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Sample records for pinewood nematode bursaphelenchus

  1. Control of the pinewood nematode Bursaphelenchus xylophilus by essential oils and extracts obtained from plants: a review.

    OpenAIRE

    Barbosa, Pedro; Vieira, Paulo; Dias, LS; Pedro, LG; Barroso, JG; Figueiredo, AC; Mota, Manuel

    2012-01-01

    The pinewood nematode (PWN), Bursaphelenchus xylophilus, is a serious threat to forest ecosystems at a global scale. The nematode has become a major quarantine problem due to its capability to completely destroy Pinus spp. trees, with great damage to the wood industry. Controlling the nematode inside a living tree is quite difficult, the techniques used being often ineffective and quite expensive. In the coming years, most chemicals used to control nematodes will be banned and ...

  2. Identification and characterization of a dual-acting antinematodal agent against the pinewood nematode, Bursaphelenchus xylophilus.

    Directory of Open Access Journals (Sweden)

    Wan-Suk Oh

    Full Text Available The pinewood nematode (PWN, Bursaphelenchus xylophilus, is a mycophagous and phytophagous pathogen responsible for the current widespread epidemic of the pine wilt disease, which has become a major threat to pine forests throughout the world. Despite the availability of several preventive trunk-injection agents, no therapeutic trunk-injection agent for eradication of PWN currently exists. In the characterization of basic physiological properties of B. xylophilus YB-1 isolates, we established a high-throughput screening (HTS method that identifies potential hits within approximately 7 h. Using this HTS method, we screened 206 compounds with known activities, mostly antifungal, for antinematodal activities and identified HWY-4213 (1-n-undecyl-2-[2-fluorphenyl] methyl-3,4-dihydro-6,7-dimethoxy-isoquinolinium chloride, a highly water-soluble protoberberine derivative, as a potent nematicidal and antifungal agent. When tested on 4 year-old pinewood seedlings that were infected with YB-1 isolates, HWY-4213 exhibited a potent therapeutic nematicidal activity. Further tests of screening 39 Caenorhabditis elegans mutants deficient in channel proteins and B. xylophilus sensitivity to Ca(2+ channel blockers suggested that HWY-4213 targets the calcium channel proteins. Our study marks a technical breakthrough by developing a novel HTS method that leads to the discovery HWY-4213 as a dual-acting antinematodal and antifungal compound.

  3. Geographical variation in seasonality and life history of pine sawyer beetles Monochamus spp: its relationship with phoresy by the pinewood nematode Bursaphelenchus xylophilus.

    Science.gov (United States)

    Carla S. Pimentel; Matthew P. Ayres; Vallery Erich; Chris Young; Douglas Streett

    2014-01-01

    Bursaphelenchus xylophilus (Steiner & Buhrer) (Nematoda: Aphelenchoididae), the pinewood nematode and the causal agent of the pine wilt disease, is a globally important invasive pathogen of pine forests. It is phoretic in woodborer beetles of the genus Monochamus (Megerle) (Coleoptera, Cerambycidae) and has been able to exploit novel indigenous species of...

  4. Basic density, extractive content and moisture sorption properties of Pinus pinaster wood infected with the pinewood nematode, Bursaphelenchus xylophilus

    Institute of Scientific and Technical Information of China (English)

    Valeria Reva; Luı´s Fonseca; Jose´ L. Lousada; Isabel Abrantes; Anto´ nio R. Figueiredo; Domingos X. Viegas

    2015-01-01

    The pinewood nematode (PWN), Bursaphe-lenchus xylophilus, has become one of the most severe threats to pine forest worldwide. Nematodes, migrating through resin canals and feeding on the living cells, induce rapid metabolic changes in ray parenchyma cells, create cavitation areas, decrease xylem water content and oleo-resin exudation, and cause necrosis of parenchyma and cambial cells. This study focused on the impact of PWN infection on technological parameters of wood and evalu-ated the impact of anatomic and biochemical incidences of tree defense reactions on basic density, extractive content and moisture sorption properties of Pinus pinaster wood. Samples of infected and uninfected wood were studied. The presence of nematodes reduced wood basic density by 2% and decreased the total content of extractives in infected wood as compared with uninfected (5.98 and 8.90% of dry wood mass, respectively). Extractives in infected trees had inverse distribution along the trunk as compared with uninfected trees. The adsorption isotherms for infected and uninfected wood had similar positioning. We recorded differences (some statistically significant) in the equilibrium moisture content of infected and uninfected wood under varying environmental conditions. Despite the verified differences in wood basic density, extractive con-tent and moisture sorption properties, the overall conclu-sion is that the PWN had a slight impact on these characteristics of wood.

  5. Nematicidal activity of essential oils and volatiles derived from Portuguese aromatic flora against the pinewood nematode, Bursaphelenchus xylophilus.

    Science.gov (United States)

    Barbosa, P; Lima, A S; Vieira, P; Dias, L S; Tinoco, M T; Barroso, J G; Pedro, L G; Figueiredo, A C; Mota, M

    2010-03-01

    Twenty seven essential oils, isolated from plants representing 11 families of Portuguese flora, were screened for their nematicidal activity against the pinewood nematode (PWN), Bursaphelenchus xylophilus. The essential oils were isolated by hydrodistillation and the volatiles by distillation-extraction, and both were analysed by GC and GC-MS. High nematicidal activity was achieved with essential oils from Chamaespartium tridentatum, Origanum vulgare, Satureja montana, Thymbra capitata, and Thymus caespititius. All of these essential oils had an estimated minimum inhibitory concentration ranging between 0.097 and 0.374 mg/ml and a lethal concentration necessary to kill 100% of the population (LC(100)) between 0.858 and 1.984 mg/ml. Good nematicidal activity was also obtained with the essential oil from Cymbopogon citratus. The dominant components of the effective oils were 1-octen-3-ol (9%), n-nonanal, and linalool (both 7%) in C. tridentatum, geranial (43%), neral (29%), and β-myrcene (25%) in C. citratus, carvacrol (36% and 39%), γ-terpinene (24% and 40%), and p-cymene (14% and 7%) in O. vulgare and S. montana, respectively, and carvacrol (75% and 65%, respectively) in T. capitata and T. caespititius. The other essential oils obtained from Portuguese flora yielded weak or no activity. Five essential oils with nematicidal activity against PWN are reported for the first time.

  6. Efficacy of Four Nematicides Against the Reproduction and Development of Pinewood Nematode, Bursaphelenchus xylophilus.

    Science.gov (United States)

    Bi, Zhenzhen; Gong, Yanting; Huang, Xiaojuan; Yu, Hongshi; Bai, Liqun; Hu, Jiafu

    2015-06-01

    To understand the efficacy of emamectin benzoate, avermectin, milbemectin, and thiacloprid on the reproduction and development of Bursaphelenchus xylophilus, seven parameters, namely population growth, fecundity, egg hatchability, larval lethality, percent larval development, body size, and sexual ratio, were investigated using sublethal (LC20) doses of these compounds in the laboratory. Emamectin benzoate treatment led to a significant suppression in population size, brood size, and percent larval development with 411, 3.50, and 49.63%, respectively, compared to 20850, 24.33, and 61.43% for the negative control. The embryonic and larval lethality increased obviously from 12.47% and 13.70% to 51.37% and 75.30%, respectively. In addition, the body length was also significantly reduced for both males and females in the emamectin benzoate treatment. Avermectin and milbemectin were also effective in suppressing population growth by increasing larval lethality and reducing larval development, although they did not affect either brood size or embryonic lethality. Body length for both male and female worms was increased by avermectin. Thiacloprid caused no adverse reproductive effects, although it suppressed larval development. Sexual ratio was not affected by any of these four nematicides. Our results indicate that emamectin benzoate, milbemectin, and avermectin are effective against the reproduction of B. xylophilus. We think these three nematicides can be useful for the control of pine wilt disease.

  7. Host and vector surveys for the pinewood nematode bursaphelenchus xylophilus (steiner and buhrer) nickle (nematoda: aphelenchoididae) in canada. Information report No. N-X-285

    Energy Technology Data Exchange (ETDEWEB)

    Bowers, W.W.; Hudak, J.; Raske, A.G.; Magasi, L.P.

    1992-01-01

    The pinewood nematode is an important forest pest because it causes wilting and considerable tree mortality, particularly in Japan. It was first reported in Manitoba in 1982, although there are no cases of tree mortality in Canada. It is ranked in the first level as a potentially important pest internationally and the Scandinavian countries have restricted the importation of conifer chips and timber from countries where the pest is known to occur, a major concern of Canadian forest managers and lumber exporters. In 1985, the Forest Insect and Disease Survey began a nationwide survey to determine the distribution of the pinewood nematode. This report briefly reviews its history and biology and presents the results of the Canadian survey.

  8. Bioassays Against Pinewood Nematode: Assessment of a Suitable Dilution Agent and Screening for Bioactive Essential Oils

    OpenAIRE

    Ana Cristina Figueiredo; Luis G. Pedro; Barroso, José G.; Maria Teresa Tinoco; Luís Silva Dias; Mendes, Marta D.; Jorge M. S. Faria; Pedro Barbosa; Manuel Mota

    2012-01-01

    Acetone was investigated and found to be an appropriate alternative to Triton X-100 as a solvent of essential oils in bioassays aimed to investigate their effects on pinewood nematode (Bursaphelenchus xylophilus) mortality. Therefore it was used as dilution agent to screen the effectiveness of fifty two essential oils against this pest. Thirteen essential oils were highly effective, resulting in more than 90% pinewood nematode mortality at 2 mg/mL, with six of them resulting in 100% mortality...

  9. Mechanisms of invasive population establishment and spread of pinewood nematodes in China

    Institute of Scientific and Technical Information of China (English)

    XIE BingYan; CHENG XinYue; SHI Juan; ZHANG QingWen; DAI ShuMing; CHENG Fei Xue; LUO YouQing

    2009-01-01

    This paper summarizes the results of our study of the pinewood nematode (Bursaphelenchus xylophi-lus). By population genetic analysis, it was determined that there was no genetic bottle caused by the founder effect and genetic drift in the Chinese invasive population. Multiple invasions with large amounts of nematodes from different sources led to rich genetic diversity in the invasive population. Keeping high genetic diversity in the invasive process may be one of the genetic mechanisms in its successful invasion. By testing interspecies competition, it was shown that, with high fecundity and a strong competitive ability, B. Xylophilus outcompeted the native species B. Mucronatus in the natural ecosystem during the invasion process. Competitive displacement may be one of the ecological mechanisms of B. Xylophilus's invasion. In addition, an unequal interspecific hybridization with intro-gress was in favor of the invasive species which also accelerated the replacement of B. Mucronatus by B. Xylophilus. The structures, functions and evolutions of a few important genes that are closely related to the ecological adaptation of pinewood nematodes were studied to explore the molecular mechanism of its ecological adaptations. Further, the resistance and resilience mechanism of the pine ecosystem invaded by pinewood nematodes was also investigated. The results of these studies uncovered a por-tion of the genetic and ecological mechanisms of PWN's successful invasion and laid a foundation for further study to obtain a comprehensive interpretation of the mechanisms of the nematode invasion. The results also provided a scientific basis for effectively controlling the occurrence and spread of pine wilt disease which is caused by nematodes. Various aspects requiring further investigation are considered.

  10. Mechanisms of invasive population establishment and spread of pinewood nematodes in China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper summarizes the results of our study of the pinewood nematode(Bursaphelenchus xylophi-lus).By population genetic analysis,it was determined that there was no genetic bottle caused by the founder effect and genetic drift in the Chinese invasive population.Multiple invasions with large amounts of nematodes from different sources led to rich genetic diversity in the invasive population.Keeping high genetic diversity in the invasive process may be one of the genetic mechanisms in its successful invasion.By testing interspecies competition,it was shown that,with high fecundity and a strong competitive ability,B.xylophilus outcompeted the native species B.mucronatus in the natural ecosystem during the invasion process.Competitive displacement may be one of the ecological mechanisms of B.xylophilus’s invasion.In addition,an unequal interspecific hybridization with intro-gress was in favor of the invasive species which also accelerated the replacement of B.mucronatus by B.xylophilus.The structures,functions and evolutions of a few important genes that are closely related to the ecological adaptation of pinewood nematodes were studied to explore the molecular mechanism of its ecological adaptations.Further,the resistance and resilience mechanism of the pine ecosystem invaded by pinewood nematodes was also investigated.The results of these studies uncovered a portion of the genetic and ecological mechanisms of PWN’s successful invasion and laid a foundation for further study to obtain a comprehensive interpretation of the mechanisms of the nematode invasion.The results also provided a scientific basis for effectively controlling the occurrence and spread of pine wilt disease which is caused by nematodes.Various aspects requiring further investigation are considered.

  11. Nematicidal Activity of Plant Essential Oils and Components From Ajowan (Trachyspermum ammi), Allspice (Pimenta dioica) and Litsea (Litsea cubeba) Essential Oils Against Pine Wood Nematode (Bursaphelenchus Xylophilus).

    Science.gov (United States)

    Park, Il-Kwon; Kim, Junheon; Lee, Sang-Gil; Shin, Sang-Chul

    2007-09-01

    Commercial plant essential oils from 26 plant species were tested for their nematicidal activities against the pinewood nematode, Bursaphelenchus xylophilus. Good nematicidal activity against B. xylophilus was achieved with essential oils of ajowan (Trachyspermum ammi), allspice (Pimenta dioica) and litsea (Litsea cubeba). Analysis by gas chromatography-mass spectrometry led to identification of 12, 6 and 16 major compounds from ajowan, allspice and litsea oils, respectively. These compounds from three plant essential oils were tested individually for their nematicidal activities against the pinewood nematode. LC(50) values of geranial, isoeugenol, methyl isoeugenol, eugenol, methyl eugenol and neral against pine wood nematodes were 0.120, 0.200, 0.210, 0.480, 0.517 and 0.525 mg/ml, respectively. The essential oils described herein merit further study as potential nematicides against the pinewood nematode.

  12. New insights into the phylogeny and worldwide dispersion of two closely related nematode species, Bursaphelenchus xylophilus and Bursaphelenchus mucronatus.

    Directory of Open Access Journals (Sweden)

    Filipe Pereira

    Full Text Available The pinewood nematode, Bursaphelenchus xylophilus, is one of the greatest threats to coniferous forests worldwide, causing severe ecological damage and economic loss. The biology of B. xylophilus is similar to that of its closest relative, B. mucronatus, as both species share food resources and insect vectors, and have very similar morphological characteristics, although little pathogenicity to conifers has been associated with B. mucronatus. Using both nuclear and mitochondrial DNA markers, we show that B. xylophilus and B. mucronatus form distinct phylogenetic groups with contrasting phylogeographic patterns. B. xylophilus presents lower levels of intraspecific diversity than B. mucronatus, as expected for a species that evolved relatively recently through geographical or reproductive isolation. Genetic diversity was particularly low in recently colonised areas, such as in southwestern Europe. By contrast, B. mucronatus displays high levels of genetic diversity and two well-differentiated clades in both mitochondrial and nuclear DNA phylogenies. The lack of correlation between genetic and geographic distances in B. mucronatus suggests intense gene flow among distant regions, a phenomenon that may have remained unnoticed due to the reduced pathogenicity of the species. Overall, our findings suggest that B. xylophilus and B. mucronatus have different demographic histories despite their morphological resemblance and ecological overlap. These results suggest that Bursaphelenchus species are a valuable model for understanding the dispersion of invasive species and the risks posed to native biodiversity and ecosystems.

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

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    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.

  14. Identifying Virulence-Associated Genes Using Transcriptomic and Proteomic Association Analyses of the Plant Parasitic Nematode Bursaphelenchus mucronatus

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    Zhou, Lifeng; Chen, Fengmao; Pan, Hongyang; Ye, Jianren; Dong, Xuejiao; Li, Chunyan; Lin, Fengling

    2016-01-01

    Bursaphelenchus mucronatus (B. mucronatus) isolates that originate from different regions may vary in their virulence, but their virulence-associated genes and proteins are poorly understood. Thus, we conducted an integrated study coupling RNA-Seq and isobaric tags for relative and absolute quantitation (iTRAQ) to analyse transcriptomic and proteomic data of highly and weakly virulent B. mucronatus isolates during the pathogenic processes. Approximately 40,000 annotated unigenes and 5000 proteins were gained from the isolates. When we matched all of the proteins with their detected transcripts, a low correlation coefficient of r = 0.138 was found, indicating probable post-transcriptional gene regulation involved in the pathogenic processes. A functional analysis showed that five differentially expressed proteins which were all highly expressed in the highly virulent isolate were involved in the pathogenic processes of nematodes. Peroxiredoxin, fatty acid- and retinol-binding protein, and glutathione peroxidase relate to resistance against plant defence responses, while β-1,4-endoglucanase and expansin are associated with the breakdown of plant cell walls. Thus, the pathogenesis of B. mucronatus depends on its successful survival in host plants. Our work adds to the understanding of B. mucronatus’ pathogenesis, and will aid in controlling B. mucronatus and other pinewood nematode species complexes in the future. PMID:27618012

  15. Identifying Virulence-Associated Genes Using Transcriptomic and Proteomic Association Analyses of the Plant Parasitic Nematode Bursaphelenchus mucronatus

    Directory of Open Access Journals (Sweden)

    Lifeng Zhou

    2016-09-01

    Full Text Available Bursaphelenchus mucronatus (B. mucronatus isolates that originate from different regions may vary in their virulence, but their virulence-associated genes and proteins are poorly understood. Thus, we conducted an integrated study coupling RNA-Seq and isobaric tags for relative and absolute quantitation (iTRAQ to analyse transcriptomic and proteomic data of highly and weakly virulent B. mucronatus isolates during the pathogenic processes. Approximately 40,000 annotated unigenes and 5000 proteins were gained from the isolates. When we matched all of the proteins with their detected transcripts, a low correlation coefficient of r = 0.138 was found, indicating probable post-transcriptional gene regulation involved in the pathogenic processes. A functional analysis showed that five differentially expressed proteins which were all highly expressed in the highly virulent isolate were involved in the pathogenic processes of nematodes. Peroxiredoxin, fatty acid- and retinol-binding protein, and glutathione peroxidase relate to resistance against plant defence responses, while β-1,4-endoglucanase and expansin are associated with the breakdown of plant cell walls. Thus, the pathogenesis of B. mucronatus depends on its successful survival in host plants. Our work adds to the understanding of B. mucronatus’ pathogenesis, and will aid in controlling B. mucronatus and other pinewood nematode species complexes in the future.

  16. analysis of a normalized full-length cDNA library from the pinewood ...

    African Journals Online (AJOL)

    SAM

    2014-08-13

    Aug 13, 2014 ... The pinewood nematode (Bursaphelenchus xylophilus) infects pine trees and causes pine wilt ... activity in pine trees is similar to natural infection by ...... Sultana T, Kim J, Lee SH, Han H, Kim S, Min GS, Nadler SA, Park JK.

  17. Understanding pine wilt disease: roles of the pine endophytic bacteria and of the bacteria carried by the disease-causing pinewood nematode.

    Science.gov (United States)

    Proença, Diogo N; Grass, Gregor; Morais, Paula V

    2017-04-01

    Pine wilt disease (PWD) is one of the most destructive diseases in trees of the genus Pinus and is responsible for environmental and economic losses around the world. The only known causal agent of the disease is the pinewood nematode (PWN) Bursaphelenchus xylophilus. Despite that, bacteria belonging to several different genera have been found associated with PWN and their roles in the development of PWD have been suggested. Molecular methodologies and the new era of genomics have revealed different perspectives to the problem, recognizing the manifold interactions between different organisms involved in the disease. Here, we reviewed the possible roles of nematode-carried bacteria in PWD, what could be the definition of this group of microorganisms and questioned their origin as possible endophytes, discussing their relation within the endophytic community of pine trees. The diversity of the nematode-carried bacteria and the diversity of pine tree endophytes, reported until now, is revised in detail in this review. What could signify a synergetic effect with PWN harming the plant, or what could equip bacteria with functions to control the presence of nematodes inside the tree, is outlined as two possible roles of the microbial community in the etiology of this disease. An emphasis is put on the potential revealed by the genomic data of isolated organisms in their potential activities as effective tools in PWD management. © 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  18. The use of real-time polymerase chain reaction with high resolution melting (real-time PCR-HRM) analysis for the detection and discrimination of nematodes Bursaphelenchus xylophilus and Bursaphelenchus mucronatus.

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    Filipiak, Anna; Hasiów-Jaroszewska, Beata

    2016-04-01

    The real-time PCR-HRM analysis was developed for the detection and discrimination of the quarantine nematode Bursaphelenchus xylophilus and Bursaphelenchus mucronatus. A set of primers was designed to target the ITS region of rDNA. The results have demonstrated that this analysis is a valuable tool for differentiation of these both species.

  19. Role of human-mediated dispersal in the spread of the pinewood nematode in China.

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    Christelle Robinet

    Full Text Available BACKGROUND: Intensification of world trade is responsible for an increase in the number of alien species introductions. Human-mediated dispersal promotes not only introductions but also expansion of the species distribution via long-distance dispersal. Thus, understanding the role of anthropogenic pathways in the spread of invading species has become one of the most important challenges nowadays. METHODOLOGY/PRINCIPAL FINDINGS: We analysed the invasion pattern of the pinewood nematode in China based on invasion data from 1982 to 2005 and monitoring data on 7 locations over 15 years. Short distance spread mediated by long-horned beetles was estimated at 7.5 km per year. Infested sites located further away represented more than 90% of observations and the mean long distance spread was estimated at 111-339 km. Railways, river ports, and lakes had significant effects on the spread pattern. Human population density levels explained 87% of the variation in the invasion probability (P<0.05. Since 2001, the number of new records of the nematode was multiplied by a factor of 5 and the spread distance by a factor of 2. We combined a diffusion model to describe the short distance spread with a stochastic, individual based model to describe the long distance jumps. This combined model generated an error of only 13% when used to predict the presence of the nematode. Under two climate scenarios (stable climate or moderate warming, projections of the invasion probability suggest that this pest could expand its distribution 40-55% by 2025. CONCLUSIONS/SIGNIFICANCE: This study provides evidence that human-induced dispersal plays a fundamental role in the spread of the pinewood nematode, and appropriate control measures should be taken to stop or slow its expansion. This model can be applied to Europe, where the nematode had been introduced later, and is currently expanding its distribution. Similar models could also be derived for other species that could be

  20. Mutual influences in growth and reproduction between pine wood nematode Bursaphelenchus xylophilus and bacteria it carries

    Institute of Scientific and Technical Information of China (English)

    ZHAO Boguang; LIU Yutao; LIN Feng

    2006-01-01

    The interactions between pine wood nematode and three bacterium strains isolated from the nematode,Bursaphelenchus xylophilus,which are two strong pathogenic bacterium strains, Pseudomonas fluorescens GcMS-1A and Pseudomonas putida ZpB1-2A and a weak-pathogenic bacterium strain,Pantoea sp.ZM2C,were studied.The result showed that the strong-pathogenic GcM5-1A strain and ZpB 1-2A strain significantly increased fecundity,reproduction rate,and the body volume of the adult nematode.Meanwhile,pine wood nematodes significantly promoted reproduction of the two strong-pathogenic bacterium strains.However,the weak-pathogenic bacterium strain,ZM2C,completely inhibited reproduction of pine wood nematodes.Aseptic pine wood nematodes significantly inhibited reproduction of the strain ZM2C.The results indicated that mutualistic symbiosis exists between pine wood nematodes and the two pathogenic bacteria it carries.The phenomenon showed that the pathogenic bacteria carried by the nematode were not accidentally contaminated,but rather had existed as symbionts of the nematode with which it had coevoluted over a long period.The role of mutualistic symbiosis in the process of pine wilt disease was also discussed.

  1. Nematicidal activity of natural ester compounds and their analogues against pine wood nematode, Bursaphelenchus xylophilus.

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    Seo, Seon-Mi; Kim, Junheon; Koh, Sang-Hyun; Ahn, Young-Joon; Park, Il-Kwon

    2014-09-17

    In this study, we evaluated the nematicidal activity of natural ester compounds against the pine wood nematode, Bursaphelenchus xylophilus, to identify candidates for the development of novel, safe nematicides. We also tested the nematicidal activity of synthesized analogues of these ester compounds to determine the structure-activity relationship. Among 28 ester compounds tested, isobutyl 2-methylbutanoate, 3-methylbutyl 2-methylbutanoate, 3-methylbutyl tiglate, 3-methyl-2-butenyl 2-methylbutanoate, and pentyl 2-methylbutanoate showed strong nematicidal activity against the pine wood nematode at a 1 mg/mL concentration. The other ester compounds showed weak nematicidal activity. The LC50 values of 3-methylbutyl tiglate, isobutyl 2-methylbutanoate, 3-methylbutyl 2-methylbutanoate, 3-methyl-2-butenyl 2-methylbutanoate, and pentyl 2-methylbutanoate were 0.0218, 0.0284, 0.0326, 0.0402, and 0.0480 mg/mL, respectively. The ester compounds described herein merit further study as potential nematicides for pine wood nematode control.

  2. Deciphering the Molecular Variations of Pine Wood Nematode Bursaphelenchus xylophilus with Different Virulence.

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    Xiaolei Ding

    Full Text Available Bursaphelenchus xylophilus is the causative agent of pine wilt disease which has caused huge economic losses in many countries. It has been reported that two forms of pine wood nematodes existed in its native region, i.e., with strong virulence and weak virulence. However, little is known about the molecular differences between the two forms. To better understand their molecular variations, transcriptome and genome sequences of three strongly virulent and one weakly virulent strains were analyzed. We found 238 transcripts and 84 exons which showed notable changes between the two virulent forms. Functional analyses of both differentially expressed transcripts and exons indicated that different virulence strains showed dissimilar nematode growth, reproduction, and oxidoreductase activities. In addition, we also detected a small number of exon-skipping events in B. xylophilus. Meanwhile, 117 SNPs were identified as potential genetic markers in distinguishing the two forms. Four of them were further proved to have undergone allele specific expressions and possibly interrupted the target site of evolutionary conserved B. xylophilus miR-47. These particular SNPs were experimentally verified by including eight additional strains to ensure the validity of our sequencing results. These results could help researchers to better diagnose nematode species with different virulence and facilitate the control of pine wilt disease.

  3. Essential oils as anti-nematode agents and their influence on in vitro nematode

    OpenAIRE

    Faria, Jorge Miguel Silva, 1983-

    2015-01-01

    Tese de doutoramento, Biologia (Biotecnologia), Universidade de Lisboa, Faculdade de Ciências, 2015 Parasitic nematodes are among the most production-limiting plant pests. In Europe, the recent introduction of Bursaphelenchus xylophilus [the pinewood nematode (PWN)] and some species of Meloidogyne has proved damaging to forest ecosystems and crop production. Due to the very laborious and environment-dependent nature of greenhouse or field assays, in vitro host with parasite co-cultures can...

  4. Specific and functional diversity of endophytic bacteria from pine wood nematode Bursaphelenchus xylophilus with different virulence.

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    Wu, Xiao-Qin; Yuan, Wei-Min; Tian, Xiao-Jing; Fan, Ben; Fang, Xin; Ye, Jian-Ren; Ding, Xiao-Lei

    2013-01-01

    Pine wilt disease (PWD) caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, is one of the most devastating diseases of Pinus spp. The PWN was therefore listed as one of the most dangerous forest pests in China meriting quarantine. Virulence of the PWN is closely linked with the spread of PWD. However, main factors responsible for the virulence of PWNs are still unclear. Recently epiphytic bacteria carried by PWNs have drawn much attention. But little is known about the relationship between endophytic bacteria and virulence of B. xylophilus. In this research, virulence of ten strains of B. xylophilus from different geographical areas in six provinces of China and four pine species were tested with 2-year-old seedlings of Pinus thunbergii. Endophytic bacteria were isolated from PWNs with different virulence to investigate the relationship between the bacteria and PWN virulence. Meanwhile, the carbon metabolism of endophytic bacteria from highly and low virulent B. xylophilus was analyzed using Biolog plates (ECO). The results indicated that ten strains of PWNs showed a wide range of virulence. Simultaneously, endophytic bacteria were isolated from 90% of the B. xylophilus strains. The dominant endophytic bacteria in the nematodes were identified as species of Stenotrophomonas, Achromobacter, Ewingella, Leifsonia, Rhizobium, and Pseudomonas using molecular and biochemical methods. Moreover, S. maltophilia, and A. xylosoxidans subsp. xylosoxidans were the predominant strains. Most of the strains (80%) from P. massoniana contained either S. maltophilia, A. xylosoxidans, or both species. There was a difference between the abilities of the endophytic bacteria to utilize carbon sources. Endophytic bacteria from highly virulent B. xylophilus had a relatively high utilization rate of carbohydrate and carboxylic acids, while bacteria from low virulent B. xylophilus made better use of amino acids. In conclusion, endophytic bacteria widely exist in B. xylophilus

  5. Specific and Functional Diversity of Endophytic Bacteria from Pine Wood Nematode Bursaphelenchus Xylophilus with Different Virulence

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    Xiao-Qin Wu, Wei-Min Yuan, Xiao-Jing Tian, Ben Fan, Xin Fang, Jian-Ren Ye, Xiao-Lei Ding

    2013-01-01

    Full Text Available Pine wilt disease (PWD caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus, is one of the most devastating diseases of Pinus spp. The PWN was therefore listed as one of the most dangerous forest pests in China meriting quarantine. Virulence of the PWN is closely linked with the spread of PWD. However, main factors responsible for the virulence of PWNs are still unclear. Recently epiphytic bacteria carried by PWNs have drawn much attention. But little is known about the relationship between endophytic bacteria and virulence of B. xylophilus. In this research, virulence of ten strains of B. xylophilus from different geographical areas in six provinces of China and four pine species were tested with 2-year-old seedlings of Pinus thunbergii. Endophytic bacteria were isolated from PWNs with different virulence to investigate the relationship between the bacteria and PWN virulence. Meanwhile, the carbon metabolism of endophytic bacteria from highly and low virulent B. xylophilus was analyzed using Biolog plates (ECO. The results indicated that ten strains of PWNs showed a wide range of virulence. Simultaneously, endophytic bacteria were isolated from 90% of the B. xylophilus strains. The dominant endophytic bacteria in the nematodes were identified as species of Stenotrophomonas, Achromobacter, Ewingella, Leifsonia, Rhizobium, and Pseudomonas using molecular and biochemical methods. Moreover, S. maltophilia, and A. xylosoxidans subsp. xylosoxidans were the predominant strains. Most of the strains (80% from P. massoniana contained either S. maltophilia, A. xylosoxidans, or both species. There was a difference between the abilities of the endophytic bacteria to utilize carbon sources. Endophytic bacteria from highly virulent B. xylophilus had a relatively high utilization rate of carbohydrate and carboxylic acids, while bacteria from low virulent B. xylophilus made better use of amino acids. In conclusion, endophytic bacteria widely exist

  6. 松材线虫病研究进展%Development of Studies on Pinewood Nematodes Diseases

    Institute of Scientific and Technical Information of China (English)

    潘沧桑

    2011-01-01

    Pinewood nematode diseases caused serious economic loss and severe ecologic disaster. It has been regarded as important inspection object. In our country the disease area has been enlarged to 14 provinces and cities, which caused more than 0. 5 billion dead pine trees and more than 0. 3 million hectare of damaged forests and loss of several hundred billion yuan. There has been some progress on the basic research of such disease in some countries. But much difficulty still exists on the aspect of its prevention and control. According to the actual situation of small team and good parasitological biology base,we get hold of both side of pathogen and control to develop studies,and made innovation on testing artifice and controlling method. As a result, it has been invented and manufactured that nematode early diagnosis tube,speedy isolating machine type XMP-Ⅰ and type XMP-Ⅱ,diseased woad treating apparatus, highly-effective attractant for pine sawyer, pinewood nematode disease early diagnosis system based on " testing tube" , pinewood nematode speedy testing system based on speedy isolating machine and new technique of high-flux testing Monochamus alternatus toting nematodes by pulverization isolating instrument, etc. Of them, six technical fruits have been applied in production practice and would be started to spread. We also identified and described tens species of nematodes parasitic on pine trees.%松材线虫病引发严重经济损失和重大生态灾难,受到各国重视,成为检疫对象.我国疫区已扩大到14省市,致死松树5亿多株.毁林30多万hm2,损失上千亿元.各国在该病的基础研究方面有一些进展,但防控方面仍困难重重.我们从病原和防治这两方面开展研究,在检测手段和防治方法上进行创新,研制了松材线虫早期诊断检测管(简称检测管)、快速分离器Ⅰ型和Ⅱ型、疫木处理器及松墨天牛高效引诱剂、基于检测管的松材线虫病早期诊断体系、基

  7. Morphometric Variation in Pine Wood Nematodes, Bursaphelenchus xylophilus and B. mucronatus, Isolated from Multiple Locations in South Korea

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    Yil-Sung Moon

    2013-09-01

    Full Text Available Intraspecific variation in morphometry of pine wood nematodes Bursaphelenchus xylophilus and B. mucronatus in relation to geographical locations in South Korea was investigated using morphometric characters (body length, a, b and c ratio, stylet length, and spicule length for a male nematode and V (% value for a female nematode. B. xylophilus was isolated from Pinus thunbergii in Jinju (1998, Ulsan (2000, Yangsan (2000, Mokpo (2001 and Jeju (2004, and from P. densiflora in Gumi (2001. B. mucronatus was isolated from P. thunbergii in Jinju (1991 and from P. densiflora in Milyang (2001. The body length of male and female B. xylophilus had the highest coefficient of variability and showed significant differences among geographical locations. The V (% value for female B. xylophilus showed the lowest coefficient of variability, changing little with geographical area and host plant. All morphometric characters in B. mucronatus except for stylet length and female body length showed no significant differences between locations or hosts, suggesting they may not be affected by geographical area or host plant.

  8. Integrated Control on Pinewood Nematode Disease and its Reflections in Shangyu City%上虞市松材线虫病综合防治与思考

    Institute of Scientific and Technical Information of China (English)

    袁娟红; 孟馨卓; 李云康

    2012-01-01

    Various kinds of measures have been taken to control the pinewood nematode disease since its occurrences in 2004 in Shangyu City. These measures include full clear-up of all dead pine trees out of wooded hills, bio-safety heat treatment and utilization of the dis- eased wood, implementation of the forest form improvement project for eliminating pinewood nematode disease and lay-up of trappers and trap trees to kill monochamus ahernatus, etc. Years of work has produced remarkable results and the pine wood nematode disease has been brought under effective control.%上虞市自2004年发生松材线虫病以来积极采取各种防治措施,包括枯死松树全面清理下山,疫木经热处理生产工艺进行除害处理和安全利用,实施松材线虫病除治林相改造工程,挂诱捕器、设饵木消杀松墨天牛等。几年下来除治效果显现,松材线虫病已得到有效控制。

  9. Nematicidal activity of plant essential oils and components from coriander (Coriandrum sativum), Oriental sweetgum (Liquidambar orientalis), and valerian (Valeriana wallichii) essential oils against pine wood nematode (Bursaphelenchus xylophilus).

    Science.gov (United States)

    Kim, Junheon; Seo, Sun-Mi; Lee, Sang-Gil; Shin, Sang-Chul; Park, Il-Kwon

    2008-08-27

    Commercial essential oils from 28 plant species were tested for their nematicidal activities against the pine wood nematode, Bursaphelenchus xylophilus. Good nematicidal activity against B. xylophilus was achieved with essential oils of coriander (Coriandrum sativum), Oriental sweetgum (Liquidambar orientalis), and valerian (Valeriana wallichii). Analysis by gas chromatography-mass spectrometry led to the identification of 26, 11, and 4 major compounds from coriander (Coriandrum sativum), Oriental sweetgum (Liquidambar orientalis), and valerian (Valeriana wallichii) oils, respectively. Compounds from each plant essential oil were tested individually for their nematicidal activities against the pine wood nematode. Among the compounds, benzaldehyde, trans-cinnamyl alcohol, cis-asarone, octanal, nonanal, decanal, trans-2-decenal, undecanal, dodecanal, decanol, and trans-2-decen-1-ol showed strong nematicidal activity. The essential oils described herein merit further study as potential nematicides against the pine wood nematode.

  10. Expression Profiling in Pinus pinaster in Response to Infection with the Pine Wood Nematode Bursaphelenchus xylophilus

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    Daniel Gaspar

    2017-08-01

    Full Text Available Forests are essential resources on a global scale, not only for the ecological benefits, but also for economical and landscape purposes. However, in recent years, a large number of forest species have suffered a serious decline, with maritime pine being one of the most affected. In Portugal, the maritime pine forest has been devastated by the pine wood nematode (PWN, the causal agent of pine wilt disease. In this study, RNA-Seq data was used to characterize the maritime pine response to infection with PWN, by determining the differentially expressed genes and identifying the regulatory networks and pathways associated. The analyses showed clear differences between an early response that occurs immediately after inoculation and a late response that is observed seven days after inoculation. Moreover, differentially expressed genes related to secondary metabolism, oxidative stress and defense against pathogen infection were identified over different time points. These results provide new insights about the molecular mechanisms and metabolic pathways involved in the response of Pinus pinaster against PWN infection, which will be a useful resource in follow-up studies and for future breeding programs to select plants with lower susceptibility to this disease.

  11. [The analysis of climatic and biological parameters for the pest spread risk modelling of the wood nematode species Bursaphelenchus spp. and Devibursaphelenchus teratospicularis (Rhabditida: Aphelenchoidea)].

    Science.gov (United States)

    Ryss, A Y; Mokrousov, M V

    2014-01-01

    Based on the forest woody species wilt areassurvey in Nizhniy Novgorod region in August 2014, the possible factors of the pest spread risk modelling were analysed on six species of the genus Bursaphelenchus and Devibursaphelenchus teratospicularis using six parameters: plant host species, beetle vector species, average temperatures in July and January, annual precipitation. It was concluded that these parameters in the evaluated wilt spots correspond to climatic and biological data of the already published woody plants wilt records in Europe and Asia caused by the same nematode pest species. It was speculated that the annual precipitation of 600 mm and average July temperature of 25 degrees C or higher, are the critical combination that may be used to develop the predicative risk modelling in the forests' and parks' wilt monitoring.

  12. Effects of Endobacterium (Stenotrophomonas maltophilia on Pathogenesis-Related Gene Expression of Pine Wood Nematode (Bursaphelenchus xylophilus and Pine Wilt Disease

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    Long-Xi He

    2016-05-01

    Full Text Available Pine wilt disease (PWD caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus, is responsible for devastating epidemics in pine trees in Asia and Europe. Recent studies showed that bacteria carried by the PWN might be involved in PWD. However, the molecular mechanism of the interaction between bacteria and the PWN remained unclear. Now that the whole genome of B. xylophilus (Bursaphelenchus xylophilus is published, transcriptome analysis is a unique method to study the role played by bacteria in PWN. In this study, the transcriptome of aseptic B. xylophilus, B. xylophilus treated with endobacterium (Stenotrophomonas maltophilia NSPmBx03 and fungus B. xylophilus were sequenced. We found that 61 genes were up-regulated and 830 were down-regulated in B. xylophilus after treatment with the endobacterium; 178 genes were up-regulated and 1122 were down-regulated in fungus B. xylophilus compared with aseptic B. xylophilus. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were used to study the significantly changed biological functions and pathways for these differentially expressed genes. Many pathogenesis-related genes, including glutathinone S-transferase, pectate lyase, ATP-binding cassette transporter and cytochrome P450, were up-regulated after B. xylophilus were treated with the endobacterium. In addition, we found that bacteria enhanced the virulence of PWN. These findings indicate that endobacteria might play an important role in the development and virulence of PWN and will improve our understanding of the regulatory mechanisms involved in the interaction between bacteria and the PWN.

  13. Nematicidal activity of Cry1Ea11 from Bacillus thuringiensis BRC-XQ12 against the pine wood nematode (Bursaphelenchus xylophilus).

    Science.gov (United States)

    Huang, Tianpei; Lin, Qunxin; Qian, Xiaoli; Zheng, Ying; Yao, Junmin; Wu, Huachuan; Li, Mengmeng; Jin, Xin; Pan, Xiaohong; Zhang, Lingling; Guan, Xiong

    2017-09-12

    The nematicidal activity of 92 Bacillus thuringiensis (Bt) strains against the pine wood nematode Bursaphelenchus xylophilus, one of the world's top 10 plant-parasitic nematodes, was determined. The insecticidal crystal proteins (ICPs) from Bt BRC-XQ12 were the most toxic to B. xylophilus with an LC50 of 32.13 μg/mL. Since the ICPs expressed by Bt BRC-XQ12 were closest to Cry1Ea6 and Bt BRC-XQ12 contained four kinds of cry1 subgenes (cry1Aa, cry1Cb, cry1Ea and cry1Ia), Cry1Ea was most likely to be the key active component against the nematode. The 3516 bp cry1Ea11 gene from Bt BRC-XQ12, as designated by the Bt delta-endotoxin nomenclature committee, was expressed in Escherichia coli. Purified Cry1Ea11 showed an LC50 of 32.53 μg/mL and 23.23 μg/mL at 24 h and 48 h with corresponding virulence equations of Y=32.15X + 1.38 (R(2)=0.9951) and Y=34.29X + 3.16 (R(2)=0.9792), respectively. In order to detect the pathway of Bt Cry1Ea11 entering into B. xylophilus, the nematode was fed with NHS-rhodamine-labeled GST-Cry1Ea11. The results of confocal laser scanning microscopy (CLSM) showed that the 159 kDa GST-Cry1Ea11 could be detected in the stylet and the esophageal lumen of the pine wood nematode, indicating that GST-Cry1Ea11 could enter into the nematode through the stylet. As far as we know, no Cry1 proteins have activity against plant-parasitic nematodes before. These results demonstrate that Cry1Ea11 is a promising nematicidal protein for controlling pine wilt disease (PWD) rendered by B. xylophilus, further dramatically broadening the spectrum of Bt ICPs.

  14. Population dynamics of bacteria associated with different strains of the pine wood nematode Bursaphelenchus xylophilus after inoculation in maritime pine (Pinus pinaster).

    Science.gov (United States)

    Roriz, Mariana; Santos, Carla; Vasconcelos, Marta W

    2011-08-01

    For a long time it was thought that Bursaphelenchus xylophilus was the only agent of the pine wilt disease. Recently, it was discovered that there are bacteria associated with the nematodes that contribute to the pathogenesis of this disease, mainly through the release of toxins that promote the death of the pines. Among the species most commonly found, are bacteria belonging to the Bacillus, Pantoea, Pseudomonas and Xanthomonas genera. The main objective of this work was to study the effect of inoculation of maritime pine (Pinus pinaster) with four different nematode isolates, in the bacterial population of nematodes and trees, at different stages of disease progression. The monitoring of progression of disease symptoms was also recorded. Also, the identification of bacteria isolated from the xylem of trees and the surface of nematodes was performed by classical identification methods, by the API20E identification system and by sequencing of bacterial DNA. The results showed that for the symptoms progression, the most striking difference was observed for the pines inoculated with the avirulent isolate, C14-5, which led to a slower and less severe aggravation of symptoms than in pines inoculated with the virulent isolates. In general, it was found that bacterial population, inside the tree, increased with disease progression. A superior bacterial quantity was isolated from pines inoculated with the nematode isolates HF and 20, and, comparatively, few bacteria were isolated from pines inoculated with the avirulent isolate. The identification system API20E was insufficient in the identification of bacterial species; Enterobacter cloacae species was identified in 79% of the isolated bacterial colonies and seven of these colonies could not be identified by this method. Molecular identification methods, through bacterial DNA sequencing, allowed a more reliable identification: eleven different bacterial species within the Bacillus, Citrobacter, Enterobacter, Escherichia

  15. Influence of Bxpel1 Gene Silencing by dsRNA Interference on the Development and Pathogenicity of the Pine Wood Nematode, Bursaphelenchus xylophilus

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    Xiu-Wen Qiu

    2016-01-01

    Full Text Available As the causal agent of pine wilt disease (PWD, the pine wood nematode (PWN, Bursaphelenchus xylophilus, causes huge economic losses by devastating pine forests worldwide. The pectate lyase gene is essential for successful invasion of their host plants by plant-parasitic nematodes. To demonstrate the role of pectate lyase gene in the PWD process, RNA interference (RNAi is used to analyze the function of the pectate lyase 1 gene in B. xylophilus (Bxpel1. The efficiency of RNAi was detected by real-time PCR. The result demonstrated that the quantity of B. xylophilus propagated with control solution treatment was 62 times greater than that soaking in double-stranded RNA (dsRNA after B. xylophilus inoculation in Botrytis cinerea for the first generation (F1. The number of B. xylophilus soaking in control solution was doubled compared to that soaking in Bxpel1 dsRNA four days after inoculation in Pinus thunbergii. The quantity of B. xylophilus was reduced significantly (p < 0.001 after treatment with dsRNAi compared with that using a control solution treatment. Bxpel1 dsRNAi reduced the migration speed and reproduction of B. xylophilus in pine trees. The pathogenicity to P. thunbergii seedling of B. xylophilus was weaker after soaking in dsRNA solution compared with that after soaking in the control solution. Our results suggest that Bxpel1 gene is a significant pathogenic factor in the PWD process and this basic information may facilitate a better understanding of the molecular mechanism of PWD.

  16. In vitro co-cultures of Pinus pinaster with Bursaphelenchus xylophilus: a biotechnological approach to study pine wilt disease.

    Science.gov (United States)

    Faria, Jorge M S; Sena, Inês; Vieira da Silva, Inês; Ribeiro, Bruno; Barbosa, Pedro; Ascensão, Lia; Bennett, Richard N; Mota, Manuel; Figueiredo, A Cristina

    2015-06-01

    Co-cultures of Pinus pinaster with Bursaphelenchus xylophilus were established as a biotechnological tool to evaluate the effect of nematotoxics addition in a host/parasite culture system. The pinewood nematode (PWN), Bursaphelenchus xylophilus, the causal agent of pine wilt disease (PWD), was detected for the first time in Europe in 1999 spreading throughout the pine forests in Portugal and recently in Spain. Plant in vitro cultures may be a useful experimental system to investigate the plant/nematode relationships in loco, thus avoiding the difficulties of field assays. In this study, Pinus pinaster in vitro cultures were established and compared to in vivo 1 year-old plantlets by analyzing shoot structure and volatiles production. In vitro co-cultures were established with the PWN and the effect of the phytoparasite on in vitro shoot structure, water content and volatiles production was evaluated. In vitro shoots showed similar structure and volatiles production to in vivo maritime pine plantlets. The first macroscopic symptoms of PWD were observed about 4 weeks after in vitro co-culture establishment. Nematode population in the culture medium increased and PWNs were detected in gaps of the callus tissue and in cavities developed from the degradation of cambial cells. In terms of volatiles main components, plantlets, P. pinaster cultures, and P. pinaster with B. xylophilus co-cultures were all β- and α-pinene rich. Co-cultures may be an easy-to-handle biotechnological approach to study this pathology, envisioning the understanding of and finding ways to restrain this highly devastating nematode.

  17. Impact of the invasion of pinewood nematode and the following different removal disturbance intensities on the plant diversity of Masson pine community

    Institute of Scientific and Technical Information of China (English)

    SHI Juan; LUO Youqing; SONG Jiying; YAN Xiaosu; JIANG Ping; WANG Yijiao

    2007-01-01

    Reported in this paper are our findings of the study on changes in species diversity of different Masson pine communities after the invasion of Bursaphelenchus xylophilus(Steiner and Buhren)Nickle and subsequent and different removal disturbance management approaches.Based on the results,the species diversity indices for the arbor layers of the different communities can be arranged in the following order(from high to low):1)broad-leaved stand after the removal of all infected pine trees in the pure pine stand in Fuyang;2)lightly infected Masson pine and Schima superba mixed stand in Fuyang;3)uninfected stand mixture of Masson pine and Castanopsis fargesii as a control;4)lightly infested pure Masson pine stand in Fuyang;5)Quercus variables stand formed following the selective removal of infected pine trees from a mixed Masson pine and Q.variables stand in Zhoushan Islands;6)pure young Masson pine stand formed following the removal of all infected pine trees from a pure Masson pine stand;7)pure Liquidambarformosana stand after the removal of infected pine trees from a pure pine stand in Zhoushan Islands;8)a mixed stand consisting of Pinus thunbergii and the Masson pine in Zhoushan Island;and 9)moderately infected Masson pine stand in Zhoushan Islands.All the three diversity indices(R0=richness,H'=Shan-non-Wiener index,and E=evenness)for the shrub layer did not show any significant differences among the various communities except for the pure pine stand in ZhoushanIsland,which had the lowest diversity.The three indices for the herb layer of the pure young Masson pine,Q.variables stand,and L.formosana stand were higher than that of other stands.The integrated analysis showed that the Masson pine forest in different geographical situations and extent of damage had distinct disparity,just as in different disturbance degrees and restoring manners.We created the"index of disturbing intensity of stump and fallen woods"(IDISFW)to represent thedegree of disturbance of tree

  18. 4个蠕虫埃斯特菌株的产孢能力及对松材线虫的侵染活力%Variation in Sporulation of Four Esteya vermicola Isolates and their Infectivity Against Pinewood Nematode

    Institute of Scientific and Technical Information of China (English)

    王海华; 褚洪龙; 谢清哲; 豆青; 冯欢; 杨超; 王春燕

    2016-01-01

    侵染孢子的数量最多,对松材线虫的侵染力也为最高,因此可选用于未来松萎蔫病生防制剂的开发和应用。%Objective]As one of the most serious worldwide conifer diseases,pine wilt disease caused by pinewood nematode ( PWN) ,Bursaphelenchus xylophilus,has brought irreparable damages to the forest ecosystems and industries with great economic and environmental losses. Esteya vermicola is the first recorded endoparasitic fungus of PWN,has exhibited high infectivity and potential as a biocontrol agent of pine wilt disease. Through the comparison among different E. vermicola isolates in their morphological characteristics,sporulation and infectivity against PWN,the excellent isolate can be screened out and to be developed as the biocontrol agent of pine wilt disease. This work will provide useful knowledge and information for the biocontrol of devastating pine wilt disease in the future.[Method]Four E. vermicola isolates ( ATCC 74485 and CNU 120806 from Asia, CBS 115803 and CBS 100821 from Europe ) were compared systemically in terms of the growth,sporulation and infectivity against PWN with three most commonly used nature culture media for the nematophagous fungi ( potato dextrose agar,corn meal agar and 2% water agar,served as an example of carbon nutrition-rich,-weak and -poor culture media,respectively) . In addition,the influences of carbon sources on the growth,sporulation and infectivity of four isolates also were simply analyzed.[Result]Four E. vermicola isolates showed obvious variation on different culture media in terms of the colonial feature,growth speed,sporulation and infectivity, although they shared the basic morphological characteristics and nematode infection process. The nutrition of culture medium showed different influences on the growth,sporulation and infectivity of different isolates,had a markedly positive correlation with the growth and sporulation of E. vermicola,but a negative correlation with the

  19. Application of Esteya vermicola,an endoparasitic fungus of the pinewood nematode,for controlling pine wilt disease%利用松材线虫的内寄生真菌Esteya vermicola防治松萎蔫病

    Institute of Scientific and Technical Information of China (English)

    Chang Keun Sung; Zhe Ming Fang; Chun Yan Wang; Zhen Wang

    2011-01-01

    Esteya vermicola, the first endoparasitic fungus is founded to be associated with the pinewood nematode ( PWN), shows great potential as a biological control agent for combating the devastating pine wilt disease. Recently, new E. vermicola strains have been isolated from soil in Korea. These straits have two different types of conidingenous cells and conidia. However, only the lunate conidia are adhesive and can attach to the cuticle of the PWN and cause subsequent infection. In vitro, E. vermicola kills and colonizes almost all the tested pinewood nematode isolates within 4-5 days and is highly infective. However, to determine its potencial as a biocontrol agent for the PWN studies are needed on the feasibility of using the fungus. Isolation results and the taxonomic status of E. vermicola suggest that it is associated with vector beetles and affected trees.Consequently ,greenhouse tests were done using the fungus to control the PWN and during the last 2 years field tests have been done in mountainous areas. Three application methods were used in the experiments :suspension spraying, trunk injection into trees,and applying infected nematodes onto trees. The results showed that E. vermicola grew into pine seedlings and successfully infected PWNs and E. vermicola mycelium were observed within pine trees.Presently, studies are being made to evuluate the application and formulation of E. vermicola as a commercial biocontrol agent.%Esteya vermicola是首次发现的松材线虫的内寄生真菌.最近从韩国土壤中发现了该菌的一个新菌株.该菌株能产生两种孢子,并能在4~5 d内感染几乎所有测试的松材线虫分离物.最近2年里在韩国进行了该菌株的温室和林间的接种试验,使用了3种方法进行接种,即喷施、注干和将感染的松材线虫接种到松树上.结果证明,该菌在松树幼树中生长并侵染到接种松树中的松材线虫,在松树中也观察到该菌的存在.目前,对该菌的使用方

  20. Pathogenicity of aseptic Bursaphelenchus xylophilus.

    Science.gov (United States)

    Zhu, Li-hua; Ye, Jianren; Negi, Sapna; Xu, Xu-ling; Wang, Zhang-li; Ji, Jin-yi

    2012-01-01

    Pine wilt is a disease of pine (Pinus spp.) caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus. However, the pathogenic mechanism of pine wilt disease (PWD) remains unclear. Although the PWN was thought to be the only pathogenic agent associated with this disease, a potential role for bacterial symbionts in the disease process was recently proposed. Studies have indicated that aseptic PWNs do not cause PWD in aseptic pine trees, while PWNs associated with bacteria cause wilting symptoms. To investigate the pathogenicity of the PWN and its associated bacteria, 3-month-old microcuttings derived from certain clones of Pinus densiflora Siebold & Zucc. produced in vitro were inoculated under aseptic conditions with aseptic PWNs, non-aseptic PWNs and bacteria isolated from the nematodes. Six-month-old aseptic P. densiflora microcuttings and 7-month-old P. massoniana seedlings were also inoculated under aseptic conditions with aseptic PWNs and non-aseptic PWNs. The results showed that the aseptic microcuttings and seedlings inoculated with aseptic PWNs or non-aseptic PWNs wilted, while those inoculated with bacterial isolates did not wilt. Nematodes were recovered from wilted microcuttings and seedlings inoculated with aseptic PWNs and non-aseptic PWNs, and the asepsis of nematodes recovered from aseptic PWN-inoculated microcuttings and seedlings was reconfirmed by culturing them in NB liquid medium at 30°C for more than 7 days. Taken together, the results indicate that the asepsis of PWN did not cause the loss of pathogenicity.

