Jiangsu Marine Resources Development Research Institute, Huaihai Institute of Technology, Lianyungang 222005, China.
Key Laboratory of Marine Biology, Nanjing Agricultural University, Nanjing 210000, China.
Mar Drugs. 2018 Feb 7;16(2):51. doi: 10.3390/md16020051.
This study evaluated the ability of a dextranase from a marine bacterium sp. (Cadex) to impede formation of biofilms, a primary pathogen of dental caries, one of the most common human infectious diseases. Cadex was purified 29.6-fold and had a specific activity of 2309 U/mg protein and molecular weight of 75 kDa. Cadex showed maximum activity at pH 8.0 and 40 °C and was stable at temperatures under 30 °C and at pH ranging from 5.0 to 11.0. A metal ion and chemical dependency study showed that Mn and Sr exerted positive effects on Cadex, whereas Cu, Fe, Zn, Cd, Ni, and Co functioned as inhibitors. Several teeth rinsing product reagents, including carboxybenzene, ethanol, sodium fluoride, and xylitol were found to have no effects on Cadex activity. A substrate specificity study showed that Cadex specifically cleaved the α-1,6 glycosidic bond. Thin layer chromatogram and high-performance liquid chromatography indicated that the main hydrolysis products were isomaltoogligosaccharides. Crystal violet staining and scanning electron microscopy showed that Cadex impeded the formation of biofilm to some extent. In conclusion, Cadex from a marine bacterium was shown to be an alkaline and cold-adapted endo-type dextranase suitable for development of a novel marine agent for the treatment of dental caries.
本研究评估了一种海洋细菌 sp.（Cadex）来源的葡聚糖酶抑制龋齿主要病原体——生物膜形成的能力，龋齿是最常见的人类传染病之一。Cadex 经纯化后得到 29.6 倍的富集，比活为 2309 U/mg 蛋白，分子量为 75 kDa。Cadex 在 pH8.0 和 40°C 时表现出最大活性，在 30°C 以下温度和 pH5.0-11.0 范围内稳定。金属离子和化学依赖性研究表明，Mn 和 Sr 对 Cadex 有积极影响，而 Cu、Fe、Zn、Cd、Ni 和 Co 则起抑制作用。几种牙齿冲洗产品试剂，包括苯甲酸、乙醇、氟化钠和木糖醇，对 Cadex 活性没有影响。底物特异性研究表明，Cadex 特异性切割α-1,6 糖苷键。薄层色谱和高效液相色谱表明，主要水解产物是异麦芽糖寡糖。结晶紫染色和扫描电子显微镜观察表明，Cadex 在一定程度上抑制了生物膜的形成。综上所述，海洋细菌来源的 Cadex 是一种碱性、耐冷的内切型葡聚糖酶，适合开发用于治疗龋齿的新型海洋药物。
