复方嗜酸乳杆菌片治疗幽门螺杆菌感染的Meta分析

系统评价复方嗜酸乳杆菌片治疗幽门螺杆菌感染的有效性、安全性。

以“复方嗜酸乳杆菌片”“幽门螺杆菌感染”“Compound Eosinophil-Lactobacillus Tablets”“Helicobacter pylori infection”为主题词, 系统检索The Cochrane Library、PubMed、Springer、ProQuest、中国知网、万方和维普等数据库(建库-2020年5月)的随机对照试验文献。利用RevMan 5.3软件对复方嗜酸乳杆菌片的有效性、安全性进行Meta分析。

依据严格的纳入排除标准, 最终纳入18篇随机对照试验文献。Meta分析结果显示: 复方嗜酸乳杆菌片与一线治疗方案联合用药治疗幽门螺杆菌感染临床疗效更优[RR=0.84, 95%CI(0.80, 0.87), P < 0.000 01], 安全性更好[OR=2.83, 95%CI(2.30, 3.49), P < 0.000 01]。进一步亚组分析表明, 复方嗜酸乳杆菌片与四联疗法联合用药治疗幽门螺杆菌感染与四联疗法相比, 临床疗效更优[RR=0.88, 95%CI(0.83, 0.93), P < 0.000 01], 安全性更优[OR=2.58, 95%CI(1.92, 3.48), P < 0.000 01];复方嗜酸乳杆菌片联合三联疗法治疗幽门螺杆菌感染较三联疗法临床疗效更优[RR=0.81, 95%CI(0.76, 0.85), P < 0.000 01], 且安全性好[OR=3.09, 95%CI(2.31, 4.14), P < 0.000 01]。

基于现有文献, 在治疗幽门螺杆菌感染时, 复方嗜酸乳杆菌片与四联疗法或三联疗法联合用药具有一定的临床优势, 能提高幽门螺杆菌根除率, 降低不良反应发生率, 提高安全性。

     

子宫微生物研究及其对IVF-ET助孕患者妊娠结局的影响

分析体外受精-胚胎移植(IVF-ET)患者的子宫微生物对妊娠结局的影响, 并探讨影响子宫微生物群分布的因素。

选取2019年10月-12月在北部战区总医院生殖医学中心行IVF-ET治疗的139例患者为研究对象。入组患者均于移植手术前做阴道微生态检查。术后从移植导管尖端及外鞘配对获取患者的子宫内膜液和宫颈粘液进行微生物培养, 采用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)鉴定宫腔和宫颈微生物。根据质谱法微生物鉴定结果并按优势菌是否为乳杆菌属菌群进行分组, 即乳杆菌属主导组, 非乳杆菌属主导组和鉴定阴性组。

宫腔和宫颈菌属分布一致性尚可(Kappa=0.494)。人绒毛膜促性腺激素(HCG)阳性率在宫腔和宫颈均表现为非乳杆菌属主导组显著低于乳杆菌属主导组(60.0%vs87.2%, P < 0.017;65.7%vs 97.9%, P < 0.017)。着床率及临床妊娠率均在宫腔表现为非乳杆菌属主导组显著低于乳杆菌属主导组(44.7%vs 68.6%, P < 0.017;52.0%vs 83.0%, P < 0.017)。宫颈微生物描述着床率及临床妊娠率差异无统计学意义(P > 0.017)。宫腔中检出乳杆菌属的患者其临床妊娠率显著高于未检出者(83.0%vs 65.2%, P < 0.017)。移植日阴道微生态状况与E2水平是子宫微生物群分布差异的影响因素。

当宫腔微生物以非乳杆菌属为主导时, IVF-ET助孕患者的HCG阳性率、着床率和临床妊娠率显著降低。移植日阴道微生态失调或E2过高可能增加子宫非乳杆菌属检出的风险。

     

基于16S rDNA与1H NMR技术探讨高脂血症兔肠道菌群和代谢物变化

观察高脂血症模型兔的代谢物与肠道微生物变化并分析其相互关系。

雄性新西兰兔16只,随机分为正常组和模型组,每组8只。正常组喂普通饲料,模型组高胆固醇饮食。12周后比较2组兔血脂水平。利用16S rDNA测序技术检测兔粪便肠道菌群变化,采用¹H NMR代谢组学分析结肠代谢物改变。

