Category Archives: Biological Sciences

Terminating Species for the Greater Good

Have you ever wished for an annoying species to disappear off the face of the Earth? Do some species seem to exist just to cause misery for the rest of the animals on this planet?

If you answered “yes” to any of the questions above then you are in luck! Humans have invented a clever way to get rid of pest populations. It is called the Sterile Insect Technique (SIT). This technique has existed since the 1950s and was pioneered by Dr. R.C. Bushland and Dr. E.F. Knipling. As you can tell from the diagram below, the concept of this technique is very simple. Basically, nuclear radiation is used to make the male species of the pest you are targeting infertile. Then these males are released into the wild. The wild females cannot detect that the males are infertile so they will still mate with each other. After mating, the females will lay their eggs but the eggs will never hatch because of the mutations the radiation causes.


The Sterile Insect Technique (SIT) involves releasing sterile males into the wild. The sterile males can still mate but no eggs will be fertilized. Credit:

Here is a video that does an amazing job of introducing SIT.

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Credit: FAOVideo

You may be wondering if humans should be playing God but SIT is currently safer than using conventional means such as pesticides. With pesticides, it is not just the pests that suffer but everyone else. Helpful bugs such as butterflies and ladybugs can be harmed. Pesticides also ruin the environment by contaminating soil, water, air, and non-target plants. Even you can be harmed since pesticides easily stick to food products and are hard to get rid of. It is estimated that one million people worldwide per year die from pesticide-related causes.


SIT is safer compared to pesticide use. Credit: Wikimedia Commons

Another reason the Sterile Insect Technique is beneficial is that it can exterminate pests that can’t be targeted by pesticides. These pests torment livestock and humans. The first species that was experimented on using SIT was Cochliomyia hominivorax, a parasitic fly known as the screwworm fly. Unlike normal parasitic maggots which eat dead flesh, screwworm maggots only eat the living flesh of warm-blooded animals. If you’re wondering why the flies are called screwworms, that’s because if the maggots are disturbed, they will “screw” themselves deeper into the flesh. This causes severe injuries and death in livestock. Thankfully, the U.S. has managed to officially eradicate this nightmare in 1982 using SIT.


The adult form of the screwworm fly. Credit: Wikimedia Commons


The larva form of the screwworm fly. A wound can contain hundreds of larvae. Credit: USDA

Although this technique is very effective and safe, there are still limitations such as being expensive and requiring high levels of training and security. In the future, as technology improves, Sterile Insect Technique may become reliable enough to replace pesticides.

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A modern-day example of STI being used to eradicate mosquitoes. Credit: TheLipTV2


-Bowen Zhao

New Material Stores Oxygen for Later Use

Oxygen is an important element required for metabolisms occurring in our body and without it we would be dead in a couple of seconds. This is the reason that we cannot survive under the water or any other place without oxygen. Scientists  at University of Southern Denmark found a new way to store oxygen for using in places that oxygen is not available. They made a substance based on cobalt which can absorb oxygen from its surrounding air or water and release it anytime it is needed.

By Kenneth Abbate , via Wikimedia Commons

Oxygen can bind many different materials but the result is not always useful. For instance, oxygen can spoil foods or can rust metals. Professor Christine McKenzie, one of the researchers, explains that this new material can reversibly react with oxygen which means it can be used to transport oxygen and release it in its initial form similar to what hemoglobin does in our body. Cobalt is responsible for determining the structure of this new material in a way that it has affinity for oxygen same as iron in our body. Professor McKenzie added that the rate of oxygen absorption can range from seconds to days because of several factors such as atmospheric oxygen content, temperature and pressure. Furthermore, the material releases oxygen when it is heated up or placed in a vacuum. This material can be used to make many useful devices. For example, a light weight device could be designed to provide oxygen for patients with lung diseases who have to carry heavy oxygen tanks with themselves all the time. In addition, divers can use this material to stay longer under the water since it can absorb oxygen from water if the diver breathes in all the available oxygen in the material.

By Stephan Borchert (Eigenes Werk.) via Wikimedia Commons

-Amir Jafarvand

On immortality: a very human desire

If presented with the fountain of youth, would you drink?

People have entertained the idea of immortality across time. Greek mythology tells of the phoenix, a bird capable of rebirth. The prominence of comics as a publication medium early in the twentieth century gave rise to a slew of superheroes capable of super-regeneration and longevity, like Superman and Wolverine. Even Lord Voldemort [SPOILER: highlight to reveal] went through the trouble of creating seven horcruxes to secure a strong hold of the living realm. Why are we fascinated with the concept of immortality?

The motivation to discuss immortality is probably related to people’s natural aversion to death and aging. There are plenty of cosmetic products and procedures that generate a lot of revenue by reversing the effects of aging, such as Botox. But what if instead of merely combating the symptoms of aging, you could eliminate it completely?

Certain examples of non-aging exist in nature. Hydras have been observed to not age. While not quite immortal, lobsters have shown to not be strongly affected by age. What can we learn from these organisms?


