Category Archives: Biological Sciences

Could the new Cyclosporin be in our own bodies?

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The Immune system Simplified (Nobel Media)

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Recent research at the BC children’s hospital in Vancouver, Canada has unearthed one of the mysteries of an immune cell that may play a key role in combating auto-immune diseases.

"A Regulatory T Cell" Image Source: http://www.iayork.com/Images/2008/12-8-08/BioLegendTReg.png

The cell in question is the regulatory T cell (Treg), a regulatory cell responsible for the management of immune responses. While largely unstudied, this cell has been found to prevent disease and illness brought on by the body’s own immune system. Tregs monitor our immune systems and counter-balance the constant assault against the cells within our bodies both malignant and benign. In a sense, they’re the whistle blowers of the body police.

While the job of Tregs is to control and reduce immune response, they can also be used to quell a person’s runaway immune system and subdue the illnesses our immune systems can sometimes create.

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While Treg therapy may seem futuristically out of reach or too good to be true, preliminary trials so far demonstrated promising results in human and mouse models. Anti-immune therapies using Tregs have been so effective and versatile that they not only treat the inflammation in Crohn’s Disease but tissue rejection in organ transplants. At times, this cell is  even capable of giving the body life long tolerance to the transplanted foreign organs.

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"Simplified Illustration of the Inflammatory Response" Image Source: http://www.rkm.com.au/immunology/immune-images/IMMUNE-inflammation-R-600.jpg

Despite these triumphs, Treg therapies still have a long way to go. The recent discovery found by the BC researchers shed light on interactions of Tregs with Neutrophils, immune cells involved in the generic first response of immune systems. While Tregs are meant to suppress immune responses, they seem to attract neutrophils in vast quantities which are highly inflammatory in nature. Until more is known about the relationships and functions of Tregs, researchers may run the risk of accidentally triggering an immune response when trying to reduce it. Another possible risk to consider is that Treg therapy may increase our risk of cancer by suppressing the cells responsible for keeping it in check.

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Despite these risks it is obvious that Treg therapies have an untapped potential with almost limitless application to illnesses associated with an overactive immune system. Our bodies’ tolerance of Tregs and their adaptive and responsive nature make them not only ideal in that they act like living cyclosporine, but they have been tweaked and perfected to be the ideal  immune suppressant for over millennia, before we ever got sick.

 

 

 

Cutting out the middleman

Fungal infection of the bone marrow. Image by euthman.

Nowadays, clinical transplantation is known to save many lives, but not without a catch. Patients have to go through immunosuppressive therapy if the MHC molecules on the graft, or transplanted tissue, do not match their own.

Our bodies are very picky and sensitive. For instance, we are okay with accepting skin grafts from ourselves – this is a type of autograft. However, if we were to be given a skin graft from someone unrelated, this arrangement is not long-lived. We let this allograft stick around for a bit, but ultimately kick it out after 10-13 days. We’ll remember it, too. Like a woman scorned, if this same offensive graft comes again, we boot it out even faster. The T cells living in our bodies as defenders do not take kindly to foreign tissue. Immune responses are mounted as a result, causing transplant rejection. Learn more about the immune response here:

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For clinical transplantation to be successful, people have relied on immunosuppressive drugs to inhibit the defensive mechanisms our cells carry out when we encounter foreign molecules. This is problematic because now people are more susceptible to cancer and infections. The issue with transplant rejection is that donor and recipient cells don’t like each other. What do we do when two people don’t get along? We force them to.

Scientists have recently tested a method for transplant recipients to accept mismatched donor organs. In this ongoing trial, patients are exposed to chemotherapy and radiation and injected with enriched donor stem cells, hoping to achieve what is called “chimeric tolerance”. The idea is to make two immune systems work in one body by destroying the host’s first.

This new approach is pretty questionable. Small sample size aside, it is not known whether the enriched cells really made an impact as the study is missing a control group (where patients would presumably undergo treatment without these cells). Furthermore, these cells were not described very clearly. Suppressing the immune system with chemotherapy and radiation is also unnecessarily harmful and risky. Will it be worth it in the end?

The lengths we will go to in order to cure disease (Image from xkcd.com - click to enlarge).

References:

1. Murphy, Kenneth P. Janeway’s Immunology (8th ed), p652-664.
2. Steenhuysen, Julie. Immune system tricked to accept donor organs: study. NewsDaily. Accessed March 14, 2012.
3. Garland Science. The Immune Response. Youtube video, accessed March 14, 2012.

Kill The Winner

What We Don’t See At Sea

When we are taught about the ocean’s food chain in elementary school, it seems simple enough. The tiny plankton at the bottom are the primary producers, equivalent to the plants on land, and everything gets bigger and more interesting from there.

