Demonstration of safety characteristics and effects on gut microbiota of Lactobacillus gasseri HMV18

Human normal flora is a source of probiotics.The safety characteristics of a specific isolate determine its application in foods or drugs.The food-borne-pathogen antagonist strain Lactobacillus gasseri HMV18 is one of the isolates from normal human flora.In this work,we assessed the in vitro pH tolerance,bile tolerance,biogenic amine production,mucin utilization,and safety of in vivo administration to mice to evaluate general health,organ-body weight index,organ histopathological change,whether L.gasseri HMV18 can colonize in the gut or modulate the gut microbiota after oral administration.The results suggest that L.gasseri HMV18 can tolerate pH 3 for 2 h,3%bile for 3 h,biogenic amine negative,mucin usage negative,does not encode verified toxins,and cause no visible change in mice's organs.L.gasseri HMV18 might not colonize in mice's gut,but can significantly affect the structure of gut microbiota.A bibliographical survey suggested that there were as few as 8 opportunistic infection cases from 1984 to 2022 and that the possibility for L.gasseri to cause infection is relatively low.Therefore,this work provides a basis for the foods or drugs application of L.gasseri HMV18 and gives a map of experiments for the safety assessment of probiotics.

高产胆盐水解酶乳杆菌的筛选及对新生大鼠黄疸的防治作用

为筛选高产胆盐水解酶的乳杆菌,探究其对新生儿黄疸的防治作用。采用添加了25 U/mL制霉菌素的LBS选择性培养基,从健康新生儿粪便和母乳中筛选乳杆菌并鉴定种类;以鼠李糖乳杆菌LGG为阳性对照,体外评估菌株的益生菌特性;利用盐酸苯肼诱导新生SD大鼠黄疸模型,通过分析血清胆红素水平和肝脏组织的损伤情况,以及肝脏炎症因子、核转录因子的相对表达水平,探究高产胆盐水解酶乳杆菌对新生大鼠黄疸的防治作用及机制。结果表明,来自婴儿粪便的格氏乳杆菌FWJL-5在体外具良好的益生特性,并且产胆盐水解酶能力优于LGG,能够显著缓解新生大鼠胆红素水平升高、肝脏组织肿胀和溶血症状,减少肝脏损伤中肝酶的释放,抑制促炎因子的分泌,促进UGt1A1和上游核转录因子孕烷X受体(pregnane X receptor,pXR)、法尼醇X受体(farnesol X receptor,FXR)的表达。综上所述,婴儿粪便来源的格氏乳杆菌FWJL-5可通过上调核受体FXR/pXR促进UGt1A1表达以调节肝脏胆红素代谢,从而减轻新生大鼠黄疸症状,本研究可为格氏乳杆菌防治新生儿黄疸提供新思路。

产不同细菌素的格氏乳杆菌对小鼠肠道微生态的影响

目前已发现格氏乳杆菌(Lactobacillus gasseri,L.gasseri)产生的多种细菌素对多种致病菌具有抑制作用,但有关细菌素对格氏乳杆菌和宿主肠道微生态之间关系的研究较少。为探究产不同细菌素的格氏乳杆菌及其对小鼠肠道微生态的影响,作者通过细菌素操纵子预测、抑菌试验以及液相色谱-质谱联用法证明了格氏乳杆菌FNMGHLBE6L1、FNMGHLBE20L5、FHNFQ16L5可产不同细菌素,之后通过动物试验探究不同格氏乳杆菌对小鼠肠道微生态的影响。结果表明,3株格氏乳杆菌均对小鼠肠道菌群的多样性及菌群结构产生了显著影响;且格氏乳杆菌显著降低了小鼠结肠中白介素-1β的水平。综上,产不同细菌素的格氏乳杆菌可对宿主肠道菌群产生显著影响,且菌株间的差异与所产细菌素存在相关性。该研究为探究产不同细菌素的格氏乳杆菌与肠道菌群之间的关联提供了依据。

Effects of Probiotic Lactobacillus gasseri Strains of Breast-Fed Infant in a Murine Model

