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Sample records for replicates supported nematode

  1. Nematodes

    International Nuclear Information System (INIS)

    Suzuki, Kenshi; Ishii, Naoaki

    1977-01-01

    Utilization of nematodes for a study of radiation biology was considered. Structure, generation, rearing method, and genetic nature of nematodes (Caenorhabditis elegans, Turbatri acetic, etc.) were given an outline. As the advantage of a study using nematodes as materials, shortness of one generation time, simplicity in structure, and smallness of the whole cells, specific regular movement, and heliotaxis to chemical substances and light were mentioned. Effect of x-ray on survival rate of nematodes and effect of ultraviolet on nematodes and their eggs were described. It was suggested that nematodes was useful for studies on aging and radiation biology, and a possibility existed that nematodes would be used in studies of cancer and malformation. (Serizawa, K.)

  2. Natural variation in dauer pheromone production and sensing supports intraspecific competition in nematodes.

    Science.gov (United States)

    Bose, Neelanjan; Meyer, Jan M; Yim, Joshua J; Mayer, Melanie G; Markov, Gabriel V; Ogawa, Akira; Schroeder, Frank C; Sommer, Ralf J

    2014-07-07

    Dauer formation, a major nematode survival strategy, represents a model for small-molecule regulation of metazoan development [1-10]. Free-living nematodes excrete dauer-inducing pheromones that have been assumed to target conspecifics of the same genotype [9, 11]. However, recent studies in Pristionchus pacificus revealed that the dauer pheromone of some strains affects conspecifics of other genotypes more strongly than individuals of the same genotype [12]. To elucidate the mechanistic basis for this intriguing cross-preference, we compared six P. pacificus wild isolates to determine the chemical composition of their dauer-inducing metabolomes and responses to individual pheromone components. We found that these isolates produce dauer pheromone blends of different composition and respond differently to individual pheromone components. Strikingly, there is no correlation between production of and dauer response to a specific compound in individual strains. Specifically, pheromone components that are abundantly produced by one genotype induce dauer formation in other genotypes, but not necessarily in the abundant producer. Furthermore, some genotypes respond to pheromone components they do not produce themselves. These results support a model of intraspecific competition in nematode dauer formation. Indeed, we observed intraspecific competition among sympatric strains in a novel experimental assay, suggesting a new role of small molecules in nematode ecology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. ATM supports gammaherpesvirus replication by attenuating type I interferon pathway.

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    Darrah, Eric J; Stoltz, Kyle P; Ledwith, Mitchell; Tarakanova, Vera L

    2017-10-01

    Ataxia-Telangiectasia mutated (ATM) kinase participates in multiple networks, including DNA damage response, oxidative stress, and mitophagy. ATM also supports replication of diverse DNA and RNA viruses. Gammaherpesviruses are prevalent cancer-associated viruses that benefit from ATM expression during replication. This proviral role of ATM had been ascribed to its signaling within the DNA damage response network; other functions of ATM have not been considered. In this study increased type I interferon (IFN) responses were observed in ATM deficient gammaherpesvirus-infected macrophages. Using a mouse model that combines ATM and type I IFN receptor deficiencies we show that increased type I IFN response in the absence of ATM fully accounts for the proviral role of ATM during gammaherpesvirus replication. Further, increased type I IFN response rendered ATM deficient macrophages more susceptible to antiviral effects of type II IFN. This study identifies attenuation of type I IFN responses as the primary mechanism underlying proviral function of ATM during gammaherpesvirus infection. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Prereplicative complexes assembled in vitro support origin-dependent and independent DNA replication

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    On, Kin Fan; Beuron, Fabienne; Frith, David; Snijders, Ambrosius P; Morris, Edward P; Diffley, John F X

    2014-01-01

    Eukaryotic DNA replication initiates from multiple replication origins. To ensure each origin fires just once per cell cycle, initiation is divided into two biochemically discrete steps: the Mcm2-7 helicase is first loaded into prereplicative complexes (pre-RCs) as an inactive double hexamer by the origin recognition complex (ORC), Cdt1 and Cdc6; the helicase is then activated by a set of “firing factors.” Here, we show that plasmids containing pre-RCs assembled with purified proteins support complete and semi-conservative replication in extracts from budding yeast cells overexpressing firing factors. Replication requires cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK). DDK phosphorylation of Mcm2-7 does not by itself promote separation of the double hexamer, but is required for the recruitment of firing factors and replisome components in the extract. Plasmid replication does not require a functional replication origin; however, in the presence of competitor DNA and limiting ORC concentrations, replication becomes origin-dependent in this system. These experiments indicate that Mcm2-7 double hexamers can be precursors of replication and provide insight into the nature of eukaryotic DNA replication origins. PMID:24566989

  5. Adenovirus E1A/E1B Transformed Amniotic Fluid Cells Support Human Cytomegalovirus Replication

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    Natascha Krömmelbein

    2016-02-01

    Full Text Available The human cytomegalovirus (HCMV replicates to high titers in primary human fibroblast cell cultures. A variety of primary human cells and some tumor-derived cell lines do also support permissive HCMV replication, yet at low levels. Cell lines established by transfection of the transforming functions of adenoviruses have been notoriously resistant to HCMV replication and progeny production. Here, we provide first-time evidence that a permanent cell line immortalized by adenovirus type 5 E1A and E1B (CAP is supporting the full HCMV replication cycle and is releasing infectious progeny. The CAP cell line had previously been established from amniotic fluid cells which were likely derived from membranes of the developing fetus. These cells can be grown under serum-free conditions. HCMV efficiently penetrated CAP cells, expressed its immediate-early proteins and dispersed restrictive PML-bodies. Viral DNA replication was initiated and viral progeny became detectable by electron microscopy in CAP cells. Furthermore, infectious virus was released from CAP cells, yet to lower levels compared to fibroblasts. Subviral dense bodies were also secreted from CAP cells. The results show that E1A/E1B expression in transformed cells is not generally repressive to HCMV replication and that CAP cells may be a good substrate for dense body based vaccine production.

  6. Support, shape and number of replicate samples for tree foliage analysis.

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    Luyssaert, Sebastiaan; Mertens, Jan; Raitio, Hannu

    2003-06-01

    Many fundamental features of a sampling program are determined by the heterogeneity of the object under study and the settings for the error (alpha), the power (beta), the effect size (ES), the number of replicate samples, and sample support, which is a feature that is often overlooked. The number of replicates, alpha, beta, ES, and sample support are interconnected. The effect of the sample support and its shape on the required number of replicate samples was investigated by means of a resampling method. The method was applied to a simulated distribution of Cd in the crown of a Salix fragilis L. tree. Increasing the dimensions of the sample support results in a decrease in the variance of the element concentration under study. Analysis of the variance is often the foundation of statistical tests, therefore, valid statistical testing requires the use of a fixed sample support during the experiment. This requirement might be difficult to meet in time-series analyses and long-term monitoring programs. Sample supports have their largest dimension in the direction with the largest heterogeneity, i.e. the direction representing the crown height, and this will give more accurate results than supports with other shapes. Taking the relationships between the sample support and the variance of the element concentrations in tree crowns into account provides guidelines for sampling efficiency in terms of precision and costs. In terms of time, the optimal support to test whether the average Cd concentration of the crown exceeds a threshold value is 0.405 m3 (alpha = 0.05, beta = 0.20, ES = 1.0 mg kg(-1) dry mass). The average weight of this support is 23 g dry mass, and 11 replicate samples need to be taken. It should be noted that in this case the optimal support applies to Cd under conditions similar to those of the simulation, but not necessarily all the examinations for this tree species, element, and hypothesis test.

  7. Hematopoietic Cancer Cell Lines Can Support Replication of Sabin Poliovirus Type 1

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    van Eikenhorst, Gerco; de Gruijl, Tanja D.; van der Pol, Leo A.; Bakker, Wilfried A. M.

    2015-01-01

    Viral vaccines can be produced in adherent or in suspension cells. The objective of this work was to screen human suspension cell lines for the capacity to support viral replication. As the first step, it was investigated whether poliovirus can replicate in such cell lines. Sabin poliovirus type 1 was serially passaged on five human cell lines, HL60, K562, KG1, THP-1, and U937. Sabin type 1 was capable of efficiently replicating in three cell lines (K562, KG1, and U937), yielding high viral titers after replication. Expression of CD155, the poliovirus receptor, did not explain susceptibility to replication, since all cell lines expressed CD155. Furthermore, we showed that passaged virus replicated more efficiently than parental virus in KG1 cells, yielding higher virus titers in the supernatant early after infection. Infection of cell lines at an MOI of 0.01 resulted in high viral titers in the supernatant at day 4. Infection of K562 with passaged Sabin type 1 in a bioreactor system yielded high viral titers in the supernatant. Altogether, these data suggest that K562, KG1, and U937 cell lines are useful for propagation of poliovirus. PMID:25815312

  8. Brief Report: An Independent Replication and Extension of Psychometric Evidence Supporting the Theory of Mind Inventory

    Science.gov (United States)

    Greenslade, Kathryn J.; Coggins, Truman E.

    2016-01-01

    This study presents an independent replication and extension of psychometric evidence supporting the "Theory of Mind Inventory" ("ToMI"). Parents of 20 children with ASD (4; 1-6; 7 years; months) and 20 with typical development (3; 1-6; 5), rated their child's theory of mind abilities in everyday situations. Other parent report…

  9. Support, shape and number of replicate samples for tree foliage analysis

    NARCIS (Netherlands)

    Luyssaert, Sebastiaan; Mertens, Jan; Raitio, Hannu

    Many fundamental features of a sampling program are determined by the heterogeneity of the object under study and the settings for the error (α), the power (β), the effect size (ES), the number of replicate samples, and sample support, which is a feature that is often overlooked. The number of

  10. SARS-coronavirus replication is supported by a reticulovesicular network of modified endoplasmic reticulum.

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    Kèvin Knoops

    2008-09-01

    Full Text Available Positive-strand RNA viruses, a large group including human pathogens such as SARS-coronavirus (SARS-CoV, replicate in the cytoplasm of infected host cells. Their replication complexes are commonly associated with modified host cell membranes. Membrane structures supporting viral RNA synthesis range from distinct spherular membrane invaginations to more elaborate webs of packed membranes and vesicles. Generally, their ultrastructure, morphogenesis, and exact role in viral replication remain to be defined. Poorly characterized double-membrane vesicles (DMVs were previously implicated in SARS-CoV RNA synthesis. We have now applied electron tomography of cryofixed infected cells for the three-dimensional imaging of coronavirus-induced membrane alterations at high resolution. Our analysis defines a unique reticulovesicular network of modified endoplasmic reticulum that integrates convoluted membranes, numerous interconnected DMVs (diameter 200-300 nm, and "vesicle packets" apparently arising from DMV merger. The convoluted membranes were most abundantly immunolabeled for viral replicase subunits. However, double-stranded RNA, presumably revealing the site of viral RNA synthesis, mainly localized to the DMV interior. Since we could not discern a connection between DMV interior and cytosol, our analysis raises several questions about the mechanism of DMV formation and the actual site of SARS-CoV RNA synthesis. Our data document the extensive virus-induced reorganization of host cell membranes into a network that is used to organize viral replication and possibly hide replicating RNA from antiviral defense mechanisms. Together with biochemical studies of the viral enzyme complex, our ultrastructural description of this "replication network" will aid to further dissect the early stages of the coronavirus life cycle and its virus-host interactions.

  11. The evolutionary position of nematodes

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    Gojobori Takashi

    2002-04-01

    Full Text Available Abstract Background The complete genomes of three animals have been sequenced by global research efforts: a nematode worm (Caenorhabditis elegans, an insect (Drosophila melanogaster, and a vertebrate (Homo sapiens. Remarkably, their relationships have yet to be clarified. The confusion concerns the enigmatic position of nematodes. Traditionally, nematodes have occupied a basal position, in part because they lack a true body cavity. However, the leading hypothesis now joins nematodes with arthropods in a molting clade, Ecdysozoa, based on data from several genes. Results We tested the Ecdysozoa hypothesis with analyses of more than 100 nuclear protein alignments, under conditions that would expose biases, and found that it was not supported. Instead, we found significant support for the traditional hypothesis, Coelomata. Our result is robust to different rates of sequence change among genes and lineages, different numbers of taxa, and different species of nematodes. Conclusion We conclude that insects (arthropods are genetically and evolutionarily closer to humans than to nematode worms.

  12. Applying a multi-replication framework to support dynamic situation assessment and predictive capabilities

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    Lammers, Craig; McGraw, Robert M.; Steinman, Jeffrey S.

    2005-05-01

    Technological advances and emerging threats reduce the time between target detection and action to an order of a few minutes. To effectively assist with the decision-making process, C4I decision support tools must quickly and dynamically predict and assess alternative Courses Of Action (COAs) to assist Commanders in anticipating potential outcomes. These capabilities can be provided through the faster-than-real-time predictive simulation of plans that are continuously re-calibrating with the real-time picture. This capability allows decision-makers to assess the effects of re-tasking opportunities, providing the decision-maker with tremendous freedom to make time-critical, mid-course decisions. This paper presents an overview and demonstrates the use of a software infrastructure that supports DSAP capabilities. These DSAP capabilities are demonstrated through the use of a Multi-Replication Framework that supports (1) predictivie simulations using JSAF (Joint Semi-Automated Forces); (2) real-time simulation, also using JSAF, as a state estimation mechanism; and, (3) real-time C4I data updates through TBMCS (Theater Battle Management Core Systems). This infrastructure allows multiple replications of a simulation to be executed simultaneously over a grid faster-than-real-time, calibrated with live data feeds. A cost evaluator mechanism analyzes potential outcomes and prunes simulations that diverge from the real-time picture. In particular, this paper primarily serves to walk a user through the process for using the Multi-Replication Framework providing an enhanced decision aid.

  13. Oral keratinocytes support non-replicative infection and transfer of harbored HIV-1 to permissive cells.

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    Vacharaksa, Anjalee; Asrani, Anil C; Gebhard, Kristin H; Fasching, Claudine E; Giacaman, Rodrigo A; Janoff, Edward N; Ross, Karen F; Herzberg, Mark C

    2008-07-17

    Oral keratinocytes on the mucosal surface are frequently exposed to HIV-1 through contact with infected sexual partners or nursing mothers. To determine the plausibility that oral keratinocytes are primary targets of HIV-1, we tested the hypothesis that HIV-1 infects oral keratinocytes in a restricted manner. To study the fate of HIV-1, immortalized oral keratinocytes (OKF6/TERT-2; TERT-2 cells) were characterized for the fate of HIV-specific RNA and DNA. At 6 h post inoculation with X4 or R5-tropic HIV-1, HIV-1gag RNA was detected maximally within TERT-2 cells. Reverse transcriptase activity in TERT-2 cells was confirmed by VSV-G-mediated infection with HIV-NL4-3Deltaenv-EGFP. AZT inhibited EGFP expression in a dose-dependent manner, suggesting that viral replication can be supported if receptors are bypassed. Within 3 h post inoculation, integrated HIV-1 DNA was detected in TERT-2 cell nuclei and persisted after subculture. Multiply spliced and unspliced HIV-1 mRNAs were not detectable up to 72 h post inoculation, suggesting that HIV replication may abort and that infection is non-productive. Within 48 h post inoculation, however, virus harbored by CD4 negative TERT-2 cells trans infected co-cultured peripheral blood mononuclear cells (PBMCs) or MOLT4 cells (CD4+ CCR5+) by direct cell-to-cell transfer or by releasing low levels of infectious virions. Primary tonsil epithelial cells also trans infected HIV-1 to permissive cells in a donor-specific manner. Oral keratinocytes appear, therefore, to support stable non-replicative integration, while harboring and transmitting infectious X4- or R5-tropic HIV-1 to permissive cells for up to 48 h.

  14. Oral keratinocytes support non-replicative infection and transfer of harbored HIV-1 to permissive cells

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    Giacaman Rodrigo A

    2008-07-01

    Full Text Available Abstract Background Oral keratinocytes on the mucosal surface are frequently exposed to HIV-1 through contact with infected sexual partners or nursing mothers. To determine the plausibility that oral keratinocytes are primary targets of HIV-1, we tested the hypothesis that HIV-1 infects oral keratinocytes in a restricted manner. Results To study the fate of HIV-1, immortalized oral keratinocytes (OKF6/TERT-2; TERT-2 cells were characterized for the fate of HIV-specific RNA and DNA. At 6 h post inoculation with X4 or R5-tropic HIV-1, HIV-1gag RNA was detected maximally within TERT-2 cells. Reverse transcriptase activity in TERT-2 cells was confirmed by VSV-G-mediated infection with HIV-NL4-3Δenv-EGFP. AZT inhibited EGFP expression in a dose-dependent manner, suggesting that viral replication can be supported if receptors are bypassed. Within 3 h post inoculation, integrated HIV-1 DNA was detected in TERT-2 cell nuclei and persisted after subculture. Multiply spliced and unspliced HIV-1 mRNAs were not detectable up to 72 h post inoculation, suggesting that HIV replication may abort and that infection is non-productive. Within 48 h post inoculation, however, virus harbored by CD4 negative TERT-2 cells trans infected co-cultured peripheral blood mononuclear cells (PBMCs or MOLT4 cells (CD4+ CCR5+ by direct cell-to-cell transfer or by releasing low levels of infectious virions. Primary tonsil epithelial cells also trans infected HIV-1 to permissive cells in a donor-specific manner. Conclusion Oral keratinocytes appear, therefore, to support stable non-replicative integration, while harboring and transmitting infectious X4- or R5-tropic HIV-1 to permissive cells for up to 48 h.

  15. Brief Report: An Independent Replication and Extension of Psychometric Evidence Supporting the Theory of Mind Inventory.

    Science.gov (United States)

    Greenslade, Kathryn J; Coggins, Truman E

    2016-08-01

    This study presents an independent replication and extension of psychometric evidence supporting the Theory of Mind Inventory (ToMI). Parents of 20 children with ASD (4; 1-6; 7 years; months) and 20 with typical development (3; 1-6; 5), rated their child's theory of mind abilities in everyday situations. Other parent report and child behavioral assessments included the Social Responsiveness Scale-2, Vineland Adaptive Behavior Scales-2, Peabody Picture Vocabulary Test-4, and Clinical Evaluation of Language Fundamentals-Preschool, 2. Results revealed high internal consistency, expected developmental changes in children with typical development, expected group differences between children with and without ASD, and strong correlations with other measures of social and communication abilities. The ToMI demonstrates strong psychometrics, suggesting considerable utility in identifying theory of mind deficits in children with ASD.

  16. Eosinophils and IL-4 Support Nematode Growth Coincident with an Innate Response to Tissue Injury.

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    Huang, Lu; Beiting, Daniel P; Gebreselassie, Nebiat G; Gagliardo, Lucille F; Ruyechan, Maura C; Lee, Nancy A; Lee, James J; Appleton, Judith A

    2015-12-01

    It has become increasingly clear that the functions of eosinophils extend beyond host defense and allergy to metabolism and tissue regeneration. These influences have strong potential to be relevant in worm infections in which eosinophils are prominent and parasites rely on the host for nutrients to support growth or reproduction. The aim of this study was to investigate the mechanism underlying the observation that eosinophils promote growth of Trichinella spiralis larvae in skeletal muscle. Our results indicate that IL-4 and eosinophils are necessary for normal larval growth and that eosinophils from IL-4 competent mice are sufficient to support growth. The eosinophil-mediated effect operates in the absence of adaptive immunity. Following invasion by newborn larvae, host gene expression in skeletal muscle was compatible with a regenerative response and a shift in the source of energy in infected tissue. The presence of eosinophils suppressed local inflammation while also influencing nutrient homeostasis in muscle. Redistribution of glucose transporter 4 (GLUT4) and phosphorylation of Akt were observed in nurse cells, consistent with enhancement of glucose uptake and glycogen storage by larvae that is known to occur. The data are consistent with a mechanism in which eosinophils promote larval growth by an IL-4 dependent mechanism that limits local interferon-driven responses that otherwise alter nutrient metabolism in infected muscle. Our findings document a novel interaction between parasite and host in which worms have evolved a strategy to co-opt an innate host cell response in a way that facilitates their growth.

  17. Eosinophils and IL-4 Support Nematode Growth Coincident with an Innate Response to Tissue Injury.

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    Lu Huang

    2015-12-01

    Full Text Available It has become increasingly clear that the functions of eosinophils extend beyond host defense and allergy to metabolism and tissue regeneration. These influences have strong potential to be relevant in worm infections in which eosinophils are prominent and parasites rely on the host for nutrients to support growth or reproduction. The aim of this study was to investigate the mechanism underlying the observation that eosinophils promote growth of Trichinella spiralis larvae in skeletal muscle. Our results indicate that IL-4 and eosinophils are necessary for normal larval growth and that eosinophils from IL-4 competent mice are sufficient to support growth. The eosinophil-mediated effect operates in the absence of adaptive immunity. Following invasion by newborn larvae, host gene expression in skeletal muscle was compatible with a regenerative response and a shift in the source of energy in infected tissue. The presence of eosinophils suppressed local inflammation while also influencing nutrient homeostasis in muscle. Redistribution of glucose transporter 4 (GLUT4 and phosphorylation of Akt were observed in nurse cells, consistent with enhancement of glucose uptake and glycogen storage by larvae that is known to occur. The data are consistent with a mechanism in which eosinophils promote larval growth by an IL-4 dependent mechanism that limits local interferon-driven responses that otherwise alter nutrient metabolism in infected muscle. Our findings document a novel interaction between parasite and host in which worms have evolved a strategy to co-opt an innate host cell response in a way that facilitates their growth.

  18. RNAi effector diversity in nematodes.

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    Johnathan J Dalzell

    2011-06-01

    Full Text Available While RNA interference (RNAi has been deployed to facilitate gene function studies in diverse helminths, parasitic nematodes appear variably susceptible. To test if this is due to inter-species differences in RNAi effector complements, we performed a primary sequence similarity survey for orthologs of 77 Caenorhabditis elegans RNAi pathway proteins in 13 nematode species for which genomic or transcriptomic datasets were available, with all outputs subjected to domain-structure verification. Our dataset spanned transcriptomes of Ancylostoma caninum and Oesophagostomum dentatum, and genomes of Trichinella spiralis, Ascaris suum, Brugia malayi, Haemonchus contortus, Meloidogyne hapla, Meloidogyne incognita and Pristionchus pacificus, as well as the Caenorhabditis species C. brenneri, C. briggsae, C. japonica and C. remanei, and revealed that: (i Most of the C. elegans proteins responsible for uptake and spread of exogenously applied double stranded (dsRNA are absent from parasitic species, including RNAi-competent plant-nematodes; (ii The Argonautes (AGOs responsible for gene expression regulation in C. elegans are broadly conserved, unlike those recruited during the induction of RNAi by exogenous dsRNA; (iii Secondary Argonautes (SAGOs are poorly conserved, and the nuclear AGO NRDE-3 was not identified in any parasite; (iv All five Caenorhabditis spp. possess an expanded RNAi effector repertoire relative to the parasitic nematodes, consistent with the propensity for gene loss in nematode parasites; (v In spite of the quantitative differences in RNAi effector complements across nematode species, all displayed qualitatively similar coverage of functional protein groups. In summary, we could not identify RNAi effector deficiencies that associate with reduced susceptibility in parasitic nematodes. Indeed, similarities in the RNAi effector complements of RNAi refractory and competent nematode parasites support the broad applicability of this research

  19. Gambling, Risk-Taking, and Antisocial Behavior: A Replication Study Supporting the Generality of Deviance.

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    Mishra, Sandeep; Lalumière, Martin L; Williams, Robert J

    2017-03-01

    Research suggests that high frequency gambling is a component of the "generality of deviance", which describes the observation that various forms of risky and antisocial behavior tend to co-occur among individuals. Furthermore, risky and antisocial behaviors have been associated with such personality traits as low self-control, and impulsivity, and sensation-seeking. We conducted a replication (and extension) of two previous studies examining whether high frequency gambling is part of the generality of deviance using a large and diverse community sample (n = 328). This study was conducted as a response to calls for more replication studies in the behavioral and psychological sciences (recent systematic efforts suggest that a significant proportion of psychology studies do not replicate). The results of the present study largely replicate those previously found, and in many cases, we observed stronger associations among measures of gambling, risk-taking, and antisocial behavior in this diverse sample. Together, this study provides evidence for the generality of deviance inclusive of gambling (and, some evidence for the replicability of research relating to gambling and individual differences).

  20. Adenovirus-encoding virus-associated RNAs suppress HDGF gene expression to support efficient viral replication.

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    Saki Kondo

    Full Text Available Non-coding small RNAs are involved in many physiological responses including viral life cycles. Adenovirus-encoding small RNAs, known as virus-associated RNAs (VA RNAs, are transcribed throughout the replication process in the host cells, and their transcript levels depend on the copy numbers of the viral genome. Therefore, VA RNAs are abundant in infected cells after genome replication, i.e. during the late phase of viral infection. Their function during the late phase is the inhibition of interferon-inducible protein kinase R (PKR activity to prevent antiviral responses; recently, mivaRNAs, the microRNAs processed from VA RNAs, have been reported to inhibit cellular gene expression. Although VA RNA transcription starts during the early phase, little is known about its function. The reason may be because much smaller amount of VA RNAs are transcribed during the early phase than the late phase. In this study, we applied replication-deficient adenovirus vectors (AdVs and novel AdVs lacking VA RNA genes to analyze the expression changes in cellular genes mediated by VA RNAs using microarray analysis. AdVs are suitable to examine the function of VA RNAs during the early phase, since they constitutively express VA RNAs but do not replicate except in 293 cells. We found that the expression level of hepatoma-derived growth factor (HDGF significantly decreased in response to the VA RNAs under replication-deficient condition, and this suppression was also observed during the early phase under replication-competent conditions. The suppression was independent of mivaRNA-induced downregulation, suggesting that the function of VA RNAs during the early phase differs from that during the late phase. Notably, overexpression of HDGF inhibited AdV growth. This is the first report to show the function, in part, of VA RNAs during the early phase that may be contribute to efficient viral growth.

  1. A Gossip-Based Optimistic Replication for Efficient Delay-Sensitive Streaming Using an Interactive Middleware Support System

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    Mavromoustakis, Constandinos X.; Karatza, Helen D.

    2010-06-01

    While sharing resources the efficiency is substantially degraded as a result of the scarceness of availability of the requested resources in a multiclient support manner. These resources are often aggravated by many factors like the temporal constraints for availability or node flooding by the requested replicated file chunks. Thus replicated file chunks should be efficiently disseminated in order to enable resource availability on-demand by the mobile users. This work considers a cross layered middleware support system for efficient delay-sensitive streaming by using each device's connectivity and social interactions in a cross layered manner. The collaborative streaming is achieved through the epidemically replicated file chunk policy which uses a transition-based approach of a chained model of an infectious disease with susceptible, infected, recovered and death states. The Gossip-based stateful model enforces the mobile nodes whether to host a file chunk or not or, when no longer a chunk is needed, to purge it. The proposed model is thoroughly evaluated through experimental simulation taking measures for the effective throughput Eff as a function of the packet loss parameter in contrast with the effectiveness of the replication Gossip-based policy.

  2. Adolescent Loneliness and the Interaction between the Serotonin Transporter Gene (5-HTTLPR and Parental Support: A Replication Study.

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    Annette W M Spithoven

    Full Text Available Gene-by-environment interaction (GxEs studies have gained popularity over the last decade, but the robustness of such observed interactions has been questioned. The current study contributes to this debate by replicating the only study on the interaction between the serotonin transporter gene (5-HTTLPR and perceived parental support on adolescents' peer-related loneliness. A total of 1,111 adolescents (51% boys with an average age of 13.70 years (SD = 0.93 participated and three annual waves of data were collected. At baseline, adolescent-reported parental support and peer-related loneliness were assessed and genetic information was collected. Assessment of peer-related loneliness was repeated at Waves 2 and 3. Using a cohort-sequential design, a Latent Growth Curve Model was estimated. Overall, a slight increase of loneliness over time was found. However, the development of loneliness over time was found to be different for boys and girls: girls' levels of loneliness increased over time, whereas boys' levels of loneliness decreased. Parental support was inversely related to baseline levels of loneliness, but unrelated to change of loneliness over time. We were unable to replicate the main effect of 5-HTTLPR or the 5-HTTLPR x Support interaction effect. In the Discussion, we examine the implications of our non-replication.

  3. A case with concurrent duplication, triplication, and uniparental isodisomy at 1q42.12-qter supporting microhomology-mediated break-induced replication model for replicative rearrangements.

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    Kohmoto, Tomohiro; Okamoto, Nana; Naruto, Takuya; Murata, Chie; Ouchi, Yuya; Fujita, Naoko; Inagaki, Hidehito; Satomura, Shigeko; Okamoto, Nobuhiko; Saito, Masako; Masuda, Kiyoshi; Kurahashi, Hiroki; Imoto, Issei

    2017-01-01

    Complex genomic rearrangements (CGRs) consisting of interstitial triplications in conjunction with uniparental isodisomy (isoUPD) have rarely been reported in patients with multiple congenital anomalies (MCA)/intellectual disability (ID). One-ended DNA break repair coupled with microhomology-mediated break-induced replication (MMBIR) has been recently proposed as a possible mechanism giving rise to interstitial copy number gains and distal isoUPD, although only a few cases providing supportive evidence in human congenital diseases with MCA have been documented. Here, we report on the chromosomal microarray (CMA)-based identification of the first known case with concurrent interstitial duplication at 1q42.12-q42.2 and triplication at 1q42.2-q43 followed by isoUPD for the remainder of chromosome 1q (at 1q43-qter). In distal 1q duplication/triplication overlapping with 1q42.12-q43, variable clinical features have been reported, and our 25-year-old patient with MCA/ID presented with some of these frequently described features. Further analyses including the precise mapping of breakpoint junctions within the CGR in a sequence level suggested that the CGR found in association with isoUPD in our case is a triplication with flanking duplications, characterized as a triplication with a particularly long duplication-inverted triplication-duplication (DUP-TRP/INV-DUP) structure. Because microhomology was observed in both junctions between the triplicated region and the flanking duplicated regions, our case provides supportive evidence for recently proposed replication-based mechanisms, such as MMBIR, underlying the formation of CGRs + isoUPD implicated in chromosomal disorders. To the best of our knowledge, this is the first case of CGRs + isoUPD observed in 1q and having DUP-TRP/INV-DUP structure with a long proximal duplication, which supports MMBIR-based model for genomic rearrangements. Molecular cytogenetic analyses using CMA containing single

  4. Control of Pathogenicity Root-Knot Nematode (Meloidogyne Javanica by Earthworm Eisenia Feoetida-Based Products in Greenhouse

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    M. Rostami

    2016-06-01

    Full Text Available Introduction: Biocontrol of nematode agents in order to decrease the hazardous impacts of chemical pesticide application including problems of public health and environmental pollution is apriority. In this study, solid (Vermicompost and liquid products (Liquid Vermicompost, Vermiwash and Coelomic fluidof the earthworm species Eisenia fetida were tested against root-knot nematode, Meloidogyne javanica in greenhouse conditions. Materials and Methods: In this study, Solid (Vermicompost and Liquid products(Wormtea, Vermiwash, Coelomic fluid erthworms (Eisenia foetida were tested against Meloidogyne javanica and also the effect of Vermicompost was evaluated on Pathogenicity of various nematode initial inoculum in two stage greenhouse conditions. Earthworm-based products (Vermicompost, Wormtea, Vermiwash and Coelomic fluid were added to tomato pots. Various treatments of liquid as well as solid products and their combination were used in the greenhouse trial. The first Stage greenhouse experiment- Tomato seeds grown in 2 kg sterilized soil. In the treatments having Vermicompost, pots incorporated with 200 gr of this compost homogeneously mixed with soil. After plants reached at two leaf stage, to study the effects of liquid products (Wormtea, Vermiwash, and Coelomic fluid they added to the pots (500cc along with the irrigation water every week and after of 4 leaf stage, 5000 nematode eggs and larva inoculated to the tomato host plants. 90 days after nematode inoculation, plant and nematode growth indices separately measured and compared. The experiment conducted based on completely randomized design having four replicates. The second stage greenhouse experiment- Tomato seeds grown in 2 kg sterilized soil. In the treatments, pots incorporated with 200 gr of this compost homogeneously mixed with soil. After of 4 leaf stage, 0,1000,2000,4000 and 10000 nematode eggs and larva inoculated to the tomato host plants. 90 days after nematode inoculation, plant

  5. CD200R1 supports HSV-1 viral replication and licenses pro-inflammatory signaling functions of TLR2.

    Directory of Open Access Journals (Sweden)

    Roy J Soberman

    Full Text Available The CD200R1:CD200 axis is traditionally considered to limit tissue inflammation by down-regulating pro-inflammatory signaling in myeloid cells bearing the receptor. We generated CD200R1(-/- mice and employed them to explore both the role of CD200R1 in regulating macrophage signaling via TLR2 as well as the host response to an in vivo, TLR2-dependent model, herpes simplex virus 1 (HSV-1 infection. CD200R1(-/- peritoneal macrophages demonstrated a 70-75% decrease in the generation of IL-6 and CCL5 (Rantes in response to the TLR2 agonist Pam(2CSK(4 and to HSV-1. CD200R1(-/- macrophages could neither up-regulate the expression of TLR2, nor assemble a functional inflammasome in response to HSV-1. CD200R1(-/- mice were protected from HSV-1 infection and exhibited dysfunctional TLR2 signaling. Finally, both CD200R1(-/- mice and CD200R1(-/- fibroblasts and macrophages showed a markedly reduced ability to support HSV-1 replication. In summary, our data demonstrate an unanticipated and novel requirement for CD200R1 in "licensing" pro-inflammatory functions of TLR2 and in limiting viral replication that are supported by ex vivo and in vivo evidence.

  6. Anthelmintic resistance in equine nematodes

    Directory of Open Access Journals (Sweden)

    Jacqueline B. Matthews

    2014-12-01

    Full Text Available Anthelmintics have been applied indiscriminately to control horse nematodes for over 40 years. Three broad-spectrum anthelmintic classes are currently registered for nematode control in horses: benzimidazoles (fenbendazole, oxibendazole, tetrahydropyrimidines (pyrantel and macrocyclic lactones (ivermectin, moxidectin. Generally, control strategies have focused on nematode egg suppression regimens that involve the frequent application of anthelmintics to all horses at intervals based on strongyle egg reappearance periods after treatment. The widespread use of such programmes has substantially reduced clinical disease, especially that associated with large strongyle species; however, high treatment frequency has led to considerable selection pressure for anthelmintic resistance, particularly in cyathostomin species. Field studies published over the last decade indicate that benzimidazole resistance is widespread globally in cyathostomins and there are also many reports of resistance to pyrantel in these worms. Cyathostomin resistance to macrocyclic lactone compounds is emerging, principally measured as a reduction in strongyle egg reappearance time observed after treatment. Ivermectin resistance is a further concern in the small intestinal nematode, Parascaris equorum, an important pathogen of foals. These issues indicate that horse nematodes must now be controlled using methods less dependent on anthelmintic use and more reliant on management practices designed to reduce the force of infection in the environment. Such strategies include improved grazing management integrated with targeted anthelmintic administration involving faecal egg count (FEC-directed treatments. The latter require that the supporting diagnostic tests available are robust and practically applicable. Recent research has focused on maximising the value of FEC analysis in horses and on optimizing protocols for anthelmintic efficacy testing. Other studies have sought to develop

  7. Internet delivered transdiagnostic treatment with telephone support for pain patients with emotional comorbidity: a replicated single case study

    Directory of Open Access Journals (Sweden)

    Matilda Wurm

    2017-12-01

    Full Text Available In pain patients, comorbid emotional problems have been linked to negative outcomes, including suboptimal treatment gains. Developing parsimonious and accessible treatment options is therefore important. The overarching aim of this study was to test an internet delivered therapist guided transdiagnostic treatment with telephone support. An adapted version of the Unified Protocol for Transdiagnostic Treatments of Emotional Disorders was used as an intervention for pain patients with residual pain problems and comorbid emotional problems after having received a multimodal pain rehabilitation. The study used a replicated AB single case experimental design (N = 5; 3 females. Outcome measures were depressive and general anxiety symptoms, pain intensity, pain coping problems, and diagnostic status. Feasibility measures (completion and compliance and patient satisfaction were also assessed. Scores on Nonoverlap of All Pairs (NAP indicate a decrease of anxiety for three participants and a decrease of depression for four participants. Decreases were small and did not always reach statistical significance. Also, Tau-U scores could only confirm a reliable trend for one participant. Two out of four patients who were diagnosed with psychiatric disorders before treatment did no longer fulfill diagnostic criteria posttreatment. No improvements could be seen on pain problems. The treatment was feasible and patient satisfaction was high. Hence, while an internet delivered transdiagnostic treatment with telephone support may be a feasible and accepted secondary intervention for pain patients with comorbid emotional problems, the effects are unclear. The gap between high patient satisfaction and small changes in symptomatology should be explored further.

  8. Nematode-Trapping Fungi.

    Science.gov (United States)

    Jiang, Xiangzhi; Xiang, Meichun; Liu, Xingzhong

    2017-01-01

    Nematode-trapping fungi are a unique and intriguing group of carnivorous microorganisms that can trap and digest nematodes by means of specialized trapping structures. They can develop diverse trapping devices, such as adhesive hyphae, adhesive knobs, adhesive networks, constricting rings, and nonconstricting rings. Nematode-trapping fungi have been found in all regions of the world, from the tropics to Antarctica, from terrestrial to aquatic ecosystems. They play an important ecological role in regulating nematode dynamics in soil. Molecular phylogenetic studies have shown that the majority of nematode-trapping fungi belong to a monophyletic group in the order Orbiliales (Ascomycota). Nematode-trapping fungi serve as an excellent model system for understanding fungal evolution and interaction between fungi and nematodes. With the development of molecular techniques and genome sequencing, their evolutionary origins and divergence, and the mechanisms underlying fungus-nematode interactions have been well studied. In recent decades, an increasing concern about the environmental hazards of using chemical nematicides has led to the application of these biological control agents as a rapidly developing component of crop protection.

  9. Ebola Virus Replication and Disease Without Immunopathology in Mice Expressing Transgenes to Support Human Myeloid and Lymphoid Cell Engraftment.

    Science.gov (United States)

    Spengler, Jessica R; Lavender, Kerry J; Martellaro, Cynthia; Carmody, Aaron; Kurth, Andreas; Keck, James G; Saturday, Greg; Scott, Dana P; Nichol, Stuart T; Hasenkrug, Kim J; Spiropoulou, Christina F; Feldmann, Heinz; Prescott, Joseph

    2016-10-15

    The study of Ebola virus (EBOV) pathogenesis in vivo has been limited to nonhuman primate models or use of an adapted virus to cause disease in rodent models. Herein we describe wild-type EBOV (Makona variant) infection of mice engrafted with human hematopoietic CD34 + stem cells (Hu-NSG™-SGM3 mice; hereafter referred to as SGM3 HuMice). SGM3 HuMice support increased development of myeloid immune cells, which are primary EBOV targets. In SGM3 HuMice, EBOV replicated to high levels, and disease was observed following either intraperitoneal or intramuscular inoculation. Despite the high levels of viral antigen and inflammatory cell infiltration in the liver, the characteristic histopathology of Ebola virus disease was not observed, and this absence of severe immunopathology may have contributed to the recovery and survival of some of the animals. Future investigations into the underlying mechanisms of the atypical disease presentation in SGM3 HuMice will provide additional insights into the immunopathogenesis of severe EBOV disease. Published by Oxford University Press for the Infectious Diseases Society of America 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  10. Phylogency and Evolution of Nematodes

    NARCIS (Netherlands)

    Bert, W.; Karssen, G.; Helder, J.

    2011-01-01

    Many plant-parasitic nematodes including members of the genera Meloidogyne (root-knot nematodes), Heterodera and Globodera (cyst nematodes) and Pratylenchus (lesion nematodes) are studied as they cause major damage to crops such as potato, tomato, soybean and sugar beet. Both for fundamental reasons

  11. Nematode effector proteins: an emerging paradigm of parasitism

    Science.gov (United States)

    Phytonematodes use a stylet and secreted effectors to invade host tissues and extract nutrients to support their growth and development. The molecular function of nematode effectors is currently the subject of intense investigation. In this review, we summarize our current understanding of nematode ...

  12. Variation in estuarine littoral nematode populations over three spatial scales

    Science.gov (United States)

    Hodda, M.

    1990-04-01

    The population characteristics of the nematode fauna from five replicate cores taken over four seasons at nine sites within mangroves, at three different estuaries on the south-east coast of Australia, are compared. Using cluster analysis, principal co-ordinate analysis and other statistical techniques, the variation in nematode populations is identified as arising from several sources: temperature changes between the more northerly and southerly estuaries (5%); changes in grain size and organic content of the sediment between sites (22%); changes between sites in the frequency of samples containing certain types of food, particularly associated with pools of water and surface topography (30%); stochastic changes in nematode populations within individual samples, probably caused by small scale spatial and temporal variability in food sources (35%); and seasonal changes at all the sites and estuaries (8%). The implications of this pattern of variation for the biology of the nematodes is discussed.

  13. The interactomes of influenza virus NS1 and NS2 proteins identify new host factors and provide insights for ADAR1 playing a supportive role in virus replication.

    Science.gov (United States)

    de Chassey, Benoît; Aublin-Gex, Anne; Ruggieri, Alessia; Meyniel-Schicklin, Laurène; Pradezynski, Fabrine; Davoust, Nathalie; Chantier, Thibault; Tafforeau, Lionel; Mangeot, Philippe-Emmanuel; Ciancia, Claire; Perrin-Cocon, Laure; Bartenschlager, Ralf; André, Patrice; Lotteau, Vincent

    2013-01-01

    Influenza A NS1 and NS2 proteins are encoded by the RNA segment 8 of the viral genome. NS1 is a multifunctional protein and a virulence factor while NS2 is involved in nuclear export of viral ribonucleoprotein complexes. A yeast two-hybrid screening strategy was used to identify host factors supporting NS1 and NS2 functions. More than 560 interactions between 79 cellular proteins and NS1 and NS2 proteins from 9 different influenza virus strains have been identified. These interacting proteins are potentially involved in each step of the infectious process and their contribution to viral replication was tested by RNA interference. Validation of the relevance of these host cell proteins for the viral replication cycle revealed that 7 of the 79 NS1 and/or NS2-interacting proteins positively or negatively controlled virus replication. One of the main factors targeted by NS1 of all virus strains was double-stranded RNA binding domain protein family. In particular, adenosine deaminase acting on RNA 1 (ADAR1) appeared as a pro-viral host factor whose expression is necessary for optimal viral protein synthesis and replication. Surprisingly, ADAR1 also appeared as a pro-viral host factor for dengue virus replication and directly interacted with the viral NS3 protein. ADAR1 editing activity was enhanced by both viruses through dengue virus NS3 and influenza virus NS1 proteins, suggesting a similar virus-host co-evolution.

  14. The interactomes of influenza virus NS1 and NS2 proteins identify new host factors and provide insights for ADAR1 playing a supportive role in virus replication.

    Directory of Open Access Journals (Sweden)

    Benoît de Chassey

    Full Text Available Influenza A NS1 and NS2 proteins are encoded by the RNA segment 8 of the viral genome. NS1 is a multifunctional protein and a virulence factor while NS2 is involved in nuclear export of viral ribonucleoprotein complexes. A yeast two-hybrid screening strategy was used to identify host factors supporting NS1 and NS2 functions. More than 560 interactions between 79 cellular proteins and NS1 and NS2 proteins from 9 different influenza virus strains have been identified. These interacting proteins are potentially involved in each step of the infectious process and their contribution to viral replication was tested by RNA interference. Validation of the relevance of these host cell proteins for the viral replication cycle revealed that 7 of the 79 NS1 and/or NS2-interacting proteins positively or negatively controlled virus replication. One of the main factors targeted by NS1 of all virus strains was double-stranded RNA binding domain protein family. In particular, adenosine deaminase acting on RNA 1 (ADAR1 appeared as a pro-viral host factor whose expression is necessary for optimal viral protein synthesis and replication. Surprisingly, ADAR1 also appeared as a pro-viral host factor for dengue virus replication and directly interacted with the viral NS3 protein. ADAR1 editing activity was enhanced by both viruses through dengue virus NS3 and influenza virus NS1 proteins, suggesting a similar virus-host co-evolution.

  15. Distributional Replication

    OpenAIRE

    Beare, Brendan K.

    2009-01-01

    Suppose that X and Y are random variables. We define a replicating function to be a function f such that f(X) and Y have the same distribution. In general, the set of replicating functions for a given pair of random variables may be infinite. Suppose we have some objective function, or cost function, defined over the set of replicating functions, and we seek to estimate the replicating function with the lowest cost. We develop an approach to estimating the cheapest replicating function that i...

  16. Replication Catastrophe

    DEFF Research Database (Denmark)

    Toledo, Luis; Neelsen, Kai John; Lukas, Jiri

    2017-01-01

    Proliferating cells rely on the so-called DNA replication checkpoint to ensure orderly completion of genome duplication, and its malfunction may lead to catastrophic genome disruption, including unscheduled firing of replication origins, stalling and collapse of replication forks, massive DNA...... breakage, and, ultimately, cell death. Despite many years of intensive research into the molecular underpinnings of the eukaryotic replication checkpoint, the mechanisms underlying the dismal consequences of its failure remain enigmatic. A recent development offers a unifying model in which the replication...... checkpoint guards against global exhaustion of rate-limiting replication regulators. Here we discuss how such a mechanism can prevent catastrophic genome disruption and suggest how to harness this knowledge to advance therapeutic strategies to eliminate cancer cells that inherently proliferate under...

  17. Nematode cholinergic pharmacology

    International Nuclear Information System (INIS)

    Segerberg, M.A.

    1989-01-01

    Nematode acetylcholine (ACh) receptors were characterized using both biochemical and electrophysiological techniques, including: (1) receptor binding studies in crude homogenates of the free-living nematode Caenorhabditis elegans and the parasitic nematode Ascaris lumbricoides with the high-affinity probe [ 3 H]N-methylscopolamine ([ 3 H]NMS) which binds to muscarinic receptors in many vertebrate and invertebrate tissues (2) measurement of depolarization and contraction induced by a variety of cholinergic agents, including N-methylscopolamine (NMS), in an innervated dorsal muscle strip preparation of Ascaris; (3) examination of the antagonistic actions of d-tubocurarine (dTC) and NMS at dorsal neuromuscular junction; (4) measurement of input resistance changes in Ascaris commissural motorneurons induced by ACh, dTC, NMS, pilocarpine and other cholinergic drugs

  18. Recombinant adeno-associated virus type 2 replication and packaging is entirely supported by a herpes simplex virus type 1 amplicon expressing Rep and Cap.

    Science.gov (United States)

    Conway, J E; Zolotukhin, S; Muzyczka, N; Hayward, G S; Byrne, B J

    1997-11-01

    Recombinant adeno-associated virus (AAV) type 2 (rAAV) vectors have recently been shown to have great utility as gene transfer agents both in vitro and in vivo. One of the problems associated with the use of rAAV vectors has been the difficulty of large-scale vector production. Low-efficiency plasmid transfection of the rAAV vector and complementing AAV type 2 (AAV-2) functions (rep and cap) followed by superinfection with adenovirus has been the standard approach to rAAV production. The objectives of this study were to demonstrate the ability of a recombinant herpes simplex virus type 1 (HSV-1) amplicon expressing AAV-2 Rep and Cap to support replication and packaging of rAAV vectors. HSV-1 amplicon vectors were constructed which contain the AAV-2 rep and cap genes under control of their native promoters (p5, p19, and p40). An HSV-1 amplicon vector, HSV-RC/KOS or HSV-RC/d27, was generated by supplying helper functions with either wild-type HSV-1 (KOS strain) or the ICP27-deleted mutant of HSV-1, d27-1, respectively. Replication of the amplicon stocks is not inhibited by the presence of AAV-2 Rep proteins, which highlights important differences between HSV-1 and adenovirus replication and the mechanism of providing helper function for productive AAV infection. Coinfection of rAAV and HSV-RC/KOS resulted in the replication and amplification of rAAV genomes. Similarly, rescue and replication of rAAV genomes occurred when rAAV vector plasmids were transfected into cells followed by HSV-RC/KOS infection and when two rAAV proviral cell lines were infected with HSV-RC/KOS or HSV-RC/d27. Production of infectious rAAV by rescue from two rAAV proviral cell lines has also been achieved with HSV-RC/KOS and HSV-RC/d27. The particle titer of rAAV produced with HSV-RC/d27 is equal to that achieved by supplying rep and cap by transfection followed by adenovirus superinfection. Importantly, no detectable wild-type AAV-2 is generated with this approach. These results demonstrate

  19. Human prostate supports more efficient replication of HIV-1 R5 than X4 strains ex vivo

    Directory of Open Access Journals (Sweden)

    Denis Hélène

    2008-12-01

    Full Text Available Abstract Background In order to determine whether human prostate can be productively infected by HIV-1 strains with different tropism, and thus represent a potential source of HIV in semen, an organotypic culture of prostate from men undergoing prostatic adenomectomy for benign prostate hypertrophy (BPH was developed. The presence of potential HIV target cells in prostate tissues was investigated using immunohistochemistry. The infection of prostate explants following exposures with HIV-1 R5, R5X4 and X4 strains was analyzed through the measure of RT activity in culture supernatants, the quantification of HIV DNA in the explants and the detection of HIV RNA+ cells in situ. Results The overall prostate characteristics were retained for 21/2 weeks in culture. Numerous potential HIV-1 target cells were detected in the prostate stroma. Whilst HIV-1 R5SF162 strain consistently productively infected prostatic T lymphocytes and macrophages, the prototypic X4IIIB strain and a primary R5X4 strain showed less efficient replication in this organ. Conclusion The BPH prostate is a site of HIV-1 R5 replication that could contribute virus to semen. A limited spreading of HIV-1 X4 and R5X4 in this organ could participate to the preferential sexual transmission of HIV-1 R5 strains.

  20. Database Replication

    CERN Document Server

    Kemme, Bettina

    2010-01-01

    Database replication is widely used for fault-tolerance, scalability and performance. The failure of one database replica does not stop the system from working as available replicas can take over the tasks of the failed replica. Scalability can be achieved by distributing the load across all replicas, and adding new replicas should the load increase. Finally, database replication can provide fast local access, even if clients are geographically distributed clients, if data copies are located close to clients. Despite its advantages, replication is not a straightforward technique to apply, and

  1. Potential Nematode Alarm Pheromone Induces Acute Avoidance in Caenorhabditis elegans.

    Science.gov (United States)

    Zhou, Ying; Loeza-Cabrera, Mario; Liu, Zheng; Aleman-Meza, Boanerges; Nguyen, Julie K; Jung, Sang-Kyu; Choi, Yuna; Shou, Qingyao; Butcher, Rebecca A; Zhong, Weiwei

    2017-07-01

    It is crucial for animal survival to detect dangers such as predators. A good indicator of dangers is injury of conspecifics. Here we show that fluids released from injured conspecifics invoke acute avoidance in both free-living and parasitic nematodes. Caenorhabditis elegans avoids extracts from closely related nematode species but not fruit fly larvae. The worm extracts have no impact on animal lifespan, suggesting that the worm extract may function as an alarm instead of inflicting physical harm. Avoidance of the worm extract requires the function of a cGMP signaling pathway that includes the cGMP-gated channel TAX-2/TAX-4 in the amphid sensory neurons ASI and ASK. Genetic evidence indicates that the avoidance behavior is modulated by the neurotransmitters GABA and serotonin, two common targets of anxiolytic drugs. Together, these data support a model that nematodes use a nematode-specific alarm pheromone to detect conspecific injury. Copyright © 2017 by the Genetics Society of America.

  2. Eukaryotic DNA Replication Fork.

    Science.gov (United States)

    Burgers, Peter M J; Kunkel, Thomas A

    2017-06-20

    This review focuses on the biogenesis and composition of the eukaryotic DNA replication fork, with an emphasis on the enzymes that synthesize DNA and repair discontinuities on the lagging strand of the replication fork. Physical and genetic methodologies aimed at understanding these processes are discussed. The preponderance of evidence supports a model in which DNA polymerase ε (Pol ε) carries out the bulk of leading strand DNA synthesis at an undisturbed replication fork. DNA polymerases α and δ carry out the initiation of Okazaki fragment synthesis and its elongation and maturation, respectively. This review also discusses alternative proposals, including cellular processes during which alternative forks may be utilized, and new biochemical studies with purified proteins that are aimed at reconstituting leading and lagging strand DNA synthesis separately and as an integrated replication fork.

  3. Psychometric support of the school climate measure in a large, diverse sample of adolescents: a replication and extension.

    Science.gov (United States)

    Zullig, Keith J; Collins, Rani; Ghani, Nadia; Patton, Jon M; Scott Huebner, E; Ajamie, Jean

    2014-02-01

    The School Climate Measure (SCM) was developed and validated in 2010 in response to a dearth of psychometrically sound school climate instruments. This study sought to further validate the SCM on a large, diverse sample of Arizona public school adolescents (N = 20,953). Four SCM domains (positive student-teacher relationships, academic support, order and discipline, and physical environment) were available for the analysis. Confirmatory factor analysis and structural equation modeling were established to construct validity, and criterion-related validity was assessed via selected Youth Risk Behavior Survey (YRBS) school safety items and self-reported grade (GPA) point average. Analyses confirmed the 4 SCM school climate domains explained approximately 63% of the variance (factor loading range .45-.92). Structural equation models fit the data well χ(2) = 14,325 (df = 293, p < .001), comparative fit index (CFI) = .951, Tuker-Lewis index (TLI) = .952, root mean square error of approximation (RMSEA) = .05). The goodness-of-fit index was .940. Coefficient alphas ranged from .82 to .93. Analyses of variance with post hoc comparisons suggested the SCM domains related in hypothesized directions with the school safety items and GPA. Additional evidence supports the validity and reliability of the SCM. Measures, such as the SCM, can facilitate data-driven decisions and may be incorporated into evidenced-based processes designed to improve student outcomes. © 2014, American School Health Association.

  4. Effect of the spray application technique on the deposition of entomopathogenic nematodes in vegetables.

    Science.gov (United States)

    Brusselman, Eva; Beck, Bert; Pollet, Sabien; Temmerman, Femke; Spanoghe, Pieter; Moens, Maurice; Nuyttens, David

    2012-03-01

    The present study compared entomopathogenic nematode delivery at the base of savoy cabbage and cauliflower, at the lower side of savoy cabbage and cauliflower leaves and in leek stems and the ground deposition using a five-nozzle spray boom equipped with an ISO 08 flat fan, an air induction flat fan and Twinjet spray nozzles. Additionally, an air support system and a row application system were evaluated. Approximately 40% of the applied nematodes did not reach the foot of the cabbage plants. The use of an air support system or a row application system improved nematode deposition at the savoy cabbage base. Relative nematode deposition on the lower side of savoy cabbage leaves was 27.20%, while only 2.64% of the applied nematodes reached the lower side of cauliflower leaves. After spraying leek with a standard boom, a low relative nematode deposition (26.64%) was measured in the leek stem. Nozzle type affected the distribution of nematodes in droplet spots. Nozzle type has a minor effect on the number of entomopathogenic nematodes delivered on difficult-to-reach targets. The use of modified spray application techniques directing the spray to the target site are necessary to increase the chances of contact of entomopathogenic nematodes with their target. Copyright © 2011 Society of Chemical Industry.

  5. Yeast replicative aging: a paradigm for defining conserved longevity interventions

    OpenAIRE

    Wasko, Brian M.; Kaeberlein, Matt

    2013-01-01

    The finite replicative life span of budding yeast mother cells was demonstrated as early as 1959, but the idea that budding yeast could be used to model aging of multicellular eukaryotes did not enter the scientific mainstream until relatively recently. Despite continued skepticism by some, there are now abundant data that several interventions capable of extending yeast replicative life span have a similar effect in multicellular eukaryotes including nematode worms, fruit flies, and rodents....

  6. Replication of genome wide association studies of alcohol dependence: support for association with variation in ADH1C.

    Directory of Open Access Journals (Sweden)

    Joanna M Biernacka

    Full Text Available Genome-wide association studies (GWAS have revealed many single nucleotide polymorphisms (SNPs associated with complex traits. Although these studies frequently fail to identify statistically significant associations, the top association signals from GWAS may be enriched for true associations. We therefore investigated the association of alcohol dependence with 43 SNPs selected from association signals in the first two published GWAS of alcoholism. Our analysis of 808 alcohol-dependent cases and 1,248 controls provided evidence of association of alcohol dependence with SNP rs1614972 in the ADH1C gene (unadjusted p = 0.0017. Because the GWAS study that originally reported association of alcohol dependence with this SNP [1] included only men, we also performed analyses in sex-specific strata. The results suggest that this SNP has a similar effect in both sexes (men: OR (95%CI = 0.80 (0.66, 0.95; women: OR (95%CI = 0.83 (0.66, 1.03. We also observed marginal evidence of association of the rs1614972 minor allele with lower alcohol consumption in the non-alcoholic controls (p = 0.081, and independently in the alcohol-dependent cases (p = 0.046. Despite a number of potential differences between the samples investigated by the prior GWAS and the current study, data presented here provide additional support for the association of SNP rs1614972 in ADH1C with alcohol dependence and extend this finding by demonstrating association with consumption levels in both non-alcoholic and alcohol-dependent populations. Further studies should investigate the association of other polymorphisms in this gene with alcohol dependence and related alcohol-use phenotypes.

  7. Heterodera schachtii Tyrosinase-like protein a novel nematode effector modulating plant hormone homeostasis

    Czech Academy of Sciences Publication Activity Database

    Habash, S.; Radakovic, Z.S.; Vaňková, Radomíra; Siddique, S.; Dobrev, Petre; Gleason, C.; Grundler, F.M.W.; Elashry, A.

    2017-01-01

    Roč. 7, JUL 31 (2017), č. článku 6874. ISSN 2045-2322 Institutional support: RVO:61389030 Keywords : arabidopsis-thaliana * cyst-nematode * parasitic nematode * transient expression * host plants * sequence * identification * infection * model * transformation Subject RIV: ED - Physiology OBOR OECD: Plant sciences, botany Impact factor: 4.259, year: 2016

  8. Molecular aspects of cyst nematodes.

    Science.gov (United States)

    Lilley, Catherine J; Atkinson, Howard J; Urwin, Peter E

    2005-11-01

    SUMMARY Taxonomy: Superkingdom Eukaryota; kingdom Metazoa; phylum Nematoda; class Chromadorea; order Tylenchida; suborder Tylenchina; superfamily Tylenchoidea; family Heteroderidae; subfamily Heteroderinae; main genera Heterodera and Globodera. Cyst nematodes comprise approximately 100 known species in six genera. They are pathogens of temperate, subtropical and tropical plant species and the host range of many species is narrow. The most economically important species are within the Globodera and Heterodera genera. Globodera pallida and G. rostochiensis are important pathogens of potato crops. There are many economic species in the Heterodera genus, including Heterodera glycines (soybean cyst nematode), H. avenae (cereal cyst nematode) and H. schachtii (sugar beet cyst nematode), the last of which attacks a range of Chenopodiaceae and Cruciferae, including Arabidopsis thaliana. Disease symptoms: Field symptoms of severe cyst nematode infection are often stunting, wilting and chlorosis, but considerable yield loss can occur without obvious symptoms. The only unique indicator of cyst nematode infection is the presence of adult female nematodes attached to host roots after several weeks of parasitism. Disease control: This is usually achieved by using integrated pest management involving cultural practices such as crop rotation, resistant cultivars if available and chemical control when economically justified.

  9. The pinewood nematode, Bursaphelenchus xylophilus

    OpenAIRE

    Mota, Manuel; Vieira, Paulo

    2004-01-01

    According to the European Plant Protection Organization, the pinewood nematode (PWN), Bursaphelenchus xylophilus is a quarantine organism at the top of the list of the pathogenic species. PWN may be found in North America (Canada, USA and Mexico) and in East Asia (Japan, Korea, China and Taiwan) and has a highly destructive capability towards conifers, in a relatively short time, causing serious economic damage in Japan, China and Korea. This nematode surveying is extremely imp...

  10. In Vivo Production of Entomopathogenic Nematodes.

    Science.gov (United States)

    Shapiro-Ilan, David I; Morales-Ramos, Juan A; Rojas, M Guadalupe

    2016-01-01

    In nature, entomopathogenic nematodes in the genera Heterorhabditis and Steinernema are obligate parasites of insects. The nematodes are used widely as biopesticides for suppression of insect pests. More than a dozen entomopathogenic nematode species have been commercialized for use in biological control. Most nematodes intended for commercial application are produced in artificial media via solid or liquid fermentation. However, for laboratory research and small greenhouse or field trials, in vivo production of entomopathogenic nematodes is the common method of propagation. Additionally, small companies continue to produce nematodes using in vivo methods for application in niche markets. Advances in mechanization and alternative production routes (e.g., production geared toward application of nematodes in infected host cadavers) can improve efficiency and economy of scale. The objective of this chapter is to describe basic and advanced procedures for in vivo production of entomopathogenic nematodes.

  11. Basic and applied research: Entomopathogenic nematodes

    Science.gov (United States)

    Entomopathogenic nematodes in the genera Heterorhabditis and Steinernema kill arthropods with the aid of their bacterial symbionts. These nematodes are potent microbial control agents that have been widely commercialized for control of economically important insect pests. Biocontrol efficacy relies...

  12. Nematode neuropeptides as transgenic nematicides.

    Directory of Open Access Journals (Sweden)

    Neil D Warnock

    2017-02-01

    Full Text Available Plant parasitic nematodes (PPNs seriously threaten global food security. Conventionally an integrated approach to PPN management has relied heavily on carbamate, organophosphate and fumigant nematicides which are now being withdrawn over environmental health and safety concerns. This progressive withdrawal has left a significant shortcoming in our ability to manage these economically important parasites, and highlights the need for novel and robust control methods. Nematodes can assimilate exogenous peptides through retrograde transport along the chemosensory amphid neurons. Peptides can accumulate within cells of the central nerve ring and can elicit physiological effects when released to interact with receptors on adjoining cells. We have profiled bioactive neuropeptides from the neuropeptide-like protein (NLP family of PPNs as novel nematicides, and have identified numerous discrete NLPs that negatively impact chemosensation, host invasion and stylet thrusting of the root knot nematode Meloidogyne incognita and the potato cyst nematode Globodera pallida. Transgenic secretion of these peptides from the rhizobacterium, Bacillus subtilis, and the terrestrial microalgae Chlamydomonas reinhardtii reduce tomato infection levels by up to 90% when compared with controls. These data pave the way for the exploitation of nematode neuropeptides as a novel class of plant protective nematicide, using novel non-food transgenic delivery systems which could be deployed on farmer-preferred cultivars.

