哺乳期需氧菌性阴道炎患者定期补充乳杆菌的疗效

目的分析在有效抗炎基础上定期补充乳杆菌活菌胶囊对哺乳期需氧菌性阴道炎患者的疗效及对远期复发率的影响。方法选择2019年4月至2020年3月于大连市妇女儿童医疗中心(集团)行产后42 d检查时发现的需氧菌性阴道炎患者共120例,按照随机自愿原则将所选患者分为观察组及对照组,各60例。全部患者均使用红核妇洁洗液及克林霉素磷酸酯阴道凝胶抗炎治疗7 d,观察组患者于第8天开始给予阴道用乳杆菌活菌胶囊每日睡前上药1粒,治疗10 d,停药后1周对两组患者进行临床疗效评估并了解不良反应发生情况。于首次治疗结束后第3个月及第6个月进行定期随诊,了解两组患者阴道炎的复发情况。且观察组患者于治疗后第3个月随诊结束后再次给予阴道用乳杆菌活菌胶囊补充上药1疗程。记录并比较两组患者治疗前、治疗后1周、治疗后第3个月及第6个月阴道pH值及H₂O₂情况。结果两组患者治疗期间均未发生明显不良反应。治疗后1周观察组患者治愈率(66.7%)显著高于对照组(36.7%),差异有统计学意义(P<0.05);观察组总有效率(95.0%)与对照组(86.7%)比较差异无统计学意义(P>0.05)。观察组治疗后第3个月复发率(5.0%)及第6个月复发率(11.7%)均明显低于同时段对照组(30.0%,56.7%),差异均有统计学意义(均P<0.05)。治疗后1周观察组患者阴道pH值正常率(95.0%)与对照组(86.7%)比较,差异无统计学意义(P>0.05),但观察组H₂O₂正常率(91.7%)明显高于对照组(63.3%),差异有统计学意义(P<0.05)。治疗后第3个月及第6个月观察组患者阴道pH值正常率(90.0%,85.0%)及H₂O₂正常率(86.7%,81.7%)均明显高于同时段对照组(53.3%、28.3%;45.0%、21.7%),差异均有统计学意义(均P<0.05)。结论在有效抗炎治疗基础上定期给予阴道用乳杆菌活菌胶囊补充治疗,能明显提高哺乳期需氧菌性阴道炎患者的治愈率,改善阴道pH值及H₂O₂情况,从而促进阴道微生态平衡,降低其复发率,值得临床应用。     

干酪乳杆菌arat基因的敲除及其对苯乳酸合成代谢的影响

苯乳酸（PLA）作为一种新型的广谱抑菌物质,在食品行业具有巨大的发展潜力,作为乳酸菌的天然代谢产物之一,对其代谢机理的研究具有非常重要的意义。通过CRISPR/Cas9基因编辑系统对一株干酪乳杆菌（Lactobacillus casei）1.8727的芳香族氨基转移酶基因arat进行敲除,得到一株arat缺失菌株（L. casei）1.8727Δarat。通过HPLC方法分析其代谢产物,发现发酵72 h时,PLA产量比出发菌株提高约66.7%,而苯丙氨酸（Phe）比出发菌株提高约57.8%。首次在L. casei 1.8727中成功应用基因编辑手段敲除了arat基因,研究表明该菌株具有自身合成代谢Phe的能力,arat作为PLA代谢途径的关键酶基因,其缺失并未使PLA产量下调,而是促进了PLA与Phe的合成代谢,证明干酪乳杆菌中可能存在其他的代偿途径,arat基因缺失所造成的代谢流的改变最终造成PLA与Phe产量的提高,同时PLA的合成代谢可能涉及多个基因的参与,是一个复杂的代谢网络。研究结果对于深入研究PLA的合成代谢机制具有重要意义,为后续PLA合成代谢途径提供了新的思路及方法。     

