Category Archives: Science Club

Tongues ‘taste’ water by sensing sour

All we know about water is that water is an odorless, tasteless, slightly compressible liquid when it’s pure. However, when we drink water, we can know that it’s water. It might be unsurprising to notice that we’re drinking something liquid. But how do we know that it’s water, not syrup? Then, does it mean that water has a taste? – actually not. According to the new study, we can recognize the water not by tasting the water itself, but by sensing acid which is produced when we drink water.

All mammals need water to sustain their life. When we drink water, we have to drink the water through our mouth.According to Yuki Oka who studies the brain at the California Institute of Technology in Pasadena, our tongue has evolved to detect some necessary materials for survival like salt and sugar. This, in other words, means that the sense of detecting water would have evolved.

It is already found that a brain area called the hypothalamus controls thirstiness of mammals. But a brain cannot decide the taste of something alone because, in order to taste something, the brain should cooperate with a mouth and receive a signal from it to know what the person’s eating or drinking. Oka says, “There has to be a sensor that senses water, so we choose the right fluid.” If we cannot distinguish the water from others, we might make a fatal decision, such as drinking poison instead of water.

To prove the water sensor, Oka and his group used mice. They dripped different flavors of liquid onto mice’s tongues. They observed a signal from the nerve cells attached to the taste buds when they were drinking, and mice showed a great nerve response to all tastes. However, the main point is that they reacted to water similarly. Somehow, the scientists discovered that taste buds are able to detect water.

Our mouth is filled with a lot of saliva— a mixture of enzymes and other molecules. Also, the mouth includes bicarbonate ions (HCO3-), which make saliva more basic. The pure water has lower pH than basic saliva. When we pour the water into the mouth, it washes out the basic saliva and enzymes in our mouth instantly starts to replace the ions. It combines carbon dioxide and water to produce bicarbonate. As a side effect, it also produces protons. The bicarbonate is basic, but the protons are acid. Then, the receptors on our tongue detect acid that we usually call ‘sour flavor’ and sends a signal to the brain.

To confirm this, Oka and his group used a technique called optogenetics. In this method, scientists insert light-sensitive molecules, which trigger an electrical impulse when shone with light, inside cells. With this principle, Oka’s team added a light-sensitive molecule to the sour-sensing taste bud cells of mice. As they shone the light to their tongues, they started to lick the light as if they lick the water. By stimulating acid sensor, they misunderstood it as water.

To the other group of mice, Oka’s team removed the sour-sensing molecule by blocking the genetic instructions that make this molecule. As a result, they weren’t able to know whether what they’re drinking is water or not. They even drank thin oil instead. Oka and his group published their results on May 29 in the journal Nature Neuroscience.

Scott Sternson, who studies brain’s mechanism for controlling animal behavior at a Howard Hughes Medical Institute research center in Ashburn, VA, says it’s crucial to learn how we sense simple but vital things, such as water. “It’s important for the basic understanding of how our bodies work,” he says.

Some people might think it’s a weird concept that the water has a sour ‘taste’. Flavor is a complex interaction between taste and smell. So, detecting water is quite different with tasting. Water may still taste like nothing, but to our tongues, it’s definitely something.

Reference: https://www.sciencenewsforstudents.org/article/tongues-taste-water-sensing-sour

 

What is “Phantom Pain?”

Phantom pain sensation refers to a person’s feeling related to limbs or organs that are physically not a part of their body. For example, let’s say that a part of a person’s body, such as an arm, was amputated because of an accident. If the person has a phantom pain sensation, then he would feel pain in the position where his arm supposed to exist, even though he doesn’t have an arm (this particular phantom pain related to the limbs are called phantom limb pain).

Then why do these kinds of phenomenon occur? According to the scientists, when a part of a body is amputated, then the region of the brain that was needed for the control of that part of the body is no longer needed, and the neuronal system in the part of the brain falls into disarray. To fill the empty spots in the brain, those parts of the brain take over the tasks of the neighboring neurons and become rearranged to do different things. However, when the brain tries to adapt to the new situation, in some cases this process goes wrong, which eventually causes the phantom pain.