  13. Nematode suppression and growth stimulation in corn plants (Zea mays L.) irrigated with domestic effluent.

    Science.gov (United States)

    Barros, Kenia Kelly; do Nascimento, Clístenes Williams Araújo; Florencio, Lourdinha

    2012-01-01

    Treated wastewater has great potential for agricultural use due to its concentrations of nutrients and organic matter, which are capable of improving soil characteristics. Additionally, effluents can induce suppression of plant diseases caused by soil pathogens. This study evaluates the effect of irrigation with effluent in a UASB reactor on maize (Zea mays L.) development and on suppression of the diseases caused by nematodes of the genus Meloidogyne. Twelve lysimeters of 1 m(3) each were arranged in a completely randomized design, with four treatments and three replicates. The following treatments were used: T1 (W+I), irrigation with water and infestation with nematodes; T2 (W+I+NPK), irrigation with water, infestation with nematodes and fertilization with nitrogen (N), phosphorus (P) and potassium (K); T3 (E+I), irrigation with effluent and infestation with nematodes; and T4 (E+I+P), irrigation with effluent, infestation with nematodes and fertilization with phosphorus. The plants irrigated with the effluent plus the phosphorus fertilizer had better growth and productivity and were more resistant to the disease symptoms caused by the nematodes. The suppression levels may have been due to the higher levels of Zn and NO(3)(-) found in the leaf tissue of the plants irrigated with the effluent and phosphorus fertilizer.

  14. The complete mitochondrial genomes of three parasitic nematodes of birds: a unique gene order and insights into nematode phylogeny

    Science.gov (United States)

    2013-01-01

    Background Analyses of mitochondrial (mt) genome sequences in recent years challenge the current working hypothesis of Nematoda phylogeny proposed from morphology, ecology and nuclear small subunit rRNA gene sequences, and raise the need to sequence additional mt genomes for a broad range of nematode lineages. Results We sequenced the complete mt genomes of three Ascaridia species (family Ascaridiidae) that infest chickens, pigeons and parrots, respectively. These three Ascaridia species have an identical arrangement of mt genes to each other but differ substantially from other nematodes. Phylogenetic analyses of the mt genome sequences of the Ascaridia species, together with 62 other nematode species, support the monophylies of seven high-level taxa of the phylum Nematoda: 1) the subclass Dorylaimia; 2) the orders Rhabditida, Trichinellida and Mermithida; 3) the suborder Rhabditina; and 4) the infraorders Spiruromorpha and Oxyuridomorpha. Analyses of mt genome sequences, however, reject the monophylies of the suborders Spirurina and Tylenchina, and the infraorders Rhabditomorpha, Panagrolaimomorpha and Tylenchomorpha. Monophyly of the infraorder Ascaridomorpha varies depending on the methods of phylogenetic analysis. The Ascaridomorpha was more closely related to the infraorders Rhabditomorpha and Diplogasteromorpha (suborder Rhabditina) than they were to the other two infraorders of the Spirurina: Oxyuridorpha and Spiruromorpha. The closer relationship among Ascaridomorpha, Rhabditomorpha and Diplogasteromorpha was also supported by a shared common pattern of mitochondrial gene arrangement. Conclusions Analyses of mitochondrial genome sequences and gene arrangement has provided novel insights into the phylogenetic relationships among several major lineages of nematodes. Many lineages of nematodes, however, are underrepresented or not represented in these analyses. Expanding taxon sampling is necessary for future phylogenetic studies of nematodes with mt genome

  15. Plant-parasitic nematodes in Hawaiian agriculture

    Science.gov (United States)

    Hawaii’s diverse and mild climate allows for the cultivation of many crops. The introduction of each crop plant brought along its associated nematode pests. These plant-parasitic nematodes became established and are now endemic to the islands. Plantation agriculture determined the major nematode ...

  16. Entomopathogenic nematodes for the biocontrol of ticks.

    Science.gov (United States)

    Samish, M; Glazer, I

    2001-08-01

    Entomopathogenic steinemematid and heterorhabditid nematodes are increasingly used to control insect pests of economically important crops. Laboratory and field simulation trials show that ticks are also susceptible to these nematodes. The authors review the potential of entomogenous nematodes for the control of ticks.

  17. EFFECT OF SOIL FERTILITY MANAGEMENT PRACTICES ON NEMATODE DESTROYING FUNGI IN TAITA, KENYA

    Directory of Open Access Journals (Sweden)

    Peter M Wachira

    2010-10-01

    Full Text Available The effect of soil fertility management practices on nematode destroying fungi was investigated for three seasons in Taita, Kenya. The study aimed at identifying soil fertility practice that promoted nematode destroying fungi in the soil. Field experiments were established in Taita district, the treatments comprised of Mavuno fertilizer, Triple super- phosphate and calcium ammonium nitrate (TSP+CAN, cow manure and a control where no amendments were applied. This experiment was replicated in ten farms and repeated in three planting seasons. Isolation of nematode destroying fungi carried out was using the soil sprinkle technique and the isolates were identified using the key described by Cooke and Godfrey (1964. There were significant difference (P= 1.705 x 10-06 in occurrence of the nematode destroying fungi between soil fertility treatments. The highest mean (1.6 occurrence of nematode destroying fungi was recorded in soils amended with cow manure and the least (0.7 was recorded in soils from the control plots. A mean of 0.78 was recorded in soils from both TSP+CAN and Mavuno fertilizers. Plots amended with cow manure presented the highest diversity of nematodes followed by the control, then TSP+CAN and least in Mavuno with shannon indices of 0.34, 0.15, 0.13 and 0.11 respectively. Sixty percent of all the isolated nematode destroying fungi genera were from plots treated with cow manure and only twenty percent were from plots amended with the inorganic fertilizer. The control plots recorded higher number of nematode destroying fungi compared to the soils that received inorganic fertilizers.

  18. Nematode spatial and ecological patterns from tropical and temperate rainforests.

    Directory of Open Access Journals (Sweden)

    Dorota L Porazinska

    Full Text Available Large scale diversity patterns are well established for terrestrial macrobiota (e.g. plants and vertebrates, but not for microscopic organisms (e.g. nematodes. Due to small size, high abundance, and extensive dispersal, microbiota are assumed to exhibit cosmopolitan distributions with no biogeographical patterns. This assumption has been extrapolated from local spatial scale studies of a few taxonomic groups utilizing morphological approaches. Recent molecularly-based studies, however, suggest something quite opposite. Nematodes are the most abundant metazoans on earth, but their diversity patterns are largely unknown. We conducted a survey of nematode diversity within three vertical strata (soil, litter, and canopy of rainforests at two contrasting latitudes in the North American meridian (temperate: the Olympic National Forest, WA, U.S.A and tropical: La Selva Biological Station, Costa Rica using standardized sampling designs and sample processing protocols. To describe nematode diversity, we applied an ecometagenetic approach using 454 pyrosequencing. We observed that: 1 nematode communities were unique without even a single common species between the two rainforests, 2 nematode communities were unique among habitats in both rainforests, 3 total species richness was 300% more in the tropical than in the temperate rainforest, 4 80% of the species in the temperate rainforest resided in the soil, whereas only 20% in the tropics, 5 more than 90% of identified species were novel. Overall, our data provided no support for cosmopolitanism at both local (habitats and large (rainforests spatial scales. In addition, our data indicated that biogeographical patterns typical of macrobiota also exist for microbiota.

  19. Nematode Spatial and Ecological Patterns from Tropical and Temperate Rainforests

    Science.gov (United States)

    Porazinska, Dorota L.; Giblin-Davis, Robin M.; Powers, Thomas O.; Thomas, W. Kelley

    2012-01-01

    Large scale diversity patterns are well established for terrestrial macrobiota (e.g. plants and vertebrates), but not for microscopic organisms (e.g. nematodes). Due to small size, high abundance, and extensive dispersal, microbiota are assumed to exhibit cosmopolitan distributions with no biogeographical patterns. This assumption has been extrapolated from local spatial scale studies of a few taxonomic groups utilizing morphological approaches. Recent molecularly-based studies, however, suggest something quite opposite. Nematodes are the most abundant metazoans on earth, but their diversity patterns are largely unknown. We conducted a survey of nematode diversity within three vertical strata (soil, litter, and canopy) of rainforests at two contrasting latitudes in the North American meridian (temperate: the Olympic National Forest, WA, U.S.A and tropical: La Selva Biological Station, Costa Rica) using standardized sampling designs and sample processing protocols. To describe nematode diversity, we applied an ecometagenetic approach using 454 pyrosequencing. We observed that: 1) nematode communities were unique without even a single common species between the two rainforests, 2) nematode communities were unique among habitats in both rainforests, 3) total species richness was 300% more in the tropical than in the temperate rainforest, 4) 80% of the species in the temperate rainforest resided in the soil, whereas only 20% in the tropics, 5) more than 90% of identified species were novel. Overall, our data provided no support for cosmopolitanism at both local (habitats) and large (rainforests) spatial scales. In addition, our data indicated that biogeographical patterns typical of macrobiota also exist for microbiota. PMID:22984536

  20. Predator-prey interactions of nematode-trapping fungi and nematodes: both sides of the coin.

    Science.gov (United States)

    Vidal-Diez de Ulzurrun, Guillermo; Hsueh, Yen-Ping

    2018-05-01

    Nematode-trapping fungi develop complex trapping devices to capture and consume nematodes. The dynamics of these organisms is especially important given the pathogenicity of nematodes and, consequently, the potential application of nematode-trapping fungi as biocontrol agents. Furthermore, both the nematodes and nematode-trapping fungi can be easily grown in laboratories, making them a unique manipulatable predator-prey system to study their coevolution. Several different aspects of these fungi have been studied, such as their genetics and the different factors triggering trap formation. In this review, we use the nematode-trapping fungus Arthrobotrys oligospora (which forms adhesive nets) as a model to describe the trapping process. We divide this process into several stages; namely attraction, recognition, trap formation, adhesion, penetration, and digestion. We summarize the latest findings in the field and current knowledge on the interactions between nematodes and nematode-trapping fungi, representing both sides of the predator-prey interaction.

  1. Entomopathogenic nematodes in the European biocontrol market.

    Science.gov (United States)

    Ehlers, R U

    2003-01-01

    In Europe total revenues in the biocontrol market have reached approximately 200 million Euros. The sector with the highest turn-over is the market for beneficial invertebrates with a 55% share, followed by microbial agents with approximately 25%. Annual growth rates of up to 20% have been estimated. Besides microbial plant protection products that are currently in the process of re-registration, several microbial products have been registered or are in the process of registration, following the EU directive 91/414. Entomopathogenic nematodes (EPN) are exceptionally safe biocontrol agents. Until today, they are exempted from registration in most European countries, the reason why SMEs were able to offer economically reasonable nematode-based products. The development of technology for mass production in liquid media significantly reduced the product costs and accelerated the introduction of nematode products in tree nurseries, ornamentals, strawberries, mushrooms, citrus and turf. Progress in storage and formulation technology has resulted in high quality products which are more resistant to environmental extremes occurring during transportation to the user. The cooperation between science, industry and extension within the EU COST Action 819 has supported the development of quality control methods. Today four companies produce EPN in liquid culture, offering 8 different nematode species. Problems with soil insects are increasing. Grubs, like Melolontha melolontha and other scarabaeidae cause damage in orchards and turf. Since the introduction of the Western Corn Rootworm Diabrotica virgifera into Serbia in 1992, this pests as spread all over the Balkan Region and has reached Italy, France and Austria. These soil insect pests are potential targets for EPN. The development of insecticide resistance has opened another sector for EPN. Novel adjuvants used to improve formulation of EPN have enabled the foliar application against Western Flower Thrips and Plutella

  2. Olfactory circuits and behaviors of nematodes.

    Science.gov (United States)

    Rengarajan, Sophie; Hallem, Elissa A

    2016-12-01

    Over one billion people worldwide are infected with parasitic nematodes. Many parasitic nematodes actively search for hosts to infect using volatile chemical cues, so understanding the olfactory signals that drive host seeking may elucidate new pathways for preventing infections. The free-living nematode Caenorhabditis elegans is a powerful model for parasitic nematodes: because sensory neuroanatomy is conserved across nematode species, an understanding of the microcircuits that mediate olfaction in C. elegans may inform studies of olfaction in parasitic nematodes. Here we review circuit mechanisms that allow C. elegans to respond to odorants, gases, and pheromones. We also highlight work on the olfactory behaviors of parasitic nematodes that lays the groundwork for future studies of their olfactory microcircuits. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Database Replication Prototype

    OpenAIRE

    Vandewall, R.

    2000-01-01

    This report describes the design of a Replication Framework that facilitates the implementation and com-parison of database replication techniques. Furthermore, it discusses the implementation of a Database Replication Prototype and compares the performance measurements of two replication techniques based on the Atomic Broadcast communication primitive: pessimistic active replication and optimistic active replication. The main contributions of this report can be split into four parts....

  4. Immunity to gastrointestinal nematode infections

    DEFF Research Database (Denmark)

    Sorobetea, D.; Svensson Frej, M.; Grencis, R.

    2018-01-01

    Numerous species of nematodes have evolved to inhabit the gastrointestinal tract of animals and humans, with over a billion of the world's population infected with at least one species. These large multicellular pathogens present a considerable and complex challenge to the host immune system give...

  5. Functionality of resistance gene Hero, which controls plant root-infecting potato cyst nematodes, in leaves of tomato.

    Science.gov (United States)

    Poch, H L Cabrera; López, R H Manzanilla; Kanyuka, K

    2006-07-01

    The expression of host genomes is modified locally by root endoparasitic nematode secretions to induce the development of complex cellular structures referred as feeding sites. In compatible interactions, the feeding sites provide the environment and nutrients for the completion of the nematode's life cycle, whereas in an incompatible (resistant) interaction, the host immune system triggers a plant cell death programme, often in the form of a hypersensitive reaction, which restricts nematode reproduction. These processes have been studied in great detail in organ tissues normally infected by these nematodes: the roots. Here we show that host leaves can support a similar set of programmed developmental events in the potato cyst nematode Globodera rostochiensis life cycle that are typical of the root-invading nematodes. We also show that a gene-for-gene type specific disease resistance that is effective against potato cyst nematodes (PCN) in roots also operates in leaves: the expression of the resistance (R) gene Hero and members of its gene family in leaves correlates with the elicitation of a hypersensitive response only during the incompatible interaction. These findings, and the ability to isolate RNA from relevant parasitic stages of the nematode, may have significant implications for the identification of nematode factors involved in incompatible interactions.

  6. Conflict of interest between a nematode and a trematode in an amphipod host: Test of the "sabotage" hypothesis

    Science.gov (United States)

    Thomas, Frédéric; Fauchier, Jerome; Lafferty, Kevin D.

    2002-01-01

    Microphallus papillorobustus is a manipulative trematode that induces strong behavioural alterations in the gamaridean amphipod Gammarus insensibilis, making the amphipod more vulnerable to predation by aquatic birds (definitive hosts). Conversely, the sympatric nematodeGammarinema gammari uses Gammarus insensibilis as a habitat and a source of nutrition. We investigated the conflict of interest between these two parasite species by studying the consequences of mixed infection on amphipod behaviour associated with the trematode. In the field, some amphipods infected by the trematode did not display the altered behaviour. These normal amphipods also had more nematodes, suggesting that the nematode overpowered the manipulation of the trematode, a strategy that would prolong the nematode's life. We hypothesize that sabotage of the trematode by the nematode would be an adaptive strategy for the nematode consistent with recent speculation about co-operation and conflict in manipulative parasites. A behavioural test conducted in the laboratory from naturally infected amphipods yielded the same result. However, exposing amphipods to nematodes did not negate or decrease the manipulation exerted by the trematode. Similarly, experimental elimination of nematodes from amphipods did not permit trematodes to manipulate behaviour. These experimental data do not support the hypothesis that the negative association between nematodes and manipulation by the trematode is a result of the "sabotage" hypothesis.

  7. A large replication study and meta-analysis in European samples provides further support for association of AHI1 markers with schizophrenia

    DEFF Research Database (Denmark)

    Ingason, Andrés; Giegling, Ina; Cichon, Sven

    2010-01-01

    The Abelson helper integration site 1 (AHI1) gene locus on chromosome 6q23 is among a group of candidate loci for schizophrenia susceptibility that were initially identified by linkage followed by linkage disequilibrium mapping, and subsequent replication of the association in an independent sample....... Here, we present results of a replication study of AHI1 locus markers, previously implicated in schizophrenia, in a large European sample (in total 3907 affected and 7429 controls). Furthermore, we perform a meta-analysis of the implicated markers in 4496 affected and 18,920 controls. Both...... as the neighbouring phosphodiesterase 7B (PDE7B)-may be considered candidates for involvement in the genetic aetiology of schizophrenia....

  8. Prelife catalysts and replicators

    OpenAIRE

    Ohtsuki, Hisashi; Nowak, Martin A.

    2009-01-01

    Life is based on replication and evolution. But replication cannot be taken for granted. We must ask what there was prior to replication and evolution. How does evolution begin? We have proposed prelife as a generative system that produces information and diversity in the absence of replication. We model prelife as a binary soup of active monomers that form random polymers. ‘Prevolutionary’ dynamics can have mutation and selection prior to replication. Some sequences might have catalytic acti...

  9. Biocontrol: Fungal Parasites of Female Cyst Nematodes

    OpenAIRE

    Kerry, Brian

    1980-01-01

    Three species of fungi, Catenaria auxiliarls (Kühn) Tribe, Nematophthora gynophila Kerry and Crump, and a Lagenidiaceous fungus have been found attacking female cyst nematodes. All are zoosporic fungi which parasitize females on the root surface, cause the breakdown of the nematode cuticle, and prevent cyst formation. Their identification and some aspects of their biology are reviewed. N. gynophila is widespread in Britain and reduces populations of the cereal cyst nematode, Heterodera avenae...

  10. Epidemiological studies of nematodes in fishes

    International Nuclear Information System (INIS)

    Qamar, M.F.; Butt, K.; Qureshi, N.A.

    2014-01-01

    Three hundred fresh water fishes of six species were collected from six different fish farms of Lahore for the prevalence of nematodes. Out of 300 fishes examined, 12 were found to be infected with the helminthes, majority of them were isolated from the stomach and intestines. The following two species of nematodes were recorded; Capillaria spp. and Eustrongylides spp. The overall prevalence of intestinal nematodes was recorded as 4%(12/300). The prevalence of nematodes was recorded on monthly basis which ranged from 0-8%. The highest prevalence of nematodes was 8% (4/50) during March, while the lowest prevalence was noted in June 0%.Singharee (Sperata sawari) showed the maximum infestation of nematodes of 8% (4/50), whereas in Silver Carp (Hypopthaimichthys molitrix) minimum prevalence of nematode (0%) was noted. The prevalence of different nematode in a particular fish specie was also recorded, and it was stated that overall prevalence of capillaria spp. was 6% in Rahu (Labeo rohita) and Saul (Channa marullius). Similarly overall infestation of Eustrongylides sp. was recorded as 4% in Singharee (Sperata sawari) and Silver carp (Hypopthaimichthys molitrix). The nematode intensity might be linked with the genetic makeup, intestinal vigor, and other managemental and environmental factors. (author)

  11. STAT2 Knockout Syrian Hamsters Support Enhanced Replication and Pathogenicity of Human Adenovirus, Revealing an Important Role of Type I Interferon Response in Viral Control.

    Directory of Open Access Journals (Sweden)

    Karoly Toth

    2015-08-01

    Full Text Available Human adenoviruses have been studied extensively in cell culture and have been a model for studies in molecular, cellular, and medical biology. However, much less is known about adenovirus replication and pathogenesis in vivo in a permissive host because of the lack of an adequate animal model. Presently, the most frequently used permissive immunocompetent animal model for human adenovirus infection is the Syrian hamster. Species C human adenoviruses replicate in these animals and cause pathology that is similar to that seen with humans. Here, we report findings with a new Syrian hamster strain in which the STAT2 gene was functionally knocked out by site-specific gene targeting. Adenovirus-infected STAT2 knockout hamsters demonstrated an accentuated pathology compared to the wild-type control animals, and the virus load in the organs of STAT2 knockout animals was 100- to 1000-fold higher than that in wild-type hamsters. Notably, the adaptive immune response to adenovirus is not adversely affected in STAT2 knockout hamsters, and surviving hamsters cleared the infection by 7 to 10 days post challenge. We show that the Type I interferon pathway is disrupted in these hamsters, revealing the critical role of interferon-stimulated genes in controlling adenovirus infection. This is the first study to report findings with a genetically modified Syrian hamster infected with a virus. Further, this is the first study to show that the Type I interferon pathway plays a role in inhibiting human adenovirus replication in a permissive animal model. Besides providing an insight into adenovirus infection in humans, our results are also interesting from the perspective of the animal model: STAT2 knockout Syrian hamster may also be an important animal model for studying other viral infections, including Ebola-, hanta-, and dengue viruses, where Type I interferon-mediated innate immunity prevents wild type hamsters from being effectively infected to be used as

  12. Soil Nematodes and Their Prokaryotic Prey Along an Elevation Gradient in The Mojave Desert (Death Valley National Park, California, USA

    Directory of Open Access Journals (Sweden)

    Alyxandra Pikus

    2012-10-01

    Full Text Available We characterized soil communities in the Mojave Desert across an elevation gradient. Our goal was to test the hypothesis that as soil quality improved with increasing elevation (due to increased productivity, the diversity of soil prokaryotes and nematodes would also increase. Soil organic matter and soil moisture content increased with elevation as predicted. Soil salinity did not correlate to elevation, but was highest at a mid-gradient, alluvial site. Soil nematode density, community trophic structure, and diversity did not show patterns related to elevation. Similar results were obtained for diversity of bacteria and archaea. Relationships between soil properties, nematode communities, and prokaryotic diversity were site-specific. For example, at the lowest elevation site, nematode communities contained a high proportion of fungal-feeding species and diversity of bacteria was lowest. At a high-salinity site, nematode density was highest, and overall, nematode density showed an unexpected, positive correlation to salinity. At the highest elevation site, nematode density and species richness were attenuated, despite relatively high moisture and organic matter content for the soils. Our results support emerging evidence for the lack of a relationship between productivity and the diversity of soil nematodes and prokaryotes.

  13. Mechanisms of host seeking by parasitic nematodes.

    Science.gov (United States)

    Gang, Spencer S; Hallem, Elissa A

    2016-07-01

    The phylum Nematoda comprises a diverse group of roundworms that includes parasites of vertebrates, invertebrates, and plants. Human-parasitic nematodes infect more than one billion people worldwide and cause some of the most common neglected tropical diseases, particularly in low-resource countries [1]. Parasitic nematodes of livestock and crops result in billions of dollars in losses each year [1]. Many nematode infections are treatable with low-cost anthelmintic drugs, but repeated infections are common in endemic areas and drug resistance is a growing concern with increasing therapeutic and agricultural administration [1]. Many parasitic nematodes have an environmental infective larval stage that engages in host seeking, a process whereby the infective larvae use sensory cues to search for hosts. Host seeking is a complex behavior that involves multiple sensory modalities, including olfaction, gustation, thermosensation, and humidity sensation. As the initial step of the parasite-host interaction, host seeking could be a powerful target for preventative intervention. However, host-seeking behavior remains poorly understood. Here we review what is currently known about the host-seeking behaviors of different parasitic nematodes, including insect-parasitic nematodes, mammalian-parasitic nematodes, and plant-parasitic nematodes. We also discuss the neural bases of these behaviors. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. root nematode control and crop yield

    African Journals Online (AJOL)

    SARAH

    2016-05-31

    May 31, 2016 ... The relationship between cost and benefit of the nematicide applications was also estimated. ... based on nematode threshold (100 nematodes per g of fresh root) which resulted in two applications; ..... France. Araya M, 2004. Situación actual del manejo de nematodos en banano (Musa AAA) y plátano.

  15. Benthic freshwater nematode community dynamics under conditions ...

    African Journals Online (AJOL)

    Studies of the influence of fish aquaculture on benthic freshwater nematode assemblages are scarce, but could provide a way of gauging environmental effects. The abundance and diversity of nematode assemblages in response to Oreochromis niloticus aquaculture were investigated in Kafr El-Sheikh Governorate, Egypt, ...

  16. How do humans affect wildlife nematodes?

    Science.gov (United States)

    Weinstein, Sara B.; Lafferty, Kevin D.

    2015-01-01

    Human actions can affect wildlife and their nematode parasites. Species introductions and human-facilitated range expansions can create new host–parasite interactions. Novel hosts can introduce parasites and have the potential to both amplify and dilute nematode transmission. Furthermore, humans can alter existing nematode dynamics by changing host densities and the abiotic conditions that affect larval parasite survival. Human impacts on wildlife might impair parasites by reducing the abundance of their hosts; however, domestic animal production and complex life cycles can maintain transmission even when wildlife becomes rare. Although wildlife nematodes have many possible responses to human actions, understanding host and parasite natural history, and the mechanisms behind the changing disease dynamics might improve disease control in the few cases where nematode parasitism impacts wildlife.

  17. Changes in plant species richness induce functional shifts in soil nematode communities in experimental grassland.

    Directory of Open Access Journals (Sweden)

    Nico Eisenhauer

    Full Text Available Changes in plant diversity may induce distinct changes in soil food web structure and accompanying soil feedbacks to plants. However, knowledge of the long-term consequences of plant community simplification for soil animal food webs and functioning is scarce. Nematodes, the most abundant and diverse soil Metazoa, represent the complexity of soil food webs as they comprise all major trophic groups and allow calculation of a number of functional indices.We studied the functional composition of nematode communities three and five years after establishment of a grassland plant diversity experiment (Jena Experiment. In response to plant community simplification common nematode species disappeared and pronounced functional shifts in community structure occurred. The relevance of the fungal energy channel was higher in spring 2007 than in autumn 2005, particularly in species-rich plant assemblages. This resulted in a significant positive relationship between plant species richness and the ratio of fungal-to-bacterial feeders. Moreover, the density of predators increased significantly with plant diversity after five years, pointing to increased soil food web complexity in species-rich plant assemblages. Remarkably, in complex plant communities the nematode community shifted in favour of microbivores and predators, thereby reducing the relative abundance of plant feeders after five years.The results suggest that species-poor plant assemblages may suffer from nematode communities detrimental to plants, whereas species-rich plant assemblages support a higher proportion of microbivorous nematodes stimulating nutrient cycling and hence plant performance; i.e. effects of nematodes on plants may switch from negative to positive. Overall, food web complexity is likely to decrease in response to plant community simplification and results of this study suggest that this results mainly from the loss of common species which likely alter plant-nematode interactions.

  18. Vaccinia virus, herpes simplex virus, and carcinogens induce DNA amplification in a human cell line and support replication of a helpervirus dependent parvovirus

    International Nuclear Information System (INIS)

    Schlehofer, J.R.; Ehrbar, M.; zur Hausen, H.

    1986-01-01

    The SV40-transformed human kidney cell line, NB-E, amplifies integrated as well as episomal SV40 DNA upon treatment with chemical (DMBA) or physical (uv irradiation) carcinogens (initiators) as well as after infection with herpes simplex virus (HSV) type 1 or with vaccinia virus. In addition it is shown that vaccinia virus induces SV40 DNA amplification also in the SV40-transformed Chinese hamster embryo cell line, CO631. These findings demonstrate that human cells similar to Chinese hamster cells amplify integrated DNA sequences after treatment with carcinogens or infection with specific viruses. Furthermore, a poxvirus--vaccinia virus--similar to herpes group viruses induces DNA amplification. As reported for other systems, the vaccinia virus-induced DNA amplification in NB-E cells is inhibited by coinfection with adeno-associated virus (AAV) type 5. This is in line with previous studies on inhibition of carcinogen- or HSV-induced DNA amplification in CO631 cells. The experiments also demonstrate that vaccinia virus, in addition to herpes and adenoviruses acts as a helper virus for replication and structural antigen synthesis of AAV-5 in NB-E cells

  19. Interspecific nematode signals regulate dispersal behavior.

    Directory of Open Access Journals (Sweden)

    Fatma Kaplan

    Full Text Available Dispersal is an important nematode behavior. Upon crowding or food depletion, the free living bacteriovorus nematode Caenorhabditis elegans produces stress resistant dispersal larvae, called dauer, which are analogous to second stage juveniles (J2 of plant parasitic Meloidogyne spp. and infective juveniles (IJs of entomopathogenic nematodes (EPN, e.g., Steinernema feltiae. Regulation of dispersal behavior has not been thoroughly investigated for C. elegans or any other nematode species. Based on the fact that ascarosides regulate entry in dauer stage as well as multiple behaviors in C. elegans adults including mating, avoidance and aggregation, we hypothesized that ascarosides might also be involved in regulation of dispersal behavior in C. elegans and for other nematodes such as IJ of phylogenetically related EPNs.Liquid chromatography-mass spectrometry analysis of C. elegans dauer conditioned media, which shows strong dispersing activity, revealed four known ascarosides (ascr#2, ascr#3, ascr#8, icas#9. A synthetic blend of these ascarosides at physiologically relevant concentrations dispersed C. elegans dauer in the presence of food and also caused dispersion of IJs of S. feltiae and J2s of plant parasitic Meloidogyne spp. Assay guided fractionation revealed structural analogs as major active components of the S. feltiae (ascr#9 and C. elegans (ascr#2 dispersal blends. Further analysis revealed ascr#9 in all Steinernema spp. and Heterorhabditis spp. infected insect host cadavers.Ascaroside blends represent evolutionarily conserved, fundamentally important communication systems for nematodes from diverse habitats, and thus may provide sustainable means for control of parasitic nematodes.

  20. Nematode communities in contaminated river sediments

    International Nuclear Information System (INIS)

    Heininger, Peter; Hoess, Sebastian; Claus, Evelyn; Pelzer, Juergen; Traunspurger, Walter

    2007-01-01

    Nematode communities of eight sites from three river catchments were investigated in terms of the genera composition, feeding types, and life-history strategists. The sampling sites showed a gradient of anthropogenic contamination with heavy metals and organic pollutants being important factors in differentiating the sites. Nematode community structure was related to sediment pollution and the hydro-morphological structure of the sampling sites. Heavily contaminated sites were characterized by communities with high relative abundances of omnivorous and predacious nematodes (Tobrilus, c-p 3; Mononchus, c-p 4), while sites with low to medium contamination were dominated by bacterivorous nematodes (Monhystera, Daptonema; c-p 2) or suction feeders (Dorylaimus, c-p 4). The relatively high Maturity Index values in the heavily polluted sites were surprising. Nematodes turned out to be a suitable organism group for monitoring sediment quality, with generic composition being the most accurate indicator for assessing differences in nematode community structure. - Nematode community structure of river sediments is related to pollution and site structure

  1. Nematode communities in contaminated river sediments

    Energy Technology Data Exchange (ETDEWEB)

    Heininger, Peter [Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56068 Koblenz (Germany); Hoess, Sebastian [Ecossa - Ecological Sediment and Soil Assessment, Thierschstr. 43, 80538 Munich (Germany); Claus, Evelyn [Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56068 Koblenz (Germany); Pelzer, Juergen [Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56068 Koblenz (Germany); Traunspurger, Walter [University of Bielefeld, Department of Animal Ecology, Morgenbreede 45, 33615 Bielefeld (Germany)]. E-mail: traunspurger@uni-bielefeld.de

    2007-03-15

    Nematode communities of eight sites from three river catchments were investigated in terms of the genera composition, feeding types, and life-history strategists. The sampling sites showed a gradient of anthropogenic contamination with heavy metals and organic pollutants being important factors in differentiating the sites. Nematode community structure was related to sediment pollution and the hydro-morphological structure of the sampling sites. Heavily contaminated sites were characterized by communities with high relative abundances of omnivorous and predacious nematodes (Tobrilus, c-p 3; Mononchus, c-p 4), while sites with low to medium contamination were dominated by bacterivorous nematodes (Monhystera, Daptonema; c-p 2) or suction feeders (Dorylaimus, c-p 4). The relatively high Maturity Index values in the heavily polluted sites were surprising. Nematodes turned out to be a suitable organism group for monitoring sediment quality, with generic composition being the most accurate indicator for assessing differences in nematode community structure. - Nematode community structure of river sediments is related to pollution and site structure.

  2. DNA replication and cancer

    DEFF Research Database (Denmark)

    Boyer, Anne-Sophie; Walter, David; Sørensen, Claus Storgaard

    2016-01-01

    A dividing cell has to duplicate its DNA precisely once during the cell cycle to preserve genome integrity avoiding the accumulation of genetic aberrations that promote diseases such as cancer. A large number of endogenous impacts can challenge DNA replication and cells harbor a battery of pathways...... causing DNA replication stress and genome instability. Further, we describe cellular and systemic responses to these insults with a focus on DNA replication restart pathways. Finally, we discuss the therapeutic potential of exploiting intrinsic replicative stress in cancer cells for targeted therapy....

  3. A Simple Method to Measure Nematodes' Propulsive Thrust and the Nematode Ratchet.

    Science.gov (United States)

    Bau, Haim; Yuan, Jinzhou; Raizen, David

    2015-11-01

    Since the propulsive thrust of micro organisms provides a more sensitive indicator of the animal's health and response to drugs than motility, a simple, high throughput, direct measurement of the thrust is desired. Taking advantage of the nematode C. elegans being heavier than water, we devised a simple method to determine the propulsive thrust of the animals by monitoring their velocity when swimming along an inclined plane. We find that the swimming velocity is a linear function of the sin of the inclination angle. This method allows us to determine, among other things, the animas' propulsive thrust as a function of genotype, drugs, and age. Furthermore, taking advantage of the animals' inability to swim over a stiff incline, we constructed a sawteeth ratchet-like track that restricts the animals to swim in a predetermined direction. This research was supported, in part, by NIH NIA Grant 5R03AG042690-02.

  4. IMPORTANT NEMATODE INFECTIONS IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Sri Oemijati

    2012-09-01

    Full Text Available At least 13 species of intestinal nematodes and 4 species of blood and tissue nematodes have been reported infecting man in Indonesia. Five species of intestinal nematodes are very common and highly prevalent, especially in the rural areas and slums of the big cities. Those species are Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale, Trichuris trichiura and Oxyuris vermicularis, while Strongyloides stercoralis is disappearing. The prevalence of the soil transmitted helminths differs from place to place, depending on many factors such as the type of soil, human behaviour etc. Three species of lymph dwelling filarial worms are known to be endemic, the urban Wuchereria bancrofti is low endemic in Jakarta and a few other cities along the north coast of Java, with Culex incriminated as vector, high endemicity is found in Irian Jaya, where Anopheline mosquitoes act as vectors. Brugia malayi is widely distributed and is still highly endemic in many areas. The zoonotic type is mainly endemic in swampy areas, and has many species of Mansonia mosquitoes as vectors. B.timori so far has been found only in the south eastern part of the archipelago and has Anopheles barbirostris as vector. Human infections with animal parasites have been diagnosed properly only when adult stages were found either in autopsies or removed tissues. Cases of infections with A. caninum, A.braziliense, A.ceylanicum, Trichostrongylus colubriformis, T.axei and Oesophagostomum apiostomum have been desribed from autopsies, while infections with Gnathostoma spiningerum have been reported from removed tissues. Infections with the larval stages such as VLM, eosinophylic meningitis, occult filanasis and other could only be suspected, since the diagnosis was extremely difficult and based on the finding and identification of the parasite. Many cases of creeping eruption which might be caused by the larval stages of A.caninum and A.braziliense and Strongyloides stercoralis

  5. Replicating animal mitochondrial DNA

    Directory of Open Access Journals (Sweden)

    Emily A. McKinney

    2013-01-01

    Full Text Available The field of mitochondrial DNA (mtDNA replication has been experiencing incredible progress in recent years, and yet little is certain about the mechanism(s used by animal cells to replicate this plasmid-like genome. The long-standing strand-displacement model of mammalian mtDNA replication (for which single-stranded DNA intermediates are a hallmark has been intensively challenged by a new set of data, which suggests that replication proceeds via coupled leading-and lagging-strand synthesis (resembling bacterial genome replication and/or via long stretches of RNA intermediates laid on the mtDNA lagging-strand (the so called RITOLS. The set of proteins required for mtDNA replication is small and includes the catalytic and accessory subunits of DNA polymerase y, the mtDNA helicase Twinkle, the mitochondrial single-stranded DNA-binding protein, and the mitochondrial RNA polymerase (which most likely functions as the mtDNA primase. Mutations in the genes coding for the first three proteins are associated with human diseases and premature aging, justifying the research interest in the genetic, biochemical and structural properties of the mtDNA replication machinery. Here we summarize these properties and discuss the current models of mtDNA replication in animal cells.

  6. Who Needs Replication?

    Science.gov (United States)

    Porte, Graeme

    2013-01-01

    In this paper, the editor of a recent Cambridge University Press book on research methods discusses replicating previous key studies to throw more light on their reliability and generalizability. Replication research is presented as an accepted method of validating previous research by providing comparability between the original and replicated…

  7. Parasitic Nematode Interactions with Mammals and Plants

    NARCIS (Netherlands)

    Jasmer, D.P.; Goverse, A.; Smant, G.

    2003-01-01

    Parasitic nematodes that infect humans, animals, and plants cause serious diseases that are deleterious to human health and agricultural productivity. Chemical and biological control methods have reduced the impact of these parasites. However, surviving environmental stages lead to persistent

  8. Genome Evolution of Plant-Parasitic Nematodes.

    Science.gov (United States)

    Kikuchi, Taisei; Eves-van den Akker, Sebastian; Jones, John T

    2017-08-04

    Plant parasitism has evolved independently on at least four separate occasions in the phylum Nematoda. The application of next-generation sequencing (NGS) to plant-parasitic nematodes has allowed a wide range of genome- or transcriptome-level comparisons, and these have identified genome adaptations that enable parasitism of plants. Current genome data suggest that horizontal gene transfer, gene family expansions, evolution of new genes that mediate interactions with the host, and parasitism-specific gene regulation are important adaptations that allow nematodes to parasitize plants. Sequencing of a larger number of nematode genomes, including plant parasites that show different modes of parasitism or that have evolved in currently unsampled clades, and using free-living taxa as comparators would allow more detailed analysis and a better understanding of the organization of key genes within the genomes. This would facilitate a more complete understanding of the way in which parasitism has shaped the genomes of plant-parasitic nematodes.

  9. WormBase: Annotating many nematode genomes.

    Science.gov (United States)

    Howe, Kevin; Davis, Paul; Paulini, Michael; Tuli, Mary Ann; Williams, Gary; Yook, Karen; Durbin, Richard; Kersey, Paul; Sternberg, Paul W

    2012-01-01

    WormBase (www.wormbase.org) has been serving the scientific community for over 11 years as the central repository for genomic and genetic information for the soil nematode Caenorhabditis elegans. The resource has evolved from its beginnings as a database housing the genomic sequence and genetic and physical maps of a single species, and now represents the breadth and diversity of nematode research, currently serving genome sequence and annotation for around 20 nematodes. In this article, we focus on WormBase's role of genome sequence annotation, describing how we annotate and integrate data from a growing collection of nematode species and strains. We also review our approaches to sequence curation, and discuss the impact on annotation quality of large functional genomics projects such as modENCODE.

  10. Manual of Cupule Replication Technology

    Directory of Open Access Journals (Sweden)

    Giriraj Kumar

    2015-09-01

    Full Text Available Throughout the world, iconic rock art is preceded by non-iconic rock art. Cupules (manmade, roughly semi-hemispherical depressions on rocks form the major bulk of the early non-iconic rock art globally. The antiquity of cupules extends back to the Lower Paleolithic in Asia and Africa, hundreds of thousand years ago. When one observes these cupules, the inquisitive mind poses so many questions with regard to understanding their technology, reasons for selecting the site, which rocks were used to make the hammer stones used, the skill and cognitive abilities employed to create the different types of cupules, the objective of their creation, their age, and so on. Replication of the cupules can provide satisfactory answers to some of these questions. Comparison of the hammer stones and cupules produced by the replication process with those obtained from excavation can provide support to observations. This paper presents a manual of cupule replication technology based on our experience of cupule replication on hard quartzite rock near Daraki-Chattan in the Chambal Basin, India.

  11. Fungi associated with free-living soil nematodes in Turkey

    Directory of Open Access Journals (Sweden)

    Karabörklü Salih

    2015-01-01

    Full Text Available Free-living soil nematodes have successfully adapted world-wide to nearly all soil types from the highest to the lowest of elevations. In the current study, nematodes were isolated from soil samples and fungi associated with these free-living soil nematodes were determined. Large subunit (LSU rDNAs of nematode-associated fungi were amplified and sequenced to construct phylogenetic trees. Nematode-associated fungi were observed in six nematode strains belonging to Acrobeloides, Steinernema and Cephalobus genera in different habitats. Malassezia and Cladosporium fungal strains indicated an association with Acrobeloides and Cephalobus nematodes, while Alternaria strains demonstrated an association with the Steinernema strain. Interactions between fungi and free-living nematodes in soil are discussed. We suggest that nematodes act as vectors for fungi.

  12. Conserving and enhancing biological control of nematodes.

    Science.gov (United States)

    Timper, Patricia

    2014-06-01

    Conservation biological control is the modification of the environment or existing practices to protect and enhance antagonistic organisms to reduce damage from pests. This approach to biological control has received insufficient attention compared with inundative applications of microbial antagonists to control nematodes. This review provides examples of how production practices can enhance or diminish biological control of plant-parasitic nematodes and other soilborne pests. Antagonists of nematodes can be enhanced by providing supplementary food sources such as occurs when organic amendments are applied to soil. However, some organic amendments (e.g., manures and plants containing allelopathic compounds) can also be detrimental to nematode antagonists. Plant species and genotype can strongly influence the outcome of biological control. For instance, the susceptibility of the plant to the nematode can determine the effectiveness of control; good hosts will require greater levels of suppression than poor hosts. Plant genotype can also influence the degree of rhizosphere colonization and antibiotic production by antagonists, as well the expression of induced resistance by plants. Production practices such as crop rotation, fallow periods, tillage, and pesticide applications can directly disrupt populations of antagonistic organisms. These practices can also indirectly affect antagonists by reducing their primary nematode host. One of the challenges of conservation biological control is that practices intended to protect or enhance suppression of nematodes may not be effective in all field sites because they are dependent on indigenous antagonists. Ultimately, indicators will need to be identified, such as the presence of particular antagonists, which can guide decisions on where it is practical to use conservation biological control. Antagonists can also be applied to field sites in conjunction with conservation practices to improve the consistency, efficacy, and

  13. Nematode parasites of animals are more prone to develop xenobiotic resistance than nematode parasites of plants

    Directory of Open Access Journals (Sweden)

    Silvestre A.

    2004-06-01

    Full Text Available In this paper, we concentrate on a comparison of plant and animal-parasitic nematodes, to gain insight into the factors that influence the acquisition of the drug resistance by nematodes. Comparing nematode parasite of domestic animals and cultivated plants, it appears that drug resistance threatens only domestic animal production. Does the paucity of report on nematicide field resistance reflect reality or, is nematicide resistance bypassed by other management practices, specific to cultivated plants (i.e. agricultural control ? First, it seems that selection pressure by treatments in plants is not as efficient as selection pressure in ruminants. Agronomic practices (i.e. sanitation, early planting, usage of nematodes resistant cultivar and crop rotation are frequently used to control parasitic-plant nematodes. Although the efficiency of such measures is generally moderate to high, integrated approaches are developing successfully in parasitic-plant nematode models. Secondly, the majority of anthelmintic resistance cases recorded in animal-parasitic nematodes concern drug families that are not used in plant-parasitic nematodes control (i.e. benzimidazoles, avermectines and levamisole. Thirdly, particular life traits of parasitic-plant nematodes (low to moderate fecundity and reproductive strategy are expected to reduce probability of appearance and transmission of drug resistance genes. It has been demonstrated that, for a large number of nematodes such as Meloidogyne spp., the mode of reproduction by mitotic parthenogenesis reduced genetic diversity of populations which may prevent a rapid drug resistance development. In conclusion, anthelmintic resistance develops in nematode parasite of animals as a consequence of an efficient selection pressure. Early detection of anthelmintic resistance is then crucial : it is not possible to avoid it, but only to delay its development in farm animal industry.

  14. The effects of repeated applications of the molluscicide metaldehyde and the biocontrol nematode Phasmarhabditis hermaphrodita on molluscs, earthworms, nematodes, acarids and collembolans: a two-year study in north-west Spain.

    Science.gov (United States)

    Iglesias, Javier; Castillejo, José; Castro, Ramón

    2003-11-01

    Over two years, six consecutive field experiments were done in which the chemical molluscicide metaldehyde and the nematode biocontrol agent Phasmarhabditis hermaphrodita (Schneider) were applied at the standard field rates to replicated mini-plots successively planted with lettuce, Brussels sprouts, leaf beet and cabbage, to compare the effectiveness of different treatments in reducing slug damage to the crops. Soil samples from each plot were taken prior to the start of the experiments, and then monthly, to assess the populations of slugs, snails, earthworms, nematodes, acarids and collembolans. The experiments were done on the same site and each plot received the same treatment in the six experiments. The six treatments were: (1) untreated controls, (2) metaldehyde pellets, (3 and 4) nematodes applied to the planted area 3 days prior to planting without or with previous application of cow manure slurry, (5) nematodes applied to the area surrounding the planted area 3 days prior to planting, and (6) nematodes applied to the planted area once (only in the first of the six consecutive experiments). Only the metaldehyde treatment and the nematodes applied to the planted area at the beginning of each experiment without previous application of manure significantly reduced slug damage to the plants, and only metaldehyde reduced the number of slugs contaminating the harvested plants. The numbers of slugs, snails and earthworms in soil samples were compared among the six treatments tested: with respect to the untreated controls, the numbers of Deroceras reticulatum (Müller) were significantly affected only in the metaldehyde plots, and the numbers of Arion ater L only in the plots treated with nematodes applied to the planted area 3 days prior to planting without previous application of manure; numbers of snails (Ponentina ponentina (Morelet) and Oxychilus helveticus (Blum)) were not affected by the treatment. The total numbers of all earthworm species and of Lumbricus

  15. Diversity of bacteria carried by pinewood nematode in USA and phylogenetic comparison with isolates from other countries.

    Directory of Open Access Journals (Sweden)

    Diogo Neves Proença

    Full Text Available Pine wilt disease (PWD is native to North America and has spread to Asia and Europe. Lately, mutualistic relationship has been suggested between the pinewood nematode (PWN, Bursaphelenchus xylophilus the causal nematode agent of PWD, and bacteria. In countries where PWN occurs, nematodes from diseased trees were reported to carry bacteria from several genera. However no data exists for the United States. The objective of this study was to evaluate the diversity of the bacterial community carried by B. xylophilus, isolated from different Pinus spp. with PWD in Nebraska, United States. The bacteria carried by PWN belonged to Gammaproteobacteria (79.9%, Betaproteobacteria (11.7%, Bacilli (5.0%, Alphaproteobacteria (1.7% and Flavobacteriia (1.7%. Strains from the genera Chryseobacterium and Pigmentiphaga were found associated with the nematode for the first time. These results were compared to results from similar studies conducted from other countries of three continents in order to assess the diversity of bacteria with associated with PWN. The isolates from the United States, Portugal and China belonged to 25 different genera and only strains from the genus Pseudomonas were found in nematodes from all countries. The strains from China were closely related to P. fluorescens and the strains isolated from Portugal and USA were phylogenetically related to P. mohnii and P. lutea. Nematodes from the different countries are associated with bacteria of different species, not supporting a relationship between PWN with a particular bacterial species. Moreover, the diversity of the bacteria carried by the pinewood nematode seems to be related to the geographic area and the Pinus species. The roles these bacteria play within the pine trees or when associated with the nematodes, might be independent of the presence of the nematode in the tree and only related on the bacteria's relationship with the tree.

  16. Drechslerella stenobrocha genome illustrates the mechanism of constricting rings and the origin of nematode predation in fungi

    Science.gov (United States)

    2014-01-01

    Background Nematode-trapping fungi are a unique group of organisms that can capture nematodes using sophisticated trapping structures. The genome of Drechslerella stenobrocha, a constricting-ring-forming fungus, has been sequenced and reported, and provided new insights into the evolutionary origins of nematode predation in fungi, the trapping mechanisms, and the dual lifestyles of saprophagy and predation. Results The genome of the fungus Drechslerella stenobrocha, which mechanically traps nematodes using a constricting ring, was sequenced. The genome was 29.02 Mb in size and was found rare instances of transposons and repeat induced point mutations, than that of Arthrobotrys oligospora. The functional proteins involved in nematode-infection, such as chitinases, subtilisins, and adhesive proteins, underwent a significant expansion in the A. oligospora genome, while there were fewer lectin genes that mediate fungus-nematode recognition in the D. stenobrocha genome. The carbohydrate-degrading enzyme catalogs in both species were similar to those of efficient cellulolytic fungi, suggesting a saprophytic origin of nematode-trapping fungi. In D. stenobrocha, the down-regulation of saprophytic enzyme genes and the up-regulation of infection-related genes during the capture of nematodes indicated a transition between dual life strategies of saprophagy and predation. The transcriptional profiles also indicated that trap formation was related to the protein kinase C (PKC) signal pathway and regulated by Zn(2)–C6 type transcription factors. Conclusions The genome of D. stenobrocha provides support for the hypothesis that nematode trapping fungi evolved from saprophytic fungi in a high carbon and low nitrogen environment. It reveals the transition between saprophagy and predation of these fungi and also proves new insights into the mechanisms of mechanical trapping. PMID:24507587

  17. Antagonistic Activities of Streptomyces against Root Knot Nematode of Kiwifruit

    Directory of Open Access Journals (Sweden)

    S. Bashiri

    2016-02-01

    into counting Petri plate and examined under a stereomicroscope. Nematode larvae were identified to generic level and were counted. Evaluation of Actinomycetes isolates against root-knot nematodes in vitro performed according to Sun et al. Seedlings (Six-month-old of kiwifruit (Actinidia deliciosa were sown in 30 cm3 pots containing autoclaved sandy loam soil (1:1. Pots were divided into three groups by three replicates. Bioagents were individually incorporated into the soil at a dose rate of 10 cm3 (Heavy cell suspension of all isolates was prepared at rate 105 spores ml-1 were added to the soil. After seven days, (when bacterial cells reach its maximum growth peak plants were inoculated with 2000 freshly hatched second stage juveniles(J2 of Meloidogyne spp. Pots were fertilized with recommended dose and kept at 25ºC ± 3ºC in complete randomized design. After two months plants were uprooted then galls and egg masses were counted and their indices were recorded according to Sharma et al. Fresh weight of roots was also registered. Treatments means were compared by the Duncan Multiple Range Test at 0.05 level of probability. The growth responses of kiwifruit (roots weight and number of galls and egg mass were also recorded. Statistical analyses were achieved using SAS. Results and Discussion: Among 25 isolates identified as Streptomyces genus, 9 Actinomycetes isolates showed the antagonistic potential in vitro and reduced the rate of egg hatching in seven days and larval mortality in four days. Streptomyces sp3. Streptomyces sp4., Streptomyces sp5., Streptomyces sp9. And Streptomyces sp12. were able to reduce egg hatching 16.29%, 19.99%, 27.11%, 20.22% and 18.41% and increased the percentage of larval mortality 45%, 33.3%, 37.53%,35.01% and 37.50%, respectively. They showed the greatest effect and selected for evaluating in greenhouse condition. In addition, Streptomyces sp9.and Streptomyces sp4. reduced galls by 65.35% and 64.56% compared with the phenamiphus 57

  18. Sterol Binding by the Tombusviral Replication Proteins Is Essential for Replication in Yeast and Plants.

    Science.gov (United States)

    Xu, Kai; Nagy, Peter D

    2017-04-01

    Membranous structures derived from various organelles are important for replication of plus-stranded RNA viruses. Although the important roles of co-opted host proteins in RNA virus replication have been appreciated for a decade, the equally important functions of cellular lipids in virus replication have been gaining full attention only recently. Previous work with Tomato bushy stunt tombusvirus (TBSV) in model host yeast has revealed essential roles for phosphatidylethanolamine and sterols in viral replication. To further our understanding of the role of sterols in tombusvirus replication, in this work we showed that the TBSV p33 and p92 replication proteins could bind to sterols in vitro The sterol binding by p33 is supported by cholesterol recognition/interaction amino acid consensus (CRAC) and CARC-like sequences within the two transmembrane domains of p33. Mutagenesis of the critical Y amino acids within the CRAC and CARC sequences blocked TBSV replication in yeast and plant cells. We also showed the enrichment of sterols in the detergent-resistant membrane (DRM) fractions obtained from yeast and plant cells replicating TBSV. The DRMs could support viral RNA synthesis on both the endogenous and exogenous templates. A lipidomic approach showed the lack of enhancement of sterol levels in yeast and plant cells replicating TBSV. The data support the notion that the TBSV replication proteins are associated with sterol-rich detergent-resistant membranes in yeast and plant cells. Together, the results obtained in this study and the previously published results support the local enrichment of sterols around the viral replication proteins that is critical for TBSV replication. IMPORTANCE One intriguing aspect of viral infections is their dependence on efficient subcellular assembly platforms serving replication, virion assembly, or virus egress via budding out of infected cells. These assembly platforms might involve sterol-rich membrane microdomains, which are

  19. Molecular mechanisms of nematode-nematophagous microbe interactions: basis for biological control of plant-parasitic nematodes.

    Science.gov (United States)

    Li, Juan; Zou, Chenggang; Xu, Jianping; Ji, Xinglai; Niu, Xuemei; Yang, Jinkui; Huang, Xiaowei; Zhang, Ke-Qin

    2015-01-01

    Plant-parasitic nematodes cause significant damage to a broad range of vegetables and agricultural crops throughout the world. As the natural enemies of nematodes, nematophagous microorganisms offer a promising approach to control the nematode pests. Some of these microorganisms produce traps to capture and kill the worms from the outside. Others act as internal parasites to produce toxins and virulence factors to kill the nematodes from within. Understanding the molecular basis of microbe-nematode interactions provides crucial insights for developing effective biological control agents against plant-parasitic nematodes. Here, we review recent advances in our understanding of the interactions between nematodes and nematophagous microorganisms, with a focus on the molecular mechanisms by which nematophagous microorganisms infect nematodes and on the nematode defense against pathogenic attacks. We conclude by discussing several key areas for future research and development, including potential approaches to apply our recent understandings to develop effective biocontrol strategies.

  20. Soybean cyst nematode culture collections and field populations from North Carolina and Missouri reveal high incidences of infection by viruses.

    Science.gov (United States)

    Ruark, Casey L; Koenning, Stephen R; Davis, Eric L; Opperman, Charles H; Lommel, Steven A; Mitchum, Melissa G; Sit, Tim L

    2017-01-01

    Five viruses were previously discovered infecting soybean cyst nematodes (SCN; Heterodera glycines) from greenhouse cultures maintained in Illinois. In this study, the five viruses [ScNV, ScPV, ScRV, ScTV, and SbCNV-5] were detected within SCN greenhouse and field populations from North Carolina (NC) and Missouri (MO). The prevalence and titers of viruses in SCN from 43 greenhouse cultures and 25 field populations were analyzed using qRT-PCR. Viral titers within SCN greenhouse cultures were similar throughout juvenile development, and the presence of viral anti-genomic RNAs within egg, second-stage juvenile (J2), and pooled J3 and J4 stages suggests active viral replication within the nematode. Viruses were found at similar or lower levels within field populations of SCN compared with greenhouse cultures of North Carolina populations. Five greenhouse cultures harbored all five known viruses whereas in most populations a mixture of fewer viruses was detected. In contrast, three greenhouse cultures of similar descent to one another did not possess any detectable viruses and primarily differed in location of the cultures (NC versus MO). Several of these SCN viruses were also detected in Heterodera trifolii (clover cyst) and Heterodera schachtii (beet cyst), but not the other cyst, root-knot, or reniform nematode species tested. Viruses were not detected within soybean host plant tissue. If nematode infection with viruses is truly more common than first considered, the potential influence on nematode biology, pathogenicity, ecology, and control warrants continued investigation.

  1. Laying a Solid Foundation: Strategies for Effective Program Replication

    Science.gov (United States)

    Summerville, Geri

    2009-01-01

    The replication of proven social programs is a cost-effective and efficient way to achieve large-scale, positive social change. Yet there has been little guidance available about how to approach program replication and limited development of systems--at local, state or federal levels--to support replication efforts. "Laying a Solid Foundation:…

  2. Evaluation of the Tolerance of Some Citrus Rootstocks to Citrus Nematode in Greenhouse (Tylenchulus semipenetrans

    Directory of Open Access Journals (Sweden)

    Y. Mohammad Alian

    2018-02-01

    Full Text Available Introduction: Citrus nematode is one of the most important damaging nematodes of citrus trees, spreading widely in most areas under citrus planting causing dieback, the gradual decline of trees and crop decrease in citrus orchards. Eighty citrus cultivars and species are sensitive to this nematode. From other nematode hosts, we can refer to olive, fig, medlar, persimmon, pear and grapevine. Surveys Full filled in Mazandaran province is indicative of the widespread of this nematode in citrus horticulture and the level of infection in some samples is so high, thus it is necessary to use different ways of controlling this parasite. Materials and Methods: This research was carried out for 2 successive years and the reaction of sin citrus rootstocks including Citromelo, Poncirus, Sour Orange, Bakraee, Rough lemon and Off-type to citrus nematode under controlled conditions in the greenhouse was evaluated. Three months years old plants of this rootstock Were planted in completely random design with 5 replications in pots containing the population of 40 larvae per cubic centimeter of soil and after six months, the level of infection of roots was investigated and then the most tolerable rootstock for nematode was introduced on the basis of the least population of young females and adult females injected in one gram of root volume. Results and Discussion: Experiment results on the basis of LSD test in two successive years indicated that there is a meaningful statistical difference between Citrumelo and poncirus Poncirus with the least population of nematode of adult female on the root and other treatments the results show that sour orange and off-type rootstocks are the most sensitive to citrus nematode, poncirus Poncirus and Citrumelo are the most tolerable to nematode Bakraee and Rough lemon are in the biotype group with average tolerance (relatively sensitive to citrus nematode. Purpose of this research is to assess the sensitivity level of six citrus

  3. Registered Replication Report

    DEFF Research Database (Denmark)

    Bouwmeester, S.; Verkoeijen, P. P.J.L.; Aczel, B.

    2017-01-01

    and colleagues. The results of studies using time pressure have been mixed, with some replication attempts observing similar patterns (e.g., Rand et al., 2014) and others observing null effects (e.g., Tinghög et al., 2013; Verkoeijen & Bouwmeester, 2014). This Registered Replication Report (RRR) assessed...... the size and variability of the effect of time pressure on cooperative decisions by combining 21 separate, preregistered replications of the critical conditions from Study 7 of the original article (Rand et al., 2012). The primary planned analysis used data from all participants who were randomly assigned...

  4. Phloem development in nematode-induced feeding sites: The implications of auxin and cytokinin

    Directory of Open Access Journals (Sweden)

    Birgit eAbsmanner

    2013-07-01

    Full Text Available Sedentary plant parasitic nematodes such as root-knot nematodes and cyst nematodes induce giant cells or syncytia, respectively, in their host plant’s roots. These highly specialized structures serve as feeding sites from which exclusively the nematodes withdraw nutrients. While giant cells are symplastically isolated and obtain assimilates by transporter-mediated processes syncytia are massively connected to the phloem by plasmodesmata. To support the feeding sites and the nematode during their development, phloem is induced around syncytia and giant cells. In the case of syncytia the unloading phloem consists of sieve elements and companion cells and in the case of root knots it consists exclusively of sieve elements. We applied immunohistochemistry to identify the cells within the developing phloem that responded to auxin and cytokinin. Both feeding sites themselves did not respond to either hormone. We were able to show that in root knots an auxin response precedes the differentiation of these auxin responsive cells into phloem elements. This process appears to be independent of B-type Arabidopsis response regulators. Using additional markers for tissue identity we provide evidence that around giant cells protophloem is formed and proliferates dramatically. In contrast, the phloem around syncytia responded to both hormones. The presence of companion cells as well as hormone-responsive sieve elements suggests that metaphloem development occurs. The implication of auxin and cytokinin in the further development of the metaphloem is discussed.

  5. The replication recipe : What makes for a convincing replication?

    NARCIS (Netherlands)

    Brandt, M.J.; IJzerman, H.; Dijksterhuis, Ap; Farach, Frank J.; Geller, Jason; Giner-Sorolla, Roger; Grange, James A.; Perugini, Marco; Spies, Jeffrey R.; van 't Veer, Anna

    Psychological scientists have recently started to reconsider the importance of close replications in building a cumulative knowledge base; however, there is no consensus about what constitutes a convincing close replication study. To facilitate convincing close replication attempts we have developed

  6. The Replication Recipe: What makes for a convincing replication?

    NARCIS (Netherlands)

    Brandt, M.J.; IJzerman, H.; Dijksterhuis, A.J.; Farach, F.J.; Geller, J.; Giner-Sorolla, R.; Grange, J.A.; Perugini, M.; Spies, J.R.; Veer, A. van 't

    2014-01-01

    Psychological scientists have recently started to reconsider the importance of close replications in building a cumulative knowledge base; however, there is no consensus about what constitutes a convincing close replication study. To facilitate convincing close replication attempts we have developed

  7. Replicator dynamics in value chains

    DEFF Research Database (Denmark)

    Cantner, Uwe; Savin, Ivan; Vannuccini, Simone

    2016-01-01

    The pure model of replicator dynamics though providing important insights in the evolution of markets has not found much of empirical support. This paper extends the model to the case of firms vertically integrated in value chains. We show that i) by taking value chains into account, the replicator...... dynamics may revert its effect. In these regressive developments of market selection, firms with low fitness expand because of being integrated with highly fit partners, and the other way around; ii) allowing partner's switching within a value chain illustrates that periods of instability in the early...... stage of industry life-cycle may be the result of an 'optimization' of partners within a value chain providing a novel and simple explanation to the evidence discussed by Mazzucato (1998); iii) there are distinct differences in the contribution to market selection between the layers of a value chain...

  8. Computational Replication of the Primary Isotope Dependence of Secondary Kinetic Isotope Effects in Solution Hydride-Transfer Reactions: Supporting the Isotopically Different Tunneling Ready State Conformations.

    Science.gov (United States)

    Derakhshani-Molayousefi, Mortaza; Kashefolgheta, Sadra; Eilers, James E; Lu, Yun

    2016-06-30

    We recently reported a study of the steric effect on the 1° isotope dependence of 2° KIEs for several hydride-transfer reactions in solution (J. Am. Chem. Soc. 2015, 137, 6653). The unusual 2° KIEs decrease as the 1° isotope changes from H to D, and more in the sterically hindered systems. These were explained in terms of a more crowded tunneling ready state (TRS) conformation in D-tunneling, which has a shorter donor-acceptor distance (DAD) than in H-tunneling. To examine the isotopic DAD difference explanation, in this paper, following an activated motion-assisted H-tunneling model that requires a shorter DAD in a heavier isotope transfer process, we computed the 2° KIEs at various H/D positions at different DADs (2.9 Å to 3.5 Å) for the hydride-transfer reactions from 2-propanol to the xanthylium and thioxanthylium ions (Xn(+) and TXn(+)) and their 9-phenyl substituted derivatives (Ph(T)Xn(+)). The calculated 2° KIEs match the experiments and the calculated DAD effect on the 2° KIEs fits the observed 1° isotope effect on the 2° KIEs. These support the motion-assisted H-tunneling model and the isotopically different TRS conformations. Furthermore, it was found that the TRS of the sterically hindered Ph(T)Xn(+) system does not possess a longer DAD than that of the (T)Xn(+) system. This predicts a no larger 1° KIE in the former system than in the latter. The observed 1° KIE order is, however, contrary to the prediction. This implicates the stronger DAD-compression vibrations coupled to the bulky Ph(T)Xn(+) reaction coordinate.

  9. Cerebrospinal fluid HIV-1 RNA levels in asymptomatic patients with early stage chronic HIV-1 infection: support for the hypothesis of local virus replication.

