Science.gov

Sample records for insect pathogen metarhizium

  1. Conidia of the insect pathogenic fungus, Metarhizium anisopliae, fail to adhere to mosquito larval cuticle

    PubMed Central

    Greenfield, Bethany P. J.; Lord, Alex M.; Dudley, Ed; Butt, Tariq M.

    2014-01-01

    Adhesion of conidia of the insect pathogenic fungus, Metarhizium anisopliae, to the arthropod host cuticle initially involves hydrophobic forces followed by consolidation facilitated by the action of extracellular enzymes and secretion of mucilage. Gene expression analysis and atomic force microscopy were used to directly quantify recognition and adhesion between single conidia of M. anisopliae and the cuticle of the aquatic larval stage of Aedes aegypti and a representative terrestrial host, Tenebrio molitor. Gene expression data indicated recognition by the pathogen of both hosts; however, the forces for adhesion to the mosquito were approximately five times lower than those observed for Tenebrio. Although weak forces were recorded in response to Aedes, Metarhizium was unable to consolidate firm attachment. An analysis of the cuticular composition revealed an absence of long-chain hydrocarbons in Aedes larvae which are thought to be required for fungal development on host cuticle. This study provides, to our knowledge, the first evidence that Metarhizium does not form firm attachment to Ae. aegypti larvae in situ, therefore preventing the normal route of invasion and pathogenesis from occuring. PMID:26064542

  2. Molecular cloning, characterisation, and expression of a neutral trehalase from the insect pathogenic fungus Metarhizium anisopliae.

    PubMed

    Xia, Yuxian; Gao, Meiying; Clarkson, John; Charnley, A

    2002-06-01

    A neutral trehalase gene (NTH1) was isolated from a lambdaEMBL3 genomic library of the insect pathogenic fungus Metarhizium anisopliae. Sequencing of the gene revealed extensive homology with other fungal neutral trehalases. The NTH1 gene exists as a single copy in the genome. Two STREs exist in the 5'UTR of NTH1, which may mediate transcriptional activation of the NTH1 gene in response to various stresses. The NTH1 gene encodes a protein of 737 amino acids with a calculated M(r) of 83.1kDa. A cyclic adenosine 3',5'-monophosphate-dependent phosphorylation consensus site and a putative calcium binding site were found in the amino-terminal domain of NTH1, consistent with a regulatory enzyme. Expression of the trehalase cDNA was achieved in Saccharomyces cerevisiae. Southern blot analysis of RT-PCR products indicated that the neutral trehalase gene is transcribed in vitro in cell-free haemolymph of the tobacco hornworm Manduca sexta and in vivo in the early stage of infection. PMID:12383437

  3. Community composition and population genetics of insect pathogenic fungi in the genus Metarhizium from soils of a long-term agricultural research system.

    PubMed

    Kepler, Ryan M; Ugine, Todd A; Maul, Jude E; Cavigelli, Michel A; Rehner, Stephen A

    2015-08-01

    Fungi in the genus Metarhizium are insect pathogens able to function in other niches, including soil and plant rhizosphere habitats. In agroecosystems, cropping and tillage practices influence soil fungal communities with unknown effects on the distribution of Metarhizium, whose presence can reduce populations of crop pests. We report results from a selective media survey of Metarhizium in soils sampled from a long-term experimental farming project in the mid-Atlantic region. Field plots under soybean cultivation produced higher numbers of Metarhizium colony-forming units (cfu) than corn or alfalfa. Plots managed organically and via chisel-till harboured higher numbers of Metarhizium cfu than no-till plots. Sequence typing of Metarhizium isolates revealed four species, with M. robertsii and M. brunneum predominating. The M. brunneum population was essentially fixed for a single clone as determined by multilocus microsatellite genotyping. In contrast, M. robertsii was found to contain significant diversity, with the majority of isolates distributed between two principal clades. Evidence for recombination was observed only in the most abundant clade. These findings illuminate multiple levels of Metarhizium diversity that can be used to inform strategies by which soil Metarhizium populations may be manipulated to exert downward pressure on pest insects and promote plant health. PMID:25627647

  4. Community composition and population genetics of insect pathogenic fungi in the genus Metarhizium from soils of a long-term agricultural research system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungi in the genus Metarhizium are facultative pathogens of insects with the capacity to function in other niches, including soil and plant rhizosphere habitats. In agroecosystems, cropping and tillage practices heavily influence soil fungal communities with unknown effects on the distribution of M...

  5. MALDI-TOF mass spectrometry applied to identifying species of insect-pathogenic fungi from the Metarhizium anisopliae complex.

    PubMed

    Lopes, Rogério Biaggioni; Faria, Marcos; Souza, Daniela Aguiar; Bloch, Carlos; Silva, Luciano P; Humber, Richard A

    2014-01-01

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has proven to be a powerful tool for taxonomic resolution of microorganisms. In this proof-of-concept study, we assessed the effectiveness of this technique to track the current gene sequence-based phylogenetic classification of species in the Metarhizium anisopliae complex. Initially the phylogenetic analysis of 5' strains by sequencing of the 59' end of the TEF-1α gene region revealed seven species within M. anisopliae sensu lato and two varieties outside this complex. Because initial studies on MS profiles from different cell types showed that mycelial fragments or conidia produced on nutrient-poor medium may yield too much background noise, all subsequent spectrometric analyses were performed with acidhydrolyzed conidia from 10-12 d old PDA cultures. The initial MALDI-TOF reference library included protein spectral profiles from nine taxonomically distinct, molecularly identified isolates sharing high genetic homology with the ex-type or ex-epitype isolates of these taxa in Metarhizium. A second reference library added one isolate each for M. anisopliae sensu stricto and M. robertsii. The second, larger reference library (including 11 taxa) allowed nearly perfect MALDI-TOF matching of DNA-based species identification for the 40 remaining isolates molecularly recognized as M. anisopliae sensu stricto (n = 19), M. robertsii (n = 6), M. majus (n = 3), M. lepidiotae (n = 1), M. acridum (n = 3), M. flavoviride var. pemphigi (n = 1), plus seven unidentified strains (six of them phylogenetically close to M. anisopliae sensu stricto and one outside the Metarhizium pingshaense-anisopliae-robertsii-brunneum clade). Due to the increasing frequency of phylogenetically (genomically) based taxonomic revisions of fungi, this approach is especially useful for culture collections, because once the protein profiles of Metarhizium isolates are obtained taxonomic updating of MALDI

  6. Spinosad interacts synergistically with the insect pathogen Metarhizium anisopliae against the exotic wireworms Agriotes lineatus and Agriotes obscurus (Coleoptera: Elateridae).

    PubMed

    Ericsson, Jerry D; Kabaluk, J Todd; Goettel, Mark S; Myers, Judith H

    2007-02-01

    We determined that spinosad interacts synergistically with the biocontrol agent Metarhizium anisopliae (Metch) Sorokin to increase the mortality of two wild-collected wireworm species, Agriotes lineatus (L.), and Agriotes obscurus (L.). Bioassays were performed using a M. anisopliae isolate originally acquired from a local wireworm cadaver. M. anisopliae was applied as a soil drench at 3.3 x 10(2) and 10(4) conidia per gram sand, respectively. Soil drenches also were prepared using a commercial formulation of the actinomycete toxins spinosyn-A and spinosyn-D (common name spinosad) at sublethal doses of 1.5, 3, and 6 ppm active ingredient per gram sand. Combined treatments of spinosad and M. anisopliae were synergistic in causing mortality for all spinosad concentrations. Wireworm feeding activity was reduced after exposure to both spinosad and M. anisopliae and was found to be concentration dependent. The high mortality and reduced rate of wireworm feeding suggest that spinosad and M. anisopliae treatment combinations should be tested in the field. PMID:17370806

  7. Interactions of two insect pathogens, Paranosema locustae (Protista: Microsporidia) and Metarhizium acridum (Fungi: Hypocreales), during a mixed infection of Locusta migratoria (Insecta: Orthoptera) nymphs.

    PubMed

    Tokarev, Yuri S; Levchenko, Maxim V; Naumov, Anton M; Senderskiy, Igor V; Lednev, Georgiy R

    2011-02-01

    Locusta migratoria nymphs were fed Paranosema locustae spores and/or surface-treated with Metarhizium acridum 3 (assay 1), 6 (assay 2) or 9 days (assay 3) post microsporidia application (p.m.a.). These three dates corresponded to the key phases of P. locustae development: (a) mass proliferation, (b) transition to sporogenesis and (c) onset of spore maturation, respectively. As a result, locust mortality due to mixed treatment increased slower, equally and faster, as compared to mortality expected from the combination of two pathogens in assays 1-3, respectively. However, a statistically significant difference in survival times was observed only in assay 3, indicating that only at the phase of spore maturation microsporidia drastically increase locust susceptibility to fungal infection. Analysis of perished nymphs showed that fungal treatment 3 days p.m.a. impeded development of microsporidia. Fungal sporulation on locust cadavers was not affected by co-occurring microsporidiosis. PMID:20932843

  8. Flexible metabolism in Metarhizium anisopliae and Beauveria bassiana: role of the glyoxylate cycle during insect pathogenesis.

    PubMed

    Padilla-Guerrero, Israel Enrique; Barelli, Larissa; González-Hernández, Gloria Angélica; Torres-Guzmán, Juan Carlos; Bidochka, Michael J

    2011-01-01

    Insect pathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have an increasing role in the control of agricultural insect pests and vectors of human diseases. Many of the virulence factors are well studied but less is known of the metabolism of these fungi during the course of insect infection or saprobic growth. Here, we assessed enzyme activity and gene expression in the central carbon metabolic pathway, including isocitrate dehydrogenase, aconitase, citrate synthase, malate synthase (MLS) and isocitrate lyase (ICL), with particular attention to the glyoxylate cycle when M. anisopliae and B. bassiana were grown under various conditions. We observed that ICL and MLS, glyoxylate cycle intermediates, were upregulated during growth on 2-carbon compounds (acetate and ethanol) as well as in insect haemolymph. We fused the promoter of the M. anisopliae ICL gene (Ma-icl) to a marker gene (mCherry) and showed that Ma-icl was upregulated when M. anisopliae was grown in the presence of acetate. Furthermore, Ma-icl was upregulated when fungi were engulfed by insect haemocytes as well as during appressorium formation. Addition of the ICL inhibitor 3-nitroproprionate delayed conidial germination and inhibited appressorium formation. These results show that these insect pathogenic fungi have a flexible metabolism that includes the glyoxylate cycle as an integral part of germination, pathogenesis and saprobic growth. PMID:20929953

  9. Insect Pathogenic Fungi as Endophytes.

    PubMed

    Moonjely, S; Barelli, L; Bidochka, M J

    2016-01-01

    In this chapter, we explore some of the evolutionary, ecological, molecular genetics, and applied aspects of a subset of insect pathogenic fungi that also have a lifestyle as endophytes and we term endophytic insect pathogenic fungi (EIPF). We focus particularly on Metarhizium spp. and Beauveria bassiana as EIPF. The discussion of the evolution of EIPF challenges a view that these fungi were first and foremost insect pathogens that eventually evolved to colonize plants. Phylogenetic evidence shows that the lineages of EIPF are most closely related to grass endophytes that diverged c. 100MYA. We discuss the relationship between genes involved in "insect pathogenesis" and those involved in "endophytism" and provide examples of genes with potential importance in lifestyle transitions toward insect pathogenicity. That is, some genes for insect pathogenesis may have been coopted from genes involved in endophytic colonization. Other genes may be multifunctional and serve in both lifestyle capacities. The interactions of EIPF with their host plants are discussed in some detail. The genetic basis for rhizospheric competence, plant communication, and nutrient exchange is examined and we highlight, with examples, the benefits of EIPF to plants, and the potential reservoir of secondary metabolites hidden within these beneficial symbioses. PMID:27131324

  10. Agrobacterium-mediated disruption of a nonribosomal peptide synthetase gene in the invertebrate pathogen Metarhizium anisopliae reveals a peptide spore factor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous secondary metabolites have been isolated from the insect pathogenic fungus Metarhizium anisopliae, but the roles of these compounds as virulence factors in disease development are poorly understood. We targeted for disruption by Agrobacterium tumefaciens-mediated transformation a putative n...

  11. Biochemical basis of synergism between pathogenic fungus Metarhizium anisopliae and insecticide chlorantraniliprole in Locusta migratoria (Meyen).

    PubMed

    Jia, Miao; Cao, Guangchun; Li, Yibo; Tu, Xiongbing; Wang, Guangjun; Nong, Xiangqun; Whitman, Douglas W; Zhang, Zehua

    2016-01-01

    We challenged Locusta migratoria (Meyen) grasshoppers with simultaneous doses of both the insecticide chlorantraniliprole and the fungal pathogen, Metarhizium anisopliae. Our results showed synergistic and antagonistic effects on host mortality and enzyme activities. To elucidate the biochemical mechanisms that underlie detoxification and pathogen-immune responses in insects, we monitored the activities of 10 enzymes. After administration of insecticide and fungus, activities of glutathione-S-transferase (GST), general esterases (ESTs) and phenol oxidase (PO) decreased in the insect during the initial time period, whereas those of aryl acylamidase (AA) and chitinase (CHI) increased during the initial period and that of acetylcholinesterase (AChE) increased during a later time period. Activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) decreased at a later time period post treatment. Interestingly, treatment with chlorantraniliprole and M. anisopliae relieved the convulsions that normally accompany M. anisopliae infection. We speculate that locust mortality increased as a result of synergism via a mechanism related to Ca(2+) disruption in the host. Our study illuminates the biochemical mechanisms involved in insect immunity to xenobiotics and pathogens as well as the mechanisms by which these factors disrupt host homeostasis and induce death. We expect this knowledge to lead to more effective pest control. PMID:27328936

  12. Biochemical basis of synergism between pathogenic fungus Metarhizium anisopliae and insecticide chlorantraniliprole in Locusta migratoria (Meyen)

    PubMed Central

    Jia, Miao; Cao, Guangchun; Li, Yibo; Tu, Xiongbing; Wang, Guangjun; Nong, Xiangqun; Whitman, Douglas W.; Zhang, Zehua

    2016-01-01

    We challenged Locusta migratoria (Meyen) grasshoppers with simultaneous doses of both the insecticide chlorantraniliprole and the fungal pathogen, Metarhizium anisopliae. Our results showed synergistic and antagonistic effects on host mortality and enzyme activities. To elucidate the biochemical mechanisms that underlie detoxification and pathogen-immune responses in insects, we monitored the activities of 10 enzymes. After administration of insecticide and fungus, activities of glutathione-S-transferase (GST), general esterases (ESTs) and phenol oxidase (PO) decreased in the insect during the initial time period, whereas those of aryl acylamidase (AA) and chitinase (CHI) increased during the initial period and that of acetylcholinesterase (AChE) increased during a later time period. Activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) decreased at a later time period post treatment. Interestingly, treatment with chlorantraniliprole and M. anisopliae relieved the convulsions that normally accompany M. anisopliae infection. We speculate that locust mortality increased as a result of synergism via a mechanism related to Ca2+ disruption in the host. Our study illuminates the biochemical mechanisms involved in insect immunity to xenobiotics and pathogens as well as the mechanisms by which these factors disrupt host homeostasis and induce death. We expect this knowledge to lead to more effective pest control. PMID:27328936

  13. The MrCYP52 cytochrome P450 monoxygenase gene of Metarhizium robertsii is important for utilizing insect epicuticular hydrocarbons.

    PubMed

    Lin, Liangcai; Fang, Weiguo; Liao, Xinggang; Wang, Fengqing; Wei, Dongzhi; St Leger, Raymond J

    2011-01-01

    Fungal pathogens of plants and insects infect their hosts by direct penetration of the cuticle. Plant and insect cuticles are covered by a hydrocarbon-rich waxy outer layer that represents the first barrier against infection. However, the fungal genes that underlie insect waxy layer degradation have received little attention. Here we characterize the single cytochrome P450 monoxygenase family 52 (MrCYP52) gene of the insect pathogen Metarhizium robertsii, and demonstrate that it encodes an enzyme required for efficient utilization of host hydrocarbons. Expressing a green florescent protein gene under control of the MrCYP52 promoter confirmed that MrCYP52 is up regulated on insect cuticle as well as by artificial media containing decane (C10), extracted cuticle hydrocarbons, and to a lesser extent long chain alkanes. Disrupting MrCYP52 resulted in reduced growth on epicuticular hydrocarbons and delayed developmental processes on insect cuticle, including germination and production of appressoria (infection structures). Extraction of alkanes from cuticle prevented induction of MrCYP52 and reduced growth. Insect bioassays against caterpillars (Galleria mellonella) confirmed that disruption of MrCYP52 significantly reduces virulence. However, MrCYP52 was dispensable for normal germination and appressorial formation in vitro when the fungus was supplied with nitrogenous nutrients. We conclude therefore that MrCYP52 mediates degradation of epicuticular hydrocarbons and these are an important nutrient source, but not a source of chemical signals that trigger infection processes. PMID:22194968

  14. Pathogenicity of entomopathogenic fungus Metarhizium anisopliae (Deuteromycetes) to Ixodes scapularis (Acari: Ixodidae)

    USGS Publications Warehouse

    Zhioua, E.; Browning, M.; Johnson, P.W.; Ginsberg, H.S.; LeBrun, R.A.

    1997-01-01

    The entomopathogenic fungus Metarhizium anisopliae is highly pathogenic to the black-legged tick, Ixodes scapularis. Spore concentrations of 108/ml for engorged larvae and 107/ml for engorged females resulted in 100% tick mortality, 2 wk post-infection. The LC50 value for engorged larvae (concentration to kill 50% of ticks) was 107 spores/ml. Metarhizium anisopliae shows considerable potential as a microbial control agent for the management of Ixodes scapularis.

  15. Fungi with multifunctional lifestyles: endophytic insect pathogenic fungi.

    PubMed

    Barelli, Larissa; Moonjely, Soumya; Behie, Scott W; Bidochka, Michael J

    2016-04-01

    This review examines the symbiotic, evolutionary, proteomic and genetic basis for a group of fungi that occupy a specialized niche as insect pathogens as well as endophytes. We focus primarily on species in the genera Metarhizium and Beauveria, traditionally recognized as insect pathogenic fungi but are also found as plant symbionts. Phylogenetic evidence suggests that these fungi are more closely related to grass endophytes and diverged from that lineage ca. 100 MYA. We explore how the dual life cycles of these fungi as insect pathogens and endophytes are coupled. We discuss the evolution of insect pathogenesis while maintaining an endophytic lifestyle and provide examples of genes that may be involved in the transition toward insect pathogenicity. That is, some genes for insect pathogenesis may have been co-opted from genes involved in endophytic colonization. Other genes may be multifunctional and serve in both lifestyle capacities. We suggest that their evolution as insect pathogens allowed them to effectively barter a specialized nitrogen source (i.e. insects) with host plants for photosynthate. These ubiquitous fungi may play an important role as plant growth promoters and have a potential reservoir of secondary metabolites. PMID:26644135

  16. Variations in UV-B tolerance and germination speed of Metarhizium anisopliae conidia produced on insects and artificial substrates.

    PubMed

    Rangel, Drauzio E N; Braga, Gilberto U L; Flint, Stephan D; Anderson, Anne J; Roberts, Donald W

    2004-01-01

    Solar ultraviolet radiation (UV-A and UV-B) is a major factor in failure of programs using the insect pathogenic fungus Metarhizium anisopliae as a biological control agent. Studies were conducted to determine if growth conditions, viz. artificial (agar media or rice grain) or natural (infected insects) substrates for conidial production affect two traits that directly influence performance of conidia after field application: tolerance to UV-B radiation and conidial germination speed. Conidia of two isolates (ARSEF 23 and ARSEF 2575) of M. anisopliae var. anisopliae produced on potato dextrose agar plus yeast extract (PDAY) or on fungus-killed larvae of two insect species, Galleria mellonella and Zophobas morio, were inactivated by exposure to UV-B radiation. Conidia of both isolates when produced on insect cadavers were significantly more sensitive to UV-B radiation than conidia produced on PDAY. Also, conidia from insect cadavers germinated slower than those from PDAY cultures. A comparison of conidia from artificial substrates showed that conidia produced on Czapek's and Emerson's YpSs agar media or rice grains had higher tolerance to UV-B radiation and germinated faster than conidia raised on PDA and PDAY. Accordingly, the growth substrate and nutritional environment in which conidia are produced influences M. anisopliae conidial UV-B tolerance and speed of germination; and manipulation of these variables could be used to obtain conidia with increased tolerance to UV-B radiation and shorter germination times. PMID:15579316

  17. Ubiquity of insect-derived nitrogen transfer to plants by endophytic insect-pathogenic fungi: an additional branch of the soil nitrogen cycle.

    PubMed

    Behie, Scott W; Bidochka, Michael J

    2014-03-01

    The study of symbiotic nitrogen transfer in soil has largely focused on nitrogen-fixing bacteria. Vascular plants can lose a substantial amount of their nitrogen through insect herbivory. Previously, we showed that plants were able to reacquire nitrogen from insects through a partnership with the endophytic, insect-pathogenic fungus Metarhizium robertsii. That is, the endophytic capability and insect pathogenicity of M. robertsii are coupled so that the fungus acts as a conduit to provide insect-derived nitrogen to plant hosts. Here, we assess the ubiquity of this nitrogen transfer in five Metarhizium species representing those with broad (M. robertsii, M. brunneum, and M. guizhouense) and narrower insect host ranges (M. acridum and M. flavoviride), as well as the insect-pathogenic fungi Beauveria bassiana and Lecanicillium lecanii. Insects were injected with (15)N-labeled nitrogen, and we tracked the incorporation of (15)N into two dicots, haricot bean (Phaseolus vulgaris) and soybean (Glycine max), and two monocots, switchgrass (Panicum virgatum) and wheat (Triticum aestivum), in the presence of these fungi in soil microcosms. All Metarhizium species and B. bassiana but not L. lecanii showed the capacity to transfer nitrogen to plants, although to various degrees. Endophytic association by these fungi increased overall plant productivity. We also showed that in the field, where microbial competition is potentially high, M. robertsii was able to transfer insect-derived nitrogen to plants. Metarhizium spp. and B. bassiana have a worldwide distribution with high soil abundance and may play an important role in the ecological cycling of insect nitrogen back to plant communities. PMID:24334669

  18. Immune responses of locusts to challenge with the pathogenic fungus Metarhizium or high doses of laminarin.

    PubMed

    Mullen, Lisa M; Goldsworthy, Graham J

    2006-04-01

    Two isolates of Metarhizium anisopliae var acridum were tested for their effects on the locust immune system and for comparison with the effects of challenge by injection with laminarin. Isolate IMI 330189 (referred to hereafter as Met 189) is highly pathogenic whether applied topically as conidia or injected as blastospores. However, isolate ARSEF 728 (referred to hereafter as Met 728) is pathogenic only when injected as blastospores, suggesting that the lack of pathogenicity of topically applied conidia from this isolate is due to a failure to penetrate the insect cuticle and gain access to the haemocoel. After topical application of conidia from Met 189, no activation of prophenoloxidase is detected, but injection of blastospores from Met 189 brings about a transient increase in phenoloxidase activity in the haemolymph in both adult locusts and 5th instar nymphs, although this does not prevent fungal-induced mortality. Co-injection of adipokinetic hormone-I (AKH-I) with blastospores prolongs the activation of prophenoloxidase in the haemolymph of adult locusts, and enhances it in nymphs. It is argued that the lack of activation of prophenoloxidase in nymphs shown previously (Mullen, L., Goldsworthy, G., 2003. Changes in lipophorins are related to the activation of phenoloxidase in the haemolymph of Locusta migratoria in response to injection of immunogens. Insect Biochemistry and Molecular Biology 33, 661-670), reflects differences in the sensitivity of the immune system between adults and nymphs rather than distinct qualitative differences, and this is confirmed in this study by the demonstration that doses of laminarin higher than those used previously (>or=100 microg) do activate the prophenoloxidase cascade in 5th instar nymphs. Nodules are formed in locusts of all ages in response to fungal infection or injection of laminarin, although there is wide variation in the number, size and distribution of nodules formed. During the examination of 5th instar nymphs

  19. Clarification of generic and species boundaries for Metarhizium and related fungi through multigene phylogenetics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genus Metarhizium traditionally refers to green-spored asexual insect pathogenic fungi. Through culturing and molecular methods, Metarhizium has been linked to Metacordyceps sexual states. Historically, fungal nomenclature has allowed separate names for the different life-stages of pleomorphic...

  20. Influence of mating and age on susceptibility of the beetle Anoplophora glabripennis to the fungal pathogen Metarhizium brunneum.

    PubMed

    Fisher, Joanna J; Hajek, Ann E

    2016-05-01

    The age and life history of an insect can influence its susceptibility to pathogens. Reproduction can be costly and may trade off with immunity while it is generally assumed that immunity will decrease with increasing age through a process called immunosenescence. Fungal pathogens are used as biological control agents for a variety of insect pests, and Metarhizium brunneum is being developed to control the Asian longhorned beetle (Anoplophora glabripennis), an invasive wood-borer. Because adult female A. glabripennis take 1-2weeks to mature after eclosion and both sexes can be long-lived, we investigated how age and mating status would influence susceptibility of A. glabripennis to M. brunneum. Young (6.5day-old) unmated, mature (27-33day-old) mated and unmated, and old (57-71day-old) unmated and mated adults were inoculated with a lethal dose of M. brunneum. The presence of M. brunneum in the hemolymph was quantified and beetle mortality was monitored daily. There was a cost to reproduction for mated mature male and female beetles which died a median of 1.6-1.9days earlier than unmated beetles, while there was no effect of mating on susceptibility for old beetles. We found no evidence for immunosenescence in old beetles, as they did not die faster than young or mature beetles. Young unmated males however were more susceptible than mature or old unmated males, while there was no effect of age on susceptibility of unmated females. PMID:27103165

  1. Pathogenicity of Metarhizium anisopliae (Deuteromycetes) and permethrin to Ixodes scapularis (Acari: Ixodidae) nymphs

    USGS Publications Warehouse

    Hornbostel, V.L.; Zhioua, E.; Benjamin, M.A.; Ginsberg, H.S.; Ostfeld, R.S.

    2005-01-01

    Effectiveness of the entomopathogenic fungus Metarhizium anisopliae, for controlling nymphal Ixodes scapularis, was tested in laboratory and field trials. In the laboratory, M. anisopliae (Metschnikoff) Sorokin strain ESC1 was moderately pathogenic, with an LC50 of 107 spores/ml and induced 70% mortality at 109 spores/ml. In a field study, however, 109 spores/ml M. anisopliae did not effectively control questing I. scapularis nymphs, and significant differences were not detected in pre- and post-treatment densities. For nymphs collected and returned to the laboratory for observation, mortality was low in treatment groups, ranging from 20 to 36%. To assess whether a chemical acaricide would synergistically enhance pathogenicity of the fungus, we challenged unfed nymphal I. scapularis with combinations of M. anisopliae and permethrin, a relatively safe pyrethroid acaricide, in two separate bioassays. Significant interactions between M. anisopliae and permethrin were not observed, supporting neither synergism nor antagonism.

  2. Insertion of an Esterase Gene into a Specific Locust Pathogen (Metarhizium acridum) Enables It to Infect Caterpillars

    PubMed Central

    Wang, Sibao; Fang, Weiguo; Wang, Chengshu; St. Leger, Raymond J.

    2011-01-01

    An enduring theme in pathogenic microbiology is poor understanding of the mechanisms of host specificity. Metarhizium is a cosmopolitan genus of invertebrate pathogens that contains generalist species with broad host ranges such as M. robertsii (formerly known as M. anisopliae var. anisopliae) as well as specialists such as the acridid-specific grasshopper pathogen M. acridum. During growth on caterpillar (Manduca sexta) cuticle, M. robertsii up-regulates a gene (Mest1) that is absent in M. acridum and most other fungi. Disrupting M. robertsii Mest1 reduced virulence and overexpression increased virulence to caterpillars (Galleria mellonella and M. sexta), while virulence to grasshoppers (Melanoplus femurrubrum) was unaffected. When Mest1 was transferred to M. acridum under control of its native M. robertsii promoter, the transformants killed and colonized caterpillars in a similar fashion to M. robertsii. MEST1 localized exclusively to lipid droplets in M. robertsii conidia and infection structures was up-regulated during nutrient deprivation and had esterase activity against lipids with short chain fatty acids. The mobilization of stored lipids was delayed in the Mest1 disruptant mutant. Overall, our results suggest that expression of Mest1 allows rapid hydrolysis of stored lipids, and promotes germination and infection structure formation by M. robertsii during nutrient deprivation and invasion, while Mest1 expression in M. acridum broadens its host range by bypassing the regulatory signals found on natural hosts that trigger the mobilization of endogenous nutrient reserves. This study suggests that speciation in an insect pathogen could potentially be driven by host shifts resulting from changes in a single gene. PMID:21731492

  3. Assessing the optimal virulence of malaria‐targeting mosquito pathogens: a mathematical study of engineered Metarhizium anisopliae

    PubMed Central

    2014-01-01

    Background Metarhizium anisopliae is a naturally occurring fungal pathogen of mosquitoes. Recently, Metarhizium has been engineered to act against malaria by directly killing the disease agent within mosquito vectors and also effectively blocking onward transmission. It has been proposed that efforts should be made to minimize the virulence of the fungal pathogen, in order to slow the development of resistant mosquitoes following an actual deployment. Results Two mathematical models were developed and analysed to examine the efficacy of the fungal pathogen. It was found that, in many plausible scenarios, the best effects are achieved with a reduced or minimal pathogen virulence, even if the likelihood of resistance to the fungus is negligible. The results for both models depend on the interplay between two main effects: the ability of the fungus to reduce the mosquito population, and the ability of fungus‐infected mosquitoes to compete for resources with non‐fungus‐infected mosquitoes. Conclusions The results indicate that there is no obvious choice of virulence for engineered Metarhizium or similar pathogens, and that all available information regarding the population ecology of the combined mosquito‐fungus system should be carefully considered. The models provide a basic framework for examination of anti‐malarial mosquito pathogens that should be extended and improved as new laboratory and field data become available. PMID:24397503

  4. Metarhizium robertsii Produces an Extracellular Invertase (MrINV) That Plays a Pivotal Role in Rhizospheric Interactions and Root Colonization

    PubMed Central

    Liao, Xinggang; Fang, Weiguo; Lin, Liangcai; Lu, Hsiao-Ling; Leger, Raymond J. St.

    2013-01-01

    As well as killing pest insects, the rhizosphere competent insect-pathogenic fungus Metarhizium robertsii also boosts plant growth by providing nitrogenous nutrients and increasing resistance to plant pathogens. Plant roots secrete abundant nutrients but little is known about their utilization by Metarhizium spp. and the mechanistic basis of Metarhizium-plant associations. We report here that M. robertsii produces an extracellular invertase (MrInv) on plant roots. Deletion of MrInv (⊿MrInv) reduced M. robertsii growth on sucrose and rhizospheric exudates but increased colonization of Panicum virgatum and Arabidopsis thaliana roots. This could be accounted for by a reduction in carbon catabolite repression in ⊿MrInv increasing production of plant cell wall-degrading depolymerases. A non-rhizosphere competent scarab beetle specialist Metarhizium majus lacks invertase which suggests that rhizospheric competence may be related to the sugar metabolism of different Metarhizium species. PMID:24205119

  5. Hunting for insect pathogens: A genomics approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emerging methods within the field of genomics have increased the number of insect pathogens being discovered and characterized each year. These pathogens provide a rich resource for biological control agents, gene expression systems, and other molecular tools. Using Metagenomics, and gene expression...

  6. Insect pathogens: molecular approaches and techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book serves as a primer for molecular techniques in insect pathology and is tailored for a wide scientific audience. Contributing authors are internationally recognized experts. The book comprises four sections: 1) pathogen identification and diagnostics, 2) pathogen population genetics and p...

  7. Comparative studies of Metarhizium anisopliae and Tolypocladium cylindrosporum as pathogens of mosquito larvae.

    PubMed

    Riba, G; Keita, A; Soares, G G; Ferron, P

    1986-12-01

    Mosquito fungal pathogens, Metarhizium anisopliae and Tolypocladium cylindrosporum, were compared with regard to virulence against the larvae of Aedes aegypti, Anopheles stephensi and Culex pipiens. Culex pipiens larvae were much more susceptible to M. anisopliae conidia than An. stephensi or Ae. aegypti. But Ae. aegypti and Cx. pipiens larvae were equally susceptible to T. cylindrosporum propagules which weakly attack An. stephensi. Using a high concentration conidial suspension (10(7) sp/ml) of M. anisopliae no. 139, Ae. aegypti larvae were killed immediately within 1.1 days, before intrahemocoelian invasion; but at lower concentrations (10(6) and 10(5) sp/ml), typical mycosis occurred. However, T. cylindrosporum no. 3 blastospores were much more pathogenic to Ae. aegypti larvae than conidia. Conidial suspension of 10(7) spores/ml killed 68% fourth-instar larvae, relative to the 96% invaded by blastospores under the same conditions. Presoaked conidia virulence appeared still intermediate between conidia and blastospores. At low temperatures, 15 degrees C, virulence of M. anisopliae highly decreased, while at the same temperature, T. cylindrosporum blastospores were still virulent. PMID:2906985

  8. Soil Persistence of Metarhizium anisopliae Applied to Manage Sugarbeet Root Maggot in a Cover Crop Microenvironment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sugarbeet root maggot, Tetanops myopaeformis (Röder), is a major insect pest of sugarbeet, Beta vulgaris L., in North Dakota, Minnesota, and Idaho. Three field trials using the insect pathogen Metarhizium anisopliae (Metch.) Sorok. ATCC 62176 in conjunction with cover crops were conducted in 200...

  9. Production of microsclerotia of the fungal entomopathogen Metarhizium anisopliae and their potential for use as a biocontrol agent for soil-inhabiting insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microsclerotia (MS), overwintering structures produced by many plant pathogenic fungi, have not been described for Metarhizium anisopliae. Three strains of M. anisopliae – F52, TM109, and MA1200 – formed MS in shake flask cultures using media with varying carbon concentrations and carbon-to-nitroge...

  10. Agrobacterium-Mediated Disruption of a Nonribosomal Peptide Synthetase Gene in the Invertebrate Pathogen Metarhizium anisopliae Reveals a Peptide Spore Factor▿ †

    PubMed Central

    Moon, Yong-Sun; Donzelli, Bruno G. G.; Krasnoff, Stuart B.; McLane, Heather; Griggs, Mike H.; Cooke, Peter; Vandenberg, John D.; Gibson, Donna M.; Churchill, Alice C. L.

    2008-01-01

    Numerous secondary metabolites have been isolated from the insect pathogenic fungus Metarhizium anisopliae, but the roles of these compounds as virulence factors in disease development are poorly understood. We targeted for disruption by Agrobacterium tumefaciens-mediated transformation a putative nonribosomal peptide synthetase (NPS) gene, MaNPS1. Four of six gene disruption mutants identified were examined further. Chemical analyses showed the presence of serinocyclins, cyclic heptapeptides, in the extracts of conidia of control strains, whereas the compounds were undetectable in ΔManps1 mutants treated identically or in other developmental stages, suggesting that MaNPS1 encodes a serinocyclin synthetase. Production of the cyclic depsipeptide destruxins, M. anisopliae metabolites also predicted to be synthesized by an NPS, was similar in ΔManps1 mutant and control strains, indicating that MaNPS1 does not contribute to destruxin biosynthesis. Surprisingly, a MaNPS1 fragment detected DNA polymorphisms that correlated with relative destruxin levels produced in vitro, and MaNPS1 was expressed concurrently with in vitro destruxin production. ΔManps1 mutants exhibited in vitro development and responses to external stresses comparable to control strains. No detectable differences in pathogenicity of the ΔManps1 mutants were observed in bioassays against beet armyworm and Colorado potato beetle in comparison to control strains. This is the first report of targeted disruption of a secondary metabolite gene in M. anisopliae, which revealed a novel cyclic peptide spore factor. PMID:18502925

  11. The Adh1 gene of the fungus Metarhizium anisopliae is expressed during insect colonization and required for full virulence.

    PubMed

    Callejas-Negrete, Olga Alicia; Torres-Guzmán, Juan Carlos; Padilla-Guerrero, Israel Enrique; Esquivel-Naranjo, Ulises; Padilla-Ballesteros, Maria Fernanda; García-Tapia, Adriana; Schrank, Augusto; Salazar-Solís, Eduardo; Gutiérrez-Corona, Félix; González-Hernández, Gloria Angélica

    2015-03-01

    Zymography of alcohol dehydrogenase (ADH) activity in the entomopathogenic fungus Metarhizium anisopliae grown under various conditions revealed that micro-aerobic growth was associated with increased ADH activity. The major ADH protein, AdhIp, was purified to homogeneity by affinity chromatography and has an estimated molecular weight of 41kDa and an isoelectric point (pI) of 6.4. Peptide mass fingerprint analysis allowed the identification and cloning of the gene that encodes this protein, Adh1, as annotated in the M. anisopliae genome database. AdhIp is related to the medium-chain dehydrogenase/reductase (MDR)/zinc-dependent alcohol dehydrogenase-like family and contains conserved ADH sequence motifs, such as the zinc-containing ADH signature, the FAD/NAD binding domain and amino acid residues that are conserved in most microbial ADHs. Semi-quantitative RT-PCR analysis revealed that Adh1 gene expression occurs at low levels during early Plutella xylostella infection and that the Adh1 gene was primarily expressed at larval death and as mycelia emerge from the insect cuticle before conidiation. Antisense-RNA experiments indicated that NAD(+)-dependent ADH activity was diminished by 20-75% in the transformants, and the transformants that had lower ADH activity showed allyl alcohol resistance, which indicates that reduction in ADH activity also occurs in vivo. Bioassays performed using antisense adh1 transformants, which have lower ADH activity, showed that LC50 values were two to five times higher than the wild-type, indicating that AdhIp is required for full capability of the fungus to penetrate and/or colonize the insect. PMID:25534970

  12. Production of microsclerotia of the fungal entomopathogen Metarhizium anisopliae and their potential for use as a biocontrol agent for soil-inhabiting insects.

    PubMed

    Jackson, Mark A; Jaronski, Stefan T

    2009-08-01

    Microsclerotia (MS), overwintering structures produced by many plant pathogenic fungi, have not been described for Metarhizium anisopliae. Three strains of M. anisopliae--F52, TM109, and MA1200--formed MS in shake flask cultures using media with varying carbon concentrations and carbon-to-nitrogen (C:N) ratios. Under the conditions of this study, all strains produced MS, compact hyphal aggregates that become pigmented with culture age, in addition to more typical blastospores and mycelia. While all strains formed desiccation tolerant MS, highest concentrations (2.7-2.9 x 10(8) L(-1) liquid medium) were produced in rich media with C:N ratios of 30:1 and 50:1 by strain F52. All three strains of M. anisopliae produced similar biomass concentrations when media and growth time were compared. Strain MA1200 produced higher concentrations of blastospores than the other two strains of M. anisopliae with highest blastospore concentrations (1.6 and 4.2 x 10(8) blastospores ml(-1) on days 4 and 8, respectively) in media with the highest carbon and nitrogen concentrations. Microsclerotial preparations of M. anisopliae containing diatomaceous earth survived air-drying (to <5 % moisture) with no significant loss in viability. Rehydration and incubation of air-dried MS granules on water agar plates resulted in hyphal germination and sporogenic germination to produce high concentrations of conidia. Bioassays using soil-incorporated, air-dried MS preparations resulted in significant infection and mortality in larvae of the sugar beet root maggot, Tetanops myopaeformis. This is the first report of the production of sclerotial bodies by M. anisopliae and provides a novel approach for the control of soil-dwelling insects with this entomopathogenic fungus. PMID:19358886

  13. Production of Microsclerotia of Metarhizium anisopliae Using Deep-Tank Liquid Fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The entomopathogenic fungus Metarhizium anisopliae is a pathogen of numerous soil-dwelling insects and has been registered in the United States and other countries as a bioinsecticide. Recent studies using various strains of M. anisopliae showed that small sclerotia (microsclerotia) were produced i...

  14. Clarification of generic and species boundaries for Metarhizium and related fungi through multigene phylogenetics.

    PubMed

    Kepler, Ryan M; Humber, Richard A; Bischoff, Joseph F; Rehner, Stephen A

    2014-01-01

    The genus Metarhizium historically refers to green-spored asexual insect pathogenic fungi. Through culturing and molecular methods, Metarhizium has been linked to Metacordyceps sexual states. Historically fungal nomenclature has allowed separate names for the different life stages of pleomorphic fungi. However, with the move to one name for one fungus regardless of life stage, there is a need to determine which name is correct. For Metarhizium the situation is complicated by the fact that Metacordyceps sexual states are interspersed among additional asexual genera, including Pochonia, Nomuraea and Paecilomyces. Metarhizium has priority as the earliest available name, but delimiting the boundaries of this genus remains problematic. To clarify relationships among these taxa we have obtained representative material for each genus and established a molecular dataset of the protein-coding genes BTUB, RPB1, RPB2 and TEF. The resulting phylogeny supports Metarhizium combining the majority of species recognized in Metacordyceps as well as the green-spored Nomuraea species and those in the more recently described genus Chamaeleomyces. Pochonia is polyphyletic, and we restrict the definition of this genus to those species forming a monophyletic clade with P. chlamydosporia, and the excluded species are transferred to Metapochonia gen. nov. It is our hope that this unified concept of sexual and asexual states in Metarhizium will foster advances in communication and understanding the unique ecologies of the associated species. PMID:24891418

  15. Insect Immunity to Entomopathogenic Fungi.

    PubMed

    Lu, H-L; St Leger, R J

    2016-01-01

    The study of infection and immunity in insects has achieved considerable prominence with the appreciation that their host defense mechanisms share many fundamental characteristics with the innate immune system of vertebrates. Studies on the highly tractable model organism Drosophila in particular have led to a detailed understanding of conserved innate immunity networks, such as Toll. However, most of these studies have used opportunistic human pathogens and may not have revealed specialized immune strategies that have arisen through evolutionary arms races with natural insect pathogens. Fungi are the commonest natural insect pathogens, and in this review, we focus on studies using Metarhizium and Beauveria spp. that have addressed immune system function and pathogen virulence via behavioral avoidance, the use of physical barriers, and the activation of local and systemic immune responses. In particular, we highlight studies on the evolutionary genetics of insect immunity and discuss insect-pathogen coevolution. PMID:27131327

  16. Genome Sequencing and Comparative Transcriptomics of the Model Entomopathogenic Fungi Metarhizium anisopliae and M. acridum

    PubMed Central

    Shang, Yanfang; Duan, Zhibing; Hu, Xiao; Xie, Xue-Qin; Zhou, Gang; Peng, Guoxiong; Luo, Zhibing; Huang, Wei; Wang, Bing; Fang, Weiguo; Wang, Sibao; Zhong, Yi; Ma, Li-Jun; St. Leger, Raymond J.; Zhao, Guo-Ping; Pei, Yan; Feng, Ming-Guang; Xia, Yuxian; Wang, Chengshu

    2011-01-01

    Metarhizium spp. are being used as environmentally friendly alternatives to chemical insecticides, as model systems for studying insect-fungus interactions, and as a resource of genes for biotechnology. We present a comparative analysis of the genome sequences of the broad-spectrum insect pathogen Metarhizium anisopliae and the acridid-specific M. acridum. Whole-genome analyses indicate that the genome structures of these two species are highly syntenic and suggest that the genus Metarhizium evolved from plant endophytes or pathogens. Both M. anisopliae and M. acridum have a strikingly larger proportion of genes encoding secreted proteins than other fungi, while ∼30% of these have no functionally characterized homologs, suggesting hitherto unsuspected interactions between fungal pathogens and insects. The analysis of transposase genes provided evidence of repeat-induced point mutations occurring in M. acridum but not in M. anisopliae. With the help of pathogen-host interaction gene database, ∼16% of Metarhizium genes were identified that are similar to experimentally verified genes involved in pathogenicity in other fungi, particularly plant pathogens. However, relative to M. acridum, M. anisopliae has evolved with many expanded gene families of proteases, chitinases, cytochrome P450s, polyketide synthases, and nonribosomal peptide synthetases for cuticle-degradation, detoxification, and toxin biosynthesis that may facilitate its ability to adapt to heterogenous environments. Transcriptional analysis of both fungi during early infection processes provided further insights into the genes and pathways involved in infectivity and specificity. Of particular note, M. acridum transcribed distinct G-protein coupled receptors on cuticles from locusts (the natural hosts) and cockroaches, whereas M. anisopliae transcribed the same receptor on both hosts. This study will facilitate the identification of virulence genes and the development of improved biocontrol strains

  17. Pathogens and insect herbivores drive rainforest plant diversity and composition.

    PubMed

    Bagchi, Robert; Gallery, Rachel E; Gripenberg, Sofia; Gurr, Sarah J; Narayan, Lakshmi; Addis, Claire E; Freckleton, Robert P; Lewis, Owen T

    2014-02-01

    Tropical forests are important reservoirs of biodiversity, but the processes that maintain this diversity remain poorly understood. The Janzen-Connell hypothesis suggests that specialized natural enemies such as insect herbivores and fungal pathogens maintain high diversity by elevating mortality when plant species occur at high density (negative density dependence; NDD). NDD has been detected widely in tropical forests, but the prediction that NDD caused by insects and pathogens has a community-wide role in maintaining tropical plant diversity remains untested. We show experimentally that changes in plant diversity and species composition are caused by fungal pathogens and insect herbivores. Effective plant species richness increased across the seed-to-seedling transition, corresponding to large changes in species composition. Treating seeds and young seedlings with fungicides significantly reduced the diversity of the seedling assemblage, consistent with the Janzen-Connell hypothesis. Although suppressing insect herbivores using insecticides did not alter species diversity, it greatly increased seedling recruitment and caused a marked shift in seedling species composition. Overall, seedling recruitment was significantly reduced at high conspecific seed densities and this NDD was greatest for the species that were most abundant as seeds. Suppressing fungi reduced the negative effects of density on recruitment, confirming that the diversity-enhancing effect of fungi is mediated by NDD. Our study provides an overall test of the Janzen-Connell hypothesis and demonstrates the crucial role that insects and pathogens have both in structuring tropical plant communities and in maintaining their remarkable diversity. PMID:24463522

  18. Conidial production, persistence and pathogenicity of hydromulch formulations of Metarhizium brunneum F52 microsclerotia under forest conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microsclerotia granules of Metarhizium brunneum Petch strain F52 (Hypocreales: Clavicipitaceae) in hydromulch (water, wheat straw, and tackifier) were sprayed onto bark or wood samples during two spray trials in 2013 and six spray trials in 2014. Microsclerotial granules in hydromulch continued to p...

  19. Insect Pathogenic Bacteria in Integrated Pest Management.

    PubMed

    Ruiu, Luca

    2015-01-01

    The scientific community working in the field of insect pathology is experiencing an increasing academic and industrial interest in the discovery and development of new bioinsecticides as environmentally friendly pest control tools to be integrated, in combination or rotation, with chemicals in pest management programs. In this scientific context, market data report a significant growth of the biopesticide segment. Acquisition of new technologies by multinational Ag-tech companies is the center of the present industrial environment. This trend is in line with the requirements of new regulations on Integrated Pest Management. After a few decades of research on microbial pest management dominated by Bacillus thuringiensis (Bt), novel bacterial species with innovative modes of action are being discovered and developed into new products. Significant cases include the entomopathogenic nematode symbionts Photorhabdus spp. and Xenorhabdus spp., Serratia species, Yersinia entomophaga, Pseudomonas entomophila, and the recently discovered Betaproteobacteria species Burkholderia spp. and Chromobacterium spp. Lastly, Actinobacteria species like Streptomyces spp. and Saccharopolyspora spp. have gained high commercial interest for the production of a variety of metabolites acting as potent insecticides. With the aim to give a timely picture of the cutting-edge advancements in this renewed research field, different representative cases are reported and discussed. PMID:26463190

  20. Insect Pathogenic Bacteria in Integrated Pest Management

    PubMed Central

    Ruiu, Luca

    2015-01-01

    The scientific community working in the field of insect pathology is experiencing an increasing academic and industrial interest in the discovery and development of new bioinsecticides as environmentally friendly pest control tools to be integrated, in combination or rotation, with chemicals in pest management programs. In this scientific context, market data report a significant growth of the biopesticide segment. Acquisition of new technologies by multinational Ag-tech companies is the center of the present industrial environment. This trend is in line with the requirements of new regulations on Integrated Pest Management. After a few decades of research on microbial pest management dominated by Bacillus thuringiensis (Bt), novel bacterial species with innovative modes of action are being discovered and developed into new products. Significant cases include the entomopathogenic nematode symbionts Photorhabdus spp. and Xenorhabdus spp., Serratia species, Yersinia entomophaga, Pseudomonas entomophila, and the recently discovered Betaproteobacteria species Burkholderia spp. and Chromobacterium spp. Lastly, Actinobacteria species like Streptomyces spp. and Saccharopolyspora spp. have gained high commercial interest for the production of a variety of metabolites acting as potent insecticides. With the aim to give a timely picture of the cutting-edge advancements in this renewed research field, different representative cases are reported and discussed. PMID:26463190

  1. Responses of temperate forest productivity to insect and pathogen disturbances

    NASA Astrophysics Data System (ADS)

    Flower, C. E.; Gonzalez-Meler, M. A.

    2014-12-01

    Climate forcing factors have been documented to directly (e.g. CO2 fertilization) or indirectly (e.g. temperature and vapor pressure deficit) affect net primary productivity (NPP) of forests. Climate variations can also affect the vulnerability of forests to pests and pathogens, causing diffuse or widespread mortality. The introduction of novel pests is causing rapid mortality of targeted species with undetermined effects on forest productivity: NPP could decrease or increase depending on the severity (proportion of basal area impacted) and species diversity. We attempted to document the impact of diffuse mortality caused by insect outbreaks on North American temperate forests through synthesis of literature. Despite the large number of studies (>500) only a few (12) documented NPP in a systematic manner. The magnitude of insect and pathogen disturbance was larger in western than eastern forests due to the redundancy and functional diversity of temperate deciduous and mixed deciduous forests. Recovery from disturbance was more rapid from diffuse short duration defoliation events relative to the long lasting impacts of wood boring insects. Forest resilience may decrease as insect disturbance increases, particularly with generalist invasive pests that target a variety of species. We conclude that these biotic interactions, particularly when caused by invasive pests, impose biological forcing to forest NPP at similar magnitude and time scales than climate forcing.

  2. Insect pathogens as biological control agents: Back to the future.

    PubMed

    Lacey, L A; Grzywacz, D; Shapiro-Ilan, D I; Frutos, R; Brownbridge, M; Goettel, M S

    2015-11-01

    The development and use of entomopathogens as classical, conservation and augmentative biological control agents have included a number of successes and some setbacks in the past 1years. In this forum paper we present current information on development, use and future directions of insect-specific viruses, bacteria, fungi and nematodes as components of integrated pest management strategies for control of arthropod pests of crops, forests, urban habitats, and insects of medical and veterinary importance. Insect pathogenic viruses are a fruitful source of microbial control agents (MCAs), particularly for the control of lepidopteran pests. Most research is focused on the baculoviruses, important pathogens of some globally important pests for which control has become difficult due to either pesticide resistance or pressure to reduce pesticide residues. Baculoviruses are accepted as safe, readily mass produced, highly pathogenic and easily formulated and applied control agents. New baculovirus products are appearing in many countries and gaining an increased market share. However, the absence of a practical in vitro mass production system, generally higher production costs, limited post application persistence, slow rate of kill and high host specificity currently contribute to restricted use in pest control. Overcoming these limitations are key research areas for which progress could open up use of insect viruses to much larger markets. A small number of entomopathogenic bacteria have been commercially developed for control of insect pests. These include several Bacillus thuringiensis sub-species, Lysinibacillus (Bacillus) sphaericus, Paenibacillus spp. and Serratia entomophila. B. thuringiensis sub-species kurstaki is the most widely used for control of pest insects of crops and forests, and B. thuringiensis sub-species israelensis and L. sphaericus are the primary pathogens used for control of medically important pests including dipteran vectors. These pathogens

  3. A Pathogenic Nematode Targets Recognition Proteins to Avoid Insect Defenses

    PubMed Central

    Toubarro, Duarte; Avila, Mónica Martinez; Montiel, Rafael; Simões, Nelson

    2013-01-01

    Steinernemacarpocapsae is a nematode pathogenic in a wide variety of insect species. The great pathogenicity of this nematode has been ascribed to its ability to overcome the host immune response; however, little is known about the mechanisms involved in this process. The analysis of an expressed sequence tags (EST) library in the nematode during the infective phase was performed and a highly abundant contig homologous to serine protease inhibitors was identified. In this work, we show that this contig is part of a 641-bp cDNA that encodes a BPTI-Kunitz family inhibitor (Sc-KU-4), which is up-regulated in the parasite during invasion and installation. Recombinant Sc-KU-4 protein was produced in Escherichia coli and shown to inhibit chymotrypsin and elastase activities in a dose-dependent manner by a competitive mechanism with Ki values of 1.8 nM and 2.6 nM, respectively. Sc-KU-4 also inhibited trypsin and thrombin activities to a lesser extent. Studies of the mode of action of Sc-KU-4 and its effects on insect defenses suggest that although Sc-KU-4 did not inhibit the activation of hemocytes or the formation of clotting fibers, it did inhibit hemocyte aggregation and the entrapment of foreign particles by fibers. Moreover, Sc-KU-4 avoided encapsulation and the deposition of clotting materials, which usually occurs in response to foreign particles. We show by protein-protein interaction that Sc-KU-4 targets recognition proteins of insect immune system such as masquerade-like and serine protease-like homologs. The interaction of Sc-KU-4 with these proteins explains the ability of the nematode to overcome host reactions and its large pathogenic spectrum, once these immune proteins are well conserved in insects. The discovery of this inhibitor targeting insect recognition proteins opens new avenues for the development of S. carpocapsae as a biological control agent and provides a new tool to study host-pathogen interactions. PMID:24098715

  4. DESCRIPTION AND ANALYSIS OF TWO INTERNET-BASED DATABASES OF INSECT PATHOGENS: EDWIP AND VIDIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 1996, two searchable databases covering insect pathogens were posted on the World Wide Web: the Ecological Database of the World's Insect Pathogens (EDWIP) and the Viral Diseases of Insects in the Literature database (VIDIL). In this paper, we describe the format and contents of EDWIP and VIDIL ...

  5. Historical and current roles of insects and pathogens in eastern Oregon and Washington forested landscapes. Forest Service general technical report

    SciTech Connect

    Hessburg, P.F.; Mitchell, R.G.; Filip, G.M.

    1994-04-01

    The paper examines, by climax conifer series, historical and current roles of many important pathogens and insects of interior Northwest coniferious forests and their unique responses to changing successional conditions resulting from management. Future research on forest pathogens and insects should address three primary subject areas: insect and pathogen population dynamics in managed and unmanaged forests; ecological roles and effects of native and introduced pathogens and insects; and effects of natural disturbances and management practices on native insects, pathogens, and their natural enemies.

  6. A Theoretical Assessment of Methods to Reduce the Spread of Insect Vectored Plant Pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many insect vectored plant pathogen systems share several common features. Specifically, insect vectors often prefer habitats outside the affected crop and acquire the pathogen from a non-crop plant host. Inoculative vectors then move into the crop, causing primary pathogen spread. This may or ma...

  7. [Variability in esterases of Metarhizium anisopliae].

    PubMed

    Estrada-Martínez, M E; Piñón, D R; Capote, M C

    1997-03-01

    The variability in esterases of the entomogenous fungus Metarhizium anisopliae was determined electrophoretically on 8.5% polyacrylamide gel. Ten isolates from diverse taxonomic groups of insects were analyzed. The electrophoretic analysis showed differences and similarities between these isolates and it was possible to distinguish six different patterns. The results obtained show a great polymorphism for the esterase system of M. anisopliae. PMID:15482022

  8. Production of Microsclerotia of the Fungal Entomopathogen Metarhizium anisopliae and Their Use as a Biocontrol Agent for Soil-Inhabiting Insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three strains of Metarhizium anisopliae, F52, TM109, and Ma1200, were evaluated for growth and propagule formation in shake flask studies using media with varying carbon concentrations and carbon-to-nitrogen ratios. Under the conditions of this study, all strains produced blastospores and microscle...

  9. Pathogen alarm behavior in a termite: A new form of communication in social insects

    PubMed

    Rosengaus; Jordan; Lefebvre; Traniello

    1999-11-01

    Dampwood termites, Zootermopsis angusticollis, show an alarm response after detecting the presence of spores of the pathogenic fungus Metarhizium anisopliae. Termites in direct contact with a high concentration of spores (10(7) spores/ml) show a striking vibratory display which appears to convey information about the presence of pathogens to nearby unexposed nestmates through substrate vibration. Nestmates not directly in contact with spores that perceive the vibrational signal increase significantly their distance from the spore-exposed vibrating termites, apparently to escape from the source of infection. The fleeing response is not induced by the presence of the spores alone or by pheromones, and requires the perception of the vibrations propagated through the substrate. This "pathogen alarm behavior" appears to be a previously unrecognized communication mechanism that allows termites to reduce disease risks within the nest. PMID:10551951

  10. Pathogen Alarm Behavior in a Termite: A New Form of Communication in Social Insects

    NASA Astrophysics Data System (ADS)

    Rosengaus, R. B.; Jordan, C.; Lefebvre, M. L.; Traniello, J. F. A.

    Dampwood termites, Zootermopsis angusticollis, show an alarm response after detecting the presence of spores of the pathogenic fungus Metarhizium anisopliae. Termites in direct contact with a high concentration of spores (107 spores/ml) show a striking vibratory display which appears to convey information about the presence of pathogens to nearby unexposed nestmates through substrate vibration. Nestmates not directly in contact with spores that perceive the vibrational signal increase significantly their distance from the spore-exposed vibrating termites, apparently to escape from the source of infection. The fleeing response is not induced by the presence of the spores alone or by pheromones, and requires the perception of the vibrations propagated through the substrate. This "pathogen alarm behavior" appears to be a previously unrecognized communication mechanism that allows termites to reduce disease risks within the nest.

  11. 7 CFR 305.40 - Garbage treatment schedules for insect pests and pathogens.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Garbage treatment schedules for insect pests and pathogens. 305.40 Section 305.40 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL... Garbage § 305.40 Garbage treatment schedules for insect pests and pathogens. (a) T415-a, heat...

  12. Local adaptation of an introduced transgenic insect fungal pathogen due to new beneficial mutations.

    PubMed

    Wang, Sibao; O'Brien, Tammatha R; Pava-Ripoll, Monica; St Leger, Raymond J

    2011-12-20

    Genetically modified Metarhizium spp represent a major new arsenal for combating insect pests and insect-borne diseases. However, for these tools to be used safely and effectively, we need a much better understanding of their evolutionary potential and invasion ecology. In order to model natural as well as anthropogenic dispersal scenarios, we investigated evolutionary processes in a green fluorescent protein tagged strain of Metarhizium robertsii following transfer from a semitropical to a temperate soil community. Adaptive changes occurred over four years despite recurrent genetic bottlenecks and lack of recombination with locally well adapted strains. By coupling microarray-based functional analysis with DNA hybridizations we determined that expression of cell wall and stress response genes evolved at an accelerated rate in multiple replicates, whereas virulence determinants, transposons, and chromosome structure were unaltered. The mutable genes were enriched for TATA boxes possibly because they are larger mutational targets. In further field trials, we showed that the new mutations increased the fitness of M. robertsii in the new range by enhancing saprophytic associations, and these benefits were maintained in subsequent years. Consistent with selection being habitat rather than host specific, populations of an avirulent mutant cycled with seasons similarly to the wild type, whereas a mutant unable to adhere to plant roots showed a linear decrease in population. Our results provide a mechanistic basis for understanding postrelease adaptations, show that agents can be selected that lack gene flow and virulence evolution, and describe a means of genetically containing transgenic strains by disrupting the Mad2 gene. PMID:22143757

  13. Brevibacillus laterosporus inside the insect body: Beneficial resident or pathogenic outsider?

    PubMed

    Marche, Maria Giovanna; Mura, Maria Elena; Ruiu, Luca

    2016-06-01

    Brevibacillus laterosporus is an entomopathogenic bacterium showing varying degrees of virulence against diverse insect pests. Conversely, it is regarded as a beneficial component of the intestinal flora in different animals and in some insect species including the honeybee. B. laterosporus was detected through a species-specific PCR assay in the body of different insects, including Apis mellifera and Bombus terrestris. A strain isolated from a honeybee worker was pathogenic to the house fly Musca domestica, thus supporting the development of either mutualistic or pathogenic interactions of this bacterium with diverse insect species, as the result of a coevolutionary process. PMID:27180901

  14. Insecticidal Pilin Subunit from the Insect Pathogen Xenorhabdus nematophila

    PubMed Central

    Khandelwal, Puneet; Choudhury, Devapriya; Birah, Ajanta; Reddy, M. K.; Gupta, Gorakh Prasad; Banerjee, Nirupama

    2004-01-01

    Xenorhabdus nematophila is an insect pathogen and produces protein toxins which kill the larval host. Previously, we characterized an orally toxic, large, outer membrane-associated protein complex from the culture medium of X. nematophila. Here, we describe the cloning, expression, and characterization of a 17-kDa pilin subunit of X. nematophila isolated from that protein complex. The gene was amplified by PCR, cloned, and expressed in Escherichia coli. The recombinant protein was refolded in vitro in the absence of its cognate chaperone by using a urea gradient. The protein oligomerized during in vitro refolding, forming multimers. Point mutations in the conserved N-terminal residues of the pilin protein greatly destabilized its oligomeric organization, demonstrating the importance of the N terminus in refolding and oligomerization of the pilin subunit by donor strand complementation. The recombinant protein was cytotoxic to cultured Helicoverpa armigera larval hemocytes, causing agglutination and subsequent release of the cytoplasmic enzyme lactate dehydrogenase. The agglutination of larval cells by the 17-kDa protein was inhibited by several sugar derivatives. The biological activity of the purified recombinant protein indicated that it has a conformation similar to that of the native protein. The 17-kDa pilin subunit was found to be orally toxic to fourth- or fifth-instar larvae of an important crop pest, H. armigera, causing extensive damage to the midgut epithelial membrane. To our knowledge, this is first report describing an insecticidal pilin subunit of a bacterium. PMID:15375127

  15. Differentially-expressed glycoproteins in Locusta migratoria hemolymph infected with Metarhizium anisopliae.

    PubMed

    Wang, Chutao; Cao, Yueqing; Wang, Zhongkang; Yin, Youping; Peng, Guoxiong; Li, Zhenlun; Zhao, Hua; Xia, Yuxian

    2007-11-01

    Glycoproteins play important roles in insect physiology. Infection with pathogen always results in the differential expression of some glycoproteins, which may be involved in host-pathogen interactions. In this report, differentially-expressed glycoproteins from the hemolymph of locusts infected with Metarhizium anisopliae were analyzed by two-dimensional electrophoresis (2-DE) and PDQuest software. The results showed that 13 spots were differentially expressed, of which nine spots were upregulated and four were downregulated. Using MS/MS with de novo sequencing and NCBI database searches, three upregulated proteins were identified as locust transferrin, apolipoprotein precursor, and hexameric storage protein 3. These proteins have been reported to be involved in the insect innate immune response to microbial challenge. Due to the limited available genome information and protein sequences of locusts, the possible functions of the other 10 differentially-expressed spots remain unknown. PMID:17658547

  16. Production of destruxins from Metarhizium spp. fungi in artificial medium and in endophytically colonized Cowpea Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Destruxins (DTXs) are cyclic depsipeptides produced by many Metarhizium isolates that have long been assumed to contribute to virulence of these entomopathogenic fungi. We evaluated the virulence of 20 Metarhizium isolates against insect larvae and measured the concentration of DTXs A, B, and E prod...

