外源抗虫蛋白与内源抗虫因子的交互作用

以次生代谢物质萜烯类、黄酮类以及单宁等为基础的自身化学抗虫性一直是植物化学防御的核心.随着基因重组技术的发展,许多作物获得了一种新的化学防御形式,即以表达外源基因产物来进行防御.外源抗虫蛋白与内源抗虫物质的协调性问题,在利用外源基因工程改良植物抗虫性时是非常重要的,同时也是转基因作物安全性和生态学评价的重要方面.转基因植物中外源与内源抗虫系统间的协调性的研究取得了一些成果,但尚未引起人们足够的重视.综述了离体条件下和在转基因植物体内,外源抗虫蛋白Bt和GNA等与植物次生代谢物质以及各抗虫蛋白之间交互作用的研究进展,并探讨了研究各抗虫因子交互作用的意义.     

外源抗虫蛋白与内源抗虫因子的交互作用

以次生代谢物质萜烯类、黄酮类以及单宁等为基础的自身化学抗虫性一直是植物化学防御的核心。随着基因重组技术的发展,许多作物获得了一种新的化学防御形式,即以表达外源基因产物来进行防御。外源抗虫蛋白与内源抗虫物质的协调性问题,在利用外源基因工程改良植物抗虫性时是非常重要的,同时也是转基因作物安全性和生态学评价的重要方面。转基因植物中外源与内源抗虫系统间的协调性的研究取得了一些成果,但尚未引起人们足够的重视。综述了离体条件下和在转基因植物体内,外源抗虫蛋白Bt和GNA等与植物次生代谢物质以及各抗虫蛋白之间交互作用的研究进展,并探讨了研究各抗虫因子交互作用的意义。     

Microbial diversity in soil: effect of releasing genetically engineered micro-organisms

This review examines the potential for change in microbial diversity, with the emphasis on bacteria, in soil resulting from the introduction of genetically engineered microorganisms (GEMs). With the advent of GEMs came the impetus for new technologies to recover these micro-organisms from soil and to assess their effects on microbial diversity. This review also presents general aspects of and genetic approaches to accessing bacterial diversity in the environment.     

Use of genetically engineered microorganisms (GEMs) for the bioremediation of contaminants

This paper presents a critical review of the literature on the application of genetically engineered microorganisms (GEMs) in bioremediation. The important aspects of using GEMs in bioremediation, such as development of novel strains with desirable properties through pathway construction and the modification of enzyme specificity and affinity, are discussed in detail. Particular attention is given to the genetic engineering of bacteria using bacterial hemoglobin (VHb) for the treatment of aromatic organic compounds under hypoxic conditions. The application of VHb technology may advance treatment of contaminated sites, where oxygen availability limits the growth of aerobic bioremediating bacteria, as well as the functioning of oxygenases required for mineralization of many organic pollutants. Despite the many advantages of GEMs, there are still concerns that their introduction into polluted sites to enhance bioremediation may have adverse environmental effects, such as gene transfer. The extent of horizontal gene transfer from GEMs in the environment, compared to that of native organisms including benefits regarding bacterial bioremediation that may occur as a result of such transfer, is discussed. Recent advances in tracking methods and containment strategies for GEMs, including several biological systems that have been developed to detect the fate of GEMs in the environment, are also summarized in this review. Critical research questions pertaining to the development and implementation of GEMs for enhanced bioremediation have been identified and posed for possible future research.     

Use of Genetically Engineered Microorganisms (GEMs) for the Bioremediation of Contaminants

ABSTRACT

This paper presents a critical review of the literature on the application of genetically engineered microorganisms (GEMs) in bioremediation. The important aspects of using GEMs in bioremediation, such as development of novel strains with desirable properties through pathway construction and the modification of enzyme specificity and affinity, are discussed in detail. Particular attention is given to the genetic engineering of bacteria using bacterial hemoglobin (VHb) for the treatment of aromatic organic compounds under hypoxic conditions. The application of VHb technology may advance treatment of contaminated sites, where oxygen availability limits the growth of aerobic bioremediating bacteria, as well as the functioning of oxygenases required for mineralization of many organic pollutants. Despite the many advantages of GEMs, there are still concerns that their introduction into polluted sites to enhance bioremediation may have adverse environmental effects, such as gene transfer. The extent of horizontal gene transfer from GEMs in the environment, compared to that of native organisms including benefits regarding bacterial bioremediation that may occur as a result of such transfer, is discussed. Recent advances in tracking methods and containment strategies for GEMs, including several biological systems that have been developed to detect the fate of GEMs in the environment, are also summarized in this review. Critical research questions pertaining to the development and implementation of GEMs for enhanced bioremediation have been identified and posed for possible future research.     

