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Influence of Streptococcus mutans on the matrix assembly during the development of microcosm biofilms exposed to nutritional challenge

Grant number: 17/26623-5
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): April 01, 2018
Effective date (End): January 31, 2021
Field of knowledge:Health Sciences - Dentistry
Principal researcher:Marlise Inêz Klein Furlan
Grantee:Elkin Jahir Florez Salamanca
Home Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil


Biofilms are complex and dynamic forms of life, formed by several microorganisms that are organized as immersed cell communities and surrounded by hydrated extracellular polymeric substances, which assembly a three-dimensional structure known as Extracellular Matrix (ECM). Streptococcus mutans species is considered one of the main etiological agents of dental caries. In general, in vitro biofilm models used will never be able to completely reproduce the natural environment and at the same time control all parameters that can influence microbial growth. Among the proposed models, the microcosm model has been shown to better mimic the natural occurring biofilms because it starts from an inoculum of human microbiota (e.g., saliva). Thus, the objective of this study is to develop, standardize and characterize two microcosm biofilm models one biofilm formed by constant re-inoculations of saliva and one biofilm with a single saliva inoculum subjected to intermittent exposure to "fast and famine" nutritional challenges to emulate carbohydrate ingestion (sucrose and starch). Once these models are established, the contribution of S. mutans on the ECM assembly and cariogenic biofilm formation will be investigated. Therefore, the two biofilm models will be grown on bovine enamel surface to investigate: 1) the population dynamics of microbial species as the biofilm develops, becomes mature and cariogenic to identify when S. mutans start to influence the development of these biofilms becoming predominant to orchestrate the construction of the ECM; this experimental step will be achieved by sequencing to determine the microbial quantity and diversity; 2) the composition of the main components of the ECM (exopolysaccharides, lipoteichoic acids, extracellular DNA) using biochemical methods; 3) the expression of S. mutans genes associated with ECM construction and its survival and maintenance in biofilms via RT-qPCR; 4) the profile of enamel demineralization caused by the two models under study will be evaluated by microhardness and topography analyses. To interpret the results, statistical tests will be applied according to distribution adopting 5% significance level. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
FLOREZ SALAMANCA, ELKIN JAHIR; DANTAS, RAYSSA MARIANA; RODRIGUEZ, MARTHA JULIANA; KLEIN, MARLISE INEZ. Establishment of microcosm biofilm models that reproduce a cariogenic diet intake. BIOFOULING, DEC 2020. Web of Science Citations: 0.
CASTILLO PEDRAZA, MIDIAN C.; DE OLIVEIRA FRATUCELLI, ERICK DANTE; RIBEIRO, SABRINA MARCELA; FLOREZ SALAMANCA, ELKIN JAHIR; COLIN, JAQUELINE SILVA; KLEIN, I, MARLISE. Modulation of Lipoteichoic Acids and Exopolysaccharides Prevents Streptococcus mutans Biofilm Accumulation. Molecules, v. 25, n. 9 MAY 2020. Web of Science Citations: 0.

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