模拟淀粉条件下乳杆菌吸附苯并芘的能力

【目的】研究了模拟淀粉条件下嗜酸乳杆菌(Lactobacillus acidophilus)NCFM、植物乳杆菌(Lactobacillus plantarum)121以及戊糖乳酸菌(Lactobacillus pentosus)ML32吸附苯并芘的能力,为利用乳杆菌去除苯并芘提供一定的理论指导。【方法】基于苯并芘的HPLC检测方法,考察了淀粉含量及类型、培养时间和p H等因素对乳杆菌吸附苯并芘能力的影响,研究了淀粉水解产物及菌体活性影响乳杆菌吸附苯并芘的效果。【结果】淀粉含量在2%–10%的范围内,乳杆菌吸附苯并芘的能力与淀粉含量的增加呈正相关性,且与淀粉种类关系不大,但经糊化处理的淀粉可以促进菌体吸附苯并芘。在模拟淀粉体系中,培养前4 h时乳杆菌吸附苯并芘的效率增长快,此后其吸附率增加缓慢。淀粉经酸性(p H为3–4)和碱性(p H为8–9)处理,乳杆菌吸附苯并芘的能力提升。淀粉的水解产物麦芽糖和葡萄糖都能显著改善乳杆菌吸附苯并芘的能力。与活细胞相比,经灭活处理后乳杆菌细胞吸附苯并芘的能力降低。【结论】在淀粉体系中,乳杆菌依然表现出良好的苯并芘吸附能力,且一定范围内淀粉含量增多、糊化作用以及麦芽糖和葡萄糖的存在可促进其吸附苯并芘的能力。因此,本研究中的乳杆菌或许可以用作生物脱除剂来减少淀粉食物中的苯并芘。     

乳杆菌吸附苯并芘的特性

[目的]探讨植物乳杆菌(Lactobacillus plantarum)121和戊糖乳杆菌(Lactobacillus pentosus)ML32的苯并芘吸附作用与机制.[方法]采用高效液相色谱检测菌体对苯并芘的吸附率.[结果]菌株121和ML32对苯并芘的吸附率分别为65.9%和64.9%,这种吸附特性与菌体活力无关,随培养时间延长、温度提高以及细胞浓度的上升而增加.菌株121和ML32的吸附率在pH 4和5时达到最大,分别为87.6%和89.0%.当培养液中Ca2+或Mg2+浓度大于0.05mol/L时,菌体吸附率与盐离子浓度呈正相关.苯洗脱会导致乳杆菌所吸附的苯并芘减少90%.经碱性蛋白酶、中性蛋白酶、溶菌酶及TCA和SDS等方法处理后,菌体吸附率上升,且不易被苯去除.在胆盐及胃酸环境下,两株菌的吸附率均提高至70%以上,而胰蛋白酶的存在仅对菌株121的吸附率有较大影响.[结论]两株乳杆菌可以通过吸附作用从环境中清除苯并芘,其吸附效果与细菌细胞壁的结构和组成有关.     

植物乳杆菌ZJ8吸附伏马菌素B_1和B_2特性

【目的】研究了植物乳杆菌(Lactobacillus plantarum)ZJ8对伏马菌素B1和B2吸附作用与机制。【方法】采用高效液相色谱检测菌体对FB1和FB2的吸附率。【结果】菌株ZJ8对FB1和FB2的吸附率分别为89.9%、95.0%,这种吸附特性与菌体活力无关,且随培养时间延长而增加。菌株ZJ8的吸附率在p H 4时达到最大,分别为96.4%和99.0%。碱性和高温条件下都不利于菌株吸附伏马菌素。经强酸和SDS处理后,菌体对伏马菌素吸附率显著性上升。菌体细胞壁对FB1和FB2的吸附率高达96.8%和100%。植物乳杆菌ZJ8胞壁成分中肽聚糖的吸附率最高,分别为98.4%和100%。【结论】植物乳杆菌ZJ8可以通过吸附作用清除环境中的伏马菌素B1和B2,对吸附起主要作用的是菌体细胞壁上的肽聚糖。     

