双歧酸奶定量干燥菌种的实验室研究

目的:对双歧酸奶定量干燥菌种的实验室研究进行初步探讨.方法:培养收获三种乳酸菌(双歧杆菌、乳杆菌、嗜热链球菌),并采用真空冷冻干燥技术进行处理,从而对干燥效果以及常温保存活性进行评价和分析.结果:三种乳酸菌的干燥菌粉活菌计数均大于1012个/g;凝乳试验显示次代菌种发酵时间明显低于第一代;混合发酵的凝乳中活菌计数均大于106个/ml,单一菌种发酵的凝乳中活菌计数超过1010个/ml;干燥菌种在37℃放置30 d后,活菌数仍可达108个/g以上.结论:双歧酸奶定量干燥菌种实验室研究结果令人满意,为开发双歧酸奶袋装式干燥菌种打下了基础.     

双歧杆菌四联活菌片体外生物拮抗作用的研究

目的实验通过双歧杆菌四联活菌片(思连康)对肠道致病菌体外生物拮抗作用的研究,揭示此药治疗腹泻等疾病的作用机制,为临床应用提供科学依据。方法对组成药物的4株益生菌发酵培养,定时取样,检测活菌数与pH值。先分别单独培养大肠埃希菌、沙门氏菌、志贺氏菌、思连康活菌片,调整菌液浓度,然后将思连康与每一个致病菌的菌液共同接种于GAM肉汤,并将每种菌液单独接种作为对照组,厌氧培养,定时检测致病菌与双歧杆菌的活菌数并分析。结果思连康4株菌株发酵终点活菌数均在109 CFU/mL以上,发酵过程中3株原籍菌的pH值逐渐下降,蜡样芽孢杆菌pH值先下降后升高。思连康与致病菌共培养6h,思连康显著影响大肠埃希菌生长(P0.05),而对沙门氏菌和志贺氏菌的生长无影响(P0.05);共培养12h,思连康对3株致病菌均产生明显抑菌作用(P0.05);共培养24h,未检测到致病菌的存在(P0.01)。结论双歧杆菌四联活菌片对致病菌抑制作用强。     

大豆多糖对双歧杆菌及人肠道菌群生长的影响

目的研究大豆多糖对双歧杆菌及肠道菌群生长的影响。方法替换Bs培养基中的碳源,分为不加糖、加葡萄糖2％、加大豆多糖2％、加大豆多糖5％、加低聚果糖2％五组,加3种双歧杆菌（长双歧、青春双歧、两歧双歧）菌液1％,测其24h后的活菌数,比较大豆多糖对双歧杆菌生长的影响;替换Bs培养基中的碳源,分为不加糖、加葡萄糖2％、加大豆多糖2％,加低聚果糖2％四组,加人体粪便菌液1％,模拟人体肠道环境厌氧培养24h后,用选择性培养基测其肠杆菌、肠球菌、双歧杆菌、乳酸杆菌的活菌数,观察大豆多糖对人体肠道菌群的影响。结果大豆多糖添加量为5％时对长双歧的促进作用明显优于不加糖组（P〈0．05）;大豆多糖对人体肠道各菌群的生长促进作用与低聚果糖差异无显著性（P〉0．05）。结论大豆多糖对长双歧杆菌的体外促进作用较明显;以粪菌群发酵糖试验表明,大豆多糖对乳杆菌和双歧杆菌均有促进作用,和低聚果糖作用效果相比差异无显著性（P〉0．05）,具有益生元的特性。     

酷酸梭菌——婴儿型双歧杆菌二联活菌制剂对人体肠道菌群的调节试验

目的 观察酷酸梭菌－－婴儿型双歧杆菌二联活菌制剂对受试人群肠道菌群的影响。方法 检测受试者服用前后的肠道菌群并计数。结果 肠杆菌、肠球菌、拟杆菌的数量无明显变化,双歧杆菌、乳杆菌的数量明显增加,差异有非常显著性（Ｐ〈０．０１）,结论 酪酸梭菌－－婴儿型双歧杆菌二联活菌制剂具有一定的调节人体肠道菌群、增殖双歧杆菌和乳杆菌的作用。     

