DNA分子标记技术及其在啤酒大麦品种鉴定中的应用

简单对比了常用的大麦品种鉴定方法以及归纳DNA分子标记技术的分类,进一步通过综述几种常用DNA分子标记技术的原理、优缺点及其在大麦品种及纯度鉴定上的应用情况,以期为DNA分子标记在啤酒大麦品种及纯度鉴定研究提供参考。     

RAPD标记在烟草研究中的应用

随机扩增多态DNA(Randomly Amplified Polymorphic DNAs,RAPD)分子标记技术的诞生,为分子生物学技术在农业研究中的应用注入了新的活力,并为传统农业研究向分子水平发展提供了捷径。本文重点综述了RAPD分子标记技术在烟草群体分离分析和鉴定、标记辅助选择、遗传变异的识别、烤烟品种分子指纹分析、黑胚病菌全基因组DNA多态性标记、根结线虫种类鉴定、赤星病菌的分类地位等方面的研究进展,以及这些领域的研究发展和应用前景。      

现代分子生物学技术在益生菌分类鉴定中的应用现状

益生菌（probiotics）又称微生态调节剂，是指能够促进肠内菌群生态平衡，对宿主起有益作用的活的微生物制剂。国内外对益生菌菌种、作用机理均有相当的报道，获得了许多使用益生菌的经验。近些年来。分子生物学特别是基因工程技术的发展为益生菌的研究提供了新的手段。本文主要从益生菌菌株的分类鉴定方面，比较详细地综述了近年来国际上在分子水平上研究益生菌的技术方法。     

DNA分子标记及其在啤酒大麦种质鉴定中的应用

随着分子生物学的快速发展,各种新型分子标记技术也不断涌现,为啤酒大麦的种质鉴定和选育提供了有力依据并取得优良成绩.文中针对常用DNA分子标记技术及其在啤酒大麦图谱构建、种质鉴定和分子标记辅助选择等方面进行了综述,为本领域研究及应用提供一定参考.     

基于Miseq法纳豆冻干粉对小鼠肠道菌群影响的研究

抗生素近年来被滥用,它抑制或杀死微生物使得机体菌群失调。因此找出一种抗生素的安全有效替代物非常有必要,而益生菌是一种有效的替代物。本研究以纳豆冻干粉为原料,正常小鼠和肠道菌群失衡小鼠为动物试验模型,采用体内灌胃试验和Miseq方法研究纳豆冻干粉对小鼠肠道菌群的影响并进行生物信息分析。分析多样本间的肠道菌群多样性和单样本属水平上的分类情况;分析纳豆芽孢杆菌及益生菌、致病菌的菌数变化情况。预期的研究结果为揭示纳豆芽孢杆菌的肠道菌群调节机理提供科学依据,对人类健康和传统发酵食品微生物的开发具有十分重要的意义。     

乳制品中乳酸菌分子鉴定技术进展

该文全面论述了乳制品中乳酸菌分类和鉴定的分子鉴定技术,着重阐述了乳制品中乳酸菌鉴定及多态性研究中的DNA指纹图谱技术、基于rDNA序列的分子标记技术和种间特异性PCR等技术的原理、方法及应用.分子鉴定技术的发展为乳酸菌快速分类和鉴定提供了现代可靠的技术手段.根据不同分子鉴定方法分辨率和检测限的不同,可依据研究目的选择合适的分子方法或分子鉴定与表型鉴定结合的方法更有效快速的进行乳制品中乳酸菌的鉴定.     

肠道菌群与食物过敏性疾病研究进展

食物过敏作为食品安全的热点问题在全球引起了广泛关注,食物过敏发病率的不断增加与肠道菌群结构和功能的变化密切相关。生活环境和膳食结构的改变、抗生素的使用等诸多因素都可引起肠道菌群失衡,而肠道菌群丰度和多样性的变化可导致肠道菌群与宿主免疫系统相互作用的变化,从而破坏口服耐受增加食物过敏的发病率。近年来随着肠道菌群-宿主相互作用等相关研究的不断深入,调整肠道菌群结构为过敏性疾病的防治提供了新的思路,因而益生菌在预防和治疗食物过敏中的作用开始备受关注。本文首先从细胞和分子水平总结了口服耐受和食物过敏的产生的相关机理,进一步综述了目前对于肠道菌群通过与宿主黏膜免疫系统相互作用调节食物过敏的相关机制研究,并探讨益生菌防治食物过敏的潜在机理,以期为益生菌在预防和治疗食物过敏中的应用提供理论依据。     

DNA分子遗传标记技术在仓储害虫中的研究与应用

DNA分子遗传标记的产生和发展,为从分子水平研究重要经济昆虫提供了全新的技术和手段。仓储害虫在农业经济中占有重要地位,通过对仓储害虫遗传物质的研究和分析,能够从生命的本质上探索仓储害虫的系统发育、遗传结构和进化机制等问题,为害虫综合治理策略提供理论支持。在仓储害虫中,分子标记研究起步较晚,研究的重点主要是鞘翅目和啮虫目害虫。回顾、分析了DNA分子标记技术在仓储害虫中的研究与应用,包括仓储害虫种类鉴定、系统发育、种群遗传多样性及抗药性等,并对该技术的研究前景进行了展望。     

