The Journal of Bacteriology is celebrating its centennial this year – one hundred years of valuable scientific discoveries! To illustrate the wide variety of noteworthy results published over the years, the journal is publishing a Classic Spotlight series, in which experts in the field highlight some of their favorite studies from past decades. Subjects covered so far include quorum sensing, fruiting bodies, biofilms, bacteriophage, and even the discovery of a second membrane around Gram-negative bacteria – all important core microbiology concepts. And we’re not even a quarter through 2016 yet!
In a new Editorial by Katrina Forest and Ann Stock, the discovery of penicillin is discussed – a notable milestone in our fight against infectious diseases. After its initial discovery by Alexander Fleming, the drug needed to be manufactured at a large enough scale before it could be distributed to sick individuals. Many scientific breakthroughs led to the ability to produce mass quantities, and the editorial highlights two: the discovery of naturally high volume-producing Penicillium notatum strains and the ability to purify penicillin from submerged cultures, rather than rely on surface-grown fungi.
The discovery of good penicillin-producing strains by Kenneth Raper, Dorothy Alexander, and Robert Coghill in 1944 involved tenacity and serendipity. They surveyed rotting fruit from produce markets in search of a more potent Penicillium species (hence the cover image, above left, of the current issue, illustrating a technician examining a cantaloupe). 241 strains were tested qualitatively for their ability to inhibit Staphylococcus growth, resulting in now-standard zones of inhibition (see figure, right). All the plugs were transferred and characterized by hand; as the Editorial indicates, this was high-throughput research in the 1940s!
Laboratory-scale production, described in 1945 by Andrew Moyer and Robert Coghill, addressed the problem of the time- and resource-expensive procedure of penicillin purification. This research used the strain described in the Raper study to test the effects of culture conditions on penicillin production. They found the optimal conditions for submerged cultures differed from those of surface cultures, and were then able to apply these conditions for industrial production of penicillin in tanks.
For more Classic Spotlights on seminal microbiology findings, stay tuned to mBiosphere and the Journal of Bacteriology!
-- Julie Wolf