酪酸梭菌--婴儿型双歧杆菌二联活菌制剂对人体肠道菌群的调节试验

目的　观察酪酸梭菌——婴儿型双歧杆菌二联活菌制剂对受试人群肠道菌群的影响。方法　检测受试者服用前后的肠道菌群并计数。结果　肠杆菌、肠球菌、拟杆菌的数量无明显变化 ,双歧杆菌、乳杆菌的数量明显增加 ,差异有非常显著性 (P<0 .0 1) ,结论　酪酸梭菌——婴儿型双歧杆菌二联活菌制剂具有一定的调节人体肠道菌群、增殖双歧杆菌和乳杆菌的作用。     

双歧杆菌菌液保留灌肠治疗小儿腹泻初探

本文就婴儿双歧杆菌菌液保留灌肠对小儿腹泻的治疗作用进行了初步观察。结果发现,31例试验组患儿治疗后,其大便双歧杆菌活菌计数及革兰氏阳性菌比例均较治疗前和对照组明显升高。提示双歧杆菌菌液保留灌肠对小儿腹泻有治疗作用。     

灭活双歧杆菌调整小鼠抗生素相关性菌群失调

目的：观察灭活的双歧杆菌及其耗尽培养上清液（SCS）对小鼠肠道生理菌群的影响。方法：应用腹腔注射青霉素造成肠菌群失调动物模型,分别以灭活的双歧杆菌菌液,耗尽培养上清液以及活菌菌液对菌群失调小鼠进行灌胃治疗。结果：活菌组、死菌组及SCS组同自然恢复组的肠道生理菌群相比差异均有显著性,死菌组与SCS组相比,差异也有显著性。结论：灭活的双歧杆菌及其SCS对小鼠肠道菌群失调的恢复具有调整作用,尤其对双歧杆菌和乳酸杆菌有更明显的扶持作用。     

玉米低聚糖对双歧杆菌增殖与发酵的影响

目的研究玉米低聚糖对双歧杆菌增殖和发酵的影响。方法试验I组以乳糖替代正常TPY培养基中葡萄糖作为碳源,试验II组以玉米低聚糖替代TPY培养基中的葡萄糖作为唯一碳源,分别在接种培养0、12、24、36、48和72h对两组双歧杆菌活菌数量、培养液中还原糖含量和培养液pH值进行测定。同时以不同剂量玉米低聚糖饲喂小鼠,分析对小鼠粪便中双歧杆菌数量的影响。结果培养72h后,试验II组双歧杆菌活菌数显著高于试验I组(t=5.832,P0.05)。试验II组培养液中葡萄糖含量在12、24、36、48和72h时均较试验I组显著偏高(P0.05)。试验II组培养液中pH在24h之后一直显著低于试验I组(P0.05)。试验I组、II组小鼠粪便中双歧杆菌数量显著高于饲喂前(t=20.109、22.982,P0.05);试验III组小鼠粪便中双歧杆菌数量较饲喂前显著降低(t=4.692,P0.05)。结论玉米低聚糖能够显著促进双歧杆菌体外增殖,增强发酵,并能提高小鼠肠道中双歧杆菌的数量。     

酪酸菌对肠道有益菌的增殖作用和共生关系研究

目的通过体外液体培养证明,酪酸菌能与双歧杆菌、嗜酸乳杆菌和粪链球菌这些肠道有益菌共生.方法在双歧杆菌、嗜酸乳杆菌和粪链球菌的培养基中,加入1/3比例的酪酸菌发酵提取物,进行室温培养24 h.结果3种菌的活菌含量分别比对照组提高了24.00%、42.57%和6.76%.结论表明酪酸菌对肠道有益菌具有增殖作用.     