  17. Production of destruxins from metarhizium spp. fungi in artificial medium and in endophytically colonized cowpea plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Destruxins (DTXs) are cyclic depsipeptides produced by many Metarhizium isolates that have long been assumed to contribute to virulence of these entomopathogenic fungi. We evaluated the virulence of 20 Metarhizium isolates against insect larvae and measured the concentration of DTXs A, B, and E prod...

  18. Different Effects of Metarhizium anisopliae Strains IMI330189 and IBC200614 on Enzymes Activities and Hemocytes of Locusta migratoria L.

    PubMed Central

    Cao, Guangchun; Jia, Miao; Zhao, Xia; Wang, Lei; Tu, Xiongbing; Wang, Guangjun; Nong, Xiangqun; Zhang, Zehua

    2016-01-01

    Background Metarhizium is an important class of entomopathogenic fungi in the biocontrol of insects, but its virulence is affected by insect immunity. To clarify the mechanism in virulence of Metarhizium, we compared the immunological differences in Locusta migratoria L. when exposed to two strains of Metarhizium anisopliae (Ma). Results The virulence of Ma IMI330189 was significantly higher than that of Ma IBC200614 to locust, and IMI330189 overcame the hemocytes and began destroying the hemocytes of locust at 72 h after spray, while locust is immune to IBC200614. IMI330189 could overcome the humoral immunity of locust by inhibiting the activities of phenol oxidase (PO), esterases, multi-function oxidases (MFOs) and acetylcholinesterases in locust while increasing the activities of glutathione-S-transferases (GSTs), catalase and aryl-acylamidase (AA). However IBC200614 inhibit the activities of GSTs and AA in locust and increase the activities of MFOs, PO, superoxide dismutase, peroxidase and chitinase in locust. The changes of enzymes activities in period of infection showed that the time period between the 2nd and the 5th day after spray is critical in the pathogenic process. Conclusion These results found the phenomenon that Ma initiatively broke host hemocytes, revealed the correlation between the virulence of Ma and the changes of enzymes activities in host induced by Ma, and clarified the critical period in the infection of Ma. So, these results should provide guidance for the construction of efficient biocontrol Ma strains. PMID:27227835

  19. Transgenic tobacco expressing a modified spider peptide inhibits the growth of plant pathogens and insect larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The gene encoding lycotoxin I, an amphipathic pore-forming peptide, was modified to increase oral toxicity to insects. One of the most active modified genes was then constitutively expressed in tobacco (Nicotiana tabacum) and transformants were evaluated for insect and disease resistance. Pathogenic...

  20. Immunity in a Social Insect

    NASA Astrophysics Data System (ADS)

    Rosengaus, Rebeca B.; Traniello, James F. A.; Chen, Tammy; Brown, Julie J.; Karp, Richard D.

    Although pathogens appear to have exerted significant selective pressure on various aspects of sociality, mechanisms of disease resistance in the social insects are poorly understood. We report here on an immune response to infection by the dampwood termite, Zootermopsis angusticollis. Nymphs immunized with an injection of 7.6×107, 7.6×105, or 7.6×104 cells/ml glutaraldehyde-killed solution of the bacterium Pseudomonas aeruginosa had significantly higher survivorship than controls following a challenge with a lethal concentration of active bacteria. Similarly, nymphs exposed to a 9×10-1 spores/ml suspension of the fungus Metarhizium anisopliae had higher survivorship than controls after a challenge with a lethal concentration of spores. Prior exposure to a pathogen thus conferred upon termites a degree of protection during a subsequent encounter with the same pathogen. This represents the first demonstration of immune function in vivo in a social insect.

  1. Different pathogenicities of Rice stripe virus from the insect vector and from viruliferous plants.

    PubMed

    Zhao, Wan; Yang, Pengcheng; Kang, Le; Cui, Feng

    2016-04-01

    Persistent plant viruses usually depend on insects for their transmission; they cannot be transmitted between plants or through mechanical inoculation. However, the mechanism by which persistent viruses become pathogenic in insect vectors remains unknown. In this study, we used Rice stripe virus (RSV), its insect vector Laodelphax striatellus and host plant (Oryza sativa) to explore how persistent viruses acquire pathogenicity from insect vectors. RSV acquired phytopathogenicity in both the alimentary tract and the salivary gland of L. striatellus. We mechanically inoculated RSV into rice O. sativa leaves through midrib microinjection. Insect-derived RSV induced a typical stripe symptom, whereas plant-derived RSV only produced chlorosis in rice leaves. Insect-derived RSV had higher expression of genes rdrp, ns2, nsvc2, sp and nsvc4 than plant-derived RSV, and the latter had higher expression of genes cp and ns3 than the former in rice leaves. Different from plant-derived RSV, insect-derived RSV damaged grana stacks within the chloroplast and inhibited photosynthesis by suppressing the photosystem II subunit psbp. This study not only presented a convenient method to mechanically inoculate RSV into plants, but also provided insights into the different pathogenic mechanisms of RSV from the insect vector and from viruliferous plants. PMID:26585422

  2. Transmission of Insect-Vectored Pathogens: Effects of Vector Fitness as a Function of Infectivity Status

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The spread of insect vectored pathogens is dependent on the population dynamics of the vector. Epidemiology models typically assume that birth and death rates of pathogen-free and inoculative vectors are equal, an assumption which is not true for all pathosystems. Here a series of simple and gener...

  3. ADDITIVE IMPACTS OF PLANT PATHOGEN-INSECT ENHANCES PEST-PLANT CONTROL EFFICACY: EXPERIMENTAL EVIDENCE FROM THE RUST-INSECT-MELALEUCA SYSTEM.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant pathogen-insect integration is becoming popular in pest plant control programs. Herein, we tested the impacts of pathogen-herbivorous insect integration in the biological control of a pest tree, Melaleuca quinquenervia (melaleuca). Melaleuca trees were cut at 25-cm above ground, allowed to cop...

  4. MALDI-TOF mass spectrometry applied to identifying species of insect-pathogenic fungi from the Metarhizium anisopliae complex

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has proven to be a powerful tool for taxonomic resolution of microorganisms. In this proof-of-concept study, we assessed the effectiveness of this technique to track the current gene sequence-based phylogenet...

  5. An insect pathogenic symbiosis between a Caenorhabditis and Serratia

    PubMed Central

    Morrison, Julie; Cooper, Vaughn; Thomas, W. Kelley

    2011-01-01

    We described an association between a strain of the nematode Caenorhabditis briggsae, i.e. KT0001, and the bacteria Serratia sp. SCBI (South African Caenorhabditis briggsae isolate), which was able to kill the insect Galleria (G. mellonella). Here we show that the Serratia sp. SCBI lines the gut of the nematode, similar to the Heterorhabditis-Photorhabdus complex, indicating that the association is possibly internal. We also expand on the relevance of this tripartite, i.e. insect-nematode-bacteria, interaction in the broader evolutionary context and Caenorhabditis natural history. PMID:21389770

  6. Microsporidia Biological Control Agents and Pathogens of Beneficial Insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microsporidian infections of insects are generally chronic, causing subtle pathologies of reduced fecundity and shorter lifespans. The lack of acute infections that cause rapid mortality, make microsporida ill-suited as biopesticides for arthropod control. Instead, they are considered to be more use...

  7. IDENTIFICATION OF ALLERGENS FROM METARHIZIUM ANISOPLIAE USING MASS SPECTROMETRY

    EPA Science Inventory

    Background
    The U.S. EPA, under the "Children at Risk" Program, is currently addressing the problem of indoor fungal bioaerosol contamination. The fungus Metarhizium Anisopliae has been used as a bio-pesticide for insect control since the 1800's. Recent studies have shown t...

  8. Metarhizium anisopliae infection alters feeding and trophallactic behavior in the ant Solenopsis invicta.

    PubMed

    Qiu, Hua-Long; Lu, Li-Hua; Zalucki, M P; He, Yu-Rong

    2016-07-01

    In social insects, social behavior may be changed in a way that preventing the spread of pathogens. We infected workers of the ant Solenopsis invicta with an entomopathogenic fungus Metarhizium anisopliae and then videotaped and/or measured worker feeding and trophallactic behavior. Results showed that fungal infected S. invicta enhanced their preference for bitter alkaloid chemical quinine on 3days after inoculation, which might be self-medication of S. invicta by ingesting more alkaloid substances in response to pathogenic infection. Furthermore, infected ants devoted more time to trophallactic behavior with their nestmates on 3days post inoculation, in return receiving more food. Increased interactions between exposed ants and their naive nestmates suggest the existence of social immunity in S. invicta. Overall, our study indicates that S. invicta may use behavioral defenses such as self-medication and social immunity in response to a M. anisopliae infection. PMID:27234423

  9. Effect of Infection by Beauveria bassiana and Metarhizium anisopliae on the Feeding of Uvarovistia zebra

    PubMed Central

    Mohammadbeigi, A.; Port, G.

    2015-01-01

    To identify the susceptibility of long-horned grasshoppers to entomopathogenic fungi, the effect of infection with the fungi Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) on food consumption by Uvarovistia zebra (Uvarov) (Orthoptera: Tettigoniidae) was investigated. Preliminary results showed that both fungi had a negative effect on food consumption of the insects. For both fungi a significant reduction of food consumption and faeces production by insects were observed between the highest spore concentration (5 × 106 spores/ml) and other treatments. Compared with control insects, the insects treated with 5 × 106 spores/ml of B. bassiana and M. anisopliae showed 60 and 63% reduction in mean food consumption/insect, respectively. The corrected cumulative percent mortality of the insects treated with the highest concentration of B. bassiana and M. anisopliae were 57.7 and 55.5%, respectively. This was the first account of these entomopathogenic fungi being used against a species from this family, therefore based on the results obtained from this research, it could be said that the fungi have pathogenicity effect on U. zebra as a long-horned grasshopper.

  10. Responses of temperate forest productivity to insect and pathogen disturbances.

    PubMed

    Flower, Charles E; Gonzalez-Meler, Miquel A

    2015-01-01

    Pest and pathogen disturbances are ubiquitous across forest ecosystems, impacting their species composition, structure, and function. Whereas severe abiotic disturbances (e.g., clear-cutting and fire) largely reset successional trajectories, pest and pathogen disturbances cause diffuse mortality, driving forests into nonanalogous system states. Biotic perturbations that disrupt forest carbon dynamics either reduce or enhance net primary production (NPP) and carbon storage, depending on pathogen type. Relative to defoliators, wood borers and invasive pests have the largest negative impact on NPP and the longest recovery time. Forest diversity is an important contributing factor to productivity: NPP is neutral, marginally enhanced, or reduced in high-diversity stands in which a small portion of the canopy is affected (temperate deciduous or mixed forests) but very negative in low-diversity stands in which a large portion of the canopy is affected (western US forests). Pests and pathogens reduce forest structural and functional redundancy, affecting their resilience to future climate change or new outbreaks. Therefore, pests and pathogens can be considered biotic forcing agents capable of causing consequences of similar magnitude to climate forcing factors. PMID:25580836

  11. Influence of temperature on the physiology and virulence of the insect pathogen Serratia sp. Strain SCBI.

    PubMed

    Petersen, Lauren M; Tisa, Louis S

    2012-12-01

    The physiology of a newly recognized Serratia species, termed South African Caenorhabditis briggsae Isolate (SCBI), which is both a nematode mutualist and an insect pathogen, was investigated and compared to that of Serratia marcescens Db11, a broad-host-range pathogen. The two Serratia strains had comparable levels of virulence for Manduca sexta and similar cytotoxic activity patterns, but motility and lipase and hemolytic activities differed significantly between them. PMID:23042169

  12. The acid trehalase, ATM1, contributes to the in vivo growth and virulence of the entomopathogenic fungus, Metarhizium acridum.

    PubMed

    Jin, Kai; Peng, Guoxiong; Liu, Yingchun; Xia, Yuxian

    2015-04-01

    For pathogens, the ability to acquire available nutrients in a host is a key to their survival and replication. Entomopathogenic fungi of the genus Metarhizium secrete trehalase, which enables them to use trehalose, the predominant sugar in insects. Here, the roles of the acid trehalase gene (ATM1) in the in vivo growth and virulence of Metarhizium acridum were investigated. Phenotypic analysis showed that disruption of ATM1 severely reduced fungal growth on exogenous trehalose as the sole carbon source. Bioassays showed that ATM1 disruption impaired the virulence of M. acridum against the host insect Locusta migratoria. The ATM1-disruption strain (ΔATM1) grown more slowly than the wild-type strain (WT) and complemented transformant (CP) in locust blood, which was consistent with the activity of acid trehalase in the hemolymph of infected locusts. Correspondingly, the trehalose concentration in locusts infected by ΔATM1 was significantly higher than in those infected by WT or CP. Thus, ATM1 disruption led to a significant reduction in virulence by adversely affecting the fungal growth in insect hemolymph, which resulted from the inability of the mutant strain to use trehalose. PMID:25865794

  13. Modeling the spread of insect transmitted plant pathogens: roguing in perennial crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Roguing (the removal of infected plants) is commonly used to manage the spread of insect-transmitted plant pathogens. In the case of perennial crops, rogued plants are often replaced with healthy plants. Replacement of infected plants has two potential benefits. First, removing an infected plant e...

  14. A novel method for infecting Drosophila adult flies with insect pathogenic nematodes

    PubMed Central

    Castillo, Julio Cesar; Shokal, Upasana; Eleftherianos, Ioannis

    2012-01-01

    Drosophila has been established as an excellent genetic and genomic model to investigate host-pathogen interactions and innate immune defense mechanisms. To date, most information on the Drosophila immune response derives from studies that involve bacterial, fungal or viral pathogens. However, immune reactions to insect parasitic nematodes are still not well characterized. The nematodes Heterorhabditis bacteriophora live in symbiosis with the entomopathogenic bacteria Photorhabdus luminescens, and they are able to invade and kill insects. Interestingly, Heterorhabditis nematodes are viable in the absence of Photorhabdus. Techniques for infecting Drosophila larvae with these nematodes have been previously reported. Here, we have developed a method for infecting Drosophila adult flies with Heterorhabditis nematodes carrying (symbiotic worms) or lacking (axenic worms) their associated bacteria. The protocol we present can be readily adapted for studying parasitic strategies of other insect nematodes using Drosophila as the host infection model. PMID:22546901

  15. Potential nontarget effects of Metarhizium anisopliae (Deuteromycetes) used for biological control of ticks (Acari: Ixodidae)

    USGS Publications Warehouse

    Ginsberg, H.S.; LeBrun, R.A.; Heyer, K.; Zhioua, E.

    2002-01-01

    The potential for nontarget effects of the entomopathogenic fungus Metarhizium anisopliae (Metschnikoff) Sorokin, when used for biological control of ticks, was assessed in laboratory trials. Fungal pathogenicity was studied against convergent ladybird beetles, Hippodamia convergens Gue??rin-Me??neville, house crickets, Acheta domesticus (L.), and the milkweed bugs Oncopeltus fasciatus (Dallas). Fungal spores applied with a spray tower produced significant mortality in H. convergens and A. domesticus, but effects on O. fasciatus were marginal. Placing treated insects with untreated individuals resulted in mortality from horizontal transmission to untreated beetles and crickets, but not milkweed bugs. Spread of fungal infection in the beetles resulted in mortality on days 4-10 after treatment, while in crickets mortality was on day 2 after treatment, suggesting different levels of pathogenicity and possibly different modes of transmission. Therefore, M. anisopliae varies in pathogenicity to different insects. Inundative applications can potentially affect nontarget species, but M. anisopliae is already widely distributed in North America, so applications for tick control generally would not introduce a novel pathogen into the environment. Pathogenicity in lab trials does not, by itself, demonstrate activity under natural conditions, so field trials are needed to confirm these results and to assess methods to minimize nontarget exposure.

  16. Potential nontarget effects of Metarhizium anisopliae (Deuteromycetes) used for biological control of ticks (Acari: Ixodidae)

    USGS Publications Warehouse

    Ginsberg, H.S.; LeBrun, R.A.; Heyer, K.; Zhioua, E.

    2002-01-01

    The potential for nontarget effects of the entomopathogenic fungus Metarhizium anisopliae (Metschnikoff) Sorokin, when used for biological control of ticks, was assessed in laboratory trials. Fungal pathogenicity was studied against convergent ladybird beetles, Hippodamia convergens Guerin-Meneville, house crickets, Acheta domesticus (L.), and milkweed bugs, Oncopeltus fasciatus (Dallas). Fungal spores applied with a spray tower produced significant mortality in H. convergens and A. domesticus, but effects on O. fasciatus were marginal. Treated insects placed with untreated individuals resulted in mortality from horizontal transmission to untreated beetles and crickets, but not milkweed bugs. Spread of fungal infection in the beetles resulted in mortality on days 4-10 after treatment, while in crickets mortality was on day 2 after treatment, suggesting different levels of pathogenicity and possibly different modes of transmission. Therefore, M. anisopliae varies in pathogenicity to different insects. Inundative applications can potentially affect nontarget species, but M. anisopliae is already widely distributed in North America, so applications for tick control generally would not introduce a novel pathogen into the environment. Pathogenicity in lab trials does not, by itself, demonstrate activity under natural conditions, so field trials are needed to confirm these results and to assess methods to minimize nontarget exposure.

  17. O antigen modulates insect vector acquisition of the bacterial plant pathogen Xylella fastidiosa.

    PubMed

    Rapicavoli, Jeannette N; Kinsinger, Nichola; Perring, Thomas M; Backus, Elaine A; Shugart, Holly J; Walker, Sharon; Roper, M Caroline

    2015-12-01

    Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen. PMID:26386068

  18. O Antigen Modulates Insect Vector Acquisition of the Bacterial Plant Pathogen Xylella fastidiosa

    PubMed Central

    Rapicavoli, Jeannette N.; Kinsinger, Nichola; Perring, Thomas M.; Backus, Elaine A.; Shugart, Holly J.; Walker, Sharon

    2015-01-01

    Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen. PMID:26386068

  19. Insect peptide metchnikowin confers on barley a selective capacity for resistance to fungal ascomycetes pathogens

    PubMed Central

    Rahnamaeian, Mohammad; Langen, Gregor; Imani, Jafargholi; Khalifa, Walaa; Altincicek, Boran; von Wettstein, Diter; Kogel, Karl-Heinz; Vilcinskas, Andreas

    2009-01-01

    The potential of metchnikowin, a 26-amino acid residue proline-rich antimicrobial peptide synthesized in the fat body of Drosophila melanogaster was explored to engineer disease resistance in barley against devastating fungal plant pathogens. The synthetic peptide caused strong in vitro growth inhibition (IC50 value ∼1 μM) of the pathogenic fungus Fusarium graminearum. Transgenic barley expressing the metchnikowin gene in its 52-amino acid pre-pro-peptide form under the control of the inducible mannopine synthase (mas) gene promoter from the Ti plasmid of Agrobacterium tumefaciens displayed enhanced resistance to powdery mildew as well as Fusarium head blight and root rot. In response to these pathogens, metchnikowin accumulated in plant apoplastic space, specifying that the insect signal peptide is functional in monocotyledons. In vitro and in vivo tests revealed that the peptide is markedly effective against fungal pathogens of the phylum Ascomycota but, clearly, less active against Basidiomycota fungi. Importantly, germination of the mutualistic basidiomycete mycorrhizal fungus Piriformospora indica was affected only at concentrations beyond 50 μM. These results suggest that antifungal peptides from insects are a valuable source for crop plant improvements and their differential activities toward different phyla of fungi denote a capacity for insect peptides to be used as selective measures on specific plant diseases. PMID:19734262

  20. Spread of plant pathogens and insect vectors at the northern range margin of cypress in Italy

    NASA Astrophysics Data System (ADS)

    Zocca, Alessia; Zanini, Corrado; Aimi, Andrea; Frigimelica, Gabriella; La Porta, Nicola; Battisti, Andrea

    2008-05-01

    The Mediterranean cypress ( Cupressus sempervirens) is a multi-purpose tree widely used in the Mediterranean region. An anthropogenic range expansion of cypress has taken place at the northern margin of the range in Italy in recent decades, driven by ornamental planting in spite of climatic constraints imposed by low winter temperature. The expansion has created new habitats for pathogens and pests, which strongly limit tree survival in the historical (core) part of the range. Based on the enemy release hypothesis, we predicted that damage should be lower in the expansion area. By comparing tree and seed cone damage by pathogens and pests in core and expansion areas of Trentino, a district in the southern Alps, we showed that tree damage was significantly higher in the core area. Seed cones of C. sempervirens are intensively colonized by an aggressive and specific pathogen (the canker fungus Seiridium cardinale, Coelomycetes), associated with seed insect vectors Megastigmus wachtli (Hymenoptera Torymidae) and Orsillus maculatus (Heteroptera Lygaeidae). In contrast, we observed lower tree damage in the expansion area, where a non-aggressive fungus ( Pestalotiopsis funerea, Coelomycetes) was more frequently associated with the same insect vectors. Our results indicate that both insect species have a great potential to reach the range margin, representing a continuous threat of the arrival of fungal pathogens to trees planted at extreme sites. Global warming may accelerate this process since both insects and fungi profit from increased temperature. In the future, cypress planted at the range margin may then face similar pest and pathogen threats as in the historical range.

  1. Molecular genetics of secondary chemistry in Metarhizium fungi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As with many microbes, entomopathogenic fungi from the genus Metarhizium produce a plethora of small molecule metabolites, often referred to as secondary metabolites. Although these intriguing compounds are a conspicuous feature of the biology of the producing fungi, their roles in pathogenicity and...

  2. Spread of insect-vectored plant pathogens: use of simulation models to assess the role of ecological and operational factors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The spread of insect-vectored pathogens is dependent on many factors. As a consequence, it is often difficult to predict effects of manipulating one or more factors on pathogen spread. One method to aid in understanding the role of ecological and operational factors on pathogen spread is the use o...

  3. MrSkn7 controls sporulation, cell wall integrity, autolysis, and virulence in Metarhizium robertsii.

    PubMed

    Shang, Yanfang; Chen, Peilin; Chen, Yixiong; Lu, Yuzhen; Wang, Chengshu

    2015-04-01

    Two-component signaling pathways generally include sensor histidine kinases and response regulators. We identified an ortholog of the response regulator protein Skn7 in the insect-pathogenic fungus Metarhizium robertsii, which we named MrSkn7. Gene deletion assays and functional characterizations indicated that MrSkn7 functions as a transcription factor. The MrSkn7 null mutant of M. robertsii lost the ability to sporulate and had defects in cell wall biosynthesis but was not sensitive to oxidative and osmotic stresses compared to the wild type. However, the mutant was able to produce spores under salt stress. Insect bioassays using these spores showed that the virulence of the mutant was significantly impaired compared to that of the wild type due to the failures to form the infection structure appressorium and evade host immunity. In particular, deletion of MrSkn7 triggered cell autolysis with typical features such as cell vacuolization, downregulation of repressor genes, and upregulation of autolysis-related genes such as extracellular chitinases and proteases. Promoter binding assays confirmed that MrSkn7 could directly or indirectly control different putative target genes. Taken together, the results of this study help us understand the functional divergence of Skn7 orthologs as well as the mechanisms underlying the development and control of virulence in insect-pathogenic fungi. PMID:25710964

  4. Trade-offs shape the evolution of the vector-borne insect pathogen Xenorhabdus nematophila.

    PubMed

    Chapuis, Elodie; Arnal, Audrey; Ferdy, Jean-Baptiste

    2012-07-01

    Our current understanding on how pathogens evolve relies on the hypothesis that pathogens' transmission is traded off against host exploitation. In this study, we surveyed the possibility that trade-offs determine the evolution of the bacterial insect pathogen, Xenorhabdus nematophila. This bacterium rapidly kills the hosts it infects and is transmitted from host cadavers to new insects by a nematode vector, Steinernema carpocapsae. In order to detect trade-offs in this biological system, we produced 20 bacterial lineages using an experimental evolution protocol. These lineages differ, among other things, in their virulence towards the insect host. We found that nematode parasitic success increases with bacteria virulence, but their survival during dispersal decreases with the number of bacteria they carry. Other bacterial traits, such as production of the haemolytic protein XaxAB, have a strong impact on nematode reproduction. We then combined the result of our measurements with an estimate of bacteria fitness, which was divided into a parasitic component and a dispersal component. Contrary to what was expected in the trade-off hypothesis, we found no significant negative correlation between the two components of bacteria fitness. Still, we found that bacteria fitness is maximized when nematodes carry an intermediate number of cells. Our results therefore demonstrate the existence of a trade-off in X. nematophila, which is caused, in part, by the reduction in survival this bacterium causes to its nematode vectors. PMID:22398163

  5. Trade-offs shape the evolution of the vector-borne insect pathogen Xenorhabdus nematophila

    PubMed Central

    Chapuis, Élodie; Arnal, Audrey; Ferdy, Jean-Baptiste

    2012-01-01

    Our current understanding on how pathogens evolve relies on the hypothesis that pathogens' transmission is traded off against host exploitation. In this study, we surveyed the possibility that trade-offs determine the evolution of the bacterial insect pathogen, Xenorhabdus nematophila. This bacterium rapidly kills the hosts it infects and is transmitted from host cadavers to new insects by a nematode vector, Steinernema carpocapsae. In order to detect trade-offs in this biological system, we produced 20 bacterial lineages using an experimental evolution protocol. These lineages differ, among other things, in their virulence towards the insect host. We found that nematode parasitic success increases with bacteria virulence, but their survival during dispersal decreases with the number of bacteria they carry. Other bacterial traits, such as production of the haemolytic protein XaxAB, have a strong impact on nematode reproduction. We then combined the result of our measurements with an estimate of bacteria fitness, which was divided into a parasitic component and a dispersal component. Contrary to what was expected in the trade-off hypothesis, we found no significant negative correlation between the two components of bacteria fitness. Still, we found that bacteria fitness is maximized when nematodes carry an intermediate number of cells. Our results therefore demonstrate the existence of a trade-off in X. nematophila, which is caused, in part, by the reduction in survival this bacterium causes to its nematode vectors. PMID:22398163

  6. Genetic basis of destruxin production in the entomopathogen Metarhizium robertsii.

    PubMed

    Giuliano Garisto Donzelli, Bruno; Krasnoff, Stuart B; Moon, Yong-Sun; Sun-Moon, Yong; Churchill, Alice C L; Gibson, Donna M

    2012-04-01

    Destruxins are among the most exhaustively researched secondary metabolites of entomopathogenic fungi, yet definitive evidence for their roles in pathogenicity and virulence has yet to be shown. To establish the genetic bases for the biosynthesis of this family of depsipeptides, we identified a 23,792-bp gene in Metarhizium robertsii ARSEF 2575 containing six complete nonribosomal peptide synthetase modules, with an N-methyltransferase domain in each of the last two modules. This domain arrangement is consistent with the positioning of the adjacent amino acids N-methyl-L: -valine and N-methyl-L: -alanine within the depsipeptide structure of destruxin. DXS expression levels in vitro and in vivo exhibited comparable patterns, beginning at low levels during the early growth phases and increasing with time. Targeted gene knockout using Agrobacterium-mediated transformation produced mutants that failed to synthesize destruxins, in comparison with wild type and ectopic control strains, indicating the involvement of this gene in destruxin biosynthesis. The destruxin synthetase (DXS) disruption mutant was as virulent as the control strain when conidial inoculum was topically applied to larvae of Spodoptera exigua, Galleria mellonella, and Tenebrio molitor indicating that destruxins are dispensable for virulence in these insect hosts. The DXS mutants exhibited no other detectable changes in morphology and development. PMID:22367459

  7. Field trials using the fungal pathogen, Metarhizium anisopliae (Deuteromycetes: Hyphomycetes) to control the ectoparasitic mite, Varroa destructor (Acari: Varroidae) in honey bee, Apis mellifera (Hymenoptera: Apidae) colonies.

    PubMed

    Kanga, Lambert Houssou Ble; Jones, Walker A; James, Rosalind R

    2003-08-01

    The potential for Metarhizium anisopliae (Metschinkoff) to control the parasitic mite, Varroa destructor (Anderson and Trueman) in honey bee colonies was evaluated in field trials against the miticide, tau-fluvalinate (Apistan). Peak mortality of V. destructor occurred 3-4 d after the conidia were applied; however, the mites were still infected 42 d posttreatments. Two application methods were tested: dusts and strips coated with the fungal conidia, and both methods resulted in successful control of mite populations. The fungal treatments were as effective as the Apistan, at the end of the 42-d period of the experiment. The data suggested that optimum mite control could be achieved when no brood is being produced, or when brood production is low, such as in the early spring or late fall. M. anisopliae was harmless to the honey bees (adult bees, or brood) and colony development was not affected. Mite mortality was highly correlated with mycosis in dead mites collected from sticky traps, indicating that the fungus was infecting and killing the mites. Because workers and drones drift between hives, the adult bees were able to spread the fungus between honey bee colonies in the apiary, a situation that could be beneficial to beekeepers. PMID:14503579

  8. Metarhizium anisopliae pathogenesis of mosquito larvae: a verdict of accidental death.

    PubMed

    Butt, Tariq M; Greenfield, Bethany P J; Greig, Carolyn; Maffeis, Thierry G G; Taylor, James W D; Piasecka, Justyna; Dudley, Ed; Abdulla, Ahmed; Dubovskiy, Ivan M; Garrido-Jurado, Inmaculada; Quesada-Moraga, Enrique; Penny, Mark W; Eastwood, Daniel C

    2013-01-01

    Metarhizium anisopliae, a fungal pathogen of terrestrial arthropods, kills the aquatic larvae of Aedes aegypti, the vector of dengue and yellow fever. The fungus kills without adhering to the host cuticle. Ingested conidia also fail to germinate and are expelled in fecal pellets. This study investigates the mechanism by which this fungus adapted to terrestrial hosts kills aquatic mosquito larvae. Genes associated with the M. anisopliae early pathogenic response (proteinases Pr1 and Pr2, and adhesins, Mad1 and Mad2) are upregulated in the presence of larvae, but the established infection process observed in terrestrial hosts does not progress and insecticidal destruxins were not detected. Protease inhibitors reduce larval mortality indicating the importance of proteases in the host interaction. The Ae. aegypti immune response to M. anisopliae appears limited, whilst the oxidative stress response gene encoding for thiol peroxidase is upregulated. Cecropin and Hsp70 genes are downregulated as larval death occurs, and insect mortality appears to be linked to autolysis through caspase activity regulated by Hsp70 and inhibited, in infected larvae, by protease inhibitors. Evidence is presented that a traditional host-pathogen response does not occur as the species have not evolved to interact. M. anisopliae retains pre-formed pathogenic determinants which mediate host mortality, but unlike true aquatic fungal pathogens, does not recognise and colonise the larval host. PMID:24349111

  9. Metarhizium anisopliae Pathogenesis of Mosquito Larvae: A Verdict of Accidental Death

    PubMed Central

    Butt, Tariq M.; Greenfield, Bethany P. J.; Greig, Carolyn; Maffeis, Thierry G. G.; Taylor, James W. D.; Piasecka, Justyna; Dudley, Ed; Abdulla, Ahmed; Dubovskiy, Ivan M.; Garrido-Jurado, Inmaculada; Quesada-Moraga, Enrique; Penny, Mark W.; Eastwood, Daniel C.

    2013-01-01

    Metarhizium anisopliae, a fungal pathogen of terrestrial arthropods, kills the aquatic larvae of Aedes aegypti, the vector of dengue and yellow fever. The fungus kills without adhering to the host cuticle. Ingested conidia also fail to germinate and are expelled in fecal pellets. This study investigates the mechanism by which this fungus adapted to terrestrial hosts kills aquatic mosquito larvae. Genes associated with the M. anisopliae early pathogenic response (proteinases Pr1 and Pr2, and adhesins, Mad1 and Mad2) are upregulated in the presence of larvae, but the established infection process observed in terrestrial hosts does not progress and insecticidal destruxins were not detected. Protease inhibitors reduce larval mortality indicating the importance of proteases in the host interaction. The Ae. aegypti immune response to M. anisopliae appears limited, whilst the oxidative stress response gene encoding for thiol peroxidase is upregulated. Cecropin and Hsp70 genes are downregulated as larval death occurs, and insect mortality appears to be linked to autolysis through caspase activity regulated by Hsp70 and inhibited, in infected larvae, by protease inhibitors. Evidence is presented that a traditional host-pathogen response does not occur as the species have not evolved to interact. M. anisopliae retains pre-formed pathogenic determinants which mediate host mortality, but unlike true aquatic fungal pathogens, does not recognise and colonise the larval host. PMID:24349111

  10. Comparative analysis of the Photorhabdus luminescens and the Yersinia enterocolitica genomes: uncovering candidate genes involved in insect pathogenicity

    PubMed Central

    Heermann, Ralf; Fuchs, Thilo M

    2008-01-01

    Background Photorhabdus luminescens and Yersinia enterocolitica are both enteric bacteria which are associated with insects. P. luminescens lives in symbiosis with soil nematodes and is highly pathogenic towards insects but not to humans. In contrast, Y. enterocolitica is widely found in the environment and mainly known to cause gastroenteritis in men, but has only recently been shown to be also toxic for insects. It is expected that both pathogens share an overlap of genetic determinants that play a role within the insect host. Results A selective genome comparison was applied. Proteins belonging to the class of two-component regulatory systems, quorum sensing, universal stress proteins, and c-di-GMP signalling have been analysed. The interorganismic synopsis of selected regulatory systems uncovered common and distinct signalling mechanisms of both pathogens used for perception of signals within the insect host. Particularly, a new class of LuxR-like regulators was identified, which might be involved in detecting insect-specific molecules. In addition, the genetic overlap unravelled a two-component system that is unique for the genera Photorhabdus and Yersinia and is therefore suggested to play a major role in the pathogen-insect relationship. Our analysis also highlights factors of both pathogens that are expressed at low temperatures as encountered in insects in contrast to higher (body) temperature, providing evidence that temperature is a yet under-investigated environmental signal for bacterial adaptation to various hosts. Common degradative metabolic pathways are described that might be used to explore nutrients within the insect gut or hemolymph, thus enabling the proliferation of P. luminescens and Y. enterocolitica in their invertebrate hosts. A strikingly higher number of genes encoding insecticidal toxins and other virulence factors in P. luminescens compared to Y. enterocolitica correlates with the higher virulence of P. luminescens towards insects

  11. Stress tolerance and virulence of insect-pathogenic fungi are determined by environmental conditions during conidial formation.

    PubMed

    Rangel, Drauzio E N; Braga, Gilberto U L; Fernandes, Éverton K K; Keyser, Chad A; Hallsworth, John E; Roberts, Donald W

    2015-08-01

    The virulence to insects and tolerance to heat and UV-B radiation of conidia of entomopathogenic fungi are greatly influenced by physical, chemical, and nutritional conditions during mycelial growth. This is evidenced, for example, by the stress phenotypes of Metarhizium robertsii produced on various substrates. Conidia from minimal medium (Czapek's medium without sucrose), complex medium, and insect (Lepidoptera and Coleoptera) cadavers had high, moderate, and poor tolerance to UV-B radiation, respectively. Furthermore, conidia from minimal medium germinated faster and had increased heat tolerance and were more virulent to insects than those from complex medium. Low water-activity or alkaline culture conditions also resulted in production of conidia with high tolerance to heat or UV-B radiation. Conidia produced on complex media exhibited lower stress tolerance, whereas those from complex media supplemented with NaCl or KCl (to reduce water activity) were more tolerant to heat and UV-B than those from the unmodified complex medium. Osmotic and nutritive stresses resulted in production of conidia with a robust stress phenotype, but also were associated with low conidial yield. Physical conditions such as growth under illumination, hypoxic conditions, and heat shock before conidial production also induced both higher UV-B and heat tolerance; but conidial production was not decreased. In conclusion, physical and chemical parameters, as well as nutrition source, can induce great variability in conidial tolerance to stress for entomopathogenic fungi. Implications are discussed in relation to the ecology of entomopathogenic fungi in the field, and to their use for biological control. This review will cover recent technologies on improving stress tolerance of entomopathogenic fungi for biological control of insects. PMID:25791499

  12. Vector-Borne Bacterial Plant Pathogens: Interactions with Hemipteran Insects and Plants.

    PubMed

    Perilla-Henao, Laura M; Casteel, Clare L

    2016-01-01

    Hemipteran insects are devastating pests of crops due to their wide host range, rapid reproduction, and ability to transmit numerous plant-infecting pathogens as vectors. While the field of plant-virus-vector interactions has flourished in recent years, plant-bacteria-vector interactions remain poorly understood. Leafhoppers and psyllids are by far the most important vectors of bacterial pathogens, yet there are still significant gaps in our understanding of their feeding behavior, salivary secretions, and plant responses as compared to important viral vectors, such as whiteflies and aphids. Even with an incomplete understanding of plant-bacteria-vector interactions, some common themes have emerged: (1) all known vector-borne bacteria share the ability to propagate in the plant and insect host; (2) particular hemipteran families appear to be incapable of transmitting vector-borne bacteria; (3) all known vector-borne bacteria have highly reduced genomes and coding capacity, resulting in host-dependence; and (4) vector-borne bacteria encode proteins that are essential for colonization of specific hosts, though only a few types of proteins have been investigated. Here, we review the current knowledge on important vector-borne bacterial pathogens, including Xylella fastidiosa, Spiroplasma spp., Liberibacter spp., and 'Candidatus Phytoplasma spp.'. We then highlight recent approaches used in the study of vector-borne bacteria. Finally, we discuss the application of this knowledge for control and future directions that will need to be addressed in the field of vector-plant-bacteria interactions. PMID:27555855

  13. Vector-Borne Bacterial Plant Pathogens: Interactions with Hemipteran Insects and Plants

    PubMed Central

    Perilla-Henao, Laura M.; Casteel, Clare L.

    2016-01-01

    Hemipteran insects are devastating pests of crops due to their wide host range, rapid reproduction, and ability to transmit numerous plant-infecting pathogens as vectors. While the field of plant–virus–vector interactions has flourished in recent years, plant–bacteria–vector interactions remain poorly understood. Leafhoppers and psyllids are by far the most important vectors of bacterial pathogens, yet there are still significant gaps in our understanding of their feeding behavior, salivary secretions, and plant responses as compared to important viral vectors, such as whiteflies and aphids. Even with an incomplete understanding of plant–bacteria–vector interactions, some common themes have emerged: (1) all known vector-borne bacteria share the ability to propagate in the plant and insect host; (2) particular hemipteran families appear to be incapable of transmitting vector-borne bacteria; (3) all known vector-borne bacteria have highly reduced genomes and coding capacity, resulting in host-dependence; and (4) vector-borne bacteria encode proteins that are essential for colonization of specific hosts, though only a few types of proteins have been investigated. Here, we review the current knowledge on important vector-borne bacterial pathogens, including Xylella fastidiosa, Spiroplasma spp., Liberibacter spp., and ‘Candidatus Phytoplasma spp.’. We then highlight recent approaches used in the study of vector-borne bacteria. Finally, we discuss the application of this knowledge for control and future directions that will need to be addressed in the field of vector–plant–bacteria interactions. PMID:27555855

  14. Management of insect-transmitted plant pathogens: defining conditions for successful roguing with a spatially-explicit simulation model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Roguing (the replacement of infected plants with healthy plants) is commonly used to manage the spread of insect-transmitted plant pathogens. Roguing has two potential benefits. First, removing an infected plant eliminates a source of inoculum, potentially slowing pathogen spread. Second, as infe...

  15. Evaluation of Metarhizium anisopliae, Beauveria bassiana and Paecilomyces fumosoroseus as entomopathogens of the cactus moth, Cactoblastis cactorum (Lepidoptera:Pyralidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungal pathogens Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae), Paecilomyces fumosoroseus (Wize) Brown & Smith (Deuteromycotina: Hyphomycetes), and Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Clavicipitaceae) were evaluated as potential biological control ...

  16. Climate change triggers effects of fungal pathogens and insect herbivores on litter decomposition

    NASA Astrophysics Data System (ADS)

    Butenschoen, Olaf; Scheu, Stefan

    2014-10-01

    Increasing infestation by insect herbivores and pathogenic fungi in response to climate change will inevitably impact the amount and quality of leaf litter inputs into the soil. However, little is known on the interactive effect of infestation severity and climate change on litter decomposition, and no such study has been published for deciduous forests in Central Europe. We assessed changes in initial chemical quality of beech (Fagus sylvatica L.) and maple litter (Acer platanoides L.) in response to infestation by the gall midge Mikiola fagi Hart. and the pathogenic fungus Sawadaea tulasnei Fuckel, respectively, and investigated interactive effects of infestation severity, changes in temperature and soil moisture on carbon mineralization in a short-term laboratory study. We found that infestation by the gall midge M. fagi and the pathogenic fungus S. tulasnei significantly changed the chemical quality of beech and maple litter. Changes in element concentrations were generally positive and more pronounced, and if negative less pronounced for maple than beech litter most likely due to high quality fungal tissue remaining on litter after abscission. More importantly, alterations in litter chemical quality did not translate to distinct patterns of carbon mineralization at ambient conditions, but even low amounts of infested litter accelerated carbon mineralization at moderately increased soil moisture and in particular at higher temperature. Our results indicate that insect herbivores and fungal pathogens can markedly alter initial litter chemical quality, but that afterlife effects on carbon mineralization depend on soil moisture and temperature, suggesting that increased infestation severity under projected climate change potentially increases soil carbon release in deciduous forests in Central Europe.

  17. Miro GTPase controls mitochondrial behavior affecting stress tolerance and virulence of a fungal insect pathogen.

    PubMed

    Guan, Yi; Wang, Ding-Yi; Ying, Sheng-Hua; Feng, Ming-Guang

    2016-08-01

    Miro homologues are small mitochondrial Rho GTPases belonging to the Ras superfamily across organisms and are generally unexplored in filamentous fungi. Here we identified a Miro orthologue (bMiro) in Beauveria bassiana, a filamentous fungal insect pathogen as a classic biological control agent of insect pests. This orthologue was proven to anchor on mitochondrial outer membrane in a manner depending completely upon a short C-terminal transmembrane domain. As a result of bmiro deletion, mitochondria in hyphal cells were largely aggregated, and their mass and mobility were reduced, accompanied with a remarkable decrease in ATP content but little change in mitochondrial morphology. The deletion mutant became 42%, 37%, 19% and 10% more tolerant to Ca(2+), Mn(2+), Zn(2+) and Mg(2+) than wild-type, respectively, during cultivation in a minimal medium under normal conditions. The deletion mutant also showed mild defects in conidial germination, vegetative growth, thermotolerance, UV-B resistance and virulence despite null response to oxidative and osmotic stresses. All these phenotypic changes were restored by targeted gene complementation. Our results indicate that bMiro can control mitochondrial distribution and movement required for the transport of ATP-form energy and metal ions and contributes significantly to the fungal potential against insect pests through the control. PMID:27241960

  18. From Insect to Man: Photorhabdus Sheds Light on the Emergence of Human Pathogenicity.

    PubMed

    Mulley, Geraldine; Beeton, Michael L; Wilkinson, Paul; Vlisidou, Isabella; Ockendon-Powell, Nina; Hapeshi, Alexia; Tobias, Nick J; Nollmann, Friederike I; Bode, Helge B; van den Elsen, Jean; ffrench-Constant, Richard H; Waterfield, Nicholas R

    2015-01-01

    Photorhabdus are highly effective insect pathogenic bacteria that exist in a mutualistic relationship with Heterorhabditid nematodes. Unlike other members of the genus, Photorhabdus asymbiotica can also infect humans. Most Photorhabdus cannot replicate above 34°C, limiting their host-range to poikilothermic invertebrates. In contrast, P. asymbiotica must necessarily be able to replicate at 37°C or above. Many well-studied mammalian pathogens use the elevated temperature of their host as a signal to regulate the necessary changes in gene expression required for infection. Here we use RNA-seq, proteomics and phenotype microarrays to examine temperature dependent differences in transcription, translation and phenotype of P. asymbiotica at 28°C versus 37°C, relevant to the insect or human hosts respectively. Our findings reveal relatively few temperature dependant differences in gene expression. There is however a striking difference in metabolism at 37°C, with a significant reduction in the range of carbon and nitrogen sources that otherwise support respiration at 28°C. We propose that the key adaptation that enables P. asymbiotica to infect humans is to aggressively acquire amino acids, peptides and other nutrients from the human host, employing a so called "nutritional virulence" strategy. This would simultaneously cripple the host immune response while providing nutrients sufficient for reproduction. This might explain the severity of ulcerated lesions observed in clinical cases of Photorhabdosis. Furthermore, while P. asymbiotica can invade mammalian cells they must also resist immediate killing by humoral immunity components in serum. We observed an increase in the production of the insect Phenol-oxidase inhibitor Rhabduscin normally deployed to inhibit the melanisation immune cascade. Crucially we demonstrated this molecule also facilitates protection against killing by the alternative human complement pathway. PMID:26681201

  19. Neonicotinoid clothianidin adversely affects insect immunity and promotes replication of a viral pathogen in honey bees.

    PubMed

    Di Prisco, Gennaro; Cavaliere, Valeria; Annoscia, Desiderato; Varricchio, Paola; Caprio, Emilio; Nazzi, Francesco; Gargiulo, Giuseppe; Pennacchio, Francesco

    2013-11-12

    Large-scale losses of honey bee colonies represent a poorly understood problem of global importance. Both biotic and abiotic factors are involved in this phenomenon that is often associated with high loads of parasites and pathogens. A stronger impact of pathogens in honey bees exposed to neonicotinoid insecticides has been reported, but the causal link between insecticide exposure and the possible immune alteration of honey bees remains elusive. Here, we demonstrate that the neonicotinoid insecticide clothianidin negatively modulates NF-κB immune signaling in insects and adversely affects honey bee antiviral defenses controlled by this transcription factor. We have identified in insects a negative modulator of NF-κB activation, which is a leucine-rich repeat protein. Exposure to clothianidin, by enhancing the transcription of the gene encoding this inhibitor, reduces immune defenses and promotes the replication of the deformed wing virus in honey bees bearing covert infections. This honey bee immunosuppression is similarly induced by a different neonicotinoid, imidacloprid, but not by the organophosphate chlorpyriphos, which does not affect NF-κB signaling. The occurrence at sublethal doses of this insecticide-induced viral proliferation suggests that the studied neonicotinoids might have a negative effect at the field level. Our experiments uncover a further level of regulation of the immune response in insects and set the stage for studies on neural modulation of immunity in animals. Furthermore, this study has implications for the conservation of bees, as it will contribute to the definition of more appropriate guidelines for testing chronic or sublethal effects of pesticides used in agriculture. PMID:24145453

  20. From Insect to Man: Photorhabdus Sheds Light on the Emergence of Human Pathogenicity

    PubMed Central

    Mulley, Geraldine; Beeton, Michael L.; Wilkinson, Paul; Vlisidou, Isabella; Ockendon-Powell, Nina; Hapeshi, Alexia; Tobias, Nick J.; Nollmann, Friederike I.; Bode, Helge B.; van den Elsen, Jean; ffrench-Constant, Richard H.; Waterfield, Nicholas R.

    2015-01-01

    Photorhabdus are highly effective insect pathogenic bacteria that exist in a mutualistic relationship with Heterorhabditid nematodes. Unlike other members of the genus, Photorhabdus asymbiotica can also infect humans. Most Photorhabdus cannot replicate above 34°C, limiting their host-range to poikilothermic invertebrates. In contrast, P. asymbiotica must necessarily be able to replicate at 37°C or above. Many well-studied mammalian pathogens use the elevated temperature of their host as a signal to regulate the necessary changes in gene expression required for infection. Here we use RNA-seq, proteomics and phenotype microarrays to examine temperature dependent differences in transcription, translation and phenotype of P. asymbiotica at 28°C versus 37°C, relevant to the insect or human hosts respectively. Our findings reveal relatively few temperature dependant differences in gene expression. There is however a striking difference in metabolism at 37°C, with a significant reduction in the range of carbon and nitrogen sources that otherwise support respiration at 28°C. We propose that the key adaptation that enables P. asymbiotica to infect humans is to aggressively acquire amino acids, peptides and other nutrients from the human host, employing a so called “nutritional virulence” strategy. This would simultaneously cripple the host immune response while providing nutrients sufficient for reproduction. This might explain the severity of ulcerated lesions observed in clinical cases of Photorhabdosis. Furthermore, while P. asymbiotica can invade mammalian cells they must also resist immediate killing by humoral immunity components in serum. We observed an increase in the production of the insect Phenol-oxidase inhibitor Rhabduscin normally deployed to inhibit the melanisation immune cascade. Crucially we demonstrated this molecule also facilitates protection against killing by the alternative human complement pathway. PMID:26681201

  1. First unusual case of keratitis in Europe due to the rare fungus Metarhizium anisopliae.

    PubMed

    Dorin, Josephine; Debourgogne, Anne; Zaïdi, Mohamed; Bazard, Marie-Christine; Machouart, Marie

    2015-05-01

    Metarhizium anisopliae is a fungus utilized worldwide for insect-pest biocontrol. Few M. anisopliae infections have been reported previously. Here, M. anisopliae was isolated from a corneal ulcer in a healthy man. It is the first ocular case in France and Europe of this extremely rare fungus in humans. PMID:25813244

  2. Production of microsclerotia of the entomopathogenic fungus Metarhizium anisopliae in liquid culture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this study was the development of a liquid culture method for producing stable, infective propagules of the entomopathogenic fungus Metarhizium anisopliae for control of soil-dwelling insect pests. Three strains of M. anisopliae, F52, TM109, and MA1200, were evaluated using aerated, liq...

  3. Metabolomics reveals the heterogeneous secretome of two entomopathogenic fungi to ex vivo cultured insect tissues.

    PubMed

    de Bekker, Charissa; Smith, Philip B; Patterson, Andrew D; Hughes, David P

    2013-01-01

    Fungal entomopathogens rely on cellular heterogeneity during the different stages of insect host infection. Their pathogenicity is exhibited through the secretion of secondary metabolites, which implies that the infection life history of this group of environmentally important fungi can be revealed using metabolomics. Here metabolomic analysis in combination with ex vivo insect tissue culturing shows that two generalist isolates of the genus Metarhizium and Beauveria, commonly used as biological pesticides, employ significantly different arrays of secondary metabolites during infectious and saprophytic growth. It also reveals that both fungi exhibit tissue specific strategies by a distinguishable metabolite secretion on the insect tissues tested in this study. In addition to showing the important heterogeneous nature of these two entomopathogens, this study also resulted in the discovery of several novel destruxins and beauverolides that have not been described before, most likely because previous surveys did not use insect tissues as a culturing system. While Beauveria secreted these cyclic depsipeptides when encountering live insect tissues, Metarhizium employed them primarily on dead tissue. This implies that, while these fungi employ comparable strategies when it comes to entomopathogenesis, there are most certainly significant differences at the molecular level that deserve to be studied. PMID:23940603

  4. Metabolomics Reveals the Heterogeneous Secretome of Two Entomopathogenic Fungi to Ex Vivo Cultured Insect Tissues

    PubMed Central

    de Bekker, Charissa; Smith, Philip B.; Patterson, Andrew D.; Hughes, David P.

    2013-01-01

    Fungal entomopathogens rely on cellular heterogeneity during the different stages of insect host infection. Their pathogenicity is exhibited through the secretion of secondary metabolites, which implies that the infection life history of this group of environmentally important fungi can be revealed using metabolomics. Here metabolomic analysis in combination with ex vivo insect tissue culturing shows that two generalist isolates of the genus Metarhizium and Beauveria, commonly used as biological pesticides, employ significantly different arrays of secondary metabolites during infectious and saprophytic growth. It also reveals that both fungi exhibit tissue specific strategies by a distinguishable metabolite secretion on the insect tissues tested in this study. In addition to showing the important heterogeneous nature of these two entomopathogens, this study also resulted in the discovery of several novel destruxins and beauverolides that have not been described before, most likely because previous surveys did not use insect tissues as a culturing system. While Beauveria secreted these cyclic depsipeptides when encountering live insect tissues, Metarhizium employed them primarily on dead tissue. This implies that, while these fungi employ comparable strategies when it comes to entomopathogenesis, there are most certainly significant differences at the molecular level that deserve to be studied. PMID:23940603

  5. Heat-induced post-stress growth delay: a biological trait of many Metarhizium isolates reducing biocontrol efficacy?

    PubMed

    Keyser, Chad A; Fernandes, Éverton K K; Rangel, Drauzio E N; Roberts, Donald W

    2014-07-01

    The habitats of many pest insects have fluctuating climatic conditions. To function effectively, the pathogens of these pests must be capable of infecting and developing disease at a wide range of temperatures. The current study examines ten Metarhizium spp. isolates as to their ability to recover normal metabolic activity after exposure to high temperature for several hours daily; and whether such recovery, with at least some isolates, requires a temporary repair ("retooling") period. Fungal colonies were exposed to 40°C for 4h or 8h followed by 20h or 16h at 28°C, respectively, for three consecutive days. Growth rates during treatments were compared to control plates (constant 28°C) and to plates with growth stoppage by cold treatment (4h or 8h at 5°C per day). All ten isolates survived 3days of cycled heat treatment and resumed normal growth afterward; some isolates however, were considerably more negatively affected by heat-cycling than others. In fact, some isolates underwent greatly reduced growth not only during 8h heating, but also some hours after cessation of heat treatment. This phenomenon is labeled in the current study as "post-stress growth delay" (PSGD). In contrast, all isolates stopped growing during 8h cold treatments, but immediately recommenced growing on return to 28°C. The delay in recommencing growth of some isolates after heat treatment amplifies the effect of this stress. In addition to the studies on the effects of heat cycling on fungal cultures, the effects of imposing such temperature cycling on fungal infection of insects was documented in the laboratory. Three Metarhizium isolates were bioassayed using Galleria mellonella larvae. Treated insects were placed at daily temperature regimes matching those used for the in vitro fungus rate-of-growth study, and insect mortality recorded daily. For all three isolates the levels of insect mortality at the highest-heat dose (40°C at 8h daily) significantly reduced infection. Fluctuating

  6. Trade-offs and mixed infections in an obligate-killing insect pathogen.

    PubMed

    Redman, Elizabeth M; Wilson, Kenneth; Cory, Jenny S

    2016-09-01

    Natural populations of pathogens are frequently composed of numerous interacting strains. Understanding what maintains this diversity remains a key focus of research in disease ecology. In addition, within-host pathogen dynamics can have a strong impact on both infection outcome and the evolution of pathogen virulence, and thus, understanding the impact of pathogen diversity is important for disease management. We compared eight genetically distinguishable variants from Spodoptera exempta nucleopolyhedrovirus (SpexNPV) isolated from the African armyworm, Spodoptera exempta. NPVs are obligate killers, and the vast majority of transmission stages are not released until after the host has died. The NPV variants differed significantly in their virulence and could be clustered into two groups based on their dose-response curves. They also differed in their speed of kill and productivity (transmission potential) for S. exempta. The mixed-genotype wild-type (WT) SpexNPV, from which each variant was isolated, was significantly more virulent than any individual variant and its mean mortality rate was within the fastest group of individual variants. However, the WT virus produced fewer new infectious stages than any single variant, which might reflect competition among the variants. A survival analysis, combining the mortality and speed of kill data, confirmed the superiority of the genetically mixed WT virus over any single variant. Spodoptera exempta larvae infected with WT SpexNPV were predicted to die 2·7 and 1·9 times faster than insects infected with isolates from either of the two clusters of genotypes. Theory suggests that there are likely to be trade-offs between pathogen fitness traits. Across all larvae, there was a negative linear relationship between virus yield and speed of kill, such that more rapid host death carried the cost of producing fewer transmission stages. We also found a near-significant relationship for the same trend at the intervariant level

  7. Advances in microbial insect control in horticultural ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of microbial organisms as biological control agents has progressed significantly since Metschnikoff launched the first attempt at microbial insect control with Metarhizium anisopliae in 1879. Following the lead of Metschnikoff, entomopathogenic nematodes, fungi, bacteria and viruses have b...

  8. Domain Shuffling in a Sensor Protein Contributed to the Evolution of Insect Pathogenicity in Plant-Beneficial Pseudomonas protegens

    PubMed Central

    Kupferschmied, Peter; Péchy-Tarr, Maria; Imperiali, Nicola; Maurhofer, Monika; Keel, Christoph

    2014-01-01

    Pseudomonas protegens is a biocontrol rhizobacterium with a plant-beneficial and an insect pathogenic lifestyle, but it is not understood how the organism switches between the two states. Here, we focus on understanding the function and possible evolution of a molecular sensor that enables P. protegens to detect the insect environment and produce a potent insecticidal toxin specifically during insect infection but not on roots. By using quantitative single cell microscopy and mutant analysis, we provide evidence that the sensor histidine kinase FitF is a key regulator of insecticidal toxin production. Our experimental data and bioinformatic analyses indicate that FitF shares a sensing domain with DctB, a histidine kinase regulating carbon uptake in Proteobacteria. This suggested that FitF has acquired its specificity through domain shuffling from a common ancestor. We constructed a chimeric DctB-FitF protein and showed that it is indeed functional in regulating toxin expression in P. protegens. The shuffling event and subsequent adaptive modifications of the recruited sensor domain were critical for the microorganism to express its potent insect toxin in the observed host-specific manner. Inhibition of the FitF sensor during root colonization could explain the mechanism by which P. protegens differentiates between the plant and insect host. Our study establishes FitF of P. protegens as a prime model for molecular evolution of sensor proteins and bacterial pathogenicity. PMID:24586167

  9. Characterization of an Insecticidal Toxin and Pathogenicity of Pseudomonas taiwanensis against Insects

    PubMed Central

    Chen, Wen-Jen; Hsieh, Feng-Chia; Hsu, Fu-Chiun; Tasy, Yi-Fang; Liu, Je-Ruei; Shih, Ming-Che

    2014-01-01

    Pseudomonas taiwanensis is a broad-host-range entomopathogenic bacterium that exhibits insecticidal activity toward agricultural pests Plutella xylostella, Spodoptera exigua, Spodoptera litura, Trichoplusia ni and Drosophila melanogaster. Oral infection with different concentrations (OD = 0.5 to 2) of wild-type P. taiwanensis resulted in insect mortality rates that were not significantly different (92.7%, 96.4% and 94.5%). The TccC protein, a component of the toxin complex (Tc), plays an essential role in the insecticidal activity of P. taiwanensis. The ΔtccC mutant strain of P. taiwanensis, which has a knockout mutation in the tccC gene, only induced 42.2% mortality in P. xylostella, even at a high bacterial dose (OD = 2.0). TccC protein was cleaved into two fragments, an N-terminal fragment containing an Rhs-like domain and a C-terminal fragment containing a Glt symporter domain and a TraT domain, which might contribute to antioxidative stress activity and defense against macrophagosis, respectively. Interestingly, the primary structure of the C-terminal region of TccC in P. taiwanensis is unique among pathogens. Membrane localization of the C-terminal fragment of TccC was proven by flow cytometry. Sonicated pellets of P. taiwanensis ΔtccC strain had lower toxicity against the Sf9 insect cell line and P. xylostella larvae than the wild type. We also found that infection of Sf9 and LD652Y-5d cell lines with P. taiwanensis induced apoptotic cell death. Further, natural oral infection by P. taiwanensis triggered expression of host programmed cell death-related genes JNK-2 and caspase-3. PMID:25144637

  10. Inducible expression of a fusion gene encoding two proteinase inhibitors leads to insect and pathogen resistance in transgenic rice.

