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Теоретическая и прикладная нематология

Журнальные статьи

Anbesse, Samuel Ashebir; Strauch, Olaf; Ehlers, Ralf-Udo. Genetic improvement of the biological control nematode Heterorhabditis bacteriophora (Rhabditidomorpha: Heterorhabditidae): heterosis effect enhances desiccation but not heat tolerance //BIOCONTROL SCIENCE AND TECHNOLOGY Volume: 22 Issue: 9 Pages: 1035-1045 2012

The entomopathogenic nematode Heterorhabditis bacteriophora is commercially used in biological control of soil dwelling insect pests. It reproduces by autogamy (hermaphrodites) enabling the production of inbred lines, but also by amphimixis (through mating of male and female) which allows cross-breeding. When H. bacteriophora is produced in liquid culture, copulation of male and female is prevented and reproduction is solely by self-fertilisation of hermaphrodites. When reared in insects, crosses are possible resulting in heterozygous offspring. Heat and desiccation tolerance of these nematodes have been successfully improved by selective breeding. Trait deterioration was prevented by producing homozygous inbreds through consecutive reproduction in liquid culture, the method also used for commercial mass production. In this study, we investigated possible heterosis effects in desiccation and heat tolerance after cross-breeding of homozygous inbred lines of H. bacteriophora. Increased desiccation tolerance of the heterozygous progeny in comparison to homozygous inbred lines was recorded indicating that heterosis is a possible means for further improvement of this trait. In contrast, the heat tolerance of the heterozygous offspring was lower than that of the homozygous population. The results provide evidence for the tremendous potential of classical genetics to improve beneficial traits of a biological control agent and carry domestication of H. bacteriophora a significant step forward.

Andres, Maria Fe; Gonzalez-Coloma, Azucena; Sanz, Jesus; Nematicidal activity of essential oils: a review // PHYTOCHEMISTRY REVIEWS Volume: 11 Issue: 4 Special Issue: SI Pages: 371-390 DEC 2013

Plant parasitic nematodes are the most destructive group of plant pathogens worldwide and their control is extremely challenging. Plant Essential oils (EOs) and their constituents have a great potential in nematode control since they can be developed for use as nematicides themselves or can serve as model compounds for the development of derivatives with enhanced activity. This study reviews the plant Eos evaluated as potential nematicides and their toxic effects against pinewood nematode (Bursaphelenchusxylophilus) and root-knot nematodes (Meloidogyne spp.). Additionally, the nematicidal activity to M. javanica of several EOs from Spanish aromatic plants and their components is described.

Ballestriero, Francesco; Thomas, Torsten; Burke, Catherine;Identification of Compounds with Bioactivity against the Nematode Caenorhabditis elegans by a Screen Based on the Functional Genomics of the Marine Bacterium Pseudoalteromonas tunicata D2 //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 76 Issue: 17 Pages: 5710-5717 SEP 2010

Marine bacteria are a rich, yet underexplored, resource of compounds with inhibitory bioactivity against a range of eukaryotic target organisms. Identification of those inhibitors, however, requires a culturable or genetically tractable producer strain, a prerequisite that is not often fulfilled. This study describes a novel functional genomic screen that is based on expression of inhibitors in a heterogeneous recombinant host (i.e., Escherichia coli). Functional libraries were screened by selective grazing by the nematode Caenorhabditis elegans, in a simple, rapid, high-throughput manner. We applied our approach to discover inhibitors of C. elegans produced by the marine bacterium Pseudoalteromonas tunicata D2, a model organism for exploring a range of antagonistic activities between bacteria and eukaryotes and a known producer of several toxic compounds. Expression of P. tunicata DNA in E. coli and grazing selection by the nematode Caenorhabditis elegans identified two clones, with slow-and fast-killing modes of action. Genomic analysis of the slow-killing clone revealed that the activity was due to a small molecule, tambjamine, while the fast-killing activity involved a gene encoding for a novel protein. Microscopic analysis showed substantial colonization of the intestinal lumen, or rapid death of the nematode without colonization, for the two activities, respectively. The novel functional genomic screen presented here therefore detects new eukaryotic inhibitors with different chemical structures, kinetics, and predicted modes of actions.

Batalla-Carrera, Laia; Morton, Ana; Santamaria, Sergi; et al.Isolation and virulence of entomopathogenic fungi against larvae of hazelnut weevil Curculio nucum (Coleoptera, Curculionidae) and the effects of combining Metarhizium anisopliae with entomopathogenic nematodes in the laboratory //BIOCONTROL SCIENCE AND TECHNOLOGY Volume: 23 Issue: 1 Pages: 101-125 JAN 1 2013

An approach to ensure effective pest biocontrol would be to select native isolates of biological control agents (BCAs). A survey to isolate entomopathogenic fungi (EPF) from a hazelnut growing area has been carried out. EPF were recovered from 133 of the 295 soil samples. The main species isolated were Metarhizium anisopliae sensu lato (36%) and Beauveria bassiana sensu lato (42.8%). With regard to controlling abiotic factors, altitude had an effect on the distribution of B. bassiana, but not on M. anisopliae. Cropping system did not have an effect on the occurrence of these EPF, while pH appeared as a predictive variable for both. In addition, we tested the virulence of six of these isolates: three M. anisopliae and three of B. bassiana against larvae of Curculio nucum L. The highest larval mortality (reaching 80%) was due to M. anisopliae (strain 34) when applied in simultaneous combination with four entomopathogenic nematode species: Steinernema carpocapsae (strain B14), Steinernema feltiae (strain D114), Steinernema. sp. (strain D122) and Heterorhabditis bacteriophora (strain DG46). The effect of nematodes was greater and no antagonistic or synergistic effects were observed.

Blok, Vivian C.; Jones, John T.; Phillips, Mark S.; et al.Parasitism genes and host range disparities in biotrophic nematodes: the conundrum of polyphagy versus specialisation //BIOESSAYS Volume: 30 Issue: 3 Pages: 249-259 MAR 2008

This essay considers biotrophic cyst and root-knot nematodes in relation to their biology, host–parasite interactions and molecular genetics. These nematodes have to face the biological consequences of the physical constraints imposed by the soil environment in which they live while their hosts inhabit both above and below ground environments. The two groups of nematodes appear to have adopted radically different solutions to these problems with the result that one group is a host specialist and reproduces sexually while the other has an enormous host range and reproduces by mitotic parthenogenesis. We consider what is known about the modes of parasitism used by these nematodes and how it relates to their host range, including the surprising finding that parasitism genes in both nematode groups have been recruited from bacteria. The nuclear and mitochondrial genomes of these two nematode groups are very different and we consider how these findings relate to the biology of the organisms. BioEssays 30:249–259, 2008. © 2008 Wiley Periodicals, Inc.

Braendle, Christian. 63 Pheromones: Evolving Language of Chemical Communication in Nematodes //CURRENT BIOLOGY Volume: 22 Issue: 9 Pages: R294-R296 DOI: 10.1016/j.cub.2012.03.035 MAY 8 2012

New research reveals how the intricate repertoire of ascarosides - small molecules acting as multifaceted pheromones in the nematode worm Caenorhabditis elegans - has evolved in divergent nematode taxa occupying contrasted ecological niches.

Bukovinszky, T.; Bakker, E. S.; Raaijmakers, C. E.; et al.. Host location success of root-feeding nematodes in patches that differ in size and quality: A belowground release-recapture experiment //BASIC AND APPLIED ECOLOGY Volume: 13 Issue: 3 Pages: 221-231 2012

Resource patch size and patch nutritional quality are both important factors influencing local densities of herbivores. The responses of herbivores to resource patch size have been mostly studied in aboveground plant-insect interactions, whereas belowground organisms have received little attention. We studied responses of different root-feeding nematode species associated with marram grass (Ammophila arenaria (L.) Link) to resource patch size and quality. Different nematode species were released in experimental mesocosms filled with dune sand in which we established marram grass patches of varying sizes. Half of the patches of small, medium and large size were fertilized to test if immigration probabilities of nematodes depended on patch quality. We tested the hypotheses that (1) nematodes should aggregate on larger patches and (2) colonization of patches would also depend on patch nutritional quality, with higher nematode recapture rates expected in fertilized patches. Two species (Helicotylenchus pseudorobustus, Hemicycliophora thornei) of the five released species were recaptured in the experiment. The fraction of nematodes immigrating into the rhizosphere of a plant patch increased with patch size (i.e. root biomass), which was in line with predictions of the Resource Concentration Hypothesis. When fractions were recalculated to represent recapture rates per liter of soil, recapture rates of nematodes did not differ among patch sizes, indicating that the increase in recapture rates was directly proportional to the increase in patch size. This suggests that the process through which nematodes located patches was not distinguishable from a random process where entering patches is based on random encounters with patch boundaries. In contrast to our expectation, fertilization had a strong negative effect on patch responses of both nematode species. Our study represents an approach that may be used to explore whether belowground biota behave in similar ways as aboveground biota, in order to determine how perceived differences in environments affect ecological interactions.

Bulgheresi, S; Schabussova, I; Chen, T; et al.A new C-type lectin similar to the human immunoreceptor DC-SIGN mediates symbiont acquisition by a marine nematode //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 72 Issue: 4 Pages: 2950-2956 APR 2006

Although thiotrophic symbioses have been intensively studied for the last three decades, nothing is known about the molecular mechanisms of symbiont acquisition. We used the symbiosis between the marine nematode Laxus oneistus and sulfur-oxidizing bacteria to study this process. In this association a monolayer of symbionts covers the whole cuticle of the nematode, except its anterior-most region. Here, we identify a novel Ca(2+) center dot dependent mannose-specific lectin that was exclusively secreted onto the posterior, bacterium-associated region of L. oneistus cuticle. A recombinant form of this lectin induced symbiont aggregation in seawater and was able to compete with the native lectin for symbiont binding in vivo. Surprisingly, the carbohydrate recognition domain of this mannose-binding protein was similar both structurally and functionally to a human dendritic cell-specific immunoreceptor. Our results provide a molecular link between bacterial symbionts and host-secreted mucus in a marine symbiosis and suggest conservation in the mechanisms of host-microbe interactions throughout the animal kingdom.

