共查询到18条相似文献,搜索用时 328 毫秒
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从传统发酵乳制品中分离到1 株乳酸杆菌,经API 50 CH 细菌鉴定系统和16S rRNA 基因序列分析后鉴定为植物乳杆菌。分析该菌的质粒图谱后发现该菌携带多个质粒,将其中的小质粒pLD1 测序,结果显示该质粒的大小为2112bp,碱基G+C 含量为37.8%,只编码1 个复制蛋白,其中有1 个17bp 的序列重复了13 次。BLAST 发现该质粒同pLP2000 等的同源性在95% 以上,其中复制蛋白同其他质粒存在一些氨基酸差异。pLD1 质粒序列的GenBank 登陆号为NC_012220,并且它可用于构建良好的乳杆菌基因工程载体。 相似文献
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《食品科学》2020,(4)
目的:构建乳酸杆菌的表达载体,对菌株携带的质粒进行序列测定和功能分析,并利用自身带有的质粒系统构建乳酸杆菌的表达系统,对乳酸菌口服疫苗的制备起到积极的促进作用。方法:从植物乳杆菌LP3中提取质粒并进行序列测定和功能分析。通过质粒pLP3复制子,与pCPSP载体的氯霉素基因CmR、pUC19的复制子构建大肠杆菌-乳酸菌穿梭质粒。在穿梭质粒的基础上加上嗜酸乳杆菌的S层蛋白启动子PslpA和绿色荧光蛋白(green fluorescent protein,eGFP)基因,进一步构建乳酸菌表达载体D-pLP3-PslpA-eGFP。结果:从植物乳杆菌LP3中得到一个天然隐蔽性质粒pLP3,该质粒大小为2 017 bp,GC含量为37.48%。基于质粒pLP3,构建了大肠杆菌-乳酸菌穿梭质粒D-pLP3,并成功转化至不同类型乳酸菌,转化效率介于0.3×10~2~1.0×10~3 CFU/μg(DNA质量计)之间。乳酸菌表达载体D-pLP3-PslpA-eGFP转化至植物乳杆菌,成功获得了荧光蛋白的表达。结论:成功构建了乳酸菌表达载体D-pLP3-PslpA,为乳酸菌基因操作提供了新的工具。 相似文献
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植物乳杆菌素是植物乳杆菌产生的一类具有抑菌活性的肽类,可以抑制许多革兰氏阳性菌。作者简述了细菌素的分类、植物乳杆菌素的抑菌范围和抑菌机制,并简要介绍了几种植物乳杆菌素的性质。尽管目前植物乳杆菌素还未被批准作为防腐剂在食品中使用,但植物乳杆菌已被广泛地应用到食品工业中,相信不久的将来植物乳杆菌素作为一类理想的天然食品防腐剂,应用前景将十分广阔。 相似文献
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乳杆菌(Lactobacillus)的质粒不仅决定了乳杆菌的某些性状,还应用于乳杆菌克隆表达载体的构建,是一种珍贵的遗传信息资源。为了调查中国泡菜中的乳杆菌质粒资源,采集了52份中国泡菜样品,采用乳杆菌PCR快速检出技术检出其中的乳杆菌,并用16s rDNA测序验证检出结果,然后提取检出乳杆菌菌株的质粒。结果检出1株清酒乳杆菌(Lactobacillus sakei)和18株植物乳杆菌(Lactobacillus plantarum),乳杆菌检出率为36.5%。检出含质粒的乳杆菌菌株11株,琼脂糖电泳显示有9种质粒谱型,乳杆菌质粒检出率为21.2%,质粒谱型检出率为17.3%。调查结果提示,中国泡菜中蕴藏丰富的乳杆菌质粒资源,值得进行更大规模的调查和研究。 相似文献
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为保护植物乳杆菌的活性以增强乳杆菌在动物肠道内的益生功能,以天然发酵玉米青贮饲料中优良植物乳杆菌作为芯材,乳清蛋白和明胶为壁材,利用喷雾干燥法制成微胶囊,并以植物乳杆菌包埋率为响应值,研究壁材配比、壁材添加量、进风温度、进料量4个因素,进行中心组合实验(Box-Behnken),通过响应面分析对喷雾干燥法制备植物乳杆菌微胶囊条件进行优化。结果表明:最优条件为壁材配比(乳清蛋白与明胶质量比)1:2、壁材添加量22%、进风温度127℃、进料量35%,在此条件下,植物乳杆菌包埋率为62.15%。结论:本研究为应用喷雾干燥法制备植物乳杆菌微胶囊奠定了基础。 相似文献
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目的分析臭味天然发酵食品中常见益生菌种类。方法本实验从臭味天然发酵食品中选取了4种常见益生菌株,并对耐酸耐胆盐能力、抗药性进行了研究。结果 4株益生菌株经16S rDNA分子鉴定为鼠李糖乳杆菌(Lactobacillus rhamnosus)、植物乳杆菌(Lactobacillus plantarum)、嗜酸乳杆菌(Lactobacillus acidophilus)和粪肠球菌(Enterococcus faecium)。嗜酸乳杆菌在pH 4的培养基培养16 h后,其相对OD_(600 nm)值为51.13%,具有较强的耐酸能力。植物乳杆菌在0.3 g/L和0.6 g/L胆盐质量浓度下培养16 h后,其相对OD_(600 nm)值分别为98.88%、66.22%,具有较强的耐胆盐能力。实验结果表明这2株菌的耐药性都低于鼠李糖乳杆菌和粪肠球菌。结论植物乳杆菌、嗜酸乳杆菌为耐酸耐胆盐低耐药性特点的益生菌株。 相似文献
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Sueli T. Van Der Sand William Greenhalf David C. J. Gardner Stephen G. Oliver 《Yeast (Chichester, England)》1995,11(7):641-658
A distributive model has been constructed to describe the maintenance of the native 2 μm and 2 μm-based plasmids in the yeast Saccharomyces cerevisiae. This model includes elements which represent the influence of selection, segregation, replication and amplification on plasmid stability. A computer program has been written in TURBO PASCAL to implement the model and a number of simulation experiments have been carried out. These simulations permitted the choice of a form of the model which is compatible with the available experimental evidence. The form chosen involves an amplification