    PubMed

    Quilis, Jordi; López-García, Belén; Meynard, Donaldo; Guiderdoni, Emmanuel; San Segundo, Blanca

    2014-04-01

    Plant proteinase inhibitors (PIs) are considered as candidates for increased insect resistance in transgenic plants. Insect adaptation to PI ingestion might, however, compromise the benefits received by transgenic expression of PIs. In this study, the maize proteinase inhibitor (MPI), an inhibitor of insect serine proteinases, and the potato carboxypeptidase inhibitor (PCI) were fused into a single open reading frame and introduced into rice plants. The two PIs were linked using either the processing site of the Bacillus thuringiensis Cry1B precursor protein or the 2A sequence from the foot-and-mouth disease virus (FMDV). Expression of each fusion gene was driven by the wound- and pathogen-inducible mpi promoter. The mpi-pci fusion gene was stably inherited for at least three generations with no penalty on plant phenotype. An important reduction in larval weight of Chilo suppressalis fed on mpi-pci rice, compared with larvae fed on wild-type plants, was observed. Expression of the mpi-pci fusion gene confers resistance to C. suppressalis (striped stem borer), one of the most important insect pest of rice. The mpi-pci expression systems described may represent a suitable strategy for insect pest control, better than strategies based on the use of single PI genes, by preventing insect adaptive responses. The rice plants expressing the mpi-pci fusion gene also showed enhanced resistance to infection by the fungus Magnaporthe oryzae, the causal agent of the rice blast disease. Our results illustrate the usefulness of the inducible expression of the mpi-pci fusion gene for dual resistance against insects and pathogens in rice plants. PMID:24237606

  11. Fungal dimorphism in the entomopathogenic fungus Metarhizium rileyi: Detection of an in vivo quorum-sensing system.

    PubMed

    Boucias, D; Liu, S; Meagher, R; Baniszewski, J

    2016-05-01

    This investigation documents the expression of the in vivo dimorphic program exhibited by the insect mycopathogen Metarhizium rileyi. This insect mycopathogen represents the key mortality factor regulating various caterpillar populations in legumes, including subtropical and tropical soybeans. Using two hosts and M. rileyi isolates, we have measured M. rileyi growth rates under in vivo and in vitro conditions and have assessed the pathogen's impact on host fitness. Significantly, the hyphal bodies-to-mycelia transition that occurs at the late infection stage is regulated by a quorum-sensing molecule(s) (QSM) that triggers hyphal bodies (Hb) to synchronously switch to the tissue-invasive mycelia. Within hours of this transition, the host insect succumbs to mycosis. The production of the QS chemical(s) occurs when a quorum of Hb is produced in the hemolymph (late-stage infection). Furthermore, the QS activity detected in late-stage infected sera is unique and is unrelated to any known fungal QSM. The lack of similar QS activity from conditioned media of M. rileyi suggests that the chemical signal(s) that mediates the dimorphic switch is produced by host tissues in response to a quorum of hyphal bodies produced in the host hemolymph. The serum-based QS activity is retained after lyophilization, mild heat treatment, and proteinase digestion. However, attempts to extract/identify the QSM have been unsuccessful. Results suggest that the observed hyphal body-to-mycelia transition is a multi-step process involving more than one chemical signal. PMID:27018146

  12. Insect immunity: oral exposure to a bacterial pathogen elicits free radical response and protects from a recurring infection

    PubMed Central

    2014-01-01

    Background Previous exposure to a pathogen can help organisms cope with recurring infection. This is widely recognised in vertebrates, but increasing occasions are also being reported in invertebrates where this phenomenon is referred to as immune priming. However, the mechanisms that allow acquired pathogen resistance in insects remain largely unknown. Results We studied the priming of bacterial resistance in the larvae of the tiger moth, Parasemia plantaginis using two gram-negative bacteria, a pathogenic Serratia marcescens and a non-pathogenic control, Escherichia coli. A sublethal oral dose of S. marcescens provided the larvae with effective protection against an otherwise lethal septic infection with the same pathogen five days later. At the same time, we assessed three anti-bacterial defence mechanisms from the larvae that had been primarily exposed to the bacteria via contaminated host plant. Results showed that S. marcescens had induced a higher amount of reactive oxygen species (ROS) in the larval haemolymph, possibly protecting the host from the recurring infection. Conclusions Our study supports the growing evidence of immune priming in insects. It shows that activation of the protective mechanism requires a specific induction, rather than a sheer exposure to any gram-negative bacteria. The findings indicate that systemic pathogen recognition happens via the gut, and suggest that persistent loitering of immune elicitors or anti-microbial molecules are a possible mechanism for the observed prophylaxis. The self-harming effects of ROS molecules are well known, which indicates a potential cost of increased resistance. Together these findings could have important implications on the ecological and epidemiological processes affecting insect and pathogen populations. PMID:24602309

  13. THE PESTICIDE METARHIZIUM ANISOPLIAE HAS AN ADJUVANT EFFECT ON THE ALLERGIC RESPONSE TO OVALBUMIN IN MICE

    EPA Science Inventory

    Metarhizium anisopliae is a parasitic fungus employed as a biological control agent against vermin and used in the US for indoor control of cockroaches. Sensitization to cockroach allergens is associated with development of asthma. This pesticide is non-pathogenic for humans and ...

  14. Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality.

    PubMed

    Alkhaibari, Abeer M; Carolino, Aline T; Yavasoglu, Sare I; Maffeis, Thierry; Mattoso, Thalles C; Bull, James C; Samuels, Richard I; Butt, Tariq M

    2016-07-01

    Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world's population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti larvae

  15. Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality

    PubMed Central

    Alkhaibari, Abeer M.; Carolino, Aline T.; Yavasoglu, Sare I.; Maffeis, Thierry; Mattoso, Thalles C.; Bull, James C.; Samuels, Richard I.; Butt, Tariq M.

    2016-01-01

    Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world’s population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti

  16. Pathogen persistence in the environment and insect-baculovirus interactions: disease-density thresholds, epidemic burnout, and insect outbreaks.

    PubMed

    Fuller, Emma; Elderd, Bret D; Dwyer, Greg

    2012-03-01

    Classical epidemic theory focuses on directly transmitted pathogens, but many pathogens are instead transmitted when hosts encounter infectious particles. Theory has shown that for such diseases pathogen persistence time in the environment can strongly affect disease dynamics, but estimates of persistence time, and consequently tests of the theory, are extremely rare. We consider the consequences of persistence time for the dynamics of the gypsy moth baculovirus, a pathogen transmitted when larvae consume foliage contaminated with particles released from infectious cadavers. Using field-transmission experiments, we are able to estimate persistence time under natural conditions, and inserting our estimates into a standard epidemic model suggests that epidemics are often terminated by a combination of pupation and burnout rather than by burnout alone, as predicted by theory. Extending our models to allow for multiple generations, and including environmental transmission over the winter, suggests that the virus may survive over the long term even in the absence of complex persistence mechanisms, such as environmental reservoirs or covert infections. Our work suggests that estimates of persistence times can lead to a deeper understanding of environmentally transmitted pathogens and illustrates the usefulness of experiments that are closely tied to mathematical models. PMID:22322229

  17. Pathogen Persistence in the Environment and Insect-Baculovirus Interactions: Disease-Density Thresholds, Epidemic Burnout and Insect Outbreaks

    PubMed Central

    Fuller, Emma; Elderd, Bret D.

    2013-01-01

    Classical epidemic theory focuses on directly transmitted pathogens, but many pathogens are instead transmitted when hosts encounter infectious particles. Theory has shown that for such diseases pathogen persistence time in the environment can strongly affect disease dynamics, but estimates of persistence time, and consequently tests of the theory, are extremely rare. We consider the consequences of persistence time for the dynamics of the gypsy moth baculovirus, a pathogen transmitted when larvae consume foliage contaminated with particles released from infectious cadavers. Using field-transmission experiments, we are able to estimate persistence time under natural conditions, and inserting our estimates into a standard epidemic model suggests that epidemics are often terminated by a combination of pupation and burnout, rather than by burnout alone as predicted by theory. Extending our models to allow for multiple generations, and including environmental transmission over the winter, suggests that the virus may survive over the long term even in the absence of complex persistence mechanisms, such as environmental reservoirs or covert infections. Our work suggests that estimates of persistence times can lead to a deeper understanding of environmentally transmitted pathogens, and illustrates the usefulness of experiments that are closely tied to mathematical models. PMID:22322229

  18. Multiplexed microsatellite markers for seven Metarhizium species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cross-species transferability of 41 previously published simple sequence repeat (SSR) markers was assessed for 11 species of the entomopathogenic fungus Metarhizium. A collection of 65 Metarhizium isolates including all 54 used in a recent phylogenetic revision of the genus were characterized. Betwe...

  19. Susceptibility of Adults of the Cerambycid Beetle Hedypathes betulinus to the Entomopathogenic Fungi Beauveria bassiana, Metarhizium anisopliae, and Purpureocillium Lilacinum

    PubMed Central

    Schapovaloff, M. E.; Alves, L. F. A.; Fanti, A. L.; Alzogaray, R. A.; Lastra, C. C. López

    2014-01-01

    The cerambycid beetle Hedypathes betulinus (Klug) (Coleoptera: Cerambycidae) causes severe damage to yerba mate plants (Ilex paraguariensis (St. Hilaire) (Aquifoliales: Aquifoliaceae)), which results in large losses of production. In this study, the pathogenicity of entomopathogenic fungi of the species Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitaceae), Metarhizium anisopliae sensu lato (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae), and Purpureocillium lilacinum (Thom) Luangsa-ard, Hywel-Jones, Houbraken and Samson (Hypocreales: Ophiocordycipitaceae) on yerba mate were evaluated. Fifteen isolates of B. bassiana, two of M. anisopliae, and seven of P. lilacinum on H. betulinus adults were analyzed under laboratory conditions. The raw mortality rate caused by B. bassiana isolates varied from 51.1 to 86.3%, and their LT50 values varied between 8.7 and 13.6 d. The isolates of M. anisopliae caused 69.6–81.8% mortality, and their LT50 values varied between 7.4 and 7.9 d. In contrast, isolates of P. lilacinum were not pathogenic. M. anisopliae and B. bassiana isolates were pathogenic against H. betulinus adults, suggesting that they may be useful in biological control programs for insect pests of yerba mate. PMID:25368071

  20. Induced plant defenses, host-pathogen interactions, and forest insect outbreaks.

    PubMed

    Elderd, Bret D; Rehill, Brian J; Haynes, Kyle J; Dwyer, Greg

    2013-09-10

    Cyclic outbreaks of defoliating insects devastate forests, but their causes are poorly understood. Outbreak cycles are often assumed to be driven by density-dependent mortality due to natural enemies, because pathogens and predators cause high mortality and because natural-enemy models reproduce fluctuations in defoliation data. The role of induced defenses is in contrast often dismissed, because toxic effects of defenses are often weak and because induced-defense models explain defoliation data no better than natural-enemy models. Natural-enemy models, however, fail to explain gypsy moth outbreaks in North America, in which outbreaks in forests with a higher percentage of oaks have alternated between severe and mild, whereas outbreaks in forests with a lower percentage of oaks have been uniformly moderate. Here we show that this pattern can be explained by an interaction between induced defenses and a natural enemy. We experimentally induced hydrolyzable-tannin defenses in red oak, to show that induction reduces variability in a gypsy moth's risk of baculovirus infection. Because this effect can modulate outbreak severity and because oaks are the only genus of gypsy moth host tree that can be induced, we extended a natural-enemy model to allow for spatial variability in inducibility. Our model shows alternating outbreaks in forests with a high frequency of oaks, and uniform outbreaks in forests with a low frequency of oaks, matching the data. The complexity of this effect suggests that detecting effects of induced defenses on defoliator cycles requires a combination of experiments and models. PMID:23966566

  1. Sexual Transmission of a Plant Pathogenic Bacterium, Candidatus Liberibacter asiaticus, between Conspecific Insect Vectors during Mating

    PubMed Central

    Mann, Rajinder S.; Pelz-Stelinski, Kirsten; Hermann, Sara L.; Tiwari, Siddharth; Stelinski, Lukasz L.

    2011-01-01

    Candidatus Liberibacter asiaticus is a fastidious, phloem-inhabiting, gram-negative bacterium transmitted by Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). The bacterium is the presumed causal agent of huanglongbing (HLB), one of the most destructive and economically important diseases of citrus. We investigated whether Las is transmitted between infected and uninfected D. citri adults during courtship. Our results indicate that Las was sexually transmitted from Las-infected male D. citri to uninfected females at a low rate (<4%) during mating. Sexual transmission was not observed following mating of infected females and uninfected males or among adult pairs of the same sex. Las was detected in genitalia of both sexes and also in eggs of infected females. A latent period of 7 days or more was required to detect the bacterium in recipient females. Rod shaped as well as spherical structures resembling Las were observed in ovaries of Las-infected females with transmission electron microscopy, but were absent in ovaries from uninfected D. citri females. The size of the rod shaped structures varied from 0.39 to 0.67 µm in length and 0.19 to 0.39 µm in width. The spherical structures measured from 0.61 to 0.80 µm in diameter. This investigation provides convincing evidence that a plant pathogenic bacterium is sexually transmitted from male to female insects during courtship and established evidence that bacteria persist in reproductive organs. Moreover, these findings provide an alternative sexually horizontal mechanism for the spread of Las within populations of D. citri, even in the absence of infected host trees. PMID:22216209

  2. Induced plant defenses, host–pathogen interactions, and forest insect outbreaks

    PubMed Central

    Elderd, Bret D.; Rehill, Brian J.; Haynes, Kyle J.; Dwyer, Greg

    2013-01-01

    Cyclic outbreaks of defoliating insects devastate forests, but their causes are poorly understood. Outbreak cycles are often assumed to be driven by density-dependent mortality due to natural enemies, because pathogens and predators cause high mortality and because natural-enemy models reproduce fluctuations in defoliation data. The role of induced defenses is in contrast often dismissed, because toxic effects of defenses are often weak and because induced-defense models explain defoliation data no better than natural-enemy models. Natural-enemy models, however, fail to explain gypsy moth outbreaks in North America, in which outbreaks in forests with a higher percentage of oaks have alternated between severe and mild, whereas outbreaks in forests with a lower percentage of oaks have been uniformly moderate. Here we show that this pattern can be explained by an interaction between induced defenses and a natural enemy. We experimentally induced hydrolyzable-tannin defenses in red oak, to show that induction reduces variability in a gypsy moth’s risk of baculovirus infection. Because this effect can modulate outbreak severity and because oaks are the only genus of gypsy moth host tree that can be induced, we extended a natural-enemy model to allow for spatial variability in inducibility. Our model shows alternating outbreaks in forests with a high frequency of oaks, and uniform outbreaks in forests with a low frequency of oaks, matching the data. The complexity of this effect suggests that detecting effects of induced defenses on defoliator cycles requires a combination of experiments and models. PMID:23966566

  3. Overexpression of a Metarhizium robertsii HSP25 gene increases thermotolerance and survival in soil.

    PubMed

    Liao, Xinggang; Lu, Hsiao-Ling; Fang, Weiguo; St Leger, Raymond J

    2014-01-01

    Temperature extremes are an important adverse factor limiting the effectiveness of microbial pest control agents. They reduce virulence and persistence in the plant root-colonizing insect pathogen Metarhizium robertsii. Small heat shock proteins have been shown to confer thermotolerance in many organisms. In this study, we report on the cloning and characterization of a small heat shock protein gene hsp25 from M. robertsii. hsp25 expression was upregulated when the fungus was grown at extreme temperatures (4, 35, and 42 °C) or in the presence of oxidative or osmotic agents. Expression of hsp25 in Escherichia coli increased bacterial thermotolerance confirming that hsp25 encodes a functional heat shock protein. Overexpressing hsp25 in M. robertsii increased fungal growth under heat stress either in nutrient-rich medium or on locust wings and enhanced the tolerance of heat shock-treated conidia to osmotic stress. In addition, overexpression of hsp25 increased the persistence of M. robertsii in rhizospheric soils in outdoor microcosms, though it did not affect survival in bulk soil, indicating that M. robertsii's survival in soil is dependent on interactions with plant roots. PMID:24265026

  4. Unveiling chemical defense in the rice stalk stink bug against the entomopathogenic fungus Metarhizium anisopliae.

    PubMed

    da Silva, Rodrigo Alves; Quintela, Eliane Dias; Mascarin, Gabriel Moura; Pedrini, Nicolás; Lião, Luciano Moraes; Ferri, Pedro Henrique

    2015-05-01

    Eggs, nymphs (1st-5th instar) and adults of Tibraca limbativentris were challenged by conidial suspensions of its major fungal pathogen Metarhizium anisopliae in order to assess their susceptibility. The role of chemical defensive compounds from exocrine secretions produced by both nymphs and adults were examined for their participation on M. anisopliae infection. Although insect susceptibility to M. anisopliae followed a dose-dependent manner, adults followed by older nymphs displayed the highest resistance. Eggs were highly susceptible showing >96% fungal infection. Crude extracts isolated from metathoracic scent gland and dorsal abdominal glands of adults and nymphs, respectively, showed fungistatic effects by impairing spore germination, vegetative growth and sporulation. Gas chromatography-mass spectrometry analysis of these extracts revealed that the major components were short-chain hydrocarbons (C10-13) and unsaturated aldehydes. In vitro tests with the corresponding synthetic standards indicated compounds with greater antifungal activity including (E)-2-hexenal, (E)-2-octenal, and (E)-2-decenal, with the latter being the most deleterious to fungal fitness. We demonstrated that differential susceptibility of the rice stalk stink bug to M. anisopliae infection is age-specific and partly mediated by fungistatic properties of aldehydes, which are produced by scent glands of both nymphs and adults. PMID:25805519

  5. Disruption of Vector Host Preference with Plant Volatiles May Reduce Spread of Insect-Transmitted Plant Pathogens.

    PubMed

    Martini, Xavier; Willett, Denis S; Kuhns, Emily H; Stelinski, Lukasz L

    2016-05-01

    Plant pathogens can manipulate the odor of their host; the odor of an infected plant is often attractive to the plant pathogen vector. It has been suggested that this odor-mediated manipulation attracts vectors and may contribute to spread of disease; however, this requires further broad demonstration among vector-pathogen systems. In addition, disruption of this indirect chemical communication between the pathogen and the vector has not been attempted. We present a model that demonstrates how a phytophathogen (Candidatus Liberibacter asiaticus) can increase its spread by indirectly manipulating the behavior of its vector (Asian citrus psyllid, Diaphorina citri Kuwayama). The model indicates that when vectors are attracted to pathogen-infected hosts, the proportion of infected vectors increases, as well as, the proportion of infected hosts. Additionally, the peak of infected host populations occurs earlier as compared with controls. These changes in disease dynamics were more important during scenarios with higher vector mortality. Subsequently, we conducted a series of experiments to disrupt the behavior of the Asian citrus psyllid. To do so, we exposed the vector to methyl salicylate, the major compound released following host infection with the pathogen. We observed that during exposure or after pre-exposure to methyl salicylate, the host preference can be altered; indeed, the Asian citrus psyllids were unable to select infected hosts over uninfected counterparts. We suggest mechanisms to explain these interactions and potential applications of disrupting herbivore host preference with plant volatiles for sustainable management of insect vectors. PMID:27193763

  6. Glycerol-3-Phosphate Acyltransferase Contributes to Triacylglycerol Biosynthesis, Lipid Droplet Formation, and Host Invasion in Metarhizium robertsii

    PubMed Central

    Gao, Qiang; Shang, Yanfang; Huang, Wei

    2013-01-01

    Enzymes involved in the triacylglycerol (TAG) biosynthesis have been well studied in the model organisms of yeasts and animals. Among these, the isoforms of glycerol-3-phosphate acyltransferase (GPAT) redundantly catalyze the first and rate-limiting step in glycerolipid synthesis. Here, we report the functions of mrGAT, a GPAT ortholog, in an insect-pathogenic fungus, Metarhizium robertsii. Unlike in yeasts and animals, a single copy of the mrGAT gene is present in the fungal genome and the gene deletion mutant is viable. Compared to the wild type and the gene-rescued mutant, the ΔmrGAT mutant demonstrated reduced abilities to produce conidia and synthesize TAG, glycerol, and total lipids. More importantly, we found that mrGAT is localized to the endoplasmic reticulum and directly linked to the formation of lipid droplets (LDs) in fungal cells. Insect bioassay results showed that mrGAT is required for full fungal virulence by aiding fungal penetration of host cuticles. Data from this study not only advance our understanding of GPAT functions in fungi but also suggest that filamentous fungi such as M. robertsii can serve as a good model to elucidate the role of the glycerol phosphate pathway in fungal physiology, particularly to determine the mechanistic connection of GPAT to LD formation. PMID:24077712

  7. Terpene down-regulation in orange reveals the role of fruit aromas in mediating interactions with insect herbivores and pathogens.

    PubMed

    Rodríguez, Ana; San Andrés, Victoria; Cervera, Magdalena; Redondo, Ana; Alquézar, Berta; Shimada, Takehiko; Gadea, José; Rodrigo, María Jesús; Zacarías, Lorenzo; Palou, Lluís; López, María M; Castañera, Pedro; Peña, Leandro

    2011-06-01

    Plants use volatile terpene compounds as odor cues for communicating with the environment. Fleshy fruits are particularly rich in volatiles that deter herbivores and attract seed dispersal agents. We have investigated how terpenes in citrus fruit peels affect the interaction between the plant, insects, and microorganisms. Because limonene represents up to 97% of the total volatiles in orange (Citrus sinensis) fruit peel, we chose to down-regulate the expression of a limonene synthase gene in orange plants by introducing an antisense construct of this gene. Transgenic fruits showed reduced accumulation of limonene in the peel. When these fruits were challenged with either the fungus Penicillium digitatum or with the bacterium Xanthomonas citri subsp. citri, they showed marked resistance against these pathogens that were unable to infect the peel tissues. Moreover, males of the citrus pest medfly (Ceratitis capitata) were less attracted to low limonene-expressing fruits than to control fruits. These results indicate that limonene accumulation in the peel of citrus fruit appears to be involved in the successful trophic interaction between fruits, insects, and microorganisms. Terpene down-regulation might be a strategy to generate broad-spectrum resistance against pests and pathogens in fleshy fruits from economically important crops. In addition, terpene engineering may be important for studying the basic ecological interactions between fruits, herbivores, and pathogens. PMID:21525333

  8. Root isolations of Metarhizium spp. from crops reflect diversity in the soil and indicate no plant specificity.

    PubMed

    Steinwender, Bernhardt M; Enkerli, Jürg; Widmer, Franco; Eilenberg, Jørgen; Kristensen, Hanne L; Bidochka, Michael J; Meyling, Nicolai V

    2015-11-01

    Metarhizium spp. have recently been shown to be associated with the roots of different plants. Here we evaluated which Metarhizium species were associated with roots of oat (Avena sativa), rye (Secale cereale) and cabbage (Brassica oleracea), common crop plants in Denmark. Thirty-six root samples from each of the three crops were collected within an area of approximately 3ha. The roots were rinsed with sterile water, homogenized and the homogenate plated onto selective media. A subset of 126 Metarhizium isolates were identified to species by sequencing of the 5' end of the gene translation elongation factor 1-alpha and characterized by simple sequence repeat (SSR) analysis of 14 different loci. Metarhizium brunneum was the most common species isolated from plant roots (84.1% of all isolates), while M. robertsii (11.1%) and M. majus (4.8%) comprised the remainder. The SSR analysis revealed that six multilocus genotypes (MLGs) were present among the M. brunneum and M. robertsii isolates, respectively. A single MLG of M. brunneum represented 66.7%, 79.1% and 79.2% of the total isolates obtained from oat, rye and cabbage, respectively. The isolation of Metarhizium spp. and their MLGs from roots revealed a comparable community composition as previously reported from the same agroecosystem when insect baiting of soil samples was used as isolating technique. No specific MLG association with a certain crop was found. This study highlights the diversity of Metarhizium spp. found in the rhizosphere of different crops within a single agroecosystem and suggests that plants either recruit fungal associates from the surrounding soil environment or even govern the composition of Metarhizium populations. PMID:26407950

  9. In vitro antitrypanosomal activity of the cyclodepsipeptides, cardinalisamides A-C, from the insect pathogenic fungus Cordyceps cardinalis NBRC 103832.

    PubMed

    Umeyama, Akemi; Takahashi, Koichi; Grudniewska, Aleksandra; Shimizu, Mina; Hayashi, Sayaka; Kato, Masayuki; Okamoto, Yasuko; Suenaga, Midori; Ban, Sayaka; Kumada, Toshio; Ishiyama, Aki; Iwatsuki, Masato; Otoguro, Kazuhiko; Omura, Satoshi; Hashimoto, Toshihiro

    2014-02-01

    During the search for new antitrypanosomal drug leads, three new antitrypanosomal compounds, cardinalisamides A-C (1-3), were isolated from cultures of the insect pathogenic fungus Cordyceps cardinalis NBRC 103832. Their structures were elucidated using MS analyses and extensive 2D-heteronuclear NMR. The absolute configurations of 1-3 were addressed by chemical degradation and Marfey's analysis. 1-3 showed in vitro antitrypanosomal activity against Trypanosoma brucei brucei with IC50 values of 8.56, 8.65 and 8.63 μg ml(-1), respectively. PMID:24084682

  10. Differential gene expression in Acromyrmex leaf-cutting ants after challenges with two fungal pathogens.

    PubMed

    Yek, Sze H; Boomsma, Jacobus J; Schiøtt, Morten

    2013-04-01

    Social insects in general and leaf-cutting ants in particular have increased selection pressures on their innate immune system due to their social lifestyle and monoclonality of the symbiotic fungal cultivar. As this symbiosis is obligate for both parties, prophylactic behavioural defences against infections are expected to increase either ant survival or fungus-garden survival, but also to possibly trade off when specific infections differ in potential danger. We examined the effectiveness of prophylactic behaviours and modulations of innate immune defences by a combination of inoculation bioassays and genome-wide transcriptomic studies (RNA-Seq), using an ant pathogen (Metarhizium brunneum) and a fungus-garden pathogen (Escovopsis weberi) and administering inoculations both directly and indirectly (via the symbiotic partner). Upon detection of pathogen conidia, ant workers responded by increasing both general activity and the frequency of specific defence behaviours (self-grooming, allo-grooming, garden-grooming) independent of the pathogen encountered. This trend was also evident in the patterns of gene expression change. Both direct and indirect (via fungus garden) inoculations with Metarhizium induced a general up-regulation of gene expression, including a number of well-known immune-related genes. In contrast, direct inoculation of the fungus garden by Escovopsis induced an overall down-regulation of ant gene expression, whereas indirect inoculation (via the ants) did not, suggesting that increased activity of ants to remove this fungus-garden pathogen is costly and involves trade-offs with the activation of other physiological pathways. PMID:23480581

  11. Variable virulence among isolates of Ascosphaera apis: testing the parasite-pathogen hypothesis for the evolution of polyandry in social insects

    NASA Astrophysics Data System (ADS)

    Lee, G. M.; McGee, P. A.; Oldroyd, B. P.

    2013-03-01

    The queens of many eusocial insect species are polyandrous. The evolution of polyandry from ancestral monoandry is intriguing because polyandry undermines the kin-selected benefits of high intracolonial relatedness that are understood to have been central to the evolution of eusociality. An accumulating body of evidence suggests that polyandry evolved from monoandry in part because genetically diverse colonies better resist infection by pathogens. However, a core assumption of the "parasite-pathogen hypothesis", that there is variation in virulence among strains of pathogens, remains largely untested in vivo. Here, we demonstrate variation in virulence among isolates of Ascosphaera apis, the causative organism of chalkbrood disease in its honey bee ( Apis mellifera) host. More importantly, we show a pathogen-host genotypic interaction for resistance and pathogenicity. Our findings therefore support the parasite-parasite hypothesis as a factor in the evolution of polyandry among eusocial insects.

  12. Targeting of insect epicuticular lipids by the entomopathogenic fungus Beauveria bassiana: hydrocarbon oxidation within the context of a host-pathogen interaction

    PubMed Central

    Pedrini, Nicolás; Ortiz-Urquiza, Almudena; Huarte-Bonnet, Carla; Zhang, Shizhu; Keyhani, Nemat O.

    2013-01-01

    Broad host range entomopathogenic fungi such as Beauveria bassiana attack insect hosts via attachment to cuticular substrata and the production of enzymes for the degradation and penetration of insect cuticle. The outermost epicuticular layer consists of a complex mixture of non-polar lipids including hydrocarbons, fatty acids, and wax esters. Long chain hydrocarbons are major components of the outer waxy layer of diverse insect species, where they serve to protect against desiccation and microbial parasites, and as recognition molecules or as a platform for semiochemicals. Insect pathogenic fungi have evolved mechanisms for overcoming this barrier, likely with sets of lipid degrading enzymes with overlapping substrate specificities. Alkanes and fatty acids are substrates for a specific subset of fungal cytochrome P450 monooxygenases involved in insect hydrocarbon degradation. These enzymes activate alkanes by terminal oxidation to alcohols, which are further oxidized by alcohol and aldehyde dehydrogenases, whose products can enter β-oxidation pathways. B. bassiana contains at least 83 genes coding for cytochrome P450s (CYP), a subset of which are involved in hydrocarbon oxidation, and several of which represent new CYP subfamilies/families. Expression data indicated differential induction by alkanes and insect lipids and four CYP proteins have been partially characterized after heterologous expression in yeast. Gene knockouts revealed a phenotype for only one (cyp52X1) out of six genes examined to date. CYP52X1 oxidizes long chain fatty acids and participates in the degradation of specific epicuticular lipid components needed for breaching the insect waxy layer. Examining the hydrocarbon oxidizing CYP repertoire of pathogens involved in insect epicuticle degradation can lead to the characterization of enzymes with novel substrate specificities. Pathogen targeting may also represent an important co-evolutionary process regarding insect cuticular hydrocarbon

  13. Topography and Land Cover of Watersheds Predicts the Distribution of the Environmental Pathogen Mycobacterium ulcerans in Aquatic Insects

    PubMed Central

    Carolan, Kevin; Garchitorena, Andres; García-Peña, Gabriel E.; Morris, Aaron; Landier, Jordi; Fontanet, Arnaud; Le Gall, Philippe; Texier, Gaëtan; Marsollier, Laurent; Gozlan, Rodolphe E.; Eyangoh, Sara; Lo Seen, Danny; Guégan, Jean-Francois

    2014-01-01

    Background An understanding of the factors driving the distribution of pathogens is useful in preventing disease. Often we achieve this understanding at a local microhabitat scale; however the larger scale processes are often neglected. This can result in misleading inferences about the distribution of the pathogen, inhibiting our ability to manage the disease. One such disease is Buruli ulcer, an emerging neglected tropical disease afflicting many thousands in Africa, caused by the environmental pathogen Mycobacterium ulcerans. Herein, we aim to describe the larger scale landscape process describing the distribution of M. ulcerans. Methodology Following extensive sampling of the community of aquatic macroinvertebrates in Cameroon, we select the 5 dominant insect Orders, and conduct an ecological niche model to describe how the distribution of M. ulcerans positive insects changes according to land cover and topography. We then explore the generalizability of the results by testing them against an independent dataset collected in a second endemic region, French Guiana. Principal Findings We find that the distribution of the bacterium in Cameroon is accurately described by the land cover and topography of the watershed, that there are notable seasonal differences in distribution, and that the Cameroon model does not predict the distribution of M. ulcerans in French Guiana. Conclusions/Significance Future studies of M. ulcerans would benefit from consideration of local structure of the local stream network in future sampling, and further work is needed on the reasons for notable differences in the distribution of this species from one region to another. This work represents a first step in the identification of large-scale environmental drivers of this species, for the purposes of disease risk mapping. PMID:25375173

  14. Production of destruxins from Metarhizium spp. fungi in artificial medium and in endophytically colonized cowpea plants.

    PubMed

    Golo, Patrícia S; Gardner, Dale R; Grilley, Michelle M; Takemoto, Jon Y; Krasnoff, Stuart B; Pires, Marcus S; Fernandes, Éverton K K; Bittencourt, Vânia R E P; Roberts, Donald W

    2014-01-01

    Destruxins (DTXs) are cyclic depsipeptides produced by many Metarhizium isolates that have long been assumed to contribute to virulence of these entomopathogenic fungi. We evaluated the virulence of 20 Metarhizium isolates against insect larvae and measured the concentration of DTXs A, B, and E produced by these same isolates in submerged (shaken) cultures. Eight of the isolates (ARSEF 324, 724, 760, 1448, 1882, 1883, 3479, and 3918) did not produce DTXs A, B, or E during the five days of submerged culture. DTXs were first detected in culture medium at 2-3 days in submerged culture. Galleria mellonella and Tenebrio molitor showed considerable variation in their susceptibility to the Metarhizium isolates. The concentration of DTXs produced in vitro did not correlate with percent or speed of insect kill. We established endophytic associations of M. robertsii and M. acridum isolates in Vigna unguiculata (cowpeas) and Cucumis sativus (cucumber) plants. DTXs were detected in cowpeas colonized by M. robertsii ARSEF 2575 12 days after fungal inoculation, but DTXs were not detected in cucumber. This is the first instance of DTXs detected in plants endophytically colonized by M. robertsii. This finding has implications for new approaches to fungus-based biological control of pest arthropods. PMID:25127450

  15. A single genetic locus in the phytopathogen Pantoea stewartii enables gut colonization and pathogenicity in an insect host.

    PubMed

    Stavrinides, John; No, Alexander; Ochman, Howard

    2010-01-01

    Aphids are typically exposed to a variety of epiphytic and phytopathogenic bacteria, many of which have entomopathogenic potential. Here we describe the interaction between Pantoea stewartii ssp. stewartii DC283 (DC283), an enteric phytopathogen and causal agent of Stewart's wilt, and the pea aphid, Acyrthosiphon pisum. When ingested by aphids, DC283 establishes and aggregates in the crop and gut, preventing honeydew flow and excretion, resulting in aphid death in 72 h. A mutagenesis screen identified a single locus, termed ucp1 (youcannot pass), whose disruption abolishes aphid pathogenicity. Moreover, the expression of ucp1 in Escherichia coli is sufficient to mediate the hindgut aggregation phenotype by this normally avirulent species. Ucp1 is related to six other proteins in the DC283 genome, each having a common N-terminal region and a divergent C-terminus, but only ucp1 has a role in pathogenicity. Based on predicted motifs and secondary structure, Ucp1 is a membrane-bound protein that functions in bacterial adhesion and promotes the formation of aggregates that are lethal to the insect host. These results illustrate that the enteric plant pathogenic bacteria have the capacity to exploit alternative non-plant hosts, and retain genetic determinants for colonizing the gut. PMID:19788413

  16. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal.

    PubMed

    Martini, Xavier; Hoffmann, Mark; Coy, Monique R; Stelinski, Lukasz L; Pelz-Stelinski, Kirsten S

    2015-01-01

    The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such movement of vectors is likely manipulated by a bacterial plant pathogen. We investigated how Candidatus Liberibacter asiaticus (CLas) affects dispersal behavior, flight capacity, and the sexual attraction of its vector, the Asian citrus psyllid (Diaphorina citri Kuwayama). CLas is the putative causal agent of huanglongbing (HLB), which is a disease that threatens the viability of commercial citrus production worldwide. When D. citri developed on CLas-infected plants, short distance dispersal of male D. citri was greater compared to counterparts reared on uninfected plants. Flight by CLas-infected D. citri was initiated earlier and long flight events were more common than by uninfected psyllids, as measured by a flight mill apparatus. Additionally, CLas titers were higher among psyllids that performed long flights than psyllid that performed short flights. Finally, attractiveness of female D. citri that developed on infected plants to male conspecifics increased proportionally with increasing CLas bacterial titers measured within female psyllids. Our study indicates that the phytopathogen, CLas, may manipulate movement and mate selection behavior of their vectors, which is a possible evolved mechanism to promote their own spread. These results have global implications for both current HLB models of disease spread and control strategies. PMID:26083763

  17. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal

    PubMed Central

    Coy, Monique R.; Stelinski, Lukasz L.; Pelz-Stelinski, Kirsten S.

    2015-01-01

    The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such movement of vectors is likely manipulated by a bacterial plant pathogen. We investigated how Candidatus Liberibacter asiaticus (CLas) affects dispersal behavior, flight capacity, and the sexual attraction of its vector, the Asian citrus psyllid (Diaphorina citri Kuwayama). CLas is the putative causal agent of huanglongbing (HLB), which is a disease that threatens the viability of commercial citrus production worldwide. When D. citri developed on CLas-infected plants, short distance dispersal of male D. citri was greater compared to counterparts reared on uninfected plants. Flight by CLas-infected D. citri was initiated earlier and long flight events were more common than by uninfected psyllids, as measured by a flight mill apparatus. Additionally, CLas titers were higher among psyllids that performed long flights than psyllid that performed short flights. Finally, attractiveness of female D. citri that developed on infected plants to male conspecifics increased proportionally with increasing CLas bacterial titers measured within female psyllids. Our study indicates that the phytopathogen, CLas, may manipulate movement and mate selection behavior of their vectors, which is a possible evolved mechanism to promote their own spread. These results have global implications for both current HLB models of disease spread and control strategies. PMID:26083763

  18. Pinellia ternata agglutinin expression in chloroplasts confers broad spectrum resistance against aphid, whitefly, Lepidopteran insects, bacterial and viral pathogens

    PubMed Central

    Jin, Shuangxia; Zhang, Xianlong; Daniell, Henry

    2012-01-01

    Summary Broad spectrum protection against different insects and pathogens requires multigene engineering. However, such broad spectrum protection against biotic stress is provided by a single protein in some medicinal plants. Therefore, tobacco chloroplasts were transformed with the agglutinin gene from Pinellia ternata (pta), a widely cultivated Chinese medicinal herb. Pinellia ternata agglutinin (PTA) was expressed up to 9.2% of total soluble protein in mature leaves. Purified PTA showed similar hemagglutination activity as snowdrop lectin. Artificial diet with purified PTA from transplastomic plants showed marked and broad insecticidal activity. In planta bioassays conducted with T0 or T1 generation PTA lines showed that the growth of aphid Myzus persicae (Sulzer) was reduced by 89%–92% when compared with untransformed (UT) plants. Similarly, the larval survival and total population of whitefly (Bemisia tabaci) on transplastomic lines were reduced by 91%–93% when compared with UT plants. This is indeed the first report of lectin controlling whitefly infestation. When transplastomic PTA leaves were fed to corn earworm (Helicoverpa zea), tobacco budworm (Heliothis virescens) or the beet armyworm (spodoptera exigua), 100% mortality was observed against all these three insects. In planta bioassays revealed Erwinia population to be 10 000-fold higher in control than in PTA lines. Similar results were observed with tobacco mosaic virus (TMV) challenge. Therefore, broad spectrum resistance to homopteran (sap-sucking), Lepidopteran insects as well as anti-bacterial or anti-viral activity observed in PTA lines provides a new option to engineer protection against biotic stress by hyper-expression of an unique protein that is naturally present in a medicinal plant. PMID:22077160

  19. An insecticidal compound produced by an insect-pathogenic bacterium suppresses host defenses through phenoloxidase inhibition.

    PubMed

    Ullah, Ihsan; Khan, Abdul Latif; Ali, Liaqat; Khan, Abdur Rahim; Waqas, Muhammad; Lee, In-Jung; Shin, Jae-Ho

    2014-01-01

    A bioassay-guided column chromatographic strategy was adopted in the present study to fractionate the culture extract of Photorhabdus temperata M1021 to identify potential insecticidal and antimicrobial compounds. An ethyl acetate (EtOAc) culture extract of P. temperata was assayed against Galleria mellonella larvae through intra-hemocoel injection and exhibited 100% insect mortality within 60 h. The EtOAc fraction and an isolated compound exhibited phenoloxidase (PO) inhibition of up to 60% and 63%, respectively. The compound was identified as 1,2-benzenedicarboxylic acid (phthalic acid, PA) by gas chromatography-mass spectrometry and nuclear magnetic resonance. PA exhibited insecticidal activity against G. mellonella in a dose-dependent manner, and 100% insect mortality was observed at 108 h after injection of 1 M PA. In a PO inhibition assay, 0.5 and 1 M concentrations of PA were found to inhibit PO activity by 74% and 82%, respectively; and in a melanotic nodule formation assay, nodule formation was significantly inhibited (27 and 10 nodules) by PA (0.5 and 1 M, respectively). PA was furthermore found to have substantial antioxidant activity and maximum antioxidant activity was 64.7% for 0.5 M PA as compare to control. Antibacterial activity was assessed by The MIC values ranged from 0.1 M to 0.5 M of PA. This study reports a multifunctional PA, a potential insecticidal agent, could a factor of insect mortality along with other toxins produced by P. temperata M1021. PMID:25514230

  20. The pathogen causing Dutch elm disease makes host trees attract insect vectors

    PubMed Central

    McLeod, Geoff; Gries, Regine; von Reuß, Stephan H; Rahe, James E; McIntosh, Rory; König, Wilfried A; Gries, Gerhard

    2005-01-01

    Dutch elm disease is caused by the fungal pathogen Ophiostoma novo-ulmi which is transmitted by the native elm bark beetle, Hylurgopinus rufipes. We have found that four semiochemicals (the monoterpene (−)-β-pinene and the sesquiterpenes (−)-α-cubebene, (+)-spiroaxa-5,7-diene and (+)-δ-cadinene) from diseased American elms, Ulmus americana, synergistically attract H. rufipes, and that sesquiterpene emission is upregulated in elm trees inoculated with O. novo-ulmi. The fungus thus manipulates host trees to enhance their apparency to foraging beetles, a strategy that increases the probability of transportation of the pathogen to new hosts. PMID:16271975

  1. Transcriptional control of fungal cell cycle and cellular events by Fkh2, a forkhead transcription factor in an insect pathogen

    PubMed Central

    Wang, Juan-Juan; Qiu, Lei; Cai, Qing; Ying, Sheng-Hua; Feng, Ming-Guang

    2015-01-01

    Transcriptional control of the cell cycle by forkhead (Fkh) transcription factors is likely associated with fungal adaptation to host and environment. Here we show that Fkh2, an ortholog of yeast Fkh1/2, orchestrates cell cycle and many cellular events of Beauveria bassiana, a filamentous fungal insect pathogen. Deletion of Fkh2 in B. bassiana resulted in dramatic down-regulation of the cyclin-B gene cluster and hence altered cell cycle (longer G2/M and S, but shorter G0/G1, phases) in unicellular blastospores. Consequently, ΔFkh2 produced twice as many, but smaller, blastospores than wild-type under submerged conditions, and formed denser septa and shorter/broader cells in aberrantly branched hyphae. In these hyphae, clustered genes required for septation and conidiation were remarkedly up-regulated, followed by higher yield and slower germination of aerial conidia. Moreover, ΔFkh2 displayed attenuated virulence and decreased tolerance to chemical and environmental stresses, accompanied with altered transcripts and activities of phenotype-influencing proteins or enzymes. All the changes in ΔFkh2 were restored by Fkh2 complementation. All together, Fkh2-dependent transcriptional control is vital for the adaptation of B. bassiana to diverse habitats of host insects and hence contributes to its biological control potential against arthropod pests. PMID:25955538

  2. Safe housing ensured by an electric field screen that excludes insect-net permeating haematophagous mosquitoes carrying human pathogens

    NASA Astrophysics Data System (ADS)

    Matsuda, Y.; Kakutani, K.; Nonomura, T.; Kimbara, J.; Osamura, K.; Kusakar, S.; Toyoda, H.

    2015-10-01

    An electric field screen can be used to keep mosquitoes out of houses with open windows. In this study, doubly charged dipolar electric field screens (DD-screens) were used to capture mosquitoes entering through a window. The screen had two components: three layers of insulated conductor iron wires (ICWs) in parallel arrays and two electrostatic direct current (DC) voltage generators that supplied negative or positive voltages to the ICWs. Within each layer, the ICWs were parallel at 5-mm intervals, and connected to each other and to a negative or positive voltage generator. The negatively and positively charged ICWs are represented as ICW(-) and ICW(+), respectively. The screen consisted of one ICW(+) layer with an ICW(-) layer on either side. The Asian tiger mosquito (Aedes albopictus) and house mosquito (Culex pipiens) were used as models of vectors carrying viral pathogens. Adult mosquitoes were blown into the space between the ICWs by sending compressed air through the tip of an insect aspirator to determine the voltage range that captured all of the test insects. Wind speed was measured at the surface of the ICW using a sensitive anemometer. The result showed that at ≥ 1.2 kV, the force was strong enough that the ICWs captured all of the mosquitoes, despite a wind speed of 7 m/s. Therefore, the DD-screen could serve as a physical barrier to prevent noxious mosquitoes from entering houses with good air penetration.

  3. Transcriptional control of fungal cell cycle and cellular events by Fkh2, a forkhead transcription factor in an insect pathogen.

    PubMed

    Wang, Juan-Juan; Qiu, Lei; Cai, Qing; Ying, Sheng-Hua; Feng, Ming-Guang

    2015-01-01

    Transcriptional control of the cell cycle by forkhead (Fkh) transcription factors is likely associated with fungal adaptation to host and environment. Here we show that Fkh2, an ortholog of yeast Fkh1/2, orchestrates cell cycle and many cellular events of Beauveria bassiana, a filamentous fungal insect pathogen. Deletion of Fkh2 in B. bassiana resulted in dramatic down-regulation of the cyclin-B gene cluster and hence altered cell cycle (longer G2/M and S, but shorter G0/G1, phases) in unicellular blastospores. Consequently, ΔFkh2 produced twice as many, but smaller, blastospores than wild-type under submerged conditions, and formed denser septa and shorter/broader cells in aberrantly branched hyphae. In these hyphae, clustered genes required for septation and conidiation were remarkedly up-regulated, followed by higher yield and slower germination of aerial conidia. Moreover, ΔFkh2 displayed attenuated virulence and decreased tolerance to chemical and environmental stresses, accompanied with altered transcripts and activities of phenotype-influencing proteins or enzymes. All the changes in ΔFkh2 were restored by Fkh2 complementation. All together, Fkh2-dependent transcriptional control is vital for the adaptation of B. bassiana to diverse habitats of host insects and hence contributes to its biological control potential against arthropod pests. PMID:25955538

  4. Replacement of a dominant viral pathogen by a fungal pathogen does not alter the collapse of a regional forest insect outbreak.

    PubMed

    Hajek, Ann E; Tobin, Patrick C; Haynes, Kyle J

    2015-03-01

    Natural enemies and environmental factors likely both influence the population cycles of many forest-defoliating insect species. Previous work suggests precipitation influences the spatiotemporal patterns of gypsy moth outbreaks in North America, and it has been hypothesized that precipitation could act indirectly through effects on pathogens. We investigated the potential role of climatic and environmental factors in driving pathogen epizootics and parasitism at 57 sites over an area of ≈72,300 km(2) in four US mid-Atlantic states during the final year (2009) of a gypsy moth outbreak. Prior work has largely reported that the Lymantria dispar nucleopolyhedrovirus (LdNPV) was the principal mortality agent responsible for regional collapses of gypsy moth outbreaks. However, in the gypsy moth outbreak-prone US mid-Atlantic region, the fungal pathogen Entomophaga maimaiga has replaced the virus as the dominant source of mortality in dense host populations. The severity of the gypsy moth population crash, measured as the decline in egg mass densities from 2009 to 2010, tended to increase with the prevalence of E. maimaiga and larval parasitoids, but not LdNPV. A significantly negative spatial association was detected between rates of fungal mortality and parasitism, potentially indicating displacement of parasitoids by E. maimaiga. Fungal, viral, and parasitoid mortality agents differed in their associations with local abiotic and biotic conditions, but precipitation significantly influenced both fungal and viral prevalence. This study provides the first spatially robust evidence of the dominance of E. maimaiga during the collapse of a gypsy moth outbreak and highlights the important role played by microclimatic conditions. PMID:25510217

  5. Horizontal Transmission of Beauveria bassiana (Hypocreales: Cordycipitaceae) and Metarhizium anisopliae (Hypocreales: Clavicipitaceae) in Musca domestica (Diptera: Muscidae).

    PubMed

    Cárcamo, M C; Felchicher, F; Duarte, J P; Bernardi, E; Ribeiro, P B

    2015-08-01

    Beauveria bassiana Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin are fungi with potential for controlling Musca domestica L. However, the impact on this dipteral may vary depending on the fungal isolates and the methodology used. This study evaluated the pathogenicity of direct application and horizontal transmission of B. bassiana (CG240) and M. anisopliae (CG34) on adult M. domestica individuals. The impact of B. bassiana and M. anisopliae on M. domestica was evaluated at the concentrations 2 × 10(4), 2 × 10(5), 2 × 10(6), and 2 × 10(7) conidia/ml. Horizontal transmission was also estimated between sexes at different infection periods of the vector insect. The mortality of adult M. domestica individuals directly infected with B. bassiana was above 90%, and the mortality of those infected with M. anisopliae ranged from 25.50 to 97.78%. Horizontal transmission of B. bassiana caused the death of 100% of individuals, in turn, that of M. anisopliae killed 55% of male and 100% of female individuals. Horizontal transmission of fungi was negatively influenced by time. This study shows the potential of these fungi for controlling M. domestica, both with the direct implementation strategy and horizontal transmission. However, field studies are needed to evaluate the capacity to decrease the M. domestica population using these alternatives. PMID:26470298

  6. Interactions Within Susceptible Hosts Drive Establishment of Genetically Distinct Variants of an Insect-Borne Pathogen.

    PubMed

    Blaisdell, G K; Zhang, S; Bratburd, J R; Daane, K M; Cooper, M L; Almeida, R P P

    2015-08-01

    Coinfections are common, leading to pathogen interactions during transmission and establishment in a host. However, few studies have tested the relative strengths of pathogen interactions in vectors and hosts that determine the outcome of infection. We tested interactions between two genetically distinct variants of the mealybug-transmitted Grapevine leafroll-associated virus 3. The transmission efficiency of each variant in single variant inoculations by two vector species was determined. The effects of vector species, a coinfected source, and simultaneous inoculation from multiple hosts to one host on variant establishment were examined. Within-vector interactions could have a role in transmission from hosts containing mixed infections, but not when vectors were moved from separate singly infected source plants to a single recipient plant. The invasive Planococcus ficus (Signoret) was a more efficient vector than Pseudococcus viburni (Signoret). Transmission efficiency of the two variants did not differ in single variant inoculations. Overall infections were the same whether from singly or coinfected source plants. In mixed inoculations, establishment of one variant was reduced. Mixed inoculations from two singly infected source plants resulted in fewer mixed infections than expected by chance. Therefore, the observed outcome was determined subsequent to host inoculation rather than in the vector. The outcome may be due to resource competition between pathogens. Alternatively apparent competition may be responsible; the pathogens' differential ability to overcome host defenses and colonize the host may determine the final outcome of new infections. Detailed knowledge of interactions between pathogens during transmission and establishment could improve understanding and management of disease spread. PMID:26470292

  7. Multiplexed microsatellite markers for seven Metarhizium species.

    PubMed

    Mayerhofer, Johanna; Lutz, Andy; Widmer, Franco; Rehner, Stephen A; Leuchtmann, Adrian; Enkerli, Jürg

    2015-11-01

    Cross-species transferability of 41 previously published simple sequence repeat (SSR) markers was assessed for 11 species of the entomopathogenic fungus Metarhizium. A collection of 65 Metarhizium strains including all 54 used in a recent phylogenetic revision of the genus were characterized. Between 15 and 34 polymorphic SSR markers produced scorable PCR amplicons in seven species, including M. anisopliae, M. brunneum, M. guizhouense, M. lepidiotae, M. majus, M. pingshaense, and M. robertsii. To provide genotyping tools for concurrent analysis of these seven species fifteen markers grouped in five multiplex pools were selected based on high allelic diversity and easy scorability of SSR chromatograms. PMID:26407949

  8. The effects of the avoidance of infectious hosts on infection risk in an insect-pathogen interaction.

    PubMed

    Eakin, Libby; Wang, Mei; Dwyer, Greg

    2015-01-01

    In many animal host-pathogen interactions, uninfected hosts either avoid or are attracted to infected conspecifics, but understanding how such behaviors affect infection risk is difficult. In experiments, behaviors are often eliminated entirely, which allows demonstration that a behavior affects risk but makes it impossible to quantify effects of individual behaviors. In models, host behaviors have been studied using ordinary differential equations, which can be easily analyzed but cannot be used to relate individual behaviors to risk. For many insect baculoviruses, however, quantifying effects of behavior on risk is straightforward because transmission occurs when host larvae accidentally consume virus-contaminated foliage. Moreover, increases in computing power have made it possible to fit complex models to data. We therefore used experiments to quantify the behavior of gypsy moth larvae feeding on oak leaves contaminated with virus-infected cadavers, and we tested for effects of cadaver-avoidance behavior by fitting stochastic simulation models to our data. The models that best explain the data include cadaver avoidance, and comparison of models that do and do not include cadaver avoidance shows that this behavior substantially reduces infection risk. Our work demonstrates that host behaviors that affect exposure risk play a key role in baculovirus transmission and adds to the growing consensus that host behavior can strongly alter pathogen transmission rates. PMID:25560556

  9. Basic Leucine Zipper (bZIP) Domain Transcription Factor MBZ1 Regulates Cell Wall Integrity, Spore Adherence, and Virulence in Metarhizium robertsii *

    PubMed Central

    Huang, Wei; Shang, Yanfang; Chen, Peilin; Cen, Kai; Wang, Chengshu

    2015-01-01

    Transcription factors (TFs) containing the basic leucine zipper (bZIP) domain are widely distributed in eukaryotes and display an array of distinct functions. In this study, a bZIP-type TF gene (MBZ1) was deleted and functionally characterized in the insect pathogenic fungus Metarhizium robertsii. The deletion mutant (ΔMBZ1) showed defects in cell wall integrity, adhesion to hydrophobic surfaces, and topical infection of insects. Relative to the WT, ΔMBZ1 was also impaired in growth and conidiogenesis. Examination of putative target gene expression indicated that the genes involved in chitin biosynthesis were differentially transcribed in ΔMBZ1 compared with the WT, which led to the accumulation of a higher level of chitin in mutant cell walls. MBZ1 exhibited negative regulation of subtilisin proteases, but positive control of an adhesin gene, which is consistent with the observation of effects on cell autolysis and a reduction in spore adherence to hydrophobic surfaces in ΔMBZ1. Promoter binding assays indicated that MBZ1 can bind to different target genes and suggested the possibility of heterodimer formation to increase the diversity of the MBZ1 regulatory network. The results of this study advance our understanding of the divergence of bZIP-type TFs at both intra- and interspecific levels. PMID:25673695

  10. Factors affecting the initial adhesion and retention of the plant pathogen Xylella fastidiosa in the foregut of an insect vector.

    PubMed

    Killiny, Nabil; Almeida, Rodrigo P P

    2014-01-01

    Vector transmission of bacterial plant pathogens involves three steps: pathogen acquisition from an infected host, retention within the vector, and inoculation of cells into susceptible tissue of an uninfected plant. In this study, a combination of plant and artificial diet systems were used to determine the importance of several genes on the initial adhesion and retention of the bacterium Xylella fastidiosa to an efficient insect vector. Mutant strains included fimbrial (fimA and pilB) and afimbrial (hxfA and hxfB) adhesins and three loci involved in regulatory systems (rpfF, rpfC, and cgsA). Transmission assays with variable retention time indicated that HxfA and HxfB were primarily important for early adhesion to vectors, while FimA was necessary for both adhesion and retention. The long pilus protein PilB was not deficient in initial adhesion but may be important for retention. Genes upregulated under the control of rpfF are important for both initial adhesion and retention, as transmission rates of this mutant strain were initially low and decreased over time, while disruption of rpfC and cgsA yielded trends similar to that shown by the wild-type control. Because induction of an X. fastidiosa transmissible state requires pectin, a series of experiments were used to test the roles of a polygalacturonase (pglA) and the pectin and galacturonic acid carbohydrates on the transmission of X. fastidiosa. Results show that galacturonic acid, or PglA activity breaking pectin into its major subunit (galacturonic acid), is required for X. fastidiosa vector transmission using an artificial diet system. This study shows that early adhesion and retention of X. fastidiosa are mediated by different factors. It also illustrates that the interpretation of results of vector transmission experiments, in the context of vector-pathogen interaction studies, is highly dependent on experimental design. PMID:24185853

  11. Exposure of Bed Bugs to Metarhizium anisopliae at Different Humidities.

    PubMed

    Ulrich, Kevin R; Feldlaufer, Mark F; Kramer, Matthew; St Leger, Raymond J

    2014-12-01

    Bed bugs Cimex lectularius L. were exposed to conidia (spores) of the entomopathogenic fungus Metarhizium anisopliae by feeding, aerosol spray, or contact with a treated surface. Feeding experiments demonstrated that bed bugs were innately susceptible to this fungus. However, only at 98% humidity were mortality rates high, regardless of whether bed bugs were sprayed with a fungal solution or contacted a treated surface. Mortality in treated bed bugs at ambient humidity did not increase when these bed bugs were kept in aggregation with other bed bugs that had recently blood fed to repletion. Based on these laboratory studies, we conclude that M. anisopliae is a poor pathogen for use in control of bed bugs, particularly at humidities that would likely be encountered under field conditions. PMID:26470085

  12. Temporal interactions of plant - insect - predator after infection of bacterial pathogen on rice plants.

    PubMed

    Sun, Ze; Liu, Zhuang; Zhou, Wen; Jin, Huanan; Liu, Hao; Zhou, Aiming; Zhang, Aijun; Wang, Man-Qun

    2016-01-01

    Pathogenic infection on plants may affect interactions of host-plants with their herbivores, as well as the herbivores with their predators. In this study, the effects of infection by pathogenic bacterium Xanthomonas oryzae pv. oryzae (Xoo), which causes a vascular disease in rice, on rice plants and consequent interactions with a rice herbivore, brown rice planthopper (BPH) Nilaparvata lugens, and its major predator, Cyrtorhinus lividipennis, were investigated. The results showed that the rice plants exhibited increased resistance to BPH only at 3 d post-inoculation of Xoo, while the Xoo infection did not affect the development and fecundity of BPH. BPH exhibited a higher preference to Xoo infected rice plants, whereas C. lividipennis preferred the Xoo infected rice plants after BPH fed, but preferred healthy rice plants without BPH fed. Volatile organic compounds emitted from Xoo rice were significantly higher than those from healthy rice plants, Xoo infection on BPH fed plants caused rice plants to emit more the herbivore-induced plant volatiles, while all of these changes correlated to the temporal dimension. These results demonstrated that Xoo infection significantly influenced the interactions of rice plants with two non-vectors, BPH and its predator, although these effects exhibited in a temporal pattern after infection. PMID:27185548

  13. Temporal interactions of plant - insect - predator after infection of bacterial pathogen on rice plants

    PubMed Central

    Sun, Ze; Liu, Zhuang; Zhou, Wen; Jin, Huanan; Liu, Hao; Zhou, Aiming; Zhang, Aijun; Wang, Man-Qun

    2016-01-01

    Pathogenic infection on plants may affect interactions of host-plants with their herbivores, as well as the herbivores with their predators. In this study, the effects of infection by pathogenic bacterium Xanthomonas oryzae pv. oryzae (Xoo), which causes a vascular disease in rice, on rice plants and consequent interactions with a rice herbivore, brown rice planthopper (BPH) Nilaparvata lugens, and its major predator, Cyrtorhinus lividipennis, were investigated. The results showed that the rice plants exhibited increased resistance to BPH only at 3 d post-inoculation of Xoo, while the Xoo infection did not affect the development and fecundity of BPH. BPH exhibited a higher preference to Xoo infected rice plants, whereas C. lividipennis preferred the Xoo infected rice plants after BPH fed, but preferred healthy rice plants without BPH fed. Volatile organic compounds emitted from Xoo rice were significantly higher than those from healthy rice plants, Xoo infection on BPH fed plants caused rice plants to emit more the herbivore-induced plant volatiles, while all of these changes correlated to the temporal dimension. These results demonstrated that Xoo infection significantly influenced the interactions of rice plants with two non-vectors, BPH and its predator, although these effects exhibited in a temporal pattern after infection. PMID:27185548

  14. Further Progress with Metarhizium Microsclerotial Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microsclerotium production by Metarhizium anisopliae, previously reported for flask scale, was successfully achieved at a 100-Liter fermenter scale. The resulting granular formulations readily conidiated on water agar or in moist soil to the same extent as reported for flask fermentations. Both Phar...

