Nitrogen Supply Influences Herbivore-Induced Direct and Indirect Defenses and Transcriptional Responses in Nicotiana attenuata[w

PubMed Central

Lou, Yonggen; Baldwin, Ian T.

2004-01-01

Although nitrogen (N) availability is known to alter constitutive resistance against herbivores, its influence on herbivore-induced responses, including signaling pathways, transcriptional signatures, and the subsequently elicited chemical defenses is poorly understood. We used the native tobacco, Nicotiana attenuata, which germinates in the postfire environment and copes with large changes in soil N during postfire succession, to compare a suite of Manduca sexta- and elicitor-induced responses in plants grown under high- and low-N (LN) supply rates. LN supply decreased relative growth rates and biomass by 35% at 40 d compared to high-N plants; furthermore, it also attenuated (by 39 and 60%) the elicitor-induced jasmonate and salicylate bursts, two N-intensive direct defenses (nicotine and trypsin proteinase inhibitors, albeit by different mechanisms), and carbon-containing nonvolatile defenses (rutin, chlorogenic acid, and diterpene glycosides), but did not affect the induced release of volatiles (cis-α-bergamotene and germacrene A), which function as indirect defenses. M. sexta and methyl jasmonate-induced transcriptional responses measured with a microarray enriched in herbivore-induced genes were also substantially reduced in plants grown under LN supply rates. In M. sexta-attacked LN plants, only 36 (45%) up-regulated and 46 (58%) down-regulated genes showed the same regulation as those in attacked high-N plants. However, transcriptional responses frequently directly countered the observed metabolic changes. Changes in a leaf's sensitivity to elicitation, an attacked leaf's waning ability to export oxylipin wound signals, and/or resource limitations in LN plants can account for the observed results, underscoring the conclusion that defense activation is a resource-intensive response. PMID:15133153

Differences in Nicotine Metabolism of Two Nicotiana attenuata Herbivores Render Them Differentially Susceptible to a Common Native Predator

PubMed Central

Kumar, Pavan; Rathi, Preeti; Schöttner, Matthias; Baldwin, Ian T.; Pandit, Sagar

2014-01-01

Background Nicotiana attenuata is attacked by larvae of both specialist (Manduca sexta) and generalist (Spodoptera exigua) lepidopteran herbivores in its native habitat. Nicotine is one of N. attenuata's important defenses. M. sexta is highly nicotine tolerant; whether cytochrome P450 (CYP)-mediated oxidative detoxification and/or rapid excretion is responsible for its exceptional tolerance remains unknown despite five decades of study. Recently, we demonstrated that M. sexta uses its nicotine-induced CYP6B46 to efflux midgut-nicotine into the hemolymph, facilitating nicotine exhalation that deters predatory wolf spiders (Camptocosa parallela). S. exigua's nicotine metabolism is uninvestigated. Methodology/Principal Findings We compared the ability of these two herbivores to metabolize, tolerate and co-opt ingested nicotine for defense against the wolf spider. In addition, we analyzed the spider's excretion to gain insights into its nicotine metabolism. Contrary to previous reports, we found that M. sexta larvae neither accumulate the common nicotine oxides (cotinine, cotinine N-oxide and nicotine N-oxide) nor excrete them faster than nicotine. In M. sexta larvae, ingestion of nicotine as well as its oxides increases the accumulation of CYP6B46 transcripts. In contrast, S. exigua accumulates nicotine oxides and exhales less (66%) nicotine than does M. sexta. Spiders prefer nicotine-fed S. exigua over M. sexta, a preference reversed by topical or headspace nicotine supplementation, but not ingested or topically-coated nicotine oxides, suggesting that externalized nicotine but not the nicotine detoxification products deter spider predation. The spiders also do not accumulate nicotine oxides. Conclusions Nicotine oxidation reduces S. exigua's headspace-nicotine and renders it more susceptible to predation by spiders than M. sexta, which exhales unmetabolized nicotine. These results are consistent with the hypothesis that generalist herbivores incur costs of detoxification, which include the ecological costs of greater predation risks, in addition to the previously demonstrated energetic, physiological and metabolic costs. PMID:24755743

Isolation and identification of a cardioactive peptide from Tenebrio molitor and Spodoptera eridania.

PubMed

Furuya, K; Liao, S; Reynolds, S E; Ota, R B; Hackett, M; Schooley, D A

1993-12-01

We isolated several cardioactive peptides from extracts of whole heads of the mealworm, Tenebrio molitor, and the southern armyworm, Spodoptera eridania, using a semi-isolated heart of Manduca sexta for bioassay. We have now isolated from each species the peptide with the strongest effect on rate of contraction of the heart. The peptides were identified using micro Edman sequencing and mass spectrometric methods. This cardioactive peptide has the same primary structure from both species: Pro-Phe-Cys-Asn-Ala-Phe-Thr-Gly-Cys-NH2, a cyclic nonapeptide which is identical to crustacean cardioactive peptide (CCAP) originally isolated from the shore crab, Carcinus maenas, and subsequently isolated from Locusta migratoria and Manduca sexta. This is additional evidence that CCAP has widespread occurrence in arthropoda.

A candidate pheromone receptor and two odorant receptors of the hawkmoth Manduca sexta.

PubMed

Patch, Harland M; Velarde, Rodrigo A; Walden, Kimberly K O; Robertson, Hugh M

2009-05-01

In this study, we cloned and characterized three Manduca sexta odorant receptors (ORs). One receptor is a putative pheromone receptor expressed exclusively in a cell associated with male-specific type-I trichoid sensilla. We describe the results of real-time PCR (RT-PCR) and quantitative real-time PCR (qRT-PCR) experiments that show MsextaOR1 is expressed only in male antennae. In situ hybridization labels a single cell associated with type-1 trichoid sensilla, which houses two neurons that have been previously determined to respond to the major components of the pheromone blend. The second receptor, MsextaOR2, was discovered using degenerate primers designed to conserved motifs of a unique group ORs that share as much as 88% identity. Comparison of RT-PCR, qRT-PCR, and in situ hybridization results with those of ORs in the Drosophila melanogaster Or83b subfamily shows a strong sequence and expression pattern similarity. The third receptor, MsextaOR3, was found by 5'-end sequencing of a normalized and subtracted cDNA library from male M. sexta antennae. RT-PCR and qRT-PCR show that this receptor is expressed only in male and female antennae. These are the first ORs, including a putative pheromone receptor, to be described from M. sexta.

Gustatory Receptor Neurons in Manduca sexta Contain a TrpA1-Dependent Signaling Pathway that Integrates Taste and Temperature

PubMed Central

2013-01-01

Temperature modulates the peripheral taste response of many animals, in part by activating transient receptor potential (Trp) cation channels. We hypothesized that temperature would also modulate peripheral taste responses in larval Manduca sexta. We recorded excitatory responses of the lateral and medial styloconic sensilla to chemical stimuli at 14, 22, and 30 °C. The excitatory responses to 5 chemical stimuli—a salt (KCl), 3 sugars (sucrose, glucose, and inositol) and an alkaloid (caffeine)—were unaffected by temperature. In contrast, the excitatory response to the aversive compound, aristolochic acid (AA), increased robustly with temperature. Next, we asked whether TrpA1 mediates the thermally dependent taste response to AA. To this end, we 1) identified a TrpA1 gene in M. sexta; 2) demonstrated expression of TrpA1 in the lateral and medial styloconic sensilla; 3) determined that 2 TrpA1 antagonists (HC-030031 and mecamylamine) inhibit the taste response to AA, but not caffeine; and then 4) established that the thermal dependence of the taste response to AA is blocked by HC-030031. Taken together, our results indicate that TrpA1 serves as a molecular integrator of taste and temperature in M. sexta. PMID:23828906

Flight motor modulation with speed in the hawkmoth Manduca sexta.

PubMed

Hedrick, Tyson L; Martínez-Blat, Jorge; Goodman, Mariah J

2017-01-01

The theoretical underpinnings for flight, including animal flight with flapping wings, predict a curvilinear U-shaped or J-shaped relationship between flight speed and the power required to maintain that speed. Experimental data have confirmed this relationship for a variety of bird and bat species but not insects, possibly due to differences in aerodynamics and physiology or experimental difficulties. Here we quantify modulation of the main flight motor muscles (the dorsolongitudinal and dorsoventral) via electromyography in hawkmoths (Manduca sexta) flying freely over a range of speeds in a wind tunnel and show that these insects exhibit a U-shaped speed-power relationship, with a minimum power speed of 2ms -1 , indicating that at least large flying insects achieve sufficiently high flight speeds that drag and power become limiting factors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Extensive Conserved Synteny of Genes between the Karyotypes of Manduca sexta and Bombyx mori Revealed by BAC-FISH Mapping

PubMed Central

Tanaka-Okuyama, Makiko; Shibata, Fukashi; Yoshido, Atsuo; Marec, František; Wu, Chengcang; Zhang, Hongbin; Goldsmith, Marian R.

2009-01-01

Background Genome sequencing projects have been completed for several species representing four highly diverged holometabolous insect orders, Diptera, Hymenoptera, Coleoptera, and Lepidoptera. The striking evolutionary diversity of insects argues a need for efficient methods to apply genome information from such models to genetically uncharacterized species. Constructing conserved synteny maps plays a crucial role in this task. Here, we demonstrate the use of fluorescence in situ hybridization with bacterial artificial chromosome probes as a powerful tool for physical mapping of genes and comparative genome analysis in Lepidoptera, which have numerous and morphologically uniform holokinetic chromosomes. Methodology/Principal Findings We isolated 214 clones containing 159 orthologs of well conserved single-copy genes of a sequenced lepidopteran model, the silkworm, Bombyx mori, from a BAC library of a sphingid with an unexplored genome, the tobacco hornworm, Manduca sexta. We then constructed a BAC-FISH karyotype identifying all 28 chromosomes of M. sexta by mapping 124 loci using the corresponding BAC clones. BAC probes from three M. sexta chromosomes also generated clear signals on the corresponding chromosomes of the convolvulus hawk moth, Agrius convolvuli, which belongs to the same subfamily, Sphinginae, as M. sexta. Conclusions/Significance Comparison of the M. sexta BAC physical map with the linkage map and genome sequence of B. mori pointed to extensive conserved synteny including conserved gene order in most chromosomes. Only a few rearrangements, including three inversions, three translocations, and two fission/fusion events were estimated to have occurred after the divergence of Bombycidae and Sphingidae. These results add to accumulating evidence for the stability of lepidopteran genomes. Generating signals on A. convolvuli chromosomes using heterologous M. sexta probes demonstrated that BAC-FISH with orthologous sequences can be used for karyotyping a wide range of related and genetically uncharacterized species, significantly extending the ability to develop synteny maps for comparative and functional genomics. PMID:19829706

Neuroglian-positive plasmatocytes of Manduca sexta and the initiation of hemocyte attachment to foreign surfaces.

PubMed

Nardi, James B; Pilas, Barbara; Bee, Charles Mark; Zhuang, Shufei; Garsha, Karl; Kanost, Michael R

2006-01-01

Observations of hemocyte aggregation on abiotic surfaces suggested that certain plasmatocytes from larvae of Manduca sexta act as foci for hemocyte aggregation. To establish how these particular plasmatocytes form initial attachments to foreign surfaces, they were cultured separately from other selected populations of hemocytes. While all circulating plasmatocytes immunolabel with anti-beta-integrin monoclonal antibody (MAb), only these larger plasmatocytes immunolabel with a MAb to the adhesion protein neuroglian. Neuroglian-negative plasmatocytes and granular cells that have been magnetically segregated from the majority of granular cells adhere to each other but fail to adhere to foreign substrata; by contrast, neuroglian-positive plasmatocytes that segregate with most granular cells adhere firmly to a substratum. Hemocytes form stable aggregates around the large, neuroglian-positive plasmatocytes. However, if neuroglian-positive plasmatocytes are separated from most granular cells, attachment of these plasmatocytes to foreign surfaces is suppressed.

Neuroglian on hemocyte surfaces is involved in homophilic and heterophilic interactions of the innate immune system of Manduca sexta.

PubMed

Zhuang, Shufei; Kelo, Lisha; Nardi, James B; Kanost, Michael R

2007-01-01

Neuroglian, a member of the L1 family of cell adhesion molecules (L1-CAMs), is expressed on surfaces of granular cells and a subset of large plasmatocytes of Manduca sexta that act as foci for hemocyte aggregation during the innate immune response. Neuroglian expressed on surfaces of transfected Sf9 cells induced their homophilic aggregation, with the aggregation being abolished in the presence of recombinant immunoglobulin (Ig) domains of neuroglian. Neuroglian and its Ig domains also can interact with hemocyte-specific integrin (HS integrin) as demonstrated with an enzyme-linked immunoassay and a surface plasmon resonance (SPR) assay. Neuroglian double-stranded (ds) RNA not only depresses expression of neuroglian in hemocytes but also depresses the cell-mediated encapsulation response of these hemocytes to foreign surfaces. After injection of a monoclonal antibody (MAb 3B11) into M. sexta larvae that recognizes the Ig domains of neuroglian, the cell-mediated encapsulation response of hemocytes was likewise inhibited. The Ig domains of neuroglian are involved in both homophilic and heterophilic interactions, and subsets of these six different Ig domains may affect different functions of neuroglian.

Integrated modeling of protein-coding genes in the Manduca sexta genome using RNA-Seq data from the biochemical model insect

PubMed Central

Cao, Xiaolong; Jiang, Haobo

2015-01-01

The genome sequence of Manduca sexta was recently determined using 454 technology. Cufflinks and MAKER2 were used to establish gene models in the genome assembly based on the RNA-Seq data and other species' sequences. Aided by the extensive RNA-Seq data from 50 tissue samples at various life stages, annotators over the world (including the present authors) have manually confirmed and improved a small percentage of the models after spending months of effort. While such collaborative efforts are highly commendable, many of the predicted genes still have problems which may hamper future research on this insect species. As a biochemical model representing lepidopteran pests, M. sexta has been used extensively to study insect physiological processes for over five decades. In this work, we assembled Manduca datasets Cufflinks 3.0, Trinity 4.0, and Oases 4.0 to assist the manual annotation efforts and development of Official Gene Set (OGS) 2.0. To further improve annotation quality, we developed methods to evaluate gene models in the MAKER2, Cufflinks, Oases and Trinity assemblies and selected the best ones to constitute MCOT 1.0 after thorough crosschecking. MCOT 1.0 has 18,089 genes encoding 31,666 proteins: 32.8% match OGS 2.0 models perfectly or near perfectly, 11,747 differ considerably, and 29.5% are absent in OGS 2.0. Future automation of this process is anticipated to greatly reduce human efforts in generating comprehensive, reliable models of structural genes in other genome projects where extensive RNA-Seq data are available. PMID:25612938

Why do Manduca sexta feed from white flowers? Innate and learnt colour preferences in a hawkmoth

NASA Astrophysics Data System (ADS)

Goyret, Joaquín; Pfaff, Michael; Raguso, Robert A.; Kelber, Almut

2008-06-01

Flower colour is an important signal used by flowering plants to attract pollinators. Many anthophilous insects have an innate colour preference that is displayed during their first foraging bouts and which could help them locate their first nectar reward. Nevertheless, learning capabilities allow insects to switch their colour preferences with experience and thus, to track variation in floral nectar availability. Manduca sexta, a crepuscular hawkmoth widely studied as a model system for sensory physiology and behaviour, visits mostly white, night-blooming flowers lacking UV reflectance throughout its range in the Americas. Nevertheless, the spectral sensitivity of the feeding behaviour of naïve moths shows a narrow peak around 450 nm wavelengths, suggesting an innate preference for the colour blue. Under more natural conditions (i.e. broader wavelength reflectance) than in previous studies, we used dual choice experiments with blue- and white-coloured feeders to investigate the innate preference of naïve moths and trained different groups to each colour to evaluate their learning capabilities. We confirmed the innate preference of M. sexta for blue and found that these moths were able to switch colour preferences after training experience. These results unequivocally demonstrate that M. sexta moths innately prefer blue when presented against white flower models and offer novel experimental evidence supporting the hypothesis that learning capabilities could be involved in their foraging preferences, including their widely observed attraction to white flowers in nature.

Why do Manduca sexta feed from white flowers? Innate and learnt colour preferences in a hawkmoth.

PubMed

Goyret, Joaquín; Pfaff, Michael; Raguso, Robert A; Kelber, Almut

2008-06-01

Flower colour is an important signal used by flowering plants to attract pollinators. Many anthophilous insects have an innate colour preference that is displayed during their first foraging bouts and which could help them locate their first nectar reward. Nevertheless, learning capabilities allow insects to switch their colour preferences with experience and thus, to track variation in floral nectar availability. Manduca sexta, a crepuscular hawkmoth widely studied as a model system for sensory physiology and behaviour, visits mostly white, night-blooming flowers lacking UV reflectance throughout its range in the Americas. Nevertheless, the spectral sensitivity of the feeding behaviour of naïve moths shows a narrow peak around 450 nm wavelengths, suggesting an innate preference for the colour blue. Under more natural conditions (i.e. broader wavelength reflectance) than in previous studies, we used dual choice experiments with blue- and white-coloured feeders to investigate the innate preference of naïve moths and trained different groups to each colour to evaluate their learning capabilities. We confirmed the innate preference of M. sexta for blue and found that these moths were able to switch colour preferences after training experience. These results unequivocally demonstrate that M. sexta moths innately prefer blue when presented against white flower models and offer novel experimental evidence supporting the hypothesis that learning capabilities could be involved in their foraging preferences, including their widely observed attraction to white flowers in nature.

Floral Trait Associations in Hawkmoth-Specialized and Mixed Pollination Systems

USDA-ARS?s Scientific Manuscript database

Variation in floral traits including odor, color and morphology, demonstrate the selective pressures imposed by specific pollinator taxa, such as insects and birds. In southern Arizona, Manduca sexta (Sphingidae) hawkmoths are associated with Datura wrightii (Solanaceae) at both the larval (herbivo...

Isolation and maintenance-free culture of contractile myotubes from Manduca sexta embryos.

PubMed

Baryshyan, Amanda L; Woods, William; Trimmer, Barry A; Kaplan, David L

2012-01-01

Skeletal muscle tissue engineering has the potential to treat tissue loss and degenerative diseases. However, these systems are also applicable for a variety of devices where actuation is needed, such as microelectromechanical systems (MEMS) and robotics. Most current efforts to generate muscle bioactuators are focused on using mammalian cells, which require exacting conditions for survival and function. In contrast, invertebrate cells are more environmentally robust, metabolically adaptable and relatively autonomous. Our hypothesis is that the use of invertebrate muscle cells will obviate many of the limitations encountered when mammalian cells are used for bioactuation. We focus on the tobacco hornworm, Manduca sexta, due to its easy availability, large size and well-characterized muscle contractile properties. Using isolated embryonic cells, we have developed culture conditions to grow and characterize contractile M. sexta muscles. The insect hormone 20-hydroxyecdysone was used to induce differentiation in the system, resulting in cells that stained positive for myosin, contract spontaneously for the duration of the culture, and do not require media changes over periods of more than a month. These cells proliferate under normal conditions, but the application of juvenile hormone induced further proliferation and inhibited differentiation. Cellular metabolism under normal and low glucose conditions was compared for C2C12 mouse and M. sexta myoblast cells. While differentiated C2C12 cells consumed glucose and produced lactate over one week as expected, M. sexta muscle did not consume significant glucose, and lactate production exceeded mammalian muscle production on a per cell basis. Contractile properties were evaluated using index of movement analysis, which demonstrated the potential of these cells to perform mechanical work. The ability of cultured M. sexta muscle to continuously function at ambient conditions without medium replenishment, combined with the interesting metabolic properties, suggests that this cell source is a promising candidate for further investigation toward bioactuator applications.

The COP9 signalosome controls jasmonic acid synthesis and plant responses to herbivory and pathogens.

PubMed

Hind, Sarah R; Pulliam, Sarah E; Veronese, Paola; Shantharaj, Deepak; Nazir, Azka; Jacobs, Nekaiya S; Stratmann, Johannes W

2011-02-01

The COP9 signalosome (CSN) is a multi-protein complex that regulates the activities of cullin-RING E3 ubiquitin ligases (CRLs). CRLs ubiquitinate proteins in order to target them for proteasomal degradation. The CSN is required for proper plant development. Here we show that the CSN also has a profound effect on plant defense responses. Silencing of genes for CSN subunits in tomato plants resulted in a mild morphological phenotype and reduced expression of wound-responsive genes in response to mechanical wounding, attack by Manduca sexta larvae, and Prosystemin over-expression. In contrast, expression of pathogenesis-related genes was increased in a stimulus-independent manner in these plants. The reduced wound response in CSN-silenced plants corresponded with reduced synthesis of jasmonic acid (JA), but levels of salicylic acid (SA) were unaltered. As a consequence, these plants exhibited reduced resistance against herbivorous M. sexta larvae and the necrotrophic fungal pathogen Botrytis cinerea. In contrast, susceptibility to tobacco mosaic virus (TMV) was not altered in CSN-silenced plants. These data demonstrate that the CSN orchestrates not only plant development but also JA-dependent plant defense responses. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

Discovery of a Manduca sexta Allatotropin Antagonist from a Manduca sexta Allatotropin Receptor Homology Model.

PubMed

Kai, Zhen-Peng; Zhu, Jing-Jing; Deng, Xi-Le; Yang, Xin-Ling; Chen, Shan-Shan

2018-04-03

Insect G protein coupled receptors (GPCRs) have important roles in modulating biology, physiology and behavior. They have been identified as candidate targets for next-generation insecticides, yet these targets have been relatively poorly exploited for insect control. In this study, we present a pipeline of novel Manduca sexta allatotropin (Manse-AT) antagonist discovery with homology modeling, docking, molecular dynamics simulation and structure-activity relationship. A series of truncated and alanine-replacement analogs of Manse-AT were assayed for the stimulation of juvenile hormone biosynthesis. The minimum sequence required to retain potent biological activity is the C -terminal amidated octapeptide Manse-AT (6-13). We identified three residues essential for bioactivity (Thr⁴, Arg6 and Phe⁸) by assaying alanine-replacement analogs of Manse-AT (6-13). Alanine replacement of other residues resulted in reduced potency but bioactivity was retained. The 3D structure of the receptor (Manse-ATR) was built and the binding pocket was identified. The binding affinities of all the analogs were estimated by calculating the free energy of binding. The calculated binding affinities corresponded to the biological activities of the analogs, which supporting our localization of the binding pocket. Then, based on the docking and molecular dynamics studies of Manse-AT (10-13), we described it can act as a potent Manse-AT antagonist. The antagonistic effect on JH biosynthesis of Manse-AT (10-13) validated our hypothesis. The IC 50 value of antagonist Manse-AT (10-13) is 0.9 nM. The structure-activity relationship of antagonist Manse-AT (10-13) was also studied for the further purpose of investigating theoretically the structure factors influencing activity. These data will be useful for the design of new Manse-AT agonist and antagonist as potential pest control agents.

Integrated modeling of protein-coding genes in the Manduca sexta genome using RNA-Seq data from the biochemical model insect.

PubMed

Cao, Xiaolong; Jiang, Haobo

2015-07-01

The genome sequence of Manduca sexta was recently determined using 454 technology. Cufflinks and MAKER2 were used to establish gene models in the genome assembly based on the RNA-Seq data and other species' sequences. Aided by the extensive RNA-Seq data from 50 tissue samples at various life stages, annotators over the world (including the present authors) have manually confirmed and improved a small percentage of the models after spending months of effort. While such collaborative efforts are highly commendable, many of the predicted genes still have problems which may hamper future research on this insect species. As a biochemical model representing lepidopteran pests, M. sexta has been used extensively to study insect physiological processes for over five decades. In this work, we assembled Manduca datasets Cufflinks 3.0, Trinity 4.0, and Oases 4.0 to assist the manual annotation efforts and development of Official Gene Set (OGS) 2.0. To further improve annotation quality, we developed methods to evaluate gene models in the MAKER2, Cufflinks, Oases and Trinity assemblies and selected the best ones to constitute MCOT 1.0 after thorough crosschecking. MCOT 1.0 has 18,089 genes encoding 31,666 proteins: 32.8% match OGS 2.0 models perfectly or near perfectly, 11,747 differ considerably, and 29.5% are absent in OGS 2.0. Future automation of this process is anticipated to greatly reduce human efforts in generating comprehensive, reliable models of structural genes in other genome projects where extensive RNA-Seq data are available. Copyright © 2015 Elsevier Ltd. All rights reserved.

The immune signaling pathways of Manduca sexta

PubMed Central

Cao, Xiaolong; He, Yan; Hu, Yingxia; Wang, Yang; Chen, Yun-Ru; Bryant, Bart; Clem, Rollie J.; Schwartz, Lawrence M.; Blissard, Gary; Jiang, Haobo

2015-01-01

Signal transduction pathways and their coordination are critically important for proper functioning of animal immune systems. Our knowledge of the constituents of the intracellular signaling network in insects mainly comes from genetic analyses in Drosophila melanogaster. To facilitate future studies of similar systems in the tobacco hornworm and other lepidopteran insects, we have identified and examined the homologous genes in the genome of Manduca sexta. Based on 1:1 orthologous relationships in most cases, we hypothesize that the Toll, Imd, MAPK-JNK-p38 and JAK-STAT pathways are intact and operative in this species, as are most of the regulatory mechanisms. Similarly, cellular processes such as autophagy, apoptosis and RNA interference probably function in similar ways, because their mediators and modulators are mostly conserved in this lepidopteran species. We have annotated a total of 186 genes encoding 199 proteins, studied their domain structures and evolution, and examined their mRNA levels in tissues at different life stages. Such information provides a genomic perspective of the intricate signaling system in a non-drosophiline insect. PMID:25858029

Humidity Detection and Hygropreference Behavior in Larvae of the Tobacco hornworm, Manduca sexta

PubMed Central

Rowley, Marc; Hanson, Frank

2007-01-01

Water is a critical resource for any terrestrial animal, especially for a soft-bodied insect such as larvae of the tobacco hornworm, Manduca sexta L. (Lepidoptera: Sphingidae). Strategies for coping with a dry environment might include seeking out regions of high relative humidity that reduce desiccative stress, or to find and imbibe liquid water. Desiccated larvae placed in a linear arena with a humidity gradient preferred the humid end, whereas un-desiccated larvae did not. This behavior was not affected by temperature. Ablation or occlusion of the antennae showed that they are required to mediate this behavior. A series of experiments showed that control larvae oriented towards and imbibed liquid water whereas those whose antennae had been occluded with wax did not. Electrophysiological recordings from the lateral basiconic sensillum of the second antennal segment revealed the presence of at least one hygroreceptive unit that greatly increased its firing rate in response to moist air, decreased firing rates in response to dry air, and showed mild post-stimulatory inhibition. PMID:20302460

Multifaceted biological insights from a draft genome sequence of the tobacco hornworm moth, Manduca sexta

PubMed Central

Kanost, Michael R.; Arrese, Estela L.; Cao, Xiaolong; Chen, Yun-Ru; Chellapilla, Sanjay; Goldsmith, Marian R; Grosse-Wilde, Ewald; Heckel, David G.; Herndon, Nicolae; Jiang, Haobo; Papanicolaou, Alexie; Qu, Jiaxin; Soulages, Jose L.; Vogel, Heiko; Walters, James; Waterhouse, Robert M.; Ahn, Seung-Joon; Almeida, Francisca C.; An, Chunju; Aqrawi, Peshtewani; Bretschneider, Anne; Bryant, William B.; Bucks, Sascha; Chao, Hsu; Chevignon, Germain; Christen, Jayne M.; Clarke, David F.; Dittmer, Neal T.; Ferguson, Laura C.F.; Garavelou, Spyridoula; Gordon, Karl H.J.; Gunaratna, Ramesh T.; Han, Yi; Hauser, Frank; He, Yan; Heidel-Fischer, Hanna; Hirsh, Ariana; Hu, Yingxia; Jiang, Hongbo; Kalra, Divya; Klinner, Christian; König, Christopher; Kovar, Christie; Kroll, Ashley R.; Kuwar, Suyog S.; Lee, Sandy L.; Lehman, Rüdiger; Li, Kai; Li, Zhaofei; Liang, Hanquan; Lovelace, Shanna; Lu, Zhiqiang; Mansfield, Jennifer H.; McCulloch, Kyle J.; Mathew, Tittu; Morton, Brian; Muzny, Donna M.; Neunemann, David; Ongeri, Fiona; Pauchet, Yannick; Pu, Ling-Ling; Pyrousis, Ioannis; Rao, Xiang-Jun; Redding, Amanda; Roesel, Charles; Sanchez-Gracia, Alejandro; Schaack, Sarah; Shukla, Aditi; Tetreau, Guillaume; Wang, Yang; Xiong, Guang-Hua; Traut, Walther; Walsh, Tom K.; Worley, Kim C.; Wu, Di; Wu, Wenbi; Wu, Yuan-Qing; Zhang, Xiufeng; Zou, Zhen; Zucker, Hannah; Briscoe, Adriana D.; Burmester, Thorsten; Clem, Rollie J.; Feyereisen, René; Grimmelikhuijzen, Cornelis J.P; Hamodrakas, Stavros J.; Hansson, Bill S.; Huguet, Elisabeth; Jermiin, Lars S.; Lan, Que; Lehman, Herman K.; Lorenzen, Marce; Merzendorfer, Hans; Michalopoulos, Ioannis; Morton, David B.; Muthukrishnan, Subbaratnam; Oakeshott, John G.; Palmer, Will; Park, Yoonseong; Passarelli, A. Lorena; Rozas, Julio; Schwartz, Lawrence M.; Smith, Wendy; Southgate, Agnes; Vilcinskas, Andreas; Vogt, Richard; Wang, Ping; Werren, John; Yu, Xiao-Qiang; Zhou, Jing-Jiang; Brown, Susan J.; Scherer, Steven E.; Richards, Stephen; Blissard, Gary W.

2016-01-01

Manduca sexta, known as the tobacco hornworm or Carolina sphinx moth, is a lepidopteran insect that is used extensively as a model system for research in insect biochemistry, physiology, neurobiology, development, and immunity. One important benefit of this species as an experimental model is its extremely large size, reaching more than 10 g in the larval stage. M. sexta larvae feed on solanaceous plants and thus must tolerate a substantial challenge from plant allelochemicals, including nicotine. We report the sequence and annotation of the M. sexta genome, and a survey of gene expression in various tissues and developmental stages. The Msex_1.0 genome assembly resulted in a total genome size of 419.4 Mbp. Repetitive sequences accounted for 25.8% of the assembled genome. The official gene set is comprised of 15,451 protein-coding genes, of which 2498 were manually curated. Extensive RNA-seq data from many tissues and developmental stages were used to improve gene models and for insights into gene expression patterns. Genome wide synteny analysis indicated a high level of macrosynteny in the Lepidoptera. Annotation and analyses were carried out for gene families involved in a wide spectrum of biological processes, including apoptosis, vacuole sorting, growth and development, structures of exoskeleton, egg shells, and muscle, vision, chemosensation, ion channels, signal transduction, neuropeptide signaling, neurotransmitter synthesis and transport, nicotine tolerance, lipid metabolism, and immunity. This genome sequence, annotation, and analysis provide an important new resource from a well-studied model insect species and will facilitate further biochemical and mechanistic experimental studies of many biological systems in insects. PMID:27522922

Complete Dosage Compensation and Sex-Biased Gene Expression in the Moth Manduca sexta

PubMed Central

Smith, Gilbert; Chen, Yun-Ru; Blissard, Gary W.; Briscoe, Adriana D.

2014-01-01

Sex chromosome dosage compensation balances homogametic sex chromosome expression with autosomal expression in the heterogametic sex, leading to sex chromosome expression parity between the sexes. If compensation is incomplete, this can lead to expression imbalance and sex-biased gene expression. Recent work has uncovered an intriguing and variable pattern of dosage compensation across species that includes a lack of complete dosage compensation in ZW species compared with XY species. This has led to the hypothesis that ZW species do not require complete compensation or that complete compensation would negatively affect their fitness. To date, only one study, a study of the moth Bombyx mori, has discovered evidence for complete dosage compensation in a ZW species. We examined another moth species, Manduca sexta, using high-throughput sequencing to survey gene expression in the head tissue of males and females. We found dosage compensation to be complete in M. sexta with average expression between the Z chromosome in males and females being equal. When genes expressed at very low levels are removed by filtering, we found that average autosome expression was highly similar to average Z expression, suggesting that the majority of genes in M. sexta are completely dosage compensated. Further, this compensation was accompanied by sex-specific gene expression associated with important sexually dimorphic traits. We suggest that complete dosage compensation in ZW species might be more common than previously appreciated and linked to additional selective processes, such as sexual selection. More ZW and lepidopteran species should now be examined in a phylogenetic framework, to understand the evolution of dosage compensation. PMID:24558255

Manduca sexta proprophenoloxidase activating proteinase-3 (PAP3) stimulates melanization by activating proPAP3, proSPHs, and proPOs

PubMed Central

Wang, Yang; Lu, Zhiqiang; Jiang, Haobo

2014-01-01

Melanization participates in various insect physiological processes including antimicrobial immune responses. Phenoloxidase (PO), a critical component of the enzyme system catalyzing melanin formation, is produced as an inactive precursor prophenoloxidase (proPO) and becomes active via specific proteolytic cleavage by proPO activating proteinase (PAP). In Manduca sexta, three PAPs can activate proPOs in the presence of two serine proteinase homologs (SPH1 and SPH2). While the hemolymph proteinases (HPs) that generate the active PAPs are known, it is unclear how the proSPHs (especially proSPH1) are activated. In this study, we isolated from plasma of bar-stage M. sexta larvae an Ile-Glu-Ala-Arg-p-nitroanilide hydrolyzing enzyme that cleaved the proSPHs. This proteinase, PAP3, generated active SPH1 and SPH2, which function as cofactors for PAP3 in proPO activation. Cleavage of the purified recombinant proSPHs by PAP3 yielded 38 kDa bands similar in mobility to the SPHs formed in vivo. Surprisingly, PAP3 also can activate proPAP3 to stimulate melanization in a direct positive feedback loop. The enhanced proPO activation concurred with the cleavage activation of proHP6, proHP8, proPAP1, proPAP3, proSPH1, proSPH2, proPOs, but not proHP14 or proHP21. These results indicate that PAP3, like PAP1, is a key factor of the self-reinforcing mechanism in the proPO activation system, which is linked to other immune responses in M. sexta. PMID:24768974

Characterization of toxin complex gene clusters and insect toxicity of bacteria representing four subgroups of Pseudomonas fluorescens

USDA-ARS?s Scientific Manuscript database

Ten strains representing four lineages of Pseudomonas (P. chlororaphis, P. corrugata, P. koreensis, and P. fluorescens subgroups) were evaluated for toxicity to the tobacco hornworm Manduca sexta and the fruit fly Drosophila melanogaster. The three strains within the P. chlororaphis subgroup exhibi...

3D-Reconstructions and Virtual 4D-Visualization to Study Metamorphic Brain Development in the Sphinx Moth Manduca Sexta

PubMed Central

Huetteroth, Wolf; el Jundi, Basil; el Jundi, Sirri; Schachtner, Joachim

2009-01-01

During metamorphosis, the transition from the larva to the adult, the insect brain undergoes considerable remodeling: new neurons are integrated while larval neurons are remodeled or eliminated. One well acknowledged model to study metamorphic brain development is the sphinx moth Manduca sexta. To further understand mechanisms involved in the metamorphic transition of the brain we generated a 3D standard brain based on selected brain areas of adult females and 3D reconstructed the same areas during defined stages of pupal development. Selected brain areas include for example mushroom bodies, central complex, antennal- and optic lobes. With this approach we eventually want to quantify developmental changes in neuropilar architecture, but also quantify changes in the neuronal complement and monitor the development of selected neuronal populations. Furthermore, we used a modeling software (Cinema 4D) to create a virtual 4D brain, morphing through its developmental stages. Thus the didactical advantages of 3D visualization are expanded to better comprehend complex processes of neuropil formation and remodeling during development. To obtain datasets of the M. sexta brain areas, we stained whole brains with an antiserum against the synaptic vesicle protein synapsin. Such labeled brains were then scanned with a confocal laser scanning microscope and selected neuropils were reconstructed with the 3D software AMIRA 4.1. PMID:20339481

3D-Reconstructions and Virtual 4D-Visualization to Study Metamorphic Brain Development in the Sphinx Moth Manduca Sexta.

PubMed

Huetteroth, Wolf; El Jundi, Basil; El Jundi, Sirri; Schachtner, Joachim

2010-01-01

DURING METAMORPHOSIS, THE TRANSITION FROM THE LARVA TO THE ADULT, THE INSECT BRAIN UNDERGOES CONSIDERABLE REMODELING: new neurons are integrated while larval neurons are remodeled or eliminated. One well acknowledged model to study metamorphic brain development is the sphinx moth Manduca sexta. To further understand mechanisms involved in the metamorphic transition of the brain we generated a 3D standard brain based on selected brain areas of adult females and 3D reconstructed the same areas during defined stages of pupal development. Selected brain areas include for example mushroom bodies, central complex, antennal- and optic lobes. With this approach we eventually want to quantify developmental changes in neuropilar architecture, but also quantify changes in the neuronal complement and monitor the development of selected neuronal populations. Furthermore, we used a modeling software (Cinema 4D) to create a virtual 4D brain, morphing through its developmental stages. Thus the didactical advantages of 3D visualization are expanded to better comprehend complex processes of neuropil formation and remodeling during development. To obtain datasets of the M. sexta brain areas, we stained whole brains with an antiserum against the synaptic vesicle protein synapsin. Such labeled brains were then scanned with a confocal laser scanning microscope and selected neuropils were reconstructed with the 3D software AMIRA 4.1.

Recognition of microbial molecular patterns and stimulation of prophenoloxidase activation by a β-1,3-glucanase-related protein in Manduca sexta larval plasma

PubMed Central

Wang, Yang; Sumathipala, Niranji; Rayaprolu, Subrahmanyam; Jiang, Haobo

2011-01-01

Detection of pathogenic invaders is the essential first step of a successful defense response in multicellular organisms. In this study, we have identified a new member of the β-1,3-glucanase-related protein superfamily from the tobacco hornworm Manduca sexta. This protein, designated microbe binding protein (MBP), is 61% identical in sequence to Bombyx mori Gram-negative bacteria binding protein, but only 34-36% identical to M. sexta β-1,3-glucan recognition protein-1 and 2. Its mRNA levels were strongly up-regulated in hemocytes and fat body of immune challenged larvae, along with an increase in concentration of the plasma protein. We expressed M. sexta MBP in a baculovirus-insect cell system. The purified protein associated with intact bacteria and fungi. It specifically bound to lipoteichoic acid, lipopolysaccharide, diaminopimelic acid-type peptidoglycans (DAP-PGs) from Escherichia coli and Bacillus subtilis, but less so to laminarin or Lys-type PG from Staphylococcus aureus. The complex binding pattern was influenced by other plasma factors and additional microbial surface molecules. After different amounts of MBP had been incubated with larval plasma on ice, a concentration-dependent increase in phenoloxidase (PO) activity occurred in the absence of any microbial elicitor. The activity increase was also observed in the mixture of plasma and a bacterial or fungal cell wall component. The prophenoloxidase (proPO) activation became more prominent when DAP-PGs, Micrococcus luteus Lys-PG, or lipoteichoic acid was included in the mixture of MBP and plasma. Statistic analysis suggested that a synergistic enhancement of proPO activation was caused by an interaction between MBP and these elicitors, but not S. aureus Lys-PG, lipopolysaccharide, curdlan, or laminarin. These data indicate that M. sexta MBP is a component of the surveillance mechanism and, by working together with other pattern recognition molecules and serine proteinases, triggers the proPO activation system. PMID:21296155

Multifaceted biological insights from a draft genome sequence of the tobacco hornworm moth, Manduca sexta.

PubMed

Kanost, Michael R; Arrese, Estela L; Cao, Xiaolong; Chen, Yun-Ru; Chellapilla, Sanjay; Goldsmith, Marian R; Grosse-Wilde, Ewald; Heckel, David G; Herndon, Nicolae; Jiang, Haobo; Papanicolaou, Alexie; Qu, Jiaxin; Soulages, Jose L; Vogel, Heiko; Walters, James; Waterhouse, Robert M; Ahn, Seung-Joon; Almeida, Francisca C; An, Chunju; Aqrawi, Peshtewani; Bretschneider, Anne; Bryant, William B; Bucks, Sascha; Chao, Hsu; Chevignon, Germain; Christen, Jayne M; Clarke, David F; Dittmer, Neal T; Ferguson, Laura C F; Garavelou, Spyridoula; Gordon, Karl H J; Gunaratna, Ramesh T; Han, Yi; Hauser, Frank; He, Yan; Heidel-Fischer, Hanna; Hirsh, Ariana; Hu, Yingxia; Jiang, Hongbo; Kalra, Divya; Klinner, Christian; König, Christopher; Kovar, Christie; Kroll, Ashley R; Kuwar, Suyog S; Lee, Sandy L; Lehman, Rüdiger; Li, Kai; Li, Zhaofei; Liang, Hanquan; Lovelace, Shanna; Lu, Zhiqiang; Mansfield, Jennifer H; McCulloch, Kyle J; Mathew, Tittu; Morton, Brian; Muzny, Donna M; Neunemann, David; Ongeri, Fiona; Pauchet, Yannick; Pu, Ling-Ling; Pyrousis, Ioannis; Rao, Xiang-Jun; Redding, Amanda; Roesel, Charles; Sanchez-Gracia, Alejandro; Schaack, Sarah; Shukla, Aditi; Tetreau, Guillaume; Wang, Yang; Xiong, Guang-Hua; Traut, Walther; Walsh, Tom K; Worley, Kim C; Wu, Di; Wu, Wenbi; Wu, Yuan-Qing; Zhang, Xiufeng; Zou, Zhen; Zucker, Hannah; Briscoe, Adriana D; Burmester, Thorsten; Clem, Rollie J; Feyereisen, René; Grimmelikhuijzen, Cornelis J P; Hamodrakas, Stavros J; Hansson, Bill S; Huguet, Elisabeth; Jermiin, Lars S; Lan, Que; Lehman, Herman K; Lorenzen, Marce; Merzendorfer, Hans; Michalopoulos, Ioannis; Morton, David B; Muthukrishnan, Subbaratnam; Oakeshott, John G; Palmer, Will; Park, Yoonseong; Passarelli, A Lorena; Rozas, Julio; Schwartz, Lawrence M; Smith, Wendy; Southgate, Agnes; Vilcinskas, Andreas; Vogt, Richard; Wang, Ping; Werren, John; Yu, Xiao-Qiang; Zhou, Jing-Jiang; Brown, Susan J; Scherer, Steven E; Richards, Stephen; Blissard, Gary W

2016-09-01

Manduca sexta, known as the tobacco hornworm or Carolina sphinx moth, is a lepidopteran insect that is used extensively as a model system for research in insect biochemistry, physiology, neurobiology, development, and immunity. One important benefit of this species as an experimental model is its extremely large size, reaching more than 10 g in the larval stage. M. sexta larvae feed on solanaceous plants and thus must tolerate a substantial challenge from plant allelochemicals, including nicotine. We report the sequence and annotation of the M. sexta genome, and a survey of gene expression in various tissues and developmental stages. The Msex_1.0 genome assembly resulted in a total genome size of 419.4 Mbp. Repetitive sequences accounted for 25.8% of the assembled genome. The official gene set is comprised of 15,451 protein-coding genes, of which 2498 were manually curated. Extensive RNA-seq data from many tissues and developmental stages were used to improve gene models and for insights into gene expression patterns. Genome wide synteny analysis indicated a high level of macrosynteny in the Lepidoptera. Annotation and analyses were carried out for gene families involved in a wide spectrum of biological processes, including apoptosis, vacuole sorting, growth and development, structures of exoskeleton, egg shells, and muscle, vision, chemosensation, ion channels, signal transduction, neuropeptide signaling, neurotransmitter synthesis and transport, nicotine tolerance, lipid metabolism, and immunity. This genome sequence, annotation, and analysis provide an important new resource from a well-studied model insect species and will facilitate further biochemical and mechanistic experimental studies of many biological systems in insects. Copyright © 2016 Elsevier Ltd. All rights reserved.

The discovery of a novel antagonist - Manduca sexta allatotropin analogue - as an insect midgut active ion transport inhibitor.

PubMed

Deng, Xi-le; Kai, Zhen-Peng; Chamberlin, Mary E; Horodyski, Frank M; Yang, Xin-Ling

2016-11-01

The midgut is an important site for both nutrient absorption and ionic regulation in lepidopteran larvae, major pests in agriculture. The larval lepidopteran midgut has become a potent insecticide target over the past few decades. Recent studies have shown that an insect neuropeptide, Manduca sexta allatotropin (Manse-AT), exhibits inhibition of active ion transport (AIT) across the larval midgut epithelium. The full characteristic of the AIT inhibition capacity of Manse-AT is essential to assay. In this study, AIT inhibition across the M. sexta midgut by Manse-AT and its analogues in a range of concentrations was assayed. The structure-activity relationship of Manse-AT was also studied by truncated and alanine-replacement strategies. Our results identified three residues, Thr4, Arg6 and Phe8, as the most important components for activity on the midgut. Replacement of Glu1, Met2 and Met3 reduced the potency of the analogues. The conservative substitution of Gly7 with alanine had little effect on the potency of the analogues. We demonstrated for the first time that Manse-AT (10-13) behaves as a potent antagonist in vitro on active ion transport across the epithelium of the posterior midgut in M. sexta. Structure-activity studies of Manse-AT are useful in developing lead compounds for the design and testing of synthetic antagonists, ultimately to develop potent and specific pest control strategies. Manse-AT (10-13) has been discovered as the first Manse-AT antagonist, with a significant effect and a short sequence compared with other insect neuropeptides. It may be a new potential pest control agent in the future. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Magnetic Resonance Imaging of Alimentary Tract Development in Manduca sexta

PubMed Central

Rowland, Ian J.; Goodman, Walter G.

2016-01-01

Non-invasive 3D magnetic resonance imaging techniques were used to investigate metamorphosis of the alimentary tract of Manduca sexta from the larval to the adult stage. The larval midgut contracts in volume immediately following cessation of feeding and then greatly enlarges during the late pharate pupal period. Magnetic resonance imaging revealed that the foregut and hindgut of the pharate pupa undergo ecdysis considerably earlier than the external exoskeleton. Expansion of air sacs in the early pupa and development of flight muscles several days later appear to orient the midgut into its adult position in the abdomen. The crop, an adult auxiliary storage organ, begins development as a dorsal outgrowth of the foregut. This coincides with a reported increase in pupal ecdysteroid titers. An outgrowth of the hindgut, the rectal sac, appears several days later and continues to expand until it nearly fills the dorsal half of the abdominal cavity. This development correlates with a second rise in pupal ecdysteroid titers. In the pharate pupa, the presence of paramagnetic species renders the silk glands hyperintense. PMID:27280776

Arylphorin from Manduca sexta: carbohydrate structure and immunological studies.

PubMed

Ryan, R O; Anderson, D R; Grimes, W J; Law, J H

1985-11-15

The major hemolymph protein in the last larval stage of Manduca sexta is a hexameric glycoprotein, arylphorin (Mr = 450,000). Sodium dodecyl sulfate polyacrylamide gel electrophoresis of purified arylphorin reveals the presence of two subunits, A1 and A2. Both subunits are glycosylated and have apparent Mr = 77,000 and 72,000, respectively. Pronase digestion of arylphorin yielded a single major glycopeptide. 250 MHz NMR spectroscopy of arylphorin glycopeptide revealed a Man9GlcNAc2 oligosaccharide structure similar to that observed in mammalian glycoproteins. Endoglycosidase-H treatment of arylphorin was employed to remove covalently linked carbohydrate residues. The carbohydrate removal lowered the apparent Mr of subunits A1 and A2 to 72,000 and 69,000, respectively, indicating that the difference in arylphorin subunit size is not due to levels of glycosylation. Immunoblotting experiments with anti-arylphorin antiserum and Bombyx mori storage proteins indicated cross reactivity with the corresponding arylphorin of this insect. Preparation of subunit A2 monospecific antibodies, followed by immunoblotting of arylphorin showed a close immunological relationship between subunits A1 and A2.

Silencing of a Germin-Like Gene in Nicotiana attenuata Improves Performance of Native Herbivores1[W

PubMed Central

Lou, Yonggen; Baldwin, Ian T.

2006-01-01

Germins and germin-like proteins (GLPs) are known to function in pathogen resistance, but their involvement in defense against insect herbivores is poorly understood. In the native tobacco Nicotiana attenuata, attack from the specialist herbivore Manduca sexta or elicitation by adding larval oral secretions (OS) to wounds up-regulates transcripts of a GLP. To understand the function of this gene, which occurs as a single copy, we cloned the full-length NaGLP and silenced its expression in N. attenuata by expressing a 250-bp fragment in an antisense orientation with an Agrobacterium-based transformation system and by virus-induced gene silencing (VIGS). Homozygous lines harboring a single insert and VIGS plants had significantly reduced constitutive (measured in roots) and elicited NaGLP transcript levels (in leaves). Silencing NaGLP improved M. sexta larval performance and Tupiocoris notatus preference, two native herbivores of N. attenuata. Silencing NaGLP also attenuated the OS-induced hydrogen peroxide (H2O2), diterpene glycosides, and trypsin proteinase inhibitor responses, which may explain the observed susceptibility of antisense or VIGS plants to herbivore attack and increased nicotine contents, but did not influence the OS-elicited jasmonate and salicylate bursts, or the release of the volatile organic compounds (limonene, cis-α-bergamotene, and germacrene-A) that function as an indirect defense. This suggests that NaGLP is involved in H2O2 production and might also be related to ethylene production and/or perception, which in turn influences the defense responses of N. attenuata via H2O2 and ethylene-signaling pathways. PMID:16461381

Embryonic integument and "molts" in Manduca sexta (Insecta, Lepidoptera).

PubMed

Ziese, Stefanie; Dorn, August

2003-02-01

In Manduca sexta the germ band is formed 12 h post-oviposition (p.o.) (=10% development completed) and is located above the yolk at the egg surface. The cells show a polar organization. They are engaged in the uptake and degradation of yolk globules, pinched off from the yolk cells. This process can be observed in the integumental cells during the first growth phase of the embryo that lasts until "katatrepsis," an embryonic movement that takes place at 40% development completed. At 37% development completed, the ectoderm deposits a thin membrane at its apical surface, the first embryonic membrane, which detaches immediately before katatrepsis. The second period of embryonic growth--from katatrepsis to 84 h p.o. (70% development completed)--starts with the deposition of a second embryonic membrane that is somewhat thicker than the first one and shows a trilaminar, cuticulin-like structure. Whereas the apical cell surface is largely smooth during the deposition of the first embryonic membrane, it forms microvilli during deposition of the second one. At the same time, uptake of formed yolk material ceases and the epidermal cells now contain clusters of mitochondria below the apical surface. Rough endoplasmic reticulum (RER) increases in the perinuclear region. The second embryonic membrane detaches about 63 h p.o. At 69 h p.o., a new generation of microvilli forms and islands of a typical cuticulin layer indicate the onset of the deposition of the larval cuticle. The third growth phase is characterized by a steady increase in the embryo length, the deposition of the larval procuticle, and by cuticular tanning at about 100 h p.o. Beginning at that stage, electron-lucent vesicles aggregate below the epidermal surface and are apparently released below the larval cuticle. Manduca sexta is the first holometabolous insect in which the deposition of embryonic membranes and cuticles has been examined by electron microscopy. In correspondence with hemimetabolous insects, the embryo of M. sexta secretes three covers at approximately the same developmental stage. A marked difference: the second embryonic cover, which in Hemimetabola clearly exhibits a cuticular organization, has instead a membranous, cuticulin-like structure. We see the difference as the result of an evolutionary reductional process promoted by the redundancy of embryonic covers in the egg shell. Embryonic "molts" also occur in noninsect arthropods; their phylogenetical aspects are discussed. Copyright 2002 Wiley-Liss, Inc.

Evaluation of the Thorax of Manduca Sexta for Flapping Wing Micro Air Vehicle Applications

DTIC Science & Technology

2012-12-01

procuticle. The procuticle is comprised of microfibers of chitin enveloped by a matrix of protein. When the procuticle forms, it is similar to that of a...carbon fiber layup. There is a thin layer of lamellae with chitin microfibers oriented at different angles 15 throughout the layup. This layer can

Aerodynamic Performance and Particle Image Velocimetery of Piezo Actuated Biomimetic Manduca Sexta Engineered Wings Towards the Design and Application of a Flapping Wing Flight Vehicle

DTIC Science & Technology

2013-12-01

95 3.3. Displacement sensor ... Bio vs. engineered wing modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 3.1. High speed camera specifications...expanding and evolving mission areas, especially in the arena of bio -inspired Flap- ping Wing Micro Air Vehicles (FWMAV). This chapter will introduce the

Opsin cDNA sequences of a UV and green rhodopsin of the satyrine butterfly Bicyclus anynana.

PubMed

Vanhoutte, K J A; Eggen, B J L; Janssen, J J M; Stavenga, D G

2002-11-01

The cDNAs of an ultraviolet (UV) and long-wavelength (LW) (green) absorbing rhodopsin of the bush brown Bicyclus anynana were partially identified. The UV sequence, encoding 377 amino acids, is 76-79% identical to the UV sequences of the papilionids Papilio glaucus and Papilio xuthus and the moth Manduca sexta. A dendrogram derived from aligning the amino acid sequences reveals an equidistant position of Bicyclus between Papilio and Manduca. The sequence of the green opsin cDNA fragment, which encodes 242 amino acids, represents six of the seven transmembrane regions. At the amino acid level, this fragment is more than 80% identical to the corresponding LW opsin sequences of Dryas, Heliconius, Papilio (rhodopsin 2) and Manduca. Whereas three LW absorbing rhodopsins were identified in the papilionid butterflies, only one green opsin was found in B. anynana.

Manufacturing and Evaluation of a Biologically Inspired Engineered MAV Wing Compared to the Manduca Sexta Wing Under Simulated Flapping Conditions

DTIC Science & Technology

2011-03-24

4.13. The green circle denotes a ‘ self identification’ of a reference point. This allows a user to place the cursor over what he/she thought was a...deflection’. Figure 4.27 extrap- olates the point residual values (in %) associated with the points that are resposible for providing this thesis

Asymmetry costs: effects of wing damage on hovering flight performance in the hawkmoth Manduca sexta.

PubMed

Fernández, María José; Driver, Marion E; Hedrick, Tyson L

2017-10-15

Flight performance is fundamental to the fitness of flying organisms. Whilst airborne, flying organisms face unavoidable wing wear and wing area loss. Many studies have tried to quantify the consequences of wing area loss to flight performance with varied results, suggesting that not all types of damage are equal and different species may have different means to compensate for some forms of wing damage with little to no cost. Here, we investigated the cost of control during hovering flight with damaged wings, specifically wings with asymmetric and symmetric reductions in area, by measuring maximum load lifting capacity and the metabolic power of hovering flight in hawkmoths ( Manduca sexta ). We found that while asymmetric and symmetric reductions are both costly in terms of maximum load lifting and hovering efficiency, asymmetric reductions are approximately twice as costly in terms of wing area lost. The moths also did not modulate flapping frequency and amplitude as predicted by a hovering flight model, suggesting that the ability to do so, possibly tied to asynchronous versus synchronous flight muscles, underlies the varied responses found in different wing clipping experiments. © 2017. Published by The Company of Biologists Ltd.

Developmental distribution of CaM kinase II in the antennal lobe of the sphinx moth Manduca sexta.

PubMed

Lohr, Christian; Bergstein, Sandra; Hirnet, Daniela

2007-01-01

The antennal lobe (primary olfactory center of insects) is completely reorganized during metamorphosis. This reorganization is accompanied by changing patterns of calcium signaling in neurons and glial cells. In the present study, we investigated the developmental distribution of a major calcium-dependent protein, viz., calcium/calmodulin-dependent protein kinase II (CaM kinase II), in the antennal lobe of the sphinx moth Manduca sexta by using a monoclonal antibody. During synaptogenesis (developmental stages 6-10), we found a redistribution of CaM kinase II immunoreactivity, from a homogeneous distribution in the immature neuropil to an accumulation in the neuropil of the glomeruli. CaM kinase II immunoreactivity was less intense in olfactory receptor axons of the antennal nerve and antennal lobe glial cells. Western blot analysis revealed a growing content of CaM kinase II in antennal lobe tissue throughout metamorphosis. Injection of the CaM kinase inhibitor KN-93 into pupae resulted in a reduced number of antennal lobe glial cells migrating into the neuropil to form borders around glomeruli. The results suggest that CaM kinase II is involved in glial cell migration.

Circadian clocks of both plants and pollinators influence flower seeking behavior of the pollinator hawkmoth Manduca sexta.

PubMed

Fenske, Myles P; Nguyen, LeAnn P; Horn, Erin K; Riffell, Jeffrey A; Imaizumi, Takato

2018-02-12

Most plant-pollinator interactions occur during specific periods during the day. To facilitate these interactions, many flowers are known to display their attractive qualities, such as scent emission and petal opening, in a daily rhythmic fashion. However, less is known about how the internal timing mechanisms (the circadian clocks) of plants and animals influence their daily interactions. We examine the role of the circadian clock in modulating the interaction between Petunia and one of its pollinators, the hawkmoth Manduca sexta. We find that desynchronization of the Petunia circadian clock affects moth visitation preference for Petunia flowers. Similarly, moths with circadian time aligned to plants show stronger flower-foraging activities than moths that lack this alignment. Moth locomotor activity is circadian clock-regulated, although it is also strongly repressed by light. Moths show a time-dependent burst increase in flight activity during subjective night. In addition, moth antennal responsiveness to the floral scent compounds exhibits a 24-hour rhythm in both continuous light and dark conditions. This study highlights the importance of the circadian clocks in both plants and animals as a crucial factor in initiating specialized plant-pollinator relationships.

How to perform measurements in a hovering animal's wake: physical modelling of the vortex wake of the hawkmoth, Manduca sexta.

PubMed Central

Tytell, Eric D; Ellington, Charles P

2003-01-01

The vortex wake structure of the hawkmoth, Manduca sexta, was investigated using a vortex ring generator. Based on existing kinematic and morphological data, a piston and tube apparatus was constructed to produce circular vortex rings with the same size and disc loading as a hovering hawkmoth. Results show that the artificial rings were initially laminar, but developed turbulence owing to azimuthal wave instability. The initial impulse and circulation were accurately estimated for laminar rings using particle image velocimetry; after the transition to turbulence, initial circulation was generally underestimated. The underestimate for turbulent rings can be corrected if the transition time and velocity profile are accurately known, but this correction will not be feasible for experiments on real animals. It is therefore crucial that the circulation and impulse be estimated while the wake vortices are still laminar. The scaling of the ring Reynolds number suggests that flying animals of about the size of hawkmoths may be the largest animals whose wakes stay laminar for long enough to perform such measurements during hovering. Thus, at low advance ratios, they may be the largest animals for which wake circulation and impulse can be accurately measured. PMID:14561347

Ontogenetic scaling of metabolism, growth, and assimilation: testing metabolic scaling theory with Manduca sexta larvae.

PubMed

Sears, Katie E; Kerkhoff, Andrew J; Messerman, Arianne; Itagaki, Haruhiko

2012-01-01

Metabolism, growth, and the assimilation of energy and materials are essential processes that are intricately related and depend heavily on animal size. However, models that relate the ontogenetic scaling of energy assimilation and metabolism to growth rely on assumptions that have yet to be rigorously tested. Based on detailed daily measurements of metabolism, growth, and assimilation in tobacco hornworms, Manduca sexta, we provide a first experimental test of the core assumptions of a metabolic scaling model of ontogenetic growth. Metabolic scaling parameters changed over development, in violation of the model assumptions. At the same time, the scaling of growth rate matches that of metabolic rate, with similar scaling exponents both across and within developmental instars. Rates of assimilation were much higher than expected during the first two instars and did not match the patterns of scaling of growth and metabolism, which suggests high costs of biosynthesis early in development. The rapid increase in size and discrete instars observed in larval insect development provide an ideal system for understanding how patterns of growth and metabolism emerge from fundamental cellular processes and the exchange of materials and energy between an organism and its environment.

Manduca sexta serpin-12 controls the prophenoloxidase activation system in larval hemolymph.

PubMed

Yang, Fan; Wang, Yang; Sumathipala, Niranji; Cao, Xiaolong; Kanost, Michael R; Jiang, Haobo

2018-08-01

Insect prophenoloxidase activation is coordinated by a serine protease network, which is regulated by serine protease inhibitors of the serpin superfamily. The enzyme system also leads to proteolytic processing of a Spätzle precursor. Binding of Spätzle to a Toll receptor turns on a signaling pathway to induce the synthesis of defense proteins. Previous studies of the tobacco hornworm Manduca sexta have revealed key members of the protease cascade, which generates phenoloxidase for melanogenesis and Spätzle to induce immunity-related genes. Here we provide evidence that M. sexta serpin-12 regulates hemolymph protease-14 (HP14), an initiating protease of the cascade. This inhibitor, unlike the other serpins characterized in M. sexta, has an amino-terminal extension rich in hydrophilic residues and an unusual P1 residue (Leu 429 ) right before the scissile bond cleaved by a target protease. Serpins with similarities to serpin-12, including Drosophila Necrotic, were identified in a wide range of insects including flies, moths, wasps, beetles, and two hemimetabolous species. The serpin-12 mRNA is present at low, constitutive levels in larval fat body and hemocytes and becomes more abundant after an immune challenge. We produced the serpin-12 core domain (serpin-12ΔN) in insect cells and in Escherichia coli and demonstrated its inhibition of human cathepsin G, bovine α-chymotrypsin, and porcine pancreatic elastase. MALDI-TOF analysis of the reaction mixtures confirmed the predicted P1 residue of Leu 429 . Supplementation of larval plasma samples with the serpin-12ΔN decreased prophenoloxidase activation elicited by microbial cells and reduced the proteolytic activation of the protease precursors of HP6, HP8, PAPs, and other serine protease-related proteins. After incubation of plasma stimulated with peptidoglycan, a 72 kDa protein appeared, which was recognized by polyclonal antibodies against both serpin-12 and HP14, suggesting that a covalent serpin-protease complex formed when serpin-12 inhibited HP14. Together, these data suggest that M. sexta serpin-12 inhibits HP14 to regulate melanization and antimicrobial peptide induction. Copyright © 2018 Elsevier Ltd. All rights reserved.

The HERBIVORE ELICITOR-REGULATED1 Gene Enhances Abscisic Acid Levels and Defenses against Herbivores in Nicotiana attenuata Plants1[C][W][OPEN

PubMed Central

Dinh, Son Truong; Baldwin, Ian T.; Galis, Ivan

2013-01-01

Nicotiana attenuata plants can distinguish the damage caused by herbivore feeding from other types of damage by perceiving herbivore-associated elicitors, such as the fatty acid-amino acid conjugates (FACs) in oral secretions (OS) of Manduca sexta larvae, which are introduced into wounds during feeding. However, the transduction of FAC signals into downstream plant defense responses is still not well established. We identified a novel FAC-regulated protein in N. attenuata (NaHER1; for herbivore elicitor regulated) and show that it is an indispensable part of the OS signal transduction pathway. N. attenuata plants silenced in the expression of NaHER1 by RNA interference (irHER1) were unable to amplify their defenses beyond basal, wound-induced levels in response to OS elicitation. M. sexta larvae performed 2-fold better when reared on irHER1 plants, which released less volatile organic compounds (indirect defense) and had strongly reduced levels of several direct defense metabolites, including trypsin proteinase inhibitors, 17-hydroxygeranyllinallool diterpene glycosides, and caffeoylputrescine, after real and/or simulated herbivore attack. In parallel to impaired jasmonate signaling and metabolism, irHER1 plants were more drought sensitive and showed reduced levels of abscisic acid (ABA) in the leaves, suggesting that silencing of NaHER1 interfered with ABA metabolism. Because treatment of irHER1 plants with ABA results in both the accumulation of significantly more ABA catabolites and the complete restoration of normal wild-type levels of OS-induced defense metabolites, we conclude that NaHER1 acts as a natural suppressor of ABA catabolism after herbivore attack, which, in turn, activates the full defense profile and resistance against herbivores. PMID:23784463

Insect parents improve the anti-parasitic and anti-bacterial defence of their offspring by priming the expression of immune-relevant genes.

PubMed

Trauer-Kizilelma, Ute; Hilker, Monika

2015-09-01

Insect parents that experienced an immune challenge are known to prepare (prime) the immune activity of their offspring for improved defence. This phenomenon has intensively been studied by analysing especially immunity-related proteins. However, it is unknown how transgenerational immune priming affects transcript levels of immune-relevant genes of the offspring upon an actual threat. Here, we investigated how an immune challenge of Manduca sexta parents affects the expression of immune-related genes in their eggs that are attacked by parasitoids. Furthermore, we addressed the question whether the transgenerational immune priming of expression of genes in the eggs is still traceable in adult offspring. Our study revealed that a parental immune challenge did not affect the expression of immune-related genes in unparasitised eggs. However, immune-related genes in parasitised eggs of immune-challenged parents were upregulated to a higher level than those in parasitised eggs of unchallenged parents. Hence, this transgenerational immune priming of the eggs was detected only "on demand", i.e. upon parasitoid attack. The priming effects were also traceable in adult female progeny of immune-challenged parents which showed higher transcript levels of several immune-related genes in their ovaries than non-primed progeny. Some of the primed genes showed enhanced expression even when the progeny was left unchallenged, whereas other genes were upregulated to a greater extent in primed female progeny than non-primed ones only when the progeny itself was immune-challenged. Thus, the detection of transgenerational immune priming strongly depends on the analysed genes and the presence or absence of an actual threat for the offspring. We suggest that M. sexta eggs laid by immune-challenged parents "afford" to upregulate the transcription of immunity-related genes only upon attack, because they have the chance to be endowed by parentally directly transferred protective proteins. Copyright © 2015 Elsevier Ltd. All rights reserved.

Detailed Characterization of Local Field Potential Oscillations and Their Relationship to Spike Timing in the Antennal Lobe of the Moth Manduca sexta

PubMed Central

Daly, Kevin C.; Galán, Roberto F.; Peters, Oakland J.; Staudacher, Erich M.

2011-01-01

The transient oscillatory model of odor identity encoding seeks to explain how odorants with spatially overlapped patterns of input into primary olfactory networks can be discriminated. This model provides several testable predictions about the distributed nature of network oscillations and how they control spike timing. To test these predictions, 16 channel electrode arrays were placed within the antennal lobe (AL) of the moth Manduca sexta. Unitary spiking and multi site local field potential (LFP) recordings were made during spontaneous activity and in response to repeated presentations of an odor panel. We quantified oscillatory frequency, cross correlations between LFP recording sites, and spike–LFP phase relationships. We show that odor-driven AL oscillations in Manduca are frequency modulating (FM) from ∼100 to 30 Hz; this was odorant and stimulus duration dependent. FM oscillatory responses were localized to one or two recording sites suggesting a localized (perhaps glomerular) not distributed source. LFP cross correlations further demonstrated that only a small (r < 0.05) distributed and oscillatory component was present. Cross spectral density analysis demonstrated the frequency of these weakly distributed oscillations was state dependent (spontaneous activity = 25–55 Hz; odor-driven = 55–85 Hz). Surprisingly, vector strength analysis indicated that unitary phase locking of spikes to the LFP was strongest during spontaneous activity and dropped significantly during responses. Application of bicuculline, a GABAA receptor antagonist, significantly lowered the frequency content of odor-driven distributed oscillatory activity. Bicuculline significantly reduced spike phase locking generally, but the ubiquitous pattern of increased phase locking during spontaneous activity persisted. Collectively, these results indicate that oscillations perform poorly as a stimulus-mediated spike synchronizing mechanism for Manduca and hence are incongruent with the transient oscillatory model. PMID:22046161

Sequence of a cDNA and expression of the gene encoding a putative epidermal chitin synthase of Manduca sexta.

PubMed

Zhu, Yu-Cheng; Specht, Charles A; Dittmer, Neal T; Muthukrishnan, Subbaratnam; Kanost, Michael R; Kramer, Karl J

2002-11-01

Glycosyltransferases are enzymes that synthesize oligosaccharides, polysaccharides and glycoconjugates. One type of glycosyltransferase is chitin synthase, a very important enzyme in biology, which is utilized by insects, fungi, and other invertebrates to produce chitin, a polysaccharide of beta-1,4-linked N-acetylglucosamine. Chitin is an important component of the insect's exoskeletal cuticle and gut lining. To identify and characterize a chitin synthase gene of the tobacco hornworm, Manduca sexta, degenerate primers were designed from two highly conserved regions in fungal and nematode chitin synthase protein sequences and then used to amplify a similar region from Manduca cDNA. A full-length cDNA of 5152 nucleotides was assembled for the putative Manduca chitin synthase gene, MsCHS1, and sequencing of genomic DNA verified the contiguity of the sequence. The MsCHS1 cDNA has an ORF of 4692 nucleotides that encodes a transmembrane protein of 1564 amino acid residues with a mass of approximately 179 kDa (GenBank no. AY062175). It is most similar, over its entire length of protein sequence, to putative chitin synthases from other insects and nematodes, with 68% identity to enzymes from both the blow fly, Lucilia cuprina, and the fruit fly, Drosophila melanogaster. The similarity with fungal chitin synthases is restricted to the putative catalytic domain, and the MsCHS1 protein has, at equivalent positions, several amino acids that are essential for activity as revealed by mutagenesis of the fungal enzymes. A 5.3-kb transcript of MsCHS1 was identified by northern blot hybridization of RNA from larval epidermis, suggesting that the enzyme functions to make chitin deposited in the cuticle. Further examination by RT-PCR showed that MsCHS1 expression is regulated in the epidermis, with the amount of transcript increasing during phases of cuticle deposition.

Localization of a GABA transporter to glial cells in the developing and adult olfactory pathway of the moth Manduca sexta1

PubMed Central

Oland, Lynne A; Gibson, Nicholas J; Tolbert, Leslie P

2010-01-01

Glial cells have several critical roles in the developing and adult olfactory (antennal) lobe of the moth Manduca sexta. Early in development, glial cells occupy discrete regions of the developing olfactory pathway and processes of GABAergic neurons extend into some of these regions. Because GABA is known to have developmental effects in a variety of systems, we explored the possibility that the glial cells express a GABA transporter that could regulate GABA levels to which olfactory neurons and glial cells are exposed. Using an antibody raised against a characterized high-affinity M. sexta GABA transporter with high sequence homology to known mammalian GABA transporters (Mbungu et al., 1995; Umesh and Gill, 2002), we found that the GABA transporter is localized to subsets of centrally derived glial cells during metamorphic adult development. The transporter persists into adulthood in a subset of the neuropil-associated glial cells, but its distribution pattern as determined by light- and electron-microscopic-level immunocytochemistry indicates that it could not serve to regulate GABA concentration in the synaptic cleft. Rather its role is more likely to regulate extracellular GABA levels within the glomerular neuropil. Expression in the sorting zone glial cells disappears after the period of olfactory receptor axon ingrowth, but may be important during ingrowth if GABA regulates axon growth. Glial cells take up GABA, and that uptake can be blocked by DABA. This is the first molecular evidence that the central glial cell population in this pathway is heterogeneous. PMID:20058309

A Simulation Environment for Aerodynamic Analysis and Design of Flapping Wing Micro Air Vehicles

DTIC Science & Technology

2010-01-01

parametric study involving numerous configurations with multiple flight conditions must be conducted in order to determine the potential "best design...virilis Honey Bee : Apis mellifica Bumble Bee : Bombus terrestris Hummingbird: Archi lochus colubris Hawkmoth: Manduca Sexta Hummingbird...Sf. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) B.PERFORMING ORGANIZATION REPORT NUMBER Streamline Numerics , Inc. SNI-CR

Flower tracking in hawkmoths: behavior and energetics.

PubMed

Sprayberry, Jordanna D H; Daniel, Thomas L

2007-01-01

As hovering feeders, hawkmoths cope with flower motions by tracking those motions to maintain contact with the nectary. This study examined the tracking, feeding and energetic performance of Manduca sexta feeding from flowers moving at varied frequencies and in different directions. In general we found that tracking performance decreased as frequency increased; M. sexta tracked flowers moving at 1 Hz best. While feeding rates were highest for stationary flowers, they remained relatively constant for all tested frequencies of flower motion. Calculations of net energy gain showed that energy expenditure to track flowers is minimal compared to energy intake; therefore, patterns of net energy gain mimicked patterns of feeding rate. The direction effects of flower motion were greater than the frequency effects. While M. sexta appeared equally capable of tracking flowers moving in the horizontal and vertical motion axes, they demonstrated poor ability to track flowers moving in the looming axis. Additionally, both feeding rates and net energy gain were lower for looming axis flower motions.

Wide-field motion tuning in nocturnal hawkmoths

PubMed Central

Theobald, Jamie C.; Warrant, Eric J.; O'Carroll, David C.

2010-01-01

Nocturnal hawkmoths are known for impressive visually guided behaviours in dim light, such as hovering while feeding from nectar-bearing flowers. This requires tight visual feedback to estimate and counter relative motion. Discrimination of low velocities, as required for stable hovering flight, is fundamentally limited by spatial resolution, yet in the evolution of eyes for nocturnal vision, maintenance of high spatial acuity compromises absolute sensitivity. To investigate these trade-offs, we compared responses of wide-field motion-sensitive neurons in three species of hawkmoth: Manduca sexta (a crepuscular hoverer), Deilephila elpenor (a fully nocturnal hoverer) and Acherontia atropos (a fully nocturnal hawkmoth that does not hover as it feeds uniquely from honey in bees' nests). We show that despite smaller eyes, the motion pathway of D. elpenor is tuned to higher spatial frequencies and lower temporal frequencies than A. atropos, consistent with D. elpenor's need to detect low velocities for hovering. Acherontia atropos, however, presumably evolved low-light sensitivity without sacrificing temporal acuity. Manduca sexta, active at higher light levels, is tuned to the highest spatial frequencies of the three and temporal frequencies comparable with A. atropos. This yields similar tuning to low velocities as in D. elpenor, but with the advantage of shorter neural delays in processing motion. PMID:19906663

Crystal structure of Manduca sexta prophenoloxidase provides insights into the mechanism of type 3 copper enzymes

PubMed Central

Li, Yongchao; Wang, Yang; Jiang, Haobo; Deng, Junpeng

2009-01-01

Arthropod phenoloxidase (PO) generates quinones and other toxic compounds to sequester and kill pathogens during innate immune responses. It is also involved in wound healing and other physiological processes. Insect PO is activated from its inactive precursor, prophenoloxidase (PPO), by specific proteolysis via a serine protease cascade. Here, we report the crystal structure of PPO from a lepidopteran insect at a resolution of 1.97 Å, which is the initial structure for a PPO from the type 3 copper protein family. Manduca sexta PPO is a heterodimer consisting of 2 homologous polypeptide chains, PPO1 and PPO2. The active site of each subunit contains a canonical type 3 di-nuclear copper center, with each copper ion coordinated with 3 structurally conserved histidines. The acidic residue Glu-395 located at the active site of PPO2 may serve as a general base for deprotonation of monophenolic substrates, which is key to the ortho-hydroxylase activity of PO. The structure provides unique insights into the mechanism by which type 3 copper proteins differ in their enzymatic activities, albeit sharing a common active center. A drastic change in electrostatic surface induced on cleavage at Arg-51 allows us to propose a model for localized PPO activation in insects. PMID:19805072

Inbreeding in horsenettle (Solanum carolinense) alters night-time volatile emissions that guide oviposition by Manduca sexta moths.

PubMed

Kariyat, Rupesh R; Mauck, Kerry E; Balogh, Christopher M; Stephenson, Andrew G; Mescher, Mark C; De Moraes, Consuelo M

2013-04-22

Plant volatiles serve as key foraging and oviposition cues for insect herbivores as well as their natural enemies, but little is known about how genetic variation within plant populations influences volatile-mediated interactions among plants and insects. Here, we explore how inbred and outbred plants from three maternal families of the native weed horsenettle (Solanum carolinense) vary in the emission of volatile organic compounds during the dark phase of the photoperiod, and the effects of this variation on the oviposition preferences of Manduca sexta moths, whose larvae are specialist herbivores of Solanaceae. Compared with inbred plants, outbred plants consistently released more total volatiles at night and more individual compounds-including some previously reported to repel moths and attract predators. Female moths overwhelmingly chose to lay eggs on inbred (versus outbred) plants, and this preference persisted when olfactory cues were presented in the absence of visual and contact cues. These results are consistent with our previous findings that inbred plants recruit more herbivores and suffer greater herbivory under field conditions. Furthermore, they suggest that constitutive volatiles released during the dark portion of the photoperiod can convey accurate information about plant defence status (and/or other aspects of host plant quality) to foraging herbivores.

Multiple alpha subunits of integrin are involved in cell-mediated responses of the Manduca immune system.

