红茶对新生幼鼠肠道菌群形成的影响

探讨红茶对新生幼鼠肠道菌群形成的影响,为从微生态角度研究红茶在人体肠道菌群形成过程中的作用机制奠定基础。

利用宏基因组测序技术检测4周龄新生幼鼠（4weeks组,n = 30）、12周龄正常对照组小鼠（control组,n = 15）和12周龄喂饲红茶水实验组小鼠（teadrink组,n = 15）的肠道菌群分布,分析3组样本的菌群差异情况,探求红茶对新生幼鼠肠道菌群形成的影响。

与control组相比,teadrink组小鼠肠道拟杆菌门（t = −7.711,P＜0.001）、拟杆菌科（t = −3.411,P = 0.009）、长尾嗤菌体科（t = −2.515,P = 0.036）、拟杆菌属（t = −2.693,P = 0.027）、邓肯菌属（t = −2.434,P = 0.041）、居海事城球杆菌属（t = −3.327,P = 0.029）、迪博邓肯菌（t = −2.679,P = 0.028）、普通居海事城球杆菌（t = −3.401,P = 0.027）和Duncaniella_sp._C9（t = −3.104,P = 0.035）相对丰度显著增加,厚壁菌门（t = 8.952,P＜0.001）、乳杆菌科（t = 13.102,P＜0.001）、消化链球菌科（t = 3.665,P = 0.021）、爱格菌科（t = 4.481,P = 0.002）、理研菌科（t = 3.626,P = 0.022）、乳杆菌属（t = 5.542,P = 0.004）、黏液乳杆菌属（t = 6.334,P = 0.002）、龙包茨菌属（t = 3.785,P = 0.005）、阿德勒菌属（t = 4.504,P = 0.002）、约氏乳杆菌（t = 4.282,P = 0.011）和罗伊氏粘液乳杆菌（t = 6.156,P = 0.003）相对丰度显著减少。与4weeks组相比,teadrink组小鼠肠道菌群分布差异大于control组。

红茶对新生幼鼠肠道菌群的形成能够产生影响,不同丰度的菌群可能通过调节碳水化合物代谢等途径来达到改善肠道菌群结构、增强肠道稳态的目的,具体代谢机制有待深入研究。

     

约氏乳杆菌GLJO02通过改善肠道通透性缓解DSS诱导的小鼠结肠炎

探究约氏乳杆菌GLJO02对DSS诱导的小鼠结肠炎的影响。

从灌胃普洱茶的小鼠粪便中筛选得到益生菌约氏乳杆菌GLJO02。将18只SPF级C57小鼠随机分成3组：Control+PBS组（6只）、DSS+PBS组（6只）及DSS+GLJO02组（6只）,均自由饮用含3% DSS水7 d以建立结肠炎模型,其中DSS+GLJO02组提前1周灌胃GLJO02菌液;造模期间观察小鼠体质量变化情况及粪便性状改变情况;于造模第8天处死小鼠并留取小鼠血清及肠道样品,检测小鼠血清中LPS水平以评估肠道通透性,通过H&E染色评估小鼠结肠病理情况,通过实时荧光定量技术检测小鼠结肠中炎症因子及紧密连接蛋白的表达情况,通过免疫荧光法检测紧密连接蛋白ZO-1及Occludin的表达情况,并通过高效液相色谱法检测小鼠盲肠内容物中短链脂肪酸的含量。

与Control+PBS组相比,DSS+PBS组小鼠体质量显著降低、DAI评分提高同时结肠长度缩短。与DSS+PBS组相比,DSS+GLJO02组小鼠症状缓解,体质量下降显著改善（t = 6.948,P＜0.000 1）,结肠长度提高（t = 3.790,P = 0.003 4）,DAI评分显著降低（t = 11.880,P＜0.000 1）;组织病理学评分显著下降（t = 10.410,P = 0.000 1）;促炎症因子表达水平降低;免疫荧光检测结果显示ZO-1、Occludin蛋白表达增多;应用高效液相色谱法发现GLJO02处理后能够显著提升盲肠中短链脂肪酸的含量（乙酸：t = 4.042,P = 0.005 4;丙酸：t = 12.380,P＜0.000 1;丁酸：t = 7.819,P＜0.000 1）。

