"Viable But Non-Culturable (VBNC)": Zombies of the Bacterial World

“Viable But Non-Culturable (VBNC)”: Zombies of the Bacterial World

Imagine that you want to test the efficiency of an antimicrobial treatment in inhibiting a certain bacterial pathogen. As part of the experiment, you expose the bacteria to the treatment and monitor the cultivability of the microorganism by counting the number of colony forming units (CFU) formed on culture media. If the microorganism is sensitive…

Protein

8 Tricks to Improve Your Negative Staining of Membrane Proteins

Negative staining of proteins is a versatile tool for structural biology. The sample preparation protocol is simple: the sample is embedded in a heavy metal stain that gives rise to increased specimen contrast. Thus, negative staining is a very convenient method to assess sample homogeneity, formation of macromolecular complexes, or quality of protein preparation. Conventional…

Bottles water to highlight the different types of water in the lab

Water your choices? Understanding Types of Water in the Lab

If you are working in a scientific laboratory, it is very important to be aware of the various types of water available, because the purity may not be acceptable for your specific experimental application. In most labs, there are generally two types of water piped in to the sinks: Industrial Water Industrial water is non-potable…

outsourcing research

Outsourcing Research: Should Your Experiment Spend Some Time Away from You?

As a researcher, it’s satisfying to manage your own projects and do the bench work yourself. After all, if you don’t have experience with a technique, you’re usually expected to figure it out (with or without direct supervision). In some situations, dealing with difficult molecular techniques is simply part of the job description. The scientific…

Optimize Bacterial Protein Expression

Optimize Bacterial Protein Expression by Considering these 4 Variables

So, you have successfully cloned your gene of interest and are eager to purify buckets of protein. No matter your eventual application—kinetic experiments using a SPR instrument, structural analysis using X-ray crystallography, or any other experiment—you’ll need to express your protein first.  Now, it’s time to put your expression plasmid into E. coli and get…

human clinical samples

Four Tips for Working with Human Clinical Samples

While using human clinical samples in your research can provide robust and heterogeneous results applicable to larger portions of the population, working with these samples presents its own set of challenges. Here are some tricks I have learned to help isolate and grow your cells of interest while eliminating stromal, blood, or other undesired contaminants….

sensitive qPCR

SPUD’s Your Bud When it Comes to Sensitive qPCR

There’s piloting a brand new technique for the first time. Then, there’s jumping through hoops trying to get an established lab technique to work. The former, in contrast to the latter, is expected to be fraught with hardships. Yet troubleshooting an old lab technique that isn’t working anymore, is frustrating at a whole new level….

How to Start Using Coding to Automate Image Analysis Part 2: Batch Processing Multiple Images

How to Start Using Coding to Automate Image Analysis Part 2: Batch Processing Multiple Images

In Part 1 of this article, I introduced you to using code for basic image manipulation in ImageJ and working with the command recorder to expand your coding vocabulary. I covered how to make a simple macro, how to edit it and then save it to be run again another time. If you skipped the…

lac expression

How to Shut Off Background Lac Expression in LB

Here’s a tip that you may find useful if you are expressing proteins in E.coli using a lac promoter-based expression system, e.g. pET, in LB medium (L-broth). Lac expression systems are typically induced in the lab using IPTG (isopropyl-beta-D-thiogalacto- pyranoside), which is a non- hydrolyzable analog of lactose, the natural inducer of the lac operon….

Screening for Cloned Inserts

Quick and Dirty Screening for Cloned Inserts

For identifying positive clones from a plasmid cloning procedure, the routine of performing a mini-prep and then checking the putative clones by restriction digestion is most commonly used. Of course, if you need to screen a large number of clones, another option is a colony PCR to identify positives, followed by restriction digests to confirm….