双歧杆菌分类、生理功能及应用研究进展

双歧杆菌在维持机体肠道微生态平衡、抑制致病菌入侵和定植、调节机体免疫能力、降低胆固醇含量等机体健康方面发挥重要作用,拥有广泛的应用前景。介绍了双歧杆菌的分类及分布情况,综述了双歧杆菌的生理功能及在保健食品、普通食品、医药、动物饲料中的应用现状和开发情况,分析了双歧杆菌制剂研究存在的问题,并探讨了其发展前景。     

双歧杆菌的厌氧机理及其基因调控

自从 18 99年法国学者 Tissier发现双歧杆菌以来 ,至今已有 10 0多年历史。研究表明 ,双歧杆菌是人体肠道菌群的重要组成部分 ,是人体肠道中主要的生理性细菌。有关双歧杆菌的生理功能的研究已经有很多的报道 ,也取得了巨大的研究成果。然而 ,由于双歧杆菌是专性厌氧的、革兰阳性细菌 ,对营养要求比较严格 ,生产操作比较困难 ,极大地限制了它在食品中的应用。目前对双歧杆菌的分子生物学研究比较滞后 ,双歧杆菌的厌氧机理还不是十分清楚 ,因此制约了从分子水平上对双歧杆菌进行研究。本文就双歧杆菌的厌氧机理和基因调控方面的最新研究情况…     

双歧杆菌中胆盐水解酶的研究进展

胆盐水解酶的特性及生理功能已成为研究热点。我们探讨了国内外关于双歧杆菌中胆盐水解酶的生化特性、降胆固醇机理及其生理作用几个方面的研究进展,以期对研究双歧杆菌胆盐水解酶,以及双歧杆菌及其制品的开发利用有一定的指导意义。     

双歧杆菌的生物学特性及对人体的生理功能

双歧杆菌（Bifidobacterium）是一种革兰氏阳性菌,具有革兰氏阳性菌典型的生理特征。研究发现,双歧杆菌作为一种生理性有益菌,对人体健康具有生物屏障、营养作用、抗肿瘤作用、免疫增强作用、改善胃肠道功能、抗衰等多种重要的生理功能。     

双歧杆菌的分子生物学研究进展

双歧杆菌是一种有重要生理功能的益生菌,近年逐渐成为微生态领域研究的热点,现对其生理、生化方面的研究已较成熟。随着研究深入,分子生物学又成为该菌的研究重点。本文从其基因组、质粒、分型鉴定、基因工程等方面,介绍双歧杆菌的分子生物学研究进展。     

双歧杆菌的生物学特性及对人体的生理功能*

双歧杆菌 (Bifidobacterium)是一种革兰氏阳性菌 ,具有革兰氏阳性菌典型的生理特征。研究发现 ,双歧杆菌作为一种生理性有益菌 ,对人体健康具有生物屏障、营养作用、抗肿瘤作用、免疫增强作用、改善胃肠道功能、抗衰老等多种重要的生理功能。     

双歧杆菌降胆固醇的作用机制

双歧杆菌是现在食品药品市场被广泛应用的一种菌株,它生理功能的优势及对人体的益处被人们认可。尤其是其在脂类代谢中的降胆固醇功能在各种研究中均得以证实。本研究就双歧杆菌的降胆固醇机制及具有此功能的双歧杆菌产品等方面进行论述,为今后对双歧杆菌的研究提供参考及思路。     

双歧杆菌对裸鼠腹腔巨噬细胞NO形成的调节作用

给裸小鼠腹腔注射青春型双歧杆菌,每天一次,连续５天,以Ｇｒｉｅｓ试剂测定了裸鼠腹腔巨噬细胞分泌ＮＯ的含量。结果表明：双歧杆菌注射组其腹腔巨噬细胞产生ＮＯ的量显著高于对照组,具有显著的统计学意义（Ｐ＜００１）。提示青春型双歧杆菌可激活巨噬细胞,使之产生一定量的ＮＯ,ＮＯ在介导双歧杆菌的多种生理功能方面起重要作用     

