益生菌预防与治疗艰难梭菌腹泻的研究进展

近二十年来随着抗生素的广泛应用,艰难梭菌引起腹泻(CDAC)的发病率和死亡率都在不断地提高。当病人服用抗生素后肠道菌群遭到了严重破坏,不能有效地抑制艰难梭菌在肠道的生长和定植,从而引起腹泻。目前药物治疗艰难梭菌腹泻常用的药物为甲硝唑和万古霉素,但由于长期药物治疗会引起耐药性,而且经常发生复发情况,益生菌通过增强肠道菌群治疗或者配合药物治疗成为一种经济有效的方法。目前公认的益生菌抑制艰难梭菌腹泻的机理有:抑制艰难梭菌生长;抑制艰难梭菌粘附;刺激免疫系统。本文介绍了艰难梭菌腹泻的发病机理和流行病学研究以及益生菌配合药物使用在治疗艰难梭菌腹泻中的作用,重点介绍了益生菌抑制艰难梭菌腹泻的作用途径和机理。      

浅谈肠道益生菌在食品中的安全性问题

近年来益生菌食品发展迅速,其产品类型及品种日益丰富,但目前其产业还处于发展阶段。益生菌的安全性和功能性评价体系不够完善,质量检验方法有待改进。本文综述了食品中肠道益生菌的分类、鉴定,益生菌的代谢产物,储存条件,益生菌剂量水平与使用时间,益生菌对抗生素的耐受性及感染能力及对人体安全性影响,且举例说明了目前市场上的益生菌产品可能带来的问题,以期为食品中肠道益生菌的研究、检验、监测提供理论参考。     

肠道益生菌功能特性研究进展

综述了肠道益生菌的功能特性并对益生菌在食品中的应用现状做了简要概述。     

益生菌复合配方对小鼠肠道功能的影响

目的:推动益生菌复合配方工业化生产。方法:建立小鼠便秘、肠黏膜损伤、腹泻模型,考察对照组、模型组和干预组小鼠的小肠墨汁推进率、排便情况、肠黏膜组织切片,并结合肠黏膜损伤评分和腹泻评分进行综合评价。结果:与模型组相比,中、高浓度益生菌复合配方能显著提高便秘模型小鼠的黑便粒数、重量和小肠墨汁推进率,同时显著降低肠黏膜损伤模型小鼠的肠黏膜损伤评分,减轻组织病理损伤。对于腹泻模型小鼠而言,低、中、高浓度益生菌复合配方干预均可显著降低小鼠肠黏膜损伤等级。结论:中、高浓度的益生菌复合配方均具有改善小鼠便秘,减轻肠黏膜损伤,缓解腹泻症状的作用,其中高浓度效果更佳。     

人体肠道益生菌的作用及其应用

益生菌在人体肠道中定殖,并通过一系列代谢活动调节肠道微生态平衡,增强人体消化、免疫等功能.为了正确认识和应用益生菌从而达到增强人体健康的的益生作用,综述了近年来对益生菌功能的研究情况,及其在临床和食品上的主要应用,并对益生菌未来的研究方向提出了个人的观点和展望.     

牛初乳中IGF-I提取物对肠黏膜修复作用的研究

目的:研究牛初乳中胰岛素生长因子-I（IGF-I）对大鼠受损肠黏膜的修复作用。方法:应用氨甲喋呤制备大鼠小肠炎模型,实验设正常对照组,MTX模型对照组（20μg/kg）,牛初乳IGF-I提取物修复组（75μg/kg）,IGF-I修复组（75μg/kg）。后2组每天灌胃给药1次,给药时间从造模后第2d开始至实验结束,共5d。第6d检测大鼠血浆二氨氧化酶（DAO）活性、血浆D-乳酸水平,光镜下观察小肠组织病理形态学改变。结果:与对照组相比,模型组大鼠血浆DAO活性和血浆D-乳酸水平明显升高（P<0.05）,小肠损伤程度明显高于对照组（P<0.05）,牛初乳中IGF-I提取物组和IGF-I组可降低血浆DAO活性及D-乳酸水平（P<0.05）,减轻小肠损伤程度（P<0.05）。结论:牛初乳中IGF-I提取物能够明显减轻大鼠肠黏膜的损伤,同时可减轻炎细胞的浸润,对实验性大鼠的小肠炎具有修复作用。      