双歧杆菌对小鼠肠道树突状细胞数量的影响

目的研究双歧杆菌对小鼠肠道树突状细胞(dendritic ce ll,DC)数量的影响。方法分别采用活双歧杆菌菌液(1×109CFU/m l)、灭活双歧杆菌菌液(1×109CFU/m l)、双歧杆菌耗尽培养上清(Spen t cu lturesupernatan t,SCS)、无菌生理盐水给BALB/c小鼠灌胃,均为0.5 m l/(只.d),连续7 d,取小肠空、回肠段,SP免疫组织化学法分析检测肠道DC数量。结果DC分布于整个空、回肠的黏膜固有层。细胞大小不一,外形不规则,胞核外形亦不规则,多数呈偏心位,且DC有不规则突起,与周围细胞有紧密的接触。计数发现,双歧杆菌灌胃后小鼠小肠黏膜固有层DC数量增加(P<0.05),以活菌作用最明显,死菌次之,培养上清作用最弱,经统计学处理差异有显著性(P<0.05)。结论外源性双歧杆菌能增加小鼠小肠黏膜固有层中DC的数量,活菌作用最明显。提示双歧杆菌通过胃肠道途径可能影响DC的分化、发育;对DC的作用可能就是双歧杆菌影响机体免疫功能的重要环节;且保持活菌状态对机体免疫有重要作用。     

Protective effect of bifidus milk on the experimental infection with Salmonella enteritidis subsp. typhimurium in conventional and gnotobiotic mice

The ability of Bifidobacterium bifidum from a commercial bifidus milk to antagonize Salmonella enteritidis subsp. typhimurium in vivo, and to reduce the pathological consequences for the host, was determined using conventional and gnotobiotic mice. Conventional animals received daily, by gavage, 0.1 ml bifidus milk containing about 10(9) cfu B. bifidum and germ-free animals received a single 0.1 ml dose. The conventional and gnotobiotic groups were challenged orally with 10(2) cfu of the pathogenic bacteria 5 and/or 10 d after the beginning of treatment. Control groups were treated with milk. Bifidus milk protected both animal models against the challenge with the pathogenic bacteria, as demonstrated by survival and histopathological data. However, to obtain the protective effect in gnotobiotic animals, the treatment had to be initiated 10 d before the challenge. In experimental and control gnotobiotic mice, Salm. enteritidis subsp. typhimurium became similarly established at levels ranging from 10(8) to 10(9) viable cells g-1 of faeces and remained at these high levels until the animals died or were sacrificed. It was concluded that the protection against Salm. enteritidis subsp. typhimurium observed in conventional and gnotobiotic mice treated with bifidus milk was not due to the reduction of the intestinal populations of the pathogenic bacteria.     

Brazilian Kefir-Fermented Sheep’s Milk,a Source of Antimicrobial and Antioxidant Peptides

Fermented milks are a source of bioactive peptides and may be considered as functional foods. Among these, sheep’s milk fermented with kefir has not been widely studied and its most relevant properties need to be more thoroughly characterized. This research study is set out to investigate and evaluate the antioxidant and antimicrobial properties of peptides from fermented sheep’s milk in Brazil when produced by using kefir. For this, the chemical and microbiological composition of the sheep’s milk before and after the fermentation was evaluated. The changes in the fermented milk and the peptides extracted before the fermentation and in the fermented milk during its shelf life were verified. The antimicrobial and antioxidant activities of the peptides from the fermented milk were evaluated and identified according to the literature. The physicochemical properties and mineral profile of the fermented milk were like those of fresh milk. The peptide extract presented antimicrobial activity and it was detected that 13 of the 46 peptides were able to inhibit the growth of pathogenic microorganisms. A high antioxidant activity was observed in the peptides extracted from fermented milk (3.125 mg/mL) on the 28th day of storage. Two fractions displayed efficient radical scavenging properties by DPPH and ABTS methods. At least 11 peptides distributed in the different fractions were identified by tandem mass spectrometry. This sheep’s milk fermented by Brazilian kefir grains, which has antioxidant and antimicrobial activities and probiotic microorganisms, is a good candidate for further investigation as a source for bioactive peptides. The fermentation process was thus a means by which to produce potential bioactive peptides.     

