The Magic of Aspirin: Uncovered

Posted on October 16, 2017 by | 2 comments

Ever have a headache ? fever ? you’ve probably have taken  aspirin or acetyl salicylic acid in your life. Aspirin has been used by humans for more than 2500 years ever since someone had discovered that chewing willow leaves treat the discomfort. This is because of salicin which is turned into salicylic acid in the body allow for the discomfort to be treated. Chemists such as Charles Frederic Gerhardt and Felix Hoffman experimented with salicylic acid to make it last longer and make it less toxic in the body which lead to the creation of aspirin or acetyl salicylic acid. Most people have taken aspirin and enjoyed the comforts it brings in terms of fevers or headaches. But how does aspirin actually work in the body ?

 

Salicin the compound found in Willow leaves initially used to treat headaches , fevers and inflammation Attribution: Wiki Images (https://upload.wikimedia.org/wikipedia/commons/a/ab/Salicin-2D-skeletal.png )

 

Chemical structure of Aspirin ( Acetyl Salicylic acid ) Attribution: Sigma Aldrich http://www.sigmaaldrich.com/content/dam/sigma-aldrich/structure1/180/mfcd00002430.eps/_jcr_content/renditions/mfcd00002430-large.png

The body has many ways to fight an infection it could cause a fever by raising the temperature and allow the pathogens to die , it can generate immune cells to generate chemicals in order to fight pathogens and infections or they can generate other chemicals recruiting other immune cells as backup. The body has natural ways of dealing with pathogens and bacteria. Hence , aspirin should only be used when the fever is lasted longer than expected or the body temperature is fairly high. In 1971 , the discovery of the chemical prostaglandin was found to be responsible for fever , pain and inflammation. Aspirin treated these symptoms by preventing the release of prostaglandin. Prostaglandins are produced in various forms and their functions include but are not limited to  increase of body temperature , stimulation of immune cells , initiation of blood clotting and much more. Prostaglandins are released from an enzyme known as Cyclooxygenase or COX. An enzyme is a chemical substance which increases the speed of a reaction. Most enzymes require a missing piece , known as a substrate , this substrate binds to the enzyme and activates it in order to speed up the reaction taking place. Cyclooxygenase’s substrate is known as Archidonic acid , when this substrate binds to the enzyme it releases prostaglandins so they can act on the body and cause inflammation , pain and a rise in temperature.

The production of prostaglandin from the enzyme COX Attribution: Wiki images  https://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Prostaglandin_E1.svg/1486px-Prostaglandin_E1.svg.png

When you take aspirin or acetyl salicylic acid , it binds to the enzyme COX              (cyclooxyengease) and prevents its substrate (Archidionic acid) to bind. The acetyl salicylic acid binds irreversibly , meaning that it does not unbind easily and requires energy for it to unbind from the enzyme. The loss in production of prostaglandins results in less inflammation , pain and fever.

Summary of Aspirin blocking the enzyme COX irreversibly Attribution: Slide share https://image.slidesharecdn.com/cox-170117123110/95/nsaids-cox-enzymes-physiologyand-pharmacological-modulation-20-638.jpg?cb=1486012928

However , prostaglandins are also responsible for blood clotting and if they are blocked from being produced , blood clotting will not occur as effectively. Aspirin should be taken with care and only when required. Other medication such as acetaminophen (Tylenol) or ibuprofen (Advil) are a better substitute in the case of the fever or body temperature not being as high. Some people might think an alternative to medication are “natural” remedies that directly arise from plant based foods. They tend to forget that medication is synthesized from plants. I believe that medication is the way to go for the best treatment of most type of illness. So next time you take an aspirin you can be thankful for that willow plant someone ate a few thousand years ago !

– Garvit Bhatt

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Air Pollution Also Causes Stress: Should You Worry?

Posted on October 16, 2017 by | 1 comment

Two months ago, there was a large scare as Chinese researchers found that a common air pollutant, PM2.5, not only causes lung and heart disease but increases stress as well.

Kan and Chen modified the air purifiers in select dormitories in Shanghai so that half of them could reduce PM2.5 levels and half couldn’t. Then they monitored the level of homones in the students’ bloodstream after nine days. Surprisingly, they discovered an increase in stress hormones such as cortisol for students who lived without air-purification.

