How does our immune system work ?

Posted on November 14, 2015 by | 1 comment

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

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Where did that tickle come from?

Posted on November 9, 2015 by | 1 comment
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

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The Unique Features of Coral

Posted on November 8, 2015 by | 2 comments

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

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.

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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

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How Many You’s Are There? – The Intrigue of the Multiverse

Posted on November 7, 2015 by | 3 comments

The answer seems obvious – one!

After all, we have a unique set of genes that separate us from everyone else in the universe.

But what if there are multiple universes?

A new study has taken the scientific community by storm this week. Ranga-Ram Chary, a researcher based out of the California Institute of Technology, claims to have evidence that our universe may have collided with an alternate one. He extensively mapped out the cosmic microwave background (CMB), which is the light emitted during the early Big Bang stage of the universe, and removed stars, gas, and dust, effectively leaving nothing but noise. However, Chary discovered patches of unexpectedly brilliant light. The implication of these light signatures is that they appeared when a universe with a different baryon-to-photon ratio bumped into our own universe, leaving their “fingerprints” behind.

CMB after 9 years of data | By NASA / WMAP Science Team [Public domain], via Wikimedia Commons

Let’s not get carried away just yet. After all, Chary concludes that there is a 30% chance that the emissions are not unusual, and his paper is yet to undergo peer review. But the idea that yet-to-be-observed universes could be out there has intrigued humans for years. Hugh Everett first formulated the many-worlds hypothesis in 1957, which states that there may be an infinite number of universes and that every event with multiple outcomes occurs in a different inaccessible branch of the multiverse. We have developed newer, more sophisticated theories since then, such as the model of eternal inflation – the idea that the universe has always been expanding and thus creating pocket universes, which are infinitely far apart.

Bubble universes | By English: Original by K1234567890y Vectorisation by Lokal_Profil 中文: 原作由K1234567890y制作 Lokal_Profil使用Vectorisation重制 [Public domain], via Wikimedia Commons

Generally speaking, the multiverse hypothesis and the notion that there exists a set of infinitely possible universes that are beyond the realm of what we can experience is a hotly debated topic. After all, how can we test a theory that allows for all possible outcomes?  Physicist Paul Davies argues, “For a start, how is the existence of the other universes to be tested? To be sure, all cosmologists accept that there are some regions of the universe that lie beyond the reach of our telescopes, but somewhere on the slippery slope between that and the idea that there are an infinite number of universes, credibility reaches a limit. As one slips down that slope, more and more must be accepted on faith, and less and less is open to scientific verification.”

The multiverse question is not only one explored by quantum mechanics but also by philosophy. Modal realism is an idea propagated by David Lewis which suggests that all possible worlds are just as real as the one we are actually experiencing, and saying our world is the actual one is simply our way of distinguishing it from others.

The multiverse hypothesis demands an inconceivably great burden of proof and we may never know if it is true in any of its infinite forms. Yet, nothing perplexes the human mind more than attempting to explore ideas that are virtually impossible to validate. One thing I do know: the multiverse is freaking awesome.

Minute Physics explains the science behind parallel universes: YouTube Preview Image

Tim Cheung

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Sniffing out Parkinson’s

Posted on November 5, 2015 by | 5 comments

Even if you have not been personally affected by Parkinson’s, this terrible disease affects all Canadians. Parkinson’s is the second most common neurodegenerative disease (after Alzheimer’s disease), affecting voluntary movement and leading to common symptoms of tremor, slowed movements, and muscle rigidity. Nearly 100,000 Canadians have Parkinson’s and no cure. The economic burden of Parkinson’s in Canada is huge. The total cost of Parkinson’s is estimated to be $558.1 million, equating to an average cost per capita in Canada for the disease to be $23/year.

The onset of Parkinson’s may not be apparent at first, leading to a lengthy diagnosis, relying on the process developed by Dr. James Parkinson in 1817. Diagnosis depends on a complete neurological examination to confirm two out of the three common symptoms and to rule out any similar disorders. No tests, blood or diagnostic, exist to definitively confirm the disease. However, one woman has recently astounded researchers by her ability to detect the disease with shocking accuracy – through her sense of smell.