  15. PROTEOMIC ANALYSIS OF ALLERGENS FROM METARHIZIUM ANISOPLIAE

    EPA Science Inventory

    Introduction

    The goal of this project is the identification and characterization of allergens from the fungus Metarhizium anisopliae, using mass spectrometry (MS). The US EPA, under the "Children at Risk" program, is currently addressing the problem of indoor fungal bioaer...

  16. Improving Sterile Insect Technique (SIT) for tsetse flies through research on their symbionts and pathogens

    PubMed Central

    Abd-Alla, Adly M.M.; Bergoin, Max; Parker, Andrew G.; Maniania, Nguya K.; Vlak, Just M.; Bourtzis, Kostas; Boucias, Drion G.; Aksoy, Serap

    2013-01-01

    Tsetse flies (Diptera: Glossinidae) are the cyclical vectors of the trypanosomes, which cause human African trypanosomosis (HAT) or sleeping sickness in humans and African animal trypanosomosis (AAT) or nagana in animals. Due to the lack of effective vaccines and inexpensive drugs for HAT, and the development of resistance of the trypanosomes against the available trypanocidal drugs, vector control remains the most efficient strategy for sustainable management of these diseases. Among the control methods used for tsetse flies, Sterile Insect Technique (SIT), in the frame of area-wide integrated pest management (AW-IPM), represents an effective tactic to suppress and/or eradicate tsetse flies. One constraint in implementing SIT is the mass production of target species. Tsetse flies harbor obligate bacterial symbionts and salivary gland hypertrophy virus which modulate the fecundity of the infected flies. In support of the future expansion of the SIT for tsetse fly control, the Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture implemented a six year Coordinated Research Project (CRP) entitled “Improving SIT for Tsetse Flies through Research on their Symbionts and Pathogens”. The consortium focused on the prevalence and the interaction between the bacterial symbionts and the virus, the development of strategies to manage virus infections in tsetse colonies, the use of entomopathogenic fungi to control tsetse flies in combination with SIT, and the development of symbiont-based strategies to control tsetse flies and trypanosomosis. The results of the CRP and the solutions envisaged to alleviate the constraints of the mass rearing of tsetse flies for SIT are presented in this special issue. PMID:22841636

  17. Secretome of the Biocontrol Agent Metarhizium anisopliae Induced by the Cuticle of the Cotton Pest Dysdercus peruvianus Reveals New Insights into Infection

    PubMed Central

    2015-01-01

    Metarhizium anisopliae is an entomopathogenic fungus that has evolved specialized strategies to infect insect hosts. Here we analyzed secreted proteins related to Dysdercus peruvianus infection. Using shotgun proteomics, abundance changes in 71 proteins were identified after exposure to host cuticle. Among these proteins were classical fungal effectors secreted by pathogens to degrade physical barriers and alter host physiology. These include lipolytic enzymes, Pr1A, B, C, I, and J proteases, ROS-related proteins, oxidorreductases, and signaling proteins. Protein interaction networks were generated postulating interesting candidates for further studies, including Pr1C, based on possible functional interactions. On the basis of these results, we propose that M. anisopliae is degrading host components and actively secreting proteins to manage the physiology of the host. Interestingly, the secretion of these factors occurs in the absence of a host response. The findings presented here are an important step in understanding the host–pathogen interaction and developing more efficient biocontrol of D. peruvianus by M. anisopliae. PMID:24702058

  18. Field damage of sorghum (Sorghum bicolor) with reduced lignin levels by naturally occurring insect pests and pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mutant lines of sorghum with low levels of lignin are potentially useful for bioenergy production, but may have problems with insects or disease. Field grown normal and low lignin bmr6 and bmr12 sorghum (Sorghum bicolor) were examined for insect and disease damage in the field, and insect damage in ...

  19. Identification of a new Alcaligenes faecalis strain MOR02 and assessment of its toxicity and pathogenicity to insects.

    PubMed

    Quiroz-Castañeda, Rosa Estela; Mendoza-Mejía, Ared; Obregón-Barboza, Verónica; Martínez-Ocampo, Fernando; Hernández-Mendoza, Armando; Martínez-Garduño, Felipe; Guillén-Solís, Gabriel; Sánchez-Rodríguez, Federico; Peña-Chora, Guadalupe; Ortíz-Hernández, Laura; Gaytán-Colín, Paul; Dantán-González, Edgar

    2015-01-01

    We report the isolation of a bacterium from Galleria mellonella larva and its identification using genome sequencing and phylogenomic analysis. This bacterium was named Alcaligenes faecalis strain MOR02. Microscopic analyses revealed that the bacteria are located in the esophagus and intestine of the nematodes Steinernema feltiae, S. carpocapsae, and H. bacteriophora. Using G. mellonella larvae as a model, when the larvae were injected with 24,000 CFU in their hemocoel, more than 96% mortality was achieved after 24 h. Additionally, toxicity assays determined that 1 μg of supernatant extract from A. faecalis MOR02 killed more than 70% G. mellonella larvae 96 h after injection. A correlation of experimental data with sequence genome analyses was also performed. We discovered genes that encode proteins and enzymes that are related to pathogenicity, toxicity, and host/environment interactions that may be responsible for the observed phenotypic characteristics. Our data demonstrates that the bacteria are able to use different strategies to colonize nematodes and kill insects to their own benefit. However, there remains an extensive group of unidentified microorganisms that could be participating in the infection process. Additionally, a nematode-bacterium association could be established probably as a strategy of dispersion and colonization. PMID:25667924

  20. Identification of a New Alcaligenes faecalis Strain MOR02 and Assessment of Its Toxicity and Pathogenicity to Insects

    PubMed Central

    Mendoza-Mejía, Ared; Obregón-Barboza, Verónica; Martínez-Ocampo, Fernando; Hernández-Mendoza, Armando; Martínez-Garduño, Felipe; Guillén-Solís, Gabriel; Sánchez-Rodríguez, Federico; Peña-Chora, Guadalupe; Ortíz-Hernández, Laura; Gaytán-Colín, Paul; Dantán-González, Edgar

    2015-01-01

    We report the isolation of a bacterium from Galleria mellonella larva and its identification using genome sequencing and phylogenomic analysis. This bacterium was named Alcaligenes faecalis strain MOR02. Microscopic analyses revealed that the bacteria are located in the esophagus and intestine of the nematodes Steinernema feltiae, S. carpocapsae, and H. bacteriophora. Using G. mellonella larvae as a model, when the larvae were injected with 24,000 CFU in their hemocoel, more than 96% mortality was achieved after 24 h. Additionally, toxicity assays determined that 1 μg of supernatant extract from A. faecalis MOR02 killed more than 70% G. mellonella larvae 96 h after injection. A correlation of experimental data with sequence genome analyses was also performed. We discovered genes that encode proteins and enzymes that are related to pathogenicity, toxicity, and host/environment interactions that may be responsible for the observed phenotypic characteristics. Our data demonstrates that the bacteria are able to use different strategies to colonize nematodes and kill insects to their own benefit. However, there remains an extensive group of unidentified microorganisms that could be participating in the infection process. Additionally, a nematode-bacterium association could be established probably as a strategy of dispersion and colonization. PMID:25667924

  1. The silencing suppressor (NSs) protein of the plant virus Tomato spotted wilt virus enhances heterologous protein expression and baculovirus pathogenicity in cells and lepidopteran insects.

    PubMed

    de Oliveira, Virgínia Carla; da Silva Morgado, Fabricio; Ardisson-Araújo, Daniel Mendes Pereira; Resende, Renato Oliveira; Ribeiro, Bergmann Morais

    2015-11-01

    In this work, we showed that cell death induced by a recombinant (vAcNSs) Autographa californica multiple nucleopolyhedrovirus (AcMNPV) expressing the silencing suppressor (NSs) protein of Tomato spotted wilt virus (TSWV) was enhanced on permissive and semipermissive cell lines. The expression of a heterologous gene (firefly luciferase) during co-infection of insect cells with vAcNSs and a second recombinant baculovirus (vAgppolhfluc) was shown to increase when compared to single vAgppolhfluc infections. Furthermore, the vAcNSs mean time-to-death values were significantly lower than those for wild-type AcMNPV on larvae of Spodoptera frugiperda and Anticarsia gemmatalis. These results showed that the TSWV-NSs protein could efficiently increase heterologous protein expression in insect cells as well as baculovirus pathogenicity and virulence, probably by suppressing the gene-silencing machinery in insects. PMID:26323262

  2. New ex vivo reporter assay system reveals that σ factors of an unculturable pathogen control gene regulation involved in the host switching between insects and plants.

    PubMed

    Ishii, Yoshiko; Kakizawa, Shigeyuki; Oshima, Kenro

    2013-08-01

    Analysis of the environmental regulation of bacterial gene expression is important for understanding the nature, pathogenicity, and infection route of many pathogens. "Candidatus Phytoplasma asteris", onion yellows strain M (OY-M), is a phytopathogenic bacterium that is able to adapt to quite different host environments, including plants and insects, with a relatively small ~850 kb genome. The OY-M genome encodes two sigma (σ) factors, RpoD and FliA, that are homologous to Escherichia coli σ(70) and σ(28) , respectively. Previous studies show that gene expression of OY-M dramatically changes upon the response to insect and plant hosts. However, very little is known about the relationship between the two σ factors and gene regulatory systems in OY-M, because phytoplasma cannot currently be cultured in vitro. Here, we developed an Escherichia coli-based ex vivo reporter assay (EcERA) system to evaluate the transcriptional induction of phytoplasmal genes by the OY-M-derived σ factors. EcERA revealed that highly expressed genes in insect and plant hosts were regulated by RpoD and FliA, respectively. We also demonstrated that rpoD expression was significantly higher in insect than in plant hosts and fliA expression was similar between the hosts. These data indicate that phytoplasma-derived RpoD and FliA play key roles in the transcriptional switching mechanism during host switching between insects and plants. Our study will be invaluable to understand phytoplasmal transmission, virulence expression in plants, and the effect of infection on insect fitness. In addition, the novel EcERA system could be broadly applied to reveal transcriptional regulation mechanisms in other unculturable bacteria. PMID:23723081

  3. Induced Release of a Plant-Defense Volatile ‘Deceptively’ Attracts Insect Vectors to Plants Infected with a Bacterial Pathogen

    PubMed Central

    Mann, Rajinder S.; Ali, Jared G.; Hermann, Sara L.; Tiwari, Siddharth; Pelz-Stelinski, Kirsten S.; Alborn, Hans T.; Stelinski, Lukasz L.

    2012-01-01

    Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las), affects host preference behavior of its psyllid (Diaphorina citri Kuwayama) vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of specific headspace

  4. New ex vivo reporter assay system reveals that σ factors of an unculturable pathogen control gene regulation involved in the host switching between insects and plants

    PubMed Central

    Ishii, Yoshiko; Kakizawa, Shigeyuki; Oshima, Kenro

    2013-01-01

    Abstract Analysis of the environmental regulation of bacterial gene expression is important for understanding the nature, pathogenicity, and infection route of many pathogens. “Candidatus Phytoplasma asteris”, onion yellows strain M (OY-M), is a phytopathogenic bacterium that is able to adapt to quite different host environments, including plants and insects, with a relatively small ∼850 kb genome. The OY-M genome encodes two sigma (σ) factors, RpoD and FliA, that are homologous to Escherichia coli σ70 and σ28, respectively. Previous studies show that gene expression of OY-M dramatically changes upon the response to insect and plant hosts. However, very little is known about the relationship between the two σ factors and gene regulatory systems in OY-M, because phytoplasma cannot currently be cultured in vitro. Here, we developed an Escherichia coli-based ex vivo reporter assay (EcERA) system to evaluate the transcriptional induction of phytoplasmal genes by the OY-M-derived σ factors. EcERA revealed that highly expressed genes in insect and plant hosts were regulated by RpoD and FliA, respectively. We also demonstrated that rpoD expression was significantly higher in insect than in plant hosts and fliA expression was similar between the hosts. These data indicate that phytoplasma-derived RpoD and FliA play key roles in the transcriptional switching mechanism during host switching between insects and plants. Our study will be invaluable to understand phytoplasmal transmission, virulence expression in plants, and the effect of infection on insect fitness. In addition, the novel EcERA system could be broadly applied to reveal transcriptional regulation mechanisms in other unculturable bacteria. Phytoplasma, an unculturable plant pathogen, could infect plant and insect cells, and dramatically changes their genes upon the response to these hosts. By a new system developed in this study, interactions between phytoplasma promoters and sigma factors were

  5. A multilocus phylogeny of the Metarhizium anisopliae lineage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metarhizium anisopliae, the type species of the anamorph entomopathogenic genus Metarhizium, is currently composed of four varieties and has been demonstrated to be closely associated with M. taii, M. pingshaense, and M. guizhouense. In this study we evaluate the phylogenetic relationships within t...

  6. Phylogenetic diversity of Brazilian Metarhizium associated with sugarcane agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological control of spittlebug with Metarhizium in sugarcane is an example of the successful application of sustainable pest management in Brazil. However little is known about the richness, distribution and ecology of Metarhizium species in the agroecosystems and natural environments of Brazil. W...

  7. Diatomaceous earth and oil enhance effectiveness of Metarhizium anisopliae against Triatoma infestans.

    PubMed

    Luz, Christian; Rodrigues, Juscelino; Rocha, Luiz F N

    2012-04-01

    Entomopathogenic fungi, especially Metarhizium anisopliae, have potential for integrated control of peridomestic triatomine bugs. However, the high susceptibility of these vectors to fungal infection at elevated ambient humidities decreases in the comparatively dry conditions that often prevail in their microhabitats. A formulation adapted to this target pest that induces high and quick mortality can help to overcome these drawbacks. In the present study diatomaceous earth, which is used against pests of stored grains or as an additive to mycoinsecticides, delayed but did not reduce in vitro germination of M. anisopliae s.l. IP 46 conidia after >24h agitation without affecting viability, and did not hamper the survival of Triatoma infestans nymphs exposed to treated surfaces. The settling behavior of nymphs on a treated surface in choice tests depended on the concentration of diatomaceous earth and ambient light level. Conidia formulated with diatomaceous earth and a vegetable oil synergized the insecticidal effect of the fungus in nymphs, and quickly killed all treated insects, even at 75% relative humidity (LT(90) 8.3 days) where unformulated conidia caused only 25% mortality after a 25 days exposure. The improved performance of a combined oil and desiccant dust formulation of this Metarhizium isolate raises the likelihood for its successful mycoinsecticidal use for triatomine control and, apparently, against other domestic insect pests. PMID:22155570

  8. Two volatile organic compounds trigger plant self-defense against a bacterial pathogen and a sucking insect in cucumber under open field conditions.

    PubMed

    Song, Geun Cheol; Ryu, Choong-Min

    2013-01-01

    Systemic acquired resistance (SAR) is a plant self-defense mechanism against a broad-range of pathogens and insect pests. Among chemical SAR triggers, plant and bacterial volatiles are promising candidates for use in pest management, as these volatiles are highly effective, inexpensive, and can be employed at relatively low concentrations compared with agrochemicals. However, such volatiles have some drawbacks, including the high evaporation rate of these compounds after application in the open field, their negative effects on plant growth, and their inconsistent levels of effectiveness. Here, we demonstrate the effectiveness of volatile organic compound (VOC)-mediated induced resistance against both the bacterial angular leaf spot pathogen, Pseudononas syringae pv. lachrymans, and the sucking insect aphid, Myzus persicae, in the open field. Using the VOCs 3-pentanol and 2-butanone where fruit yields increased gave unexpectedly, a significant increase in the number of ladybird beetles, Coccinella septempunctata, a natural enemy of aphids. The defense-related gene CsLOX was induced by VOC treatment, indicating that triggering the oxylipin pathway in response to the emission of green leaf volatiles can recruit the natural enemy of aphids. These results demonstrate that VOCs may help prevent plant disease and insect damage by eliciting induced resistance, even in open fields. PMID:23698768

  9. Two Volatile Organic Compounds Trigger Plant Self-Defense against a Bacterial Pathogen and a Sucking Insect in Cucumber under Open Field Conditions

    PubMed Central

    Song, Geun Cheol; Ryu, Choong-Min

    2013-01-01

    Systemic acquired resistance (SAR) is a plant self-defense mechanism against a broad-range of pathogens and insect pests. Among chemical SAR triggers, plant and bacterial volatiles are promising candidates for use in pest management, as these volatiles are highly effective, inexpensive, and can be employed at relatively low concentrations compared with agrochemicals. However, such volatiles have some drawbacks, including the high evaporation rate of these compounds after application in the open field, their negative effects on plant growth, and their inconsistent levels of effectiveness. Here, we demonstrate the effectiveness of volatile organic compound (VOC)-mediated induced resistance against both the bacterial angular leaf spot pathogen, Pseudononas syringae pv. lachrymans, and the sucking insect aphid, Myzus persicae, in the open field. Using the VOCs 3-pentanol and 2-butanone where fruit yields increased gave unexpectedly, a significant increase in the number of ladybird beetles, Coccinella septempunctata, a natural enemy of aphids. The defense-related gene CsLOX was induced by VOC treatment, indicating that triggering the oxylipin pathway in response to the emission of green leaf volatiles can recruit the natural enemy of aphids. These results demonstrate that VOCs may help prevent plant disease and insect damage by eliciting induced resistance, even in open fields. PMID:23698768

  10. Beauveria bassiana, Metarhizium anisopliae, and Metarhizium anisopliae var. acridum conidia: tolerance to imbibitional damage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When dry fungal cells are immersed in water, rapid imbibition (water uptake) may compromise the plasma membrane, killing the cell. This study investigated the impact of imbibitional damage (measured in terms of reduced viability) on Beauveria bassiana (Bb), Metarhizium anisopliae (Ma) and M. anisop...

  11. Allergenic extracts from Metarhizium canisopliae: obtainment and characterization.

    PubMed

    Barbieri, R T; Croce, J; Gandra, R F; Gagete, E; Paula, C R; Gambale, W

    2005-01-01

    Metarhizium anisopliae is used as a biopesticide for insects that damage agricultural plantations like sugar cane and forage plants. In a previous study the sensitization to this fungus of asthmatic patients coming from sugar cane areas was showed. The aims of this work were: to compare crude extracts obtained with Tris-HCl and Coca liquid from several growth phases of M. anisopliae concerning the total content of proteins and their electrophoretic analysis profile; to evaluate in vivo allergic sensitization in Balb/c mice and allergic patients from a sugar cane area, and to characterize the allergenic fractions in the sera of patients positive for the prick test by means of Western-blotting. The extract obtained with Coca liquid on the 16th day was the one that presented the greatest number of proteic fractions, including all those present in the other extracts. Twelve fractions were verified in this extract with approximate molecular weights from 94 to 14 kDa. The allergenicity of the extract obtained on the 16th day was proven by the production of IgE antibodies in Balb/c mice, with titres of 200. Prick tests carried out with the extract of the 16th day in 79 atopic individuals (from sugar cane area), 35 atopic individuals (from urban area) and 11 non- atopic individuals showed respective positivity of 29%, 9% and 0%. The allergenic characterization in vitro was performed by means of Western blotting, and the fractions that reacted with the positive individuals' sera were those of approximate molecular weights of 67 kDa (95%); 20 kDa (55%); 94 kDa (36%); 34 and 36 kDa (23%); 43 and 48 kDa (14%); 16 kDa (9%) and 54kDa (5%). It was concluded that the crude allergenic extract, obtained with Coca liquid from the 16th day growth of Metarhizium anisopliae, contains allergenic fractions and can be used in diagnostic screening tests. PMID:16047714

  12. EFFECT OF SEVERAL STRESS FACTORS ON THE SUSCEPTIBILITY OF THE PREDATORY INSECT, CHRYSOPERIA CARNEA, TO THE FUNGAL PATHOGEN BEAUVERIA BASSIANA

    EPA Science Inventory

    Temperature, starvation, and nutrition stresses, applied singly and in combination, significantly affected the susceptibility of chrysoperla carnea to Beauveria bassiana and varied in effectiveness according to insect age and gender. he nutrition stress caused the most significan...

  13. Insect E-probe Diagnostic Nucleic acid Analysis (EDNA): the application of a novel bioinformatic tool to detection of vectors and pathogens in individual insect and simulated insect trap metagenomes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant pathogen detection takes many forms. In simple cases, researchers are attempting to detect a known pathogen from a known host utilizing targeted nucleic acid or antigenic assays. However, in more complex scenarios researchers may not know the identity of a pathogen, or they may need to screen ...

  14. Possible climate warming effects on vegetation, forests, biotic (insect, pathogene) disturbances and agriculture in Central Siberia for 1960- 2050

    NASA Astrophysics Data System (ADS)

    Tchebakova, N. M.; Parfenova, E. I.; Soja, A. J.; Lysanova, G. I.; Baranchikov, Y. N.; Kuzmina, N. A.

    2012-04-01

    Regional Siberian studies have already registered climate warming over the last half a century (1960-2010). Our analysis showed that winters are already 2-3°C warmer in the north and 1-2°C warmer in the south by 2010. Summer temperatures increased by 1°C in the north and by 1-2°C in the south. Change in precipitation is more complicated, increasing on average 10% in middle latitudes and decreasing 10-20% in the south, promoting local drying in already dry landscapes. Our goal was to summarize results of research we have done for the last decade in the context of climate warming and its consequences for biosystems in Central Siberia. We modeled climate change effects on vegetation shifts, on forest composition and agriculture change, on the insect Siberian moth (Dendrolimus suprans sibiricus Tschetv) and pathogene (Lophodermium pinastri Chev) ranges in Central Siberia for a century (1960-2050) based on historical climate data and GCM-predicted data. Principal results are: In the warmer and drier climate projected by these scenarios, Siberian forests are predicted to decrease and shift northwards and forest-steppe and steppe ecosystems are predicted to dominate over 50% of central Siberia due to the dryer climate by 2080. Permafrost is not predicted to thaw deep enough to sustain dark (Pinus sibirica, Abies sibirica, and Picea obovata) taiga. Over eastern Siberia, larch (Larix dahurica) taiga is predicted to continue to be the dominant zonobiome because of its ability to withstand continuous permafrost. The model also predicts new temperate broadleaf forest and forest-steppe habitats; At least half of central Siberia is predicted to be climatically suitable for agriculture at the end of the century although potential croplands would be limited by the availability of suitable soils agriculture in central Siberia would likely benefit from climate warming Crop production may twofold increase as climate warms during the century; traditional crops (grain, potato

  15. INFECTIVITY OF METARHIZIUM ANISOPLIAE IN GRASS SHRIMP EMBRYOS

    EPA Science Inventory

    Developing embryos of the estuarine grass shrimp, Palaemonetes pugio, were exposed to Metarhizium anisopliae conidiospores. Attachment of conidiospores was often followed by germination and outgrowth on embryo surface. Penetration of the embryonic envelopes by M. anisopliae allow...

  16. Isolation, pathogenicity and disinfection of Staphylococcus aureus carried by insects in two public hospitals of Vitória da Conquista, Bahia, Brazil.

    PubMed

    Oliveira, Pollianna S; Souza, Simone G; Campos, Guilherme B; da Silva, Danilo C C; Sousa, Daniel S; Araújo, Suerda P F; Ferreira, Laiziane P; Santos, Verena M; Amorim, Aline T; Santos, Angelita M O G; Timenetsky, Jorge; Cruz, Mariluze P; Yatsuda, Regiane; Marques, Lucas M

    2014-01-01

    Currently, hospital infection is a serious public health problem, and several factors may influence the occurrence of these infections, including the presence of insects, which are carriers of multidrug-resistant bacterial species. The aim of this study was to isolate staphylococci carried by insects in two public hospitals of Vitoria da Conquista, Bahia and to identify the resistance profile, pathogenicity and efficacy of disinfection of the premises. A total of 91 insects were collected in 21 strategic points of these hospitals, and 32 isolated strains of Staphylococcus aureus were isolated. Based on antibiogram and Minimum Inhibitory Concentration results, 95% of these strains were susceptible to oxacillin. These strains were also evaluated for the presence of resistance genes encoding resistance to oxacillin/methicillin by polymerase chain reaction, but the sample was negative for this gene. Pathogenicity tests were performed in vitro biofilm formation induced by glucose, where it was found that eight (27.58%) strains were classified as biofilm producers and 21 (72.4%) as stronger producers. In addition, we performed PCR for their virulence genes: Sea (enterotoxin A), SEB (B), Sec (C), PVL (Panton-Valentine Leukocidin), ClfA (clumping factor A) and Spa (protein A). Of these, Sea, Spa PVL were positive in 7 (21.8%), 2 (6.3%) and 1 (3.1%) samples, respectively. The analysis of cytokine induction in the inflammatory response of J774 macrophages by isolates from the two hospitals did not show statistical difference at the levels of IL-6, TNF-α, IL-1 and IL-10 production. In addition, we verified the antimicrobial activity of disinfecting agents on these strains, quaternary ammonium, 0.5% sodium hypochlorite, 1% sodium hypochlorite, 2% sodium hypochlorite, 2% glutaraldehyde, Lysoform(®), 70% alcohol solution of chlorhexidine digluconate, 2% peracetic acid, and 100% vinegar. Resistance was seen in only for the following two disinfectants: 70% alcohol in 31 (96

  17. The Ifchit1 chitinase gene acts as a critical virulence factor in the insect pathogenic fungus Isaria fumosorosea.

    PubMed

    Huang, Zhen; Hao, Yongfen; Gao, Tianni; Huang, Yü; Ren, Shunxiang; Keyhani, Nemat O

    2016-06-01

    The filamentous fungus, Isaria fumosorosea, is a promising insect biological control agent. Chitinases have been implicated in targeting insect cuticle structures, with biotechnological potential in insect and fungal control. The I. fumosorosea chitinase gene, Ifchit1, was isolated and determined to encode a polypeptide of 423 amino acids (46 kDa, pI = 6.53), present as a single copy in the I. fumosorosea genome. A split marker transformation system was developed and used to construct an Ifchit1 gene knockout. The ΔIfchit1 strain displayed minor alterations in mycelial growth on diverse media at 26 °C compared to the wild type and complemented (ΔIfchit1::Ifchit1) strains; however, colony morphology was affected, and the mutant strain had a temperature sensitive phenotype (32 °C). Although sporulation was delayed for the mutant, overall conidial production was almost twice than that of wild type. Biochemical assays indicated decreased chitinase activity during growth in Czapek-Dox liquid media for the ΔIfchit1 strain. Insect bioassays using diamondback moth, Plutella xylostella, larvae revealed decreased infectivity, i.e., increased LC 50 (threefold to fourfold) and a significantly delayed time to death, LT 50 from 3 to 6 days, for the ΔIfchit1 strain compared to the wild type and complemented strains. These data indicate an important role for the Ifchit1 chitinase as a virulence factor in I. fumosorosea. PMID:26910039

  18. beta-1,3-Glucan recognition by an insect pathogen recognition domain causes self-association of protein: carbohydrate complex

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In response to invading microorganisms, insect beta-1,3-glucan recognition protein (beta-GRP), a soluble receptor in the hemolymph, binds to the surfaces of bacteria and fungi and activates serine protease cascades associated with the prophenoloxidase (proPO) and Toll pathways; it also agglutinates ...

  19. Pathogenicity, characterization and comparative virulence of Rhizoctonia spp. from insect-galled roots of Lepidium draba in Europe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The association of Rhizoctonia spp. with insect-damaged and diseased tissue of the invasive perennial Lepidium draba was documented throughout the range of L. draba that was surveyed in Europe, including Hungary, Austria, Switzerland and France. Samples that could be both maintained under cooled con...

  20. Altered Immunity in Crowded Locust Reduced Fungal (Metarhizium anisopliae) Pathogenesis

    PubMed Central

    Wang, Yundan; Yang, Pengcheng; Cui, Feng; Kang, Le

    2013-01-01

    The stress of living conditions, similar to infections, alters animal immunity. High population density is empirically considered to induce prophylactic immunity to reduce the infection risk, which was challenged by a model of low connectivity between infectious and susceptible individuals in crowded animals. The migratory locust, which exhibits polyphenism through gregarious and solitary phases in response to population density and displays different resistance to fungal biopesticide (Metarhizium anisopliae), was used to observe the prophylactic immunity of crowded animals. We applied an RNA-sequencing assay to investigate differential expression in fat body samples of gregarious and solitary locusts before and after infection. Solitary locusts devoted at least twice the number of genes for combating M. anisopliae infection than gregarious locusts. The transcription of immune molecules such as pattern recognition proteins, protease inhibitors, and anti-oxidation proteins, was increased in prophylactic immunity of gregarious locusts. The differentially expressed transcripts reducing gregarious locust susceptibility to M. anisopliae were confirmed at the transcriptional and translational level. Further investigation revealed that locust GNBP3 was susceptible to proteolysis while GNBP1, induced by M. anisopliae infection, resisted proteolysis. Silencing of gnbp3 by RNAi significantly shortened the life span of gregarious locusts but not solitary locusts. By contrast, gnbp1 silencing did not affect the life span of both gregarious and solitary locusts after M. anisopliae infection. Thus, the GNBP3-dependent immune responses were involved in the phenotypic resistance of gregarious locusts to fungal infection, but were redundant in solitary locusts. Our results indicated that gregarious locusts prophylactically activated upstream modulators of immune cascades rather than downstream effectors, preferring to quarantine rather than eliminate pathogens to conserve energy

  1. Pathogen growth in insect hosts: inferring the importance of different mechanisms using stochastic models and response-time data.

    PubMed

    Kennedy, David A; Dukic, Vanja; Dwyer, Greg

    2014-09-01

    Pathogen population dynamics within individual hosts can alter disease epidemics and pathogen evolution, but our understanding of the mechanisms driving within-host dynamics is weak. Mathematical models have provided useful insights, but existing models have only rarely been subjected to rigorous tests, and their reliability is therefore open to question. Most models assume that initial pathogen population sizes are so large that stochastic effects due to small population sizes, so-called demographic stochasticity, are negligible, but whether this assumption is reasonable is unknown. Most models also assume that the dynamic effects of a host's immune system strongly affect pathogen incubation times or "response times," but whether such effects are important in real host-pathogen interactions is likewise unknown. Here we use data for a baculovirus of the gypsy moth to test models of within-host pathogen growth. By using Bayesian statistical techniques and formal model-selection procedures, we are able to show that the response time of the gypsy moth virus is strongly affected by both demographic stochasticity and a dynamic response of the host immune system. Our results imply that not all response-time variability can be explained by host and pathogen variability, and that immune system responses to infection may have important effects on population-level disease dynamics. PMID:25141148

  2. Occurrence and Prevalence of Insect Pathogens in Populations of the Codling Moth, Cydia pomonella L.: A Long-Term Diagnostic Survey

    PubMed Central

    Zimmermann, Gisbert; Huger, Alois M.; Kleespies, Regina G.

    2013-01-01

    About 20,550 larvae, pupae and adults of the codling moth, Cydia pomonella L., were diagnosed for pathogens during long-term investigations (1955–2012) at the Institute for Biological Control in Darmstadt, Germany. The prevailing entomopathogens diagnosed in these studies were insect pathogenic fungi, especially Beauveria bassiana and Isaria farinosa, the microsporidium, Nosema carpocapsae, the Cydia pomonella granulovirus (CpGV), as well as mostly undetermined bacteria. While the CpGV was observed exclusively in larvae and pupae from laboratory colonies or from field experiments with this virus, entomopathogenic fungi were most frequently diagnosed in last instars in autumn and in diapausing larvae and pupae in spring. B. bassiana was identified as the major fungal pathogen, causing larval prevalences of 0.9% to 100% (mean, about 32%). During prognostic long-term studies in larvae and adults of C. pomonella, N. carpocapsae was diagnosed in codling moth populations from various locations in Germany. The mean prevalence generally ranged between 20% and 50%. Experiments revealed that the fecundity and fertility of microsporidia-infected female adults were significantly reduced compared to healthy ones. The results underpin the importance of naturally occurring microbial antagonists and represent a base for further ecological studies on developing new or additional biological and integrated control strategies. PMID:26462428

  3. A Recombinant AeDNA Containing the Insect-Specific Toxin, BmK IT1, Displayed an Increasing Pathogenicity on Aedes albopictus

    PubMed Central

    Gu, Jin-Bao; Dong, Yun-Qiao; Peng, Hong-Juan; Chen, Xiao-Guang

    2010-01-01

    The Aedes aegypti densovirus (AeDNV) has previously shown potential in mosquito control. To improve its efficacy as a biopesticide, the gene for an excitatory insect-specific toxin from Buthus martensii Karsch (BmK IT1) was inserted into the AeDNV genome and cloned into pUCA plasmid. The coding sequence for green fluorescent protein was ligated to the C-terminus of the BmK IT1 gene as a screening marker. Recombinant and helper plasmids were cotransfected into C6/36 cells; wild-type viruses were the controls. The recombinant viruses were identified and quantified by real-time polymerase chain reaction and exposed to Ae. albopictus larvae for the evaluation of its bioinsecticidal activity. LT50 and LD50 bioassays showed that the recombinant AeDNV had stronger and faster pathogenic effects on Ae. albopictus than the wild-type virus. This is the first report on the recombinant AeDNA containing the insect-specific toxin, BmK IT1, which may be used to develop a novel type of insecticide. PMID:20810829

  4. Bioassay assessment of metarhizium anisopliae (metchnikoff) sorokin (deuteromycota: hyphomycetes) against Oncometopia facialis (signoret) (hemiptera: cicadellidae)

    PubMed Central

    Pria Júnior, Wolney Dalla; Lacava, Paulo Teixeira; Messias, Claudio Luiz; Azevedo, João Lúcio; Lacava, Pedro Magalhães

    2008-01-01

    Citrus Variegated Chlorosis (CVC) is an economically important, destructive disease in Brazil and is caused by Xylella fastidiosa and transmitted by sharpshooter insects. In this study, the efficacy of the fungus Metarhizium anisopliae in controlling the sharpshooter Oncometopia facialis was studied by bioassay conditions. In the bioassay, insects were sprayed with a suspension containing 5 X 107 conidia mL-1. Adults captured in the field were treated in groups of 10 in a total of 11 replications per treatment. Significant differences between the natural mortality and the mortality of insects treated with the fungus were observed 6 days after inoculations (P<0.05). These significant differences increased until 10 days after treatment. The fungus caused 87.1% mortality, with the LT50 varying from 5 to 6 days. The LC50 was 1.2 X 106 conidia mL-1, varying from 7.7 X 105 to 2 X 106 conidia mL-1. The results showed that the sharpshooter O. facialis was susceptible to the entomopathogenic action of M. anisopliae in controlled condition during bioassay. PMID:24031192

  5. The combination of the entomopathogenic fungus Metarhizium anisopliae with the insecticide Imidacloprid increases virulence against the dengue vector Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    2011-01-01

    Background Dengue fever transmitted by the mosquito Aedes aegypti, is one of the most rapidly spreading insect borne diseases, stimulating the search for alternatives to current control measures. The dengue vector A. aegypti has received less attention than anophelene species, although more than 2.5 billion people are at risk of infection worldwide. Entomopathogenic fungi are emerging as potential candidates for the control of mosquitoes. Here we continue our studies on the pathogenicity of the entomopathogenic fungus Metarhizium anisopliae against adult A. aegypti females. With the aim of further reducing mean survival times of A. aegypti exposed to fungus impregnated surfaces, a sub-lethal concentration of the neonicotinoid insecticide Imidacloprid (IMI) was added to fungal suspensions. Results A sub-lethal concentration of IMI that did not significantly alter the daily survival rates or mean survival percentages of mosquitoes was identified to be 0.1 ppm. This sub-lethal concentration was combined with M. anisopliae conidia (1 × 109 conidia mL-1). Both the combined treatment and the conidia alone were able to reduce the survival of A. aegypti compared with untreated or IMI treated mosquitoes. Importantly, mosquito survival following exposure to the combined treatment for 6 and 12 hrs was significantly reduced when compared with mosquitoes exposed to conidia alone. Conclusions This is the first time that a combination of an insecticide and an entomopathogenic fungus has been tested against A. aegypti. Firstly, the study showed the potential of IMI as an alternative to the currently employed pyrethroid adulticides. Secondly, as an alternative to applications of high concentrations of chemical insecticides, we suggest that adult A. aegypti could be controlled by surface application of entomopathogenic fungi and that the efficiency of these fungi could be increased by combining the fungi with ultra-low concentrations of insecticides, resulting in higher mortality

  6. A novel mitochondrial membrane protein, Ohmm, limits fungal oxidative stress resistance and virulence in the insect fungal pathogen Beauveria bassiana.

    PubMed

    He, Zhangjiang; Zhang, Suhong; Keyhani, Nemat O; Song, Yulin; Huang, Shuaishuai; Pei, Yan; Zhang, Yongjun

    2015-11-01

    The Hog1 mitogen-activated protein (MAP) kinase regulates environmental stress responses and virulence in the entomopathogenic fungus Beauveria bassiana. To further characterize this pathway, we constructed a subtraction library enriched for genes regulated by Hog1. One targeted gene, encoding a novel membrane protein, Ohmm (oxidative homeostasis membrane-protein-mitochondria), was uniquely identified as being downregulated in the ΔHog1 background during growth under non-stress and osmotic stress conditions, but upregulated under oxidative stress. Ohmm was an experimentally validated flavin-binding protein and targeted to the mitochondria. Deletion of Ohmm resulted in increased oxidative stress resistance, whereas overexpression caused an opposite phenotype. The ΔOhmm showed accumulation of reactive oxygen species with alterations in cell wall composition and compatible solute accumulation evident as compared with the wild type parent. Conidiation was reduced > 80%; however, conidia produced by the ΔOhmm strain germinated significantly faster than wild type cells. Insect bioassays using the greater wax moth revealed increased virulence for the ΔOhmm strain in both topical and intrahemocoel injection assays, indicating a negative effect of the presence of Ohmm with respect to pathogenesis. As predicted from our characterization, deletion of Ohmm in a ΔHog1 background rescued its oxidative sensitivity phenotype, confirming that Ohmm acts downstream of the Hog1 MAP-kinase. PMID:25403093

  7. Interaction between TATA-Binding Protein (TBP) and Multiprotein Bridging Factor-1 (MBF1) from the Filamentous Insect Pathogenic Fungus Beauveria bassiana

    PubMed Central

    Song, Chi; Ortiz-Urquiza, Almudena; Ying, Sheng-Hua; Zhang, Jin-Xia; Keyhani, Nemat O.

    2015-01-01

    TATA-binding protein (TBP) is a ubiquitous component of eukaryotic transcription factors that acts to nucleate assembly and position pre-initiation complexes. Multiprotein bridging factor 1 (MBF1) is thought to interconnect TBP with gene specific transcriptional activators, modulating transcriptional networks in response to specific signal and developmental programs. The insect pathogen, Beauveria bassiana, is a cosmopolitan fungus found in most ecosystems where it acts as an important regulator of insect populations and can form intimate associations with certain plants. In order to gain a better understanding of the function of MBF1 in filamentous fungi, its interaction with TBP was demonstrated. The MBF1 and TBP homologs in B. bassiana were cloned and purified from a heterologous E. coli expression system. Whereas purified BbTBP was shown to be able to bind oligonucleotide sequences containing the TATA-motif (Kd ≈ 1.3 nM) including sequences derived from the promoters of the B. bassiana chitinase and protease genes. In contrast, BbMBF1 was unable to bind to these same target sequences. However, the formation of a ternary complex between BbMBF1, BbTBP, and a TATA-containing target DNA sequence was seen in agarose gel electrophoretic mobility shift assays (EMSA). These data indicate that BbMBF1 forms direct interactions with BbTBP, and that the complex is capable of binding to DNA sequences containing TATA-motifs, confirming that BbTBP can link BbMBF1 to target sequences as part of the RNA transcriptional machinery in fungi. PMID:26466369

  8. Interaction between TATA-Binding Protein (TBP) and Multiprotein Bridging Factor-1 (MBF1) from the Filamentous Insect Pathogenic Fungus Beauveria bassiana.

    PubMed

    Song, Chi; Ortiz-Urquiza, Almudena; Ying, Sheng-Hua; Zhang, Jin-Xia; Keyhani, Nemat O

    2015-01-01

    TATA-binding protein (TBP) is a ubiquitous component of eukaryotic transcription factors that acts to nucleate assembly and position pre-initiation complexes. Multiprotein bridging factor 1 (MBF1) is thought to interconnect TBP with gene specific transcriptional activators, modulating transcriptional networks in response to specific signal and developmental programs. The insect pathogen, Beauveria bassiana, is a cosmopolitan fungus found in most ecosystems where it acts as an important regulator of insect populations and can form intimate associations with certain plants. In order to gain a better understanding of the function of MBF1 in filamentous fungi, its interaction with TBP was demonstrated. The MBF1 and TBP homologs in B. bassiana were cloned and purified from a heterologous E. coli expression system. Whereas purified BbTBP was shown to be able to bind oligonucleotide sequences containing the TATA-motif (Kd ≈ 1.3 nM) including sequences derived from the promoters of the B. bassiana chitinase and protease genes. In contrast, BbMBF1 was unable to bind to these same target sequences. However, the formation of a ternary complex between BbMBF1, BbTBP, and a TATA-containing target DNA sequence was seen in agarose gel electrophoretic mobility shift assays (EMSA). These data indicate that BbMBF1 forms direct interactions with BbTBP, and that the complex is capable of binding to DNA sequences containing TATA-motifs, confirming that BbTBP can link BbMBF1 to target sequences as part of the RNA transcriptional machinery in fungi. PMID:26466369

  9. Interplay between calcineurin and the Slt2 MAP-kinase in mediating cell wall integrity, conidiation and virulence in the insect fungal pathogen Beauveria bassiana.

    PubMed

    Huang, Shuaishuai; He, Zhangjiang; Zhang, Shiwei; Keyhani, Nemat O; Song, Yulin; Yang, Zhi; Jiang, Yahui; Zhang, Wenli; Pei, Yan; Zhang, Yongjun

    2015-10-01

    The entomopathogenic fungus, Beauveria bassiana, is of environmental and economic importance as an insect pathogen, currently used for the biological control of a number of pests. Cell wall integrity and conidiation are critical parameters for the ability of the fungus to infect insects and for production of the infectious propagules. The contribution of calcineurin and the Slt2 MAP kinase to cell wall integrity and development in B. bassiana was investigated. Gene knockouts of either the calcineurin CNA1 subunit or the Slt2 MAP kinase resulted in decreased tolerance to calcofluor white and high temperature. In contrast, the Δcna1 strain was more tolerant to Congo red but more sensitive to osmotic stress (NaCl, sorbitol) than the wild type, whereas the Δslt2 strain had the opposite phenotype. Changes in cell wall structure and composition were seen in the Δslt2 and Δcna1 strains during growth under cell wall stress as compared to the wild type. Both Δslt2 and Δcna1 strains showed significant alterations in growth, conidiation, and viability. Elevation of intracellular ROS levels, and decreased conidial hydrophobicity and adhesion to hydrophobic surfaces, were also seen for both mutants, as well as decreased virulence. Under cell wall stress conditions, inactivation of Slt2 significantly repressed CN-mediated phosphatase activity suggesting some level of cross talk between the two pathways. Comparative transcriptome profiling of the Δslt2 and Δcna1 strains revealed alterations in the expression of distinct gene sets, with overlap in transcripts involved in cell wall integrity, stress response, conidiation and virulence. These data illustrate convergent and divergent phenotypes and targets of the calcineurin and Slt2 pathways in B. bassiana. PMID:26319315

  10. Laboratory evaluation of Beauveria bassiana and Metarhizium anisopliae in the control of Haemaphysalis qinghaiensis in China.

    PubMed

    Ren, Qiaoyun; Chen, Ze; Luo, Jin; Liu, Guangyuan; Guan, Guiquan; Liu, Zhijie; Liu, Aihong; Li, Youquan; Niu, Qingli; Liu, Junlong; Yang, Jifei; Han, Xueqing; Yin, Hong; Luo, Jianxun

    2016-06-01

    Haemaphysalis qinghaiensis, a prevalent tick species in China, is an ectoparasite that preferentially infests small ruminants and can transmit Theileria sp. and Babesia sp. In this study, we evaluated the pathogenicity of individual and mixed infections of the fungi Beauveria bassiana and Metarhizium anisopliae to H. qinghaiensis nymphs. The estimated LC50 for ticks immersed in solutions of B. bassiana, M. anisopliae and a mixture thereof were: 5.88056 × 10(4), 2.65 × 10(4), and 2.85 × 10(4) conidia mL(-1) respectively, and the nymphal mortality ranged from 52 to 100 %. Thus, these results suggest a potential approach for the biocontrol of H. qinghaiensis. PMID:27071674

  11. Serinocyclins A and B, Cyclic Heptapeptides from Metarhizium anisopliae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two new cyclic heptapeptides, serinocyclins A (1) and B (2), were isolated from conidia of the entomopathogenic fungus Metarhizium anisopliae. Structures were elucidated by a combination of mass spectrometric, NMR, and X-ray diffraction techniques. Serinocyclin A (1) contains three serine units, a...

  12. CONTROL OF WIREWORM (ELATERIDAE) IN POTATOES WITH MICROBIAL METARHIZIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Technical grade, liquid and granular formulations of Metarhizium anisopliae F52 were evaluated for wireworm control in small plots of potatoes at two sites in 2006. In-furrow treatments of three different formulations on day of planting: an emulsifiable concentrate (EC) diluted in water, a technica...

  13. Metacridamides A and B from the biocontrol fungus metarhizium acridum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metarhizium acridum, an entomopathogenic fungus, has been commercialized and used successfully for biocontrol of grasshopper pests in Africa and Australia. As part of an effort to catalog the secondary metabolites of this fungus we discovered that its conidia produce two novel 17-membered macrocycl...

  14. Occurrence of Metarhizium spp in central Brazilian soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The biodiversity of entomopathogenic fungi in tropical ecosystems is still little investigated, and the objective of this study was to isolate and identify fungi of the entomopathogenic genus Metarhizium (Hypocreales: Clavicipitaceae) present in undisturbed soils of Central Brazilian Cerrado. A tota...

  15. A natural fungal infection of a sylvatic cockroach with Metarhizium blattodeae sp. nov., a member of the M. flavoviride species complex.

    PubMed

    Montalva, Cristian; Collier, Karin; Rocha, Luiz Fernando Nunes; Inglis, Peter Ward; Lopes, Rogério Biaggioni; Luz, Christian; Humber, Richard A

    2016-05-01

    A wild, forest-dwelling cockroach from the subfamily Ectobiidae (order Blattodea) in a nature reserve in Cavalcante, in the state of Goiás, Brazil, was found to be infected by a new, genetically distinct species in the Metarhizium flavoviride species complex that we describe here as Metarhizium blattodeae. The status of this fungus as a new species is supported by both multigenic sequence comparisons and protein profiles generated by MALDI-TOF (matrix-assisted laser desorption/ionization time-of-flight) mass spectrometry. This is one of the first reports of a naturally occurring fungal pathogen affecting any sylvatic (forest-dwelling) cockroach from any part of the world. M. blattodeae caused up to 96 % mortality of Periplaneta americana nymphs (a serious peridomestic cockroach species) after 10 d. PMID:27109363

  16. Effects of associated bacteria on the pathogenicity and reproduction of the insect-parasitic nematode Rhabditis blumi (Nematoda: Rhabditida).

    PubMed

    Park, Hae Woong; Kim, Yong Ook; Ha, Jae-Seok; Youn, Sung Hun; Kim, Hyeong Hwan; Bilgrami, Anwar L; Shin, Chul Soo

    2011-09-01

    Three bacteria, Alcaligenes faecalis , Flavobacterium sp., and Providencia vermicola , were isolated from dauer juveniles of Rhabditis blumi . The pathogenic effects of the bacteria against 4th instar larvae of Galleria mellonella were investigated. Providencia vermicola and Flavobacterium sp. showed 100% mortality at 48 h after haemocoelic injection, whereas A. faecalis showed less than 30% mortality. Dauer juveniles showed 100% mortality against G. mellonella larvae, whereas axenic juveniles, which do not harbor associated bacteria, exhibited little mortality. All of the associated bacteria were used as a food source for nematode growth, and nematode yield differed with bacterial species. Among the bacterial species, P. vermicola was most valued for nematode yield, showing the highest yield of 5.2 × 10(4) nematodes/mL in the plate. In bacterial cocultures using two of the three associated bacteria, one kind stimulated the other. The highest total bacterial yield of 12.6 g/L was obtained when the inoculum ratio of P. vermicola to A. faecalis was 10:1. In air-lift bioreactors, the nematode growth rate increased with an increasing level of dissolved oxygen. The maximum nematode yield of 1.75 × 10(5) nematodes/mL was obtained at 192 h with an aeration rate of 6 vvm. PMID:21867444

  17. Safety and acquisition potential of Metarhizium anisopliae in entomovectoring with bumble bees, Bombus terrestris.

    PubMed

    Smagghe, Guy; De Meyer, Laurens; Meeus, Ivan; Mommaerts, Veerle

    2013-02-01

    In the context of integrated pest management with biological control and reduced pesticide use, dissemination of entomopathogenic fungi with insects has the potency to protect crops and specifically their flowers against pests and diseases. But before implementation of such entomovectoring system, a measurement of risks of the microbial biocontrol agent toward the vectoring insect is crucial. The essential contributions of this project are that 1) exposure of bumble bees, Bombus terrestris (L.) to powder containing 10(7) spores of the commercial biocontrol agent Metarhizium anisopliae strain F52 (Biol020) per gram, was safe; and 2) that when bumble bees had walked through this spore concentration (10(7) spores per gram) in a dispenser, their body carried 9.3 +/- 1 x 10(6) spores/bumble bee, and this was still 2.6 10(6) spores after a flight of 60 s, representing the average time to fly from the dispenser to the crop flowers. 3) In contrast, a 100-fold higher spore concentration (10(9) spores per gram powder) was highly toxic and the acquisition on the bumble bee body was only 2.5 times higher. Based on these data, future studies can start investigating the protection efficacy of this entomovector system with M. anisopliae and bumble bees without harming the vector and with a loading of the vector considered enough to obtain a good inoculation into and protection of the flowers. PMID:23448041

  18. Production of Conidia by the Fungus Metarhizium anisopliae Using Solid-State Fermentation.

    PubMed

    Loera-Corral, Octavio; Porcayo-Loza, Javier; Montesinos-Matias, Roberto; Favela-Torres, Ernesto

    2016-01-01

    This chapter describes the production of conidia by Metarhizium anisopliae using solid-state fermentation. Before production of conidia, procedures for strains conservation, reactivation, and propagation are essential in order to provide genetic stability of the strains. The strain is conserved in freeze-dried vials and then reactivated through insect inoculation. Rice is used as a substrate for the conidia production in two different bioreactors: plastic bags and tubular bioreactor. The CO2 production in the tubular bioreactors is measured with a respirometer; this system allows calculating indirect growth parameters as lag time (tlag) (25-35 h), maximum rate of CO2 production (rCO2 max) (0.5-0.7 mg/gdm h), specific rate of CO2 production (μ) (0.10-0.15 1/h), and final CO2 production (CO2) (100-120 mg/gdm). Conidial yield per gram of dry substrate (gdm) should be above 1 × 10(9) conidia/gdm after 10 days of incubation. Germination and viability of conidia obtained after 10 days of incubation should be above 80 % and 75 %, respectively. Bioassays using of Tenebrio molitor as a host insect should yield a final mortality above 80 %. PMID:27565492

  19. Mas5, a homologue of bacterial DnaJ, is indispensable for the host infection and environmental adaptation of a filamentous fungal insect pathogen.

    PubMed

    Wang, Jie; Ying, Sheng-Hua; Hu, Yue; Feng, Ming-Guang

    2016-03-01

    Mas5, a yeast heat shock protein classified to the Hsp40 group, is homologous to bacterial archetype DnaJ but functionally unexplored in filamentous fungi. Here we identify a Mas5 homologue (46.86 kDa) in Beauveria bassiana and show its indispensability for host infection and environmental adaptation of the fungal insect pathogen. The deletion of mas5 caused severe defects in aerial conidiation, conidial germination and submerged blastospore production (mimic to host haemocoel). The deletion mutant lost 100% virulence to Galleria mellonella larvae through normal cuticular penetration (topical inoculation) and 50% through cuticle-bypassing infection (intrahaemocoel injection). It formed no blastospore in vivo after inoculation or only a very few after injection. Its extracellular (cuticle degrading) enzymes and virulence-relating Pr1 proteases were 62% and 32% less active respectively. It became more sensitive to high osmolarity, oxidation, cell-wall perturbation, heat shock and UV-B irradiation. These concurred with reduced contents of intracellular mannitol and trehalose, decreased activities of antioxidant enzymes, impaired cell walls and suppressed transcripts of stress-responsive and virulence-relating genes. All the changes were restored by targeted mas5 complementation. All together, Mas5 is indispensable for the in vitro and in vivo life cycle of B. bassiana by targeting many sets of enzymes/proteins at transcriptional and post-transcriptional levels. PMID:26714790

  20. ASSESSMENT OF A CRUDE FUNGAL (METARHIZIUM ANISOPLIAE) EXTRACT AND IT'S COMPONENTS FOR ALLERGENICITY

    EPA Science Inventory

    ASSESSMENT OF A CRUDE FUNGAL (METARHIZIUM ANISOPLIAE) EXTRACT AND IT'S COMPONENTS FOR ALLERGENICITY. M D W Ward1, M E Viana2, L B Copeland1, and MJ K Selgrade1. 1US EPA, ORD, NHEERL, RTP, NC, USA. 2NCSU, College of Veterinary Medicine, Raleigh, NC, USA.
    Metarhizium anisopli...

  1. Laboratory and field evaluation of Metarhizium anisopliae var. anisopliae for controlling subterranean termites.

    PubMed

    Hussain, A; Ahmed, S; Shahid, M

    2011-01-01

    The efficacy of the Metarhizium anisopliae strain ARSEF 6911 was determined in the laboratory and field against two sugarcane pests, Microtermes obesi Holmgren and Odontotermes obesus Rambur (Termitidae: Isoptera). The susceptibility of both termite species to different conidial suspensions (1 × 10(10), 1 × 10(8), 1 × 10(6) and 1 × 10(4) conidia/ml) was determined in laboratory. All conidial suspensions were able to induce mortality. Termite mortality caused by the fungal suspensions was dose dependent. There were no significant differences in the LT50 values between species. Field evaluation of M. anisopliae alone or in combination with diesel oil and thiamethoxam was carried out in two growing seasons (autumn 2005 and spring 2006) at two sites located in Punjab, Pakistan. Dipping the sugarcane setts in these suspensions was tried to determine their effects on germination and percentage of bud damage to sugarcane setts. All treatments significantly reduced termite infestation compared to the untreated control. The combined treatment of M. anisopliae and diesel oil significantly reduced insect damage by attaining higher germination > 55% and lower bud damage < 5.50% at both sites in both seasons. The results suggest that the application of M. anisopliae and diesel oil in combination might be a useful treatment option for the management of termites in sugarcane. PMID:21584407

  2. Insect immunology and hematopoiesis.

    PubMed

    Hillyer, Julián F

    2016-05-01

    Insects combat infection by mounting powerful immune responses that are mediated by hemocytes, the fat body, the midgut, the salivary glands and other tissues. Foreign organisms that have entered the body of an insect are recognized by the immune system when pathogen-associated molecular patterns bind host-derived pattern recognition receptors. This, in turn, activates immune signaling pathways that amplify the immune response, induce the production of factors with antimicrobial activity, and activate effector pathways. Among the immune signaling pathways are the Toll, Imd, Jak/Stat, JNK, and insulin pathways. Activation of these and other pathways leads to pathogen killing via phagocytosis, melanization, cellular encapsulation, nodulation, lysis, RNAi-mediated virus destruction, autophagy and apoptosis. This review details these and other aspects of immunity in insects, and discusses how the immune and circulatory systems have co-adapted to combat infection, how hemocyte replication and differentiation takes place (hematopoiesis), how an infection prepares an insect for a subsequent infection (immune priming), how environmental factors such as temperature and the age of the insect impact the immune response, and how social immunity protects entire groups. Finally, this review highlights some underexplored areas in the field of insect immunobiology. PMID:26695127

  3. Characterization of Metarhizium species and varieties based on molecular analysis, heat tolerance and cold activity

    USGS Publications Warehouse

    Fernandes, E.K.K.; Keyser, C.A.; Chong, J.P.; Rangel, D.E.N.; Miller, M.P.; Roberts, D.W.

    2010-01-01

    Aims: The genetic relationships and conidial tolerances to high and low temperatures were determined for isolates of several Metarhizium species and varieties. Methods and Results: Molecular-based techniques [AFLP and rDNA (ITS1, ITS2 and 5??8S) gene sequencing] were used to characterize morphologically identified Metarhizium spp. isolates from a wide range of sources. Conidial suspensions of isolates were exposed to wet heat (45 ?? 0??2??C) and plated on potato dextrose agar plus yeast extract (PDAY) medium. After 8-h exposure, the isolates divided clearly into two groups: (i) all isolates of Metarhizium anisopliae var. anisopliae (Ma-an) and Metarhizium from the flavoviride complex (Mf) had virtually zero conidial relative germination (RG), (ii) Metarhizium anisopliae var. acridum (Ma-ac) isolates demonstrated high heat tolerance (c. 70-100% RG). Conidial suspensions also were plated on PDAY and incubated at 5??C for 15 days, during which time RGs for Ma-an and Ma-ac isolates were virtually zero, whereas the two Mf were highly cold active (100% RG). Conclusions: Heat and cold exposures can be used as rapid tools to tentatively identify some important Metarhizium species and varieties. Significance and Impact of the Study: Identification of Metarhizium spp. currently relies primarily on DNA-based methods; we suggest a simple temperature-based screen to quickly obtain tentative identification of isolates as to species or species complexes. ?? 2009 The Society for Applied Microbiology.

  4. Mycetocyte symbiosis in insects.

    PubMed

    Douglas, A E

    1989-11-01

    1. Non-pathogenic microorganisms, known as mycetocyte symbionts, are located in specialized 'mycetocyte' cells of many insects that feed on nutritionally unbalanced or poor diets. The insects include cockroaches, Cimicidae and Lygaeidae (Heteroptera), the Homoptera, Anoplura, the Diptera Pupiparia, some formicine ants and many beetles. 2. Most mycetocyte symbionts are prokaryotes and a great diversity of forms has been described. None has been cultured in vitro and their taxonomic position is obscure. Yeasts have been reported in Cerambycidae and Anobiidae (Coleoptera) and a few planthoppers. They are culturable and those in anobiids have been assigned to the genus Torulopsis. 3. The mycetocyte cells may be associated with the gut, lie free in the abdominal haemocoel or be embedded in the fat body of the insect. The mycetocytes are large polyploid cells which rarely divide and the symbionts are restricted to their cytoplasm. 4. The mycetocyte symbionts are transmitted maternally from one insect generation to the next. In many beetles (Anobiidae, Cerambycidae, Chrysomelidae and cleonine Curculionidae), the microoganisms are smeared onto the eggs and consumed by the hatching larvae. In other insects, they are transferred from mycetocytes to oocytes in the ovary, a process known as transovarial transmission. The details of transmission in the different insect groups vary with the age of the mother (adult, larva or embryo) at which symbiont transfer to the ovary is initiated; whether isolated symbionts or intact mycetocytes are transferred; and the site of entry of symbionts to the egg (anterior, posterior or apolar). 5. Within an individual insect, the biomass of symbionts varies in a regular fashion with age, weight and sex of the insect. Suppression of symbiont growth rate and lysis of 'excess' microorganisms may contribute to the regulation of symbionts (including freshly-isolated preparations of unculturable forms) are used to investigate interactions between the

  5. Multiorganismal Insects: Diversity and Function of Resident Microorganisms

    PubMed Central

    Douglas, Angela E.

    2015-01-01

    All insects are colonized by microorganisms on the insect exoskeleton, in the gut and hemocoel, and within insect cells. The insect microbiota is generally different from microorganisms in the external environment, including ingested food. Specifically, certain microbial taxa are favored by the conditions and resources in the insect habitat, by their tolerance of insect immunity, and by specific mechanisms for their transmission. The resident microorganisms can promote insect fitness by contributing to nutrition, especially by providing essential amino acids, B vitamins, and, for fungal partners, sterols. Some microorganisms protect their insect hosts against pathogens, parasitoids, and other parasites by synthesizing specific toxins or modifying the insect immune system. Priorities for future research include elucidation of microbial contributions to detoxification, especially of plant allelochemicals in phytophagous insects, and resistance to pathogens; as well as their role in among-insect communication; and the potential value of manipulation of the microbiota to control insect pests. PMID:25341109

  6. Susceptibility of Ixodes scapularis (Acari: Ixodidae) to Metarhizium brunneum F52 (Hypocreales: Clavicipitaceae) using three exposure assays in the laboratory.

