Why we woo

by Allan Johnson
Published: Sept 21
 

The problem

THE LONG, COLOURFUL tails on peacocks; the loud, distinctive cry of birds; the useless eye-stalks of some flies: All these traits are found in nature, even though all of them make the bearer an easier target for its enemies. But still, these traits are passed on through generations, making researchers wonder about their purpose.
Evolution is full of species that have naturally selected—and potentially dangerous—physical traits. Female peacocks, for example, prefer males with large and colourful tails, even though they make them easier for predators to spot.
A question arises: Why and how do animals choose their mates (something scientists refer to as sexual selection), and how does this selection affect the species? Does it hasten the removal of harmful genes, or does it promote diversity and speed up the development of the species?

The researcher

University of Ottawa biology professor Howard Rundle looks for logic behind sexual selection. Evolution happens at a different rate for different species, based on how long each generation lives and breeds. By using fruit flies for testing, with their short life cycle, he tracks evolutionary changes in populations in years instead of millennia, allowing him to watch evolution as it happens.

The project

Rundle set up many populations of flies and controlled for how they mate. For each population, he allowed some groups of flies to pick their mates themselves, while others were forced to select mates at random rather than according to their normal preferences.
After data from several generations was analyzed, it became clear how genes harmful to the flies were passed on. The answer surprised the researchers.
In theory, if sexual selection allows for harmful genes to be bred out faster than random mating, you’d expect less of those harmful genes in the flies allowed to mate selectively. Instead, Rundle found there were no differences between populations, and for a few genes, there were less copies of the harmful genes in the randomly mated population—completely the opposite of what you’d expect.

The key

With further analysis, the reason for the contradiction became apparent. While female and male flies both chose mates without the harmful genes, there were unforeseen consequences.
When males breed with healthy females, they inject the latter with proteins that put their reproductive systems into overdrive. This brings down their fitness compared to the females carrying the defective genes, hurting the healthy females in the long run.
This problem in studies of sexual selection has long been abundant with theories and absent in data. Experimental biology is finally catching up to

Chemistry as art

by Tyler Shendruk
Published: Sept 9

The problem

UNLIKE MEDIEVAL ALCHEMISTS, who only dreamt of turning lead to gold, modern chemists are experts at reshaping matter. They can produce many molecules, but the process is often wasteful and time consuming. On the other hand, Mother Nature is much more efficient at the task, proving that chemists still have a lot to learn.
Biological processes use enzymes to create specific chemical reactions with little waste and extreme precision. When compounds react to form new chemicals, they must overcome an interaction barrier keeping them separate substances. Enzymes are the tools that these systems use to lower interaction barriers so that a reaction can occur, and new compounds can be created. Enzymes accomplish this by temporarily tethering the reactants together and orienting them so that they approach each other in the best possible way, rather than just randomly reacting.

The researcher

Melissa Macdonald is a PhD candidate in André M. Beauchemin’s lab at the U of O, who knows that if chemists can learn to control and create their own enzymes, many reactions could be recreated more efficiently. In Macdonald’s eyes, chemistry can be an elegant art and not just a series of random reactions.

The project

One reaction in particular stands out for Macdonald: Worthless alkynes can become valuable amines by adding a nitrogen-hydrogen bond. Since amines are a common active ingredient in pharmaceuticals, it is shocking that this seemingly simple transformation is so difficult to reproduce. The usual process involves heating the reactants to extremely high temperatures and using metallic catalysts to lower the interaction barrier. It’s exactly the sort of problem that requires a more elegant, artistic strategy.

The key

By designing an organic catalyst that uses the same tethering method as enzymes, Macdonald tackled this notoriously difficult transformation. The tethering molecule directed the approach of the reactants so intelligently that the interaction barrier was reduced and the reaction could occur at room temperature without the help of toxic metal catalysts.

Membrane madness

by Tyler Shendruk

Published: Apr 7

The problem
ONE IMPORTANT STEP in water treatment is filtration. Nobody wants little gritty pieces of dreg or oily bits of gunk in their drinking water. River water is passed through membranes in water treatment plants which block oversized contaminants from going any farther. Making membranes with large surface areas, but with small enough pores (micro- or nanofiltration), is possible by casting polymers into a film. These films are either hydrophilic (water-loving) or hydrophobic (water-hating).
It turns out that most contaminants are oily, hydrophobic gook, and since “the enemy of my enemy is my friend” the contaminants are very likely to bury themselves in the hydrophobic membrane to hide from the water. They can’t get through at first, but eventually contamination degradates the membrane’s performance.
On the other hand, hydrophilic membranes have their own set of problems. The contaminants don’t like the membrane, don’t bury themselves in it, and so degradation is slower. But hydrophilic membranes tend to be significantly weaker than hydrophobic ones, and so will often break during water treatment.

