E-Mail Connections are crucial. Bacteria may be most dangerous when they connect - banding together to build fortress-like structures known as biofilms that afford them resistance to antibiotics. But a biomolecular scientist in Israel and a microbiologist in California have forged their own connections that could lead to new protocols for laying siege to biofilm-protected colonies. Their research was published in the Proceedings of the National Academy of Sciences ( PNAS), USA. This interdisciplinary collaboration began with a lecture given at the Weizmann Institute of Science in the Life Sciences Colloquium. Prof. Dianne Newman of the California Institute of Technology was the speaker, and the Institute's Prof. Sarel Fleishman, of the Biomolecular Sciences Department, decided to attend, even though the lecture had no immediately apparent bearing on his own research. Newman described an enzyme she had discovered that could interrupt the metabolism of the biofilm-building bacteria, Pseudomonas aeruginosa. The enzyme interferes with the functioning of a molecule (pyocyanin) that is generated by the bacteria as they reach a high cell density and start to run out of oxygen, and it is thus responsible for helping bacteria deep within the biofilm remain viable as well as better tolerate conventional antibiotics. This molecule, however, is a double-edged sword: It can also be toxic to P. aeruginosa in the outer layers of the biofilm, where oxygen is present. Since pyocyanin impacts both biofilm development and antibiotic tolerance, Newman's lab focused on identifying ways to disrupt its activities. Newman's only problem, she said, was that the newly discovered pyocyanin-blocking enzyme was unstable and produced in minute amounts, and thus far, standard lab methods for growing such proteins had not been successful.