Amelioration of dextran sodium sulphate-induced colitis in mice by treatment with Lactobacillus rhamnosus and Lactobacillus reuteri:intraspecific and interspecific patterns

Lactobacillus rhamnosus(Rh)and Lactobacillus reuteri(Re)are well-known probiotic species in inflammatory bowel disease(IBD)research.The variations between these species’efficacy against colitis,and their model of action in this regard,are intriguing and enable treatment to be individually tailored to patients.In this study,four strains each of Rh and Re were isolated from fecal samples and their draft genomes were sequenced.The anti-colitis activities of both strains involved various aspects of intestinal immune,physical,chemical,and biological barrier function.Strikingly,the tested strains exhibited considerable interspecies and intraspecies specificity in colitis amelioration.Rh strains significantly outperformed Re strains in terms of short-chain fatty acid synthesis.Nevertheless,Re strains were more effective than Rh strains in inhibiting production of inflammatory factors;promoting production of intestinal mucus,antimicrobial peptides,and tight junction proteins;and supporting the stem cell compartment.This accounts for the anti-colitis outcomes of Re strains being superior to those of Rh strains.In addition,the effective Rh and Re strains were found to express high concentrations of specific carbohydrate metabolism-and prophage-related genes,respectively.Taken together,the results of this study could assist researchers in developing effective therapies for IBD.

Lactobacillus reuteri PYR8亚油酸异构酶基因在毕赤酵母中的表达

以Lactobacillus reuteriPYR8菌株基因组DNA为模板,利用PCR方法扩增出亚油酸异构酶(linoleate isomerase,LI)基因,将其克隆至酵母表达载体pPIC9K中,电转化至毕赤酵母GS115中.重组菌株GS115/pPIC9K-LI经1%甲醇诱导后,SDS-PAGE电泳表明该基因在酵母中得到表达,即分子量约为67 kD的重组LI蛋白.经SP-Sepharose Fast Flow阳离子交换层析、Phenyl Sepharose Fast Flow疏水层析纯化获得了纯度为95%的重组LI蛋白样品.气相色谱分析表明,纯化的重组LI具有亚油酸异构酶的活性,酶的比活力为6.8 U?mg-1.

Lactobacillus reuteri IMAU10240增殖培养基及高密度培养工艺优化

Lactobacillus reuteri IMAU10240(L.reuteri IMAU10240)是一株具有潜在益生特性的乳酸菌,为实现产业化应用,对其培养工艺进行优化以提高其活菌数。本研究以MRS培养基为基础,通过单因素筛选试验、正交试验和响应面优化试验对该菌株的培养基以及培养条件进行优化。通过实验确定L.reuteri IMAU10240最适培养基:蔗糖100.00 g/L,大豆蛋白胨13.25 g/L,酵母粉8.84 g/L,酵母蛋白胨13.25 g/L,Na_2HPO_4 19.85 g/L,柠檬酸2.58 g/L,MnSO_4·5H_2O 0.12 g/L,MgSO_4·7H_2O 0.40 g/L,甘油2.76 g/L,吐温-80 1.00 g/L,L-半胱氨酸盐酸盐0.50 g/L。初始pH 6.5,通入氮气37℃恒pH 5.5培养7~8 h。利用优化好的配方工艺进行5 L/50 L/200 L发酵罐的小试及中试试验,验证L.reuteri IMAU10240的发酵工艺,活菌数为7.57×10~9 CFU/mL,冻干菌粉活菌数为2.59×10^(11) CFU/g,可以进行生产验证。

热激处理罗伊氏乳杆菌(Lactobacillus reuteri)增强其抗逆性的研究

为了研究热激对益生菌抗逆性的影响,本研究以罗伊氏乳杆菌(Lactobacillus reuteri)为实验对象,以存活率、抗性基因表达为指标,采用平板计数法研究了热激处理对罗伊氏乳杆菌在后续高温和高盐逆境下存活率提高的效果,并用q PCR方法检测基因表达水平。结果表明:热激预处理(40℃,30 min)罗伊氏乳杆菌之后,能显著(p<0.05)提高其在后续高温(45、48、51℃),高盐(0.1%、0.3%、0.7%Na Cl,m/v)以及氧化逆境(H2O2,0.3、0.6、1.2 mmol/L)下的存活率。此外,热激预处理(40℃,30 min)还能显著(p<0.05)提高巯基过氧化物酶(thiol peroxidase)和抗氧化蛋白(peroxiredoxin)的转录表达水平。说明热激处理通过提高罗伊氏乳杆菌抗逆基因的表达,增强其对于后续逆境的抗性。该研究结果为益生菌的规模化应用提供了理论依据。

