持续治理飞蝗灾害的新对策

该文通过对飞蝗Locusta migratoria为害特性的描述以及本世纪我国飞蝗防治历史的回顾,对各个时期的飞蝗治理策略的特点及不足进行了分析,并在总结我国近几年飞蝗生物治理理论研究与实践的基础上,提出了21世纪我国飞蝗生物治理的对策,即逐步扩大采用生物防治措施,增强如蝗虫微孢子虫生物防治制剂及天敌的控制作用,在飞蝗虫口密度中等或较低时,采用生物防治制剂为主,阻止或延缓中、低密度的飞蝗向高密度群居型的发展进程;在飞蝗虫口密度高时,可采用化防(昆虫生长调节剂等)与生防(如微孢子虫)配合使用,以迅速压低虫口密度,防治其迁飞为害,同时也可使蝗虫微孢子虫疾病长期流行于蝗群中,抑制飞蝗种群数量的增长。并积极探讨信息化合物对飞蝗行为的调控作用。     

Antimicrobial aromatic polyketides: a review of their antimicrobial properties and potential use in plant disease control

Aromatic polyketides are secondary metabolites widely found in bacteria, fungi, and plants, which are well-known for their diverse chemical structures and biological functions. The structural diversity of aromatic polyketides arises from a series of enzymatic modifications of the linear poly-β-ketone intermediates during biosynthesis. Their versatile bioactivities are exemplified by reports of their use as antibacterials, antifungals, antivirals, and antiparasitics. Despite many reports on the antimicrobial nature of aromatic polyketides, their potential use as plant disease control agents has still not been systematically explored and discussed. This review highlights examples of the use of aromatic polyketides as plant disease control agents and discusses their function and merits as agrochemicals.     

Production and use of biological pest control agents

Biological pest control agents are gaining prominence for the control of insect pests in agriculture and forestry. The shift from chemical control has been due to environmental concerns and recent innovations in biotechnology. Production and use of biological insect control agents is the challenge of the future for pest management.     

Emerging concepts in molecular MRI

Molecular magnetic resonance imaging (MRI) offers the potential to image some events at the cellular and subcellular level and many significant advances have recently been witnessed in this field. The introduction of targeted MR contrast agents has enabled the imaging of sparsely expressed biological targets in vivo. Furthermore, high-throughput screens of nanoparticle libraries have identified nanoparticles that act as novel contrast agents and which can be targeted with enhanced diagnostic specificity and range. Another class of magnetic nanoparticles have also been designed to image dynamic events; these act as 'switches' and could be used in vitro, and potentially in vivo, as biosensors. Other specialized MR probes have been developed to image enzyme activity in vivo. Lastly, the use of chemical exchange and off-resonance techniques have been developed, adding another dimension to the broad capabilities of molecular MRI and offering the potential of multispectral imaging. These and other advances in molecular MRI offer great promise for the future and have significant potential for clinical translation.     

Select agent regulations

In recent years, there has been an increase in research with biological agents, particularly those that pose a potential for use by terrorists. In this environment, laws have been enacted and regulations developed to ensure the appropriate use of specified "select agents and toxins" for legitimate research. Within this regulatory environment, it has been necessary for institutions and investigators to adapt to an entirely new set of requirements to begin or continue to work with these pathogens. Registration and approval for use of select agents and toxins, security and safety requirements, and daunting record-keeping requirements are only some of the regulatory challenges that researchers face in working with these agents. A brief overview of recent regulations is presented, as well as where to obtain additional information on regulations, standards, and guidelines related to work with select agents and toxins.     