Effect of Milk Whey and Its Fermentation Products by Lactic Acid Bacteria on Mitochondrial Lipid Peroxide and Hepatic Injury in Bile Duct-ligated Rats

The study was carried out to assess whether bovine milk whey and its products fermented by lactic acid bacteria could ameliorate the lipid peroxidation of hepatic mitochondria associated with cholestatic liver injury due to bile duct ligation. Rats were maintained on one of five diets for 3 weeks before being operated upon and killed 3 weeks after bile duct ligation. The diets included one deficient in vitamin E (control diet) and others supplemented with either 5% milk whey or 5% milk whey fermented with Bifidobacterium longum (B. longum), Lactobacillus acidophilus (L. acidophilus), and Streptococcus salivarius subsp. thermophillus (S. thermophillus). Bile duct-ligated rats, compared with sham-operated rats, had higher organ weights (liver and spleen), higher serum alkaline phosphatase activity, higher serum bilirubin concentration, and higher content of hepatic mitochondrial lipid hydroperoxide. The rats fed on diets containing milk whey fermented with B. longum ameliorated the elevation of organ weights, enzyme activity, bilirubin concentration, and content of mitochondrial lipid hydroperoxide. Milk whey and milk whey fermented with L. acidophilus and S. thermophillus also suppressed the elevation of mitochondrial lipid hydroperoxide, but had no ameliorating effects on organ weights, enzyme activity, and bilirubin concentration. The elevation of serum lipid hydroperoxide was ameliorated in rats fed on diets containing milk whey and milk whey fermented with B. longum and S. thermophillus. The reduction in plasma α-tocopherol due to bile duct ligation was ameliorated in those rats fed on diets containing milk whey fermented with B. longum as well as by S. themophillus. These results suggest that a milk whey fermented with lactic acid bacteria exerts a beneficial effect on free radical-mediated hepatic injury.     

临床微生物检验和细菌耐药性监测探析

目的：探讨临床微生物检验和细菌耐药性监测。方法：对临床分离出的致病菌的耐药情况以及敏感性进行回顾分析,检查出各种病菌对各类抗菌药物的敏感率和耐药率,本文以葡萄球菌属、肠杆菌科、非发酵菌的代表菌种的耐药性和敏感性为例。结果：通过选取金黄色葡萄球菌、表皮葡萄球菌、溶血葡萄球菌、大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌、鲍曼不动杆菌为例进行回顾分析,它们对抗菌药物的耐药率、敏感率具体情况如文中表格所示。结论：临床病原菌的耐药性问题不容忽视,治疗时要根据药物的敏感性和耐药性选择适当的抗菌药物,合理使用抗菌药物,减轻抗菌药物的耐药寿命。     

五倍子提取物抑菌效果及稳定性研究

采用琼脂打孔法和平板涂布法,观察五倍子提取物对常见致病菌的抑菌效果,并以金黄色葡萄球菌、大肠杆菌的抑菌环直径为参考指标,考察紫外光照时间、温度及介质pH值对五倍子提取物抑菌活性的影响。结果表明,五倍子提取物对革兰氏阳性菌的抑菌效果明显强于革兰氏阴性菌,在稳定性研究过程中发现,光照时间、温度及介质pH值对五倍子提取物的抑菌效果影响较大,因此在选用五倍子提取物作植物抑菌剂时应现配现用。     

In vitro inhibition of Helicobacter pylori NCTC 11637 by organic acids and lactic acid bacteria

In this Study the effects of both pH and organic acids on Helicobacter pylori NCTC 11637 were tested. Lactobacillus acidophilus, Lact. casei, Lact. bulgaricus, Pediococcus pentosaceus and Bifidobacterium bifidus were assayed for their lactic acid production, pH and inhibition of H. pylori growth. A standard antimicrobial plate well diffusion assay was employed to examine inhibitory effects. Lactic, acetic and hydrochloric acids demonstrated inhibition of H. pylori growth in a concentration-dependent manner with the lactic acid demonstrating the greatest inhibition. This inhibition was due both to the pH of the solution and its concentration. Six strains of Lact. acidophilus and one strain of Lact. casei subsp. rhamnosus inhibited H. pylori growth where as Bifidobacterium bifidus, Ped. pentosaceus and Lact. bulgaricus did not. Concentrations of lactic acid produced by these strains ranged from 50 to 156 mmol 1⁻¹ and correlated with H. pylori inhibition. The role of probiotic organisms and their metabolic by-products in the eradication of H. pylori in vivo remains to be determined.     

