Drosophila melanogaster as an emerging model host for entomopathogenic fungi

Entomopathogenic fungi (EPF) infect insects and are of interest for understanding host-pathogen interactions and biological control of insect pests. The fruit fly Drosophila melanogaster offers an excellent model system for exploring the biology of EPF and their interactions with insects. In this review, we describe the advantages of using D. melanogaster as a model system to study EPF and highlight EPF of relevance to agriculture. We also propose possible directions for future research in this area. We predict that in the future, D. melanogaster will continue to be a productive system for understanding the biology of the fungi attacking insects and will no doubt contribute to the future of biological control, conservation and other areas.     

Biological Control of Infestations of Ditchweed ( Cannabis sativa ) with Fusarium oxysporum f.sp. Cannabis in Kazakhstan

Ditchweed ( Cannabis sativa L.) is widely distributed in the Chu Valley of southeast Kazakhstan and is difficult to control using conventional chemical or mechanical control. Thus, plant pathogens were investigated as potential biocontrol agents. Fusarium oxysporum was isolated from symptomatic C. sativa plants from this area. Twenty-five of the isolated strains of F. oxysporum were pathogenic and host-specific to C. sativa in greenhouse studies. These strains of F. oxysporum f. sp. cannabis were further evaluated as mycoherbicides for control of ditchweed in natural field infestations. Twelve strains showed field control of C. sativa , and the most virulent strain elicited wilt symptoms within 2 weeks of inoculation of field plants. Three different mycoherbicide formulations were evaluated. A birch sawdust formulation was the most effective carrier in the field. Food based formulations were heavily predated by birds, rodents and insects.     

Insecticidal bacteria: an overwhelming success for invertebrate pathology

The discovery and study of insecticidal bacteria, which began a little over a century ago, led to the development of commercial bacterial insecticides in the middle of the century that became the first successful and widely used microbial control agents. Most of these products were based on Bacillus thuringiensis, a bacterium that kills insects through the use of insecticidal proteins that subsequently became known as Cry proteins. While most of these products were only effective against lepidopteran pests, their success eventually led in the 1970s and 1980s to the discovery of strains effective against larvae of coleopteran pests and nematocerous dipterans, such as vector and nuisance mosquitoes and blackflies. The cloning in 1981 of the first gene encoding a Cry protein led to an explosion of basic and applied research that culminated in new strains of recombinant insecticidal bacteria and, even more importantly, the development, commercialization, and wide-scale deployment of insecticidal transgenic crops based on Cry proteins. This new and environmentally safe technology has revolutionized agricultural pest control, yielding a multibillion dollar industry that is paving the way to new types of plants that will dominate food and fiber production as the 21st century progresses. In this brief symposium paper, I provide an overview of some of the key work that led to this remarkable success.     

黑龙江省苏云金杆菌的分离及对夜蛾科昆虫高毒力菌株的筛选

【目的】为了发掘新的苏云金杆菌(Bacillus thuringiensis)的资源,在黑龙江省不同地区采集不同类型的土壤样品分离出对夜蛾科具有高毒力的菌株。【方法】采用醋酸钠选择性筛选法筛选Bt菌株,利用10对通用引物对分离株进行基因型分析,SDS-PAGE进行杀虫晶体蛋白分析,同时测定苏云金杆菌分离株对棉铃虫Helicoverpa armigera(Hübner)、甘蓝夜蛾Mamestra brassicae(Linnaeus)、斜纹夜蛾Spodoptera litura(Fabricius)的杀虫活性。【结果】从黑龙江省不同地区采集的352份不同类型的土壤样品中,共分离出46株苏云金芽孢杆菌野生菌株,出菌率为13.06%。油镜下可观察到伴孢晶体的形态有菱形、球形、镶嵌形及不规则形。结果表明产菱形晶体的菌株多含有cry1类基因,而同时产生菱形、球形及不规则形晶体的菌株则含有多种基因型。SDS-PAGE蛋白分析发现这些菌株主要表达130、90、60 ku蛋白。对其中的部分菌株进行毒力测定,结果表明有4株菌株对3种夜蛾科昆虫具有高毒力。【结论】黑龙江省苏云金芽孢杆菌分布广泛,类型多样,已获得对夜蛾科昆虫有高毒力的菌株,这对夜蛾科害虫的绿色防控及延缓其抗性具有重要意义。     