益生菌与益生元对人体肠道正常菌群的调节作用

为了解益生菌与益生元对人体肠道菌群的调节作用，选择符合试验要求的成年志愿者，分别食用益生菌和益生元，其中益生菌组150人，益生元组200人，男女各半。结果表明：益生菌与益生元均可增加人体肠道内的双歧杆菌和乳杆菌：均可使肠道内肠杆菌数量下降。但益生菌组双歧杆菌和乳杆菌增加的数量及肠杆菌和拟杆菌降低的数量均高于益生元组，说明在该试验条件下，益生菌组的效果要好于益生元组。     

模拟肠道环境下肠道益生菌对三种重金属离子的富集作用的研究

本研究考察了嗜酸乳杆菌、嗜热链球菌、双歧杆菌三种肠道益生菌在模拟肠道环境条件下生长情况及对Cr6+、Cd2+、Pb2+的吸附特性。结果显示:嗜酸乳杆菌对Cr6+有较强的吸附和富集作用,最大吸附率为70%,吸附量为0.0021 mg/g;嗜热链球菌对Cr6+、Cd2+均有较强的吸附和富集作用,最大吸附率分别为50%和62%,吸附量分别为0.0015 mg/g和0.1057 mg/g;双歧杆菌对Cr6+、Cd2+均有较强的吸附和富集作用,最大吸附率分别为66.6%和69.9%,吸附量分别为0.0019 mg/g和0.1298 mg/g;三种肠道益生菌在模拟肠道环境下对Pb2+均无明显吸附作用。      

益生菌抗癌功能及作用机制研究进展

益生菌在许多方面发挥了健康作用,然而与益生菌整肠功能、免疫调节功能等研究比较深入的益生功能相比较,其抗癌机制不太明确,抗癌功能颇受争议。本文综述动物实验和流行病学调查结果,支持益生菌具有抗癌功能的观点。目前对益生菌抗癌机制了解不多,其作用可能不是由单因素的机制来实现的,而是由包括直接作用和间接作用几种因素在内综合作用的结果。直接作用包括菌体本身或其活性代谢产物对致突变物的结合或降解作用,间接作用就是通过调节肠道菌群及其代谢酶活性、调节机体免疫功能、调节宿主相关的酶活力来起到抗癌作用。      

A synbiotic marine oligosaccharide microcapsules for enhancing Bifidobacterium longum survivability and regulatory on intestinal probiotics

A novel synbiotic multiparticulate microparticle containing alginate oligosaccharide (AOS), chitosan oligosaccharide (COS) and Bifidobacterium longum CICC 6259 was produced in the current study to expand the synbiotic industrial applications. The influences of these treatments on encapsulation yield, size, morphology, protective effect and stability of microcapsules and on mice gut microbiome were studied in vitro and in vivo. In vitro experiments detected no significant difference (P > 0.05) in encapsulation yield with different types of microcapsules. However, the microcapsule diameter of marine oligosaccharide was approximately 60 μm greater, and these microcapsules increased the number of surviving cells by more than 3 log cfu/g after treatment with simulated gastrointestinal juices, compared to basic alginate microcapsules. In vivo, these microcapsules significantly increased the content of Bifidobacterium and Lactobacillus and reduced the content of Enterococcus and Escherichia in mice gut microbiome. Marine oligosaccharide probiotic microcapsules are promising as a novel functional food ingredient.     

Investigation of the possible use of probiotics in ice cream manufacture

This study attempted to investigate the possibility of using some types of probiotic bacteria in the production of ice cream and was aimed at making a contribution to the manufacture of new functional foods. For this purpose, different cream levels (5% and 10%) and different strains of probiotic bacteria ( Lactobacillus acidophilus , Bifidobacterium bifidum and both) were used in ice cream production to determine their effects on the quality of the ice creams in each group. During storage of 1, 15, 30, 45, 60, 75 and 90 days, L. acidophilus , B. bifidum counts and sensory analyses were performed. The results obtained at the end of storage demonstrated that the counts of L. acidophilus and B. bifidum continued to decrease during the storage but all types of ice cream sample seemed to preserve their probiotic property even after 90 days. Higher counts of probiotic bacteria were observed in the samples with L. acidophilus , B. bifidum , and L. acidophilus and B. bifidum in double-cultured samples respectively. In general, it appeared that the ice cream samples with 5% cream content were found to be more delectable. All ice cream samples have shown good results in preserving their probiotical properties for more than 3 months. Although sensory scores of probiotic ice cream samples reduced during this time, they rated as 'tasty' throughout the storage.     

