筛选鸡嗉囊降解胆固醇的内源益生菌

目的:益生菌具有降低胆固醇作用,从鸡嗉囊内利用选择性培养基筛选和复选具有降低胆固醇作用的内源益生菌.方法:利用MRS培养基和以胆固醇为碳源的复选培养基分别进行好氧、兼性、厌氧培养,逐层倒平板划线分离,最终分离和筛选出纯的益生菌,观察描述其菌落形态特征和油镜下观察菌株的特征,并进行一系列生化实验,结合伯杰氏细菌鉴定手册初步确定益生菌种类.结果:筛选分离出1株好氧菌、1株兼性菌、1株厌氧菌,分别命名为DG-1、DG-2、DG-3;初步鉴定为乳酸菌属、乳杆菌属、消化链球菌属.结论:该试验方法简单易行,能够有效地从鸡嗉囊中筛选出生长良好的益生菌,为进一步研究内源益生菌降解胆固醇的特性及机理提供帮助.     

降胆固醇乳酸菌的筛选和分析比较

目的比较7株乳酸菌各项生理特性,筛选高效、安全降解胆固醇的益生菌株,为后期开发应用奠定基础。方法对选定菌株依次进行体外降胆固醇、胆盐水解酶(BSH)活力、人工胃肠液及胆盐耐受性、细胞粘附性能的测定和比较,并分析抗生素耐药性和抑制病原菌活性,最后利用16S rRNA基因测序确定细菌种属。结果不同菌株各项生理指标存在差异。其中菌株ZL-2、JQI-7和PC-26的BSH酶活分别为0.010、0.015和0.030 U,可高效清除体外胆固醇,3株菌体外降解胆固醇率在58%以上;并且耐酸、耐胆盐,具备较好的HT--29细胞粘附性,不存在抗生素耐药性,可有效抑制大肠埃希菌、金黄色葡萄球菌、铜绿假单胞菌和阴沟肠杆菌生长。结论菌株ZL-2、JQI-7和PC-26满足降胆固醇益生菌株的生物学特性,可用于进一步研究和开发。     

牙鲆肠道内产蛋白酶菌的分离与筛选

利用酪蛋白培养基和脱脂乳培养基,从健康牙鲆肠道筛选出25株产蛋白酶的益生菌,占健康牙鲆肠道菌群的17.7%,并利用福林-酚试剂法测定其酶活力.结果表明,25株菌具有产蛋白酶酶活力,其中E14、F1、G7和Y2-2株产酶活力特别强,有望成为益生菌在水产养殖上应用.     

N+注入选育黑曲霉益生菌及其突变菌株产酶条件的研究

以益生菌株黑曲霉AN01为材料,经N 多次诱变得突变益生菌株AN03。结果表明,出发益生菌株AN01酸性蛋白酶、纤维素酶和果胶酶的酶活分别由原来的71.6Ug、141.7Ug和264.8Ug相继提高到996.5Ug、940.4Ug和906.5Ug。突变益生菌株AN03经传5代培养,产酶特性稳定。试验还研究了变突变益生菌株AN03最佳产酶条件,培养基为每升含麸皮105g,玉米芯105g,豆粕105g,氯化铵16g,pH5.0。30℃培养4d。     

克氏原螯虾用芽孢杆菌的特性及其安全性评价

为评估克氏原螯虾用产芽孢益生菌的特性和安全,本研究从市售益生菌产品中分离到19株芽孢杆菌属成员.通过测定抗菌活性、产纤维素酶活性、温度对生长影响来评价其益生菌的特性;通过测定芽孢对高温、低pH、胆汁酸盐的耐受、自聚集性和表面疏水性等评价其稳定性;通过溶血活性、抗生素敏感性、小鼠攻毒试验、克氏原螯虾饲养试验等评价其安全性.以抗菌和产纤维素酶活性、低温(15℃)生长快和无溶血活性这四项指标为标准进行筛选,结果表明:只有3株芽孢杆菌(B8,B20,B27)可成为益生菌候选株.在15℃低温时生长迅速、抗菌和产纤维素酶活性高的2株解淀粉芽孢杆菌(B14和B40)有溶血活性,能引起克氏原螯虾的肠炎,并导致肠道菌群中气单胞菌丰度显著上升.因此,在克氏原螯虾用芽孢杆菌益生菌的选择中,不仅要关注益生功能,更要考虑其安全性.本研究结果为芽孢杆菌在动物保护产品中科学评价和合理使用提供参考.     