Solid formulations of binucleate Rhizoctonia isolates suppress Rhizoctonia solani and Pythium ultimum in potting medium

Two isolates of binucleate Rhizoctonia spp., previously selected for efficacy in suppression of Rhizoctonia solani and Pythium spp., as well as plant growth promotion, were incorporated into various solid substrate formulations. These formulated products were assayed at three doses in three glass-house experiments for biocontrol of damping-off diseases in Capsicum annuum. R. solani anastomosis group 4 or Pythium ultimum var. sporangiiferum were incorporated into pasteurized potting medium with each formulated binucleate Rhizoctonia product. All formulations were effective against both pathogens in at least two experiments, but some formulations of one isolate of binucleate Rhizoctonia did not give consistent control of R. solani in one experiment. The most consistent formulation, which provided control of both pathogens at all doses of binucleate Rhizoctonia, was the simple substrate of rice hulls. The implications for commercialization of a biocontrol product are discussed.     

中国植物质杀虫剂的研究(英语)

本文主要集中反映及讨论中国植物质杀虫剂近年主要的研究成果.内容包括:印楝、苦楝、川楝、黄杜鹃、毛鱼藤、非州山毛豆、紫背金盘及其它杀虫植物.还讨论了植物质杀虫剂的活性及在害虫防治上的应用.     

RESEARCH ON INSECTICIDES FROM PLANTS IN CHINA

Abstract  An overview is presented on recent (1989–19911 investigations on insecticidal plants in China, specially in South China. The main emphasis was laid on studies of Meliaceae including Azadirachta indica, Melia azedarach and M. toosendan , as well as on Rhododendron molle, Derris elliptica, Tephrosia voglii, Ajuga nipponensis, Plumbago idea and Celastrus anplatus . Research work on the bioactivities and application of essential oils from plants for the control of stored-grain insects is also discussed. The results of these investigations reveal a great potential of the active ingredients of a number of Chinese plants for integrated pest management, as well as for using these natural product models as guides for the synthesis of a novel class of insecticides.     

Current developments in microbial control of insect pests and prospects for the early 21st century

The role of microbial control in crop and forest protection and the abatement of insects of medical and veterinary importance has expanded considerably with the discovery and development of new microbial control agents and genetic improvement in bacterial and viral pathogens, and improvements in formulation, application options and compatibility with other interventions. A synopsis of the literature regarding the current use of bacteria, viruses, fungi, protozoans and nematodes as microbial control agents is presented along with speculation on their potential in the early 21st century. The most widely used of all microbial control agents isBacillus thuringiensis. The isolation within the past two decades of new strains that are larvicidal for certain Diptera and Coleoptera has increased the utility of the bacterium considerably. Further improvements in efficacy and broadening of its host range are in progress with the isolation of strains with new toxins and the manipulation ofB. thuringiensis genes that encode toxin production using both recombinant and nonrecombinant methods. Genetic manipulation of these genes has also enabled their incorporation into crop plants. The development and commercial availability of entomopathogenic nematodes in the families Steinernematidae and Heterorhabditidae expands the options for the control of insects, especially those with soil inhabiting stages. The results of natural epizootics of fungi and viruses often obviate the requirement for additional interventions. Breakthroughs in understanding the genetics ofBaculovirus and subsequent gene manipulation have increased their virulence and utility. Improved production methods that utilize insect cell culture technology may enable affordable use ofBaculovirus in the not too distant future. Fungi continue to offer the only control options using entomopathogens against plant sucking insects. Although fungi have great potential for development as microbial control agents, only a few have been used on an operational scale. Some factors that might limit the full range of entomopathogen potential, including development of resistance, are discussed. Because of their selectivity and minimal environmental impact, microbial control agents will be ideal components of integrated pest management programs in the early 21st century and beyond. However, if they are used merely as replacements for chemical pesticides, then eventually these agents will face some of the same fate as the chemicals they replace, particularly with respect to resistance.     