The researcher
Takeshi Matsuura is a chemical engineer at the University of Ottawa who develops modified membranes that can improve the distillation and filtration processes. In particular, he is interested in modifying surfaces using large macromolecules that can be attached to membranes.

The project
Filtration science would really benefit from filters that are strong, and that do not rapidly degrade. Hydrophobic and hydrophilic membranes each have their drawbacks, but by combining them, Matsuura hopes that he can get the best of both worlds.

The key
While other scientists cast a strong hydrophobic membrane, and later modify it by grafting hydrophilic polymers on top to make a protective coating, Matsuura thinks this is too slow (and costly). He mixes the hydrophilic and hydrophobic polymers together in solution and then casts them. As the water evaporates, the polymers naturally separate. Matsuura is left with a single membrane with a strong bottom layer and protective coating on top. In just one step, he gets a surface modified film that has the strength of a hydrophobic filter, but degrades slowly like a hydrophilic filter. That really is the best of both worlds.

Busy bees

by Allan Johnson

Published: Mar 31

The problem
THERE’S AN OLD urban myth that scientists don’t know how bees fly, that their wings can’t beat fast enough to keep the bees in the air. In reality, bees beat their wings 200–300 times a second, courtesy of the most efficient metabolic rate in nature. This ultra-efficient energy use makes them the ideal creature for studying the workhorse of biological systems: the metabolism.
This system breaks down large energy storing molecules via a series of chemical reactions, each assisted by enzymes. This creates ATP, the energy-carrying molecule that provides power to all the other functions in the body. The general pathways of this process are common to all higher organisms, so what’s true for bees is true for the animal kingdom.

The researcher
University of Ottawa professor Charles Darveau studies metabolism from a physiological and evolutionary perspective, using bees as a model organism. By comparing metabolic differences across different species of bees and weighing them with physiological differences, he can identify which changes in the series of reactions that make up bees’ metabolisms are important.

The project
Most people are familiar with the honeybee and bumblebee, but there are over 300 species of bees in Ontario alone. Darveau has a wide array of species to make comparisons. In addition to this cross-species approach, he can also look at variations within a species to examine these changes. The goal is to develop a complete characterization of the metabolic process: which enzymes make key changes, what steps bottleneck the metabolic rate, and what kind of system is most favoured evolutionarily.

The key
Darveau’s research is on the fundamentals of physiological change, but it has a number of immediate consequences. Because bees burn energy so quickly and efficiently, their wing muscles can heat up to 40°C. This allows them to flourish in environments where many other pollinators would be unable to survive, making bees an important part of northern ecosystems. Darveau’s fundamental characterization also allows other researchers to determine which species have metabolisms suited to adapting to different conditions, vital in determining the impact of climate change on fauna.

Experimenting with evolution

by Tyler Shendruk

Published: Mar 16

The problem
LOOK AROUND YOU. The world is brimming with the diversity of life. The great assortment of species is so much a part of our world that we take it for granted. It’s easy to say that diversity results from the theory of evolution and be done with it. But why is there such a wide gamut of life and how does diversification actually unfold? The question isn’t ‘Does evolution happen?’ but rather ‘How does evolution happen?’
When we look back in time we see that evolution has been punctuated by bursts of spectacularly rapid diversification during which many new species suddenly appeared. This process (called adaptive radiation) is very fast compared to the usually steady march of evolution, but it’s still too slow for scientific study.

The researcher
Rees Kassen is the University of Ottawa’s Research Chair in Experimental Evolution. When it comes down to it, Kassen wants to know the answer to a straightforward question: Why are there so many different kinds of living things in the world?

The project
To study the process of biodiversity, Kassen needs to watch evolution take place in his laboratory. He can do this by studying microbes. Since microbes live for only a short time, Kassen can observe changes that occur over generations in only a matter of days. This makes microbes an ideal model for studying adaptive evolution.

The key
When Kassen places colonies of microbes in a beaker of nutrient-rich broth, the colonies choose to live at the centre where there’s the most food. Early on the colony is smooth and round. After a while, resources become scarcer and competition becomes more fierce. Some of the colonies realize that if they stop fighting for control of the centre and move to the fringes they will have an ecological niche all to themselves. And so some colonies fall to the bottom of the beaker where they evolve into brush-shaped colonies. Others rise to the top where they change into very wrinkly colonies.
The new ecosystem offers the microbes opportunities to specialize and to a certain extent determines the form of the diversity. On the other hand, it is competition for resources that drives the specialization. Kassen suspects that these two factors cause adaptive radiation to occur quickly and helps explain why diversification happens in bursts.