几株饲用益生菌对体外模拟胃肠道环境的抗逆性评估

目的研究几株益生菌胃肠道环境下的抗逆能力。方法体外模拟正常猪的胃肠道环境,配制人工肠液和人工胃液,将实验室几株饲用益生菌在人工胃液和人工肠液中分别作用4、6 h,每2 h测一次活菌量。结果实验菌株对模拟胃液的耐受性都较强;除乳酸菌A外,其他菌株对模拟肠液的耐受性也较强。结论除乳酸菌A外的几株实验菌种作为饲用益生菌在抵御猪胃肠道的不良环境方面有很大优势。     

芽胞杆菌抗菌活性和纤维素酶活性的测定

目的筛选鸡用益生菌。方法通过牛津杯法、混菌法和DNS分光光度法对从鸡肠道分离的10株芽胞杆菌进行抑菌效果及纤维素酶活性测定。结果编号为Y1、Y5、Y7的3株芽胞杆菌对测试菌具有较好抑菌效果,编号为Y2、Y4、Y5的3株芽胞杆菌具有较高的产酶活性。结论从分离的10株芽胞杆菌中筛选出1株（编号为Y5）兼具较好抑菌效果和较高产酶活性的地衣芽胞杆菌,具有作为饲用益生菌开发的潜能。     

腹泻及其微生态防治的相关进展

益生菌可能对不同病因引起的不同类型的腹泻有预防的疗效.已经成功的通过调查各种各样的益生菌和确立益生菌性质来证明其对健康的益处和预防、治疗(或缓和)腹泻的作用.其它有益生作用的微生物、某些双歧杆菌、肠球菌以及益生菌酵母菌属的酵母菌作为单个株或复合益生菌在其药用方面的价值也得到肯定.本文主要综述了益生菌在腹泻方面的治疗作用和机制.     

益生菌降胆固醇功能研究进展

本文对益生菌在动物及人体上的降胆固醇功能及可能机理进行了综述。益生菌是一类能够对人体健康起到促进作用的活体微生物。现已发现某些乳杆菌、双歧杆菌和肠球菌属的一些菌株具有降低血清胆固醇水平的能力。由于实验动物和人体在生理学上存在差异,因此同一菌株在实验动物和人体上获得的结论可能不同。关于益生菌降胆固醇功能的机理,研究者提出了不同的假说。这些假说包括:(1)益生菌将胆固醇吸收至细胞膜或细胞质中;(2)益生菌将胆固醇吸附到细胞表面;(3)胆固醇和游离胆盐在酸性环境下发生共沉淀;(4)结合胆盐被益生菌的胆盐水解酶水解成了游离胆盐,后者具有较低的溶解度,不易被肠道回收;(5)胆酸被益生菌的荚膜胞外多糖黏附到了细胞表面;(6)益生菌发酵肠道食源性未消化的碳水化合物产生丙酸,后者能够抑制肝脏胆固醇的生物合成,从而导致血清胆固醇水平降低;(7)益生菌通过下调NPC1L1蛋白基因表达来降低小肠细胞对胆固醇的吸收;(8)益生菌抑制胆固醇乳化胶束的形成。这些假说将为我们认识益生菌的降胆固醇机制及潜在降胆固醇功能菌株的筛选提供了依据。     