  1. Pathogenicity of aseptic Bursaphelenchus xylophilus.

    Directory of Open Access Journals (Sweden)

    Li-hua Zhu

    Full Text Available Pine wilt is a disease of pine (Pinus spp. caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus. However, the pathogenic mechanism of pine wilt disease (PWD remains unclear. Although the PWN was thought to be the only pathogenic agent associated with this disease, a potential role for bacterial symbionts in the disease process was recently proposed. Studies have indicated that aseptic PWNs do not cause PWD in aseptic pine trees, while PWNs associated with bacteria cause wilting symptoms. To investigate the pathogenicity of the PWN and its associated bacteria, 3-month-old microcuttings derived from certain clones of Pinus densiflora Siebold & Zucc. produced in vitro were inoculated under aseptic conditions with aseptic PWNs, non-aseptic PWNs and bacteria isolated from the nematodes. Six-month-old aseptic P. densiflora microcuttings and 7-month-old P. massoniana seedlings were also inoculated under aseptic conditions with aseptic PWNs and non-aseptic PWNs. The results showed that the aseptic microcuttings and seedlings inoculated with aseptic PWNs or non-aseptic PWNs wilted, while those inoculated with bacterial isolates did not wilt. Nematodes were recovered from wilted microcuttings and seedlings inoculated with aseptic PWNs and non-aseptic PWNs, and the asepsis of nematodes recovered from aseptic PWN-inoculated microcuttings and seedlings was reconfirmed by culturing them in NB liquid medium at 30°C for more than 7 days. Taken together, the results indicate that the asepsis of PWN did not cause the loss of pathogenicity.

  2. Study of population dynamics of bacteria associated with pine wood nematode after inoculation with different strains of Bursaphelenchus xylophilus in maritime pine (Pinus pinaster)

    OpenAIRE

    Costa, Mariana Roriz Lemos

    2011-01-01

    Durante algum tempo pensou-se que o Bursaphelenchus xylophilus era o único agente etiológico da doença do nemátode da madeira do pinheiro. Recentemente, descobriu-se que existem bactérias associadas ao nemátode que contribuem para a patogénese desta doença, sobretudo através da libertação de toxinas que promovem a morte dos pinheiros. De entre as espécies mais comummente encontradas estão bactérias pertencentes aos géneros Bacillus, Pantoea, Pseudomonas e Xanthomonas. Este trabalho teve...

  3. 葡萄牙松材线虫与其媒介昆虫之间的互作%Interactions of the pine wood nematode (Bursaphelenchus xylophilus)with its vector in Portugal

    Institute of Scientific and Technical Information of China (English)

    Pedro Miguel Naves; Luís Bonifácio; Edmundo Sousa

    2011-01-01

    The most important aspects of the interactions be-tween the pine wood nematode ( PWN) ( Bursaphelenchus xylo-philus) and its local insect vector,the pine sawyer Monocham-us galloprovirzcialis have been recently studied for the first timein Portugal and Europe.Inside the dead pines the pinewoodnematode was found to associate with the callow adults in thepupal chambers,just before the insects' emergence.The nema-todes are more abundant on the thoracic region of the insects,namely on the meta-thorax segment.After emergence,trans-mission of the PWN into new hosts occurs by the feeding activi-ty of the beetles,being more frequent during the six weeks af-ter emergence.Nematode transmission also occurs by the ovi-position activity of the female beetles,although with less fre-quency and success.%对松材线虫与其在葡萄牙和欧洲的媒介昆虫樟子松墨天牛(Monochamus galloprovincialis)进行了首次研究.在病死木中发现,松材线虫在天牛刚羽化时聚集在蛹室中,线虫主要集中在天牛的后胸部.天牛羽化后6周内,松材线虫主要在天牛成虫补充营养时进入新寄主树,其次在天牛产卵时也会进入寄主树.总的看来,松材线虫在欧洲与其携带天牛之间互作与其在亚洲与松墨天牛及在北美与卡来罗纳墨天牛之间的关系十分相似.经研究,影响线虫与天牛携带关系的因子有内源和外源两类因子,如化学气味和各种信号.但是,其他多数因子尚未了解.研究影响线虫与天牛携带关系的因子将有助于了解两种生物密切关系的内在机制,并有助于研发出新的防控方法.

  4. 基于松材线虫全基因组序列的SSR标记开发%Development of simple sequence repeats base on pine wood nematode (Bursaphelenchus xylophilus) genome sequence

    Institute of Scientific and Technical Information of China (English)

    许峻荣; 吴小芹; 刘云; 叶建仁

    2014-01-01

    为了研究松材线虫在我国的群体遗传关系及传播路径,获得更为稳定的松材线虫分子标记,使用MISA软件对松材线虫全基因组10432条DNA片段进行搜索,共获得95个gSSR位点。其中,二核苷酸重复出现频率最高,占全部SSR位点的66�3%。依据所有gSSR位点共设计出36对引物,以1份松材线虫DNA pooling(包含我国46个不同地理来源的松材线虫虫株DNA)为模板进行PCR,产物由QIAxcel全自动凝胶电泳分析系统检测,获得17对可能具有多态性的gSSR引物。进一步对这17对引物的PCR产物进行单克隆试验并测序,BioEdit软件拼接比对结果表明,其中9对确实具有多态性。%To develop more stable molecular marker, SSR marker base on pine wood nematode ( Bursaphelenchus xylo-philus) whole genome sequences was discussed for researching the relationship of population genetic and travel route ac-curately. Ninety-five SSR loci were searched from a total of 10 432 DNA fragments of B. xylophilus by MISA. In the gSSRs, the dinucleotide repeat motifs were the most abundant (66.3%). Thirty-six pairs of primers were designed, and verified with one peace of B.xylophilus DNA pooling sample (46 DNA samples of isolates from different geographic origin contained) for PCR. The products detected by QIAxcellautomatic gel electrophoresis analysis system showed that 17 pairs of primers had potential polymorphism. Further, nine pairs of the primers showed polymorphism, which tested by mono-clonal sequencing and spliced by BioEdit, and which provided foundation for studying population genetic of B.xylophilus.

  5. Study on the Sustainable Management of Pine Wood Nematode (Bursaphelenchus xylophilis) in Old Epidemic Areas%老疫区松材线虫病持续控制技术研究

    Institute of Scientific and Technical Information of China (English)

    范军祥; 黄焕华; 钱明惠; 黄咏槐; 武海卫

    2011-01-01

    2005~2009年在广州市松材线虫病老疫区系统开展了疑似病死松树的早期诊断、应用引诱剂和林间释放花绒寄甲控制松褐天牛、清理病死木套袋熏蒸和疫区松林植物群落结构改造等持续控制技术研究.结果表明:疫区内松树枯死木松材线虫的检出率为22.1%~55.4%.诱到松褐天牛成虫19 853头,每个诱捕器的诱虫量为14.06~24.80头/年.释放花绒寄甲成虫1 115头,寄生率为9.21%~60.00%.清理枯死木14 769株,熏蒸袋内的松褐天牛死亡率达到99.5%以上.在松林内套种39种阔叶树共112 000株,改善了松林的植物群落结构,提高了松林对松褐天牛及松材线虫病的抗性.%The sustainable control technology research on pine wood nematode ( Bursaphelenchus xylophilis)and pine sawyer beetle ( Monochamus alternatus) have been carried out in Guangzhou old epidemic areas from 2005 to 2009. The main technical measures including ( 1 ) Early diagnosis of pine wilt disease; (2) Control and monitor the adults M. alternatus by attractant; (3) Control pine sawyer beetles by releasing Dastarcus helophoroides; (4)Clean up dead trees and extinguish pests in woodlands; (5) Modification on the plant community structure in pine forest. The results showed that the detection rate of B. xylophilis from dead trees is 22.1% ~55.4%; 19 583 adults of M. alternatus have been trap in the test area, and 14.06 ~24.80 adults per trap set in a year; 1 115 D.helophoroides were released in the pine forest, and the parasitism rate is 9.21% ~ 60.00%; 14 769 dead trees have been clean up, the mortality rate of M. alternatus larva or pupae is up to 99.5%; 112 000 broadleaf trees (39 species) were planted in the pine forests, the plant community gets higher resistance to pine sawyer and pine wood nematode disease.

  6. Searching for resistance genes to Bursaphelenchus xylophilus using high throughput screening

    Directory of Open Access Journals (Sweden)

    Santos Carla S

    2012-11-01

    Full Text Available Abstract Background Pine wilt disease (PWD, caused by the pinewood nematode (PWN; Bursaphelenchus xylophilus, damages and kills pine trees and is causing serious economic damage worldwide. Although the ecological mechanism of infestation is well described, the plant’s molecular response to the pathogen is not well known. This is due mainly to the lack of genomic information and the complexity of the disease. High throughput sequencing is now an efficient approach for detecting the expression of genes in non-model organisms, thus providing valuable information in spite of the lack of the genome sequence. In an attempt to unravel genes potentially involved in the pine defense against the pathogen, we hereby report the high throughput comparative sequence analysis of infested and non-infested stems of Pinus pinaster (very susceptible to PWN and Pinus pinea (less susceptible to PWN. Results Four cDNA libraries from infested and non-infested stems of P. pinaster and P. pinea were sequenced in a full 454 GS FLX run, producing a total of 2,083,698 reads. The putative amino acid sequences encoded by the assembled transcripts were annotated according to Gene Ontology, to assign Pinus contigs into Biological Processes, Cellular Components and Molecular Functions categories. Most of the annotated transcripts corresponded to Picea genes-25.4-39.7%, whereas a smaller percentage, matched Pinus genes, 1.8-12.8%, probably a consequence of more public genomic information available for Picea than for Pinus. The comparative transcriptome analysis showed that when P. pinaster was infested with PWN, the genes malate dehydrogenase, ABA, water deficit stress related genes and PAR1 were highly expressed, while in PWN-infested P. pinea, the highly expressed genes were ricin B-related lectin, and genes belonging to the SNARE and high mobility group families. Quantitative PCR experiments confirmed the differential gene expression between the two pine species

  7. Framework for modelling economic impacts of invasive species, applied to pine wood nematode in Europe.

    Directory of Open Access Journals (Sweden)

    Tarek Soliman

    Full Text Available BACKGROUND: Economic impact assessment of invasive species requires integration of information on pest entry, establishment and spread, valuation of assets at risk and market consequences at large spatial scales. Here we develop such a framework and demonstrate its application to the pinewood nematode, Bursaphelenchus xylophilus, which threatens the European forestry industry. The effect of spatial resolution on the assessment result is analysed. METHODOLOGY/PRINCIPAL FINDINGS: Direct economic impacts resulting from wood loss are computed using partial budgeting at regional scale, while impacts on social welfare are computed by a partial equilibrium analysis of the round wood market at EU scale. Substantial impacts in terms of infested stock are expected in Portugal, Spain, Southern France, and North West Italy but not elsewhere in EU in the near future. The cumulative value of lost forestry stock over a period of 22 years (2008-2030, assuming no regulatory control measures, is estimated at €22 billion. The greatest yearly loss of stock is expected to occur in the period 2014-2019, with a peak of three billion euros in 2016, but stabilizing afterwards at 300-800 million euros/year. The reduction in social welfare follows the loss of stock with considerable delay because the yearly harvest from the forest is only 1.8%. The reduction in social welfare for the downstream round wood market is estimated at €218 million in 2030, whereby consumers incur a welfare loss of €357 million, while producers experience a €139 million increase, due to higher wood prices. The societal impact is expected to extend to well beyond the time horizon of the analysis, and long after the invasion has stopped. CONCLUSIONS/SIGNIFICANCE: Pinewood nematode has large economic consequences for the conifer forestry industry in the EU. A change in spatial resolution affected the calculated directed losses by 24%, but did not critically affect conclusions.

  8. Identification of Nematicidal Constituents of Notopterygium incisum Rhizomes against Bursaphelenchus xylophilus and Meloidogyne incognita

    OpenAIRE

    Gai Liu; Daowan Lai; Qi Zhi Liu; Ligang Zhou; Zhi Long Liu

    2016-01-01

    During a screening program for new agrochemicals from Chinese medicinal herbs, the ethanol extract of Notopterygium incisum rhizomes was found to possess strong nematicidal activity against the two species of nematodes, Bursaphelenchus xylophilus and Meloidogyne incognita. Based on bioactivity-guided fractionation, the four constituents were isolated from the ethanol extract and identified as columbianetin, falcarindiol, falcarinol, and isoimperatorin. Among the four isolated constituents, tw...

  9. Investigation of Terahertz Spectral Signatures of DNA of Pine Wood Nematode

    OpenAIRE

    Ling Jiang; Chun Li; Lin Huang; Zhenwei Zhang; Cunlin Zhang; Yunfei Liu

    2012-01-01

    In this study, we present the fingerprint characteristic about the identification of harmful Bursaphelenchus xylophilus (Bx) nematode and harmless Bursaphelenchus mucronatus (Bm) nematode by applying terahertz spectroscopic techniques. We measure the transmission of the Deoxyribose Nucleic Acid (DNA) of the Bx and the Bm samples and their corresponding Polymerase Chain Reaction (PCR) amplification segments of the DNA molecules by the Terahertz Domain Spectroscopy (THz-TDS) and the Fourier Tra...

  10. BME-based spatiotemporal analysis of damage to pine wood nematode Bursaphelenchus xylophilus in Zijin Mountain%基于贝叶斯最大熵模型的紫金山松材线虫危害程度时空分析

    Institute of Scientific and Technical Information of China (English)

    李明阳; 张晓利; 刘方; 陈溢南

    2012-01-01

    【Objective】 The objective of spatiotemporal prediction of damage from pine wood nematode Bursaphelenchus xylophilus at Zijin Mountain National Forest Park is to provide scientific basis to make plan to protect forest.【Method】 The observation data of 96 fixed points of pine wilt disease at scenic forest in Zijin Mountain National Forest Park from 2004 to 2008 were chosen as the main source of information,together with the related auxiliary information of six ecological environmental factors.Bayesian maximum entropy(BME) method was applied to do spatiotemporal analysis of damage to pine wood nematode.【Result】 From 2004 to 2008,the average number of dead pine trees at observation points of pine wilt disease in Zijin Mountain National Forest Park decreased from 29.96 to 8.17.From 2008 to 2012,the outbreak of pine wood nematode was alleviated in western park and controlled in central park,but still serious in the eastern park,resulting in lower connectivity between points with high number of dead trees.Spatial cluster of dead trees at observation points of pine wilt disease in 2012 indicates that the transportation inconvenient mountain region with large area of old and high volume pine trees will suffer more severely from pine wood nematode and more attention should be paid to prevention and control.【Conclusion】 With GIS-based BME method and a small amount of fixed-point observation data,spatiotemporal analysis can be conducted to predict damage from pine wood nematode,which can provide a scientific basis for prevention and control of invasion from major forest pests.%【目的】对紫金山国家森林公园松材线虫危害程度进行时空预测,旨在为森林病虫害防治规划的制定提供科学依据。【方法】以2004-2008年紫金山国家森林公园风景林96个松材线虫病疫点定点观测数据为主要信息源,与松材线虫危害程度相关的6个生态环境因子作为辅助信息源,采用GIS平台及贝叶斯最

  11. Variabilities of two Drechslerella dactyloides isolates in Korea and high predacity against Bursaphelenchus xylophilus.

    Science.gov (United States)

    Wang, Zhen; Wang, Chun-Yan; Gu, Li-Juan; Sun, Bai-Shen; Zhang, Dong-Liang; Liu, Lei; Lee, Mi-Ra; Wang, Chun-Ling; Li, Zheng; Mo, Eun-Kyung; Sung, Chang-Keun

    2011-02-01

    Drechslerella dactyloides generates elongate ellipsoid conidia and three-celled rings. Recently, Drechslerella dactyloides CNU 091025 and CNU 091026 were isolated in Korea, which generated elongate ellipsoid, Y-shaped and reaphook-shaped conidia, three-celled rings and fishhook-shaped traps. Therefore, molecular phylogenetic analysis, morphological variability, and nematode capturing ability were tested in this study. CNU 091025 generated two-celled or three-celled Y-shaped conidia, reaphook-shaped conidia, and elongate ellipsoid conidia, 17.2, 40.9, and 41.9%, respectively. Some fishhook-shaped rings connecting together formed two-dimensional web. Both fungi showed high trap-forming and nematode-capturing ability; especially CNU 091026 captured 100% Bursaphelenchus xylophilus within 24 h after inoculation.

  12. Newly Discovered Transmission Pathway of Bursaphelenchus xylophilus from Males of the Beetle Monochamus alternatus to Pinus densiflora Trees via Oviposition Wounds.

    Science.gov (United States)

    Arakawa, Yoh; Togashi, Katsumi

    2002-12-01

    The transmission of Bursaphelenchus xylophilus from Monochamus alternatus males to Pinus densiflora trees via oviposition wounds has been determined. Nematode-infested males, with mandibles fixed experimentally to prevent feeding, were placed for 48 hours with pine bolts containing oviposition wounds that had been made by nematode-free females. After removal of the nematode-infested males, the pine bolts were held for 1 month and then examined for the presence of nematodes. Reproducing nematode populations were recovered from pine bolts that were exposed to male beetles carrying a high number of nematodes. No reproducing nematode population could be recovered from pine bolts exposed to beetles with a small number of nematodes. Nematode reproduction in the pine bolts was not related to the number of oviposition wounds per bolt. Fourth-stage dispersal B. xylophilus juveniles, collected from beetle body surfaces, were inoculated on pine bolt bark 0, 5, 10, and 15 cm away from a single artificial, small hole. These dauer juveniles successfully entered some bolts. The probability of successful nematode reproduction decreased with increased distance between inoculation point and artificial hole. The results indicated that B. xylophilus can move a significant distance to oviposition wounds along the bark surface and enter a tree via the wounds. The new transmission pathway is considered important for the nematode to persist in pine forests such as in North America where pine wilt disease does not occur.

  13. Identification of Nematicidal Constituents of Notopterygium incisum Rhizomes against Bursaphelenchus xylophilus and Meloidogyne incognita

    Directory of Open Access Journals (Sweden)

    Gai Liu

    2016-09-01

    Full Text Available During a screening program for new agrochemicals from Chinese medicinal herbs, the ethanol extract of Notopterygium incisum rhizomes was found to possess strong nematicidal activity against the two species of nematodes, Bursaphelenchus xylophilus and Meloidogyne incognita. Based on bioactivity-guided fractionation, the four constituents were isolated from the ethanol extract and identified as columbianetin, falcarindiol, falcarinol, and isoimperatorin. Among the four isolated constituents, two acetylenic compounds, falcarindiol and falcarinol (2.20–12.60 μg/mL and 1.06–4.96 μg/mL, respectively exhibited stronger nematicidal activity than two furanocoumarins, columbianetin, and isoimperatorin (21.83–103.44 μg/mL and 17.21–30.91 μg/mL, respectively against the two species of nematodes, B. xylophilus and M. incognita. The four isolated constituents also displayed phototoxic activity against the nematodes. The results indicate that the ethanol extract of N. incisum and its four isolated constituents have potential for development into natural nematicides for control of plant-parasitic nematodes.

  14. Identification of Nematicidal Constituents of Notopterygium incisum Rhizomes against Bursaphelenchus xylophilus and Meloidogyne incognita.

    Science.gov (United States)

    Liu, Gai; Lai, Daowan; Liu, Qi Zhi; Zhou, Ligang; Liu, Zhi Long

    2016-09-23

    During a screening program for new agrochemicals from Chinese medicinal herbs, the ethanol extract of Notopterygium incisum rhizomes was found to possess strong nematicidal activity against the two species of nematodes, Bursaphelenchus xylophilus and Meloidogyne incognita. Based on bioactivity-guided fractionation, the four constituents were isolated from the ethanol extract and identified as columbianetin, falcarindiol, falcarinol, and isoimperatorin. Among the four isolated constituents, two acetylenic compounds, falcarindiol and falcarinol (2.20-12.60 μg/mL and 1.06-4.96 μg/mL, respectively) exhibited stronger nematicidal activity than two furanocoumarins, columbianetin, and isoimperatorin (21.83-103.44 μg/mL and 17.21-30.91 μg/mL, respectively) against the two species of nematodes, B. xylophilus and M. incognita. The four isolated constituents also displayed phototoxic activity against the nematodes. The results indicate that the ethanol extract of N. incisum and its four isolated constituents have potential for development into natural nematicides for control of plant-parasitic nematodes.

  15. Development of a pathway model to assess the exposure of European pine trees to pine wood nematode via the trade of wood

    NARCIS (Netherlands)

    Douma, J.C.; Werf, Van Der W.; Hemerik, L.; Magnusson, C.; Robinet, C.

    2017-01-01

    Pine wood nematode (PWN), Bursaphelenchus xylophilus, is a threat for pine species (Pinus spp.) throughout the world. The nematode is native to North America, and invaded Japan, China, Korea, and Taiwan, and more recently Portugal and Spain. PWN enters new areas through trade in wood products. Once

  16. Ecological survey of the native pinewoods of Scotland 1971

    Science.gov (United States)

    Wood, Claire M.; Bunce, Robert G. H.

    2016-05-01

    In 1971, a comprehensive ecological survey of the native pinewoods of Scotland was carried out by the Institute of Terrestrial Ecology. The survey was initiated as a consequence of growing concern about the status of the pinewood resource. Since the twentieth century, this unique habitat is widely recognised, not only by ecologists for its inherent biodiversity but also by the general public for its cultural and amenity value. The survey, utilising demonstrably repeatable methods, collected information on ground flora, soils, forest structure and also general site information from the major 27 sites of the 35 sites identified as truly native pinewoods in Scotland. The results from the survey prompted the organisation of an international symposium in 1975, which set the conservation agenda for the old Caledonian pinewoods. The data collected during the 1971 survey are now publicly available via the following DOI: doi:10/7xb ("Habitat, vegetation, tree and soil data from Native Pinewoods in Scotland, 1971"). Although the data are now 44 years old, the repeatable methods will allow for a resurvey to take place, in order to assess changes in the vegetation, habitats and tree composition in a statistically robust manner.

  17. Suggestions on management measures of pine forest ecosystems invaded by Bursaphelenchus xylophilus

    Institute of Scientific and Technical Information of China (English)

    SHI Juan; LUO You-qing; XIA Nai-bin; WU Hai-wei; SONG Ji-ying

    2008-01-01

    Pine wood nematode (PWN), Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle is an important invasive alien species in forests of China and has become one of the most destructive forest diseases. In order to improve the resistance and resilience of pine forest ecosystems against B. xylophilus invasion and make the pine forest ecosystem more timely responsive to PWN invasion,we made some recommendations based on five years of intensive observations. We advocate a set of management measures with the theme "Prevention is priority, but integrated with curative techniques and ecological resilience" on the pine forest ecosystem invaded by B. xylophilus; details of accurate measures are proposed. The aim is to discover the underlying problems of present pine forest ecosystems and to take, correspondingly, administrative measures and strategies, which will encourage the pine forest ecosystem to develop in a benign way.

  18. Screening and Functional Analysis of the Peroxiredoxin Specifically Expressed in Bursaphelenchus xylophilus—The Causative Agent of Pine Wilt Disease

    Directory of Open Access Journals (Sweden)

    Han-Yu Fu

    2014-06-01

    Full Text Available The pine wood nematode, Bursaphelenchus xylophilus, is the causal agent of pine wilt disease. Accurately differentiating B. xylophilus from other nematodes species, especially its related species B. mucronatus, is important for pine wood nematode detection. Thus, we attempted to identify a specific protein in the pine wood nematode using proteomics technology. Here, we compared the proteomes of B. xylophilus and B. mucronatus using Two-dimensional gel electrophoresis (2-DE and matrix-assisted laser desorption/ionization -time-of-flight/time-of-flight (MALDI-TOF/TOF-MS technologies. In total, 15 highly expressed proteins were identified in B. xylophilus compared with B. mucronatus. Subsequently, the specificity of the proteins identified was confirmed by PCR using the genomic DNA of other nematode species. Finally, a gene encoding a specific protein (Bx-Prx was obtained. This gene was cloned and expressed in E. coli. The in situ hybridisation pattern of Bx-Prx showed that it was expressed strongly in the tail of B. xylophilus. RNAi was used to assess the function of Bx-Prx, the results indicated that the gene was associated with the reproduction and pathogenicity of B. xylophilus. This discovery provides fundamental information for identifying B. xylophilus via a molecular approach. Moreover, the purified recombinant protein has potential as a candidate diagnostic antigen of pine wilt disease, which may lead to a new immunological detection method for the pine wood nematode.

  19. Lipid accumulation from pinewood pyrolysates by rhodosporidium diobovatum and chlorella vulgaris for biodiesel production

    NARCIS (Netherlands)

    Luque, L.; Orr, V.C.A.; Chen, S.; Westerhof, R.J.M.; Oudenhoven, S.R.G; Rossum, van G.; Kersten, S.R.A.; Berruti, F.; Rehmann, L.

    2016-01-01

    This study evaluated the suitability of pinewood pyrolysates as a carbon source for lipid production and cultivation of the oleaginous yeast Rhodosporidium diobovatum and the microalgae Chlorella vulgaris. Thermal decomposition of pinewood and fractional condensation were used to obtain an oil rich

  20. Lipid accumulation from pinewood pyrolysates by rhodosporidium diobovatum and chlorella vulgaris for biodiesel production

    NARCIS (Netherlands)

    Luque, L.; Orr, V.C.A.; Chen, S.; Westerhof, Roel Johannes Maria; Oudenhoven, Stijn; van Rossum, G.; Kersten, Sascha R.A.; Berruti, F.; Rehmann, L.

    2016-01-01

    This study evaluated the suitability of pinewood pyrolysates as a carbon source for lipid production and cultivation of the oleaginous yeast Rhodosporidium diobovatum and the microalgae Chlorella vulgaris. Thermal decomposition of pinewood and fractional condensation were used to obtain an oil rich

  1. Screening for Nemaicidal Activity of Some Chinese Plant Extracts against Plant Parasitic Nematodes, Bursaphelenchus xylophilus, Meloidogyne arenaria and Hirschmanniella oryzae%植物抽提物对几种植物病原线虫的杀线活性筛选

    Institute of Scientific and Technical Information of China (English)

    文艳华; 冯志新; 徐汉虹; 陈立

    2001-01-01

    Extracts of 14 Chinese plants (belong to 10 fami lies in Hubei,Shanxi and Guangdong Provinces, China) were assessed f or nematicidal activity against Bursaphelenchus xylophilus using a fungal-f eedin g method in vitro. Some of 14 plant extracts were also assessed for nematicidal activity against Meloidogyne arenaria and Hirschmanniella oryzae. Five p lant ext racts(Cephalotaxus fortunei, Cephalotaxus sinensis, Paeonia suffrutccosa, Soph or a viciifolia and Derris elliptica) showed strong nematicidal activity against B ursaphelenchus xylophilus; 3 plant extracts (Cephalotaxus fortunei, Paeonia suf frutccosa, Sophora viciifolia) also showed strong nematicidal activity agains t M. arenaria and H.oryzae. While 4 plant extracts (Sargentodoxus argota enia, Mang lietia patungensis, Liriope spicata, and Liriodendron chinese) demonstrated no nematicidal activity against B. xylophilus and M. arenaria.%测定了中国湖北、陕西及广东省的10科14种植物抽提物对几种植物病原线虫的杀线活性,结果表明:对松材线虫,毛鱼藤(Derris elliptica)根有极强杀线活性,三尖杉( Cephalotaxus fortunei)茎叶、粗榧(Cephalotaxus sinensis)叶、狼牙刺( Sophora vi ciifolia)种子、紫斑牡丹(Paeonia suffrutccosa)茎有强杀线活性,神农香菊( Dendra nthema indicum)全株有中等杀线活性,瓜叶乌头(Aconitum hemsleyanum)全株、香果树(Emmenopterys henryi)叶、东方荚果蕨(Matteuccia orientalis)茎叶、大叶醉鱼草( Buddleja davidii)叶均无杀线活性;对花生根结线虫及水稻潜根线虫,三尖杉茎叶、狼牙刺种子、紫斑牡丹茎有极强杀线活性,神农香菊全株有中等杀线活性;大血藤(Sargento do xus argotaenia)茎、巴东木莲(Manglietia patungensis)叶、土麦冬(Liriop e spicat a)全株及鹅掌揪(Liriodendron chinese)叶对松材线虫、花生根结线虫均无杀线活性。

  2. Scientific Opinion on a composting method proposed by Portugal as a heat treatment to eliminate pine wood nematode from the bark of pine trees

    DEFF Research Database (Denmark)

    Baker, R.; Candresse, T.; Dormannsné Simon, E.

    2010-01-01

    Following a request from the European Commission, the Panel on Plant Health was asked to deliver a scientific opinion on the appropriateness of a composting method proposed by Portugal as a heat treatment to eliminate pine wood nematode (PWN), Bursaphelenchus xylophilus (Steiner and Buhrer) Nickl...

  3. Characterization of the Pinus massoniana transcriptional response to Bursaphelenchus xylophilus infection using suppression subtractive hybridization.

    Science.gov (United States)

    Xu, Liang; Liu, Zhen-Yu; Zhang, Kai; Lu, Quan; Liang, Jun; Zhang, Xing-Yao

    2013-05-28

    Pine wilt disease (PWD) caused by pine wood nematode (PWN), Bursaphelenchus xylophilus, is the most destructive diseases of pine and poses a threat of serious economic losses worldwide. Although several of the mechanisms involved in disease progression have been discovered, the molecular response of Pinus massoniana to PWN infection has not been explored. We constructed four subtractive suppression hybridization cDNA libraries by taking time-course samples from PWN-inoculated Masson pine trees. One-hundred forty-four significantly differentially expressed sequence tags (ESTs) were identified, and 124 high-quality sequences with transcriptional features were selected for gene ontology (GO) and individual gene analyses. There were marked differences in the types of transcripts, as well as in the timing and levels of transcript expression in the pine trees following PWN inoculation. Genes involved in signal transduction, transcription and translation and secondary metabolism were highly expressed after 24 h and 72 h, while stress response genes were highly expressed only after 72 h. Certain transcripts responding to PWN infection were discriminative; pathogenesis and cell wall-related genes were more abundant, while detoxification or redox process-related genes were less abundant. This study provides new insights into the molecular mechanisms that control the biochemical and physiological responses of pine trees to PWN infection, particularly during the initial stage of infection.

  4. Characterization of the Pinus massoniana Transcriptional Response to Bursaphelenchus xylophilus Infection Using Suppression Subtractive Hybridization

    Directory of Open Access Journals (Sweden)

    Xing-Yao Zhang

    2013-05-01

    Full Text Available Pine wilt disease (PWD caused by pine wood nematode (PWN, Bursaphelenchus xylophilus, is the most destructive diseases of pine and poses a threat of serious economic losses worldwide. Although several of the mechanisms involved in disease progression have been discovered, the molecular response of Pinus massoniana to PWN infection has not been explored. We constructed four subtractive suppression hybridization cDNA libraries by taking time-course samples from PWN-inoculated Masson pine trees. One-hundred forty-four significantly differentially expressed sequence tags (ESTs were identified, and 124 high-quality sequences with transcriptional features were selected for gene ontology (GO and individual gene analyses. There were marked differences in the types of transcripts, as well as in the timing and levels of transcript expression in the pine trees following PWN inoculation. Genes involved in signal transduction, transcription and translation and secondary metabolism were highly expressed after 24 h and 72 h, while stress response genes were highly expressed only after 72 h. Certain transcripts responding to PWN infection were discriminative; pathogenesis and cell wall-related genes were more abundant, while detoxification or redox process-related genes were less abundant. This study provides new insights into the molecular mechanisms that control the biochemical and physiological responses of pine trees to PWN infection, particularly during the initial stage of infection.

  5. Ascarosides coordinate the dispersal of a plant-parasitic nematode with the metamorphosis of its vector beetle

    Science.gov (United States)

    Zhao, Lilin; Zhang, Xinxing; Wei, Yanan; Zhou, Jiao; Zhang, Wei; Qin, Peijun; Chinta, Satya; Kong, Xiangbo; Liu, Yunpeng; Yu, Haiying; Hu, Songnian; Zou, Zhen; Butcher, Rebecca A.; Sun, Jianghua

    2016-01-01

    Insect vectors are required for the transmission of many species of parasitic nematodes, but the mechanisms by which the vectors and nematodes coordinate their life cycles are poorly understood. Here, we report that ascarosides, an evolutionarily conserved family of nematode pheromones, are produced not only by a plant-parasitic nematode, but also by its vector beetle. The pinewood nematode and its vector beetle cause pine wilt disease, which threatens forest ecosystems world-wide. Ascarosides secreted by the dispersal third-stage nematode LIII larvae promote beetle pupation by inducing ecdysone production in the beetle and up-regulating ecdysone-dependent gene expression. Once the beetle develops into the adult stage, it secretes ascarosides that attract the dispersal fourth-stage nematode LIV larvae, potentially facilitating their movement into the beetle trachea for transport to the next pine tree. These results demonstrate that ascarosides play a key role in the survival and spread of pine wilt disease. PMID:27477780

  6. Pine wilt disease in Yunnan, China: Evidence of non-local pine sawyer Monochamus alternatus (Coloptera: Cerambycidae) populations revealed by mitochondrial DNA

    Science.gov (United States)

    Da-Ying Fu; Shao-Ji Hu; Hui Ye; Robert A. Haack; Ping-Yang. Zhou

    2010-01-01

    Monochamus alternatus (Hope) specimens were collected from nine geographical populations in China,where the pinewood nematode Bursaphelenchus xylophilus (Steiner et Buhrer) was present. There were seven populations in southwestern China in Yunnan Province (Ruili,Wanding, Lianghe, Pu'er, Huaning, Stone Forest and Yongsheng),...

  7. Bursaphelenchus xylophilus is killed by homologues of 2-(1-undecyloxy)-1-ethanol

    Science.gov (United States)

    Kim, Junheon; Lee, Sang-Myeong; Park, Chung Gyoo

    2016-07-01

    2-(1-Undecyloxy)-1-ethanol, monochamol, is a male-produced aggregation pheromone of the Monochamus species, which are efficient vectors of the pine wood nematode (PWN), Bursaphelenchus xylophilus, which cause devastating damage to pines worldwide. The nematicidal activity of synthetic monochamol and its homologues (ROEtOH: R = C7-C13) were investigated to find potential alternatives to the currently used PWN control agents abamectin and emamectin. Compounds with C7-C13 chain length alkyl groups exhibited 100% nematicidal activity at a concentration of 1000 mg/L. At a concentration of 100 mg/L, 2-(1-nonyloxy)-1-ethanol (C9OEtOH), 2-(1-decyloxy)-1-ethanol (C10OEtOH), 2-(1-undecyloxy)-1-ethanol (C11OEtOH), and 2-(1-dodecyloxy)-1-ethanol (C12OEtOH) showed 100% nematicidal activity, but the others showed weaker activities. C11OEtOH showed similar nematicidal activity to abamectin in terms of LD90 values, which were 13.30 and 12.53 mg/L, respectively. However, C9OEtOH, C10OEtOH, and C12OEtOH (LC90 values: 53.63, 38.18, and 46.68 mg/L, respectively) were less effective than C11OEtOH and abamectin. These results indicate that monochamol could be an effective alternative agent against PWN. The relationship of insecticidal and nematicidal activity to different carbon chain lengths in compounds is discussed.

  8. Incidence of the pine wood nematode in green coniferous sawn wood in Oregon and California. Forest Service research note

    Energy Technology Data Exchange (ETDEWEB)

    Dwinell, L.D.

    1993-05-01

    Samples of green sawn Douglas-fir, redwood, ponderosa pine, and white fir were collected in August and September 1992 from seven mills in Oregon and California, and assayed for the pine wood nematode, Bursaphelenchus xylophilus. The mills produced about 108 million board feet during the survey period. The pine wood nematode was not found in any of the 424 samples of Douglas-fir, the 192 of redwood, or the 3 of white fir. The nematode was recovered from 8 of 105 samples of green ponderosa pine lumber from a mill in Oregon. These eight samples contained an average of 54 pine wood nematodes per gram of dry weight. This is the first report of the pine wood nematode in Oregon.

  9. High infectivity of an endoparasitic fungus strain, Esteya vermicola, against nematodes.

    Science.gov (United States)

    Wang, Chun Yan; Fang, Zhe Ming; Sun, Bai Shen; Gu, Li Juan; Zhang, Ke Qin; Sung, Chang-Keun

    2008-08-01

    Esteya vermicola, as the first recorded endoparasitic fungus of pinewood nematodes, exhibits great potential as a biological agent against nematodes. However, only two strains of this species have been described so far. In this study, we identified a novel endoparasitic fungal strain, CNU 120806, isolated from infected nematodes in forest soil samples during a survey of nematophagous fungi in Korea. This strain showed similar morphological characteristics and infection mode with the two previously described strains of E. vermicola. All strains are characterized by the ability to produce two types of conidiogenous cells and conidia, and to parasitize nematodes with lunate adhesive conidia. Moreover, the CNU 120806 strain showed 100% identity with E. vermicola CBS 115803 when their partial sequences of 28S rRNA gene were compared. Molecular phylogenetic analysis further identified CNU 120806 as a strain of E. vermicola, by clustering CNU 120806 and E. vermicola CBS 115803 into a single subclade. Culture medium influenced the proportion of dimorphic CNU 120806 conidia, and further changed the adhesive and mortality rates of nematodes. The CNU 120806 strain exhibits high infection activity against nematodes on nutrient-rich PDA medium. Almost all tested nematodes were killed within 8 approximately 10 days after inoculation. This study provides justification for further research of E. vermicola, and the application and formulation of this fungus as a bio-control agent against nematodes.

  10. Accumulation of eosinophils and T-lymphocytes in the lungs after exposure to pinewood dust.

    Science.gov (United States)

    Gripenbäck, S; Lundgren, L; Eklund, A; Lidén, C; Skare, L; Tornling, G; Grunewald, J

    2005-01-01

    Exposure to wood dust within the woodworking industry has been shown to cause a variety of respiratory disorders. The aim of this study was to investigate the cellular effects in bronchoalveolar lavage (BAL) fluid and peripheral blood from healthy individuals exposed to pinewood dust. Eleven healthy volunteers were exposed to pinewood dust for 1 h in a whole-body exposure chamber. BAL fluid and blood cells were differentially counted and the expression of activation, adhesion and subset markers on alveolar macrophages and T-lymphocytes was determined 2-6 weeks before and 20 h after the exposure. Following pinewood dust exposure, the total BAL fluid cell concentration increased from 81.4 (64.1-97.5) x 10(6) cells x L(-1) (median (interquartile range)) to 195.3 (154.6-341.2) x 10(6) cells x L(-1). The BAL fluid T-lymphocyte concentration increased from 3.8% (3.5-6.5%) to 7.6% (4.9-11.2%), and BAL fluid eosinophil concentration from 0.0% (0.0-0.2%) to 1.8% (0.6-3.5%). Inhalation of pinewood dust leads to the recruitment of inflammatory cells to the airways of healthy individuals. The increase in numbers of eosinophils, T-lymphocytes and mast cells, i.e. cells of crucial importance to airway inflammation, in the lungs may be related to the increased risk of developing respiratory disorders among woodworkers.

  11. Effect of stand structure on models for volume and aboveground biomass assessment (Castelfusano pinewood, Roma

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available The main purpose of this research was to analyse the effects of stand structure on biomass allocation and on the accurancy of estimation models for volume and aboveground biomass of Italian stone pine (Pinus pinea L.. Although the species is widely distributed on Mediterranean coasts, few studies on forest biomass estimation have focused on pinewoods. The research was carried out in the Castelfusano’s pinewood (Rome and concerned the two most common structural types: (a 50 years-old pinewood originated by broadcast seeding; and (b 62 years-old pinewood originated by partial seeding alternating worked strips to firm strips. Some 83 sample trees were selected for stem volume estimation and a subset of 32 trees used to quantify the total epigeous biomass, the wooden biomass compartment, including stem and big branches (diameter > 3 cm and the photosynthetic biomass, including thin branches (diameter < 3 cm and needles. Collected data were used to elaborate allometric relations for stem volume, total biomass and specific relations for both compartments, based on one (d2 or two (d2h indipendent variables, for both structural types. Furthermore, pinewood specific biomass expansion factors (BEF - indexes used to estimate carbon stocks starting from stem biomass data - were obtained. The achieved estimation models were subjected to both parallelism and coincidence tests, showing significant effects of stand structure on the accurancy of the allometric relations. The effects of stand structure and reliability of tree height curves on the accurancy of estimation models for volume and aboveground biomass and on biomass allocation in different compartments are analysed and discussed.

  12. 2000 years of human activity in Tuchola Pinewoods (northern Poland)

    Science.gov (United States)

    Obremska, Milena; Ott, Florian; Słowiński, Michał; Lutyńska, Monika; Błaszkiewicz, Mirosław; Brauer, Achim

    2014-05-01

    During the last two millennia human activity and their settlements together with varying climate conditions strongly influenced landscape scale changes. Especially within palaeoecological records these environmental responses are well expressed. However, a robust age control is needed for the evaluation and interpretation of biotic proxies.We present a record from the annually laminated (varved) sediments of Lake Czechowskie, located in northern Poland. The investigated record covers the past 2000 years and demonstrates the continuous vegetation history and human activity in the Northern part of the Tuchola Pinewoods. The chronology was established by varve counting and confirmed by AMS 14C dating, 137Cs activity measurement and a tephra layer (Askja 1875). We used high-resolution biotic (pollen, green algae and diatom analysis) sedimentological (varve and sublayer thickness variations) and geochemical (µ-XRF data) proxies to reconstruct the environmental changes within a time of increasing human activity and fluctuating climatic conditions. Based on different spatial sampling and measuring increments the temporal resolution varies between subseasonal (µ-XRF), annual (varves) up to five-varveresolution (biotic proxies) making it possible to trace even short lasting local and regional changes. Our results display visible human pressure in this area between 50- 350 yr. AD (Roman Period) exerted by tribes related to the Wielbark Culture. The development of persisting settlements and agriculture took place at expense of surrounding hornbeam forests. An intensification of lake productivity (expressed as an increase of varve thickness) started after 250 AD. If this lake ecosystem response relates to an intensified agriculture (and a possible transport of nutrients from neighboring rural lands) or to a climate shift will be further discussed. The rapid decline of human indicators about 350 years AD at the transition to the migration period might be related to cooler

  13. Lipid accumulation from pinewood pyrolysates by Rhodosporidium diobovatum and Chlorella vulgaris for biodiesel production.

    Science.gov (United States)

    Luque, Luis; Orr, Valerie C A; Chen, Sean; Westerhof, Roel; Oudenhoven, Stijn; Rossum, Guus van; Kersten, Sascha; Berruti, Franco; Rehmann, Lars

    2016-08-01

    This study evaluated the suitability of pinewood pyrolysates as a carbon source for lipid production and cultivation of the oleaginous yeast Rhodosporidium diobovatum and the microalgae Chlorella vulgaris. Thermal decomposition of pinewood and fractional condensation were used to obtain an oil rich in levoglucosan which was upgraded to glucose by acid hydrolysis. Blending of pyrolytic sugars with pure glucose in both nitrogen rich and nitrogen limited conditions was studied for R. diobovatum, and under nitrogen limited conditions for C. vulgaris. Glucose consumption rate decreased with increasing proportions of pyrolytic sugars increasing cultivation time. While R. diobovatum was capable of growth in 100% (v/v) pyrolytic sugars, C. vulgaris growth declined rapidly in blends greater than 20% (v/v) until no growth was detected in blends >40%. Finally, the effects of pyrolysis sugars on lipid composition was evaluated and biodiesel fuel properties were estimated based on the lipid profiles.

  14. Proposal for the establishment of a “silvo-museum” in the Ravenna historical pinewoods

    Directory of Open Access Journals (Sweden)

    Andreatta G

    2010-12-01

    Full Text Available In the last decade, Ravenna historical pinewoods, whose history is older than eight centuries, have undergone deep changes in the structure and specific composition, dramatically altering the original aspect of the biocoenosis, and leading more and more to a mixed and multi-layered forest formation. To conserve and maintain the forest, the landscapes, and the historical and cultural values characterizing the whole territory over centuries, we suggest to establish a “silvo-museum” (a “forest museum” in the Ravenna historical pinewoods. Possible ways and activities aimed at the achievement of this goal are discussed. Moreover, divulgation and environmental education initiatives, along with suitable scientific and technical activities, are requested to bring to proper importance the silvo-museum.

  15. Identification and Characterization of a Bursaphelenchus xylophilus (Aphelenchida: Aphelenchoididae Thermotolerance-Related Gene: Bx-HSP90

    Directory of Open Access Journals (Sweden)

    Danlei Li

    2012-07-01

    Full Text Available Temperatures directly influence the distribution and intensity of pine wilt disease caused by the pine wood nematode, Bursaphelenchus xylophilus. To date, however, little is known about the causation and mechanism of this influence. The molecular chaperone HSP90 is a key component that contributes to survival in the abiotic stress response. In this study, we investigated the relationship between the survival of B. xylophilus and the functionality of the HSP90 gene. Bx-HSP90 was cloned from a suppression subtractive hybridization library. In situ mRNA hybridization showed that Bx-HSP90 was constitutively expressed in response to all of the temperatures tested, and RT-PCR indicated that all of the temperatures could induce Bx-HSP90 transcription, with the highest transcript level detected at 30 °C. The suppression of the Bx-HSP90 transcript by RNA interference led to a 25% reduction in the number of nematodes at 30 °C after 44 h. Sharp declines in the survival of the RNAi-treated nematodes were observed after 8 days at 25 °C, 48 h at 30 °C and 24 h at 35 °C. Both heat shock and the knockdown of Bx-HSP90 hindered the growth of the B. xylophilus populations. The results indicate that Bx-HSP90 is essential for the survival of B. xylophilus, confirming the thermoregulatory function of the gene, and delineate the timeframe and temperature range within which the gene function occurs.

  16. Root-knot nematodes

    NARCIS (Netherlands)

    Karssen, G.; Wesemael, W.M.L.; Moens, M.

    2013-01-01

    Plant-parasitic nematodes devastate crops worldwide, in turn impacting international trade, social and economic development. Effective control of nematodes is essential for crop protection, and requires an understanding of nematode biology, taxonomy, population dynamics and sampling methods.

  17. Root-knot nematodes

    NARCIS (Netherlands)

    Karssen, G.; Wesemael, W.M.L.; Moens, M.

    2013-01-01

    Plant-parasitic nematodes devastate crops worldwide, in turn impacting international trade, social and economic development. Effective control of nematodes is essential for crop protection, and requires an understanding of nematode biology, taxonomy, population dynamics and sampling methods. Providi

  18. Niche of insect borers within Pinus massoniana infected by pine wood nematode

    Institute of Scientific and Technical Information of China (English)

    SONG Jiying; LUO Youqing; SHI Juan; YAN Xiaosu; CHEN Weiping; JIANG Ping

    2006-01-01

    In November 2003 and June 2004,the insect borers and their spatial distribution within Pinus massoniana were investigated in Zhoushan City,in East China's Zhejiang Province,where pine wood nematode (Bursaphelenchus xylophilus) are typically found.The niche width,proportional similarity of niche and the niche overlap of dominant species of dying trees were computed.Results show that five insect species infect and damage Pinus massoniana,which had been infected by pine wood nematodes,among which four are wood boring beetles and one termite.Species within host trees vary from winter to summer and all the species have their own niche width,proportional similarity of niche and the niche overlap.They can achieve competitive equilibrium and coexistence according to their biological characteristics and life habits.

  19. Characterisation of palm empty fruit bunch (PEFB) and pinewood bio-oils and kinetics of their thermal degradation.

    Science.gov (United States)

    Pimenidou, P; Dupont, V

    2012-04-01

    Ultimate and proximate analyses and thermal degradation of bio-oils from pinewood and palm empty fruit bunches (PEFB) were carried out to evaluate the oils' potential for production of fuels for transport, heat and power generation, and of hydrogen via the calculation of performance indicators. The pinewood and PEFB oils indicated good theoretical hydrogen yields of 13.7 and 15.9 wt.% via steam reforming, but their hydrogen to carbon effective ratios were close to zero, and their propensity for fouling and slagging heat exchanger surfaces via combustion was high. Both oils exhibited two phases during mass loss under nitrogen flow at heating rates of 3-9 Kmin(-1), but the kinetics of their thermal degradation from TGA-FTIR analysis indicated different degradation mechanisms that were well reproduced by a nth order reaction model for pinewood and Jander's 3D-diffusion model for PEFB. These findings lead to recommendations on pretreatments prior to the oils' utilisation.

  20. Biodiversity of entomopathogenic nematodes in Italy.

    Science.gov (United States)

    Tarasco, E; Clausi, M; Rappazzo, G; Panzavolta, T; Curto, G; Sorino, R; Oreste, M; Longo, A; Leone, D; Tiberi, R; Vinciguerra, M T; Triggiani, O

    2015-05-01

    An investigation was carried out on the distribution and biodiversity of steinernematid and heterorhabdtid entomopathogenic nematodes (EPN) in nine regions of Italy in the period 1990-2010. More than 2000 samples were collected from 580 localities and 133 of them yielded EPN specimens. A mapping of EPN distribution in Italy showed 133 indigenous EPN strains belonging to 12 species: 43 isolates of Heterorhabditis bacteriophora, 1 of H. downesi, 1 of H. megidis, 51 of Steinernema feltiae, 12 of S. affine, 4 of S. kraussei, 8 of S. apuliae, 5 of S. ichnusae, 3 of S. carpocapsae, 1 of S. vulcanicum, 3 of Steinernema 'isolate S.sp.MY7' of 'S. intermedium group' and 1 of S. arenarium. Steinernematids are more widespread than heterorhabditids and S. feltiae and H. bacteriophora are the most commonly encountered species. Sampling sites were grouped into 11 habitats: uncultivated land, orchard, field, sea coast, pinewood, broadleaf wood, grasslands, river and lake borders, caves, salt pan and moist zones; the soil texture of each site was defined and the preferences of habitat and soil texture of each species was assessed. Except for the two dominant species, S. feltiae and H. bacteriophora, EPN occurrence tends to be correlated with a specific vegetation habitat. Steinernema kraussei, H. downesi and H. megidis were collected only in Sicily and three of the species recently described - S. apuliae, S. ichnusae and S. vulcanicum - are known only from Italy and seem to be endemic.

  1. Sequencing and Analysis of the Pseudomonas fluorescens GcM5-1A Genome: A Pathogen Living in the Surface Coat of Bursaphelenchus xylophilus.

    Directory of Open Access Journals (Sweden)

    Kai Feng

    Full Text Available It is known that several bacteria are adherent to the surface coat of pine wood nematode (Bursaphelenchus xylophilus, but their function and role in the pathogenesis of pine wilt disease remains debatable. The Pseudomonas fluorescens GcM5-1A is a bacterium isolated from the surface coat of pine wood nematodes. In previous studies, GcM5-1A was evident in connection with the pathogenicity of pine wilt disease. In this study, we report the de novo sequencing of the GcM5-1A genome. A 600-Mb collection of high-quality reads was obtained and assembled into sequence contigs spanning a 6.01-Mb length. Sequence annotation predicted 5,413 open reading frames, of which 2,988 were homologous to genes in the other four sequenced P. fluorescens isolates (SBW25, WH6, Pf0-1 and Pf-5 and 1,137 were unique to GcM5-1A. Phylogenetic studies and genome comparison revealed that GcM5-1A is more closely related to SBW25 and WH6 isolates than to Pf0-1 and Pf-5 isolates. Towards study of pathogenesis, we identified 79 candidate virulence factors in the genome of GcM5-1A, including the Alg, Fl, Waa gene families, and genes coding the major pathogenic protein fliC. In addition, genes for a complete T3SS system were identified in the genome of GcM5-1A. Such systems have proved to play a critical role in subverting and colonizing the host organisms of many gram-negative pathogenic bacteria. Although the functions of the candidate virulence factors need yet to be deciphered experimentally, the availability of this genome provides a basic platform to obtain informative clues to be addressed in future studies by the pine wilt disease research community.

  2. Sequencing and Analysis of the Pseudomonas fluorescens GcM5-1A Genome: A Pathogen Living in the Surface Coat of Bursaphelenchus xylophilus.

    Science.gov (United States)

    Feng, Kai; Li, Ronggui; Chen, Yingnan; Zhao, Boguang; Yin, Tongming

    2015-01-01

    It is known that several bacteria are adherent to the surface coat of pine wood nematode (Bursaphelenchus xylophilus), but their function and role in the pathogenesis of pine wilt disease remains debatable. The Pseudomonas fluorescens GcM5-1A is a bacterium isolated from the surface coat of pine wood nematodes. In previous studies, GcM5-1A was evident in connection with the pathogenicity of pine wilt disease. In this study, we report the de novo sequencing of the GcM5-1A genome. A 600-Mb collection of high-quality reads was obtained and assembled into sequence contigs spanning a 6.01-Mb length. Sequence annotation predicted 5,413 open reading frames, of which 2,988 were homologous to genes in the other four sequenced P. fluorescens isolates (SBW25, WH6, Pf0-1 and Pf-5) and 1,137 were unique to GcM5-1A. Phylogenetic studies and genome comparison revealed that GcM5-1A is more closely related to SBW25 and WH6 isolates than to Pf0-1 and Pf-5 isolates. Towards study of pathogenesis, we identified 79 candidate virulence factors in the genome of GcM5-1A, including the Alg, Fl, Waa gene families, and genes coding the major pathogenic protein fliC. In addition, genes for a complete T3SS system were identified in the genome of GcM5-1A. Such systems have proved to play a critical role in subverting and colonizing the host organisms of many gram-negative pathogenic bacteria. Although the functions of the candidate virulence factors need yet to be deciphered experimentally, the availability of this genome provides a basic platform to obtain informative clues to be addressed in future studies by the pine wilt disease research community.

