Tag Archives: biology

Alzheimer’s disease: An Irreversible Brain Degeneration

Alzheimer’s disease was first discovered back in 1906 by Dr. Alois Alzheimer. It is a degenerative brain disease which is predicted to effect up to 5 million people in the US alone. This disease effect an individual’s cognitive ability, emotion, behavior, physical abilities, and could ultimately lead to death. The following video provides a summary of the Alzheimer’s disease:

https://www.youtube.com/watch?v=9Wv9jrk-gXc

Even though this disease was discovered for over a century ago, scientists around the world are still unable to fully understand or discover any cure for the disease. However, they found traces of two forms of proteins known as ‘Plaques’ and ‘Tau’ protein which is believed to be associated with Alzheimer disease.

Normal brain and a brain with Alzheimer's disease

Healthy brain Vs. Brain with Alzheimer’s disease – Plaque and Tangle proteins. <http://neurowiki2012.wikispaces.com/Down+Syndrome>. Photo credit: Jefferson Hospital.

Plaque protein are created from smaller proteins that sticks together and form a clump shape, this protein may block the connection between nervous cells and interfere with the communication network in our brain. In some cases, our body detects that the cell cannot function normally and hence our body started to destroy our own cells. Another protein associated with Alzheimer disease are called ‘tau’ protein, a protein that involved in the process of transporting nutrients to nervous cells. In Alzheimer patients these proteins collapse and form another form of non-functioning protein known as ‘Tangles’ protein. This results in the lack of nutrients being transported to the cell leading to cell death. Both of these abnormal form of proteins interferes with the nervous system in the brain and causes several of symptoms associated to Alzheimer.

“You lose your memory. Step by step, you turn into a person you don’t know anymore. And the one you knew disappears.”- Richard Taylor, Former psychology professor, Alzheimer patient.

Symptoms of Alzheimer's disease

Symptoms of Alzheimer’s disease. <http://www.doc-advice.com/alzheimers-disease/>.

Due to the facts that this disease targets the nervous system especially in the brain the symptoms may involve the loss of memories, abnormal behavior and changes in personality. The disease will slowly move from one region of the brain to another, along the way it kills nerve cells and started to alter the brain function. It can be seen that as the disease migrate throughout the brain, different symptoms will start to emerge, from unable to form normal speech to emotional control, hallucination, memories lost, the inability to perform everyday tasks and ultimately destroying the regulatory region of the brain leading to death.

“Most people are aware of the problem— I hope — but I don’t think people get just how serious Alzheimer’s is until it happens to somebody they love, and that’s happening more and more.” – Dr. Christopher Ochner, Ph.D. clinical psychology, Columbia University.

Personally, I think Alzheimer’s disease is extremely dangerous and a worldwide threat. It’s a disease that does not only affect one individual but the whole family. More scientific funding is required for research in this field. To prevent the death toll from rising due to Alzheimer, it is crucial for the cause and a cure for this disease to be found.

Shortcuts to Weight Loss: The Risk-Benefit Analysis of Weight Loss Supplements

With the busy lives that humans now occupy within society, like post-secondary students during exam season for example, balanced and nutritional dietary and exercise are often disregarded or not of a major priority. As a result, the body begins to accumulate fats to act as a storage for excess energy from the foods we eat and thus leads to a case in what society would call “overweight”. The extreme case would result in obesity and this has been a growing concern (and a rather sensitive topic to some) over the past years because excessive body weight is associated with various cardiovascular diseases, diabetes, asthma, and overall, a reduction in life expectancy. However, there is one suggestion that is portrayed by media and human society that is supposedly a shortcut to this problem: weight loss supplements.

Weight loss supplements contain common active ingredients such as bitter orange (synephrine), chromium, guar gum, and Hoodia(1). Synephrine, the main composition of bitter orange, works to suppress appetite and increase the rate of metabolism, thus increasing the number of calories burned (1). Chromium is a mineral that helps to regulate insulin and helps promote muscle growth and fat reduction and guar gum helps block absorption of fats in the body and increase the feeling of fullness whereas Hoodia temporarily suppresses your appetite (1).