PubMed

Zhuang, Shufei; Kelo, Lisha; Nardi, James B; Kanost, Michael R

2008-01-01

The cell-mediated responses of the insect innate immune system-phagocytosis, nodulation, encapsulation-involve multiple cell adhesion molecules of hemocyte surfaces. A hemocyte-specific (HS) integrin and a member of the immunoglobulin (Ig) superfamily (neuroglian) are involved in the encapsulation response of hemocytes in Manduca sexta. In addition, two new integrin alpha (alpha) subunits have been found on these hemocytes. The alpha2 subunit is mainly expressed in epidermis and Malphigian tubules, whereas the alpha3 subunit is primarily expressed on hemocytes and fat body cells. Of the three known alpha subunits, the alpha1 subunit found in HS integrin is the predominant subunit of hemocytes. Cell adhesion assays indicate that alpha2 belongs to the integrin family with RGD-binding motifs, confirming the phylogenetic analysis of alpha subunits based on the amino-acid sequence alignment of different alpha subunits. Double-stranded RNAs (dsRNAs) targeting each of these three integrin alpha subunits not only specifically decreased transcript expression of each alpha subunit in hemocytes, but also abolished the cell-mediated encapsulation response of hemocytes to foreign surfaces. The individual alpha subunits of M. sexta integrins, like their integrin counterparts in mammalian immune systems, have critical, individual roles in cell-substrate and cell-cell interactions during immune responses.

Activation of epidermal growth factor receptor mediates receptor axon sorting and extension in the developing olfactory system of the moth Manduca sexta.

PubMed

Gibson, Nicholas J; Tolbert, Leslie P

2006-04-10

During development of the adult olfactory system of the moth Manduca sexta, olfactory receptor neurons extend axons from the olfactory epithelium in the antenna into the brain. As they arrive at the brain, interactions with centrally derived glial cells cause axons to sort and fasciculate with other axons destined to innervate the same glomeruli. Here we report studies indicating that activation of the epidermal growth factor receptor (EGFR) is involved in axon ingrowth and targeting. Blocking the EGFR kinase domain pharmacologically leads to stalling of many axons in the sorting zone and nerve layer as well as abnormal axonal fasciculation in the sorting zone. We also find that neuroglian, an IgCAM known to activate the EGFR through homophilic interactions in other systems, is transiently present on olfactory receptor neuron axons and on glia during the critical stages of the sorting process. The neuroglian is resistant to extraction with Triton X-100 in the sorting zone and nerve layer, possibly indicating its stabilization by homophilic binding in these regions. Our results suggest a mechanism whereby neuroglian molecules on axons and possibly sorting zone glia bind homophilically, leading to activation of EGFRs, with subsequent effects on axon sorting, pathfinding, and extension, and glomerulus development. Copyright 2006 Wiley-Liss, Inc.

Activation of EGF Receptor Mediates Receptor Axon Sorting and Extension in the Developing Olfactory System of the Moth Manduca sexta

PubMed Central

Gibson, Nicholas J.; Tolbert, Leslie P.

2008-01-01

During development of the adult olfactory system of the moth Manduca sexta, olfactory receptor neurons extend axons from the olfactory epithelium in the antenna into the brain. As they arrive at the brain, interactions with centrally-derived glial cells cause axons to sort and fasciculate with other axons destined to innervate the same glomeruli. Here we report studies that indicate that activation of the epidermal growth factor receptor (EGFR) is involved in axon ingrowth and targeting. Blocking the EGFR kinase domain pharmacologically leads to stalling of many axons in the sorting zone and nerve layer, as well as abnormal axonal fasciculation in the sorting zone. We also find that neuroglian, an IgCAM known to activate the EGFR through homophilic interactions in other systems, is transiently present on olfactory receptor neuron axons and on glia during the critical stages of the sorting process. The neuroglian is resistant to extraction with Triton X-100 in the sorting zone and nerve layer, possibly indicating its stabilization by homophilic binding in these regions. Our results suggest a mechanism whereby neuroglian molecules on axons and possibly sorting zone glia bind homophilically, leading to activation of EGFRs with subsequent effects on axon sorting, pathfinding, and extension, and glomerulus development. PMID:16498681

Mas-allatotropin in the developing antennal lobe of the sphinx moth Manduca sexta: distribution, time course, developmental regulation, and colocalization with other neuropeptides.

PubMed

Utz, Sandra; Huetteroth, Wolf; Vömel, Matthias; Schachtner, Joachim

2008-01-01

The paired antennal lobes (ALs) of the sphinx moth Manduca sexta serve as a well-established model for studying development of the primary integration centers for odor information in the brain. To further reveal the role of neuropeptides during AL development, we have analyzed cellular distribution, developmental time course, and regulation of the neuropeptide M. sexta allatotropin (Mas-AT). On the basis of morphology and appearance during AL formation, seven major types of Mas-AT-immunoreactive (ir) cells could be distinguished. Mas-AT-ir cells are identified as local, projection, and centrifugal neurons, which are either persisting larval or newly added adult-specific neurons. Complementary immunostaining with antisera against two other neuropeptide families (A-type allatostatins, RFamides) revealed colocalization within three of the Mas-AT-ir cell types. On the basis of this neurochemistry, the most prominent type of Mas-AT-ir neurons, the local AT neurons (LATn), could be divided in three subpopulations. The appearance of the Mas-AT-ir cell types occurring during metamorphosis parallels the rising titer of the developmental hormone 20-hydroxyecdysone (20E). Artificially shifting the 20E titer to an earlier developmental time point resulted in the precocious occurrence of Mas-AT immunostaining. This result supports the hypothesis that the pupal rise of 20E is causative for Mas-AT expression during AL development. Comparing localization and developmental time course of Mas-AT and other neuropeptides with the time course of AL formation suggests various functions for these neuropeptides during development, including an involvement in the formation of the olfactory glomeruli.

Electroantennographic and behavioral responses of the sphinx moth Manduca sexta to host plant headspace volatiles.

PubMed

Fraser, Ann M; Mechaber, Wendy L; Hildebrand, John G

2003-08-01

Coupled gas chromatography with electroantennographic detection (GC-EAD) using antennae of adult female Manduca sexta was employed to screen for olfactory stimulants present in headspace collections from four species of larval host plants belonging to two families: Solanaceae--Lycopersicon esculentum (tomato), Capiscum annuum (bell pepper), and Datura wrightii; and Martyniaceae--Pronboscideaparviflora. Headspace volatiles were collected from undamaged foliage of potted, living plants. GC-EAD revealed 23 EAD-active compounds, of which 15 were identified by GC-mass spectrometry. Identified compounds included aliphatic, aromatic, and terpenoid compounds bearing a range of functional groups. Nine EAD-active compounds were common to all four host plant species: (Z)-3-hexenyl acetate, nonanal, decanal, phenylacetaldehyde, methyl salicylate, benzyl alcohol, geranyl acetone, (E)-nerolidol, and one unidentified compound. Behavioral responses of female moths to an eight-component synthetic blend of selected tomato headspace volatiles were tested in a laboratory wind tunnel. Females were attracted to the blend. A comparison of responses from antennae of males and females to bell pepper headspace volatiles revealed that males responded to the same suite of volatiles as females, except for (Z)-3-hexenyl benzoate. EAD responses of males also were lower for (Z)-and (E)-nerolidol and one unidentified compound. Electroantennogram EAG dose-response curves for the 15 identified EAD-active volatiles were recorded. At the higher test doses (10-100 microg), female antennae yielded larger EAG responses to terpenoids and to aliphatic and aromatic esters. Male antennae did respond to the higher doses of (Z)-3-hexenyl benzoate, indicating that they can detect this compound. On the basis of ubiquity of the EAD-active volatiles identified to date in host plant headspace collections, we suggest that M. sexta uses a suite of volatiles to locate and identify appropriate host plants.

Biological Investigation of the Stimulated Flapping Motions of the Moth, Manduca sexta

DTIC Science & Technology

2011-03-01

the sites of toxic chemical spills or damaged nuclear reactors (Alexander, 2002). Dr. Mark Reeder, Editor-in-Chief of the International Journal...Process The overall objective of research, using bio -inspired technology and techniques, is to develop clear scientific understanding about some of...it in a small container and submerging it in a bucket of ice for approximately 15 minutes, until the moth was unresponsive to stimulation.  Under

Characterisation of the Manduca sexta sperm proteome: Genetic novelty underlying sperm composition in Lepidoptera.

PubMed

Whittington, Emma; Zhao, Qian; Borziak, Kirill; Walters, James R; Dorus, Steve

2015-07-01

The application of mass spectrometry based proteomics to sperm biology has greatly accelerated progress in understanding the molecular composition and function of spermatozoa. To date, these approaches have been largely restricted to model organisms, all of which produce a single sperm morph capable of oocyte fertilisation. Here we apply high-throughput mass spectrometry proteomic analysis to characterise sperm composition in Manduca sexta, the tobacco hornworm moth, which produce heteromorphic sperm, including one fertilisation competent (eupyrene) and one incompetent (apyrene) sperm type. This resulted in the high confidence identification of 896 proteins from a co-mixed sample of both sperm types, of which 167 are encoded by genes with strict one-to-one orthology in Drosophila melanogaster. Importantly, over half (55.1%) of these orthologous proteins have previously been identified in the D. melanogaster sperm proteome and exhibit significant conservation in quantitative protein abundance in sperm between the two species. Despite the complex nature of gene expression across spermatogenic stages, a significant correlation was also observed between sperm protein abundance and testis gene expression. Lepidopteran-specific sperm proteins (e.g., proteins with no homology to proteins in non-Lepidopteran taxa) were present in significantly greater abundance on average than those with homology outside the Lepidoptera. Given the disproportionate production of apyrene sperm (96% of all mature sperm in Manduca) relative to eupyrene sperm, these evolutionarily novel and highly abundant proteins are candidates for possessing apyrene-specific functions. Lastly, comparative genomic analyses of testis-expressed, ovary-expressed and sperm genes identified a concentration of novel sperm proteins shared amongst Lepidoptera of potential relevance to the evolutionary origin of heteromorphic spermatogenesis. As the first published Lepidopteran sperm proteome, this whole-cell proteomic characterisation will facilitate future evolutionary genetic and developmental studies of heteromorphic sperm production and parasperm function. Furthermore, the analyses presented here provide useful annotation information regarding sex-biased gene expression, novel Lepidopteran genes and gene function in the male gamete to complement the newly sequenced and annotated Manduca genome. Copyright © 2015 Elsevier Ltd. All rights reserved.

SuperSAGE analysis of the Nicotiana attenuata transcriptome after fatty acid-amino acid elicitation (FAC): identification of early mediators of insect responses

PubMed Central

2010-01-01

Background Plants trigger and tailor defense responses after perception of the oral secretions (OS) of attacking specialist lepidopteran larvae. Fatty acid-amino acid conjugates (FACs) in the OS of the Manduca sexta larvae are necessary and sufficient to elicit the herbivory-specific responses in Nicotiana attenuata, an annual wild tobacco species. How FACs are perceived and activate signal transduction mechanisms is unknown. Results We used SuperSAGE combined with 454 sequencing to quantify the early transcriptional changes elicited by the FAC N-linolenoyl-glutamic acid (18:3-Glu) and virus induced gene silencing (VIGS) to examine the function of candidate genes in the M. sexta-N. attenuata interaction. The analysis targeted mRNAs encoding regulatory components: rare transcripts with very rapid FAC-elicited kinetics (increases within 60 and declines within 120 min). From 12,744 unique Tag sequences identified (UniTags), 430 and 117 were significantly up- and down-regulated ≥ 2.5-fold, respectively, after 18:3-Glu elicitation compared to wounding. Based on gene ontology classification, more than 25% of the annotated UniTags corresponded to putative regulatory components, including 30 transcriptional regulators and 22 protein kinases. Quantitative PCR analysis was used to analyze the FAC-dependent regulation of a subset of 27 of these UniTags and for most of them a rapid and transient induction was confirmed. Six FAC-regulated genes were functionally characterized by VIGS and two, a putative lipid phosphate phosphatase (LPP) and a protein of unknown function, were identified as important mediators of the M. sexta-N. attenuata interaction. Conclusions The analysis of the early changes in the transcriptome of N. attenuata after FAC elicitation using SuperSAGE/454 has identified regulatory genes involved in insect-specific mediated responses in plants. Moreover, it has provided a foundation for the identification of additional novel regulators associated with this process. PMID:20398280

SuperSAGE analysis of the Nicotiana attenuata transcriptome after fatty acid-amino acid elicitation (FAC): identification of early mediators of insect responses.

PubMed

Gilardoni, Paola A; Schuck, Stefan; Jüngling, Ruth; Rotter, Björn; Baldwin, Ian T; Bonaventure, Gustavo

2010-04-14

Plants trigger and tailor defense responses after perception of the oral secretions (OS) of attacking specialist lepidopteran larvae. Fatty acid-amino acid conjugates (FACs) in the OS of the Manduca sexta larvae are necessary and sufficient to elicit the herbivory-specific responses in Nicotiana attenuata, an annual wild tobacco species. How FACs are perceived and activate signal transduction mechanisms is unknown. We used SuperSAGE combined with 454 sequencing to quantify the early transcriptional changes elicited by the FAC N-linolenoyl-glutamic acid (18:3-Glu) and virus induced gene silencing (VIGS) to examine the function of candidate genes in the M. sexta-N. attenuata interaction. The analysis targeted mRNAs encoding regulatory components: rare transcripts with very rapid FAC-elicited kinetics (increases within 60 and declines within 120 min). From 12,744 unique Tag sequences identified (UniTags), 430 and 117 were significantly up- and down-regulated >or= 2.5-fold, respectively, after 18:3-Glu elicitation compared to wounding. Based on gene ontology classification, more than 25% of the annotated UniTags corresponded to putative regulatory components, including 30 transcriptional regulators and 22 protein kinases. Quantitative PCR analysis was used to analyze the FAC-dependent regulation of a subset of 27 of these UniTags and for most of them a rapid and transient induction was confirmed. Six FAC-regulated genes were functionally characterized by VIGS and two, a putative lipid phosphate phosphatase (LPP) and a protein of unknown function, were identified as important mediators of the M. sexta-N. attenuata interaction. The analysis of the early changes in the transcriptome of N. attenuata after FAC elicitation using SuperSAGE/454 has identified regulatory genes involved in insect-specific mediated responses in plants. Moreover, it has provided a foundation for the identification of additional novel regulators associated with this process.

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.

Influence of Temperature on the Physiology and Virulence of the Insect Pathogen Serratia sp. Strain SCBI

PubMed Central

Petersen, Lauren M.

2012-01-01

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

Early Metamorphic Insertion Technology for Insect Flight Behavior Monitoring

PubMed Central

Bozkurt, Alper

2014-01-01

Early Metamorphosis Insertion Technology (EMIT) is a novel methodology for integrating microfabricated neuromuscular recording and actuation platforms on insects during their metamorphic development. Here, the implants are fused within the structure and function of the neuromuscular system as a result of metamorphic tissue remaking. The implants emerge with the insect where the development of tissue around the electronics during pupal development results in a bioelectrically and biomechanically enhanced tissue interface. This relatively more reliable and stable interface would be beneficial for many researchers exploring the neural basis of the insect locomotion with alleviated traumatic effects caused during adult stage insertions. In this article, we implant our electrodes into the indirect flight muscles of Manduca sexta. Located in the dorsal-thorax, these main flight powering dorsoventral and dorsolongitudinal muscles actuate the wings and supply the mechanical power for up and down strokes. Relative contraction of these two muscle groups has been under investigation to explore how the yaw maneuver is neurophysiologically coordinated. To characterize the flight dynamics, insects are often tethered with wires and their flight is recorded with digital cameras. We also developed a novel way to tether Manduca sexta on a magnetically levitating frame where the insect is connected to a commercially available wireless neural amplifier. This set up can be used to limit the degree of freedom to yawing “only” while transmitting the related electromyography signals from dorsoventral and dorsolongitudinal muscle groups. PMID:25079130

Effect of body aerodynamics on the dynamic flight stability of the hawkmoth Manduca sexta.

PubMed

Nguyen, Anh Tuan; Han, Jong-Seob; Han, Jae-Hung

2016-12-14

This study explores the effects of the body aerodynamics on the dynamic flight stability of an insect at various different forward flight speeds. The insect model, whose morphological parameters are based on measurement data from the hawkmoth Manduca sexta, is treated as an open-loop six-degree-of-freedom dynamic system. The aerodynamic forces and moments acting on the insect are computed by an aerodynamic model that combines the unsteady panel method and the extended unsteady vortex-lattice method. The aerodynamic model is then coupled to a multi-body dynamic code to solve the system of motion equations. First, the trimmed flight conditions of insect models with and without consideration of the body aerodynamics are obtained using a trim search algorithm. Subsequently, the effects of the body aerodynamics on the dynamic flight stability are analysed through modal structures, i.e., eigenvalues and eigenvectors in this case, which are based on linearized equations of motion. The solutions from the nonlinear and linearized equations of motion due to gust disturbances are obtained, and the effects of the body aerodynamics are also investigated through these solutions. The results showed the important effect of the body aerodynamics at high-speed forward flight (in this paper at 4.0 and 5.0 m s -1 ) and the movement trends of eigenvalues when the body aerodynamics is included.

Evaluation of the Thorax of Manduca sexta for Flapping Wing Micro Air Vehicle Applications

DTIC Science & Technology

2012-03-01

input (Pi) by the muscle efficiency (Em). Estimates for muscular efficiency in insects are based on measurements of oxygen consumption which can be...34 Effects of Operating Frequency and Temperature on Mechanical Power Output form Moth Flight Muscle." Journal of Experimental Biology 149 (1990): 61...they will teach you, or the birds in the sky, and they will tell you; or speak to the earth, and it will teach you, or let the fish in the sea inform

Identification of a CAPA-PVK (IXORI-PVK) from Single Cells of the Gulf Coast Tick, Amblyomma maculatum

DTIC Science & Technology

2008-01-01

neurons of the abdominal ganglia and are likely to be released as hormones from the abdominal perisympatic organs ( PSOs ) into the hemolymph. The...CAPs) in the VNC/ PSOs of the tobacco hawk moth, Manduca sexta. Indeed, in a recent study we have identified the first peptidergic neurohormone from...discussions on the manuscript. REFERENCES [1] Coast G.M., Garside C.S., Ann . NY Acad Sci., 2005, 1040,1-8. [2] Pietrantonio P.V., Jagge C., Taneja

No Evidence for Ionotropic Pheromone Transduction in the Hawkmoth Manduca sexta.

PubMed

Nolte, Andreas; Gawalek, Petra; Koerte, Sarah; Wei, HongYing; Schumann, Robin; Werckenthin, Achim; Krieger, Jürgen; Stengl, Monika

2016-01-01

Insect odorant receptors (ORs) are 7-transmembrane receptors with inverse membrane topology. They associate with the conserved ion channel Orco. As chaperon, Orco maintains ORs in cilia and, as pacemaker channel, Orco controls spontaneous activity in olfactory receptor neurons. Odorant binding to ORs opens OR-Orco receptor ion channel complexes in heterologous expression systems. It is unknown, whether this also occurs in vivo. As an alternative to this ionotropic transduction, experimental evidence is accumulating for metabotropic odor transduction, implicating that insect ORs couple to G-proteins. Resulting second messengers gate various ion channels. They generate the sensillum potential that elicits phasic-tonic action potentials (APs) followed by late, long-lasting pheromone responses. Because it is still unclear how and when Orco opens after odor-OR-binding, we used tip recordings to examine in vivo the effects of the Orco antagonist OLC15 and the amilorides MIA and HMA on bombykal transduction in the hawkmoth Manduca sexta. In contrast to OLC15 both amilorides decreased the pheromone-dependent sensillum potential amplitude and the frequency of the phasic AP response. Instead, OLC15 decreased spontaneous activity, increased latencies of phasic-, and decreased frequencies of late, long-lasting pheromone responses Zeitgebertime-dependently. Our results suggest no involvement for Orco in the primary transduction events, in contrast to amiloride-sensitive channels. Instead of an odor-gated ionotropic receptor, Orco rather acts as a voltage- and apparently second messenger-gated pacemaker channel controlling the membrane potential and hence threshold and kinetics of the pheromone response.

Dietary nutrient levels regulate protein and carbohydrate intake, gluconeogenic/glycolytic flux and blood trehalose level in the insect Manduca sexta L.

PubMed

Thompson, S N; Borchardt, D B; Wang, L-W

2003-03-01

This study examined the effects of dietary casein and sucrose levels on nutrient intake, and distinguished the effects of carbohydrate and protein consumption on growth, fat content, pyruvate metabolism and blood trehalose level of 5th instar Manduca sexta larvae. Growth increased with increasing casein consumption but was unaffected by carbohydrate intake. Fat content also increased with carbohydrate consumption, but on carbohydrate-free diets fat content increased with increased protein consumption. Blood trehalose level and pyruvate metabolism were examined by nuclear magnetic resonance spectroscopy analysis of blood following administration of (3-(13)C)pyruvate. On diets containing sucrose, blood trehalose increased with increasing carbohydrate intake, and on most diets trehalose was synthesized entirely from dietary sucrose. Pyruvate cycling, indicated by the alanine C2/C3 (13)C enrichment ratio, increased with carbohydrate consumption reflecting increased glycolysis, and pyruvate decarboxylation exceeded carboxylation on all sucrose diets. Larvae that consumed <75 mg/day sucrose were gluconeogenic, based on the [2 (trehalose C6)(Glx C3/C2)]/alanine C2] (13)C enrichment ratio. On carbohydrate-free diets, blood trehalose levels were low and maintained entirely by gluconeogenesis. Blood trehalose level increased with increasing protein intake. Pyruvate cycling was very low, although many insects displayed higher levels of pyruvate decarboxylation than carboxylation. All gluconeogenic larvae displayed alanine (13)C enrichment ratios <0.35 and had blood trehalose levels <50 mM.

Serpin-9 and -13 regulate hemolymph proteases during immune responses of Manduca sexta.

PubMed

He, Yan; Wang, Yang; Zhao, Picheng; Rayaprolu, Subrahmanyam; Wang, Xiuhong; Cao, Xiaolong; Jiang, Haobo

2017-11-01

Serpins are a superfamily of proteins, most of which inhibit cognate serine proteases by forming inactive acyl-enzyme complexes. In the tobacco hornworm Manduca sexta, serpin-1, -3 through -7 negatively regulate a hemolymph serine protease system that activates precursors of the serine protease homologs (SPHs), phenoloxidases (POs), Spätzles, and other cytokines. Here we report the cloning and characterization of M. sexta serpin-9 and -13. Serpin-9, a 402-residue protein most similar to Drosophila Spn77Ba, has R 366 at the P1 position right before the cleavage site; Serpin-13, a 444-residue ortholog of Drosophila Spn28Dc, is longer than the other seven serpins and has R 410 as the P1 residue. Both serpins are mainly produced in fat body and secreted into plasma to function. While their mRNA and protein levels were not up-regulated upon immune challenge, they blocked protease activities and affected proPO activation in hemolymph. Serpin-9 inhibited human neutrophil elastase, cathepsin G, trypsin, and chymotrypsin to different extents; serpin-13 reduced trypsin activity to approximately 10% at a molar ratio of 4:1 (serpin: enzyme). Serpin-9 was cleaved at Arg 366 by the enzymes with different specificity, but serpin-13 had four P1 sites (Arg 410 for trypsin-like proteases, Gly 406 and Ala 409 for the elastase and Thr 404 for cathepsin G). Supplementation of induced cell-free hemolymph (IP, P for plasma) with recombinant serpin-9 did not noticeably affect proPO activation, but slightly reduced the PO activity increase after 0-50% ammonium sulfate fraction of the IP had been elicited by bacteria. In comparison, addition of recombinant serpin-13 significantly inhibited proPO activation in IP and the suppression was stronger in the fraction of IP. Serpin-9- and -13-containing protein complexes were isolated from IP using their antibodies. Hemolymph protease-1 precursor (proHP1), HP6 and HP8 were found to be associated with serpin-9, whereas proHP1, HP2 and HP6 were pulled downed with serpin-13. These results indicate that both serpins regulate immune proteases in hemolymph of M. sexta larvae. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Characterization of Material Properties and Structural Dynamics of the Manduca Sexta Forewing for Application to Flapping Wing Micro Air Vehicle Design

DTIC Science & Technology

2012-09-13

2.1.1 Wing Morphology. Insect wings are formed from a complex makeup of polymer based chains, Chitin , that form the Cuticle, which provides the strong... Chitin , a long-chain polymer and a deriva- tive of glucose, is the main component of the exoskeletons and wings of insects . Due to the ability of the...biological specimen to vary the bonding chains, assemblage of nanofibers, and crystalline structure, the material properties of chitin can vary over a

Negative regulation of prophenoloxidase (proPO) activation by a clip-domain serine proteinase homolog (SPH) from endoparasitoid venom.

PubMed

Zhang, Guangmei; Lu, Zhi-Qiang; Jiang, Haobo; Asgari, Sassan

2004-05-01

Most parasitic wasps inject maternal factors into the host hemocoel to suppress the host immune system and ensure successful development of their progeny. Melanization is one of the insect defence mechanisms against intruding pathogens or parasites. We previously isolated from the venom of Cotesia rubecula a 50 kDa protein that blocked melanization in the hemolymph of its host, Pieris rapae [Insect Biochem. Mol. Biol. 33 (2003) 1017]. This protein, designated Vn50, is a serine proteinase homolog (SPH) containing an amino-terminal clip domain. In this work, we demonstrated that recombinant Vn50 bound P. rapae hemolymph components that were recognized by antisera to Tenebrio molitor prophenoloxidase (proPO) and Manduca sexta proPO-activating proteinase (PAP). Vn50 is stable in the host hemolymph-it remained intact for at least 72 h after parasitization. Using M. sexta as a model system, we found that Vn50 efficiently down-regulated proPO activation mediated by M. sexta PAP-1, SPH-1, and SPH-2. Vn50 did not inhibit active phenoloxidase (PO) or PAP-1, but it significantly reduced the proteolysis of proPO. If recombinant Vn50 binds P. rapae proPO and PAP (as suggested by the antibody reactions), it is likely that the molecular interactions among M. sexta proPO, PAP-1, and SPHs were impaired by this venom protein. A similar strategy might be employed by C. rubecula to negatively impact the proPO activation reaction in its natural host.

Segmentally distributed metamorphic changes in neural circuits controlling abdominal bending in the hawk moth Manduca sexta.

PubMed

Lemon, W C; Levine, R B

1997-06-01

During the metamorphosis of Manduca sexta the larval nervous system is reorganized to allow the generation of behaviors that are specific to the pupal and adult stages. In some instances, metamorphic changes in neurons that persist from the larval stage are segment-specific and lead to expression of segment-specific behavior in later stages. At the larval-pupal transition, the larval abdominal bending behavior, which is distributed throughout the abdomen, changes to the pupal gin trap behavior which is restricted to three abdominal segments. This study suggests that the neural circuit that underlies larval bending undergoes segment specific modifications to produce the segmentally restricted gin trap behavior. We show, however, that non-gin trap segments go through a developmental change similar to that seen in gin trap segments. Pupal-specific motor patterns are produced by stimulation of sensory neurons in abdominal segments that do not have gin traps and cannot produce the gin trap behavior. In particular, sensory stimulation in non-gin trap pupal segments evokes a motor response that is faster than the larval response and that displays the triphasic contralateral-ipsilateral-contralateral activity pattern that is typical of the pupal gin trap behavior. Despite the alteration of reflex activity in all segments, developmental changes in sensory neuron morphology are restricted to those segments that form gin traps. In non-gin trap segments, persistent sensory neurons do not expand their terminal arbors, as do sensory neurons in gin trap segments, yet are capable of eliciting gin trap-like motor responses.

Phylogenetic analysis and expression profiling of the pattern recognition receptors: Insights into molecular recognition of invading pathogens in Manduca sexta.

PubMed

Zhang, Xiufeng; He, Yan; Cao, Xiaolong; Gunaratna, Ramesh T; Chen, Yun-ru; Blissard, Gary; Kanost, Michael R; Jiang, Haobo

2015-07-01

Pattern recognition receptors (PRRs) detect microbial pathogens and trigger innate immune responses. Previous biochemical studies have elucidated the physiological functions of eleven PRRs in Manduca sexta but our understanding of the recognition process is still limited, lacking genomic perspectives. While 34 C-type lectin-domain proteins and 16 Toll-like receptors are reported in the companion papers, we present here 120 other putative PRRs identified through the genome annotation. These include 76 leucine-rich repeat (LRR) proteins, 14 peptidoglycan recognition proteins, 6 EGF/Nim-domain proteins, 5 β-1,3-glucanase-related proteins, 4 galectins, 4 fibrinogen-related proteins, 3 thioester proteins, 5 immunoglobulin-domain proteins, 2 hemocytins, and 1 Reeler. Sequence alignment and phylogenetic analysis reveal the evolution history of a diverse repertoire of proteins for pathogen recognition. While functions of insect LRR proteins are mostly unknown, their structure diversification is phenomenal: In addition to the Toll homologs, 22 LRR proteins with a signal peptide are expected to be secreted; 18 LRR proteins lacking signal peptides may be cytoplasmic; 36 LRRs with a signal peptide and a transmembrane segment may be non-Toll receptors on the surface of cells. Expression profiles of the 120 genes in 52 tissue samples reflect complex regulation in various developmental stages and physiological states, including some likely by Rel family transcription factors via κB motifs in the promoter regions. This collection of information is expected to facilitate future biochemical studies detailing their respective roles in this model insect. Copyright © 2015 Elsevier Ltd. All rights reserved.

Phylogenetic analysis and expression profiling of the pattern recognition receptors: insights into molecular recognition of invading pathogens in Manduca sexta

PubMed Central

Zhang, Xiufeng; He, Yan; Cao, Xiaolong; Gunaratna, Ramesh T.; Chen, Yun-ru; Blissard, Gary; Kanost, Michael R.; Jiang, Haobo

2015-01-01

Pattern recognition receptors (PRRs) detect microbial pathogens and trigger innate immune responses. Previous biochemical studies have elucidated the physiological functions of eleven PRRs in Manduca sexta but our understanding of the recognition process is still limited, lacking genomic perspectives. While 34 C-type lectin-domain proteins and 16 Toll-like receptors are reported in the companion papers, we present here 120 other putative PRRs identified through the genome annotation. These include 76 leucine-rich repeat (LRR) proteins, 14 peptidoglycan recognition proteins, 6 EGF/Nim-domain proteins, 5 β-1,3-glucanase-related proteins, 4 galectins, 4 fibrinogen-related proteins, 3 thioester proteins, 5 immunoglobulin-domain proteins, 2 hemocytins, and 1 Reeler. Sequence alignment and phylogenetic analysis reveal the evolution history of a diverse repertoire of proteins for pathogen recognition. While functions of insect LRR proteins are mostly unknown, their structure diversification is phenomenal: In addition to the Toll homologs, 22 LRR proteins with a signal peptide are expected to be secreted; 18 LRR proteins lacking signal peptides may be cytoplasmic; 36 LRRs with a signal peptide and a transmembrane segment may be non-Toll receptors on the surface of cells. Expression profiles of the 120 genes in 52 tissue samples reflect complex regulation in various developmental stages and physiological states, including some likely by Rel family transcription factors via κB motifs in the promoter regions. This collection of information is expected to facilitate future biochemical studies detailing their respective roles in this model insect. PMID:25701384

Utilization of [14C]phenylalanine derived from arylphorin or free amino acid in Manduca sexta pharate adults

NASA Technical Reports Server (NTRS)

Wu, M.; Tischler, M. E.

1995-01-01

The role of arylphorin as a storage protein was studied using 14C-arylphorin. 14C-arylphorin was produced optimally by incubating one-half fat body from Manduca sexta fifth instar larvae at 22 degrees C for 24 h, in 1 ml of medium containing amino acids at 25% of their physiological concentration with [U-14C]-phenylalanine (phe) provided initially without nonlabeled phenylalanine. Nonlabeled phe was provided after 1 h at 16% of its physiological concentration. The specific activity of 14C-arylphorin produced in vitro was 30 times greater than that generated in vivo. Injection of 14C-arylphorin into pharate adults was used to study the distribution of 14C-phe derived from this protein into 14CO2 and tissues for comparison with injection of free 14C-phe during the middle (days 6 to 12 pharate adult) and late (days 12 to 17 pharate adult) stages of adult development. Appearance of 14CO2 from 14C-arylphorin as compared to 14C-phenylalanine showed a slower time course during both the middle and late stages of development, in keeping with the time needed for degradation of the protein. In accord with faster phe turnover near the end of adult development, total 14CO2 production was greater and the retention of 14C in hemolymph and fat body was less compared to the middle stage of development regardless of whether 14C-arylphorin or 14C-phe was injected. In the middle stage of development, the appearance of 14C in the cuticle and head parts was greater, whereas incorporation into abdomen and thorax was less than during the late stage of development. Since the pattern of 14C distribution from 14C-arylphorin and 14C-phe was similar, one major function of arylphorin must be as a storage protein replenishing the supply of free amino acids used for synthesis of adult tissues. These results also suggest a limited contribution of M. sexta arylphorin to formation of the cuticle subsequent to day-6 pharate adult.

Recent Advances in Insect Olfaction, Specifically Regarding the Morphology and Sensory Physiology of Antennal Sensilla of the Female Sphinx Moth Manduca sexta

PubMed Central

SHIELDS, VONNIE D.C.; HILDEBRAND, JOHN G.

2008-01-01

The antennal flagellum of female Manduca sexta bears eight sensillum types: two trichoid, two basiconic, one auriculate, two coeloconic, and one styliform complex sensilla. The first type of trichoid sensillum averages 34 μm in length and is innervated by two sensory cells. The second type averages 26 μm in length and is innervated by either one or three sensory cells. The first type of basiconic sensillum averages 22 μm in length, while the second type averages 15 μm in length. Both types are innervated by three bipolar sensory cells. The auriculate sensillum averages 4 μm in length and is innervated by two bipolar sensory cells. The coeloconic type-A and type-B both average 2 μm in length. The former type is innervated by five bipolar sensory cells, while the latter type, by three bipolar sensory cells. The styliform complex sensillum occurs singly on each annulus and averages 38-40 μm in length. It is formed by several contiguous sensilla. Each unit is innervated by three bipolar sensory cells. A total of 2,216 sensilla were found on a single annulus (annulus 21) of the flagellum. Electrophysiological responses from type-A trichoid sensilla to a large panel of volatile odorants revealed three different subsets of olfactory receptor cells (ORCs). Two subsets responded strongly to only a narrow range of odorants, while the third responded strongly to a broad range of odorants. Anterograde labeling of ORCs from type-A trichoid sensilla revealed that their axons projected mainly to two large female glomeruli of the antennal lobe. PMID:11754510

Development of A-type allatostatin immunoreactivity in antennal lobe neurons of the sphinx moth Manduca sexta.

PubMed

Utz, Sandra; Schachtner, Joachim

2005-04-01

The antennal lobe (AL) of the sphinx moth Manduca sexta is a well-established model system for studying mechanisms of neuronal development. To understand whether neuropeptides are suited to playing a role during AL development, we have studied the cellular localization and temporal expression pattern of neuropeptides of the A-type allatostatin family. Based on morphology and developmental appearance, we distinguished four types of AST-A-immunoreactive cell types. The majority of the cells were local interneurons of the AL (type Ia) which acquired AST-A immunostaining in a complex pattern consisting of three rising (RI-RIII) and two declining phases (DI, DII). Type Ib neurons consisted of two local neurons with large cell bodies not appearing before 7/8 days after pupal ecdysis (P7/P8). Types II and III neurons accounted for single centrifugal neurons, with type II neurons present in the larva and disappearing in the early pupa. The type III neuron did not appear before P7/P8. RI and RII coincided with the rises of the ecdysteroid hemolymph titer. Artificially shifting the pupal 20-hydroxyecdysone (20E) peak to an earlier developmental time point resulted in the precocious appearance of AST-A immunostaining in types Ia, Ib, and III neurons. This result supports the hypothesis that the pupal rise in 20E plays a role in AST-A expression during AL development. Because of their early appearance in newly forming glomeruli, AST-A-immunoreactive fibers could be involved in glomerulus formation. Diffuse AST-A labeling during early AL development is discussed as a possible signal providing information for ingrowing olfactory receptor neurons.

Immunocytochemical localization of choline acetyltransferase and muscarinic ACh receptors in the antenna during development of the sphinx moth Manduca sexta.

PubMed

Clark, Julie; Meisner, Shannon; Torkkeli, Päivi H

2005-04-01

Immunocytochemistry with monoclonal antibodies was used to investigate the locations of muscarinic acetylcholine receptors (mAChR) and choline acetyltransferase (ChAT) in sections of the developing antennae of the moth Manduca sexta. The results were correlated with a previous morphological investigation in the developing antennae which allowed us to locate different cell types at various stages of development. Our findings indicated that the muscarinic cholinergic system was not restricted to the sensory neurons but was also present in glial and epidermal cells. By day 4-5 of adult development, immunoreactivity against both antibodies was present in the axons of the antennal nerve, and more intense labeling was present in sections from older pupae. At days 4-9, the cell bodies of the sensory neurons in the basal part of the epidermis were also intensely immunolabeled by the anti-mAChR antibody. In mature flagella, large numbers of cells, some with processes into hairs, were strongly labeled by both antibodies. Antennal glial cells were intensely immunolabeled with both antibodies by days 4-5, but in later stages, it was not possible to discriminate between glial and neural staining. At days 4-9, we observed a distinctly labeled layer of epidermal cells close to the developing cuticle. The expression of both ChAT and mAChRs by neurons in moth antennae may allow the regulation of excitability by endogenous ACh. Cholinergic communication between neurons and glia may be part of the system that guides axon elongation during development. The cholinergic system in the apical part of the developing epidermis could be involved in cuticle formation.

Gyroscopic sensing in the wings of the hawkmoth Manduca sexta: the role of sensor location and directional sensitivity.

PubMed

Hinson, Brian T; Morgansen, Kristi A

2015-10-06

The wings of the hawkmoth Manduca sexta are lined with mechanoreceptors called campaniform sensilla that encode wing deformations. During flight, the wings deform in response to a variety of stimuli, including inertial-elastic loads due to the wing flapping motion, aerodynamic loads, and exogenous inertial loads transmitted by disturbances. Because the wings are actuated, flexible structures, the strain-sensitive campaniform sensilla are capable of detecting inertial rotations and accelerations, allowing the wings to serve not only as a primary actuator, but also as a gyroscopic sensor for flight control. We study the gyroscopic sensing of the hawkmoth wings from a control theoretic perspective. Through the development of a low-order model of flexible wing flapping dynamics, and the use of nonlinear observability analysis, we show that the rotational acceleration inherent in wing flapping enables the wings to serve as gyroscopic sensors. We compute a measure of sensor fitness as a function of sensor location and directional sensitivity by using the simulation-based empirical observability Gramian. Our results indicate that gyroscopic information is encoded primarily through shear strain due to wing twisting, where inertial rotations cause detectable changes in pronation and supination timing and magnitude. We solve an observability-based optimal sensor placement problem to find the optimal configuration of strain sensor locations and directional sensitivities for detecting inertial rotations. The optimal sensor configuration shows parallels to the campaniform sensilla found on hawkmoth wings, with clusters of sensors near the wing root and wing tip. The optimal spatial distribution of strain directional sensitivity provides a hypothesis for how heterogeneity of campaniform sensilla may be distributed.

Correlation of hemocyte counts with different developmental parameters during the last larval instar of the tobacco hornworm, Manduca sexta.

PubMed

Beetz, Susann; Holthusen, Traute K; Koolman, Jan; Trenczek, Tina

2008-02-01

We determined the changes in hemocyte titer and in the abundance of hemocyte types of the tobacco hornworm Manduca sexta during the fourth and fifth larval stadium and the beginning of the pupal stadium. As we analyzed the samples of individual insects at daily intervals, we were able to correlate phenotypical features, body weight, as well as total protein content and lysozyme activity in the hemolymph with the observations on hemocytes. In the course of the fifth larval stadium, the hemocyte titer decreased slightly and declined further after pupation. Using calculated values for total hemocyte numbers, females had about five times and males three times more hemocytes in the circulating population at the beginning of the wandering stage (in the middle of the fifth larval stadium) than immediately after the last larval--larval molt (from the fourth to the fifth larval stadium). This sexual difference was mainly due to an increase in the number of plasmatocytes, which was more prominent in females than in males. Granular cells were dominant in early fifth larval stadium while plasmatocytes were the most abundant cells in pupae. Oenocytoids and spherule cells disappeared during the wandering stage. Lysozyme activity in the hemolymph rose to a maximum during the wandering stage, with females having lysozyme values twice as high as those for males. These changes in lysozyme activity, however, did not correlate with the increase of total hemolymph protein titer which occurred already at the beginning of the wandering stage. We postulate that changes in hemocyte titers are under direct hormonal control, which has to be proven in future experiments. (c) 2007 Wiley-Liss, Inc.

Ecdysteroids affect in vivo protein metabolism of the flight muscle of the tobacco hornworm (Manduca sexta)

NASA Technical Reports Server (NTRS)

Tischler, M. E.; Wu, M.; Cook, P.; Hodsden, S.

1990-01-01

Ecdysteroid growth promotion of the dorsolongitudinal flight muscle of Manduca sexta was studied by measuring in vivo protein metabolism using both "flooding-dose" and "non-carrier" techniques. These procedures differ in that the former method includes injection of non-labelled phenylalanine (30 micromoles/insect) together with the [3H]amino acid. Injected radioactivity plateaued in the haemolymph within 7 min. With the flooding-dose method, haemolymph and intramuscular specific radioactivities were similar between 15 min and 2 h. Incorporation of [3H]phenylalanine into muscle protein was linear with either method between 30 and 120 min. Fractional rates (%/12 h) of synthesis with the flooding-dose technique were best measured after 1 h because of the initial delay in radioactivity equilibration. Estimation of body phenylalanine turnover with the non-carrier method showed 24-53%/h which was negligible with the flooding-dose method. Since the two methods yielded similar rates of protein synthesis, the large injection of non-labelled amino acid did not alter the rate of synthesis. Because the flooding-dose technique requires only a single time point measurement, it is the preferred method. The decline and eventual cessation of flight-muscle growth was mostly a consequence of declining protein synthesis though degradation increased between 76-86 h before eclosion and was relatively rapid. This decline in muscle growth could be prevented by treating pupae with 20-hydroxyecdysone (10 micrograms/insect). Protein accretion was promoted by a decline of up to 80% in protein breakdown, which was offset in part by a concurrent though much smaller decrease in protein synthesis. Therefore, ecdysteroids may increase flight-muscle growth by inhibiting proteolysis.

Pyruvate cycling and implications for regulation of gluconeogenesis in the insect, Manduca sexta L.

PubMed

Thompson, S N

2000-08-11

Pyruvate cycling was examined in the insect Manduca sexta L. (2-(13)C)pyruvate was injected into 5th instar larvae maintained on a semisynthetic high sucrose, low sucrose, or sucrose-free diet. Pyruvate cycling and gluconeogenesis were determined from the distribution of (13)C in blood metabolites, including trehalose, the blood sugar of insects, and alanine. Pyruvate cycling was evident from the (13)C enrichment of alanine C3, synthesized by transamination of pyruvate following carboxylation to oxaloacetate and cycling through phosphoenolpyruvate. Based on the relative (13)C enrichments of alanine C2 and C3, insects maintained on the high sucrose diet displayed higher levels of cycling than insects on the other diets. Insects on all the diets, when subsequently starved, displayed low levels of cycling. Gluconeogenesis was evident in insects on sucrose-free or low sucrose diets from the selective (13)C enrichment in trehalose. The level of gluconeogenesis relative to glycolysis was indicated by the (13)C enrichment of trehalose C6 and alanine C3, both enrichments metabolically derived in the same manner. Insects starved after maintenance on the sucrose-free or low sucrose diets remained glucogenic. Insects on the high sucrose diet were not glucogenic, and subsequent starvation did not induce gluconeogenesis. The results indicate that pyruvate kinase plays a critical role in regulating the gluconeogenic/glycolytic balance, and that inhibition of pyruvate kinase is a principal regulatory event during induction of de novo trehalose synthesis. Gluconeogenesis failed to maintain homeostatic levels of blood trehalose, supporting the conclusion that blood sugar level may be important for mediating nutrient intake. Possible factors involved in the regulation of gluconeogenesis in insects are discussed. Copyright 2000 Academic Press.

A cardioactive peptide from the southern armyworm, Spodoptera eridania.

PubMed

Furuya, K; Hackett, M; Cirelli, M A; Schegg, K M; Wang, H; Shabanowitz, J; Hunt, D F; Schooley, D A

1999-01-01

A cardioactive peptide was isolated from extracts of whole heads of the southern armyworm, Spodoptera eridania. This peptide has the sequence ENFAVGCTPGYQRTADGRCKPTF (Mr = 2516.8), determined from both Edman sequencing and tandem mass spectrometry in combination with off-line micropreparative capillary liquid chromatography. This peptide, termed Spoer-CAP23, has excitatory effects on a semi-isolated heart from larval Manduca sexta, causing an inotropic effect at low concentrations of peptide and chronotropic and inotropic effects at high doses. The threshold concentration for stimulatory effects of the synthetic peptide on the semi-isolated heart was about 1 nM, suggesting a physiological role as a neuropeptide.

Cytokinin levels and signaling respond to wounding and the perception of herbivore elicitors in Nicotiana attenuata

PubMed Central

Schäfer, Martin; Meza-Canales, Ivan D; Navarro-Quezada, Aura; Brütting, Christoph; Vanková, Radomira; Baldwin, Ian T; Meldau, Stefan

2015-01-01

Nearly half a century ago insect herbivores were found to induce the formation of green islands by manipulating cytokinin (CK) levels. However, the response of the CK pathway to attack by chewing insect herbivores remains unclear. Here, we characterize the CK pathway of Nicotiana attenuata (Torr. ex S. Wats.) and its response to wounding and perception of herbivore-associated molecular patterns (HAMPs). We identified 44 genes involved in CK biosynthesis, inactivation, degradation, and signaling. Leaf wounding rapidly induced transcriptional changes in multiple genes throughout the pathway, as well as in the levels of CKs, including isopentenyladenosine and cis-zeatin riboside; perception of HAMPs present in the oral secretions (OS) of the specialist herbivore Manduca sexta amplified these responses. The jasmonate pathway, which triggers many herbivore-induced processes, was not required for these HAMP-triggered changes, but rather suppressed the CK responses. Interestingly CK pathway changes were observed also in systemic leaves in response to wounding and OS application indicating a role of CKs in mediating long distance systemic processes in response to herbivory. Since wounding and grasshopper OS elicited similar accumulations of CKs in Arabidopsis thaliana L., we propose that CKs are integral components of wounding and HAMP-triggered responses in many plant species. PMID:24924599

Tissue Specific Diurnal Rhythms of Metabolites and Their Regulation during Herbivore Attack in a Native Tobacco, Nicotiana attenuata

PubMed Central

Kim, Sang-Gyu; Gulati, Jyotasana; Baldwin, Ian T.

2011-01-01

Ecological performance is all about timing and the endogenous clock that allows the entrainment of rhythms and anticipation of fitness-determining events is being rapidly characterized. How plants anticipate daily abiotic stresses, such as cold in early mornings and drought at noon, as well as biotic stresses, such as the timing of pathogen infections, is being explored, but little is known about the clock's role in regulating responses to insect herbivores and mutualists, whose behaviors are known to be strongly diurnally regulated and whose attack is known to reconfigure plant metabolomes. We developed a liquid chromatography-mass spectrometry procedure and analyzed its output with model-based peak picking algorithms to identify metabolites with diurnal accumulation patterns in sink/source leaves and roots in an unbiased manner. The response of metabolites with strong diurnal patterns to simulated attack from the specialist herbivore, Manduca sexta larvae was analyzed and annotated with in-house and public databases. Roots and leaves had largely different rhythms and only 10 ions of 182 oscillating ions in leaves and 179 oscillating ions in roots were rhythmic in both tissues: root metabolites mainly peaked at dusk or night, while leaf metabolites peaked during the day. Many oscillating metabolites showed tissue-specific regulation by simulated herbivory of which systemic responses in unattacked tissues were particularly pronounced. Diurnal and herbivory-elicited accumulation patterns of disaccharide, phenylalanine, tyrosine, lyciumoside I, coumaroyl tyramine, 12-oxophytodienoic acid and jasmonic acid and those of their related biosynthetic transcripts were examined in detail. We conclude that oscillating metabolites of N. attenuata accumulate in a highly tissue-specific manner and the patterns reveal pronounced diurnal rhythms in the generalized and specialized metabolism that mediates the plant's responses to herbivores and mutualists. We propose that diurnal regulation will prove to an important element in orchestrating a plant's responses to herbivore attack. PMID:22028833

Polyamines Attenuate Ethylene-Mediated Defense Responses to Abrogate Resistance to Botrytis cinerea in Tomato1[C][W][OA

PubMed Central

Nambeesan, Savithri; AbuQamar, Synan; Laluk, Kristin; Mattoo, Autar K.; Mickelbart, Michael V.; Ferruzzi, Mario G.; Mengiste, Tesfaye; Handa, Avtar K.

2012-01-01

Transgenic tomato (Solanum lycopersicum) lines overexpressing yeast spermidine synthase (ySpdSyn), an enzyme involved in polyamine (PA) biosynthesis, were developed. These transgenic lines accumulate higher levels of spermidine (Spd) than the wild-type plants and were examined for responses to the fungal necrotrophs Botrytis cinerea and Alternaria solani, bacterial pathogen Pseudomonas syringae pv tomato DC3000, and larvae of the chewing insect tobacco hornworm (Manduca sexta). The Spd-accumulating transgenic tomato lines were more susceptible to B. cinerea than the wild-type plants; however, responses to A. solani, P. syringae, or M. sexta were similar to the wild-type plants. Exogenous application of ethylene precursors, S-adenosyl-Met and 1-aminocyclopropane-1-carboxylic acid, or PA biosynthesis inhibitors reversed the response of the transgenic plants to B. cinerea. The increased susceptibility of the ySpdSyn transgenic tomato to B. cinerea was associated with down-regulation of gene transcripts involved in ethylene biosynthesis and signaling. These data suggest that PA-mediated susceptibility to B. cinerea is linked to interference with the functions of ethylene in plant defense. PMID:22128140

A serine proteinase homologue, SPH-3, plays a central role in insect immunity.

PubMed

Felföldi, Gabriella; Eleftherianos, Ioannis; Ffrench-Constant, Richard H; Venekei, István

2011-04-15

Numerous vertebrate and invertebrate genes encode serine proteinase homologues (SPHs) similar to members of the serine proteinase family, but lacking one or more residues of the catalytic triad. These SPH proteins are thought to play a role in immunity, but their precise functions are poorly understood. In this study, we show that SPH-3 (an insect non-clip domain-containing SPH) is of central importance in the immune response of a model lepidopteran, Manduca sexta. We examine M. sexta infection with a virulent, insect-specific, Gram-negative bacterium Photorhabdus luminescens. RNA interference suppression of bacteria-induced SPH-3 synthesis severely compromises the insect's ability to defend itself against infection by preventing the transcription of multiple antimicrobial effector genes, but, surprisingly, not the transcription of immune recognition genes. Upregulation of the gene encoding prophenoloxidase and the activity of the phenoloxidase enzyme are among the antimicrobial responses that are severely attenuated on SPH-3 knockdown. These findings suggest the existence of two largely independent signaling pathways controlling immune recognition by the fat body, one governing effector gene transcription, and the other regulating genes encoding pattern recognition proteins.

Chitin synthase genes in Manduca sexta: characterization of a gut-specific transcript and differential tissue expression of alternately spliced mRNAs during development.

PubMed

Hogenkamp, David G; Arakane, Yasuyuki; Zimoch, Lars; Merzendorfer, Hans; Kramer, Karl J; Beeman, Richard W; Kanost, Michael R; Specht, Charles A; Muthukrishnan, Subbaratnam

2005-06-01

Chitin, the linear homopolymer of beta-1,4-linked N-acetylglucosamine, is produced by the enzyme chitin synthase (CHS). In general, this insoluble polysaccharide is found in two major extracellular structures in insects, the cuticle that overlays the epidermis and the peritrophic membrane (PM) that lines the midgut. Based on amino acid sequence similarities, insect CHSs are divided into two classes, A and B, and to date no more than two CHS genes have been identified in any single insect species. In species where both CHSs have been identified, one class A CHS and one class B CHS are always present. This finding suggests that these two genes may encode enzymes that synthesize chitin in different epithelial tissues. In our laboratory, we previously characterized transcripts for a class A CHS gene (MsCHS1) from the tobacco hornworm, Manduca sexta. We observed the expression of this gene in the larval epidermis, suggesting that the encoded enzyme functions to synthesize cuticular chitin. In this paper, we characterize a second chitin synthase gene (MsCHS2) belonging to class B and its cDNA from Manduca and show that it is expressed only in the midgut. This cDNA contains an open reading frame of 4575 nucleotides, which encodes a conceptual protein that is 1524 amino acids in length and is predicted to contain 16 transmembrane spans. Northern blot analysis of RNA isolated from anterior, medial, and posterior sections of the midgut from feeding larvae indicate that MsCHS2 is primarily expressed in the anterior midgut, with transcript levels tapering off in the medial and posterior midgut. Analysis of the MsCHS2 gene sequence indicates the absence of an alternate exon in contrast to the MsCHS1 gene, which yields two transcripts, MsCHS1a and MsCHS1b. RT-PCR analysis of the differential expression of these alternately spliced transcripts reveals that both splice variants are present in the epidermis. However, the ratio of the two alternately spliced transcripts varies during development, with MsCHS1a being generally more predominant. Southern blot analysis using a probe specific for CHS indicated that Manduca has only two CHS genes, akin to other insect species. Results from an analysis of expression of both genes in different tissues and developmental times indicate that the MsCHS1 enzyme is used for the synthesis of chitin in the cuticle and tracheae, whereas MsCHS2 is utilized exclusively for the synthesis of PM-associated chitin in the midgut.

Interactions of dietary protein and carbohydrate determine blood sugar level and regulate nutrient selection in the insect Manduca sexta L.

PubMed

Thompson, S N; Redak, R A

2000-09-01

The non-homeostatic regulation of blood sugar concentration in the insect Manduca sexta L. was affected by nutritional status. Larvae maintained on diets lacking sucrose displayed low concentrations of trehalose, the blood sugar of insects, which varied from 5 to 15 mM with increasing dietary casein level between 12.5 and 75 g/l. These insects were glucogenic, as demonstrated by the selective 13C enrichment of trehalose synthesized from [3-13C]alanine, and de novo synthesis was the sole source of blood sugar. The distribution of 13C in glutamine established that following transamination of the 13C substituted substrate, [3-13C]pyruvate carboxylation rather than decarboxylation was the principal pathway of Pyr metabolism. The mean blood trehalose level was higher in insects maintained on diets with sucrose. At the lowest dietary casein level blood trehalose was approximately 50 mM, and declined to 20 mM at the highest casein level. Gluconeogenesis was detected in insects maintained on sucrose-free diets at the higher protein levels examined, but [3-13C]pyruvate decarboxylation and TCA cycle metabolism was the principal fate of [3-13C]alanine following transamination, and dietary carbohydrate was the principal source of glucose for trehalose synthesis. Feeding studies established a relationship between nutritional status, blood sugar level and dietary self-selection. Insects preconditioned by feeding on diets without sucrose had low blood sugar levels regardless of dietary casein level, and when subsequently given a choice between a sucrose diet or a casein diet, selected the former. Larvae preconditioned on a diet containing sucrose and the lowest level of casein had high blood sugar levels and subsequently selected the casein diet. Larvae maintained on the sucrose diet with the highest casein level had low blood sugar and self-selected the sucrose diet. When preconditioned on diets with sucrose and intermediate levels of casein, insects selected more equally between the sucrose and the casein diets. It is concluded that blood sugar level may be intimately involved in dietary self-selection by M. sexta larvae, and that in the absence of dietary carbohydrate, gluconeogenesis provides sufficient blood sugar to ensure that larvae choose a diet or diets that produce an optimal intake of dietary protein and carbohydrate.

Silencing brassinosteroid receptor BRI1 impairs herbivory-elicited accumulation of jasmonic acid-isoleucine and diterpene glycosides, but not jasmonic acid and trypsin proteinase inhibitors in Nicotiana attenuata.

PubMed

Yang, Da-Hai; Baldwin, Ian T; Wu, Jianqiang

2013-06-01

The brassinosteroid (BR) receptor, BR insensitive 1 (BRI1), plays a critical role in plant development, but whether BRI1-mediated BR signaling is involved in plant defense responses to herbivores was largely unknown. Here, we examined the function of BRI1 in the resistance of Nicotiana attenuata (Solanaceae) to its specialist insect herbivore Manduca sexta. Jasmonic acid (JA) and JA-isoleucine conjugate (JA-Ile) are important hormones that mediate resistance to herbivores and we found that after wounding or simulated herbivory NaBRI1 had little effect on JA levels, but was important for the induction of JA-Ile. Further experiments revealed that decreased JAR (the enzyme for JA-Ile production) activity and availability of Ile in NaBRI1-silenced plants were likely responsible for the low JA-Ile levels. Consistently, M. sexta larvae gained more weight on NaBRI1-silenced plants than on the control plants. Quantification of insect feeding-induced secondary metabolites revealed that silencing NaBRI1 resulted in decreased levels of carbon-rich defensive secondary metabolites (hydroxygeranyllinalool diterpene glycosides, chlorogenic acid, and rutin), but had little effect on the nitrogen-rich ones (nicotine and trypsin proteinase inhibitors). Thus, NaBRI1-mediated BR signaling is likely involved in plant defense responses to M. sexta, including maintaining JA-Ile levels and the accumulation of several carbon-rich defensive secondary metabolites. © 2013 Institute of Botany, Chinese Academy of Sciences.

A Floral Fragrance, Methyl Benzoate, is An Efficient Green Pesticide

NASA Astrophysics Data System (ADS)

Feng, Yan; Zhang, Aijun

2017-02-01

Over-reliance on synthetic pesticides in insect pest control has caused widespread public and scientific concerns for human health and the environment, especially since many insect pests have already developed resistances to conventional pesticides and Bt products. For this reason, there is a considerable interest in development of alternative control methods for insect pest management. Based on laboratory studies, we report that methyl benzoate (MB), a naturally-occurring compound in many plants, may possess toxicity against various stages of a variety of insect pests, including the brown marmorated stinkbug, Halyomorpha halys, diamondback moth, Plutella xylostella, and tobacco hornworm, Manduca sexta, as well as the spotted wing drosophila, Drosophila suzukii. Based on our laboratory toxicity data, MB was at least 5 to 20 times more toxic than the conventional pyrethroid (β-cyfluthrin), sulfur & pyrethrin mixture, and some organic commercial products available on the market against H. halys, P. xylostella, and M. sexta, eggs. Because MB is considered an environment-friendly, it has great potential to be used as an alternative tool to synthetic pesticide for insect pest management in crop production, thereby, reducing threats to natural ecosystems and human health caused by over-application of conventional synthetic pesticides.

Direct effects of hypoxia and nitric oxide on ecdysone secretion by insect prothoracic glands.

PubMed

DeLalio, Leon J; Dion, Sara M; Bootes, Abigail M; Smith, Wendy A

2015-05-01

Insect molting and metamorphosis are controlled by the molt stimulating hormone ecdysone. A recent study suggests that reduced tissue oxygenation correlates with the size-sensing mechanism responsible for triggering molting. When reared in hypoxia, larvae of Manduca sexta and Drosophila melanogaster initiate molting at lower weights than do larvae reared in normoxia. Furthermore, in Drosophila, the signaling gas nitric oxide (NO) appears to be required for normal developmental timing. As observed in Drosophila, NO signaling targets the nuclear hormone receptor beta fushi tarazu transcription factor 1 (βFTZ-F1) through activation of Drosophila hormone receptor 3 (DHR3), two key regulators of ecdysone production and metamorphic tissue progression. We set out to directly examine the effects of hypoxia and NO on ecdysone secretion using prothoracic glands from feeding fifth (last) larval stage M. sexta. Our results indicate that in vitro treatment of prothoracic glands with hypoxia (2% oxygen) or the NO donor DETA-NONOate significantly inhibit ecdysone secretion. Protein markers of glandular activity were also in keeping with an initial inhibition, measured a decrease in phosphorylated ERK (extracellular signal regulated kinase) and an increase in non-phosphorylated 4EBP (eukaryotic initiation factor 4E binding protein). Additionally, gene expression levels of Manduca hormone receptor 3 (mhr3), βftz-f1, nitric oxide synthase (nos), and the PTTH receptor torso, were quantified using real-time PCR. NO treatment increased mhr3 expression and decreased nos expression. Hypoxia increased mhr3 transcription after 2 hr, but decreased transcription after 12 hr, with no effect on nos expression. Both NO and hypoxia had small effects on βftz-f1 expression, yet strongly increased torso transcription. Our results demonstrate that, in isolated prothoracic glands, hypoxia and NO signaling directly inhibit ecdysteroid secretion, but at the same time alter aspects of prothoracic gland function that may enhance secretory response. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of within-instar development on tracheal diameter and hypoxia-inducible factors α and β in the tobacco hornworm, Manduca sexta.

PubMed

Lundquist, Taylor A; Kittilson, Jeffrey D; Ahsan, Rubina; Greenlee, Kendra J

2017-12-12

As insects grow within an instar, body mass increases, often more than doubling. The increase in mass causes an increase in metabolic rate and hence oxygen demand. However, the insect tracheal system is hypothesized to increase only after molting and may be compressed as tissues grow within an instar. The increase in oxygen demand in the face of a potentially fixed or decreasing supply could result in hypoxia as insects near the end of an instar. To test these hypotheses, we first used synchrotron X-ray imaging to determine how diameters of large tracheae change within an instar and after molting to the next instar in the tobacco hornworm, Manduca sexta. Large tracheae did not increase in diameter within the first, second, third, and fourth instars, but increased upon molting. To determine if insects are hypoxic at the end of instars, we used the presence of hypoxia-inducible factors (HIFs) as an index. HIF-α and HIF-β dimerize in hypoxia and act as a transcription factor that turns on genes that will increase oxygen delivery. We sequenced both of these genes and measured their mRNA levels at the beginning and end of each larval instar. Finally, we obtained an antibody to HIF-α and measured protein expression during the same time. Both mRNA and protein levels of HIFs were increased at the end of most instars. These data support the hypothesis that some insects may experience hypoxia at the end of an instar, which could be a signal for molting. As caterpillars grow within an instar, major tracheae do not increase in size, while metabolic demand increases. At the same life stages, caterpillars increased expression of hypoxia inducible factors, suggesting that they become hypoxic near the end of an instar. Copyright © 2017 Elsevier Ltd. All rights reserved.

Flower-specific jasmonate signaling regulates constitutive floral defenses in wild tobacco

PubMed Central

Li, Ran; Wang, Ming; Wang, Yang; Schuman, Meredith C.; Weinhold, Arne; Schäfer, Martin; Jiménez-Alemán, Guillermo H.; Barthel, Andrea; Baldwin, Ian T.

2017-01-01

Optimal defense (OD) theory predicts that within a plant, tissues are defended in proportion to their fitness value and risk of predation. The fitness value of leaves varies greatly and leaves are protected by jasmonate (JA)-inducible defenses. Flowers are vehicles of Darwinian fitness in flowering plants and are attacked by herbivores and pathogens, but how they are defended is rarely investigated. We used Nicotiana attenuata, an ecological model plant with well-characterized herbivore interactions to characterize defense responses in flowers. Early floral stages constitutively accumulate greater amounts of two well-characterized defensive compounds, the volatile (E)-α-bergamotene and trypsin proteinase inhibitors (TPIs), which are also found in herbivore-induced leaves. Plants rendered deficient in JA biosynthesis or perception by RNA interference had significantly attenuated floral accumulations of defensive compounds known to be regulated by JA in leaves. By RNA-seq, we found a JAZ gene, NaJAZi, specifically expressed in early-stage floral tissues. Gene silencing revealed that NaJAZi functions as a flower-specific jasmonate repressor that regulates JAs, (E)-α-bergamotene, TPIs, and a defensin. Flowers silenced in NaJAZi are more resistant to tobacco budworm attack, a florivore. When the defensin was ectopically expressed in leaves, performance of Manduca sexta larvae, a folivore, decreased. NaJAZi physically interacts with a newly identified NINJA-like protein, but not the canonical NINJA. This NINJA-like recruits the corepressor TOPLESS that contributes to the suppressive function of NaJAZi on floral defenses. This study uncovers the defensive function of JA signaling in flowers, which includes components that tailor JA signaling to provide flower-specific defense. PMID:28784761

Contribution of different taste cells and signaling pathways to the discrimination of "bitter" taste stimuli by an insect.

PubMed

Glendinning, John I; Davis, Adrienne; Ramaswamy, Sudha

2002-08-15

Animals can discriminate among many different types of foods. This discrimination process involves multiple sensory systems, but the sense of taste is known to play a central role. We asked how the taste system contributes to the discrimination of different "bitter" taste stimuli in Manduca sexta caterpillars. This insect has approximately eight bilateral pairs of taste cells that respond selectively to bitter taste stimuli. Each bilateral pair of bitter-sensitive taste cells has a different molecular receptive range (MRR); some of these taste cells also contain two signaling pathways with distinctive MRRs and temporal patterns of spiking. To test for discrimination, we habituated the caterpillar's taste-mediated aversive response to one bitter taste stimulus (salicin) and then asked whether this habituation phenomenon generalized to four other bitter taste stimuli (caffeine, aristolochic acid, Grindelia extract, and Canna extract). We inferred that the two compounds were discriminable if the habituation phenomenon failed to generalize (e.g., from salicin to aristolochic acid). We found that M. sexta could discriminate between salicin and those bitter taste stimuli that activate (1) different populations of bitter-sensitive taste cells (Grindelia extract and Canna extract) or (2) different signaling pathways within the same bitter-sensitive taste cell (aristolochic acid). M. sexta could not discriminate between salicin and a bitter taste stimulus that activates the same signaling pathway within the same bitter-sensitive taste cell (caffeine). We propose that the heterogeneous population of bitter-sensitive taste cells and signaling pathways within this insect facilitates the discrimination of bitter taste stimuli.

A new twist on gyroscopic sensing: body rotations lead to torsion in flapping, flexing insect wings.

PubMed

Eberle, A L; Dickerson, B H; Reinhall, P G; Daniel, T L

2015-03-06

Insects perform fast rotational manoeuvres during flight. While two insect orders use flapping halteres (specialized organs evolved from wings) to detect body dynamics, it is unknown how other insects detect rotational motions. Like halteres, insect wings experience gyroscopic forces when they are flapped and rotated and recent evidence suggests that wings might indeed mediate reflexes to body rotations. But, can gyroscopic forces be detected using only changes in the structural dynamics of a flapping, flexing insect wing? We built computational and robotic models to rotate a flapping wing about an axis orthogonal to flapping. We recorded high-speed video of the model wing, which had a flexural stiffness similar to the wing of the Manduca sexta hawkmoth, while flapping it at the wingbeat frequency of Manduca (25 Hz). We compared the three-dimensional structural dynamics of the wing with and without a 3 Hz, 10° rotation about the yaw axis. Our computational model revealed that body rotation induces a new dynamic mode: torsion. We verified our result by measuring wing tip displacement, shear strain and normal strain of the robotic wing. The strains we observed could stimulate an insect's mechanoreceptors and trigger reflexive responses to body rotations. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

A new twist on gyroscopic sensing: body rotations lead to torsion in flapping, flexing insect wings

PubMed Central

Eberle, A. L.; Dickerson, B. H.; Reinhall, P. G.; Daniel, T. L.

2015-01-01

Insects perform fast rotational manoeuvres during flight. While two insect orders use flapping halteres (specialized organs evolved from wings) to detect body dynamics, it is unknown how other insects detect rotational motions. Like halteres, insect wings experience gyroscopic forces when they are flapped and rotated and recent evidence suggests that wings might indeed mediate reflexes to body rotations. But, can gyroscopic forces be detected using only changes in the structural dynamics of a flapping, flexing insect wing? We built computational and robotic models to rotate a flapping wing about an axis orthogonal to flapping. We recorded high-speed video of the model wing, which had a flexural stiffness similar to the wing of the Manduca sexta hawkmoth, while flapping it at the wingbeat frequency of Manduca (25 Hz). We compared the three-dimensional structural dynamics of the wing with and without a 3 Hz, 10° rotation about the yaw axis. Our computational model revealed that body rotation induces a new dynamic mode: torsion. We verified our result by measuring wing tip displacement, shear strain and normal strain of the robotic wing. The strains we observed could stimulate an insect's mechanoreceptors and trigger reflexive responses to body rotations. PMID:25631565

Higher-order neural processing tunes motion neurons to visual ecology in three species of hawkmoths.

PubMed

Stöckl, A L; O'Carroll, D; Warrant, E J

2017-06-28

To sample information optimally, sensory systems must adapt to the ecological demands of each animal species. These adaptations can occur peripherally, in the anatomical structures of sensory organs and their receptors; and centrally, as higher-order neural processing in the brain. While a rich body of investigations has focused on peripheral adaptations, our understanding is sparse when it comes to central mechanisms. We quantified how peripheral adaptations in the eyes, and central adaptations in the wide-field motion vision system, set the trade-off between resolution and sensitivity in three species of hawkmoths active at very different light levels: nocturnal Deilephila elpenor, crepuscular Manduca sexta , and diurnal Macroglossum stellatarum. Using optical measurements and physiological recordings from the photoreceptors and wide-field motion neurons in the lobula complex, we demonstrate that all three species use spatial and temporal summation to improve visual performance in dim light. The diurnal Macroglossum relies least on summation, but can only see at brighter intensities. Manduca, with large sensitive eyes, relies less on neural summation than the smaller eyed Deilephila , but both species attain similar visual performance at nocturnal light levels. Our results reveal how the visual systems of these three hawkmoth species are intimately matched to their visual ecologies. © 2017 The Author(s).

Flight duration and flight muscle ultrastructure of unfed hawk moths.

PubMed

Wone, Bernard W M; Pathak, Jaika; Davidowitz, Goggy

2018-06-13

Flight muscle breakdown has been reported for many orders of insects, but the basis of this breakdown in insects with lifelong dependence on flight is less clear. Lepidopterans show such muscle changes across their lifespans, yet how this change affects the ability of these insects to complete their life cycles is not well documented. We investigated the changes in muscle function and ultrastructure of unfed aging adult hawk moths (Manduca sexta). Flight duration was examined in young, middle-aged, and advanced-aged unfed moths. After measurement of flight duration, the main flight muscle (dorsolongitudinal muscle) was collected and histologically prepared for transmission electron microscopy to compare several measurements of muscle ultrastructure among moths of different ages. Muscle function assays revealed significant positive correlations between muscle ultrastructure and flight distance that were greatest in middle-aged moths and least in young moths. In addition, changes in flight muscle ultrastructure were detected across treatment groups. The number of mitochondria in muscle cells peaked in middle-aged moths. Many wild M. sexta do not feed as adults; thus, understanding the changes in flight capacity and muscle ultrastructure in unfed moths provides a more complete understanding of the ecophysiology and resource allocation strategies of this species. Copyright © 2018 Elsevier Ltd. All rights reserved.

Control of moth flight posture is mediated by wing mechanosensory feedback.

PubMed

Dickerson, Bradley H; Aldworth, Zane N; Daniel, Thomas L

2014-07-01

Flying insects rapidly stabilize after perturbations using both visual and mechanosensory inputs for active control. Insect halteres are mechanosensory organs that encode inertial forces to aid rapid course correction during flight but serve no aerodynamic role and are specific to two orders of insects (Diptera and Strepsiptera). Aside from the literature on halteres and recent work on the antennae of the hawkmoth Manduca sexta, it is unclear how other flying insects use mechanosensory information to control body dynamics. The mechanosensory structures found on the halteres, campaniform sensilla, are also present on wings, suggesting that the wings can encode information about flight dynamics. We show that the neurons innervating these sensilla on the forewings of M. sexta exhibit spike-timing precision comparable to that seen in previous reports of campaniform sensilla, including haltere neurons. In addition, by attaching magnets to the wings of moths and subjecting these animals to a simulated pitch stimulus via a rotating magnetic field during tethered flight, we elicited the same vertical abdominal flexion reflex these animals exhibit in response to visual or inertial pitch stimuli. Our results indicate that, in addition to their role as actuators during locomotion, insect wings serve as sensors that initiate reflexes that control body dynamics. © 2014. Published by The Company of Biologists Ltd.

Parasitoid-host endocrine relations: self-reliance or co-optation?

PubMed

Cole, T J; Beckage, N E; Tan, F F; Srinivasan, A; Ramaswamy, S B

2002-12-01

High titers of juvenile hormone (JH) maintain developmental arrest in Manduca sexta larvae parasitized by Cotesia congregata. Parasitized hosts exhibit up to 9.5 times greater amounts of total hemolymph JH (from 0.6+/-0.09 to 2.51+/-0.43ng/ml) compared to non-parasitized controls. Elevated titers are observed throughout the fifth instar, even beyond egression of the parasitoids on day 5. GC-MS analysis revealed that in hemolymph of unparasitized control larvae, JH I is the major homolog and levels of JH III are negligible; in parasitized individuals the amounts of JH I, II, and III rise, and JH III predominates. Neck ligation ensured separation of M. sexta's corpora allata from the posterior section, which contained most of the parasitoids in the infected insects. When the posterior region was sampled, JHs were not detected in the non-parasitzed larvae, but in those parasitized, JH III was found (1.98+/-0.29ng/ml, 24 h post-ligation). JH III was the only homolog produced and secreted by the parasitoid in in vitro culture. This is the first report stating that a parasitoid secretes JH III and may contribute, at least in part, to the circulating titer in the host hemocoel, concurrently promoting host production of JH I and II.

Pest-managing efficacy of trans-asarone isolated from Daucus carota L. seeds.

PubMed

Momin, Rafikali A; Nair, Muraleeddharan G

2002-07-31

The bioactive hexane extract of Daucus carota seed yielded 2,4,5-trimethoxybenzaldehyde (1), oleic acid (2), trans-asarone (3), and geraniol (4). Compounds 1-4 were evaluated for their mosquitocidal, nematicidal, antifeedant, and antimicrobial activities. Only trans-asarone was active in the assays performed, causing 100% mortality to fourth-instar mosquito larvae, Aedes aegyptii, at 200 microg mL(-1) and the nematodes Caenorhabditis elegans and Panagrellus redivivus at 100 microg mL(-1). In feeding trials, trans-asarone also caused significant weight reductions of the caterpillars Helicovarpa zea, Heliothis virescens, and Manduca sexta when incorporated into artificial diet at a concentration of 100 microg mL(-1). Also, it exhibited slight activity at 100 microg mL(-1) against the yeasts Candida albicans, Candida parapsilasis, and Candida kruseii.

Remote sensing of future competitors: Impacts on plant defenses

PubMed Central

Izaguirre, Miriam M.; Mazza, Carlos A.; Biondini, Mariela; Baldwin, Ian T.; Ballaré, Carlos L.

2006-01-01

Far-red radiation (FR) reflected by green tissues is a key signal that plants use to detect the proximity of future competitors. Perception of increased levels of FR elicits a suite of responses collectively known as the shade-avoidance syndrome, which includes increased stem elongation, production of erect leaves, and reduced lateral branching. These responses improve the access to light for plants that occur in crowded populations. Responses to the proximity of competitors are known to affect the susceptibility to disease and predation in several organisms, including social animals. However, the impacts of warning signals of competition on the expression of defenses have not been explicitly investigated in plants. In the experiments reported here, we show that reflected FR induced a dramatic down-regulation of chemical defenses in wild tobacco (Nicotiana longiflora). FR altered the expression of several defense-related genes, inhibited the accumulation of herbivore-induced phenolic compounds, and augmented the performance of the specialist herbivore Manduca sexta. Complementary studies with tomato suggested that the effects of FR on defenses are mediated by the photoreceptor phytochrome B. The central implication of these results is that shade-intolerant species such as wild tobacco and tomato activate functional changes that affect their ability to cope with herbivore attack in response to phytochrome signals of future competition, even in the absence of real competition for resources. These findings suggest that competition overshadowed herbivory during the evolution of this group of species and add a new axis to the definition of the shade-avoidance syndrome. PMID:16632610

Flexible strategies for flight control: an active role for the abdomen.

PubMed

Dyhr, Jonathan P; Morgansen, Kristi A; Daniel, Thomas L; Cowan, Noah J

2013-05-01

Moving animals orchestrate myriad motor systems in response to multimodal sensory inputs. Coordinating movement is particularly challenging in flight control, where animals deal with potential instability and multiple degrees of freedom of movement. Prior studies have focused on wings as the primary flight control structures, for which changes in angle of attack or shape are used to modulate lift and drag forces. However, other actuators that may impact flight performance are reflexively activated during flight. We investigated the visual-abdominal reflex displayed by the hawkmoth Manduca sexta to determine its role in flight control. We measured the open-loop stimulus-response characteristics (measured as a transfer function) between the visual stimulus and abdominal response in tethered moths. The transfer function reveals a 41 ms delay and a high-pass filter behavior with a pass band starting at ~0.5 Hz. We also developed a simplified mathematical model of hovering flight wherein articulation of the thoracic-abdominal joint redirects an average lift force provided by the wings. We show that control of the joint, subject to a high-pass filter, is sufficient to maintain stable hovering, but with a slim stability margin. Our experiments and models suggest a novel mechanism by which articulation of the body or 'airframe' of an animal can be used to redirect lift forces for effective flight control. Furthermore, the small stability margin may increase flight agility by easing the transition from stable flight to a more maneuverable, unstable regime.