    PubMed

    Bharadwaj, Anuja; Stafford, Kirby C

    2012-02-01

    An emulsifiable concentrate (EC) and granular (G) formulation of the entomopathogenic fungus, Metarhizium brunneum strain F52 (formerly Metarhizium anisopliae strain F52) were tested against unfed adults and nymphs of Ixodes scapularis Say in the laboratory. Three exposure methods; dip, surface contact, and direct spray application, and three exposure time intervals (3, 30, and 300 min) were used to evaluate the EC formulation. Application rates ranged from 2.6 x 10(2) to 2.6 x 10(8) conidia/cm2. The surface treatment was used for granular formulation with concentrations ranging from 2.3 x 10(5) to 2.3 x 10(7) conidia/cm2 for same three exposure times. Both the EC and G formulations of this fungus were highly pathogenic against I. scapularis adults and nymphs. Logistic regression analysis found formulation, spore concentration, time of exposure, and observation period were significant or highly significant factors influencing tick mortality. For adult I. scapularis, the spray application with the EC formulation of M. brunneum F52 resulted in a lower LC50 (5.9 x 10(4) conidia/cm2) at 30 min than surface exposure to the EC (LC50 = 1.3 x 10(6) conidia/cm2) or G formulation (LC50 = 8.1 x 10(5) conidia/cm2). At higher concentrations, fungal activity was evident in adult I. scapularis held at 5 degrees C suggesting the fungus may provide control in the cooler fall season. While the observed pathogenicity of a fungus against ticks can be dependent upon the bioassay assessment, we found nymphs and adults of I. scapularis to be highly susceptible to M. brunneum F52, regardless of the exposure method used. PMID:22420275

  7. Imbibitional damage in conidia of the entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae, and Metarhizium acridum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When dried organisms are immersed in water, rapid imbibition may cause severe damage to plasma membranes; in unicellular organisms, such damage is usually lethal. This study investigated effects of pre-immersion moisture levels and immersion temperature on imbibitional damage in three insect pathoge...

  8. Analysis and Modeling of Time-Dose-Mortality of Melanoplus sanguinipes, Locusta migratoria migratorioides, and Schistocerca gregaria (Orthoptera: Acrididae) from Beauveria, Metarhizium, and Paecilomyces Isolates from Madagascar

    PubMed

    Nowierski; Zeng; Jaronski; Delgado; Swearingen

    1996-05-01

    A complementary log-log (CLL) model was used to model time-dose-mortality relationships from bioassay tests of 26 fungal isolates mostly from Madagascar, Africa, against three acridid species, all referred to here as "grasshoppers." The fungal pathogens included 15 isolates of Beauveria bassiana, 9 isolates of Metarhizium flavoviridae, and 2 isolates of Paecilomyces spp. Grasshopper species tested included Melanoplus sanguinipes, Locusta migratoria migratorioides, and Schistocerca gregaria. The scaled deviance, mean deviance, Pearson X2 statistic, Hosmer-Lemeshow (H-L) C statistic, and three-dimensional time-dose-mortality graphs were used to assess extra-binomial variation, data points that were potential outliers, conformance of the scaled deviance statistic and Pearson's X2 statistic to a chi2 distribution, and the fit of the CLL model. The H-L C statistic also was found to be useful in showing the goodness of fit of the CLL model for the fungal isolates prior to modeling the extra-binomial variation. After the extra-binomial variation was modeled using Williams' method, the slope from maximum likelihood estimation, modified log(LD50) estimates (which were corrected for background mortality using the CLL model), a dynamic ranking of the log(LD50) values over time, and a three-dimensional plot of time, dose, and mortality of the three grasshopper species were used to evaluate the effectiveness of the fungal isolates. In general, the CLL model provided a rather poor fit of the fungal isolates which had a large number of replicate trials in the bioassay tests (i.e., a large sample size) due to extra-binomial variation. The CLL model provided an excellent fit of the time-dose-mortality relationships of such isolates after the extra-binomial variation was modeled and included in the CLL model. Metarhizium isolates MFV and SP5 were found to be the most virulent isolates tested against M. sanguinipes, followed by Metarhizium isolates: SP8, SP7, SP9, SP6, and SP1, and

  9. Virulence of Entomopathogenic Fungi Metarhizium anisopliae and Paecilomyces fumosoroseus for the Microbial Control of Spodoptera exigua

    PubMed Central

    Han, Ji Hee; Jin, Byung Rae; Lee, Sang Yeob

    2014-01-01

    The beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae) is difficult to control using chemical insecticides because of the development of insecticide resistance. Several pest control agents are used to control the beet armyworm. Entomopathogenic fungi are one of the candidates for eco-friendly pest control instead of chemical control agents. In this study, among various entomopathogenic fungal strains isolated from soil two isolates were selected as high virulence pathogens against larva of beet armyworm. Control efficacy of fungal conidia was influenced by conidia concentration, temperature, and relative humidity (RH). The isolates Metarhizium anisopliae FT83 showed 100% cumulative mortality against second instar larvae of S. exigua 3 days after treatment at 1 × 107 conidia/mL and Paecilomyces fumosoroseus FG340 caused 100% mortality 6 days after treatment at 1 × 104 conidia/mL. Both M. anisopliae FT83 and P. fumosoroseus FG340 effectively controlled the moth at 20~30℃. M. anisopliae FT83 was significantly affected mortality by RH: mortality was 86.7% at 85% RH and 13.4% at 45% RH. P. fumosoroseus FG340 showed high mortality as 90% at 45% RH and 100% at 75% RH 6 days after conidia treatments. These results suggest that P. fumosoroseus FG340 and M. anisopliae FT83 have high potential to develop as a biocontrol agent against the beet armyworm. PMID:25606011

  10. Biocontrol of pigeon tick Argas reflexus (Acari: Argasidae) by entomopathogenic fungus Metarhizium Anisopliae (Ascomycota: Hypocreales)

    PubMed Central

    Tavassoli, Mosa; Pourseyed, Seyed Hassan; Ownagh, Abdulghaffar; Bernousi, Iraj; Mardani, Karim

    2011-01-01

    The pigeon tick Argas reflexus is a pathogen-transmitting soft tick that typically feeds on pigeons, but can also attack humans causing local and systemic reactions. Chemical control is made difficult due to environmental contamination and resistance development. As a result, there is much interest in increasing the role of other strategies like biological control. In this study, the efficacy of three strains (V245, 685 and 715C) of entomopathogenic fungus Metarhizium anisopliae for biological control of three life stages of pigeon tick A. reflexus including eggs, larvae, engorged and unfed adults was investigated under laboratory conditions. Five concentrations of different strains of M. anisopliae ranging from 103 to 107 conidia/ml were used. All fungal strains significantly decreased hatchability of A. reflexus eggs. Strain V245 was the most effective strain on the mortality of larval stage with nearly 100% mortality at the lowest concentration (103 conidia/ml) at 10 days post-inoculation. The mortality rate of both engorged and unfed adult ticks were also increased significantly exposed to different conidial concentrations compared to the control groups (P < 0.05) making this fungus a potential biological control agent of pigeon tick reducing the use of chemical acaricides. PMID:24031777

  11. Molecular characterization and pathogenicity of fungal isolates for use against the small hive beetle (Aethina tumida)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The analysis of DNA sequences from fungal pathogens obtained from cadavers of the small hive beetle (SHB) collected from several apiaries in Florida revealed a mixture of saprobes and two potential primary entomopathogens, Metarhizium anisopliae and Beauveria bassiana. Spray tower bioassays indicate...

  12. Cuticle Fatty Acid Composition and Differential Susceptibility of Three Species of Cockroaches to the Entomopathogenic Fungi Metarhizium anisopliae (Ascomycota, Hypocreales).

    PubMed

    Gutierrez, Alejandra C; Gołębiowski, Marek; Pennisi, Mariana; Peterson, Graciela; García, Juan J; Manfrino, Romina G; López Lastra, Claudia C

    2015-04-01

    Differences in free fatty acids (FFAs) chemical composition of insects may be responsible for susceptibility or resistance to fungal infection. Determination of FFAs found in cuticular lipids can effectively contribute to the knowledge concerning insect defense mechanisms. In this study, we have evaluated the susceptibility of three species of cockroaches to the entomopathogenic fungi Metarhizium anisopliae (Metschnikoff) Sorokin by topical application. Mortality due to M. anisopliae was highly significant on adults and nymphs of Blattella germanica L. (Blattodea: Blattellidae). However, mortality was faster in adults than in nymphs. Adults of Blatta orientalis L. (Blattodea: Blattidae) were not susceptible to the fungus, and nymphs of Blaptica dubia Serville (Blattodea: Blaberidae) were more susceptible to the fungus than adults. The composition of cuticular FFAs in the three species of cockroaches was also studied. The analysis indicated that all of the fatty acids were mostly straight-chain, long-chain, saturated or unsaturated. Cuticular lipids of three species of cockroaches contained 19 FFAs, ranging from C14:0 to C24:0. The predominant fatty acids found in the three studied species of cockroaches were oleic, linoleic, palmitic, and stearic acid. Only in adults of Bl. orientalis, myristoleic acid, γ-linolenic acid, arachidic acid, dihomolinoleic acid, and behenic acid were identified. Lignoceric acid was detected only in nymphs of Bl. orientalis. Heneicosylic acid and docosahexaenoic acid were identified in adults of Ba. dubia. PMID:26470187

  13. Evaluation of Metarhizium brunneum F52 (Hypocreales: Clavicipitaceae) for control of Japanese beetle larvae in turfgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experimental and commercial preparations of Metarhizium brunneum strain F52 were evaluated for control of Japanese beetle Popillia japonica Newman (Coleoptera: Scarbaeidae) larvae (white grubs) in the laboratory and under field conditions. Experimental preparations consisted of granule and liquid f...

  14. Differential allergy responses to Metarhizium anisopliae fungal component extracts in BALB/c mice

    EPA Science Inventory

    Intratracheal aspiration (IA) exposure to Metarhizium anisopliae crude antigen (MACA), which is composed of equal protein amounts of mycelium (MYC), conidia (CON) and inducible proteases/chitinases (IND) extracts/filtrates, has resulted in responses characteristic of human allerg...

  15. Impact of Fungicides on Metarhizium anisopliae in the Rhizosphere, Bulk Soil and In Vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The entomopathogenic fungus Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) is registered in the United States and the Netherlands for black vine weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae) control in container-grown ornamentals. These studies were conducte...

  16. Susceptibility of Apple Clearwing Moth Larvae, Synanthedon myopaeformis (Lepidoptera: Sesiidae) to Beauveria basiana and Metarhizium brunneum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apple clearwing moth larvae, Synanthedon myopaeformis (Lepidoptera: Sessidae) collected from orchards in British Columbia, Canada, were naturally infected with the entomopathogenic fungus, Metarhizium brunneum (Petch). In laboratory bioassays, larvae were susceptible to infection and dose related mo...

  17. Beauveria bassiana and Metarhizium anisopliae endophytically colonize cassava roots following soil drench inoculation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungal entomopathogens Beauveria bassiana and Metarhizium anisopliae were investigated to determine if endophytic colonization could be achieved in cassava. An inoculation method based on drenching the soil around cassava stems using conidial suspensions resulted in endophytic colonization of ca...

  18. Edible insects are the future?

    PubMed

    van Huis, Arnold

    2016-08-01

    The global increase in demand for meat and the limited land area available prompt the search for alternative protein sources. Also the sustainability of meat production has been questioned. Edible insects as an alternative protein source for human food and animal feed are interesting in terms of low greenhouse gas emissions, high feed conversion efficiency, low land use, and their ability to transform low value organic side streams into high value protein products. More than 2000 insect species are eaten mainly in tropical regions. The role of edible insects in the livelihoods and nutrition of people in tropical countries is discussed, but this food source is threatened. In the Western world, there is an increasing interest in edible insects, and examples are given. Insects as feed, in particular as aquafeed, have a large potential. Edible insects have about the same protein content as conventional meat and more PUFA. They may also have some beneficial health effects. Edible insects need to be processed and turned into palatable dishes. Food safety may be affected by toxicity of insects, contamination with pathogens, spoilage during conservation and allergies. Consumer attitude is a major issue in the Western world and a number of strategies are proposed to encourage insect consumption. We discuss research pathways to make insects a viable sector in food and agriculture: an appropriate disciplinary focus, quantifying its importance, comparing its nutritional value to conventional protein sources, environmental benefits, safeguarding food safety, optimising farming, consumer acceptance and gastronomy. PMID:26908196

  19. Insects as alternative hosts for phytopathogenic bacteria.

    PubMed

    Nadarasah, Geetanchaly; Stavrinides, John

    2011-05-01

    Phytopathogens have evolved specialized pathogenicity determinants that enable them to colonize their specific plant hosts and cause disease, but their intimate associations with plants also predispose them to frequent encounters with herbivorous insects, providing these phytopathogens with ample opportunity to colonize and eventually evolve alternative associations with insects. Decades of research have revealed that these associations have resulted in the formation of bacterial-vector relationships, in which the insect mediates dissemination of the plant pathogen. Emerging research, however, has highlighted the ability of plant pathogenic bacteria to use insects as alternative hosts, exploiting them as they would their primary plant host. The identification of specific bacterial genetic determinants that mediate the interaction between bacterium and insect suggests that these interactions are not incidental, but have likely arisen following the repeated association of microorganisms with particular insects over evolutionary time. This review will address the biology and ecology of phytopathogenic bacteria that interact with insects, including the traditional role of insects as vectors, as well as the newly emerging paradigm of insects serving as alternative primary hosts. Also discussed is one case where an insect serves as both host and vector, which may represent a transitionary stage in the evolution of insect-phytopathogen associations. PMID:21251027

  20. Rapid evolution of immune proteins in social insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In social insects the existence of behavioral traits connected to defense against pathogens manifests the importance of pathogens in the evolution of social insects. However, very little is known how the pathogen pressure has affected the evolution of genes involved in the innate immune system in so...

  1. Insect Allergy.

    PubMed

    Lee, Hobart; Halverson, Sara; Mackey, Regina

    2016-09-01

    Insect bites and stings are common. Risk factors are mostly associated with environmental exposure. Most insect bites and stings result in mild, local, allergic reactions. Large local reactions and systemic reactions like anaphylaxis are possible. Common insects that bite or sting include mosquitoes, ticks, flies, fleas, biting midges, bees, and wasps. The diagnosis is made clinically. Identification of the insect should occur when possible. Management is usually supportive. For anaphylaxis, patients should be given epinephrine and transported to the emergency department for further evaluation. Venom immunotherapy (VIT) has several different protocols. VIT is highly effective in reducing systemic reactions and anaphylaxis. PMID:27545732

  2. Bacterial strategies to overcome insect defences.

    PubMed

    Vallet-Gely, Isabelle; Lemaitre, Bruno; Boccard, Frédéric

    2008-04-01

    Recent genetic and molecular analyses have revealed how several strategies enable bacteria to persist and overcome insect immune defences. Genetic and genomic tools that can be used with Drosophila melanogaster have enabled the characterization of the pathways that are used by insects to detect bacterial invaders and combat infection. Conservation of bacterial virulence factors and insect immune repertoires indicates that there are common strategies of host invasion and pathogen eradication. Long-term interactions of bacteria with insects might ensure efficient dissemination of pathogens to other hosts, including humans. PMID:18327270

  3. Insect Keepers

    ERIC Educational Resources Information Center

    Moore, Virginia J.; Chessin, Debby A.; Theobald, Becky

    2010-01-01

    Insects are fascinating creatures--especially when you and your students get up close and personal with them! To that end, the authors facilitated an inquiry-based investigation with an emphasis on identification of the different types of insects found in the school yard, their characteristics, their habitat, and what they eat, while engaging the…

  4. Incredible Insects.

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1989-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. Contents are organized into the following sections: (1) "What Makes an Insect an Insect?," including…

  5. Transplastomic Nicotiana benthamiana plants expressing multiple defence genes encoding protease inhibitors and chitinase display broad-spectrum resistance against insects, pathogens and abiotic stresses.

    PubMed

    Chen, Peng-Jen; Senthilkumar, Rajendran; Jane, Wann-Neng; He, Yong; Tian, Zhihong; Yeh, Kai-Wun

    2014-05-01

    Plastid engineering provides several advantages for the next generation of transgenic technology, including the convenient use of transgene stacking and the generation of high expression levels of foreign proteins. With the goal of generating transplastomic plants with multiresistance against both phytopathogens and insects, a construct containing a monocistronic patterned gene stack was transformed into Nicotiana benthamiana plastids harbouring sweet potato sporamin, taro cystatin and chitinase from Paecilomyces javanicus. Transplastomic lines were screened and characterized by Southern/Northern/Western blot analysis for the confirmation of transgene integration and respective expression level. Immunogold localization analyses confirmed the high level of accumulation proteins that were specifically expressed in leaf and root plastids. Subsequent functional bioassays confirmed that the gene stacks conferred a high level of resistance against both insects and phytopathogens. Specifically, larva of Spodoptera litura and Spodoptera exigua either died or exhibited growth retardation after ingesting transplastomic plant leaves. In addition, the inhibitory effects on both leaf spot diseases caused by Alternaria alternata and soft rot disease caused by Pectobacterium carotovorum subsp. carotovorum were markedly observed. Moreover, tolerance to abiotic stresses such as salt/osmotic stress was highly enhanced. The results confirmed that the simultaneous expression of sporamin, cystatin and chitinase conferred a broad spectrum of resistance. Conversely, the expression of single transgenes was not capable of conferring such resistance. To the best of our knowledge, this is the first study to demonstrate an efficacious stacked combination of plastid-expressed defence genes which resulted in an engineered tolerance to various abiotic and biotic stresses. PMID:24479648

  6. Insects as a Nitrogen Source for Plants

    PubMed Central

    Behie, Scott W.; Bidochka, Michael J.

    2013-01-01

    Many plants have evolved adaptations in order to survive in low nitrogen environments. One of the best-known adaptations is that of plant symbiosis with nitrogen-fixing bacteria; this is the major route by which nitrogen is incorporated into plant biomass. A portion of this plant-associated nitrogen is then lost to insects through herbivory, and insects represent a nitrogen reservoir that is generally overlooked in nitrogen cycles. In this review we show three specialized plant adaptations that allow for the recovery of insect nitrogen; that is, plants gaining nitrogen from insects. First, we show specialized adaptations by carnivorous plants in low nitrogen habitats. Insect carnivorous plants such as pitcher plants and sundews (Nepenthaceae/Sarraceniaceae and Drosera respectively) are able to obtain substantial amounts of nitrogen from the insects that they capture. Secondly, numerous plants form associations with mycorrhizal fungi that can provide soluble nitrogen from the soil, some of which may be insect-derived nitrogen, obtained from decaying insects or insect frass. Finally, a specialized group of endophytic, insect-pathogenic fungi (EIPF) provide host plants with insect-derived nitrogen. These soil-inhabiting fungi form a remarkable symbiosis with certain plant species. They can infect a wide range of insect hosts and also form endophytic associations in which they transfer insect-derived nitrogen to the plant. Root colonizing fungi are found in disparate fungal phylogenetic lineages, indicating possible convergent evolutionary strategies between taxa, evolution potentially driven by access to carbon-containing root exudates. PMID:26462427

  7. Insects as a Nitrogen Source for Plants.

    PubMed

    Behie, Scott W; Bidochka, Michael J

    2013-01-01

    Many plants have evolved adaptations in order to survive in low nitrogen environments. One of the best-known adaptations is that of plant symbiosis with nitrogen-fixing bacteria; this is the major route by which nitrogen is incorporated into plant biomass. A portion of this plant-associated nitrogen is then lost to insects through herbivory, and insects represent a nitrogen reservoir that is generally overlooked in nitrogen cycles. In this review we show three specialized plant adaptations that allow for the recovery of insect nitrogen; that is, plants gaining nitrogen from insects. First, we show specialized adaptations by carnivorous plants in low nitrogen habitats. Insect carnivorous plants such as pitcher plants and sundews (Nepenthaceae/Sarraceniaceae and Drosera respectively) are able to obtain substantial amounts of nitrogen from the insects that they capture. Secondly, numerous plants form associations with mycorrhizal fungi that can provide soluble nitrogen from the soil, some of which may be insect-derived nitrogen, obtained from decaying insects or insect frass. Finally, a specialized group of endophytic, insect-pathogenic fungi (EIPF) provide host plants with insect-derived nitrogen. These soil-inhabiting fungi form a remarkable symbiosis with certain plant species. They can infect a wide range of insect hosts and also form endophytic associations in which they transfer insect-derived nitrogen to the plant. Root colonizing fungi are found in disparate fungal phylogenetic lineages, indicating possible convergent evolutionary strategies between taxa, evolution potentially driven by access to carbon-containing root exudates. PMID:26462427

  8. [Bahaviour of Solenopsis invicta workers to protect pupae from infection by Metarhizium anisopliae].

    PubMed

    Qiu, Hua-Long; Lü, Li-Hua; Zhang, Chun-Yang; He, Yu-Rong

    2014-09-01

    Previous studies have focused on how ants deal with workers infected by pathogens but how pupae are protected from infection by fungi is not well understood. The behavioral mechanisms adopted by Solenopsis invicta (red imported fire ants, RIFA) adult workers to protect pupae against Metarhizium anisopliae infection were studied. We observed the behavioral changes of M. anisopliae infected adult workers in the brood chamber as well as the behavioral changes of healthy workers to fungus exposed pupae. The time of fungus infected workers spent in the pupal chamber reduced significantly from 103.4 s on the first day to 38.5 s on the third day. Moreover, the percentage of time spending on brood care in the pupal chamber reduced significantly from 13.6% on the first day to 3.5% on the third day. When pupae were infected by M. anisopliae, workers performed 5.3 times more grooming to fungus exposed pupae than controls, and the duration of each grooming bout to fungus exposed pupae was 5.2 times longer than controls. Grooming did remove many conidia on the surface of fungus exposed pupae. The mean numbers of conidia on the surface of pupae were 103.1, 51.6 and 31.3 when no workers, two workers and ten workers accompanied a pupa, respectively. The presence of workers resulted in a lower germination rate of conidia on the surface of pupae. The mean germination rates of conidia after 20 h of inoculation on the surface of pupae were 95.1%, 80.4% and 59.9%, in the treatments with no worker, two workers and ten workers respectively. There was a positive correlation between the emergence rate of pupae and the number of accompanying workers. RIFA protect their pupae from infection by M. anisopliae through social be- haviors which enable the sustainable development of their population. PMID:25757319

  9. The effect of leaf biopesticide Mirabilis jalapa and fungi Metarhizium anisopliae to immune response and mortality of Spodoptera exigua instar IV

    NASA Astrophysics Data System (ADS)

    Suryani, A. Irma; Anggraeni, Tjandra

    2014-03-01

    Spodoptera exigua is one of insect causing damage in agriculture sector. This insect can be controlled by a natural biopesticide by combining two agents of biological control, biopesticides Mirabilis jalapa and entomopathogenic fungi Metarhizium anisopliae, considered to be virulent toward a wide range of insects. The objective of research was to determine the effect of biopesticides M. jalapa and fungi M. anisopliae against immune system and mortality of S. exigua. This research used a complete randomized block design with five concentrations Mirabilis jalapa and optimum dose of M. anisopliae. A high dose of M. jalapa (0.8% w/v) is the most effective one to decrease total haemocytes especially granulocyt and plasmatocyt (cellular immune) and decrease the concentration of lectin (humoral immune) from S. exigua (p < 0.05). The combination of M. jalapa (0, 8% w/v) and lethal dose of M. anisopliae 2.59 × 107 spore/ml were significant to increase mortality of S. exigua within 48 hours (p < 0.05).

  10. Anti-viral Responses in Insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although the study of anti-viral responses in insects has lagged behind studies of responses to other types of pathogens, progress has begun to rapidly accelerate over the past few years. Insects are subject to infection by many different kinds of DNA and RNA viruses. These include viruses that ar...

  11. Polydnaviruses: Roles in insect pathology and applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the more unusual groups of insect pathogens consists of members of the family Polydnaviridae, DNA insect viruses that live in mutual symbioses with their associated parasitoid wasp (Hymentoptera) carriers until they are injected into specific Lepidopteran hosts. Once inside this secondary hos...

  12. Meta-analysis of the Effects of Insect Vector Saliva on Host Immune Responses and Infection of Vector-Transmitted Pathogens: A Focus on Leishmaniasis

    PubMed Central

    Ockenfels, Brittany; Michael, Edwin; McDowell, Mary Ann

    2014-01-01

    A meta-analysis of the effects of vector saliva on the immune response and progression of vector-transmitted disease, specifically with regard to pathology, infection level, and host cytokine levels was conducted. Infection in the absence or presence of saliva in naïve mice was compared. In addition, infection in mice pre-exposed to uninfected vector saliva was compared to infection in unexposed mice. To control for differences in vector and pathogen species, mouse strain, and experimental design, a random effects model was used to compare the ratio of the natural log of the experimental to the control means of the studies. Saliva was demonstrated to enhance pathology, infection level, and the production of Th2 cytokines (IL-4 and IL-10) in naïve mice. This effect was observed across vector/pathogen pairings, whether natural or unnatural, and with single salivary proteins used as a proxy for whole saliva. Saliva pre-exposure was determined to result in less severe leishmaniasis pathology when compared with unexposed mice infected either in the presence or absence of sand fly saliva. The results of further analyses were not significant, but demonstrated trends toward protection and IFN-γ elevation for pre-exposed mice. PMID:25275509

  13. Caterpillar-induced plant volatiles remain a reliable signal for foraging wasps during dual attack with a plant pathogen or non-host insect herbivore.

    PubMed

    Ponzio, Camille; Gols, Rieta; Weldegergis, Berhane T; Dicke, Marcel

    2014-08-01

    Plants respond to herbivory with the emission of plant volatiles, which can be used by the herbivores' natural enemies to locate their hosts or prey. In nature, plants are often simultaneously confronted with insect herbivores and phytopathogens, potentially interfering with the attraction of the herbivores' enemies as a result of modifications of the induced volatile blend. Here, we investigated parasitoid (Cotesia glomerata) attraction to volatiles of plants challenged by different attackers, either alone or in combination with Pieris brassicae caterpillars, hosts of C. glomerata. We used a natural system consisting of Brassica nigra plants, eggs and larvae of P. brassicae, Brevicoryne brassicae aphids and the bacterial phytopathogen Xanthomonas campestris pv. campestris. In all cases, parasitoids successfully located host-infested plants, and wasp foraging behaviour was unaffected by the simultaneous presence of a non-host attacker or host eggs. Analysis of the volatile emissions show that the volatile blends of caterpillar-infested treatments were different from those without caterpillars. Furthermore, dually attacked plants could not be separated from those with only caterpillars, regardless of non-host identity, supporting the behavioural data. Our results suggest that, in this system, indirect plant defences may be more resistant to interference than is generally assumed, with volatiles induced during dual attack remaining reliable indicators of host presence for parasitoids. PMID:24697624

  14. Insect maintenance and transmission.

    PubMed

    Kingdom, Heather

    2013-01-01

    Phytoplasmas are plant pathogens of huge economic importance due to responsibility for crop yield losses worldwide. Institutions around the world are trying to understand and control this yield loss at a time when food security is high on government agendas. In order to fully understand the mechanisms of phytoplasma infection and spread, more insect vector and phytoplasma colonies will need to be established for research worldwide. Rearing and study of these colonies is essential in the research and development of phytoplasma control measures. This chapter highlights general materials and methods for raising insect vector colonies and maintenance of phytoplasmas. Specific methods of rearing the maize leafhopper and maize bushy stunt phytoplasma and the aster leafhopper and aster yellows phytoplasma strain witches' broom are also included. PMID:22987405

  15. The InhA2 metalloprotease of Bacillus thuringiensis strain 407 is required for pathogenicity in insects infected via the oral route.

    PubMed

    Fedhila, Sinda; Nel, Patricia; Lereclus, Didier

    2002-06-01

    The entomopathogenic bacterium Bacillus thuringiensis is known to secrete a zinc metalloprotease (InhA) that specifically cleaves antibacterial peptides produced by insect hosts. We identified a second copy of the inhA gene, named inhA2, in B. thuringiensis strain 407 Cry(-). The inhA2 gene encodes a putative polypeptide showing 66.2% overall identity with the InhA protein and harboring the zinc-binding domain (HEXXH), which is characteristic of the zinc-requiring metalloproteases. We used a transcriptional inhA2'-lacZ fusion to show that inhA2 expression is induced at the onset of the stationary phase and is overexpressed in a Spo0A minus background. The presence of a reverse Spo0A box in the promoter region of inhA2 suggests that Spo0A directly regulates the transcription of inhA2. To determine the role of the InhA and InhA2 metalloproteases in pathogenesis, we used allelic exchange to isolate single and double mutant strains for the two genes. Spores and vegetative cells of the mutant strains were as virulent as those of the parental strain in immunized Bombyx mori larvae infected by the intrahemocoelic route. Exponential phase cells of all the strains displayed the same in vitro potential for colonizing the vaccinated hemocoel. We investigated the synergistic effect of the mutant strain spores on the toxicity of Cry1C proteins against Galleria mellonella larvae infected via the oral pathway. The spores of DeltainhA2 mutant strain were ineffective in providing synergism whereas those of the DeltainhA mutant strain were not. These results indicate that the B. thuringiensis InhA2 zinc metalloprotease has a vital role in virulence when the host is infected via the oral route. PMID:12029046

  16. WetA and VosA are distinct regulators of conidiation capacity, conidial quality, and biological control potential of a fungal insect pathogen.

    PubMed

    Li, Fang; Shi, Han-Qiang; Ying, Sheng-Hua; Feng, Ming-Guang

    2015-12-01

    Many filamentous fungi produce only conidia for dispersal and survival in vitro or in vivo. Here, we show that the developmental regulator WetA and the velvet protein VosA are not only required for conidial maturation but indispensable for conidiation in Beauveria bassiana, a filamentous entomopathogen. Deletion of wetA or vosA resulted in more than 90 % transcriptional depression of brlA and abaA, two activator genes in the central developmental pathway, during the critical period of conidiophore development and conidiation. Consequently, ΔwetA and ΔvosA strains lost 98 % in and 88 % of their conidiation capacities under optimal culture conditions, respectively. The conidia of ΔwetA showed more defective features than those of ΔvosA, including smaller size, lesser density, lower hydrophobicity, and impaired cell walls although intracellular trehalose content decreased more in the aging culture of ΔvosA than of ΔwetA. As a result, conidial sensitivity to cell wall perturbation was elevated in ΔwetA but unaffected in ΔvosA, which produced conidia more sensitive to the oxidant menadione and the wet-heat stress at 45 °C. Both deletion mutants showed similar defects in conidial tolerance to high osmolarity or UV-B irradiation but no change in conidial sensitivity to the other oxidant H2O2 or the fungicide carbendazim. Moreover, ΔwetA lost more virulence to Galleria mellonella larvae than ΔvosA. All these phenotypical changes were restored by either wetA or vosA complementation. Taken together, WetA and VosA are indispensable for asexual development and contribute differentially to conidial quality and hence the biological control potential of B. bassiana against insect pests. PMID:26243054

  17. Insect Phylogenomics

    PubMed Central

    Behura, Susanta K.

    2015-01-01

    With the advent of next-generation sequencing methods, phylogenetics has taken a new turn in the recent years. Phylogenomics, the integration of phylogenetics with genome data, has emerged as a powerful approach to study systematics and evolution of species. Recently, breakthrough researches employing phylogenomic tools have provided better insights into the timing and pattern of insect evolution. The next-generation sequencing methods are now increasingly used by entomologists to generate genomic and transcript sequences of various insect species and strains. These data provide opportunities for comparative genomics and large-scale multigene phylogenies of diverse lineages of insects. Phylogenomic investigations help us better understand systematic and evolutionary relationships of insect species that play important roles as herbivores, predators, detritivores, pollinators, or disease vectors. It is important that we critically assess the prospects and limitations of phylogenomic methods. In this review, I describe the current status, outline the major challenges, and remark on potential future applications of phylogenomic tools in studying insect systematics and evolution. PMID:25963452

  18. A high-throughput gene disruption methodology for the entomopathogenic fungus Metarhizium robertsii.

    PubMed

    Xu, Chuan; Zhang, Xing; Qian, Ying; Chen, Xiaoxuan; Liu, Ran; Zeng, Guohong; Zhao, Hong; Fang, Weiguo

    2014-01-01

    Systematic gene disruption is a direct way to interrogate a fungal genome to functionally characterize the full suite of genes involved in various biological processes. Metarhizium robertsii is extraordinarily versatile, and it is a pathogen of arthropods, a saprophyte and a beneficial colonizer of rhizospheres. Thus, M. robertsii can be used as a representative to simultaneously study several major lifestyles that are not shared by the "model" fungi Saccharomyces cerevisiae and Neurospora crassa; a systematic genetic analysis of M. robertsii will benefit studies in other fungi. In order to systematically disrupt genes in M. robertsii, we developed a high-throughput gene disruption methodology, which includes two technologies. One is the modified OSCAR-based, high-throughput construction of gene disruption plasmids. This technology involves two donor plasmids (pA-Bar-OSCAR with the herbicide resistance genes Bar and pA-Sur-OSCAR with another herbicide resistance gene Sur) and a recipient binary plasmid pPK2-OSCAR-GFP that was produced by replacing the Bar cassette in pPK2-bar-GFP with a ccdB cassette and recombination recognition sites. Using this technology, a gene disruption plasmid can be constructed in one cloning step in two days. The other is a highly efficient gene disruption technology based on homologous recombination using a Ku70 deletion mutant (ΔMrKu70) as the recipient strain. The deletion of MrKu70, a gene encoding a key component involved in nonhomologous end-joining DNA repair in fungi, dramatically increases the gene disruption efficiency. The frequency of disrupting the conidiation-associated gene Cag8 in ΔMrKu70 was 93% compared to 7% in the wild-type strain. Since ΔMrKu70 is not different from the wild-type strain in development, pathogenicity and tolerance to various abiotic stresses, it can be used as a recipient strain for a systematic gene disruption project to characterize the whole suite of genes involved in the biological processes of

  19. A High-Throughput Gene Disruption Methodology for the Entomopathogenic Fungus Metarhizium robertsii

    PubMed Central

    Xu, Chuan; Zhang, Xing; Qian, Ying; Chen, Xiaoxuan; Liu, Ran; Zeng, Guohong; Zhao, Hong; Fang, Weiguo

    2014-01-01

    Systematic gene disruption is a direct way to interrogate a fungal genome to functionally characterize the full suite of genes involved in various biological processes. Metarhizium robertsii is extraordinarily versatile, and it is a pathogen of arthropods, a saprophyte and a beneficial colonizer of rhizospheres. Thus, M. robertsii can be used as a representative to simultaneously study several major lifestyles that are not shared by the “model” fungi Saccharomyces cerevisiae and Neurospora crassa; a systematic genetic analysis of M. robertsii will benefit studies in other fungi. In order to systematically disrupt genes in M. robertsii, we developed a high-throughput gene disruption methodology, which includes two technologies. One is the modified OSCAR-based, high-throughput construction of gene disruption plasmids. This technology involves two donor plasmids (pA-Bar-OSCAR with the herbicide resistance genes Bar and pA-Sur-OSCAR with another herbicide resistance gene Sur) and a recipient binary plasmid pPK2-OSCAR-GFP that was produced by replacing the Bar cassette in pPK2-bar-GFP with a ccdB cassette and recombination recognition sites. Using this technology, a gene disruption plasmid can be constructed in one cloning step in two days. The other is a highly efficient gene disruption technology based on homologous recombination using a Ku70 deletion mutant (ΔMrKu70) as the recipient strain. The deletion of MrKu70, a gene encoding a key component involved in nonhomologous end-joining DNA repair in fungi, dramatically increases the gene disruption efficiency. The frequency of disrupting the conidiation-associated gene Cag8 in ΔMrKu70 was 93% compared to 7% in the wild-type strain. Since ΔMrKu70 is not different from the wild-type strain in development, pathogenicity and tolerance to various abiotic stresses, it can be used as a recipient strain for a systematic gene disruption project to characterize the whole suite of genes involved in the biological processes

  20. Allergic responses to the biopesticide Metarhizium anisopliae in Balb/c mice.

    PubMed

    Ward, M D; Sailstad, D M; Selgrade, M K

    1998-10-01

    Metarhizium anisopliae is used as a microbial pesticide to control cockroaches and other insects. M. anisopliae has demonstrated neither infectivity nor toxicity in mammals. However, allergenicity has not been assessed. M. anisopliae is a prototype for other organisms released into the environment for pesticide or other beneficial applications. Hence this study is part of an effort to develop methods for screening such organisms for allergenic potential. Soluble factors from fungal components were combined in equal protein amounts to form a crude fungal antigen (MACA). Balb/c mice were intratracheally (IT) challenged with 25 micrograms fungal antigen 13 days post intraperitoneal sensitization with the fungal antigen in alhydrogel adjuvant. Additionally, mice were sensitized with adjuvant alone or chitin media in adjuvant as experimental controls. Serum and bronchoalveolar lavage fluid (BALF) were harvested prior to challenge and at 1 and 7 days post IT challenge (DPIT). These mice exhibited immune and pulmonary inflammatory responses to MACA characteristic of allergy. Total serum IgE for antigen-sensitized animals increased 7.6- and 14.7-fold over that for chitin media and adjuvant controls, respectively, at 7 DPIT. Less striking increases were seen at 24 DPIT and prior to challenge. BALF IL-4 was dramatically elevated only in MACA-sensitized and challenged mice and only at 1 DPIT. Additionally, there was a dose-dependent increase in BALF eosinophils from MACA-sensitized mice at both 1 and 7 DPIT. While lymphocyte counts were increased for all treatment groups at 1 DPIT, by 7 DPIT lymphocyte counts for MACA-sensitized mice only were significantly elevated compared to controls. Pulmonary inflammation, edema, and cell damage were apparent at 1 DPIT (25 micrograms MACA), as indicated by a neutrophilic influx and elevated levels of total protein and LDH, in both sensitized and control groups. These effects were significantly decreased, but not eliminated by reduction

  1. Susceptibility of Agrilus planipennis (Coleoptera: Buprestidae) to Beauveria bassiana and Metarhizium anisopliae.

    PubMed

    Liu, Houping; Bauer, Leah S

    2006-08-01

    The susceptibility of Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) to selected strains of the entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin was evaluated through bioassays with direct immersion or foliar exposure under laboratory conditions. Results showed that A. planipennis adults were susceptible to B. bassiana and M. anisoplae. Significant time-mortality response was found for each isolates. Isolate B. bassiana GHA killed A. planipennis adults at a faster rate compared with other isolates tested, with the lowest average time-to-death values. The LC50 values estimated under direct immersion method ranged from 1.7 x 10(5) to 1.9 x 10(7), 3.5 x 10(4) to 5.3 x 10(5), and 4.1 x 10(3) to 2.9 x 10(5) conidia/ml for B. basissiana and from 3.2 x 10(6) to 1.1 x 10(7), 4.5 x 10(3) to 4.5 x 10(5), and 1.4 x 10(2) to 1.2 x 10(5) conidia/ml for M. anisopliae at 4, 5, and 6 d after treatment, respectively. By days 5 and 6, B. bassiana GHA outperformed all other isolates tested except ARSEF 7234, followed by ARSEF 7152, 6393, and 7180. Significant concentration-mortality response was also observed for two B. bassiana GHA formulations, BotaniGard ES and Mycotrol O, and M. anisopliae F52 when insects were treated through foliar exposure. The LC50 values ranged from 114.5 to 309.6, 18.4 to 797.3, and 345.3 to 362.0 conidia/cm2 for BotaniGard, Mycotrol, and M. anisopliae F52, respectively. Based on the results of these bioassays, the efficacy of both B. bassiana GHA formulations and M. anisopliae F52 were similar against adult A. planipennis. The potential use of entomopathogenic fungi for management of A. planipennis in North America is discussed. PMID:16937660

  2. Microbiome influences on insect host vector competence

    PubMed Central

    Weiss, Brian

    2011-01-01

    Insect symbioses lack the complexity and diversity of those associated with higher eukaryotic hosts. Symbiotic microbiomes are beneficial to their insect hosts in many ways, including dietary supplementation, tolerance to environmental perturbations and maintenance and/or enhancement of host immune system homeostasis. Recent studies have also highlighted the importance of the microbiome in the context of host pathogen transmission processes. Here we provide an overview of the relationship between insect disease vectors, such as tsetse flies and mosquitoes, and their associated microbiome. Several mechanisms are discussed through which symbiotic microbes may influence their host’s ability to transmit pathogens, as well as potential disease control strategies that harness symbiotic microbes to reduce pathogen transmission through an insect vector. PMID:21697014

  3. Comparative impact of artificial selection for fungicide resistance on Beauveria bassiana and Metarhizium brunncum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hypocreales fungi such as Beauveria bassiana and Metarhizium anisopliae can be negatively affected by fungicides thereby reducing their biocontrol potential. The overall goal of this study was to investigate the impact of artificial selection for fungicide resistance on two commercial entomopathoge...

  4. THE IDENTIFICATION AND CHARACTERIZATION OF AN IGE-INDUCING PROTEIN IN METARHIZIUM ANISOPLIAE EXTRACT

    EPA Science Inventory

    The Identification and Characterization of an IgE-Inducing Protein in Metarhizium anisopliae Extract

    Marsha D.W. Ward1, Lisa B. Copeland1, Maura J. Donahue2, and Jody A. Shoemaker3
    1ORD, NHEERL, US EPA, RTP, NC; 2Oak Ridge Institute for Science and Education, Cincinnati...

  5. Ovicidal activity of Metarhizium brunneum (Mb F52) on dengue fever vector, Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ovicidal activity of Metarhizium brunneum F52 (Mb F52) grown from granules was evaluated against Aedes aegypti eggs over time. Survival of larvae from treated eggs was significantly less when compared with untreated eggs at 7, 10 and 14 days post treatment. Only 27 % of treated eggs produced vi...

  6. Promise versus performance: Working toward the use of Metarhizium anisopliae as a biological control for wireworms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A Canadian isolate of Metarhizium anisopliae has shown promise as a biological control for wireworms based on repeated success in laboratory and greenhouse studies but field efficacy has been inconsistent. Laboratory experiments designed to explain these mixed results have pointed to certain biotic...

  7. Metacridamides A and B, bioactive macrocycles from conidia of the entomopathogenic fungus Metarhizium acridum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metarhizium acridum, an entomopathogenic fungus, has been commercialized and used successfully for biocontrol of grasshopper pests in Africa and Australia. Its conidia produce two novel 17-membered macrocycles, metacridamides A (1) and B (2), which consist of a Phe unit condensed with a nonaketide....

  8. Production of microsclerotia by brazilian strains of metarhizium spp. using submerged liquid culture fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated the potential production and desiccation tolerance of microsclerotia (MS) by Brazilian strains of Metarhizium. anisopliae [Ma], M. acridum [Mc] and M. robertsii [Mr]. These fungi were grown in a liquid medium containing 16 g carbon l-1 with a carbon:nitrogen ratio of 50:1. One hundre...

  9. Reduction in fitness of female Asian longhorned beetle (Anoplophora glabripennis) infected with Metarhizium anisopliae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioassays were conducted to document the effects of Metarhizium anisopliae infection of adult female Anoplophora glabripennis on reproduction before female death and subsequent survival of offspring. The effect of infection on fecundity was evaluated for both newly eclosed females and females alread...

  10. Metachelins, mannosylated and N-oxidized coprogen-type siderophores from Metarhizium robertsii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Under iron-depleted culture conditions, the entomopathogenic fungus Metarhizium robertsii (Bischoff, Humber, and Rehner) (= M. anisopliae) produces a complex of extracellular siderophores including novel O-glycosylated and/or N-oxidized coprogen-type compounds as well as the known fungal siderophore...

  11. Challenges in Using Metarhizium anisopliae for Biocontrol of Sugarbeet Root Maggot, Tetanops myopaeformis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metarhizium anisopliae is under development as a microbial pest control agent of the Ulidiid fly, Tetanops myopaeformis (Sugarbeet Root Maggot), the most serious sugar beet pest in the United States. The fungus can be deployed by several means to create a “minefield” of infectious spores in the habi...

  12. Metarhizium anisopliae for controlling Rhipicephalus microplus ticks under field conditions.

    PubMed

    Camargo, Mariana G; Nogueira, Michel R S; Marciano, Allan F; Perinotto, Wendell M S; Coutinho-Rodrigues, Caio J B; Scott, Fábio B; Angelo, Isabele C; Prata, Márcia C A; Bittencourt, Vânia R E P

    2016-06-15

    Metarril SP Organic is a product based on the fungus Metarhizium anisopliae, which was developed for controlling agricultural pests. The present study evaluated the effect of Metarril SP Organic plus 10% mineral oil, for controlling Rhipicephalus microplus under field conditions. Three groups were formed: Control group, which received no treatment; Oil control group, which was bathed only with water, Tween 80 and mineral oil; and Metarril group, bathed in the oil-based formulation Metarril SP Organic. Two treatments per group were performed and to verify the effect of the treatments, all R. microplus ticks between 4.5 and 8.0mm in length on the left side of the cattle were counted on days +7, +14 and +21 after each treatment, and a sample of engorged females was collected for evaluation of biological parameters. The Metarril SP Organic oil formulation showed efficacy ranging from 8.53 to 90.53%. The average efficacy of the oil-based formulation of Metarril SP Organic was 75.09 and 46.59% compared with the groups Control and Oil control, respectively. There were no significant changes in biological parameters of engorged R. microplus females collected from animals. Although there was no significant difference in the amount of ticks between the Oil control and Metarril groups, it is believed that the association of mineral oil with Metarril SP Organic product is effective in R. microplus tick control in field. Thus, this association has potential to be used in strategic control programs of cattle tick. PMID:27198775

  13. Ecological Considerations in Producing and Formulating Fungal Entomopathogens for Use in Insect Biocontrol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect pests persist in a wide-variety of agricultural, arboreal, and urban environments. Effective control with fungal entomopathogens using inundation biocontrol requires an understanding of the ecology of the target insect, fungal pathogen, and the insect-pathogen interaction. Historically, the d...

  14. Ecological Considerations in Producing and Formulating Fungal Entomopathogens for Use in Insect Biocontrol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect pests persist in a wide variety of agricultural, arboreal, and urban environments. Effective control with fungal entomopathogens using inundation biocontrol requires an understanding of the ecology of the target insect, fungal pathogen, and the insect-pathogen interaction. Historically, the...

  15. Fitness costs to Helicoverpa armigera after exposure to sub-lethal concentrations of Metarhizium anisopliae sensu lato: Study on F1 generation.

    PubMed

    Jarrahi, Azadeh; Safavi, Seyed Ali

    2016-07-01

    The entomopathogenic fungus, Metarhizium anisopliae (Metsch.) Sorokin is a valuable biocontrol agent attacking larval stages of many lepidopteran pests including Helicoverpa armigera (Hübner). Sub-lethal effects of M. anisopliae sensu lato (s.l.) (isolate M14) were investigated on life table parameters of offspring from treated larvae of H. armigera. Duration of different life stages was significantly affected by fungal treatments. Fecundity was decreased in females derived from H. armigera larvae treated with M. anisopliae s.l. Sub-lethal concentrations of the entomopathogen reduced the net reproduction rate (R0) of F1 insects for all treatments compared with the control. Similar reductions were observed for the intrinsic and the finite rates of increase (rm and λ, respectively). The mean generation time (T) and the doubling time (DT) were statistically higher in offspring of individuals exposed to some fungal concentrations than control insects. Our results indicated that there was a significant decrease in the F1 population of H. armigera derived from larvae that were exposed to sub-lethal concentrations of M. anisopliae s.l. PMID:27247225

  16. Enzyme activities associated with oxidative stress in Metarhizium anisopliae during germination, mycelial growth, and conidiation and in response to near-UV irradiation.

    PubMed

    Miller, Charles D; Rangel, Drauzio; Braga, Gilberto U L; Flint, Stephan; Kwon, Sun-Il; Messias, Claudio L; Roberts, Donald W; Anderson, Anne J

    2004-01-01

    Metarhizium anisopliae isolates have a wide insect host range, but an impediment to their commercial use as a biocontrol agent of above-ground insects is the high susceptibility of spores to the near-UV present in solar irradiation. To understand stress responses in M. anisopliae, we initiated studies of enzymes that protect against oxidative stress in two strains selected because their spores differed in sensitivity to UV-B. Spores of the more near-UV resistant strain in M. anisopliae 324 displayed different isozyme profiles for catalase-peroxidase, glutathione reductase, and superoxide dismutase when compared with the less resistant strain 2575. A transient loss in activity of catalase-peroxidase and glutathione reductase was observed during germination of the spores, whereas the intensity of isozymes displaying superoxide dismutase did not change as the mycelium developed. Isozyme composition for catalase-peroxidases and glutathione reductase in germlings changed with growth phase. UV-B exposure from lamps reduced the activity of isozymes displaying catalase-peroxidase and glutathione reductase activities in 2575 more than in 324. The major effect of solar UV-A plus UV-B also was a reduction in catalase-peroxidases isozyme level, a finding confirmed by measurement of catalase specific activity. Impaired growth of M. anisopliae after near-UV exposure may be related to reduced abilities to handle oxidative stress. PMID:15052320

  17. Effect of Metarhizium anisopliae on the Fertility and Fecundity of Two Species of Fruit Flies and Horizontal Transmission of Mycotic Infection

    PubMed Central

    Sookar, P.; Bhagwant, S.; Allymamod, M.N.

    2014-01-01

    In Mauritius, the peach fruit fly, Bactrocera zonata Saunders (Diptera: Tephritidae), and the melon fly, Bactrocera cucurbitae (Coquillett), are the major pest of fruits and vegetables, respectively. Fruit growers make use of broad-spectrum insecticides to protect their crops from fruit fly attack. This method of fruit fly control is hazardous to the environment and is a threat to beneficial insects. The entomopathogenic fungus, Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae), which was isolated from the soils of Mauritius, was used to investigate whether fungus-treated adult fruit flies could transfer conidia to non-treated flies during mating, and whether fungal infection could have an effect on mating behavior, fecundity, and fertility of the two female fruit fly species. When treated male flies were maintained together with non-treated female flies, they were able to transmit infection to untreated females, resulting in high mortalities. Similarly, fungus-infected female flies mixed with untreated males also transmitted infections to males, also resulting in high mortalities. Infection by M. anisopliae also resulted in the reduction of the number of eggs produced by females of B. cucurbitae. The results suggest that M. anisopliae may have potential for use in integrated control programs of B. zonata and B. cucurbitae using the sterile insect technique in Mauritius. PMID:25201230

  18. Insects: A nutritional alternative

    NASA Technical Reports Server (NTRS)

    Dufour, P. A.

    1981-01-01

    Insects are considered as potential food sources in space. Types of insects consumed are discussed. Hazards of insect ingestion are considered. Insect reproduction, requirements, and raw materials conversion are discussed. Nutrition properties and composition of insects are considered. Preparation of insects as human food is discussed.

  19. Microsclerotia of Metarhizium brunneum F52 applied in hydromulch for control of Asian longhorned beetles (Coleoptera: Cerambycidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The entomopathogenic fungus Metarhizium brunneum (Petch), strain F52 (Hypocreales: Clavicipitaceae) is able to produce environmentally persistent microsclerotia. Incorporating these desiccation-tolerant M. brunneum F52 microsclerotia (Mb MS) granules into hydromulch [a mixture of water + wheat straw...

  20. Evaluating different carriers of Metarhizium brunneum F52 microsclerotia for control of adult Asian longhorned beetles (Coleoptera: Cerambycidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microsclerotia (MS) of Metarhizium brunneum strain F52 (Hypocreales: Clavicipitaceae), were processed as granules using three carriers: kaolin clay, microcrystalline cellulose (MCC) or diatomaceous earth (DE). In a series of experiments aimed at comparing viable conidial production and subsequent pe...

  1. Evaluating different granule carriers of Metarhizium brunneum F52 microsclerotia for control of adult Asian longhorned beetles (Coleoptera: Cerambycidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microsclerotia (MS) of Metarhizium brunneum strain F52 (Hypocreales: Clavicipitaceae), were processed as granules using three carriers: kaolin clay, microcrystalline cellulose (MCC) or diatomaceous earth (DE). In a series of experiments aimed at comparing viable conidial production and subsequent pe...

  2. Insect evolution.

    PubMed

    Engel, Michael S

    2015-10-01

    It goes without saying that insects epitomize diversity, and with over a million documented species they stand out as one of the most remarkable lineages in the 3.5-billion-year history of life on earth (Figure 1). This reality is passé to even the layperson and is taken for granted in the same way none of us think much of our breathing as we go about our day, and yet insects are just as vital to our existence. Insects are simultaneously familiar and foreign to us, and while a small fraction are beloved or reviled, most are simply ignored. These inexorable evolutionary overachievers outnumber us all, their segmented body plan is remarkably labile, they combine a capacity for high rates of speciation with low levels of natural extinction, and their history of successes eclipses those of the more familiar ages of dinosaurs and mammals alike. It is their evolution - persisting over vast expanses of geological time and inextricably implicated in the diversification of other lineages - that stands as one of the most expansive subjects in biology. PMID:26439349

  3. Microsclerotia of Metarhizium brunneum F52 Applied in Hydromulch for Control of Asian Longhorned Beetles (Coleoptera: Cerambycidae).

    PubMed

    Goble, Tarryn A; Hajek, Ann E; Jackson, Mark A; Gardescu, Sana

    2015-04-01

    The entomopathogenic fungus Metarhizium brunneum (Petch) strain F52 (Hypocreales: Clavicipitaceae) is able to produce environmentally persistent microsclerotia (hyphal aggregates). Microsclerotia of strain F52 produced as granules and incorporated into hydromulch (hydro-seeding straw, water, and a natural glue) provides a novel mycoinsecticide that could be sprayed onto urban, forest, or orchard trees. We tested this formulation against adult Asian longhorned beetles (Anoplophora glabripennis (Motschulsky)) using three substrates (moistened bark, dry bark, absorbent bench liner) sprayed with a low rate (9 microsclerotia granules/cm2) of hydromulch. Median survival times of beetles continuously exposed to sprayed moist bark or absorbent liner were 17.5 and 19.5 d, respectively. Beetles exposed to sprayed dry bark, which had a lower measured water activity, lived significantly longer. When moist bark pieces were sprayed with increased rates of microsclerotia granules in hydromulch, 50% died by 12.5 d at the highest application rate, significantly sooner than beetles exposed to lower application rates (16.5-17.5 d). To measure fecundity effects, hydromulch with or without microsclerotia was sprayed onto small logs and pairs of beetles were exposed for a 2-wk oviposition period in containers with 98 or 66% relative humidity. At 98% humidity, oviposition in the logs was highest for controls (18.3±1.4 viable offspring per female) versus 3.9±0.8 for beetles exposed to microsclerotia. At 66% humidity, fecundities of controls and beetles exposed to microsclerotia were not significantly different. This article presents the first evaluation of M. brunneum microsclerotia in hydromulch applied for control of an arboreal insect pest. PMID:26470154

  4. Insect abatement system

    NASA Technical Reports Server (NTRS)

    Spiro, Clifford Lawrence (Inventor); Burnell, Timothy Brydon (Inventor); Wengrovius, Jeffrey Hayward (Inventor)

    1997-01-01

    An insect abatement system prevents adhesion of insect debris to surfaces which must be kept substantially free of insect debris. An article is coated with an insect abatement coating comprising polyorganosiloxane with a Shore A hardness of less than 50 and a tensile strength of less than 4 MPa. A method for preventing the adhesion of insect debris to surfaces includes the step of applying an insect abatement coating to a surface which must be kept substantially free of insect debris.

  5. Intracellular siderophore but not extracellular siderophore is required for full virulence in Metarhizium robertsii.

    PubMed

    Giuliano Garisto Donzelli, Bruno; Gibson, Donna M; Krasnoff, Stuart B

    2015-09-01

    Efficient iron acquisition mechanisms are fundamental for microbial survival in the environment and for pathogen virulence within their hosts. M. robertsii produces two known iron-binding natural products: metachelins, which are used to scavenge extracellular iron, and ferricrocin, which is strictly intracellular. To study the contribution of siderophore-mediated iron uptake and storage to M. robertsii fitness, we generated null mutants for each siderophore synthase gene (mrsidD and mrsidC, respectively), as well as for the iron uptake transcriptional repressor mrsreA. All of these mutants showed impaired germination speed, differential sensitivity to hydrogen peroxide, and differential ability to overcome iron chelation on growth-limiting iron concentrations. RT-qPCR data supported regulation of mrsreA, mrsidC, and mrsidD by supplied iron in vitro and during growth within the insect host, Spodoptera exigua. We also observed strong upregulation of the insect iron-binding proteins, transferrins, during infection. Insect bioassays revealed that ferricrocin is required for full virulence against S. exigua; neither the loss of metachelin production nor the deletion of the transcription factor mrsreA significantly affected M. robertsii virulence. PMID:26135511

  6. Metabolomics reveals insect metabolic responses associated with fungal infection.

    PubMed

    Xu, Yong-Jiang; Luo, Feifei; Gao, Qiang; Shang, Yanfang; Wang, Chengshu

    2015-06-01

    The interactions between insects and pathogenic fungi are complex. We employed metabolomic techniques to profile insect metabolic dynamics upon infection by the pathogenic fungus Beauveria bassiana. Silkworm larvae were infected with fungal spores and microscopic observations demonstrated that the exhaustion of insect hemocytes was coupled with fungal propagation in the insect body cavity. Metabolomic analyses revealed that fungal infection could significantly alter insect energy and nutrient metabolisms as well as the immune defense responses, including the upregulation of carbohydrates, amino acids, fatty acids, and lipids, but the downregulation of eicosanoids and amines. The insect antifeedant effect of the fungal infection was evident with the reduced level of maclurin (a component of mulberry leaves) in infected insects but elevated accumulations in control insects. Insecticidal and cytotoxic mycotoxins like oosporein and beauveriolides were also detected in insects at the later stages of infection. Taken together, the metabolomics data suggest that insect immune responses are energy-cost reactions and the strategies of nutrient deprivation, inhibition of host immune responses, and toxin production would be jointly employed by the fungus to kill insects. The data obtained in this study will facilitate future functional studies of genes and pathways associated with insect-fungus interactions. PMID:25895944

  7. Symbiont-mediated functions in insect hosts

    PubMed Central

    Su, Qi; Zhou, Xiaomao; Zhang, Youjun

    2013-01-01

    The bacterial endosymbionts occur in a diverse array of insect species and are usually rely within the vertical transmission from mothers to offspring. In addition to primary symbionts, plant sap-sucking insects may also harbor several diverse secondary symbionts. Bacterial symbionts play a prominent role in insect nutritional ecology by aiding in digestion of food or supplementing nutrients that insect hosts can’t obtain sufficient amounts from a restricted diet of plant phloem. Currently, several other ecologically relevant traits mediated by endosymbionts are being investigated, including defense toward pathogens and parasites, adaption to environment, influences on insect-plant interactions, and impact of population dynamics. Here, we review recent theoretical predictions and experimental observations of these traits mediated by endosymbionts and suggest that clarifying the roles of symbiotic microbes may be important to offer insights for ameliorating pest invasiveness or impact. PMID:23710278

  8. Effect of fermentation media on the production, efficacy, and storage stability of Metarhizium brunneum microsclerotia formulated as a prototype granule.

    PubMed

    Behle, Robert W; Jackson, Mark A

    2014-04-01

    New liquid fermentation techniques for the production of the bioinsecticidal fungus Metarhizium brunneum strain F-52 have resulted in the formation of microsclerotia (MS), a compact, melonized-hyphal structure capable of surviving desiccation and formulation as dry granules. When rehydrated, these MS granules germinate to produce conidia that can infect susceptible insects. Fermentation media containing cottonseed or soy flours as nitrogen sources and formulated at two carbon to nitrogen ratios (C:N), 30:1 or 50:1, were evaluated forproduction of microsclerotia. Dry MS granule samples were compared for storage stability based on conidia production, and insecticidal activity against larvae of the lesser mealworm, Alphitobius diaperinus (Panzer), using a potting soil bioassay. Cottonseed and soy flours were equivalent for production, MS granule viability, and insecticidal activity. Fermentation media containing higher nitrogen concentrations (30:1 C:N) resulted in greater biomass accumulation and greater production of conidia from granules regardless of the nitrogen source. MS granules made with M. brunneum cultures grown in media with 30:1 C:N produced 8.5 x 10(9) conidia per gram of granules after 8-d incubation, significantly higher than MS granules made using fungus produced using 50:1 C:N media (5.5 x 10(9) conidia per gram dry MS granules). The LC50 for larval mortality was 8.05 x 10(5) conidia per cup, equivalent to applications of 94 or 147 microg granules per cup for granules made from high and low nitrogen media, respectively. Measurements of water activity were not significantly different among granule samples (0.28-0.29) even though granules made from high nitrogen media had higher moisture content (> 5.2%) compared with granules made from low nitrogen media (< 4.6%). Higher initial conidial production was reflected in longer storage stability at 25 degrees C, with half-lives estimated at 3.7 and 1.7 wk for 30:1 and 50:1 C:N ratios, respectively. These

  9. Discovering the secondary metabolite potential encoded within Entomopathogenic Fungi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article discusses the secondary metabolite potential of the insect pathogens Metarhizium and Beauveria, including a bioinformatics analysis of secondary metabolite genes for which no products are yet identified....

  10. Allergies to Insect Venom

    MedlinePlus

    ... The smell of food attracts these insects.  Use insect repellents and keep insecticide available. Treatment tips:  Venom immunotherapy (allergy shots to insect venom(s) is highly effective in preventing subsequent sting ...