    Science.gov (United States)

    García, F; Niebla, G; Romeu, J; Vidal, C; Plana, M; Ortega, M; Ruiz, L; Gallart, T; Clotet, B; Miró, J M; Pumarola, T; Gatell, J M

    1999-08-20

    To assess HIV-1 RNA levels in cerebrospinal fluid (CSF) and their potential correlation with plasma viral load and central nervous system (CNS) HIV-1 infection markers in stable asymptomatic patients with a CD4 T cell count >500x10(6) cells/l. Consecutive patients screened for two trials were eligible for lumbar puncture assessment. At day 0, simultaneous samples of CSF and plasma were obtained and levels of total proteins, albumin, IgG, antibodies against HIV-1 p24 antigen, HIV-1 RNA (using the polymerase chain technique) and white cells were measured. The integrity of the blood-brain barrier was preserved (albumin index > or =7) in 59 out of 70 patients (84%). Intrathecal production of antibodies against HIV-1 p24 antigen was demonstrated in 55 out of 70 individuals (78%). Viral load in CSF was significantly lower than plasma values (3.13+/-0.95 versus 4.53+/-0.53, P = 0.0001). HIV-1 RNA was not detected in CSF in only three of the 70 patients (4%). Overall, there was a significant correlation between plasma and CSF HIV-1 RNA levels (r = 0.43, P = 0.0001); however, in 29 patients (41%) there were significant differences (>1.5 log10 copies/ml) between the viral loads in plasma and CSF. In the multivariate analysis, a high level of protein and white cells in CSF, but not the HIV-1 RNA plasma level, were factors independently associated with a higher level of HIV-1 RNA in CSF (P = 0.0001). HIV-1 RNA can be detected almost always in CSF of asymptomatic patients in early stages of HIV-1 infection including those with a preserved integrity of the blood-brain barrier. The important discrepancies between plasma and CSF viral load, and the independent association between CSF abnormalities and CSF viral load, support the hypothesis of local production of HIV-1.

  10. Modeling DNA Replication.

    Science.gov (United States)

    Bennett, Joan

    1998-01-01

    Recommends the use of a model of DNA made out of Velcro to help students visualize the steps of DNA replication. Includes a materials list, construction directions, and details of the demonstration using the model parts. (DDR)

  11. Chromatin Immunoprecipitation of Replication Factors Moving with the Replication Fork

    OpenAIRE

    Rapp, Jordan B.; Ansbach, Alison B.; Noguchi, Chiaki; Noguchi, Eishi

    2009-01-01

    Replication of chromosomes involves a variety of replication proteins including DNA polymerases, DNA helicases, and other accessory factors. Many of these proteins are known to localize at replication forks and travel with them as components of the replisome complex. Other proteins do not move with replication forks but still play an essential role in DNA replication. Therefore, in order to understand the mechanisms of DNA replication and its controls, it is important to examine localization ...

  12. Investigation of Nematode Diversity using Scanning Electron Microscopy and Fluorescent Microscopy

    Science.gov (United States)

    Seacor, Taylor; Howell, Carina

    2013-03-01

    Nematode worms account for the vast majority of the animals in the biosphere. They are colossally important to global public health as parasites, and to agriculture both as pests and as beneficial inhabitants of healthy soil. Amphid neurons are the anterior chemosensory neurons in nematodes, mediating critical behaviors including chemotaxis and mating. We are examining the cellular morphology and external anatomy of amphid neurons, using fluorescence microscopy and scanning electron microscopy, respectively, of a wide range of soil nematodes isolated in the wild. We use both classical systematics (e.g. diagnostic keys) and molecular markers (e.g. ribosomal RNA) to classify these wild isolates. Our ultimate aim is to build a detailed anatomical database in order to dissect genetic pathways of neuronal development and function across phylogeny and ecology. Research supported by NSF grants 092304, 0806660, 1058829 and Lock Haven University FPDC grants

  13. Mind the gaps in research on the control of gastrointestinal nematodes of farmed ruminants and pigs

    DEFF Research Database (Denmark)

    Charlier, J; Thamsborg, S M; Bartley, D J

    2018-01-01

    , to support the development of roadmaps and strategic research agendas by governments, industry and policymakers. These priorities were derived from the DISCONTOOLS gap analysis for nematodes and follow-up discussions within the recently formed Livestock Helminth Research Alliance (LiHRA). In the face......Gastrointestinal (GI) nematode control has an important role to play in increasing livestock production from a limited natural resource base and to improve animal health and welfare. In this synthetic review, we identify key research priorities for GI nematode control in farmed ruminants and pigs......-use and farm husbandry changes. More emphasis needs to be placed on the upfront evaluation of the economic value of these innovations as well as the socio-psychological aspects to prioritize research and facilitate uptake of innovations in practice. Finally, targeted regulatory guidance is needed to create...

  14. Steinernema biddulphi n. sp., a new entomopathogenic nematode (Nematoda: Steinernematidae) from South Africa

    Czech Academy of Sciences Publication Activity Database

    Çimen, H.; Půža, Vladimír; Nermuť, Jiří; Hatting, J.; Ramakuwela, T.; Hazir, S.

    2016-01-01

    Roč. 48, č. 3 (2016), s. 148-158 ISSN 0022-300X R&D Projects: GA MŠk LH12105 Institutional support: RVO:60077344 Keywords : D2-D3 * entomopathogenic nematodes * ITS Subject RIV: EG - Zoology Impact factor: 1.087, year: 2016 http://journals.fcla.edu/jon/issue/view/4275

  15. Redescription of two species of cystidicolid nematodes (Spirurina: Cystidicolidae) from Notopterus notopterus (Osteichthyes) in Thailand

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Pachanawan, A.; Kamchoo, K.

    2016-01-01

    Roč. 61, č. 2 (2016), s. 278-290 ISSN 1230-2821 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:60077344 Keywords : Parasitic nematode * Pseudoproleptus * Spinitectus * morphology * taxonomy * freshwater fish * Oriental Region Subject RIV: EG - Zoology Impact factor: 1.160, year: 2016

  16. Soil nematodes in alpine meadows of the Tatra National Park (Slovak Republic)

    Czech Academy of Sciences Publication Activity Database

    Háněl, Ladislav

    2017-01-01

    Roč. 54, č. 1 (2017), s. 48-67 ISSN 0440-6605 R&D Projects: GA ČR(CZ) GA14-09231S Institutional support: RVO:60077344 Keywords : soil nematodes * diversity * maturity * soil food web * alpine meadow Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 0.472, year: 2016

  17. The significance of the tail projections in female entomopathogenic nematodes within the family Steinernematidae

    Czech Academy of Sciences Publication Activity Database

    Mráček, Zdeněk; Půža, Vladimír; Nermuť, Jiří

    2016-01-01

    Roč. 90, č. 2 (2016), s. 249-251 ISSN 0022-149X R&D Projects: GA MŠk LH12105 Institutional support: RVO:60077344 Keywords : Steinernematidae * nematodes * Steinernema arenarium Subject RIV: EG - Zoology Impact factor: 1.420, year: 2016

  18. Findings of entomopathogenic nematodes (Rhabditida, Steinernematidae) in nature reserves in Ukraine

    Czech Academy of Sciences Publication Activity Database

    Yakovlev, Ye. B.; Kharchenko, V. A.; Mráček, Zdeněk

    2014-01-01

    Roč. 48, č. 3 (2014), s. 203-210 ISSN 0084-5604 R&D Projects: GA MŠk LH12105 Institutional support: RVO:60077344 Keywords : entomopathogenic nematode Subject RIV: EH - Ecology, Behaviour http://www.degruyter.com/view/j/vzoo.2014.48.issue-3/vzoo-2014-0023/vzoo-2014-0023.xml

  19. Extended phenotype: nematodes turn ants into bird-dispersed fruits

    DEFF Research Database (Denmark)

    Hughes, D P; Kronauer, D J C; Boomsma, J J

    2008-01-01

    A recent study has discovered a novel extended phenotype of a nematode which alters its ant host to resemble ripe fruit. The infected ants are in turn eaten by frugivorous birds that disperse the nematode's eggs.......A recent study has discovered a novel extended phenotype of a nematode which alters its ant host to resemble ripe fruit. The infected ants are in turn eaten by frugivorous birds that disperse the nematode's eggs....

  20. Studies on Lasioseius scapulatus, a Mesostigmatid mite predaceous on nematodes

    OpenAIRE

    Imbriani, I.; Mankau, R.

    1983-01-01

    The life history and feeding habits of Lasioseius scapulatus, an ascid predator and potential biocontrol agent of nematodes, was examined. Reproduction was asexual, and the life cycle was 8-10 days at room temperature. Life history consisted of the egg, protonymph, deutonymph, and adult. Both nymphal stages and the adult captured and consumed nematodes. Two fungal genera and eight genera of nematodes were suitable food sources. Second-stage root-knot nematode juveniles were eaten, but eggs an...

  1. Biocontrol: The Potential of Entomophilic Nematodes in Insect Management

    OpenAIRE

    Webster, John M.

    1980-01-01

    A review of the development of entomophilic nematology and a commentary on the potential of entomophilic nematodes in controlling insect pests. The paper considers some of the major contributions to our knowledge of entomophilic nematology; factors involved in insect pest management and how they are applicable to the use of nematodes; nematodes which are most promising as biological control agents; and problems to be solved to facilitate the use of entomophilic nematodes in insect management.

  2. Parasitic nematode interactions with mammals and plants.

    Science.gov (United States)

    Jasmer, Douglas P; Goverse, Aska; Smant, Geert

    2003-01-01

    Parasitic nematodes that infect humans, animals, and plants cause serious diseases that are deleterious to human health and agricultural productivity. Chemical and biological control methods have reduced the impact of these parasites. However, surviving environmental stages lead to persistent reinfection of host species. In addition, development of resistance to nematicides and anthelmintics by these parasites and reduced availability of some nematicides, for environmental protection, pose significant obstacles for current and future prospects of effective parasite control. Due to marked differences in host species, research on animal and plant parasitic nematodes often proceeds independently. Despite the differences between animals and plants, basic cellular properties are shared among these host organisms. Some common properties may be important for mechanisms [homologous or convergent (homoplastic)] by which nematodes successfully infect these diverse hosts or by which animal and plant hosts resist infections by these pathogens. Here we compare host/parasite interactions between plant parasitic nematodes (PPN) and animal parasitic nematodes, with an emphasis on mammalian hosts (MPN). Similarities and differences are considered in the context of progress on molecular dissection of these interactions. A comprehensive coverage is not possible in the space allotted. Instead, an illustrative approach is used to establish examples that, it is hoped, exemplify the value of the comparative approach.

  3. Management of Root-Nematode (Meloidogyne SPP)

    International Nuclear Information System (INIS)

    Miano, D.W

    2002-01-01

    Greenhouse and field experiments were undertaken to determine the possibility of using soil amendments with different C:N levels or applied at different rates and times in the control of root-knot nematodes (Meloidogyne spp.)in tomato c.v Cal J.A naturally infested field was used while artificial inoculation was done in the greenhouse. Root galling was rated on a scale of 0-10, nematode population was estimated by counting second stage juveniles extracted from 200 cm 3 soil and fruit yields were recorded at the end of the season. Nematode population densities and galling indices were significantly (P< or=0.05) lower in amended soils compared to the control. Application of the amendments also resulted in significant (P< or=0.05) increase in yields. Chicken manure, compost manure, neem products and pig manure were were the most effective amendments. Fresh chicken manure had a more suppressive effect on nematode than when the manure was decomposed within or outside a nematode infested field. A general decrease in juvenile populations and galling was observed with increase of organic amendments applied

  4. A New Replication Norm for Psychology

    Directory of Open Access Journals (Sweden)

    Etienne P LeBel

    2015-10-01

    Full Text Available In recent years, there has been a growing concern regarding the replicability of findings in psychology, including a mounting number of prominent findings that have failed to replicate via high-powered independent replication attempts. In the face of this replicability “crisis of confidence”, several initiatives have been implemented to increase the reliability of empirical findings. In the current article, I propose a new replication norm that aims to further boost the dependability of findings in psychology. Paralleling the extant social norm that researchers should peer review about three times as many articles that they themselves publish per year, the new replication norm states that researchers should aim to independently replicate important findings in their own research areas in proportion to the number of original studies they themselves publish per year (e.g., a 4:1 original-to-replication studies ratio. I argue this simple approach could significantly advance our science by increasing the reliability and cumulative nature of our empirical knowledge base, accelerating our theoretical understanding of psychological phenomena, instilling a focus on quality rather than quantity, and by facilitating our transformation toward a research culture where executing and reporting independent direct replications is viewed as an ordinary part of the research process. To help promote the new norm, I delineate (1 how each of the major constituencies of the research process (i.e., funders, journals, professional societies, departments, and individual researchers can incentivize replications and promote the new norm and (2 any obstacles each constituency faces in supporting the new norm.

  5. The prevalence of gastrointestinal nematode infection and their ...

    African Journals Online (AJOL)

    GIN infection was associated with 1.4 litres per cow per day less milk and this ... Gastrointestinal nematode (GIN) infections in cattle are of considerable economic importance .... Table 2. Mean faecal egg counts of gastrointestinal nematodes and the 95% confidence ... 3.2 Gastrointestinal nematode species. The pooled ...

  6. Ecology of the Pinewood Nematode in Southern Pine Chip Piles

    Science.gov (United States)

    L. David Dwinell

    1986-01-01

    The optimum temperature range for pinewood nematodes in southern pine chips was 35 to 40° C. Nematode populations declined at temperatures of -20°C. at temperatures above 45°C. and in anaerobic environments. Wood moisture content and presence of bluestain fungus also influenced nematode populations.

  7. Microbial ecology and nematode control in natural ecosystems

    NARCIS (Netherlands)

    Costa, S.R.; Van der Putten, W.H.; Kerry, B.R.

    2011-01-01

    Plant-parasitic nematodes have traditionally been studied in agricultural systems, where they can be pests of importance on a wide range of crops. Nevertheless, nematode ecology in natural ecosystems is receiving increasing interest because of the role of nematodes in soil food webs, nutrient

  8. Nematode CLE signaling in Arabidopsis requires CLAVATA2 and CORYNE

    Science.gov (United States)

    Plant-parasitic cyst nematodes secrete CLAVATA3 (CLV3)/ESR(CLE)-like effector proteins. These proteins have been shown to act as ligand mimics of plant CLE peptides and are required for successful nematode infection; however, the receptors for nematode CLE-like peptides have not been identified. Her...

  9. Opportunity to use native nematodes for pest control

    Science.gov (United States)

    We have surveyed wild cranberry bogs in WI and found three isolates of native nematodes. We have been testing these nematodes as potential biological control agents in for cranberry insect pests including sparganothis fruitworm and flea beetle. The nematodes seem to be effective at finding and killi...

  10. Bacterial microbiome and nematode occurrence in different potato agricultural soils

    Science.gov (United States)

    Pratylenchus neglectus and Meloidogyne chitwoodi are the main plant-parasitic nematodes in potato crops of the San Luis Valley, Colorado. Bacterial microbiome (16S rRNA copies per gram of soil) and nematode communities (nematodes per 200 gr of soil) from five different potato farms were analyzed to ...

  11. 77 FR 22185 - Golden Nematode; Removal of Regulated Areas

    Science.gov (United States)

    2012-04-13

    ...-0036] Golden Nematode; Removal of Regulated Areas AGENCY: Animal and Plant Health Inspection Service..., without change, an interim rule that amended the golden nematode regulations by removing the townships of... that the fields in these two townships are free of golden nematode, and we determined that regulation...

  12. 76 FR 60357 - Golden Nematode; Removal of Regulated Areas

    Science.gov (United States)

    2011-09-29

    .... APHIS-2011-0036] Golden Nematode; Removal of Regulated Areas AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Interim rule and request for comments. SUMMARY: We are amending the golden nematode... infested areas. Surveys have shown that the fields in these two townships are free of golden nematode, and...

  13. How many bootstrap replicates are necessary?

    Science.gov (United States)

    Pattengale, Nicholas D; Alipour, Masoud; Bininda-Emonds, Olaf R P; Moret, Bernard M E; Stamatakis, Alexandros

    2010-03-01

    Phylogenetic bootstrapping (BS) is a standard technique for inferring confidence values on phylogenetic trees that is based on reconstructing many trees from minor variations of the input data, trees called replicates. BS is used with all phylogenetic reconstruction approaches, but we focus here on one of the most popular, maximum likelihood (ML). Because ML inference is so computationally demanding, it has proved too expensive to date to assess the impact of the number of replicates used in BS on the relative accuracy of the support values. For the same reason, a rather small number (typically 100) of BS replicates are computed in real-world studies. Stamatakis et al. recently introduced a BS algorithm that is 1 to 2 orders of magnitude faster than previous techniques, while yielding qualitatively comparable support values, making an experimental study possible. In this article, we propose stopping criteria--that is, thresholds computed at runtime to determine when enough replicates have been generated--and we report on the first large-scale experimental study to assess the effect of the number of replicates on the quality of support values, including the performance of our proposed criteria. We run our tests on 17 diverse real-world DNA--single-gene as well as multi-gene--datasets, which include 125-2,554 taxa. We find that our stopping criteria typically stop computations after 100-500 replicates (although the most conservative criterion may continue for several thousand replicates) while producing support values that correlate at better than 99.5% with the reference values on the best ML trees. Significantly, we also find that the stopping criteria can recommend very different numbers of replicates for different datasets of comparable sizes. Our results are thus twofold: (i) they give the first experimental assessment of the effect of the number of BS replicates on the quality of support values returned through BS, and (ii) they validate our proposals for

  14. MOF Suppresses Replication Stress and Contributes to Resolution of Stalled Replication Forks.

    Science.gov (United States)

    Singh, Dharmendra Kumar; Pandita, Raj K; Singh, Mayank; Chakraborty, Sharmistha; Hambarde, Shashank; Ramnarain, Deepti; Charaka, Vijaya; Ahmed, Kazi Mokim; Hunt, Clayton R; Pandita, Tej K

    2018-03-15

    The human MOF (hMOF) protein belongs to the MYST family of histone acetyltransferases and plays a critical role in transcription and the DNA damage response. MOF is essential for cell proliferation; however, its role during replication and replicative stress is unknown. Here we demonstrate that cells depleted of MOF and under replicative stress induced by cisplatin, hydroxyurea, or camptothecin have reduced survival, a higher frequency of S-phase-specific chromosome damage, and increased R-loop formation. MOF depletion decreased replication fork speed and, when combined with replicative stress, also increased stalled replication forks as well as new origin firing. MOF interacted with PCNA, a key coordinator of replication and repair machinery at replication forks, and affected its ubiquitination and recruitment to the DNA damage site. Depletion of MOF, therefore, compromised the DNA damage repair response as evidenced by decreased Mre11, RPA70, Rad51, and PCNA focus formation, reduced DNA end resection, and decreased CHK1 phosphorylation in cells after exposure to hydroxyurea or cisplatin. These results support the argument that MOF plays an important role in suppressing replication stress induced by genotoxic agents at several stages during the DNA damage response. Copyright © 2018 American Society for Microbiology.

  15. Remote Sensing of Parasitic Nematodes in Plants

    Science.gov (United States)

    Lawrence, Gary W.; King, Roger; Kelley, Amber T.; Vickery, John

    2007-01-01

    A method and apparatus for remote sensing of parasitic nematodes in plants, now undergoing development, is based on measurement of visible and infrared spectral reflectances of fields where the plants are growing. Initial development efforts have been concentrated on detecting reniform nematodes (Rotylenchulus reniformis) in cotton plants, because of the economic importance of cotton crops. The apparatus includes a hand-held spectroradiometer. The readings taken by the radiometer are processed to extract spectral reflectances at sixteen wavelengths between 451 and 949 nm that, taken together, have been found to be indicative of the presence of Rotylenchulus reniformis. The intensities of the spectral reflectances are used to estimate the population density of the nematodes in an area from which readings were taken.

  16. Nematode taxonomy: from morphology to metabarcoding

    Science.gov (United States)

    Ahmed, M.; Sapp, M.; Prior, T.; Karssen, G.; Back, M.

    2015-11-01

    Nematodes represent a species rich and morphologically diverse group of metazoans inhabiting both aquatic and terrestrial environments. Their role as biological indicators and as key players in nutrient cycling has been well documented. Some groups of nematodes are also known to cause significant losses to crop production. In spite of this, knowledge of their diversity is still limited due to the difficulty in achieving species identification using morphological characters. Molecular methodology has provided very useful means of circumventing the numerous limitations associated with classical morphology based identification. We discuss herein the history and the progress made within the field of nematode systematics, the limitations of classical taxonomy and how the advent of high throughput sequencing is facilitating advanced ecological and molecular studies.

  17. Pasteuria spp.: Systematics and Phylogeny of These Bacterial Parasites of Phytopathogenic Nematodes.

    Science.gov (United States)

    Preston, J F; Dickson, D W; Maruniak, J E; Nong, G; Brito, J A; Schmidt, L M; Giblin-Davis, R M

    2003-06-01

    Pasteuria spp. include endospore-forming bacterial pathogens of cladoceran crustaceans and plant-parasitic nematodes. Propagation of these nematode pathogens requires attachment of soilborne endospores to nematode hosts, infection, growth, sporulation, and release of endospores to repeat the cycle of infection and propagation. The ability of these bacteria to suppress the levels of plant-parasitic nematodes in the field has made them particularly promising candidates for biocontrol of nematode diseases of plants. Genes encoding 16S ribosomal RNA have been sequenced for the cladoceran (water flea) parasite and type species, Pasteuria ramosa, and for Pasteuria spp. isolated from root-knot (Meloidogyne arenaria race 1 and Meloidogyne sp.), soybean cyst (Heterodera glycines), and sting (Belonolaimus longicaudatus) nematodes. These have provided a phylogenetic basis for their designation to a distinct clade within the family Alicyclobacillaceae of the gram-positive endospore-forming bacteria. Two apparent biotypes of P. penetrans demonstrating a host preference for different Meloidogyne spp. showed identical 16S rDNA sequences, suggesting host-recognition evolves within a given species. The sequences of genes encoding sporulation transcription factors, sigE and sigF, from P. penetrans biotype P-20 show different phylogenetic relationships to other endospore-forming bacteria, supporting their application to further discriminate Pasteuria spp. and biotypes. Distribution of an adhesin-associated epitope on polypeptides from different Pasteuria isolates provides an immunochemical approach to differentiate species and biotypes with specific host preferences. Application of bioinformatics to genomic data, as well as further characterization of the biochemical basis for host recognition, will facilitate development of Pasteuria spp. as benign alternatives to chemical nematicides.

  18. Venereal worms: sexually transmitted nematodes in the decorated cricket.

    Science.gov (United States)

    Luong, L T; Platzer, E G; Zuk, M; Giblin-Davis, R M

    2000-06-01

    The nematode, Mehdinema alii, occurs in the alimentary canal of the decorated cricket Gryllodes sigillatus. Adult nematodes occur primarily in the hindgut of mature male crickets, whereas juvenile nematodes are found in the genital chambers of mature male and female crickets. Here, we present experimental evidence for the venereal transmission of M. alii in G. sigillatus. Infectivity experiments were conducted to test for transmission via oral-fecal contamination, same-sex contact, and copulation. The infective dauers of the nematode are transferred from male to female crickets during copulation. Adult female crickets harboring infective dauers subsequently transfer the nematode to their next mates. Thus, M. alii is transmitted sexually during copulation.

  19. An improved method for generating axenic entomopathogenic nematodes.

    Science.gov (United States)

    Yadav, Shruti; Shokal, Upasana; Forst, Steven; Eleftherianos, Ioannis

    2015-09-19

    Steinernema carpocapsae are parasitic nematodes that invade and kill insects. The nematodes are mutualistically associated with the bacteria Xenorhabdus nematophila and together form an excellent model to study pathogen infection processes and host anti-nematode/antibacterial immune responses. To determine the contribution of S. carpocapsae and their associated X. nematophila to the successful infection of insects as well as to investigate the interaction of each mutualistic partner with the insect immune system, it is important to develop and establish robust methods for generating nematodes devoid of their bacteria. To produce S. carpocapsae nematodes without their associated X. nematophila bacteria, we have modified a previous method, which involves the use of a X. nematophila rpoS mutant strain that fails to colonize the intestine of the worms. We confirmed the absence of bacteria in the nematodes using a molecular diagnostic and two rounds of an axenicity assay involving appropriate antibiotics and nematode surface sterilization. We used axenic and symbiotic S. carpocapsae to infect Drosophila melanogaster larvae and found that both types of nematodes were able to cause insect death at similar rates. Generation of entomopathogenic nematodes lacking their mutualistic bacteria provides an excellent tool to dissect the molecular and genetic basis of nematode parasitism and to identify the insect host immune factors that participate in the immune response against nematode infections.

  20. Cryopreservation of roe deer abomasal nematodes for morphological identification.

    Science.gov (United States)

    Beraldo, Paola; Pascotto, Ernesto

    2014-02-01

    Conventional methods to preserve adult nematodes for taxonomic purposes involve the use of fixative or clearing solutions (alcohol, formaldehyde, AFA and lactophenol), which cause morphological alterations and are toxic. The aim of this study is to propose an alternative method based on glycerol-cryopreservation of nematodes for their subsequent identification. Adults of trichostrongylid nematodes from the abomasum of roe deer (Capreolus capreolus Linnaeus) were glycerol-cryopreserved and compared with those fixed in formaldehyde, fresh and frozen without cryoprotectans. Morphology, transparency and elasticity of the anterior and posterior portion of male nematodes were compared, especially the caudal cuticular bursa and genital accessories. The method presented is quick and easy to use, and the quality of nematode specimens is better than that of nematodes fixed by previously used fixatives. Moreover, glycerol cryopreserved nematodes can be stored for a long time at -20 degrees C in perfect condition and they could be suitable for further analyses, such as histological or ultrastructural examinations.

  1. Meiobenthos assemblages in the mekong estuarine system with special focus on free-living marine nematodes

    Science.gov (United States)

    Quang, Ngo Xuan; Vanreusel, Ann; Smol, Nic; Chau, Nguyen Ngoc

    2010-12-01

    Meiobenthos assemblages in eight estuaries of the Mekong river system were investigated in August 2008 (from the Cua Tieu estuary to the Tran De estuary). In each estuary, one sampling station was established for meiobenthos sampling. Twelve major taxa of meiobenthos were recorded in this estuarine system, including Nematoda, Copepoda, Turbellaria, Polychaeta, Oligochaeta, Tardigrada, Bivalvia, Ostracoda, Amphipoda, Cumacea, Gastrotricha, Gastropoda, and Crustacean Nauplii larvae. The densities of the meiobenthos range from 581 to 3168 inds/10 cm2. Nematodes always occupy the highest numbers with a percentage ranging from 64-99%. There are 135 nematode genera recorded in this study with the following as dominant genera Desmodora, Leptolaimus, Halalaimus, Thalassomonhystera, Theristus, Daptonema, Rhynchonema, Parodontophora, and Oncholaimus. Although the biodiversity of the meiobenthos at higher taxa level is not high compared to other marine environments, the estimates of nematode biodiversity at the genus level indicates high values. The increase in number of genera with increasing sampling intensity illustrate that the diversity is underestimated and would have been higher if the authors had considered a larger number of individuals, more replicates per station, and more sampling stations.

  2. Evolution of Replication Machines

    Science.gov (United States)

    Yao, Nina Y.; O'Donnell, Mike E.

    2016-01-01

    The machines that decode and regulate genetic information require the translation, transcription and replication pathways essential to all living cells. Thus, it might be expected that all cells share the same basic machinery for these pathways that were inherited from the primordial ancestor cell from which they evolved. A clear example of this is found in the translation machinery that converts RNA sequence to protein. The translation process requires numerous structural and catalytic RNAs and proteins, the central factors of which are homologous in all three domains of life, bacteria, archaea and eukarya. Likewise, the central actor in transcription, RNA polymerase, shows homology among the catalytic subunits in bacteria, archaea and eukarya. In contrast, while some “gears” of the genome replication machinery are homologous in all domains of life, most components of the replication machine appear to be unrelated between bacteria and those of archaea and eukarya. This review will compare and contrast the central proteins of the “replisome” machines that duplicate DNA in bacteria, archaea and eukarya, with an eye to understanding the issues surrounding the evolution of the DNA replication apparatus. PMID:27160337

  3. Replication studies in longevity

    DEFF Research Database (Denmark)

    Varcasia, O; Garasto, S; Rizza, T

    2001-01-01

    In Danes we replicated the 3'APOB-VNTR gene/longevity association study previously carried out in Italians, by which the Small alleles (less than 35 repeats) had been identified as frailty alleles for longevity. In Danes, neither genotype nor allele frequencies differed between centenarians and 20...

  4. PCR detection of potato cyst nematode.

    Science.gov (United States)

    Reid, Alex

    2009-01-01

    Potato cyst nematode (PCN) is responsible for losses in potato production totalling millions of euros every year in the EC. It is important for growers to know which species is present in their land as this determines its subsequent use. The two species Globodera pallida and Globodera rostochiensis can be differentiated using an allele-specific PCR.

  5. [Biomorphology of gastrointestinal nematodes of small ruminants].

    Science.gov (United States)

    Giannetto, S

    2006-09-01

    Under the term gastrointestinal nematodes are included numerous parasites species of livestock belonging to the families Strongyloididae (Strongyloides), Strongylidae (Chabertia, Oesophagostomum) Trichostrongylidae (Trichostrongylus, Ostertagia, Teladorsagia, Cooperia, Marshallagia), Molineidae (Nematodirus), Ancylostomatidae (Bunostomum) and Trichuridae (Trichuris). This paper reviews the biomorphology aspects of these parasites as well as the controversy by the taxonomists in the classifications.

  6. Excretory/secretory products of anisakid nematodes

    DEFF Research Database (Denmark)

    Mehrdana, Foojan; Buchmann, Kurt

    2017-01-01

    Parasites from the family Anisakidae are widely distributed in marine fish populations worldwide and mainly nematodes of the three genera Anisakis, Pseudoterranova and Contracaecum have attracted attention due to their pathogenicity in humans. Their life cycles include invertebrates and fish as i...

  7. Potato cyst nematodes: pests of national importance

    Science.gov (United States)

    Potato cyst nematodes (PCN; G. rostochiensis and G. pallida) are internationally-recognized quarantine pests and considered the most devastating pests of potatoes due to annual worldwide yield losses estimated at 12.2%. PCNs continue to spread throughout North America and were recently detected in I...

  8. Nutritional requirements for soybean cyst nematode

    Science.gov (United States)

    Soybeans [Glycine max] are the second largest cash crop in US Agriculture, but the soybean yield is compromised by infections from Heterodera glycines, also known as Soybean Cyst Nematodes [SCN]. SCN are the most devastating pathogen or plant disease soybean producers confront. This obligate parasi...

  9. Natural product synthesis: Making nematodes nervous

    Science.gov (United States)

    Snyder, Scott A.

    2011-06-01

    A highly inventive route for the synthesis of a key substance that stimulates potato cyst nematodes to hatch has been developed. This discovery has potential to impact food supplies, as treatment of crops with this compound could alleviate the devastating effect of these parasites.

  10. RNA interference in plant parasitic nematodes

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... grower preference or by government restrictions to limit the environmental ... risks associated with chemical control and (c) the pro- vision of ... certain model organisms. The first ... reproductive system (Lilley et al., 2005b), sperm (Urwin .... interference of dual oxidase in the plant nematode Meloidogyne.

  11. Nematodes: Model Organisms in High School Biology

    Science.gov (United States)

    Bliss, TJ; Anderson, Margery; Dillman, Adler; Yourick, Debra; Jett, Marti; Adams, Byron J.; Russell, RevaBeth

    2007-01-01

    In a collaborative effort between university researchers and high school science teachers, an inquiry-based laboratory module was designed using two species of insecticidal nematodes to help students apply scientific inquiry and elements of thoughtful experimental design. The learning experience and model are described in this article. (Contains 4…

  12. Nematode survival in relation to soil moisture

    NARCIS (Netherlands)

    Simons, W.R.

    1973-01-01

    Established nematode populations are very persistent in the soil. It is known that they need sufficient soil moisture for movement, feeding and reproduction (fig. 5), and that there are adverse soil moisture conditions which they cannot survive. The influence of soil moisture on survival

  13. Unifying the functional diversity in natural and cultivated soils using the overall body-mass distribution of nematodes.

    Science.gov (United States)

    Mulder, Christian; Maas, Rob

    2017-11-28

    Sustainable use of our soils is a key goal for environmental protection. As many ecosystem services are supported belowground at different trophic levels by nematodes, soil nematodes are expected to provide objective metrics for biological quality to integrate physical and chemical soil variables. Trait measurements of body mass carried out at the individual level can in this way be correlated with environmental properties that influence the performance of soil biota. Soil samples were collected across 200 sites (4 soil types and 5 land-use types resulting in 9 combinations) during a long-term monitoring programme in the Netherlands and the functional diversity of nematode communities was investigated. Using three commonly used functional diversity indices applicable to single traits (Divergence, Evenness and Richness), a unified index of overall body-mass distribution is proposed to better illustrate the application of functional metrics as a descriptor of land use. Effects of land use and soil chemistry on the functional diversity of nematodes were demonstrated and a combination of environmental factors accounts for the low functional value of Scots Pine forest soils in comparison to the high functional value of heathland soils, whereas human factors account for the low functional and chemical values of arable fields. These findings show an unexpected high functional vulnerability of nematodes inhabiting clay-rich soils in comparison to sandy soils and support the notion that soil C:N ratio is a major driver of biodiversity. The higher the C:N ratio, the higher the overall diversity, as soil nematodes cope better with nutrient-poor agroecosystems under less intense fertilization. A trait-based way focusing on size distribution of nematodes is proposed to maintain environmental health by monitoring the overall diversity in soil biota, keeping agriculture and forestry sustainable.

  14. Evidence supporting a role for TopBP1 and Brd4 in the initiation but not continuation of human papillomavirus 16 E1/E2-mediated DNA replication.

    Science.gov (United States)

    Gauson, Elaine J; Donaldson, Mary M; Dornan, Edward S; Wang, Xu; Bristol, Molly; Bodily, Jason M; Morgan, Iain M

    2015-05-01

    To replicate the double-stranded human papillomavirus 16 (HPV16) DNA genome, viral proteins E1 and E2 associate with the viral origin of replication, and E2 can also regulate transcription from adjacent promoters. E2 interacts with host proteins in order to regulate both transcription and replication; TopBP1 and Brd4 are cellular proteins that interact with HPV16 E2. Previous work with E2 mutants demonstrated the Brd4 requirement for the transactivation properties of E2, while TopBP1 is required for DNA replication induced by E2 from the viral origin of replication in association with E1. More-recent studies have also implicated Brd4 in the regulation of DNA replication by E2 and E1. Here, we demonstrate that both TopBP1 and Brd4 are present at the viral origin of replication and that interaction with E2 is required for optimal initiation of DNA replication. Both cellular proteins are present in E1-E2-containing nuclear foci, and the viral origin of replication is required for the efficient formation of these foci. Short hairpin RNA (shRNA) against either TopBP1 or Brd4 destroys the E1-E2 nuclear bodies but has no effect on E1-E2-mediated levels of DNA replication. An E2 mutation in the context of the complete HPV16 genome that compromises Brd4 interaction fails to efficiently establish episomes in primary human keratinocytes. Overall, the results suggest that interactions between TopBP1 and E2 and between Brd4 and E2 are required to correctly initiate DNA replication but are not required for continuing DNA replication, which may be mediated by alternative processes such as rolling circle amplification and/or homologous recombination. Human papillomavirus 16 (HPV16) is causative in many human cancers, including cervical and head and neck cancers, and is responsible for the annual deaths of hundreds of thousands of people worldwide. The current vaccine will save lives in future generations, but antivirals targeting HPV16 are required for the alleviation of disease

  15. Deep-sea nematodes actively colonise sediments, irrespective of the presence of a pulse of organic matter: results from an in-situ experiment.

    Directory of Open Access Journals (Sweden)

    Katja Guilini

    Full Text Available A colonisation experiment was performed in situ at 2500 m water depth at the Arctic deep-sea long-term observatory HAUSGARTEN to determine the response of deep-sea nematodes to disturbed, newly available patches, enriched with organic matter. Cylindrical tubes,laterally covered with a 500 µm mesh, were filled with azoic deep-sea sediment and (13C-labelled food sources (diatoms and bacteria. After 10 days of incubation the tubes were analysed for nematode response in terms of colonisation and uptake. Nematodes actively colonised the tubes, however with densities that only accounted for a maximum of 2.13% (51 ind.10 cm(-2 of the ambient nematode assemblages. Densities did not differ according to the presence or absence of organic matter, nor according to the type of organic matter added. The fact that the organic matter did not function as an attractant to nematodes was confirmed by the absence of notable (13C assimilation by the colonising nematodes. Overall, colonisation appears to be a process that yields reproducible abundance and diversity patterns, with certain taxa showing more efficiency. Together with the high variability between the colonising nematode assemblages, this lends experimental support to the existence of a spatio-temporal mosaic that emerges from highly localised, partially stochastic community dynamics.

  16. Top 10 plant-parasitic nematodes in molecular plant pathology.

    Science.gov (United States)

    Jones, John T; Haegeman, Annelies; Danchin, Etienne G J; Gaur, Hari S; Helder, Johannes; Jones, Michael G K; Kikuchi, Taisei; Manzanilla-López, Rosa; Palomares-Rius, Juan E; Wesemael, Wim M L; Perry, Roland N

    2013-12-01

    The aim of this review was to undertake a survey of researchers working with plant-parasitic nematodes in order to determine a 'top 10' list of these pathogens based on scientific and economic importance. Any such list will not be definitive as economic importance will vary depending on the region of the world in which a researcher is based. However, care was taken to include researchers from as many parts of the world as possible when carrying out the survey. The top 10 list emerging from the survey is composed of: (1) root-knot nematodes (Meloidogyne spp.); (2) cyst nematodes (Heterodera and Globodera spp.); (3) root lesion nematodes (Pratylenchus spp.); (4) the burrowing nematode Radopholus similis; (5) Ditylenchus dipsaci; (6) the pine wilt nematode Bursaphelenchus xylophilus; (7) the reniform nematode Rotylenchulus reniformis; (8) Xiphinema index (the only virus vector nematode to make the list); (9) Nacobbus aberrans; and (10) Aphelenchoides besseyi. The biology of each nematode (or nematode group) is reviewed briefly. © 2013 BSPP AND JOHN WILEY & SONS LTD.

  17. Replication Protein A (RPA) Phosphorylation Prevents RPA Association with Replication Centers

    OpenAIRE

    Vassin, Vitaly M.; Wold, Marc S.; Borowiec, James A.

    2004-01-01

    Mammalian replication protein A (RPA) undergoes DNA damage-dependent phosphorylation at numerous sites on the N terminus of the RPA2 subunit. To understand the functional significance of RPA phosphorylation, we expressed RPA2 variants in which the phosphorylation sites were converted to aspartate (RPA2D) or alanine (RPA2A). Although RPA2D was incorporated into RPA heterotrimers and supported simian virus 40 DNA replication in vitro, the RPA2D mutant was selectively unable to associate with re...

  18. The bacterial community of entomophilic nematodes and host beetles.

    Science.gov (United States)

    Koneru, Sneha L; Salinas, Heilly; Flores, Gilberto E; Hong, Ray L

    2016-05-01

    Insects form the most species-rich lineage of Eukaryotes and each is a potential host for organisms from multiple phyla, including fungi, protozoa, mites, bacteria and nematodes. In particular, beetles are known to be associated with distinct bacterial communities and entomophilic nematodes. While entomopathogenic nematodes require symbiotic bacteria to kill and reproduce inside their insect hosts, the microbial ecology that facilitates other types of nematode-insect associations is largely unknown. To illuminate detailed patterns of the tritrophic beetle-nematode-bacteria relationship, we surveyed the nematode infestation profiles of scarab beetles in the greater Los Angeles area over a five-year period and found distinct nematode infestation patterns for certain beetle hosts. Over a single season, we characterized the bacterial communities of beetles and their associated nematodes using high-throughput sequencing of the 16S rRNA gene. We found significant differences in bacterial community composition among the five prevalent beetle host species, independent of geographical origin. Anaerobes Synergistaceae and sulphate-reducing Desulfovibrionaceae were most abundant in Amblonoxia beetles, while Enterobacteriaceae and Lachnospiraceae were common in Cyclocephala beetles. Unlike entomopathogenic nematodes that carry bacterial symbionts, insect-associated nematodes do not alter the beetles' native bacterial communities, nor do their microbiomes differ according to nematode or beetle host species. The conservation of Diplogastrid nematodes associations with Melolonthinae beetles and sulphate-reducing bacteria suggests a possible link between beetle-bacterial communities and their associated nematodes. Our results establish a starting point towards understanding the dynamic interactions between soil macroinvertebrates and their microbiota in a highly accessible urban environment. © 2016 John Wiley & Sons Ltd.

  19. Some Plant Parasitic Nematodes of Fruit Trees in Northern Khorasan Province, Iran

    Directory of Open Access Journals (Sweden)

    N. Heidarzadeh

    2017-08-01

    Full Text Available Introduction: Nematodes (Phylum Nematoda are considered as one of the most abundant and diverse animals on earth. They are found in terrestrial, freshwater, brackish, and marine environments and play important ecological roles in soil ecosystems. The order Tylenchida includes the largest and economically most important group of plant-parasitic nematodes so they have always received ample taxonomic attention. Many plant parasitic nematode species are important pests of fruit trees. They damage the plant by directly attacking roots and subsequently predisposing them to secondary infections by bacteria, fungi by causing replant and pre-plant problems of orchards and also by transmission of viruses. Plant parasitic nematodes feed on a plant root system, ability to take up water and minerals and to transport nutrients to the shoot. This restricts root growth reduce plant vitality and inhibits shoot growth, the combination of which results in decreased in quality and yield. The economically most important species belong to the genera Meloidogyne, Pratylenchus, criconemella, Logidorus, Xiphinema, Trichodorus and Paratrichodorus and are widely distributed in fruit orchards throughout the world. Nematode species are classically defined on the basis of these qualitative and quantitative characters. Although morphological information might help species diagnostics, these characters are homoplasious features in many cases and do not adequately consider the possibility of convergent evolution. As a result, new species descriptions are increasingly supported by molecular evidence. However, the study of morphology remains a critical necessity as morphology is the primary interface of an organism with its environment with key implications for development and ecology. Therefore, a more robust phylogeny based on a combination of morphological and molecular approaches is needed to clarify important relationships within Tylenchomorpha. The purpose of the present

  20. EFFICACY OF ENDOPHYTIC BACTERIA IN REDUCING PLANT PARASITIC NEMATODE Pratylenchus brachyurus

    Directory of Open Access Journals (Sweden)

    Rita Harni

    2014-04-01

    Full Text Available Pratylenchus brachyurus is a major parasitic nematode on patchouli that reduces plant production up to 85%. The use of endophytic bacteria is promising for controlling nematode and promoting plant growth through production of phytohormones and enhancing the availability of soil nutrients. The objective of the study was to evaluate the efficacy of endophytic bacteria to control P. brachyurus on patchouli plant and its influence on plant productions (plant fresh weight and patchouli oil. The study was conducted at Cimanggu Experimental Garden and Laboratory of the Indonesian Spice and Medicinal Crops Research Institute (ISMECRI, Bogor, West Java. The experi-ment was designed in a randomized block with seven treatments and eight replications; each replication consisted of 10 plants. The treatments evaluated were five isolates of endophytic bacteria (Achromobacter xylosoxidans TT2, Alcaligenes faecalis NJ16, Pseudomonas putida EH11, Bacillus cereus MSK and Bacillus subtilis NJ57, synthetic nematicide as a reference, and non-treated plant as a control.  Four-week old patchouli plants of cv. Sidikalang were treated by soaking the roots in suspension of endophytic bacteria (109 cfu  ml-1 for one hour before trans-planting to the field. At one month after planting, the plants were drenched with the bacterial suspension as much as 100 ml per plant. The results showed that applications of the endophytic bacteria could suppress the nematode populations (52.8-80% and increased plant weight (23.62-57.48% compared to the control. The isolate of endophytic bacterium Achromobacter xylosoxidans TT2 was the best and comparable with carbofuran.

  1. Identification of vacuoles containing extraintestinal differentiated forms of Legionella pneumophila in colonized Caenorhabditis elegans soil nematodes.

    Science.gov (United States)

    Hellinga, Jacqueline R; Garduño, Rafael A; Kormish, Jay D; Tanner, Jennifer R; Khan, Deirdre; Buchko, Kristyn; Jimenez, Celine; Pinette, Mathieu M; Brassinga, Ann Karen C

    2015-08-01

    Legionella pneumophila, a causative agent of Legionnaires' disease, is a facultative intracellular parasite of freshwater protozoa. Legionella pneumophila features a unique developmental network that involves several developmental forms including the infectious cyst forms. Reservoirs of L. pneumophila include natural and man-made freshwater systems; however, recent studies have shown that isolates of L. pneumophila can also be obtained directly from garden potting soil suggesting the presence of an additional reservoir. A previous study employing the metazoan Caenorhabditis elegans, a member of the Rhabditidae family of free-living soil nematodes, demonstrated that the intestinal lumen can be colonized with L. pneumophila. While both replicative forms and differentiated forms were observed in C. elegans, these morphologically distinct forms were initially observed to be restricted to the intestinal lumen. Using live DIC imaging coupled with focused transmission electron microscopy analyses, we report here that L. pneumophila is able to invade and establish Legionella-containing vacuoles (LCVs) in the intestinal cells. In addition, LCVs containing replicative and differentiated cyst forms were observed in the pseudocoelomic cavity and gonadal tissue of nematodes colonized with L. pneumophila. Furthermore, establishment of LCVs in the gonadal tissue was Dot/Icm dependent and required the presence of the endocytic factor RME-1 to gain access to maturing oocytes. Our findings are novel as this is the first report, to our knowledge, of extraintestinal LCVs containing L. pneumophila cyst forms in C. elegans tissues, highlighting the potential of soil-dwelling nematodes as an alternate environmental reservoir for L. pneumophila. © 2015 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  2. Damage-associated responses of the host contribute to defence against cyst nematodes but not root-knot nematodes.

    Science.gov (United States)

    Shah, Syed Jehangir; Anjam, Muhammad Shahzad; Mendy, Badou; Anwer, Muhammad Arslan; Habash, Samer S; Lozano-Torres, Jose L; Grundler, Florian M W; Siddique, Shahid

    2017-12-16

    When nematodes invade and subsequently migrate within plant roots, they generate cell wall fragments (in the form of oligogalacturonides; OGs) that can act as damage-associated molecular patterns and activate host defence responses. However, the molecular mechanisms mediating damage responses in plant-nematode interactions remain unexplored. Here, we characterized the role of a group of cell wall receptor proteins in Arabidopsis, designated as polygalacturonase-inhibiting proteins (PGIPs), during infection with the cyst nematode Heterodera schachtii and the root-knot nematode Meloidogyne incognita. PGIPs are encoded by a family of two genes in Arabidopsis, and are involved in the formation of active OG elicitors. Our results show that PGIP gene expression is strongly induced in response to cyst nematode invasion of roots. Analyses of loss-of-function mutants and overexpression lines revealed that PGIP1 expression attenuates infection of host roots by cyst nematodes, but not root-knot nematodes. The PGIP1-mediated attenuation of cyst nematode infection involves the activation of plant camalexin and indole-glucosinolate pathways. These combined results provide new insights into the molecular mechanisms underlying plant damage perception and response pathways during infection by cyst and root-knot nematodes, and establishes the function of PGIP in plant resistance to cyst nematodes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  3. Mechanisms of DNA replication termination.

    Science.gov (United States)

    Dewar, James M; Walter, Johannes C

    2017-08-01

    Genome duplication is carried out by pairs of replication forks that assemble at origins of replication and then move in opposite directions. DNA replication ends when converging replication forks meet. During this process, which is known as replication termination, DNA synthesis is completed, the replication machinery is disassembled and daughter molecules are resolved. In this Review, we outline the steps that are likely to be common to replication termination in most organisms, namely, fork convergence, synthesis completion, replisome disassembly and decatenation. We briefly review the mechanism of termination in the bacterium Escherichia coli and in simian virus 40 (SV40) and also focus on recent advances in eukaryotic replication termination. In particular, we discuss the recently discovered E3 ubiquitin ligases that control replisome disassembly in yeast and higher eukaryotes, and how their activity is regulated to avoid genome instability.

  4. Chromatin replication and epigenome maintenance

    DEFF Research Database (Denmark)

    Alabert, Constance; Groth, Anja

    2012-01-01

    Stability and function of eukaryotic genomes are closely linked to chromatin structure and organization. During cell division the entire genome must be accurately replicated and the chromatin landscape reproduced on new DNA. Chromatin and nuclear structure influence where and when DNA replication...... initiates, whereas the replication process itself disrupts chromatin and challenges established patterns of genome regulation. Specialized replication-coupled mechanisms assemble new DNA into chromatin, but epigenome maintenance is a continuous process taking place throughout the cell cycle. If DNA...

  5. Small RNAs and extracellular vesicles in filarial nematodes: From nematode development to diagnostics.

    Science.gov (United States)

    Quintana, J F; Babayan, S A; Buck, A H

    2017-02-01

    Parasitic nematodes have evolved sophisticated mechanisms to communicate with their hosts in order to survive and successfully establish an infection. The transfer of RNA within extracellular vesicles (EVs) has recently been described as a mechanism that could contribute to this communication in filarial nematodes. It has been shown that these EVs are loaded with several types of RNAs, including microRNAs, leading to the hypothesis that parasites could actively use these molecules to manipulate host gene expression and to the exciting prospect that these pathways could result in new diagnostic and therapeutic strategies. Here, we review the literature on the diverse RNAi pathways that operate in nematodes and more specifically our current knowledge of extracellular RNA (exRNA) and EVs derived from filarial nematodes in vitro and within their hosts. We further detail some of the issues and questions related to the capacity of RNA-mediated communication to function in parasite-host interactions and the ability of exRNA to enable us to distinguish and detect different nematode parasites in their hosts. © 2016 The Authors. Parasite Immunology published by John Wiley & Sons Ltd.

  6. Plant actin cytoskeleton re-modeling by plant parasitic nematodes.

    Science.gov (United States)

    Engler, Janice de Almeida; Rodiuc, Natalia; Smertenko, Andrei; Abad, Pierre

    2010-03-01

    The cytoskeleton is an important component of the plant's defense mechanism against the attack of pathogenic organisms. Plants however, are defenseless against parasitic root-knot and cyst nematodes and respond to the invasion by the development of a special feeding site that supplies the parasite with nutrients required for the completion of its life cycle. Recent studies of nematode invasion under treatment with cytoskeletal drugs and in mutant plants where normal functions of the cytoskeleton have been affected, demonstrate the importance of the cytoskeleton in the establishment of a feeding site and successful nematode reproduction. It appears that in the case of microfilaments, nematodes hijack the intracellular machinery that regulates actin dynamics and modulate the organization and properties of the actin filament network. Intervening with this process reduces the nematode infection efficiency and inhibits its life cycle. This discovery uncovers a new pathway that can be exploited for the protection of plants against nematodes.

  7. Caenorhabditis elegans: nature and nurture gift to nematode parasitologists.

    Science.gov (United States)

    Salinas, Gustavo; Risi, Gastón

    2017-12-06

    The free-living nematode Caenorhabditis elegans is the simplest animal model organism to work with. Substantial knowledge and tools have accumulated over 50 years of C. elegans research. The use of C. elegans relating to parasitic nematodes from a basic biology standpoint or an applied perspective has increased in recent years. The wealth of information gained on the model organism, the use of the powerful approaches and technologies that have advanced C. elegans research to parasitic nematodes and the enormous success of the omics fields have contributed to bridge the divide between C. elegans and parasite nematode researchers. We review key fields, such as genomics, drug discovery and genetics, where C. elegans and nematode parasite research have convened. We advocate the use of C. elegans as a model to study helminth metabolism, a neglected area ready to advance. How emerging technologies being used in C. elegans can pave the way for parasitic nematode research is discussed.

  8. Replication Research and Special Education

    Science.gov (United States)

    Travers, Jason C.; Cook, Bryan G.; Therrien, William J.; Coyne, Michael D.

    2016-01-01

    Replicating previously reported empirical research is a necessary aspect of an evidence-based field of special education, but little formal investigation into the prevalence of replication research in the special education research literature has been conducted. Various factors may explain the lack of attention to replication of special education…

  9. Temporal organization of cellular self-replication

    Science.gov (United States)

    Alexandrov, Victor; Pugatch, Rami

    Recent experiments demonstrate that single cells grow exponentially in time. A coarse grained model of cellular self-replication is presented based on a novel concept - the cell is viewed as a self-replicating queue. This allows to have a more fundamental look into various temporal organizations and, importantly, the inherent non-Markovianity of noise distributions. As an example, the distribution of doubling times can be inferred and compared to single cell experiments in bacteria. We observe data collapse upon scaling by the average doubling time for different environments and present an inherent task allocation trade-off. Support from the Simons Center for Systems Biology, IAS, Princeon.

  10. The replication of expansive production knowledge

    DEFF Research Database (Denmark)

    Wæhrens, Brian Vejrum; Yang, Cheng; Madsen, Erik Skov

    2012-01-01

    Purpose – With the aim to support offshore production line replication, this paper specifically aims to explore the use of templates and principles to transfer expansive productive knowledge embedded in a production line and understand the contingencies that influence the mix of these approaches......; and (2) rather than being viewed as alternative approaches, templates and principles should be seen as complementary once the transfer motive moves beyond pure replication. Research limitations – The concepts introduced in this paper were derived from two Danish cases. While acceptable for theory...

  11. Effect of long-term combined application of organic and inorganic fertilizers on soil nematode communities within aggregates.

    Science.gov (United States)

    Zhang, Zhiyong; Zhang, Xiaoke; Mahamood, Md; Zhang, Shuiqing; Huang, Shaomin; Liang, Wenju

    2016-08-09

    A long-term fertilization experiment was conducted to examine the effects of different fertilization practices on nematode community composition within aggregates in a wheat-maize rotation system. The study was a randomized complete block design with three replicates. The experiment involved the following four treatments: no fertilizer, inorganic N, P and K fertilizer (NPK), NPK plus manure (NPKM) and NPK plus maize straw (NPKS). Soil samples were taken at 0-20 cm depth during the wheat harvest stage. Based on our results, NPKS contributed to soil aggregation and moisture retention, with a positive effect on soil total nitrogen accumulation, particularly within small macroaggregates (0.25-1 mm) and microaggregates (fertilizer application effectively improved soil physicochemical properties and were also beneficial for nematode survival within small aggregate size fractions.

  12. Molecular relationships between closely related strains and species of nematodes

    Science.gov (United States)

    Butler, M. H.; Wall, S. M.; Luehrsen, K. R.; Fox, G. E.; Hecht, R. M.

    1981-01-01

    Electrophoretic comparisons have been made for 24 enzymes in the Bergerac and Bristol strains of Caenorhabditis elegans and the related species, Caenorhabditis briggsae. No variation was detected between the two strains of C. elegans. In contrast, the two species, C. elegans and C. briggsae exhibited electrophoretic differences in 22 of 24 enzymes. A consensus 5S rRNA sequence was determined for C. elegans and found to be identical to that from C. briggsae. By analogy with other species with relatively well established fossil records it can be inferred that the time of divergence between the two nematode species is probably in the tens of millions of years. The limited anatomical evolution during a time period in which proteins undergo extensive changes supports the hypothesis that anatomical evolution is not dependent on overall protein changes.

  13. Entomopathogenic nematode food webs in an ancient, mining pollution gradient in Spain.

    Science.gov (United States)

    Campos-Herrera, Raquel; Rodríguez Martín, José Antonio; Escuer, Miguel; García-González, María Teresa; Duncan, Larry W; Gutiérrez, Carmen

    2016-12-01

    Mining activities pollute the environment with by-products that cause unpredictable impacts in surrounding areas. Cartagena-La Unión mine (Southeastern-Spain) was active for >2500years. Despite its closure in 1991, high concentrations of metals and waste residues remain in this area. A previous study using nematodes suggested that high lead content diminished soil biodiversity. However, the effects of mine pollution on specific ecosystem services remain unknown. Entomopathogenic nematodes (EPN) play a major role in the biocontrol of insect pests. Because EPNs are widespread throughout the world, we speculated that EPNs would be present in the mined areas, but at increased incidence with distance from the pollution focus. We predicted that the natural enemies of nematodes would follow a similar spatial pattern. We used qPCR techniques to measure abundance of five EPN species, five nematophagous fungi species, two bacterial ectoparasites of EPNs and one group of free-living nematodes that compete for the insect-cadaver. The study comprised 193 soil samples taken from mining sites, natural areas and agricultural fields. The highest concentrations of iron and zinc were detected in the mined area as was previously described for lead, cadmium and nickel. Molecular tools detected very low numbers of EPNs in samples found to be negative by insect-baiting, demonstrating the importance of the approach. EPNs were detected at low numbers in 13% of the localities, without relationship to heavy-metal concentrations. Only Acrobeloides-group nematodes were inversely related to the pollution gradient. Factors associated with agricultural areas explained 98.35% of the biotic variability, including EPN association with agricultural areas. Our study suggests that EPNs have adapted to polluted habitats that might support arthropod hosts. By contrast, the relationship between abundance of Acrobeloides-group and heavy-metal levels, revealed these taxa as especially well suited bio

  14. Entomopathogenic and plant pathogenic nematodes as opposing forces in agriculture.

    Science.gov (United States)

    Kenney, Eric; Eleftherianos, Ioannis

    2016-01-01

    Plant-parasitic nematodes are responsible for substantial damages within the agriculture industry every year, which is a challenge that has thus far gone largely unimpeded. Chemical nematicides have been employed with varying degrees of success, but their implementation can be cumbersome, and furthermore they could potentially be neutralising an otherwise positive effect from the entomopathogenic nematodes that coexist with plant-parasitic nematodes in soil environments and provide protection for plants against insect pests. Recent research has explored the potential of employing entomopathogenic nematodes to protect plants from plant-parasitic nematodes, while providing their standard degree of protection against insects. The interactions involved are highly complex, due to both the three-organism system and the assortment of variables present in a soil environment, but a strong collection of evidence has accumulated regarding the suppressive capacity of certain entomopathogenic nematodes and their mutualistic bacteria, in the context of limiting the infectivity of plant-parasitic nematodes. Specific factors produced by certain entomopathogenic nematode complexes during the process of insect infection appear to have a selectively nematicidal, or at least repellant, effect on plant-parasitic nematodes. Using this information, an opportunity has formed to adapt this relationship to large-scale, field conditions and potentially relieve the agricultural industry of one of its most substantial burdens. Copyright © 2015 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  15. Efficacy of moxidectin against nematodes in naturally infected sheep.

    Science.gov (United States)

    Coles, G C; Giordano-Fenton, D J; Tritschler, J P

    1994-07-09

    The activity of an oral drench of moxidectin against nematodes in naturally infected sheep known to harbour Nematodirus species was evaluated at doses of 0.2 and 0.4 mg/kg bodyweight. Moxidectin was 100 per cent effective against nematodes in the abomasum and 100 per cent effective against nematodes in the small intestine except for adult Trichostrongylus species, against which its efficacy was 94 per cent. It was 100 per cent effective against nematodes in the large intestine except for Trichuris ovis, against which its efficacy was 83 per cent.

  16. identification of banana varieties with resistance to nematodes in ...

    African Journals Online (AJOL)

    jen

    Institut des Sciences Agronomiques du Rwanda (ISAR), ISAR-Kibungo, Ngoma district, Rwanda ... for sustainable nematode management. Previous studies ..... Technology Development and Transfer project. ... INIBAP, Montpellier, France.

  17. 'Candidatus Pasteuria aldrichii', an obligate endoparasite of the bacterivorous nematode Bursilla.

    Science.gov (United States)

    Giblin-Davis, R M; Nong, G; Preston, J F; Williams, D S; Center, B J; Brito, J A; Dickson, D W

    2011-09-01

    A novel bacterium of the genus Pasteuria was discovered parasitizing bacterivorous nematodes of the genus Bursilla, in selected bermudagrass (Cynodon) field plots in Davie, FL, USA. Soil containing this bacterium was sampled and supplied with bi-weekly inoculations of cultured species of the genus Bursilla in order to build and maintain a source of endospores for continuous in vivo conservation of the bacteria for further study and characterization. 16S rRNA gene sequence similarities supported its congeneric ranking with other members of the genus Pasteuria that have been identified from nematodes and cladocerans. There were, however, no clear sister candidates for this organism, which supported the evidence of endospore ultrastructure and host-range studies, suggesting it belonged to a novel taxon. Because members of the genus Pasteuria cannot yet be isolated, definitive type strains could not be maintained; therefore, the name 'Candidatus Pasteuria aldrichii' is proposed for this organism.

  18. Assaying environmental nickel toxicity using model nematodes.

    Directory of Open Access Journals (Sweden)

    David Rudel

    Full Text Available Although nickel exposure results in allergic reactions, respiratory conditions, and cancer in humans and rodents, the ramifications of excess nickel in the environment for animal and human health remain largely undescribed. Nickel and other cationic metals travel through waterways and bind to soils and sediments. To evaluate the potential toxic effects of nickel at environmental contaminant levels (8.9-7,600 µg Ni/g dry weight of sediment and 50-800 µg NiCl2/L of water, we conducted assays using two cosmopolitan nematodes, Caenorhabditis elegans and Pristionchus pacificus. We assayed the effects of both sediment-bound and aqueous nickel upon animal growth, developmental survival, lifespan, and fecundity. Uncontaminated sediments were collected from sites in the Midwestern United States and spiked with a range of nickel concentrations. We found that nickel-spiked sediment substantially impairs both survival from larval to adult stages and adult longevity in a concentration-dependent manner. Further, while aqueous nickel showed no adverse effects on either survivorship or longevity, we observed a significant decrease in fecundity, indicating that aqueous nickel could have a negative impact on nematode physiology. Intriguingly, C. elegans and P. pacificus exhibit similar, but not identical, responses to nickel exposure. Moreover, P. pacificus could be tested successfully in sediments inhospitable to C. elegans. Our results add to a growing body of literature documenting the impact of nickel on animal physiology, and suggest that environmental toxicological studies could gain an advantage by widening their repertoire of nematode species.

  19. Association of nematodes and dogwood cankers.

    Science.gov (United States)

    Self, L H; Bernard, E C

    1994-03-01

    Dogwood canker is a serious production problem of unknown etiology. From May 1985 through April 1989, cankers from 290 flowering dogwood trees in 15 separate nurseries were sampled for nematodes. Seventy-three percent (213) of the cankers contained nematodes. Panagrolaimus rigidus (Schneider) Thorne (115/290) and Aphelenchoides spp. (91/290) were the most frequently collected taxa. Panagrolaimus rigidus was reared on 2% water agar with unidentified bacteria as the food source. Aphelenchoides spp. were reared in antibiotic-amended agar culture with the fungus Glomerella cingulata (Stoneman) Spauld. &Schrenk as a food source. Repeated attempts to culture Aphelenchoides spp. on dogwood callus tissue were unsuccessful. Artificially created stem wounds inoculated with combinations of Aphelenchoides spp. and P. rigidus callused completely in 60 days with no indication of canker development. Very low numbers of nematodes were recovered from inoculated trees, but P. rigidus and one Aphelenchoides sp. were efficient dispersers and occurred in treatments other than those in which they were inoculated.

