AP Biology class blog for discussing current research in Biology

Tag: skin

Scraping Your Knee at 12:00am vs. Scraping Your Knee at 12:00pm: What’s the Difference?

By the time you reach the age of five, you’ve probably scraped your knee more times than you can count. Now, think back to the last time you fell off your bike or stubbed your toe during the day and the last time you did the same at night. Do you remember a difference? Chances are, you weren’t paying close enough attention, but there are scientists who were, and they have come to an interesting conclusion. According to a new study from England, nighttime injuries take longer to heal than daytime injuries, 60% longer to be exact! Why? It all has to do with the biological clock and the 24-hour cycle of cardiac rhythms of skin cells.

The Healing Process

Fibroblast skin cells are found in the deepest layer of the skin called the dermis. Check out the picture on the left for a close up view! When an injury occurs, fibroblasts travel to the surface of the skin, where their job is to synthesize and build the structural support of the new skin. How fast the fibroblasts travel to the surface depends on the time of day and the biological clock. Actin, a protein that forms the supportive structure of the cytoskeleton and gives a cell its shape, is the reason behind this difference. Ned Hoyle, a molecular biology researcher, studied the changes in actin over time, and came to the following conclusion: during the daytime, actin is in the form of long filaments, while at night, actin is in globular form. Actin filaments are crucial in helping cell moves, so when actin is in globular form, it takes longer for the fibroblast cells to travel to the surface of the skin.

The Evidence

The team of researchers conducted experiments on mice, which exhibited the same affect they had studied previously – the healing time at night is longer than during the day. Next, the team turned to humans, studying burn patients. From hospital records, they concluded that on average, burns that occurred during the day healed within 17 days, whereas burns that occurred at nigh healed within 28 days. However, there are still a lot of unknowns. Scientists predicted that the fibroblasts would make up for lost ground during the day, but in reality, the cells wounded during daytime never catch up.

What’s Next?

Although we can’t plan when we get hurt, this research is extremely important. Hoyle said that this research could be expanded to trying to make cells think its daytime, if a procedure takes place at night. Furthermore, he hopes to conduct more research on the complex process of healing and blood clotting. To check out their full study, click here!

With Summer Around the Corner, Will You Keep An Eye Out to Protect Your Skin?

Piece of Human Skin

Tanning Salons are extremely dangerous to one’s health due to the unnatural and intense UVA and UVB rays that are aimed at the skin. These Ultra Violet rays can lead to premature aging of the skin and skin cancer. While most people know the dangers of tanning salons, many people are unaware of the dangers of natural sun tanning.

Natural sun tanning can be as bad as tanning salons. Your risk of skin cancer increases as you spend more time underneath the strong sun. “According to Arthur Sober, M.D., associate professor of dermatology at Harvard University Medical School, ‘On a cloudy day, a person feels cooler, but is still getting a good amount of UV exposure’.” (FDA, Which means that although it may be cloudy you are still coming in contact with UV rays. There is still enough sun rays penetrating the newly weakened ozone layer to have an effect on your skin!

The sun has vitamin D which is beneficial to our bodies, so about fifteen to twenty minutes of sun a day is healthy, but not more than that.

The sun emits two major wavelengths- UVA and UVB and these wavelengths increase one’s chances of skin cancer. The body tans because the body is being injured by ultra violet radiation that hits the skin. “These UV rays cause the body to produce an excess amount of melanin which acts like a natural sun screen. In order to get a tan, you must injure your skin first.” (FDA, In addition to the risk of skin cancer from sun tanning, UVB rays impair the body’s immune system, which normally defends against disease. This increases one’s chances of skin cancers and other diseases.

“UVA rays speed up the skin’s aging due to the changes in the skin’s collagen, the protein in the skin’s connective tissue.” (FDA, Many cosmetic companies make cremes enhanced with collagen for older women; they add extra collagen on their skin in hopes of reducing the amount of wrinkles they have.– These UVA rays speed up the wrinkling process of you skin, causing pre-mature aging.

