Question: How long does it take to complete your experiments?


  1. šŸ™‚ i had this question durin the chat session! Can’t remember if it was you or someone else

    Examples of what I do and time it takes:

    1. I inject a virus into the brain of mice: 1 hour per mouse
    It takes an hour per mouse from putting them to sleep, doing the surgery and stitching them up (they get painkillers). I usually do 6 mice a day, takes me a whole day.

    2. Diet experiments: 12-26 weeks
    We have put mice on those special high fat diets with or without the pill for 12 to 26 weeks. Every week, we weight them.

    3. Dissecting a mouse: 10 minutes per mouse
    After the mouse is deeply asleep, we take out some blood, the liver, kidneys, pancreas, fat tissue and the brain. We often do about 10-15 mice at a time. More than that is too exhausting!

    4. Protein assay: 30-40 minutes
    Once we have the organs collected, we extract protein from the tissue by adding a buffer that breaks up all the cell membranes. We spin it down in a centrifuge and the cell membrane and nucleus will end up at the bottom of the tube, while the proteins will be floating in the buffer. We take a small sample of this, add 2 chemicals which will turn your protein sample blue. You then put it in the machine (spectrophotometer) and it will tell you how much protein you have in your sample (how blue it is). You need to also make standards, where you know exactly how much protein you have and how blue it is.

    5. Western blotting: 2 full days!
    I did one on Wednesday and Thursday. You make a gel. Into the gel, you inject/pipette your protein samples. You then put the gel inside a chamber filled with buffer. You then turn on the power and ‘run’ the gel for 2 hours. Proteins are negatively charged, so within the gel, they will migrate towards the positve pole. Also, the gel itself has small pores, so smaller proteins will travel faster than the bigger proteins. When the gel is finished running, we transfer the proteins that have been separated in the gel onto a thin membrane (takes another 1.5 hours). After the transfer, we block the membranes in a buffer with milk powder (1 hour) and then incubate the membranes overnight in a buffer with an antibody. The antibody will attach to your protein of interest! The next day, you have to wash your membrane several times, and incubate it with a checical that will make the antibody attached to your protein of interest glow! Then, you put it in a machine which can detect the glow and you get a picture of your proteins! It’s all on wikipedia under SDS-PAGE if you’re interested

    6. Preparing tissue sections for staining: several days……
    You collect the organ of interest from your mouse. You then put it in formalin for 24 hours which will fix the tissue! This way, it can’t rot and the structure of the cell will look like it did when it was still alive….
    Then, you change the formalin to 70% ethanol. Then, we put the organ in a small cassette and bring it to the pathology department of St Vincents hospital (next door). They will then take several days to ’embed’ the tissue in a block of paraffin (like candle wax). You need this to be able to cut your tissue in thin sections. Once we collect the organs in paraffin blocks, we can cut it!
    We use a machine called a microtome which can cut sections as thin as 3 micrometers! Cutting one section will take you maybe a minutes, but if you need more tissue sections or have to take a section from many different mice, it could take you hours…..

    7. Staining a tissue section: 1-5 hours
    Once you have your thin section of tissue on a glass slide, we bake it in an oven for 1 hour, to make sure it really sticks to the glass slide. Then, we put it in a xylene bath for 5 minutes, which will dissolve the paraffin and fats. Then we rehyrdate the tissue by putting it into 100% ethanol for 4 minutes, 95% ethanol for 1 minute, 70% ethanol for 1 minute and then water for 1 minute. After this step, we can stain the tissue. For simple stains (just to look at the structure of tissue), it takes no more than 30 minutes to and hour. A child could do it! For stainings where you want to stain a protein of interest, it will take several hours!

    Other things I do
    Gene expression studies: collect organ/tissue 10 minutes, extract RNA 1 hour, make into cDNA 1 hour, prepare the gene expression study plate 2 hours, running the PCR reaction 2 hours, analysis of data 1 hour

    Cell culture: changing the medium (=buffer with all nutrients cells need) in the culture dishes where I have cells growing with new medium 10 minutes

    Doing a blood glucose test on mice: 2 hours (take a small blood sample at time 0 to measure blood glucose level, then inject with glucose, measure glucose levels again at 15, 30, 60, 90 and 120 minutes. This will tell you if your mouse is healthy with good glucose control or diabetic.)

    Making the high fat diet: 20 minutes (we combine flour, bran, sugar, vitamin powder, mineral powder with 2 packs of melted lard and a bit of safflower oil, kneed it into a dough)

    2. Protein assay:


  2. I don’t do experiments in the way that Natasha does; I’m a theoretical biologist, so I use math and reasoning to look for patterns and explanations in evolution and biology in general. Thus, the projects I work can go really quickly (if we’re looking at a simple idea and working it up fast) or they can take a long time to think through, to do the math for, to look for evidence in other published work, and even do computer simulations. Simulations are probably the time consuming things I do, and they can take days, weeks, or months to finish!

    In general, I’d say that my projects take anywhere from a few weeks to a year or more to finish. Sorry I can’t be more specific, but each one is different!