Template:POTD/2020-05-24
A bacteriophage is a virus that infects and replicates within bacteria and archaea. Bacteriophages are among the most common and diverse entities in the biosphere, found wherever bacteria are present. Early evidence of their existence came when the English bacteriologist Ernest Hanbury Hankin reported in 1896 that something in the waters of the Ganges and Yamuna rivers in India had a marked antibacterial action against cholera, but was so minute that it could pass through a very fine porcelain filter.
This picture is a transmission electron micrograph at approximately 200,000× magnification, showing numerous bacteriophages attached to the exterior of a bacterium's cell wall.Photograph credit: Graham Beards