Abstrait

Isolation and characterisation of Bacteriophages: A systematic protocol.

Oluwafunmilola Adepoju

Bacteria as well as other organisms are subject to infection by viruses. This was realized when Frederick Twort I 1915 in England an Felix d’Herelle in 1917 in Paris independently observed the phenomenon of the transmissible lysis of bacteria. Twort observed that Micrococcus colonies sometimes underwent lysis and that this lytic effect could be transmitted from colony to colony even at high dilution of material from a lysed effect. However, heating the filtrate destroyed its lytic property from this observation. Twort cautiously suggested that the lytic agent might be a viruses. This was also demonstrated by d’Herelle in the following experiment a few drops of liquid faeces from a case of bacterial dysentery were added to a tube of broth which was incubated overnight; filtration of this culture through a porcelain candle yielded a bacteria – free filtrate which, when added in very small quantities to a young culture of Shigella shigae produced clearing and lysis of the bacterium after incubation for several hours. D’Herelle was able to show that this lysed culture possessed a similar lytic property towards a fresh culture and he was able to carry the effect through more than fifty successive transfers, he thought the effect was caused by “an invisible microbe that is antagonistic to the dysentery bacillus and suggested that this was a minute parasite of the bacteria propagating and multiplying at the expense of the bacterial cells. He called the microbe “Bacteriophage” which means “bacteria eater” a named now frequently abbreviated to phage and this view that the agent was a virus has been fully confirmed.