gut microbiota and host biomarkers In clinical and diagnostic labs, deep sequencing and qPCR ...large number of microbiome samples. To enable large-scale, longitudinal studies of the gut microbiome, James...The lab validated their platform on clinical stool samples by comparison to qPCR and demonstrated that it...

...ability to specifically recognize and bind proteins. They’re used in a number of research and clinical applications...Instead, we're going to focus on what I'm going to call "alternative affinity reagents" - everything from... of the antibody’s ‘Y’. They are often used in clinical applications. Fab fragments can be created in ...other (Shahied, 2004). They are often used for clinical applications, including imaging.  Diabodies are... from a camelid antibody lacking a light chain, called a heavy chain antibody (Muyldermans S., 2013). ...Designed ankyrin repeat proteins, or DARPins, are genetically engineered small affinity proteins, around 14...proteins known as ankyrin repeat proteins. DARPins typically consist of 3-4 repeats, have high specificity ...

... the practical aspects of testing samples in the lab, but I really struggled with the large scale data... this summer position as I felt I needed more practical lab experience to later gain a full time position...really enjoyed some aspects of the work, such as physically carrying out experiments like PCR and running...least 3 months experience working in a developing tropical country. This is why I set up a placement working...first aid. This really allowed me to see the practicalities of working in the field with the most basic...Masters, because tuition fees had just gone up dramatically and, in England, you could not receive government...carry out my dissertation research in a lab in California. I felt then, and still feel now, that it is ...

...accurately calculate the protein concentration of any experimental wells in that range of optical densities.... When an ELISA kit is ordered, the wells are typically already coated with the antibody. Then, you add...process is the addition of a detection antibody (typically a monoclonal antibody) that also recognizes the... of enzyme present in the well and is used to calculate the amount of your protein of interest that is...is present. Using a Standard Curve To do that calculation, you’ll need to include a standard curve in your...concentrations of your protein of interest. The optical density (OD) - the measure of light absorbed by...samples can then be plotted along this line to calculate the protein concentration. Image from Jagarlamudi...

...et. al.). Physical versus functional titer Viral titers usually come in two flavors, physical or functional...the target cell’s genome. Physical titer The two most common assays for physical titer are direct p24 measurements...functional. Physical titers measure the amount of viral particles in a sample and are usually based on the...produced can actually infect cells. These assays typically involve infecting a target cell line with your...methods tend to be more accurate than measuring physical titer, there is a risk that they may underestimate...target gene. Developing the proper control line typically requires transducing with a limiting multiplicity...will the target cell type used. Therefore, it is critical that standard conditions be used when comparing...

...protein expression for experimental, biotechnological, and medical applications. Researches can visualize...of proteins including antibodies and pharmaceuticals, specifically interleukins. Yeast expression systems...tagging them with fluorescent proteins to study localization or purify proteins to study their structure,...these types of insect expression systems can be scaled up for production of large amounts of protein. ...time consuming as plant tissues themselves are biochemically complex. To circumvent these issues, scientists... taken advantage of the natural secretion of biochemicals and proteins through plant roots. Tagging recombinant...easily adapted to fermentation allowing for large-scale, stable production of proteins. In general yeast...

... curve to calculate its experimental value. Though it varies from assay to assay, typically the experimental...before running a western blot. Standard curves are critical for a number of popular scientific applications...curve by serially diluting a known control sample, called a standard. The ideal standard curve has at least...enzymatic assays are sigmoidal. Once the trendline is calculated, you can extrapolate the concentration of the...measurements and the trendline y = 0.6561x + 0.019 calculated. The concentration of an unknown sample is determined...standard curve scientists use graphing software to calculate the data’s coefficient of determination, R2. R2...running assays that rely on a standard curve, it is critical that the unknown sample’s concentration lies within...

...COVID-19 cases each week. Statistical Modeling Note -- If statistical modeling isn’t up your alley,... of Chemistry and Chemical Biology at Harvard University; and Howard Hughes Medical Institute Investigator...as expected, plasmid orders (left, blue) drop dramatically when there are many new COVID-19 cases being...order several plasmids at once, breaking the statistical independence assumption of the Poisson process...our distribution, resulting in the following hierarchical model: Because the U.S., Europe, and China ...multivariate Gauss-Hermite quadrature, since the analytical expression for the data likelihood contains an...His research uses applied machine learning and statistical methods for fundamental scientific discovery ...

