Tuesday, 17 January 2017

Olivia Chadwick - The Whey to a Larger Mealworm

For my independent investigation i decided to work with the mealworms. I chose to investigate whether whey protein powder would have any effect on the rate of the mealworms growth and if it made them grow any larger than they would have if they had just been eating the porridge oats that they were usually fed.

To do this i put three mealworms in isolation and each day would feed one its usual diet of porridge oats, one whey protein powder and the other a mixture of the two. After a week of them being on these diets i weighed them. As i had expected the mealworm that was fed just the protein powder increased in weight the most however the other two mealworms lost weight, something i wasn't expecting to happen. If i were to do this investigation again i would monitor the mealworms more closely and i would also have more meal worms on each diet and possibly for a longer time as i don't think a week was long enough.

Overall i really enjoyed doing this investigation as it allowed me to increase my knowledge about all of the model organisms at UTC which i have found really interesting.

Friday, 13 January 2017

Tom Buchanan – Year 12

I have very much enjoyed working in the labs so far, I have had the opportunity to work with equipment I would otherwise have never had the chance to use. Such as the spectrophotometer which I have used to measure the absorbance of solution that I have produced in the lab. I enjoyed my microbiology module in which I produced GFP, a protein with the ability to fluoresce under UV light. Perhaps my most favourite so far has been during my enrichment activities were I have had the chance to work with the schools Daphnia Magna, this tiny, interesting organism is visible by the naked eye, however under microscope we are able to examine its transparent body and organs. I have conducted multiple experiments with them, such as monitoring how they respond to environmental changes like pH of their water, it is interesting to see how their new born respond to this change as I have discovered myself that they seem to produce more young when they are exposed to such a big environment change. I could probably go on forever about it. I have learnt key lab skills that are preparing me for a future working in a lab that I hope to one day have. In conclusion, my time so far in the labs has been fantastic, every day is different which is what makes it so exciting. I feel so lucky to be able to have these facilities available to me.

Daphnia on Drugs – Sana Nagi and Muna Ali

Our experiment was to see whether difference substances would affect the heart rate of Daphnia. The resting heart rate of Daphnia was recorded and they were then placed into ethanol, caffeine or water for 10 minutes and recorded again. We found that as predicted the ethanol slowed the heart rate, caffeine increased the heart rate and the water didn’t affect the heart rate as much. (As shown in the graph below).

This experiment gave us extra knowledge on the anatomy and physiology of the daphnia. It was very interesting to see how their body reacts with different substances such as ethanol and caffeine. We came across offspring developing inside the female daphnia which we found really fascinating. The fact that their bodies are opaque make them a great lab organism. During this experiment we had to repeat the steps 10 times for each substances which became really repetitive and frustrating. Another difficulty we faced was when we were counting the heart rate, as it was too hard to watch and record through the microscope at the same time and this caused anomalies. Overall the experience taught us a lot and helped us gain more experience for the future. 

Y12 Students share their experiences in the innovation labs

During the next few weeks I will publish a series of blog posts written by our year 12 students reflecting on the first term of Project Based Learning at the UTC. It has been a really exciting first term with the students taking part in a range of interesting projects in the labs.

Saturday, 31 December 2016

Sleep inducing molecules: Propofol, for January 2017

One of the essential tools of a hospital doctor is access to reliable and safe  anaesthetics. Today, Propofol is one of the most commonly used general anaesthetics and forms subject of this post. Its chemical structure is shown on the left and, as I think you can see, it looks a little like the side chain of the proteogenic amino acid tyrosine (Tyr or Y), or, as the chemical name indicates, the commonly used disinfectant, phenol (which your grandparents would have called carbolic acid, or simply carbolic). Today, you will find phenol in small quantities in many products, largely owing to the low cost of production and its general disinfectant properties. It is an ingredient in many oral hygiene products, soaps, cosmetics and is a measurable component of Islay Scotch Whisky! Now we are getting closer to the anaesthetic properties of propofol! I should provide a definition and the etymology of the word anaesthesia, before I go any further. The word (sometimes without the second "a") was introduced by the famous American Poet, Medic and Social reformer Oliver Wendell Holmes in 1846, to describe the inhibition of sensation: and is derived from the Greek αν-, an-, "without"; and αἴσθησις, aisthēsis, "sensation").

Phenol, the "molecular core" of propofol, was first isolated in the early 19th century in coal tar and later in petroleum. The dissociation of the "12-o'clock" OH at high pH, makes phenol a weak acid: the benzene ring draws electrons asymmetrically from the oxygen, facilitating  release of a proton and supporting (I assume) inter-molecular hydrogen bonding. Hydrogen bonding, together with ring related van der Waal's interactions, gives phenol its relatively high melting point (around 40 degrees C). It is a white crystalline solid (RHS) at room temperature, but is hygroscopic (that volatile alcohol group again) and is often a bit of a mess in a bottle in the summer! Getting back to propofol, my question is really how can the basic skeleton of phenol in conjunction with a symmetrical pair of isopropyl groups (-CH3-CH2-CH3), make most humans fall fast asleep in a couple of minutes! 

The first general anaesthetics to be introduced into modern medicine (I shall not discuss natural products here), follow the path of the European Industrial Revolution and the birth of the Chemical Industry. Joseph Priestly suggested the application of nitrous oxide (laughing gas, N2O) at the turn of the 19th century and, following the ancient uses of extracts of poppy, opium and morphine became (and remain) potent analgaesics (without pain, as opposed to sensation), in intensive therapies and surgery. But the most widely used anaesthetics in the second half of the 19th century included ether (diethyl ether) and chloroform. As you will appreciate, the rate of diffusion of these gases is an important feature of their rapid action in creating sleepiness and hallucinogenic effects.

Propofol was first discovered nearly 50 years ago at ICI, Cheshire (I assume Macclesfield) and a patent filed under the number ICI 35868: clinical trials were first reported in 1977. Unlike phenol, propofol is tricky to formulate, since it is much less soluble in aqueous solution, and is prepared as more of an emulsion. [I wont discuss formulation any further here, but this is a critical aspect of the development of any drug, or personal care product, as you can imagine, but one that is less frequently discussed; look here if you are interested in formulation.] It has been shown that propofol binds to a range of proteins in vivo including serum albumin, but more recently, its interaction with the GABA receptor has been proposed as a key part of its effectiveness as an anaesthetic (shown right is the proposed interaction between a derivative of propofol with a transmembrane region of the GABA-A receptor), from work by a US-UK collaboration between the laboratories of Evers and Franks)

My final point about general anaesthetics, such as propofol, relates to their mechanism of action. Understanding the mode of action of these compounds is a real challenge for Molecular Biologists. Clearly, propofol and GABA (gamma amino butyric acid, shown left) are unlikely to be competitive inhibitors! It seems clear to me that this is an area of research that requires a "systems biology" approach combined with high resolution structural biology (the work on mapping the GABA-A site came from the use of tagged profolol analogues). The interference with nerve transmission via chemical events and electrical events (such as those orchestrated by our portfolio of ion channels), appears to underpin the anaesthetic properties of molecules like propofol, but rationalising, improving and making future anaesthetics safer is such a key area of pharmacology, that I hope this molecule of the month might stimulate further discussion with students who have a general interest in the Molecular Life Sciences. Oh and Happy New Year to all of my readers!