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Broken sleep land

I totally didn't make it to the boathouse this morning. I'm pretty sure that I needed those extra 2.5 hours of sleep on C's office floor instead. Especially given how physically painful it felt to get up again at 7 am (more painful than the 3:30 wake-up to ride over to the lab).

Our current stable isotope tracer for characterizing lipid metabolism is not ideal. Apparently L started out trying palmitic acid in the beginning. That's the same lipid tracer as I used in Nebraska, though I used a radiotracer, not a stable isotope tracer. He was never able to obtain a reproducible signal with palmitic acid, so eventually they triangulated on oleic acid instead, injecting a bolus of pure oleic acid with a single C-13 label on the carbon that's easiest to label. A quick check of my notes about my palmitic acid experiences confirm why L never got any signal - only around 1% of the injected radiolabeled palmitate ever got oxidized over a 3-hour time period.

There are a couple of problems with the 1-13C oleic acid. The biggest one is that the amount of oleic acid we're injecting is equivalent to the total amount of lipid present in the entire cricket hemolymph pool. Hardly a tracer, unless there's incredibly high hemolymph lipid turnover. Along with that, as I'm doing the injections, I've observed a couple of crickets that have apparently bled heavily sometime during the 60-minute incubation period, and I'm not entirely sure about what's going on there. I haven't seen nearly as much bleeding during the injections themselves as compared to the glucose injections, but it still seems like there's something strange going on.

Uniformly-labeled C-13 oleic acid should generate a stronger signal, but it's also expensive. I would also need to think about the best injection vehicle for to dilute out this nonpolar compound.

We shall see what the preliminary samples reveal. They have just reached our collaborator today.



( 3 remarks — Remark )
Aug. 25th, 2016 03:05 am (UTC)
It seems like a radiotracer makes everything so very much easier, doesn't it? Mostly because you can non-destructively assay everything?
Aug. 25th, 2016 04:14 am (UTC)
For applications like this, absolutely. It's just that scintillation counters are so darned expensive.
Aug. 25th, 2016 04:37 am (UTC)
There is that.
( 3 remarks — Remark )

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