The ingestion of probiotic lactic acid bacteria has been evaluated and noted that it has an effect on the balance of desirable microbiota in the gastrointestinal tract. Lactobacillus gasseri demonstrates good survival in the gastrointestinal tract, and it has been associated with a variety of probiotic activities and roles, including the reduction of fecal mutagenic enzymes, the production of bacteriocins and the stimulation of macrophages immunomodulation. The aim of the study was to evaluate the effects of a pool of L. gasseri strains isolated from the feces of breastfed infants added in the human milk of healthy women. The milk was both pasteurized and unpasteurized, to verify the cell cytotoxicity of macrophages and to quantify the production of immunologic mediators such as IL-4, IL-6, IFN-γ, TNF-α, NO and oxygen intermediary compounds （H2O2）. The administration of raw human milk and pasteurized human milk to infants is a regular, encouraged practice in units of intensive therapy （UITs） and our present investigation verified the beneficial effect of addition of a pool of L. gasseri to pasteurized human milk （PHML）. Our results show that probiotic supplementation helped to maintain cell viability, reduced IL-6 and IFN-γ production and stimulated TNF-α, NO, H2O2, IL-4 production. Nevertheless, the results indicate that the addition of lactobacillus to human milk was not a determinant in the production of TNF-α. L. gasseri added to breast milk did not present a cytotoxic risk, and the addition ofL. gasseri to pasteurized milk of human milk bank would benefit newborns that depend on milk banks for the colonization of more desirable microbiota.

Survivability of freeze-dried probiotic Pediococcus pentosaceus strains GS4,GS17 and Lactobacillus gasseri(ATCC 19992)during storage with commonly used pharmaceutical excipients within a period of 120 days

Objective: To examine the survivability and stability of probiotic strains in presence and absence of pharmaceutical excipients for a long period of time at(4 ± 1)℃.Methods: The survival rates of probiotic strains, Pediococcus pentosaceus GS4(MTCC12683)(NCBI HM044322), GS17(NCBI KJ608061) and Lactobacillus gasseri(ATCC 19992), were evaluated. Probiotic strains were lyophilized individually and in combination of excipients(sorbitol, ascorbic acid, fructose and skim milk). The preparation was monitored for 120 d storing at(4 ± 1)℃. During storage, all the preparations were evaluated for viability and stability of probiotic properties like lactic acid production, antimicrobial effect, water activity, and adherence to epithelial cells.Results: Sorbitol, ascorbic acid and skim milk favoured the viability of freeze-dried cells and sustained probiotic properties during storage. Without excipients(control group),strains showed percentage of survivability not more than 70% while strains with excipients survived for 73%–93% for a long period of time.Conclusions: Commonly used excipients can be considered as a vehicle for delivering active principle in probiotic formulation and for sustaining the viability and stability of probiotic strains for a period of 120 d.

A new Lactobacillus gasseri strain HMV18 inhibits the growth of pathogenic bacteria

To search for a new eco-friendly therapy for infectious disease caused by Escherichia coli,Staphylococcus aureus or Klebsiella oxytoca,we collected the vaginal swabs from healthy women,screened for Lactobacillus and found a strain repressing the growth of pathogenic bacteria.The new isolate was identified as L.gasseri by the colony morphology,Gram staining,biochemical reactions and confirmed by the 16 S rDNA sequencing.The HMV18 strain inhibited the growth of food-borne pathogens such as E.coli,S.aureus and K.oxytoca.The HMV18 strain was sensitive to penicillin,ampicillin,erythromycin,tetracycline and chloramphenicol.The HMV18 strain producedα-hemolysis.Pathological histology of the mice ileum showed that the mucosa,villi,lamina propria and crypt depth remained intact and there was no inflammation or hyperemia in the L.gasseri HMV18 gavaged group.L.gasseri HMV18 could not up-regulate inflammatory cytokines level of plasma.All the results suggested L.gasseri HMV18 is a candidate probiotic to be an additive for food preservation or drug to prevent food-borne diseases.