Choe, Andrea; von Reuss, Stephan H.; Kogan, Dima; et al.Ascaroside Signaling Is Widely Conserved among Nematodes //CURRENT BIOLOGY Volume: 22 Issue: 9 Pages: 772 MAY 8 2012

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 nematode species, we performed a mass spectrometry-based screen for ascarosides in secretions from a variety of both free-living and parasitic (plant, insect, and animal) nematodes. We found that most of the species analyzed, including nematodes from several different clades, produce species-specific ascaroside mixtures. In some cases, ascaroside biosynthesis patterns appear to correlate with phylogeny, whereas in other cases, biosynthesis seems to correlate with lifestyle and ecological niche. We further show that ascarosides mediate distinct nematode behaviors, such as retention, avoidance, and long-range attraction, and that different nematode species respond to distinct, but overlapping, sets of ascarosides. Conclusions: Our findings indicate that nematodes utilize a conserved family of signaling molecules despite having evolved to occupy diverse ecologies. Their structural features and level of conservation are evocative of bacterial quorum sensing, where acyl homoserine lactones (AHLs) are both produced and sensed by many species of gram-negative bacteria. The identification of species-specific ascaroside profiles may enable pheromone-based approaches to interfere with reproduction and survival of parasitic nematodes, which are responsible for significant agricultural losses and many human diseases worldwide.

Ciche, Todd A.; Kim, Kwi-suk; Kaufmann-Daszczuk, Bettina; et al.Cell invasion and matricide during Photorhabdus luminescens transmission by Heterorhabditis bacteriophora nematodes //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 74 Issue: 8 Pages: 2275-2287 APR 2008

Many animals and plants have symbiotic relationships with beneficial bacteria. Experimentally tractable models are necessary to understand the processes involved in the selective transmission of symbiotic bacteria. One such model is the transmission of the insect-pathogenic bacterial symbionts Photorhabdus spp. by Heterorhabditis bacteriophora infective juvenile (IJ)-stage nematodes. By observing egg-laying behavior and IJ development, it was determined that IJs develop exclusively via intrauterine hatching and matricide (i.e., endotokia matricida). By transiently exposing nematodes to fluorescently labeled symbionts, it was determined that symbionts infect the maternal intestine as a biofilm and then invade and breach the rectal gland epithelium, becoming available to the IJ offspring developing in the pseudocoelom. Cell- and stage-specific infection occurs again in the pre-IJ pharyngeal intestinal valve cells, which helps symbionts to persist as Us develop and move to a new host. Synchronous with nematode development are changes in symbiont and host behavior (e.g., adherence versus invasion). Thus, Photorhabdus symbionts are maternally transmitted by an elaborate infectious process involving multiple selective steps in order to achieve symbiont-specific transmission.

Clegg, Roger A.; Bowen, Laura C.; Bicknell, Annalise V.; et al. Characterisation of the N ' 1 isoform of the cyclic AMP-dependent protein kinase (PK-A) catalytic subunit in the nematode, Caenorhabditis elegans //ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS Volume: 519 Issue: 1 Pages: 38-4 MAR 1 2012

Multiple isoforms of the cyclic AMP-dependent protein kinase (PK-A) catalytic (C) subunit, arise as a consequence of the use of lternative splicing strategies during transcription of the kin-1 gene in the nematode. Caenorhabditis elegans. N-myristoylation is a common co-translational modification of mammalian PK-A C-subunits; however, the major isoform (N'3), originally characterised in C. elegans, is not N-myristoylated. Here, we show that N'1 isoforms are targets for N-myristoylation in C elegans. We have demonstrated the in vivo incorporation of radioactivity into N'1 C-subunit isoforms, following incubation of nematodes with [H-3]-myristic acid. HPLC and MALDI-TOF MS analysis of proteolytic digests of immuno-precipitates confirmed the presence of myristoyl-glycine in the C-subunit. In order to better understand the impact of the N'1 N-terminal sequence, and its myristoylation, on C-subunit activity, a chimerical C-subunit, consisting of the N'1 N-terminus from C. elegans and a murine core and C-terminal sequence was expressed. Myristoylation had no appreciable effect on the catalytic properties of the chimeric protein. However, the myristoylated chimeric protein did exhibit enhanced apolar targeting compared to the myristoylated wild-type murine polypeptide. This behaviour may reflect the inability of the N'1-encoded N-terminus sequence to correctly dock with a hydrophobic domain on the surface of the C-subunit. (C) 2012 Elsevier Inc. All rights reserved.

Colgrave, Michelle L.; Kotze, Andrew C.; Huang, Yen-Hua; et al.Cyclotides: Natural, circular plant peptides that possess significant activity against gastrointestinal nematode parasites of sheep//BIOCHEMISTRY Volume: 47 Issue: 20 Pages: 5581-5589 MAY 20 2008

The cyclotides are a novel family of backbone-cyclized eystine-knot containing peptides from plants that have been shown to possess insecticidal activity against Helicoverpa larvae, an important pest of corn and cotton. In the current study, we investigated the in vitro effects of the cyclotides on the viability of egg, larval, and adult life stages of two species of economically important gastrointestinal nematode parasites of livestock, Hemonchus contortus and Trichostrongylus colubriformis. The cyclotides showed significant activity in inhibiting development of nematode larvae and motility of adult worms. Activities were comparable to some currently used anthelmintic compounds in these in vitro assay systems. A series of alanine mutants of the prototypic cyclotide kalata B I were assayed against larvae to determine regions of the peptide responsible for activity. It was observed that anthelmintic activity was dramatically reduced as a consequence of the mutation of a large number of residues that are found clustered on one surface. Activities toward larvae were equivalent in the naturally occurring L-isomer of kalata B1 and a synthetic all-D-isomer, indicating that there is no chiral requirement for anthelmintic activity. The clustering of important residues and the lack of chiral selectivity further support the proposed mode of action of the cyclotides, which involves a membrane-based interaction rather than an interaction at a specific receptor. The cyclotide-induced leakage of a fluorescent dye from vesicles used as a model membrane mimetic further confirms the membrane lytic ability of cyclotides. The relative potency of kalata B I and kalata 132 in causing membrane leakage is consistent with the order of their anthelmintic activity. These results demonstrate that the cyclotides show potential for use in the control of gastrointestinal nematode parasites.

Deaton, Raelynn. Effects of a parasitic nematode on male mate choice in a livebearing fish with a coercive mating system (western mosquitofish, Gambusia affinis) //BEHAVIOURAL PROCESSES Volume: 80 Issue: 1 Pages: 1-6 JAN 2009

I examined the effects of the parasitic larval nematode, Eustrongylides ignotus, on male mate choice in the western mosquitofish, Gambusia affinis. I hypothesized that parasite presence influences male mate choice either directly (via reduction in male mating behavior due to presence of parasite in females) or indirectly (via reduction in male mating behavior due to reduced condition of infected females). Specifically, I tested the predictions that (1) males would mate preferentially with uninfected over infected females (scoring both mating attempts and association time with females); (2) parasitized females would be in poorer condition than non-parasitized females (measured as soluble fat stores); and (3) parasitized females would have reduced fecundity (measured as number of developing embryos). Males preferred to mate with non-parasitized over parasitized females, but showed no differences in association time between females. The nematode did not decrease female body condition, but did decrease female mass, and appeared to decrease female fecundity via reduction in broods (# embryos). Results support that parasites affect male mate choice in mosquitofish; however, the mechanisms used by males to differentiate between parasitized and non-parasitized females remain untested. This study provides the first empirical evidence of parasite affects on male mate choice in livebearing fishes, and suggest a potentially important role for parasite-mediated sexual selection in organisms that use coercive mating as the primary mechanism of obtaining mates.

del Mar Alguacil, Maria; Torrecillas, Emma; Lozano, Zenaida; Evidence of Differences between the Communities of Arbuscular Mycorrhizal Fungi Colonizing Galls and Roots of Prunus persica Infected by the Root-Knot Nematode Meloidogyne incognita//APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 77 Issue: 24 Pages: 8656-8661 DEC 2011

Arbuscular mycorrhizal fungi (AMF) play important roles as plant protection agents, reducing or suppressing nematode colonization. However, it has never been investigated whether the galls produced in roots by nematode infection are colonized by AMF. This study tested whether galls produced by Meloidogyne incognita infection in Prunus persica roots are colonized by AMF. We also determined the changes in AMF composition and biodiversity mediated by infection with this root-knot nematode. DNA from galls and roots of plants infected by M. incognita and from roots of noninfected plants was extracted, amplified, cloned, and sequenced using AMF-specific primers. Phylogenetic analysis using the small-subunit (SSU) ribosomal DNA (rDNA) data set revealed 22 different AMF sequence types (17 Glomus sequence types, 3 Paraglomus sequence types, 1 Scutellospora sequence type, and 1 Acaulospora sequence type). The highest AMF diversity was found in uninfected roots, followed by infected roots and galls. This study indicates that the galls produced in P. persica roots due to infection with M. incognita were colonized extensively by a community of AMF, belonging to the families Paraglomeraceae and Glomeraceae, that was different from the community detected in roots. Although the function of the AMF in the galls is still unknown, we hypothesize that they act as protection agents against opportunistic pathogens.

Delawary, Mina; Nakazawa, Takanobu; Tezuka, Tohru; et al.Molecular characterization of a novel RhoGAP, RRC-1 of the nematode Caenorhabditis elegans //: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Volume: 357 Issue: 2 Pages: 377-382 JUN 1 2007

The GTPase-activating proteins for Rho family GTPases (RhoGAP) transduce diverse intracellular signals by negatively regulating Rho family GTPase-mediated pathways. In this study, we have cloned and characterized a novel RhoGAP for Rac1 and Cdc42, termed RRC-1, from Caenorhabditis elegans. RRC-1 was highly homologous to mammalian p250GAP and promoted GTP hydrolysis of Rac1 and Cdc42 in cells. The rrc-1 mRNA was expressed in all life stages. Using an RRC-1::GFP fusion protein, we found that RRC-1 was localized to the coelomocytes, excretory cell, GLR cells, and uterine-seam cell in adult worms. These data contribute toward understanding the roles of Rho family GTPases in C elegans.

