MSGID: 1:317/3 6482ab18   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Dentists identify new bacterial species involved in tooth decay    
    Large study in children reveals Selenomonas sputigena as a key partner of   
   Streptococcus in cavity formation.    
      
     Date:   
         June 8, 2023   
     Source:   
         University of Pennsylvania   
     Summary:   
         Large study in children reveals Selenomonas sputigena as a key   
         partner of Streptococcus in cavity formation.   
      
      
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   FULL STORY   
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   Philadelphia -- Collaborating researchers from the University of   
   Pennsylvania School of Dental Medicine and the Adams School of Dentistry   
   and Gillings School of Global Public Health at the University of North   
   Carolina have discovered that a bacterial species called Selenomonas   
   sputigena can have a major role in causing tooth decay.   
      
   Scientists have long considered another bacterial species, the   
   plaque-forming, acid-making Streptococcus mutans, as the principal cause   
   of tooth decay -- also known as dental caries. However, in the study,   
   which appeared 22 May in Nature Communications, the Penn Dental Medicine   
   and UNC researchers showed that S.   
      
   sputigena, previously associated only with gum disease, can work as a   
   key partner ofS. mutans, greatly enhancing its cavity-making power.   
      
   "This was an unexpected finding that gives us new insights into the   
   development of caries, highlights potential future targets for cavity   
   prevention, and reveals novel mechanisms of bacterial biofilm formation   
   that may be relevant in other clinical contexts," said study co-senior   
   author Hyun (Michel) Koo DDS, PhD, a professor in the Department of   
   Orthodontics and Divisions of Pediatrics and Community Oral Health and   
   Co-Director of the Center for Innovation & Precision Dentistry at Penn   
   Dental Medicine.   
      
   The other two co-senior authors of the study were Kimon Divaris, PhD,   
   DDS, professor at UNC's Adams School of Dentistry, and Di Wu, PhD,   
   associate professor at the Adams School and at the UNC Gillings School   
   of Global Public Health.   
      
   "This was a perfect example of collaborative science that couldn't   
   have been done without the complementary expertise of many groups and   
   individual investigators and trainees," Divaris said.   
      
   Caries is considered the most common chronic disease in children and   
   adults in the U.S. and worldwide. It arises when S. mutans and other   
   acid-making bacteria are insufficiently removed by teeth-brushing and   
   other oral care methods, and end up forming a protective biofilm, or   
   "plaque," on teeth. Within plaque, these bacteria consume sugars from   
   drinks or food, converting them to acids. If the plaque is left in place   
   for too long, these acids start to erode the enamel of affected teeth,   
   in time creating cavities.   
      
   Scientists in past studies of plaque bacterial contents have identified   
   a variety of other species in addition to S. mutans. These include   
   species of Selenomonas, an "anaerobic," non oxygen-requiring group of   
   bacteria that are more commonly found beneath the gum in cases of gum   
   disease. But the new study is the first to identify a cavity-causing   
   role for a specificSelenomonas species.   
      
   The UNC researchers took samples of plaque from the teeth of 300 children   
   aged 3-5 years, half of whom had caries, and, with key assistance   
   from Koo's laboratory, analyzed the samples using an array of advanced   
   tests. The tests included sequencing of bacterial gene activity in the   
   samples, analyses of the biological pathways implied by this bacterial   
   activity, and even direct microscopic imaging. The researchers then   
   validated their findings on a further set of 116 plaque samples from 3   
   to 5-year-olds.   
      
   The data showed that although S. sputigena is only one of several   
   caries-linked bacterial species in plaque besides S. mutans, and does   
   not cause caries on its own, it has a striking ability to partner with   
   S. mutans to boost the caries process.   
      
   S. mutansis known to use available sugar to build sticky constructions   
   called glucans that are part of the protective plaque environment. The   
   researchers observed that S. sputigena, which possesses small appendages   
   allowing it to move across surfaces, can become trapped by these   
   glucans. Once trapped, S.   
      
   sputigena proliferates rapidly, using its own cells to make   
   honeycomb-shaped "superstructures" that encapsulate and protect   
   S. mutans. The result of this unexpected partnership, as the researchers   
   showed using animal models, is a greatly increased and concentrated   
   production of acid, which significantly worsens caries severity.   
      
   The findings, Koo said, show a more complex microbial interaction than   
   was thought to occur, and provide a better understanding of how childhood   
   cavities develop -- an understanding that could lead to better ways of   
   preventing cavities.   
      
   "Disrupting these protective S. sputigena superstructures using specific   
   enzymes or more precise and effective methods of tooth-brushing could   
   be one approach," Koo said.   
      
   The researchers now plan to study in more detail how this anaerobic   
   motile bacterium ends up in the aerobic environment of the tooth surface.   
      
   "This phenomenon in which a bacterium from one type of environment moves   
   into a new environment and interacts with the bacteria living there,   
   building these remarkable superstructures, should be of broad interest   
   to microbiologists," Koo said.   
      
   "Selenomonas sputigena acts as a pathobiont mediating spatial structure   
   and biofilm virulence in early childhood caries" was co-authored by   
   Hunyong Cho, Zhi Ren, Kimon Divaris, Jeffrey Roach, Bridget Lin, Chuwen   
   Liu, M. Andrea Azcarate-Peril, Miguel Simancas-Pallares, Poojan Shrestha,   
   Alena Orlenko, Jeannie Ginnis, Kari North, Andrea Ferreira Zandona,   
   Apoena Aguiar Ribeiro, Di Wu and Hyun "Michel" Koo.   
      
   The work was funded in part by the National Institutes of Health   
   (U01DE025046, R01DE025220, R03DE028983).   
      
       * RELATED_TOPICS   
             o Health_&_Medicine   
                   # Dentistry # Diseases_and_Conditions # Medical_Topics #   
                   Children's_Health   
             o Plants_&_Animals   
                   # Bacteria # New_Species # Microbes_and_More #   
                   Microbiology   
       * RELATED_TERMS   
             o Developmental_psychology o Diaphragm_(anatomy) o   
             Developmental_biology o Central_nervous_system o Middle_ear   
             o Glutamic_acid o Streptococcus o Radiography   
      
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   Story Source: Materials provided by University_of_Pennsylvania. Note:   
   Content may be edited for style and length.   
      
      
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   Journal Reference:   
      1. Hunyong Cho, Zhi Ren, Kimon Divaris, Jeffrey Roach, Bridget M. Lin,   
         Chuwen Liu, M. Andrea Azcarate-Peril, Miguel A. Simancas-Pallares,   
         Poojan Shrestha, Alena Orlenko, Jeannie Ginnis, Kari E. North,   
         Andrea G.   
      
         Ferreira Zandona, Apoena Aguiar Ribeiro, Di Wu, Hyun   
         Koo. Selenomonas sputigena acts as a pathobiont mediating spatial   
         structure and biofilm virulence in early childhood caries. Nature   
         Communications, 2023; 14 (1) DOI: 10.1038/s41467-023-38346-3   
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   Link to news story:   
   https://www.sciencedaily.com/releases/2023/06/230608120924.htm   
      
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