Effects of Yogurt Containing <i>Lactobacillus gasseri</i>OLL2716 on Autonomic Nerve Activities and Physiological Functions

The purpose of this study was to investigate the effects of yogurt containing Lactobacillus gasseri OLL2716 (LG21) on autonomic nerve activities, peripheral blood flow, skin condition (skin pig-mentations and moisture), saliva s-IgA and examination of quality of life (QOL). 20 healthy female volunteers (yogurt containing LG21 group: 10 people, yogurt containing Bifidobacterium (Bif) group: 10 people) were examined. The subjects ingested 100 g of yogurt twice daily for 4 weeks. Analysis was before and after 4 weeks dosage. By the effects for the autonomic nervous activity, parasympathetic increase was observed in the LG21 yogurt group, but was not significant increase. The LG21 yogurt was significantly increased on the peripheral blood flow. The LG21 yogurt was significantly increased on saliva s-IgA. The LG21 yogurt and Bif yogurt were significantly decrease on skin pigmentation. Also, LG21 yogurt was significantly increased on skin moisture. As a result of QOL questionnaire, incomplete evacuation, lower abdominal fullness, cold extremities and pimply or rough skin improved in LG21 yogurt and Bif yogurt after the administration period. These results suggest that the improvement effects of LG21 yogurt may be related to the activity of the parasympathetic nervous system.

北京分离株Gassericin T基因的克隆、表达及活性检测

目的克隆格氏菌素T基因,在原核细胞中表达,并检测其抑菌活性。方法通过PCR技术,从3株L.gasseri北京分离株中特异性扩增格氏菌素T的成熟肽DNA编码片段(V11/gatA和V441/gatA),经TA克隆和序列测定后,进行同源比较分析。双酶切后的目的片段与表达载体pGEX6P1连接,得到高效融合表达质粒pGEXgatA/V11和pGEXgatA/V441,转化大肠杆菌BL21(DE3)PlysS,IPTG诱导表达,并检测表达产物的抑菌活性。结果目的蛋白以包涵体形式表达,表达量约29%。重组格氏菌素对于金黄色葡萄球菌、铜绿假单胞菌、痢疾志贺氏菌和伤寒沙门氏菌具有明显的抑制生长作用。结论所获得的重组格氏乳杆菌素具有明显的抑菌活性,有望成为新型抗菌素。

加氏乳杆菌的特性与生物学功能及其生产应用

加氏乳杆菌(Lactobacillus gasseri)是一种定居在人类胃肠道、口腔、阴道中的常见微生物,具有多种益生特性,主要因其减肥特性而闻名。目前主要被应用于食品行业,能够降低金黄色葡萄球菌等病原体在肉产品中的生长,还能作为人用益生菌改善人体胃肠道功能。文章综述了加氏乳杆菌的相关生物学功能及其在家禽生产上的应用及前景,以期为加氏乳杆菌复合制剂保健、治疗疾病等方面提供参考。

格氏乳杆菌GU-G23高密度培养因子多维度优化及其验证

为提高具有益生特性格氏乳杆菌GU-G23的生物量,获取其高密度培养因子,该研究首先通过单因素实验和Plackett-Burman实验筛选出该菌株主要的生长营养因子为鱼蛋白胨、胰蛋白胨、柠檬酸三铵。以响应面实验设计组合作为机器模型训练样本,采用随机森林回归(Random Forest Regression,RFR)和径向基神经网络(Radial Basis Function Neural Network,RBF)模型对其培养基配方进行预测。以决定系数(R-squared,R^(2))、平均绝对误差(Mean Absolute Deviation,MAE)、均方误差(Mean-Square Error,MSE)和平均绝对百分误差(Mean Absolute Percentage Error,MAPE)作为模型评价指标,比较认为RBF在该研究中具有更好的预测性能。随后选择RBF神经网络和遗传算法(Genetic Algorithm,GA)结合对培养基主要成分进行了优化。最终获得该菌株培养基的优化配方为:鱼蛋白胨29.89 g/L,胰蛋白胨23.33 g/L,柠檬酸三铵4.34 g/L,蔗糖15.00 g/L,低聚果糖15.00 g/L,乙酸钠5.00 g/L磷酸氢二钾0.40 g/L,七水硫酸镁0.58 g/L,一水硫酸锰0.29 g/L,吐温-801.00 g/L。在此培养基条件下,所得样品活菌数达到5.21×10^(9)CFU/mL,是未优化前的4.57倍。该研究对微生物高密度培养优化预测提供了新的方法。

