Free-floating DNA molecules strengthen and help to confer helical shapes within the extracellular polysaccharide matrix of Pseudomonas aeruginosa biofilms, according to microbiologist Daniel Wozniak of Ohio State University (OSU), Columbus, and his collaborators. Thus Psl, the main polysaccharide of the matrix, forms helical structures that stabilize cell-cell interactions within the biofilm and also its attachments to underlying and adjacent surfaces.

Even if recognizing that microorganisms cause bad breath and "most" other bad odors, microbiologists who study odor makers have "never gotten together, and we're not sharing information on how to sample and characterize [these phenomena]," says Mel Rosenberg of Tel-Aviv University in Tel-Aviv, Israel.

 Microorganisms moved from being exclusively marine species to living also on land much earlier than thought-about 2.75 billion instead of the widely accepted 1.2 billion years ago, according to Birger Rasmussen from the Curtin University of Technology in Bentley, Australia, and his collaborators.

Listeria monocytogenes bacterial cells, although harmless when inhabiting soil or water, undergo a marked shift in gene expression that makes them potentially deadly when ingested as food contaminants.