One of the most common tasks in molecular biology is cleaning up DNA from aqueous solutions to remove buffer salts, enzymes or other substances that could affect downstream applications. Examples include cleaning up PCR reactions, digests or other enzymatic treatments and cleaning up genomic or plasmid DNA contaminated with cellular proteins/debris. There are several ways to approach DNA clean-up, here are five of them. Read more »

I was becoming a bit bored with the tedium of column-based kits, so when I had to isolate genomic DNA from a range of micro-organisms for a recent project I decided to try something new.

Invitrogen’s ChargeSwitch genomic DNA isolation kit, which uses magnetic beads to separate the gDNA from the cell debris, seemed interesting so I thought I’d give it a go. Read more »

The hysteria among molecular biologists about our old friend ethidium bromide has long been an irritation to me. Researchers are rightly wary of this potential carcinogen. More recently this wariness has been whipped up into a witch hunt by companies touting “safer” alternatives and disposal methods. While I don’t for a minute think that we should all throw our gloves away and bathe in the stuff, I think that it’s time for an informed reality check about the dangers, and the myths about ethidium bromide. Read more »

If you do a lot of heterologous protein expression, take a look at Eurogentec’s CherryExpress Kit. Based on the T7 expression system, the CherryExpress vector has a sequence encoding a small red polypeptide (the heme binding part of cytochrome) fused to the promoter. When your favorite gene is cloned in, the resulting fusion protein is bright red, allowing easy identification of clones expressing your gene. Even better, protein expression level can be quantified at 480nm and the highly soluble peptide could even improve the soluble expression of your protein. Tasty.

Isn’t it a pain digesting, purifying and dephosphorylating your cloning vector prep to eliminate prevent high background in your ligation/transformation? A new generation of positive selection vectors promises to eliminate all of that hassle by killing off any vector that has not taken up the insert you are trying to clone. Read more »

The past few years have seen the emergence of custom gene synthesis as a useful but expensive service available for molecular biologists. Recently, the number of companies offering custom gene synthesis has exploded, pushing the cost of the service down to much more affordable levels. Read more »

Equipment for photographing DNA gels stained with ethidium bromide (or other fluorescent dyes), doesn’t have to cost thousands of dollars. These days, great pictures can be obtained with a standard digital camera and an orange filter. Here’s how. Read more »

What do you get when you cross a Pyrococcus DNA polymerase with a dsDNA binding domain? …a highly processive, high fidelity, lighting fast PCR work-horseThose Finnish wizards at Finnzymes have made that work-horse a reality with their Phusion polymerase. I had been meaning to try out this enzyme for quite a while, but never got around to it, then a problematic 11 kb amplification brought it back to mind. Read more »

Zymo research have launched a new plasmid miniprep kit that not only is has the coolest name of any kit on the market but is, the manufacturers claim, the fastest means of plasmid purification available. Read more »