Deng, Li; He, Qingfeng; Kang, Tao; et al.. Identification of an anticoagulant peptide that inhibits both fXIa and fVIIa/tissue factor from the blood-feeding nematode Ancylostoma caninum //BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Volume: 392 Issue: 2 Pages: 155-159 FEB 5 2010

Factor VIIa-tissue factor complex (fVIIa/TF) and factor XIa (fXIa) play important roles in the initiation and amplification of coagulation, respectively. They may be good targets fur the development of novel anticoagulants to treat and prevent thromboembolic disease. In this Study, we cloned, expressed and identified a novel anticoagulant peptide, AcaNAP10, front the blood-feeding nematode Ancylostoma caninum. AcaNAP10 showed potent anticoagulant activity and doubled the activated partial thromboplastin and prothrombin times at estimated concentrations of 92.9 nM and 28.8 nM, respectively. AcaNAP10 demonstrated distinct mechanisms of action compared with known anticoagulants. It inhibited fXIa and fVIIa/TF with IC(50) values of 25.76 +/- 1.06 nM and 123.9 +/- 1.71 nM, respectively. This is the first report on an anticoagulant that can inhibit both fXIa and fVIIa/TF. This anticoagulant peptide may be an alternative molecule for the development of novel anticoagulants. (C) 2010 Elsevier Inc. All rights reserved

Dennehy, JJ; Friedenberg, NA; Yang, YW; et al.Bacteriophage migration via nematode vectors: Host-parasite-consumer interactions in laboratory microcosms //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 72 Issue: 3 Pages: 1974-1979 MAR 2006

Pathogens vectored by nematodes pose serious agricultural, economic, and health threats; however, little is known of the ecological and evolutionary aspects of pathogen transmission by nematodes. Here we describe a novel model system with two trophic levels, bacteriophages and nematodes, each of which competes for bacteria. We demonstrate for the first time that nematodes are capable of transmitting phages between spatially distinct patches of bacteria. This model system has considerable advantages, including the ease of maintenance and manipulation at the laboratory bench, the ability to observe many generations in short periods, and the capacity to freeze evolved strains for later comparison to their ancestors. More generally, experimental studies of complex multispecies interactions, host-pathogen coevolution, disease dynamics, and the evolution of virulence may benefit from this model system because current models (e.g., chickens, mosquitoes, and malaria parasites) are costly to maintain, are difficult to manipulate, and require considerable space. Our initial explorations centered on independently assessing the impacts of nematode, bacterium, and phage population densities on virus migration between host patches. Our results indicated that virus transmission increases with worm density and host bacterial abundance; however, transmission decreases with initial phage abundance, perhaps because viruses eliminate available hosts before migration can occur. We discuss the microbial growth dynamics that underlie these results, suggest mechanistic explanations for nematode transmission of phages, and propose intriguing possibilities for future research.

Dillman, Adler R.; Sternberg, Paul W. Entomopathogenic nematodes //CURRENT BIOLOGY Volume: 22 Issue: 11 Pages: R430-R431 JUN 5 2012

Dillon, Aoife B.; Foster, Aileen; Williams, Christopher D.; et al.Environmental safety of entomopathogenic nematodes - Effects on abundance, diversity and community structure of non-target beetles in a forest ecosystem //BIOLOGICAL CONTROL Volume: 63 Issue: 2 Pages: 107-114 NOV 2012

The large pine weevil, Hylobius abietis, is a serious threat to reforestation in Europe that necessitates routine use of chemical insecticides. Application of entomopathogenic nematodes (EPN) to the coniferous tree stumps in which weevils breed has the potential to reduce the use of chemical pesticides. During field trials to assess the efficacy of nematodes against pine weevil, non-target beetles were also identified and quantified on 10 sites (14 trials). Nematodes were applied to stumps between June and July. Emergence traps captured beetles exiting from nematode-treated and untreated control stumps. Four trials were monitored in the months immediately following nematode application and ten were monitored the year after nematode application. A total of 65 species of non-target beetles were recovered, including 11 saproxylic species. We found no evidence of an effect of applied EPN on non-target beetle species richness, abundance, species richness per individual collected, or Shannon's entropy (H') either immediately or a year after nematode application, when more wood-specialists were recorded. As expected, there were marked differences between sites and/or tree species in the populations of non-target beetles recovered. These results indicate that when EPN are applied in a forest ecosystem to suppress H. abietis populations, the risk to non-target coleopteran populations must be considered negligible.

Dobson, R. J.; Hosking, B. C.; Besier, R. B.; et al.Minimising the development of anthelmintic resistance, and optimising the use of the novel anthelmintic monepantel, for the sustainable control of nematode parasites in Australian sheep grazing systems //AUSTRALIAN VETERINARY JOURNAL Volume: 89 Issue: 5 Pages: 160-166 MAY 2011

Objective To compare the risk of different treatment scenarios on selecting for anthelmintic resistance on Australian sheep farms. Design A computer simulation model predicted populations of Trichostrongylus colubriformis, Haemonchus contortus or Teladorsagia (Ostertagia) circumcincta, and the frequency of anthelmintic resistance genes. Method Nematode populations and the progression of drug resistance for a variety of treatment options and management practices in sheep-rearing areas of Western Australia (WA), Victoria (VIC) and New South Wales (NSW) were simulated. A scoring system was devised to measure the success of each option in delaying resistance to each anthelmintic and in controlling nematode populations. Results The best option at all sites was combining the new anthelmintic (monepantel) with a triple mixture of benzimidazole, levamisole and abamectin (COM). The next best option was: in NSW, rotation at each treatment between monepantel, moxidectin and COM; in VIC, rotation at each treatment between monepantel and COM; and in WA, rotation at each treatment between monepantel (used in winter) and COM or moxidectin (used in summer-autumn). In WA, rapid selection for resistance occurred as a consequence of summer-autumn treatments; however, if a small percentage of adult stock were left untreated then this selection could be greatly reduced. Despite purposely assuming relatively high resistance to benzimidazole and levamisole, COM was still effective in controlling worms and delaying resistance. Conclusions Because of cost constraints, it may not be feasible or profitable for producers to always use the combination of all drugs. However, the second-and third-best options still considerably slowed the development of anthelmintic resistance.

Donskow-Lysoniewska, Katarzyna; Krawczak, Katarzyna; Doligalska, Maria. Heligmosomoides polygyrus: EAE remission is correlated with different systemic cytokine profiles provoked by L4 and adult nematodes //EXPERIMENTAL PARASITOLOGY Volume: 132 Issue: 2 Pages: 243-248 OCT 2012

Primary exposure of mice to gastrointestinal nematode infection with Heligmosomoides polygyrus reduces inflammation in an experimental model of multiple sclerosis. In this study, we aimed to evaluate the ability of H. polygyrus L4 larvae and adults infection to reduce the symptoms of ongoing experimental autoimmune encephalomyelitis (EAE) in female C57Bl/6 mice. EAE was induced by myelin oligodendrocyte glycoprotein MOG(p35-55) and after 21 days mice were orally infected with 200 infective larvae (L3) of H. polygyrus. Reduction in EAE symptoms was observed from 2 days post infection and the symptoms were almost completely inhibited at 6 days post infection. This effect was associated with limited total protein content in the cerebrospinal fluid; CSF, and significant decreased pro-inflammatory IL-12p40 concentration and increased concentration of the regulatory cytokines IL-10, TGF-beta and IL-6 in the CSF and in the serum. The reduction of EAE symptoms in the enteral phase was associated with higher IL-12p40 concentration in the CSF and very low concentrations of IL-17A and IL-2 in the serum. The fourth stage of gastrointestinal nematode can reverse systemic inflammation in animal models of multiple sclerosis by reducing IL-12 and promoting regulatory cytokines production. The mechanism induced by adult nematodes which sustained EAE inhibition can be provoked by regulatory mechanism connected with reduce IL-17A concentration.

Drace, Kevin; Darby, Creg, The hmsHFRS operon of Xenorhabdus nematophila is required for biofilm attachment to Caenorhabditis elegans//APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 74 Issue: 14 Pages: 4509-4515 10JUL 2008

The bacterium Xenorhabdus nematophila is an insect pathogen and an obligate symbiont of the nematode Steinernema carpocapsae. X. nematophila makes a biofilm that adheres to the head of the model nematode Caenorhabditis elegans, a capability X. nematophila shares with the biofilms made by Yersinia pestis and Yersinia pseudotuberculosis. As in Yersinia spp., the X nematophila biofilm requires a 4-gene operon, hmsHFRS. Also like its Yersinia counterparts, the X. nematophila biofilm is bound by the lectin wheat germ agglutinin, suggesting that P-linked N-acetyl-D-glucosamine or N-acetylneuraminic acid is a component of the extracellular matrix. C elegans mutants with aberrant surfaces that do not permit Yersinia biofilm attachment also are resistant to X nematophila biofilms. An X nematophila hmsH mutant that failed to make biofilms on C elegans had no detectable defect in symbiotic association with S. carpocapsae, nor was virulence reduced against the insect Manduca sexta.

Ebssa, Lemma; Fuzy, Eugene M.; Bickerton, Matthew W.; et al.Host density effects on efficacy of entomopathogenic nematodes against white grub (Coleoptera: Scarabaeidae) species //BIOCONTROL SCIENCE AND TECHNOLOGY Volume: 22 Issue: 1 Pages: 117-123 2012

We tested the effect of host density on entomopathogenic nematode efficacy in 1-L pots with grass and soil. In four experiments, combinations ranged from somewhat resistant hosts (oriental beetle, Anomala orientalis, or northern masked chafer, Cyclocephala borealis, with Heterorhabditis bacteriophora) over more susceptible hosts (Japanese beetle, Popillia japonica, with Steinernema glaseri) to a highly susceptible host (P. japonica and S. scarabaei). In each experiment, four larval densities were exposed to two nematode rates over a 14-day period. A significant effect of host density on nematode efficacy occurred only in the A. orientalis-H. bacteriophora combination, but there was no clear trend in the data. This suggests that an exhaustion of available nematode populations to less lethal levels by high host numbers was counteracted by other factors such as increased chances for nematode-host contact and increased host susceptibility due to stress via reduced food resources and increased aggression between larvae.

