Almost every high school student has heard the story of how Alexander Fleming discovered penicillin by accident and changed the whole world. Now scientists have sequenced the genome of the mould that led him to his path-breaking discovery.
In case you haven’t heard it, here’s the story. In 1928, Fleming, a Scottish microbiologist and physicist, went on a vacation, leaving his lab unattended. When he returned, he found mould growing on one of his Petri dishes, possibly some contamination. He also found that the fungal growth had apparently destroyed all the staphylococci on his dishes and therefore, the world discovered penicillin.
Now, 92 years later, the mould is finally being sequenced. The discovery of the sequence could potentially help find the answer to antibiotic-resistance.
“Remarkably after all this time spent in the freezer, it grows back fairly readily. It is fairly easy, you just break it out of that tube and put it on a petri dish plate and away it goes,” Tim Barraclough, one of the scientists involved with the study was quoted saying on CNN. He is a professor at the Department of Life Sciences at Imperial College London and the Department of Zoology at Oxford University.
He said it was quite surprising that despite all the medical advancements brought on by the penicillin, no one had ever sequenced the original mould. The team used frozen mould that has been inside the freezer for decades and contains around 30,000 different strains of various microorganisms.
Currently, two major strains of Penicillium are used in the United States to mass-produce the antibiotic. The researchers compared genetic information of these two strains with the original mould’s DNA, the one used by Fleming.
They studied two genes in particular. One, coding enzyme that induces penicillin production in the fungus. Second, those that control this enzyme. The whole study can be found in the journal Scientific Reports.
With persistent usage over the decades, many bacteria have evolved to be antibiotic-resistant. When this happens, traditionally known penicillin or other antimicrobial compounds can’t kill the bacteria or cure the person of the disease. Barraclough believes studying the evolution through the current genome and original mould might help them understand how to modify the current production to help kill superbugs.