蛭弧菌研究进展

蛭弧菌(Bdellovibrio bacteriovorus)是一类专性捕食革兰氏阴性菌的寄生细菌,在自然界分布广泛。蛭弧菌研究集中在蛭弧菌分类和基因组分析上,并以此指导蛭弧菌噬菌机制的研究,同时在生态学研究方面也有进展。蛭弧菌的噬菌性质可能作为一种行使杀菌功能的"活抗生素"成为目前研究热点。但在应用方面还存在一些需进一步研究和解决的问题。     

鱼类致病菌的蛭弧菌研究

噬菌蛭弧菌(Bdellovibrio bacteriovors)是一类有寄生性的细菌。Stolp及Stzold(1962年)曾首次报导,我国司稚东、秦生巨等(1982年)在国内亦首次报导了这类细菌的发现。本文介绍了以鲫鱼出血病病原菌点状产气单胞菌(Aeromonas punctata)为宿主菌,经分离得到的噬菌蛭弧菌Bd3—2菌株的培养特征、细菌形态、细菌生理生化特征、感染宿主机制及在实验室条件下水体中对宿主菌净化作用等方面的研究内容。说明噬菌蛭弧菌是精养鱼塘水体中某些致病菌的自然净化的重要生物因子之一,并为利用蛭弧菌来减少或控制鱼塘细菌性病害的发生,开展生物防治新技术提供了较好的依据和途径。     

噬菌蛭弧菌生物特性研究进展

本文介绍了噬菌蛭弧菌的培养特性,温度对噬菌蛭弧菌的影响,噬菌蛭弧菌的生化特征,感染宿主的机制,在死的宿主菌中生长的特性,宿主的特异性以及噬菌蛭弧菌对致病菌的生物净化作用等生物特性的研究进展。研究认为,噬菌蛭弧菌是自然环境(水、土壤)中致病微生物的生物拮抗体,且极有可能利用它的寄生和溶解宿主菌细胞的特殊性,对环境水体的生物净化。     

鱼病蛭弧菌的微生态学初步研究

本次以鲫鱼出血性腹水病病原菌点状产气单胞菌（Ａｅｒｏｍｏｎａｓ Ｐｕｎｃｔａｔａ）为宿主菌。从自然界分离获得６株噬菌蛭弧菌菌株,它们具有噬菌蛭弧菌的生物学特性。研究表明,这６株蛭弧菌的最适培养条件为温度２５￣２８℃,ｐＨ７．２,有溶菌性,能裂解多种鱼类病原菌。其中对蛭弧菌Ｂｄｓ－４菌株在实验条件下对病原菌的自然净化作用等方面进行了研究。说明蛭弧菌是精养鱼糖水体中某些致病菌的自然净化的重要生物因素之     

噬菌蛭弧菌的分离及初步鉴定

采用双层平板法,以滤膜过滤的方法来收集噬菌蛭弧菌,以嗜水气单胞菌(Aeromonas hudrophila)、荧光假单胞菌(Pseudomonas fluorescent)和绿脓杆菌(Pseudomonas aeruginosa)为宿主菌,进行噬菌蛭弧菌的分离研究;并在此基础上,通过接触酶检测和寄生性确认对噬菌蛭弧菌(Bdellovibrio bacteriovorus)进行了初步的鉴定.结果表明未使用滤膜过滤,采用自来水琼脂双层平板法分离噬菌蛭弧菌的效果较好;并经过接触酶和寄生性检测初步鉴定此BD-SPOI菌株为噬菌蛭弧菌.     

人粪便中分离的噬菌蛭弧菌生物学特性的研究

本文研究了人粪便中分离的噬菌蛭弧菌的生物学特性,测定了它们的生长曲线,并利用微孔滤膜过滤和机械振荡的方法,研究了它们的吸附和穿入动力学,发现链霉素、庆大霉素和卡那霉素能抑制蛭弧菌的吸附;青霉素不影响蛭弧菌的吸附和穿入,但抑制蛭弧菌在宿主内的生长过程。从人粪中分出的噬菌蛭弧菌不仅能裂解大部分需氧的革兰氏阴性菌,而且在微氧条件下也能裂解厌氧菌中的二株脆弱拟杆菌。我们发现一株人粪便中分出的噬菌蛭弧菌能形成蛭弧菌囊体——它的休眠态,它对高热、紫外线照射和真空干燥的耐受力较相应的繁殖体强,看来它是蛭弧菌保持生命期限的一种方式。     

Rapid isolation of host-independent Bdellovibrio bacteriovorus

A new method of isolating host-independent Bdellovibrio bacteriovorus has been developed. Filtered suspensions of host-dependent cells are dropped in small volumes onto 0.2 μm membranes laid on rich media agar. Significant growth is observed within 1–2 days; these cells were confirmed to be B. bacteriovorus using microscopic observations and PCR.     

