Modulation of Lipoteichoic Acids and Exopolysaccharides Prevents Streptococcus mutans Biofilm Accumulation

Dental caries is a diet–biofilm-dependent disease. Streptococcus mutans contributes to cariogenic biofilms by producing an extracellular matrix rich in exopolysaccharides and acids. The study aimed to determine the effect of topical treatments with compound 1771 (modulates lipoteichoic acid (LTA) metabolism) and myricetin (affects the synthesis of exopolysaccharides) on S. mutans biofilms. In vitro S. mutans UA159 biofilms were grown on saliva-coated hydroxyapatite discs, alternating 0.1% sucrose and 0.5% sucrose plus 1% starch. Twice-daily topical treatments were performed with both agents alone and combined with and without fluoride: compound 1771 (2.6 µg/mL), myricetin (500 µg/mL), 1771 + myricetin, fluoride (250 ppm), 1771 + fluoride, myricetin + fluoride, 1771 + myricetin + fluoride, and vehicle. Biofilms were evaluated via microbiological, biochemical, imaging, and gene expression methods. Compound 1771 alone yielded less viable counts, biomass, exopolysaccharides, and extracellular LTA. Moreover, the combination 1771 + myricetin + fluoride decreased three logs of bacterium counts, 60% biomass, >74% exopolysaccharides, and 20% LTA. The effect of treatments on extracellular DNA was not pronounced. The combination strategy affected the size of microcolonies and exopolysaccharides distribution and inhibited the expression of genes linked to insoluble exopolysaccharides synthesis. Therefore, compound 1771 prevented the accumulation of S. mutans biofilm; however, the effect was more pronounced when it was associated with fluoride and myricetin.

The diversity of chemical compounds of bilih fish body (Mystacoleucus padangensis) originating from Lake Toba and Lake Singkarak, Sumatra, Indonesia

Razak A. 2018. The diversity of chemical compounds of bilih fish body (Mystacoleucus padangensis Bleeker) originating fromLake Toba and Lake Singkarak, Sumatra, Indonesia. Biodiversitas 19: 1552-1557. Bilih fish (Mystacoleucus padangensis) is anendemic fish in Lake Singkarak, West Sumatra. Bilih fish in Lake Singkarak experiencing pressure due to human activities that destroythe habitat of this fish in Lake Singkarak. The improvement of bilih fish habitat conducted by the government by introducing bilih fishto Lake Toba for bilih fish preservation. The purpose of this study is to describe the diversity of chemical compounds and their relationto several ecological factors that influence bilih fish in Lake Toba and Lake Singkarak. The research method is survey method. Bilih fishtaken at three to four points on both Lakes. The distance between sample points is 8000 m. The result of this research is to find themorphology of bilih fish from Lake Toba bigger than bilih Lake Singkarak fish. The bilih fish Fins of Lake Toba have a 52.08% CaOcompound (per 100 ppm sample), the fins of Lake Singkarak have a 53% CaO compound higher than Lake Toba, 51%. The content ofBilih Lake Toba fish muscle has P2O5 compounds 34,48% higher than Lake Singkarak with P2O5 34.58% higher, Bilih Danau Toba fishbone has CaO 57.66%, from Lake Singkarak 60,83%. Bilih Lake Toba has 97.32% Fluoride compound, higher than Lake Singkarak98.43%. The ecological conditions in Lake Toba are relatively similar to the condition of the waters in Lake Singkarak.

Synthesis, structure and reactivity of a terminal magnesium fluoride compound, [TpBut,Me]MgF: hydrogen bonding, halogen bonding and C–F bond formation

The terminal magnesium fluoride compound, [TpBut,Me]MgF, serves as a hydrogen bond and halogen bond acceptor for indole and C6F5I, and also reacts with Ph3CCl to form a C–F bond.

Adverse effects of fluoride towards thyroid hormone metabolism

An easily ionized fluoride compound like Sodium Fluoride (NaF) has been used thus far as a dental caries prevention substance. However, fluoride ions also have a negative effect because it is very toxic. Several types of research on the effect of fluoride on guinea pigs and human beings indicate the presence synthesis obstruction of T3 and T4 that causes declined production, known as hypothyroidism. Hypothyroidism condition may obstruct tissue growth process and metabolism so as to impact various body organ systems. Preventive efforts against hypothyroidism caused by fluoride include avoiding diffusible fluoride compound intake, like NaF, in a long run systemic use, whereas efforts to overcome fluoride intoxication include consuming food that is rich in calcium, vitamin D, and antioxidant.