title: Involvement of two-component signal transduction system, ComDE, in the regulation of growth and genetic transformation, in the ruminal bacterium Streptococcus bovis.
abstract: In ruminants, Streptococcus bovis is considered to be associated with acute rumen acidosis. To elucidate the regulatory mechanisms of S. bovis growth, we investigated the function of the two components of the peptide pheromone-signaling system, ComD and ComE, which are encoded by comD and comE, respectively, via the competence-stimulating peptide ComC, which is encoded by comC. Deletion of entire comC and two-thirds of comD resulted in decreased growth rate, which may be related to the change in the expression of several proteins, as shown by two-dimensional gel electrophoresis. The transcript level of comED was decreased by the disruption of comCD, suggesting that the transcription of comED might be stimulated by ComC. The transformation frequency was decreased by the disruption of comCD. Addition of recombinant ComC to S. bovis cultures increased the growth rate and transformation frequency. In the cultures of mixed ruminal microbes, addition of mature ComC peptide increased the number of S. bovis per total bacterial counts as estimated by the cDNA amounts of 16SrRNA. Thus, the peptide pheromone-signaling system via ComC, D, and E might be involved in the control of S. bovis growth in addition to competence development. This is the first report suggesting that an autoinducing peptide functions in the ruminal ecosystem.
authors.affiliation: Department of Life Science, College of Agriculture, Meiji University, Higashimita, Tama-ku, Kawasaki, Japan. asanuma@isc.meiji.ac.jp
authors.forename: Narito
authors.initials: N
authors.lastname: Asanuma
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yoshii
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kanada
authors.forename: Kimio
authors.initials: K
authors.lastname: Yoshizawa
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Arai
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Akiko
authors.initials: A
authors.lastname: Kawamura
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Hino
mesh_terms: D058491:Bacterial Load; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005816:Genetic Complementation Test; D020543:Proteome / Q000032:analysis; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D015398:Signal Transduction; D016985:Streptococcus bovis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; D020543:Proteome; D012329:RNA, Bacterial; D012333:RNA, Messenger; C423628:competence factor, Streptococcus