PCR-DGGE法评价连续培养模型中肠道菌群的多样性

目的建立人体肠道菌群连续培养模型,验证连续培养模型培养肠道菌群的可行性和稳定性。方法建立连续培养系统,把正常人粪便接种于发酵罐中培养,通过活菌计数和PCR—DGGE法分析连续培养系统中菌群的多样性变化。结果连续培养系统中菌群数量由接种前的10^10～10^11CFU／ml降至10^8-10^9CFU／ml并最终达到稳态;PCR—DGGE法分析结果表明,菌群的多样性指数稳定,各条带均匀度趋于一致。结论连续培养模型能较好模拟人体肠道微生态环境,再现了肠道菌群组成的多样性,可作为肠道菌群培养及菌群相关性研究的离体模型。     

防御素调节腹盆腔放疗肠道微生态失调的研究进展

防御素作为内源性的抑菌/杀菌剂对胃肠道菌群平衡有重要作用,还可用来改善肠内菌群生态失调。放疗在杀伤癌细胞同时对正常细胞有较大影响,影响肠道屏障和肠内菌群平衡。而防御素有协同抗微生物活性和免疫应答作用,可改善腹盆腔放疗后胃肠道微生态失调。本研究对防御素、肠道微生态、腹盆腔放疗后防御素与微生态失调以及防御素对腹盆腔治疗的影响等做一综述。     

双歧杆菌耐药性与质粒

随着微生态学理论与实践的不断发展,人们对维持正常菌群的生态平衡的重要性的认识越来越深刻［１］。根据微生态学的有关理论,多种活菌制剂已经被开发出来,在临床被用于恢复人体的正常菌群,用来治疗各种因素导致的肠道菌群失调［２］。现就与双歧杆菌活菌制剂研制和临...     

肠道菌群与疾病发生及中草药调节和治疗作用的研究概述

肠道正常菌群及微生态稳定对人体极具重要性,中草药对肠道菌群具有调节作用.本文综述了人体的肠道正常菌群与疾病产生和发展的关系,结合中草药对肠道菌群调节作用的研究,探讨中药调节肠道菌群与其发挥疾病防治效果之间的相关性,以期为中草药的临床应用及药理学研究提供一定的参考依据.     

肠道菌群:运动健康促进的新靶点

肠道菌群与人体通过广泛信息交流形成互惠共生关系。肠道菌群结构稳定性、菌种多样性和微生态平衡性使其成为人体更易接触和调控的"生理中心",深刻影响人体健康。适宜运动可通过优化肠道菌群,促进宿主肠道微生态健康。以肠道菌群为靶点的运动健康促进研究,为运动与人体健康和疾病研究呈现出新领域。基于宏基因组学、宏转录组学等微生态研究技术,揭示与人体疾病相关的肠道菌群失调,鉴定出疾病相关的特定菌群种类及功能,使得以肠道菌群为靶点的运动精准干预人体健康成为可能。     

纪念康白先生微生态学术座谈会在大连召开

正4月24日我刊在大连市君悦酒店举行了纪念康白先生微生态学术座谈会。康白教授是我国微生态学的奠基人与推动者,著名的微生态学家和微生物学家。从上世纪50年代起,康白教授就从事正常菌群的研究工作,他提出了正常菌群、菌群失调、菌交替症等微生态学概念和理论,建立了正常菌群的研究方法,成功探索了菌群调整疗法,发明了"促菌生" "回春生""定君生"等国家微生态新药,奠定了我国微生态学研究和应用的基础。     

欧洲的微生态学研究

欧洲是微生态学这门综合性边缘学科的主要发源地。早在1861年,巴斯德就发现了厌氧菌的生理学功能,并由此创造了简单的厌氧培养方法;随后,在1885年,他首次提出了无菌动物的概念及研究正常菌群与宿主关系的重要意义,并指出了正常菌群对于动物宿主生命的重要性。现代的无菌动物技术诞生于1945年,连续性厌氧培养技术也出现于五十年代,欧洲学者对于这二项技术的完善也做出了自己的贡献。目前,这二项技术已成为微生态学研究必不可少的工具。     