On the Trail of Atmospheric Mutagens and Carcinogens: A Combined Chemical/Microbiological Approach

Major ecological problems of our polluted troposphere includeairborne toxic chemicals, acid rain and photochemical smog,all three of which are now recognized as being closely relatedchemical phenomena. We also recognize that inorder to developcost-effective strategies for their control, which protect publichealth and the environment, there must be close scientific interactionsbetween chemists and biological scientists. For example, ofrapidly emerging importance is the development of risk assessmentevaluations for specific aspects of each of these problem areas.In preparing such assessments, chemists must define the "exposure,"and biological scientists the "effects." In this paper, I discuss an example of how such close interactionsproved indispensible in our search for atmospheric mutagensand carcinogens. Thus, an integrated chemical/ microbiologicalprocedure for the isolation and identificationof particulatechemical mutagens in respirable diesel soot and ambient particlesis described. Emphasis is placed on our use of the short-term,Ames Salmonella typhimurium bacterial mutagenicity test as arapid, and relatively inexpensive, means of following the biologicalactivities of these environmental mutagens through the chemicalsteps of their separation, isolation and identification fromhighly complex environmental samples. Possible mechanisms offormation of these particulate mutagens are discussed. Theyinclude the reactions of polycyclic aromatic hydrocarbons presenton the surfaces of combustion-generated particles with gaseousco-pollutants such as nitrogen dioxide plus nitric acid, andozone. In discussing this research on a societally "relevant" problem,we illustrate the importance of "Science as a Way of Knowing."We further suggest that this integrated approach to scientificproblem solving by chemical and biological scientists mightserve as an example of a discussion topic on human ecology forundergraduate courses in the natural sciences.     

Effects of dispersal on local population increase

Work to date on biological invasions and the spread of biological control agents has been focused on the explicitly spatial aspects, such as rate of spread and shape of the wave front. There has been relatively little attention paid to the influence of dispersal on the rate of increase of local populations. We use a simple general model for logistic local growth and one-dimensional diffusive dispersal to show that dispersal can act as a substantial drain on local populations. Local increase at a site of introduction is always slower than would be expected in the absence of dispersal, while the rate of increase of other populations is initially enhanced, then reduced by dispersal. This may have an important effect when estimating population parameters for invading organisms or biological control agents during the initial stages of their spread, and helps explain the "latent period" typically observed in biological invasions.     

Integration of Herbicides with Arthropod Biocontrol Agents for Weed Control

Classical biological control of weeds using arthropods is being attempted on a large scale in a number of countries, sometimes with spectacularly successful outcomes. However, in many cases biocontrol is not completely effective and use of herbicides on weeds continues to occur, either in the presence of biocontrol agents or as an alternative to them. The ways in which the two techniques may interact are discussed, including direct toxicity of herbicides to biocontrol agents, responses to death of host plants and responses to sublethal changes caused by herbicides with different modes of action. A literature review for selected weed taxa showed that the great majority of publications relate to either chemical or to biological control techniques separately, with integration of the two seldom addressed. Possible reasons for this situation are discussed and some suggestions for future priorities are made.     

Recombinant entomopathogenic agents: a review of biotechnological approaches to pest insect control

Although the use of chemical pesticides has decreased in recent years, it is still a common method of pest control. However, chemical use leads to challenging problems. The harm caused by these chemicals and the length of time that they will remain in the environment is of great concern to the future and safety of humans. Therefore, developing new pest control agents that are safer and environmentally compatible, as well as assuring their widespread use is important. Entomopathogenic agents are microorganisms that play an important role in the biological control of pest insects and are eco-friendly alternatives to chemical control. They consist of viruses (non-cellular organisms), bacteria (prokaryotic organisms), fungi and protists (eukaryotic organisms), and nematodes (multicellular organisms). Genetic modification (recombinant technology) provides potential new methods for developing entomopathogens to manage pests. In this review, we focus on the important roles of recombinant entomopathogens in terms of pest insect control, placing them into perspective with other views to discuss, examine and evaluate the use of entomopathogenic agents in biological control.     

Biological control and sustainable food production

The use of biological control for the management of pest insects pre-dates the modern pesticide era. The first major successes in biological control occurred with exotic pests controlled by natural enemy species collected from the country or area of origin of the pest (classical control). Augmentative control has been successfully applied against a range of open-field and greenhouse pests, and conservation biological control schemes have been developed with indigenous predators and parasitoids. The cost-benefit ratio for classical biological control is highly favourable (1:250) and for augmentative control is similar to that of insecticides (1:2-1:5), with much lower development costs. Over the past 120 years, more than 5000 introductions of approximately 2000 non-native control agents have been made against arthropod pests in 196 countries or islands with remarkably few environmental problems. Biological control is a key component of a 'systems approach' to integrated pest management, to counteract insecticide-resistant pests, withdrawal of chemicals and minimize the usage of pesticides. Current studies indicate that genetically modified insect-resistant Bt crops may have no adverse effects on the activity or function of predators or parasitoids used in biological control. The introduction of rational approaches for the environmental risk assessment of non-native control agents is an essential step in the wider application of biological control, but future success is strongly dependent on a greater level of investment in research and development by governments and related organizations that are committed to a reduced reliance on chemical control.     

