Monday, April 18, 2011

It's monday!

Which means the National hasn't done anything to piss me off and Labour hasn't done anything to make me horribly depressed yet. So, I get to rattle on about some cool biology. Though I'm not entirely sure whether this is classed as physics or biology. Every so often, you'll see some actual reporting in the tabloids when we get an outbreak of MRSA at a hospital. Or as they prefer to call it "superbugs". MRSA is short for Methicillin-resistant Staphylococcus aureus. S. aureus is a nasty bug which can cause anything from acne through to pneumonia, meningitis or toxic shock syndrome.

For years, it was easy to fight of with penicillin. The cell walls of bacteria are made up of lipids. Lipids, being molecules with hydrophobic tails form a single membrane by creating an two interlocking layers of themselves, which hides the tails on the inside. Penicillin binds to a protein in the bacteria which assembles this interlocking layer. And when a bacteria can't construct/fix it's walls it does. The introduction, overuse and improper use of penicillin led to a bit of an arms race, with some bacteria producing enzymes which cut the piece of penicillin that binds to the bacterial protein, letting it continue working. Various other anti-biotics have been made over the years, targeting various parts of the bacteria but eventually, there is usually a strain of bacteria that finds it's way around the mechanisms. MRSA is a strain of S. aureus that has found it's way around almost everything we've been able to throw at it.

Rather than targeting the internal workings of cells, the next plan of attack has been to used charged peptides that directly attack and cut the membrane leading to bacterial doom. There are problems with this approach, expense for one, specificity for another (making sure the charged peptides hit only bad bacteria, not other cells). Last week, Ars Technica brought me news of a paper in Nature Chemistry by Nederburg et al. They have made some biodegradable nanoparticle thing-a-ma-bobs which happily enter the body and target gram positive bacteria, including MRSA and some nasty fungi as well. The particles degrade into alcohol and CO2 leaving the red blood cells and the like alone. In mice at least. As always, there's probably a while to go before any testing in humans, but still.

I leave you all to ponder exactly how cool this is. Hint: If you don't include the word very, you're wrong.

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