system in which the RAF gene product binds to the Rep1/Rep2 dimer to prevent the latter acting to repress the activity of the FLP gene. At the same time an upper limit (or ‘ceiling’) was imposed on the number of plasmid molecules able to replicate. Maternal bias was accommodated by ‘tagging’ a small proportion of molecules for inheritance by the mother nucleus and these tags being removed (or ‘cleared’) by the Rep1/Rep2 dimers. This final form of the model makes specific predictions about the stability of 2 μm and YEp plasmids in yeast populations and about the distribution of plasmid copy number between cells in such populations. The predictions on stability have been subjected to experimental test and results provide good support for the model. 相似文献
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该研究以公认安全(Generally Recognized as Safe,GRAS)的谷氨酸棒杆菌(Corynebacterium glutamicum)为宿主,构建高产紫色杆菌素的重组菌株。利用谷氨酸棒杆菌天然大质粒pTET3的复制与分配元件,构建了低拷贝质粒pOK12CG1,该质粒在谷氨酸棒杆菌中的拷贝数约为6拷贝/基因组,且与谷氨酸棒杆菌常用质粒pEC-XK99E和pXMJ19兼容。以低拷贝质粒pOK12CG1为骨架构建了携带紫色杆菌素合成操纵子(vioABCDE)的质粒pCGvio,并分别以谷氨酸棒杆菌标准株ATCC 13032和插入序列(Insertion Sequence,IS)元件删除株为宿主,构建了7株合成紫色杆菌素的重组菌株。通过初步筛选,发现基于低拷贝质粒的重组菌株ATCC13032/p CGvio,其紫色杆菌素产量(508.24 mg/L)高于基于中高拷贝质粒的重组菌株ATCC 13032/pECvio(376.16 mg/L),而基于低拷贝质粒的IS元件删除重组菌株ISDM023/pCGvio紫色杆菌素产量达到了610.13mg/L。进一步采用正交实验设计对重... 相似文献
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以实验室前期分离自混合果蔬酵素的植物乳杆菌(Lactobacillus plantarum S)、分离自树莓酵素的植物乳杆菌(L. plantarum WD)和分离自不同奶制品的保加利亚乳杆菌(L. bulgaricus LB-DR)、鼠李糖乳杆菌(L. rhamnosus Lr-05-281)与干酪乳杆菌(L. casei D-400)5株乳酸菌为研究对象,采用平板药敏纸片扩散法、PCR及RT-PCR技术从表型、基因型以及基因表达几个方面分析菌株的抗药性。结果表明5株菌对氨基糖苷类、喹诺酮类、糖肽类抗生素、多粘菌素B均有抗性;对大环内酯类、四环素类、磺胺类抗生素、呋喃妥因均敏感,并有较为相似的耐药谱;而对不同的β-内酰胺类抗生素敏感性不同;5株乳酸菌均含有质粒,供试的12个抗性基因中,在质粒上检测到erm、aph、vanⅠ、aacⅠ4种抗性基因,基因组DNA上检测到aph、erm、vanⅠ、blaⅡ、aacⅠ、aacⅡ6种抗性基因。部分抗性基因在MRS和加抗生素的MRS培养下会表达,不表达的抗性基因在相应抗生素诱导的条件下其抗性基因不表达。L. plantarum WD菌株质粒上因只含一种vanⅠ抗性基因,其应用安全性较好。 相似文献
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Ioanna-Areti Asteri Konstantinos Papadimitriou Effrossyni Boutou Bruno Pot Effie Tsakalidou 《International journal of food microbiology》2010,141(3):222-228
The pLAC1 plasmid of Lactobacillus acidipiscis ACA-DC 1533, a strain isolated from traditional Kopanisti cheese, was characterised. Nucleotide sequence analysis revealed a circular molecule of 3478 bp with a G + C content of 37.2%. Ab initio annotation indicated four putative open reading frames (orfs). orf1 and orf4 were found to encode a replication initiation protein (Rep) and a mobilization protein (Mob), respectively. The deduced products of orf2 and orf3 revealed no significant homology to other known proteins. However, in silico examination of the plasmid sequence supported the existence of a novel operon that includes rep, orf2 and orf3 in pLAC1 and that this operon is highly conserved also in plasmids pLB925A02, pSMA23, pLC88 and pC7. RT-PCR experiments allowed us to verify that these three genes are co-transcribed as a single polycistronic mRNA species. Furthermore, phylogenetic analysis of pLAC1 Rep and Mob proteins demonstrated that they may have derived from different plasmid