Finnie, J. W.Review of corynetoxins poisoning of livestock, a neurological disorder produced by a nematode-bacterium complex //AUSTRALIAN VETERINARY JOURNAL Volume: 84 Issue: 8 Pages: 271-277 2006

Foltan, P.; Puza, V.To complete their life cycle, pathogenic nematode-bacteria complexes deter scavengers from feeding on their host cadaver //BEHAVIOURAL PROCESSES Volume: 80 Issue: 1 Pages: 76-79 JAN 2009

The life cycle of commercially used molluscicidal rhabditid nematodes Phasmarhabditis hermaphrodita and entomopathogenic steinernematid nematodes is similar: infective stages carry symbiotic bacteria, which kill their host. Nematodes complete their life cycle feeding on the proliferating symbiont and the host tissue. After 1-2 weeks, new infective stages carrying the bacteria leave the host cadaver in search of new hosts. The removal of invertebrate cadavers by scavengers is extremely fast and represents a severe threat to the developing nematodes. Two-choice trials were used to assess prey choice of the generalist predator/scavenger Pterostichus melanarius (Coleoptera: Carabidae) between Deroceras reticulatum (Mollusca: Agriolimacidae) slugs or wax moth Galleria mellonella (Lepidoptera: Pyralidae) larvae killed by infection of P. hermaphrodita/Steinernema affine and control killed by freezing. We demonstrate that the presence of either of the two nematodes tested deters the beetles from consuming infected cadavers. As P. hermaprodita cannot infect an insect host, we hypothesise the deterrent effect being an evolutionary adaptation of the nematode/bacteria complex rather than the ability of the beetles to avoid potentially infective cadavers.

Foster, Jeremy; Slatko, Barton; Bandi, Claudio; Recombination in Wolbachia Endosymbionts of Filarial Nematodes? // APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 77 Issue: 5 Pages: 1921-1922 MAR 2011

Gibbs, DS; Anderson, GL; Beuchat, LR; et al.. Potential role of Diploscapter sp strain LKC25, a bacterivorous nematode from soil, as a vector of food-borne pathogenic bacteria to preharvest fruits and vegetables //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 71 Issue: 5 Pages: 2433-2437 MAY 2005

Diploscapter, a thermotolerant, free-living soil bacterial-feeding nematode commonly found in compost, sewage, and agricultural soil in the United States, was studied to determine its potential role as a vehicle of Salmonella enterica serotype Poona, enterohemorrhagic Escherichia coli O157:H7, and Listeria monocytogenes in contaminating preharvest fruits and vegetables. The ability of Diploscapter sp. strain LKC25 to survive on agar media, in cow manure, and in composted turkey manure and to be attracted to, ingest, and disperse food-borne pathogens inoculated into soil or a mixture of soil and composted turkey manure was investigated. Diploscapter sp. strain LKC25 survived and reproduced in lawns of S. enterica serotype Poona, E. coli O157:H7, and L. monocytogenes on agar media and in cow manure and composted turkey manure. Attraction of Diploscapter sp. strain LKC25 to colonies of pathogenic bacteria on tryptic soy agar within 10, 20, 30, and 60 min and 24 h was determined. At least 85% of the worms initially placed 0.5 to 1 cm away from bacterial colonies migrated to the colonies within 1 h. Within 24 h, >= 90% of the worms were embedded in colonies. The potential of Diploscapter sp. strain LKC25 to shed pathogenic bacteria after exposure to bacteria inoculated into soil or a mixture of soil and composted turkey manure was investigated. Results indicate that Diploscapter sp. strain LKC25 can shed pathogenic bacteria after exposure to pathogens in these milieus. They also demonstrate its potential to serve as a vector of food-borne pathogenic bacteria in soil, with or without amendment with compost, to the surface of preharvest fruits and vegetables in contact with soil.

Gutternigg, Martin; Kretschmer-Lubich, Dorothea; Paschinger, Katharina; et al.Biosynthesis of truncated N-linked oligosaccharides results from non-orthologous hexosaminidase-mediated mechanisms in nematodes, plants, and insects //JOURNAL OF BIOLOGICAL CHEMISTRY Volume: 282 Issue: 38 Pages: 27825-27840 SEP 21 2007

In many invertebrates and plants, the N-glycosylation profile is dominated by truncated paucimannosidic N-glycans, i.e. glycans consisting of a simple trimannosylchitobiosyl core often modified by core fucose residues. Even though they lack antennal N-acetylglucosamine residues, the biosynthesis of these glycans requires the sequential action of GlcNAc transferase I, Golgi mannosidase II, and, finally, beta-N-acetylglucosaminidases. In Drosophila, the recently characterized enzyme encoded by the fused lobes (fdl) gene specifically removes the non-reducing N-acetylglucosamine residue from the alpha 1,3-antenna of N-glycans. In the present study, we examined the products of five beta-N-acetylhexosaminidase genes from Caenorhabditis elegans (hex-1 to hex-5, corresponding to reading frames T14F9.3, C14C11.3, Y39A1C.4, Y51F10.5, and Y70D2A.2) in addition to three from Arabidopsis thaliana (AtHEX1, AtHEX2, and AtHEX3, corresponding to reading frames At1g65590, At3g55260, and At1g05590). Based on homology, the Caenorhabditis HEX-1 and all three Arabidopsis enzymes are members of the same sub-family as the aforementioned Drosophila fused lobes enzyme but either act as chitotriosidases or non-specifically remove N-acetylglucosamine from both N-glycan antennae. The other four Caenorhabditis enzymes are members of a distinct sub-family; nevertheless, two of these enzymes displayed the same alpha 1,3-antennal specificity as the fused lobes enzyme. Furthermore, a deletion of part of the Caenorhabditis hex-2 gene drastically reduces the native N-glycan-specific hexosaminidase activity in mutant worm extracts and results in a shift in the N-glycan profile, which is a demonstration of its in vivo enzymatic relevance. Based on these data, it is hypothesized that the genetic origin of pauci-mannosidic glycans in nematodes, plants, and insects involves highly divergent members of the same hexosaminidase gene family.

Hohberg, Karin; Traunspurger, Walter. Foraging theory and partial consumption in a tardigrade-nematode system //BEHAVIORAL ECOLOGY Volume: 20 Issue: 4 Pages: 884-890 JUL-AUG 2009

We investigated foraging behavior of a carnivorous eutardigrade, Macrobiotus richtersi, living in soil or fresh water sediments, where the distribution of nematode prey is heterogeneous and where, consequently, the value of information about prey availability should be high. We directly observed diet choice in various mixtures of 2 size classes of nematodes Acrobeloides nanus, A1 (small prey) and A2 (large prey), differing in profitability (biomass divided by handling time) but not in digestive quality. At various prey densities of A2, we measured how much of each prey item was consumed as a function of search time. Additionally, we derived cumulative biomass uptake rates per single A2 prey from 154 complete feeding acts, and we used the marginal value theorem (MVT) to predict optimal residence time and prey exploitation as a function of environmental quality and search time. Macrobiotus richtersi did not preferentially select the more profitable size class A2 but increased its biomass uptake rate by modifying the amount consumed per prey item (partial consumption): when encounter rates were high and there were more high-quality prey, the tardigrade abandoned food more quickly and consumed less biomass per captured prey. We conclude that 1) hungry tardigrades under food-rich or food-limited conditions maximize biomass gain according to MVT and 2) tardigrades differentiate at least 2 prey situations, high supply (at high encounter rates) and low supply (at moderate and low prey densities). 3) Partial consumption, performed under food-rich conditions or by a satiated predator, leads to a reduction of prey numbers up to 3 times as much as under food-poor conditions.

Hosking, B. C.; Griffiths, T. M.; Woodgate, R. G.; et al.Clinical field study to evaluate the efficacy and safety of the amino-acetonitrile derivative, monepantel, compared with registered anthelmintics against gastrointestinal nematodes of sheep in Australia //AUSTRALIAN VETERINARY JOURNAL Volume: 87 Issue: 11 Pages: 455-462 NOV 2009

Objective To determine the efficacy of monepantel, a developmental compound from the amino-acetonitrile derivative class of anthelmintics, against field infections of gastrointestinal nematodes in sheep. Procedures Comparisons of efficacy (using standard faecal worm egg count reduction tests) and safety (on the basis of visual observations) were made in a large-scale field study in Australia, between groups of sheep treated with either an oral solution of monepantel or a registered anthelmintic. The sheep were naturally infected with the major gastrointestinal nematode genera present in Australia. Results The post-treatment efficacy results for monepantel were: at 7 days (+/- 1 day) efficacy was >98%; at 14 days (+/- 1 day) it was generally close to or >99%; and at 21 days (+/- 1 day) efficacy was consistently >99%. A high proportion of the targeted nematode populations were confirmed as being resistant to one or more of the currently available anthelmintic classes. Conclusions Monepantel when used under field conditions at a minimum dose rate of 2.5 mg/kg was highly effective against mixed-genus natural field infections of the major gastrointestinal nematode genera including Haemonchus, Teladorsagia (Ostertagia), Trichostrongylus, Nematodirus, Chabertia and Oesophagostomum. This result included efficacy against some populations resistant to the currently available broad-spectrum anthelmintics. Few Cooperia spp. were present to allow confirmation of efficacy against this genus. On no occasion after treatment did any commercial anthelmintic-treated groups have significantly lower faecal egg counts than the monepantel-treated groups. Monepantel was safe for the target animals and human operators when used in a field situation.

