Tuesday, May 31, 2005

science, food, and sex 

lab rant, ignore if not a yeast person

we are having the most annoying fucking problem in the lab. all of a sudden, some of our media plates are JUST NOT WORKING...for no apparent reason.

if you aren't a yeast person, and you're still reading this, let me explain breifly: we use agar plates to grow little yeasty colonies on. we have to add food and nutrients so the yeasties are nice and happy, and by manipulating what nutrients we add to the plates, we can choose which yeasties will grow, and which won't. so if you're only looking to grow yeast that have undergone some mutational rearrangement, or have inserted the little pieces of DNA you tortured the cells into taking up, then you can leave out certain required amino acids, according to what you're looking for. so, for example, if your yeast normally absolutely requires lysine to grow, but you've "transformed," or forced the yeast to take in a piece of DNA, and that DNA has a gene on it that allows your little yeasties to grow WITHOUT lysine, then you can select for the right cells, those that have accepted your DNA, by putting the cells on media plates that lack lysine. we do this by making "drop out" mixes - amino acid mixes that contain ALL but one (or more) amino acids. So, for example, SD-lys = synthetic media containing dextrose and lacking lysine.

SO, anyway, for some odd reason...certain plates just aren't working for us anymore. if we plate a HUGE AMOUNT of cells on them, so that you get a complete "lawn" of yeast, they will grow. but as soon as you dilute the cells, and plate so that normally you would get individual colonies...nothing. zip. nada.

this is FUCKING ANNOYING, since some of our plates work fine (our -lys plates) but other plates...pbbbth! (SD-histidine, and some others). but these plates are made the same way! just different drop out mixes. and making NEW drop out mixes doesn't help.


our lab goddess thinks it's our water filter, but I'm doubtful. if it were, ALL our plates would be affected, not just the SD-his.

so I did a HUGE experiment last week, on around 130 plates...and nothing grew on the SD-histidine. WHAT A WASTE! and it's sporadic...so the next time it might work...and it might not. which means I could be repeating the experiment over and over again, with crappy results. this is driving us insane, and not helping lab moral AT ALL!!!!

food alert! food alert!

tonight for dinner:

grilled salmon fillet marinated in soy sauce, sesame oil, wasabe powder, green onions
teriaki noodles (from a lipton package - I take shortcuts occasionally!)
steamed sugar snap peas with a soy sauce, sesame oil, and sesame seed dressing

oh, and STRONG margaritas! it's a cross cultural extravaganza! god, I'm drunk!

mmmmm...happy tuesday!

if you've made it this far....

Kev worked a looooooong day...but...as soon as he lies down in bed....no sleep for him!


(ESC gets horny when frustrated at work)

just one more thing, ma'am...

knitting pics are up! click on the flickr link on my sidebar.