From Los Angeles, at the annual meeting of the American Society for Microbiology
With shapes reminiscent of the Apollo lunar landers, viruses called bacteriophages settle
onto a bacterium and inject their genes. This viral DNA makes the bacterium churn out new
copies of the phages, as well as an enzyme that destroys the bacterium’s cell wall so that the
phages can spread to other bacteria.
While some scientists are trying to use phages to control bacterial infections (SN: 6/3/00,
p. 358: Viruses that slay bacteria draw new interest), Vincent A. Fischetti of the Rockefeller University in New York and his colleagues have
turned to the wall-destroying enzyme itself. They’ve purified the protein, known as lysin, from
the debris of phage-infected Streptococcus pyogenes and have shown that the enzyme alone
can destroy bacteria in laboratory dishes.
The investigators have also coated the throats of mice with a solution of lysin and found
that it prevents Streptococcus bacteria from establishing an infection. The enzyme had no
apparent effect on the harmless bacteria that normally inhabit the rodent throat, adds
Rockefeller’s Daniel C. Nelson.