Role of β-Oxidation in Jasmonate Biosynthesis and Systemic Wound Signaling in TomatoW⃞

PubMed Central

Li, Chuanyou; Schilmiller, Anthony L.; Liu, Guanghui; Lee, Gyu In; Jayanty, Sastry; Sageman, Carolyn; Vrebalov, Julia; Giovannoni, James J.; Yagi, Kaori; Kobayashi, Yuichi; Howe, Gregg A.

2005-01-01

Jasmonic acid (JA) is a lipid-derived signal that regulates plant defense responses to biotic stress. Here, we report the characterization of a JA-deficient mutant of tomato (Lycopersicon esculentum) that lacks local and systemic expression of defensive proteinase inhibitors (PIs) in response to wounding. Map-based cloning studies demonstrated that this phenotype results from loss of function of an acyl-CoA oxidase (ACX1A) that catalyzes the first step in the peroxisomal β-oxidation stage of JA biosynthesis. Recombinant ACX1A exhibited a preference for C12 and C14 straight-chain acyl-CoAs and also was active in the metabolism of C18 cyclopentanoid-CoA precursors of JA. The overall growth, development, and reproduction of acx1 plants were similar to wild-type plants. However, the mutant was compromised in its defense against tobacco hornworm (Manduca sexta) attack. Grafting experiments showed that loss of ACX1A function disrupts the production of the transmissible signal for wound-induced PI expression but does not affect the recognition of this signal in undamaged responding leaves. We conclude that ACX1A is essential for the β-oxidation stage of JA biosynthesis and that JA or its derivatives is required both for antiherbivore resistance and the production of the systemic wound signal. These findings support a role for peroxisomes in the production of lipid-based signaling molecules that promote systemic defense responses. PMID:15722469

Development and steroid regulation of RFamide immunoreactivity in antennal-lobe neurons of the sphinx moth Manduca sexta.

PubMed

Schachtner, Joachim; Trosowski, Björn; D'Hanis, Wolfgang; Stubner, Stephan; Homberg, Uwe

2004-06-01

During metamorphosis, the insect nervous system undergoes considerable remodeling: new neurons are integrated while larval neurons are remodeled or eliminated. To understand further the mechanisms involved in transforming larval to adult tissue we have mapped the metamorphic changes in a particularly well established brain area, the antennal lobe of the sphinx moth Manduca sexta, using an antiserum recognizing RFamide-related neuropeptides. Five types of RFamide-immunoreactive (ir) neurons could be distinguished in the antennal lobe, based on morphology and developmental appearance. Four cell types (types II-V, each consisting of one or two cells) showed RFamide immunostaining in the larva that persisted into metamorphosis. By contrast, the most prominent group (type I), a mixed population of local and projection neurons consisting of about 60 neurons in the adult antennal lobe, acquired immunostaining in a two-step process during metamorphosis. In a first step, from 5 to 7 days after pupal ecdysis, the number of labeled neurons reached about 25. In a second step, starting about 4 days later, the number of RFamide-ir neurons increased within 6 days to about 60. This two-step process parallels the rise and fall of the developmental hormone 20-hydroxyecdysone (20E) in the hemolymph. Artificially shifting the 20E peak to an earlier developmental time point resulted in the precocious appearance of RFamide immunostaining and led to premature formation of glomeruli. Prolonging high 20E concentrations to stages when the hormone titer starts to decline had no effect on the second increase of immunostained cell numbers. These results support the idea that the rise in 20E, which occurs after pupal ecdysis, plays a role in the first phase of RFamide expression and in glomeruli formation in the developing antennal lobes. The role of 20E in the second phase of RFamide expression is less clear, but increased cell numbers showing RFamide-ir do not appear to be a consequence of the declining levels in 20E that occur during adult development.

Insect cyborgs: a new frontier in flight control systems

NASA Astrophysics Data System (ADS)

Reissman, Timothy; Crawford, Jackie H.; Garcia, Ephrahim

2007-04-01

The development of a micro-UAV via a cybernetic organism, primarily the Manduca sexta moth, is presented. An observer to gather output data of the system response of the moth is given by means of an image following system. The visual tracking was implemented to gather the required information about the time history of the moth's six degrees of freedom. This was performed with three cameras tracking a white line as a marker on the moth's thorax to maximize contrast between the moth and the marker. Evaluation of the implemented six degree of freedom visual tracking system finds precision greater than 0.1 mm within three standard deviations and accuracy on the order of 1 mm. Acoustic and visual response systems are presented to lay the groundwork for creating a stochastic response catalog of the organisms to varied stimuli.

Natural history-driven, plant-mediated RNAi-based study reveals CYP6B46's role in a nicotine-mediated antipredator herbivore defense.

PubMed

Kumar, Pavan; Pandit, Sagar S; Steppuhn, Anke; Baldwin, Ian T

2014-01-28

Manduca sexta (Ms) larvae are known to efficiently excrete ingested nicotine when feeding on their nicotine-producing native hostplant, Nicotiana attenuata. Here we describe how ingested nicotine is co-opted for larval defense by a unique mechanism. Plant-mediated RNAi was used to silence a midgut-expressed, nicotine-induced cytochrome P450 6B46 (CYP6B46) in larvae consuming transgenic N. attenuata plants producing MsCYP6B46 dsRNA. These and transgenic nicotine-deficient plants were planted into native habitats to study the phenotypes of larvae feeding on these plants and the behavior of their predators. The attack-behavior of a native wolf spider (Camptocosa parallela), a major nocturnal predator, provided the key to understanding MsCYP6B46's function: spiders clearly preferred CYP6B46-silenced larvae, just as they had preferred larvae fed nicotine-deficient plants. MsCYP6B46 redirects a small amount (0.65%) of ingested nicotine from the midgut into hemolymph, from which nicotine is exhaled through the spiracles as an antispider signal. CYP6B46-silenced larvae were more susceptible to spider-attack because they exhaled less nicotine because of lower hemolymph nicotine concentrations. CYP6B46-silenced larvae were impaired in distributing ingested nicotine from midgut to hemolymph, but not in the clearing of hemolymph nicotine or in the exhalation of nicotine from hemolymph. MsCYP6B46 could be a component of a previously hypothesized pump that converts nicotine to a short-lived, transportable, metabolite. Other predators, big-eyed bugs, and antlion larvae were insensitive to this defense. Thus, chemical defenses, too toxic to sequester, can be repurposed for defensive functions through respiration as a form of defensive halitosis, and predators can assist the functional elucidation of herbivore genes.

Insect Development in Altered Gravitational Environment

NASA Technical Reports Server (NTRS)

Tischler, Marc E.

1996-01-01

When tobacco hornworm (Manduca sexta) larvae burrow underground (25-30 cm) to pupate, they reorient themselves to a relatively horizontal position indicating an ability to sense gravity. To evaluate their sensitivity to gravitational environment during metamorphosis, Manduca (pharate adults) were placed in a vertical (head-up) position. Distinct morphological changes, each one reflecting ensuing phases, were used to follow adult development. Five days after pupation, the vertical group showed accelerated (P less than 0.05) development and were nearly 4 phases ahead (P less than 0.0001) after 10 days. Differences in development in the vertical group were characterized further by increased (7-48%) hemolymph concentrations of 13 amino acids, but a decrease in cys and pro and no change in arg, his, met and val (trp, undetectable). Decreased (36%) turnover of injected H-3 - phenylalanine suggested slower utilization of amino acids contributed, at least partly, to the increased concentrations. Vertically-oriented Manduca also exhibited a greater (20 %, P less than 0.001) protein content in their flight muscles near the end of development. Analysis of hemolymph sugar levels showed a redistribution of sugars from the monosaccharide glucose to the disaccharide trehalose. Since injection of 20-hydroxyecdysone decreased (49%) turnover of H-3- phenylalanine in pharate adults and since ecdysteroids are known to increase flight muscle size and control adult development, these results are consistent with our measuring a greater (+80%, P less than 0.05) ecdysteroid titer in the vertically-oriented insects. These results suggest that gravity environment influences ecdysone output by the pharate adult. When we evaluated hemolymph flow in the head-up and control positions, we found that injected C-14-inulin was distributed somewhat more rapidly in the head-up group irrespective of the sight of injection (head or abdomen) likely because in the head-up position flow of the hemolymph is facilitated throughout the animal. Other experiments showed that an intact prothoracic gland is needed for the response. Hence vertical, head-up orientation affects release of ecdysone from the prothoracic gland.

Discovery and quantitative structure-activity relationship study of lepidopteran HMG-CoA reductase inhibitors as selective insecticides.

PubMed

Zang, Yang-Yang; Li, Yuan-Mei; Yin, Yue; Chen, Shan-Shan; Kai, Zhen-Peng

2017-09-01

In a previous study we have demonstrated that insect 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) can be a potential selective insecticide target. Three series of inhibitors were designed on the basis of the difference in HMGR structures from Homo sapiens and Manduca sexta, with the aim of discovering potent selective insecticide candidates. An in vitro bioassay showed that gem-difluoromethylenated statin analogues have potent effects on JH biosynthesis of M. sexta and high selectivity between H. sapiens and M. sexta. All series II compounds {1,3,5-trisubstituted [4-tert-butyl 2-(5,5-difluoro-2,2-dimethyl-6-vinyl-4-yl) acetate] pyrazoles} have some effect on JH biosynthesis, whereas most of them are inactive on human HMGR. In particular, the IC 50 value of compound II-12 (37.8 nm) is lower than that of lovastatin (99.5 nm) and similar to that of rosuvastatin (24.2 nm). An in vivo bioassay showed that I-1, I-2, I-3 and II-12 are potential selective insecticides, especially for lepidopteran pest control. A predictable and statistically meaningful CoMFA model of 23 inhibitors (20 as training sets and three as test sets) was obtained with a value of q 2 and r 2 of 0.66 and 0.996 respectively. The final model suggested that a potent insect HMGR inhibitor should contain suitable small and non-electronegative groups in the ring part, and electronegative groups in the side chain. Four analogues were discovered as potent selective lepidopteran HMGR inhibitors, which can specifically be used for lepidopteran pest control. The CoMFA model will be useful for the design of new selective insect HMGR inhibitors that are structurally related to the training set compounds. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Plant volatile eliciting FACs in lepidopteran caterpillars, fruit flies, and crickets: a convergent evolution or phylogenetic inheritance?

PubMed Central

Yoshinaga, Naoko; Abe, Hiroaki; Morita, Sayo; Yoshida, Tetsuya; Aboshi, Takako; Fukui, Masao; Tumlinson, James H.; Mori, Naoki

2013-01-01

Fatty acid amino acid conjugates (FACs), first identified in lepidopteran caterpillar spit as elicitors of plant volatile emission, also have been reported as major components in gut tracts of Drosophila melanogaster and cricket Teleogryllus taiwanemma. The profile of FAC analogs in these two insects was similar to that of tobacco hornworm Manduca sexta, showing glutamic acid conjugates predominantly over glutamine conjugates. The physiological function of FACs is presumably to enhance nitrogen assimilation in Spodoptera litura larvae, but in other insects it is totally unknown. Whether these insects share a common synthetic mechanism of FACs is also unclear. In this study, the biosynthesis of FACs was examined in vitro in five lepidopteran species (M. sexta, Cephonodes hylas, silkworm, S. litura, and Mythimna separata), fruit fly larvae and T. taiwanemma. The fresh midgut tissues of all of the tested insects showed the ability to synthesize glutamine conjugates in vitro when incubated with glutamine and sodium linolenate. Such direct conjugation was also observed for glutamic acid conjugates in all the insects but the product amount was very small and did not reflect the in vivo FAC patterns in each species. In fruit fly larvae, the predominance of glutamic acid conjugates could be explained by a shortage of substrate glutamine in midgut tissues, and in M. sexta, a rapid hydrolysis of glutamine conjugates has been reported. In crickets, we found an additional unique biosynthetic pathway for glutamic acid conjugates. T. taiwanemma converted glutamine conjugates to glutamic acid conjugates by deaminating the side chain of the glutamine moiety. Considering these findings together with previous results, a possibility that FACs in these insects are results of convergent evolution cannot be ruled out, but it is more likely that the ancestral insects had the glutamine conjugates and crickets and other insects developed glutamic acid conjugates in a different way. PMID:24744735

A Lepidopteran-Specific Gene Family Encoding Valine-Rich Midgut Proteins

PubMed Central

Odman-Naresh, Jothini; Duevel, Margret; Muthukrishnan, Subbaratnam; Merzendorfer, Hans

2013-01-01

Many lepidopteran larvae are serious agricultural pests due to their feeding activity. Digestion of the plant diet occurs mainly in the midgut and is facilitated by the peritrophic matrix (PM), an extracellular sac-like structure, which lines the midgut epithelium and creates different digestive compartments. The PM is attracting increasing attention to control lepidopteran pests by interfering with this vital function. To identify novel PM components and thus potential targets for insecticides, we performed an immunoscreening with anti-PM antibodies using an expression library representing the larval midgut transcriptome of the tobacco hornworm, Manduca sexta. We identified three cDNAs encoding valine-rich midgut proteins of M. sexta (MsVmps), which appear to be loosely associated with the PM. They are members of a lepidopteran-specific family of nine VMP genes, which are exclusively expressed in larval stages in M. sexta. Most of the MsVMP transcripts are detected in the posterior midgut, with the highest levels observed for MsVMP1. To obtain further insight into Vmp function, we expressed MsVMP1 in insect cells and purified the recombinant protein. Lectin staining and glycosidase treatment indicated that MsVmp1 is highly O-glycosylated. In line with results from qPCR, immunoblots revealed that MsVmp1 amounts are highest in feeding larvae, while MsVmp1 is undetectable in starving and molting larvae. Finally using immunocytochemistry, we demonstrated that MsVmp1 localizes to the cytosol of columnar cells, which secrete MsVmp1 into the ectoperitrophic space in feeding larvae. In starving and molting larvae, MsVmp1 is found in the gut lumen, suggesting that the PM has increased its permeability. The present study demonstrates that lepidopteran species including many agricultural pests have evolved a set of unique proteins that are not found in any other taxon and thus may reflect an important adaptation in the highly specialized lepidopteran digestive tract facing particular immune challenges. PMID:24312395

Effect of Altered Gravity Environment on Tobacco Hornworm (Manduca Sexta) Development

NASA Technical Reports Server (NTRS)

Tischler, Marc E.

1996-01-01

Metamorphosis provides a unique condition for studying the role of gravity in development. Formation of new organs in a previously existing organism requires a highly active period of turnover of amino acids and proteins, and of changes in the endocrine profile. Furthermore, metamorphosis offers the advantage of studying a self-contained biological system. The tobacco hornworm provides a suitable species to study the effect of altered gravitational environment on invertebrate development. This species has been one of the most thoroughly investigated organisms in a variety of aspects of insect biology. M. sexta pharate adults can provide significant amounts of material with which to work, thus facilitating the study of metabolic aspects of adult development. During wandering, the period immediately following cessation of larval feeding, the larva burrows into the soil to form a pupation chamber. Despite burrowing down 25 to 30 cm, the insects reorient themselves to a slightly head-up (10 +/- 1 degree) position. Since light and temperature are not factors in this process, the larvae must sense the gravity vector. In our ground-based studies we had assessed whether developing adults might be sensitive to their gravitational environment by orienting pupae in a vertical head-up position within 24 to 48 h after pupal ecdysis. Our ground-based findings formed the foundation for determining which parameters would be evaluated in developing Manduca following spaceflight. Measurements were to include: (1) extent of development by all of the insects, (2) analysis of hemolymph obtained from half of the insects postflight for ecdysteroid, amino acid, urea, ammonia and trehalose concentrations, (3) further development of the other half of the insects to adult (moths), (4) analysis of the flight muscle protein content of the adults. Based on the first flight attempt in July, 1995, we modified the BRIC hardware to accommodate the insects. Our studies after BRIC-04 showed that sealing the top and bottom lids of the canisters with an 0-ring and with vacuum grease caused the insects to stop developing because of accumulation of carbon dioxide. Even though removing both the O-rings and vacuum grease permitted normal development, there was still some increase in carbon dioxide levels. Consequently, the canisters were vented and the vents covered with gas permeable membrane.

Dietary fat mediates hyperglycemia and the glucogenic response to increased protein consumption in an insect, Manduca sexta L.

PubMed

Thompson, S N

2004-08-04

Many insects display non-homeostatic regulation over blood sugar level. The concentration of trehalose varies dramatically depending on physiological and nutritional state. In the absence of dietary carbohydrate, blood trehalose in larvae of the lepidopteran insect Manduca sexta is maintained by gluconeogenesis and is dependent on dietary protein consumption. In the present study, the effect of dietary fat on the glucogenic response of insects to increased dietary protein was examined by NMR analysis of (2-13C)pyruvate metabolism. Last instar larvae were maintained on a carbohydrate-free chemically defined artificial diet having variable levels of casein with and without corn oil. Gluconeogenic flux, the ratio of the rate of gluconeogenesis to the rate of glycolysis, was estimated from the 13C distribution in trehalose arising by gluconeogenesis and the 13C enrichment of alanine due to pyruvate cycling. Insects grew well on carbohydrate-free diets and growth increased with increasing dietary protein level. At all dietary protein levels, larvae grew better on diets with fat. Without dietary fat, larvae were glucogenic but displayed low blood trehalose concentrations, <30 mM, regardless of protein consumption. When fat was included in the diet, however, gluconeogenic flux and blood trehalose level increased sharply in response to increased dietary protein level, with trehalose concentrations >50 mM at higher levels of protein consumption. When offered a choice of a high carbohydrate and a high protein diet, larvae maintained on diets with fat displayed a food preference related to blood sugar level. Those with low blood sugar fed on carbohydrate, while those with high blood sugar preferred protein. Trehalose synthesized from (2-13C)pyruvate exhibited asymmetry in the 13C distribution in individual glucose molecules, indicating a disequilibrium at the triose phosphate isomerase-catalyzed step of the gluconeogenic pathway. In trehalose from larvae on diets with fat, the asymmetric 13C distribution was higher than in trehalose from insects on diets lacking fat. This may partially result from isotopic disequilibrium when unenriched glycerol is metabolized to dihydroxyacetone phosphate following fat hydrolysis. The asymmetry in 13C distribution, however, also occurred in insects on diets without fat and decreased with increased gluconeogenic flux suggesting that true disequilibrium between the triose phosphates is the principal reason for the asymmetry.

Visual stimuli induced by self-motion and object-motion modify odour-guided flight of male moths (Manduca sexta L.).

PubMed

Verspui, Remko; Gray, John R

2009-10-01

Animals rely on multimodal sensory integration for proper orientation within their environment. For example, odour-guided behaviours often require appropriate integration of concurrent visual cues. To gain a further understanding of mechanisms underlying sensory integration in odour-guided behaviour, our study examined the effects of visual stimuli induced by self-motion and object-motion on odour-guided flight in male M. sexta. By placing stationary objects (pillars) on either side of a female pheromone plume, moths produced self-induced visual motion during odour-guided flight. These flights showed a reduction in both ground and flight speeds and inter-turn interval when compared with flight tracks without stationary objects. Presentation of an approaching 20 cm disc, to simulate object-motion, resulted in interrupted odour-guided flight and changes in flight direction away from the pheromone source. Modifications of odour-guided flight behaviour in the presence of stationary objects suggest that visual information, in conjunction with olfactory cues, can be used to control the rate of counter-turning. We suggest that the behavioural responses to visual stimuli induced by object-motion indicate the presence of a neural circuit that relays visual information to initiate escape responses. These behavioural responses also suggest the presence of a sensory conflict requiring a trade-off between olfactory and visually driven behaviours. The mechanisms underlying olfactory and visual integration are discussed in the context of these behavioural responses.

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

Binding specificity of the juvenile hormone carrier protein from the hemolymph of the tobacco hornworm Manduca sexta Johannson (Lepidoptera: Sphingidae).

PubMed

Peterson, R C; Reich, M F; Dunn, P E; Law, J H; Katzenellnbogen, J A

1977-05-17

A series of analogues of insect juvenile hormone (four geometric isomers of methyl epoxyfarnesenate, several para-substituted epoxygeranyl phenyl ethers, and epoxyfarnesol and its acetate and haloacetate derivatives) was prepared to investigate the binding specificity of the hemolymph juvenile hormone binding protein from the tobacco hornworm Manduct sexta. The relative binding affinities were determined by a competition assay against radiolabeled methyl (E,E)-3,11-dimethyl-7-ethyl-cis-10,11-epoxytrideca-2,6-dienoate (JH I). The ratio of dissociation constants was estimated by plotting competitor data according to a linear transformation of the dissociation equations describing competition of two ligands for a binding protein. The importance of the geometry of the sesquiterpene hydrocarbon chain is indicated by the fact that the binding affinity is decreased as Z (cis) double bonds are substituted for E (trans) double bonds in the methyl epoxyfarnesenate series; the unepoxidized analogues do not bind. A carboxylic ester function is important although its orientation can be reversed, as indicated by the good binding of epoxyfarnesyl acetate. In the monoterpene series, methyl epoxygeranoate shows no affinity for the binding protein, but substitution of a phenyl or p-carbomethoxyphenyl ether for the ester function imparts a low, but significant affinity. These data taken together with earlier results indicate that the binding site for juvenile hormone in the hemolymph binding protein is characterized by a sterically defined hydrophobic region with polar sites that recognize the epoxide and the ester functions.

Aerodynamic performance and particle image velocimetery of piezo actuated biomimetic manduca sexta engineered wings towards the design and application of a flapping wing flight vehicle

NASA Astrophysics Data System (ADS)

DeLuca, Anthony M.

Considerable research and investigation has been conducted on the aerodynamic performance, and the predominate flow physics of the Manduca Sexta size of biomimetically designed and fabricated wings as part of the AFIT FWMAV design project. Despite a burgeoning interest and research into the diverse field of flapping wing flight and biomimicry, the aerodynamics of flapping wing flight remains a nebulous field of science with considerable variance into the theoretical abstractions surrounding aerodynamic mechanisms responsible for aerial performance. Traditional FWMAV flight models assume a form of a quasi-steady approximation of wing aerodynamics based on an infinite wing blade element model (BEM). An accurate estimation of the lift, drag, and side force coefficients is a critical component of autonomous stability and control models. This research focused on two separate experimental avenues into the aerodynamics of AFIT's engineered hawkmoth wings|forces and flow visualization. 1. Six degree of freedom force balance testing, and high speed video analysis was conducted on 30°, 45°, and 60° angle stop wings. A novel, non-intrusive optical tracking algorithm was developed utilizing a combination of a Gaussian Mixture Model (GMM) and ComputerVision (OpenCV) tools to track the wing in motion from multiple cameras. A complete mapping of the wing's kinematic angles as a function of driving amplitude was performed. The stroke angle, elevation angle, and angle of attack were tabulated for all three wings at driving amplitudes ranging from A=0.3 to A=0.6. The wing kinematics together with the force balance data was used to develop several aerodynamic force coefficient models. A combined translational and rotational aerodynamic model predicted lift forces within 10%, and vertical forces within 6%. The total power consumption was calculated for each of the three wings, and a Figure of Merit was calculated for each wing as a general expression of the overall efficiency of the wing. Th 60° angle stop wing achieved the largest total stroke angle and generated the most lift for the lowest power consumption of the wings tested. 2. Phase averaged stereo Particle Image Velocimetry (PIV) data was collected at eight phases through the flap cycle on the 30°, 45°, and 60° angle stop wings. Wings were mounted transverse and parallel to the interrogating laser sheet, and planar velocity intersections at the wing mid-span, one chord below the wing, were compared to one another to verify data fidelity. A Rankine-Froude actuator disk model was adapted to calculate the approximate vertical thrust generated from the total momentum flux through the flapping semi-disk using the velocity field measurements. Three component stereo u, v, and w-velocity contour measurements confirmed the presence of extensive vortical structures in the vicinity of the wing. The leading edge vortex was successfully tracked through the stroke cycle appearing at approximately 25% span, increasing in circulatory strength and translational velocity down the span toward the tip, and dissipating just after 75% span. Thrust calculations showed the vertically mounted wing more accurately represented the vertical forces when compared to its corresponding force balance measurement than the horizontally mounted wing. The mid-span showed the highest vertical velocity profile below the wing; and hence, was the location responsible for the majority of lift production along the span.

The subtilisin-like protease SBT3 contributes to insect resistance in tomato

PubMed Central

Meyer, Michael; Huttenlocher, Franziska; Cedzich, Anna; Procopio, Susanne; Stroeder, Jasper; Pau-Roblot, Corinne; Lequart-Pillon, Michelle; Pelloux, Jérôme; Stintzi, Annick; Schaller, Andreas

2016-01-01

Subtilisin-like proteases (SBTs) constitute a large family of extracellular plant proteases, the function of which is still largely unknown. In tomato plants, the expression of SBT3 was found to be induced in response to wounding and insect attack in injured leaves but not in healthy systemic tissues. The time course of SBT3 induction resembled that of proteinase inhibitor II and other late wound response genes suggesting a role for SBT3 in herbivore defense. Consistent with such a role, larvae of the specialist herbivore Manduca sexta performed better on transgenic plants silenced for SBT3 expression (SBT3-SI). Supporting a contribution of SBT3 to systemic wound signaling, systemic induction of late wound response genes was attenuated in SBT3-SI plants. The partial loss of insect resistance may thus be explained by a reduction in systemic defense gene expression. Alternatively, SBT3 may play a post-ingestive role in plant defense. Similar to other anti-nutritive proteins, SBT3 was found to be stable and active in the insect’s digestive system, where it may act on unidentified proteins of insect or plant origin. Finally, a reduction in the level of pectin methylesterification that was observed in transgenic plants with altered levels of SBT3 expression suggested an involvement of SBT3 in the regulation of pectin methylesterases (PMEs). While such a role has been described in other systems, PME activity and the degree of pectin methylesterification did not correlate with the level of insect resistance in SBT3-SI and SBT3 overexpressing plants and are thus unrelated to the observed resistance phenotype. PMID:27259555

The Homogeneity of Optimal Sensor Placement Across Multiple Winged Insect Species

NASA Astrophysics Data System (ADS)

Jenkins, Abigail L.

Taking inspiration from biology, control algorithms can be implemented to imitate the naturally occurring control systems present in nature. This research is primarily concerned with insect flight and optimal wing sensor placement. Many winged insects with halteres are equipped with mechanoreceptors termed campaniform sensilla. Although the exact information these receptors provide to the insect's nervous system is unknown, it is thought to have the capability of measuring inertial rotation forces. During flight, when the wing bends, the information measured by the campaniform sensilla is received by the central nervous system, and provides the insect necessary data to control flight. This research compares three insect species - the hawkmoth Manduca sexta, the honeybee Apis mellifera, and the fruit fly Drosophila melanogaster. Using an observability-based sensor placement algorithm, the optimal sensor placement for these three species is determined. Simulations resolve if this optimal sensor placement corresponds to the insect's campaniform sensilla, as well as if placement is homogeneous across species.

Motion visualization and estimation for flapping wing systems

NASA Astrophysics Data System (ADS)

Hsu, Tzu-Sheng Shane; Fitzgerald, Timothy; Nguyen, Vincent Phuc; Patel, Trisha; Balachandran, Balakumar

2017-04-01

Studies of fluid-structure interactions associated with flexible structures such as flapping wings require the capture and quantification of large motions of bodies that may be opaque. As a case study, motion capture of a free flying Manduca sexta, also known as hawkmoth, is considered by using three synchronized high-speed cameras. A solid finite element (FE) representation is used as a reference body and successive snapshots in time of the displacement fields are reconstructed via an optimization procedure. One of the original aspects of this work is the formulation of an objective function and the use of shadow matching and strain-energy regularization. With this objective function, the authors penalize the projection differences between silhouettes of the captured images and the FE representation of the deformed body. The process and procedures undertaken to go from high-speed videography to motion estimation are discussed, and snapshots of representative results are presented. Finally, the captured free-flight motion is also characterized and quantified.

Context dependency of in-flight responses by Manduca sexta moths to ambient differences in relative humidity.

PubMed

Wolfin, Michael S; Raguso, Robert A; Davidowitz, Goggy; Goyret, Joaquin

2018-06-12

The use of sensory information to control behavior usually involves the integration of sensory input from different modalities. This integration is affected by behavioral states and experience, and it is also sensitive to the spatiotemporal patterns of stimulation and other general contextual cues. Following the finding that hawkmoths can use relative humidity (RH) as a proxy for nectar content during close-range foraging, we evaluate here whether RH could be used during locomotive flight under two simulated contexts in a wind tunnel: (1) dispersion and (2) search phase of the foraging behavior. Flying moths showed a bias towards air with a higher RH in a context devoid of foraging stimuli, but the addition of visual and olfactory floral stimuli elicited foraging responses that overrode the behavioral effects of RH. We discuss the results in relation to the putative adaptive value of the context-dependent use of sensory information. © 2018. Published by The Company of Biologists Ltd.

Hawkmoths evaluate scenting flowers with the tip of their proboscis

PubMed Central

Haverkamp, Alexander; Yon, Felipe; Keesey, Ian W; Mißbach, Christine; Koenig, Christopher; Hansson, Bill S; Baldwin, Ian T

2016-01-01

Pollination by insects is essential to many ecosystems. Previously, we have shown that floral scent is important to mediate pollen transfer between plants (Kessler et al., 2015). Yet, the mechanisms by which pollinators evaluate volatiles of single flowers remained unclear. Here, Nicotiana attenuata plants, in which floral volatiles have been genetically silenced and its hawkmoth pollinator, Manduca sexta, were used in semi-natural tent and wind-tunnel assays to explore the function of floral scent. We found that floral scent functions to increase the fitness of individual flowers not only by increasing detectability but also by enhancing the pollinator's foraging efforts. Combining proboscis choice tests with neurophysiological, anatomical and molecular analyses we show that this effect is governed by newly discovered olfactory neurons on the tip of the moth's proboscis. With the tip of their tongue, pollinators assess the advertisement of individual flowers, an ability essential for maintaining this important ecosystem service. DOI: http://dx.doi.org/10.7554/eLife.15039.001 PMID:27146894

A comparative analysis of serpin genes in the silkworm genome

PubMed Central

Zou, Zhen; Picheng, Zhao; Weng, Hua; Mita, Kazuei; Jiang, Haobo

2009-01-01

Serine protease inhibitors (serpins) are a superfamily of proteins, most of which control protease-mediated processes by inhibiting their cognate enzymes. Sequencing of the silkworm genome provides an opportunity to investigate serpin structure, function, and evolution at the genome level. There are thirty-four serpin genes in Bombyx mori. Six are highly similar to their Manduca sexta orthologs that regulate innate immunity. Three alternative exons in serpin1 gene and four in serpin28 encode a variable region including the reactive site loop. Splicing of serpin2 pre-mRNA yields variations in serpin2A, 2A′ and 2B. Sequence similarity and intron positions reveal the evolutionary pathway of seven serpin genes in group C. RT-PCR indicates an increase in the mRNA levels of serpin1, 3, 5, 6, 9, 12, 13, 25, 27, 32 and 34 in fat body and hemocytes of larvae injected with bacteria. These results suggest that the silkworm serpins play regulatory roles in defense responses. PMID:19150649

Metaflumizone is a novel sodium channel blocker insecticide.

PubMed

Salgado, V L; Hayashi, J H

2007-12-15

Metaflumizone is a novel semicarbazone insecticide, derived chemically from the pyrazoline sodium channel blocker insecticides (SCBIs) discovered at Philips-Duphar in the early 1970s, but with greatly improved mammalian safety. This paper describes studies confirming that the insecticidal action of metaflumizone is due to the state-dependent blockage of sodium channels. Larvae of the moth Spodoptera eridania injected with metaflumizone became paralyzed, concomitant with blockage of all nerve activity. Furthermore, tonic firing of abdominal stretch receptor organs from Spodoptera frugiperda was blocked by metaflumizone applied in the bath, consistent with the block of voltage-dependent sodium channels. Studies on native sodium channels, in primary-cultured neurons isolated from the CNS of the larvae of the moth Manduca sexta and on Para/TipE sodium channels heterologously expressed in Xenopus (African clawed frog) oocytes, confirmed that metaflumizone blocks sodium channels by binding selectively to the slow-inactivated state, which is characteristic of the SCBIs. The results confirm that metaflumizone is a novel sodium channel blocker insecticide.

A 4-Dimensional Representation of Antennal Lobe Output Based on an Ensemble of Characterized Projection Neurons

PubMed Central

Staudacher, Erich M.; Huetteroth, Wolf; Schachtner, Joachim; Daly, Kevin C.

2009-01-01

A central problem facing studies of neural encoding in sensory systems is how to accurately quantify the extent of spatial and temporal responses. In this study, we take advantage of the relatively simple and stereotypic neural architecture found in invertebrates. We combine standard electrophysiological techniques, recently developed population analysis techniques, and novel anatomical methods to form an innovative 4-dimensional view of odor output representations in the antennal lobe of the moth Manduca sexta. This novel approach allows quantification of olfactory responses of characterized neurons with spike time resolution. Additionally, arbitrary integration windows can be used for comparisons with other methods such as imaging. By assigning statistical significance to changes in neuronal firing, this method can visualize activity across the entire antennal lobe. The resulting 4-dimensional representation of antennal lobe output complements imaging and multi-unit experiments yet provides a more comprehensive and accurate view of glomerular activation patterns in spike time resolution. PMID:19464513

Pest and disease resistance enhanced by heterologous suppression of a Nicotiana plumbaginifolia cytochrome P450 gene CYP72A2.

PubMed

Smigocki, Ann C; Wilson, Dennis

2004-12-01

The functional role of the Nicotiana plumbaginifolia cytochrome P450 gene CYP72A2 was investigated in transgenic plants. N. tabacum plants transformed with a sense or antisense CYP72A2 construct exhibited diminished heights, branched stems, smaller leaves and deformed flowers. Western blot analysis revealed reduced levels of a 58 kDa protein corresponding to CYP72A2, suggesting that the CYP72A2 homolog was suppressed in the sense and antisense plants. Transgenic plants had increased resistance to Manduca sexta larvae that consumed about 35 to 90 less of transgenic versus control leaves. A virulent strain of Pseudomonas syringae pv. tabaci induced a disease-limiting response followed by a delayed and decreased development of disease symptoms in the transgenics. CYP72A2 gene mediated resistance suggests that the plant-pest or -pathogen interactions may have been modified by changes in bioactive metabolite pools.

YC-1 BINDING TO THE BETA SUBUNIT OF SOLUBLE GUANYLYL CYCLASE OVERCOMES ALLOSTERIC INHIBITION BY THE ALPHA SUBUNIT

PubMed Central

Purohit, Rahul; Fritz, Bradley G.; The, Juliana; Issaian, Aaron; Weichsel, Andrzej; David, Cynthia L.; Campbell, Eric; Hausrath, Andrew C.; Rassouli-Taylor, Leida; Garcin, Elsa D.; Gage, Matthew J.; Montfort, William R.

2014-01-01

Soluble guanylate cyclase (sGC) is a heterodimeric heme protein and the primary nitric oxide receptor. NO binding stimulates cyclase activity, leading to regulation of cardiovascular physiology and making sGC an attractive target for drug discovery. YC-1 and related compounds stimulate sGC both independently and synergistically with NO and CO binding; however, where the compounds bind and how they work remains unknown. Using linked-equilibria binding measurements, surface plasmon resonance, and domain truncations in Manduca sexta and bovine sGC, we demonstrate that YC-1 binds near or directly to the heme-containing domain of the beta subunit. In the absence of CO, YC-1 binds with Kd = 9–21 μM, depending on construct. In the presence of CO, these values decrease to 0.6–1.1 μM. Pfizer compound 25 bound ~10-fold weaker than YC-1 in the absence of CO whereas compound BAY 41–2272 bound particularly tightly in the presence of CO (Kd = 30–90 nM). Additionally, we found that CO binding is much weaker to heterodimeric sGC proteins (Kd = 50–100 μM) than to the isolated heme domain (Kd = 0.2 μM for Manduca beta H-NOX/PAS). YC-1 greatly enhanced CO binding to heterodimeric sGC, as expected (Kd = ~1 μM). These data indicate the alpha subunit induces a heme pocket conformation with lower affinity for CO and NO. YC-1 family compounds bind near the heme domain, overcoming the alpha subunit effect and inducing a heme pocket conformation with high affinity. We propose this high-affinity conformation is required for the full-length protein to achieve high catalytic activity. PMID:24328155

REVERSE SIGNALING BY GPI-LINKED MANDUCA EPHRIN REQUIRES A SRC FAMILY KINASE TO RESTRICT NEURONAL MIGRATION IN VIVO

PubMed Central

Coate, Thomas M.; Swanson, Tracy L.; Copenhaver, Philip F.

2011-01-01

Reverse signaling via GPI-linked Ephrins may help control cell proliferation and outgrowth within the nervous system, but the mechanisms underlying this process remain poorly understood. In the embryonic enteric nervous system (ENS) of the moth Manduca sexta, migratory neurons forming the enteric plexus (EP cells) express a single Ephrin ligand (GPI-linked MsEphrin), while adjacent midline cells that are inhibitory to migration express the cognate receptor (MsEph). Knocking down MsEph receptor expression in cultured embryos with antisense morpholino oligonucleotides allowed the EP cells to cross the midline inappropriately, consistent with the model that reverse signaling via MsEphrin mediates a repulsive response in the ENS. Src family kinases have been implicated in reverse signaling by type-A Ephrins in other contexts, and MsEphrin colocalizes with activated forms of endogenous Src in the leading processes of the EP cells. Pharmacological inhibition of Src within the developing ENS induced aberrant midline crossovers, similar to the effect of blocking MsEphrin reverse signaling. Hyperstimulating MsEphrin reverse signaling with MsEph-Fc fusion proteins induced the rapid activation of endogenous Src specifically within the EP cells, as assayed by Western blots of single embryonic gut explants and by whole-mount immunostaining of cultured embryos. In longer cultures, treatment with MsEph-Fc caused a global inhibition of EP cell migration and outgrowth, an effect that was prevented by inhibiting Src activation. These results support the model that MsEphrin reverse signaling induces the Src-dependent retraction of EP cell processes away from the enteric midline, thereby helping to confine the neurons to their appropriate pathways. PMID:19295147

Pollinator choice in Petunia depends on two major genetic Loci for floral scent production.

PubMed

Klahre, Ulrich; Gurba, Alexandre; Hermann, Katrin; Saxenhofer, Moritz; Bossolini, Eligio; Guerin, Patrick M; Kuhlemeier, Cris

2011-05-10

Differences in floral traits, such as petal color, scent, morphology, or nectar quality and quantity, can lead to specific interactions with pollinators and may thereby cause reproductive isolation. Petunia provides an attractive model system to study the role of floral characters in reproductive isolation and speciation. The night-active hawkmoth pollinator Manduca sexta relies on olfactory cues provided by Petunia axillaris. In contrast, Petunia exserta, which displays a typical hummingbird pollination syndrome, is devoid of scent. The two species can easily be crossed in the laboratory, which makes it possible to study the genetic basis of the evolution of scent production and the importance of scent for pollinator behavior. In an F2 population derived from an interspecific cross between P. axillaris and P. exserta, we identified two quantitative trait loci (QTL) that define the difference between the two species' ability to produce benzenoid volatiles. One of these loci was identified as the MYB transcription factor ODORANT1. Reciprocal introgressions of scent QTL were used for choice experiments under controlled conditions. These experiments demonstrated that the hawkmoth M. sexta prefers scented plants and that scent determines choice at a short distance. When exposed to conflicting cues of color versus scent, the insects display no preference, indicating that color and scent are equivalent cues. Our results show that scent is an important flower trait that defines plant-pollinator interactions at the level of individual plants. The genetic basis underlying such a major phenotypic difference appears to be relatively simple and may enable rapid loss or gain of scent through hybridization. Copyright © 2011 Elsevier Ltd. All rights reserved.

Speciation genes in the genus Petunia

PubMed Central

Venail, Julien; Dell'Olivo, Alexandre; Kuhlemeier, Cris

2010-01-01

A major innovation in angiosperms is the recruitment of animal pollinators as a means to enhance the efficiency and specificity of pollen transfer. The implementation of this reproductive strategy involved the rapid and presumably coordinated evolution of multiple floral traits. A major question concerns the molecular identity of the genetic polymorphisms that specify the phenotypic differences between distinct pollination syndromes. Here, we report on our work with Petunia, an attractive model system for quantitative plant genetics and genomics. From interspecific crosses, we obtained F2 plants that differed in the length of the floral tube or the size of the limb. We used these plants to study the behaviour of the hawkmoth pollinator, Manduca sexta. Plants with larger limbs were preferentially visited, consistent with the notion that flower size affects visibility under low light conditions. The moths also displayed an innate preference for shorter tubes. However, in those cases that flowers with long tubes were chosen, the animals fed for equal time. Thus, the perception of tube length may help the moths, early on, to avoid those plants that are more difficult to handle. PMID:20047872

The neural bases of host plant selection in a Neuroecology framework.

PubMed

Reisenman, Carolina E; Riffell, Jeffrey A

2015-01-01

Understanding how animals make use of environmental information to guide behavior is a fundamental problem in the field of neuroscience. Similarly, the field of ecology seeks to understand the role of behavior in shaping interactions between organisms at various levels of organization, including population-, community- and even ecosystem-level scales. Together, the newly emerged field of "Neuroecology" seeks to unravel this fundamental question by studying both the function of neurons at many levels of the sensory pathway and the interactions between organisms and their natural environment. The interactions between herbivorous insects and their host plants are ideal examples of Neuroecology given the strong ecological and evolutionary forces and the underlying physiological and behavioral mechanisms that shaped these interactions. In this review we focus on an exemplary herbivorous insect within the Lepidoptera, the giant sphinx moth Manduca sexta, as much is known about the natural behaviors related to host plant selection and the involved neurons at several level of the sensory pathway. We also discuss how herbivore-induced plant odorants and secondary metabolites in floral nectar in turn can affect moth behavior, and the underlying neural mechanisms.

Lepidopteran HMG-CoA reductase is a potential selective target for pest control

PubMed Central

Li, Yuan-mei; Huang, Juan; Tobe, Stephen S.

2017-01-01

As a consequence of the negative impacts on the environment of some insecticides, discovery of eco-friendly insecticides and target has received global attention in recent years. Sequence alignment and structural comparison of the rate-limiting enzyme HMG-CoA reductase (HMGR) revealed differences between lepidopteran pests and other organisms, which suggested insect HMGR could be a selective insecticide target candidate. Inhibition of JH biosynthesis in vitro confirmed that HMGR inhibitors showed a potent lethal effect on the lepidopteran pest Manduca sexta, whereas there was little effect on JH biosynthesis in Apis mellifera and Diploptera punctata. The pest control application of these inhibitors demonstrated that they can be insecticide candidates with potent ovicidal activity, larvicidal activity and insect growth regulatory effects. The present study has validated that Lepidopteran HMGR can be a potent selective insecticide target, and the HMGR inhibitors (especially type II statins) could be selective insecticide candidates and lead compounds. Furthermore, we demonstrated that sequence alignment, homology modeling and structural comparison may be useful for determining potential enzymes or receptors which can be eco-friendly pesticide  targets. PMID:28133568

Lepidopteran HMG-CoA reductase is a potential selective target for pest control.

PubMed

Li, Yuan-Mei; Kai, Zhen-Peng; Huang, Juan; Tobe, Stephen S

2017-01-01

As a consequence of the negative impacts on the environment of some insecticides, discovery of eco-friendly insecticides and target has received global attention in recent years. Sequence alignment and structural comparison of the rate-limiting enzyme HMG-CoA reductase (HMGR) revealed differences between lepidopteran pests and other organisms, which suggested insect HMGR could be a selective insecticide target candidate. Inhibition of JH biosynthesis in vitro confirmed that HMGR inhibitors showed a potent lethal effect on the lepidopteran pest Manduca sexta , whereas there was little effect on JH biosynthesis in Apis mellifera and Diploptera punctata . The pest control application of these inhibitors demonstrated that they can be insecticide candidates with potent ovicidal activity, larvicidal activity and insect growth regulatory effects. The present study has validated that Lepidopteran HMGR can be a potent selective insecticide target, and the HMGR inhibitors (especially type II statins) could be selective insecticide candidates and lead compounds. Furthermore, we demonstrated that sequence alignment, homology modeling and structural comparison may be useful for determining potential enzymes or receptors which can be eco-friendly pesticide  targets.

Adipokinetic hormone-induced antioxidant response in Spodoptera littoralis.

PubMed

Večeřa, Josef; Krishnan, Natraj; Mithöfer, Axel; Vogel, Heiko; Kodrík, Dalibor

2012-03-01

The antioxidative potential of the Manduca sexta adipokinetic hormone (Manse-AKH) in the last instar larvae of Spodoptera littoralis (Noctuidae, Lepidoptera) was demonstrated after exposure to oxidative stress (OS) elicited by feeding on artificial diet containing tannic acid (TA). Determination of protein carbonyls (PCs) and reduced glutathione (GSH) levels, monitoring of activity of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione-S-transferases (GSTs), as well as measuring of the mRNA expression of CAT and SOD were used as markers of the OS. Injection of the Manse-AKH (5 pmol per individual) reversed the OS status by mitigation of PCs formation and by stimulation of glutathione-S-transferases (GSTs) activity. The CAT and SOD mRNA expression was significantly suppressed after the Manse-AKH injection while activity of these enzymes was not affected. These results indicate that diminishing of OS after the AKH injection might be a result of activation of specific enzymatic pathway possibly at the post-translational level rather than a direct effect on regulation of antioxidant marker genes at the transcriptional level. Copyright © 2011 Elsevier Inc. All rights reserved.

System identification and sensorimotor determinants of flight maneuvers in an insect

NASA Astrophysics Data System (ADS)

Sponberg, Simon; Hall, Robert; Roth, Eatai

Locomotor maneuvers are inherently closed-loop processes. They are generally characterized by the integration of multiple sensory inputs and adaptation or learning over time. To probe sensorimotor processing we take a system identification approach treating the underlying physiological systems as dynamic processes and altering the feedback topology in experiment and analysis. As a model system, we use agile hawk moths (Manduca sexta), which feed from real and robotic flowers while hovering in mid air. Moths rely on vision and mechanosensation to track floral targets and can do so at exceptionally low luminance levels despite hovering being a mechanically unstable behavior that requires neural feedback to stabilize. By altering the sensory environment and placing mechanical and visual signals in conflict we show a surprisingly simple linear summation of visual and mechanosensation produces a generative prediction of behavior to novel stimuli. Tracking performance is also limited more by the mechanics of flight than the magnitude of the sensory cue. A feedback systems approach to locomotor control results in new insights into how behavior emerges from the interaction of nonlinear physiological systems.

Manduca Contactin Regulates Amyloid Precursor Protein-Dependent Neuronal Migration

PubMed Central

Ramaker, Jenna M.; Swanson, Tracy L.

2016-01-01

Amyloid precursor protein (APP) was originally identified as the source of β-amyloid peptides that accumulate in Alzheimer's disease (AD), but it also has been implicated in the control of multiple aspects of neuronal motility. APP belongs to an evolutionarily conserved family of transmembrane proteins that can interact with a variety of adapter and signaling molecules. Recently, we showed that both APP and its insect ortholog [APPL (APP-Like)] directly bind the heterotrimeric G-protein Goα, supporting the model that APP can function as an unconventional Goα-coupled receptor. We also adapted a well characterized assay of neuronal migration in the hawkmoth, Manduca sexta, to show that APPL–Goα signaling restricts ectopic growth within the developing nervous system, analogous to the role postulated for APP family proteins in controlling migration within the mammalian cortex. Using this assay, we have now identified Manduca Contactin (MsContactin) as an endogenous ligand for APPL, consistent with previous work showing that Contactins interact with APP family proteins in other systems. Using antisense-based knockdown protocols and fusion proteins targeting both proteins, we have shown that MsContactin is selectively expressed by glial cells that ensheath the migratory neurons (expressing APPL), and that MsContactin–APPL interactions normally prevent inappropriate migration and outgrowth. These results provide new evidence that Contactins can function as authentic ligands for APP family proteins that regulate APP-dependent responses in the developing nervous system. They also support the model that misregulated Contactin–APP interactions might provoke aberrant activation of Goα and its effectors, thereby contributing to the neurodegenerative sequelae that typify AD. SIGNIFICANCE STATEMENT Members of the amyloid precursor protein (APP) family participate in many aspects of neuronal development, but the ligands that normally activate APP signaling have remained controversial. This research provides new evidence that members of the Contactin family function as authentic ligands for APP and its orthologs, and that this evolutionarily conserved class of membrane-attached proteins regulates key aspects of APP-dependent migration and outgrowth in the embryonic nervous system. By defining the normal role of Contactin–APP signaling during development, these studies also provide the framework for investigating how the misregulation of Contactin–APP interactions might contribute to neuronal dysfunction in the context of both normal aging and neurodegenerative conditions, including Alzheimer's disease. PMID:27535920

Construction and sequence sampling of deep-coverage, large-insert BAC libraries for three model lepidopteran species

PubMed Central

Wu, Chengcang; Proestou, Dina; Carter, Dorothy; Nicholson, Erica; Santos, Filippe; Zhao, Shaying; Zhang, Hong-Bin; Goldsmith, Marian R

2009-01-01

Background Manduca sexta, Heliothis virescens, and Heliconius erato represent three widely-used insect model species for genomic and fundamental studies in Lepidoptera. Large-insert BAC libraries of these insects are critical resources for many molecular studies, including physical mapping and genome sequencing, but not available to date. Results We report the construction and characterization of six large-insert BAC libraries for the three species and sampling sequence analysis of the genomes. The six BAC libraries were constructed with two restriction enzymes, two libraries for each species, and each has an average clone insert size ranging from 152–175 kb. We estimated that the genome coverage of each library ranged from 6–9 ×, with the two combined libraries of each species being equivalent to 13.0–16.3 × haploid genomes. The genome coverage, quality and utility of the libraries were further confirmed by library screening using 6~8 putative single-copy probes. To provide a first glimpse into these genomes, we sequenced and analyzed the BAC ends of ~200 clones randomly selected from the libraries of each species. The data revealed that the genomes are AT-rich, contain relatively small fractions of repeat elements with a majority belonging to the category of low complexity repeats, and are more abundant in retro-elements than DNA transposons. Among the species, the H. erato genome is somewhat more abundant in repeat elements and simple repeats than those of M. sexta and H. virescens. The BLAST analysis of the BAC end sequences suggested that the evolution of the three genomes is widely varied, with the genome of H. virescens being the most conserved as a typical lepidopteran, whereas both genomes of H. erato and M. sexta appear to have evolved significantly, resulting in a higher level of species- or evolutionary lineage-specific sequences. Conclusion The high-quality and large-insert BAC libraries of the insects, together with the identified BACs containing genes of interest, provide valuable information, resources and tools for comprehensive understanding and studies of the insect genomes and for addressing many fundamental questions in Lepidoptera. The sample of the genomic sequences provides the first insight into the constitution and evolution of the insect genomes. PMID:19558662

The Lepidoptera Odorant Binding Protein gene family: Gene gain and loss within the GOBP/PBP complex of moths and butterflies.

PubMed

Vogt, Richard G; Große-Wilde, Ewald; Zhou, Jing-Jiang

2015-07-01

Butterflies and moths differ significantly in their daily activities: butterflies are diurnal while moths are largely nocturnal or crepuscular. This life history difference is presumably reflected in their sensory biology, and especially the balance between the use of chemical versus visual signals. Odorant Binding Proteins (OBP) are a class of insect proteins, at least some of which are thought to orchestrate the transfer of odor molecules within an olfactory sensillum (olfactory organ), between the air and odor receptor proteins (ORs) on the olfactory neurons. A Lepidoptera specific subclass of OBPs are the GOBPs and PBPs; these were the first OBPs studied and have well documented associations with olfactory sensilla. We have used the available genomes of two moths, Manduca sexta and Bombyx mori, and two butterflies, Danaus plexippus and Heliconius melpomene, to characterize the GOBP/PBP genes, attempting to identify gene orthologs and document specific gene gain and loss. First, we identified the full repertoire of OBPs in the M. sexta genome, and compared these with the full repertoire of OBPs from the other three lepidopteran genomes, the OBPs of Drosophila melanogaster and select OBPs from other Lepidoptera. We also evaluated the tissue specific expression of the M. sexta OBPs using an available RNAseq databases. In the four lepidopteran species, GOBP2 and all PBPs reside in single gene clusters; in two species GOBP1 is documented to be nearby, about 100 kb from the cluster; all GOBP/PBP genes share a common gene structure indicating a common origin. As such, the GOBP/PBP genes form a gene complex. Our findings suggest that (1) the lepidopteran GOBP/PBP complex is a monophyletic lineage with origins deep within Lepidoptera phylogeny, (2) within this lineage PBP gene evolution is much more dynamic than GOBP gene evolution, and (3) butterflies may have lost a PBP gene that plays an important role in moth pheromone detection, correlating with a shift from olfactory (moth) to visual (butterfly) communication, at least regarding long distance mate recognition. These findings will be clarified by additional lepidopteran genomic data, but the observation that moths and butterflies share most of the PBP/GOBP genes suggests that they also share common chemosensory-based behavioral pathways. Copyright © 2015 Elsevier Ltd. All rights reserved.

Peripheral and Central Olfactory Tuning in a Moth

PubMed Central

Ong, Rose C.

2012-01-01

Animals can be innately attracted to certain odorants. Because these attractants are particularly salient, they might be expected to induce relatively strong responses throughout the olfactory pathway, helping animals detect the most relevant odors but limiting flexibility to respond to other odors. Alternatively, specific neural wiring might link innately preferred odors to appropriate behaviors without a need for intensity biases. How nonpheromonal attractants are processed by the general olfactory system remains largely unknown. In the moth Manduca sexta, we studied this with a set of innately preferred host plant odors and other, neutral odors. Electroantennogram recordings showed that, as a population, olfactory receptor neurons (ORNs) did not respond with greater intensity to host plant odors, and further local field potential recordings showed that no specific amplification of signals induced by host plant odors occurred between the first olfactory center and the second. Moreover, when odorants were mutually diluted to elicit equally intense output from the ORNs, moths were able to learn to associate all tested odorants equally well with food reward. Together, these results suggest that, although nonpheromonal host plant odors activate broadly distributed responses, they may be linked to attractive behaviors mainly through specific wiring in the brain. PMID:22362866

Roles of specific membrane lipid domains in EGF receptor activation and cell adhesion molecule stabilization in a developing olfactory system.

PubMed

Gibson, Nicholas J; Tolbert, Leslie P; Oland, Lynne A

2009-09-29

Reciprocal interactions between glial cells and olfactory receptor neurons (ORNs) cause ORN axons entering the brain to sort, to fasciculate into bundles destined for specific glomeruli, and to form stable protoglomeruli in the developing olfactory system of an experimentally advantageous animal species, the moth Manduca sexta. Epidermal growth factor receptors (EGFRs) and the cell adhesion molecules (IgCAMs) neuroglian and fasciclin II are known to be important players in these processes. We report in situ and cell-culture studies that suggest a role for glycosphingolipid-rich membrane subdomains in neuron-glia interactions. Disruption of these subdomains by the use of methyl-beta-cyclodextrin results in loss of EGFR activation, depletion of fasciclin II in ORN axons, and loss of neuroglian stabilization in the membrane. At the cellular level, disruption leads to aberrant ORN axon trajectories, small antennal lobes, abnormal arrays of olfactory glomerul, and loss of normal glial cell migration. We propose that glycosphingolipid-rich membrane subdomains (possible membrane rafts or platforms) are essential for IgCAM-mediated EGFR activation and for anchoring of neuroglian to the cytoskeleton, both required for normal extension and sorting of ORN axons.

High specific activity enantiomerically enriched juvenile hormones: synthesis and binding assay.

PubMed Central

Prestwich, G D; Wawrzeńczyk, C

1985-01-01

A stereoselective total synthesis of chiral juvenile hormone I is described that allows stoichiometric introduction of two tritium atoms in the final step. Both optical antipodes of the pivotal epoxy alcohol intermediate were prepared in 95% enantiomeric excess by the Sharpless epoxidation of a (Z)-allylic alcohol. Elaboration of the hydroxy-methyl group to a vinyl group followed by selective homogeneous tritiation affords optically active juvenile hormone I analogs at 58 Ci/mmol. Competitive binding of the labeled 10R, 11S and 10S,11R enantiomers with unlabeled enantiomers to the hemolymph binding protein of Manduca sexta larvae was determined by using a dextran-coated charcoal assay. The natural 10R,11S enantiomer has twice the relative binding affinity of the 10S,11R enantiomer. The availability of such high specific activity optically pure hormones will contribute substantially to the search for high-affinity receptors for juvenile hormones in the nuclei of cells. Moreover, the chiral 12-hydroxy-(10R,11S)-epoxy intermediate allows modification of juvenile hormone for solid-phase biochemical and radioimmunochemical work without altering either the biologically important carbomethoxy or epoxy recognition sites. PMID:3860862

Chlorophyll degradation in the gut of generalist and specialist Lepidopteran caterpillars.

PubMed

Badgaa, Amarsanaa; Jia, Aiqun; Ploss, Kerstin; Boland, Wilhelm

2014-12-01

Plant feeding herbivores excrete most of the ingested chlorophyll (Chl) as partly degraded derivatives lacking the phytol side chain and the central magnesium ion. An ecological role of digested and degraded Chls in the interactions between insects, their food plant and other insects has been described recently. To gain more information on common degradation patterns in plant-feeding insects, the orals secretions and frass of five Lepidopteran caterpillars covering generalists and specialists, namely Spodoptera littoralis, Spodoptera eridania, Heliothis virescens, Helicoverpa armigera, Manduca sexta, and, for comparison, of the leaf beetle larva Chrysomela lapponica were analyzed for chlorophyll catabolites. The major degradation products were determined as pheohorbide a/b and pyropheophorbide a/b by using LC-MS, LC-NMR, UV, and fluorescence spectrometry. The compounds were not present in fresh leaves of the food plants (Phaseolus lunatus, Nicotiana tabacum). The catabolite spectrum in generalists and specialists was qualitatively similar and could be attributed to the action of gut proteins and the strongly alkaline milieu in the digestive tract. Due to the anaerobic environment of the larval gut, the tetrapyrrole core of the Chl catabolites was not cleaved. Substantial amounts of Chl a/b metabolites were strongly complexed by a protein in the mid-gut.

Characterization of a highly toxic strain of Bacillus thuringiensis serovar kurstaki very similar to the HD-73 strain.

PubMed

Reinoso-Pozo, Yaritza; Del Rincón-Castro, Ma Cristina; Ibarra, Jorge E

2016-09-01

The LBIT-1200 strain of Bacillus thuringiensis was recently isolated from soil, and showed a 6.4 and 9.5 increase in toxicity, against Manduca sexta and Trichoplusia ni, respectively, compared to HD-73. However, LBIT-1200 was still highly similar to HD-73, including the production of bipyramidal crystals containing only one protein of ∼130 000 kDa, its flagellin gene sequence related to the kurstaki serotype, plasmid and RepPCR patterns similar to HD-73, no production of β-exotoxin and no presence of VIP genes. Sequencing of its cry gene showed the presence of a cry1Ac-type gene with four amino acid differences, including two amino acid replacements in domain III, compared to Cry1Ac1, which may explain its higher toxicity. In conclusion, the LBIT-1200 strain is a variant of the HD-73 strain but shows a much higher toxicity, which makes this new strain an important candidate to be developed as a bioinsecticide, once it passes other tests, throughout its biotechnological development. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Unsteady flow challenges tracking performance at vortex shedding frequencies without disrupting lift mechanisms

NASA Astrophysics Data System (ADS)

Matthews, Megan; Sponberg, Simon

2017-11-01

Birds, insects, and many animals use unsteady aerodynamic mechanisms to achieve stable hovering flight. Natural environments are often characterized by unsteady flows causing animals to dynamically respond to perturbations while performing complex tasks, such as foraging. Little is known about how unsteady flow around an animal interacts with already unsteady flow in the environment or how this impacts performance. We study how the environment impacts maneuverability to reveal any coupling between body dynamics and aerodynamics for hawkmoths, Manduca sexta,tracking a 3D-printed robotic flower in a wind tunnel. We also observe the leading-edge vortex (LEV), a known lift-generating mechanism for insect flight with smoke visualization. Moths in still and unsteady air exhibit near perfect tracking at low frequencies, but tracking in the flower wake results in larger overshoot at mid-range. Smoke visualization of the flower wake shows that the dominant vortex shedding corresponds to the same frequency band as the increased overshoot. Despite the large effect on flight dynamics, the LEV remains bound to the wing and thorax throughout the wingstroke. In general, unsteady wind seems to decrease maneuverability, but LEV stability seems decoupled from changes in flight dynamics.

Multimodal Floral Signals and Moth Foraging Decisions

PubMed Central

Riffell, Jeffrey A.; Alarcón, Ruben

2013-01-01

Background Combinations of floral traits – which operate as attractive signals to pollinators – act on multiple sensory modalities. For Manduca sexta hawkmoths, how learning modifies foraging decisions in response to those traits remains untested, and the contribution of visual and olfactory floral displays on behavior remains unclear. Methodology/Principal Findings Using M. sexta and the floral traits of two important nectar resources in southwestern USA, Datura wrightii and Agave palmeri, we examined the relative importance of olfactory and visual signals. Natural visual and olfactory cues from D. wrightii and A. palmeri flowers permits testing the cues at their native intensities and composition – a contrast to many studies that have used artificial stimuli (essential oils, single odorants) that are less ecologically relevant. Results from a series of two-choice assays where the olfactory and visual floral displays were manipulated showed that naïve hawkmoths preferred flowers displaying both olfactory and visual cues. Furthermore, experiments using A. palmeri flowers – a species that is not very attractive to hawkmoths – showed that the visual and olfactory displays did not have synergistic effects. The combination of olfactory and visual display of D. wrightii, however – a flower that is highly attractive to naïve hawkmoths – did influence the time moths spent feeding from the flowers. The importance of the olfactory and visual signals were further demonstrated in learning experiments in which experienced moths, when exposed to uncoupled floral displays, ultimately chose flowers based on the previously experienced olfactory, and not visual, signals. These moths, however, had significantly longer decision times than moths exposed to coupled floral displays. Conclusions/Significance These results highlight the importance of specific sensory modalities for foraging hawkmoths while also suggesting that they learn the floral displays as combinatorial signals and use the integrated floral traits from their memory traces to mediate future foraging decisions. PMID:23991154

Fatty acid-amino acid conjugates are essential for systemic activation of salicylic acid-induced protein kinase and accumulation of jasmonic acid in Nicotiana attenuata.

PubMed

Hettenhausen, Christian; Heinrich, Maria; Baldwin, Ian T; Wu, Jianqiang

2014-11-28

Herbivory induces the activation of mitogen-activated protein kinases (MAPKs), the accumulation of jasmonates and defensive metabolites in damaged leaves and in distal undamaged leaves. Previous studies mainly focused on individual responses and a limited number of systemic leaves, and more research is needed for a better understanding of how different plant parts respond to herbivory. In the wild tobacco Nicotiana attenuata, FACs (fatty acid-amino acid conjugates) in Manduca sexta oral secretions (OS) are the major elicitors that induce herbivory-specific signaling but their role in systemic signaling is largely unknown. Here, we show that simulated herbivory (adding M. sexta OS to fresh wounds) dramatically increased SIPK (salicylic acid-induced protein kinase) activity and jasmonic acid (JA) levels in damaged leaves and in certain (but not all) undamaged systemic leaves, whereas wounding alone had no detectable systemic effects; importantly, FACs and wounding are both required for activating these systemic responses. In contrast to the activation of SIPK and elevation of JA in specific systemic leaves, increases in the activity of an important anti-herbivore defense, trypsin proteinase inhibitor (TPI), were observed in all systemic leaves after simulated herbivory, suggesting that systemic TPI induction does not require SIPK activation and JA increases. Leaf ablation experiments demonstrated that within 10 minutes after simulated herbivory, a signal (or signals) was produced and transported out of the treated leaves, and subsequently activated systemic responses. Our results reveal that N. attenuata specifically recognizes herbivore-derived FACs in damaged leaves and rapidly send out a long-distance signal to phylotactically connected leaves to activate MAPK and JA signaling, and we propose that FACs that penetrated into wounds rapidly induce the production of another long-distance signal(s) which travels to all systemic leaves and activates TPI defense.

Correlation analysis of symmetry breaking in the surface nanostructure ordering: case study of the ventral scale of the snake Morelia viridis

NASA Astrophysics Data System (ADS)

Kovalev, A.; Filippov, A.; Gorb, S. N.

2016-03-01

In contrast to the majority of inorganic or artificial materials, there is no ideal long-range ordering of structures on the surface in biological systems. Local symmetry of the ordering on biological surfaces is also often broken. In the present paper, the particular symmetry violation was analyzed for dimple-like nano-pattern on the belly scales of the skin of the pythonid snake Morelia viridis using correlation analysis and statistics of the distances between individual nanostructures. The results of the analysis performed on M. viridis were compared with a well-studied nano-nipple pattern on the eye of the sphingid moth Manduca sexta, used as a reference. The analysis revealed non-random, but very specific symmetry violation. In the case of the moth eye, the nano-nipple arrangement forms a set of domains, while in the case of the snake skin, the nano-dimples arrangement resembles an ordering of particles (molecules) in amorphous (glass) state. The function of the nano-dimples arrangement may be to provide both friction and strength isotropy of the skin. A simple model is suggested, which provides the results almost perfectly coinciding with the experimental ones. Possible mechanisms of the appearance of the above nano-formations are discussed.

Hematopoietic organs of Manduca sexta and hemocyte lineages.

PubMed

Nardi, James B; Pilas, Barbara; Ujhelyi, Elizabeth; Garsha, Karl; Kanost, Michael R

2003-10-01

Cells of the moth immune system are derived from organs that loosely envelop the four wing imaginal discs. The immune response in these insects is believed to depend on the activities of two main classes of hemocytes: plasmatocytes and granular cells. The fates of cells that arise from these hematopoietic organs have been followed by immunolabeling with plasmatocyte-specific and granular-cell-specific antibodies. Cells within each hematopoietic organ differ in their coherence and in their expression of two plasmatocyte-specific surface proteins, integrin and neuroglian. Within an organ there is no overlap in the expression of these two surface proteins; neuroglian is found on the surfaces of the coherent cells while integrin is expressed on cells that are losing coherence, rounding up, and dispersing. A granular-cell-specific marker for the protein lacunin labels the basal lamina that delimits each organ but only a small number of granular cells that lie on or near the periphery of the hematopoietic organ. When organs are cultured in the absence of hemolymph, all cells derived from hematopoietic organs turn out to immunolabel with the plasmatocyte-specific antibody MS13. The circulating plasmatocytes derived from hematopoietic organs have higher ploidy levels than the granular cells and represent a separate lineage of hemocytes.

Roles of Specific Membrane Lipid Domains in EGF Receptor Activation and Cell Adhesion Molecule Stabilization in a Developing Olfactory System

PubMed Central

Gibson, Nicholas J.; Tolbert, Leslie P.; Oland, Lynne A.

2009-01-01

Background Reciprocal interactions between glial cells and olfactory receptor neurons (ORNs) cause ORN axons entering the brain to sort, to fasciculate into bundles destined for specific glomeruli, and to form stable protoglomeruli in the developing olfactory system of an experimentally advantageous animal species, the moth Manduca sexta. Epidermal growth factor receptors (EGFRs) and the cell adhesion molecules (IgCAMs) neuroglian and fasciclin II are known to be important players in these processes. Methodology/Principal Findings We report in situ and cell-culture studies that suggest a role for glycosphingolipid-rich membrane subdomains in neuron-glia interactions. Disruption of these subdomains by the use of methyl-β-cyclodextrin results in loss of EGFR activation, depletion of fasciclin II in ORN axons, and loss of neuroglian stabilization in the membrane. At the cellular level, disruption leads to aberrant ORN axon trajectories, small antennal lobes, abnormal arrays of olfactory glomerul, and loss of normal glial cell migration. Conclusions/Significance We propose that glycosphingolipid-rich membrane subdomains (possible membrane rafts or platforms) are essential for IgCAM-mediated EGFR activation and for anchoring of neuroglian to the cytoskeleton, both required for normal extension and sorting of ORN axons. PMID:19787046

Synergism and Antagonism of Proximate Mechanisms Enable and Constrain the Response to Simultaneous Selection on Body Size and Development Time: An Empirical Test Using Experimental Evolution.

PubMed

Davidowitz, Goggy; Roff, Derek; Nijhout, H Frederik

2016-11-01

Natural selection acts on multiple traits simultaneously. How mechanisms underlying such traits enable or constrain their response to simultaneous selection is poorly understood. We show how antagonism and synergism among three traits at the developmental level enable or constrain evolutionary change in response to simultaneous selection on two focal traits at the phenotypic level. After 10 generations of 25% simultaneous directional selection on all four combinations of body size and development time in Manduca sexta (Sphingidae), the changes in the three developmental traits predict 93% of the response of development time and 100% of the response of body size. When the two focal traits were under synergistic selection, the response to simultaneous selection was enabled by juvenile hormone and ecdysteroids and constrained by growth rate. When the two focal traits were under antagonistic selection, the response to selection was due primarily to change in growth rate and constrained by the two hormonal traits. The approach used here reduces the complexity of the developmental and endocrine mechanisms to three proxy traits. This generates explicit predictions for the evolutionary response to selection that are based on biologically informed mechanisms. This approach has broad applicability to a diverse range of taxa, including algae, plants, amphibians, mammals, and insects.

Abdicating power for control: a precision timing strategy to modulate function of flight power muscles.

PubMed

Sponberg, S; Daniel, T L

2012-10-07

Muscles driving rhythmic locomotion typically show strong dependence of power on the timing or phase of activation. This is particularly true in insects' main flight muscles, canonical examples of muscles thought to have a dedicated power function. However, in the moth (Manduca sexta), these muscles normally activate at a phase where the instantaneous slope of the power-phase curve is steep and well below maximum power. We provide four lines of evidence demonstrating that, contrary to the current paradigm, the moth's nervous system establishes significant control authority in these muscles through precise timing modulation: (i) left-right pairs of flight muscles normally fire precisely, within 0.5-0.6 ms of each other; (ii) during a yawing optomotor response, left-right muscle timing differences shift throughout a wider 8 ms timing window, enabling at least a 50 per cent left-right power differential; (iii) timing differences correlate with turning torque; and (iv) the downstroke power muscles alone causally account for 47 per cent of turning torque. To establish (iv), we altered muscle activation during intact behaviour by stimulating individual muscle potentials to impose left-right timing differences. Because many organisms also have muscles operating with high power-phase gains (Δ(power)/Δ(phase)), this motor control strategy may be ubiquitous in locomotor systems.

Cloning and sequence analysis of Galleria mellonella juvenile hormone binding protein--a search for ancestors and relatives.

PubMed

Rodriguez Parkitna, Jan M; Ozyhar, Andrzej; Wiśniewski, Jacek R; Kochman, Marian

2002-09-01

Juvenile hormone binding proteins (JHBPs) serve as specific carriers of juvenile hormone (JH) in insect hemolymph. As shown in this report, Galleria mellonella JHBP is encoded by a cDNA of 1063 nucleotides. The pre-protein consists of 245 amino acids with a 20 amino acid leader sequence. The concentration of the JHBP mRNA reaches a maximum on the third day of the last larval instar, and decreases five-fold towards pupation. Comparison of amino acid sequences of JHBPs from Bombyx mori, Heliothis virescens, Manduca sexta and G. mellonella shows that 57 positions out of 226 are occupied by identical amino acids. A phylogeny tree was constructed from 32 proteins, which function could be associated to JH. It has three major branches: (i) ligand binding domains of nuclear receptors, (ii) JHBPs and JH esterases (JHEs), and (iii) hypothetical proteins found in Drosophila melanogaster genome. Despite the close positioning of JHEs and JHBPs on the tree, which probably arises from the presence of a common JH binding motif, these proteins are unlikely to belong to the same family. Detailed analysis of the secondary structure modeling shows that JHBPs may contain a beta-barrel motif flanked by alpha-helices and thus be evolutionary related to the same superfamily as calycins.

Larval leg integrity is maintained by Distal-less and is required for proper timing of metamorphosis in the flour beetle, Tribolium castaneum

PubMed Central

Suzuki, Yuichiro; Squires, Diego C.; Riddiford, Lynn M.

2009-01-01

The dramatic transformation from a larva to an adult must be accompanied by a coordinated activity of genes and hormones that enable an orchestrated transformation from larval to pupal/adult tissues. The maintenance of larval appendages and their subsequent transformation to appendages in holometabolous insects remains elusive at the developmental genetic level. Here the role of a key appendage patterning gene Distal-less (Dll) was examined in mid- to late- larval stages of the flour beetle, Tribolium castaneum. During late larval development, Dll was expressed in appendages in a similar manner as previously reported for the tobacco hornworm, Manduca sexta. Removal of this late Dll expression resulted in disruption of adult appendage patterning. Intriguingly, earlier removal resulted in dramatic loss of structural integrity and identity of larval appendages. A large amount of variability in appendage morphology was observed following Dll dsRNA injection, unlike larvae injected with dachshund dsRNA. These Dll dsRNA-injected larvae underwent numerous supernumerary molts, which could be terminated with injection of either JH methyltransferase or Methoprene-tolerant dsRNA. Apparently, the partial dedifferentiation of the appendages in these larvae acts to maintain high JH and, hence, prevents metamorphosis. PMID:19022238

High tunnels: protection for rather than from insect pests?

PubMed

Ingwell, Laura L; Thompson, Sarah L; Kaplan, Ian; Foster, Ricky E

2017-12-01

High tunnels are a season extension tool creating a hybrid of field and greenhouse growing conditions. High tunnels have recently increased in the USA and thus research on their management is lacking. One purported advantage of these structures is protection from common field pests, but evidence to support this claim is lacking. We compared insect pest populations in high tunnels with field production over two years for three crops: tomato, broccoli and cucumber. Greenhouse pests (e.g. aphids, whiteflies) were more prevalent in high tunnels, compared to field plots. Hornworms (tobacco (Manduca sexta L.) and tomato (M. quinquemaculata Haworth)), a common field pest on tomato, were also more abundant in high tunnels, requiring chemical control while field populations were low. The crucifer caterpillar complex (imported cabbageworm (Pieris rapae L.), diamondback moth (Plutella xylostella L.) and cabbage looper (Trichoplusia ni Hübner)) was also more abundant in high tunnels in 2010. Cucumber beetle (striped (Acalymma vittatum F.) and spotted (Diabrotica undecimpunctata Mannerheim)) densities were higher in high tunnels in 2010 and field plots in 2011. The common assumption that high tunnels offer protection from field pests was not supported. Instead, high tunnel growing conditions may facilitate higher pest populations. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Behavioral consequences of innate preferences and olfactory learning in hawkmoth–flower interactions

PubMed Central

Riffell, Jeffrey A.; Alarcón, Ruben; Abrell, Leif; Davidowitz, Goggy; Bronstein, Judith L.; Hildebrand, John G.

2008-01-01

Spatiotemporal variability in floral resources can have ecological and evolutionary consequences for both plants and the pollinators on which they depend. Seldom, however, can patterns of flower abundance and visitation in the field be linked with the behavioral mechanisms that allow floral visitors to persist when a preferred resource is scarce. To explore these mechanisms better, we examined factors controlling floral preference in the hawkmoth Manduca sexta in the semiarid grassland of Arizona. Here, hawkmoths forage primarily on flowers of the bat-adapted agave, Agave palmeri, but shift to the moth-adapted flowers of their larval host plant, Datura wrightii, when these become abundant. Both plants emit similar concentrations of floral odor, but scent composition, nectar, and flower reflectance are distinct between the two species, and A. palmeri flowers provide six times as much chemical energy as flowers of D. wrightii. Behavioral experiments with both naïve and experienced moths revealed that hawkmoths learn to feed from agave flowers through olfactory conditioning but readily switch to D. wrightii flowers, for which they are the primary pollinator, based on an innate odor preference. Behavioral flexibility and the olfactory contrast between flowers permit the hawkmoths to persist within a dynamic environment, while at the same time to function as the major pollinator of one plant species. PMID:18305169

Abdicating power for control: a precision timing strategy to modulate function of flight power muscles

PubMed Central

Sponberg, S.; Daniel, T. L.

2012-01-01

Muscles driving rhythmic locomotion typically show strong dependence of power on the timing or phase of activation. This is particularly true in insects' main flight muscles, canonical examples of muscles thought to have a dedicated power function. However, in the moth (Manduca sexta), these muscles normally activate at a phase where the instantaneous slope of the power–phase curve is steep and well below maximum power. We provide four lines of evidence demonstrating that, contrary to the current paradigm, the moth's nervous system establishes significant control authority in these muscles through precise timing modulation: (i) left–right pairs of flight muscles normally fire precisely, within 0.5–0.6 ms of each other; (ii) during a yawing optomotor response, left—right muscle timing differences shift throughout a wider 8 ms timing window, enabling at least a 50 per cent left–right power differential; (iii) timing differences correlate with turning torque; and (iv) the downstroke power muscles alone causally account for 47 per cent of turning torque. To establish (iv), we altered muscle activation during intact behaviour by stimulating individual muscle potentials to impose left—right timing differences. Because many organisms also have muscles operating with high power–phase gains (Δpower/Δphase), this motor control strategy may be ubiquitous in locomotor systems. PMID:22833272

Cloning and expression of chitinases of Entamoebae.

