益生乳酸菌遗传稳定性研究进展

益生乳酸菌因为与人类健康息息相关而日益备受关注。时至今日,益生乳酸菌衍生制品已发展成为时尚养生领域的新宠儿。对于准备进入生产流通环节的益生乳酸菌,除需具有优异的益生特性,还应具有良好的稳定性。本文拟从遗传稳定性的研究方法出发,结合其国内外的研究进展作一综述,旨在为同行提供一些参考。     

乳酸菌在疾病防治和人体保健中的应用研究进展

肠道微生物在人体健康方面起着重要的作用,良好的肠道微生态环境是维持人体健康的重要因素,随着对肠道微生物越来越多的关注和研究,人们发现益生菌在肠道菌群和宿主健康之间有着复杂的关系。大量的研究发现,乳酸菌作为益生菌在人体肠道微生态平衡、疾病防治和保健中起着至关重要的作用。综述了乳酸菌对人体微生态环境的益生功能,并对乳酸菌和人体微生态环境之间的相互影响和关系,以及乳酸菌对一些常见人体疾病的预防和治疗作用的研究进展。     

10株乳酸菌黏附小鼠派伊尔结及免疫调节作用研究

目的探索乳酸菌黏附派伊尔结效率与其免疫调节作用的关系。方法利用荧光定量分析法测定10株乳酸菌黏附派伊尔结的能力,利用乳酸菌与派伊尔结组织块共培养测定乳酸菌调节派伊尔结细胞因子释放活性。选择诱导细胞因子谱相似、黏附派伊尔结性质不同的菌株进行动物实验,测定其对卵清蛋白（OVA）致敏小鼠粪便中分泌型免疫球蛋白A（sIgA）以及腹腔巨噬细胞吞噬活性的调节作用。结果10株乳酸菌黏附派伊尔结的性质具有菌株依赖性,其中L.rhamnosusGG、L.acidophilusFn037、L.plantarumFn008和L.caseiFn012黏附性依次降低,但诱导派伊尔结TNF-α、IL-10和IL-12释放的性质相同。这4株菌增强OVA致敏小鼠腹腔巨噬细胞吞噬活性和升高粪便sIgA的能力与其黏附性相关。结论乳酸菌黏附派伊尔结是决定其免疫调节活性的主要因素之一。     

降胆固醇乳酸菌的应用及其机理研究进展

乳酸菌除了能够改善肠道微生态环境促进人体健康外,有些乳酸菌还具有能降低人体血清胆固醇的特性。近年来许多研究都已证明某些乳杆菌、双歧杆菌及肠球菌等具有调节血脂代谢、降低人体血清胆固醇的能力。本文综述了降胆固醇乳酸菌的体外筛选模型及其降胆固醇的作用机理,以期为进一步开发相关产品提供技术依据。     

食品中的免疫调节功能因子研究进展

经过自然进化,人类免疫系统与各种天然食品资源相适应。利用天然资源中的功能因子调节人体免疫系统成为一项重要的研究内容。调节免疫功能是我国保健食品可以申报的27项功能之一,在伤病员康复、预防炎症和慢性疾病、增强体质等方面具有重要作用。本文综述了氨基酸、维生素、ω-3多不饱和脂肪酸、黄酮和异黄酮类、多酚类、类胡萝卜素等免疫调节功能因子及其调节机理的研究进展。     

乳酸菌促生长因子的研究

乳酸菌属于肠道内的有益菌,对调节人体健康有益,其生长能力和活性受外界条件的影响.促生长因子是一类对微生物生长繁殖具有促进作用的物质,可用于有效提高乳酸菌数量和活性.围绕乳酸菌促生长因子与益生元的关系及其来源、类别和作用机理等方面,综述其在乳酸菌上的研究与应用,并对未来发展方向进行了展望,以期为促生长因子在乳酸菌产业中的...     

