Lactobacillus plantarum 299v Inhibits Escherichia coli-Induced Intestinal Permeability

The purpose of this work was to investigate whether a probiotic bacterium, Lactobacillus plantarum 299v, could affect Escherichia coli-induced passage of mannitol across the intestinal wall. Sprague-Dawley rats were pretreated for one week by either tube feeding with L. plantarum 299v twice daily, free access to L. plantarum 299v by adding the bacterium in the drinking water, or negative control receiving regular feeding. Intestinal segments were mounted in Ussing chambers and the mucosa was exposed to control medium, E. coli, and L. plantarum 299v (alone or together). [¹⁴C]Mannitol was added as a marker of intestinal permeability and samples were taken from the serosal side. E. coli exposure induced a 53% increase in mannitol passage across the intestinal wall (P < 0.05). One week of pretreatment with L. plantarum 299v in the drinking water abolished the E. coli-induced increase in permeability. Tube feeding for one week or short-term addition of L. plantarum 299v in the Ussing chambers had no effect on the permeability provoked by E. coli challenge. Notably, L. plantarum 299v itself did not change the intestinal passage of mannitol. These data demonstrate that pretreatment with L. plantarum 299v, which is a probiotic bacterium, protects against E. coli-induced increase in intestinal permeability, and that L. plantarum 299v alone has no influence on the intestinal permeability. Thus, this study supports the concept that probiotics may exert beneficial effects in the gastrointestinal tract.     

Isolation and characterization of two exopolysaccharides produced by Lactobacillus plantarum EP56

A Lactobacillus plantarum strain producing exopolysaccharides (EPSs) was isolated from corn silage. When this strain, named L. plantarum EP56, was grown on a chemically defined medium, two EPS fractions were isolated. The cell-bound EPS fraction (EPS-b) was composed of a single high-molecular-mass polymer of 8.5x10(5) Da containing glucose, galactose and N-acetylgalactosamine in a molar ratio of approximately 3:1:1 and traces of glycerol and phosphoglycerol. The released EPS fraction (EPS-r) was composed of the high-molecular-mass bound polysaccharide and a second polymer of 4x10(4) Da containing glucose, galactose and rhamnose in a molar ratio of 3:1:1 and traces of glycerol and phosphoglycerol. EPS-b and EPS-r contained phosphate which contributes to their negative net charge. Studies on polysaccharide production and location showed that both polymers were synthesized during the exponential growth phase and that the EPS-b polymer was progressively released into the culture medium during the stationary growth phase. Carbon source and temperature influenced EPS synthesis when L. plantarum EP56 was grown in a chemically defined medium. Lactose was the most efficient carbon source among the five tested (glucose, galactose, fructose, lactose and sucrose). EPS production was also increased when the incubation temperature is lowered.     

乳酸菌Z222产胞外多糖(EPSⅠ)对免疫细胞功能的影响

目的　检测乳酸菌Z2 2 2 产胞外多糖EPSⅠ对体外免疫细胞功能的调节作用。方法　不同浓度的EPSⅠ作用于小鼠的腹腔巨噬细胞和脾细胞 ,分别用中性红染色法检测巨噬细胞的吞噬能力 ,用MTT法检测淋巴细胞在体外的转化能力、NK细胞杀伤肿瘤细胞Yac 1的能力和产细胞因子IL 2的活性。结果　 (1)EPSⅠ单独作用小鼠脾细胞就能促进体外淋巴细胞增殖 ,且表现出剂量依赖关系。EPSⅠ亦可促进ConA诱导的体外小鼠淋巴细胞转化。 (2 )EPSⅠ体外作用于小鼠腹腔巨噬细胞均可提高MΦ的吞噬能力 ,与对照组比较差异都有显著性。 (3)与对照组相比EPSⅠ能增加体外NK细胞的活性 ,杀伤率最大值达 6 2 .4 1%± 2 .5 4 %。 (4 )EPSⅠ使小鼠脾细胞产IL 2的能力与对照组比较 ,差异有显著性。结论　乳酸菌多糖EPSⅠ对小鼠的免疫功能有一定的调节作用。     

The Effects of Lactobacillus rhamnosus on the Prevention of Asthma in a Murine Model

Purpose

Lactobacilli are probiotic bacteria that are effective in the management of allergic diseases or gastroenteritis. It is hypothesized that such probiotics have immunoregulatory properties and promote mucosal tolerance. Our goal was to investigate whether Lactobacillus casei rhamnosus Lcr35 could inhibit airway inflammation in an ovalbumin (OVA)-induced murine model of asthma.