Although these active ingredients and their functionality seem to be the solution to obesity, there are many side effects. First of all, synephrine is very similar to ephedrine (see Figure 1), a banned stimulating drug by the Food and Drug Administration due to implications with stroke, heart attacks, and hypertensions, in chemical structure and have many similar characteristics (2).

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Figure 1: Chemical structure of synephrine compared to ephedrine

Secondly, although chromium exists naturally in our bodies and certain foods, the intake of excessive chromium is disadvantageous because chromium, like other heavy metals, is rather toxic to the human body even at low concentrations. Moreover, although guar gum and Hoodia (Figure 2) work in synch to suppress the production of fats for excessive energy storage as a result from eating food, the overall results are still not proven and can potentially lead to malnutrition (1).

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Figure 2: Chemical structure of guar gum (top) and Hoodia (bottom)

To note, a research by Eichner, Maguire, Shea, and Fete have determined that many weight loss supplements are still on the market today that contain other ingredients that are banned due to psychiatric issues and complications with the cardiovascular and nervous system (3). Other ingredients that are not banned but are subject to caution and consumer knowledge are also present in many weight loss supplements(3).

In conclusion, although shortcuts are available to everyday medical conditions such as obesity, there are also many drawbacks to such methods. The optimum method would be the natural method of weight loss which involves a balanced nutritional dietary and exercise, despite how busy our lives may be or what telemarketers or advertisements tell you.

-Andrew Siu

References

Eichner, S., Maguire, M., Shea, L.A., and Fete, M. Journal of the American Pharmacists Association 2016, 5, 538.

Fitday. How do weight loss pills work in the body?  http://www.fitday.com/fitness-articles/fitness/weight-loss/how-do-weight-loss-pills-work-in-the-body.html (accessed Oct. 31, 2016).

Google Patents. Pharmaceutical compositions having appetite suppressant activity. http://www.google.com/patents/US7166611 (accessed Oct. 31, 2016)

Nutrient Journal. Is bitter orange fruit (citrus aurantum as synephrine) new ephedra? http://nutrientjournal.com/is-bitter-orange-fruit-citrus-aurantum-as-synephrine-new-ephedra/ (accessed Oct.31, 2016).

Sci-Toys. Guar gum. http://sci-toys.com/ingredients/guar_gum.html (accessed Oct. 31, 2016).

Mad Cow Disease: An Inevitable Death

A disease that has no cure and leads to an inevitable death. ‘Mad Cow Disease’ was first discovered in United Kingdom back in 1986, and for nearly 15 years the outbreak has infected up to 180,000 cattle and damaged many farm communities in the area.

Mad Cow Disease is also known as ‘Bovine spongiform encephalopathy (BSE)’, which the name itself suggests a spongy form of the cow’s brain. BSE is a slow progressing disease which targets the central nervous system of the cow causing it to act abnormally and eventually lead to its death. For unknown reasons a protein, known as ‘prion’, located in the brain of a cow, starts to change its conformation. This creates a signal which changes the conformation of other prions like a chain reaction and leads to the slow degradation of the brain. The following video provides a summary of the mad cow disease:

https://www.youtube.com/watch?v=aP-ShyyHiIc
“Mad Cow Disease is an infectious disease of cattle transmitted but by virus or bacteria, but by an abnormal form of type of protein called a prion”- Dr. Linda L. Walsh, Dept. of Psychology, University of Iowa

Transmission of this disease to human will lead to certain death, although the time length for each cases can vary from about 6 months to many years. The form of mad cow disease infected in human is known as ‘variant Creutzfeldt-Jakob Disease’ or vCJD.

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Structure of normal and abnormal prion protein, and its effect on human brain. http://www.viviennebalonwu.com/2015/07/creutzfeldt-jakob-disease-cjd.html.