昆虫内共生菌沃尔巴克氏体抗病毒研究进展

植物病毒病是危害我国蔬菜生产的第一大病害,而烟粉虱Bemisia tabaci Gennadius、蓟马和蚜虫等小型昆虫是蔬菜病毒病的主要传播媒介.虫传病毒病害的防控策略复杂且难度大,目前生产上主要依赖化学农药防治介体昆虫,预防与控制蔬菜病毒病.种植户化学杀虫药剂的不合理使用、甚至滥用,导致媒介昆虫抗药性、杀虫剂污染与残留等问题,严重威胁农产品安全与生态安全.发展高效控制媒介昆虫及其传播重大病毒病害防控技术是保障食品安全、蔬菜产业健康可持续发展的迫切需求.内共生菌沃尔巴克氏体Wolbachia是节肢动物体内广泛存在并经卵传播的革兰氏阴性胞内次生共生细菌,约65％的昆虫天然携带沃尔巴克氏体.沃尔巴克氏体对宿主昆虫具有胞质不亲和、产雌孤雌生殖、雌性化或者杀雄作用等生殖调控作用,同时抑制虫媒病毒病在昆虫体内的复制和传播.基于沃尔巴克氏体的蚊媒及蚊媒病毒病控制研究与应用取得了重大进展,现就沃尔巴克氏体抗病毒及其应用的最新进展和未来发展进行综述,为发展蔬菜害虫及其传播病毒病防控技术提供新思路.     

Industrial and international standardization of microbial pesticides — I.Bacillus thuringiensis

Bacillus thuringiensis preparations are standardized by bioassay based on a comparison with a reference standard preparation. By this way the standardization of industrial formulations is satisfactory in order to maintain a constant quality within a given product. International standardization is quite another problem and cannot be achieved by facing only standardized titration methods, since other factors, particularly the used strains, contribute to different host activity. An account is given of the actual situation with historical backgrounds and some suggestions are made to avoid possible pitfall. Essentially it would be most useful to demonstrate the biological activity differences of different products. This work could be done by the different specialized laboratories with the help of internationally distributed standard preparations of each proposed serotype and using various technics and multiple test insects.     

Utilization of prebiotic carbohydrates by yeasts of therapeutic relevance

AIMS: To investigate 17 strains of therapeutically relevant strains of Saccharomyces cerevisiae (including 10 strains of so-called S. boulardii) isolated from various pharmaceutical products, feed supplements and brewer's yeast for their capability of utilizing selected carbohydrates of prebiotic importance. METHODS AND RESULTS: Automated turbidimetric measurements and conventional test combinations were used to examine the basic sugar assimilation profiles of the test strains. It was shown that none of the so-called S. boulardii strains utilized galactose and palatinose. Among the prebiotic substrates, the yeasts indicated a pronounced preference for metabolizing the fructo-oligosaccharides. CONCLUSION: Yeast strains of therapeutic relevance can be successfully combined with certain prebiotics in symbiotic formulations. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study may serve as a basis for the development of new pharmaceutical preparations for medical therapy and a better understanding of intestinal micro-ecology.     

Development of omics-based protocols for the microbiological characterization of multi-strain formulations marketed as probiotics: the case of VSL#3

The growing commercial interest in multi-strain formulations marketed as probiotics has not been accompanied by an equal increase in the evaluation of quality levels of these biotechnological products. The multi-strain product VSL#3 was used as a model to setup a microbiological characterization that could be extended to other formulations with high complexity. Shotgun metagenomics by deep Illumina sequencing was applied to DNA isolated from the commercial VSL#3 product to confirm strains identity safety and composition. Single-cell analysis was used to evaluate the cell viability, and β-galactosidase and urease activity have been used as marker to monitor the reproducibility of the production process. Similarly, these lots were characterized in detail by a metaproteomics approach for which a robust protein extraction protocol was combined with advanced mass spectrometry. The results identified over 1600 protein groups belonging to all strains present in the VSL#3 formulation. Of interest, only 3.2 % proteins showed significant differences mainly related to small variations in strain abundance. The protocols developed in this study addressed several quality criteria that are relevant for marketed multi-strain products and these represent the first efforts to define the quality of complex probiotic formulations such as VSL#3.     