Methods

BALB/c mice aged 6 weeks were used in the present study. Lactobacillus casei rhamnosus Lcr35 was administered daily, starting 1 week prior to the first OVA sensitization (group 1) and 2 days before the first 1% OVA airway challenge (group 2). Mice that received only saline at both sensitization and airway challenge time points were used as negative controls (group 3), and those that had OVA-induced asthma were used as positive controls (group 4). Airway responsiveness to methacholine was assessed, and bronchoalveolar lavage (BAL) was performed. At the endpoint of the study, total IgE as well as OVA-specific IgE, IgG₁ and IgG_2a in serum was measured by enzyme-linked immunosorbent assay. Lung pathology was also evaluated.

Results

Airway hyperresponsiveness, total cell counts and the proportion of eosinophils in BAL fluid were significantly decreased in group 1 compared with group 4 (P<0.05). Total serum IgE levels were also significantly decreased in group 1 compared with group 4. Serum levels of OVA-specific IgE, IgG₁ and IgG_2a were not significantly influenced by treatment with Lcr35. There was significantly less peribronchial and perivascular infiltration of inflammatory cells in group 1 compared with group 4; however, there were no significant differences in methacholine challenge, BAL, serology or histology between groups 2 and 4.

Conclusions

Oral treatment with Lcr35 prior to sensitization can attenuate airway inflammation and hyperreactivity in a mouse model of allergic airway inflammation. These results suggest that Lcr35 may have potential for preventing asthma.     

Interleukin-12 is involved in the enhancement of human natural killer cell activity by Lactobacillus casei Shirota

We conducted a placebo-controlled, cross-over trial to examine the effect of Lactobacillus casei Shirota (LcS) on natural killer (NK) cell activity in humans. NK cell activity exhibited a declining trend during the period of placebo ingestion, but NK cell activity increased after intake for 3 weeks of fermented milk containing 4 x 10(10) live LcS. When human peripheral blood mononuclear cells were cultured in the presence of heat-killed LcS, NK cell activity was enhanced. The ability of LcS to enhance NK cell activity and induce interleukin (IL)-12 production was correlated, and the addition of anti-IL-12 monoclonal antibody reduced the enhancement of NK cell activity triggered by LcS. In addition, separation of NK cells from LcS-stimulated monocytes with membrane filter reduced NK cell activity to the intermediate level and almost deprived monocytes of the ability to produce IL-12. These results demonstrate that LcS can enhance NK cell activity in vivo and in vitro in humans, and IL-12 may be responsible for enhancement of NK cell activity triggered by LcS.     

阴道乳杆菌对常见阴道假丝酵母菌抑制作用的体外试验研究

目的:观察阴道乳杆菌菌株在体外实验中对假丝酵母菌生长的抑制作用。方法:分离健康妇女阴道中常见的乳杆菌和外阴、阴道假丝酵母菌病(vulvovaginal candidiasis,VVC)患者阴道中的常见假丝酵母菌,采用96孔板混合生长抑制法观察处于生长对数期的乳杆菌对假丝酵母菌生长的抑制作用。结果:23例健康妇女阴道分泌物中分离出3种乳杆菌:嗜酸乳杆菌(La)、干酪乳杆菌(Lca)和卷曲乳杆菌(Lcr),15例VVC初发患者阴道分泌物中分离出3种假丝酵母菌:白色假丝酵母菌(Ca)、热带假丝酵母菌(Ct)和克柔假丝酵母菌(Ck)。各种乳杆菌均表现出对假丝酵母菌生长的抑制能力,La对各种假丝酵母菌的抑制能力均优于Lcr;与Lca相比,La对Ct的抑制更为明显;产H2O2的Lcr与不产H2O2的Lca对假丝酵母菌的抑制能力无显著差异。结论:各种乳杆菌表现出对假丝酵母菌生长的不同抑制能力,La对研究的3种假丝酵母菌的抑制能力均优于Lcr;与Lca相比,La的唯一优势体现在对Ct的抑制上;乳杆菌对假丝酵母菌的抑制可能不仅仅与产生H2O2能力有关。     

