title: Arginine-Ornithine Antiporter ArcD Controls Arginine Metabolism and Interspecies Biofilm Development of Streptococcus gordonii.
abstract: Arginine is utilized by the oral inhabitant Streptococcus gordonii as a substrate of the arginine deiminase system (ADS), eventually producing ATP and NH3, the latter of which is responsible for microbial resistance to pH stress. S. gordonii expresses a putative arginine-ornithine antiporter (ArcD) whose function has not been investigated despite relevance to the ADS and potential influence on inter-bacterial communication with periodontal pathogens that utilize amino acids as a main energy source. Here, we generated an S. gordonii ΔarcD mutant to explore the role of ArcD in physiological homeostasis and bacterial cross-feeding. First, we confirmed that S. gordonii ArcD plays crucial roles for mediating arginine uptake and promoting bacterial growth, particularly under arginine-limited conditions. Next, metabolomic profiling and transcriptional analysis of the ΔarcD mutant revealed that deletion of this gene caused intracellular accumulation of ornithine leading to malfunction of the ADS and suppression of de novo arginine biosynthesis. The mutant strain also showed increased susceptibility to low pH stress due to reduced production of ammonia. Finally, accumulation of Fusobacterium nucleatum was found to be significantly decreased in biofilm formed by the ΔarcD mutant as compared with the wild-type strain, although ornithine supplementation restored fusobacterium biovolume in dual-species biofilms with the ΔarcD mutant and also enhanced single species biofilm development by F. nucleatum. Our results are the first direct evidence showing that S. gordonii ArcD modulates not only alkali and energy production but also interspecies interaction with F. nucleatum, thus initiating a middle stage of periodontopathic biofilm formation, by metabolic cross-feeding.
authors.affiliation: From the Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871 and.
authors.forename: Akito
authors.initials: A
authors.lastname: Sakanaka
authors.affiliation: From the Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871 and CREST, Japan Science and Technology Agency, Saitama 332-0012, Japan kuboniwa@dent.osaka-u.ac.jp.
authors.forename: Masae
authors.initials: M
authors.lastname: Kuboniwa
authors.affiliation: From the Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871 and.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takeuchi
authors.affiliation: From the Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871 and.
authors.forename: Ei
authors.initials: E
authors.lastname: Hashino
authors.affiliation: From the Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871 and.
authors.forename: Atsuo
authors.initials: A
authors.lastname: Amano
mesh_terms: D026905:Amino Acid Transport Systems / Q000235:genetics / Q000378:metabolism*; D017920:Antiporters / Q000235:genetics / Q000378:metabolism*; D001120:Arginine / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D016967:Fusobacterium nucleatum / Q000502:physiology; D017353:Gene Deletion; D006801:Humans; D056265:Microbial Interactions; D009952:Ornithine / Q000378:metabolism; D013290:Streptococcal Infections / Q000382:microbiology*; D054773:Streptococcus gordonii / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
chemical_list: D026905:Amino Acid Transport Systems; D017920:Antiporters; C063930:ArcD protein, Bacteria; D001426:Bacterial Proteins; D001120:Arginine; D009952:Ornithine
keywords: Fusobacterium; Streptococcus; arginine metabolism; biofilm; cell metabolism; cross-feeding; metabolic regulation; metabolomics; ornithine export; symbiosis