基因工程微生物的环境监测及生物防御体系研究进展

随着生物技术的发展, 研究人员构建出了大量具有特定功能的基因工程微生物, 这些基因工程微生物在实际应用时常受到限制, 因为它们释放到环境中有可能带来新的污染。为了减少或消除其对环境的潜在危害, 有必要采取措施对这些基因工程微生物进行监测和安全控制。通常要求这类基因工程微生物带有便于监测的检测标记以及能进行自消亡的主动生物防御体系。对基因工程微生物的检测标记以及主动生物防御体系的研究现状进行了综述。     

基因工程微生物的环境监测及生物防御体系研究进展

随着生物技术的发展, 研究人员构建出了大量具有特定功能的基因工程微生物, 这些基因工程微生物在实际应用时常受到限制, 因为它们释放到环境中有可能带来新的污染。为了减少或消除其对环境的潜在危害, 有必要采取措施对这些基因工程微生物进行监测和安全控制。通常要求这类基因工程微生物带有便于监测的检测标记以及能进行自消亡的主动生物防御体系。对基因工程微生物的检测标记以及主动生物防御体系的研究现状进行了综述。     

近10年外来入侵昆虫风险分析的研究现状及主要进展

随着经济全球化的加速发展,外来入侵昆虫对世界各国农林业、生态环境、社会经济和人类健康造成的影响日趋严重。近10年来,关于外来入侵昆虫风险分析的相关研究备受重视,发展迅速;在研究对象类别中,鞘翅目昆虫居多,占所有入侵昆虫的32.21%,其次为双翅目和膜翅目,最小的为缨翅目,仅占1.44%。风险分析主要包括入侵途径、适生范围及风险等级、传播扩散、经济和生态影响等层面;其中以适生性风险分析研究最多,占43.41%。深入开展入侵昆虫的风险分析,对防范和阻截其传入、扩散和蔓延具有重要的理论意义和应用价值。     

How to evaluate the environmental safety of microbial plant protection products: A proposal

Plant protection products with active micro-organisms are allegedly less hazardous to the environment and wildlife than synthetic chemical pesticides. Nevertheless, they need a proper pre-marketing environmental safety evaluation because of their potential toxicity and pathogenicity. Scientific and technical guidance on such a safety evaluation for regulatory purposes is scarce. Therefore, a risk decision tree is proposed to provide such guidance and to discern the acceptable from the unacceptable environmental risks. The decision tree is based on the risk criteria of the European Union. It takes integrally into account the characterisation, identification and efficacy and also emission, exposure, environmental effects and, finally, the environmental risk assessment. Case by case expert judgement remains necessary in view of limited knowledge of microbial ecology, limited experience with regulatory test protocols and taxonomic difficulties in relation to the indigenousness of active micro-organisms. The decision tree offers regulatory guidance on the environmental safety evaluation of microbial plant protection products.     

Effects of Genetically Engineered Microorganisms on Nitrogen Transformations and Nitrogen-Transforming Microbial Populations in Soil

The principal concern about releasing genetically engineered microorganisms (GEMs) into the environment is their potential adverse effects on the environment, whether caused directly or indirectly by the GEMs. The effects of five GEMs on ammonification, nitrification, and denitrification in soil were studied. With the possible exception of a strain of Enterobacter cloacae carrying a plasmid, no consistent statistically or ecologically significant differences in effects on these processes or on the population dynamics of the microorganisms responsible for the processes were observed between soils inoculated with the GEMs or their homologous plasmidless hosts and those that were not inoculated. Increasing the concentration of montmorillonite in the soil enhanced the rate of nitrification, regardless of the inoculum, indicating that the perfusion technique used was sensitive enough to detect changes in nitrification rates when they occurred.     

Models to examine containment and spread of genetically engineered microbes

Genetically engineered microbes (GEMs) have the potential to revolutionize agricultural techniques by facilitating crop protection and increased productivity. However, there has been widespread concern regarding the potential impact these microbes may have on the environment. Here we mathematically model the dynamics of GEMs in an agricultural setting, focusing on parameters that can be used to summarize the potential of modified microbes for persistence and spread. First developing a comprehensive model for the dynamics of GEMs which includes mobile and stationary classes of GEMs as well as competition from indigenous microflora, we then analyse a sequence of simplified mathematical models with a view to answering two fundamental questions: (1) will the GEMs spread (or invade), and if so how quickly? and (2) what are the best strategies for containing the spread of GEMs in a spatially varying environment?     

