New tools from Molecular Probes

A new quantification kit for RNA features a very specific fluorescent dye - RiboGreen​ - that allows the amount of RNA present to be accurately quantified, even if the sample is contaminated with DNA, according to Molecular Probes. The kit includes DNase I, an enzyme which breaks down DNA and allows RNA to be purified and measured from a sample even if the proportion of DNA to RNA is 1:1.

The latter issue is extremely important, as reagents that bind to nucleic acids have been known to lose selectivity if their target - DNA or RNA - is present in lower or equal concentrations. Molecular Probes​ also markets a version of the kit without DNase I that is used to quantify pure RNA samples.

Meanwhile, Molecular Probes also introduced a safer alternative to ethidium bromide staining for staining DNA gels. The latter stain is known to have mutagenic properties, and it may also raise the risk of cancer or birth defects.

The new stain, called SYBR Safe​, is compatible with both agarose and polyacrylamide gels and is said to be twice as sensitive as ethidium bromide. Because it is less mutagenic, waste disposal is easier, safer and less costly than with the older stain, and Molecular Probes notes that environmental safety studies in the US have classified it as non-hazardous waste.

Finally, the company introduced Coomassie Fluor Orange​, a reagent for staining proteins in SDS-polyacrylamide electrophoresis gels. The company claims that the stain is at least as sensitive as colloidal Coomassie stains - picking up as little as 8ng of protein per minigel band - and superior to Coomassie brilliant blue stains.

Unlike colloidal Coomassie stains, the gels do not need washing before staining or destaining after (which with some cases is an overnight procedure), and reagents are premixed and ready-to-use. Staining occurs in as little as 30 minutes, versus three hours or more with some colloidal products.