猪源乳酸菌产乳酸及其抑菌特性研究

研究了5株(L1、12、L3、L5和L7)分离自仔猪肠道的乳酸菌的产乳酸能力及抑菌特性。结果表明：L5菌株产乳酸的速度最快,培养液中乳酸含量最高,L5菌株培养液pH值的下降速度最快,终末pH值最低,而L1菌株产乳酸的速度最慢,培养液乳酸含量最低。5株乳酸菌对大肠杆菌K88、K99、987P、O141和大肠杆菌E1及金黄色葡萄球菌均有不同程度的抑制作用;排除酸的影响后仍有22％～53％抑菌效果;经热处理后保持有92％以上的抑菌效果;蛋白酶处理后保持85％以上的抑菌效果。     

乳酸菌降胆固醇作用研究现状

本文综述了国内外关于乳酸菌在体内及体外降低胆固醇的研究进展, 并对乳酸菌降胆固醇的作用机制进行了探讨, 提出目前在研究中存在的一些问题, 以期对乳酸菌的进一步开发和利用提供帮助。     

苯乳酸生物合成的研究进展*

苯乳酸是一种天然无毒且具有广谱抑菌作用的新型生物防腐剂,可由多种不同的微生物代谢产生,大多数乳酸菌都能够代谢生成苯乳酸。苯乳酸应用广泛,不仅能够应用于食品行业抑制多种病原菌,还可以广泛应用于医药和化工业。对苯乳酸的特性和应用以及其生物合成进行了综述,以期对苯乳酸及其生物合成有较系统的了解。     

苯乳酸生物合成的研究进展*

苯乳酸是一种天然无毒且具有广谱抑菌作用的新型生物防腐剂,可由多种不同的微生物代谢产生,大多数乳酸菌都能够代谢生成苯乳酸。苯乳酸应用广泛,不仅能够应用于食品行业抑制多种病原菌,还可以广泛应用于医药和化工业。对苯乳酸的特性和应用以及其生物合成进行了综述,以期对苯乳酸及其生物合成有较系统的了解。     

具有降胆固醇作用乳酸菌的研究和开发进展

本文综述了国内外关于具有降胆固醇作用的乳酸菌的降胆固醇作用和作用机制的研究进展,同时总结了降胆固醇乳酸菌在食品发酵和医疗保健方面的应用,提出以后研究的重点,以期对乳酸菌的进一步开发和利用提供帮助。     

猪源乳酸菌产乳酸及其抑菌特性研究*

研究了5株(L1、L2、L3、L5和L7)分离自仔猪肠道的乳酸菌的产乳酸能力及抑菌特性。结果表明:L5菌株产乳酸的速度最快,培养液中乳酸含量最高,L5菌株培养液pH值的下降速度最快,终末pH值最低,而L1菌株产乳酸的速度最慢,培养液乳酸含量最低。5株乳酸菌对大肠杆菌K88、K99、987P、O141和大肠杆菌E1及金黄色葡萄球菌均有不同程度的抑制作用;排除酸的影响后仍有22%～53%抑菌效果;经热处理后保持有92%以上的抑菌效果;蛋白酶处理后保持85%以上的抑菌效果。     

一株植物乳杆菌Lp3对高脂模型大鼠的益生作用

【目的】本研究通过构建大鼠高脂结构模型来探究一株植物乳杆菌Lp3的益生作用。【方法】植物乳杆菌Lp3筛选自青藏高原地区传统发酵的牦牛酸奶,初步认定Lp3是一株具有良好耐受力的降胆固醇菌株,且体外益生特性突出,本研究通过建立高脂SD大鼠模型,在饲喂试验动物高脂饲料的同时灌胃植物乳杆菌Lp3,来确定该菌株对试验动物血脂的影响效果,并同时研究其对大鼠肠道菌群、粪便水分、粪便中胆固醇和胆汁酸含量的影响,以及对肝脏组织中的胆固醇(TC)和甘油三酯(TG)的影响。【结果】结果表明,植物乳杆菌Lp3对大鼠没有任何明显的毒副作用,对高脂模型大鼠具有良好的降血脂效果。饲喂高脂饲料并灌喂乳酸菌Lp3组大鼠(HL)的血清总胆固醇、甘油三酯和低密度脂蛋白胆固醇含量较饲喂高脂饲料组(HC)显著减少(P0.05),但是高密度脂蛋白胆固醇的含量变化并不明显。HC组大鼠与HL组及饲喂普通日粮组(对照组)大鼠相比较,HC组大鼠粪便中大肠杆菌数量明显增加,双歧杆菌、乳杆菌数量明显减少。但是灌胃乳酸菌的HL组大鼠的粪便中乳杆菌数略高于对照组,大肠杆菌和双歧杆菌数量和对照组大鼠的基本一致。表明植物乳杆菌Lp3具有维持肠道菌群平衡的作用。此外灌胃乳酸菌后HL组大鼠粪便含水量比HC组要高6.44%。HC组大鼠肝脏组织中胆固醇和甘油三酯要显著高于HL组(P0.05),说明Lp3可以减少脂类物质在肝脏组织中的沉积。从肝脏组织切片来看,也可以得出上述结论。【结论】结果表明本研究所筛选的植物乳杆菌Lp3对高脂大鼠具有值得深入研究的益生作用。     

降胆固醇乳酸菌的筛选及应用的研究进展

胆固醇摄入过量带来的高脂血症、冠心病、动脉硬化等心血管疾病已经严重危害到人体健康,如何减少胆固醇摄入量、降低人体血清胆固醇水平的研究越来越受到广泛关注^[1]。美国的一项统计调查^[2]发现,高脂血症所引起的心血管疾病是目前危害人类健康,导致死亡的首要因素。而另一项最近的研究报告^[3]证实,降低血清胆固醇含量将有助于降低高脂血症患者患上心脏疾病的几率。因此,降低血清胆固醇含量将直接关系到人类的健康,也是目前国内外科学研究的热点之一。     

乳酸菌降低血清胆固醇的研究

本文综述了乳酸菌对血清胆固醇的降低作用,并对其作用机制进行了探讨,这将有助于对乳酸菌资源的进一步开发和利用。     

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.     

基因工程乳酸菌的应用研究进展

随着分子生物学技术的不断发展,重组基因工程乳酸菌取得了较快的进展.本文主要从基因工程乳酸菌在食品、药品、保健品、饲料养殖领域中的应用进行综述,以便正确认识、了解和使用基因工程乳酸菌,对其进一步的研究以及开发应用具有深远的意义.     

Phenotypic Assessment of Probiotic and Bacteriocinogenic Efficacy of Indigenous LAB Strains from Human Breast Milk

Breast milk is the combination of bioactive compounds and microflora that promote newborn’s proper growth, gut flora, and immunity. Thus, it is always considered the perfect food for newborns. Amongst their bioactives, probiotic communities—especially lactic acid bacteria (LAB)—are characterized from breast milk over the first month of parturition. In this study, seven LAB were characterized phenotypically and genotypically as Levilactobacillus brevis BDUMBT08 ({"type":"entrez-nucleotide","attrs":{"text":"MT673657","term_id":"1863149999"}}MT673657), L. gastricus BDUMBT09 ({"type":"entrez-nucleotide","attrs":{"text":"MT774596","term_id":"1873222494"}}MT774596), L. paracasei BDUMBT10 ({"type":"entrez-nucleotide","attrs":{"text":"MT775430","term_id":"1874262304"}}MT775430), L. brevis BDUMBT11 ({"type":"entrez-nucleotide","attrs":{"text":"MW785062","term_id":"2009762994"}}MW785062), L. casei BDUMBT12 ({"type":"entrez-nucleotide","attrs":{"text":"MW785063","term_id":"2009820773"}}MW785063), L. casei BDUMBT13 ({"type":"entrez-nucleotide","attrs":{"text":"MW785178","term_id":"2010296340"}}MW785178), and Brevibacillus brevis M2403 ({"type":"entrez-nucleotide","attrs":{"text":"MK371781","term_id":"1548854744"}}MK371781) from human breast milk. Their tolerance to lysozyme, acid, bile, gastric juice, pancreatic juice, and NaCl and potential for mucoadhesion, auto-aggregation, and co-aggregation with pathogens are of great prominence in forecasting their gut colonizing ability. They proved their safety aspects as they were negative for virulence determinants such as hemolysis and biofilm production. Antibiogram of LAB showed their sensitivity to more than 90% of the antibiotics tested. Amongst seven LAB, three isolates (L. brevis BDUMBT08 and BDUMBT11, and L. gatricus BDUMBT09) proved their bacteriocin producing propensity. Although the seven LAB isolates differed in their behavior, their substantial probiotic properties with safety could be taken as promising probiotics for further studies to prove their in vivo effects, such as health benefits, in humans.     

乳酸菌对高脂小鼠降胆固醇作用的研究

目的探讨乳酸菌对高脂小鼠降胆固醇的作用。方法对昆明小鼠饲喂高脂饲料14 d建立高脂小鼠模型,确定模型建立成功后用1株经体外实验证实具有降胆固醇效果的乳酸菌对小鼠灌胃,测定小鼠经灌胃14、28 d的脏器指数、血清胆固醇含量和肝脏胆固醇含量。结果灌胃组小鼠脏器指数明显低于高脂组小鼠,且对于血清和肝脏胆固醇含量具有明显的降低作用。结论该菌株具有降低血清胆固醇,抑制肝脏胆固醇堆积的功能,为将来利用该菌株制作出降胆固醇功能的食品或药品提供实验基础。     

蒙古国地区酸乳中乳酸菌的鉴定及耐酸菌株筛选

本研究对采集自蒙古国地区牧民家庭中17份发酵乳样品中的乳杆菌进行了分离、鉴定、生物学特性和耐酸性研究。共分离出45株乳杆菌。通过形态观察、生理生化试验、糖发酵试验及16S rDNA序列分析等研究将这些菌株鉴定为Lactobacillum fermentum(L. fermentum)31 株, L. helveticus 12株, L. plantarum 1株 和L. casei 1株, 所以认为L. fermentum是蒙古国地区传统酸乳中的优势菌群。经pH 为3.0 的人工胃液耐受性试验复筛后发现, 存活率在80%以上的仅1株, IMAU20085的存活率高达81.44%。菌株的分离鉴定以及高耐酸性菌株的筛选, 对我国益生菌资源的保藏和开发有重要的意义, 对我国未来益生菌的开发具有重要价值。     

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.     

Probiotic characteristics of lactic acid bacteria isolated from kimchi

Aims: The present work was aimed at identifying strains of lactic acid bacteria (LAB) from kimchi, with properties suitable for use as starter cultures in yogurt fermentation. Methods and Results: A total of 2344 LAB strains were obtained from two different sources, one group consisted of commercial LAB strains from kimchi, and the second group consisted of those strains isolated from various types of kimchi. The LAB strains from both groups were screened for resistance to biological barriers (acid and bile salts), and the four most promising strains were selected. Further analysis revealed that KFRI342 of the four selected strains displayed the greatest ability to reduce the growth of the cancer cells, SNU‐C4. The in vivo efficacy of strains in quinone reductase induction assay was evaluated, and the extent of DNA strand breakage in individual cells was investigated using the comet assay. Strain KFRI342 was identified as Lactobacillus acidophilus by 16S rRNA sequence analysis, showed protection against tumour initiation and imparted immunostimulation as well as protection against DNA damage. Conclusions: Strain KFRI342, which showed probiotic characteristics reducing cancer cell growth, could be a suitable starter culture for yogurt fermentation because of its strong acid production and high acid tolerance. Significance and Impact of the Study: This is the first report to describe a bacterium, isolated from kimchi, Lact. acidophilus KFRI342 which has the probiotic characteristics and the acid tolerance needed for its use as a starter culture in yogurt fermentation.     

Probiotic potential of lactic acid bacteria isolated from fermented dairy milks on antiproliferation of colon cancer cells

Fifty-four strains of lactic acid bacteria obtained from fermented dairy milks were investigated for possible use as probiotics and for colon cancer biological products. Five of these strains inhibited growth of eight food-borne pathogens including Helicobacter pylori, Escherichia coli, and Salmonella typhimurium. Three of these strains survived at pH 2.5 and in 0.3% bile salts. Additionally they produced no haemolysis, were resistant to kanamycin and adhered to Caco-2 cells. 16S rRNA gene sequences of probiotic strains indicated that RM11 and RM28 were Enterococcus faecium and Lactobacillus fermentum, respectively. Both the cultured medium and live whole cells from probiotic strains were tested for antiproliferation of colon cancer cells through MTT and Trypan Blue exclusion assays. The probiotic strains of E. faecium RM11 and L. fermentum RM28 also triggered antiproliferation of colon cancer cells at the rates of 21–29%, and 22–29%, respectively. This suggested that both strains could be used as potential probiotics in functional food or for colon cancer biological products. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.