AP Biology class blog for discussing current research in Biology

Author: saysquad

Save the Devils

When most people hear the name Tasmanian Devil, they think of the small and ferocious little animal from the Looney Tunes named Taz. Just like in the show, Tasmanian Devils (carniverous marsupials)  are tough, rugged and very aggressive animals. Unfortunately, over the past two decades, a rare case of contagious facial cancer, with a 100% mortality rate, has decimated the population. Scientists have estimated that this specific cancer has wiped out about 85% of the entire population, almost to the point of extinction. The cancer is typically spread when the Devils bite each other in the face during battle, killing it in a matter of months. Scientists are working tirelessly to find out how this cancer is slipping by the immune system and hope to find a cure.

Until recently, scientists believed that the cancer was able to develop, without

being detected by the immune system, because Tasmanian Devils lack genetic diversity. However, a study led by the University of Cambridge claims it is much more complex. On the surface of most cells are histocompatability complex (MCH) molecules, which determine whether other cells are good or bad. If the cell happens to be a threat, then the cell triggers an immune response. According to the research, these DFTD cancer cells lack theses complexes and can therefor avoid detection.

Researchers also found that the DFTD cells have just lost the expression of MCH molecules and that its genetic code is still in tact (it can be turned on). By introducing specific signaling molecules, scientists believe they can force the DFTD cells to express these molecules, leading to the detection of the cancer. Not only will this research help save the Devils, but it will also give scientists a head start on contagious cancers in other species when the time comes.

Guts or Glory?

According to Aristotle, what separates man from beasts is his ability to reason. Humans have this luxury because of their large brains, but it comes at a price; guts! Scientists have long imagined that big brains come with an evolutionary cost and up until a recent study, it was all theory.

A Swedish team of researchers, led by Niclas Kolm decided to put this theory, known as the “expensive tissue hypothesis”, to the test. The hypothesis basically states that there is a trade-off between the demands of the brain and the demands of other organs. So, to prove this theory, the team selectively bred common guppies to produce bigger (or smaller) brains. They were able to produce brains that were as much as 9.3 percent larger. The bigger brained fish tended to have smaller guts, as well as produce fewer offspring.

The experiment tested 48 guppies using an underwater arithmetic test to see if the guppies (with large brains) possessed greater cerebral capabilities. It worked! The “smart” fish were more successful at learning and recognizing geometric shapes, that were on a door, in order to get to the food on the other side.

Where these “brainy” fish lost ground, was in the gut division. Males were found to have a 20 precent decrease and females an 8 percent decrease in gut size. Brainier fish(females) were found to produce 19 percent less offspring than the smaller brained fish. This evidence implies that larger brains may be the cause of smaller broods.

Even though the evidence pretty clearly supports the “expensive tissue hypothesis”, Kolm and his team have not completely ruled out the “genetic mechanism for the trade-off”. It is not obvious whether small guts or big brains develop first.

Math Sucks!

Many people, including myself, hate, or have a strong disliking for math. Math, as I see it, is the study of just a bunch of random numbers and symbols, thrown together, that mean virtually nothing. It is intangible. How much worse can it get? Often times, when I “do” math, I ask myself: how is this going to benefit me in the future? The answer is: it won’t! According to a recent study, all math has in store for me, and other math haters out there, is pain. So all of those long, seemingly endless hours of doing math, have just caused suffering. This is just wonderful.

At The University of Chicago, a team of researchers, including Ian Lyons, discovered that worrying about math can activate regions of the brain, associated with physical pain. People who experience high levels of anxiety, or anxiety at all, when expecting something math related task, sustain increased activity in regions of the brain connected with physical pain. The higher the individuals’ anxiety is, the greater the brain activity is.

The research was done on 14 individuals, who experience math anxiety, according to a survey that was completed. The questions, on the survey, asked about their feelings when encountering anything math related, and measured their anxiety based on their answers. Additional testing concluded that the individual chosen, were not generally anxious people. Their elevated levels of anxiety were a product of math.

After completing the survey, the test subjects were tested in an fMRI machine, while faced with math related tasks. Some of the tasks included: solving equations, in addition to completing word problems.The fMRI scans showed that the anxiety of anticipating math, activated a reaction, in the brain, similar to physical pain. The worse the anxiety is, the more active the brain becomes. The region of the brain that is responsible for this is the posterior insula.

The Black Mamba an Ally?

As the fangs pierce the skin, passing through the epidermis and into the dermis, you  may notice a feeble prick. Then, you will experience a numbness, similar to the one you get with pins and needles, and it will begin spread throughout your appendages. Within minutes your central nervous system will begin to shut down, leaving you without any hope of survival.  Within a half hour, your body will be overcome by convulsions, paralysis, and eventually you will meet your end by suffocation.

The Black Mamba, due to an assortment of different elements, including its aggressive behavior and its lethal venom, is possibly the deadliest species of snake on the planet. Untreated bites have a mortality rate of 100%. That, to me, is pretty convincing evidence.Recently, scientists have discovered “pain-relieving” compounds, known as peptides, within the venomous cocktail of the Black Mamba. The researchwas led by Sylvie Diochot, of the Institute of Molecular and Cellular Pharmacology at Nice University. She and her team, purified the peptides from the snake’s venom and profiled the compounds’ structure. These peptides are called mambalgins. The researchers were able to test the mambalgins on different strains of mice. The team of researchers concluded that the mambalgins work by blocking, or inhibiting, the ASICs, a set of neurological ion channels associated with pain signaling, in either the central or peripheral neurons. They also discovered that the mambalgins are not toxic, and can have the same, strong effect as morphine. Even better, mambalgins cause a significantly less amount of tolerance than morphine, and generate no risk of respiratory distress and other side effects that are prevalent with “pain-relieving” drugs.The discovery of these mambalgins may prove to be an enormous medical breakthrough. Due to the venom of perhaps the world’s most deadly snake, the insufferable pain of many human beings may be be abolished indefinitely.



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