乳酸菌粘附的机制、特点、生物学作用

目前微生态制剂迅猛发展,乳酸菌是微生态制剂中应用最为广泛,效果较好的一类。美国FDA批准用作直接饲喂的微生物已有43种,其中乳酸菌28种,我国农业部允许使用的饲料微生物添加剂有12种,其中乳酸菌7种。双歧杆菌、乳酸杆菌是肠道最重要也是最具代表性的生理性细菌,它们对宿主发挥生物屏障、营养、免疫、抗肿瘤等生理作用。粘附是微生物与宿主相互关系的先决条件之一,     

酸奶能够克服“乳糖不耐受”的原因探究

随着人们生活水平的提高和对营养健康的关注,牛奶成了家庭必备的食品。但有些人喝牛奶会腹胀、腹泻,而喝酸奶会避免这个症状。通过上网查阅资料,采访专家,参考文献,开展社会调研,亲自制作酸奶,实地考察酸奶生产线,以及对对酸奶成分进行检测后,发现喝牛奶腹胀、腹泻的现象(乳糖不耐受)较为普遍,其主要原因是体内缺乏乳糖酶的人群不能分解牛奶中的乳糖所致。酸奶与牛奶的加工工艺不同,在发酵过程中20%-30%的乳糖被分解,含量明显下降,易于人体消化吸收。加之酸奶中的活性乳酸菌的代谢物可增加小肠乳糖水平,从而有效缓解和克服了乳糖不耐受的症状。     

微生态制剂联合肠内营养对食管癌患者术后肠功能及营养状况的影响

目的探讨微生态制剂联合肠内营养对食管癌患者术后肠功能及营养状况的影响。方法选取2018年6月至2018年12月我院胸外科食管癌术后患者58例,随机分为观察组(n=27)和对照组(n=31)。对照组患者术后采用常规肠内肠外联合营养支持方案,观察组患者在对照组基础上给予微生态制剂(活菌型乳酸菌乳饮品)鼻饲。比较两组患者腹胀、腹泻的发生率,通气时间,首次排便时间,留置胃管时间,住院时间,住院总费用,血红蛋白、前白蛋白、转铁蛋白、白蛋白、视黄醇结合蛋白水平及出院时BMI值的变化。结果观察组患者术后发生腹胀和腹泻的比率明显低于对照组,通气时间、首次排便时间均早于对照组(P<0.05)。观察组患者首次饮水时间提前,胃管置留天数及术后住院天数也较对照组缩短(P<0.05)。两组患者出院时BMI值比较差异具有统计学意义(P<0.05)。结论微生态制剂(活菌型乳酸菌乳饮品)联合肠内营养能改善食管癌患者术后的肠功能,降低肠内营养不耐受的发生率,有利于肠内营养的实施,促进患者康复。     

林麝复合微生物制剂的研制

本研究采用林麝肠道分离的3株乳酸菌研制一种复合微生态制剂,对复合微生态制剂进行了不同配比的选择、昆明小鼠安全性试验、活菌数的监测和林麝的应用。结果显示:作为最优配比的复合微生态制剂C(S2∶S3∶MRS2-2=1∶1∶2),安全性试验结果显示其未引起小白鼠机体的不良反应;在14 d时,储存温度为-20℃下复合微生态制剂的活菌数降至1.43E+08 CFU/m L;用复合微生态制剂C治疗林麝肠道致病性大肠杆菌感染的昆明小鼠,结果显示微生态制剂组肠道乳酸菌显著大于空白组和感染组(P0.05),复合微生态制剂治疗腹泻林麝,治愈率为50%。本试验首次研制了一种林麝复合微生态制剂,对于提高林麝人工养殖的存活率有指导意义。     

乳糖吸收不良、乳糖不耐受与人体健康关系探讨

由于乳糖在人体生长发育和新陈代谢中发挥着重要作用,乳糖吸收不良(Lactose malabsorption,LM)或乳糖不耐受症(Lactose intolerance,LI)不仅可诱发小儿佝偻病、成人骨质疏松,而且还可造成人体腹泻、影响婴幼儿脑组织和神经系统的构建,对婴幼儿的体格发育和智力发育造成损害。本研究对乳糖不耐受的病因及发病因素、分型、流行病学、临床及实验室诊断方法等作一概述,为临床实践和科学研究提供参考。     