  11. A natural fungal infection of a sylvatic cockroach with Metarhizium blattodeae sp. nov., a member of the M. flavoviride species complex

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wild, forest-dwelling cockroach from the subfamily Ectobiidae (order Blattodea) in a nature reserve in Cavalcante, in the state of Goias, Brazil, was found to be infected by a new, genetically distinct species in the Metarhizium flavoviride species complex that we describe here as Metarhizium blat...

  12. Insect transgenesis and the sterile insect technique

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The establishment of broadly applicable insect transgenesis systems will enable the analyses of gene function in diverse insect species. This will greatly increase our understanding of diverse aspects of biology so far not functionally addressable. Moreover, insect transgenesis will provide novel st...

  13. What Makes an Insect an Insect?

    ERIC Educational Resources Information Center

    NatureScope, 1985

    1985-01-01

    Provides background information on characteristics common to all insects, activities, and student materials (ready-to-copy games, puzzles, coloring pages, worksheets, and/or mazes) which describe: how insects are classified; how they are different from other animals; and the main insect characteristics. Activities include recommended age levels,…

  14. Potential of two entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae (Coleoptera: Scarabaeidae), as biological control agents against the June beetle.

    PubMed

    Erler, Fedai; Ates, A Ozgur

    2015-01-01

    The aim of this study was to evaluate the effectiveness of the entomopathogenic fungi (EPF), Beauveria bassiana (Bals.) Vuill. (Deuteromycotina: Hyphomycetes) strain PPRI 5339 [BroadBand, an emulsifiable spore concentrate (EC) formulation] and Metarhizium anisopliae (Metsch.) Sorokin (Hypocreales: Clavicipitaceae) strain F52 [Met52, both EC and granular (GR) formulations] against the larvae of Polyphylla fullo (L.) (Coleoptera: Scarabaeidae). Larvicidal bioassays were performed in foam boxes (100 by 75 by 50 cm; length by width by height), containing moist soil medium with some humus and potato tubers as food. Although the B. bassiana product (min. 4 × 10(9) conidia/ml) was applied at 100, 150, and 200 ml/100 l water; M. anisopliae strain F52 was applied at 500, 1,000, and 1,500 g/m(3) of moist soil medium for GR (9 × 10(8) cfu/g) and 75, 100, and 125 ml/100 l water for EC (5.5 × 10(9) conidia/ml) formulation. Both fungi were pathogenic to larvae of the pest; however, young larvae (1st and 2nd instars) were more susceptible to infection than older ones (3rd instar). Mortality rates of young and older larvae varied with conidial concentration of both fungi and elapsed time after application. The B. bassiana product was more effective than both of the formulations of the M. anisopliae product, causing mortalities up to 79.8 and 71.6% in young and older larvae, respectively. The highest mortality rates of young and older larvae caused by the M. anisopliae product were 74.1 and 67.6% for the GR formulation, 70.2 and 61.8% for the EC formulation, respectively. These results may suggest that both fungi have potential to be used for management of P. fullo. PMID:25881632

  15. Potential of two entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae (Coleoptera: Scarabaeidae), as biological control agents against the June beetle

    PubMed Central

    Erler, Fedai; Ates, A. Ozgur

    2015-01-01

    The aim of this study was to evaluate the effectiveness of the entomopathogenic fungi (EPF), Beauveria bassiana (Bals.) Vuill. (Deuteromycotina: Hyphomycetes) strain PPRI 5339 [BroadBand, an emulsifiable spore concentrate (EC) formulation] and Metarhizium anisopliae (Metsch.) Sorokin (Hypocreales: Clavicipitaceae) strain F52 [Met52, both EC and granular (GR) formulations] against the larvae of Polyphylla fullo (L.) (Coleoptera: Scarabaeidae). Larvicidal bioassays were performed in foam boxes (100 by 75 by 50 cm; length by width by height), containing moist soil medium with some humus and potato tubers as food. Although the B. bassiana product (min. 4 × 109 conidia/ml) was applied at 100, 150, and 200 ml/100 l water; M. anisopliae strain F52 was applied at 500, 1,000, and 1,500 g/m3 of moist soil medium for GR (9 × 108 cfu/g) and 75, 100, and 125 ml/100 l water for EC (5.5 × 109 conidia/ml) formulation. Both fungi were pathogenic to larvae of the pest; however, young larvae (1st and 2nd instars) were more susceptible to infection than older ones (3rd instar). Mortality rates of young and older larvae varied with conidial concentration of both fungi and elapsed time after application. The B. bassiana product was more effective than both of the formulations of the M. anisopliae product, causing mortalities up to 79.8 and 71.6% in young and older larvae, respectively. The highest mortality rates of young and older larvae caused by the M. anisopliae product were 74.1 and 67.6% for the GR formulation, 70.2 and 61.8% for the EC formulation, respectively. These results may suggest that both fungi have potential to be used for management of P. fullo. PMID:25881632

  16. Genetic basis of destruxin production in the entomopathogen Metarhizium robertsii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Destruxins are among the most exhaustively researched secondary metabolites of entomopathogenic fungi, yet definitive evidence for their roles in pathogenicity and virulence has yet to be shown. To establish the genetic bases for the biosynthesis of this family of depsipeptides, we identified a 23,7...

  17. Potential applications of insect symbionts in biotechnology.

    PubMed

    Berasategui, Aileen; Shukla, Shantanu; Salem, Hassan; Kaltenpoth, Martin

    2016-02-01

    Symbiotic interactions between insects and microorganisms are widespread in nature and are often the source of ecological innovations. In addition to supplementing their host with essential nutrients, microbial symbionts can produce enzymes that help degrade their food source as well as small molecules that defend against pathogens, parasites, and predators. As such, the study of insect ecology and symbiosis represents an important source of chemical compounds and enzymes with potential biotechnological value. In addition, the knowledge on insect symbiosis can provide novel avenues for the control of agricultural pest insects and vectors of human diseases, through targeted manipulation of the symbionts or the host-symbiont associations. Here, we discuss different insect-microbe interactions that can be exploited for insect pest and human disease control, as well as in human medicine and industrial processes. Our aim is to raise awareness that insect symbionts can be interesting sources of biotechnological applications and that knowledge on insect ecology can guide targeted efforts to discover microorganisms of applied value. PMID:26659224

  18. Towards the elements of successful insect RNAi

    PubMed Central

    Scott, Jeffrey G.; Michel, Kristin; Bartholomay, Lyric; Siegfried, Blair D.; Hunter, Wayne B.; Smagghe, Guy; Zhu, Kun Yan; Douglas, Angela E.

    2013-01-01

    RNA interference (RNAi), the sequence-specific suppression of gene expression, offers great opportunities for insect science, especially to analyze gene function, manage pest populations, and reduce disease pathogens. The accumulating body of literature on insect RNAi has revealed that the efficiency of RNAi varies between different species, the mode of RNAi delivery, and the genes being targeted. There is also variation in the duration of transcript suppression. At present, we have a limited capacity to predict the ideal experimental strategy for RNAi of a particular gene/insect because of our incomplete understanding of whether and how the RNAi signal is amplified and spread among insect cells. Consequently, development of the optimal RNAi protocols is a highly empirical process. This limitation can be relieved by systematic analysis of the molecular physiological basis of RNAi mechanisms in insects. An enhanced conceptual understanding of RNAi function in insects will facilitate the application of RNAi for dissection of gene function, and to fast-track the application of RNAi to both control pests and develop effective methods to protect beneficial insects and non-insect arthropods, particularly the honey bee (Apis mellifera) and cultured Pacific white shrimp (Litopenaeus vannamei) from viral and parasitic diseases. PMID:24041495

  19. Book Review: Insect Virology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Viruses that infect insects have long been of interest both as a means for controlling insect pest populations in an environmentally safe manner, and also as significant threats to beneficial insects of great value, such as honey bees and silkworms. Insect viruses also have been of intrinsic intere...

  20. Insect-ual Pursuits.

    ERIC Educational Resources Information Center

    Mallow, David

    1991-01-01

    Explains how insects can be used to stimulate student writing. Describes how students can create their own systems to classify and differentiate insects. Discusses insect morphology and includes three detailed diagrams. The author provides an extension activity where students hypothesize about the niche of an insect based on its anatomy. (PR)

  1. An Introduction to Microbial Control of Insect Pests of Potato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite allelochemical defenses, potato is attacked by a multitude of invertebrate pests including insects, mites, slugs, and nematodes. Insects feed on every part of the plant (leaves, stems, and tubers) and several of these pests also serve as vectors of plant pathogens. Reliance on broad spectru...

  2. Chapter 11 Insect transmitted virus and mollicute disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect-transmitted diseases of maize are found throughout the maize growing regions of the world. These diseases are caused by viruses, phytoplasmas and spiroplasmas. The pathogens, vectors and plant hosts for the major insect-transmitted diseases of maize world-wide are reviewed. Factors leading to...

  3. Grooming Behavior as a Mechanism of Insect Disease Defense

    PubMed Central

    Zhukovskaya, Marianna; Yanagawa, Aya; Forschler, Brian T.

    2013-01-01

    Grooming is a well-recognized, multipurpose, behavior in arthropods and vertebrates. In this paper, we review the literature to highlight the physical function, neurophysiological mechanisms, and role that grooming plays in insect defense against pathogenic infection. The intricate relationships between the physical, neurological and immunological mechanisms of grooming are discussed to illustrate the importance of this behavior when examining the ecology of insect-pathogen interactions. PMID:26462526

  4. An insect pupal cell with antimicrobial properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil-dwelling insects have developed various defense mechanisms to defend against pathogen infection. The pecan weevil, Curculio caryae, spends two to three years in the soil inside an earthen cell. We hypothesized that the cell may possess antimicrobial properties. In a laboratory study, we teste...

  5. Development of Baits for Insect Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article outlines the importance of baits. Baits are formulations that can be used to deliver a toxic chemical or a pathogen (active agent) via ingestion to an insect pest with the goal of killing it. A bait formulations consist of a bait matrix which is the carrier for an active agent. The bait...

  6. Indirect effects of one plant pathogen on the transmission of a second pathogen and the behavior of its potato psyllid vector

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant pathogens can influence the behavior and performance of insect herbivore vectors. Studies of these associations typically focus on tripartite interactions between a plant host, a plant pathogen, and its insect vector. However, an unrelated herbivore or pathogen also could influence host-pathog...

  7. Insect prophenoloxidase: the view beyond immunity

    PubMed Central

    Lu, Anrui; Zhang, Qiaoli; Zhang, Jie; Yang, Bing; Wu, Kai; Xie, Wei; Luan, Yun-Xia; Ling, Erjun

    2014-01-01

    Insect prophenoloxidase (PPO) is an important innate immunity protein due to its involvement in cellular and humoral defense. It belongs to a group of type-3 copper-containing proteins that occurs in almost all organisms. Insect PPO has been studied for over a century, and the PPO activation cascade is becoming clearer. The insect PPO activation pathway incorporates several important proteins, including pattern-recognition receptors (PGRP, β GRP, and C-type lectins), serine proteases, and serine protease inhibitors (serpins). Due to their complexity, PPO activation mechanisms vary among insect species. Activated phenoloxidase (PO) oxidizes phenolic molecules to produce melanin around invading pathogens and wounds. The crystal structure of Manduca sexta PPO shows that a conserved amino acid, phenylalanine (F), can block the active site pocket. During activation, this blocker must be dislodged or even cleaved at the N-terminal sequence to expose the active site pockets and allow substrates to enter. Thanks to the crystal structure of M. sexta PPO, some domains and specific amino acids that affect PPO activities have been identified. Further studies of the relationship between PPO structure and enzyme activities will provide an opportunity to examine other type-3 copper proteins, and trace when and why their various physiological functions evolved. Recent researches show that insect PPO has a relationship with neuron activity, longevity, feces melanization (phytophagous insects) and development, which suggests that it is time for us to look back on insect PPO beyond the view of immunity in this review. PMID:25071597

  8. [Evaluation of the biological control potential of Metarhizium anisopliae toward Boophilus microplus in pen trials].

    PubMed

    Bahiense, Thiago C; Fernandes, Everton K K; Angelo, Isabele da C; Perinotto, Wendell M de S; Bittencourt, Vãnia R E P

    2007-01-01

    The aim of the present study was to evaluate the capacity of the fungus Metarhizium anisopliae to control Boophilus microplus tick in pen trials. Infested calves were held in individual pen and treated with fungus suspension through aspersion bath. The results were evaluated based on ticks' mortality rate for 28 days after treatment, and on the analysis of biology of tick's samples which were transferred to an incubation chamber. It was reported 33% of mortality during the total period analyzed, and the production of eggs and nutritional rates were decreased only for a short period after treatment. PMID:18373901

  9. Divergent and Convergent Evolution of Fungal Pathogenicity.

    PubMed

    Shang, Yanfang; Xiao, Guohua; Zheng, Peng; Cen, Kai; Zhan, Shuai; Wang, Chengshu

    2016-01-01

    Fungal pathogens of plants and animals have multifarious effects; they cause devastating damages to agricultures, lead to life-threatening diseases in humans, or induce beneficial effects by reducing insect pest populations. Many virulence factors have been determined in different fungal pathogens; however, the molecular determinants contributing to fungal host selection and adaptation are largely unknown. In this study, we sequenced the genomes of seven ascomycete insect pathogens and performed the genome-wide analyses of 33 species of filamentous ascomycete pathogenic fungi that infect insects (12 species), plants (12), and humans (9). Our results revealed that the genomes of plant pathogens encode more proteins and protein families than the insect and human pathogens. Unexpectedly, more common orthologous protein groups are shared between the insect and plant pathogens than between the two animal group pathogens. We also found that the pathogenicity of host-adapted fungi evolved multiple times, and that both divergent and convergent evolutions occurred during pathogen-host cospeciation thus resulting in protein families with similar features in each fungal group. However, the role of phylogenetic relatedness on the evolution of protein families and therefore pathotype formation could not be ruled out due to the effect of common ancestry. The evolutionary correlation analyses led to the identification of different protein families that correlated with alternate pathotypes. Particularly, the effector-like proteins identified in plant and animal pathogens were strongly linked to fungal host adaptation, suggesting the existence of similar gene-for-gene relationships in fungus-animal interactions that has not been established before. These results well advance our understanding of the evolution of fungal pathogenicity and the factors that contribute to fungal pathotype formation. PMID:27071652

  10. Laboratory mortality and mycosis of adult Curculio caryae (Coleoptera: Curculionidae) following application of Metarhizium anisopliae in the laboratory and field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pecan weevil, Curculio caryae, is a key pest of pecans. Our objective was to determine the potential of Metarhizium anisopliae to control emerging C. caryae adults. First, a laboratory test was conducted to compare four Beauveria bassiana strains (Bb GA2, BbLA3, BbMS1, and GHA) and three M. an...

  11. Effect of fermentation media on the production, efficacy and storage stability of Metarhizium brunneum microsclerotia formulated as a prototype granule

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New liquid fermentation techniques for the production of the bioinsecticidal fungus Metarhizium brunneum strain F-52 have resulted in the formation of microsclerotia (MS), a compact, melonized-hyphal structure capable of surviving desiccation and formulation as dry granules. When rehydrated, these M...

  12. Efficacy of Metarhizium anisopliae as a Curative Application for Black Vine Weevil (Otiorhynchus sulcatus) Infesting Container-Grown Nursery Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The black vine weevil (BVW), Otiorhynchus sulcatus (F.), is a serious pest of nursery crops. The fungus, Metarhizium anisopliae (F52), is registered by the US Environmental Protection Agency for BVW control. The objective of this study was to determine the efficacy of a curative drench application...

  13. Exposure of bed bugs to metarhizium anisopliae, and the effect of defensive secretions on fungal growth in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bed bugs Cimex lectularius were treated with conidia of the entomopathogenic fungus Metarhizium anisopliae by topical, spray, and contact exposure. One week post-exposure, inconsistent mortalities were observed, averaging 30% across all treatment groups and replicates. Microscopic examination of top...

  14. THE FUNGAL BIOPESTICIDE METARHIZIUM ANISOPLIAE HAS AN ADJUVANT EFFECT ON THE ALLERGIC RESPONSE TO OVALBUMIN IN MICE

    EPA Science Inventory

    Background: Sensitisation to cockroaches is associated with asthma and hence, the elimination of this vermin is of interest. Metarhizium anisopliae is a parasitic fungus used as a pesticide to control cockroach infestation indoors. Previously M. anisopliae has been shown to cause...

  15. Genome-assisted development of nuclear intergenic sequence markers for entomopathogenic fungi of the Metarhizium anisopliae species complex

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Entomopathogenic fungi in the genus Metarhizium have proven useful for the biological control of economically important pests across the globe. Understanding the true diversity of this group is hampered by convergent morphologies between species. The application of molecular techniques has enabled...

  16. Cover crop and conidia delivery system impacts on soil persistence of Metarhizium anisopliae (Hypocreales:Clavicipitaceae) in sugarbeet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sugarbeet root maggot, Tetanops myopaeformis (Röder), is a major North American pest of sugarbeet, Beta vulgaris L. Previous research suggests moderate field efficacy of the fungal entomopathogen Metarhizium anisopliae (Metch.) Sorok. against T. myopaeformis larvae. We conducted three-years of f...

  17. Insect Bites and Stings

    MedlinePlus

    Most insect bites are harmless, though they sometimes cause discomfort. Bee, wasp, and hornet stings and fire ant bites usually hurt. Mosquito and flea bites usually itch. Insects can also spread diseases. In the United States, ...

  18. Insects: An Interdisciplinary Unit

    ERIC Educational Resources Information Center

    Leger, Heather

    2007-01-01

    The author talks about an interdisciplinary unit on insects, and presents activities that can help students practice communication skills (interpersonal, interpretive, and presentational) and learn about insects with hands-on activities.

  19. Respiration in Aquatic Insects.

    ERIC Educational Resources Information Center

    MacFarland, John

    1985-01-01

    This article: (1) explains the respiratory patterns of several freshwater insects; (2) describes the differences and mechanisms of spiracular cutaneous, and gill respiration; and (3) discusses behavioral aspects of selected aquatic insects. (ML)

  20. Insects and Scorpions

    MedlinePlus

    ... gov . Workplace Safety and Health Topics Insects & Scorpions Bees, Wasps, and Hornets Fire Ants Scorpions Additional Resources ... to outdoor workers. Stinging or biting insects include bees, wasps, hornets, and fire ants. The health effects ...

  1. Ecophysiology and insect herbivory

    SciTech Connect

    Clancy, K.M.; Wagner, M.R.; Reich, P.B.

    1995-07-01

    The relationship of insect herbivory to conifer physiology is examined. Aspects of nutrient assimilation, nutrient distribution, water stress, and climatic change are correlated to defoliation by insects. Other factors examined include plant age, density, structure, soils, and plant genotype.

  2. Comparison of water, oils and emulsifiable adjuvant oils as formulating agents for Metarhizium anisopliae for use in control of Boophilus microplus.

    PubMed

    Polar, Perry; Kairo, Moses T K; Moore, Dave; Pegram, Rupert; John, Sally-Ann

    2005-09-01

    Studies were conducted to identify oil-based formulating agents (paraffinic oil, palm oil and emulsifiable adjuvant oils (EAOs)) for Metarhizium anisopliae that were superior to water with simple surfactants using a germination test and a bioassay against Boophilus microplus. Germination of conidia in all formulations, except 10% coconut EAO, produced more than 68% germination at 24 h and nearly 100% at 48 h. Coconut oil (average survival time (AST) = 4.6 +/- 0.28 days) and 10% liquid paraffin EAO (AST = 4.4 +/- 0.15 days) enhanced the pathogenicity of M. anisopliae to B. microplus relative to water (AST = 8.4 +/- 0.42 days). M. anisopliae in 10% liquid paraffin EAO was the most effective formulation having a moderately high germination after 24 h and a low AST as well as a high AST in the control. In the second experiment, germination of conidia in 2% liquid paraffin EAO and 2% Cropspray was higher than in 2% Codacide oil at 24 h, however, all treatments reached 100% germination after 48 h. The ASTs of the EAO based M. anisopliae formulations (Average AST = 6.4 +/- 0.54 days) were similar but lower that the ASTs of the controls (Average AST = 9.6 +/- 0.28 days). PMID:16170611

  3. Laser system for identification, tracking, and control of flying insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flying insects are common vectors for transmission of pathogens and inflict significant harm on humans in large parts of the developing world. Besides the direct impact to humans, these pathogens also cause harm to crops and result in agricultural losses. Here, we present a laser-based system that c...

  4. Specific diversity of the entomopathogenic fungi Beauveria and Metarhizium in Mexican agricultural soils.

    PubMed

    Pérez-González, Víctor H; Guzmán-Franco, Ariel W; Alatorre-Rosas, Raquel; Hernández-López, Jorge; Hernández-López, Antonio; Carrillo-Benítez, María G; Baverstock, Jason

    2014-06-01

    Prior knowledge of the local population structure of entomopathogenic fungi is considered an important requisite when developing microbial control strategies against major pests of crops such as white grubs. An extensive survey in the estate of Guanajuato, one of the main agricultural regions of Mexico, was carried out to determine the abundance and diversity of entomopathogenic fungi in soil. Soil collected from 11 locations was baited for entomopathogenic fungi using Galleria mellonella. In addition, all isolates were morphologically identified and selected isolates of Beauveria and Metarhizium isolates identified using Bloc and ITS or Elongation Factor 1-α and ITS sequence information respectively. Genotypic diversity was then studied using microsatellite genotyping. The proportion of isolates belonging to each genus varied amongst all locations. The species Beauveria bassiana, B. pseudobassiana and Metarhizium robertsii were found, with B. bassiana being the most abundant and widely distributed. Microsatellite genotyping showed that the 36 B. bassiana isolates were grouped in 29 unique haplotypes, but with no separation according to geographical origin. PMID:24769124

  5. Acoustic Monitoring of Insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Farmers, grain elevator managers, and food processors often sample grain for insect damaged kernels and numbers of live adult insects but these easily obtained measurements of insect levels do not provide reliable estimates of the typically much larger populations of internally feeding immature inse...

  6. Exploring Sound with Insects

    ERIC Educational Resources Information Center

    Robertson, Laura; Meyer, John R.

    2010-01-01

    Differences in insect morphology and movement during singing provide a fascinating opportunity for students to investigate insects while learning about the characteristics of sound. In the activities described here, students use a free online computer software program to explore the songs of the major singing insects and experiment with making…

  7. Insects and Spiders.

    ERIC Educational Resources Information Center

    National Audubon Society, New York, NY.

    This set of teaching aids consists of nine Audubon Nature Bulletins, providing teachers and students with informational reading on insects and spiders. The bulletins have these titles: What Good Are Insects, How Insects Benefit Man, Life of the Honey Bee, Ants and Their Fascinating Ways, Mosquitoes and Other Flies, Caterpillars, Spiders and Silk,…

  8. Insects and Others.

    ERIC Educational Resources Information Center

    Mills, Richard

    1984-01-01

    Several ideas for observing insects and soil animals in the classroom are provided. Also provided are: (1) procedures for making insect cages with milk cartons; (2) suggestions for collecting and feeding insects; and (3) techniques for collecting and identifying soil animals. (BC)

  9. Interdisciplinary Outdoor Education, Insects.

    ERIC Educational Resources Information Center

    Orsborn, Edward E.

    This manual is a teacher's resource and guide book describing activities for elementary students involving the collecting, killing, preserving, and identification of insects. Most activities relate to collecting and identifying, but activities involving terrariums and hatcheries, finding hidden insects, and insect trapping are also described.…

  10. Sunflower insect pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Like other annual crops, sunflowers are fed upon by a variety of insect pests capable of reducing yields. Though there are a few insects which are considered consistent or severe (e.g., sunflower moth, banded sunflower moth, red sunflower seed weevil), many more insects are capable of causing proble...

  11. InsectBase: a resource for insect genomes and transcriptomes.

    PubMed

    Yin, Chuanlin; Shen, Gengyu; Guo, Dianhao; Wang, Shuping; Ma, Xingzhou; Xiao, Huamei; Liu, Jinding; Zhang, Zan; Liu, Ying; Zhang, Yiqun; Yu, Kaixiang; Huang, Shuiqing; Li, Fei

    2016-01-01

    The genomes and transcriptomes of hundreds of insects have been sequenced. However, insect community lacks an integrated, up-to-date collection of insect gene data. Here, we introduce the first release of InsectBase, available online at http://www.insect-genome.com. The database encompasses 138 insect genomes, 116 insect transcriptomes, 61 insect gene sets, 36 gene families of 60 insects, 7544 miRNAs of 69 insects, 96,925 piRNAs of Drosophila melanogaster and Chilo suppressalis, 2439 lncRNA of Nilaparvata lugens, 22,536 pathways of 78 insects, 678,881 untranslated regions (UTR) of 84 insects and 160,905 coding sequences (CDS) of 70 insects. This release contains over 12 million sequences and provides search functionality, a BLAST server, GBrowse, insect pathway construction, a Facebook-like network for the insect community (iFacebook), and phylogenetic analysis of selected genes. PMID:26578584

  12. InsectBase: a resource for insect genomes and transcriptomes

    PubMed Central

    Yin, Chuanlin; Shen, Gengyu; Guo, Dianhao; Wang, Shuping; Ma, Xingzhou; Xiao, Huamei; Liu, Jinding; Zhang, Zan; Liu, Ying; Zhang, Yiqun; Yu, Kaixiang; Huang, Shuiqing; Li, Fei

    2016-01-01

    The genomes and transcriptomes of hundreds of insects have been sequenced. However, insect community lacks an integrated, up-to-date collection of insect gene data. Here, we introduce the first release of InsectBase, available online at http://www.insect-genome.com. The database encompasses 138 insect genomes, 116 insect transcriptomes, 61 insect gene sets, 36 gene families of 60 insects, 7544 miRNAs of 69 insects, 96 925 piRNAs of Drosophila melanogaster and Chilo suppressalis, 2439 lncRNA of Nilaparvata lugens, 22 536 pathways of 78 insects, 678 881 untranslated regions (UTR) of 84 insects and 160 905 coding sequences (CDS) of 70 insects. This release contains over 12 million sequences and provides search functionality, a BLAST server, GBrowse, insect pathway construction, a Facebook-like network for the insect community (iFacebook), and phylogenetic analysis of selected genes. PMID:26578584

  13. Divergent and Convergent Evolution of Fungal Pathogenicity

    PubMed Central

    Shang, Yanfang; Xiao, Guohua; Zheng, Peng; Cen, Kai; Zhan, Shuai; Wang, Chengshu

    2016-01-01

    Fungal pathogens of plants and animals have multifarious effects; they cause devastating damages to agricultures, lead to life-threatening diseases in humans, or induce beneficial effects by reducing insect pest populations. Many virulence factors have been determined in different fungal pathogens; however, the molecular determinants contributing to fungal host selection and adaptation are largely unknown. In this study, we sequenced the genomes of seven ascomycete insect pathogens and performed the genome-wide analyses of 33 species of filamentous ascomycete pathogenic fungi that infect insects (12 species), plants (12), and humans (9). Our results revealed that the genomes of plant pathogens encode more proteins and protein families than the insect and human pathogens. Unexpectedly, more common orthologous protein groups are shared between the insect and plant pathogens than between the two animal group pathogens. We also found that the pathogenicity of host-adapted fungi evolved multiple times, and that both divergent and convergent evolutions occurred during pathogen–host cospeciation thus resulting in protein families with similar features in each fungal group. However, the role of phylogenetic relatedness on the evolution of protein families and therefore pathotype formation could not be ruled out due to the effect of common ancestry. The evolutionary correlation analyses led to the identification of different protein families that correlated with alternate pathotypes. Particularly, the effector-like proteins identified in plant and animal pathogens were strongly linked to fungal host adaptation, suggesting the existence of similar gene-for-gene relationships in fungus–animal interactions that has not been established before. These results well advance our understanding of the evolution of fungal pathogenicity and the factors that contribute to fungal pathotype formation. PMID:27071652

  14. Dosage response mortality of Japanese beetle, masked chafer, and June beetle (Coleoptera: Scarabaeidae) adults when exposed to experimental and commercially available granules containing Metarhizium brunneum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adult beetles of three different white grub species, Japanese beetle, Popillia japonica, June beetle, Phyllophaga spp., and masked chafer, Cyclocephala spp. were exposed to experimental and commercially available granules containing Metarhizium brunneum (Petch) strain F52, to determine susceptibilit...

  15. Optimization of compatible non-ionic surfactant for formulation development of hydrophobic conidia of entomopathogenic fungi, Beauveria bassiana (Hypocreales:Cordycipitaceae) and Metarhizium anisopliae Hypocreales:Clavicipita

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerial conidia, especially dried conidia of entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae are hydrophobic, and therefore surfactants are needed for developing water-based formulations in laboratory studies, greenhouse bioassays, and field trials as well as commercial product ...

  16. The Impact of Culture Age, Aeration, and Agitation on the Production of Microsclerotia of the Entomopathogenic Fungus Metarhizium anisopliae Using 100-Liter Fermentors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microsclerotia are desiccation-tolerant, compact hyphal aggregates produced by numerous fungi as overwintering structures. We recently discovered that the entomopathogenic fungus Metarhizium anisopliae produced microsclerotia during liquid culture fermentation. When air-dried microsclerotial granu...

  17. Digital PCR for detection of citrus pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus trees are often infected with multiple pathogens of economic importance, especially those with insect or mite vectors. Real-time/quantitative PCR (qPCR) has been used for high-throughput detection and relative quantification of pathogens; however, target reference or standards are required. I...

  18. Gut immunity in Lepidopteran insects.

    PubMed

    Wu, Kai; Yang, Bing; Huang, Wuren; Dobens, Leonard; Song, Hongsheng; Ling, Erjun

    2016-11-01

    Lepidopteran insects constitute one of the largest fractions of animals on earth, but are considered pests in their relationship with man. Key to the success of this order of insects is its ability to digest food and absorb nutrition, which takes place in the midgut. Because environmental microorganisms can easily enter Lepidopteran guts during feeding, the innate immune response guards against pathogenic bacteria, virus and microsporidia that can be devoured with food. Gut immune responses are complicated by both resident gut microbiota and the surrounding peritrophic membrane and are distinct from immune responses in the body cavity, which depend on the function of the fat body and hemocytes. Due to their relevance to agricultural production, studies of Lepidopteran insect midgut and immunity are receiving more attention, and here we summarize gut structures and functions, and discuss how these confer immunity against different microorganisms. It is expected that increased knowledge of Lepidopteran gut immunity may be utilized for pest biological control in the future. PMID:26872544

  19. The diversity of insect antiviral immunity: insights from viruses.

    PubMed

    Marques, João T; Imler, Jean-Luc

    2016-08-01

    Insects represent over 70% of all animal species. Recent virome analyses reveal unprecedented genetic diversity of insect viruses, which appears to match that of their hosts. Thus, insect-virus interactions may provide information on a vast repertoire of antiviral immune mechanisms. Tapping into this diversity is challenging because of several constraints imposed by the uniqueness of each insect model. Nevertheless, it is clear that many conserved and divergent pathways participate in the control of viral infection in insects. Co-evolution between hosts and viruses favors the development of immune evasion mechanisms by the pathogen. Viral suppressors can offer unique perspective on host pathways and emphasize the importance of RNA interference, apoptosis, but also NF-κB pathways and translation control in insect antiviral immunity. PMID:27232381

  20. Insect Barcode Information System

    PubMed Central

    Pratheepa, Maria; Jalali, Sushil Kumar; Arokiaraj, Robinson Silvester; Venkatesan, Thiruvengadam; Nagesh, Mandadi; Panda, Madhusmita; Pattar, Sharath

    2014-01-01

    Insect Barcode Information System called as Insect Barcode Informática (IBIn) is an online database resource developed by the National Bureau of Agriculturally Important Insects, Bangalore. This database provides acquisition, storage, analysis and publication of DNA barcode records of agriculturally important insects, for researchers specifically in India and other countries. It bridges a gap in bioinformatics by integrating molecular, morphological and distribution details of agriculturally important insects. IBIn was developed using PHP/My SQL by using relational database management concept. This database is based on the client– server architecture, where many clients can access data simultaneously. IBIn is freely available on-line and is user-friendly. IBIn allows the registered users to input new information, search and view information related to DNA barcode of agriculturally important insects.This paper provides a current status of insect barcode in India and brief introduction about the database IBIn. Availability http://www.nabg-nbaii.res.in/barcode PMID:24616562

  1. On-host control of the brown dog tick Rhipicephalus sanguineus Latreille (Acari: Ixodidae) by Metarhizium brunneum (Hypocreales: Clavicipitaceae).

    PubMed

    Rot, A; Gindin, G; Ment, D; Mishoutchenko, A; Glazer, I; Samish, M

    2013-03-31

    Ticks are obligatory blood-sucking arthropods. Their life cycle includes a relatively short period of feeding on a vertebrate host and a long off-host period spent in the upper layer of the soil. Entomopathogenic fungi are known to be highly effective tick pathogens and the on-host application of these fungi may be a promising economic approach for tick control. In this study, we evaluated the tick control provided by spraying Metarhizium brunneum onto the tick's vertebrate host, specifically gerbils (Meriones tristrami) and rabbits (Oryctolagus cuniculus). The efficacy of the fungal treatment was not limited to a direct effect on the mortality of feeding ticks, but continued during molting (off host) and, in the case of female ticks, the treatment reduced the production of eggs and their hatching rate. The direct control of the on-host stages was relatively low (from 19 to 38%); whereas the effects of the applied fungus on subsequent tick development reduced the yield of the following engorged stages up to 30-63%. Engorged females that dropped from rabbits sprayed with M. brunneum laid 21.5% fewer eggs than the control females. Moreover, these ticks transmitted conidia by contact to the eggs which they laid, resulting a 3-fold reduction in the rate of hatching relative to the control. Based on theoretical cumulative calculations, these results suggest that if the progeny of each unfed stage feed on fungus-sprayed hosts, there will be a 92% reduction in the tick population within one generation. Two spray formulations, one based on mineral oil and another based on a starch-sucrose mixture, significantly enhanced on-host tick control, in comparison with an unformulated conidial suspension. The reduction in the number of nymphs that fed on the treated host and later developed into unfed adults was 54.9% for unformulated conidia, 70.4% for the oil formulation and 86.4% for the starch-sucrose formulation. Increasing the environmental humidity around the gerbils while

  2. Molecular Genetics of Beauveria bassiana Infection of Insects.

    PubMed

    Ortiz-Urquiza, A; Keyhani, N O

    2016-01-01

    Research on the insect pathogenic filamentous fungus, Beauveria bassiana has witnessed significant growth in recent years from mainly physiological studies related to its insect biological control potential, to addressing fundamental questions regarding the underlying molecular mechanisms of fungal development and virulence. This has been in part due to a confluence of robust genetic tools and genomic resources for the fungus, and recognition of expanded ecological interactions with which the fungus engages. Beauveria bassiana is a broad host range insect pathogen that has the ability to form intimate symbiotic relationships with plants. Indeed, there is an increasing realization that the latter may be the predominant environmental interaction in which the fungus participates, and that insect parasitism may be an opportunist lifestyle evolved due to the carbon- and nitrogen-rich resources present in insect bodies. Here, we will review progress on the molecular genetics of B. bassiana, which has largely been directed toward identifying genetic pathways involved in stress response and virulence assumed to have practical applications in improving the insect control potential of the fungus. Important strides have also been made in understanding aspects of B. bassiana development. Finally, although increasingly apparent in a number of studies, there is a need for progressing beyond phenotypic mutant characterization to sufficiently investigate the molecular mechanisms underlying B. bassiana's unique and diverse lifestyles as saprophyte, insect pathogen, and plant mutualist. PMID:27131326

  3. The Interaction of Human Enteric Pathogens with Plants

    PubMed Central

    Lim, Jeong-A; Lee, Dong Hwan; Heu, Sunggi

    2014-01-01

    There are an increasing number of outbreaks of human pathogens related to fresh produce. Thus, the growth of human pathogens on plants should be explored. Human pathogens can survive under the harsh environments in plants, and can adhere and actively invade plants. Plant-associated microbiota or insects contribute to the survival and transmission of enteric pathogens in plants. Human enteric pathogens also trigger plant innate immunity, but some pathogens–such as Salmonella–can overcome this defense mechanism. PMID:25288993

  4. Transmission and retention of Salmonella enterica by phytophagous hemipteran insects.

    PubMed

    Soto-Arias, José Pablo; Groves, Russell L; Barak, Jeri D

    2014-09-01

    Several pest insects of human and livestock habitations are known as vectors of Salmonella enterica; however, the role of plant-feeding insects as vectors of S. enterica to agricultural crops remains unexamined. Using a hemipteran insect pest-lettuce system, we investigated the potential for transmission and retention of S. enterica. Specifically, Macrosteles quadrilineatus and Myzus persicae insects were fed S. enterica-inoculated lettuce leaf discs or artificial liquid diets confined in Parafilm sachets to allow physical contact or exclusively oral ingestion of the pathogen, respectively. After a 24-h acquisition access period, insects were moved onto two consecutive noninoculated leaf discs or liquid diets and allowed a 24-h inoculation access period on each of the two discs or sachets. Similar proportions of individuals from both species ingested S. enterica after a 24-h acquisition access period from inoculated leaf discs, but a significantly higher proportion of M. quadrilineatus retained the pathogen internally after a 48-h inoculation access period. S. enterica was also recovered from the honeydew of both species. After a 48-h inoculation access period, bacteria were recovered from a significantly higher proportion of honeydew samples from M. quadrilineatus than from M. persicae insects. The recovery of S. enterica from leaf discs and liquid diets postfeeding demonstrated that both species of insects were capable of transmitting the bacteria in ways that are not limited to mechanical transmission. Overall, these results suggest that phytophagous insects may serve as potential vectors of S. enterica in association with plants. PMID:24973069

  5. Transmission and Retention of Salmonella enterica by Phytophagous Hemipteran Insects

    PubMed Central

    Soto-Arias, José Pablo; Groves, Russell L.

    2014-01-01

    Several pest insects of human and livestock habitations are known as vectors of Salmonella enterica; however, the role of plant-feeding insects as vectors of S. enterica to agricultural crops remains unexamined. Using a hemipteran insect pest-lettuce system, we investigated the potential for transmission and retention of S. enterica. Specifically, Macrosteles quadrilineatus and Myzus persicae insects were fed S. enterica-inoculated lettuce leaf discs or artificial liquid diets confined in Parafilm sachets to allow physical contact or exclusively oral ingestion of the pathogen, respectively. After a 24-h acquisition access period, insects were moved onto two consecutive noninoculated leaf discs or liquid diets and allowed a 24-h inoculation access period on each of the two discs or sachets. Similar proportions of individuals from both species ingested S. enterica after a 24-h acquisition access period from inoculated leaf discs, but a significantly higher proportion of M. quadrilineatus retained the pathogen internally after a 48-h inoculation access period. S. enterica was also recovered from the honeydew of both species. After a 48-h inoculation access period, bacteria were recovered from a significantly higher proportion of honeydew samples from M. quadrilineatus than from M. persicae insects. The recovery of S. enterica from leaf discs and liquid diets postfeeding demonstrated that both species of insects were capable of transmitting the bacteria in ways that are not limited to mechanical transmission. Overall, these results suggest that phytophagous insects may serve as potential vectors of S. enterica in association with plants. PMID:24973069

  6. Mycoplasmas, plants, insect vectors: a matrimonial triangle.

    PubMed

    Garnier, M; Foissac, X; Gaurivaud, P; Laigret, F; Renaudin, J; Saillard, C; Bové, J M

    2001-10-01

    Plant pathogenic mycoplasmas were discovered by electron microscopy, in 1967, long after the discovery and culture in 1898 of the first pathogenic mycoplasma of animal origin, Mycoplasma mycoides. Mycoplasmas are Eubacteria of the class Mollicutes, a group of organisms phylogenetically related to Gram-positive bacteria. Their more characteristic features reside in the small size of their genomes, the low guanine (G) plus cytosine (C) content of their genomic DNA and the lack of a cell wall. Plant pathogenic mycoplasmas are responsible for several hundred diseases and belong to two groups: the phytoplasmas and the spiroplasmas. The phytoplasmas (previously called MLOs, for mycoplasma like organisms) were discovered first; they are pleiomorphic, and have so far resisted in vitro cultivation. Phytoplasmas represent the largest group of plant pathogenic Mollicutes. Only three plant pathogenic spiroplasmas are known today. Spiroplasma citri, the agent of citrus stubborn was discovered and cultured in 1970 and shown to be helical and motile. S. kunkelii is the causal agent of corn stunt. S. phoeniceum, responsible for periwinkle yellows, was discovered in Syria. There are many other spiroplasmas associated with insects and ticks. Plant pathogenic mycoplasmas are restricted to the phloem sieve tubes in which circulates the photosynthetically-enriched sap, the food for many phloem-feeding insects (aphids, leafhoppers, psyllids, etc.). Interestingly, phytopathogenic mycoplasmas are very specifically transmitted by leafhoppers or psyllid species. In this paper, the most recent knowledge on phytopathogenic mycoplasmas in relation with their insect and plant habitats is presented as well as the experiments carried out to control plant mycoplasma diseases, by expression of mycoplasma-directed-antibodies in plants (plantibodies). PMID:11570280

  7. Exposure of Metarhizium acridum mycelium to light induces tolerance to UV-B radiation.

    PubMed

    Brancini, Guilherme T P; Rangel, Drauzio E N; Braga, Gilberto Ú L

    2016-03-01

    Metarhizium acridum is an entomopathogenic fungus commonly used as a bioinsecticide. The conidium is the fungal stage normally employed as field inoculum in biological control programs and must survive under field conditions such as high ultraviolet-B (UV-B) exposure. Light, which is an important stimulus for many fungi, has been shown to induce the production of M. robertsii conidia with increased stress tolerance. Here we show that a two-hour exposure to white or blue/UV-A light of fast-growing mycelium induces tolerance to subsequent UV-B irradiation. Red light, however, does not have the same effect. In addition, we established that this induction can take place with as little as 1 min of white-light exposure. This brief illumination scheme could be relevant in future studies of M. acridum photobiology and for the production of UV-B resistant mycelium used in mycelium-based formulations for biological control. PMID:26884481

  8. Production of microsclerotia by Brazilian strains of Metarhizium spp. using submerged liquid culture fermentation.

    PubMed

    Mascarin, Gabriel Moura; Kobori, Nilce Naomi; de Jesus Vital, Rayan Carlos; Jackson, Mark Alan; Quintela, Eliane Dias

    2014-05-01

    We investigated the potential production and desiccation tolerance of microsclerotia (MS) by Brazilian strains of Metarhizium anisopliae (Ma), M. acridum (Mc) and M. robertsii (Mr). These fungi were grown in a liquid medium containing 16 g carbon l⁻¹ with a carbon:nitrogen ratio of 50:1. One hundred milliliters cultures were grown in 250 ml Erlenmeyer flasks in a rotary incubator shaker at 28 °C and 200 rpm for 5 days. Five-day-old MS were harvested, mixed with diatomaceous earth (DE) and air-dried for 2 days at 30 °C. The air-dried MS-DE granular preparations were milled by mortar + pestle and stored in centrifuged tubes at either 26 or -20 °C. Desiccation tolerance and conidia production were assessed for dried MS granules by measuring hyphal germination after incubation for 2 days on water agar plates at 26 °C and for conidia production following 7 days incubation. Yields of MS by all strains of Metarhizium were 6.1-7.3 × 10⁶ l⁻¹ after 3 days growth with maximum MS yields (0.7-1.1 × 10⁷ l⁻¹) after 5 days growth. No differences in biomass accumulation were observed after 3 days growth, whereas Ma-CG168 showed the highest biomass accumulation after 5 days growth. Dried MS-DE preparations of all fungal strains were equally tolerant to desiccation (≥93 % germination) and the highest conidia production was obtained by MS granules of Mc-CG423 (4 × 10⁹ conidia g⁻¹). All MS granules showed similar stability after storage at either 26 or -20 °C for 3.5 months. PMID:24343780

  9. Host-pathogen interactions and genome evolution in two generalist and specialist microsporidian pathogens of mosquitoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The adaptation of two distantly related microsporidia to their mosquito hosts was investigated. Edhazardia aedis is a specialist pathogen that infects Aedes aegypti, the main vector of dengue and yellow fever arboviruses. Vavraia culicis is a generalist pathogen of several insects including Anophele...

  10. Characterization of the Relative Abundance of the Citrus Pathogen Ca. Liberibacter Asiaticus in the Microbiome of Its Insect Vector, Diaphorina citri, using High Throughput 16S rRNA Sequencing

    PubMed Central

    Fagen, Jennie R; Giongo, Adriana; Brown, Christopher T; Davis-Richardson, Austin G; Gano, Kelsey A; Triplett, Eric W

    2012-01-01

    The relationship between the causal agent of Huanglongbing (HLB), Ca. Liberibacter asiaticus(Las), and the naturally occurring endosymbiotic community of its insect vector, the Asian citrus psyllid (ACP), Diaphorina citri, was studied. Variation was observed in the titer of Las within an ACP population feeding on the same material. The cause of this disparity is unknown, and has implications for Las transmission and the spread of HLB. This study utilizes culture independent methods to establish the relationship between the ACP’s microbial community and Las acquisition. DNA from 21 psyllids was amplified using universal 16S rRNA primers with Illumina adaptor regions and a sample-specific 7- base identifier. These amplicons were then batch-sequenced on the Illumina platform. The resulting sequences were separated by the identifier, and compared to known sequences in a 16S rRNA database. The microbial communities of each psyllid were compared to determine whether a correlation exists between the ACP’s endosymbionts and level of Las acquisition. ACPs were dominated by the same four bacterialgenera regardless of the abundance of Ca.Liberibacter. A combination of qPCR and Illumina sequencing was used to establish an infection gradient among the sampled ACPs. The Ca. Liberibacter titer within the insect was found to have a strong negative relationship with an endosymbiont residing in the syncytium of the mycetocyte and a positive relationship with Wolbachia. These correlations have implications in the acquisition of Las by the ACP as well as the activities of Las within this vector. PMID:22529882

  11. Anti-pathogen protection versus survival costs mediated by an ectosymbiont in an ant host.

    PubMed

    Konrad, Matthias; Grasse, Anna V; Tragust, Simon; Cremer, Sylvia

    2015-01-22

    The fitness effects of symbionts on their hosts can be context-dependent, with usually benign symbionts causing detrimental effects when their hosts are stressed, or typically parasitic symbionts providing protection towards their hosts (e.g. against pathogen infection). Here, we studied the novel association between the invasive garden ant Lasius neglectus and its fungal ectosymbiont Laboulbenia formicarum for potential costs and benefits. We tested ants with different Laboulbenia levels for their survival and immunity under resource limitation and exposure to the obligate killing entomopathogen Metarhizium brunneum. While survival of L. neglectus workers under starvation was significantly decreased with increasing Laboulbenia levels, host survival under Metarhizium exposure increased with higher levels of the ectosymbiont, suggesting a symbiont-mediated anti-pathogen protection, which seems to be driven mechanistically by both improved sanitary behaviours and an upregulated immune system. Ants with high Laboulbenia levels showed significantly longer self-grooming and elevated expression of immune genes relevant for wound repair and antifungal responses (β-1,3-glucan binding protein, Prophenoloxidase), compared with ants carrying low Laboulbenia levels. This suggests that the ectosymbiont Laboulbenia formicarum weakens its ant host by either direct resource exploitation or the costs of an upregulated behavioural and immunological response, which, however, provides a prophylactic protection upon later exposure to pathogens. PMID:25473011

  12. Anti-pathogen protection versus survival costs mediated by an ectosymbiont in an ant host

    PubMed Central

    Konrad, Matthias; Grasse, Anna V.; Tragust, Simon; Cremer, Sylvia

    2015-01-01

    The fitness effects of symbionts on their hosts can be context-dependent, with usually benign symbionts causing detrimental effects when their hosts are stressed, or typically parasitic symbionts providing protection towards their hosts (e.g. against pathogen infection). Here, we studied the novel association between the invasive garden ant Lasius neglectus and its fungal ectosymbiont Laboulbenia formicarum for potential costs and benefits. We tested ants with different Laboulbenia levels for their survival and immunity under resource limitation and exposure to the obligate killing entomopathogen Metarhizium brunneum. While survival of L. neglectus workers under starvation was significantly decreased with increasing Laboulbenia levels, host survival under Metarhizium exposure increased with higher levels of the ectosymbiont, suggesting a symbiont-mediated anti-pathogen protection, which seems to be driven mechanistically by both improved sanitary behaviours and an upregulated immune system. Ants with high Laboulbenia levels showed significantly longer self-grooming and elevated expression of immune genes relevant for wound repair and antifungal responses (β-1,3-glucan binding protein, Prophenoloxidase), compared with ants carrying low Laboulbenia levels. This suggests that the ectosymbiont Laboulbenia formicarum weakens its ant host by either direct resource exploitation or the costs of an upregulated behavioural and immunological response, which, however, provides a prophylactic protection upon later exposure to pathogens. PMID:25473011

  13. Acoustic communication in insect disease vectors

    PubMed Central

    Vigoder, Felipe de Mello; Ritchie, Michael Gordon; Gibson, Gabriella; Peixoto, Alexandre Afranio

    2013-01-01

    Acoustic signalling has been extensively studied in insect species, which has led to a better understanding of sexual communication, sexual selection and modes of speciation. The significance of acoustic signals for a blood-sucking insect was first reported in the XIX century by Christopher Johnston, studying the hearing organs of mosquitoes, but has received relatively little attention in other disease vectors until recently. Acoustic signals are often associated with mating behaviour and sexual selection and changes in signalling can lead to rapid evolutionary divergence and may ultimately contribute to the process of speciation. Songs can also have implications for the success of novel methods of disease control such as determining the mating competitiveness of modified insects used for mass-release control programs. Species-specific sound “signatures” may help identify incipient species within species complexes that may be of epidemiological significance, e.g. of higher vectorial capacity, thereby enabling the application of more focussed control measures to optimise the reduction of pathogen transmission. Although the study of acoustic communication in insect vectors has been relatively limited, this review of research demonstrates their value as models for understanding both the functional and evolutionary significance of acoustic communication in insects. PMID:24473800

  14. Effects of ingested vertebrate-derived factors on insect immune responses

    PubMed Central

    Pakpour, Nazzy; Riehle, Michael A.; Luckhart, Shirley

    2014-01-01

    During the process of blood feeding insect vectors are exposed to an array of vertebrate-derived blood factors ranging from byproducts of blood meal digestion to naturally occurring products in the blood including growth hormones, cytokines and factors derived from blood-borne pathogens themselves. In this review, we examine the ability of these ingested vertebrate blood factors to alter the innate pathogen defenses of insect vectors. The ability of these factors to modify the immune responses of insect vectors offers new intriguing targets for blocking or reducing transmission of human disease-causing pathogens. PMID:25401083

  15. Bloodborne pathogens

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000453.htm Bloodborne pathogens To use the sharing features on this page, please enable JavaScript. A pathogen is something that causes disease. Germs that can ...

  16. Endosymbiotic bacteria in insects: guardians of the immune system?

    PubMed Central

    Eleftherianos, Ioannis; Atri, Jaishri; Accetta, Julia; Castillo, Julio C.

    2013-01-01

    Insects have evolved obligate, mutualistic interactions with bacteria without further transmission to other eukaryotic organisms. Such long-term obligate partnerships between insects and bacteria have a profound effect on various physiological functions of the host. Here we provide an overview of the effects of endosymbiotic bacteria on the insect immune system as well as on the immune response of insects to pathogenic infections. Potential mechanisms through which endosymbionts can affect the ability of their host to resist an infection are discussed in the light of recent findings. We finally point out unresolved questions for future research and speculate how the current knowledge can be employed to design and implement measures for the effective control of agricultural insect pests and vectors of diseases. PMID:23508299

  17. Sterile Insect Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter discusses the history of the development of quality control tchnology, the principles and philosophy of assessing insect quality, and the relative importance of the various parameters used to assess insect quality in the context of mass-rearing for the SIT. Quality control is most devel...

  18. Corazonin in insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corazonin is a peptidergic neurohormone of insects which is expressed in neurosecretory neurons of the pars lateralis of the protocerebrum and transported via nervi corpus cardiaci in the storage lobes of the corpora cardiaca. This peptide occurs with a single isofomr in all insects studied so far,...

  19. Insects: Bugged Out!

    ERIC Educational Resources Information Center

    Piehl, Kathy

    2011-01-01

    Insects really need no introduction. They have lived on earth much longer than humans and vastly outnumber people and all other animal species combined. People encounter them daily in their houses and yards. Yet, when children want to investigate insects, books can help them start their explorations. "Paleo Bugs" carries readers back to the time…

  20. Insects and Bugs

    ERIC Educational Resources Information Center

    Sutherland, Karen

    2009-01-01

    They have been around for centuries. They sting, they bite. They cause intense itching or painful sores. They even cause allergic reactions and sometimes death. There are two types of insects that are pests to humans--those that sting and those that bite. The insects that bite do so with their mouths and include mosquitoes, chiggers, and ticks.…

  1. Sugarcane insect update

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect are an important group of pests affecting sugarcane production. Agricultural consultants play an important role is assisting sugarcane farmers to choose the most appropriated means of managing damaging infestations of insects in their crop. In this presentation, information will be presented ...

  2. Effects on Insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of controlled and modified atmospheres on insects is reviewed and summarized in this chapter. Traditionally, controlled and modified atmospheres are used to store and preserve fresh fruits and vegetables. The effects on insects and the potential of these treatments are secondary to the...

  3. Principal Areas of Insect Research

    ERIC Educational Resources Information Center

    Williams, Carroll M.

    1973-01-01

    Research for insect control has been quite complex. However, recent knowledge of using insect hormones against them has opened new vistas for producing insecticides which may be harmless to human population. Current areas of insect research are outlined. (PS)

  4. A role for insect galectins in parasite survival.

    PubMed

    Kamhawi, Shaden; Ramalho-Ortigao, Marcelo; Pham, Van M; Kumar, Sanjeev; Lawyer, Phillip G; Turco, Salvatore J; Barillas-Mury, Carolina; Sacks, David L; Valenzuela, Jesus G

    2004-10-29

    Insect galectins are associated with embryonic development or immunity against pathogens. Here, we show that they can be exploited by parasites for survival in their insect hosts. PpGalec, a tandem repeat galectin expressed in the midgut of the sandfly Phlebotomus papatasi, is used by Leishmania major as a receptor for mediating specific binding to the insect midgut, an event crucial for parasite survival, and accounts for species-specific vector competence for the most widely distributed form of cutaneous leishmaniasis in the Old World. In addition, these studies demonstrate the feasibility of using midgut receptors for parasite ligands as target antigens for transmission-blocking vaccines. PMID:15543683

  5. Naturally occurring entomopathogenic fungi infecting stored grain insect species in Punjab, Pakistan.

    PubMed

    Wakil, Waqas; Usman Ghazanfar, Muhammad; Yasin, Muhammad

    2014-01-01

    The occurrence of entomopathogenic fungi isolated from stored grain insect pests sampled from various geographical regions of Punjab, Pakistan, was investigated. In total, 25,720 insects from six different species were evaluated, and 195 isolates from 24 different fungal species were recovered. These included the Ascomycetes Beauveria bassiana sensu lato (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae), Metarhizium anisopliae sensu lato (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae), Purpureocillium lilacinum (Thorn) Samson (Hypocreales: Ophiocordycipitaceae), and Lecanicillium attenuatum (Zare and W. Gams) (Hypocreales: Clavicipitaceae). The cadavers of red flour beetle Tribolium castaneum (Herbst.) (Coleoptera: Tenebrionidae) were significantly infected with the fungi followed by rice weevil Sitophilus oryzae (L.) (Coleoptera: Curculionidae), lesser grain borer Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), rusty grain beetle Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae), and cowpea weevil Callosobruchus maculatus (F.) (Coleoptera: Bruchidae); however, the least were recovered from khapra beetle Trogoderma granarium (Everts) (Coleoptera: Dermestidae). The geographical attributes (altitude, longitude, and latitude) greatly influenced the occurrence of entomopathogenic fungi with highest number of isolates found from >400 (m) altitude, 33°-34' N latitude, and 73°-74' E longitude. The findings of the current surveys clearly indicated that the entomopathogenic fungi are widely distributed in the insect cadavers, which may later be used in successful Integrated Pest Management programs. PMID:25480970

  6. Proteomics of survival structures of fungal pathogens.

    PubMed

    Loginov, Dmitry; Šebela, Marek

    2016-09-25

    Fungal pathogens are causal agents of numerous human, animal, and plant diseases. They employ various infection modes to overcome host defense systems. Infection mechanisms of different fungi have been subjected to many comprehensive studies. These investigations have been facilitated by the development of various '-omics' techniques, and proteomics has one of the leading roles in this regard. Fungal conidia and sclerotia could be considered the most important structures for pathogenesis as their germination is one of the first steps towards a host infection. They represent interesting objects for proteomic studies because of the presence of unique proteins with unexplored biotechnological potential required for pathogen viability, development and the subsequent host infection. Proteomic peculiarities of survival structures of different fungi, including those of biotechnological significance (e.g., Asperillus fumigatus, A. nidulans, Metarhizium anisopliae), in a dormant state, as well as changes in the protein production during early stages of fungal development are the subjects of the present review. We focused on biological aspects of proteomic studies of fungal survival structures rather than on an evaluation of proteomic approaches. For that reason, proteins that have been identified in this context are discussed from the point of view of their involvement in different biological processes and possible functions assigned to them. This is the first review paper summarizing recent advances in proteomics of fungal survival structures. PMID:26777984

  7. Genomic Basis of Plant Pathogen Suppression by Biocontrol Pseudomonas Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various plant commensal bacterial species, which naturally colonize the plant rhizosphere, are able to suppress fungal, bacterial, viral and even insect plant pathogens. These biocontrol activities are elicited primarily through the production of secreted exoenzymes and secondary metabolites that ma...

  8. Beneficial Insects and Insect Pollinators on Milkweed in South Georgia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect pollinators are essential for the reproduction of more than two-thirds of the world’s crops, and beneficial insects play an important role in managing pest insects in agricultural farmscapes. These insects depend on nectar for their survival in these farmscapes. The flowers of tropical milkwe...

  9. BIOASSAY PROTOCOL FOR LETHAL AND SUBLETHAL EFFECTS OF FUNGAL PATHOGENS ON CHRYSOPERLA CARNEA

    EPA Science Inventory

    This practice describes procedures for evaluating the lethal and sub-lethal effects of exposure to fungal pathogens on larvae and adults of the predatory insect Chrysoperla carnea (Stephens). his practice was developed and tested with the fungal insect pathogen Beauveria bassiana...

  10. Damage signals in the insect immune response

    PubMed Central

    Krautz, Robert; Arefin, Badrul; Theopold, Ulrich

    2014-01-01

    Insects and mammals share an ancient innate immune system comprising both humoral and cellular responses. The insect immune system consists of the fat body, which secretes effector molecules into the hemolymph and several classes of hemocytes, which reside in the hemolymph and of protective border epithelia. Key features of wound- and immune responses are shared between insect and mammalian immune systems including the mode of activation by commonly shared microbial (non-self) patterns and the recognition of these patterns by dedicated receptors. It is unclear how metazoan parasites in insects, which lack these shared motifs, are recognized. Research in recent years has demonstrated that during entry into the insect host, many eukaryotic pathogens leave traces that alert potential hosts of the damage they have afflicted. In accordance with terminology used in the mammalian immune systems, these signals have been dubbed danger- or damage-associated signals. Damage signals are necessary byproducts generated during entering hosts either by mechanical or proteolytic damage. Here, we briefly review the current stage of knowledge on how wound closure and wound healing during mechanical damage is regulated and how damage-related signals contribute to these processes. We also discuss how sensors of proteolytic activity induce insect innate immune responses. Strikingly damage-associated signals are also released from cells that have aberrant growth, including tumor cells. These signals may induce apoptosis in the damaged cells, the recruitment of immune cells to the aberrant tissue and even activate humoral responses. Thus, this ensures the removal of aberrant cells and compensatory proliferation to replace lost tissue. Several of these pathways may have been co-opted from wound healing and developmental processes. PMID:25071815

  11. Insects and climate change

    SciTech Connect

    Elias, S.A. )

    1991-09-01

    In this article the author describes some of the significant late glacial and Holocene changes that occurred in the Rocky Mountains, including the regional extirpation of certain beetle species. The fossil data presented here summarize what is known about regional insect responses to climate change in terms of species stability and geographic distribution. To minimize potential problems of species interactions (i.e., insect-host plant relationships, host-parasite relationships, and other interactions that tie a particular insect species' distribution to that of another organism), only predators and scavengers are discussed. These insects respond most rapidly to environmental changes, because for the most part they are not tied to any particular type of vegetation.