谷朊粉水解物对MTX诱导大鼠小肠炎症的修复作用

通过MTX(氨甲蝶呤)诱导的大鼠小肠炎模型,探讨富含谷氨酰胺的谷朊粉胰蛋白酶水解物对小肠粘膜损伤的修复作用。结果表明:水解物能显著提高小肠炎大鼠的小肠粘膜重量、绒毛高度、隐窝深度以及小肠粘膜的蛋白和DNA含量,同时降低血浆中二胺氧化酶水平和提高小肠粘膜谷胱甘肽含量。表明谷朊粉胰蛋白酶水解物可以有效地缓解大鼠小肠炎的肠粘膜损伤症状。     

Exopolysaccharides produced by probiotic strains modify the adhesion of probiotics and enteropathogens to human intestinal mucus

Exopolysaccharides (EPSs) are exocellular polymers present in the surface of many bacteria, including Lactobacillus and Bifidobacterium. The genome sequence of several strains revealed the presence of EPS-encoding genes. However, the physiological role that EPSs play in the bacterial ecology still remains uncertain. In this study, we have assessed the effect of EPSs produced by Lactobacillus rhamnosus GG, Bifidobacterium longum NB667, and Bifidobacterium animalis IPLA-R1 on the adhesion of probiotic and enteropathogen strains to human intestinal mucus. The EPS fraction GG had no significant effect on the adhesion of L. rhamnosus GG and B. animalis IPLA-R1. However, the EPS fractions NB667 and IPLA-R1 significantly reduced the adherence of both probiotic strains. In contrast, the three EPS fractions increased the adhesion of Enterobacter sakazakii ATCC 29544 and Escherichia coli NCTC 8603. Higher adherence of Salmonella enterica serovar Typhimurium ATCC 29631 and Clostridium difficile ATCC 9689 was detected in the presence of the EPS fractions GG and NB667. In general, these effects were obtained at EPS concentrations of up to 5 mg/ml, and they were EPS dose dependent. The competitive exclusion of probiotics in the presence of EPS could suggest the involvement of these biopolymers in the adhesion to mucus. The increase in the adherence of enteropathogens could be explained if components of the pathogen surface are able to bind to specific EPSs and the bound EPSs are able to adhere to mucus. To the best of our knowledge, this is the first work reporting the effect of EPSs from probiotics on bacterial adhesion properties.     

Selection of Lactobacillus strains from fermented sausages for their potential use as probiotics

A rapid screening method was used to isolate potentially probiotic Lactobacillus strains from fermented sausages after enrichment in MRS broth at pH 2.5 followed by bile salt stressing (1% bile salts w/v). One hundred and fifty acid- and bile-resistant strains were selected, avoiding preliminary and time-consuming isolation steps. Strains were further characterized for survival at pH 2.5 for 3 h in phosphate-buffered saline and for growth in the presence of 0.3% bile salts with and without pre-exposure at low pH. Twenty-eight strains showed a survival >80% at pH 2.5 for 3 h; moreover, most of the strains were able to grow in the presence of 0.3% bile salts. Low pH and bile resistance was shown to be dependent on both the species, identified by phenotypic and molecular methods, and the strain tested. This is the first report on the direct selection of potentially probiotic lactobacilli from dry fermented sausages. Technologically interesting strains may be used in the future as probiotic starter cultures for novel fermented sausage manufacture.     

新疆喀什长寿老人肠道益生菌的分离鉴定及生物学特性研究

从新疆喀什长寿老人肠道中分离筛选出具有益生功能的乳酸菌,并对其进行体外降甘油三酯能力试验。结果表明,分离获得的41株乳酸菌中有14株菌的甘油三酯降解率均高于15%,其中株菌A2-1、A1-2、A3-1、A4-6、A4-1在pH为3.0的人工胃液中培养3 h的存活率较高,分别为63.22%,60.01%,58.94%,56.14%,50.29%;同时这5菌株在胆盐浓度为1,3,5g/L的MRS培养基中存活率较高,其中存活率最高的菌株为A1-2,存活率分别为46.61%,42.65%,16.32%;经16SrDNA鉴定,A1-2为植物乳杆菌(Lactobacillus plantarum),A2-1、A3-1、A4-6为屎肠球菌(Enterococcus faecium),A4-1为干酪乳杆菌(Lactobacillus paracasei)。     

