title: Effect of estradiol on planktonic growth, coaggregation, and biofilm formation of the Prevotella intermedia group bacteria.
abstract: Alterations in the quantity and quality of biofilms at gingival margin are considered to play a role in the initiation and development of pregnancy-related gingivitis. Prevotella intermedia sensu lato is able to consume estradiol, the major sex hormone secreted during pregnancy, in the absence of vitamin K. The aim of the study was to examine the effect of estradiol on the planktonic growth, coaggregation, polysaccharide production, and biofilm formation of the P. intermedia group bacteria, namely P. intermedia, Prevotella nigrescens, and Prevotella pallens. In all experiments, the type strain (ATCC) and a clinical strain (AHN) of P. intermedia, P. nigrescens, and P. pallens were incubated with the concentrations of 0, 30, 90, and 120 nmol/L of estradiol. Planktonic growth was assessed by means of the colony forming unit method, while coaggregation and biofilm formation were assessed by spectrophotometric methods. In the determination of protein and polysaccharide levels, the Bradford and phenol-sulfuric acid methods were used, respectively. P. pallens AHN 9283 and P. nigrescens ATCC 33563 increased their numbers at planktonic stage with increasing estradiol concentrations. In 48-h biofilm tests, elevated protein levels were found for both strains of P. intermedia, and the strains P. nigrescens ATCC 33563 and P. pallens AHN 9283 in the presence of estradiol. The P. intermedia strains also increased the levels of polysaccharide formation in the biofilm. Coaggregation of the P. intermedia group organisms with Fusobacterium nucleatum was enhanced only in P. intermedia AHN 8290. In conclusion, our in vitro experiments indicate that estradiol regulates planktonic growth, coaggregation, polysaccharide production, and biofilm formation characteristics of P. intermedia, P. nigrescens, and P. pallens differently. These results may, at least partly, explain the differences seen in their contribution to the pathogenesis of pregnancy-related gingivitis.
authors.affiliation: Department of Periodontology, Institute of Dentistry, University of Turku, FI-20520 Turku, Finland. Electronic address: dareen.fteita@utu.fi.
authors.forename: Dareen
authors.initials: D
authors.lastname: Fteita
authors.affiliation: Department of Periodontology, Institute of Dentistry, University of Turku, FI-20520 Turku, Finland; Department of Infectious Disease Surveillance and Control, National Institute for Health and Welfare (THL), FI-00300 Helsinki, Finland. Electronic address: eija.kononen@utu.fi.
authors.forename: Eija
authors.initials: E
authors.lastname: Könönen
authors.affiliation: Department of Periodontology, Institute of Dentistry, University of Turku, FI-20520 Turku, Finland. Electronic address: eva.soderling@utu.fi.
authors.forename: Eva
authors.initials: E
authors.lastname: Söderling
authors.affiliation: Department of Periodontology, Institute of Dentistry, University of Turku, FI-20520 Turku, Finland. Electronic address: ulvi.gursoy@utu.fi.
authors.forename: Ulvi Kahraman
authors.initials: UK
authors.lastname: Gürsoy
mesh_terms: D000328:Adult; D001419:Bacteria; D001422:Bacterial Adhesion / Q000187:drug effects*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development*; D015169:Colony Count, Microbial; D004958:Estradiol / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D016967:Fusobacterium nucleatum / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D011247:Pregnancy; D018720:Prevotella / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology*; D011506:Proteins / Q000032:analysis; D013053:Spectrophotometry
chemical_list: D004967:Estrogens; D011135:Polysaccharides, Bacterial; D011506:Proteins; D004958:Estradiol
keywords: Biofilm; Coaggregation; Planktonic; Pregnancy; Prevotella; Sex hormone