This disease causes a slow degradation of the brain, creating small holes, and destroying the nervous system. As such, the symptom of this disease may consist of memory lost, lack of coordination, personality change, psychiatric issues, movements, speak and death. The transmission of this disease occurs from the direct consumption of meat infected with the abnormal prions, and possibly from blood transfusion.

“Another risk is the spread of vCJD through blood transfusions – and it is still not known exactly how many people are carriers of the disease.”  – Professor Graham Medley, University of Warwick

Although, many countries started to separate the brain, and other parts of nervous system, from the main food supply after the outbreak in the late 1990. It is possible that there are infected people who are unaware of it. Thus it increases the risk of transmitting this disease to others via blood transfusion.

“We are pretty sure that there are people out there who are infected but don’t have the disease”Professor Graham Medley, University of Warwick

Personally, I feel that there is a higher demand for research regarding prions and a cure for mad cow disease. The cause for this disease is still unknown and because of this, it is extremely difficult to prevent an outbreak from happening or to protect people against it.

 

Poramat Sucharit

DNA Evidence – Not so airtight after all

March 2009. Police departments across Europe have been searching for a serial killer known as the Phantom of Heilbronn. Her DNA had been found at crime scenes all over the subcontinent. Other than the DNA, police had no other clues to her identity. Finally, a break, but not exactly what authorities were looking for. They had found an individual with matching DNA, only it was a man. Stumped as to how their profile was matching to a man – a genetic impossibility – investigators re-examined the evidence. They eventually determined that the Phantom of Heilbronn was just that, a phantom. The DNA belonged to a worker in the factory that manufactured the cotton swabs used by the forensic officers. The swabs had contained minor contamination from the worker, but had been used to collect samples at crime scenes. When analyzing the swabs, investigators found the DNA profile of the worker, instead of that of the culprit.

Every cell with a nucleus contains molecules of DNA, which function as the blueprint of life. Cells read the code in DNA and use it to construct and operate the body of the organism. Humans share 99.9% of their DNA sequence, but there is variation in the code. Modern technology can read an entire DNA sequence and isolate the parts in which there is known to be variation, known as loci. The variation at all loci produces a DNA profile that is as unique to an individual as a fingerprint. Forensic analysts working with police departments then use this to match a suspect’s DNA to that found as evidence at a crime scene.

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How DNA analysis works. Source: The National Forensic Science Technology Center (NFSTC)

Media and popular culture would have you believe that DNA fingerprinting technology is infallible. As the case of the Phantom demonstrates, it most certainly is not. Since with modern technology DNA can be extracted from only a few cells, post-crime contamination during crime scene handling is becoming increasingly problematic. Cells from anywhere or anyone can end up on pieces of vital evidence and be misidentified as the cells of the criminal. Sometimes, as in the case of the phantom, this wastes valuable time and resources. Other times, such as in the controversial Amanda Knox case, it can land the wrong person in jail.

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Crime scenes are at high risk of DNA contamination  Source: Wikimedia commons, By Tex Texin from Blogosphere, Cyberspace – “Crime Scene Do Not Cross” tape, CC BY 2.0

Crime scene contamination, along with other ways DNA evidence can be corrupted, cast doubt on the perceived faultless technique of DNA fingerprinting. Sometimes, even if with a DNA match cannot prove guilt beyond a reasonable doubt.

Megan Wolf

Bacteriophages: A Possible Alternative to Antibiotics?

What would happen if we ran out of antibiotics to use against bacteria? Antibiotic resistance is known to be one of the major concerns among doctors and scientists around the world since, it’s our primary defense against bacterial infections. Without these antibiotics, it’d be virtually impossible to treat many types of diseases or even perform surgeries.

