Sunday, August 1, 2010

Five Ways Not to Grow Insect Cells

I'm kind of afraid Sarah will sneak into my room at night and shave my eyebrows off if I don't post...so here it goes.

I (along with most of the other contributors to this wonderful blog) have recently successfully completed the Hughes Program. After working in our labs every day, all day for ten weeks we're finally done with our projects. Or at least that was the idea. I am nowhere near done with my project.

Swastik, my lab's awesome grad student (I, too, am not a part of the MacQueen lab), told me the other day that when Thomas Edison finally succeeded in making the light bulb after his 30th attempt (or something like that), someone asked him if he felt like he was wasting his time for all those years he spent unsuccessfully making the light bulb. Apparently, the wise Mr. Edison replied that he did not, in fact, feel as though he had wasted his time because he now knew of 29 ways not to make a light bulb.

Well, I've spent the last 10 weeks growing insect cells, and I've learned at least 5 ways not to grow insect cells. I'm using insect cells as a way to express a eukaryotic protein and make a lot of it in hopes of one day crystallizing it and finding its structure. The cells I'm using are ovarian cells from this caterpillar, called the cabbage loper (Trichoplusia ni):

Because they're just the ovarian cells, they don't have any kind of immune system, so they have to be cultured with sterile technique. This means I have to work with them inside a sterile hood, spray everything that goes into the hood (including my hands and arms) with ethanol and generally make sure I don't contaminate them. If they die, then I have to start over from a frozen stock.
In order to make them express my protein, I infect them with a virus called baculovirus. In the wild, I'm told this virus causes the caterpillars to burst and drip down onto the caterpillars on tree branches below them, infecting these caterpillars as well. In the lab, we use a virus that has the instructions for making our protein in it, so before it kills the cells, it causes them to make a bunch of protein.
Anyway, I'm the first student in my lab (the Olson lab) to use this expression system, as we, like the MacQueen lab, just started last fall. Therefore, it's been kind of an adventure for me to figure out what to do and not to do, and while I did manage to express enough protein to squeeze out some data this summer, I also discovered at least five ways NOT to grow insect cells. Because I did not have a chance to share this accomplishment on my Hughes poster, I will take the opportunity to do so here.

Five Ways Not to Grow Insect Cells by Falcon Tube:
Don't grow insect cells by...
1) ...Letting them get too hot. This is tricky if you're working somewhere where they keep turing off the AC when it gets above 95 outside (as they do at Wesleyan).
2) ...Being too obsessed and look at them every day twice a day, as you'll shake them around too much and they'll die, or at least be unhappy and grow slowly.
3) ...Growing them without antibiotics. They can get infected with bacteria and die. (Some people do actually grow them without antibiotics, but it didn't work for me).
4) ...Letting them get infected with fungus. They will die. (There's nothing you can really do about this except being extra sterile).
5) ...Letting all of your cells get infected with your virus. All of them will make your protein...but then they'll die. This makes it a) impossible to have negative controls b) really hard to get anything done.

So now I know all of these things can happen to insect cells. And I know (at least a little bit better) how to stop them from happening. I'm proud to say I've had happy, living insect cells for about two or three weeks now, and I hope to keep them that way for a productive semester.

Photo credit: http://blog.ecosmart.com/index.php/2009/07/31/cabbage-looper-control/

Tuesday, July 27, 2010

Now We Can Be Bffls!

I was told by Sarah that if I did not write on the blog of the esteemed MacQueen lab, we could not be best friends. Therefore, I must post!

A few members of the MacQueen lab tentatively came into the Hingorani lab the other day to look at my microplates. In the microplates were fabulous colors (whose beauty was magnified by the photography skills of the MacQueen gang--see 'Sourjourn into Manjuland").

I am working on characterizing the kinetics of three MutS (Msh2-Msh6 in humans) mutants. MutS is a protein that recognizes mismatched DNA and recruits other proteins to initiate the DNA mismatch repair process. I am studying three cancer-associated mutants in Thermus aquaticus ("Taq"), as it is an easy organism to work with and there is high sequence homology between Taq and human MutS. In addition to binding mismatched DNA, MutS it is also an ATPase, and we're interested in the mechanism of ATP hydrolysis (ATP--> ADP + Pi) in the MutS mutants, and it is thought that MutS may communicate that it has bound a mismatch through coordination of its DNA binding site and ATPase domain.

One way to measure ATP hydrolysis is through phosphate production. The microplates that the MacQueeners photographed were part of the "Malachite Green Assay." Malachite green turns from yellow to green when it binds phosphate and this color change can be quantified. We create a standard curve with our stock of phosphate and then use this standard to calculate the concentration of phosphate at different time points in the reaction mixture that includes MutS and ATP. Using the concentration of phosphate at different time points in the reaction, we are able to determine kcat, which informs us about how fast the protein hydrolyzes ATP (more formally, kcat represents how many molecules of ATP are hydrolyzed per MutS active site per minute).

