"Biofilms are responsible for corrosion of metals in water pipes and on marine vessels," he noted, adding that bacterial biofilm can be 1,000 times more resistant to antibiotics than solitary organisms a problem that is especially acute in long-term catheters, artificial heart valves and other medical implants, where the accumulation of slime often results in serious infections.

"But not everything related to biofilms is harmful," added Spormann. "They also play an important part in the ecosystem of soils and sediments, and are beneficial in bioremediation of soil and water sites contaminated with toxic substances."

Microbial communities Researchers long have been fascinated with the communal nature of biofilms. Once imbedded in their slimy matrix, solitary bacteria turn on a unique set of genes that allows them to signal each other as well as hundreds of different microbial species including fungi and algae.

"They become metabolically codependent inside the matrix and begin talking to each other," Spormann explained. "They can even sense the density of how many friends are around them a process called quorum sensing."

In addition to enhancing their chance of survival, biofilms also provide ecological advantages to microorganisms, according to Spormann.

"By adhering to a wet surface, bacteria can wait for food to come by in the water," he noted."In fact, trickling filters in sewage treatment plants depend on biofilms to treat wastewater."

Spormann said the new confocal microscope located in Room 18 of the Terman Engineering Center will give researchers the ability to image living biofilms that are still attached to various surfaces.

"By understanding the basic science of
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Contact: Mark Shwartz
mshwartz@stanford.edu
650-723-9296
Stanford University
28-Nov-2001