Blog Archives
Why Thanksgiving Makes You Sleepy
In the spirit of Thanksgiving, today’s post will deal with tryptophan and if it makes you sleepy. We all know thanksgiving as a holiday of food. A veritable cornucopia of various dishes. What most people complain about is the feeling of sleepiness after eating lots of turkey. Most of us like to blame the copious amounts of food we consume on causing what we colloquially call “food coma.” However there is known evidence over the last 20 years that shows that in fact its turkey’s higher levels of L tryptophan (an essential amino acid) that creates that sleepy feeling. Tryptophan is converted into Serotonin via a biochemical pathway. Since serotonin is a neurotransmitter often responsible for sleep/ tiredness one can infer that more turkey = more tryptophan = more serotonin= more sleepy. Read the rest of this entry
Motor Unit Recruitment Strategies During Deep Muscle Pain
When you hurt your arm, leg, or back, the first thing you’d often notice is that ones’ range of motion tends to decrease. It hurts to move, or your muscles feel achy. Despite this pain previous medical research has no solid explanation for the fact that despite pain and obvious torn/ damaged muscles, individuals are still able to perform tasks with the same amounts of force as an individual who is not in pain. Researchers recently have hypothesized that individuals who are experiencing deep tissue pain, in fact recruit more muscles to help out the torn/ damaged muscle do its task. This might seem painfully obvious but it is not. Up until this point the current theory/ model of muscle recruitment during pain stated that muscle groups take from other limbs or major muscles to help get a task completed. Lets dive a bit further into this issue and I”ll attempt to lay it out nice and simple. Read the rest of this entry
Venomous Animals (Deadly Animals With Amazing Cures)
When most people think of venomous animals, their first reaction is to think of snakes. This is an accurate thought process as snakes are indeed venomous animals, infamous for killing individuals in a terrible way. However, snakes are not the only creatures that have evolved a chemical defense like venom. There are venomous birds, frogs, fish, even mollusks! The duck billed platypus contains a venomous barb on its hind paws that it can use for defense. Today’s post will deal with one of these venomous animals that should be coming into fame soon. The Geographic Cone Snail. Read the rest of this entry
Thin Layer Chromatography and its uses in Pharmacognosy
The word pharmacognosy is derived from the greek words “pharmakon” which means drug and “gnosis” or knowledge. This is the study of drugs from natural products. These natural products are typically derived from plant sources, like aspirin, or methanphedamines or caffeine. However some compounds come from animal sources, such as the novel drug Conotropin, which is derived from conotoxin ( a potent neurotoxin found in geographic cone snails). Think of the pharmacognosist as the modern day alchemist.
TLC of a plant extract
As their assays typically require identifying the base constituents of a larger compound, these scientists rely on an array of separation techniques to help them sort out compounds into their base components. One such technique is thin layer chromatography. Thin layer chromatography or TLC as its more commonly known, is based on the general concept that objects will move through a medium of evenly spaced particles based on their molecular weight. Think of this analogy. You have two small children running from two fat men. If the children run to a play ground and move through the playground equipment they will get out of the climbing structure much faster than the two fat men will. These children have passed through quickly because of their smaller size. This is true also of molecules in an aqueous solution. The larger particles will move slower through a matrix than smaller particles will. In this case it become possible with a consistent media usually of powered glass (silica) to separate things by molecular weight. This is the basic idea for chromatography. Now thin layer chromatography relies on several key factors. First it relies on the fact that a solute system has been designed that due to its polarity helps to separate out the compounds of interest ( think of this as a liquid to help move the particles through the matrix). In high school chem lab, many of us performed the simple experiment where we took a sharpie or black inked pen and drew a dot on it. We then placed one end in water and let the water wick upward. This separated the ink out by color. The reason this worked is because the water is an extremely polar compound. It thus pulls the ink apart into its basic components which happen to be multiple colors of ink. These components then travel along the plate until the solvent front stops at the top. This can be seen in the example below. The ink has separated out based on its components molecular weights. To help more with this explanation, the yellow ink is the lightest in weight and thus has traveled farthest on the plate.
Black ink on a TLC Plate
So how is this useful you might ask? Does this assay tell us anything about the constituents themselves? Can I identify what they are? Do I know the molecular make up of that yellow banding? The answer is of course no. However, TLC can be used as a basic step to help us later answer these questions. Variations to our TLC assay can help us to actually identify what the banding patterns are. Special sprays that interact with the separated compounds can produce a color change for example that help to identify the compounds within. For example, potassium dichromate spray can help to identify the presence of any organic compounds within the original sample. Also by varying the solvent system, (mixing in water with an alcohol or organic solvent) we can change not only the rate at which the solvent travels but also the clarity and resolution of separation. We can also use a fluorescent plate that will cause particular samples within the matrix to change color under a UV light.
Identified bandings
Steps for a TCL assay