乳杆菌吸附塑化剂的影响因素分析及效果评价

【目的】评价嗜酸乳杆菌(Lactobacillus acidophilus) NCFM和类食品乳杆菌(Lactobacillus paralimentarius) 412吸附塑化剂的效果,初步探讨影响其吸附的因素。【方法】基于3种邻苯二甲酸酯类塑化剂：邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)和邻苯二甲酸二乙基己酯(DEHP)的HPLC检测方法,评价了菌株NCFM和412与塑化剂共同温育时的吸附状况,优化菌株吸附DBP的条件,研究菌株在热、酸及NaCl处理后吸附塑化剂的稳定性。【结果】乳杆菌NCFM和412对3种邻苯二甲酸酯类塑化剂均有不同程度的吸附效果,其中菌株NCFM对3种塑化剂DEP、DBP和DEHP的吸附率分别为21.48%、43.32%和9.62%,吸附效果优于菌株412,其中DBP的吸附效果最好。在温度为37 °C时,菌株NCFM吸附DBP的最佳时间是4 h。热、酸和NaCl处理都会显著提高菌体NCFM吸附塑化剂的效果。【结论】嗜酸乳杆菌NCFM通过吸附作用具有清除3种邻苯二甲酸酯类塑化剂的效果,可以作为潜在的塑化剂生物脱除剂使用。     

内蒙古地区传统制作奶豆腐和乌日莫中乳酸菌多样性及分布特征

【背景】传统制作奶豆腐和酸性奶油(乌日莫)是内蒙古农牧地区最喜爱的食品,蕴含着十分丰富的乳酸菌资源,亟待开发利用。【目的】通过解析内蒙古农牧地区传统自制奶豆腐和乌日莫样品中乳酸菌多样性及分布特征,为优良菌株选育与利用提供资源和理论基础。【方法】采用稀释涂布法分离纯化乳酸菌,测定菌株16S rRNA基因序列鉴定种属关系,阐明乳酸菌系统发育、遗传分化及菌群结构。【结果】传统自制样品中共分离得到乳酸菌81株,主要归属于乳酸片球菌(Pediococcus acidilactici)、戊糖片球菌(Pediococcus pentosaceus)、短乳杆菌(Lactobacillus brevis)、瑞士乳杆菌(Lactobacillus helveticus)、副干酪乳杆菌(Lactobacillus paracasei)、食二酸乳杆菌(Lactobacillus diolivorans)、奥塔基乳杆菌(Lactobacillus otakiensis)、植物乳杆菌(Lactobacillus plantarum)、开菲尔乳杆菌(Lactobacillus kefir)、乳酸乳球菌(Lactoc...     

云南泡梨中乳酸菌的分离鉴定及其应用

【背景】泡梨是云南省常见的一种腌渍水果,在云南加工食用已经有一百多年的历史,因其味道酸甜可口、风味独特而深受人们喜爱,而目前对泡梨中微生物种群的系统分析和发酵原理的研究尚未见报道。【目的】研究乳酸菌在云南泡梨中的分布及应用,阐明乳酸菌种类对泡梨发酵中风味物质的影响。【方法】从云南省4个不同地区采集12份泡梨样品,经菌落菌体形态、生理生化特性和16SrRNA基因序列分析进行菌种分离与鉴定。利用分离的乳酸菌为菌种进行泡梨的制备,采用GC-MS技术对人工接种的复合乳酸菌发酵与自然发酵泡梨进行风味物质的分析与感官评价。【结果】分离鉴定出79株植物乳杆菌(Lactobacillus plantarum)、 3株类植物乳杆菌(Lactobacillus paraplantarum)、1株戊糖乳杆菌(Lactobacillus pentosus)、1株干酪乳杆菌(Lactobacillus casei)、2株副干酪乳杆菌(Lactobacillus paracasei)和1株短乳杆菌(Lactobacillus brevis),植物乳杆菌为泡梨发酵中的优势菌。将分离所得乳酸菌用于泡梨制备的结果表明,乳酸菌使泡梨的发酵时间缩短5d且品质更优,分析其中的风味物质发现接种乳酸菌发酵泡梨风味物质更丰富,其中酯类和醇类远多于自然发酵泡梨。【结论】云南泡梨中含有丰富的乳酸菌,选用分离出的优势乳酸菌作为复合乳酸菌用于泡梨发酵获得色泽、口感更好的泡梨,且发酵周期更短,风味物质更丰富。该研究对泡梨制备工艺和进一步标准化生产均具有重要意义。     