约氏乳杆菌GLJO02能够通过改善肠道通透性,起到缓解DSS诱导的结肠炎的作用。

     

氨基酸型肠内营养制剂支持后克罗恩病患者肠道微生物和非靶向代谢组学指标的分析

探讨氨基酸型肠内营养制剂支持后克罗恩病患者的肠道微生物和非靶向代谢组学指标的变化,为该类患者的治疗提供参考。

选择我院收治的20例克罗恩病活动期患者作为研究对象,所有患者均采用氨基酸型肠内营养制剂进行支持治疗。比较患者治疗前后肠道菌群结构、菌群多样性以及非靶向代谢组学检测结果的差异。

治疗后,患者肠道乳杆菌属（t=5.200,P＜0.001）、大肠埃希菌（t=11.974,P＜0.001）、克雷伯菌属（t=15.033,P＜0.001）、糖单胞菌（t=12.166,P＜0.001）、恶臭假单胞菌（t=31.063,P＜0.001）、肠球菌属（t=28.867,P＜0.001）数量均显著升高;同时患者肠道菌群OUTs（t=40.435,P＜0.001）、Observed species（t=5.475,P＜0.001）、Chao1指数（t=12.348,P＜0.001）、Simpson指数（t=2.961,P=0.005）、Shannon指数（t=3.330,P=0.002）均显著升高。相比治疗前,治疗后患者血清以及粪便中的氨基酸、多肽、脂肪酸、胆固醇及碳水化合物水平均显著改善。

氨基酸型肠内营养制剂支持后,克罗恩病患者肠道菌群丰度提高,同时患者脂质代谢的改善可能与氧化应激反应通路相关联。

     

乳杆菌及双歧杆菌缓解便秘的机制

探讨可改善患者便秘症状的植物乳植杆菌LP45、嗜酸乳杆菌La28和动物双歧杆菌乳亚种BAL531的作用机制。

采用HT-29细胞与肠道菌群体外批量发酵系统结合的方法,检测益生菌增殖肠上皮细胞、提升肠道紧密连接性与黏膜屏障能力以及增强五羟色胺转运体（SERT）、水通道蛋白-3（AQP-3）表达的能力。

菌株LP45和BAL531均具有较好的黏附能力并能够增殖肠上皮细胞,菌株La28无增殖作用;菌株LP45、La28和BAL531能显著提升紧密连接蛋白ZO-1和Occludin的mRNA相对表达水平,最高达2.73倍（t = 13.099,P＜0.001）,从而增强肠道屏障。菌株LP45使黏蛋白（MUC2）mRNA相对表达量显著提升1.89倍（t = 10.285,P = 0.001）,菌株La28与BAL531无显著影响;菌株LP45、La28和BAL531使SERT mRNA相对表达量分别提升2.13倍、1.45倍和4.00倍,其中菌株BAL531效果最显著（t = 21.308,P＜0.001）;另外,菌株LP45可使AQP-3 mRNA相对表达量提升2.12倍（t = 10.625,P＜0.001）,菌株BAL531使AQP-3 mRNA相对表达量下调0.79倍（t = ‒2.611,P = 0.059）,菌株La28无显著影响（t = ‒0.951,P = 0.395）。

菌株LP45、La28和BAL531对便秘症状的缓解作用可能是通过特异性增加肠道润滑、促进肠道蠕动、减缓肠道水液吸收等不同机制实现的。

     

慢性肾衰竭患者肠道菌群改变与肾小球滤过率的关系

探究慢性肾衰竭患者肠道菌群结构改变与肾小球滤过率的关系。

选取2017年3月至2020年3月我院收治的202例慢性肾衰竭患者作为试验组, 并选取198例同期健康体检者作为对照组。收集两组入选者粪便标本并进行检测, 对比两组入选者肠道菌群数量; 同时对比两组入选者体质量、肾小球滤过率、血肌酐、血尿素氮、血胱抑素C水平, 采用Pearson相关性分析肠道菌群改变与肾小球滤过率的相关性。

