Washington, Nov 19 (IANS) Viruses invade both humans and animals, but some of them target bacteria instead. Potentially, that opens up new ways to treat bacterial infections, says a new study.

Texas A&M University researchers are exploring how hungry viruses, armed with transformer-like weapons, attack bacteria.

The attackers are called phages, derived from the Greek 'phagein', or bacteriophages, meaning eaters of bacteria.

'The phages first attach to the bacteria and then inject their DNA,' says Sun Qingan, study co-author and doctoral student at Texas A&M. 'Then they reproduce inside the cell cytoplasm.'

After more than 100 phage particles have been assembled, the next step is to be released from the bacterial host, so that the virus progeny can find other hosts and repeat the reproduction cycle, Sun adds.

Besides the cell membrane, the phages have another obstacle on their way out -- a hard shell called cell wall that protects the bacteria. Only by destroying the cell wall can the phages release their offspring.

But the phages deploy a secret weapon -- an enzyme that can destroy the wall from inside, called endolysin, says a Texas A&M release.

The trigger controlling this transformation process is a segment of the enzyme called the SAR domain, according to the researchers.

'The SAR domain is like the commander -- it tells the enzyme when to begin restructuring and destroying the cell wall,' Sun says.

'This finding enables us to better understand the release process and provides us with a possible target when we want to control the destruction of bacteria cell walls or prohibit this action in some infectious diseases.'