Helicobacter pylori eradication: Sequential therapy and Lactobacillus reuteri supplementation

AIM:To evaluate the role of sequential therapy and Lactobacillus reuteri (L. reuteri ) supplementation, in the eradication treatment of Helicobacter pylori (H. pylori ). METHODS:H. pylori infection was diagnosed in 90 adult dyspeptic patients. Patients were excluded if previously treated for H. pylori infection or if they were taking a proton pump inhibitor (PPI), H2-receptor antagonist or antibiotics. Patients were assigned to receive one of the following therapies:(1) 7-d triple therapy (PPI plus clarithromycin and amoxicillin or metronidazole) plus L. reuteri supplementation dur- ing antibiotic treatment; (2) 7-d triple therapy plus L. reuteri supplementation after antibiotic treatment; (3) sequential regimen (5-d PPI plus amoxicillin therapy followed by a 5-d PPI, clarithromycin and tinidazole) plus L. reuteri supplementation during antibiotic treatment; and (4) sequential regimen plus L. reuteri supplementation after antibiotic treatment. Successful eradication therapy was defined as a negative urea breath test at least 4 wk following treatment. RESULTS:Ninety adult dyspeptic patients were en- rolled, and 83 (30 male, 53 female; mean age 57 ± 13 years) completed the study. Nineteen patients were administered a 7-d triple treatment:11 with L. reuteri supplementation during and 8 after therapy. Sixty-four patients were administered a sequential regimen:32 with L. reuteri supplementation during and 32 after therapy. The eradication rate was significantly higher in the sequential group compared with the 7-d triple regimen (88% vs 63%, P = 0.01). No difference was found between two types of PPI. No difference in erad- ication rates was observed between patients submitted to L. reuteri supplementation during or after antibiotic treatment. Compliance with therapy was excellent in all patients. No difference in adverse effects was observed between the different antibiotic treatments and between patients submitted to L. reuteri supplementation during and after antibiotic treatment. There was a low incidence of adverse effects in all groups of patients with sequential therapy, probably due to the presence of the L. reuteri supplementation. CONCLUSION:The sequential treatment regimen achieved a significantly higher eradication rate of H. pylori compared with standard 7-d regimen. L. reuteri supplementation could reduce the frequency and the intensity of antibiotic-associated side-effects.

Effects of drinking water supplementation with Lactobacillus reuteri,and a mixture of reuterin and microcin J25 on the growth performance,caecal microbiota and selected metabolites of broiler chickens

Background:Since the overuse of antibiotics in animal production has led to a selection of antibiotic-resistant pathogens that affect humans and animals as well.Scientists are therefore searching for novel natural alternatives to antibiotics.In this study Lactobacillus reuteri and a combination of reuterin and microcin J25(RJ)were evaluated as promoters of growth and modulators of the cecal microbiota and metabolite profiles in broiler chickens.Oneday-old Cobb 500 male broilers were distributed to 8 treatments:negative control(without antibiotic),positive control(bacitracin),three concentrations of RJ and three doses of L.reuteri plus glycerol.The birds(2176,34 per pen,8 pens per treatment)were reared for 35 d.Results:The body weight of the bacitracin and 5 mmol/L reuterin combined with 0.08μmol/L microcin J25(10RJ)treatment group was significantly higher than that of the negative control group(P<0.05).L.reuteri had no significant effect on broiler growth.MiSeq high-throughput sequencing of 16S rRNA showed clustering of cecal microbial operational taxonomic unit diversity according to treatment.The influence of bacitracin and 10RJ on bacterial community overall structure was similar.They promoted Ruminococcaceae,Lachnospiraceae and Lactobacillaceae,increased the relative abundance of Faecalibacterium and decreased the abundance of Bacteroides and Alistipes,while the negative control condition favored Bacteroidaceae and Rikenellaceae.Furthermore,10RJ increased the concentration of short-chain fatty acid in the cecum and changed the metabolome overall.Conclusions:These overall suggest that 10RJ can promote a host-friendly gut environment by changing the cecal microbiome and metabolome.This combination of natural antimicrobial agents in the drinking water had a positive effect on broiler growth and may be suitable as an alternative to antibiotic growth promoters.

