共查询到19条相似文献,搜索用时 156 毫秒
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乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制. 相似文献
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乳酸杆菌是人和动物肠道中重要的益生菌。益生菌进入肠道后,能够黏附定植并形成黏膜生物屏障,帮助肠道抵御各种致病菌的感染,维持肠道的正常功能。乳酸杆菌的黏附是由其表面蛋白、脂磷壁酸和胞外多糖等黏附素与宿主细胞表面的受体相结合的过程。为深入研究黏附机制,本文主要对乳酸杆菌黏附肠道上皮的黏附素和受体等方面进行综述。 相似文献
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肠道不仅是消化吸收的重要场所,也是生物体最大的免疫器官.肠道黏膜面积庞大,它的结构和功能构成了强大的黏膜免疫系统,加之在肠道中生存着大量的微生物菌群,致使外源细菌和病毒很难突破这道防线而对生物体产生危害,所以肠黏膜屏障结构的完整性对机体健康至关重要.肠内细菌移位、菌群紊乱和失调、肠黏膜屏障功能遭到破坏及局部免疫功能下降等极易引发肠源性感染.益生菌能降低肠道pH、减少细菌移位、阻止细菌黏附、防止肠黏膜屏障功能的破坏及增强局部免疫功能,预防和治疗肠源性感染.可见,肠内益生菌所形成的肠黏膜生物屏障在防止致病菌和内毒素经肠道入侵中发挥着重要的作用.现将其如何发挥屏障作用并与肠黏膜机械和免疫屏障协同配合进行探讨. 相似文献
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Differential regulation of porcine beta-defensins 1 and 2 upon Salmonella infection in the intestinal epithelial cell line IPI-2I 总被引:3,自引:0,他引:3
Veldhuizen EJ Hendriks HG Hogenkamp A van Dijk A Gaastra W Tooten PC Haagsman HP 《Veterinary immunology and immunopathology》2006,114(1-2):94-102
Intestinal epithelial cells represent the first line of defence against pathogenic bacteria in the lumen of the gut. Besides acting as a physical barrier, epithelial cells orchestrate the immune response through the production of several innate immune mediator molecules including beta-defensins. Here, we establish the porcine intestinal cell line IPI-2I as a new model system to test the regulation of porcine beta-defensins 1 and 2. Gene expression of both defensins was highly upregulated by foetal calf serum components in normal growth medium. In serum-free medium, baseline expression remained low, but pBD-2 gene expression was increased 10-fold upon infection with Salmonella Typhimurium. Arcobacter cryaerophilus and Salmonella Enteritidis, pathogenic bacteria with comparable adhesion and invasion characteristics, failed to increase pBD-2 mRNA levels. Heat killed or colistin-treated Salmonella Typhimurium had no effect, showing that the upregulation of pBD-2 was dependent on the viability of the Salmonella Typhimurium. Gene expression of pBD-1 was regulated differently since an increase in pBD-1 mRNA was observed by Salmonella Enteritidis infection. We conclude that the IPI-2I cells can serve as a new model to study porcine beta-defensin regulation and that pBD-1 and pBD-2 are differentially regulated in this cell line. 相似文献
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寻找抗生素替代品是养殖业面临的一大课题。片球菌(Pediococcus)是饲料添加目录中允许的益生菌之一,它是一种革兰氏阳性乳酸菌。大量研究表明,片球菌在食品、医疗和养殖行业中有着巨大的应用价值,它们在宿主肠道黏膜细胞表面具有的良好的定植能力,减少了其他细菌的黏附。同时,片球菌能够产生包括片球菌素、有机酸和过氧化氢在内的许多抗菌物质,因而在抑制病原菌生长、改善肠道微生物群落结构、刺激宿主免疫、促进养殖动物生产健康并提升动物生长性能等方面表现出良好的益生性能,但是相比较其他益生菌而言其关注程度不高。作者总结了片球菌产生抑菌物质的种类及其抑菌机制,介绍了片球菌的黏附和免疫调控作用方式,以及片球菌在猪和鸡等畜禽养殖动物生产上的应用,旨在为其在动物生产中的合理应用提供理论参考。片球菌具有广谱、稳定的抑菌效果,丰富的益生性能,它们有利于畜禽动物健康生长,预防病原菌感染,减少疾病发生,因此值得加大推广和应用的力度。 相似文献
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Finding antibiotic alternatives is a major issue in the breeding industry.Pediococcus, a kind of Gram-positive lactic acid bacteria,is one of the probiotics allowed in the feed addition catalogue.A large number of studies have shown that Pediococcus has great application value in the food,medical and breeding industries.Their good colonization ability on the surface of the host intestinal mucosal cells reduces the adhesion of other bacteria.Meanwhile,Pediococcus is able to produce many antibacterial substances including pediocin,organic acids and hydrogen peroxide.Therefore,it's showing their good probiotic performance in inhibiting the growth of pathogenic bacteria,improving the intestinal microbial community structure,stimulating the host's immunity,promoting the health of farmed animals,and improving animal growth performance,However,compared with other probiotics,its degree of attention is not high.This article summarizes the types of bacteriostatic substances produced by Pediococcus and their bacteriostatic mechanisms,introduces Pediococcus's adhesion and immune regulation,and the application of Pediococcus in the production of animals such as pigs and chickens.The aim was to provide a theoretical reference for Pediococcus's reasonable application in animal production.The results discussed in this article indicated that Pediococcus had broad-spectrum,stable bacteriostatic effects and rich probiotic properties.It's beneficial to the healthy growth of livestock and poultry,prevents pathogenic bacterial infections,and reduces the incidence of diseases.Therefore,Pediococcus is worth increasing its promotion and application. 相似文献
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主要介绍了细菌生物膜的概念及其形成过程、细菌群体感应(QS)的概念以及革兰阴性菌的AHL-LuxI/LuxR型QS系统、革兰阳性菌的QS系统、LuxS/AI-2介导的种间QS系统、AI-3/肾上腺素/去甲肾上腺素信息系统4种QS系统的调节机制。就QS系统在细菌中发挥的作用以及对生物膜的调控进行初步阐述,以期为乳酸菌的开发利用和致病菌耐药性的研究提供参考。 相似文献
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