乌鸡和珍珠鸡杂交体血液学指标测定及肠道菌检测

乌鸡和珍珠鸡杂交种—骡鸡各项血液指标与乌鸡无明显差异,细菌检测得知:双歧杆菌(2/12,16.67%)、乳杆菌(3/12,25%)、粪链球菌(5/12,41.67%)、大肠埃希菌(1/12,8.33%)、蜂房哈夫尼菌(1/12,8.33%)是其主要肠道菌。     

双歧杆菌试管内生物拮抗作用研究

目的 本实验从正常青少年体内分离出1株双歧杆菌,通过试管内研究双歧杆菌对大肠埃希菌和粪肠球菌的生物拮抗作用.为双歧杆菌临床应用及食品开发提供一定的基础理论依据和广阔的市场前景.方法 本项研究以从佳木斯大学健康学生体内分离出1株双歧杆菌为试材,将大肠埃希菌、粪肠球菌接种于PYG液体培养基中,37℃厌氧培养48 h,将菌液浓度利用分光光度计法调到2麦氏.将大肠埃希菌对照组分为10支,分离的双歧杆菌+大肠埃希菌组10支,分离的双歧杆菌对照组10支,分离的双歧杆菌+粪肠球菌组10支,粪肠球菌对照组10支,将以上50个试管全部置于厌氧培养箱内37℃培养48 h,将培养好的大肠埃希菌和粪肠球菌进行梯度稀释,然后用微量移液器吸取标本于每个培养基上滴3滴,每滴滴上由高稀释度向低稀释度,液体量为10 μL的菌液.晾干滴种好的培养基于适宜条件进行培养并选出适合菌落生长的稀释度,计算同一稀释度平均菌落数(x).结果 双歧杆菌12 h时对大肠埃希菌生长无显著性,在24h时检测不到大肠埃希菌的存在.12和24h时粪肠球菌与双歧杆菌混合组与粪肠球菌对照组相比,差异均无统计学意义(P＞0.05).结论 体外对照实验研究该双歧杆菌对大肠埃希菌和粪肠球菌的生物拮抗作用,此株双歧杆菌只对大肠埃希菌有抑制作用,而对粪肠球菌无抑制作用,机制需要深入研究.     

抑制猪霍乱沙门氏菌的乳酸菌的分离、鉴定及潜在抑菌物质分析

猪霍乱沙门氏菌(Salmonella choleraesuis)是一种常见的食源性致病菌。为了预防和治疗该菌引起的疾病,饲养者在饲料中大量添加抗生素,致使猪肉存在严重的食品安全问题。从健康成年无量山乌骨鸡肠道内容物中筛选出具有抑菌作用的乳酸菌,测定其对猪霍乱沙门氏菌的抑菌效果,分析乳酸菌抑制猪霍乱沙门氏菌的有效成分,并对筛选的乳酸菌种进行了分子生物学鉴定。采用双层平板法对具有抑制猪霍乱沙门氏菌的乳酸菌进行筛选,采用牛津杯法对抑菌效果进行测定,并采用酶蛋白敏感性测定、热处理、有机酸处理等方法分析抑菌活性物质有效成分,采用16S rDNA分子标记对乳酸菌进行鉴定,并构建系统发育树。结果显示,从健康鸡肠道中筛选出18株乳酸菌,其中2株对猪霍乱沙门氏菌(Salmonella choleraesuis)、大肠埃希菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)、肠炎沙门氏菌(Salmonella enteritidis)、肠炎沙门氏菌亚种(Salmonella enteritidis subspecies)、志贺氏菌(Shigella)、无乳链球菌(Streptococcus agatactiae)具有良好的抑菌效果;不同蛋白酶、pH处理对乳酸菌无细胞培养液抑菌效果均有不同程度的影响,但是经80℃处理的乳酸菌无细胞培养液,其抑菌效果未明显改变。经鉴定,2株乳酸菌分别为植物乳杆菌(Lactobacillus plantarum)和短乳杆菌(Lactobacillus brevis)。从健康成年无量山乌骨鸡肠道内容物中分离得到的植物乳杆菌菌株L2和短乳杆菌菌株L4对猪霍乱沙门氏菌等致病菌具有明显地抑制作用,推测其抑菌有效成分可能为小肽类及有机酸,这对减少抗生素使用,提高猪肉食品的品质与安全性具有一定价值。     