Suicidal genetically engineered microorganisms for bioremediation: need and perspectives

In the past few decades, increased awareness of environmental pollution has led to the exploitation of microbial metabolic potential in the construction of several genetically engineered microorganisms (GEMs) for bioremediation purposes. At the same time, environmental concerns and regulatory constraints have limited the in situ application of GEMs, the ultimate objective behind their development. In order to address the anticipated risks due to the uncontrolled survival/dispersal of GEMs or recombinant plasmids into the environment, some attempts have been made to construct systems that would contain the released organisms. This article discusses the designing of safer genetically engineered organisms for environmental release with specific emphasis on the use of bacterial plasmid addiction systems to limit their survival thus minimizing the anticipated risk. We also conceptualize a novel strategy to construct "Suicidal Genetically Engineered Microorganisms (SGEMs)" by exploring/combining the knowledge of different plasmid addiction systems (such as antisense RNA-regulated plasmid addiction, proteic plasmid addiction etc.) and inducible degradative operons of bacteria.     

The impact of hybrids between genetically modified crop plants and their related species: biological models and theoretical perspectives

Forces affecting the rate of spread and increase of hybrids between genetically modified crop plants and their related species remain qualitatively similar, irrespective of whether genetic modification was achieved using traditional methods, those of biotechnology or as a result of the natural evolutionary process. However, the precise magnitude of the forces and, consequently, the likely environmental impact of such hybrids, may depend strongly on the nature of the gene or genes introduced into the native species. While many classes of transgenes are similar to those manipulated by conventional breeding techniques or evolution, biotechnology offers the potential to introduce genes into crops which are novel both from the point of view of function and origin. The qualitative similarity between transgenes and the products of conventional or evolutionary modification suggests that a historical view of the environmental impact of hybrids between traditionally produced crops or exotic species and their relatives would be of use in estimating the probable fate of hybrids containing transgenes in the environment. However, with certain classes of transgenes for which there are no existing analogues, there will need to be greater care in assessing the possible risks associated with release into the environment.     

同源重组法构建多功能农药降解基因工程菌研究

构建遗传稳定的多功能农药降解基因工程菌可以为农药污染的生物修复提供良好的菌种资源,然而,构建遗传稳定且不带入外源抗性的基因工程菌是一个难点。通过以受体菌的16S rDNA为同源重组指导序列、sacB基因为双交换正筛选标记构建同源重组载体,二亲结合的方法将甲基对硫磷水解酶基因（mpd）整合到呋喃丹降解菌Sphingomonas sp.CDS1染色体的16S rDNA位点,分别成功构建了含1个和2个mpd基因插入到rDNA位点且不带入外源抗性的基因工程菌株CDSmpd和CDS-2mpd。同源重组单交换的效率为3.7×10^－7～6.8×10^－7。通过PCR和Southern杂交的方法验证了同源重组事件。基因工程菌遗传稳定,能同时降解甲基对硫磷和呋喃丹。甲基对硫磷水解酶（MPH）的比活在各生长时期均高于原始出发菌株,比活最高达6.22 mu/μg。     

Assessing environmental risks of transgenic plants

By the end of the 1980s, a broad consensus had developed that there were potential environmental risks of transgenic plants requiring assessment and that this assessment must be done on a case-by-case basis, taking into account the transgene, recipient organism, intended environment of release, and the frequency and scale of the intended introduction. Since 1990, there have been gradual but substantial changes in the environmental risk assessment process. In this review, we focus on changes in the assessment of risks associated with non-target species and biodiversity, gene flow, and the evolution of resistance. Non-target risk assessment now focuses on risks of transgenic plants to the intended local environment of release. Measurements of gene flow indicate that it occurs at higher rates than believed in the early 1990s, mathematical theory is beginning to clarify expectations of risks associated with gene flow, and management methods are being developed to reduce gene flow and possibly mitigate its effects. Insect pest resistance risks are now managed using a high-dose/refuge or a refuge-only strategy, and the present research focuses on monitoring for resistance and encouraging compliance to requirements. We synthesize previous models for tiering risk assessment and propose a general model for tiering. Future transgenic crops are likely to pose greater challenges for risk assessment, and meeting these challenges will be crucial in developing a scientifically coherent risk assessment framework. Scientific understanding of the factors affecting environmental risk is still nascent, and environmental scientists need to help improve environmental risk assessment.     

