Researchers watch amyloid plaques form

Researchers at the University of Toronto Scarborough (UTSC) and Osaka University applied a new approach to take a close look at amyloid plaque formation, a process that plays important roles in Alzheimer's disease. The technique would greatly aid the development and screening for novel therapeutics that can manipulate the formation of the toxic amyloid aggregates.

Anthony Veloso, Prof. Kagan Kerman's PhD student in Chemistry, used a laser to trap amyloid-beta peptides and examined them under a fluorescence microscope as they aggregate, giving them an exceptionally detailed view of the process. The work appears on the cover of the current issue of Analyst, a journal of the Royal Society of Chemistry.

"This technique could accelerate the drug discovery process. It gives us a new way to examine the early phase of plaque formation, when the most toxic species of oligomers are formed," says Prof. Kerman, a faculty with the Department of Physical and Environmental Sciences at UTSC and the corresponding author on the paper.

Amyloid plaques are protein deposits that form around neurons and interfere with their function. The major constituent of these deposits are amyloid-beta, a peptide that clumps together to form harmful plaques in Alzheimer's patients, but is otherwise harmless in normal individuals.

To get a look at the early stages of the process, the Canadian researchers and their Japanese collaborators used a technique called optical trapping. A laser is focused into a very thin beam and aimed at solution containing amyloid-beta particles. The beam creates a small magnetic field, which attracts and holds the particles in place. Amyloid aggregates stained by a dye then glows under the laser light, and the image can be captured by fluorescence microscope.

By using this technique, A. Veloso and Prof. Kerman hope to explore how the aggregates are formed, and to eventually discover the role of amyloid aggregates in Alzheimer's disease. Utilizing the versatility of this technique, Prof. Kerman's research team can extend their studies to understand aggregate formation in other neurodegenerative diseases.

The technique will also become a novel strategy to test therapeutic compounds that could halt the formation of plaques. Prof. Kerman and A. Veloso are working towards the automation of the technique, allowing for many compounds to be tested efficiently.

Provided by University of Toronto Scarborough

Yeast Alive! Watch Yeast Live and Breathe

 

Introduction
Have you ever looked closely at a piece of sandwich bread—really closely? Notice all of those tiny holes? They probably got there thanks to tiny living organisms called yeast. Even though these organisms are too small to see with the naked eye (each granule is a clump of single-celled yeasts), they are indeed alive just like plants, animals, insects and humans. In fact, we have some interesting things in common with these little creatures!

When you breathe out, part of what you are exhaling is a gas known as carbon dioxide. Yeast also releases carbon dioxide when it is active (although it's way too small and simple an organism to have lungs). Yeast are so small you can't see individual ones very well. So how can you tell if they are alive or not? You can enlist a whole bunch of them to blow up a balloon for you!

Background
When you buy a packet of baker's yeast at the store, the organisms inside are in a state of inactivity so they don't need to eat (keeping them cool and dry helps keep them preserved this way). But when you mix them into dough, they wake up and begin eating—and making carbon dioxide.

When you make yeast-based bread, you often have to wait for it to rise. During this step the dough might appear to be growing. But what is really happening is that you're giving the tiny yeast organisms time to eat and create small pockets of carbon dioxide inside the dough, which is what makes the dough seem to grow larger—and which leads to fluffy bread! (Bread products that don't have yeast rise during baking thanks to other ingredients, such as baking powder.)

Why do the yeast organisms "wake up" when you put them into a dough mixture? Like other living organisms, they need food and water. So by putting them in a moist environment with nutrients (such as sugar), they become "active."

Materials
•    Fresh packet of baker's yeast (check the expiration date)
•    Tablespoon of sugar
•    Clear plastic bottle with a small opening (such as a water bottle)
•    Funnel
•    Small balloon
•    Warm water

Preparation •    Carefully stretch out the balloon by blowing it up a few times (might as well give the tiny yeast a hand!).
•    Pour an inch or two of warm water into the clear plastic bottle.

Procedure
•    Pour the packet of yeast into the bottle and swirl it around.
•    Now add the sugar, and swirl the mixture around a little bit more.
•    Stretch the balloon opening over the top of the plastic bottle.
•    Look through the bottle—do you see any signs of life?
•    Leave the balloon-covered, yeast-filled bottle in a warm place for 15 or 20 minutes.
•    Any signs of life? Do you see any changes in the balloon?
•    Will the yeast keep making more and more carbon dioxide? Why might it stop?
•    Extra: If you have more yeast, try making a loaf of bread from scratch. You can find simple recipes—with the science behind them—on the Exploratorium's "Science of Cooking" website.

[To get the full effect for the time-lapse section in our video we used three tablespoons of yeast, three tablespoons of sugar, and we allowed the mixture to sit for 40 minutes.]

Read on for observations, results and more resources.