Modification of arthropod vector competence via symbiotic bacteria

Some of the world's most devastating diseases are transmitted by arthropod vectors. Attempts to control these arthropods are currently being challenged by the widespread appearance of insecticide resistance. It is therefore desirable to develop alternative strategies to complement existing methods of vector control. In this review, Charles Beard, Scott O'Neill, Robert Tesh, Frank Richards and Serap Aksoy present an approach for introducing foreign genes into insects in order to confer refractoriness to vector populations, ie. the inability to transmit disease-causing agents. This approach aims to express foreign anti-parasitic or anti-viral gene products in symbiotic bacteria harbored by insects. The potential use of naturally occurring symbiont-based mechanisms in the spread of such refractory phenotypes is also discussed.     

冬虫夏草培植技术研究进展

本文对近年来冬虫夏草的培植,包括菌种分离培养、寄主饲养、侵染机理、接种方法及子实体发育条件等研究进展进行了综述。本研究组成功实现了冬虫夏草培植产业化,所培植的冬虫夏草与野生冬虫夏草在虫种、菌种、外观形态、显微结构和化学成分等方面一致。最后分析了冬虫夏草培植技术现阶段存在的问题,并对未来进行了展望。     

拟除虫菊酯类杀虫剂对蜜蜂的毒性和影响

蜜蜂是最重要的农业授粉昆虫之一,蜜蜂在授粉过程中极有可能接触到广泛使用的广谱杀虫剂-拟除虫菊酯,大多数拟除虫菊酯对蜜蜂等农业授粉昆虫有较高的毒性.本文对拟除虫菊酯类杀虫剂的作用机理进行了综述;总结了蜂群及蜂产品中拟除虫菊酯类杀虫剂的残留现状、拟除虫菊酯对蜜蜂的急性毒性以及亚致死效应,讨论了拟除虫菊酯类杀虫剂复配农药对蜜...     

Comparison of Three Products Based on Phlebiopsis gigantea for the Control of Heterobasidion annosum in Europe

The fungus Phlebiopsis gigantea has been used in Europe as a biological agent for the control of conifer root and butt (caused by Heterobasidion annosum ) for nearly 40 years. P. gigantea competes with H. annosum for the woody resource within conifer stumps, and is applied to stump surfaces at felling. Three distinct biological control products based on P. gigantea have been developed: PG Suspension in the UK, PG IBL in Poland and Rotstop in Finland. The formulations are of oidia, which are maintained in a sucrose suspension, sawdust, or a wettable powder, respectively. PG Suspension and PG IBL are applied to pine stumps, while Rotstop is equally as effective on pine as on Norway spruce stumps. For each product, isolates of P. gigantea are selected from the wild and are screened for their competitive ability against H. annosum before formulation. Viability and purity checks are undertaken throughout the production cycle and during routine use. The increasing use of mechanized harvesting machines to fell and process trees is having an impact on this biological control system, the formulations having to be compatible with the mechanical application systems and vice versa. This paper compares the formulation, testing and application of the three products, and considers some aspects of their future development.     

The use of lactic acid-producing,malic acid-producing,or malic acid-degrading yeast strains for acidity adjustment in the wine industry

In an era of economic globalization, the competition among wine businesses is likely to get tougher. Biotechnological innovation permeates the entire world and intensifies the severity of the competition of the wine industry. Moreover, modern consumers preferred individualized, tailored, and healthy and top quality wine products. Consequently, these two facts induce large gaps between wine production and wine consumption. Market-orientated yeast strains are presently being selected or developed for enhancing the core competitiveness of wine enterprises. Reasonable biological acidity is critical to warrant a high-quality wine. Many wild-type acidity adjustment yeast strains have been selected all over the world. Moreover, mutation breeding, metabolic engineering, genetic engineering, and protoplast fusion methods are used to construct new acidity adjustment yeast strains to meet the demands of the market. In this paper, strategies and concepts for strain selection or improvement methods were discussed, and many examples based upon selected studies involving acidity adjustment yeast strains were reviewed. Furthermore, the development of acidity adjustment yeast strains with minimized resource inputs, improved fermentation, and enological capabilities for an environmentally friendly production of healthy, top quality wine is presented.     