PubMed

de la Vega, H; Specht, C A; Semino, C E; Robbins, P W; Eichinger, D; Caplivski, D; Ghosh, S; Samuelson, J

1997-04-01

Entamoeba histolytica (Eh) and Entamoeba dispar (Ed) are protozoan parasites that infect hundreds of millions of persons. In the colonic lumen, amebae form chitin-walled cysts, the infectious stage of the parasite. Entamoeba invadens (Ei), which infects reptiles and is a model for amebic encystation, produces chitin synthase and chitinase during encystation. Ei cysts formation is blocked by the chitinase-inhibitor allosamidin. Here molecular cloning techniques were used to identify homologous genes of Eh, Ed, and Ei that encode chitinases (EC 3.2.1.14). The Eh gene (Eh cht1) predicts a 507-amino acid (aa) enzyme, which has 93 and 74% positional identities with Ed and Ei chitinases, respectively. The Entamoeba chitinases have signal sequences, followed by acidic and hydrophilic sequences composed of multiple tandemly arranged 7-aa repeats (Eh and Ed) or repeats varying in length (Ei). The aa compositions of the chitinase repeats are similar to those of the repeats of the Eh and Ed Ser-rich proteins. The COOH-terminus of each chitinase has a catalytic domain, which resembles those of Brugia malayi (33% positional identity) and Manduca sexta (29%). Recombinant entamoeba chitinases are precipitated by chitin and show chitinase activity with chitooligosacharide substrates. Consistent with previous biochemical data, chitinase mRNAs are absent in Ei trophozoites and accumulate to maximal levels in Ei encysting for 48 h.

Food restriction alters energy allocation strategy during growth in tobacco hornworms ( Manduca sexta larvae)

NASA Astrophysics Data System (ADS)

Jiao, Lihong; Amunugama, Kaushalya; Hayes, Matthew B.; Jennings, Michael; Domingo, Azriel; Hou, Chen

2015-08-01

Growing animals must alter their energy budget in the face of environmental changes and prioritize the energy allocation to metabolism for life-sustaining requirements and energy deposition in new biomass growth. We hypothesize that when food availability is low, larvae of holometabolic insects with a short development stage (relative to the low food availability period) prioritize biomass growth at the expense of metabolism. Driven by this hypothesis, we develop a simple theoretical model, based on conservation of energy and allometric scaling laws, for understanding the dynamic energy budget of growing larvae under food restriction. We test the hypothesis by manipulative experiments on fifth instar hornworms at three temperatures. At each temperature, food restriction increases the scaling power of growth rate but decreases that of metabolic rate, as predicted by the hypothesis. During the fifth instar, the energy budgets of larvae change dynamically. The free-feeding larvae slightly decrease the energy allocated to growth as body mass increases and increase the energy allocated to life sustaining. The opposite trends were observed in food restricted larvae, indicating the predicted prioritization in the energy budget under food restriction. We compare the energy budgets of a few endothermic and ectothermic species and discuss how different life histories lead to the differences in the energy budgets under food restriction.

Cloning of soluble alkaline phosphatase cDNA and molecular basis of the polymorphic nature in alkaline phosphatase isozymes of Bombyx mori midgut.

PubMed

Itoh, M; Kanamori, Y; Takao, M; Eguchi, M

1999-02-01

A cDNA coding for soluble type alkaline phosphatase (sALP) of Bombyx mori was isolated. Deduced amino acid sequence showed high identities to various ALPs and partial similarities to ATPase of Manduca sexta. Using this cDNA sequence as a probe, the molecular basis of electrophoretic polymorphism in sALP and membrane-bound type ALP (mALP) was studied. As for mALP, the result suggested that post-translational modification was important for the proteins to express activity and to represent their extensive polymorphic nature, whereas the magnitude of activities was mainly regulated by transcription. On the other hand, sALP zymogram showed poor polymorphism, but one exception was the null mutant, in which the sALP gene was largely lost. Interestingly, the sALP gene was shown to be transcribed into two mRNAs of different sizes, 2.0 and 2.4 Kb. In addition to the null mutant of sALP, we found a null mutant for mALP. Both of these mutants seem phenotypically silent, suggesting that the functional differentiation between these isozymes is not perfect, so that they can still work mutually and complement each other as an indispensable enzyme for B. mori.

Characterization of the complete mitochondrial genome of the giant silkworm moth, Eriogyna pyretorum (Lepidoptera: Saturniidae).

PubMed

Jiang, Shao-Tong; Hong, Gui-Yun; Yu, Miao; Li, Na; Yang, Ying; Liu, Yan-Qun; Wei, Zhao-Jun

2009-05-22

The complete mitochondrial genome (mitogenome) of Eriogyna pyretorum (Lepidoptera: Saturniidae) was determined as being composed of 15,327 base pairs (bp), including 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and a control region. The arrangement of the PCGs is the same as that found in the other sequenced lepidopteran. The AT skewness for the E. pyretorum mitogenome is slightly negative (-0.031), indicating the occurrence of more Ts than As. The nucleotide composition of the E. pyretorum mitogenome is also biased toward A + T nucleotides (80.82%). All PCGs are initiated by ATN codons, except for cytochrome c oxidase subunit 1 and 2 (cox1 and cox2). Two of the 13 PCGs harbor the incomplete termination codon by T. All tRNA genes have a typical clover-leaf structure of mitochondrial tRNA, with the exception of trnS1(AGN) and trnS2(UCN). Phylogenetic analysis among the available lepidopteran species supports the current morphology-based hypothesis that Bombycoidea, Geometroidea, Notodontidea, Papilionoidea and Pyraloidea are monophyletic. As has been previously suggested, Bombycidae (Bombyx mori and Bombyx mandarina), Sphingoidae (Manduca sexta) and Saturniidae (Antheraea pernyi, Antheraea yamamai, E. pyretorum and Caligula boisduvalii) formed a group.

Characterization of the complete mitochondrial genome of the giant silkworm moth, Eriogyna pyretorum (Lepidoptera: Saturniidae)

PubMed Central

Jiang, Shao-Tong; Hong, Gui-Yun; Yu, Miao; Li, Na; Yang, Ying; Liu, Yan-Qun; Wei, Zhao-Jun

2009-01-01

The complete mitochondrial genome (mitogenome) of Eriogyna pyretorum (Lepidoptera: Saturniidae) was determined as being composed of 15,327 base pairs (bp), including 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and a control region. The arrangement of the PCGs is the same as that found in the other sequenced lepidopteran. The AT skewness for the E. pyretorum mitogenome is slightly negative (-0.031), indicating the occurrence of more Ts than As. The nucleotide composition of the E. pyretorum mitogenome is also biased toward A + T nucleotides (80.82%). All PCGs are initiated by ATN codons, except for cytochrome c oxidase subunit 1 and 2 (cox1 and cox2). Two of the 13 PCGs harbor the incomplete termination codon by T. All tRNA genes have a typical clover-leaf structure of mitochondrial tRNA, with the exception of trnS1(AGN) and trnS2(UCN). Phylogenetic analysis among the available lepidopteran species supports the current morphology-based hypothesis that Bombycoidea, Geometroidea, Notodontidea, Papilionoidea and Pyraloidea are monophyletic. As has been previously suggested, Bombycidae (Bombyx mori and Bombyx mandarina), Sphingoidae (Manduca sexta) and Saturniidae (Antheraea pernyi, Antheraea yamamai, E. pyretorum and Caligula boisduvalii) formed a group. PMID:19471586

Insect eggs protected from high temperatures by limited homeothermy of plant leaves.

PubMed

Potter, Kristen; Davidowitz, Goggy; Woods, H Arthur

2009-11-01

Virtually all aspects of insect biology are affected by body temperature, and many taxa have evolved sophisticated temperature-control mechanisms. All insects, however, begin life as eggs and lack the ability to thermoregulate. Eggs laid on leaves experience a thermal environment, and thus a body temperature, that is strongly influenced by the leaves themselves. Because plants can maintain leaf temperatures that differ from ambient, e.g. by evapotranspiration, plant hosts may protect eggs from extreme ambient temperatures. We examined the degree to which leaves buffer ambient thermal variation and whether that buffering benefits leaf-associated insect eggs. In particular, we: (1) measured temperature variation at oviposition sites in the field, (2) manipulated temperatures in the laboratory to determine the effect of different thermal conditions on embryo development time and survival, and (3) tested embryonic metabolic rates over increasing temperatures. Our results show that Datura wrightii leaves buffer Manduca sexta eggs from fatally high ambient temperatures in the southwestern USA. Moreover, small differences in temperature profiles among leaves can cause large variation in egg metabolic rate and development time. Specifically, large leaves were hotter than small leaves during the day, reaching temperatures that are stressfully high for eggs. This study provides the first mechanistic demonstration of how this type of leaf-constructed thermal refuge interacts with egg physiology.

More than just sugar: allocation of nectar amino acids and fatty acids in a Lepidopteran.

PubMed

Levin, Eran; McCue, Marshall D; Davidowitz, Goggy

2017-02-08

The ability to allocate resources, even when limited, is essential for survival and fitness. We examine how nutrients that occur in minute amounts are allocated among reproductive, somatic, and metabolic demands. In addition to sugar, flower nectars contain two macronutrients-amino acids and fatty acids. We created artificial nectars spiked with 13 C-labelled amino acids and fatty acids and fed these to adult moths (Manduca sexta: Sphingidae) to understand how they allocate these nutrients among competing sinks (reproduction, somatic tissue, and metabolic fuel). We found that both essential and non-essential amino acids were allocated to eggs and flight muscles and were still detectable in early-instar larvae. Parental-derived essential amino acids were more conserved in the early-instars than non-essential amino acids. All amino acids were used as metabolic fuel, but the non-essential amino acids were oxidized at higher rates than essential amino acids. Surprisingly, the nectar fatty acids were not vertically transferred to offspring, but were readily used as a metabolic fuel by the moth, minimizing losses of endogenous nutrient stores. We conclude that the non-carbohydrate components of nectar may play important roles in both reproductive success and survival of these nectar-feeding animals. © 2017 The Author(s).

More than just sugar: allocation of nectar amino acids and fatty acids in a Lepidopteran

PubMed Central

McCue, Marshall D.; Davidowitz, Goggy

2017-01-01

The ability to allocate resources, even when limited, is essential for survival and fitness. We examine how nutrients that occur in minute amounts are allocated among reproductive, somatic, and metabolic demands. In addition to sugar, flower nectars contain two macronutrients—amino acids and fatty acids. We created artificial nectars spiked with 13C-labelled amino acids and fatty acids and fed these to adult moths (Manduca sexta: Sphingidae) to understand how they allocate these nutrients among competing sinks (reproduction, somatic tissue, and metabolic fuel). We found that both essential and non-essential amino acids were allocated to eggs and flight muscles and were still detectable in early-instar larvae. Parental-derived essential amino acids were more conserved in the early-instars than non-essential amino acids. All amino acids were used as metabolic fuel, but the non-essential amino acids were oxidized at higher rates than essential amino acids. Surprisingly, the nectar fatty acids were not vertically transferred to offspring, but were readily used as a metabolic fuel by the moth, minimizing losses of endogenous nutrient stores. We conclude that the non-carbohydrate components of nectar may play important roles in both reproductive success and survival of these nectar-feeding animals. PMID:28148746

Tracking fluid-borne odors in diverse and dynamic environments using multiple sensory mechanisms

NASA Astrophysics Data System (ADS)

Taylor, Brian Kyle

The ability to locate odor sources in different types of environments (i.e. diverse) and environments that change radically during the mission (i.e., dynamic) is essential. While many engineered odor tracking systems have been developed, they appear to be designed for a particular environment (e.g., strong or low flow). In field conditions, agents may encounter both. Insect olfactory orientation studies show that several animals can locate odor sources in both high and low flow environments, and environments where the wind vanishes during tracking behavior. Furthermore, animals use multi-modal sensing, including olfaction, vision and touch to localize a source. This work uses simulated and hardware environments to explore how engineered systems can maintain wind-driven tracking behavior in diverse and dynamic environments. The simulation uses olfaction, vision and tactile attributes to track and localize a source in the following environments: high flow, low flow, and transition from high to low flow (i.e., Wind Stop). The hardware platform tests two disparate tracking strategies (including the simulated strategy) in an environment that transitions from strong to low flow. Results indicate that using a remembered wind direction post wind-shutoff is a viable way to maintain wind-driven tracking behavior in a wind stop environment, which can help bridge the gap between high flow and low flow strategies. Also, multi-modal sensing with tactile attributes, vision and olfaction helps a vehicle to localize a source. In addition to engineered systems, the moth Manduca sexta is challenged to track in the following environments: Wind and Odor, Wind Stop, Odor and No Wind, No Odor and No Wind to gain a better understanding of animal behavior in these environments. Results show that contrary to previous studies of different moth species, M. sexta does not generally maintain its wind-driven tracking behavior post-wind shutoff, but instead executes a stereotyped sequence of maneuvers followed by odor-modulated undirected exploration of its environment. In the Odor and No Wind environment, animals become biased towards the area of the arena where odor is located compared to the No Odor and No Wind environment. Robot and animal results are compared to learn more about both.

Gait control in a soft robot by sensing interactions with the environment using self-deformation.

PubMed

Umedachi, Takuya; Kano, Takeshi; Ishiguro, Akio; Trimmer, Barry A

2016-12-01

All animals use mechanosensors to help them move in complex and changing environments. With few exceptions, these sensors are embedded in soft tissues that deform in normal use such that sensory feedback results from the interaction of an animal with its environment. Useful information about the environment is expected to be embedded in the mechanical responses of the tissues during movements. To explore how such sensory information can be used to control movements, we have developed a soft-bodied crawling robot inspired by a highly tractable animal model, the tobacco hornworm Manduca sexta . This robot uses deformations of its body to detect changes in friction force on a substrate. This information is used to provide local sensory feedback for coupled oscillators that control the robot's locomotion. The validity of the control strategy is demonstrated with both simulation and a highly deformable three-dimensionally printed soft robot. The results show that very simple oscillators are able to generate propagating waves and crawling/inching locomotion through the interplay of deformation in different body parts in a fully decentralized manner. Additionally, we confirmed numerically and experimentally that the gait pattern can switch depending on the surface contact points. These results are expected to help in the design of adaptable, robust locomotion control systems for soft robots and also suggest testable hypotheses about how soft animals use sensory feedback.

Gait control in a soft robot by sensing interactions with the environment using self-deformation

PubMed Central

Ishiguro, Akio; Trimmer, Barry A.

2016-01-01

All animals use mechanosensors to help them move in complex and changing environments. With few exceptions, these sensors are embedded in soft tissues that deform in normal use such that sensory feedback results from the interaction of an animal with its environment. Useful information about the environment is expected to be embedded in the mechanical responses of the tissues during movements. To explore how such sensory information can be used to control movements, we have developed a soft-bodied crawling robot inspired by a highly tractable animal model, the tobacco hornworm Manduca sexta. This robot uses deformations of its body to detect changes in friction force on a substrate. This information is used to provide local sensory feedback for coupled oscillators that control the robot's locomotion. The validity of the control strategy is demonstrated with both simulation and a highly deformable three-dimensionally printed soft robot. The results show that very simple oscillators are able to generate propagating waves and crawling/inching locomotion through the interplay of deformation in different body parts in a fully decentralized manner. Additionally, we confirmed numerically and experimentally that the gait pattern can switch depending on the surface contact points. These results are expected to help in the design of adaptable, robust locomotion control systems for soft robots and also suggest testable hypotheses about how soft animals use sensory feedback. PMID:28083114

An integrated analysis of phenotypic selection on insect body size and development time.

PubMed

Eck, Daniel J; Shaw, Ruth G; Geyer, Charles J; Kingsolver, Joel G

2015-09-01

Most studies of phenotypic selection do not estimate selection or fitness surfaces for multiple components of fitness within a unified statistical framework. This makes it difficult or impossible to assess how selection operates on traits through variation in multiple components of fitness. We describe a new generation of aster models that can evaluate phenotypic selection by accounting for timing of life-history transitions and their effect on population growth rate, in addition to survival and reproductive output. We use this approach to estimate selection on body size and development time for a field population of the herbivorous insect, Manduca sexta (Lepidoptera: Sphingidae). Estimated fitness surfaces revealed strong and significant directional selection favoring both larger adult size (via effects on egg counts) and more rapid rates of early larval development (via effects on larval survival). Incorporating the timing of reproduction and its influence on population growth rate into the analysis resulted in larger values for size in early larval development at which fitness is maximized, and weaker selection on size in early larval development. These results illustrate how the interplay of different components of fitness can influence selection on size and development time. This integrated modeling framework can be readily applied to studies of phenotypic selection via multiple fitness components in other systems. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Biobotic insect swarm based sensor networks for search and rescue

NASA Astrophysics Data System (ADS)

Bozkurt, Alper; Lobaton, Edgar; Sichitiu, Mihail; Hedrick, Tyson; Latif, Tahmid; Dirafzoon, Alireza; Whitmire, Eric; Verderber, Alexander; Marin, Juan; Xiong, Hong

2014-06-01

The potential benefits of distributed robotics systems in applications requiring situational awareness, such as search-and-rescue in emergency situations, are indisputable. The efficiency of such systems requires robotic agents capable of coping with uncertain and dynamic environmental conditions. For example, after an earthquake, a tremendous effort is spent for days to reach to surviving victims where robotic swarms or other distributed robotic systems might play a great role in achieving this faster. However, current technology falls short of offering centimeter scale mobile agents that can function effectively under such conditions. Insects, the inspiration of many robotic swarms, exhibit an unmatched ability to navigate through such environments while successfully maintaining control and stability. We have benefitted from recent developments in neural engineering and neuromuscular stimulation research to fuse the locomotory advantages of insects with the latest developments in wireless networking technologies to enable biobotic insect agents to function as search-and-rescue agents. Our research efforts towards this goal include development of biobot electronic backpack technologies, establishment of biobot tracking testbeds to evaluate locomotion control efficiency, investigation of biobotic control strategies with Gromphadorhina portentosa cockroaches and Manduca sexta moths, establishment of a localization and communication infrastructure, modeling and controlling collective motion by learning deterministic and stochastic motion models, topological motion modeling based on these models, and the development of a swarm robotic platform to be used as a testbed for our algorithms.

Olfactory modulation by dopamine in the context of aversive learning

PubMed Central

Riffell, Jeffrey A.; Martin, Joshua P.; Gage, Stephanie L.; Nighorn, Alan J.

2012-01-01

The need to detect and process sensory cues varies in different behavioral contexts. Plasticity in sensory coding can be achieved by the context-specific release of neuromodulators in restricted brain areas. The context of aversion triggers the release of dopamine in the insect brain, yet the effects of dopamine on sensory coding are unknown. In this study, we characterize the morphology of dopaminergic neurons that innervate each of the antennal lobes (ALs; the first synaptic neuropils of the olfactory system) of the moth Manduca sexta and demonstrate with electrophysiology that dopamine enhances odor-evoked responses of the majority of AL neurons while reducing the responses of a small minority. Because dopamine release in higher brain areas mediates aversive learning we developed a naturalistic, ecologically inspired aversive learning paradigm in which an innately appetitive host plant floral odor is paired with a mimic of the aversive nectar of herbivorized host plants. This pairing resulted in a decrease in feeding behavior that was blocked when dopamine receptor antagonists were injected directly into the ALs. These results suggest that a transient dopaminergic enhancement of sensory output from the AL contributes to the formation of aversive memories. We propose a model of olfactory modulation in which specific contexts trigger the release of different neuromodulators in the AL to increase olfactory output to downstream areas of processing. PMID:22552185

Preliminary study on quality evaluation of pecans with terahertz time-domain spectroscopy

NASA Astrophysics Data System (ADS)

Li, Bin; Cao, Wei; Mathanker, Sunil; Zhang, Weili; Wang, Ning

2010-11-01

This paper reports a preliminary work on a feasibility study of applying terahertz (THz) technology for pecan quality evaluation. A set of native pecan nuts collected in 2009 were used during the experiment. Each pecan nutmeat was manually sliced at a thickness of about 1mm, 2mm, and 3mm and a size of about 2cm (length) ×1cm (width). Pecan shell and inner separator were also cut into the same size. The absorption spectra for the nutmeat slices, shell, and inner separator were collected using a THz time-domain spectroscopy (THz-TDS) developed by a group of researchers at Oklahoma State University. The test results show that nutmeat, shell, and inner separator had different absorption characteristics within the bandwidth of 0.2-2.0 THz. To study the capability of insect damage detection of the THz spectroscopy, the absorption spectra of insects (living manduca sexta and dry pecan weevil) were also collected. Due to high water contents in the insects, very obvious spectral characteristics were found. The results from the preliminary study show a potential of THz technology applied for quality detection of bio-products. However, since bio-products mostly have high water content and are handled under an environment with certain levels of water content, practical issues needs to be further investigated to make the THz technology a feasible tool for quality evaluation.

VP7: an attachment protein of bluetongue virus for cellular receptors in Culicoides variipennis.

PubMed

Xu, G; Wilson, W; Mecham, J; Murphy, K; Zhou, E M; Tabachnick, W

1997-07-01

The importance of VP7 of bluetongue virus (BTV) in the binding of BTV to membrane proteins of the BTV vector Culicoides variipennis was investigated. Core BTV particles, prepared from whole viruses, lacked outer proteins VP2 and VP5 and had VP7 exposed. More core particles and whole viruses bound to membrane preparations of adults of C. variipennis and KC cells, which were cultured from this vector insect, than to membrane preparations of Manduca sexta larvae. More core particles than whole viruses bound to membrane preparations of adults of C. variipennis and KC cells. Polyclonal anti-idiotypic antibodies (anti-Id), which were made against an antigen-combining region of an anti-BTV-10 VP7 antibody and functionally mimicked VP7, bound more to the membrane preparations of adults of C. variipennis and KC cells, and less to cytosol preparations. In Western overalay analysis, the Culicoides plasma membrane preparation reduced binding of an anti-VP7 monoclonal antibody to VP7. Whole and core BTV particles and the anti-Id bound to a membrane protein with a molecular mass of 23 kDa that was present predominantly in membrane preparations of adults of C. variipennis and KC cells. This protein was present in much lower concentrations in membrane preparations of C6/36 and DM-2 insect cells.

Molecular cloning of the tomato Hairless gene implicates actin dynamics in trichome-mediated defense and mechanical properties of stem tissue

DOE PAGES

Kang, Jin-Ho; Campos, Marcelo L.; Zemelis-Durfee, Starla; ...

2016-07-31

Trichomes are epidermal structures that provide a first line of defense against arthropod herbivores. The recessive hairless (hl) mutation in tomato (Solanum lycopersicum L.) causes severe distortion of trichomes on all aerial tissues, impairs the accumulation of sesquiterpene and polyphenolic compounds in glandular trichomes, and compromises resistance to the specialist herbivore Manduca sexta. Here, we demonstrate that the tomato Hl gene encodes a subunit (SRA1) of the highly conserved WAVE regulatory complex that controls nucleation of actin filaments in a wide range of eukaryotic cells. The tomato SRA1 gene spans a 42-kb region containing both Solyc11g013280 and Solyc11g013290. The hlmore » mutation corresponds to a complex 3-kb deletion that removes the last exon of the gene. Expression of a wild-type SRA1 cDNA in the hl mutant background restored normal trichome development, accumulation of glandular trichomederived metabolites, and resistance to insect herbivory. These findings thus establish a role for SRA1 in the development of tomato trichomes and also implicate the actin-cytoskeleton network in cytosolic control of specialized metabolism for plant defense. We also show that the brittleness of hl mutant stems is associated with altered mechanical and cell morphological properties of stem tissue, and demonstrate that this defect is directly linked to the mutation in SRA1.« less

Molecular cloning of the tomato Hairless gene implicates actin dynamics in trichome-mediated defense and mechanical properties of stem tissue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Jin-Ho; Campos, Marcelo L.; Zemelis-Durfee, Starla

Trichomes are epidermal structures that provide a first line of defense against arthropod herbivores. The recessive hairless (hl) mutation in tomato (Solanum lycopersicum L.) causes severe distortion of trichomes on all aerial tissues, impairs the accumulation of sesquiterpene and polyphenolic compounds in glandular trichomes, and compromises resistance to the specialist herbivore Manduca sexta. Here, we demonstrate that the tomato Hl gene encodes a subunit (SRA1) of the highly conserved WAVE regulatory complex that controls nucleation of actin filaments in a wide range of eukaryotic cells. The tomato SRA1 gene spans a 42-kb region containing both Solyc11g013280 and Solyc11g013290. The hlmore » mutation corresponds to a complex 3-kb deletion that removes the last exon of the gene. Expression of a wild-type SRA1 cDNA in the hl mutant background restored normal trichome development, accumulation of glandular trichomederived metabolites, and resistance to insect herbivory. These findings thus establish a role for SRA1 in the development of tomato trichomes and also implicate the actin-cytoskeleton network in cytosolic control of specialized metabolism for plant defense. We also show that the brittleness of hl mutant stems is associated with altered mechanical and cell morphological properties of stem tissue, and demonstrate that this defect is directly linked to the mutation in SRA1.« less

Molecular characterization of an Apolipophorin-III gene from the Chinese oak silkworm, Antheraea pernyi (Lepidoptera: Saturniidae).

PubMed

Liu, Qiu-Ning; Lin, Kun-Zhang; Yang, Lin-Nan; Dai, Li-Shang; Wang, Lei; Sun, Yu; Qian, Cen; Wei, Guo-Qing; Liu, Dong-Ran; Zhu, Bao-Jian; Liu, Chao-Liang

2015-03-01

Apolipophorin-III (ApoLp-III) acts in lipid transport, lipoprotein metabolism, and innate immunity in insects. In this study, an ApoLp-III gene of Antheraea pernyi pupae (Ap-ApoLp-III) was isolated and characterized. The full-length cDNA of Ap-ApoLp-III is 687 bp, including a 5'-untranslated region (UTR) of 40 bp, 3'-UTR of 86 bp and an open reading frame of 561 bp encoding a polypeptide of 186 amino acids that contains an Apolipophorin-III precursor domain (PF07464). The deduced Ap-apoLp-III protein sequence has 68, 59, and 23% identity with its orthologs of Manduca sexta, Bombyx mori, and Aedes aegypti, respectively. Phylogenetic analysis showed that the Ap-apoLp-III was close to that of Bombycoidea. qPCR analysis revealed that Ap-ApoLp-III expressed during the four developmental stages and in integument, fat body, and ovaries. After six types of microorganism infections, expression levels of the Ap-ApoLp-III gene were upregulated significantly at different time points compared with control. RNA interference (RNAi) of Ap-ApoLp-III showed that the expression of Ap-ApoLp-III was significantly downregulated using qPCR after injection of E. coli. We infer that the Ap-ApoLp-III gene acts in the innate immunity of A. pernyi. © 2014 Wiley Periodicals, Inc.

Metabolism of an insect diuretic hormone by Malpighian tubules studied by liquid chromatography coupled with electrospray ionization mass spectrometry

PubMed Central

Li, Hong; Wang, Houle; Schegg, Kathleen M.; Schooley, David A.

1997-01-01

The larger of two diuretic hormones of the tobacco hornworm, Manduca sexta, (Mas-DH) is a peptide of 41 residues. It is one of a family of seven currently known insect diuretic hormones that are similar to the corticotropin-releasing factor–urotensin–sauvagine family of peptides. We investigated the possible inactivation of Mas-DH by incubating it in vitro with larval Malpighian tubules (Mt), the target organ of the hormone. The medium was analyzed, and degradation products were identified, using on-line microbore reversed-phase liquid chromatography coupled to electrospray ionization mass spectrometry (RPLC-ESI-MS). This sensitive technique allows identification of metabolites of Mas-DH (present at an initial level of ≈1 μM). An accurate Mr value for a metabolite is usually sufficient for unambiguous identification. Mas-DH is cleaved by Mt proteases initially at L29–R30 and R30–A31 under our assay conditions; some Mas-DH is also oxidized, apparently at M2 and M11. The proteolysis can be inhibited by 5 mM EDTA, suggesting that divalent metals are needed for peptide cleavage. The oxidation of the hormone can be inhibited by catalase or 1 mM methionine, indicating that H2O2 or related reactive oxygen species are responsible for the oxidative degradation observed. RPLC-ESI-MS is shown here to be an elegant and efficient method for studying peptide hormone metabolism resulting from unknown proteases and pathways. PMID:9391048

The development of wing shape in Lepidoptera: mitotic density, not orientation, is the primary determinant of shape.

PubMed

Nijhout, H Frederik; Cinderella, Margaret; Grunert, Laura W

2014-03-01

The wings of butterflies and moths develop from imaginal disks whose structure is always congruent with the final adult wing. It is therefore possible to map every point on the imaginal disk to a location on the adult wing throughout ontogeny. We studied the growth patterns of the wings of two distantly related species with very different adult wing shapes, Junonia coenia and Manduca sexta. The shape of the wing disks change throughout their growth phase in a species-specific pattern. We measured mitotic densities and mitotic orientation in successive stages of wing development approximately one cell division apart. Cell proliferation was spatially patterned, and the density of mitoses was highly correlated with local growth. Unlike other systems in which the direction of mitoses has been viewed as the primary determinant of directional growth, we found that in these two species the direction of growth was only weakly correlated with the orientation of mitoses. Directional growth appears to be imposed by a constantly changing spatial pattern of cell division coupled with a weak bias in the orientation of cell division. Because growth and cell division in imaginal disk require ecdysone and insulin signaling, the changing spatial pattern of cell division may due to a changing pattern of expression of receptors or downstream elements in the signaling pathways for one or both of these hormones. Evolution of wing shape comes about by changes in the progression of spatial patterns of cell division. © 2014 Wiley Periodicals, Inc.

Molecular cloning of the tomato Hairless gene implicates actin dynamics in trichome-mediated defense and mechanical properties of stem tissue.

PubMed

Kang, Jin-Ho; Campos, Marcelo L; Zemelis-Durfee, Starla; Al-Haddad, Jameel M; Jones, A Daniel; Telewski, Frank W; Brandizzi, Federica; Howe, Gregg A

2016-10-01

Trichomes are epidermal structures that provide a first line of defense against arthropod herbivores. The recessive hairless (hl) mutation in tomato (Solanum lycopersicum L.) causes severe distortion of trichomes on all aerial tissues, impairs the accumulation of sesquiterpene and polyphenolic compounds in glandular trichomes, and compromises resistance to the specialist herbivore Manduca sexta Here, we demonstrate that the tomato Hl gene encodes a subunit (SRA1) of the highly conserved WAVE regulatory complex that controls nucleation of actin filaments in a wide range of eukaryotic cells. The tomato SRA1 gene spans a 42-kb region containing both Solyc11g013280 and Solyc11g013290 The hl mutation corresponds to a complex 3-kb deletion that removes the last exon of the gene. Expression of a wild-type SRA1 cDNA in the hl mutant background restored normal trichome development, accumulation of glandular trichome-derived metabolites, and resistance to insect herbivory. These findings establish a role for SRA1 in the development of tomato trichomes and also implicate the actin-cytoskeleton network in cytosolic control of specialized metabolism for plant defense. We also show that the brittleness of hl mutant stems is associated with altered mechanical and cell morphological properties of stem tissue, and demonstrate that this defect is directly linked to the mutation in SRA1. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Structure and expression of sulfatase and sulfatase modifying factor genes in the diamondback moth, Plutella xylostella.

PubMed

Ma, Xiao-Li; He, Wei-Yi; Chen, Wei; Xu, Xue-Jiao; Qi, Wei-Ping; Zou, Ming-Min; You, Yan-Chun; Baxter, Simon W; Wang, Ping; You, Min-Sheng

2017-06-01

The diamondback moth, Plutella xylostella (L.), uses sulfatases (SULF) to counteract the glucosinolate-myrosinase defensive system that cruciferous plants have evolved to deter insect feeding. Sulfatase activity is regulated by post-translational modification of a cysteine residue by sulfatase modifying factor 1 (SUMF1). We identified 12 SULF genes (PxylSulfs) and two SUMF1 genes (PxylSumf1s) in the P. xylostella genome. Phylogenetic analysis of SULFs and SUMFs from P. xylostella, Bombyx mori, Manduca sexta, Heliconius melpomene, Danaus plexippus, Drosophila melanogaster, Tetranychus urticae and Homo sapiens showed that the SULFs were clustered into five groups, and the SUMFs could be divided into two groups. Profiling of the expression of PxylSulfs and PxylSumfs by RNA-seq and by quantitative real-time polymerase chain reaction showed that two glucosinolate sulfatase genes (GSS), PxylSulf2 and PxylSulf3, were primarily expressed in the midgut of 3rd- and 4th-instar larvae. Moreover, expression of sulfatases PxylSulf2, PxylSulf3 and PxylSulf4 were correlated with expression of the sulfatases modifying factor PxylSumf1a. The findings from this study provide new insights into the structure and expression of SUMF1 and PxylSulf genes that are considered to be key factors for the evolutionary success of P. xylostella as a specialist herbivore of cruciferous plants. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Resistance to Bacillus thuringiensis by the Indian meal moth, Plodia interpunctella: comparison of midgut proteinases from susceptible and resistant larvae.

PubMed

Johnson, D E; Brookhart, G L; Kramer, K J; Barnett, B D; McGaughey, W H

1990-03-01

Midgut homogenates from susceptible and resistant strains of the Indian meal moth, Plodia interpunctella, were compared for their ability to activate the entomocidal parasporal crystal protein from Bacillus thuringiensis. The properties of midgut proteinases from both types of larvae were also examined. Electrophoretic patterns of crystal protein from B. thuringiensis subspecies kurstaki (HD-1) and aizawai (HD-133 and HD-144) were virtually unchanged following digestion by either type of midgut homogenate. Changes in pH (9.5 to 11.5) or midgut homogenate concentration during digestion failed to substantially alter protein electrophoretic patterns of B. thuringiensis HD-1 crystal toxin. In vitro toxicity of crystal protein activated by either type of midgut preparation was equal toward cultured insect cells from either Manduca sexta or Choristoneura fumiferana. Electrophoresis of midgut extracts in polyacrylamide gels containing gelatin as substrate also yielded matching mobility patterns of proteinases from both types of midguts. Quantitation of midgut proteolytic activity using tritiated casein as a substrate revealed variation between midgut preparations, but no statistically significant differences between proteolytic activities from susceptible and resistant Indian meal moth larvae. Inhibition studies indicated that a trypsin-like proteinase with maximal activity at pH 10 is a major constituent of Indian meal moth midguts. The results demonstrated that midguts from susceptible and resistant strains of P. interpunctella are similar both in their ability to activate B. thuringiensis protoxin and in their proteolytic activity.

Development of a stained cell nuclei counting system

NASA Astrophysics Data System (ADS)

Timilsina, Niranjan; Moffatt, Christopher; Okada, Kazunori

2011-03-01

This paper presents a novel cell counting system which exploits the Fast Radial Symmetry Transformation (FRST) algorithm [1]. The driving force behind our system is a research on neurogenesis in the intact nervous system of Manduca Sexta or the Tobacco Hornworm, which was being studied to assess the impact of age, food and environment on neurogenesis. The varying thickness of the intact nervous system in this species often yields images with inhomogeneous background and inconsistencies such as varying illumination, variable contrast, and irregular cell size. For automated counting, such inhomogeneity and inconsistencies must be addressed, which no existing work has done successfully. Thus, our goal is to devise a new cell counting algorithm for the images with non-uniform background. Our solution adapts FRST: a computer vision algorithm which is designed to detect points of interest on circular regions such as human eyes. This algorithm enhances the occurrences of the stained-cell nuclei in 2D digital images and negates the problems caused by their inhomogeneity. Besides FRST, our algorithm employs standard image processing methods, such as mathematical morphology and connected component analysis. We have evaluated the developed cell counting system with fourteen digital images of Tobacco Hornworm's nervous system collected for this study with ground-truth cell counts by biology experts. Experimental results show that our system has a minimum error of 1.41% and mean error of 16.68% which is at least forty-four percent better than the algorithm without FRST.

Differential protection of Cry1Fa toxin against Spodoptera frugiperda larval gut proteases by cadherin orthologs correlates with increased synergism.

PubMed

Rahman, Khalidur; Abdullah, Mohd Amir F; Ambati, Suresh; Taylor, Milton D; Adang, Michael J

2012-01-01

The Cry proteins produced by Bacillus thuringiensis (Bt) are the most widely used biopesticides effective against a range of crop pests and disease vectors. Like chemical pesticides, development of resistance is the primary threat to the long-term efficacy of Bt toxins. Recently discovered cadherin-based Bt Cry synergists showed the potential to augment resistance management by improving efficacy of Cry toxins. However, the mode of action of Bt Cry synergists is thus far unclear. Here we elucidate the mechanism of cadherin-based Cry toxin synergism utilizing two cadherin peptides, Spodoptera frugiperda Cad (SfCad) and Manduca sexta Cad (MsCad), which differentially enhance Cry1Fa toxicity to Spodoptera frugiperda neonates. We show that differential SfCad- and MsCad-mediated protection of Cry1Fa toxin in the Spodoptera frugiperda midgut correlates with differential Cry1Fa toxicity enhancement. Both peptides exhibited high affinity for Cry1Fa toxin and an increased rate of Cry1Fa-induced pore formation in S. frugiperda. However, only SfCad bound the S. frugiperda brush border membrane vesicle and more effectively prolonged the stability of Cry1Fa toxin in the gut, explaining higher Cry1Fa enhancement by this peptide. This study shows that cadherin fragments may enhance B. thuringiensis toxicity by at least two different mechanisms or a combination thereof: (i) protection of Cry toxin from protease degradation in the insect midgut and (ii) enhancement of pore-forming ability of Cry toxin.

Changes in mitochondrial electron transport chain activity during insect metamorphosis.

PubMed

Chamberlin, M E

2007-02-01

The midgut of the tobacco hornworm (Manduca sexta) is a highly aerobic tissue that is destroyed by programmed cell death during larval-pupal metamorphosis. The death of the epithelium begins after commitment to pupation, and the oxygen consumption of isolated midgut mitochondria decreases soon after commitment. To assess the role of the electron transport chain in this decline in mitochondrial function, the maximal activities of complexes I-IV of the respiratory chain were measured in isolated midgut mitochondria. Whereas there were no developmental changes in the activity of complex I or III, activities of complexes II and IV [cytochrome c oxidase (COX)] were higher in mitochondria from precommitment than postcommitment larvae. This finding is consistent with a higher rate of succinate oxidation in mitochondria isolated from precommitment larvae and reveals that the metamorphic decline in mitochondrial respiration is due to the targeted destruction or inactivation of specific sites within the mitochondria, rather than the indiscriminate destruction of the organelles. The COX turnover number (e- x s(-1) x cytochrome aa3(-1)) was greater for the enzyme from precommitment than postcommitment larvae, indicating a change in the enzyme structure and/or its lipid environment during the early stages of metamorphosis. The turnover number of COX in the intact mitochondria (in organello COX) was also lower in postcommitment larvae. In addition to changes in the protein or membrane phospholipids, the metamorphic decline in this rate constant may be a result of the observed loss of endogenous cytochrome c.

Activation of glial FGFRs is essential in glial migration, proliferation, and survival and in glia-neuron signaling during olfactory system development.

PubMed

Gibson, Nicholas J; Tolbert, Leslie P; Oland, Lynne A

2012-01-01

Development of the adult olfactory system of the moth Manduca sexta depends on reciprocal interactions between olfactory receptor neuron (ORN) axons growing in from the periphery and centrally-derived glial cells. Early-arriving ORN axons induce a subset of glial cells to proliferate and migrate to form an axon-sorting zone, in which later-arriving ORN axons will change their axonal neighbors and change their direction of outgrowth in order to travel with like axons to their target areas in the olfactory (antennal) lobe. These newly fasciculated axon bundles will terminate in protoglomeruli, the formation of which induces other glial cells to migrate to surround them. Glial cells do not migrate unless ORN axons are present, axons fail to fasciculate and target correctly without sufficient glial cells, and protoglomeruli are not maintained without a glial surround. We have shown previously that Epidermal Growth Factor receptors and the IgCAMs Neuroglian and Fasciclin II play a role in the ORN responses to glial cells. In the present work, we present evidence for the importance of glial Fibroblast Growth Factor receptors in glial migration, proliferation, and survival in this developing pathway. We also report changes in growth patterns of ORN axons and of the dendrites of olfactory (antennal lobe) neurons following blockade of glial FGFR activation that suggest that glial FGFR activation is important in reciprocal communication between neurons and glial cells.

Activation of Glial FGFRs Is Essential in Glial Migration, Proliferation, and Survival and in Glia-Neuron Signaling during Olfactory System Development

PubMed Central

Gibson, Nicholas J.; Tolbert, Leslie P.; Oland, Lynne A.

2012-01-01

Development of the adult olfactory system of the moth Manduca sexta depends on reciprocal interactions between olfactory receptor neuron (ORN) axons growing in from the periphery and centrally-derived glial cells. Early-arriving ORN axons induce a subset of glial cells to proliferate and migrate to form an axon-sorting zone, in which later-arriving ORN axons will change their axonal neighbors and change their direction of outgrowth in order to travel with like axons to their target areas in the olfactory (antennal) lobe. These newly fasciculated axon bundles will terminate in protoglomeruli, the formation of which induces other glial cells to migrate to surround them. Glial cells do not migrate unless ORN axons are present, axons fail to fasciculate and target correctly without sufficient glial cells, and protoglomeruli are not maintained without a glial surround. We have shown previously that Epidermal Growth Factor receptors and the IgCAMs Neuroglian and Fasciclin II play a role in the ORN responses to glial cells. In the present work, we present evidence for the importance of glial Fibroblast Growth Factor receptors in glial migration, proliferation, and survival in this developing pathway. We also report changes in growth patterns of ORN axons and of the dendrites of olfactory (antennal lobe) neurons following blockade of glial FGFR activation that suggest that glial FGFR activation is important in reciprocal communication between neurons and glial cells. PMID:22493675

Sodium Solute Symporter and Cadherin Proteins Act as Bacillus thuringiensis Cry3Ba Toxin Functional Receptors in Tribolium castaneum*

PubMed Central

Contreras, Estefanía; Schoppmeier, Michael; Real, M. Dolores; Rausell, Carolina

2013-01-01

Understanding how Bacillus thuringiensis (Bt) toxins interact with proteins in the midgut of susceptible coleopteran insects is crucial to fully explain the molecular bases of Bt specificity and insecticidal action. In this work, aminopeptidase N (TcAPN-I), E-cadherin (TcCad1), and sodium solute symporter (TcSSS) have been identified by ligand blot as putative Cry3Ba toxin-binding proteins in Tribolium castaneum (Tc) larvae. RNA interference knockdown of TcCad1 or TcSSS proteins resulted in decreased susceptibility to Cry3Ba toxin, demonstrating the Cry toxin receptor functionality for these proteins. In contrast, TcAPN-I silencing had no effect on Cry3Ba larval toxicity, suggesting that this protein is not relevant in the Cry3Ba toxin mode of action in Tc. Remarkable features of TcSSS protein were the presence of cadherin repeats in its amino acid sequence and that a TcSSS peptide fragment containing a sequence homologous to a binding epitope found in Manduca sexta and Tenebrio molitor Bt cadherin functional receptors enhanced Cry3Ba toxicity. This is the first time that the involvement of a sodium solute symporter protein as a Bt functional receptor has been demonstrated. The role of this novel receptor in Bt toxicity against coleopteran insects together with the lack of receptor functionality of aminopeptidase N proteins might account for some of the differences in toxin specificity between Lepidoptera and Coleoptera insect orders. PMID:23645668

Manduca rustica (Lepidoptera: Sphingidae) damage on olive (Olea europaea;Lamiales:Oleaceae)trees in Florida

USDA-ARS?s Scientific Manuscript database

The rustic sphinx, Manduca rustica has been identified as an occasional pest for olive, Olea europaea, in Florida. This pest’s distribution spans Florida’s olive growing region from the northern panhandle as far south as Polk County....

Neuroglian is expressed on cells destined to form the prothoracic glands of Manduca embryos as they segregate from surrounding cells and rearrange during morphogenesis.

PubMed

Chen, C L; Lampe, D J; Robertson, H M; Nardi, J B

1997-01-01

A cell surface protein (3B11) is differentially expressed in the embryonic labial segment of Manduca as two circular monolayers of epithelial cells invaginate and segregate from surrounding epithelial cells. The cells that invaginate and preferentially express 3B11 represent the presumptive prothoracic glands. These cells continue to express protein 3B11 as they rearrange to form first a three-dimensional aggregate and later anastomosing filaments of cells. In the differentiated prothoracic gland, expression of 3B11 is restricted to sites of cell-cell contact. Cloning and sequencing of the cDNA for protein 3B11 revealed that this protein is the Manduca counterpart of Drosophila neuroglian and mouse L1. These surface proteins are known to function as adhesion/recognition molecules during development. Manduca neuroglian shares 58 and 31% identity respectively with the Drosophila and mouse proteins and has a cytoplasmic domain of over 100 amino acids.

HSPRO Controls Early Nicotiana attenuata Seedling Growth during Interaction with the Fungus Piriformospora indica1[C][W][OA

PubMed Central

Schuck, Stefan; Camehl, Iris; Gilardoni, Paola A.; Oelmueller, Ralf; Baldwin, Ian T.; Bonaventure, Gustavo

2012-01-01

In a previous study aimed at identifying regulators of Nicotiana attenuata responses against chewing insects, a 26-nucleotide tag matching the HSPRO (ORTHOLOG OF SUGAR BEET Hs1pro-1) gene was found to be strongly induced after simulated herbivory (Gilardoni et al., 2010). Here we characterized the function of HSPRO during biotic interactions in transgenic N. attenuata plants silenced in its expression (ir-hspro). In wild-type plants, HSPRO expression was not only induced during simulated herbivory but also when leaves were inoculated with Pseudomonas syringae pv tomato DC3000 and roots with the growth-promoting fungus Piriformospora indica. Reduced HSPRO expression did not affect the regulation of direct defenses against Manduca sexta herbivory or P. syringae pv tomato DC3000 infection rates. However, reduced HSPRO expression positively influenced early seedling growth during interaction with P. indica; fungus-colonized ir-hspro seedlings increased their fresh biomass by 30% compared with the wild type. Grafting experiments demonstrated that reduced HSPRO expression in roots was sufficient to induce differential growth promotion in both roots and shoots. This effect was accompanied by changes in the expression of 417 genes in colonized roots, most of which were metabolic genes. The lack of major differences in the metabolic profiles of ir-hspro and wild-type colonized roots (as analyzed by liquid chromatography time-of-flight mass spectrometry) suggested that accelerated metabolic rates were involved. We conclude that HSPRO participates in a whole-plant change in growth physiology when seedlings interact with P. indica. PMID:22892352

Structural and functional basis of amino acid specificity in the invertebrate cotransporter KAAT1

PubMed Central

Miszner, Andreea; Peres, Antonio; Castagna, Michela; Bettè, Sara; Giovannardi, Stefano; Cherubino, Francesca; Bossi, Elena

2007-01-01

The substrate specificity of KAAT1, a Na+- and K+-dependent neutral amino acid cotransporter cloned from the larva of the invertebrate Manduca sexta and belonging to the SLC6A gene family has been investigated using electrophysiological and radiotracer methods. The specificity of KAAT1 was compared to that of CAATCH1, a strictly related transporter with different amino acid selectivity. Competition experiments between different substrates indicate that both transporters bind leucine more strongly than threonine and proline, the difference between KAAT1 and CAATCH1 residing in the incapacity of the latter to complete the transport cycle in presence of leucine. The behaviour of CAATCH1 is mimicked by the S308T mutant form of KAAT1, constructed on the basis of the atomic structure of a leucine-transporting bacterial member of the family, which indicates the participation of this residue in the leucine-binding site. The reverse mutation T308S in CAATCH1 conferred to this transporter the ability to transport leucine in presence of K+. These results may be interpreted by a kinetic scheme in which, in presence of Na+, the leucine-bound state of the transporter is relatively stable, while in presence of K+ and at negative potentials the progression of the leucine-bound form along the cycle is favoured. In this context serine 308 appears to be important in allowing the change to the inward-facing conformation of the transporter following substrate binding, rather than in determining the binding specificity. PMID:17412764

An antibiotic produced by an insect-pathogenic bacterium suppresses host defenses through phenoloxidase inhibition

PubMed Central

Eleftherianos, Ioannis; Boundy, Sam; Joyce, Susan A.; Aslam, Shazia; Marshall, James W.; Cox, Russell J.; Simpson, Thomas J.; Clarke, David J.; ffrench-Constant, Richard H.; Reynolds, Stuart E.

2007-01-01

Photorhabdus is a virulent pathogen that kills its insect host by overcoming immune responses. The bacterium also secretes a range of antibiotics to suppress the growth of other invading microorganisms. Here we show that Photorhabdus produces a small-molecule antibiotic (E)-1,3-dihydroxy-2-(isopropyl)-5-(2-phenylethenyl)benzene (ST) that also acts as an inhibitor of phenoloxidase (PO) in the insect host Manduca sexta. The Photorhabdus gene stlA encodes an enzyme that produces cinnamic acid, a key precursor for production of ST, and a mutation in stlA results in loss of ST production and PO inhibitory activity, which are both restored by genetic complementation of the mutant and also by supplying cinnamic acid. ST is produced both in vitro and in vivo in sufficient quantities to account for PO inhibition and is the only detectable solvent-extractable inhibitor. A Photorhabdus stlA− mutant is significantly less virulent, proliferates slower within the host, and provokes the formation of significantly more melanotic nodules than wild-type bacteria. Virulence of the stlA− mutant is also rescued by supplying cinnamic acid. The proximate cause of the virulence effect, however, is the inhibition of PO, because the effect of the stlA− mutation on virulence is abolished in insects in which PO has been knocked down by RNA interference (RNAi). Thus, ST has a dual function both as a PO inhibitor to counter host immune reactions and also as an antibiotic to exclude microbial competitors from the insect cadaver. PMID:17284598

Flight motor networks modulate primary olfactory processing in the moth Manduca sexta.

PubMed

Chapman, Phillip D; Burkland, Rex; Bradley, Samual P; Houot, Benjamin; Bullman, Victoria; Dacks, Andrew M; Daly, Kevin C

2018-05-22

Nervous systems must distinguish sensory signals derived from an animal's own movements (reafference) from environmentally derived sources (exafference). To accomplish this, motor networks producing reafference transmit motor information, via a corollary discharge circuit (CDC), to affected sensory networks, modulating sensory function during behavior. While CDCs have been described in most sensory modalities, none have been observed projecting to an olfactory pathway. In moths, two mesothoracic to deutocerebral histaminergic neurons (MDHns) project from flight sensorimotor centers in the mesothoracic neuromere to the antennal lobe (AL), where they provide the sole source of histamine (HA), but whether they represent a CDC is unknown. We demonstrate that MDHn spiking activity is positively correlated with wing-motor output and increased before bouts of motor activity, suggesting that MDHns communicate global locomotor state, rather than providing a precisely timed motor copy. Within the AL, HA application sharpened entrainment of projection neuron responses to odor stimuli embedded within simulated wing-beat-induced flows, whereas MDHn axotomy or AL HA receptor (HA-r) blockade reduced entrainment. This finding is consistent with higher-order CDCs, as the MDHns enhanced rather than filtered entrainment of AL projection neurons. Finally, HA-r blockade increased odor detection and discrimination thresholds in behavior assays. These results establish MDHns as a CDC that modulates AL temporal resolution, enhancing odor-guided behavior. MDHns thus appear to represent a higher-order CDC to an insect olfactory pathway; this CDC's unique nature highlights the importance of motor-to-sensory signaling as a context-specific mechanism that fine-tunes sensory function. Copyright © 2018 the Author(s). Published by PNAS.

The vacuolar protein sorting genes in insects: A comparative genome view.

PubMed

Li, Zhaofei; Blissard, Gary

2015-07-01

In eukaryotic cells, regulated vesicular trafficking is critical for directing protein transport and for recycling and degradation of membrane lipids and proteins. Through carefully regulated transport vesicles, the endomembrane system performs a large and important array of dynamic cellular functions while maintaining the integrity of the cellular membrane system. Genetic studies in yeast Saccharomyces cerevisiae have identified approximately 50 vacuolar protein sorting (VPS) genes involved in vesicle trafficking, and most of these genes are also characterized in mammals. The VPS proteins form distinct functional complexes, which include complexes known as ESCRT, retromer, CORVET, HOPS, GARP, and PI3K-III. Little is known about the orthologs of VPS proteins in insects. Here, with the newly annotated Manduca sexta genome, we carried out genomic comparative analysis of VPS proteins in yeast, humans, and 13 sequenced insect genomes representing the Orders Hymenoptera, Diptera, Hemiptera, Phthiraptera, Lepidoptera, and Coleoptera. Amino acid sequence alignments and domain/motif structure analyses reveal that most of the components of ESCRT, retromer, CORVET, HOPS, GARP, and PI3K-III are evolutionarily conserved across yeast, insects, and humans. However, in contrast to the VPS gene expansions observed in the human genome, only four VPS genes (VPS13, VPS16, VPS33, and VPS37) were expanded in the six insect Orders. Additionally, VPS2 was expanded only in species from Phthiraptera, Lepidoptera, and Coleoptera. These studies provide a baseline for understanding the evolution of vesicular trafficking across yeast, insect, and human genomes, and also provide a basis for further addressing specific functional roles of VPS proteins in insects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evidence for common horizontal transmission of Wolbachia among butterflies and moths.

PubMed

Ahmed, Muhammad Z; Breinholt, Jesse W; Kawahara, Akito Y

2016-05-27

Wolbachia is one of the most widespread bacteria on Earth. Previous research on Wolbachia-host interactions indicates that the bacterium is typically transferred vertically, from mother to offspring, through the egg cytoplasm. Although horizontal transmission of Wolbachia from one species to another is reported to be common in arthropods, limited direct ecological evidence is available. In this study, we examine horizontal transmission of Wolbachia using a multilocus sequence typing (MLST) strains dataset and used Wolbachia and Lepidoptera genomes to search for evidence for lateral gene transfer (LGT) in Lepidoptera, one of the most diverse cosmopolitan insect orders. We constructed a phylogeny of arthropod-associated MLST Wolbachia strains and calibrated the age of Wolbachia strains associated with lepidopteran species. Our results reveal inter-specific, inter-generic, inter-familial, and inter-ordinal horizontal transmission of Wolbachia strains, without discernible geographic patterns. We found at least seven probable cases of horizontal transmission among 31 species within Lepidoptera and between Lepidoptera and other arthropod hosts. The divergence time analysis revealed that Wolbachia is recently (22.6-4.7 mya, 95 % HPD) introduced in Lepidoptera. Analysis of nine Lepidoptera genomes (Bombyx mori, Danaus plexippus, Heliconius melpomene, Manduca sexta, Melitaea cinxia, Papilio glaucus, P. polytes, P. xuthus and Plutella xylostella) yielded one possible instance of Wolbachia LGT. Our results provide evidence of high incidence of identical and multiple strains of Wolbachia among butterflies and moths, adding Lepidoptera to the growing body of evidence for common horizontal transmission of Wolbachia. This study demonstrates interesting dynamics of this remarkable and influential microorganism.

Bowman-Birk proteinase inhibitor from Cajanus cajan seeds: purification, characterization, and insecticidal properties.

PubMed

Prasad, Elaprolu R; Merzendorfer, H; Madhurarekha, C; Dutta-Gupta, A; Padmasree, K

2010-03-10

A red gram proteinase inhibitor (RgPI) was purified from red gram ( Cajanus cajan ) seeds by using ammonium sulfate precipitation and ion-exchange, affinity, and gel filtration chromatography. SDS-PAGE under nonreducing condition revealed two protein bands with molecular masses of approximately 8.5 and approximately 16.5 kDa corresponding to monomeric and dimeric forms of RgPI, respectively. Similarly, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry also confirmed the presence of dimer as well as other oligomeric forms: trimer, tetramer, and pentamer. Reduction of RgPI with dithiothreitol (DTT) led to the dissociation of the dimeric and oligomeric forms. Native-PAGE and two-dimensional gel electrophoresis indicated the existence of isoinhibitors with pI values of 5.95, 6.25, 6.50, 6.90, and 7.15, respectively. The MALDI-TOF-TOF mass spectrum and N-terminal sequence 'DQHHSSKACC' suggested that the isolated RgPI is a member of the Bowman-Birk inhibitor family. RgPI exhibited noncompetitive type inhibitory activity against bovine pancreatic trypsin and chymotrypsin, with inhibition constants of 292 and 2265 nM, respectively. It was stable up to a temperature of 80 degrees C and was active over a wide pH range between 2 and 12. However, reduction with DTT or 2-mercaptoethanol resulted in loss of inhibitory activity against trypsin and chymotrypsin. It also decreased the activity of larval midgut trypsin-like proteinases in Manduca sexta . Its insecticidal property was further confirmed by reduction in the growth and development of these larvae, when supplemented in the diet.

Carnivore Attractant or Plant Elicitor? Multifunctional Roles of Methyl Salicylate Lures in Tomato Defense.

PubMed

Rowen, Elizabeth; Gutensohn, Michael; Dudareva, Natalia; Kaplan, Ian

2017-06-01

Synthetic plant volatile lures attract natural enemies, but may have non-target effects due to the multifunctional nature of volatile signals. For example, methyl salicylate (MeSA) is used to attract predators, yet also serves as a signaling hormone involved in plant pathogen defense. We investigated the consequences of deploying MeSA lures to attract predators for tomato (Solanum lycopersicum) defense against herbivores. To understand the spatial distribution of the lure's effect, we exposed tomatoes in the field to MeSA along a linear distance gradient and induced defenses by simulating feeding by hornworm caterpillars in a fully crossed factorial design (+/- MeSA, +/- herbivory). Subsequently, we analyzed activity of several defensive proteins (protease inhibitors, polyphenol oxidase, peroxidase), development of hornworm larvae (Manduca sexta), growth of fungal pathogens (Cladosporium and Alternaria), and attractiveness to herbivores and predators. Overall, MeSA-exposed plants were more resistant to both insects and pathogens. Secondary pathogen infection was reduced by 25% in MeSA exposed plants, possibly due to elevated polyphenol oxidase activity. Interestingly, we found that lures affected plant pathogen defenses equivalently across all distances (up to 4 m away) indicating that horizontal diffusion of a synthetic volatile may be greater than previously assumed. While thrips avoided colonizing hornworm- damaged tomato plants, this induced resistance was not observed upon pre-exposure to MeSA, suggesting that MeSA suppresses the repellant effect induced by herbivory. Thus, using MeSA lures in biological control may inadvertently protect crops from pathogens, but has mixed effects on plant resistance to insect herbivores.

Non-linear blend coding in the moth antennal lobe emerges from random glomerular networks

PubMed Central

Capurro, Alberto; Baroni, Fabiano; Olsson, Shannon B.; Kuebler, Linda S.; Karout, Salah; Hansson, Bill S.; Pearce, Timothy C.

2012-01-01

Neural responses to odor blends often exhibit non-linear interactions to blend components. The first olfactory processing center in insects, the antennal lobe (AL), exhibits a complex network connectivity. We attempt to determine if non-linear blend interactions can arise purely as a function of the AL network connectivity itself, without necessitating additional factors such as competitive ligand binding at the periphery or intrinsic cellular properties. To assess this, we compared blend interactions among responses from single neurons recorded intracellularly in the AL of the moth Manduca sexta with those generated using a population-based computational model constructed from the morphologically based connectivity pattern of projection neurons (PNs) and local interneurons (LNs) with randomized connection probabilities from which we excluded detailed intrinsic neuronal properties. The model accurately predicted most of the proportions of blend interaction types observed in the physiological data. Our simulations also indicate that input from LNs is important in establishing both the type of blend interaction and the nature of the neuronal response (excitation or inhibition) exhibited by AL neurons. For LNs, the only input that significantly impacted the blend interaction type was received from other LNs, while for PNs the input from olfactory sensory neurons and other PNs contributed agonistically with the LN input to shape the AL output. Our results demonstrate that non-linear blend interactions can be a natural consequence of AL connectivity, and highlight the importance of lateral inhibition as a key feature of blend coding to be addressed in future experimental and computational studies. PMID:22529799

cDNA cloning and sequence determination of the pheromone biosynthesis activating neuropeptide from the seabuckthorn carpenterworm, Holcocerus hippophaecolus (Lepidoptera: Cossidae).

PubMed

Li, Juan; Zhou, Jiao; Sun, Rongbo; Zhang, Haolin; Zong, Shixiang; Luo, Youqing; Sheng, Xia; Weng, Qiang

2013-04-01

The PBAN (pheromone biosynthesis activating neuropeptide)/pyrokinin peptides comprise a major neuropeptide family characterized by a common FXPRL amide at the C-terminus. These peptides are actively involved in many essential endocrine functions. For the first time, we reported the cDNA cloning and sequence determination of the PBAN from the seabuckthorn carpenterworm, Holcocerus hippophaecolus, by using rapid amplification of cDNA ends. The full-length cDNA of Hh-DH-PBAN contained five peptides: diapause hormone (DH) homolog, α-neuropeptide (NP), β-NP, PBAN, and γ-NP. All of the peptides were amidated at their C-terminus and shared a conserved motif, FXPR (or K) L. Moreover, Hh-DH-PBAN had high homology to the other members of the PBAN peptide family: 56% with Manduca sexta, 66% with Bombyx mori, 77% with Helicoverpa zea, and 47% with Plutella xylostella. Phylogenetic analysis revealed that Hh-DH-PBAN was closely related to PBANs from Noctuidae, demonstrated by the relatively higher similarity compared with H. zea. In addition, real-time quantitative PCR (qRT-PCR) analysis showed that Hh-DH-PBAN mRNA expression peaked in the brain-subesophageal ganglion (Br-SOG) complex, and was also detected at high levels during larval and adult stages. The expression decreased significantly after pupation. These results provided information concerning molecular structure characteristics of Hh-DH-PBAN, whose expression profile suggested that the Hh-DH-PBAN gene might be correlated with larval development and sex pheromone biosynthesis in females of the H. hippophaecolus. 2013 Wiley Periodicals, Inc

The 20-hydroxyecdysone-induced signalling pathway in G2/M arrest of Plodia interpunctella imaginal wing cells.

PubMed

Siaussat, David; Bozzolan, Françoise; Porcheron, Patrick; Debernard, Stéphane

2008-05-01

The mechanisms involved in the control of cellular proliferation by the steroid hormone 20-hydroxyecdysone (20E) in insects are not known. We dissected the 20E signalling pathway responsible for G2/M arrest of imaginal cells from the IAL-PID2 cells of the Indian meal moth Plodia interpunctella. We first used a 5'-3' RACE-based strategy to clone a 4479bp cDNA encoding a putative P. interpunctella HR3 transcription factor named PiHR3. The deduced amino acid sequence of PiHR3 was highly similar to those of HR3 proteins from other lepidopterans, e.g. Manduca sexta and Bombyx mori. Using double-stranded RNA-mediated interference (dsRNAi), we then succeeded in blocking the ability of 20E to induce the expression of PiEcR-B1, PiUSP-2 and PiHR3 genes that encode the P. interpunctella ecdysone receptor B1-isoform, Ultraspiracle-2 isoform, the insect homologue of the vertebrate retinoid X receptor, and the HR3 transcription factor. We showed that inhibiting the 20E induction of PiEcR-B1, PiUSP-2 and PiHR3 mRNAs prevented the decreased expression of B cyclin and consequently the G2/M arrest of IAL-PID2 cells. Using this functional approach, we revealed the participation of EcR, USP and HR3 in a 20E signalling pathway that controls the proliferation of imaginal cells by regulating the expression of B cyclin.

Differential Protection of Cry1Fa Toxin against Spodoptera frugiperda Larval Gut Proteases by Cadherin Orthologs Correlates with Increased Synergism

PubMed Central

Rahman, Khalidur; Abdullah, Mohd Amir F.; Ambati, Suresh; Taylor, Milton D.

2012-01-01

The Cry proteins produced by Bacillus thuringiensis (Bt) are the most widely used biopesticides effective against a range of crop pests and disease vectors. Like chemical pesticides, development of resistance is the primary threat to the long-term efficacy of Bt toxins. Recently discovered cadherin-based Bt Cry synergists showed the potential to augment resistance management by improving efficacy of Cry toxins. However, the mode of action of Bt Cry synergists is thus far unclear. Here we elucidate the mechanism of cadherin-based Cry toxin synergism utilizing two cadherin peptides, Spodoptera frugiperda Cad (SfCad) and Manduca sexta Cad (MsCad), which differentially enhance Cry1Fa toxicity to Spodoptera frugiperda neonates. We show that differential SfCad- and MsCad-mediated protection of Cry1Fa toxin in the Spodoptera frugiperda midgut correlates with differential Cry1Fa toxicity enhancement. Both peptides exhibited high affinity for Cry1Fa toxin and an increased rate of Cry1Fa-induced pore formation in S. frugiperda. However, only SfCad bound the S. frugiperda brush border membrane vesicle and more effectively prolonged the stability of Cry1Fa toxin in the gut, explaining higher Cry1Fa enhancement by this peptide. This study shows that cadherin fragments may enhance B. thuringiensis toxicity by at least two different mechanisms or a combination thereof: (i) protection of Cry toxin from protease degradation in the insect midgut and (ii) enhancement of pore-forming ability of Cry toxin. PMID:22081566

Specific Activation of the G Protein-coupled Receptor BNGR-A21 by the Neuropeptide Corazonin from the Silkworm, Bombyx mori, Dually Couples to the Gq and Gs Signaling Cascades*

PubMed Central

Yang, Jingwen; Huang, Haishan; Yang, Huipeng; He, Xiaobai; Jiang, Xue; Shi, Ying; Alatangaole, Damirin; Shi, Liangen; Zhou, Naiming

2013-01-01

Corazonin, an undecapeptide neurohormone sharing a highly conserved amino acid sequence across Insecta, plays different physiological roles in the regulation of heart contraction rates, silk spinning rates, the induction of dark color and morphometric phase changes, and ecdysis. Corazonin receptors have been identified in Drosophila melanogaster, Manduca sexta, and Musca domestica. However, detailed information on the signaling and major physiological functions of corazonin and its receptor is largely unknown. In the current study, using both the mammalian cell line HEK293 and insect cell lines BmN and Sf21, we paired the Bombyx corazonin neuropeptide as a specific endogenous ligand for the Bombyx neuropeptide G protein-coupled receptor A21 (BNGR-A21), and we therefore designated this receptor as BmCrzR. Further characterization indicated that synthetic BmCrz demonstrated a high affinity for and activated BmCrzR, resulting in intracellular cAMP accumulation, Ca2+ mobilization, and ERK1/2 phosphorylation via the Gq- and Gs-coupled signaling pathways. The direct interaction of BmCrzR with BmCrz was confirmed by a rhodamine-labeled BmCrz peptide. Moreover, experiments with double-stranded RNA and synthetic peptide injection suggested a possible role of BmCrz/BmCrzR in the regulation of larval growth and spinning rate. Our present results provide the first in-depth information on BmCrzR-mediated signaling for further elucidation of the BmCrz/BmCrzR system in the regulation of fundamental physiological processes. PMID:23457297

The induction of tomato leucine aminopeptidase genes (LapA) after Pseudomonas syringae pv. tomato infection is primarily a wound response triggered by coronatine.

PubMed

Pautot, V; Holzer, F M; Chaufaux, J; Walling, L L

2001-02-01

Tomato plants constitutively express a neutral leucine aminopeptidase (LAP-N) and an acidic LAP (LAP-A) during floral development and in leaves in response to insect infestation, wounding, and Pseudomonas syringae pv. tomato infection. To assess the physiological roles of LAP-A, a LapA-antisense construct (35S:asLapA1) was introduced into tomato. The 35S:asLapA1 plants had greatly reduced or showed undetectable levels of LAP-A and LAP-N proteins in healthy and wounded leaves and during floral development. Despite the loss of these aminopeptidases, no global changes in protein profiles were noted. The 35S:asLapA1 plants also exhibited no significant alteration in floral development and did not impact the growth and development of Manduca sexta and P. syringae pv. tomato growth rates during compatible or incompatible infections. To investigate the mechanism underlying the strong induction of LapA upon P. syringae pv. tomato infection, LapA expression was monitored after infection with coronatine-producing and -deficient P. syringae pv. tomato strains. LapA RNA and activity were detected only with the coronatine-producing P. syringae pv. tomato strain. Coronatine treatment of excised shoots caused increases in RNAs for jasmonic acid (JA)-regulated wound-response genes (LapA and pin2) but did not influence expression of a JA-regulated pathogenesis-related protein gene (PR-1). These results indicated that coronatine mimicked the wound response but was insufficient to activate JA-regulated PR genes.

The glial investment of the adult and developing antennal lobe of Drosophila

PubMed Central

Oland, Lynne A.; Biebelhausen, John P.; Tolbert, Leslie P.

2009-01-01

In recent years, the Drosophila olfactory system, with its unparalleled opportunities for genetic dissection of development and functional organization, has been used to study the development of central olfactory neurons and the molecular basis of olfactory coding. The results of these studies have been interpreted in the absence of a detailed understanding of the steps in maturation of glial cells in the antennal lobe. Here, we present a high-resolution study of the glia associated with olfactory glomeruli in adult and developing antennal lobes. The study provides a basis for comparison of findings in Drosophila with those in the moth Manduca sexta that indicate a critical role for glia in antennal lobe development. Using flies expressing GFP under a Nervana2 driver to visualize glia for confocal microscopy, and probing at higher resolution with the electron microscope, we find that glial development in Drosophila differs markedly from that in moths: glial cell bodies remain in a rind around the glomerular neuropil; glial processes ensheathe axon bundles in the nerve layer but likely contribute little to axonal sorting; their processes insinuate between glomeruli only very late and then form only a sparse, open network around each glomerulus; and glial processes invade the synaptic neuropil. Taking our results in the context of previous studies, we conclude that glial cells in the developing Drosophila antennal lobe are unlikely to play a strong role in either axonal sorting or glomerulus stabilization and that in the adult, glial processes do not electrically isolate glomeruli from their neighbors. PMID:18537134

Spatiotemporal Coding of Individual Chemicals by the Gustatory System

PubMed Central

Reiter, Sam; Campillo Rodriguez, Chelsey; Sun, Kui

2015-01-01

Four of the five major sensory systems (vision, olfaction, somatosensation, and audition) are thought to use different but partially overlapping sets of neurons to form unique representations of vast numbers of stimuli. The only exception is gustation, which is thought to represent only small numbers of basic taste categories. However, using new methods for delivering tastant chemicals and making electrophysiological recordings from the tractable gustatory system of the moth Manduca sexta, we found chemical-specific information is as follows: (1) initially encoded in the population of gustatory receptor neurons as broadly distributed spatiotemporal patterns of activity; (2) dramatically integrated and temporally transformed as it propagates to monosynaptically connected second-order neurons; and (3) observed in tastant-specific behavior. Our results are consistent with an emerging view of the gustatory system: rather than constructing basic taste categories, it uses a spatiotemporal population code to generate unique neural representations of individual tastant chemicals. SIGNIFICANCE STATEMENT Our results provide a new view of taste processing. Using a new, relatively simple model system and a new set of techniques to deliver taste stimuli and to examine gustatory receptor neurons and their immediate followers, we found no evidence for labeled line connectivity, or basic taste categories such as sweet, salty, bitter, and sour. Rather, individual tastant chemicals are represented as patterns of spiking activity distributed across populations of receptor neurons. These representations are transformed substantially as multiple types of receptor neurons converge upon follower neurons, leading to a combinatorial coding format that uniquely, rapidly, and efficiently represents individual taste chemicals. Finally, we found that the information content of these neurons can drive tastant-specific behavior. PMID:26338341

Sugarcane giant borer transcriptome analysis and identification of genes related to digestion.

PubMed

Fonseca, Fernando Campos de Assis; Firmino, Alexandre Augusto Pereira; de Macedo, Leonardo Lima Pepino; Coelho, Roberta Ramos; de Souza Júnior, José Dijair Antonino; de Sousa Júnior, José Dijair Antonino; Silva-Junior, Orzenil Bonfim; Togawa, Roberto Coiti; Pappas, Georgios Joannis; de Góis, Luiz Avelar Brandão; da Silva, Maria Cristina Mattar; Grossi-de-Sá, Maria Fátima

2015-01-01

Sugarcane is a widely cultivated plant that serves primarily as a source of sugar and ethanol. Its annual yield can be significantly reduced by the action of several insect pests including the sugarcane giant borer (Telchin licus licus), a lepidopteran that presents a long life cycle and which efforts to control it using pesticides have been inefficient. Although its economical relevance, only a few DNA sequences are available for this species in the GenBank. Pyrosequencing technology was used to investigate the transcriptome of several developmental stages of the insect. To maximize transcript diversity, a pool of total RNA was extracted from whole body insects and used to construct a normalized cDNA database. Sequencing produced over 650,000 reads, which were de novo assembled to generate a reference library of 23,824 contigs. After quality score and annotation, 43% of the contigs had at least one BLAST hit against the NCBI non-redundant database, and 40% showed similarities with the lepidopteran Bombyx mori. In a further analysis, we conducted a comparison with Manduca sexta midgut sequences to identify transcripts of genes involved in digestion. Of these transcripts, many presented an expansion or depletion in gene number, compared to B. mori genome. From the sugarcane giant borer (SGB) transcriptome, a number of aminopeptidase N (APN) cDNAs were characterized based on homology to those reported as Cry toxin receptors. This is the first report that provides a large-scale EST database for the species. Transcriptome analysis will certainly be useful to identify novel developmental genes, to better understand the insect's biology and to guide the development of new strategies for insect-pest control.

Yeast one-hybrid screening the potential regulator of CYP6B6 overexpression of Helicoverpa armigera under 2-tridecanone stress.

PubMed

Zhao, J; Liu, X N; Li, F; Zhuang, S Z; Huang, L N; Ma, J; Gao, X W

2016-04-01

In insect, the cytochrome P450 plays a pivotal role in detoxification to toxic allelochemicals. Helicoverpa armigera can tolerate and survive in 2-tridecanone treatment owing to the CYP6B6 responsive expression, which is controlled by some regulatory DNA sequences and transcription regulators. Therefore, the 2-tridecanone responsive region and transcription regulators of the CYP6B6 are responsible for detoxification of cotton bollworm. In this study, we used yeast one-hybrid to screen two potential transcription regulators of the CYP6B6 from H. armigera that respond to the plant secondary toxicant 2-tridecanone, which were named Prey1 and Prey2, respectively. According to the NCBI database blast, Prey1 is the homology with FK506 binding protein (FKBP) of Manduca sexta and Bombyx mori that belongs to the FKBP-C superfamily, while Prey2 may be a homology of an unknown protein of Papilio or the fcaL24 protein homology of B. mori. The electrophoretic mobility shift assays revealed that the FKBP of prokaryotic expression could specifically bind to the active region of the CYP6B6 promoter. After the 6th instar larvae of H. armigera reared on 2-tridecanone artificial diet, we found there were similar patterns of CYP6B6 and FKBP expression of the cotton bollworm treated with 10 mg g-1 2-tridecanone for 48 h, which correlation coefficient was the highest (0.923). Thus, the FKBP is identified as a strong candidate for regulation of the CYP6B6 expression, when the cotton bollworm is treated with 2-tridecanone. This may lead us to a better understanding of transcriptional mechanism of CYP6B6 and provide very useful information for the pest control.

Navigating natural variation in herbivory-induced secondary metabolism in coyote tobacco populations using MS/MS structural analysis

PubMed Central

Li, Dapeng; Baldwin, Ian T.; Gaquerel, Emmanuel

2015-01-01

Natural variation can be extremely useful in unraveling the determinants of phenotypic trait evolution but has rarely been analyzed with unbiased metabolic profiling to understand how its effects are organized at the level of biochemical pathways. Native populations of Nicotiana attenuata, a wild tobacco species, have been shown to be highly genetically diverse for traits important for their interactions with insects. To resolve the chemodiversity existing in these populations, we developed a metabolomics and computational pipeline to annotate leaf metabolic responses to Manduca sexta herbivory. We selected seeds from 43 accessions of different populations from the southwestern United States—including the well-characterized Utah 30th generation inbred accession—and grew 183 plants in the glasshouse for standardized herbivory elicitation. Metabolic profiles were generated from elicited leaves of each plant using a high-throughput ultra HPLC (UHPLC)-quadrupole TOFMS (qTOFMS) method, processed to systematically infer covariation patterns among biochemically related metabolites, as well as unknown ones, and finally assembled to map natural variation. Navigating this map revealed metabolic branch-specific variations that surprisingly only partly overlapped with jasmonate accumulation polymorphisms and deviated from canonical jasmonate signaling. Fragmentation analysis via indiscriminant tandem mass spectrometry (idMS/MS) was conducted with 10 accessions that spanned a large proportion of the variance found in the complete accession dataset, and compound spectra were computationally assembled into spectral similarity networks. The biological information captured by this networking approach facilitates the mining of the mass spectral data of unknowns with high natural variation, as demonstrated by the annotation of a strongly herbivory-inducible phenolic derivative, and can guide pathway analysis. PMID:26170304

Spatiotemporal Coding of Individual Chemicals by the Gustatory System.