双歧杆菌的免疫调节作用研究现状与展望

自1899年法国巴斯德研究院的TISSIER发现双歧杆菌以来,人们对双歧杆菌进行了广泛的研究,各方面的研究结果证实：双歧杆菌是人体中很重要的益生菌,是健康人肠道内定植且数量占优势的一种细菌,具有免疫调节、抗肿瘤、抗感染、抗衰老、降血脂、营养保健等一系列特殊生理功能。但双歧杆菌的免疫调节作用一直以来都是研究的热点,双歧杆菌通过竞争作用机制粘附到肠黏膜上皮,其菌体成分或其分泌至菌体外的可溶性物质如生物素、抗菌物质和菌体外多糖（EPS）等能通过M细胞进入集合淋巴结,激活T细胞和B细胞,从而调节和增强机体的免疫能力。近几年来各国学者在此领域取得了丰硕的成果,现将该方面的研究现状综述如下。     

双歧杆菌的遗传学分类方法研究进展

双歧杆菌(Bifidobacterium)是人和动物肠道内最主要的生理性细菌之一,在微生态学上属于原籍菌群,它与其它生理性细菌成员构成一个微生物群落,并与宿主构成一个微生态系统。因为双歧杆菌具有维持微生态平衡、生物拮抗、免疫调节、营养等多方面的生理功能,所以双歧杆菌被开发成微生态制剂广泛应用于医疗、保健、食品等并已成为微生态制剂的核心。目前双歧杆菌可分为32个种型[1]。其中已用于微生态制剂的生产菌种有两歧双歧杆菌、长双歧杆菌、短双歧杆菌、婴儿双歧杆菌和青春型双歧杆菌等。自从1899年Tissier发现双歧杆菌至今,双歧杆菌的分类…     

Insights into the taxonomy, genetics and physiology of bifidobacteria

Despite the generally accepted importance of bifidobacteria as probiotic components of the human intestinal microflora and their use in health promoting foods, there is only limited information about their phylogenetic position, physiology and underlying genetics. In the last few years numerous molecular approaches have emerged for the identification and characterization of bifidobacterial strains. Their use, in conjunction with traditional culturing methods, has led to a polyphasic taxonomy which has significantly enhanced our knowledge of the role played by these bacteria in the human intestinal ecosystem. The recent adaptation of culture-independent molecular tools to the fingerprinting of intestinal and food communities offers an exciting opportunity for revealing a more detailed picture of the true complexity of these environments. Furthermore, the availability of bifidobacterial genome sequences has advanced knowledge on the genetics of bifidobacteria and the effects of their metabolic activities on the intestinal ecosystem. The release of a complete Bifidobacterium longum genome sequence and the recent initiative to sequence additional strains are expected to open up a new era of comparative genomics in bifidobacterial biology. Moreover, the use of genomotyping allows a global comparative analysis of gene content between different bifidobacterial isolates of a given species without the necessity of sequencing many strains. Genomotyping provides useful information about the degree of relatedness among various strains of Bifidobacterium species and consequently can be used in a polyphasic identification approach. This review will deal mainly with the molecular tools described for bifidobacterial identification and the first insights into the underlying genetics involved in bifidobacterial physiology as well as genome variability.     

