UV damages

I find it interesting how difficult it seems that being able to track a connection between rates of skin cancer and the hole in the ozone layer. As the textbook noted, not only is the time delay between over-exposure to UV-B rays and the development of malignant melanoma 15-25 years but the lifestyle changes that have occurred over the past decade or so will make it incredibly difficult to know exactly how much the depletion of the ozone layer has will cause increased cancer rates. Hopefully the awareness of such dangers will cause people to increase their own protection against the harmful UV rays of the sun. I know that I have noticed sunscreens that are now protecting against both UV-B and UV-A rays, which will definitely be beneficial in decreasing the sun damage that people sustain. I know that I have been hounded from an early age to apply and re-apply sunscreen all of the time. In fact, my parents sent me off the San Diego Freshman year with about five bottles of SPF 70.

Green Chemitry Application: TAMLs Catalyst

As a catalyst for cleaning, tetra-amindo macrcyclic ligand activators (TAMLs) have been explored to possibly destroy stubborn pollutants by accelerating hydrogen peroxide cleansing reactions. This is a very important application of chemistry because it shows how green chemistry can lessen some of the damage to the environment caused by traditional chemistry.

Benefits of TAML studies:

-applying the catalyst to waste water can reduce staining and hazardous chemicals. (greatly reduce smells and colors)
-the catalyst could possibly be used in the future to disinfect drinking water
-the catalyst could possibly be used to clean up bioterror attack contamination

If broadly adopted it is speculated that TAMLs could save millions of dollars in cleanup costs.

A DNA Nerd in an Environmental Chemistry Class

The first blog of the semester…well, let’s give this a try!

Given my research background with DNA, I was very intrigued when I read the portion of the Baird text that mentioned UV-B-induced mutations of DNA sequences (pg. 33-34). I’m sure we’re all aware that one of the effects of chronic UV radiation exposure is skin cancer, so DNA mutation probably isn’t all that shocking to read about. What was interesting, though, was how the DNA is mutated. Take a look at this picture!

Image created by David Herring (NASA)

Here’s a more chemical view of what the mutations can look like; keep in mind, these are bases that are staking along the phosphate backbone, not bases across the strand from one another:

As can be seen in the picture above, the two major products of UV mutation are 6,4 photoproducts and cyclobutane pyrimidine dimers (CPD), respectively. CPD mutations only occur when UV radiation strikes a sequence with consecutive pyrimidines (C’s or T’s) and induces the formation of covalent linkages. Despite the fact that CPDs are usually recognized by DNA repair enzymes, mutation correction is not 100% efficient, so these damaged sequences can persist. That’s one of the reasons why chronic exposure to UV-B radiation is so dangerous.

I personally thought it was interesting to get a little more of an in-depth look at what a depletion of the ozone layer can lead to on the molecular level. Ozone isn’t particularly good at absorbing radiation at 300 nm, which is the wavelength that wreaks the most havoc on DNA, but a little is better than nothing!

If any of you are interested, here’s a link to a Web Book that has a bit more of a mechanistic approach to showing DNA mutation by UV radiation.

Your planetary dashboard

Every wonder how quickly the planet is changing? Visit Worldometers to watch the population increase, topsoil disappear, and a host of other changes simulated in real time.