几株益生菌的体外抗新城疫病毒作用

【目的】探讨益生菌的抗新城疫病毒(NDV)作用并分析其可能的机制。【方法】采用NDV血凝试验和MTT比色法,分别在体外和鸡胚成纤维细胞(CEF)上评价益生菌对NDV血凝价和抑制率的影响。【结果】所选择的5株益生菌及其代谢产物都极显著地降低了NDV的血凝价,而2株致病菌及其代谢产物对NDV的血凝价均没有影响,这一结果说明益生菌可能对NDV具有直接破坏的作用,并且具有菌株特异性。益生菌可以显著地提高CEF对NDV的抑制率,并且这种作用具有量效关系(P0.01)。益生菌与细胞作用后再感染病毒,对NDV抑制率升高的结果反映了益生菌对NDV吸附细胞的阻断作用;从益生菌与病毒同时接入细胞后降低病毒对细胞侵害的现象,可以看出益生菌可能对病毒具有直接破坏作用;在细胞感染病毒后再接入益生菌对NDV抑制率极低的现象说明,病毒感染后益生菌再很难起作用。【结论】益生菌对NDV既具有直接破坏的作用,又可以阻断NDV对细胞的感染、抑制其在细胞内的增殖。     

Probiotics for the skin: a new area of potential application?

AIMS: The current study aimed at assessing, in vitro, the potential use of probiotics for the skin. METHODS AND RESULTS: Propionibacteria were chosen as potential probiotics as they are members of the normal cutaneous microbiota. Dairy strains were chosen because of their documented safe use. Production of anti-microbial substances was assessed, against selected skin pathogens. Only production of organic acids was detected. Two of the tested strains were found to exhibit high adhesion to human keratin, in vitro. Despite this high adhesion, no inhibition of skin pathogen adhesion to human keratin was observed. CONCLUSIONS: The current strains assessed may not be optimal for use as skin probiotics. However, the results of the study show that the methodology works for investigating this kind of application. SIGNIFICANCE AND IMPACT OF THE STUDY: Methods for selecting probiotics for potential application on the skin are presented.     

基质辅助激光解吸电离飞行时间质谱技术作为常见益生菌菌种鉴定辅助工具的研究

目的评价基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)技术用于常见益生菌菌株鉴定及潜在益生菌菌株筛选的可行性。方法利用16S rDNA序列分析在方法学上对MALDI-TOF MS技术的鉴定能力进行研究;通过MALDI-TOF MS技术对现有保藏菌株的鉴定结果研究MALDI-TOF MS技术的鉴定准确性及优越性。结果 MALDI-TOF MS技术具备较16S rDNA序列分析更高的菌株鉴定能力;MALDI-TOF MS技术的鉴定结果准确、稳定。结论 MALDI-TOF MS技术可以作为准确、快速、廉价及可高通量操作的菌株鉴定方法应用于常见益生菌菌株的鉴定及潜在益生菌菌株的筛选。     

2株动物微生态制剂菌的分离鉴定及其生物学特性初步研究

目的从饲料中进行微生物的分离与培养,筛选动物微生态制剂候选菌株。方法利用变性梯度凝胶电泳(DGGE)筛选得到的7株微生物区分为2种菌,经测序确定其为热带假丝酵母和植物乳杆菌;检测了不同pH、温度、胆盐、金属铜和需/厌氧对其生长的影响。结果当pH小于2.5或铜离子高于150 ppm时,植物乳杆菌无法生长,而热带假丝酵母数量略有下降;胆盐和金属离子对2种菌影响较小,42℃培养条件下相对于30℃培养时热带假丝酵母数量下降了6个数量级。结论筛选得到的2株菌具有应用于动物微生态制剂的潜力,为动物微生态制剂候选菌筛选和评价提供了基础数据。     