Effect of Daily Consumption of <i>Lactobacillus reuteri </i>CRL 1098 on Cholesterol Reduction in Hypercholesterolemic Subjects

The effect of daily consumption of a yogurt containing Lactobacillus reuteri CRL 1098 on the lipid profile of hypercholesterolemic subjects was evaluated by performing a prospective, randomized, double-blind, cross-over placebo controlled clinical study. Participants consumed daily a yogurt containing L. reuteri CRL 1098 or a placebo for four weeks, separated by a wash-out period. Total cholesterol, triacylglycerol, high-density (HDL) and low-density (LDL) lipoprotein levels were assessed at the beginning and at the end of each period. We found a statistically significant reduction of total (–7.86 g/dl) and LDL (–7.02 g/dl) cholesterol in absolute changes (before-after) as well as a decreasing trend in the group receiving the yogurt containing L. reuteri with respect to the placebo group, without detecting changes in HDL-cholesterol and triacylglycerol levels. Our results suggest that low amounts of yogurt (125 g/day) and low doses of the CRL 1098 strain (106 CFU) are sufficient to reduce total and LDL-cholesterol levels in hypercholesterolemic subjects.

Molecular and Probiotic Characterizations of <i>Lactobacillus reuteri</i>DSM 12246 and Impact of pH on Biomass and Metabolic Profile in Batch-Culture

Lactobacillus reuteri is a powerful probiotic and adjunct functional culture candidate received a lot of scientific attention as it is one of the few endogenous “Lactobacillus” species found in the gastrointestinal tract of vertebrates, including humans, rats, pigs and chicken. The organism has been widely utilized as a probiotic in humans and animals for many years. In the present work L. reuteri DSM 12243;a high reuteri producer strain was molecularly characterized by 16SrRNA and RAPD analyses further, the probiotic properties including acid resistance, bile tolerance, adhesion to epithelial gastric cells, and antibiotic susceptibility were also assessed. Furthermore, the effect of pH on biomass production and metabolic profile of L. reuteri DSM 12246 in batch-culture was studied. The L. reuteri DSM 12246 showed a high similarity with L. reuteri strain I49 KR 36477 (100%) and type strain ATCC 55730 (99% of identity). The strain adhered well to CaCO2 cells and showed to be a highly resistance to acid juice (pH 3.0), with 0.7 log10 cfu/ml reduction in count after 60 min exposition. There is no significant change in the cell count after exposure to bile salts. In batch-cultures, at low pH values both glucose consumption and metabolites were low while the production of lactic acid was noticeable. Maximum biomass was reached at pH 5.5, with growth rate of μ = 0.641/h. The switch in pH values from 3.7 to 6.7 resulted in raising of glucose depletion as well as in the yield of acetate and ethanol. It is concluded that L. reuteri DSM 12246 was deemed as a successful candidate to be used as potential probiotic.

滇黄精总多糖及水提物对罗伊氏乳杆菌1.2838群体感应信号分子AI-2的影响

通过探究在不同胃肠道胁迫条件下,药食同源中药材滇黄精总多糖和水提物对罗伊氏乳杆菌1.2838群体感应信号分子自诱导物-2(autoinducers-2,AI-2)的影响,分析其对罗伊氏乳杆菌1.2838的保护作用。将活化的罗伊氏乳杆菌1.2838与滇黄精总多糖和水提物分别进行共孵育至其OD600 nm为0.6~0.8,将处理后的益生菌在胃肠道胁迫条件下培养1 h~3 h后检测AI-2的生成量。结果表明,滇黄精总多糖和水提物在一定程度上能提高罗伊氏乳杆菌1.2838在胃肠道胁迫条件下AI-2的生成量,滇黄精水提物对罗伊氏乳杆菌1.2838的保护作用优于滇黄精总多糖。