The layman's ocean food chain

Figure 1. The Layman's Ocean Food Chain

In fact, plankton themselves hold an enormous amount of diversity. The term “plankton” include not just plants, but every kingdom of life. Huge diversity exists within each kingdom as well, multiple species fill each ecological niche in each environment (1).

Now, that level of diversity may seem odd. For one ecological niche in one environment, shouldn’t one species come to dominate? One would think that one species would prove best able to grow in the environment, take up the most nutrients and crowd out its competitors. Yet this diversity still exists.

For oceanic bacteria at least, the reason seems to be that they are trapped in a bitter conflict, a race between their own rate of replication and how quickly their tormentors destroy them. It is a war between bacteria and viruses, one which kills as many as 50% of the ocean’s bacteria every day (2).

Killing The Winner

The Blue Shell (Nintendo Corp.)

How does this explain the level of bacterial diversity? Bacteria must find a balance between their own success and avoiding eradication by viruses. Traditionally, an organism is considered  most successful when it grows to reach the highest population that its environment can support.

Viruses usually prey on only one species. A bacterium that has achieved complete success has made itself completely vulnerable to its viruses. In a dense population of its target species, a virus will spread like wildfire, and is much more likely to completely eliminate its prey (1). This concept is called “kill the winner.”

With population density limited in this way, there is room for other species to move into the same niche in the same environment, although it may not be as well suited as its competitor. So long as no one species reaches a density that allows a runaway viral infection, it will survive.

The ecological niche still supports a maximum number of organisms, but viruses kill the winner, ensuring a diversity of species in the same niche.

To help to illustrate the relationship between rates of infection and population density, adjust the population of this zombie apocalypse model using the + and – keys. Note that when the population is dense, the infection spreads much more quickly. If the humans start off winning, they lose very quickly.

Unlike the survivors in this simulation, bacteria can replace themselves, allowing a sustained population. Between rates of replication and death by infection, each bacterial species must find a way to succeed as best as it is able.

References

(1) Fuhrman, J. A.; Schwalbach, M.: Viral Influence on Aquatic Bacterial Communities Biol. Bull. 2003204, 192.

(2) The Annenberg Foundation: The Habitable Planet. http://www.learner.org/courses/envsci/index.html (accessed 03/12, 2012).

How Forgetting Might Become the Norm

Memory is a strange thing.

The more we learn the more we seem to forget, quite literally, and in so doing we help ourselves learn even more.

A strange proposal then would be whether it possible to forget the baggage we don’t like, keep those we do, and maybe throw in some fun stuff that never happened. It all sounds crazy, but this world is a crazy place.

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To start with how, let’s look at how memories are formed. In the brain, chemicals and proteins are released that help neurons pass electric potentials between themselves, and this helps the neurons make new ion channels with each other. It’s like making phone lines of memory between brain cells. The creation of these circuits is called Consolidation and until recently was thought to be concrete.

That “recently” happened when a young graduate named Karim Nader discovered that when memories are remembered or “Reconsolidated” they can be wiped out if the chemicals aren’t there to make the connection.

It turns out that when you remember something, a few things happen. Similar memories that would compete with that memory can be mixed in or weakened/eliminated by the prefrontal cortex and the memory itself is literally rebuilt.

"Seems Like a Good Idea" Image:Eternal Sunshine of the Spotless Mind

Because of this, every time you remember something it gets a little altered in the process, and if the chemicals are blocked, the reconsolidating memory becomes wiped.

“This is crazy and awesome, but too crazy for me, can I make bad, painful memories better without this?” Yes you can. Because memories are associated with different emotions or perceptions, they’re located in different places. Negative ones are found in the amygdala, though they can be removed and relocated elsewhere. How? Think about the memory in a happier setting when you’re immune to feeling blue, it will remain in your mind but won’t have the same emotionally negative effects. This is why ecstasy is one of the most effective PTSD treatments ever.

"Pacman, eating pills to invoke trippy colours and devour your ghosts" Image:Pacman

“How can I make this more fun?” PLAY TETRIS. Playing Tetris within 4-6 hours of trauma significantly reduces the associated trauma with a painful memory. Yes folks, drugs and videogames are the answer, Pacman had it right.

“This is cool, can I be programmed with happy thoughts?” Yes you can. It turns out we’re really good at remembering things that never happened. Dr. Elizabeth Loftus has demonstrated that 1/3 of subjects can be tricked into thinking false memories are their own, even with only one exposure to it. This is why people can be convinced they met Bugs bunny at Disneyland.

“Nice, can I have this memory wipe as a pill please?” Not yet, but a scientist named Dr.Sacktor has found the primary and defining chemical involved in (re)consolidation. It’s called PKMzeta, a form of protein Kinase C. It’s needed to maintain memories, and inhibiting it while remembering something leads to a swift and selective wipe of that something.

“Do you think I can get a prescription?” You may in the future if you have chronic neuropathic pain. It likely will have the same effect on the spine as the brain, and it might even help people with addictions.

