Isolating DNA from plants: Teaching skills infused with concepts

Isolating DNA from plants: Teaching skills infused with concepts

My first job after college in 1982 was teaching high school biology.  I genuinely enjoyed teaching, but soon I started to miss more in-depth science.  After three years, I left teaching and entered graduate school at Rutgers to study microbiology and molecular genetics, however my interest in teaching followed me.  I was fortunate to have Dr. Douglas Eveleigh as my mentor, where he not only nurtured my passion for science with my research, but also encouraged and allowed me to teach at a higher level.  Aside from teaching lab and lecturing in general microbiology, our group established the first continuing education hands-on courses in molecular techniques at Rutgers.  In the mid-1980s cloning was still novel, and as Rutgers sat in the heartland of U.S. pharmaceutical industry, our courses were very well attended.  After earning my degree, I turned this endeavor into a full-time business and added courses and part-time faculty to meet the growing demand for practical hands-on training.  Over the next decade, universities began to offer similar courses and enrollment waned.  Looking for other opportunities, I taught my last class in 1998.

The classes we taught focused on detail.  We didn’t use kits or pre-packaged experiments.  We made all the reagents and made a point of explaining everything to the course participants from what they were using to why.  Nothing we did came out of a box.  It was my belief then, as it still is today, that by understanding the mechanisms and details of experimental processes troubleshooting issues become easier.

Today our company is very different.  We no longer offer hands-on training sessions; we now make products and work out custom solutions for our customers.  But the teaching mindset is still in me, in my DNA as it were.  While my scientists are good, they troubleshoot problems for clients and come up with some great solutions, I noticed a troubling pattern.  Many of them came out of college having been taught only using commercial kits.  They couldn’t explain how the kits worked or the roles of the various components.  This was something we had to address.  Consequently, when we use kits, I explain what is going on and why they work.  Ironically, we now manufacture molecular biology kits.

OPS Diagnostics makes Synergy™ kits for plant nucleic acid isolation.  Synergy™ uses the same principles as traditional plant DNA isolation protocols, but there are significant differences.  What sets Synergy™ apart is not just its performance, but how effectively it can be used as a teaching tool.  It is a safer alternative to traditional plant DNA isolation methods and can be used to highlight several important biological principles.  Thus, I thought it would be worthwhile if I dust off my instructor’s hat and explain how Synergy™ can be used for teaching.

One of the most widely used traditional methods for plant DNA isolation is as reliable as it is risky.  It typically relies on cryogenically grinding leaves, extracting with organics, and alcohol precipitating (Figure 1).   The most popular method involves grinding leaves in a liquid nitrogen chilled mortar and pestle, followed by creating a plant slurry with a CTAB buffer, phenol/chloroform extractions, and finally alcohol precipitation.  This method works well with a wide variety of plants, but in a classroom, it is an accident waiting to happen.

 Figure 1.  Traditional plant DNA isolation process using LN2, CTAB, and Phenol/Chloroform extractions (Created in https://BioRender.com).

In the classroom, the traditional cryogenic, phenol/chloroform extraction method is impractical.  Aside from the dangers of using liquid nitrogen, phenol can cause severe acid burns, and chloroform is carcinogenic, not to mention banned in many schools.  Add to this the cost and hassle of disposing of the phenol and chloroform.  However, the principles associated with cryogenic grinding and phenol chloroform extraction should be taught.

Our Synergy™ kits, though not our intention, turned out to be a very powerful tool for teaching these concepts associated with plant nucleic acid isolation.  Our process uses grinding (though bead beating), CTAB chemistry, an organic phase extraction, albeit a solid phase extraction, and alcohol precipitation (Figure 2).  However, aside from the major steps of the process, the chemistry involved can be highlighted as well.

Figure 2.  Synergy™ DNA isolation process (Created in https://BioRender.com).

Each step in the isolation process, of Synergy™, can be used to teach both technique and concept.  The beauty is that it is safe, and fast, for those instructors facing time constraints.  The parallels to the traditional method are evident, however the opportunity is available to explain how the process works.  To help, we’ve prepared a lesson with support information for instructors who might be interested.  On the following link we’ve provide a basic lesson plan, notes, and PowerPoint for whoever may find it useful. 

 This information can be found here: link.