以高嘌呤饮食评估罗伊氏乳杆菌Lactobacillus reuteri GKR1之降尿酸效果

近年来,高尿酸血症的盛行率居高不下,高嘌呤饮食为引起高尿酸血症之重要因素,高尿酸血症会增加罹患心血管疾病、糖尿病、肾脏病功能异常、高血压等疾病的机率,而降尿酸药物具有副作用,因此需开发替代治疗之策略。本试验先以体外试验筛选具有降尿酸潜力菌株,发现效果最佳菌株为Lactobacillus reuteri GKR1,再以高嘌呤饮食饲料评估Lactobacillus reuteri GKR1于小鼠之降尿酸效果,试验将ICR小鼠分为5组:正常对照组、负对照组、阳性对照组、低剂量GKR1组及高剂量GKR1组,连续14天将试验物质经管喂投予小鼠,在试验第7及第14天收集各组小鼠血清,分析尿酸(Uric acid)、尿素氮(BUN)与肌肝酸(Creatinine)含量,在试验第14天采集小鼠肝脏分析黄嘌呤氧化酶活性。实验结果显示,低、高剂量组GKR1可降低血清中尿酸、尿素氮含量,高剂量GKR1组显着减少肝脏中黄嘌呤氧化酶活性,综合以上结果,GKR1具有开发为降尿酸保健食品之潜力。

鸡源高黏附性乳酸菌的筛选及其发酵条件优化

研究旨在筛选获得高黏附性、益生特性优良、具有高活性的鸡源乳酸菌,为鸡源益生菌制剂的开发奠定基础。从健康散养鸡肠道中分离宿主源乳酸菌,对分离菌株的表面疏水性、自聚力、共聚力等表面黏附特性及体外黏附作用进行研究,筛选高黏附性乳酸菌,评价其益生特性。利用响应面法对高黏附性乳酸菌发酵条件中显著影响因素进行优化,获得其最佳的发酵条件。结果显示,从鸡肠道中分离出1株罗伊氏乳杆菌L6,体外黏附效率可达29.47%,黏附效率显著高于其他乳酸菌分离株,在模拟胃肠液中存活率可达80.11%,对致病性大肠杆菌1.505具有显著的抑菌效果(P<0.05)。对罗伊氏乳杆菌L6发酵条件优化,获得最佳的发酵条件为:初始pH 6.73、酵母浸粉添加量6.63 g/L,葡萄糖添加量28.85 g/L,优化后其有效活菌数量可达8.56×10^(9) CFU/mL。从鸡肠道分离获得的高黏附性的宿主源性乳酸菌罗伊氏乳杆菌L6具有较好的定植优势与益生性能,有助于其在宿主内发挥益生作用。

罗伊氏乳杆活菌和热灭活菌对小鼠抑郁样行为的影响及作用机制

为了探究罗伊氏乳杆活菌与灭活菌对小鼠肠道菌群失衡引起的抑郁样行为的作用及作用机制,采用头孢曲松钠(Ceftriaxone sodium,CRO)处理构建肠道菌群失衡小鼠抑郁模型,并用罗伊氏乳杆活菌(Live Lactobacillus reuteri,Live LR)和热灭活菌(Heat-killed Lactobacillus reuteri,HK LR)进行干预。采用ELISA试剂盒测定5-羟色胺、5-羟基吲哚乙酸、色氨酸和皮质酮质量浓度;通过H&E染色观察结肠组织形态;通过高通量测序和生物信息学分析对肠道微生物组进行分析。结果表明:Live LR和HK LR干预缓解了小鼠抑郁样行为,修复了CRO引起的肠道菌群失调,并减少了结肠组织炎细胞浸润。两种益生菌的作用机制存在差异,Live LR侧重于肠道菌群的重塑,而HK LR则通过其代谢产物直接发挥抗炎作用。

罗伊氏乳酸菌外囊泡对LPS诱导的奶牛子宫内膜上皮细胞炎症的影响

该文拟研究罗伊氏乳酸菌外囊泡对脂多糖诱导的奶牛子宫内膜炎上皮细胞的影响。超速离心法提取乳酸菌外囊泡并观察其表征图像;使用PKH-26标记外囊泡,检测BEEC对其的摄入;使用实时荧光定量PCR、蛋白质免疫印迹和酶联免疫吸附试验,检测外囊泡对LPS诱导的BEEC炎症反应中PCNA、TNF-α、IL-1β、IL-6、IL-10、NF-κB水平的影响。结果显示,BEEC能摄入乳酸菌外囊泡,同时外囊泡能够促进BEEC的增殖;在LPS诱导的BEEC细胞炎症中,外囊泡能够有效抑制TNF-α、IL-β、IL-6的释放和NF-κB的磷酸化水平,并且能够促进IL-10的分泌和释放。罗伊氏乳酸菌外囊泡能够通过调节炎性因子的释放,进而缓解BEEC细胞的炎症反应。