PubMed

Reiter, Sam; Campillo Rodriguez, Chelsey; Sun, Kui; Stopfer, Mark

2015-09-02

Four of the five major sensory systems (vision, olfaction, somatosensation, and audition) are thought to use different but partially overlapping sets of neurons to form unique representations of vast numbers of stimuli. The only exception is gustation, which is thought to represent only small numbers of basic taste categories. However, using new methods for delivering tastant chemicals and making electrophysiological recordings from the tractable gustatory system of the moth Manduca sexta, we found chemical-specific information is as follows: (1) initially encoded in the population of gustatory receptor neurons as broadly distributed spatiotemporal patterns of activity; (2) dramatically integrated and temporally transformed as it propagates to monosynaptically connected second-order neurons; and (3) observed in tastant-specific behavior. Our results are consistent with an emerging view of the gustatory system: rather than constructing basic taste categories, it uses a spatiotemporal population code to generate unique neural representations of individual tastant chemicals. Our results provide a new view of taste processing. Using a new, relatively simple model system and a new set of techniques to deliver taste stimuli and to examine gustatory receptor neurons and their immediate followers, we found no evidence for labeled line connectivity, or basic taste categories such as sweet, salty, bitter, and sour. Rather, individual tastant chemicals are represented as patterns of spiking activity distributed across populations of receptor neurons. These representations are transformed substantially as multiple types of receptor neurons converge upon follower neurons, leading to a combinatorial coding format that uniquely, rapidly, and efficiently represents individual taste chemicals. Finally, we found that the information content of these neurons can drive tastant-specific behavior. Copyright © 2015 the authors 0270-6474/15/3512309-13$15.00/0.

Identification of a Putative Mexican Strain of Serratia entomophila Pathogenic against Root-Damaging Larvae of Scarabaeidae (Coleoptera)▿ †

PubMed Central

Nuñez-Valdez, M. Eugenia; Calderón, Marco A.; Aranda, Eduardo; Hernández, Luciano; Ramírez-Gama, Rosa M.; Lina, Laura; Rodríguez-Segura, Zitlhally; Gutiérrez, María del C.; Villalobos, Francisco J.

2008-01-01

The larvae of scarab beetles, known as “white grubs” and belonging to the genera Phyllophaga and Anomala (Coleoptera: Scarabaeidae), are regarded as soil-dwelling pests in Mexico. During a survey conducted to find pathogenic bacteria with the potential to control scarab larvae, a native Serratia sp. (strain Mor4.1) was isolated from a dead third-instar Phyllophaga blanchardi larva collected from a cornfield in Tres Marías, Morelos, Mexico. Oral bioassays using healthy P. blanchardi larvae fed with the Mor4.1 isolate showed that this strain was able to cause an antifeeding effect and a significant loss of weight. Mortality was observed for P. blanchardi, P. trichodes, and P. obsoleta in a multidose experiment. The Mor4.1 isolate also caused 100% mortality 24 h after intracoelomic inoculation of the larvae of P. blanchardi, P. ravida, Anomala donovani and the lepidopteran insect Manduca sexta. Oral and injection bioassays were performed with concentrated culture broths of the Mor4.1 isolate to search for disease symptoms and mortality caused by extracellular proteins. The results have shown that Mor4.1 broths produce significant antifeeding effects and mortality. Mor4.1 broths treated with proteinase K lost the ability to cause disease symptoms and mortality, in both the oral and the injection bioassays, suggesting the involvement of toxic proteins in the disease. The Mor4.1 isolate was identified as a putative Serratia entomophila Mor4.1 strain based on numerical taxonomy and phylogenetic analyses done with the 16S rRNA gene sequence. The potential of S. entomophila Mor4.1 and its toxins to be used in an integrated pest management program is discussed. PMID:18083879

Herbivore-Triggered Electrophysiological Reactions: Candidates for Systemic Signals in Higher Plants and the Challenge of Their Identification1

PubMed Central

Zimmermann, Matthias R.; Will, Torsten; Felle, Hubert H.; Furch, Alexandra C.U.

2016-01-01

In stressed plants, electrophysiological reactions (elRs) are presumed to contribute to long-distance intercellular communication between distant plant parts. Because of the focus on abiotic stress-induced elRs in recent decades, biotic stress-triggered elRs have been widely ignored. It is likely that the challenge to identify the particular elR types (action potential [AP], variation potential, and system potential [SP]) was responsible for this course of action. Thus, this survey focused on insect larva feeding (Spodoptera littoralis and Manduca sexta) that triggers distant APs, variation potentials, and SPs in monocotyledonous and dicotyledonous plant species (Hordeum vulgare, Vicia faba, and Nicotiana tabacum). APs were detected only after feeding on the stem/culm, whereas SPs were observed systemically following damage to both stem/culm and leaves. This was attributed to the unequal vascular innervation of the plant and a selective electrophysiological connectivity of the plant tissue. However, striking variations in voltage patterns were detected for each elR type. Further analyses (also in Brassica napus and Cucurbita maxima) employing complementary electrophysiological approaches in response to different stimuli revealed various reasons for these voltage pattern variations: an intrinsic plasticity of elRs, a plant-specific signature of elRs, a specific influence of the applied (a)biotic trigger, the impact of the technical approach, and/or the experimental setup. As a consequence, voltage pattern variations, which are not irregular but rather common, need to be included in electrophysiological signaling analysis. Due to their widespread occurrence, systemic propagation, and respective triggers, elRs should be considered as candidates for long-distance communication in higher plants. PMID:26872949

Sugarcane Giant Borer Transcriptome Analysis and Identification of Genes Related to Digestion

PubMed Central

de Assis Fonseca, Fernando Campos; Firmino, Alexandre Augusto Pereira; de Macedo, Leonardo Lima Pepino; Coelho, Roberta Ramos; de Sousa Júnior, José Dijair Antonino; Silva-Junior, Orzenil Bonfim; Togawa, Roberto Coiti; Pappas, Georgios Joannis; de Góis, Luiz Avelar Brandão; da Silva, Maria Cristina Mattar; Grossi-de-Sá, Maria Fátima

2015-01-01

Sugarcane is a widely cultivated plant that serves primarily as a source of sugar and ethanol. Its annual yield can be significantly reduced by the action of several insect pests including the sugarcane giant borer (Telchin licus licus), a lepidopteran that presents a long life cycle and which efforts to control it using pesticides have been inefficient. Although its economical relevance, only a few DNA sequences are available for this species in the GenBank. Pyrosequencing technology was used to investigate the transcriptome of several developmental stages of the insect. To maximize transcript diversity, a pool of total RNA was extracted from whole body insects and used to construct a normalized cDNA database. Sequencing produced over 650,000 reads, which were de novo assembled to generate a reference library of 23,824 contigs. After quality score and annotation, 43% of the contigs had at least one BLAST hit against the NCBI non-redundant database, and 40% showed similarities with the lepidopteran Bombyx mori. In a further analysis, we conducted a comparison with Manduca sexta midgut sequences to identify transcripts of genes involved in digestion. Of these transcripts, many presented an expansion or depletion in gene number, compared to B. mori genome. From the sugarcane giant borer (SGB) transcriptome, a number of aminopeptidase N (APN) cDNAs were characterized based on homology to those reported as Cry toxin receptors. This is the first report that provides a large-scale EST database for the species. Transcriptome analysis will certainly be useful to identify novel developmental genes, to better understand the insect’s biology and to guide the development of new strategies for insect-pest control. PMID:25706301

Serine proteases SP1 and SP13 mediate the melanization response of Asian corn borer, Ostrinia furnacalis, against entomopathogenic fungus Beauveria bassiana.

PubMed

Chu, Yuan; Liu, Yang; Shen, Dongxu; Hong, Fang; Wang, Guirong; An, Chunju

2015-06-01

Exposure to entomopathogenic fungi is one approach for insect pest control. Little is known about the immune interactions between fungus and its insect host. Melanization is a prominent immune response in insects in defending against pathogens such as bacteria and fungi. Clip domain serine proteases in insect plasma have been implicated in the activation of prophenoloxidase, a key enzyme in the melanization. The relationship between host melanization and the infection by a fungus needs to be established. We report here that the injection of entomopathogenic fungus Beauveria bassiana induced both melanin synthesis and phenoloxidase activity in its host insect, the Asian corn borer, Ostrinia furnacalis (Guenée). qRT-PCR analysis showed several distinct patterns of expression of 13 clip-domain serine proteases in response to the challenge of fungi, with seven increased, two decreased, and four unchanged. Of special interest among these clip-domain serine protease genes are SP1 and SP13, the orthologs of Manduca sexta HP6 and PAP1 which are involved in the prophenoloxidase activation pathway. Recombinant O. furnacalis SP1 was found to activate proSP13 and induce the phenoloxidase activity in corn borer plasma. Additionally, SP13 was determined to directly cleave prophenoloxidase and therefore act as the prophenoloxidase activating protease. Our work thus reveals a biochemical mechanism in the melanization in corn borer associated with the challenge by B. bassiana injection. These insights could provide valuable information for better understanding the immune responses of Asian corn borer against B. bassiana. Copyright © 2015 Elsevier Inc. All rights reserved.

Natural history matters: how biological constraints shape diversified interactions in pollination networks.

PubMed

Jordano, Pedro

2016-11-01

Species-specific traits constrain the ways organisms interact in nature. Some pairwise interactions among coexisting species simply do not occur; they are impossible to observe despite the fact that partners coexist in the same place. The author discusses these 'forbidden links' of species interaction networks. Photo: a sphingid moth, Manduca sexta visiting a flower of Tocoyena formosa (Rubiaceae) in the Brazilian Cerrado; tongue and corolla tube lengths approximately 100 mm. Courtesy of Felipe Amorim. Sazatornil, F.D., Moré, M., Benitez-Vieyra, S., Cocucci, A.A., Kitching, I.J., Schlumpberger, B.O., Oliveira, P.E., Sazima, M. & Amorim, F.W. (2016) Beyond neutral and forbidden links: morphological matches and the assembly of mutualistic hawkmoth-plant networks. Journal of Animal Ecology, 85, 1586-1594. Species-specific traits and life-history characteristics constrain the ways organisms interact in nature. For example, gape-limited predators are constrained in the sizes of prey they can handle and efficiently consume. When we consider the ubiquity of such constrains, it is evident how hard it can be to be a generalist partner in ecological interactions: a free-living animal or plant cannot simply interact with every available partner it encounters. Some pairwise interactions among coexisting species simply do not occur; they are impossible to observe despite the fact that partners coexist in the same place. Sazatornil et al. () explore the nature of such constraints in the mutualisms among hawkmoths and the plants they pollinate. In this iconic interaction, used by Darwin and Wallace to vividly illustrate the power of natural selection in shaping evolutionary change, both pollinators and plants are sharply constrained in their interaction modes and outcomes. © 2016 The Author. Journal of Animal Ecology © 2016 British Ecological Society.

Hawkmoth flight stability in turbulent vortex streets.

PubMed

Ortega-Jimenez, Victor Manuel; Greeter, Jeremy S M; Mittal, Rajat; Hedrick, Tyson L

2013-12-15

Shedding of vortices is a common phenomenon in the atmosphere over a wide range of spatial and temporal scales. However, it is unclear how these vortices of varying scales affect the flight performance of flying animals. In order to examine these interactions, we trained seven hawkmoths (Manduca sexta) (wingspan ~9 cm) to fly and feed in a wind tunnel under steady flow (controls) and in the von Kármán vortex street of vertically oriented cylinders (two different cylinders with diameters of 10 and 5 cm) at speeds of 0.5, 1 and 2 m s(-1). Cylinders were placed at distances of 5, 25 and 100 cm upstream of the moths. Moths exhibited large amplitude yaw oscillations coupled with modest oscillations in roll and pitch, and slight increases in wingbeat frequency when flying in both the near (recirculating) and middle (vortex dominated) wake regions. Wingbeat amplitude did not vary among treatments, except at 1 m s(-1) for the large cylinder. Yaw and roll oscillations were synchronized with the vortex shedding frequencies in moths flying in the wake of the large cylinder at all speeds. In contrast, yaw and pitch were synchronized with the shedding frequency of small vortices at speeds ≤1 m s(-1). Oscillations in body orientation were also substantially smaller in the small cylinder treatment when compared with the large cylinder, regardless of temporal or non-dimensional spatial scale. Moths flying in steady conditions reached a higher air speed than those flying into cylinder wakes. In general, flight effects produced by the cylinder wakes were qualitatively similar among the recirculating and vortex-dominated wake regions; the magnitude of those effects, however, declined gradually with downstream distance.

Sebacina vermifera Promotes the Growth and Fitness of Nicotiana attenuata by Inhibiting Ethylene Signaling1[W

PubMed Central

Barazani, Oz; von Dahl, Caroline C.; Baldwin, Ian T.

2007-01-01

Sebacina vermifera, a growth-promoting endophytic fungus, significantly increases Nicotiana attenuata's growth but impairs both its herbivore resistance and its accumulation of the costly, jasmonic acid (JA)-regulated defense protein, trypsin proteinase inhibitor (TPI). To determine if the fungi's growth-promoting effects can be attributed to lower TPI-related defense costs, we inoculated transformed N. attenuata plants silenced in their ability to synthesize JA, JA-isoleucine, and TPI by antisense (lipoxygenase 3 [as-lox3] and Thr deaminase [as-td]) and inverted repeat (ir-tpi) expression, and found that inoculation promoted plant growth as in untransformed wild-type plants. Moreover, herbivore-elicited increases in JA and JA-isoleucine concentrations did not differ between inoculated and uninoculated wild-type plants. However, inoculation significantly reduced the morphological effect of 1-aminocyclopropane-1-carboxylic acid on wild-type seedlings in a triple response assay, suggesting that ethylene signaling was impaired. Furthermore, S. vermifera failed to promote the growth of N. attenuata plants transformed to silence ethylene production (1-aminocyclopropane-1-carboxylic acid oxidase [ir-aco]). Inoculating wild-type plants with S. vermifera decreased the ethylene burst elicited by applying Manduca sexta oral secretions to mechanical wounds. Accordingly, oral secretion-elicited transcript levels of the ethylene synthesis genes NaACS3, NaACO1, and NaACO3 in inoculated plants were significantly lower compared to these levels in uninoculated wild-type plants. Inoculation accelerated germination in wild-type seeds; however, uninoculated wild-type seeds germinated as rapidly as inoculated seeds in the presence of the ethylene scrubber KMnO4. In contrast, neither inoculation nor KMnO4 exposure influenced the germination of ir-aco seeds. We conclude that S. vermifera increases plant growth by impairing ethylene production independently of JA signaling and TPI production. PMID:17416638

Tidal distortion caused by the resonance of sexta-diurnal tides in a micromesotidal embayment

NASA Astrophysics Data System (ADS)

Song, Dehai; Yan, Yuhan; Wu, Wen; Diao, Xiliang; Ding, Yang; Bao, Xianwen

2016-10-01

Double high water and double-peak flood current were observed in Daya Bay (DYB), China, which is a shallow, mixed, mainly semidiurnal-tide dominated bay with a micro to mesotidal range. Harmonic analysis reveals that the quarter and especially the sexta-diurnal constituents are getting much stronger as tides propagating into the bay. The astronomical tides-induced tidal asymmetry is yet dominant at the bay entrance but overtaken by the sexta-diurnal tides at the end of the bay. Both the M4 and M6 tide meet the requirement proposed in previous studies but still unable to produce a double high water alone. Therefore, the conditions to produce a double high water between a fundamental tide and its higher harmonics need to be revisited. Analytical solutions were obtained in this paper, which fit the numerical solutions very well. Modeling result indicates M6 alone with M2 can produce the double high water in DYB but limited in some regions, while the combination of M2, M4, and M6 tides would enhance the capability. The amplification of sexta-diurnal tides in DYB is dominated by resonance and followed by shoaling effect. Bottom friction damped M6 a lot and largely confined its amplification. However, the quadratic friction and other nonlinear processes are just responsible for about 10% of the total M6 increase.

Parental Legacy in Insects: Variation of Transgenerational Immune Priming during Offspring Development

PubMed Central

Trauer, Ute; Hilker, Monika

2013-01-01

In insects, a parental immune challenge can prepare and enhance offspring immune activity. Previous studies of such transgenerational immune priming (TGIP) mainly focused on a single offspring life stage. However, different developmental stages may be exposed to different risks and show different susceptibility to parental immune priming. Here we addressed the question (i) whether TGIP effects on the immunity of Manduca sexta offspring vary among the different developmental offspring stages. We differentiated between unchallenged and immunochallenged offspring; for the latter type of offspring, we further investigated (ii) whether TGIP has an impact on the time that enhanced immune levels persist after offspring immune challenge. Finally, we determined (iii) whether TGIP effects on offspring performance depend on the offspring stage. Our results show that TGIP effects on phenoloxidase (PO) activity, but not on antibacterial activity, vary among unchallenged offspring stages. In contrast, TGIP effects on PO and antibacterial activity did not vary among immunochallenged offspring stages. The persistence of enhanced immune levels in immunochallenged offspring was dependent on the parental immune state. Antibacterial (but not PO) activity in offspring of immunochallenged parents decreased over five days after pupal immune challenge, whereas no significant change over time was detectable in offspring of control parents. Finally, TGIP effects on the developmental time of unchallenged offspring varied among stages; young larvae of immunochallenged parents developed faster and gained more weight than larvae of control parents. However, offspring females of immunochallenged parents laid fewer eggs than females derived from control parents. These findings suggest that the benefits which the offspring gains from TGIP during juvenile development are paid by the adults with reduced reproductive power. Our study shows that TGIP effects vary among offspring stages and depend on the type of immunity (PO or antibacterial activity) as well as the time past offspring immune challenge. PMID:23700423

Identification of candidate infection genes from the model entomopathogenic nematode Heterorhabditis bacteriophora.

PubMed

Vadnal, Jonathan; Ratnappan, Ramesh; Keaney, Melissa; Kenney, Eric; Eleftherianos, Ioannis; O'Halloran, Damien; Hawdon, John M

2017-01-03

Despite important progress in the field of innate immunity, our understanding of host immune responses to parasitic nematode infections lags behind that of responses to microbes. A limiting factor has been the obligate requirement for a vertebrate host which has hindered investigation of the parasitic nematode infective process. The nematode parasite Heterorhabditis bacteriophora offers great potential as a model to genetically dissect the process of infection. With its mutualistic Photorhabdus luminescens bacteria, H. bacteriophora invades multiple species of insects, which it kills and exploits as a food source for the development of several nematode generations. The ability to culture the life cycle of H. bacteriophora on plates growing the bacterial symbiont makes it a very exciting model of parasitic infection that can be used to unlock the molecular events occurring during infection of a host that are inaccessible using vertebrate hosts. To profile the transcriptional response of an infective nematode during the early stage of infection, we performed next generation RNA sequencing on H. bacteriophora IJs incubated in Manduca sexta hemolymph plasma for 9 h. A subset of up-regulated and down-regulated genes were validated using qRT-PCR. Comparative analysis of the transcriptome with untreated controls found a number of differentially expressed genes (DEGs) which cover a number of different functional categories. A subset of DEGs is conserved across Clade V parasitic nematodes revealing an array of candidate parasitic genes. Our analysis reveals transcriptional changes in the regulation of a large number of genes, most of which have not been shown previously to play a role in the process of infection. A significant proportion of these genes are unique to parasitic nematodes, suggesting the identification of a group of parasitism factors within nematodes. Future studies using these candidates may provide functional insight into the process of nematode parasitism and also the molecular evolution of parasitism within nematodes.

Monoclonal Antibody Analysis and Insecticidal Spectrum of Three Types of Lepidopteran-Specific Insecticidal Crystal Proteins of Bacillus thuringiensis

PubMed Central

Höfte, Herman; Van Rie, Jeroen; Jansens, Stefan; Van Houtven, Annemie; Vanderbruggen, Hilde; Vaeck, Mark

1988-01-01

We have investigated the protein composition and the insecticidal spectrum of crystals of 29 Bacillus thuringiensis strains active against lepidopteran larvae. All crystals contained proteins of 130 to 140 kilodaltons (kDa) which could be grouped into three types by the molecular weight of the protoxin and the trypsin-activated core fragment. Proteins of the three types showed a characteristic insecticidal spectrum when tested against five lepidopteran species. Type A crystal proteins were protoxins of 130 or 133 kDa, which were processed into 60-kDa toxins by trypsin. Several genes encoding crystal proteins of this type have been cloned and sequenced earlier. They are highly conserved in the N-terminal half of the toxic fragment and were previously classified in three subtypes (the 4.5-, 5.3-, and 6.6-kilobase subtypes) based on the restriction map of their genes. The present study shows that different proteins of these three subtypes were equally toxic against Manduca sexta and Pieris brassicae and had no detectable activity against Spodoptera littoralis. However, the 4.5-, 5.3-, and 6.6-kilobase subtypes differed in their toxicity against Heliothis virescens and Mamestra brassicae. Type B crystal proteins consisted of 140-kDa protoxins with a 55-kDa tryptic core fragment. These were only active against one of the five insect species tested (P. brassicae). The protoxin and the trypsin-activated toxin of type C were 135- and 63-kDa proteins, respectively. Proteins of this type were associated with high toxicity against S. littoralis and M. brassicae. A panel of 35 monoclonal antibodies was used to compare the structural characteristics of crystal proteins of the three different types and subtypes. Each type of protein could be associated with a typical epitope structure, indicating an unambiguous correlation between antigenic structure and insect specificity. Images PMID:16347711

Genome-wide identification and expression profiling of serine proteases and homologs in the diamondback moth, Plutella xylostella (L.).

PubMed

Lin, Hailan; Xia, Xiaofeng; Yu, Liying; Vasseur, Liette; Gurr, Geoff M; Yao, Fengluan; Yang, Guang; You, Minsheng

2015-12-10

Serine proteases (SPs) are crucial proteolytic enzymes responsible for digestion and other processes including signal transduction and immune responses in insects. Serine protease homologs (SPHs) lack catalytic activity but are involved in innate immunity. This study presents a genome-wide investigation of SPs and SPHs in the diamondback moth, Plutella xylostella (L.), a globally-distributed destructive pest of cruciferous crops. A total of 120 putative SPs and 101 putative SPHs were identified in the P. xylostella genome by bioinformatics analysis. Based on the features of trypsin, 38 SPs were putatively designated as trypsin genes. The distribution, transcription orientation, exon-intron structure and sequence alignments suggested that the majority of trypsin genes evolved from tandem duplications. Among the 221 SP/SPH genes, ten SP and three SPH genes with one or more clip domains were predicted and designated as PxCLIPs. Phylogenetic analysis of CLIPs in P. xylostella, two other Lepidoptera species (Bombyx mori and Manduca sexta), and two more distantly related insects (Drosophila melanogaster and Apis mellifera) showed that seven of the 13 PxCLIPs were clustered with homologs of the Lepidoptera rather than other species. Expression profiling of the P. xylostella SP and SPH genes in different developmental stages and tissues showed diverse expression patterns, suggesting high functional diversity with roles in digestion and development. This is the first genome-wide investigation on the SP and SPH genes in P. xylostella. The characterized features and profiled expression patterns of the P. xylostella SPs and SPHs suggest their involvement in digestion, development and immunity of this species. Our findings provide a foundation for further research on the functions of this gene family in P. xylostella, and a better understanding of its capacity to rapidly adapt to a wide range of environmental variables including host plants and insecticides.

Characterization and expression profiling of serine protease inhibitors in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae).

PubMed

Lin, Hailan; Lin, Xijian; Zhu, Jiwei; Yu, Xiao-Qiang; Xia, Xiaofeng; Yao, Fengluan; Yang, Guang; You, Minsheng

2017-02-14

Serine protease inhibitors (SPIs) have been found in all living organisms and play significant roles in digestion, development and innate immunity. In this study, we present a genome-wide identification and expression profiling of SPI genes in the diamondback moth, Plutella xylostella (L.), a major pest of cruciferous crops with global distribution and broad resistance to different types of insecticides. A total of 61 potential SPI genes were identified in the P. xylostella genome, and these SPIs were classified into serpins, canonical inhibitors, and alpha-2-macroglobulins based on their modes of action. Sequence alignments showed that amino acid residues in the hinge region of known inhibitory serpins from other insect species were conserved in most P. xylostella serpins, suggesting that these P. xylostella serpins may be functionally active. Phylogenetic analysis confirmed that P. xylostella inhibitory serpins were clustered with known inhibitory serpins from six other insect species. More interestingly, nine serpins were highly similar to the orthologues in Manduca sexta which have been demonstrated to participate in regulating the prophenoloxidase activation cascade, an important innate immune response in insects. Of the 61 P.xylostella SPI genes, 33 were canonical SPIs containing seven types of inhibitor domains, including Kunitz, Kazal, TIL, amfpi, Antistasin, WAP and Pacifastin. Moreover, some SPIs contained additional non-inhibitor domains, including spondin_N, reeler, and other modules, which may be involved in protein-protein interactions. Gene expression profiling showed gene-differential, stage- and sex-specific expression patterns of SPIs, suggesting that SPIs may be involved in multiple physiological processes in P. xylostella. This is the most comprehensive investigation so far on SPI genes in P. xylostella. The characterized features and expression patterns of P. xylostella SPIs indicate that the SPI family genes may be involved in innate immunity of this species. Our findings provide valuable information for uncovering further biological roles of SPI genes in P. xylostella.

Molecular evolution of the odorant and gustatory receptor genes in lepidopteran insects: implications for their adaptation and speciation.

PubMed

Engsontia, Patamarerk; Sangket, Unitsa; Chotigeat, Wilaiwan; Satasook, Chutamas

2014-08-01

Lepidoptera (comprised of butterflies and moths) is one of the largest groups of insects, including more than 160,000 described species. Chemoreception plays important roles in the adaptation of these species to a wide range of niches, e.g., plant hosts, egg-laying sites, and mates. This study investigated the molecular evolution of the lepidopteran odorant (Or) and gustatory receptor (Gr) genes using recently identified genes from Bombyx mori, Danaus plexippus, Heliconius melpomene, Plutella xylostella, Heliothis virescens, Manduca sexta, Cydia pomonella, and Spodoptera littoralis. A limited number of cases of large lineage-specific gene expansion are observed (except in the P. xylostella lineage), possibly due to selection against tandem gene duplication. There has been strong purifying selection during the evolution of both lepidopteran odorant and gustatory genes, as shown by the low ω values estimated through CodeML analysis, ranging from 0.0093 to 0.3926. However, purifying selection has been relaxed on some amino acid sites in these receptors, leading to sequence divergence, which is a precursor of positive selection on these sequences. Signatures of positive selection were detected only in a few loci from the lineage-specific analysis. Estimation of gene gains and losses suggests that the common ancestor of the Lepidoptera had fewer Or genes compared to extant species and an even more reduced number of Gr genes, particularly within the bitter receptor clade. Multiple gene gains and a few gene losses occurred during the evolution of Lepidoptera. Gene family expansion may be associated with the adaptation of lepidopteran species to plant hosts, especially after angiosperm radiation. Phylogenetic analysis of the moth sex pheromone receptor genes suggested that chromosomal translocations have occurred several times. New sex pheromone receptors have arisen through tandem gene duplication. Positive selection was detected at some amino acid sites predicted to be in the extracellular and transmembrane regions of the newly duplicated genes, which might be associated with the evolution of the new pheromone receptors.

Toxicity and mode of action of insecticidal Cry1A proteins from Bacillus thuringiensis in an insect cell line, CF-1.

PubMed

Portugal, Leivi; Gringorten, J Lawrence; Caputo, Guido F; Soberón, Mario; Muñoz-Garay, Carlos; Bravo, Alejandra

2014-03-01

Bacillus thuringiensis Cry toxins are insecticidal proteins used to control insect pests. The interaction of Cry toxins with the midgut of susceptible insects is a dynamic process involving activation of the toxin, binding to midgut receptors in the apical epithelium and conformational changes in the toxin molecule, leading to pore formation and cell lysis. An understanding of the molecular events underlying toxin mode of action is essential for the continued use of Cry toxins. In this work, we examined the mechanism of action of Cry1A toxins in the lepidopteran cell line CF-1, using native Cry1Ab and mutant forms of this protein that interfer with different steps in the mechanism of action, specifically, receptor binding, oligomerization or pore formation. These mutants lost activity against both Manduca sexta larvae and CF-1 cells. We also analyzed a mutation created in domain I of Cry1Ab, in which helix α-1 and part of helix α-2 were deleted (Cry1AbMod). Cry1AbMod is able to oligomerize in the absence of toxin receptors, and although it shows reduced activity against some susceptible insects, it kills insect pests that have developed resistance to native Cry1Ab. Cry1AbMod showed enhanced toxicity to CF-1, suggesting that oligomerization of native Cry1Ab may be a limiting step in its activity against CF-1 cells. The toxicity of Cry1Ac and Cry1AcMod were also analyzed. Our results suggest that some of the steps in the mode of action of Cry1A toxins are conserved in vivo in insect midgut cells and in vitro in an established cell line, CF-1. Copyright © 2013 Elsevier Inc. All rights reserved.

Segmental duplications: evolution and impact among the current Lepidoptera genomes.

PubMed

Zhao, Qian; Ma, Dongna; Vasseur, Liette; You, Minsheng

2017-07-06

Structural variation among genomes is now viewed to be as important as single nucleoid polymorphisms in influencing the phenotype and evolution of a species. Segmental duplication (SD) is defined as segments of DNA with homologous sequence. Here, we performed a systematic analysis of segmental duplications (SDs) among five lepidopteran reference genomes (Plutella xylostella, Danaus plexippus, Bombyx mori, Manduca sexta and Heliconius melpomene) to understand their potential impact on the evolution of these species. We find that the SDs content differed substantially among species, ranging from 1.2% of the genome in B. mori to 15.2% in H. melpomene. Most SDs formed very high identity (similarity higher than 90%) blocks but had very few large blocks. Comparative analysis showed that most of the SDs arose after the divergence of each linage and we found that P. xylostella and H. melpomene showed more duplications than other species, suggesting they might be able to tolerate extensive levels of variation in their genomes. Conserved ancestral and species specific SD events were assessed, revealing multiple examples of the gain, loss or maintenance of SDs over time. SDs content analysis showed that most of the genes embedded in SDs regions belonged to species-specific SDs ("Unique" SDs). Functional analysis of these genes suggested their potential roles in the lineage-specific evolution. SDs and flanking regions often contained transposable elements (TEs) and this association suggested some involvement in SDs formation. Further studies on comparison of gene expression level between SDs and non-SDs showed that the expression level of genes embedded in SDs was significantly lower, suggesting that structure changes in the genomes are involved in gene expression differences in species. The results showed that most of the SDs were "unique SDs", which originated after species formation. Functional analysis suggested that SDs might play different roles in different species. Our results provide a valuable resource beyond the genetic mutation to explore the genome structure for future Lepidoptera research.

Remodeling of the abdominal epithelial monolayer during the larva-pupa-adult transformation of Manduca.

PubMed

Nardi, James B; Bee, Charles Mark; Wallace, Catherine Lee

2018-06-01

During metamorphosis of insect epithelial monolayers, cells die, divide, and rearrange. In Drosophila undifferentiated diploid cells destined to form the adult cuticle of each abdominal segment segregate early in development from the surrounding polyploid larval epithelial cells of that segment as eight groups of diploid histoblast cells. The larval polyploid cells are programmed to die and be replaced by divisions and rearrangements of histoblast cells. By contrast, abdominal epithelial cells of Manduca larvae form a monolayer of cells representing different ploidy levels with no definitive segregation of diploid cells destined to form adult structures. These epithelial cells of mixed ploidy levels produce a thick smooth larval cuticle with sparsely distributed sensory bristles. Adult descendants of this larval monolayer produce a thinner cuticle with densely packed scale cells. The transition between these differentiated states of Manduca involves divisions of cells, changes in ploidy levels, and sorting of certain polyploid cells into circular rosette patches to minimize contacts of these polyploid cells with surrounding cells of equal or smaller size. Cells within the rosettes and some surrounding cells are destined to die and be replaced by remaining epithelial cells of uniform size and ploidy at pupa-adult apolysis. Copyright © 2018 Elsevier Inc. All rights reserved.

Bacillus thuringiensis subsp. kurstaki HD1 as a factory to synthesize alkali-labile ChiA74∆sp chitinase inclusions, Cry crystals and spores for applied use.

PubMed

Barboza-Corona, José Eleazar; Delgadillo-Ángeles, Jorge Luis; Castañeda-Ramírez, José Cristóbal; Barboza-Pérez, Uriel Eleazar; Casados-Vázquez, Luz Edith; Bideshi, Dennis K; del Rincón-Castro, Ma Cristina

2014-01-24

The endochitinase ChiA74 is a soluble secreted enzyme produced by Bacillus thuringiensis that synergizes the entomotoxigenecity of Cry proteins that accumulate as intracellular crystalline inclusion during sporulation. The purpose of this study was to produce alkaline-soluble ChiA74∆sp inclusions in B. thuringiensis, and to determine its effect on Cry crystal production, sporulation and toxicity to an important agronomical insect, Manduca sexta. To this end we deleted the secretion signal peptide-coding sequence of chiA74 (i.e. chiA74∆sp) and expressed it under its native promoter (pEHchiA74∆sp) or strong chimeric sporulation-dependent cytA-p/STAB-SD promoter (pEBchiA74∆sp) in Escherichia coli, acrystalliferous B. thuringiensis (4Q7) and B. thuringiensis HD1. Based on mRNA analyses, up to ~9-fold increase in expression of chiA74∆sp was observed using the cytA-p/STAB-SD promoter. ChiA74∆sp (~70 kDa) formed intracellular inclusions that frequently accumulated at the poles of cells. ChiA74∆sp inclusions were dissolved in alkali and reducing conditions, similar to Cry crystals, and retained its activity in a wide range of pH (5 to 9), but showed a drastic reduction (~70%) at pH 10. Chitinase activity of E. coli-pEHchiA74∆sp was ~150 mU/mL, and in E. coli-pEBchiA74∆sp, 250 mU/mL. 4Q7-pEBchiA74∆sp and 4Q7-pEHchiA74∆sp had activities of ~127 mU/mL and ~41 mU/mL, respectively. The endochitinase activity in HD1-pEBchiA74∆sp increased 42x when compared to parental HD1 strain. HD1-pEBchiA74∆sp and HD1 harbored typical bipyramidal Cry inclusions, but crystals in the recombinant were ~30% smaller. Additionally, a 3x increase in the number of viable spores was observed in cultures of the recombinant strain when compared to HD1. Bioassays against first instar larvae of M. sexta with spore-crystals of HD1 or spore-crystal-ChiA74∆sp inclusions of HD1-pEBchiA74∆sp showed LC₅₀s of 67.30 ng/cm² and 41.45 ng/cm², respectively. Alkali-labile ChiA74∆sp inclusion bodies can be synthesized in E. coli and B. thuringiensis strains. We demonstrated for the first time the applied utility of synthesis of ChiA74∆sp inclusions, Cry crystals and spores in the same sporangium of HD1, a strain used successfully worldwide to control economically significant lepidopteran pests of agriculture. Our findings will allow to us develop strategies to modify expression of ChiA74∆sp while maximizing Cry crystal synthesis in commercial strains of B. thuringiensis.

Characterization and expression profiling of ATP-binding cassette transporter genes in the diamondback moth, Plutella xylostella (L.).

PubMed

Qi, Weiping; Ma, Xiaoli; He, Weiyi; Chen, Wei; Zou, Mingmin; Gurr, Geoff M; Vasseur, Liette; You, Minsheng

2016-09-27

ATP-binding cassette (ABC) transporters are one of the major transmembrane protein families found in all organisms and play important roles in transporting a variety of compounds across intra and extra cellular membranes. In some species, ABC transporters may be involved in the detoxification of substances such as insecticides. The diamondback moth, Plutella xylostella (L.), a destructive pest of cruciferous crops worldwide, is an important species to study as it is resistant to many types of insecticides as well as biological control Bacillus thuringiensis toxins. A total of 82 ABC genes were identified from our published P. xylostella genome, and grouped into eight subfamilies (ABCA-H) based on phylogenetic analysis. Genes of subfamilies ABCA, ABCC and ABCH were found to be expanded in P. xylostella compared with those in Bombyx mori, Manduca sexta, Heliconius melpomene, Danaus plexippus, Drosophila melanogaster, Tetranychus urticae and Homo sapiens. Phylogenetic analysis indicated that many of the ABC transporters in P. xylostella are orthologous to the well-studied ABC transporter genes in the seven other species. Transcriptome- and qRT-PCR-based analysis elucidated physiological effects of ABC gene expressions of P. xylostella which were developmental stage- and tissue-specific as well as being affected by whether or not the insects were from an insecticide-resistant strain. Two ABCC and one ABCA genes were preferentially expressed in midgut of the 4th-instar larvae of a susceptible strain (Fuzhou-S) suggesting their potential roles in metabolizing plant defensive chemicals. Most of the highly expressed genes in insecticide-resistant strains were also predominantly expressed in the tissues of Malpighian tubules and midgut. This is the most comprehensive study on identification, characterization and expression profiling of ABC transporter genes in P. xylostella to date. The diversified features and expression patterns of this gene family may be associated with the evolutionary capacity of this species to develop resistance to a wide range of insecticides and biological toxins. Our findings provide a solid foundation for future functional studies on specific ABC transporter genes in P. xylostella, and for further understanding of their physiological roles and regulatory pathways in insecticide resistance.

The Yersinia pseudotuberculosis and Yersinia pestis toxin complex is active against cultured mammalian cells.

PubMed

Hares, Michelle C; Hinchliffe, Stewart J; Strong, Philippa C R; Eleftherianos, Ioannis; Dowling, Andrea J; ffrench-Constant, Richard H; Waterfield, Nick

2008-11-01

The toxin complex (Tc) genes were first identified in the insect pathogen Photorhabdus luminescens and encode approximately 1 MDa protein complexes which are toxic to insect pests. Subsequent genome sequencing projects have revealed the presence of tc orthologues in a range of bacterial pathogens known to be associated with insects. Interestingly, members of the mammalian-pathogenic yersiniae have also been shown to encode Tc orthologues. Studies in Yersinia enterocolitica have shown that divergent tc loci either encode insect-active toxins or play a role in colonization of the gut in gastroenteritis models of rats. So far little is known about the activity of the Tc proteins in the other mammalian-pathogenic yersiniae. Here we present work to suggest that Tc proteins in Yersinia pseudotuberculosis and Yersinia pestis are not insecticidal toxins but have evolved for mammalian pathogenicity. We show that Tc is secreted by Y. pseudotuberculosis strain IP32953 during growth in media at 28 degrees C and 37 degrees C. We also demonstrate that oral toxicity of strain IP32953 to Manduca sexta larvae is not due to Tc expression and that lysates of Escherichia coli BL21 expressing the Yersinia Tc proteins are not toxic to Sf9 insect cells but are toxic to cultured mammalian cell lines. Cell lysates of E. coli BL21 expressing the Y. pseudotuberculosis Tc proteins caused actin ruffles, vacuoles and multi-nucleation in cultured human gut cells (Caco-2); similar morphology was observed after application of a lysate of E. coli BL21 expressing the Y. pestis Tc proteins to mouse fibroblast NIH3T3 cells, but not Caco-2 cells. Finally, transient expression of the individual Tc proteins in Caco-2 and NIH3T3 cell lines reproduced the actin and nuclear rearrangement observed with the topical applications. Together these results add weight to the growing hypothesis that the Tc proteins in Y. pseudotuberculosis and Y. pestis have been adapted for mammalian pathogenicity. We further conclude that Tc proteins from Y. pseudotuberculosis and Y. pestis display differential mammalian cell specificity in their toxicity.

Contrasting patterns of evolutionary constraint and novelty revealed by comparative sperm proteomic analysis in Lepidoptera.

PubMed

Whittington, Emma; Forsythe, Desiree; Borziak, Kirill; Karr, Timothy L; Walters, James R; Dorus, Steve

2017-12-02

Rapid evolution is a hallmark of reproductive genetic systems and arises through the combined processes of sequence divergence, gene gain and loss, and changes in gene and protein expression. While studies aiming to disentangle the molecular ramifications of these processes are progressing, we still know little about the genetic basis of evolutionary transitions in reproductive systems. Here we conduct the first comparative analysis of sperm proteomes in Lepidoptera, a group that exhibits dichotomous spermatogenesis, in which males produce a functional fertilization-competent sperm (eupyrene) and an incompetent sperm morph lacking nuclear DNA (apyrene). Through the integrated application of evolutionary proteomics and genomics, we characterize the genomic patterns potentially associated with the origination and evolution of this unique spermatogenic process and assess the importance of genetic novelty in Lepidopteran sperm biology. Comparison of the newly characterized Monarch butterfly (Danaus plexippus) sperm proteome to those of the Carolina sphinx moth (Manduca sexta) and the fruit fly (Drosophila melanogaster) demonstrated conservation at the level of protein abundance and post-translational modification within Lepidoptera. In contrast, comparative genomic analyses across insects reveals significant divergence at two levels that differentiate the genetic architecture of sperm in Lepidoptera from other insects. First, a significant reduction in orthology among Monarch sperm genes relative to the remainder of the genome in non-Lepidopteran insect species was observed. Second, a substantial number of sperm proteins were found to be specific to Lepidoptera, in that they lack detectable homology to the genomes of more distantly related insects. Lastly, the functional importance of Lepidoptera specific sperm proteins is broadly supported by their increased abundance relative to proteins conserved across insects. Our results identify a burst of genetic novelty amongst sperm proteins that may be associated with the origin of heteromorphic spermatogenesis in ancestral Lepidoptera and/or the subsequent evolution of this system. This pattern of genomic diversification is distinct from the remainder of the genome and thus suggests that this transition has had a marked impact on lepidopteran genome evolution. The identification of abundant sperm proteins unique to Lepidoptera, including proteins distinct between specific lineages, will accelerate future functional studies aiming to understand the developmental origin of dichotomous spermatogenesis and the functional diversification of the fertilization incompetent apyrene sperm morph.

A new lipid carrier protein in the cattle tick Rhipicephalus microplus.

PubMed

Kluck, George E G; Silva Cardoso, Lívia; De Cicco, Nuccia N T; Lima, Michele S; Folly, Evelize; Atella, Georgia C

2018-05-01

Tick infestation in cattle reflects the main cause of economic loss to cattle producers. This is due to several reasons but mainly to their ability to feed on blood and generate a huge amount of eggs. Lipid transport in arthropods is achieved by highly specialized hemolymphatic lipoproteins, which resemble those described in vertebrate blood. Such lipoproteins continuously deliver lipids through the blood to growing eggs. The injection of radioactive [ 3 H] palmitic acid into tick hemocoel showed that the gut, ovary, fat body and Gene's organ were the main organs of incorporation of this labeled fatty acid. The rate of [ 3 H] palmitic acid incorporation by the organs was high up to 30 min after injection. The [ 3 H] palmitic acid incorporated by these organs was later found in phospholipids and neutral lipids. Here, we describe the purification and characterization of a key player of lipid dynamics in tick hemolymph. The Rhipicephalus microplus lipid-apolipoprotein complex (RmLCP) is a new high-density lipoprotein (1.18 g/mL), which accounts for over 90% of [ 3 H] palmitic acid present in the hemolymph. It has a native molecular weight of 420 kDa and is composed of one subunit of 122 kDa. Protein identification analysis of RmLPC subunit showed two better hits: vitellogenin 2 (23% protein coverage) and vitellogenin 5 (29% protein coverage), respectively and similarities with hemolymphatic apolipoproteins of arachnids such as the tick Ixodes scapularis (80%), the mite Galendromus occidentalis (44%) and the spider Parasteatoda tepidariorum (43%) and also for the insects Locusta migratoria (45%), Drosophila melanogaster (42%) and Manduca sexta (47%) to vitellogenin 2 and tick Ixodes scapularis (83%), the crab Limulus polyphemus (55%) and the oyster Crassostrea gigas (55%) to vitellogenin 5. Furthermore, it shows a distinct lipid composition from most arthropod lipoproteins, being composed of 40% free cholesterol, 27% phospholipids, 20% triacylglycerol and 15% hydrocarbons. In addition to binding most hemolymphatic fatty acids, this lipoprotein also binds and transports free cholesterol. In conclusion, the present study provides insight into the macromolecules involved in arachnid metabolism, which have significant potential for future use for the biological control of ticks. Copyright © 2018 Elsevier GmbH. All rights reserved.

Characterisation and tissue distribution of the PISCF allatostatin receptor in the red flour beetle, Tribolium castaneum.

PubMed

Audsley, Neil; Vandersmissen, Hans Peter; Weaver, Robert; Dani, Paulina; Matthews, June; Down, Rachel; Vuerinckx, Kristel; Kim, Young-Joon; Vanden Broeck, Jozef

2013-01-01

The insect PISCF/allatostatins (ASTs) are pleiotropic peptides that are involved in the regulation of juvenile hormone biosynthesis, are myoinhibitory on the gut and the heart, and suppress feeding in various insects, but their roles in beetles are poorly understood. To provide further insight into the significance of PISCF/ASTs in beetles, the PISCF/AST receptor from Tribolium castaneum has been characterised and its tissue distribution determined. The biological activity of the T. castaneum PISCF/AST (Trica-AS) was also investigated. The Trica-AS receptor shows high sequence homology to other insect PISCF/AST receptors, which are related to the mammalian somatostatin/opioid receptors, a family of G protein-coupled receptors. The Trica-AS receptor was activated in a dose-dependent manner by both Trica-AS and T. castaneum allatostatin double C (Trica-ASTCC) as well as Manduca sexta-allatostatin (Manse-AS). Other allatoregulatory peptides (a FLG/AST, a MIP/AST and an allatotropin) and somatostatin(14) were inactive on this receptor. Receptor transcript levels in tissues, determined by qRT-PCR, were highest in the head and the gut, with variable amounts in the fat body and reproductive organs. There were measurable differences in receptor levels of the head, fat body and reproductive organs between males and females. There was also a widespread distribution of Trica-AS in various tissues of T. castaneum. The Trica-AS peptide precursor was most abundant in the head and there was a significant difference between levels in the heads and reproductive organs of males and females. Whole mount immunocytochemistry localised Trica-AS in the median and lateral neurosecretory cells of the brain, in the corpus cardiacum and throughout the ventral nerve cord. The peptide was also present in midgut neurosecretory cells, but no immunostaining was detected in the reproductive organs or Malpighian tubules. The widespread distribution of both Trica-AS and its receptor suggest this peptide may have multiple roles in beetles. However, Trica-AS had no effect on the spontaneous contractions of the gut or ovaries of T. castaneum but this peptide did stimulate the release of proteases from the anterior midgut of another beetle, Tenebrio molitor. The activation of the Trica-AS receptor by Trica-ASTCC implies a physiological role for this peptide in beetles, which remains to be identified. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Antennal transcriptome analysis and comparison of olfactory genes in two sympatric defoliators, Dendrolimus houi and Dendrolimus kikuchii (Lepidoptera: Lasiocampidae).

PubMed

Zhang, Sufang; Zhang, Zhen; Wang, Hongbin; Kong, Xiangbo

2014-09-01

The Yunnan pine and Simao pine caterpillar moths, Dendrolimus houi Lajonquière and Dendrolimus kikuchii Matsumura (Lepidoptera: Lasiocampidae), are two closely related and sympatric pests of coniferous forests in southwestern China, and olfactory communication systems of these two insects have received considerable attention because of their economic importance. However, there is little information on the molecular aspect of odor detection about these insects. Furthermore, although lepidopteran species have been widely used in studies of insect olfaction, few work made comparison between sister moths on the olfactory recognition mechanisms. In this study, next-generation sequencing of the antennal transcriptome of these two moths were performed to identify the major olfactory genes. After comparing the antennal transcriptome of these two moths, we found that they exhibit highly similar transcripts-associated GO terms. Chemosensory gene families were further analyzed in both species. We identified 23 putative odorant binding proteins (OBP), 17 chemosensory proteins (CSP), two sensory neuron membrane proteins (SNMP), 33 odorant receptors (OR), and 10 ionotropic receptors (IR) in D. houi; and 27 putative OBPs, 17 CSPs, two SNMPs, 33 ORs, and nine IRs in D. kikuchii. All these transcripts were full-length or almost full-length. The predicted protein sequences were compared with orthologs in other species of Lepidoptera and model insects, including Bombyx mori, Manduca sexta, Heliothis virescens, Danaus plexippus, Sesamia inferens, Cydia pomonella, and Drosophila melanogaster. The sequence homologies of the orthologous genes in D. houi and D. kikuchii are very high. Furthermore, the olfactory genes were classed according to their expression level, and the highly expressed genes are our target for further function investigation. Interestingly, many highly expressed genes are ortholog gene of D. houi and D. kikuchii. We also found that the Classic OBPs were further separated into three groups according to their motifs, which will help future functional researches. Surprisingly, no pheromone receptor was identified in the two Dendrolimus species, which may indicate a special pheromone identification mechanism in Dendrolimus. Our work allows for further functional studies of pheromones and host volatile recognition genes, and give novel candidate targets for pest management. Copyright © 2014 Elsevier Ltd. All rights reserved.

The role of reduced oxygen in the developmental physiology of growth and metamorphosis initiation in Drosophila

USDA-ARS?s Scientific Manuscript database

Rearing oxygen level is known to affect final body size in a variety of insects, but the physiological mechanisms by which oxygen affects size are incompletely understood. In Manduca and Drosophila, the larval size at which metamorphosis is initiated largely determines adult size, and metamorphosis ...

Publications on Aerospace Medicine of Dr. H. J. /Von Beckh (1941 - 1987)

DTIC Science & Technology

1986-12-31

Ciclo de Conferencias sobre Medicina A~ro-espacial coincidiendo con el XVII. Congreso Internacional Astronautico. Inspeccion General de Sanidad del...Astronautica (Medical Problems of Astronautics). Sexta Con- 14 NADC 86147 -60 ferencia del Ciclo 1952 de la Sociedad Argentina Interplanetaria...del ciclo 1953 de ia Sociedad Argentina Interplanetaria. Auditorium of the Department of Physiology, Medical School. University of Buenos Aires. 20 Aug

Analysis of chitin-binding proteins from Manduca sexta provides new insights into evolution of peritrophin A-type chitin-binding domains in insects.

PubMed

Tetreau, Guillaume; Dittmer, Neal T; Cao, Xiaolong; Agrawal, Sinu; Chen, Yun-Ru; Muthukrishnan, Subbaratnam; Haobo, Jiang; Blissard, Gary W; Kanost, Michael R; Wang, Ping

2015-07-01

In insects, chitin is a major structural component of the cuticle and the peritrophic membrane (PM). In nature, chitin is always associated with proteins among which chitin-binding proteins (CBPs) are the most important for forming, maintaining and regulating the functions of these extracellular structures. In this study, a genome-wide search for genes encoding proteins with ChtBD2-type (peritrophin A-type) chitin-binding domains (CBDs) was conducted. A total of 53 genes encoding 56 CBPs were identified, including 15 CPAP1s (cuticular proteins analogous to peritrophins with 1 CBD), 11 CPAP3s (CPAPs with 3 CBDs) and 17 PMPs (PM proteins) with a variable number of CBDs, which are structural components of cuticle or of the PM. CBDs were also identified in enzymes of chitin metabolism including 6 chitinases and 7 chitin deacetylases encoded by 6 and 5 genes, respectively. RNA-seq analysis confirmed that PMP and CPAP genes have differential spatial expression patterns. The expression of PMP genes is midgut-specific, while CPAP genes are widely expressed in different cuticle forming tissues. Phylogenetic analysis of CBDs of proteins in insects belonging to different orders revealed that CPAP1s from different species constitute a separate family with 16 different groups, including 6 new groups identified in this study. The CPAP3s are clustered into a separate family of 7 groups present in all insect orders. Altogether, they reveal that duplication events of CBDs in CPAP1s and CPAP3s occurred prior to the evolutionary radiation of insect species. In contrast to the CPAPs, all CBDs from individual PMPs are generally clustered and distinct from other PMPs in the same species in phylogenetic analyses, indicating that the duplication of CBDs in each of these PMPs occurred after divergence of insect species. Phylogenetic analysis of these three CBP families showed that the CBDs in CPAP1s form a clearly separate family, while those found in PMPs and CPAP3s were clustered together in the phylogenetic tree. For chitinases and chitin deacetylases, most of phylogenetic analysis performed with the CBD sequences resulted in similar clustering to the one obtained by using catalytic domain sequences alone, suggesting that CBDs were incorporated into these enzymes and evolved in tandem with the catalytic domains before the diversification of different insect orders. Based on these results, the evolution of CBDs in insect CBPs is discussed to provide a new insight into the CBD sequence structure and diversity, and their evolution and expression in insects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fate, behavior, and bioavailability of metal and metal oxide nanomaterials in terrestrial ecosystems

NASA Astrophysics Data System (ADS)

Bertsch, P. M.; Unrine, J. M.; Judy, J.; Tsyusko, O.

2012-12-01

Despite the benefits that are currently being manifested and those transformative breakthroughs that will undoubtedly result from advances in nanotechnology, concerns surrounding the potential negative impacts to the environment and human health and welfare continue to emerge. Information on the transport and fate of manufactured nanomaterials (MNMs) in the environment and on their potential effects to human and ecological receptors is emerging at an increasing rate. Notwithstanding these developments, the research enterprise focused on the environmental implications of nanotechnology is in its infancy and few unifying principles have yet to emerge. This lack of unanimity is related to many factors including, the vast diversity in chemical composition, size, shape, and surface chemical properties of MNMs, as well as the range of receptor species and cell lines investigated. Additionally, the large variation in exposure methodologies employed by various investigators as well as the discrepancies in the amount and quality of characterization data collected to support specific conclusions, provide major challenges for developing unifying concepts and principles. As the utilization of MNMs for a large variety of applications is currently in an exponential growth phase, there is great urgency to develop information that can be used to identify priority areas for assessing risks to humans and the environment, as well as in developing potential mitigation strategies. We have been investigating the fate, behavior, and potential impacts of MNMs released into terrestrial ecosystems by examining the bioavailability and toxicity as well as the trophic transfer of a range of metal and metal oxide nanoparticles (Ag, Au, Cu, TiO2, ZnO, CeO2) to microorganisms, detritivores, and plants. Interdisciplinary studies include the characterization of the nanoparticles and aged nanoparticles in complex media, the distribution of nanoparticles in biological tissues, nanoparticle toxicity as referenced to the free metal ion concentration, and gene and protein expression associated with nanoparticle exposure. The results demonstrate the importance and challenges of characterization of nanoparticles under varying chemical conditions associated with exposure media. We have also demonstrated that metal and metal oxide nanoparticles are bioavailable and can be toxic to microorganisms, plants, nematodes, and earthworms. The results also suggest a different spatial distribution in tissues as well as unique toxicity mechanisms compared to the free metal ion concentration. Ongoing studies are evaluating the propensity for nanoparticles to be transferred from one trophic level to the next by feeding pre-exposed microorganisms (B. vietnamensis) to the nematode, C. elegans, pre-exposed earthworms (E. fetida) to bullfrogs (R. catesbeiana) and pre-exposed tobacco plants (Nicotiana tabacum L. cv Xanthi) to the caterpillar, tobacco horn worm (Manduca sexta), to test the hypothesis that surface modification of nanoparticles by peptides or other biomolecules facilitate the transmembrane transport of nanoparticles, thus enhancing the bioavailability to higher trophic levels.

Aspects of cuticular sclerotization in the locust, Scistocerca gregaria, and the beetle, Tenebrio molitor.

PubMed

Andersen, Svend Olav; Roepstorff, Peter

2007-03-01

The number of reactive amino groups in cuticular proteins decreases during the early period of insect cuticular sclerotization, presumably due to reaction with oxidation products of N-acetyldopamine (NADA) and N-beta-alanyldopamine (NBAD). We have quantitated the decrease in cuticular N-terminal amino groups and lysine epsilon-amino groups during the first 24h of sclerotization in adult locusts, Schistocerca gregaria, and in larval and adult beetles, Tenebrio molitor, as well as the increase in beta-alanine amino groups in Tenebrio cuticle. The results indicate that nearly all glycine N-terminal groups and a significant part of the epsilon-amino groups from lysine residues are involved in the sclerotization process in both locusts and Tenebrio. A pronounced increase in the amount of free beta-alanine amino groups was observed in cuticle from adult Tenebrio and to a lesser extent also in Tenebrio larval cuticle, but from locust cuticle no beta-alanine was obtained. Hydrolysis of sclerotized cuticles from locusts and Tenebrio by dilute hydrochloric acid released a large number of compounds containing amino acids linked to catecholic moieties. Products have been identified which contain histidine residues linked via their imidazole group to the beta-position of various catechols, such as dopamine, 3,4-dihydroxyphenyl-ethanol (DOPET), and 3,4-dihydroxyphenyl-acetaldehyde (DOPALD), and a ketocatecholic compound has also been identified composed of lysine linked via its epsilon-amino group to the alpha-carbon atom of 3,4-dihydroxyacetophenone. Some of the hydrolysis products have previously been obtained from sclerotized pupal cuticle of Manduca sexta [Xu, R., Huang, X., Hopkins, T.L., Kramer, K.J., 1997. Catecholamine and histidyl protein cross-linked structures in sclerotized insect cuticle. Insect Biochemistry and Molecular Biology 27, 101-108; Kerwin, J.L., Turecek, F., Xu, R., Kramer, K.J., Hopkins, T.L., Gatlin, C.L., Yates, J.R., 1999. Mass spectrometric analysis of catechol-histidine adducts from insect cuticle. Analytical Biochemistry 268, 229-237; Kramer, K.J., Kanost, M.R., Hopkins, T.L., Jiang, H., Zhu, Y.C., Xu, R., Kerwin, J.L., Turecek, F., 2001. Oxidative conjugation of catechols with proteins in insect skeletal systems. Tetrahedron 57, 385-392], but the lysine-dihydroxyacetophenone compound and the histidine-DOPALD adduct have not been reported before. It is suggested that the compounds are derived from NADA and NBAD residues which were incorporated into the cuticle during sclerotization, and that the lysine-dihydroxyacetophenone as well as the DOPET and DOPALD containing adducts are degradation products derived from cross-links between the cuticular proteins, whereas the dopamine-containing adducts are derived from a non-crosslinking reaction product.

Osteopontin CD44 Interaction: A Novel Mechanism for the Selective Homing of Breast Tumor Cells into Bone

DTIC Science & Technology

2001-06-01

285, 1182-1186. Giunciuglio, D., T. Cai, C. Filanti, P. Manduca, and A. Albini. (1995) Cancer Letters. 97:69-74. Guirguis R, Margulies I, Taraboletti G...1998; 111,3119-27. Schirrmacher V. Sci. USA 87,1620-24. Shekhar, P. V., C. J. Aslakson, and F. R. Miller . (1993) Seminars in Cancer Biology. 4:193-204...in a mouse model . Science 279:377-380 Even though uncontrolled growth does not inevitably 4. Brooks PC, Montgomery AMP, Rosenfeld M, Reisfeld RA, lead

Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway?

PubMed Central

2010-01-01

Background Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. Results The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the neuropil volume in its brain. The paired olfactory neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid neuropils. The hemiellipsoid body neuropil is organized into parallel neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. Conclusions In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta, by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell. PMID:20831795

Thinking Like a Scientist: The RITES Path for K-12 Students to Learn the Scientific Method

NASA Astrophysics Data System (ADS)

Murray, D. P.; Dooley, H., Jr.; Cardace, D.

2015-12-01

Bringing Research on Learning to the Geosciences (Manduca et al, 2002) stated that "An overaching goal for geoscience education is to help every student to 'think like a scientist'", and that continues to challenge geoscience education. The Rhode Island Technology Enhanced Science (RITES) project addresses that goal, and this presentation chronicles that successful effort. RITES strives to improve science education by providing professional development (PD) to the majority of science teachers at the 5th through 12th grade levels throughout Rhode Island. The PD is presented through ~forty 2.5 day workshops that emphasize the innovative use of technology and best teaching practices, consistent with the recommendations detailed in Manduca et al (2002). The presentation will focus on two of these workshops that provide middle and high school teachers with strategies and techniques for guiding student-run explorations of earthquakes as a result of tectonic plate movements. Teachers address these topics much as a scientist would by carrying out the following activities: 1) Identifying the relationships between faults, EQs and plate boundaries; 2) Using GPS data to quantify interseismic deformation; 3) Constructing an Earthquake machine; and 4) Scaling their observations from desktop to crustal scale, and (5) Using the results to forecast earthquakes along the SAF and to estimate the magnitude of earthquakes on ancient faults. As it is unrealistic to expect teachers to be able to incorporate all of this material into their syllabi, we have introduced the concept of Subtle Shifts (Exploratorium, 2006) as a means by which they can easily blend workshop material into their existing courses. Teacher surveys reflect a high level of satisfaction (81-100%), and pre- and post-evaluations show significant normalized gains (Hake, 1998), in about 90% of the courses. Moreover, students of RITES teachers demonstrate statistically significant gains in inquiry skills and content knowledge.

Molecular characteristics of mammalian and insect amino acid transporters: implications for amino acid homeostasis.

PubMed

Castagna, M; Shayakul, C; Trotti, D; Sacchi, V F; Harvey, W R; Hediger, M A

1997-01-01

In mammalian cells, the uptake of amino acids is mediated by specialized, energy-dependent and passive transporters with overlapping substrate specificities. Most energy-dependent transporters are coupled either to the cotransport of Na+ or Cl- or to the countertransport of K+. Passive transporters are either facilitated transporters or channels. As a prelude to the molecular characterization of the different classes of transporters, we have isolated transporter cDNAs by expression-cloning with Xenopus laevis oocytes and we have characterized the cloned transporters functionally by uptake studies into oocytes using radiolabelled substrates and by electrophysiology to determine substrate-evoked currents. Mammalian transporters investigated include the dibasic and neutral amino acid transport protein D2/NBAT (system b0+) and the Na(+)- and K(+)-dependent neuronal and epithelial high-affinity glutamate transporter EAAC1 (system XAG-). A detailed characterization of these proteins has provided new information on transport characteristics and mechanisms for coupling to different inorganic ions. This work has furthermore advanced our understanding of the roles these transporters play in amino acid homeostasis and in various pathologies. For example, in the central nervous system, glutamate transporters are critically important in maintaining the extracellular glutamate concentration below neurotoxic levels, and defects of the human D2 gene have been shown to account for the formation of kidney stones in patients with cystinuria. Using similar approaches, we are investigating the molecular characteristics of K(+)-coupled amino acid transporters in the larval lepidopteran insect midgut. In the larval midgut, K+ is actively secreted into the lumen through the concerted action of an apical H+ V-ATPase and an apical K+/2H+ antiporter, thereby providing the driving force for absorption of amino acids. In vivo, the uptake occurs at extremely high pH (pH 10) and is driven by a large potential difference (approximately -200 mV). Studies with brush-border membrane vesicles have shown that there are several transport systems in the larval intestine with distinct amino acid and cation specificities. In addition to K+, Na+ can also be coupled to amino acid uptake at lower pH, but the Na+/K+ ratio of the hemolymph is so low that K+ is probably the major coupling ion in vivo. The neutral amino acid transport system of larval midgut has been studied most extensively. Apart from its cation selectivity, it appears to be related to the amino acid transport system B previously characterized in vertebrate epithelial cells. Both systems have a broad substrate range which excludes 2-(methylamino)-isobutyric acid, an amino acid analog accepted by the mammalian Na(+)-coupled system A. In order to gain insights into the K(+)-coupling mechanism and into amino acid and K+ homeostasis in insects, current studies are designed to delineate the molecular characteristics of these insect transporters. Recent data showed that injection of mRNA prepared from the midgut of Manduca sexta into Xenopus laevis oocytes induced a 1.5- to 2.5-fold stimulation of the Na(+)-dependent uptake of both leucine and phenylalanine (0.2 mmoll-1, pH 8). The molecular cloning of these transporters is now in progress. Knowledge of their unique molecular properties could be exploited in the future to control disease vectors and insect pests.

Schlieren photography on freely flying hawkmoth.

PubMed

Liu, Yun; Roll, Jesse; Van Kooten, Stephen; Deng, Xinyan

2018-05-01

The aerodynamic force on flying insects results from the vortical flow structures that vary both spatially and temporally throughout flight. Due to these complexities and the inherent difficulties in studying flying insects in a natural setting, a complete picture of the vortical flow has been difficult to obtain experimentally. In this paper, Schlieren , a widely used technique for highspeed flow visualization, was adapted to capture the vortex structures around freely flying hawkmoth ( Manduca ). Flow features such as leading-edge vortex, trailing-edge vortex, as well as the full vortex system in the wake were visualized directly. Quantification of the flow from the Schlieren images was then obtained by applying a physics-based optical flow method, extending the potential applications of the method to further studies of flying insects. © 2018 The Author(s).

Robustness of non-interdependent and interdependent networks against dependent and adaptive attacks

NASA Astrophysics Data System (ADS)

Tyra, Adam; Li, Jingtao; Shang, Yilun; Jiang, Shuo; Zhao, Yanjun; Xu, Shouhuai

2017-09-01

Robustness of complex networks has been extensively studied via the notion of site percolation, which typically models independent and non-adaptive attacks (or disruptions). However, real-life attacks are often dependent and/or adaptive. This motivates us to characterize the robustness of complex networks, including non-interdependent and interdependent ones, against dependent and adaptive attacks. For this purpose, dependent attacks are accommodated by L-hop percolation where the nodes within some L-hop (L ≥ 0) distance of a chosen node are all deleted during one attack (with L = 0 degenerating to site percolation). Whereas, adaptive attacks are launched by attackers who can make node-selection decisions based on the network state in the beginning of each attack. The resulting characterization enriches the body of knowledge with new insights, such as: (i) the Achilles' Heel phenomenon is only valid for independent attacks, but not for dependent attacks; (ii) powerful attack strategies (e.g., targeted attacks and dependent attacks, dependent attacks and adaptive attacks) are not compatible and cannot help the attacker when used collectively. Our results shed some light on the design of robust complex networks.

The contribution of collective attack tactics in differentiating handball score efficiency.

PubMed

Rogulj, Nenad; Srhoj, Vatromir; Srhoj, Ljerka

2004-12-01

The prevalence of 19 elements of collective tactics in score efficient and score inefficient teams was analyzed in 90 First Croatian Handball League--Men games during the 1998-1999 season. Prediction variables were used to describe duration, continuity, system, organization and spatial direction of attacks. Analysis of the basic descriptive and distribution statistical parameters revealed normal distribution of all variables and possibility to use multivariate methods. Canonic discrimination analysis and analysis of variance showed the use of collective tactics elements on attacks to differ statistically significantly between the winning and losing teams. Counter-attacks and uninterrupted attacks predominate in winning teams. Other types of attacks such as long position attack, multiply interrupted attack, attack with one circle runner attack player/pivot, attack based on basic principles, attack based on group cooperation, attack based on independent action, attack based on group maneuvering, rightward directed attack and leftward directed attack predominate in losing teams. Winning teams were found to be clearly characterized by quick attacks against unorganized defense, whereas prolonged, interrupted position attacks against organized defense along with frequent and diverse tactical actions were characteristic of losing teams. The choice and frequency of using a particular tactical activity in position attack do not warrant score efficiency but usually are consequential to the limited anthropologic potential and low level of individual technical-tactical skills of the players in low-quality teams.

Predicting Factors of Zone 4 Attack in Volleyball.

PubMed

Costa, Gustavo C; Castro, Henrique O; Evangelista, Breno F; Malheiros, Laura M; Greco, Pablo J; Ugrinowitsch, Herbert

2017-06-01

This study examined 142 volleyball games of the Men's Super League 2014/2015 seasons in Brazil from which we analyzed 24-26 games of each participating team, identifying 5,267 Zone 4 attacks for further analysis. Within these Zone 4 attacks, we analyzed the association between the effect of the attack carried out and the separate effects of serve reception, tempo and type of attack. We found that the reception, tempo of attack, second tempo of attack, and power of diagonal attack were predictors of the attack effect in Zone 4. Moreover, placed attacks showed a tendency to not yield a score. In conclusion, winning points in high-level men's volleyball requires excellent receptions, a fast attack tempo and powerfully executed of attacks.

Breakthrough attacks in patients with hereditary angioedema receiving long-term prophylaxis are responsive to icatibant: findings from the Icatibant Outcome Survey.

PubMed

Aberer, Werner; Maurer, Marcus; Bouillet, Laurence; Zanichelli, Andrea; Caballero, Teresa; Longhurst, Hilary J; Perrin, Amandine; Andresen, Irmgard

2017-01-01

Patients with hereditary angioedema (HAE) due to C1-inhibitor deficiency (C1-INH-HAE) experience recurrent attacks of cutaneous or submucosal edema that may be frequent and severe; prophylactic treatments can be prescribed to prevent attacks. However, despite the use of long-term prophylaxis (LTP), breakthrough attacks are known to occur. We used data from the Icatibant Outcome Survey (IOS) to evaluate the characteristics of breakthrough attacks and the effectiveness of icatibant as a treatment option. Data on LTP use, attacks, and treatments were recorded. Attack characteristics, treatment characteristics, and outcomes (time to treatment, time to resolution, and duration of attack) were compared for attacks that occurred with versus without LTP. Data on 3228 icatibant-treated attacks from 448 patients with C1-INH-HAE were analyzed; 30.1% of attacks occurred while patients were using LTP. Attack rate, attack severity, and the distribution of attack sites were similar across all types of LTP used, and were comparable to the results found in patients who did not receive LTP. Attacks were successfully treated with icatibant; 82.5% of all breakthrough attacks were treated with a single icatibant injection without C1-INH rescue medication. Treatment outcomes were comparable for breakthrough attacks across all LTP types, and for attacks without LTP. Patients who use LTP should be aware that breakthrough attacks can occur, and such attacks can be severe. Thus, patients with C1-INH-HAE using LTP should have emergency treatment readily available. Data from IOS show that icatibant is effective for the treatment of breakthrough attacks. Trial Registration NCT01034969.

A graph-based network-vulnerability analysis system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swiler, L.P.; Phillips, C.; Gaylor, T.

1998-05-03

This paper presents a graph based approach to network vulnerability analysis. The method is flexible, allowing analysis of attacks from both outside and inside the network. It can analyze risks to a specific network asset, or examine the universe of possible consequences following a successful attack. The analysis system requires as input a database of common attacks, broken into atomic steps, specific network configuration and topology information, and an attacker profile. The attack information is matched with the network configuration information and an attacker profile to create a superset attack graph. Nodes identify a stage of attack, for example themore » class of machines the attacker has accessed and the user privilege level he or she has compromised. The arcs in the attack graph represent attacks or stages of attacks. By assigning probabilities of success on the arcs or costs representing level of effort for the attacker, various graph algorithms such as shortest path algorithms can identify the attack paths with the highest probability of success.« less

A graph-based network-vulnerability analysis system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swiler, L.P.; Phillips, C.; Gaylor, T.

1998-01-01

This report presents a graph-based approach to network vulnerability analysis. The method is flexible, allowing analysis of attacks from both outside and inside the network. It can analyze risks to a specific network asset, or examine the universe of possible consequences following a successful attack. The analysis system requires as input a database of common attacks, broken into atomic steps, specific network configuration and topology information, and an attacker profile. The attack information is matched with the network configuration information and an attacker profile to create a superset attack graph. Nodes identify a stage of attack, for example the classmore » of machines the attacker has accessed and the user privilege level he or she has compromised. The arcs in the attack graph represent attacks or stages of attacks. By assigning probabilities of success on the arcs or costs representing level-of-effort for the attacker, various graph algorithms such as shortest-path algorithms can identify the attack paths with the highest probability of success.« less

Method and tool for network vulnerability analysis

DOEpatents

Swiler, Laura Painton [Albuquerque, NM; Phillips, Cynthia A [Albuquerque, NM

2006-03-14

A computer system analysis tool and method that will allow for qualitative and quantitative assessment of security attributes and vulnerabilities in systems including computer networks. The invention is based on generation of attack graphs wherein each node represents a possible attack state and each edge represents a change in state caused by a single action taken by an attacker or unwitting assistant. Edges are weighted using metrics such as attacker effort, likelihood of attack success, or time to succeed. Generation of an attack graph is accomplished by matching information about attack requirements (specified in "attack templates") to information about computer system configuration (contained in a configuration file that can be updated to reflect system changes occurring during the course of an attack) and assumed attacker capabilities (reflected in "attacker profiles"). High risk attack paths, which correspond to those considered suited to application of attack countermeasures given limited resources for applying countermeasures, are identified by finding "epsilon optimal paths."

About Heart Attacks

MedlinePlus

... Artery Disease Venous Thromboembolism Aortic Aneurysm More About Heart Attacks Updated:Jan 11,2018 A heart attack is ... coronary artery damage leads to a heart attack . Heart Attack Questions and Answers What is a heart attack? ...

A graph-based system for network-vulnerability analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swiler, L.P.; Phillips, C.

1998-06-01

This paper presents a graph-based approach to network vulnerability analysis. The method is flexible, allowing analysis of attacks from both outside and inside the network. It can analyze risks to a specific network asset, or examine the universe of possible consequences following a successful attack. The graph-based tool can identify the set of attack paths that have a high probability of success (or a low effort cost) for the attacker. The system could be used to test the effectiveness of making configuration changes, implementing an intrusion detection system, etc. The analysis system requires as input a database of common attacks,more » broken into atomic steps, specific network configuration and topology information, and an attacker profile. The attack information is matched with the network configuration information and an attacker profile to create a superset attack graph. Nodes identify a stage of attack, for example the class of machines the attacker has accessed and the user privilege level he or she has compromised. The arcs in the attack graph represent attacks or stages of attacks. By assigning probabilities of success on the arcs or costs representing level-of-effort for the attacker, various graph algorithms such as shortest-path algorithms can identify the attack paths with the highest probability of success.« less

Application of Cellular Automata to Detection of Malicious Network Packets

ERIC Educational Resources Information Center

Brown, Robert L.

2014-01-01

A problem in computer security is identification of attack signatures in network packets. An attack signature is a pattern of bits that characterizes a particular attack. Because there are many kinds of attacks, there are potentially many attack signatures. Furthermore, attackers may seek to avoid detection by altering the attack mechanism so that…

Cooperating attackers in neural cryptography.

PubMed

Shacham, Lanir N; Klein, Einat; Mislovaty, Rachel; Kanter, Ido; Kinzel, Wolfgang

2004-06-01

A successful attack strategy in neural cryptography is presented. The neural cryptosystem, based on synchronization of neural networks by mutual learning, has been recently shown to be secure under different attack strategies. The success of the advanced attacker presented here, called the "majority-flipping attacker," does not decay with the parameters of the model. This attacker's outstanding success is due to its using a group of attackers which cooperate throughout the synchronization process, unlike any other attack strategy known. An analytical description of this attack is also presented, and fits the results of simulations.

Terrorist Attacks Escalate in Frequency and Fatalities Preceding Highly Lethal Attacks

PubMed Central

Martens, Andy; Sainudiin, Raazesh; Sibley, Chris G.; Schimel, Jeff; Webber, David

2014-01-01

Highly lethal terrorist attacks, which we define as those killing 21 or more people, account for 50% of the total number of people killed in all terrorist attacks combined, yet comprise only 3.5% of terrorist attacks. Given the disproportionate influence of these incidents, uncovering systematic patterns in attacks that precede and anticipate these highly lethal attacks may be of value for understanding attacks that exact a heavy toll on life. Here we examined whether the activity of terrorist groups escalates–both in the number of people killed per attack and in the frequency of attacks–leading up to highly lethal attacks. Analyses of terrorist attacks drawn from a state-of-the-art international terrorism database (The Global Terrorism Database) showed evidence for both types of escalation leading up to highly lethal attacks, though complexities to the patterns emerged as well. These patterns of escalation do not emerge among terrorist groups that never commit a highly lethal attack. PMID:24755753

Causal Attribution, Perceived Benefits, and Morbidity After a Heart Attack: An 8-Year Study.

ERIC Educational Resources Information Center

Affleck, Glenn; And Others

1987-01-01

Interviewed heart attack victims (N=287) seven weeks and eight years after their attack. Explored interrelations among causal attributions for the attack, survivor morbidity, and heart attack recurrence. Found that patients who cited benefits from their misfortune seven weeks after the first attack were less likely to have another attack and had…

On Patarin's Attack against the lIC Scheme

NASA Astrophysics Data System (ADS)

Ogura, Naoki; Uchiyama, Shigenori

In 2007, Ding et al. proposed an attractive scheme, which is called the l-Invertible Cycles (lIC) scheme. lIC is one of the most efficient multivariate public-key cryptosystems (MPKC); these schemes would be suitable for using under limited computational resources. In 2008, an efficient attack against lIC using Gröbner basis algorithms was proposed by Fouque et al. However, they only estimated the complexity of their attack based on their experimental results. On the other hand, Patarin had proposed an efficient attack against some multivariate public-key cryptosystems. We call this attack Patarin's attack. The complexity of Patarin's attack can be estimated by finding relations corresponding to each scheme. In this paper, we propose an another practical attack against the lIC encryption/signature scheme. We estimate the complexity of our attack (not experimentally) by adapting Patarin's attack. The attack can be also applied to the lIC- scheme. Moreover, we show some experimental results of a practical attack against the lIC/lIC- schemes. This is the first implementation of both our proposed attack and an attack based on Gröbner basis algorithm for the even case, that is, a parameter l is even.

Machine Learning Methods for Attack Detection in the Smart Grid.

PubMed

Ozay, Mete; Esnaola, Inaki; Yarman Vural, Fatos Tunay; Kulkarni, Sanjeev R; Poor, H Vincent

2016-08-01

Attack detection problems in the smart grid are posed as statistical learning problems for different attack scenarios in which the measurements are observed in batch or online settings. In this approach, machine learning algorithms are used to classify measurements as being either secure or attacked. An attack detection framework is provided to exploit any available prior knowledge about the system and surmount constraints arising from the sparse structure of the problem in the proposed approach. Well-known batch and online learning algorithms (supervised and semisupervised) are employed with decision- and feature-level fusion to model the attack detection problem. The relationships between statistical and geometric properties of attack vectors employed in the attack scenarios and learning algorithms are analyzed to detect unobservable attacks using statistical learning methods. The proposed algorithms are examined on various IEEE test systems. Experimental analyses show that machine learning algorithms can detect attacks with performances higher than attack detection algorithms that employ state vector estimation methods in the proposed attack detection framework.

