应激状态下的变异链球菌差异蛋白组学

Differential proteomics of Streptococcus mutans under stress condition

当外界生存环境发生变化时,变异链球菌可在短时间内通过诱导或抑制某些蛋白质表达而改变自身蛋白质的表达谱,使其能够在极端环境中存活。在pH5.5和有氧环境下,变异链球菌的蛋白质表达变化迅速且复杂,或上调或下降。细菌胞外的高渗透压可使变异链球菌通过激活或灭活特异性的酶和转运蛋白以及改变基因表达谱来调整其生理机能,在高渗透压环境下培养,变异链球菌的蛋白质点或上调或下降。充足的营养对变异链球菌的生长非常重要,为适应营养缺乏的生存环境,变异链球菌的细胞大小和脂肪酸组成会发生改变,其总的蛋白质合成率也会下降。在环境温度变化的应激状态下,变异链球菌细胞内会产生变性或异常的蛋白质,所产生的热休克蛋白可使蛋白质肽链重新折叠,恢复蛋白质原来的构象及原有的功能,其蛋白质或上调或下调。在某些中草药提取物存在的情况下,变异链球菌的蛋白质表达明显下调。应用蛋白组学技术,可以发现在不同应激状态下变异链球菌的蛋白质表达图谱的改变,这可以揭示变异链球菌致龋的机制,从而为龋病的防治提供科学依据。

When external environment changes, Streptococcus mutans（S.mutans） can change its protein expression profile through induction or inhibition of some protein expressions to ensure survival in extreme environments. Under pH 5.5 and aerobic condition, the protein expression of S.mutans changes rapidly in a complicated manner by increasing or decreasing. The extracellular high osmotic pressure of bacteria can induce S.mutans to adjust its physiological function by activating or inactivating some special enzymes and transport proteins and changing the gene expression profile. When cultivated under high osmotic pressure, protein points of S.mutans may be increased or reduced. Adequate nutrition is very important for the growth of S.mutans. To adapt to lack of nutrition, cell size and composition of S.mutans fatty acid change with decrease in total synthesis rate of proteins. When environment temperature changes, the cells will produce denatured or abnormal proteins with increased or reduced expressions. The heat shock protein produced can induce protein peptides to refold; it can also restore the original conformation and function of proteins. Some Chinese herbal medicine extracts can significantly reduce the protein expression of S.mutans. With the application of proteomics techniques, changes in S.mutans protein expression pattern can be found under different stress states. These techniques reveal information on the mechanism of S.mutans to caries and provide a scientific basis for prevention and control of caries.