罗伊氏乳杆菌提取物对牙周炎症微环境中巨噬细胞功能及牙槽骨吸收的影响研究

目的:探讨罗伊氏乳杆菌超声提取物对牙周炎微环境中巨噬细胞功能的影响。方法:体外筛选罗伊氏乳杆菌提取物干预小鼠巨噬细胞系RAW264.7的最佳浓度。随后将细胞分为PBS对照组、LPS组和LPS+罗伊氏乳杆菌提取物组,利用real-time PCR、ELISA和免疫荧光染色检测各组细胞的炎性巨噬细胞标志物的表达水平,利用Western blot对其机制进行探讨。体内建立大鼠丝线结扎牙周炎模型,观察罗伊氏乳杆菌提取物局部注射对于牙周骨组织破坏的治疗作用。结果:体外结果表明50μg/mL的罗伊氏乳杆菌提取物通过抑制NF-κB信号通路p-IκK和p-NF-κB蛋白的磷酸化(P<0.01),下调了LPS诱导的炎性巨噬细胞inos(P<0.05),Il1b(P<0.01)的基因表达水平,并抑制了LPS诱导的巨噬细胞TNF-α的细胞因子表达(P<0.05)。体内结果表明,罗伊氏乳杆菌提取物通过抑制牙周局部炎症进而下调破骨细胞的数量(P<0.01)和阳性面积(P<0.05),相较于牙周炎造成的骨吸收(P<0.01),罗伊氏乳杆菌提取物治疗减少了牙槽骨的吸收高度(P<0.05)。结论:罗伊氏乳杆菌提取物抑制炎症微环境中巨噬细胞的炎症因子表达,对牙周炎组织中牙槽骨的吸收破坏起到了保护作用。

产叶酸菌株的筛选及产量的优化

本研究分别从母乳、婴儿粪便、乳制品和酸肉中筛选叶酸生产菌株,并通过培养基优化、代谢途径研究等方法提高叶酸的产量。结果表明,在39株产叶酸菌株中得到4株高产菌株,分别为鼠李糖乳杆菌B2-14(39.56 ng/mL)、双歧杆菌D020(32.56 ng/mL)、罗伊氏乳杆菌B1-28(60.72 ng/mL)、格式乳杆菌F020(61.22 ng/mL)。通过优化培养基条件,叶酸产量可提高50%~70%。在经过条件优化的牛乳培养基中培养,叶酸产量可提高6~10倍。其中,菌株B1-28在牛乳培养基培养后产量达910 ng/mL。分析产叶酸路径的一些指标及相关代谢基因,探究叶酸合成途径指标的变化及其机理,从而研制出有利于人群叶酸摄入的乳制品。

