Secrets of a Salty Survivor

Well, one article on cancer is more than enough for me. An important part of our chapter was learning about DNA repair. DNA repair is necessary to minimize damage caused by mutations. There were several methods of DNA repair that we discussed in class, including direct repair, nucleotide excision repair, and methyl-directed mismatch repair. In this article, the author talks about a microbe called Halobacterium (pictured below) from the Dead Sea that has a highly developed DNA repair system.

Research into this topic can potentially help protect astronauts from DNA damage that results from interplanetary space radiation. As we learned in class, DNA molecules are sensitive to radiation. According to a researcher studying Halobacterium, her research group fragmented the bacteria's DNA completely through radiation only to find that it had reassembled its chromosome to working condition in several hours. Um, whoa!

Naturally, Halobacteria live in the extremely salty conditions of the Dead Sea (which is actually a lake), where most sea life would find inhospitable. This is because the salt causes the DNA to become damaged and even die in normal organisms because the extreme saltiness would lead to the same lesions as those created by exposure to radiation. In a series of experiments funded by NASA, researchers subjected this bacteria to the most dangerous form of UV radiation, and 80% of the bacteria survived while other bacteria, such as E. coli, would have been completely obliterated.

Each dot represents a gene while the color of each dot represents the level of activity

A DNA microarray (pictured above) was created to fully picture the response of Halobacteria to radiation. In response to radiation, a set of pre-created repair enzymes quickly began to repair the DNA, after which more repair enzymes were produced. This bacteria has several DNA repair mechanisms, some of which are similar to plant, animal, Archaeal, and other bacterial repair methods. 

Studies such as these can help researchers determine how DNA repair functions in humans and how it could possible by enhanced.