微生态制剂在肠内营养治疗的研究进展与应用

临床营养支持是以治疗或缓解疾病、增强治疗效果为目的,根据营养学原理采取的营养措施,主要可以分为肠外营养( Parenteral Nutrition,PN)和肠内营养(Enteral Nutrition,EN).今年来,随着医学研究与认识的加深,肠道的重要性越来越被人们所认识到.美国WILMORE曾提出肠道是外科应激反应的"中心脏器"学说[1].因此与肠外营养相比,肠内营养显得越发重要.人体肠道是一个巨大而复杂的微生态系统,其各种菌群之间的平衡对于人体的健康和疾病恢复有着重要的意义.微生态制剂( Microecologics)又称为微生态调节剂(Microecological).是根据微生态学基本原理,利用人体正常菌群成员或对其有促进作用的其他微生物等物质制成的生物制品.它具有调整微生态失调、恢复微生态平衡、促进宿主健康的作用.因此将微生态制剂应用于肠内营养有着明显的优势,同时也是目前临床营养支持的发展趋势.     

乳酸菌制剂的研究与应用前景

乳酸菌制剂是一种微生态制剂,具有无毒副作用及应用广泛的特点。简要介绍了乳酸菌制剂的种类、作用机制、研究前景、存在问题等,为乳酸菌制剂的研究提供参考。     

作用于奶牛生殖系统的乳酸菌菌属研究进展

乳酸菌菌属作为治疗性微生态制剂具有安全有效、无耐药性、环保无残留的优势,因其优势可成为治疗奶牛生殖道疾病的抗生素替代物之一。本研究就乳酸菌作用于奶牛生殖系统各个靶器官的研究概况,乳酸菌补给途径以及其作用机制进行了综述。     

昆明市儿童医院治疗腹泻用药品种分析

目的分析小儿腹泻用药品种,为临床用药、药品购进提供参考。方法统计昆明市儿童医院１９９６年８月至１９９８年８月西药库帐目统计、药品消耗之品种,分两年进行比较分析,按各品种消耗量多少排列顺序。结果１９９６年８月至１９９７年８月为：乳酶片,多酶片,古胺卡那,思密达,乳酸菌素,先锋铋,小儿痢宝,回春生,妈噗爱,培菲康,米雅。１９９７年９月至１９９８年８月为：乳酸菌素,促菌生,妈咪爱,回春生,先锋铋,思密达,乳酶生,多酶,丁胺卡那,培菲康,米雅。两年的比较显示：微生态调节剂的应用有明显上升趋势,尤其益生菌制剂更为突出居上。讨论随着肠道微生态的深入认识和微生态制剂的临术应用,对小儿腹泻的治疗以基于益生菌种有害菌的认识,重视到肠道菌群平衡的问题。小儿一方面由于免疫系统还不成熟,机体很容易感染各种疾病,另一方面由于采用抗生素治疗,使正常菌群发生改变,生态失调,引起菌群交替症,导致腹泻。因此使用微生态制剂治疗,使之肠道内保持一个安定的生态平衡的正常肠内菌群,对于包括各种病原菌在内的外籍菌引起的肠道感染具有明显的抵抗力就格外显得重要。结论临床应用微生态调节剂取得良好疗效,尤其益生菌活菌制剂的应用,为小儿腹泻拓宽了一条新路     

益生菌制剂治疗极低出生体重儿喂养不耐受的临床研究

目的探讨益生菌制剂对极低出生体重儿（very low birth weight infant,VLBW）喂养不耐受的影响。方法将56例极低出生体重儿随机分成治疗组和对照组,每组28例。2组均予静脉营养及早产儿配方奶喂哺,治疗组在早产儿配方奶喂哺时添加益生菌制剂,每次0．5g,3次／d,2组同时记录恢复出生体重时间、达全胃肠喂养时间及黄疽消退时间。结果治疗组恢复出生体重时间、达全胃肠喂养时间均显著短于对照组（P〈0．01）,治疗组黄疸消退时间也明显缩短（P〈0．05）。微生态制剂治疗过程中无不良反应发生。结论益生菌制剂可改善极低出生体重儿喂养不耐受,促进患儿体重增长,缩短达到全胃肠喂养时间,值得推广应用。     

Genetics of lactose utilization in lactic acid bacteria

Abstract: Lactose utilization is the primary function of lactic acid bacteria used in industrial dairy fermentations. The mechanism by which lactose is transported determines largely the pathway for the hydrolysis of the internalized disaccharide and the fate of the glucose and galactose moieties. Biochemical and genetic studies have indicated that lactose can be transported via phosphotransferase systems, transport systems dependent on ATP binding cassette proteins, or secondary transport systems including proton symport and lactose-galactose antiport systems. The genetic determinants for the group translocation and secondary transport systems have been identified in lactic acid bacteria and are reviewed here. In many cases the lactose genes are organized into operons or operon-like structures with a modular organization, in which the genes encoding lactose transport are tightly linked to those for lactose hydrolysis. In addition, in some cases the genes involved in the galactose metabolism are linked to or co-transcribed with the lactose genes, suggesting a common evolutionary pathway. The lactose genes show characteristic configurations and very high sequence identity in some phylogenetically distant lactic acid bacteria such as Leuconostoc and Lactobacillus or Lactococcus and Lactobacillus . The significance of these results for the adaptation of lactic acid bacteria to the industrial milk environment in which lactose is the sole energy source is discussed.     