Hsueh, Yen-Ping; Mahanti, Parag; Schroeder, Frank C.; et al.Nematode-Trapping Fungi Eavesdrop on Nematode Pheromones //CURRENT BIOLOGY Volume: 23 Issue: 1 Pages: 83-86 JAN 7 2013

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 [1]. 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 [2-4]. Here, we show that nematophagous fungi, natural predators of soil-dwelling nematodes [5], 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 [6]. 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.

Jarecki, Jessica L.; Andersen, Kari; Konop, Christopher J.; Mapping Neuropeptide Expression by Mass Spectrometry in Single Dissected Identified Neurons from the Dorsal Ganglion of the Nematode Ascaris suum// ACS CHEMICAL NEUROSCIENCE Volume: 1 Issue: 7 Pages: 505-519 JUL 2010

We have developed a method for dissecting single neurons from the nematode Ascaris suum, in order to determine their peptide content by mass spectrometry (MS). In this paper, we use MALDI-TOF MS and tandem MS to enumerate and sequence the peptides present in the two neurons, ALA and RID, that comprise the dorsal ganglion. We compare the peptide content determined by MS with the results of immunocytochemistry and in situ hybridization of previously isolated peptides AF2, AF8, and six peptides encoded by the afp-1 transcript. We find complete agreement among the three techniques, which validates single neuron MS as a method for peptide localization. We also discovered and sequenced six novel peptides in the ALA neuron. Cloning of cDNAs and database searching of Genomic Survey Sequences showed that transcript afp-12 encodes peptide AF36 (VPSAADMMIRFamide) and afp-13 encodes AF19 AEGLSSPLIRFamide), AF34 (DSKLMDPLIRFamide),AF35(DPQQRIVTDETVLRFamide), and three nonamidated peptides (PepTT, PepTL, and PepGE). We have found no similarities with reported peptide expression in the nematode Caenorhabditis elegans. This method promises to be ideally suited for determining the peptide content of each of the 298 neurons in the nervous system of this nematode.

Jeschke, Jonathan M.; Hohberg, Karin.Predicting and testing functional responses: An example from a tardigrade-nematode system // BASIC AND APPLIED ECOLOGY Volume: 9 Issue: 2 Pages: 145-151 2008

Numerous studies have empirically measured consumer functional responses or theoretically developed response models, but whether these models can quantitatively predict observed data has hardly been tested. We perform such a test for the terrestrial predator–prey system Macrobiotus richtersi (Tardigrada)–Acrobeloides nanus (Nematoda). For two different size classes of A. nanus, we report a functional response as measured in the laboratory and quantitatively compare it to predictions of three models with different degrees of complexity: (1) the disc equation which does not include satiation effects; (2) the steady-state satiation (SSS) equation which assumes a constant level of predator satiation; and (3) the satiation model which accounts for prey depletion and increasing predator satiation over the course of the experiments. We parameterized these models with data that were measured independently of the functional response experiments. In both prey-size classes, the predictions of the satiation model matched the observations best, and the match came c ose to that of logistic regressions fitted to the observations. Thus, the parameterized satiation model seems to include the most important determinants of the functional response in our focal system. For understanding functional responses, we need more studies that compare data to independently derived model predictions.

Kennedy, Malcolm W.The polyprotein allergens of nematodes (NPAs) - Structure at last, but still mysterious //EXPERIMENTAL PARASITOLOGY Volume: 129 Issue: 2 Pages: 81-84 OCT 2011

We are engaged in structural and functional studies of several types of lipid binding protein that are only found in nematodes. Amongst these are the nematode polyprotein allergens (NPAs) and we now report the solution structure of ABA-1A (As-NPA-A1), the most repeated unit within the NPA array of Ascaris suum, which is almost identical in amino acid sequence to that of Ascaris lumbricoides. The protein forms a slightly flattened, compact, globular fold consisting of a long central helix that participates in two flanking helical bundles. Two pockets lined with apolar amino acid sidechains are apparent, one in the carboxy-terminal region of the protein, and another smaller one in the amino-terminal region. The former appears to be the main site of fatty acid binding, and the latter may have different, though possibly overlapping, ligand binding propensities. The structure of the binding sites indicates that lipid ligands are anchored within them with their hydrophobic tails oriented towards the core of the protein and their polar headgroups bound to charged sidechains at the mouth of the pockets. The three-dimensional architectures of the amino- and carboxy-terminal halves of ABA-1A are closely similar, thereby strengthening the long-suspected idea that the repeated units of NPAs themselves originate from an ancient duplication event.

Kikuchi, T; Shibuya, H; Jones, JT. Molecular and biochemical characterization of an endo-beta-1,3-glucanase from the pinewood nematode Bursaphelenchus xylophilus acquired by horizontal gene transfer from bacteria //BIOCHEMICAL JOURNAL Volume: 389 Pages: 117-125 JUL 1 2005

We report the cloning and functional characterization of an endo-beta-1,3-glucanase from the pinewood nematode Bursaphelenchus xylophilus acquired by horizontal gene transfer from bacteria. This is the first gene of this type from any nematode species. We show that a similar cDNA is also present in another closely related species B. mucronatus, but that similar sequences are not present in any other nematode studied to date. The B. xylophilus gene is expressed solely in the oesophageal gland cells of the nematode and the protein is present in the nematode's secretions. The deduced amino acid sequence of the gene is very similar to glycosyl hydrolase family 16 proteins. The recombinant protein, expressed in Escherichia coli, preferentially hydrolysed the beta-1,3-glucan laminarin, and had very low levels of activity on beta-1,3-1,4-glucan, lichenan and barley beta-glucan. Laminarin was degraded in an endoglucanase mode by the enzyme. The optimal temperature and pH for activity of the recombinant enzyme were 65 degrees C and pH 4.9. The protein is probably important in allowing the nematodes to feed on fungi. Sequence comparisons suggest that the gene encoding the endo-beta-1,3-glucanase was acquired by horizontal gene transfer from bacteria. B. xylophilus therefore contains genes that have been acquired by this process from both bacteria and fungi. These findings support the idea that multiple independent horizontal gene transfer events have helped in shaping the evolution of several different life strategies in nematodes.

Kulas, Jana; Schmidt, Cosima; Rothe, Michael; et al. Cytochrome P450-dependent metabolism of eicosapentaenoic acid in the nematode Caenorhabditis elegans //: ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS Volume: 472 Issue: 1 Pages: 65-75 APR 2008

The genome of Caenorhabditis elegans contains 75 full length cytochrome P450 (CYP) genes whose individual functions are largely unknown yet. We tested the hypothesis that some of them may be involved in the metabolism of eicosapentaenoic acid (EPA), the predominant polyunsaturated fatty acid of this nematode. Microsomes isolated from adult worms contained spectrally active CYP proteins and showed NADPH-CYP reductase (CPR) activities. They metabolized EPA and with lower activity also arachidonic acid (AA) to specific sets of regioisomeric epoxy- and omega-/(omega-1)-hydroxy-derivatives. 17(R),18(S)-epoxyeicosatetraenoic acid was produced as the main EPA metabolite with an enantiomeric purity of 72%. The epoxygenase and hydroxylase reactions were NADPH-dependent, required the functional expression of the CPR-encoding emb-8 gene, and were inhibited by 17-ODYA and PPOH, two compounds known to inactivate mammalian AA-metabolizing CYP isoforms. Multiple followed by single RNAi gene silencing experiments identified CYP-29A3 and CYP-33E2 as the major isoforms contributing to EPA metabolism in C. elegans. Liquid chromatography/mass spectrometry revealed that regioisomeric epoxy- and hydroxy-derivatives of EPA and AA are endogenous constituents of C. elegans. The endogenous EPA metabolite levels were increased by treating the worms with fenofibrate, which also induced the microsomal epoxygenase and hydroxylase activities. These results demonstrate for the first time that C. elegans shares with mammals the capacity to produce CYP-dependent eicosanoids and may thus facilitate future studies on the mechanisms of action of this important class of signaling molecules.

Lee, Soon Goo; Haakenson, William; McCarter, James P.; et al.Thermodynamic Evaluation of Ligand Binding in the Plant-like Phosphoethanolamine Methyltransferases of the Parasitic Nematode Haemonchus contortus //JOURNAL OF BIOLOGICAL CHEMISTRY Volume: 286 Issue: 44 Pages: 38060-38068 NOV 4 2011

Nematodes are a major cause of disease and the discovery of new pathways not found in hosts is critical for development of therapeutic targets. Previous studies suggest that Caenorhabditis elegans synthesizes phosphocholine via two S-adenosylmethionine (AdoMet)-dependent phosphoethanolamine methyltransferases (PMT). Here we examine two PMT from the parasitic nematode Haemonchus contortus. Sequence analysis suggests that HcPMT1 contains a methyltransferase domain in the N-terminal half of the protein and that HcPMT2 encodes a C-terminal methyltransferase domain, as in the C. elegans proteins. Kinetic analysis demonstrates that HcPMT1 catalyzes the conversion of phosphoethanolamine to phosphomonomethylethanolamine (pMME) and that HcPMT2 methylates pMME to phosphodimethylethanolamine (pDME) and pDME to phosphocholine. The IC50 values for miltefosine, sinefungin, amodiaquine, diphenhydramine, and tacrine suggest differences in the active sites of these two enzymes. To examine the interaction of AdoMet and S-adenosylhomocysteine (AdoCys), isothermal titration calorimetry confirmed the presence of a single binding site in each enzyme. Binding of AdoMet and AdoCys is tight (K-d similar to 2-25 mu M) over a range of temperatures (5-25 degrees C) and NaCl concentrations (0.05-0.5 M). Heat capacity changes for AdoMet and AdoCys binding suggests that each HcPMT differs in interaction surface area. Nonlinear van't Hoff plots also indicate a possible conformational change upon AdoMet/AdoCys binding. Functional analysis of the PMT from a parasitic nematode provides new insights on inhibitor and AdoMet/AdoCys binding to these enzymes.