乳酸菌与肠粘膜免疫

1　乳酸菌在胃肠道的分布胃肠道由复杂的生态系统组成 ,至今已被分离、鉴定的菌种有 40 0多种 ,以严格厌氧菌为主。据统计 :人体的微生物数目达到 10 1 3～ 10 1 4 个 ,超过了人体细胞总数 ,而肠道中的微生物又是最重要的。表 1　胃肠道中乳酸菌的分布 [1 ]部位组成菌体浓度 (CFU/ml)胃十二指肠、空肠回肠结肠StreptococcusLactobacillus与胃相似BacteriodesClostridiumStreptococci LactobacillusBacteriodesEubacteriumClostridium PeptococcusBifidobacteriumFusobacterium Streptococcus10 1～ 10 2*10 2 ～ 10 410 6～ 10 8***1…     

降解嘌呤核苷乳酸菌的筛选及益生特性探索

【背景】高尿酸血症是人体内嘌呤代谢紊乱导致的一种慢性代谢疾病,利用乳酸菌降解嘌呤类物质是辅助治疗高尿酸血症的新方法。【目的】筛选高效降解嘌呤核苷的乳酸菌并对其益生特性进行研究。【方法】利用HPLC法评价乳酸菌对肌苷、鸟苷的降解效果。通过药敏性试验、体外耐受性试验及细胞黏附试验研究目标菌株的益生特性。【结果】筛选出一株发酵乳杆菌(Lactobacillus fermentum) SR2-6,对肌苷和鸟苷的降解率分别为99.26%和98.85%。该菌株对青霉素、氯霉素等5种常见抗生素不具备耐药性,在pH 2.0环境下处理4 h后菌株的存活率为76.51%,在饱腹状态下的人工肠液模拟消化4 h后活菌数仍能达到6.85 lg (CFU/mL),对Caco-2细胞的黏附数为(52.29±15.14) CFU/cell。【结论】发酵乳杆菌SR2-6能够高效降解肌苷和鸟苷且具有优良的益生特性,是预防和治疗高尿酸血症的潜在优势菌株,可作为优势菌种资源应用于相关功能产品的开发。     

圈养大熊猫肠道乳酸菌分离及益生特性

【背景】大熊猫数量稀少、繁殖困难,在其生长过程中极易感染消化系统疾病甚至死亡。【目的】分析圈养大熊猫肠道可培养乳酸菌的群落结构与功能,筛选具有益生特性的乳酸菌菌株,为大熊猫消化系统疾病的预防和肠道微生物研究提供理论参考及菌种资源。【方法】采用3种培养基分离大熊猫粪便中的乳酸菌,通过革兰氏染色镜检和过氧化氢试验对分离的菌株进行初步鉴定,基于BOXA1R-PCR图谱遗传多样性选取代表菌株进行16S rRNA基因测序分析并进行主成分分析(principal component analysis, PCA),同时分析乳酸菌菌株安全性和益生特性。【结果】通过初步鉴定共分离获得58株乳酸菌,根据BOXA1R-PCR结果挑选20株菌进行测序,结果显示20株菌分属于明串珠菌属(Leuconostoc)、肠球菌属(Enterococcus)、魏斯氏菌属(Weissella)和链球菌属(Streptococcus)这4个属,主成分分析结果表明不同年龄段的大熊猫肠道乳酸菌群落结构存在差异。20株乳酸菌均不溶血,17株乳酸菌对11种抗生素均敏感;11株菌耐pH值2.0酸性条件,14株菌对0.3%的胆盐具有良好...     

肠粘膜上皮细胞在粘膜免疫调节中的作用

肠粘膜上皮细胞是调节宿主粘膜表面自然免疫与获得性免疫的主要细胞。近年来的研究证实,IECS可以发挥多种免疫调节功能,如抗原提呈功能,分泌细胞因子,表达粘附分子等,本文重点介绍其分泌的几种细胞因子包括IL－1 Ra,IL-7,IL-8,TGF-β,SCF等与其免疫学功能的关系。     

乳酸菌保肝护肝的研究进展

目的 本研究介绍了酒精性肝损伤机制,乳酸菌抗氧化及保肝护肝的研究进展,并且对乳酸菌抗氧化的体内和体外实验进行了总结.     