阴道微生态菌群与宫颈疾病相关性的研究进展

宫颈疾病包括宫颈炎症、宫颈鳞状上皮内病变及宫颈癌,近年研究发现阴道微生物菌群产生的细胞因子及局部免疫系统与宫颈疾病的发生、发展有关。正常女性的阴道微生态环境由多种微生物构成,其中乳杆菌对维持阴道微生态平衡发挥着重要作用。宫颈癌在女性恶性肿瘤中发生率位居第一,其发生与人乳头瘤病毒(HPV)持续感染密切相关,但并非所有感染HPV者均患宫颈癌,其病因为多因素综合作用。因乳杆菌变化导致的阴道疾病与HPV感染相互作用,共同参与宫颈疾病的发生、进展,系统有效的阴道微生态环境检测对及时调节阴道微生态平衡非常重要。阴道微生物菌群与宫颈疾病之间的关系成为许多学者的研究热点,综述阴道微生态与宫颈疾病发生、发展的相关性,为宫颈疾病尤其是宫颈癌的预防、治疗及预后提供理论依据。     

Prenatal administration of Lactobacillus rhamnosus has no effect on the diversity of the early infant gut microbiota

We have recently shown that maternal administration of Lactobacillus rhamnosus GG (LGG) during late pregnancy can have beneficial effects on the early development of infant gut microbiota, promoting a bifidobacteria profile similar to that of a healthy breastfed infant. It is uncertain, however, whether such probiotic supplementation could influence the diversity of infant gut microbiota. We investigated the effect of pre-natal LGG on gut microbial diversity in the early post-natal period. Day-7 faecal samples were collected from 98 infants at high risk of allergic disease, whose mothers participated in a pre-natal probiotic eczema prevention study. Faecal microbial diversity was assessed by terminal restriction fragment length polymorphism using restriction enzymes Sau96I and AluI. A greater number of peaks represent greater diversity of bacterial communities. Administration of LGG to mothers during late pregnancy had no effects on the mean number of peaks in faecal samples from 1-wk-old infants as compared to placebo (AluI 14.4 vs. 15.5, p?=?0.17, 95% CI -0.4, 2.5; Sau96I 17.3 vs. 15.8, p?=?0.15, 95% CI -3.5, 0.5). Prenatal LGG failed to modulate diversity of early infant gut microbiota despite promoting a beneficial bifidobacteria profile.     

Lactobacillus crispatus strain SJ‐3C‐US induces human dendritic cells (DCs) maturation and confers an anti‐inflammatory phenotype to DCs

Lactobacillus crispatus is one of the most predominant species in the healthy vagina microbiota. Nevertheless, the interactions between this commensal bacterium and the immune system are largely unknown. Given the importance of the dendritic cells (DCs) in the regulation of the immunity, this study was performed to elucidate the influence of vaginal isolated L. crispatus SJ‐3C‐US from healthy Iranian women on DCs, either directly by exposure of DCs to ultraviolet‐inactivated (UVI) and heat‐killed (HK) L. crispatus SJ‐3C‐US or indirectly to its cell‐free supernatant (CFS), and the outcomes of immune response. In this work we showed that L. crispatus SJ‐3C‐US induced strong dose‐dependent activation of dendritic cells and production of high levels of IL‐10, whereas IL‐12p70 production was induced at low level in an inverse dose‐dependent manner. This stimulation skewed T cells polarization toward CD4⁺ CD25⁺ FOXP3⁺ Treg cells and production of IL‐10 in a dose‐dependent manner in mixed leukocyte reaction (MLR) test. The mode of bacterial inactivation did not affect the DCs activation pattern, upon encounter with L. crispatus SJ‐3C‐US. Moreover, while DCs stimulated with CFS showed moderate phenotypic maturation and IL‐10 production, it failed to skew T cells polarization toward CD4⁺ CD25⁺ FOXP3⁺ regulatory T cells (Treg) and production of IL‐10. This study showed that L. crispatus SJ‐3C‐US confers an anti‐inflammatory phenotype to DCs through up‐regulation of anti‐inflammatory/regulatory IL‐10 cytokine production and induction of CD4⁺ CD25⁺ FOXP3⁺ T cells at optimal dosage. Our findings suggest that L. crispatus SJ‐3C‐US could be a potent candidate as protective probiotic against human immune‐mediated pathologies, such as chronic inflammation, vaginitis or pelvic inflammatory disease (PID).     

Assessment of immunization as a technique to extend the chilled storage life of vacuum‐packaged lamb

The growth at — 1.5°C of Lactobacillus delbrueckii, a meat spoilage organism, was evaluated on vacuum‐packaged lamb legs obtained from animals immunized against that organism. Growth was significantly lower than that on similarly treated legs obtained from non‐immunized lambs. These findings suggest that immunization against spoilage organisms may contribute toward increasing the chilled storage life of fresh meat.