Tag Archives: Genetics

Slow and Steady: New Research Claims That Removing The Appendix Decreases Risk of Parkinson’s Disease

Posted on November 5, 2018 by | 3 comments

Many people have a friend or family member who is afflicted by Parkinson’s Disease, a long-term degenerative disease affecting the brain’s central nervous system. Seemingly unrelated, many people also have removed their appendix, a small finger-like length of intestine that is widely removed due to appendicitis. Perhaps somewhat unexpectedly, a recent study analyzing more than 1 million people in Sweden has concluded that an appendix removal done decades ago may reduce the chances of developing Parkinson’s Disease (PD).

Scientists speculate that the removal of the appendix affects the development of an abnormally formed protein, named α-synuclein (alpha-synuclein), which is present in PD patients.

What Is Parkinson’s Disease?

Parkinson’s Disease is a genetic neurological (brain) disorder that can have significant impact on the physical and mental state of patients, with more than 55,000 Canadians diagnosed with PD. The onset of PD is slow, often alongside symptoms such as hand tremors and body stiffness.

Parkinson’s encompasses a wide subset of symptoms and related complications: restricting the movement of a patient gradually, eventually initiating other symptoms such as difficulty speaking, loss of coordination, and development of depression.

Prevalence of Parkinson’s disease in household population, by age group and sex, population aged 45 or older, Canada excluding territories, 2010/2011 Source: StatCan

Presence of α-synuclein In PD Patients

A protein called α-synuclein, in its misfolded (mutated) form, is fairly abundant in the appendix of both healthy people and PD patients. The mutated version of α-synuclein has the same structure as the version of α-synuclein that is found in the brains of patients afflicted by PD, which scientists have suggested causes PD by damaging the brain cells which control bodily movement.

Highly magnified image of mutated α-synuclein.
Source: Van Andel Research Institute

α-synuclein tends to travel from the appendix, leading scientists to investigate whether the protein present in the appendix is the same as the protein in the brain of PD patients.

Study on More than 1 Million Swedes Found…

Knowing this information about α-synuclein, Viviane Labrie (the first author of the study) and her team at the Van Andel Research Institute in Michigan analyzed 1.6 million Swedish medical records to find that appendix removal showed almost a 20% decrease in chances of developing PD.

The data analysis also showed that an appendix removal also delays the diagnosis of PD for the people in the data set who did go on to develop PD for more than 3 years.

Why Is This Important? 

Parkinson’s Disease is not only a devastating and debilitating disorder, but also it is increasingly common as the general population begins to age. In recent years, PD is affecting more than 60,000 people each year in the United States. As PD is the second most common neurodegenerative (brain disorder) disease in Canada, it is with hope that these findings will inspire investigations into the pursuit of a treatment for Parkinson’s Disease.

See below for a video posted by Parkinson Society of BC, showcasing a young patient and her goals despite her disorder.

An instalment of Parkinson Society of BC’s This Is Parkinson’s Disease campaign, sharing Hilary’s story: a real-life British Columbian living with PD.
Source: Parkinson Society of BC

-Allison Chiang

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One small fragment to bind a protein, one leap for celiacs!

Posted on October 8, 2018 by | 1 comment

In cities such as our own, gluten-free products are becoming increasingly available throughout grocery stores and restaurants. With exception of the health-conscious members of society, who is the primary consumer of these products? One such group is the portion of the population affected by the disorder known as celiac disease.

Rather eating gluten-free for health benefits, celiacs depend on these foods daily to avoid painful illness. In the United States, researchers estimated a prevalence of 1 in 141 peoples affected by celiac disease. Among the people affected many had been undiagnosed leading the researchers to conclude that celiac disease is not as rare as believed in previous years.

What is celiac disease?

What is celiac disease? Celiac disease is a disorder that inhibits those affected from consuming foods with gluten-containing ingredients such as wheat, barley, and rye. Celiac disease harms the small intestine making it incapable of absorbing nutrients during the digestion process which leads to illness. Celiac disease means an abnormal self-defence response is triggered within the body when gluten is consumed causing damage to the small intestine. If celiac disease is left undetected or untreated, common adverse health effects associated include anaemia (iron deficiency caused by iron loss) and osteoporosis (reduced density of bone material that increases chance of fracture). For example, anaemia as an adverse health effect from celiac disease can result because anaemia can be caused by a Vitamin B12 and iron deficiency. Because Vitamin B12 and iron are absorbed in the small intestine, this poses a problem for celiacs whose small intestines are damaged, leading to anaemia that will cause fatigue, weakness, and additional categorical anaemic symptoms.

