副干酪乳杆菌NCU622耐酸耐胆盐及其黏附性能

通过体外实验研究副干酪乳杆菌NCU622的耐酸、耐胆盐性能；采用体外细胞模型（人体结肠腺癌细胞系Caco-2细胞）测定副干酪乳杆菌NCU622的黏附性能，考察了菌体浓度、作用时间及生长阶段对其黏附性能的影响，并对该菌株进行细胞毒性检测。结果表明：副干酪乳杆菌NCU622在pH 2.5的MRS液体培养基中作用3 h，存活率为98.21%；在胆盐质量浓度为0.3、0.5 g/100 mL的MRS液体培养基中作用4 h，存活率分别为95.14%和85.07%。副干酪乳杆菌NCU622对Caco-2细胞的黏附能力较强，为（21.19±0.94）CFU/Caco-2细胞，且菌体浓度、作用时间及生长阶段对其黏附性能均有影响。副干酪乳杆菌NCU622与Caco-2单层细胞共培养24 h后，对其无裂解作用。这表明副干酪乳杆菌NCU622具有良好的耐酸耐胆盐能力及较强的黏附性能，且对Caco-2细胞无裂解作用，符合微生态制剂和乳酸菌发酵功能食品的菌种要求。

Acid,Bile Tolerance and Adhesion Properties of Lactobacillus paracasei NCU622

Lactobacillus paracasei NCU622 was examined for resistance to acid and bile, adhesion to Caco-2 cells, and
cytotoxicity against Caco-2 cells. Furthermore, the impacts of bacterial concentration, incubation time and growth stage
on the adhesion were also studied. It was found that L. paracasei NCU622 showed a survival rate of 98.21% after 3 h
incubation in MRS broth adjusted to pH 2.5. The survival rates of L. paracasei NCU622 were 95.14% and 85.07% after
4 h incubation in MRS broth supplemented with 0.3 and 0.5 g/100 mL oxgall, respectively. The adhesion ((21.19±0.94)
CFU/Caco-2 cell) of L. paracasei NCU622 was very excellent which was affected by the bacterial concentration, incubation
time and growth stage. Moreover, L. paracasei NCU622 did not cause Caco-2 cells lysis after 24 h co-culture. In summary,
L. paracasei NCU622 tolerated well acid and bile, expressed high adhesion to Caco-2 cells, and did not cause Caco-2 cells lysis.
These results demonstrate that L. paracasei NCU622 presents favorable strain-specific properties for its utilization as probiotics in
microecologics and fermented functional foods, and may have broad prospects for applications in fermented and functional foods.