Laboratory practice makes perfect. Number 112

I didn’t balance the rotor on the new centrifuge correctly last week. A cardinal sin. Possibly the cardinal sin!

Centrifuge Practice: 101

I don’t know if you have ever been in the situation where you have taken your valuable prep up (or down, or across) to the centrifuge room, usually after a very early start. You walk in only to find the dented bodywork of an ultracentrifuge and be greeted with the news that someone has written of thousands of pounds worth of rotor overnight.

It is not a good feeling – plus you have to scurry round trying to find a free centrifuge in some other department, whilst reassuring them that you weren’t responsible for your own ultracentrifuge’s demise. Because, let’s face it, the ultracentrifuge is just about the most useful piece of equipment in the modern Life Sciences laboratory. Just think: pelleting down your cell prep, sucrose gradients, sedimentation equilibrium methods – where would we be without the ultracentrifuge?

This is not to say I like ultracentrifuges – although I do find the smell of the centrifuge room strangely evocative. No, actually ultracentrifuges scare me half to death! I am far too aware of the sheer energy that is locked up within a spinning ultracentrifuge – I do not even like to be in their vicinity. It has been calculated that 1 gram (of anything!) hanging around at the bottom of a SW 60 Ti rotor bucket, spinning at a cool 60,000 rpm exerts the equivalent of half a ton of centrifugal mass at the bottom of the aforementioned bucket! And if that doesn’t give you pause for thought it should do. Who was in there before you, eh? Who just loaded that ultracentrifuge next to yours?

The problem is that people (by which I mean students, so I’m stretching the definition somewhat) are just not taught how to use laboratory equipment properly. Most universities, you leave your course with a detailed knowledge of the Krebs Cycle, but no real idea about making up a molar solution. Laboratory ‘practicals’ so often don’t really teach you anything, well, practical – not for working in a proper laboratory they don’t. Specialised courses maybe, but general Life Science degrees?

Not in my experience, not working with recent graduates or having been one!

I can remember one ‘practical’ I took that was spent drawing a (fresh) pig’s placenta. I labelled it ‘Dead Piggies’. The lecturer was not amused, which probably just shows you that comedy and Zoology are not as compatible as comedian Bill Bailey would have us believe!

My point was, and still is, this: we should be learning stuff in ‘practicals’ that will help us when (and if!) we land a job in a real live laboratory. Stuff like operating an ultracentrifuge correctly, knowing about polyallomer tubes, open-top, optiseal and quick seal; polycarbonate tubes; polypropylene tubes; polyethylene tubes (reusable but not autoclavable) and of course ultra-clear tubes. Stuff like the types of rotor: ‘fixed angle’, ‘swinging bucket’, ‘vertical tube’ and ‘near vertical tube’ and above all stuff like balancing an ultracentrifuge correctly: filling and weighing opposing tubes, checking for detritus and then double-checking if necessary!

It promotes confidence and skill in a way ‘Dead Piggies’ never will. And then last week I didn’t balance my centrifuge correctly.

And what was the result?

Well, both the Polycress and the Mezzula leaves were great (first of the season!) and the walls of my new salad spinner were fine, but it didn’t half bump a bit.

Yes, it was just a salad spinner – but we don’t want to get into bad habits do we?