Figure 1. Image outlining the causes of celiac disease. Source: Kim Moss Electronic Publishing Services Inc. 

Figure 2. Simplified diagram outlining the pathway of inflammation (swelling) for celiac disease caused by gluten antigens (foreign substance that induces a reaction). Source: Nature Genetics

https://youtu.be/nXzBApAx5lY

Video: Celiac disease – causes, symptoms, diagnosis, treatment and pathology. Osmosis YouTube channel.

Why is gluten triggering this disease and how is this discovery a leap forward for the celiac community?

Why is gluten causing these symptoms in people around North America? Gluten is composed of proteins called prolamins that are storage proteins (store key survival components for cells such as amino acids or metals). Prolamins are found in wheat, rye, barley, and corn which are common food ingredients. In a recent study conducted in Austria, a research team has discovered a method that provides the possibility of future treatments for celiac patients. The researchers utilized antibodies (proteins that neutralize invaders such as bacteria) to create fragments that bind and neutralize prolamins. Celiac disease currently requires a gluten-free diet that is expectedly followed religiously. The fragments created bind grains containing prolamin in everyday ingredients and has provided future studies the potential to revolutionize clinical treatments that improve quality of life. Discovered treatments can eventually be used to mask the prolamin, preventing it from being displayed to immune cells so an autoimmune response (self-immune response) is not triggered.

Before believing that you are affected by celiac disease, please be aware that irritable bowel syndrome (IBS) and intolerances to foods such as dairy are similar in symptoms. No need to panic yet, but always be sure to check with a physician if you are experiencing symptoms! With the prevalence of celiac disease in the United States being 1 in 141 people, a treatment to reduce gluten sensitivity or inhibit it completely would improve many lives. The production of the antibody fragment that targets prolamin is a leap for the celiac community.

– Vanessa Niedzielski

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Echolocation: How Two Seemingly Polar-Opposite Creatures Developed the Same Highly Specialized Skill

Posted on October 1, 2018 by | Leave a comment

Have you ever been walking through your house in the middle of the night with all the lights off, searching for a glass of water, but you feel an intense pain running through your body as you stub your toe on the counter? This would never happen if humans had echolocation: the ability to map out the area ahead of you by using reflections from high-pitched sonar signals.

Animal Echolocation
Credit: WikiMedia

Echolocation is an ability that is primarily used by dolphins and bats. This raises the question, why is it that dolphins: hairless mammals which live in the ocean, happen to have the same specialized ability as bats: which are furry, nocturnal, and flying critters?

Dolphins utilise a unique organ called the melon to send out high frequency clicks. They have a large depression in their skull to make space for this organ, allowing them to produce bisonar for orientation. Beyond this, echolocation gives dolphins an idea on the object’s shape and size, although it is not quite understood by scientists exactly how this happens.

Bisonar by cetaceans
Credit: Wikimedia

Bats dominantly use a method of echolocation called laryngeal echolocation, which is characterized by the production of very short wavelength sounds from their larynx. The connection between their stylohyal bone and tympanic bone enables the bat to neurally register and separate outgoing and incoming ultrasonic waves. They have evolved to differentiate between the pulses they produce and the echoes that they receive back.

Ventral view of the Florida Freetail bat, highlighting the tympanic and stylohal bones. Credit: Pacific Lutheran University Natural History 

This skill could potentially be relevant for humans today, as researchers are using this skill to test human echolocation in blind people. It has been revealed that some blind people were able to independently develop a type of echolocation, by utilising sound, they are able to map out the space they are in and develop an image of it for themselves. Some researchers are studying this ability, attempting to make it accessible for all who might need it.

