Field of Science

Guarding Microbial diversity - SGM series

This is the first of the Spring 2011 SGM series; where I steal random topics from the Society for General Microbiology Spring Conference and write about them in my blog. It should be noted that I am in no way affiliated to the Society, I'm just currently not rich or scientific enough to go to their conferences. (next year...)

I was quite intrigued when I saw this topic, as microbial diversity has always seemed to me to be a little bit like rats. Interesting to the people that study them, irritating and potentially hazardous to those who don't, but not really in need of any special protection. Bacteria evolve quickly, and share DNA easily, forming many, many diverse species capable of occupying a wide variety of niches.

However while bacteria are indeed very diverse and happy to remain so, the challenge comes in cataloguing all of that diversity. New bacteria need to be examined, named, placed in a taxonomic group, and preferably stored so that if anyone has a particular urge to work on (say) a specific type of hydrogen-eating swamp bacteria, they can find a sample of it and do that work.

What I hadn't realised was that there are quite a few places that are designed to store bacterial cultures. One such place is the DSMZ collection in Germany which boasts over 20,000 cultures of assorted microorganisms. These are stored as dried samples, not alive yet easily able to resuscitate. For a small fee, you can order a sample from them, together with instructions as to how to bring it back to life and culture it within a laboratory. Without storage facilities such as these, it's easy to see how interesting new bacteria would simply get lost, due to freezer melt-downs in labs, or people discarding the wrong samples.

It's not just the finding and the storing of bacteria that are vital in order to maintain scientific knowledge of their diversity, you've also got to name the things. After all, an unlabelled catalogue is no use at all. And with the name comes characterisation - a whole list of the properties and behaviour of the bacteria down to as much biochemical information as is feasible. The speed and accuracy of full-genome sequencing does make this a lot easier, but there are still many properties that depend on more than just the genes. A bacterium might possess the gene for (say) iron metabolism, but that doesn't mean it uses it all the time, or indeed at all. Knowing the genome sequence also makes it a lot easier to quickly place a bacterium into an existing group or species. Although bacteria do share DNA between each other, recently acquired DNA can usually be distinguished from the core genes that mark the species.

UK strains can be acquired through the Health Protection Agency, which is an aggregation of four previously separate culture collections. The bacterial arm of it has around 5000 different bacterial cultures. I did do a quick check as to whether I could get a small sample of S. erythraea using my Debit Card, but you need to be officially registered before they start handing out the bacteria!

It's quite strange to think that these talks are actually taking place up in the north of the country while I'm writing this. Next year though, I'm aiming not just to turn up, but actually bring a poster with me, to show off some of my own work.

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