The quality of healthcare has significantly improved over the centuries as more people have access to treatment, medicine, and antibiotics. However, it has also increased the risk of wrong applications of drugs, allowing the bacteria to develop defense mechanisms to different types of antibiotics. In fact, there has been a dramatic increase in the number of scientific reports about different drugs resistance cases.

Antibiotic resistance occurs through process known as ‘Natural Selection’, where the bacteria has evolved and is no longer affected by the antibiotics. A stand-out candidate as an alternative for antibiotics is known as bacteriophages.

‘Alternative treatments are urgently required and we are investigating one such treatment – the use of bacteriophage.’

  • Robert Atterbury, Phage Biotechnology, University of Nottingham.                             
Resistance bacteria survived the treatment of antibiotics, thus able to reproduce and increase in numbers.

Resistance bacteria survived the treatment of antibiotics, thus able to reproduce and increase in numbers. <http://www.reactgroup.org/toolbox/mutation-and-selection/>. Photo credit: Uppsala University

‘Bacteriophage, or phage is a virus that infects bacteria, so these don’t infect human cells- they are specialised and only infect bacteria’

  • Brent Gilpin, Science Leader, Environmental Science Group, New Zealand.
Bacteriophage attached itself to the bacteria before releasing its DNA inside.

Bacteriophage attached itself to the bacteria before releasing its DNA inside. <http://www.news-medical.net/news/20151202/Bacteriophage-therapy-an-alternative-to-antibiotics-An-interview-Professor-Clokie.aspx>. Photo credit: News-Medical.net team

Bacteriophage or phage infects the bacterial cell by first recognizing the bacteria and then attaching itself to the bacteria’s surface (cell wall). After the phage has penetrated the cell wall, entering the bacteria, and it releases its DNA inside. This DNA merges itself with the bacterial DNA causing the bacteria to produce proteins for the phage. Other chain reactions occur which causes the bacteria cell to produce more phages and eventually bust out, causing the bacteria to die. – This process is shown in the following video:

‘Bacteriophage Life Cycle’

This method is currently being adopted by many industries including food protection against food-borne disease, and medical treatment for both animal and humans. Furthermore, there are many advantages in using phage therapy; for example the phages are target specific, thus only attacking bacteria with a certain structure. With the right phage, it’s harmless to humans and since, phage is found naturally throughout the environment, there are several types of phages that can be studied and used. In addition to this, phage can be genetically modified to reduce their side effects, harmful abilities, or any unnecessary features. With this, it’s possible that phages can be used as an efficient and effective treatment against bacteria.

I strongly believe that bacteriophage is a potential alternative for antibiotics due to its ability to target specific bacteria, its harmless nature to humans, and its ability to be genetically engineered. Moreover, it can also be used in many industries as a safety precaution, in medical treatments, or even scientific research.

 

Poramat Sucharit

The Defense Mechanism of Plants

Close your eyes and imagine your sun soaked skin embracing the warmth Vancouver has finally blessed you with, the gentle cool breeze dancing through your hair, and your feet standing on top of a luscious, emerald lawn. Go ahead, take a deep breath, the smell of freshly cut grass. The scent of summer.

Why is the scent of freshly cut lawns so pleasant? The answer is pheromones. Plants are able to communicate with each other by sending out pheromones—chemical messengers. Plant cells synthesize these chemical compounds and then release them into the environment to elicit a response in the times of distress.

One of the key chemicals that elicits the defense response in plants is Jasmonic Acid. This organic compound activates the production of other genes for defense.

Methyl Jasmonic Acid is a derivative of jasmonic acid; its role is to regulate the developmental process and defense responses of plants when stress is detected. Part of the defence mechanism is releasing pheromones into the air warning plants around them that danger is near. These pheromones released are organic volatile substances known as Green Leaf Volatile (GLV). They have aldehydes, alcohols, and ester functional groups, which produces that fragrant aroma that people so often associate with summer.

Volatile Organic Compounds       Credit: Materic, D. et al. phys.org

Methyl Jasmonic acid is synthesized through the octadecanoid pathway. The picture below shows a detailed reaction pathway to this compound.