一株双歧杆菌质粒聚合酶基因的PCR扩增和鉴定

目的PCR扩增人双歧杆菌天然质粒的聚合酶基因。方法用改良型MRS双歧杆菌选择培养基,从人新鲜粪便分离长双歧杆菌,PCR扩增长双歧杆菌质粒聚合酶(Bifidobacterium plasmid polymerase,BPP)基因,对BPP基因检测阳性的PCR产物通过序列分析,进行鉴定。结果人长双歧杆菌天然质粒的聚合酶基因PCR扩增后,经1.0%琼脂糖凝胶电泳,测得BPP基因的相对分子质量约为1.9 kb。通过BLAST序列比对分析与GenBank中相应基因同源性为96%。结论成功克隆了1株双歧杆菌天然质粒的聚合酶基因,为构建与双歧杆菌宿主质粒相适应的载体奠定了基础。     

Marine molecular biology: an emerging field of biological sciences

An appreciation of the potential applications of molecular biology is of growing importance in many areas of life sciences, including marine biology. During the past two decades, the development of sophisticated molecular technologies and instruments for biomedical research has resulted in significant advances in the biological sciences. However, the value of molecular techniques for addressing problems in marine biology has only recently begun to be cherished. It has been proven that the exploitation of molecular biological techniques will allow difficult research questions about marine organisms and ocean processes to be addressed. Marine molecular biology is a discipline, which strives to define and solve the problems regarding the sustainable exploration of marine life for human health and welfare, through the cooperation between scientists working in marine biology, molecular biology, microbiology and chemistry disciplines. Several success stories of the applications of molecular techniques in the field of marine biology are guiding further research in this area. In this review different molecular techniques are discussed, which have application in marine microbiology, marine invertebrate biology, marine ecology, marine natural products, material sciences, fisheries, conservation and bio-invasion etc. In summary, if marine biologists and molecular biologists continue to work towards strong partnership during the next decade and recognize intellectual and technological advantages and benefits of such partnership, an exciting new frontier of marine molecular biology will emerge in the future.     

Quantitative assessment of faecal bifidobacterial populations by real-time PCR using lanthanide probes

AIM: To develop real-time quantitative PCR methods, based on the use of probes labelled with a stable fluorescent lanthanide chelate, for the quantification of different human faecal bifidobacterial populations. METHODS AND RESULTS: The designed quantitative PCR assays were found to be specific for the corresponding Bifidobacterium species or groups (Bifidobacterium longum group, Bifidobacterium catenulatum group, Bifidobacterium adolescentis, Bifidobacterium breve, Bifidobacterium angulatum, Bifidobacterium bifidum and Bifidobacterium dentium). The detection limits of the methodologies used ranged between 2 x 10(5) and 9 x 10(3) cells g(-1) of faeces. The applicability of the developed assays was tested by analysing 20 human faecal samples. Bif. longum group was found to be the qualitatively and quantitatively predominant bifidobacterial group. CONCLUSIONS: The real-time PCR procedures developed here are specific, accurate, rapid and easy methods for the quantification of Bifidobacterium groups or species in human faecal samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The developed procedures will facilitate rapid and objective counting of large numbers of samples increasing our knowledge on the role of gut bifidobacterial microbiota in health and disease. This will contribute to the efficient use of intestinal bacterial assays in research, food and pharmaceutical development as well as in the assessment of dietary management of diseases.     

Binding of human plasminogen to Bifidobacterium

Bifidobacteria constitute up to 3% of the total microbiota and represent one of the most important health-promoting bacterial groups of the human intestinal microflora. The presence of Bifidobacterium in the human gastrointestinal tract has been directly related to several health-promoting activities; however, to date, no information about the specific mechanisms of interaction with the host is available. In order to provide some insight into the molecular mechanisms involved in the interaction with the host, we investigated whether Bifidobacterium was able to capture human plasminogen on the cell surface. By using flow cytometry, we demonstrated a dose-dependent human plasminogen-binding activity for four strains belonging to three bifidobacterial species: Bifidobacterium lactis, B. bifidum, and B. longum. The binding of human plasminogen to Bifidobacterium was dependent on lysine residues of surface protein receptors. By using a proteomic approach, we identified five putative plasminogen-binding proteins in the cell wall fraction of the model strain B. lactis BI07. The data suggest that plasminogen binding to B. lactis is due to the concerted action of a number of proteins located on the bacterial cell surface, some of which are highly conserved cytoplasmic proteins which have other essential cellular functions. Our findings represent a step forward in understanding the mechanisms involved in the Bifidobacterium-host interaction.     