In DNA replication, DNA polymerase takes up a short space on the sequence that it doesn’t copy, like painting itself into the corner of a room. Image from ClipartHeaven.

At the ends of our DNA strands are sections called telomeres – repeats of nucleotides that prevent degradation of the gene as it replicates over time. Every time a cell divides, the telomeres get shorter. After many replications at a point called the Hayflick limit, the telomeres reach a critically short length and the cell stops dividing. In a way, telomere length is like a biological clock that can be used to determine lifespan.

Cells also produce an enzyme called telomerase, which adds nucleotide bases to the ends of telomeres. However, the rate of telomerases’ repair of the telomeres is overcome by the rate of cell division, so telomeres continue to grow shorter and the cell ages.


6_telomere_2 6_telomere_3 6_telomere_4
Telomerase. Here, “senescence” means “old age”. Images from the National Institutes of Health.

So does the answer to immortality lie in telomerases? Not quite. High telomerase activity is detectable in more than 90% of malignant tumours. The action of telomerase can provide cells with the capacity to infinitely replicate – a defining factor of tumour cells.

So where does this bring us? We aren’t any closer to living forever, but average life expectancy has risen over time, owing to advancing medicine and lower infant mortality rates. Still, it is just as interesting to ponder how one might spend lottery winnings as it is amusing to think about what one would do with unlimited time. Perhaps the search shouldn’t be for biological immortality, but to leave an immortal legacy. As A. A. Milne had said, “I suppose that every one of us hopes secretly for immortality; to leave… a name behind him which will live forever in this world.”


“Life Expectancy at Birth by Region 1950-2050” by Rcragun from Wikipedia.

– Trevor Tsang

How does our immune system work ?

We are constantly encountering pathogens (anything that can cause disease), so why don’t we become sick more often?
The answer to this question is our immunes system, which is responsible for protecting us from diseases.

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                                     The immune system
                      Credit: In a nutshell – Kurzgesagt

From a scientific point of view, the immune system includes many biological structures and processes that an organism has in order to response to diseases that come from bacterial or viral infections.
The immune system reacts to diseases with layered defenses of increasing specificity. There are two lines of defenses in our body: 1- innate defenses, 2- adaptive defenses

Cells of Immune system      Credit: Wikimedia

The innate defenses include two major parts. In the first part, there are physical barriers such as a tough outer skin, mucous membranes and secretions that are all impenetrable to viruses and bacteria. In the second part, which is more detailed, body protects itself by phagocyctic cells and natural killer cells, which are white blood cells. In addition to these white blood cells, complement proteins and the inflammatory response (swelling, fever and redness) also play important roles in this kind of defense.
After innate defenses, there is a more specific line of defense, which is called adaptive immune response. This kind of defense provides immunity against particular pathogens that the innate immune response is not able to kill and remove them. T cells and B cells are lymphocytes that play the most important role in the adaptive immune response.
B cells respond to presence of pathogens by recognizing them, secreting antibodies which are types of proteins that bind to pathogens and inactivate them and create the memory of them.
The last part of the adaptive immune response is T cells. These cells have receptors on their surface and use them in order to recognize infected cells, kill invaders and stimulate more B cells.

Adaptive immune response        Credit: Wikimedia

Kamyar Kazemiashtiani

Where did that tickle come from?

Newborn baby. Credit: Wikipedia

Newborn baby. Credit: Wikipedia

Babies are a tiny package of wonderful, but their minds are very mysterious. What do they think, and how do they perceive the outside world? Even if they had the chance to explain this, how could they with a brain that completely lacks vocabulary? Are babies’ perceptions like ours?

So many questions asked about these mysterious minds, and a recent paper published October 19 2015, offers some insight. Andrew Bremner of Goldsmiths, University of London and his colleagues observed tickling responses in infants and adults, the study was published in the Current Biology journal.

The research focused on 4-month-old babies, 6-month-old babies and adults and their reactions to remote controlled tickling sensations. During the study, the legs or arms are crossed and their foot or hand is tickled. How the individual responded was quite interesting. So, the left hand (now crossed over to the right side) gets tickled, they would see the right side of the body get tickled, but feel it on their left hand. The mismatch between sight and touch can interfere when correctly saying which hand was touched. The same method was used for the feet.

Newborn baby . Credit: Wikimedia Commons

Newborn baby. Credit: Wikimedia Commons

Unfortunately, I could not find any video footage but the paper includes detailed figures and diagrams.

The researchers wondered if the same responses would come from infants with little visual experience. It turns out that 6-month old babies and adults were both fooled by the cross-over, but 4-month-old babies didn’t fall for the trick. With only a 2-month gap, the younger babies were more in tuned with their self and oblivious to the outside world.

Bremner suggests that young babies don’t link their physical body to the outside world, this is learned during the 2 month period.  Young babies live in a very different world; one where visual objects are not necessarily connected to the physical being.

As babies grow and learn, they start making these connections and become more alike. They gain knowledge and lose the mysteriousness they were born with. Wouldn’t it be amazing to fully understand what that tiny island is like living on? Maybe one day.

