Problotics down-regulate flaA σ28 promoter in Campylobacter jejuni
Problotics down-regulate flaA σ28 promoter in Campylobacter jejuni
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DOI：
10.4315/0362-028x-68.11.2295
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发表时间：
2005-11-01
影响因子：
2
通讯作者：
Griffiths, MW
中科院分区：
文献类型：
--
作者：
Ding, W;Wang, HF;Griffiths, MW
乳酸杆菌和双歧杆菌是人类和动物胃肠道微生物群落的重要成员，被认为对人类健康具有积极影响。因此，人们对使用这些微生物作为益生菌掺入发酵乳制品或片剂的兴趣越来越大。然而，支持其健康益处的令人信服的科学数据很少。使用flaA sigma（28）启动子和质粒pRYluxCDABE上携带的无启动子luxCDABE盒之间的融合来评估由10种益生菌（5种双歧杆菌属菌株和5种乳杆菌属菌株）发酵的乳的无细胞提取物对空肠弯曲杆菌的flaA基因表达的影响，这导致菌株具有与flaA sigma（28）启动子活性相关的可定量发光。所有测试的益生菌菌株发酵的牛奶的无细胞提取物抑制了C。空肠和下调flaA sigma（28）启动子活性。两种非益生乳酸菌菌株，乳酸乳球菌和嗜热链球菌，抑制作用较小。
Lactobacilli and bifidobacteria are important members of the gastrointestinal microflora of humans and animals and are thought to have positive effects on human health. Therefore, there is an increasing interest in using these microorganisms as probiotics to be incorporated into either fermented dairy products or tablets. However, convincing scientific data that support claims of their health benefits are scarce. The effect of cell-free extracts of milk fermented by 10 probiotic bacteria (five Bifidobacterium strains and five Lactobacillus strains) on the expression of the flaA gene of Campylobacter jejuni was assessed using a fusion between the flaA sigma(28) promoter and a promoterless luxCDABE cassette carried on the plasmid pRYluxCDABE, which resulted in strains with quantifiable luminescence linked to flaA sigma(28) promoter activity. Cell-free extracts of milk fermented by all of the tested probiotic strains inhibited the growth of the C. jejuni and down-regulated flaA sigma(28) promoter activity. Two nonprobiotic lactic acid bacterial strains, Lactococcus lactis and Streptococcus thermophilus, were less inhibitory.