... general public. Chemical Society in University College Dublin, Ireland The Chemical Society was founded...way up to professors. Oxford Biological Society, England The Biological Society based at the University...idea of the Freshers Fair and some of the great biological societies that Addgene has had the opportunity...at Freshers Fairs in the past year. Cambridge Biological Society, England Since 1996, Cambridge Biosoc...Biosoc’s goal has been to promote interest in the biological sciences amongst the student community at the...At Addgene, we’re incredibly glad to see these biological societies engaging with young scholars. We believe... to keep up the good work! What scientific or biological societies were you a part of in undergrad or ...

...graduate students and postdocs to think analytically and critically. Passion fuels the drive to continue ... Connie Cepko (Harvard Medical School) , and Dr. George Church (Harvard Medical School) for taking the...people (especially you!) care about. Have you critically evaluated your plan? Have you read the relevant...write a grant for this project, what would be your critical experiments and why? What techniques and skills...help move your project forward? Most projects typically require a diverse set of skills. It is important...direction of the project? What is your timeline? A typical research project can take several years to complete...time to generate new ideas and think about them critically before diving in. Research projects are designed...

...of Various Motifs is Critical for Initiation of Replication. Journal of Biological Chemistry, 273(14), ... replication machinery. For instance, the ori typically contains iterons that serve as recognition sites...Acinetobacter spp., Aeromonas spp., Agrobacterium spp., Alcaligenes spp., Aliivibrio salmonicida, Anabaena spp., ...Gram-negative and Gram-positive  Acinetobacter calcoaceticus, Actinobacillus pleuropneumoniae, Actinomyces...Aeromonas hydrophila, Agrobacterium tumefaciens, Alcaligenes eutrophus, Azotobacter vinelandii, Brevibacterium...pSa, pR388 Gram-negative  Acinetobacter calcoaceticus, Aeromonas liquefaciens, A. salmonicida, Agrobacterium...Agrobacterium tumefaciens, A. rhizogenes, Alcaligenes eutrophus, Enterobacter sp., Erwinia amylovora, E...

...connections to that population. Limitations of common genetically encoded neuronal tracers Neuronal tracers such...neurons. As compared to epitopes tags, FPs are intrinsically fluorescent and can therefore be used in live...tolerated by cells. They can be used for protein localization, isolation, and tracking experiments (Rizzo,.... Thus they have created antigenic protein tags called “spaghetti monster” fluorescent proteins (smFPs.... Indeed, to create the smFPs Looger’s team strategically inserted 10 to 15 copies of single epitope tags...darkened chromophores. These probes are both intrinsically fluorescent and can be detected with highly ...postsynaptic cell adhesion protein that plays a critical role in neural development. It belongs to a huge...

...tricks By Ashley Waldron While IHC protocols typically call for thin sections of tissue, the Wu Lab is ...therapy, Feng Zhang’s lab has developed a system called DIRECTED (Delivery to Intended REcipient Cells ...promising approach for experimental therapies and medical applications.  Find DIRECTED plasmids here! Strebinger...labeling can identify protein interactions or map a local proteome, but some applications have been challenging...control over when and where the enzyme is active, drastically reducing background labeling caused by the biotin...proximity labeling enzymes, TurboID and APEX2, are localized to different cellular compartments. They showed...of a cell. Lin et al. generated a fusion protein called iPAK4 that assembles into a slow-growing protein...

...The good news is that viruses are very valuable biological tools, and with the right safety considerations...infiltration into a cell. The twist is that the typical genetic cargo — the viral genome — is swapped, ...vector containing the cargo of interest is then typically transfected along with viral packaging plasmids...risk management when working with viral vectors. Typically, one day after transfection into the production...expression or integration resulting from transduction typically plateaus within a few days to a few weeks, depending...context you are targeting? Second, what is the biological outcome you want to achieve? For example, do ...swap out your virus type to achieve different biological outcomes. For example, some viruses integrate...