As you can see, there are no apparent causes of the phantom pain discovered by scientists because there might be other reasons other than the cerebral shifts such as inherited nerve damages. However, using fMRI, a method to distinguish the active parts of the brain while it’s working, scientists have discovered that degree of the shifts related to the functions in our brain caused by amputation (and many other factors) is directly proportional to the intensity of pain the patient receives through the phantom pain. Also, researchers found out that a person with a functional artificial limb has felt less phantom limb pain than the patients that do not have it.

Even though it might take some time, a cure for phantom pain keeps on developing as the researches related to phantom pain proceed. I hope that later, the patients would not suffer from their phantom pain, or, in my own words, “false pain.”

 

References

12 July, 2017 – Episode 627 – This Week in Science Podcast (TWIS)

http://www.twis.org/broadcasts/

https://en.wikipedia.org/wiki/Phantom_pain

What is CRISPR Cas9?

Have you ever heard about hemophilia? It is a rare genetic disease that disables people from clotting blood. There is not yet therapy for hemophilia. However, a new technology to change the genes related to hemophilia was developed recently. The key point in this new technology is CRISPR-Cas9. It is genetic engineering tool which enables people to cut specific region of DNA and to insert another homologous DNA. Cas9 and guide RNA (gRNA) are important molecules in CRISPR-Cas9.

Cas9, a restriction enzyme, was first discovered in the 1980s. When a virus infects a bacteria, the bacteria cut the intruder’s DNA by using Cas9.

gRNA is made from a small piece of pre-designed RNA sequence. gRNA helps the Cas9 enzyme to cut particular regions of DNA.

CRISPR stands for Clustered Regularly Interspersed Short Palindromic Repeats. Also, Cas means “CRISPR associated.” Even though this method does not destroy surrounding genes, it is possible to change a particular DNA sequence. Treatments for hemophilia using CRISPR-Cas9 are being studied now in the USA. Researchers say, “If a ‘normal blood clotting factor’ gene is inserted into a hemophilia patient, his or her blood will be clotted.”

In addition to hemophilia, CRISPR therapy related to HIV is also being studied. HIV, or Human Immunodeficiency Virus, is a virus that infects the body immune cells and corrupts the immune system.  One typical thing of HIV is that it can go into the immune cell using the specific receptor proteins that are on the surface of the immune cells. Using CRISPR method, scientists found out that getting rid of these proteins makes HIV unable to infect another cell. Then, without the proteins that enables them to infect other cells, HIVs cannot replicate themselves and therefore collapse.

Also, CRISPR is applied to not only curing genetic diseases but also developing plants and animals. By using CRISPR, researchers made MSTN, which limits the growth of pigs, not perform its role. As a result, researchers were able to get a “super pig,” that has more muscles than normal pigs.

The usage of CRISPR can make valuable crops. In 2016, Dr. Yang and his companions made new mushrooms that doesn’t turn into brown by eliminating the enzymes that cause browning in mushrooms. Korean researchers also developed various crops, such as lettuce that has resistance in harmful insects and bean that decreases the level of cholesterol.

Although CRISPR Cas9 is touted through many positive results, it is a controversial topic. For example, CRISPR Cas9 can be used in manipulating embryonic genes, which causes the whole fetus to change. Some countries prohibit this for ethical reasons. In contrast, the Human Fertilisation and Embryology Authority authorized to alter human embryos in the UK in 2016. Even though there are lots of positive effect modifying genes, we must know that there are some ethical issues that we must concern.

References

http://www.alphr.com/bioscience/1001654/darpa-offers-50-million-to-make-crispr-gene-editing-safer
http://news.mk.co.kr/newsRead.php?year=2017&no=461478

http://science.ytn.co.kr/program/program_view.php?s_mcd=0082&s_hcd=0010&key=201706011107334239

https://www.youtube.com/watch?v=2pp17E4E-O8

http://www.yourgenome.org/facts/what-is-crispr-cas9

10% of Brain??

‘So how much percentage of brain did Einstein took advantage of?’

 

This is a question we ask ourselves after being mesmerized by the catchy internet phrase; people use only 10% of their brain.

