几种杀虫剂对草坪害虫的控制效果

测定了绿僵菌、毒死蜱、辛硫磷等药剂对草坪害虫的控制效果。结果表明绿僵菌、毒死蜱和辛硫磷都是防治草坪地下害虫的有效药剂，毒死蜱和辛硫磷还能有效防治草坪茎叶害虫禾灰翅夜蛾和斜纹夜蛾等。药后45d，绿僵菌对铜绿丽金龟幼虫蛴螬的防效和对地下害虫的总防效分别为91．2％和87．6％。绿僵菌对茎叶害虫的防效较差，药后3、7、10d时，对禾灰翅夜蛾的防效分别为3．7％、9．2％和18．9％；对茎叶害虫的总防效在12．2％以下。辛硫磷和毒死蜱药后3d对禾灰翅夜蛾的防效分别是93．7％和97．6％；对茎叶害虫的总防效分别是92．0％和93．6％。当高效氯氰菊酯分别和辛硫磷、毒死蜱混用防治斜纹夜蛾时，防效更高、速效性更好。     

真菌类农药开发成果

中国开展真菌制剂的研究开发已有30多年的历史，其中主要以研究白僵菌制剂为主，每年应用自僵菌防治松毛虫和玉米螟等的面积达了70万公顷以上。木霉菌已开发成功，取得农药登记注册，用于防治蔬菜灰霉病具有较理想的效果和应用前景。目前处于小试和中试阶段的真菌制剂还有绿僵菌、淡紫拟青霉、虫霉和蜡蚧轮枝菌等。     

杀蝗绿僵菌与植物源农药混用对亚洲小车蝗的杀虫效果

在室内和田间分别测定了植物源农药印楝素和苦参碱与绿僵菌Metarhizium anisopliae混用对亚洲小车蝗Oedaleus asiaticus的协同致死作用.室内测定结果表明:印楝素和苦参碱与绿僵菌混合施用时对亚洲小车蝗的防效显著增强,表现明显的协同作用.印楝素和绿僵菌混用与单独施用绿僵菌相比对亚洲小车蝗的LT50缩短了约3.17 d,苦参碱和绿僵菌混用与单独施用绿僵菌相比对亚洲小车蝗的LT50缩短了约1.81 d;田间小区试验表明:印楝素和苦参碱与绿僵菌混合施用的防效都达到90%以上.差异显著性分析表明混合施用和单独施用绿僵菌的差异显著.因此,植物源农药与绿僵菌可以结合用于防治亚洲小车蝗.     

来自昆虫病原真菌伤寒拟青霉的新颖四酰胺酸和吡啶酮生物碱--密里特酮B、C和D

昆虫病原真菌是一类在生态学上具有高度专一性的微生物。已知的 70 0种昆虫病原真菌分别属于半知菌、子囊菌、接合菌、卵菌、担子菌、壶菌和毛菌等纲。它们存在于除了极地以外的各个气候带 ,并对它们所处的环境高度适应。例如属于半知菌的绿僵菌和白僵菌从 1 9世纪末就被用作杀虫剂了。广泛存在于热带、亚热带地区的虫草属 (子囊菌、麦角菌 )真菌 ,其寄生于许多昆虫的虫菌合体期在东南亚长期被使用 ,并发现其具有医药作用。人们只对少数昆虫病原真菌研究了其次生代谢物 ,已报道的有半知菌色素如卵孢菌素、纤细白僵灵(tenellin)、白僵宁 (bas…     

金龟子绿僵菌-四氯虫酰胺混配对小白菜黄条跳甲的毒力及田间药效评价

为筛选适用于防治小白菜黄条跳甲的有效药剂，采用浸虫法测定了金龟子绿僵菌与四氯虫酰胺及其不同配比组合对小白菜黄条跳甲的联合毒力，并测定了最佳配比药剂对小白菜黄条跳甲的田间药效。金龟子绿僵菌和四氯虫酰胺混配比为6∶1时，对小白菜黄条跳甲的增效作用最为明显，其共毒系数为470.80。田间药效试验结果显示，7%金龟子绿僵菌·四氯虫酰胺悬浮剂对小白菜黄条跳甲防效较好，使用剂量为25～35 m L/667 m²时，防治成虫与幼虫效果均可达到80%以上。试验期间，试验药剂各处理对小白菜生长无影响无药害，对其他非靶标生物无不良影响。7%金龟子绿僵菌·四氯虫酰胺悬浮剂可作为防控小白菜黄条跳甲的有效药剂。     