与正常组比较,模型组兔血清LDL-C、TG、TC水平显著升高（均P＜0.01）;模型组兔肠道菌群结构发生改变,厚壁菌门、Lachnospiraceae_NK4A136_group、un_f_Lachnospiraceae、Subdoligranulum等菌群丰度上升,Lachnospiraceae_NK4B4_ group、un_o_Gastranaerophilales等菌属丰度下降。2组差异代谢物通路分析主要涉及谷氨酰胺与谷氨酸代谢,丙氨酸、天冬氨酸和谷氨酸代谢,磷脂代谢。Lachnospiraceae_NK4A136_group、un_f_Lachnospiraceae、un_o_Gastranaerophilales等菌属与差异代谢物有较强相关性。

高脂血症的病理过程可能通过Lachnospiraceae_NK4A136_group、un_f_Lachnospiraceae、Lachnospiraceae_NK4B4_group、un_o_Gastranaerophilales等菌属参与胆碱类代谢,谷氨酰胺与丙氨酸代谢,导致血脂代谢异常。

     

双歧杆菌乳杆菌三联活菌片对幽门螺杆菌根治后消化道不良反应的改善作用

探讨加用双歧杆菌乳杆菌三联活菌片对临床四联疗法根除幽门螺杆菌(H.pylori)过程中患者消化道不良反应的改善作用。

选择2019年1月至2020年1月在昆明医科大学第二附属医院门诊就诊的100例H.pylori感染患者, 分为益生菌组和正常组, 各50例。全部患者通过四联疗法根除H.pylori后, 益生菌组患者继续加用双歧杆菌乳杆菌三联活菌片治疗, 对结果进行分析。

2组患者使用含有铋剂的四联疗法根除H.pylori后效果满意。益生菌组患者不良反应发生率低于正常组(25.5% vs 47.5%;χ²=11.023, P=0.001)。

益生菌可减轻四联疗法根除H.pylori后消化道不良反应, 根除H.pylori过程中加用益生菌的时机尚待进一步探讨。

     

摔跤运动员赛前集训控体重对肠道菌群及其代谢物的影响

探究赛前集训控体重对高水平摔跤运动员肠道菌群及代谢物的影响。

招募某省摔跤队运动员11名,在赛前集训期前后测量身体成分、收集粪便样本,采用16S rRNA基因测序技术检测肠道微生物的分布和丰度,利用非靶向代谢组学分析微生物的差异代谢产物及其所富集的功能。

摔跤运动员赛前集训后体重显著降低（P＜0.05）,但肌肉含量无显著差异。微生物组结果显示,控体重前后男女运动员肠道菌群alpha多样性和beta多样性均无显著差异。男性运动员Intestinibacter丰度显著增高（P＜0.05）,且与体重、四肢骨骼肌指数变化量呈正相关。代谢组学分析结果显示,男性运动员菌群差异代谢物富集于硫代谢和主要胆汁酸代谢相关通路,女性运动员菌群差异代谢物富集于神经活性配体—受体交互相关信号通路;Intestinibacter丰度变化与胆汁酸7alpha-hydroxy-3-oxo-4-cholestenoate变化呈正相关。

赛前集训控体重未影响摔跤运动员肠道菌群生物多样性和整体物种构成,但可以改变男性摔跤运动员肠道菌群中产丁酸盐菌属的相对丰度,整体表现为运动员肠道菌群对控体重过程较为适应。

     

孕晚期女性阴道菌群与妊娠结局的相关性

分析不同妊娠结局女性孕晚期阴道菌群,探索阴道菌群变化与妊娠结局的相关性。

收集厦门市第五医院收治的妊娠期女性阴道分泌物,筛选排除后,纳入不良妊娠组14例,正常妊娠组17例。采用高通量测序法对阴道菌群16S rDNA V3−V4区进行测序;采用QIIME2软件分析阴道菌群的组成和多样性指标;采用PCoA主坐标分析菌群β多样性差异;采用LEfSe比较不同妊娠结局女性阴道微生物差异,获得具有统计学意义的菌群标志物,并对差异菌群做相关性分析。