保护生物学一新分支学科——保护遗传学

研究人类对生物多样性的影响以及防止物种灭绝是保护生物学的两个主要目的。随着环境日益恶化、分子遗传学的迅速发展以及保护生物学和分子遗传学的不为民相互渗透,和产生了一全新的分支学科－－保护遗传学。保护遗传学是保护生物学研究中的一个核心部分,主要研究濒危物种的遗传多样性和保护物种的进化潜力。目前保护遗传学已成为国际上的一个研究热点,但在我国才刚刚起步,为此,本文就保护,遗传学的产生和发展及其研究内容和意义作一简要介绍,以推动我国在该方面的研究。     

In vitro utilization of amylopectin and high-amylose maize (Amylomaize) starch granules by human colonic bacteria.

It has been well established that a certain amount of ingested starch can escape digestion in the human small intestine and consequently enters the large intestine, where it may serve as a carbon source for bacterial fermentation. Thirty-eight types of human colonic bacteria were screened for their capacity to utilize soluble starch, gelatinized amylopectin maize starch, and high-amylose maize starch granules by measuring the clear zones on starch agar plates. The six cultures which produced clear zones on amylopectin maize starch- containing plates were selected for further studies for utilization of amylopectin maize starch and high-amylose maize starch granules A (amylose; Sigma) and B (Culture Pro 958N). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to detect bacterial starch-degrading enzymes. It was demonstrated that Bifidobacterium spp., Bacteroides spp., Fusobacterium spp., and strains of Eubacterium, Clostridium, Streptococcus, and Propionibacterium could hydrolyze the gelatinized amylopectin maize starch, while only Bifidobacterium spp. and Clostridium butyricum could efficiently utilize high-amylose maize starch granules. In fact, C. butyricum and Bifidobacterium spp. had higher specific growth rates in the autoclaved medium containing high-amylose maize starch granules and hydrolyzed 80 and 40% of the amylose, respectively. Starch-degrading enzymes were cell bound on Bifidobacterium and Bacteroides cells and were extracellular for C. butyricum. Active staining for starch-degrading enzymes on SDS-PAGE gels showed that the Bifidobacterium cells produced several starch-degrading enzymes with high relative molecular (M(r)) weights (>160,000), medium-sized relative molecular weights (>66,000), and low relative molecular weights (<66,000). It was concluded that Bifidobacterium spp. and C. butyricum degraded and utilized granules of amylomaize starch.     

Complete genome sequence of Bifidobacterium bifidum S17

Here, we report on the first completely annotated genome sequence of a Bifidobacterium bifidum strain. B. bifidum S17, isolated from feces of a breast-fed infant, was shown to strongly adhere to intestinal epithelial cells and has potent anti-inflammatory activity in vitro and in vivo. The genome sequence will provide new insights into the biology of this potential probiotic organism and allow for the characterization of the molecular mechanisms underlying its beneficial properties.     

Application of the methods of molecular systematics to classification and identification of bacteria of the genus Bifidobacterium

The methods of molecular systematics currently used in the classification and identification of bifidobacteria are reviewed. The sequencing of the 16S rRNA gene and some other genes considered to be phylogenetic markers is a universal and effective approach to taxonomic characterization of members of the genus Bifidobacterium and to reliable identification of new isolates. Various techniques of obtaining DNA fingerprints (PFGE, RAPD, rep-PCR) are widely used for solving particular problems in identifying bifidobacteria. Bacteria of the genus Bifidobacterium are important organisms in biotechnology and medicine. The research into molecular systematics of bifidobacteria provides a basis not only for the solution of taxonomic problems, but also for monitoring of individual species in the environment and for more detailed study of the genetics and ecology of this group of microorganisms.