  3. Changes of reducing sugar and mineral nutrient elements in Pinus thunbergii and Pinus massoniana at different stage naturally infected by Bursaphelenchus xylophilus%松材线虫自然侵染后松树还原糖与矿质营养元素的变化

    Institute of Scientific and Technical Information of China (English)

    黄秀凤; 张慧; 徐华潮

    2013-01-01

    We have analyzed the contents of reducing sugar and mineral nutrient nutrients in Pinus thunbergii and Pinus massoniana at different Pine wilt disease stage naturally infected by the pine wood nematode Bursaphelenchus xylophilus in P. thunbergii and P. massoniana at different Pine Wilt disease stage naturally infected by the pine wood nematode B. xylophilus conifers. With disease progression, the contents of reducing sugar and nitrogen element decreased in both lodgepole and red pines. The changes in other minerals were inconsistent between the two types of pines. These results indicated that the structural damage caused by nematode infection significantly compromised metabolism, and affected the absorption, movement and utilization of different nutrients in the host plants.%实验测定了马尾松Pinus massoniana、黑松Pinus thunbergii在松材线虫Bursaphelenchus xylophilus自然侵染状态下针叶内还原糖及矿质营养元素的变化趋势.结果表明,两种松树随病程发展针叶内还原糖及N元素含量均逐渐降低;其余矿质元素含量变化不一.表明由于松材线虫的侵入,破坏了植物的组织结构,影响了寄主的新陈代谢和物质循环,继而影响到对各种元素的吸收、转移及利用.

  4. Diagnostic technique of pine wood nematode disease based on THz spectrum

    Science.gov (United States)

    Liu, Yunfei; Tan, Jiajin; Jiang, Liang; Shi, Shengcai; Jin, Biaobing; Ma, Jinlong

    2008-12-01

    Pine wood nematode disease, namely pine wilt disease, is caused by the invasion of Bursaphelenchus xylophilus (Bx) into pines. Once susceptible pines are infected by the nematode, the disease develops rapidly, the infected pines cease to exude oleoresin and die quickly. Hence it is called pine cancer. Given the fact that there are still no good methods in diagnosing the disease, here we propose to study the spectroscopic characteristics of pine wood nematode and diseased pine wood in the THz regime in order to look for a rapid spectroscopic discrimination method for the disease. Firstly, we measure the transmittances of a Bx sample, a B. mucronatus (Bm) sample, a healthy Pinus massoniana wood sample and a diseased P. massoniana wood sample by a superconducting heterodyne mixer at 500 GHz. And their characteristics are compared. Secondly, we measure the transmission characteristics of a Bx sample and a Bm sample by terahertz time domain spectroscopy (THz-TDS). The measured time domain spectrums and corresponding frequency domain spectrums are compared to distinguish them from their absorption characteristics. Thirdly, we measure the transmission characteristics of a healthy P. massoniana wood sample and a diseased P. massoniana wood sample by THz TDS and compare their difference in THz absorption spectrum and diffraction dispersive spectrum to confirm the effect of Bx on P. massoniana by the absorption coefficient and refractive index. Some discussions are given for future development of the diagnostic technique of pine wood nematode disease based on THz spectrum.

  5. Nematode diversity in agroecosystems

    NARCIS (Netherlands)

    Yeates, G.W.; Bongers, T.

    1999-01-01

    The diversity of nematode faunae in agroecosystems and their relationships to soil processes suggests that they are potential bioindicators. However, the effects of plants, soil types and nematode biogeography mean a 'functional group' may be a better indicator than particular nematodes.

  6. Rapid Identification of Bursaphelenchus xylophilus and Determination Epidemic Areas by Comparative Morphology and Polymerase Chain Reaction Technology%应用比较形态学与PCR技术快速鉴定松材线虫及确立疫区

    Institute of Scientific and Technical Information of China (English)

    叶燕华; 李迅东; 张志荣; 卓侃; 廖金铃; 陈沐荣; 秦长生

    2014-01-01

    Pine wood nematode disease,caused by Bursaphelenchus xylophilus,is a destructive disease to pine.In this paper,The sample of the dead tree of suspected pine wilt disease,collected in different epidemic are-as of Guangdong province from 2004 to 2005 were studied.The results showed that application the technologies of comparative morphology and polymerase chain reaction (PCR)could rapid discriminate B.xylophilus,and reliably determinate epidemic areas.%松材线虫病(Bursaphelenchus xylophilus)是为害松树的一种毁灭性病害。应用比较形态学,并辅助以PCR分子生物学检测技术,对广东省2004-2005年间松材线虫病监测普查过程中采集的疑似样本进行对比研究,结果表明该技术可以快速、准确鉴定松材线虫并确立疫区。

  7. Effects of Insect Ecdysone and Juvenile Hormone on Reproduction of Bursaphelenchus xylophilus%昆虫蜕皮激素和保幼激素对松材线虫繁殖的影响

    Institute of Scientific and Technical Information of China (English)

    林峰; 袁冬菊; 赵博光; 王华光

    2014-01-01

    研究了外源昆虫蜕皮激素和保幼激素对松材线虫( Bursaphelenchus xylophilus)繁殖的影响。用10-6 g/mL到10-9 g/mL的7个连续几何级数浓度的保幼激素或蜕皮激素处理线虫。保幼激素处理6 d及以后的松材线虫繁殖数量显著高于空白对照和仅提供灰葡萄孢为营养的对照( P<0.05)。在观察时间内,保幼激素浓度以5×10-7 g/mL为线虫繁殖量的最高峰值,其线虫繁殖数量显著高于其他浓度( P<0.05)。蜕皮激素对松材线虫的繁殖同样具有明显的促进作用,激素处理6 d及以后的松材线虫繁殖数量显著高于两组对照( P<0.05)。在观察时间内,蜕皮激素浓度以5×10-7 g/mL为线虫繁殖量的最高峰值,且明显高于其他浓度的处理(P<0.05)。此外还发现保幼激素和蜕皮激素在浓度为5×10-9 g/mL处存在线虫繁殖的次高峰。%The effects of the insect 20-hydroxyecdysone and juvenile hormoneⅢ on reproduction of pine wood nematode,Bursaphelenchus xylophilus,were investigated.The nematodes were treated with 7 continuous geometric concentration series of 20-hydroxyecdysone or juvenile hormone Ⅲ.The numbers of the nematodes treated with 20-hydroxyecdysone or juvenile hormone Ⅲfrom the 6th day to the 9th were significantly higher than those of the blank control and the control treated with only the nematode food ,Botrytis cinerea ( P<0.05) . During the observing period the peak of the reproduction was at 5 ×10-7 g/mL of the ecdysone and the peak value was significantly higher than those in the other concentrations .During the observing period the peak of the number of the nematodes was at 5×10-7 g/mL of the two hormones and it was significantly higher than those in the other concentrations of the hormones .The second peak of the nematode number was also found at 5 ×10-9 g/mL in both the ecdysone and the juvenile hormone .

  8. 松材线虫两种实用分子检测技术%Two kinds of appliedmolecular skills to detect Bursaphelenchus xylophilus

    Institute of Scientific and Technical Information of China (English)

    陈凤毛; 叶建仁; 吴小芹; 谈家金; 黄麟

    2011-01-01

    In order to determine the reliability of two methods, SCAR marker and real-time PCR, developed for detecting pine wood nematode, seven pine wood isolates and three identified nematode strains ( Bursaphelenchus xflophilus, B. mucronatus and Aphelenchoicles macronucleatus ) were assayed with the two methods. The traditional method of morphological identification was also used to determine the seven isolates samples. Results showed that 1 ) with the method of SCAR marker, isolates 2, 3, 4 and 7 showed a common specific electrophoretic band of 860 bp, as did by pine wood nematode B. xylophilus, whereas isolates 1, 5 and 6, and B. mucronatus and Aphelenchoides macronucleatus did not produce the specific band. That suggests that isolates 2, 3, 4 and 7 contained B. xylophilus, while isolates 1, 5 and 6 did not. 2) With the method of real-time PCR identification, fluorescent signal was detected from samples prepared from isolate 2, 3, 4, 7 and strain B. xylophilus, on the contrary, the rest isolates showed no signals and cycle threshold ( Ct values). 3) With morphological identification, it was revealed that isolate 2, 4 and 7 contained B. xylophilus while isolate 3 contained B. xylophilus as well as other nematodes. However, isolate 1, 5 and 6 did not contain B. xylophilus. Therefore, the two molecular methods showed a consistent result with morphological identification. Moreover, the two methods are highly specific and time-saving. SCAR marker method costs two hours to perform, while real-time PCR method takes only one hour. Both techniques make it possible to determine rapidly existence of juvenilepine wood nematodes with a simple and easily readable result.%为检验已开发的SCAR标记与实时PCR两种分子检测方法鉴定松材线虫的可靠性,本文选用线虫未知种样品7个以及已知种样品3个为实验材料,采用上述两种分子检测方法进行检测,并且对7个线虫未知种样品进行形态鉴定。结果表明:1

  9. Distribution and reproduction of Bursaphelenchus xylophilus populations in wood and bark of western north american conifers

    OpenAIRE

    Forge, T.A.; Sutherland, J. R.

    1996-01-01

    La croissance de population de #Bursaphelenchus xylophilus$ a été étudiée dans le bois et l'écorce d'#Abies grandis$, #Pinus contorta$, #Pseudotsuga menziesii$, #Tsuga heterophylla$ et #Thuja plicata$. Le nématode a été inoculé dans des tronçons de tige (6 cm de diamètre et 25 cm de longueur) de chaque essence, puis mis en incubation dans des sacs de plastique, à la température ambiante (22 plus ou moins 4°C). Les populations de nématodes ont été échantillonnées séparément dans le bois et l'é...

  10. 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.

  11. The Nematode Caenorhabditis Elegans.

    Science.gov (United States)

    Kenyon, Cynthia

    1988-01-01

    Discusses advantages of nematode use for studying patterns of cell division, differentiation, and morphogenesis. Describes nematode development. Cites experimental approaches available for genetic studies. Reviews the topics of control of cell division and differentiation, the nervous system, and muscle assembly and function of the organism. (RT)

  12. Economic impact of NMMO pretreatment on ethanol and biogas production from pinewood.

    Science.gov (United States)

    Shafiei, Marzieh; Karimi, Keikhosro; Zilouei, Hamid; Taherzadeh, Mohammad J

    2014-01-01

    Processes for ethanol and biogas (scenario 1) and biomethane (scenario 2) production from pinewood improved by N-methylmorpholine-N-oxide (NMMO) pretreatment were developed and simulated by Aspen plus. These processes were compared with two processes using steam explosion instead of NMMO pretreatment ethanol (scenario 3) and biomethane (scenario 4) production, and the economies of all processes were evaluated by Aspen Process Economic Analyzer. Gasoline equivalent prices of the products including 25% value added tax (VAT) and selling and distribution expenses for scenarios 1 to 4 were, respectively, 1.40, 1.20, 1.24, and 1.04 €/l, which are lower than gasoline price. The profitability indexes for scenarios 1 to 4 were 1.14, 0.93, 1.16, and 0.96, respectively. Despite the lower manufacturing costs of biomethane, the profitability indexes of these processes were lower than those of the bioethanol processes, because of higher capital requirements. The results showed that taxing rule is an effective parameter on the economy of the biofuels. The gasoline equivalent prices of the biofuels were 15-37% lower than gasoline; however, 37% of the gasoline price contributes to energy and carbon dioxide tax which are not included in the prices of biofuels based on the Swedish taxation rules.

  13. Economic Impact of NMMO Pretreatment on Ethanol and Biogas Production from Pinewood

    Directory of Open Access Journals (Sweden)

    Marzieh Shafiei

    2014-01-01

    Full Text Available Processes for ethanol and biogas (scenario 1 and biomethane (scenario 2 production from pinewood improved by N-methylmorpholine-N-oxide (NMMO pretreatment were developed and simulated by Aspen plus. These processes were compared with two processes using steam explosion instead of NMMO pretreatment ethanol (scenario 3 and biomethane (scenario 4 production, and the economies of all processes were evaluated by Aspen Process Economic Analyzer. Gasoline equivalent prices of the products including 25% value added tax (VAT and selling and distribution expenses for scenarios 1 to 4 were, respectively, 1.40, 1.20, 1.24, and 1.04 €/l, which are lower than gasoline price. The profitability indexes for scenarios 1 to 4 were 1.14, 0.93, 1.16, and 0.96, respectively. Despite the lower manufacturing costs of biomethane, the profitability indexes of these processes were lower than those of the bioethanol processes, because of higher capital requirements. The results showed that taxing rule is an effective parameter on the economy of the biofuels. The gasoline equivalent prices of the biofuels were 15–37% lower than gasoline; however, 37% of the gasoline price contributes to energy and carbon dioxide tax which are not included in the prices of biofuels based on the Swedish taxation rules.

  14. Enhanced Ethanol and Biogas Production from Pinewood by NMMO Pretreatment and Detailed Biomass Analysis

    Science.gov (United States)

    Zilouei, Hamid; Taherzadeh, Mohammad J.

    2014-01-01

    N-Methyl morpholine-N-oxide (NMMO) is an environmentally friendly and commercially applied cellulose solvent that is suggested for pretreatment of lignocelluloses to improve biofuel productions. However, the underlying mechanisms of the improvements have been poorly understood yet. In an attempt to investigate the mechanisms, pinewood powder and chips were pretreated with 85% (w/w) NMMO at 120°C for 1–15 h. The pretreatment improved ethanol production yield from 7.2% (g/g) for the untreated wood powder to 68.1–86.1% (g/g) and from 1.7% (g/g) for the untreated wood chips to 12.6–51.2% (g/g) of theoretical yield. Similarly, the biogas yields of untreated wood chips and powder were improved from 21 and 66 (mL/g volatile solids) by 3.5–6.8- and 2.6–3.4-folds, respectively. SEM micrographs indicated major increase in the wood porosity by the pretreatment, which would confirm increase in the water swelling capacity as well as enzyme adsorption. The analysis of X-ray diffraction showed considerable reduction in the cellulose crystallinity by the pretreatment, while FTIR spectroscopy results indicated reduction of lignin on the wood surface by the pretreatment. PMID:25162014

  15. Economic Impact of NMMO Pretreatment on Ethanol and Biogas Production from Pinewood

    Science.gov (United States)

    Zilouei, Hamid; Taherzadeh, Mohammad J.

    2014-01-01

    Processes for ethanol and biogas (scenario 1) and biomethane (scenario 2) production from pinewood improved by N-methylmorpholine-N-oxide (NMMO) pretreatment were developed and simulated by Aspen plus. These processes were compared with two processes using steam explosion instead of NMMO pretreatment ethanol (scenario 3) and biomethane (scenario 4) production, and the economies of all processes were evaluated by Aspen Process Economic Analyzer. Gasoline equivalent prices of the products including 25% value added tax (VAT) and selling and distribution expenses for scenarios 1 to 4 were, respectively, 1.40, 1.20, 1.24, and 1.04 €/l, which are lower than gasoline price. The profitability indexes for scenarios 1 to 4 were 1.14, 0.93, 1.16, and 0.96, respectively. Despite the lower manufacturing costs of biomethane, the profitability indexes of these processes were lower than those of the bioethanol processes, because of higher capital requirements. The results showed that taxing rule is an effective parameter on the economy of the biofuels. The gasoline equivalent prices of the biofuels were 15–37% lower than gasoline; however, 37% of the gasoline price contributes to energy and carbon dioxide tax which are not included in the prices of biofuels based on the Swedish taxation rules. PMID:25276777

  16. First record of Bursaphelenchus rainulfi on pine trees from eastern China and its phylogenetic relationship with intro-genus species

    Institute of Scientific and Technical Information of China (English)

    JIANG Li-qin; LI Xu-qing; ZHENG Jing-wu

    2007-01-01

    Bursaphelenchus rainulfi isolated from dead pine trees in Zhejiang, China, is described and illustrated. It also provided some molecular characters of the Chinese population, including the PCR-RFLP and sequences of ITS region and D2-D3expansion region of the large subunit (LSU) rRNA gene. Both the morphological characters and ITS-RFLP patterns match with the original description. The phylogenetic trees based on the 13 sequences of D2-D3 expansion region of the LSU rRNA gene and ITS region of Bursaphelenchus species were constructed, respectively, with the results showing the similar clades. The phylogenetic relationship based on the molecular data is similar to that with morphological characters. This is the first report of the species on pine wood in eastern China.

  17. Traits of Masson Pine Affecting Attack of Pine Wood Nematode

    Institute of Scientific and Technical Information of China (English)

    Juan Shi; You-Qing Luo; Ji-Ying Song; Hai-Wei Wu; Lei Wang; Gary Z. Wang

    2007-01-01

    Masson pine characteristics were analyzed in five sample plots in Zhejiang Province, China.Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle (pine wood nematode, PWN) carried by Monochamus alternatus predominately attacked Masson pines in the lower diameter classes.Among the 10 tree characteristics examined, mean crown width, percentage of bole with crown, 5-year cumulative diameter growth, and resin amount showed significant variation between successfully attacked and unattacked trees.The attacked trees had a lower percentage of the bole covered with tree crown, lower crown width, lower radial growth in the last 5 years, and produced less induced resinosis than unattacked trees.Results allowed for effective ranking of the pine forest based on individual tree resistance to PWN.This Index of resistance should be considered throughout the development of an "Evaluation Criterion and Indicator System".The preceding ranking can be used to evaluate the resistance and resiliency of the pine forest ecosystem to PWN's invasion, which is similar to Pest Risk Analysis (PRA).

  18. 抗松材线虫病马尾松无性系种子园营建技术%Technique on the establishment of a clonal seed orchard in Pinus massoniana for resistance to Bursaphelenchus xylophilus

    Institute of Scientific and Technical Information of China (English)

    章健; 徐六一; 高景斌; 陈雪莲; 姜春武; 郝焰平

    2012-01-01

    Pine wood nematode( Bursaphelenchus xylophilus) disease is a destructive one for pines. It causes a serious damage and it is difficult to prevent. 324 excellent disease resistance trees have been selected from Masson' s pine ( Pinus mas-soniana) stand in epidemic area and non-epidemic area of Anhui province since 2001. With some provenances from Guangdong and Guangxi, the disease resistance of these clones had been tested by a way of grafting propagation and artificial inoculation of pine wood nematode. In 2011, 89 clones with high resistance were chosen from 68 families. Then they were used to establish 1.6 hm2 clonal seed orchard. Survival rate of each family was 90.9% -100% , and the average survival rate was 93. 6% .%松材线虫病是危害松属树种的毁灭性病害,危害严重、防治困难.安徽省从2001年开始从疫区和非疫区的马尾松林分中选择324株抗病优树以及部分广东、广西种源,通过嫁接繁殖和人工接种松材线虫的方法进行无性系抗病性测定.2011年利用筛选出的68个家系的89个高抗无性系营建了1.6 hm2抗松材线虫病马尾松无性系种子园.各家系成活率90.9%~100%,平均成活率93.6%.

  19. 抗松材线虫病赤松组培苗的抗病性测定1)%Resistance Determination of Wilt-resistant Pinus densiflora Tissue Culture Seedling to Bursaphelenchus xylophilus

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    An experiment was conducted to determine the resistance of wilt-resistant Pinus densiflora to Bursaphelenchus xylophi-lus from Japan.Six months old tissue culture seedlings of Pinus densiflora were inoculated with middle virulence aseptic pine wood nematode under aseptic conditions.There are obvious differences of resistance in Pinus densiflora families.No.1 and 10 families have better resistant effects, followed by No.2, 13, 19, 22 and 23 families.The resistance difference of clones mainly originates from the families.Meanwhile, the relationship between pine wood nematode breeding rates and disease incidence was discussed.There is a low correlation between the disease incidence of wilt-resistant Pinus densiflora and pine wood nematode propagation coefficient.In addition, the susceptible tissue culture seedlings were isolated.The pine wood nematode remains aseptic.%  为了评价从日本引进的抗性赤松对松材线虫的抗病性,在无菌条件下,用中强毒力无菌松材线虫对6个月生的无菌赤松组培苗进行接种。结果表明:抗性赤松不同家系间抗病性差异明显,1号和10号家系抗病性表现较好,2、13、19、22和23号家系抗病性表现次之,3、14和16号家系未表现出抗病性;抗性赤松不同无性系间的抗病性存在极显著差异,无性系间的抗病性差异主要来源于家系间的抗病性差异。发病率与松材线虫繁殖倍数相关性极低。从发病组培苗上分离的松材线虫仍然无菌。

  20. Toward 959 nematode genomes

    National Research Council Canada - National Science Library

    Kumar, Sujai; Koutsovoulos, Georgios; Kaur, Gaganjot; Blaxter, Mark

    2012-01-01

    The sequencing of the complete genome of the nematode Caenorhabditis elegans was a landmark achievement and ushered in a new era of whole-organism, systems analyses of the biology of this powerful model organism...

  1. Advance of entomopathogenic nematodes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper summarized the history and present condition of studying and utilizing entomopathogenic nematodes at home and abroad, expounded its taxonomy, life cycle and the mechanism with symbiotic bacteria killing host insect. Taxonomy, mycelial form, pathogenic function and anti-bacteria function of symbiotic bacteria were introduced. Production and utilization of entomopathogenic nematodes, the characteristic genetic improvement by use of biological engineering technology, as well as the existing problem and applying foreground were also discussed.

  2. 木质包装热处理国际标准对松材线虫有效性的试验研究%Confirmatory test on the validity of heat treatment of ISPM 15 to disinfestation of Bursaphelenchus xylophilus in wood packaging material

    Institute of Scientific and Technical Information of China (English)

    詹国平; 王新; 李丽; 王跃进; 杨赛军; 张瑞峰

    2009-01-01

    使用温度为65~85℃、相对湿度50%~90%的热空气,对不同规格和含水率的携带松材线虫(Bursaphelenchus xylophilus)的马尾松(Pinus massoniana)木板进行热处理验证试验,结果显示,当木材中心温度达到56℃并持续30min以上,10cm×10cm×10cm木块、5cm厚度木板以及高含水率10cm厚度木板中线虫死亡几率值达到9的要求,验证了国际植物检疫措施标准第15号所推荐的热处理技术指标对杀灭松材线虫的有效性.试验中也发现10cm厚度含水率低于30%木板的线虫死亡率达不到几率值9的要求,其原因可能是中心温度或持续时间没有达到该标准要求.%To validate heat treatment requirement of ISPM 15 to disinfestation of Pine wood nematode (Bursaphelenchus xylophilus) in wood packaging material, lumber and block made from Masson Pine with different moisture content (MC), which was naturally infested with Pine wood nematode and sawed to 3 kinds of size, was heat trea-ted under the hot air with the temperature rang of 65 ~ 85℃ and Relative Humidity of 50% ~ 90% to reach the core temperature of 56℃ and more than 30min duration. The results shows that the mortality of the nematodes in all woods except in 10 × 10 × 80cm lumber with MC below 30% meet the requirement of mortality of probit 9 un-der 95% confidence level, the possible reason for the exception was due to the core temperature in wood or dura-tion less than the requirement of ISPM 15.

  3. Flight performance of Monochamus sartor and Monochamus sutor, potential vectors of the pine wood nematode

    Directory of Open Access Journals (Sweden)

    Putz Jasmin

    2016-12-01

    Full Text Available Flight performance of Monochamus sartor and Monochamus sutor, two potential vectors of the pine wood nematode, Bursaphelenchus xylophilus was evaluated in laboratory flight mill tests. Beetles emerging from logs infested in the laboratory and incubated under outdoor conditions as well as field collected beetles were used. The maximum distance flown by M. sartor in a single flight was 3,136.7 m. Mean distances (per beetle per flight ranged from 694.6 m in females to 872.5 m in males for M. sartor. In 75% of all individual flights M. sartor flew less than 1 km; only 3.7% flew distances longer than 2 km. The mean cumulative distance travelled by M. sartor beetles throughout their lifespan was 7.5 km. The smaller M. sutor beetles flew faster and longer distances. The maximum distance per flight was 5,556.5 m; mean distances ranged from 1,653.6 m in females to 1178.3 m in males. The number of available laboratory reared beetles was too low for quantification of lifetime flight capacity for M. sutor. The findings are compared to published data from Monochamus galloprovincialis recorded on the same type of flight mill as well as to field data from mark-release-recapture studies. The high flight capacity of Monochamus beetles illustrates the importance of considering dispersal of the vectors when planning control measures against the pine wood nematode.

  4. Hydrological and geomorphological consequences of beavers activity in the Struga Czechowska valley (Tuchola Pinewood Forest, Poland)

    Science.gov (United States)

    Brykała, Dariusz; Gierszewski, Piotr; Błaszkiewicz, Mirosław; Kordowski, Jarosław; Tyszkowski, Sebastian; Słowiński, Michał; Kaszubski, Michał; Brauer, Achim

    2016-04-01

    Since last years, after the process of beavers' (Castor fiber) reintroduction to the Polish environment, on the Struga Czechowska river (Tuchola Pinewood Forest, Poland) was observed large beaver activity, especially along the outlet from the Lake Głęboczek. It expresses in relief transformation of the valley bottom and its slopes. Created by beavers small ponds functioning as local sediment traps. Periodically the dams were destroyed. This led to rapid water drainage. The effects of such events were observed in the period between December 2014 and May 2015. Inventory of beaver dams along the Struga Czechowska river, which had made in 2015, shows that dams were distributed on average every 50 m. There were 30 dams on three sections of river. Only 6 were built there in 2015, and the remaining were older and abandoned, but one-third of them still damming water of stream. The average water damming by beaver dams amounts 0.2 m, and maximum 0.6 m. The width of the beaver dams reached there almost always the value of 3 m, and their height reached average up to 0.8 m was identical to the bankfull depth. Cascade character of the beaver dams operation has its consequences in functioning of erosional and accumulation parts of watercourses (alternately). Analysis of hydrograph of the Struga Czechowska water levels shows, that since December 2014 there were nine rapid drainages of beaver ponds located above the paleolake Trzechowskie. Damaged dams were very quickly rebuilt, and water in ponds was again stored. The average time of restoration the dam amounts 10 hours, and maximum 3 days. Rapid flows from beaver ponds resulted in intensive bottom and lateral erosion of stream channel and a creation of soil falls on the slopes of valley below destroyed dams. Products of erosion were accumulated along watercourse at a distance of 200 meters, and then in the stream channel in form of sandy bars. Especially intensive accumulation occurred at flat surface of paleolake. Maximum

  5. Roles of Steroids in Nematodes

    Science.gov (United States)

    The inability of nematodes to biosynthesize steroids de novo and the resulting dependence of parasitic nematodes upon their hosts have enhanced the importance of elucidating the metabolism of sterols and the hormonal and other functions of steroids in nematodes. Biochemical research has revealed th...

  6. Nematode cholinergic pharmacology

    Energy Technology Data Exchange (ETDEWEB)

    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 ({sup 3}H)N-methylscopolamine (({sup 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.

  7. 拟松材线虫携带细菌对云南松的致病性%Pathogenicity of bacterium carried by Bursaphelenchus mucronatus on Pinus yunnanensis

    Institute of Scientific and Technical Information of China (English)

    李姝江; 朱天辉; 张兴华

    2014-01-01

    Summary Pine wood nematode (PWN) is a destructive disease to pines.For the research on its pathogenic mechanism,the theory which is about the complex infection of PWN and the bacterium carried by it is recognized. Bursaphelenchus mucronatus is considered as a related species of Bursaphelenchus xylophilus ,which may be differentiation with the homologous species in different environments.In early studies,B.mucronatus was served as contrast species to B.xylophilus due to the weak or lacking pathogenicity.But recently,many reports have pointed out that it has the strong pathogenicity and can cause the widespread death of pines,which referred to Pinus thunbergii P.yunnanensis P.taiwanensis P.densata ,etc.The large numbers of P.yunnanensis were dead in Sichuan in recent years. However,no systematic study was conducted on the pathogenicity of the bacterium carried by B.mucronatus .This study has the aim of evaluating the effects of the bacterium carried by B.mucronatus on wilting ratio and phenylpropanoid metabolism of pine needles,and further exploring the effect of bacterium in the pathogenic process of B.mucronatus . Two-year-old P.yunnanensis seedlings,B.mucronatus isolated from PWN disease district in Sichuan,the bacterium carried by B.mucronatus and its metabolite as the materials,the wilting ratio was calculated,and the total phenol content, phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD) activities were determined by the inoculation of burette to branch phloem of P.yunnanensis in laboratory,which represented the pathogenicity of the bacterium and its metabolite on P.yunnanensis . The results showed that Pectobacterium cypripedii and its non-protein metabolite had strongest effect on P. yunnanensis in 26 species of bacteria isolated from the surface of nematodes,and the wilting degree and wilting ratio were significantly high in these two treatments.They caused the accumulation of total phenol content and the changes of PAL,PPO and

  8. Nematodes species survey and identification in the pine wood in Vietnam%越南松树枯死病症状及原因初步研究

    Institute of Scientific and Technical Information of China (English)

    Nguyen Thanh Tuan; Le Bao Thanh; 颜学武

    2016-01-01

    为查明越南松树枯死的原因,对越南南部的林同省,中部的承天-顺化省,北部的广宁省的思茅松、马尾松和南亚松枯死症状和原因进行了调查,分别从枯死、濒死、健康松树木质部中抽取52份样品,用于线虫分离镜检。调查发现松树在感病后,树冠部分针叶失去光泽,逐渐褪绿变黄,进而褐红干枯,最后整个树冠变为褐色或红褐色,全株枯死,针叶下垂且当年不落;随着病程的发展,松脂分泌逐渐减少,直至停止;树干上有天牛产卵刻槽,死亡的松树上有天牛的羽化孔。在抽取的松树样品中分离鉴定到了泰国伞滑刃线虫(Bur-saphelenchus thailandae Brassch &Brassch-Bidasak,2002),为病原的确定和防治工作提供初步的依据。%Pine wilt desease has caused great damage to the forestry and ecological system.It became the most destructive threat to pine wood production,and it has been regarded as important inspection object.This reseach takes nematodes as materials which were atained from blasted pines in Viet Nam country,because a lot of pines were dead for unknown rea-sons in many parts of Viet Nam country.The morphological identification of the nematode were conducted.A survey of nematodes on pine wood was conducted in Viet Nam country (Lam Dong province,Thua Thien Hue province,Quang Ninh province)from september 2012 to june 2013.Collect 52 samples from 3 provinces.These samples were taken from dead,dying and exterior healthy pines.We separated and cultured nematodes gained from blasted pines;measured and calculated the numerical value of V,a,b and so on;and described modality.Parasitic nematodes on pine were also i-dentified.The results showed that one species of the genus Bursaphelenchus were identified as B.thailandae .They were i-solated from new hosts, Kesiya pine (P.kesiya R.), Massoniana pine (P.massoniana L.), Merkusii pine (P.merkusii J.),respectively.Bursaphelenchus

  9. Scientific Opinion on a composting method proposed by Portugal as a heat treatment to eliminate pine wood nematode from the bark of pine trees

    DEFF Research Database (Denmark)

    Baker, R.; Candresse, T.; Dormannsné Simon, E.

    2010-01-01

    Following a request from the European Commission, the Panel on Plant Health was asked to deliver a scientific opinion on the appropriateness of a composting method proposed by Portugal as a heat treatment to eliminate pine wood nematode (PWN), Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle......) insufficient evidence on the sampling methodology is provided to determine the reliability of the testing method provided by the Portuguese document to determine freedom from PWN. Although there is potential for development of a composting method as a heat treatment to eliminate PWN from bark of pine trees......, the technical requirements presented in the Portuguese dossier do not adequately demonstrate the effectiveness and reliability of the proposed composting method as a treatment to ensure freedom of treated pine bark from live PWN...

  10. New frontiers in nematode ecology.

    Science.gov (United States)

    Ferris, H

    1993-09-01

    Future areas of emphasis for research and scholarship in nematode ecology are indicated by pressing agricultural and environmental issues, by new directions in applied nematology, and by current technological advances. Studies in nematode ecology must extend beyond observation, counting, and simple statistical analysis. Experimentation and the testing of hypotheses are needed for understanding the biological mechanisms of ecological systems. Opportunities for fruitful experimentation in nematode ecology are emerging at the ecosystem, community, population, and individual levels. Nematode ecologists will best promote their field of study by closely monitoring and participating in the advances, initiatives, developments, and directions in the larger field of ecology.

  11. Intestinal nematodes: biology and control.

    Science.gov (United States)

    Epe, Christian

    2009-11-01

    A variety of nematodes occur in dogs and cats. Several nematode species inhabit the small and large intestines. Important species that live in the small intestine are roundworms of the genus Toxocara (T canis, T cati) and Toxascaris (ie, T leonina), and hookworms of the genus Ancylostoma (A caninum, A braziliense, A tubaeforme) or Uncinaria (U stenocephala). Parasites of the large intestine are nematodes of the genus Trichuris (ie, whipworms, T vulpis). After a comprehensive description of their life cycle and biology, which are indispensable for understanding and justifying their control, current recommendations for nematode control are presented and discussed thereafter.

  12. Endobacteria from different virulence Bursaphelenchus mucronatus%拟松材线虫不同致病力虫株体内细菌的种类差异

    Institute of Scientific and Technical Information of China (English)

    袁为敏; 项杨; 吴小芹

    2015-01-01

    Bursaphelenchus mucronatus is one of plant parasitic nematodes and similar to the causative agent of pine wilt disease B. xylophilus in morphology. To understand the interaction between B. mucronatus and endobacteria, ten strains of B. mucronatus from seven provinces were inoculated to 2⁃year old Pinus thunbergii to evaluate their virulence. Besides, endobacteria of B. mucronatus were also isolated and analyzed. Pathogenic measurement showed that six strains of B. mucronatus were pathogenic to P. thunbergii, but the other four strains had no pathogenicity. Seventeen strains of endobacteria were isolated from 9 of 10 B. mucronatus strains. Physiological and biochemical characteristics, biolog methods combined with molecular revealed that seventeen strains of endobacteria belonged to Stenotrophomonas malto⁃philia, Ewingella americana, Pseudomonas fluorescens, Agrobacterium tumefaciens,Luteibacter anthropi, Microbacterium oxydans, Agreia pratensis, Leifsonia naganoensis and Achromobacter xylosoxidans ssp. xylosoxidans. Further analysis showed that species and population of endobacteria strains from virulent B. mucronatus strains were more abundant than that from non⁃virulent strains. S. maltophilia were usually isolated from virulent B. mucronatus strains, while endobacteria M. oxydans were mainly isolated from avirulent strains.%拟松材线虫( Bursaphelenchus mucronatus)为伞滑刃属植物寄生线虫,在形态上与引起松树萎蔫病( Pine Wild Disease)的松材线虫( B. xylophilus)极其相似。为探讨拟松材线虫的致病力与其体内细菌的关系,笔者将来自中国7省市不同地区的10个拟松材线虫虫株接种黑松测定其致病力,并对拟松材线虫的体内细菌进行了分离鉴定。结果表明,供试的10个拟松材线虫虫株中有6个虫株对黑松具致病力,4个虫株无致病力。通过分离拟松材线虫的体内细菌,发现有9个虫株体内存在细菌,共分离获得17

  13. Characteristics of hybridization between Bursaphelenchus xylophilus and B.mucronatus%松材线虫与拟松材线虫种间杂交特性研究

    Institute of Scientific and Technical Information of China (English)

    应晨希; 吴小芹

    2014-01-01

    选取来自中国、日本和美国的松材线虫( Bursaphelenchus xylophilus)4个虫株,以及中国的拟松材线虫( B. mucronatus)2个虫株进行生物学杂交和交配对象选择试验。结果表明:松材线虫和拟松材线虫的部分虫株可以发生种间杂交,正交总交配成功率为4�2%,反交总交配成功率为10%,反交成功率是正交的2倍。杂交整体发生率极低,杂交后代较难形成可持续的繁殖种群。采用松材线虫(简称Bx)/拟松材线虫(简称Bm)快速分子检测系统对杂交F1代幼虫进行分子鉴定,结果表明F1代幼虫既含有Bx分子标记也含有Bm分子标记。继代培养30 d后,杂交后代在基因型上表现出了不同趋向的分化,其中BxAN5♀×Bm JNL1♂、BxAN5♂×BmAN5♀和Bx⁃USA♂×Bm JNL1♀的杂交后代趋向于成为松材线虫占主导的种群,BxJNL5♂×BmJNL1♀的杂交后代趋向于成为拟松材线虫占主导的种群。在有种内交配资源存在情况下,无论松材线虫还是拟松材线虫均倾向于优先选择种内交配资源。研究表明松材线虫和拟松材线虫之间存在一定的生殖隔离,自然状态下种间交配可能会产生,但杂交后代较难形成可持续性繁殖的生殖后代。%In this study, the hybridization was conducted between four Bursaphelenchus xylophilus strains selected from China, Japan, the United States and two B. mucronatus strains selected from China. The results showed that, hybridiza⁃tion could occur between some B. xylophilus strains and B. mucronatus strains, the success rate of negative crossing was two times that of positive crossing,but hybridization rate was extremely low, and the hybrid offspring was difficult to form a sustainable breeding population. The F1 hybrids larvae contained both Bx molecular markers and Bm molecular markers by using Bx/Bm quick molecular detection system. Inter⁃specific hybrids showed different gene types

  14. The functional organisation of the mesopedobionts community of sod pinewood soils on arena of the river Dnepr

    Directory of Open Access Journals (Sweden)

    O. V. Zhukov

    2016-01-01

    Full Text Available We revealed the functional groups of the animals of sod pinewood soils (arena of the river Dnepr in the "Dneprovsko-Orelsky" Nature Reserve on the basis of cluster analysis of the RLQ-axes received as result of interaction of matrix of community, matrix of edaphic parameters and matrix of ecomorphs of soil animals. The quantitative account of soil mesofauna has allowed us to establish that the community of animals inhabiting sod pinewood soils is represented by 20 species at a density of 68.9 ± 14.6 ind./m2, 8 forms were identified at the level of genus, family or order. Two species were represented by their larval and imago phases (Anatolica eremita (Steven, 1829 and Calathus ambiguus (Paykull, 1790. A count of animals conducted in an alternative way has allowed us to expand the list to 38 species or forms at species level. The level of abundance and diversity for sod pinewood soils on the arena is not high compared with other types of soils of the arena of the river Dnepr. This result shows that the community has a simplified ecological structure. The prevailing ecological structure of the community can be characterised as steppe, xerophilous, oligotrophocoenomorphic. Anecic animals are absent from the topomorphic structure and saprophagous animals absent from the trophic structure. Only additional collection by alternative methods has allowed us to establish the presence in the community of saprophagous and anecic animals. The latter ecological group is represented by the extremely mobile vertebrate species Pelobates fuscus. The foromorphic structure of the community differs by its great variety. In this structure various strategies of animals’ movement through the soil are proportionately represented. On the one hand, we see various ways of movement of herpetobiont animals, mainly insect imagoes, which as a whole differ in their considerable migratory potential. This circumstance staticizes the historical reasons for the formation of the

  15. Bacteria can mobilize nematode-trapping fungi to kill nematodes.

    Science.gov (United States)

    Wang, Xin; Li, Guo-Hong; Zou, Cheng-Gang; Ji, Xing-Lai; Liu, Tong; Zhao, Pei-Ji; Liang, Lian-Ming; Xu, Jian-Ping; An, Zhi-Qiang; Zheng, Xi; Qin, Yue-Ke; Tian, Meng-Qing; Xu, You-Yao; Ma, Yi-Cheng; Yu, Ze-Fen; Huang, Xiao-Wei; Liu, Shu-Qun; Niu, Xue-Mei; Yang, Jin-Kui; Huang, Ying; Zhang, Ke-Qin

    2014-12-16

    In their natural habitat, bacteria are consumed by bacterivorous nematodes; however, they are not simply passive preys. Here we report a defensive mechanism used by certain bacteria to mobilize nematode-trapping fungi to kill nematodes. These bacteria release urea, which triggers a lifestyle switch in the fungus Arthrobotrys oligospora from saprophytic to nematode-predatory form; this predacious form is characterized by formation of specialized cellular structures or 'traps'. The bacteria significantly promote the elimination of nematodes by A. oligospora. Disruption of genes involved in urea transport and metabolism in A. oligospora abolishes the urea-induced trap formation. Furthermore, the urea metabolite ammonia functions as a signal molecule in the fungus to initiate the lifestyle switch to form trap structures. Our findings highlight the importance of multiple predator-prey interactions in prey defense mechanisms.

  16. Tornado project - The impact of catastrophic deforestation on the lake and peatland ecosystems of the Tuchola Pinewoods, Northern Poland

    Science.gov (United States)

    Słowiński, Michał; Lamentowicz, Mariusz; Łuców, Dominika; Kołaczek, Piotr; Tjallingii, Rik; Noryśkiewicz, Agnieszka M.; Zawiska, Izabela; Lane, Christine; Rzodkiewicz, Monika; Słowińska, Sandra; Kramkowski, Mateusz; Płóciennik, Mateusz; Tyszkowski, Sebastian; Łokas, Edyta; Kordowski, Jarosław; Brauer, Achim

    2017-04-01

    An increase in extreme weather phenomena has been observed over the last decades as a result of global climate warming. This project aims to investigate the effects of tornado events on the lake and peatland ecosystems of the Tuchola Pinewoods, Northern Poland. Deforestation by tornado events can cause severe perturbations of the soil hydrology and erosion that, in turn, affects adjacent lakes and peatlands. The Tuchola Pinewoods provide an exceptional possibility of studying the impact of such extreme events as it was struck by a tornado in 2012. This project focuses on lake - peatlands ecosystems that were directly affected by this tornado, with respect to the general transformation of the vegetation (mainly forests) over the last 300 years. Extensive clearing of the forest occurred in the nineteenth century due-to human agricultural activity, and we compare this with the impact of the 2012 tornado. Accurate reconstructions will rely on a broad range of palaeoecological techniques such as Cladocera, Chironomidae, diatoms, pollen, macroremains, testate amoebae, but also on geochemistry, i.e. μXRF scanning. We plan to analyses sediments of Kałębie and Martwe Lakes, as well as the adjacent Martwe peatland located along the path of the tornado. The chorology of the records collected will be based on 210Pb, 137Cs and radiocarbon dating as well as relative (crypto)tephra markers of the Eyjafjöll (2010) and Askja (1875) eruptions. This research addresses the emerging issue of the impact of extreme phenomena and more general climate changes on lake and peatland ecosystems, which potentially helps to adaptations to the environmental consequences of extreme events in the future. This project is funded by the Polish National Science Centre (No. 2015/17/B/ST10/03430) and is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution Analyses - ICLEA - of the Helmholtz Association and Science and Research Funds for 2015-2016, allocated to a co

  17. Social networks of educated nematodes

    Science.gov (United States)

    Entomopathogenic nematodes are obligate lethal parasitoids of insect larvae that navigate a chemically complex belowground environment while interacting with their insect hosts, plants, and each other. In this environment, prior exposure to volatile compounds appears to prime nematodes in a compound...

  18. 应用木腐菌处理松材线虫病疫木伐桩的研究%Study on Using Wood-rotting Fungi to Treat Stumps of Dead Wood Caused by PWN (Bursaphelenchus xylophilus)

    Institute of Scientific and Technical Information of China (English)

    邓习金; 刘晖; 罗惠文; 黄燕洪

    2014-01-01

    Diseased stumps is cure difficulty of pine wood nematode disease, it is an environmental protection, control technology effectively that using wood rotting fungi treated pine wood nematode infected stumps. In th is study, the 13 kinds of wood-rotting fungi were chosen to evaluate the irrelation with Bursaphelenchus xylophilus ( PWN ) , the ability to decompose the wood specimens of Pinus massoniana and the stumps of dead pine trees caused by PWN, by screening and propagating good strains of the wood-rotting fungi, and using to field test, the results showed that all the wood-rotting fungi tested had certa in nematicidal effects on PWN except Schizophyllum commune and Coriolus versicolor, and 6 strains could completely inhibit the pine wood nematode, they are Tremellodon gelatinosum, Fomitopsis pinicola, Pleurotus ostreatus, Laetiporus sulphureus, Poria cocos, Ganoderma lucidum. The test results of decomposing pine wood and disease stumps showed that they had played some decomposition effect to the diseased stumps, after treating stumps inoculating above 6 strains for 70 d, especially, Laetiporus sulphureus showed higher ability to decomposing and colonising the stumps,and inhibiting and killing nematodes, it could be used to treat stumps of dead wood caused by PWN in the future.%疫木伐桩是松材线虫病除治中的难点,利用木腐菌处理松材线虫病疫木伐桩是一项环保、有效的伐桩处理技术。本试验研究了13种木腐菌对松材线虫的抑制作用以及对马尾松木块和松材线虫病疫木伐桩的分解能力,通过对木腐菌的筛选、优良菌株的扩繁,将优良木腐菌应用于松材线虫病疫木伐桩野外试验,结果表明,供试菌株除裂褶菌和杂色云芝外,其他菌都能抑制松材线虫的生长与繁殖,其中虎掌菌、松生拟层孔菌、粗皮侧耳、硫磺菌、茯苓和灵芝等6个菌能完全抑制松材线虫的数量。对马尾松木块及疫木伐桩的分解试

  19. Epidemiological Characteristics and Control Methods of Bursaphelenchus xylophilus%松材线虫病的发病特征及防治方法

    Institute of Scientific and Technical Information of China (English)

    邓国松

    2015-01-01

    介绍了松材线虫病的病原及发病特征,并从清理病死树、病木除害处理、防治传媒松墨天牛等方面提出了松材线虫病防治方法,以期为松材线虫病的有效防治提供参考。%Pathogeny and epidemiological characteristics were introduced.Control methods of Bursaphelenchus xylophilus were put forwards,including clear-cutting dead pine trees,disease wood treatment,prevention and control the media of Monochamus alternatus Hope etc,so as to provide reference for the effective prevention and control of Bursaphelenchus xylophilus.

  20. Response of pine forest to disturbance of pine wood nematode with interpretative structural model

    Institute of Scientific and Technical Information of China (English)

    Juan SHI; Youqing LUO; Xiaosu YAN; Weiping CHEN; Ping JIANG

    2009-01-01

    Pine wood nematode (PWN, Bursaphelenchus xylophilus), originating from North America, causes destructive pine wilt disease. Different pine forest ecosystems have different resistances to B. xylophilus,and after its invasion, the resilience and restoration direction of different ecosystems also varies. In this study, an interpretative structural model was applied for analyzing the response of pine forest ecosystem to PWN disturbance. The result showed that a five-degree multi-stage hierarchical system affected the response of the pine forest ecosystem to PWN disturbance, in which direct affecting factors are resistance and resilience. Furthermore,the analysis to the 2nd, 3rd and 4th degree factors showed that not only does distribution pattern of plant species and pine's ecological features affect the resistance of pine forests' ecosystem, but removal of attacked trees and other measures also influence the resistance through indirectly affecting the damage degree of Monochamus alternatus and distribution pattern of plant species. As for resilience,it is influenced directly by soil factors, hydrology,surrounding species provenance and biological character-istics of the second and jointly dominant species, and the climate factors can also have a direct or indirect effect on it by affecting the above factors. Among the fifth elements,the elevation, gradient and slope direction, topographical factors, diversity of geographical location and improve-ment of prevention technology all influence the response of pine forest ecosystem to PWN disturbance.

  1. Two species nematodes of the genus Bursa phelenchus in China (Nematoda..Parasitaphelenchidae)%中国2种伞滑刃属线虫记述(线虫门:寄生滑刃科)

    Institute of Scientific and Technical Information of China (English)

    卓侃; 王宏洪; 李迅东; 廖金铃

    2011-01-01

    运用线虫比较形态学和rDNA-ITS-RFLP及rDNA-ITS序列分析技术,对采自广东省的伞滑刃线虫进行鉴定.在广东番禺小叶榕(Ficus microcarpa)的栽培介质中和东莞木包装上分别发现了食菌伞滑刃线虫(Bursaphelenchus fungivorus)和豆伞滑刃线虫(B.doui),其中食菌伞滑刃线虫是中国的新记录种,豆伞滑刃线虫是中国大陆的新记录种.%Nematodes of the genus Bursaphelenchus collected from Guangdong Province were identified by using morphology, rDNA-ITS-RFLP and rDNA-ITS-PCR-sequencing.B.fungivorus and B.doui were isolated from a growing substrate for Ficus microcarpa in Panyu and wood packaging material in Dongguan respectively.B.fungivorus was a new geographic record species in China, and B.doui was a new geographic record species in Chinese Mainland.

  2. Effects of saltwater intrusion on pinewood vegetation using satellite ASTER data: the case study of Ravenna (Italy).

    Science.gov (United States)

    Barbarella, M; De Giglio, M; Greggio, N

    2015-04-01

    The San Vitale pinewood (Ravenna, Italy) is part of the remaining wooded areas within the southeastern Po Valley. Several studies demonstrated a widespread saltwater intrusion in the phreatic aquifer caused by natural and human factors in this area as the whole complex coastal system. Groundwater salinization affects soils and vegetation, which takes up water from the shallow aquifer. Changes in groundwater salinity induce variations of the leaf properties and vegetation cover, recognizable by satellite sensors as a response to different spectral bands. A procedure to identify stressed areas from satellite remote sensing data, reducing the expensive and time-consuming ground monitoring campaign, was developed. Multispectral Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data, acquired between May 2005 and August 2005, were used to calculate Normalized Difference Vegetation Index (NDVI). Within the same vegetation type (thermophilic deciduous forest), the areas with the higher vegetation index were taken as reference to identify the most stressed areas using a statistical approach. To confirm the findings, a comparison was conducted using contemporary groundwater salinity data. The results were coherent in the areas with highest and lowest average NDVI values. Instead, to better understand the behavior of the intermediate areas, other parameters influencing vegetation (meteorological data, water table depth, and tree density) were added for the interpretation of the results.

  3. The Physical and Chemical Properties of Fine Carbon Particles-Pinewood Resin Blends and Their Possible Utilization

    Directory of Open Access Journals (Sweden)

    Aviwe Melapi

    2015-01-01

    Full Text Available The application of biomass gasification technology is very important in the sense that it helps to relieve the dwindling supply of natural gas from fossil fuels, and the desired product of its gasification process is syngas. This syngas is a mixture of CO and H2; however, by-products such as char, tar, soot, ash, and condensates are also produced. This study, therefore, investigated selected by-products recovered from the gasification process of pinewood chips with specific reference to their potential application in other areas when used as blends. Three samples of the gasification by-products were obtained from a downdraft biomass gasifier system and were characterized in terms of chemical and physical properties. FTIR analysis confirmed similar spectra in all char-resin blends. For fine carbon particles- (soot- resin blends, almost the same functional groups as observed in char-resin blends appeared. In bomb calorimeter measurements, 70% resin/30% char blends gave highest calorific value, followed by 50% resin/50% soot blends with values of 35.23 MJ/kg and 34.75 MJ/kg consecutively. Provided these by-products meet certain criteria, they could be used in other areas such as varnishes, water purification, and wind turbine blades.

  4. BORON CONCENTRATION IN HUMIC AND FULVIC ACID EXTRACTS OF SOIL EPIPEDON IN SAN VITALE PINEWOOD (RAVENNA, ITALY

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    Maddalena Pennisi

    2010-08-01

    Full Text Available Humified Soil Organic Matter (SOM plays a crucial role in the assessment of soil quality since it makes up a significant part of the total organic carbon and nitrogen in soils. High concentrations of humic and fulvic acids may be presents in soils and subordinately in sediments. These substances can potentially act as a significant reservoir of adsorbed boron as well as a source of this element to soil solution, rivers, and lakes. The aim of this study was to investigate boron in humic substances (e.g. humic and fulvic acids of soil epipedon. The San Vitale pinewood was selected as the study site and three samples - classified as Sodic Psammaquents and Typic Psammaquants - of the A1-horizon epipedon were analyzed for humic and fulvic acids and boron contents. The knowledge of the mechanisms of boron interaction with SOM is important for a better understanding of the water/rock interaction in the superficial soil environment, and to envisage the application of the blending of boron into humic acid granules in agricultural practices.

  5. Altering bio-oil composition by catalytic treatment of pinewood pyrolysis vapors over zeolites using an auger - packed bed integrated reactor system

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    Vamshi Krishna Guda

    2016-09-01

    Full Text Available Pine wood pyrolysis vapors were catalytically treated using Zeolite catalysts. An auger fed reactor was used for the pinewood pyrolysis while a packed bed reactor mounted on the top of the auger reactor housed the catalyst for the treatment of pinewood pyrolytic vapors. The pyrolytic vapors produced at 450 oC were passed through zeolite catalysts maintained at 425 oC at a weight hourly space velocity (WHSV of 12 h-1. Five zeolites, including ZSM-5, mordenite, ferrierite, Zeolite-Y, and Zeolite-beta (all in H form, were used to study the effect of catalyst properties such as acidity, pore size, and pore structure on catalytic cracking of pinewood pyrolysis vapors. Product bio-oils were analyzed for their chemical composition using GC-MS, water content, density, viscosity, acid value, pH, and elemental compositions. Thermogravimetric analysis (TGA was performed to analyze the extent of coking on zeolite catalysts. Application of catalysis to biomass pyrolysis increased gas product yields at the expense of bio-oil yields. While all the zeolites deoxygenated the pyrolysis vapors, ZSM-5 was found to be most effective. The ZSM-5 catalyzed bio-oil, rich in phenolics and aromatic hydrocarbons, was less viscous, had relatively lower acid number and high pH, and possessed oxygen content nearly half that of un-catalyzed bio-oil. Brønsted acidity, pore size, and shape-selective catalysis of ZSM-5 catalyst proved to be the determining factors for its activity. TGA results implied that the pore size of catalysts highly influenced coking reactions. Regeneration of the used catalysts was successfully completed at 700 oC.