在菌群组成方面,厚壁菌门、乳杆菌属比例在正常妊娠组中显著增加,放线菌门、双歧杆菌属比例在不良妊娠组中显著升高（均P＜0.05）。在多样性方面,两组的α多样性差异无统计学意义（P＞0.05）,正常妊娠组β多样性较高,不良妊娠组的菌群相似度较高（均P＜0.05）。LEfSe分析结果显示,正常妊娠组阴道乳杆菌属丰度显著升高,不良妊娠组加德纳菌属、双歧杆菌属和梭菌目丰度显著增加。相关性分析表明,乳杆菌目与梭菌目比例呈负相关。

与正常妊娠组相比,不良妊娠组女性阴道菌群存在多样性下降、乳杆菌丰度下降的趋势,同时双歧杆菌、加德纳菌、梭菌等厌氧菌丰度增加。

     

红茶对2型糖尿病小鼠肠道菌群分布的影响

探讨红茶对2型糖尿病（T2DM）小鼠肠道菌群分布的影响,为研究红茶在代谢性疾病的辅助治疗机制提供参考。

构建 T2DM小鼠模型,将其随机分为模型组（T2DM组）和茶水饲喂组（T2DM_T组）,取健康小鼠作为对照组（Control组）,每组各15只。实验终点收集3组小鼠粪便进行宏基因组测序,分析组间菌群差异;同时进行肝脏组织形态学检查,观察组织病理学改变。

与Control组和T2DM组相比,T2DM_T组拟杆菌门（F = 21.056,P＜0.001）、邓肯氏菌属（F = 13.330,P = 0.001）、乳杆菌属（F = 36.546,P＜0.001）和粘液乳杆菌属（F = 43.813,P＜0.001）的相对丰度增加,担子菌门（F = 8.676,P = 0.005）、Muribaculum（F = 8.151,P = 0.006）和肠球菌属（F = 4.271,P = 0.040）的相对丰度降低。与T2DM组小鼠相比,T2DM_T组小鼠肝细胞排列较为紧密,细胞空泡变性程度有所减弱。

红茶在一定范围内能调节T2DM模型小鼠肠道菌群结构和相对丰度,红茶水喂饲可减缓造模所致的T2DM小鼠肝脏细胞的损伤,其具体作用机制值得深入研究和探讨。

     

杀菌型副干酪乳酪杆菌N1115发酵乳饮品对小鼠免疫功能的影响

研究杀菌型副干酪乳酪杆菌N1115（Lacticaseibacillus paracasei N1115）发酵乳饮品对小鼠免疫脏器指数、免疫球蛋白、巨噬细胞、NK细胞、B淋巴细胞及T淋巴细胞的影响。

将SPF级6～8周龄雄性Balb/c小鼠随机分为对照组以及杀菌型副干酪乳酪杆菌N1115发酵乳饮品低、中、高剂量组,每组15只,连续灌胃30 d,进行免疫脏器指数测定、免疫球蛋白测定、碳廓清能力测定、腹腔巨噬细胞吞噬鸡红细胞实验、NK细胞活性测定、脾淋巴细胞转化实验、迟发型变态反应、血清溶血素测定和抗体细胞生成实验。

杀菌型副干酪乳酪杆菌N1115发酵乳饮品低、中、高剂量组的小鼠碳廓清指数显著高于对照组（t = 3.926 2,P = 0.000 7;t = 6.000 1,P＜0.000 1;t = 5.314 4,P＜0.000 1）,腹腔巨噬细胞吞噬鸡红细胞的吞噬率显著高于对照组（t = 3.812 1,P = 0.001 5;t = 4.257 2,P = 0.000 4;t = 4.976 3,P = 0.000 5）。

杀菌型副干酪乳酪杆菌N1115发酵乳饮品具有增强小鼠非特异性免疫力的功能,可为副干酪乳酪杆菌N1115的开发利用提供科学依据。

     