Split-second escape decisions in blue tits (Parus caeruleus)

NASA Astrophysics Data System (ADS)

Lind, Johan; Kaby, Ulrika; Jakobsson, Sven

2002-07-01

Bird mortality is heavily affected by birds of prey. Under attack, take-off is crucial for survival and even minor mistakes in initial escape response can have devastating consequences. Birds may respond differently depending on the character of the predator's attack and these split-second decisions were studied using a model merlin (Falco columbarius) that attacked feeding blue tits (Parus caeruleus) from two different attack angles in two different speeds. When attacked from a low attack angle they took off more steeply than when attacked from a high angle. This is the first study to show that escape behaviour also depends on predator attack speed. The blue tits responded to a high-speed attack by dodging sideways more often than when attacked at a low speed. Escape speed was not significantly affected by the different treatments. Although they have only a split-second before escaping an attack, blue tits do adjust their escape strategy to the prevailing attack conditions.

Hybrid attacks on model-based social recommender systems

NASA Astrophysics Data System (ADS)

Yu, Junliang; Gao, Min; Rong, Wenge; Li, Wentao; Xiong, Qingyu; Wen, Junhao

2017-10-01

With the growing popularity of the online social platform, the social network based approaches to recommendation emerged. However, because of the open nature of rating systems and social networks, the social recommender systems are susceptible to malicious attacks. In this paper, we present a certain novel attack, which inherits characteristics of the rating attack and the relation attack, and term it hybrid attack. Furtherly, we explore the impact of the hybrid attack on model-based social recommender systems in multiple aspects. The experimental results show that, the hybrid attack is more destructive than the rating attack in most cases. In addition, users and items with fewer ratings will be influenced more when attacked. Last but not the least, the findings suggest that spammers do not depend on the feedback links from normal users to become more powerful, the unilateral links can make the hybrid attack effective enough. Since unilateral links are much cheaper, the hybrid attack will be a great threat to model-based social recommender systems.

Detecting Pulsing Denial-of-Service Attacks with Nondeterministic Attack Intervals

NASA Astrophysics Data System (ADS)

Luo, Xiapu; Chan, Edmond W. W.; Chang, Rocky K. C.

2009-12-01

This paper addresses the important problem of detecting pulsing denial of service (PDoS) attacks which send a sequence of attack pulses to reduce TCP throughput. Unlike previous works which focused on a restricted form of attacks, we consider a very broad class of attacks. In particular, our attack model admits any attack interval between two adjacent pulses, whether deterministic or not. It also includes the traditional flooding-based attacks as a limiting case (i.e., zero attack interval). Our main contribution is Vanguard, a new anomaly-based detection scheme for this class of PDoS attacks. The Vanguard detection is based on three traffic anomalies induced by the attacks, and it detects them using a CUSUM algorithm. We have prototyped Vanguard and evaluated it on a testbed. The experiment results show that Vanguard is more effective than the previous methods that are based on other traffic anomalies (after a transformation using wavelet transform, Fourier transform, and autocorrelation) and detection algorithms (e.g., dynamic time warping).

Cyber-Physical Attacks With Control Objectives

DOE PAGES

Chen, Yuan; Kar, Soummya; Moura, Jose M. F.

2017-08-18

This study studies attackers with control objectives against cyber-physical systems (CPSs). The goal of the attacker is to counteract the CPS's controller and move the system to a target state while evading detection. We formulate a cost function that reflects the attacker's goals, and, using dynamic programming, we show that the optimal attack strategy reduces to a linear feedback of the attacker's state estimate. By changing the parameters of the cost function, we show how an attacker can design optimal attacks to balance the control objective and the detection avoidance objective. In conclusion, we provide a numerical illustration based onmore » a remotely controlled helicopter under attack.« less

Cyber-Physical Attacks With Control Objectives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Yuan; Kar, Soummya; Moura, Jose M. F.

This study studies attackers with control objectives against cyber-physical systems (CPSs). The goal of the attacker is to counteract the CPS's controller and move the system to a target state while evading detection. We formulate a cost function that reflects the attacker's goals, and, using dynamic programming, we show that the optimal attack strategy reduces to a linear feedback of the attacker's state estimate. By changing the parameters of the cost function, we show how an attacker can design optimal attacks to balance the control objective and the detection avoidance objective. In conclusion, we provide a numerical illustration based onmore » a remotely controlled helicopter under attack.« less

Performance Improvement of Power Analysis Attacks on AES with Encryption-Related Signals

NASA Astrophysics Data System (ADS)

Lee, You-Seok; Lee, Young-Jun; Han, Dong-Guk; Kim, Ho-Won; Kim, Hyoung-Nam

A power analysis attack is a well-known side-channel attack but the efficiency of the attack is frequently degraded by the existence of power components, irrelative to the encryption included in signals used for the attack. To enhance the performance of the power analysis attack, we propose a preprocessing method based on extracting encryption-related parts from the measured power signals. Experimental results show that the attacks with the preprocessed signals detect correct keys with much fewer signals, compared to the conventional power analysis attacks.

Attacks on public telephone networks: technologies and challenges

NASA Astrophysics Data System (ADS)

Kosloff, T.; Moore, Tyler; Keller, J.; Manes, Gavin W.; Shenoi, Sujeet

2003-09-01

Signaling System 7 (SS7) is vital to signaling and control in America's public telephone networks. This paper describes a class of attacks on SS7 networks involving the insertion of malicious signaling messages via compromised SS7 network components. Three attacks are discussed in detail: IAM flood attacks, redirection attacks and point code spoofing attacks. Depending on their scale of execution, these attacks can produce effects ranging from network congestion to service disruption. Methods for detecting these denial-of-service attacks and mitigating their effects are also presented.

Novel mechanism of network protection against the new generation of cyber attacks

NASA Astrophysics Data System (ADS)

Milovanov, Alexander; Bukshpun, Leonid; Pradhan, Ranjit

2012-06-01

A new intelligent mechanism is presented to protect networks against the new generation of cyber attacks. This mechanism integrates TCP/UDP/IP protocol stack protection and attacker/intruder deception to eliminate existing TCP/UDP/IP protocol stack vulnerabilities. It allows to detect currently undetectable, highly distributed, low-frequency attacks such as distributed denial-of-service (DDoS) attacks, coordinated attacks, botnet, and stealth network reconnaissance. The mechanism also allows insulating attacker/intruder from the network and redirecting the attack to a simulated network acting as a decoy. As a result, network security personnel gain sufficient time to defend the network and collect the attack information. The presented approach can be incorporated into wireless or wired networks that require protection against known and the new generation of cyber attacks.

Fast WEP-Key Recovery Attack Using Only Encrypted IP Packets

NASA Astrophysics Data System (ADS)

Teramura, Ryoichi; Asakura, Yasuo; Ohigashi, Toshihiro; Kuwakado, Hidenori; Morii, Masakatu

Conventional efficient key recovery attacks against Wired Equivalent Privacy (WEP) require specific initialization vectors or specific packets. Since it takes much time to collect the packets sufficiently, any active attack should be performed. An Intrusion Detection System (IDS), however, will be able to prevent the attack. Since the attack logs are stored at the servers, it is possible to prevent such an attack. This paper proposes an algorithm for recovering a 104-bit WEP key from any IP packets in a realistic environment. This attack needs about 36, 500 packets with a success probability 0.5, and the complexity of our attack is equivalent to about 220 computations of the RC4 key setups. Since our attack is passive, it is difficult for both WEP users and administrators to detect our attack.

Robustness of coevolution in resolving prisoner's dilemma games on interdependent networks subject to attack

NASA Astrophysics Data System (ADS)

Liu, Penghui; Liu, Jing

2017-08-01

Recently, coevolution between strategy and network structure has been established as a rule to resolve social dilemmas and reach optimal situations for cooperation. Many follow-up researches have focused on studying how coevolution helps networks reorganize to deter the defectors and many coevolution methods have been proposed. However, the robustness of the coevolution rules against attacks have not been studied much. Since attacks may directly influence the original evolutionary process of cooperation, the robustness should be an important index while evaluating the quality of a coevolution method. In this paper, we focus on investigating the robustness of an elementary coevolution method in resolving the prisoner's dilemma game upon the interdependent networks. Three different types of time-independent attacks, named as edge attacks, instigation attacks and node attacks have been employed to test its robustness. Through analyzing the simulation results obtained, we find this coevolution method is relatively robust against the edge attack and the node attack as it successfully maintains cooperation in the population over the entire attack range. However, when the instigation probability of the attacked individuals is large or the attack range of instigation attack is wide enough, coevolutionary rule finally fails in maintaining cooperation in the population.

Security under Uncertainty: Adaptive Attackers Are More Challenging to Human Defenders than Random Attackers

PubMed Central

Moisan, Frédéric; Gonzalez, Cleotilde

2017-01-01

Game Theory is a common approach used to understand attacker and defender motives, strategies, and allocation of limited security resources. For example, many defense algorithms are based on game-theoretic solutions that conclude that randomization of defense actions assures unpredictability, creating difficulties for a human attacker. However, many game-theoretic solutions often rely on idealized assumptions of decision making that underplay the role of human cognition and information uncertainty. The consequence is that we know little about how effective these algorithms are against human players. Using a simplified security game, we study the type of attack strategy and the uncertainty about an attacker's strategy in a laboratory experiment where participants play the role of defenders against a simulated attacker. Our goal is to compare a human defender's behavior in three levels of uncertainty (Information Level: Certain, Risky, Uncertain) and three types of attacker's strategy (Attacker's strategy: Minimax, Random, Adaptive) in a between-subjects experimental design. Best defense performance is achieved when defenders play against a minimax and a random attack strategy compared to an adaptive strategy. Furthermore, when payoffs are certain, defenders are as efficient against random attack strategy as they are against an adaptive strategy, but when payoffs are uncertain, defenders have most difficulties defending against an adaptive attacker compared to a random attacker. We conclude that given conditions of uncertainty in many security problems, defense algorithms would be more efficient if they are adaptive to the attacker actions, taking advantage of the attacker's human inefficiencies. PMID:28690557

Numerical simulation of the optimal two-mode attacks for two-way continuous-variable quantum cryptography in reverse reconciliation

NASA Astrophysics Data System (ADS)

Zhang, Yichen; Li, Zhengyu; Zhao, Yijia; Yu, Song; Guo, Hong

2017-02-01

We analyze the security of the two-way continuous-variable quantum key distribution protocol in reverse reconciliation against general two-mode attacks, which represent all accessible attacks at fixed channel parameters. Rather than against one specific attack model, the expression of secret key rates of the two-way protocol are derived against all accessible attack models. It is found that there is an optimal two-mode attack to minimize the performance of the protocol in terms of both secret key rates and maximal transmission distances. We identify the optimal two-mode attack, give the specific attack model of the optimal two-mode attack and show the performance of the two-way protocol against the optimal two-mode attack. Even under the optimal two-mode attack, the performances of two-way protocol are still better than the corresponding one-way protocol, which shows the advantage of making double use of the quantum channel and the potential of long-distance secure communication using a two-way protocol.

Blind Data Attack on BGP Routers

DTIC Science & Technology

2017-03-01

implement blind attack protection, leaving long -standing connections, such as Border Gateway Protocol (BGP) sessions, vulnerable to exploitation. This...protection measures should a discovered vulnerability reduce attack complexity. 14. SUBJECT TERMS BGP, TCP, blind attack, blind data attack 15. NUMBER OF...implementations may not properly implement blind attack protection, leaving long -standing connections, such as BorderGateway Protocol (BGP) sessions

Research on high power intra-channel crosstalk attack in optical networks

NASA Astrophysics Data System (ADS)

Ren, Shuai; Zhang, Yinfa; Wang, Jingyu; Zhang, Jumei; Rao, Xuejun; Fang, Yuanyuan

2017-02-01

The mechanism of high power intra-channel crosstalk attack is analyzed theoretically and the conclusion that power of attack signal and crosstalk coefficient of optical switch are the main factors for which high power intra-channel have destructive effect on quality of legitimate signals is drawn. Effects of high power intra-channel crosstalk attack on quality of legitimate signals and its capability of attack propagation are investigated quantitatively by building the simulation system in VPI software. The results show that legitimate signals through the first and the second stage optical switch are affected by attack and legitimate signal through the third stage optical switch is almost unaffected by attack when power of original attack signal (OAS) is above 20dB more than that of legitimate signals and crosstalk coefficient of optical switch is -20dB at optical cross connect 1 (OXC1). High power intra-channel crosstalk attack has a certain capability of attack propagation. Attack capability of OAS can be propagated to OXC3 when power of OAS is 27dB more than that of legitimate signals and crosstalk coefficient of optical switch is -20dB. We also find that the secondary attack signal (SAS) does not have capability of attack propagation.

Warning Signs of Heart Attack, Stroke and Cardiac Arrest

MedlinePlus

... a Heart Attack WARNING SIGNS OF HEART ATTACK, STROKE & CARDIAC ARREST HEART ATTACK WARNING SIGNS CHEST DISCOMFORT ... nausea or lightheadedness. Learn more about heart attack STROKE WARNING SIGNS Spot a stroke F.A.S.T.: - ...

The role of mental disorder in attacks on European politicians 1990-2004.

PubMed

James, D V; Mullen, P E; Meloy, J R; Pathé, M T; Farnham, F R; Preston, L; Darnley, B

2007-11-01

The only systematic studies of attacks on public figures come from the USA. These studies de-emphasize the role of mental illness and suggest threats are of no predictive value. This study re-examines these questions through a study of attacks on European politicians. All non-terrorist attacks on elected politicians in Western Europe between 1990 and 2004 were analysed. Twenty-four attacks were identified, including five involving fatalities, and eight serious injuries. Ten attackers were psychotic, four drunk, nine politically motivated and one unclassifiable. Eleven attackers evidenced warning behaviours. The mentally disordered, most of whom gave warnings, were responsible for most of the fatal and seriously injurious attacks. A greater awareness of the link between delusional fixations on public figures and subsequent attacks could aid prevention. Equally importantly, recognition would encourage earlier intervention in people who, irrespective of whether they eventually attack, have delusional preoccupations which ruin their lives.

An Exploration of Hypotheses that Explain Herbivore and Pathogen Attack in Restored Plant Communities

PubMed Central

Blaisdell, G. Kai; Roy, Bitty A.; Pfeifer-Meister, Laurel; Bridgham, Scott D.

2015-01-01

Many hypotheses address the associations of plant community composition with natural enemies, including: (i) plant species diversity may reduce enemy attack, (ii) attack may increase as host abundance increases, (iii) enemy spillover may lead to increased attack on one host species due to transmission from another host species, or enemy dilution may lead to reduced attack on a host that would otherwise have more attack, (iv) physical characteristics of the plant community may influence attack, and (v) plant vigor may affect attack. Restoration experiments with replicated plant communities provide an exceptional opportunity to explore these hypotheses. To explore the relative predictive strengths of these related hypotheses and to investigate the potential effect of several restoration site preparation techniques, we surveyed arthropod herbivore and fungal pathogen attack on the six most common native plant species in a restoration experiment. Multi-model inference revealed a weak but consistent negative correlation with pathogen attack and host diversity across the plant community, and no correlation between herbivory and host diversity. Our analyses also revealed host species-specific relationships between attack and abundance of the target host species, other native plant species, introduced plant species, and physical community characteristics. We found no relationship between enemy attack and plant vigor. We found minimal differences in plant community composition among several diverse site preparation techniques, and limited effects of site preparation techniques on attack. The strongest associations of community characteristics with attack varied among plant species with no community-wide patterns, suggesting that no single hypothesis successfully predicts the dominant community-wide trends in enemy attack. PMID:25699672

Cyber attack analysis on cyber-physical systems: Detectability, severity, and attenuation strategy

NASA Astrophysics Data System (ADS)

Kwon, Cheolhyeon

Security of Cyber-Physical Systems (CPS) against malicious cyber attacks is an important yet challenging problem. Since most cyber attacks happen in erratic ways, it is usually intractable to describe and diagnose them systematically. Motivated by such difficulties, this thesis presents a set of theories and algorithms for a cyber-secure architecture of the CPS within the control theoretic perspective. Here, instead of identifying a specific cyber attack model, we are focused on analyzing the system's response during cyber attacks. Firstly, we investigate the detectability of the cyber attacks from the system's behavior under cyber attacks. Specifically, we conduct a study on the vulnerabilities in the CPS's monitoring system against the stealthy cyber attack that is carefully designed to avoid being detected by its detection scheme. After classifying three kinds of cyber attacks according to the attacker's ability to compromise the system, we derive the necessary and sufficient conditions under which such stealthy cyber attacks can be designed to cause the unbounded estimation error while not being detected. Then, the analytical design method of the optimal stealthy cyber attack that maximizes the estimation error is developed. The proposed stealthy cyber attack analysis is demonstrated with illustrative examples on Air Traffic Control (ATC) system and Unmanned Aerial Vehicle (UAV) navigation system applications. Secondly, in an attempt to study the CPSs' vulnerabilities in more detail, we further discuss a methodology to identify potential cyber threats inherent in the given CPSs and quantify the attack severity accordingly. We then develop an analytical algorithm to test the behavior of the CPS under various cyber attack combinations. Compared to a numerical approach, the analytical algorithm enables the prediction of the most effective cyber attack combinations without computing the severity of all possible attack combinations, thereby greatly reducing the computational cost. The proposed algorithm is validated through a linearized longitudinal motion of a UAV example. Finally, we propose an attack attenuation strategy via the controller design for CPSs that are robust to various types of cyber attacks. While the previous studies have investigated a secure control by assuming a specific attack strategy, in this research we propose a hybrid robust control scheme that contains multiple sub-controllers, each matched to a specific type of cyber attacks. Then the system can be adapted to various cyber attacks (including those that are not assumed for sub-controller design) by switching its sub-controllers to achieve the best performance. Then, a method for designing a secure switching logic to counter all possible cyber attacks is proposed and it verifies mathematically the system's performance and stability as well. The performance of the proposed control scheme is demonstrated by an example with the hybrid H2 - H-infinity controller applied to a UAV example.

Method for Integrated Simulation (MINTSIM)

DTIC Science & Technology

1976-01-01

sorties allocated to attack SAMs. FAPA = fraction of striking aircraft attacking air bases which attack parked aircraft in the open. TAAB...each striking aircraft. FAS = fraction of striking aircraft attacking air bases which attack sheltered aircraft. (NOTE: FAPA + FAS = 1.0

Finite Energy and Bounded Actuator Attacks on Cyber-Physical Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Djouadi, Seddik M; Melin, Alexander M; Ferragut, Erik M

As control system networks are being connected to enterprise level networks for remote monitoring, operation, and system-wide performance optimization, these same connections are providing vulnerabilities that can be exploited by malicious actors for attack, financial gain, and theft of intellectual property. Much effort in cyber-physical system (CPS) protection has focused on protecting the borders of the system through traditional information security techniques. Less effort has been applied to the protection of cyber-physical systems from intelligent attacks launched after an attacker has defeated the information security protections to gain access to the control system. In this paper, attacks on actuator signalsmore » are analyzed from a system theoretic context. The threat surface is classified into finite energy and bounded attacks. These two broad classes encompass a large range of potential attacks. The effect of theses attacks on a linear quadratic (LQ) control are analyzed, and the optimal actuator attacks for both finite and infinite horizon LQ control are derived, therefore the worst case attack signals are obtained. The closed-loop system under the optimal attack signals is given and a numerical example illustrating the effect of an optimal bounded attack is provided.« less

Web Forms and Untraceable DDoS Attacks

NASA Astrophysics Data System (ADS)

Jakobsson, Markus; Menczer, Filippo

We analyze a Web vulnerability that allows an attacker to perform an email-based attack on selected victims, using standard scripts and agents. What differentiates the attack we describe from other, already known forms of distributed denial of service (DDoS) attacks is that an attacker does not need to infiltrate the network in any manner - as is normally required to launch a DDoS attack. Thus, we see this type of attack as a poor man's DDoS. Not only is the attack easy to mount, but it is also almost impossible to trace back to the perpetrator. Along with descriptions of our attack, we demonstrate its destructive potential with (limited and contained) experimental results. We illustrate the potential impact of our attack by describing how an attacker can disable an email account by flooding its inbox; block competition during on-line auctions; harm competitors with an on-line presence; disrupt phone service to a given victim; disconnect mobile corporate leaders from their networks; and disrupt electronic elections. Finally, we propose a set of countermeasures that are light-weight, do not require modifications to the infrastructure, and can be deployed in a gradual manner.

Replacement Attack: A New Zero Text Watermarking Attack

NASA Astrophysics Data System (ADS)

Bashardoost, Morteza; Mohd Rahim, Mohd Shafry; Saba, Tanzila; Rehman, Amjad

2017-03-01

The main objective of zero watermarking methods that are suggested for the authentication of textual properties is to increase the fragility of produced watermarks against tampering attacks. On the other hand, zero watermarking attacks intend to alter the contents of document without changing the watermark. In this paper, the Replacement attack is proposed, which focuses on maintaining the location of the words in the document. The proposed text watermarking attack is specifically effective on watermarking approaches that exploit words' transition in the document. The evaluation outcomes prove that tested word-based method are unable to detect the existence of replacement attack in the document. Moreover, the comparison results show that the size of Replacement attack is estimated less accurate than other common types of zero text watermarking attacks.

Design and Analysis of an Enhanced Patient-Server Mutual Authentication Protocol for Telecare Medical Information System.

PubMed

Amin, Ruhul; Islam, S K Hafizul; Biswas, G P; Khan, Muhammad Khurram; Obaidat, Mohammad S

2015-11-01

In order to access remote medical server, generally the patients utilize smart card to login to the server. It has been observed that most of the user (patient) authentication protocols suffer from smart card stolen attack that means the attacker can mount several common attacks after extracting smart card information. Recently, Lu et al.'s proposes a session key agreement protocol between the patient and remote medical server and claims that the same protocol is secure against relevant security attacks. However, this paper presents several security attacks on Lu et al.'s protocol such as identity trace attack, new smart card issue attack, patient impersonation attack and medical server impersonation attack. In order to fix the mentioned security pitfalls including smart card stolen attack, this paper proposes an efficient remote mutual authentication protocol using smart card. We have then simulated the proposed protocol using widely-accepted AVISPA simulation tool whose results make certain that the same protocol is secure against active and passive attacks including replay and man-in-the-middle attacks. Moreover, the rigorous security analysis proves that the proposed protocol provides strong security protection on the relevant security attacks including smart card stolen attack. We compare the proposed scheme with several related schemes in terms of computation cost and communication cost as well as security functionalities. It has been observed that the proposed scheme is comparatively better than related existing schemes.

Simulation of Attacks for Security in Wireless Sensor Network.

PubMed

Diaz, Alvaro; Sanchez, Pablo

2016-11-18

The increasing complexity and low-power constraints of current Wireless Sensor Networks (WSN) require efficient methodologies for network simulation and embedded software performance analysis of nodes. In addition, security is also a very important feature that has to be addressed in most WSNs, since they may work with sensitive data and operate in hostile unattended environments. In this paper, a methodology for security analysis of Wireless Sensor Networks is presented. The methodology allows designing attack-aware embedded software/firmware or attack countermeasures to provide security in WSNs. The proposed methodology includes attacker modeling and attack simulation with performance analysis (node's software execution time and power consumption estimation). After an analysis of different WSN attack types, an attacker model is proposed. This model defines three different types of attackers that can emulate most WSN attacks. In addition, this paper presents a virtual platform that is able to model the node hardware, embedded software and basic wireless channel features. This virtual simulation analyzes the embedded software behavior and node power consumption while it takes into account the network deployment and topology. Additionally, this simulator integrates the previously mentioned attacker model. Thus, the impact of attacks on power consumption and software behavior/execution-time can be analyzed. This provides developers with essential information about the effects that one or multiple attacks could have on the network, helping them to develop more secure WSN systems. This WSN attack simulator is an essential element of the attack-aware embedded software development methodology that is also introduced in this work.

Heartburn or Chest Pain: When Is It Heart Attack?

MedlinePlus

Heartburn or heart attack: When to worry Severe heartburn and heart attack can be hard to tell apart. Understand how they typically ... flow to your heart (angina) or an actual heart attack. Heartburn, angina and heart attack may feel very ...

Know the Warning Signs of a Heart Attack

MedlinePlus

... No. 22 Know the Warning Signs of a Heart Attack What is a heart attack? Aheart attack happens when the blood vessels that ... hurting your heart muscle. Another name for a heart attack is myocardial infarction, or MI. If you have ...

Percolation of localized attack on isolated and interdependent random networks

NASA Astrophysics Data System (ADS)

Shao, Shuai; Huang, Xuqing; Stanley, H. Eugene; Havlin, Shlomo

2014-03-01

Percolation properties of isolated and interdependent random networks have been investigated extensively. The focus of these studies has been on random attacks where each node in network is attacked with the same probability or targeted attack where each node is attacked with a probability being a function of its centrality, such as degree. Here we discuss a new type of realistic attacks which we call a localized attack where a group of neighboring nodes in the networks are attacked. We attack a randomly chosen node, its neighbors, and its neighbor of neighbors and so on, until removing a fraction (1 - p) of the network. This type of attack reflects damages due to localized disasters, such as earthquakes, floods and war zones in real-world networks. We study, both analytically and by simulations the impact of localized attack on percolation properties of random networks with arbitrary degree distributions and discuss in detail random regular (RR) networks, Erdős-Rényi (ER) networks and scale-free (SF) networks. We extend and generalize our theoretical and simulation results of single isolated networks to networks formed of interdependent networks.

Stealthy false data injection attacks using matrix recovery and independent component analysis in smart grid

NASA Astrophysics Data System (ADS)

JiWei, Tian; BuHong, Wang; FuTe, Shang; Shuaiqi, Liu

2017-05-01

Exact state estimation is vital important to maintain common operations of smart grids. Existing researches demonstrate that state estimation output could be compromised by malicious attacks. However, to construct the attack vectors, a usual presumption in most works is that the attacker has perfect information regarding the topology and so on even such information is difficult to acquire in practice. Recent research shows that Independent Component Analysis (ICA) can be used for inferring topology information which can be used to originate undetectable attacks and even to alter the price of electricity for the profits of attackers. However, we found that the above ICA-based blind attack tactics is merely feasible in the environment with Gaussian noises. If there are outliers (device malfunction and communication errors), the Bad Data Detector will easily detect the attack. Hence, we propose a robust ICA based blind attack strategy that one can use matrix recovery to circumvent the outlier problem and construct stealthy attack vectors. The proposed attack strategies are tested with IEEE representative 14-bus system. Simulations verify the feasibility of the proposed method.

Shilling Attacks Detection in Recommender Systems Based on Target Item Analysis

PubMed Central

Zhou, Wei; Wen, Junhao; Koh, Yun Sing; Xiong, Qingyu; Gao, Min; Dobbie, Gillian; Alam, Shafiq

2015-01-01

Recommender systems are highly vulnerable to shilling attacks, both by individuals and groups. Attackers who introduce biased ratings in order to affect recommendations, have been shown to negatively affect collaborative filtering (CF) algorithms. Previous research focuses only on the differences between genuine profiles and attack profiles, ignoring the group characteristics in attack profiles. In this paper, we study the use of statistical metrics to detect rating patterns of attackers and group characteristics in attack profiles. Another question is that most existing detecting methods are model specific. Two metrics, Rating Deviation from Mean Agreement (RDMA) and Degree of Similarity with Top Neighbors (DegSim), are used for analyzing rating patterns between malicious profiles and genuine profiles in attack models. Building upon this, we also propose and evaluate a detection structure called RD-TIA for detecting shilling attacks in recommender systems using a statistical approach. In order to detect more complicated attack models, we propose a novel metric called DegSim’ based on DegSim. The experimental results show that our detection model based on target item analysis is an effective approach for detecting shilling attacks. PMID:26222882

TANDI: threat assessment of network data and information

NASA Astrophysics Data System (ADS)

Holsopple, Jared; Yang, Shanchieh Jay; Sudit, Moises

2006-04-01

Current practice for combating cyber attacks typically use Intrusion Detection Sensors (IDSs) to passively detect and block multi-stage attacks. This work leverages Level-2 fusion that correlates IDS alerts belonging to the same attacker, and proposes a threat assessment algorithm to predict potential future attacker actions. The algorithm, TANDI, reduces the problem complexity by separating the models of the attacker's capability and opportunity, and fuse the two to determine the attacker's intent. Unlike traditional Bayesian-based approaches, which require assigning a large number of edge probabilities, the proposed Level-3 fusion procedure uses only 4 parameters. TANDI has been implemented and tested with randomly created attack sequences. The results demonstrate that TANDI predicts future attack actions accurately as long as the attack is not part of a coordinated attack and contains no insider threats. In the presence of abnormal attack events, TANDI will alarm the network analyst for further analysis. The attempt to evaluate a threat assessment algorithm via simulation is the first in the literature, and shall open up a new avenue in the area of high level fusion.

Identifying and tracking attacks on networks: C3I displays and related technologies

NASA Astrophysics Data System (ADS)

Manes, Gavin W.; Dawkins, J.; Shenoi, Sujeet; Hale, John C.

2003-09-01

Converged network security is extremely challenging for several reasons; expanded system and technology perimeters, unexpected feature interaction, and complex interfaces all conspire to provide hackers with greater opportunities for compromising large networks. Preventive security services and architectures are essential, but in and of themselves do not eliminate all threat of compromise. Attack management systems mitigate this residual risk by facilitating incident detection, analysis and response. There are a wealth of attack detection and response tools for IP networks, but a dearth of such tools for wireless and public telephone networks. Moreover, methodologies and formalisms have yet to be identified that can yield a common model for vulnerabilities and attacks in converged networks. A comprehensive attack management system must coordinate detection tools for converged networks, derive fully-integrated attack and network models, perform vulnerability and multi-stage attack analysis, support large-scale attack visualization, and orchestrate strategic responses to cyber attacks that cross network boundaries. We present an architecture that embodies these principles for attack management. The attack management system described engages a suite of detection tools for various networking domains, feeding real-time attack data to a comprehensive modeling, analysis and visualization subsystem. The resulting early warning system not only provides network administrators with a heads-up cockpit display of their entire network, it also supports guided response and predictive capabilities for multi-stage attacks in converged networks.

Pre-attack signs and symptoms in cluster headache: Characteristics and time profile.

PubMed

Snoer, Agneta; Lund, Nunu; Beske, Rasmus; Jensen, Rigmor; Barloese, Mads

2018-05-01

Introduction In contrast to the premonitory phase of migraine, little is known about the pre-attack (prodromal) phase of a cluster headache. We aimed to describe the nature, prevalence, and duration of pre-attack symptoms in cluster headache. Methods Eighty patients with episodic cluster headache or chronic cluster headache, according to ICHD-3 beta criteria, were invited to participate. In this observational study, patients underwent a semi-structured interview where they were asked about the presence of 31 symptoms/signs in relation to a typical cluster headache attack. Symptoms included previously reported cluster headache pre-attack symptoms, premonitory migraine symptoms and accompanying symptoms of migraine and cluster headache. Results Pre-attack symptoms were reported by 83.3% of patients, with an average of 4.25 (SD 3.9) per patient. Local and painful symptoms, occurring with a median of 10 minutes before attack, were reported by 70%. Local and painless symptoms and signs, occurring with a median of 10 minutes before attack, were reported by 43.8% and general symptoms, occurring with a median of 20 minutes before attack, were reported by 62.5% of patients. Apart from a dull/aching sensation in the attack area being significantly ( p < 0.05) more frequent among men and episodic patients, compared with women and chronic patients respectively, no other differences in the prevalence of pre-attack symptoms were identified between groups. Conclusion Pre-attack symptoms are frequent in cluster headache. Since the origin of cluster headache attacks is still unresolved, studies of pre-attack symptoms could contribute to the understanding of cluster headache pathophysiology. Furthermore, identification and recognition of pre-attack symptoms could potentially allow earlier abortive treatment.

Shark attack-related injuries: Epidemiology and implications for plastic surgeons.

PubMed

Ricci, Joseph A; Vargas, Christina R; Singhal, Dhruv; Lee, Bernard T

2016-01-01

The increased media attention to shark attacks has led to a heightened fear and public awareness. Although few sharks are considered dangerous, attacks on humans can result in large soft tissue defects necessitating the intervention of reconstructive surgeons. This study aims to evaluate and describe the characteristics of shark-related injuries in order to improve treatment. The Global Shark Accident File, maintained by the Shark Research Institute (Princeton, NJ, USA), is a compilation of all known worldwide shark attacks. Database records since the 1900s were reviewed to identify differences between fatal and nonfatal attacks, including: geography, injury pattern, shark species, and victim activity. Since the 1900s, there have been 5034 reported shark attacks, of which 1205 (22.7%) were fatal. Although the incidence of attacks per decade has increased, the percentage of fatalities has decreased. Characteristics of fatal attacks included swimming (p = 0.001), boating (p = 0.001), three or more bite sites (p = 0.03), limb loss (p = 0.001), or tiger shark attack (p = 0.002). The most common attacks were bites to the legs (41.8%) or arms (18.4%), with limb loss occurring in 7% of attacks. Geographically, the majority of attacks occurred in North America (36.7%) and Australia (26.5%). Most attacks in the USA occurred in Florida (49.1%) and California (13.6%). Although rare, shark attacks result in devastating injuries to patients. As these injuries often involve multiple sites and limb loss, this creates a significant challenge for reconstructive surgeons. Proper identification of the characteristics of the attack can aid in providing optimal care for those affected. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Hereditary Angioedema Attacks Resolve Faster and Are Shorter after Early Icatibant Treatment

PubMed Central

Maurer, Marcus; Kaplan, Allen; Investigators, on behalf of I. O. S.

2013-01-01

Background Attacks of hereditary angioedema (HAE) are unpredictable and, if affecting the upper airway, can be lethal. Icatibant is used for physician- or patient self-administered symptomatic treatment of HAE attacks in adults. Its mode of action includes disruption of the bradykinin pathway via blockade of the bradykinin B2 receptor. Early treatment is believed to shorten attack duration and prevent severe outcomes; however, evidence to support these benefits is lacking. Objective To examine the impact of timing of icatibant administration on the duration and resolution of HAE type I and II attacks. Methods The Icatibant Outcome Survey is an international, prospective, observational study for patients treated with icatibant. Data on timings and outcomes of icatibant treatment for HAE attacks were collected between July 2009–February 2012. A mixed-model of repeated measures was performed for 426 attacks in 136 HAE type I and II patients. Results Attack duration was significantly shorter in patients treated <1 hour of attack onset compared with those treated ≥1 hour (6.1 hours versus 16.8 hours [p<0.001]). Similar significant effects were observed for <2 hours versus ≥2 hours (7.2 hours versus 20.2 hours [p<0.001]) and <5 hours versus ≥5 hours (8.0 hours versus 23.5 hours [p<0.001]). Treatment within 1 hour of attack onset also significantly reduced time to attack resolution (5.8 hours versus 8.8 hours [p<0.05]). Self-administrators were more likely to treat early and experience shorter attacks than those treated by a healthcare professional. Conclusion Early blockade of the bradykinin B2 receptor with icatibant, particularly within the first hour of attack onset, significantly reduced attack duration and time to attack resolution. PMID:23390491

Adaptive optimisation-offline cyber attack on remote state estimator

NASA Astrophysics Data System (ADS)

Huang, Xin; Dong, Jiuxiang

2017-10-01

Security issues of cyber-physical systems have received increasing attentions in recent years. In this paper, deception attacks on the remote state estimator equipped with the chi-squared failure detector are considered, and it is assumed that the attacker can monitor and modify all the sensor data. A novel adaptive optimisation-offline cyber attack strategy is proposed, where using the current and previous sensor data, the attack can yield the largest estimation error covariance while ensuring to be undetected by the chi-squared monitor. From the attacker's perspective, the attack is better than the existing linear deception attacks to degrade the system performance. Finally, some numerical examples are provided to demonstrate theoretical results.

Public knowledge of heart attack symptoms in Beijing residents.

PubMed

Zhang, Qing-Tan; Hu, Da-Yi; Yang, Jin-Gang; Zhang, Shou-Yan; Zhang, Xin-Quan; Liu, Shu-Shan

2007-09-20

Definitive treatment for heart attack is early reperfusion with either angioplasty or thrombolytic therapy, and the benefit is strictly time-dependent. Patient outcomes are improved with either therapy when initiated as soon as possible. Recognition of heart attack symptoms is logically tied to taking action to receive prompt emergency care. Inadequate knowledge of heart attack symptoms may prolong delay. The purpose of this study was to document knowledge about heart attack symptoms in Beijing residents and to identify the characteristics associated with increased knowledge of heart attack. A structured survey was conducted in 18 communities in Beijing from March 1 through June 10 in 2006. Addresses and participants were selected randomly following a stratification. The survey was designed to collect knowledge of heart attack symptoms from sampled adults in each community. A total of 4627 respondents completed the questionnaires correctly, and 50.29% of them were female. Totally 64.15% of the respondents reported chest pain or discomfort (common symptoms) as a symptom of heart attack; 75.38% reported at least one of the following eight symptoms as a symptom of heart attack: back pain, shortness of breath, arm pain or numbness, nausea or vomiting, neck, jaw or shoulder pain, epigastric pain, sweating, weakness (less common symptoms); 20.36% correctly reported four or more heart attack symptoms, only 7.4% knew all the correct heart attack symptoms, and 28.94% knew about reperfusion therapy for heart attack; 31.7% reported to call 120 or 999 while having a heart attack themselves; however 89.6% reported to call 120 or 999 when someone else is suffering from a heart attack. Very old persons and those with health insurance coverage, high education level, high household income, longer living in Beijing and previous experience with heart disease had greater knowledge of heart attack symptoms. Public knowledge of common heart attack symptoms as well as less common heart attack symptoms is deficient in Beijing residents. But their knowledge of calling emergency medical services when someone is having a heart attack is relatively adequate. Public health efforts are needed to increase the recognition of the major heart attack symptoms in both the general public and groups at high risk for an acute cardiac event, especially in socioeconomically disadvantaged subgroups, including persons with low education level, low household income, and no health insurance coverage.

Application distribution model and related security attacks in VANET

NASA Astrophysics Data System (ADS)

Nikaein, Navid; Kanti Datta, Soumya; Marecar, Irshad; Bonnet, Christian

2013-03-01

In this paper, we present a model for application distribution and related security attacks in dense vehicular ad hoc networks (VANET) and sparse VANET which forms a delay tolerant network (DTN). We study the vulnerabilities of VANET to evaluate the attack scenarios and introduce a new attacker`s model as an extension to the work done in [6]. Then a VANET model has been proposed that supports the application distribution through proxy app stores on top of mobile platforms installed in vehicles. The steps of application distribution have been studied in detail. We have identified key attacks (e.g. malware, spamming and phishing, software attack and threat to location privacy) for dense VANET and two attack scenarios for sparse VANET. It has been shown that attacks can be launched by distributing malicious applications and injecting malicious codes to On Board Unit (OBU) by exploiting OBU software security holes. Consequences of such security attacks have been described. Finally, countermeasures including the concepts of sandbox have also been presented in depth.

An Approach for Assessing Consequences of Potential Supply Chain and Insider Contributed Cyber Attacks on Nuclear Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chu, Tsong L.

The Stuxnet attack at the Natanz facility is an example of a targeted and successful cyber attack on a nuclear facility. Snowden's release of National Security Agency documents demonstrated the consequences of the insider threat. More recently, the United States tried to attack North Korea but failed, South Korea was attempting to attack North Korea, and both applied Stuxnet-like approaches. These sophisticated targeted attacks differ from web-site hacking events that are reported almost daily in the news mainly because targeted attacks require detailed design and operation information of the systems attacked and/or are often carried out by insiders. For instance,more » in order to minimize disruption of facilities around the world, Stuxnet remained idle until it recognized the specific configuration of the Natanz facility, demonstrating that the attackers possessed extremely detailed information about the facility. Such targeted cyber attacks could become a national-level military weapon and be used in coercion of hostile countries.« less

Improving the Rainbow Attack by Reusing Colours

NASA Astrophysics Data System (ADS)

Ågren, Martin; Johansson, Thomas; Hell, Martin

Hashing or encrypting a key or a password is a vital part in most network security protocols. The most practical generic attack on such schemes is a time memory trade-off attack. Such an attack inverts any one-way function using a trade-off between memory and execution time. Existing techniques include the Hellman attack and the rainbow attack, where the latter uses different reduction functions ("colours") within a table.

Simulation of Attacks for Security in Wireless Sensor Network

PubMed Central

Diaz, Alvaro; Sanchez, Pablo

2016-01-01

The increasing complexity and low-power constraints of current Wireless Sensor Networks (WSN) require efficient methodologies for network simulation and embedded software performance analysis of nodes. In addition, security is also a very important feature that has to be addressed in most WSNs, since they may work with sensitive data and operate in hostile unattended environments. In this paper, a methodology for security analysis of Wireless Sensor Networks is presented. The methodology allows designing attack-aware embedded software/firmware or attack countermeasures to provide security in WSNs. The proposed methodology includes attacker modeling and attack simulation with performance analysis (node’s software execution time and power consumption estimation). After an analysis of different WSN attack types, an attacker model is proposed. This model defines three different types of attackers that can emulate most WSN attacks. In addition, this paper presents a virtual platform that is able to model the node hardware, embedded software and basic wireless channel features. This virtual simulation analyzes the embedded software behavior and node power consumption while it takes into account the network deployment and topology. Additionally, this simulator integrates the previously mentioned attacker model. Thus, the impact of attacks on power consumption and software behavior/execution-time can be analyzed. This provides developers with essential information about the effects that one or multiple attacks could have on the network, helping them to develop more secure WSN systems. This WSN attack simulator is an essential element of the attack-aware embedded software development methodology that is also introduced in this work. PMID:27869710

Analytical Characterization of Internet Security Attacks

ERIC Educational Resources Information Center

Sellke, Sarah H.

2010-01-01

Internet security attacks have drawn significant attention due to their enormously adverse impact. These attacks includes Malware (Viruses, Worms, Trojan Horse), Denial of Service, Packet Sniffer, and Password Attacks. There is an increasing need to provide adequate defense mechanisms against these attacks. My thesis proposal deals with analytical…

The anatomy of a shark attack: a case report and review of the literature.

PubMed

Caldicott, D G; Mahajani, R; Kuhn, M

2001-07-01

Shark attacks are rare but are associated with a high morbidity and significant mortality. We report the case of a patient's survival from a shark attack and their subsequent emergency medical and surgical management. Using data from the International Shark Attack File, we review the worldwide distribution and incidence of shark attack. A review of the world literature examines the features which make shark attacks unique pathological processes. We offer suggestions for strategies of management of shark attack, and techniques for avoiding adverse outcomes in human encounters with these endangered creatures.

Distinguishing attack and second-preimage attack on encrypted message authentication codes (EMAC)

NASA Astrophysics Data System (ADS)

Ariwibowo, Sigit; Windarta, Susila

2016-02-01

In this paper we show that distinguisher on CBC-MAC can be applied to Encrypted Message Authentication Code (EMAC) scheme. EMAC scheme in general is vulnerable to distinguishing attack and second preimage attack. Distinguishing attack simulation on AES-EMAC using 225 message modifications, no collision have been found. According to second preimage attack simulation on AES-EMAC no collision found between EMAC value of S1 and S2, i.e. no second preimage found for messages that have been tested. Based on distinguishing attack simulation on truncated AES-EMAC we found collision in every message therefore we cannot distinguish truncated AES-EMAC with random function. Second-preimage attack is successfully performed on truncated AES-EMAC.

Novel Method For Low-Rate Ddos Attack Detection

NASA Astrophysics Data System (ADS)

Chistokhodova, A. A.; Sidorov, I. D.

2018-05-01

The relevance of the work is associated with an increasing number of advanced types of DDoS attacks, in particular, low-rate HTTP-flood. Last year, the power and complexity of such attacks increased significantly. The article is devoted to the analysis of DDoS attacks detecting methods and their modifications with the purpose of increasing the accuracy of DDoS attack detection. The article details low-rate attacks features in comparison with conventional DDoS attacks. During the analysis, significant shortcomings of the available method for detecting low-rate DDoS attacks were found. Thus, the result of the study is an informal description of a new method for detecting low-rate denial-of-service attacks. The architecture of the stand for approbation of the method is developed. At the current stage of the study, it is possible to improve the efficiency of an already existing method by using a classifier with memory, as well as additional information.

Heavy-tailed distribution of the SSH Brute-force attack duration in a multi-user environment

NASA Astrophysics Data System (ADS)

Lee, Jae-Kook; Kim, Sung-Jun; Park, Chan Yeol; Hong, Taeyoung; Chae, Huiseung

2016-07-01

Quite a number of cyber-attacks to be place against supercomputers that provide highperformance computing (HPC) services to public researcher. Particularly, although the secure shell protocol (SSH) brute-force attack is one of the traditional attack methods, it is still being used. Because stealth attacks that feign regular access may occur, they are even harder to detect. In this paper, we introduce methods to detect SSH brute-force attacks by analyzing the server's unsuccessful access logs and the firewall's drop events in a multi-user environment. Then, we analyze the durations of the SSH brute-force attacks that are detected by applying these methods. The results of an analysis of about 10 thousands attack source IP addresses show that the behaviors of abnormal users using SSH brute-force attacks are based on human dynamic characteristics of a typical heavy-tailed distribution.

An entangling-probe attack on Shor's algorithm for factorization

NASA Astrophysics Data System (ADS)

Azuma, Hiroo

2018-02-01

We investigate how to attack Shor's quantum algorithm for factorization with an entangling probe. We show that an attacker can steal an exact solution of Shor's algorithm outside an institute where the quantum computer is installed if he replaces its initialized quantum register with entangled qubits, namely the entangling probe. He can apply arbitrary local operations to his own probe. Moreover, we assume that there is an unauthorized person who helps the attacker to commit a crime inside the institute. He tells garbage data obtained from measurements of the quantum register to the attacker secretly behind a legitimate user's back. If the attacker succeeds in cracking Shor's algorithm, the legitimate user obtains a random answer and does not notice the attacker's illegal acts. We discuss how to detect the attacker. Finally, we estimate a probability that the quantum algorithm inevitably makes an error, of which the attacker can take advantage.

Use of the Panic Attack Questionnaire-IV to assess non-clinical panic attacks and limited symptom panic attacks in student and community samples.

PubMed

Norton, Peter J; Zvolensky, Michael J; Bonn-Miller, Marcel O; Cox, Brian J; Norton, G Ron

2008-10-01

Since its development in the mid-1980s, the Panic Attack Questionnaire (PAQ) has been one of the more, if not the most, commonly used self-report tools for assessing panic attacks. The usage of the instrument, however, has come amid potential concerns that instructions and descriptions may lead to an over-estimate of the prevalence of panic attacks. Furthermore, the instrument has not been revised since 1992, despite changes in DSM-IV criteria and more recent developments in the understanding of panic attacks. As a result, this paper describes a revision of the PAQ to improve the instruction and descriptive set, and to fully assess features of panic derived from recent conceptualizations. Students meeting DSM-IV panic attack criteria and those endorsing panic attacks, but not meeting criteria, showed few differences with the exception that those not meeting DSM-IV criteria typically reported a longer onset-to-peak intensity time than did Panickers. Results were cross-validated and extended using an independent Community Sample. A full descriptive phenomenology of panic attacks is described, and future directions for studying panic attacks using the PAQ are presented.

Command Disaggregation Attack and Mitigation in Industrial Internet of Things

PubMed Central

Zhu, Pei-Dong; Hu, Yi-Fan; Cui, Peng-Shuai; Zhang, Yan

2017-01-01

A cyber-physical attack in the industrial Internet of Things can cause severe damage to physical system. In this paper, we focus on the command disaggregation attack, wherein attackers modify disaggregated commands by intruding command aggregators like programmable logic controllers, and then maliciously manipulate the physical process. It is necessary to investigate these attacks, analyze their impact on the physical process, and seek effective detection mechanisms. We depict two different types of command disaggregation attack modes: (1) the command sequence is disordered and (2) disaggregated sub-commands are allocated to wrong actuators. We describe three attack models to implement these modes with going undetected by existing detection methods. A novel and effective framework is provided to detect command disaggregation attacks. The framework utilizes the correlations among two-tier command sequences, including commands from the output of central controller and sub-commands from the input of actuators, to detect attacks before disruptions occur. We have designed components of the framework and explain how to mine and use these correlations to detect attacks. We present two case studies to validate different levels of impact from various attack models and the effectiveness of the detection framework. Finally, we discuss how to enhance the detection framework. PMID:29065461

Command Disaggregation Attack and Mitigation in Industrial Internet of Things.

PubMed

Xun, Peng; Zhu, Pei-Dong; Hu, Yi-Fan; Cui, Peng-Shuai; Zhang, Yan

2017-10-21

A cyber-physical attack in the industrial Internet of Things can cause severe damage to physical system. In this paper, we focus on the command disaggregation attack, wherein attackers modify disaggregated commands by intruding command aggregators like programmable logic controllers, and then maliciously manipulate the physical process. It is necessary to investigate these attacks, analyze their impact on the physical process, and seek effective detection mechanisms. We depict two different types of command disaggregation attack modes: (1) the command sequence is disordered and (2) disaggregated sub-commands are allocated to wrong actuators. We describe three attack models to implement these modes with going undetected by existing detection methods. A novel and effective framework is provided to detect command disaggregation attacks. The framework utilizes the correlations among two-tier command sequences, including commands from the output of central controller and sub-commands from the input of actuators, to detect attacks before disruptions occur. We have designed components of the framework and explain how to mine and use these correlations to detect attacks. We present two case studies to validate different levels of impact from various attack models and the effectiveness of the detection framework. Finally, we discuss how to enhance the detection framework.

Lethality of sea lamprey attacks on lake trout in relation to location on the body surface

USGS Publications Warehouse

Bergstedt, Roger A.; Schneider, Clifford P.; O'Gorman, Robert

2001-01-01

We compared the locations of healed attack marks of the sea lamprey Petromyzon marinus on live lake trout Salvelinus namaycush with those of unhealed attack marks on dead lake trout to determine if the lethality of a sea lamprey attack was related to attack location. Lake trout were collected from Lake Ontario, live fish with gill nets in September 1985 and dead fish with trawls in October 1983−1986. Attack location was characterized by the percent distances from snout to tail and from the ventral to the dorsal midline. Kolmogorov−Smirnov two-sample tests did not detect significant differences in the distribution of attack location along either the anteroposterior axis or the dorsoventral axis. When attack locations were grouped into six anatomical regions historically used to record sea lamprey attacks, dead fish did not exhibit a significantly higher proportion of attacks in the more anterior regions. Even if the differences in attack location on live and dead fish were significant, they were too small to imply substantial spatial differences in attack lethality that should be accounted for when modeling the effects of sea lampreys feeding on lake trout. We suggest that the tendency for sea lamprey attacks to occur on the anterior half of the fish is related to the lower amplitude of lateral body movement there during swimming and thus the lower likelihood of being dislodged.

Serial agonistic attacks by greylag goose families, Anser anser, against the same opponent

PubMed Central

Scheiber, Isabella B.R.; Kotrschal, Kurt; Weiß, Brigitte M.

2011-01-01

It is known from primates that alliance partners may support each other’s interests in competition with others, for example, through repeated agonistic attacks against a particular individual. We examined serial aggressive interactions between greylag goose families and other flock members. We found that repeated attacks towards the same individual were common and that up to five serial attacks by family members followed an initial attack. Family size did not affect the frequency of such serial attacks. Juvenile geese evidently benefited most from active social support through serial attacks. About 60% of the juveniles’ lost primary interactions were subsequently reversed by another family member. This may be one of the reasons why juveniles rank higher in the social hierarchy than would be expected from their age and size alone. Losses in serial attacks predominantly occurred against other, presumably higher-ranking, family geese and ganders. We propose three major functions/consequences of serial attacks. Analogous to primates, serial attacks in greylag geese may serve to reinforce a losing experience of an opponent defeated in a preceding attack. On the side of the winning family, serial attacks may reinforce the experience of winning. Both winning and losing experiences are linked with physiological consequences in higher vertebrates, affecting the future social performance of winners or losers. Finally, serial attacks may signal the agonistic potential of a family to other flock members. This is supported by heart rate data, which indicate that greylags are competent to interpret third-party relationships. PMID:21984838

Khyâl attacks: a key idiom of distress among traumatized cambodia refugees.

PubMed

Hinton, Devon E; Pich, Vuth; Marques, Luana; Nickerson, Angela; Pollack, Mark H

2010-06-01

Traumatized Cambodian refugees with PTSD often complain of khyâl attacks. The current study investigates khyâl attacks from multiple perspectives and examines the validity of a model of how khyâl attacks are generated. The study found that khyâl attacks had commonly been experienced in the previous 4 weeks and that their severity was strongly correlated with the severity of PTSD (PTSD Checklist). It was found that khyâl attacks were triggered by various processes--such as worry, trauma recall, standing up, going to a mall--and that khyâl attacks almost always met panic attack criteria. It was also found that during a khyâl attack there was great fear that death might occur from bodily dysfunction. It was likewise found that a complex nosology of khyâl attacks exists that rates the attacks on a scale of severity, that the severity determines how the khyâl attacks should be treated and that those treatments are often complex. As illustrated by the article, khyâl attacks constitute a key aspect of trauma ontology in this group, a culturally specific experiencing of anxiety and trauma-related disorder. The article also contributes to the study of trauma somatics, that is, to the study of how trauma results in specific symptoms in a specific cultural context, showing that a key part of the trauma-somatic reticulum is often a cultural syndrome.

Cyber attacks against state estimation in power systems: Vulnerability analysis and protection strategies

NASA Astrophysics Data System (ADS)

Liu, Xuan

Power grid is one of the most critical infrastructures in a nation and could suffer a variety of cyber attacks. With the development of Smart Grid, false data injection attack has recently attracted wide research interest. This thesis proposes a false data attack model with incomplete network information and develops optimal attack strategies for attacking load measurements and the real-time topology of a power grid. The impacts of false data on the economic and reliable operations of power systems are quantitatively analyzed in this thesis. To mitigate the risk of cyber attacks, a distributed protection strategies are also developed. It has been shown that an attacker can design false data to avoid being detected by the control center if the network information of a power grid is known to the attacker. In practice, however, it is very hard or even impossible for an attacker to obtain all network information of a power grid. In this thesis, we propose a local load redistribution attacking model based on incomplete network information and show that an attacker only needs to obtain the network information of the local attacking region to inject false data into smart meters in the local region without being detected by the state estimator. A heuristic algorithm is developed to determine a feasible attacking region by obtaining reduced network information. This thesis investigates the impacts of false data on the operations of power systems. It has been shown that false data can be designed by an attacker to: 1) mask the real-time topology of a power grid; 2) overload a transmission line; 3) disturb the line outage detection based on PMU data. To mitigate the risk of cyber attacks, this thesis proposes a new protection strategy, which intends to mitigate the damage effects of false data injection attacks by protecting a small set of critical measurements. To further reduce the computation complexity, a mixed integer linear programming approach is also proposed to separate the power grid into several subnetworks, then distributed protection strategy is applied to each subnetwork.

Public knowledge of heart attack in a Nepalese population survey.

PubMed

Limbu, Yuba R; Malla, Rabi; Regmi, Shyam R; Dahal, Ramesh; Nakarmi, Hari L; Yonzan, Ganesh; Gartaula, Ritu P

2006-01-01

Limited knowledge of heart attack symptoms may prevent patients from seeking time-dependent thrombolytic therapy, an intervention that offers impressive survival benefit. Previous studies carried out in developed countries demonstrated a deficit of knowledge about a wide range of heart attack symptoms. The aim of this study was to describe knowledge of heart attack, knowledge of heart attack symptoms, and anticipated first response to symptoms among the lay public in Nepal. A total of 1192 participants (657 men and 535 women age 16 to 88 years old) were interviewed in a cross-sectional manner. Those <16 years of age, all health professionals, and individuals with a history of heart attack were excluded. A total of 862 (72.3%) participants had heard of heart attack. Significantly more male than female participants had heard of heart attack (P <.001). Of the respondents, 91.7% with >or=10 years of education (ED-2) had heard of heart of attack, whereas only 54% respondents with <10 years of education or who were illiterate (unable to read and write) (ED-1) had heard of heart attack, and in both the male and female populations, a higher percentage of the ED-2 group had heard of heart attack than the ED-1 group (92.6% vs. 60% and 85.6% vs. 49.6%, respectively). A significantly higher number of respondents from 31 to 50 years of age (AGE-2) had heard of heart attack than those 16 to 30 years of age (AGE-1) and those >50 years of age (AGE-3) (P <.001). Among 862 respondents who had heard of heart attack, 21.3% could not name any heart attack symptoms. A total of 16 different heart attack symptoms were named. Fainting or collapsing (48%), chest pain (22.4%), shortness of breath (9%), dizziness (8.4%), palpitations (7.4%), and sweating (7.4%) were the leading symptoms named by respondents. Fainting or collapsing and chest pain and shortness of breath were named more frequently among the ED-2 group respondents and the AGE-3 group men. Only 3.7% could name >or=2 typical heart attack symptoms. A significantly larger number of the ED-2 group named >or=2 typical symptoms than their counterparts (P <0.001). A large number (77.6%) of respondents preferred immediate hospital referral and/or doctor consultation after a heart attack. In Nepal, better-educated men are more aware of heart attack. Fainting or collapsing and chest pain and shortness of breath were leading heart attack symptoms named by the general population. Public heart attack awareness is not adequate and knowledge of wide range of heart attack symptoms is deficient in the Nepalese general population.

Heart attack

MedlinePlus

... infarction; Non-ST - elevation myocardial infarction; NSTEMI; CAD - heart attack; Coronary artery disease - heart attack ... made up of cholesterol and other cells. A heart attack may occur when: A tear in the ...

The effect of climate variability on urinary stone attacks: increased incidence associated with temperature over 18 °C: a population-based study.

PubMed

Park, Hyoung Keun; Bae, Sang Rak; Kim, Satbyul E; Choi, Woo Suk; Paick, Sung Hyun; Ho, Kim; Kim, Hyeong Gon; Lho, Yong Soo

2015-02-01

The aim of this study was to evaluate the effect of seasonal variation and climate parameters on urinary tract stone attack and investigate whether stone attack is increased sharply at a specific point. Nationwide data of total urinary tract stone attack numbers per month between January 2006 and December 2010 were obtained from the Korean Health Insurance Review and Assessment Service. The effects of climatic factors on monthly urinary stone attack were assessed using auto-regressive integrated moving average (ARIMA) regression method. A total of 1,702,913 stone attack cases were identified. Mean monthly and monthly average daily urinary stone attack cases were 28,382 ± 2,760 and 933 ± 85, respectively. The stone attack showed seasonal trends of sharp incline in June, a peak plateau from July to September, and a sharp decline after September. The correlation analysis showed that ambient temperature (r = 0.557, p < 0.001) and relative humidity (r = 0.513, p < 0.001) were significantly associated with urinary stone attack cases. However, after adjustment for trends and seasonality, ambient temperature was the only climate factor associated with the stone attack cases in ARIMA regression test (p = 0.04). Threshold temperature was estimated as 18.4 °C. Risk of urinary stone attack significantly increases 1.71% (1.02-2.41 %, 95% confidence intervals) with a 1 °C increase of ambient temperature above the threshold point. In conclusion, monthly urinary stone attack cases were changed according to seasonal variation. Among the climates variables, only temperature had consistent association with stone attack and when the temperature is over 18.4 °C, urinary stone attack would be increased sharply.

Reexperiencing symptoms, dissociation, and avoidance behaviors in daily life of patients with PTSD and patients with panic disorder with agoraphobia.

PubMed

Pfaltz, Monique C; Michael, Tanja; Meyer, Andrea H; Wilhelm, Frank H

2013-08-01

Panic attacks are frequently perceived as life threatening. Panic disorder (PD) patients may therefore experience symptoms of posttraumatic stress disorder (PTSD). The authors explored this in 28 healthy controls, 17 PTSD patients, and 24 PD patients with agoraphobia who completed electronic diaries 36 times during 1 week. Patient groups frequently reported dissociation as well as thoughts, memories, and reliving of their trauma or panic attacks. PTSD patients reported more trauma/panic attack thoughts (incidence rate ratio [IRR] = 2.9) and memories (IRR = 2.8) than PD patients. Patient groups relived their trauma or panic attacks equally frequently, and reported comparable bodily reactions and distress associated with trauma or panic attack memories. Clinical groups avoided trauma or panic attack reminders more often than healthy controls (avoidance of trauma- or panic attack-related thoughts (IRR = 8.0); avoidance of things associated with the trauma or panic attack (IRR = 40.7). PD patients avoided trauma or panic attack reminders less often than PTSD patients (avoidance of trauma- or panic attack-related thoughts [IRR = 2.5]; avoidance of things associated with the trauma or panic attack [IRR = 4.1]), yet these differences were nonsignificant when controlling for functional impairment. In conclusion, trauma-like symptoms are common in PD with agoraphobia and panic attacks may be processed similarly as trauma in PTSD. Copyright © 2013 International Society for Traumatic Stress Studies.

False Positive and False Negative Effects on Network Attacks

NASA Astrophysics Data System (ADS)

Shang, Yilun

2018-01-01

Robustness against attacks serves as evidence for complex network structures and failure mechanisms that lie behind them. Most often, due to detection capability limitation or good disguises, attacks on networks are subject to false positives and false negatives, meaning that functional nodes may be falsely regarded as compromised by the attacker and vice versa. In this work, we initiate a study of false positive/negative effects on network robustness against three fundamental types of attack strategies, namely, random attacks (RA), localized attacks (LA), and targeted attack (TA). By developing a general mathematical framework based upon the percolation model, we investigate analytically and by numerical simulations of attack robustness with false positive/negative rate (FPR/FNR) on three benchmark models including Erdős-Rényi (ER) networks, random regular (RR) networks, and scale-free (SF) networks. We show that ER networks are equivalently robust against RA and LA only when FPR equals zero or the initial network is intact. We find several interesting crossovers in RR and SF networks when FPR is taken into consideration. By defining the cost of attack, we observe diminishing marginal attack efficiency for RA, LA, and TA. Our finding highlights the potential risk of underestimating or ignoring FPR in understanding attack robustness. The results may provide insights into ways of enhancing robustness of network architecture and improve the level of protection of critical infrastructures.

The non-trusty clown attack on model-based speaker recognition systems

NASA Astrophysics Data System (ADS)

Farrokh Baroughi, Alireza; Craver, Scott

2015-03-01

Biometric detectors for speaker identification commonly employ a statistical model for a subject's voice, such as a Gaussian Mixture Model, that combines multiple means to improve detector performance. This allows a malicious insider to amend or append a component of a subject's statistical model so that a detector behaves normally except under a carefully engineered circumstance. This allows an attacker to force a misclassification of his or her voice only when desired, by smuggling data into a database far in advance of an attack. Note that the attack is possible if attacker has access to database even for a limited time to modify victim's model. We exhibit such an attack on a speaker identification, in which an attacker can force a misclassification by speaking in an unusual voice, and replacing the least weighted component of victim's model by the most weighted competent of the unusual voice of the attacker's model. The reason attacker make his or her voice unusual during the attack is because his or her normal voice model can be in database, and by attacking with unusual voice, the attacker has the option to be recognized as himself or herself when talking normally or as the victim when talking in the unusual manner. By attaching an appropriately weighted vector to a victim's model, we can impersonate all users in our simulations, while avoiding unwanted false rejections.

44 CFR 312.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... meaning of the listed terms are as follows: (a) The term attack means any attack or series of attacks by... population caused, or which would be caused, by an attack upon the United States, or by natural disaster, (2) to deal with the immediate emergency conditions which would be created by any such attack, or natural...

44 CFR 312.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... meaning of the listed terms are as follows: (a) The term attack means any attack or series of attacks by... population caused, or which would be caused, by an attack upon the United States, or by natural disaster, (2) to deal with the immediate emergency conditions which would be created by any such attack, or natural...

44 CFR 312.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... meaning of the listed terms are as follows: (a) The term attack means any attack or series of attacks by... population caused, or which would be caused, by an attack upon the United States, or by natural disaster, (2) to deal with the immediate emergency conditions which would be created by any such attack, or natural...

[Comparative analysis of phenomenology of paroxysms of atrial fibrillation and panic attacks].

PubMed

San'kova, T A; Solov'eva, A D; Nedostup, A V

2004-01-01

To study phenomenology of attacks of atrial fibrillation (AF) and to compare it with phenomenology of panic attacks for elucidation of pathogenesis of atrial fibrillation and for elaboration of rational therapeutic intervention including those aimed at correction of psychovegetative abnormalities. Patients with nonrheumatic paroxysmal AF (n=105) and 100 patients with panic attacks (n=100). Clinical, cardiological and neurological examination, analysis of patients complaints during attacks of AF, and comparison them with diagnostic criteria for panic attack. It was found that clinical picture of attacks of AF comprised vegetative, emotional and functional neurological phenomena similar to those characteristic for panic attacks. This similarity as well as positive therapeutic effect of clonazepam allowed to propose a novel pathogenic mechanism of AF attacks. Severity of psychovegetative disorders during paroxysm of AF could be evaluated by calculation of psychovegetative iudex: Psychovegetative index should be used for detection of panic attack-like component in clinical picture of AF paroxysm and thus for determination of indications for inclusion of vegetotropic drugs, e. g. clonazepam, in complex preventive therapy.

Security Assessment of Cyberphysical Digital Microfluidic Biochips.

PubMed

Ali, Sk Subidh; Ibrahim, Mohamed; Sinanoglu, Ozgur; Chakrabarty, Krishnendu; Karri, Ramesh

2016-01-01

A digital microfluidic biochip (DMFB) is an emerging technology that enables miniaturized analysis systems for point-of-care clinical diagnostics, DNA sequencing, and environmental monitoring. A DMFB reduces the rate of sample and reagent consumption, and automates the analysis of assays. In this paper, we provide the first assessment of the security vulnerabilities of DMFBs. We identify result-manipulation attacks on a DMFB that maliciously alter the assay outcomes. Two practical result-manipulation attacks are shown on a DMFB platform performing enzymatic glucose assay on serum. In the first attack, the attacker adjusts the concentration of the glucose sample and thereby modifies the final result. In the second attack, the attacker tampers with the calibration curve of the assay operation. We then identify denial-of-service attacks, where the attacker can disrupt the assay operation by tampering either with the droplet-routing algorithm or with the actuation sequence. We demonstrate these attacks using a digital microfluidic synthesis simulator. The results show that the attacks are easy to implement and hard to detect. Therefore, this work highlights the need for effective protections against malicious modifications in DMFBs.

Managing burn victims of suicide bombing attacks: outcomes, lessons learnt, and changes made from three attacks in Indonesia.

PubMed

Chim, Harvey; Yew, Woon Si; Song, Colin

2007-01-01

Terror attacks in Southeast Asia were almost nonexistent until the 2002 Bali bomb blast, considered the deadliest attack in Indonesian history. Further attacks in 2003 (Jakarta), 2004 (Jakarta), and 2005 (Bali) have turned terrorist attacks into an ever-present reality. The authors reviewed medical charts of victims evacuated to the Singapore General Hospital (SGH) Burns Centre during three suicide attacks involving Bali (2002 and 2005) and the Jakarta Marriott hotel (2003). Problems faced, lessons learnt, and costs incurred are discussed. A burns disaster plan drawing on lessons learnt from these attacks is presented. Thirty-one patients were treated at the SGH Burns Centre in three attacks (2002 Bali attack [n = 15], 2003 Jakarta attack [n = 14], and 2005 Bali attack [n = 2]). For the 2002 Bali attack, median age was 29 years (range 20 to 50 years), median percentage of total burn surface area (TBSA) was 29% (range 5% to 55%), and median abbreviated burn severity index (ABSI) was 6 (range 3 to 10). Eight of 15 patients were admitted to the intensive care unit. For the 2003 Jakarta attack, median age was 35 years (range 24 to 56 years), median percentage of TBSA was 10% (range 2% to 46%), and median ABSI was 4 (range 3 to 9). A large number of patients had other injuries. Problems faced included manpower issues, lack of bed space, shortage of blood products, and lack of cadaver skin. The changing nature of terror attacks mandates continued vigilance and disaster preparedness. The multidimensional burns patient, complicated by other injuries, is likely to become increasingly common. A burns disaster plan with emphasis on effective command, control, and communication as well as organisation of health care personnel following a 'team concept' will do much to ensure that the sudden onset of a crisis situation at an unexpected time does not overwhelm hospital manpower and resources.

Managing burn victims of suicide bombing attacks: outcomes, lessons learnt, and changes made from three attacks in Indonesia

PubMed Central

Chim, Harvey; Yew, Woon Si; Song, Colin

2007-01-01

Introduction Terror attacks in Southeast Asia were almost nonexistent until the 2002 Bali bomb blast, considered the deadliest attack in Indonesian history. Further attacks in 2003 (Jakarta), 2004 (Jakarta), and 2005 (Bali) have turned terrorist attacks into an ever-present reality. Methods The authors reviewed medical charts of victims evacuated to the Singapore General Hospital (SGH) Burns Centre during three suicide attacks involving Bali (2002 and 2005) and the Jakarta Marriott hotel (2003). Problems faced, lessons learnt, and costs incurred are discussed. A burns disaster plan drawing on lessons learnt from these attacks is presented. Results Thirty-one patients were treated at the SGH Burns Centre in three attacks (2002 Bali attack [n = 15], 2003 Jakarta attack [n = 14], and 2005 Bali attack [n = 2]). For the 2002 Bali attack, median age was 29 years (range 20 to 50 years), median percentage of total burn surface area (TBSA) was 29% (range 5% to 55%), and median abbreviated burn severity index (ABSI) was 6 (range 3 to 10). Eight of 15 patients were admitted to the intensive care unit. For the 2003 Jakarta attack, median age was 35 years (range 24 to 56 years), median percentage of TBSA was 10% (range 2% to 46%), and median ABSI was 4 (range 3 to 9). A large number of patients had other injuries. Problems faced included manpower issues, lack of bed space, shortage of blood products, and lack of cadaver skin. Conclusion The changing nature of terror attacks mandates continued vigilance and disaster preparedness. The multidimensional burns patient, complicated by other injuries, is likely to become increasingly common. A burns disaster plan with emphasis on effective command, control, and communication as well as organisation of health care personnel following a 'team concept' will do much to ensure that the sudden onset of a crisis situation at an unexpected time does not overwhelm hospital manpower and resources. PMID:17274813

Robustness analysis of interdependent networks under multiple-attacking strategies

NASA Astrophysics Data System (ADS)

Gao, Yan-Li; Chen, Shi-Ming; Nie, Sen; Ma, Fei; Guan, Jun-Jie

2018-04-01

The robustness of complex networks under attacks largely depends on the structure of a network and the nature of the attacks. Previous research on interdependent networks has focused on two types of initial attack: random attack and degree-based targeted attack. In this paper, a deliberate attack function is proposed, where six kinds of deliberate attacking strategies can be derived by adjusting the tunable parameters. Moreover, the robustness of four types of interdependent networks (BA-BA, ER-ER, BA-ER and ER-BA) with different coupling modes (random, positive and negative correlation) is evaluated under different attacking strategies. Interesting conclusions could be obtained. It can be found that the positive coupling mode can make the vulnerability of the interdependent network to be absolutely dependent on the most vulnerable sub-network under deliberate attacks, whereas random and negative coupling modes make the vulnerability of interdependent network to be mainly dependent on the being attacked sub-network. The robustness of interdependent network will be enhanced with the degree-degree correlation coefficient varying from positive to negative. Therefore, The negative coupling mode is relatively more optimal than others, which can substantially improve the robustness of the ER-ER network and ER-BA network. In terms of the attacking strategies on interdependent networks, the degree information of node is more valuable than the betweenness. In addition, we found a more efficient attacking strategy for each coupled interdependent network and proposed the corresponding protection strategy for suppressing cascading failure. Our results can be very useful for safety design and protection of interdependent networks.

Continuous-variable quantum cryptography is secure against non-Gaussian attacks.

PubMed

Grosshans, Frédéric; Cerf, Nicolas J

2004-01-30

A general study of arbitrary finite-size coherent attacks against continuous-variable quantum cryptographic schemes is presented. It is shown that, if the size of the blocks that can be coherently attacked by an eavesdropper is fixed and much smaller than the key size, then the optimal attack for a given signal-to-noise ratio in the transmission line is an individual Gaussian attack. Consequently, non-Gaussian coherent attacks do not need to be considered in the security analysis of such quantum cryptosystems.

A comparison of the nature and correlates of panic attacks in the context of Panic Disorder and Social Anxiety Disorder.

PubMed

Brown, Lily A; LeBeau, Richard; Liao, Betty; Niles, Andrea N; Glenn, Daniel; Craske, Michelle G

2016-01-30

Panic attacks occurring outside of Panic Disorder are not well-understood despite their inclusion as a diagnostic specifier in the Diagnostic and Statistical Manual for Mental Disorders (DSM-5). This study compares panic attacks in the context of Panic Disorder compared to social anxiety in terms of their symptom frequency, severity, and clinical correlates. Participants (n=404) were interviewed using the Anxiety Disorders Interview Schedule (ADIS-IV-L; Brown et al., 1994), from which we analyzed interviewer ratings of panic attacks and panic attack symptoms, as well as other demographic and clinical characteristics. Panic attacks in the context of Panic Disorder were characterized by a greater number and severity of symptoms compared to panic attacks in the context of Social Anxiety Disorder, and were associated with a history of traumatization, inpatient psychiatric treatment, and benzodiazepine use. Social anxiety panic attacks were associated with reduced physical health concerns. Cognitive panic attack symptoms were more prevalent in Panic Disorder and were associated with a variety of poor clinical correlates. Panic attacks in the context of Panic Disorder are more severe than those in social anxiety, and this may be driven by cognitive disturbances during those attacks. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Heart Attack Recovery FAQs

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... recommendations to make a full recovery. View an animation of a heart attack . Heart Attack Recovery Questions ... Support Network Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

Detecting Distributed SQL Injection Attacks in a Eucalyptus Cloud Environment

NASA Technical Reports Server (NTRS)

Kebert, Alan; Barnejee, Bikramjit; Solano, Juan; Solano, Wanda

2013-01-01

The cloud computing environment offers malicious users the ability to spawn multiple instances of cloud nodes that are similar to virtual machines, except that they can have separate external IP addresses. In this paper we demonstrate how this ability can be exploited by an attacker to distribute his/her attack, in particular SQL injection attacks, in such a way that an intrusion detection system (IDS) could fail to identify this attack. To demonstrate this, we set up a small private cloud, established a vulnerable website in one instance, and placed an IDS within the cloud to monitor the network traffic. We found that an attacker could quite easily defeat the IDS by periodically altering its IP address. To detect such an attacker, we propose to use multi-agent plan recognition, where the multiple source IPs are considered as different agents who are mounting a collaborative attack. We show that such a formulation of this problem yields a more sophisticated approach to detecting SQL injection attacks within a cloud computing environment.

Sensitivity to carbon dioxide in subjects with a single lifetime panic attack: possible clinical "bedside" predictive test for panic disorder after a first attack.

PubMed

Berzak, Elina; Reznik, Mila; Narsia, Oxana; Benjamin, Jonathan

2004-01-01

There is currently no way of knowing whether a patient who has recently had a single panic attack has incipient panic disorder. Sensitivity to carbon dioxide (CO2) is lower in healthy volunteers than in panic disorder patients. If this is also true of people who experience a single lifetime panic attack, it could be used as a prognostic test. Subjects with a single lifetime panic attack and subjects with panic disorder received an inhalation of 35% CO2. Subjects completed the panic symptoms scale (PSS), and also stated whether they considered that they had experienced an attack. None of 14 subjects with a single lifetime panic attack, compared to 7 of 17 subjects with panic disorder (P=.009), had an attack. The PSS also distinguished between the groups. The 35% CO2 challenge warrants further investigation as a predictive test after a first panic attack.

Exploiting Small Leakages in Masks to Turn a Second-Order Attack into a First-Order Attack and Improved Rotating Substitution Box Masking with Linear Code Cosets.

PubMed

DeTrano, Alexander; Karimi, Naghmeh; Karri, Ramesh; Guo, Xiaofei; Carlet, Claude; Guilley, Sylvain

2015-01-01

Masking countermeasures, used to thwart side-channel attacks, have been shown to be vulnerable to mask-extraction attacks. State-of-the-art mask-extraction attacks on the Advanced Encryption Standard (AES) algorithm target S-Box recomputation schemes but have not been applied to scenarios where S-Boxes are precomputed offline. We propose an attack targeting precomputed S-Boxes stored in nonvolatile memory. Our attack targets AES implemented in software protected by a low entropy masking scheme and recovers the masks with 91% success rate. Recovering the secret key requires fewer power traces (in fact, by at least two orders of magnitude) compared to a classical second-order attack. Moreover, we show that this attack remains viable in a noisy environment or with a reduced number of leakage points. Eventually, we specify a method to enhance the countermeasure by selecting a suitable coset of the masks set.

The effect of nursing professional pay structures and pay levels on hospitals' heart attack outcomes.