Chemical structure of cortisol. Wikimedia Commons: Foobar. https://commons.wikimedia.org/wiki/File:Cortisol.png

This study was conducted on students in Shanghai, but PM2.5 is the most dangerous air pollutant to us in BC as well. PM2.5 are particulate matter (solid and liquid particles in the air) smaller than 2.5 micrometres. Their small size allows easy access into our lungs to cause chronic lung and heart disease along with increasing stress as mentioned above.

Should we worry though? While Chinese cities largely exceed the World Health Organization limit for PM2.5 at 10 micrograms per cubic metre, Canadian cities are all under this limit.

Figure 1. Comparison of PM2.5 levels in Vancouver, Toronto, Hong Kong and Shanghai. Note that the Canadian cities have PM2.5 levels below the WHO limit of 10 micrograms per cubic metre. For clearer image, see BP 2

In this graph above, it shows that Vancouver is below this limit and busier cities such as Shanghai are five times this limit. Toronto is nearing the limit, but there was a decreasing trend for Toronto in 2015 and no trend for BC.

Unfortunately, this means that your stress isn’t caused by this air pollutant.

Fortunately though, the PM2.5 levels in BC are still safe. But you still need to take personal steps to reduce the impact of air pollution on yourself and others.

Simple steps to stop producing PM2.5 are to stop driving, smoking, and burning wood as these are the highest sources of PM2.5 in BC. Take alternative transport, use alternative fuel to warm your homes, and just don’t smoke. In fact, smoking will increase your chances of lung and heart disease way more than breathing in PM2.5 will. Others will be also be harmed more by breathing in your tobacco smoke than by breathing in PM2.5.

And if you don’t smoke, exercise outside! Open the windows when you’re studying, and take in the clean air that you are gifted to have.

-Ivy Wu

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Perfumes: Invisible Hazards

Posted on October 15, 2017 by | 4 comments

How often do you use air fresheners, candles, or perfumes at home? A lot of people love using perfumes when they go out, and air fresheners and candles to get rid of unpleasant smell in their homes. But, have you ever thought about where those chemical substances go?

The researchers from The York University in UK have discovered that level of limonene, which is the main source of citrus scent in perfumes and air fresheners, was significantly high in homes that use perfumes. Limonene is a common substance that also exist in foods we eat, and is not harmful to our health. However, the problem occurs when limonene reacts with ozone, which is part of the air we breath in. The limonene reacts with ozone to produce formaldehyde.

Limonene react with ozone to form formaldehyde copyright-created by Diana Kim

Formaldehyde is named as a known human carcinogen. Ozone is also present indoors, with higher level when we use electronic devices. Therefore, when we use perfumes at home, it is likely that the limonene will turn into hazardous carcinogen in the air. The research also has mentioned that higher concentration of limonene in the air means there are more possibilities that it is going to turn into formaldehyde. It is better to use perfumes in an open space, with windows opened to let the substances out.

To minimize the exposure to formaldehyde in your home, it is the best to ventilate home regularly. Also, having air-filtering plants at home helps getting rid of formaldehyde in the air. The air-filtering plants, such as garden mum, spider plant, dracaena, ficus, and peace lily, absorb formaldehyde in the air.

https://commons.wikimedia.org/wiki/File%3APeace_Lily.JPG

Although scents can help stabilize our emotions and therefore can be good for our mind and gets rid of unpleasant smell immediately, we would have to think more about how it can harm our health directly.

 

-Diana Kim-

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Psychedelics… Not Just for Hippies Anymore

Posted on October 14, 2017 by | 1 comment

“Never do drugs!” Constantly, throughout childhood and adolescence, it is drilled into our brains that drugs will ruin our lives. However, new research is indicating that some drugs may be a positive influence in many aspects of our mental health. No, I’m not trying to tell you that shooting heroin or snorting cocaine will cause you any benefit. But, when clinically mediated, use of hallucinogenic (psychedelic) substances such as lysergic acid diethyl-amide, LSD (colloquially known as acid), and psilocybin, the active chemical in “magic mushrooms”, may lead to a healthier perspective on life. But how can illegal drugs offer any benefits?

An artist’s rendition of the mindfulness experienced during an acid (LSD) trip

Can you tell me a time that you’ve felt not as a human, but as an internal cog in a non-definitive life force that extents through you? Experiencing an unfathomable connection between your soul and each fibre of every living thing on the Earth. For an instance, you understand that your reality is a nothing but a tribute to life itself. The answer for most: “of course not, I’m not crazy..?”. This is how I would best describe the awe-inspiring  experiences I have had with the mind-reviling effects of psychedelics. No, I’m not insane. But these experiences have changed the way I view the world, amplifying my appreciation of life, and allowing me to see existence in a new and humbling way.