相比于对照组, 试验组患者肠道双歧杆菌(t=21.915, P < 0.001)、大肠埃希菌数量显著降低(t=18.220, P < 0.001), 肠球菌数量显著增高(t=16.782, P < 0.001)。相比于对照组, 试验组患者肾小球滤过率(t=147.035, P < 0.001)显著降低, 血肌酐(t=43.129, P < 0.001)、血尿素氮(t=170.206, P < 0.001)、血胱抑素C(t=22.432, P < 0.001)水平显著增高。Spearman相关性分析显示, 慢性肾衰竭患者肠道双歧杆菌(r=-0.695, P < 0.001)和大肠埃希菌(r=-0.631, P < 0.001)与肾小球滤过率呈负相关。Logistic回归分析显示, 双歧杆菌、大肠埃希菌、肠球菌、血肌酐、血尿素氮和血胱氨酸均是慢性肾衰竭患者肾小球滤过率降低的独立危险因素。

慢性肾衰竭患者肠道双歧杆菌和大肠埃希菌数量降低、肠球菌数量升高, 且与肾小球滤过率呈显著负相关。

     

低聚果糖对AOM/DSS诱导的结肠炎相关结直肠癌小鼠辅助性T细胞的调控作用

探讨益生元低聚果糖（FOS）对结肠炎相关结直肠癌（CAC）小鼠肠道辅助性T细胞的调节作用。

将6周龄SPF级雄性C57BL6小鼠（体重18～20 g）随机分为对照组、模型组和干预组,每组10只。通过偶氮甲烷、葡聚糖硫酸钠构建CAC小鼠模型,干预组每日使用2 mg/kg b.w. FOS灌胃,持续10周。造模期间监测各组小鼠体重变化,造模结束后测量结肠长度和肿瘤数目。采用微球免疫分析法检测血清Th1/Th2/Th17相关细胞因子水平,流式细胞术分析肠系膜淋巴结内Th1、Th2、Th17细胞亚群比例。

与模型组相比,干预组小鼠结肠长度显著增加（t=3.106,P=0.006 4）,肿瘤数目显著减少（U=15.000,P=0.011 1）,血清中IL-17A（t=3.504,P=0.008 8）、TNF-α（t=2.381,P=0.030 0）等促炎细胞因子水平降低,肠系膜淋巴结Th17细胞比例显著降低（t=6.031,P=0.002 7）,Th1/Th2显著升高（t=2.419,P=0.038 7）。

FOS可调控CAC模型小鼠结肠内辅助性T细胞的分化,抑制肿瘤的发生。

     

鼠李糖乳酪杆菌RH0121冻干工艺优化及降血糖作用的研究

优化鼠李糖乳酪杆菌（Lacticaseibacillus rhamnosus）RH0121的冻干工艺,探究其辅助降血糖作用。

通过单因素试验和响应面试验,优化鼠李糖乳酪杆菌RH0121冻干粉的生产工艺;同时利用小鼠实验,探究服用冻干粉后小鼠的体质量、口服葡萄糖耐量和血清生化指标水平的变化。

优化后的工艺为发酵时间9 h,发酵温度37 ℃,接种量4%,冻干时间50 h。经验证,冻干粉活菌数为5.5×10¹¹ CFU/g。灌胃冻干粉样品后的小鼠体质量缓慢回升,小鼠灌胃后120 min血糖水平低于灌胃前（P＜0.05）。灌胃后,样品组小鼠血清TC、TG、LDL和TNF-α水平均低于模型组,INS水平高于模型组（均P＜0.05）。

鼠李糖乳酪杆菌RH0121具有辅助降血糖作用,可为开发其他降血糖产品提供原料。

     

一种复合益生菌粉增强免疫力功能的动物研究

通过细胞免疫、体液免疫、单核巨噬细胞吞噬功能、NK细胞活性测定试验检验由植物乳植杆菌HEAL9和副干酪乳酪杆菌8700:2配制而成的复合益生菌粉对小鼠免疫力功能的影响。

将50只雄性BALB/c小鼠按体质量随机分为阴性对照组、阳性对照组以及益生菌粉低、中和高剂量组,每组10只,分别使用去离子水、转移因子口服液和相应浓度的益生菌粉进行灌胃给药,1次/d,连续30 d。实验过程中分别对小鼠进行迟发型变态反应试验、抗体生成细胞检测及血清溶血素生成试验。末次给药次日,对小鼠进行淋巴细胞转化的影响试验、碳廓清试验和腹腔巨噬细胞吞噬鸡红细胞试验。并委托细胞室进行靶细胞（YAC-1）传代,进行NK细胞活性试验。