健康婴儿粪便样本中加氏乳杆菌的分离鉴定及安全性评价

目的:本研究从125例健康婴儿粪便样本中分离鉴定出加氏乳杆菌(Lactobacillus gasseri)并对其安全性和抑菌性能进行评价。方法:本研究以1月龄健康婴儿粪便样本为对象,经过MRS培养基分离纯化、革兰氏染色、生化鉴定和16S rRNA测序技术进行菌种鉴定;随后,对分离得到的加氏乳杆菌利用血琼脂平板进行溶血性评价;利用微量肉汤稀释法对常见抗生素的药物敏性进行测定,并对加氏乳杆菌的安全性进行评价;最后,采用牛津杯法检测对大肠杆菌ATCC 25922和金黄色葡萄球菌ATCC 25923的抑制作用。结果:从125例健康婴儿粪便样本中成功分离并鉴定出15株加氏乳杆菌。溶血性检测结果显示,14株均无溶血性;待测菌株对四环素、万古霉素、利奈唑胺、利福平敏感性较高,对亚胺培南完全敏感,对甲氧苄啶完全耐药;抑菌实验结果显示,有6株菌同时对大肠杆菌和金黄色葡萄球菌具有抑菌效果。结论:本研究从健康婴儿粪便样本中成功分离筛选出3株安全性较高且对大肠杆菌和金黄色葡萄球菌同时具有一定抑制作用的加氏乳杆菌,编号分别为:LGI 6-1、LGI 6-2、LGI 6-3,作为潜在的益生菌资源,为后续深入探究加氏乳杆菌功能提供研究对象。

一株具有拮抗幽门螺杆菌作用的格氏乳杆菌生物学性质及其在发酵乳中应用

本研究探讨具有抗幽门螺杆菌作用的格氏乳杆菌的生物特性,结果表明L.gasseri Chen在MRS培养基生长比较慢,8 h进入生长对数期,26 h后进入稳定期;最适生长p H为5~7,最适生长温度为30~37℃,最适接种量为0.5%~2%（v/v）,可在0.1%的胆盐中生长,并能在5%的Na Cl中生长。在添加葡萄糖的复原乳中,L.gasseri Chen能进行单菌株发酵乳,且在4℃条件下可稳定保存21 d;L.gasseri Chen与普通酸奶发酵剂复合发酵制作的酸奶无不良风味,表明L.gasseri Chen可应用于商业上生产功能性酸奶。

婴儿肠道源格氏乳杆菌的安全性评价及益生特性

以广州1月龄婴儿肠道中分离出的乳酸杆菌为实验菌株,经分子生物学鉴定,确认为格氏乳杆菌(Lactobacillus gasseri)LGZ 1029。对格氏乳杆菌LGZ 1029进行体内外安全性评价和益生特性研究,结果表明:格氏乳杆菌LGZ 1029不产溶血毒素,对多类抗生素表现出敏感性,小鼠经口急性无毒;该菌具有较好的胃肠液耐受力及自凝聚能力,疏水性(79.75%)强于商业标准菌株鼠李糖乳杆菌ATCC 7469(43.01%);菌株对大肠杆菌ATCC 25922抑菌圈直径为17.31~20.70 mm,对金黄色葡萄球菌ATCC 12598的抑菌圈直径为21.71~31.08 mm,抑菌效果强于鼠李糖乳杆菌ATCC 7469;活菌数为1×10^(7)CFU/mL发酵液的1,1-苯基-2-三硝基苯肼自由基清除率可达87.07%。本实验为格氏乳杆菌LGZ 1029在膳食补充剂、乳品制造和防腐剂替代品领域的应用提供理论依据。