Effect of gastric and small intestinal digestion on lactic acid bacteria activity in a GIS1 simulator

The selection of probiotic strains resistant to gastrointestinal transit is an important stage when developing supplements that contain viable biomass. A total of six strains belonging to different genotypes were tested and compared with both a positive and negative control (Lactobacillus plantarum 5s). Significant differences were found between strains as a result of gastrointestinal transit using the in vitro GIS1 static simulator. The Lactobacillus rhamnosus 428ST strain showed maximum viability as a result of in vitro transit, featuring a survival capacity value, Cs, of over 50 ± 0.01%. The remaining genotypes that were tested showed significant reductions in the enzymes and bile salts at the time of action. The value of the survivability capacity was directly correlated with the synthesis of exopolysaccharides and lactic acid. The test results of the GIS1 system have been compared with those of other studies on gastrointestinal transit resistance that used dynamic models.     

Responses of lactic acid bacteria to oxygen

Abstract A small number of flavoprotein oxidase enzymes are responsible for the direct interaction of lactic acid bacteria (LAB) with oxygen; hydrogen peroxide or water are produced in these reactions. In some cultures exposed to oxygen, hydrogen peroxide accumulates to inhibitory levels.
Through these oxidase enzymes and NADH peroxidase, O₂ and H₂O₂ can accept electrons from sugar metabolism, and thus have a sparing effect on the use of metabolic intermediates, such as pyruvate or acetaldehyde, as electron acceptors. Consequently, sugar metabolism in aerated cultures of LAB can be substantially different from that in unaerated cultures. Energy and biomass yields, end-products of sugar metabolism and the range of substrates which can be metabolised are affected.
Lactic acid bacteria exhibit an inducible oxidative stress response when exposed to sublethal levels of H₂O₂. This response protects them if they are subsequently exposed to lethal concentrations of H₂O₂. The effect appears to be related to other stress responses such as heat-shock and is similar, in some but not all respects, to that previously reported for enteric bacteria.     

Heteropolysaccharides from lactic acid bacteria

Microbial exopolysaccharides are biothickeners that can be added to a wide variety of food products, where they serve as viscosifying, stabilizing, emulsifying or gelling agents. Numerous exopolysaccharides with different composition, size and structure are synthesized by lactic acid bacteria. The heteropolysaccharides from both mesophilic and thermophilic lactic acid bacteria have received renewed interest recently. Structural analysis combined with rheological studies revealed that there is considerable variation among the different exopolysaccharides; some of them exhibit remarkable thickening and shear-thinning properties and display high intrinsic viscosities. Hence, several slime-producing lactic acid bacterium strains and their biopolymers have interesting functional and technological properties, which may be exploited towards different products, in particular, natural fermented milks. However, information on the biosynthesis, molecular organization and fermentation conditions is rather scarce, and the kinetics of exopolysaccharide formation are poorly described. Moreover, the production of exopolysaccharides is low and often unstable, and their downstream processing is difficult. This review particularly deals with microbiological, biochemical and technological aspects of heteropolysaccharides from, and their production by, lactic acid bacteria. The chemical composition and structure, the biosynthesis, genetics and molecular organization, the nutritional and physiological aspects, the process technology, and both food additive and in situ applications (in particular in yogurt) of heterotype exopolysaccharides from lactic acid bacteria are described. Where appropriate, suggestions are made for strain improvement, enhanced productivities and advanced modification and production processes (involving enzyme and/or fermentation technology) that may contribute to the economic soundness of applications with this promising group of biomolecules.     

乳酸菌合成叶酸的研究进展

叶酸普遍存在于各类食物中,但由于叶酸的不稳定性以及饮食习惯的差异性,各国叶酸缺乏现象普遍存在。叶酸是参与核酸合成及细胞分裂分化的重要物质,叶酸缺乏引起机体功能的混乱,由此引发癌症等一系列的疾病。大部分乳酸菌是叶酸缺陷型菌株,但越来越多的研究表明其很多种类都具有叶酸合成能力。本文主要概述产叶酸乳酸菌的分类,乳酸菌生物合成叶酸的机制,以及利用乳酸菌进行的叶酸基因工程研究进展。     

乳酸菌代谢组学研究进展

代谢组学作为系统生物学的重要分支,近年来在微生物研究领域受到广泛关注,并取得了重要进展。目前乳酸菌代谢组学正日益成为研究的热点,就乳酸菌代谢组学研究中有关样品的制备、分析鉴定和数据分析等涉及的主要方法进行概述,并介绍一些乳酸菌代谢组学应用的典型实例,对乳酸菌代谢组学研究中潜在的问题和未来发展趋势进行讨论。     