与阴性对照组相比,益生菌粉低、中、高剂量组小鼠脾淋巴细胞增殖能力、抗体积数及NK细胞活性均升高,益生菌粉高剂量组小鼠耳肿胀度、溶血空斑数、吞噬指数及吞噬百分率升高,差异均有统计学意义（P＜0.05或P＜0.01）。

依照《保健食品功能评价方法（2020年版）（征求意见稿）》有助于增强免疫力功能检验方法及结果判定,判定该复合益生菌粉具有增强免疫力功能作用。

     

具有分解嘌呤核苷能力的益生菌菌株筛选

在不同的肠道菌群及奶制品样品中筛选益生菌菌株,对其耐酸和耐胆盐能力、分解嘌呤核苷能力进行评价,为后续研发治疗高尿酸血症益生菌制剂提供依据。

采集内蒙古地区及巴马长寿村的健康婴儿肠道菌群或奶豆腐、奶疙瘩制品,通过选择性培养基划线培养、镜检及16S rDNA测序的方式筛选益生菌菌株。通过耐酸、耐胆盐试验,模拟胃液和模拟肠液筛选出对胃肠道环境耐受能力强的菌株并通过电镜观察其形态。再进一步通过分解嘌呤核苷能力检测确定分解能力最优的菌株。

在8个样本中筛选出23株益生菌,对其胃肠耐受能力进行检测后发现筛选出了8株耐受能力较强的益生菌菌株,分别为鼠李糖乳酪杆菌RH01103,罗伊氏粘液乳杆菌HCS02-001,植物乳植杆菌RH03010,动物双歧杆菌乳亚种RH04020,发酵粘液乳杆菌RH08050,副干酪乳酪杆菌HCS17-040,乳酸片球菌RH27102和戊糖片球菌RH34011。通过对分解嘌呤核苷能力检测,发现与未接种益生菌的空白对照组相比,罗伊氏粘液乳杆菌HCS02-001和副干酪乳酪杆菌HCS17-040对肌苷和鸟苷的分解能力最显著（P = 0.0002, P＜0.0001）。

8个样本筛选出的23株益生菌中罗伊氏乳杆菌HCS02-001和副干酪乳杆菌HCS17-040的胃肠耐受能力最强,分解嘌呤核苷效率最高。

     

高校女性日常能耗与肠道菌群的相关性研究

探讨高校女性日常能耗及肠道菌群结构特征,分析不同能耗指标与特征肠道菌群之间的相关性。

基于智能可穿戴设备人体运动能耗检测仪对广州两所大学的青年女性（Y组,n=30）、中年女性（M组,n=30）进行48 h能耗监测,统计分析日常能耗的组间差异。采集调查对象清晨粪便进行16S rRNA基因测序,运用多元统计学分析中青年女性肠道菌群结构特征。将目、属水平的特征菌群与能耗指标进行相关性检验及回归分析。

Y组人群的日均步数（t=4.250,P＜0.001）、每日能耗值（t=3.590,P＜0.001）、日均中高强度活动时长（t=4.357,P＜0.001）均显著高于M组;两组人群肠道菌群的目、属水平的丰度差异菌群主要为乳杆菌目（Lactobacillales）（t=2.537,P=0.014）、小杆菌属（Dialister）（t=2.904,P=0.005）、布劳特菌属（Blautia）（t=3.246,P=0.002）,其中Lactobacillales和Dialister与多项能耗指标呈正相关,Blautia与多项能耗指标呈负相关。

日均步数、每日能耗值、日均中高强度活动时长的能耗指标可用于预测更好的身体机能;一定条件下,增加低、中、高强度活动时长可能提高Lactobacillales和Dialister的丰度,进而延缓身体机能下降。

     