Chemical structure of LSD

Now my claims may seem outlandish, but studies at Imperial college London have illuminated the therapeutic mind-expanding effects of psychedelic drugs for those with depression, addiction, death anxiety, PTSD, and even for the general public. As world renowned psychedelic drug researcher Dr. Robin Carhart-Harris explains in interviews with CNN and presentations with TEDx: “This experience is sometimes framed in a religious or spiritual way — and seems to be associated with improvements in well-being after the drug’s effects have subsided”.

With the use of modern brain-imaging technology, Dr. Carhart-Harris is attempting to reduce the public stigma on these kinds of drugs.  MRI brain imaging scans, when compared to a placebo, have displayed a mind ‘lit up’ with unified activity under LSD conditions. Results of mindfulness questionnaires, taken by LSD users in the same study, emphasize a sense of openness and optimism while experiencing the drug’s effects.

MRI scans from Dr. Carhart-Harris’ study. This image reveals that, with eyes closed, much more of the brain contributes to a unifed visual experience under LSD conditions than with a placebo.

 

This area of study is young. Extensive research is required before LSD and psilocybin are removed from the dangerous drug index. Education is vital for people to understand the benefits these drugs can offer. I believe the improved respect for Earth and all its organisms may be the key for peace for those effected with mental illnesses and a cure for the hate that is far too present in society today. Through my personal experiences, I can assure that psychedelics facilitate beneficial reshaping of your way of thinking. In turn, these substances could create a more positive, harmonious world with acceptance and contentment through revised perspectives.

Joey Krahn

 

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Does whey protein really effect kidney?

Posted on October 2, 2017 by | 4 comments

Does whey protein really effect kidney? This is a commonly ask question when people are talking about fitness and weight loss. People with different idea keep arguing with each other. So what does whey protein actually do and how is that gonna affect our body?

chocolate whey isolate protein

General types of whey protein.

Whey protein is a mixture of beta-lactoglobulin, alpha lactalbumin, bovine serum albumin, and immunoglobins. There are three primary types of whey protein:

  1. Whey protein concentrate: WPC contains low level of fat and carbohydrates and some minerals. The concentration of protein is usually 25-98% (Typical level found in commercial products is ~80%)
  2. Whey protein isolate: WPI contains 90-95% of whey protein and only trace amount of fat, lactose and minerals.
  3. Whey protein hydrolysate: WPH, also called hydrolyzed whey, is the partially hydrolyzed whey protein which is much easier to be digested and absorbed than the other two. This type of products usually contains 80-90% proteins.

How does it work?

Protein is vital to our body function. It helps the cells grow and repair themselves, and compose much of the actual substance of human body. Human body can synthesize some protein itself from 12 amino acids produced itself. The other 9 amino acid must be gained from dietary protein and whey protein is one effective source which works in the same way as an egg or steak does. However, human body absorbs whey protein much faster than from daily foods.

The benefits!

  1. Weight loss: A study done in 2008 published in Nutrition & Metabolism evaluated the whey protein for use as a dietary supplement to enhance weight loss. The result shows that the group which is given whey protein lost significantly more body fat than the group consuming control beverage.
  2. Reducing cholesterol level: A study done by  Sebely, Vanessa and Satvinder supplied 70 overweight men and women with whey protein for 12 weeks and measured the lipid and insulin levels regularly. They found that there was a significant decline in total cholesterol and LDL cholesterol comparing to the control group.
  3. Lowering blood pressure and reducing the risk of cardiovascular disease: A research done by Susan et al. shows that whey beverages significantly reduced blood pressure in patients with hypertension and also their risk of getting heart disease was also lowered.

Any negative effect?

Whey protein is derived from milk so people who are allergic to milk may also be allergic to whey. Usually, whey protein doesn’t cause any health problem except for excessive consumption. It will cause stomach pains, nausea, headache and so on. When too much whey is consumed, the kidney faces a big challenge of excreting the waste and may cause impaired function of kidney. A moderate amount of whey intake is 0.8 grams per kilogram of body weight.

Back to the question: Does whey protein really effect kidney? The answer is Yes and No. Moderate consumption of whey protein along with resistance exercise will not cause any healthy issue and will help muscle building and metabolism. However, overdoes of whey protein will definitely cause kidney problem like kidney stones.

Written by Xuan Wang

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Who Takes the Responsibility of Food Coma?