Potential of using lactic acid bacteria for therapy and immunomodulation in man

Abstract: There is in 1993 no proven medical indication of lactic acid bacteria (LAB) for therapy or immunomodulation in man. However, within the bulk of publications, rigorous trials have now opened rational fields of research on beneficial effects of LAB. These include lactose digestion, cholesterol metabolism, diarrheal disorders, prophylaxis of intestinal or urogenital infections, immunomodulation or even oral vaccination. We try here to analyse these studies, considering LAB as pharmacological agents, and conclude that pursuit of research could be promising for ecological therapy of mucosal diseases, and for development of original and flexible vectors for targeting in the gastrointestinal tract.     

Health and nutritional benefits from lactic acid bacteria

Abstract There are several potential health or nutritional benefits possible from some species of lactic acid bacteria. Among these are: improved nutritional value of food, control of intestinal infections, improved digestion of lactose, control of some types of cancer, and control of serum cholesterol levels. Some potential benefits may result from growth and action of the bacteria during the manufacture of cultured foods. Some may result from growth and action of certain species of the lactic acid bacteria in the intestinal tract following ingestion of foods containing them. In selecting a culture to produce a specific benefit it is necessary to consider not only the wide variation among species of the lactic acid bacteria but also that among strains within a given species. With the possible exception of improving lactose utilization by persons who are lactose maldigestors, no specific health or nutritional claims can yet be made for the lactic acid bacteria.     

乳糖吸收不良、乳糖不耐受与人体健康关系探讨

由于乳糖在人体生长发育和新陈代谢中发挥着重要作用,LM或LI不仅可诱发小儿佝偻病、成人骨质疏松,而且还可造成人体腹泻、影响婴幼儿脑组织和神经系统的构建,对婴幼儿的体格发育和智力发育造成损害。本研究对乳糖不耐受的病因及发病因素、分型、流行病学、临床及实验室诊断方法等做一概述,为临床实践和科学研究提供参考。     

Nutrition,population growth and disease: a short history of lactose

Food and nutrition have played a crucial role in biological evolution. Lactation in mammals was one key invention. A central role in milk is played by lactose, otherwise an exotic sugar in nature. Lactose digestion needs the induction of specialized gut enzymes. This enzyme is shut off in a precisely timed developmental step leading to lactose malabsorption promoting weaning in the young and ovulation in the mother. The lactose–lactase system could thus regulate optimal birth spacing in land mammals. The domestication of cattle promoted milk as a food item also for adult nutrition. This was only possible by two further key inventions: the concomitant domestication of lactic acid bacteria which ferment the non‐digestible lactose to the easily absorbed lactic acid and the mutation to lactase persistence (LP) in adults from dairy societies. This mutation represents one of the strongest selected loci of the human genome. Since no crucial nutritional selective advantage is conferred by LP, its dominance might be the result of indirect effects like the spread of cattle pathogens into humans. Lactase is also temporarily lost in rotavirus and Escherichia coli childhood diarrhoea and persistent diarrhoea is consequently best treated with lactose‐free diets.     

Probiotics and their fermented food products are beneficial for health

Probiotics are usually defined as microbial food supplements with beneficial effects on the consumers. Most probiotics fall into the group of organisms' known as lactic acid-producing bacteria and are normally consumed in the form of yogurt, fermented milks or other fermented foods. Some of the beneficial effect of lactic acid bacteria consumption include: (i) improving intestinal tract health; (ii) enhancing the immune system, synthesizing and enhancing the bioavailability of nutrients; (iii) reducing symptoms of lactose intolerance, decreasing the prevalence of allergy in susceptible individuals; and (iv) reducing risk of certain cancers. The mechanisms by which probiotics exert their effects are largely unknown, but may involve modifying gut pH, antagonizing pathogens through production of antimicrobial compounds, competing for pathogen binding and receptor sites as well as for available nutrients and growth factors, stimulating immunomodulatory cells, and producing lactase. Selection criteria, efficacy, food and supplement sources and safety issues around probiotics are reviewed. Recent scientific investigation has supported the important role of probiotics as a part of a healthy diet for human as well as for animals and may be an avenue to provide a safe, cost effective, and 'natural' approach that adds a barrier against microbial infection. This paper presents a review of probiotics in health maintenance and disease prevention.     