加氏乳杆菌的降脂活性研究

目的:探究加氏乳杆菌是否具有降脂活性,并验证其对HepG2细胞脂质堆积和高脂血症小鼠脂质代谢活性的影响。方法:利用油酸诱导建立HepG2细胞脂质堆积模型,通过多次油红O染色定量对166株加氏乳杆菌进行降脂活性筛选,选择活性最强的一株菌通过Bodipy染色、甘油三酯含量测定进行验证。利用C57BL/6J小鼠喂食高脂饲料建立高脂血症小鼠模型,灌胃加氏乳杆菌,每周测定小鼠的体质量,4周后测定其脂肪组织质量,并检测血清和肝脏组织中脂质水平。结果:61株加氏乳杆菌能够使脂质积累降低10%以上,占比36.75%,其中加氏乳杆菌BDUP活性最强。体外结果显示,与模型组NC相比,BDUP能够显著抑制HepG2细胞脂质堆积,降低TG含量。在体内实验中,与模型组相比,BDUP可以降低高脂血症小鼠体质量、脂肪质量及血脂、肝脂水平,其降脂功效优于标准菌株ATCC 33323。结论:36.75%的加氏乳杆菌具有稳定的调节脂代谢作用,其中菌株BDUP降脂活性最强,能够降低HepG2细胞脂质堆积,改善高脂血症小鼠脂质异常,表现出良好的体外和体内的降脂功效。

响应面法优化双层包埋格氏乳杆菌微胶囊制备工艺

为提高格氏乳杆菌的包埋率,增强菌体在人体内的定殖能力。该文利用响应面试验对双层包埋格氏乳杆菌微胶囊的制备工艺进行优化。确定最佳工艺条件为成膜时间15 min、壳聚糖浓度0.6%、pH5.2。制得双层包埋格氏乳杆菌微胶囊包埋率76.52%。经工艺优化后制得的微胶囊对人体酸环境耐受性明显增大,在人工肠液中1.0 h~1.5 h内释放完毕,贮藏稳定性显著提高。

马阴道微生态制剂的制备工艺研究

[目的]确定利用马源乳酸菌制备阴道微生态制剂的制备工艺参数。[方法]以分离自蒙古马阴道的格氏乳杆菌作为制备微生态制剂的菌株,利用发酵学技术及响应面法,对菌株的发酵培养基、工艺参数及制剂的配方和工艺参数进行优化。[结果]乳糖和大豆胨对菌粉的生长性能影响较大,工艺参数中发酵液初始pH值为6.6,温度为40℃,菌种接种量为6%时,对菌粉的发酵性能影响较大。而后利用药物制备学技术及响应面法,对制剂的配方及工艺参数进行了优化,结果显示,菌粉与淀粉、微粉硅胶、微晶纤维素混合比例167.05∶1.61∶1,多功能药用机转速为20 r/min,角度为60°时所制备制剂的活菌数较其他工艺条件下高。[结论]确定了利用马源格氏乳杆菌制备阴道微生态制剂的关键工艺参数,为进一步探索应用活菌制备的微生态制剂预防和治疗马阴道感染提供参考。

Lactobacillus gasseri LA39 promotes hepatic primary bile acid biosynthesis and intestinal secondary bile acid biotransformation

A growing body of evidence has linked the gut microbiota to liver metabolism.The manipulation of intestinal microflora has been considered as a promising avenue to promote liver health.However,the effects of Lactobacillus gasseri LA39,a potential probiotic,on liver metabolism remain unclear.Accumulating studies have investigated the proteomic profile for mining the host biological events affected by microbes,and used the germ-free(GF)mouse model to evaluate host-microbe interaction.Here,we explored the effects of L.gasseri LA39 gavage on the protein expression profiles of the liver of GF mice.Our results showed that a total of 128 proteins were upregulated,whereas a total of 123 proteins were downregulated by treatment with L.gasseri LA39.Further bioinformatics analyses suggested that the primary bile acid(BA)biosynthesis pathway in the liver was activated by L.gasseri LA39.Three differentially expressed proteins(cytochrome P450 family 27 subfamily A member 1(CYP27A1),cytochrome P450 family 7 subfamily B member 1(CYP7B1),and cytochrome P450 family 8 subfamily B member 1(CYP8B1))involved in the primary BA biosynthesis pathway were further validated by western blot assay.In addition,targeted metabolomic analyses demonstrated that serum and fecalβ-muricholic acid(a primary BA),dehydrolithocholic acid(a secondary BA),and glycolithocholic acid-3-sulfate(a secondary BA)were significantly increased by L.gasseri LA39.Thus,our data revealed that L.gasseri LA39 activates the hepatic primary BA biosynthesis and promotes the intestinal secondary BA biotransformation.Based on these findings,we suggest that L.gasseri LA39 confers an important function in the gut‒liver axis through regulating BA metabolism.

