Charteris W P, Kelly P M, Morelli L, Collins J K
SET Consultants Ltd, Douglas, Cork, Ireland.
J Appl Microbiol. 1998 May;84(5):759-68. doi: 10.1046/j.1365-2672.1998.00407.x.
An in vitro methodology which mimics in vivo human upper gastrointestinal transit was developed. The transit tolerance of potentially probiotic Lactobacillus and Bifidobacterium species was determined by exposing washed cell suspensions at 37 degrees C to a simulated gastric juice (pH 2.0), containing pepsin (0.3% w/v) and sodium chloride (0.5% w/v), and a simulated small intestinal juice (pH 8.0), containing pancreatin USP (1 g l-1) and sodium chloride (5 g l-1), and monitoring changes in total viable count periodically. The methodology was also employed to determine the effect of adding milk proteins (1 g l-1), hog gastric mucin (1 g l-1) and soyabean trypsinchymotrypsin inhibitor [SBTCI] (1 g l-1) on transit tolerance. The majority (14 of 15) of isolates lost > 90% viability during simulated gastric transit. Only one isolate, Lactobacillus fermentum KLD, was considered intrinsically resistant. The addition of milk proteins, singly and in combination, generally improved gastric transit tolerance. In this regard, two isolates, Lact. casei 212.3 and Bifidobacterium infantis 25962, exhibited 100% gastric transit tolerance in the presence of milk proteins. In general, the addition of hog gastric mucin did not influence simulated gastric transit tolerance of lactobacilli but tended to increase that of bifidobacteria. However, it increased that of Lact. casei 242 and Lact. salivarius 43338 but diminished that of B. bifidum 2715 and B. animalis Bo. Selected bile salts-resistant isolates were intrinsically tolerant to simulated small intestinal transit. Only Lact. casei F19 and B. adolescentis 15703T showed significant reduction in viability after 240 min. In general, the addition of milk proteins and SBTCI did not affect simulated small intestinal transit tolerance. However, they significantly improved the intrinsic resistance of Lact. casei F19 but diminished that of B. breve 15700T. It is concluded that, whereas the majority of bile salts-resistant lactobacilli and bifidobacteria may be intrinsically sensitive to gastric transit, they are intrinsically resistant to small intestinal transit. In addition, it is postulated that milk proteins and mucin may function as both buffering agents and inhibitors of digestive protease activity in vivo, thereby protecting ingested bacterial strains during upper gastrointestinal transit.
开发了一种模拟人体上消化道转运的体外方法。通过将洗涤后的细胞悬液在37℃下暴露于含有胃蛋白酶（0.3% w/v）和氯化钠（0.5% w/v）的模拟胃液（pH 2.0）以及含有胰蛋白酶USP（1 g l-1）和氯化钠（5 g l-1）的模拟小肠液（pH 8.0）中，并定期监测总活菌数的变化，来确定潜在益生菌乳酸杆菌和双歧杆菌属的转运耐受性。该方法还用于确定添加乳蛋白（1 g l-1）、猪胃粘蛋白（1 g l-1）和大豆胰蛋白酶-糜蛋白酶抑制剂[SBTCI]（1 g l-1）对转运耐受性的影响。在模拟胃转运过程中，大多数（15株中的14株）分离株的活力损失>90%。只有一株分离株，即发酵乳杆菌KLD，被认为具有内在抗性。单独或联合添加乳蛋白通常可提高胃转运耐受性。在这方面，两株分离株，干酪乳杆菌212.3和婴儿双歧杆菌25962，在有乳蛋白存在的情况下表现出100%的胃转运耐受性。一般来说，添加猪胃粘蛋白不会影响乳酸杆菌的模拟胃转运耐受性，但往往会增加双歧杆菌的耐受性。然而，它增加了干酪乳杆菌242和唾液乳杆菌43338的耐受性，但降低了两歧双歧杆菌2715和动物双歧杆菌Bo的耐受性。选定的耐胆盐分离株对模拟小肠转运具有内在耐受性。只有干酪乳杆菌F19和青春双歧杆菌15703T在240分钟后活力显著降低。一般来说，添加乳蛋白和SBTCI不会影响模拟小肠转运耐受性。然而，它们显著提高了干酪乳杆菌F19的内在抗性，但降低了短双歧杆菌15700T的内在抗性。得出的结论是，虽然大多数耐胆盐的乳酸杆菌和双歧杆菌可能对胃转运具有内在敏感性，但它们对小肠转运具有内在抗性。此外，据推测，乳蛋白和粘蛋白可能在体内起到缓冲剂和消化蛋白酶活性抑制剂的作用，从而在上消化道转运过程中保护摄入的细菌菌株。