产生物胺乳酸菌的筛查与检测

目的对上海市场上食品和药品中分离出的20株乳杆菌,13株链球菌,3株乳球菌和3株肠球菌的产生物胺能力进行检测,以揭示其潜在的安全性问题。方法检测的生物胺共包括6种：分别为酪胺、精胺、尸胺、组胺、腐胺和色胺。利用添加了前体氨基酸的氨基酸脱羧酶筛选培养基对各菌株的产胺能力进行初筛,通过培养基中指示剂的颜色变化判定产胺能力。结果在检测的39株菌中,8株菌具有产酪胺的能力,7株菌具有产精胺的能力,1株菌具有产组胺的能力,1株菌具有产腐胺的能力。尤其是精胺和酪胺的产量较为引人关注。结论生物胺的危害水平取决于个体解毒的能力,但在筛选食品药品用菌株时应运用规范的方法来检测其产生物胺的能力,以保障相应食品药品的安全问题。     

乳酸菌对重金属吸附作用的研究进展

重金属污染是人们关注的食品安全问题热点之一,使用食品安全级乳酸菌吸附重金属成为了新的研究方向。本文在分析环境和食品中汞、镉、铅污染的来源及对人类危害的基础上,对微生物与重金属的相互作用进行介绍,重点归纳了乳酸菌作为重金属吸附剂的潜能,以及吸附重金属的作用机制和研究现状,为研发高效吸附重金属的乳酸菌吸附剂提供了可行性的思路。     

Probiotic potential of lactic acid bacteria isolated from chicken gastrointestinal digestive tract

This study was conducted in order to evaluate the probiotic properties of lactic acid bacteria (LAB) isolated from intestinal tract of broilers and Thai indigenous chickens. The major properties, including the gastric juice and bile salts tolerance, starch, protein and lipid digesting capabilities, and the inhibition on certain pathogenic bacteria were investigated. Three-hundred and twenty-two and 226 LAB strains were isolated from ten broilers and eight Thai indigenous chickens, respectively. The gastrointestinal transit tolerance of these 548 isolates was determined by exposing washed cell suspension at 41°C to simulated gastric juice (pH 2.5) containing pepsin (3 mg ml⁻¹), and to simulated small intestinal juice (pH 8.0) in the presence of pancreatin (1 mg ml⁻¹) and 7% fresh chicken bile, mimicking the gastrointestinal environment. The survival of 20 isolates was found after passing through the gastrointestinal conditions. The survival rates of six strains; KT3L20, KT2CR5, KT10L22, KT5S19, KT4S13 and PM1L12 from the sequential study were 43.68, 37.56, 33.84, 32.89, 31.37 and 27.19%, respectively. Twelve isolates exhibited protein digestion on agar plate but no isolates showed the ability to digest starch and lipid. All 20 LAB showed the antimicrobial activity against Salmonella sp., Staphylococcus aureus and Escherichia coli except one strain which did not show the inhibitory activity toward E. coli. Accordingly, five isolates of selected LAB (KT2L24, KT3L20, KT4S13, KT3CE27 and KT8S16) can be classified as the best probiotics and were identified as Enterococcus faecalis, Enterococcus durans, Enterococcus faecium, Pediococcus pentosaceus, and Enterococcus faecium, respectively. The survival rate of microencapsulation of E. durans KT3L20 under simulated small intestine juice after sequential of simulated gastric juice was also investigated. An extrusion technique exhibited a higher survival rate than emulsion technique and free cell, respectively.     

乳酸菌肽聚糖的研究进展

肽聚糖是乳酸菌细胞壁的必需成分,它的化学结构较为保守固定,而其合成是一个涉及多步反应的复杂过程。乳酸菌肽聚糖具有多种生物学活性,比如免疫增强功能、抗感染、抗肿瘤及抗过敏等。本文对乳酸菌肽聚糖的组成结构和生物学活性进行了简要的介绍,重点综述了近年来乳酸菌肽聚糖代谢及其调控过程的研究进展,并指出了乳酸菌肽聚糖未来研究的方向。