Genetic elimination of field-cage populations of Mediterranean fruit flies

The Mediterranean fruit fly (medfly, Ceratitis capitata Wiedemann) is a pest of over 300 fruits, vegetables and nuts. The sterile insect technique (SIT) is a control measure used to reduce the reproductive potential of populations through the mass release of sterilized male insects that mate with wild females. However, SIT flies can display poor field performance, due to the effects of mass-rearing and of the irradiation process used for sterilization. The development of female-lethal RIDL (release of insects carrying a dominant lethal) strains for medfly can overcome many of the problems of SIT associated with irradiation. Here, we present life-history characterizations for two medfly RIDL strains, OX3864A and OX3647Q. Our results show (i) full functionality of RIDL, (ii) equivalency of RIDL and wild-type strains for life-history characteristics, and (iii) a high level of sexual competitiveness against both wild-type and wild-derived males. We also present the first proof-of-principle experiment on the use of RIDL to eliminate medfly populations. Weekly releases of OX3864A males into stable populations of wild-type medfly caused a successive decline in numbers, leading to eradication. The results show that genetic control can provide an effective alternative to SIT for the control of pest insects.     

遗传不育技术在蚊媒疾病防控中的应用

疟疾、登革热等重大传染性蚊媒疾病严重危害人类健康,且目前缺乏有效的药物和疫苗,防治埃及伊蚊、冈比亚按蚊等媒介昆虫是控制和消除这些疾病的有效手段。化学杀虫剂的大规模使用在一定程度上控制了疾病的传播,但其抗药性和环境污染等问题也随之而来。分子生物学的飞速发展为昆虫不育技术(SIT)的更新及害虫防治提供了新的策略,由此发展起来的以释放携带显性致死基因昆虫(RIDL)为代表的一系列遗传不育技术为蚊虫种群防控提供了更加有效的选择。本文概述了遗传技术在蚊虫防控中的应用进展,包括蚊虫遗传防治的历史和策略,阐述了RIDL技术体系的原理,同时介绍了相关遗传控制品系和已经开展的田间释放研究,展示了遗传修饰不育技术在蚊媒疾病防治中的巨大潜力。     

Effectiveness of spinosad against seven major stored-grain insects on corn

In January 2005, the United States Environmental Protection Agency registered spinosad as a stored grain protectant. No referenced data on the efficacy of spinosad on corn in suppressing major stored-grain insects have been published. In this paper, we evaluated the efficacy of spinosad against seven major stored-grain insects on shelled corn in the laboratory. Insect species tested were the red flour beetle, Tribolium castaneum （Jacquelin duVal）; rusty grain beetle, Cryptolestesferrugineus （Stephens）; lesser grain borer, Rhyzopertha dominica （F.）; sawtoothed grain beetle, Oryzaephilus surinamensis （L.）; rice weevil, Sitophilus oryzae （L.）; maize weevil, Sitophilus zeamais （Motschulsky）; and Indian meal moth, Plodia interpunctella （Htibner）. Corn kernels were treated with spinosad at 0, 0. 1, 0.5, 1, and 2 active ingredient （a.i.） mg/kg for controlling the seven species. Beetle adults or P. interpunctella eggs were introduced into each container holding 100 g of untreated or insecticide-treated corn. The seven insect species survived well on the control treatment, produced 28 to 336 progeny, and caused significant kernel damage after 49 days. On spinosad-treated corn, adult mortality of C. ferrugineus, R. dominica, 0. surinamensis, S. oryzae, and S. zeamais was 〉 98% at 1 and 2 mg/kg after 12 days. Spinosad at≥ 0.5 mg/kg completely suppressed egg-to-larval survival after 21 days and egg-to-adult emergence of P. interpunctella after 49 days, whereas 16% T. castaneum adults survived at 1 mg/kg after 12 days. Spinosad at 1 or 2 mg/kg provided complete or near complete suppression of progeny production and kernel damage of all species after 49 days. Our results indicate that spinosad at the current labeled rate of 1 mg/kg is effective against the seven stored-grain insect pests on corn.