金龟子绿僵菌固态发酵环境变量优化研究

研究了培养温度、光照、培养基初始pH等环境因素对金龟子绿僵菌生长及产孢量的影响,总结了发酵过程培养物含水量的变化及其与产孢量的关系。经过优化,得到金龟子绿僵菌产孢的最佳培养条件为:培养温度27℃、避光培养、培养基初始pH6.0,培养6d孢子产量可达1.21×1010孢子/g干培养基。培养基的湿含量控制应为发酵前期高湿、后期低湿。     

腐败菌素研究进展——腐败菌素化合物的化学合成、生物合成、生物代谢降解和生物活性

自1961年首次从金龟子绿僵菌即卵形孢霉(Oospora destructor)的代谢产物中分离得到腐败菌素A(Destruxin A)和腐败菌素B(destruxin B)以来，对该系统化合物的研究报道不断涌现。腐败菌素(destruxin)因代谢产生菌Oospora destructor而得名为destruxin。尽管后来该菌被重新命名为金龟子绿僵菌(Metarrhizium anisopliae)，但由于沿袭传统的命名名称，该系统化合物的名称得以保留。     

3种绿僵菌对小翅雏蝗的室内致病力测定

确定绿僵菌对小翅雏蝗的室内致病力,为在田间利用绿僵菌防治小翅雏蝗奠定基础.在室内用药液浸虫法测定了3株绿僵菌对小翅雏蝗的致病力.绿僵菌的致病力强弱与菌株种类和接种剂量有密切关系.菌株对小翅雏蝗的致病力由强到弱顺序为IPPCAAS2029＞M09＞M1245.菌株IPPCAAS2029的孢子浓度在1.94x10 9个/mL情况下,对蝗蝻的LT50为4.26 d.绿僵菌对小翅雏蝗种群显著的毒力作用,在防治蝗虫上有很好的应用前景.     

二十一世纪的微生物杀虫剂及其防治

本文讨论过去和现在的微生物防治和微生物杀虫剂以及二十一世纪日本应用微生物杀虫剂进行仿生害物防治的建议和展望。微生物杀虫剂的历史 Agostino Bassi在1835年首次报道由微生物(一种真菌)引起的传染性病害-僵病(muscardino)。Bassi用实验证实该寄主菌在家蚕(Bombyx mori)幼虫活体内能生长发育,该传染病原能采用接种或接触或污染饲料的方法传布发病,某些化学品和物理处理可杀     

绿僵菌防治铜绿丽金龟蛴螬药效试验

通过金龟子绿僵菌M105–32对铜绿丽金龟子幼虫进行的室内毒力及田间应用试验,结果表明,绿僵菌对蛴螬有较强的致病性,适宜在土壤中施用,如果在土壤中施入足够绿僵菌剂量,可以有效控制蛴螬的为害。     

Determination of the minimum number of spacer particles ensuring non-contact between host particles — A new approach by numerical modelling

The minimal number of spacer particles needed to ensure non-contact of host particles is of special interest with respect to the development of powders aiming at decreasing the interparticle forces between the host particles in order to ensure good flowability, dosing and fluidisation. As there is no detailed analytical approach available in literature of checking two host particles with respect to contact, even for the most simple system of monodisperse, spherical host particles covered by monodisperse, spherical guest particles, the present study is intended to give a sound mathematical solution to the question how many guest particles are minimally needed in order to ensure non-contact of host particles. This solution has been a numerical one up to now.In order to calculate this minimal coverage level a new computation model has been created and implemented in MATLAB®. The program performs three basic steps. The positioning of guest particles represented by imaginary point charges is carried out using Coulomb's Law leading to the uniform distribution of the guest particles on the host particle. In the second step circumcircles of every three guest particles are computed in order to find out the site where the host particles are most likely to get into contact. In the final step two host particles are checked for contact at this site. By multiple executions of these steps with modified numbers of guest particles, the minimal coverage is determined.     