Fermented milk supplemented with probiotics and prebiotics can effectively alter the intestinal microbiota and immunity of host animals

Fermented milk supplemented with 2 probiotic strains, Bifidobacterium lactis Bi-07 and Lactobacillus acidophilus NCFM, and a prebiotic, isomaltooligosaccharide, was orally administered to 100 healthy adults at 480g/d for 2 wk in a randomized controlled trial. The fecal bacterial compositions of these subjects were examined by culture before and after the intervention. The same fermented milk was also orally fed to BALB/c mice, and immune as well as fecal bacteria analyses were conducted using the same culturing methods. After the intervention, increases in fecal bifidobacteria and lactobacilli were observed among the subjects compared with the subjects in the control group. In contrast, after the intervention, fecal enterobacilli were significantly decreased in the test group compared with the control group. The same effects on the composition of the intestinal microbiota were observed in mice. Furthermore, the tested mice were found to have significantly increased delayed-type hypersensitivity, plaque-forming cells, and half-hemolysis values after the intervention with the fermented milk. In summary, the synbiotic fermented milk containing probiotics and a prebiotic may contribute to improve intestinal health and may have a positive effect on the humoral and cell-mediated immunity of host animals.     

Bioprotectives and probiotics for dry sausages

The microbial stability of dry sausages is determined by the combination and timing of different factors referred to as the hurdle-concept. However, the hurdles present in dry sausage are not sufficient to prevent the survival of Listeria monocytogenes or enterohemorrhagic Escherichia coli O157:H7. Recently bioprotective lactic acid bacteria, which in addition to the production of antimicrobial lactic acid, have been found to contribute to the safety of the dry sausage by producing antimicrobial peptide, i.e. bacteriocins and other low-molecular-mass compounds. Furthermore, the possibilities to use probotics in dry sausage manufacturing process has been addressed recently. As one possible mode of action for probiotics is the production of antimicrobial compounds, lactic acid bacteria may act as both probiotic and bioprotective culture as well as fermenting agent in meat product, such as dry sausage.     

Immunomodulating peptides for food allergy prevention and treatment

Among the most promising strategies currently assayed against IgE-mediated allergic diseases stands the possibility of using immunomodulating peptides to induce oral tolerance toward offending food allergens or even to prevent allergic sensitization. This review focuses on the beneficial effects of food derived immunomodulating peptides on food allergy, which can be directly exerted in the intestinal tract or once being absorbed through the intestinal epithelial barrier to interact with immune cells. Food peptides influence intestinal homeostasis by maintaining and reinforcing barrier function or affecting intestinal cell-signalling to nearby immune cells and mucus secretion. In addition, they can stimulate cells of the innate and adaptive immune system while supressing inflammatory responses. Peptides represent an attractive alternative to whole allergens to enhance the safety and efficacy of immunotherapy treatments. The conclusions drawn from curative and preventive experiments in murine models are promising, although there is a need for more pre-clinical studies to further explore the immunomodulating strategy and its mechanisms and for a deeper knowledge of the peptide sequence and structural requirements that determine the immunoregulatory function.     

防治幽门螺杆菌感染的益生菌研究进展

幽门螺杆菌(H.pylori)作为慢性胃炎、消化性溃疡甚至胃癌的主要致病因素,随着H.pylori耐药率的增加、长期不合理应用抗生素可引起胃肠功能紊乱及胃肠道菌群失调等不良反应。国内外学者对益生菌防治H.pylori感染进行大量的临床和体外研究,表明益生菌具有抗感染,还能调节机体的免疫机能,平衡胃肠道正常菌群,降低抗生素的副作用等多种生物学功能,因此益生菌的运用将对H.pylori相关疾病的防治具有重要的意义。本文对抗H.pylori的益生菌的研究进展做一综述。     

薄壁类零件变形的综合处理

为了防止薄壁类零件变形 ,分析了导致变形的各种因素 ,并针对易产生的问题 ,分别从工艺、金属切削、校直等方面提出了解决变形的措施 ;采取这些措施 ,使不同类型的薄壁类零件的精度、稳定性得到普遍提高。