  20. Assaying environmental nickel toxicity using model nematodes

    Science.gov (United States)

    Rudel, David; Douglas, Chandler; Huffnagle, Ian; Besser, John M.; Ingersoll, Christopher G.

    2013-01-01

    Although nickel exposure results in allergic reactions, respiratory conditions, and cancer in humans and rodents, the ramifications of excess nickel in the environment for animal and human health remain largely undescribed. Nickel and other cationic metals travel through waterways and bind to soils and sediments. To evaluate the potential toxic effects of nickel at environmental contaminant levels (8.9-7,600 µg Ni/g dry weight of sediment and 50-800 µg NiCl2/L of water), we conducted assays using two cosmopolitan nematodes, Caenorhabditis elegans and Pristionchus pacificus. We assayed the effects of both sediment-bound and aqueous nickel upon animal growth, developmental survival, lifespan, and fecundity. Uncontaminated sediments were collected from sites in the Midwestern United States and spiked with a range of nickel concentrations. We found that nickel-spiked sediment substantially impairs both survival from larval to adult stages and adult longevity in a concentration-dependent manner. Further, while aqueous nickel showed no adverse effects on either survivorship or longevity, we observed a significant decrease in fecundity, indicating that aqueous nickel could have a negative impact on nematode physiology. Intriguingly, C. elegansand P. pacificus exhibit similar, but not identical, responses to nickel exposure. Moreover, P. pacificus could be tested successfully in sediments inhospitable to C. elegans. Our results add to a growing body of literature documenting the impact of nickel on animal physiology, and suggest that environmental toxicological studies could gain an advantage by widening their repertoire of nematode species.

  1. Prevalence of intestinal nematodes in alcoholic patients

    Directory of Open Access Journals (Sweden)

    Zago-Gomes Maria P.

    2002-01-01

    Full Text Available We report the results of a retrospective study on the frequency of intestinal nematodes among 198 alcoholic and 440 nonalcoholic patients at the University Hospital Cassiano Antonio Moraes in Vitória, ES, Brazil. The control sample included 194 nonalcoholic patients matched according to age, sex and neighborhood and a random sample of 296 adults admitted at the same hospital. Stool examination by sedimentation method (three samples was performed in all patients. There was a significantly higher frequency of intestinal nematodes in alcoholics than in controls (35.3% and 19.2%, respectively, due to a higher frequency of Strongyloides stercoralis (21.7% and 4.1%, respectively. Disregarding this parasite, the frequency of the other nematodes was similar in both groups. The higher frequency of S. stercoralis infection in alcoholics could be explained by immune modulation and/or by some alteration in corticosteroid metabolism induced by chronic ethanol ingestion. Corticosteroid metabolites would mimic the worm ecdisteroids, that would in turn increase the fecundity of females in duodenum and survival of larvae. Consequently, the higher frequency of Strongyloides larvae in stool of alcoholics does not necessarily reflect an increased frequency of infection rate, but only an increased chance to present a positive stool examination using sedimentation methods.

  2. Soybean cyst nematode culture collections and field populations from North Carolina and Missouri reveal high incidences of infection by viruses.

    Directory of Open Access Journals (Sweden)

    Casey L Ruark

    Full Text Available Five viruses were previously discovered infecting soybean cyst nematodes (SCN; Heterodera glycines from greenhouse cultures maintained in Illinois. In this study, the five viruses [ScNV, ScPV, ScRV, ScTV, and SbCNV-5] were detected within SCN greenhouse and field populations from North Carolina (NC and Missouri (MO. The prevalence and titers of viruses in SCN from 43 greenhouse cultures and 25 field populations were analyzed using qRT-PCR. Viral titers within SCN greenhouse cultures were similar throughout juvenile development, and the presence of viral anti-genomic RNAs within egg, second-stage juvenile (J2, and pooled J3 and J4 stages suggests active viral replication within the nematode. Viruses were found at similar or lower levels within field populations of SCN compared with greenhouse cultures of North Carolina populations. Five greenhouse cultures harbored all five known viruses whereas in most populations a mixture of fewer viruses was detected. In contrast, three greenhouse cultures of similar descent to one another did not possess any detectable viruses and primarily differed in location of the cultures (NC versus MO. Several of these SCN viruses were also detected in Heterodera trifolii (clover cyst and Heterodera schachtii (beet cyst, but not the other cyst, root-knot, or reniform nematode species tested. Viruses were not detected within soybean host plant tissue. If nematode infection with viruses is truly more common than first considered, the potential influence on nematode biology, pathogenicity, ecology, and control warrants continued investigation.

  3. High-Resolution Replication Profiles Define the Stochastic Nature of Genome Replication Initiation and Termination

    Directory of Open Access Journals (Sweden)

    Michelle Hawkins

    2013-11-01

    Full Text Available Eukaryotic genome replication is stochastic, and each cell uses a different cohort of replication origins. We demonstrate that interpreting high-resolution Saccharomyces cerevisiae genome replication data with a mathematical model allows quantification of the stochastic nature of genome replication, including the efficiency of each origin and the distribution of termination events. Single-cell measurements support the inferred values for stochastic origin activation time. A strain, in which three origins were inactivated, confirmed that the distribution of termination events is primarily dictated by the stochastic activation time of origins. Cell-to-cell variability in origin activity ensures that termination events are widely distributed across virtually the whole genome. We propose that the heterogeneity in origin usage contributes to genome stability by limiting potentially deleterious events from accumulating at particular loci.

  4. International Expansion through Flexible Replication

    DEFF Research Database (Denmark)

    Jonsson, Anna; Foss, Nicolai Juul

    2011-01-01

    Business organizations may expand internationally by replicating a part of their value chain, such as a sales and marketing format, in other countries. However, little is known regarding how such “international replicators” build a format for replication, or how they can adjust it in order to ada......, etc.) are replicated in a uniform manner across stores, and change only very slowly (if at all) in response to learning (“flexible replication”). We conclude by discussing the factors that influence the approach to replication adopted by an international replicator.......Business organizations may expand internationally by replicating a part of their value chain, such as a sales and marketing format, in other countries. However, little is known regarding how such “international replicators” build a format for replication, or how they can adjust it in order to adapt...

  5. Replication of cultured lung epithelial cells

    International Nuclear Information System (INIS)

    Guzowski, D.; Bienkowski, R.

    1986-01-01

    The authors have investigated the conditions necessary to support replication of lung type 2 epithelial cells in culture. Cells were isolated from mature fetal rabbit lungs (29d gestation) and cultured on feeder layers of mitotically inactivated 3T3 fibroblasts. The epithelial nature of the cells was demonstrated by indirect immunofluorescent staining for keratin and by polyacid dichrome stain. Ultrastructural examination during the first week showed that the cells contained myofilaments, microvilli and lamellar bodies (markers for type 2 cells). The following changes were observed after the first week: increase in cell size; loss of lamellar bodies and appearance of multivesicular bodies; increase in rough endoplasmic reticulum and golgi; increase in tonafilaments and well-defined junctions. General cell morphology was good for up to 10 wk. Cells cultured on plastic surface degenerated after 1 wk. Cell replication was assayed by autoradiography of cultures exposed to ( 3 H)-thymidine and by direct cell counts. The cells did not replicate during the first week; however, between 2-10 wk the cells incorporated the label and went through approximately 6 population doublings. They have demonstrated that lung alveolar epithelial cells can replicate in culture if they are maintained on an appropriate substrate. The coincidence of ability to replicate and loss of markers for differentiation may reflect the dichotomy between growth and differentiation commonly observed in developing systems

  6. The evolutionary ecology of molecular replicators.

    Science.gov (United States)

    Nee, Sean

    2016-08-01

    By reasonable criteria, life on the Earth consists mainly of molecular replicators. These include viruses, transposons, transpovirons, coviruses and many more, with continuous new discoveries like Sputnik Virophage. Their study is inherently multidisciplinary, spanning microbiology, genetics, immunology and evolutionary theory, and the current view is that taking a unified approach has great power and promise. We support this with a new, unified, model of their evolutionary ecology, using contemporary evolutionary theory coupling the Price equation with game theory, studying the consequences of the molecular replicators' promiscuous use of each others' gene products for their natural history and evolutionary ecology. Even at this simple expository level, we can make a firm prediction of a new class of replicators exploiting viruses such as lentiviruses like SIVs, a family which includes HIV: these have been explicitly stated in the primary literature to be non-existent. Closely connected to this departure is the view that multicellular organism immunology is more about the management of chronic infections rather than the elimination of acute ones and new understandings emerging are changing our view of the kind of theatre we ourselves provide for the evolutionary play of molecular replicators. This study adds molecular replicators to bacteria in the emerging field of sociomicrobiology.

  7. Modeling inhomogeneous DNA replication kinetics.

    Directory of Open Access Journals (Sweden)

    Michel G Gauthier

    Full Text Available In eukaryotic organisms, DNA replication is initiated at a series of chromosomal locations called origins, where replication forks are assembled proceeding bidirectionally to replicate the genome. The distribution and firing rate of these origins, in conjunction with the velocity at which forks progress, dictate the program of the replication process. Previous attempts at modeling DNA replication in eukaryotes have focused on cases where the firing rate and the velocity of replication forks are homogeneous, or uniform, across the genome. However, it is now known that there are large variations in origin activity along the genome and variations in fork velocities can also take place. Here, we generalize previous approaches to modeling replication, to allow for arbitrary spatial variation of initiation rates and fork velocities. We derive rate equations for left- and right-moving forks and for replication probability over time that can be solved numerically to obtain the mean-field replication program. This method accurately reproduces the results of DNA replication simulation. We also successfully adapted our approach to the inverse problem of fitting measurements of DNA replication performed on single DNA molecules. Since such measurements are performed on specified portion of the genome, the examined DNA molecules may be replicated by forks that originate either within the studied molecule or outside of it. This problem was solved by using an effective flux of incoming replication forks at the model boundaries to represent the origin activity outside the studied region. Using this approach, we show that reliable inferences can be made about the replication of specific portions of the genome even if the amount of data that can be obtained from single-molecule experiments is generally limited.

  8. Unexpected variation in neuroanatomy among diverse nematode species

    Directory of Open Access Journals (Sweden)

    Ziduan eHan

    2016-01-01

    Full Text Available Nematodes are considered excellent models for understanding fundamental aspects of neuron function. However, nematodes are less frequently used as models for examining the evolution of nervous systems. While the habitats and behaviors of nematodes are diverse, the neuroanatomy of nematodes is often considered highly conserved. A small number of nematode species greatly influences our understanding of nematode neurobiology. The free-living species Caenorhabditis elegans and, to a lesser extent, the mammalian gastrointestinal parasite Ascaris suum are, historically, the primary sources of knowledge regarding nematode neurobiology. Despite differences in size and habitat, C. elegans and Ascaris suum share a surprisingly similar neuroanatomy. Here, we examined species across several clades in the phylum Nematoda and show that there is a surprising degree of neuroanatomical variation both within and among nematode clades when compared to C. elegans and Ascaris. We found variation in the numbers of neurons in the ventral nerve cord and dye-filling pattern of sensory neurons. For example, we found that Pristionchus pacificus, a bacterial feeding species used for comparative developmental research, had 20% fewer ventral cord neurons compared to C. elegans. Steinernema carpocapse, an insect-parasitic nematode capable of jumping behavior, had 40% more ventral cord neurons than C. elegans. Interestingly, the non-jumping congeneric nematode, S. glaseri showed an identical number of ventral cord neurons as S. carpocapsae. There was also variability in the timing of neurodevelopment of the ventral cord with two of five species that hatch as second-stage juveniles showing delayed neurodevelopment. We also found unexpected variation in the dye-filling of sensory neurons among examined species. Again, sensory neuron dye-filling pattern did not strictly correlate with phylogeny. Our results demonstrate that variation in nematode neuroanatomy is more prevalent

  9. Mitochondrial genomes of Meloidogyne chitwoodi and M. incognita (Nematoda: Tylenchina): comparative analysis, gene order and phylogenetic relationships with other nematodes.

    Science.gov (United States)

    Humphreys-Pereira, Danny A; Elling, Axel A

    2014-01-01

    Root-knot nematodes (Meloidogyne spp.) are among the most important plant pathogens. In this study, the mitochondrial (mt) genomes of the root-knot nematodes, M. chitwoodi and M. incognita were sequenced. PCR analyses suggest that both mt genomes are circular, with an estimated size of 19.7 and 18.6-19.1kb, respectively. The mt genomes each contain a large non-coding region with tandem repeats and the control region. The mt gene arrangement of M. chitwoodi and M. incognita is unlike that of other nematodes. Sequence alignments of the two Meloidogyne mt genomes showed three translocations; two in transfer RNAs and one in cox2. Compared with other nematode mt genomes, the gene arrangement of M. chitwoodi and M. incognita was most similar to Pratylenchus vulnus. Phylogenetic analyses (Maximum Likelihood and Bayesian inference) were conducted using 78 complete mt genomes of diverse nematode species. Analyses based on nucleotides and amino acids of the 12 protein-coding mt genes showed strong support for the monophyly of class Chromadorea, but only amino acid-based analyses supported the monophyly of class Enoplea. The suborder Spirurina was not monophyletic in any of the phylogenetic analyses, contradicting the Clade III model, which groups Ascaridomorpha, Spiruromorpha and Oxyuridomorpha based on the small subunit ribosomal RNA gene. Importantly, comparisons of mt gene arrangement and tree-based methods placed Meloidogyne as sister taxa of Pratylenchus, a migratory plant endoparasitic nematode, and not with the sedentary endoparasitic Heterodera. Thus, comparative analyses of mt genomes suggest that sedentary endoparasitism in Meloidogyne and Heterodera is based on convergent evolution. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. SUMO and KSHV Replication

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Pei-Ching [Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan (China); Kung, Hsing-Jien, E-mail: hkung@nhri.org.tw [Institute for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei 110, Taiwan (China); Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616 (United States); UC Davis Cancer Center, University of California, Davis, CA 95616 (United States); Division of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County 35053, Taiwan (China)

    2014-09-29

    Small Ubiquitin-related MOdifier (SUMO) modification was initially identified as a reversible post-translational modification that affects the regulation of diverse cellular processes, including signal transduction, protein trafficking, chromosome segregation, and DNA repair. Increasing evidence suggests that the SUMO system also plays an important role in regulating chromatin organization and transcription. It is thus not surprising that double-stranded DNA viruses, such as Kaposi’s sarcoma-associated herpesvirus (KSHV), have exploited SUMO modification as a means of modulating viral chromatin remodeling during the latent-lytic switch. In addition, SUMO regulation allows the disassembly and assembly of promyelocytic leukemia protein-nuclear bodies (PML-NBs), an intrinsic antiviral host defense, during the viral replication cycle. Overcoming PML-NB-mediated cellular intrinsic immunity is essential to allow the initial transcription and replication of the herpesvirus genome after de novo infection. As a consequence, KSHV has evolved a way as to produce multiple SUMO regulatory viral proteins to modulate the cellular SUMO environment in a dynamic way during its life cycle. Remarkably, KSHV encodes one gene product (K-bZIP) with SUMO-ligase activities and one gene product (K-Rta) that exhibits SUMO-targeting ubiquitin ligase (STUbL) activity. In addition, at least two viral products are sumoylated that have functional importance. Furthermore, sumoylation can be modulated by other viral gene products, such as the viral protein kinase Orf36. Interference with the sumoylation of specific viral targets represents a potential therapeutic strategy when treating KSHV, as well as other oncogenic herpesviruses. Here, we summarize the different ways KSHV exploits and manipulates the cellular SUMO system and explore the multi-faceted functions of SUMO during KSHV’s life cycle and pathogenesis.

  11. DNA Replication Profiling Using Deep Sequencing.

    Science.gov (United States)

    Saayman, Xanita; Ramos-Pérez, Cristina; Brown, Grant W

    2018-01-01

    Profiling of DNA replication during progression through S phase allows a quantitative snap-shot of replication origin usage and DNA replication fork progression. We present a method for using deep sequencing data to profile DNA replication in S. cerevisiae.

  12. Hydroxyurea-Induced Replication Stress

    Directory of Open Access Journals (Sweden)

    Kenza Lahkim Bennani-Belhaj

    2010-01-01

    Full Text Available Bloom's syndrome (BS displays one of the strongest known correlations between chromosomal instability and a high risk of cancer at an early age. BS cells combine a reduced average fork velocity with constitutive endogenous replication stress. However, the response of BS cells to replication stress induced by hydroxyurea (HU, which strongly slows the progression of replication forks, remains unclear due to publication of conflicting results. Using two different cellular models of BS, we showed that BLM deficiency is not associated with sensitivity to HU, in terms of clonogenic survival, DSB generation, and SCE induction. We suggest that surviving BLM-deficient cells are selected on the basis of their ability to deal with an endogenous replication stress induced by replication fork slowing, resulting in insensitivity to HU-induced replication stress.

  13. Trait-mediated diversification in nematode predator–prey systems

    NARCIS (Netherlands)

    Mulder, C.; Helder, J.; Vervoort, M.T.W.; Vonk, J.A.

    2011-01-01

    Nematodes are presumably the most numerous Metazoans in terrestrial habitats. They are represented at all trophic levels and are known to respond to nutrient limitation, prey availability, and microbial resources. Predatory nematodes reside at the highest trophic level, and as such their feeding

  14. A model of nematode dynamics in the Westerschelde estuary

    NARCIS (Netherlands)

    Li, J.; Vincx, M.; Herman, P.M.J.

    1996-01-01

    We developed a time dynamic model to investigate the temporal dynamics of nematode community in the brackish zone of the Westerschelde Estuary. The biomass of four nematode feeding groups observed from March 1991 to February 1992 is used to calibrate the model. Using environmental data as the input,

  15. A Survey of Nematode Infection in Oreochromis niloticus (L ...

    African Journals Online (AJOL)

    The incidence and intensity of nematode infection was investigated in Nile tilapia Oreochromis niloticus from Lake Kyoga, Uganda and 11% of the 406 fish examined were parasitized by nematodes of the genus Contracaecum. The prevalence of these parasites was greatest in the smallest and largest size classes, but this ...

  16. Free-living Marine Nematodes. Part 1 British Enoplids

    African Journals Online (AJOL)

    This is the first of three volumes dealing with the most abundant group of animals on the sea-bed and sea-shore, the free-living marine nematodes, and is devoted to those marine nematodes belonging to the subclass Enoplia. Separate volumes will deal with the orders Chromadorida and. Monhysterida. To most marine ...

  17. 5 Spatial Distribution of Nematodes at Organic.cdr

    African Journals Online (AJOL)

    user

    in organic crop production fields can favour or inhibit nematode build-up. ... that nematode control strategies employed on the organic field might be less effective than expected. ... Method. Study site. Soil samples were collected from an organic vegetable field and a conventional ..... chemical analysis: a practical handbook.

  18. Glutathione peroxidases of the potato cyst nematode Globodera Rostochiensis

    NARCIS (Netherlands)

    Jones, J.T.; Reavy, B.; Smant, G.; Prior, A.E.

    2004-01-01

    We report the cloning and characterisation of full-length DNAs complementary to RNA (cDNAs) encoding two glutathione peroxidases (GpXs) from a plant parasitic nematode, the potato cyst nematode (PCN) Globodera rostochiensis. One protein has a functional signal peptide that targets the protein for

  19. Mapping genetic factors controlling potato - cyst nematode interactions

    NARCIS (Netherlands)

    Rouppe van der Voort, J.N.A.M.

    1998-01-01

    The thesis describes strategies for genetic mapping of the genomes of the potato cyst nematode and potato. Mapping in cyst nematodes was achieved by AFLP genotyping of single cysts and subsequent segregation analysis in a family of sibling populations. The genetic map of Globodera

  20. Cyst nematode-induced changes in plant development

    NARCIS (Netherlands)

    Goverse, A.

    1999-01-01

    This thesis describes a first attempt to investigate the biological activity of cyst nematode secretions on plant cell proliferation and the molecular mechanisms underlying feeding cell development in plant roots upon cyst nematode infection.

    To investigate the role of

  1. Molecular and genetic analyses of potato cyst nematode resistance loci

    NARCIS (Netherlands)

    Bakker, E.H.

    2003-01-01

    This thesis describes the genomic localisation and organisation of loci that harbour resistance to the potato cyst nematode species Globodera pallida and G. rostochiensis . Resistance to the potato cyst nematodes G. pallida and G. rostochiensis is an important aspect in potato breeding. To gain

  2. Nematode community structure as a bioindicator in environmental monitoring

    NARCIS (Netherlands)

    Bongers, T.; Ferris, H.

    1999-01-01

    Four of every five multicellular animals on the planet are nematodes. They occupy any niche that provides an available source of organic carbon in marine, freshwater and terrestrial environments. Nematodes vary in sensitivity to pollutants and environmental disturbance. Recent development of indices

  3. Human Intraocular Filariasis Caused by Pelecitus sp. Nematode, Brazil

    Science.gov (United States)

    Bain, Odile; Diniz, Daniel G.; Nascimento dos Santos, Jeannie; Pinto de Oliveira, Norimar; Frota de Almeida, Izabela Negrão; Frota de Almeida, Rafael Negrão; Frota de Almeida, Luciana Negrão; Dantas-Torres, Filipe; Sobrinho, Edmundo Frota de Almeida

    2011-01-01

    A male nematode was extracted from iris fibers of a man from the Brazilian Amazon region. This nematode belonged to the genus Pelecitus but was distinct from the 16 known species in this genus. Similarities with Pelecitus spp. from neotropical birds suggested an avian origin for this species. PMID:21529397

  4. 75 FR 11111 - Pale Cyst Nematode; Update of Quarantined Areas

    Science.gov (United States)

    2010-03-10

    ...] Pale Cyst Nematode; Update of Quarantined Areas AGENCY: Animal and Plant Health Inspection Service...: Background The pale cyst nematode (PCN, Globodera pallida) is a major pest of potato crops in cool... made changes to the area in the State of Idaho that is quarantined to prevent the spread of pale cyst...

  5. Book review: Systematics of Cyst Nematodes (Nematoda: Heteroderinae)

    Science.gov (United States)

    The cyst nematodes are an important group of plant-parasitic nematodes that cause billions of dollars in economic damage to crops every year. This article reviews a recently published, two-volume monograph that describes the morphological and molecular characteristics of these agriculturally signif...

  6. Transgenic Strategies for Enhancement of Nematode Resistance in Plants

    Directory of Open Access Journals (Sweden)

    Muhammad A. Ali

    2017-05-01

    Full Text Available Plant parasitic nematodes (PPNs are obligate biotrophic parasites causing serious damage and reduction in crop yields. Several economically important genera parasitize various crop plants. The root-knot, root lesion, and cyst nematodes are the three most economically damaging genera of PPNs on crops within the family Heteroderidae. It is very important to devise various management strategies against PPNs in economically important crop plants. Genetic engineering has proven a promising tool for the development of biotic and abiotic stress tolerance in crop plants. Additionally, the genetic engineering leading to transgenic plants harboring nematode resistance genes has demonstrated its significance in the field of plant nematology. Here, we have discussed the use of genetic engineering for the development of nematode resistance in plants. This review article also provides a detailed account of transgenic strategies for the resistance against PPNs. The strategies include natural resistance genes, cloning of proteinase inhibitor coding genes, anti-nematodal proteins and use of RNA interference to suppress nematode effectors. Furthermore, the manipulation of expression levels of genes induced and suppressed by nematodes has also been suggested as an innovative approach for inducing nematode resistance in plants. The information in this article will provide an array of possibilities to engineer resistance against PPNs in different crop plants.

  7. 75 FR 54592 - Pale Cyst Nematode; Update of Quarantined Areas

    Science.gov (United States)

    2010-09-08

    ...] Pale Cyst Nematode; Update of Quarantined Areas AGENCY: Animal and Plant Health Inspection Service... made changes to the area in the State of Idaho that is quarantined to prevent the spread of pale cyst nematode. The description of the quarantined area was updated on April 26, 2010. As a result of these...

  8. Biocontrol of ticks by entomopathogenic nematodes. Research update.

    Science.gov (United States)

    Samish, M; Alekseev, E; Glazer, I

    2000-01-01

    Entomopathogenic nematodes (EPNs) are lethal to ticks even though they do not use their normal propagation cycle within tick cadavers. The tick Boophilus annulatus was found to be far more susceptible to EPNs than Hyalomma excavatum, Rhipicephalus bursa, or Rhipicephalus sanguineus. Ticks seem to be less susceptible to nematodes when feeding on a host. Preimaginal tick stages were less susceptible to nematodes than adult ticks. The mortality rate of unfed females was highest, followed by unfed males, and engorged females. The virulence of nematodes to ticks varied greatly among different nematode strains. In most cases, the Heterorhabditis sp. strains were the most virulent strains tested in petri dishes. In buckets containing sandy soil sprayed with 50 nematodes/cm2 and engorged B. annulatus females, the LT50 of the ticks was less than five days. The addition of manure to soil or a manure extract to petri dishes reduced nematode virulence. Since ticks spend most of their life cycle in the upper humid layer of the ground, and many nematode strains share this same ecological niche, the use of EPNs for biocontrol of ticks appears promising.

  9. Laboratory experiments on the infaunal activity of intertidal nematodes

    NARCIS (Netherlands)

    Steyaert, M.; Moodley, L.; Vanaverbeke, J.; Vandewiele, S.L.; Vincx, M.

    2005-01-01

    The impact of oxygen on the vertical distribution of an intertidal nematode community was investigated in a manipulation experiment with sediments collected from the Oosterschelde (The Netherlands). The vertical distribution of nematodes was examined in response to sediment inversion in perspex

  10. Native nematodes as new bio-insecticides for cranberries

    Science.gov (United States)

    In the summer of 2015, an effort was made in central Wisconsin to find an entomopathogenic nematode capable controlling Wisconsin’s cranberry pests. Using a standard baiting method, a nematode of the Oscheius genus was collected from the mossy, sandy, peat-filled soils of a wild cranberry marsh. Thi...

  11. The cyst nematodes Heterodera and Globodera species in Egypt

    Science.gov (United States)

    Information concerning the occurrence and distribution of the cyst nematodes (Heterodera spp. and Globodera spp.) in Egypt is important to assess their potential to cause economic damage to many crop plants. A nematode survey was conducted in Alexandria, El Behera and Sohag governorates during 2012-...

  12. Screening of in vitro derived mutants of banana against nematodes ...

    African Journals Online (AJOL)

    The rest of the mutants namely Ro Im V4 6-1-2 and Si Im V4 6-2-5 were found to be susceptible to nematodes. The resistant and moderately resistant mutants of banana could be further used in breeding programmes as well as being recognized as potential cultivars of commerce. Key words: Banana, nematode, resistance, ...

  13. Statistical analysis of nematode counts from interlaboratory proficiency tests

    NARCIS (Netherlands)

    Berg, van den W.; Hartsema, O.; Nijs, Den J.M.F.

    2014-01-01

    A series of proficiency tests on potato cyst nematode (PCN; n=29) and free-living stages of Meloidogyne and Pratylenchus (n=23) were investigated to determine the accuracy and precision of the nematode counts and to gain insights into possible trends and potential improvements. In each test, each

  14. Nematode parasitism in adult dairy cows in Belgium

    NARCIS (Netherlands)

    Agneessens, J.; Claerebout, E.; Dorny, P.; Borgsteede, F.H.M.; Vercruysse, J.

    2000-01-01

    Over a period of 1 year, from November 1997 to October 1998, the abomasa, blood and faecal samples of 121 dairy cows in Belgium were collected and examined for nematode infections. Nematodes were present in the abomasa of 110 animals. Ostertagia was found in all 110, Trichostrongylus was seen in 65

  15. DATABASE REPLICATION IN HETEROGENOUS PLATFORM

    OpenAIRE

    Hendro Nindito; Evaristus Didik Madyatmadja; Albert Verasius Dian Sano

    2014-01-01

    The application of diverse database technologies in enterprises today is increasingly a common practice. To provide high availability and survavibality of real-time information, a database replication technology that has capability to replicate databases under heterogenous platforms is required. The purpose of this research is to find the technology with such capability. In this research, the data source is stored in MSSQL database server running on Windows. The data will be replicated to MyS...

  16. Entomogenous nematode Neoaplectana carpocapsae: radiation and mammalian safety

    International Nuclear Information System (INIS)

    Gaugler, R.R.

    1978-01-01

    Infective-stage juveniles of Neoaplacetana carpocapsae were acutely sensitive to short uv radiation (254 nm) and natural sunlight. High nematode mortality, although delayed, accompanied uv exposure. Irradiation rapidly reduced nematode pathogenicity, so that nematodes exposed for 7 min were unable to cause lethal infections in Galleria mallonella larvae. Moreover, the median survival time of Galleria larvae increased progressively as nematode exposure to uv was lengthened. Inhibition of nematode reproduction and development was noted at exposure periods more than 2.45 and 5 min, respectively. However, irradiation did not appear to affect juvenile motility. Exposure to direct sunlight also reduced pathogenicity, in a range from 6.9 to 94.9% at 30 and 60 min of exposure, respectively. Long uv (366 nm) did not affect juveniles at the exposures tested

  17. BASIDIOMYCETE-BASED METHOD FOR BIOCONTROL OF PHYTOPATHOGENIC NEMATODES

    Directory of Open Access Journals (Sweden)

    Tiberius BALAEŞ

    2015-12-01

    Full Text Available Phytopathogenic nematodes represent one of the most important groups of pathogens in crops. The use of chemical to control the nematodes attack in crops is decreasing every year due to the concern of the toxicity and side effects of such compounds. In the course for finding alternatives to the use of chemicals, biological control of nematodes is gaining much attention. Some saprotrophic fungi are able to feed on invertebrates, thus becoming efficient agents of control. In this study, three species of basidiomycetes were analyzed for their potential to be used as control agents of phytopathogenic nematodes. Through on in vitro investigation of these potential, one strain – Gymnopilus junonius was further selected for a pot test against Meloidogyne incognita, a very important phytopathogenic species of nematodes. The fungal treatment strongly decreased the M. incognita population on the tested pots, proving the potential of G. junonius strain to be used in biocontrol.

  18. Survey of nematodes associated with terrestrial slugs in Norway.

    Science.gov (United States)

    Ross, J L; Ivanova, E S; Hatteland, B A; Brurberg, M B; Haukeland, S

    2016-09-01

    A survey of nematodes associated with terrestrial slugs was conducted for the first time in Norway. A total of 611 terrestrial slugs were collected from 32 sample sites. Slugs were identified by means of morphological examination, dissection of genitalia and molecular analysis using mitochondrial DNA. Twelve slug species were identified, representing four different slug families. Internal nematodes were identified by means of morphological analysis and the sequencing of the 18S rRNA gene. Of the sample sites studied, 62.5% were found to be positive for nematode parasites, with 18.7% of all slugs discovered being infected. Five nematode species were identified in this study: Alloionema appendiculatum, Agfa flexilis, Angiostoma limacis, Angiostoma sp. and Phasmarhabditis hermaphrodita. Of these species, only one nematode was previously undescribed (Angiostoma sp.). This is the first record of the presence of A. appendiculatum, A. flexilis and A. limacis in Norway.

  19. Engineered resistance and hypersusceptibility through functional metabolic studies of 100 genes in soybean to its major pathogen, the soybean cyst nematode.

    Science.gov (United States)

    Matthews, Benjamin F; Beard, Hunter; MacDonald, Margaret H; Kabir, Sara; Youssef, Reham M; Hosseini, Parsa; Brewer, Eric

    2013-05-01

    During pathogen attack, the host plant induces genes to ward off the pathogen while the pathogen often produces effector proteins to increase susceptibility of the host. Gene expression studies of syncytia formed in soybean root by soybean cyst nematode (Heterodera glycines) identified many genes altered in expression in resistant and susceptible roots. However, it is difficult to assess the role and impact of these genes on resistance using gene expression patterns alone. We selected 100 soybean genes from published microarray studies and individually overexpressed them in soybean roots to determine their impact on cyst nematode development. Nine genes reduced the number of mature females by more than 50 % when overexpressed, including genes encoding ascorbate peroxidase, β-1,4-endoglucanase, short chain dehydrogenase, lipase, DREPP membrane protein, calmodulin, and three proteins of unknown function. One gene encoding a serine hydroxymethyltransferase decreased the number of mature cyst nematode females by 45 % and is located at the Rhg4 locus. Four genes increased the number of mature cyst nematode females by more than 200 %, while thirteen others increased the number of mature cyst nematode females by more than 150 %. Our data support a role for auxin and ethylene in susceptibility of soybean to cyst nematodes. These studies highlight the contrasting gene sets induced by host and nematode during infection and provide new insights into the interactions between host and pathogen at the molecular level. Overexpression of some of these genes result in a greater decrease in the number of cysts formed than recognized soybean cyst nematode resistance loci.

  20. Identification of novel target genes for safer and more specific control of root-knot nematodes from a pan-genome mining.

    Directory of Open Access Journals (Sweden)

    Etienne G J Danchin

    2013-10-01

    Full Text Available Root-knot nematodes are globally the most aggressive and damaging plant-parasitic nematodes. Chemical nematicides have so far constituted the most efficient control measures against these agricultural pests. Because of their toxicity for the environment and danger for human health, these nematicides have now been banned from use. Consequently, new and more specific control means, safe for the environment and human health, are urgently needed to avoid worldwide proliferation of these devastating plant-parasites. Mining the genomes of root-knot nematodes through an evolutionary and comparative genomics approach, we identified and analyzed 15,952 nematode genes conserved in genomes of plant-damaging species but absent from non target genomes of chordates, plants, annelids, insect pollinators and mollusks. Functional annotation of the corresponding proteins revealed a relative abundance of putative transcription factors in this parasite-specific set compared to whole proteomes of root-knot nematodes. This may point to important and specific regulators of genes involved in parasitism. Because these nematodes are known to secrete effector proteins in planta, essential for parasitism, we searched and identified 993 such effector-like proteins absent from non-target species. Aiming at identifying novel targets for the development of future control methods, we biologically tested the effect of inactivation of the corresponding genes through RNA interference. A total of 15 novel effector-like proteins and one putative transcription factor compatible with the design of siRNAs were present as non-redundant genes and had transcriptional support in the model root-knot nematode Meloidogyne incognita. Infestation assays with siRNA-treated M. incognita on tomato plants showed significant and reproducible reduction of the infestation for 12 of the 16 tested genes compared to control nematodes. These 12 novel genes, showing efficient reduction of parasitism when

  1. A role for α-adducin (ADD-1) in nematode and human memory.

    Science.gov (United States)

    Vukojevic, Vanja; Gschwind, Leo; Vogler, Christian; Demougin, Philippe; de Quervain, Dominique J-F; Papassotiropoulos, Andreas; Stetak, Attila

    2012-03-21

    Identifying molecular mechanisms that underlie learning and memory is one of the major challenges in neuroscience. Taken the advantages of the nematode Caenorhabditis elegans, we investigated α-adducin (add-1) in aversive olfactory associative learning and memory. Loss of add-1 function selectively impaired short- and long-term memory without causing acquisition, sensory, or motor deficits. We showed that α-adducin is required for consolidation of synaptic plasticity, for sustained synaptic increase of AMPA-type glutamate receptor (GLR-1) content and altered GLR-1 turnover dynamics. ADD-1, in a splice-form- and tissue-specific manner, controlled the storage of memories presumably through actin-capping activity. In support of the C. elegans results, genetic variability of the human ADD1 gene was significantly associated with episodic memory performance in healthy young subjects. Finally, human ADD1 expression in nematodes restored loss of C. elegans add-1 gene function. Taken together, our findings support a role for α-adducin in memory from nematodes to humans. Studying the molecular and genetic underpinnings of memory across distinct species may be helpful in the development of novel strategies to treat memory-related diseases.

  2. Multifaceted effects of host plants on entomopathogenic nematodes.

    Science.gov (United States)

    Hazir, Selcuk; Shapiro-Ilan, David I; Hazir, Canan; Leite, Luis G; Cakmak, Ibrahim; Olson, Dawn

    2016-03-01

    The success of parasites can be impacted by multi-trophic interactions. Tritrophic interactions have been observed in parasite-herbivore-host plant systems. Here we investigate aspects of multi-trophic interactions in a system involving an entomopathogenic nematode (EPN), its insect host, and host plant. Novel issues investigated include the impact of tritrophic interactions on nematode foraging behavior, the ability of EPNs to overcome negative tritrophic effects through genetic selection, and interactions with a fourth trophic level (nematode predators). We tested infectivity of the nematode, Steinernema riobrave, to corn earworm larvae (Helicoverpa zea) in three host plants, tobacco, eggplant and tomato. Tobacco reduced nematode virulence and reproduction relative to tomato and eggplant. However, successive selection (5 passages) overcame the deficiency; selected nematodes no longer exhibited reductions in phenotypic traits. Despite the loss in virulence and reproduction nematodes, first passage S. riobrave was more attracted to frass from insects fed tobacco than insects fed on other host plants. Therefore, we hypothesized the reduced virulence and reproduction in S. riobrave infecting tobacco fed insects would be based on a self-medicating tradeoff, such as deterring predation. We tested this hypothesis by assessing predatory success of the mite Sancassania polyphyllae and the springtail Sinella curviseta on nematodes reared on tobacco-fed larvae versus those fed on greater wax moth, Galleria mellonella, tomato fed larvae, or eggplant fed larvae. No advantage was observed in nematodes derived from tobacco fed larvae. In conclusion, our results indicated that insect-host plant diet has an important effect on nematode foraging, infectivity and reproduction. However, negative host plant effects, might be overcome through directed selection. We propose that host plant species should be considered when designing biocontrol programs using EPNs. Copyright © 2016

  3. Identification and functional analysis of secreted effectors from phytoparasitic nematodes.

    Science.gov (United States)

    Rehman, Sajid; Gupta, Vijai K; Goyal, Aakash K

    2016-03-21

    Plant parasitic nematodes develop an intimate and long-term feeding relationship with their host plants. They induce a multi-nucleate feeding site close to the vascular bundle in the roots of their host plant and remain sessile for the rest of their life. Nematode secretions, produced in the oesophageal glands and secreted through a hollow stylet into the host plant cytoplasm, are believed to play key role in pathogenesis. To combat these persistent pathogens, the identity and functional analysis of secreted effectors can serve as a key to devise durable control measures. In this review, we will recapitulate the knowledge over the identification and functional characterization of secreted nematode effector repertoire from phytoparasitic nematodes. Despite considerable efforts, the identity of genes encoding nematode secreted proteins has long been severely hampered because of their microscopic size, long generation time and obligate biotrophic nature. The methodologies such as bioinformatics, protein structure modeling, in situ hybridization microscopy, and protein-protein interaction have been used to identify and to attribute functions to the effectors. In addition, RNA interference (RNAi) has been instrumental to decipher the role of the genes encoding secreted effectors necessary for parasitism and genes attributed to normal development. Recent comparative and functional genomic approaches have accelerated the identification of effectors from phytoparasitic nematodes and offers opportunities to control these pathogens. Plant parasitic nematodes pose a serious threat to global food security of various economically important crops. There is a wealth of genomic and transcriptomic information available on plant parasitic nematodes and comparative genomics has identified many effectors. Bioengineering crops with dsRNA of phytonematode genes can disrupt the life cycle of parasitic nematodes and therefore holds great promise to develop resistant crops against plant

  4. Development of the system nematode, Ditylenchus Dipsaci (Kuehn) Filipjev, and the potato tuber nematode, D. Destructor thore, after gamma irradiation

    International Nuclear Information System (INIS)

    Ignatowicz, S.; Karnkowski, W.

    1996-01-01

    Juvenile and adult nematodes emerged from onion and garlic samples on the 3 rd week after irradiation with doses up to 0.5 kGy and from potato treated with doses up to 2.0 kGy. However, irradiation of onion infected with Ditylenchus dipsaci caused the inhibition of the development and growth of juvenile nematodes to mature forms. Doses of gamma radiation ranging from 0.1 to 0.5 kGy had only a slight effect, if any, on the development and growth of D. dipsaci nematodes infecting garlic, but they increased juvenile mortality. Gamma radiation at doses up to 2.0 kGy induced increased mortality of nematode juveniles of the potato tuber nematode, D. destructor but less so inhibited their development to mature forms. Nematodes were found to be resistant to irradiation treatment. Therefore the use of gamma irradiation for nematode disinfestation of agricultural products seems to be impractical, if the aim of the treatment is to kill these pests within a few weeks. The level of radiation required to kill nematodes in infected plants would damage plant tissues so that the further storage of vegetables will be impossible. (author). 22 refs, 3 figs, 2 tabs

  5. Molecular Diagnostics and Variability of Longidorid Nematodes

    Directory of Open Access Journals (Sweden)

    Francesca De Luca

    2004-08-01

    Full Text Available PCR-RFLP and sequencing approaches of ribosomal DNA are being used to study taxonomy, molecular identification and phylogeny of plant parasitic nematodes. In this paper, we discuss on the usefulness of ITS PCRRFLP analysis to differentiate among longidorid species. In addition, we examined how well ITS PCR-RFLP differentiated between longidorid species, and how well sequencing of two different ribosomal regions, the ITS containing region and D1-D2 domains of the 26S rDNA, were able to infer phylogenetic relationships among those same species. These methods and their advantages in identifying longidorids and establishing their phylogenetic relationships are examined and discussed.

  6. Molecular and Morphological Characterization and Biological Control Capabilities of a Pasteuria ssp. Parasitizing Rotylenchulus reniformis, the Reniform Nematode.

    Science.gov (United States)

    Schmidt, Liesbeth M; Hewlett, Thomas E; Green, April; Simmons, Lee J; Kelley, Karen; Doroh, Mark; Stetina, Salliana R

    2010-09-01

    Rotylenchulus reniformis is one of 10 described species of reniform nematodes and is considered the most economically significant pest within the genus, parasitizing a variety of important agricultural crops. Rotylenchulus reniformis collected from cotton fields in the Southeastern US were observed to have the nematode parasitic bacterium Pasteuria attached to their cuticles. Challenge with a Pasteuria-specific monoclonal antibody in live immuno-fluorescent assay (IFA) confirmed the discovery of Pasteuria infecting R. reniformis. Scanning and transmission electron microscopy were employed to observe endospore ultrastructure and sporogenesis within the host. Pasteuria were observed to infect and complete their life-cycle in juvenile, male and female R. reniformis. Molecular analysis using Pasteuria species-specific and degenerate primers for 16s rRNA and spoII, and subsequent phylogenetic assessment, placed the Pasteuria associated with R. reniformis in a distinct clade within established assemblages for the Pasteuria infecting phytopathogenic nematodes. A global phylogenetic assessment of Pasteuria 16s rDNA using the Neighbor-Joining method resulted in a clear branch with 100% boot-strap support that effectively partitioned the Pasteuria infecting phytopathogenic nematodes from the Pasteuria associated with bacterivorous nematodes. Phylogenetic analysis of the R. reniformis Pasteuria and Pasteuria spp. parasitizing a number of economically important plant parasitic nematodes revealed that Pasteuria with different host specificities are closely related and likely constitute biotypes of the same species. This suggests host preference, and thus effective differentiation and classification are most likely predicated by an influential virulence determinant(s) that has yet to be elucidated. Pasteuria Pr3 endospores produced by in vitro fermentation demonstrated efficacy as a commercial bionematicide to control R. reniformis on cotton in pot tests, when applied as a seed

  7. Mining the secretome of root-knot nematodes for cell wall modifying proteins

    NARCIS (Netherlands)

    Roze, E.H.A.

    2008-01-01

    The products of parasitism genes in nematodes must be secreted to reach their targets at the nematode-plant interface. These nematode secretory proteins are therefore recognised to play an important role in the nematode-plant interaction and as a result have been subject of intense study for years.

  8. [Nematodes (Nematoda) from bats (Chiroptera) of the Samarskaya Luka Peninsula (Russia)].

    Science.gov (United States)

    Kirillova, N Iu; Kirillov, A A; Vekhnik, V P

    2008-01-01

    Fauna of parasitic nematodes from Chiroptera of the Samarskaya Luka has been studied. Seven nematode species has been recorded. Numbers of host specimens, indices of extensiveness and intensiveness of the invasion, parasite abundance, and brief characteristics of the nematode species are given. Some nematode species were for the first time recorded in bats of Russia.

  9. First report of the spiral nematode Helicotylenchus microlobus infecting soybean in North Dakota

    Science.gov (United States)

    Spiral nematodes (Helicotylenchus spp.) are common plant-parasitic nematodes in fields of many crops. In June 2015, two soil samples were collected from a soybean field in Richland County, ND. Nematodes were extracted from soil using the sugar centrifugal flotation method. Plant-parasitic nematodes ...

  10. Efficacy of Trichoderma harzianumT22 as a biocontrol agent against root-knot nematode (Meloidogyne incognita on some soybean varieties

    Directory of Open Access Journals (Sweden)

    T.O. Abiri

    2015-01-01

    Full Text Available In 2012 and 2013, a two-year field study was conducted at the University of Ilorin Teaching and Research Farm, Ilorin, the Southern Guinea Savannah Zone, Nigeria, with the aim to investigate the effect of Trichoderma harzianumT22 as a bio-control agent against a root-knot nematode (Meloidogyne incognita on some soybean varieties. The experimental field, which naturally has been known for the presence of some nematodes such as Pratylenchus, Helicitylenchus, Radopholus, Meloidogyne, Rotylenchulus, Xyphinema, was divided into two blocks, each block consisting of three plots with alleys between blocks and plots measuring 5 m and 1.5 m respectively. All treatments were replicated five times by means of a Randomized Complete Block Design. The initial soil nematode population was increased by chopping six kilograms of Meloidogyne incognita galled roots of Celosia agentea from a pure culture into all the plots. One block was treated with bio-control agent Trichoderma harzianumT22 while the second block served as a control unit. The results show that in terms of plant height, the number of branches, yield and reduction of the soil nematode population and root galls, the plants on the Trichoderma treated plots performed significantly better (P=0.05 than those in the control unit did. This therefore implies that root-knot nematodes represent a major constraint in the production of soybean while Trichoderma harzianumT22 improves the yield growth and the yield of soybean as well as better controls soil nematode populations with respect to the control trials.

  11. Replication of bacteriophage lambda DNA

    International Nuclear Information System (INIS)

    Tsurimoto, T.; Matsubara, K.

    1983-01-01

    In this paper results of studies on the mechanism of bacteriophage lambda replication using molecular biological and biochemical approaches are reported. The purification of the initiator proteins, O and P, and the role of the O and P proteins in the initiation of lambda DNA replication through interactions with specific DNA sequences are described. 47 references, 15 figures

  12. Pattern replication by confined dewetting

    NARCIS (Netherlands)

    Harkema, S.; Schäffer, E.; Morariu, M.D.; Steiner, U

    2003-01-01

    The dewetting of a polymer film in a confined geometry was employed in a pattern-replication process. The instability of dewetting films is pinned by a structured confining surface, thereby replicating its topographic pattern. Depending on the surface energy of the confining surface, two different

  13. Charter School Replication. Policy Guide

    Science.gov (United States)

    Rhim, Lauren Morando

    2009-01-01

    "Replication" is the practice of a single charter school board or management organization opening several more schools that are each based on the same school model. The most rapid strategy to increase the number of new high-quality charter schools available to children is to encourage the replication of existing quality schools. This policy guide…

  14. LHCb experience with LFC replication

    International Nuclear Information System (INIS)

    Bonifazi, F; Carbone, A; D'Apice, A; Dell'Agnello, L; Re, G L; Martelli, B; Ricci, P P; Sapunenko, V; Vitlacil, D; Perez, E D; Duellmann, D; Girone, M; Peco, G; Vagnoni, V

    2008-01-01

    Database replication is a key topic in the framework of the LHC Computing Grid to allow processing of data in a distributed environment. In particular, the LHCb computing model relies on the LHC File Catalog, i.e. a database which stores information about files spread across the GRID, their logical names and the physical locations of all the replicas. The LHCb computing model requires the LFC to be replicated at Tier-1s. The LCG 3D project deals with the database replication issue and provides a replication service based on Oracle Streams technology. This paper describes the deployment of the LHC File Catalog replication to the INFN National Center for Telematics and Informatics (CNAF) and to other LHCb Tier-1 sites. We performed stress tests designed to evaluate any delay in the propagation of the streams and the scalability of the system. The tests show the robustness of the replica implementation with performance going much beyond the LHCb requirements

  15. LHCb experience with LFC replication

    CERN Document Server

    Bonifazi, F; Perez, E D; D'Apice, A; dell'Agnello, L; Düllmann, D; Girone, M; Re, G L; Martelli, B; Peco, G; Ricci, P P; Sapunenko, V; Vagnoni, V; Vitlacil, D

    2008-01-01

    Database replication is a key topic in the framework of the LHC Computing Grid to allow processing of data in a distributed environment. In particular, the LHCb computing model relies on the LHC File Catalog, i.e. a database which stores information about files spread across the GRID, their logical names and the physical locations of all the replicas. The LHCb computing model requires the LFC to be replicated at Tier-1s. The LCG 3D project deals with the database replication issue and provides a replication service based on Oracle Streams technology. This paper describes the deployment of the LHC File Catalog replication to the INFN National Center for Telematics and Informatics (CNAF) and to other LHCb Tier-1 sites. We performed stress tests designed to evaluate any delay in the propagation of the streams and the scalability of the system. The tests show the robustness of the replica implementation with performance going much beyond the LHCb requirements.

  16. Viability Test Device for anisakid nematodes

    Directory of Open Access Journals (Sweden)

    Michael Kroeger

    2018-03-01

    Full Text Available Up to now the visual inspection of mobility of isolated anisakid larvae serves as a measure of viability and possible risk of infection. This paper presents a new method to rule out unreliability – caused by the temporary immobility of the larvae and by the human uncertainty factor of visual observation. By means of a Near infrared (NIR imaging method, elastic curvature energies and geometric shape parameters were determined from contours, and used as a measure of viability. It was based on the modelling of larvae as a cylindrical membrane system. The interaction between curvatures, contraction of the longitudinal muscles, and inner pressure enabled the derivation of viability from stationary form data. From series of spectrally signed images within a narrow wavelength range, curvature data of the larvae were determined. Possible mobility of larvae was taken into account in statistical error variables. Experiments on individual living larvae, long-term observations of Anisakis larvae, and comparative studies of the staining method and the VTD measurements of larvae from the tissue of products confirmed the effectiveness of this method. The VTD differentiated clearly between live and dead nematode larvae isolated from marinated, deep-frozen and salted products. The VTD has been proven as excellent method to detect living anisakid nematode larvae in fishery products and is seen as useful tool for fish processing industry and control authorities. Keywords: Biophysics

  17. Entomopathogenic nematodes in agricultural areas in Brazil.

    Science.gov (United States)

    de Brida, Andressa Lima; Rosa, Juliana Magrinelli Osório; Oliveira, Cláudio Marcelo Gonçalves de; Castro, Bárbara Monteiro de Castro E; Serrão, José Eduardo; Zanuncio, José Cola; Leite, Luis Garrigós; Wilcken, Silvia Renata Siciliano

    2017-04-06

    Entomopathogenic nematodes (EPNs) (Steinernematidae and Heterorhabditidae) can control pests due to the mutualistic association with bacteria that kill the host by septicemia and make the environment favorable for EPNs development and reproduction. The diversity of EPNs in Brazilian soils requires further study. The identification of EPNs, adapted to environmental and climatic conditions of cultivated areas is important for sustainable pest suppression in integrated management programs in agricultural areas of Brazil. The objective was to identify EPNs isolated from agricultural soils with annual, fruit and forest crops in Brazil. Soil samples were collected and stored in 250 ml glass vials. The nematodes were isolated from these samples with live bait traps ([Galleria mellonella L. (Lepidoptera: Pyralidae) larvae]. Infective juveniles were collected with White traps and identified by DNA barcoding procedures by sequencing the D2/D3 expansion of the 28S rDNA region by PCR. EPNs identified in agricultural areas in Brazil were Heterorhabditis amazonensis, Metarhabditis rainai, Oscheios tipulae and Steinernema rarum. These species should be considered pest biocontrol agents in Brazilian agricultural areas.

  18. Arrested larval development in cattle nematodes.

    Science.gov (United States)

    Armour, J; Duncan, M

    1987-06-01

    Most economically important cattle nematodes are able to arrest their larval development within the host - entering a period of dormancy or hypobiosis. Arrested larvae have a low death rate, and large numbers can accumulate in infected cattle during the grazing season. Because of this, outbreaks of disease caused by such nematodes can occur at times when recent infection with the parasites could not have occurred, for example during winter in temperature northern climates when cattle are normally housed. The capacity to arrest is a heritable trait. It is seen as an adaptation by the parasite to avoid further development to its free-living stages during times when the climate is unsuitable for free-living survival. But levels of arrestment can vary markedly in different regions, in different cattle, and under different management regimes. Climatic factors, previous conditioning, host immune status, and farm management all seem to affect arrestment levels. In this article, James Armour and Mary Duncan review the biological basis of the phenomenon, and discuss the apparently conflicting views on how it is controlled.

  19. Effector gene birth in plant parasitic nematodes: Neofunctionalization of a housekeeping glutathione synthetase gene

    Science.gov (United States)

    Lilley, Catherine J.; Maqbool, Abbas; Wu, Duqing; Yusup, Hazijah B.; Jones, Laura M.; Birch, Paul R. J.; Urwin, Peter E.

    2018-01-01

    Plant pathogens and parasites are a major threat to global food security. Plant parasitism has arisen four times independently within the phylum Nematoda, resulting in at least one parasite of every major food crop in the world. Some species within the most economically important order (Tylenchida) secrete proteins termed effectors into their host during infection to re-programme host development and immunity. The precise detail of how nematodes evolve new effectors is not clear. Here we reconstruct the evolutionary history of a novel effector gene family. We show that during the evolution of plant parasitism in the Tylenchida, the housekeeping glutathione synthetase (GS) gene was extensively replicated. New GS paralogues acquired multiple dorsal gland promoter elements, altered spatial expression to the secretory dorsal gland, altered temporal expression to primarily parasitic stages, and gained a signal peptide for secretion. The gene products are delivered into the host plant cell during infection, giving rise to “GS-like effectors”. Remarkably, by solving the structure of GS-like effectors we show that during this process they have also diversified in biochemical activity, and likely represent the founding members of a novel class of GS-like enzyme. Our results demonstrate the re-purposing of an endogenous housekeeping gene to form a family of effectors with modified functions. We anticipate that our discovery will be a blueprint to understand the evolution of other plant-parasitic nematode effectors, and the foundation to uncover a novel enzymatic function. PMID:29641602

  20. Use of organic waste as biofumigant for controlling root knot nematodes (Meloidogyne spp.) on potato

    Science.gov (United States)

    Sari, D. I. P.; Lisnawita; Oemry, S.; Safni, I.; Lubis, K.; Tantawi, A. R.

    2018-02-01

    Root knot nematode (Meloidogyne spp.) is one of the important pathogens that causes big impact on potato crop yields. One of the control strategies for controlling this nematode is the use of biofumigants. Biofumigants are volatile toxic compound derived from plants, and have biocide properties against insects and plant pathogens. Organic waste such as Brassicaceae, Leguminoceae, and Solanaceae can be used as biofumigant sources. This research was conducted to determine the effectiveness of Brassicaceae, Leguminoceae, and Solanaceae as biofumigants against Meloidogyne spp. The experiment was set in a completely randomized design (CRD) with the treatments were organic wastes including Brassicaceae, Leguminoceae, and Solanaceae, both single and combinations, and 2 controls (positive and negative controls) with 3 replications. Each of the biofumigant treatments was prepared and stored for 2 weeks. Potato tubers were transplanted 15 days after germination into polybag inoculated with 1,000 Meloidogyne spp. J2s. The results showed that Brassicaceae + Solanaceae were effective in decreasing the number of galls in potato plants, however only Solanaceae improved plant growth.

  1. Identification of Virulence Factors in Nematode-Trapping Fungi - Insights from Genomics, Transcriptomics and Proteomics

    OpenAIRE

    Andersson, Karl-Magnus

    2013-01-01

    Nematode-trapping fungi are soil-living organisms with the unique ability to capture and infect free-living nematodes. The interest in studying these fungi arises from their potential use as biological control agents for plant- and animal-parasitic nematodes. To enter the parasitic stage, nematode-trapping fungi develop different kinds of trapping structures. In order to understand more about the evolution of parasitism in the nematode-trapping fungi and to identify virulence factors in these...

  2. Changes in soil nematode communities under the impact of fertilizers

    Science.gov (United States)

    Gruzdeva, L. I.; Matveeva, E. M.; Kovalenko, T. E.

    2007-06-01

    Changes taking place in the communities of soil nematodes of an artificially sown meadow under the impact of annually applied mineral fertilizers have been studied in a field experiment for nine years. It is shown that changes in the species composition, trophic structure, and numbers of nematodes from different genera depend on the fertilizer applied and on the competitiveness of the plant species grown. The spectra of nematode genera sensitive to the complete mineral fertilizer (NPK) and to the particular nutrients have been identified with the use of a number of parameters, including the maturity index of nematode communities, the biotope preferences of the particular nematode genera, and the general pattern of nematode habitats. The results obtained in this study can be used to assess the effect of mineral fertilizers on the soil fauna and to suggest optimum application rates of mineral fertilizers ensuring the sustainable development of meadow herbs. The use of the data on the trophic structure of nematode communities for predicting the ways of organic matter decomposition in the soil is discussed.

  3. Novel RNA viruses within plant parasitic cyst nematodes.

    Science.gov (United States)

    Ruark, Casey L; Gardner, Michael; Mitchum, Melissa G; Davis, Eric L; Sit, Tim L

    2018-01-01

    The study of invertebrate-and particularly nematode-viruses is emerging with the advancement of transcriptome sequencing. Five single-stranded RNA viruses have now been confirmed within the economically important soybean cyst nematode (SCN; Heterodera glycines). From previous research, we know these viruses to be widespread in greenhouse and field populations of SCN. Several of the SCN viruses were also confirmed within clover (H. trifolii) and beet (H. schachtii) cyst nematodes. In the presented study, we sequenced the transcriptomes of several inbred SCN populations and identified two previously undiscovered viral-like genomes. Both of these proposed viruses are negative-sense RNA viruses and have been named SCN nyami-like virus (NLV) and SCN bunya-like virus (BLV). Finally, we analyzed publicly available transcriptome data of two potato cyst nematode (PCN) species, Globodera pallida and G. rostochiensis. From these data, a third potential virus was discovered and called PCN picorna-like virus (PLV). PCN PLV is a positive-sense RNA virus, and to the best of our knowledge, is the first virus described within PCN. The presence of these novel viruses was confirmed via qRT-PCR, endpoint PCR, and Sanger sequencing with the exception of PCN PLV due to quarantine restrictions on the nematode host. While much work needs to be done to understand the biological and evolutionary significance of these viruses, they offer insight into nematode ecology and the possibility of novel nematode management strategies.

  4. Reciprocal Interactions between Nematodes and Their Microbial Environments.

    Science.gov (United States)

    Midha, Ankur; Schlosser, Josephine; Hartmann, Susanne

    2017-01-01

    Parasitic nematode infections are widespread in nature, affecting humans as well as wild, companion, and livestock animals. Most parasitic nematodes inhabit the intestines of their hosts living in close contact with the intestinal microbiota. Many species also have tissue migratory life stages in the absence of severe systemic inflammation of the host. Despite the close coexistence of helminths with numerous microbes, little is known concerning these interactions. While the environmental niche is considerably different, the free-living nematode Caenorhabditis elegans ( C. elegans ) is also found amongst a diverse microbiota, albeit on decaying organic matter. As a very well characterized model organism that has been intensively studied for several decades, C. elegans interactions with bacteria are much more deeply understood than those of their parasitic counterparts. The enormous breadth of understanding achieved by the C. elegans research community continues to inform many aspects of nematode parasitology. Here, we summarize what is known regarding parasitic nematode-bacterial interactions while comparing and contrasting this with information from work in C. elegans . This review highlights findings concerning responses to bacterial stimuli, antimicrobial peptides, and the reciprocal influences between nematodes and their environmental bacteria. Furthermore, the microbiota of nematodes as well as alterations in the intestinal microbiota of mammalian hosts by helminth infections are discussed.

  5. Unraveling flp-11/flp-32 dichotomy in nematodes.

    Science.gov (United States)

    Atkinson, Louise E; Miskelly, Iain R; Moffett, Christy L; McCoy, Ciaran J; Maule, Aaron G; Marks, Nikki J; Mousley, Angela

    2016-10-01

    FMRFamide-like peptide (FLP) signalling systems are core to nematode neuromuscular function. Novel drug discovery efforts associated with nematode FLP/FLP receptor biology are advanced through the accumulation of basic biological data that can reveal subtle complexities within the neuropeptidergic system. This study reports the characterisation of FMRFamide-like peptide encoding gene-11 (flp-11) and FMRFamide-like peptide encoding gene-32 (flp-32), two distinct flp genes which encode the analogous peptide, AMRN(A/S)LVRFamide, in multiple nematode species - the only known example of this phenomenon within the FLPergic system of nematodes. Using bioinformatics, in situ hybridisation, immunocytochemistry and behavioural assays we show that: (i) flp-11 and -32 are distinct flp genes expressed individually or in tandem across multiple nematode species, where they encode a highly similar peptide; (ii) flp-11 does not appear to be the most widely expressed flp in Caenorhabditis elegans; (iii) in species expressing both flp-11 and flp-32, flp-11 displays a conserved, restricted expression pattern across nematode clades and lifestyles; (iv) in species expressing both flp-11 and flp-32, flp-32 expression is more widespread and less conserved than flp-11; (v) in species expressing only flp-11, the flp-11 expression profile is more similar to the flp-32 profile observed in species expressing both; and (vi) FLP-11 peptides inhibit motor function in multiple nematode species. The biological significance and evolutionary origin of flp-11 and -32 peptide duplication remains unclear despite attempts to identify a common ancestor; this may become clearer as the availability of genomic data improves. This work provides insight into the complexity of the neuropeptidergic system in nematodes, and begins to examine how nematodes may compensate for structural neuronal simplicity. From a parasite control standpoint, this work underscores the importance of basic biological data, and has

  6. NACSA Charter School Replication Guide: The Spectrum of Replication Options. Authorizing Matters. Replication Brief 1

    Science.gov (United States)

    O'Neill, Paul

    2010-01-01

    One of the most important and high-profile issues in public education reform today is the replication of successful public charter school programs. With more than 5,000 failing public schools in the United States, there is a tremendous need for strong alternatives for parents and students. Replicating successful charter school models is an…

  7. Genetic analysis of resistance to ticks, gastrointestinal nematodes and Eimeria spp. in Nellore cattle.

    Science.gov (United States)

    Passafaro, Tiago Luciano; Carrera, Juan Pablo Botero; dos Santos, Livia Loiola; Raidan, Fernanda Santos Silva; dos Santos, Dalinne Chrystian Carvalho; Cardoso, Eduardo Penteado; Leite, Romário Cerqueira; Toral, Fabio Luiz Buranelo

    2015-06-15

    The aim of the present study was to obtain genetic parameters for resistance to ticks, gastrointestinal nematodes (worms) and Eimeria spp. in Nellore cattle, analyze the inclusion of resistance traits in Nellore breeding programs and evaluate genetic selection as a complementary tool in parasite control programs. Counting of ticks, gastrointestinal nematode eggs and Eimeria spp. oocysts per gram of feces totaling 4270; 3872 and 3872 records from 1188; 1142 and 1142 animals, respectively, aged 146 to 597 days were used. The animals were classified as resistant (counts equal to zero) or susceptible (counts above zero) to each parasite. The statistical models included systematics effects of contemporary groups and the mean trajectory. The random effects included additive genetic effects, direct permanent environmental effects and residual. The mean trajectory and random effects were modeled with linear Legendre polynomials for all traits except for the mean trajectory of resistance to Eimeria spp., which employed the cubic polynomial. Heritability estimates were of low to moderate magnitude and ranged from 0.06 to 0.30, 0.06 to 0.33 and 0.04 to 0.33 for resistance to ticks, gastrointestinal nematodes and Eimeria spp., respectively. The posterior mean of genetic and environmental correlations for the same trait at different ages (205, 365, 450 and 550 days) were favorable at adjacent ages and unfavorable at distant ages. In general, the posterior mean of the genetic and environmental correlations between traits of resistance were low and high-density intervals were large and included zero in many cases. The heritability estimates support the inclusion of resistance to ticks, gastrointestinal nematodes and Eimeria spp. in Nellore breeding programs. Genetic selection can increase the frequency of resistant animals and be used as a complementary tool in parasite control programs. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Plant nematodes in South Africa. 11. Checklist of plant nematodes of the protected areas of KwaZulu-Natal

    Directory of Open Access Journals (Sweden)

    Mariette Marais

    2013-03-01

    Full Text Available Nematodes are some of the most abundant soil organisms and are an essential part of soil ecology. These organisms are used as indicator organisms and can be linked to soil health. Biological collections contain vast amounts of data, with the National Collection of Nematodes housed at the Plant Protection Research Institute, Agricultural Research Council being no different. During the digitising of the collection a number of unpublished records of plant nematodes reported from protected areas in KwaZulu-Natal were found in the South African Plant-Parasitic Nematode Survey database. A total of 222 plant nematode species belonging to 39 genera were reported from the province, with only 94 of these species reported from the protected areas and 172 and 159 species reported from uncultivated (outside the protected areas and cultivated areas, respectively. Only nine species, Criconema silvum, Criconema talanum, Helicotylenchus marethae, Ogma dracomontanum, Ogma louisi, Ogma ueckermanni, Paralongidorus deborae, Trichodorus rinae and Xiphinemella marindae were described from protected areas, whilst O. dracomontanum, P. deborae and T. rinae were subsequently also reported from other provinces. Conservation implications: A higher degree of diversity of nematodes was observed in the unprotected areas of the province. The observation suggests that nematode fauna, and by implication also other invertebrates, are not adequately protected.