Yeast metabolic innovations emerged via expanded metabolic network and gene positive selection

Yeasts are known to have versatile metabolic traits, while how these metabolic traits have evolved has not been elucidated systematically. We performed integrative evolution analysis to investigate how genomic evolution determines trait generation by reconstructing genome‐scale metabolic models (GEMs) for 332 yeasts. These GEMs could comprehensively characterize trait diversity and predict enzyme functionality, thereby signifying that sequence‐level evolution has shaped reaction networks towards new metabolic functions. Strikingly, using GEMs, we can mechanistically map different evolutionary events, e.g. horizontal gene transfer and gene duplication, onto relevant subpathways to explain metabolic plasticity. This demonstrates that gene family expansion and enzyme promiscuity are prominent mechanisms for metabolic trait gains, while GEM simulations reveal that additional factors, such as gene loss from distant pathways, contribute to trait losses. Furthermore, our analysis could pinpoint to specific genes and pathways that have been under positive selection and relevant for the formulation of complex metabolic traits, i.e. thermotolerance and the Crabtree effect. Our findings illustrate how multidimensional evolution in both metabolic network structure and individual enzymes drives phenotypic variations.     

国内生态安全研究知识图谱——基于Citespace的计量分析

以CSSCI中2000—2011年299篇生态安全研究论文为研究对象,采用文献共被引网络、关键词共现网络及突现词分析,以信息可视化为手段,对国内生态安全研究现状进行了分析。研究发现,目前国内生态安全研究已完成了基础理论和研究体系的架构,但研究网络过于集中,前沿分支较少。生态安全研究起源、生态安全基础理论、生态风险评价、生态系统评价、土地生态安全研究是国内生态安全研究的主要知识群组。国内生态安全研究主题集聚成3条核心路径:"生态安全基础理论研究"路径、"生态安全-生态系统评价-区域生态安全评价-生态预警"路径、"生态安全-生态风险评价-农村资源生态系统-土地生态安全研究-生态预警"路径。生态预警及土地生态安全研究成为当前生态安全的研究前沿,生态安全研究更趋向于对特色性的生态系统进行分析与评价。     

基于最大虫口限量原理的外来入侵害虫定量风险评估技术

为了保证检疫的安全性而又不失国际贸易的透明度,需要对检疫害虫进行定量的风险评估。本文介绍一套基于最高虫口限量概念的害虫传入定量风险评估计算机平台,把两性生殖害虫的入侵风险建立在至少一对潜在交配成虫的传入概率上。计算机分析平台由SAS V9.0分析软件,PHP网络编程语言和MySQL数据库构建,通过Apache服务器进行网络发布。用户通过web登陆该平台并输入相关参数,可自动调用服务器端的SAS分析程序进行分析并在网页上得到结果。这是害虫传入风险定量评估的新尝试,它将为检疫部门提供一套实用性较强的害虫传入风险量化评估的新工具。     

A secondary effect of transformation in Rhizobium leguminosarum transgenic for Bacillus thuringiensis subspecies tenebrionisδ-endotoxin (cryIIIA) genes

 By introducing Bacillus thuringiensis subspecies tenebrionisδ-endotoxin genes (cryIIIA) into Rhizobium leguminosarum we have produced strains for the biological control of Sitona larvae. Comparisons between a transgenic and the parent strain show that transformation has induced changes not associated with the intended function of the transgene. Although growth rates in laboratory cultures are similar for both strains, the ability to compete for nodule occupancy is greater in the transgenic than in the non-transformed parent strain. This result demonstrates the importance of studying ecological and agronomic characters of transgenic micro-organisms that could have a bearing on the safety and success of their release into the environment, even if they are not thought to be connected with the transgenes introduced. Received: 20 April 1997 / Accepted: 2 June 1997     

Natural products potential of Dictyoceratida sponges-associated micro-organisms

The marine environment represents one of the most underexplored environments in the world. Marine sponges have a higher taxonomic diversity according to definite environmental conditions. They have been considered interesting sources for bioactive compounds. Dictyoceratida sponges are divided into five families which are widely distributed and habituating different types of micro-organisms. However, some secondary metabolites are probably not produced by the sponges themselves, but rather by their associated micro-organisms. These secondary metabolites are characterized by different chemical structures and consequently different biological activities. This review outlines the reported secondary metabolites from micro-organisms associated with Dictyoceratida sponges and their investigated biological activities from 1991 to 2019. The increasing research studies in this field can play a major role in marine microbial natural products drug discovery in the future.