Chemical association in symbiosis sterol donors in planthoppers

The role of intracellular symbionts contributing to their host has been investigated in the planthoppers,Nilaparvata lugens Stal andLaodelphax striatellus Fallen. We have found that the isolated yeastlike symbionts, identified as a member of the genusCandida, from the host's egg produce ergosterol when cultured. A comparative study of sterols in the cultured symbionts, the host insects, aposymbiotic host insects, and dietary plants demonstrated that ergosterol produced in the symbiotes is provided to the host insects and possibly transformed in the host insects into cholesterol via 24-methylenecholesterol. The conversion of injected 24-methylenecholesterol-d₃ into cholesterol has been shown in the brown planthopper (N. lugens).     

The haustorium and the chemistry of host recognition in parasitic angiosperms

Two parasitic angiosperms,Agalinis purpurea (Scrophulariaceae) andStriga asiatica (Scrophulariaceae), are compared as to the chemical recognition events involved in host selection.Agalinis is a hemiparasite which can mature to seed-set without a host, whereasStriga is a holoparasite and survives for only a very limited time without a host. Both parasites, however, attach to a host through a specialized organ known as the haustorium and regulate the development of this organ through the recognition of chemical factors from host plants. We now describe the discovery of 2,6-dimethoxy-p-benzoquinone (2,6-DMBQ) as an haustoria-inducing principle fromSorghum root extracts. Our investigation of this compound has led us to suggest that one level of host recognition in these parasitic plants is mediated through their enzymatic digestion of the host root surface. Degradation of surface components liberates quinonoid compounds, such as 2,6-DMBQ, which in turn trigger haustorial development.     

修饰β-环糊精与非瑟酮包合物的制备及其抗氧化活性研究

水溶液法合成β-CD顺丁烯二酸单酯,再与氯化亚砜和N,N′-二(3-氨丙基)乙二胺反应,从而制得N,N′-二(3-氨丙基)乙二胺修饰β-CD(主体)。通过饱和水溶液法制备主体与非瑟酮(客体)的包合物。采用UV、IR等表征并测定主体与客体的结合稳定常数,通过DPPH法测定包合物的抗氧化活性。结果表明,主体与客体的结合稳定常数K_S=2.1308×10⁵,包合物对DPPH自由基具有较好的抗氧化活性。     

Survey of a Salivary Effector in Caterpillars: Glucose Oxidase Variation and Correlation with Host Range

Salivary glucose oxidase (GOX) has been reported in a few insect species where it plays a role in protection against infectious disease. Our recent research has focused on the role of this salivary enzyme in the noctuid Helicoverpa zea, where it functions as an effector to suppress the induced defenses of the host plant Nicotiana tabacum. In this study, we examined the labial gland GOX activities in 23 families of Lepidoptera (85 species) and two families of plant-feeding Hymenoptera (three species). We analyzed the relationship between host breadth and GOX activities, and we found a significant relationship, where highly polyphagous species were more likely to possess relatively high levels of GOX compared to species with more limited host range. We also examined the effect of diet on GOX activity and found that the host plant had a significant effect on enzyme activity. The significance of these findings is discussed in relation to caterpillar host breadth.     