So how is it that dolphins and bats have developed these extremely similar skills? Clearly, there is the fact that because dolphins hunt in murky ocean waters, and bats hunt late at night in the dark. Thus they both had to have evolved some method to cope with the darkness, but why was it that they developed the same method of echolocation independently? A team of scientists were trying to answer this question, and a paper in Science Advances announced that there exist genetic characteristics that could have helped dolphins and bats both develop this skill.

This international group of scientists searched through the genomes of each animal, searching side by side for any similarities in amino acid sequences. They found that bats and dolphins share amino acids linked to proteins involved in the development of a very specific set of fast-twitch muscles. These were the muscles that drive the “terminal buzz”, or the rapid high frequency calls that bats and dolphins both make when hunting.

Figure showing sudden increase in high frequency calls in a bat
Credit: The Gall Lab

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Sound clip of terminal buzz – the terminal buzz is the last pulses of an echolocation call sequence: and will speed up at the end because the bat is getting closer to the object it is interested in.
Credit: The Gall Lab

This similarity in amino acid sequence may be a part of what helped these two very different animals develop the same skill, but there is still plenty to uncover about the specifics of how dolphins and bats developed echolocation independently. However, we are much closer to uncovering this mystery than in the past.

Jin Kyu Lee

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Integrating Peptides into RNA-World

Integrating Peptides into RNA-World

The RNA-World

Over 4 billion years ago, the molecular precursors to life showed up in the inhospitable soup of chemicals that we can barely recognize as Earth. The identity of these first molecular precursors is a schismatic “the chicken or the egg” debate, splitting people between groups that support molecules that carry information and ones with enzymatic activity.

If only a family of molecules could both have enzymatic activity and contain genetic information. Thus we enter the “RNA-world”, RNAs are molecules with its unique properties of having enzymatic activities and contain genetic information, it is the perfect molecule to self-replicate and mutate to pave the way for peptide and DNA to take over each role more effectively. This was the widely accepted theory since the 1960’s and remain relatively unchallenged until recently.

File:Geological time spiral.png

The timeline of the biodiversity of Earth, it all started with a few molecules. Image Credit: United States Geological Survey

The Problems of RNA-World

An article in Biosystems and another in Molecular Biology and Evolution, showed why a peptide-RNA complex world view is better than RNA-world hypothesis at explaining what the primordial molecular precursors would look like.

The researchers, Charles Carter from the University of North Carolina and Peter Wills from University of Auckland, from the articles approached the subject from two angles. First, from the perspective of enzymatic activity, although RNA show enzymatic activity but RNA does not react well to change like proteins. As a result, in the environment 4 billion years ago when the sea was cooling rapidly, the only way enzymatic activity could have survived was through proteins.

The other problem was genetic information, because at the beginning there were no genes or genetic codes. The changes and mutations in RNA would only be reflected in its abilities as an enzyme. An RNA only world cannot explain how and why the changes in RNA would lead to the creation of a genetic code with the purpose to create proteins. Thus, leaving a gap between the RNA world to the protein and DNA world.

The Peptide-RNA World

They proposed that a peptide-RNA complex, with the peptides that contain enzyme activity and RNA for genetic information, would fill the gap that the RNA-world cannot explain. This relationship would directly explain how mutations in RNA would affect enzymatic activity in protein, and why it needs to create better proteins to protect itself from a wider variety of situations. Furthermore, the addition of proteins explain how the first molecular precursors could survive in the ever-changing climate of the relatively new Earth.

https://upload.wikimedia.org/wikipedia/commons/e/e2/Protein_mosaic.jpg

A protein mosaic, providing an insight on the complexity of proteins. Image Credit: Astrojan

When the proteins and RNA were joined together at the start of life, the mechanisms for construction through transcription, translation, and replication must have co-evolved. With this concept in mind, the researchers found commonalities between compounds similar to evolution from a common ancestor. Thus, with these concepts in mind, when looking at molecules we can find an evolutionary chain to see how molecules developed to be what it is today and also why they developed this way.

Finally, to answer the “chicken and the egg” debate, it is likely to be both like an Oyako-Don (mother-child bowl), a Japanese dish that harmonize chicken and eggs. Life as we know it was likely developed through a combined effort of RNA and proteins.

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Posted on September 24, 2018 by in Biological Sciences, Science Communication

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