磺酰脲类除草剂残留的微生物降解研究进展

磺酰脲类除草剂是一类高效、低毒和高选择性的除草剂, 此类除草剂能有效地防除阔叶杂草, 其中有些品种对禾本科杂草也有抑制作用。由于该类除草剂易残留药害及容易对地表水造成污染, 因而其在环境中的持久性和环境安全性备受人们关注。本文综述了磺酰脲类除草剂的应用概况及其作用机理、降解磺酰脲类除草剂的常见微生物种类及影响微生物降解效率的因素, 最后展望了微生物修复技术与抗除草剂的转基因作物是解决除草剂残留药害的最佳途径。     

二硝基苯胺类除草剂微生物降解研究进展

二硝基苯胺类除草剂是一类广谱、高效且广泛使用的除草剂,微生物的降解代谢作用是其在环境中消解的最主要因素。分离筛选除草剂的高效降解菌株、分析其降解途径并阐明其微生物降解机制,可为除草剂残留污染的微生物降解修复提供理论依据和优良的降解菌株、降解基因和酶资源。本文简述了二硝基苯胺类除草剂的微生物降解菌株、降解代谢途径和降解基因/酶的研究进展,为进一步研究该类除草剂的微生物降解及其污染生物修复提供理论依据和资源。     

二苯醚类除草剂的微生物降解研究进展

二苯醚类除草剂是一类广谱、高效、高选择性的除草剂,广泛应用于大豆、花生等农田一年生和多年生阔叶杂草的防除。由于该类除草剂不易降解,多年连续使用会导致其在土壤环境中的大量积累。本文概述了二苯醚类除草剂的基本结构及其对生物的影响,总结了降解二苯醚类除草剂的微生物种类、降解途径和降解过程中关键酶及其基因,分析了影响微生物降解二苯醚类除草剂的因素,对二苯醚类除草剂微生物降解未来的研究方向进行了展望,为深入研究二苯醚类除草剂的生物降解提供参考。     

取代脲类除草剂的微生物降解

取代脲类除草剂主要用来防除一年生禾本科杂草和阔叶杂草,自20世纪中期推入市场以来,在世界范围内被广泛使用,已成为重要的除草剂之一。随着取代脲类除草剂的持续施用,其在环境中的残留严重超标,危害日益凸显。因此,取代脲类除草剂在环境中的吸附、迁移和降解等行为备受关注。研究表明细菌降解N,N-二甲基取代脲类除草剂主要是通过连续脱甲基作用后断脲桥降解,而降解N-甲氧基-N-甲基取代脲类除草剂是通过脲桥的直接断裂。真菌降解取代脲类除草剂的途径则较为复杂,尚需进一步阐明。本文综述了近年来分离筛选的取代脲类除草剂降解菌株及其降解途径的最新研究进展,为取代脲类除草剂污染环境的生物修复研究提供参考。     

微生物降解磺酰脲类除草剂的研究进展

磺酰脲类除草剂是一种高效、广谱、高选择性的除草剂,但其长期广泛使用对生态环境造成了严重破坏,因此对于如何科学合理使用磺酰脲类除草剂、有效防治作物药害和降低对人类的危害等问题成为近年来的研究热点。磺酰脲除草剂在土壤中以化学降解和生物降解方式为主,生物降解是自然界本身具有的一种降解污染物的方式,是一种可行性高、副作用小的方法。近年来,很多学者已经开始研究并利用真菌、细菌等微生物来降解磺酰脲类除草剂,取得了许多重要结果。本文总结了磺酰脲类除草剂的性质、结构以及降解机理、可降解该类除草剂的微生物种类和影响微生物降解效率的因素;最后指出了现阶段存在的问题并对磺酰脲类除草剂的未来发展趋势进行展望。     

甲氧基丙烯酸酯类农药生态毒理及其微生物降解研究进展

近年来,随着甲氧基丙烯酸酯类农药用量的不断增加,其产生的农药残留污染问题已引起社会的广泛关注。如何有效治理甲氧基丙烯酸酯类农药的残留污染是科研工作者亟待解决的问题。生物修复技术以其高效、廉价、安全等优点,已成为消除农药残留污染的有效措施。综述了甲氧基丙烯酸酯类农药的生态毒理及其微生物降解的研究现状,介绍该类农药代谢产物及基本降解途径,分析甲氧基丙烯酸酯类农药残留污染微生物降解存在的问题并提出发展方向,为解决该类农药残留污染危害提供技术参考。     

