'Flu Vaccination' Protects Bacteria Against Virus

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'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.

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