Our image of the week depicts the mould Penicillium, which produces the antibiotic penicillin. Moulds are a type of fungus, and reproduce using the spores that you can see in the picture. The Penicillium mould in this particular image was growing on the surface of bread.
The image was taken by Debbie Marshall and David Gregory in 1983 using a scanning electron microscope (SEM). To capture it, they took a small sample of the mouldy bread and chemically fixed it to make it more stable for the microscopy procedure. It was then washed with distilled water and dehydrated using ethanol and carbon dioxide to make it completely dry. The bread samples were then mounted on aluminium stubs, attached with adhesive containing silver and coated with tiny (20 nanometre, or 0.00002mm) fragments of platinum to make them conductive. After this preparation, the SEM image could be taken. Colour was added to the image in 2003.
Earlier this week (6th August) would have been Alexander Fleming’s 132nd birthday. Alexander Fleming is credited with the serendipitous discovery of penicillin in 1928 when he found mould contaminating his sample of Staphylococcus bacteria. He noticed that no bacteria was growing around the mould and concluded that this mould (Penicillium notatum) produced something that stopped the growth of the bacteria. This substance was penicillin. Fleming wasn’t the first person to notice the bacteria-inhibiting properties of mould (ancient Greeks had used mould to treat infection and scientists in the 1870s noticed that bacteria didn’t grow around Penicillium), but it was the publication of his discovery that led to modern antibiotics. Fleming was awarded the Nobel Prize in medicine in 1945 “for the discovery of penicillin and its curative effect in various infectious diseases.”
Image credit: David Gregory & Debbie Marshall, Wellcome images.
Wellcome Images is one of the world’s richest and most unusual collections, with themes ranging from medical and social history to contemporary healthcare and biomedical science. All our images are available in digital form so please click the link above if you would like to use the picture that features in this post, or to quickly find related ones. Many are free to use non-commercially under the terms of a Creative Commons licence and full details of the specific licence for each image are provided.
Make us gasp with your images! We are always on the look out for striking images so if you are a research scientist, clinical photographer, or illustrator and have high quality imagery that relates to biomedical science or contemporary healthcare, we would love to see your work. Our collections span all artistic media and imaging techniques ranging from hand drawn illustrations to functional magnetic resonance imaging (fMRI) scans. What’s more, any images we receive before 30 September 2013 will be considered for the Wellcome Image Awards 2014. Email Sabrina Taner for more information about this.
Filed under: History of Medicine, Infectious Disease, Wellcome Images Tagged: Alexander Fleming, Bread, David Gregory, Debbie Marshall, Penicillin, SEM