乳酸杆菌细胞裂解物对金黄色葡萄球菌、大肠埃希菌的抑制作用

目的探讨乳杆菌DM8909裂解物在体内外对金黄色葡萄球菌、大肠埃希菌的抑制作用。方法通过对乳杆菌超声波破碎制成裂解物,分别用乳杆菌裂解物原液、裂解物稀释液、发酵上清液、乳杆菌活菌制剂进行体内、体外实验,观察乳杆菌各成分对金黄色葡萄球菌、大肠埃希菌的抑制作用。结果德氏乳酸杆菌裂解物对金黄色葡萄球菌、大肠埃希菌的抑制作用与乳杆菌活菌制剂的抑制作用相近。结论德氏乳酸杆菌裂解物在体内外对金黄色葡萄球菌、大肠埃希菌均有较强的抑制作用。     

长寿老人源产细菌素乳酸菌的筛选与分子生物学鉴定

本研究以124株我国广西巴马百岁以上长寿老人源乳酸菌菌株为试材,采用双层琼脂平板扩散法筛选产细菌素的优良菌株。在排除有机酸、H2O2等的干扰后,菌株B02、B03、B04、B07、B11、B25、B24和B78的发酵上清液对受试的大肠埃希菌、金黄色葡萄球菌等5株指示菌都表现出很强的抑制作用;进一步硫酸铵沉淀、透析及浓缩处理后,其抑菌活性显著增强,同时蛋白酶敏感性试验显示其具有蛋白质性质,这些结果共同确定其为乳酸菌细菌素。最后,通过16S rRNA序列分析鉴定后确定B02为副干酪乳杆菌;B03为植物乳杆菌;B04为动物双歧杆菌;B07为干酪乳杆菌;B11为德氏乳杆菌保加利亚亚种;B24为鼠李糖乳杆菌;B25为粪肠球菌;B78为植物乳杆菌。     

鸡肠源芽胞杆菌的分离、鉴定和抗菌活性

从人工饲养的健康三黄肉鸡的盲肠和大肠中分离出10株芽胞杆菌,对其进行菌落形态观察、革兰染色、芽胞染色和生理生化特性鉴定,确定为枯草芽胞杆菌、地衣芽胞杆菌、蜡状芽胞杆菌、巨大芽胞杆菌、球形芽胞杆菌、短小芽胞杆菌、凝结芽胞杆菌。同时测定了它们对动物病原性大肠埃希菌和链球菌的抑菌活性。其中有9株芽胞杆菌对大肠埃希菌有抑制作用,8株芽胞杆菌对链球菌有抑制作用。结果表明芽胞杆菌分离株Y2、Y3、Y4、Y5、Y6、Y7、Y8具有作为益生菌开发的潜力。     

临沂市奶牛乳房炎病原菌的分离鉴定与药敏试验

目的为弄清临沂市奶牛乳房炎主要病原菌种类及其药物敏感情况,为科学防治本病提供依据。方法采集患乳房炎奶牛的乳样进行细菌分离鉴定,并对主要病原菌做药敏试验。结果从115份乳样中,分离出6种127株病原菌,其中金黄色葡萄球菌46株,占36.22%,无乳链球菌33株,占25.98%,停乳链球菌21株,占16.53%,大肠埃希菌17株,占13.39%,乳房链球菌8株,占6.3%,沙门菌2株,占1.57%;主要病原菌均对头孢喹诺和左氧氟沙星高度敏感。结论临沂市奶牛乳房炎主要致病菌为金黄色葡萄球菌、链球菌和大肠埃希菌。首选药物为头孢喹诺和左氧氟沙星。因此,治疗奶牛乳房炎应通过药敏试验,合理地选择药物。     