黄连素和黄芩苷不同配伍对肠道细菌体外生长的影响

研究不同配伍的黄连素和黄芩苷在模拟肠道厌氧环境下对肠道内有害菌、条件致病菌和益生菌体外生长的影响。

采用微量肉汤稀释法测定黄连素和黄芩苷不同配伍对肠道内金黄色葡萄球菌、沙门菌、肠炎链球菌、大肠埃希菌、乳杆菌及嗜黏蛋白阿克曼菌体外生长24 h后吸光度的影响。

对于金黄色葡萄球菌,抑制作用最强的是黄连素∶黄芩苷 = 10∶1（组合六）125 μg/mL（t = –39.350,P＜0.001）,抑制率为99.91%;对于沙门菌,抑制作用最强的是黄连素∶黄芩苷 = 100∶1（组合七）250 μg/mL（t = –73.788,P＜0.001）,抑制率为80.47%;对于肠炎链球菌,抑制作用最强的是黄连素∶黄芩苷 = 1∶0（组合一）250 μg/mL（t = –57.549,P＜0.001）;对于大肠埃希菌,抑制作用最强的是黄连素∶黄芩苷 = 1∶0（组合一）125 μg/mL（t = –29.085,P＜0.001）;对于乳杆菌,增殖作用最强的是黄连素∶黄芩苷 = 100∶1（组合七）31.25 μg/mL（t = 76.280,P＜0.001）;对于嗜黏蛋白阿克曼菌,增殖作用最强的是黄连素∶黄芩苷 = 100∶1（组合七）62.5 μg/mL（t = 8.357,P＜0.001）。

黄连素∶黄芩苷 = 10∶1（组合六）、黄连素∶黄芩苷 = 100∶1（组合七）对有害菌的抑制作用更强,黄连素∶黄芩苷 = 100∶1（组合七）对益生菌的增殖作用更强,而黄连素和黄芩苷联合使用对条件致病菌的抑制作用较弱。

     

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。

     

Bacteriocin production and resistance to drugs are advantageous features for Lactobacillus acidophilus La-14, a potential probiotic strain

L. acidophilus La-14 produces bacteriocin active against L. monocytogenes ScottA (1600 AU/ml) in MRS broth at 30°C or 37°C. The bacteriocin proved inhibitory to different serological types of Listeria spp. Antimicrobial activity was completely lost after treatment of the cell-free supernatant with proteolytic enzymes. Addition of bacteriocin produced by L. acidophilus La-14 to a 3 h-old culture of L. monocytogenes ScottA repressed cell growth in the following 8h. Treatment of stationary phase cells of L. monocytogenes ScottA (107-108 CFU/ml) by the bacteriocin resulted in growth inhibition. Growth of L. acidophilus La-14 was not inhibited by commercial drugs from different generic groups, including nonsteroidal anti-inflammatory drugs (NSAID) containing diclofenac potassium or ibuprofen arginine. Only one non-antibiotic drug tested, Atlansil (an antiarrhythmic agent), had an inhibitory effect on L. acidophilus La-14 with MIC of 2.5 mg/ml. L. acidophilus La-14 was not affected by drugs containing sodium or potassium diclofenac. L. acidophilus La-14 shows a good resistance to several drugs and may be applied in combination for therapeutic use.     

Molecular characterization of antimicrobial compound produced by Lactobacillus acidophilus AA11

Approximately 63 strains of Lactobacillus acidophilus were isolated from Egyptian home-made cheese and examined for production of antagonism. Only eight strains demonstrated inhibitory activity against spoilage microorganisms (i.e. Staphylococcus aureus and Bacillus cereus) and pathogens (i.e. E. coli, Salmonella sp. and Shigella sp.). Lactobacillus acidophilus AA11 produced higher antimicrobial activity with a wide range of inhibition. The agent AA11 was sensitive to proteolytic enzymes and retained full activity after 30 min at 100 degrees C. Activity against sensitive cells was bactericidal but not bacteriolytic. The compound was produced during growth phase and could be extracted from the culture supernatant fluids with n-butanol. 12% SDS-PAGE analysis of 40% ammonium sulphate precipitated agent showed two peptides with molecular weights of approximately 36 kDa and approximately 29 kDa. No plasmid was identified in Lactobacillus acidophilus AA11 indicating that the genes encoding the inhibitory agent were located on the chromosome. These characteristics identify the inhibitory substance as a bacteriocin, designated acidocin AA11 and confer the agent an application potential as a biopreservative.     