卷蛾分索赤眼蜂和拟澳洲赤眼蜂对小菜蛾利他素各成分的嗅觉反应

卷蛾分索赤眼蜂Trichogrammatoidea bactrae Nagaraja和拟澳洲赤眼蜂Trichogramma confusum Viggiani是小菜蛾Plutella xylostella (L.)的优势寄生蜂。本研究利用“Y”型管测定了2种赤眼蜂对小菜蛾P. xylostella利他素-卵表和腹部鳞片13种饱和烷烃的嗅觉反应。结果显示: 卷蛾分索赤眼蜂交配雌蜂进入2, 6, 10, 14-四甲基十五烷、正十五烷、正十七烷处理区的百分数分别为80.65%, 68.75%和66.67%, 表明这3种烷烃对卷蛾分索赤眼蜂交配雌蜂有显著的吸引作用, 其他10种饱和烷烃对卷蛾分索赤眼蜂雌蜂无明显作用。拟澳洲赤眼蜂进入2, 6, 10, 14-四甲基十五烷、正三十五烷和正十五烷处理区的数目分别占84.38%, 70%和62.16%, 表明其对拟澳洲赤眼蜂交配雌蜂起着显著的吸引作用, 而另外10种烷烃对拟澳洲赤眼蜂雌蜂无作用。卷蛾分索赤眼蜂和拟澳洲赤眼蜂未交配雄蜂进入13种烷烃处理区和对照区的时间均无显著差异, 表明利他素各组分对2种赤眼蜂未交配雄蜂均无吸引作用。     

Enhancing biological control of basal stem rot disease (<Emphasis Type="Italic">Ganoderma boninense</Emphasis>) in oil palm plantations

Basal Stem Rot (BSR) disease caused by Ganoderma boninense is the most destructive disease in oil palm, especially in Indonesia and Malaysia. The available control measures for BSR disease such as cultural practices and mechanical and chemical treatment have not proved satisfactory due to the fact that Ganoderma has various resting stages such as melanised mycelium, basidiospores and pseudosclerotia. Alternative control measures to overcome the Ganoderma problem are focused on the use of biological control agents and planting resistant material. Present studies conducted at Indonesian Oil Palm Research Institute (IOPRI) are focused on enhancing the use of biological control agents for Ganoderma. These activities include screening biological agents from the oil palm rhizosphere in order to evaluate their effectiveness as biological agents in glasshouse and field trials, testing their antagonistic activities in large scale experiments and eradicating potential disease inoculum with biological agents. Several promising biological agents have been isolated, mainly Trichoderma harzianum, T. viride, Gliocladium viride, Pseudomonas fluorescens, and Bacillus sp. A glasshouse and field trial for Ganoderma control indicated that treatment with T. harzianum and G. viride was superior to Bacillus sp. A large scale trial showed that the disease incidence was lower in a field treated with biological agents than in untreated fields. In a short term programme, research activities at IOPRI are currently focusing on selecting fungi that can completely degrade plant material in order to eradicate inoculum. Digging holes around the palm bole and adding empty fruit bunches have been investigated as ways to stimulate biological agents.     

