Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia.
Appl Environ Microbiol. 2012 Nov;78(22):7993-8000. doi: 10.1128/AEM.02141-12. Epub 2012 Sep 7.
Adhesion of bacteria to mucosal surfaces and epithelial cells is one of the key features for the selection of probiotics. In this study, we assessed the adhesion property of Lactococcus lactis subsp. lactis BGKP1 based on its strong autoaggregation phenotype and the presence of the mucin binding protein (MbpL). Genes involved in aggregation (aggL) and possible interaction with mucin (mbpL), present on the same plasmid pKP1, were previously separately cloned in the plasmid pAZIL. In vivo and in vitro experiments revealed potentially different physiological roles of these two proteins in the process of adherence to the intestine during the passage of the strain through the gastrointestinal tract. We correlated the in vitro and in vivo aggregation of the BGKP1-20 carrying plasmid with aggL to binding to the colonic mucus through nonspecific hydrophobic interactions. The expression of AggL on the bacterial cell surface significantly increased the hydrophobicity of the strain. On the other hand, the presence of AggL in the strain reduced its ability to adhere to the ileum. Moreover, MbpL protein showed an affinity to bind gastric type mucin proteins such as MUC5AC. This protein did not contribute to the binding of the strain to the ileal or colonic part of the intestine. Different potential functions of lactococcal AggL and MbpL proteins in the process of adhesion to the gastrointestinal tract are proposed.
细菌对黏膜表面和上皮细胞的黏附是益生菌选择的关键特征之一。在本研究中，我们根据乳球菌亚种 lactis BGKP1 的强自聚集表型和黏蛋白结合蛋白（MbpL）的存在来评估其黏附特性。先前已分别在质粒 pAZIL 中克隆了与聚集相关的基因（aggL）和可能与黏蛋白相互作用的基因（mbpL），它们位于同一质粒 pKP1 上。体内和体外实验揭示了这两种蛋白在该菌株通过胃肠道过程中黏附到肠道时可能具有不同的生理作用。我们将携带质粒 BGKP1-20 的体外和体内聚集与 aggL 与通过非特异性疏水相互作用与结肠黏液的结合相关联。AggL 在细菌细胞表面的表达显著增加了该菌株的疏水性。另一方面，菌株中 AggL 的存在降低了其黏附到回肠的能力。此外，MbpL 蛋白显示出与胃型黏蛋白蛋白（如 MUC5AC）结合的亲和力。该蛋白不参与该菌株与回肠或结肠部分肠道的结合。提出了乳球菌 AggL 和 MbpL 蛋白在黏附到胃肠道过程中的不同潜在功能。