Production kinetics of acidophilin 801, a bacteriocin produced by Lactobacillus acidophilus IBB 801

Lactobacillus acidophilus IBB 801 produces a small bacteriocin, designated acidophilin 801. Studying the relationship between growth and bacteriocin biosynthesis revealed primary metabolite kinetics of bacteriocin production with a peak activity at the end of the exponential growth phase followed by a decrease during the stationary phase. Both microbial growth and bacteriocin production was inhibited by lactic acid. Whereas volumetric bacteriocin production (activity units (AU) ml(-1)) was favoured under pH-controlled conditions, bacteriocin titres rapidly decreased because of strong adsorption of the bacteriocin molecules to the producing cells under less acidic conditions.     

Antimicrobial activity of lactobacilli: preliminary characterization and optimization of production of acidocin B, a novel bacteriocin produced by Lactobacillus acidophilus M46

Approximately 1000 lactobacillus strains were isolated and screened for the production of antimicrobial activity, using a target panel of spoilage organisms and pathogens. Only eight positive strains were found; two of these were studied in more detail. Lactobacillus salivarius M7 produces the new broad spectrum bacteriocin salivaricin B which inhibits the growth of Listeria monocytogenes, Bacillus cereus, Brochothrix thermosphacta, Enterococcus faecalis and many lactobacilli. A new atypical bacteriocin produced by Lact. acidophilus M46, acidocin B, combines the inhibition of Clostridium sporogenes with a very narrow activity spectrum within the genus Lactobacillus and was selected for further characterization. Acidocin B is sensitive to trypsin, heat-stable (80°C for 20 min) and can be extracted from the culture supernatant fluid with butanol. Native acidocin B occurs as a large molecular weight complex (100 kDa), while with SDS-PAGE the partly purified activity migrates as a peptide of 2·4 kDa. Optimization of the cultivation conditions resulted in an eightfold increase of the amount of acidocin B produced during growth. Growth is not necessary for acidocin B production; washed producer cells can synthesize the bacteriocin in a chemically defined production medium. The application potential of acidocin B is discussed.     

体外拮抗幽门螺杆菌的人嗜酸乳杆菌菌株的选育

目的 探讨人嗜酸乳杆菌对幽门螺杆菌（Ｈｅｌｉｃｏｂａｃｔｅｒ ｐｙｌｏｒｉ,ＨＰ）毒力株的体外拮抗作用,筛选出对ＨＰ毒力株有明显拮抗作用的嗜酸乳杆菌菌株。方法 从健康人胃肠道中分离出５２株嗜酸乳杆菌可疑株,通过其培养特性,生理特性,生化反应及代谢产物测定等进行鉴定,获得２６株嗜酸乳杆菌。同时,从临床患者胃活检标本中分离出２３株ＨＰ菌株,用ＰＣＲ方法筛选出ｃａｇＡ阳性ＨＰ毒力株,然后,采用打孔法进行嗜酸乳杆菌培养上清拮抗ＨＰ毒力株的实验,以１％的乳酸作对照。结果 筛选出４株对ＨＰ毒力株有明显拮抗作用的嗜酸乳杆菌,这种拮抗作用不依赖嗜酸乳杆菌分泌的乳酸。结论 人嗜酸乳杆菌在体外对ＨＰ毒力株具有明显拮抗作用。该研究为应用微生态疗法治疗ＨＰ感染提供了理论基础。     

Partial purification and characterization of the bacteriocin produced by Lactobacillus acidophilus YIT 0154

One strain of Lactobacillus acidophilus was found to produce a bacteriocin-like substance in the culture filtrate. The substance was produced in a growth-associated manner, showed heat stability at neutral and acidic pH and exhibited antibacterial activity against various species of Lactobacillus including L. acidophilus itself. The molecular weight of the substance was in the range of 6.2-95 kDa. N-terminal amino acid sequence analysis suggests that the substance may belong to class IIb bacteriocin.     