Posted on October 2, 2017 by | 2 comments

We’ve all been there. After lunch, you are sitting in class with overwhelming drowsiness. This feeling has a terminology called “food coma” which is a state of drowsiness or lassitude following a meal. The reason that causes food coma has been studied for many years, and scientists are still researching it and having arguments.

Food coma after a meal.

A popular statement is that the food coma after eating is related to amount of carbohydrates in the meal. Meals that are high in carbohydrates cause an increase in the hormone insulin. The ensuing high level of insulin promotes large removal of the branched-chain amino acids by muscle, thereby lowering the plasma levels of these amino acids. As a result, the entry of branched-chain amino acids into the brain is reduced, while more tryptophan enters the brain. Tryptophan is a special amino acid that in the brain can be converted into a signalling chemical called serotonin. Serotonin is associated with feeling of  sleepiness and drowsiness. The more Serotonin existed in brain, the stronger drowsiness you will feel.

Pathway from Tryptophan to Serotonin. 

A study in fruit flies sleep patterns discovered that, just like us, they slept longer after large meals, and there were some foods that were much better at letting them sleep than others. The research also reveals that salty or protein-rich foods promote sleep, whereas sugary foods do not. In their experiment, feeding high-protein and large meals to the fruit flies caused them to sleep up to 40 minutes more than they usually would if they hadn’t eaten anything. And high-salt meals increased the fruit flies sleep period by nearly the same amount. High carbohydrate meals, however, did not change the flies’ sleep patterns in comparison with their sleep patterns after not eating. The researchers found that specific brain circuits are likely to cause the desire for post-feast naps. The food coma effect is weaker or stronger at a different time of the day. For the fruit flies, the effect is stronger in the morning than in the evening. This indicates that the body’s internal clock also plays a role in a time when we are most likely to feel sleepy after a meal, especially after lunch.

More research will be happening to study what is the major reason that causes food coma. It will then give us a direction on how to adjust our dietary habits for diminishing food coma after a meal. Hope that day will be coming soon!

-Olivia Yang-

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Did Martian gave hope to young explorers ?

Posted on October 2, 2017 by | 1 comment

Whenever a new science fiction movie comes out, there’s often a lot of talk about how “accurate” it is, and this is usually in reference to the science: Can dinosaur DNA really come from a preserved mosquito? Can an asteroid really be deflected with a nuclear bomb?Usually, the scientific content of these movies is inaccurate, as movie directors try to engage in fantasy by having monsters and magic.  If it doesn’t involve post-apocalyptic scenes of zombies invading the Earth, it is not appetizing for the over-demanding audience.  With this in mind, “The Martian” might be one of the most accurate movies in terms of scientific content. However, it still exaggerates many aspects related to agriculture and fails to mention the reality behind trying to grow plants on Mars.

Farming on Mars

In the movie, after becoming stranded on the surface of Mars, Watney resorts to using a combination of his excrement, water, and Martian soil to grow potatoes. But is this realistic? Could the Martian soil be of any use? Isn’t it sterile and dead?

In terms of basic mineral content and chemical content, yes, it would be possible to grow plants in the Martian Soil. In fact, scientists conducted research on the chemical composition of rocks from Mars. They found that mars contained many bio-elements such as Potassium, Calcium, and Iron. Scientists claim that the rocky material on Mars is fertile and has the potential to yield extremely productive soils.

Well, kudos to the director for getting these facts right but Hang on! Is using human excrements even safe? No, it is not. Many studies show that using excrements could result in major health problems. It could spread disease and have a serious impact on human health.

 Water Availability  

Matt Damon’s character took hydrazine from the rocket and dissociated it into nitrogen and hydrogen. He then mixed the hydrogen with oxygen to make water. This process is doable if I was an expert on how to extract fuel and knew basic chemistry. It could certainly work but if I was stranded on Mars, I will just make water out of the soil. Water is available in its natural state on Mars as ice, permafrost or soaked into the soil. Martian soil is about 5% water. by weight, at low latitude and up to 60% water near the poles. Martians are not going to get their water by importing hydrazine and burning it with precious cabin oxygen, they are going to find it in the soil!

The Martian was a great movie in terms of depicting scientific content. It succeeded in inspiring young people to consider the possibility of conquering space. However, before you pack your bags and move to Mars, you must know that surviving on Mars could be a struggle. Even though the elements of life might be available on Mars, trying to sustain human life will be a challenge.

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Everything is okay… In moderation.

