“Dear Tech Serv,
We would like to detect DNA collected from swabs rubbed on the inside thighs of frogs. What would be the best DNA extraction kit to use for this?”
“Hi Tech Serv,
I need to find out a suitable kit for extracting DNA from bird fecal samples. Can I use ReliaPrep™ gDNA Tissue Miniprep System for that?”
These are just some examples of unconventional sample type inquiries that the Promega Technical Services Team receives regularly from scientists around the world. Many of these inquiries land in the hands of Technical Services Scientist, Paraj Mandrekar (a.k.a. “sample type guru”). Continue reading
Isolating DNA from plant tissues is difficult for many reasons. Unlike animal cells, plant cells have rigid cell walls, often made of tough fibrous material, and contain proteins and enzymes and other compounds such as polysaccharides and polyphenols that play a role in different cellular processes. These compounds can interfere with DNA isolation as well as downstream applications such as PCR. For these reasons, DNA isolation methods that are used successfully for other sample types may not work well to isolate DNA from plant material. Continue reading
Formalin-fixed, paraffin-embedded (FFPE) tissue samples are extremely common sample types. In this form, tissue is easy to store for extremely long periods of time and useful for immunohistochemical studies. Additionally FFPE samples are fairly inexpensive to produce. However the formalin fixation procedure, which was developed long before the advent of molecular biology, results in chemical crosslinking of nucleic acid and protein molecules inside the cells. This crosslinking presents a challenge for isolating intact, high-quality nucleic acid DNA; so getting at the wealth of molecular information within an FFPE sample can be difficult.
In the upcoming webinar “Successfully Overcoming the Challenges of Working with FFPE Samples”, Dr. Trista Schagat of Promega Corporation discusses some of the key considerations for anyone who is attempting to isolate nucleic acid from FFPE samples. Continue reading
Wish I had one of these when I was at the lab bench…
Back in the dark ages, when I was a graduate student, my idea of “automated” plasmid DNA extraction involved performing home-brew, “toothpick preps” in “strip tubes” or , if I was really feeling ambitious, a 96-well plate. I would get just enough DNA to check for the presence of an insert, but the quality of the DNA was too low and the quantity too small to even consider using it for any other downstream experiments like amplification. And increased throughput for other nucleic acid extraction needs? Nope. If I wanted genomic DNA, RNA or high-quality plasmid DNA, I spent time with columns and tubes, giving each sample my undivided individual attention. Remember cesium chloride preps for RNA isolation? Even with the advent of column purification, which greatly simplified and standardized my protocols, nucleic acid purification was still a manual task that required a lot of time and effort to get the high-quality product I needed. Doing the experiments that would answer the questions that I really wanted to ask (those “downstream experiments”), meant spending time at the bench performing careful (if tedious) work to isolate and clean up the highest quality nucleic acid possible. Even then inconsistency in sample prep could wreak havoc on downstream work. Fortunately, for the modern scientist, personal, bench top automation, has progressed far beyond the toothpick and the strip tube to quality-tested, reliable nucleic acid extraction platforms like the Maxwell® Rapid Sample Concentrator (RSC). The Maxwell® RSC improves sample preparation consistency, eliminating variability associated with manual handling, and your downstream results will reflect this consistency. With the RSC you can extract DNA or RNA from up to 16 samples in approximately 1 hour and viral total nucleic acids in less than an hour. The instrument is easy to use: simply load the sample, push a button and walk away. Cross contamination is minimized and the instrument is supported by the Promega technical support and service you have come to trust over the past 35 years. Do you want to know more about how the Maxwell® RSC can become your research partner, giving you the freedom to focus on the work that interests you the most? Register for the free webinar and see the data for yourself: high-quality nucleic acid that performs well in downstream analyses. You’ll even be able to view videos illustrating RSC setup and use. Register today for the free webinar.
Guest Post from Promega Technical Services Scientist, Caroline Davis.
On a snowy day in January, someone stole the cookies that were to be served with lunch from the Rome Corners Intermediate School cafeteria. The kids were distraught. What should they do? Luckily, the Green 2 Team science class was there with Promega’s Technical Service Outreach team (and Paraj Mandrekar, Senior Research Scientist and Green 2 Team Dad) to help.
The students realized that the thief had taken a bite out of a strawberry and left part of it behind, along with his DNA. After a short discussion on what DNA is and why you would want to isolate DNA, the 6th graders extracted DNA from strawberries using household reagents under the guidance of the Promega scientists. The students used pipettors, beakers, microfuge tubes and flipper racks, giving the students a glimpse of the tools that scientists use everyday in in a molecular biology lab. Continue reading
Yesterday I listened in on the Webinar “Getting the Most Out of Your DNA Analysis from Purification to Downstream Assays”, presented by Eric Vincent–a Product Manager in the Promega Genomics group.
This is the webinar for you if you have ever wondered about the relative advantages and disadvantages of the many methods available for DNA purification, quantitation and analysis, or if you are comparing options for low- to high-throughput DNA purification. Eric presents a clear analyses of each of the steps in a basic DNA workflow: Purification, Quantitation, Quality Determination, and Downstream Analysis, providing key considerations and detailing the potential limitations of the methods commonly used at each step.
The DNA purification method chosen has an affect on the quality and integrity of the DNA isolated, and can therefore affect performance in downstream assays. Accuracy of quantitation also affects success, and the various downstream assays themselves (such as end-point PCR, qPCR, and sequencing) each have different sensitivities to factors such as DNA yield, quality, and integrity, and the presence of inhibitors. Continue reading
In honor of Halloween, here is a Top Ten Uses of Pumpkin list for your enjoyment:
10. Means of transportation on the high seas or emergency flotation device (pumpkin boats; see the video).
9. Elementary Math Lessons. Determine circumference and radius. How much does a pumpkin weigh? Estimate the number of seeds. Check out pumpkin math ideas here.
8. Cholesterol-lowering snack. After ruthlessly scooping out the innards of a pumpkin, clean the seeds, bake them in the oven and enjoy your healthy snack. Pumpkin seeds contain phytosterols, compounds that that have been shown to reduce levels of LDL cholesterol, as well as magnesium, a mineral needed in the diet.
7. Physics Laboratory. Pumpkin Chuckin’ Contest (video). Continue reading