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18 September 2004 @ 05:41 pm
I've been needlessly cranky all week - probably just coz I'm overtired. As a result I've been thinking of bitchily inappropriate things to say to people, and getting overly wound up by those who merely suffer from minor personality defects rather than saving it for the truly annoying ;) I think I managed not to actually say any of said things to the person they were directed at (though the temptation to post a few passive-aggressive posts about passive-aggressive posts was quite high :P), except the once ... at least it wasn't all that bad. I had a late morning coffee with my colleague Dylan on Thursday, and after complaining about something else I said "And some fucking muppet took the last aliquot of 1kb ladder without making more up so I've got sort that out too!". Cue Dylan looking shifty and saying "Umm, I think that might've been me". Oops ;)

Probably not going to go out to Sonic Flower tonight, though I feel faintly guilty coz Danny & Kerry often ask if we're gonna be going and we're so often not ... but given how tired I was last night (barely keeping my eyes open by 11pm) it's probably not wise. We may head down to the Dove for a drink instead, which seems to be taking over as favourite pub as it's closer than the Fat Cat but still serves proper beer.
Current Mood: crankycranky
Current Music: The Libertines, "The Babyshambles Sessions"
J: {interested}rethought on September 18th, 2004 09:45 am (UTC)
I have to ask, because I read it three times and don't understand...

What is an aliquot of 1kb ladder?

If you have a moment...
Margaretpling on September 18th, 2004 10:05 am (UTC)
Yeah, work jargon. Umm, how to explain ... To visualise DNA we make up a slab of solidish sugar called a gel (agarose, not the sort of sugar one eats) then use an electric current to make the DNA move through the gel - smaller DNA molecules move through quicker than bigger ones, so you end up with a series of bands of different sizes of DNA in the gel. So that you can tell what size the DNA you're looking at is you also put some DNA of known sizes next to it, then you can line your sample up with them. The sample of known sizes is normally known as a 'ladder' (as you get lots of horizontal bands of DNA like rungs of a ladder), and ladders are commercially available in different sizes - the one we use most is a 1kb ladder. (See a picture of a gel here, the ladder is on the left, though it isn't a 1kb one, and the samples are the other 4 lanes (vertical strips))

DNA sizes are measured in number of bases - these can be thought of as positions along the DNA molecule. A 1kb ladder is one which has DNA molecules between 500 bases and 10,000 bases, mostly at 1,000 base intervals - 1 kilobase.

When you buy a tube of 1kb ladder you need to dilute it to the working concentration (always the same, for convenience) and rather than store it in one big tube which might all get lost or contaminated at once it is split into 10 equal amounts in seperate tubes - these are called 'aliquots'. Generally we keep it frozen, but the 'in use' aliquot is in the fridge. Professional courtesy suggests that if you move the last aliquot from the freezer to the fridge then you are the person who should dilute and aliquot the next stock.

And that's what Dylan hadn't done, and I discovered when there was only just enough left for me to use, but not enough for anyone else.

Probably a lot more information than you wanted, but I wasn't sure where to start from so I went right back to basics (I hope).
Jrethought on September 18th, 2004 10:30 am (UTC)
Ah, no...it's quite interesting. I toyed with the idea of going into genetics back when I was a Pre-Med. But, that was long ago. :)