Lactococcus lactis expressing food-grade β-galactosidase alleviates lactose intolerance symptoms in post-weaning Balb/c mice

The endogenous β-galactosidase expressed in intestinal microbes is demonstrated to help humans in lactose usage, and treatment associated with the promotion of beneficial microorganism in the gut is correlated with lactose tolerance. From this point, a kind of recombinant live β-galactosidase delivery system using food-grade protein expression techniques and selected probiotics as vehicle was promoted by us for the purpose of application in lactose intolerance subjects. Previously, a recombinant Lactococcus lactis MG1363 strain expressing food-grade β-galactosidase, the L. lactis MG1363/FGZW, was successfully constructed and evaluated in vitro. This study was conducted to in vivo evaluate its efficacy on alleviating lactose intolerance symptoms in post-weaning Balb/c mice, which were orally administered with 1?×?10⁶?CFU or 1?×?10⁸?CFU of L. lactis MG1363/FGZW daily for 4?weeks before lactose challenge. In comparison with na?ve mice, the mice administered with L. lactis MG1363/FGZW showed significant alleviation of diarrhea symptoms in less total feces weight within 6?h post-challenge and suppressed intestinal motility after lactose challenge, although there was no significant increase of β-galactosidase activity in small intestine. The alleviation also correlated with higher species abundance, more Bifidobacterium colonization, and stronger colonization resistance in mice intestinal microflora. Therefore, this recombinant L. lactis strain effectively alleviated diarrhea symptom induced by lactose uptake in lactose intolerance model mice with the probable mechanism of promotion of lactic acid bacteria to differentiate and predominantly colonize in gut microbial community, thus making it a promising probiotic for lactose intolerance subjects.     

Identification of bacteria with beta-galactosidase activity in faeces from lactase non-persistent subjects

Previous studies suggest that, besides the maldigestion of lactose in the small intestine, the colonic processing of lactose might play a role in lactose intolerance. beta-Galactosidase is the bacterial enzyme which catalyzes the first step of lactose fermentation in the colon. We propose a practical method to differentiate and identify bacteria with beta-galactosidase activity in faeces which combines a colony-lift filter assay with X-gal (5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside) as substrate for differentiation and the fluorescent in situ hybridization technique for identification. The method was applied to faeces from lactase non-persistent subjects. After 28 subjects had undergone one glucose and two lactose challenges, consistent intolerant (n=5) and tolerant (n=7) groups were defined according to their symptom scores. Of the 28 faecal samples, 80.6% (mean, SD: 12.1, range: 47.8-100%) of the total cultured bacteria were found to possess beta-galactosidase activity, which indicates that the bacterial beta-galactosidase is abundant in the colon. The tolerant and intolerant groups did not differ in the percentage or composition of the bacteria with beta-galactosidase activity or beta-galactosidase activity in faeces. Results suggest that the percentage or composition of the bacteria with beta-galactosidase activity in faeces do not play a role in lactose intolerance.     

Applicability of pectate-entrapped <Emphasis Type="Italic">Lactobacillus casei</Emphasis> cells for <Emphasis Type="SmallCaps">l</Emphasis>(+) lactic acid production from whey

Lactic acid is a versatile organic acid, which finds major application in the food, pharmaceuticals, and chemical industries. Microbial fermentation has the advantage that by choosing a strain of lactic acid bacteria producing only one of the isomers, an optically pure product can be obtained. The production of l(+) lactic acid is of significant importance from nutritional viewpoint and finds greater use in food industry. In view of economic significance of immobilization technology over the free-cell system, immobilized preparation of Lactobacillus casei was employed in the present investigation to produce l(+) lactic acid from whey medium. The process conditions for the immobilization of this bacterium using calcium pectate gel were optimized, and the developed cell system was found stable during whey fermentation to lactic acid. A high lactose conversion (94.37%) to lactic acid (32.95 g/l) was achieved with the developed immobilized system. The long-term viability of the pectate-entrapped bacterial cells was tested by reusing the immobilized bacterial biomass, and the entrapped bacterial cells showed no decrease in lactose conversion to lactic acid up to 16 batches, which proved its high stability and potential for commercial application.     

酸奶发酵剂和乳酸菌生物技术育种

由新鲜牛奶制成的酸奶由于其丰富的营养、特殊的风味、爽滑的质构和良好的生理功能 ,倍受人们青睐。对酸奶乳酸菌的微生物种类、功能及其组成的酸奶发酵剂进行了综述 ,并简要介绍了乳酸菌生物工程育种方面的研究进展及酸奶乳酸菌研究领域一些令人感兴趣的课题。