23 株酿酒酵母ISSR指纹图谱分析及SCAR标记的建立

目的：构建酿酒酵母菌株的简单重复序列间多态性指纹图谱数据库并建立序列特异性扩增区（sequencecharacterized amplified region,SCAR）标记技术,为酿酒酵母菌株的分类、遗传亲缘关系鉴定及菌种专利保护提供可靠的DNA分子标记技术依据。方法：在简单重复序列间多态性（inter-simple sequence repeat,ISSR）指纹数据分析基础上进行聚类分析并对菌种进行分类鉴定,同时将酿酒酵母菌株9号和15号中扩增获得的ISSR特异性DNA带转化为可以直接用于菌株快速鉴定的SCAR分子标记。结果：构建23 株酿酒酵母的ISSR指纹图谱,并在相似系数为0.85水平上将23 个供试菌株分为3大类,其中,1、2、4、7、15、16、17、19、20、21、23聚为第一类;10、11、12、13、14、18号菌株聚为第二类且10号和11号菌为同一菌株;3、5、6、8、9、22号菌聚为第三类且属于同一菌株。此外,利用所获得的2 个特异性条带成功转化为序列特异性扩增区分子标记。结论：在生产上酿酒酵母菌株遗传背景差异不大,常存在同物异名现象,而采用ISSR指纹及其SCAR分子标记技术快速鉴定酿酒酵母菌株在工业生产上具有重要意义。     

我国益生菌产业发展动态研究进展

益生菌是通过改善肠道微生物平衡或调节宿主黏膜与系统免疫功能的微生物添加物,能够提供机体正常菌群无法提供的生理作用。益生菌因具有提高机体免疫力、维持肠道菌群结构平衡、促进营养物质的消化吸收等功能受到消费者青睐。近年来益生菌产业发展迅速,品种繁多,已经形成了产业规模。本文针对上述情况,对我国益生菌制品的发展现状和存在的问题进行了综述,为我国益生菌制品的研究与发展提供理论依据。     

Probiotics in the new millennium

Beneficial effects on human health by specific probiotic microorganisms such as prevention of gastrointestinal tract infections, immune stimulation, and balancing of the intestinal microflora have been established in numerous clinical trials. The successful probiotic strains, which are mainly members of Lactobacillus and more recently Bifidobacterium naturally found in the human intestinal tract, have been traditionally incorporated into fermented milk products but have excellent potential for further inclusion in functional foods and health-related products. While the health claims are generally accepted by both scientists and consumers, often the molecular mechanisms underlying the probiotic properties remain controversial. Further progress concerning the molecular basis of probiotic traits will give vital reinforcement to the probiotic concept and is a prerequisite for rational development into further applications. In this review, current research on the genetics of properties of the intestinal lactobacilli that may contribute to the activity and effectiveness of probiotics is described. The potential of molecular biology for future probiotic applications is addressed and a probiotic strain developed by modern biotechnology with advantages for specific consumers is presented.     

益生乳酸菌在乳制品中的应用研究进展

益生乳酸菌是一类能利用碳水化合物发酵产生大量乳酸,且对宿主有益的微生物。乳制品在人类膳食结构中占有十分重要的地位,随着消费者对乳品品质和健康要求的提升,具有各种健康功能的益生乳酸菌在乳品中的应用及相关加工技术和功能产品的研发日益受到关注。通过添加益生乳酸菌等活性因子获得功能性乳制品,是增强乳品健康功效的有效方法。本文综述了近年来有关益生乳酸菌在发酵乳、干酪、乳饮料、冰淇淋和奶粉等乳制品中的应用研究现状,重点介绍了益生乳酸菌发挥功能的主要代谢产物酶类和胞外多糖的应用研究,包括在不同乳制品中益生乳酸菌及其产物发挥的作用,常用的益生乳酸菌菌株种类,生产加工过程中存在的主要问题及解决方法,为益生乳酸菌在乳制品中的应用开发提供参考。     

山茱萸中有益菌的分离和鉴定

将药用植物山茱萸作为有益菌的分离源,以获得常见有害菌的抗性菌,提高山茱萸的利用价值。以马铃薯葡萄糖琼脂和营养琼脂平板分离、纯化其体外真菌和细菌,对获得的菌株进行黑曲霉、黄曲霉和大肠杆菌等有害菌的对峙实验,并对抗性菌进行分子生物学和生理生化的种属鉴定。实验结果表明：从山茱萸中分离纯化28株菌（12株细菌、16株真菌）,其中2株菌对黑曲霉、黄曲霉有一定的抑菌效果,经分子生物学和生理生化实验鉴定,菌株S136是肠杆菌属（Enterobacter sp.）、菌株S138是芽孢杆菌属（Bacillus sp.）的细菌。     

