DAy FOUR!

Today, we finally get to do something challenging and fun - dissecting a drosophila larva to get its polytene chromosome.

This is our first time dissecting a larva after observing them for days and not doing anything. It seemed gross and scary at first, as when we first saw the bottle full of maggots, it was quite an unpleasant sight. But, we soon overcame it, and got to our task.

the first challenge that we meet was the minute size of the maggot. We were required to find a fat maggot, but all we found were small and scrawn ones (if that fits the description). We had no choice but to use those.

What we were supposed to do was to dissect the larva. A moving and living larva. First we put a drop of saline onto a glass slip, which was used to provide a moist environment for the unlucky larva. Then we proceeded on to dissecting the larva. We had to pierce the larva's head using a needle to keep it in position, then use a pair of forceps to pull the larva apart. Sounds terrific? Can you imagine how painful it is?!

Dissecting the insect proved to be a messy job. On my first try, I actually bursted the head of the insect, leaving a globule of mess at the head. At first I thought it was dead, but under the microscope, you can actually see that it was not dead! The mouth was still chomping away but its head was a gone case. Well, that was a failed attempt.

I tried again to dissect a larva, but it was so difficult! Either i smashed the head, or i messed up the salivary glands in the larva. After attempting for sooooo many times, i finally got something, 2 salivary glands with the rest of the mess sticking around it. I tried getting rid of the rest of the body by tapping the saline, but I ended poking the salivary glands itself, destroying it. SO here i go again, trying to dissect another larva.

On the last attempt, i managed to get a salivary gland seperated from the rest of the body parts, and i went to replace the saline with hydrochloric acid, whic serves to rupture the cell membrane to release the chromosome. Then i went to stain the chromosome with Aceto-Oreic Stain or 10 minutes. Finally, i replaced the stain with Acetic Acid to make the stain permanent.
Then i looked at the product under the microscope again. It was kind of sad when i did not get the chromosomes but a bunch of messup stains. But like wht Ms Sandy said, it is the process that counts. At least we tried our best!

Anyways, i think i killed at least 20maggots. Sorry maggots! ):