不同分离源植物乳杆菌的群体基因组分析

【背景】植物乳杆菌(Lactobacillus plantarum)广泛存在于植物、乳制品、肉制品、哺乳动物和昆虫的肠道等多种生态环境中。【目的】探究不同分离源L. plantarum基因组与其所在环境是否存在潜在的联系。【方法】利用比较基因组学对126株分离自植物、乳制品、肉制品、果蝇及哺乳动物肠道和口腔等部位的L. plantarum菌株基因组进行系统发育分析和功能基因组分析,解析不同分离源菌株间的亲缘关系和进化历程。【结果】果蝇分离株的基因组大小显著高于植物、哺乳动物肠道、肉制品和乳制品分离株(P0.05),植物和哺乳动物肠道、口腔等部位与肉制品分离株的基因组大小和编码基因数量无显著差异(P0.05)。基于单拷贝基因串联和核心基因系统发育树分析均发现,果蝇分离株和乳制品分离株分别集中聚集分布在某一分支中,其余分离源均匀分布在各个分支中。附属基因分析结果与系统发育树分析结果一致。功能基因注释结果发现,果蝇分离株的环境特异性基因参与低聚果糖和几丁质代谢,乳制品分离株的环境特异性基因参与mazEF毒素-抗毒素系统和CRISPR系统。【结论】植物乳杆菌分离株为适应较为独特的果蝇和乳制品生境而发生了适应性进化。本研究为植物乳杆菌适应性进化提供了新见解,同时为解析菌株的进化历程提供了理论基础。     

短乳杆菌与植物乳杆菌的发酵特性

【背景】目前对于酸菜发酵的研究主要关注点是植物乳杆菌(Lactobacillus plantarum),有关短乳杆菌(Lactobacillus brevis)在酸菜方面的研究报道很少。【目的】为了挖掘短乳杆菌的发酵性能并开发酸菜发酵剂,将2株短乳杆菌分别与1株植物乳杆菌进行组合并发酵酸菜,分析短乳杆菌对酸菜发酵品质的影响。【方法】分别测定短乳杆菌与植物乳杆菌的单菌株生长产酸性能、耐酸性及亚硝酸盐降解力,并将两菌种组合后发酵酸菜,分析1-7d内酸度、乳酸菌活菌数、亚硝酸盐含量及酸菜质构特性的变化趋势。【结果】相较于短乳杆菌Lb-9-2,短乳杆菌Lb-5-3的生长和产酸速率较慢、酸耐受力较弱,但其亚硝酸盐降解力较强。两株短乳杆菌分别与植物乳杆菌Lp-9-1组合后产酸力显著增强,并在3 d时达到最低pH值(约3.10);植物乳杆菌Lp-9-1的添加使酸菜中总体乳酸菌生长延迟,在5 d时达到最高活菌数;组合菌种的样品中亚硝酸盐含量在1-7 d内变化较为平缓,前5天内两个组合之间差异不显著;接种乳酸菌会降低酸菜硬度和弹性,发酵3d时Lb-5-3/Lp-9-1组合的硬度最大,感官评价得分最高。【...     

抗生素和高脂饮食对大鼠肠道乳杆菌多样性的影响

【目的】对正常、高脂、抗生素处理大鼠肠道内乳杆菌进行定性和定量分析,比较不同处理组大鼠肠道乳杆菌的多样性。【方法】应用纯培养和非培养技术(16S r RNA基因序列分析、变性梯度凝胶电泳、实时荧光定量PCR)对大鼠肠道乳杆菌进行分离鉴定和多样性分析。【结果】16S r RNA基因序列同源性分析结果显示,正常组大鼠肠道内分离出的乳杆菌包括约氏乳杆菌(Lactobacillus johnsonii)、鼠乳杆菌(Lactobacillus murinus)、嗜酸乳杆菌(Lactobacillus acidophilus)、罗伊氏乳杆菌(Lactobacillus reuteri)、植物乳杆菌(Lactobacillus plantarum)、肠道乳杆菌(Lactobacillus intestinals)、动物乳杆菌(Lactobacillus animalis)和阴道乳杆菌(Lactobacillus vaginalis);但L.animalis在高脂处理组大鼠肠道内未分离到,L.intestinals和L.vaginalis在抗生素处理组大鼠中未分离到。DGGE结果显示3个组别大鼠肠道中乳杆菌构成差异明显,同一组内样品间相似性较高;相较于正常组和高脂组,抗生素组的丰度较差;且正常组大鼠肠道内乳杆菌的多样性高于高脂组和抗生素组。q-PCR结果显示正常组大鼠肠道乳杆菌的数量明显高于高脂组和抗生素组,高脂组的数量也明显高于抗生素组,且3个组别之间存在显著差异(P0.01)。【结论】高脂饮食及抗生素的使用会减少肠道内乳杆菌多样性。     

