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Techniques

Quantifying Allele-Specific Gene Expression Using PCR-Based Methods

Allele-specific expression can occur for various biological reasons, such as gene imprinting, or differential transcription caused by mutations, or single nucleotide polymorphisms (SNPs), or epigenetic alterations. Traditional end-point RT-PCR or qRT-PCR-based methods only detect overall levels of mRNA expression from a given gene rather than mRNA transcripts originating from individuals. If your project requires more…

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Guide to Making and Storing Competent Yeast Cells

Yeasts, such as Saccharomyces cerevisiae, Schizosaccharomyces pombe and Pichia pastoris, are routinely used in biology research labs around the world. Yeasts are easy-to-culture, unicellular eukaryotes, and make excellent model organisms because of the similarity of their genes and proteins with those of their mammalian counterparts. Yeast cells are used to study gene function, protein interactions,…

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From Cells to Scope: Chamber Slide Immunochemistry

Immunolabeling is the tried-and-true immunochemistry method of getting the stain you want onto the molecular target you want. Whether that target is contained within a large region of tissue (immunohistochemistry) or inside a single cell (immunocytochemistry), the ability to accurately label large numbers of samples will simplify your workflow and help you to achieve excellent…

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Bacterial Transformation Troubleshooting for Beginners

The first time I did a transformation was when I worked with site directed mutagenesis. I cloned a protein sequence into the p15TVL vector, created my mutants (but that’s another story), and was finally ready for the next step: transformation and expression of my desired protein. Little did I know that my enthusiasm would fall…

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An Introduction to In-Gel Zymography

Enzymes are special among proteins. It is not enough to detect them. You need to know their activity level. If you have devoted a substantial part of your research to studying proteases, like I did, you’ll know how crucial it is to choose an appropriate enzyme assay. There’s a heap of lab techniques out there…

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What’s in Your Cell Culture Medium?

Anyone who has performed mammalian cell culture will recognize the typical media recipe: 1 bottle of DMEM, 10% serum, a few other magical ingredients, throw it together and put it on your cells to keep them alive and happy. However, do you know what each ingredient does? Let’s look at the common ingredients in cell…

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Lasers for Confocal Microscopy: Part II

Continuing from our first article on lasers for confocal microscopy, we will now discuss two specialized types of lasers: lasers for two-photon excitation and tunable, white light lasers. We will also discuss the applications of the two lasers. Lasers for Two-Photon Excitation The two-photon absorption phenomenon was first described for microscopy in 1931. Here, the…

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How to Survive a Difficult PCR

I am sure many of you have been there. Everything is going smoothly, and your project seems to be working out perfectly. And then there is this one PCR. For some reason, it just won’t work. It is a black dot on your record. Even though I have a scientific mind, I have to be…

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Alphabet Soup for Bacteria!

In its simplest form, a bacterial growth medium is designed to support the growth of bacteria. Depending on which bacteria you want to culture, you may have a range of different media to choose from, each containing a rather unique blend of sometimes surprising (and odd!) components! In this article, I will take you through…

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Handling Your Bacteriophage in a Sea of Bacteriologists

When I first told a lab colleague I was going to be doing phage work in a lab that had otherwise only dealt with bacteria, I was met with expressions of awe, and then fear. Being that a bacteriophage is essentially a predator of bacteria, this reaction is legitimate for a bacteria-loving scientist. Also, we…

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How to Manage Greenhouse Pests

In my last article I introduced what it takes to work in a greenhouse. While for the most part it is a pretty simple work environment, there is one aspect that warrants a more in-depth discussion: greenhouse pests. It doesn’t matter if the pest is an insect, virus, or bacteria, it can very quickly bring…

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Amplify Your PCR Success with the Right PCR Instrument!

Nowadays, almost every biology lab has a PCR instrument — from portable, battery-operated machines, to “PCR-by-water baths”, do-it-yourself PCR, or familiar vendor packages, including those with real-time quantification or droplet digital capabilities, DNA amplification depends on a robust thermal cycler. If you are looking to upgrade, add to, or even replace the lab’s current PCR…

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How UV Radiation Causes DNA Mutations

We all know that we are supposed to put on sunscreen in the summer months to protect ourselves from skin cancer, and the connection between sun exposure and cancer is well documented (Koh et al., 1996; Armstrong and Cust, 2017). UV-A and UV-B rays from the sun interact with the DNA in our skin and…

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The Trouble with Disease Models: Case Study in Diabetes

The development of new drugs requires reliable and robust animal disease models. Since the cause of many diseases is still unknown, it is often difficult to identify adequate and predictive disease models. For example, researchers developing treatments for neuropsychiatric diseases such as Parkinson’s and Alzheimer’s face a particular challenge given the subjectivity of many of…

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