  6. Nematode-trapping fungi eavesdrop on nematode pheromones.

    Science.gov (United States)

    Hsueh, Yen-Ping; Mahanti, Parag; Schroeder, Frank C; Sternberg, Paul W

    2013-01-07

    The recognition of molecular patterns associated with specific pathogens or food sources is fundamental to ecology and plays a major role in the evolution of predator-prey relationships. Recent studies showed that nematodes produce an evolutionarily highly conserved family of small molecules, the ascarosides, which serve essential functions in regulating nematode development and behavior. Here, we show that nematophagous fungi, natural predators of soil-dwelling nematodes, can detect and respond to ascarosides. Nematophagous fungi use specialized trapping devices to catch and consume nematodes, and previous studies demonstrated that most fungal species do not produce traps constitutively but rather initiate trap formation in response to their prey. We found that ascarosides, which are constitutively secreted by many species of soil-dwelling nematodes, represent a conserved molecular pattern used by nematophagous fungi to detect prey and trigger trap formation. Ascaroside-induced morphogenesis is conserved in several closely related species of nematophagous fungi and occurs only under nutrient-deprived conditions. Our results demonstrate that microbial predators eavesdrop on chemical communication among their metazoan prey to regulate morphogenesis, providing a striking example of predator-prey coevolution. We anticipate that these findings will have broader implications for understanding other interkingdom interactions involving nematodes, which are found in almost any ecological niche on Earth.

  7. Social Networks of Educated Nematodes.

    Science.gov (United States)

    Willett, Denis S; Alborn, Hans T; Duncan, Larry W; Stelinski, Lukasz L

    2015-09-25

    Entomopathogenic nematodes are obligate lethal parasitoids of insect larvae that navigate a chemically complex belowground environment while interacting with their insect hosts, plants, and each other. In this environment, prior exposure to volatile compounds appears to prime nematodes in a compound specific manner, increasing preference for volatiles they previously were exposed to and decreasing attraction to other volatiles. In addition, persistence of volatile exposure influences this response. Longer exposure not only increases preference, but also results in longer retention of that preference. These entomopathogenic nematodes display interspecific social behavioral plasticity; experienced nematodes influence the behavior of different species. This interspecific social behavioral plasticity suggests a mechanism for rapid adaptation of belowground communities to dynamic environments.

  8. Using nematodes in soil ecotoxicology.

    Science.gov (United States)

    Sochová, Ivana; Hofman, Jakub; Holoubek, Ivan

    2006-04-01

    Nematodes represent a very abundant group of soil organisms and non-parasitic species are important for soil quality and in the soil food web. In recent years, it has been shown that nematodes are appropriate bioindicators of soil condition and they are also suitable organisms for laboratory toxicity testing. The aims of this paper are to overview and critically assess methods and approaches for researching soil nematode ecotoxicology. In natural ecosystems, nematode abundance and community structure analyses were proved to be sensitive indicators of stress caused by soil pollutants and ecological disturbance. Community structure analyses may be approached from a functional or ecological point of view; species are divided into groups according to their feeding habits or alternatively the maturity index is calculated according to their ecological strategy. Many environmental factors have the potential to affect nematode community, which consequently results in high space and time variability. This variance is major handicap in field ecotoxicological studies because pollutant-nematode relationships are obscured. For prospective risk assessment of chemicals, several toxicity tests with nematodes were developed and are increasingly used. Sensitivity of these tests is comparable to tests with other soil species (e.g. enchytraeids, earthworms and springtails) while tests are less demanding to space and time. Most studies have focused on metal toxicity but organic compounds are almost overlooked. Endpoints used in tests were often mortality, reproduction or movement, but more sublethal endpoints such as feeding or biomarkers have been used recently too. Although there is an increasing amount of knowledge in soil nematode ecotoxicology, there is still a lot of various issues in this topic to research.

  9. The Geological Record of Parasitic Nematode Evolution.

    Science.gov (United States)

    Poinar, George O

    2015-01-01

    This chapter discusses the evolutionary history of nematode parasites of invertebrates, vertebrates and plants based on fossil remains in amber, stone and coprolites dating from the Palaeozoic to the Holocene. The earliest parasitic nematode is a primitive plant parasite from the Devonian. Fossil invertebrate-parasitic nematodes first appeared in the Early Cretaceous, while the earliest fossil vertebrate-parasitic nematodes are from Upper Triassic coprolites. Specific examples of fossil nematode parasites over time are presented, along with views on the origin and evolution of nematodes and their hosts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Characterization and Comparison of Fast Pyrolysis Bio-oils from Pinewood, Rapeseed Cake, and Wheat Straw Using 13C NMR and Comprehensive GC × GC

    Science.gov (United States)

    2016-01-01

    Fast pyrolysis bio-oils are feasible energy carriers and a potential source of chemicals. Detailed characterization of bio-oils is essential to further develop its potential use. In this study, quantitative 13C nuclear magnetic resonance (13C NMR) combined with comprehensive two-dimensional gas chromatography (GC × GC) was used to characterize fast pyrolysis bio-oils originated from pinewood, wheat straw, and rapeseed cake. The combination of both techniques provided new information on the chemical composition of bio-oils for further upgrading. 13C NMR analysis indicated that pinewood-based bio-oil contained mostly methoxy/hydroxyl (≈30%) and carbohydrate (≈27%) carbons; wheat straw bio-oil showed to have high amount of alkyl (≈35%) and aromatic (≈30%) carbons, while rapeseed cake-based bio-oil had great portions of alkyl carbons (≈82%). More than 200 compounds were identified and quantified using GC × GC coupled to a flame ionization detector (FID) and a time of flight mass spectrometer (TOF-MS). Nonaromatics were the most abundant and comprised about 50% of the total mass of compounds identified and quantified via GC × GC. In addition, this analytical approach allowed the quantification of high value-added phenolic compounds, as well as of low molecular weight carboxylic acids and aldehydes, which exacerbate the unstable and corrosive character of the bio-oil. PMID:27668136

  11. Characterization and Comparison of Fast Pyrolysis Bio-oils from Pinewood, Rapeseed Cake, and Wheat Straw Using (13)C NMR and Comprehensive GC × GC.

    Science.gov (United States)

    Negahdar, Leila; Gonzalez-Quiroga, Arturo; Otyuskaya, Daria; Toraman, Hilal E; Liu, Li; Jastrzebski, Johann T B H; Van Geem, Kevin M; Marin, Guy B; Thybaut, Joris W; Weckhuysen, Bert M

    2016-09-06

    Fast pyrolysis bio-oils are feasible energy carriers and a potential source of chemicals. Detailed characterization of bio-oils is essential to further develop its potential use. In this study, quantitative (13)C nuclear magnetic resonance ((13)C NMR) combined with comprehensive two-dimensional gas chromatography (GC × GC) was used to characterize fast pyrolysis bio-oils originated from pinewood, wheat straw, and rapeseed cake. The combination of both techniques provided new information on the chemical composition of bio-oils for further upgrading. (13)C NMR analysis indicated that pinewood-based bio-oil contained mostly methoxy/hydroxyl (≈30%) and carbohydrate (≈27%) carbons; wheat straw bio-oil showed to have high amount of alkyl (≈35%) and aromatic (≈30%) carbons, while rapeseed cake-based bio-oil had great portions of alkyl carbons (≈82%). More than 200 compounds were identified and quantified using GC × GC coupled to a flame ionization detector (FID) and a time of flight mass spectrometer (TOF-MS). Nonaromatics were the most abundant and comprised about 50% of the total mass of compounds identified and quantified via GC × GC. In addition, this analytical approach allowed the quantification of high value-added phenolic compounds, as well as of low molecular weight carboxylic acids and aldehydes, which exacerbate the unstable and corrosive character of the bio-oil.

  12. Molecular Characterization and Functional Analysis of Three Pathogenesis-Related Cytochrome P450 Genes from Bursaphelenchus xylophilus (Tylenchida: Aphelenchoidoidea

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    Xiao-Lu Xu

    2015-03-01

    Full Text Available Bursaphelenchus xylophilus, the causal agent of pine wilt disease, causes huge economic losses in pine forests. The high expression of cytochrome P450 genes in B. xylophilus during infection in P. thunbergii indicated that these genes had a certain relationship with the pathogenic process of B. xylophilus. Thus, we attempted to identify the molecular characterization and functions of cytochrome P450 genes in B. xylophilus. In this study, full-length cDNA of three cytochrome P450 genes, BxCYP33C9, BxCYP33C4 and BxCYP33D3 were first cloned from B. xylophilus using 3' and 5' RACE PCR amplification. Sequence analysis showed that all of them contained a highly-conserved cytochrome P450 domain. The characteristics of the three putative proteins were analyzed with bioinformatic methods. RNA interference (RNAi was used to assess the functions of BxCYP33C9, BxCYP33C4 and BxCYP33D3. The results revealed that these cytochrome P450 genes were likely to be associated with the vitality, dispersal ability, reproduction, pathogenicity and pesticide metabolism of B. xylophilus. This discovery confirmed the molecular characterization and functions of three cytochrome P450 genes from B. xylophilus and provided fundamental information in elucidating the molecular interaction mechanism between B. xylophilus and its host plant.

  13. Application and commercialization of nematodes.

    Science.gov (United States)

    Peters, Arne

    2013-07-01

    While nematodes are most commonly known for their negative impact on plants, animals, and humans, there are a number of species which are commercially explored. This review highlights some of the most important success stories for the application of nematodes. They are used as bioindicators in ecological and toxicity studies, as model organisms for elucidating fundamental biological questions and for high throughput screening of drugs. Besides these indirect uses, direct applications include the use of Beddingia siricidicola against a major forest pest and the commercialization of Steinernema, Heterorhabditis, and Phasmarhabditis as biological pest control products. New directions for the commercialization of nematodes are the use as living food, specifically loaded with essential nutrients for various fish and shrimp larvae. Even human parasites or closely related species have been successfully used for curing autoimmune disorders and are currently in the process of being developed as drugs. With the striving development of life sciences, we are likely to see more applications for nematodes in the future. A prerequisite is that we continue to explore the vast number of yet undiscovered nematode species.

  14. Nematode neuropeptides as transgenic nematicides.

    Science.gov (United States)

    Warnock, Neil D; Wilson, Leonie; Patten, Cheryl; Fleming, Colin C; Maule, Aaron G; Dalzell, Johnathan J

    2017-02-01

    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.

  15. Impact of conservation tillage on nematode populations.

    Science.gov (United States)

    Minton, N A

    1986-04-01

    Literature reporting the development of conservation tillage and the research that has been conducted on nematode control in crops grown in conservation tillage systems is reviewed. Effects of different types of conservation tillage on population densities of various nematode species in monocropping and multicropping systems, effects of tillage on nematode distribution in the soil profile, effects of conservation tillage on nematode control, and the role of nematology in conservation tillage research are discussed.

  16. Characterization of resistance to pine wood nematode infection in Pinus thunbergii using suppression subtractive hybridization

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    Hirao Tomonori

    2012-01-01

    Full Text Available Abstract Background Pine wilt disease is caused by the pine wood nematode, Bursaphelenchus xylophilus, which threatens pine forests and forest ecosystems worldwide and causes serious economic losses. In the 40 years since the pathogen was identified, the physiological changes occurring as the disease progresses have been characterized using anatomical and biochemical methods, and resistant trees have been selected via breeding programs. However, no studies have assessed the molecular genetics, e.g. transcriptional changes, associated with infection-induced physiological changes in resistant or susceptible trees. Results We constructed seven subtractive suppression hybridization (SSH cDNA libraries using time-course sampling of trees inoculated with pine wood nematode at 1, 3, or 7 days post-inoculation (dpi in susceptible trees and at 1, 3, 7, or 14 dpi in resistant trees. A total of 3,299 sequences was obtained from these cDNA libraries, including from 138 to 315 non-redundant sequences in susceptible SSH libraries and from 351 to 435 in resistant SSH libraries. Using Gene Ontology hierarchy, those non-redundant sequences were classified into 15 subcategories of the biological process Gene Ontology category and 17 subcategories of the molecular function category. The transcriptional components revealed by the Gene Ontology classification clearly differed between resistant and susceptible libraries. Some transcripts were discriminative: expression of antimicrobial peptide and putative pathogenesis-related genes (e.g., PR-1b, 2, 3, 4, 5, 6 was much higher in susceptible trees than in resistant trees at every time point, whereas expression of PR-9, PR-10, and cell wall-related genes (e.g., for hydroxyproline-rich glycoprotein precursor and extensin was higher in resistant trees than in susceptible trees at 7 and 14 dpi. Conclusions Following inoculation with pine wood nematode, there were marked differences between resistant and susceptible trees

  17. Host deception: predaceous fungus, Esteya vermicola, entices pine wood nematode by mimicking the scent of pine tree for nutrient.

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    Feng Lin

    Full Text Available BACKGROUND: A nematophagous fungus, Esteya vermicola, is recorded as the first endoparasitic fungus of pine wood nematode (PWN, Bursaphelenchus xylophilus, in last century. E. vermicola exhibited high infectivity toward PWN in the laboratory conditions and conidia spraying of this fungus on Japanese red pine, Pinus densiflora, seedlings in the field protected the pine trees from pine wilt disease to some extent, indicating that it is a potential bio-control agent against PWN. Previous research had demonstrated that the living fungal mycelia of E. vermicola continuously produced certain volatile organic compounds (VOCs, which were responsible for the PWN attraction. However, identity of these VOCs remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we report the identification of α-pinene, β-pinene, and camphor produced by living mycelia of E. vermicola, the same volatile compounds emitted from PWN host pine tree, as the major VOCs for PWN attraction using gas chromatography-mass spectrometry (GC-MS. In addition, we also confirmed the host deception behavior of E. vermicola to PWN by using synthetic VOCs in a straightforward laboratory bioassay. CONCLUSIONS/SIGNIFICANCE: This research result has demonstrated that the endoparasitic nematophagous fungus, E. vermicola, mimics the scent of PWN host pine tree to entice PWN for the nutrient. The identification of the attractive VOCs emitted from the fungus E. vermicola is of significance in better understanding parasitic mechanism of the fungus and the co-evolution in the two organisms and will aid management of the pine wilt disease.

  18. Plant Nematodes Occurring in Arkansas

    OpenAIRE

    Wehunt, E. J.; Golden, A. M.; Robbins, R. T.

    1989-01-01

    A total of 110 species of plant nematodes were found in various habitats in Arkansas. Thirty species from 19 genera are reported here for the first time. Included in the new reports are the known plant pathogens Criconemella onoense, Hirshmanniella oryzae, Longidorus elongatus, and Pratylenchus pratensis.

  19. Nematode Indicators of Organic Enrichment

    NARCIS (Netherlands)

    Ferris, H.; Bongers, A.M.T.

    2006-01-01

    The organisms of the soil food web, dependent on resources from plants or on amendment from other sources, respond characteristically to enrichment of their environment by organic matter. Primary consumers of the incoming substrate, including bacteria, fungi, plant-feeding nematodes, annelids, and

  20. Nematode Indicators of Organic Enrichment

    NARCIS (Netherlands)

    Ferris, H.; Bongers, A.M.T.

    2006-01-01

    The organisms of the soil food web, dependent on resources from plants or on amendment from other sources, respond characteristically to enrichment of their environment by organic matter. Primary consumers of the incoming substrate, including bacteria, fungi, plant-feeding nematodes, annelids, and s

  1. Anthelmintic resistance in equine nematodes

    Science.gov (United States)

    Matthews, Jacqueline B.

    2014-01-01

    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 diagnostics

  2. 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

  3. Diatoms as paleoecological indicators of environmental change in the Lake Czechowskie catchments ecosystem (Northern Tuchola Pinewoods, Poland)

    Science.gov (United States)

    Rzodkiewicz, Monika; Zawiska, Izabela; Noryśkiewicz, Agnieszka Maria; Obremska, Milena; Ott, Florian; Kramkowski, Mateusz; Słowiński, Michał; Błaszkiewicz, Mirosław; Brauer, Achim

    2016-04-01

    In this study we investigated four cores of biogenic sediments from the lakes located in close vicinity. Three cores are situated along a transect in the Lake Czechowskie basin from its deepest point towards a former lake bay. The fourth sediment core was retrieved from the nearby Trzechowskie paleolake. Lake Czechowskie is located in the northern part of the Tuchola Pinewoods District (Northern Poland) in a young glacial landscape. At present, the majority of the area is forested or used for agriculture. The main focus was of the study was Late Glacial and early Holocene period. We performed diatom, Cladocera and pollen analyses, the chronology was established by varve counting, confirmed by AMS 14C dating and Laacher See Tephra (Wulf et. all 2013). In this study we focused on the results of diatom analyses. Diatom assemblages are integrated indicators of environmental change because their distributions are closely linked to water quality parameters including such as nutrient availability. At the beginning of Allerød there are more eutrophic diatom taxa such as Staurosira construens, Pseudostaurosira brevistriata, Staurosira pinnata. These species are widely distributed in the littoral mainly freshwater, many of which are species of epiphytic, preferring water rich in nutrients. At the end of the Allerød we observe significant changes within diatom assemblages. The increase of planktonic Cyclotella comensis together with the decrease of benthic Stauroseria construens indicate the shortening of time with ice cove on the lake and longer time with summer stratification. In the Younger Dryas cooling we can see the increase of the abundance of diatom Staurosira construens which indicate cold spring and late ice-out (Bradbury et al., 2002). At the early Holocene planktonic diatoms increase in particular Cyclotella comensis, Punciculata radiosa and Cyclotella praetermissa. Some of Aulacoseira species at the end of Younger Dryas. The Holocene sediments showed no

  4. Experimental Evolution with Caenorhabditis Nematodes

    Science.gov (United States)

    Teotónio, Henrique; Estes, Suzanne; Phillips, Patrick C.; Baer, Charles F.

    2017-01-01

    The hermaphroditic nematode Caenorhabditis elegans has been one of the primary model systems in biology since the 1970s, but only within the last two decades has this nematode also become a useful model for experimental evolution. Here, we outline the goals and major foci of experimental evolution with C. elegans and related species, such as C. briggsae and C. remanei, by discussing the principles of experimental design, and highlighting the strengths and limitations of Caenorhabditis as model systems. We then review three exemplars of Caenorhabditis experimental evolution studies, underlining representative evolution experiments that have addressed the: (1) maintenance of genetic variation; (2) role of natural selection during transitions from outcrossing to selfing, as well as the maintenance of mixed breeding modes during evolution; and (3) evolution of phenotypic plasticity and its role in adaptation to variable environments, including host–pathogen coevolution. We conclude by suggesting some future directions for which experimental evolution with Caenorhabditis would be particularly informative. PMID:28592504

  5. Survey of Nematodes on Coffee in Hawaii

    OpenAIRE

    Schenck, S; Schmitt, D. P.

    1992-01-01

    Surveys of coffee fields in Hawaii during 1989-1991 indicated the presence of 10 nematode species in 8 genera. After coffee was planted in fields previously in sugarcane, populations of Criconemella sp. and Pratylenchus zeae gradually decreased, while Rotylenchulus reniformis and, in one field, Meloidogyne incognita, increased in numbers. Coffee is a poor host of R. reniformis, but weeds in coffee plantations may support this nematode. At present, nematodes pose no serious threat to Hawaii's ...

  6. Preparation of Pinewood- and Wheat Straw-based Activated Carbon via a Microwave-assisted Potassium Hydroxide Treatment and an Analysis of the Effects of the Microwave Activation Conditions

    Directory of Open Access Journals (Sweden)

    Haiyan Mao

    2014-12-01

    Full Text Available This study explored the effect of activated carbon preparation conditions on their adsorption performance. Pinewood and wheat straw were used as source materials to prepare activated carbon via a fast activation process using KOH and microwave heating. The iodine numbers and carbon yields were determined to evaluate the adsorption properties of the activated carbon. The effects of various KOH/char mass ratios, particle sizes, humidity levels, and microwave heating times on the physical characteristics of the activated carbon were investigated. The iodine number and yield and SEM images were used to characterize the activated carbon. Small particle sizes, the presence of humidity in the purge gas, and high KOH/char ratios resulted in higher iodine numbers. The best activated carbons were obtained using a KOH/char ratio of 3.0, a microwave power of 600 W, a radiation time of 30 min, and a particle size of 0.1 to 0.42 mm in a humid environment; these carbons showed iodine numbers of 2208 mg/g (pinewood activated carbon and 1420 mg/g (wheat straw activated carbon, with carbon yields of 73% and 52%, respectively. Longer microwave heating times increased the iodine number. The iodine numbers and yields of the pinewood activated carbons were much higher than those of their wheat straw counterparts.

  7. Developing sustainable systems for nematode management.

    Science.gov (United States)

    Barker, K R; Koenning, S R

    1998-01-01

    Early researchers identified key concepts and developed tactics for multiple-option management of nematodes. Although the emphasis on integrated pest management over the past three decades has promoted strategies and tactics for nematode management, comprehensive studies on the related soil biology-ecology are relatively recent. Traditional management tactics include host resistance (where available), cultural tactics such as rotation with nonhosts, sanitation and avoidance, and destruction of residual crop roots, and the judicious use of nematicides. There have been advances in biological control of nematodes, but field-scale exploitation of this tactic remains to be realized. New technologies and resources are currently becoming central to the development of sustainable systems for nematode-pest-crop management: molecular diagnostics for nematode identification, genetic engineering for host resistance, and the elucidation and application of soil biology for general integrated cropping systems. The latter strategy includes the use of nematode-pest antagonistic cover crops, animal wastes, and limited tillage practices that favor growth-promoting rhizobacteria, earthworms, predatory mites, and other beneficial organisms while suppressing parasitic nematodes and other plant pathogens. Certain rhizobacteria may induce systemic host resistance to nematodes and, in some instances, to foliage pathogens. The systems focusing on soil biology hold great promise for sustainable crop-nematode management, but only a few research programs are currently involved in this labor-intensive endeavor.

  8. Toxicity of Thirty-six Chinese Medicinal Herbs against Bursaphelenchus xylophilus%36种中草药提取物杀松材线虫活性研究

    Institute of Scientific and Technical Information of China (English)

    焦宏伟; 张璐; 赵宝华; 刘东

    2014-01-01

    为了从中草药中寻找高效杀线虫活性物质,本文测定了36种中草药提取物对松材线虫及其卵的毒杀活性。结果表明,牡丹皮、黄连和大黄3种中药的乙醇提取物杀线虫活性较强,以提取物浓度为10 g/L处理松材线虫72 h后,校正死亡率均为100%。3种中药提取物处理松材线虫72 h后半致死浓度(LC50)分别为1.81、0.2638和1.07 g/L。杀卵活性结果表明,3种中药提取物处理72 h后,线虫卵的孵化率均低于20%,虫卵的校正死亡率均高于60%。利用乙酸乙酯和水作溶剂对3种中草药进行初步的杀线活性成分分离的结果表明,牡丹皮的杀线活性物质存在于乙酸乙酯萃取物中,黄连和大黄的杀线活性物质存在于水萃取物中。3种中药的不同萃取物处理松材线虫72 h后的LC50分别为0.712、2.370和0.067 g/L。%Toxicity of ethanol extracts of thirty-six traditional Chinese medicinal (TCM) herbs to adult nematodes and eggs of Bursaphelenchus xylophilus were evaluated in this study to find efficient nematicidal compounds. Bioassay results showed that the ethanol extracts of Cortex moutan radicis, Coptis chinensis franch and Radix et rhizomarhei possessed excellent efficacy with 100%mortality of adults, less than 20%egg hatching rate and more than 60%mortality of eggs at the concentration of 10 g/L. The LC50 of ethanol extracts of three TCM herbs were 1.81, 0.2638 and 1.07 g/L respectively against B. xylophilus after treatment of 72 h. Preliminary separation of active ingredients of three TCM herbs using ethyl acetate and water was employed to examine the nematicide activities of the extracts. The active ingredients of C. moutan radicis presented in ethyl acetate extract, while the active ingredients of C. chinensis franch and R. et rhizomarhei presented in water extracts. The LC50 of active ingredients from three TCM herbs were 0.712, 2.370 and 0.067 g/L respectively against B. xylophilus after

  9. 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 of nematode

  10. 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 ...... extracts. Our results, therefore, indicated that tannin-containing plants could act against cattle nematodes....

  11. Isolation of pristionchus nematodes from beetles.

    Science.gov (United States)

    Rae, Robbie; Schlager, Benjamin; Sommer, Ralf J

    2008-10-01

    INTRODUCTIONIn this procedure, nematodes disembark from a beetle carcass and feed on Escherichia coli OP50. The nematodes are then monitored for a few days and identified using simple morphological characteristics. This method is rapid, easy, and biased for Pristionchus species.

  12. Nematodes ultrastructure: complex systems and processes.

    Science.gov (United States)

    Basyoni, Maha M A; Rizk, Enas M A

    2016-12-01

    Nematode worms are among the most ubiquitous organisms on earth. They include free-living forms as well as parasites of plants, insects, humans and other animals. Recently, there has been an explosion of interest in nematode biology, including the area of nematode ultrastructure. Nematodes are round with a body cavity. They have one way guts with a mouth at one end and an anus at the other. They have a pseudocoelom that is lined on one side with mesoderm and on the other side with endoderm. It appears that the cuticle is a very complex and evolutionarily plastic feature with important functions involving protection, body movement and maintaining shape. They only have longitudinal muscles so; they seem to thrash back and forth. While nematodes have digestive, reproductive, nervous and excretory systems, they do not have discrete circulatory or respiratory systems. Nematodes use chemosensory and mechanosensory neurons embedded in the cuticle to orient and respond to a wide range of environmental stimuli. Adults are made up of roughly 1000 somatic cells and hundreds of those cells are typically associated with the reproductive systems. Nematodes ultrastructure seeks to provide studies which enable their use as models for diverse biological processes including; human diseases, immunity, host-parasitic interactions and the expression of phylogenomics. The latter has, however, not been brought into a single inclusive entity. Consequently, in the current review we tried to provide a comprehensive approach to the current knowledge available for nematodes ultrastructures.

  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.

  14. Blends of ascarosides regulate dispersal in nematodes

    Science.gov (United States)

    Blends of ascarosides regulate dispersal in nematodes Presenter: Dr. Fatma Kaplan Dispersal is an important behavior for many organisms. It can easily be observed when infectious juveniles of entomopathogenic nematodes (Steinernema and Heterorhabditis) leave a consumed insect host. Dauer larvae of ...

  15. Biological Control of Nematodes with Bacteria

    Science.gov (United States)

    Biological control of nematodes is receiving increased attention as environmental considerations with the use of nematicides have increased in importance and their high cost prohibits use on many crops. In addition, nematode resistant cultivars are not available for many crops and resistance that i...

  16. A staining method for assessing the viability of Esteya vermicola conidia.

    Science.gov (United States)

    Wang, Yunbo; Thang, NguyenTrong; Li, Zheng; Zhang, Yongan; Li, Jingjie; Xue, Jianjie; Gu, Lijuan; Hong, VuThuy; Mira, Lee; Sung, Changkeun

    2014-07-01

    The viability of conidia of Esteya vermicola, a potentially important biocontrol agent against the pinewood nematode Bursaphelenchus xylophilus, is usually determined by cultivation for 18-48 h in culture medium. As an alternative to this labor-intensive method, we have developed a rapid, simple, and low-cost staining method for assessing E vermicola conidia survival rates. A mixture of neutral red and methylene blue was found to be the most optimal among several stains that also included safranin O and Janus green B. This mixture stained nonviable conidia blue, in contrast to viable conidia, which were stained red in the cytoplasm and blue in the cell wall. This method may be particularly useful for traditional research laboratories, as it provides rapid results using common, relatively inexpensive laboratory equipment.

  17. Mathematical analysis of dynamic spread of Pine Wilt disease.

    Science.gov (United States)

    Dimitrijevic, D D; Bacic, J

    2013-01-01

    Since its detection in Portugal in 1999, the pinewood nematode Bursaphelenchus xylophilus (Steiner and Buhrer), a causal agent of Pine Wilt Disease, represents a threat to European forestry. Significant amount of money has been spent on its monitoring and eradication. This paper presents mathematical analysis of spread of pine wilt disease using a set of partial differential equations with space (longitude and latitude) and time as parameters of estimated spread of disease. This methodology can be used to evaluate risk of various assumed entry points of disease and make defense plans in advance. In case of an already existing outbreak, it can be used to draw optimal line of defense and plan removal of trees. Optimization constraints are economic loss of removal of susceptible trees as well as budgetary constraints of workforce cost.

  18. 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.

  19. Improved nematode extraction from carrot disk culture.

    Science.gov (United States)

    Kaplan, D T; Davis, E L

    1990-07-01

    Radopholus spp. were reared in carrot tissue culture via established procedures, with slight modification. Several plant tissue maceration enzymes and flotation media (salts and sucrose) were evaluated with regard to nematode toxicity and extraction efficiency. Best extraction of viable nematodes and eggs was attained when carrot tissue infested with Radopholus citrophilus or R. similis was macerated with a mixture of 0.50% driselase and 0.50% cellulysin, w/v each, with 2.5 ml of enzyme solution based for each gram of carrot tissue. Maceration slurries containing carrot tissue and nematodes were maintained in open flasks on a rotary shaker (175 rpm) at 26 C for 24 hours. Nematodes and eggs were extracted from resultant culture slurries by flotation with MgSO-7H0 (sp gr 1.1). A protocol is presented to extract large quantities of viable burrowing nematodes and their eggs from carrot disk cultures.

  20. Nondestructive imaging of plant-parasitic nematode development and host response to nematode pathogenesis.

    Science.gov (United States)

    Dinh, Phuong T Y; Knoblauch, Michael; Elling, Axel A

    2014-05-01

    The secluded lifestyle of endoparasitic plant nematodes hampers progress toward a comprehensive understanding of plant-nematode interactions. A novel technique that enables nondestructive, long-term observations of a wide range of live nematodes in planta is presented here. As proof of principle, Pratylenchus penetrans, Heterodera schachtii, and Meloidogyne chitwoodi were labeled fluorescently with PKH26 and used to infect Arabidopsis thaliana grown in microscopy rhizosphere chambers. Nematode behavior, development, and morphology were observed for the full duration of each parasite's life cycle by confocal microscopy for up to 27 days after inoculation. PKH26 accumulated in intestinal lipid droplets and had no negative effect on nematode infectivity. This technique enabled visualization of Meloidogyne gall formation, nematode oogenesis, and nematode morphological features, such as the metacorpus, vulva, spicules, and cuticle. Additionally, microscopy rhizosphere chambers were used to characterize plant organelle dynamics during M. chitwoodi infection. Peroxisome abundance strongly increased in early giant cells but showed a marked decrease at later stages of feeding site development, which suggests a modulation of plant peroxisomes by root-knot nematodes during the infection process. Taken together, this technique facilitates studies aimed at deciphering plant-nematode interactions at the cellular and subcellular level and enables unprecedented insights into nematode behavior in planta.

  1. Genetic analysis of root-knot nematode resistance in potato

    NARCIS (Netherlands)

    Draaistra, J.

    2006-01-01

    The development of potato varieties with resistance towards the potato cyst nematode, allowed a dramatic decrease of the use of nematicides. Subsequently the population of the free living nematodes and the root-knot nematodes ( Meloidogyne spp.) has increased. Among the root-knot nematodes, three Me

  2. A checklist of nematode parasites from Indonesian murids.

    Science.gov (United States)

    Dewi, Kartika; Purwaningsih, Endang

    2013-01-24

    A checklist of nematode parasites from Indonesian murids with their geographic distribution is presented. This checklist is compiled from three sources: the catalogue of nematode parasites of Museum Zoologicum Bogoriense (unpublished specimens in the collection), data from our previous research and articles on nematodes of Indonesian murids. This checklist is presented as a list of nematode parasites with host information, and a host list with information on their nematodes. This paper reports 38 nominal species of nematodes and 13 species identified to the generic level only. The nematodes reported comprise 32 genera and 17 families parasitizing 32 species of Indonesian murids.

  3. A Method for Rapidly Extracting DNA of Bursaphelenchus xylophilus from the Infested Pine Wood for PCR and LAMP Detection%一种适于PCR和LAMP检测的松木中松材线虫DNA快速提取方法

    Institute of Scientific and Technical Information of China (English)

    苟大平; 王曦茁; 汪来发; 田国忠; 朱天辉; 郭民伟

    2015-01-01

    Objective]It is crucial for detection of the pine wood nematode ( PWN) to develop a rapid and economic method of DNA extraction from the infested wood samples by Bursaphelenchus xylophilus. This study aims at developing a method for rapidly extracting DNA of Bursaphelenchus xylophilus from the infested pine wood.[Method]In this study,a new method was developed to directly extract the nematode DNA from the infested wood chips by using Chelex-100 combined with alkaline guanidine thiocyanate. The extracted DNA was amplified by polymerase chain reaction ( PCR) and loop-mediated isothermal amplification ( LAMP) . [Result]The Chelex-100 was used to extract the nematode DNA and the factors, including Chelex-100 concentration, freezing and boiling time, affecting the extraction efficiency were optimized. The result showed that the optimum Chelex-100 final concentration was 1. 5% (W/V),the optimum thawing time was 5 min,and the optimum boiling time was 8 min. The DNA concentration extracted by the Chelex-100 method was significantly higher than that extracted by CTAB and Proteinase K method under the same condition. The ratios of OD260 / 280 of the three methods was in a descending order of CTAB method > Proteinase K ≥Chelex-100 method. The OD260 / 280 value of extraction with Chelex-100 method was significantly lower than that with the CTAB method,but slightly lower than,or equal to that with the Proteinase K method,however the low OD260 / 280 value did not affect the extracted DNA used for PCR amplification. The electrophoresis strip of the specific PCR amplification of the 75 × 32 times dilution of the nematode DNA extracted by Chelex-100 method was still clear. The results of PCR and LAMP indicated that the detection of PWN using the Chelex-100-extracted-DNA was sensitive,specific,and stable. With the method the entire infested wood samples by PWN were detected positive,however,the healthy pine samples,including Pinus thunbergii, P. massoniana,P. tabuliformis and

  4. Multifaceted effects of HZSM-5 (Proton-exchanged Zeolite Socony Mobil-5) on catalytic cracking of pinewood pyrolysis vapor in a two-stage fixed bed reactor.

    Science.gov (United States)

    Wang, Yimeng; Wang, Jie

    2016-08-01

    The pinewood was pyrolyzed in the first reactor at a heating rate of 10°Cmin(-1) from room temperature to 700°C, and the vapor was allowed to be cracked through the second reactor in a temperature range of 450-750°C without and with HZSM-5. Attempts were made to determine a wide spectrum of gaseous and liquid products, as well as the mass and element partitions to gas, water, bio-oil, coke and char. HZSM-5 showed a preferential deoxygenation effect via the facilitated decarbonylation and decarboxylation with the inhibited dehydration at 550-600°C. This catalyst also displayed a high selectivity for the formations of aromatic hydrocarbons and olefins by the promoted hydrogen transfer to these products at 550-600°C. The bio-oil produced with HZSM-5 at 500-600°C had the yields of 14.5-16.8%, the high heat values of 39.1-42.4MJkg(-1), and the energy recoveries of 33-35% (all dry biomass basis).

  5. Parasitic nematodes - from genomes to control.

    Science.gov (United States)

    Mitreva, Makedonka; Zarlenga, Dante S; McCarter, James P; Jasmer, Douglas P

    2007-08-19

    The diseases caused by parasitic nematodes in domestic and companion animals are major factors that decrease production and quality of the agricultural products. Methods available for the control of the parasitic nematode infections are mainly based on chemical treatment, non-chemical management practices, immune modulation and biological control. However, even with integrated pest management that frequently combines these approaches, the effective and long-lasting control strategies are hampered by the persistent exposure of host animals to environmental stages of parasites, the incomplete protective response of the host and acquisition of anthelmintic resistance by an increasing number of parasitic nematodes. Therefore, the challenges to improve control of parasitic nematode infections are multi-fold and no single category of information will meet them all. However, new information, such as nematode genomics, functional genomics and proteomics, can strengthen basic and applied biological research aimed to develop improvements. In this review we will, summarize existing control strategies of nematode infections and discuss ongoing developments in nematode genomics. Genomics approaches offer a growing and fundamental base of information, which when coupled with downstream functional genomics and proteomics can accelerate progress towards developing more efficient and sustainable control programs.

  6. [Nematodes of humans in the Primorye Territory].

    Science.gov (United States)

    Ermolenko, A V; Rumiantseva, E E; Bartkova, A D; Voronok, V M; Poliakova, L F

    2013-01-01

    Nematodes occupy the top in the general pattern of human parasitic diseases in the Primorye Territory. In the south of the Far East, there are a total of 28 nematode species that can parasitize man. However, the authors have identified only 8 nematode-induced diseases, such as ascariasis, enterobiasis, toxocariasis, trichocephaliasis, anisakiasis, trichinosis, dirofilariasis, dioctophymosis. The latter has been found only once in the 1920s. According to official statistical data, the proportion of ascariasis and enterobiasis accounted for 43.8 and 53.5% of the total number of helminthiases, respectively.

  7. 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

  8. 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

  9. Rosmarinic Acid from Eelgrass Shows Nematicidal and Antibacterial Activities against Pine Wood Nematode and Its Carrying Bacteria

    Directory of Open Access Journals (Sweden)

    Qunqun Guo

    2012-11-01

    Full Text Available Pine wilt disease (PWD, a destructive disease for pine trees, is caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus and additional bacteria. In this study, extracts of Zostera marina showed a high nematicidal activity against PWN and some of the bacteria that it carries. Light yellow crystals were obtained from extracts of Z. marina through solvent extraction, followed by chromatography on AB-8 resin and crystallization. The NMR and HPLC analysis showed that the isolated compound was rosmarinic acid (RosA. RosA showed effective nematicidal activity, of which the LC50 (50% lethal concentration to PWN at 24 h, 48 h and 72 h was 1.18 mg/g, 1.05 mg/g and 0.95 mg/g, respectively. To get a high yield rate of RosA from Z. marina, single factor experiments and an L9 (34 orthogonal experiment were performed. This extraction process involved 70% ethanol for 3 h at 40 °C. The extraction dosage was 1:50 (w/v. The highest yield of RosA from Zostera was 3.13 mg/g DW (dried weight. The crude extracts of Zostera marina (10 mg/mL and RosA (1 mg/mL also showed inhibitory effects to some bacterial strains carried by PWN: Klebsiella sp., Stenotrophomonas maltophilia, Streptomyces sp. and Pantoea agglomerans. The results of these studies provide clues for preparing pesticide to control PWD from Z. marina.

  10. RNA interference in plant parasitic nematodes

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... produce effective and durable forms of nematode control. Principle advantages ... Carthew, 1998, 2000) and amphibians (Dirks et al., 2003;. Li and Rohrer .... glands. Cysteine proteinase. Increased male: female ratio. Intestine.

  11. 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

  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. Improved Nematode Extraction from Carrot Disk Culture

    OpenAIRE

    Kaplan, David T.; Davis, Eric L.

    1990-01-01

    Radopholus spp. were reared in carrot tissue culture via established procedures, with slight modification. Several plant tissue maceration enzymes and flotation media (salts and sucrose) were evaluated with regard to nematode toxicity and extraction efficiency. Best extraction of viable nematodes and eggs was attained when carrot tissue infested with Radopholus citrophilus or R. similis was macerated with a mixture of 0.50% driselase and 0.50% cellulysin, w/v each, with 2.5 ml of enzyme solut...

  14. Ascaroside Signaling is Widely Conserved Among Nematodes

    OpenAIRE

    Choe, Andrea; von Reuss, Stephan H.; Kogan, Dima; Robin B Gasser; Platzer, Edward G.; Schroeder, Frank C.; Paul W. Sternberg

    2012-01-01

    Background: Nematodes are among the most successful animals on earth and include important human pathogens, yet little is known about nematode pheromone systems. A group of small molecules called ascarosides has been found to mediate mate finding, aggregation, and developmental diapause in Caenorhabditis elegans, but it is unknown whether ascaroside signaling exists outside of the genus Caenorhabditis. Results: To determine whether ascarosides are used as signaling molecules by other nemat...

  15. 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.

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

    Science.gov (United States)

    Silvestre, A; Cabaret, J

    2004-06-01

    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.

  17. 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.

  18. The screening and identification of the bacterium with nematicidal activity to Bursaphelenchus xylophilus%松材线虫拮抗细菌的筛选和鉴定

    Institute of Scientific and Technical Information of China (English)

    朱丽梅; 吴小芹; 徐旭麟

    2008-01-01

    为了筛选对松材线虫(Bursaphelenchus xylophilus)具有较高杀线活性的拮抗细菌,从马尾松林中分离获得了230株细菌,并从中筛选出8株对松材线虫具有较高杀线活性的细菌,其中JK-JS3菌株对松材线虫的杀线活性最高.将该细菌培养滤液分别稀释2倍、4倍、10倍处理松材线虫,72h后线虫的死亡率均达到100%;线虫死亡后虫体消解,消解率分别为100%、97.8%、96.4%.测定了该细菌培养滤液对香蕉穿孔线虫(Radopholus similis)和水稻干尖线虫(Aphelenchoides besseyi)等植物线虫的杀线活性,结果表明对不同种的线虫杀线活性有差异.该菌株培养滤液对松材线虫和小杆线虫(Rhabditis sp.)的杀线活性最高,其余杀线活性从高到低依次为拟松材线虫(Bursaphelenchus mucronatus)、腐生线虫(Panagrellus redivivus)、香蕉穿孔线虫和水稻干尖线虫.形态特征和革兰氏染色观察,该细菌为革兰氏阳性菌、产芽孢、具有周生鞭毛;经Biolog细菌鉴定仪进一步鉴定该细菌为解淀粉芽孢杆菌(Bacillus amyloliquefaciens).

  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. Influence of Metalaxyl on Three Nematodes of Citrus

    Science.gov (United States)

    Kaplan, David T.

    1983-01-01

    Metalaxyl significantly reduced population of Pratylenchus coffeae, Radopholus similis, and Tylenchulus semipenetrans in roots of Citrus limon (rough lemon) under greenhouse conditions. Postinoculation treatment of rough lemon seedlings was not as effective i n reducing nematode populations as was treatment before inoculation. Fewer nematodes infected metalaxyl-treated roots than nontreated roots. However, incubation of nematodes in metalaxyl did not inhibit nematode motility or their ability to locate and infect roots. Cellular responses to nematode injection differed between treated and nontreated tissues. Metalaxyl appeared to confer nematode contraol by modifying citrus roots such that a normally susceptible rootstock became tolerant. PMID:19295833

  1. Pesticide toxicity and selection for the pine wood nematode%杀灭松材线虫的高效药物筛选与毒性测定

    Institute of Scientific and Technical Information of China (English)

    来燕学; 池树友; 王亚红; 张毅丰; 韩正敏

    2011-01-01

    为筛选出对松材线虫Bursaphelenchus xylophius具有高效快速杀灭作用的药物,采用线虫悬浮液+农药的直接触杀法,选择了22种药物处理松材线虫1 h,测定了对松材线虫的半致死浓度(LC50).结果表明:不同药物对松材线虫表现出不同的杀灭作用,供试的22种药物中,甲基阿维菌素(甲维盐)杀灭效果最好,1 h半致死浓度仅为03 mg·L-1;杀螟丹效果最差,1 h半致死浓度达21 053 mg·L-1.另外,苦参碱、抑太保、溴氰菊酯和阿维菌素等4种药物对松材线虫具有很强的毒杀作用,其1 h半致死浓度分别为1.2,2.5,4.2和4.5 mg·L-1.甲维盐和阿维菌素能高效快速杀灭松材线虫;这些对松材线虫高效敏感药物的筛选成功,为开发树干注射剂防治松材线虫病提供了基础.%To determine highly toxic and fast-acting pesticides to combat the pine wood nematode (Bursaphelenchus xylophilus), a toxicity test of 22 kinds of pesticide used against the pine wood nematode (PWN) was conducted using a PWN suspension liquid plus pesticide with a processing time of 1 h to determine a median lethal concentration (LC50) for each pesticide.Results showed that the LC50 after a 1 h treatment was best with emamectin (0.3 mg·L-1) and worst with cartap (21.053 g·L-1).In addition, four kinds of pesticide revealed acute activity toward the pine wood nematode with an LC50 after 1 h treatment of: matrin (1.2 mg·L-1), chlorfluazuron (2.5 mg·L-1), deltamethrin (4.2 mg·L-1), and abamectin (4.5 mg·L-1).This meant that emamectin and abamectin could quickly and efficiently kill PWN, and the selected pesticides with acute activity to PWN could be used to develop a trunk injection against pine wilt disease.

  2. 美国松材线虫体表携带优势细菌的鉴定及致病性%Identification and pathogenicity of bacterial strains carried by American pine wood nematodes

    Institute of Scientific and Technical Information of China (English)

    曾腓力; 贲爱玲; 郑敬荣; 韩正敏

    2012-01-01

    为证实松材线虫Bursaphelenchus xylophilus虫株携带弱毒细菌替代强毒株系防治松树萎蔫病这一思路的可行性,从2个美国松材线虫虫株体表分离并确定了优势细菌,测定了各优势细菌的毒性和致病性,并对这些菌株进行了初步鉴定.细菌分离结果显示:MG4,MG5,MG8和MG9等4菌株为美国线虫体表的优势菌株.毒力测试表明,与中国松材线虫携带的强致病菌相比,美国松材线虫携带的4个菌株的产毒能力和致病性均较低,可以作为生防细菌的候选菌株使用.经细菌的常规染色、形态学观察及16S rDNA序列分析,MG4,MG5,MG8和MG9菌株分别被鉴定为代夫特菌 Delftia tsuruhatensis,恶臭假单胞菌 Pseudomonas putida,嗜麦芽窄食单胞菌Stenotrophomonas maltophilia和泛菌属1种Pantoea sp..%To confirm that pine wood nematodes carrying attenuated bacterial strains could alleviate pine wilt disease, bacteria were isolated from two nematodes native to America. Bacterial virulence and pathogenicity were tested with pine seedlings, and preliminary identification of predominant strains was determined using bacterial staining reactions and morphology combined with 16S rDNA sequence analysis. Results of the isolation experiment showed that the predominant bacteria which American nematodes carried were strains MG4 (Delftia tsuruhatensis), MG5 (Pseudomonas putida), MG8 (Stenotrophomonas maltophilia), and MG9 (Pan-toea sp.) Virulence and pathogenicity results demonstrated that compared with the high virulent bacteria strains (Pseudomonas fluorescence) isolated from Chinese nematodes, toxicity and pathogenicity of bacterial strains from America were relatively low. Thus, the bacteria carried by American nematodes should be considered the candidates for biological control agents.

  3. Interspecific nematode signals regulate dispersal behavior.

    Directory of Open Access Journals (Sweden)

    Fatma Kaplan

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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.

  4. Two new species of soil nematodes from Manipur, India.

    Science.gov (United States)

    Chanu, Loukrakpam Bina; Meitei, N Mohilal; Shah, M Manjur

    2016-09-01

    Survey for soil nematodes associated with mulberry plants in valley districts of Manipur revealed the presence of two new species of soil nematodes of the genus Tylenchus sp. and Telotylenchus sp. The two new species are described and illustrated here.

  5. Study on Strategies for Upgrading the Biological Control Belt of Pinewood Nematode Disease round the Yellow Mountains%升级改造环黄山松材线虫病生物防控带对策研究

    Institute of Scientific and Technical Information of China (English)

    谢双鸽

    2015-01-01

    This paper explored the upgrading construction of the biological control belt round the scenic areas of the Yellow Mountains in its prevention system against the disease and analyzed the disease prevention actualities and actually existing problems. Some specific measures were put forward for upgrading the biological control belt round the Yellow Mountains and the expected Outcomes and benefits of the control belt after upgrading were comprehensively elaborated.%本文对黄山松材线虫病预防体系中环黄山风景区生物控制带的升级改造建设进行了探究,就黄山市预防松材线虫病现状、现实存在的问题,对环黄山生物控制带升级改造具体措施和改造后生物控制带预期达到效益等方面进行了综合阐述.

  6. Nematode feeding sites: unique organs in plant roots.

    Science.gov (United States)

    Kyndt, Tina; Vieira, Paulo; Gheysen, Godelieve; de Almeida-Engler, Janice

    2013-11-01

    Although generally unnoticed, nearly all crop plants have one or more species of nematodes that feed on their roots, frequently causing tremendous yield losses. The group of sedentary nematodes, which are among the most damaging plant-parasitic nematodes, cause the formation of special organs called nematode feeding sites (NFS) in the root tissue. In this review we discuss key metabolic and cellular changes correlated with NFS development, and similarities and discrepancies between different types of NFS are highlighted.

  7. 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....

  8. [Research Progress on Genetic Diversity in Animal Parasitic Nematodes].

    Science.gov (United States)

    YIN, Fang-yuan; LI, Fa-cai; ZHAO, Jun-long; HU, Min

    2015-10-01

    The development of molecular genetic markers for parasitic nematodes has significant implications in fundamental and applied research in Veterinary Parasitology. Knowledge on genetic diversity of nematodes would not only provide a theoretical basis for understanding the spread of drug-resistance alleles, but also have implications in the development of nematode control strategies. This review discusses the applications of molecular genetic markers (RFLP, RAPD, PCR-SSCP, AFLP, SSR and mitochondrial DNA) in research on the genetic diversity of parasitic nematodes.

  9. 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.

  10. Biocontrol: the potential of entomophilic nematodes in insect management.

    Science.gov (United States)

    Webster, J M

    1980-10-01

    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.

  11. 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.

  12. Characterization of biocontrol traits in the entomopathogenic nematode Heterorhabditis georgiana (Kesah strain), and phylogenetic analysis of the nematode's symbiotic bacteria.

    Science.gov (United States)

    Our objective was to estimate the biocontrol potential of the recently discovered entomopathogenic nematode species, Heterorhabditis georgiana (Kesha strain). Virulence and environmental tolerance were tested among several nematode species. Heterorhabditis georgiana expressed low or intermediate c...

  13. 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 cyclin

  14. 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 nematode secretions in feeding

  15. A novel flavivirus in the soybean cyst nematode

    Science.gov (United States)

    Heterodera glycines, the soybean cyst nematode (SCN) is a subterranean root pathogen that causes the most damaging disease of soybean in the United States. A novel nematode virus genome, soybean cyst nematode virus 5 (SbCNV5), was identified in RNASeq data from SCN eggs and second-stage juveniles. T...

  16. 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

  17. ENDOPARASITIC NEMATODES OF THE GENUS PRATYLENCHUS ON SOYBEAN

    OpenAIRE

    Ivana Majić

    2010-01-01

    The aims of the study were to determine susceptibility of soybean cultivars to root lesion nematodes (genus Pratylenchus), effect of intensity of arbuscular mycorrhizal fungi (AMF) colonization on penetration of endoparasitic nematodes in soybean roots, and trophic biodiversity of nematode community in soybean. In the period 2005 - 2007, investigations were conducted at experimental sites of Agricultural Institute Osijek. Seven soybean cultivars were included (Korana, ...

  18. Site-Specific Detection and Management of Nematodes

    Science.gov (United States)

    Nematode distribution varies significantly throughout a field and is highly correlated to soil texture and other edaphic factors. Field-wide application results in nematicides being applied to areas without nematodes and the application of sub-effective levels in areas with high nematode densities. ...

  19. 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.

  20. Nematode problems affecting agriculture in the Philippines.

    Science.gov (United States)

    Davide, R G

    1988-04-01

    Nematodes are considered major pests on most economic crops in the Philippines, particularly on banana, pineapple, citrus, tomato, ramie, and sugarcane. Radopholus similis is the most destructive nematode on banana, while Meloidogyne spp. are more serious on various vegetable crops such as tomato, okra, and celery and on fiber crops such as ramie. Tylenchulus semipenetrans is a problem on citrus and Rotylenchulus reniformis on pineapple and some legume crops. Hirschmanniella oryzae and Aphelenchoides besseyi are becoming serious on rice, and Pratylenchus zeae is affecting corn in some areas. Lately, Globodera rostochiensis has been causing serious damage on potato in the highlands. Control measures such as crop rotation, planting resistant varieties, chemical nematicide application, and biological control have been recommended to control these nematodes.

  1. 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.