PubMed

Brown, Mark P

2006-01-01

The effect of nursing professionals (i.e., nurse aid/orderly, licensed practical nurse, registered nurse) pay structures and pay levels on hospitals risk-adjusted heart attack outcomes was determined. Operationalizing hospitals' heart attack outcomes as their thirty-day risk-adjusted mortality rates, a positive curvilinear relation is hypothesized between pay dispersion and hospitals' heart attack outcomes, whereas a direct relation is hypothesized between pay level and hospitals' heart attack outcomes. Pay level is also hypothesized as a moderator of the relation between pay dispersion and hospitals' heart attack outcomes. Using a sample of 138 California hospitals, support is not found for either the curvilinear relation between hospitals' nursing professionals pay dispersion and hospitals' heart attack outcomes, or the direct relation between nursing professionals' pay level and hospitals' heart attack outcomes. Support is found for the moderation hypothesis in which nursing professionals' pay level moderates the relation between hospitals' nursing professionals pay dispersion and hospitals' heart attack outcomes. Implications for practice are discussed in light of the study's results.

Exploiting Small Leakages in Masks to Turn a Second-Order Attack into a First-Order Attack and Improved Rotating Substitution Box Masking with Linear Code Cosets

PubMed Central

DeTrano, Alexander; Karimi, Naghmeh; Karri, Ramesh; Guo, Xiaofei; Carlet, Claude; Guilley, Sylvain

2015-01-01

Masking countermeasures, used to thwart side-channel attacks, have been shown to be vulnerable to mask-extraction attacks. State-of-the-art mask-extraction attacks on the Advanced Encryption Standard (AES) algorithm target S-Box recomputation schemes but have not been applied to scenarios where S-Boxes are precomputed offline. We propose an attack targeting precomputed S-Boxes stored in nonvolatile memory. Our attack targets AES implemented in software protected by a low entropy masking scheme and recovers the masks with 91% success rate. Recovering the secret key requires fewer power traces (in fact, by at least two orders of magnitude) compared to a classical second-order attack. Moreover, we show that this attack remains viable in a noisy environment or with a reduced number of leakage points. Eventually, we specify a method to enhance the countermeasure by selecting a suitable coset of the masks set. PMID:26491717

The Icatibant Outcome Survey: treatment of laryngeal angioedema attacks

PubMed Central

Aberer, Werner; Bouillet, Laurence; Caballero, Teresa; Maurer, Marcus; Fabien, Vincent; Zanichelli, Andrea

2016-01-01

Objective To characterize the management and outcomes of life-threatening laryngeal attacks of hereditary angioedema (HAE) treated with icatibant in the observational Icatibant Outcome Survey (NCT01034969) registry. Methods This retrospective analysis was based on data from patients with HAE type I/II who received healthcare professional-administered or self-administered icatibant to treat laryngeal attacks between September 2008 and May 2013. Results Twenty centers in seven countries contributed data. Overall, 42 patients with HAE experienced 67 icatibant-treated laryngeal attacks. Icatibant was self-administered for 62.3% of attacks (healthcare professional-administered, 37.7%). One icatibant injection was used for 87.9% of attacks, with rescue or concomitant medication used for 9.0%. The median time to treatment was 2.0 h (n=31 attacks) and the median time to resolution was 6.0 h (n=35 attacks). Conclusions This analysis describes successful use of icatibant for the treatment of laryngeal HAE attacks in a real-world setting. PMID:27116379

Heart Attack

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Microvascular Angina

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Using the Domain Name System to Thwart Automated Client-Based Attacks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Curtis R; Shue, Craig A

2011-09-01

On the Internet, attackers can compromise systems owned by other people and then use these systems to launch attacks automatically. When attacks such as phishing or SQL injections are successful, they can have negative consequences including server downtime and the loss of sensitive information. Current methods to prevent such attacks are limited in that they are application-specific, or fail to block attackers. Phishing attempts can be stopped with email filters, but if the attacker manages to successfully bypass these filters, then the user must determine if the email is legitimate or not. Unfortunately, they often are unable to do so.more » Since attackers have a low success rate, they attempt to compensate for it in volume. In order to have this high throughput, attackers take shortcuts and break protocols. We use this knowledge to address these issues by implementing a system that can detect malicious activity and use it to block attacks. If the client fails to follow proper procedure, they can be classified as an attacker. Once an attacker has been discovered, they will be isolated and monitored. This can be accomplished using existing software in Ubuntu Linux applications, along with our custom wrapper application. After running the system and seeing its performance on three popular Web browsers Chromium, Firefox and Internet Explorer as well as two popular email clients, Thunderbird and Evolution, we found that not only is this system conceivable, it is effective and has low overhead.« less

Incidence and impact of dog attacks on guide dogs in the UK.

PubMed

Brooks, A; Moxon, R; England, G C W

2010-06-19

In a retrospective survey, researchers identified 100 incidents of attacks on guide dogs by other dogs. These were reviewed in order to determine the number, severity and impact on the handler and dog, and the characteristics of the aggressors and victims. During the study period there were more than three attacks reported each month, with 61 per cent of the attacks being upon dogs that were in harness and working with an owner or trainer. The majority of the dogs that were attacked were male (62 per cent), and the breeds that were over-represented (relative to their prevalence in the general guide dog population) were the labrador and the golden retriever x flat-coated retriever crossbreed. Most of the attacks occurred in public places between 09.00 and 15.00 and the majority (61 per cent) of the attacking dogs were off the lead at the time of the attack. Thirty-eight per cent of the attacking dogs were of bull breeds, which were over-represented among attackers compared with the proportion of this breed type in the general dog population. Veterinary attention was sought after 41 per cent of the attacks, and in 19 per cent of instances there was injury to the handler or to a member of the public. The attacks were reported to have affected the working performance and behaviour of the victim dog in 45 per cent of the instances, and two dogs had to be subsequently withdrawn from working as guide dogs.

Robustness and structure of complex networks

NASA Astrophysics Data System (ADS)

Shao, Shuai

This dissertation covers the two major parts of my PhD research on statistical physics and complex networks: i) modeling a new type of attack -- localized attack, and investigating robustness of complex networks under this type of attack; ii) discovering the clustering structure in complex networks and its influence on the robustness of coupled networks. Complex networks appear in every aspect of our daily life and are widely studied in Physics, Mathematics, Biology, and Computer Science. One important property of complex networks is their robustness under attacks, which depends crucially on the nature of attacks and the structure of the networks themselves. Previous studies have focused on two types of attack: random attack and targeted attack, which, however, are insufficient to describe many real-world damages. Here we propose a new type of attack -- localized attack, and study the robustness of complex networks under this type of attack, both analytically and via simulation. On the other hand, we also study the clustering structure in the network, and its influence on the robustness of a complex network system. In the first part, we propose a theoretical framework to study the robustness of complex networks under localized attack based on percolation theory and generating function method. We investigate the percolation properties, including the critical threshold of the phase transition pc and the size of the giant component Pinfinity. We compare localized attack with random attack and find that while random regular (RR) networks are more robust against localized attack, Erdoḧs-Renyi (ER) networks are equally robust under both types of attacks. As for scale-free (SF) networks, their robustness depends crucially on the degree exponent lambda. The simulation results show perfect agreement with theoretical predictions. We also test our model on two real-world networks: a peer-to-peer computer network and an airline network, and find that the real-world networks are much more vulnerable to localized attack compared with random attack. In the second part, we extend the tree-like generating function method to incorporating clustering structure in complex networks. We study the robustness of a complex network system, especially a network of networks (NON) with clustering structure in each network. We find that the system becomes less robust as we increase the clustering coefficient of each network. For a partially dependent network system, we also find that the influence of the clustering coefficient on network robustness decreases as we decrease the coupling strength, and the critical coupling strength qc, at which the first-order phase transition changes to second-order, increases as we increase the clustering coefficient.

Phenomenology of panic attacks: a descriptive study of panic disorder patients' self-reports.

PubMed

Aronson, T A; Logue, C M

1988-01-01

The phenomenology of panic disorder and panic attacks was systematically assessed in 46 consecutive patients. The results suggest that DSM-III criteria include several symptoms that are not frequently present during a panic attack and that DSM-III's characterization of a panic attack is imprecise and misleading. Panic attacks were found to vary in intensity, frequency, spontaneity, and associated symptoms. A panic attack typically presents as a unified symptom complex of psychic anxiety and multiple somatic symptoms in multiple body systems. It occurs in a crescendolike pattern, is self-limited, and often leaves the subject weak or shaken. The temporal course as much as the symptomatic presentation defines a panic attack.

Finite Energy and Bounded Attacks on Control System Sensor Signals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Djouadi, Seddik M; Melin, Alexander M; Ferragut, Erik M

Control system networks are increasingly being connected to enterprise level networks. These connections leave critical industrial controls systems vulnerable to cyber-attacks. Most of the effort in protecting these cyber-physical systems (CPS) has been in securing the networks using information security techniques and protection and reliability concerns at the control system level against random hardware and software failures. However, besides these failures the inability of information security techniques to protect against all intrusions means that the control system must be resilient to various signal attacks for which new analysis and detection methods need to be developed. In this paper, sensor signalmore » attacks are analyzed for observer-based controlled systems. The threat surface for sensor signal attacks is subdivided into denial of service, finite energy, and bounded attacks. In particular, the error signals between states of attack free systems and systems subject to these attacks are quantified. Optimal sensor and actuator signal attacks for the finite and infinite horizon linear quadratic (LQ) control in terms of maximizing the corresponding cost functions are computed. The closed-loop system under optimal signal attacks are provided. Illustrative numerical examples are provided together with an application to a power network with distributed LQ controllers.« less

Multi-Layer Approach for the Detection of Selective Forwarding Attacks

PubMed Central

Alajmi, Naser; Elleithy, Khaled

2015-01-01

Security breaches are a major threat in wireless sensor networks (WSNs). WSNs are increasingly used due to their broad range of important applications in both military and civilian domains. WSNs are prone to several types of security attacks. Sensor nodes have limited capacities and are often deployed in dangerous locations; therefore, they are vulnerable to different types of attacks, including wormhole, sinkhole, and selective forwarding attacks. Security attacks are classified as data traffic and routing attacks. These security attacks could affect the most significant applications of WSNs, namely, military surveillance, traffic monitoring, and healthcare. Therefore, there are different approaches to detecting security attacks on the network layer in WSNs. Reliability, energy efficiency, and scalability are strong constraints on sensor nodes that affect the security of WSNs. Because sensor nodes have limited capabilities in most of these areas, selective forwarding attacks cannot be easily detected in networks. In this paper, we propose an approach to selective forwarding detection (SFD). The approach has three layers: MAC pool IDs, rule-based processing, and anomaly detection. It maintains the safety of data transmission between a source node and base station while detecting selective forwarding attacks. Furthermore, the approach is reliable, energy efficient, and scalable. PMID:26610499

Cougar attacks on children: injury patterns and treatment.

PubMed

Kadesky, K M; Manarey, C; Blair, G K; Murphy, J J; Verchere, C; Atkinson, K

1998-06-01

Cougar attacks on humans appear to be on the rise. A review of all attacks on children was performed to determine the method of attack and injury patterns so that a treatment regimen as well as possible preventative measures could be determined. A review of all attacks, including attacks on children, was performed, including three recent attacks treated at our institution. Situation, adult supervision, patient age, injuries recorded, survival, and mode of attack, if known, were reviewed. There were 50 documented attacks on children with a 25% fatality rate. Most children were not alone at the time of the attack (92%), and in many instances adult supervision was present or nearby. Severe head and neck lacerations along with puncture wounds were the most common injury. Examples of typical cervical injuries include a nonfatal vertebral artery injury, phrenic nerve injury, a fatal internal carotid artery injury, and a fatal cervical spine injury. The cougar was rabid in two cases. Pasteurella resulted in late infections in two patients. Based on the pattern of injuries, the authors recommend aggressive evaluation for occult cervical injuries as well as surgical debridement. Antibiotics should cover oropharyngeal flora including Pasteurella multocida. Rabies prophylaxis is indicated. Adult supervision in wilderness areas is not necessarily protective.

Multi-Layer Approach for the Detection of Selective Forwarding Attacks.

PubMed

Alajmi, Naser; Elleithy, Khaled

2015-11-19

Security breaches are a major threat in wireless sensor networks (WSNs). WSNs are increasingly used due to their broad range of important applications in both military and civilian domains. WSNs are prone to several types of security attacks. Sensor nodes have limited capacities and are often deployed in dangerous locations; therefore, they are vulnerable to different types of attacks, including wormhole, sinkhole, and selective forwarding attacks. Security attacks are classified as data traffic and routing attacks. These security attacks could affect the most significant applications of WSNs, namely, military surveillance, traffic monitoring, and healthcare. Therefore, there are different approaches to detecting security attacks on the network layer in WSNs. Reliability, energy efficiency, and scalability are strong constraints on sensor nodes that affect the security of WSNs. Because sensor nodes have limited capabilities in most of these areas, selective forwarding attacks cannot be easily detected in networks. In this paper, we propose an approach to selective forwarding detection (SFD). The approach has three layers: MAC pool IDs, rule-based processing, and anomaly detection. It maintains the safety of data transmission between a source node and base station while detecting selective forwarding attacks. Furthermore, the approach is reliable, energy efficient, and scalable.

Incidence and impact of dog attacks on guide dogs in the UK: an update.

PubMed

Moxon, R; Whiteside, H; England, G C W

2016-04-09

Data on dog attacks on Guide Dogs' stock were reviewed to investigate the characteristics of the attacks. An average of 11.2 attacks occurred each month. Nearly all of the attacks occurred in public areas, 68.4 per cent of victim dogs were qualified guide dogs and 55.5 per cent of victim dogs were working in harness when they were attacked. Guide Dogs' stock were injured in 43.2 per cent of attacks and veterinary costs for attacks were estimated at £34,514.30. Over 40 per cent of qualified guide dogs' working ability was affected and >20 per cent of qualified guide dogs required some time off from working after a dog attack. Twenty dogs were permanently withdrawn from the Guide Dogs' programme as a result of dog attacks, 13 of which were qualified and working with guide dog owners at the time of the withdrawal; this resulted in a financial cost of >£600,000 to the charity. More importantly perhaps, temporary and permanent withdrawals have a significant impact upon the mobility and independence of guide dog owners and in many cases significantly impacted their emotional well-being. British Veterinary Association.

Childhood internalizing and externalizing problems predict the onset of clinical panic attacks over adolescence: the TRAILS study.

PubMed

Mathyssek, Christina M; Olino, Thomas M; Verhulst, Frank C; van Oort, Floor V A

2012-01-01

Panic attacks are a source of individual suffering and are an independent risk factor for later psychopathology. However, much less is known about risk factors for the development of panic attacks, particularly during adolescence when the incidence of panic attacks increases dramatically. We examined whether internalizing and externalizing problems in childhood predict the onset of panic attacks in adolescence. This study is part of the TRacking Adolescents' Individual Lives Survey (TRAILS), a Dutch longitudinal population cohort study (N = 1,584). Internalizing and Externalizing Problems were collected using the Youth Self-Report (YSR) and the parent-report Child Behavior Checklist (CBCL) at baseline (age 10-12). At age 18-20, DSM-IV defined panic attacks since baseline were assessed with the Composite International Diagnostic Interview (CIDI). We investigated whether early adolescent Internalizing and Externalizing Problems predicted panic attacks between ages 10-20 years, using survival analysis in univariate and multivariate models. There were N = 314 (19.8%) cases who experienced at least one DSM-IV defined panic attack during adolescence and N = 18 (1.2%) who developed panic disorder during adolescence. In univariate analyses, CBCL Total Problems, Internalizing Problems and three of the eight syndrome scales predicted panic attack onset, while on the YSR all broad-band problem scales and each narrow-band syndrome scale predicted panic attack onset. In multivariate analyses, CBCL Social Problems (HR 1.19, p<.05), and YSR Thought Problems (HR 1.15, p<.05) and Social Problems (HR 1.26, p<.01) predicted panic attack onset. Risk indicators of panic attack include the wide range of internalizing and externalizing problems. Yet, when adjusted for co-occurring problem behaviors, Social Problems were the most consistent risk factor for panic attack onsets in adolescence.

Countermeasures for unintentional and intentional video watermarking attacks

NASA Astrophysics Data System (ADS)

Deguillaume, Frederic; Csurka, Gabriela; Pun, Thierry

2000-05-01

These last years, the rapidly growing digital multimedia market has revealed an urgent need for effective copyright protection mechanisms. Therefore, digital audio, image and video watermarking has recently become a very active area of research, as a solution to this problem. Many important issues have been pointed out, one of them being the robustness to non-intentional and intentional attacks. This paper studies some attacks and proposes countermeasures applied to videos. General attacks are lossy copying/transcoding such as MPEG compression and digital/analog (D/A) conversion, changes of frame-rate, changes of display format, and geometrical distortions. More specific attacks are sequence edition, and statistical attacks such as averaging or collusion. Averaging attack consists of averaging locally consecutive frames to cancel the watermark. This attack works well for schemes which embed random independent marks into frames. In the collusion attack the watermark is estimated from single frames (based on image denoising), and averaged over different scenes for better accuracy. The estimated watermark is then subtracted from each frame. Collusion requires that the same mark is embedded into all frames. The proposed countermeasures first ensures robustness to general attacks by spread spectrum encoding in the frequency domain and by the use of an additional template. Secondly, a Bayesian criterion, evaluating the probability of a correctly decoded watermark, is used for rejection of outliers, and to implement an algorithm against statistical attacks. The idea is to embed randomly chosen marks among a finite set of marks, into subsequences of videos which are long enough to resist averaging attacks, but short enough to avoid collusion attacks. The Bayesian criterion is needed to select the correct mark at the decoding step. Finally, the paper presents experimental results showing the robustness of the proposed method.

Unstable Angina

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... Women This content was last reviewed July 2015. Heart Attack • Home • About Heart Attacks Acute Coronary Syndrome (ACS) ... Recovery FAQs • Heart Attack Tools & Resources • Support Network Heart Attack Tools & Resources My Cardiac Coach What Is a ...

Acute Coronary Syndrome

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... angina? This content was last reviewed July 2015. Heart Attack • Home • About Heart Attacks Acute Coronary Syndrome (ACS) ... Recovery FAQs • Heart Attack Tools & Resources • Support Network Heart Attack Tools & Resources My Cardiac Coach What Is a ...

Analysis of characteristics associated with reinjection of icatibant: Results from the icatibant outcome survey.

PubMed

Longhurst, Hilary J; Aberer, Werner; Bouillet, Laurence; Caballero, Teresa; Fabien, Vincent; Zanichelli, Andrea; Maurer, Marcus

2015-01-01

Phase 3 icatibant trials showed that most hereditary angioedema (HAE) (C1 inhibitor deficiency) acute attacks were treated successfully with one injection of icatibant, a selective bradykinin B2 receptor antagonist. We conducted a post hoc analysis of icatibant reinjection for HAE type I and II attacks in a real-world setting by using data from the Icatibant Outcome Survey, an ongoing observational study that monitors the safety and effectiveness of icatibant treatment. Descriptive retrospective analyses of icatibant reinjection were performed on Icatibant Outcome Survey data (February 2008 to December 2012). New attacks were defined as the onset of new symptoms after full resolution of the previous attack. Potential associations between the patient and attack characteristics and reinjection were explored by using logistic regression analysis. Icatibant was administered for 652 attacks in 170 patients with HAE type I or II. Most attacks (89.1%) were treated with a single icatibant injection. For attacks that required two or three injections, the second injection was given a median of 11.0 hours after the first injection, with 90.4% of second injections administered ≥6 hours after the first injection. Time to resolution and attack duration were significantly longer for two or three injections versus one icatibant injection (p < 0.0001 and p < 0.05, respectively). Multivariate logistic regression analysis identified sex, attack severity, and laryngeal attacks as significantly correlated with reinjection (all p ≤ 0.05). These factors did not remain predictors for reinjection when two outlier patients with distinct patterns of icatibant use were excluded. In this real-world setting, most HAE attacks resolved with one icatibant injection. There was no distinct profile for patients or attacks that required reinjection when outliers with substantially different patterns of use were excluded. Because new attacks were not distinguished from the recurrence of symptoms, reinjection rates may be slightly higher than shown here. Clinical trial identifier: NCT01034969.

Enhanced diffie-hellman algorithm for reliable key exchange

NASA Astrophysics Data System (ADS)

Aryan; Kumar, Chaithanya; Vincent, P. M. Durai Raj

2017-11-01

The Diffie -Hellman is one of the first public-key procedure and is a certain way of exchanging the cryptographic keys securely. This concept was introduced by Ralph Markel and it is named after Whitfield Diffie and Martin Hellman. Sender and Receiver make a common secret key in Diffie-Hellman algorithm and then they start communicating with each other over the public channel which is known to everyone. A number of internet services are secured by Diffie -Hellman. In Public key cryptosystem, the sender has to trust while receiving the public key of the receiver and vice-versa and this is the challenge of public key cryptosystem. Man-in-the-Middle attack is very much possible on the existing Diffie-Hellman algorithm. In man-in-the-middle attack, the attacker exists in the public channel, the attacker receives the public key of both sender and receiver and sends public keys to sender and receiver which is generated by his own. This is how man-in-the-middle attack is possible on Diffie-Hellman algorithm. Denial of service attack is another attack which is found common on Diffie-Hellman. In this attack, the attacker tries to stop the communication happening between sender and receiver and attacker can do this by deleting messages or by confusing the parties with miscommunication. Some more attacks like Insider attack, Outsider attack, etc are possible on Diffie-Hellman. To reduce the possibility of attacks on Diffie-Hellman algorithm, we have enhanced the Diffie-Hellman algorithm to a next level. In this paper, we are extending the Diffie -Hellman algorithm by using the concept of the Diffie -Hellman algorithm to get a stronger secret key and that secret key is further exchanged between the sender and the receiver so that for each message, a new secret shared key would be generated. The second secret key will be generated by taking primitive root of the first secret key.

The panic attack-posttraumatic stress disorder model: applicability to orthostatic panic among Cambodian refugees.

PubMed

Hinton, Devon E; Hofmann, Stefan G; Pitman, Roger K; Pollack, Mark H; Barlow, David H

2008-01-01

This article examines the ability of the panic attack-posttraumatic stress disorder (PTSD) model to predict how panic attacks are generated and how panic attacks worsen PTSD. The article does so by determining the validity of the panic attack-PTSD model in respect to one type of panic attack among traumatized Cambodian refugees: orthostatic panic (OP) attacks (i.e. panic attacks generated by moving from lying or sitting to standing). Among Cambodian refugees attending a psychiatric clinic, the authors conducted two studies to explore the validity of the panic attack-PTSD model as applied to OP patients (i.e. patients with at least one episode of OP in the previous month). In Study 1, the panic attack-PTSD model accurately indicated how OP is seemingly generated: among OP patients (N = 58), orthostasis-associated flashbacks and catastrophic cognitions predicted OP severity beyond a measure of anxious-depressive distress (Symptom Checklist-90-R subscales), and OP severity significantly mediated the effect of anxious-depressive distress on Clinician-Administered PTSD Scale severity. In Study 2, as predicted by the panic attack-PTSD model, OP had a mediational role in respect to the effect of treatment on PTSD severity: among Cambodian refugees with PTSD and comorbid OP who participated in a cognitive behavioural therapy study (N = 56), improvement in PTSD severity was partially mediated by improvement in OP severity.

Epileptic negative drop attacks in atypical benign partial epilepsy: a neurophysiological study.

PubMed

Hirano, Yoshiko; Oguni, Hirokazu; Osawa, Makiko

2009-03-01

We conducted a computer-assisted polygraphic analysis of drop attacks in a child with atypical benign partial epilepsy (ABPE) to investigate neurophysiological characteristics. The patient was a six-year two-month-old girl, who had started to have focal motor seizures, later combined with daily epileptic negative myoclonus (ENM) and drop attacks, causing multiple injuries. We studied episodes of ENM and drop attacks using video-polygraphic and computer-assisted back-averaging analysis. A total of 12 ENM episodes, seven involving the left arm (ENMlt) and five involving both arms (ENMbil), and five drop attacks were captured for analysis. All episodes were time-locked to spike-and-wave complexes (SWC) arising from both centro-temporo-parietal (CTP) areas. The latency between the onset of SWC and ENMlt, ENMbil, and drop attacks reached 68 ms, 42 ms, and 8 ms, respectively. The height of the spike as well as the slow-wave component of SWC for drop attacks were significantly larger than that for both ENMlt and ENMbil (p < 0.05). Drop attacks were considered to be epileptic negative myoclonus involving not only upper proximal but also axial muscles, causing the body to fall. Thus, drop attacks in ABPE are considered to be epileptic negative drop attacks arising from bilateral CTP foci and differ from drop attacks of a generalized origin seen in Lennox-Gastaut syndrome and myoclonic-astatic epilepsy.

Seven Deadliest Network Attacks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prowell, Stacy J; Borkin, Michael; Kraus, Robert

2010-05-01

Do you need to keep up with the latest hacks, attacks, and exploits effecting networks? Then you need "Seven Deadliest Network Attacks". This book pinpoints the most dangerous hacks and exploits specific to networks, laying out the anatomy of these attacks including how to make your system more secure. You will discover the best ways to defend against these vicious hacks with step-by-step instruction and learn techniques to make your computer and network impenetrable. Attacks detailed in this book include: Denial of Service; War Dialing; Penetration 'Testing'; Protocol Tunneling; Spanning Tree Attacks; Man-in-the-Middle; and, Password Replay. Knowledge is power, findmore » out about the most dominant attacks currently waging war on computers and networks globally. Discover the best ways to defend against these vicious attacks; step-by-step instruction shows you how. Institute countermeasures, don't be caught defenseless again, learn techniques to make your computer and network impenetrable.« less

Dynamic defense and network randomization for computer systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chavez, Adrian R.; Stout, William M. S.; Hamlet, Jason R.

The various technologies presented herein relate to determining a network attack is taking place, and further to adjust one or more network parameters such that the network becomes dynamically configured. A plurality of machine learning algorithms are configured to recognize an active attack pattern. Notification of the attack can be generated, and knowledge gained from the detected attack pattern can be utilized to improve the knowledge of the algorithms to detect a subsequent attack vector(s). Further, network settings and application communications can be dynamically randomized, wherein artificial diversity converts control systems into moving targets that help mitigate the early reconnaissancemore » stages of an attack. An attack(s) based upon a known static address(es) of a critical infrastructure network device(s) can be mitigated by the dynamic randomization. Network parameters that can be randomized include IP addresses, application port numbers, paths data packets navigate through the network, application randomization, etc.« less

Automatic Inference of Cryptographic Key Length Based on Analysis of Proof Tightness

DTIC Science & Technology

2016-06-01

within an attack tree structure, then expand attack tree methodology to include cryptographic reductions. We then provide the algorithms for...maintaining and automatically reasoning about these expanded attack trees . We provide a software tool that utilizes machine-readable proof and attack metadata...and the attack tree methodology to provide rapid and precise answers regarding security parameters and effective security. This eliminates the need

Cyber Signal/Noise Characteristics and Sensor Models for Early Cyber Indications and Warning

DTIC Science & Technology

2005-09-01

investigating and simulating attack scenarios. The sensors are, in effect , mathematical functions. These functions range from simple functions of...172 8.1.2 Examine each attack scenario or case to derive the cause- effect network for the attack scenario...threat profiles............................ 174 8.1.4 Develop attack profiles by enlarging the cause- effect network of each attack scenario with

Attack Coverage in High-Level Men’s Volleyball: Organization on the Edge of Chaos?

PubMed Central

Laporta, Lorenzo; Nikolaidis, Pantelis; Thomas, Luke; Afonso, José

2015-01-01

Change is pervasive, but emerging patterns are occasionally detectable through analysis of systemic behaviors. Match analysis uses these patterns in order to reduce the degree of improvisation and to optimize the training process. However, it is possible that certain game phases elude systematic patterning. In this vein, our aim was to analyze the case of attack coverage in men’s volleyball, as we suspected it would elude systematic patterning and has received negligible attention in scientific research. We analyzed the occurrence of attack coverage in 4544 plays of the 2011 Volleyball World League. A Chi-square test with residual adjusted values was applied to explore significant associations between variables. A Monte Carlo correction was applied, as some cells had n<5. Effect sizes were determined using Cramer’s V. Overall, attack coverage occurred in 3.89% of ball possessions, and 23 distinct structures emerged. These structures lacked significant associations with the game complex, setting zone, and effect of attack coverage. Conversely, attack coverage structures showed significant associations with the attack zone and tempo, with very strong effect sizes (V=0.472 and V=0.521, respectively). As certain attack zones are deeply associated with attack tempo, it is apparent that quicker attack plays affect attack coverage structuring, promoting the formation of less complex structures. Ultimately, attack coverage structures seem to depend on momentary constraints, thereby rendering rigid systematization impracticable. Still, we contended that a principle-based approach might be suitable. This invites researchers to rethink how to interpret game regularities. PMID:26557208

Cued Panic Attacks in Body Dysmorphic Disorder

PubMed Central

Phillips, Katharine A.; Menard, William; Bjornsson, Andri S.

2013-01-01

Background Body dysmorphic disorder (BDD) is a common and often severe disorder. Clinical observations suggest that panic attacks triggered by BDD symptoms may be common. However, to our knowledge, no study has examined such panic attacks in BDD. We investigated the prevalence, clinical features, and correlates of BDD-triggered panic attacks in individuals with this disorder. Methods Panic attacks and other variables were assessed using reliable and valid measures in 76 individuals with lifetime DSM-IV BDD. Results 28.9% (95% CI, 18.5%–39.4%) of participants reported lifetime panic attacks triggered by BDD symptoms. The most common triggers of such attacks were feeling that others were looking at or scrutinizing the perceived appearance defects (61.9%), looking in the mirror at perceived defects (38.1%), and being in bright light where perceived defects would be more visible (23.8%). The most common panic attack symptoms were palpitations (86.4%), sweating (66.7%), shortness of breath (63.6%), trembling or shaking (63.6%), and fear of losing control or going crazy (63.6%). Compared to participants without such panic attacks, those with BDD-triggered panic attacks had more severe lifetime BDD, social anxiety, and depressive symptoms, as well as poorer functioning and quality of life on a number of measures. They were also less likely to be employed and more likely to have been psychiatrically hospitalized and to have had suicidal ideation due to BDD. Conclusions Panic attacks triggered by BDD-related situations appear common in individuals with this disorder. BDD-triggered panic attacks were associated with greater symptom severity and morbidity. PMID:23653076

Randomness determines practical security of BB84 quantum key distribution.

PubMed

Li, Hong-Wei; Yin, Zhen-Qiang; Wang, Shuang; Qian, Yong-Jun; Chen, Wei; Guo, Guang-Can; Han, Zheng-Fu

2015-11-10

Unconditional security of the BB84 quantum key distribution protocol has been proved by exploiting the fundamental laws of quantum mechanics, but the practical quantum key distribution system maybe hacked by considering the imperfect state preparation and measurement respectively. Until now, different attacking schemes have been proposed by utilizing imperfect devices, but the general security analysis model against all of the practical attacking schemes has not been proposed. Here, we demonstrate that the general practical attacking schemes can be divided into the Trojan horse attack, strong randomness attack and weak randomness attack respectively. We prove security of BB84 protocol under randomness attacking models, and these results can be applied to guarantee the security of the practical quantum key distribution system.

Attacks by jaguars (Panthera onca) on humans in central Brazil: report of three cases, with observation of a death.

PubMed

Neto, Manoel Francisco Campos; Garrone Neto, Domingos; Haddad, Vidal

2011-06-01

Conflicts between humans and big cats have been known for centuries throughout the world, but have intensified in recent decades. Recently, attacks by Panthera onca on humans in Brazil have been brought to the forefront through exposure in the press and because of the severity of the attacks. We report 3 cases of patients attacked by jaguars in provoked and predatory situations. Two patients survived the attacks and one died. Attack mechanisms and lesions in victims are discussed. The attacks demonstrate a real risk of accidents from jaguars in certain regions, such as the Pantanal and the Amazon. Copyright © 2011 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Randomness determines practical security of BB84 quantum key distribution

PubMed Central

Li, Hong-Wei; Yin, Zhen-Qiang; Wang, Shuang; Qian, Yong-Jun; Chen, Wei; Guo, Guang-Can; Han, Zheng-Fu

2015-01-01

Unconditional security of the BB84 quantum key distribution protocol has been proved by exploiting the fundamental laws of quantum mechanics, but the practical quantum key distribution system maybe hacked by considering the imperfect state preparation and measurement respectively. Until now, different attacking schemes have been proposed by utilizing imperfect devices, but the general security analysis model against all of the practical attacking schemes has not been proposed. Here, we demonstrate that the general practical attacking schemes can be divided into the Trojan horse attack, strong randomness attack and weak randomness attack respectively. We prove security of BB84 protocol under randomness attacking models, and these results can be applied to guarantee the security of the practical quantum key distribution system. PMID:26552359

Randomness determines practical security of BB84 quantum key distribution

NASA Astrophysics Data System (ADS)

Li, Hong-Wei; Yin, Zhen-Qiang; Wang, Shuang; Qian, Yong-Jun; Chen, Wei; Guo, Guang-Can; Han, Zheng-Fu

2015-11-01

Unconditional security of the BB84 quantum key distribution protocol has been proved by exploiting the fundamental laws of quantum mechanics, but the practical quantum key distribution system maybe hacked by considering the imperfect state preparation and measurement respectively. Until now, different attacking schemes have been proposed by utilizing imperfect devices, but the general security analysis model against all of the practical attacking schemes has not been proposed. Here, we demonstrate that the general practical attacking schemes can be divided into the Trojan horse attack, strong randomness attack and weak randomness attack respectively. We prove security of BB84 protocol under randomness attacking models, and these results can be applied to guarantee the security of the practical quantum key distribution system.

A Novel Network Attack Audit System based on Multi-Agent Technology

NASA Astrophysics Data System (ADS)

Jianping, Wang; Min, Chen; Xianwen, Wu

A network attack audit system which includes network attack audit Agent, host audit Agent and management control center audit Agent is proposed. And the improved multi-agent technology is carried out in the network attack audit Agent which has achieved satisfactory audit results. The audit system in terms of network attack is just in-depth, and with the function improvement of network attack audit Agent, different attack will be better analyzed and audit. In addition, the management control center Agent should manage and analyze audit results from AA (or HA) and audit data on time. And the history files of network packets and host log data should also be audit to find deeper violations that cannot be found in real time.

Extended Password Recovery Attacks against APOP, SIP, and Digest Authentication

NASA Astrophysics Data System (ADS)

Sasaki, Yu; Wang, Lei; Ohta, Kazuo; Kunihiro, Noboru

In this paper, we propose password recovery attacks against challenge-response authentication protocols. Our attacks use a message difference for a MD5 collision attack proposed in IEICE 2008. First, we show how to efficiently find a message pair that collides with the above message difference. Second, we show that a password used in authenticated post office protocol (APOP) can be recovered practically. We also show that the password recovery attack can be applied to a session initiation protocol (SIP) and digest authentication. Our attack can recover up to the first 31 password characters in a short time and up to the first 60 characters faster than the naive search method. We have implemented our attack and confirmed that 31 characters can be successfully recovered.

Percolation of localized attack on complex networks

NASA Astrophysics Data System (ADS)

Shao, Shuai; Huang, Xuqing; Stanley, H. Eugene; Havlin, Shlomo

2015-02-01

The robustness of complex networks against node failure and malicious attack has been of interest for decades, while most of the research has focused on random attack or hub-targeted attack. In many real-world scenarios, however, attacks are neither random nor hub-targeted, but localized, where a group of neighboring nodes in a network are attacked and fail. In this paper we develop a percolation framework to analytically and numerically study the robustness of complex networks against such localized attack. In particular, we investigate this robustness in Erdős-Rényi networks, random-regular networks, and scale-free networks. Our results provide insight into how to better protect networks, enhance cybersecurity, and facilitate the design of more robust infrastructures.

Face liveness detection for face recognition based on cardiac features of skin color image

NASA Astrophysics Data System (ADS)

Suh, Kun Ha; Lee, Eui Chul

2016-07-01

With the growth of biometric technology, spoofing attacks have been emerged a threat to the security of the system. Main spoofing scenarios in the face recognition system include the printing attack, replay attack, and 3D mask attack. To prevent such attacks, techniques that evaluating liveness of the biometric data can be considered as a solution. In this paper, a novel face liveness detection method based on cardiac signal extracted from face is presented. The key point of proposed method is that the cardiac characteristic is detected in live faces but not detected in non-live faces. Experimental results showed that the proposed method can be effective way for determining printing attack or 3D mask attack.

Hereditary Angioedema Attacks: Local Swelling at Multiple Sites.

PubMed

Hofman, Zonne L M; Relan, Anurag; Hack, C Erik

2016-02-01

Hereditary angioedema (HAE) patients experience recurrent local swelling in various parts of the body including painful swelling of the intestine and life-threatening laryngeal oedema. Most HAE literature is about attacks located in one anatomical site, though it is mentioned that HAE attacks may also involve multiple anatomical sites simultaneously. A detailed description of such multi-location attacks is currently lacking. This study investigated the occurrence, severity and clinical course of HAE attacks with multiple anatomical locations. HAE patients included in a clinical database of recombinant human C1-inhibitor (rhC1INH) studies were evaluated. Visual analog scale scores filled out by the patients for various symptoms at various locations and investigator symptoms scores during the attack were analysed. Data of 219 eligible attacks in 119 patients was analysed. Thirty-three patients (28%) had symptoms at multiple locations in anatomically unrelated regions at the same time during their first attack. Up to five simultaneously affected locations were reported. The observation that severe HAE attacks often affect multiple sites in the body suggests that HAE symptoms result from a systemic rather than from a local process as is currently believed.

Heart Attack or Sudden Cardiac Arrest: How Are They Different?

MedlinePlus

... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Heart Attack or Sudden Cardiac Arrest: How Are They Different? ... and procedures related to heart disease and stroke. Heart Attack • Home • About Heart Attacks Acute Coronary Syndrome (ACS) ...

Risk Management

DTIC Science & Technology

2011-06-02

actively attack the risks, they will actively attack you.” -Tom Gib Why do Risk Management? 8 “The first step in the risk management process is to...opportunities to manage and improve our chances of success. - Roger Vanscoy “If you do not actively attack the risks, they will actively attack ...our risks provides opportunities to manage and improve our chances of success. - Roger Vanscoy “If you do not actively attack the risks, they will

Experimental implementation of non-Gaussian attacks on a continuous-variable quantum-key-distribution system.

PubMed

Lodewyck, Jérôme; Debuisschert, Thierry; García-Patrón, Raúl; Tualle-Brouri, Rosa; Cerf, Nicolas J; Grangier, Philippe

2007-01-19

An intercept-resend attack on a continuous-variable quantum-key-distribution protocol is investigated experimentally. By varying the interception fraction, one can implement a family of attacks where the eavesdropper totally controls the channel parameters. In general, such attacks add excess noise in the channel, and may also result in non-Gaussian output distributions. We implement and characterize the measurements needed to detect these attacks, and evaluate experimentally the information rates available to the legitimate users and the eavesdropper. The results are consistent with the optimality of Gaussian attacks resulting from the security proofs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

John Homer; Ashok Varikuti; Xinming Ou

Various tools exist to analyze enterprise network systems and to produce attack graphs detailing how attackers might penetrate into the system. These attack graphs, however, are often complex and difficult to comprehend fully, and a human user may find it problematic to reach appropriate configuration decisions. This paper presents methodologies that can 1) automatically identify portions of an attack graph that do not help a user to understand the core security problems and so can be trimmed, and 2) automatically group similar attack steps as virtual nodes in a model of the network topology, to immediately increase the understandability ofmore » the data. We believe both methods are important steps toward improving visualization of attack graphs to make them more useful in configuration management for large enterprise networks. We implemented our methods using one of the existing attack-graph toolkits. Initial experimentation shows that the proposed approaches can 1) significantly reduce the complexity of attack graphs by trimming a large portion of the graph that is not needed for a user to understand the security problem, and 2) significantly increase the accessibility and understandability of the data presented in the attack graph by clearly showing, within a generated visualization of the network topology, the number and type of potential attacks to which each host is exposed.« less

On resilience studies of system detection and recovery techniques against stealthy insider attacks

NASA Astrophysics Data System (ADS)

Wei, Sixiao; Zhang, Hanlin; Chen, Genshe; Shen, Dan; Yu, Wei; Pham, Khanh D.; Blasch, Erik P.; Cruz, Jose B.

2016-05-01

With the explosive growth of network technologies, insider attacks have become a major concern to business operations that largely rely on computer networks. To better detect insider attacks that marginally manipulate network traffic over time, and to recover the system from attacks, in this paper we implement a temporal-based detection scheme using the sequential hypothesis testing technique. Two hypothetical states are considered: the null hypothesis that the collected information is from benign historical traffic and the alternative hypothesis that the network is under attack. The objective of such a detection scheme is to recognize the change within the shortest time by comparing the two defined hypotheses. In addition, once the attack is detected, a server migration-based system recovery scheme can be triggered to recover the system to the state prior to the attack. To understand mitigation of insider attacks, a multi-functional web display of the detection analysis was developed for real-time analytic. Experiments using real-world traffic traces evaluate the effectiveness of Detection System and Recovery (DeSyAR) scheme. The evaluation data validates the detection scheme based on sequential hypothesis testing and the server migration-based system recovery scheme can perform well in effectively detecting insider attacks and recovering the system under attack.

Impact of Tumarkin attacks on complaints and work ability in Ménière's disease.

PubMed

Pyykkö, Ilmari; Manchaiah, Vinaya; Zou, Jing; Levo, Hilla; Kentala, Erna

2018-05-22

The purpose of the present study was to characterize the occurrence of Tumarkin attacks in patients with Ménière'sdisease (MD), and to study its association with reported complaints, severity of consequences, and also self-reported work ability. The study used a cross-sectional design. Data obtained from the Finnish Ménière Federation using an electronic survey was analyzed. 602 people with MD responded to the survey (62% response rate) with a mean age of 56.7 years and a mean duration of the disease 12.4 years. 49% of the respondents experienced Tumarkin attacks, which lasted for a few seconds to a few minutes. There were significant differences in complaints reported by MD patients with and without Tumarkin attacks. Respondents with Tumarkin attacks experienced various consequences, including tripping, falls, fear, anxiety, problems in dyadic life, and even transient loss of consciousness. Respondents with Tumarkin attacks had more frequently applied for pension than those not having Tumarkin attacks. On an average, respondents with Tumarkin attacks had less self-reported working ability when compared to those without Tumarkin attacks. The current study results suggest various differences in terms of complaints reported, severity of consequences, and the self-reported working ability in MD patients with and without Tumarkin attacks. Hearing healthcare professionals must examine Tumarkin attacks and their consequences in patients with MD during clinical examinations. In addition, the therapy should focus on alleviating the consequences and improving work ability.

Netwar

NASA Astrophysics Data System (ADS)

Keen, Arthur A.

2006-04-01

This paper describes technology being developed at 21st Century Technologies to automate Computer Network Operations (CNO). CNO refers to DoD activities related to Attacking and Defending Computer Networks (CNA & CND). Next generation cyber threats are emerging in the form of powerful Internet services and tools that automate intelligence gathering, planning, testing, and surveillance. We will focus on "Search-Engine Hacks", queries that can retrieve lists of router/switch/server passwords, control panels, accessible cameras, software keys, VPN connection files, and vulnerable web applications. Examples include "Titan Rain" attacks against DoD facilities and the Santy worm, which identifies vulnerable sites by searching Google for URLs containing application-specific strings. This trend will result in increasingly sophisticated and automated intelligence-driven cyber attacks coordinated across multiple domains that are difficult to defeat or even understand with current technology. One traditional method of CNO relies on surveillance detection as an attack predictor. Unfortunately, surveillance detection is difficult because attackers can perform search engine-driven surveillance such as with Google Hacks, and avoid touching the target site. Therefore, attack observables represent only about 5% of the attacker's total attack time, and are inadequate to provide warning. In order to predict attacks and defend against them, CNO must also employ more sophisticated techniques and work to understand the attacker's Motives, Means and Opportunities (MMO). CNO must use automated reconnaissance tools, such as Google, to identify information vulnerabilities, and then utilize Internet tools to observe the intelligence gathering, planning, testing, and collaboration activities that represent 95% of the attacker's effort.

Securing internet by eliminating DDOS attacks

NASA Astrophysics Data System (ADS)

Niranchana, R.; Gayathri Devi, N.; Santhi, H.; Gayathri, P.

2017-11-01

The major threat caused to the authorised usage of Internet is Distributed Denial of Service attack. The mechanisms used to prevent the DDoS attacks are said to overcome the attack’s ability in spoofing the IP packets source addresses. By utilising Internet Protocol spoofing, the attackers cause a consequential load over the networks destination for policing attack packets. To overcome the IP Spoofing level on the Internet, We propose an Inter domain Packet Filter (IPF) architecture. The proposed scheme is not based on global routing information. The packets with reliable source addresses are not rejected, the IPF frame work works in such a manner. The spoofing capability of attackers is confined by IPF, and also the filter identifies the source of an attack packet by minimal number of candidate network.

Monitoring the Attack Incidences and Damage Caused by the Almond Bark Beetle, Scolytus amygdali, in Almond Orchards

PubMed Central

Cuthbertson, Andrew G. S.; Braham, Mohamed

2018-01-01

The almond bark beetle, Scolytus amygdali Geurin-Meneville, is responsible for significant loss of fruit production in almond orchards throughout the world. Here, we studied the damage and the incidences of S. amygdali attack on two different scales: (1) at the level of a single tree; and (2) in an entire orchard. Our results revealed no differences in attack level among four orientations (east, west, south and north sides) for the whole tree. However, the bark that was facing west side in the direction of the prevailing wind was found to be the most suitable for females to initiate attack in Stratum S2. Attack distribution remains the same among different strata (strata is vertical divisions of the tree from the ground to the uppermost twigs with ~40 cm intervals). More than 50% of attack was observed in the trunk of the tree and upper strata. However, multiplication rate (number of emerged adults/maternal gallery) varies significantly between strata. In addition, we studied attack intensity (holes produced by beetle per tree) comparing it to tree morphology (flowers, leaves and circumferences) and gum deposit. Our results revealed a positive correlation between attack intensity and gum deposits, and a negative correlation between attack intensity and tree morphology. This revealed that gum on the tree was an indicator for attack intensity. A positive correlation between attack intensity and the circumference of the tree revealed that older trees were more susceptible to S. amygdali attack. These results, while preliminary, aim to help in the monitoring of S. amygdali populations before deciding to apply any control measures. PMID:29301271

On the IDAGAM I Combat Model.

DTIC Science & Technology

1977-06-01

defense missions in locations between the FEBA and the attackers’ targets; b) AAA can attack only aircraft attacking the guns them- selves or the targets...the guns are defending; c) SAM weapon systems can attack not only aircraft attack- ing them and the targets they defend but also, although possibly...Corporation), P.E. Louer (Department of the Army) and B.R. McEnany (Joint Chiefs of Staff/Studies, Analysis and Gaming Agency) for their help- ful

Terror attacks influence driving behavior in Israel

PubMed Central

Stecklov, Guy; Goldstein, Joshua R.

2004-01-01

Terror attacks in Israel produce a temporary lull in light accidents followed by a 35% spike in fatal accidents on Israeli roads 3 days after the attack. Our results are based on time-series analysis of Israeli traffic flows, accidents, and terror attacks from January 2001 through June 2002. Whereas prior studies have focused on subjective reports of posttraumatic stress, our study shows a population-level behavioral response to violent terror attacks. PMID:15448203

Childhood Internalizing and Externalizing Problems Predict the Onset of Clinical Panic Attacks over Adolescence: The TRAILS Study

PubMed Central

Mathyssek, Christina M.; Olino, Thomas M.; Verhulst, Frank C.; van Oort, Floor V. A.

2012-01-01

Background Panic attacks are a source of individual suffering and are an independent risk factor for later psychopathology. However, much less is known about risk factors for the development of panic attacks, particularly during adolescence when the incidence of panic attacks increases dramatically. We examined whether internalizing and externalizing problems in childhood predict the onset of panic attacks in adolescence. Method This study is part of the TRacking Adolescents’ Individual Lives Survey (TRAILS), a Dutch longitudinal population cohort study (N = 1,584). Internalizing and Externalizing Problems were collected using the Youth Self-Report (YSR) and the parent-report Child Behavior Checklist (CBCL) at baseline (age 10–12). At age 18–20, DSM-IV defined panic attacks since baseline were assessed with the Composite International Diagnostic Interview (CIDI). We investigated whether early adolescent Internalizing and Externalizing Problems predicted panic attacks between ages 10–20 years, using survival analysis in univariate and multivariate models. Results There were N = 314 (19.8%) cases who experienced at least one DSM-IV defined panic attack during adolescence and N = 18 (1.2%) who developed panic disorder during adolescence. In univariate analyses, CBCL Total Problems, Internalizing Problems and three of the eight syndrome scales predicted panic attack onset, while on the YSR all broad-band problem scales and each narrow-band syndrome scale predicted panic attack onset. In multivariate analyses, CBCL Social Problems (HR 1.19, p<.05), and YSR Thought Problems (HR 1.15, p<.05) and Social Problems (HR 1.26, p<.01) predicted panic attack onset. Conclusion Risk indicators of panic attack include the wide range of internalizing and externalizing problems. Yet, when adjusted for co-occurring problem behaviors, Social Problems were the most consistent risk factor for panic attack onsets in adolescence. PMID:23251576

Effectiveness of icatibant for treatment of hereditary angioedema attacks is not affected by body weight: findings from the Icatibant Outcome Survey, a cohort observational study.

PubMed

Caballero, Teresa; Zanichelli, Andrea; Aberer, Werner; Maurer, Marcus; Longhurst, Hilary J; Bouillet, Laurence; Andresen, Irmgard

2018-01-01

Icatibant is a bradykinin B2-receptor antagonist used for the treatment of hereditary angioedema attacks resulting from C1-inhibitor deficiency. Treatment is not adjusted by body weight however the impact of body mass index (BMI) on the effectiveness of icatibant is not documented in the literature. We examined disease characteristics and icatibant treatment effectiveness in patients stratified by BMI in the Icatibant Outcome Survey, an ongoing, international, observational study monitoring the real-world safety and effectiveness of icatibant. Attack and treatment characteristics as well as outcomes following treatment with icatibant were compared among patients with underweight, normal, overweight, and obese BMI. Data from 2697 icatibant-treated attacks in 342 patients (3.5, 44.7, 34.8, and 17.0% patients of underweight, normal, overweight, and obese BMI, respectively) were analyzed. There was no significant difference in the frequency and severity of attacks across BMI groups, although obese patients tended to have more attacks of high severity. There was no impact of BMI on the frequency of laryngeal attacks, but patients with normal BMI had fewer cutaneous attacks and more abdominal attacks. Most attacks (71.9-83.8%) were treated with a single icatibant injection without the need for rescue with plasma-derived C1-inhibitor (pdC1-INH), regardless of BMI. Patients with obese BMI used pdC1-INH as rescue treatment more often (P < 0.0001; P = 0.0232 excluding 2 outliers) and treated attacks earlier than patients with normal BMI (P = 0.007). Furthermore, time to resolution and duration of attack were shorter for patients with high BMI (P < 0.001 for overweight and P < 0.05 for obese versus normal). Overall, icatibant was comparatively effective in treating attacks in patients across all BMI groups. Trial registration NCT01034969.

Somatic panic-attack equivalents in a community sample of Rwandan widows who survived the 1994 genocide

PubMed Central

Hagengimana, Athanase; Hinton, Devon; Bird, Bruce; Pollack, Mark; Pitman, Roger K.

2009-01-01

The present study is the first to attempt to determine rates of panic attacks, especially ‘somatically focused’ panic attacks, panic disorder, symptoms of post-traumatic stress disorder (PTSD), and depression levels in a population of Rwandans traumatized by the 1994 genocide. The following measures were utilized: the Rwandan Panic-Disorder Survey (RPDS); the Beck Depression Inventory (BDI); the Harvard Trauma Questionnaire (HTQ); and the PTSD Checklist (PCL). Forty of 100 Rwandan widows suffered somatically focused panic attacks during the previous 4 weeks. Thirty-five (87%) of those having panic attacks suffered panic disorder, making the rate of panic disorder for the entire sample 35%. Rwandan widows with panic attacks had greater psychopathology on all measures. Somatically focused panic-attack subtypes seem to constitute a key response to trauma in the Rwandan population. Future studies of traumatized non-Western populations should carefully assess not only somatoform disorder but also somatically focused panic attacks. PMID:12581815

Sub-threshold panic attacks and agoraphobic avoidance increase comorbidity of mental disorders: results from an adult general population sample.

PubMed

Pané-Farré, Christiane A; Fenske, Kristin; Stender, Jan P; Meyer, Christian; John, Ulrich; Rumpf, Hans-Jürgen; Hapke, Ulfert; Hamm, Alfons O

2013-06-01

Full-blown panic attacks are frequently associated with other mental disorders. Most comorbidity analyses did not discriminate between isolated panic attacks vs. panic attacks that occurred in the context of a panic disorder and rarely evaluated the impact of comorbid agoraphobia. Moreover, there are no larger scale epidemiological studies regarding the influence of sub-threshold panic attacks. 4075 German-speaking respondents aged 18-64 were interviewed using the fully structured Munich Composite International Diagnostic Interview. Limited symptom attacks, isolated panic attacks, and panic disorder were associated with other lifetime DSM-IV disorders with monotonically increasing odds and increasing tendency for multiple comorbidities across the three groups. The presence of agoraphobia was associated with more frequent comorbidity in all panic subgroups and also in persons who never experienced panic attacks. The present study suggests that populations with isolated or limited symptom should be carefully attended to in clinical practice, especially if agoraphobia is present. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Game Theoretical Approach to Hacktivism: Is Attack Likelihood a Product of Risks and Payoffs?

PubMed

Bodford, Jessica E; Kwan, Virginia S Y

2018-02-01

The current study examines hacktivism (i.e., hacking to convey a moral, ethical, or social justice message) through a general game theoretic framework-that is, as a product of costs and benefits. Given the inherent risk of carrying out a hacktivist attack (e.g., legal action, imprisonment), it would be rational for the user to weigh these risks against perceived benefits of carrying out the attack. As such, we examined computer science students' estimations of risks, payoffs, and attack likelihood through a game theoretic design. Furthermore, this study aims at constructing a descriptive profile of potential hacktivists, exploring two predicted covariates of attack decision making, namely, peer prevalence of hacking and sex differences. Contrary to expectations, results suggest that participants' estimations of attack likelihood stemmed solely from expected payoffs, rather than subjective risks. Peer prevalence significantly predicted increased payoffs and attack likelihood, suggesting an underlying descriptive norm in social networks. Notably, we observed no sex differences in the decision to attack, nor in the factors predicting attack likelihood. Implications for policymakers and the understanding and prevention of hacktivism are discussed, as are the possible ramifications of widely communicated payoffs over potential risks in hacking communities.

Sequential defense against random and intentional attacks in complex networks.

PubMed

Chen, Pin-Yu; Cheng, Shin-Ming

2015-02-01

Network robustness against attacks is one of the most fundamental researches in network science as it is closely associated with the reliability and functionality of various networking paradigms. However, despite the study on intrinsic topological vulnerabilities to node removals, little is known on the network robustness when network defense mechanisms are implemented, especially for networked engineering systems equipped with detection capabilities. In this paper, a sequential defense mechanism is first proposed in complex networks for attack inference and vulnerability assessment, where the data fusion center sequentially infers the presence of an attack based on the binary attack status reported from the nodes in the network. The network robustness is evaluated in terms of the ability to identify the attack prior to network disruption under two major attack schemes, i.e., random and intentional attacks. We provide a parametric plug-in model for performance evaluation on the proposed mechanism and validate its effectiveness and reliability via canonical complex network models and real-world large-scale network topology. The results show that the sequential defense mechanism greatly improves the network robustness and mitigates the possibility of network disruption by acquiring limited attack status information from a small subset of nodes in the network.

Induction of panic attack by stimulation of the ventromedial hypothalamus.

PubMed

Wilent, W Bryan; Oh, Michael Y; Buetefisch, Cathrin M; Bailes, Julian E; Cantella, Diane; Angle, Cindy; Whiting, Donald M

2010-06-01

Panic attacks are sudden debilitating attacks of intense distress often accompanied by physical symptoms such as shortness of breath and heart palpitations. Numerous brain regions, hormones, and neurotransmitter systems are putatively involved, but the etiology and neurocircuitry of panic attacks is far from established. One particular brain region of interest is the ventromedial hypothalamus (VMH). In cats and rats, electrical stimulation delivered to the VMH has been shown to evoke an emotional "panic attack-like" escape behavior, and in humans, stimulation targeting nuclei just posterior or anterior to the VMH has reportedly induced panic attacks. The authors report findings obtained in an awake patient undergoing bilateral implantation of deep brain stimulation electrodes into the hypothalamus that strongly implicates the VMH as being critically involved in the genesis of panic attacks. First, as the stimulating electrode progressed deeper into the VMH, the intensity of stimulation required to evoke an attack systematically decreased; second, while stimulation of the VMH in either hemisphere evoked panic, stimulation that appeared to be in the center of the VMH was more potent. Thus, this evidence supports the role of the VMH in the induction of panic attacks purported by animal studies.

Random Visitor: Defense against Identity Attacks in P2P Networks

NASA Astrophysics Data System (ADS)

Gu, Jabeom; Nah, Jaehoon; Kwon, Hyeokchan; Jang, Jonsoo; Park, Sehyun

Various advantages of cooperative peer-to-peer networks are strongly counterbalanced by the open nature of a distributed, serverless network. In such networks, it is relatively easy for an attacker to launch various attacks such as misrouting, corrupting, or dropping messages as a result of a successful identifier forgery. The impact of an identifier forgery is particularly severe because the whole network can be compromised by attacks such as Sybil or Eclipse. In this paper, we present an identifier authentication mechanism called random visitor, which uses one or more randomly selected peers as delegates of identity proof. Our scheme uses identity-based cryptography and identity ownership proof mechanisms collectively to create multiple, cryptographically protected indirect bindings between two peers, instantly when needed, through the delegates. Because of these bindings, an attacker cannot achieve an identifier forgery related attack against interacting peers without breaking the bindings. Therefore, our mechanism limits the possibility of identifier forgery attacks efficiently by disabling an attacker's ability to break the binding. The design rationale and framework details are presented. A security analysis shows that our scheme is strong enough against identifier related attacks and that the strength increases if there are many peers (more than several thousand) in the network.

Detecting and Preventing Sybil Attacks in Wireless Sensor Networks Using Message Authentication and Passing Method.

PubMed

Dhamodharan, Udaya Suriya Raj Kumar; Vayanaperumal, Rajamani

2015-01-01

Wireless sensor networks are highly indispensable for securing network protection. Highly critical attacks of various kinds have been documented in wireless sensor network till now by many researchers. The Sybil attack is a massive destructive attack against the sensor network where numerous genuine identities with forged identities are used for getting an illegal entry into a network. Discerning the Sybil attack, sinkhole, and wormhole attack while multicasting is a tremendous job in wireless sensor network. Basically a Sybil attack means a node which pretends its identity to other nodes. Communication to an illegal node results in data loss and becomes dangerous in the network. The existing method Random Password Comparison has only a scheme which just verifies the node identities by analyzing the neighbors. A survey was done on a Sybil attack with the objective of resolving this problem. The survey has proposed a combined CAM-PVM (compare and match-position verification method) with MAP (message authentication and passing) for detecting, eliminating, and eventually preventing the entry of Sybil nodes in the network. We propose a scheme of assuring security for wireless sensor network, to deal with attacks of these kinds in unicasting and multicasting.

Detecting and Preventing Sybil Attacks in Wireless Sensor Networks Using Message Authentication and Passing Method

PubMed Central

Dhamodharan, Udaya Suriya Raj Kumar; Vayanaperumal, Rajamani

2015-01-01

Wireless sensor networks are highly indispensable for securing network protection. Highly critical attacks of various kinds have been documented in wireless sensor network till now by many researchers. The Sybil attack is a massive destructive attack against the sensor network where numerous genuine identities with forged identities are used for getting an illegal entry into a network. Discerning the Sybil attack, sinkhole, and wormhole attack while multicasting is a tremendous job in wireless sensor network. Basically a Sybil attack means a node which pretends its identity to other nodes. Communication to an illegal node results in data loss and becomes dangerous in the network. The existing method Random Password Comparison has only a scheme which just verifies the node identities by analyzing the neighbors. A survey was done on a Sybil attack with the objective of resolving this problem. The survey has proposed a combined CAM-PVM (compare and match-position verification method) with MAP (message authentication and passing) for detecting, eliminating, and eventually preventing the entry of Sybil nodes in the network. We propose a scheme of assuring security for wireless sensor network, to deal with attacks of these kinds in unicasting and multicasting. PMID:26236773

Attack Detection in Sensor Network Target Localization Systems With Quantized Data

NASA Astrophysics Data System (ADS)

Zhang, Jiangfan; Wang, Xiaodong; Blum, Rick S.; Kaplan, Lance M.

2018-04-01

We consider a sensor network focused on target localization, where sensors measure the signal strength emitted from the target. Each measurement is quantized to one bit and sent to the fusion center. A general attack is considered at some sensors that attempts to cause the fusion center to produce an inaccurate estimation of the target location with a large mean-square-error. The attack is a combination of man-in-the-middle, hacking, and spoofing attacks that can effectively change both signals going into and coming out of the sensor nodes in a realistic manner. We show that the essential effect of attacks is to alter the estimated distance between the target and each attacked sensor to a different extent, giving rise to a geometric inconsistency among the attacked and unattacked sensors. Hence, with the help of two secure sensors, a class of detectors are proposed to detect the attacked sensors by scrutinizing the existence of the geometric inconsistency. We show that the false alarm and miss probabilities of the proposed detectors decrease exponentially as the number of measurement samples increases, which implies that for sufficiently large number of samples, the proposed detectors can identify the attacked and unattacked sensors with any required accuracy.

39 CFR 501.11 - Reporting Postage Evidencing System security weaknesses.

Code of Federal Regulations, 2014 CFR

2014-07-01

... any repeatable deviation from normal Postage Evidencing System performance. (3) Cyber attacks that... misappropriating assets or sensitive information, corrupting data, or causing operational disruption. Cyber attacks... causing denial-of-service attacks on Web sites. Cyber attacks may be carried out by third parties or...

39 CFR 501.11 - Reporting Postage Evidencing System security weaknesses.

Code of Federal Regulations, 2013 CFR

2013-07-01

... any repeatable deviation from normal Postage Evidencing System performance. (3) Cyber attacks that... misappropriating assets or sensitive information, corrupting data, or causing operational disruption. Cyber attacks... causing denial-of-service attacks on Web sites. Cyber attacks may be carried out by third parties or...

39 CFR 501.11 - Reporting Postage Evidencing System security weaknesses.

Code of Federal Regulations, 2012 CFR

2012-07-01

... any repeatable deviation from normal Postage Evidencing System performance. (3) Cyber attacks that... misappropriating assets or sensitive information, corrupting data, or causing operational disruption. Cyber attacks... causing denial-of-service attacks on Web sites. Cyber attacks may be carried out by third parties or...

Sustaining U.S. Nuclear Submarine Design Capabilities

DTIC Science & Technology

2007-01-01

lost learning because there is an inherent novelty to each succeeding design effort, but on the other hand, higher 2 Note there is a unique “do...Nautilus 1 1954 Attack Seawolf 1 1957 Attack Skate 4 1958–1959 Attack Skipjack 6 1959–1961 Attack Triton 1 1959 Attack George Washington 5 1960–1962...development, electric motors and controls development, or equipment acoustic analysis (listed to the right of the pyramid). All of these skills have some

National Counterterrorism Center: 2007 Report on Terrorism

DTIC Science & Technology

2008-04-30

Approximately one half of the attacks in the NCTC database involve no loss of life. An attack that damages a pipeline and a car bomb attack that kills 100...rose by about 30 percent and 20 percent, respectively. Overall, suicide bombing attacks rose by about 50 percent and suicide car bombings about 40...January 2007, in Nukhaib, Al Anbar, Iraq, armed assailants in three cars attacked two buses transporting Shiite pilgrims back from the Hajj in Mecca to Al

Combating Paramilitary Terrorism on the Homefront: An Examination of Capabilities and Limitations of U.S. Response Forces

DTIC Science & Technology

2015-12-01

paramilitary methods with devastating results. This thesis examines the paramilitary terrorist attacks that occurred in Beslan in 2004 and in Mumbai in...paramilitary attack to be established. 14. SUBJECT TERMS paramilitary terrorism, North Hollywood shootout, Mumbai attack, Beslan school attack, posse...paramilitary terrorist attacks that occurred in Beslan in 2004 and in Mumbai in 2008 in an attempt to understand the threat and to establish the criteria for

US Army Attack Aviation in a Decisive Action Environment: History, Doctrine, and a Need for Doctrinal Refinement

DTIC Science & Technology

2015-05-23

flight. The design used the engine, transmission, and rotor system of the UH-1 design. In doing so, Bell helicopters publicly declared that the Cobra...Public Release; Distribution is Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The attack helicopter airframe and role evolved slowly, over time, to...attack helicopter doctrine, heavily influenced by the Global War on Terror and the 11th Attack Helicopter Regiment’s disastrous deep attack during

Attack rates of Sirex noctilio and patterns of pine tree defenses and mortality in northern Patagonia.

PubMed

Martinson, S J; Fernádez Ajó, A A; Martínez, A S; Krivak-Tetley, F E; Villacide, J M; Ayres, M P; Corley, J C

2018-04-18

Accidental and intentional global movement of species has increased the frequency of novel plant-insect interactions. In Patagonia, the European woodwasp, Sirex noctilio, has invaded commercial plantations of North American pines. We compared the patterns of resin defenses and S. noctilio-caused mortality at two mixed-species forests near San Carlos de Bariloche, Argentina. We observed lower levels of resin flow and higher levels of mortality in Pinus contorta compared with Pinus ponderosa. In general, S. noctilio attacked trees with lower resin compared with neighboring trees. Resin production in P. ponderosa was not related to growth rates, but for P. contorta, slower growing trees produced less resin than faster growing conspecifics. For all infested trees, attack density and number of drills (ovipositor probes) per attack did not vary with resin production. Most attacks resulted in one or two drills. Attack rates and drills/attack were basically uniform across the bole of the tree except for a decrease in both drills/attack and attack density in the upper portion of the crown, and an increase in the attack density for the bottom 10% of the tree. Planted pines in Patagonia grow faster than their counterparts in North America, and produce less resin, consistent with the growth-differentiation balance hypothesis. Limited resin defenses may help to explain the high susceptibility of P. contorta to woodwasps in Patagonia.

Management of children and young people (CYP) with asthma: a clinical audit report.

PubMed

Levy, Mark L; Ward, Angela; Nelson, Sara

2018-05-21

An asthma attack or exacerbation signals treatment failure. Most attacks are preventable and failure to recognize risk of asthma attacks are well recognized as risk factors for future attacks and even death. Of the 19 recommendations made by the United Kingdom National Review of Asthma Deaths (NRAD) (1) only one has been partially implemented-a National Asthma Audit; however, this hasn't reported yet. The Harrow Clinical Commissioning Group (CCG) in London implemented a clinical asthma audit on 291 children and young people aged under 19 years (CYP) who had been treated for asthma attacks in 2016. This was funded as a Local Incentive Scheme (LIS) aimed at improving quality health care delivery. Two years after the publication of the NRAD report it is surprising that risks for future attacks were not recognized, that few patients were assessed objectively during attacks and only 10% of attacks were followed up within 2 days. However, it is encouraging that CYP hospital admissions following the audit were reduced by 16%, with clear benefit for patients, their families and the local health economy. This audit has provided an example of how clinicians can focus learning on patients who have had asthma attacks and utilize these events as a catalyst for active reflection in particular on modifiable risk factors. Through identification of these risks and active optimization of management, preventable asthma attacks could become 'never events'.

Alligator attacks in southwest Florida.

PubMed

Harding, Brett E; Wolf, Barbara C

2006-05-01

The American alligator inhabits bodies of fresh water in Florida and other southeastern states. Although attacks on pets are frequent, alligator attacks on humans are relatively rare because of the animal's natural fear of man. Because of the rarity of attacks on humans, the pathologic findings and pathophysiology of death in such cases have not been well characterized in the literature. We report three cases of fatal alligator attacks that occurred in southwest Florida, each with different pathologic findings and mechanisms of death. Although the cause of death in each case was attributed to the alligator attack, the mechanisms of death differed and included exsanguination because of amputation of an extremity, overwhelming sepsis, and drowning. These cases illustrate the varied pathophysiologies associated with deaths due to alligator attacks on humans and the features that distinguish alligator bites from those of other aquatic predators.

A closer look at the relationships between panic attacks, emergency department visits and non-cardiac chest pain.

PubMed

Foldes-Busque, Guillaume; Denis, Isabelle; Poitras, Julien; Fleet, Richard P; Archambault, Patrick; Dionne, Clermont E

2017-01-01

This study examined the prevalence of emergency department visits prompted by panic attacks in patients with non-cardiac chest pain. A validated structured telephone interview was used to assess panic attacks and their association with the emergency department consultation in 1327 emergency department patients with non-cardiac chest pain. Patients reported at least one panic attack in the past 6 months in 34.5 per cent (95% confidence interval: 32.0%-37.1%) of cases, and 77.1 per cent (95% confidence interval: 73.0%-80.7%) of patients who reported panic attacks had visited the emergency department with non-cardiac chest pain following a panic attack. These results indicate that panic attacks may explain a significant proportion of emergency department visits for non-cardiac chest pain.

Develop a solution for protecting and securing enterprise networks from malicious attacks

NASA Astrophysics Data System (ADS)

Kamuru, Harshitha; Nijim, Mais

2014-05-01

In the world of computer and network security, there are myriad ways to launch an attack, which, from the perspective of a network, can usually be defined as "traffic that has huge malicious intent." Firewall acts as one of the measure in order to secure the device from incoming unauthorized data. There are infinite number of computer attacks that no firewall can prevent, such as those executed locally on the machine by a malicious user. From the network's perspective, there are numerous types of attack. All the attacks that degrade the effectiveness of data can be grouped into two types: brute force and precision. The Firewall that belongs to Juniper has the capability to protect against both types of attack. Denial of Service (DoS) attacks are one of the most well-known network security threats under brute force attacks, which is largely due to the high-profile way in which they can affect networks. Over the years, some of the largest, most respected Internet sites have been effectively taken offline by Denial of Service (DOS) attacks. A DoS attack typically has a singular focus, namely, to cause the services running on a particular host or network to become unavailable. Some DoS attacks exploit vulnerabilities in an operating system and cause it to crash, such as the infamous Win nuke attack. Others submerge a network or device with traffic so that there are no more resources to handle legitimate traffic. Precision attacks typically involve multiple phases and often involves a bit more thought than brute force attacks, all the way from reconnaissance to machine ownership. Before a precision attack is launched, information about the victim needs to be gathered. This information gathering typically takes the form of various types of scans to determine available hosts, networks, and ports. The hosts available on a network can be determined by ping sweeps. The available ports on a machine can be located by port scans. Screens cover a wide variety of attack traffic as they are configured on a per-zone basis. Depending on the type of screen being configured, there may be additional settings beyond simply blocking the traffic. Attack prevention is also a native function of any firewall. Juniper Firewall handles traffic on a per-flow basis. We can use flows or sessions as a way to determine whether traffic attempting to traverse the firewall is legitimate. We control the state-checking components resident in Juniper Firewall by configuring "flow" settings. These settings allow you to configure state checking for various conditions on the device. You can use flow settings to protect against TCP hijacking, and to generally ensure that the fire-wall is performing full state processing when desired. We take a case study of attack on a network and perform study of the detection of the malicious packets on a Net screen Firewall. A new solution for securing enterprise networks will be developed here.

Percolation Features on Climate Network under Attacks of El Niño Events

NASA Astrophysics Data System (ADS)

Lu, Z.

2015-12-01

Percolation theory under different attacks is one of the main research areas in complex networks but never be applied to investigate climate network. In this study, for the first time we construct a climate network of surface air temperature field to analyze its percolation features. Here, we regard El Niño event as a kind of naturally attacks generated from Pacific Ocean to attack its upper climate network. We find that El Niño event leads an abrupt percolation phase transition to the climate network which makes it splitting and unstable suddenly. Comparing the results of the climate network under three different forms of attacks, including most connected attack (MA), localized attack (LA) and random attack (RA) respectively, it is found that both MA and LA lead first-order transition and RA leads second-order transition to the climate network. Furthermore, we find that most real attacks consist of all these three forms of attacks. With El Niño event emerging, the ratios of LA and MA increase and dominate the style of attack while RA decreasing. It means the percolation phase transition due to El Niño events is close to first-order transition mostly affected by LA and MA. Our research may help us further understand two questions from perspective of percolation on network: (1) Why not all warming in Pacific Ocean but El Niño events could affect the climate. (2) Why the climate affected by El Niño events changes abruptly.

Symptom Induction and De-escalation in the Treatment of Panic Attacks.

ERIC Educational Resources Information Center

Dattilio, Frank M.

1990-01-01

Describes technique known as symptom induction and de-escalation for panic attacks in which goal is to reproduce the type of situation that may precipitate an attack and then to show the client how the attacks can be "turned on" as well as "turned off." (ABL)

Don't Take a Chance with a Heart Attack: Know the Facts and Act Fast

MedlinePlus

heart attack Know the symptoms. Take action. call Don’t Take a Chance With a Heart Attack: Know the Facts and Act Fast “ One evening ... didn’t think I could be having a heart attack. I didn’t expect it to happen to ...

Learn What a Heart Attack Feels Like--It Could Save Your Life

MedlinePlus

Learn What a Heart Attack Feels Like— It Could Save Your Life. This fact sheet tells you about heart attack signs. It also tells you what to ... heart attack warning signs. Your chest hurts or feels squeezed. One or both arms, your back, shoulders, ...

Case report: Pig attack with successful postexposure prophylaxis management.

PubMed

Hall, A Brad; Smith, David; Palmer, Jillian

2014-05-01

The domesticated pig or boar is ubiquitous to agriculture around the world and is an important food product in most countries. The males that are able to grow tusks that can approach 5 in are the primary contributor to morbidity and mortality from boar attacks. Literature surrounding domesticated boar attacks is sparse. There are no published cases of domesticated boar attacks that describe successful bacterial postexposure prophylaxis. We present a case report of an attack on an adult female by a domesticated boar.

Cougar attacks on humans: a case report.

PubMed

McKee, Denise

2003-01-01

Cougar attacks on humans are increasing. Presented is a case report of a nonfatal 2-year-old male cougar attack on an 8-year-old girl in British Columbia. Discussions of wound management, rabies postexposure prophylaxis (RPEP), and the possible psychologic ramifications of such an attack are presented. Also reviewed are recommendations on actions that may be helpful in preventing an attack following a sudden encounter with a cougar. Humans must learn to coexist with cougars, which present a small but real threat to people.

Epidemics of panic during a bioterrorist attack--a mathematical model.

PubMed

Radosavljevic, Vladan; Radunovic, Desanka; Belojevic, Goran

2009-09-01

A bioterrorist attacks usually cause epidemics of panic in a targeted population. We have presented epidemiologic aspect of this phenomenon as a three-component model--host, information on an attack and social network. We have proposed a mathematical model of panic and counter-measures as the function of time in a population exposed to a bioterrorist attack. The model comprises ordinary differential equations and graphically presented combinations of the equations parameters. Clinically, we have presented a model through a sequence of psychic conditions and disorders initiated by an act of bioterrorism. This model might be helpful for an attacked community to timely and properly apply counter-measures and to minimize human mental suffering during a bioterrorist attack.

Framework and methodology for supply chain lifecycle analytics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamlet, Jason; Eames, Brandon K.; Kao, Gio K.

The various technologies presented herein relate to pertaining to identifying and mitigating risks and attacks on a supply chain. A computer-implemented representation of a supply chain is generated comprising nodes (locations) and edges (objects, information). Risk to attack and different attack vectors can be defined for the various nodes and edges, and further, based upon the risks and attacks, (difficulty, consequence) pairs can be determined. One or more mitigations can be generated to increase a difficulty of attack and/or reduce consequence of an attack. The one or more mitigations can be constrained, e.g., by cost, time, etc., to facilitate determinationmore » of how feasible a respective mitigation is to implement with regard to finances available, duration to implement, etc. A context-free grammar can be utilized to identify one or more attacks in the supply chain. Further, the risks can undergo a ranking to enable mitigation priority to be determined.« less

Wind-tunnel investigation of the flow correction for a model-mounted angle of attack sensor at angles of attack from -10 deg to 110 deg. [Langley 12-foot low speed wind tunnel test

NASA Technical Reports Server (NTRS)

Moul, T. M.

1979-01-01

A preliminary wind tunnel investigation was undertaken to determine the flow correction for a vane angle of attack sensor over an angle of attack range from -10 deg to 110 deg. The sensor was mounted ahead of the wing on a 1/5 scale model of a general aviation airplane. It was shown that the flow correction was substantial, reaching about 15 deg at an angle of attack of 90 deg. The flow correction was found to increase as the sensor was moved closer to the wing or closer to the fuselage. The experimentally determined slope of the flow correction versus the measured angle of attack below the stall angle of attack agreed closely with the slope of flight data from a similar full scale airplane.