Danielle Marcotte

The Unique Features of Coral

Corals are eukaryotic animals that have existed for more than 500 million years. They are found in abundance in shallow tropical waters, where sedimentation rates are low, nutrients are scarce, and water temperatures are warm. They also have a wide variation in morphology which allows them to better adapt to the different environments in the ocean. The base of a coral is called the corallite. The corallite is made of calcium carbonate and contains the polyp. The polyp is the softer portion of the coral that surrounds its mouth. The polyp further extends to tentacles that contain cnidocytes. Cnidocytes enclose structures called nematocysts that help the coral capture its prey. Each nematocyst is attached to a thread on one end, and the other end of the thread can be barbed. When a prey is detected, the thread is ejected from the nematocyst to either trap or inject toxin into the prey. The prey will then be devoured in the stomach of the coral and any waste will be expelled back out from the mouth.


Coral Polyp. Credit: Wikipedia

Corals come in a variety of shapes due to the differences in wave strength and sunlight of their location in the shallow ocean waters. For example, corals that live deeper on the reef tend to be flat to better capture sunlight and food, whereas corals that live closer to the shore branch out so the strong ocean waves don’t break them. Perhaps all these factors combined is what helped corals exist for such a long time.

Coral outcrop on Flynn Reef

Coral outcrop on Flynn Reef. Credit: Wikipedia

Above all, corals display an interesting symbiotic relationship with a dinoflagellate called zooxanthellae. These zooxanthellae are photosynthetic algae that live in the polyps of corals. One advantage of their relationship is that through photosynthesis, zooxanthellae supply high amounts of oxygen for coral. A second advantage is that zooxanthellae provide as much as 95% of the coral’s energy source.In addition, zooxanthellae help increase calcium concentrations for the corals to use for corallite formation. It was found that corals with zooxanthellae can grow three times faster than corals who don’t have zooxanthellae. In a research done by Pearse and Muscatine, they also found that “corals with symbiotic algae calcify many times faster in light than in darkness, while corals which have lost their zooxanthellae calcify at rates which are slower and unaffected by light”. Pearse and Muscatine also looked at the relationship between the uptake of phosphate by zooxanthellae and growth of corals. It is hypothesized that the uptake of phosphate by the algae can assist calcification in corals. However, the results found under their conditions were not significant, otherwise there would be a fourth advantage to the symbiotic relationship between coral and zooxanthellae. As for zooxanthellae, the coral provides them a place to live, a supply of carbon dioxide to use in photosynthesis, and protection.


Coral and Zooxanthellae. Credit: Ocean Portal

I believe that these are the unique features of corals that helped them exist since the late Cambrian period. Their symbiotic relationship with zooxanthellae is even more fascinating. Corals and their algae friends are still being researched to find more advantages in their symbiotic relationship. Without these algae, corals certainly have a decreased chance of survival.

Here is a short video on Coral:

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Stephanie Lam

What triggers Allergies?



Some of the things that we’re allergic to – such as peanuts and pollen, for example – carry compounds that resemble proteins found in parasites. It is found that allergic reactions are actually miscommunicated immune responses: For our own protection, our bodies produce antibodies, which attack similar but harmless compounds. The action of an antibody on a harmful compound can be described through the following video:

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Various environmental and food proteins called allergens are recognized by an immune system antibody called immunoglobulin E (IgE). This part of the mammalian immune system is thought to have evolved as an additional rapid response mechanism to combat parasitic arthropods and worms called helminths. If IgE-mediated immune responses evolved to provide extra protection and not to cause allergic reactions,  then environmental allergens such as pollen should share key molecular properties with the parasite antigens that are specifically targeted by IgE in infected humans.antibodz

To test this, a team led by Nidhi Tyagi from the EMBL-European Bioinformatics Institute identified epitopic-like regions in 206 parasitic proteins and as the first example, it was found that a plant protein (BetV1) has similar binding sites for anti bodies, as it is found for allergens such as pollen in a worm. This confirms that the immune system targets allergens (Both plant protein and harmful parasites) via IgE antibodies and causes immune responses which fail to differentiate between useful and harmful compounds.

Their research also helped them to list 2,445 parasite proteins that show significant similarity in both sequence and structure with allergenic proteins, which can cause immune response against useful proteins. The research team then measured antibody responses in blood collected from 222 people living in the fishing village of Namoni on the shores of Lake Victoria in Uganda. These community members were suffering from schistomsomiasis which is caused by the worm Schistosoma mansoni(pictured below). The blood was collected immediately before anti-schistosomiasis treatment and five weeks afterwards.


It turned out that a plant protein called BetV1 – the commonest allergen in pollen – is a target of IgE in humans infected with schistosomiasis.

Tyagi’s research adds to one of those definitions: environmental and food proteins that are similar to those parasite proteins against which IgE is an observed marker of protective immunity. Defining allergen-like molecules in parasites and understanding their link to the unregulated IgE response, will help with the discovery and design of molecules for future treatment of allergic conditions.