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Wednesday, 6 April 2016

Taking care of your new pet bacteria

Bacteria have a lot in common with the bigger organisms we all know and love. They need energy, warmth, and all sorts of nutrients in order to grow and live happily. By the way, when talking about bacteria 'grow' normally means 'divide by mitosis to form two daughter bacteria' rather than getting bigger. The great thing about bacteria is, they have adapted to be able to use a huge range of sources of energy and nutrients! Some, like cyanobacteria, harness the power of the sun like plants do. Others live so far underwater that there is no light, so use heat and sulphur and things from deep-sea thermal vents like white-smokers. For food, there are bacteria that can eat pretty much anything; if anything says 'biodegradable', that's just another way of saying 'bacteria can eat me!'

So how do we accommodate these weird and wonderful needs in order to take the bacteria from where they've evolved to live to a much more convenient (for me) laboratory? To be honest for a lot of bacteria we still don't know the answer; only a small proportion are able to be 'cultured', or grown in the lab. We can still find out about the picky ones by sequencing their DNA though, don't worry!

The ones we can grow in the lab do need a bit of looking after. It's a bit like looking after a pet Rabbit! First, you find an enclosure for them; rabbits have hutches, bacteria get petri dishes. Next, they'll need some 'bedding'. Rabbits get hay, which they also like to eat, so in the same way we give the bacteria an agar gel containing nutrients. This gives them a place to grow, and also the food they need! There are a lot of different rabbits but they can mostly be kept fed with the same mix of rabbit food, and once again bacteria are the same. They need a source of carbon, like sugar, some nitrogen, like in ammonia (although some can use it straight from the air), phosphates, and salts. (Of course it's a bit more complicated than that but that's the quick version!) These are all in 'general media' like the well-named 'nutrient agar'. This can then be modified to cater for a particular bacteria or family of bacteria. Some bacteria need to be grown in agar containing blood! Other common things are things like yeast extract, iron or sulphur.

They even look similar! You see it too, right?

Now that they've been fed and housed, we need to work out where to put the rabbit/bacteria. If you put the rabbit hutch in deep shade all winter, you might have some poor frozen bunnies inside. If you put it in full sun over the summer months, they'll start to cook! Bacteria are very similar. Some are happy at room temperature, some need 37 degrees celsius (our body temperature... this is ideal for human pathogens, so I tend to avoid it in my experiments) and some 'thermophiles' like Geobacillus need temperatures around 60 to 80 degrees! I think the highest growth temperature recorded is around 118 degrees (which is crazy! They can survive being boiled!) in some extremophilic bacteria. And archaea too, which is another microbe kingdom like bacteria and fungi. This is pretty easy to control these days though, there are all manner of fancy incubators that can go up to any temperature your pet rabbit bacteria enjoy!

Some don't mind a bit of heat!

That's pretty much it, to be honest. Different bacteria need different things so it's impossible to describe everything in a short blog post but I did my best! Maybe someday soon we'll be seeing bacteria in a cage at the pet shop... There is a microbe zoo in Amsterdam so it's only a matter of time!

I didn't take or make any of these pictures, I'll take them down if I'm not allowed them!

Image sources:$_32.JPG?set_id=880000500F

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