However, this is an error made by two Harvard psychologists William James and Boris Sidis while they were studying a very high IQ child named Willian Sidis(adulthood IQ between 250-300). They claimed that people only attained a fraction of their mental potential. This statement has been misinterpreted my times resulting in the myth.

In fact, it has been proved that humans use all parts of their brains for different tasks throughout their life.

The human brain is very perplexing. Along with some mundane acts-just some millions-, brain carries out manifestos and comes up with neat solutions to equations. It also analyzes human emotions, experiences as well as the repository of memory and self-awareness.

So basically, this mistake made by some psychologists is so wrong that it is even laughable. What is correct, however, is that at certain moments in anyone’s life, such as when we are simply at rest and thinking, we may be using only 10 percent of our brains.

Although it is ironic, people can use 100% of their brain when they don’t even understand half of this soft tissue.

 

Could humans ever regenerate the heart? The answer is YES.

 

Nowadays, there are a lot of people who need the organs immediately, but there are not that many supplies of organs to fulfill their needs in order to save their life. However, recently, the scientists figured out that the answer for whether it is possible to regenerate the organs turned out to be YES. In a new study published in the journal Proceedings of the National Academy of Sciences, the University of Florida scientist and colleagues found genes known to form hearts cells in humans and other animals in the gut of a muscle-less and heartless sea anemone. However, this is not just a simple, ordinary creature. It has very unique superpower-like abilities, which is it can be cut into many pieces and each piece will regenerate into a new animal. They figured out that this is very useful because they can modify the genes in this sea anemone and cut it into tiny pieces, then it’s population will automatically increase and it would make a new animal.

But how does it work? Usually, in humans, it doesn’t work. If we take the skin off and try to regenerate into the heart, it is impossible to do it. The reason why it is impossible is that we do have ‘lock down loops’. This is the thing when the genes are turned on once, they tell each other to stay on in an animal’s cells for its entire lifetime. In other words, animals with a lock-down such as vertebrates and flies on their genes cannot grow new heart parts or use those cells for other functions. Thus our skin cell can only produce skin cell.

On the other hand, apparently, in sea anemone embryos, the lock-down loops do not exist. Which means one cell can easily change to other cells and be part of it naturally. Scientists can easily modify the genes and make it into a heart, which can save one’s lives. Moreover, according to the website, the study supports the idea that definitive muscle cells found in the majority of animals arose from a bifunctional gut tissue, that had both absorptive and contractile properties. And, in the sea anemone tissue, it has characteristics of the heart cells which is rhythmic peristaltic waves of contraction. Thus, this might be the key to produce not the artificial organs, but the real organs made from the animal.

 

References: https://www.sciencedaily.com/releases/2017/06/170626190625.htm

https://www.sciencealert.com/scientists-could-one-day-regenerate-a-human-heart-suggests-a-new-study

DEVELOPING TREATMENT FOR CANCER

Do you know what is the most probable cause of death in Korea? It is cancer. However, many types of carcinostatic agents have developed over the years. There are three kinds of the carcinostatic drugs: chemical drug, target drug, immune drug. The problem of the chemical drug is that it attacks not only cancer cells but also normal cells. It causes many side effects such as hair loss or anemia. The target drug was studied to overcome this problem. It attacks only cancer cells. The target drug can discern what is the cancer cell or the normal cell by recognizing specific genes or proteins. For instance, a gene called BRCA that causes the breast cancer can be the target. However, sometimes these specific substances live in the normal cells. It results in the side effects. To be specific, there is Herceptin which attacks HER2. The problem is that HER2 is found not only in the cancer cell but also in the normal cell. For this reason, the side effect associated with a heart can occur. Furthermore, the cancer cell can come up with a new way to survive, when the target drug is prescribed. The immune drug is differentiated from the chemical agent and the target drug in the light of the fact that it does not attack the cancer cells directly. It attacks the cancer cells by using immune cells. It is hard for the immune cells to discern the cancer cells are enemies or not because the cancer cells apply immune escape strategy. However, the immune drug attacks immune escape substances. Therefore, immune cells can recognize that the cancer cells are enemies. Immune cells begin to attack the cancer cells. It can prevent the growth of the cancer cells. The advantage of the immune drug is that there are almost no side effects. Recently, the immune drug shows good results at the treating of lung cancer.

