食源性致病菌高通量检测方法及应用

食源性致病菌的体外培养一直是病原体诊断的金标准,但按照目前的培养技术仅有1％的细菌可以培养.目前用于病原微生物鉴定的高通量检测技术主要有:多重PCR技术、实时荧光定量PCR技术、核酸等温扩增技术、焦磷酸测序技术和芯片技术等,本文介绍了这些高通量检测技术及其在食品病原微生物检测方面的应用情况.     

交叉缩放椭圆管中微生物污垢特性

【目的】为研究微生物污垢在换热表面的沉积规律, 实验研究了交叉缩放椭圆管与光管的微生物污垢的沉积特性。【方法】实验以松花江水中分离纯化出的铁细菌为菌种, 利用污垢动态模拟试验系统, 采用对比的试验方法研究了铁细菌在工业运行环境下流速及水质参数的变化对表面污垢行程的影响。【结果】由于交叉缩放椭圆管的强化湍流作用, 使交叉缩放椭圆管内污垢沉积量小于光管; 水的流速越大, 换热管内铁细菌平均沉积量越小; 交叉缩放椭圆管内工质pH、电导率随微生物污垢的沉积先升高、然后趋于平缓; 而二价铁离子含量、COD值、溶解氧含量随微生物污垢的沉积逐渐下降。【结论】交叉缩放椭圆管的抗垢性能优于光管; 微生物污垢形成对冷却水水质参数的变化影响明显。     

土壤宏基因组学技术及其应用

传统的基于培养的研究方法只能反映土壤中少数(0.1%～10 %)微生物的信息,而大部分微生物目前还不能培养,因而这部分微生物资源尚难以被有效地开发利用.宏基因组学是分子生物学技术应用于环境微生物生态学研究而形成的一个新概念,主要技术包括土壤DNA的提取、文库的构建和目标基因克隆的筛选.它可为揭示微生物生态功能及其分子基础提供更全面的遗传信息,并已在微生物新功能基因筛选、活性物质开发和微生物多样性研究等方面取得了显著成果.本文对土壤宏基因组学技术的方法和应用作了详细介绍.     

多重PCR检测技术在食品微生物检测中的应用

现代食品行业,有很多有害的微生物严重危害食品的品质和人们的健康,甚至会引起一些严重的疾病。食品安全是对食品按其原定用途进行制作和(或)食用时不会使消费者受到伤害的一种担保。食品安全急需一些快速、敏感、特异的检测方法,以及时发现致病菌,控制污染及其可能对人体健康产生的危害。多重PCR检测技术具有快速、简便微量等优点,克服了传统检测方法操作繁琐,检测时间较长等缺点,目前正在被应用于微生物致病菌,转基因产品以及肉类品种的鉴定上,具有广阔的发展前景。本文主要是介绍了多重PCR检测技术在食品微生物检测中的原理和应用,以期望在食品微生物检测方面做出贡献。     

rRNA技术及其在分子微生物生态上的应用

传统的基于微生物培养与纯种分离的技术所具有的局限性,以及分子生物学及其有关技术的长足进展,使微生物生态学的研究进入了分子的阶段.其中rRNA技术的建立、发展及其成功应用,为分子微生物生态和微生物系统分类学的研究掀开了崭新的一页.对rRNA分子技术的研究进展、以之为基础的主要方法及其在环境微生物研究中的应用,以及应用过程中所存在的一些潜在问题及其解决办法等作了详细综述.     

PCR-DGGE技术及其在植物微生态研究中的应用

植物中微生物种类较为丰富,在植物微生态系统中发挥重要作用.变性梯度凝胶电泳(denaturing gradient gel electrophoresis,DGGE)技术作为研究微生物物种多样性和种群动态变化的分子检测工具之一,广泛应用于植物微生物群落多样性和群落动态变化研究中.概述了DGGE技术的原理,及其在植物微生物生态学中的应用以及在该领域研究中导致DGGE偏差的因素和相应解决方法,对DGGE检测结果的分析提供参考,为进一步研究植物微生物相互作用提供帮助.     

基于高通量测序技术的微生物检测数据分析方法

高通量测序技术的发展正在逐渐改变诸多生物学领域的研究方法.为应对突发疫情以及新发未知微生物威胁的需求,微生物鉴定技术逐渐从传统的物理化学方法及核酸杂交等分子水平方法进一步走向利用无需培养的测序数据进行快速分析检测.随之而来的是对高通量数据分析在精度及速度的要求.基于高通量测序数据的微生物检测数据分析方法在近些年得到了快速的发展.本文分析了目前基于高通量测序数据的微生物检测数据分析方法,对其数据分析的处理流程和计算方法进行了研究,比较了各个微生物检测数据分析方法的特点及适用场景.最后结合本实验室工作总结微生物检测数据分析方法在实际应用中可能遇到的问题,希望对该应用领域的研究有一定的参考意义.     