Luo, Hong; Liu, Yajun; Fang, Lin; et al.Coprinus comatus damages nematode cuticles mechanically with spiny balls and produces potent toxins to immobilize nematodes //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 73 Issue: 12 Pages: 3916-3923 JUN 2007

We reported recently a unique fungal structure, called the spiny ball, on the vegetative hyphae of Coprinus comatus (O. F. Mull.:Fr.) Pers. Although some observations regarding the role of this structure were presented, its function remained largely unknown. In this study, we showed that purified (isolated and washed) spiny balls could immobilize and kill the free-living nematode Panagrellus redivivus Goodey highly efficiently. Scanning electron microscopy studies illustrated that the spiny structure damaged the nematode cuticle, suggesting the presence of a mechanical force during the process of nematode immobilization. Severe injuries on nematode cuticles caused the leakage of inner materials of the nematodes. When these structures were ground in liquid nitrogen, their killing efficacy against nematodes was lost, indicating that the shape and the complete structure of the spiny balls are indispensable for their function. However, extraction with organic solvents never lowered their activity against P. redivivus, and the extracts showed no obvious effect on the nematode. We also investigated whether C comatus was able to produce toxins which would aid in the immobilization of nematodes. In total, we identified seven toxins from C. comatus that showed activity to immobilize the nematodes P. redivivus and Meloidogyne incognita (Kofoid et White) Chitwood. The chemical structures of these toxins were identified with nuclear magnetic resonance, mass spectrometry, infrared, and LTV spectrum analysis. Two compounds were found to be novel. The toxins found in C. comatus are O-containing heterocyclic compounds.

Luong, LT; Kaya, HK. Sexually transmitted nematodes affect spermatophylax production in the cricket, Gryllodes sigillatus //BEHAVIORAL ECOLOGY Volume: 16 Issue: 1 Pages: 153-158 JAN 2005

Parasites can influence various aspects of host reproduction and mating, including spermatophore production. In the cricket, Gryllodes sigillatus, males transfer to females a two-part spermatophore containing a sperm-filled ampulla and a gelatinous spermatophylax (nuptial gift). Here we investigate the effects of a sexually transmitted nematode on male spermatophylax production. Sexually transmitted diseases (STDs) have the potential to reduce host fertility or fecundity in insect hosts. To our knowledge this is the first empirical study on the effects of an insect STD on the reproductive physiology of a male host. Our results indicate that infected males produced significantly smaller spermatophylaces than healthy males; this effect was more apparent for smaller males. Spermatophylax size was inversely correlated with the intensity of infection. Spermatophylax replacement time, the time between producing the first and second spermatophylax, did not differ significantly between infected and healthy males. This parasite-mediated reduction in spermatophylax size may be a direct consequence of the physiological stress of parasitism or parasite manipulation.

Menzel, R; Rodel, M; Kulas, J; et al.. CYP35: Xenobiotically induced gene expression in the nematode Caenorhabditis elegans //ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS Volume: 438 Issue: 1 Pages: 93-102 : JUN 1 2005

Although over 80 cytochrome P450 (CYP) encoding genes have been identified in the genome of the nematode Caenorhabditis elegans very little is known about their involvement in biotransformation. This paper demonstrates a concentration-dependent relationship of C. elegans CYP35A1, A2, A5, and C1 gene expression in response to four organic xenobiotics, namely atrazine, PCB52, fluoranthene, and lansoprazole. The toxicity of these xenobiotics was determined using a reproduction assay. CYP-specific messenger RNA expression was analyzed by semi-quantitative RT-PCR resulting in a strongly increasing, concentration-dependent induction well below the EC50 for reproduction. For PCB52, approximately 0.5% of the EC50 induces a 2-fold increase of CYP35 gene expression. Using a double mutant and multiple RNAi of CYP35A/C it was possible to diminish the reproduction decline caused by PCB52 and fluoranthene.

Miller, Steve. Measuring a nematode with a piezoresistor //ANALYTICAL CHEMISTRY Volume: 80 Issue: 1 Pages: 28-28 Published: JAN 1 2008

Navaneethan, Thurkathipana; Strauch, Olaf; Besse, Samantha; et al.Influence of humidity and a surfactant-polymer-formulation on the control potential of the entomopathogenic nematode Steinernema feltiae against diapausing codling moth larvae (Cydia pomonella L.) (Lepidoptera: Tortricidae) //BIOCONTROL Volume: 55 Issue: 6 Pages: 777-788 DEC 2010

The codling moth (Cydia pomonella L.) is a serious pest of pome fruit. Diapausing cocooned larvae overwinter in cryptic habitats in the soil or in the bark of infested trees. The entomopathogenic nematode Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) is used to control diapausing codling moth larvae. The objective of this study was to define environmental conditions favouring the performance of the nematodes. Cocooned larvae were more susceptible than non-cocooned larvae. Susceptibility of pupae was low. To determine the influence of decreasing water activity (a(w)-value) on the activity of the nematodes, mortality of codling moth larvae and Galleria mellonella L. were tested in sand-sodium-polyacrylate mixtures of variable water activity. S. feltiae was able to infect both insects at a(w)-values >0.9. Cocooned larvae of both insects died at lower a(w)-values than non-cocooned larvae. Mortality of cocooned larvae did not further increase after half an hour of exposure to nematodes, whereas the mortality of non-cocooned larvae increased with increasing exposure time. LC(50) and LC(90) considerably decrease with increasing RH. The negative influence of the relative humidity (macro environment) was less important than the effect of the water activity in the bark substrate (micro environment). The micro environment can be manipulated by applying S. feltiae with higher volumes of water. A surfactant-polymer-formulation significantly increased nematode efficacy and can buffer detrimental environmental effects.

Neidt, Erin M.; Skau, Colleen T.; Kovar, David R.The cytokinesis formins from the nematode worm and fission yeast differentially mediate actin filament assembly//JOURNAL OF BIOLOGICAL CHEMISTRY Volume: 283 Issue: 35 Pages: 23872-23883 AUG 29 2008

Formins drive actin filament assembly for diverse cellular processes including motility, establishing polarity, and cell division. To investigate the mechanism of contractile ring assembly in animal cells, we directly compared the actin assembly properties of formins required for cytokinesis in the nematode worm early embryo (CYK-1) and fission yeast (Cdc12p). Like Cdc12p and most other formins, CYK-1 nucleates actin filament assembly and remains processively associated with the elongating barbed end while facilitating the addition of profilin-actin above the theoretical diffusion-limited rate. However, specific properties differ significantly between Cdc12p and CYK-1. Cdc12p efficiently nucleates filaments that in the presence of profilin elongate at approximately the same rate as control filaments without formin (similar to 10.0 subunits/s). CYK-1 is an inefficient nucleator but allows filaments to elongate profilin-actin 6-fold faster than Cdc12p (similar to 60 subunits/s). Both Cdc12p and CYK-1 bind to pre-assembled actin filaments with low nanomolar affinity, but CYK-1 dissociates 2 orders of magnitude more quickly. However, CYK-1 rapidly re-associates with free barbed ends. Cdc12p allows barbed ends to elongate in the presence of excess capping protein, whereas capping protein inhibits CYK-1-mediated actin assembly. Therefore, these evolutionarily diverse formins can drive contractile ring assembly by a generally similar mechanism, but cells with unique dimensions and physical parameters might require proteins with carefully tuned actin assembly properties.

Noguez, Jaime H.; Conner, Elizabeth S.; Zhou, Yue; A Novel Ascaroside Controls the Parasitic Life Cycle of the Entomopathogenic Nematode Heterorhabditis bacteriophora // ACS CHEMICAL BIOLOGY Volume: 7 Issue: 6 Pages: 961-966 JUN 2012

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 nknown 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. acteriophora, suggesting that there is a high degree of species specificity. Our report is the first to show that scarosides 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.

Ntalli, Nikoletta G.; Caboni, Pierluigi, Botanical nematicides in the mediterranean basin//PHYTOCHEMISTRY REVIEWS Volume: 11 Issue: 4 Special Issue: SI Pages: 351-359 DEC 2013

Achieving food sufficiency in a sustainable manner is a major challenge for farmers, agroindustries,researchers and governments. Amongst agricultural pests supressing crops, root-knot nematodes (Meloidogyne spp.) represent possibly the world’s most damaging one, the control of which has been mainly based on chemical nematicides. In the recent years the environmental, food safety and animal welfare issues pose the need for alternative nematode control measures. Screening naturally occurring compounds in plants, involved in the complex chemicalmediated interactions between a plant and other organisms in its environment, can provide with innovative nematode control measures that can be safely used in integrated pest management programs. The Mediterranean Basin is an area where various soils and climatic conditions allow a vast plant biodiversity providing with chemical botanicals of significant nematicidal potency. This is a review on the Mediterranean botanicals that can control Meloidogyne spp.

Pillai, A; Ueno, S; Zhang, H; et al.. Cecropin P1 and novel nematode cecropins: a bacteria-inducible antimicrobial peptide family in the nematode Ascaris suum //BIOCHEMICAL JOURNAL Volume: 390 Pages: 207-214 Part: 1 AUG 15 2005

Cecropin PI was first identified as a mammalian antimicrobial peptide isolated from the pig intestine. Much research aimed at characterizing this peptide has been reported. Recently, the workers who discovered the peptide corrected their original conclusion, and confirmed that this peptide originates in fact from the pig intestinal parasitic nematode, Ascaris swim. In the present study, we carried out a semi-exhaustive search for bacteria-inducible transcripts in A. suum by the cDNA subtraction method. The transcripts encoding cecropin P1 and novel Ascaris cecropins, designated cecropins P2, P3 and P4, were found to be positively induced factors. Chemically synthesized Ascaris cecropins were bactericidal against a wide range of microbes, i.e. Gram-positive (Staphylococcus aureus, Bacillus subtilis and Micrococcus luteus) and Gram-negative (Pseudomonas aeruginosa, Salmonella typhimurium, Serratia marcescens and Esherichia coli) bacteria, and were weakly but detectably active against yeasts (Saccharomyces cerevisiae and Candida albicans). Cecropin PI-like sequences were also detected at least in two other species (Ascaris lumbri-coides and Toxocara canis) of the Ascarididae. All Ascaris cecropin precursors contain an acidic pro-region connected by a tetrabasic cleavage site at the C-terminus. Such an acidic pro-region is also reported to be present in the tunicate cecropin-type antimicrobial peptide styelin. On the basis of the evolutionary position of nematodes and tunicates, the ancestral cecropin may have contained the acidic pro-region at the C-terminus.

