Tag Archives: E. coli

Antibiotic resistance… the NEXT generation

MRSA- Picture courtesy of CDC's Public Health Image Library

MRSA- Picture courtesy of CDC’s Public Health Image Library

Antibiotic resistance is a growing- and serious- problem. Most antibiotics work by interfering with cell functions, but certain types of bacteria (like MRSA) have evolved in such a way that these antibiotics just won’t work. Researchers all over the world are working on this problem, and it seems that scientists at MIT have made a pretty significant breakthrough.

By using a genome-editing system called CRISPR, researchers have been able to target the genes that allow bacteria to resist antibiotics. And by targeting the genes responsible for antibiotic resistance and disrupting them, they were able to kill over 99% of the resistant bacteria. Using this method, they also successfully increased survival rates of waxworm larvae infected with a nasty form of E. coli.

Currently, research in mice is in progress. The goal is that one day, this technology could be modified to work on humans. As recent research hasn’t yielded many new classes of antibiotics, this method may ultimately play an important role in stopping the spread of antibiotic resistance in the human population.

Read more about it here: http://newsoffice.mit.edu/2014/fighting-drug-resistant-bacteria-0921

Evolution 1

E. coli gives researchers insight into evolution

E. coli showing evolution? Yes! Researchers at Michigan State University have been growing Escherichia coli for 25 years, which is over 58,000 generations, in a project called the Long-Term Experimental Evolution project. And during this time, through studying 12 populations of E. coli, they have found that the bacteria continues to adapt to its environment, with no upper limit in sight- even in the 40,00-50,000 generation range, E. coli‘s “fitness” (a measure of how the organism has adapted to its environment) increased by 3-4% per generation!

Another interesting find: several genetic changes that took place over thousands of generations allowed one of the E. coli colonies to develop the ability to eat the chemical citrate in the presence of oxygen (an ability that E. coli hasn’t had since the Miocene epoch!). Careful record-keeping allowed the researchers to look  back at previous generations and track the development of this ability.

Just a fun fact for you- it would take almost two and a half million years to look at 58,000 generations of humans. Bacteria and animals with short lifespans can give us incredible insights into genetic changes that we wouldn’t be able to see in humans.

http://www.the-scientist.com/?articles.view/articleNo/38325/title/Ever-Evolving-E–coli/

https://www.sciencenews.org/article/evolving-e-coli