Deep space and hidden depths: understanding the evolution and ecology of fungal entomopathogens

Entomopathogens are important natural enemies of many insect and mite species and as such have been recognised as providing an important ecosystem service. Indeed, fungal entomopathogens have been widely investigated as biological control agents of pest insects in attempts to improve the sustainability of crop protection. However, even though our understanding of the ecology of fungal entomopathogens has vastly increased since the early 1800s, we still require in-depth ecological research that can expand our scientific horizons in a manner that facilitates widespread adoption of these organisms as efficient biological control agents. Fungal entomopathogens have evolved some intricate interactions with arthropods, plants and other microorganisms. The full importance and complexity of these relationships is only just becoming apparent. It is important to shift our thinking from conventional biological control, to an understanding of an as yet unknown “deep space”. The use of molecular techniques and phylogenetic analyses have helped us move in this direction, and have provided important insights on fungal relationships. Nevertheless, new techniques such as the PhyloChip and pyrosequencing might help us see beyond the familiar fields, into areas that could help us forge a new understanding of the ecology of fungal entomopathogens.     

Behavioral Aspects of Rodent Population Biology

Five approaches to the study of behavior as a factor in thepopulation biology of rodents are outlined. These approachesare: (1) genetics, (2) physiology, (3) chronobiology,(4) behavioralecology and sociobiology, and (5) the use of intra- and inter-specificcomparisons. For each approach selected examples from the recentliterature, from this symposium and from my own work are usedto illustrate the new directions that are emerging for analyzingbehavior as a factor affecting natality, mortality and emigration/immigrationin rodents. Areas where additional investigations are neededare noted including some questions to be tested by future experiments.A variety of new techniques that have been developed or areinnovative applications of existing techniques are incorporatedinto the examples. Most of the material presented concerns fourgenera of rodents, Microtus, Mus, Peromyscus, and Rattus. Thefollowing major conclusions emerge from an overview of theseapproaches: Most recent research on behavior as a factor inrodent population biology has been concerned primarily withnatality. Few investigators have dealt with mortality and onlya limited number have explored emigration/immigration. Fieldand laboratory studies on behavioral aspects of rodent populationbiology have become more integrated than they were several decadesago. Both proximate and ultimate questions about behavior andpopulation dynamics are now being tested by both laboratoryand field methods. In contrast to some earlier approaches thatoften viewed population control as involving a single factor,most emerging conceptual frameworks have, as a major assumption,that population regulation is a multi-factorial process includingmany behavioral components.     

The role of public policy in biological control: Some global trends

The past decade has been a rapid development in the view that contemporary agricultural practices should meet the needs of the present without compromising the ability of future generations. This philosophy has broadened the priorities for research and development in primary production systems. Now there is reduced emphasis on efficiency and productivity, and an increased concern for ecological sustainability. This has had an impact on policies relating to biological control technologies and associated policies have been developed to enhance the uptake of biopesticides. At the same time international agreements on climate change, biodiversity and global trading have potential influences on the use of biological control agents and biological technologies. In this review some of these trends in public policy are highlighted as well as the likely effect they may have in the adoption, implementation and ongoing development of biological control technologies.     

Strain improvement of fungal insecticides for controlling insect pests and vector-borne diseases

Insect pathogenic fungi play an important natural role in controlling insect pests. However, few have been successfully commercialized due to low virulence and sensitivity to abiotic stresses that produce inconsistent results in field applications. These limitations are inherent in most naturally occurring biological control agents but development of recombinant DNA techniques has made it possible to significantly improve the insecticidal efficacy of fungi and their tolerance to adverse conditions, including UV. These advances have been achieved by combining new knowledge derived from basic studies of the molecular biology of these pathogens, technical developments that enable very precise regulation of gene expression, and genes encoding insecticidal proteins from other organisms, particularly spiders and scorpions. Recent coverage of genomes is helping determine the identity, origin, and evolution of traits needed for diverse lifestyles and host switching. In future, such knowledge combined with the precision and malleability of molecular techniques will allow design of multiple pathogens with different strategies and host ranges to be used for different ecosystems, and that will avoid the possibility of the host developing resistance. With increasing public concern over the continued use of synthetic chemical insecticides, these new types of biological insecticides offer a range of environmental-friendly options for cost-effective control of insect pests.     