鼠李糖乳杆菌LV108及其发酵乳免疫调节作用的比较

目的 探讨鼠李糖乳杆菌LV108及其发酵乳对免疫抑制小鼠免疫功能的调节作用。 方法 将BALB/c小鼠随机分为5组,每组10只,即空白组(正常小鼠)、模型组(免疫抑制小鼠)、药物组(免疫抑制小鼠食物中添加左旋咪唑)、LV108菌悬液组(免疫抑制小鼠食物中添加LV108菌悬液)和LV108发酵乳组(免疫抑制小鼠食物中添加LV108发酵乳),除空白组外其余组构建免疫抑制小鼠模型。干预4周后,分别测定各组小鼠体质量和脏器指数,血清中白细胞介素2(IL2)、肿瘤坏死因子α(TNFα)和免疫球蛋白G(IgG)含量,血清溶血素含量、耳肿胀度和肝、脾巨噬细胞吞噬能力。 结果 相比模型组,LV108菌悬液组和LV108发酵乳组小鼠体质量增长速度、脏器指数、血清IL2与IgG水平、血清溶血值、耳肿胀度和巨噬细胞吞噬能力显著升高(均P结论 LV108菌体及发酵乳对免疫抑制小鼠具备较全面的免疫调节作用,均可提高小鼠的自身免疫力;LV108发酵乳对小鼠的免疫调节作用强于LV108菌体。     

植物乳杆菌P-8对小鼠免疫功能的调节作用研究

摘要 目的：不同类型的益生菌株免疫调节功能各异。本文旨在评价植物乳杆菌P-8（Lactobacillus plantarum P-8）对小鼠免疫功能的调控作用及机制。方法：C57BL/6J小鼠每日灌胃给予不同剂量的植物乳杆菌P-8（0. 25 mg/kg、0.5 mg/kg、1.5 mg/kg）,连续30天,记录小鼠一般情况。给药结束后处死动物,测定小鼠脏器/体重比;小鼠碳廓清实验、小鼠腹腔巨噬细胞吞噬鸡红细胞实验评价各组小鼠的单核-巨噬细胞功能;血清溶血素测定、抗体生成细胞实验评价各组小鼠的体液免疫功能;脾淋巴细胞转化实验、迟发型变态反应实验评价各组小鼠的细胞免疫功能;NK细胞的活性测定实验评价小鼠的NK细胞活性。结果：与对照组相比,低、中、高剂量组植物乳杆菌P-8对小鼠脏器/体重比值差异无统计学意义（P>0.05）;且植物乳杆菌P-8可显著提高小鼠的碳廓清能力、小鼠腹腔巨噬细胞吞噬鸡红细胞能力、半数溶血值、二硝基氟苯诱导的小鼠迟发型变态反应及NK细胞活力（P均<0.05）。结论：植物乳杆菌P-8可通过提高单核-巨噬细胞功能、体液免疫功能、细胞免疫功能及NK细胞活力增强小鼠的免疫功能。     

Functional and safety characterization of autochthonous Lactobacillus paracasei FS103 isolated from sheep cheese and its survival in sheep and cow fermented milks during cold storage

The main objective of this study was to evaluate some probiotic characteristics of Lactobacillus spp. isolated from traditional sheep cheese, and to investigate the fermentative ability and viability in sheep and cow milks of a selected potential probiotic Lactobacillus (L.) strain, i.e., L. paracasei FS103. A total of 54 autochthonous Lactobacillus isolates were characterized for (i) acidity and bile salt resistance, (ii) tolerance to gastric and intestinal juice models, and (iii) antagonistic activity against pathogens and antibiotic resistance. Potential probiotic Lactobacillus has been used in sheep and cow milks for the manufacturing of experimental fermented milks. In these latter, pH value, microbial count, and sensory analysis were carried out. Lactobacillus FS103 classified as L. paracasei subsp. paracasei had a good survival in gastric and intestinal juice models, inhibited the growth of undesirable bacteria, and was susceptible to chloramphenicol, clindamycin, penicillin, amoxicillin, erythromycin, tetracycline, and ampicillin. Moreover, when used to produce experimental sheep and cow fermented milks, L. paracasei FS103 was able to acidify both milk types leading to a continuous pH decrease during all fermentation time (24 h). FS103 population remains viable at a level > 108 CFU mL−1 after 21 days of cold (4 °C) storage. The results of sensory analysis showed that scores related to consistency, taste, and astringent were significantly higher in sheep fermented milk while animal-like was less acceptable compared to cow fermented milk. Lactobacillus paracasei FS103 isolated from sheep cheese exhibited potential probiotic properties and suitable features for sheep and cow fermented milks maintaining high vitality during cold storage.     