Joy Milne with her late husband. Credit: CBC News

Joy Milne with her late husband.
Credit: CBC News

Joy Milne of Perth, Scotland, noticed her husband’s scent changed six years before he was diagnosed with Parkinson’s. She describes it as a distinct, musky smell, but didn’t make the connection between the smell and the disease until she joined a charity for Parkinson’s and encountered other Parkinson’s patients emitting the same distinct smell. Intrigued, researchers at Edinburgh University tested her claim by subjecting her to a blind “smell” test. Researchers gathered six healthy people and six who were diagnosed with Parkinson’s and asked them to wear a t-shirt for a day, and collected the t-shirts for Joy to smell. Joy’s accuracy was remarkable, scoring 11 out of 12. However, she was adamant that one of the healthy subjects had Parkinson’s. Eight months later, she was proved correct – the subject informed researchers that he had been diagnosed with Parkinson’s, meaning Joy’s accuracy was actually 100%.

Scientists are thrilled by this phenomenon, and are trying to use Joy’s ability to develop a definitive test for diagnosing Parkinson’s. They believe that the disease causes a change in the skin of Parkinson’s patients early on, causing the distinct odour detected by Joy. A simple test, such as swabbing a subject’s skin to detect the change, would allow for much faster diagnosis and much earlier treatment. While this discovery may have been accidental, it definitely has many implications and consequences in the way this disease is treated.

– Peggy Hung

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What triggers Allergies?

Posted on November 2, 2015 by | 1 comment

 

antibodies_and_antigens

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.

Smansoni4

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.

-RikulThapar

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Posted in Biological Sciences, Issues in Science, Science Communication

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How Harmful are Cancer-causing Meats?

Posted on November 2, 2015 by | 3 comments

You may think the title of this post is an oxymoron: if something is cancer-causing, it must be pretty harmful, there is no question! This is also what most people thought when they read the headline few days ago, about the fact that processed meat has been classified as a “definite” cause of cancer, and red meat a “probable” cause. But what many people didn’t realize is the difference between “evidence” and “risk”. Granted, the announcement on the consumption and effects of meat made by International Agency of Research on Cancer (IARC) is based on more than 800 studies and is definitely backed up by scientific evidence, but the overall risks of processed and red meat are still much lower in comparison to other cancer-causing things such as smoking, thus much less harmful than what we perceived them to be.

Grilled and Smoked Meat | Copyright @ 2010 by DeusXFlorida, Flickr

To clear up some definitions, “processed” meat is meat that has been modified to extend its shelf life or change the taste using methods such as smoking, curing, or adding salt or preservatives, according to a BBC article, while “red” meat includes beef, lamb, and pork. There is now evidence that bowel (or colorectal, colon) cancer is more common among people who eat the most processed and red meats, with the most convincing evidence being a study by researchers at the World Cancer Research Fund (WCRF). The study showed that people who ate the most processed meat had a 17 % higher risk of developing bowel cancer compared to those who ate the least, which is equivalent to 10 more people developing bowel cancer among 1000 people.

The IARC classifies a particular cancer risk as one of five categories, representing how confident they are that it causes cancer. Processed meats have been given group 1 classification, which “definitely” causes cancer, while red meat is in group 2A and “probably” causes cancer. However, even though processed meats is now in the same category as alcoholic beverages and tobacco, it does not mean they are equally dangerous. To put things into perspective, Cancer Research UK estimated that about 19% of all cancers were caused by tobacco, and only 3% are caused by eating processed and red meat.

This video summarizes the news, the limitations, and some perspectives on this topic: YouTube Preview Image

-credit: PBS NewsHour

Now that it seems like there is no need to suddenly turn vegetarian if you didn’t intend on becoming one, it could also be wise to cut down on processed and red meat. Perhaps eating smaller and fewer portions of red meat, choosing chicken and fish over beef and lamb, or adding more vegetables and pulses is some thing to consider doing. After all, red meat does have its nutritional benefits too: high content of iron, vitamin B12, zinc, protein, all are important for our body. And with more and more food becoming carcinogenic, a moderate diet of any kind is always more beneficial.

-Even Zheng

I commented on Bowen Zhao’s post on “Benefits of Eating Insects”, Doris Stratoberdha’s post on “Who’s this stranger starring at me?”, and Sogand Goharpey’s post on “Smarter by playing a music”.

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