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Basic Lab Skills and Know-how

A Quick Guide to pH, pKa and pI

They’re easy numbers to take for granted, so it’s a good exercise once in a while to remind ourselves what pH, pKa and pI stand for: pH—the measure of acidity. It’s the negative logarithm of the proton concentration. pKa—an association constant. It’s the negative logarithm of the ratio of dissociated acid and conjugated base, over…

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The Dos and Don’ts of Weighing Dangerous Chemicals

A lot of chemical reagents are relatively nonhazardous. But there are just as many that are extremely hazardous, which means you’ll want to take precautions to reduce any risk of exposure, repeated exposure and of course, accidental contamination of anything – or anyone – that walks out of the lab at the end of the…

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Let’s Dish About Soaps: A General Overview of Detergents

What do cell lysis, clean dishes, and gallbladders all have in common? Answer: detergents! These useful chemicals can solubilize fats and other proteins in water. They are the key to applications as varied as lysing cell membranes, extracting DNA, and solubilizing proteins for gel electrophoresis. To help you understand these important chemicals, we provide a…

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How to Clean a Tissue Culture Incubator

  A few years ago, I was doing research in a lab in Ireland. Our lab, among many others, was moving to a new building. Everything was chaotic. Half our equipment was in the old building and the new lab was creepishly empty. The fire alarm went off every few days. There was a constant…

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Protocols: Where Do You Get Yours?

Trying a new protocol is always a little daunting, especially if no one else in your lab is doing it. So it’s always good to find a tried and tested protocol from a reputable source before getting your hands dirty. Or at least one that can start you off in the right direction. It is…

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SuperSize It! Scaling Up Your Experiments

Life in the lab is easy-peasy when you are only prepping a handful of tubes. But what if you need to scale up to 10’s or even 100’s of samples? Scaling up your experiments can have some expected and some not-so-expected, leaving you in a lurch, consequences. Read through our tips so you aren’t caught…

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How to Check the Accuracy of Your Pipette

How much time do you spend thinking about the accuracy of your pipette? Probably not much. It’s one of those things that get brushed aside in the heat of experimentation. Pipetting accuracy though, is critical to successful experiments–especially in sensitive experiments. For example, qPCR relies upon accurate pipetting—calculations depend on having the same amount of…

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10 Ways to Abuse a Pipette

It seems like every movie that needs a shot of a scientist doing their sciencey-thing either gets the person to pour one pretty liquid from one flask into another or to stare intensely at a test tube with a look of knowing so much more than you ever could. Another favorite shot is of someone…

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Agarose versus Polyacrylamide: Not All Gels Are Created Equal

Like athletes running on turf versus sand, the gel you run your DNA through can highly affect your results. The two main types of gels that people use for DNA electrophoresis are agarose and polyacrylamide (PA) gels, but figuring out the differences can be confusing. Basically, you choose a gel based on two main factors:…

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Take Care of Your Tools: How to Clean a Pipette

Like a Jedi’s light saber, your pipette is an extension of your arm and the lifeline to your (lab) existence. You probably should give it a little TLC once in a while to keep it free from contaminants.  Especially if you are doing experiments involving things like gene expression analysis. Sure, you can use filter…

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Freeze-Thaw Cycles and Why We Shouldn’t Do It

Freeze-thaw—you know it’s bad for your samples, don’t you? While working in the lab, you have most likely heard someone say ‘aliquot your protein/cells/DNA/RNA to avoid too many freeze-thaw cycles.’ But do you actually understand why? You probably thought that avoiding freeze-thaw cycles had something to do with damaging cell structure as well as proteins…

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Buying a Secondary Antibody: Why all the Choices?

So you grab a quick 5 minutes in between lectures to sit down and tackle an item on your to-do list: order a secondary antibody for an upcoming experiment.  But when you start to search your favorite secondary antibody provider’s website, you realize it is not going to be a 5 minute job.  Conjugated, F(ab’)2…

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Tips for Heating up Agar in the Microwave

One of our readers posted the following question to us and we decided to pass it along to everybody’s favorite microbiology expert, Aunt Yersinia: For one year I am working in different research laboratories, after I got from school. I keep wondering why EVERYBODY is using pre-made Agar solutions for pouring plates, and EVERYBODY is…

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What Makes a “Good” Laboratory Buffer?

Just about any molecular biology experiment will involve the action of enzymes or other active proteins. And when enzymes are involved, the pH of your experimental environment is going to change. This is because most enzymatic reactions involve the loss or gain of hydrogen ions (protons), which modifies the pH of the environment. Biological systems…

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A Quick Primer on Enzyme Kinetics

As biological catalysts, enzymes transform target substrates into products. Enzyme kinetics is the rate of that transformation. By understanding how an enzyme’s behavior is affected, you can figure out how it functions in physiology or fails to function in disease. Now it gets complicated… What Affects an Enzyme’s Kinetics? In the first place, most enzymes…

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