常见食源性致病菌代谢组学研究进展

食源性致病菌是一类以食品为传播媒介,可引起食物中毒的致病性微生物,是目前食源性疾病的主要诱因。食源性致病菌代谢组学通过研究致病菌代谢小分子物质产生的规律性和特征性,寻找新的检测靶标和建立基于代谢组学方法的食源性致病菌鉴别技术。随着目前代谢组学研究技术逐渐成熟和微生物挥发性代谢产物数据库的建立,食源性致病菌挥发性代谢产物分析已被建议作为临床和食品中致病菌鉴别的替代方法。本文综述了目前常见食源性致病菌代谢组学主要研究技术及其在临床和食品检测中的研究进展,以期为进一步建立食源性致病菌代谢产物数据库和研发基于代谢组学方法的食源性致病菌检测技术提供参考。     

寡核苷酸芯片在微生物检测中的应用

近几年来发展起来的基因组研究技术———基因芯片技术为微生物检测提供了一种强有力的手段。目前国内外已广泛地开展了利用寡核苷酸芯片对多种微生物 (主要是病毒和细菌 ,少量有真菌 )进行相关检测的研究 ,并在对微生物病原体检测、种类鉴定、功能基因检测、基因分型、突变检测、基因组监测等方面获得了成功。由于寡核苷酸探针具有可根据研究需要任意设计、特异性高等特点 ,寡核苷酸芯片在微生物检测中有着巨大的应用价值 ,具有广阔的应用前景。     

微生物组学的技术和方法及其应用

微生物组是指一个特定环境或生态系统中全部微生物及其遗传信息的集合, 其蕴藏着极为丰富的微生物资源。全面系统地解析微生物组的结构和功能, 将为解决人类面临的能源、生态环境、工农业生产和人体健康等重大问题带来新思路。然而, 微生物组学研究在很大程度上取决于其技术与方法的发展。在高通量测序技术出现以前, 微生物研究主要基于分离培养和指纹图谱等技术, 然而, 由于这些技术存在的缺陷, 人们对于微生物的认识十分有限。自21世纪初以来, 尽管高通量测序和质谱技术的革命性突破极大地促进了人们对于微生物的认识, 微生物组学技术在微生物组研究中的应用仍面临着诸多挑战。此外, 目前微生物组的结构和多样性等描述性研究已臻成熟, 微生物组学研究正处于从数量到质量、从结构到功能的关键转变时期。因此, 该文首先介绍了微生物组学的基本概念及其发展简史, 其次简述了微生物组学研究的相关技术和方法及其发展历程, 并进一步阐述了微生物组学的技术和方法在生态学研究中的应用及存在的主要问题, 最后从技术、理论和应用层面阐述了未来微生物组学技术和方法发展的前沿方向, 并提出了今后微生物组学研究的优先发展领域。     

生物被膜的形成及其电化学阻抗检测

生物被膜是细菌及其自身分泌的胞外聚合物组成的微生物群落,其形成是受多种机制共同调控的多阶段动态过程,具有较强的耐药性且难以清除,给医疗、食品等行业带来了巨大的威胁。近年来,生物被膜的相关研究领域备受关注,尤其是针对生物被膜的有效检测技术。本文在简要介绍生物被膜的特点、形成过程及群感效应对生物被膜的调控作用基础之上,总结了生物被膜常用的检测方法,重点针对电化学阻抗技术在生物被膜检测中的应用进行调研和讨论,并对基于微流控芯片的生物被膜电化学阻抗原位检测进行了综述和展望。     

淡水入侵生物沼蛤的污损机制与防污措施研究进展

沼蛤是一种典型的淡水入侵贝类,能够利用其分泌的足丝牢固黏附在多种水下基质表面,引起严重的生物污损问题。沼蛤污损不但影响水生态系统健康,也给水利工程、交通运输、水产养殖等行业带来经济损失,已成为全球水生态系统安全和国民经济重要行业的潜在威胁,相关防污工作亟待开展。欲从根本上解决沼蛤污损问题,一方面需要加强对其基础生物学特性和污损机制的深入解析,另一方面也需要在此基础上研发更加经济、高效、环境友好的防污措施。本文综述了近年来国内外关于沼蛤污损生物学特性、污损机制和防污措施方面的研究进展,尤其是对沼蛤生物污损发生的主要机制如足探测识别、足丝黏附和环境影响等方面进行了总结,也从物理、化学、生物和防污材料等角度阐述了现有的沼蛤污损控制措施并对未来发展方向进行了展望,以期更加深入地理解沼蛤生物污损现象,为揭示其作用机制、制定科学有效的防污措施、维护水生态系统安全提供数据支撑,综述内容对于水下仿生材料研发也具有重要的参考价值。     