不同猪源受体菌表达猪流行性腹泻病毒保护性抗原S1诱导免疫应答的比较研究

旨在比较猪源副干酪乳酪杆菌(Lacticaseibacillus paracasei)、罗伊氏黏液乳杆菌(Limosilactobacillus reuteri)、约氏乳杆菌(Lactobacillus johnsonii)作为口服疫苗载体,表达外源蛋白刺激仔猪产生免疫能力的强弱,以期选取合适乳酸菌作为受体菌载体。本研究首先体外鉴定表达PEDV S1蛋白的重组猪源副干酪乳酪杆菌(pPG-T7g10-S1/L.paracasei 27-2)、猪源罗伊氏黏液乳杆菌(pPG-T7g10-S1/L.reuteri J31)、猪源约氏乳酸杆菌(pPG-T7g10-S1/L.johnsonii 6332)的耐酸耐胆盐能力,考察3株重组菌的抗逆性。结果表明,3株重组菌均能够耐受酸和胆盐环境,且与其野生型菌株没有显著差异。接下来为比较3株重组菌的免疫效果,口服免疫初生仔猪后,利用间接ELISA和中和试验检测仔猪产生的特异性抗体水平及其中和活性;并测定免疫后仔猪血清和肠黏膜中各细胞因子水平。结果显示,口服免疫后,与对照组相比,3株免疫组仔猪血清IgG抗体和鼻拭子、肛拭子、肠黏液中SIgA抗体水平均显著升高,且可持续至第28天左右,其中pPG-T7g10-S1/L.paracasei 27-2组诱导产生的抗体水平显著高于其他两组免疫组(P<0.05);仔猪产生特异性的IgG和SIgA对PEDV均具有中和活性。仔猪血清中细胞因子IFN-γ、IL-2、IL-4、IL-10水平和对照组相比显著升高(P<0.05),但3株重组菌组间细胞因子水平未见明显差异;仔猪空肠黏膜中细胞因子IFN-γ、IL-2、IL-4、IL-5、IL-6、IL-17、IL-21、TGF-β、APRIL和BALL水平与对照组相比有所升高,且pPG-T7g10-S1/L.paracasei 27-2组IL-4、IL-5、IL-6、TGF-β、IL-17、IL-21和BALL相比其他组显著升高(P<0.05)。综上所述,本研究分别将质粒组成型表达PEDV主要保护性抗原S1的重组猪源副干酪乳酪杆菌、猪源罗伊氏黏液乳杆菌和猪源约氏乳酸杆菌口服免疫仔猪,结果显示能够刺激机体产生针对PEDV的黏膜免疫、体液免疫和细胞免疫,且相较于其他2株重组菌,重组猪源副干酪乳酪杆菌pPG-T7g10-S1/L.paracasei 27-2的口服免疫效果最好。该试验结果为构建更为有效的乳酸菌口服疫苗提供了科学数据。

牛源罗伊氏乳杆菌对产肠毒素大肠杆菌攻毒小鼠生长性能、免疫性能、抗氧化能力及肠道健康的影响

本试验旨在研究牛源罗伊氏乳杆菌对产肠毒素大肠杆菌(ETEC)攻毒小鼠生长性能、脏器指数、免疫性能、抗氧化能力、肠道屏障功能及肠道组织形态结构的影响。试验选取4周龄、初始体重相近的无特定病原体(SPF)级ICR雄性小鼠40只,随机分为4组,即对照组、攻毒组、试验Ⅰ组和试验Ⅱ组,每组10只。小鼠适应性饲养7 d后开始正式试验,正试期22 d。在正式试验第1~17天,对照组和攻毒组小鼠饲喂基础饲粮,每天灌胃0.2 mL的生理盐水;试验Ⅰ组和试验Ⅱ组小鼠饲喂基础饲粮,每天分别灌胃1×10^(8)和1×10^(9)CFU/mL的牛源罗伊氏乳杆菌菌悬液0.2 mL;在正式试验第18~22天,对照组小鼠每天灌胃0.2 mL的生理盐水,其他3组小鼠每天灌胃5×10^(9)CFU/mL的ETEC菌悬液0.2 mL进行攻毒。结果显示:1)ETEC攻毒后,与对照组相比,攻毒组小鼠平均日增重显著降低(P<0.05);试验Ⅰ组和试验Ⅱ组小鼠的平均日增重则无显著变化(P>0.05)。2)ETEC攻毒后,与对照组相比,攻毒组小鼠胸腺指数显著降低(P<0.05),心脏指数显著升高(P<0.05);试验Ⅰ组和试验Ⅱ组小鼠的胸腺指数和心脏指数则无显著变化(P>0.05)。3)ETEC攻毒后,试验Ⅱ组小鼠血清中免疫球蛋白A、免疫球蛋白G、免疫球蛋白M和白细胞介素-10含量显著高于攻毒组(P<0.05),白细胞介素-6、肿瘤坏死因子-α和白细胞介素-1β含量显著低于攻毒组(P<0.05)。4)ETEC攻毒后,试验Ⅰ组和试验Ⅱ组小鼠血清中谷胱甘肽过氧化物酶活性显著高于攻毒组(P<0.05),丙二醛含量显著低于攻毒组(P<0.05);此外,试验Ⅱ组小鼠血清中超氧化物歧化酶活性也显著高于攻毒组(P<0.05)。5)ETEC攻毒后,与攻毒组相比,试验Ⅰ组和试验Ⅱ组小鼠血清中二胺氧化酶活性显著降低(P<0.05),且试验Ⅱ组小鼠血清中D-乳酸和内毒素含量显著降低(P<0.05)。6)与对照组相比,攻毒组小鼠空肠绒毛高度显著降低(P<0.05),试验Ⅰ组和试验Ⅱ组小鼠空肠绒毛高度则无显著变化(P>0.05)。综上所述,牛源罗伊氏乳杆菌能够缓解ETEC攻毒引起的小鼠体重下降,提高机体免疫性能和抗氧化能力,减轻ETEC感染导致的脏器及肠道损伤。