Posted on October 2, 2017 by | Leave a comment

I want to teach you about an interesting little molecule called 2,4-dinitrophenol that is capable of uncoupling the most important cellular process in your body.

Image result for 2,4-dinitrophenol

2,4-dinitrophenol is a compound that was discovered in the 1930 and for a brief time was sold as a diet pill due to its weight loss effects. When DNP is ingested orally, it finds its way into the mitochondria, positioning itself in the Inner Mitochondrial Membrane. The hydrogen of the phenol is easily deprotonated, the molecule essentially acts as a proton shuttle, moving protons from the intermembrane space to the mitochondrial matrix, by constantly getting protonated and deprotonated. This action is absolutely devastating for the cell because it is effectively uncoupling the Electron Transport Chain from Oxidative Phosphorylation.

Image result for mitochondria

For those of you who may need a small refresher, cellular respiration starts with the breakdown of glucose into electron carriers, which enter the mitochondria to get oxidized in the Electron Transport Chain, causing protons to be pumped into the IMS, creating a proton gradient. These protons are the driving force for the enzyme complex ATP synthase, which ultimately converts ADP to ATP in the matrix. If there is no gradient in the IMS, ATP synthase won’t be able to generate energy for the cell.

When an individual consumes DNP, the reason they lose weight is that as cellular respiration becomes less and less efficient (due to the loss of the proton gradient), the body starts burning more and more fuel in an effort to meet the energy demands of the cell, causing weight loss. So what’s the downside? Well, all the energy that should be going into ATP production ends up being lost as heat, which raises the internal core temperature to lethal levels.

Interestingly, as bad as this sounds for you, the body actually has its own version of this molecule, which is crucial in the thermoregulation of newborns. All mammals have a type of cell called Brown Adipose Tissue (BAT) present mostly in newborns and hibernating animals, but adults also have a small quantity in their bodies. Brown fat is brown due to an increased number of mitochondria, which contain a special protein called thermogenin, located on the inner mitochondrial membrane.

Thermogenin is an uncoupling protein because its function is to uncouple the ETC from oxidative phosphorylation much in the same way DNP does. By opening a proton leak channel in the membrane and decreasing the proton gradient, heat is generated and the core temperature increases. It is especially important for the thermoregulation of infants because they don’t have any other mechanisms at their disposal to regulate their own temperature. They have little hair, not very much skeletal muscle for shivering and of course they can’t just put on a sweater!

Image result for brown adipose tissue

Thermogenin (UCP1) and the role of BAT on metabolic rate are being explored as a possible treatment or therapy for obesity. 

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Trump and science: How US new travel bans affect scientists and their research

Posted on October 2, 2017 by | Leave a comment

Science is one way for human beings to interpret and develop the world, and politics is another way, yet it is time to notice science and politics are no longer running in parallel. In the US, politics is affecting science and harming science progresses.

Since the beginning of this year, Donald Trump issued and revised policies limiting immigration from Muslim-majority countries. Following Nature’s reports, travel bans have negatively impacted scientists and their researches in and outside of the US. Active and future scientists faced extreme travel difficulties, and a few international science conferences and collaborations were canceled or delayed due to the ban.

“No Ban, No Wall Protest at PHL Airport” by Joe Piette. Image from Flickr. CC BY-NC 2.0

In January, Trump imposed the first short-term block on seven Muslim-majority countries, in which perspective science researchers accepted into American institutions before January could not obtain a visa. Some of them lost the science education and research opportunities they had earned and been guaranteed. Samira Samimi, a glaciologist from Iran, had a plan of going to Greenland from New York to study snowmelt. After the ban became effective, she could no longer meet with her US team and fly to Greenland. Samimi faced potential consequences of ceasing her research project and delaying her PhD degree.

“None of this is right. There is no way this helps us or our science.” says Mike MacFerrin, a glaciologist colleague of Samimi’s.

A similar tragedy happened to Hani Goodarzi, a cancer biologist at the University of California, San Francisco. He was forced to cancel a talk at the University of Calgary in Canada, because as an Iranian migrant, he was under the fear of not being able to return to the US after leaving the country.

It is not fair for scientists to take the consequence of politics, and it is worse that life-save science researches also suffer from politics.

International projects on combatting disease were heavily interrupted. Farrokh Modabber, an infectious-disease scientist in Iran, could not attend a conference held at the US due to immigration policies. Without updated knowledge from the frontline scientists in regions emerging diseases, the development of vaccinations in the US can be slowed down significantly. As far as Nature has reported, several researches including one on HIV were all greatly hindered by the ban.

