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Rough Science 2 Carriacou: Mike Leahy's diary: Bugs and barometers

Updated Monday, 28th January 2008

Making an antibacterial cream might be easier if Mike Leahy wasn't being attacked by so many bugs.

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Day 1

I'm pretty positive. We are given the challenges. At last I can use science that I have some experience in.

OK, I'm a virologist not a microbiologist but I do use bacteria as 'tools' and am comfortable with the techniques used when growing them. My challenge, together with Ellen, was to make an anti-bacterial cream. The first task was to grow bacteria. That would be difficult enough without even thinking about stopping them grow.

Just to clarify a point - although in the TV programme we say anti-bacterial or bacteriocidal. The test we plan to use will only identify bacteriastatic agents - in other words, those that prevent bacteria from growing rather than those that kill them.

Day 2

I got to the factory to check the bacteria - didn't look like they had grown very well. Bummer! The bottle didn't smell at all. This wasn't a good sign. The day hadn't started well either because I was covered with bites around the back of my legs and butt. Even so, I fuelled up the autoclave and sterilised the plates we would use to hold the agar.

An autoclave is like a pressure cooker. It allows a saucepan to operate under pressure when heated. This raises the boiling temperature of water. If the pressure is raised to 15lbs per square inch water boils at 121°C. This was the only fact I knew - a weird imperial/metric mixture. With Kathy I worked out that using a 75mm diameter tin I could add a 17kg weight to raise pressure to allow a boiling temperature of 107°C or, if I could find a 50kg weight I could get a boiling temperature of 121°C. This would be difficult - imagine balancing a teenager on a can of baked beans. If we had used a slightly bigger tin (because area increases as a square) we would have had to balance a car or a couple of cows on a can about 15cm diameter. In the end we found a lump of concrete which certainly didn't weigh 50kg but was definitely more than 17kg. Therefore, we guessed that we were getting a boiling temperature of around 110°C-112°C. It looked pretty ungainly.

Around lunchtime we had a crisis with the agar and burnt some while trying to film. Ellen and I then struggled on with the next batch which, luckily, worked very well. It was all very hectic.

Day 3

This was day three of the challenge and Ellen and I were well ahead of the game - but only if things worked. If no bacteria had grown overnight we would be stuffed. Steve was concerned - it would have been nice if the bigger projects worked well all the time but they were all quite difficult.

We finally arrived at the lime factory and had a look - not the smartest plates in the world but there was definitely plenty of bacteria. We had real trouble spreading them with the tools available and because it was so hot the agar wasn't setting quite as well as we had hoped the previous day so we weren't expecting perfect results. We would have been happy with any bacteria and we had loads. We would have been even happier if we could see an effect of the bacteriacidal (or more correctly bacteriastatic) agents. Luckily the garlic worked wonderfully. Of course, the plates weren't as nice as they would be in a lab but at least we had a good idea of what we wanted to add to the tests. But...

1. We were not familiar with the seaweed on the island and as they aren't plants anyway it wasn't really Ellen's department. Next time we could try different species.
2. If the agar were no better, regardless of species, we could have chilled it to make it more solid when we originally manipulated it.
3. A more precise spreader would have made the plates more uniform, but glass blowing/melting was difficult.
4. The media could have been optimised. It was very hit and miss.
5. To get a more defined area of inhibition we could have let the bacterial inoculum 'soak in' or dry a little before adding the anti-bacterial agent.
6. Most important, we could have made titrations/diluted the bacteria or anti-microbial.

The overriding problems were related to our working environment. Labs are air conditioned, for example, but here the temperature varied from 27°C to 34°C and humidity was sky high. At least the incubation time was about right without the need for an accurately regulated incubator. But wind and dust were problems and it was very difficult to keep things clean.

In addition to the microbiology project, a big one in itself, I also had to predict weather using local weather lore. I was worried about this because much of it was bullshit and I had no idea what tropical weather was likely to be and how to predict it. After chatting to local sailors and fishermen I found out that it was unpredictable and you could only really work out weather about two hours ahead if you were lucky. Of course, this excludes the relatively reliable wet and dry seasons. Apart from telling the temperature using a cricket, I just took the opportunity to illustrate chaos theory and point out how difficult it is to predict the weather.

As we approached the end of Programme 2 we were all very tired but keen as mustard. I wanted to finish early - no chance!

Rest day 1

We return to the mangrove swamp and see a steel band.

I laid in with a hangover. Finally emerged around 10 o'clock ready to leave. I had wanted to show J the swamps because otherwise, due to the filming schedule, he would not see them. In the end, Kathy and Angie came along and David offered to drive. We more-or-less re-traced our steps but this time it was far more relaxed. We also had time to climb across the mangrove roots which were amazingly strong. This was probably because they are arch shaped. We chilled for a while before returning to have a good sleep. That night a steel band played at the hotel. It was awesome and most of us danced 'til we dropped. Shell, Amocco and Texaco.

Rest day 2

Another great day off.

Kathy sorted out a sailing boat for those who were going back home during the break. I just did some e-mails and chilled. Filming for 3 days genuinely makes me very tired.





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