具有拮抗无乳链球菌能力乳杆菌的筛选及抑菌特性

目的从罗非鱼(Nile tilapia)肠道中筛选出具有抑菌作用的乳杆菌,测定其对无乳链球菌(Streptococcus agalactiae)的抑菌效果,分析乳杆菌抑制无乳链球菌的有效成分,并利用分子生物学手段对筛选的乳杆菌菌种进行鉴定。方法采用双层平板法对具有抑制无乳链球菌的乳杆菌进行筛选,牛津杯法对抑菌效果进行测定,酶蛋白敏感性测定、热处理、有机酸处理等方法分析抑菌活性物质有效成分,16S rDNA分子标记对乳杆菌进行鉴定。结果从罗非鱼肠道中筛选出14株乳杆菌,其中菌株RS2对无乳链球菌具有明显的抑菌效果;不同蛋白酶种类、pH处理对乳杆菌无细胞培养液均有不同的影响,经80℃处理的乳杆菌无细胞培养液,其抑菌效果未显著改变(t=0.169 2,P=0.873 8)。此外,此株乳杆菌对猪霍乱沙门菌(Salmonella choleraesuis)、大肠埃希菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)和志贺菌(Shigella sp.)等病原菌具有良好的抑制作用。经鉴定,该乳杆菌为植物乳杆菌(Lactobacillus plantarum)。结论从罗非鱼肠道中分离得到的植物乳杆菌菌株RS2对无乳链球菌等致病菌具有一定的抑制作用,推断其抑菌有效成分为细菌素类物质。此项研究对开发抗生素替代产品,提高食品的品质具有一定价值。     

D-氨基葡萄糖寡聚糖对雏鸡生产性能和主要细菌病防治的研究

目的：使用甲壳素、N-6生命素、氨基葡萄糖盐酸盐防治鸡大肠埃希菌病和沙门菌病。方法：用上述3种产品作为饲料调节剂对雏鸡进行增重试验和抗细菌感染试验。结果：与对照组相比,N-6生命素有促进鸡只生长的作用,同时,上述3种产品能有效地预防和治疗由大肠埃希菌和沙门菌引起的混合感染。结论：N-6生命素防治大肠埃希菌病和沙门菌病效果最好,氨基葡萄糖盐酸盐次之。     

高效降解草酸乳酸菌的筛选

尿路结石70%~80%主要由草酸钙结晶构成。人体内的草酸一般通过肠道内微生物降解,经由粪便排出或在泌尿道吸收由尿液排出。本研究对市场上商品化的发酵乳制品、饮料和药品中的乳酸菌进行分离,得到37株菌,包括嗜热链球菌、保加利亚乳杆菌、干酪乳杆菌、鼠李糖乳杆菌、植物乳杆菌、嗜酸乳杆菌、动物双歧杆菌、长双歧杆菌、粪肠球菌、屎肠球菌和乳球菌,并检测这些菌株降解草酸的能力。结果提示,乳酸菌在体外能够有效的降低培养物中的草酸浓度,并筛选出了具有高效降解草酸能力的乳酸菌菌株。有望成为尿石症预防的新措施。     

Conjugal plasmid transfer (pAM beta 1) in Lactobacillus plantarum

The streptococcal plasmid pAM beta 1 (erythromycin resistance) was transferred via conjugation from Streptococcus faecalis to Lactobacillus plantarum and was transferred among L. plantarum strains. Streptococcus sanguis Challis was transformed with pAM beta 1 isolated from these transconjugants, and transformants harboring intact pAM beta 1 could conjugate the plasmid back to L. plantarum.     

