Interspecies Signaling between Veillonella atypica and Streptococcus gordonii Requires the Transcription Factor CcpA

Streptococcus gordonii and Veillonella atypica, two early-colonizing members of the dental plaque biofilm, participate in a relationship that results in increased transcription of the S. gordonii gene amyB, encoding an -amylase. We show that the transcription factor CcpA is required for this interspecies interaction. Human dental plaque is a well-recognized example of a mul-tispecies bacterial community and a site of interspecies cell-cell interactions. These interactions include physical contacts medi-ated by molecules on the surfaces of bacterial cells, known as coaggregation, as well as metabolic interactions that have an ef-fect on growth and gene expression (8, 9). Two early-colonizing oral bacteria, Streptococcus gordonii and Veillonella atypica, un-dergo such interactions. Fermentation of sugar by S. gordonii produces lactic acid, a substrate for energy generation by V. atypica. During coculture growth of S. gordonii and V. atypica, a signaling event that results in increased transcription of the S. gordonii gene amyB, encoding an -amylase, occurs (4). We hav