The problem of the chemical drug is that it attacks not only cancer cells but also normal cells. It causes many side effects such as hair loss or anemia. The target drug was studied to overcome this problem. It attacks only cancer cells. The target drug can discern what is the cancer cell or the normal cell by recognizing specific genes or proteins. For instance, a gene called BRCA that causes the breast cancer can be the target. However, sometimes these specific substances live in the normal cells. It results in the side effects. To be specific, there is Herceptin which attacks HER2. The problem is that HER2 is found not only in the cancer cell but also in the normal cell. For this reason, the side effect associated with a heart can occur. Furthermore, the cancer cell can come up with a new way to survive, when the target drug is prescribed. The immune drug is differentiated from the chemical agent and the target drug in the light of the fact that it does not attack the cancer cells directly. It attacks the cancer cells by using immune cells. It is hard for the immune cells to discern the cancer cells are enemies or not because the cancer cells apply immune escape strategy. However, the immune drug attacks immune escape substances. Therefore, immune cells can recognize that the cancer cells are enemies. Immune cells begin to attack the cancer cells. It can prevent the growth of the cancer cells. The advantage of the immune drug is that there are almost no side effects. Recently, the immune drug shows good results at the treating of lung cancer.

The immune drug is differentiated from the chemical agent and the target drug in the light of the fact that it does not attack the cancer cells directly. It attacks the cancer cells by using immune cells. It is hard for the immune cells to discern the cancer cells are enemies or not because the cancer cells apply immune escape strategy. However, the immune drug attacks immune escape substances. Therefore, immune cells can recognize that the cancer cells are enemies. Immune cells begin to attack the cancer cells. It can prevent the growth of the cancer cells. The advantage of the immune drug is that there are almost no side effects. Recently, the immune drug shows good results at the treating of lung cancer.

 

Reference : http://science.ytn.co.kr/program/program_view.php?s_mcd=0082&key=201707061056052577

 

Hawaiian biodiversity is declining for millions of years

 

Hawaii’s unique animal and plant diversity has been declining on all but the Big Island for millions of years, long before humans arrived, according to a new analysis of species diversity on the islands by the University of California, Berkeley, evolutionary biologists.

The team concluded that animal diversity of Hawaii have already decreased before human’s involvement in animal extinction. The shrinking areas of old islands

Today, all of the islands except the Big Island of Hawaii — the only island still growing — have experienced a decrease in species diversity, albeit imperceptibly on human time scales, since even before the extinction caused by human activity.

They reached this conclusion with a new method for analyzing the species diversity on the different islands in the multiple-island chain, deducing the history of diversification on each island with their new approach for 14 different groups, or clades, of birds, insects, spiders, and plants.

The volcanic Hawaiian islands we see today emerged from the waves over a period of about 6 million years, carried northwestward as the ocean crust moved over from the hot spot that brought the magma from inside Earth to the sea floor to build the islands. Kauai emerged slightly more than 6 million years ago, the newest, the Big Island of Hawaii, only about 1.3 million years ago.

Each new islands, colonized by plants and animals of older islands, lead a wealth of new species that filled each island’s ecological niches. For instance,  honeycreepers, an endemic group of bird species, and the unique silverswords filled all of Kauai’s carrying capacity -the number of species a particular ecosystem can support – within about 3 million years.

Marshall realized that “the progression of islands of the Hawaiian archipelago can be viewed as an evolutionary time machine,” revealing “rates of species-richness change for endemic species of the archipelago,” which has virtually no fossil record.

“It is increasingly appreciated that the biota of any particular place is a dynamic, ever-changing association of species,” Lim said. “The beauty of islands like Hawaii is that their geologic setting provides multiple temporal snapshots, and in so doing provides us a window to understanding the processes that have shaped its assembly through time.”

 

Reference

http://news.berkeley.edu/2017/03/16/hawaiianbiodiversityhasbeendecliningformillionsofyears