  9. Plant nematodes in South Africa. 11. Checklist of plant nematodes of the protected areas of KwaZulu-Natal

    Directory of Open Access Journals (Sweden)

    Mariette Marais

    2013-02-01

    Full Text Available Nematodes are some of the most abundant soil organisms and are an essential part of soil ecology. These organisms are used as indicator organisms and can be linked to soil health. Biological collections contain vast amounts of data, with the National Collection of Nematodes housed at the Plant Protection Research Institute, Agricultural Research Council being no different. During the digitising of the collection a number of unpublished records of plant nematodes reported from protected areas in KwaZulu-Natal were found in the South African Plant-Parasitic Nematode Survey database. A total of 222 plant nematode species belonging to 39 genera were reported from the province, with only 94 of these species reported from the protected areas and 172 and 159 species reported from uncultivated (outside the protected areas and cultivated areas, respectively. Only nine species, Criconema silvum, Criconema talanum, Helicotylenchus marethae, Ogma dracomontanum, Ogma louisi, Ogma ueckermanni, Paralongidorus deborae, Trichodorus rinae and Xiphinemella marindae were described from protected areas, whilst O. dracomontanum, P. deborae and T. rinae were subsequently also reported from other provinces. Conservation implications: A higher degree of diversity of nematodes was observed in the unprotected areas of the province. The observation suggests that nematode fauna, and by implication also other invertebrates, are not adequately protected.

  10. Cereal Cyst Nematode (Heterodera avenae) on Oats. II. Early Root Development and Nematode Tolerance

    OpenAIRE

    Volkmar, K. M.

    1989-01-01

    The effect of Heterodera avenae infestation on early seminal and lateral root growth was examined in four oat genotypes differing in tolerance to H. avenae. Recently emerged seminal roots were inoculated with a range of H. avenae larval densities, then transferred a hydroponic system to remove the effect of later nematode penetration on root development. Intolerance to H. avenae was assessed in terms of impairment of seminal root extension resulting in fewer primary lateral roots emerging fro...

  11. Condensed tannins act against cattle nematodes

    DEFF Research Database (Denmark)

    Novobilský, Adam; Mueller-Harvey, Irene; Thamsborg, Stig Milan

    2011-01-01

    The use of natural plant anthelmintics was suggested as a possible alternative control of gastrointestinal nematodes (GIN) in ruminants. Direct anthelmintic effects of tannin-containing plants have already been shown in sheep and goat GIN. These anthelmintic properties are mainly associated...... with condensed tannins. In the present study, we evaluated possible in vitro effects of three tannin-containing plants against bovine GIN. Effects of Onobrychis viciifolia, Lotus pedunculatus and Lotus corniculatus condensed tannin (CT) extracts on Cooperia oncophora and Ostertagia ostertagi were determined...... (third stage larvae) was also affected by CT extracts from all three plants. In both in vitro assays, extracts with added polyvinylpolypyrrolidone, an inhibitor of tannins, generated almost the same values as the negative control; this confirms the role of CT in the anthelmintic effect of these plant...

  12. Prevalence of common gastro-intestinal nematode infections in ...

    African Journals Online (AJOL)

    ACSS

    (GIN) infection and identified the common GIN parasites in commercial goat production in. Central Uganda. .... Table 1. Prevalence of gastro-intestinal nematode parasites in goats in Central Uganda .... ILCA, Addis Ababa, Ethiopia. pp. 40-76.

  13. Integrated management of root-knot nematode (Meloidogyne ...

    African Journals Online (AJOL)

    Integrated management of root-knot nematode (Meloidogyne incognita) for tomato production and productivity. Bayuh Belay1* ... important food and cash crop of the farmers and is ...... some part of the research budget without any reservation.

  14. Anisakid nematodes associated with aquatic orga- nisms and ...

    African Journals Online (AJOL)

    spamer

    and respond to long- and medium-term physical, chemical and biological .... that the formation of fibrotic capsules around nematode larvae might prevent further ... capabilities and function primarily in the encapsulation of large parasitic ...

  15. Infection Assay of Cyst Nematodes on Arabidopsis Roots.

    Science.gov (United States)

    Bohlmann, Holger; Wieczorek, Krzysztof

    2015-09-20

    Plant parasitic nematodes are devastating pests on many crops. Juveniles (J2) of cyst nematodes invade the roots to induce a syncytium. This feeding site is their only source of nutrients. Male nematodes leave the roots after the fourth molt to mate with females. The females stay attached to their syncytia throughout their life and produce hundreds of eggs, which are contained in their bodies. When the females die their bodies form the cysts, which protect the eggs. Cysts can survive for many years in the soil until favorable conditions induce hatching of the juveniles. The beet cyst nematode Heterodera schachtii ( H. schachtii )is a pathogen of sugar beet ( Beta vulgaris ) but can also complete its life cycle on Arabidopsis roots growing on agar plates under sterile conditions. We present here protocols for a stock culture of H. schachtii and an infection assay on agar plates.

  16. Systemic induced tolerance against root-knot nematodes in rice

    African Journals Online (AJOL)

    user

    Rice plantlets were randomly grown in laboratory, sprayed with hormones and riboflavin .... between riboflavin, SA, JA and ET pathways in rice-nematodes interaction, ..... oxidative damage caused by aging as well as biotic and abiotic stress.

  17. DNA replication in ultraviolet light irradiated Chinese hamster cells: the nature of replicon inhibition and post-replication repair

    International Nuclear Information System (INIS)

    Doniger, J.

    1978-01-01

    DNA replication in ultraviolet light irradiated Chinese hamster cells was studied using techniques of DNA fiber autoradiography and alkaline sucrose sedimentation. Bidirectionally growing replicons were observed in the autoradiograms independent of the irradiation conditions. After a dose of 5 J/m 2 at 254 nm the rate of fork progression was the same as in unirradiated cells, while the rate of replication was reduced by 50%. After a dose of 10J/m 2 the rate of fork progression was reduced 40%, while the replication rate was only 25% of normal. Therefore, at low doses of ultraviolet light irradiation, the inhibition of DNA replication is due to reduction in the number of functioning replicons, while at higher doses the rate of fork progression is also slowed. Those replicons which no longer function after irradiation are blocked in fork movement rather than replicon initiation. After irradiation, pulse label was first incorporated into short nascent strands, the average size of which was approximately equal to the distance between pyrimidine dimers. Under conditions where post-replication repair occurs these short strands were eventually joined into larger pieces. Finally, the data show that slowing post-replication repair with caffeine does not slow fork movement. The results presented here support the post-replication repair model of 'gapped synthesis' and rule out a major role for 'replicative bypass'. (author)

  18. Cell lines that support replication of a novel herpes simplex virus 1 UL31 deletion mutant can properly target UL34 protein to the nuclear rim in the absence of UL31

    International Nuclear Information System (INIS)

    Liang Li; Tanaka, Michiko; Kawaguchi, Yasushi; Baines, Joel D.

    2004-01-01

    Previous results indicated that the herpes simplex virus 1 (HSV-1) U L 31 gene is necessary and sufficient for localization of the U L 34 protein exclusively to the nuclear membrane of infected Hep2 cells. In the current studies, a bacterial artificial chromosome containing the entire HSV-1 strain F genome was used to construct a recombinant viral genome in which a gene encoding kanamycin resistance was inserted in place of 262 codons of the 306 codon U L 31 open reading frame. The deletion virus produced virus titers approximately 10- to 50-fold lower in rabbit skin cells, more than 2000-fold lower in Vero cells, and more than 1500-fold lower in CV1 cells, compared to a virus bearing a restored U L 31 gene. The replication of the U L 31 deletion virus was restored on U L 31-complementing cell lines derived either from rabbit skin cells or CV1 cells. Confocal microscopy indicated that the majority of U L 34 protein localized aberrantly in the cytoplasm and nucleoplasm of Vero cells and CV1 cells, whereas U L 34 protein localized at the nuclear membrane in rabbit skin cells, and U L 31 complementing CV1 cells infected with the U L 31 deletion virus. We conclude that rabbit skin cells encode a function that allows proper localization of U L 34 protein to the nuclear membrane. We speculate that this function partially complements that of U L 31 and may explain why U L 31 is less critical for replication in rabbit skin cells as opposed to Vero and CV1 cells

  19. Challenges for mass production of nematodes in submerged culture.

    Science.gov (United States)

    de la Torre, Mayra

    2003-08-01

    Nematodes of Steinernema and Heterorhabditis genera are used as agents in insect biocontrol programs. They are associated with specific bacteria which are also involved in the mechanism of pathogenicity and which are consumed by nematodes as living food. S. feltiae has various developmental stages in its life cycle, including four juvenile stages, adults and the free living form. During mating, males coil themselves around the female, which is around 1 cm long. Successful commercialization of nematode-bacteria biocontrol products depends on the ability to produce sufficient quantities of these products at competitive prices for a full pest control program. This could be feasible if high cell density submerged cultures are designed and implemented; however, major problems related to nematodes mass production in a bioreactor remain unsolved due to the lack of knowledge about the physiological aspects of the nematode, bacteria and nematode-bacteria association, interaction between the three phases present in the bioreactor (liquid, gas, nematodes-bacteria), possibility of mating under hydrodynamic stress conditions, etc. We have found that the two most important engineering aspects to take into account the mass propagation of nematodes are oxygen transfer rate and hydrodynamics to allow mating and to avoid mechanical damage of juveniles in stage 2. This article focuses on several aspects related to the fermentation system such as kinetics of growth, shear stress, hydrodynamics fields in the bioreactor and oxygen demand. Also, results published by other groups, together with those of our own, will be discussed in relation to the main challenges found during the fermentation process.

  20. Biocontrol: Bacillus penetrans and Related Parasites of Nematodes

    OpenAIRE

    Sayre, R. M.

    1980-01-01

    Bacillus penetrans Mankau, 1975, previously described as Duboscqia penetrans Thorne 1940, is a candidate agent for biocontrol of nematodes. This review considers the life stages of this bacterium: vegetative growth phase, colony fragmentation, sporogenesis, soil phase, spore attachment, and penetration into larvae of root-knot nematodes. The morphology of the microthallus colonies and the unusual external features of the spore are discussed. Taxonomic affinities with the actinomycetes, partic...

  1. Nematodes from terrestrial and freshwater habitats in the Arctic

    Science.gov (United States)

    2014-01-01

    Abstract We present an updated list of terrestrial and freshwater nematodes from all regions of the Arctic, for which records of properly identified nematode species are available: Svalbard, Jan Mayen, Iceland, Greenland, Nunavut, Northwest territories, Alaska, Lena River estuary, Taymyr and Severnaya Zemlya and Novaya Zemlya. The list includes 391 species belonging to 146 genera, 54 families and 10 orders of the phylum Nematoda. PMID:25197239

  2. Targeted mutagenesis in a human-parasitic nematode

    Science.gov (United States)

    Gang, Spencer S.; Castelletto, Michelle L.

    2017-01-01

    Parasitic nematodes infect over 1 billion people worldwide and cause some of the most common neglected tropical diseases. Despite their prevalence, our understanding of the biology of parasitic nematodes has been limited by the lack of tools for genetic intervention. In particular, it has not yet been possible to generate targeted gene disruptions and mutant phenotypes in any parasitic nematode. Here, we report the development of a method for introducing CRISPR-Cas9-mediated gene disruptions in the human-parasitic threadworm Strongyloides stercoralis. We disrupted the S. stercoralis twitchin gene unc-22, resulting in nematodes with severe motility defects. Ss-unc-22 mutations were resolved by homology-directed repair when a repair template was provided. Omission of a repair template resulted in deletions at the target locus. Ss-unc-22 mutations were heritable; we passed Ss-unc-22 mutants through a host and successfully recovered mutant progeny. Using a similar approach, we also disrupted the unc-22 gene of the rat-parasitic nematode Strongyloides ratti. Our results demonstrate the applicability of CRISPR-Cas9 to parasitic nematodes, and thereby enable future studies of gene function in these medically relevant but previously genetically intractable parasites. PMID:29016680

  3. Relationship between production, nematodes and "redness" in strawberries

    Directory of Open Access Journals (Sweden)

    Paula Nogueira Curi

    2016-08-01

    Full Text Available ABSTRACT: In recent years "redness" has increasingly appeared in strawberry plants with leaves taking on a reddish color. No causal agent has been associated with plants. Since strawberries presented problems due to the incidence of nematodes, the purpose of this study was to look at the relationship between production, resistance to the Meloidogyne hapla nematode and the "redness" symptom in strawberry cultivars. Two experiments were performed, both with the 'Camino Real', 'Festival', 'Oso Grande', 'Albion' and 'Camarosa' cultivars. The first experiment was performed in the field, where the following were evaluated: strawberry production, fruit quality, macro and micronutrient contents in fruit and leaves, percentage of plant survival, incidence of nematodes, quantity of eggs in the roots and juveniles in the soil, and the incidence of Botrytis cinerea . In the second experiment, the strawberries were transplanted into pots and filled with pinus bark-based commercial substrate. Half the pots were inocculated with Meloidogyne hapla . Cultivars presented differences in fruit production and also in the incidence of "redness". Lowest performance in production was related to the high incidence of the nematode Meloidogyne hapla. 'Oso Grande' and 'Albion' presented nematode-resistant behavior. It was possible find a relationship between the incidence of the Meloidogyne hapla nematode, and the incidence of "redness" only 'Camino Real' cultivar.

  4. Communities of terrestrial nematodes after different approaches to heathland restoration

    Science.gov (United States)

    Radochova, Petra; Frouz, Jan

    2016-04-01

    Since the 20th century, the distribution of European heathlands rapidly decreased due to agricultural intensification, heavy use of artificial fertilizers or acidification (Aerts & Heil, 1993). Therefore, various attempts of heathland restoration are under way in these days. Analysis of nematode community composition can be one of the tools suitable for succession evaluation (Ferris et al., 2001). In 2011, 2013 and 2014, soil samples were collected from heathland restoration experiment (launched in 2011) where different restoration methods were applied in a 3 × 3 factorial experiment; existing heathlands were also sampled to identify the target community both in dry and wet heathland. A total of 60 samples of extracted nematodes were analysed for absolute abundance, trophic groups, and genera dominance. Various indices were calculated to describe the nematode community. We were able to prove faster development of wet heathlands towards the target community. However, because of large data variability, there was no significant difference between treatments. Development of wet and dry heathlands differed also in increased proportion of omniphagous nematodes in 2013 and predators in 2014 in dry heathlands. After three years of heathland restoration, nematode community has not yet reached parameters of the target community. References Aerts, R., Heil, G. W., 1993. Heathlands: patterns and processes in a changing environment, 1st ed, Geobotany: 20. Springer Netherlands, Dordrecht, p. 229. Ferris, H., Bongers, T., De Goede, R. G. M., 2001. A framework for soil food web diagnostics: Extension of the nematode faunal analysis oncept. Appl. Soil Ecol. 18, 13-29.

  5. Discovery of genomic intervals that underlie nematode responses to benzimidazoles.

    Science.gov (United States)

    Zamanian, Mostafa; Cook, Daniel E; Zdraljevic, Stefan; Brady, Shannon C; Lee, Daehan; Lee, Junho; Andersen, Erik C

    2018-03-01

    Parasitic nematodes impose a debilitating health and economic burden across much of the world. Nematode resistance to anthelmintic drugs threatens parasite control efforts in both human and veterinary medicine. Despite this threat, the genetic landscape of potential resistance mechanisms to these critical drugs remains largely unexplored. Here, we exploit natural variation in the model nematodes Caenorhabditis elegans and Caenorhabditis briggsae to discover quantitative trait loci (QTL) that control sensitivity to benzimidazoles widely used in human and animal medicine. High-throughput phenotyping of albendazole, fenbendazole, mebendazole, and thiabendazole responses in panels of recombinant lines led to the discovery of over 15 QTL in C. elegans and four QTL in C. briggsae associated with divergent responses to these anthelmintics. Many of these QTL are conserved across benzimidazole derivatives, but others show drug and dose specificity. We used near-isogenic lines to recapitulate and narrow the C. elegans albendazole QTL of largest effect and identified candidate variants correlated with the resistance phenotype. These QTL do not overlap with known benzimidazole target resistance genes from parasitic nematodes and present specific new leads for the discovery of novel mechanisms of nematode benzimidazole resistance. Analyses of orthologous genes reveal conservation of candidate benzimidazole resistance genes in medically important parasitic nematodes. These data provide a basis for extending these approaches to other anthelmintic drug classes and a pathway towards validating new markers for anthelmintic resistance that can be deployed to improve parasite disease control.

  6. Characterization of Bacteria Associated with Pinewood Nematode Bursaphelenchus xylophilus

    Science.gov (United States)

    Vicente, Claudia S. L.; Nascimento, Francisco; Espada, Margarida; Barbosa, Pedro; Mota, Manuel; Glick, Bernard R.; Oliveira, Solange

    2012-01-01

    Pine wilt disease (PWD) is a complex disease integrating three major agents: the pathogenic agent, the pinewood nematode Bursaphelenchus xylophilus; the insect-vector Monochamus spp.; and the host pine tree, Pinus sp. Since the early 80's, the notion that another pathogenic agent, namely bacteria, may play a role in PWD has been gaining traction, however the role of bacteria in PWD is still unknown. The present work supports the possibility that some B. xylophilus-associated bacteria may play a significant role in the development of this disease. This is inferred as a consequence of: (i) the phenotypic characterization of a collection of 35 isolates of B. xylophilus-associated bacteria, in different tests broadly used to test plant pathogenic and plant growth promoting bacteria, and (ii) greenhouse experiments that infer the pathogenicity of these bacteria in maritime pine, Pinus pinaster. The results illustrate the presence of a heterogeneous microbial community associated with B. xylophilus and the traits exhibited by at least, some of these bacteria, appear to be related to PWD symptoms. The inoculation of four specific B. xylophilus-associated bacteria isolates in P. pinaster seedlings resulted in the development of some PWD symptoms suggesting that these bacteria likely play an active role with B. xylophilus in PWD. PMID:23091599

  7. REPLICATION TOOL AND METHOD OF PROVIDING A REPLICATION TOOL

    DEFF Research Database (Denmark)

    2016-01-01

    The invention relates to a replication tool (1, 1a, 1b) for producing a part (4) with a microscale textured replica surface (5a, 5b, 5c, 5d). The replication tool (1, 1a, 1b) comprises a tool surface (2a, 2b) defining a general shape of the item. The tool surface (2a, 2b) comprises a microscale...... energy directors on flange portions thereof uses the replication tool (1, 1a, 1b) to form an item (4) with a general shape as defined by the tool surface (2a, 2b). The formed item (4) comprises a microscale textured replica surface (5a, 5b, 5c, 5d) with a lateral arrangement of polydisperse microscale...

  8. Tomato transgenic plants expressing hairpin construct of a nematode protease gene conferred enhanced resistance to root-knot nematodes

    Directory of Open Access Journals (Sweden)

    Tushar Kanti Dutta

    2015-04-01

    Full Text Available Root-knot nematodes (Meloidogyne incognita cause substantial yield losses in vegetables worldwide, and are difficult to manage. Continuous withdrawal of environmentally-harmful nematicides from the global market warrants the need for novel nematode management strategies. Utility of host-delivered RNAi has been demonstrated in several plants (Arabidopsis, tobacco and soybean that exhibited resistance against root-knot and cyst nematodes. Herein, a M. incognita-specific protease gene, cathepsin L cysteine proteinase (Mi-cpl-1, was targeted to generate tomato transgenic lines to evaluate the genetically modified nematode resistance. In vitro knockdown of Mi-cpl-1 gene led to the reduced attraction and penetration of M. incognita in tomato, suggesting the involvement of Mi-cpl-1 in nematode parasitism. Transgenic expression of the RNAi construct of Mi-cpl-1 gene resulted in 60-80% reduction in infection and multiplication of M. incognita in tomato. Evidence for in vitro and in vivo silencing of Mi-cpl-1 was confirmed by expression analysis using quantitative PCR. Our study demonstrates that Mi-cpl-1 plays crucial role during plant-nematode interaction and plant-mediated downregulation of this gene elicits detrimental effect on M. incognita development, reinforcing the potential of RNAi technology for management of phytonematodes in crop plants.

  9. Pathogenicity of Two Species of Entomopathogenic Nematodes Against the Greenhouse Whitefly, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae), in Laboratory and Greenhouse Experiments.

    Science.gov (United States)

    Rezaei, Nastaran; Karimi, Javad; Hosseini, Mojtaba; Goldani, Morteza; Campos-Herrera, Raquel

    2015-03-01

    The greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) is a polyphagous pest in greenhouse crops. The efficacy of two entomopathogenic nematodes (EPN), Steinernema feltiae and Heterorhabditis bacteriophora, as biological control agents against T. vaporariorum was evaluated using two model crops typical of vegetable greenhouse productions: cucumber and pepper. Laboratory tests evaluated adults and second nymphal instars for pest susceptibility to different EPN species at different concentrations of infective juveniles (IJ; 0, 25, 50, 100, 150, 200, and 250 IJ per cm(2)); subsequent greenhouse trials against second nymphal instars on cucumber and pepper plants evaluated more natural conditions. Concentrations were applied in combination with Triton X-100 (0.1% v/v), an adjuvant for increasing nematode activity. In laboratory studies, both life stages were susceptible to infection by the two nematode species, but S. feltiae recorded a lower LC50 than H. bacteriophora for both insect stages. Similarly, in greenhouse experiments, S. feltiae required lower concentrations of IJ than H. bacteriophora to reach the same mortality in nymphs. In greenhouse trials, a significant difference was observed in the triple interaction among nematode species × concentration × plant. Furthermore, the highest mortality rate of the second nymphal instars of the T. vaporariorum was obtained from the application of S. feltiae concentrated to 250 IJ/cm(2) on cucumber (49 ± 1.23%). The general mortality caused by nematodes was significantly higher in cucumber than in pepper. These promising results support further investigation for the optimization of the best EPN species/concentration in combination with insecticides or adjuvants to reach a profitable control of this greenhouse pest.

  10. Autonomous replication of plasmids bearing monkey DNA origin-enriched sequences

    International Nuclear Information System (INIS)

    Frappier, L.; Zannis-Hadjopoulos, M.

    1987-01-01

    Twelve clones of origin-enriched sequences (ORS) isolated from early replicating monkey (CV-1) DNA were examined for transient episomal replication in transfected CV-1, COS-7, and HeLa cells. Plasmid DNA was isolated at time intervals after transfection and screened by the Dpn I resistance assay or by the bromodeoxyuridine substitution assay to differentiate between input and replicated DNA. The authors have identified four monkey ORS (ORS3, -8, -9, and -12) that can support plasmid replication in mammalian cells. This replication is carried out in a controlled and semiconservative manner characteristic of mammalian replicons. ORS replication was most efficient in HeLa cells. Electron microscopy showed ORS8 and ORS12 plasmids of the correct size with replication bubbles. Using a unique restriction site in ORS12, we have mapped the replication bubble within the monkey DNA sequence

  11. Path analyses of the influence of substrate composition on nematode numbers and on decomposition of stranded seaweed at an Antarctic coast

    Science.gov (United States)

    Alkemade, R.; Van Rijswijk, P.

    Large amounts of seaweed are deposited along the coast of Admiralty Bay, King George Island, Antarctica. The stranded seaweed partly decomposes on the beach and supports populations of meiofauna species, mostly nematodes. The factors determining the number of nematodes found in the seaweed packages were studied. Seaweed/sediment samples were collected from different locations, along the coast near Arctowski station, covering gradients of salinity, elevation and proximity of Penguin rookeries. On the same locations decomposition rate was determined by means of permeable containers with seaweed material. Models, including the relations between location, seaweed and sediment characteristics, number of nematodes and decomposition rates, were postulated and verified using path analysis. The most plausible and significant models are presented. The number of nematodes was directly correlated with the height of the location, the carbon-to-nitrogen ratio, and the salinity of the sample. Nematode numbers were apparently indirectly dependent on sediment composition and water content. We hypothesize that the different influences of melt water and tidal water, which affect both salinity and water content of the deposits, are important phenomena underlying these results. Analysis of the relation between decomposition rate and abiotic, location-related characteristics showed that decomposition rate was dependent on the water content of the stranded seaweed and sediment composition. Decomposition rates were high on locations where water content of the deposits was high. There the running water from melt water run-off or from the surf probably increased weight losses of seaweed.

  12. Nematode 18S rRNA gene is a reliable tool for environmental biosafety assessment of transgenic banana in confined field trials.

    Science.gov (United States)

    Nakacwa, R; Kiggundu, A; Talwana, H; Namaganda, J; Lilley, C; Tushemereirwe, W; Atkinson, H

    2013-10-01

    Information on relatedness in nematodes is commonly obtained by DNA sequencing of the ribosomal internal transcribed spacer region. However, the level of diversity at this locus is often insufficient for reliable species differentiation. Recent findings suggest that the sequences of a fragment of the small subunit nuclear ribosomal DNA (18S rRNA or SSU), identify genera of soil nematodes and can also distinguish between species in some cases. A database of soil nematode genera in a Ugandan soil was developed using 18S rRNA sequences of individual nematodes from a GM banana confined field trial site at the National Agricultural Research Laboratories, Kawanda in Uganda. The trial was planted to evaluate transgenic bananas for resistance to black Sigatoka disease. Search for relatedness of the sequences gained with entries in a public genomic database identified a range of 20 different genera and sometimes distinguished species. Molecular markers were designed from the sequence information to underpin nematode faunal analysis. This approach provides bio-indicators for disturbance of the soil environment and the condition of the soil food web. It is being developed to support environmental biosafety analysis by detecting any perturbance by transgenic banana or other GM crops on the soil environment.

  13. RNA-Seq reveals the molecular mechanism of trapping and killing of root-knot nematodes by nematode-trapping fungi.

    Science.gov (United States)

    Pandit, Ramesh; Patel, Reena; Patel, Namrata; Bhatt, Vaibhav; Joshi, Chaitanya; Singh, Pawan Kumar; Kunjadia, Anju

    2017-04-01

    Nematode-trapping fungi are well known for their inherent potential to trap and kill nematodes using specialized trapping devices. However, the molecular mechanisms underlying the trapping and subsequent processes are still unclear. Therefore, in this study, we examined differential genes expression in two nematode-trapping fungi after baiting with nematode extracts. In Arthrobotrys conoides, 809 transcripts associated with diverse functions such as signal transduction, morphogenesis, stress response and peroxisomal proteins, proteases, chitinases and genes involved in the host-pathogen interaction showed differential expression with fold change (>±1.5 fold) in the presence of nematode extract with FDR (p-value nematode-trapping fungi for its host. The findings illustrate the molecular mechanism of fungal parasitism in A. conoides which may be helpful in developing a potential biocontrol agent against parasitic nematodes.

  14. Nematode assemblages in the rhizosphere of spring barley (Hordeum vulgare L.) depended on fertilisation and plant growth phase

    DEFF Research Database (Denmark)

    Madsen, Mette Vestergård

    2004-01-01

    rhizosphere; nitrogen and phosphorus fertilisation; nematode assemblages; plant parasites; barley......rhizosphere; nitrogen and phosphorus fertilisation; nematode assemblages; plant parasites; barley...

  15. Biomarkers of replicative senescence revisited

    DEFF Research Database (Denmark)

    Nehlin, Jan

    2016-01-01

    Biomarkers of replicative senescence can be defined as those ultrastructural and physiological variations as well as molecules whose changes in expression, activity or function correlate with aging, as a result of the gradual exhaustion of replicative potential and a state of permanent cell cycle...... arrest. The biomarkers that characterize the path to an irreversible state of cell cycle arrest due to proliferative exhaustion may also be shared by other forms of senescence-inducing mechanisms. Validation of senescence markers is crucial in circumstances where quiescence or temporary growth arrest may...... be triggered or is thought to be induced. Pre-senescence biomarkers are also important to consider as their presence indicate that induction of aging processes is taking place. The bona fide pathway leading to replicative senescence that has been extensively characterized is a consequence of gradual reduction...

  16. Regulation of beta cell replication

    DEFF Research Database (Denmark)

    Lee, Ying C; Nielsen, Jens Høiriis

    2008-01-01

    Beta cell mass, at any given time, is governed by cell differentiation, neogenesis, increased or decreased cell size (cell hypertrophy or atrophy), cell death (apoptosis), and beta cell proliferation. Nutrients, hormones and growth factors coupled with their signalling intermediates have been...... suggested to play a role in beta cell mass regulation. In addition, genetic mouse model studies have indicated that cyclins and cyclin-dependent kinases that determine cell cycle progression are involved in beta cell replication, and more recently, menin in association with cyclin-dependent kinase...... inhibitors has been demonstrated to be important in beta cell growth. In this review, we consider and highlight some aspects of cell cycle regulation in relation to beta cell replication. The role of cell cycle regulation in beta cell replication is mostly from studies in rodent models, but whether...

  17. Origin, distribution and 3D-modeling of Gr-EXPB1, an expansin from the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Kudla, Urszula; Qin, Ling; Milac, Adina; Kielak, Anna; Maissen, Cyril; Overmars, Hein; Popeijus, Herman; Roze, Erwin; Petrescu, Andrei; Smant, Geert; Bakker, Jaap; Helder, Johannes

    2005-04-25

    Southern analysis showed that Gr-EXPB1, a functional expansin from the potato cyst nematode Globodera rostochiensis, is member of a multigene family, and EST data suggest expansins to be present in other plant parasitic nematodes as well. Homology modeling predicted that Gr-EXPB1 domain 1 (D1) has a flat beta-barrel structure with surface-exposed aromatic rings, whereas the 3D structure of Gr-EXPB1-D2 was remarkably similar to plant expansins. Gr-EXPB1 shows highest sequence similarity to two extracellular proteins from saprophytic soil-inhabiting Actinobacteria, and includes a bacterial type II carbohydrate-binding module. These results support the hypothesis that a number of pathogenicity factors of cyst nematodes is of procaryotic origin and were acquired by horizontal gene transfer.

  18. Personality and Academic Motivation: Replication, Extension, and Replication

    Science.gov (United States)

    Jones, Martin H.; McMichael, Stephanie N.

    2015-01-01

    Previous work examines the relationships between personality traits and intrinsic/extrinsic motivation. We replicate and extend previous work to examine how personality may relate to achievement goals, efficacious beliefs, and mindset about intelligence. Approximately 200 undergraduates responded to the survey with a 150 participants replicating…

  19. Rolling replication of UV-irradiated duplex DNA in the phi X174 replicative-form----single-strand replication system in vitro

    International Nuclear Information System (INIS)

    Shavitt, O.; Livneh, Z.

    1989-01-01

    Cloning of the phi X174 viral origin of replication into phage M13mp8 produced an M13-phi X174 chimera, the DNA of which directed efficient replicative-form----single-strand rolling replication in vitro. This replication assay was performed with purified phi X174-encoded gene A protein, Escherichia coli rep helicase, single-stranded DNA-binding protein, and DNA polymerase III holoenzyme. The nicking of replicative-form I (RFI) DNA by gene A protein was essentially unaffected by the presence of UV lesions in the DNA. However, unwinding of UV-irradiated DNA by the rep helicase was inhibited twofold as compared with unwinding of the unirradiated substrate. UV irradiation of the substrate DNA caused a strong inhibition in its ability to direct DNA synthesis. However, even DNA preparations that contained as many as 10 photodimers per molecule still supported the synthesis of progeny full-length single-stranded DNA. The appearance of full-length radiolabeled products implied at least two full rounds of replication, since the first round released the unlabeled plus viral strand of the duplex DNA. Pretreatment of the UV-irradiated DNA substrate with purified pyrimidine dimer endonuclease from Micrococcus luteus, which converted photodimer-containing supercoiled RFI DNA into relaxed, nicked RFII DNA and thus prevented its replication, reduced DNA synthesis by 70%. Analysis of radiolabeled replication products by agarose gel electrophoresis followed by autoradiography revealed that this decrease was due to a reduction in the synthesis of progeny full-length single-stranded DNA. This implies that 70 to 80% of the full-length DNA products produced in this system were synthesized on molecules that carried photodimers

  20. Observations on nematodes from the Indonesian shortfin eel Anguilla bicolor bicolor McClelland in India, including a revalidation of Heliconema ahiri Karve, 1941 (Physalopteridae)

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Sheeba, S.; Kumar, A. B.

    2013-01-01

    Roč. 58, č. 4 (2013), s. 496-503 ISSN 1230-2821 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:60077344 Keywords : Parasitic nematode * Heliconema * Procamallanus * Spirocamallanus * freshwater eel * Anguilla bicolor bicolor * Kerala * India Subject RIV: EA - Cell Biology Impact factor: 0.965, year: 2013

  1. New nematode species, Orientatractis mekongensis n. sp. (Atractidae) and Neosynodontisia suratthaniensis n. g., n. sp. (Pharyngodonidae) from freshwater fishes in Thailand

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Kamchoo, K.; Pachanawan, A.

    2015-01-01

    Roč. 92, č. 3 (2015), s. 197-209 ISSN 0165-5752 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:60077344 Keywords : parasitic nematode * Pharyngodonidae * Thailand Subject RIV: EG - Zoology Impact factor: 1.316, year: 2015

  2. Dentirumai philippinensis n. gen., n. sp (Nematoda: Philometridae), a new tissue-infecting philometrid nematode from the loach goby Rhyacichthys aspro (Valenciennes) (Rhyacichthyidae) in the Philippines

    Czech Academy of Sciences Publication Activity Database

    Quiazon, K.M.A.; Moravec, František

    2013-01-01

    Roč. 87, č. 1 (2013), s. 59-65 ISSN 0022-149X R&D Projects: GA MŠk LC522 Institutional support: RVO:60077344 Keywords : Philometridae * Phillipine Archipelago * Parasitic nematode Subject RIV: EA - Cell Biology Impact factor: 1.303, year: 2013

  3. Redescription of Heliconema africanum (Linstow, 1899) n. comb. (Nematoda: Physalopteridae), a nematode parasite of freshwater eels (Anguilla spp.) in South Africa

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Taraschewski, H.; Weyl, O.L.F.

    2013-01-01

    Roč. 85, č. 3 (2013), s. 263-269 ISSN 0165-5752 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:60077344 Keywords : Parasitic nematode * Heliconema * South Africa Subject RIV: EA - Cell Biology Impact factor: 1.035, year: 2013

  4. Nematodes parasites de quatre especes de Carangoides (Osteichthyes: Carangidae) des eaux de Nouvelle-Caledonie, avec description de Philometra dispar n. sp. (Philometridae)

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Gey, D.; Justine, J.-L.

    2016-01-01

    Roč. 23, Sep 12 (2016), č. článku 40. ISSN 1252-607X R&D Projects: GA ČR(CZ) GBP505/12/G112 Institutional support: RVO:60077344 Keywords : parasitic nematode * new species * marine fish * New Caledonia * South Pacific Subject RIV: EG - Zoology Impact factor: 2.545, year: 2016

  5. The Effect of Solarization and Manure in Controlling Sugar Beet Cyst Nematode Heterodera schachtii Schmidt

    Directory of Open Access Journals (Sweden)

    mehdi Nasr Esfahani

    2017-01-01

    Full Text Available Introduction. Sugar beet cyst nematode, Heterodera schachtii Schmidt is the major disease of sugar beet worldwide, causing considerable damages, and even death of the plants, in the infested fields. There are several suggested methods of controls, which may have its own difficulties to be taken into consideration. To avoid the use of nematicides, and reduced the risk of chemical hazards in the environment, any sorts of nonchemical management is incorrigible. However, any method of management must be safe, large scale application and economical. Thus, in this manuscript, polyethylene sheaths were used to solarize and or disinfection of the infested soils to H. schachtii. And, also, the incorporation of the farm yards manure was taken into consideration too. Therefore, the field experiments were carried out in infected sugar beet growing regions, where there was a heavy infestation to the sugar beet nematodes, Isfahan province, Iran, to determine the effects of soil solarization alone and or along with undecomposed farm yard manure on sugar beet cyst nematode, H. schachtii. Material and Methods. Transparent Polyethylene sheaths of 2microns were used to solarize and or disinfection of the infested soils to H. schachtii. The fresh farm yards manure for 40 tons per hector for the incorporation was taken into consideration. The field experiments were carried out in infected sugar beet growing regions, where, there was a heavy infestation to the sugar beet nematodes, Jey and Ghahab of Isfahan, Isfahan province, Iran, for determination of the effects of soil solarization alone and or along with undecomposed farm yard manure on sugar beet cyst nematode, H. schachtii. Treatments were consisted of soil solarization with transparent polyethylene sheets, fresh yard manure, integration of soil solarization with farm yard manure and untreated, control and or ckecks in a randomized block design in three replications each in an infested field conditions, in the

  6. A Transactional Asynchronous Replication Scheme for Mobile Database Systems

    Institute of Scientific and Technical Information of China (English)

    丁治明; 孟小峰; 王珊

    2002-01-01

    In mobile database systems, mobility of users has a significant impact on data replication. As a result, the various replica control protocols that exist today in traditional distributed and multidatabase environments are no longer suitable. To solve this problem, a new mobile database replication scheme, the Transaction-Level Result-Set Propagation (TLRSP)model, is put forward in this paper. The conflict detection and resolution strategy based on TLRSP is discussed in detail, and the implementation algorithm is proposed. In order to compare the performance of the TLRSP model with that of other mobile replication schemes, we have developed a detailed simulation model. Experimental results show that the TLRSP model provides an efficient support for replicated mobile database systems by reducing reprocessing overhead and maintaining database consistency.

  7. The entomopathogenic nematode Heterorhabditis megidis: host searching behaviour, infectivity and reproduction

    NARCIS (Netherlands)

    Boff, M.I.C.

    2001-01-01

    Entomopathogenic nematodes in the families Heterorhabditidae and Steinernematidae have considerable potential as biological control agents of soil-inhabiting insect pests. Attributes making these nematodes ideal biological control agents include their broad host range, high virulence,

  8. Characterization of soil nematode communities in three cropping systems through morphological and DNA metabarcoding approaches

    Science.gov (United States)

    Communities of soil nematodes impact ecosystem functions, including plant growth, decomposition, and nutrient cycling, all of which are vital processes in agriculture. We used complementary morphological and DNA metabarcoding analyses to characterize soil nematode communities in three cropping syste...

  9. Plant and soil nematodes from Lokchao Yangoupokpi Wildlife Sanctuary, Manipur, India

    OpenAIRE

    N. Mohilal; M. Pramodini; L. Bina

    2009-01-01

    In the present study soil samples were collected from Lokchao Yangoupokpi Wildlife Sanctuary to investigate about what nematode species are associated with different plant hosts. This study shows rich nematode diversity in the sanctuary.

  10. Plant and soil nematodes from Lokchao Yangoupokpi Wildlife Sanctuary, Manipur, India

    Directory of Open Access Journals (Sweden)

    N. Mohilal

    2009-03-01

    Full Text Available In the present study soil samples were collected from Lokchao Yangoupokpi Wildlife Sanctuary to investigate about what nematode species are associated with different plant hosts. This study shows rich nematode diversity in the sanctuary.

  11. The dual effects of root-cap exudates on nematodes: from quiescence in plant-parasitic nematodes to frenzy in entomopathogenic nematodes.

    Science.gov (United States)

    Hiltpold, Ivan; Jaffuel, Geoffrey; Turlings, Ted C J

    2015-02-01

    To defend themselves against herbivores and pathogens, plants produce numerous secondary metabolites, either constitutively or de novo in response to attacks. An intriguing constitutive example is the exudate produced by certain root-cap cells that can induce a state of reversible quiescence in plant-parasitic nematodes, thereby providing protection against these antagonists. The effect of such root exudates on beneficial entomopathogenic nematodes (EPNs) remains unclear, but could potentially impair their use in pest management programmes. We therefore tested how the exudates secreted by green pea (Pisum sativum) root caps affect four commercial EPN species. The exudates induced reversible quiescence in all EPN species tested. Quiescence levels varied with the green pea cultivars tested. Notably, after storage in root exudate, EPN performance traits were maintained over time, whereas performances of EPNs stored in water rapidly declined. In sharp contrast to high concentrations, lower concentrations of the exudate resulted in a significant increase in EPN activity and infectiousness, but still reduced the activity of two plant-parasitic nematode species. Our study suggests a finely tuned dual bioactivity of the exudate from green pea root caps. Appropriately formulated, it can favour long-term storage of EPNs and boost their infectiousness, while it may also be used to protect plants from plant-parasitic nematodes. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  12. Chameleon Chasing II: A Replication.

    Science.gov (United States)

    Newsom, Doug A.; And Others

    1993-01-01

    Replicates a 1972 survey of students, educators, and Public Relations Society of America members regarding who the public relations counselor really serves. Finds that, in 1992, most respondents thought primary responsibility was to the client, then to the client's relevant publics, then to self, then to society, and finally to media. Compares…

  13. Hyperthermia stimulates HIV-1 replication.

    Directory of Open Access Journals (Sweden)

    Ferdinand Roesch

    Full Text Available HIV-infected individuals may experience fever episodes. Fever is an elevation of the body temperature accompanied by inflammation. It is usually beneficial for the host through enhancement of immunological defenses. In cultures, transient non-physiological heat shock (42-45°C and Heat Shock Proteins (HSPs modulate HIV-1 replication, through poorly defined mechanisms. The effect of physiological hyperthermia (38-40°C on HIV-1 infection has not been extensively investigated. Here, we show that culturing primary CD4+ T lymphocytes and cell lines at a fever-like temperature (39.5°C increased the efficiency of HIV-1 replication by 2 to 7 fold. Hyperthermia did not facilitate viral entry nor reverse transcription, but increased Tat transactivation of the LTR viral promoter. Hyperthermia also boosted HIV-1 reactivation in a model of latently-infected cells. By imaging HIV-1 transcription, we further show that Hsp90 co-localized with actively transcribing provirus, and this phenomenon was enhanced at 39.5°C. The Hsp90 inhibitor 17-AAG abrogated the increase of HIV-1 replication in hyperthermic cells. Altogether, our results indicate that fever may directly stimulate HIV-1 replication, in a process involving Hsp90 and facilitation of Tat-mediated LTR activity.

  14. Adressing Replication and Model Uncertainty

    DEFF Research Database (Denmark)

    Ebersberger, Bernd; Galia, Fabrice; Laursen, Keld

    innovation survey data for France, Germany and the UK, we conduct a ‘large-scale’ replication using the Bayesian averaging approach of classical estimators. Our method tests a wide range of determinants of innovation suggested in the prior literature, and establishes a robust set of findings on the variables...

  15. Replication of kinetoplast minicircle DNA

    International Nuclear Information System (INIS)

    Sheline, C.T.

    1989-01-01

    These studies describe the isolation and characterization of early minicircle replication intermediates from Crithidia fasciculata, and Leishmania tarentolae, the mitochondrial localization of a type II topoisomerase (TIImt) in C. fasciculata, and the implication of the aforementioned TIImt in minicircle replication in L. tarentolae. Early minicircle replication intermediates from C. fasciculata were identified and characterized using isolated kinetoplasts to incorporate radiolabeled nucleotides into its DNA. The pulse-label in an apparent theta-type intermediate chase into two daughter molecules. A uniquely gapped, ribonucleotide primed, knotted molecule represents the leading strand in the model proposed, and a highly gapped molecule represents the lagging strand. This theta intermediate is repaired in vitro to a doubly nicked catenated dimer which was shown to result from the replication of a single parental molecule. Very similar intermediates were found in the heterogeneous population of minicircles of L. tarentolae. The sites of the Leishmania specific discontinuities were mapped and shown to lie within the universally conserved sequence blocks in identical positions as compared to C. fasciculata and Trypanosoma equiperdum

  16. Survival and Movement of Insect Parasitic Nematodes in Poultry Manure and Their Infectivity Against Musca domestica

    OpenAIRE

    Georgis, Ramon; Mullens, Bradley A.; Meyer, Jeffery A.

    1987-01-01

    Survival, infectivity, and movement of three insect parasitic nematodes (Steinernema feltiae All strain, S. bibionis SN strain, and Heterorhabditis heliothidis NC strain) in poultry manure were tested under laboratory conditions. The majority (70-100%) of the nematodes died within 18 hours after exposure to the manure. Nematodes exposed to manure slurry for 6 hours killed at least 95% of the house fly larvae, Musca domestica, but nematodes exposed for 12 hours achieved less than 40% larval mo...

  17. Glutathione peroxidases of the potato cyst nematode Globodera Rostochiensis.

    Science.gov (United States)

    Jones, J T; Reavy, B; Smant, G; Prior, A E

    2004-01-07

    We report the cloning and characterisation of full-length DNAs complementary to RNA (cDNAs) encoding two glutathione peroxidases (GpXs) from a plant parasitic nematode, the potato cyst nematode (PCN) Globodera rostochiensis. One protein has a functional signal peptide that targets the protein for secretion from animal cells while the other is predicted to be intracellular. Both genes are expressed in all parasite stages tested. The mRNA encoding the intracellular GpX is present throughout the nematode second stage juvenile and is particularly abundant in metabolically active tissues including the genital primordia. The mRNA encoding the secreted GpX is restricted to the hypodermis, the outermost cellular layer of the nematode, a location from which it is likely to be secreted to the parasite surface. Biochemical studies confirmed the secreted protein as a functional GpX and showed that, like secreted GpXs of other parasitic nematodes, it does not metabolise hydrogen peroxide but has a preference for larger hydroperoxide substrates. The intracellular protein is likely to have a role in metabolism of active oxygen species derived from internal body metabolism while the secreted protein may protect the parasite from host defences. Other functional roles for this protein are discussed.

  18. The FMRFamide-like peptide family in nematodes

    Directory of Open Access Journals (Sweden)

    Katleen ePeymen

    2014-06-01

    Full Text Available In the three decades since the FMRFamide peptide was isolated from the mollusk Macrocallista nimbosa, structurally similar peptides sharing a C-terminal RFamide motif have been identified across the animal kingdom. FMRFamide-like peptides (FLPs represent the largest known family of neuropeptides in invertebrates. In the phylum Nematoda, at least 32 flp genes are classified, making the FLP system of nematodes unusually complex. The diversity of the nematode FLP complement is most extensively mapped in Caenorhabditis elegans, where over 70 FLPs have been predicted. FLPs have shown to be expressed in the majority of the 302 C. elegans neurons including interneurons, sensory and motor neurons. The vast expression of FLPs is reflected in the broad functional repertoire of nematode FLP signaling, including neuroendocrine and neuromodulatory effects on locomotory activity, reproduction, feeding, and behavior. In contrast to the many identified nematode FLPs, only few peptides have been assigned a receptor and there is the need to clarify the pathway components and working mechanisms of the FLP signaling network. Here, we review the diversity, distribution, and functions of FLPs in nematodes.

  19. Smart Parasitic Nematodes Use Multifaceted Strategies to Parasitize Plants

    Directory of Open Access Journals (Sweden)

    Muhammad A. Ali

    2017-10-01

    Full Text Available Nematodes are omnipresent in nature including many species which are parasitic to plants and cause enormous economic losses in various crops. During the process of parasitism, sedentary phytonematodes use their stylet to secrete effector proteins into the plant cells to induce the development of specialized feeding structures. These effectors are used by the nematodes to develop compatible interactions with plants, partly by mimicking the expression of host genes. Intensive research is going on to investigate the molecular function of these effector proteins in the plants. In this review, we have summarized which physiological and molecular changes occur when endoparasitic nematodes invade the plant roots and how they develop a successful interaction with plants using the effector proteins. We have also mentioned the host genes which are induced by the nematodes for a compatible interaction. Additionally, we discuss how nematodes modulate the reactive oxygen species (ROS and RNA silencing pathways in addition to post-translational modifications in their own favor for successful parasitism in plants.

  20. Variation in the susceptibility of Drosophila to different entomopathogenic nematodes.

    Science.gov (United States)

    Peña, Jennifer M; Carrillo, Mayra A; Hallem, Elissa A

    2015-03-01

    Entomopathogenic nematodes (EPNs) in the genera Heterorhabditis and Steinernema are lethal parasites of insects that are of interest as models for understanding parasite-host interactions and as biocontrol agents for insect pests. EPNs harbor a bacterial endosymbiont in their gut that assists in insect killing. EPNs are capable of infecting and killing a wide range of insects, yet how the nematodes and their bacterial endosymbionts interact with the insect immune system is poorly understood. Here, we develop a versatile model system for understanding the insect immune response to parasitic nematode infection that consists of seven species of EPNs as model parasites and five species of Drosophila fruit flies as model hosts. We show that the EPN Steinernema carpocapsae, which is widely used for insect control, is capable of infecting and killing D. melanogaster larvae. S. carpocapsae is associated with the bacterium Xenorhabdus nematophila, and we show that X. nematophila induces expression of a subset of antimicrobial peptide genes and suppresses the melanization response to the nematode. We further show that EPNs vary in their virulence toward D. melanogaster and that Drosophila species vary in their susceptibilities to EPN infection. Differences in virulence among different EPN-host combinations result from differences in both rates of infection and rates of postinfection survival. Our results establish a powerful model system for understanding mechanisms of host-parasite interactions and the insect immune response to parasitic nematode infection. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  1. Crinivirus replication and host interactions

    Directory of Open Access Journals (Sweden)

    Zsofia A Kiss

    2013-05-01

    Full Text Available Criniviruses comprise one of the genera within the family Closteroviridae. Members in this family are restricted to the phloem and rely on whitefly vectors of the genera Bemisia and/or Trialeurodes for plant-to-plant transmission. All criniviruses have bipartite, positive-sense ssRNA genomes, although there is an unconfirmed report of one having a tripartite genome. Lettuce infectious yellows virus (LIYV is the type species of the genus, the best studied so far of the criniviruses and the first for which a reverse genetics system was available. LIYV RNA 1 encodes for proteins predicted to be involved in replication, and alone is competent for replication in protoplasts. Replication results in accumulation of cytoplasmic vesiculated membranous structures which are characteristic of most studied members of the Closteroviridae. These membranous structures, often referred to as BYV-type vesicles, are likely sites of RNA replication. LIYV RNA 2 is replicated in trans when co-infecting cells with RNA 1, but is temporally delayed relative to RNA1. Efficient RNA 2 replication also is dependent on the RNA 1-encoded RNA binding protein, P34. No LIYV RNA 2-encoded proteins have been shown to affect RNA replication, but at least four, CP, CPm, Hsp70h, and p59 are virion structural components and CPm is a determinant of whitefly transmissibility. Roles of other LIYV RNA 2-encoded proteins are largely as yet unknown, but P26 is a non-virion protein that accumulates in cells as characteristic plasmalemma deposits which in plants are localized within phloem parenchyma and companion cells over plasmodesmata connections to sieve elements. The two remaining crinivirus-conserved RNA 2-encoded proteins are P5 and P9. P5 is 39 amino acid protein and is encoded at the 5’ end of RNA 2 as ORF1 and is part of the hallmark closterovirus gene array. The orthologous gene in BYV has been shown to play a role in cell-to-cell movement and indicated to be localized to the

  2. Prevalence of Pasteuria SP. on Renfirom Nematode in a Georgia Cotton Field

    Science.gov (United States)

    Pasteuria species are bacterial parasites of nematodes and have been associated with suppression of root-knot, sting, and cyst nematode populations. Little is known about the Pasteuria sp. infecting the reniform nematode. While sampling a cotton field study near Cochran, GA, we found Pasteuria spo...

  3. Regulatory interplay between soybean root and soybean cyst nematode during a resistant and susceptible reaction

    Science.gov (United States)

    Background: Plant parasitic nematodes (PPNs) are obligate parasites that feed on the roots of living host plants. Often, these nematodes can lay hundreds of eggs, each capable of surviving in the soil for as long as 12 years. When it comes to wreaking havoc on agricultural yield, few nematodes can c...

  4. 78 FR 27856 - Golden Nematode; Removal of Regulated Areas in Livingston and Steuben Counties, NY

    Science.gov (United States)

    2013-05-13

    .... APHIS-2012-0079] Golden Nematode; Removal of Regulated Areas in Livingston and Steuben Counties, NY... nematode regulations by removing areas in Livingston and Steuben Counties in New York from the list of... nematode, and we determined that regulation of these areas was no longer necessary. As a result of that...

  5. 7 CFR 301.85-9 - Movement of live golden nematodes.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Movement of live golden nematodes. 301.85-9 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Golden Nematode Quarantine and Regulations § 301.85-9 Movement of live golden nematodes. Regulations requiring a permit for and otherwise...

  6. 78 FR 1713 - Golden Nematode; Removal of Regulated Areas in Livingston and Steuben Counties, NY

    Science.gov (United States)

    2013-01-09

    ...-0079] Golden Nematode; Removal of Regulated Areas in Livingston and Steuben Counties, NY AGENCY: Animal... are amending the golden nematode regulations by removing areas in Livingston and Steuben Counties in... areas in these two counties are free of golden nematode, and we have determined that regulation of these...

  7. A SNARE-like protein and biotin are implicated in soybean cyst nematode virulence

    Science.gov (United States)

    Some phytoparasitic nematodes have the ability to infect and reproduce on plants that are normally considered resistant to nematode infection. Such nematodes are referred to as virulent and the mechanisms they use to evade or suppress host plant defenses are not well understood. Here, we report the ...

  8. EVALUATION OF TRICHODERMA SPP. ON BEAN CULTURE, IN ANTHRACNOSE, WEB BLIGHT AND ROOT-KNOT NEMATODE

    Directory of Open Access Journals (Sweden)

    P. E. V. Aguiar

    2014-09-01

    Full Text Available Mato Grosso is the third largest producer of bean from Brazil, being the third harvest (irrigated the most productive, but diseases such as anthracnose, web blight and nematodes of galls cause losses to producers. In addition, a measure widely used and little studied for the control of diseases and nematodes in Mato Grosso is the biological control, which consists of the action of other microorganisms on phytopathogens. Thus, the objective of the present study was to evaluate the effect of Trichoderma harzianum and T. asperellum in the development (height of plants, chlorophyll and number of pods of culture of bean, in the control of anthracnose (Colletotrichum lindemuthianum, web blight (Rhizoctonia solani and in the population of Meloidogyne spp. in the soil. The experiment was accomplished in area experimental of University Federal of Mato Grosso/Campus Sinop. The experimental design was of entirely randomized with 12 parcels of 5m² each, with 3 treatments and 4 replications. The cultivar used was Whitey, carioca group, and the seed treatment performed with product Pyraclostrobin + Thiophanate Methyl + Fipronil and after drying of the inoculation of biocontrol agents and manual seeding. It was observed that the application of T. harzianum and T. asperellum, not promoted increase of chlorophyll, height of plants in bean culture, without reducing the population of Meloidogyne spp.. However, biocontrol agents have reduced the severity of anthracnose and web blight and promoted an increase in the average number of plant pods-1. It is therefore concluded that biocontrol agents show potential for application in bean culture in the North of Mato Grosso.

  9. Mechanisms Involved in Nematode Control by Endophytic Fungi.

    Science.gov (United States)

    Schouten, Alexander

    2016-08-04

    Colonization of plants by particular endophytic fungi can provide plants with improved defenses toward nematodes. Evidently, such endophytes can be important in developing more sustainable agricultural practices. The mechanisms playing a role in this quantitative antagonism are poorly understood but most likely multifactorial. This knowledge gap obstructs the progress regarding the development of endophytes or endophyte-derived constituents into biocontrol agents. In part, this may be caused by the fact that endophytic fungi form a rather heterogeneous group. By combining the knowledge of the currently characterized antagonistic endophytic fungi and their effects on nematode behavior and biology with the knowledge of microbial competition and induced plant defenses, the various mechanisms by which this nematode antagonism operates or may operate are discussed. Now that new technologies are becoming available and more accessible, the currently unresolved mechanisms can be studied in greater detail than ever before.

  10. Induction of mutations for nematode resistance in tomato

    International Nuclear Information System (INIS)

    Alameddine, A.

    1976-01-01

    The objective of this work is to develop resistance to root-knot nematodes in tomato by induction, selection and utilization of the newly created resistant strains. Seeds of two varieties of tomato Lycopersicon esculentum L., namely Amcopack and Supermarmande, were subjected to various doses of gamma rays ranging from 10 Krads to 40 Krads in an effort to gain resistance to Meloidogyne incognita Chitwood, the prevalent species of nematodes in Lebanon. The variety Supermarmande seemed not to be affected by irradiation while Amcopack gained some resistance with a corresponding increase in the dose of radiation. The data suggest that in a variety like Amcopack, irradiation may stimulate resistance while in others like Supermarmande, susceptibility is not reduced with a corresponding increase of dosage. Those alterations in reaction within varieties may be due to genetic differences which allow some varieties to acquire resistance to nematodes when exposed to certain dosages, while others to suffer seriously due to sensitivity. (author)

  11. Small-molecule pheromones and hormones controlling nematode development.

    Science.gov (United States)

    Butcher, Rebecca A

    2017-05-17

    The existence of small-molecule signals that influence development in Caenorhabditis elegans has been known for several decades, but only in recent years have the chemical structures of several of these signals been established. The identification of these signals has enabled connections to be made between these small molecules and fundamental signaling pathways in C. elegans that influence not only development but also metabolism, fertility, and lifespan. Spurred by these important discoveries and aided by recent advances in comparative metabolomics and NMR spectroscopy, the field of nematode chemistry has the potential to expand dramatically in the coming years. This Perspective will focus on small-molecule pheromones and hormones that influence developmental events in the nematode life cycle (ascarosides, dafachronic acids, and nemamides), will cover more recent work regarding the biosynthesis of these signals, and will explore how the discovery of these signals is transforming our understanding of nematode development and physiology.

  12. Mechanisms of bacterial DNA replication restart

    Science.gov (United States)

    Windgassen, Tricia A; Wessel, Sarah R; Bhattacharyya, Basudeb

    2018-01-01

    Abstract Multi-protein DNA replication complexes called replisomes perform the essential process of copying cellular genetic information prior to cell division. Under ideal conditions, replisomes dissociate only after the entire genome has been duplicated. However, DNA replication rarely occurs without interruptions that can dislodge replisomes from DNA. Such events produce incompletely replicated chromosomes that, if left unrepaired, prevent the segregation of full genomes to daughter cells. To mitigate this threat, cells have evolved ‘DNA replication restart’ pathways that have been best defined in bacteria. Replication restart requires recognition and remodeling of abandoned replication forks by DNA replication restart proteins followed by reloading of the replicative DNA helicase, which subsequently directs assembly of the remaining replisome subunits. This review summarizes our current understanding of the mechanisms underlying replication restart and the proteins that drive the process in Escherichia coli (PriA, PriB, PriC and DnaT). PMID:29202195

  13. [Screening endophytic bacteria against plant-parasitic nematodes].

    Science.gov (United States)

    Peng, Shuang; Yan, Shuzhen; Chen, Shuanglin

    2011-03-01

    Plant-parasite nematode is one of the most important pathogens in plant. Our objective is to screen endophytic bacteria against plant-parasitic nematodes from plant. Endophytic bacteria were isolated and screened by testing their metabolite against Bursaphelenchus xylophilus in vitro. Those strains inhibiting B. xylophilus were selected to culture in liquid medium and fermentation conditions were optimized by orthogonal test. The stability of the antinematode substances was evaluated by various. In addition, four strains were identified by 16SrDNA sequence analysis. In total 13 strains of endophytic bacteria secreting antinematode metabolite were isolated from 6 species of plant. The supernatant of the fermentation broth of these endophytic bacteria gave 100% mortality of nematodes after treated as the follows: 1 ml each was mixed with 0.2 ml of the suspension of nematodes (2000 nematodes/ml) then incubated at 250C for 24 h, some of which could led to leakage or dissolution of nematodes. Among them, four strains, BCM2, SZ5, CCM7 and DP1, showed stronger activity than others. The supernatants diluted three times also gave not less than 95% mortality after 24 h treatment, and those from DP1 and SZ5 even gave 100% mortality. The fermentation conditions of the four strains were optimized and the antinematode activity grew up four times after optimization. The antinematode substances of these strains were found stable when treated with protease or heating or stored at 4 degrees C after 100 days, while instable when treated with acid or alkali. DP1 and CCM7 were identified to be Bacillus subtilis, while SZ5 and BCM2 to be Bacillus cereus. Endophytic bacteria secreting antinematode metabolite were found in economic crops. The metabolite of some strains showed strong and stable antinematode activity. Our results indicate the real potential of biocontrol by endophytic bacteria.