All in all this is fabulous news. Though it can be a lot to take in, whether it makes you fear an Orwellian mind control police or you’re just excited to become a mind-tweaking psychonaut, it likely won’t matter as you’ll probably forget you thought about it anyway.

"A Sea of Potential" Image from: http://thetechnologicalcitizen.com/?p=2471

Fermentation, giving variety to our diet

Fermentation is a type of biotechnology, where development of microscopic organisms promotes food preservation by generating preservative substances such as alcohol, acid and antimicrobial matters. Although fermentation is defined by the process of disintegration of carbohydrates in anaerobic environment, the term also suggests breakdown of carbohydrates as well as carbohydrate-like components in both anaerobic and aerobic conditions. Many examples of fermentation can be found in our daily lives, including drinks such as wine and sake, dairy products such as yogurt and cheese, meat products such as salami, bologna and prosciutto and other foods such as sauerkraut, soy sauce and miso. Although breakdown of carbohydrate is the main reason for the changes apparent in fermented foods, there are also other various reasons as well, such as modification made to proteins and lipids via microorganisms, which alter the physical and chemical parts of food. However, fermentation is different from genetic engineering, in which gene is modified to create better organism.

Picture of yogurt. Photo by Richard Scherzinger.

The principle of fermentation lies in the different types of microorganisms. The development of alcohol and acid-producing microorganisms suppresses decaying process by restraining the metabolism of proteoylytic and lipolytic microorganisms that spoil products. Alcohol and acid produced from fermentation are called antimicrobial agents. They are of many by-products of cultivating microorganisms in various kinds of food. Different types of alcohol and acid can form according to the food they grow upon. Some specific microorganisms contain lactic acid bacteria, acetic acid bacteria, yeast, and mold. Different microbial change occurs for each type, producing distinct products. For instance, lactic acid bacteria produce lactic acid from lactose and glucose, and generate fermented food like yogurt. They especially help in suppressing spoilage-causing and disease-causing microorganisms.

Lactic acid fermentation. Photo credited to McGraw-Hill Companies Incorporation.

One of the reasons for consuming fermented food is due to the higher nutritional value in many of the fermented food compared to the unfermented source of food. For instance, mold fermented food, such as miso, carries higher level of B-vitamin than the material to start with. Secondly, fermented food enhances our uptake of minerals and vitamins as microorganism frees indigestible nutrients of plants for humans to digest. Moreover, microbial hydrolysis of indigestible cellulosic components happens during fermentation, leaving fermented food more digestible. Not only fermented food is beneficial towards nutritional value, it also brings variety to our food choices. For example, kimchi is a famous Korean traditional fermented food that most of Koreans enjoy in their daily meals.

Picture of kimchi by Mat-jjang, a Korean blogger.

 

Here is a youtube video of the process of making kimchi if anyone is interested.

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Sources

What is fermentation http://www.wisegeek.com/what-is-fermentation.htm

Yogurt http://www.foodsci.uoguelph.ca/dairyedu/yogurt.html

Fermentation as a method of food processing http://www.eden-foundation.org/project/articles_fermentation_thesis.pdf

Yeast fermentation and the making of beer and wine http://www.nature.com/scitable/topicpage/yeast-fermentation-and-the-making-of-beer-14372813

Who is Our Ancestor?

This is Our Ancestor. Image by Prave.

Scientist belive they have found our oldest ancestor, the creature, Otavia antiqua, was found in 760-million-year-old rock in Nambia. This multicellular being spawned every living organism in this world through billions of mutation, from fish to amphibians to reptiles to birds to animals to you.

 
Otavia was a very small sponge “about the size of a grain” according to Anthony Prave, a geologist at the University of St. Andrews in the U.K. According to Prave, “certain samples would “yie thousands of specimens. Thus, it is possible that the organisms were very abundant.”
 
Based on where the fossils were discovered, Prave and his colleagues claims that it used to live in calm, nice, shallow waters, munching on algae and bacteria through pores and into its small tube body.
A scanning electron microscope view of Otavia antiqua.
A scanning electron microscope view of Otavia antiqua. Image by Prave.

 Our Ancestor is also very reslient. According to the South African Journal of Science, it survived atleast two “snowball Earth”  events, when the entire planet was almsot entirely covered with ice.

Despite the wild enviornmental swings, this creature remained almost unchanged, resisiting along with algae and bacteria for “roughly 200 million years of existence.” Prave suggested.

Paleontologist Dr. Bob Brain – who is an expert in predation- belives that Otavia was the Earth’s first predator. During the early days, it was at the top of the food chain, consuming its food while it had no means to hunt. According to Brain, this was the first evolutionary arms race, which “led to humans dominating the planet.”