  2. ENDOPARASITIC NEMATODES OF THE GENUS PRATYLENCHUS ON SOYBEAN

    Directory of Open Access Journals (Sweden)

    Ivana Majić

    2010-12-01

    Full Text Available The aims of the study were to determine susceptibility of soybean cultivars to root lesion nematodes (genus Pratylenchus, effect of intensity of arbuscular mycorrhizal fungi (AMF colonization on penetration of endoparasitic nematodes in soybean roots, and trophic biodiversity of nematode community in soybean. In the period 2005 - 2007, investigations were conducted at experimental sites of Agricultural Institute Osijek. Seven soybean cultivars were included (Korana, Kuna, Anica, Una, Ika, Podravka 95 i Tisa. Soil and roots were sampled during four soybean growth stages. Nematode populations from soil and root samples were determined as well as reproductive index (RI of root lesion nematode population, and intensity of AMF root colonization. Ten ecological indexes were calculated in order to determine trophic biodiversity of nematode community: H’, λ, N1, N2, E1, E2, PPI, NCR, F/B, B+F/BP. Two Pratylenchus species were determined from the soil samples: P. thornei Sher & Allen 1953 and P. scribneri Steiner 1943. The results indicate negative effect of Pratylenchus spp. (extracted from soil samples on soybean yields for all but one cultivar (Una. However, increase in root lesion nematode population did not lead to linear decrease in plant biomass. Cultivars Ika, Podravka 95, Tisa and Una proved to be the best hosts to root lesion nematodes since these cultivars statistically differed among cultivars for the highest density of root lesion nematodes. Cultivar Una showed the least susceptibility to root lesion nematodes since it had the lowest RI and negative effects on yields were not determined. Due to high RI values and negative effect on soybean yields. Population densities of root lesion nematodes from soil samples, (compared to nematodes detected in roots are more reliable indicator of root lesion nematodes damaging potential. Since values of RI for Pratylenchus spp. in soil samples were determined as very high and soybean yields were

  3. Transformation of wetlands in the NE part of the Tuchola Pinewoods over the last 200 years on the basis of cartographic materials

    Science.gov (United States)

    Tyszkowski, Sebastian; Kaczmarek, Halina

    2015-04-01

    Transformation of wetlands is conditioned by climatic, geological, hydrological and biotic as well as anthropogenic factors. Dynamic changes in lake and river systems in Northern Poland occurred at the time of the dead ice blocks melting and permafrost decay. Over the following periods of time, these changes tended to be more evolutionary. The disappearance of lakes and formation of wetlands occurred in the process of slow shallowing by filling lake basins with biogenic sediments. Only in the last few hundred years the process has been disturbed and significantly remodelled by human activity. A particularly important role was played by reclamation which led to the drainage of many wetlands and disappearance of lakes. Draining of wetlands has led to an increase in the participation of birch, oak, maple and hornbeam in the stands which in turn might have lead to a change in sedimentation in water bodies. Furthermore, due to mineralisation of peat some micro- and macroelements have become available to plants and incorporated back into circulation in the ecosystem. The goal of the research is to determine the direction and rate of change of wetlands over the last 200 years in the selected test area around Lake Czechowskie in the Tuchola Pinewoods. The study area is located in northern Poland, within the Weichselian glaciation. From earlier studies it is known that in this area over the last 200 years the biggest changes resulted from massive tree felling between the end of the eighteenth century and mid-nineteenth century. At the same time since the mid-eighteenth century, in this area very intensive reclamation works were carried out whose main objective was to convert peatlands into meadows. The biggest changes caused by land reclamation took place between mid-nineteenth and early twentieth century. At the same time, this area was abundant in dams and water mills. This study is based on historical and contemporary maps, including the following: Schr

  4. Climate-landform effects on lateglacial vegetation pattern in northeastern Tuchola Pinewoods (northern Poland): multiproxy evidence from the Lake Czechowskie catchment, northern Poland.

    Science.gov (United States)

    Noryśkiewicz, Agnieszka M.; Kordowski, Jarosław; Tyszkowski, Sebastian; Kramkowski, Mateusz; Zawiska, Izabela; Rzodkiewicz, Monika; Mirosław-Grabowska, Joanna; Ott, Florian; Słowiński, Michał; Obremska, Milena; Błaszkiewicz, Mirosław; Brauer, Achim

    2016-04-01

    The study area is located in northern Poland in the northeastern part of Tuchola Pinewoods in a young glacially formed and diversified landscape. It comprises the entire lake catchment of Lake Czechowskie (19.76 km2), which comprises a second lake upstream as well as a palaeolake (Trzechowskie) located between the two present-day lakes. Biogenic sediments from eight cores were studied by multiproxy analyses to reconstruct the environmental changes and climate signals during the last Late Glacial and early Holocene. The cores were collected along a W-E transect from Głęboczek Lake to the Czechowskie Lake and were located in different topographic positions (deepest and shallow part of the lake, old lake-bed plains and paleolakes) with a maximum distance of 2.2 km. Detailed and high resolution analyses (pollen, diatoms, cladocera, stable isotopes, geochemistry, varve chronology and radiocarbon dating) to identify the main stages in the development of the natural environment were made. Palynological data indicate melting of the buried ice blocks and the following the onset of biogenic lacustrine sedimentation. The general pattern of vegetation changes in all profiles is similar and includes Late Glacial steppe-tundra plant communities at the onset of organic lake sedimentation. The palynological record of the most profiles shows a high participation of seabuckthorn (Hippophae) in the initial stadium of vegetation history. The lack of this succession in the most western core (Głęboczek Lake) indicates a later period of melt-out processes of the buried dead-ice blocks in the Głęboczek Lake basin. The thickness and type of the accumulated sediments differ significantly during the Bolling-Alerod complex and Younger Dryas Period between our sites. These differences are also reflected in variations of plant species among the different sites. The comparison of different profiles within one catchment allows us to distinguish site specific local responses to climate

  5. [Nematode parasites of birds of the fauna in Tunisia].

    Science.gov (United States)

    Bernard, J

    1989-01-01

    330 birds of Tunisia were necropsied; they belong to 73 species among 29 families and 13 orders. We so collect 36 species of nematodes from 9 families. The relative importance of these is variable. The best represented are: Capillariidae (6 species), Spiruridae (6 species), Acuariidae (9 species) and Filariidae (6 species). The parasitism by nematodes is not uniform. Among the 330 birds autopsied only 51 were parasited by nematodes (15.45%) among 25 of the examined birds species (34.2%). Among these 25, sixteen (64%) presented only one species of parasitic nematode, six (24%) arboured two, (8%) three and only one, (partridges) presents six species of nematodes.

  6. Cuticle surface coat of plant-parasitic nematodes.

    Science.gov (United States)

    Davies, Keith G; Curtis, Rosane H C

    2011-01-01

    The surface coat (SC) of the plant-parasitic nematode cuticle is an understudied area of current research, even though it likely plays key roles in both nematode-plant and nematode-microbe interactions. Although in several ways Caenorhabditis elegans is a poor model for plant-parasitic nematodes, it is a useful starting point for investigations of the cuticle and its SC, especially in the light of recent work using this species as a model for innate immunity and the generic biology underpinning much host-parasite biology. We review the research focused on the involvement of the SC of plant-parasitic nematodes. Using the insights gained from animal-parasitic nematodes and other sequenced nematodes, we discuss the key roles that the SC may play. Copyright © 2011 by Annual Reviews. All rights reserved.

  7. 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.

  8. Cell cycle activation by plant parasitic nematodes

    NARCIS (Netherlands)

    Goverse, A.; Almeida Engler, de J.; Verhees, J.; Krol, van der S.; Helder, J.; Gheysen, G.

    2000-01-01

    Sedentary nematodes are important pests of crop plants. They are biotrophic parasites that can induce the (re)differentiation of either differentiated or undifferentiated plant cells into specialized feeding cells. This (re)differentiation includes the reactivation of the cell cycle in specific

  9. 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...

  10. Cell cycle activation by plant parasitic nematodes

    NARCIS (Netherlands)

    Goverse, A.; Almeida Engler, de J.; Verhees, J.; Krol, van der S.; Helder, J.; Gheysen, G.

    2000-01-01

    Sedentary nematodes are important pests of crop plants. They are biotrophic parasites that can induce the (re)differentiation of either differentiated or undifferentiated plant cells into specialized feeding cells. This (re)differentiation includes the reactivation of the cell cycle in specific plan

  11. Mermithid Nematodes: In Vitro Culture Attempts

    OpenAIRE

    Finney, Jean R.

    1981-01-01

    Few attempts at in vitro culture of mermithids have been undertaken. The various methods used to initiate cultures are described. The capacity of a range of media to promote growth and development of the nematodes has been evaluated and current approaches to in vitro outlined.

  12. Focus on molecular plant-nematode interactions

    NARCIS (Netherlands)

    Hogenhout, S.; Mitchum, M.; Smant, G.

    2013-01-01

    Sedentary plant-parasitic nematodes engage in a long-lasting and intimate relationship with their host plant. This interaction starts in the soil when freshly hatched infective juveniles are attracted to specific parts of a host plant root system. Little is known of what determines the attractivenes

  13. 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…

  14. 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...

  15. 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

  16. Diverse CLE peptides from cyst nematode species

    Science.gov (United States)

    Plant CLAVATA3/ESR (CLE)-like peptides play diverse roles in plant growth and development including maintenance of the stem cell population in the root meristem. Small secreted peptides sharing similarity to plant CLE signaling peptides have been isolated from several cyst nematode species including...

  17. Growing Tomato (Lycopersicon esculentum L.) in Nematode ...

    African Journals Online (AJOL)

    Infested Soil and the Pest Implications in Poorly Managed. Post-harvested Fields ... In this study, the effect of Procarvian carpensis manure at a rate of 5tons/ha and the balanced ... nematode in Tabora environmental condition. Furthermore ...

  18. Evolution of embryonic development in nematodes

    Directory of Open Access Journals (Sweden)

    Schulze Jens

    2011-09-01

    Full Text Available Abstract Background Nematodes can be subdivided into basal Enoplea (clades 1 and 2 and more derived Chromadorea (clades 3 to 12. Embryogenesis of Caenorhabditis elegans (clade 9 has been analyzed in most detail. Their establishment of polarity and asymmetric cleavage requires the differential localization of PAR proteins. Earlier studies on selected other nematodes revealed that embryonic development of nematodes is more diverse than the essentially invariant development of C. elegans and the classic study object Ascaris had suggested. To obtain a more detailed picture of variations and evolutionary trends we compared embryonic cell lineages and pattern formation in embryos of all 12 nematode clades. Methods The study was conducted using 4-D microscopy and 3-D modeling of developing embryos. Results We found dramatic differences compared to C. elegans in Enoplea but also considerable variations among Chromadorea. We discovered 'Polarity Organizing Centers' (POCs that orient cleavage spindles along the anterior-posterior axis in distinct cells over consecutive cell generations. The resulting lineally arranged blastomeres represent a starting point for the establishment of bilateral symmetry within individual lineages. We can discern six different early cleavage types and suggest that these variations are due to modifications in the activity of the POCs in conjunction with changes in the distribution of PAR proteins. In addition, our studies indicate that lineage complexity advanced considerably during evolution, that is we observe trends towards an increase of somatic founder cells, from monoclonal to polyclonal lineages and from a variable (position-dependent to an invariable (lineage-dependent way of cell fate specification. In contrast to the early phase of embryogenesis, the second half ('morphogenesis' appears similar in all studied nematodes. Comparison of early cleavage between the basal nematode Tobrilus stefanskii and the tardigrade

  19. Parasitic Nematode Immunomodulatory Strategies: Recent Advances and Perspectives.

    Science.gov (United States)

    Cooper, Dustin; Eleftherianos, Ioannis

    2016-09-14

    More than half of the described species of the phylum Nematoda are considered parasitic, making them one of the most successful groups of parasites. Nematodes are capable of inhabiting a wide variety of niches. A vast array of vertebrate animals, insects, and plants are all identified as potential hosts for nematode parasitization. To invade these hosts successfully, parasitic nematodes must be able to protect themselves from the efficiency and potency of the host immune system. Innate immunity comprises the first wave of the host immune response, and in vertebrate animals it leads to the induction of the adaptive immune response. Nematodes have evolved elegant strategies that allow them to evade, suppress, or modulate host immune responses in order to persist and spread in the host. Nematode immunomodulation involves the secretion of molecules that are capable of suppressing various aspects of the host immune response in order to promote nematode invasion. Immunomodulatory mechanisms can be identified in parasitic nematodes infecting insects, plants, and mammals and vary greatly in the specific tactics by which the parasites modify the host immune response. Nematode-derived immunomodulatory effects have also been shown to affect, negatively or positively, the outcome of some concurrent diseases suffered by the host. Understanding nematode immunomodulatory actions will potentially reveal novel targets that will in turn lead to the development of effective means for the control of destructive nematode parasites.

  20. Parasitic Nematode Immunomodulatory Strategies: Recent Advances and Perspectives

    Science.gov (United States)

    Cooper, Dustin; Eleftherianos, Ioannis

    2016-01-01

    More than half of the described species of the phylum Nematoda are considered parasitic, making them one of the most successful groups of parasites. Nematodes are capable of inhabiting a wide variety of niches. A vast array of vertebrate animals, insects, and plants are all identified as potential hosts for nematode parasitization. To invade these hosts successfully, parasitic nematodes must be able to protect themselves from the efficiency and potency of the host immune system. Innate immunity comprises the first wave of the host immune response, and in vertebrate animals it leads to the induction of the adaptive immune response. Nematodes have evolved elegant strategies that allow them to evade, suppress, or modulate host immune responses in order to persist and spread in the host. Nematode immunomodulation involves the secretion of molecules that are capable of suppressing various aspects of the host immune response in order to promote nematode invasion. Immunomodulatory mechanisms can be identified in parasitic nematodes infecting insects, plants, and mammals and vary greatly in the specific tactics by which the parasites modify the host immune response. Nematode-derived immunomodulatory effects have also been shown to affect, negatively or positively, the outcome of some concurrent diseases suffered by the host. Understanding nematode immunomodulatory actions will potentially reveal novel targets that will in turn lead to the development of effective means for the control of destructive nematode parasites. PMID:27649248

  1. Parasitic Nematode Immunomodulatory Strategies: Recent Advances and Perspectives

    Directory of Open Access Journals (Sweden)

    Dustin Cooper

    2016-09-01

    Full Text Available More than half of the described species of the phylum Nematoda are considered parasitic, making them one of the most successful groups of parasites. Nematodes are capable of inhabiting a wide variety of niches. A vast array of vertebrate animals, insects, and plants are all identified as potential hosts for nematode parasitization. To invade these hosts successfully, parasitic nematodes must be able to protect themselves from the efficiency and potency of the host immune system. Innate immunity comprises the first wave of the host immune response, and in vertebrate animals it leads to the induction of the adaptive immune response. Nematodes have evolved elegant strategies that allow them to evade, suppress, or modulate host immune responses in order to persist and spread in the host. Nematode immunomodulation involves the secretion of molecules that are capable of suppressing various aspects of the host immune response in order to promote nematode invasion. Immunomodulatory mechanisms can be identified in parasitic nematodes infecting insects, plants, and mammals and vary greatly in the specific tactics by which the parasites modify the host immune response. Nematode-derived immunomodulatory effects have also been shown to affect, negatively or positively, the outcome of some concurrent diseases suffered by the host. Understanding nematode immunomodulatory actions will potentially reveal novel targets that will in turn lead to the development of effective means for the control of destructive nematode parasites.

  2. Loss of the insulator protein CTCF during nematode evolution

    Directory of Open Access Journals (Sweden)

    Schierenberg Einhard

    2009-08-01

    Full Text Available Abstract Background The zinc finger (ZF protein CTCF (CCCTC-binding factor is highly conserved in Drosophila and vertebrates where it has been shown to mediate chromatin insulation at a genomewide level. A mode of genetic regulation that involves insulators and insulator binding proteins to establish independent transcriptional units is currently not known in nematodes including Caenorhabditis elegans. We therefore searched in nematodes for orthologs of proteins that are involved in chromatin insulation. Results While orthologs for other insulator proteins were absent in all 35 analysed nematode species, we find orthologs of CTCF in a subset of nematodes. As an example for these we cloned the Trichinella spiralis CTCF-like gene and revealed a genomic structure very similar to the Drosophila counterpart. To investigate the pattern of CTCF occurrence in nematodes, we performed phylogenetic analysis with the ZF protein sets of completely sequenced nematodes. We show that three ZF proteins from three basal nematodes cluster together with known CTCF proteins whereas no zinc finger protein of C. elegans and other derived nematodes does so. Conclusion Our findings show that CTCF and possibly chromatin insulation are present in basal nematodes. We suggest that the insulator protein CTCF has been secondarily lost in derived nematodes like C. elegans. We propose a switch in the regulation of gene expression during nematode evolution, from the common vertebrate and insect type involving distantly acting regulatory elements and chromatin insulation to a so far poorly characterised mode present in more derived nematodes. Here, all or some of these components are missing. Instead operons, polycistronic transcriptional units common in derived nematodes, seemingly adopted their function.

  3. 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.

  4. RNAi and functional genomics in plant parasitic nematodes.

    Science.gov (United States)

    Rosso, M N; Jones, J T; Abad, P

    2009-01-01

    Plant nematology is currently undergoing a revolution with the availability of the first genome sequences as well as comprehensive expressed sequence tag (EST) libraries from a range of nematode species. Several strategies are being used to exploit this wealth of information. Comparative genomics is being used to explore the acquisition of novel genes associated with parasitic lifestyles. Functional analyses of nematode genes are moving toward larger scale studies including global transcriptome profiling. RNA interference (RNAi) has been shown to reduce expression of a range of plant parasitic nematode genes and is a powerful tool for functional analysis of nematode genes. RNAi-mediated suppression of genes essential for nematode development, survival, or parasitism is revealing new targets for nematode control. Plant nematology in the genomics era is now facing the challenge to develop RNAi screens adequate for high-throughput functional analyses.

  5. Rolling circle amplification of complete nematode mitochondrial genomes.

    Science.gov (United States)

    Tang, Sha; Hyman, Bradley C

    2005-06-01

    To enable investigation of nematode mitochondrial DNA evolution, methodology has been developed to amplify intact nematode mitochondrial genomes in preparative yields using a rolling circle replication strategy. Successful reactions were generated from whole cell template DNA prepared by alkaline lysis of the rhabditid nematode Caenorhabditis elegans and a mermithid nematode, Thaumamermis cosgrovei. These taxa, representing the two major nematode classes Chromodorea and Enoplea, maintain mitochondrial genomes of 13.8 kb and 20.0 kb, respectively. Efficient amplifications were conducted on template DNA isolated from individual or pooled nematodes that were alive or stored at -80 degrees C. Unexpectedly, these experiments revealed that multiple T. cosgrovei mitochondrial DNA haplotypes are maintained in our local population. Rolling circle amplification products can be used as templates for standard PCR reactions with specific primers that target mitochondrial genes or for direct DNA sequencing.

  6. Immunity to gastrointestinal nematodes: mechanisms and myths.

    Science.gov (United States)

    Grencis, Richard K; Humphreys, Neil E; Bancroft, Allison J

    2014-07-01

    Immune responses to gastrointestinal nematodes have been studied extensively for over 80 years and intensively investigated over the last 30-40 years. The use of laboratory models has led to the discovery of new mechanisms of protective immunity and made major contributions to our fundamental understanding of both innate and adaptive responses. In addition to host protection, it is clear that immunoregulatory processes are common in infected individuals and resistance often operates alongside modulation of immunity. This review aims to discuss the recent discoveries in both host protection and immunoregulation against gastrointestinal nematodes, placing the data in context of the specific life cycles imposed by the different parasites studied and the future challenges of considering the mucosal/immune axis to encompass host, parasite, and microbiome in its widest sense.

  7. Mucocutaneous manifestations of helminth infections: Nematodes.

    Science.gov (United States)

    Lupi, Omar; Downing, Christopher; Lee, Michael; Pino, Livia; Bravo, Francisco; Giglio, Patricia; Sethi, Aisha; Klaus, Sidney; Sangueza, Omar P; Fuller, Claire; Mendoza, Natalia; Ladizinski, Barry; Woc-Colburn, Laila; Tyring, Stephen K

    2015-12-01

    In the 21st century, despite increased globalization through international travel for business, medical volunteerism, pleasure, and immigration/refugees into the United States, there is little published in the dermatology literature regarding the cutaneous manifestations of helminth infections. Approximately 17% of travelers seek medical care because of cutaneous disorders, many related to infectious etiologies. This review will focus on the cutaneous manifestations of helminth infections and is divided into 2 parts: part I focuses on nematode infections, and part II focuses on trematode and cestode infections. This review highlights the clinical manifestations, transmission, diagnosis, and treatment of helminth infections. Nematodes are roundworms that cause diseases with cutaneous manifestations, such as cutaneous larval migrans, onchocerciasis, filariasis, gnathostomiasis, loiasis, dracunculiasis, strongyloidiasis, ascariasis, streptocerciasis, dirofilariasis, and trichinosis. Tremadotes, also known as flukes, cause schistosomiasis, paragonimiasis, and fascioliasis. Cestodes (tapeworms) are flat, hermaphroditic parasites that cause diseases such as sparganosis, cysticercosis, and echinococcus.

  8. Computational and phylogenetic validation of nematode horizontal gene transfer

    OpenAIRE

    Bird David; Scholl Elizabeth H

    2011-01-01

    Abstract Sequencing of expressed genes has shown that nematodes, particularly the plant-parasitic nematodes, have genes purportedly acquired from other kingdoms by horizontal gene transfer. The prevailing orthodoxy is that such transfer has been a driving force in the evolution of niche specificity, and a recent paper in BMC Evolutionary Biology that presents a detailed phylogenetic analysis of cellulase genes in the free-living nematode Pristionchus pacificus at the species, genus and family...

  9. Intraocular nematode with diffuse unilateral subacute neuroretinitis: case report

    OpenAIRE

    Zakariah Sakinah; Said Mariyani; Alwi Azma-Azalina; Yusoff Munira,; Ghani Zulkifli; Zunaina Embong

    2011-01-01

    Abstract Background Live intraocular nematode is a rare occurrence. Nematode can migrate actively within the eye, creating visual symptoms and damaging ocular tissue. Case presentation A 26-year old man presented with painless reduced vision of the left eye for one week duration. It was associated with floaters. Visual acuity on the left eye was hand movement. Anterior segment examination was normal with normal intra-ocular pressure. Fundus examination showed a live nematode lying subretinall...

  10. Conserved nematode signalling molecules elicit plant defenses and pathogen resistance

    OpenAIRE

    Manosalva, P; Manohar, M; von Reuss, S.; Chen, S.; Koch, A; Kaplan, F; Choe, A.; Micikas, R.; X. Wang; Kogel, K.; Sternberg, P.; Williamson, V; Schroeder, D; Klessig, F.

    2015-01-01

    Plant-defense responses are triggered by perception of conserved microbe-associated molecular patterns (MAMPs), for example, flagellin or peptidoglycan. However, it remained unknown whether plants can detect conserved molecular patterns derived from plant-parasitic animals, including nematodes. Here we show that several genera of plant-parasitic nematodes produce small molecules called ascarosides, an evolutionarily conserved family of nematode pheromones. Picomolar to micromolar concentratio...

  11. Metal stress in free-living nematodes

    OpenAIRE

    Hamelijnck-Arts, M.S.J.

    2001-01-01

    Terrestrial invertebrates offer meaningful targets for assessing the potential adverse effects of chemicals on soil ecosystems. Invertebrates play a major role in the functioning of the soil ecosystem by enhancing the soil structure, mineralization and the decomposition of organic material, and because of their role in the foodweb. The most dominant group of terrestrial invertebrates, in fact of all multicellular organisms on earth, are nematodes, also called threadworms or roundworms. Nemato...

  12. Bacillus thuringiensis crystal proteins that target nematodes

    OpenAIRE

    Wei, Jun-Zhi; Hale, Kristina; Carta, Lynn; Platzer, Edward; Wong, Cynthie; Fang, Su-Chiung; Aroian, Raffi V.

    2003-01-01

    Bacillus thuringiensis (Bt) crystal proteins are pore-forming toxins used as insecticides around the world. Previously, the extent to which these proteins might also target the invertebrate phylum Nematoda has been mostly ignored. We have expressed seven different crystal toxin proteins from two largely unstudied Bt crystal protein subfamilies. By assaying their toxicity on diverse free-living nematode species, we demonstrate that four of these crystal proteins are active against multiple nem...

  13. Assaying environmental nickel toxicity using model nematodes.

    Science.gov (United States)

    Rudel, David; Douglas, Chandler D; Huffnagle, Ian M; 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. 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.

  14. 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.

  15. 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.

  16. Acetylcholinesterase genes in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Combes, D; Fedon, Y; Toutant, J P; Arpagaus, M

    2001-01-01

    Acetylcholinesterase (AChE, EC 3.1.1.7) is responsible for the termination of cholinergic nerve transmission. It is the target of organophosphates and carbamates, two types of chemical pesticides being used extensively in agriculture and veterinary medicine against insects and nematodes. Whereas there is usually one single gene encoding AChE in insects, nematodes are one of the rare phyla where multiple ace genes have been unambiguously identified. We have taken advantage of the nematode Caenorhabditis elegans model to identify the four genes encoding AChE in this species. Two genes, ace-1 and ace-2, encode two major AChEs with different pharmacological properties and tissue repartition: ace-1 is expressed in muscle cells and a few neurons, whereas ace-2 is mainly expressed in motoneurons. ace-3 represents a minor proportion of the total AChE activity and is expressed only in a few cells, but it is able to sustain double null mutants ace-1; ace-2. It is resistant to usual cholinesterase inhibitors. ace-4 was transcribed but the corresponding enzyme was not detected in vivo.

  17. 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.

  18. A white paper on nematode comparative genomics.

    Science.gov (United States)

    Bird, David McK; Blaxter, Mark L; McCarter, James P; Mitreva, Makedonka; Sternberg, Paul W; Thomas, W Kelley

    2005-12-01

    In response to the new opportunities for genome sequencing and comparative genomics, the Society of Nematology (SON) formed a committee to develop a white paper in support of the broad scientific needs associated with this phylum and interests of SON members. Although genome sequencing is expensive, the data generated are unique in biological systems in that genomes have the potential to be complete (every base of the genome can be accounted for), accurate (the data are digital and not subject to stochastic variation), and permanent (once obtained, the genome of a species does not need to be experimentally re-sampled). The availability of complete, accurate, and permanent genome sequences from diverse nematode species will underpin future studies into the biology and evolution of this phylum and the ecological associations (particularly parasitic) nematodes have with other organisms. We anticipate that upwards of 100 nematode genomes will be solved to varying levels of completion in the coming decade and suggest biological and practical considerations to guide the selection of the most informative taxa for sequencing.

  19. Nematode locomotion in unconfined and confined fluids

    Science.gov (United States)

    Bilbao, Alejandro; Wajnryb, Eligiusz; Vanapalli, Siva A.; Blawzdziewicz, Jerzy

    2013-08-01

    The millimeter-long soil-dwelling nematode Caenorhabditis elegans propels itself by producing undulations that propagate along its body and turns by assuming highly curved shapes. According to our recent study [V. Padmanabhan et al., PLoS ONE 7, e40121 (2012), 10.1371/journal.pone.0040121] all these postures can be accurately described by a piecewise-harmonic-curvature model. We combine this curvature-based description with highly accurate hydrodynamic bead models to evaluate the normalized velocity and turning angles for a worm swimming in an unconfined fluid and in a parallel-wall cell. We find that the worm moves twice as fast and navigates more effectively under a strong confinement, due to the large transverse-to-longitudinal resistance-coefficient ratio resulting from the wall-mediated far-field hydrodynamic coupling between body segments. We also note that the optimal swimming gait is similar to the gait observed for nematodes swimming in high-viscosity fluids. Our bead models allow us to determine the effects of confinement and finite thickness of the body of the nematode on its locomotion. These effects are not accounted for by the classical resistive-force and slender-body theories.

  20. Development of a pathway model to assess the exposure of European pine trees to pine wood nematode via the trade of wood.

    Science.gov (United States)

    Douma, J C; van der Werf, W; Hemerik, L; Magnusson, C; Robinet, C

    2017-04-01

    Pine wood nematode (PWN), Bursaphelenchus xylophilus, is a threat for pine species (Pinus spp.) throughout the world. The nematode is native to North America, and invaded Japan, China, Korea, and Taiwan, and more recently Portugal and Spain. PWN enters new areas through trade in wood products. Once established, eradication is not practically feasible. Therefore, preventing entry of PWN into new areas is crucial. Entry risk analysis can assist in targeting management to reduce the probability of entry. Assessing the entry of PWN is challenging due to the complexity of the wood trade and the wood processing chain. In this paper, we develop a pathway model that describes the wood trade and wood processing chain to determine the structure of the entry process. We consider entry of PWN through imported coniferous wood from China, a possible origin of Portuguese populations, to Europe. We show that exposure increased over years due to an increase in imports of sawn wood. From 2000 to 2012, Europe received an estimated 84 PWN propagules from China, 88% of which arose from imported sawn wood and 12% from round wood. The region in Portugal where the PWN was first reported is among those with the highest PWN transfer per unit of imported wood due to a high host cover and vector activity. An estimated 62% of PWN is expected to enter in countries where PWN is not expected to cause the wilt of pine trees because of low summer temperatures (e.g., Belgium, Sweden, Norway). In these countries, PWN is not easily detected, and such countries can thus serve as potential reservoirs of PWN. The model identifies ports and regions with high exposure, which helps targeting monitoring and surveillance, even in areas where wilt disease is not expected to occur. In addition, we show that exposure is most efficiently reduced by additional treatments in the country of origin, and/or import wood from PWN-free zones. Pathway modelling assists plant health managers in analyzing risks along the

  1. Extracting DNA of nematodes communities from Argentine Pampas agricultural soils

    Directory of Open Access Journals (Sweden)

    Eduardo A. Mondino

    2015-06-01

    Full Text Available We examined four strategies (Tris/EDTA, sodium dodecyl sulfate, Chelex 100 resin and cetyltrimethylammonium bromide -CTAB- for extracting nucleic acid (DNA from communities of nematodes. Nematodes were isolated from an agricultural area under different management of long-term crop rotation experiment from Argentina during three seasons. After DNA extraction, Polymerase Chain Reaction-amplifications were performed and considered as indicators of successful DNA extraction. The CTAB combined with proteinase K and phenol-chloroform-isoamyl alcohol was the unique successful method because positive amplifications were obtained by using both eukaryotic and nematode specific primers. This work could contribute to biodiversity studies of nematodes on agroecosystems.

  2. Extracting DNA of nematodes communities from Argentine Pampas agricultural soils.

    Science.gov (United States)

    Mondino, Eduardo A; Covacevich, Fernanda; Studdert, Guillermo A; Pimentel, João P; Berbara, Ricardo L L

    2015-01-01

    We examined four strategies (Tris/EDTA, sodium dodecyl sulfate, Chelex 100 resin and cetyltrimethylammonium bromide -CTAB-) for extracting nucleic acid (DNA) from communities of nematodes. Nematodes were isolated from an agricultural area under different management of long-term crop rotation experiment from Argentina during three seasons. After DNA extraction, Polymerase Chain Reaction-amplifications were performed and considered as indicators of successful DNA extraction. The CTAB combined with proteinase K and phenol-chloroform-isoamyl alcohol was the unique successful method because positive amplifications were obtained by using both eukaryotic and nematode specific primers. This work could contribute to biodiversity studies of nematodes on agroecosystems.

  3. 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.

  4. Hybridization between Bursaphelenchus xylophilus and B. mucronatus and Reproduction of the Offspring%松材线虫与拟松材线虫杂交及后代繁殖力1)

    Institute of Scientific and Technical Information of China (English)

    刘侃诚; 曹东霞; 田兴一; 李警保; 韩正敏

    2015-01-01

    In our study different isolates of Bursaphelenchus xylophilus and B. mucronatus were collected from different origins. Interspecific hybridization, successive transfer culture and backcross test were conducted in the laboratory. The combina⁃tions of B. xylophilus from Zhejiang hybridizes and B. mucronatus from France or B. mucronatus from China had high hybrid rate, large number of descendants, and low death rate. In subculture tests, both combinations had a strong reproductive advantage. The hybrid offspring of two combinations could cross with parents, especially the B. mucronatus. Therefore, there is interspecific hybridization between some B. xylophilus and B. mucronatus actually. The hybrids can establish stable population, and there is the hybrid offspring of B. xylophilus and B. mucronatus exist in natural conditions.%为了探明松材线虫( Bursaphelenchus xylophilus)与拟松材线虫( Bursaphelenchus mucronatus)能否进行种间杂交,收集了不同地理来源的松材线虫和拟松材线虫株系,在实验室内进行了种间杂交、继代培养以及回交。结果显示:中国浙江松材线虫和法国拟松材线虫、中国浙江松材线虫和中国拟松材线虫杂交组合,具有较高的交配率、繁殖量和低死亡率。在继代培养试验中,这2个组合都具有很强的繁殖优势,其杂交后代可以同亲本回交,且更趋于同拟松材线虫回交。总的来说,松材线虫和拟松材线虫有些虫株间是可以杂交并能够顺利繁殖,建立可延续的种群的。推测在自然条件下,松材线虫和拟松材线虫杂交后代是存在的。

  5. 松材线虫雌虫尾部形态和寄主的关系%The Relationship between the Tail Morphology of Adult Female Bursaphelenchus xylophilus and Its Host

    Institute of Scientific and Technical Information of China (English)

    赵文霞; 杨宝君

    2005-01-01

    Tenninal mucro of adult female was the distinct character between Bursaphelenchus xylophilus (Bx) and its allied species Bursaphe/enchus mucronatus (Bb). In general, Bx had no mucro. But it could have mucro in some situations. In the test, Bx without mucro was inoculated on Chineses pine (Pinus tabulaeformis) and Japanese black pine (Pinus thunbergii). The results showed that 85% of adult females Bx isolated from Chinese pine had terminal mucro. On Japanese black pine only 4.2% of adult females Bx had terminal mucro. Bx with terminal mucro from Chinese pine was re-inoculated on the fungus, Pestalotia sp. and Japanese black pine. It was found that 100% adult females had no terminal mucro on the fungus and 3.4% with terminal mucro on Japanese black pine.

  6. 苍山斜阳峰火烧迹地捕食线虫真菌资源调查%Investigation on Nematode-trapping Fungi in Burned Areas of Xieyang Peak in Cangshan Mountain

    Institute of Scientific and Technical Information of China (English)

    李云霞; 杨晓燕; 苏鸿雁

    2012-01-01

    [Objective] The aim was to study the nematode-trapping fungi in burned areas of Xieyang Peak in Cangshan Mountain. [Method] Total 480 soil samples were collected from rhizosphere soil of armand pine and Yunnan pine of 6 burned areas of Xieyang Peak in Cangshan Mountain. Nematode-trapping fungi in soil samples were isolated by the method of baited plates and identified. [ Result] Total 79 strains were i-solated, and they were 6 species belonged to 2 genera. The nematode-trapping fungi were the most widely distributed in burned area of Atoyama of General's cave, and 80 soil samples were totally detected for 17 times. Among 6 burned areas, A. oligospora had the highest detection rate, with 4.79% ; next came A. musifomis and M. ellipasosperum, with detection rales of 3.96% and 3.75% , respectively. [ Conclusion ] The research accumulates strain resources for the biological control of Bursaphelenchus xylophilus.%[目的]研究苍山斜阳峰火烧迹地捕食线虫真菌.[方法]从云南大理苍山地区斜阳峰6块火烧迹地的华山松、云南松松树根际土共采集了480份土样,采用诱饵平板法对土样中捕食线虫真菌资源进行分离并对其进行了鉴定.[结果]共分离出79株菌株,经鉴定有2个属6个种.捕食线虫真菌在将军洞后山火烧迹地分布最广,80份土样共计检出17次.6块火烧迹地中,少孢节丛孢(A.oligospora)的检出率最高,为4.79%;其次是弯孢节丛孢(A.musifomis)和椭圆单顶孢(M.ellipososporum),检出率分别为3.96%和3.75%.[结论]为松材线虫的生物防治积累了菌种资源.

  7. 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

  8. 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...

  9. Plant ectoparasitic nematodes prefer roots without their microbial enemies

    NARCIS (Netherlands)

    Piskiewicz, A.M.; Milliano, de M.J.K.; Duyts, H.; Putten, van der W.H.

    2009-01-01

    Root-feeding nematodes are major soil-borne pests in agriculture. In natural ecosystems, their abundance can be strongly controlled by natural enemies. In coastal foredune soil, the abundance of the ectoparasitic nematode Tylenchorhynchus ventralis is controlled by local interactions with soil

  10. Transgenesis in parasitic nematodes: building a better array

    OpenAIRE

    Lok, James B.

    2009-01-01

    In spite of recent progress in the development of transgenesis in parasitic nematodes, several impediments remain before this methodology can become a practical and widely employed tool in parasitology. Recently published studies on transgenesis in the necromenic nematode Pristionchus pacificus from the laboratory of Ralf Sommer highlight several leads that might be valuable as efforts to refine current systems in obligate parasites go forward.

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

    African Journals Online (AJOL)

    (p<0.05) the nematode egg hatching as well as juvenile motility over the untreated control. Higher ... the pot house experiment. .... and placed to a drop of glycerine on a clean glass slide with ... knot nematode for subsequent experiments in the.

  12. Sex-specific mating pheromones in the nematode Panagrellus redivivus

    Science.gov (United States)

    Despite advances in medicine and crop genetics, nematodes remain significant human pathogens and agricultural pests. This warrants investigation of alternative strategies for pest control, such as interference with pheromone-mediated reproduction. Because only two nematode species have had their phe...

  13. Soybean lines evaluated for resistance to reniform nematode

    Science.gov (United States)

    Seventy-four wild and domestic soybean (Glycine max and G. soja) lines were evaluated for resistance to reniform nematode (Rotylenchulus reniformis) in growth chamber tests with a day length of 16 hours and temperature held constant at 28 C. Several entries for which reactions to reniform nematode w...

  14. A satellite explosion in the genome of holocentric nematodes.

    Directory of Open Access Journals (Sweden)

    Juan A Subirana

    Full Text Available Centromere sequences in the genome are associated with the formation of kinetochores, where spindle microtubules grow in mitosis. Centromere sequences usually have long tandem repeats (satellites. In holocentric nematodes it is not clear how kinetochores are formed during mitosis; they are distributed throughout the chromosomes. For this reason it appeared of interest to study the satellites in nematodes in order to determine if they offer any clue on how kinetochores are assembled in these species. We have studied the satellites in the genome of six nematode species. We found that the presence of satellites depends on whether the nematode chromosomes are holocentric or monocentric. It turns out that holocentric nematodes are unique because they have a large number of satellites scattered throughout their genome. Their number, length and composition are different in each species: they apparently have very little evolutionary conservation. In contrast, no scattered satellites are found in the monocentric nematode Trichinella spiralis. It appears that the absence/presence of scattered satellites in the genome distinguishes monocentric from holocentric nematodes. We conclude that the presence of satellites is related to the holocentric nature of the chromosomes of most nematodes. Satellites may stabilize a higher order structure of chromatin and facilitate the formation of kinetochores. We also present a new program, SATFIND, which is suited to find satellite sequences.

  15. Systematics, ecology and feeding biology of estuarine nematodes

    NARCIS (Netherlands)

    Bouwman, L.A.

    1983-01-01

    As part of extensive biological and chemical investigations in the Ems estuary, the nematode fauna of this area (mainly located in the sediments of tidal flats) was studied.First, a new method of isolating nematodes was developed, as none of the existing methods appeared to be quantitatively reliabl

  16. 76 FR 60357 - Golden Nematode; Removal of Regulated Areas

    Science.gov (United States)

    2011-09-29

    ... Animal and Plant Health Inspection Service 7 CFR Part 301 Golden Nematode; Removal of Regulated Areas... Genesee County, NY, from the list of generally infested areas. Surveys have shown that the fields in these two townships are free of golden nematode, and we have determined that regulation of these areas is...

  17. [Resistance to anthelmintics in nematodes in sheep and goats].

    Science.gov (United States)

    Praslicka, J; Corba, J

    1995-08-01

    The article offers a brief view on the most important theoretical knowledge of resistance of gastrointestinal nematodes to anthelmintic drugs in sheep and goats. Besides the definition and basic terms, factors of development and occurrence of resistance on farm are analyzed. Furthermore, methods for detection of resistant nematodes as well as complex of recommended preventive measures are given.

  18. Control of the peachtree borer using beneficial nematodes

    Science.gov (United States)

    The peachtree borer, Synanthedon exitiosa, is a major pest of peaches and other stone fruits. Our research indicates that entomopathogenic nematodes, also known as beneficial nematodes, can be used effectively to control the insect. We conducted replicated experiments in randomized block designs ov...

  19. Pineapple nematode research in hawaii: past, present, and future.

    Science.gov (United States)

    Caswell, E P; Apt, W J

    1989-04-01

    The first written record of pineapple in Hawaii is from 1813. In 1901 commercial pineapple production started, and in 1924 the Experiment Station for pineapple research was established. Nematode-related problems were recognized in the early 1900s by N. A. Cobb. From 1920 to approximately 1945 nematode management in Hawaiian pineapple was based on fallowing and crop rotation. During the 1920s and 1930s G. H. Godfrey conducted research on pineapple nematode management. In the 1930s and 1940s M. B. Linford researched biological control and described several new species of nematodes including Rotylenchulus reniformis. In 1941 nematology and nematode management were advanced by Walter Carter's discovery of the first economical soil fumigant for nematodes, D-D mixture. Subsequently, DBCP was discovered and developed at the Pineapple Research Institute (PRI). Since 1945 soil fumigation has been the main nematode management strategy in Hawaiian pineapple production. Recent research has focused on the development of the nonvolatile nematicides, their potential as systemic nematicides, and their application via drip irrigation. Current and future research addresses biological and cultural alternatives to nematicide-based nematode management.

  20. 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.

  1. Transgenic Strategies for Enhancement of Nematode Resistance in Plants.

    Science.gov (United States)

    Ali, Muhammad A; Azeem, Farrukh; Abbas, Amjad; Joyia, Faiz A; Li, Hongjie; Dababat, Abdelfattah A

    2017-01-01

    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.

  2. Conserved nematode signaling molecules elicit plant defenses and pathogen resistance

    Science.gov (United States)

    Nematodes, which are ubiquitous in soil and are estimated to cause $100 B of agricultural damage annually, produce novel, highly conserved small sugar-based molecules call ascarosides. Ascarosides play critical roles in nematode development and behavior. We report here that plants recognize these un...

  3. 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 rostochiensis comp

  4. Plant ectoparasitic nematodes prefer roots without their microbial enemies

    NARCIS (Netherlands)

    Piskiewicz, A.M.; Milliano, de M.J.K.; Duyts, H.; Putten, van der W.H.

    2009-01-01

    Root-feeding nematodes are major soil-borne pests in agriculture. In natural ecosystems, their abundance can be strongly controlled by natural enemies. In coastal foredune soil, the abundance of the ectoparasitic nematode Tylenchorhynchus ventralis is controlled by local interactions with soil micro

  5. Creolina effect on the parasitic nematodes on tobacco crop

    Directory of Open Access Journals (Sweden)

    Ricardo Bemfica Steffen

    2010-06-01

    Full Text Available Tobacco is a culture with great economic importance in the Rio Grande do Sul State, It is usually cultivated in small areas using family work force. The nematodes are organisms that cause damages to the tobacco and limit the development and production. The aim of this work was to evaluate the use of the creolina as measure alternative of nematofauna control. In controlled conditions, the creolina applications solutions at 10 and 20% presented efficiency of 74 and 85% in the nematodes inactivation, respectively. In field conditions, the application of the creolina solution at 10% in revolved soil provided decrease of 50% in the total number of nematodes in the soil and it presented efficiency of 45% in the present nematodes inactivation, showed a great potential in the integrated handling of nematodes in small cultivated areas with tabacum.

  6. 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.

  7. Co-adaptation mechanisms in plant-nematode systems.

    Science.gov (United States)

    Zinovieva, S V

    2014-01-01

    The review is aimed to analyze the biochemical and immune-breaking adaptive mechanisms established in evolution of plant parasitic nematodes. Plant parasitic nematodes are obligate, biotrophic pathogens of numerous plant species. These organisms cause dramatic changes in the morphology and physiology of their hosts. The group of sedentary nematodes which are among the most damaging plant-parasitic nematodes cause the formation of special organs called nematode feeding sites in the root tissue called syncytium (cyst nematodes, CN; Heterodera and Globodera spp.) or giant cells (root-knot nematodes, RKN; Meloidogyne spp.). The most pronounced morphological adaptations of nematodes for plant parasitism include a hollow, protrusible stylet (feeding spear) connected to three esophageal gland cells that express products secreted into plant tissues through the stylet. Several gene products secreted by the nematode during parasitism have been identified. The current battery of candidate parasitism proteins secreted by nematodes to modify plant tissues for parasitism includes cell-wall-modifying enzymes, multiple regulators of host cell cycle and metabolism, proteins that can localize near the plant cell nucleus, potential suppressors of host defense, and mimics of plant molecules. Plants are usually able to recognize and react to parasites by activating various defense responses. When the response of the plant is too weak or too late, a successful infection (compatible interaction) will result. A rapid and strong defense response (e. g. due to the presence of a resistance gene) will result in the resistant (incompatible) reaction. Defense responses include the production of toxic oxygen radicals and systemic signaling compounds as well as the activation of defense genes that lead to the production of structural barriers or other toxins.

  8. Soil microorganisms control plant ectoparasitic nematodes in natural coastal foredunes.

    Science.gov (United States)

    Piśkiewicz, Anna M; Duyts, Henk; Berg, Matty P; Costa, Sofia R; van der Putten, Wim H

    2007-06-01

    Belowground herbivores can exert important controls on the composition of natural plant communities. Until now, relatively few studies have investigated which factors may control the abundance of belowground herbivores. In Dutch coastal foredunes, the root-feeding nematode Tylenchorhynchus ventralis is capable of reducing the performance of the dominant grass Ammophila arenaria (Marram grass). However, field surveys show that populations of this nematode usually are controlled to nondamaging densities, but the control mechanism is unknown. In the present study, we first established that T. ventralis populations are top-down controlled by soil biota. Then, selective removal of soil fauna suggested that soil microorganisms play an important role in controlling T. ventralis. This result was confirmed by an experiment where selective inoculation of microarthropods, nematodes and microbes together with T. ventralis into sterilized dune soil resulted in nematode control when microbes were present. Adding nematodes had some effect, whereas microarthropods did not have a significant effect on T. ventralis. Our results have important implications for the appreciation of herbivore controls in natural soils. Soil food web models assume that herbivorous nematodes are controlled by predaceous invertebrates, whereas many biological control studies focus on managing nematode abundance by soil microorganisms. We propose that soil microorganisms play a more important role than do carnivorous soil invertebrates in the top-down control of herbivorous ectoparasitic nematodes in natural ecosystems. This is opposite to many studies on factors controlling root-feeding insects, which are supposed to be controlled by carnivorous invertebrates, parasitoids, or entomopathogenic nematodes. Our conclusion is that the ectoparasitic nematode T. ventralis is potentially able to limit productivity of the dune grass A. arenaria but that soil organisms, mostly microorganisms, usually prevent the

  9. Assessment of nematode biodiversity using DGGE of 18S rDNA following extraction of nematodes from soil

    NARCIS (Netherlands)

    Foucher, A.L.J.L.; Bongers, A.M.T.; Noble, L.R.; Wilson, M.J.

    2004-01-01

    Soil nematodes are both taxonomically and functionally diverse, respond quickly to soil perturbation and have much potential as indicators of soil health. However, because of the perceived difficulty of identifying nematodes to species level morphologically, they are frequently neglected in soil eco

  10. 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.

  11. 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.

  12. 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.

  13. Nematode Locomotion in Unconfined and Confined Fluids

    CERN Document Server

    Bilbao, Alejandro; Vanapalli, Siva; Blawzdziewicz, Jerzy

    2013-01-01

    The millimeter-long soil-dwelling nematode {\\it C. elegans} propels itself by producing undulations that propagate along its body and turns by assuming highly curved shapes. According to our recent study [PLoS ONE \\textbf{7}, e40121 (2012)] all these postures can be accurately described by a piecewise-harmonic-curvature (PHC) model. We combine this curvature-based description with highly accurate hydrodynamic bead models to evaluate the normalized velocity and turning angles for a worm swimming in an unconfined fluid and in a parallel-wall cell. We find that the worm moves twice as fast and navigates more effectively under a strong confinement, due to the large transverse-to-longitudinal resistance-coefficient ratio resulting from the wall-mediated far-field hydrodynamic coupling between body segments. We also note that the optimal swimming gait is similar to the gait observed for nematodes swimming in high-viscosity fluids. Our bead models allow us to determine the effects of confinement and finite thickness...

  14. 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.

  15. Pack hunting by a common soil amoeba on nematodes.

    Science.gov (United States)

    Geisen, Stefan; Rosengarten, Jamila; Koller, Robert; Mulder, Christian; Urich, Tim; Bonkowski, Michael

    2015-11-01

    Soils host the most complex communities on Earth, including the most diverse and abundant eukaryotes, i.e. heterotrophic protists. Protists are generally considered as bacterivores, but evidence for negative interactions with nematodes both from laboratory and field studies exist. However, direct impacts of protists on nematodes remain unknown. We isolated the soil-borne testate amoeba Cryptodifflugia operculata and found a highly specialized and effective pack-hunting strategy to prey on bacterivorous nematodes. Enhanced reproduction in presence of prey nematodes suggests a beneficial predatory life history of these omnivorous soil amoebae. Cryptodifflugia operculata appears to selectively impact the nematode community composition as reductions of nematode numbers were species specific. Furthermore, we investigated 12 soil metatranscriptomes from five distinct locations throughout Europe for 18S ribosomal RNA transcripts of C. operculata. The presence of C. operculata transcripts in all samples, representing up to 4% of the active protist community, indicates a potential ecological importance of nematophagy performed by C. operculata in soil food webs. The unique pack-hunting strategy on nematodes that was previously unknown from protists, together with molecular evidence that these pack hunters are likely to be abundant and widespread in soils, imply a considerable importance of the hitherto neglected trophic link 'nematophagous protists' in soil food webs.

  16. 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

  17. Suppression of plant parasitic nematodes in the chinampa agricultural soils.

    Science.gov (United States)

    Zuckerman, B M; Dicklow, M B; Coles, G C; Garcia-E, R; Marban-Mendoza, N

    1989-06-01

    Soil from the chinampa agricultural system in the Valley of Mexico suppressed damage by plant-parasitic nematodes to tomatoes and beans in greenhouse and growth chamber trials. Sterilization of the chinampa soil resulted in a loss of the suppressive effect, thereby indicating that one or more biotic factors were responsible for the low incidence of nematode damage. Nine organisms were isolated from chinampa soil, which showed antinematodal properties in culture. Naturally occurring populations of plant-parasitic nematodes were of lower incidence in chinampa soil than in Chapingo soil.

  18. 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.

  19. Detection and quantification of root-knot nematode (Meloidogyne javanica), lesion nematode (Pratylenchus zeae) and dagger nematode (Xiphinema elongatum) parasites of sugarcane using real-time PCR.

    Science.gov (United States)

    Berry, Shaun D; Fargette, Mireille; Spaull, Vaughan W; Morand, Serge; Cadet, Patrice

    2008-06-01

    A number of different plant parasitic nematode species are found associated with sugarcane in South Africa. Of these, the root-knot nematode (Meloidogyne javanica), the lesion nematode (Pratylenchus zeae) and the dagger nematode (Xiphinema elongatum) are potentially the most damaging pests. Identification and enumeration of the number of these nematodes are necessary for providing advice to farmers as well as studying the effects of various treatments in field and glasshouse trials. We report on the development, use, and extent of specificity of three sets of primers, for M. javanica, P. zeae and X. elongatum, and on tests to detect and quantify the number of these nematodes in soil samples using SYBR Green I dye and real-time PCR technology. Amplicons from the three target species (obtained with their respective primer sets) are discernible in size by gel electrophoresis (380bp for M. javanica, 250bp for P. zeae and 500bp for X. elongatum). Also, these amplicons have characteristic melting temperatures of 83.8 degrees C (M. javanica), 86.6 degrees C (P. zeae) and 86.1 degrees C (X. elongatum). Investigations into multiplex reactions found competition between species with M. javanica competing with P. zeae and X. elongatum. Subsequent single tube (simplex) assays, enabled the construction of calibration curves for each of the three species. These were then used for quantification of the numbers of each of these species in nematode samples extracted from the field, with a high (R2=0.83) and significant positive correlation between real-time PCR and counts performed with microscopy.

  20. Nematode parasite genes: what's in a name?

    Science.gov (United States)

    Beech, Robin N; Wolstenholme, Adrian J; Neveu, Cédric; Dent, Joseph A

    2010-07-01

    The central theme of Shakespeare's Romeo and Juliet is that names are meaningless, artificial constructs, detached from any underlying reality. By contrast, we argue that a well chosen gene name can concisely convey a wealth of relevant biological information. A consistent nomenclature adds transparency that can have a real impact on our understanding of gene function. Currently, genes in parasitic nematodes are often named ad hoc, leading to confusion that can be resolved by adherence to a nomenclature standard adapted from Caenorhabditis elegans. We demonstrate this with ligand-gated ion-channels and propose that the flood of genome data and differences between parasites and the free living C. elegans will require modification of the standard.

  1. Are nematode collections in danger of extinction?

    Science.gov (United States)

    Hockland, S; Hoestra, H

    2003-01-01

    The correct identification of pest organisms, including plant-parasitic nematodes, is the essential foundation for integrated pest programmes and government policy decisions involving trade. A plethora of identification methods have been developed but the basis for identification remains essentially morphological in nature, with invertebrate collections forming the ultimate reference facility. However, a continuing decline in funds for the preservation and curation of collections and for the development of taxonomists is leading to a deterioration in the quality of standards. The development of computer technology associated with digital images and their analysis provides the possibility of not only attracting resources but also of exposing collections to international use in ways not previously possible. The time is right to develop a European strategy to save and develop collections and taxonomy.

  2. (Musa AAA) root nematode control and crop yield

    African Journals Online (AJOL)

    SARAH

    2016-05-31

    May 31, 2016 ... Key words: Chemical control, Musa AAA, nematode control, nematicides. INTRODUCTION ... Thorne 1949, Sher 1968) and Helicotylenchus spp. To avoid or ... Belize with a plant density of 2000 plants ha-1. Desuckering was ...

  3. Soil microorganisms control plant ectoparasitic nematodes in natural coastal foredunes

    NARCIS (Netherlands)

    Piskiewicz, A.M.; Duyts, H.; Berg, M.P.; Costa, S.R.; Putten, van der W.H.