Antibacterial and Anti-biofilm Activity of the Human Breast Milk Glycoprotein Lactoferrin against Group B Streptococcus

Group B Streptococcus (GBS) is an encapsulated Gram-positive human pathogen that causes invasive infections in pregnant hosts and neonates, as well as immunocompromised individuals. Colonization of the human host requires the ability to adhere to mucosal surfaces and circumnavigate the nutritional challenges and antimicrobial defenses associated with the innate immune response. Biofilm formation is a critical process to facilitate GBS survival and establishment of a replicative niche in the vertebrate host. Previous work has shown that the host responds to GBS infection by producing the innate antimicrobial glycoprotein lactoferrin, which has been implicated in repressing bacterial growth and biofilm formation. Additionally, lactoferrin is highly abundant in human breast milk and could serve a protective role against invasive microbial pathogens. This study demonstrates that human breast milk lactoferrin has antimicrobial and anti-biofilm activity against GBS and inhibits its adherence to human gestational membranes. Together, these results indicate that human milk lactoferrin could be used as a prebiotic chemotherapeutic strategy to limit the impact of bacterial adherence and biofilm formation on GBS-associated disease outcomes.     

Host nutritive quality and host plant choice in two grass miners: primary roles for primary compounds?

The relationship between host plant choice and plant nutritional quality was investigated in two oligophagous grass miners Chromatomyia milii and C. nigra (Diptera, Agromyzidae). We tested whether host choice is determined by chemically mediated host suitability for offspring performance and/or adult performance. A second goal was to relate the observed variation among the different fitness parameters to quantitative and qualitative variation in foliar food quality. Choice experiments illustrated that both miners discriminated among grass species, and that C. milii has a smaller host range than C. nigra, as observed under natural conditions. Oviposition preference was correlated with adult feeding preference and related adult performance (longevity and fecundity) for both miners. Offspring performance measures (survival and pupal size) of at least C. nigra were more weakly related to host preference. Nearly all variation in adult performance of both miners was explained by foliar protein content, which had a positive effect on adult longevity and fecundity. Pupal size of both miners was positively related to foliar water and amino acid content and negatively related to lignin content. No clear relationship between host chemistry and offspring survival was observed. These observations show that fitness parameters are differentially related to host chemistry. Secondly, they suggest that chemically mediated host suitability for adult performance is an important determinant of host choice in this species. Finally, the results suggest a primary role for foliar protein content in host choice of the study species in general and in shaping the host range of C. milii in particular.     

The Roles of Ubiquitination in Pathogenesis of Influenza Virus Infection

The ubiquitin system denotes a potent post-translational modification machinery that is capable of activation or deactivation of target proteins through reversible linkage of a single ubiquitin or ubiquitin chains. Ubiquitination regulates major cellular functions such as protein degradation, trafficking and signaling pathways, innate immune response, antiviral defense, and virus replication. The RNA sensor RIG-I ubiquitination is specifically induced by influenza A virus (IAV) to activate type I IFN production. Influenza virus modulates the activity of major antiviral proteins in the host cell to complete its full life cycle. Its structural and non-structural proteins, matrix proteins and the polymerase complex can regulate host immunity and antiviral response. The polymerase PB1-F2 of mutated 1918 IAV, adapts a novel IFN antagonist function by sending the DDX3 into proteasomal degradation. Ultimately the fate of virus is determined by the outcome of interplay between viral components and host antiviral proteins and ubiquitination has a central role in the encounter of virus and its host cell.     

Biochemical Properties and Possible Roles of Ectophosphatase Activities in Fungi

Ectophosphatases are surface membrane-bound proteins whose active sites face the extracellular medium. These enzymes have been reported in several microorganisms including a large number of medically relevant fungal species. An effective technique for identifying ectophosphatases is performing phosphatase activity assays using living intact cells. Biochemical characterization of these activities has shown their differential modulation by classical phosphatase inhibitors, divalent metals and pH range. The physiological roles of ectophosphatases are not well established; however, it has been suggested that these enzymes play important roles in nutrition, proliferation, differentiation, adhesion, virulence and infection. Adhesion to host cells is the first step in establishing a fungal infection and ectophosphatases may be one of the first parasite proteins that come into contact with the host cells. Several results indicate that ectophosphatase activities increase the capacity of fungi to adhere to the host cells. In this context, the present review provides an overview of recent discoveries related to the occurrence and possible roles of ectophosphatase activities in fungal cells.