富硒长双歧杆菌DD98菌株的黏附特性及黏附机制初步研究

Adhesion Ability of Selenium-enriched Bifidobacterium longum DD98 to Caco-2 Cell and Preliminary Study on Its Mechanism

利用Caco-2细胞作为体外黏附模型,通过细菌黏附率评价一株新的长双歧杆菌菌株DD98(Bifidobacterium longum DD98,DD98)富硒前后的黏附能力,测定细菌自动聚集能力与表面疏水性,采用荧光定量PCR技术检测细菌表面Tuf蛋白mRNA表达量差异。结果表明,与DD98相比,富硒DD98(Selenium-enriched Bifidobacterium longum DD98,Se-DD98)黏附于Caco-2细胞的数量从(39.12±17.57)CFU/100cells上升到(581.17±62.79)CFU/100cells,Se-DD98对Caco-2细胞的黏附能力极显著升高(p<0.01)。相比DD98,Se-DD98自动聚集能力略有上升,且其表面疏水性从5.12%±0.16%上升到20.25%±2.14%,极显著性升高(p<0.01);荧光定量PCR结果表明,与Caco-2细胞共孵育2h后,Se-DD98菌体表面Tuf黏附蛋白表达显著上调(p<0.05)。表明DD98经富硒培养后,黏附能力显著提升,其黏附能力的增强可能与细菌表面Tuf黏附蛋白的改变有关。

In order to study whether there was a difference in the adhesion ability of a new Bifidobacterium strain DD98 ( Bifidobacterium longum DD98,DD98) before and after selenium enrichment,bacterial adhesion rate was evaluated by in vitro adhesion model of Caco-2 cells,the auto-aggregation ability and surface hydrophobicity of the bacteria were also determined, Tuf mRNA,as the quantitative expression of bacterial surface protein was detected by real-time fluorescent quantitative PCR. The results showed that selenium- enriched Bifidobacterium longum DD98 ( Se- DD98) presented extremely higher adhesive ability to Caco-2 cells than DD98( p < 0.01).The average number of DD98 bacteria adhering to Caco-2 cells was( 39.12 ± 17.57) CFU/100 cells,while the number of Se-DD98 was( 581.17 ± 62.79) CFU/100 cells.Compared with the DD98,the auto -aggregation ability of Se- DD98 increased slightly,and the surface hydrophobicity increased significantly from 5.12%± 0.16% to 20.25%± 2.14%( p < 0.01).The results of real- time PCR showed that the expression of Tuf protein mRNA on Se-DD98 cells significantly up-regulated after 2 h incubation with Caco-2 cells( p < 0.05).It was indicated that the adhesion ability of DD98 after selenium-enriched culture was significantly improved,and the enhancement of adhesion might be related to the change of Tuf protein.