Purification and characterization of a bacteriocin produced by Lactobacillus acidophilus IBB 801

Lactobacillus acidophilus IBB 801 produces a small bacteriocin, designated acidophilin 801, with an estimated molecular mass of less than 6.5 kDa. It displays a narrow inhibitory spectrum (only related lactobacilli but including the Gram-negative pathogenic bacteria Escherichia coli Row and Salmonella panama 1467) with a bactericidal activity. The antimicrobial activity of cell-free culture supernatant fluid was insensitive to catalase but sensitive to proteolytic enzymes such as trypsin, proteinase K and pronase, heat-stable (30 min at 121 degrees C), and maintained in a wide pH range. The proteinaceous compound was isolated from cell-free culture supernatant fluid and purified. Crude bacteriocin was isolated as a floating pellicle after ammonium sulphate precipitation (40% saturation) and partially purified by extraction/precipitation with chloroform/methanol (2/1, v/v). Further purification to homogeneity was performed by reversed phase Fast Performance Liquid Chromatography. The amino acid composition was determined. Amino acid sequencing revealed that the N-terminal end was blocked.     

Cloning, phenotypic expression, and DNA sequence of the gene for lactacin F, an antimicrobial peptide produced by Lactobacillus spp

Lactacin F is a heat-stable bacteriocin produced by Lactobacillus acidophilus 11088. A 63-mer oligonucleotide probe deduced from the N-terminal lactacin F amino acid sequence was used to clone the putative laf structural gene from plasmid DNA of a lactacin F-producing transconjugant, L. acidophilus T143. One clone, NCK360, harbored a recombinant plasmid, pTRK160, which contained a 2.2-kb EcoRI fragment of the size expected from hybridization experiments. An Escherichia coli-L. acidophilus shuttle vector was constructed, and a subclone (pTRK162) containing the 2.2-kb EcoRI fragment was introduced by electroporation into two lactacin F-negative strains, L. acidophilus 89 and 88-C. Lactobacillus transformants containing pTRK162 expressed lactacin F activity and immunity. Bacteriocin produced by the transformants exhibited an inhibitory spectrum and heat stability identical to those of the wild-type bacteriocin. An 873-bp region of the 2.2-kb fragment was sequenced by using a 20-mer degenerate lactacin F-specific primer to initiate sequencing from within the lactacin F structural gene. Analysis of the resulting sequence identified an open reading frame which could encode a protein of 75 amino acids. The 25 N-terminal amino acids for lactacin F were identified within the open reading frame along with an N-terminal extension, possibly a signal sequence. The lactacin F N-terminal sequence, through the remainder of the open reading frame (57 amino acids; 6.3 kDa), correlated extremely well with composition analyses of purified lactacin F which also predicted a size of 51 to 56 amino acid residues. Molecular characterization of lactacin F identified a small hydrophobic peptide that may be representative of a common bacteriocin class in lactic acid bacteria.     

嗜酸乳杆菌SR-1产类细菌素发酵条件及生物学特性的研究

本研究通过正交试验获得嗜酸乳杆菌sR-1分泌类细菌素的最适培养条件,即葡萄搪2％,大豆蛋白胨2．5％,酵母粉0．4％,血浆蛋白2．5％。并首次利用流加培养的方式,改进了类细菌素产生菌的发酵条件,抑菌直径从19mm提高到25mm,同时对类细菌素生物学特性进行了初步的探索。结果表明：嗜酸乳杆菌产生的类细菌素对多种蛋白酶不敏感,在低pH下能抑制革兰阴性、阳性的致病菌,在pH6．5下吸附菌体作用最强。     

Determining the Suitability of Lactobacilli Antifungal Metabolites for Inhibiting Mould Growth

Summary In recent years, public concern about indoor mould growth has increased dramatically in the United States. In this study, lactic acid bacteria (LAB), which are known to produce antimicrobial compounds important in the biopreservation of food, were evaluated to determine if the same antimicrobial properties can be used to inhibit mould fungi that typically colonize wood. Based on biomass measurement, cell-free supernatants from Lactobacillus casei subsp. rhamnosus and Lactobacillus acidophilus grown in deMan Rogosa Sharpe (MRS) broth inhibited 95–100% growth of three mould fungi and one stain fungus associated with wood-based building materials. Lactic acid and four unknown compounds ⩽ kDa molecular weight were fractionated from the culture supernatant by thin layer chromatography and high-performance liquid chromatography. Antifungal activity, which was attributed to one or more unknown metabolites, was retained during heating and neutralization. A 1:2 dilution of L. casei supernatant inhibited 100% growth of all test fungi.