Phenotypic adaptation in early bacterial colonizers on oral surfaces - an in vitro study

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Phenotypic adaptation in early bacterial colonizers on oral surfaces - an in vitro study

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Publication 2-year master student thesis
Title Phenotypic adaptation in early bacterial colonizers on oral surfaces - an in vitro study
Author(s) Hunfjörd, Sylvia ; Olsson, Jenny
Date 2016
English abstract
Oral bacteria, such as the early colonizers; Streptococcus gordonii, Streptococcus oralis, Streptococcus mitis and Actinomyces naeslundii display a wide range of surface adhesins which enable them to bind to receptors in the tooth pellicle. Saliva, gingival crevicular fluid (GCF) and collagen I in cementum on uncovered root surfaces present possible binding sites in the oral cavity onto which microorganisms can adhere and form a biofilm. The aim of this study was to assess whether these selected bacteria can alter their gene expression in response to protein components found on the various surfaces. In vitro laboratory assays were conducted, where the four oral species were added to surfaces coated with three substrates; human saliva, human serum and collagen I. The degree of induced proteolytic activity, surface-associated as well as secreted, was subsequently assessed using a FITC-labelled protease substrate, radial diffusion assays on skim milk agar and spectrophotometry. The hypothesis underlying the study was that bacterial species adapt depending on the surfaces they adhere to, thus altering protease expression. Based on the results, small variations could be detected, although no firm conclusion can be drawn regarding proteolytic abilities of the selected bacteria when exposed to the surfaces tested here.
Swedish abstract
Orala bakterier, såsom de tidiga kolonisatörerna; Streptococcus gordonii, Streptococcus oralis, Streptococcus mitis och Actinomyces naeslundii uttrycker ett brett spektrum av ytadhesiner som möjliggör inbindning till receptorer i tandpellikeln. Saliv, gingivalt exudat (GCF) och kollagen I i cement på blottade rotytor erbjuder möjliga ytor i munhålan där bakterier kan adherera och bilda biofilm. Syftet med denna studie var att undersöka huruvida utvalda bakterier kan förändra genuttryck beroende på innehållet i olika ytor. Laborativa in vitro-försök genomfördes där de fyra bakteriearterna tilläts växa på ytor täckta med de tre olika substrat; saliv, serum och kollagen I. Graden av inducerad proteolytisk aktivitet, yt-associerad såväl som utsöndrad, uppskattades därefter med hjälp av ett FITC-konjugerat substrat, radiell diffusionsteknik samt spektrofotometri. Enligt studiens hypotes skulle bakteriearterna anpassa sig beroende på ytan de fäste till, och därigenom ändra metabol aktivitet såsom proteasuttryck. Baserat på resultaten kunde små förändringar noteras. Dock kunde inga bestämda slutsatser dras vad gäller förändrad proteolytisk förmåga hos de utvalda bakterierna exponerade för de olika orala ytorna i studien.
Publisher Malmö högskola/Odontologiska fakulteten
Pages 23
Language eng (iso)
Subject(s) Proteolytic activity
Early colonizers
Handle http://hdl.handle.net/2043/20733 (link to this page)

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