A repair system in our cells fixes DNA damage caused by exposure to ultraviolet (UV) light from the sun, however the detailed process behind this is not fully understood. An international research team has clarified the regulatory mechanism of the ubiquitin-proteasome system in recognizing and repairing UV-damaged DNA.
UVA (and also UVB) radiation cause indirect damage to DNA via absorption of photons by non-DNA chromophores. This generates reactive oxygen species like singlet oxygen or hydrogen peroxide that oxidize the DNA bases causing mutations.
Most damage to DNA is repaired by removal of the damaged bases followed by resynthesis of the excised region. Some lesions in DNA, however, can be repaired by direct reversal of the damage, which may be a more efficient way of dealing with specific types of DNA damage that occur frequently.
“Sunburns are from ultraviolet radiation – or UV rays – causing damage to the skin,” George says. When ultraviolet radiation from the sun reaches the skin, it damages the skin cells and causes mutations in their DNA.
Ultraviolet light from the Sun can cause DNA damage by fusing together two of the nucleotide bases that sit side by side on a DNA strand. This forms a bulky lesion that distorts the DNA helix, making it impossible for most of the enzymes involved in DNA replication to read past the altered site correctly.
One way ultraviolet light can harm cells is by directly damaging DNA. This is something many of us are reminded of every spring and summer - it's the cause of sunburn! As the name suggests, direct DNA damage occurs when a photon of UV light hits DNA.
Most skin cancers are caused by DNA damage from ultraviolet radiation in sunlight. This study shows that a very high sun protection factor sunscreen can inhibit DNA damage in the skin caused by high doses of artificial sunlight, even when the sunscreen is used less than optimally.
"A tan is a response to DNA damage," says Dr. Barbara Gilchrest, a dermatologist at Harvard-affiliated Massachusetts General Hospital. Such damage is instrumental in the development of skin cancer, and it also accelerates skin aging.
People concocted pastes and potions to keep their skin fair. One of their go-to ingredients, rice bran, absorbs ultraviolet rays so well that it's still used in some sunscreen formulations today.
The Earth is about 93 million miles away from the sun. So your DNA could stretch to the sun and back 61 times. That is one person's DNA.
Exercise on the reg. Regular physical exercise increases antioxidant capacity, protects DNA and reduces the effects of age-related declines in DNA repair. In one study, 16 weeks of physical exercise dramatically increased antioxidant activity, decreased DNA strand breaks and promoted DNA repair.
UV Damage, Nucleotide Excision Repair, and Photoreactivation
As previously mentioned, one important DNA damage response (DDR) is triggered by exposure to UV light. Of the three categories of solar UV radiation, only UV-A and UV-B are able to penetrate Earth's atmosphere.
Summary: A major active ingredient in many sunscreens damages DNA when exposed to sunlight in a test tube, according to scientists in Northern Ireland. They say that if similar damage occurs within skin cells, it could destroy them or possibly initiate changes leading to skin cancer.
Indians enjoy the benefit of living in the tropics and our darker skin tone shields us from UV light. Our skin colour depends on a natural pigment called melanin—also known as the umbrella of the skin that protects us from UV damage.
Most people used scarves or clothing items to avoid direct sun exposure. Rice, crushed jasmine petals, olive oil, sunflower oil, lupine, pine needles, mud, charcoal, cocoa butter, and burnt almond paste were some of the everyday things that were tried before sunscreen became commercially available.
A Centers for Disease Control and Prevention (CDC) study found black people were the least likely to get sunburned. White people, on the other hand, had the highest rates of sunburn.
A small amount of sun exposure is healthy and pleasurable. But too much can be dangerous. Measures should be taken to prevent overexposure to sunlight. These preventive measures can reduce the risks of cancers, premature aging of the skin, the development of cataracts, and other harmful effects.
You can try to build up your skin's resistance to sunlight by going outside for short periods, and gradually building up the time you spend outdoors. Start with a few minutes of sun exposure early in the morning, but be careful not to overdo it otherwise you may trigger your symptoms or develop a sunburn reaction.
Several health benefit claims such as improved appearance, enhanced mood, and increased vitamin D levels have been attributed to tanning. Furthermore, the Indoor Tanning Association claims that “catching some rays may lengthen your life” [5]. Exposure to sunlight has been linked to improved energy and elevated mood.
Endogenous sources of DNA damage include hydrolysis, oxidation, alkylation, and mismatch of DNA bases; sources for exogenous DNA damage include ionizing radiation (IR), ultraviolet (UV) radiation, and various chemicals agents.
Ectoine protects DNA from damage by ionizing radiation.
Radiation damages the genetic material (DNA) causing single strand breaks (SSB) or double strand breaks (DSB) in the cells, thus blocking their ability to divide and proliferate further.
UV light is absorbed by the DNA causing several types of damage that can interfere with transcription and replication. In bacteria a number of different repair mechanisms have evolved to repair these UV-induced lesions.
Nucleotide Excision Repair (NER) Nucleotide excision repair (NER) is the main UV-damage removal pathway both in prokaryotes and eukaryotes. Humans possess only NER mechanism for the repair of dipyrimidine DNA lesions.