origins, suggesting that pLAC1 is a product of a modular evolution process. Comparative analysis of full length nucleotide sequences of pLAC1 and related Lactobacillus plasmids showed that pLAC1 shares a very similar replication backbone with pLB925A02, pSMA23 and pLC88. In contrast, mob of pLAC1 was almost identical with the respective gene of plasmids pLAB1000, pLB4 and pPB1. These findings lead to the conclusion that pLAC1 acquired mob probably via an ancestral recombination event. Our overall work highlights the importance of characterizing plasmids deriving from non-starter ‘wild’ isolates in order to better appreciate plasmid divergence and evolution of lactic acid bacteria. 相似文献
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Lactobacillus plantarum N014 is a bacteriocin-producing lactic acid bacteria originally isolated from nham, a traditional Thai fermented sausage, and in the process of development to be used as a starter culture for nham fermentation. During the fermentation process, there is a need to identify the starter culture among several naturally occurring bacteria. In this study, a new plasmid carrying the gfp (green fluorescent protein) gene was constructed based on pGKV210, an Escherichia coli/ Lactococcus shuttle vector containing an erythromycin resistance marker. The gfp gene derived from pGFPuv was placed under the control of an L-lactate dehydrogenase promoter and then inserted at the EcoRI site of pGKV210, leading to pN014-GFP. The novel plasmid was used to transform L. plantarum N014, which is a bacteriocin-producing lactic acid bacteria isolated from nham. The resulting transformant, L. plantarum N014-GFP+, was brightly fluorescent and harbored the expected plasmid. A plasmid stability test revealed that pN014-GFP was stable after 100 generations of growth under nonselective pressure. L. plantarum N014-GFP+ and its parent strain were shown to be very similar in growth rate, bacteriocin production, and lactate production. L. plantarum N014-GFP+ was able to survive in a nham model. The survival clones were still fluorescent and harbored pN014-GFP. 相似文献
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M Fernández A Margolles J E Suárez B Mayo 《International journal of food microbiology》1999,48(2):113-123
Curing of a plasmid that encoded a beta-galactosidase gene (beta-gal) from the Lactobacillus plantarum strain of dairy origin LL441 was not accompanied by complete loss of the lactose utilization phenotype. DNA-DNA hybridization, using an internal fragment of the beta-gal gene as a probe, revealed a second determinant located on the chromosome of the cured derivatives. The chromosomal copy was present in all of a series of beta-Gal+ L. plantarum and Lactobacillus pentosus strains from different origins. In addition, four other L. plantarum strains harboured plasmid encoded beta-gal genes as well. Since both sequences cross-hybridized and present a similar genetic organization, it is postulated that the plasmid copy was generated through gene duplication and, probably, selected by growth of the strains in lactose rich environments. 相似文献