棒状乳杆菌FZU63发酵对红茶汤风味品质改善的作用

乳酸菌发酵可赋予茶饮料独特的香气与滋味,且可改变其物质组成,产生益生因子等。目前,针对乳酸菌在不同发酵阶段对茶汤中风味物质形成影响的研究较少。本研究以从中国传统泡菜中筛选获得的棒状乳杆菌FZU63为发酵菌株,对不同发酵阶段红茶汤中的挥发性香气成分、还原糖、游离氨基酸、有机酸等含量的变化过程进行分析,并对发酵红茶汤的感官品质进行评价。结果表明,棒状乳杆菌FZU63以红茶汤中的葡萄糖、果糖、甘露糖和木糖作为发酵过程中的主要碳源物质。红茶汤经棒状乳杆菌FZU63发酵作用后,香气成分丰度显著增加,且主要香气组分结构发生改变,发酵红茶汤在花香、坚果香的基础上增添了水果香;此外,部分苦味氨基酸含量下降,甜味和鲜味氨基酸含量增加;并且,乳酸、苹果酸、柠檬酸等有机酸含量在发酵过程中呈现积累。同时,感官评定结果表明棒状乳杆菌FZU63发酵可改善红茶汤的感官品质,且在发酵48h后达到较优。本文系统分析了经棒状乳杆菌发酵不同阶段对红茶汤风味的影响,可为乳酸菌发酵茶饮料的品质控制与产业化应用提供理论参考。     

Amelioration of regulatory T cells by Lactobacillus delbrueckii and Lactobacillus rhamnosus in pristane-induced lupus mice model

Regulatory T cells (Tregs) play an indispensable role in the control of immune responses and induction of peripheral tolerance. Dysregulation of Tregs is involved in the pathogenesis of systemic lupus erythematosus (SLE). Tolerogenic probiotics have shown beneficial effects in the control of autoimmune diseases. We evaluated the prophylactic and therapeutic effects of Lactobacillus delbrueckii and Lactobacillus rhamnosus on Tregs and their related molecules in pristane-induced lupus mice model. Fifty-four female BALB/c mice (3–5 weeks) were randomly divided into nine groups. Lupus was induced in all groups using pristane. Prophylactic groups were treated from Day 0 (at the time of pristane injection) and treatment groups were treated 2 months later with L. rhamnosus, L. delbrueckii, mix of both probiotics, and prednisolone. One group was considered as SLE-induced control group without any treatment. Presence of antinuclear antibodies (ANA), antidouble-stranded DNA (anti-dsDNA), antiribonucleoprotein (anti-RNP), proteinuria, and serum level of creatinine, urea, the expression of forkhead box P3 (Foxp3), interleukin 6 (IL-6), IL-10, transforming growth factor β, and the number of Tregs were determined. SLE induction by pristane led to the formation of lipogranuloma, presence of ANA, anti-dsDNA, and anti-RNP. Probiotics consumption decreased the level of lipogranuloma, ANA, and anti-dsDNA. In addition, in probiotics receiving groups, Tregs and the expression level of Foxp3 increased, while IL-6 decreased. The effect of probiotics in the prophylactic group was more prominent. The results may indicate the effectiveness of L. delbrueckii and L. rhamnosus in the enhancement of Tregs and the decrease of inflammatory cytokines and disease severity in SLE-induced mice.     

乳杆菌在模拟肉制品条件下结合苯并芘的效果

【背景】乳杆菌对众多致癌物具有吸附作用,但关于乳杆菌结合吸附苯并芘特性的研究并不多。【目的】探讨戊糖乳杆菌(Lactobacillus pentosus) ML32和植物乳杆菌(Lactobacillus plantarum)121对加工肉制品中苯并芘的吸附能力与吸附机制。【方法】基于HPLC检测菌体对不同模拟加工处理方式肉品中的苯并芘的吸附率。【结果】植物乳杆菌121和戊糖乳杆菌ML32对模拟油炸、烟熏或烧烤方式处理肉中苯并芘的吸附率均在30%以上。菌株121对直接烟熏肉中的苯并芘吸附率为41.21%,直接油炸肉中吸附率为38.71%,直接烧烤肉中吸附率为37.51%;菌株ML32对间接烟熏肉中的苯并芘吸附率为40.02%,间接烧烤肉中吸附率为38.01%。植物乳杆菌121适合于去除高温长时间加工肉中的苯并芘,戊糖乳杆菌ML32则相反。另外,乳杆菌细胞壁中的肽聚糖或许在吸附过程中发挥了主要作用。【结论】两株乳杆菌121和ML32具有吸附某些加工肉制品中苯并芘的效果,或许可以作为一种方法用于消除某些肉制品中因苯并芘过量带来的风险。     