Pun, Pamela Boon Li; Gruber, Jan; Tang, Soon Yew; et al.Ageing in nematodes: do antioxidants extend lifespan in Caenorhabditis elegans? //BIOGERONTOLOGY Volume: 11 Issue: 1 Pages: 17-30 FEB 2010

Antioxidants are often investigated as a promising strategy for extending lifespan. Accordingly, there is significant interest in novel antioxidant compounds derived from natural sources such as plant extracts. However, because lifespan studies are laborious and expensive to conduct, candidate compounds are frequently selected based simply on their in vitro antioxidant efficacy, with the implicit assumption that in vitro antioxidants are also in vivo antioxidants, and that in vivo antioxidants will decrease functionally relevant oxidative damage and thereby extend lifespan. We investigated the validity of these assumptions in the model organism, Caenorhabditis elegans. Nematodes were exposed to 6 plant extracts, selected out of a total of 34 based on a simple in vitro antioxidant assay. We found no correlation between in vitro and in vivo antioxidant capacities. Antioxidant efficacies were also not predictive of lifespan benefits. Further studies into those extracts that produced significant lifespan extension indicated that a direct antioxidant effect is unlikely to be the main factor responsible for the modulation of nematode lifespan.

Raja, Ramalingam Karthik; Sivaramakrishnan, Sivaperumal; Hazir, Selcuk. . Ecological characterisation of Steinernema siamkayai (Rhabditida: Steinernematidae), a warm-adapted entomopathogenic nematode isolate from India //BIOCONTROL Volume: 56 Issue: 5 Pages: 789-798 OCT 2011

Our study describes basic ecological properties of Steinernema siamkayai Tiruchirappalli strain from India. The effect of temperature on nematode infectivity and development, laboratory host range and foraging behaviour were determined. The data showed that S. siamkayai is a warm-adapted nematode species with larval mortality observed between 15A degrees C and 37.5A degrees C and nematode reproduction occurring between 20A degrees C and 35A degrees C. All insect species used in this study were susceptible to S. siamkayai under laboratory conditions. Sixty infective juveniles (IJs) per insect were used and the lepidopterans, Galleria mellonella (100%) and Spodoptera exigua (85%), were the most susceptible species followed by the dipteran, Ceratitis capitata (60%), and lepidopteran, Cydia splendana (55%), and the coleopteran, Tenebrio molitor (45%), whereas the coleopteran, Curculio elephas (25%), was the least susceptible species. S. siamkayai infective juveniles (IJs) stood on their tails and jumped and could also attach to a mobile host at a rate of 27 IJs larvae(-1) out of 1000 IJs in 10 min. Larval mortality of G. mellonella by S. siamkayai on different substrates (sand, filter paper, filter paper sprinkled with sand) was 100% on all substrates. Number of IJs out of 100 IJs that penetrated into a G. mellonella host at different soil depths was the highest at the surface (44 IJs larva(-1)) and the lowest at 5 cm depth (13 IJs larva(-1)) with no larval mortality observed at 10 cm depth. In addition, the symbiotic bacterium of S. siamkayai was identified as Xenorhabdus stockiae based on genotypic and phenotypic characterisation. Bacterial growth was observed between 15A degrees C and 41A degrees C.

Rendell, D. K. Anthelmintic resistance in cattle nematodes on 13 south-west Victorian properties //AUSTRALIAN VETERINARY JOURNAL Volume: 88 Issue: 12 Pages: 504-509 DEC 2010

Objective To report the level of anthelmintic resistance on 13 commercial cattle properties in south-west Victoria, Australia. Procedure Between 2006 and 2009 worm egg count reduction tests were conducted on calves on the 13 properties. Samples were collected 10-14 days post anthelmintic treatment and worm egg counts and larval differentiation tests were conducted. Resistance was defined if there was less than 95% reduction (lower confidence limit <90%) in the faecal worm egg count for the particular genus. Results The percentage of properties with anthelmintic resistance in at least one species was 54% for benzimidazole (BZ), 100% for levamisole (LEV) and for ivermectin (IVM) it was 100% for the half-dose (0.1 mg/kg) and 62% for the full dose (0.2 mg/kg). A substantial frequency of resistance was detected in Ostertagia ostertagi to BZ (5/11), LEV (3/3) and IVM (5/11), in Trichostrongylus spp. to BZ (4/7) and in Cooperia spp. to IVM (6/11). No resistance to LEV was detected in Trichostrongylus or Cooperia spp. Suspected IVM-resistant Trichostrongylus spp. and BZ-resistant Cooperia spp. were only detected on one property each. Conclusion This is the first Australian report of macrocyclic lactone-resistant O. ostertagi in the refereed literature. The frequency of resistance in O. ostertagi to BZ, LEV and IVM and in Trichostrongylus spp. to BZ in the present study appears higher than levels detected in the 2004-05 New Zealand survey, whereas the resistance frequency in Cooperia spp. to IVM and BZ was less.

Richards, Gregory R.; Goodrich-Blair, Heidi, Examination of Xenorhabdus nematophila Lipases in Pathogenic and Mutualistic Host Interactions Reveals a Role for xlpA in Nematode Progeny Production //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 76 Issue: 1 Pages: 221-229 JAN 2010

Xenorhabdus nematophila is a gammaproteobacterium and broad-host-range insect pathogen. It is also a symbiont of Steinernema carpocapsae, the nematode vector that transports the bacterium between insect hosts. X. nematophila produces several secreted enzymes, including hemolysins, lipases, and proteases, which are thought to contribute to virulence or nutrient acquisition for the bacterium and its nematode host in vivo. X. nematophila has two lipase activities with distinct in vitro specificities for Tween and lecithin. The gene encoding the Tween-specific lipase, xlpA, has been identified and is not required for X. nematophila virulence in one insect host, the tobacco hornworm Manduca sexta. However, the gene encoding the lecithin-specific lipase activity is not currently known. Here, we identify X. nematophila estA, a gene encoding a putative lecithinase, and show that an estA mutant lacks in vitro lipase activity against lecithin but has wild-type virulence in Manduca sexta. X. nematophila secondary-form phenotypic variants have higher in vitro lecithinase activity and estA transcript levels than do primary-form variants, and estA transcription is negatively regulated by NilR, a repressor of nematode colonization factors. We establish a role for xlpA, but not estA, in supporting production of nematode progeny during growth in Galleria mellonella insects. Future research is aimed at characterizing the biological roles of estA and xlpA in other insect hosts.

Robinet, Christelle; Van Opstal, Nico; Baker, Richard; et al.Applying a spread model to identify the entry points from which the pine wood nematode, the vector of pine wilt disease, would spread most rapidly across Europe //BIOLOGICAL INVASIONS Volume: 13 Issue: 12 Pages: 2981-2995 DEC 2011

Pine wilt disease, which can rapidly kill pines, is caused by the pine wood nematode, Bursaphelenchus xylophilus. It is expanding its range in many countries in Asia and measures are being taken at the EU level to prevent its spread from Portugal. Due to the threat to European forests, it is important to prevent additional introductions and target surveillance to the points of entry that pose the greatest risk. In this study, we present a model to identify the European ports from which the nematode can spread most rapidly across Europe. This model describes: (1) the potential spread of the pine wood nematode based on short-distance spread (the active flight of the vector beetles) and long-distance spread (primarily due to human-mediated transportation), and (2) the development of pine wilt disease based on climate suitability and the potential spread of the nematode. Separate introductions at 200 European ports were simulated under various climate change scenarios. We found that the pine wood nematode could invade 19-60% of the study area (30 degrees 00 N-72 degrees 00 N, 25 degrees 00 W-40 degrees 00 E) by 2030, with the highest spread from ports located in Eastern and Northern Europe. Based on climate change scenarios, the disease could affect 8-34% of the study area by 2030, with the highest spread from ports located in South-Eastern Europe. This study illustrates how a spread model can be used to determine the critical points of entry for invasive species, so that surveillance can be targeted more accurately and control measures prioritised.

Sakurai, Masayuki; Watanabe, Yoh-ichi; Watanabe, Kinnitsuna; et al.. A protein extension to shorten RNA: elongated elongation factor-Tu recognizes the D-arm of T-armless tRNAs in nematode mitochondria //BIOCHEMICAL JOURNAL Volume: 399 Pages: 249-256 Part 2 OCT 15 2006

Nematode mitochondria possess extremely truncated tRNAs. Of 22 tRNAs, 20 lack the entire T-arm. The T-arm is necessary for the binding of canonical tRNAs and EF (elongation factor)-Tu (thermo-unstable). The nematode mitochondrial translation system employs two different EF-Tu factors named EF-Tu1 and EF-Tu2. Our previous study showed that nematode Caenorhabditis elegans EF-Tu1 binds specifically to T-armless tRNA. C. elegans EF-Tu1 has a 57-amino acid C-terminal extension that is absent from canonical EF-Tu, and the T-arm-binding residues of canonical EF-Tu are not conserved. In this study, the recognition mechanism of T-armless tRNA by EF-Tu1 was investigated. Both modification interference assays and primer extension analysis of cross-linked ternary complexes revealed that EF-Tu1 interacts not only with the tRNA acceptor stem but also with the D-arm. This is the first example of an EF-Tu recogpizing the D-arm of a tRNA. The binding activity of EF-Tu1 was impaired by deletion of only 14 residues from the C-terminus, indicating that the C-terminus of EF-Tu1 is required for its binding to T-armless tRNA. These results suggest that C. elegans EF-Tu1 recognizes the D-arm instead of the T-arm by a mechanism involving its C-terminal region. This study sheds light on the co-evolution of RNA and RNA-binding proteins in nematode mitochondria.