  14. Viability and Virulence of Entomopathogenic Nematodes Exposed to Ultraviolet Radiation.

    Science.gov (United States)

    Shapiro-Ilan, David I; Hazir, Selcuk; Lete, Luis

    2015-09-01

    Entomopathogenic nematodes (EPNs) can be highly effective biocontrol agents, but their efficacy can be reduced due to exposure to environmental stress such as from ultraviolet (UV) radiation. Our objectives were to 1) compare UV tolerance among a broad array of EPN species, and 2) investigate the relationship between reduced nematode viability (after exposure to UV) and virulence. Nematodes exposed to a UV radiation (254 nm) for 10 or 20 min were assessed separately for viability (survival) and virulence to Galleria mellonella. We compared 9 different EPN species and 15 strains: Heterorhabditis bacteriophora (Baine, fl11, Oswego, and Vs strains), H. floridensis (332), H. georgiana (Kesha), H. indica (HOM1), H. megidis (UK211), Steinernema carpocapsae (All, Cxrd, DD136, and Sal strains), S. feltiae (SN), S. rarum (17C&E), and S. riobrave (355). In viability assessments, steinernematids, particularly strains of S. carpocapsae, generally exhibited superior UV tolerance compared with the heterorhabditids. However, some heterorhabditids tended to be more tolerant than others, e.g., H. megidis and H. bacteriophora (Baine) were most susceptible and H. bacteriophora (Vs) was the only heterorhabditid that did not exhibit a significant effect after 10 min of exposure. All heterorhabditids experienced reduced viability after 20 min exposure though several S. carpocapsae strains did not. In total, after 10 or 20 min exposure, the viability of seven nematode strains did not differ from their non-UV exposed controls. In virulence assays, steinernematids (particularly S. carpocapsae strains) also tended to exhibit higher UV tolerance. However, in contrast to the viability measurements, all nematodes experienced a reduction in virulence relative to their controls. Correlation analysis revealed that viability among nematode strains is not necessarily related to virulence. In conclusion, our results indicate that the impact of UV varies substantially among EPNs, and viability alone

  15. Microbeam irradiation of the C. elegans nematode

    International Nuclear Information System (INIS)

    Bertucci, Antonella; Brenner, David J.; Pocock, Roger D.J.; Randers-Pehrson, Gerhard

    2009-01-01

    The understanding of complex radiation responses in biological systems, such as non-targeted effects as represented by the bystander response, can be enhanced by the use of genetically amenable model organisms. Almost all bystander studies to date have been carried out by using conventional single-cell in vitro systems, which are useful tools to characterize basic cellular and molecular responses. A few studies have been reported in monolayer explants and bystander responses have been also investigated in a three-dimensional normal human tissue system. However, despite the well-know usefulness of in vitro models, they cannot capture the complexity of radiation responses of living systems such as animal models. To carry out in vivo studies on the bystander effect we have developed a new technique to expose living organisms using proton microbeams. We report the use of a nematode C. elegans strain with a Green Fluorescent Protein (GFP) reporter for the hsp-4 heat-shock gene as an in vivo model for radiation studies. Exposing animals to heat and chemicals stressors leads to whole body increases in the hsp-4 protein reflected by enhanced fluorescence. We report here that γ-rays also can induce stress response in a dose dependent manner. However, whole body exposure to stress agents does not allow for evaluation of distance dependent response in non targeted tissues: the so-called bystander effect. We used the RARAF microbeam to site specifically deliver 3 MeV protons to a site in the tail of young worms. GFP expression was enhanced after 24 hours in a number dependent manner at distances > 100 μm from the site of irradiation. (author)

  16. Weight gain and resistance to gastrointestinal nematode infections in two genetically diverse groups of cattle.

    Science.gov (United States)

    Höglund, Johan; Hessle, Anna; Zaralis, Konstantinos; Arvidsson-Segerkvist, Katarina; Athanasiadou, Spiridoula

    2018-01-15

    Body weight gain (BWG) and gastrointestinal nematode challenge (GIN) were investigated in two genetically diverse groups of cattle. Thirty-two dairy calves (D=Swedish Red/Holstein) and 31 dairy×beef crosses (C=Swedish Red/Holstein×Charolais) pairwise matched by dam breed and birth dates, were monitored for ≈20 weeks on a pasture grazed by cattle in the previous year. At turn-out, animals (between 6 and 12 months age) from each genotype were either infected with 5000 third stage (L3) Ostertagia ostertagi (50%) and Cooperia oncophora (50%) larvae (H, high-exposure); or treated monthly with 0.5mg ivermectin (Noromectin ® , Pour-on) per kg bodyweight to remove worms ingested (L, low-exposure). Animals were weighed every fortnight and individual BWG was calculated. Faecal and blood samples were collected every four weeks throughout the experiment for nematode faecal egg counts (FEC) and larvae cultures and serum pepsinogen concentrations (SPC), respectively. Nematode eggs were observed 29 days post turn-out in both H groups. FEC peaked to around 200 eggs per gram (epg) on days 58 and 85 respectively in both H groups. FEC were also observed in the L groups at the same time, but mean epg remained very low (3.5 IU tyrosine whereas only six DH animals reached similar pepsinogen levels. The level of infection (H and L) significantly affected BWG in both genotypes. Even though there was no statistically significant genotype (C or D)×treatment (H or L) interaction, there was a larger difference in body weight of H and L in C (37kg) compared to D (17kg) genotypes at the end of the experiment. Our data collectively support the view crossbred (C) animals experience the impact of gastrointestinal parasitism more severely compared to pure dairy (D) first season grazers. The mechanisms that underpin this remains speculative. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Life History Responses and Gene Expression Profiles of the Nematode Pristionchus pacificus Cultured on Cryptococcus Yeasts.

    Directory of Open Access Journals (Sweden)

    Gaurav V Sanghvi

    Full Text Available Nematodes, the earth's most abundant metazoa are found in all ecosystems. In order to survive in diverse environments, they have evolved distinct feeding strategies and they can use different food sources. While some nematodes are specialists, including parasites of plants and animals, others such as Pristionchus pacificus are omnivorous feeders, which can live on a diet of bacteria, protozoans, fungi or yeast. In the wild, P. pacificus is often found in a necromenic association with beetles and is known to be able to feed on a variety of microbes as well as on nematode prey. However, in laboratory studies Escherichia coli OP50 has been used as standard food source, similar to investigations in Caenorhabditis elegans and it is unclear to what extent this biases the obtained results and how relevant findings are in real nature. To gain first insight into the variation in traits induced by a non-bacterial food source, we study Pristionchus-fungi interactions under laboratory conditions. After screening different yeast strains, we were able to maintain P. pacificus for at least 50-60 generations on Cryptococcus albidus and Cryptococcus curvatus. We describe life history traits of P. pacificus on both yeast strains, including developmental timing, survival and brood size. Despite a slight developmental delay and problems to digest yeast cells, which are both reflected at a transcriptomic level, all analyses support the potential of Cryptococcus strains as food source for P. pacificus. In summary, our work establishes two Cryptococcus strains as alternative food source for P. pacificus and shows change in various developmental, physiological and morphological traits, including the transcriptomic profiles.

  18. Comparative transcriptomics of the nematode gut identifies global shifts in feeding mode and pathogen susceptibility.

    Science.gov (United States)

    Lightfoot, James W; Chauhan, Veeren M; Aylott, Jonathan W; Rödelsperger, Christian

    2016-03-05

    The nematode Pristionchus pacificus has been established as a model for comparative studies using the well known Caenorhabditis elegans as a reference. Despite their relatedness, previous studies have revealed highly divergent development and a number of morphological differences including the lack of a pharyngal structure, the grinder, used to physically lyse the ingested bacteria in C. elegans. To complement current knowledge about developmental and ecological differences with a better understanding of their feeding modes, we have sequenced the intestinal transcriptomes of both nematodes. In total, we found 464 intestine-enriched genes in P. pacificus and 724 in C. elegans, of which the majority (66%) has been identified by previous studies. Interestingly, only 15 genes could be identified with shared intestinal enrichment in both species, of which three genes are Hedgehog signaling molecules supporting a highly conserved role of this pathway for intestinal development across all metazoa. At the level of gene families, we find similar divergent trends with only five families displaying significant intestinal enrichment in both species. We compared our data with transcriptomic responses to various pathogens. Strikingly, C. elegans intestine-enriched genes showed highly significant overlaps with pathogen response genes whereas this was not the case for P. pacificus, indicating shifts in pathogen susceptibility that might be explained by altered feeding modes. Our study reveals first insights into the evolution of feeding systems and the associated changes in intestinal gene expression that might have facilitated nematodes of the P. pacificus lineage to colonize new environments. These findings deepen our understanding about how morphological and genomic diversity is created during the course of evolution.

  19. Statistical and Economic Techniques for Site-specific Nematode Management.

    Science.gov (United States)

    Liu, Zheng; Griffin, Terry; Kirkpatrick, Terrence L

    2014-03-01

    Recent advances in precision agriculture technologies and spatial statistics allow realistic, site-specific estimation of nematode damage to field crops and provide a platform for the site-specific delivery of nematicides within individual fields. This paper reviews the spatial statistical techniques that model correlations among neighboring observations and develop a spatial economic analysis to determine the potential of site-specific nematicide application. The spatial econometric methodology applied in the context of site-specific crop yield response contributes to closing the gap between data analysis and realistic site-specific nematicide recommendations and helps to provide a practical method of site-specifically controlling nematodes.

  20. Modelling nematode movement using time-fractional dynamics.

    Science.gov (United States)

    Hapca, Simona; Crawford, John W; MacMillan, Keith; Wilson, Mike J; Young, Iain M

    2007-09-07

    We use a correlated random walk model in two dimensions to simulate the movement of the slug parasitic nematode Phasmarhabditis hermaphrodita in homogeneous environments. The model incorporates the observed statistical distributions of turning angle and speed derived from time-lapse studies of individual nematode trails. We identify strong temporal correlations between the turning angles and speed that preclude the case of a simple random walk in which successive steps are independent. These correlated random walks are appropriately modelled using an anomalous diffusion model, more precisely using a fractional sub-diffusion model for which the associated stochastic process is characterised by strong memory effects in the probability density function.

  1. The yeast replicative aging model.

    Science.gov (United States)

    He, Chong; Zhou, Chuankai; Kennedy, Brian K

    2018-03-08

    It has been nearly three decades since the budding yeast Saccharomyces cerevisiae became a significant model organism for aging research and it has emerged as both simple and powerful. The replicative aging assay, which interrogates the number of times a "mother" cell can divide and produce "daughters", has been a stalwart in these studies, and genetic approaches have led to the identification of hundreds of genes impacting lifespan. More recently, cell biological and biochemical approaches have been developed to determine how cellular processes become altered with age. Together, the tools are in place to develop a holistic view of aging in this single-celled organism. Here, we summarize the current state of understanding of yeast replicative aging with a focus on the recent studies that shed new light on how aging pathways interact to modulate lifespan in yeast. Copyright © 2018. Published by Elsevier B.V.

  2. Replication confers β cell immaturity.

    Science.gov (United States)

    Puri, Sapna; Roy, Nilotpal; Russ, Holger A; Leonhardt, Laura; French, Esra K; Roy, Ritu; Bengtsson, Henrik; Scott, Donald K; Stewart, Andrew F; Hebrok, Matthias

    2018-02-02

    Pancreatic β cells are highly specialized to regulate systemic glucose levels by secreting insulin. In adults, increase in β-cell mass is limited due to brakes on cell replication. In contrast, proliferation is robust in neonatal β cells that are functionally immature as defined by a lower set point for glucose-stimulated insulin secretion. Here we show that β-cell proliferation and immaturity are linked by tuning expression of physiologically relevant, non-oncogenic levels of c-Myc. Adult β cells induced to replicate adopt gene expression and metabolic profiles resembling those of immature neonatal β that proliferate readily. We directly demonstrate that priming insulin-producing cells to enter the cell cycle promotes a functionally immature phenotype. We suggest that there exists a balance between mature functionality and the ability to expand, as the phenotypic state of the β cell reverts to a less functional one in response to proliferative cues.

  3. Chromatin replication and histone dynamics

    DEFF Research Database (Denmark)

    Alabert, Constance; Jasencakova, Zuzana; Groth, Anja

    2017-01-01

    Inheritance of the DNA sequence and its proper organization into chromatin is fundamental for genome stability and function. Therefore, how specific chromatin structures are restored on newly synthesized DNA and transmitted through cell division remains a central question to understand cell fate...... choices and self-renewal. Propagation of genetic information and chromatin-based information in cycling cells entails genome-wide disruption and restoration of chromatin, coupled with faithful replication of DNA. In this chapter, we describe how cells duplicate the genome while maintaining its proper...... organization into chromatin. We reveal how specialized replication-coupled mechanisms rapidly assemble newly synthesized DNA into nucleosomes, while the complete restoration of chromatin organization including histone marks is a continuous process taking place throughout the cell cycle. Because failure...

  4. [Effect of the soil contamination with a potato cyst-forming nematode on the community structure of soil-inhabiting nematodes].

    Science.gov (United States)

    Gruzdeva, L I; Suzhchuk, A A

    2008-01-01

    Nematode community structure of the potato fields with different infection levels of potato cyst-forming nematode (PCN) such as 10, 30 and 214 cysts per 100 g of soil has been investigated. The influence of specialized parasite on nematode fauna and dominance character of different ecological-trophic groups were described. Parasitic nematode genera in natural meadow biocenosis and agrocenoses without PCN are Paratylenchus, Tylenchorhynchus, and Helicotylenchus. It is established, that Paratylenchus nanus was the prevalent species among plant parasites at low infection level. Larvae of Globodera prevailed in the soil with middle and high infection levels and substituted individuals of other genera of parasitic nematodes. The fact of increase in number of hyphal-feeding nematode Aphelenchus avenae was revealed.

  5. Live Replication of Paravirtual Machines

    OpenAIRE

    Stodden, Daniel

    2009-01-01

    Virtual machines offer a fair degree of system state encapsulation, which promotes practical advances in fault tolerance, system debugging, profiling and security applications. This work investigates deterministic replay and semi-active replication for system paravirtualization, a software discipline trading guest kernel binar compatibility for reduced dependency on costly trap-and-emulate techniques. A primary contribution is evidence that trace capturing under a piecewise deterministic exec...

  6. In vitro replication of poliovirus

    International Nuclear Information System (INIS)

    Lubinski, J.M.

    1986-01-01

    Poliovirus is a member of the Picornaviridae whose genome is a single stranded RNA molecule of positive polarity surrounded by a proteinaceous capsid. Replication of poliovirus occurs via negative strand intermediates in infected cells using a virally encoded RNA-dependent RNA polymerase and host cell proteins. The authors have exploited the fact that complete cDNA copies of the viral genome when transfected onto susceptible cells generate virus. Utilizing the bacteriophage SP6 DNA dependent RNA polymerase system to synthesize negative strands in vitro and using these in an in vitro reaction the authors have generated full length infectious plus strands. Mutagenesis of the 5' and 3' ends of the negative and positive strands demonstrated that replication could occur either de novo or be extensions of the templates from their 3' ends or from nicks occurring during replication. The appearance of dimeric RNA molecules generated in these reactions was not dependent upon the same protein required for de novo initiation. Full length dimeric RNA molecules using a 5' 32 P end-labelled oligo uridylic acid primer and positive strand template were demonstrated in vitro containing only the 35,000 Mr host protein and the viral RNA-dependent RNA polymerase. A model for generating positive strands without protein priming by cleavage of dimeric RNA molecules was proposed

  7. Low endemism, continued deep-shallow interchanges, and evidence for cosmopolitan distributions in free-living marine nematodes (order Enoplida

    Directory of Open Access Journals (Sweden)

    Thomas W Kelley

    2010-12-01

    Full Text Available Abstract Background Nematodes represent the most abundant benthic metazoa in one of the largest habitats on earth, the deep sea. Characterizing major patterns of biodiversity within this dominant group is a critical step towards understanding evolutionary patterns across this vast ecosystem. The present study has aimed to place deep-sea nematode species into a phylogenetic framework, investigate relationships between shallow water and deep-sea taxa, and elucidate phylogeographic patterns amongst the deep-sea fauna. Results Molecular data (18 S and 28 S rRNA confirms a high diversity amongst deep-sea Enoplids. There is no evidence for endemic deep-sea lineages in Maximum Likelihood or Bayesian phylogenies, and Enoplids do not cluster according to depth or geographic location. Tree topologies suggest frequent interchanges between deep-sea and shallow water habitats, as well as a mixture of early radiations and more recently derived lineages amongst deep-sea taxa. This study also provides convincing evidence of cosmopolitan marine species, recovering a subset of Oncholaimid nematodes with identical gene sequences (18 S, 28 S and cox1 at trans-Atlantic sample sites. Conclusions The complex clade structures recovered within the Enoplida support a high global species richness for marine nematodes, with phylogeographic patterns suggesting the existence of closely related, globally distributed species complexes in the deep sea. True cosmopolitan species may additionally exist within this group, potentially driven by specific life history traits of Enoplids. Although this investigation aimed to intensively sample nematodes from the order Enoplida, specimens were only identified down to genus (at best and our sampling regime focused on an infinitesimal small fraction of the deep-sea floor. Future nematode studies should incorporate an extended sample set covering a wide depth range (shelf, bathyal, and abyssal sites, utilize additional genetic loci (e

  8. [Diversity of actinomycetes associated with root-knot nematode and their potential for nematode control].

    Science.gov (United States)

    Luo, Hong-li; Sun, Man-hong; Xie, Jian-ping; Liu, Zhi-heng; Huang, Ying

    2006-08-01

    Twenty actinomycetes were isolated from root-knot nematode eggs and females collected from 11 plant root samples infested by Meloidogyne spp.. The isolates were assigned to the genera Streptomyces, Nocardia and Pseudonocardia respectively, based on analysis of morphological characteristics, cell-wall DAPs and 16S rRNA gene sequences. 80% of them were streptomycetes. Biocontrol potential of the isolates against Meloidogyne hapla was evaluated in liquid culture in vitro. The average percentages of egg parasitism, egg hatching, and juvenile mortality were 54.1, 40.4 and 26.2, respectively. Three Streptomyces strains and one Nocardia strain with high pathogenicity in vitro were selected to determine their ability to reduce tomato root galls in greenhouse. The results demonstrated good biocontrol efficacy (31.4%-56.4%) of the strains.

  9. Differential Selection by Nematodes on an Introduced Biocontrol Fungus vs. Indigenous Fungi in Nonsterile Soil.

    Science.gov (United States)

    Kim, Tae Gwan; Knudsen, Guy R

    2018-03-15

    Trophic interactions of introduced biocontrol fungi with soil animals can bea key determinant in the fungal proliferation and activity.This study investigated trophic interaction of an introduced biocontrol fungus with soil nematodes. The biocontrol fungus Trichoderma harzianum ThzID1-M3 and the fungivorous nematode Aphelenchoides sp. (10 per gram of soil) were added to nonsterile soil, and microbial populations were monitored for 40 days. Similar results were obtained when the experiment was duplicated. ThzID1-M3 stimulated the population growth of indigenous nematodes ( p nematodes did not increase in number and the added Aphelenchoides sp. nematodes almost disappeared by day 10. With ThzID1-M3, population growth of nematodes was rapid between 5 and 10 days after treatment. ThzID1-M3 biomass peaked on day 5, dropped at day 10, and then almost disappeared at day 20, which was not influenced by the addition of nematodes.In contrast, a large quantity of ThzID1-M3 hyphae were present in a heat-treated soil in which nematodes were eliminated.Total fungal biomass in all treatments peaked on day 5 and subsequently decreased.Addition of nematodes increased the total fungal biomass ( p nematode population growth; however, hyphae of the introduced fungus when densely localized did.The results suggest that soil fungivorous nematodes are an important constraint onhyphal proliferation of fungal agents introduced into natural soils.

  10. Stem nematode counteracts plant resistance of aphids in alfalfa, Medicago sativa.

    Science.gov (United States)

    Ramirez, Ricardo A; Spears, Lori R

    2014-10-01

    Plants are exploited by a diverse community of insect herbivores and phytopathogens that interact indirectly through plant-mediated interactions. Generally, plants are thought to respond to insects and pathogens through different defensive signaling pathways. As plants are selected for resistance to one phytophagous organism type (insect vs. pathogen) in managed systems, it is not clear how this selection may affect community interactions. This study examined the effect of nematode-resistant varieties on aphid (Acyrthosiphon pisum) suppression, and then determined how infection by the stem nematode, Ditylenchus dipsaci, mediated ecological effects on aphids and on plant defense proteins. Four alfalfa (Medicago sativa) varieties were selected with resistance to nematodes only (+,-), aphids only (-,+), nematodes and aphids (+,+), and susceptibility to nematodes and aphids (-,-). Field and greenhouse experiments were conducted to isolate the effect of nematode infection and aphid abundance on each variety. We found that varieties resistant to nematode, regardless of aphid resistance, had the lowest aphid counts, suggesting possible cross-resistance. Aphid abundance, however, increased when plants were exposed to nematodes. Resistant varieties were associated with elevated saponins but these compounds were not affected by insect or pathogen feeding. Concentrations of peroxidases and trypsin inhibitors, however, were increased in nematode resistant varieties when exposed to nematodes and aphids, respectively. The patterns of plant defense were variable, and a combination of resistance traits and changes in nutrient availability may drive positive interactions between nematodes and aphids aboveground.

  11. The Ditylenchus destructor genome provides new insights into the evolution of plant parasitic nematodes.

    Science.gov (United States)

    Zheng, Jinshui; Peng, Donghai; Chen, Ling; Liu, Hualin; Chen, Feng; Xu, Mengci; Ju, Shouyong; Ruan, Lifang; Sun, Ming

    2016-07-27

    Plant-parasitic nematodes were found in 4 of the 12 clades of phylum Nematoda. These nematodes in different clades may have originated independently from their free-living fungivorous ancestors. However, the exact evolutionary process of these parasites is unclear. Here, we sequenced the genome sequence of a migratory plant nematode, Ditylenchus destructor We performed comparative genomics among the free-living nematode, Caenorhabditis elegans and all the plant nematodes with genome sequences available. We found that, compared with C. elegans, the core developmental control processes underwent heavy reduction, though most signal transduction pathways were conserved. We also found D. destructor contained more homologies of the key genes in the above processes than the other plant nematodes. We suggest that Ditylenchus spp. may be an intermediate evolutionary history stage from free-living nematodes that feed on fungi to obligate plant-parasitic nematodes. Based on the facts that D. destructor can feed on fungi and has a relatively short life cycle, and that it has similar features to both C. elegans and sedentary plant-parasitic nematodes from clade 12, we propose it as a new model to study the biology, biocontrol of plant nematodes and the interaction between nematodes and plants. © 2016 The Author(s).

  12. High-throughput sequencing of nematode communities from total soil DNA extractions

    DEFF Research Database (Denmark)

    Sapkota, Rumakanta; Nicolaisen, Mogens

    2015-01-01

    nematodes without the need for enrichment was developed. Using this strategy on DNA templates from a set of 22 agricultural soils, we obtained 64.4% sequences of nematode origin in total, whereas the remaining sequences were almost entirely from other metazoans. The nematode sequences were derived from...... in previous sequence-based studies are not nematode specific but also amplify other groups of organisms such as fungi and plantae, and thus require a nematode enrichment step that may introduce biases. Results: In this study an amplification strategy which selectively amplifies a fragment of the SSU from...... a broad taxonomic range and most sequences were from nematode taxa that have previously been found to be abundant in soil such as Tylenchida, Rhabditida, Dorylaimida, Triplonchida and Araeolaimida. Conclusions: Our amplification and sequencing strategy for assessing nematode diversity was able to collect...

  13. Gender Effects on Loyalty: A Replication in an Emerging Market

    NARCIS (Netherlands)

    Babah Daouda, Falylath; Ingenbleek, Paul T.M.; Trijp, van Hans C.M.

    2017-01-01

    This paper replicates the gender-effect on object of loyalty found by
    Melnyk et al. (2009), suggesting that females are more loyal towards
    individuals and males are more loyal to groups and organizations. Results
    from Benin (West Africa) support this but find that the results

  14. Replication of micro and nano surface geometries

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard; Hocken, R.J.; Tosello, Guido

    2011-01-01

    The paper describes the state-of-the-art in replication of surface texture and topography at micro and nano scale. The description includes replication of surfaces in polymers, metals and glass. Three different main technological areas enabled by surface replication processes are presented......: manufacture of net-shape micro/nano surfaces, tooling (i.e. master making), and surface quality control (metrology, inspection). Replication processes and methods as well as the metrology of surfaces to determine the degree of replication are presented and classified. Examples from various application areas...... are given including replication for surface texture measurements, surface roughness standards, manufacture of micro and nano structured functional surfaces, replicated surfaces for optical applications (e.g. optical gratings), and process chains based on combinations of repeated surface replication steps....

  15. Altitudinal Barrier to the Spread of an Invasive Species: Could the Pyrenean Chain Slow the Natural Spread of the Pinewood Nematode?

    Directory of Open Access Journals (Sweden)

    Julien Haran

    Full Text Available Mountain ranges may delimit the distribution of native species as well as constitute potential barriers to the spread of invasive species. The invasive pinewood nematode, Bursaphelenchus xylophilus, is a severe forest pest inducing pine wilt disease. It is vectored in Europe by a native long-horned beetle, Monochamus galloprovincialis. This study explored the potential of the Pyrenean chain to slow or prevent the natural spread of nematode-infested beetles from the Iberian Peninsula, where the nematode is established and is expanding its range, towards France and the rest of Europe. An analysis of the genetic structure and migration patterns of the beetle populations throughout the Pyrenean mountain range was combined with a spread model simulating the potential movements of nematode-infested beetles across it. The central part of the Pyrenees, which corresponds to the highest elevation zone, was shown to prevent gene flow between the French and Spanish populations of M. galloprovincialis on each side of the mountains. Conversely, strong admixture was detected between populations located on both sides of low elevation hills, and especially at the east and west extremities of the mountain range. Simulations of the spread of nematode-infested beetles under various thresholds of beetle survival and pine wilt disease expression gave results consistent with the variation in genetic make-up, suggesting that western and eastern hillsides may represent corridors favoring natural spread of the nematode from the Iberian Peninsula to France. Simulations also showed that temperature rise due to climate change may significantly reduce the extent of the barrier formed by highest elevations. Our results support the hypothesis that the Pyrenean chain represents a partial barrier to the natural spread of nematode-infested beetles. These results, which have to be considered together with potential human-assisted long-distance spread of the nematode, highlight

  16. DNA Copy-Number Control through Inhibition of Replication Fork Progression

    Directory of Open Access Journals (Sweden)

    Jared T. Nordman

    2014-11-01

    Full Text Available Proper control of DNA replication is essential to ensure faithful transmission of genetic material and prevent chromosomal aberrations that can drive cancer progression and developmental disorders. DNA replication is regulated primarily at the level of initiation and is under strict cell-cycle regulation. Importantly, DNA replication is highly influenced by developmental cues. In Drosophila, specific regions of the genome are repressed for DNA replication during differentiation by the SNF2 domain-containing protein SUUR through an unknown mechanism. We demonstrate that SUUR is recruited to active replication forks and mediates the repression of DNA replication by directly inhibiting replication fork progression instead of functioning as a replication fork barrier. Mass spectrometry identification of SUUR-associated proteins identified the replicative helicase member CDC45 as a SUUR-associated protein, supporting a role for SUUR directly at replication forks. Our results reveal that control of eukaryotic DNA copy number can occur through the inhibition of replication fork progression.

  17. Profiling nematode communities in unmanaged flowerbed and agricultural field soils in Japan by DNA barcode sequencing.

    Directory of Open Access Journals (Sweden)

    Hisashi Morise

    Full Text Available Soil nematodes play crucial roles in the soil food web and are a suitable indicator for assessing soil environments and ecosystems. Previous nematode community analyses based on nematode morphology classification have been shown to be useful for assessing various soil environments. Here we have conducted DNA barcode analysis for soil nematode community analyses in Japanese soils. We isolated nematodes from two different environmental soils of an unmanaged flowerbed and an agricultural field using the improved flotation-sieving method. Small subunit (SSU rDNA fragments were directly amplified from each of 68 (flowerbed samples and 48 (field samples isolated nematodes to determine the nucleotide sequence. Sixteen and thirteen operational taxonomic units (OTUs were obtained by multiple sequence alignment from the flowerbed and agricultural field nematodes, respectively. All 29 SSU rDNA-derived OTUs (rOTUs were further mapped onto a phylogenetic tree with 107 known nematode species. Interestingly, the two nematode communities examined were clearly distinct from each other in terms of trophic groups: Animal predators and plant feeders were markedly abundant in the flowerbed soils, in contrast, bacterial feeders were dominantly observed in the agricultural field soils. The data from the flowerbed nematodes suggests a possible food web among two different trophic nematode groups and plants (weeds in the closed soil environment. Finally, DNA sequences derived from the mitochondrial cytochrome oxidase c subunit 1 (COI gene were determined as a DNA barcode from 43 agricultural field soil nematodes. These nematodes were assigned to 13 rDNA-derived OTUs, but in the COI gene analysis were assigned to 23 COI gene-derived OTUs (cOTUs, indicating that COI gene-based barcoding may provide higher taxonomic resolution than conventional SSU rDNA-barcoding in soil nematode community analysis.

  18. Profiling Nematode Communities in Unmanaged Flowerbed and Agricultural Field Soils in Japan by DNA Barcode Sequencing

    Science.gov (United States)

    Morise, Hisashi; Miyazaki, Erika; Yoshimitsu, Shoko; Eki, Toshihiko

    2012-01-01

    Soil nematodes play crucial roles in the soil food web and are a suitable indicator for assessing soil environments and ecosystems. Previous nematode community analyses based on nematode morphology classification have been shown to be useful for assessing various soil environments. Here we have conducted DNA barcode analysis for soil nematode community analyses in Japanese soils. We isolated nematodes from two different environmental soils of an unmanaged flowerbed and an agricultural field using the improved flotation-sieving method. Small subunit (SSU) rDNA fragments were directly amplified from each of 68 (flowerbed samples) and 48 (field samples) isolated nematodes to determine the nucleotide sequence. Sixteen and thirteen operational taxonomic units (OTUs) were obtained by multiple sequence alignment from the flowerbed and agricultural field nematodes, respectively. All 29 SSU rDNA-derived OTUs (rOTUs) were further mapped onto a phylogenetic tree with 107 known nematode species. Interestingly, the two nematode communities examined were clearly distinct from each other in terms of trophic groups: Animal predators and plant feeders were markedly abundant in the flowerbed soils, in contrast, bacterial feeders were dominantly observed in the agricultural field soils. The data from the flowerbed nematodes suggests a possible food web among two different trophic nematode groups and plants (weeds) in the closed soil environment. Finally, DNA sequences derived from the mitochondrial cytochrome oxidase c subunit 1 (COI) gene were determined as a DNA barcode from 43 agricultural field soil nematodes. These nematodes were assigned to 13 rDNA-derived OTUs, but in the COI gene analysis were assigned to 23 COI gene-derived OTUs (cOTUs), indicating that COI gene-based barcoding may provide higher taxonomic resolution than conventional SSU rDNA-barcoding in soil nematode community analysis. PMID:23284767

  19. Adenovirus sequences required for replication in vivo.

    OpenAIRE

    Wang, K; Pearson, G D

    1985-01-01

    We have studied the in vivo replication properties of plasmids carrying deletion mutations within cloned adenovirus terminal sequences. Deletion mapping located the adenovirus DNA replication origin entirely within the first 67 bp of the adenovirus inverted terminal repeat. This region could be further subdivided into two functional domains: a minimal replication origin and an adjacent auxillary region which boosted the efficiency of replication by more than 100-fold. The minimal origin occup...

  20. Parametrised Constants and Replication for Spatial Mobility

    DEFF Research Database (Denmark)

    Hüttel, Hans; Haagensen, Bjørn

    2009-01-01

    Parametrised replication and replication are common ways of expressing infinite computation in process calculi. While parametrised constants can be encoded using replication in the π-calculus, this changes in the presence of spatial mobility as found in e.g. the distributed π- calculus...... of the distributed π-calculus with parametrised constants and replication are incomparable. On the other hand, we shall see that there exists a simple encoding of recursion in mobile ambients....

  1. Systematics of gastrointestinal nematodes of domestic ruminants: advances between 1992 and 1995 and proposals for future research.

    Science.gov (United States)

    Lichtenfels, J R; Hoberg, E P; Zarlenga, D S

    1997-11-01

    individual species as components of mixed populations and requires highly trained specialists. Available identification keys for larvae are not well illustrated and need to be augmented. Adults: Recent advances in the identification of adult trichostrongyloids and their systematics are organized by taxonomic group. Genera included are Ostertagia, Haemonchus, Cooperia, Trichostrongylus and Nematodirus. Recently, the first phylogenetic analysis of the Trichostrongylidae family established monophyly for the family. A similar analysis of the Molineidae is needed. Ostertagia: Several studies of polymorphism summarized the phenomenon and listed 19 polymorphic species in five genera. Two studies of DNA differences within and among polymorphic species of Ostertagiinae supported earlier hypotheses that the species pairs represent polymorphic species. A phylogenetic analysis of the Ostertagiinae and generic concepts are needed. Haemonchus: A key to three species of Haemonchus provides, for the first time, morphological characteristics for the microscopical identification to species of individual adult nematodes of either sex. The Food and Drug Administration is now requiring that results of drug trials include identification of Haemonchus to species. Cooperia: Studies using random amplified polymorphic DNA methods showed a high degree of variation within and among C. oncophora/C. surnabada, but supported a polymorphic relationship for the species pair. A phylogenetic analysis of the Cooperiinae is needed. Trichostrongylus: Restriction Fragment Length Polymorphisms (RFLPs) of genomic DNA of two strains of T. colubriformis indicated a high degree of intra- and inter-strain DNA polymorphism. However, other studies demonstrated expected species level differences between T. colubriformis and T. vitrinus using Random Amplified Polymorphic DNA (RAPD) methods. Sequences of the second Internal Transcribed Spacer Region (ITS-2) ribosomal repeat showed sequence differences of 1.3-7.6% among five

  2. The dynamics of nematode infections of farmed ruminants

    NARCIS (Netherlands)

    Roberts, M.G.; Heesterbeek, J.A.P.

    1995-01-01

    In this paper the dynamics and control of nematode parasites of farmed ruminants are discussed via a qualitative analysis of a differential equation model. To achieve this a quantity, 'the basic reproduction quotient' (Q0), whose definition coincides with previous definitions of R0 for

  3. Foraging behavior and virulence of some entomopathogenic nematodes

    Directory of Open Access Journals (Sweden)

    Manana A. Lortkipanidze

    2016-06-01

    Full Text Available At present the biological control as a pest control technology is becoming more desirable. Biological formulations on basis of entomopathogenic nematodes are one of the effective means for the protection of agricultural and forest plants from harmful insects. Nowadays, the use of entomopathogenic nematodes as biological control agents is a key component in IPM system. The foraging strategies of entomopathogenic nematodes (EPNs vary between species. This variation is consistent with use of different foraging strategies between ambush, cruise and intermediate to find their host insects. In order to ambush prey, some species of EPNs nictate, or raise their bodies of the soil surface so they are better poised to attach passing insects, other species adopt a cruising strategy and rarely nictate. Some species adopt an intermediate strategy between ambush and cruise. We compared in laboratory the foraging strategies of the entomopathogenic nematode species: Steinernema carpocapsae, Heterorhabditis bacteriophora and the recently described species Steinernema tbilisiensis and assessed their virulence against mealworm beetle, Tenebrio molitor L. (Coleoptera: Tenebrionidae. The tests showed that S. tbilisiensis adopts both foraging strategies.

  4. Pack hunting by a common soil amoeba on nematodes

    NARCIS (Netherlands)

    Geisen, Stefan; Rosengarten, J.; Koller, R.; Mulder, Christian; Urich, T.; Bonkowski, M.

    2015-01-01

    Soils host the most complex communities on Earth,
    including the most diverse and abundant eukaryotes,
    i.e. heterotrophic protists. Protists are generally con-
    sidered as bacterivores, but evidence for negative
    interactions with nematodes both from laboratory and
    field studies

  5. A critique of current methods in nematode taxonomy | Abebe ...

    African Journals Online (AJOL)

    In the past few decades, there have been efforts to integrate molecular methods and digital 3D image-capturing technology in nematode taxonomy, the former to enhance the accuracy of identification of such a taxonomically challenging group and the latter to communicate morphological data. While the employment of ...

  6. Nematode Infections Are Risk Factors for Staphylococcal Infection in Children

    Directory of Open Access Journals (Sweden)

    Sandra F Moreira-Silva

    2002-04-01

    Full Text Available Nematode infection may be a risk factor for pyogenic liver abscess in children and we hypothesized that the immunomodulation induced by those parasites would be a risk factor for any staphylococcal infection in children. The present study was designed to compare, within the same hospital, the frequency of intestinal nematodes and Toxocara infection in children with and without staphylococcal infections. From October 1997 to February 1998, 80 children with staphylococcal infection and 110 children with other diseases were submitted to fecal examination, serology for Toxocara sp., evaluation of plasma immunoglobulin levels, and eosinophil counts. Mean age, gender distribution, birthplace, and socioeconomic conditions did not differ significantly between the two groups. Frequency of intestinal nematodes and positive serology for Toxocara, were remarkably higher in children with staphylococcal infections than in the non-staphylococcal group. There was a significant correlation between intestinal nematodes or Toxocara infection and staphylococcal infection in children, reinforced by higher eosinophil counts and higher IgE levels in these children than in the control group. One possible explanation for this association would be the enhancement of bacterial infection by the immunomodulation induced by helminth infections, due to strong activation of the Th2 subset of lymphocytes by antigens from larvae and adult worms.

  7. Human Intraocular Filariasis Caused by Dirofilaria sp. Nematode, Brazil

    Science.gov (United States)

    Diniz, Daniel G.; Dantas-Torres, Filipe; Casiraghi, Maurizio; de Almeida, Izabela N.F.; de Almeida, Luciana N.F.; Nascimento dos Santos, Jeannie; Furtado, Adriano Penha; Sobrinho, Edmundo F. de Almeida; Bain, Odile

    2011-01-01

    A case of human intraocular dirofilariasis is reported from northern Brazil. The nematode was morphologically and phylogenetically related to Dirofilaria immitis but distinct from reference sequences, including those of D. immitis infesting dogs in the same area. A zoonotic Dirofilaria species infesting wild mammals in Brazil and its implications are discussed. PMID:21529396

  8. Biochemical and Molecular Characterization of Plant-Parasitic Nematodes

    Directory of Open Access Journals (Sweden)

    I.M. de O. Abrantes

    2004-08-01

    Full Text Available Nematologists need correct species identification to carry out research, teaching, extension and other activities. Therefore, nematode taxonomy must be pursued diligently at all levels. The identification of plant-parasitic nematodes is not always easy and that of some species is especially difficult. Most of the information that nematologists use when characterizing and identifying specimens is based on morphological and morphometrical characters. Although these characters are of primary importance, in the last three decades they have been supplemented by biochemical/ molecular characters. Biochemical approaches include the separation of proteins (general proteins and isozymes by one-dimensional gel electrophoresis, isoelectric focusing, two-dimensional gel electrophoresis, and sodium dodecyl sulphate-capillary gel electrophoresis. Serology has also been found effective in the identification and quantification of nematodes, monoclonal antibodies being a more useful immunological tool than polyclonal antibodies. Identification based on the direct examination of DNA is potentially a more powerful method to characterize inter- and intra-specific variability. The development of techniques such as the polymerase chain reaction, restriction fragment length polymorphism, randomly amplified polymorphic DNA, and amplified fragment length polymorphism has increased the accuracy and speed of nematode characterization/identification. Progress continues to be made and more and more nematologists are using molecular techniques for diagnostic purposes and to assess genetic variation.

  9. Evolutionary history of nematodes associated with sweat bees.

    Science.gov (United States)

    McFrederick, Quinn S; Taylor, Douglas R

    2013-03-01

    Organisms that live in close association with other organisms make up a large part of the world's diversity. One driver of this diversity is the evolution of host-species specificity, which can occur via reproductive isolation following a host-switch or, given the correct circumstances, via cospeciation. In this study, we explored the diversity and evolutionary history of Acrostichus nematodes that are associated with halictid bees in North America. First, we conducted surveys of bees in Virginia, and found six halictid species that host Acrostichus. To test the hypothesis of cospeciation, we constructed phylogenetic hypotheses of Acrostichus based on three genes. We found Acrostichus puri and Acrostichus halicti to be species complexes comprising cryptic, host-specific species. Although several nodes in the host and symbiont phylogenies were congruent and tests for cospeciation were significant, the host's biogeography, the apparent patchiness of the association across the host's phylogeny, and the amount of evolution in the nematode sequence suggested a mixture of cospeciation, host switching, and extinction events instead of strict cospeciation. Cospeciation can explain the relationships between Ac. puri and its augochlorine hosts, but colonization of Halictus hosts is more likely than cospeciation. The nematodes are vertically transmitted, but sexual transmission is also likely. Both of these transmission modes may explain host-species specificity and congruent bee and nematode phylogenies. Additionally, all halictid hosts come from eusocial or socially polymorphic lineages, suggesting that sociality may be a factor in the suitability of hosts for Acrostichus. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Genetic diversity of the potato cyst nematode in the Netherlands

    NARCIS (Netherlands)

    Folkertsma, R.T.

    1997-01-01


    The potato cyst nematodes Globodera rostochiensis (Woll.) Skarbilovich and G. pallida (Stone) originate from the Andes region in South America and have been introduced into Western Europe since 1850. Both species are

  11. Endogenous cellulases in stylet secretions of cyst nematodes

    NARCIS (Netherlands)

    Smant, G.

    1998-01-01

    This thesis describes the identification ofβ-1,4-endoglucanases (cellulases) in stylet secretions of the two cyst nematodes species, Globodera rostochiensis and Heterodera glycines . A novel method was developed to raise monoclonal antibodies that were

  12. Limiting opportunities for cheating stabilizes virulence in insect parasitic nematodes.

    Science.gov (United States)

    Shapiro-Ilan, David; Raymond, Ben

    2016-03-01

    Cooperative secretion of virulence factors by pathogens can lead to social conflict when cheating mutants exploit collective secretion, but do not contribute to it. If cheats outcompete cooperators within hosts, this can cause loss of virulence. Insect parasitic nematodes are important biocontrol tools that secrete a range of significant virulence factors. Critically, effective nematodes are hard to maintain without live passage, which can lead to virulence attenuation. Using experimental evolution, we tested whether social cheating might explain unstable virulence in the nematode Heterorhabditis floridensis by manipulating relatedness via multiplicity of infection (MOI), and the scale of competition. Passage at high MOI, which should reduce relatedness, led to loss of fitness: virulence and reproductive rate declined together and all eight independent lines suffered premature extinction. As theory predicts, relatedness treatments had more impact under stronger global competition. In contrast, low MOI passage led to more stable virulence and increased reproduction. Moreover, low MOI lineages showed a trade-off between virulence and reproduction, particularly for lines under stronger between-host competition. Overall, this study indicates that evolution of virulence theory is valuable for the culture of biocontrol agents: effective nematodes can be improved and maintained if passage methods mitigate possible social conflicts.

  13. Farmer evaluation of biocontrol methods against rootknot nematodes in tomatoes

    OpenAIRE

    McLeod, Anni; Ndungu, Beth; Karanja, Daniel; Karanja, Peter

    2002-01-01

    This report was presented at the UK Organic Research 2002 Conference. Root-knot nematodes in tomatoes cause financial loss to Kenyan smallholders. While soil fumigation appears to be losing effectiveness two bio-control agents (bcas), Pasteuria penetrans and Verticillium chlamydosporium, appear promising. Participatory budgeting is being used to compare the bcas with chemical and other biological controls on commercial and organic smallholdings.

  14. Mechanisms Involved in Nematode Control by Endophytic Fungi

    NARCIS (Netherlands)

    Schouten, Sander

    2016-01-01

    Colonization of plants by particular endophytic fungi can provide plants with improved defenses toward nematodes. Evidently, such endophytes can be important in developing more sustainable agricultural practices. The mechanisms playing a role in this quantitative antagonism are poorly understood

  15. Parasitic nematodes in the chimpanzee population on Rubondo Island, Tanzania

    Czech Academy of Sciences Publication Activity Database

    Petrželková, Klára Judita; Hasegawa, H.; Moscovice, L. R.; Kaur, T.; Issa, M. H.; Huffman, M. A.

    2006-01-01

    Roč. 27, č. 3 (2006), s. 767-777 ISSN 0164-0291 Institutional research plan: CEZ:AV0Z60930519 Keywords : chimpanzee * introduced population * nematode * new parasite record * Rubondo Island Subject RIV: EG - Zoology Impact factor: 1.331, year: 2006

  16. Rooting out Defense Mechanisms in Wheat against Plant Parasitic Nematodes

    Science.gov (United States)

    Root-lesion nematodes (Pratylenchus spp.) are soil borne pathogens of many important agricultural crops including wheat. Pratylenchus invade root cells and feed using a stylet, resulting in cell death. Common signs of Pratylenchus damage are root lesions, girdling, and lack of lateral branching. ...

  17. Top 10 plant-parasitic nematodes in molecular plant pathology

    NARCIS (Netherlands)

    Jones, J.T.; Haegeman, A.; Danchin, E.G.J.; Gaur, H.S.; Helder, J.; Jones, M.G.K.; Kikuchi, T.; Manzanilla-López, R.; Palomares-Rius, J.E.; Wesemael, W.M.L.; Perry, R.N.

    2013-01-01

    The aim of this review was to undertake a survey of researchers working with plant-parasitic nematodes in order to determine a ‘top 10’ list of these pathogens based on scientific and economic importance. Any such list will not be definitive as economic importance will vary depending on the region

  18. Nematodes inhabit soils of forest and clear-cut areas

    Science.gov (United States)

    Alex L. Shigo; George Yelenosky

    1960-01-01

    Nematodes are present in all forest soils, but their effects on forest trees are not known. The known destructive nature of these worms on other woody crops suggests that they may also be involved in causing some of the unexplainable losses in vigor and mortality of forest trees.

  19. Nematodes for the biological control of the woodwasp, Sirex noctilio

    Science.gov (United States)

    Robin A. Bedding

    2007-01-01

    The tylenchid nematode Beddingia (Deladenus) siricidicola (Bedding) is by far the most important control agent of Sirex noctilio F., a major pest of pine plantations. It sterilizes female sirex, is density dependent, can achieve nearly 100 percent parasitism and, as a result of its complicated biology can be readily manipulated for sirex control. Bedding and Iede (2005...

  20. Effect of entomopathogenic nematodes on Plectrodera scalator (Fabricius) (Coleoptera: Cerambycidae)

    Science.gov (United States)

    Declan J. Fallon; Leellen F. Solter; Leah S. Bauer; Deborah L. Miller; James R. Cate; Michael L. McManus

    2006-01-01

    Entomopathogenic nematodes were screened for efficacy against the cottonwood borer, Plectrodera scalator (Fabricius). Steinernema feltiae SN and S. carpocapsae All killed 58 and 50% of larvae, respectively, in Wlter paper bioassays but less than 10% in diet cup bioassays. S. glaseri NJ, S. riobrave TX, and H. indica MG-13 killed less than 10% of larvae in both assays....

  1. Mitochondrial genome diversity in dagger and needle nematodes (Nematoda: Longidoridae).

    Science.gov (United States)

    Palomares-Rius, J E; Cantalapiedra-Navarrete, C; Archidona-Yuste, A; Blok, V C; Castillo, P

    2017-02-02

    Dagger and needle nematodes included in the family Longidoridae (viz. Longidorus, Paralongidorus, and Xiphinema) are highly polyphagous plant-parasitic nematodes in wild and cultivated plants and some of them are plant-virus vectors (nepovirus). The mitochondrial (mt) genomes of the dagger and needle nematodes, Xiphinema rivesi, Xiphinema pachtaicum, Longidorus vineacola and Paralongidorus litoralis were sequenced in this study. The four circular mt genomes have an estimated size of 12.6, 12.5, 13.5 and 12.7 kb, respectively. Up to date, the mt genome of X. pachtaicum is the smallest genome found in Nematoda. The four mt genomes contain 12 protein-coding genes (viz. cox1-3, nad1-6, nad4L, atp6 and cob) and two ribosomal RNA genes (rrnL and rrnS), but the atp8 gene was not detected. These mt genomes showed a gene arrangement very different within the Longidoridae species sequenced, with the exception of very closely related species (X. americanum and X. rivesi). The sizes of non-coding regions in the Longidoridae nematodes were very small and were present in a few places in the mt genome. Phylogenetic analysis of all coding genes showed a closer relationship between Longidorus and Paralongidorus and different phylogenetic possibilities for the three Xiphinema species.

  2. Radiation Effects on Nematodes: Results from IML-1 Esperiments

    Science.gov (United States)

    Nelson, G. A.; Schubert, W. W.; Kazarians, G. A.; Righards, G. F.; Benton, E. V; Benton, E. R.; Henke, R.

    1993-01-01

    The nematode Caenorhabditis elegans was exposed to natural space radiation using the ESA Biorack facility aboard Spacelab on International Microgravity Laboratory 1, STS-42. For the major experimental objective dormant animals were suspended in buffer or on agar or immobilized next to CR-39 plactic nuclear track detectors to correlate fluence of HZE particles with genetic events.

  3. Anthelmintic effects of forage chicory against parasitic nematodes in cattle

    DEFF Research Database (Denmark)

    Pena-Espinoza, Miguel Angel; Williams, Andrew; Thamsborg, Stig Milan

    BACKGROUND: Chicory (Cichorium intybus) has potential as a natural anthelmintic in livestock, however evidence of efficacy against cattle nematodes is lacking. Here, we investigated anthelmintic effects of chicory in stabled calves. METHODS: Jersey male calves (2-4 months) were stratified by live...

  4. Response of Pinus ponderosa Seedlings to Stylet-Bearing Nematodes

    Science.gov (United States)

    Viglierchio, D. R.

    1979-01-01

    Of 12 stylet-bearing nematodes used for inoculations, Pratylenchus penetrans, P. brachyurus, P. vulnus, Ditylenchus destructor, Meloidogyne incognita, M. javanica, and M. hapla reproduced on Pinus ponderosa, while Xiphinema index, Aphelenchus avenae, Paratylenehus neoamblycephalus, Tylenchulus semipenetrans, and Macroposthonia xenoplax did not. P. vulnus, P. brachyurus, P. penetrans, A. avenae, D. destructor, T. semipenetrans, and P. neoamblycephalus significantly suppressed both the shoot and root wet weights of ponderosa pine seedlings obtained from stands in five different locations. X. index significantly suppressed root wet weights, M. xenoplax siguificantly suppressed shoot wet weight, and M. incognita, M. javanica, and M. hapla suppressed neither at the inoculation levels used. Injurious nematodes tended to suppress root growth more than shoot growth. Seedlings from two locations produced greater shoot growth wet weight than did seedlings from the other three locations. The more injurious nematodes tended to cause an increase in the water content of shoots. Frequency analyses of seedling population shoot-root ratios indicated that ponderosa pine seedlings could be selected for better shoot-root ratios as well as for resistance to several pathogenic nematodes. PMID:19300659

  5. 36 CFR 910.64 - Replication.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Replication. 910.64 Section 910.64 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT CORPORATION GENERAL... DEVELOPMENT AREA Glossary of Terms § 910.64 Replication. Replication means the process of using modern methods...

  6. Exploiting replicative stress to treat cancer

    DEFF Research Database (Denmark)

    Dobbelstein, Matthias; Sørensen, Claus Storgaard

    2015-01-01

    DNA replication in cancer cells is accompanied by stalling and collapse of the replication fork and signalling in response to DNA damage and/or premature mitosis; these processes are collectively known as 'replicative stress'. Progress is being made to increase our understanding of the mechanisms...

  7. Variance Swap Replication: Discrete or Continuous?

    Directory of Open Access Journals (Sweden)

    Fabien Le Floc’h

    2018-02-01

    Full Text Available The popular replication formula to price variance swaps assumes continuity of traded option strikes. In practice, however, there is only a discrete set of option strikes traded on the market. We present here different discrete replication strategies and explain why the continuous replication price is more relevant.

  8. Why do sleeping nematodes adopt a hockey-stick-like posture?

    Directory of Open Access Journals (Sweden)

    Nora Tramm

    Full Text Available A characteristic posture is considered one of the behavioral hallmarks of sleep, and typically includes functional features such as support for the limbs and shielding of sensory organs. The nematode C. elegans exhibits a sleep-like state during a stage termed lethargus, which precedes ecdysis at the transition between larval stages. A hockey-stick-like posture is commonly observed during lethargus. What might its function be? It was previously noted that during lethargus, C. elegans nematodes abruptly rotate about their longitudinal axis. Plausibly, these "flips" facilitate ecdysis by assisting the disassociation of the old cuticle from the new one. We found that body-posture during lethargus was established using a stereotypical motor program and that body bends during lethargus quiescence were actively maintained. Moreover, flips occurred almost exclusively when the animals exhibited a single body bend, preferentially in the anterior or mid section of the body. We describe a simple biomechanical model that imposes the observed lengths of the longitudinally directed body-wall muscles on an otherwise passive elastic rod. We show that this minimal model is sufficient for generating a rotation about the anterior-posterior body axis. Our analysis suggests that posture during lethargus quiescence may serve a developmental role in facilitating flips and that the control of body wall muscles in anterior and posterior body regions are distinct.

  9. Eosinophils are required to suppress Th2 responses in Peyer's patches during intestinal infection by nematodes.

    Science.gov (United States)

    Strandmark, J; Steinfelder, S; Berek, C; Kühl, A A; Rausch, S; Hartmann, S

    2017-05-01

    Infections with enteric nematodes result in systemic type 2 helper T (Th2) responses, expansion of immunoglobulin (Ig)G1 antibodies, and eosinophilia. Eosinophils have a supportive role in mucosal Th2 induction during airway hyperreactivity. Whether eosinophils affect the local T-cell and antibody response in the gut-associated lymphoid tissue during enteric infections is unknown. We infected eosinophil-deficient ΔdblGATA-1 mice with the Th2-inducing small intestinal nematode Heligmosomoides polygyrus and found that parasite fecundity was decreased in the absence of eosinophils. A lack of eosinophils resulted in significantly augmented expression of GATA-3 and IL-4 by CD4 + T cells during acute infection, a finding strictly limited to Peyer's patches (PP). The increase in IL-4-producing cells in ΔdblGATA-1 mice was particularly evident within the CXCR5 + PD-1 + T-follicular helper cell population and was associated with a switch of germinal centre B cells to IgG1 production and elevated serum IgG1 levels. In contrast, infected wild-type mice had a modest IgG1 response in the PP, whereas successfully maintaining a population of IgA + germinal center B cells. Our results suggest a novel role for eosinophils during intestinal infection whereby they restrict IL-4 responses by follicular T helper cells and IgG1 class switching in the PP to ensure maintenance of local IgA production.

  10. Data Service: Distributed Data Capture and Replication

    Science.gov (United States)

    Warner, P. B.; Pietrowicz, S. R.

    2007-10-01

    Data Service is a critical component of the NOAO Data Management and Science Support (DMaSS) Solutions Platform, which is based on a service-oriented architecture, and is to replace the current NOAO Data Transport System. Its responsibilities include capturing data from NOAO and partner telescopes and instruments and replicating the data across multiple (currently six) storage sites. Java 5 was chosen as the implementation language, and Java EE as the underlying enterprise framework. Application metadata persistence is performed using EJB and Hibernate on the JBoss Application Server, with PostgreSQL as the persistence back-end. Although potentially any underlying mass storage system may be used as the Data Service file persistence technology, DTS deployments and Data Service test deployments currently use the Storage Resource Broker from SDSC. This paper presents an overview and high-level design of the Data Service, including aspects of deployment, e.g., for the LSST Data Challenge at the NCSA computing facilities.

  11. Security in a Replicated Metadata Catalogue

    CERN Document Server

    Koblitz, B

    2007-01-01

    The gLite-AMGA metadata has been developed by NA4 to provide simple relational metadata access for the EGEE user community. As advanced features, which will be the focus of this presentation, AMGA provides very fine-grained security also in connection with the built-in support for replication and federation of metadata. AMGA is extensively used by the biomedical community to store medical images metadata, digital libraries, in HEP for logging and bookkeeping data and in the climate community. The biomedical community intends to deploy a distributed metadata system for medical images consisting of various sites, which range from hospitals to computing centres. Only safe sharing of the highly sensitive metadata as provided in AMGA makes such a scenario possible. Other scenarios are digital libraries, which federate copyright protected (meta-) data into a common catalogue. The biomedical and digital libraries have been deployed using a centralized structure already for some time. They now intend to decentralize ...

  12. Suggestibility and negative priming: two replication studies.

    Science.gov (United States)

    David, Daniel; Brown, Richard J

    2002-07-01

    Research suggests that inhibiting the effect of irrelevant stimuli on subsequent thought and action (cognitive inhibition) may be an important component of suggestibility. Two small correlation studies were conducted to address the relationship between different aspects of suggestibility and individual differences in cognitive inhibition, operationalized as the degree of negative priming generated by to-be-ignored stimuli in a semantic categorization task. The first study found significant positive correlations between negative priming, hypnotic suggestibility, and creative imagination; a significant negative correlation was obtained between negative priming and interrogative suggestibility, demonstrating the discriminant validity of the study results. The second study replicated the correlation between negative priming and hypnotic suggestibility, using a different suggestibility measurement procedure that assessed subjective experience and hypnotic involuntariness as well as objective responses to suggestions. These studies support the notion that the ability to engage in cognitive inhibition may be an important component of hypnotic responsivity and maybe of other forms of suggestibility.

  13. Isolation and identification of entomopathogenic nematodes from citrus orchards in South Africa and their biocontrol potential against false codling moth.

    Science.gov (United States)

    Malan, Antoinette P; Knoetze, Rinus; Moore, Sean D

    2011-10-01

    A survey was conducted to determine the diversity and frequency of endemic entomopathogenic nematodes (EPN) in citrus orchards in the Western Cape, Eastern Cape and Mpumalanga provinces of South Africa. The main aim of the survey was to obtain nematodes as biological control agents against false codling moth (FCM), Thaumatotibia leucotreta, a key pest of citrus in South Africa. From a total of 202 samples, 35 (17%) tested positive for the presence of EPN. Of these, four isolates (11%) were found to be steinernematids, while 31 (89%) were heterorhabditids. Sequencing and characterisation of the internal transcribed spacer (ITS) region was used to identify all nematode isolates to species level. Morphometrics, morphology and biology of the infective juvenile (IJ) and the first-generation male were used to support molecular identification and characterisation. The Steinernema spp. identified were Steinernema khoisanae, Steinernema yirgalemense and Steinernema citrae. This is the first report of S. yirgalemense in South Africa, while for S. citrae it is the second new steinernematid to be identified from South Africa. Heterorhabditis species identified include Heterorhabditis bacteriophora, Heterorhabditis zealandica and an unknown species of Heterorhabditis. Laboratory bioassays, using 24-well bioassay disks, have shown isolates of all six species found during the survey, to be highly virulent against the last instar of FCM larvae. S. yirgalemense, at a concentration of 50IJs/FCM larva caused 100% mortality and 74% at a concentration of 200IJs/pupa. Using a sand bioassay, S. yirgalemense gave 93% control of cocooned pupae and emerging moths at a concentration of 20IJs/cm(2). This is the first report on the potential use of EPN to control the soil-borne life stages of FCM, which includes larvae, pupae and emerging moths. It was shown that emerging moths were infected with nematodes, which may aid in control and dispersal. Copyright © 2011 Elsevier Inc. All rights

  14. The feeding tube of cyst nematodes: characterisation of protein exclusion.

    Directory of Open Access Journals (Sweden)

    Sebastian Eves-van den Akker

    Full Text Available Plant parasitic nematodes comprise several groups; the most economically damaging of these are the sedentary endoparasites. Sedentary endoparasitic nematodes are obligate biotrophs and modify host root tissue, using a suite of effector proteins, to create a feeding site that is their sole source of nutrition. They feed by withdrawing host cell assimilate from the feeding site though a structure known as the feeding tube. The function, composition and molecular characteristics of feeding tubes are poorly characterised. It is hypothesised that the feeding tube facilitates uptake of host cell assimilate by acting as a molecular sieve. Several studies, using molecular mass as the sole indicator of protein size, have given contradictory results about the exclusion limits of the cyst nematode feeding tube. In this study we propose a method to predict protein size, based on protein database coordinates in silico. We tested the validity of these predictions using travelling wave ion mobility spectrometry--mass spectrometry, where predictions and measured values were within approximately 6%. We used the predictions, coupled with mass spectrometry, analytical ultracentrifugation and protein electrophoresis, to resolve previous conflicts and define the exclusion characteristics of the cyst nematode feeding tube. Heterogeneity was tested in the liquid, solid and gas phase to provide a comprehensive evaluation of three proteins of particular interest to feeding tube size exclusion, GFP, mRFP and Dual PI. The data and procedures described here could be applied to the design of plant expressed defence compounds intended for uptake into cyst nematodes. We also highlight the need to assess protein heterogeneity when creating novel fusion proteins.

  15. The feeding tube of cyst nematodes: characterisation of protein exclusion.

    Science.gov (United States)

    Eves-van den Akker, Sebastian; Lilley, Catherine J; Ault, James R; Ashcroft, Alison E; Jones, John T; Urwin, Peter E

    2014-01-01

    Plant parasitic nematodes comprise several groups; the most economically damaging of these are the sedentary endoparasites. Sedentary endoparasitic nematodes are obligate biotrophs and modify host root tissue, using a suite of effector proteins, to create a feeding site that is their sole source of nutrition. They feed by withdrawing host cell assimilate from the feeding site though a structure known as the feeding tube. The function, composition and molecular characteristics of feeding tubes are poorly characterised. It is hypothesised that the feeding tube facilitates uptake of host cell assimilate by acting as a molecular sieve. Several studies, using molecular mass as the sole indicator of protein size, have given contradictory results about the exclusion limits of the cyst nematode feeding tube. In this study we propose a method to predict protein size, based on protein database coordinates in silico. We tested the validity of these predictions using travelling wave ion mobility spectrometry--mass spectrometry, where predictions and measured values were within approximately 6%. We used the predictions, coupled with mass spectrometry, analytical ultracentrifugation and protein electrophoresis, to resolve previous conflicts and define the exclusion characteristics of the cyst nematode feeding tube. Heterogeneity was tested in the liquid, solid and gas phase to provide a comprehensive evaluation of three proteins of particular interest to feeding tube size exclusion, GFP, mRFP and Dual PI. The data and procedures described here could be applied to the design of plant expressed defence compounds intended for uptake into cyst nematodes. We also highlight the need to assess protein heterogeneity when creating novel fusion proteins.

  16. Characterizing Ancylostoma caninum transcriptome and exploring nematode parasitic adaptation

    Directory of Open Access Journals (Sweden)

    Hawdon John

    2010-05-01

    Full Text Available Abstract Background Hookworm infection is one of the most important neglected diseases in developing countries, with approximately 1 billion people infected worldwide. To better understand hookworm biology and nematode parasitism, the present study generated a near complete transcriptome of the canine hookworm Ancylostoma caninum to a very high coverage using high throughput technology, and compared it to those of the free-living nematode Caenorhabditis elegans and the parasite Brugia malayi. Results The generated transcripts from four developmental stages, infective L3, serum stimulated L3, adult male and adult female, covered 93% of the A. caninum transcriptome. The broad diversity among nematode transcriptomes was confirmed, and an impact of parasitic adaptation on transcriptome diversity was inferred. Intra-population analysis showed that A. caninum has higher coding sequence diversity than humans. Examining the developmental expression profiles of A. caninum revealed major transitions in gene expression from larval stages to adult. Adult males expressed the highest number of selectively expressed genes, but adult female expressed the highest number of selective parasitism-related genes. Genes related to parasitism adaptation and A. caninum specific genes exhibited more expression selectivity while those conserved in nematodes tend to be consistently expressed. Parasitism related genes were expressed more selectively in adult male and female worms. The comprehensive analysis of digital expression profiles along with transcriptome comparisons enabled identification of a set of parasitism genes encoding secretory proteins in animal parasitic nematode. Conclusions This study validated the usage of deep sequencing for gene expression profiling. Parasitic adaptation of the canine hookworm is related to its diversity and developmental dynamics. This comprehensive comparative genomic and expression study substantially improves our understanding of

  17. Practical application of insect-parasitic nematodes and sterile flies

    International Nuclear Information System (INIS)

    Galle, F.; Loosjes, M.