潜在益生乳酸菌分离和鉴定研究进展

利用益生菌提高人类健康水平是当前营养健康领域最具前景的方向之一。乳酸菌是食品中常用的益生菌,迄今为止,联合国粮食及农业组织（FAO）和世界卫生组织（WHO）推荐仅从人的胃肠道分离的乳酸菌可在食品中使用。而越来越多的研究从食品来源中分离出具有益生功能的菌株以扩大益生菌的选择范围。随着分子生物学和检测分析等技术的发展,基质辅助激光解吸电离-飞行时间质谱（MALDI-TOF MS）、全基因组测序、实时荧光定量聚合酶链式反应（RT-FQ-PCR）等技术可以鉴定到亚种及菌株水平上的益生菌。鉴于分离鉴定技术是益生菌安全规范应用的先决条件,该文综述了近年来针对潜在益生乳酸菌有效分离和鉴定技术的研究进展,以期为我国益生乳酸菌自主开发利用提供借鉴。     

Molecular approaches to study probiotic bacteria

Functional foods comprising probiotic bacteria are receiving increasing attention from the scientific community and science funding agencies [1]. An essential aspect relating to the functionality of probiotic-based foods is to develop molecular methods to determine the presence, activity and viability of probiotic bacteria in the human gastrointestinal (GI) tract [2]. The GI tract is composed of a complex ecosystem of various microbial habitats colonized by numerous different commensal micro-organisms. This indigenous gut microbiota is essential to the overall health of the host by performing important physiological functions. In particular, they protect against pathogenic bacteria and drive the development of the immune system during neonatal life. Further metabolic activities of the GI microbiota that beneficially affect the host include continued degradation of food components, vitamin production, and production of short chain fatty acids that feed the colonic mucosa. It is clear that factors such as diet, sickness, stress, or medication can result in loss of well-being of the host, and it is assumed that some of these symptoms are due to perturbation of what is termed the normal balance of the gut microbiota. Knowledge of the structure and function of the standard microbiota, and its response to diet, genetic background and lifetime of the host must be taken into account when designing probiotic-based functional foods. The application of molecular techniques for detection and identification of microbes has provided a major breakthrough in the analysis of microbial ecosystems and their function [3]. The successful application and further potential of these molecular methods to study probiotic bacteria and their impact on the standard GI microbiota is discussed below.     

Characterization of homofermentative lactobacilli isolated from kefir grains: potential use as probiotic

Considering that several health promoting properties are associated with kefir consumption and a reliable probiotic product requires a complete identification of the bacterial species, the present work evaluates several proved markers of probiotic potential of eleven isolates of homofermentative lactobacilli isolated from kefir grains and molecular identification and genotypic diversity. Using restriction analysis of amplified ribosomal DNA (ARDRA) and analysis of the 16S-23S rRNA internal spacer region we confirmed that all homofermentative lactobacilli belong to the species Lactobacillus plantarum. RAPD-PCR analysis allowed the discrimination of lactobacilli in five clusters. All isolates exhibited high resistance to bile salt. High survival after one hour of exposure to pH 2.5 was observed in Lb. plantarum CIDCA 8313, 83210, 8327 and 8338. All isolates were hydrophilic and non autoaggregative. Isolate CIDCA 8337 showed the highest percentage of adhesion among strains. All tested lactobacilli had strong inhibitory power against Salmonella typhimurium and Escherichia coli. Seven out of eleven isolates showed inhibition against Sal. enterica and five isolates were effective against Sal. gallinarum. Only CIDCA 8323 and CIDCA 8327 were able to inhibit Sal. sonnei. We did not find any correlation between the five clusters based on RAPD-PCR and the probiotic properties, suggesting that these isolates have unique characteristics.     

Rapid discrimination of Bifidobacterium animalis subspecies by matrix-assisted laser desorption ionization-time of flight mass spectrometry

Currently, the species Bifidobacterium animalis consists of two subspecies, B. animalis subsp. lactis and B. animalis subsp. animalis. Among these two subspecies, B. animalis subsp. lactis is especially important because it is widely used in the manufacture of probiotic dairy products. The application of these microbes in the food industry demands fast, accurate and low cost methods to differentiate between species and strains. Although various genotypic methods have been employed to discriminate between these two subspecies, they are not easily adapted for rapid identification in the industry. The purpose of this study was to evaluate the use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to differentiate between the two subspecies of B. animalis, and for discrimination at strain level. We identified twenty-three strains of B. animalis at subspecies and strain level by genotypic methods and by proteomics using MALDI-TOF MS. The proteomics identification by MALDI-TOF was nearly identical to that obtained by genotypic identification using comparison of tuf and atpD gene sequences, and single-nucleotide polymorphisms (SNPs), insertions, and deletions (INDELs). We identified four protein markers, L1, L2, A1, and A2, which are useful for discriminating between both subspecies. Proteomics identification using MALDI-TOF MS was therefore an accurate method for discriminating and identifying these bacteria. Given the speed in which this method is achieved (~20 min including sample preparation), MALDI-TOF MS is promising as a tool for rapid discrimination of starter cultures and probiotics.