“The only way to prevent emerging diseases from coming to the US is to stop them in their tracks in the countries where they arise.” Says Peter Hotez, a disease expert at Baylor College of Medicine in Houston, Texas.

It is time to be alert that science deserves to develop without being disturbed, and politics can heavily impact science. A feasible approach to save science from bans is to exclude restrictions on highly professional individuals from policies. In fact, scientists including Nobel prize winners have already started fighting back since January, yet a lot more attention and voices are still needed for the sake of science.

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Youtube: March for Science

-Zhou Wang

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Designing new organelles

Posted on September 26, 2017 by | 1 comment

Many people may have heard about cutting and pasting genes from a genome, the complete blueprint of an organism, into microorganisms to make them magically produce compounds that they could never produce naturally. However, few experiments have endeavored to make a novel organelle, an artificial factory within a living cell. Genetic evidence shows that the mitochondrion, the cell’s power plant, was actually a bacterium that got swallowed by an ancestral cell, and it revolutionized how life works. Wouldn’t it be extremely cool if scientists could do something like that and change how cells behave?

 

Organelles are compartments performing specific functions, found within the cells of many organisms. They concentrate reactants for chemical reactions while not disturbing the cell’s other activities. For example, the organelle called peroxisome is a processing plant and protector of plant and animal cells. It degrades very long chain fatty acids from dietary fats and produces toxic hydrogen peroxide, which is safely reduced to water within. Zellweger syndrome is due to dysfunctional peroxisomes, where a person accumulates of toxic metabolites and cannot make myelin for nerve cells and bile for fat digestion, which may be fatal with no available treatment. Therefore, it is important to maintain healthy peroxisomes and their protein machineries.

Structure of Peroxisome in fixed cells, labelled with SelectFX® Alexa Fluor® 488 Peroxisome Labeling Kit. Adapted from Thermo Fisher Scientific: Peroxisome Structure

Interestingly, peroxisome proteins are imported directly from the cytosol, the fluid-filled space surrounding organelles within the cell, without going through a central protein-sorting system in another organelle, the web-like endoplasmic reticulum.

In September 2017, chemical biologist Stuart Warriner and his team at the University of Leeds, England, published their work on tweaking the natural peroxisomal protein import system by modifying two proteins involved in the pathway. They found that their new pathway overrides the natural protein carrying pathway with no adverse side effects for the cell. Theoretically, scientists could design it in whichever way they want through this simple, subtle change.

Figure 1. Scheme of research. Adapted from Figure 1 of “Towards designer organelles by subverting the peroxisomal import pathway” by Warriner et. al, 2017.

A big family of proteins called PEX (peroxins) serve as porters and receptors that recognize and dock cytosolic proteins with the five-letter amino acid peroxisomal targeting sequence (PTS; like a password) to import them into peroxisomes. However, the researchers only changed the PTS and a protein called PEX5, which wanders in the cytosol looking for homeless, PTS-carrying proteins.

 

Using known crystal structures of PEX5 protein, the researchers generated several versions of PEX5 by mutating (changing) one or two amino acids at one end that binds the original PTS. They modified the PTS by changing its last two amino acids, and identified a new PTS that rcognized the new PEX5’ but not the original.

Adapted from Figure 3 of “Towards designer organelles by subverting the peroxisomal import pathway” by Warriner et al., 2017, showing how the new PEX5 protein selectively imports new PTS-containing proteins into peroxisomes.

Unexpectedly, viewing cells with fluorescence microscope showed the natural PTS was imported by the new porter protein PEX5’, meaning PEX5’ is more lenient on PTS. However, when fluorescent PTS and PTS’ were inserted in PEX5′-containing cells, only the new PTS’ ended up in peroxisomes, leaving the PTS in the cytosol. Evidently, the new and original PTS compete for import, with the original PTS outcompeted – how they interact with other PEX proteins and by what mechanism are still mysteries. However, this means scientists can manipulate peroxisomes by simply switching to the new PEX5′ protein.

 

Custom organelles has many potential applications, such as more efficient and sustainable production of therapeutics and other synthetic compounds without compromising the cell’s other activities and health. Scientists could also design a novel waste management system for the cell by designing PTS-containing proteins that scavenges certain chemical wastes from the cytosol and import them for processing in peroxisomes. Without knowing when that day will come, meanwhile, we should appreciate what our wonderful organelles do to keep us alive!

Written by Jenny Zhong

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