    1987-01-01

    The company 'de Groene Vlieg' started with commercial control of the onion fly by means of the sterile insect technique. At the moment 10 per cent of the Dutch spring sown onions are treated with this method. The mass-rearing, the estimations of populations and the repeated releases of sterilized flies make it a rather complicated method. It can be applied economically per field, but only in areas with a concentration of onion growing. For export we see no possibilities yet. In principle the sterile insect technique can be applied also to other flies (carrot rust fly, cabbage root fly), but a suitable artificial diet is still lacking. Since some years we also rear the insect parasitic nematodes Heterorhabditis sp. and Neoaplectana bibionis. The later is experimentally used with success against Agrotis segetum caterpillars in lettuce. Research will yield more applications of nematodes against different pests. We use Heterorhabditis sp. in practice against the black vine weevil (Otiorhynchus sulcatus), a serious pest in glass houses, tree nurseries and gardens. Good control is achieved with a dose of one half to one million nematodes per square meter in moist soil and with temperatures above 12 degrees C. The application is similar to that of a chemical insecticide. The pest is killed by symbiontic bacteria, released by the nematodes after penetrating into the body cavity of the larvae. The nematodes are delivered by mail. If cooled they can be kept alive for over four weeks in the package. We export already to Switzerland and plan to export also to Western Germany. At this moment a possible admittance is under investigation in the Netherlands for application of a nuclear polyhedrosis virus against Spodoptera exigua caterpillars

  18. Damage-associated responses of the host contribute to defence against cyst nematodes but not root-knot nematodes

    NARCIS (Netherlands)

    Shah, Syed Jehangir; Anjam, Muhammad Shahzad; Mendy, Badou; Anwer, Muhammad Arslan; Habash, Samer S.; Lozano-Torres, Jose L.; Grundler, Florian M.W.; Siddique, Shahid

    2017-01-01

    When nematodes invade and subsequently migrate within plant roots, they generate cell wall fragments (in the form of oligogalacturonides; OGs) that can act as damage-associated molecular patterns and activate host defence responses. However, the molecular mechanisms mediating damage responses in

  19. Comparison of two techniques used for the recovery of third-stage strongylid nematode larvae from herbage.

    Science.gov (United States)

    Krecek, R C; Maingi, N

    2004-07-14

    A laboratory trial to determine the efficacy of two methods in recovering known numbers of third-stage (L3) strongylid nematode larvae from herbage was carried out. Herbage samples consisting almost entirely of star grass (Cynodon aethiopicus) that had no L3 nematode parasitic larvae were collected at Onderstepoort, South Africa. Two hundred grams samples were placed in fibreglass fly gauze bags and seeded with third-stage strongylid nematode larvae at 11 different levels of herbage infectivity ranging from 50 to 8000 L3/kg. Eight replicates were prepared for each of the 11 levels of herbage infectivity. Four of these were processed using a modified automatic Speed Queen heavy-duty washing machine at a regular normal cycle, followed by isolation of larvae through centrifugation-flotation in saturated sugar solution. Larvae in the other four samples were recovered after soaking the herbage in water overnight and the larvae isolated with the Baermann technique of the washing. There was a strong correlation between the number of larvae recovered using both methods and the number of larvae in the seeded samples, indicating that the two methods give a good indication of changes in the numbers of larvae on pasture if applied in epidemiological studies. The washing machine method recovered higher numbers of larvae than the soaking and Baermann method at all levels of pasture seeding, probably because the machine washed the samples more thoroughly and a sugar centrifugation-flotation step was used. Larval suspensions obtained using the washing machine method were therefore cleaner and thus easier to examine under the microscope. In contrast, the soaking and Baermann method may be more suitable in field-work, especially in places where resources and equipment are scarce, as it is less costly in equipment and less labour intensive. Neither method recovered all the larvae from the seeded samples. The recovery rates for the washing machine method ranged from 18 to 41% while

  20. Replication dynamics of the yeast genome.

    Science.gov (United States)

    Raghuraman, M K; Winzeler, E A; Collingwood, D; Hunt, S; Wodicka, L; Conway, A; Lockhart, D J; Davis, R W; Brewer, B J; Fangman, W L

    2001-10-05

    Oligonucleotide microarrays were used to map the detailed topography of chromosome replication in the budding yeast Saccharomyces cerevisiae. The times of replication of thousands of sites across the genome were determined by hybridizing replicated and unreplicated DNAs, isolated at different times in S phase, to the microarrays. Origin activations take place continuously throughout S phase but with most firings near mid-S phase. Rates of replication fork movement vary greatly from region to region in the genome. The two ends of each of the 16 chromosomes are highly correlated in their times of replication. This microarray approach is readily applicable to other organisms, including humans.

  1. Chromosomal DNA replication of Vicia faba cells

    International Nuclear Information System (INIS)

    Ikushima, Takaji

    1976-01-01

    The chromosomal DNA replication of higher plant cells has been investigated by DNA fiber autoradiography. The nuclear DNA fibers of Vicia root meristematic cells are organized into many tandem arrays of replication units or replicons which exist as clusters with respect to replication. DNA is replicated bidirectionally from the initiation points at the average rate of 0.15 μm/min at 20 0 C, and the average interinitiation interval is about 16 μm. The manner of chromosomal DNA replication in this higher plant is similar to that found in other eukaryotic cells at a subchromosomal level. (auth.)

  2. Inferential misconceptions and replication crisis

    Directory of Open Access Journals (Sweden)

    Norbert Hirschauer

    2016-12-01

    Full Text Available Misinterpretations of the p value and the introduction of bias through arbitrary analytical choices have been discussed in the literature for decades. Nonetheless, they seem to have persisted in empirical research, and criticisms of p value misuses have increased in the recent past due to the non-replicability of many studies. Unfortunately, the critical concerns that have been raised in the literature are scattered over many disciplines, often linguistically confusing, and differing in their main reasons for criticisms. Misuses and misinterpretations of the p value are currently being discussed intensely under the label “replication crisis” in many academic disciplines and journals, ranging from specialized scientific journals to Nature and Science. In a drastic response to the crisis, the editors of the journal Basic and Applied Social Psychology even decided to ban the use of p values from future publications at the beginning of 2015, a fact that has certainly added fuel to the discussions in the relevant scientific forums. Finally, in early March, the American Statistical Association released a brief formal statement on p values that explicitly addresses misuses and misinterpretations. In this context, we systematize the most serious flaws related to the p value and discuss suggestions of how to prevent them and reduce the rate of false discoveries in the future.

  3. Mammalian RAD52 Functions in Break-Induced Replication Repair of Collapsed DNA Replication Forks

    DEFF Research Database (Denmark)

    Sotiriou, Sotirios K; Kamileri, Irene; Lugli, Natalia

    2016-01-01

    Human cancers are characterized by the presence of oncogene-induced DNA replication stress (DRS), making them dependent on repair pathways such as break-induced replication (BIR) for damaged DNA replication forks. To better understand BIR, we performed a targeted siRNA screen for genes whose...... RAD52 facilitates repair of collapsed DNA replication forks in cancer cells....

  4. Repair replication in replicating and nonreplicating DNA after irradiation with uv light

    Energy Technology Data Exchange (ETDEWEB)

    Slor, H.; Cleaver, J.E.

    1978-06-01

    Ultraviolet light induces more pyrimidine dimers and more repair replication in DNA that replicates within 2 to 3 h of irradiation than in DNA that does not replicate during this period. This difference may be due to special conformational changes in DNA and chromatin that might be associated with semiconservative DNA replication.

  5. Topography measurements for determining the decay factors in surface replication

    International Nuclear Information System (INIS)

    Song, J; Zheng, A; Vorburger, T V; Rubert, P

    2008-01-01

    The electro-forming technique is used at National Institute of Standards and Technology (NIST) for the production of standard reference material (SRM) 2461 standard casings to support nationwide ballistics measurement traceability and measurement quality control in the US. In order to ensure that the SRM casings are produced with virtually the same surface topography, it is necessary to test the decay factors of the replication process. Twenty-six replica casings are replicated from the same master casing for the decay factor tests. The NIST topography measurement system is used for measurements and correlations of surface topography. The topography decays are quantified by the cross-correlation function maximum CCF max . Based on the test, it is expected that 256 SRM casings can be replicated from the same master with CCF max values higher than 95%

  6. DNA replication stress as a hallmark of cancer.

    Science.gov (United States)

    Macheret, Morgane; Halazonetis, Thanos D

    2015-01-01

    Human cancers share properties referred to as hallmarks, among which sustained proliferation, escape from apoptosis, and genomic instability are the most pervasive. The sustained proliferation hallmark can be explained by mutations in oncogenes and tumor suppressors that regulate cell growth, whereas the escape from apoptosis hallmark can be explained by mutations in the TP53, ATM, or MDM2 genes. A model to explain the presence of the three hallmarks listed above, as well as the patterns of genomic instability observed in human cancers, proposes that the genes driving cell proliferation induce DNA replication stress, which, in turn, generates genomic instability and selects for escape from apoptosis. Here, we review the data that support this model, as well as the mechanisms by which oncogenes induce replication stress. Further, we argue that DNA replication stress should be considered as a hallmark of cancer because it likely drives cancer development and is very prevalent.

  7. The Role of Cytokinin During Infection of Arabidopsis thaliana by the Cyst Nematode Heterodera schachtii.

    Science.gov (United States)

    Shanks, Carly M; Rice, J Hollis; Zubo, Yan; Schaller, G Eric; Hewezi, Tarek; Kieber, Joseph J

    2016-01-01

    Plant-parasitic cyst nematodes induce the formation of hypermetabolic feeding sites, termed syncytia, as their sole source of nutrients. The formation of the syncytium is orchestrated by the nematode, in part, by modulation of phytohormone responses, including cytokinin. In response to infection by the nematode Heterodera schachtii, cytokinin signaling is transiently induced at the site of infection and in the developing syncytium. Arabidopsis lines with reduced cytokinin sensitivity show reduced susceptibility to nematode infection, indicating that cytokinin signaling is required for optimal nematode development. Furthermore, lines with increased cytokinin sensitivity also exhibit reduced nematode susceptibility. To ascertain why cytokinin hypersensitivity reduces nematode parasitism, we examined the transcriptomes in wild type and a cytokinin-hypersensitive type-A arr Arabidopsis mutant in response to H. schachtii infection. Genes involved in the response to biotic stress and defense response were elevated in the type-A arr mutant in the absence of nematodes and were hyperinduced following H. schachtii infection, which suggests that the Arabidopsis type-A arr mutants impede nematode development because they are primed to respond to pathogen infection. These results suggest that cytokinin signaling is required for optimal H. schachtii parasitism of Arabidopsis but that elevated cytokinin signaling triggers a heightened immune response to nematode infection.

  8. Endosymbiont-based immunity in Drosophila melanogaster against parasitic nematode infection.

    Science.gov (United States)

    Yadav, Shruti; Frazer, Joanna; Banga, Ashima; Pruitt, Katherine; Harsh, Sneh; Jaenike, John; Eleftherianos, Ioannis

    2018-01-01

    Associations between endosymbiotic bacteria and their hosts represent a complex ecosystem within organisms ranging from humans to protozoa. Drosophila species are known to naturally harbor Wolbachia and Spiroplasma endosymbionts, which play a protective role against certain microbial infections. Here, we investigated whether the presence or absence of endosymbionts affects the immune response of Drosophila melanogaster larvae to infection by Steinernema carpocapsae nematodes carrying or lacking their mutualistic Gram-negative bacteria Xenorhabdus nematophila (symbiotic or axenic nematodes, respectively). We find that the presence of Wolbachia alone or together with Spiroplasma promotes the survival of larvae in response to infection with S. carpocapsae symbiotic nematodes, but not against axenic nematodes. We also find that Wolbachia numbers are reduced in Spiroplasma-free larvae infected with axenic compared to symbiotic nematodes, and they are also reduced in Spiroplasma-containing compared to Spiroplasma-free larvae infected with axenic nematodes. We further show that S. carpocapsae axenic nematode infection induces the Toll pathway in the absence of Wolbachia, and that symbiotic nematode infection leads to increased phenoloxidase activity in D. melanogaster larvae devoid of endosymbionts. Finally, infection with either type of nematode alters the metabolic status and the fat body lipid droplet size in D. melanogaster larvae containing only Wolbachia or both endosymbionts. Our results suggest an interaction between Wolbachia endosymbionts with the immune response of D. melanogaster against infection with the entomopathogenic nematodes S. carpocapsae. Results from this study indicate a complex interplay between insect hosts, endosymbiotic microbes and pathogenic organisms.

  9. Inhibition of histone deacetylases stimulates HBV replication independent of protein X

    NARCIS (Netherlands)

    van de Klundert, Maarten A. A.; Swart, Marjolein; Zaaijer, Hans L.; Kootstra, Neeltje A.

    2015-01-01

    Aim: HBV expresses an accessory protein called X (HBx), which supports HBV replication by increasing transcription from episomal templates. Here, we investigate whether HBx augments HBV replication by interfering with the deacetylation of HBV DNA associated histones by histone deacetylases (HDACs).

  10. Replication of genetic associations as pseudoreplication due to shared genealogy.

    Science.gov (United States)

    Rosenberg, Noah A; Vanliere, Jenna M

    2009-09-01

    The genotypes of individuals in replicate genetic association studies have some level of correlation due to shared descent in the complete pedigree of all living humans. As a result of this genealogical sharing, replicate studies that search for genotype-phenotype associations using linkage disequilibrium between marker loci and disease-susceptibility loci can be considered as "pseudoreplicates" rather than true replicates. We examine the size of the pseudoreplication effect in association studies simulated from evolutionary models of the history of a population, evaluating the excess probability that both of a pair of studies detect a disease association compared to the probability expected under the assumption that the two studies are independent. Each of nine combinations of a demographic model and a penetrance model leads to a detectable pseudoreplication effect, suggesting that the degree of support that can be attributed to a replicated genetic association result is less than that which can be attributed to a replicated result in a context of true independence.

  11. Multiple-strand displacement and identification of single nucleotide polymorphisms as markers of genotypic variation of Pasteuria penetrans biotypes infecting root-knot nematodes.

    Science.gov (United States)

    Nong, Guang; Chow, Virginia; Schmidt, Liesbeth M; Dickson, Don W; Preston, James F

    2007-08-01

    Pasteuria species are endospore-forming obligate bacterial parasites of soil-inhabiting nematodes and water-inhabiting cladocerans, e.g. water fleas, and are closely related to Bacillus spp. by 16S rRNA gene sequence. As naturally occurring bacteria, biotypes of Pasteuria penetrans are attractive candidates for the biocontrol of various Meloidogyne spp. (root-knot nematodes). Failure to culture these bacteria outside their hosts has prevented isolation of genomic DNA in quantities sufficient for identification of genes associated with host recognition and virulence. We have applied multiple-strand displacement amplification (MDA) to generate DNA for comparative genomics of biotypes exhibiting different host preferences. Using the genome of Bacillus subtilis as a paradigm, MDA allowed quantitative detection and sequencing of 12 marker genes from 2000 cells. Meloidogyne spp. infected with P. penetrans P20 or B4 contained single nucleotide polymorphisms (SNPs) in the spoIIAB gene that did not change the amino acid sequence, or that substituted amino acids with similar chemical properties. Individual nematodes infected with P. penetrans P20 or B4 contained SNPs in the spoIIAB gene sequenced in MDA-generated products. Detection of SNPs in the spoIIAB gene in a nematode indicates infection by more than one genotype, supporting the need to sequence genomes of Pasteuria spp. derived from single spore isolates.

  12. Fast, automated measurement of nematode swimming (thrashing without morphometry

    Directory of Open Access Journals (Sweden)

    Sattelle David B

    2009-07-01

    Full Text Available Abstract Background The "thrashing assay", in which nematodes are placed in liquid and the frequency of lateral swimming ("thrashing" movements estimated, is a well-established method for measuring motility in the genetic model organism Caenorhabditis elegans as well as in parasitic nematodes. It is used as an index of the effects of drugs, chemicals or mutations on motility and has proved useful in identifying mutants affecting behaviour. However, the method is laborious, subject to experimenter error, and therefore does not permit high-throughput applications. Existing automation methods usually involve analysis of worm shape, but this is computationally demanding and error-prone. Here we present a novel, robust and rapid method of automatically counting the thrashing frequency of worms that avoids morphometry but nonetheless gives a direct measure of thrashing frequency. Our method uses principal components analysis to remove the background, followed by computation of a covariance matrix of the remaining image frames from which the interval between statistically-similar frames is estimated. Results We tested the performance of our covariance method in measuring thrashing rates of worms using mutations that affect motility and found that it accurately substituted for laborious, manual measurements over a wide range of thrashing rates. The algorithm used also enabled us to determine a dose-dependent inhibition of thrashing frequency by the anthelmintic drug, levamisole, illustrating the suitability of the system for assaying the effects of drugs and chemicals on motility. Furthermore, the algorithm successfully measured the actions of levamisole on a parasitic nematode, Haemonchus contortus, which undergoes complex contorted shapes whilst swimming, without alterations in the code or of any parameters, indicating that it is applicable to different nematode species, including parasitic nematodes. Our method is capable of analyzing a 30 s movie in

  13. Sequence mining and transcript profiling to explore cyst nematode parasitism

    Directory of Open Access Journals (Sweden)

    Recknor Justin

    2009-01-01

    Full Text Available Abstract Background Cyst nematodes are devastating plant parasites that become sedentary within plant roots and induce the transformation of normal plant cells into elaborate feeding cells with the help of secreted effectors, the parasitism proteins. These proteins are the translation products of parasitism genes and are secreted molecular tools that allow cyst nematodes to infect plants. Results We present here the expression patterns of all previously described parasitism genes of the soybean cyst nematode, Heterodera glycines, in all major life stages except the adult male. These insights were gained by analyzing our gene expression dataset from experiments using the Affymetrix Soybean Genome Array GeneChip, which contains probeset sequences for 6,860 genes derived from preparasitic and parasitic H. glycines life stages. Targeting the identification of additional H. glycines parasitism-associated genes, we isolated 633 genes encoding secretory proteins using algorithms to predict secretory signal peptides. Furthermore, because some of the known H. glycines parasitism proteins have strongest similarity to proteins of plants and microbes, we searched for predicted protein sequences that showed their highest similarities to plant or microbial proteins and identified 156 H. glycines genes, some of which also contained a signal peptide. Analyses of the expression profiles of these genes allowed the formulation of hypotheses about potential roles in parasitism. This is the first study combining sequence analyses of a substantial EST dataset with microarray expression data of all major life stages (except adult males for the identification and characterization of putative parasitism-associated proteins in any parasitic nematode. Conclusion We have established an expression atlas for all known H. glycines parasitism genes. Furthermore, in an effort to identify additional H. glycines genes with putative functions in parasitism, we have reduced the

  14. Overcoming natural replication barriers: differential helicase requirements.

    Science.gov (United States)

    Anand, Ranjith P; Shah, Kartik A; Niu, Hengyao; Sung, Patrick; Mirkin, Sergei M; Freudenreich, Catherine H

    2012-02-01

    DNA sequences that form secondary structures or bind protein complexes are known barriers to replication and potential inducers of genome instability. In order to determine which helicases facilitate DNA replication across these barriers, we analyzed fork progression through them in wild-type and mutant yeast cells, using 2-dimensional gel-electrophoretic analysis of the replication intermediates. We show that the Srs2 protein facilitates replication of hairpin-forming CGG/CCG repeats and prevents chromosome fragility at the repeat, whereas it does not affect replication of G-quadruplex forming sequences or a protein-bound repeat. Srs2 helicase activity is required for hairpin unwinding and fork progression. Also, the PCNA binding domain of Srs2 is required for its in vivo role of replication through hairpins. In contrast, the absence of Sgs1 or Pif1 helicases did not inhibit replication through structural barriers, though Pif1 did facilitate replication of a telomeric protein barrier. Interestingly, replication through a protein barrier but not a DNA structure barrier was modulated by nucleotide pool levels, illuminating a different mechanism by which cells can regulate fork progression through protein-mediated stall sites. Our analyses reveal fundamental differences in the replication of DNA structural versus protein barriers, with Srs2 helicase activity exclusively required for fork progression through hairpin structures.

  15. Identification, Validation and Utilization of Novel Nematode-Responsive Root-Specific Promoters in Arabidopsis for Inducing Host-Delivered RNAi Mediated Root-Knot Nematode Resistance

    Directory of Open Access Journals (Sweden)

    Atul Kakrana

    2017-12-01

    Full Text Available The root-knot nematode (RKN, Meloidogyne incognita, is an obligate, sedentary endoparasite that infects a large number of crops and severely affects productivity. The commonly used nematode control strategies have their own limitations. Of late, RNA interference (RNAi has become a popular approach for the development of nematode resistance in plants. Transgenic crops capable of expressing dsRNAs, specifically in roots for disrupting the parasitic process, offer an effective and efficient means of producing resistant crops. We identified nematode-responsive and root-specific (NRRS promoters by using microarray data from the public domain and known conserved cis-elements. A set of 51 NRRS genes was identified which was narrowed down further on the basis of presence of cis-elements combined with minimal expression in the absence of nematode infection. The comparative analysis of promoters from the enriched NRRS set, along with earlier reported nematode-responsive genes, led to the identification of specific cis-elements. The promoters of two candidate genes were used to generate transgenic plants harboring promoter GUS constructs and tested in planta against nematodes. Both promoters showed preferential expression upon nematode infection, exclusively in the root in one and galls in the other. One of these NRRS promoters was used to drive the expression of splicing factor, a nematode-specific gene, for generating host-delivered RNAi-mediated nematode-resistant plants. Transgenic lines expressing dsRNA of splicing factor under the NRRS promoter exhibited upto a 32% reduction in number of galls compared to control plants.

  16. The genome and life-stage specific transcriptomes of Globodera pallida elucidate key aspects of plant parasitism by a cyst nematode

    KAUST Repository

    Cotton, James A; Lilley, Catherine J; Jones, Laura M; Kikuchi, Taisei; Reid, Adam J; Thorpe, Peter; Tsai, Isheng J; Beasley, Helen; Blok, Vivian; Cock, Peter J A; den Akker, Sebastian Eves-van; Holroyd, Nancy; Hunt, Martin; Mantelin, Sophie; Naghra, Hardeep; Pain, Arnab; Palomares-Rius, Juan E; Zarowiecki, Magdalena; Berriman, Matthew; Jones, John T; Urwin, Peter E

    2014-01-01

    -knot nematodes are the two most important plant parasitic nematode groups and together represent a global threat to food security. Results: We present the complete genome sequence of G. pallida, together with transcriptomic data from most of the nematode life

  17. Susceptibility of irradiated Galleria mellonella F1Larvae to Entomopathogenic Nematodes

    International Nuclear Information System (INIS)

    Salem, H.M.; Rizk, S.A.; Sayed, R.M.; Hussein, M.A; Hafez, S.E

    2008-01-01

    Combined effect of substerilizing doses of gamma radiation (40 and 100 Gy) and different concentrations of entomopathogenic nematodes (20, 40, 60, and 80 IJs) on the greater wax moth, Galleria mellonella was studied. The 4th larval instar resulted from irradiated male parent pupae mated with normal female were tested for susceptibility to Heterorhabditis bacteriophora BA1 and Steinernema carpocapsae BA2. The mortality rate of the larvae increased by increrasing radiation dose and nematode concentrations. The reproduction of both nematode strains decreased significantly with increasing the treatments (radiation dose and nematode concentrations). In addition, exposure to gamma radiation and entomopathogenic nematodes significantly decreased the total haemocyte count (THC) of the larvae with increasing radiation doses (40 and 100 Gy) and both nematode strains concentrations (20 and 40 IJs) and reached the minimal count at the combiend effect. Finally, larvae were more susceptible to Steinernema carpocapsa than Heterorhabditis bacteriophora. (author)

  18. Effect of the Entomogenous Nematode Nemplectana carpocapsae on the Tachinid Parasite Compsilura concinnata (Diptera: Tachinidae)

    Science.gov (United States)

    Kaya, Harry K.

    1984-01-01

    The entomogenous nematode Neoaplectana carpocapsae and its associated bacterium, Xenorhabdus nematophilus, could not infect the pupal stage of the tachinid Compsilura concinnata through the puparium. N. carpocapsae had an adverse effect on 1-, 2- and 3-day-old C. concinnata larvae within the armyworm host in petri dish tests. All 1-day-old larvae treated with nematodes died in their hosts, whereas 61% and 69% of 2- and 3-day-old larvae treated with nematodes, respectively, died. However, the survivors developed to adults. Nine to thirty-seven percent of adult tachinids which emerged from nematode-treated soil (50 nematodes/cm²) were infected with N. carpocapsae. The nematode adversely affects C. concinnata directly by the frank infection of the tachinid and indirectly by causing the premature death of the host which results in tachinid death. PMID:19295866

  19. Assessment of nematode community structure as a bioindicator in river monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wu, H.C.; Chen, P.C. [Department of Plant Pathology, National Chung Hsing University, 250 Kuo Kuan Rd, Taichung 402, Taiwan (China); Tsay, T.T., E-mail: tttsay@nchu.edu.t [Department of Plant Pathology, National Chung Hsing University, 250 Kuo Kuan Rd, Taichung 402, Taiwan (China)

    2010-05-15

    Nematode communities from river water and sediments were assessed for the abundance, feeding types, maturity indices and nematode channel ratio (NCR). The sampling sites studied included different levels of pollution and contamination from agricultural, industrial and sewage sources. The nematode abundance found in the sediment samples was more than that in the water samples. The lowest nematode abundance in sediment samples and the lowest NCR in water samples were both found at the industrial pollution site. Water samples showed positive correlation between the NCR and river pollution index (RPI). Mean maturity indices in sediment samples were inversely correlated with RPI. The pollutant source determined the relationship between NCR and pollution level, while maturity index always showed negative correlation with pollutant level regardless of the pollutant sources. The nematode abundance and its community structure were both reliable bioindicators for monitoring long-term river pollution in both qualitative and quantitative aspects. - Nematode community structure in rivers is related to the contamination source and level.

  20. Assessment of nematode community structure as a bioindicator in river monitoring

    International Nuclear Information System (INIS)

    Wu, H.C.; Chen, P.C.; Tsay, T.T.

    2010-01-01

    Nematode communities from river water and sediments were assessed for the abundance, feeding types, maturity indices and nematode channel ratio (NCR). The sampling sites studied included different levels of pollution and contamination from agricultural, industrial and sewage sources. The nematode abundance found in the sediment samples was more than that in the water samples. The lowest nematode abundance in sediment samples and the lowest NCR in water samples were both found at the industrial pollution site. Water samples showed positive correlation between the NCR and river pollution index (RPI). Mean maturity indices in sediment samples were inversely correlated with RPI. The pollutant source determined the relationship between NCR and pollution level, while maturity index always showed negative correlation with pollutant level regardless of the pollutant sources. The nematode abundance and its community structure were both reliable bioindicators for monitoring long-term river pollution in both qualitative and quantitative aspects. - Nematode community structure in rivers is related to the contamination source and level.

  1. Potato cyst nematodes Globodera rostochiensis and Globodera pallida, and their chemoecological interactions with the host plant

    OpenAIRE

    Čepulytė-Rakauskienė, Rasa

    2012-01-01

    Potato cyst nematodes Globodera rostochiensis and Globodera pallida are one of the most important solanaceous plant pests. Identification of potato cyst nematodes species is exposed to morphological similarities and overlapping morphometric measurements between species. Only modern molecular techniques allow more accurate identification of potato cyst nematode species. Hence, it is important to apply these techniques in order to reliably identify these species in Lithuania. Potato roo...

  2. Control of Root-Knot Nematodes on Tomato by the Endoparasitic Fungus Meria coniospora

    OpenAIRE

    Jansson, Hans-Börje; Jeyaprakash, A.; Zuckerman, Bert M.

    1985-01-01

    The endoparasitic nematophagous fungus Meria coniospora reduced root-knot nematode galling on tomatoes in greenhouse pot trials. The fungus was introduced to pots by addition of conidia at several inoculum levels directly to the soil or addition of nematodes infected with M. coniospora to the soil; both methods reduced root galling by root-knot nematodes. These studies represent a part of a recently initiated effort to evaluate the potential of endoparasitic nematophagous fungi for biocontrol...

  3. Application of PCR-DGGE method for identification of nematode communities in pepper growing soil

    OpenAIRE

    Nguyen, Thi Phuong; Ha, Duy Ngo; Nguyen, Huu Hung; Duong, Duc Hieu

    2017-01-01

    Soil nematodes play an important role in indication for assessing soil environments and ecosystems. Previous studies of nematode community analyses based on molecular identification have shown to be useful for assessing soil environments. Here we applied PCR-DGGE method for molecular analysis of five soil nematode communities (designed as S1 to S5) collected from four provinces in Southeastern Vietnam (Binh Duong, Ba Ria Vung Tau, Binh Phuoc and Dong Nai) based on SSU gene. By sequencing DNA ...

  4. Species discovery and diversity in Lobocriconema (Criconematidae: Nematoda) and related plant-parasitic nematodes from North American ecoregions.

    Science.gov (United States)

    Powers, T O; Bernard, E C; Harris, T; Higgins, R; Olson, M; Olson, S; Lodema, M; Matczyszyn, J; Mullin, P; Sutton, L; Powers, K S

    2016-03-03

    There are many nematode species that, following formal description, are seldom mentioned again in the scientific literature. Lobocriconema thornei and L. incrassatum are two such species, described from North American forests, respectively 37 and 49 years ago. In the course of a 3-year nematode biodiversity survey of North American ecoregions, specimens resembling Lobocriconema species appeared in soil samples from both grassland and forested sites. Using a combination of molecular and morphological analyses, together with a set of species delimitation approaches, we have expanded the known range of these species, added to the species descriptions, and discovered a related group of species that form a monophyletic group with the two described species. In this study, 148 specimens potentially belonging to the genus Lobocriconema were isolated from soil, individually measured, digitally imaged, and DNA barcoded using a 721 bp region of cytochrome oxidase subunit 1 (COI). One-third of the specimens were also analyzed using amplified DNA from the 3' region of the small subunit ribosomal RNA gene (18SrDNA) and the adjacent first internal transcribed spacer (ITS1). Eighteen mitochondrial haplotype groups, falling into four major clades, were identified by well-supported nodes in Bayesian and maximum likelihood trees and recognized as distinct lineages by species delimitation metrics. Discriminant function analysis of a set of morphological characters indicated that the major clades in the dataset possessed a strong morphological signal that decreased in comparisons of haplotype groups within clades. Evidence of biogeographic and phylogeographic patterns was apparent in the dataset. COI haplotype diversity was high in the southern Appalachian Mountains and Gulf Coast states and lessened in northern temperate forests. Lobocriconema distribution suggests the existence of phylogeographic patterns associated with recolonization of formerly glaciated regions by eastern

  5. IMMUNE REGULATING ES-PRODUCTS IN PARASITIC NEMATODES

    DEFF Research Database (Denmark)

    Bahlool, Qusay Zuhair Mohammad; Buchmann, Kurt; Kania, Per Walter

    work elucidates the effect of ES substances on the fish immune system by measuring immune gene expression in spleen and liver of rainbow trout (Oncorhynchus mykiss) injected intraperitoneally with ES products isolated from A. simplex third stage larvae. The overall gene expression profile of exposed...... fish showed a generalized down-regulation of the immune genes tested, suggesting a role of ES proteins in minimizing the immune reaction of rainbow trout against invading nematodes. We also tested the enzymatic activity of the ES proteins and found that lipase, esterase lipase, valine and cysteine...... arylamidases, naphthol-AS-BI-phosphohydrolase and a-galactosidase activities were present in the ES solution. This type of hydrolytic enzyme activity may play a role in nematode penetration of host tissue. Based on the notion that A. simplex ES-proteins may have an immune-depressive effect, it could also...

  6. Nematodes Parasites of Teiid Lizards from the Brazilian Amazon Rainforest.

    Science.gov (United States)

    Macedo, L C; Gardner, S L; Melo, F T V; Giese, E G; Santos, J N

    2017-04-01

    This study presents the helminth composition and parameters of infection by several species of nematodes in teiid lizards, Ameiva ameiva ameiva (Linnaeus, 1758), Cnemidophorus cryptus Cole and Dessauer, 1993, and Kentropyx calcarata Spix, 1825 from the Brazilian Amazonian Rainforest. The population of lizards studied were parasitized by 6 species of Phylum Nemata including: Spinicauda spinicauda (Olfers, 1919), Parapharyngodon alvarengai Freitas, 1957, Physaloptera sp. (adults), Physaloptera sp. (larvae), Piratuba digiticauda Lent and Freitas, 1941, and Anisakidae (larvae). The overall prevalence was 66.17% and the mean intensity of infection was 19.40 ± 25.48. The association between the body-length of lizards and the abundance and richness of parasitic nematodes was statistically significant only in Ameiva a. ameiva. A new host record is reported here with 1 specimen of the family Anasakidae in Ameiva a. ameiva. Both S. spinicauda and Physaloptera sp. represent new records from C. cryptus.

  7. Surface micro topography replication in injection moulding

    DEFF Research Database (Denmark)

    Arlø, Uffe Rolf

    Thermoplastic injection moulding is a widely used industrial process that involves surface generation by replication. The surface topography of injection moulded plastic parts can be important for aesthetical or technical reasons. With the emergence of microengineering and nanotechnology additional...... importance of surface topography follows. In general the replication is not perfect and the topography of the plastic part differs from the inverse topography of the mould cavity. It is desirable to be able to control the degree of replication perfection or replication quality. This requires an understanding...... of the physical mechanisms of replication. Such understanding can lead to improved process design and facilitate in-line process quality control with respect to surface properties. The purpose of the project is to identify critical factors that affect topography replication quality and to obtain an understanding...

  8. New host records of the nematode Gnathostoma sp. in Mexico.

    Science.gov (United States)

    León-Règagnon, Virginia; Osorio-Sarabia, David; García-Prieto, Luis; Lamothe-Argumedo, Rafael; Bertoni-Ruiz, Florencia; Oceguera-Figueroa, Alejandro

    2005-03-01

    Gnathostomiasis is an emerging zoonosis in Mexico. However, for most endemic zones, the source of human infection has not been established. During 2000-2003, we investigated 2168 vertebrates (2047 fish, 31 amphibians, 4 reptiles, 19 birds and 67 mammals) from 39 localities distributed in nine states. We registered 7 vertebrate species as new hosts for Gnathostoma, and 22 new locality records for this nematode.

  9. Chemotaxis-defective mutants of the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Dusenbery, D B; Sheridan, R E; Russell, R L

    1975-06-01

    The technique of countercurrent separation has been used to isolate 17 independent chemotaxis-defective mutants of the nematode Caenorhabditis elegans. The mutants, selected to be relatively insensitive to the normally attractive salt NaCl, show varying degrees of residual sensitivity; some are actually weakly repelled by NaCl. The mutants are due to single gene defects, are autosomal and recessive, and identify at least five complementation groups.

  10. In vitro variation of glycogen content in three sheep nematodes.

    Science.gov (United States)

    Premvati, G; Chopra, A K

    1979-06-01

    In vitro variation of glycogen content under aerobic conditions was measured on fresh weight basis in 3 sheep nematodes inhabiting different niches; Haemonchus contortus, Oesophagostomum columbianum and Trichuris ovis. The parasites were saparated into species and then sexes and starved for varying periods of time up to 24 h in glucose-free physiological saline. The differences between females and males and among the species with respect to glycogen content and its rate of change with time are discussed.

  11. Replicating chromatin: a tale of histones

    DEFF Research Database (Denmark)

    Groth, Anja

    2009-01-01

    Chromatin serves structural and functional roles crucial for genome stability and correct gene expression. This organization must be reproduced on daughter strands during replication to maintain proper overlay of epigenetic fabric onto genetic sequence. Nucleosomes constitute the structural...... framework of chromatin and carry information to specify higher-order organization and gene expression. When replication forks traverse the chromosomes, nucleosomes are transiently disrupted, allowing the replication machinery to gain access to DNA. Histone recycling, together with new deposition, ensures...

  12. Utilization of computer processed high definition video imaging for measuring motility of microscopic nematode stages on a quantitative scale: "The Worminator".

    Science.gov (United States)

    Storey, Bob; Marcellino, Chris; Miller, Melissa; Maclean, Mary; Mostafa, Eman; Howell, Sue; Sakanari, Judy; Wolstenholme, Adrian; Kaplan, Ray

    2014-12-01

    A major hindrance to evaluating nematode populations for anthelmintic resistance, as well as for screening existing drugs, new compounds, or bioactive plant extracts for anthelmintic properties, is the lack of an efficient, objective, and reproducible in vitro assay that is adaptable to multiple life stages and parasite genera. To address this need we have developed the "Worminator" system, which objectively and quantitatively measures the motility of microscopic stages of parasitic nematodes. The system is built around the computer application "WormAssay", developed at the Center for Discovery and Innovation in Parasitic Diseases at the University of California, San Francisco. WormAssay was designed to assess motility of macroscopic parasites for the purpose of high throughput screening of potential anthelmintic compounds, utilizing high definition video as an input to assess motion of adult stage (macroscopic) parasites (e.g. Brugia malayi). We adapted this assay for use with microscopic parasites by modifying the software to support a full frame analysis mode that applies the motion algorithm to the entire video frame. Thus, the motility of all parasites in a given well are recorded and measured simultaneously. Assays performed on third-stage larvae (L3) of the bovine intestinal nematode Cooperia spp., as well as microfilariae (mf) of the filarioid nematodes B. malayi and Dirofilaria immitis, yielded reproducible dose responses using the macrocyclic lactones ivermectin, doramectin, and moxidectin, as well as the nicotinic agonists, pyrantel, oxantel, morantel, and tribendimidine. This new computer based-assay is simple to use, requires minimal new investment in equipment, is robust across nematode genera and developmental stage, and does not require subjective scoring of motility by an observer. Thus, the "Worminator" provides a relatively low-cost platform for developing genera- and stage-specific assays with high efficiency and reproducibility, low labor input

  13. Utilization of computer processed high definition video imaging for measuring motility of microscopic nematode stages on a quantitative scale: “The Worminator”

    Directory of Open Access Journals (Sweden)

    Bob Storey

    2014-12-01

    Full Text Available A major hindrance to evaluating nematode populations for anthelmintic resistance, as well as for screening existing drugs, new compounds, or bioactive plant extracts for anthelmintic properties, is the lack of an efficient, objective, and reproducible in vitro assay that is adaptable to multiple life stages and parasite genera. To address this need we have developed the “Worminator” system, which objectively and quantitatively measures the motility of microscopic stages of parasitic nematodes. The system is built around the computer application “WormAssay”, developed at the Center for Discovery and Innovation in Parasitic Diseases at the University of California, San Francisco. WormAssay was designed to assess motility of macroscopic parasites for the purpose of high throughput screening of potential anthelmintic compounds, utilizing high definition video as an input to assess motion of adult stage (macroscopic parasites (e.g. Brugia malayi. We adapted this assay for use with microscopic parasites by modifying the software to support a full frame analysis mode that applies the motion algorithm to the entire video frame. Thus, the motility of all parasites in a given well are recorded and measured simultaneously. Assays performed on third-stage larvae (L3 of the bovine intestinal nematode Cooperia spp., as well as microfilariae (mf of the filarioid nematodes B. malayi and Dirofilaria immitis, yielded reproducible dose responses using the macrocyclic lactones ivermectin, doramectin, and moxidectin, as well as the nicotinic agonists, pyrantel, oxantel, morantel, and tribendimidine. This new computer based-assay is simple to use, requires minimal new investment in equipment, is robust across nematode genera and developmental stage, and does not require subjective scoring of motility by an observer. Thus, the “Worminator” provides a relatively low-cost platform for developing genera- and stage-specific assays with high efficiency and

  14. Functional analysis of pathogenicity proteins of the potato cyst nematode Globodera rostochiensis using RNAi.

    Science.gov (United States)

    Chen, Qing; Rehman, S; Smant, G; Jones, John T

    2005-07-01

    RNA interference (RNAi) has been used widely as a tool for examining gene function and a method that allows its use with plant-parasitic nematodes recently has been described. Here, we use a modified method to analyze the function of secreted beta-1,4, endoglucanases of the potato cyst nematode Globodera rostochiensis, the first in vivo functional analysis of a pathogenicity protein of a plant-parasitic nematode. Knockout of the beta-1,4, endoglucanases reduced the ability of the nematodes to invade roots. We also use RNAi to show that gr-ams-1, a secreted protein of the main sense organs (the amphids), is essential for host location.

  15. Nematode-bacterium symbioses--cooperation and conflict revealed in the "omics" age.

    Science.gov (United States)

    Murfin, Kristen E; Dillman, Adler R; Foster, Jeremy M; Bulgheresi, Silvia; Slatko, Barton E; Sternberg, Paul W; Goodrich-Blair, Heidi

    2012-08-01

    Nematodes are ubiquitous organisms that have a significant global impact on ecosystems, economies, agriculture, and human health. The applied importance of nematodes and the experimental tractability of many species have promoted their use as models in various research areas, including developmental biology, evolutionary biology, ecology, and animal-bacterium interactions. Nematodes are particularly well suited for the investigation of host associations with bacteria because all nematodes have interacted with bacteria during their evolutionary history and engage in a variety of association types. Interactions between nematodes and bacteria can be positive (mutualistic) or negative (pathogenic/parasitic) and may be transient or stably maintained (symbiotic). Furthermore, since many mechanistic aspects of nematode-bacterium interactions are conserved, their study can provide broader insights into other types of associations, including those relevant to human diseases. Recently, genome-scale studies have been applied to diverse nematode-bacterial interactions and have helped reveal mechanisms of communication and exchange between the associated partners. In addition to providing specific information about the system under investigation, these studies also have helped inform our understanding of genome evolution, mutualism, and innate immunity. In this review we discuss the importance and diversity of nematodes, "omics"' studies in nematode-bacterial systems, and the wider implications of the findings.

  16. Adhering Pasteuria penetrans endospores affect movements of root-knot nematode juveniles

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    Ioannis VAGELAS

    2013-01-01

    Full Text Available Pasteuria penetrans is a biological control agent of root-knot nematodes (Meloidogyne spp., preventing root invasion by second-stage juveniles (J2s, and eventually causing females sterility and death. greatest control effects for P. penetrans depend on the numbers of endospores attached to nematode cuticles. a method based on digital image analysis was used to record the effects of endospore attachment on the movements of juvenile root-knot nematodes, using a model based on the centroid point. Data showed that the numbers of endospores attached to the cuticle influenced nematode movement. At high endospore attachment levels (20‒30 per J2, nematodes did not show directional movement, whereas nematodes encumbered with five to eight spores showed limited directional movement, compared to those without endospores. nematode cephalic region turns were modelled using a markov chain, showing that P. penetrans endospores affected movements. Less nematodes invaded and established on tomato root systems when encumbered with low (five to eight or high numbers (20‒30 of P. penetrans endospores, compared with unencumbered nematodes.

  17. The importance, biology and management of cereal cyst nematodes (Heterodera spp.

    Directory of Open Access Journals (Sweden)

    F. Mokrini

    2018-01-01

    Full Text Available Cereals are exposed to biotic and abiotic stresses. Among the biotic stresses, plant-parasitic nematodes play an important role in decreasing crop yield. Cereal cyst nematodes (CCNs are known to be a major constraint to wheat production in several parts of the world. Significant economic losses due to CCNs have been reported. Recognition and identification of CCNs are the first steps in nematode management. This paper reviews the current distribution of CCNs in different parts of the world and the recent advances in nematode identification. The different approaches for managing CCNs are also discussed.

  18. Complex Dynamic Development of Poliovirus Membranous Replication Complexes

    Science.gov (United States)

    Nair, Vinod; Hansen, Bryan T.; Hoyt, Forrest H.; Fischer, Elizabeth R.; Ehrenfeld, Ellie

    2012-01-01

    Replication of all positive-strand RNA viruses is intimately associated with membranes. Here we utilize electron tomography and other methods to investigate the remodeling of membranes in poliovirus-infected cells. We found that the viral replication structures previously described as “vesicles” are in fact convoluted, branching chambers with complex and dynamic morphology. They are likely to originate from cis-Golgi membranes and are represented during the early stages of infection by single-walled connecting and branching tubular compartments. These early viral organelles gradually transform into double-membrane structures by extension of membranous walls and/or collapsing of the luminal cavity of the single-membrane structures. As the double-membrane regions develop, they enclose cytoplasmic material. At this stage, a continuous membranous structure may have double- and single-walled membrane morphology at adjacent cross-sections. In the late stages of the replication cycle, the structures are represented mostly by double-membrane vesicles. Viral replication proteins, double-stranded RNA species, and actively replicating RNA are associated with both double- and single-membrane structures. However, the exponential phase of viral RNA synthesis occurs when single-membrane formations are predominant in the cell. It has been shown previously that replication complexes of some other positive-strand RNA viruses form on membrane invaginations, which result from negative membrane curvature. Our data show that the remodeling of cellular membranes in poliovirus-infected cells produces structures with positive curvature of membranes. Thus, it is likely that there is a fundamental divergence in the requirements for the supporting cellular membrane-shaping machinery among different groups of positive-strand RNA viruses. PMID:22072780

  19. A novel bacterial symbiont in the nematode Spirocerca lupi

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    Gottlieb Yuval

    2012-07-01

    Full Text Available Abstract Background The parasitic nematode Spirocerca lupi (Spirurida: Thelaziidae, the canine esophageal worm, is the causative agent of spirocercosis, a disease causing morbidity and mortality in dogs. Spirocerca lupi has a complex life cycle, involving an obligatory coleopteran intermediate host (vector, an optional paratenic host, and a definitive canid host. The diagnosis of spirocercosis is challenging, especially in the early disease stages, when adult worms and clinical signs are absent. Thus, alternative approaches are needed to promote early diagnosis. The interaction between nematodes and their bacterial symbionts has recently become a focus of novel treatment regimens for other helminthic diseases. Results Using 16S rDNA-based molecular methods, here we found a novel bacterial symbiont in S. lupi that is closely related to Comamonas species (Brukholderiales: Comamonadaceae of the beta-proteobacteria. Its DNA was detected in eggs, larvae and adult stages of S. lupi. Using fluorescent in situ hybridization technique, we localized Comamonas sp. to the gut epithelial cells of the nematode larvae. Specific PCR enabled the detection of this symbiont's DNA in blood obtained from dogs diagnosed with spirocercosis. Conclusions The discovery of a new Comamonas sp. in S. lupi increase the complexity of the interactions among the organisms involved in this system, and may open innovative approaches for diagnosis and control of spirocercosis in dogs.

  20. Origanum vulgare (Lamiaceae OVICIDAL POTENTIAL ON GASTROINTESTINAL NEMATODES OF CATTLE

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    Luciana Laitano Dias de Castro

    2013-12-01

    Full Text Available Due to anthelmintic resistance in nematodes, several research studies have been developed seeking control alternatives to these parasites. This study evaluated the in vitro action of Origanum vulgare on gastrointestinal nematode eggs of cattle. In order to evaluate the ability to inhibit egg hatch, different dried leaves extracts of this plant were tested, such as dye, hydroalcoholic and aqueous extracts at concentrations varying from 0.62 to 80 mg/mL. Each assay was accompanied by control containing levamisole hydrochloride (0.2 mg/mL, distilled water and 70 ºGL grain alcohol at the same concentration of the extracts. Test results showed that the different O. vulgare extracts inhibited egg hatch of cattle gastrointestinal nematodes at a percentage that varied from 8.8 to 100%; dye and hydroalcoholic extract were the most promising inhibitors. In view of this ovicidal property, O. vulgare may be an important source of viable antiparasitic compounds for nematodiosis control in ruminants.

  1. A nematode that can manipulate the behaviour of slugs.

    Science.gov (United States)

    Morris, Alex; Green, Michael; Martin, Hayley; Crossland, Katie; Swaney, William T; Williamson, Sally M; Rae, Robbie

    2018-06-01

    The ability of parasites to manipulate the behaviour of their hosts has evolved multiple times, and has a clear fitness benefit to the parasite in terms of facilitating growth, reproduction and transfer to suitable hosts. The mechanisms by which these behavioural changes are induced are poorly understood, but in many cases parasite manipulation of serotonergic signalling in the host brain is implicated. Here we report that Phasmarhabditis hermaphrodita, a parasite of terrestrial gastropod molluscs, can alter the behaviour of slugs. Uninfected slugs (Deroceras panormitanum, Arion subfuscus and Arion hortensis) avoid areas where P. hermaphrodita is present, but slugs infected with P. hermaphrodita are more likely to be found where the nematodes are present. This ability is specific to P. hermaphrodita and other nematodes (Steinernema carpocapsae and Heterorhabditis bacteriophora) do not induce this behavioural change. To investigate how P. hermaphrodita changes slug behaviour we exposed slugs to fluoxetine (a selective serotonin reuptake inhibitor) and cyproheptadine (a serotonin receptor antagonist). Uninfected slugs fed fluoxetine no longer avoided areas where P. hermaphrodita was present; and conversely, infected slugs fed cyproheptadine showed no increased attraction to areas with nematodes. These findings suggest that a possible mechanism by which P. hermaphrodita is able to manipulate parasite avoidance behaviour in host slugs is by manipulating serotonergic signalling in the brain, and that increased serotonin levels are potentially associated with a reduction in parasite avoidance. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Nematodes from Achatina fulica Bowdich, 1822 (Mollusca: Gastropoda in Argentina

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    Valente R.

    2016-03-01

    Full Text Available The aim of this study is to describe the nematode cysts and larvae found in Achatina fulica, the giant African snail, in the northeast of Argentina. A total of 373 snails were collected from the cities of Puerto Iguazú and Corrientes. Cysts (N= 2958 containing nematodes identified as L3 Strongyluris sp. were found in the mantle cavity of 87 snails from Puerto Iguazú City (Prevalence 23 %; Mean Intensity= 34; Mean Abundance= 8. The shell size correlated with prevalence, mean intensity and mean abundance (p < 0.05 indicating that there is an exposure-infection constant rather than an accidental one. In other hand, the absence of infection in the smallest shell size suggests a threshold of size to be infected. Taking into account that there exist records of A. fulica infected by nematodes of medical and veterinary importance such as Angiostrongylus and Aelurostrongylus in some Brazilian states near Puerto Iguazú, we emphasize the need for snail surveillance.

  3. Sex-specific lifespan and its evolution in nematodes.

    Science.gov (United States)

    Ancell, Henry; Pires-daSilva, Andre

    2017-10-01

    Differences between sexes of the same species in lifespan and aging rate are widespread. While the proximal and evolutionary causes of aging are well researched, the factors that contribute to sex differences in these traits have been less studied. The striking diversity of nematodes provides ample opportunity to study variation in sex-specific lifespan patterns associated with shifts in life history and mating strategy. Although the plasticity of these sex differences will make it challenging to generalize from invertebrate to vertebrate systems, studies in nematodes have enabled empirical evaluation of predictions regarding the evolution of lifespan. These studies have highlighted how natural and sexual selection can generate divergent patterns of lifespan if the sexes are subject to different rates or sources of mortality, or if trade-offs between complex traits and longevity are resolved differently in each sex. Here, we integrate evidence derived mainly from nematodes that addresses the molecular and evolutionary basis of sex-specific aging and lifespan. Ultimately, we hope to generate a clearer picture of current knowledge in this area, and also highlight the limitations of our understanding. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Functional diversification of Argonautes in nematodes: an expanding universe.

    Science.gov (United States)

    Buck, Amy H; Blaxter, Mark

    2013-08-01

    In the last decade, many diverse RNAi (RNA interference) pathways have been discovered that mediate gene silencing at epigenetic, transcriptional and post-transcriptional levels. The diversity of RNAi pathways is inherently linked to the evolution of Ago (Argonaute) proteins, the central protein component of RISCs (RNA-induced silencing complexes). An increasing number of diverse Agos have been identified in different species. The functions of most of these proteins are not yet known, but they are generally assumed to play roles in development, genome stability and/or protection against viruses. Recent research in the nematode Caenorhabditis elegans has expanded the breadth of RNAi functions to include transgenerational epigenetic memory and, possibly, environmental sensing. These functions are inherently linked to the production of secondary siRNAs (small interfering RNAs) that bind to members of a clade of WAGOs (worm-specific Agos). In the present article, we review briefly what is known about the evolution and function of Ago proteins in eukaryotes, including the expansion of WAGOs in nematodes. We postulate that the rapid evolution of WAGOs enables the exceptional functional plasticity of nematodes, including their capacity for parasitism.

  5. Enzymatic recognition of DNA replication origins

    International Nuclear Information System (INIS)

    Stayton, M.M.; Bertsch, L.; Biswas, S.

    1983-01-01

    In this paper we discuss the process of recognition of the complementary-strand origin with emphasis on RNA polymerase action in priming M13 DNA replication, the role of primase in G4 DNA replication, and the function of protein n, a priming protein, during primosome assembly. These phage systems do not require several of the bacterial DNA replication enzymes, particularly those involved in the regulation of chromosome copy number of the initiatiion of replication of duplex DNA. 51 references, 13 figures, 1 table

  6. Traditional and molecular detection methods reveal intense interguild competition and other multitrophic interactions associated with native entomopathogenic nematodes in Swiss tillage soils

    Czech Academy of Sciences Publication Activity Database

    Campos-Herrera, R.; Jaffuel, G.; Chiriboga, X.; Blanco-Pérez, R.; Fesselet, M.; Půža, Vladimír; Mascher, F.; Turlings, T. C. J.

    2015-01-01

    Roč. 389, 1-2 (2015), s. 237-255 ISSN 0032-079X Grant - others:Swiss National Science Foundation(CH) 143065 Institutional support: RVO:60077344 Keywords : entomopathogenic nematodes * annual crops * soil food web Subject RIV: EH - Ecology, Behaviour Impact factor: 2.969, year: 2015 http://link.springer.com/article/10.1007%2Fs11104-014-2358-4

  7. Phylogenetic relationships of some spirurine nematodes (Nematoda: Chromadorea: Rhabditida: Spirurina) parasitic in fishes inferred from SSU rRNA gene sequences.

    Science.gov (United States)

    Cernotíková, Eva; Horák, Ales; Moravec, Frantisek

    2011-06-01

    Abstract: Small subunit rRNA sequences were obtained from 38 representatives mainly of the nematode orders Spirurida (Camallanidae, Cystidicolidae, Daniconematidae, Philometridae, Physalopteridae, Rhabdochonidae, Skrjabillanidae) and, in part, Ascaridida (Anisakidae, Cucullanidae, Quimperiidae). The examined nematodes are predominantly parasites of fishes. Their analyses provided well-supported trees allowing the study ofphylogenetic relationships among some spirurine nematodes. The present results support the placement of Cucullanidae at the base of the suborder Spirurina and, based on the position of the genus Philonema (subfamily Philoneminae) forming a sister group to Skrjabillanidae (thus Philoneminae should be elevated to Philonemidae), the paraphyly of the Philometridae. Comparison of a large number of sequences of representatives of the latter family supports the paraphyly of the genera Philometra, Philometroides and Dentiphilometra. The validity of the newly included genera Afrophilometra and Caranginema is not supported. These results indicate geographical isolation has not been the cause of speciation in this parasite group and no coevolution with fish hosts is apparent. On the contrary, the group of South-American species ofAlinema, Nilonema and Rumai is placed in an independent branch, thus markedly separated from other family members. Molecular data indicate that the skrjabillanid subfamily Esocineminae (represented by Esocinema bohemicum) should be either elevated to the rank of an independent family or Daniconematidae (Mexiconema africanum) should be decreased to Daniconematinae and transferred to the family Skrjabillanidae. Camallanid genera Camallanus and Procamallanus, as well as the subgenera Procamallanus and Spirocamallanus are confirmed to be paraphyletic. Paraphyly has also been found within Filarioidea, Habronematoidea and Thelazioidea and in Cystidicolidae, Physalopteridae and Thelaziidae. The results of the analyses also show that

  8. Replicative Intermediates of Human Papillomavirus Type 11 in Laryngeal Papillomas: Site of Replication Initiation and Direction of Replication

    Science.gov (United States)

    Auborn, K. J.; Little, R. D.; Platt, T. H. K.; Vaccariello, M. A.; Schildkraut, C. L.

    1994-07-01

    We have examined the structures of replication intermediates from the human papillomavirus type 11 genome in DNA extracted from papilloma lesions (laryngeal papillomas). The sites of replication initiation and termination utilized in vivo were mapped by using neutral/neutral and neutral/alkaline two-dimensional agarose gel electrophoresis methods. Initiation of replication was detected in or very close to the upstream regulatory region (URR; the noncoding, regulatory sequences upstream of the open reading frames in the papillomavirus genome). We also show that replication forks proceed bidirectionally from the origin and converge 180circ opposite the URR. These results demonstrate the feasibility of analysis of replication of viral genomes directly from infected tissue.

  9. Activation of human herpesvirus replication by apoptosis.

    Science.gov (United States)

    Prasad, Alka; Remick, Jill; Zeichner, Steven L

    2013-10-01

    A central feature of herpesvirus biology is the ability of herpesviruses to remain latent within host cells. Classically, exposure to inducing agents, like activating cytokines or phorbol esters that stimulate host cell signal transduction events, and epigenetic agents (e.g., butyrate) was thought to end latency. We recently showed that Kaposi's sarcoma-associated herpesvirus (KSHV, or human herpesvirus-8 [HHV-8]) has another, alternative emergency escape replication pathway that is triggered when KSHV's host cell undergoes apoptosis, characterized by the lack of a requirement for the replication and transcription activator (RTA) protein, accelerated late gene kinetics, and production of virus with decreased infectivity. Caspase-3 is necessary and sufficient to initiate the alternative replication program. HSV-1 was also recently shown to initiate replication in response to host cell apoptosis. These observations suggested that an alternative apoptosis-triggered replication program might be a general feature of herpesvirus biology and that apoptosis-initiated herpesvirus replication may have clinical implications, particularly for herpesviruses that almost universally infect humans. To explore whether an alternative apoptosis-initiated replication program is a common feature of herpesvirus biology, we studied cell lines latently infected with Epstein-Barr virus/HHV-4, HHV-6A, HHV-6B, HHV-7, and KSHV. We found that apoptosis triggers replication for each HHV studied, with caspase-3 being necessary and sufficient for HHV replication. An alternative apoptosis-initiated replication program appears to be a common feature of HHV biology. We also found that commonly used cytotoxic chemotherapeutic agents activate HHV replication, which suggests that treatments that promote apoptosis may lead to activation of latent herpesviruses, with potential clinical significance.

  10. Bioinformatic prediction of arthropod/nematode-like peptides in non-arthropod, non-nematode members of the Ecdysozoa.

    Science.gov (United States)

    Christie, Andrew E; Nolan, Daniel H; Garcia, Zachery A; McCoole, Matthew D; Harmon, Sarah M; Congdon-Jones, Benjamin; Ohno, Paul; Hartline, Niko; Congdon, Clare Bates; Baer, Kevin N; Lenz, Petra H

    2011-02-01

    The Onychophora, Priapulida and Tardigrada, along with the Arthropoda, Nematoda and several other small phyla, form the superphylum Ecdysozoa. Numerous peptidomic studies have been undertaken for both the arthropods and nematodes, resulting in the identification of many peptides from each group. In contrast, little is known about the peptides used as paracrines/hormones by species from the other ecdysozoan taxa. Here, transcriptome mining and bioinformatic peptide prediction were used to identify peptides in members of the Onychophora, Priapulida and Tardigrada, the only non-arthropod, non-nematode members of the Ecdysozoa for which there are publicly accessible expressed sequence tags (ESTs). The extant ESTs for each phylum were queried using 106 arthropod/nematode peptide precursors. Transcripts encoding calcitonin-like diuretic hormone and pigment-dispersing hormone (PDH) were identified for the onychophoran Peripatopsis sedgwicki, with transcripts encoding C-type allatostatin (C-AST) and FMRFamide-like peptide identified for the priapulid Priapulus caudatus. For the Tardigrada, transcripts encoding members of the A-type allatostatin, C-AST, insect kinin, orcokinin, PDH and tachykinin-related peptide families were identified, all but one from Hypsibius dujardini (the exception being a Milnesium tardigradum orcokinin-encoding transcript). The proteins deduced from these ESTs resulted in the prediction of 48 novel peptides, six onychophoran, eight priapulid and 34 tardigrade, which are the first described from these phyla. Copyright © 2010 Elsevier Inc. All rights reserved.

  11. Anisakid nematodes (Nematoda: Anisakidae) from the marine fishes Plectropomus laevis Lace´pe`de (Serranidae) and Sphyraena qenie Klunzinger (Sphyraenidae) off New Caledonia, including two new species of Hysterothylacium Ward & Magath, 1917

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Justine, J.-L.

    2015-01-01

    Roč. 92, č. 3 (2015), s. 181-195 ISSN 0165-5752 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:60077344 Keywords : parasitic nematode * Anisakidae * New Caledonia Subject RIV: EG - Zoology Impact factor: 1.316, year: 2015

  12. DNA replication and cancer: From dysfunctional replication origin activities to therapeutic opportunities.

    Science.gov (United States)

    Boyer, Anne-Sophie; Walter, David; Sørensen, Claus Storgaard

    2016-06-01

    A dividing cell has to duplicate its DNA precisely once during the cell cycle to preserve genome integrity avoiding the accumulation of genetic aberrations that promote diseases such as cancer. A large number of endogenous impacts can challenge DNA replication and cells harbor a battery of pathways to promote genome integrity during DNA replication. This includes suppressing new replication origin firing, stabilization of replicating forks, and the safe restart of forks to prevent any loss of genetic information. Here, we describe mechanisms by which oncogenes can interfere with DNA replication thereby causing DNA replication stress and genome instability. Further, we describe cellular and systemic responses to these insults with a focus on DNA replication restart pathways. Finally, we discuss the therapeutic potential of exploiting intrinsic replicative stress in cancer cells for targeted therapy. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Professional nursing burnout and irrational thinking: a replication study.

    Science.gov (United States)

    Balevre, Park S; Cassells, Julie; Buzaianu, Elena

    2012-01-01

    This expanded (n = 648) replication study examines job-related burnout in practicing nurses in relation to five maladaptive thinking patterns at eight northeast Florida hospitals. Data supported the hypothesis that maladaptive thinking patterns may be related to nurses' burnout thoughts and behaviors. The focus of this research spotlights the individual nurse's thoughts, emotions, and actions and suggests that these burnout tendencies can be mitigated if not changed.