Blowing shit up, science style

by Tyler Shendruk

Published: Mar 9

The problem
RECENT IMPROVEMENTS IN technology have allowed scientists to accelerate electrons in ways that create high-energy, extremely bright, and short laser pulses. Before the invention of these lasers, scientists could not study how high-intensity ultraviolet and X-ray light interacts with matter. Now that such lasers exist, everybody’s dying to know what happens when you blast stuff with short, high-intensity, high-energy laser beams.
The obvious answer is that you blow shit up, and that’s cool and all, but the potential applications of these beams are much greater than that. High-intensity ultraviolet and X-ray lasers might be able to image materials that are currently challenging to study. But before scientists can use these lasers, they have to understand this completely unexplored area of light-matter interaction.

The researcher
Lora Ramunno studies computational photonics at the University of Ottawa. Using her parallel supercomputer (equivalent to about 600 desktops), Ramunno studies nonlinear optical imaging and the interaction between matter and intense laser beams.

The project
Ramunno decided to look at how tiny clusters of matter interact with a high-intensity laser pulse by simulating each and every one of the atoms. When atoms are hit by a photon of light there is some probability that they will absorb the photon and eject one of their electrons. This leaves the atom as a positively charged ion. At every step of her simulation, Ramunno’s computer program must stop and evaluate the quantum probabilities that give these rates before it can move on to the next step.

The key
Before the laser blows up the cluster of atoms, electrons escape from their atomic orbitals and the cluster becomes a plasma. The first few electrons that are ejected simply fly away and leave behind a charged cluster of ions. However, the electrons emitted later find themselves in this charged environment that they can’t escape from.
These electrons are free to zip around, but can’t leave the cluster, and from time to time they collide with unionized atoms. They usually don’t have enough energy to free an orbiting electron from the atom they collided with, but they can excite one of the atom’s electrons up to higher energy. Ramunno found that if a second free electron collides with the same atom that had been energized by an earlier collision, it has a better chance of releasing the orbiting electron. When pairs of free electrons work together like this the cluster charges more quickly than if the laser didn’t have any help and so the cluster explodes in a shorter period of time. Ramunno calls this process Augmented Collision Ionization.

Beating bromine

by Tyler Shendruk

Published: Mar 2

The problem
THE QUANTUM WORLD works quite contrary to our own concrete and everyday existence. When we are first taught about atoms, we are shown a solar system-like model with electrons orbiting the nucleus like planets orbit the sun. But physicists have known for nearly a hundred years that this picture is too simple.
Electrons are both a particle and a wave at the same time. So electrons shouldn’t just be thought of like planets, but also like a vibrating guitar string. These so-called wavefunctions can be experimentally probed and scientists understand them very well. But for more complicated molecules—combinations of more than just one atom—it becomes very difficult to directly see that theory and reality are the same.

The researcher
On top of being a professor in the physics department at the University of Ottawa, Paul Corkum heads the Attosecond Science Laboratory at the National Research Council. He is renowned for using a laser pulse to accelerate an electron out of its atom, turn the electron around, and drive it back into its orbital. When the electron recollides with the atom, short bursts of light are given off that tells Corkum about the environment in which the electron settles.
Using very short laser pulses, Corkum was able to take a high definition snap shot of the quantum cloud that defines where the electrons are around the atom.

The project
Taking high-resolution pictures of quantum orbitals is one thing, but filming a movie of the wavefunctions during a chemical reaction is another altogether. And yet, this is exactly the challenge Corkum set for his lab. Using the same technology he invented for imaging orbitals, Corkum wanted to watch a single molecule of bromine disassociate into two separate bromine atoms.

The key
Corkum blasted bromine gas with blue light. Blue is exactly the right colour to excite bromine molecules. Immediately after the blue light excites the bromine, the short laser pulse that knocks an electron out and drives it back in is shot at the gas.
Corkum saw that the blue light had not excited all the bromine molecules. This turned out to be an advantage since the resulting bursts of light from the recollision of the excited and the non-excited molecules mixed into beats.
The non-excited bromine acted exactly like a tuning fork: Corkum could use the beating between the bursts of light from molecules of bromine and from excited, separate atoms to see the difference between the two.