Modeling and Managing Risk in Billing Infrastructures

NASA Astrophysics Data System (ADS)

Baiardi, Fabrizio; Telmon, Claudio; Sgandurra, Daniele

This paper discusses risk modeling and risk management in information and communications technology (ICT) systems for which the attack impact distribution is heavy tailed (e.g., power law distribution) and the average risk is unbounded. Systems with these properties include billing infrastructures used to charge customers for services they access. Attacks against billing infrastructures can be classified as peripheral attacks and backbone attacks. The goal of a peripheral attack is to tamper with user bills; a backbone attack seeks to seize control of the billing infrastructure. The probability distribution of the overall impact of an attack on a billing infrastructure also has a heavy-tailed curve. This implies that the probability of a massive impact cannot be ignored and that the average impact may be unbounded - thus, even the most expensive countermeasures would be cost effective. Consequently, the only strategy for managing risk is to increase the resilience of the infrastructure by employing redundant components.

Attack-tolerant networked control system: an approach for detection the controller stealthy hijacking attack

NASA Astrophysics Data System (ADS)

Atta Yaseen, Amer; Bayart, Mireille

2017-01-01

In this work, a new approach will be introduced as a development for the attack-tolerant scheme in the Networked Control System (NCS). The objective is to be able to detect an attack such as the Stuxnet case where the controller is reprogrammed and hijacked. Besides the ability to detect the stealthy controller hijacking attack, the advantage of this approach is that there is no need for a priori mathematical model of the controller. In order to implement the proposed scheme, a specific detector for the controller hijacking attack is designed. The performance of this scheme is evaluated be connected the detector to NCS with basic security elements such as Data Encryption Standard (DES), Message Digest (MD5), and timestamp. The detector is tested along with networked PI controller under stealthy hijacking attack. The test results of the proposed method show that the hijacked controller can be significantly detected and recovered.

Mental health service use among American Red Cross disaster workers responding to the September 11, 2001 U.S. terrorist attacks.

PubMed

Elhai, Jon D; Jacobs, Gerard A; Kashdan, Todd B; DeJong, Gary L; Meyer, David L; Frueh, B Christopher

2006-06-30

In this article, we explored 1) the extent of mental health (MH) service use by American Red Cross disaster relief workers, both before (lifetime) and 1 year after the September 11, 2001 terrorist attacks, and 2) demographic, disaster and MH variables predicting (1-year) post-September 11 MH service use in this population. A sample of 3015 Red Cross disaster workers was surveyed 1 year after the attacks, regarding demographic characteristics, MH service use before and since the attacks, and posttraumatic stress disorder (PTSD) symptoms. Findings revealed that while 13.5% used MH services before the attacks, 10.7% used services after. Variables increasing the likelihood of MH service use after the attacks included the following: no previous MH treatment, younger age, being divorced/widowed, and higher PTSD intrusion or hyperarousal symptoms. Findings support other recent research on MH service use after the September 11 attacks.

Monitoring of continuous-variable quantum key distribution system in real environment.

PubMed

Liu, Weiqi; Peng, Jinye; Huang, Peng; Huang, Duan; Zeng, Guihua

2017-08-07

How to guarantee the practical security of continuous-variable quantum key distribution (CVQKD) system has been an important issue in the quantum cryptography applications. In contrast to the previous practical security strategies, which focus on the intercept-resend attack or the Gaussian attack, we investigate the practical security strategy based on a general attack, i.e., an arbitrated individual attack or collective attack on the system by Eve in this paper. The low bound of intensity disturbance of the local oscillator signal for eavesdropper successfully concealing herself is obtained, considering all noises can be used by Eve in the practical environment. Furthermore, we obtain an optimal monitoring condition for the practical CVQKD system so that legitimate communicators can monitor the general attack in real-time. As examples, practical security of two special systems, i.e., the Gaussian modulated coherent state CVQKD system and the middle-based CVQKD system, are investigated under the intercept-resend attacks.

An analysis of influenza outbreaks in institutions and enclosed societies.

PubMed

Finnie, T J R; Copley, V R; Hall, I M; Leach, S

2014-01-01

This paper considers the reported attack ratio arising from outbreaks of influenza in enclosed societies. These societies are isolated from the wider community and have greater opportunities for contact between members which would aid the spread of disease. While the particular kind of society (prison, care home, school, barracks, etc.) was not a significant factor in an adjusted model of attack ratio, a person's occupation within the society was. In particular, children and military personnel suffer a greater attack ratio than other occupational types (staff, prisoners, etc.). There was no temporal trend in final attack ratio nor, with the exception of 1918, do pandemic years show abnormal attack ratios. We also observed that as community size increases, the attack ratio undergoes steep nonlinear decline. This statistical analysis draws attention to how the organization of such societies, their size and the occupations of individuals within them affect the final attack ratio.

Analysis of Network Vulnerability Under Joint Node and Link Attacks

NASA Astrophysics Data System (ADS)

Li, Yongcheng; Liu, Shumei; Yu, Yao; Cao, Ting

2018-03-01

The security problem of computer network system is becoming more and more serious. The fundamental reason is that there are security vulnerabilities in the network system. Therefore, it’s very important to identify and reduce or eliminate these vulnerabilities before they are attacked. In this paper, we are interested in joint node and link attacks and propose a vulnerability evaluation method based on the overall connectivity of the network to defense this attack. Especially, we analyze the attack cost problem from the attackers’ perspective. The purpose is to find the set of least costs for joint links and nodes, and their deletion will lead to serious network connection damage. The simulation results show that the vulnerable elements obtained from the proposed method are more suitable for the attacking idea of the malicious persons in joint node and link attack. It is easy to find that the proposed method has more realistic protection significance.

On Mitigating Distributed Denial of Service Attacks

ERIC Educational Resources Information Center

Gao, Zhiqiang

2006-01-01

Denial of service (DoS) attacks and distributed denial of service (DDoS) attacks are probably the most ferocious threats in the Internet, resulting in tremendous economic and social implications/impacts on our daily lives that are increasingly depending on the well-being of the Internet. How to mitigate these attacks effectively and efficiently…

Cyberprints: Identifying Cyber Attackers by Feature Analysis

ERIC Educational Resources Information Center

Blakely, Benjamin A.

2012-01-01

The problem of attributing cyber attacks is one of increasing importance. Without a solid method of demonstrating the origin of a cyber attack, any attempts to deter would-be cyber attackers are wasted. Existing methods of attribution make unfounded assumptions about the environment in which they will operate: omniscience (the ability to gather,…

77 FR 61433 - Applications and Amendments to Facility Operating Licenses and Combined Licenses Involving...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-09

... attacks up to and including the design basis cyber attack threat, thereby achieving high assurance that... provide assurance that safety-related SSCs are protected from cyber attacks. Implementation of 10 CFR 73... of ``high assurance of adequate protection against cyber attacks.'' The proposed revision would not...

Do attacks by jaguars Panthera onca and pumas Puma concolor (Carnivora: Felidae) on livestock correlate with species richness and relative abundance of wild prey?

PubMed

Burgas, Albert; Amit, Ronit; Lopez, Bernat C

2014-12-01

Abstract: Attacks by big cats on livestock are one of the major causes of human-felid conflicts and, therefore, an important factor in the conservation of these species. It has been argued that a reduction in natural prey abundance promotes attacks on domestic species, but few studies have tested this statement, and some have delivered contradictory results. We investigated whether the occurrence of attacks to livestock by jaguar and puma relates to the abundance and richness of their natural prey. In the rainy season 2009, we tracked potential prey species counting signs of presence along linear transects in 14 non-attacked cattle farms (control) and in 14 attacked cattle farms in NW Costa Rica. There was a negative relationship between the occurrence of attacks and both species richness (p = 0.0014) and abundance (p = 0.0012) of natural prey. Our results support the establishment of actions to promote support and recovery of natural prey, in order to diminish attacks on livestock, while maintaining jaguar and puma populations.

Optimal Attack Strategies Subject to Detection Constraints Against Cyber-Physical Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Yuan; Kar, Soummya; Moura, Jose M. F.

This paper studies an attacker against a cyberphysical system (CPS) whose goal is to move the state of a CPS to a target state while ensuring that his or her probability of being detected does not exceed a given bound. The attacker’s probability of being detected is related to the nonnegative bias induced by his or her attack on the CPS’s detection statistic. We formulate a linear quadratic cost function that captures the attacker’s control goal and establish constraints on the induced bias that reflect the attacker’s detection-avoidance objectives. When the attacker is constrained to be detected at the false-alarmmore » rate of the detector, we show that the optimal attack strategy reduces to a linear feedback of the attacker’s state estimate. In the case that the attacker’s bias is upper bounded by a positive constant, we provide two algorithms – an optimal algorithm and a sub-optimal, less computationally intensive algorithm – to find suitable attack sequences. Lastly, we illustrate our attack strategies in numerical examples based on a remotely-controlled helicopter under attack.« less

Application of the PageRank Algorithm to Alarm Graphs

NASA Astrophysics Data System (ADS)

Treinen, James J.; Thurimella, Ramakrishna

The task of separating genuine attacks from false alarms in large intrusion detection infrastructures is extremely difficult. The number of alarms received in such environments can easily enter into the millions of alerts per day. The overwhelming noise created by these alarms can cause genuine attacks to go unnoticed. As means of highlighting these attacks, we introduce a host ranking technique utilizing Alarm Graphs. Rather than enumerate all potential attack paths as in Attack Graphs, we build and analyze graphs based on the alarms generated by the intrusion detection sensors installed on a network. Given that the alarms are predominantly false positives, the challenge is to identify, separate, and ideally predict future attacks. In this paper, we propose a novel approach to tackle this problem based on the PageRank algorithm. By elevating the rank of known attackers and victims we are able to observe the effect that these hosts have on the other nodes in the Alarm Graph. Using this information we are able to discover previously overlooked attacks, as well as defend against future intrusions.

Localized attacks on spatially embedded networks with dependencies.

PubMed

Berezin, Yehiel; Bashan, Amir; Danziger, Michael M; Li, Daqing; Havlin, Shlomo

2015-03-11

Many real world complex systems such as critical infrastructure networks are embedded in space and their components may depend on one another to function. They are also susceptible to geographically localized damage caused by malicious attacks or natural disasters. Here, we study a general model of spatially embedded networks with dependencies under localized attacks. We develop a theoretical and numerical approach to describe and predict the effects of localized attacks on spatially embedded systems with dependencies. Surprisingly, we find that a localized attack can cause substantially more damage than an equivalent random attack. Furthermore, we find that for a broad range of parameters, systems which appear stable are in fact metastable. Though robust to random failures-even of finite fraction-if subjected to a localized attack larger than a critical size which is independent of the system size (i.e., a zero fraction), a cascading failure emerges which leads to complete system collapse. Our results demonstrate the potential high risk of localized attacks on spatially embedded network systems with dependencies and may be useful for designing more resilient systems.

Optimal Attack Strategies Subject to Detection Constraints Against Cyber-Physical Systems

DOE PAGES

Chen, Yuan; Kar, Soummya; Moura, Jose M. F.

2017-03-31

This paper studies an attacker against a cyberphysical system (CPS) whose goal is to move the state of a CPS to a target state while ensuring that his or her probability of being detected does not exceed a given bound. The attacker’s probability of being detected is related to the nonnegative bias induced by his or her attack on the CPS’s detection statistic. We formulate a linear quadratic cost function that captures the attacker’s control goal and establish constraints on the induced bias that reflect the attacker’s detection-avoidance objectives. When the attacker is constrained to be detected at the false-alarmmore » rate of the detector, we show that the optimal attack strategy reduces to a linear feedback of the attacker’s state estimate. In the case that the attacker’s bias is upper bounded by a positive constant, we provide two algorithms – an optimal algorithm and a sub-optimal, less computationally intensive algorithm – to find suitable attack sequences. Lastly, we illustrate our attack strategies in numerical examples based on a remotely-controlled helicopter under attack.« less

Migraine attack treatment : a tailor-made suit, not one size fits all.

PubMed

Belvis, Robert; Mas, Natalia; Aceituno, Azahara

2014-04-01

About 15% of people in the world suffer migraine attacks. Migraine can induce a great impact in the quality of life, and the costs of medical care and loss of productivity can be also high. Non-steroidal anti-inflammatory drugs (NSAIDs) are the best treatment in mild-to-moderate migraine attacks and triptans are the first line option in the acute treatment of moderate-to-severe migraine attacks. At present, there are seven marketed triptans: sumatriptan, rizatriptan, zolmitriptan, eletriptan, naratriptan, almotriptan and frovatriptan. Obviously, every drug presents different pharmacokinetic and pharmacodynamics properties and, moreover, some triptans have several formulations. The prescription of one of these seven triptans for a specified patient is based in the drug profile: efficacy, safety, pharmacokinetics and pharmacodynamics. Other data to take account in the final prescription are clinical characteristics of the migraine attack (speed of onset, intensity of pain, lasting of the attack) and patient characteristics as working habits, life style or medical history. It is therefore mandatory to perform an individualization of the treatment of migraine attack. In recent years, several new patents of drugs have been registered in the treatment of migraine attack, although most of these are already known drugs that only provide new routes of administration. We present an update on the treatment of the migraine attack.

Robust ECC-based authenticated key agreement scheme with privacy protection for Telecare medicine information systems.

PubMed

Zhang, Liping; Zhu, Shaohui

2015-05-01

To protect the transmission of the sensitive medical data, a secure and efficient authenticated key agreement scheme should be deployed when the healthcare delivery session is established via Telecare Medicine Information Systems (TMIS) over the unsecure public network. Recently, Islam and Khan proposed an authenticated key agreement scheme using elliptic curve cryptography for TMIS. They claimed that their proposed scheme is provably secure against various attacks in random oracle model and enjoys some good properties such as user anonymity. In this paper, however, we point out that any legal but malicious patient can reveal other user's identity. Consequently, their scheme suffers from server spoofing attack and off-line password guessing attack. Moreover, if the malicious patient performs the same time of the registration as other users, she can further launch the impersonation attack, man-in-the-middle attack, modification attack, replay attack, and strong replay attack successfully. To eliminate these weaknesses, we propose an improved ECC-based authenticated key agreement scheme. Security analysis demonstrates that the proposed scheme can resist various attacks and enables the patient to enjoy the remote healthcare services with privacy protection. Through the performance evaluation, we show that the proposed scheme achieves a desired balance between security and performance in comparisons with other related schemes.

Public Figure Attacks in the United States, 1995-2015.

PubMed

Meloy, J Reid; Amman, Molly

2016-09-01

An archival descriptive study of public figure attackers in the United States between 1995 and 2015 was undertaken. Fifty-six incidents were identified, primarily through exhaustive internet searches, composed of 58 attackers and 58 victims. A code book was developed which focused upon victims, offenders, pre-attack behaviors including direct threats, attack characteristics, post-offense and other outcomes, motivations and psychological abstracts. The average interrater agreement for coding of bivariate variables was 0.835 (intraclass correlation coefficient). The three most likely victim categories were politicians, judges, and athletes. Attackers were males, many with a psychiatric disorder, most were grandiose, and most had both a violent and nonviolent criminal history. The known motivations for the attacks were often angry and personal, the most common being dissatisfaction with a judicial or other governmental process (23%). In only one case was the primary motivation to achieve notoriety. Lethality risk during an attack was 55%. Collateral injury or death occurred in 29% of the incidents. Only 5% communicated a direct threat to the target beforehand. The term "publicly intimate figure" is introduced to describe the sociocultural blurring of public and private lives among the targets, and its possible role in some attackers' perceptions and motivations. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Differential Fault Analysis on CLEFIA with 128, 192, and 256-Bit Keys

NASA Astrophysics Data System (ADS)

Takahashi, Junko; Fukunaga, Toshinori

This paper describes a differential fault analysis (DFA) attack against CLEFIA. The proposed attack can be applied to CLEFIA with all supported keys: 128, 192, and 256-bit keys. DFA is a type of side-channel attack. This attack enables the recovery of secret keys by injecting faults into a secure device during its computation of the cryptographic algorithm and comparing the correct ciphertext with the faulty one. CLEFIA is a 128-bit blockcipher with 128, 192, and 256-bit keys developed by the Sony Corporation in 2007. CLEFIA employs a generalized Feistel structure with four data lines. We developed a new attack method that uses this characteristic structure of the CLEFIA algorithm. On the basis of the proposed attack, only 2 pairs of correct and faulty ciphertexts are needed to retrieve the 128-bit key, and 10.78 pairs on average are needed to retrieve the 192 and 256-bit keys. The proposed attack is more efficient than any previously reported. In order to verify the proposed attack and estimate the calculation time to recover the secret key, we conducted an attack simulation using a PC. The simulation results show that we can obtain each secret key within three minutes on average. This result shows that we can obtain the entire key within a feasible computational time.

Relevance of terrorism for Italian students not directly exposed to it: The affective impact of the 2015 Paris and the 2016 Brussels attacks.

PubMed

Raccanello, Daniela; Burro, Roberto; Brondino, Margherita; Pasini, Margherita

2018-04-01

Notwithstanding the dramatically increasing frequency of acts of terrorism in Europe and the extent of their media coverage, there is lack of knowledge on people's affective reactions and associated emotion regulation strategies. We explored the affective impact on two cohorts of Italian students (n = 193) possibly exposed vicariously through the mass media to the 2015 Paris or the 2016 Brussels terrorist attacks, respectively. We accessed data from three online questionnaires: one on emotion regulation administered before each attack; one on daily affect administered just before and after each attack; and one on causes of weekly affect and life satisfaction administered at the end of the week in which each attack occurred. The attacks were perceived as relevant for influencing negative affect for 22% of the students. For them, suppression-less frequently used than reappraisal-was associated with an improvement of affect after each attack but negatively related to life satisfaction concerning the week in which the attacks occurred. Our data showed that the recent terrorist attacks occurring in Europe had an affective impact on people at some distance who were vicariously exposed and point to the protective role of emotion regulation as a key resource for individuals' well-being. Copyright © 2017 John Wiley & Sons, Ltd.

Fear of Terrorism in New York After the September 11 Terrorist Attacks: Implications for Emergency Mental Health and Preparedness

PubMed Central

Boscarino, Joseph A.; Figley, Charles R.; Adams, Richard E.

2009-01-01

To examine the public’s response to future terrorist attacks, we surveyed 1,001 New Yorkers in the community one year after the September 11 attacks. Overall, New Yorkers were very concerned about future terrorist attacks and also concerned about attacks involving biological or nuclear weapons. In addition, while most New Yorkers reported that if a biological or nuclear attack occurred they would evaluate available information before evacuating, a significant number reported they would immediately evacuate, regardless of police or public health communications to the contrary. The level of public concern was significantly higher on all measures among New York City and Long Island residents (downstate) compared to the rest of the state. A model predicting higher fear of terrorism indicated that downstate residents, women, those 45 to 64 years old, African Americans and Hispanics, those with less education/income, and those more likely to flee, were more fearful of future attacks. In addition, making disaster preparations and carefully evaluating emergency information also predicted a higher level of fear as well. A second model predicting who would flee suggested that those more likely to evaluate available information were less likely to immediately evacuate, while those with a higher fear of future attacks were more likely to flee the area. Given these findings and the possibility of future attacks, mental health professionals need to be more involved in preparedness efforts, especially related to the psychological impact of attacks involving weapons of mass destruction. PMID:14730761

Ethanol injection of ornamental trees facilitates testing insecticide efficacy against ambrosia beetles (Coleoptera: Curculionidae: Scolytinae).

PubMed

Reding, Michael E; Oliver, Jason B; Schultz, Peter B; Ranger, Christopher M; Youssef, Nadeer N

2013-02-01

Exotic ambrosia beetles are damaging pests in ornamental tree nurseries in North America. The species Xylosandrus crassiusculus (Motshulsky) and Xylosandrus germanus (Blandford) are especially problematic. Management of these pests relies on preventive treatments of insecticides. However, field tests of recommended materials on nursery trees have been limited because of unreliable attacks by ambrosia beetles on experimental trees. Ethanol-injection of trees was used to induce colonization by ambrosia beetles to evaluate insecticides and botanical formulations for preventing attacks by ambrosia beetles. Experiments were conducted in Ohio, Tennessee, and Virginia. Experimental trees injected with ethanol had more attacks by ambrosia beetles than uninjected control trees in all but one experiment. Xylosandrus crassiusculus and X. germanus colonized trees injected with ethanol. In most experiments, attack rates declined 8 d after ethanol-injection. Ethanol-injection induced sufficient pressure from ambrosia beetles to evaluate the efficacy of insecticides for preventing attacks. Trunk sprays of permethrin suppressed cumulative total attacks by ambrosia beetles in most tests. Trunk sprays of the botanical formulations Armorex and Veggie Pharm suppressed cumulative total attacks in Ohio. Armorex, Armorex + Permethrin, and Veggie Pharm + Permethrin suppressed attacks in Tennessee. The bifenthrin product Onyx suppressed establishment of X. germanus in one Ohio experiment, and cumulative total ambrosia beetle attacks in Virginia. Substrate drenches and trunk sprays of neonicotinoids, or trunk sprays of anthranilic diamides or tolfenpyrad were not effective. Ethanol-injection is effective for inducing attacks and ensuring pressure by ambrosia beetles for testing insecticide efficacy on ornamental trees.

Do Unexpected Panic Attacks Occur Spontaneously?

PubMed Central

Meuret, Alicia E.; Rosenfield, David; Wilhelm, Frank H.; Zhou, Enlu; Conrad, Ansgar; Ritz, Thomas; Roth, Walton T.

2012-01-01

Background Spontaneous or unexpected panic attacks, per definition, occur out-of-the blue, in absence of cues or triggers. Accordingly, physiological arousal or instability should occur at the onset of or during the attack, but not preceding it. To test this hypothesisweexaminedif points of significant autonomic changes preceded the onset of spontaneous panic attacks. Methods Forty-three panic disorder patients underwent repeated 24-hour ambulatory monitoring. Thirteen naturally panic attacks were recorded during 1,960 hours of monitoring. Minute-by-minute epochs beginning 60 minutes before, and continuing to 10 minutes after, the onset of individual attacks were examined for respiration, heart rate, and skin conductance level. Measures were controlled for physical activity and vocalization, and compared to time matched control periods within the same person. Results Significant patterns of instability across a numberof autonomic and respiratory variables were detected as early as 47 minutes before panic onset. The final minutes prior to onset were dominated by respiratory changes, with significant decreases in tidal volume followed by abrupt PCO2 increases. Panic attack onset was characterized by heart rate and tidal volume increases and a drop in PCO2. Symptom report was consistent with these changes. Skin conductance levels were generally elevated in the hour before and duringthe attacks. Changes in the matched control periods were largely absent. Conclusions Significant autonomic irregularities preceded the onset of attacks that were reported as abrupt and unexpected. The findings invite reconsideration of the current diagnostic distinction betweenuncuedand cued panic attacks. PMID:21783179

Insecurity of Wireless Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheldon, Frederick T; Weber, John Mark; Yoo, Seong-Moo

Wireless is a powerful core technology enabling our global digital infrastructure. Wi-Fi networks are susceptible to attacks on Wired Equivalency Privacy, Wi-Fi Protected Access (WPA), and WPA2. These attack signatures can be profiled into a system that defends against such attacks on the basis of their inherent characteristics. Wi-Fi is the standard protocol for wireless networks used extensively in US critical infrastructures. Since the Wired Equivalency Privacy (WEP) security protocol was broken, the Wi-Fi Protected Access (WPA) protocol has been considered the secure alternative compatible with hardware developed for WEP. However, in November 2008, researchers developed an attack on WPA,more » allowing forgery of Address Resolution Protocol (ARP) packets. Subsequent enhancements have enabled ARP poisoning, cryptosystem denial of service, and man-in-the-middle attacks. Open source systems and methods (OSSM) have long been used to secure networks against such attacks. This article reviews OSSMs and the results of experimental attacks on WPA. These experiments re-created current attacks in a laboratory setting, recording both wired and wireless traffic. The article discusses methods of intrusion detection and prevention in the context of cyber physical protection of critical Internet infrastructure. The basis for this research is a specialized (and undoubtedly incomplete) taxonomy of Wi-Fi attacks and their adaptations to existing countermeasures and protocol revisions. Ultimately, this article aims to provide a clearer picture of how and why wireless protection protocols and encryption must achieve a more scientific basis for detecting and preventing such attacks.« less

Fear of terrorism in New York after the September 11 terrorist attacks: implications for emergency mental health and preparedness.

PubMed

Boscarino, Joseph A; Figley, Charles R; Adams, Richard E

2003-01-01

To examine the public's response to future terrorist attacks, we surveyed 1,001 New Yorkers in the community one year after the September 11 attacks. Overall, New Yorkers were very concerned about future terrorist attacks and also concerned about attacks involving biological or nuclear weapons. In addition, while most New Yorkers reported that if a biological or nuclear attack occurred they would evaluate available information before evacuating, a significant number reported they would immediately evacuate, regardless of police or public health communications to the contrary. The level of public concern was significantly higher on all measures among New York City and Long Island residents (downstate) compared to the rest of the state. A model predicting higher fear of terrorism indicated that downstate residents, women, those 45 to 64 years old, African Americans and Hispanics, those with less education/income, and those more likely to flee, were more fearful of future attacks. In addition, making disaster preparations and carefully evaluating emergency information also predicted a higher level of fear as well. A second model predicting who would flee suggested that those more likely to evaluate available information were less likely to immediately evacuate, while those with a higher fear of future attacks were more likely to flee the area. Given these findings and the possibility of future attacks, mental health professionals need to be more involved in preparedness efforts, especially related to the psychological impact of attacks involving weapons of mass destruction.

Metrics for Assessment of Smart Grid Data Integrity Attacks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annarita Giani; Miles McQueen; Russell Bent

2012-07-01

There is an emerging consensus that the nation’s electricity grid is vulnerable to cyber attacks. This vulnerability arises from the increasing reliance on using remote measurements, transmitting them over legacy data networks to system operators who make critical decisions based on available data. Data integrity attacks are a class of cyber attacks that involve a compromise of information that is processed by the grid operator. This information can include meter readings of injected power at remote generators, power flows on transmission lines, and relay states. These data integrity attacks have consequences only when the system operator responds to compromised datamore » by redispatching generation under normal or contingency protocols. These consequences include (a) financial losses from sub-optimal economic dispatch to service loads, (b) robustness/resiliency losses from placing the grid at operating points that are at greater risk from contingencies, and (c) systemic losses resulting from cascading failures induced by poor operational choices. This paper is focused on understanding the connections between grid operational procedures and cyber attacks. We first offer two examples to illustrate how data integrity attacks can cause economic and physical damage by misleading operators into taking inappropriate decisions. We then focus on unobservable data integrity attacks involving power meter data. These are coordinated attacks where the compromised data are consistent with the physics of power flow, and are therefore passed by any bad data detection algorithm. We develop metrics to assess the economic impact of these attacks under re-dispatch decisions using optimal power flow methods. These metrics can be use to prioritize the adoption of appropriate countermeasures including PMU placement, encryption, hardware upgrades, and advance attack detection algorithms.« less

Prediction of first episode of panic attack among white-collar workers.

PubMed

Watanabe, Akira; Nakao, Kazuhisa; Tokuyama, Madoka; Takeda, Masatoshi

2005-04-01

The purpose of the present study was to elucidate a longitudinal matrix of the etiology for first-episode panic attack among white-collar workers. A path model was designed for this purpose. A 5-year, open-cohort study was carried out in a Japanese company. To evaluate the risk factors associated with the onset of a first episode of panic attack, the odds ratios of a new episode of panic attack were calculated by logistic regression. The path model contained five predictor variables: gender difference, overprotection, neuroticism, lifetime history of major depression, and recent stressful life events. The logistic regression analysis indicated that a person with a lifetime history of major depression and recent stressful life events had a fivefold and a threefold higher risk of panic attacks at follow up, respectively. The path model for the prediction of a first episode of panic attack fitted the data well. However, this model presented low accountability for the variance in the ultimate dependent variables, the first episode of panic attack. Three predictors (neuroticism, lifetime history of major depression, and recent stressful life events) had a direct effect on the risk for a first episode of panic attack, whereas gender difference and overprotection had no direct effect. The present model could not fully predict first episodes of panic attack in white-collar workers. To make a path model for the prediction of the first episode of panic attack, other strong predictor variables, which were not surveyed in the present study, are needed. It is suggested that genetic variables are among the other strong predictor variables. A new path model containing genetic variables (e.g. family history etc.) will be needed to predict the first episode of panic attack.

Dopaminergic regulation of sleep and cataplexy in a murine model of narcolepsy.

PubMed

Burgess, Christian R; Tse, Gavin; Gillis, Lauren; Peever, John H

2010-10-01

To determine if the dopaminergic system modulates cataplexy, sleep attacks and sleep-wake behavior in narcoleptic mice. Hypocretin/orexin knockout (i.e., narcoleptic) and wild-type mice were administered amphetamine and specific dopamine receptor modulators to determine their effects on sleep, cataplexy and sleep attacks. Hypocretin knockout (n = 17) and wild-type mice (n = 21). Cataplexy, sleep attacks and sleep-wake behavior were identified using electroencephalogram, electromyogram and videography. These behaviors were monitored for 4 hours after an i.p. injection of saline, amphetamine and specific dopamine receptor modulators (D1- and D2-like receptor modulators). Amphetamine (2 mg/kg), which increases brain dopamine levels, decreased sleep attacks and cataplexy by 61% and 67%, suggesting that dopamine transmission modulates such behaviors. Dopamine receptor modulation also had powerful effects on sleep attacks and cataplexy. Activation (SKF 38393; 20 mg/kg) and blockade (SCH 23390; 1 mg/kg) of D1-like receptors decreased and increased sleep attacks by 77% and 88%, without affecting cataplexy. Pharmacological activation of D2-like receptors (quinpirole; 0.5 mg/kg) increased cataplectic attacks by 172% and blockade of these receptors (eticlopride; 1 mg/kg) potently suppressed them by 97%. Manipulation of D2-like receptors did not affect sleep attacks. We show that the dopaminergic system plays a role in regulating both cataplexy and sleep attacks in narcoleptic mice. We found that cataplexy is modulated by a D2-like receptor mechanism, whereas dopamine modulates sleep attacks by a D1-like receptor mechanism. These results support a role for the dopamine system in regulating sleep attacks and cataplexy in a murine model of narcolepsy.

Economic burden of gouty arthritis attacks for employees with frequent and infrequent attacks.

PubMed

Lynch, Wendy; Chan, Wing; Kleinman, Nathan; Andrews, L M; Yadao, Anthony M

2013-04-01

The objective of this study was to compare episode-related and annual costs and work absence days for employees with <3 versus ≥ 3 annual gout attacks. Human Capital Management Services data (2009-2010) from adult employees with gout (International Classification of Diseases, Ninth Revision code 274.x) and ≥ 12 months of medical and pharmacy benefits were studied. Outcomes of interest included medical and drug costs, number of emergency department and urgent care visits, number of inpatient days, short- and long-term disability, sick leave, workers' compensation costs, and work absence days. An algorithm based on diagnosis code and antigout medication use identified acute gout treatment episodes. Multivariate analysis compared annual and pre-episode vs. during-episode outcomes for employees with ≥ 3 vs. <3 gout annual attacks. Of 3361 employees with gout, 76 had ≥ 3 attacks; these employees had higher short-term disability costs ($1663 vs. $643, P=0.06) and days (11.68 versus 4.61, P<0.05), more emergency room visits (0.55 vs. 0.23, P<0.0001), and urgent care visits (0.07 vs. 0.04, P<0.01), and lower pharmacy costs ($1677 vs. $1108, P<0.0001) than those with <3 attacks. Medical costs both before ($203 higher) and during attacks ($136 higher) were significantly higher for those with ≥ 3 attacks than for those with <3 attacks. Additionally, a quadratic increasing relationship was found between number of attacks and cost. Frequency of acute gout attacks (≥ 3 episodes per year) among employees with gout was associated with greater short-term disability cost, absence days, and emergency department and urgent care visits, and trends toward higher overall costs.

Correlation of forebody pressures and aircraft yawing moments on the X-29A aircraft at high angles of attack

NASA Technical Reports Server (NTRS)

Fisher, David F.; Richwine, David M.; Landers, Stephen

1992-01-01

In-flight pressure distributions at four fuselage stations on the forebody of the X-29A aircraft have been reported at angles of attack from 15 to 66 deg and at Mach numbers from 0.22 to 0.60. At angles of attack of 20 deg and higher, vortices shed from the nose strake caused suction peaks in the pressure distributions that generally increased in magnitude with angle of attack. Above 30 deg-angle of attack, the forebody pressure distributions became asymmetrical at the most forward station, while they remained nearly symmetrical until 50 to 55 deg-angle of attack for the aft stations. Between 59 to 66 deg-angle of attack, the asymmetry of the pressure distributions changed direction. Yawing moments for the forebody alone were obtained by integrating the forebody pressure distributions. At 45 deg-angle of attack, the aircraft yaws to the right and at 50 deg and higher, the aircraft yaws to the left. The forebody yawing moments correlated well with the aircraft left yawing moment at an angle of attack of 50 deg or higher. At a 45 deg-angle of attack, the forebody yawing moments did not correlate well with the aircraft yawing moment, but it is suggested that this was due to asymmetric pressures on the cockpit region of the fuselage which was not instrumented. The forebody was also shown to provide a positive component of directional stability of the aircraft at angles of attack of 25 deg or higher. A Mach number effect was noted at angles of attack of 30 deg or higher at the station where the nose strake was present. At this station, the suction peaks in the pressure distributions at the highest Mach number were reduced and much more symmetrical as compared to the lower Mach number pressure distributions.

EVALUATION OF THE CHANGES IN THE NASAL CAVITY DURING THE MIGRAINE ATTACK

PubMed Central

Arslan, H. Hüseyin; Tokgöz, Erkan; Yıldızoğlu, Üzeyir; Durmaz, Abdullah; Bek, Semai; Gerek, Mustafa

2012-01-01

Objectives There are some subjective symptoms involving the nasal cavity such as nasal congestion during a migraine attack. In this study, we aimed to evaluate the possible changes occuring in the nasal cavity, during headache in migraine patients. Material and Methods Subjects with migraine were studied. The control group was consisted with tension-type headache patients. The severity of the headache and accompanying complaints were assessed by visual analog scale, and nasal mucosa was assessed by anterior rhinoscopy and endoscopy. Resistance of the nasal cavity was evaluated with anterior rhinomanometry. The data obtained during the attack periods and attack free periods were compared. Results 25 migraine patients and 15 tension-type headache patients were enrolled. It was found that 19 subjects (%76) of migraine group and 5 of tension-type headache group were suffering from nasal congestion during the attack, and that the differences between the groups were statistically significant (p<0.05). The average of total nasal resistance in migraine patients was 0,57±0,60 kPa/L/sn during migraine attacks and 0,28±0,14 kPa/L/sn during attack free periods. The average of total nasal resistance in tension-type headache patients was 0,32±0,14 kPa/L/sn during attack periods and 0,31±0,20 kPa/L/sn during attack free periods. In the migraine group, the change of nasal resistance between during the attack and attack free periods was found statistically significant, while there was no statistically significant difference in the tension-type headache group. Conclusion According to the results of this study, complaining of nasal obstruction and nasal airway resistance increases during migraine attacks. Cause and effect relationship between nasal obstruction and pain is not clear and clinical trials are needed to determine the effect of nasal obstruction treatment (mucosal decongestion etc.) on the complaint of pain. PMID:25072974

Dead or Alive? Factors Affecting the Survival of Victims during Attacks by Saltwater Crocodiles (Crocodylus porosus) in Australia.

PubMed

Fukuda, Yusuke; Manolis, Charlie; Saalfeld, Keith; Zuur, Alain

2015-01-01

Conflicts between humans and crocodilians are a widespread conservation challenge and the number of crocodile attacks is increasing worldwide. We identified the factors that most effectively decide whether a victim is injured or killed in a crocodile attack by fitting generalized linear models to a 42-year dataset of 87 attacks (27 fatal and 60 non-fatal) by saltwater crocodiles (Crocodylus porosus) in Australia. The models showed that the most influential factors were the difference in body mass between crocodile and victim, and the position of victim in relation to the water at the time of an attack. In-water position (for diving, swimming, and wading) had a higher risk than on-water (boating) or on-land (fishing, and hunting near the water's edge) positions. In the in-water position a 75 kg person would have a relatively high probability of survival (0.81) if attacked by a 300 cm crocodile, but the probability becomes much lower (0.17) with a 400 cm crocodile. If attacked by a crocodile larger than 450 cm, the survival probability would be extremely low (<0.05) regardless of the victim's size. These results indicate that the main cause of death during a crocodile attack is drowning and larger crocodiles can drag a victim more easily into deeper water. A higher risk associated with a larger crocodile in relation to victim's size is highlighted by children's vulnerability to fatal attacks. Since the first recently recorded fatal attack involving a child in 2006, six out of nine fatal attacks (66.7%) involved children, and the average body size of crocodiles responsible for these fatal attacks was considerably smaller (384 cm, 223 kg) than that of crocodiles that killed adults (450 cm, 324 kg) during the same period (2006-2014). These results suggest that culling programs targeting larger crocodiles may not be an effective management option to improve safety for children.

Dead or Alive? Factors Affecting the Survival of Victims during Attacks by Saltwater Crocodiles (Crocodylus porosus) in Australia

PubMed Central

Fukuda, Yusuke

2015-01-01

Conflicts between humans and crocodilians are a widespread conservation challenge and the number of crocodile attacks is increasing worldwide. We identified the factors that most effectively decide whether a victim is injured or killed in a crocodile attack by fitting generalized linear models to a 42-year dataset of 87 attacks (27 fatal and 60 non-fatal) by saltwater crocodiles (Crocodylus porosus) in Australia. The models showed that the most influential factors were the difference in body mass between crocodile and victim, and the position of victim in relation to the water at the time of an attack. In-water position (for diving, swimming, and wading) had a higher risk than on-water (boating) or on-land (fishing, and hunting near the water's edge) positions. In the in-water position a 75 kg person would have a relatively high probability of survival (0.81) if attacked by a 300 cm crocodile, but the probability becomes much lower (0.17) with a 400 cm crocodile. If attacked by a crocodile larger than 450 cm, the survival probability would be extremely low (<0.05) regardless of the victim’s size. These results indicate that the main cause of death during a crocodile attack is drowning and larger crocodiles can drag a victim more easily into deeper water. A higher risk associated with a larger crocodile in relation to victim’s size is highlighted by children’s vulnerability to fatal attacks. Since the first recently recorded fatal attack involving a child in 2006, six out of nine fatal attacks (66.7%) involved children, and the average body size of crocodiles responsible for these fatal attacks was considerably smaller (384 cm, 223 kg) than that of crocodiles that killed adults (450 cm, 324 kg) during the same period (2006–2014). These results suggest that culling programs targeting larger crocodiles may not be an effective management option to improve safety for children. PMID:25961294

Review of attacks on health care facilities in six conflicts of the past three decades.

PubMed

Briody, Carolyn; Rubenstein, Leonard; Roberts, Les; Penney, Eamon; Keenan, William; Horbar, Jeffrey

2018-01-01

In the ongoing conflicts of Syria and Yemen, there have been widespread reports of attacks on health care facilities and personnel. Tabulated evidence does suggest hospital bombings in Syria and Yemen are far higher than reported in other conflicts but it is unclear if this is a reporting artefact. This article examines attacks on health care facilities in conflicts in six middle- to high- income countries that have occurred over the past three decades to try and determine if attacks have become more common, and to assess the different methods used to collect data on attacks. The six conflicts reviewed are Yemen (2015-Present), Syria (2011- Present), Iraq (2003-2011), Chechnya (1999-2000), Kosovo (1998-1999), and Bosnia and Herzegovina (1992-1995). We attempted to get the highest quality source(s) with summary data of the number of facilities attacked for each of the conflicts. The only conflict that did not have summary data was the conflict in Iraq. In this case, we tallied individual reported events of attacks on health care. Physicians for Human Rights (PHR) reported attacks on 315 facilities (4.38 per month) in Syria over a 7-year period, while the Monitoring Violence against Health Care (MVH) tool launched later by the World Health Organization (WHO) Turkey Health Cluster reported attacks on 135 facilities (9.64 per month) over a 14-month period. Yemen had a reported 93 attacks (4.65 per month), Iraq 12 (0.12 per month), Chechnya > 24 (2.4 per month), Kosovo > 100 (6.67 per month), and Bosnia 21 (0.41 per month). Methodologies to collect data, and definitions of both facilities and attacks varied widely across sources. The number of reported facilities attacked is by far the greatest in Syria, suggesting that this phenomenon has increased compared to earlier conflicts. However, data on attacks of facilities was incomplete for all of the conflicts examined, methodologies varied widely, and in some cases, attacks were not defined at all. A global, standardized system that allows multiple reporting routes with different levels of confirmation, as seen in Syria, would likely allow for a more reliable and reproducible documentation system, and potentially, an increase in accountability.

Wounding patterns and human performance in knife attacks: optimising the protection provided by knife-resistant body armour.

PubMed

Bleetman, A; Watson, C H; Horsfall, I; Champion, S M

2003-12-01

Stab attacks generate high loads, and to defeat them, armour needs to be of a certain thickness and stiffness. Slash attacks produce much lower loads and armour designed to defeat them can be far lighter and more flexible. Phase 1: Human performance in slash attacks: 87 randomly selected students at the Royal Military College of Science were asked to make one slash attack with an instrumented blade on a vertically mounted target. No instructions on how to slash the target were given. The direction, contact forces and velocity of each attack were recorded. Phase 2: Clinical experience with edged weapon attacks: The location and severity of all penetrating injuries in patients attending the Glasgow Royal Infirmary between 1993 and 1996 were charted on anatomical figures. Phase 1: Two types of human slash behaviour were evident: a 'chop and drag' blow and a 'sweep motion' type of attack. 'Chop and drag' attacks had higher peak forces and velocities than sweep attacks. Shoulder to waist blows (diagonal) accounted for 82% of attacks, 71% of attackers used a long diagonal slash with an average cut length of 34 cm and 11% used short diagonal attacks with an average cut length of 25 cm. Only 18% of attackers slashed across the body (short horizontal); the average measured cut length of this type was 28 cm. The maximum peak force for the total sample population was 212 N; the maximum velocity was 14.88 m s(-1). The 95 percentile force for the total sample population was 181 N and the velocity was 9.89 m s(-1). Phase 2: 431 of the 500 patients had been wounded with edged weapons. The average number of wounds sustained by victims in knife assaults was 2.4. The distribution of wounds by frequency and severity are presented. Anti-slash protection is required for the arms, neck, shoulders, and thighs. The clinical experience of knife-attack victims provides information on the relative vulnerabilities of different regions of the body. It is anticipated that designing a tunic-type of Police uniform that is inherently stab and slash resistant will eventually replace the current obvious and often bulky extra protective vest. Attempts at making a combined garment will need to be guided by ergonomic considerations and field testing. A similar anatomical regional risk model might also be appropriate in the design of anti-ballistic armour and combined anti-ballistic and knife-resistant armour.

Determining the scope of attacks on health in four governorates of Syria in 2016: Results of a field surveillance program

PubMed Central

Risko, Casey B.; Rayes, Diana; Albaik, Ahmad; Alnajar, Mohammed; Kewara, Mazen; Baker, Elise; Rubenstein, Leonard S.

2018-01-01

Background Violent attacks on and interferences with hospitals, ambulances, health workers, and patients during conflict destroy vital health services during a time when they are most needed and undermine the long-term capacity of the health system. In Syria, such attacks have been frequent and intense and represent grave violations of the Geneva Conventions, but the number reported has varied considerably. A systematic mechanism to document these attacks could assist in designing more protection strategies and play a critical role in influencing policy, promoting justice, and addressing the health needs of the population. Methods and findings We developed a mobile data collection questionnaire to collect data on incidents of attacks on healthcare directly from the field. Data collectors from the Syrian American Medical Society (SAMS), using the tool or a text messaging system, recorded information on incidents across four of Syria’s northern governorates (Aleppo, Idleb, Hama, and Homs) from January 1, 2016, to December 31, 2016. SAMS recorded a total of 200 attacks on healthcare in 2016, 102 of them using the mobile data collection tool. Direct attacks on health facilities comprised the majority of attacks recorded (88.0%; n = 176). One hundred and twelve healthcare staff and 185 patients were killed in these incidents. Thirty-five percent of the facilities were attacked more than once over the data collection period; hospitals were significantly more likely to be attacked more than once compared to clinics and other types of healthcare facilities. Aerial bombs were used in the overwhelming majority of cases (91.5%). We also compared the SAMS data to a separate database developed by Physicians for Human Rights (PHR) based on media reports and matched the incidents to compare the results from the two methods (this analysis was limited to incidents at health facilities). Among 90 relevant incidents verified by PHR and 177 by SAMS, there were 60 that could be matched to each other, highlighting the differences in results from the two methods. This study is limited by the complexities of data collection in a conflict setting, only partial use of the standardized reporting tool, and the fact that limited accessibility of some health facilities and workers and may be biased towards the reporting of attacks on larger or more visible health facilities. Conclusions The use of field data collectors and use of consistent definitions can play an important role in the tracking incidents of attacks on health services. A mobile systematic data collection tool can complement other methods for tracking incidents of attacks on healthcare and ensure the collection of detailed information about each attack that may assist in better advocacy, programs, and accountability but can be practically challenging. Comparing attacks between SAMS and PHR suggests that there may have been significantly more attacks than previously captured by any one methodology. This scale of attacks suggests that targeting of healthcare in Syria is systematic and highlights the failure of condemnation by the international community and medical groups working in Syria of such attacks to stop them. PMID:29689085

Douglas-fir beetle attack and tree mortality following wildfire

Treesearch

Sharon M. Hood; Barbara Bentz; Kevin C. Ryan

2003-01-01

A major concern after wildfires is the buildup of bark beetle populations in fire injured trees, and subsequent attack and population buildup in adjacent unburned areas. To examine this concern, we documented fire injury and insect attacks in Douglas-fir (Pseudotsuga menziesii) on the 2001 Green Knoll Fire, Wyoming to determine attack preferences, brood production, and...

The Effects of Denial-of-Service Attacks on Secure Time-Critical Communications in the Smart Grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Fengli; Li, QInghua; Mantooth, Homer Alan

2016-04-02

According to IEC 61850, many smart grid communications require messages to be delivered in a very short time. –Trip messages and sample values applied to the transmission level: 3 ms –Interlocking messages applied to the distribution level: 10 ms •Time-critical communications are vulnerable to denial-of-service (DoS) attacks –Flooding attack: Attacker floods many messages to the target network/machine. We conducted systematic, experimental study about how DoS attacks affect message delivery delays.

The maul of the wild. Animal attacks can produce significant trauma.

PubMed

Conrad, L

1994-03-01

Wild-animal attacks are almost an anachronism in our day and age. They remind us that humans can still be food or prey. Cougar attacks, though rare, produce significant trauma. Characteristic patterns of injury and wound infection should be appropriately identified and treated. As we protect wild-animal species and acknowledge their right to share territory, interactions--and possibly attacks--are likely to increase. Awareness, education, knowledge and prevention, rather than the elimination of animal populations, may be the best way to control wild-animal attacks on humans in the future.

Attacks and intrusion detection in wireless sensor networks of industrial SCADA systems

NASA Astrophysics Data System (ADS)

Kamaev, V. A.; Finogeev, A. G.; Finogeev, A. A.; Parygin, D. S.

2017-01-01

The effectiveness of automated process control systems (APCS) and supervisory control and data acquisition systems (SCADA) information security depends on the applied protection technologies of transport environment data transmission components. This article investigates the problems of detecting attacks in wireless sensor networks (WSN) of SCADA systems. As a result of analytical studies, the authors developed the detailed classification of external attacks and intrusion detection in sensor networks and brought a detailed description of attacking impacts on components of SCADA systems in accordance with the selected directions of attacks.

SFTP: A Secure and Fault-Tolerant Paradigm against Blackhole Attack in MANET

NASA Astrophysics Data System (ADS)

KumarRout, Jitendra; Kumar Bhoi, Sourav; Kumar Panda, Sanjaya

2013-02-01

Security issues in MANET are a challenging task nowadays. MANETs are vulnerable to passive attacks and active attacks because of a limited number of resources and lack of centralized authority. Blackhole attack is an attack in network layer which degrade the network performance by dropping the packets. In this paper, we have proposed a Secure Fault-Tolerant Paradigm (SFTP) which checks the Blackhole attack in the network. The three phases used in SFTP algorithm are designing of coverage area to find the area of coverage, Network Connection algorithm to design a fault-tolerant model and Route Discovery algorithm to discover the route and data delivery from source to destination. SFTP gives better network performance by making the network fault free.

Panic disorder, panic attacks and panic attack symptoms across race-ethnic groups: results of the collaborative psychiatric epidemiology studies.

PubMed

Asnaani, Anu; Gutner, Cassidy A; Hinton, Devon E; Hofmann, Stefan G

2009-01-01

The current study investigates race-ethnic differences in rates of panic disorder, panic attacks and certain panic attack symptoms by jointly combining three major national epidemiological databases. The compared groups were White, African American, Latino and Asian. The White group had significantly higher rates of panic disorder, and of many panic symptoms, including palpitations, as compared to the African American, Asian and Latino groups. Several expected race-ethnic differences were not found. An explanation for these findings are adduced, and suggestions are given for future studies so that possible ethnic-racial differences in panic disorder, panic attacks and panic attack symptoms can be investigated in a more rigorous manner.

A Learning-Based Approach to Reactive Security

NASA Astrophysics Data System (ADS)

Barth, Adam; Rubinstein, Benjamin I. P.; Sundararajan, Mukund; Mitchell, John C.; Song, Dawn; Bartlett, Peter L.

Despite the conventional wisdom that proactive security is superior to reactive security, we show that reactive security can be competitive with proactive security as long as the reactive defender learns from past attacks instead of myopically overreacting to the last attack. Our game-theoretic model follows common practice in the security literature by making worst-case assumptions about the attacker: we grant the attacker complete knowledge of the defender's strategy and do not require the attacker to act rationally. In this model, we bound the competitive ratio between a reactive defense algorithm (which is inspired by online learning theory) and the best fixed proactive defense. Additionally, we show that, unlike proactive defenses, this reactive strategy is robust to a lack of information about the attacker's incentives and knowledge.

Network Security Risk Assessment System Based on Attack Graph and Markov Chain

NASA Astrophysics Data System (ADS)

Sun, Fuxiong; Pi, Juntao; Lv, Jin; Cao, Tian

2017-10-01

Network security risk assessment technology can be found in advance of the network problems and related vulnerabilities, it has become an important means to solve the problem of network security. Based on attack graph and Markov chain, this paper provides a Network Security Risk Assessment Model (NSRAM). Based on the network infiltration tests, NSRAM generates the attack graph by the breadth traversal algorithm. Combines with the international standard CVSS, the attack probability of atomic nodes are counted, and then the attack transition probabilities of ones are calculated by Markov chain. NSRAM selects the optimal attack path after comprehensive measurement to assessment network security risk. The simulation results show that NSRAM can reflect the actual situation of network security objectively.

Attacks on Bluetooth Security Architecture and Its Countermeasures

NASA Astrophysics Data System (ADS)

Iqbal, Mian Muhammad Waseem; Kausar, Firdous; Wahla, Muhammad Arif

WPANs compliment the traditional IEEE 802.11 wireless networks by facilitating the clients with flexibility in network topologies, higher mobility and relaxed configuration/hardware requirements. Bluetooth, a WPAN technology, is an open standard for short-range radio frequency (RF) communication. However, it is also susceptible to typical security threats found in wireless LANs. This paper discuses some of the attack scenarios against the bluetooth network such as hostile intrusion, active Man-in-the-Middle (MITM) attack using unit key and various forms of denial of service (DoS) attacks. These threats and attacks compromise the confidentiality and availability of bluetooth data and services. This paper proposes an improved security architecture for bluetooth device which provides protection against the above mentioned attacks.

Design and implementation of dynamic hybrid Honeypot network

NASA Astrophysics Data System (ADS)

Qiao, Peili; Hu, Shan-Shan; Zhai, Ji-Qiang

2013-05-01

The method of constructing a dynamic and self-adaptive virtual network is suggested to puzzle adversaries, delay and divert attacks, exhaust attacker resources and collect attacking information. The concepts of Honeypot and Honeyd, which is the frame of virtual Honeypot are introduced. The techniques of network scanning including active fingerprint recognition are analyzed. Dynamic virtual network system is designed and implemented. A virtual network similar to real network topology is built according to the collected messages from real environments in this system. By doing this, the system can perplex the attackers when Hackers attack and can further analyze and research the attacks. The tests to this system prove that this design can successfully simulate real network environment and can be used in network security analysis.

A Novel Protective Framework for Defeating HTTP-Based Denial of Service and Distributed Denial of Service Attacks.

PubMed

Saleh, Mohammed A; Abdul Manaf, Azizah

2015-01-01

The growth of web technology has brought convenience to our life, since it has become the most important communication channel. However, now this merit is threatened by complicated network-based attacks, such as denial of service (DoS) and distributed denial of service (DDoS) attacks. Despite many researchers' efforts, no optimal solution that addresses all sorts of HTTP DoS/DDoS attacks is on offer. Therefore, this research aims to fix this gap by designing an alternative solution called a flexible, collaborative, multilayer, DDoS prevention framework (FCMDPF). The innovative design of the FCMDPF framework handles all aspects of HTTP-based DoS/DDoS attacks through the following three subsequent framework's schemes (layers). Firstly, an outer blocking (OB) scheme blocks attacking IP source if it is listed on the black list table. Secondly, the service traceback oriented architecture (STBOA) scheme is to validate whether the incoming request is launched by a human or by an automated tool. Then, it traces back the true attacking IP source. Thirdly, the flexible advanced entropy based (FAEB) scheme is to eliminate high rate DDoS (HR-DDoS) and flash crowd (FC) attacks. Compared to the previous researches, our framework's design provides an efficient protection for web applications against all sorts of DoS/DDoS attacks.

A Novel Protective Framework for Defeating HTTP-Based Denial of Service and Distributed Denial of Service Attacks

PubMed Central

Saleh, Mohammed A.; Abdul Manaf, Azizah

2015-01-01

The growth of web technology has brought convenience to our life, since it has become the most important communication channel. However, now this merit is threatened by complicated network-based attacks, such as denial of service (DoS) and distributed denial of service (DDoS) attacks. Despite many researchers' efforts, no optimal solution that addresses all sorts of HTTP DoS/DDoS attacks is on offer. Therefore, this research aims to fix this gap by designing an alternative solution called a flexible, collaborative, multilayer, DDoS prevention framework (FCMDPF). The innovative design of the FCMDPF framework handles all aspects of HTTP-based DoS/DDoS attacks through the following three subsequent framework's schemes (layers). Firstly, an outer blocking (OB) scheme blocks attacking IP source if it is listed on the black list table. Secondly, the service traceback oriented architecture (STBOA) scheme is to validate whether the incoming request is launched by a human or by an automated tool. Then, it traces back the true attacking IP source. Thirdly, the flexible advanced entropy based (FAEB) scheme is to eliminate high rate DDoS (HR-DDoS) and flash crowd (FC) attacks. Compared to the previous researches, our framework's design provides an efficient protection for web applications against all sorts of DoS/DDoS attacks. PMID:26065015

Effectiveness of the call in beach volleyball attacking play.

PubMed

Künzell, Stefan; Schweikart, Florian; Köhn, Daniel; Schläppi-Lienhard, Olivia

2014-12-09

In beach volleyball the setter has the opportunity to give her or his hitter a "call". The call intends that the setter suggests to her or his partner where to place the attack in the opponent's court. The effectiveness of a call is still unknown. We investigated the women's and men's Swiss National Beach Volleyball Championships in 2011 and analyzed 2185 attacks. We found large differences between female and male players. While men called in only 38.4% of attacks, women used calls in 85.5% of attacks. If the male players followed a given call, 63% of the attacks were successful. The success rate of attacks without any call was 55.8% and 47.6% when the call was ignored. These differences were not significant (χ(2)(2) = 4.55, p = 0.103). In women's beach volleyball, the rate of successful attacks was 61.5% when a call was followed, 35% for attacks without a call, and 42.6% when a call was ignored. The differences were highly significant (χ(2)(2) = 23.42, p < 0.0005). Taking into account the findings of the present study, we suggested that the call was effective in women's beach volleyball, while its effect in men's game was unclear. Considering the quality of calls we indicate that there is a significant potential to increase the effectiveness of a call.

Practical security and privacy attacks against biometric hashing using sparse recovery

NASA Astrophysics Data System (ADS)

Topcu, Berkay; Karabat, Cagatay; Azadmanesh, Matin; Erdogan, Hakan

2016-12-01

Biometric hashing is a cancelable biometric verification method that has received research interest recently. This method can be considered as a two-factor authentication method which combines a personal password (or secret key) with a biometric to obtain a secure binary template which is used for authentication. We present novel practical security and privacy attacks against biometric hashing when the attacker is assumed to know the user's password in order to quantify the additional protection due to biometrics when the password is compromised. We present four methods that can reconstruct a biometric feature and/or the image from a hash and one method which can find the closest biometric data (i.e., face image) from a database. Two of the reconstruction methods are based on 1-bit compressed sensing signal reconstruction for which the data acquisition scenario is very similar to biometric hashing. Previous literature introduced simple attack methods, but we show that we can achieve higher level of security threats using compressed sensing recovery techniques. In addition, we present privacy attacks which reconstruct a biometric image which resembles the original image. We quantify the performance of the attacks using detection error tradeoff curves and equal error rates under advanced attack scenarios. We show that conventional biometric hashing methods suffer from high security and privacy leaks under practical attacks, and we believe more advanced hash generation methods are necessary to avoid these attacks.

Defense of Cyber Infrastructures Against Cyber-Physical Attacks Using Game-Theoretic Models

DOE PAGES

Rao, Nageswara S. V.; Poole, Stephen W.; Ma, Chris Y. T.; ...

2015-04-06

The operation of cyber infrastructures relies on both cyber and physical components, which are subject to incidental and intentional degradations of different kinds. Within the context of network and computing infrastructures, we study the strategic interactions between an attacker and a defender using game-theoretic models that take into account both cyber and physical components. The attacker and defender optimize their individual utilities expressed as sums of cost and system terms. First, we consider a Boolean attack-defense model, wherein the cyber and physical sub-infrastructures may be attacked and reinforced as individual units. Second, we consider a component attack-defense model wherein theirmore » components may be attacked and defended, and the infrastructure requires minimum numbers of both to function. We show that the Nash equilibrium under uniform costs in both cases is computable in polynomial time, and it provides high-level deterministic conditions for the infrastructure survival. When probabilities of successful attack and defense, and of incidental failures are incorporated into the models, the results favor the attacker but otherwise remain qualitatively similar. This approach has been motivated and validated by our experiences with UltraScience Net infrastructure, which was built to support high-performance network experiments. In conclusion, the analytical results, however, are more general, and we apply them to simplified models of cloud and high-performance computing infrastructures.« less

Quantum hacking: Saturation attack on practical continuous-variable quantum key distribution

NASA Astrophysics Data System (ADS)

Qin, Hao; Kumar, Rupesh; Alléaume, Romain

2016-07-01

We identify and study a security loophole in continuous-variable quantum key distribution (CVQKD) implementations, related to the imperfect linearity of the homodyne detector. By exploiting this loophole, we propose an active side-channel attack on the Gaussian-modulated coherent-state CVQKD protocol combining an intercept-resend attack with an induced saturation of the homodyne detection on the receiver side (Bob). We show that an attacker can bias the excess noise estimation by displacing the quadratures of the coherent states received by Bob. We propose a saturation model that matches experimental measurements on the homodyne detection and use this model to study the impact of the saturation attack on parameter estimation in CVQKD. We demonstrate that this attack can bias the excess noise estimation beyond the null key threshold for any system parameter, thus leading to a full security break. If we consider an additional criterion imposing that the channel transmission estimation should not be affected by the attack, then the saturation attack can only be launched if the attenuation on the quantum channel is sufficient, corresponding to attenuations larger than approximately 6 dB. We moreover discuss the possible countermeasures against the saturation attack and propose a countermeasure based on Gaussian postselection that can be implemented by classical postprocessing and may allow one to distill the secret key when the raw measurement data are partly saturated.

Securing Cooperative Spectrum Sensing Against Collusive SSDF Attack using XOR Distance Analysis in Cognitive Radio Networks

PubMed Central

Feng, Jingyu; Zhang, Man; Xiao, Yun; Yue, Hongzhou

2018-01-01

Cooperative spectrum sensing (CSS) is considered as a powerful approach to improve the utilization of scarce spectrum resources. However, if CSS assumes that all secondary users (SU) are honest, it may offer opportunities for attackers to conduct a spectrum sensing data falsification (SSDF) attack. To suppress such a threat, recent efforts have been made to develop trust mechanisms. Currently, some attackers can collude with each other to form a collusive clique, and thus not only increase the power of SSDF attack but also avoid the detection of a trust mechanism. Noting the duality of sensing data, we propose a defense scheme called XDA from the perspective of XOR distance analysis to suppress a collusive SSDF attack. In the XDA scheme, the XOR distance calculation in line with the type of “0” and “1” historical sensing data is used to measure the similarity between any two SUs. Noting that collusive SSDF attackers hold high trust value and the minimum XOR distance, the algorithm to detect collusive SSDF attackers is designed. Meanwhile, the XDA scheme can perfect the trust mechanism to correct collusive SSDF attackers’ trust value. Simulation results show that the XDA scheme can enhance the accuracy of trust evaluation, and thus successfully reduce the power of collusive SSDF attack against CSS. PMID:29382061

Relation of Temperature and Humidity to the Risk of Recurrent Gout Attacks

PubMed Central

Neogi, Tuhina; Chen, Clara; Niu, Jingbo; Chaisson, Christine; Hunter, David J.; Choi, Hyon; Zhang, Yuqing

2014-01-01

Gout attack risk may be affected by weather (e.g., because of volume depletion). We therefore examined the association of temperature and humidity with the risk of recurrent gout attacks by conducting an internet-based case-crossover study in the United States (in 2003–2010) among subjects with a diagnosis of gout who had 1 or more attacks during 1 year of follow-up. We examined the association of temperature and humidity over the prior 48 hours with the risk of gout attacks using a time-stratified approach and conditional logistic regression. Among 632 subjects with gout, there was a significant dose-response relationship between mean temperature in the prior 48 hours and the risk of subsequent gout attack (P = 0.01 for linear trend). Higher temperatures were associated with approximately 40% higher risk of gout attack compared with moderate temperatures. There was a reverse J-shaped relationship between mean relative humidity and the risk of gout attacks (P = 0.03 for quadratic trend). The combination of high temperature and low humidity had the greatest association (odds ratio = 2.04, 95% confidence interval: 1.26, 3.30) compared with moderate temperature and relative humidity. Thus, high ambient temperature and possibly extremes of humidity were associated with an increased risk of gout attack, despite the likelihood that individuals are often in climate-controlled indoor environments. PMID:24993733

Defense of Cyber Infrastructures Against Cyber-Physical Attacks Using Game-Theoretic Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, Nageswara S. V.; Poole, Stephen W.; Ma, Chris Y. T.

The operation of cyber infrastructures relies on both cyber and physical components, which are subject to incidental and intentional degradations of different kinds. Within the context of network and computing infrastructures, we study the strategic interactions between an attacker and a defender using game-theoretic models that take into account both cyber and physical components. The attacker and defender optimize their individual utilities expressed as sums of cost and system terms. First, we consider a Boolean attack-defense model, wherein the cyber and physical sub-infrastructures may be attacked and reinforced as individual units. Second, we consider a component attack-defense model wherein theirmore » components may be attacked and defended, and the infrastructure requires minimum numbers of both to function. We show that the Nash equilibrium under uniform costs in both cases is computable in polynomial time, and it provides high-level deterministic conditions for the infrastructure survival. When probabilities of successful attack and defense, and of incidental failures are incorporated into the models, the results favor the attacker but otherwise remain qualitatively similar. This approach has been motivated and validated by our experiences with UltraScience Net infrastructure, which was built to support high-performance network experiments. In conclusion, the analytical results, however, are more general, and we apply them to simplified models of cloud and high-performance computing infrastructures.« less

The influence of weather on migraine – are migraine attacks predictable?

PubMed Central

Hoffmann, Jan; Schirra, Tonio; Lo, Hendra; Neeb, Lars; Reuter, Uwe; Martus, Peter

2015-01-01

Objective The study aimed at elucidating a potential correlation between specific meteorological variables and the prevalence and intensity of migraine attacks as well as exploring a potential individual predictability of a migraine attack based on meteorological variables and their changes. Methods Attack prevalence and intensity of 100 migraineurs were correlated with atmospheric pressure, relative air humidity, and ambient temperature in 4-h intervals over 12 consecutive months. For each correlation, meteorological parameters at the time of the migraine attack as well as their variation within the preceding 24 h were analyzed. For migraineurs showing a positive correlation, logistic regression analysis was used to assess the predictability of a migraine attack based on meteorological information. Results In a subgroup of migraineurs, a significant weather sensitivity could be observed. In contrast, pooled analysis of all patients did not reveal a significant association. An individual prediction of a migraine attack based on meteorological data was not possible, mainly as a result of the small prevalence of attacks. Interpretation The results suggest that only a subgroup of migraineurs is sensitive to specific weather conditions. Our findings may provide an explanation as to why previous studies, which commonly rely on a pooled analysis, show inconclusive results. The lack of individual attack predictability indicates that the use of preventive measures based on meteorological conditions is not feasible. PMID:25642431

High angle of attack flying qualities criteria for longitudinal rate command systems

NASA Technical Reports Server (NTRS)

Wilson, David J.; Citurs, Kevin D.; Davidson, John B.

1994-01-01

This study was designed to investigate flying qualities requirements of alternate pitch command systems for fighter aircraft at high angle of attack. Flying qualities design guidelines have already been developed for angle of attack command systems at 30, 45, and 60 degrees angle of attack, so this research fills a similar need for rate command systems. Flying qualities tasks that require post-stall maneuvering were tested during piloted simulations in the McDonnell Douglas Aerospace Manned Air Combat Simulation facility. A generic fighter aircraft model was used to test angle of attack rate and pitch rate command systems for longitudinal gross acquisition and tracking tasks at high angle of attack. A wide range of longitudinal dynamic variations were tested at 30, 45, and 60 degrees angle of attack. Pilot comments, Cooper-Harper ratings, and pilot induced oscillation ratings were taken from five pilots from NASA, USN, CAF, and McDonnell Douglas Aerospace. This data was used to form longitudinal design guidelines for rate command systems at high angle of attack. These criteria provide control law design guidance for fighter aircraft at high angle of attack, low speed flight conditions. Additional time history analyses were conducted using the longitudinal gross acquisition data to look at potential agility measures of merit and correlate agility usage to flying qualities boundaries. This paper presents an overview of this research.

Defender-Attacker Decision Tree Analysis to Combat Terrorism.

PubMed

Garcia, Ryan J B; von Winterfeldt, Detlof

2016-12-01

We propose a methodology, called defender-attacker decision tree analysis, to evaluate defensive actions against terrorist attacks in a dynamic and hostile environment. Like most game-theoretic formulations of this problem, we assume that the defenders act rationally by maximizing their expected utility or minimizing their expected costs. However, we do not assume that attackers maximize their expected utilities. Instead, we encode the defender's limited knowledge about the attacker's motivations and capabilities as a conditional probability distribution over the attacker's decisions. We apply this methodology to the problem of defending against possible terrorist attacks on commercial airplanes, using one of three weapons: infrared-guided MANPADS (man-portable air defense systems), laser-guided MANPADS, or visually targeted RPGs (rocket propelled grenades). We also evaluate three countermeasures against these weapons: DIRCMs (directional infrared countermeasures), perimeter control around the airport, and hardening airplanes. The model includes deterrence effects, the effectiveness of the countermeasures, and the substitution of weapons and targets once a specific countermeasure is selected. It also includes a second stage of defensive decisions after an attack occurs. Key findings are: (1) due to the high cost of the countermeasures, not implementing countermeasures is the preferred defensive alternative for a large range of parameters; (2) if the probability of an attack and the associated consequences are large, a combination of DIRCMs and ground perimeter control are preferred over any single countermeasure. © 2016 Society for Risk Analysis.

Defense of Cyber Infrastructures Against Cyber-Physical Attacks Using Game-Theoretic Models.

PubMed

Rao, Nageswara S V; Poole, Stephen W; Ma, Chris Y T; He, Fei; Zhuang, Jun; Yau, David K Y

2016-04-01

The operation of cyber infrastructures relies on both cyber and physical components, which are subject to incidental and intentional degradations of different kinds. Within the context of network and computing infrastructures, we study the strategic interactions between an attacker and a defender using game-theoretic models that take into account both cyber and physical components. The attacker and defender optimize their individual utilities, expressed as sums of cost and system terms. First, we consider a Boolean attack-defense model, wherein the cyber and physical subinfrastructures may be attacked and reinforced as individual units. Second, we consider a component attack-defense model wherein their components may be attacked and defended, and the infrastructure requires minimum numbers of both to function. We show that the Nash equilibrium under uniform costs in both cases is computable in polynomial time, and it provides high-level deterministic conditions for the infrastructure survival. When probabilities of successful attack and defense, and of incidental failures, are incorporated into the models, the results favor the attacker but otherwise remain qualitatively similar. This approach has been motivated and validated by our experiences with UltraScience Net infrastructure, which was built to support high-performance network experiments. The analytical results, however, are more general, and we apply them to simplified models of cloud and high-performance computing infrastructures. © 2015 Society for Risk Analysis.

Heart attack first aid

MedlinePlus

First aid - heart attack; First aid - cardiopulmonary arrest; First aid - cardiac arrest ... A heart attack occurs when the blood flow that carries oxygen to the heart is blocked. The heart muscle ...

Correlated Attack Modeling (CAM)

DTIC Science & Technology

2003-10-01

describing attack models to a scenario recognition engine, a prototype of such an engine was developed, using components of the EMERALD intrusion...content. Results – The attacker gains information enabling remote access to database (i.e., privileged login information, database layout to allow...engine that uses attack specifications written in CAML. The implementation integrates two advanced technologies devel- oped in the EMERALD program [27, 31

Daily Stress as a Trigger of Migraine Attacks: Results of Thirteen Single-Subject Studies.

ERIC Educational Resources Information Center

Kohler, Thomas; Haimerl, Christianne

1990-01-01

Six-month longitudinal study examined whether migraine attacks were preceded by or occurred on stressful days. Every evening, 13 patients completed questionnaires assessing daily stress. Analyses on single-subject level tested when attacks occurred. Increased stress was generally not found for Days 2 and 3 before an attack, but often for Day 1 and…

Pre-Attack Symptomatology and Temperament as Predictors of Children's Responses to the September 11 Terrorist Attacks

ERIC Educational Resources Information Center

Lengua, Liliana J.; Long, Anna C.; Smith, Kimberlee I.; Meltzoff, Andrew N.

2005-01-01

Background: The aims of this study were to assess the psychological response of children following the September 11, 2001 terrorist attacks in New York and Washington, DC and to examine prospective predictors of children's post-attack responses. Method: Children's responses were assessed in a community sample of children in Seattle, Washington,…

Mountain pine beetle attack in ponderosa pine: Comparing methods for rating susceptibility

Treesearch

David C. Chojnacky; Barbara J. Bentz; Jesse A. Logan

2000-01-01

Two empirical methods for rating susceptibility of mountain pine beetle attack in ponderosa pine were evaluated. The methods were compared to stand data modeled to objectively rate each sampled stand for susceptibly to bark-beetle attack. Data on bark-beetle attacks, from a survey of 45 sites throughout the Colorado Plateau, were modeled using logistic regression to...

The robustness of multiplex networks under layer node-based attack

PubMed Central

Zhao, Da-wei; Wang, Lian-hai; Zhi, Yong-feng; Zhang, Jun; Wang, Zhen

2016-01-01

From transportation networks to complex infrastructures, and to social and economic networks, a large variety of systems can be described in terms of multiplex networks formed by a set of nodes interacting through different network layers. Network robustness, as one of the most successful application areas of complex networks, has attracted great interest in a myriad of research realms. In this regard, how multiplex networks respond to potential attack is still an open issue. Here we study the robustness of multiplex networks under layer node-based random or targeted attack, which means that nodes just suffer attacks in a given layer yet no additional influence to their connections beyond this layer. A theoretical analysis framework is proposed to calculate the critical threshold and the size of giant component of multiplex networks when nodes are removed randomly or intentionally. Via numerous simulations, it is unveiled that the theoretical method can accurately predict the threshold and the size of giant component, irrespective of attack strategies. Moreover, we also compare the robustness of multiplex networks under multiplex node-based attack and layer node-based attack, and find that layer node-based attack makes multiplex networks more vulnerable, regardless of average degree and underlying topology. PMID:27075870

The robustness of multiplex networks under layer node-based attack.

PubMed

Zhao, Da-wei; Wang, Lian-hai; Zhi, Yong-feng; Zhang, Jun; Wang, Zhen

2016-04-14

From transportation networks to complex infrastructures, and to social and economic networks, a large variety of systems can be described in terms of multiplex networks formed by a set of nodes interacting through different network layers. Network robustness, as one of the most successful application areas of complex networks, has attracted great interest in a myriad of research realms. In this regard, how multiplex networks respond to potential attack is still an open issue. Here we study the robustness of multiplex networks under layer node-based random or targeted attack, which means that nodes just suffer attacks in a given layer yet no additional influence to their connections beyond this layer. A theoretical analysis framework is proposed to calculate the critical threshold and the size of giant component of multiplex networks when nodes are removed randomly or intentionally. Via numerous simulations, it is unveiled that the theoretical method can accurately predict the threshold and the size of giant component, irrespective of attack strategies. Moreover, we also compare the robustness of multiplex networks under multiplex node-based attack and layer node-based attack, and find that layer node-based attack makes multiplex networks more vulnerable, regardless of average degree and underlying topology.

Cyber-Physical Attack-Resilient Wide-Area Monitoring, Protection, and Control for the Power Grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashok, Aditya; Govindarasu, Manimaran; Wang, Jianhui

Cyber security and resiliency of Wide-Area Monitoring, Protection and Control (WAMPAC) applications is critically important to ensure secure, reliable, and economic operation of the bulk power system. WAMPAC relies heavily on the security of measurements and control commands transmitted over wide-area communication networks for real-time operational, protection, and control functions. Also, the current “N-1 security criteria” for grid operation is inadequate to address malicious cyber events and therefore it is important to fundamentally redesign WAMPAC and to enhance Energy Management System (EMS) applications to make them attack-resilient. In this paper, we propose an end-to-end defense-in-depth architecture for attack-resilient WAMPAC thatmore » addresses resilience at both the infrastructure layer and the application layers. Also, we propose an attack-resilient cyber-physical security framework that encompasses the entire security life cycle including risk assessment, attack prevention, attack detection, attack mitigation, and attack resilience. The overarching objective of this paper is to provide a broad scope that comprehensively describes most of the major research issues and potential solutions in the context of cyber-physical security of WAMPAC for the power grid.« less

Accurate Sybil Attack Detection Based on Fine-Grained Physical Channel Information.

PubMed

Wang, Chundong; Zhu, Likun; Gong, Liangyi; Zhao, Zhentang; Yang, Lei; Liu, Zheli; Cheng, Xiaochun

2018-03-15

With the development of the Internet-of-Things (IoT), wireless network security has more and more attention paid to it. The Sybil attack is one of the famous wireless attacks that can forge wireless devices to steal information from clients. These forged devices may constantly attack target access points to crush the wireless network. In this paper, we propose a novel Sybil attack detection based on Channel State Information (CSI). This detection algorithm can tell whether the static devices are Sybil attackers by combining a self-adaptive multiple signal classification algorithm with the Received Signal Strength Indicator (RSSI). Moreover, we develop a novel tracing scheme to cluster the channel characteristics of mobile devices and detect dynamic attackers that change their channel characteristics in an error area. Finally, we experiment on mobile and commercial WiFi devices. Our algorithm can effectively distinguish the Sybil devices. The experimental results show that our Sybil attack detection system achieves high accuracy for both static and dynamic scenarios. Therefore, combining the phase and similarity of channel features, the multi-dimensional analysis of CSI can effectively detect Sybil nodes and improve the security of wireless networks.

Accurate Sybil Attack Detection Based on Fine-Grained Physical Channel Information

PubMed Central

Wang, Chundong; Zhao, Zhentang; Yang, Lei; Liu, Zheli; Cheng, Xiaochun

2018-01-01

With the development of the Internet-of-Things (IoT), wireless network security has more and more attention paid to it. The Sybil attack is one of the famous wireless attacks that can forge wireless devices to steal information from clients. These forged devices may constantly attack target access points to crush the wireless network. In this paper, we propose a novel Sybil attack detection based on Channel State Information (CSI). This detection algorithm can tell whether the static devices are Sybil attackers by combining a self-adaptive multiple signal classification algorithm with the Received Signal Strength Indicator (RSSI). Moreover, we develop a novel tracing scheme to cluster the channel characteristics of mobile devices and detect dynamic attackers that change their channel characteristics in an error area. Finally, we experiment on mobile and commercial WiFi devices. Our algorithm can effectively distinguish the Sybil devices. The experimental results show that our Sybil attack detection system achieves high accuracy for both static and dynamic scenarios. Therefore, combining the phase and similarity of channel features, the multi-dimensional analysis of CSI can effectively detect Sybil nodes and improve the security of wireless networks. PMID:29543773