.... Factor Xa loves calcium, but metal-chelate matrices, not so much. Maybe a calcium-independent proteinase...This allows washing away of unbound material to calculate the amount of bound ligand (after subtracting ...subtracting out non-specific binding). Historically, glutathione-S-transferase (GST) fusion proteins have been immobilized...derivatives streptavidin and neutravidin) is for all practical purposes covalent. Therefore, protein immobilization... four biotin-binding sites per molecule so, theoretically, saturated avidin could form tetramers of biotinylated...well-controlled. The lack of site selectivity typically diminishes the apparent affinity for the ligand...However, large amounts of the target protein are typically required due to the relatively low efficiency ...

...transcriptase (RT), MarathonRT. Reverse transcriptases are critical tools for many fields of biology and enable the...Nanobodies are single domain antibody fragments typically engineered from heavy-chain only antibodies found... with specific genomic loci. He made use of catalytically inactive dCas9 by fusing it to an engineered...isolated and analysed. In this work, the authors specifically investigated protein binding at the TERT gene...his group from the University of Massachusetts Medical School have developed a group of plasmids (here...only 1 min. Using these lentiviral plasmids, catalytically inactive Cas9 (dSpyCas9) fused to APEX2 is expressed...by mass spectrometry allowing a researcher to specifically identify proteins that are enriched in the 20...

...humanistic and philosophical implications. As an example, a group at Caltech used an optical fiber together...Optogenetics is a toolset that lets you turn the electrical activity of neurons on or off using pulses of...photosynthetic or photosensory molecules that come from basically every branch on the tree of life. Our most recent...some of these mysteries. Another application is clinical; can we find ways to treat patients? Over a quarter...implant already. If we can use light to more specifically activate a set of neurons, maybe we could treat...modulate electricity. If you could selectively let in calcium or some other specific ion that would be interesting...Addgene Alerts box. References: Independent Optical Excitation of Distinct Neural Populations. Nathan...

..., you’ll first need to learn a little bit of theoretical background on the different parameters that your...and W describe the shape of a histogram, which graphically represents the time and intensity of the cell...Live/Dead gate to focus your analysis on what’s biologically active. After that, the next gates fully depend...depend on your individual experiment. Practical example: lymphocytes in a mouse tumor sample You made ...made it! So much about the theoretical background. Let’s dive into the praxis of gating strategies. As an... would work just as fine (Figure 4). As H and A scale in proportion (while H and W do not; see Figure ...presented with a trend of two populations with basically a smear in between. Again, it can depend on the...

...hybridoma monoclonals, we anticipate that our chemically identical hybridoma-derived antibodies will also work...specific ligand-binding functions, all key to basic biomedical research and drug development. Integrin structure...long legs that protrude from the cell membrane, physically connecting the extracellular environment and ...signal cascades, and allowing agile responses to mechanical forces in the cell’s microenvironment. The actin...and (C) extended-open. When a ligand binds, it typically shifts the integrin from its closed to its open...resulting in cells that elongated and morphed asymmetrically (Jo et al., 2022). By contrast, LVDP-binding...conferred less force, leading cells to spread into symmetrical circles. While elucidating the role of tension...

...situation in cells. Therefore, the localization of critical fusions (e.g. tubulin or connexin) has been...needed for Golgi localization, is occluded and therefore this protein is mislocalized. The APT1-mVenus... from Aequorea victoria and its variants are genetically encoded fluorescent probes. One of the limitations...ultracentrifugation or gel filtration is the most common analytical method. However, these may not reflect the situation... the POI. For example, the APT1-mVenus fusion localizes at the Golgi, whereas the mVenus-APT1 fusion does...function of the native protein that is tagged. The localization of the fusion protein can be verified and it...fluorescent protein fusion may never be able to act identical to the untagged protein, the benefits of being...

...or macromolecule. Biotin can be added enzymatically or chemically. Enzymatic biotinylation occurs naturally...Avidin is a glycoprotein that consists of four identical subunits that can each bind one molecule of biotin... Scientists have developed several methods to chemically biotinylate macromolecules of interest both in...acid functional groups in vivo via specialized chemicals (biotinylation reagents). There are a variety ...the specificity of the E.coli BPL, BirA. If you recall, BirA biotinylates only one lysine in the entire...using a biotinylated primer. Biotin can also be enzymatically incorporated during PCR using a biotin labelled...modification of exceptional specificity.” Trends in Biochemical Sciences, 24.9 (1999b): 359–363. PubMed PMID:...