Biodeterioration of crude oil and oil derived products: a review

Biodeterioration of crude oil and oil fuels is a serious economic and an environmental problem all over the world. It is impossible to prevent penetration of microorganisms in oil and fuels both stored in tanks or in oilfields after drilling. Both aerobic and anaerobic microorganisms tend to colonise oil pipelines and oil and fuel storage installations. Complex microbial communities consisting of both hydrocarbon oxidizing microorganisms and bacteria using the metabolites of the former form an ecological niche where they thrive. The accumulation of water at the bottom of storage tanks and in oil pipelines is a primary prerequisite for development of microorganisms in fuels and oil and their subsequent biological fouling. Ability of microorganisms to grow both in a water phase and on inter-phase of water/hydrocarbon as well as the generation of products of their metabolism worsen the physical and chemical properties of oils and fuels. This activity also increases the amount of suspended solids, leads to the formation of slimes and creates a variety of operational problems. Nowadays various test-systems are utilized for microbial monitoring in crude oils and fuels; thus allowing an express determination of both the species and the quantities of microorganisms present. To suppress microbial growth in oils and fuels, both physico-mechanical and chemical methods are applied. Among chemical methods, the preference is given to substances such as biocides, additives, the anti-freezing agents etc that do not deteriorate the quality of oil and fuels and are environmentally friendly. This review is devoted to the analysis of the present knowledge in the field of microbial fouling of crude oils and oil products. The methods utilized for monitoring of microbial contamination and prevention of their undesirable activities are also evaluated. The special focus is given to Russian scientific literature devoted to crude oil and oil products biodeterioration.     

Emerging waterborne pathogens: can we kill them all?

The rapid emergence of Cryptosporidium parvum and Escherichia coli 0157:H7 have created a threat to the drinking water industry and there is a growing need to develop a strategy for recognizing potential emerging waterborne pathogens. Globalization of trade, changing population demographics and changes in treatment technology have been driving factors in the emergence of these new pathogens. An understanding of disinfectant action and microbial resistance to treatment processes is needed to better identify those pathogens likely to be of greatest concern. Recent research on microbial resistance to treatment and disinfection demonstrates that the microbial surface structure and composition and the nature of the genome are key to determining the potential for waterborne transmission of emerging pathogens.     

Microbial mats associated with bryozoans (Coorong Lagoon, South Australia)

Summary Bryostromatolites are laminated carbonate rocks composed of bryozoan zoarial laminae. The laminated texture is frequently caused by patterns of bryozoan self overgrowth as a regular defensive tactic against microbial fouling. In the Coorong Lagoon (South Australia), another type of bryostromatolite is present where the laminated growth of the weakly calcifying bryozoan speciesConopeum aciculata is postmortally stabilized by cyanobacterial mats at the surface, and fungal mats settling in the zooecial cavities. A tough extracellular slime network produced by benthic cyanobacteria is a trap for sediment particles, provides a method of adhesion to the bryozoan substrate, and produces a biological lamination by the vertical stratification of dead bryozoan skeletons. These slimes are also important for the preservation of cell structures and for their fossilization. Seasonal fluctuations in salinity and water level are the most important regional control factors, causing a phase displacement in the growth optima of microbial mats and bryozoans, thereby resulting in a rigid bryostromatolitic fabric.     

Current and future trends for biofilm reactors for fermentation processes

Biofilms in the environment can both cause detrimental and beneficial effects. However, their use in bioreactors provides many advantages including lesser tendencies to develop membrane fouling and lower required capital costs, their higher biomass density and operation stability, contribution to resistance of microorganisms, etc. Biofilm formation occurs naturally by the attachment of microbial cells to the support without use of any chemicals agent in biofilm reactors. Biofilm reactors have been studied and commercially used for waste water treatment and bench and pilot-scale production of value-added products in the past decades. It is important to understand the fundamentals of biofilm formation, physical and chemical properties of a biofilm matrix to run the biofilm reactor at optimum conditions. This review includes the principles of biofilm formation; properties of a biofilm matrix and their roles in the biofilm formation; factors that improve the biofilm formation, such as support materials; advantages and disadvantages of biofilm reactors; and industrial applications of biofilm reactors.     

