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Techniques

Tissue Embedding Throwdown: Paraffin vs OCT vs Resin

Tissue embedding and sectioning is a backbone of many biological research labs. While commiserating with other grad students over tedious hours spent in the lab, you’re probably aware that there is more than one way to slice up a chunk of tissue. We’ve previously introduced what to consider when choosing a tissue embedding medium and…

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The Inhibitors Haunting Your PCR

It often happens that you do everything right with a PCR. You have perfectly isolated template DNA, used sterile tubes and tips, used clean reagents, and said a quick prayer to the PCR Gods. And still, something unknown messes up your results. This unknown at work is generally a PCR inhibitor. Before you blame it…

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Codon Optimization for Increased Protein Expression

The Genetic Code: A Universal Template for Protein Translation All known organisms share the ‘central dogma’ of molecular biology. DNA is transcribed into mRNA that is translated into protein. During the discovery of the genetic code, Francis Crick hypothesized that translation required a mediator to aid mRNA-guided translation according to a number of specifics. Amongst…

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Antibody Validation

Not all antibodies are valid for every experiment and condition, and they must be validated for the specific application and species. Currently, there is no standard means of “antibody validation,” and this can greatly impact experimental reproducibility and reliability. Journals and granting agencies have taken steps to address this gap. Many now require you to…

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How to Use CellProfiler for Cell Imaging

Are you trying to figure out how to calculate intensities of fluorescently-labeled single cells? Do you have cells at high densities or present in clusters? Are you worried that your current cell imaging analysis software is unable to mark clear boundaries around each cell in a cell cluster? Don’t fear, because CellProfiler 2.1 is here to…

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Cre-loxP Recombination Essentials Part 2

The Cre-loxP recombination system is routinely used for the generation of mouse knockouts. In part 1 of this mini-series, I introduced the concept and applications of Cre-loxP. As with any other technology or research tool, it has limitations and pitfalls that need to be considered while planning experiments or interpreting results. This article will take…

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A Crash Course in CRISPR-Cas9 Editing in Drosophila

CRISPR-Cas9 has become a magic tool for molecular biologists, transforming genetic engineering from a once unbelievable dream into tangible reality. Today, you can easily edit primary cells or cell lines within a few weeks with well-established protocols or others’ hands-on advice. However, no matter how many success stories you find online or hear at seminars…

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How to Design a CRISPR Experiment and Start Genome Editing

CRISPR and the CRISPR Associated system (Cas) are powerful gene editing technologies. Originally identified and characterized in bacteria, the endogenous CRISPR systems act as an RNA-based defense mechanism against invading phage DNA. CRISPR cas9 gene editing was adapted for genome editing in 2013 and has since been exploited for its ability to generate targeted double-stranded DNA…

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NGS-Based HLA Typing Delivers More Comprehensive Information

Used for matching organ transplants to donors and other applications, human leukocyte antigen (HLA) typing is rapidly shifting from older methods to NGS technologies. This is a major step forward, as more complete views of the highly polymorphic HLA genes provide a deeper understanding of how a person’s natural genetic variation might affect transplant matches…

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PCR Pitfalls: The Devil is in the Details

PCR was actually one of the first lab techniques I learned as an undergrad. Despite being sometimes labeled as a pretty basic lab skill, PCR doesn’t always work as expected. This “fickle” success is due to small details or hidden hazards within the PCR workflow that can cause your seemingly uncomplicated experiment to fail.  This…

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A Primer on Phage Display Libraries

Phage display – the process of genetically fusing antibody fragments with phage to identify binding partners to your protein of interest – was covered pretty thoroughly here over the past few months. The success of this assay predicates on creating a diverse library of up to 1012 genes coding for these antibody fragments. Despite being…

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Sheath Pressure: Nozzle Size Does Matter

Hello again, fellow Flow Cytometry Fan! It looks like you have your experiment all planned out, including staining protocols and gating schemes, and are ready to get some paradigm-shifting data. But before we start “plugging-and-chugging” samples through your cytometer of choice, we need to make sure that the nozzle size and sheath pressure are set…

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How to Obtain Stellar Staining with Fluorescent IHC

They say “a picture is worth a thousand words.” This is especially true in the case of fluorescent immunohistochemistry (IHC). With the flip of a microscope filter, you can gaze into a brightly colored galaxy of red, green, and blue pixels, waiting to be captured and presented in your next publication. If you are interested in…

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How to Test the Efficiency of your sgRNA

To successfully edit your genome of interest, one critical step is to test the sgRNA you have designed. Fortunately there are programs that have been developed such as CRISPRscan for zebrafish, SSC, Sequence Scan for CRISPR, or WU-CRISPR that you can use to predict the efficiency and the suitability of the sgRNA. However, the prediction…

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Cre-loxP Recombination Essentials Part 1

You might have heard of the Cre-loxP system even if you are not directly working with genetic manipulation. The Cre-loxP system is an ubiquitous technology for genetic manipulation and a mainstay in mouse research labs. With this system you can delete genes in cells, specific tissues and even whole organisms! You can start to master this system by…

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ELISA: How I Wonder What You Are

My phone’s email notification went off, and I rolled over in bed to look at the clock. Saturday, 5 am. Wonderful. Who would email me at that hour? It had to be my undergraduate research PI. I unlocked my phone. Yep. Doesn’t he ever sleep? Dear Casey: We are launching a new collaborative project in…

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Meeting the BioPython

The Biopython Project is an amazing initiative that helps scientists use Python for bioinformatics – and it’s exceptionally easy to learn! You can access online services, parse (read) different file types, analyze, and do a bunch of fun stuff with your data with Biopython. The people behind the project have put in a lot of…

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