Three makes a happy family
The core Midori Green molecule has been formulated into three different stains optimized for your lab’s needs. First, there is Midori Green Advance – which offers an excellent signal-to-noise ratio and good sensitivity for even short nucleic fragments. Midori Green Advance is added into the agarose gel prior to running samples (much like ethidium bromide) and provides sensitivity of detection on par with EtBr when visualized with blue LEDs, or Nippon Genetics’ novel blue/green LED technology. The second dye, Midori Green Direct, is designed to simply mix with your sample and load onto a stain-free gel. Midori Green Direct has the loading dye included and detects nucleic acid fragments to a similar, if not slightly better, level as Midori Green Advanced. The newest member of the family is Midori Green Xtra. Like “Advance”, Midori Green Xtra is added to the gel and buffer. It’s chemical structure is optimized for Blue/Green and Blue LED light, leading to unbeatable fluorescence signals of DNA and RNA in agarose gels. All three dyes are compatible with UV-light, but are slightly less efficient when using UV rather than the non-damaging visible excitation light of Blue and Blue/Green LEDs. Most important for labs, Midori Green Xtra does not stain the agarose gel, leading to an excellent signal-to-noise ratio, making the detection of even the minutest quantities of DNA or RNA possible ( and certainly better than EtBr).
Thoroughly tested for your safety
Another big advantage is safety. Midori Green Advance Nucleic Acid Stain is a new, safe alternative to traditional ethidium bromide(EtBr) stain for detecting dsDNA, ssDNA and RNA in agarose gels. Nearly identical to EtBr in performance and use, Midori Green is much less harmful to living organisms. As compared with EtBr, which is known as a strong mutagen, Midori Green causes many fewer mutations in the Ames test. When compared with spontaneous mutations caused by water in the Ames test, Midori Green’s rate was only slightly beyond the standard deviation range. In addition (and in contrast to EtBr), Midori Green scores negative in the mouse bone marrow micronucleus test and in the chromosome aberration test, which indicates that it’s considered non-carcinogenic. And for those who prefer to be safe rather than sorry, Midori Green has been tested for latex/nitrile glove penetration, in which both materials show negative results—even after 6 hours of exposure. Most importantly, Midori Green is not considered hazardous waste, and can be disposed of according to standard laboratory procedures.
Safer for you and better for your subcloning
By using safe Midori Green dyes and safe Blue/Green LED illumination you can improve your subcloning transformation efficiencies by THREE-FOLD. In this example, a plasmid vector was double digested with suitable restriction enzymes to create two sticky-ended DNA fragments: the lacZ gene (3,536 bp) and the backbone of the vector (4,318 bp). Equal amounts of digested DNA were electrophoresed on 1% agarose gels. The gels were stained with either ethidium bromide or Midori Green Direct gel stain according to the corresponding manuals, and then viewed using either a UV transilluminator or the FastGene Blue/Green LED Illuminator, respectively. The two DNA fragments were excised from the gels and purified using a silica membrane based purification kit. The lacZ gene and the vector backbone were religated using T4 DNA ligase transformed into DH5a cells and plated onto selection plates. The total number of blue and white colonies was counted to evaluate cloning efficiency. Each experiment was conducted in triplicate, and the average cloning efficiency was determined. Midori Green Direct resulted in dramatic increase of positive transformants.
Midori Green Can Boost Your Cloning Results!
Ethidium bromide is typically used in conjunction with a strong UV light source to excise DNA bands for purification prior to the ligation reaction. Short wave-length light is known to cause thymidine dimers and damage the DNA. The extent of this damage is not always appreciated. High energy light wreaks havoc on a DNA fragment in mere seconds. As can be seen below, after only a 15 sec exposure of DNA in a standard agarose gel, cloning efficiency starts to drop. And after a 30 sec exposure your cloning experiment is all but dead! In contrast, the cloning efficiency of protocols that use blue or blue/green LEDs are completely unaffected by this deleterious effect. If your lab isn’t able to break itself of its ethidium bromide habit, using a Blue/Green LED illuminator (or imaging system) should have an immediate positive impact on DNA integrity and cloning efficiency.
UV Transilluminators Kill Cloning Experiments
Now with equal of better sensitivity as compared to EtBr
All three dyes can stain single- and double-stranded nucleic acids with sensitivity and protocols similar to that of EtBr. This makes it a no-brainer as a drop-in replacement for your lab’s current protocols. Not only can you use your existing UV transilluminator and filter sets, Midori Green dyes work best when matched with blue or in particular, Blue/Green LED Gel Illuminators and Imagers. These environmentally-friendly light tables are the perfect complement for Midori Green stains, as you can work shield-less and goggle-less when excising bands or imaging migration. And because blue or green light does not cross-link DNA, there is never a worry about damaging DNA during cloning and photographing sessions.
Comparison of sensitivity between MIDORIGreen Advance (left green) and Ethidium Bromide (right red) using a Blue/Green LED Transilluminator.
Comparison of sensitivity between MIDORIGreen Direct (left green) and Ethidium Bromide (right red) using a Blue/Green LED Transilluminator.
Midori Green DNA Stains
|Contents||1ml tube (20,000x)||1ml tube
(10x loading dye)
|1ml tube (25,000x)|
|Add to Gel||Yes||No||Yes|
|Add to Sample||No||Yes||No|
|UV Transilluminator Compatible||Yes||No||No|
|Blue LED Illuminator Compatible||Yes (side illuminationrecommended)||Yes||Yes|
|Storage||1 Year in the dark at 4°C|