I had a fun day yesterday doing the "C. elegans" practical, which is part of the first-year labs. In the practical, we got to look at live C. elegans and also set up some PCR reactions to genotype some wild-type and mutant C. elegans. It was all fun stuff.
Below is a movie we shot of the worms on the day of the practical and some stills from the microscopes.
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Last week we had our annual first-year 'paramecium practical'. The aims of the session were to familiarise the students with the microscopes and to also introduce unicellular organisms.
In the UK we order the paramecium for the practical from a local supplier. However, in Malaysia, despite 4 months of searching, I was unable to find a supplier. This left me with three options:
I tried to find an alternative supplier (paramecium are used to feed baby fish), but none of the local pet stores stocked them - although I did get a rather nice bag of water fleas (Daphnia).
A bag of Water Flea - Daphnia
A Water Flea - Daphnia
Finally, I decided to culture them.
After a quick read around the Internet, I found a recipe for culture media and some advice on where to find paramecium.
The general advice for 'hunting' paramecium is to take water from close to the top or the edge of a pond. In the end, I took a sample of water from the surface, plus some material from the bottom of the pond. This was allowed to settle overnight (see photo below).
The culture media consisted of dog biscuits, and 4 or 5 cm2 of lettuce leaf, in water.
Dog Biscuits
Lettuce Leaf
Water
Pond Water - a mixture of material from the bottom of the pond, and water from the surface and edge
Two culture bottles and a bottle of bond water
I set up three bottles, two culture media, and a bottle of pond water. These were left overnight.
And the next morning… The pond water had cleared, and the bottles with dog biscuits and lettuce were cloudy (the cloudiness was caused by bacteria growing) - these will be a food source for the paramecium.
One of the 'culture media' bottles was seeded with 20 ml of water from the top of the pond bottle, and the other with 20 ml of water collected near the vegetation at the bottom of the pond bottle.
Next morning - the three bottles…..
An examination of the pond water under a microscope revealed the presence of paramecium, but not that many.
There were also some other ciliates present…
Over the next 12 days, the cultures got progressively more cloudy and exceedingly smelly.
12 days after adding the pond water
Of the two culture bottles, the one seeded with water from the top of the pond bottle produced the best (most and largest) paramecium, and the best place to harvest the paramecium was from the top 5 - 10 mm of the bottle, and in particular the layer of 'scum' that had formed on the top of the water. Paramecium taken from elsewhere in the bottle tended to be smaller.
Movie
The movie below was shot during the practical.
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In Malaysia, I am called Dr Nick.... And I couldn't understand why... Today, I found out.
In Malaysia, there are no family names, as in Morris, Smith, Jones etc. Your last name is your father's first name, so if my father's first name was Ian, then I would be Nick Ian. Hence, as I am Dr Nick Morris, this suggests that my father's first name was Morris, and Dr Morris would be my father!
This can get odd for a woman, as they would be Julie Ian, and so would Ms Ian if the European convention was followed.
Thanks to The Simpsons, Dr. Nick has a certain 'feeling' about it. You can read more about Dr. Nick of Simpson's fame on Wikipedia.
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Great to finally see a paper that I was working on last year out in print….
Liu,Y., Turdi,S., Park,T., Morris,N.J., Deshaies,Y., Xu,A. & Sweeney,G. Adiponectin corrects high fat diet-induced disturbances in muscle metabolomic profile and whole body glucose homeostasis (2013) Diabetes 62 743-752
Pubmed Link: http://www.ncbi.nlm.nih.gov/pubmed/23238294
There is also a very nice commentary (subscription required) at: http://diabetes.diabetesjournals.org/content/62/3/701.full
The others did all the hard work; I just applied my geeky computing skills to crunch and analyse all the lovely data that was produced. Happy days!
This one causes students problems every year - the relationship between Glycogen Synthase Kinase 3 (GSK3) and Glycogen Synthase (GS), and their phosphorylation states and activity.
If you look at insulin signalling overall:
You will see that activated protein kinase B (activated by phosphorylation) phosphorylates and inactivates GSK3. This means that GSK3 can no longer phosphorylate its substrate, GS.
Now, GS, when phosphorylated, is inactive. Hence, as GSK3 is no longer active (as it is phosphorylated) it cannot phosphorylate GS and inactivate it, therefore GS remains un-phosphorylated and therefore active so it can make glycogen.
The key to understanding this is that phosphorylated (inactive) and un-phosphorylated (active) forms of GS are in a state of equilibrium and that the kinase, GSK3, drives the equilibrium to the right (inactive) in the figure below, whereas the phosphatase (which removes the phosphate) drives the equilibrium to the left (active). Therefore, if you inhibit the action of the kinase (GSK3) the net result is more un-phosphorylated GS, hence more glycogen is made, which is just what we want…
One key thing to keep in mind is that the phosphorylation of a protein can cause it to become active or inactive. It all depends on the protein.
If you would like to support my blogging efforts, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm
If you would like to support my blogging efforts, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm
The movie below shows the 3d structure of a guanosine diphosphate (GDP) bound G protein alpha-subunit.
The small green molecule in the middle is the bound GDP.
https://www.rcsb.org/structure/1TAG
If you would like to support my blogging efforts, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm
