Bovine lactoferrin region responsible for binding to bifidobacterial cell surface proteins

Bovine lactoferrin promotes bifidobacterial growth. Its binding to bifidobacteria is thought to be responsible for such action. After separating the bovine lactoferrin half molecule and extraction of surface proteins from bifidobacteria, binding profiles were observed by immunoblotting. No binding appeared when lactoferrin C-lobe was reacted with the cell surface proteins on a polyvinylidene difluoride membrane. Conversely, a 50-kDa band appeared when the surface proteins were reacted with either intact or nicked bovine lactoferrin. This result strongly suggests that the binding region could be lactoferrin N-lobe. Interestingly, despite the absence of binding, C-lobe enhanced bifidobacterial growth.     

Screening of Bifidobacterium strains isolated from human faeces for antagonistic activities against potentially bacterial pathogens

As probiotic bacteria, strains belonging to the genus Bifidobacterium colonise the gastro-intestinal tract of humans and animals at the time of birth, and they are found in young as well as in adult individuals in great numbers. Moreover, they can interact with the development of enteric infections by the production of antimicrobial metabolites. In this work 281 strains of bifidobacteria were anaerobically isolated from human faecal samples, supplied by volunteers of different ages (youngs, adults, elders), and preliminarly described by microscopic observation. All strains were screened by the fructose 6-phosphate phosphoketolase (F6PPK) test in order to confirm their classification within the genus Bifidobacterium. Selected strains were used to evaluate their antagonistic activities against Escherichia coli, Salmonella thyphimurium, Staphylococcus lentus, Enterococcus faecalis, Acinetobacter calcoaceticus, Sphingomonas paucimobilis, Listeria monocytogenes, Yersinia enterocolitica, Bacillus cereus, Clostridium sporogenes. Experiments were performed in vitro by different methods based on the observation of growth inhibition in Petri dishes. The strains that showed the highest inhibiting activities were compared by SDS-PAGE for total cell proteins, using type strains of human origin as references. Representative isolates were metabolically characterised by the BIOLOG system; a specific database was created with strains obtained from our collection and a statistical evaluation for metabolic patterns was carried out.     

应用实时荧光定量PCR定量检测溃疡性结肠炎肠道大肠埃希菌、乳酸杆菌及双歧杆菌属的变化

目的应用实时荧光定量PCR（RT—PCR）法对溃疡性结肠炎（ulcerative colitis,UC）患者粪便中大肠埃希菌、乳酸杆菌及双歧杆菌属的数量进行定量检测分析。方法根据细菌的16SrDNA基因序列设计大肠埃希菌、乳酸杆菌及双歧杆菌属的种属特异性引物。收集溃疡性结肠炎患者及正常对照者新鲜粪便标本各35例,从待测粪便标本中提取细菌基因组DNA,进行实时荧光定量PCR反应,定量分析不同细菌的数量。结果正常对照组与病例组粪便中细菌数量分别为大肠埃希菌（4．62±1．10;5．27±1．02）、乳酸杆菌属（4．99±0．75;4．65±0．95）、双歧杆菌属（5．07±0．95;4．93±0．99）,病例组大肠埃希菌数量明显增多（t=2．540,P=0．013）,而乳酸杆菌及双歧杆菌属数量与正常组比较差异无统计学意义（t1=0．488,P,=0．530;t2=-0．533,P：=0．596）。结论溃疡性结肠炎患者粪便中大肠埃希菌的数量较正常对照明显增多,而乳酸杆菌及双歧杆菌属的数量无明显变化,提示大肠埃希菌与溃疡性结肠炎的发病或复发有关系,而乳酸及双歧杆菌属与此病的关系有待进一步研究。     

两歧双歧杆菌中serpin基因的克隆、表达与功能分析

从Bifidobacterium bifidum WBBI02基因组中克隆了serpin基因片段,构建了重组Serpin蛋白的原核表达体系,实现了Serpin的表达与纯化。纯化的Serpin蛋白进行了抑制肠道蛋白酶活性检测,以及对双歧杆菌粘附作用影响的显微观察研究。结果表明:WBBI02中长度为768 bp的serpin基因序列,与GENEBANK中Bifidobacterium longum NCC2705 serpin序列同源性为99. 9 %。原核表达载体pBX₂-WBBI02表达的Serpin能有效地抑制糜蛋白酶和胰弹性蛋白酶的活性,最高抑制率分别为90%和97%,显微观察结果证实Serpin能促进双歧杆菌对HT-29细胞的粘附。     

Modulation of bacterial translocation in mice mediated through lactose and human milk oligosaccharides

Massive resection of the small intestine in infants is imposed to the regulation of several intestinal pathological situations, as intestinal adaptation cannot be relied upon. Many nutritional disturbances are occurring following surgery procedure. In this vein, long-term parenteral feeding is adopt to improve prognosis not always successfully. Clostridia and more specifically Clostridium perfringens, are suspected to participate in the physiopathology of the rising situation. In order to investigate the effect of lactose and human milk neutral oligosaccharides (HMNOs) on Clostridia, germfree mice were inoculated either with enterotoxigenic C.perfringens strain isolated from a patient with NEC, or with a human microbiota harboring C.clostridioforme group(HF). In this vein, different doses of lactose were administrated during 2 weeks in adult mice on an attempt to evaluate the lactase activity. Intake of lactose (70 g/L) and HMNOs (7 g/L) in C.perfringens monoassociated mice induced mortality within a week. In HF mice, no mortality was observed. An increase in Clostridia occurrence was observed in the median ileum after intake of 7 g lactose (p = 0.017). Higher clostridial numbers occurred in caecum following intake of 70 g lactose (p < 0.05) and HMNOs (p < 0.025). Bifidobacteria were found increased from distal ileum to colon following 70 g of lactose intake, whereas they decreased in the caecum of mice drinking lower lactose concentrations. Finally, bacteremia was more frequent in 70 g lactose/L mice (p < 0.02), whereas at lower doses of lactose bifidobacterial translocation was observed.As a result, human milk oligosaccharides could favor clostridial population when reaching the lower intestine. The shortness of the small intestine in infants underwent massive intestinal resection seems to be associated to an incomplete breakdown of lactose. Enteral feeds formulas deprived in lactose would be more suitable in enteral feeding of infants.     

Phylogenetic classification of ten novel species belonging to the genus Bifidobacterium comprising B. phasiani sp. nov., B. pongonis sp. nov., B. saguinibicoloris sp. nov., B. colobi sp. nov., B. simiiventris sp. nov., B. santillanense sp. nov., B. miconis sp. nov., B. amazonense sp. nov., B. pluvialisilvae sp. nov., and B. miconisargentati sp. nov

Ten Bifidobacterium strains, i.e., 6T3, 64T4, 79T10, 80T4, 81T8, 82T1, 82T10, 82T18, 82T24, and 82T25, were isolated from mantled guereza (Colobus guereza), Sumatran orangutan (Pongo abeli), silvery marmoset (Mico argentatus), golden lion tamarin (Leontopithecus rosalia), pied tamarin (Saguinus bicolor), and common pheasant (Phaisanus colchinus). Cells are Gram-positive, non-motile, non-sporulating, facultative anaerobic, and fructose 6-phosphate phosphoketolase-positive. Phylogenetic analyses based on the core genome sequences revealed that isolated strains exhibit close phylogenetic relatedness with Bifidobacterium genus members belonging to the Bifidobacterium bifidum, Bifidobacterium longum, Bifidobacterium pullorum, and Bifidobacterium tissieri phylogenetic groups. Phenotypic characterization and genotyping based on the genome sequences clearly show that these strains are distinct from each of the type strains of the so far recognized Bifidobacterium species. Thus, B. phasiani sp. nov. (6T3 = LMG 32224^T = DSM 112544^T), B. pongonis sp. nov. (64T4 = LMG 32281^T = DSM 112547^T), B. saguinibicoloris sp. nov. (79T10 = LMG 32232^T = DSM 112543^T), B. colobi sp. nov. (80T4 = LMG 32225^T = DSM 112552^T), B. simiiventris sp. nov. (81T8 = LMG 32226^T = DSM 112549^T), B. santillanense sp. nov. (82T1 = LMG 32284^T = DSM 112550^T), B. miconis sp. nov. (82T10 = LMG 32282^T = DSM 112551^T), B. amazonense sp. nov. (82T18 = LMG 32297^T = DSM 112548^T), pluvialisilvae sp. nov. (82T24 = LMG 32229^T = DSM 112545^T), and B. miconisargentati sp. nov. (82T25 = LMG 32283^T = DSM 112546^T) are proposed as novel Bifidobacterium species.     

更年期综合征人体肠道微生物群落结构研究

目的定性定量检测更年期综合征个体肠道微生物群落,探讨该状态中的人群肠道内微生态平衡状态及其特点,从而为研究更年期综合征人群的防治新策略提供数据资料。方法设患更年期综合征妇女研究组和相近年龄同性别的健康妇女对照组,采用光冈法检测相关肠道菌群(双歧杆菌属、乳杆菌属、类杆菌属、产气荚膜梭菌、消化链球菌属、肠杆菌科、肠球菌属及酵母菌)的菌群值,同时计算和比较双歧杆菌属细菌数量与肠杆菌科细菌数量的对数值比值(B/E值)。结果与相似年龄同性别的健康人群对照组比较,更年期综合征人群研究组肠道双歧杆菌数量显著降低(P0.01);B/E值较显著减少(P0.01);肠杆菌科细菌、消化链球菌、肠球菌数量显著增加(P0.01,P0.01,P0.05)。结论更年期综合征人群肠道双歧杆菌数量显著减少,肠杆菌科及肠球菌细菌数量显著增加,益生菌群与肠杆菌科结构发生改变,可能更年期综合征人群由于神经内分泌失调等健康状态的下降,引起肠道有益菌群与腐败菌比例发生变化,从而引起肠道微生态失调。     

双歧杆菌与消化系统疾病的关系

消化系统疾病指的是组成消化道和消化腺的消化器官发生不同程度的病变,具有病因繁杂、病种多样和发病率高等特征,而传统的药物治疗和内镜治疗方法存在安全性较低和副作用大等缺陷,因此采用高效安全的措施来治疗消化系统疾病具有重要意义。双歧杆菌是一类革兰阳性厌氧益生菌,存在于人体消化系统内,其作用主要包括维持正常的微生物群落、抵抗致病菌入侵和增强宿主的免疫调节等。本文对双歧杆菌与消化系统疾病的关系进行了综述,包括双歧杆菌的生物学特性、其对不同类型消化系统疾病的影响、临床应用以及防治机制。     

粪便中双歧杆菌和大肠杆菌含量对肝癌患者预后的预测价值分析

摘要 目的：探讨与分析粪便中双歧杆菌和大肠杆菌含量对肝癌患者预后的预测价值。方法：研究时间为2016年12月到2019年12月,采用回顾性研究方法,选择在本院重症监护病房(Intensive Care Unit,ICU)诊治的肝癌患者78例作为研究对象,检测粪便中双歧杆菌和大肠杆菌含量,调查患者的预后并进行预测价值分析。结果：在78例患者中,死亡18例,死亡率为23.1 %。存活组与死亡组的性别、年龄、体重指数、白细胞(white blood cell,WBC)、血小板(Platelets,PLT)计数计数等对比差异无统计学意义(P>0.05),两组的急性生理学及慢性健康状况评分系统(acute physiology andchronic health evaluation scoring system,APACHE Ⅱ)评分、临床分期等对比差异有统计学意义(P<0.05),死亡组的血清甲胎蛋白(?琢-fetoprotein,AFP)值显著高于存活组(P<0.05)。死亡组的双歧杆菌含量与双歧杆菌/大肠杆菌比值低于存活组,大肠杆菌含量高于存活组,对比差异都有统计学意义(P<0.05)。直线相关分析显示患者预后死亡与双歧杆菌/大肠杆菌比值、AFP、APACHE Ⅱ评分、临床分期有相关性(P<0.05)。双歧杆菌/大肠杆菌比值对肝癌患者预后死亡的预测ROC曲线下总面积为0.865。结论：肝癌患者预后死亡患者多伴随有粪便中菌群失衡状况,粪便中双歧杆菌和大肠杆菌含量能很好预测肝癌患者的预后。     

应用real-timePCR法快速定量人类粪便中双歧杆菌的研究

目的建立快速、准确从粪便标本中定量双歧杆菌的RT—PCR技术。方法传统培养定量法,普通PCR定量法,real—timePCR比较测量。结果（I）粪便标本前处理采取简单的离心和清洗、稀释步骤能去除粪便标本中的抑制物,实现不提取DNA直接进行PCR、real—time定量粪便中双歧杆菌。（2）本实验建立的PCR方法直接半定量粪便双歧杆菌技术在双歧杆菌值介于10^3～10^7CFU／ml时具有较好的分辨率,粪便标本普通PCR得理论菌数与培养得菌数值之间差异无显著性（P〉0．05）;real-timePCR直接定量双歧杆菌技术在双歧杆菌值介于10^1-10^7CFU／ml时具有较好的分辨率,粪便标本RT—PCR得理论菌数与培养得菌数值之间差异无显著性（P〉0．05）。结论利用PCR、real—timePCR直接半定量和定量粪便中的双歧杆菌可行。