抗咪唑啉酮类除草剂水稻种质的筛选鉴定

咪唑啉酮类除草剂是一类广谱高效除草剂,其作用靶标是乙酰乳酸合成酶(ALS,acetolactate synthase)。培育抗咪唑啉酮类除草剂水稻品种是防治直播稻田杂草危害的有效途径之一。本研究通过喷施咪唑啉酮类除草剂,从30570份水稻种质资源中,获得1份抗咪唑啉酮类除草剂的水稻新种质,该材料抗性性状稳定、抗性效应明显,序列分析表明其ALS基因编码区第1880位的G/A突变导致第627位氨基酸由丝氨酸改变为天冬酰胺,从而产生抗性。本研究发现的抗除草剂新材料,为选育抗除草剂水稻新品种奠定了种质基础。     

化学除草剂对农田生物群落的影响

从直接作用和间接作用两个方面,在个体、种群和群落3个水平上综述了化学除草剂对农田植物、动物和微生物群落的影响,并提出了今后需要加强研究的几个问题(1)残留在作物和杂草植株内的除草剂及其代谢产物通过食物链和生物富集作用对农田动物群落各级消费者造成的影响;(2)非作物生境使用化学除草剂对毗邻作物生境天敌群落的影响,以及作物生境使用除草剂对邻近非作物生境天敌群落的影响;(3)由除草剂长期使用引起的杂草群落演替、多样性下降、地表覆盖物和地下生物量减少对土壤动物和微生物群落的物种组成、分布、丰富度及其生态功能的影响;(4)化学除草剂与杀虫剂和化肥等其他农用化学品对农田生物群落的联合作用。     

除草剂的微生物降解研究进展

微生物降解是环境中农药消解的重要因素,分离筛选纯培养的农药降解微生物并阐述其降解机制为微生物修复环境的应用提供重要的菌株资源和理论依据。本文简述了广泛使用的8类除草剂(包括有机磷类、磺酰脲类、氯乙酰胺类、均三嗪类、芳氧基苯氧基丙酸酯类、苯氧乙酸类、二硝基苯胺类和硫代氨基甲酸酯类除草剂)的降解微生物资源及其降解途径和降解基因的研究进展,并分析了目前除草剂污染修复存在的问题及未来的发展方向。     

氟喹诺酮类抗生素及耐药基因污染控制的研究进展北大核心CSCD

氟喹诺酮类抗生素属于喹诺酮类抗生素,是一类人畜通用的抗生素。近年来,被广泛应用于人类和畜牧、水产等养殖业领域,然而其大量使用,造成在环境中的不断残留和累积,给自然环境和人类健康造成了较大威胁。现有研究表明,微生物降解是有效去除氟喹诺酮类抗生素残留污染的有效方法之一。本文总结和介绍了近年来氟喹诺酮类抗生素微生物降解单株菌和混合菌群、微生物降解酶、降解途径以及微生物降解氟喹诺酮类抗生素的实际应用,并对目前氟喹诺酮类抗生素微生物降解研究中存在的问题进行了分析,以及对未来氟喹诺酮类抗生素微生物降解研究的重点进行了探讨,以期为后续的研究提供参考。     

Positive plant microbial interactions

Problems and concerns in relation to the use of inorganic fertilisers, irrigation, herbicides and pesticides have led to the search for alternative strategies to combat limiting soil nutrient and water levels and the effect of weeds and pests on crops. Greater utilisation of microorganisms in agricultural systems could possibly allow reductions in the use of inorganic fertilisers, water, herbicides and pesticides with no impact on crop yield. Positive plant microbial interactions which are currently under study are considered here.     

Interactions between national and local strategies for the management of aquatic weeds

Management of aquatic weeds is often handled primarily at the local level. However, both water and water weeds do not recognise political boundaries even when these coincide with rivers or catchment areas. Thus potentially effective management of a weed in one area may be undermined by absence of a complementary program of management in an adjacent area. Authorities in each of the eight States or Territories that make up Australia are separately responsible for managing water weeds in their own State or Territory. Originally there was little coordination of these programs, but during the 1980s a national strategy for control of Australian water weeds has been progressively devised and put into practice. This stresses prevention and includes policies on plant importation, nomination of noxious weeds, development of a research strategy, a public awareness campaign, guidelines on the use of herbicides in or near water, and a field guide. This strategy is currently being incorporated into a National Weeds Strategy.     

