'Flu Vaccination' Protects Bacteria Against Virus

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http://www.sciencedaily.com/releases/2008/08/080814163649.htm

'Flu Vaccination' Protects Bacteria Against Virus

ScienceDaily (Aug. 15, 2008) — Bacteria – like people animals and plants –

can become infected by a virus. Researchers at Wageningen University,

together with colleagues from England and the United States, have unravelled

a mechanism with which bacteria can defend themselves for a longer period

against threatening viruses. Over the long term, this research offers

possibilities to protect bacteria used in industrial processes against viral

infections by giving them a 'flu vaccination'.

The researchers will publish their findings in the journal Science on 15

August.

The mechanism that bacteria use to protect themselves against viruses was

discovered last year. In an ingenious fashion, the bacteria build pieces of

viral DNA into their own DNA. The 'adopted' segment of DNA works like a

snapshot in a photo album, a type of memory that reminds the bacteria during

a subsequent encounter with the same virus. At that point, the viral DNA is

recognised, after which the bacteria set a system into operation that

ultimately leads to the breakdown of the virus. Until recently, the

operation of this system was a mystery.

The team of researchers from Wageningen, Sheffield (UK) and Bethesda (USA)

succeeded in unravelling the operation of this defence system. In recent

years, researchers Stan Brouns, Matthijs Jore, Magnus Lundgren and van

der Oost (Laboratory of Microbiology of Wageningen University) identified

six bacterial proteins involved in the defence system. These proteins help

the bacteria use the built-in virus fragment to prevent a virus infection.

The researchers determined that one of the proteins cuts the 'virus snapshot

out of the photo album, and together with the other five proteins, compares

the snapshot with the DNA of the invading virus. In the same way, other

viruses in the photo album can also be rendered harmless.

With this knowledge, it is theoretically possible to protect bacteria

against problematic viruses. This can be compared to a flu vaccination for

bacteria. Potential applications include industrial fermentation processes,

where bacteria that produce a useful substance are protected against viral

infection by means of a 'vaccination' . By reversing the process, the

protective mechanism of bacteria can also be deactivated. This could lead to

a strategy where viruses can be used to combat bacteria that have developed

an advanced form of antibiotic resistance, such as the hospital bacteria.

All animals, plants and bacteria run the risk of being infected by specific

viruses. For humans, such viruses include the flu virus, for the tobacco

plant this is the tobacco mosaic virus and for the intestinal bacterium E.

Coli this is the enterobacteria phage lambda. During the course of evolution

these organisms have developed systems to render viruses harmless. Viruses

respond by adapting themselves in such a way that they avoid the defence

mechanism, to which the bacteria respond in turn. In short, there is a

continuous arms race between bacteria and viruses.