杭州地区发酵乳制品中乳酸菌发生耐药传播的安全性研究

目的对杭州地区市售发酵乳制品中分离鉴定的乳酸菌进行耐药传播的安全性分析,旨在揭示发酵乳制品中是否存在可传递耐药基因的超级耐药菌。方法自行分离鉴定的耐药乳酸菌,提取质粒并电泳分析是否存在质粒;以耐受叠氮化钠的大肠埃希菌J53作为受体菌进行质粒接合试验;若乳酸菌存在耐药现象,发现存在耐药质粒,且耐药性可通过质粒传播,评定为3级。乳酸菌存在耐药现象,发现存在耐药质粒,但接合试验未能证明耐药性可通过质粒传播,评定为2级。乳酸菌存在耐药现象,但未检测出耐药质粒,评定为1级。结果美丽健产品中分离的双歧杆菌（MLJ-G-2）和乳杆菌（MLJ-G-1）检测出含有质粒,但不会发生耐药转移,三种菌耐药危害等级分别为2、2、1。伊利产品中分离的双歧杆菌（YL-G-3）、乳杆菌（YL-G-1）、嗜热链球菌（YL-Q）检测出含有质粒,但不会发生耐药转移,四种菌耐药危害等级分别为2、2、1、2。味全产品中分离的双歧杆菌（WQ-G-3）、乳杆菌（WQ-G-1）、乳杆菌（WQ-G-2）、嗜热链球菌（WQ-Q）均检测出含有质粒,其中乳杆菌（WQ-G-1）、乳杆菌（WQ-G-2）会发生耐药转移,四种菌耐药危害等级分别为2、3、3、2。光明产品中分离的乳杆菌（GM-G-2）、乳杆菌（GM-G-3）、嗜热链球菌（GMQ）检测出含有质粒,乳杆菌（GM-G-2）会发生耐药转移,四种菌耐药危害等级分别为2、1、3、2。蒙牛产品中只分离的嗜热链球菌（MN-Q）检测出含有质粒,不会发生耐药转移,耐药危害等级为2。结论发酵乳制品中分离所得的乳酸菌81.2%的菌能检测出质粒,耐药性可能与质粒相关,存在潜在的生物安全威胁;18.8%的菌的耐药性可通过质粒接合发生传播,存在直接的生物安全威胁。     

Anti-Adhesion Effects of Lactobacillus Strains on Caco-2 Cells Against Escherichia Coli and Their Application in Ameliorating the Symptoms of Dextran Sulfate Sodium-Induced Colitis in Mice

The beneficial effects of probiotics on ameliorating ulcerative colitis (UC) have attracted much attention in recent years. Nevertheless, the number of these identified probiotics is still limited. In addition, the adhesion abilities of probiotics are considered to be a key determinant for probiotic efficacy. However, the relationship between the adhesion abilities of probiotics and their role in ameliorating UC has been poorly studied to date. This study measured the adhesion abilities of four Lactobacillus strains to Caco-2 cells and their anti-adhesion effects on Caco-2 cells against pathogenic bacteria, as well as their application in ameliorating the symptoms of dextran sulfate sodium-induced UC, and further illustrated the relationship between these two potential probiotic properties of probiotics and their beneficial effects on UC. Results suggested that the adhesion abilities of the four tested Lactobacillus strains exists highly strain-specific and the mechanisms of their anti-adhesion effect on Caco-2 cells against Escherichia coli may be different. Moreover, all these strains had promising effects on ameliorating UC by reducing inflammatory response and improving the intestinal mucosal barrier function, as well as promoting the production of SCFAs. In conclusion, the four tested Lactobacillus strains can be considered as alternative dietary supplements in alleviating UC. In addition, it could be concluded that there is no significant correlation between the adhesion abilities of probiotics and their role in ameliorating UC, which further illustrated that the adhesion properties of probiotics in vitro may not be suitable as the key criterion for screening potential strains with UC-alleviating effects.