西藏灵菇胞外多糖组分对小鼠免疫调节作用及机制的研究

摘要：【目的】研究数均分子量为0.1×105~3.0×105（组分1）及1.8×103（组分2）的西藏灵菇胞外多糖组分对正常小鼠免疫功能的影响,并探讨其影响机制。【方法】依据卫生部保健食品功能学评价程序和检验方法,灌胃给药,剂量分别120 mg/kg体重、80 mg/kg体重、40 mg/kg体重,检测脏器／体重比值、半数溶血值（HC50）、自然杀伤细胞（NK）活性、迟发型变态反应（DTH）、腹腔巨噬细胞吞噬功能。采用免疫印迹法,测定小鼠腹腔巨噬细胞中Erk蛋白及COX-2酶的表达量。【结果】组分1能够明     

松子壳多糖对小鼠主要免疫细胞功能的影响

目的探讨松子壳多糖（pine nut shell polysaccharide,PSP）对小鼠主要免疫细胞的影响。方法应用MTT法测定PSP对小鼠脾淋巴细胞的毒性和对ConA或LPS诱生小鼠脾T、B淋巴细胞的转化,用中性红吞噬试验测定腹腔巨噬细胞的吞噬功能,应用乳酸脱氢酶释放法测定NK细胞的杀伤活性。结果 PSP对脾细胞毒性很低,各种浓度对小鼠脾淋巴细胞的增殖均有较强的促进作用（P〈0.01）;PSP在浓度50～300μg/mL时,明显促进T淋巴细胞的转化（P〈0.01）,但是当浓度达到300μg/mL时表现出一定的抑制作用（P〉0.05）;PSP在25～200μg/mL时显著促进了小鼠脾B淋巴细胞的转化（P〈0.05）,但是当浓度达到300μg/mL时,抑制作用极显著（P〈0.01）;不同浓度均可以增强小鼠腹腔巨噬细胞吞噬中性红的能力及其代谢功能,当浓度在100μg/mL时能显著的促进巨噬细胞吞噬中性红的能力（P〈0.01）;PSP在浓度100～300μg/mL时,能极显著的促进NK细胞对Yac-1的杀伤作用（P〈0.01）,当浓度达到400μg/mL,对NK细胞杀伤性的促进作用开始减弱。结论 PSP对小鼠脾淋巴细胞的毒性较低,能增强免疫细胞活性,有望成为新一代免疫调节剂。     

Comparative Evaluation of Oral Administration of Probiotic Lactobacilli-fermented Milks on Macrophage Function

Six strains of lactobacilli belonging to three species (Lactobacillus casei, Lactobacillus acidophilus and Lactobacillus helveticus) were evaluated for probiotic attributes viz. acid tolerance, bile tolerance and cell surface hydrophobicity. All the six strains exhibited probiotic attributes with considerable degree of variation. Three Lactobacillus strains selected on the basis of probiotic attributes were used for preparing three different fermented milks. In order to evaluate the effect of feeding these probiotic fermented milks on macrophage cell function, an in-vivo trial was conducted in mice for a period of 2, 5 and 8?days. The control group of mice was fed with skim milk. The phagocytic activity of macrophages increased significantly (P?<?0.05) on feeding fermented milk prepared using L. acidophilus, L. casei and L. helveticus as compared to milk group (control) on 2nd, 5th and 8th day of feeding, respectively. Likewise, the release of ??-glucuronidase and ??-galactosidase from peritoneal macrophages increased significantly (P?<?0.05) on 2nd, 5th and 8th day of feeding as compared to their respective control group (milk). The results thus depict that feeding of probiotic fermented milk enhances phagocytic activity of the macrophages.     