Conjugal plasmid transfer (pAM beta 1) in Lactobacillus plantarum.

The streptococcal plasmid pAM beta 1 (erythromycin resistance) was transferred via conjugation from Streptococcus faecalis to Lactobacillus plantarum and was transferred among L. plantarum strains. Streptococcus sanguis Challis was transformed with pAM beta 1 isolated from these transconjugants, and transformants harboring intact pAM beta 1 could conjugate the plasmid back to L. plantarum.     

The range of antigenic specificity of Bifidobacterium peptidoglycan]

The antigenic relationships of Bifidobacterium bifidum 1 peptidoglycans with different strains of this species (LVA-3, 791, GO-4), bifidobacteria of other species (B. adolescentis GO-13, B. breve 79-38, B. lactentis 79-41, B. longum GO-3) and bacteria of remote taxonomic groups (Streptococcus faecalis 6-3. Staphylococcus aureus COM 885, S. epidermidis COM 2124. Lactobacillus plantarum 1, Escherichia coli M-17) were studied on the basis of a highly sensitive test system permitting the registration of normal human antibodies to peptidoglycans. The level of cross reactions with staphylococci and streptococci correspond to intraspecific and antigenic affinity to L. plantarum and E. coli was considerably less pronounced. Copying a number of epitopes of bifidobacteria, S. aureus peptidoglycan seems to possess additional antigenic determinants which participate in the formation of immunological responsiveness in man.     

Fructooligosaccharides metabolism and effect on bacteriocin production in Lactobacillus strains isolated from ensiled corn and molasses

Fructo- (FOS) and galacto-oligosaccharides have been used to promote the growth of probiotics, mainly those from Lactobacillus genus. However, only few reports have evaluated the effect of prebiotics on bacteriocins activity and production. In this work, we characterized the effect of FOS supplementation on the growth, lactic and acetic acids production, and antimicrobial activity of crude extracts obtained from Lactobacillus strains isolated from ensiled corn and molasses. Seven out of 28 isolated Lactobacillus, belonging to Lactobacillus casei, Lactobacillus plantarum, and Lactobacillus brevis, showed antimicrobial activity against Listeria innocua. Among them, the strain L. plantarum LE5 showed antimicrobial activity against Listeria monocytogenes and Enteroccocus faecalis; while the L. plantarum LE27 strain showed antimicrobial effect against L. monocytogenes, E. faecalis, Escherichia coli and Salmonella enteritidis. This antimicrobial activity in most of the cases was obtained only after FOS supplementation. In summary, these results show the feasibility to increase the antimicrobial activity of Lactobacillus bacteriocins by supplementing the growth medium with FOS.     

Transformation of Lactobacillus plantarum with the plasmid pTV1 by electroporation

Abstract Lactobacillus plantarum ATCC 8014 was transformed with pTV1 by electroporation using a modification of a procedure described for Escherichia coli . The plasmid pTV1 which contains the pE194 replicon from Staphylococcus aureus and transposon Tn917 from Streptococcus faecalis was shown to replicate as a high copy number plasmid in L. plantarum , and the two encoded antibiotic resistance traits were expressed. Tn917 transposed with a high frequency into plasmid DNA of L. plantarum as shown by restriction enzyme analysis and Southern hybridization studies. There are no previous reports on transposition in the lactobacilli. This system may prove to be an important tool in further work on the genetics of these organisms.     

