Engineered Bacteria Glows To Reveal Land Mines

MikeChino writes "Sifting through minefields to remove hidden threats is a dangerous, tedious, and expensive process. Scientists at the University of Edinburgh recently announced that they have engineered a strain of bacteria that glows green in the presence of explosives, making mine detection a snap. The new strain of bacteria can be sprayed onto local affected areas or air-dropped over entire fields of mines. Within a few hours the bacteria strain begins to glow wherever traces of explosive chemicals are present."

Comments

Pitch

[ExE122]

...making mine detection a snap

I dunno, sounds like a sales pitch to me... you should have either written it in all caps Billy Mays style or said, "Made in Scotland... you know the Scottish make good stuff"

Reguardless, the article has already been /.ed so here are some other sources: Discover, Treehugger, and DNA

Re:Pitch

[OverlordQ]

Your first two links are the same, might have been meant to direct here instead.

Re:Pitch

[reverseengineer]

It looks like the University of Edinburgh entered this project in the International Genetically Engineered Machine competition, so they have a project page with a lot of information. From what I gather, it would appear that the system is based on a system of enzymes that break down soil nitrites which have been linked to Green Fluorescent Protein. Nitrites are a natural byproduct of the breakdown of nitro-based explosives like TNT and PETN. Of course, soil nitrites from non-leaking landmine sources, like chemical fertilizers would also trigger fluorescence, so the team engineered a non-natural gene promoter protein. The genes to produce the fluorescent complex only get transcribed and translated into protein if the promoter is active. The activator for that promoter is a molecule of TNT, so the bacteria will only glow if TNT is present.

I'd also encourage people to take a look at the other iGEM projects. Lots of interesting reading.

Re:Pitch

[Vainglorious Coward]

Afghanistan is the most mined country

Afghanistan comes in 4th according to this source. I was a little surprised that Egypt tops that list.

Re:Pitch

[reverseengineer]

In most soils, there live denitrifying bacteria, whose metabolism is based on reducing oxidized forms of nitrogen, eventually turning it back into nitrogen gas which reenters the atmosphere. These bacteria are recyclers, generally getting on by "unfixing" the fixed forms of nitrogen most other organisms rely on to survive, and so tend not to be picky about their nitrogen sources. They have enzymes called flavoprotein reductases that let them get nitrogen from organic nitrates, like from decaying organic matter. It turns out, however, that these enzymes also let them use many of our most common nitrated chemical explosives as a nitrogen source as well. In fact, one such enzyme has even been named PETN reductase, like the PETN that's in Semtex. I'm saying that if you spray liquid explosive on soil, the bacteria that already live there will eat it like candy. The mines would far outlast the spraying, which is exactly the problem- landmines around the world have far outlasted the conflicts they were laid for in the first place.

The method proposed by this group from Edinburgh actually takes advantage of that process, though. An old landmine or unexploded ordnance is probably going to be slowly leaching explosive out of the weapon. This means that soil near the device will contain the explosive itself, and also nitrites, which are produced as an intermediate step of breaking down the explosive material.

The group set up a sort of two-factor authorization. They genetically engineered promoters, proteins that bind to DNA and promote transcription of a particular genetic sequence, for two fluorescent proteins. Nitrite ion binds to the promoter for luxAB.GFP, which is a fusion protein of bacterial luciferase and green fluorescent protein. Thus, whenever nitrites are present, this protein gets made, and the bacterium glows a pleasing blue-green color. Not just fluoresces, mind you, but actively puts out light, due to the luciferase part. There is another sequence, for enhanced yellow fluorescent protein (eyfp). That promoter is activated by the presence of trinitrotoluene; the group used computational methods to develop a protein that binds DNA if it is also bound to TNT. Unlike the luxAB.GFP fusion protein, eyfp only fluoresces. It will glow yellow only if higher energy light has been input. So if pure TNT were present, the bacterium would make eyfp, but would only glow under UV light. When only nitrites are present, it actively glows blue. When both are present, the luxAB.GFP dumps light on eyfp, and the bacteria actively glow yellow. And then you call the bomb squad.

Nice idea, but...

[TrentTheThief]

Exploded mines and artillery shells leave unburnt residue.

Re:The hills are alive...

[John Hasler]

> The hills are alive...

True. Topsoil is several percent bacteria by weight.

> What assurances do we have that the bacteria won't mutate, self-replicate, or
> turn against its master in the form of some horrendous new super-bug that
> makes the 20,000 land-mine casualties a year seem like a drop in a bucket?

None. And the sames goes for the millions of other species of bacteria that infest every square meter of the Earth's surface.

Re:I don't think you comprehend the problem

[dontmakemethink]

I wouldn't say that they're "past" mines, if anything they lack the resources and facilities to make a proper mine, instead what they make are called Improvised Explosive Devices (IED's) which can perform the job of a mine, but can't withstand the elements for decades like a properly encased munition mine can. Sure, many are triggered manually, but a pressure plate trigger can be made from the ringer out of a typical telephone - a piezo transducer, same thing used to measure earthquakes. Wire that through a relay to a diesel-nitrogen cocktail, and it'll take the treads off a tank no problem, but it couldn't last more than maybe 5 years before the batteries die.

Take a look at the tanks and APV junkyards in Afghanistan and try telling the repair crews there aren't any mines out there. And there are definitely booby traps in buildings where the bacteria could come in handy for sure.

Re:I don't think you comprehend the problem

[coolsnowmen]

Modern warfare by insurgents is ALREADY past mines, since they don't have an endless amount of money to spend - they already place explosives and use remote detonators when troops come by.

What you've said is not true. I said this to someone else, and at the risk of being modded redundant- BOTH triggers are used in Afghanistan against US troops. Remote detonation falls to the age-old electronic counter measure and it's best defense is a higher power jamer. This is compounded by the fact that the cheapest way to remote detonate is with cellphones, which only operate over a limited & known range of frequencies. Because of this flaw other types of triggers (force/pressure based) are still used (and because for pressure based explosions no enemy has to be physically present ['set it and forget it']).
(I work in land mine detection)