The Dirt on Drugs

Although there are many antibiotics available, infectious diseases are still a leading cause of death worldwide. Some of the antibiotics are not able to cure the disease due to mutations in the infectious microbe. Scientists have found a way to make antibiotics by extracting DNA from different types of soil.

The process from being soil to being medication is quite interesting. First, the soil is collected along with any relevant data to the soil and its location. Once the soil sample reaches the laboratory, scientist will extract DNA present in the sample. After that, the scientists will use targeted PCR to amplify  the biosynthetic domains, which are then sequenced. The sequence is then analyzed and added to a database, and the data is released on Drugs from Dirt website, where it will show which molecules were in the sample.

A team of Rockefeller scientists may have potentially found a cure for tuberculosis. The microbe that causes the tuberculosis, Mycobacterium, currently resists any antibiotics used to cure it, such as rifamycin, by mutating in a way to resist being treated. Rifamycin (Rif) attempts to cure TB by targeting the RNA polymerase, but the microbe starts to resist when the genes coding for RNAP mutate; any small genetic change can cause Rif to not be able to function. The team of scientists found a natural antibiotic found in soil, kanglemycins (kangs), whose genes are similar to Rif’s genes but has some small differences that allows it to bind to the RNA polymerase. After testing this new antibiotic, the scientists found that kangs contained features attached to the core, like extra acids and sugars, which allowed kangs to bind to the RNA polymerase in a new way and target bacteria that Rif was not able to, making kangs a more powerful antibiotic.

Another team of scientists compared genetic sequencing data with environmental data at sites to identify how factors, like soil pH, geographic location, and latitude, compared to the changes in composition. At each site, they recorded latitude, longitude, altitude, soil pH, as well as yearly rainfall and average temperature. After analyzing 397 samples from 16 different ecotypes, they found that there was a very small correlation between biosynthetic domain richness and any of the environmental factors measured. The most change in biosynthetic domain composition were with different latitudes, but they still need more in-depth analysis of other environmental variables to confirm any conclusions other than that the more biosynthetic gene cluster diversity will help in the future natural product discoveries.

If you are curious on what antibiotics might be in your yard, Drugs from Dirt has an opportunity for people from around the world to help them with their discoveries, called the Citizen Science program. This program is interested in teaming up with schools and science classes to create a curriculum around this program. On the website there is a google form to fill out, where it will ask about some details on the location, and then it has instructions on how to send them a soil sample.

About Mr. Mohn

Biology Teacher

This entry was written by Amisha T. and tagged . Bookmark the permalink.

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