Daily ingestion of fermented milk containing Lactobacillus casei DN114001 improves innate defense capacity in healthy middle-aged people

Different lactic acid bacteria have often been administered as a dietary means to enhance immune system activity. Based on this statement, the aim of the current work was to test the effects of a Lactobacillus casei DN114001 fermented milk consumption on the immune response capacity in middle-age volunteers. Forty-five healthy volunteers, 24 women and 21 men (aged: 51-58 years), were randomized into two groups to receive three cups per day of a L. casei DN114001 (10(8)-10(10) ufc/g) fermented milk (n = 23), or placebo (n = 22), during an 8-week period. Measurements were performed before (day 0), and after the nutritional intervention (day 56). After the trial, no changes in immune cell proportions were detected, but the probiotic-treated group increased oxidative burst capacity of monocytes (probiotic group: p = 0.029; placebo group: p = 0.625), as well as NK cells tumoricidal activity (probiotic group: p = 0.023; placebo group: p = 0.125). Results showed that daily intake of fermented milk containing Lactobacillus casei DN114001 could have a positive effect in modulating the innate immune defense in healthy-middle-age people.     

Dominant lactic acid bacteria and their technological properties isolated from the Himalayan ethnic fermented milk products

Ethnic people of the Himalayan regions of India, Nepal, Bhutan and China consume a variety of indigenous fermented milk products made from cows milk as well as yaks milk. These lesser-known ethnic fermented foods are dahi, mohi, chhurpi, somar, philu and shyow. The population of lactic acid bacteria (LAB) ranged from 10(7) to 10(8) cfu/g in these Himalayan milk products. A total of 128 isolates of LAB were isolated from 58 samples of ethnic fermented milk products collected from different places of India, Nepal and Bhutan. Based on phenotypic characterization including API sugar test, the dominant lactic acid bacteria were identified as Lactobacillus bifermentans, Lactobacillus paracasei subsp. pseudoplantarum, Lactobacillus kefir, Lactobacillus hilgardii, Lactobacillus alimentarius, Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris and Enterococcus faecium. LAB produced a wide spectrum of enzymes and showed high galactosidase, leucine-arylamidase and phosphatase activities. They showed antagonistic properties against selected Gram-negative bacteria. None of the strains produced bacteriocin and biogenic amines under the test conditions used. Most strains of LAB coagulated skim milk with a moderate drop in pH. Some strains of LAB showed a high degree of hydrophobicity, suggesting these strains may have useful adhesive potential. This paper is the first report on functional lactic acid bacterial composition in some lesser-known ethnic fermented milk products of the Himalayas.     

Modulation of natural killer activity in mice following infection with Listeria monocytogenes

Mice that received a sublethal, intraperitoneal dose of viable Listeria monocytogenes, virulent strain 10403, exhibited a systemic increase in natural killer (NK) activity. The kinetics of the response differed with respect to the various effector cell populations analyzed. Resident peritoneal cells and peripheral blood leukocytes demonstrated high NK activity on Days 3, 7, and 10. Peak spleen and bone marrow NK activity was observed on Day 3, returning to normal levels by Day 7. In contrast, peritoneal exudate cells, elicited with proteose peptone, expressed enhanced NK activity for 60 days following infection with viable Listeria. Augmented NK activity was detected with all cell types as early as 12 hr after infection. The intraperitoneal injection of nonviable antigenic preparations derived from L. monocytogenes, strain 10403, resulted in the enhancement of peritoneal and splenic NK activity. In contrast, mice that received an intraperitoneal injection of avirulent Listeria, strain 19113, failed to express enhanced levels of NK activity. The genetic trait of anti-listerial resistance which is associated with non-H-2 linked genes was of no importance with respect to enhanced NK activity. Listeria-resistant C57BL/6J and Listeria-susceptible DBA/2J mice both produced systemic augmentation of NK activity following infection. NK activity was not abrogated by macrophage depletion or by treatment with anti-Thy 1.2 serum plus complement. These results confirm the potent immunostimulatory capacity of virulent Listeria for NK activity and provide further insight into the kinetics of this response in various lymphoid compartments. The protracted augmentation of NK activity of elicited peritoneal exudate cells as compared to nonelicited peritoneal cells in Listeria-primed mice suggests that the influx of inflammatory cells may provide NK-enriched and/or accessory populations for immunopotentiation of NK activity in inflammatory sites.