Getting Nettled

One of the most prolifically adaptable plants around has got to be the stinging nettle, which is at home in Europe, Asia, North America and northern Africa.  It’s also one of the most prolifically named: Urtica dioica goes by several other species names that appear to be in a state of constant revision. (Maybe I can get a little help from the taxonomists on this one–is this a case of many plant morphologies with a single genome that people have confused for unique species, or is it a case of many people having something they call “stinging nettle” near them, that’s actually a range of species within the Urtica genus?)

By any alias, the stinging nettle is an interesting mix of benevolent and malicious–an intensely nutritious food plant chock full of iron, calcium, and vitamins A and K (see recipe below)…but guarding its benefits behind an armor of fine stinging spines. Continue reading

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Mung Beans: From Dinner Table to Lab Bench

So today I was doing an experiment, and realized the tube I was pipetting from was a perfect plant topic: mung bean nuclease!

You know mung beans.  You’ve probably eaten them recently, especially if you like Asian food or if you’re on a strict diet.  Mung bean sprouts are the popular white bean sprouts found in every grocery store, and their crisp crunch is a familiar texture in stir-fries, spring rolls and salads. Although they’re native to India, their use is widespread across Asian cuisine.  The beans’ starch is used to make bean thread noodles, and the beans themselves are used to make the paste that fills Chinese mooncakes, or for some kinds of the Indian dish dal (although I’m used to the lentil variety.  Has anyone had mung bean dal—does it taste similar?).

Mung bean sprouts. Fresh, crisp, tasty, and chock-full of nuclease. (Open source photo by Kwantonge).

But mung beans are also a surprising component of every molecular biologist’s toolkit, because they produce a useful enzyme (mung bean nuclease).  There are quite a lot of applications for which this handy tool can be used, but I generally use it for cutting away dangling single-stranded tails of DNA.  A huge, huge part of practical molecular biology is playing cut-and-paste with DNA: I have a piece of DNA over here, and I want to put it into a different piece of DNA over there.  This requires the molecular equivalent of scissors and glue—something that will cut DNA apart, and something else that will glue it back together.  Mung bean nuclease is a very specialized pair of molecular scissors.

Any other favorite uses from the biologists out there?

On my bench: a few precious drops of molecular scissors.

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