Debbie Knight

Archive for March, 2013|Monthly archive page

Photo of the Week

In lab safety, photo log on March 19, 2013 at 9:00 am



I was in my old stomping grounds — a building where my lab had been located some ten years ago.

I wasn’t looking for it, but I found this safety sign I had made (and posted).

Still there.

In the safety shower area.

The reason I put up this sign was that the nearby labs used this space to stash their cart. Now, I will admit, if this weren’t a designated safety shower, it would’ve made a great place to store a cart. However, if you are on fire or have some chemical burning your eyes, the last thing you’d want to do is take the time to shove a cart out of the way before dousing yourself in water.

Hence the sign.

I’m amazed it’s still there.

D’oh! Moment #429

In observation on March 14, 2013 at 11:32 am


This illustration I found on PhD Jokes’ Facebook page made me laugh because it’s so true!

I can’t tell you how many times this has happened to me. You have your 8-channel (or even a 12-channel) pipet aid, tips loaded and (blam!) one of the tips falls off.

You can carefully tighten down each of the eight tips before dipping them into the solution you are transferring, yet somehow it happens.

You suspect that tiny gremlins are at play because you did, after all, take the time to make sure each tip was secured. There could be “no” other explanation like you bumped the tip on the side of the plate that helped dislodge it. Nope, certainly human error is never a possibility. It must be, without a doubt, gremlins.

Okay, so it’s highly unlikely that the oft blamed creatures are the source of the problem. And even more unlikely that your lab mates or your boss would believe such a tale.

So how to fix such a predicament.

Well, sometimes you get lucky. The tip lands in such a way (like back in the appropriate well or somehow upright) that you can carefully pick it up and “save” the experiment by reattaching the tip.

And … sometimes you can’t.

Sometimes you will have to add a new tip – carefully – without touching any of the others still in place on the pipet aid.

Sometimes you just have to transfer the samples you have and come back, armed with a single pipet tip, and load the lost sample separately.

But there are times, like when you are transferring everything from one well to another  that  by dropping the tip, you’ve managed to lose the entire sample. There’s no coming back from that. Unless … in your infinite wisdom you built in replicate wells into your experiment (i.e., you designed your experiment to have multiple wells testing the same experimental condition).  This is always a wise thing to do.

Another problem that can arise from dropping a tip: when you are transferring infectious or radioactive samples. This is certainly worthy of an expletive or two. You’ve just created a bigger problem. Not only have you possibly lost an experimental condition, but now you will have to decontaminate the working area before you can continue.

Sure, I can laugh at the joke in the illustration above. Now.   While sitting at my computer typing this post. However, it’s not quite so funny when it actually happens during an experiment. And, yes,  I’ve been known to say an expletive or two, sometimes they’re rated G and sometimes not so rated G.

Of course, my most caustic string of expletives will never be a match for one of my lab mates from days long past.

Noelle was the best  at stringing along expletives when experiments go awry.

She sounded a little like the Looney Tunes character, Yosemite Sam.


You could hear her mutter the curses under her breath and it really did sound a lot like “sassafrassin’ raggafrackin’ fillaburgin’ braginstachin’” except they weren’t nearly so tame.

Her rants always made me chuckle.


So as not to further disturb her.

Ah, the good ol’ days.

A Day in the Life: March 7, 2013

In A Day in the Life, research log on March 7, 2013 at 4:56 pm

From time to time, I will give a glimpse into the “glamorous” life of a research associate and talk about what I’m doing in the lab. These entries I will call “A Day in the Life…” 

Today I’m searching for an antibody that I can use to stain the cells that line blood vessels (endothelial cells) in mouse tissue.

And I want to visualize where the antibody binds in that tissue with a dye that glows (or fluoresces) under certain conditions.  Something like this:

MEK14.7 ab8158_3

From Ab8158 at a dilution of 1/50 staining CD34 from mouse lung cells by Immunocytochemistry

A Google search has turned up several results that look promising.

However, there’s some cross checking that has to happen before my lab will plunk down $300 for the antibody. Sure, I could take the company’s word that it works in fluorescent staining techniques, but I need more proof. I need to see that it will work in my experiment and that means finding published images in the scientific literature.

Seeing, after all, is believing.

This process can take time.

For the antibody I’m looking for, there are at least three different versions (or clones).

I’ve spent a couple of hours trying to find just the right one, sifting through the “data.”

The antibody I’ve chosen, clone MEK14.7, seems to work in just about any experimental application. It’s rare to find an antibody that works in fresh samples as well as formalin-fixed samples, but this one does. Why? The molecule the antibody binds to in the tissue (called an antigen) often changes shape when fixed in formalin. The shape determines if the antibody can bind. If it changes, the antibody no longer recognizes (and binds) it.

Now, if I can find this antibody with the right dye on it, life will be good.



If you look at the comments to this post, you will notice that Tom suggested the website 1DegreeBio. com  

I was unaware of this website, but it would have saved me some time in searching for an antibody.

I’m pretty sure I would try it first for any of my antibody searches.

The only thing lacking at this time (and it will improve over time as visitors add their two cents) is there were no ratings/reviews of the antibody reagents I looked at. This would be a big help, although I would caution that if the reviews are done by individual researchers, they should be taken with a grain of salt:  what works well in one researcher’s hands may not in the hands of another.

Why? It could be how the sample was handled before staining with the antibody (such as storage or fixation). It could be the incubation time of the antibody with the tissue — some labs do an overnight incubation in the cold, others (such as myself) incubate an hour or two at room temperature, and some incubate for 30 minutes at body temperature (37 degrees Celsius). These are only two examples, there are several steps in the staining process that could influence the antibody’s performance in an assay. 

Thanks for the suggestion, Tom! 🙂