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Biosynthesis of Methyl Jasmonic Acid        Credit: Cheong, J.J. and Choi, Y.D. , Trends in Genetics

Although these volatiles may come from the same or entirely different species, the presence of these chemicals increase defence compounds. When cell membrane receptors detect these volatile chemicals, it activates self-defence by producing toxins, such as proteinase inhibitor. Furthermore, some of these pheromones produced by plants are able to attract insects to help defend themselves. For example, some plants release a certain type of pheromones to attract wasps. These wasps lay their eggs in caterpillars and when these eggs are hatched, the larvae eat the caterpillar from inside out.

I find this defense mechanism of plants absolutely fascinating. Plants are able to defend themselves in certain ways humans and animals cannot. While animals have physical features such as sharp talons or claws, speed, enhanced senses, and humans have martial arts and the sympathetic nervous system that elicits the fight-or-flight response as a form to defense mechanisms, plants defend themselves with the power of chemistry!

So the next time you’re out on a stroll enjoying that summer evening and you hear the roar of your neighbour’s lawnmower, you now know that the fragrant cut grass scent that follows is actually their distress signal. While releasing a series of organic molecules into the air to warn their plant friends and neighbours, it serves as an aromatic treat for us humans.

This video provides a more general explanation of this topic:

Resources:

Reece, J.B. et al. Fundamental of Physiology, 2nd ed.; Pearson: Canada, 2014; pp 237-238.

Cheong, J.J.; Choi, Y.D. Methyl jasmonate as a vital substance in plants. TRENDS in Genetics. [Online] 2013, 7. 409-412. http://www.cell.com/trends/genetics/pdf/S0168-9525(03)00138-0.pdf (accessed Sept 23, 2016)

Phys.org. De-mystifying the Study of Volatile Organic Plant Compounds. http://phys.org/news/2016-01-de-mystifying-volatile-compounds.html (accessed: Sept 24, 2016)

Rio’s Emerald Pools: A Scientific Whodunit

This summer, when I tuned in to the Rio de Janeiro Olympic games and saw cloudy green waters in the diving pools, I barely batted an eye. I thought this was merely a media stunt. The Brazilian authorities had harmlessly dyed the waters green because it fit with the country’s theme. They have a green flag, they have incredible natural greenery and so on. I soon learned that this was no dye. The waters had, seemingly spontaneously, turned green overnight.

The games’ organizers pointed the finger at an unnamed stadium worker who apparently poured copious amounts of hydrogen peroxide into the pool. Possibly this was an attempt to “super-sterilize” the pool, akin to using peroxide on a skinned knee? However, like most swimming pools, this one had already been treated with chlorine. More specifically, sodium hypochlorite (NaOCl). When NaOCl is combined with water it forms hypochlorous acid, a potent antimicrobial agent. Adding hydrogen peroxide to the mix would have reacted with the chlorine-containing NaOCl in the pool, producing NaCl, O2 and water. As NaOCl is added to kill microbes such as algae, its absence allowed them to proliferate and fill the pool.

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source: BBC sports

According to a recent article  in the C&En News, this response has been refuted by chemists and biologists alike. It seems impossible (or, in science terms: highly improbable) that the algae could reproduce so quickly to muddy the pool overnight. Some scientists believe it was a chemical reaction resulting from the addition of copper-containing antiseptic chemicals in improper quantities. In the presence of chlorine, copper forms a green complex. This theory even accounts for the smell reported by athletes: hydrogen sulfide, which is a by-product of this reaction.

Solutions

Which solution is THE solution?                                  Image Courtesy: Leiem, Wikimedia Commons

As the Newscripts article reports, we will never know the true solution to this chemistry mystery. All pool water, and potential analytic samples, has long gone down the drain. Nevertheless, chemists will always remember the time when their discipline had its moment in the hot Brazilian sun.

– Megan Wolf