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Regina's Biology Blog

By Regina Bailey, About.com Guide to Biology since 1997

Natural Killer Cells

Saturday May 17, 2008
Scientists have discovered a method for increasing natural killer cells that are found in umbilical cord blood.

In studies, these cells were shown to decrease the number of human leukemia cells in mice.

One exciting aspect about natural killer cells is that they appear to only target cancerous cells while leaving healthy cells unharmed.

For additional information, see:


Know Your Heart

Friday May 16, 2008
Image courtesy of MedValet
The heart is the organ that supplies blood and oxygen to all parts of the body.

It is about the size of a clenched fist, weighs about 10.5 ounces and is shaped like a cone.

Structures of the heart include atria, ventricles, valves, arteries, and veins.

Do you know which artery carries de-oxygenated blood from the heart to the lungs? Test your knowledge of heart anatomy.

Take the Heart Anatomy Quiz!

For more biology quizzes, visit:


What are Peroxisomes?

Friday May 16, 2008
Peroxisomes are microbodies that break down fatty acids and help detoxify substances in the body.

They are found in eukaryotic cells and contain enzymes that produce hydrogen peroxide as a by-product.

Peroxisomes have the ability to assemble themselves. They reproduce by a process called peroxisomal biogenesis.

To learn more about cell structures, visit:


Steno Bacterium Sequenced

Friday May 9, 2008
Scientists from the Wellcome Trust Sanger Institute have genetically sequenced the Steno bacterium.

Steno is a quickly emerging hospital superbug that is extremely drug resistant.

There are no known drugs capable of combating these microorganisms.

Researchers hope that this genome sequence can give clues as to how Steno resists antibiotics. With that information, possible ways of combating these germs can be developed.

For additional information, see:


Hormone Increases Desire For Food

Friday May 9, 2008
Photo courtesy PDPhoto.org
Researchers have discovered that the hormone ghrelin plays an important role in overeating by stimulating the brain's pleasure center.

Ghrelin stimulates our appetite and also increases our desire for food.

Using functional magnetic resonance imaging, researchers were able to measure brain responses in people who viewed pictures of food and nonfood images.

The study showed that people who were given ghrelin had an increased response to food images in several areas of the brain.

For additional information, see:


Cancer Gene

Thursday May 8, 2008
Researchers have discovered a previously unknown cancer causing gene.

This gene, RBM3, also contains a protein with the same name. They are both important to the process of normal cell division.

In the study, researchers discovered that the RBM3 protein is present in many cancer cells. Too much of this protein causes cells to become cancerous by inhibiting cell death and allowing the cancerous cells to grow.

When levels of the RBM3 protein were reduced, the cancerous cells died.

For additional information, see:


Viruses That Infect Animal Cells

Saturday May 3, 2008
Papillomavirus
© Linda M. Stannard University of Cape Town
At one time or another, we have all most likely been infected with a virus.

For instance, colds and the chicken pox are two common ailments that are caused by viruses.

There are several types of animal viruses. They are commonly grouped into families according to the type of genetic material present in the virus.

Like all viruses, animal viruses are intracellular obligate parasites. This means that they can only reproduce after invading the host animal cell.

For additional information, see:


Fast Food and Liver Damage

Friday May 2, 2008
Studies have shown that eating too much fast food can lead to liver damage.

A diet high in fat and sugar can cause serious diseases of the liver such as cirrhosis.

However, doctors believe that liver damage due to a high fat and sugar diet can be reversed through improved eating habits and exercise.

For additional information, see:


What are Cilia and Flagella?

Friday May 2, 2008
Cilia and flagella are protrusions from some cells that aid in cellular locomotion.

If the protrusions are short and numerous they are termed cilia. If they are longer and less numerous (usually only one or two) they are termed flagella.

Both cilia and flagella are found in many types of cells. The sperm of many animals, algae, and even ferns have flagella.

Cilia can be found in areas such as the respiratory and female reproductive tracts.

For more information, see:

Dinosaurs Linked to Birds

Saturday April 26, 2008
Molecular analysis of a dinosaur protein has linked dinosaurs to modern birds.

These findings, published in the journal Science, show that dinosaurs share a common ancestor with chickens and ostriches.

Researchers were able to retrieve the dinosaur protein from the fossilized leg of a Tyrannosaurus rex.

In addition, researchers also confirmed a link between mastodons and modern elephants through collagen protein analysis.

For additional information, see:


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