Current strategies and perspectives in detection and control of basal stem rot of oil palm

The rapid expansion of oil palm (OP) has led to its emergence as a commodity of strategic global importance. Palm oil is used extensively in food and as a precursor for biodiesel. The oil generates export earnings and bolsters the economy of many countries, particularly Indonesia and Malaysia. However, oil palms are prone to basal stem rot (BSR) caused by Ganoderma boninense which is the most threatening disease of OP. The current control measures for BSR management including cultural practices, mechanical and chemical treatment have not proved satisfactory. Alternative control measures to overcome the G. boninense problem are focused on the use of biological control agents and many potential bioagents were identified with little proven practical application. Planting OP varieties resistant to G. boninense could provide the ideal long-term solution to basal stem rot. The total resistance of palms to G. boninense has not yet been reported, and few examples of partial resistances have been observed. Importantly, basidiospores are now recognized as the method by which the disease is spread, and control methods require to be revaluated because of this phenomenon. Many methods developed to prevent the spread of the disease effectively are only tested at nursery levels and are only reported in national journals inhibiting the development of useful techniques globally. The initial procedures employed by the fungus to infect the OP require consideration in terms of the physiology of the growth of the fungus and its possible control. This review assesses critically the progress that has been made in BSR development and management in OP.     

Evolutionary and Functional Aspects of Pituitary Gonadotropins in the Green Turtle, Chelonia Mydas

Information on the pituitary gonadotropins in Chelonia mydasrepresents some of the most complete data available for anyreptile and thus provides an important basis for evaluatingevolutionary processes in tetrapod endocrine physiology. Thetwo gonadotropins isolated from Chelonia pituitary glands showclear chemical and immunological homologies to mammalian follicle-stimulatinghormone (FSH) and luteinizing hormone (LH). However, receptorstudies and biological tests indicate that the functions ofthese hormones may be different in turtles and mammals. In particular,Chelonia LH shows an unusual ability to interact with FSH receptorsites and to stimulate physiological functions normally attributedto FSH. Results with Chelonia LH demonstrate that errors mayarise from using mammalian hormones to investigate reproductionin turtles. Measurements of endogenous gonadotropin levels inthe plasma of breeding and nesting Chelonia provide a differentperspective of the potential roles of the FSH and LH from thatobtained in physiological tests. In particular, FSH and LH secretionare markedly dissociated during the nesting cycle; FSH has onlya transient peak during oviposition, whereas LH, along withprogesterone, displays a pronounced "ovulatory" surge in theday following nesting. Preliminary studies with synthetic gonadotropicreleasing factors in Chelonia suggest that these may be usefulin inducing reproductive changes.     

The tetrazolium-formazan system: design and histochemistry.

Our increasing knowledge about the chemistry and the correlations between chemical structure and histochemical properties of the tetrazolium/formazan system is resulting in: a better understanding of existing histochemical tetrazolium techniques; the selection of optimal tetrazolium salts for qualified use in histochemistry, cytochemistry and biochemistry; both qualitative and quantitative improvements in histochemical techniques for purposes demonstrating the activities of various dehydrogenating enzymes; an extended insight into the "state" of the tested biological object by means of tetrazolium indicators with special properties; and the combination of histochemical enzyme determination with further morphological techniques. This article has attempted to illustrate the progress in the use of the tetrazolium/formazan-system for histochemical purposes.     

Reproductive Endocrinology of Fishes

While evidence is currently lacking for the agnatha and elasmobranchs,the release of pituitary gonadotropin by the teleost pituitaryappears to be under stimulatory control by the hypothalamus. Gonadotropin has to date only been purified from teleost pituitaryglands. Bioassay and biochemical data suggest that the teleostpituitary gland elaborates only one gonadotropin; however, thereis some conflicting histological data on this point. Salmongonadotropin has a molecular weight of approximately 29,000at neutral pH and approximately 13,000 at low pH or after treatmentwith 8M urea or 1M propionic acid. Radioimmunossays have recently been developed for carp and salmongonadotropin. Immunological techniques have also been used toidentify pituitary gonadotrops. Pharmacological treatment of fish with methallibure has permittedinhibition of gonadal development while treatment with clomiphenecitrate has stimulated ovulation. The role of corticosteroidsand other steroid hormones in ovulation is still not fully elucidated.It is possible that the control of ovulation may differ betweenspecies. Experiments are described which aim to enhance natural stocksof pink salmon by endocrine manipulation of sexual developmentin the male.