    2007-01-01

    Belowground herbivores can exert important controls on the composition of natural plant communities. Until now, relatively few studies have investigated which factors may control the abundance of belowground herbivores. In Dutch coastal foredunes, the root-feeding nematode Tylenchorhynchus ventralis

  4. Conserved nematode signalling molecules elicit plant defenses and pathogen resistance

    National Research Council Canada - National Science Library

    Manosalva, Patricia; Manohar, Murli; von Reuss, Stephan H; Chen, Shiyan; Koch, Aline; Kaplan, Fatma; Choe, Andrea; Micikas, Robert J; Wang, Xiaohong; Kogel, Karl-Heinz; Sternberg, Paul W; Williamson, Valerie M; Schroeder, Frank C; Klessig, Daniel F

    2015-01-01

    .... Picomolar to micromolar concentrations of ascr#18, the major ascaroside in plant-parasitic nematodes, induce hallmark defense responses including the expression of genes associated with MAMP-triggered immunity, activation of mitogen-activated...

  5. Nematode Faunal Response to Grassland Degradation in Horqin Sandy Land

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The responses of soil nematode communities to grassland degradation were studied under undegraded grassland (UG),degraded grassland (DG), and improved grassland (IG), in Horqin Sandy Land, Inner Mongolia, Northeast China. Soil samples were collected at depths of 0-10, 10-20, and 20-30 cm. Total organic carbon (TOC) and total nitrogen (TN)exhibited positive effects on the total number of nematodes and trophic groups. Significant treatment effects were found in the total number of nematodes, plant parasites, and omnivores-predators. Measures taken in the improved grassland could improve the number of omnivore-predators, especially in the deeper soil layers. Nematode richness was lower in the DG treatment than in the IG and UG treatments. The food web structure index (SI) was significantly higher in the UG and IG treatments than in the DG treatment. A higher SI suggested a food web with more trophic linkages and relatively healthy ecosystems.

  6. 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.

  7. Soil microorganisms control plant ectoparasitic nematodes in natural coastal foredunes

    NARCIS (Netherlands)

    Piskiewicz, A.M.; Duyts, H.; Berg, M.P.; Costa, S.R.; Putten, van der W.H.

    2007-01-01

    Belowground herbivores can exert important controls on the composition of natural plant communities. Until now, relatively few studies have investigated which factors may control the abundance of belowground herbivores. In Dutch coastal foredunes, the root-feeding nematode Tylenchorhynchus ventralis

  8. Survey of fresh vegetables for nematodes, amoebae, and Salmonella.

    Science.gov (United States)

    Rude, R A; Jackson, G J; Bier, J W; Sawyer, T K; Risty, N G

    1984-01-01

    Contamination by nematodes, amoebae, and bacteria of the genus Salmonella was estimated in a 2-year survey of salad vegetables obtained from wholesale and retail sources. The vegetables examined were cucumbers, cabbage, lettuce, celery, carrots, radishes, tomatoes, mushrooms, cauliflower, and spinach. Nematode eggs and larvae were recovered by the Nacconol-ether centrifugation method. Some nematode eggs were identified as parasitic Ascaris sp.; the majority of larval nematodes were thought to be soil-dwelling species. Amoebae were recovered by rinsing the vegetables with distilled water, centrifuging the rinse water, and transferring the sediment to agar plates on which a bacterial lawn had previously been grown; trophozoites identified as the potentially pathogenic species--Acanthamoeba polyphaga, A. rhysodes, and A. castellanii--were the most common amoebae recovered on the plates. Salmonella spp. were grown from 4 of 50 samples.

  9. [Effects of phytase transgenic corn planting on soil nematode community].

    Science.gov (United States)

    Zhao, Zong-Chao; Su, Ying; Mou, Wen-Ya; Liu, Man-Qiang; Chen, Xiao-Yun; Chen, Fa-Jun

    2014-04-01

    A healthy soil ecosystem is essential for nutrient cycling and energy conversion, and the impact of exogenous genes from genetically modified crops had aroused wide concerns. Phytase transgenic corn (i. e., the inbred line BVLA430101) was issued a bio-safety certificate on 27 September 2009 in China, which could improve the efficiency of feed utilization, reduce environmental pollution caused by animal manure. In this study, the abundance of trophic groups, community structure and ecological indices of soil nematodes were studied over the growing cycle of phytase transgenic corn (ab. transgenic corn) and control conventional parental corn (ab. control corn) in the field. Totally 29 and 26 nematode genera were isolated from transgenic corn and control corn fields, respectively. The abundances of bacterivores and omnivores-predators, the total number of soil nematodes, and the Shannon index (H) were significantly greater under transgenic corn than under control corn, while the opposite trend was found for the relative abundance of herbivores and the maturity index (Sigma MI) of soil nematodes. Repeated-measures analysis of variance (ANOVA) did not detect any significant effects of transgenic corn on the composition and abundance of nematode trophic groups and ecological indices of soil nematodes. Furthermore, the Student-T test showed that the abundances of bacterivores and omnivores-predators and the total number of soil nematodes during the milk-ripe stage were significant higher in the transgenic corn field than in the control corn field. The effects of transgenic corn planting on soil nematodes might be related to the increase in the nitrogen content of field soil under transgenic corn compared to control corn.

  10. Entomopathogenic Nematodes for the Biological Control of Pest Insects

    OpenAIRE

    Ljerka Oštrec

    2001-01-01

    Entomopathogenic nematodes are part of 9 families, but only some species of these families: Heterorhabditidae, Mermithidae and Steinernematidae kill insects. Infective juveniles enter the insect host through the cuticle, or through the mouth, anus, etc., to reach the haemocel. The infective juveniles also enter the insect by the foot. After that the nematodes leave the insect who usually dies. The infective juveniles are associated with symbiotic bacterium (Xenorhabdus, Photorhabdus) which h...

  11. Sex-specific mating pheromones in the nematode Panagrellus redivivus

    OpenAIRE

    Choe, Andrea; Chuman, Tatsuji; von Reuss, Stephan H.; Dossey, Aaron T.; Yim, Joshua J.; Ajredini, Ramadan; Kolawa, Adam A.; Kaplan, Fatma; Alborn, Hans T.; Teal, Peter E. A.; Schroeder, Frank C.; Paul W. Sternberg; EDISON, ARTHUR S.

    2012-01-01

    Nematodes use an extensive chemical language based on glycosides of the dideoxysugar ascarylose for developmental regulation (dauer formation), male sex attraction, aggregation, and dispersal. However, no examples of a female- or hermaphrodite-specific sex attractant have been identified to date. In this study, we investigated the pheromone system of the gonochoristic sour paste nematode Panagrellus redivivus, which produces sex-specific attractants of the opposite sex. Activity-guided fracti...

  12. Entomopathogenic Nematodes for the Biological Control of Pest Insects

    OpenAIRE

    Ljerka Oštrec

    2001-01-01

    Entomopathogenic nematodes are part of 9 families, but only some species of these families: Heterorhabditidae, Mermithidae and Steinernematidae kill insects. Infective juveniles enter the insect host through the cuticle, or through the mouth, anus, etc., to reach the haemocel. The infective juveniles also enter the insect by the foot. After that the nematodes leave the insect who usually dies. The infective juveniles are associated with symbiotic bacterium (Xenorhabdus, Photorhabdus) which h...

  13. Diverse host-seeking behaviors of skin-penetrating nematodes.

    Directory of Open Access Journals (Sweden)

    Michelle L Castelletto

    2014-08-01

    Full Text Available Skin-penetrating parasitic nematodes infect approximately one billion people worldwide and are responsible for some of the most common neglected tropical diseases. The infective larvae of skin-penetrating nematodes are thought to search for hosts using sensory cues, yet their host-seeking behavior is poorly understood. We conducted an in-depth analysis of host seeking in the skin-penetrating human parasite Strongyloides stercoralis, and compared its behavior to that of other parasitic nematodes. We found that Str. stercoralis is highly mobile relative to other parasitic nematodes and uses a cruising strategy for finding hosts. Str. stercoralis shows robust attraction to a diverse array of human skin and sweat odorants, most of which are known mosquito attractants. Olfactory preferences of Str. stercoralis vary across life stages, suggesting a mechanism by which host seeking is limited to infective larvae. A comparison of odor-driven behavior in Str. stercoralis and six other nematode species revealed that parasite olfactory preferences reflect host specificity rather than phylogeny, suggesting an important role for olfaction in host selection. Our results may enable the development of new strategies for combating harmful nematode infections.

  14. Temperature-based bioclimatic parameters can predict nematode metabolic footprints.

    Science.gov (United States)

    Bhusal, Daya Ram; Tsiafouli, Maria A; Sgardelis, Stefanos P

    2015-09-01

    Nematode metabolic footprints (MFs) refer to the lifetime amount of metabolized carbon per individual, indicating a connection to soil food web functions and eventually to processes supporting ecosystem services. Estimating and managing these at a convenient scale requires information upscaling from the soil sample to the landscape level. We explore the feasibility of predicting nematode MFs from temperature-based bioclimatic parameters across a landscape. We assume that temperature effects are reflected in MFs, since temperature variations determine life processes ranging from enzyme activities to community structure. We use microclimate data recorded for 1 year from sites differing by orientation, altitude and vegetation cover. At the same sites we estimate MFs for each nematode trophic group. Our models show that bioclimatic parameters, specifically those accounting for temporal variations in temperature and extremities, predict most of the variation in nematode MFs. Higher fungivorous and lower bacterivorous nematode MFs are predicted for sites with high seasonality and low isothermality (sites of low vegetation, mostly at low altitudes), indicating differences in the relative contribution of the corresponding food web channels to the metabolism of carbon across the landscape. Higher plant-parasitic MFs were predicted for sites with high seasonality. The fitted models provide realistic predictions of unknown cases within the range of the predictor's values, allowing for the interpolation of MFs within the sampled region. We conclude that upscaling of the bioindication potential of nematode communities is feasible and can provide new perspectives not only in the field of soil ecology but other research areas as well.

  15. A Device to Measure the Propulsive Power of Nematodes

    CERN Document Server

    Yuan, J; Gnatt, M; Raizen, D M; Bau, H H

    2011-01-01

    In the fluid dynamics video, we present a microfluidic device to measure the propulsive power of nematodes. The device consists of a tapered conduit filled with aqueous solution. The conduit is subjected to a DC electric field with the negative pole at the narrow end and to pressure-driven flow directed from the narrow end. The nematode is inserted at the conduit's wide end. Directed by the electric field (through electrotaxis), the nematode swims deliberately upstream toward the negative pole of the DC field. As the conduit narrows, the average fluid velocity and the drag force on the nematode increase. Eventually, the nematode arrives at an equilibrium position, at which its propulsive force balances the viscous drag force induced by the adverse flow. The equilibrium position of different animals, with similar body lengths, was measured as a function of the flow rate. The flow field around the nematode was obtained by direct numerical simulations with the experimentally imaged gait and the tapered geometry ...

  16. Intraocular nematode with diffuse unilateral subacute neuroretinitis: case report

    Directory of Open Access Journals (Sweden)

    Zakariah Sakinah

    2011-06-01

    Full Text Available Abstract Background Live intraocular nematode is a rare occurrence. Nematode can migrate actively within the eye, creating visual symptoms and damaging ocular tissue. Case presentation A 26-year old man presented with painless reduced vision of the left eye for one week duration. It was associated with floaters. Visual acuity on the left eye was hand movement. Anterior segment examination was normal with normal intra-ocular pressure. Fundus examination showed a live nematode lying subretinally at the macular area with macular oedema and multifocal chorioretinal lesions at peripheral retina. There was no vitritis, vasculitis or any retinal hemorrhage. Systemic examination revealed normal findings and laboratory studies only showed leucocytosis with normal eosinophil count and negative serum toxocara antibody. The diagnosis of introcular nematode with diffuse unilateral subacute neuroretinitis was made. He was treated with oral anti-helminths and a course of oral steroid at a reducing dose. The nematode had died evidenced by its immobility during the treatment and finally disintegrated, leaving macular oedema with mottling appearance and mild hyperpigmentation. Multifocal chorioretinal lesions had also resolved. However despite treatment his visual acuity during follow-up had remained poor. Conclusions Cases of intraocular nematode, though not commonly encountered, continue to present the ophthalmologist with the problem of diagnosis and management and hence poorer prognosis to the patient.

  17. 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.

  18. Conserved nematode signalling molecules elicit plant defenses and pathogen resistance.

    Science.gov (United States)

    Manosalva, Patricia; Manohar, Murli; von Reuss, Stephan H; Chen, Shiyan; Koch, Aline; Kaplan, Fatma; Choe, Andrea; Micikas, Robert J; Wang, Xiaohong; Kogel, Karl-Heinz; Sternberg, Paul W; Williamson, Valerie M; Schroeder, Frank C; Klessig, Daniel F

    2015-07-23

    Plant-defense responses are triggered by perception of conserved microbe-associated molecular patterns (MAMPs), for example, flagellin or peptidoglycan. However, it remained unknown whether plants can detect conserved molecular patterns derived from plant-parasitic animals, including nematodes. Here we show that several genera of plant-parasitic nematodes produce small molecules called ascarosides, an evolutionarily conserved family of nematode pheromones. Picomolar to micromolar concentrations of ascr#18, the major ascaroside in plant-parasitic nematodes, induce hallmark defense responses including the expression of genes associated with MAMP-triggered immunity, activation of mitogen-activated protein kinases, as well as salicylic acid- and jasmonic acid-mediated defense signalling pathways. Ascr#18 perception increases resistance in Arabidopsis, tomato, potato and barley to viral, bacterial, oomycete, fungal and nematode infections. These results indicate that plants recognize ascarosides as a conserved molecular signature of nematodes. Using small-molecule signals such as ascarosides to activate plant immune responses has potential utility to improve economic and environmental sustainability of agriculture.

  19. Alternatives to anthelmintics for the control of nematodes in livestock.

    Science.gov (United States)

    Stear, M J; Doligalska, M; Donskow-Schmelter, K

    2007-02-01

    Efficient and welfare-friendly livestock production demands the control of nematode infection. Current control measures rely upon anthelmintic treatment but are threatened by the widespread evolution of drug-resistance in parasite populations. Several methods have been advocated to control nematodes without relying on effective anthelmintics. These include grazing management, biological control, nutritional supplementation, vaccination, and genetic approaches. Each method has its advantages and disadvantages. There are several grazing management schemes that can reduce the severity of infection but they are insufficient on their own to control infection. Biological control includes the use of predatory fungi to control nematode populations and the use of pasture species that can reduce the intensity of infection. Fungi can control nematodes but the current requirement for daily feeding means that this approach will be most useful for animals that are handled daily. Feeding supplementary protein can control nematode infection. The method is simple but can be expensive and may not be cost-effective for some marginal enterprises. Genetic approaches include the use of resistant breeds and selective breeding. Some breeds will thrive in conditions that kill animals from other breeds but substitution of resistant breeds is not always feasible. Selective breeding is effective and inexpensive but requires a high level of expertise. The most appropriate method or set of methods to minimize the adverse consequences of nematode infection may vary among farms.

  20. Directional movement of entomopathogenic nematodes in response to electrical fields: Effects of species, magnitude of voltage, and infective juvenile age

    Science.gov (United States)

    Entomopathogenic nematodes respond to a variety of stimuli when foraging. Previously, we reported a directional response to electrical fields for two entomopathogenic nematode species; specifically, when electrical fields were generated on agar plates Steinernema glaseri (a nematode that utilizes a...

  1. Plant nematodes in South Africa. 12. Checklist of plant nematodes of the protected areas of the Eastern Cape Province

    Directory of Open Access Journals (Sweden)

    Mariette Marais

    2014-02-01

    Full Text Available Soil-inhabiting nematodes, including plant-parasitic nematodes, are considered to be the most abundant multicellular organisms in the soil, and of particular interest since they are an integral part of the interlocking chain of nutrient conversions. Because of their abundance and relative susceptibility to both physical and chemical changes, these organisms are used as indicator organisms. The National Collection of Nematodes (NCN consists of a core collection, the Meloidogyne Collection and the Juan Heyns Collection, which are housed at the Plant Protection Research Institute of the Agricultural Research Council in Pretoria. Vast amounts of biodiversity data are contained in NCN, and the digitising of the collection from 2007 to 2014 yielded unpublished locality information, especially datasets of plant nematodes reported from protected areas of the Eastern Cape. Two hundred and thirty plant nematode species belonging to 36 genera were reported from the Eastern Cape. Of these, only 80 were from protected areas, whilst 163 were from uncultivated areas (outside protected areas and 148 from cultivated areas. Ten species were described from protected areas, namely Criconemoides silvicola, Meloinema silvicola, Ogma tuberculatum, Paralongidorus cebensis, Paralongidorus hanliae, Scutellonema tsitsikamense, Trichodorus vandenbergae, Xiphinema erriae, Xiphinema ornatizulu and Xiphinema simplex. Only M. silvicola, O. tuberculatum, P. cebensis and S. tsitsikamense were not reported from other provinces, suggesting endemism.Conservation implications: The diversity of nematode fauna is not adequately protected as most nematode biodiversity in the Eastern Cape lies outside protected areas, with only 80 of the 230 plant-feeding nematode species in the province being reported from protected areas.

  2. Plant-parasitic Nematode Acetylcholinesterase Inhibition by Carbamate and Organophosphate Nematicides.

    Science.gov (United States)

    Opperman, C H; Chang, S

    1990-10-01

    The sensitivity of acetylcholinesterases (ACHE) isolated from the plant-parasitic nematodes Meloidogyne arenaria, M. incognita, and Heterodera glycines and the free-living nematode Caenorhabditis elegans to carbamate and organophosphate nematicides was examined. The AChE from plant-parasitic nematode species were more sensitive to carbamate inhibitors than was AChE from C. elegans, but response to the organophosphates was approximately equivalent. The sulfur-containing phosphate nematicides were poor inhibitors of nematode acetylcholinesterase, but treatment with an oxidizing agent greatly improved inhibition. Behavioral bioassays with living nematodes revealed a poor relationship between enzyme inhibition and expression of symptoms in live nematodes.

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

    Science.gov (United States)

    Dutta, Tushar K.; Papolu, Pradeep K.; Banakar, Prakash; Choudhary, Divya; Sirohi, Anil; Rao, Uma

    2015-01-01

    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. PMID:25883594

  4. 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.

  5. Pan-phylum Comparison of Nematode Metabolic Potential.

    Directory of Open Access Journals (Sweden)

    Rahul Tyagi

    2015-05-01

    Full Text Available Nematodes are among the most important causative pathogens of neglected tropical diseases. The increased availability of genomic and transcriptomic data for many understudied nematode species provides a great opportunity to investigate different aspects of their biology. Increasingly, metabolic potential of pathogens is recognized as a critical determinant governing their development, growth and pathogenicity. Comparing metabolic potential among species with distinct trophic ecologies can provide insights on overall biology or molecular adaptations. Furthermore, ascertaining gene expression at pathway level can help in understanding metabolic dynamics over development. Comparison of biochemical pathways (or subpathways, i.e. pathway modules among related species can also retrospectively indicate potential mistakes in gene-calling and functional annotation. We show with numerous illustrative case studies that comparisons at the level of pathway modules have the potential to uncover biological insights while remaining computationally tractable. Here, we reconstruct and compare metabolic modules found in the deduced proteomes of 13 nematodes and 10 non-nematode species (including hosts of the parasitic nematode species. We observed that the metabolic potential is, in general, concomitant with phylogenetic and/or ecological similarity. Varied metabolic strategies are required among the nematodes, with only 8 out of 51 pathway modules being completely conserved. Enzyme comparison based on topology of metabolic modules uncovered diversification between parasite and host that can potentially guide therapeutic intervention. Gene expression data from 4 nematode species were used to study metabolic dynamics over their life cycles. We report unexpected differential metabolism between immature and mature microfilariae of the human filarial parasite Brugia malayi. A set of genes potentially important for parasitism is also reported, based on an analysis of

  6. Pan-phylum Comparison of Nematode Metabolic Potential.

    Science.gov (United States)

    Tyagi, Rahul; Rosa, Bruce A; Lewis, Warren G; Mitreva, Makedonka

    2015-05-01

    Nematodes are among the most important causative pathogens of neglected tropical diseases. The increased availability of genomic and transcriptomic data for many understudied nematode species provides a great opportunity to investigate different aspects of their biology. Increasingly, metabolic potential of pathogens is recognized as a critical determinant governing their development, growth and pathogenicity. Comparing metabolic potential among species with distinct trophic ecologies can provide insights on overall biology or molecular adaptations. Furthermore, ascertaining gene expression at pathway level can help in understanding metabolic dynamics over development. Comparison of biochemical pathways (or subpathways, i.e. pathway modules) among related species can also retrospectively indicate potential mistakes in gene-calling and functional annotation. We show with numerous illustrative case studies that comparisons at the level of pathway modules have the potential to uncover biological insights while remaining computationally tractable. Here, we reconstruct and compare metabolic modules found in the deduced proteomes of 13 nematodes and 10 non-nematode species (including hosts of the parasitic nematode species). We observed that the metabolic potential is, in general, concomitant with phylogenetic and/or ecological similarity. Varied metabolic strategies are required among the nematodes, with only 8 out of 51 pathway modules being completely conserved. Enzyme comparison based on topology of metabolic modules uncovered diversification between parasite and host that can potentially guide therapeutic intervention. Gene expression data from 4 nematode species were used to study metabolic dynamics over their life cycles. We report unexpected differential metabolism between immature and mature microfilariae of the human filarial parasite Brugia malayi. A set of genes potentially important for parasitism is also reported, based on an analysis of gene expression in

  7. Geologic Features and Feasibility Test Technologies of Guizhou Qianbei Pinewood Molybdenum-Nickel Minerals%贵州黔北松林钼镍矿地质特征及可行性试验技术

    Institute of Scientific and Technical Information of China (English)

    沈大兴; 杨山福; 樊正烈; 王安科

    2015-01-01

    贵州松林钼镍矿主要产于下寒武统牛蹄塘组(∈1n)底部“磷块岩(上磷层)之上的金属层”,已有多年钼镍矿的开发历史,结合矿石的结构构造和矿石类型,采用镍钼矿→回转窖焙烧→碱浸→除杂→离子交换→酸沉→烘干→钼酸铵工艺生产钼酸铵产品,同时采用富镍渣→制粒→熔炼→低镍锍工艺处理浸出渣生产低镍锍,并使弃渣无害化,这对区内钼矿开发一定会取得良好的经济效益和社会效益。%The Guizhou Pinewood molybdenum-nickel minerals are chiefly generated on “a metal layer above the phosphorite (upper phosphor layer)” at the bottom of the lower Cambrian Niutitang formation (∈1n). It has many years of molybdenum-nickel minerals-developing history. Ammonium molybdate products are produced with such process as molybdenum minerals→rotary kiln roasting→alkaline leaching→decontamination→ion exchange→acid precipitation→drying-ammonium molybdate production technology and meantime low-nickel mattes are produced by dealing with the leaching residues through the process of preparing nickel-rich residues→pelletizing→smelting based on ore structures and types. In addition, the waste slag is made harmless. This will undoubtedly bring economic and social benefits to the exploration of molybdenum-nickel minerals.

  8. 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...

  9. Current Status of Soil-transmitted Nematode Infection in China

    Institute of Scientific and Technical Information of China (English)

    YING-DAN CHEN; LIN-HUA TANG; LONG-QI XU

    2008-01-01

    Objective To Carry out national surveys for ascertaining the current status and trends of soil-transmitted nematode infections in China,providing scientific basis for forther developing control strategies.Methods In 1988-1992(hereinafter abbreriated as "survey in 1990"),a stratified cluster random sampling method was used in the survey.In 2001-2004(hereinafter abbreriated as "survey in 2003"),in order to compare with the survey in 1990,two-characteristic stratified cluster random sampling method was used and 687 investigation spots were sampled from the 2848 spots selected in the survey in 1990.Kato-Katz thick smear method was used to examine the eggs of soil-transmitted nematodes in fecal samples. Results The prevalence rates were 53.6% and 19.6% for soil-transmitted nematodes,14.6%and 6.120% for hookworms,44.6% and 12.7% for Ascaris lumbricoides,17.4% and 4.630% for Trichuris trichiura in survey 1990 and survey 2003,respectively.The prevalence rates of soil-transmitted nematodes were higher in 13 provinces than the average level in China in the survey in 1990.and higher in 8 provinces than the average level in the survey in 2003.The prevalence of hookworms,Ascaris lumbricoides,Trichurls trichiura and the overall prevalence of soft-transmitted nematodes were higher in females than in males.It is estimated from the results of survey in 2003 that the number of persons with soil-transmitted nematode infections in the country is about 129 million,less than that in the survey in 1990. Conclusion The prevalence of soil-transmitted nematodes has declined considerably but is still relatively high in some provinces and autonomous regions.Control activities and socioeconomic development may have contributed to the decreased prevalence.

  10. GABA localization in the nematode Ascaris

    Energy Technology Data Exchange (ETDEWEB)

    Guastella, J.

    1988-01-01

    A histochemical approach was used to examine the distribution of GABA-associated neurons in the nematode Ascaris, an organism whose small number of morphologically simple neurons make it an excellent preparation for analyzing neuronal phenotypes. Two GABAergic markers were examined: GABA-like immunoreactivity (GLIR), a marker for endogenous stores of GABA; and ({sup 3}H)-GABA uptake, a marker for GABA uptake sites. Strong GLIR was present in the cell bodies, neurites and commissures of dorsal and ventral inhibitory motorneurons present in this region. Strong GLIR was also present in the cell bodies and processes of the four RME neurons in the nerve ring and in several other ganglionic neurons. Staining was absent in excitatory motorneurons, in ventral cord interneurons and in muscle cells and hypodermis. GABA uptake sites were found in single neural processes in both the ventral and dorsal nerve cords. ({sup 3}H)-GABA labeling was also observed in the other two RME cells and several other cephalic neurons. Four putative cholinergic excitatory motorneurons in the retrovesicular ganglion (RVG) were heavily labeled. Ventral and dorsal nerve cord inhibitory motorneurons did not take up ({sup 3}H)-GABA. Labeling of the ventral cord excitatory motorneuron somata and cell bodies was at or slightly above background. Heavy labeling of muscle cells was also observed.

  11. Checklist of free-living nematode species in the transitional environment of Lake Varano (Southern Italy)

    National Research Council Canada - National Science Library

    Semprucci, F; Balsamo, M

    2015-01-01

    ...–living nematode species in Lake Varano, Southern Adriatic Sea, Italy. The nematode community was mainly composed of species typical of fine sediments that usually prevail in transitional environments (TE...

  12. Phenotypic and molecular evaluation of cotton hairy roots as a model system for studying nematode resistance

    Science.gov (United States)

    The cellular mechanisms that mediate resistance of allotetraploid cotton (Gossypium spp.) to root-knot nematode (Meloidogyne incognita) and reniform nematode (Rotylenchulus reniformis) are poorly understood. Here, Agrobacterium rhizogenes-induced hairy roots were investigated as a possible research...

  13. Taxonomy, morphology and phylogenetics of coffee-associated root-lesion nematodes, Pratylenchus spp

    Science.gov (United States)

    Technical Abstract: Although lesion nematodes (Pratylenchus species) can reduce coffee yield worldwide, methods for their identification are often difficult to implement. This review summarizes the diagnostic morphological features for distinguishing the eight previously described lesion nematode sp...

  14. 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.

  15. Predation rates and prey selectivity in two predacious estuarine nematode species

    NARCIS (Netherlands)

    Moens, T.; Herman, P.M.J.; Verbeeck, L.; Steyaert, M.; Vincx, M.

    2000-01-01

    Enoploides longispiculosus and Adoncholaimus fuscus are representatives of nematode genera prominent in sediments of the North Sea and adjacent estuaries. Both are predatory nematodes, although predation is facultative in the latter. The present study investigates functional responses and prey

  16. 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.

  17. 松材线虫体表物质与其携带细菌的关系%The relationship between substance on the pine wood nematode body surface and bacteria carried by the nematode

    Institute of Scientific and Technical Information of China (English)

    贲爱玲; 戚建光; 张宏娟; 陈玲; 韩正敏

    2011-01-01

    Pine wilt disease was complex infection caused by pine wood nematode ( Bursaphelenchus xylophilus) , and bacteria. Studying the relationship between B. Xylophilus and bacteria may provide evidence for the pathogenic mechanism of pine wilt disease. To clarify the relationship, the bacterial strains were inoculated to marinade on different aseptic B. Xylophilus surface body surface, and cultured aseptic B. Xylophilus after added the bacteria was to the B. Xylophilus suspension. The results showed that the reproduction of bacteria was stimulated by the marinade of B. Xylophilus body surface, B. Xylophilus numbers increased more rapidly with bacteria present than without bacteria. This revealed that the reproduction and growth of B. Xylophilus was also promoted by the bacteria. In conclusion, B. Xylophilus and the bacteria benefited each other. Experiments were also designed to investigate the tropism test of aseptic B. Xylophilus and bacteria, and test the specificity between the B. Xylophilus and bacteria it carried. The results indicated that the bacterial strain of P. Agglomerans or the bacterial strain mixed with P. Agglomerans had obvious taxis towards all isolates of aseptic B. Xylophilus. Experiments also tested the specificity between the B. Xylophilus and bacteria it carried. The results showed that the aseptic B. Xylophilus has no taxis towards the bacteria it carried, and that there was no obvious specificity taxis to the B. Xylophilus with the bacterial strains it carried.%松萎蔫病是由松材线虫与其所携带的细菌复合侵染所引起.为进一步明确松材线虫与其携带细菌的关系,笔者用无菌线虫体表浸泡物处理细菌,再将无菌线虫各虫株与细菌共培养,结果表明细菌的存在可促进线虫的繁殖,线虫体表浸泡物质可促进细菌繁殖,无菌线虫与细菌共培养后线虫繁殖数量较无菌线虫单独培养有明显增加,说明松材线虫与其体表细菌的关系为一

  18. Nematodes as bioindicators of soil degradation due to heavy metals.

    Science.gov (United States)

    Šalamún, Peter; Renčo, Marek; Kucanová, Eva; Brázová, Tímea; Papajová, Ingrid; Miklisová, Dana; Hanzelová, Vladimíra

    2012-11-01

    The effect of distance from a heavy metal pollution source on the soil nematode community was investigated on four sampling sites along an 4 km transect originating at the Kovohuty a.s. Krompachy (pollution source). The soil nematode communities were exposed to heavy metal influence directly and through soil properties changes. We quantified the relative effects of total and mobile fraction of metals (As, Cd, Cr, Cu, Pb, and Zn) on soil ecosystem using the nematode community structure (trophic and c-p groups,) and ecological indices (Richness of genera, H', MI2-5, etc.). Pollution effects on the community structure of soil free living nematodes was found to be the highest near the pollution source, with relatively low population density and domination of insensitive taxa. A decrease in heavy metals contents along the transect was linked with an increase in complexity of nematode community. The majority of used indices (MI2-5, SI, H') negatively correlated (P bioindication of contamination and could be used as an alternative to the common approaches based on chemical methods.

  19. Plant genes involved in harbouring symbiotic rhizobia or pathogenic nematodes.

    Science.gov (United States)

    Damiani, Isabelle; Baldacci-Cresp, Fabien; Hopkins, Julie; Andrio, Emilie; Balzergue, Sandrine; Lecomte, Philippe; Puppo, Alain; Abad, Pierre; Favery, Bruno; Hérouart, Didier

    2012-04-01

    The establishment and development of plant-microorganism interactions involve impressive transcriptomic reprogramming of target plant genes. The symbiont (Sinorhizobium meliloti) and the root knot-nematode pathogen (Meloidogyne incognita) induce the formation of new root organs, the nodule and the gall, respectively. Using laser-assisted microdissection, we specifically monitored, at the cell level, Medicago gene expression in nodule zone II cells, which are preparing to receive rhizobia, and in gall giant and surrounding cells, which play an essential role in nematode feeding and constitute the typical root swollen structure, respectively. We revealed an important reprogramming of hormone pathways and C1 metabolism in both interactions, which may play key roles in nodule and gall neoformation, rhizobia endocytosis and nematode feeding. Common functions targeted by rhizobia and nematodes were mainly down-regulated, whereas the specificity of the interaction appeared to involve up-regulated genes. Our transcriptomic results provide powerful datasets to unravel the mechanisms involved in the accommodation of rhizobia and root-knot nematodes. Moreover, they raise the question of host specificity and the evolution of plant infection mechanisms by a symbiont and a pathogen.

  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.

  1. Nematode Chemotaxis: Gradual Turns, Sharp Turns, and Modulated Turn Angles

    Science.gov (United States)

    Patel, Amar; Padmanabhan, Venkat; Rumbaugh, Kendra; Vanapalli, Siva; Blawzdziewicz, Jerzy

    2013-03-01

    We examine strategies used by the soil-dwelling nematode Caenorhabditis Elegans for chemotaxis in complex environments. The proposed description is based on our recently developed piecewise-harmonic-curvature model of nematode locomotion [PLoS ONE, 7(7) e40121 (2012)], where random harmonic-curvature modes represent elementary locomotory movements. We show that the previously described gradual-turn and sharp-turn chemotaxis strategies can be unified in our model. The gradual-turn mechanism relies on crawling amplitude changes commensurate with the undulation frequency. The sharp-turn mechanism consists in modulation of the frequency of jumps to large-amplitude modes. We hypothesize that there exists a third strategy, where the nematode adjusts the variance of the amplitude distribution. Such adjustments result in a modulation of the magnitude of random turns, with smaller turns performed when the nematode moves toward the increasing chemoatractant concentration. Experiments are proposed to determine if the third strategy is present in the nematode behavior. This work was supported by NSF grant No. CBET 1059745.

  2. The collective motion of nematodes in a thin liquid layer

    CERN Document Server

    Gart, Sean; Jung, Sunghwan

    2010-01-01

    Many organisms live in confined fluidic environments such as the thin liquid layers on the skin of host organisms or in partially- saturated soil. We investigate the collective behaviour of nematodes in a thin liquid layer, which was first observed by Gray and Lissmann, [J. Exp. Biol. 41, 135 (1964)]. We show experimentally that nematodes confined by a thin liquid film come into contact and only separate again after some intervention. We attribute this collective motion to an attractive force between them arising from the surface tension of the layer and show that for nearby nematodes this force is typically stronger than the force that may be exerted by the nematodes' muscles. We believe this to be the first demonstration of the "Cheerios effect" acting on a living organism. However, we find that being grouped together does not significantly alter the body stroke and kinematic performance of the nematode: there are no statistically significant changes of the Strouhal number and the ratio of amplitude to wave...

  3. On the cultivation of free-living marine and estuarine nematodes

    OpenAIRE

    T. Moens; Vincx, M.

    1998-01-01

    Although a large body of literature exists on the systematics and ecology of free-living marine and brackish-water nematodes, key questions on the nature and magnitude of interactions between nematodes and other organisms in the benthos remain unanswered. Relatively few authors have investigated live nematodes in food web studies or in experiments dealing with the nematodes' response to a varying environment. It is mainly for the latter purpose that attempts have been made to maintain, rear a...

  4. Microsatellites of the parasitic nematode Haemonchus contortus: polymorphism and linkage with a direct repeat

    NARCIS (Netherlands)

    Hoekstra, R.; Criado-Fornelio, A.; Fakkeldij, J.; Bergman, J.; Roos, M.H.

    1997-01-01

    To develop tools to analyse parasitic nematode population structures and the effects of selection pressure on the nematode population, we isolated and characterised 13 microsatellite markers of the nematode Haemonchus contortus. The density of CA/GT microsatellites, once in 575 kb, is lower than in

  5. Trapping of root-knot nematodes by the adhesive hyphae-forming fungus Arthrobotrys oligospora.

    NARCIS (Netherlands)

    den Belder, E.

    1994-01-01

    The present study addresses the ecology of a particular isolate of Arthrobotrys oligospora (CBS 289.82) in relation to its efficacy in controlling the root-knot nematode, Meloidogyne hapla.This isolate was selected because it differs from most nematode-trapping fungi in that it captures nematodes wi

  6. 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...

  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. 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...

  9. Microbial ecology and nematode control in natural ecosystems. Building coherence between microbial ecology and molecular mechanisms

    NARCIS (Netherlands)

    Costa, S.R.; Putten, van der 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

  10. Towards isolation of the tomato root-knot nematode resistance gene Mi via positional cloning.

    NARCIS (Netherlands)

    Daelen, van R.A.J.J.

    1995-01-01

    Root-knot nematodes of the genus Meloidogyne are severe pathogens of plants and worldwide they cause damage to many economically important crops like potato, rice, cotton, and tomato. So the control of nematodes and the protection of plants against nematode damage are matters of major concern. Some

  11. Microbial ecology and nematode control in natural ecosystems. Building coherence between microbial ecology and molecular mechanisms

    NARCIS (Netherlands)

    Costa, S.R.; Putten, van der 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 cyclin

  12. [Effect of agrochemicals and bio-control productions on soil nematode community dynamics].

    Science.gov (United States)

    Zhang, Wanmin; Duan, Yuxi; Chen, Lijie; Liang, Chen

    2002-05-01

    Dynamics of soil nematode communities amended with agrochemicals and bio-control preparations were investigated in a soybean field. The results showed that the frequency of plant non-parasitic nematodes were obviously higher in soil amended with bio-control preparations (Doufeng 1) than with urea and herbicide, however, that of plant parasitic nematodes exhibited an inverse trend.

  13. 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.

  14. Extraintestinal nematode infections of red foxes (Vulpes vulpes) in Hungary.

    Science.gov (United States)

    Sréter, T; Széll, Z; Marucci, G; Pozio, E; Varga, I

    2003-08-14

    A survey was carried out to investigate the prevalence and worm burden of extraintestinal nematodes in 100 red foxes (Vulpes vulpes) of Hungary. The overall prevalence of nematode infections of the respiratory tract was 76%. Eucoleus aerophilus (Capillaria aerophila) was the predominant species (66%), followed by Crenosoma vulpis (24%), Eucoleus (Capillaria) böhmi (8%) and Angiostrongylus vasorum (5%). Pearsonema (Capillaria) plica was found in 52% of the urinary bladders. In 3% of the foxes, Trichinella britovi was present in muscle samples. The high prevalence of lungworms and P. plica and the fox colonisation in urban areas may enhance the prevalence of these nematode infections in domestic dogs and cats, and the flow of T. britovi from the sylvatic cycle to the domestic cycle, enhancing the risk of infections in humans.

  15. Nematodes of elasmobranch fishes from the southern coast of Brazil

    Directory of Open Access Journals (Sweden)

    Marcelo Knoff

    2001-01-01

    Full Text Available New records for nematode species recovered from elasmobranch fishes in Brazil are established and new systematical arrangements proposed. Parascarophis sphyrnae Campana-Rouget, 1955 from the spiral valve of Sphyrna zygaena is referred for the first time in South America as a new host record. Procamallanus (S. pereirai Annereaux, 1946, from the spiral valve of Raja castelnaui is reported parasitizing an elasmobranch host. Nematode larvae of the genera Anisakis, Contracaecum, Pseudoterranova and Raphidascaris are listed from the stomach and spiral valves of several hosts. Anisakidae larvae previously referred in Brazil in the genus Phocanema should be reallocated in Pseudoterranova. Nematodes of the genera Anisakis, Contracaecum, Pseudoterranova and Raphidascaris are reported for the first time parasitizing elasmobranchs in Brazil.

  16. The development of RNA interference (RNAi) in gastrointestinal nematodes.

    Science.gov (United States)

    Selkirk, Murray E; Huang, Stanley C; Knox, David P; Britton, Collette

    2012-04-01

    Despite the utility of RNAi for defining gene function in Caenorhabditis elegans and early successes reported in parasitic nematodes, RNAi has proven to be stubbornly inconsistent or ineffective in the animal parasitic nematodes examined to date. Here, we summarise some of our experiences with RNAi in parasitic nematodes affecting animals and discuss the available data in the context of our own unpublished work, taking account of mode of delivery, larval activation, site of gene transcription and the presence/absence of essential RNAi pathway genes as defined by comparisons to C. elegans. We discuss future directions briefly including the evaluation of nanoparticles as a means to enhance delivery of interfering RNA to the target worm tissue.

  17. 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.

  18. Efficacy of extracts of immature mango on ovine gastrointestinal nematodes.

    Science.gov (United States)

    Nery, Patrícia S; Nogueira, Flávia A; Oliveira, Neide J F; Martins, Ernane R; Duarte, Eduardo R

    2012-12-01

    The principal health problem in small ruminants is helminthiasis and the rapid development of nematode resistance to anthelminthics has limited the success of control in several countries, stimulating the search for alternatives. In this study, extracts of immature fruits of the mango Mangifera indica L. var Ubá were evaluated for inhibition of larval development and fecal egg count reduction in sheep naturally infected with gastrointestinal nematodes. In the phytochemical analyses, tannins and flavonoids were the metabolites identified. Aqueous extracts of immature fruits at 100 mg ml(-1) showed 100 % inhibition of larval development. The LC(90) of the extract was 35.9 mg ml(-1) and the in vivo anthelminthic efficacy at 0.740 g kg(-1) (BW, orally) was 53 %. The identification of larvae showed that 99.8 % were Haemonchus spp. In vitro and in vivo results indicate that this fruit could assist ovine nematode control.

  19. Caenorhabditis elegans: A Genetic Guide to Parasitic Nematode Biology.

    Science.gov (United States)

    Bird, D M; Opperman, C H

    1998-09-01

    The advent of parasite genome sequencing projects, as well as an increase in biology-directed gene discovery, promises to reveal genes encoding many of the key molecules required for nematode-host interactions. However, distinguishing parasitism genes from those merely required for nematode viability remains a substantial challenge. Although this will ultimately require a functional test in the host or parasite, the free-living nematode Caenorhabditis elegans can be exploited as a heterologous system to determine function of candidate parasitism genes. Studies of C. elegans also have revealed genetic networks, such as the dauer pathway, that may also be important adaptations for parasitism. As a more directed means of identifying parasitism traits, we developed classical genetics for Heterodera glycines and have used this approach to map genes conferring host resistance-breaking phenotypes. It is likely that the C. elegans and H. glycines genomes will be at least partially syntenic, thus permitting predictive physical mapping of H. glycines genes of interest.

  20. 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

  1. Studies onPaecilomyces marquandii from nematode suppressive chinampa soils.

    Science.gov (United States)

    Marban-Mendoza, N; Garcia-E, R; Dicklow, M B; Zuckerman, B M

    1992-05-01

    Two applications of isolates ofPaecilomyces marquandii from suppressive chinampa soils or P. lilacinus from Peru, fungi that parasitize nematode eggs, generally gave better control of tomato root-knot due toMeloidogyne incognita than did a single application. The effects on root galling by each of thePaecilomyces isolates varied between experiments; however, the ovicidal potential of the three isolates did not differ significantly. Proteins specific for each of the isolates were demonstrated by SDS gel electrophoresis. The results indicate thatP. marquandii is one of the natural soil organisms that contribute to nematode suppression in the chinampa agricultural soils.

  2. An evolutionary perspective on gastrointestinal nematodes of sheep.

    Science.gov (United States)

    Stear, M J; Singleton, D; Matthews, L

    2011-06-01

    The purpose of this paper was to discuss from an evolutionary perspective the interaction between domestic sheep (Ovis aries) and their gastrointestinal nematodes. Although evolution is the central theme of biology, there has been little attempt to consider how evolutionary forces have shaped and continue to shape the relationships between domestic animals and their parasite community. Mathematical modelling of the host-parasite relationship indicated that the system is remarkably robust to perturbations in its parameters. This robustness may be a consequence of the long coevolution of host and parasites. Although nematodes can potentially evolve faster than the host, coevolution is not dominated by the parasite and there are several examples where breeds of cattle or sheep have evolved high levels of resistance to disease. Coevolution is a more equal partnership between host and nematode than is commonly assumed. Coevolution between parasites and the host immune system is often described as an arms race where both host immune response genes and parasite proteins evolve rapidly in response to each other. However, initial results indicate that nematode antigens are not evolving rapidly; the arms race between the immune system and nematodes, if it exists, is happening very slowly. Fisher's fundamental theorem of natural selection states that genes with positive effects on fitness will be fixed by natural selection. Consequently, heritable variation in fitness traits is expected to be low. Contrary to this argument, there is considerable genetic variation in resistance to nematode infection. In particular, the heritabilities of nematode-specific IgA and IgE activity are moderate to high. The reasons for this apparent violation of the fundamental theorem of natural selection are not clear but several possible explanations are explored. Faecal nematode egg counts increase at the beginning of the grazing season - a phenomenon known as the periparturient rise. This

  3. 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.

  4. ORGANIC VS CONVENTIONAL: SOIL NEMATODE COMMUNITY STRUCTURE AND FUNCTION.

    Science.gov (United States)

    Kapp, C; Storey, S G; Malan, A P

    2014-01-01

    Global increases in human population are creating an ever-greater need for food production. Poor soil management practices have degraded soil to such an extent that rapidly improved management practices is the only way to ensure future food demands. In South Africa, deciduous fruit producers are realising the need for soil health, and for an increased understanding of the benefits of soil ecology, to ensure sustainable fruit production. This depends heavily on improved orchard management. Conventional farming relies on the addition of artificial fertilizers, and the application of chemicals, to prevent or minimise, the effects of the soil stages of pest insects, and of plant-parasitic nematodes. Currently, there is resistance toward conventional farming practices, which, it is believed, diminishes biodiversity within the soil. The study aimed to establish the soil nematode community structure and function in organically, and conventionally, managed deciduous fruit orchards. This was done by determining the abundance, the diversity, and the functionality of the naturally occurring free-living, and plant-parasitic, nematodes in deciduous fruit orchards in the Western Cape province of South Africa. The objective of the study was to form the basis for the use of nematodes as future indicators of soil health in deciduous fruit orchards. Orchards from neighbouring organic, and conventional, apricot farms, and from an organic apple orchard, were studied. All the nematodes were quantified, and identified, to family level. The five nematode-classified trophic groups were found at each site, while 14 families were identified in each orchard, respectively. Herbivores were dominant in all the orchards surveyed. Organic apples had the fewest herbivores and fungivores, with the highest number of carnivores. When comparing organic with conventional apricot orchards, higher numbers of plant-parasitic nematodes were found in the organic apricot orchards. The Maturity Index (MI

  5. Root - knot nematodes on summer vegetables in North Tunisia

    Directory of Open Access Journals (Sweden)

    Moens, M.

    1985-01-01

    Full Text Available The influence of different factors on the root-knot nematode infestation and on the yield of tomato have been examined : date of planting, cultivar choice, rotation scheme and soil disinfestation. It was found that the earliest planting date gave the highest yield but also the most severe root galling on susceptible tomato cultivars. A cropping sequence where wheat is alternated with tomatoes was not sufficient for reducing root-knot nematode population to a level permitting the cropping of a susceptible tomato cultivar. Long rotations with non host crops should be used. Soil treatment with certain nematicides significantly reduced the root galling and improved the yield.

  6. 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.

  7. 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.

  8. 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.

  9. The activation and suppression of plant innate immunity by parasitic nematodes.

    Science.gov (United States)

    Goverse, Aska; Smant, Geert

    2014-01-01

    Plant-parasitic nematodes engage in prolonged and intimate relationships with their host plants, often involving complex alterations in host cell morphology and function. It is puzzling how nematodes can achieve this, seemingly without activating the innate immune system of their hosts. Secretions released by infective juvenile nematodes are thought to be crucial for host invasion, for nematode migration inside plants, and for feeding on host cells. In the past, much of the research focused on the manipulation of developmental pathways in host plants by plant-parasitic nematodes. However, recent findings demonstrate that plant-parasitic nematodes also deliver effectors into the apoplast and cytoplasm of host cells to suppress plant defense responses. In this review, we describe the current insights in the molecular and cellular mechanisms underlying the activation and suppression of host innate immunity by plant-parasitic nematodes along seven critical evolutionary and developmental transitions in plant parasitism.

  10. Breeding Soybeans for Resistance to Physiological Race 4 of Cyst Nematode

    Institute of Scientific and Technical Information of China (English)

    WANG Lian-zheng; WANG Lan; YAN Qing-shang; ZHAO Rong-juan; CHEN Pin-san; LI Qiang

    2002-01-01

    Soybean cyst nematode causes serious damage to soybean production. In 1991, we started breeding studies on the resistance of soybeans to the cyst nematode. We found that near the Beijing area the dominant race of the cyst nematode was race 4. We made more than 50 combinations of cross. The best combination was Dan 8 × PI 437654 which resulted in marked segregation in plant height, pod habit, resistance to cyst nematode and maturity. We obtained many new soybean lines highly resistant to the cyst nematode through the pedigree method of selection, enlarging the number of plants of good combinations, alternative breeding in the North and in the South, and identification at an early generation. We now have released three soybean cultivars, Zhonghuang 12, Zhonghuang 13 and Zhonghuang 17 with moderate resistance to the cyst nematode in Beijing, Anhui, Tianjin and Northern China. In addition, we obtained many lines which were highly resistant to the cyst nematode.

  11. Screening and identifying cellulose degrading bacteria associated with Bursaphelenchus xylophilus and cloning corresponding genes%松材线虫伴生菌中产纤维素酶细菌的筛选、鉴定及其相关基因的克隆

    Institute of Scientific and Technical Information of China (English)

    牛秋红; 张林; 褚学英; 杜风光; 冯文生; 惠丰立; 柯涛; 樊永欣

    2012-01-01

    To screen, identify bacterial strains with high capability to degrade cellulose from bacteria associated with Bursaphelenchus xylophilus and to clone related genes. [Methods] First, we collected B. xylophilus samples from pine wood nematode disease areas in Nanyang, Henan province, China. Then, we obtained the bacterial strains with high cellulase activities by primarily screening according to Congo red plate methods. The bacterial strain was classified by phenotypic and genotypic characteristics. We designed degenerate primes according to the known endoglucanase gene sequences in GenBank to carry out PCR, and analyzed the cloned sequence. [Results] We obtained seven bacterial strains with high cellulase activities. Among them, the bacterial strain numbered C8 showed the highest cellulase activities. The bacterium was classified to be Enterobacter genus. The full length of a cellulase gene cDNA (1104 bp) (GenBank JQ845065) coding region was successfully cloned. The homogeneous analysis demonstrated that the deduced nucleotide and amino acid of the gene separately shared 97% and 92% with the cellulase from E. aerogenes KCTC 2190, and 82% with the endo-1,4-D-glucanase gene from Klebsiella pneumoniae, and 82% with the a cellulase gene from unculturable bacteria. [Conclusion] It was a novel cellulose gene cloned from B. xylophilus associated bacteria.%[目的]从松材线虫伴生菌中筛选出高效降解纤维素的细菌菌株,初步鉴定后,对其相应的纤维素酶基因尝试克隆.[方法]首先从河南南阳松材线虫病疫区采集到的木材样本中,分离获得松材线虫.采用刚果红平板初筛法,从松材线虫伴生菌中获得具有分泌较高活性纤维素酶的细菌菌株.基于该菌株的形态学、生理学及16 s rDNA序列特征等对高活性菌株进行分类鉴定.设计兼并引物,从高活性菌株中克隆该菌株的纤维素酶基因,并进行序列分析.[结果]获得7株具有分泌较高活性纤维素酶的细菌

  12. 抗松材线虫病赤松家系的抗性测定及组织病理学观察%Resistance Determination and Histopathological Observation of Induced Pinus densiflora Families from Japan to Bursaphelenchus xylophilus

    Institute of Scientific and Technical Information of China (English)

    张艺; 吴小芹; 王钰; 叶建仁

    2007-01-01

    对自日本引进的赤松(Pinus densiflora)27个抗病家系进行人工抗病性测定,结果发现抗病各家系对3个不同来源的松材线虫(Bursaphelenchus xylophilus)虫株都表现出不同程度的抗病性,且差异明显.综合3次接种试验结果发现,引进赤松中有13个家系(1、4、5、6、7、8、13、14、15、17、20、23和25 号)抗病表现较好.对5号抗病家系接种松材线虫后,分别按时间进程(4、8、12、24、36、48、72、96、120 h)进行茎段取样,组织病理学观察发现松材线虫在引进的抗病赤松体内的迁移速度较普通赤松慢,且松树茎内木射线细胞和树脂道泌脂细胞周围的薄壁细胞出现病变较普通赤松晚,病变程度也比普通赤松轻.

  13. Species and their dispersal ability of Monochamus as vectors to transmit Bursaphelenchus xylophilus%松材线虫媒介昆虫种类及其扩散能力

    Institute of Scientific and Technical Information of China (English)

    张建军; 张润志; 陈京元

    2007-01-01

    松材线虫Bursaphelenchus xylophilus是世界性的外来入侵生物,主要依靠媒介昆虫的携带在自然界中扩散传播.能够携带松材线虫的昆虫有45种,而其中可作为媒介昆虫的有13种,全部为墨天牛属Monochamus种类,它们是:松墨天牛M. alternatus,云杉花墨天牛M. saltuarius,卡罗莱纳墨天牛M. carolinensis,加洛墨天牛M.galloprobincialis,白点墨天牛M. scutellatus,南美墨天牛M. titillator,钝角墨天牛M. botusus,香枞墨天牛M. marmorator,墨点墨天牛M. notatus,松墨斑墨天牛M. mutator,粗点墨天牛M. clamator,巨墨天牛M. grandis和云杉小墨天牛M. sutor.由于松墨天牛、云杉花墨天牛和卡罗莱纳墨天牛等3种昆虫在补充营养及产卵初期2个阶段的飞行能力均较强,通常一次飞行可以达到1 000 m左右,因而成为松材线虫的主要传播媒介.表2参33

  14. 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 macroparasite

  15. 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

  16. Root-knot nematode resistant rootstocks for grafted watermelon

    Science.gov (United States)

    Rootstock lines of wild watermelon (Citrullus lanatus var. citroides) with resistance to root-knot nematodes (RKN) were developed by our team at the U.S. Vegetable Laboratory. Rootstock lines RKVL 301, RKVL 316, and RKVL 318 (RKVL = Root Knot Vegetable Laboratory) were compared to wild tinda (Praec...

  17. 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.

