Dos Santos Morais Raphael, Louvet Nicolas, Borges Frederic, Dumas Dominique, Cvetkovska-Ben Mohamed Loubiana, Barrau Sarah, Scher Joël, Gaiani Claire, Burgain Jennifer
LIBio, Université de Lorraine, F-54000 Nancy, France.
CNRS, LEMTA, Université de Lorraine, F-54000 Nancy, France.
Foods. 2021 May 1;10(5):991. doi: 10.3390/foods10050991.
Lactic acid bacteria (LAB) have been studied for several decades to understand and determine their mechanism and interaction within the matrix into which they are introduced. This study aimed to determine the spatial distribution of GG (LGG) in a dairy matrix and to decipher its behaviour towards milk components, especially fat globules. Two strains of this widely studied bacterium with expected probiotic effects were used: LGG WT with pili on the cell surface and its pili-depleted mutant-LGG Δ-in order to determine the involvement of these filamentous proteins. In this work, it was shown that LGG Δ was able to limit creaming with a greater impact than the wild-type counterpart. Moreover, confocal imaging evidenced a preferential microbial distribution as aggregates for LGG WT, while the pili-depleted strain tended to be homogenously distributed and found as individual chains. The observed differences in creaming are attributed to the indirect implication of SpaCBA pili. Indeed, the bacteria-to-bacteria interaction surpassed the bacteria-to-matrix interaction, reducing the bacterial surface exposed to raw milk. Conversely, LGG Δ may form a physical barrier responsible for preventing milk fat globules from rising to the surface.
几十年来，人们一直在研究乳酸菌（LAB），以了解并确定它们在引入的基质中的作用机制和相互作用。本研究旨在确定鼠李糖乳杆菌GG株（LGG）在乳制品基质中的空间分布，并解读其与乳成分，尤其是脂肪球的相互作用。使用了两株这种经过广泛研究且具有预期益生菌效果的细菌：细胞表面有菌毛的野生型LGG和菌毛缺失突变体LGGΔ，以确定这些丝状蛋白的作用。在这项研究中，结果表明LGGΔ比野生型更能有效抑制乳脂肪上浮。此外，共聚焦成像显示，野生型LGG以聚集体形式呈现出优先的微生物分布，而菌毛缺失菌株则倾向于均匀分布并以单链形式存在。观察到的乳脂肪上浮差异归因于SpaCBA菌毛的间接作用。事实上，细菌与细菌之间的相互作用超过了细菌与基质之间的相互作用，减少了暴露于原料乳的细菌表面积。相反，LGGΔ可能形成了一个物理屏障，负责阻止乳脂肪球上浮到表面。