Screening of lactic-acid bacteria from South African barley beer for the production of bacteriocin-like compounds

Strains of Lactobacillus paracasei subsp. paracasei (strain ST11BR), L. pentosus (strain ST151BR), L. plantarum (strain ST13BR), and Lactococcus lactis subsp. lactis (strain ST34BR) producing bacteriocin-like peptides were isolated from barley beer produced in the Western, Northern and Eastern provinces of South Africa. The peptides (bacST11BR, bacST151BR, bacST13BR and bacST34BR) lost their activity after treatment with proteinase K, a proteinase, papain, chymotrypsin, trypsin, pepsin and pronase, but not when they were treated with alpha-amylase, suggesting that the peptides are not glycosylated. The peptides inhibited the growth of Lactobacillus casei, L. sakei, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis, but not Enterobacter cloacae, Lactobacillus bulgaricus subsp. delbrueckii, L. plantarum, L. salivarius, Listeria innocua, Staphylococcus aureus, Streptococcus uberis, S. agalactiae, S. caprinus and S. pneumoniae. Peptides bacST11BR and bacST13BR differed from the other 2 peptides by failing to kill Klebsiella pneumoniae and one of the E. coli strains. Peptides were stable after 2 h of incubation at pH 2.0-12.0, and after 90 min at 100 degrees C. When autoclaved (121 degrees C, 20 min), only bacST13BR lost its activity. The bacteriocin-like peptides were produced at a growth temperature of 30 degrees C, but not at 37 degrees C.     

Biodiversity of lactic acid bacteria in Moroccan soft white cheese (Jben)

The bacterial diversity occurring in traditional Moroccan soft white cheese, produced in eight different regions in Morocco, was studied. A total of 164 lactic acid bacteria were isolated, purified and identified by whole-cell protein fingerprinting and rep-PCR genomic fingerprinting. The majority of the strains belonged to the genera Lactobacillus, Lactococcus, Leuconostoc and Enterococcus. Sixteen species were identified: Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus paracasei, Lactobacillus brevis, Lactobacillus buchneri, Lactococcus lactis, Lactococcus garvieae, Lactococcus raffinolactis, Leuconostoc pseudomesenteroides, Leuconostoc mesenteroides, Leuconostoc citreum, Eterococcus durans, Enterococcus faecalis, Enterococcus faecium, Enterococcus saccharominimus and Streptococcus sp.     

抗鸡白痢益生菌株的筛选

利用从健康蛋鸡和肉鸡肠道内分离的菌株以及本实验室保存菌,在体外分别与鸡白痢沙门菌强毒株作用48h后,以涂片染色镜检法和菌落计数法筛选出对鸡白痢沙门菌有抑制作用的5株细菌,即鸡粪肠球菌、鸡非致病性大肠埃希菌、环状芽胞杆菌、酵母菌和乳酸菌,抑制率分别为97.8%、99％、99.9％、98.2％和78％。     

Isolation of bovine intestinal Lactobacillus plantarum and Pediococcus acidilactici with inhibitory activity against Escherichia coli O157 and F5

Aims:  The growth rate of bovine lactic acid bacteria (LAB) in five different culture conditions, and their inhibitory activity against Escherichia coli O157 and F5 in two assays was assessed to identify LAB for potential prophylactic use in cattle.
Methods and Results:  106 bovine-derived faecal/intestinal LAB were tested in vitro for tolerance to pH 2·0, pH 4·0, 0·15% and 0·3% bile, aerobic incubation, and for inhibitory activity against E. coli O157 ( n  = 3) and F5 ( n  = 1). While no LAB grew at pH 2·0, LAB survivability varied between 35% and 100% on the other tests. Exactly 7·6% (8/106) of LAB supernatants inhibited the growth of E. coli in two assays, whereas 6·6% (7/106) of isolates enhanced the growth of all E. coli strains. Partial 16s rRNA gene sequencing of six best isolates (95th percentile) revealed that five were Lactobacillus plantarum and one Pediococcus acidilactici.
Conclusion:  Lactobacillus plantarum with acid/bile and aerobic resistance and inhibitory activity against E. coli O157 and F5 inhabit the intestinal tract of healthy cattle. Some LAB may enhance E. coli growth.
Significance and Impact of the Study:  Lactobacillus plantarum and P. acidilactici are natural plant micro-organisms and studied silage inoculants. Their identification from gastrointestinal samples of healthy cattle is prophylactically promising.