植物乳植杆菌P-8连续传代过程中遗传稳定性分析

【背景】植物乳植杆菌(Lactiplantibacillus plantarum) P-8是一株具有优良益生特性的乳酸菌,探究其短期连续传代过程中的遗传稳定性对评估其加工生产的稳定性有着重要的指导作用。【目的】研究植物乳植杆菌P-8在37℃恒温环境下、MRS培养基中连续传代100代过程中的遗传稳定性。【方法】在MRS培养基、37℃恒温环境下将植物乳植杆菌P-8连续传代100代,测定不同代菌株(第0、25、50、75和100代)的菌体形态和碳水化合物利用能力,并利用二代、三代测序相结合的技术完成不同代菌株全基因组测序,通过比较基因组学综合分析其在连续传代100代过程中的遗传稳定性。【结果】植物乳植杆菌P-8在连续培养100代过程中,其菌体形态和碳水化合物利用能力均无明显变化。以植物乳植杆菌P-8的原始菌株基因组作为参考,比较分析了不同代菌株的基因组稳定性,发现菌株均有单核苷酸多态性(single nucleotide polymorphism, SNP)位点存在,但数量较少(SNP位点<21个)。不同代菌株基因组共线性良好,具有极高的相似性,且不同代菌株碳水化合物活性酶注释结果无显...     

Extent of genetic lesions of the arginine and pyrimidine biosynthetic pathways in Lactobacillus plantarum,L. paraplantarum,L. pentosus,and L. casei: prevalence of CO(2)-dependent auxotrophs and characterization of deficient arg genes in L. plantarum

Lactic acid bacteria require rich media since, due to mutations in their biosynthetic genes, they are unable to synthesize numerous amino acids and nucleobases. Arginine biosynthesis and pyrimidine biosynthesis have a common intermediate, carbamoyl phosphate (CP), whose synthesis requires CO(2). We investigated the extent of genetic lesions in both the arginine biosynthesis and pyrimidine biosynthesis pathways in a collection of lactobacilli, including 150 strains of Lactobacillus plantarum, 32 strains of L. pentosus, 15 strains of L. paraplantarum, and 10 strains of L. casei. The distribution of prototroph and auxotroph phenotypes varied between species. All L. casei strains, no L. paraplantarum strains, two L. pentosus strains, and seven L. plantarum strains required arginine for growth. Arginine auxotrophs were more frequently found in L. plantarum isolated from milk products than in L. plantarum isolated from fermented plant products or humans; association with dairy products might favor arginine auxotrophy. In L. plantarum the argCJBDF genes were functional in most strains, and when they were inactive, only one gene was mutated in more than one-half of the arginine auxotrophs. Random mutation may have generated these auxotrophs since different arg genes were inactivated (there were single point mutations in three auxotrophs and nonrevertible genetic lesions in four auxotrophs). These data support the hypothesis that lactic acid bacteria evolve by progressively loosing unnecessary genes upon adaptation to specific habitats, with genome evolution towards cumulative DNA degeneration. Although auxotrophy for only uracil was found in one L. pentosus strain, a high CO(2) requirement (HCR) for arginine and pyrimidine was common; it was found in 74 of 207 Lactobacillus strains tested. These HCR auxotrophs may have had their CP cellular pool-related genes altered or deregulated.     

