AP Biology class blog for discussing current research in Biology

Author: ayl103


Photo Credit: mont3rros4

We all know that sleep deprivation causes the brain to become exhausted, but  a recent new study has shown that sleep deprivation causes nerve cells to become increasingly jumpy.


Most of us these days don’t get enough sleep. But sleep deprivation can cause people to have seizures and hallucinations. People believe that sleep deprivation lowers a person’s alertness, but Marcello Massimini from the University of Milan and his fellow colleagues have discovered that the brain actually becomes more reactive as hours awake accumulate.

Six people were gathered and did not sleep for a whole day. Massimini gave each person a jolt of magnetic current to the participants skull. The nerve cell received an electrical response and Massimini was able to measure the strength of the electrical response. He did this to the patients twice. Once right after they woke up from sleep and once after they hadn’t sleep for a whole day. The results were that the patients had a stronger electrical response after they hadn’t slept for a whole day than when they just woke up.

The theory is that the brain accumulates connection as the person learns new things. Sleep clears the brain of extra information and leaves only the most important information and connections. These enhanced excitability could be the explanation of why people have seizures after they haven’t slept in a whole day. Also doctors have induced seizures on patients by keeping them up all night. New studies are being tested if wether sleep deprivation can lead to reversing depression since the brain has a heightened excitement without sleep.

Other effects of sleep deprivation are stress, memory impairment, and poor quality of life. It is advisable for teenagers and adults to get about 8-9 hours of sleep. Now lets get some sleep!


Photo Credit: Ashabot

Many people say animal testing is definitely reasonable because apparently the life of a human outweighs the life of an animal. Yes, we have made much progress in finding new cures that work on being tested, but over 100,000 people die from newly prescribed medicine that cured the disease in animals. Animals have different genetic codes than humans and therefore just because the cure of a disease works on an animal does not mean that it will 100% work on humans.

Animals are being tortured during testing. They are being forced fed chemicals and are left in pain while they are locked away and are restrained. Over half of the millions animals being tested either die during the testing or are killed after tests. The Animal Welfare Act is suppose to make sure scientists treat animals being tested with good care. They must provide adequate housing, sanitation, treatment, nutrition, and veterinary care. But the Animal Welfare Act only protects animals before and after testing. So scientists don’t have to follow it during testing!

So why test on animals if its the new cures that work on animals don’t work on humans? Why put the animals through pain and suffering if the cures might not always work? I still believe that it is important for scientists to keep on developing new cures, but there are other alternatives to finding these cures other than animal testing such as using human skin cells or human skin  leftover from surgical procedures. These are ways that can still develop new cures and there is probably other methods to use to test scientists new theories and cures. So do you support animal testing?

Caffeine- helpful or harmful?

CC licensed photo by Manny Hernandez

As we all know, the highly addictive drug, caffeine, found in our coffee, tea, soda, etc… simulates us. Many people use caffeine to stay a wake which works really well. But it also causes a build up of fatty acid in the blood, raises blood pressure,  stimulates the heart, respiratory system, and central nervous system, causes stomach to produce more acid, harder to digest food because muscles surrounding the intestinal system relax, increased urination, and many other symptoms.

Is caffeine more helpful or more harmful? And where does caffeine really affect our body?

Recently, scientist have been testing caffeine on lab rats to figure out which part of the brain caffeine stimulates the most. In the first trial, they gave the rats more caffeine than what a human would normally ingest. They then decided to use  smaller amounts of caffeine which affected the hippocampus. The hippocampus is part of the brain which allows for long term memory and spacial navigation. In humans, the hippocampus is located inside the medial temporal lobe. Damage to the hippocampus may cause oxygen starvation and/or amnesia. The rats received caffeine equivalent to two human cups of coffee which is two milligrams per kilogram of body weight. The scientists measured the nerve cell’s electrical messages but examining different parts of brain tissue.

The region that had the most response to the caffeine was called CA2. CA2 showed a burst of electrical energy, while other brain regions in the hippocampus showed no sign of stimulation. The then tested the rats giving a greater dosage which caused an even greater stimulation to CA2. After that the scientists directly injected caffeine into nerve cells in a dish and the results were the same as before. About 5 minutes of caffeine intake allowed for the synapses to stay amped for three hours.

The scientists believe that when humans use caffeine the same area, CA2, will be stimulated and may strengthen a persons ability to learn and memorize, but this is just a hypothesis since they only tested on rats. So you decide… is it helpful or harmful?

Cantaloupe- the Killer Fruit?

Photo Credit: Cantaloupe by Kabsik Park

On September 30, 2011, cantaloupe has killed fourteen people and sickened seventy-six people in eighteen states.  The cause of this is listeria in Cantaloupe.

Listeria is the deadly bacteria, which can replicate inside a human cell once it penetrates the cell.  Listeria symptoms are usually unnoticeable and they only last a week and then it is spontaneously resolved. If listeria replicates and spreads to the brain, it can cause meningitis, alter mental condition, cause seizures, and death.

In Colorado, the FDA and state health authorities are working together to figure out how the cantaloupes were contaminated. They are wondering whether or not the cantaloupe had been infected with the bacteria through contaminated irrigation waters. There has been a drought in Colorado, therefore the farmers have been accessing water from all sorts of places such as animal vectors.

Cantaloupes are one of the only fruit than can cause an outbreak. Melon’s rough skin allows it to trap bacteria. The exterior of the cantaloupe provides a great site for the bacterias to attach. Once attached it can multiply and then penetrate the skin leaving someone with an infected cantaloupe.  Cantaloupes can be contaminated with the bacteria anytime during its contact with the ground, but the most likely time of contamination is during its harvesting. Animals are attracted to the ripe melons and can spread bacteria through the irrigation water.

Deaths are still accumulating and as of Wednesday, October 12 there have been 23 deaths and 116 sicknesses. Countless cantaloupe farmers have lost their jobs because of the cantaloupe retraction. Will you chance your life by eating a cantaloupe? Seriously don’t eat them…it can kill you.


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