鼠李糖乳杆菌-格氏乳杆菌联用对阴道致病菌的抑制作用

目的本文通过提取细菌基因组进行16SrDNA PCR扩增和测序,分析菌株的进化树分支,鉴定一株乳酸菌菌株RD-0060并检测RD-0060与已有菌株RD-0046联用的抑菌能力和细胞粘附能力。方法结合现有菌株RD-0046(格氏乳杆菌,Lactobacillus gasseri),采用牛津杯法研究RD-0060单菌、RD-0060和RD-0046联用抑制致病菌的能力。通过共培养细菌和阴道上皮细胞VK2/E6E7,研究RD-0060单菌和RD-0060/RD-0046二联菌粘附能力。结果RD-0060为鼠李糖乳杆菌(Lactobacillus rhamnosus),具有抑制阿托波菌、阴道加德纳菌和常见好氧型病菌的功能,对阴道上皮细胞也有较强的粘附能力;RD-0060和RD-0046二联菌的抑菌效果和细胞粘附能力比单菌株更强。结论鼠李糖乳杆菌和格氏乳杆菌联用能显著抑制阴道致病菌生长,并且能够大量粘附阴道细胞,而且两菌株联用有协同效果,具有良好的临床应用和开发前景。

AJCN:过敏症来袭怎么办?新型益生菌组合疗法显神效

当进入过敏季节我们可能并不太会拿出手帕或者打喷嚏来预防过敏。日前，一项刊登在国际杂志The American Journal of Clinical Nutrition上的研究报告中。来自佛罗里达大学的研究人员通过研究发现。一种益生菌组合或许能够帮助减轻花粉症的症状。

热灭活乳酸菌TMC0356对代谢综合征大鼠肝脏脂代谢的影响及可能机制

目的探讨热灭活乳酸菌TMC0356对代谢综合征(metabolic syndrome,MS)大鼠肝脏脂代谢的影响及其可能的作用机制。方法选择雄性Sprague-Dawley大鼠60只,随机分为基础组、MS模型组和高、中、低剂量热灭活乳酸菌TMC0356实验组。各组以不同的饮食连续喂养7 d,饲养15周后解剖取出肝脏,检测肝脏中过氧化物酶体增生物激活受体-α(peroxisome proliferator activated receptor-α,PPAR-α)、固醇调节元件结合蛋白-1c(sterol regulatory element binding protein-1c,SREBP-1c)、脂肪酸合成酶(fatty acid synthase,FAS)、肉碱脂酰转移酶-1(carnitine palmitoyltransferase-1,CPT-1)等基因的mRNA及蛋白表达量。结果5组间的PPAR-α、SREBP-1c、CPT-1的mRNA表达量比较,差异均无统计学意义(P>0.05)。低剂量TMC0356实验组FAS的mRNA表达量低于MS模型组(P=0.011)、中剂量TMC0356实验组(P=0.042)、高剂量TMC0356实验组(P=0.009);其余组间两两比较,差异均无统计学意义(P>0.05)。PPAR-α、SREBP-1c、FAS的蛋白表达量在5组间比较,差异均无统计学意义(P>0.05)。低剂量TMC0356实验组CPT-1的蛋白表达量高于基础组(P=0.033)、高剂量TMC0356实验组(P=0.043);其余组间两两比较差异均无统计学意义(P>0.05)。结论热灭活乳酸菌TMC0356可以改善MS大鼠代谢紊乱的症状,这可以通过多种方式发生,如抑制MS大鼠的食欲,增加胰岛素抵抗,下调FAS、SREBP-1c等。