女性阴道微生态状况与母婴健康

女性阴道是自然开放的腔道,其内寄居着大量的微生物,其中乳杆菌占优势。正常阴道内的微生物对于维持女性生殖系统健康具有重要作用,而多种因素能够影响妇女正常的阴道微生态环境,包括妊娠。女性阴道微生态状况不仅会影响自身健康,同时能够影响子代的健康。正常的肠道菌群参与机体的营养、免疫、代谢、神经内分泌等多种生理功能,而婴儿期是人肠道菌群建立的关键时期,其中分娩方式对婴儿菌群的定植和发展具有重要的影响。阴道菌群失衡不但可导致妇女感染性疾病的发生,还与妊娠结局及婴儿菌群的建立密切相关,改善女性阴道微生态状况对提高母婴健康具有重要意义。     

结直肠癌患者肠道黏膜菌群多样性变化研究

目的应用PCR-DGGE技术对结直肠癌患者肠道黏膜局部菌群多样性进行研究,为结直肠病变的防治提供微生态调节思路。方法收集正常对照组、结直肠息肉组及结直肠癌组患者各30例,采集结直肠黏膜局部肛拭子,提取细菌基因组DNA,采用PCR-DGGE对肠道黏膜局部菌群进行指纹图谱分析。结果正常对照组、结直肠息肉组和结直肠癌组患者PCR-DGGE指纹图谱分析显示3组肠道黏膜局部菌群多样性发生了显著的变化,3组肠道黏膜局部菌群发生了显著的菌群变迁。结论 PCR-DGGE分析结直肠癌患者肠道黏膜局部菌群多样性变化对监测肠道局部微生态变化在结直肠癌的发生过程中的作用具有重要价值。     

鸡盲肠菌群的厌氧连续培养及培养物的生理生化特性

目的 对鸡盲肠菌群的厌氧连续培养方法及培养物的生理生化的特性进行初步研究。方法用鸡盲肠内容物接种连续培养装置,进行厌氧连续培养,稀释率为０．０４ｈ＾－４,运转７－１０ｈ后达到稳定状态。在稳定状态时,对培养系统中的菌群结构、ｐＨ、ＯＤ值以及挥发性脂肪酸（ＶＦＡ）进行了分析。结果 当该培养系统过以稳定状态时,培养物的ｐＨ、ＯＤ值,以及ＶＦＡ的产量都达到了一个相对稳定的水平。结论 有机酸中的丁酸、乙酸、     

In situ morphology of nitrifying-like bacteria in aquaculture systems.

The in situ microbiota from several aquaculture facilities with active nitrification was examined by transmission electron microscopy of thin sections for the presence of bacteria that contained intracytoplasmic membranes characteristic of the nitrifying bacteria. Colonies of bacteria with the cellular morphology of a species of Nitrosomonas were found to be present in both the culture water and in the biological filter slime of a freshwater chinook salmon (Oncorhynchus tshawytscha) culture system. bacteria in the water possessed the normal nitrosomonas type of ultrastructure, whereas similar bacteria in the slime had an aberrant morphology due to multiple invaginations of the cell wall and cyto-membranes and a significantly greater number of ribosomes. These nitrosomonas-like bacteria lysed during enrichment in commonly used media. Bacteria with the morphology of species of Nitrosomonas and Nitrosococcus were also observed in colonies in the surface slimes of marine culture systems for striped bass (Morone saxatilis) and quahaug (Mercenaria mercenaria).     

Feeding and Mating Reactivity in Paramecium multimicronucleatum

SYNOPSIS. Paramecium multimicronucleatum produced abnormal (L- and Δ-shaped) cells when cultivated in the presence of 3 mM adenine. These abnormal cells were unable to form food vacuoles in the presence of bacteria in the culture. In bacteria-rich culture, mating reactivity was not expressed in normal Paramecium ; however, it was expressed in the adenine-treated abnormal cells even in the presence of excess bacteria. The expression of mating reactivity in Paramecium was not affected by ingestion of polystyrene latex particles. These results show that the inhibition of mating reactivity in bacterized culture medium is caused by absorption of nutrients from bacteria digested in food vacuoles.     

Effect of long-term lead exposure on the seawater and sediment bacteria from heterogeneous continuous flow cultures

Lead-influenced changes of the composition of seawater and sediment bacteria were studied in two flow cultures run with lead-contaminated artificial seawater (1 mg Pb²⁺1^–1) and one control culture. During the experiment viable counts of physiological groups of bacteria from the control culture were not significantly different from that of the lead-contaminated cultures. Lead tolerance of seawater and sediment bacteria strains was investigated. Comparisons of growth yields showed that lead tolerance of seawater and sediment bacteria was lost again if the bacteria were cultivated in a medium without lead. Lead tolerance could not be demonstrated for the sediment bacteria of one lead-contaminated culture. Heterotrophic uptake measurements with radioactive glucose indicated that seawater bacteria from the lead-contaminated cultures became adapted to lead pollution. The sediment bacteria, however, did not reveal lead tolerance by this method. Fluctuations in lead content of the sediment as well as of the overlying seawater gave indications of adsorption-desorption processes between seawater and sediment. Lead was not homogeneously distributed at the sediment surface.     

