Scientists believe this will help to optimize drug production and aid the study of antibiotic-resistant bacteria.
In 1928, British biologist Alexander Fleming accidentally discovered penicillin when fungi of the genus Penicillium began to grow in a Petri dish filled with bacteria.
Now, in 2020, researchers at Imperial College London and the University of Oxford, both in the UK, have sequenced for the first time the genome of the mold that originally led to the discovery of the first antibiotic in history.
The experts used samples of the initial microorganism that have been preserved until today, in addition to two strains of Penicillium from the United States used to produce the antibiotic on an industrial scale.
The results were recently published in the journal Scientific Reports.
“We originally set out to use Alexander Fleming’s fungus for some different experiments, but we realised, to our surprise, that no-one had sequenced the genome of this original Penicillium, despite its historical significance to the field,” said study leader Timothy Barraclough, from the Department of Life Sciences at Imperial and the Department of Zoology at Oxford.
Although Fleming’s mold is famous for being the original source of penicillin, industrial production quickly switched to moldy melon fungi in the United States.
From this, the Penicillium samples were artificially selected for strains that produced higher volumes of the antibiotic.
After sequencing the DNA of three types of the fungus, the researchers analyzed two types of genes in particular: those that encode the enzymes that the fungus uses to produce penicillin; and those that regulate enzymes, for example, by controlling how much enzymes are produced.
The genes encoding penicillin-producing enzymes differ between isolated strains, suggesting that wild mold varied naturally over time.
Although they don’t know exactly how, the researchers believe the findings may help in the development of new antibiotics, making them more abundant and effective.
“Our research could help inspire novel solutions to combatting antibiotic resistance,” said co-author Ayush Pathak, from the Department of Life Sciences at Imperial.
According to him, industrial production focuses on the amount of penicillin produced and the steps used to artificially improve production.
“But it is possible that industrial methods might have missed some solutions for optimising penicillin design,” Pathak said. “We can learn from natural responses to the evolution of antibiotic resistance.”