  18. Transposon associated markers for the parasitic nematode Haemonchus contortus

    NARCIS (Netherlands)

    Hoekstra, R.; Otsen, M.; Tibben, J.; Lenstra, J.A.; Roos, M.H.

    2000-01-01

    We have previously characterized a Tc1-like transposable element Hctc1, from the parasitic nematode Haemonchus contortus. Here we describe the genetic variation of Hctc1 insertion sites in H. contortus populations differing in geographical origin, resistance to chemotherapeutics and level of inbreed

  19. Phytoparasitic nematodes associated with three types of blueberries in arkansas.

    Science.gov (United States)

    Clark, J R; Robbins, R T

    1994-12-01

    Research and commercial blueberry plantings were sampled in October 1991 to determine the population densities and species of phytoparasitic nematodes associated with rabbiteye (Vaccinium ashei), southern highbush (Vaccinium sp.), and highbusb (V. corymbosum) blueberry cultivars and the sod middles between the blueberry rows. In the research planting at Clarksville, Arkansas, samples from the highbush cv. Bluecrop, the southern highbush cv. Cooper and Gulf Coast, and the sod middles had similar numbers of total vermiform phytoparasitic nematodes (125-451/250 cm(3) soil), whereas the samples from rabbiteye cv. Climax and Tifblue had significantly lower numbers (4/250 cm(3)). The major nematode species associated with blueberries and sod was Xiphinema americanum. In a research planting at Bald Knob, Arkansas, which contained Bluecrop and rabbiteye cultivars only, samples from Bluecrop and the sod had similar numbers (288 and 334/250 cm(3)), and the rabbiteye samples had significantly lower numbers (6-14/250 cm(3)). Xiphinema americanum was the major species found in the blueberry samples, whereas Mesocriconema ornata was the major species in the sod. Nematode population densities and species distribution in commercial rabbiteye plantings in nine counties in central and southwestern Arkansas varied greatly. The average population density for rabbiteye samples was 129/250 cm(3) and for sod was 577/250 cm(3). Weed infestations in the blueberry rows in the commercial plantings probably increased the population size and species distribution.

  20. 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...

  1. Putatively novel sources of resistance to soybean cyst nematode

    Science.gov (United States)

    Soybean cyst nematode (SCN) remains to be the most economically devastating endo-root parasite of soybean [Glycine max L. (Merrill)], in the USA and worldwide. Currently, two resistance loci, rhg1 and Rhg4 have been the main sources of resistance to SCN. Over 95% of soybean cultivars with SCN resist...

  2. IMMUNE REGULATING ES-PRODUCTS IN PARASITIC NEMATODES

    DEFF Research Database (Denmark)

    Bahlool, Qusay Zuhair Mohammad; Buchmann, Kurt; Kania, Per Walter;

    Excretory/secretory (ES) products are molecules including various proteins produced by parasitic nematodes including larval A. simplex which is occurring in numerous marine fish hosts. The function of these substances and their effect on host physiology has not been fully described. The present...

  3. Inducible antibacterial defence in the plant parasitic nematode Meloidogyne artiellia.

    Science.gov (United States)

    Fanelli, Elena; Dileo, Caterina; Di Vito, Mauro; De Giorgi, Carla

    2008-04-01

    Animals and plants both respond rapidly to pathogens by inducing the expression of defence-related genes. Within this context, a prominent role has been assigned to the lysozyme. In the present study we isolated and carried out detailed analysis of the lysozyme gene in the plant nematode Meloidogyne artiellia. The expression of lysozyme was up-regulated following exposure of M. artiellia juveniles to the Gram-negative bacterium Serratia marcescens. On the other hand, when isolated eggs containing embryos at various developmental stages were challenged with bacteria, no increase in lysozyme expression was detected. Evidence of lysozyme expression regulation was obtained in the case of adult male and females worms collected from soil. The lysozyme gene was expressed solely in the nematode intestine and, as it is predicted to be secreted, may protect the nematode from microbial infections originating in the intestinal lumen or in the pseudocoelom. This paper demonstrates, to our knowledge for the first time, the immune response to infection in a plant parasitic nematode.

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

    Science.gov (United States)

    2010-03-10

    ... Animal and Plant Health Inspection Service Pale Cyst Nematode; Update of Quarantined Areas AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Notice of changes to quarantined area. SUMMARY: We are advising the public that we have made changes to the area in the State of Idaho that...

  5. 77 FR 22185 - Golden Nematode; Removal of Regulated Areas

    Science.gov (United States)

    2012-04-13

    ... Inspection Service 7 CFR Part 301 Golden Nematode; Removal of Regulated Areas AGENCY: Animal and Plant Health... townships of Elba and Byron in Genesee County, NY, from the list of generally infested areas. Surveys have... regulation of these areas was no longer necessary. As a result of that action, all the areas in...

  6. Grazing sericea lespedeza for control of gastrointestinal nematodes in lambs

    Science.gov (United States)

    Alternatives to chemical dewormers are needed to counter anthelmintic resistance and improve organic management systems. The objective was to examine the effectiveness of grazing sericea lespedeza (SL) compared with grass pastures for control of gastrointestinal nematodes (GIN) in lambs. In Experi...

  7. Dietary copper sulfate for control of gastrointestinal nematodes in goats

    Science.gov (United States)

    Prevalence of anthelmintic resistance in goats has necessitated studies for alternative means of gastrointestinal nematode (GIN) control. The objective was to determine the effectiveness of dietary copper sulfate for control of GIN in meat goats. Naturally infected buck kids received 0 (LC), 78 (M...

  8. Herbal dewormer fails to control gastrointestinal nematodes in goats

    Science.gov (United States)

    Gastrointestinal nematode (GIN) parasitism is the most important disease of small ruminants. Control is usually based on the use of chemical anthelmintics (dewormers); but these are prohibited from use in organic livestock, and the effectiveness of chemical anthelmintics in conventional operations ...

  9. Field study on nematode resistance in Nelore-breed cattle

    NARCIS (Netherlands)

    Bricarello, P A; Zaros, L G; Coutinho, L L; Rocha, R A; Kooyman, F N J; De Vries, E; Gonçalves, J R S; Lima, L G; Pires, A V; Amarante, A F T

    2007-01-01

    The present study evaluated Nelore cattle with different degrees of resistance to natural infections by gastrointestinal nematodes. One hundred weaned male cattle, 11-12 months of age, were kept on the same pasture and evaluated from October 2003 to February 2004. Faecal and blood samples were colle

  10. Garlic exhibits lack of control over gastrointestinal nematodes in goats

    Science.gov (United States)

    Gastrointestinal nematodes (GIN) continue to hinder small ruminant production because of anthelmintic resistance and lack of effective products for GIN control in organic production. The objective of this study was to examine the effectiveness of a commercially available certified organic garlic pr...

  11. IN VITRO CULTURING OF THE PREDATORY SOIL NEMATODE CLARKUS PAPILLATUS

    Science.gov (United States)

    Clarkus papillatus is a widely distributed predatory soil nematode and is of interest in the study of soil ecology, yet very little information exists on its in vitro culturing. In this investigation, an artificial environment was created to maintain C. papillatus for multi-gener...

  12. 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.

    2017-01-01

    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. PMID:28150734

  13. A serological approach to the identification of potato cyst nematodes.

    NARCIS (Netherlands)

    Schots, A.

    1988-01-01

    The potato cyst nematode species G.rostochiensis and G.pallida are a threat to the cultivation of potatoes. Their presence in the soil embodies a potential financial loss to the farmer either because of harvest reduction, or because of rejection of seed potatoes, and othe

  14. Managing Plant-Parasitic Nematodes in Established Red Raspberry Fields

    Science.gov (United States)

    The efficacy and phytotoxicity of post-plant treatments to control root lesion [Pratylenchus penetrans (Cobb), Chitwood & Otiefa] and dagger (Xiphinema bakeri Williams) nematodes in red raspberry (Rubus idaeus L.) were evaluated in four field studies conducted over three years. Spring spray applicat...

  15. 75 FR 54592 - Pale Cyst Nematode; Update of Quarantined Areas

    Science.gov (United States)

    2010-09-08

    ... INFORMATION: Background The pale cyst nematode (PCN, Globodera pallida) is a major pest of potato crops in... some weeds. The PCN is thought to have originated in Peru and is now widely distributed in many potato-growing regions of the world. PCN infestations may be expressed as patches of poor growth. Affected...

  16. IMMUNE REGULATING ES-PRODUCTS IN PARASITIC NEMATODES

    DEFF Research Database (Denmark)

    Bahlool, Qusay Zuhair Mohammad; Buchmann, Kurt; Kania, Per Walter;

    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...

  17. 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....

  18. 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...

  19. 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.

  20. Maintenance of genetic variation in automictic root-knot nematodes

    NARCIS (Netherlands)

    Van Der Beek, J. G. ( Hans); Punacker, Laas P.

    2008-01-01

    Differences in amplified fragment length polymorphisms (AFLP) between isolates and between mono-female lines of facultative automictic Meloidogyne hapla race A and obligate apomictic M incognita were determined to test the hypothesis that inverted meiosis occurs. DNA of the parthenogenetic nematode

  1. 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

  2. Radiation sensitivity of pine wood nematodes in woodchips

    Energy Technology Data Exchange (ETDEWEB)

    Eichholz, G.G.; Bogdanov, A.A. (Georgia Inst. of Tech., Atlanta, GA (USA)); Dwinell, L.D. (Forest Service, Athens, GA (USA). Forestry Sciences Lab.)

    1991-01-01

    The radiation sensitivity of pine wood nematodes has been tested over a range of dose values with a cesium-137 irradiator. Lethal doses were found to lie in a range above 6-8 kGy, too high to make this an economically attractive means of deinfestation for commercial woodchips. (author).

  3. 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 o

  4. 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.

  5. Detrended-Fluctuation Analysis of Nematode Movement in Heterogeneous Environment

    Science.gov (United States)

    Hapca, S. M.; Gonzalez-Nieto, P.; Tarquis, A. M.

    2009-04-01

    We consider multifractal analysis in time scale to analyse the effect of structural heterogeneity on the movement of the slug-parasitic nematode, Phasmarhabditis hermaphrodita. The study involves image recording and analysis of nematode movement on a homogeneous layer of technical agar compared to movement of nematodes in a structurally heterogeneous environment that was created by adding sand particles to the plates of agar. The temporal scaling properties of the recorded trails were studied using a detrended fluctuation based method to capture the complex dynamic of movement data by comparing the multiscaling characteristics of nematode step lengths as affected by the different environments. A systematic analysis of the exponent of the structure function and the generalized Hurst exponent revealed that, while in homogeneous environment the movement was characterized by a long-range correlation with a Hurst exponent H(q) close to 1, varying little with respect to the order q of the fluctuation function, the impact of sand particle was to reduce the degree of persistence in the movement, the step lenghts being characterized by a smaller Hurst exponent, yet more variable. The results suggest that the presence of structural heterogeneity introduces a new bias into the movement, which plays an important role in complex environments where the nematode movement may be obstructed by soil particles. References Tarquis, A.M., Morato, M. C., Castellanos M.T., Perdigones A. 2009. Comparison of Structure Function and Detrended Fluctuation Analysis of Wind Time Series, Riv. Nuevo Cimento, in press. Gao, J., Cao, Y., Tung, W.-W., Hu J., 2007. Multiscale Analysis of Complex Times Series. Eds. John Wiley & Sons.

  6. Mermithid nematodes found in adult Anopheles from southeastern Senegal

    Directory of Open Access Journals (Sweden)

    Kobylinski Kevin C

    2012-06-01

    Full Text Available Abstract Background Over two dozen mermithid nematodes have been described parasitizing mosquitoes worldwide, however, only two species were found in Africa. Mermithid nematodes kill their mosquito host upon emergence, which suggests that they could be developed as biological control agents of mosquitoes. Both Romanomermis culicivorax and Romanomermis iyengari have been reared for mass release to control numerous Anopheles species vector populations, and in one instance this may have led to reduced malaria prevalence in a human population. Methods Anopheles mosquitoes were collected during a malaria study in southeastern Senegal. Two different adult blood fed mosquitoes had a single mermithid nematode emerge from their anus while they were being held post-capture. Primers from the 18 S rDNA were developed to sequence nematode DNA and screen mosquitoes for mermithid DNA. 18 S rDNA from the Senegalese mermithid and other mermithid entries in GenBank were used to create a Maximum Parsimony tree of the Mermithidae family. Results The mermithid was present in 1.8% (10/551 of the sampled adult Anopheles species in our study area. The mermithid was found in An. gambiae s.s., An. funestus, and An. rufipes from the villages of Ndebou, Boundoucondi, and Damboucoye. Maximum parsimony analysis confirmed that the nematode parasites found in Anopheles were indeed mermithid parasites, and of the mermithid sequences available in GenBank, they are most closely related to Strelkovimermis spiculatus. Conclusions To our knowledge, this is the first report of mermithids from adult Anopheles mosquitoes in Senegal. The mermithid appears to infect Anopheles mosquitoes that develop in diverse larval habitats. Although maximum parsimony analysis determined the mermithid was closely related to Strelkovimermis spiculatus, several characteristics of the mermithid were more similar to the Empidomermis genus. Future mermithid isolations will hopefully allow: formal

  7. Nematode succession during composting and the potential of the nematode community as an indicator of compost maturity

    NARCIS (Netherlands)

    Steel, H.; Peña, de la E.; Fonderie, P.; Willekens, K.; Borgonie, G.; Bert, W.

    2010-01-01

    One of the key issues in compost research is to assess when the compost has reached a mature stage. The maturity status of the compost determines the quality of the final soil amendment product. The nematode community occurring in a Controlled Microbial Composting (CMC) process was analyzed with the

  8. Organic amendments and their influences on plant-parasitic and free-living nematodes: a promising method for nematode management?

    NARCIS (Netherlands)

    Thoden, T.C.; Korthals, G.W.; Termorshuizen, A.J.

    2011-01-01

    The use of organic soil amendments, such as green manures, animal manures, composts or slurries, certainly has many advantageous aspects for soil quality and is suggested as a promising tool for the management of plant-parasitic nematodes. However, during a recent literature survey we also found num

  9. Differential in vitro pathogenicity of predatory fungi of the genus Monacrosporium for phytonematodes, free-living nematodes and parasitic nematodes of cattle

    Directory of Open Access Journals (Sweden)

    A.P.S. Gomes

    1999-01-01

    Full Text Available In vitro tests were carried out on the pathogenicity of nine isolates of the predatory fungi of the genus Monacrosporium (5 M. sinense isolates, 3 M. appendiculatum and 1 M. thaumasium isolate for a phytonematode (second stage juveniles from Meloidogyne incognita, race 3, a free-living nematode (Panagrellus spp, and two gastrointestinal parasitic nematodes of cattle (infective larvae of Cooperia punctata and Haemonchus placei. A suspension containing 2,000 nematodes from each species was added to Petri dishes containing fungi and grown on 2% water-agar medium at 25oC in the dark for up to 7 days. The dishes were examined every other day for 7 days and predation-free nematodes were counted. The results showed that the free-living nematodes, Panagrellus spp, were the most susceptible (P³98.5% viable. However, a variable susceptibility of the nematodes to different fungi was observed. This indicates that the use of predatory fungi for the environmental control of nematodes will be limited by the multiplicity of nematodes in the environment and their differential susceptibility to fungal isolates of the same genus.

  10. 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.

  11. Integrated signaling networks in plant responses to sedentary endoparasitic nematodes: a perspective.

    Science.gov (United States)

    Li, Ruijuan; Rashotte, Aaron M; Singh, Narendra K; Weaver, David B; Lawrence, Kathy S; Locy, Robert D

    2015-01-01

    Sedentary plant endoparasitic nematodes can cause detrimental yield losses in crop plants making the study of detailed cellular, molecular, and whole plant responses to them a subject of importance. In response to invading nematodes and nematode-secreted effectors, plant susceptibility/resistance is mainly determined by the coordination of different signaling pathways including specific plant resistance genes or proteins, plant hormone synthesis and signaling pathways, as well as reactive oxygen signals that are generated in response to nematode attack. Crosstalk between various nematode resistance-related elements can be seen as an integrated signaling network regulated by transcription factors and small RNAs at the transcriptional, posttranscriptional, and/or translational levels. Ultimately, the outcome of this highly controlled signaling network determines the host plant susceptibility/resistance to nematodes.

  12. Reflections on plant and soil nematode ecology: past, present and future.

    Science.gov (United States)

    Ferris, Howard; Griffiths, Bryan S; Porazinska, Dorota L; Powers, Thomas O; Wang, Koon-Hui; Tenuta, Mario

    2012-06-01

    The purpose of this review is to highlight key developments in nematode ecology from its beginnings to where it stands today as a discipline within nematology. Emerging areas of research appear to be driven by crop production constraints, environmental health concerns, and advances in technology. In contrast to past ecological studies which mainly focused on management of plant-parasitic nematodes, current studies reflect differential sensitivity of nematode faunae. These differences, identified in both aquatic and terrestrial environments include response to stressors, environmental conditions, and management practices. Methodological advances will continue to influence the role nematodes have in addressing the nature of interactions between organisms, and of organisms with their environments. In particular, the C. elegans genetic model, nematode faunal analysis and nematode metagenetic analysis can be used by ecologists generally and not restricted to nematologists.

  13. A novel ascaroside controls the parasitic life cycle of the entomopathogenic nematode Heterorhabditis bacteriophora.

    Science.gov (United States)

    Noguez, Jaime H; Conner, Elizabeth S; Zhou, Yue; Ciche, Todd A; Ragains, Justin R; Butcher, Rebecca A

    2012-06-15

    Entomopathogenic nematodes survive in the soil as stress-resistant infective juveniles that seek out and infect insect hosts. Upon sensing internal host cues, the infective juveniles regurgitate bacterial pathogens from their gut that ultimately kill the host. Inside the host, the nematode develops into a reproductive adult and multiplies until unknown cues trigger the accumulation of infective juveniles. Here, we show that the entomopathogenic nematode Heterorhabditis bacteriophora uses a small-molecule pheromone to control infective juvenile development. The pheromone is structurally related to the dauer pheromone ascarosides that the free-living nematode Caenorhabditis elegans uses to control its development. However, none of the C. elegans ascarosides are effective in H. bacteriophora, suggesting that there is a high degree of species specificity. Our report is the first to show that ascarosides are important regulators of development in a parasitic nematode species. An understanding of chemical signaling in parasitic nematodes may enable the development of chemical tools to control these species.

  14. How do the macrocyclic lactones kill filarial nematode larvae?

    Science.gov (United States)

    Wolstenholme, Adrian J; Maclean, Mary J; Coates, Ruby; McCoy, Ciaran J; Reaves, Barbara J

    2016-09-01

    The macrocyclic lactones (MLs) are one of the few classes of drug used in the control of the human filarial infections, onchocerciasis and lymphatic filariasis, and the only one used to prevent heartworm disease in dogs and cats. Despite their importance in preventing filarial diseases, the way in which the MLs work against these parasites is unclear. In vitro measurements of nematode motility have revealed a large discrepancy between the maximum plasma concentrations achieved after drug administration and the amounts required to paralyze worms. Recent evidence has shed new light on the likely functions of the ML target, glutamate-gated chloride channels, in filarial nematodes and supports the hypothesis that the rapid clearance of microfilariae that follows treatment involves the host immune system.

  15. Effects of Abiotic Environmental Factors on Soybean Cyst Nematode

    Institute of Scientific and Technical Information of China (English)

    DUAN Yu-xi; ZHENG Ya-nan; CHEN Li-jie; ZHOU Xiao-min; WANG Yuan-yuan; SUN Jing-shuang

    2009-01-01

    As a pest, in order to complete its life history and reproduces effectively, soybean cyst nematode (SCN) (Heterodera glycines Ichinche 1952) must adapt to various environments and conditions for long periods of evolution. The nematode is widely dispersed year after year. Controlling this pest requires understanding characters and adaptability of SCN.Effects of abiotic factors, such as temperature, soil humidity, agrotype, pH value, ions, plant exudates, agricultural chemical and cultivation systems on SCN, are reviewed in this paper. The results show that SCN is able to endure various environmental stresses, especially low temperature. Because of its special life history, cyst stage help SCN over winter,resistance of SCN to environmental stress is strong. A few studies have reported the mechanism of SCN environmental adaptability. We emphasized the importance of studying environmental adaptability of SCN, which would benefit the control of SCN by ecological means.

  16. Discovery of filarial nematode DNA in Amblyomma americanum in Northern Virginia

    OpenAIRE

    Henning, Tyler C.; Orr, John M.; Smith, Joshua D.; Arias, Jorge R.; Rasgon, Jason L.; Norris, Douglas E.

    2015-01-01

    Ticks collected in 2011 were screened for the presence of filarial nematode genetic material, and positive samples were sequenced for analysis. Monanema-like filarial nematode DNA was recently discovered in Amblyomma americanum in northern Virginia, marking the first time genetic material from this parasite has been discovered in ticks in the state. Phylogenetic analysis revealed that this material was directly related to a previously discovered filarial nematode in A. americanum populations ...

  17. Transcriptome Analysis of Resistant and Susceptible Alfalfa Cultivars Infected With Root-Knot Nematode Meloidogyne incognita

    OpenAIRE

    Postnikova, Olga A.; Maria Hult; Jonathan Shao; Andrea Skantar; Nemchinov, Lev G.

    2015-01-01

    Nematodes are one of the major limiting factors in alfalfa production. Root-knot nematodes (RKN, Meloidogyne spp.) are widely distributed and economically important sedentary endoparasites of agricultural crops and they may inflict significant damage to alfalfa fields. As of today, no studies have been published on global gene expression profiling in alfalfa infected with RKN or any other plant parasitic nematode. Very little information is available about molecular mechanisms that contribute...

  18. Introduction to Nematode Genome and Transcriptome Announcements in the Journal of Nematology.

    Science.gov (United States)

    Denver, Dee R; Ragsdale, Erik J; Thomas, W Kelley; Zasada, Inga A

    2017-06-01

    The Journal of Nematology now offers publication of Nematode Genome Announcements (NGA) and Nematode Transcriptome Announcements (NTA). These brief reports announce the sequencing and assembly of a nematode genome or transcriptome resource, along with basic technical information on DNA sequencing and bioinformatic methods used. This publishing initiative offers a new avenue to openly and concisely communicate the availability and relevance of genome and transcriptome sequence resources to the broader scientific community.

  19. Integrated management of root-knot nematode, Meloidogyne incognita infestation in tomato and grapevine.

    Science.gov (United States)

    Kumari, N Swarna; Sivakumar, C V

    2005-01-01

    An integrated approach with the obligate bacterial parasite, Pasteuria penetrans and nematicides was assessed for the management of the root-knot nematode, Meloidogyne incognita infestation in tomato and grapevine. Seedlings of tomato cv. Co3 were transplanted into pots filled with sterilized soil and inoculated with nematodes (5000 juveniles/pot). The root powder of P. penetrans at 10 mg/pot was applied alone and in combination with carbofuran at 6 mg/pot. Application of P. penetrans along with carbofuran recorded lowest nematode infestation (107 nematodes/200 g soil) compared to control (325 nematodes/200 g soil). The rate of parasitization was 83.1% in the carbofuran and P. penetrans combination treatment as against 61.0% in the P. penetrans treatment only. The plant growth was also higher in the combination treatment compared to all other treatments. A field trial was carried out to assess the efficacy of P. penetrans and nematicides viz., carbofuran and phorate in the management of root-knot nematode, M. incognita infestation of grapevine cv. Muscat Hamburg. A nematode and P. penetrans infested grapevine field was selected and treatments either with carbofuran or phorate at 1 g a.i/vine was given. The observations were recorded at monthly interval. The results showed that the soil nematode population was reduced in nematicide treated plots. Suppression of nematodes was higher under phorate (117 nematodes/200 g soil) than under carbofuran (126.7 nematodes/200 g soil) treatment. The number of juveniles parasitized was also influenced by nematicides and spore load carried/juvenile with phorate being superior and the increase being 17.0 and 29.0% respectively over the control. The results of these experiment confirmed the compatibility of P. penetrans with nematicides and its biological control potential against the root-knot nematode.

  20. Freeliving marine nematodes as a pollution indicator of Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A hierarchical diversity index--taxonomic distinctnessindex +, which was first defined by Warwick and Clark in 1998, wasemployed to evaluate the pollution status of the Bohai Sea withfreeliving marine nematodes. The result showed that the Bohai Bayand other coastal sampling sites might be affected by oil and gasproduction and other anthropogenic influences. In other words,anthropogenic disturbance was affecting this component of thebenthos in these locations. And most offshore sampling sites in themiddle of the Bohai Sea were clear and unpolluted.

  1. Attraction of undulatory swimmers, such as nematodes, to surfaces

    Science.gov (United States)

    Yuan, Jinzhou; Raizen, David; Bau, Haim

    2014-11-01

    Nematodes play a significant role in the ecosystem; agriculture; human, animal, and plant disease; and medical research. The interactions between nematodes and surfaces may play an important role in nematodes' life cycle and ability to invade a host. We studied the effect of a surface on the dynamics of low-Reynolds number, undulating swimmers such as Caenorhabditis (C.) elegans -both wild type and touch-insensitive. The experiments demonstrated that swimmers located far from a surface selected randomly their direction of motion. In contrast, surface-proximate swimmers rotated towards, collided with, and swam along the surface for considerable time intervals, periodically contacting the surface with their anterior. Likewise, swimmers in a swarm were present at higher concentrations close to the surface. Both resistive force theory-based calculations and symmetry arguments predict that short range hydrodynamic torque, resulting from the interaction between the swimmer-induced flow field and the surface, rotate the swimmer towards the surface. We conclude that the surface attraction and following results from the interplay between short-range hydrodynamic and steric forces and is genotype-independent. The work was supported, in part, by NIH NIA 5R03AG042690-02 and NBIC NSF NSEC DMR08-32802.

  2. Prevalence and intensity of nematode parasites in Wisconsin ermine.

    Science.gov (United States)

    Dubay, Shelli; Buchholz, Matthew J; Lisiecki, Robert; Huspeni, Todd; Ginnett, Tim; Haen, Luke; Borsdorf, Phil

    2014-10-01

    In the midwestern United States, ermine ( Mustela erminea ) are economically important because they are legally harvested for pelts. Information on parasites of ermine is lacking, and the effects that nematode parasites have on body condition of ermine hosts are unknown. We identified Skrjabingylus nasicola and Filaroides martis in ermine trapped from 2007 to 2013 from 6 counties in Wisconsin. Small mammals, commonly consumed by ermine, serve as paratenic hosts for both parasites. Our goal was to identify how age and sex of ermine, along with year, influence nematode parasitism. We also investigated how infection affected body condition for male and female ermine using body mass standardized by length as an index of body condition. We commonly found S. nasicola and F. martis in male and female ermine, but both prevalence and intensity of infection were higher for males. Relative to juveniles (1 yr) male ermine did not exhibit significantly higher intensity or prevalence of either parasite. We found that body condition was not compromised by infection for either sex, and intensity of S. nasicola and prevalence of F. martis were highest during the 2010-2011 trapping season. Of the 6 yr studied, precipitation was highest during the summer before the 2010-2011 season, and increased precipitation can cause increases in populations of gastropod intermediate hosts. We think that several distinct natural history components, namely, mating structure, diet, and metabolic rate, influence nematode parasitism in ermine.

  3. Natural variation of outcrossing in the hermaphroditic nematode Pristionchus pacificus

    Directory of Open Access Journals (Sweden)

    Click Arielle

    2009-04-01

    Full Text Available Abstract Background Evolution of selfing can be associated with an increase in fixation of deleterious mutations, which in certain conditions can lead to species extinction. In nematodes, a few species evolved self-fertilization independently, making them excellent model systems to study the evolutionary consequences of this type of mating system. Results Here we determine various parameters that influence outcrossing in the hermaphroditic nematode Pristionchus pacificus and compare them to the better known Caenorhabditis elegans. These nematode species are distinct in terms of genetic diversity, which could be explained by differences in outcrossing rates. We find that, similarly to C. elegans, P. pacificus males are generated at low frequencies from self-fertilizing hermaphrodites and are relatively poor mating partners. Furthermore, crosses between different isolates reveal that hybrids have lower brood sizes than the pure strains, which is a sign of outbreeding depression. In contrast to C. elegans, P. pacificus has lower brood sizes and the male X-bearing sperm is able to outcompete the X-nullo sperm. Conclusion The results indicate that there is no evidence of any selection acting very strongly on P. pacificus males.

  4. A New Methodology for Evaluation of Nematode Viability

    Directory of Open Access Journals (Sweden)

    Sebastião Rodrigo Ferreira

    2015-01-01

    Full Text Available Nematodes infections are responsible for debilitating conditions and economic losses in domestic animals as well as livestock and are considered an important public health problem due to the high prevalence in humans. The nematode resistance for drugs has been reported for livestock, highlighting the importance for development of new anthelmintic compounds. The aim of the current study was to apply and compare fluorimetric techniques using Sytox and propidium iodide for evaluating the viability of C. elegans larvae after treatment with anthelmintic drugs. These fluorescent markers were efficient to stain larvae treated with ivermectin and albendazole sulfoxide. We observed that densitometric values were proportional to the concentration of dead larvae stained with both markers. Furthermore, data on motility test presented an inverse correlation with fluorimetric data when ivermectin was used. Our results showed that lower concentrations of drugs were effective to interfere in the processes of cellular transport while higher drugs concentrations were necessary in order to result in any damage to cell integrity. The methodology described in this work might be useful for studies that aim to evaluate the viability of nematodes, particularly for testing of new anthelminthic compounds using an easy, economic, reproducible, and no time-consuming technique.

  5. Origanum vulgare (Lamiaceae OVICIDAL POTENTIAL ON GASTROINTESTINAL NEMATODES OF CATTLE

    Directory of Open Access Journals (Sweden)

    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.

  6. Analysis of nematode mechanics by piezoresistive displacement clamp.

    Science.gov (United States)

    Park, Sung-Jin; Goodman, Miriam B; Pruitt, Beth L

    2007-10-30

    Studying animal mechanics is critical for understanding how signals in the neuromuscular system give rise to behavior and how force-sensing organs and sensory neurons work. Few techniques exist to provide forces and displacements appropriate for such studies. To address this technological gap, we developed a metrology using piezoresistive cantilevers as force-displacement sensors coupled to a feedback system to apply and maintain defined load profiles to micrometer-scale animals. We show that this system can deliver forces between 10(-8) and 10(-3) N across distances of up to 100 mum with a resolution of 12 nN between 0.1 Hz and 100 kHz. We use this new metrology to show that force-displacement curves of wild-type nematodes (Caenorhabditis elegans) are linear. Because nematodes have approximately cylindrical bodies, this finding demonstrates that nematode body mechanics can be modeled as a cylindrical shell under pressure. Little is known about the relative importance of hydrostatic pressure and shell mechanics, however. We show that dissipating pressure by cuticle puncture or decreasing it by hyperosmotic shock has only a modest effect on stiffness, whereas defects in the dpy-5 and lon-2 genes, which alter body shape and cuticle proteins, decrease and increase stiffness by 25% and 50%, respectively. This initial analysis of C. elegans body mechanics suggests that shell mechanics dominates stiffness and is a first step in understanding how body mechanics affect locomotion and force sensing.

  7. Sex-specific mating pheromones in the nematode Panagrellus redivivus.

    Science.gov (United States)

    Choe, Andrea; Chuman, Tatsuji; von Reuss, Stephan H; Dossey, Aaron T; Yim, Joshua J; Ajredini, Ramadan; Kolawa, Adam A; Kaplan, Fatma; Alborn, Hans T; Teal, Peter E A; Schroeder, Frank C; Sternberg, Paul W; Edison, Arthur S

    2012-12-18

    Nematodes use an extensive chemical language based on glycosides of the dideoxysugar ascarylose for developmental regulation (dauer formation), male sex attraction, aggregation, and dispersal. However, no examples of a female- or hermaphrodite-specific sex attractant have been identified to date. In this study, we investigated the pheromone system of the gonochoristic sour paste nematode Panagrellus redivivus, which produces sex-specific attractants of the opposite sex. Activity-guided fractionation of the P. redivivus exometabolome revealed that males are strongly attracted to ascr#1 (also known as daumone), an ascaroside previously identified from Caenorhabditis elegans hermaphrodites. Female P. redivivus are repelled by high concentrations of ascr#1 but are specifically attracted to a previously unknown ascaroside that we named dhas#18, a dihydroxy derivative of the known ascr#18 and an ascaroside that features extensive functionalization of the lipid-derived side chain. Targeted profiling of the P. redivivus exometabolome revealed several additional ascarosides that did not induce strong chemotaxis. We show that P. redivivus females, but not males, produce the male-attracting ascr#1, whereas males, but not females, produce the female-attracting dhas#18. These results show that ascaroside biosynthesis in P. redivivus is highly sex-specific. Furthermore, the extensive side chain functionalization in dhas#18, which is reminiscent of polyketide-derived natural products, indicates unanticipated biosynthetic capabilities in nematodes.

  8. Pathogenicity of Four Entomopathogenic Nematodes Species to G. mellonella Larvae

    Directory of Open Access Journals (Sweden)

    Pavel Hyrsl

    2011-06-01

    Full Text Available Entomopathogenic nematodes (EPNs of the genera Heterorhabditis and Steinernema are obligate and lethal insect parasites. In last decade they are widely used as biological control agents for pest insects of commercial crops, therefore research in this area is directly linked to agriculture. In this study, the pathogenicity of four nematode species (Heterorhabditis bacteriophora, Steinernema glaseri, Steinernema scarabaei and Steinernema feltiae was tested against Galleria mellonella larvae. Infective stage of EPNs together with their symbiotic bacteria kills insect host within 48 hours. The results show that mortality of insect host correlates with number of invaded infective juveniles (IJs. The invasion process is very fast, IJs enters insect host within a few hours. The importance of digestive tract as entering site was clearly demonstrated, larvae with empty gut are much more sensitive to nematode infection. Nemato-bacterial complex is very effective system overcoming insect immune defences. Encapsulation as the only one cellular reaction is activated, but in very low rate and was detected only during infection of H. bacteriophora.

  9. Soil nematode responses to increases in nitrogen deposition and precipitation in a temperate forest.

    Science.gov (United States)

    Sun, Xiaoming; Zhang, Xiaoke; Zhang, Shixiu; Dai, Guanhua; Han, Shijie; Liang, Wenju

    2013-01-01

    The environmental changes arising from nitrogen (N) deposition and precipitation influence soil ecological processes in forest ecosystems. However, the corresponding effects of environmental changes on soil biota are poorly known. Soil nematodes are the important bioindicator of soil environmental change, and their responses play a key role in the feedbacks of terrestrial ecosystems to climate change. Therefore, to explore the responsive mechanisms of soil biota to N deposition and precipitation, soil nematode communities were studied after 3 years of environmental changes by water and/or N addition in a temperate forest of Changbai Mountain, Northeast China. The results showed that water combined with N addition treatment decreased the total nematode abundance in the organic horizon (O), while the opposite trend was found in the mineral horizon (A). Significant reductions in the abundances of fungivores, plant-parasites and omnivores-predators were also found in the water combined with N addition treatment. The significant effect of water interacted with N on the total nematode abundance and trophic groups indicated that the impacts of N on soil nematode communities were mediated by water availability. The synergistic effect of precipitation and N deposition on soil nematode communities was stronger than each effect alone. Structural equation modeling suggested water and N additions had direct effects on soil nematode communities. The feedback of soil nematodes to water and nitrogen addition was highly sensitive and our results indicate that minimal variations in soil properties such as those caused by climate changes can lead to severe changes in soil nematode communities.

  10. Nematode abundance at the oxygen minimum zone in the Arabian Sea

    Science.gov (United States)

    Cook, Adam A.; Lambshead, P. John D.; Hawkins, Lawrence E.; Mitchell, Nicola; Levin, Lisa A.

    2000-01-01

    This paper supports the hypothesis that low oxygen does not influence deep-sea nematode abundance by investigating an oxygen minimum zone (OMZ) on the Oman slope in the Arabian Sea. Correlation with a number of environmental variables indicated that food quality (measured as the hydrogen index) rather than oxygen was the major predictor of nematode abundance. Nematode abundance was also positively correlated with abundance of total macrofauna, annelids, spionid polychaetes and macrofaunal tube builders. Comparison with published data showed Arabian Sea nematode abundance to be similar to that of the Porcupine Seabight and Bay of Biscay regions of the northeast Atlantic, which also receive significant quantities of phytodetritus but have no OMZ.

  11. 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...

  12. Filarial Nematode Infection in Ixodes scapularis Ticks Collected from Southern Connecticut

    Directory of Open Access Journals (Sweden)

    Pabbati Namrata

    2014-05-01

    Full Text Available It was recently demonstrated that the lone star tick Amblyomma americanum could harbor filarial nematodes within the genus Acanthocheilonema. In this study, Ixodes scapularis (deer ticks collected from Southern Connecticut were evaluated for their potential to harbor filarial nematodes. Non-engorged nymphal and adult stage Ixodes scapularis ticks were collected in Southern Connecticut using the standard drag method. In situ hybridization with filarial nematode specific sequences demonstrated the presence of filarial nematodes in Ixodes ticks. Filarial nematode specific DNA sequences were amplified and confirmed by direct sequencing in Ixodes nymphal and adult ticks using either general filarial nematode or Onchocercidae family specific PCR primers. Phylogenetic analysis of the 12S rDNA gene sequence indicated that the filarial nematode infecting Ixodes scapularis ticks is most closely related to the species found in Amblyoma americanum ticks and belongs to the genus of Acanthocheilonema. Our data also demonstrated that infection rate of these filarial nematode in Ixodes ticks is relatively high (about 22% and 30% in nymphal and adult Ixodes ticks, respectively. In summary, the results from our studies demonstrated that filarial nematode infection was found in Ixodes ticks similar to what has been found in Amblyomma americanum ticks.

  13. Discovery of filarial nematode DNA in Amblyomma americanum in Northern Virginia.

    Science.gov (United States)

    Henning, Tyler C; Orr, John M; Smith, Joshua D; Arias, Jorge R; Rasgon, Jason L; Norris, Douglas E

    2016-03-01

    Ticks collected in 2011 were screened for the presence of filarial nematode genetic material, and positive samples were sequenced for analysis. Monanema-like filarial nematode DNA was recently discovered in Amblyomma americanum in northern Virginia, marking the first time genetic material from this parasite has been discovered in ticks in the state. Phylogenetic analysis revealed that this material was directly related to a previously discovered filarial nematode in A. americanum populations in Maryland as well as recently identified parasites in Ixodes scapularis from southern Connecticut. Further study is warranted to visually confirm the presence of these nematodes, characterize their distribution, and determine if these ticks are intermediate hosts.

  14. The Effect of Crop Rotation on Soil Nematode Community Composition in a Greenhouse

    Institute of Scientific and Technical Information of China (English)

    Jingwen LU; Wei SHENG; Qian YU; Zijing CHEN; Qiang XU; Qian WANG; Linlin DONG

    2015-01-01

    Objective] The aim was to identify changes in a nematode community in response to crop rotation and to determine the appropriate catch crop for a green-house. [Method] The experiment was carried out in a typical 6-year-old greenhouse, in which cucumber crops were cultivated twice each year (in spring and autumn), and catch crops were planted in summer. The total number of nematodes was counted and nematode community indices were calculated after col ecting soil sam-ples in different stages. [Result] Total nematode abundance was decreased in the soils of catch crop in contrast with former crops (cucumber crops). The abundance of the nematode community was reduced in the treatment of crop rotation compared to the soils of catch crop. ln addition, the number of nematode taxa was significant-ly reduced by the treatment of crown daisy compared to the treatments of fol owing crops. Crop rotation regulated the functional composition of the nematode community by increasing the omnivores-predators functional group and decreasing the relative abundance of root herbivores. [Conclusion] These results indicate that crop rotation affects the nematode community in abundance, diversity and functional composition of the nematode community and crown daisy can be served as the most appropri-ate catch crop in the greenhouse.

  15. Control of Root-knot Nematodes on Tomato in Stone Wool Substrate with Biological Nematicides

    Science.gov (United States)

    López-Pérez, Jose Antonio; Edwards, Scott

    2011-01-01

    The efficacy of four biological nematicides on root-galling, root-knot nematode (Meloidogyne incognita) reproduction, and shoot weight of tomato (Solanum lycopersicum) grown in stone wool substrate or in pots with sandy soil was compared to an oxamyl treatment and a non-treated control. In stone wool grown tomato, Avid® (a.i. abamectin) was highly effective when applied as a drench at time of nematode inoculation. It strongly reduced root-galling and nematode reproduction, and prevented a reduction in tomato shoot weight. However, applying the product one week before, or two weeks after nematode inoculation was largely ineffective. This shows that Avid® has short-lived, non-systemic activity. The effects of Avid® on nematode symptoms and reproduction on soil-grown tomato were only very minor, probably due to the known strong adsorption of the active ingredient abamectin to soil particles. The neem derived product Ornazin® strongly reduced tomato root-galling and nematode reproduction only in stone wool and only when applied as a drench one week prior to nematode inoculation, suggesting a local systemic activity or modification of the root system, rendering them less suitable host for the nematodes. This application however also had some phytotoxic effect, reducing tomato shoot weights. The other two products, Nema-Q™ and DiTera®, did not result in strong or consistent effects on nematode symptoms or reproduction. PMID:22791920

  16. Free-living nematodes in the freshwater food web: a review.

    Science.gov (United States)

    Majdi, Nabil; Traunspurger, Walter

    2015-03-01

    Free-living nematodes are well-recognized as an abundant and ubiquitous component of benthic communities in inland waters. Compelling evidence from soil and marine ecosystems has highlighted the importance of nematodes as trophic intermediaries between microbial production and higher trophic levels. However, the paucity of empirical evidence of their role in freshwater ecosystems has hampered their inclusion in our understanding of freshwater food web functioning. This literature survey provides an overview of research efforts in the field of freshwater nematode ecology and of the complex trophic interactions between free-living nematodes and microbes, other meiofauna, macro-invertebrates, and fishes. Based on an analysis of the relevant literature and an appreciation of the potential of emerging approaches for the evaluation of nematode trophic ecology, we point out research gaps and recommend relevant directions for further research. The latter include (i) interactions of nematodes with protozoans and fungi; (ii) nonconsumptive effects of nematodes on microbial activity and the effects of nematodes on associated key ecosystem processes (decomposition, primary production); and (iii) the feeding selectivity and intraspecific feeding variability of nematodes and their potential impacts on the structure of benthic communities.

  17. Control of root-knot nematodes on tomato in stone wool substrate with biological nematicides.

    Science.gov (United States)

    López-Pérez, Jose Antonio; Edwards, Scott; Ploeg, Antoon

    2011-06-01

    The efficacy of four biological nematicides on root-galling, root-knot nematode (Meloidogyne incognita) reproduction, and shoot weight of tomato (Solanum lycopersicum) grown in stone wool substrate or in pots with sandy soil was compared to an oxamyl treatment and a non-treated control. In stone wool grown tomato, Avid® (a.i. abamectin) was highly effective when applied as a drench at time of nematode inoculation. It strongly reduced root-galling and nematode reproduction, and prevented a reduction in tomato shoot weight. However, applying the product one week before, or two weeks after nematode inoculation was largely ineffective. This shows that Avid® has short-lived, non-systemic activity. The effects of Avid® on nematode symptoms and reproduction on soil-grown tomato were only very minor, probably due to the known strong adsorption of the active ingredient abamectin to soil particles. The neem derived product Ornazin® strongly reduced tomato root-galling and nematode reproduction only in stone wool and only when applied as a drench one week prior to nematode inoculation, suggesting a local systemic activity or modification of the root system, rendering them less suitable host for the nematodes. This application however also had some phytotoxic effect, reducing tomato shoot weights. The other two products, Nema-Q™ and DiTera®, did not result in strong or consistent effects on nematode symptoms or reproduction.

  18. Pest Risk Assessment for Bursaphelenchus xylophilus Introduced to Yunnan Based on ArcView GIS%基于ArcView GIS的松材线虫传入云南风险评估

    Institute of Scientific and Technical Information of China (English)

    王峰; 王志英; 喻盛甫

    2007-01-01

    根据国际粮农组织(Food and Agriculture Organization of the United Nations,FAO)的国际植物检疫措施标准-检疫性有害生物风险分析(Pest Risk Analysis for Quarantine Pests Including Analysis of Environmental Risks and Living Modified Organisms)以及欧洲和地中海地区植物保护组织(European and Mediterranean Plant Protection Organisation,EPPO)的有害生物风险评估方案,应用美国环境系统研究所(ESRI)开发的地理信息系统(Geographic Information System, GIS)软件ArcView 3.2对云南省129个县(市、区)的年平均气温、年平均降雨、日照、寄主分布和媒介昆虫等信息进行分析,对松材线虫(Bursaphelenchus xylophilus)进入可能性、定殖可能性和经济影响等方面进行了风险评估(Pest Risk Assessment,PRA).划定松材线虫病发生低风险区2县、松材线虫病发生中度风险区20县(市、区)、松材线虫病发生较高风险区49县(市、区),其余县58县(市、区)为松材线虫病发生高度风险区.划定云南省北纬26°以南地区为重点防护区.并绘制寄主分布图、年平均气温图、松墨天牛分布图等风险评估地图.

  19. 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 < 0.001). G-proteins and mitogen activated protein kinases are considered crucial for signal transduction mechanism. Results of qRT-PCR of 20 genes further validated the sequencing data. Further, variations in gene expression among Duddingtonia flagrans and A. conoides showed septicity of 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.

  20. 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.

  1. An automated system for measuring parameters of nematode sinusoidal movement

    Directory of Open Access Journals (Sweden)

    Stirbl Robert C

    2005-02-01

    Full Text Available Abstract Background Nematode sinusoidal movement has been used as a phenotype in many studies of C. elegans development, behavior and physiology. A thorough understanding of the ways in which genes control these aspects of biology depends, in part, on the accuracy of phenotypic analysis. While worms that move poorly are relatively easy to describe, description of hyperactive movement and movement modulation presents more of a challenge. An enhanced capability to analyze all the complexities of nematode movement will thus help our understanding of how genes control behavior. Results We have developed a user-friendly system to analyze nematode movement in an automated and quantitative manner. In this system nematodes are automatically recognized and a computer-controlled microscope stage ensures that the nematode is kept within the camera field of view while video images from the camera are stored on videotape. In a second step, the images from the videotapes are processed to recognize the worm and to extract its changing position and posture over time. From this information, a variety of movement parameters are calculated. These parameters include the velocity of the worm's centroid, the velocity of the worm along its track, the extent and frequency of body bending, the amplitude and wavelength of the sinusoidal movement, and the propagation of the contraction wave along the body. The length of the worm is also determined and used to normalize the amplitude and wavelength measurements. To demonstrate the utility of this system, we report here a comparison of movement parameters for a small set of mutants affecting the Go/Gq mediated signaling network that controls acetylcholine release at the neuromuscular junction. The system allows comparison of distinct genotypes that affect movement similarly (activation of Gq-alpha versus loss of Go-alpha function, as well as of different mutant alleles at a single locus (null and dominant negative alleles

  2. 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

  3. 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

  4. 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

  5. Carbofuran effects in soil nematode communities: using trait and taxonomic based approaches.

    Science.gov (United States)

    Chelinho, Sónia; Dieter Sautter, Klaus; Cachada, Anabela; Abrantes, Isabel; Brown, George; Costa Duarte, Armando; Sousa, José Paulo

    2011-10-01

    This work intends to implement the use of native soil nematode communities in ecotoxicological tests using a model pesticide and two geographically nematode communities (Mediterranean and sub-tropical) in order to obtain new perspectives on the evaluation of the toxic potential of chemical substances. The environmental condition of the nematode communities was described using a trait-based approach (grouping the organisms according to their feeding traits) and a traditional taxonomic method (identification to family level). Effects on total nematode abundance, number of families and abundance of nematode feeding groups as well as potential shifts in both trophic and family structure were assessed. Agricultural soils from Curitiba (Brazil) and Coimbra (Portugal) were sampled and the corresponding nematode communities were extracted. Part of the collected soil was defaunated and spiked with four doses of a carbofuran commercial formulation. Afterwards each of the replicates was inoculated with a nematode suspension containing ≈200 or 300 nematodes. After 14 and 28 d of exposure the nematodes were extracted, counted and identified at family level and separately classified according to their feeding traits. The patterns of nematode responses revealed a decrease in the total abundance and a reduction in the number of families. Despite the similar effects observed for both communities, statistically significant toxic effects were only found within the Portuguese community. The total nematode abundance was significantly reduced at the highest carbofuran concentrations and significant shifts in the family structure were detected. However, the trophic structure, i.e., the contribution of each feeding group for the overall community structure, did not significantly change along the contamination gradient. Results showed that using such a trait-based approach may increase the ecological relevance of toxicity data, by establishing communalities in the response to a chemical

  6. Insights into Adaptations to a Near-Obligate Nematode Endoparasitic Lifestyle from the Finished Genome of Drechmeria coniospora

    NARCIS (Netherlands)

    Zhang, L.; Zhou, Z.; Guo, Q.; Fokkens, L.; Miskei, M.; Pócsi, I.; Zhang, W.; Chen, M.; Wang, L.; Sun, Y.; Donzelli, B.G.G.; Gibson, D.M.; Nelson, D.R.; Luo, J.G.; Rep, M.; Liu, H.; Yang, S.; Wang, J.; Krasnoff, S.B.; Xu, Y.; Molnár, I.; Lin, M.

    2016-01-01

    Nematophagous fungi employ three distinct predatory strategies: nematode trapping, parasitism of females and eggs, and endoparasitism. While endoparasites play key roles in controlling nematode populations in nature, their application for integrated pest management is hindered by the limited

  7. Brassicacea-based management strategies as an alternative to combat nematode pests

    NARCIS (Netherlands)

    Fourie, Hendrika; Ahuja, Preeti; Lammers, Judith; Daneel, Mieke

    2016-01-01

    Nematode pests parasitise and cause substantial crop yield and quality losses to a wide range of crops worldwide. To minimize such damage, the exploitation and development of alternative nematode control strategies are becoming increasingly important, particularly as a result of global efforts to

  8. RNAseq Analysis of the Drosophila Response to the Entomopathogenic Nematode Steinernema

    Directory of Open Access Journals (Sweden)

    Shruti Yadav

    2017-06-01

    Full Text Available Drosophila melanogaster is an outstanding model to study the molecular and functional basis of host–pathogen interactions. Currently, our knowledge of microbial infections in D. melanogaster is well understood; however, the response of flies to nematode infections is still in its infancy. Here, we have used the potent parasitic nematode Steinernema carpocapsae, which lives in mutualism with its endosymbiotic bacteria Xenorhabdus nematophila, to examine the transcriptomic basis of the interaction between D. melanogaster and entomopathogenic nematodes. We have employed next-generation RNA sequencing (RNAseq to investigate the transcriptomic profile of D. melanogaster larvae in response to infection by S. carpocapsae symbiotic (carrying X. nematophila or axenic (lacking X. nematophila nematodes. Bioinformatic analyses have identified the strong induction of genes that are associated with the peritrophic membrane and the stress response, as well as several genes that participate in developmental processes. We have also found that genes with different biological functions are enriched in D. melanogaster larvae responding to either symbiotic or axenic nematodes. We further show that while symbiotic nematode infection enriched certain known immune-related genes, axenic nematode infection enriched several genes associated with chitin binding, lipid metabolic functions, and neuroactive ligand receptors. In addition, we have identified genes with a potential role in nematode recognition and genes with potential antinematode activity. Findings from this study will undoubtedly set the stage for the identification of key regulators of antinematode immune mechanisms in D. melanogaster, as well as in other insects of socioeconomic importance.

  9. RNAseq Analysis of the Drosophila Response to the Entomopathogenic Nematode Steinernema.

    Science.gov (United States)

    Yadav, Shruti; Daugherty, Sean; Shetty, Amol Carl; Eleftherianos, Ioannis

    2017-06-07

    Drosophila melanogaster is an outstanding model to study the molecular and functional basis of host-pathogen interactions. Currently, our knowledge of microbial infections in D. melanogaster is well understood; however, the response of flies to nematode infections is still in its infancy. Here, we have used the potent parasitic nematode Steinernema carpocapsae, which lives in mutualism with its endosymbiotic bacteria Xenorhabdus nematophila, to examine the transcriptomic basis of the interaction between D. melanogaster and entomopathogenic nematodes. We have employed next-generation RNA sequencing (RNAseq) to investigate the transcriptomic profile of D. melanogaster larvae in response to infection by S. carpocapsae symbiotic (carrying X. nematophila) or axenic (lacking X. nematophila) nematodes. Bioinformatic analyses have identified the strong induction of genes that are associated with the peritrophic membrane and the stress response, as well as several genes that participate in developmental processes. We have also found that genes with different biological functions are enriched in D. melanogaster larvae responding to either symbiotic or axenic nematodes. We further show that while symbiotic nematode infection enriched certain known immune-related genes, axenic nematode infection enriched several genes associated with chitin binding, lipid metabolic functions, and neuroactive ligand receptors. In addition, we have identified genes with a potential role in nematode recognition and genes with potential antinematode activity. Findings from this study will undoubtedly set the stage for the identification of key regulators of antinematode immune mechanisms in D. melanogaster, as well as in other insects of socioeconomic importance. Copyright © 2017 Yadav et al.

