通过常规乳酸菌分离技术结合形态观察、生理生化试验,以及16S r DNA同源性分析等方法,从臭豆腐发酵卤水中分离获得7株戊糖片球菌分离株,并通过随机扩增多态性DNA技术构建了不同菌株的特征指纹图谱;以Caco-2细胞和固定化肠黏液蛋白质作为体外模型,研究了菌株的粘附能力,并探讨了菌株粘附能力与基因型以及表面疏水性、自凝聚能力等表型特征的相关性。结果显示,发酵卤水中的戊糖片球菌存在高度分子多样性,7个分离株中存在6种不同的指纹图谱模式,其中A5型菌株(F28-8和Y27-4)对Caco-2细胞和肠黏液蛋白质的粘附性最强,并显示了高度的疏水性(﹥90%)和较强的自凝聚能力(﹥25%)。相关性分析表明,戊糖片球菌表面疏水率和自凝聚率与Caco-2细胞粘附率测定结果呈显著正相关(r=0.900和0.792,P﹤0.05),但是与肠黏液蛋白质粘附率测定结果相关性不显著(r=0.426和0.700,P﹥0.05)。研究成果为建立高粘附性戊糖片球菌快速筛选方法及其体内定植和分布研究提供了依据。
Seven strains of Pediococcus pentosaceus were isolated and identified from the fermented stinky tofu brine using methods of conventional bacteria isolation combined with physiological and biochemical test and 16 S r DNA sequencing identification. The specific fingerprint for each strain was developed by the random amplified polymorphic DNA(RAPD) technique. The adhesive ability of the strain and the correlation of phenotypic characteristics of strain adhesion and genotype,surface hydrophobicity,and aggregation ability were studied using Caco-2 cell and intestinal mucus protein as in vitro model. Results showed that six different fingerprint patterns were found in the seven Pediococcus pentosaceus strains,among them,the A5 subtype of strains(F28-8 and Y27-4) showed the strongest adhesion to the Caco-2 cells and intestinal mucus. Furthermore,these two strains also exhibited highly hydrophobic(the hydrophobicity rate 90%) and higher aggregation ability(the aggregation rate at 2 h 5%). Correlation analysis results showed that the surface hydrophobicity and aggregation ability of Pediococcus pentosaceus were positively related to the adhesive ability to the Caco-2 cell significantly(r=0.900 and 0.792,P0.05),but they were not significantly correlated to the adhesive ability to the intestinal mucus(r = 0.426 and 0.700,P0.05). The results of this study provide the basis for establishing techniques of rapid screening highly adhesive Pediococcus pentosaceus strains and their colonization and distribution in vivo.