Differentiation of Lactobacillus plantarum, L. pentosus, and L. paraplantarum by recA gene sequence analysis and multiplex PCR assay with recA gene-derived primers

In this study, we succeeded in differentiating Lactobacillus plantarum, Lactobacillus pentosus, and Lactobacillus paraplantarum by means of recA gene sequence comparison. Short homologous regions of about 360 bp were amplified by PCR with degenerate consensus primers, sequenced, and analyzed, and 322 bp were considered for the inference of phylogenetic trees. Phylograms, obtained by parsimony, maximum likelihood, and analysis of data matrices with the neighbor-joining model, were coherent and clearly separated the three species. The validity of the recA gene and RecA protein as phylogenetic markers is discussed. Based on the same sequences, species-specific primers were designed, and a multiplex PCR protocol for the simultaneous distinction of these bacteria was optimized. The sizes of the amplicons were 318 bp for L. plantarum, 218 bp for L. pentosus, and 107 bp for L. paraplantarum. This strategy permitted the unambiguous identification of strains belonging to L. plantarum, L. pentosus, and L. paraplantarum in a single reaction, indicating its applicability to the speciation of isolates of the L. plantarum group.     

Differentiation of Lactobacillus plantarum, L. pentosus and L. paraplantarum species by RAPD-PCR and AFLP

Two high-resolution genotypic techniques (RAPD-PCR and AFLP) were evaluated for their possibility to discriminate the species Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus paraplantarum and to type these taxa at the infra-species level. In total 23 strains of L. plantarum, three strains of L. pentosus, two strains of L. paraplantarum and two related strains for which the species assignment was not clear, were studied. For RAPD-PCR, suitable oligonucleotides and amplification conditions were selected and tested. For AFLP, a double digest of total genomic DNA was used and a subset of restriction fragments was selectively amplified and visualised using different primer combinations. Both methodologies generated, species-specific electrophoretic profiles. Moreover, the presence of distinct subgroups was revealed within the species L. plantarum.     

Lactobacillus paraplantarum sp. now., a new species related to Lactobacillus plantarum

Four strains of facultatively heterofermentative lactobacilli isolated from beer and human feces have physiological characteristics similar to those of Lactobacillus plantarum. Unlike 66% of the L. plantarum strains tested (F. Bringel, M.-C. Curk, and J.-C. Hubert, Int. J. Syst. Bacteriol. 46:588-594, 1996), these strains do not catabolize alpha-methyl-D-mannoside. However, because they exhibit little DNA relatedness to L. plantarum and Lactobacillus pentosus, these four strains were classified as members of a new species, Lactobacillus paraplantarum; strain CNRZ 1885 (= CIP 104668) is the type strain.     

一种快速定量检测益生菌制品中植物乳杆菌的方法

目的建立快速定量检测植物乳杆菌的方法,排除近缘菌的干扰。方法利用SMM系统筛选植物乳杆菌种特异序列,根据特异序列设计引物进行实时荧光定量PCR反应。结果设计的引物具有良好的种特异性,检测限为2．26×10^2CFU／mL。结论该方法快速灵敏,可以在实际生产中应用。     

Isolation of tannin-degrading lactobacilli from humans and fermented foods

Lactobacilli with tannase activity were isolated from human feces and fermented foods. A PCR-based taxonomic assay revealed that the isolates belong to Lactobacillus plantarum, L. paraplantarum, and L. pentosus. Additional studies on a range of Lactobacillus species from established culture collections confirmed that this enzymatic activity is a phenotypic property common to these three species.     

植物乳杆菌LpT1和LpT2体外降胆固醇机制

【目的】初步探讨植物乳杆菌LpT1和LpT2的体外降胆固醇机制。【方法】以MRS、MRS+CH、MRS+CH+S和MRS+CH+N四种培养基为基础,接种植物乳杆菌LpT1和LpT2进行培养,通过分析比较培养基上清液、菌体沉淀和菌体细胞内部胆固醇含量以及接种和未接种两种情况上清液、沉淀和细胞内胆固醇总量变化,推测植物乳杆菌体外降胆固醇机制。【结果】乳酸菌体外降胆固醇存在非代谢和代谢降解两条途径,非代谢途径与共沉淀作用和菌体吸收有关。代谢降解是由于植物乳杆菌在生长过程中产生了特殊的酶系,从而将胆固醇降解成其他物质,导致其含量降低。【结论】研究结果为进一步研究植物乳杆菌体外降胆固醇的机制奠定了良好基础。     

Genome sequence of the naturally plasmid-free Lactobacillus plantarum strain NC8 (CCUG 61730)

Lactobacillus plantarum is a highly versatile lactic acid bacterium found in various ecological niches, such as fermented vegetable, meat, and dairy products and the gastrointestinal tract. We sequenced the genome of L. plantarum NC8, a naturally plasmid-free strain, which has been used as a model strain in many laboratories worldwide.