Doxycycline-Dependent Inducible and Reversible RNA Interference Mediated by a Single Lentivirus Vector

Most fermented milk prepared by strains of Lactobacillus helveticus showed significant antihypertensive effect in spontaneously hypertensive rats (SHR) by oral administration. However, milk fermented by other species of lactic acid bacteria did not show significant antihypertensive effects. Most of the whey fractions of the milk fermented by L. helveticus or Lactobacillus delbrueckii subsp. bulgaricus showed higher angiotensin I-converting enzyme (ACE) inhibitory activity than the activity of milk fermented by other species. Proteolytic activity in cell wall and peptide content of the fermented milk were higher in L. helveticus strains than other species.     

Novel putative galactose operon involving lacto-N-biose phosphorylase in Bifidobacterium longum

A lacto-N-biose phosphorylase (LNBP) was purified from the cell extract of Bifidobacterium bifidum. Its N-terminal and internal amino acid sequences were homologous with those of the hypothetical protein of Bifidobacterium longum NCC2705 encoded by the BL1641 gene. The homologous gene of the type strain B. longum JCM1217, lnpA, was expressed in Escherichia coli to confirm that it encoded LNBP. No significant identity was found with any proteins with known function, indicating that LNBP should be classified in a new family. The lnpA gene is located in a novel putative operon for galactose metabolism that does not contain a galactokinase gene. The operon seems to be involved in intestinal colonization by bifidobacteria mediated by metabolism of mucin sugars. In addition, it may also resolve the question of the nature of the bifidus factor in human milk as the lacto-N-biose structure found in milk oligosaccharides.     

Comparative Growth Behaviour and Biofunctionality of Lactic Acid Bacteria During Fermentation of Soy Milk and Bovine Milk

The study reports the growth, acidification and proteolysis of eight selected lactic acid bacteria in skim and soy milk. Angiotensin-converting enzyme inhibition and antimicrobial profiles of skim and soy milk fermented by the lactic acid bacteria were also determined. Among eight lactic cultures (S. thermophilus MD2, L. helveticus V3, L. rhamnosus NS6, L. rhamnosus NS4, L. bulgaricus NCDC 09, L. acidophilus NCDC 15, L. acidophilus NCDC 298 and L. helveticus NCDC 292) studied, L. bulgaricus NCDC 09 and S. thermophilus MD2 decreased the pH of skim and soy milk in greater extent. Acid production (i.e. titratable acidity) by L. bulgaricus NCDC 09 and L. helveticus V3 was higher than other strains. Higher viable counts were observed in S. thermophilus MD2 and L. helveticus V3. Higher proteolysis was exhibited by S. thermophilus MD2 and L. rhamnosus NS6 in both skim and soy milk. Milk fermented by S. thermophilus (MD2) exhibited highest angiotensin-converting enzyme inhibition. Antimicrobial activities of cell-free supernatant of milk fermented by S. thermophilus MD2 and L. helveticus V3 were higher. All the tested lactic acid bacteria performed better in skim milk as compared to soy milk.     

Antimicrobial activity of Myrtus communis L. water-ethanol extract against meat spoilage strains of Brochothrix thermosphacta and Pseudomonas fragi in vitro and in meat

The antimicrobial activity of hydro-alcoholic extract of Myrtus communis L. was investigate in vitro and in situ against different meat spoilage biotypes of Pseudomonas fragi and Brochothrix thermosphacta. Water-ethanol myrtle extract (WEME) was prepared from myrtle leaves and used to study the antimicrobial activity, Minimum Inhibitory Concentration (MIC) and Minimum Lethal Concentration (MLC). Naturally contaminated ground beef was used to evaluate in situ antibacterial activity of freeze-dried myrtle extract at different concentrations. In vitro antimicrobial activity of WEME was significantly more effective against B. thermosphacta than P. fragi strains. MIC and MLC values were in the range of 12.5–50 and 25–100 mg DM/ml, respectively, for B. thermosphacta and P. fragi strains. In situ results showed that the microbial population, except for Pseudomonas spp., decreased significantly in ground meat with added 5 % of freeze-dried myrtle extract. In conclusion, the findings demonstrate the effectiveness of myrtle extract to control or prevent the proliferation of meat spoilage bacteria.