微生物固定化及其在环境污染治理中的应用研究进展

微生物固定化技术广泛应用于食品、轻化以及环保领域,其具有微生物密度高、生物活性好、环境适应性强、可反复利用等优点。本文对微生物固定化技术进行了概述,并通过典型案例重点阐释了其在水、土和大气等环境污染治理领域的应用进展。在水环境中,固定化载体可为不同类型微生物提供生存微环境和各自所需的生态位,提高了系统负荷和处理效能;在土壤环境中,其重要作用在于提高土壤中污染物的生物有效性,从而提升微生物修复效果;空气污染治理领域则更注重载体的机械强度及气液传质能力的提高。本文比较总结了微生物固定化技术在不同环境治理领域中的应用特点和优势,以期为今后的环境污染治理提供一定的参考。     

膜前助滤预处理对高藻水微滤膜污染的影响研究

研究采用添加硅藻土、植物棉、活性炭等3种不同预处理手段来过滤铜绿微囊藻,并考察未预处理及预处理后的藻液过滤过程中的过滤特性、有机物分布及膜污染特性。结果表明, 3种预处理手段对过滤通量均有所提高并减缓膜污染。其中,硅藻土预处理提高平均过滤通量达915%,明显优于其他助滤手段。活性炭预处理能够有效吸附芳香族蛋白质类荧光污染物,显著降低污染膜的不可逆化学污染阻力。通过OCT及SEM分析可知未预处理的高藻水直接过滤造成的膜污染最严重,饼层结构的粗糙度最低并且厚度也最小,而硅藻土通过优化饼层结构以达到缓解膜污染的效果。最后基于XDLVO理论结果也进一步证实硅藻土预处理手段对改善膜污染效果最好。研究结果对未来蓝藻水华膜处理技术的预处理手段研发具有指导意义。     

Film forming microbial biopolymers for commercial applications—A review

Abstract

Microorganisms synthesize intracellular, structural and extracellular polymers also referred to as biopolymers for their function and survival. These biopolymers play specific roles as energy reserve materials, protective agents, aid in cell functioning, the establishment of symbiosis, osmotic adaptation and support the microbial genera to function, adapt, multiply and survive efficiently under changing environmental conditions. Viscosifying, gelling and film forming properties of these have been exploited for specific significant applications in food and allied industries. Intensive research activities and recent achievements in relevant and important research fields of global interest regarding film forming microbial biopolymers is the subject of this review. Microbial polymers such as pullulan, kefiran, bacterial cellulose (BC), gellan and levan are placed under the category of exopolysaccharides (EPS) and have several other functional properties including film formation, which can be used for various applications in food and allied industries. In addition to EPS, innumerable bacterial genera are found to synthesis carbon energy reserves in their cells known as polyhydroxyalkanoates (PHAs), microbial polyesters, which can be extruded into films with excellent moisture and oxygen barrier properties. Blow moldable biopolymers like PHA along with polylactic acid (PLA) synthesized chemically in vitro using lactic acid (LA), which is produced by LA bacteria through fermentation, are projected as biodegradable polymers of the future for packaging applications. Designing and creating of new property based on requirements through controlled synthesis can lead to improvement in properties of existing polysaccharides and create novel biopolymers of great commercial interest and value for wider applications. Incorporation of antimicrobials such as bacteriocins or silver and copper nanoparticles can enhance the functionality of polymer films especially in food packaging applications either in the form of coatings or wrappings. Use of EPS in combinations to obtain desired properties can be evaluated to increase the application range. Controlled release of active compounds, bioactive protection and resistance to water can be investigated while developing new technologies to improve the film properties of active packaging and coatings. An holistic approach may be adopted in developing an economical and biodegradable packaging material with acceptable properties. An interdisciplinary approach with new innovations can lead to the development of new composites of these biopolymers to enhance the application range. This current review focuses on linking and consolidation of recent research activities on the production and applications of film forming microbial polymers like EPS, PHA and PLA for commercial applications.     

An automated system for biocide testing on biofilms*

The paper presents and discusses a novel on-line real-time non-destructive continuous-flow system for biocide testing on industrial biofilms. This laboratory system is capable of monitoring changes in growth, accumulation and respiratory activity of biofilms in response to biocidal treatment. The system incorporates a fouling monitor for continuous measuring of the rate of biofilm accumulation (heat transfer resistance), a sensor for monitoring of microbial activity (oxygen meter for monitoring the rate of biofilm respiratory activity), and subsystems necessary for microbial life support and control of operation parameters. Examples of system operation and testing of oxidizing and non-oxidizing biocides are presented. Received 25 May 1997/ Accepted in revised form 25 November 1997