Statistics about skin cancer:

“-Skin cancer is the most common form of cancer in the United States. More than 3.5 million cases in two million people are diagnosed annually.

-Melanoma accounts for about three percent of skin cancer cases, but it causes more than 75% of skin cancer deaths.

-Melanoma is the most common form of cancer for young adults 25-29 years old and the second most common form of cancer for adolescents and young adults 15-29 years old.

-A person’s risk for melanoma doubles if he or she has had five or more sunburns at any age.

-More than 20 Americans die each day from skin cancer, primarily melanoma. One person dies of melanoma almost every hour.”


Try to keep these statistics in mind and protect your skin from being harmed by excess sun!

Read more at:


Have biologists discovered the new super glue?

Have you ever seen a gecko or lizard on a vertical 90 degree surface, and wondered how they are able to stick to the wall? In fact, it is not because of any type of gluey substance or sticky secretions. According to a recent article, biologists have been able to figure out exactly how a gecko can stay on a wall without slipping. Scientists have even been able to utilize this discovery and have invented “Geckskin”, a flash card sized pad that can hold up to 700 pounds on a vertical surface.

Doctoral Alfred Crosby at UMass Amherst commented that a gecko’s feet can attach and detach from a surface with ease without any residual sticky material being left over. Properties such as high capacity, reversibility, and dry adhesion that geckos use to adhere to surfaces, allow for a wider range of ideas for synthetic materials with similar traits of gecko feet. Moreover, Crosby says that Geckskin uses many of these properties to achieve a drastic result; Geckskin can hold up to 700 pounds while only being the size of an index card. This is amazing considering the fact that this small piece of synthetic material can hold up to the equivalent of seventeen 42 inch flat screen TVs on a flat vertical surface. Although having impressive adhesive ability, Geckskin can also be used a series of times without losing its overall effectiveness and stickiness.

Geckos were once thought to get their amazing adhesive properties only from microscopic hairs only their feet called setae. However, much of the gecko’s “stickiness” comes from other complexities on the foot such as specialized bones, tendons, and skin that work along with setae in order to produce those viscous properties. Geckskin combines all of these complexities to form a synthetic tendon made out of stiff fabric and a special weave in order to maximize surface area and contact. Generally, Geckskin be made relatively cheaply and can have many different uses in the home or in the work place. What uses for Geckskin can you think of?

It Seems that Our Eyes are Quite Similar to Our Skin

Credit: Jules.K. Flickr

A breakthrough has been made in how our skin absorbs energy from the sun, as it has been discovered that ultraviolet receptors in the skin react to UV light much faster than previously believed.

UVA light, which accounts for approximately 95% of the ultraviolet radiation that reaches Earth’s surface from the sun, causes pigment producing cells in the skin to create melanin, which protects the skin by absorbing the UVA radiation.  As the melanin pigment is created, calcium is released.

What has been particularly interesting is that the discovery has found that the human skin uses a similar mechanism to that used by the retina to detect light.  It seems that the eye and the skin, the only two organs that are constantly exposed to solar radiation, use similar molecular mechanisms to decode light.  Additionally, according to Elena Oancea and colleagues at Brown University, the process occurs much quicker than what was previously known.  The discovery of the quick biological reaction that takes place in the skin in the absorption of light can have an important application, as new sunscreens can be designed that will be more effective.

“We hypothesize that the early melanin production triggered by rhodopsin activation provides a first line of defense against ultraviolet light-induced damage,” says Oancea. “If this is the case, then this pathway and its protective capacity should be taken into consideration in the design and use of broad-spectrum sunscreens.”

What do you think?  Will this discovery have an important impact, and lead to the creation of more effective sunscreens?  I hope this means that I won’t ever get another sunburn again.

For a detailed look at Oancea’s data, check out her research report,  Identification of Light Sensing Receptors from Skin    ,  and this link:


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