References

  1. Oldest Animal – Earliest Ancestor of Us All? http://news.nationalgeographic.com/news/2012/120207-oldest-animals-sponges-earliest-science-evolution/ (accessed 02/12, 2012).
  2. Sponge-like creaure may be oldest animal ever found. http://www.iol.co.za/the-star/sponge-like-creature-may-be-oldest-animal-ever-found-1.1227656  (accessed 02/12, 2012).
  3. The oldest animal fossils. http://www.sajs.co.za/index.php/SAJS/article/view/1064/1048 (accessed 02/12, 2012).
 

A Lovely Indecision

There’s hardly anything as conflicting as tastes, especially subconscious tastes that vary on a monthly cycle and alternate with circumstance. In honour of Valentine’s Day, we shall explore the theme of indecision in female mate selection, featuring the wonders of the pill.

To begin, attraction in females shifts between when she’s ovulating and not.

While in the fertile throws of follicle phase, females generally prefer a male with manly features and high testosterone levels, as well as a dissimilar Major Histocompatibility Complex (MHC). MHCs are linked to immunity, so humans naturally seek to diversify for maximum heterozygosity and variation. A fun fact, while fertile, girls in relationships are also known to develop a taste for dominant smelling men.

YouTube Preview Image (A little More on MHC)

Most of the time though, women are not in fertile mode, and in these circumstances tend to fall back on men who have a similar MHC to themselves. They also favour men who are less masculine and more nurturing and supportive, especially if they live in a healthy environment.

Based on these natural cycles, we can see how there might be some conflict of interest depending on what day it is.

"I don't know what I want!" Image:ehow.com

Sometimes, one doesn’t even need cycles to complicate things. While single, girls have an increased preference for MHC similar men, but then have dissimilar MHC preference when they’re already with someone. If that’s not enough, these changing preferences of MHC make a huge impact as scent is much more emphasized in importance with women rather than men. Occasionally, scent can even be at odds in importance with visuals though it varies on the population and culture.

That said, a person’s heterozygosity of their MHC can be sensed through the inspection of facial features. While females favour as much heterozygosity as possible, they seem to be attracted to those with similar MHC as well.

So, visuals conflict with olfactory cues? Awesome.

Now what about the pill? Surely this fabulous contraption of contraception must simplify things no? Well, sort of.

The Pill adds some consistency, whereby everyday is non-fertile day. It’s more or less a fake pregnancy that replaces the possibility of a real one, and this causes women to go into “find a nurturing, similar man phase.” It’s without any surprise then that women on the pill have a marked preference for MHC similar men that totally overrides any ambition for seeking a dissimilar partner.

Consistency? Fabulous! What’s the catch?

Women who find their man on the pill tend to have less sexual attraction to their partners as well as decreasing sexual satisfaction over time. They become very jealous at a rate proportional to estradiol intake, and also have an increased desire to cheat, meanwhile having much more severe “affective responses” to partner infidelity, and having an increased frequency of “mate retention behaviour.” And you put on a few :3

But don’t worry, there are some positives. Those that meet their partner on the pill have more satisfaction with their partner in non-sexual ways, have happier relationships with more emotional satisfaction, and have relationships that last 2 years longer on average.

So really no matter what, it’s a mess of matter of preference. Just have a preference for the mess that you prefer.

"Use Both Instead!" Image:ehow.com

Black Stripes White Body or White Stripes Black Body

Zebras are the cute animals living on grasslands. Have you been wondering if they have black stripes with white body or white striples with black body? And, what are the stripes for anyway?

Revealing the mystery, zebras have black body and white stripes. According to Wendy Zukerman, the zebras are completely black in their early embryo stages, while the white stripes appear later on.

Also, Lisa Smith has reported that the black color is the pigment activation and the white color is the inhibition, meaning that the color of fur is orginally black while the white fur simply lacks the pigment.

Although scientists are not sure why zebras have the alternating stripes, there are some theories

Having a higher albedo, the alternating pattern of fur can deflect up to seventy percent of heat during daytime. Since a lot of zebras live in high temperature enviroment, the fur can reduce a lot of heat from the sun.

Moreover, one theory says that the alternating pattern can act as a camouflage to confuse the predators. The Stripes can form some kind of illusions to intimidate the predators like lions or hyenas. The illusion is especially effective when the zebras are in a great number, so the pattern may make them look like a giant creasure.

While there is little evidence for camouflage, a new finding Justin Marshall points out is that the pattern can get rid of horseflies becasue it “provides an unattractive surfaces” for horseflies to land on. In africa, there are a lot of horseflies, so a pattern that prevents horseflies would result in less disease and healthier zebras.

A short video about horsefly theroy.

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So the black zebras with white furs stills have their alternating pattern remained mystery. More studies are need to to support the theories such as camouflage and horsefly.

 Source

Buzzle.com.

How Stuff Works.

New Scientists.