Green synthesis of enantiopure (S)‐1‐(benzofuran‐2‐yl)ethanol by whole‐cell biocatalyst

Optically active aromatic alcohols are valuable chiral building blocks of many natural products and chiral drugs. Lactobacillus paracasei BD87E6, which was isolated from a cereal‐based fermented beverage, was shown as a biocatalyst for the bioreduction of 1‐(benzofuran‐2‐yl) ethanone to (S)‐1‐(benzofuran‐2‐yl) ethanol with highly stereoselectivity. The bioreduction conditions were optimized using L. paracasei BD87E6 to obtain high enantiomeric excess (ee) and conversion. After optimization of the bioreduction conditions, it was shown that the bioreduction of 1‐(benzofuran‐2‐yl)ethanone was performed in mild reaction conditions. The asymmetric bioreduction of the 1‐(benzofuran‐2‐yl)ethanone had reached 92% yield with ee of higher than 99.9% at 6.73 g of substrate. Our study gave the first example for enantiopure production of (S)‐1‐(benzofuran‐2‐yl)ethanol by a biological green method. This process is also scalable and has potential in application. In this study, a basic and novel whole‐cell mediated biocatalytic method was performed for the enantiopure production of (S)‐1‐(benzofuran‐2‐yl)ethanol in the aqueous medium, which empowered the synthesis of a precious chiral intermediary process to be converted into a sophisticated molecule for drug production.     

Intranasal administration of Lactobacillus rhamnosus GG protects mice from H1N1 influenza virus infection by regulating respiratory immune responses

Aims: To investigate whether intranasal Lactobacillus administration protects host animals from influenza virus (IFV) infection by enhancing respiratory immune responses in a mouse model. Methods and Results: After 3 days of intranasal exposure to Lactobacillus rhamnosus GG (LGG), BALB/c mice were infected with IFV A/PR/8/34 (H1N1). Mice treated with LGG showed a lower frequency of accumulated symptoms and a higher survival rate than control mice (P < 0·05). The YAC‐1 cell‐killing activity of lung cells isolated from mice treated with LGG was significantly greater than those isolated from control mice (P < 0·01). Intranasal administration of LGG significantly increased mRNA expression of interleukin (IL)‐1β, tumour necrosis factor (TNF) and monocyte chemotactic protein (MCP)‐1 (P < 0·01). Conclusions: These results suggest that intranasal administration of LGG protects the host animal from IFV infection by enhancing respiratory cell‐mediated immune responses following up‐regulation of lung natural killer (NK) cell activation. Significance and Impact of Study: We have demonstrated that probiotics might protect host animals from viral infection by stimulating immune responses in the respiratory tract.     

Expanded bed adsorption as a unique unit operation for the isolation of bacteriocins from fermentation media

Expanded bed adsorption using a strong cation exchanger allowed the direct isolation of amylovorin L471, a bacteriocin from Lactobacillus amylovorusDCE 471, from the fermentation medium. The pH of the loading and elution buffer were optimised in a packed bed with cell-free culture supernatant. Bound bacteriocin was eluted with 1.0 M NaCl. The highest recovery (30%) was obtained at the lowest pH (3.6). At higher pH values the recovery was lower, namely 12%, 15% and 7% at pH 4.5, 6.5 and 8.0, respectively. In expanded bed mode, direct isolation of the bacteriocin from the fermentation medium at pH 3.6 (loading and elution) initially resulted in a recovery of 12%. After optimisation of the pH (loading and elution at pH 3.6 and 6.5, respectively), the recovery for amylovorin L471 increased up to 30% and higher. Recovery of enterocin A from Enterococcus faeciumCTC 492 fermentation medium averaged 15% (loading and elution at pH 3.6 and 6.0, respectively). With pediocin, produced by Pediococcus acidilactici ATCC 8042, 26% recovery was obtained at a pH of 6.5 during loading and elution. Low recoveries can be ascribed to non-optimal operation conditions (pH of loading and elution buffer), inactivation of the bacteriocin on a cationic resin, and the formation of more insoluble and less active, strongly hydrophobic bacteriocin aggregates upon further purification.