  12. Insect hemolymph clotting.

    PubMed

    Dushay, Mitchell S

    2009-08-01

    The clot's appearance in different large-bodied insects has been described, but until recently, little was known about any insect clot's molecular makeup, and few experiments could directly test its function. Techniques have been developed in Drosophila (fruit fly) larvae to identify clotting factors that can then be tested for effects on hemostasis, healing, and immunity. This has revealed unanticipated complexity in the hemostatic mechanisms in these larvae. While the clot's molecular structure is not yet fully understood, progress is being made, and the loss of clotting factors has been shown to cause subtle immune defects. The few similarities between coagulation in different insect species and life stages, and the current state of knowledge about coagulation in insects are discussed. PMID:19418022

  13. Feeding the insect industry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article reports the use of insect colloidal artificial diets suitable for the rearing of economically important arthropods, such as Lygus lineolaris, Lygus hesperus, Coleomegilla maculata, and Phytoseiulus persimilis The different diets contain key nutrients such as proteins, carbohydrates, vit...

  14. Important Insect Pests of Fruit - Important Insect Pests of Nuts - Field Crop Insect Pests - Insect Pests of Vegetable Crops.

    ERIC Educational Resources Information Center

    Gesell, Stanley G.; And Others

    This document consists of four agriculture extension service publications from Pennsylvania State University. The titles are: (1) Important Insect Pests of Fruit; (2) Important Insect Pests of Nuts; (3) Field Crop Insect Pests; and (4) Insect Pests of Vegetable Crops. The first publication gives the hosts, injury, and description of 22 insect…

  15. Evolution of the Insects

    NASA Astrophysics Data System (ADS)

    Grimaldi, David; Engel, Michael S.

    2005-05-01

    This book chronicles the complete evolutionary history of insects--their living diversity and relationships as well as 400 million years of fossils. Introductory sections cover the living species diversity of insects, methods of reconstructing evolutionary relationships, basic insect structure, and the diverse modes of insect fossilization and major fossil deposits. Major sections then explore the relationships and evolution of each order of hexapods. The volume also chronicles major episodes in the evolutionary history of insects from their modest beginnings in the Devonian and the origin of wings hundreds of millions of years before pterosaurs and birds to the impact of mass extinctions and the explosive radiation of angiosperms on insects, and how they evolved into the most complex societies in nature. Whereas other volumes focus on either living species or fossils, this is the first comprehensive synthesis of all aspects of insect evolution. Illustrated with 955 photo- and electron- micrographs, drawings, diagrams, and field photos, many in full color and virtually all of them original, this reference will appeal to anyone engaged with insect diversity--professional entomologists and students, insect and fossil collectors, and naturalists. David Grimaldi and Michael S. Engel have collectively published over 200 scientific articles and monographs on the relationships and fossil record of insects, including 10 articles in the journals Science, Nature, and Proceedings of the National Academy of Sciences. David Grimaldi is curator in the Division of Invertebrate Zoology, American Museum of Natural History and adjunct professor at Cornell University, Columbia University, and the City University of New York. David Grimaldi has traveled in 40 countries on 6 continents, collecting and studying recent species of insects and conducting fossil excavations. He is the author of Amber: Window to the Past (Abrams, 2003). Michael S. Engel is an assistant professor in the

  16. Exploring Insect Vision

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2005-01-01

    A fly is buzzing around in the kitchen. You sneak up on it with a flyswatter, but just as you get close to it, it flies away. What makes flies and other insects so good at escaping from danger? The fact that insects have eyesight that can easily detect moving objects is one of the things that help them survive. In this month's Science Shorts,…

  17. Infrared absorption characteristics of Culicoides sonorensis in relation to insect age

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biting midges can transmit diseases that significantly impact livestock in many parts of the world. The age structure of an insect vector population determines its likelihood of transmitting pathogens because the older insects are more likely to be infected than younger ones. Understanding the insec...

  18. Insect--plant adaptations.

    PubMed

    Southwood, T R

    1984-01-01

    The adaptation of insects to plants probably commenced in the early Permian period, though most current associations will be more recent. A major burst of adaptation must have followed the rise of the Angiosperms in the Cretaceous period, though some particular associations are as recent as this century. Living plants form a large proportion of the potential food in most habitats, though insects have had to overcome certain general hurdles to live and feed on them. Insects affect the reproduction and survival of plants, and thus the diversity of plant secondary chemicals may have evolved as a response. Where an insect species has a significant effect on a plant species that is its only host, coevolution may be envisaged. A spectacular example is provided by Heliconius butterflies and passion flower vines, studied by L.E. Gilbert and others. But such cases may be likened to 'vortices in the evolutionary stream': most plant species are influenced by a range of phytophagous insects so that selection will be for general defences--a situation termed diffuse coevolution. Evidence is presented on recent host-plant shifts to illustrate both the restrictions and the flexibility in current insect-plant associations. PMID:6559112

  19. Insect antiviral innate immunity: pathways, effectors, and connections.

    PubMed

    Kingsolver, Megan B; Huang, Zhijing; Hardy, Richard W

    2013-12-13

    Insects are infected by a wide array of viruses some of which are insect restricted and pathogenic, and some of which are transmitted by biting insects to vertebrates. The medical and economic importance of these viruses heightens the need to understand the interaction between the infecting pathogen and the insect immune system in order to develop transmission interventions. The interaction of the virus with the insect host innate immune system plays a critical role in the outcome of infection. The major mechanism of antiviral defense is the small, interfering RNA pathway that responds through the detection of virus-derived double-stranded RNA to suppress virus replication. However, other innate antimicrobial pathways such as Imd, Toll, and Jak-STAT and the autophagy pathway have also been shown to play important roles in antiviral immunity. In this review, we provide an overview of the current understanding of the main insect antiviral pathways and examine recent findings that further our understanding of the roles of these pathways in facilitating a systemic and specific response to infecting viruses. PMID:24120681

  20. Metacridamides A and B, macrocycles from conidia of the entomopathogenic fungus Metarhizium acridum

    PubMed Central

    Krasnoff, Stuart B.; Englich, Ulrich; Miller, Paula G.; Shuler, Michael L.; Glahn, Raymond P.; Donzelli, Bruno G. G.; Gibson, Donna M.

    2012-01-01

    Metarhizium acridum, an entomopathogenic fungus, has been commercialized and used successfully for biocontrol of grasshopper pests in Africa and Australia. Its conidia produce two novel 17-membered macrocycles, metacridamides A (1) and B (2), which consist of a Phe unit condensed with a nonaketide. Planar structures were elucidated by a combination of mass spectrometric and NMR techniques. Following hydrolysis of 1, chiral amino acid analysis assigned the L-configuration to the Phe unit. A crystal structure established the absolute configuration of the eight remaining stereogenic centers in 1. Metacridamide A (1) showed cytotoxicity to three cancer lines with IC50s of 6.2, 11.0, and 10.8 µM against Caco-2 (epithelial colorectal adenocarcinoma), MCF-7 (breast cancer), and HepG2/C3A (hepatoma) cell lines, respectively. In addition, metacridamide B (2) had an IC50 of 18.2 µM against HepG2/C3A, although it was inactive at 100 µM against Caco-2 and MCF-7. Neither analogue showed antimicrobial, phytotoxic, or insecticidal activity. PMID:22292922

  1. Effect of temperature on vegetative growth among isolates of Metarhizium anisopliae and M. flavoviride.

    PubMed

    Ouedraogo, A; Fargues, J; Goettel, M S; Lomer, C J

    1997-01-01

    Effects of temperature on vegetative growth on a semi-synthetic medium of 22 isolates of Metarhizium anisopliae and 14 isolates of M. flavoviride were determined. The majority of isolates of both species grew between 11 and 32 degrees C; several isolates grew at 8 and 37 degrees C. None of the isolates grew at 40 degrees C. Relative growth rate, calculated from the maximum growth rate for each isolate, was significantly affected by temperature and isolate, with significant isolate * temperature interactions. The maximum absolute growth rates among the isolates ranged from 2.5 mm to 5.9 mm/day. Optimal temperatures were generally between 25 and 32 degrees C with several isolates exhibiting optimal growth at temperatures as high as 32 degrees C. Overall, relative growth rates were greater in isolates of M. anisopliae than M. flavoviride at temperatures of 25 degrees C or lower; conversely mean relative growth rates were greater in M. flavoviride than M. anisopliae at temperatures higher than 25 degrees C. However, the two most cold tolerant isolates at 8 degrees C were M. flavoviride and the three most heat tolerant at 35 degrees C were M. anisopliae. Since temperature growth responses varied considerably between isolates, strain selection according to thermal tolerance may be warranted when choosing a strain for development as a microbial control agent. PMID:16284806

  2. Biological control of Ixodes ricinus larvae and nymphs with Metarhizium anisopliae blastospores.

    PubMed

    Wassermann, Marion; Selzer, Philipp; Steidle, Johannes L M; Mackenstedt, Ute

    2016-07-01

    The entomopathogenic fungus Metarhizium anisopliae is used as a biological pest control agent against various arthropod species, including ticks. However, the efficacy depends on tick species, tick stage and fungus strain. We studied the effect of M. anisopliae on engorged larvae and nymphs of Ixodes ricinus, the most abundant tick species in Europe, under laboratory and semi-field conditions. A significant reduction of engorged larvae and nymphs could be shown under laboratory as well as under semi-field conditions. Only 3.5% of the larvae treated in the lab and only 18.5% kept under semi-field conditions were able to develop into nymphs compared to the recovered nymphs of the control groups, which were regarded as 100%. Only 7.1% of nymphs were recovered as adult ticks after fungal treatment under semi-field conditions compared to the control (100%). The efficacy of blastospores of M. anisopliae against engorged larvae and nymphs of I. ricinus under semi-field conditions was demonstrated in this study, showing their high potential as a biological control agent of ticks. Further studies will have to investigate the effect of this agent against other stages of I. ricinus as well as other tick species before its value as a biological control agent against ticks can be fully assessed. PMID:27005430

  3. Mmc, a gene involved in microcycle conidiation of the entomopathogenic fungus Metarhizium anisopliae.

    PubMed

    Liu, Jing; Cao, Yueqing; Xia, Yuxian

    2010-10-01

    Microcycle conidiation is a survival mechanism for some fungi encountering unfavorable conditions, in which asexual spores germinate secondary spores directly without formation of mycelium. Here, we isolated a microcycle conidiation associated gene, Mmc, from Metarhizium anisopliae and obtained its full length of cDNA and DNA sequence. To clarify its roles in conidiation, we constructed an Mmc RNA interference (RNAi) vector with dual promoter system to knockdown Mmc transcript level, and then analyzed RNAi mutant phenotypes. On microcycle conidiation medium, the RNAi mutant performed normal conidiation instead of microcycle conidiation with significantly reduced growth speed and conidia yield of 5.29-fold and 3.18-fold lower, respectively, than that of the wild-type. Meanwhile, on normal conidiation medium, no significant difference was found in conidiation speed and total yield between the wild-type and RNAi mutant. These data demonstrated that the Mmc gene regulated microcycle conidiation but did not affect normal conidiation. In addition, results of heat treatment, UV-B radiation and bioassays of RNAi mutant indicated that Mmc was also involved in heat resistance but irrelevant to UV-B tolerance and virulence of M. anisopliae. This study helped understanding the regulation of sporulation of the entomopathogenic fungus M. anisopliae. PMID:20546749

  4. Optimization of different process variables for the production of an indolizidine alkaloid, swainsonine from Metarhizium anisopliae.

    PubMed

    Singh, Digar; Kaur, Gurvinder

    2012-10-01

    Swainsonine is a polyhydroxylated indolizidine alkaloid having anticancer, antimetastatic, antiproliferative and immunomodulatory activities and also potential therapeutic applications against AIDS. In the present study, ten isolates of M. anisopliae were screened and enzyme assayed for the production of swainsonine in different media (Complex oatmeal, Czapekdox media with and without lysine (8% w/v) and Sabouraud dextrose broth (SDB)). Among these strains, ARSEF 1724 (UM8) was found to produce highest amount of swainsonine (1.34 μg/l) after 72 h of incubation under shake flask conditions at 180 rpm and 28 °C in complex oatmeal media. In order to maximize the yield of swainsonine the media composition including macro and micronutrients were optimized. The process variables including the chemical factors like carbon sources, nitrogen sources of both organic and inorganic nature and pH with constant inoculum size (1 × 10(8) spores/ml) were screened using classical one-factor-at-a-time (OFAT) approach to find their optimum levels. The present study shows that the nutrient requirement is specific for each strain of Metarhizium. Oatmeal extract (6%) was found to be the best supporting media along with nitrogen source, glucose (2%) as best carbon source and pH (~5) as the best for swainsonine production. PMID:22144370

  5. Beauveria bassiana and Metarhizium anisopliae endophytically colonize cassava roots following soil drench inoculation

    PubMed Central

    Greenfield, Melinda; Gómez-Jiménez, María I.; Ortiz, Viviana; Vega, Fernando E.; Kramer, Matthew; Parsa, Soroush

    2016-01-01

    We investigated the fungal entomopathogens Beauveria bassiana and Metarhizium anisopliae to determine if endophytic colonization could be achieved in cassava. An inoculation method based on drenching the soil around cassava stem cuttings using conidial suspensions resulted in endophytic colonization of cassava roots by both entomopathogens, though neither was found in the leaves or stems of the treated cassava plants. Both fungal entomopathogens were detected more often in the proximal end of the root than in the distal end. Colonization levels of B. bassiana were higher when plants were sampled at 7–9 days post-inoculation (84%) compared to 47–49 days post-inoculation (40%). In contrast, the colonization levels of M. anisopliae remained constant from 7–9 days post-inoculation (80%) to 47–49 days post-inoculation (80%), which suggests M. anisopliae is better able to persist in the soil, or as an endophyte in cassava roots over time. Differences in colonization success and plant growth were found among the fungal entomopathogen treatments. PMID:27103778

  6. Insect Repellents: Modulators of mosquito odorant receptor activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquitoes vector numerous pathogens that cause diseases including malaria, yellow fever, dengue fever and chikungunya. DEET, IR3535, Picaridin and 2-undecanone are insect repellents that are used to prevent interactions between humans and a broad array of disease vectors including mosquitoes. While...

  7. Chapter 4: Baculoviruses and other occluded insect viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Baculoviruses are among the most thoroughly studied insect pathogens. Members of Baculoviridae possess a large, circular double-stranded DNA genome contained within the enveloped nucleoprotein core of a rod-shaped virion. Baculovirus replication is distinguished by the production of two different ...

  8. Insect bite reactions.

    PubMed

    Singh, Sanjay; Mann, Baldeep Kaur

    2013-01-01

    Insects are a class of living creatures within the arthropods. Insect bite reactions are commonly seen in clinical practice. The present review touches upon the medically important insects and their places in the classification, the sparse literature on the epidemiology of insect bites in India, and different variables influencing the susceptibility of an individual to insect bites. Clinical features of mosquito bites, hypersensitivity to mosquito bites Epstein-Barr virus NK (HMB-EBV-NK) disease, eruptive pseudoangiomatosis, Skeeter syndrome, papular pruritic eruption of HIV/AIDS, and clinical features produced by bed bugs, Mexican chicken bugs, assassin bugs, kissing bugs, fleas, black flies, Blandford flies, louse flies, tsetse flies, midges, and thrips are discussed. Brief account is presented of the immunogenic components of mosquito and bed bug saliva. Papular urticaria is discussed including its epidemiology, the 5 stages of skin reaction, the SCRATCH principle as an aid in diagnosis, and the recent evidence supporting participation of types I, III, and IV hypersensitivity reactions in its causation is summarized. Recent developments in the treatment of pediculosis capitis including spinosad 0.9% suspension, benzyl alcohol 5% lotion, dimethicone 4% lotion, isopropyl myristate 50% rinse, and other suffocants are discussed within the context of evidence derived from randomized controlled trials and key findings of a recent systematic review. We also touch upon a non-chemical treatment of head lice and the ineffectiveness of egg-loosening products. Knockdown resistance (kdr) as the genetic mechanism making the lice nerves insensitive to permethrin is discussed along with the surprising contrary clinical evidence from Europe about efficacy of permethrin in children with head lice carrying kdr-like gene. The review also presents a brief account of insects as vectors of diseases and ends with discussion of prevention of insect bites and some serious adverse effects

  9. Enterococci in Insects

    PubMed Central

    Martin, Jonathan D.; Mundt, J. Orvin

    1972-01-01

    Enterococci were obtained from 213 of 403 insects cultured during a 14-month period, in numbers from 103 to 3 × 107/g of insect. Insects were taken only from nonurban, wild, and cultivated fields and woods. In species of insects carrying them, enterococci were not always present in every individual cultured, and often more than one species of enterococcus occurred within a species. Enterococci were obtained from certain insects taken in the field during the dormant season, suggesting their role as overwintering agents. They were generally present in species feeding on nectar, succulent plant parts, and on and ir forest litter, but not from insects feeding on less succulent leaves and stems. Streptococcus faecalis was recovered from 32%, Streptococcus faecium from 22.4%, and Streptococcus faecium var. casseliflavus from 43.5% of members of the 37 taxa of insects. S. faecalis and S. faecium var. casseliflavus exhibit a high percent of conformity to the properties published for them. The heterogeneity in properties of S. faecium is similar to that found for the species taken from plants. Many fail to grow in broth at 45 C or in broth containing 6.5% NaCl; 50% of the cultures ferment both melezitose and melibiose, and a few ferment neither sugar. The remainder ferment melibiose only. Failure to reduce methylene blue in milk by S. faecalis and S. faecium is correlated with the inability to ferment lactose. More than 93% of the cultures of S. faecalis digest casein in milk from the top downward, following the production of a soft, flowing curd. Because this property is not characteristic of S. faecalis taken from humans, the reaction in litmus milk is suggested as a means of differentiation between cultures of remote and innocent origin in nature and recent, human pollution. PMID:4628796

  10. Evaluation of insect associated and plant growth promoting fungi in the control of cabbage root flies.

    PubMed

    Razinger, Jaka; Lutz, Matthias; Schroers, Hans-Josef; Urek, Gregor; Grunder, Jürg

    2014-08-01

    Delia radicum L. or cabbage maggot is an important pest for Brassicaceous crops. There are currently no registered chemical control agents for its control in Slovenia. Fungal control agents for cabbage maggot were therefore sought among nine rhizosphere-compatible and plant growth-promoting, soil-adapted, and entomopathogenic species to cabbage maggots and were assayed in in vitro and soil laboratory bioassays. In the in vitro tests, the conidial suspensions were applied directly to cabbage maggot eggs. The soil tests mimicked pathways of natural exposure of various insect life stages to the fungal strains. Conidial concentrations used in soil tests were comparable to economic rates for in-furrow application. The following fungi were tested: Trichoderma atroviride P. Karst. (2 isolates), Trichoderma koningiopsis Samuels, C. Suárez & H.C. Evans (1), Trichoderma gamsii Samuels & Druzhin. (3), Beauveria brongniartii (Saccardo) Petch (1), Beauveria bassiana (Balsamo-Crivelli) Vuillemin (2), Metarhizium robertsii J.F. Bisch., Rehner & Humber (1), Metarhizium anisopliae (Metschn.) Sorokin (4), Purpureocillium lilacinum (Thom) Luangsa-ard, Houbraken, Hywel-Jones & Samson (2), and Clonostachys solani f. nigrovirens (J.F.H. Beyma) Schroers (2). Abbott's corrected mortality in the in vitro tests ranged from 0.0 +/- 18.9 to 47.6 +/- 9.0% and in the soil test from 2.4 +/- 13.0 to 68.2 +/- 21.5%. Seven isolates (B. bassiana [isolate 1174], C. solani [1828], M. anisopliae [1154 and 1868], T. atroviride [1872], T. koningiopsis [1874], and T. gamsii [1876]) caused significant cabbage maggot mortality in either in vitro or soil tests. The importance of fungal ecology as a criterion during the screening of potential biological control agents is discussed. PMID:25195421

  11. Insect natural products and processes: new treatments for human disease.

    PubMed

    Ratcliffe, Norman A; Mello, Cicero B; Garcia, Eloi S; Butt, Tariq M; Azambuja, Patricia

    2011-10-01

    In this overview, some of the more significant recent developments in bioengineering natural products from insects with use or potential use in modern medicine are described, as well as in utilisation of insects as models for studying essential mammalian processes such as immune responses to pathogens. To date, insects have been relatively neglected as sources of modern drugs although they have provided valuable natural products, including honey and silk, for at least 4-7000 years, and have featured in folklore medicine for thousands of years. Particular examples of Insect Folk Medicines will briefly be described which have subsequently led through the application of molecular and bioengineering techniques to the development of bioactive compounds with great potential as pharmaceuticals in modern medicine. Insect products reviewed have been derived from honey, venom, silk, cantharidin, whole insect extracts, maggots, and blood-sucking arthropods. Drug activities detected include powerful antimicrobials against antibiotic-resistant bacteria and HIV, as well as anti-cancer, anti-angiogenesis and anti-coagulant factors and wound healing agents. Finally, the many problems in developing these insect products as human therapeutic drugs are considered and the possible solutions emerging to these problems are described. PMID:21658450

  12. Behavioral Immunity in Insects

    PubMed Central

    de Roode, Jacobus C.; Lefèvre, Thierry

    2012-01-01

    Parasites can dramatically reduce the fitness of their hosts, and natural selection should favor defense mechanisms that can protect hosts against disease. Much work has focused on understanding genetic and physiological immunity against parasites, but hosts can also use behaviors to avoid infection, reduce parasite growth or alleviate disease symptoms. It is increasingly recognized that such behaviors are common in insects, providing strong protection against parasites and parasitoids. We review the current evidence for behavioral immunity in insects, present a framework for investigating such behavior, and emphasize that behavioral immunity may act through indirect rather than direct fitness benefits. We also discuss the implications for host-parasite co-evolution, local adaptation, and the evolution of non-behavioral physiological immune systems. Finally, we argue that the study of behavioral immunity in insects has much to offer for investigations in vertebrates, in which this topic has traditionally been studied. PMID:26466629

  13. Maize Kauralexins: inducible diterpenoid phytoalexins protect against fungal pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytoalexins constitute a broad category of pathogen and insect-inducible biochemicals that locally protect plant tissues. In rice, a complex array of inducible diterpenoid phytoalexins constitute an important component of the plants anti-pathogen defenses. In contrast, despite the demonstration of ...

  14. Insect Repellents: Protect Your Child from Insect Bites

    MedlinePlus

    ... Español Text Size Email Print Share Choosing an Insect Repellent for Your Child Page Content Article Body Mosquitoes , ... sunscreen needs to be reapplied often. Reactions to Insect Repellents If you suspect that your child is having ...

  15. Rapid evolution of immune proteins in social insects.

    PubMed

    Viljakainen, Lumi; Evans, Jay D; Hasselmann, Martin; Rueppell, Olav; Tingek, Salim; Pamilo, Pekka

    2009-08-01

    The existence of behavioral traits connected to defense against pathogens manifests the importance of pathogens in the evolution of social insects. However, very little is known about how pathogen pressure has affected the molecular evolution of genes involved in their innate immune system. We have studied the sequence evolution of several immune genes in ants and honeybees. The results show high rates of evolution in both ants and honeybees as measured by the ratio of amino acid changes to silent nucleotide changes, the ratio being clearly higher than in Drosophila immune genes or in nonimmunity genes of bees. This conforms to our expectations based on high pathogen pressure in social insects. The codon-based likelihood method found clear evidence of positive selection only in one ant gene, even though positive selection has earlier been found in both ant and termite immune genes. There is now indication that selection on the amino acid composition of the immune-related genes has been an important part in the fight against pathogens by social insects. However, we cannot distinguish in all the cases whether the high observed d(N)/d(S) ratio results from positive selection within a restricted part of the studied genes or from relaxation of purifying selection associated with effective measures of behaviorally based colony-level defenses. PMID:19387012

  16. Cognition in insects

    PubMed Central

    Webb, Barbara

    2012-01-01

    A traditional view of cognition is that it involves an internal process that represents, tracks or predicts an external process. This is not a general characteristic of all complex neural processing or feedback control, but rather implies specific forms of processing giving rise to specific behavioural capabilities. In this paper, I will review the evidence for such capabilities in insect navigation and learning. Do insects know where they are, or do they only know what to do? Do they learn what stimuli mean, or do they only learn how to behave? PMID:22927570

  17. Development of a user-friendly delivery method for the fungus Metarhizium anisopliac to control the ectoparasitic mite Varroa destructor in honey bee, Apis mellifera, colonies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A user-friendly method to deliver Metarhizium spores to honey bee colonies for control of Varroa mites was developed and tested. Patty blend formulations protected the fungal spores at brood nest temperatures and served as an improved delivery system of the fungus to bee hives. Field trials conducte...

  18. Simulated aerial sprays for field cage evaluation of Beauveria bassiana and Metarhizium brunneum (Ascomycetes: Hypocreales) against Anabrus simplex (Orthoptera: Tettigoniidae) in Montana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field efficacy of the entomopathogenic Ascomycete Beauveria bassiana strain GHA and Metarhizium brunneum strain F52 was evaluated against nymphs of the Mormon cricket, Anabrus simplex. Fungi were applied with a new apparatus that allows simulated aerial sprays to 0.1m2 areas in the field. The Mormon...

  19. Virulence of Beauveria bassiana and Metarhizium anisopliae (Ascomycota: Hypocreales) commercial strains against adult Xylosandrus germanus (Coleoptera: Scolytidae) and impact on brood

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ambrosia beetle Xylosandrus germanus is an invasive pest with a wide host range and is a serious pest of orchards and nurseries in the eastern US. In this study we evaluated the potential of entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae as control agents against this beet...

  20. Development of pilot-scale fermentation and stabilization processes for the production of microsclerotia of the entomopathogenic fungus Metarhizium brunneun strain F52

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using 100L stirred-tank bioreactors, we evaluated the effect of fermentation parameters and drying protocols on the production and stabilization of microsclerotia (MS) of the entomopathogenic fungus Metarhizium brunneum (formerly M. anisopliae F52). Results showed that stirred-tank bioreactors can ...

  1. Persistence of Metarhizium Anisopliae Incorporated into Soilless Potting Media for Control of the Black Vine Weevil, Otiorhynchus Sulcatus in Container-Grown Ornamentals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The black vine weevil (BVW), Otiorhynchus sulcatus (F.) is a serious pest of nursery crops, particularly in the Pacific Northwest. The fungus, Metarhizium anisopliae (F52), has recently been registered by the US Environmental Protection Agency for BVW control. The objective of this study was to de...

  2. Inhibition of the entomopathogenic fungus Metarhizium anisopliae in vitro by the bed bug defensive secretions (E)-2-hexenal and (E)-2-octenal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The two major aldehydes (E)-2-hexenal and (E)-2-octenal emitted as defensive secretions by bed bugs Cimex lectularius L. (Hemiptera: Cimicidae), inhibit the in vitro growth of Metarhizium anisopliae (Metsch.) Sokorin (Hypocreales: Clavicipitaceae). These chemicals inhibit fungal growth by direct con...

  3. Impact of Metarhizium brunneum (Hypocreales: Clavicipitaceae) on pre-imaginal Rhagoletis indifferens (Diptera: Tephritidae) within and on the surface of orchard soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When last instar laboratory-reared Rhagoletis indifferens (Cherry Fruit Fly) were allowed to pupate within non-sterile orchard soil containing incorporated Metarhizium brunneum isolate F52 conidia, a dose-related proportion died from developmental abnormalities and mycosis. Similarly, when prepupal ...

  4. Evaluation of Metarhizium anisopliae strain F52 (Hypocreales: Clavicipitaceae) for control of Ixodes scapularis (Acari: Ixodidae).

    PubMed

    Bharadwaj, Anuja; Stafford, Kirby C

    2010-09-01

    Field efficacy of an emulsifiable concentrate formulation of the entomopathogenic fungus Metarhizium anisopliae strain F52 for the control of Ixodes scapularis nymphs was evaluated at residential sites in northwestern Connecticut in 2007. Two spray applications with two rates, 3.2 x 10(5) and 1.3 x 10(6) spores/cm2, were made: the first on 8-9 May, 2-3 wk before nymphal activity, and the second on 29 June or 2 July when ticks were active. There was no significant difference in nymphal abundance between the three treatment groups (P = 0.490) after the first application, indicating that preseason or early applications are not effective, despite a bioasaay with yellow mealworms that showed spores in the treated areas was infective for at least 1 mo postapplication. By contrast, there was a significant difference in the number of nymphs collected between the treatments and control 3 wk (F = 16.928, df = 2, P < 0.001) and 5 wk (F = 6.627, df = 2, P = 0.002) after the second application. During the 3 wk after the second application, 87.1 and 96.1% fewer ticks were collected from lower and higher rate-treated sites, respectively, and after 5 wk, tick reductions were 53.2 and 73.8%, respectively. Over one- third (36.4% of 173) of the nymphs collected from the treated sites developed mycosis from M. anisopliae. The application of M. anisopliae strain F52 could provide another tool for the integrated approach to managing ticks in the residential landscape. PMID:20939382

  5. Inhibition of hepatitis B virus gene expression & replication by crude destruxins from Metarhizium anisopliae var. dcjhyium

    PubMed Central

    Dong, Cong; Yu, Jiuru; Zhu, Ying; Dong, Changjin

    2013-01-01

    Background & objectives: Destruxin A, destruxin B and destruxin E isolated from entomopathogenic fungus Metarhizium anisopliae showed a strong suppressive effect on the replication of hepatitis B virus (HBV) in human hepatoma cells. In this study, the anti-HBV effects of the crude destruxins extracted from M. anisopliae var. dcjhyium were detected both in vitro and in vivo. Methods: HepG2.2.15 cells were cultured to observe the inhibitory effects of the crude destruxins on the gene expression and replication of HBV by radioimmunoassay detection and real-time quantitative PCR. In vivo, duck HBV (DHBV)-infected ducks were treated with the crude destruxins at 2.0, 4.0, 6.0 μg/kg once a day for 15 days, DHBV DNA was examined by real-time quantitative PCR. Results: The crude destruxins suppressed the replication of HBV-DNA and the production of HBsAg and HBeAg with IC50 of about 1.2 and 1.4 μg/ml. Transcript of viral mRNA was significantly suppressed by the crude destruxins in HepG2.2.15 cells. In vivo, the duck serum DHBV-DNA levels were markedly reduced in the group of the crude destruxins. Interpretation & conclusions: The crude destruxins inhibited the gene expression and replication of HBV both in vitro and in vivo, and their anti-HBV effect was stronger than that with destruxin B. Our results indicate that the crude destruxins from M.anisopliae var. dcjhyium may be potential antivirus agents. Further studies need to be done to confirm these findings. PMID:24521644

  6. Selection of indigenous isolates of entomopathogenic soil fungus Metarhizium anisopliae under laboratory conditions.

    PubMed

    Skalický, Aleš; Bohatá, Andrea; Šimková, Jana; Osborne, Lance S; Landa, Zdeněk

    2014-07-01

    Eight native isolates of the entomopathogenic fungus Metarhizium anisopliae (Metschnikoff) Sorokin were obtained by monitoring soils cultivated in a conventional manner. These isolates were compared in three areas: (a) conidial germination, (b) radial growth and sporulation and (c) ability of conidia to infect Tenebrio molitor larvae. All bioassays were carried out at constant temperatures of 10, 15, and 20 °C. Conidia of individual isolates demonstrated differences in germination after a 24-h long incubation at all evaluated temperatures. At 20 °C, the germination ranged from 67 to 100 % and at 15 °C from 5.33 to 46.67 %. At 10 °C, no germination was observed after 24 h; nevertheless, it was 8.67-44.67 % after 48 h. In terms of radial growth, the culture diameters and the associated production of spores of all isolates increased with increasing temperature. At 10 °C, sporulation was observed in three isolates while all remaining cultures appeared sterile. Three weeks post-inoculation, conidia of all assessed isolates caused 100 % cumulative mortality of treated larvae of T. molitor at 15 and 20 °C with the exception of isolate 110108 that induced 81.33 % mortality at 15 °C. At 10 °C, larval cumulative mortality ranged from 6.67 to 85.33 % depending on the isolate. Isolates 110108 and 110111 showed significantly slower outset and a much lower rate of infection at all temperatures compared to other tested isolates of M. anisopliae. The bioassays were carried out with the purpose to sort and select indigenous isolates of M. anisopliae useful as biocontrol agents in their original habitat. PMID:24338078

  7. Effects of Metarhizium anisopliae conidia mixed with soil against the eggs of Aedes aegypti.

    PubMed

    Leles, Renan Nunes; D'Alessandro, Walmirton Bezerra; Luz, Christian

    2012-04-01

    The effectiveness of Metarhizium anisopliae IP 46 conidia mixed with soil was tested against Aedes aegypti eggs. Mycelium and new conidia developed first on eggs between 4.8 and 15 days respectively after incubation of fungus-treated soils at 3.3 × 10(3) up to 3.3 × 10(5) conidia/g soil at 25°C and relative humidities close to saturation. After 15-day incubation, 53.3% of the eggs exposed to soil with 3.3 × 10(5) conidia/g showed external development of mycelium and conidia. Fungus-inoculated soils (but not untreated controls) showed some mycelial growth and sporulation apart from the eggs. Some eggs on treated soils hatched; those larvae died and eventually showed fungal development on their bodies. The cumulative relative eclosion of larvae after submersion of treated eggs in water decreased from 52.2% at 3.3 × 10(3) conidia/g to 25.3% at 3.3 × 10(5) conidia/g. These findings clearly showed that A. aegypti eggs can be infected by M. anisopliae when deposited on fungus-contaminated soil. The effectiveness of M. anisopliae against gravid females, larvae, and also eggs of A. aegypti underscored the possible usefulness of this fungus as a mycoinsecticide, whether naturally occurring or artificially applied, in the breeding sites of this mosquito. PMID:21984368

  8. Evaluation of Metarhizium brunneum F52 (Hypocreales: Clavicipitaceae) for Control of Japanese Beetle Larvae in Turfgrass.

    PubMed

    Behle, Robert W; Richmond, Douglas S; Jackson, Mark A; Dunlap, Christopher A

    2015-08-01

    Experimental and commercial preparations of Metarhizium brunneum (Petch) strain F52 were evaluated for control of Japanese beetle, Popillia japonica Newman (Coleoptera: Scarbaeidae), larvae (white grubs) in the laboratory and under field conditions. Experimental preparations consisted of granule and liquid formulations made using in vitro produced microsclerotia, which are intended to produce infective conidial spores after application. These formulations were compared against commercial insecticides (imidacloprid and trichlorfon), and commercial formulations of M. brunneum F52 (Met 52) containing only conidia. Field-collected grubs were susceptible to infection in a dosage-dependent relationship when exposed to potting soil treated with experimental microsclerotia granules in the laboratory. The LC(50) for field-collected larvae was 14.2 mg of granules per cup (∼15 g granules/m(2)). Field plots treated with experimental and commercial formulations of M. brunneum F52 after 10 September (targeting second and third instar grubs) had significantly lower grub densities compared with untreated plots, providing 38.6-69.2% control, which sometimes equaled levels of control with chemical insecticides. Fungal treatments made prior to 21 August provided 14.3-69.3% control, although grub densities resulting from these treatments were often not significantly lower than those in untreated control plots. By comparison, chemical insecticide treatments provide 68-100% grub control, often providing better control when applied earlier in the season. In conclusion, P. japonica larvae are susceptible to infection by M. brunneum, and grub densities were reduced most consistently by fall applications targeting later instars. PMID:26470299

  9. Protecting Yourself from Stinging Insects

    MedlinePlus

    ... at risk of being stung by flying insects (bees, wasps, and hornets) and fire ants. While most ... by several stinging insects, run to get away. (Bees release a chemical when they sting, which attracts ...

  10. Investigation--Insects!

    ERIC Educational Resources Information Center

    Fay, Janice

    2000-01-01

    Presents activities on insects for second grade students. In the first activity, students build a butterfly garden. In the second activity, students observe stimuli reactions with mealworms in the larval stage. Describes the assessment process and discusses the effects of pollution on living things. (YDS)

  11. Fluorescence in insects

    NASA Astrophysics Data System (ADS)

    Welch, Victoria L.; Van Hooijdonk, Eloise; Intrater, Nurit; Vigneron, Jean-Pol

    2012-10-01

    Fluorescent molecules are much in demand for biosensors, solar cells, LEDs and VCSEL diodes, therefore, considerable efforts have been expended in designing and tailoring fluorescence to specific technical applications. However, naturally occurring fluorescence of diverse types has been reported from a wide array of living organisms: most famously, the jellyfish Aequorea victoria, but also in over 100 species of coral and in the cuticle of scorpions, where it is the rule, rather than the exception. Despite the plethora of known insect species, comparatively few quantitative studies have been made of insect fluorescence. Because of the potential applications of natural fluorescence, studies in this field have relevance to both physics and biology. Therefore, in this paper, we review the literature on insect fluorescence, before documenting its occurrence in the longhorn beetles Sternotomis virescens, Sternotomis variabilis var. semi rufescens, Anoplophora elegans and Stellognatha maculata, the tiger beetles Cicindela maritima and Cicindela germanica and the weevil Pachyrrhynchus gemmatus purpureus. Optical features of insect fluorescence, including emitted wavelength, molecular ageing and naturally occurring combinations of fluorescence with bioluminescence and colour-producing structures are discussed.

  12. Insects. Thematic Unit.

    ERIC Educational Resources Information Center

    Gosnell, Kathee

    This book is a captivating whole-language thematic unit about the study of insects, relating it to our understanding of the past and our hopes for using our knowledge in the present to balance the ecosystem in the future. It contains a wide variety of lesson ideas and reproducible pages designed for use with intermediate students. At its core,…

  13. SOCIAL INSECT PHEROMONES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Social insects include the social Hymenoptera (Formicidae, ants; Apidae, bees; Vespidae, wasps) and Isoptera (Termitidae, termites). Social interactions are required for effective food retrieval, brood and queen care, regulation of caste (sexuals/workers), recognition and exclusion of non-nestmates,...

  14. People and Insects.

    ERIC Educational Resources Information Center

    NatureScope, 1985

    1985-01-01

    Provides: (1) background information on how insects affect human lives, both positively and negatively, and on integrated pest management strategies; (2) student activities; and (3) materials (ready-to-copy games, puzzles, coloring pages, worksheets, and/or mazes). Each activity includes an objective, recommended age level(s), subject area(s),…

  15. Insect mass production technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insects provide a very promising alternative for the future production of animal protein. Their nutritional value in conjunction with their food conversion efficiency and low water requirements, make them a more sustainable choice for the production of food and animal origin. However, to realize the...

  16. Recycled Insect Models

    ERIC Educational Resources Information Center

    Rule, Audrey C.; Meyer, Mary Ann

    2007-01-01

    This article presents an engaging activity in which high school students use a dichotomous key to guide the creation and classification of model insects from recycled plastic lids and containers. Besides teaching the use of a dichotomous key and the effect of evolutionary descent upon groupings of organisms, this activity focuses on an…

  17. Dispersal of forest insects

    NASA Technical Reports Server (NTRS)

    Mcmanus, M. L.

    1979-01-01

    Dispersal flights of selected species of forest insects which are associated with periodic outbreaks of pests that occur over large contiguous forested areas are discussed. Gypsy moths, spruce budworms, and forest tent caterpillars were studied for their massive migrations in forested areas. Results indicate that large dispersals into forested areas are due to the females, except in the case of the gypsy moth.

  18. Irradiating insect pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This is a non-technical article focusing on phytosanitary uses of irradiation. In a series of interview questions, I present information on the scope of the invasive species problem and the contribution of international trade in agricultural products to the movement of invasive insects. This is foll...

  19. Corn Insect Pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Historically, the major corn insect pests have been corn rootworms (northern and western), European corn borer, and black cutworm. Bt-corn hybrids are effective against most of these pests. However, Bt-corn hybrids are not effective against corn leaf aphid, corn root aphid, sap beetles, corn rootwor...

  20. Colour constancy in insects.

    PubMed

    Chittka, Lars; Faruq, Samia; Skorupski, Peter; Werner, Annette

    2014-06-01

    Colour constancy is the perceptual phenomenon that the colour of an object appears largely unchanged, even if the spectral composition of the illuminating light changes. Colour constancy has been found in all insect species so far tested. Especially the pollinating insects offer a remarkable opportunity to study the ecological significance of colour constancy since they spend much of their adult lives identifying and choosing between colour targets (flowers) under continuously changing ambient lighting conditions. In bees, whose colour vision is best studied among the insects, the compensation provided by colour constancy is only partial and its efficiency depends on the area of colour space. There is no evidence for complete 'discounting' of the illuminant in bees, and the spectral composition of the light can itself be used as adaptive information. In patchy illumination, bees adjust their spatial foraging to minimise transitions between variously illuminated zones. Modelling allows the quantification of the adaptive benefits of various colour constancy mechanisms in the economy of nature. We also discuss the neural mechanisms and cognitive operations that might underpin colour constancy in insects. PMID:24647930

  1. Internal Boll Rots Associated with Feeding by Hemipterous Insects: A Review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When stink bugs, plant bugs and cotton fleahoppers feed on bolls and buds, the locks within the boll often become discolored or rotted. Such symptoms are usually caused by microbial pathogens introduced by insects. The roles of pathogens have been determined by antiseptically isolating microorgani...

  2. APPLICATION AND EVALUATION OF ENTOMOPATHOGENS FOR MANAGING INSECTS IN STORED PRODUCTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Currently two pathogens, Bacillus thuringiensis and Indianmeal moth granulovirus, are registered for control of stored-product pest insects. Very little field work has been done with other pathogen species, and there is a paucity of methodology guidance for researchers in this area. The chapter fir...

  3. Screening of tropical isolates of Metarhizium anisopliae for virulence to the red palm weevil Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae).

    PubMed

    Sun, Xiaodong; Yan, Wei; Qin, Weiquan; Zhang, Jing; Niu, Xiaoqing; Ma, Guangchang; Li, Fuheng

    2016-01-01

    The red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) is a serious pest of the palm tree in tropical regions of the world. One strain of Metarhizium sp. ZJ-1, isolated from Chinese soils, was evaluated for growth characteristics, and screened for its virulence to R. ferrugineus larvae in laboratory conditions. An approximately 685-bp fragment was amplified by ITS (ITS1-5.8S-ITS2) PCR from strain ZJ-1, further phylogenetic analysis revealed that 93 % similarity to Metarhizium anisopliae. Inoculation of 1 × 10(8) conidia/mL caused 100 % mortality of R. ferrugineus, LT50 levels of ZJ-1 were 1.66 days (1 × 10(8) conidia/mL), indicating that the conidia of strain ZJ-1 were highly virulent. These results suggest that M. anisopliae ZJ-1 has potential as an effective and persistent biological control agent for R. ferrugineus. PMID:27468401

  4. Radar cross section of insects

    NASA Astrophysics Data System (ADS)

    Riley, J. R.

    1985-02-01

    X-band measurements of radar cross section as a function of the angle between insect body axis and the plane of polarization are presented. A finding of particular interest is that in larger insects, maximum cross section occurs when the E-vector is perpendicular to the body axis. A new range of measurements on small insects (aphids, and planthoppers) is also described, and a comprehensive summary of insect cross-section data at X-band is given.

  5. The molecular basis of bacterial-insect symbiosis

    PubMed Central

    Douglas, Angela E.

    2015-01-01

    Insects provide experimentally tractable and cost-effective model systems to investigate the molecular basis of animal-bacterial interactions. Recent research is revealing the central role of the insect innate immune system, especially anti-microbial peptides and reactive oxygen species, in regulating the abundance and composition of the microbiota in various insects, including Drosophila and the mosquitoes Aedes and Anopheles. Interactions between the immune system and microbiota are, however, bidirectional with evidence that members of the resident microbiota can promote immune function, conferring resistance to pathogens and parasites by both activation of immune effectors and production of toxins. Antagonistic and mutualistic interactions among bacteria have also been implicated as determinants of the microbiota composition, including exclusion of pathogens, but the molecular mechanisms are largely unknown. Some bacteria are crucial for insect nutrition, through provisioning of specific nutrients (e.g. B vitamins, essential amino acids) and modulation of the insect nutritional sensing and signaling pathways (e.g. insulin signaling) that regulate nutrient allocation, especially to lipid and other energy reserves. A key challenge for future research is to identify the molecular interaction between specific bacterial effectors and animal receptors, and to determine how these interactions translate into microbiota-dependent signaling, metabolism and immune function in the host. PMID:24735869

  6. Insects as weapons of war, terror, and torture.

    PubMed

    Lockwood, Jeffrey A

    2012-01-01

    For thousands of years insects have been incorporated into human conflict, with the goals of inflicting pain, destroying food, and transmitting pathogens. Early methods used insects as "found" weapons, functioning as tactical arms (e.g., hurled nests) or in strategic habitats (e.g., mosquito-infested swamps). In the twentieth century the relationship between insects and disease was exploited; vectors were mass-produced to efficiently deliver pathogens to an enemy. The two most sophisticated programs were those of the Japanese in World War II with plague-infected fleas and cholera-coated flies and of the Americans during the Cold War with yellow fever-infected mosquitoes. With continued advances, defenses in the form of insecticides and vaccines meant that insects were no longer considered as battlefield weapons. However, in recent times sociopolitical changes have put insects back into the realm of human conflict through asymmetrical conflicts pitting combatants from nonindustrialized regions against forces from militarily and economically superior nations. PMID:21910635

  7. Detection of insects in grain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Detecting insects hidden inside kernels of grain is important to grain buyers because internal infestations can result in insect fragments in products made from the grain, or, if the grain is stored before use, the insect population can increase and damage the grain further. In a study in the Unite...

  8. Insect Ferritins: typical or atypical?

    PubMed Central

    Pham, Daphne Q. D.; Winzerling, Joy J.

    2010-01-01

    Insects transmit millions of cases of disease each year, and cost millions of dollars in agricultural losses. The control of insect-borne diseases is vital for numerous developing countries, and the management of agricultural insect pests is a very serious business for developed countries. Control methods should target insect-specific traits in order to avoid non-target effects, especially in mammals. Since insect cells have had a billion years of evolutionary divergence from those of vertebrates, they differ in many ways that might be promising for the insect control field—especially, in iron metabolism because current studies have indicated that significant differences exist between insect and mammalian systems. Insect iron metabolism differs from that of vertebrates in the following respects. Insect ferritins have a heavier mass than mammalian ferritins. Unlike their mammalian counterparts, the insect ferritin subunits are often glycosylated and are synthesized with a signal peptide. The crystal structure of insect ferritin also shows a tetrahedral symmetry consisting of 12 heavy chain and 12 light chain subunits in contrast to that of mammalian ferritin that exhibits an octahedral symmetry made of 24 heavy chain and 24 light chain subunits. Insect ferritins associate primarily with the vacuolar system and serve as iron transporters—quite the opposite of the mammalian ferritins, which are mainly cytoplasmic and serve as iron storage proteins. This review will discuss these differences. PMID:20230873

  9. Pathogen intelligence

    PubMed Central

    Steinert, Michael

    2014-01-01

    Different species inhabit different sensory worlds and thus have evolved diverse means of processing information, learning and memory. In the escalated arms race with host defense, each pathogenic bacterium not only has evolved its individual cellular sensing and behavior, but also collective sensing, interbacterial communication, distributed information processing, joint decision making, dissociative behavior, and the phenotypic and genotypic heterogeneity necessary for epidemiologic success. Moreover, pathogenic populations take advantage of dormancy strategies and rapid evolutionary speed, which allow them to save co-generated intelligent traits in a collective genomic memory. This review discusses how these mechanisms add further levels of complexity to bacterial pathogenicity and transmission, and how mining for these mechanisms could help to develop new anti-infective strategies. PMID:24551600

  10. Evolution and the microbial control of insects

    PubMed Central

    Cory, Jenny S; Franklin, Michelle T

    2012-01-01

    Insect pathogens can be utilized in a variety of pest management approaches, from inundative release to augmentation and classical biological control, and microevolution and the consideration of evolutionary principles can potentially influence the success of all these strategies. Considerable diversity exists in natural entomopathogen populations and this diversity can be either beneficial or detrimental for pest suppression, depending on the pathogen and its mode of competition, and this should be considered in the selection of isolates for biological control. Target hosts can exhibit considerable variation in their susceptibility to entomopathogens, and cases of field-evolved resistance have been documented for Bacillus thuringiensis and baculoviruses. Strong selection, limited pathogen diversity, reduced gene flow, and host plant chemistry are linked to cases of resistance and should be considered when developing resistance management strategies. Pre- and post-release monitoring of microbial control programs have received little attention; however, to date there have been no reports of host-range evolution or long-term negative effects on nontarget hosts. Comparative analyses of pathogen population structure, virulence, and host resistance over time are required to elucidate the evolutionary dynamics of microbial control systems. PMID:22949921

  11. Endosymbiont Tolerance and Control within Insect Hosts

    PubMed Central

    Ratzka, Carolin; Gross, Roy; Feldhaar, Heike

    2012-01-01

    Bacterial endosymbioses are very common in insects and can range from obligate to facultative as well as from mutualistic to pathogenic associations. Several recent studies provide new insight into how endosymbionts manage to establish chronic infections of their hosts without being eliminated by the host immune system. Endosymbiont tolerance may be achieved either by specific bacterial adaptations or by host measurements shielding bacteria from innate defense mechanisms. Nevertheless, insect hosts also need to sustain control mechanisms to prevent endosymbionts from unregulated proliferation. Emerging evidence indicates that in some cases the mutual adaptations of the two organisms may have led to the integration of the endosymbionts as a part of the host immune system. In fact, endosymbionts may provide protective traits against pathogens and predators and may even be required for the proper development of the host immune system during host ontogeny. This review gives an overview of current knowledge of molecular mechanisms ensuring maintenance of chronic infections with mutualistic endosymbionts and the impact of endosymbionts on host immune competence. PMID:26466544

  12. On quantifying insect movements

    SciTech Connect

    Wiens, J.A.; Crist, T.O. ); Milne, B.T. )

    1993-08-01

    We elaborate on methods described by Turchin, Odendaal Rausher for quantifying insect movement pathways. We note the need to scale measurement resolution to the study insects and the questions being asked, and we discuss the use of surveying instrumentation for recording sequential positions of individuals on pathways. We itemize several measures that may be used to characterize movement pathways and illustrate these by comparisons among several Eleodes beetles occurring in shortgrass steppe. The fractal dimension of pathways may provide insights not available from absolute measures of pathway configuration. Finally, we describe a renormalization procedure that may be used to remove sequential interdependence among locations of moving individuals while preserving the basic attributes of the pathway.

  13. Fungal dimorphism in the entomopathogenic fungus Metarhizium rileyi: detection of an in vivo quorum-sensing system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This investigation documents the expression of the in vivo dimorphic program exhibited by insect mycopathogen M. rileyi replicating. This insect mycopathogen represents the key mortality factor regulating various caterpillar populations in various legumes, including subtropical and tropical soybeans...

  14. Undergraduates' mental models about insect anatomy and insect life cycles

    NASA Astrophysics Data System (ADS)

    Diaz, Arlene Edith

    Educational studies focused on students' alternative conceptions have shown the importance of developing strategies to correct understanding. Identifying and comprehending student mental models are important since they may reflect alternate conceptions about scientific concepts. Mental models have been identified in various science education studies, but little is known about mental models undergraduates hold about insects. This research is significant because it identified mental models undergraduates have about insect anatomy and insect life cycles, exposed students to cognitive conflict by having them complete an online insect tutorial, and analyzed the effectiveness of this insect tutorial in correcting student understanding. An insect assessment was developed and administered pre- and post-instruction to probe students' mental models about insects. Different numbers of undergraduate students participated in different parts of the assessment; 276, 249, 166, and 58 students participated in the listing, drawing. definition, and life cycle parts of the assessment, respectively. The tutorial contained a variety of manipulated insect and non-insect images that challenged the students' understanding and generated cognitive conflict. This intervention guided students in replacing alternate conceptions with correct understanding. It was hypothesized that the tutorial would have a positive impact on student learning about insects. The results suggest that the tutorial had a positive impact on learning.

  15. [Protection against insects].

    PubMed

    Rudin, W

    2005-11-01

    Successful protection against haematophagous insects and ticks, especially in areas where transmission of diseases occurs, requires a consistent application of a combination of appropriate measures. However, this can never substitute a chemoprophylaxis. Which measures have to be used depends on the circumstances under which they have to work. Indoor, physical means such as mosquito-screens on doors and windows, air-conditioners, and bed nets can be used to keep the insects away. These measures can be supplemented or supported by insecticides used as knock-down sprays, by electrical evaporation or for the treatment of screens and bed nets. In the field, if it is not possible to avoid mosquito-areas during phases of activity, appropriate clothing and repellents must provide the protection. Bright, wide pants and shirts of dense weaving covering as much skin as bearable should be preferred. Repellents are sprays, lotions, milks or creams which are evenly applied to the skin to prevent insects from biting. They contain synthetic or natural active substances of substantially varying effectiveness. The gold standard since about 60 years is diethylbenzamine (DEET). There are a few other active substances with a lower risk of side effects, however, combined with a lower effectiveness mainly on people with a high attractiveness for mosquitoes. Products containing an extract of Eucalyptus citriodora provide the best protection amongst those with natural active substances. Wearing bracelets or necklaces treated with repellents, acoustic devices (buzzers), electrocuters, topical or systemic Vitamin B1 or eating garlic are useless measures to prevent insects from biting. PMID:16350532

  16. Interrogating an insect society

    PubMed Central

    Gadagkar, Raghavendra

    2009-01-01

    Insect societies such as those of ants, bees, and wasps consist of 1 or a small number of fertile queens and a large number of sterile or nearly sterile workers. While the queens engage in laying eggs, workers perform all other tasks such as nest building, acquisition and processing of food, and brood care. How do such societies function in a coordinated and efficient manner? What are the rules that individuals follow? How are these rules made and enforced? These questions are of obvious interest to us as fellow social animals but how do we interrogate an insect society and seek answers to these questions? In this article I will describe my research that was designed to seek answers from an insect society to a series of questions of obvious interest to us. I have chosen the Indian paper wasp Ropalidia marginata for this purpose, a species that is abundantly distributed in peninsular India and serves as an excellent model system. An important feature of this species is that queens and workers are morphologically identical and physiologically nearly so. How then does an individual become a queen? How does the queen suppress worker reproduction? How does the queen regulate the nonreproductive activities of the workers? What is the function of aggression shown by different individuals? How and when is the queen's heir decided? I will show how such questions can indeed be investigated and will emphasize the need for a whole range of different techniques of observation and experimentation. PMID:19487678

  17. Fatigue of insect cuticle.

    PubMed

    Dirks, Jan-Henning; Parle, Eoin; Taylor, David

    2013-05-15

    Many parts of the insect exoskeleton experience repeated cyclic loading. Although the cuticle of insects and other arthropods is the second most common natural composite material in the world, so far nothing is known about its fatigue properties, despite the fact that fatigue undoubtedly limits the durability of body parts in vivo. For the first time, we here present experimental fatigue data of insect cuticle. Using force-controlled cyclic loading, we determined the number of cycles to failure for hind legs (tibiae) and hind wings of the locust Schistocerca gregaria, as a function of the applied cyclic stress. Our results show that, although both are made from cuticle, these two body parts behave very differently. Wing samples showed a large fatigue range, failing after 100,000 cycles when we applied 46% of the stress needed for instantaneous failure [the ultimate tensile strength (UTS)]. Legs, in contrast, were able to sustain a stress of 76% of the UTS for the same number of cycles to failure. This can be explained by the difference in the composition and structure of the material, two factors that, amongst others, also affect the well-known behaviour of engineering composites. Final failure of the tibiae occurred via one of two different failure modes--propagation in tension or buckling in compression--indicating that the tibia is 'optimized' by evolution to resist both failure modes equally. These results are further discussed in relation to the evolution and normal use of these two body parts. PMID:23393276

  18. Escape behaviors in insects.

    PubMed

    Card, Gwyneth M

    2012-04-01

    Escape behaviors are, by necessity, fast and robust, making them excellent systems with which to study the neural basis of behavior. This is especially true in insects, which have comparatively tractable nervous systems and members who are amenable to manipulation with genetic tools. Recent technical developments in high-speed video reveal that, despite their short duration, insect escape behaviors are more complex than previously appreciated. For example, before initiating an escape jump, a fly performs sophisticated posture and stimulus-dependent preparatory leg movements that enable it to jump away from a looming threat. This newfound flexibility raises the question of how the nervous system generates a behavior that is both rapid and flexible. Recordings from the cricket nervous system suggest that synchrony between the activity of specific interneuron pairs may provide a rapid cue for the cricket to detect the direction of an approaching predator and thus which direction it should run. Technical advances make possible wireless recording from neurons while locusts escape from a looming threat, enabling, for the first time, a direct correlation between the activity of multiple neurons and the time-course of an insect escape behavior. PMID:22226514

  19. NRPS4 is responsible for the biosynthesis of destruxins in Metarhizium robertsii ARSEF 2575

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Destruxins (DTXs) are a family of cyclic depsipeptides that include > 35 members produced by Ascomycetous fungi belonging to several different taxa. These metabolites display a plethora of biological activities including toxicity against insects, depolarization of Ca2+ gradient across the plasma mem...

  20. Efficacy of the entomopathogenic fungus Metarhizium brunneum in controlling the tick Rhipicephalus annulatus under field conditions.

    PubMed

    Samish, M; Rot, A; Ment, D; Barel, S; Glazer, I; Gindin, G

    2014-12-15

    High infectivity of entomopathogenic fungi to ticks under laboratory conditions has been demonstrated in many studies. However, the few reports on their use under field conditions demonstrate large variations in their success, often with no clear explanation. The present study evaluated the factors affecting the efficacy of the fungus Metarhizium brunneum against the tick Rhipicephalus (Boophilus) annulatus. It demonstrates how environmental conditions and ground cover affect the efficiency of the fungus under field conditions. During the summer, 93% of tick females exposed to fungus-contaminated ground died within 1 week, whereas during the winter, only 62.2% died within 6 weeks. Nevertheless, the hatchability of their eggs was only 6.1% during the summer and 0.0% during winter. Covering the ground with grass, leaves or gravel improved fungal performance. Aside from killing female ticks, the fungus had a substantial effect on tick fecundity. Fungal infection reduced the proportion of female ticks laying full-size egg masses by up to 91%, and reduced egg hatchability by up to 100%. To reduce the negative effect of outdoor factors on fungal activity, its conidia were mixed with different oils (olive, canola, mineral or paraffin at 10% v/v) and evaluated in both laboratory and field tests for efficacy. All tested oils without conidia sprayed on the sand did not influence tick survival or weight of the laid eggs but significantly reduced egghatchability. Conidia in water with canola or mineral oil spread on agarose and incubated for 18 h showed 57% and 0% germination, respectively. Comparing, under laboratory conditions, the effects of adding each of the four oils to conidia in water on ticks demonstrated no effect on female mortality or weight of the laid egg mass, but the percentage of hatched eggs was reduced. In outdoor trials, female ticks placed on the ground sprayed with conidia in water yielded an average of 175 larvae per female and there was no hatching of

  1. Comparison of respiratory responses to Metarhizium anisopliae extract using two different sensitization protocols.

    PubMed

    Ward, M D; Madison, S L; Andrews, D L; Sailstad, D M; Gavett, S H; Selgrade, M J

    2000-06-01

    Metarhizium anisopliae, an entomopathogenic fungus, is a prototypic microbial pesticide licensed for indoor control of cockroaches, a major source of allergens. We have previously demonstrated allergy and asthma-like responses in BALB/c mice intraperitoneally (IP) sensitized in the presence of adjuvant and intratracheally (IT) challenged with the soluble factors from M. anisopliae crude antigen (MACA) (Ward et al., 1998, 2000). This protocol has been used frequently to establish animal models of allergenicity. However, the sensitization protocol is artificial and not representative of an environmental exposure. Concern has been raised that this protocol might produce allergic responses that would not occur under normal environmental exposure conditions. The objective of this study was to compare responses in mice to MACA by two exposure protocols: (1) exclusive respiratory exposures without adjuvant (representative of environmental exposures) and (2) intraperitoneal sensitization in the presence of adjuvant followed by IT challenge (the traditional approach). The intratracheal protocol consisted of four IT exposures of 10 microg MACA in 50 microl HBSS each over a 4-week period. A vehicle control group of mice was exposed IT to HBSS. The intraperitoneal protocol consisted of IP sensitization with 25 microg MACA in 0.2 ml of 1.3% alhydrogel (aluminum hydroxide) followed 14 days later with an IT challenge (10 microg MACA/50 microl HBSS). Airway reactivity responsiveness to methacholine was assessed, serum and bronchoalveolar lavage fluid (BALF) samples were obtained, and the lungs were fixed for histopathology at 1, 3, and 8 days following the last MACA IT challenge. Both groups exhibited immune and pulmonary responses typical of allergic asthma. In general, local responses in the lung, including inflammatory responses (eosinophils, lymphocytes, and macrophages), BALF IgE, and functional responses to methacholine were greater in the IT sensitized group compared to the

  2. Differential allergy responses to Metarhizium anisopliae fungal component extracts in BALB/c mice.

    PubMed

    Ward, Marsha D W; Chung, Yong Joo; Haykal-Coates, Najwa; Copeland, Lisa B

    2009-03-01

    Intratracheal aspiration (IA) exposure to Metarhizium anisopliae crude antigen (MACA), which is composed of equal protein amounts of mycelium (MYC), conidia (CON) and inducible proteases/chitinases (IND) extracts/filtrates, has resulted in responses characteristic of human allergic asthma in mice. The study objective was to evaluate the potential of each component extract to induce allergic/asthma-like responses observed in this mouse model. BALB/c mice received 4 IA exposures to MACA, CON, MYC, IND, or bovine serum albumin (BSA; negative control) or appropriate vehicle control or inflammatory control over a 4-wk period. Mice were assessed by whole-body plethysmography for immediate airway responses and airway hyperresponsiveness to methacholine (Mch) challenge (PenH). Serum and bronchoalveolar lavage fluid (BALF) were collected 3 d after the final exposure. Additionally, BALF neurotrophin levels and extract protease and chitinase activity levels were evaluated. Western blot analysis showed that each component contained different IgE-reactive proteins. All fungal extract exposures resulted in elevated BALF total and differential cell counts, IgE and IgA and total serum IgE compared to HBSS and BSA controls. MYC-exposed mice had the highest responses except for neutrophil influx, which was highest in MACA and IND exposures. However, the MYC-exposed mice had significantly lower PenH values compared to other treatments. By comparison IND and MACA induced significantly higher PenH values. Additionally, IND had substantially higher protease activity levels but induced the lowest neurotrophin levels compared to the other fungal exposures. In this allergic asthma model extract chitinase activity was not associated with allergic responses. In summary, multiple exposures to any of the M. anisopliae component extracts induced allergic/asthma-like responses in BALB/c mice but the response magnitude was different for each component and each appears to contain unique Ig

  3. Allergen-triggered airway hyperresponsiveness and lung pathology in mice sensitized with the biopesticide Metarhizium anisopliae.