Degradation of Herbicides in the Tropical Marine Environment: Influence of Light and Sediment

Widespread contamination of nearshore marine systems, including the Great Barrier Reef (GBR) lagoon, with agricultural herbicides has long been recognised. The fate of these contaminants in the marine environment is poorly understood but the detection of photosystem II (PSII) herbicides in the GBR year-round suggests very slow degradation rates. Here, we evaluated the persistence of a range of commonly detected herbicides in marine water under field-relevant concentrations and conditions. Twelve-month degradation experiments were conducted in large open tanks, under different light scenarios and in the presence and absence of natural sediments. All PSII herbicides were persistent under control conditions (dark, no sediments) with half-lives of 300 d for atrazine, 499 d diuron, 1994 d hexazinone, 1766 d tebuthiuron, while the non-PSII herbicides were less persistent at 147 d for metolachlor and 59 d for 2,4-D. The degradation of herbicides was 2–10 fold more rapid in the presence of a diurnal light cycle and coastal sediments; apart from 2,4-D which degraded more slowly in the presence of light. Despite the more rapid degradation observed for most herbicides in the presence of light and sediments, the half-lives remained > 100 d for the PS II herbicides. The effects of light and sediments on herbicide persistence were likely due to their influence on microbial community composition and its ability to utilise the herbicides as a carbon source. These results help explain the year-round presence of PSII herbicides in marine systems, including the GBR, but more research on the transport, degradation and toxicity on a wider range of pesticides and their transformation products is needed to improve their regulation in sensitive environments.     

Application of Brassinosteroid Mimetics Improves Growth and Tolerance of Maize to Nicosulfuron Toxicity

Journal of Plant Growth Regulation - Pesticide residues, especially for herbicides, often damage crops, except for weeds, which results in reduced production or even death in agriculture....     

环境激素类有机污染物的微生物降解和药物类化合物的残留问题

合成有机物在环境中的残留和危害已不仅仅局限于其毒性、富集、致畸和致突变,同时还能干扰包括人类在内的生物的内分泌调节作用.近年来发达国家已开始逐渐有了环境方面的条例,限制和控制这类化合物在水及食物链中的含量.现已清楚地知道,部分除草剂和杀虫剂(如阿特拉津、DDT),塑料的添加增塑剂均有内分泌激素活性,从而对生物的正常生长发育造成不良的影响.而这些化合物不但广泛存在于环境中,在特定的环境中其含量更是非常之高.以增塑剂邻苯二甲酸和邻苯二甲酸二甲酯为例,它们在填埋渗出液中的含量可高达10g·L^-1.在我们研究这类化合物的微生物降解时发现,从活性污泥和红树林中富集到的好氧微生物能将这类化合物完全矿化,且反应速度很快.同时也发现,在降解邻苯二甲酸二甲酯时,单一的纯菌不能完全降解这类化合物,而二种或三种组合的纯菌可以在一周内将500mg·L^-1的底物完全矿化.我们已分离、鉴定出中间产物,建立起了降解途径.研究的结果证实,邻苯二甲酸二甲酯类环境激素是能够在排放前通过微生物的作用达到完全矿化的.另一方面,药物类化合物的残留问题也是一个逐渐显现出的环境问题,这方面的研究应引起更多的关注和重视.     

Microbiological and Biotechnological Aspects of Metabolism of Carbamates and Organophosphates

Abstract

Several carbamate and organophosphate compounds are used to control a wide variety of insect pests, weeds, and disease-transmitting vectors. These chemicals were introduced to replace the recalcitrant and hazardous chlorinated pesticides. Although newly introduced pesticides were considered to be biodegradable, some of them are highly toxic and their residues are found in certain environments. In addition, degradation of some of the carbamates generates metabolites that are also toxic. In general, hydrolysis of the carbamate and organophosphates yields less toxic metabolites compared with the metabolites produced from oxidation. Although microorganisms capable of degrading many of these pesticides have been isolated, knowledge about the biochemical pathways and respective genes involved in the degradation is sparse. Recently, a great deal of interest in the mechanisms of biodegradation of carbamate and organophosphate compounds has been shown because (1) an efficient mineralization of the pesticides used for insect control could eliminate the problems of environmental pollution, (2) a balance between degradation and efficacy of pesticides could result in safer application and effective insect control, and (3) knowledge about the mechanisms of biodegradation could help to deal with situations leading to the generation of toxic metabolites and bioremediation of polluted environments. In addition, advances in genetic engineering and biotechnology offer great potential to exploit the degradative properties of microorganisms in order to develop bioremediation strategies and novel applications such as development of economic plants tolerant to herbicides. In this review, recent advances in the biochemical and genetic aspects of microbial degradation of carbamate and organophosphates are discussed and areas in need of further investigation identified.