  10. RNAseq Analysis of the Drosophila Response to the Entomopathogenic Nematode Steinernema

    Science.gov (United States)

    Yadav, Shruti; Daugherty, Sean; Shetty, Amol Carl; Eleftherianos, Ioannis

    2017-01-01

    Drosophila melanogaster is an outstanding model to study the molecular and functional basis of host–pathogen interactions. Currently, our knowledge of microbial infections in D. melanogaster is well understood; however, the response of flies to nematode infections is still in its infancy. Here, we have used the potent parasitic nematode Steinernema carpocapsae, which lives in mutualism with its endosymbiotic bacteria Xenorhabdus nematophila, to examine the transcriptomic basis of the interaction between D. melanogaster and entomopathogenic nematodes. We have employed next-generation RNA sequencing (RNAseq) to investigate the transcriptomic profile of D. melanogaster larvae in response to infection by S. carpocapsae symbiotic (carrying X. nematophila) or axenic (lacking X. nematophila) nematodes. Bioinformatic analyses have identified the strong induction of genes that are associated with the peritrophic membrane and the stress response, as well as several genes that participate in developmental processes. We have also found that genes with different biological functions are enriched in D. melanogaster larvae responding to either symbiotic or axenic nematodes. We further show that while symbiotic nematode infection enriched certain known immune-related genes, axenic nematode infection enriched several genes associated with chitin binding, lipid metabolic functions, and neuroactive ligand receptors. In addition, we have identified genes with a potential role in nematode recognition and genes with potential antinematode activity. Findings from this study will undoubtedly set the stage for the identification of key regulators of antinematode immune mechanisms in D. melanogaster, as well as in other insects of socioeconomic importance. PMID:28450373

  11. In vivo efficacy of chicory silage against parasitic nematodes in cattle

    DEFF Research Database (Denmark)

    Pena-Espinoza, Miguel Angel; Desrues, Oliver; Williams, A.;

    Infections with parasitic nematodes are a persistent risk for grazing cattle, which is met with widespread use of synthetic anthelmintics. However, heavy reliance on these drugs may lead to selection of drug-resistant nematodes. Integrated control strategies, including anti-parasitic crops, are n...

  12. 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 o

  13. 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.

  14. Heterodera schachtii nematodes interfere with aphid-plant relations on Brassica oleracea.

    Science.gov (United States)

    Hol, W H Gera; De Boer, Wietse; Termorshuizen, Aad J; Meyer, Katrin M; Schneider, Johannes H M; Van Der Putten, Wim H; Van Dam, Nicole M

    2013-09-01

    Aboveground and belowground herbivore species modify plant defense responses differently. Simultaneous attack can lead to non-additive effects on primary and secondary metabolite composition in roots and shoots. We previously found that aphid (Brevicoryne brassicae) population growth on Brassica oleracea was reduced on plants that were infested with nematodes (Heterodera schachtii) prior (4 weeks) to aphid infestation. Here, we examined how infection with root-feeding nematodes affected primary and secondary metabolites in the host plant and whether this could explain the increase in aphid doubling time from 3.8 to 6.7 days. We hypothesized that the effects of herbivores on plant metabolites would depend on the presence of the other herbivore and that nematode-induced changes in primary metabolites would correlate with reduced aphid performance. Total glucosinolate concentration in the leaves was not affected by nematode presence, but the composition of glucosinolates shifted, as gluconapin concentrations were reduced, while gluconapoleiferin concentrations increased in plants exposed to nematodes. Aphid presence increased 4-methoxyglucobrassicin concentrations in leaves, which correlated positively with the number of aphids per plant. Nematodes decreased amino acid and sugar concentrations in the phloem. Aphid population doubling time correlated negatively with amino acids and glucosinolate levels in leaves, whereas these correlations were non-significant when nematodes were present. In conclusion, the effects of an herbivore on plant metabolites were independent of the presence of another herbivore. Nematode presence reduced aphid population growth and disturbed feeding relations between plants and aphids.

  15. 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

  16. 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, co

  17. First report of plant-parasitic nematode Meloidoderita salina in the Netherlands

    NARCIS (Netherlands)

    Ashrafi, S.; Helder, J.; Elsen, van den S.J.J.; Jansen, M.; Karssen, G.

    2014-01-01

    After the description of the root-parasitic nematode Meloidoderita salina from a tidal salt marsh in France (1), an additional sampling was carried out to search for the presence of this unusual nematode in a tidal salt marsh area close to Sint-Annaland, province Zeeland in the Netherlands. In Augus

  18. The Activation and Suppression of Plant Innate Immunity by Parasitic Nematodes

    NARCIS (Netherlands)

    Goverse, A.; Smant, G.

    2014-01-01

    Plant-parasitic nematodes engage in prolonged and intimate relationships with their host plants, often involving complex alterations in host cell morphology and function. It is puzzling how nematodes can achieve this, seemingly without activating the innate immune system of their hosts. Secretions r

  19. Transcript Analysis of Parasitic Females of the Sedentary Semi-Endoparasitic Nematode Rotylenchulus reniformis

    Science.gov (United States)

    The reniform nematode, Rotylenchulus reniformis Linford & Oliveira, is a sedentary semi-endoparasitic roundworm that infects the roots of many economically important plant species. Engineered resistance to plant-parasitic nematodes (PPNs) via RNA-interference (RNAi) has shown promise in providing h...

  20. Canine Infections with Onchocerca lupi Nematodes, United States, 2011–2014

    Science.gov (United States)

    Giannelli, Alessio; Latrofa, Maria S.; Dantas-Torres, Filipe; Trumble, Nicole Scotty; Chavkin, Matt; Kennard, Gavin; Eberhard, Mark L.; Bowman, Dwight D.

    2015-01-01

    Infections with Onchocerca lupi nematodes are diagnosed sporadically in the United States. We report 8 cases of canine onchocercosis in Minnesota, New Mexico, Colorado, and Florida. Identification of 1 cytochrome c oxidase subunit 1 gene haplotype identical to 1 of 5 from Europe suggests recent introduction of this nematode into the United States. PMID:25897859

  1. RNA Interference: A Novel Source of Resistance to Combat Plant Parasitic Nematodes.

    Science.gov (United States)

    Banerjee, Sagar; Banerjee, Anamika; Gill, Sarvajeet S; Gupta, Om P; Dahuja, Anil; Jain, Pradeep K; Sirohi, Anil

    2017-01-01

    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.

  2. Immunofluorescent Localization of Tobacco Ringspot Nepovirus in the Vector Nematode Xiphinema americanum.

    Science.gov (United States)

    Wang, S; Gererich, R C

    1998-09-01

    ABSTRACT An indirect immunofluorescent technique was developed to localize tobacco ringspot nepovirus (TRSV) in the vector nematode Xiphinema americanum sensu stricto. A population of this nematode that efficiently transmitted TRSV was given an acquisition access period of 10 days on TRSV-infected cucumber. Treatment of fragments of viruliferous nematodes with a polyclonal antiserum against TRSV followed by fluorescein isothiocyanate-conjugated goat anti-rabbit immunoglobulin G resulted in virus-specific bright fluorescence only in the lumen of the stylet extension and esophagus. Virus-specific fluorescent signals were observed in the virus-retention region of 44% of the nematode fragments examined. The percentage of nematodes labeled with virus-specific fluorescence increased as the acquisition access period increased from 0 to 22 days; the increase paralleled the increase in the transmission efficiency of the nematode population. Visualization of the entire virus-retention region of individual nematodes within a population of vector or nonvector nematodes provides a rapid and simple means of monitoring specific attachment of plant viruses.

  3. A novel approach to biocontrol: release of live insect hosts pre-infected with entomopathogenic nematodes

    Science.gov (United States)

    As a new application approach, we tested the efficacy of releasing live insect hosts that were pre-infected with entomopathogenic nematodes against insect pests living in cryptic habitats. We hypothesized that the pre-infected hosts could carry the next generation of emerging nematode infective juv...

  4. Preferred use of bacteria over phytoplankton by deep-sea nematodes in polar regions

    NARCIS (Netherlands)

    Ingels, J.; Driessche, Van den P.; Mesel, de I.G.; Vanhove, S.; Moens, T.; Vanreusel, A.

    2010-01-01

    The present study explored the selective feeding properties of Antarctic and Arctic deep-sea nematodes within an experimental setup. Nematodes are assumed to play an important role in the carbon flux within the polar bathyal food webs, but knowledge about their natural diets is limited. For the firs

  5. Sunn Hemp cover cropping and organic fertilizer effects on the nematode community under temperate growing conditions

    Science.gov (United States)

    Plantings of sunn hemp as a cover crop have been experimentally shown to improve soil health, reduce plant-parasitic nematodes, and increase nematode-antagonistic microorganisms. However, these studies have been largely conducted in tropical and subtropical regions. To investigate the impacts of sun...

  6. Entomopathogenic Nematodes (Steinernematidae and Heterorhabditidae) for Biological Control of Soil Pests

    OpenAIRE

    HAZIR, Selçuk; Kaya, Harry K.; Stock, S. Patricia; KESKİN, Nevin

    2014-01-01

    Several species of entomopathogenic nematodes in the families Steinernematidae (Steinernema) and Heterorhabditidae (Heterorhabditis) are being produced commercially and used as biological control agents against many soil insect pests and insects in cryptic habitats in many parts of the world. These nematodes, which are mutualistically associated with bacteria (Steinernema with Xenorhabdus bacteria and Heterorhabditis with Photorhabdus bacteria), offer a number of advantages because they have ...

  7. Biotechnological application of functional genomics towards plant-parasitic nematode control.

    Science.gov (United States)

    Li, Jiarui; Todd, Timothy C; Lee, Junghoon; Trick, Harold N

    2011-12-01

    Plant-parasitic nematodes are primary biotic factors limiting the crop production. Current nematode control strategies include nematicides, crop rotation and resistant cultivars, but each has serious limitations. RNA interference (RNAi) represents a major breakthrough in the application of functional genomics for plant-parasitic nematode control. RNAi-induced suppression of numerous genes essential for nematode development, reproduction or parasitism has been demonstrated, highlighting the considerable potential for using this strategy to control damaging pest populations. In an effort to find more suitable and effective gene targets for silencing, researchers are employing functional genomics methodologies, including genome sequencing and transcriptome profiling. Microarrays have been used for studying the interactions between nematodes and plant roots and to measure both plants and nematodes transcripts. Furthermore, laser capture microdissection has been applied for the precise dissection of nematode feeding sites (syncytia) to allow the study of gene expression specifically in syncytia. In the near future, small RNA sequencing techniques will provide more direct information for elucidating small RNA regulatory mechanisms in plants and specific gene silencing using artificial microRNAs should further improve the potential of targeted gene silencing as a strategy for nematode management. © 2011 The Authors. Plant Biotechnology Journal © 2011 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

  8. Multiple species-specific controls of root-feeding nematodes in natural soils

    NARCIS (Netherlands)

    Piśkiewicz, A.M.; Duyts, H.; Van der Putten, W.H.

    2008-01-01

    One of the major limitations to enhance sustainability of crop production systems is the inability to control root-feeding nematodes without using chemical biocides. In soils under wild vegetation, however, root-feeding nematodes affect plant performance and plant community composition varying from

  9. A review of introductions of pathogens and nematodes for classical biological control of insects and mites

    Science.gov (United States)

    Ann E. Hajek; Michael L. McManus; Italo Delalibera Junior

    2007-01-01

    Compared with parasitoids and predators, classical biological control programs targeting arthropod pests have used pathogens and nematodes very little. However, some pathogens and nematodes that have been introduced have become established and provided excellent control and have been introduced in increasing numbers of areas over decades, often after distributions of...

  10. Community composition, diversity and metabolic footprints of soil nematodes in differently-aged temperate forests

    NARCIS (Netherlands)

    Zhang, Xiaoke; Guan, Pingting; Wang, Yaolei; Li, Qi; Zhang, Shixiu; Zhang, Zhiyong; Bezemer, T. Martijn; Liang, Wenju

    2015-01-01

    Abstract Soil nematode communities can provide important information about soil food web structure and function. However, how soil nematode communities and their metabolic footprints change over time in temperate forests is not well known. We examined the changes in the composition, diversity and me

  11. Product evaluation for reniform nematode suppression in Mississippi Delta sweetpotato production, 2011

    Science.gov (United States)

    The reniform nematode, Rotylenchulus reniformis, can cause significant losses in sweetpotato, Ipomoea batatas, production in the Mississippi Delta. Reniform nematode is a microscopic plant parasite that feeds on sweetpotato roots causing severe stunting of root growth. Reduction in yield due to the ...

  12. On the relationships between nematodes, mycorrhizal fungi and plants: functional composition of species and plant performance

    NARCIS (Netherlands)

    Brussaard, L.; Kuyper, T.W.; Goede, de R.G.M.

    2001-01-01

    We analysed data from descriptive and experimental studies on the possible relationships between plants, nematodes and mycorrhizal fungi in (successional) plant communities in The Netherlands. A key role for pathogenic nematodes in cyclic succession in grazed grassland confirmed similar results in

  13. 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...

  14. 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...

  15. Successes and failures in the use of parasitic nematodes for pest control

    NARCIS (Netherlands)

    Georgis, R.; Koppenhöfer, A.M.; Lacey, L.A.; Bélair, G.; Duncan, L.W.; Grewal, P.S.; Samish, M.; Tan, L.; Torr, P.; Tol, van R.W.H.M.

    2006-01-01

    Advances in mass-production and formulation technology of entomopathogenic nematodes, the discovery of numerous isolates/strains and the desirability of reducing pesticide usage have resulted in a surge of scientific and commercial interest in these nematodes. The lessons learned from earlier

  16. Molecular characterization of the beet cyst nematode (Heterodera schachtii) resistance locus Hs1.

    NARCIS (Netherlands)

    Salentijn, E.M.J.

    1995-01-01

    The white beet cyst nematode (BCN), Heterodera schachtii Schm. is a serious pest in sugar beet ( B. vulgaris L.) cultivation and is widely distributed throughout most of the beet-growing areas in the world (Cooke 1987). The economical losses due to infestation with the nematode are considerable (app

  17. Multiple species-specific controls of root-feeding nematodes in natural soils

    NARCIS (Netherlands)

    Piskiewicz, A.M.; Duyts, H.; Putten, van der W.H.

    2008-01-01

    One of the major limitations to enhance sustainability of crop production systems is the inability to control root-feeding nematodes without using chemical biocides. In soils under wild vegetation, however, root-feeding nematodes affect plant performance and plant community composition varying from

  18. Biological control of Otiorhynchus sulcatus by insect parasitic nematodes, Heterorhabditis spp. at low temperatures.

    NARCIS (Netherlands)

    Westerman, P.R.

    1997-01-01

    The black vine weevil, Otiorhynchus sulcatus, is an important pest in ornamentals and nursery stock in The Netherlands. The larvae, which feed on the root system of the plant, can be controlled by insect parasitic nematodes, Heterorhabditis. However, the presently available isolates of the nematode

  19. 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 47

  20. Post-Plant nematicides for the control of root lesion nematode in red raspberry

    Science.gov (United States)

    There are currently few registered post-plant nematicides available to control root lesion nematode (Pratylenchus penetrans, RLN) in red raspberry (Rubus ideaus). The rate of raspberry decline due to RLN depends upon the nematode population density but usually occurs over a 3- to 4-year period. To ...

  1. The discovery of fluazaindolizine: A new product for the control of plant parasitic nematodes.

    Science.gov (United States)

    Lahm, George P; Desaeger, Johan; Smith, Ben K; Pahutski, Thomas F; Rivera, Michel A; Meloro, Tony; Kucharczyk, Roman; Lett, Renee M; Daly, Anne; Smith, Brenton T; Cordova, Daniel; Thoden, Tim; Wiles, John A

    2017-04-01

    Fluazaindolizine is a new highly effective and selective product for the control of plant parasitic nematodes. Specificity for nematodes coupled with absence of activity against the target sites of commercial nematicides suggests that fluazaindolizine has a novel mode of action. The discovery, structure-activity development and biological properties for this new class of nematicides are presented.

  2. A PCR test to detect the cereal root-knot nematode Meloidogyne naasi

    NARCIS (Netherlands)

    Zijlstra, C.; Hoof, van R.A.; Donkers-Venne, D.

    2004-01-01

    The cereal root-knot nematode Meloidogyne naasi can cause serious cereal crop losses. The nematode is also found in agricultural fields where non-host crops are grown. Control of M. naasi can be based on preventing its spread, host resistance and crop management as well as on the design of crop rota

  3. Impact of grapevine (Vitis vinifera) varieties on reproduction of the northern root-knot nematode (Meloidogyne hapla)

    Science.gov (United States)

    Plant-parasitic nematodes are microscopic soil worms that attack the roots of grape plants and cause yield loss. One of the most commonly encountered plant-parasitic nematodes in eastern Washington Vitis vinifera vineyards is Meloidogyne hapla, the northern root-knot nematode. The selection of plant...

  4. Synthesis of Nitrogen-Containing Derivatives from a-Pinene and Their Nematicidal Activity against Pinewood Nematode%α-蒎烯含氮衍生物的合成及其杀松材线虫活性的研究

    Institute of Scientific and Technical Information of China (English)

    杨益琴; 王石发; 李艳苹; 袁冬菊; 赵博光; 谷文; 叶建仁

    2009-01-01

    A series of imine and amine derivatives were synthesized from a-pinene by hydroboronation, oxidation, amination, and selective reduction. The nematicidal activities of 3-pinanimines and 3-pinanamines were examined by the bioassay. Furthermore, the chemical structures of synthesized imines and amines were characterized based on FT-IR, ~1H NMR, ~(13)C NMR and GC-MS. The bioassay results showed that N-phenyl-3-pinanimine had the strongest nematicidal activity and it is very possible to commer-cialize because its nematicidal effects after 24, 48, and 72 h reached 89.28%, 89.58% and 95.75%, respec-tively when the level of N-phenyl-3-pinanimine was 1× 10~(-3)μL/mL (about 1 ×10~(-3) mg/mL).%以α-蒎烯为原料,经硼氢化-氧化、胺化及选择性还原等步骤合成了系列3-蒎酮亚胺和3-蒎胺类化合物,探索了3-蒎酮亚胺和3-蒎胺的不同结构与杀松材线虫活性的关系.采用FT-IR,~1H NMR,~(13)C NMR,GC-MS等分析手段对蒎酮亚胺和蒎胺类化合物的结构进行了表征.结果表明:N-苯基-3-蒎酮亚胺具有很强的杀松材线虫活性,在1× 10~(-3)μL/mL(约1×10~(-3) mg/mL)浓度下,在24,48和72 h内杀线虫效率分别达到89.28%,89.58%和95.75%,该化合物极具开发潜力.

  5. 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.

  6. Effects of gastrointestinal nematode infection on the ruminant immune system.

    Science.gov (United States)

    Gasbarre, L C

    1997-11-01

    Gastrointestinal (GI) nematodes of ruminants evoke a wide variety of immune responses in their hosts. In terms of specific immune responses directed against parasite antigens, the resulting immune responses may vary from those that give strong protection from reinfection after a relatively light exposure (e.g. Oesophagostomum radiatum) to responses that are very weak and delayed in their onset (e.g. Ostertagia ostertagi). The nature of these protective immune responses has been covered in another section of the workshop and the purpose of this section will be to explore the nature of changes that occur in the immune system of infected animals and to discuss the effect of GI nematode infections upon the overall immunoresponsiveness of the host. The discussion will focus primarily on Ostertagia ostertagi because this parasite has received the most attention in published studies. The interaction of Ostertagia and the host immune system presents what appears to be an interesting contradiction. Protective immunity directed against the parasite is slow to arise and when compared to some of the other GI nematodes, is relatively weak. Although responses that reduce egg output in the feces or increase the number of larvae undergoing inhibition may occur after a relatively brief exposure (3-4 months), immune responses which reduce the number of parasites that can establish in the host are not evident until the animal's second year. Additionally, even older animals that have spent several seasons on infected pastures will have low numbers of Ostertagia in their abomasa, indicating that sterilizing immune responses against the parasite are uncommon. In spite of this apparent lack of specific protective immune responses, infections with Ostertagia induce profound changes in the host immune system. These changes include a tremendous expansion of both the number of lymphocytes in the local lymph nodes and the number of lymphoid cells in the mucosa of the abomasum. This expansion

  7. Soil and freshwater nematodes of the Iberian fauna: A synthesis

    Directory of Open Access Journals (Sweden)

    Peña-Santiago, R.

    2006-12-01

    Full Text Available The first available compilation of Iberian soil and freshwater nematodes is presented in this paper. The inventory is currently made up of 981 species belonging to 236 genera, 77 families and 12 orders. Data of the Iberian nematode fauna are compared with other components of the Iberian biota, as well as the nematode fauna of other geographical regions. Quantitative and qualitative aspects of the nematode inventory are analyzed and discussed, paying special attention to the kind of information available for each species, and concluding that practically one-third of Iberian species are deficiently characterized and need further study. Endemicity of Iberian species is also considered: 143 species, 14.6% of the total, are restricted (in their distribution to the Iberian geography, most of them being members of the orders Dorylaimida (87 and Tylenchida (29, which are also the most diversified nematode taxa. Practical or applied interest of knowledge of the Iberian nematode fauna is commented and supported with examples and recent contributions. Finally, an alphabetical list of the species, ordered by specific name, is provided.

    En esta contribución se presenta una recopilación de las especies ibéricas de nematodos de suelo y de agua dulce, la primera de este tipo realizada hasta el momento. El inventario actual lo componen 981 especies de 236 géneros, 77 familias y 12 órdenes. Los datos correspondiente a la fauna ibérica de nematodos se compara con la de otros táxones de la biota ibérica. Se analizan y se discuten distintos aspectos cuantitativos y cualitativos de la fauna nematológica, con especial énfasis en el tipo de información disponible sobre cada especie, y se concluye que casi una tercera parte de las especies ibéricas permanecen insuficientemente caracterizadas, razón por la cual requieren de estudios adicionales. La endemicidad de las especies es así mismo objeto de atención: 143 especies, un 14.6% del total est

  8. Long-term effects of plant diversity and composition on soil nematode communities in model grasslands.

    Science.gov (United States)

    Viketoft, Maria; Bengtsson, Janne; Sohlenius, Björn; Berg, Matty P; Petchey, Owen; Palmborg, Cecilia; Huss-Danell, Kerstin

    2009-01-01

    An important component of plant-soil feedbacks is how plant species identity anddiversity influence soil organism communities. We examine the effects of grassland plant species growing alone and together up to a richness of 12 species on nematode diversity and feeding group composition, eight years after the establishment of experimental grassland plots at the BIODEPTH site in northern Sweden. This is a substantially longer time than most other experimental studies of plant effects on soil fauna. We address the hypotheses that (la) higher species or functional diversity of plants increases nematode diversity, as well as influences nematode community composition. Alternatively, (1b) individual plant species traits are most important for nematode diversity and community composition. (2) Plant effects on soil organisms will decrease with increasing number of trophic links between plants and soil fauna. Plant species identity was often more important than plant diversity for nematode community composition, supporting hypothesis 1b. There was a weak positive relation between plant and nematode richness;which could be attributed to the presence of the legume Trifolium pratense, but also to some other plant species, suggesting a selection or sampling effect. Several plant species in different functional groups affected nematode community composition. For example, we found that legumes increased bacterial-feeding nematodes, most notably r-selected Rhabditida, while fungal-feeding nematodes were enhanced by forbs. Other bacterial feeders and obligate root feeders were positively related to grasses. Plant effects were usually stronger on plant-, bacterial- and fungal-feeding nematodes than on omnivores/predators, which supports hypothesis 2. Our study suggests that plant identity has stronger effects than plant diversity on nematode community composition, but when comparing our results with similar previous studies the effects of particular plant species appear to vary. We

  9. Localization of Transmissible and Nontransmissible Viruses in the Vector Nematode Xiphinema americanum.

    Science.gov (United States)

    Wang, Shouhua; Gergerich, Rose C; Wickizer, Sandra L; Kim, Kyung S

    2002-06-01

    ABSTRACT The inner lining of the food canal of nematodes that transmit plantinfecting viruses is regarded as the retention region of viruses. To characterize the location of transmissible and nontransmissible viruses in the vector nematode Xiphinema americanum, three nepoviruses, Tobacco ringspot virus (TRSV), Tomato ringspot virus(TomRSV), and Cherry leaf roll virus(CLRV), and one non-nematode-transmissible virus, Squash mosaic virus (SqMV), were evaluated for transmission efficiency and localization sites in the nematode. Transmission trials showed highest transmission efficiency for TomRSV (38% with 1 and 100% with 10 nematodes, respectively), intermediate efficiency for TRSV (27% with 1 and 65% with 10 nematodes, respectively), and no transmission for CLRV and SqMV. Electron microscopy and immunofluorescent labeling revealed that TRSV was primarily localized to the lining of the lumen of the stylet extension and the anterior esophagus, but only rarely in the triradiate lumen. Within a nematode population, particles of TRSV were no longer observed in these three regions 10 weeks after acquisition, and it is assumed that there was gradual and random loss of the virus from these areas. The percentage of nematodes that were labeled by virus-specific immunofluorescent labeling in a population of viruliferous nematodes decreased gradually after TRSV acquisition when the nematodes were placed on a nonhost of the virus, and the loss of immunofluorescent labeling paralleled the decrease in the ability of the nematode population to transmit the virus. TomRSV was localized only in the triradiate lumen based on thin-section electron microscopy. No virus-like particles were observed in any part of the food canal of nematodes that had fed on CLRV-infected plants. Virus-like particles that appeared to be partially degraded were observed only in the triradiate lumen of nematodes that had fed on SqMV-infected plants. These results clarified the status of localization of two

  10. Effect of free-air CO2 enrichment on nematode communities in a Chinese farmland ecosystem

    Institute of Scientific and Technical Information of China (English)

    LI Qi; LIANG Wen-ju; JIANG Yong; ZHU Jian-guo; KONG Chui-hua

    2005-01-01

    At a rice-wheat rotational free-air CO2 enrichment(FACE) platform, the effect of elevated atmospheric CO2 on soil nematode communities in a farmland ecosystem was studied. Wheat plots were exposed to elevated atmospheric CO2 (ambient 370 μl/L + 200 μl/L).32 families and 40 genera of nematode were observed in soil suspensions during the study period. Under FACE treatment, the numbers of total nematodes, bacterivores and fungivores exhibited an increasing trend. Because of the seasonal variation of soil temperature and moisture, the effectof elevated atmospheric CO2 on soil nematodes was only observed under favorable conditions. The response of nematode communities to elevated atmospheric CO2 may indicate the change of soil food web.

  11. '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...

  12. Influence of different fertilizer types of zucchini (Cucurbita pepo) on the structure of nematode communities.

    Science.gov (United States)

    Haytova, D; Bileva, T

    2011-01-01

    Increasing efficiency of production of vegetable crops is directly related to search for appropriate solution to increase their productivity. Organic amendments have been used for centuries to improve soil fertility and crop yield. Our study suggests that organic amendments can also be used as nematicidal agents. The survey was conducted on Experimental field of Department Horticulture at Agricultural University of Plovdiv, Bulgaria in 2009 on nematode infested sites. Combination with two types of fertilizers was used to investigate their effects on the community of soil nematodes. Characterization and comparative analysis among treatments of soil nematode community structure based on different ecological measures such as total nematode abundance, number of genera, trophic diversity and etc., was made. Changes in the composition and structure of nematode community as result of different fertilizer types were assessed.

  13. Orsay, Santeuil and Le Blanc viruses primarily infect intestinal cells in Caenorhabditis nematodes.

    Science.gov (United States)

    Franz, Carl J; Renshaw, Hilary; Frezal, Lise; Jiang, Yanfang; Félix, Marie-Anne; Wang, David

    2014-01-05

    The discoveries of Orsay, Santeuil and Le Blanc viruses, three viruses infecting either Caenorhabditis elegans or its relative Caenorhabditis briggsae, enable the study of virus-host interactions using natural pathogens of these two well-established model organisms. We characterized the tissue tropism of infection in Caenorhabditis nematodes by these viruses. Using immunofluorescence assays targeting proteins from each of the viruses, and in situ hybridization, we demonstrate viral proteins and RNAs localize to intestinal cells in larval stage Caenorhabditis nematodes. Viral proteins were detected in one to six of the 20 intestinal cells present in Caenorhabditis nematodes. In Orsay virus-infected C. elegans, viral proteins were detected as early as 6h post-infection. The RNA-dependent RNA polymerase and capsid proteins of Orsay virus exhibited different subcellular localization patterns. Collectively, these observations provide the first experimental insights into viral protein expression in any nematode host, and broaden our understanding of viral infection in Caenorhabditis nematodes.

  14. In vitro effect of condensed tannin extract from acacia (Acacia mearnsii) on gastrointestinal nematodes of sheep.

    Science.gov (United States)

    Minho, Alessandro P; Bueno, Ives Cláudio Da S; Gennari, Solange Maria; Jackson, Frank; Abdalla, Adibe Luiz

    2008-09-01

    The aim of this study was to determine the inhibitory effects of condensed tannin extract from acacia on the feeding of first-stage larvae (L1) of Haemonchus contortus, Trichostrongylus vitrinus and Teladorsagia circumcincta. The experiment was developed such that the inhibition of feeding for each of the nematode species could be evaluated. L1 recovered from fecal samples from a donor with monospecific infection was incubated in several dilutions of acacia extract (AE). The LD50 was determined for the three species of nematodes. Polyethylene glycol (PEG) was added to all dilutions of AE to inactivate the condensed tannins (CT) from acacia and to confirm their effects on L1. The impact of CT on larval feeding inhibition was detected for all the species of nematodes (H. contortus, T. colubriformis and T. circumcincta). There were differences between the aqueouswater control and CT treated groups (P nematodes studied could be used as an alternative means for controlling nematodes in sheep.

  15. Influence of industrial heavy metal pollution on soil free-living nematode population.

    Science.gov (United States)

    Pen-Mouratov, Stanislav; Shukurov, Nosir; Steinberger, Yosef

    2008-03-01

    The effect of distance from a heavy metal pollution source on the soil nematode community (trophic structure, sex structure, and taxa composition) was investigated along a 15-km transect originating at the Almalyk Industrial Complex, Uzbekistan (pollution source). The soil nematode community was exposed to heavy metal influence both directly and through soil properties changes. Pollution effect on the density and biomass of soil free-living nematodes was found to be highest at pollution source, with fungivores and plant parasites dominating at the upper and deeper soil layers next to the pollution source. These groups decreased along the transect, yielding domination to bacteria- and fungi-feeders. The sex ratio of nematode communities was found to be dependent on heavy metal pollution levels, with the juveniles being the most sensitive nematode group. The Maturity and modified Maturity Indices, reflecting the degree of disturbance of the soil ecosystem, were found to be the most sensitive indices.

  16. Serological Differentiation of Plant-parasitic Nematode Species with Polyclonal and Monoclonal Antibodies.

    Science.gov (United States)

    Schots, A; Gommers, F J; Bakker, J; Egberts, E

    1990-01-01

    Although several attempts have been made to differentiate nematode species with polyclonal antisera, these efforts thus far have met with limited success because of extensive crossreactivities of the sera. Since the hybridoma technique offers the opportunity to develop more specific serological reagents, some research groups have recently started to apply this technology to the problem of species identification in nematology. Monoclonal antibodies (MA) that differentiate the potato-cyst nematodes Globodera rostochiensis and G. pallida, as well as MA specific for Meloidogyne species, have been developed. The possibilities of developing serodiagnostic tools for identification of nematodes recovered from soil samples and the implications of such monitoring of nematode infestations in view of integrated control of plant-parasitic nematodes are discussed.

  17. Effects of vegetation coverage on the spatial distribution of soil nematode trophic groups

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The spatial variability of total soil nematodes and trophic groups in bare and fallow plots in Shenyang Experi-mental Station of Ecology, Chinese Academy of Sciences was examined using geostatistics combined with classic statistics. Results showed that the soil pH value had a negative effect on plant-parasites in both bare and fallow plots; the mean number of total nematodes was significantly higher in fallow plots than in bare plots, which was 1485.3 and 464.0 individuals per 100 g dry soil in fallow and bare plots, respectively; the nugget (C0)/sill (C0+C) ratio of total nematodes, plant-parasites and bacterivores were lower in fallow plots (27.3%-45.6%) than in bare plots (49.5%-100%); the spatial distribution of total nematodes and trophic groups was found to be different between fallow and bare plots, which indicated that vegetation coverage had an effect on soil nematodes.

  18. Granular Nematicides as Adjuncts to Fumigants for Control of Cotton Root-knot Nematodes.

    Science.gov (United States)

    Jorgenson, E C

    1979-04-01

    Growth and yield of cotton were best with combinations of fumigants and organophosphate and carbamate nematicides. Organophosphates or carbamates used alone did not give season-long control of root-knot nematodes. Long-term control was poor because the temporary sublethal effects of these materials diminished soon enough lhat the nematodes could reproduce. The nematodes survived the treatments and a year of nonhost culture, and damaged a susceptible host crop 2 years after treatment. No such damage occurred in plots treated with fumigant, fumigant plus organophosphate, or fumigant plus carbamate. Treatment of seed and treatment of cotton, either in furrow at planting or sidedressing at midseason, with organophosphate and carbamate nematicides resulted in little or no yield increase, because nematode control was only minimal and temporary; or in a yield decrease, because the toxicity of the materials was manifested when nematode populations were low.

  19. Distribution of plant-parasitic nematodes on sugarcane in louisiana and efficacy of nematicides.

    Science.gov (United States)

    Bond, J P; McGawley, E C; Hoy, J W

    2000-12-01

    A survey conducted from May 1995 through August 1998 revealed diverse nematode communities in Louisiana sugarcane fields. High populations of Mesocriconema, Paratrichodorus, Pratylenchus, and Tylenchorhynchus were widespread in nine sugarcane production parishes. Comparisons of plant cane and ratoon sugarcane crops indicated that nematode community levels increase significantly in successive ratoon crops. Nematicide trials evaluated the efficacy of aldicarb, ethoprop, and phorate against indigenous nematode populations. Aldicarb consistently increased the number of millable stalks, cane tonnage, and yield of sucrose in soils with a high sand content. Yield increases were concomitant with reductions in the density of the nematode community shortly after planting and at harvest. In soils with a higher clay content, the chemicals were less effective in controlling nematode populations and, as a result, yield increases were minimal.

  20. Treatment of Nematodes with Ozone Gas: A Sustainable Alternative to Nematicides

    Science.gov (United States)

    Msayleb, Nahed; Ibrahim, Saiid

    This study tests Ozone as a Nematicides' alternative. Nematode-infected soil samples were treated with ascending doses of O3 by submerging the outlet of an "MB1000 Ozone Generator" in the 40 ml samples; then to test the O3 nematicidal effect by gas fumigation, Ozone gas was released into a sealed bag containing 80 g of each of the 6 nematode-infected soil samples with ascending doses and a repetition of each. With water-ozonation, 900 mg O3 were needed to kill 100% of nematodes, and the O3-Nematodes LD50 was identified by 420 mg. With the second experiment, O3 soil fumigation for 50 minutes at a dose of 1,125 mg in an air volume of 5 litres, were needed to control 95% of living nematodes.

  1. Transcriptomic analysis of the entomopathogenic nematode Heterorhabditis bacteriophora TTO1

    Directory of Open Access Journals (Sweden)

    Spieth John

    2009-04-01

    Full Text Available Abstract Background The entomopathogenic nematode Heterorhabditis bacteriophora and its symbiotic bacterium, Photorhabdus luminescens, are important biological control agents of insect pests. This nematode-bacterium-insect association represents an emerging tripartite model for research on mutualistic and parasitic symbioses. Elucidation of mechanisms underlying these biological processes may serve as a foundation for improving the biological control potential of the nematode-bacterium complex. This large-scale expressed sequence tag (EST analysis effort enables gene discovery and development of microsatellite markers. These ESTs will also aid in the annotation of the upcoming complete genome sequence of H. bacteriophora. Results A total of 31,485 high quality ESTs were generated from cDNA libraries of the adult H. bacteriophora TTO1 strain. Cluster analysis revealed the presence of 3,051 contigs and 7,835 singletons, representing 10,886 distinct EST sequences. About 72% of the distinct EST sequences had significant matches (E value H. bacteriophora, among which are those encoding F-box-like/WD-repeat protein theromacin, Bax inhibitor-1-like protein, and PAZ domain containing protein. Gene Ontology terms were assigned to 6,685 of the 10,886 ESTs. A total of 168 microsatellite loci were identified with primers designable for 141 loci. Conclusion A total of 10,886 distinct EST sequences were identified from adult H. bacteriophora cDNA libraries. BLAST searches revealed ESTs potentially involved in parasitism, RNA interference, defense responses, stress responses, and dauer-related processes. The putative microsatellite markers identified in H. bacteriophora ESTs will enable genetic mapping and population genetic studies. These genomic resources provide the material base necessary for genome annotation, microarray development, and in-depth gene functional analysis.

  2. Lung and hearth nematodes in some Spanish mammals.

    Science.gov (United States)

    Alvarez, F; Iglesias, R; Bos, J; Rey, J; Sanmartin Durán, M L

    1991-01-01

    Thirteen host species belonging to the orders Rodentia, Insectivora and Carnivora from various localities in Galicia (NW Spain) were examined for heart and lung parasites. The following species were found: Parastrongylus dujardini (5.5%) in Apodemus sylvaticus, Crenosoma striatum in Erinaceus europaeus (83%), Angiostrongylus vasorum, Crenosoma vulpis and Eucoleus aerophilus in Vulpes vulpes (3, 3.46 and 0.50%, respectively), Crenosoma taiga in Putorius putorius (100%) and Crenosoma sp. in Meles meles (25%). In Crocidura russula nematode larvae were found (3.3%). Mus musculus, Rattus norvegicus, Rattus rattus, Talpa caeca, Sorex araneus, Genetta genetta and Canis lupus were not parasitized by lung or heart parasites.

  3. Nematode community structure in the vicinity of a metallurgical factory.

    Science.gov (United States)

    Salamún, Peter; Renčo, Marek; Miklisová, Dana; Hanzelová, Vladimíra

    2011-12-01

    Soil nematode communities (taxa composition, trophic structure, ecological indices) in the area of metallurgical factory (Oravské ferozliatinárske závody) in Široká, Northern Slovakia were investigated in 2009. The factory belongs to main sources of emissions originated by ferroalloy production in this region. Four sites (meadows) were selected in a downwind direction from the factory: site A was located 0.85 km far from the factory, and the other sites were maintained in approximately 2-km intervals from each other. Chemical analysis of soil samples showed low concentrations of heavy metals (As, Cd, Cr, Cu, Ni, Pb and Zn), with all values being under Slovak limit concentrations of heavy metals in soils. Only the Cd content in the soil sample from site A slightly exceeded the allowable threshold, but it was decreasing with the distance from the factory, similarly as remaining metals except Cr, with slightly increasing trend of concentration. Within 64 identified nematode genera, the Helicotylenchus, Paratylenchus, Pratylenchus, Acrobeloides, Cephalobus and Rhabditis were most common and eudominant. This was clearly reflected on the trophic structure of nematode communities, where plant feeding nematodes and bacteriovorous prevailed. Significant negative correlation (P < 0.05) was observed between the abundance of bacteriovores and the concentration of Cu in the soil. On the other hand, fungivores showed significant correlation with Ni and Cr (P < 0.05) as well as predators with Cd, Pb and Zn contents in the soil (P < 0.01). The highly significant correlation (P < 0.05; P < 0.01) was found between As, Cd, Ni, Pb and Zn and Maturity Index 2-5. A negative relationship was detected between Maturity Index and the concentration of Cr in the soil (P < 0.01). On the other hand, Cu was in positive correlation with MI values. The MI, reflecting the degree of disturbances and changes in the structure and function of the soil ecosystem, was found

  4. Evaluation the effect of albendazole against nematodes in sheep

    Directory of Open Access Journals (Sweden)

    M. I. Al-Farwachi

    2008-01-01

    Full Text Available Six sheep farms in Mosul city, Iraq randomly selected, were surveyed for gastrointestinal nematodes resistant to Albendazole. On each of 6 sheep farms, 20 lambs were randomly distributed into two equal groups untreated control group, and albendazole (benzimidazole group (10 mg/kg BW. Faecal egg counts and larval cultures were done at 7, 14, and 21 days after anthelmintic treatment. Resistance was apparent for albendazole on 4 farms out of 6 (66.7%. Post-treatment larval cultures indicated: Strongyloides papillosus, Marshalligia marshalli, Nematodirus spathiger and Haemonchus contortus.

  5. Anthelmintic resistance in cattle nematodes in the US.

    Science.gov (United States)

    Gasbarre, Louis C

    2014-07-30

    The first documented case of macrocyclic lactone resistance in gastrointestinal (GI) nematodes of cattle was seen in the US approximately 10 years ago. Since that time the increase incidence of anthelmintic resistance has continued at an alarming rate. Currently parasites of the genera Cooperia and/or Haemonchus resistant to generic or brand-name macrocyclic lactones have be demonstrated in more than half of all operations examined. Both of these parasite genera are capable of causing economic losses by decreasing food intake and subsequently animal productivity. Currently, there are no easy and quick means to detect anthelmintic resistant GI nematodes. Definitive identification requires killing of cattle. The most commonly used field detection method is the fecal egg count reduction test (FECRT). This method can be adapted for use as a screening agent for Veterinarians and producers to identify less than desired clearance of the parasites after anthelmintic treatment. Further studies can then define the reasons for persistence of the egg counts. The appearance of anthelmintic resistance is largely due to the development of very effective nematode control programs that have significantly improved the productivity of the US cattle industry, but at the same time has placed a high level of selective pressure on the parasite genome. The challenges ahead include the development of programs that control the anthelmintic resistant nematodes but at the same time result in more sustainable parasite control. The goal is to maintain high levels of productivity but to exert less selective pressures on the parasites. One of the most effective means to slow the development of drug resistance is through the simultaneous use of multiple classes of anthelmintics, each of which has a different mode of action. Reduction of the selective pressure on the parasites can be attained through a more targeted approach to drug treatments where the producer's needs are met by selective

  6. Cadmium toxicity in the free-living nematode, Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Popham, J.D.; Webster, J.M.

    1979-10-01

    The effect of cadmium on the fecundity, growth, and fine structure of the free-living nematode Caenorhabditis elegans was studied. High concentrations of cadmium significantly decreased the fecundity and growth of these organisms. Electron microscopy showed that cadmium modifies the structure of the mitochondria in the esophagus and intestine, causes the formation of inclusion bodies in the nucleus of esophageal cells, and alters the morphology of cytosomes in the intestinal cells. The results suggest that the decreased fecundity and growth of cadmium-exposed C. elegans may be due to cadmium interfering with nutrient uptake or assimilation or both.

  7. Motility of small nematodes in wet granular media

    CERN Document Server

    Juarez, G; Sznitman, J; Arratia, P E

    2010-01-01

    The motility behavior of the \\textit{Caenorhabditis elegans} is investigated in wet granular medium as a function of area density ($\\phi$) and dispersity. Surprisingly, the locomotion speed increases in granular media compared to free swimming. The surrounding structure of the medium leads to enhanced undulatory propulsion due to its ability to sustain a finite shear stress and convert lateral force into forward motion. For $\\phi > 0.55$, the nematode is observed to change its gate from swimming to crawling in polydisperse media \\textit{only}. This highlights the subtle difference in local structure between media.

  8. Tangling of Tethered Swimmers: Interactions between Two Nematodes

    Science.gov (United States)

    Backholm, Matilda; Schulman, Rafael D.; Ryu, William S.; Dalnoki-Veress, Kari

    2014-09-01

    The tangling of two tethered microswimming worms serving as the ends of "active strings" is investigated experimentally and modeled analytically. C. elegans nematodes of similar size are caught by their tails using micropipettes and left to swim and interact at different separations over long times. The worms are found to tangle in a reproducible and statistically predictable manner, which is modeled based on the relative motion of the worm heads. Our results provide insight into the intricate tangling interactions present in active biological systems.

  9. Influence of plant-parasitic nematodes on longleaf pine seedlings.

    Science.gov (United States)

    Ruehle, J L

    1973-01-01

    Seedlings of longleaf pine (Pinus palustris) were grown in 20-cm pots for 5 to 7 months in the greenhouse following inoculation with a high or low level of one of seven species of plant-parasitic nematodes. Belonolaimus longicaudatus and Helicotylenchus dihystera had no effect on seedling growth. High inoculum densities of Hoplolaimus galeatus and Tylenchorhynchus claytoni caused a significant reduction of fresh weight of seedling roots. Root and top weights of seedlings grown in soil infested with Meloidodera floridensis or Pratylenchus brachyurus were significantly less than those of seedlings in noninfested soil. Root growth of seedlings was stimulated by the higher inoculum density of Scutellonema brachyurum.

  10. Four acetylcholinesterase genes in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Arpagaus, M; Combes, D; Culetto, E; Grauso, M; Fedon, Y; Romani, R; Toutant, J P

    1998-01-01

    Whereas a single gene encodes acetylcholinesterase (AChE) in vertebrates and most insect species, four distinct genes have been cloned and characterized in the nematode Caenorhabditis elegans. We found that ace-1 (mapped to chromosome X) is prominently expressed in muscle cells whereas ace-2 (located on chromosome I) is mainly expressed in neurons. Ace-x and ace-y genes are located in close proximity on chromosome II where they are separated by only a few hundred base pairs. The role of these two genes is still unknown.

  11. A pathogenic nematode targets recognition proteins to avoid insect defenses.

    Directory of Open Access Journals (Sweden)

    Duarte Toubarro

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

  12. A pathogenic nematode targets recognition proteins to avoid insect defenses.

    Science.gov (United States)

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

    2013-01-01

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

  13. PLANT-PARASITIC NEMATODES ON STONE FRUITS AND CITRUS IN LEBANON

    Directory of Open Access Journals (Sweden)

    Said K. Ibrahim

    2016-06-01

    Full Text Available Ibrahim Said K., Ibrahim Azar, Christian Naser, Badran Akikki and Ludmilla Ibrahim. 2016. Plant-parasitic nematodes on stone fruits and citrus in Lebanon. Lebanese Science Journal, 17(1: 9-24. This study aimed to determine the occurrence, distribution of plant parasitic nematodes on stone fruits in Lebanon and to determine the effect of plant extracts on the mortality of several nematode species. A total of 308 soil samples were collected from five different crops. Almost all surveyed areas showed infection with nematodes. The soil infestation rate with nematodes in collected soil samples from all 10 surveyed crops ranged from 66.6 to 100%. Eighteen out of 308 soil samples were free of nematodes (5.8%. All the collected soil samples from nectarine and plum orchards were infested with nematodes (100%, followed by citrus (97.6%, apple (88.7%, pear and quince (85.7%, and cherry (81.4%. The lowest infection (66.6% was detected on almond and apricot. The level of infestation varied from one area to another and ranged between 0.1 and 28 nematodes per 1 g of soil, with the highest number obtained on cherry. Several genera were identified based on morphological characters including: root-knot nematodes (Meloidogyne spp., Tylenchulus, Xiphinema, Rotylenchus, Pratylenchus, and Longidorus. Tylenchulus and Radopholus spp. were the most common on citrus trees, whereas Pratylechus and Meloidogyne spp. were detected almost in all the samples collected from all the crops. Six chopped aromatic plants were tested in pot experiments to control nematodes population densities. The results revealed that carbofuran (nematicide was the most effective (88.48% in comparison to the plant materials. Allium sativum gave the highest control (76.52% followed by Tageta patula (72.0%, Cucurbita maxima (71.84% and Inula viscosa (63.96%. Origanum syriacum (55.04% and Thymus (53.72% were less effective in comparison to the rest of tested plant materials.

  14. About the translation of Chinese name for"cyst nematode"%"Cyst nematode"中文译名应该为"孢囊线虫"

    Institute of Scientific and Technical Information of China (English)

    李红梅; 陈书龙; 郑经武; 肖炎农; 彭德良

    2011-01-01

    The cyst nematode diseases become the main thread to safe production of Chinese agriculture in recent years. The difference in Chinese translation about cyst nematode was appeared in some of scientific books and literatures. Therefore, the critical literature searching and discusses was carried out in order to support the accurate Chinese translation of cyst nematodes.%农作物孢囊线虫病害(crop cyst nematode diseases)近年来已经成为威胁我国农业生产安全的重要植物病原线虫病害,鉴于国内部分有关学术论著与文献中,对"cyst nematode"的中译名写法有歧义,作者通过文献的阐述与论证,认为"cyst nematode"的中译名称应该为"孢囊线虫",而不用"胞囊线虫",以免引起混乱.

  15. Lethal fighting in nematodes is dependent on developmental pathway: male-male fighting in the entomopathogenic nematode Steinernema longicaudum.

    Directory of Open Access Journals (Sweden)

    Annemie N R L Zenner

    Full Text Available Aggressive encounters occur between competitors (particularly males throughout the animal kingdom, and in some species can result in severe injury and death. Here we describe for the first time lethal interactions between male nematodes and provide evidence that the expression of this behaviour is developmentally controlled. Males of the entomopathogenic nematode Steinernema longicaudum coil around each other, resulting in injuries, paralysis and frequently death. The probability of death occurring between pairs of males was affected by the developmental pathway followed, being much greater among males that had passed through the infective juvenile (IJ, or dauer stage than among males that had not. Post-IJ males are found only in newly colonised hosts, typically with few competing males present. Killing those few competitors may secure valuable resources (both females and a host cadaver for nourishment of offspring. Non-IJ males develop in subsequent generations within a host cadaver, where the presence of many closely related male competitors increases the risk:benefit ratio of fighting. Thus, passage through the IJ stage primes males for enhanced aggression in circumstances where this is more likely to result in increased reproductive success. Fighting occurred between males developing in mixed-sex social groups, indicating that it is an evolved trait and not an abnormal response to absence of females. This is supported by finding high mortality of males, but not of females, across a range of population densities in insect cadavers. We propose that these nematodes, with their relatively simple organization, may be a useful model for studies of aggression.

  16. Population dynamics of host-specific root-feeding cyst nematode and resource quantity in the root zone of a clonal grass

    NARCIS (Netherlands)

    Stoel, C.D.; Duyts, H.; Putten, van der W.H.

    2006-01-01

    Recent studies have suggested that root-feeding nematodes influence plant community dynamics, but few studies have investigated the population dynamics of the nematodes. In coastal foredunes, feeding-specialist cyst nematodes (Heterodera spp.) are dominant in the soil nematode community and

  17. Population dynamics of a host-specific root-feeding cyst nematode and resource quantity in the root zone of a clonal grass

    NARCIS (Netherlands)

    Van der Stoel, C.D.; Duyts, H.; Van der Putten, W.H.

    2006-01-01

    Recent studies have suggested that root-feeding nematodes influence plant community dynamics, but few studies have investigated the population dynamics of the nematodes. In coastal foredunes, feeding-specialist cyst nematodes (Heterodera spp.) are dominant in the soil nematode community and

  18. Nematodes in the mallard (Anas platyrhynchos Linnaeus, 1758) and the common goldeneye (Bucephala clangula Linnaeus, 1758) (Anatidae) from Northern Europe.

    Science.gov (United States)

    Lebedeva, Daria I; Yakovleva, Galina A; Ieshko, Evgeny P

    2015-10-01

    There are first data on nematodes of Anas platyrhynchos Linnaeus, 1758 (mallard) and Bucephala clangula Linnaeus, 1758 (common goldeneye) from Northern Europe (Ladoga Lake region). The ducks were found to be infected with nine nematode species. A. platyrhynchos hosted eight nematode species and B. clangula was host to four nematode species. All species except Capillaria anatis were found in the region for the first time. Nematodes Amidostomum acutum, Streptocara crassicauda, and Tetrameres fissispina parasitized on both hosts and were the most abundant. The biggest number of parasites revealed was biohelminths with a direct life cycle.

  19. Caenorhabditis elegans: a simple nematode infection model for Penicillium marneffei.

    Directory of Open Access Journals (Sweden)

    Xiaowen Huang

    Full Text Available Penicillium marneffei, one of the most important thermal dimorphic fungi, is a severe threat to the life of immunocompromised patients. However, the pathogenic mechanisms of P. marneffei remain largely unknown. In this work, we developed a model host by using nematode Caenorhabditis elegans to investigate the virulence of P. marneffei. Using two P. marneffei clinical isolate strains 570 and 486, we revealed that in both liquid and solid media, the ingestion of live P. marneffei was lethal to C. elegans (P<0.001. Meanwhile, our results showed that the strain 570, which can produce red pigment, had stronger pathogenicity in C. elegans than the strain 486, which can't produce red pigment (P<0.001. Microscopy showed the formation of red pigment and hyphae within C. elegans after incubation with P. marneffei for 4 h, which are supposed to be two contributors in nematodes killing. In addition, we used C. elegans as an in vivo model to evaluate different antifungal agents against P. marneffei, and found that antifungal agents including amphotericin B, terbinafine, fluconazole, itraconazole and voriconazole successfully prolonged the survival of nematodesinfected by P. marneffei. Overall, this alternative model host can provide us an easy tool to study the virulence of P. marneffei and screen antifungal agents.

  20. Rogue sperm indicate sexually antagonistic coevolution in nematodes.

    Directory of Open Access Journals (Sweden)

    Ronald E Ellis

    2014-07-01

    Full Text Available Intense reproductive competition often continues long after animals finish mating. In many species, sperm from one male compete with those from others to find and fertilize oocytes. Since this competition occurs inside the female reproductive tract, she often influences the outcome through physical or chemical factors, leading to cryptic female choice. Finally, traits that help males compete with each other are sometimes harmful to females, and female countermeasures may thwart the interests of males, which can lead to an arms race between the sexes known as sexually antagonistic coevolution. New studies from Caenorhabditis nematodes suggest that males compete with each other by producing sperm that migrate aggressively and that these sperm may be more likely to win access to oocytes. However, one byproduct of this competition appears to be an increased probability that these sperm will go astray, invading the ovary, prematurely activating oocytes, and sometimes crossing basement membranes and leaving the gonad altogether. These harmful effects are sometimes observed in crosses between animals of the same species but are most easily detected in interspecies crosses, leading to dramatically lowered fitness, presumably because the competitiveness of the sperm and the associated female countermeasures are not precisely matched. This mismatch is most obvious in crosses involving individuals from androdioecious species (which have both hermaphrodites and males, as predicted by the lower levels of sperm competition these species experience. These results suggest a striking example of sexually antagonistic coevolution and dramatically expand the value of nematodes as a laboratory system for studying postcopulatory interactions.