So there we go. Those are the pretty colors.

Sarah, now can we be best friends?

Saturday, July 24, 2010

On WEAST- Edit

So I would like to edit my previous post. I neglected to mention some important information; the other labs that present at the WEAST meeting are the wonderful Holmes lab, with whom we went on a hike and you will hopefully see pictures soon, and the fabulous McAlear lab. The other person presentin today (bc more than one person usually presents at WEAST) was Sarah Kass-Gergi, a brilliant undergrad from the McAlear lab. Hopefully we can convince her to write a post sometime in the future.

Sojourns in Manjuland

Today, something very special happened.

We got to visit Manju's lab.

Let me give some background information so as to explain wh
y THIS IS A HUGE DEAL. Dr. Manju Hingorani runs the lab next door, and I think she is kind of enigmatic, and very awesome. She keeps a little tiny tote bag stocked with chocolate hanging on the doorknob of her office, and she's always pacing around with a canteen of loose tea leaves and whispering about DNA. I'm not so sure the admiration is mu
tual, though, because in the past, Manju (who, by the way, INSISTS that everybody, students included, refer to her as Manju and gave me a death look the first [and last] time I referred to her as Dr. Hingorani) has expressed her, um, dissatisfaction with some of the more robustly-vocal-chorded undergrads of the MacQueen Lab
(one is the author of this post and the other has a nickname that rhymes with "gators")
and their propensity for emitting cackles that reverberate into her office. Given this stormy torrid drama of our past, I always thought setting foot into DNALab would be a mere dream, never to be fulfilled...


BUT NAY!!!!!!!!!!!!!!!!!!

Today after WEAST (which will be blogged about in the near future for those of you not in the know), Tatiana came galloping into our lab proclaiming "ARIEL IS DOING THINGS WITH PRETTY 96-WELL PLATES!!!!!!!!!!!!" Ariel is the awesome undergrad in Manju's lab who, as Esther informed us, placed first in her group in the Middletown 5k!! Anyway, I grabbed my camera and scurried to investigate.




HOW COOL IS THAT?!?!??!?!?!?!?!

More science eye candy:





I know at this point you're probably thinking "Wow, that IS pretty, but what IS it?" (either that or "This girl needs to get out more"), and I am embarrassed to say that in my haste to get back to work (okay, it was actually because Ariel made us leave), I didn't ask her what exactly these were for. But I PROMISE I will find out and update next week because I know you're all as curious as I am!!!!!!!

P.S.: Get excited for a SUPER-SCIENTIFIC (seriously!) post tomorrow about the biochemistry behind SPORULATION! It's one of the most useful and important techniques that we use in our lab, but admit it, do you really know why putting yeast into media containing potassium acetate makes them enter meiosis (beyond "it starves them")? FIND OUT HERE TOMORROW!! (I was actually going to write this post tonight, but then I ended up spending more than an hour JUST ON THE RESEARCH. This is legit, folks!)

On WEAST


Hey y'all! I'm writing a breif entry about our WEAST meeting. Since everyone has been scolding me for not having blogged yet, I figured better a short entry than no entry at all.


Today we had our last WEAST meeting of the summer :(. As sarah would say, sad day. WEAST meetings are these wonderful meetings that we've organized with some of the other labs that use yeast ( hence weast, wes yeast). They are super helpful for learning how to present your material to others, dealing with questions and troubleshooting. I think it is very nice to have meetings with people who know the organism and can bring different perspectives and advice to the table on a particular project.


Since today was our last day of the summer we had tons of food (nom nom). Rozina and I presented the work that we have been doing, which is basically to create a tool, in our case a temperature sensative allele, that will allow us to investigate the role of Zip2, Zip3 and Zip4 in synaptonemal complex, the protein that holds homologs together during Meiosis I. In case you were wondering what the above picture is, it was a drawing I did for our presentation of abnormal and normal synaptonemal complex.
I think the presentation went more or less smoothly, there were a couple of questions that I had some difficulty with but overall it was a great learning experience. We have presented our work a few times now and each time we learn something new about how to present, or the content itself. I hope that WEAST will be able to continue into the year and I think that it's the kind of meeting that all labs should be doing in their field on a regular basis because it promotes sharing of information, ideas and thereby progress and forward momentum

Friday, July 23, 2010

Things that need to be addressed...

Firstly:
Nicki Minaj > Lady Gaga
(greater than)

Secondly:
weekend project?

Thirdly:
Sarah, are you a giant puddle of red goo yet?

I HAS IT

seeing as to that I'm on "vacation" I'm going to troll this blog n not put science related things up, until next week of course