     

New <Emphasis Type="Italic">Bacillus subtilis</Emphasis> Strains as Promising Probiotics

The properties of new B. subtilis strains GM2 and GM5, isolated from potato rhizosphere and possessing high antimicrobial activity, were studied. The potential of the strains for their use as probiotics was characterized. The strains were resistant to bile and to a wide range of the ambient pH. B. subtilis strains GM2 and GM5 possessed proteolytic and phytate-hydrolyzing activity and proved to be safe for model animals. The strains were characterized by antagonistic properties against phytopathogenic micromycetes, as well as against pathogenic and opportunistic enterobacteria. B. subtilis GM2 and GM5 were concluded to be promising strains for use as probiotics.     

Exclusion of vanA, vanB and vanC type glycopeptide resistance in strains of Lactobacillus reuteri and Lactobacillus rhamnosus used as probiotics by polymerase chain reaction and hybridization methods

Strains of Lactobacillus reuteri and Lact. rhamnosus are used as probiotics in man and animal. The aim of this study was to determine whether the glycopeptide resistance in these lactobacilli has a similar genetic basis as in enterococci. Five Lact. reuteri strains and one Lact. rhamnosus, as well as four Enterococcus control strains, were probed for the vanA gene cluster, the vanB gene and the vanC gene by PCR and Southern hybridization, and DNA/DNA hybridization. Their resistance and plasmid patterns were also investigated. All Lactobacillus strains were resistant to vancomycin but susceptible to a broad range of antibiotics. Four of the Lactobacillus strains (including the Lact. rhamnosus strain) did not harbour any plasmid and two of them contained five and 6 plasmid bands respectively. None of the Lactobacillus strains possessed the vanA, vanB or vanC gene. These findings indicate that the glycopeptide resistance of the Lactobacillus strains analysed is different from the enterococcal type. The study provides reassurance on the safety of the Lactobacillus strains used as probiotics with regard to their vancomycin resistance.     

Lactic acid bacteria isolated from canine faeces

AIMS: Lactic acid bacteria (LAB) were isolated and sequenced from the faeces of healthy dogs. Five of these strains were selected and further characterized to clarify the potential of these strains as probiotics for canine. METHODS AND RESULTS: LAB were found in 67% (14/21) of the canine faeces samples when plated on Lactobacilli Selective Media without acetic acid. Out of 13 species identified with partial 16S rRNA gene sequencing, Lactobacillus fermentum LAB8, L. mucosae LAB12, L. rhamnosus LAB11, L. salivarius LAB9 and Weissella confusa LAB10 were selected as candidate probiotic strains based on their frequency, quantity in faeces, growth density, acid tolerance and antimicrobial activity. The minimal inhibitory concentration values of these isolates were determined for 14 antibiotics. L. salivarius LAB9, W. confusa LAB10 and L. mucosae LAB12 were viable in pH 2 for 4 h (mLBS), indicating tolerance to acidity and thus the potential to survive in gastrointestinal tract of the canine. The LAB8-LAB12 strains showed antimicrobial activity against Micrococcus luteus A1 NCIMB86166. CONCLUSIONS: Thirteen different LAB species were found from the faecal microbiota of the healthy canines. Five acid tolerant and antimicrobially active LAB strains with the capacity to grow to high densities both aerobically and anaerobically were chosen to serve as candidate probiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: The selected LAB strains are among the first host-specific LAB with antimicrobial activity isolated from canines that could serve as potential probiotics for canine use.     

Fermentation technologies for the production of probiotics with high viability and functionality

There is growing scientific evidence supported by mechanistic and clinical studies that probiotics can provide health benefits. As probiotics are highly sensitive to many environmental factors, and because the propagation of many strains of intestinal origin is not straightforward, most commercial strains are selected on the basis of their technological properties - ruling out some strains with promising health properties. To date, probiotic production has almost exclusively been carried out using conventional batch fermentation and suspended cultures, in some cases combined with the use of sublethal stresses to enhance cell viability, the addition of protectants or microencapsulation to provide cell protection. However, other less conventional fermentation technologies, such as continuous culture and immobilized cell systems, could have potential for enhancing the performance of these fastidious organisms. These technologies might be employed to develop strains with improved physiology and functionality in the gut and to enlarge the range of commercially available probiotics, as well as expanding product applications.