Determination of diauxic lag in continuous culture

A procedure was developed to characterize diauxic lag of bacteria switching between electron acceptors in continuous culture. In this procedure, a virtual batch growth curve is developed by integrating the time-dependent net specific growth rates of bacteria observed under continuous flow conditions. The length of diauxic lag and the highest net specific growth rate following lag are conveniently estimated from the virtual batch curve. The procedure was found to give reproducible diauxic lag lengths and highest net specific growth rates when applied to experimental data from replicate continuous culture trials.     

Beneficial interactions between insects and gut bacteria

Insects are amongst the most successful of animals, both in terms of diversity and in colonizing all ecological niches. Recent studies have highlighted the benefi ciary roles that bacteria play in the success and establishment of insects. By adopting techniques like 16S rRNA sequencing we are now in a position to understand the diversity of bacteria present in insect guts. It has been shown that some of these bacteria, like Wolbachia and Cardinium are involved in manipulating insect populations and distorting their sex ratio. Attempts have been made to culture these bacteria in insect cell lines, as they are recalcitrant to culture under normal microbiological conditions. The diversity of bacteria associated with insects and the functional role played by them in the insect is discussed below.     

Glycogen metabolism loss: a common marker of parasitic behaviour in bacteria?

We searched 55 completely sequenced bacterial genomes for glycogen synthesis and degradation enzymes. A significant proportion of these bacteria appears to lack glycogen metabolism capability. Interestingly, these bacteria are parasitic, symbiotic or fastidious (i.e. difficult to culture outside their normal environment). It is suggested that the lack of bacterial glycogen metabolism is a trait associated with parasitic behaviour in bacteria.     

Rapid and Simple Quantification of Bacterial Cells by Using a Microfluidic Device

This study investigated a microfluidic chip-based system (on-chip flow cytometry) for quantification of bacteria both in culture and in environmental samples. Bacterial numbers determined by this technique were similar to those obtained by direct microscopic count. The time required for this on-chip flow cytometry was only 30 min per 6 samples.     

Rapid and simple quantification of bacterial cells by using a microfluidic device

This study investigated a microfluidic chip-based system (on-chip flow cytometry) for quantification of bacteria both in culture and in environmental samples. Bacterial numbers determined by this technique were similar to those obtained by direct microscopic count. The time required for this on-chip flow cytometry was only 30 min per 6 samples.     

结肠清洗后肠道微生态平衡的重建

目的观察结肠清洗对人肠道菌群的影响和结肠清洗后肠道微生态平衡再建的过程。方法10名健康男性志愿者随机平均分为2组,一组为结肠清洗后食用普通膳食,另一组为结肠清洗后,先食用航天食品,后食用普通膳食,在选定的时相点收集粪便,选择性培养基分别对肠球菌、大肠埃希菌、类杆菌、乳杆菌及双歧杆菌定量测定。结果结肠清洗后,肠道所有的微生物数量均显著减少,7d后肠道菌群恢复正常。结论结肠清洗引起肠道微生态平衡紊乱,航天食品不利于肠道微生态重建。     

Quantitative selection of denitrifying bacteria in continuous cultures and requirement for organic carbon. I. Starch

A mixed population of bacteria from bottom sludge of nitrogen wastewater reservoir was incubated in continuous culture in medium containing 1000 mg nitrate nitrogen/l and starch. Maximal efficiency of denitrification was 5 mg N/l/h. Marked changes in participation of denitrifying bacteria (16-76%) among total number of bacteria was observed, this being dependent on the ratio of starch concentration (CS) to nitrogen concentration (CN) in the medium. The optimal CS/CN ratio ensuring highest participation of denitrifying bacteria was 3.2. The amount of starch required for the denitrification of a defined quantity of nitrogen is negatively correlated (r = -0.98) with the frequency of the occurrence of denitrifying bacteria (XD) and is: CS = (5.53-0.028XD) CN. The denitrifying bacteria in continuous culture were dominated, depending on CS/CN ratio and flow rate of medium, by Alcaligenes faecalis, Paracoccus denitrificans or Pseudomonas mendocina, that is species unable to hydrolyse starch.