    PubMed

    Ward, M D; Madison, S L; Sailstad, D M; Gavett, S H; Selgrade, M K

    2000-02-21

    Metarhizium anisopliae is an entomopathogenic fungus recently licensed for indoor control of cockroaches, a major source of allergens. While M. anisopliae has been shown to be non-infectious and non-toxic to mammals there has been only limited research on potential allergenicity. Using a mouse model, we previously demonstrated allergic immune and inflammatory responses to this agent. The present study was designed to determine whether these responses were associated with changes in pulmonary responses, lung pathology, and the cytokine profile in bronchoalveolar lavage fluid (BALF). Soluble factors from fungal components were combined in equal protein amounts to form M. anisopliae crude antigen (MACA). BALB/C mice were intratracheally (i.t.) challenged with 10 microg MACA 14 days post intraperitoneal sensitization with 25 microg fungal antigen in aluminum hydroxide adjuvant. Physiological and cellular changes were examined. The mice were tested for airway hyperresponsiveness before (No Chal) and after (1, 3, and 8 days post challenge (DPIT)) MACA IT challenge. Subsequently, serum, BALF and the lungs were harvested. All treatment groups concurrently demonstrated significant non-specific pulmonary inflammation (neutrophil influx) and increased pulmonary sensitivity to methacholine (Mch) at 1 DPIT MACA challenge. Where as both adjuvant treated and naïve mice airway responses had returned to near normal levels by 3 DPIT, mice which were previously sensitized with MACA were still hyperresponsive to Mch challenge at 3 and 8 DPIT. This hyperresponsiveness correlates with eosinophil and lymphocyte influx, which is maximal at 3 DPIT and still elevated at 8 DPIT. Interleukin (IL) 5 was elevated for all treatment groups at 1 DPIT but only the MACA sensitized mice maintained elevated levels for both 3 and 8 DPIT. Furthermore, MACA sensitized mice had a more extensive inflammatory histopathology at all examined time points with peribronchial and perivascular infiltrates, like

  4. Insect pathogens as biological control agents: back to the future

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the past 15 years a number of successes and setbacks have taken place regarding development and use of microbial control agents. In this Forum paper we present current information on development, use and future directions of entomopathogenic virus, bacteria, fungi and nematodes as components of i...

  5. Transient endophytic colonizations of plants improve the outcome of foliar applications of mycoinsecticides against chewing insects.

    PubMed

    Resquín-Romero, G; Garrido-Jurado, I; Delso, C; Ríos-Moreno, A; Quesada-Moraga, E

    2016-05-01

    The current work reports how spray application of entomopathogenic fungi on alfalfa, tomato and melon plants may cause an additional Spodoptera littoralis larvae mortality due to a temporal colonization of the leaves and subsequent ingestion of those leaves by the larvae. Most entomopathogenic fungi (EF) (Ascomycota: Hypocreales) endophytes seem to colonize their host plants in a non-systemic pattern, in which case at least a transient endophytic establishment of the fungus should be expected in treated areas after spray application. In this work, all strains were able to endophytically colonize roots, stems and leaves during the first 96h after inoculation. Whilst the treatment of S. littoralis larvae with a 10(8)ml(-1) conidial suspension resulted in moderate to high mortality rates for the Metarhizium brunneum EAMb 09/01-Su (41.7-50.0%) and Beauveria bassiana EABb 01/33-Su (66.7-76.6%) strains, respectively, an additive effect was detected when these larvae were also fed endophytically colonized alfalfa, tomato, and melon leaves, with mortality rates varying from 25.0% to 46.7% as a function of the host plant and total mortality rates in the combined treatment of 75-80% and 33-60% for B. bassiana and M. brunneum, respectively. Fungal outgrowth was not detected in any of the dead larvae feeding on colonized leaves, whereas traces of destruxin A were detected in 11% of the insects fed tomato discs endophytically colonized by M. brunneum. The combined effects of the fungal spray with the mortality caused by the feeding of insects on transient EF-colonized leaves have to be considered to estimate the real acute impact of field sprays with entomopathogenic fungi on chewing insects. PMID:26945771

  6. Dietary Cholesterol Modulates Pathogen Blocking by Wolbachia

    PubMed Central

    Caragata, Eric P.; Rancès, Edwige; Hedges, Lauren M.; Gofton, Alexander W.; Johnson, Karyn N.; O'Neill, Scott L.; McGraw, Elizabeth A.

    2013-01-01

    The bacterial endosymbiont Wolbachia pipientis protects its hosts from a range of pathogens by limiting their ability to form infections inside the insect. This “pathogen blocking” could be explained by innate immune priming by the symbiont, competition for host-derived resources between pathogens and Wolbachia, or the direct modification of the cell or cellular environment by Wolbachia. Recent comparative work in Drosophila and the mosquito Aedes aegypti has shown that an immune response is not required for pathogen blocking, implying that there must be an additional component to the mechanism. Here we have examined the involvement of cholesterol in pathogen blocking using a system of dietary manipulation in Drosophila melanogaster in combination with challenge by Drosophila C virus (DCV), a common fly pathogen. We observed that flies reared on cholesterol-enriched diets infected with the Wolbachia strains wMelPop and wMelCS exhibited reduced pathogen blocking, with viral-induced mortality occurring 2–5 days earlier than flies reared on Standard diet. This shift toward greater virulence in the presence of cholesterol also corresponded to higher viral copy numbers in the host. Interestingly, an increase in dietary cholesterol did not have an effect on Wolbachia density except in one case, but this did not directly affect the strength of pathogen blocking. Our results indicate that host cholesterol levels are involved with the ability of Wolbachia-infected flies to resist DCV infections, suggesting that cholesterol contributes to the underlying mechanism of pathogen blocking. PMID:23825950

  7. Toll receptors and pathogen resistance.

    PubMed

    Takeda, Kiyoshi; Akira, Shizuo

    2003-03-01

    Toll receptors in insects, mammals and plants are key players that sense the invasion of pathogens. Toll-like receptors (TLRs) in mammals have been established to detect specific components of bacterial and fungal pathogens. Furthermore, recent evidence indicates that TLRs are involved in the recognition of viral invasion. Signalling pathways via TLRs originate from the conserved Toll/IL-1 receptor (TIR) domain. The TIR domain-containing MyD88 acts as a common adaptor that induces inflammatory cytokines; however, there exists a MyD88-independent pathway that induces type I IFNs in TLR4 and TLR3 signalling. Another TIR domain-containing adaptor, TIRAP/Mal has recently been shown to mediate the MyD88-dependent activation in the TLR4 and TLR2 signalling pathway. Thus, individual TLRs may have their own signalling systems that characterize their specific activities. PMID:12614458

  8. Intestinal regeneration as an insect resistance mechanism to entomopathogenic bacteria.

    PubMed

    Castagnola, Anaïs; Jurat-Fuentes, Juan Luis

    2016-06-01

    The intestinal epithelium of insects is exposed to xenobiotics and entomopathogens during the feeding developmental stages. In these conditions, an effective enterocyte turnover mechanism is highly desirable to maintain integrity of the gut epithelial wall. As in other insects, the gut of lepidopteran larvae have stem cells that are capable of proliferation, which occurs during molting and pathogenic episodes. While much is known on the regulation of gut stem cell division during molting, there is a current knowledge gap on the molecular regulation of gut healing processes after entomopathogen exposure. Relevant information on this subject is emerging from studies of the response to exposure to insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) as model intoxicants. In this work we discuss currently available data on the molecular cues involved in gut stem cell proliferation, insect gut healing, and the implications of enhanced healing as a potential mechanism of resistance against Bt toxins. PMID:27436739

  9. Real encoded genetic algorithm and response surface methodology to optimize production of an indolizidine alkaloid, swainsonine, from Metarhizium anisopliae.

    PubMed

    Singh, Digar; Kaur, Gurvinder

    2013-09-01

    Response surface methodology (RSM) and artificial neural network-real encoded genetic algorithm (ANN-REGA) were employed to develop a process for fermentative swainsonine production from Metarhizium anisopliae (ARSEF 1724). The effect of finally screened process variables viz. inoculum size, oatmeal extract, glucose, and CaCl2 were investigated through central composite design and were further utilized for training sets in ANN with training and test R values of 0.99 and 0.94, respectively. ANN-REGA was finally employed to simulate the predictive swainsonine production with best evolved media composition. ANN-REGA predicted a more precise fermentation model with 103 % (shake flask) increase in alkaloid production compared to 75.62 % (shake flask) obtained with RSM model upon validation. PMID:23315485

  10. Insect bite prevention.

    PubMed

    Moore, Sarah J; Mordue Luntz, Anne Jennifer; Logan, James G

    2012-09-01

    Protection from the bites of arthropod (insect and acarine) vectors of disease is the first line of defense against disease transmission and should be advised in all cases when traveling abroad. Details are described of the main approaches for the prevention of bites, including topical or skin repellents, impregnated clothing, bed nets, and spatial or aerial repellents and aerosols. The bionomics of the main arthropod vectors of disease are described along with photographic plates and tabulated advice to give the traveler. An in-depth treatment of the different protection methodologies provides an up-to-date overview of the technologies involved. PMID:22963776

  11. Aircraft anti-insect system

    NASA Technical Reports Server (NTRS)

    Spiro, Clifford Lawrence (Inventor); Fric, Thomas Frank (Inventor); Leon, Ross Michael (Inventor)

    1997-01-01

    Insect debris is removed from or prevented from adhering to insect impingement areas of an aircraft, particularly on an inlet cowl of an engine, by heating the area to 180.degree.-500.degree. C. An apparatus comprising a means to bring hot air from the aircraft engine to a plenum contiguous to the insect impingement area provides for the heating of the insect impingement areas to the required temperatures. The plenum can include at least one tube with a plurality of holes contained in a cavity within the inlet cowl. It can also include an envelope with a plurality of holes on its surface contained in a cavity within the inlet cowl.

  12. An overview of antifungal peptides derived from insect.

    PubMed

    Faruck, Mohammad Omer; Yusof, Faridah; Chowdhury, Silvia

    2016-06-01

    Fungi are not classified as plants or animals. They resemble plants in many ways but do not produce chlorophyll or make their own food photosynthetically like plants. Fungi are useful for the production of beer, bread, medicine, etc. More complex than viruses or bacteria; fungi can be destructive human pathogens responsible for various diseases in humans. Most people have a strong natural immunity against fungal infection. However, fungi can cause diseases when this immunity breaks down. In the last few years, fungal infection has increased strikingly and has been accompanied by a rise in the number of deaths of cancer patients, transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients owing to fungal infections. The growth rate of fungi is very slow and quite difficult to identify. A series of molecules with antifungal activity against different strains of fungi have been found in insects, which can be of great importance to tackle human diseases. Insects secrete such compounds, which can be peptides, as a part of their immune defense reactions. Active antifungal peptides developed by insects to rapidly eliminate infectious pathogens are considered a component of the defense munitions. This review focuses on naturally occurring antifungal peptides from insects and their challenges to be used as armaments against human diseases. PMID:26093218

  13. Phytohormone mediation of interactions between herbivores and plant pathogens.

    PubMed

    Lazebnik, Jenny; Frago, Enric; Dicke, Marcel; van Loon, Joop J A

    2014-07-01

    Induced plant defenses against either pathogens or herbivore attackers are regulated by phytohormones. These phytohormones are increasingly recognized as important mediators of interactions between organisms associated with plants. In this review, we discuss the role of plant defense hormones in sequential tri-partite interactions among plants, pathogenic microbes, and herbivorous insects, based on the most recent literature. We discuss the importance of pathogen trophic strategy in the interaction with herbivores that exhibit different feeding modes. Plant resistance mechanisms also affect plant quality in future interactions with attackers. We discuss exemplary evidence for the hypotheses that (i) biotrophic pathogens can facilitate chewing herbivores, unless plants exhibit effector-triggered immunity, but (ii) facilitate or inhibit phloem feeders. (iii) Necrotrophic pathogens, on the other hand, can inhibit both phloem feeders and chewers. We also propose herbivore feeding mode as predictor of effects on pathogens of different trophic strategies, providing evidence for the hypotheses that (iv) phloem feeders inhibit pathogen attack by increasing SA induction, whereas (v) chewing herbivores tend not to affect necrotrophic pathogens, while they may either inhibit or facilitate biotrophic pathogens. Putting these hypotheses to the test will increase our understanding of phytohormonal regulation of plant defense to sequential attack by plant pathogens and insect herbivores. This will provide valuable insight into plant-mediated ecological interactions among members of the plant-associated community. PMID:25059974

  14. A model of insect—pathogen dynamics in which a pathogenic bacterium can also reproduce saprophytically

    PubMed Central

    Godfray, H. C. J.; Briggs, C. J.; Barlow, N. D.; O'Callaghan, M.; Glare, T. R.; Jackson, T. A.

    1999-01-01

    We developed a model of the population dynamic interaction between an insect and a pathogenic bacterium motivated by study of Serratia entomophila, a commercially exploited pathogen of the New Zealand grass grub (Costelytra zealandica). The bacterium is able to reproduce saprophytically, though it competes for saprophytic substrates with non-pathogenic strains, which appear to be superior competitors, probably because they lack a plasmid that carries genes required for pathogenicity. The effect of saprophytism and competition on the invasion criterion (R0), short-term dynamics and long-term dynamics are described. Saprophytism can reduce (possibly to zero) the host threshold at which the pathogen can invade, though this reduction is less when there is competition with non-pathogenic strains. In a model of short-term population dynamics designed to mimic the application of bacteria to a host epizootic, saprophytism enhances the reduction in host density, though again this is tempered by competition with non-pathogens. In the long term, a pathogen that can develop saprophytically can drive its host to extinction in the absence of competition with non-pathogens. When the latter are present, host extinction is prevented. The addition of saprophytic reproduction can stabilize an otherwise unstable host–pathogen model, but we were unable to find a stable equilibrium given the further addition of a wholly saprophytic bacterial strain. The model suggests that enhancing or selecting for saprophytic ability could be a way of improving biological control.

  15. Methods of correlating electropenetrography waveform data to Hemipteran probing behavior and pathogen transmission

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hemipteran feeding behavior cannot be visualized within plant tissues by researchers studying probing and/or transmission attributes of some economically important plant pathogens transmitted by these piercing sucking insects. Electropenetrography (EPG) is currently the most precise method for study...

  16. 1977 Kansas Field Crop Insect Control Recommendations.

    ERIC Educational Resources Information Center

    Brooks, Leroy; Gates, Dell E.

    This publication is prepared to aid producers in selecting methods of insect population management that have proved effective under Kansas conditions. Topics covered include insect control on alfalfa, soil insects attacking corn, insects attacking above-ground parts of corn, and sorghum, wheat, and soybean insect control. The insecticides…

  17. 7 CFR 51.2122 - Insect injury.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Insect injury. 51.2122 Section 51.2122 Agriculture... Standards for Grades of Shelled Almonds Definitions § 51.2122 Insect injury. Insect injury means that the insect, web, or frass is present or there is definite evidence of insect feeding....

  18. 7 CFR 51.2290 - Insect injury.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Insect injury. 51.2290 Section 51.2290 Agriculture... Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2290 Insect injury. Insect injury means that the insect, web, frass or other evidence of insects is present on the portion of kernel....

  19. 7 CFR 51.2008 - Insect injury.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Insect injury. 51.2008 Section 51.2008 Agriculture....2008 Insect injury. Insect injury means that the insect, frass or web is present inside the nut or the kernel shows definite evidence of insect feeding. Metric Conversion Table...

  20. 7 CFR 51.2290 - Insect injury.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Insect injury. 51.2290 Section 51.2290 Agriculture... Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2290 Insect injury. Insect injury means that the insect, web, frass or other evidence of insects is present on the portion of kernel....

  1. 7 CFR 51.2290 - Insect injury.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Insect injury. 51.2290 Section 51.2290 Agriculture... Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2290 Insect injury. Insect injury means that the insect, web, frass or other evidence of insects is present on the portion of kernel....

  2. 7 CFR 51.2122 - Insect injury.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Insect injury. 51.2122 Section 51.2122 Agriculture... Standards for Grades of Shelled Almonds Definitions § 51.2122 Insect injury. Insect injury means that the insect, web, or frass is present or there is definite evidence of insect feeding....

  3. 7 CFR 51.2008 - Insect injury.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Insect injury. 51.2008 Section 51.2008 Agriculture....2008 Insect injury. Insect injury means that the insect, frass or web is present inside the nut or the kernel shows definite evidence of insect feeding. Metric Conversion Table...

  4. 7 CFR 51.2122 - Insect injury.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Insect injury. 51.2122 Section 51.2122 Agriculture... Standards for Grades of Shelled Almonds Definitions § 51.2122 Insect injury. Insect injury means that the insect, web, or frass is present or there is definite evidence of insect feeding....

  5. Insect-specific flaviviruses, a worldwide widespread group of viruses only detected in insects.

    PubMed

    Calzolari, Mattia; Zé-Zé, Líbia; Vázquez, Ana; Sánchez Seco, Mari Paz; Amaro, Fátima; Dottori, Michele

    2016-06-01

    Several flaviviruses are important pathogens for humans and animals (Dengue viruses, Japanese encephalitis virus, Yellow-fever virus, Tick-borne encephalitis virus, West Nile virus). In recent years, numerous novel and related flaviviruses without known pathogenic capacity have been isolated worldwide in the natural mosquito population. However, phylogenetic studies have shown that genomic sequences of these viruses diverge from other flaviviruses. Moreover, these viruses seem to be exclusive of insects (they do not seem to grow on vertebrate cell lines), and were already defined as mosquito-only flaviviruses or insect-specific flaviviruses. At least eleven of these viruses were isolated worldwide, and sequences ascribable to other eleven putative viruses were detected in several mosquito species. A large part of the cycle of these viruses is not well known, and their persistence in the environment is poorly understood. These viruses are detected in a wide variety of distinct mosquito species and also in sandflies and chironomids worldwide; a single virus, or the genetic material ascribable to a virus, was detected in several mosquito species in different countries, often in different continents. Furthermore, some of these viruses are carried by invasive mosquitoes, and do not seem to have a depressive action on their fitness. The global distribution and the continuous detection of new viruses in this group point out the likely underestimation of their number, and raise interesting issues about their possible interactions with the pathogenic flaviviruses, and their influence on the bionomics of arthropod hosts. Some enigmatic features, as their integration in the mosquito genome, the recognition of their genetic material in DNA forms in field-collected mosquitoes, or the detection of the same virus in both mosquitoes and sandflies, indicate that the cycle of these viruses has unknown characteristics that could be of use to reach a deeper understanding of the cycle

  6. Disease Dynamics in Ants: A Critical Review of the Ecological Relevance of Using Generalist Fungi to Study Infections in Insect Societies.

    PubMed

    Loreto, R G; Hughes, D P

    2016-01-01

    It is assumed that social life can lead to the rapid spread of infectious diseases and outbreaks. In ants, disease outbreaks are rare and the expression of collective behaviors is invoked to explain the absence of epidemics in natural populations. Here, we address the ecological approach employed by many studies that have notably focused (89% of the studies) on two genera of generalist fungal parasites (Beauveria and Metarhizium). We ask whether these are the most representative models to study the evolutionary ecology of ant-fungal parasite interactions. To assess this, we critically examine the literature on ants and their interactions with fungal parasites from the past 114years (1900-2014). We discuss how current evolutionary ecology approaches emerged from studies focused on the biological control of pest ants. We also analyzed the ecological relevance of the laboratory protocols used in evolutionary ecology studies employing generalist parasites, as well as the rare natural occurrence of these parasites on ants. After a detailed consideration of all the publications, we suggest that using generalist pathogens such as Beauveria and Metarhizium is not an optimal approach if the goal is to study the evolutionary ecology of disease in ants. We conclude by advocating for approaches that incorporate greater realism. PMID:27131328

  7. Hydrodynamics of insect spermatozoa

    NASA Astrophysics Data System (ADS)

    Pak, On Shun; Lauga, Eric

    2010-11-01

    Microorganism motility plays important roles in many biological processes including reproduction. Many microorganisms propel themselves by propagating traveling waves along their flagella. Depending on the species, propagation of planar waves (e.g. Ceratium) and helical waves (e.g. Trichomonas) were observed in eukaryotic flagellar motion, and hydrodynamic models for both were proposed in the past. However, the motility of insect spermatozoa remains largely unexplored. An interesting morphological feature of such cells, first observed in Tenebrio molitor and Bacillus rossius, is the double helical deformation pattern along the flagella, which is characterized by the presence of two superimposed helical flagellar waves (one with a large amplitude and low frequency, and the other with a small amplitude and high frequency). Here we present the first hydrodynamic investigation of the locomotion of insect spermatozoa. The swimming kinematics, trajectories and hydrodynamic efficiency of the swimmer are computed based on the prescribed double helical deformation pattern. We then compare our theoretical predictions with experimental measurements, and explore the dependence of the swimming performance on the geometric and dynamical parameters.

  8. Diversity, evolution and medical applications of insect antimicrobial peptides.

    PubMed

    Mylonakis, Eleftherios; Podsiadlowski, Lars; Muhammed, Maged; Vilcinskas, Andreas

    2016-05-26

    Antimicrobial peptides (AMPs) are short proteins with antimicrobial activity. A large portion of known AMPs originate from insects, and the number and diversity of these molecules in different species varies considerably. Insect AMPs represent a potential source of alternative antibiotics to address the limitation of current antibiotics, which has been caused by the emergence and spread of multidrug-resistant pathogens. To get more insight into AMPs, we investigated the diversity and evolution of insect AMPs by mapping their phylogenetic distribution, allowing us to predict the evolutionary origins of selected AMP families and to identify evolutionarily conserved and taxon-specific families. Furthermore, we highlight the use of the nematode Caenorhabditis elegans as a whole-animal model in high-throughput screening methods to identify AMPs with efficacy against human pathogens, including Acinetobacter baumanii and methicillin-resistant Staphylococcus aureus We also discuss the potential medical applications of AMPs, including their use as alternatives for conventional antibiotics in ectopic therapies, their combined use with antibiotics to restore the susceptibility of multidrug-resistant pathogens, and their use as templates for the rational design of peptidomimetic drugs that overcome the disadvantages of therapeutic peptides.The article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160593

  9. Diversity, evolution and medical applications of insect antimicrobial peptides

    PubMed Central

    Mylonakis, Eleftherios; Podsiadlowski, Lars; Muhammed, Maged

    2016-01-01

    Antimicrobial peptides (AMPs) are short proteins with antimicrobial activity. A large portion of known AMPs originate from insects, and the number and diversity of these molecules in different species varies considerably. Insect AMPs represent a potential source of alternative antibiotics to address the limitation of current antibiotics, which has been caused by the emergence and spread of multidrug-resistant pathogens. To get more insight into AMPs, we investigated the diversity and evolution of insect AMPs by mapping their phylogenetic distribution, allowing us to predict the evolutionary origins of selected AMP families and to identify evolutionarily conserved and taxon-specific families. Furthermore, we highlight the use of the nematode Caenorhabditis elegans as a whole-animal model in high-throughput screening methods to identify AMPs with efficacy against human pathogens, including Acinetobacter baumanii and methicillin-resistant Staphylococcus aureus. We also discuss the potential medical applications of AMPs, including their use as alternatives for conventional antibiotics in ectopic therapies, their combined use with antibiotics to restore the susceptibility of multidrug-resistant pathogens, and their use as templates for the rational design of peptidomimetic drugs that overcome the disadvantages of therapeutic peptides. The article is part of the themed issue ‘Evolutionary ecology of arthropod antimicrobial peptides’. PMID:27160593

  10. Transmission of bacterial plant pathogens by Hemipteran vectors: The intersection of genomics and classical vector biology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insects that are classified in the Order Hemiptera have become one of the most important plant-associated insect taxa, mainly because of their ability to transmit plant pathogens. The glassy-winged sharpshooter is the primary vector of the plant-infecting bacterium Xylella fastidiosa, the causal age...

  11. Environmental RNAi in herbivorous insects

    PubMed Central

    Ivashuta, Sergey; Zhang, Yuanji; Wiggins, B. Elizabeth; Ramaseshadri, Partha; Segers, Gerrit C.; Johnson, Steven; Meyer, Steve E.; Kerstetter, Randy A.; McNulty, Brian C.; Bolognesi, Renata; Heck, Gregory R.

    2015-01-01

    Environmental RNAi (eRNAi) is a sequence-specific regulation of endogenous gene expression in a receptive organism by exogenous double-stranded RNA (dsRNA). Although demonstrated under artificial dietary conditions and via transgenic plant presentations in several herbivorous insects, the magnitude and consequence of exogenous dsRNA uptake and the role of eRNAi remains unknown under natural insect living conditions. Our analysis of coleopteran insects sensitive to eRNAi fed on wild-type plants revealed uptake of plant endogenous long dsRNAs, but not small RNAs. Subsequently, the dsRNAs were processed into 21 nt siRNAs by insects and accumulated in high quantities in insect cells. No accumulation of host plant-derived siRNAs was observed in lepidopteran larvae that are recalcitrant to eRNAi. Stability of ingested dsRNA in coleopteran larval gut followed by uptake and transport from the gut to distal tissues appeared to be enabling factors for eRNAi. Although a relatively large number of distinct coleopteran insect-processed plant-derived siRNAs had sequence complementarity to insect transcripts, the vast majority of the siRNAs were present in relatively low abundance, and RNA-seq analysis did not detect a significant effect of plant-derived siRNAs on insect transcriptome. In summary, we observed a broad genome-wide uptake of plant endogenous dsRNA and subsequent processing of ingested dsRNA into 21 nt siRNAs in eRNAi-sensitive insects under natural feeding conditions. In addition to dsRNA stability in gut lumen and uptake, dosage of siRNAs targeting a given insect transcript is likely an important factor in order to achieve measurable eRNAi-based regulation in eRNAi-competent insects that lack an apparent silencing amplification mechanism. PMID:25802407

  12. Paleozoic origin of insect large dsDNA viruses.

    PubMed

    Thézé, Julien; Bézier, Annie; Periquet, Georges; Drezen, Jean-Michel; Herniou, Elisabeth A

    2011-09-20

    To understand how extant viruses interact with their hosts, we need a historical framework of their evolutionary association. Akin to retrovirus or hepadnavirus viral fossils present in eukaryotic genomes, bracoviruses are integrated in braconid wasp genomes and are transmitted by Mendelian inheritance. However, unlike viral genomic fossils, they have retained functional machineries homologous to those of large dsDNA viruses pathogenic to arthropods. Using a phylogenomic approach, we resolved the relationships between bracoviruses and their closest free relatives: baculoviruses and nudiviruses. The phylogeny showed that bracoviruses are nested within the nudivirus clade. Bracoviruses establish a bridge between the virus and animal worlds. Their inclusion in a virus phylogeny allowed us to relate free viruses to fossils. The ages of the wasps were used to calibrate the virus phylogeny. Bayesian analyses revealed that insect dsDNA viruses first evolved at ∼310 Mya in the Paleozoic Era during the Carboniferous Period with the first insects. Furthermore the virus diversification time frame during the Mesozoic Era appears linked to the diversification of insect orders; baculoviruses that infect larvae evolved at the same period as holometabolous insects. These results imply ancient coevolution by resource tracking between several insect dsDNA virus families and their hosts, dating back to 310 Mya. PMID:21911395

  13. Aquatic Insects as a Vector for Mycobacterium ulcerans

    PubMed Central

    Marsollier, Laurent; Robert, Raymond; Aubry, Jacques; André, Jean-Paul Saint; Kouakou, Henri; Legras, Pierre; Manceau, Anne-Lise; Mahaza, Chetaou; Carbonnelle, Bernard

    2002-01-01

    Mycobacterium ulcerans is an emerging environmental pathogen which causes chronic skin ulcers (i.e., Buruli ulcer) in otherwise healthy humans living in tropical countries, particularly those in Africa. In spite of epidemiological and PCR data linking M. ulcerans to water, the mode of transmission of this organism remains elusive. To determine the role of aquatic insects in the transmission of M. ulcerans, we have set up an experimental model with aquariums that mimic aquatic microenvironments. We report that M. ulcerans may be transmitted to laboratory mice by the bite of aquatic bugs (Naucoridae) that are infected with this organism. In addition, M. ulcerans appears to be localized exclusively within salivary glands of these insects, where it can both survive and multiply without causing any observable damage in the insect tissues. Subsequently, we isolated M. ulcerans from wild aquatic insects collected from a zone in the Daloa region of Ivory Coast where Buruli ulcer is endemic. Taken together, these results point to aquatic insects as a possible vector of M. ulcerans. PMID:12200321

  14. Aquatic insects as a vector for Mycobacterium ulcerans.

    PubMed

    Marsollier, Laurent; Robert, Raymond; Aubry, Jacques; Saint André, Jean-Paul; Kouakou, Henri; Legras, Pierre; Manceau, Anne-Lise; Mahaza, Chetaou; Carbonnelle, Bernard

    2002-09-01

    Mycobacterium ulcerans is an emerging environmental pathogen which causes chronic skin ulcers (i.e., Buruli ulcer) in otherwise healthy humans living in tropical countries, particularly those in Africa. In spite of epidemiological and PCR data linking M. ulcerans to water, the mode of transmission of this organism remains elusive. To determine the role of aquatic insects in the transmission of M. ulcerans, we have set up an experimental model with aquariums that mimic aquatic microenvironments. We report that M. ulcerans may be transmitted to laboratory mice by the bite of aquatic bugs (Naucoridae) that are infected with this organism. In addition, M. ulcerans appears to be localized exclusively within salivary glands of these insects, where it can both survive and multiply without causing any observable damage in the insect tissues. Subsequently, we isolated M. ulcerans from wild aquatic insects collected from a zone in the Daloa region of Ivory Coast where Buruli ulcer is endemic. Taken together, these results point to aquatic insects as a possible vector of M. ulcerans. PMID:12200321

  15. Intervention of Phytohormone Pathways by Pathogen Effectors[OPEN

    PubMed Central

    Kazan, Kemal; Lyons, Rebecca

    2014-01-01

    The constant struggle between plants and microbes has driven the evolution of multiple defense strategies in the host as well as offense strategies in the pathogen. To defend themselves from pathogen attack, plants often rely on elaborate signaling networks regulated by phytohormones. In turn, pathogens have adopted innovative strategies to manipulate phytohormone-regulated defenses. Tactics frequently employed by plant pathogens involve hijacking, evading, or disrupting hormone signaling pathways and/or crosstalk. As reviewed here, this is achieved mechanistically via pathogen-derived molecules known as effectors, which target phytohormone receptors, transcriptional activators and repressors, and other components of phytohormone signaling in the host plant. Herbivores and sap-sucking insects employ obligate pathogens such as viruses, phytoplasma, or symbiotic bacteria to intervene with phytohormone-regulated defenses. Overall, an improved understanding of phytohormone intervention strategies employed by pests and pathogens during their interactions with plants will ultimately lead to the development of new crop protection strategies. PMID:24920334

  16. Management of plant pathogens and pests using microbial biological control agents. In: Trigiano, R.N. and Ownley, B.H., editors. Plant Pathology Concepts and Laboratory Exercises

    Technology Transfer Automated Retrieval System (TEKTRAN)

    All parts of plants face continual attack by plant pathogens and insects. Some insects are vectors of pathogens. Plant pests can be controlled by a variety of methods including application of pesticides but one of the most stainable and environmentally friendly approaches is biological control. Mic...

  17. Plant Defense against Insect Herbivores

    PubMed Central

    Fürstenberg-Hägg, Joel; Zagrobelny, Mika; Bak, Søren

    2013-01-01

    Plants have been interacting with insects for several hundred million years, leading to complex defense approaches against various insect feeding strategies. Some defenses are constitutive while others are induced, although the insecticidal defense compound or protein classes are often similar. Insect herbivory induce several internal signals from the wounded tissues, including calcium ion fluxes, phosphorylation cascades and systemic- and jasmonate signaling. These are perceived in undamaged tissues, which thereafter reinforce their defense by producing different, mostly low molecular weight, defense compounds. These bioactive specialized plant defense compounds may repel or intoxicate insects, while defense proteins often interfere with their digestion. Volatiles are released upon herbivory to repel herbivores, attract predators or for communication between leaves or plants, and to induce defense responses. Plants also apply morphological features like waxes, trichomes and latices to make the feeding more difficult for the insects. Extrafloral nectar, food bodies and nesting or refuge sites are produced to accommodate and feed the predators of the herbivores. Meanwhile, herbivorous insects have adapted to resist plant defenses, and in some cases even sequester the compounds and reuse them in their own defense. Both plant defense and insect adaptation involve metabolic costs, so most plant-insect interactions reach a stand-off, where both host and herbivore survive although their development is suboptimal. PMID:23681010

  18. Polarization Imaging and Insect Vision

    ERIC Educational Resources Information Center

    Green, Adam S.; Ohmann, Paul R.; Leininger, Nick E.; Kavanaugh, James A.

    2010-01-01

    For several years we have included discussions about insect vision in the optics units of our introductory physics courses. This topic is a natural extension of demonstrations involving Brewster's reflection and Rayleigh scattering of polarized light because many insects heavily rely on optical polarization for navigation and communication.…

  19. Reader Survey for INSECT ALERTS.

    ERIC Educational Resources Information Center

    Miller, Mason E.; Sauer, Richard J.

    To determine what might be done to improve "Insect Alerts," which is a newsletter that carries "information on insect biology, abundance, activity and interpretation of control need," put out through the Michigan Cooperative Extension Service 26 weeks a year, a survey was conducted. A mail questionnaire was sent to all 120 county extension…

  20. RNAI: Future in insect management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    RNA interference is a post-transcriptional, gene regulation mechanism found in virtually all plants and animals including insects. The demonstration of RNAi in insects and its successful use as a tool in the study of functional genomics opened the door to the development of a variety of novel, envir...

  1. Chickpea Ascochyta blight and insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early symptoms of Acochyta blight and insect damages were detected in the Paliuse region.This article informs chickpea scientists and growers about current disease and insect pest problems in the Palouse region. Ascochyta blight appeared in many chickpea fields and was severe in some fields. Insec...

  2. A Template for Insect Cryopreservation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article is intended to update the reader on the progress made on insect embryo cryopreservation in the past 20 years and gives information for developing a protocol for cryopreserving insects by using a 2001 study as a template. The study used for the template is the cryopreservation of the Old...

  3. Eicosanoids mediate insect hemocyte migration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hemocyte chemotaxis toward infection and wound sites is an essential component of insect defense reactions, although the biochemical signal mechanisms responsible for mediating chemotaxis in insect cells are not well understood. Here we report on the outcomes of experiments designed to test the hyp...

  4. Effects of destruxins on free calcium and hydrogen ions in insect hemocytes.

    PubMed

    Chen, Xiu-Run; Hu, Qiong-Bo; Yu, Xiao-Qiang; Ren, Shun-Xiang

    2014-02-01

    Destruxins, cyclohexadepsipeptidic mycotoxins isolated from the entomopathogenic fungus Metarhizium anisopliae, inhibit innate insect immunity. However, their mechanism of action remains unclear. In this study, the effects of destruxins on changes in free calcium and hydrogen ions in the hemocytes of Exolontha serrulata, Bombyx mori and the Spodoptera litura SL-1 cell line were detected using laser scanning confocal microscopy (LSCM). An instant Ca(2+) influx of hemocytes induced by destruxins A and B (DA and DB) was recorded. The DA/DB-dependent Ca(2+) influx was not influenced by the Ca(2+) channel inhibitors 2-aminoethoxydiphenyl borane (2-APB) and U73122. It also had an apparently different LSCM profile from that of the ionomycin-dependent Ca(2+) influx. However, the instant Ca(2+) influx was not seen in the SL-1 cells; on the contrary, a slow, moderate enhancement of intracellular Ca(2+) was observed. Meanwhile, an instant intracellular free H(+) decrease aroused by DA and DB was found. DB at 20 μmol/L and DA at 690 μmol/L significantly reduced intracellular free H(+) levels. Furthermore, the vacuolar H(+)-ATPase (V-ATPase) inhibitor bafilomycin A1 had obvious effects on the decreases of intracellular free H(+) in hemocytes. These results suggest that the mechanism of DA/DB-dependent Ca(2+) influx is perhaps not related to Ca(2+) channels and ionophores; rather, the intracellular free H(+) decrease might be due to V-ATPase inhibition. PMID:23956215

  5. Population fluctuation in phytophagous insects

    SciTech Connect

    Redfearn, A.; Pimm, S.L. )

    1994-06-01

    We examined how community interactions affect year-to-year population variability in three groups of phytophagous insects: British aphids and moths, and Canadian moths. We first examined how the number of host plant species on which a given phytophagous insect species feeds affects its population variability. Specialist insect species showed a weak tendency to be more variable than generalist species. We then examined how the number of species of parasitoids from which a given phytophagous insects species suffers affects its population variability. Species that are host to few parasitoid species showed a weak tendency to be more variable than species with many parsitoid species. These relationships also depend on other aspects of the life histories of the phytophagous insect species.

  6. The aerodynamics of insect flight.

    PubMed

    Sane, Sanjay P

    2003-12-01

    The flight of insects has fascinated physicists and biologists for more than a century. Yet, until recently, researchers were unable to rigorously quantify the complex wing motions of flapping insects or measure the forces and flows around their wings. However, recent developments in high-speed videography and tools for computational and mechanical modeling have allowed researchers to make rapid progress in advancing our understanding of insect flight. These mechanical and computational fluid dynamic models, combined with modern flow visualization techniques, have revealed that the fluid dynamic phenomena underlying flapping flight are different from those of non-flapping, 2-D wings on which most previous models were based. In particular, even at high angles of attack, a prominent leading edge vortex remains stably attached on the insect wing and does not shed into an unsteady wake, as would be expected from non-flapping 2-D wings. Its presence greatly enhances the forces generated by the wing, thus enabling insects to hover or maneuver. In addition, flight forces are further enhanced by other mechanisms acting during changes in angle of attack, especially at stroke reversal, the mutual interaction of the two wings at dorsal stroke reversal or wing-wake interactions following stroke reversal. This progress has enabled the development of simple analytical and empirical models that allow us to calculate the instantaneous forces on flapping insect wings more accurately than was previously possible. It also promises to foster new and exciting multi-disciplinary collaborations between physicists who seek to explain the phenomenology, biologists who seek to understand its relevance to insect physiology and evolution, and engineers who are inspired to build micro-robotic insects using these principles. This review covers the basic physical principles underlying flapping flight in insects, results of recent experiments concerning the aerodynamics of insect flight, as well

  7. Peripheral olfactory signaling in insects

    PubMed Central

    Suh, Eunho; Bohbot, Jonathan; Zwiebel, Laurence J.

    2014-01-01

    Olfactory signaling is a crucial component in the life history of insects. The development of precise and parallel mechanisms to analyze the tremendous amount of chemical information from the environment and other sources has been essential to their evolutionary success. Considerable progress has been made in the study of insect olfaction fueled by bioinformatics- based utilization of genomics along with rapid advances in functional analyses. Here we review recent progress in our rapidly emerging understanding of insect peripheral sensory reception and signal transduction. These studies reveal that the nearly unlimited chemical space insects encounter is covered by distinct chemosensory receptor repertoires that are generally derived by species-specific, rapid gene gain and loss, reflecting the evolutionary consequences of adaptation to meet their specific biological needs. While diverse molecular mechanisms have been put forth, often in the context of controversial models, the characterization of the ubiquitous, highly conserved and insect-specific Orco odorant receptor co-receptor has opened the door to the design and development of novel insect control methods to target agricultural pests, disease vectors and even nuisance insects. PMID:25584200

  8. Intracellular siderophore but not extracellular siderophore is required for full virulence in Metarhizium robertsii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Efficient iron acquisition mechanisms are fundamental for microbial survival in the environment and for pathogen virulence within their hosts. M. robertsii produces two known iron-binding natural products: metachelins, which are used to scavenge extracellular iron, and ferricrocin, which is strictly...

  9. Entomopathogenic Fungi: New Insights into Host-Pathogen Interactions.

    PubMed

    Butt, T M; Coates, C J; Dubovskiy, I M; Ratcliffe, N A

    2016-01-01

    Although many insects successfully live in dangerous environments exposed to diverse communities of microbes, they are often exploited and killed by specialist pathogens. Studies of host-pathogen interactions (HPI) provide valuable insights into the dynamics of the highly aggressive coevolutionary arms race between entomopathogenic fungi (EPF) and their arthropod hosts. The host defenses are designed to exclude the pathogen or mitigate the damage inflicted while the pathogen responds with immune evasion and utilization of host resources. EPF neutralize their immediate surroundings on the insect integument and benefit from the physiochemical properties of the cuticle and its compounds that exclude competing microbes. EPF also exhibit adaptations aimed at minimizing trauma that can be deleterious to both host and pathogen (eg, melanization of hemolymph), form narrow penetration pegs that alleviate host dehydration and produce blastospores that lack immunogenic sugars/enzymes but facilitate rapid assimilation of hemolymph nutrients. In response, insects deploy an extensive armory of hemocytes and macromolecules, such as lectins and phenoloxidase, that repel, immobilize, and kill EPF. New evidence suggests that immune bioactives work synergistically (eg, lysozyme with antimicrobial peptides) to combat infections. Some proteins, including transferrin and apolipophorin III, also demonstrate multifunctional properties, participating in metabolism, homeostasis, and pathogen recognition. This review discusses the molecular intricacies of these HPI, highlighting the interplay between immunity, stress management, and metabolism. Increased knowledge in this area could enhance the efficacy of EPF, ensuring their future in integrated pest management programs. PMID:27131329

  10. Formation of disulfide bonds in insect prophenoloxidase enhances immunity through improving enzyme activity and stability.

    PubMed

    Lu, Anrui; Peng, Qin; Ling, Erjun

    2014-06-01

    Type 3 copper proteins, including insect prophenoloxidase (PPO), contain two copper atoms in the active site pocket and can oxidize phenols. Insect PPO plays an important role in immunity. Insects and other invertebrates show limited recovery from pathogen invasion and wounds if phenoloxidase (PO) activity is low. In most insect PPOs, two disulfide bonds are present near the C-terminus. However, in Pimpla hypochondriaca (a parasitoid wasp), each PPO contains one disulfide bond. We thus questioned whether the formation of two sulfide bonds in insect PPOs improved protein stability and/or increased insect innate immunity over time. Using Drosophila melanogaster PPO1 as a model, one or two disulfide bonds were deleted to evaluate the importance of disulfide bonds in insect immunity. rPPO1 and mutants lacking disulfide bonds could be expressed and showed PO activity. However, the PO activities of mutants lacking one or two disulfide bonds significantly decreased. Deletion of disulfide bonds also reduced PPO thermostability. Furthermore, antibacterial activities against Escherichia coli and Bacillus subtilis significantly decreased when disulfide bonds were deleted. Therefore, the formation of two disulfide bond(s) in insect PPO enhances antibacterial activity by increasing PO activity and stability. PMID:24480295

  11. Integrated Immune and Cardiovascular Function in Pancrustacea: Lessons from the Insects.

    PubMed

    Hillyer, Julián F

    2015-11-01

    When pathogens invade the insect hemocoel (body cavity) they immediately confront two major forces: immune-responses and circulatory currents. The immune response is mediated by circulating and sessile hemocytes, the fat body, the midgut, and the salivary glands. These tissues drive cellular and humoral immune processes that kill pathogens via phagocytosis, melanization, lysis, encapsulation, and nodulation. Moreover, immune-responses take place within a three-dimensional and dynamic space that is governed by the forces of the circulatory system. The circulation of hemolymph (insect blood) is primarily controlled by the wave-like contraction of a dorsal vessel, which is a muscular tube that extends the length of the insect and is divided into a thoracic aorta and an abdominal heart. Distributed along the heart are valves, called ostia, that allow hemolymph to enter the vessel. Once inside the heart, hemolymph is sequentially propelled to the anterior and to the posterior of the body. During an infection, circulatory currents sweep small pathogens to all regions of the body. As they circulate, pathogens encounter immune factors of the insect that range from soluble cytotoxic peptides to phagocytic hemocytes. A prominent location for these encounters is the surface of the heart. Specifically, periostial hemocytes aggregate in the extracardiac regions that flank the heart's ostia (the periostial regions) and phagocytoze pathogens in areas of high flow of hemolymph. This review summarizes the biology of the immune and circulatory systems of insects, including how these two systems have co-adapted to fight infection. This review also compares the immune and circulatory systems of insects to that of crustaceans, and details how attachment of hemocytes to cardiac tissues and the biology of the lymphoid organ demonstrate that dynamic interactions between the immune and circulatory systems also occur in lineages of crustaceans. PMID:25898841

  12. Entomopathogenic nematodes and insect management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Entomopathogenic nematodes (genera Heterorhabditis, Steinernema, and Neosteinernema) are used as bioinsecticides. The nematodes are ubiquitous and have been isolated in soil of every continent except Antarctica. The nematodes kill insects through a mutualism with a bacterium (Photorhabdus spp. or ...

  13. Insect symbionts in food webs

    PubMed Central

    Henry, Lee M.

    2016-01-01

    Recent research has shown that the bacterial endosymbionts of insects are abundant and diverse, and that they have numerous different effects on their hosts' biology. Here we explore how insect endosymbionts might affect the structure and dynamics of insect communities. Using the obligate and facultative symbionts of aphids as an example, we find that there are multiple ways that symbiont presence might affect food web structure. Many symbionts are now known to help their hosts escape or resist natural enemy attack, and others can allow their hosts to withstand abiotic stress or affect host plant use. In addition to the direct effect of symbionts on aphid phenotypes there may be indirect effects mediated through trophic and non-trophic community interactions. We believe that by using data from barcoding studies to identify bacterial symbionts, this extra, microbial dimension to insect food webs can be better elucidated. This article is part of the themed issue ‘From DNA barcodes to biomes’. PMID:27481779

  14. Insect symbionts in food webs.

    PubMed

    McLean, Ailsa H C; Parker, Benjamin J; Hrček, Jan; Henry, Lee M; Godfray, H Charles J

    2016-09-01

    Recent research has shown that the bacterial endosymbionts of insects are abundant and diverse, and that they have numerous different effects on their hosts' biology. Here we explore how insect endosymbionts might affect the structure and dynamics of insect communities. Using the obligate and facultative symbionts of aphids as an example, we find that there are multiple ways that symbiont presence might affect food web structure. Many symbionts are now known to help their hosts escape or resist natural enemy attack, and others can allow their hosts to withstand abiotic stress or affect host plant use. In addition to the direct effect of symbionts on aphid phenotypes there may be indirect effects mediated through trophic and non-trophic community interactions. We believe that by using data from barcoding studies to identify bacterial symbionts, this extra, microbial dimension to insect food webs can be better elucidated.This article is part of the themed issue 'From DNA barcodes to biomes'. PMID:27481779

  15. Eicosanoid actions in insect immunology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this chapter we review eicosanoid actions in insect immunity. Eicosanoids are oxygenated metabolites of arachidonic acid (AA) and two other C20 polyunsaturated polyunsaturated fatty acids. Groups of eicosanoids include prostaglandins, lipoxygenase products and epoxyeicosatrienoic acids. These ...

  16. Radar Observation of Insects - Mosquitoes

    NASA Technical Reports Server (NTRS)

    Frost, E.; Downing, J.

    1979-01-01

    Tests were conducted at several sites over the coastal lowlands of New Jersey and over a region of high plains and low mountains in Oklahoma. In one area, a salt marsh in New Jersey, extensive ground tests were combined with laboratory data on expected insect backscatter to arrive at an extremely convincing model of the insect origin of most Dot Angels. A great deal of insight was studied from radar on the buildup and dispersal of insect swarms, since radar can follow where other means of trapping and observation cannot. Data on large-scale behavior as a function of wind and topography are presented. Displayed techniques which show individual or small swarm motion within some larger cloud or mass, or which can show the overall motion over great distances were developed. The influence of wind and terrain on insect motion and dispersal is determined from radar data.

  17. Freshwater Biodiversity and Insect Diversification

    PubMed Central

    Dijkstra, Klaas-Douwe B.; Monaghan, Michael T.; Pauls, Steffen U.

    2016-01-01

    Inland waters cover less than one percent of Earth’s surface, but harbor more than six percent of all insect species: nearly 100,000 species from 12 orders spend one or more life stages in freshwater. Little is known about how this remarkable diversity arose, although allopatric speciation and ecological adaptation are thought to be primary mechanisms. Freshwater habitats are exceptionally susceptible to environmental change, and exhibit marked ecological gradients. The amphibiotic lifestyles of aquatic insects result in complex contributions of extinction and allopatric and non-allopatric speciation in species diversification. In contrast to the lack of evolutionary studies, the ecology and habitat preferences of aquatic insects have been intensively studied, in part because of their widespread use as bio-indicators. The combination of phylogenetics with the extensive ecological data provides a promising avenue for future research, making aquatic insects highly suitable models for the study of ecological diversification. PMID:24160433

  18. Flight of the smallest insects

    NASA Astrophysics Data System (ADS)

    Miller, Laura; Santhanakrishnan, Arvind; Hedrick, Tyson; Robinson, Alice

    2009-11-01

    A vast body of research has described the complexity of flight in insects ranging from the fruit fly, Drosophila melanogaster, to the hawk moth, Manduca sexta. Over this range of scales, flight aerodynamics as well as the relative lift and drag forces generated are surprisingly similar. The smallest flying insects (Re˜10) have received far less attention, although previous work has shown that flight kinematics and aerodynamics can be significantly different. In this presentation, we have used a three-pronged approach that consists of measurements of flight kinematics in the tiny insect Thysanoptera (thrips), measurements of flow velocities using physical models, and direct numerical simulations to compute lift and drag forces. We find that drag forces can be an order of magnitude larger than lift forces, particularly during the clap and fling motion used by all tiny insects recorded to date.

  19. Insect bites and stings (image)

    MedlinePlus

    Even though some insect bites or stings can be extremely painful they usually do not require emergency medical care. Although the stung or bitten area should be carefully observed for signs of infection or reaction to venom.

  20. Fungal entomopathogens with activity against plant pathogens: ecology and evolution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dual biological control, of both insect pests and plant pathogens, has been reported for the entomopathogenic fungi Beauveria bassiana and Lecanicillium spp. However, the primary mechanisms of plant disease suppression are different for these fungi. Beauveria produces an array of bioactive metabolit...

  1. Manipulation of arthropod pathogens for integrated pest management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A great diversity of pathogenic microorganisms and nematodes has been developed for microbial biological control of insect and other arthropod pests. These control agents have many characteristics that determine their capacities to provide reliable pest control, and these characteristics must be ta...

  2. Preface: Insect Pathology, 2nd ed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect pathology is an essential component of entomology and provides a non-chemical alternative for insect pest management. There are several groups of organisms that can infect and kill insects including viruses, fungi, microsporidia, bacteria, protists, and nematodes. The dilemma in insect patho...

  3. Pollen Recovery from Insects: Light Microscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous insect species feed on the pollen, nectar, and other plant exudates that are associated with flowers. As a result of this feeding activity, pollen becomes attached to the insects. Analysis of the pollen attached to these insects can reveal what insects eat, their dispersal patterns in and...

  4. 7 CFR 51.2290 - Insect injury.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Insect injury. 51.2290 Section 51.2290 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.2290 Insect injury. Insect injury means that the insect, web, frass or other evidence of...

  5. How Do Insects Help the Environment?

    ERIC Educational Resources Information Center

    Hevel, Gary

    2005-01-01

    There are some 5 to 30 million insect species estimated in the world--and the majority of these have yet to be collected or named by science! Of course, the most well known insects are those that cause disease or compete for human agricultural products, but these insects represent only a small fraction of the world's insect population. In reality,…

  6. 46 CFR 108.215 - Insect screens.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Insect screens. 108.215 Section 108.215 Shipping COAST... Construction and Arrangement Accommodation Spaces § 108.215 Insect screens. (a) Accommodation spaces must be protected against the admission of insects. (b) Insect screens must be installed when natural ventilation...

  7. 7 CFR 51.2122 - Insect injury.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Insect injury. 51.2122 Section 51.2122 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Shelled Almonds Definitions § 51.2122 Insect injury. Insect injury means that the insect, web, or frass is present or there is definite evidence...

  8. 7 CFR 51.2122 - Insect injury.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Insect injury. 51.2122 Section 51.2122 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Shelled Almonds Definitions § 51.2122 Insect injury. Insect injury means that the insect, web, or frass is present or there is definite evidence...

  9. 7 CFR 51.2290 - Insect injury.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Insect injury. 51.2290 Section 51.2290 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.2290 Insect injury. Insect injury means that the insect, web, frass or other evidence of...

  10. 46 CFR 108.215 - Insect screens.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Insect screens. 108.215 Section 108.215 Shipping COAST... Construction and Arrangement Accommodation Spaces § 108.215 Insect screens. (a) Accommodation spaces must be protected against the admission of insects. (b) Insect screens must be installed when natural ventilation...

  11. 7 CFR 51.2008 - Insect injury.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Insect injury. 51.2008 Section 51.2008 Agriculture... Standards for Grades of Filberts in the Shell 1 Definitions § 51.2008 Insect injury. Insect injury means that the insect, frass or web is present inside the nut or the kernel shows definite evidence of...

  12. 46 CFR 108.215 - Insect screens.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Insect screens. 108.215 Section 108.215 Shipping COAST... Construction and Arrangement Accommodation Spaces § 108.215 Insect screens. (a) Accommodation spaces must be protected against the admission of insects. (b) Insect screens must be installed when natural ventilation...

  13. 46 CFR 108.215 - Insect screens.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Insect screens. 108.215 Section 108.215 Shipping COAST... Construction and Arrangement Accommodation Spaces § 108.215 Insect screens. (a) Accommodation spaces must be protected against the admission of insects. (b) Insect screens must be installed when natural ventilation...

  14. 46 CFR 108.215 - Insect screens.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Insect screens. 108.215 Section 108.215 Shipping COAST... Construction and Arrangement Accommodation Spaces § 108.215 Insect screens. (a) Accommodation spaces must be protected against the admission of insects. (b) Insect screens must be installed when natural ventilation...

  15. 7 CFR 51.2008 - Insect injury.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Insect injury. 51.2008 Section 51.2008 Agriculture... Standards for Grades of Filberts in the Shell 1 Definitions § 51.2008 Insect injury. Insect injury means that the insect, frass or web is present inside the nut or the kernel shows definite evidence of...

  16. 7 CFR 51.2008 - Insect injury.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Insect injury. 51.2008 Section 51.2008 Agriculture... Standards for Grades of Filberts in the Shell 1 Definitions § 51.2008 Insect injury. Insect injury means that the insect, frass or web is present inside the nut or the kernel shows definite evidence of...

  17. Don't Let Insects Bug You!

    ERIC Educational Resources Information Center

    Abraham, Doc; Abraham, Katy

    1977-01-01

    Are you one of those people who feel that the only good insect is a dead one? Do you suffer from entomophobia--dread fear of insects? Such attitudes, fears, and prejudices stem from insect ignorance. Authors explain what insects are good for and give students a more realistic and fascinating view of their world. (Editor/RK)

  18. Pathogene Mikroorganismen

    NASA Astrophysics Data System (ADS)

    Wagner, Martin

    Infektionen, die vom Tier auf den Menschen übertragen werden, werden als Zoonosen bezeichnet. Pathogene Mikroorganismen können entweder durch Mensch-Mensch, Mensch-Tier-Kontakt oder durch Kontakt mit kontaminierten Vektoren übertragen werden [39]. Vektoren können einerseits belebt (z. B. blutsaugende Insekten), andererseits unbelebt sein. Kontaminierte Lebensmittel und Wasser gehören zu den wichtigsten unbelebten Vektoren. Neben Lebensmitteln können aber auch kontaminierte Gegenstände oder der Kontakt mit Kontaminationsquellen in der Umwelt Auslöser von Krankheitsfällen sein. Weltweit sind mehr als 1400 krankheitsverursachende biologische Agentien bekannt, von denen über 60 % ein zoonotisches Potenzial aufweisen. Als Ergebnis von Expertengesprächen wurde kürzlich berichtet, dass etwa 3 bis 4, meist virale, neu auftretende Infektionskrankheiten ("emerging diseases“) pro Jahr erwartet werden können [15]. Es handelt sich bei diesen Vorgängen aber nicht nur um das Auftauchen vollkommen neuer oder unbeschriebener Spezies, sondern auch um evolutionsbedingte Anpassungen von mikrobiellen Populationen an neue Bedingungen in ihrem Ökosystem [7]. Molekulare Analysen an Umweltchlamydien erbrachten Hinweise, dass die Evolution erste genetische Pathogenitätsmerkmale in dieser Spezies schon vor 700 Mio. Jahren entstehen ließ [14]. Viele Faktoren befeuern den Prozess der Anpassung, unter anderem auch alle Strategien, mit denen der Mensch seit Jahrtausenden versucht, Lebensmittel sicher und haltbar zu machen. Als die treibenden Kräfte des Auftretens neuer Krankheitserreger werden in der Gegenwart vor allem das sich ändernde Weltklima, die globalen Warenströme und die sich verändernden Konsumgewohnheiten genannt. Es steht auch außer Zweifel, dass viele dieser Erreger Tiere als ihr natürliches Reservoir haben werden, d. h. Zoonosen im klassischen Sinne sind [15].

  19. Fungal biosynthesis of the bibenzoquinone oosporein to evade insect immunity

    PubMed Central

    Feng, Peng; Shang, Yanfang; Cen, Kai; Wang, Chengshu

    2015-01-01

    Quinones are widely distributed in nature and exhibit diverse biological or pharmacological activities; however, their biosynthetic machineries are largely unknown. The bibenzoquinone oosporein was first identified from the ascomycete insect pathogen Beauveria bassiana >50 y ago. The toxin can also be produced by different plant pathogenic and endophytic fungi with an array of biological activities. Here, we report the oosporein biosynthetic machinery in fungi, a polyketide synthase (PKS) pathway including seven genes for quinone biosynthesis. The PKS oosporein synthase 1 (OpS1) produces orsellinic acid that is hydroxylated to benzenetriol by the hydroxylase OpS4. The intermediate is oxidized either nonenzymatically to 5,5′-dideoxy-oosporein or enzymatically to benzenetetrol by the putative dioxygenase OpS7. The latter is further dimerized to oosporein by the catalase OpS5. The transcription factor OpS3 regulates intrapathway gene expression. Insect bioassays revealed that oosporein is required for fungal virulence and acts by evading host immunity to facilitate fungal multiplication in insects. These results contribute to the known mechanisms of quinone biosynthesis and the understanding of small molecules deployed by fungi that interact with their hosts. PMID:26305932

  20. Fungal biosynthesis of the bibenzoquinone oosporein to evade insect immunity.

    PubMed

    Feng, Peng; Shang, Yanfang; Cen, Kai; Wang, Chengshu

    2015-09-01

    Quinones are widely distributed in nature and exhibit diverse biological or pharmacological activities; however, their biosynthetic machineries are largely unknown. The bibenzoquinone oosporein was first identified from the ascomycete insect pathogen Beauveria bassiana>50 y ago. The toxin can also be produced by different plant pathogenic and endophytic fungi with an array of biological activities. Here, we report the oosporein biosynthetic machinery in fungi, a polyketide synthase (PKS) pathway including seven genes for quinone biosynthesis. The PKS oosporein synthase 1 (OpS1) produces orsellinic acid that is hydroxylated to benzenetriol by the hydroxylase OpS4. The intermediate is oxidized either nonenzymatically to 5,5'-dideoxy-oosporein or enzymatically to benzenetetrol by the putative dioxygenase OpS7. The latter is further dimerized to oosporein by the catalase OpS5. The transcription factor OpS3 regulates intrapathway gene expression. Insect bioassays revealed that oosporein is required for fungal virulence and acts by evading host immunity to facilitate fungal multiplication in insects. These results contribute to the known mechanisms of quinone biosynthesis and the understanding of small molecules deployed by fungi that interact with their hosts. PMID:26305932