Microbial Endpoints: The Rationale for their Exclusion as Ecological Assessment Endpoints

The functional importance of bacteria and fungi in terrestrial systems is recognized widely. However, microbial population, community, and functional measurement endpoints change rapidly and across very short spatial scales. Measurement endpoints of microbes tend to be highly responsive to typical fluxes of temperature, moisture, oxygen, and many other noncontaminant factors. Functional redundancy across broad taxonomic groups enables wild swings in community composition without remarkable change in rates of decomposition or community respiration. Consequently, it is exceedingly difficult to relate specific microbial activities with indications of adverse and unacceptable environmental conditions. Moreover, changes in microbial processes do not necessarily result in consequences to plant and animal populations or communities, which in the end are the resources most commonly identified as those to be protected. Therefore, unless more definitive linkages are made between specific microbial effects and an adverse condition for typical assessment endpoint species, microbial endpoints will continue to have limited use in risk assessments; they will not drive the process as primary assessment endpoints.     

Ecological Strategy of Bacteria: Specific Nature of the Problem

An attempt is made to sum up the results of the many years of using the conception of ecological strategy in bacterial ecology. Taking into account the specificities of microorganisms and their natural selection and the coevolution of microorganisms within evolving microbial communities, an inference is derived that the ecological strategy of most bacteria is the sum of a number of particular canonical strategies, some of which are common to higher organisms. It is proposed to call these particular strategies ecological tactics. The author considers this review to be a basis for a discussion.     

噬菌蛭弧菌代谢产物活性成分对小鼠免疫功能的影响

目的研究噬菌蛭弧菌代谢产物活性成分对小鼠免疫功能的影响。方法将噬菌蛭弧菌代谢产物的3种有机溶剂（石油醚、三氯甲烷、乙酸乙酯）提取物和提取后的剩余液体分别腹腔注射实验小鼠,分两次注射,共注射0.5 mL,注射后连续饲养28 d,每隔7 d小鼠采血检测离体白细胞吞噬活性（phagocytic activity）、吞噬细胞杀菌活性（bactericidal activity）、超氧化物歧化酶（superoxide dismutase,SOD）活性、血清凝集抗体效价、血红蛋白值和红细胞数的变化,以研究不同提取物对小鼠免疫功能的影响。结果石油醚提取物组和三氯甲烷提取物组小鼠血清SOD活性、血清凝集抗体效价、离体白细胞吞噬活性和吞噬细胞杀菌活性增强与对照组相比差异极显著（P〈0.01）;乙酸乙酯提取物组SOD活性和血清凝集抗体效价增强与对照组相比差异极显著（P〈0.01）,离体白细胞吞噬活性和吞噬细胞杀菌活性增强与对照组相比差异显著（P〈0.05）;石油醚提取物组的血红蛋白值（12.64 g/100 mL）和红细胞数（11.32×106/mL）最高。各项指标的峰值均出现在第7天~第21天。结论噬菌蛭弧菌代谢产物3种有机溶剂提取的活性物质具有增强小鼠免疫功能的作用。     

Predation of human pathogens by the predatory bacteria Micavibrio aeruginosavorus and Bdellovibrio bacteriovorus

Aims: The focus of this study was to evaluate the potential use of the predatory bacteria Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus to control the pathogens associated with human infection. Methods and Results: By coculturing B. bacteriovorus 109J and M. aeruginosavorus ARL‐13 with selected pathogens, we have demonstrated that predatory bacteria are able to attack bacteria from the genus Acinetobacter, Aeromonas, Bordetella, Burkholderia, Citrobacter, Enterobacter, Escherichia, Klebsiella, Listonella, Morganella, Proteus, Pseudomonas, Salmonella, Serratia, Shigella, Vibrio and Yersinia. Predation was measured in single and multispecies microbial cultures as well as on monolayer and multilayer preformed biofilms. Additional experiments aimed at assessing the optimal predation characteristics of M. aeruginosavorus demonstrated that the predator is able to prey at temperatures of 25–37°C but is unable to prey under oxygen‐limiting conditions. In addition, an increase in M. aeruginosavorus ARL‐13 prey range was also observed. Conclusions: Bdellovibrio bacteriovorus and M. aeruginosavorus have an ability to prey and reduce many of the multidrug‐resistant pathogens associated with human infection. Significance and Impact of the Study: Infectious complications caused by micro‐organisms that have become resistant to drug therapy are an increasing problem in medicine, with more infections becoming difficult to treat using traditional antimicrobial agents. The work presented here highlights the potential use of predatory bacteria as a biological‐based agent for eradicating multidrug‐resistant bacteria, with the hope of paving the way for future studies in animal models.     

Minireviews: Exploring the Basic Ecological Unit: Ecosystem-like Concepts in Traditional Societies

Ancient conceptualizations of ecosystems exist in several Amerindian, Asia-Pacific, European, and African cultures. The rediscovery by scientists of ecosystem-like concepts among traditional peoples has been important in the appreciation of traditional ecological knowledge among ecologists, anthropologists, and interdisciplinary scholars. Two key characteristics of these systems are that (a) the unit of nature is often defined in terms of a geographical boundary, such as a watershed, and (b) abiotic components, plants, animals, and humans within this unit are considered to be interlinked. Many traditional ecological knowledge systems are compatible with the emerging view of ecosystems as unpredictable and uncontrollable, and of ecosystem processes as nonlinear, multiequilibrium, and full of surprises. Traditional knowledge may complement scientific knowledge by providing practical experience in living within ecosystems and responding to ecosystem change. However, the “language” of traditional ecology is different from the scientific and usually includes metaphorical imagery and spiritual expression, signifying differences in context, motive, and conceptual underpinnings. Received 28 April 1998; accepted 9 July 1998.