耐热型罗伊氏乳杆菌液态微胶囊的制备及其体外模拟消化特性

为了提高罗伊氏乳杆菌的耐热性,该研究以麦芽糊精与磷脂作为复合壁材,对其进行包埋处理形成罗伊氏乳杆菌液态微胶囊。结果表明:随磷脂、麦芽糊精浓度增加及乳化时间的延长,微胶囊的包埋率、EAI、ESI及电位绝对值呈先增加后减小的趋势(P<0.05),平均粒径呈先减小后增加的趋势(P<0.05)。通过响应面设计得到该微胶囊最佳制取工艺:磷脂添加量14.83%(m/m),麦芽糊精溶液质量分数15%(m/m),乳化时间86.39 min,包埋率为99.11%。罗伊氏乳杆菌微胶囊热处理后其活菌数明显提高(P<0.05)。体外模拟消化试验显示,胃消化阶段,肠消化阶段活菌数随时间逐渐增多(P<0.05),2 h后微胶囊活菌数达到1.85×10^(8)CFU/mL。综上,由麦芽糊精、磷脂复合壁材制备的罗伊氏乳杆菌液态微胶囊包埋效果良好,提高了罗伊氏乳杆菌的耐热性和胃肠道存活率。研究结果为罗伊斯乳杆菌微胶囊的生产应用提供理论依据。

益生菌饼干的3D打印制备及研究

目前对罗伊氏乳杆菌(Lactobacillus reuteri,LR)的封装研究以及3D打印后可直接食用的益生菌饼干研究较少,该文介绍了一种制备LR封装颗粒(LR-encapsulated particle,LEP)的方法,并将其添加到小麦粉中,制备可直接食用的饼干面团,再对饼干面团进行3D打印,验证其3D打印适应性并对面团的物料特性进行了评估。结果表明,LEP的封装效率为(70.3±1.21)%~(83.5±1.25)%,且LEP外观呈球状。当LEP中LR与蛋清添加量以5∶10(g∶g)添加到面团中时,面团储存模量G′和损失模量G″均达到最大值,说明加入该比例LEP的面团具有较高的机械强度。当打印速度15 mm/s、打印压力350 kPa,使用直径1 mm的打印喷嘴,添加3种不同比例的面团均表现出良好的3D打印适应性。体外模拟消化结果表明,5/10-LEP,7/10-LEP以及9/10-LEP均可在肠道中发挥益生菌作用。该文完成了以罗伊氏乳杆菌为原料的3D打印食品制备,为益生菌3D打印食品的发展提供了参考。

基于BPANN-GA算法的罗伊氏乳杆菌富硒发酵条件优化

为优化罗伊氏乳杆菌(Lactobacillus reuteri)的富硒发酵条件,采用反向传播人工神经网络结合遗传算法(back propagation artificial neural network combined with genetic algorithm,BPANN-GA)来优化罗伊氏乳杆菌的富硒发酵参数。选取培养温度、培养基pH值、硒质量浓度和加入硒的时间为输入变量,以菌体干重为输出变量建立神经网络模型,该模型的拟合优度达到了99.27%。模型建好以后,通过遗传算法对最佳培养参数寻优,选取符合设备条件的近似值进行实验验证,最终确定以菌体干重为目标的最佳培养参数是:温度为36.74℃、培养基pH值为6.56、硒质量浓度为1.43μg/mL、加入硒的时间为培养开始后的5.58 h,在该条件下获得的菌体干重为(13.15±0.03)g/L,其硒转化率为(20.23±0.39)%。且该条件下培养的罗伊氏乳杆菌在模拟胃液中3 h后的存活率为(89.40±0.42)%,在模拟肠液中3、6 h的存活率分别为(96.70±0.39)%、(95.80±0.25)%,具有较高的耐受性。该方法能够实现罗伊氏乳杆菌的富硒发酵条件优化,为相关研究提供理论基础。