MiAh Kim
Chonbuk National University,Republic of Korea
Title: Characterization of the effects of S. mutans growth conditions on eDNA release
Biography
Biography: MiAh Kim
Abstract
Background: Extracellular DNA (eDNA) is a component of the biofilm matrix, which also includes microbial cells, exopolysaccharides, and proteins. Although many studies have examined eDNA, there is little information available regarding Streptococcus mutans eDNA.
Methods: To characterize S. mutans eDNA, we cultured the bacteria for 1 to 24 h in medium with 1% sucrose or 1% glucose. We identified eDNA by using polymerase chain reaction and used DNA-binding dye, SYBR green I to measure the amount of eDNA.
Results: We found that S. mutans eDNA has some differences from S. mutans genomic DNA, and that eDNA is secreted at an early growth stage (£ 1 h postinoculation). S. mutans produced more eDNA in the supernatant and less eDNA in the pellet in 1% glucose than in 1% sucrose. Although S. mutans cultured in 1% sucrose had more colony forming units (CFUs), the pH values were higher and the CFU-normalized eDNA levels were lower compared to S. mutans cultured in 1% glucose. DNase treatment removed eDNA and significantly reduced the total dry weight (2.6 fold in 1% glucose and 1.4 fold in 1% sucrose).
Conclusions: These results indicate that S. mutans produces different levels of eDNA in different media, and that eDNA is an important component aggregator in S. mutans biofilms.