  14. The Complex Cell Wall Composition of Syncytia Induced by Plant Parasitic Cyst Nematodes Reflects Both Function and Host Plant

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    Li Zhang

    2017-06-01

    Full Text Available Plant–parasitic cyst nematodes induce the formation of specialized feeding structures, syncytia, within their host roots. These unique plant organs serve as the sole nutrient resource for development and reproduction throughout the biotrophic interaction. The multinucleate syncytium, which arises through local dissolution of cell walls and protoplast fusion of multiple adjacent cells, has dense cytoplasm containing numerous organelles, surrounded by thickened outer cell walls that must withstand high turgor pressure. However, little is known about how the constituents of the syncytial cell wall and their conformation support its role during nematode parasitism. We used a set of monoclonal antibodies, targeted to a range of plant cell wall components, to reveal the microstructures of syncytial cell walls induced by four of the most economically important cyst nematode species, Globodera pallida, Heterodera glycines, Heterodera avenae and Heterodera filipjevi, in their respective potato, soybean, and spring wheat host roots. In situ fluorescence analysis revealed highly similar cell wall composition of syncytia induced by G. pallida and H. glycines. Both consisted of abundant xyloglucan, methyl-esterified homogalacturonan and pectic arabinan. In contrast, the walls of syncytia induced in wheat roots by H. avenae and H. filipjevi contain little xyloglucan but are rich in feruloylated xylan and arabinan residues, with variable levels of mixed-linkage glucan. The overall chemical composition of syncytial cell walls reflected the general features of root cell walls of the different host plants. We relate specific components of syncytial cell walls, such as abundant arabinan, methyl-esterification status of pectic homogalacturonan and feruloylation of xylan, to their potential roles in forming a network to support both the strength and flexibility required for syncytium function.

  15. The Complex Cell Wall Composition of Syncytia Induced by Plant Parasitic Cyst Nematodes Reflects Both Function and Host Plant.

    Science.gov (United States)

    Zhang, Li; Lilley, Catherine J; Imren, Mustafa; Knox, J Paul; Urwin, Peter E

    2017-01-01

    Plant-parasitic cyst nematodes induce the formation of specialized feeding structures, syncytia, within their host roots. These unique plant organs serve as the sole nutrient resource for development and reproduction throughout the biotrophic interaction. The multinucleate syncytium, which arises through local dissolution of cell walls and protoplast fusion of multiple adjacent cells, has dense cytoplasm containing numerous organelles, surrounded by thickened outer cell walls that must withstand high turgor pressure. However, little is known about how the constituents of the syncytial cell wall and their conformation support its role during nematode parasitism. We used a set of monoclonal antibodies, targeted to a range of plant cell wall components, to reveal the microstructures of syncytial cell walls induced by four of the most economically important cyst nematode species, Globodera pallida , Heterodera glycines , Heterodera avenae and Heterodera filipjevi , in their respective potato, soybean, and spring wheat host roots. In situ fluorescence analysis revealed highly similar cell wall composition of syncytia induced by G. pallida and H. glycines . Both consisted of abundant xyloglucan, methyl-esterified homogalacturonan and pectic arabinan. In contrast, the walls of syncytia induced in wheat roots by H. avenae and H. filipjevi contain little xyloglucan but are rich in feruloylated xylan and arabinan residues, with variable levels of mixed-linkage glucan. The overall chemical composition of syncytial cell walls reflected the general features of root cell walls of the different host plants. We relate specific components of syncytial cell walls, such as abundant arabinan, methyl-esterification status of pectic homogalacturonan and feruloylation of xylan, to their potential roles in forming a network to support both the strength and flexibility required for syncytium function.

  16. Soil nematode assemblages as bioindicators of radiation impact in the Chernobyl Exclusion Zone

    International Nuclear Information System (INIS)

    Lecomte-Pradines, C.; Bonzom, J.-M.; Della-Vedova, C.; Beaugelin-Seiller, K.; Villenave, C.; Gaschak, S.; Coppin, F.; Dubourg, N.; Maksimenko, A.; Adam-Guillermin, C.; Garnier-Laplace, J.

    2014-01-01

    In radioecology, the need to understand the long-term ecological effects of radioactive contamination has been emphasised. This requires that the health of field populations is evaluated and linked to an accurate estimate of received radiological dose. The aim of the present study was to assess the effects of current radioactive contamination on nematode assemblages at sites affected by the fallout from the Chernobyl accident. First, we estimated the total dose rates (TDRs) absorbed by nematodes, from measured current soil activity concentrations, Dose Conversion Coefficients (DCCs, calculated using EDEN software) and soil-to-biota concentration ratios (from the ERICA tool database). The impact of current TDRs on nematode assemblages was then evaluated. Nematodes were collected in spring 2011 from 18 forest sites in the Chernobyl Exclusion Zone (CEZ) with external gamma dose rates, measured using radiophotoluminescent dosimeters, varying from 0.2 to 22 μGy h −1 . These values were one order of magnitude below the TDRs. A majority of bacterial-, plant-, and fungal-feeding nematodes and very few of the disturbance sensitive families were identified. No statistically significant association was observed between TDR values and nematode total abundance or the Shannon diversity index (H′). The Nematode Channel Ratio (which defines the relative abundance of bacterial- versus fungal-feeding nematodes) decreased significantly with increasing TDR, suggesting that radioactive contamination may influence nematode assemblages either directly or indirectly by modifying their food resources. A greater Maturity Index (MI), usually characterising better soil quality, was associated with higher pH and TDR values. These results suggest that in the CEZ, nematode assemblages from the forest sites were slightly impacted by chronic exposure at a predicted TDR of 200 μGy h −1 . This may be imputable to a dominant proportion of pollutant resistant nematodes in all sites. This might

  17. NemaPath: online exploration of KEGG-based metabolic pathways for nematodes

    Directory of Open Access Journals (Sweden)

    Wang Zhengyuan

    2008-11-01

    Full Text Available Abstract Background Nematode.net http://www.nematode.net is a web-accessible resource for investigating gene sequences from parasitic and free-living nematode genomes. Beyond the well-characterized model nematode C. elegans, over 500,000 expressed sequence tags (ESTs and nearly 600,000 genome survey sequences (GSSs have been generated from 36 nematode species as part of the Parasitic Nematode Genomics Program undertaken by the Genome Center at Washington University School of Medicine. However, these sequencing data are not present in most publicly available protein databases, which only include sequences in Swiss-Prot. Swiss-Prot, in turn, relies on GenBank/Embl/DDJP for predicted proteins from complete genomes or full-length proteins. Description Here we present the NemaPath pathway server, a web-based pathway-level visualization tool for navigating putative metabolic pathways for over 30 nematode species, including 27 parasites. The NemaPath approach consists of two parts: 1 a backend tool to align and evaluate nematode genomic sequences (curated EST contigs against the annotated Kyoto Encyclopedia of Genes and Genomes (KEGG protein database; 2 a web viewing application that displays annotated KEGG pathway maps based on desired confidence levels of primary sequence similarity as defined by a user. NemaPath also provides cross-referenced access to nematode genome information provided by other tools available on Nematode.net, including: detailed NemaGene EST cluster information; putative translations; GBrowse EST cluster views; links from nematode data to external databases for corresponding synonymous C. elegans counterparts, subject matches in KEGG's gene database, and also KEGG Ontology (KO identification. Conclusion The NemaPath server hosts metabolic pathway mappings for 30 nematode species and is available on the World Wide Web at http://nematode.net/cgi-bin/keggview.cgi. The nematode source sequences used for the metabolic pathway

  18. Soil nematode assemblages as bioindicators of radiation impact in the Chernobyl Exclusion Zone

    Energy Technology Data Exchange (ETDEWEB)

    Lecomte-Pradines, C., E-mail: catherine.lecomte-pradines@irsn.fr [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LECO, Building 186, Cadarache 13115 Saint Paul lez Durance cedex (France); Bonzom, J.-M. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LECO, Building 186, Cadarache 13115 Saint Paul lez Durance cedex (France); Della-Vedova, C. [Magelis, 6, rue Frederic Mistral, 84160 Cadenet (France); Beaugelin-Seiller, K. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LM2E, Building 159, Cadarache 13115 Saint Paul lez Durance cedex (France); Villenave, C. [ELISOL Environment, Building 12, Campus de la Gaillarde, 2 place Viala, 34060 Montpellier cedex 2 (France); Gaschak, S. [Chernobyl Center for Nuclear Safety, Radioactive Waste and Radioecology, International Radioecology Laboratory, 07100 Slavutych (Ukraine); Coppin, F. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, L2BT, Building 186, Cadarache 13115 Saint Paul lez Durance cedex (France); Dubourg, N. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, GARM Building 186, Cadarache 13115 Saint Paul lez Durance cedex (France); Maksimenko, A. [Chernobyl Center for Nuclear Safety, Radioactive Waste and Radioecology, International Radioecology Laboratory, 07100 Slavutych (Ukraine); Adam-Guillermin, C. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, LECO, Building 186, Cadarache 13115 Saint Paul lez Durance cedex (France); Garnier-Laplace, J. [Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS, Building 159, Cadarache 13115 Saint Paul lez Durance cedex (France)

    2014-08-15

    In radioecology, the need to understand the long-term ecological effects of radioactive contamination has been emphasised. This requires that the health of field populations is evaluated and linked to an accurate estimate of received radiological dose. The aim of the present study was to assess the effects of current radioactive contamination on nematode assemblages at sites affected by the fallout from the Chernobyl accident. First, we estimated the total dose rates (TDRs) absorbed by nematodes, from measured current soil activity concentrations, Dose Conversion Coefficients (DCCs, calculated using EDEN software) and soil-to-biota concentration ratios (from the ERICA tool database). The impact of current TDRs on nematode assemblages was then evaluated. Nematodes were collected in spring 2011 from 18 forest sites in the Chernobyl Exclusion Zone (CEZ) with external gamma dose rates, measured using radiophotoluminescent dosimeters, varying from 0.2 to 22 μGy h{sup −1}. These values were one order of magnitude below the TDRs. A majority of bacterial-, plant-, and fungal-feeding nematodes and very few of the disturbance sensitive families were identified. No statistically significant association was observed between TDR values and nematode total abundance or the Shannon diversity index (H′). The Nematode Channel Ratio (which defines the relative abundance of bacterial- versus fungal-feeding nematodes) decreased significantly with increasing TDR, suggesting that radioactive contamination may influence nematode assemblages either directly or indirectly by modifying their food resources. A greater Maturity Index (MI), usually characterising better soil quality, was associated with higher pH and TDR values. These results suggest that in the CEZ, nematode assemblages from the forest sites were slightly impacted by chronic exposure at a predicted TDR of 200 μGy h{sup −1}. This may be imputable to a dominant proportion of pollutant resistant nematodes in all sites

  19. Soil nematode assemblages as bioindicators of radiation impact in the Chernobyl Exclusion Zone.

    Science.gov (United States)

    Lecomte-Pradines, C; Bonzom, J-M; Della-Vedova, C; Beaugelin-Seiller, K; Villenave, C; Gaschak, S; Coppin, F; Dubourg, N; Maksimenko, A; Adam-Guillermin, C; Garnier-Laplace, J

    2014-08-15

    In radioecology, the need to understand the long-term ecological effects of radioactive contamination has been emphasised. This requires that the health of field populations is evaluated and linked to an accurate estimate of received radiological dose. The aim of the present study was to assess the effects of current radioactive contamination on nematode assemblages at sites affected by the fallout from the Chernobyl accident. First, we estimated the total dose rates (TDRs) absorbed by nematodes, from measured current soil activity concentrations, Dose Conversion Coefficients (DCCs, calculated using EDEN software) and soil-to-biota concentration ratios (from the ERICA tool database). The impact of current TDRs on nematode assemblages was then evaluated. Nematodes were collected in spring 2011 from 18 forest sites in the Chernobyl Exclusion Zone (CEZ) with external gamma dose rates, measured using radiophotoluminescent dosimeters, varying from 0.2 to 22 μGy h(-1). These values were one order of magnitude below the TDRs. A majority of bacterial-, plant-, and fungal-feeding nematodes and very few of the disturbance sensitive families were identified. No statistically significant association was observed between TDR values and nematode total abundance or the Shannon diversity index (H'). The Nematode Channel Ratio (which defines the relative abundance of bacterial- versus fungal-feeding nematodes) decreased significantly with increasing TDR, suggesting that radioactive contamination may influence nematode assemblages either directly or indirectly by modifying their food resources. A greater Maturity Index (MI), usually characterising better soil quality, was associated with higher pH and TDR values. These results suggest that in the CEZ, nematode assemblages from the forest sites were slightly impacted by chronic exposure at a predicted TDR of 200 μGy h(-1). This may be imputable to a dominant proportion of pollutant resistant nematodes in all sites. This might

  20. Nematode community structure along a central Chile margin transect influenced by the oxygen minimum zone

    Science.gov (United States)

    Neira, Carlos; King, Ian; Mendoza, Guillermo; Sellanes, Javier; De Ley, Paul; Levin, Lisa A.

    2013-08-01

    Nematodes are among the metazoans most tolerant of low-oxygen conditions and play major roles in seafloor ecosystem processes. Nematode communities were studied in sediments off Concepción, Central Chile, spanning the outer shelf within the OMZ (122 m) to the mid-lower continental slope (972 m) beneath the OMZ. The total density and biomass of nematodes (core depth 0-10 cm) ranged from 677 to 2006 ind. 10 cm-2, and 168.4 to 506.5 μg DW 10 cm-2, respectively. Among metazoan meiofaunal taxa, nematodes predominated at all sites both in terms of relative abundance (83.7-99.4%) and biomass (53.8-88.1%), followed by copepods, nauplii and polychaetes. Nematodes were represented by 33 genera distributed among 17 families, with densities greatest at low oxygen sites (122-364 m; ~2000 ind. 10 cm-2). Nematode generic and trophic diversity, and individual biomass were lowest, and Rank 1 dominance was highest, at the most oxygen-depleted site (122 m), despite the fact that the organic carbon content of the sediment was maximal at this depth. At the most oxygenated slope sites (827 and 972 m), all of Wieser's nematode feeding groups were represented. In contrast, at the lowest-oxygen site, only selective deposit (bacterial) feeders (1A) were present, indicating a reduction in trophic complexity. A large percentage of nematodes inhabited subsurface sediment layers (>1 cm). At deeper, more oxygenated sites (827 and 972 m), nematode individual biomass increased downcore, while within the OMZ, nematode biomass was low and remained relatively uniform through the sediment column. The concentration of nematodes in deeper sediment layers, the vertical distribution of the feeding groups, as well as the high nutritional quality of the deeper layers, suggest a differential resource partitioning of the food available, which may reduce interspecific competition.

  1. Replication and Robustness in Developmental Research

    Science.gov (United States)

    Duncan, Greg J.; Engel, Mimi; Claessens, Amy; Dowsett, Chantelle J.

    2014-01-01

    Replications and robustness checks are key elements of the scientific method and a staple in many disciplines. However, leading journals in developmental psychology rarely include explicit replications of prior research conducted by different investigators, and few require authors to establish in their articles or online appendices that their key…

  2. Three Conceptual Replication Studies in Group Theory

    Science.gov (United States)

    Melhuish, Kathleen

    2018-01-01

    Many studies in mathematics education research occur with a nonrepresentative sample and are never replicated. To challenge this paradigm, I designed a large-scale study evaluating student conceptions in group theory that surveyed a national, representative sample of students. By replicating questions previously used to build theory around student…

  3. Using Replication Projects in Teaching Research Methods

    Science.gov (United States)

    Standing, Lionel G.; Grenier, Manuel; Lane, Erica A.; Roberts, Meigan S.; Sykes, Sarah J.

    2014-01-01

    It is suggested that replication projects may be valuable in teaching research methods, and also address the current need in psychology for more independent verification of published studies. Their use in an undergraduate methods course is described, involving student teams who performed direct replications of four well-known experiments, yielding…

  4. Dynamic behavior of DNA replication domains

    NARCIS (Netherlands)

    Manders, E. M.; Stap, J.; Strackee, J.; van Driel, R.; Aten, J. A.

    1996-01-01

    Like many nuclear processes, DNA replication takes place in distinct domains that are scattered throughout the S-phase nucleus. Recently we have developed a fluorescent double-labeling procedure that allows us to visualize nascent DNA simultaneously with "newborn" DNA that had replicated earlier in

  5. The Hsk1(Cdc7) replication kinase regulates origin efficiency.

    Science.gov (United States)

    Patel, Prasanta K; Kommajosyula, Naveen; Rosebrock, Adam; Bensimon, Aaron; Leatherwood, Janet; Bechhoefer, John; Rhind, Nicholas

    2008-12-01

    Origins of DNA replication are generally inefficient, with most firing in fewer than half of cell cycles. However, neither the mechanism nor the importance of the regulation of origin efficiency is clear. In fission yeast, origin firing is stochastic, leading us to hypothesize that origin inefficiency and stochasticity are the result of a diffusible, rate-limiting activator. We show that the Hsk1-Dfp1 replication kinase (the fission yeast Cdc7-Dbf4 homologue) plays such a role. Increasing or decreasing Hsk1-Dfp1 levels correspondingly increases or decreases origin efficiency. Furthermore, tethering Hsk1-Dfp1 near an origin increases the efficiency of that origin, suggesting that the effective local concentration of Hsk1-Dfp1 regulates origin firing. Using photobleaching, we show that Hsk1-Dfp1 is freely diffusible in the nucleus. These results support a model in which the accessibility of replication origins to Hsk1-Dfp1 regulates origin efficiency and provides a potential mechanistic link between chromatin structure and replication timing. By manipulating Hsk1-Dfp1 levels, we show that increasing or decreasing origin firing rates leads to an increase in genomic instability, demonstrating the biological importance of appropriate origin efficiency.

  6. Replication initiatives will not salvage the trustworthiness of psychology.

    Science.gov (United States)

    Coyne, James C

    2016-05-31

    Replication initiatives in psychology continue to gather considerable attention from far outside the field, as well as controversy from within. Some accomplishments of these initiatives are noted, but this article focuses on why they do not provide a general solution for what ails psychology. There are inherent limitations to mass replications ever being conducted in many areas of psychology, both in terms of their practicality and their prospects for improving the science. Unnecessary compromises were built into the ground rules for design and publication of the Open Science Collaboration: Psychology that undermine its effectiveness. Some ground rules could actually be flipped into guidance for how not to conduct replications. Greater adherence to best publication practices, transparency in the design and publishing of research, strengthening of independent post-publication peer review and firmer enforcement of rules about data sharing and declarations of conflict of interest would make many replications unnecessary. Yet, it has been difficult to move beyond simple endorsement of these measures to consistent implementation. Given the strong institutional support for questionable publication practices, progress will depend on effective individual and collective use of social media to expose lapses and demand reform. Some recent incidents highlight the necessity of this.

  7. PRC1 Prevents Replication Stress during Chondrogenic Transit Amplification

    Directory of Open Access Journals (Sweden)

    Frank Spaapen

    2017-12-01

    Full Text Available Transit amplification (TA, a state of combined, rapid proliferative expansion and differentiation of stem cell-descendants, remains poorly defined at the molecular level. The Polycomb Repressive Complex 1 (PRC1 protein BMI1 has been localized to TA compartments, yet its exact role in TA is unclear. PRC1 proteins control gene expression, cell proliferation and DNA-damage repair. Coordination of such DNA-templated activities during TA is predicted to be crucial to support DNA replication and differentiation-associated transcriptional programming. We here examined whether chondrogenesis provides a relevant biological context for synchronized coordination of these chromatin-based tasks by BMI1. Taking advantage of a prominently featuring TA-phase during chondrogenesis in vitro and in vivo, we here report that TA is completely dependent on intact PRC1 function. BMI1-depleted chondrogenic progenitors rapidly accumulate double strand DNA breaks during DNA replication, present massive non-H3K27me3-directed transcriptional deregulation and fail to undergo chondrogenic TA. Genome-wide accumulation of Topoisomerase 2α and Geminin suggests a model in which PRC1 synchronizes replication and transcription during rapid chondrogenic progenitor expansion. Our combined data reveals for the first time a vital cell-autonomous role for PRC1 during chondrogenesis. We provide evidence that chondrocyte hyper-replication and hypertrophy represent a unique example of programmed senescence in vivo. These findings provide new perspectives on PRC1 function in development and disease.

  8. Evolution of DNA replication protein complexes in eukaryotes and Archaea.

    Directory of Open Access Journals (Sweden)

    Nicholas Chia

    Full Text Available BACKGROUND: The replication of DNA in Archaea and eukaryotes requires several ancillary complexes, including proliferating cell nuclear antigen (PCNA, replication factor C (RFC, and the minichromosome maintenance (MCM complex. Bacterial DNA replication utilizes comparable proteins, but these are distantly related phylogenetically to their archaeal and eukaryotic counterparts at best. METHODOLOGY/PRINCIPAL FINDINGS: While the structures of each of the complexes do not differ significantly between the archaeal and eukaryotic versions thereof, the evolutionary dynamic in the two cases does. The number of subunits in each complex is constant across all taxa. However, they vary subtly with regard to composition. In some taxa the subunits are all identical in sequence, while in others some are homologous rather than identical. In the case of eukaryotes, there is no phylogenetic variation in the makeup of each complex-all appear to derive from a common eukaryotic ancestor. This is not the case in Archaea, where the relationship between the subunits within each complex varies taxon-to-taxon. We have performed a detailed phylogenetic analysis of these relationships in order to better understand the gene duplications and divergences that gave rise to the homologous subunits in Archaea. CONCLUSION/SIGNIFICANCE: This domain level difference in evolution suggests that different forces have driven the evolution of DNA replication proteins in each of these two domains. In addition, the phylogenies of all three gene families support the distinctiveness of the proposed archaeal phylum Thaumarchaeota.

  9. The Hsk1(Cdc7) Replication Kinase Regulates Origin Efficiency

    Science.gov (United States)

    Patel, Prasanta K.; Kommajosyula, Naveen; Rosebrock, Adam; Bensimon, Aaron; Leatherwood, Janet; Bechhoefer, John

    2008-01-01

    Origins of DNA replication are generally inefficient, with most firing in fewer than half of cell cycles. However, neither the mechanism nor the importance of the regulation of origin efficiency is clear. In fission yeast, origin firing is stochastic, leading us to hypothesize that origin inefficiency and stochasticity are the result of a diffusible, rate-limiting activator. We show that the Hsk1-Dfp1 replication kinase (the fission yeast Cdc7-Dbf4 homologue) plays such a role. Increasing or decreasing Hsk1-Dfp1 levels correspondingly increases or decreases origin efficiency. Furthermore, tethering Hsk1-Dfp1 near an origin increases the efficiency of that origin, suggesting that the effective local concentration of Hsk1-Dfp1 regulates origin firing. Using photobleaching, we show that Hsk1-Dfp1 is freely diffusible in the nucleus. These results support a model in which the accessibility of replication origins to Hsk1-Dfp1 regulates origin efficiency and provides a potential mechanistic link between chromatin structure and replication timing. By manipulating Hsk1-Dfp1 levels, we show that increasing or decreasing origin firing rates leads to an increase in genomic instability, demonstrating the biological importance of appropriate origin efficiency. PMID:18799612

  10. A Replication by Any Other Name: A Systematic Review of Replicative Intervention Studies

    Science.gov (United States)

    Cook, Bryan G.; Collins, Lauren W.; Cook, Sara C.; Cook, Lysandra

    2016-01-01

    Replication research is essential to scientific knowledge. Reviews of replication studies often electronically search for "replicat*" as a textword, which does not identify studies that replicate previous research but do not self-identify as such. We examined whether the 83 intervention studies published in six non-categorical research…

  11. Recommendations for Replication Research in Special Education: A Framework of Systematic, Conceptual Replications

    Science.gov (United States)

    Coyne, Michael D.; Cook, Bryan G.; Therrien, William J.

    2016-01-01

    Special education researchers conduct studies that can be considered replications. However, they do not often refer to them as replication studies. The purpose of this article is to consider the potential benefits of conceptualizing special education intervention research within a framework of systematic, conceptual replication. Specifically, we…

  12. Taxonomic study of entomopathogenic nematodes (Nematoda ...

    African Journals Online (AJOL)

    Le séquençage et l'analyse phylogénétique de la région interspécifique de l'ADN ribosomal ont groupé nos isolats avec H. sonorensis et H. Taysearae dans les arbres de parcimonie maximale et de Neighbour Joining avec les supports respectifs 94 et 99 %. Les caractères morphologiques des juvéniles infectieux et des ...

  13. Surface Microstructure Replication in Injection Moulding

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard; Arlø, Uffe Rolf

    2005-01-01

    topography is transcribed onto the plastic part through complex mechanisms. This replication however, is not perfect, and the replication quality depends on the plastic material properties, the topography itself, and the process conditions. This paper describes and discusses an investigation of injection...... moulding of surface microstructures. Emphasis is put on the ability to replicate surface microstructures under normal injection moulding conditions, notably with low cost materials at low mould temperatures. The replication of surface microstructures in injection moulding has been explored...... for Polypropylene at low mould temperatures. The process conditions were varied over the recommended process window for the material. The geometry of the obtained structures was analyzed. Evidence suggests that step height replication quality depends linearly on structure width in a certain range. Further...

  14. Surface microstructure replication in injection molding

    DEFF Research Database (Denmark)

    Theilade, Uffe Arlø; Hansen, Hans Nørgaard

    2006-01-01

    topography is transcribed onto the plastic part through complex mechanisms. This replication, however, is not perfect, and the replication quality depends on the plastic material properties, the topography itself, and the process conditions. This paper describes and discusses an investigation of injection...... molding of surface microstructures. The fundamental problem of surface microstructure replication has been studied. The research is based on specific microstructures as found in lab-on-a-chip products and on rough surfaces generated from EDM (electro discharge machining) mold cavities. Emphasis is put...... on the ability to replicate surface microstructures under normal injection-molding conditions, i.e., with commodity materials within typical process windows. It was found that within typical process windows the replication quality depends significantly on several process parameters, and especially the mold...

  15. Rescue from replication stress during mitosis.

    Science.gov (United States)

    Fragkos, Michalis; Naim, Valeria

    2017-04-03

    Genomic instability is a hallmark of cancer and a common feature of human disorders, characterized by growth defects, neurodegeneration, cancer predisposition, and aging. Recent evidence has shown that DNA replication stress is a major driver of genomic instability and tumorigenesis. Cells can undergo mitosis with under-replicated DNA or unresolved DNA structures, and specific pathways are dedicated to resolving these structures during mitosis, suggesting that mitotic rescue from replication stress (MRRS) is a key process influencing genome stability and cellular homeostasis. Deregulation of MRRS following oncogene activation or loss-of-function of caretaker genes may be the cause of chromosomal aberrations that promote cancer initiation and progression. In this review, we discuss the causes and consequences of replication stress, focusing on its persistence in mitosis as well as the mechanisms and factors involved in its resolution, and the potential impact of incomplete replication or aberrant MRRS on tumorigenesis, aging and disease.

  16. Suppression of Poxvirus Replication by Resveratrol.

    Science.gov (United States)

    Cao, Shuai; Realegeno, Susan; Pant, Anil; Satheshkumar, Panayampalli S; Yang, Zhilong

    2017-01-01

    Poxviruses continue to cause serious diseases even after eradication of the historically deadly infectious human disease, smallpox. Poxviruses are currently being developed as vaccine vectors and cancer therapeutic agents. Resveratrol is a natural polyphenol stilbenoid found in plants that has been shown to inhibit or enhance replication of a number of viruses, but the effect of resveratrol on poxvirus replication is unknown. In the present study, we found that resveratrol dramatically suppressed the replication of vaccinia virus (VACV), the prototypic member of poxviruses, in various cell types. Resveratrol also significantly reduced the replication of monkeypox virus, a zoonotic virus that is endemic in Western and Central Africa and causes human mortality. The inhibitory effect of resveratrol on poxviruses is independent of VACV N1 protein, a potential resveratrol binding target. Further experiments demonstrated that resveratrol had little effect on VACV early gene expression, while it suppressed VACV DNA synthesis, and subsequently post-replicative gene expression.

  17. Suppression of Poxvirus Replication by Resveratrol

    Directory of Open Access Journals (Sweden)

    Shuai Cao

    2017-11-01

    Full Text Available Poxviruses continue to cause serious diseases even after eradication of the historically deadly infectious human disease, smallpox. Poxviruses are currently being developed as vaccine vectors and cancer therapeutic agents. Resveratrol is a natural polyphenol stilbenoid found in plants that has been shown to inhibit or enhance replication of a number of viruses, but the effect of resveratrol on poxvirus replication is unknown. In the present study, we found that resveratrol dramatically suppressed the replication of vaccinia virus (VACV, the prototypic member of poxviruses, in various cell types. Resveratrol also significantly reduced the replication of monkeypox virus, a zoonotic virus that is endemic in Western and Central Africa and causes human mortality. The inhibitory effect of resveratrol on poxviruses is independent of VACV N1 protein, a potential resveratrol binding target. Further experiments demonstrated that resveratrol had little effect on VACV early gene expression, while it suppressed VACV DNA synthesis, and subsequently post-replicative gene expression.

  18. Adaptive radiation within marine anisakid nematodes: a zoogeographical modeling of cosmopolitan, zoonotic parasites.

    Directory of Open Access Journals (Sweden)

    Thomas Kuhn

    Full Text Available Parasites of the nematode genus Anisakis are associated with aquatic organisms. They can be found in a variety of marine hosts including whales, crustaceans, fish and cephalopods and are known to be the cause of the zoonotic disease anisakiasis, a painful inflammation of the gastro-intestinal tract caused by the accidental consumptions of infectious larvae raw or semi-raw fishery products. Since the demand on fish as dietary protein source and the export rates of seafood products in general is rapidly increasing worldwide, the knowledge about the distribution of potential foodborne human pathogens in seafood is of major significance for human health. Studies have provided evidence that a few Anisakis species can cause clinical symptoms in humans. The aim of our study was to interpolate the species range for every described Anisakis species on the basis of the existing occurrence data. We used sequence data of 373 Anisakis larvae from 30 different hosts worldwide and previously published molecular data (n = 584 from 53 field-specific publications to model the species range of Anisakis spp., using a interpolation method that combines aspects of the alpha hull interpolation algorithm as well as the conditional interpolation approach. The results of our approach strongly indicate the existence of species-specific distribution patterns of Anisakis spp. within different climate zones and oceans that are in principle congruent with those of their respective final hosts. Our results support preceding studies that propose anisakid nematodes as useful biological indicators for their final host distribution and abundance as they closely follow the trophic relationships among their successive hosts. The modeling might although be helpful for predicting the likelihood of infection in order to reduce the risk of anisakiasis cases in a given area.

  19. Penetration and post-infection development of root-knot nematodes in watermelon

    Energy Technology Data Exchange (ETDEWEB)

    López-Gómez, M.; Verdejo-Lucas, S.

    2017-07-01

    Meloidogyne javanica has showed less reproductive success than M. incognita in watermelon genotypes. This study was conducted to elucidate the low reproduction of M. javanica in watermelon. The post-infection development of M. javanica in watermelon ‘Sugar Baby’ was determined at progressively higher initial population (Pi) levels at two time points during the life cycle. Plants were inoculated with 0, 25, 50, 100, 200, and 300 second-stage juveniles (J2)/plant. The increase in Pi was correlated with the penetration rates (R2= 0.603, p<0.001) and total numbers of nematodes in the root (R2 =0.963, p< 0.001) but there was no correlation between the Pi and the reproduction factor (eggs/plant/Pi). The population in the roots at 26 days post-inoculation (dpi) consisted primarily of third-stage juveniles (J3) with a small presence of J2 and fourth stages, and egg-laying females. The dominance of the J3, when egg-laying females are expected, point to the malfunction of the feeding sites that failed to support nematode development beyond the J3 stage. The similarities in egg-laying females at 26 and 60 dpi imply the disruption of the life cycle. Watermelon compensated for M. javanica parasitism by increasing vine length (19% to 33%) and dry top weight (40%) in comparison with the non-inoculated plants. The area under the vine length progress curve was significantly larger as the Pi progressively increased (R²=0.417, p<0.001). Physiological variation was detected between the M. incognita populations. M. arenaria had less ability to invade watermelon roots than did M. incognita and M. javanica.

  20. Induction of traps by Ostertagia ostertagi larvae, chlamydospore production and growth rate in the nematode-trapping fungus Duddingtonia flagrans

    DEFF Research Database (Denmark)

    Grønvold, J.; Nansen, P.; Henriksen, S. A.

    1996-01-01

    Biological control of parasitic nematodes of domestic animals can be achieved by feeding host animals chlamydospores of the nematode-trapping fungus Duddingtonia flagrans. In the host faeces, D. flagrans develop traps that may catch nematode larvae. In experiments on agar, D. flagrans had a growth...

  1. Integrating quantitative morphological and qualitative molecular methods to analyse soil nematode community responses to plant range expansion

    NARCIS (Netherlands)

    Geisen, S.; Snoek, B.; Ten Hooven, F.C.; Duyts, H.; Kostenko, O.; Bloem, Janneke; Martens, H.J.; Quist, C.W.; Helder, Johannes; van der Putten, W.H.

    2018-01-01

    Below‐ground nematodes are important for soil functioning, as they are ubiquitous and operate at various trophic levels in the soil food web. However, morphological nematode community analysis is time consuming and requires ample training. qPCR‐based nematode identification techniques are well

  2. Molecular contest between potato and the potato cyst nematode Globodera pallida: modulation of Gpa2-mediated resistance

    NARCIS (Netherlands)

    Koropacka, K.B.

    2010-01-01

    Gpa2 recognition specificity
    Among all the multicellular animals, nematodes are the most numerous. In soil, a high variety
    of free living nematodes feeding on bacteria can be found as well as species that parasitize
    insects, animals or plants. The potato cyst nematode (PCN)

  3. Two simple methods for the collection of individual life stages of reniform nematode, Rotylenchulus reniformis

    Science.gov (United States)

    The sedentary semi-endoparasitic nematode Rotylenchulus reniformis, the reniform nematode, is a serious pest of cotton and soybean in the United States. In recent years, interest in the molecular biology of the interaction between R. reniformis and its plant hosts has increased; however, the unusual...

  4. Latitudinal variation in nematode diversity and ecological roles along the Chinese coast.

    Science.gov (United States)

    Wu, Jihua; Chen, Huili; Zhang, Youzheng

    2016-11-01

    To test changes in the phylogenetic relatedness, niche breadth, and life-history strategies of nematodes along a latitudinal gradient. Sixteen wetland locations along the Pacific coast of China, from 20°N to 40°N. Linear regression was used to relate nematode phylogenetic relatedness (average taxonomic distinctness (AvTD) and average phylogenetic diversity [AvPD]), life-history group (based on " c - p " colonizer-persister group classification), and dietary specificity (based on guild classification of feeding selectivity) to latitude. Wetland nematode taxonomic diversity (richness and Shannon diversity indices) decreased with increasing latitude along the Chinese coast. Phylogenetic diversity indices (AvTD and AvPD) significantly increased with increasing latitude. This indicates that at lower latitudes, species within the nematode community were more closely related. With increasing latitude, the nematode relative richness and abundance decreased for selective deposit feeders but increased for nonselective deposit feeders. The proportion of general opportunists decreased with increasing latitude, but persisters showed the opposite trend. The annual temperature range and the pH of sediments were more important than vegetation type in structuring nematode communities. Nematode niche breadth was narrower at lower latitudes with respect to dietary specificity. Higher latitudes with a more variable climate favor r over K life-history strategists. Nematode communities at lower latitudes contained more closely related species.

  5. Genome sequence of the metazoan plant-parasitic nematode Meloidogyne incognita

    NARCIS (Netherlands)

    Abad, P.; Gouzy, J.; Aury, J.M.; Tytgat, T.O.G.; Smant, G.

    2008-01-01

    Plant-parasitic nematodes are major agricultural pests worldwide and novel approaches to control them are sorely needed. We report the draft genome sequence of the root-knot nematode Meloidogyne incognita, a biotrophic parasite of many crops, including tomato, cotton and coffee. Most of the

  6. Optimization of a host diet for in vivo production of entomopathogenic nematodes

    Science.gov (United States)

    In previous studies, we developed an improved diet for Tenebrio molitor, a host that is used for in vivo nematode production, and we demonstrated that single insect diet components (e.g., lipids and proteins) can have a positive or negative impact on entomopathogenic nematode fitness and quality. I...

  7. Soil nematodes show a mid-elevation diversity maximum and elevational zonation on Mt. Norikura, Japan.

    Science.gov (United States)

    Dong, Ke; Moroenyane, Itumeleng; Tripathi, Binu; Kerfahi, Dorsaf; Takahashi, Koichi; Yamamoto, Naomichi; An, Choa; Cho, Hyunjun; Adams, Jonathan

    2017-06-08

    Little is known about how nematode ecology differs across elevational gradients. We investigated the soil nematode community along a ~2,200 m elevational range on Mt. Norikura, Japan, by sequencing the 18S rRNA gene. As with many other groups of organisms, nematode diversity showed a high correlation with elevation, and a maximum in mid-elevations. While elevation itself, in the context of the mid domain effect, could predict the observed unimodal pattern of soil nematode communities along the elevational gradient, mean annual temperature and soil total nitrogen concentration were the best predictors of diversity. We also found nematode community composition showed strong elevational zonation, indicating that a high degree of ecological specialization that may exist in nematodes in relation to elevation-related environmental gradients and certain nematode OTUs had ranges extending across all elevations, and these generalized OTUs made up a greater proportion of the community at high elevations - such that high elevation nematode OTUs had broader elevational ranges on average, providing an example consistent to Rapoport's elevational hypothesis. This study reveals the potential for using sequencing methods to investigate elevational gradients of small soil organisms, providing a method for rapid investigation of patterns without specialized knowledge in taxonomic identification.

  8. Azadirachtin powder for control of root-knot nematodes in tomato

    Science.gov (United States)

    USDA ARS Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center, 64 Nowelo St., Hilo, HI 96720. Root-knot nematodes cause root galling and yield reductions in many vegetable crops, including tomato. Three organic treatments to improve root growth and reduce nematode infestation were eval...

  9. The life cycle of the free-living marine nematode Innocuonema tentabunda De Man 1890

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, R.; Ingole, B.S.; Nanajkar, M.R.

    The free-living marine nematode Innocuonema tentabunda was collected from the mangrove sediment of a mud-flat at Chorao Island, Goa, India, and reared in the laboratory to investigate its life cycle at 27 plus or minus 2 degrees C. The nematodes...

  10. Genomic characterisation of the effector complement of the potato cyst nematode Globodera pallida

    NARCIS (Netherlands)

    Thorpe, P.; Mantelin, S.; Cock, P.J.A.; Blok, V.C.; Coke, M.C.; Evers-van den Akker, S.; Guzeeva, E.; Lilley, C.J.; Smant, G.; Reid, A.J.; Wright, K.M.; Urwin, P.E.; Jones, J.T.

    2014-01-01

    Background The potato cyst nematode Globodera pallida has biotrophic interactions with its host. The nematode induces a feeding structure – the syncytium – which it keeps alive for the duration of the life cycle and on which it depends for all nutrients required to develop to the adult stage.

  11. Dissecting host plant manipulation by cyst and root-knot nematodes

    NARCIS (Netherlands)

    Karczmarek, A.

    2006-01-01

    Cyst ( Globodera spp. and Heterodera spp.) and root-knot nematodes ( Meloidogyne spp.), one of the most damaging crop pests, are a perfect example of highly adapted, sophisticated root parasites. These nematodes induces specialized feeding structures (cyst

  12. First report of the root-knot nematode Meloidogyne ethiopica on tomato in Slovenia

    NARCIS (Netherlands)

    Sirca, S.; Urek, G.; Karssen, G.

    2004-01-01

    The root-knot nematode Meloidogyne ethiopica Whitehead originally described from Tanzania is also distributed in South Africa, Zimbabwe, and Ethiopia (3). Although this species is a relatively unknown root-knot nematode, M. ethiopica parasitizes several economical important crops, such as tomato,

  13. The plant-parasitic nematode collections of RRIP: The realization of an ISTC project

    Science.gov (United States)

    Plant-parasitic nematodes are important pests of agricultural and wild plants throughout Russia and the world. The best strategy for management of nematode damage is an integrated approach to the problem: i.e., the use of agrotechnological approaches (crop rotation, soil amendments, etc.), reasonabl...

  14. Distribution and infestation rate of cyst nematodes (Tylenchida: Heteroderidae) in cabbage growing areas in Samsun

    Science.gov (United States)

    Information concerning the occurrence and distribution of cyst nematodes (Heterodera spp.) in Samsun, Turkey is needed to assess their potential to cause economic damage on many crop plants. Surveys on the distribution and infestation rates of cyst nematodes in cabbage fields in Samsun were conducte...

  15. Assessment of the effects of Hirsutella minnesotensis on Soybean Cyst Nematode and growth of soybean

    Science.gov (United States)

    Hirsutella minnesotensis is a fungal endoparasite of nematodes juvenile and parasitizes soybean cyst nematodes (SCN) with high frequency. In this study, the effects of two H. minnesotensis isolates on population and distribution of SCN and growth of soybean were evaluated. Experiments were conducted...

  16. Diversity and incidence of plant-parasitic nematodes in Belgian turf grass

    NARCIS (Netherlands)

    Vandenbossche, B.; Viaene, N.; Sutter, de N.; Maes, M.; Karssen, G.; Bert, W.

    2011-01-01

    Eleven golf courses and eight football pitches, located in Belgium, were surveyed for plant-parasitic nematodes. This revealed a remarkably high diversity: 52 different species/taxa were identified morphologically, belonging to 23 genera and nine families. Among the most prevalent nematodes on both

  17. Population Genetics of Hirsutella rhossiliensis, a Dominant Parasite of Cyst Nematode Juveniles on a Continental Scale.

    Science.gov (United States)

    Wang, Niuniu; Zhang, Yongjie; Jiang, Xianzhi; Shu, Chi; Hamid, M Imran; Hussain, Muzammil; Chen, Senyu; Xu, Jianping; Xiang, Meichun; Liu, Xingzhong

    2016-11-01

    Hirsutella rhossiliensis is a parasite of juvenile nematodes, effective against a diversity of plant-parasitic nematodes. Its global distribution on various nematode hosts and its genetic variation for several geographic regions have been reported, while the global population genetic structure and factors underlying patterns of genetic variation of H. rhossiliensis are unclear. In this study, 87 H. rhossiliensis strains from five nematode species (Globodera sp., Criconemella xenoplax, Rotylenchus robustus, Heterodera schachtii, and Heterodera glycines) in Europe, the United States, and China were investigated by multilocus sequence analyses. A total of 280 variable sites (frequency, 0.6%) at eight loci and six clustering in high accordance with geographic populations or host nematode-associated populations were identified. Although H. rhossiliensis is currently recognized as an asexual fungus, recombination events were frequently detected. In addition, significant genetic isolation by geography and nematode hosts was revealed. Overall, our analyses showed that recombination, geographic isolation, and nematode host adaptation have played significant roles in the evolutionary history of H. rhossiliensis IMPORTANCE: H. rhossiliensis has great potential for use as a biocontrol agent to control nematodes in a sustainable manner as an endoparasitic fungus. Therefore, this study has important implications for the use of H. rhossiliensis as a biocontrol agent and provides interesting insights into the biology of this species. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  18. RNA Interference: A Novel Source of Resistance to Combat Plant Parasitic Nematodes

    Directory of Open Access Journals (Sweden)

    Sagar Banerjee

    2017-05-01

    Full Text Available Plant parasitic nematodes cause severe damage and yield loss in major crops all over the world. Available control strategies include use of insecticides/nematicides but these have proved detrimental to the environment, while other strategies like crop rotation and resistant cultivars have serious limitations. This scenario provides an opportunity for the utilization of technological advances like RNA interference (RNAi to engineer resistance against these devastating parasites. First demonstrated in the model free living nematode, Caenorhabtidis elegans; the phenomenon of RNAi has been successfully used to suppress essential genes of plant parasitic nematodes involved in parasitism, nematode development and mRNA metabolism. Synthetic neurotransmitants mixed with dsRNA solutions are used for in vitro RNAi in plant parasitic nematodes with significant success. However, host delivered in planta RNAi has proved to be a pioneering phenomenon to deliver dsRNAs to feeding nematodes and silence the target genes to achieve resistance. Highly enriched genomic databases are exploited to limit off target effects and ensure sequence specific silencing. Technological advances like gene stacking and use of nematode inducible and tissue specific promoters can further enhance the utility of RNAi based transgenics against plant parasitic nematodes.

  19. Toxicity of 2,4-diacetylphloroglucinol (DAPG) to plant-parasitic and bacterial-feeding nematodes.

    Science.gov (United States)

    Meyer, Susan L F; Halbrendt, John M; Carta, Lynn K; Skantar, Andrea M; Liu, Ting; Abdelnabby, Hazem M E; Vinyard, Bryan T

    2009-12-01

    The antibiotic 2,4-diacetylphloroglucinol (DAPG) is produced by some isolates of the beneficial bacterium Pseudomonas fluorescens. DAPG is toxic to many organisms, and crop yield increases have been reported after application of DAPG-producing P. fluorescens. This study was conducted to determine whether DAPG is toxic to selected nematodes. The plant-parasitic nematodes Heterodera glycines, Meloidogyne incognita, Pratylenchus scribneri and Xiphinema americanum, and the bacterial-feeding nematodes Caenorhabditis elegans, Pristionchus pacificus, and Rhabditis rainai, were immersed in concentrations ranging from 0 to 100 μg/ml DAPG. Egg hatch and viability of juveniles and adults were determined. DAPG was toxic to X. americanum adults, with an LD₅₀ of 8.3 μg/ml DAPG. DAPG decreased M. incognita egg hatch, but stimulated C. elegans hatch during the first hours of incubation. Viability of M. incognita J2 and of C. elegans J1 and adults was not affected. There were no observed effects on the other nematodes. The study indicated that DAPG is not toxic to all nematodes, and did not affect the tested species of beneficial bacterial-feeding nematodes. Augmentation of DAPG-producing P. fluorescens populations for nematode biocontrol could be targeted to specific nematode species known to be affected by this compound and by other antibiotics produced by the bacteria, or these bacteria could be used for other possible effects, such as induced plant resistance.

  20. Controlling Aphelenchoides subtenuis nematodes with a hot water treatment in Crocus and Allium

    NARCIS (Netherlands)

    Leeuwen, van P.J.; Trompert, J.P.T.

    2011-01-01

    Several bulbous crops like Crocus, Allium and some species of Tulipa and Narcissus can be infected with the nematode Aphelenchoides subtenuis. The nematodes cause retarded growth, poor or no flowering and eventually death of the bulbs and corms. A hot water treatment after lifting the bulbs has

  1. Nematodes as sentinels of heavy metals and organic toxicants in the soil

    NARCIS (Netherlands)

    Ekschmitt, K.; Korthals, G.W.

    2006-01-01

    Field and laboratory research has repeatedly shown that free-living soil nematodes differ in their sensitivity to soil pollution. In this paper, we analyze whether nematode genera proved sensitive or tolerant toward heavy metals and organic pollutants in six long-term field experiments. We discuss

  2. Low cost production of nematodes for biological control of insect pests

    Science.gov (United States)

    Entomopathogenic nematodes are produced in two ways: in artificial media using liquid or solid fermentation methods (in vitro) or by mass producing insect hosts to be artificially exposed to mass infection by nematodes (in vivo). The yellow mealworm (Tenebrio molitor) is a good host for in vivo nema...

  3. Development of a desiccated cadaver delivery system to apply entomopathogenic nematodes for control of soil pests

    Science.gov (United States)

    Pentomopathogenic nematodes may be more capable of controlling soil pests when they are harbored by desiccated cadavers. A small-scale system was developed from a modified crop seed planter to effectively deliver desiccated nematode-infected cadavers into the soil. The system mainly consists of a me...

  4. Tracing organic matter sources of estuarine tidal flat nematodes with stable carbon isotopes

    NARCIS (Netherlands)

    Moens, T.; Luyten, C.; Middelburg, J.J.; Herman, P.M.J.; Vincx, M.

    2002-01-01

    The present study explores the use of stable carbon isotopes to trace organic matter sources of intertidal nematodes in the Schelde estuary (SW Netherlands). Stable carbon isotope signatures of nematodes from a saltmarsh and 4 tidal flat stations were determined in spring and winter situations, and

  5. In vivo effects of Sainfoin (Onobrychis viciifolia) on parasitic nematodes in calves

    DEFF Research Database (Denmark)

    Desrues, Oliver; Pena-Espinoza, Miguel Angel; Hansen, T.V.A.

    Sainfoin (Onobrychis viciifolia) is a fodder legume containing condensed tannins known to improve protein self-sufficiency, animal health and environment. In addition, anthelmintic effects have been demonstrated in vitro against cattle nematodes, and in vivo against nematodes of small ruminants...

  6. Evaluation of tomato genotypes for resistance to root-knot nematodes

    African Journals Online (AJOL)

    Tomato (Solanum lycopersicum) is one of the most popular vegetable crops worldwide, owing to its high nutritive value and diversified use. Tomato production in Ghana is threatened by plant parasitic nematodes, especially the root knot nematodes (Meloidogyne spp.), which are responsible for huge economic yield losses.

  7. Controlling tulip stem nematodes in tulip bulbs by a hot water treatment

    NARCIS (Netherlands)

    Dam, van M.F.N.

    2013-01-01

    A hot water treatment (HWT) protocol is needed to control tulip stem nematode (TSN) in tulip bulbs. A HWT above approximately 45°C in tulips is assumed to be harmful to the bulbs. Experience with HWT to destroy stem nematodes in daffodils shows that the required temperature for this is 4 hours at

  8. Data from Investigating Variation in Replicability: A “Many Labs” Replication Project

    Directory of Open Access Journals (Sweden)

    Richard A. Klein

    2014-04-01

    Full Text Available This dataset is from the Many Labs Replication Project in which 13 effects were replicated across 36 samples and over 6,000 participants. Data from the replications are included, along with demographic variables about the participants and contextual information about the environment in which the replication was conducted. Data were collected in-lab and online through a standardized procedure administered via an online link. The dataset is stored on the Open Science Framework website. These data could be used to further investigate the results of the included 13 effects or to study replication and generalizability more broadly.

  9. Mercury in parasitic nematodes and trematodes and their double-crested cormorant hosts: Bioaccumulation in the face of sequestration by nematodes

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Stacey A., E-mail: srobinsc@connect.carleton.ca [Department of Biology, Carleton University, 209 Nesbitt Bldg, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6 (Canada); Forbes, Mark R., E-mail: mforbes6@gmail.com [Department of Biology, Carleton University, 209 Nesbitt Bldg, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6 (Canada); Hebert, Craig E., E-mail: Craig.Hebert@ec.gc.ca [Environment Canada, National Wildlife Research Centre, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1A 0H3 (Canada)

    2010-10-15

    Endoparasites can alter their host's heavy metal concentrations by sequestering metals in their own tissues. Contracaecum spp. (a nematode), but not Drepanocephalus spathans (a trematode), were bioaccumulating mercury to concentrations 1.5 times above cormorant hosts. Nematodes did not have significantly greater stable nitrogen isotope values ({delta}{sup 15}N) than their hosts, which is contradictory to prey-predator trophic enrichment studies, but is in agreement with other endoparasite-host relationships. However, Contracaecum spp. {delta}{sup 13}C values were significantly greater than their hosts, which suggest that nematodes were consuming host tissues. Nematodes were accumulating and thus sequestering some of their cormorant hosts' body burden of methyl mercury; however, they were not dramatically reducing their hosts' accumulation of methyl mercury.

  10. Mercury in parasitic nematodes and trematodes and their double-crested cormorant hosts: Bioaccumulation in the face of sequestration by nematodes

    International Nuclear Information System (INIS)

    Robinson, Stacey A.; Forbes, Mark R.; Hebert, Craig E.

    2010-01-01

    Endoparasites can alter their host's heavy metal concentrations by sequestering metals in their own tissues. Contracaecum spp. (a nematode), but not Drepanocephalus spathans (a trematode), were bioaccumulating mercury to concentrations 1.5 times above cormorant hosts. Nematodes did not have significantly greater stable nitrogen isotope values (δ 15 N) than their hosts, which is contradictory to prey-predator trophic enrichment studies, but is in agreement with other endoparasite-host relationships. However, Contracaecum spp. δ 13 C values were significantly greater than their hosts, which suggest that nematodes were consuming host tissues. Nematodes were accumulating and thus sequestering some of their cormorant hosts' body burden of methyl mercury; however, they were not dramatically reducing their hosts' accumulation of methyl mercury.

  11. Targeting DNA Replication Stress for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2016-08-01

    Full Text Available The human cellular genome is under constant stress from extrinsic and intrinsic factors, which can lead to DNA damage and defective replication. In normal cells, DNA damage response (DDR mediated by various checkpoints will either activate the DNA repair system or induce cellular apoptosis/senescence, therefore maintaining overall genomic integrity. Cancer cells, however, due to constitutive growth signaling and defective DDR, may exhibit “replication stress” —a phenomenon unique to cancer cells that is described as the perturbation of error-free DNA replication and slow-down of DNA synthesis. Although replication stress has been proven to induce genomic instability and tumorigenesis, recent studies have counterintuitively shown that enhancing replicative stress through further loosening of the remaining checkpoints in cancer cells to induce their catastrophic failure of proliferation may provide an alternative therapeutic approach. In this review, we discuss the rationale to enhance replicative stress in cancer cells, past approaches using traditional radiation and chemotherapy, and emerging approaches targeting the signaling cascades induced by DNA damage. We also summarize current clinical trials exploring these strategies and propose future research directions including the use of combination therapies, and the identification of potential new targets and biomarkers to track and predict treatment responses to targeting DNA replication stress.

  12. Factors influencing microinjection molding replication quality

    Science.gov (United States)

    Vera, Julie; Brulez, Anne-Catherine; Contraires, Elise; Larochette, Mathieu; Trannoy-Orban, Nathalie; Pignon, Maxime; Mauclair, Cyril; Valette, Stéphane; Benayoun, Stéphane

    2018-01-01

    In recent years, there has been increased interest in producing and providing high-precision plastic parts that can be manufactured by microinjection molding: gears, pumps, optical grating elements, and so on. For all of these applications, the replication quality is essential. This study has two goals: (1) fabrication of high-precision parts using the conventional injection molding machine; (2) identification of robust parameters that ensure production quality. Thus, different technological solutions have been used: cavity vacuuming and the use of a mold coated with DLC or CrN deposits. AFM and SEM analyses were carried out to characterize the replication profile. The replication quality was studied in terms of the process parameters, coated and uncoated molds and crystallinity of the polymer. Specific studies were processed to quantify the replicability of injection molded parts (ABS, PC and PP). Analysis of the Taguchi experimental designs permits prioritization of the impact of each parameter on the replication quality. A discussion taking into account these new parameters and the thermal and spreading properties on the coatings is proposed. It appeared that, in general, increasing the mold temperature improves the molten polymer fill in submicron features except for the steel insert (for which the presence of a vacuum is the most important factor). Moreover, the DLC coating was the best coating to increase the quality of the replication. This result could be explained by the lower thermal diffusivity of this coating. We noted that the viscosity of the polymers is not a primordial factor of the replication quality.

  13. The Inherent Asymmetry of DNA Replication.

    Science.gov (United States)

    Snedeker, Jonathan; Wooten, Matthew; Chen, Xin

    2017-10-06

    Semiconservative DNA replication has provided an elegant solution to the fundamental problem of how life is able to proliferate in a way that allows cells, organisms, and populations to survive and replicate many times over. Somewhat lost, however, in our admiration for this mechanism is an appreciation for the asymmetries that occur in the process of DNA replication. As we discuss in this review, these asymmetries arise as a consequence of the structure of the DNA molecule and the enzymatic mechanism of DNA synthesis. Increasing evidence suggests that asymmetries in DNA replication are able to play a central role in the processes of adaptation and evolution by shaping the mutagenic landscape of cells. Additionally, in eukaryotes, recent work has demonstrated that the inherent asymmetries in DNA replication may play an important role in the process of chromatin replication. As chromatin plays an essential role in defining cell identity, asymmetries generated during the process of DNA replication may play critical roles in cell fate decisions related to patterning and development.

  14. Ultrastructural Characterization of Zika Virus Replication Factories

    Directory of Open Access Journals (Sweden)

    Mirko Cortese

    2017-02-01

    Full Text Available Summary: A global concern has emerged with the pandemic spread of Zika virus (ZIKV infections that can cause severe neurological symptoms in adults and newborns. ZIKV is a positive-strand RNA virus replicating in virus-induced membranous replication factories (RFs. Here we used various imaging techniques to investigate the ultrastructural details of ZIKV RFs and their relationship with host cell organelles. Analyses of human hepatic cells and neural progenitor cells infected with ZIKV revealed endoplasmic reticulum (ER membrane invaginations containing pore-like openings toward the cytosol, reminiscent to RFs in Dengue virus-infected cells. Both the MR766 African strain and the H/PF/2013 Asian strain, the latter linked to neurological diseases, induce RFs of similar architecture. Importantly, ZIKV infection causes a drastic reorganization of microtubules and intermediate filaments forming cage-like structures surrounding the viral RF. Consistently, ZIKV replication is suppressed by cytoskeleton-targeting drugs. Thus, ZIKV RFs are tightly linked to rearrangements of the host cell cytoskeleton. : Cortese et al. show that ZIKV infection in both human hepatoma and neuronal progenitor cells induces drastic structural modification of the cellular architecture. Microtubules and intermediate filaments surround the viral replication factory composed of vesicles corresponding to ER membrane invagination toward the ER lumen. Importantly, alteration of microtubule flexibility impairs ZIKV replication. Keywords: Zika virus, flavivirus, human neural progenitor cells, replication factories, replication organelles, microtubules, intermediate filaments, electron microscopy, electron tomography, live-cell imaging

  15. THE PREVALENCE OF GASTROINTESTINAL NEMATODES OF BALI CATTLE BREEDERS IN NUSA PENIDA

    Directory of Open Access Journals (Sweden)

    Putu Agus Trisna Kusuma Antara

    2017-08-01

    Full Text Available Nusa Penida is a pure breeding area of bali cattle, in which the cattle are mainly kept in conventional maintenance system and potentially infected by parasite, especially gastrointestinal nematodes. This study aims were to determine the prevalence and type of gastrointestinal nematodes in bali cattle breeders in Nusa Penida. Fecal samples were taken from 50 bali cattle breeders kept in cages (simantri and another 50 samples were from cattle not kept in cage. The floating method was used for morphological examination and prevalence, the data was analyzed with descriptive analysis. The results showed, the prevalence of bovine gastrointestinal nematodes in Nusa Penida was 25%. The prevalence of nematode infection in bali cattle that kept cages was lower compared to the cattle that were not kept in cage. Strongyloides papillosus and Capillaria bovis were the gastrointestinal nematodes found in the infected cattle.

  16. Connection between the decline of spruce and occurrence of animal pests, especially nematodes

    Energy Technology Data Exchange (ETDEWEB)

    Timans, U.

    1986-12-01

    In various regions of Bavaria, affected by the decline of spruce, attack by insects and especially nematodes was examined on diseased and healthy spruces. A connection between harmful forest insects and the decline of spruce did not become evident, neither over wide areas nor by examination of single trees. Attack by nematodes was examined in soil and wood samples and also in fine feeder roots of diseased and healthy trees. Plant-parasitic nematodes were not found in the wood and in feeder roots. Although root-parasitic nematodes were present in soil samples, their density was too little to account for a direct damage to spruce. They occurred likewise in samples from healthy and diseased trees. Plant-parasitic nematodes can thus be excluded as a possible causal agent for the decline of spruce.

  17. Infestation of natural populations of earthworm cocoons by rhabditid and cephalobid nematodes

    DEFF Research Database (Denmark)

    Kraglund, HO; Ekelund, Flemming

    2002-01-01

    Nematodes infested 13 of 100 earthworm cocoons from a compost pile and 17 of 197 cocoons from a permanent pasture soil. Between one and 2000 nematodes were found within the infested cocoons. All nematodes found in cocoons from the compost pile belonged to the genus Rhabditis, while Rhabditis spp....... as well as members of Cephalobidae infested earthworm cocoons in the pasture soil. In cultures established from cocoons found in the pasture soil, at least five different types of nematodes belonging to the family Cephalobidae were found. Acrobeloides nanus was found in six cocoons, Cephalobus persegnis...... was found in four and Chiloplacus minimus was found in one cocoon. We suggest that earthworm - nematode interactions may be an important pathway for the transfer of carbon in terrestrial ecosystems, and that the inclusion of these pathways may lead to a better understanding of soil food web functioning....

  18. 'David and Goliath' of the soil food web - Flagellates that kill nematodes

    DEFF Research Database (Denmark)

    Strandmark, Lisa Bjørnlund; Rønn, Regin

    2008-01-01

    Nematodes and flagellates are important bacterial predators in soil and sediments. Generally, these organisms are considered to be competitors for bacterial food. We studied the interaction among flagellates and nematodes using axenic liquid cultures amended with heat-killed bacteria as food...... and showed for the first time that a small and common soil flagellate (Cercomonas sp.) is able to attack and kill the much larger nematode Caenorhabditis elegans. The killing process is not caused by soluble metabolites but requires direct contact between the flagellate cells and the nematode surface...... and occurs rapidly (within a few hours) at high flagellate density. At lower flagellate density, adult nematodes sometimes avoid attachment of flagellates, feed on them and become the dominant bacterial predator. Considering that bacterial feeders affect bacterial communities differently, and that one...

  19. Association between entomopathogenic nematodes and fungi for control of Rhipicephalus microplus (Acari: Ixodidae).

    Science.gov (United States)

    Monteiro, Caio Márcio Oliveira; Araújo, Laryssa Xavier; Matos, Renata Silva; da Silva Golo, Patrícia; Angelo, Isabele Costa; de Souza Perinotto, Wendell Marcelo; Coelho Rodrigues, Camila Aparecida; Furlong, John; Bittencourt, Vânia Rita Elias Pinheiro; Prata, Márcia Cristina Azevedo

    2013-10-01

    The aim of the study was to assess the effect of the association of entomopathogenic nematodes and fungi on Rhipicephalus microplus. The nematodes used were Heterorhabditis bacteriophora HP88 and Heterorhabditis indica LPP1 and the fungi were Metarhizium anisopliae IBCB 116 and Beauveria bassiana ESALQ 986. In the groups treated with the fungi, the females were immersed for 3 min in a conidial suspension, while in the groups treated with the nematodes, the ticks were exposed to infective juveniles. To evaluate the interaction between entomopathogens, the females were first immersed in a conidial suspension and then exposed to the nematodes. The egg mass weight and hatching percentage values of the groups treated with M. anisopliae IBCB 116 and B. bassiana ESALQ 986 in the two experiments were statistically similar (p > 0.05) to the values of the control group. In the groups treated only with nematodes, there was a significant reduction (p fungus M. anisopliae IBCB 116.

  20. A northward colonisation of the Andes by the potato cyst nematode during geological times suggests multiple host-shifts from wild to cultivated potatoes.

    Science.gov (United States)

    Picard, Damien; Sempere, Thierry; Plantard, Olivier

    2007-02-01

    The cyst nematode Globodera pallida is a major pest of potato in South America where this specialist parasite is native. To investigate its phylogeography, we have genotyped individuals from 42 Peruvian populations using mitochondrial and nuclear molecular markers. A clear south-to-north phylogeographical pattern was revealed with five well-supported clades. The clade containing the southern populations is genetically more diverse and forms the most basal branch. The large divergence among cytochrome b haplotypes suggests that they diverged before human domestication of potato. As the nematodes studied have been sampled on cultivated potato, multiple host-shifts from wild to cultivated potatoes must have occurred independently in each clade. We hypothesise that this south-to-north pattern took place during the uplift of the Andes beginning 20 My ago and following the same direction. To our knowledge, this is the first study of a plant parasite sampled on cultivated plants revealing an ancient phylogeographical pattern.