Sarkar, S. Datta; Choudhury, B.Study of Refractive Indices, Density and Order Parameters of Two Nematogens and Their Eutectic Mixture //ACTA PHYSICA POLONICA A Volume: 118 Issue: 4 Pages: 665-669 OCT 2010

The compounds 5-pentyl-2-(4'-cyanophenyl) pyrimidine [CM 7035] and 4-n-butyl-4'-ethoxytolan [PTP4O2] and mixtures of different mole fractions of them show nematic phase with supercooling effect. From the phase diagram the equimolar mixture is found to be the eutectic mixture. Temperature variation of the density and refractive indices (n(o), n(e)) of the pure compounds and their eutectic mixture have been reported here. The density and birefringence values of the eutectic mixture are found to be less than that of pure compounds. However the average refractive index values of eutectic mixture almost coincide with those of CM 7035 which are much less than those of PTP4O2. The refractive indices and density values have been analyzed to obtain the orientational order parameters. Experimental order parameter values of the pure compounds and the eutectic mixture are compared with theoretical Maier-Saupe values. The possible reasons for disagreement between theoretical and experimental values for the pure compounds are discussed. The agreement between theoretical and experimental order parameters are fairly good for the eutectic mixture.

Schmidt, Liesbeth M.; Mouton, Laurence; Nong, Guang; et al.. Genetic and immunological comparison of the cladoceran parasite Pasteuria ramosa with the nematode parasite Pasteuria penetrans //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 74 Issue: 1 Pages: 259-264 2008

Pasteuria penetrans, an obligate endospore-forming parasite of Meloidogyne spp. (root knot nematodes), has been identified as a promising agent for biocontrol of these destructive agricultural crop pests. Pasteuria ramosa, an obligate parasite of water fleas (Daphnia spp.), has been shown to modulate cladoceran populations in natural ecosystems. Selected sporulation genes and an epitope associated with the spore envelope of these related species were compared. The sigE and spoIIAA/spoIIAB genes differentiate the two species to a greater extent than 16S rRNA and may serve as probes to differentiate the species. Single-nucleotide variations were observed in several conserved genes of five distinct populations of P. ramosa, and while most of these variations are silent single-nucleotide polymorphisms, a few result in conservative amino acid substitutions. A monoclonal antibody directed against an adhesin epitope present on P. penetrans P20 endospores, previously determined to be specific for Pasteuria spp. associated with several phytopathogenic nematodes, also detects an epitope associated with P. ramosa endospores. Immunoblotting provided patterns that differentiate P. ramosa from other Pasteuria spp. This monoclonal antibody thus provides a probe with which to detect and discriminate endospores of different Pasteuria spp. The presence of a shared adhesin epitope in two species with such ecologically distant hosts suggests that there is an ancient and ecologically significant recognition process in these endospore-forming bacilli that contributes to the virulence of both species in their respective hosts.

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Selch, Florian; Higashibata, Akira; Imamizo-Sato, Mari; et al.. Genomic response of the nematode Caenorhabditis elegans to spaceflight //ADVANCES IN SPACE RESEARCH Volume: 41 Issue: 5 Pages: 807 2008

Oil Earth, it is common to employ laboratory animals such as the nematode Caenorhabditis elegans to help understand human health concerns. Similar studies in Earth orbit should help understand and address the concerns associated with spaceflight. The "International Caenorhabditis elegans Experiment FIRST" (ICE FIRST), was carried out onboard the Dutch Taxiflight in April of 2004 by all international collaboration of laboratories in France, Canada, Japan and the United States. With the exception of a slight movement defect upon return to Earth, the result of altered muscle development, no significant abnormalities were detected in spaceflown C. elegans. Work from Japan revealed apoptosis proceeds normally and work from Canada revealed no significant increase in the rate of mutation. These results suggest that C elegans call be used to study non-lethal responses to spaceflight and call possibly be developed as a biological sensor. To further our understanding of C elegans response to spaceflight, we examined the gene transcription response to the 10 days in space using a near full genome microarray analysis. The transcriptional response is consistent with the observed normal developmental timing, apoptosis, DNA repair, and altered muscle development. The genes identified as altered in response to spaceflight are enriched for genes known to be regulated, in C elegans, in response to altered environmental conditions (Insulin and TGF-beta regulated). These results demonstrate C elegans call be used to study the effects of altered gravity and suggest that C. elegans responds to spaceflight by altering the expression of at least some of the same metabolic genes that are altered in response to differing terrestrial environments.

Sergeant, Martin; Baxter, Laura; Jarrett, Paul; et al.Identification, typing, and insecticidal activity of Xenorhabdus isolates from entomopathogenic nematodes in United Kingdom soil and characterization of the xpt toxin loci //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 72 Issue: 9 Pages: 5895-5907 SEP 2006

Xenorhabdus strains from entomopathogenic nematodes isolated from United Kingdom soils by using the insect bait entrapment method were characterized by partial sequencing of the 16S rRNA gene, four housekeeping genes (asd, ompR, recA, and serC) and the flagellin gene (fliC). Most strains (191/197) were found to have genes with greatest similarity to those of Xenorhabdus bovienii, and the remaining six strains had genes most similar to those of Xenorhabdus nematophila. Generally, 16S rRNA sequences and the sequence types based on housekeeping genes were in agreement, with a few notable exceptions. Statistical analysis implied that recombination had occurred at the serC locus and that moderate amounts of interallele recombination had also taken place. Surprisingly, the fliC locus contained a highly variable central region, even though insects lack an adaptive immune response, which is thought to drive flagellar variation in pathogens of higher organisms. All the X. nematophila strains exhibited a consistent pattern of insecticidal activity, and all contained the insecticidal toxin genes xptA1A2B1C1, which were present on a pathogenicity island (PAI). The PAIs were similar among the X. nematophila strains, except for partial deletions of a peptide synthetase gene and the presence of insertion sequences. Comparison of the PAI locus with that of X. bovienii suggested that the PAI integrated into the genome first and then acquired the xpt genes. The independent mobility of xpt genes was further supported by the presence of xpt genes in X. bovienii strain 173 on a type 2 transposon structure and by the variable patterns of insecticidal activity in X. bovienii isolates, even among closely related strains.

Shim, Jiwon; Lee, Junho. Regulation of rnt-1 expression mediated by the opposing effects of BRO-1 and DBL-1 in the nematode Caenorhahditis elegans//BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Volume: 367 Issue: 1 Pages: 130-136 FEB 29 2008

During development of Caenorhabditis elegans, expression of the RUNX homolog, rnt-1, is tightly regulated both spatially and temporally. In this study, we investigated the mechanism underlying the temporal regulation of rnt-1. We found that rnt-1 contained evolutionarily conserved consensus RUNX binding sequences within one of its introns, and that RNT-1 bound to these intronic sequences both in vitro and in vivo in the presence of BRO-1, suggesting that RNT-1 together with BRO-1 represses its own transcription. Fine deletion and substitution experiments revealed a binding site within the intron that was critical for rnt-1 regulation. Importantly, we found that the TGF beta homolog, DBL-1, was required for counteracting the repressive activity of BRO-1 at postembryonic stages. Accordingly, ectopic expression of DBL-1 induced transcription of rnt-1 in the lateral hypodermis and other tissues even at the postembryonic stages. Taken together, our data suggest that rnt-1 expression is regulated by the balance between DBL-1-mediated activation and BRO-1-mediated repression at the postembryonic stages. (C) 2007 Elsevier Inc. All rights reserved.

Siddiqui, IA; Haas, D; Heeb, S.Extracellular protease of Pseudomonas fluorescens CHA0, a biocontrol factor with activity against the root-knot nematode Meloidogyne incognita //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 71 Issue: 9 Pages: 5646-5649 SEP 2005

In Pseudomonas fluorescens CHAO, mutation of the GacA-controlled aprA gene (encoding the major extracellular protease) or the gacA regulatory gene resulted in reduced biocontrol activity against the root-knot nematode Meloidogyne incognita during tomato and soybean infection. Culture supernatants of strain CHAO inhibited egg hatching and induced mortality of M. incognita juveniles more strongly than did supernatants of aprA and gacA mutants, suggesting that AprA protease contributes to biocontrol.

Snyder, Holly; He, Hongjun; Owen, Heather; et al.Role of Mrx Fimbriae of Xenorhabdus nematophila in Competitive Colonization of the Nematode Host //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 77 Issue: 20 Pages: 7247-7254 OCT 2011

Xenorhabdus nematophila engages in mutualistic associations with the infective juvenile (IJ) stage of specific entomopathogenic nematodes. Mannose-resistant (Mrx) chaperone-usher-type fimbriae are produced when the bacteria are grown on nutrient broth agar (NB agar). The role of Mrx fimbriae in the colonization of the nematode host has remained unresolved. We show that X. nematophila grown on LB agar produced flagella rather than fimbriae. IJs propagated on X. nematophila grown on LB agar were colonized to the same extent as those propagated on NB agar. Further, progeny IJs were normally colonized by mrx mutant strains that lacked fimbriae both when bacteria were grown on NB agar and when coinjected into the insect host with aposymbiotic nematodes. The mrx strains were not competitively defective for colonization when grown in the presence of wild-type cells on NB agar. In addition, a phenotypic variant strain that lacked fimbriae colonized as well as the wild-type strain. In contrast, the mrx strains displayed a competitive colonization defect in vivo. IJ progeny obtained from insects injected with comixtures of nematodes carrying either the wild-type or the mrx strain were colonized almost exclusively with the wild-type strain. Likewise, when insects were coinjected with aposymbiotic IJs together with a comixture of the wild-type and mrx strains, the resulting IJ progeny were predominantly colonized with the wild-type strain. These results revealed that Mrx fimbriae confer a competitive advantage during colonization in vivo and provide new insights into the role of chaperone-usher fimbriae in the life cycle of X. nematophila.

Snyder, Holly; Stock, S. Patricia; Kim, Sam-Kyu; et al.New insights into the colonization and release processes of Xenorhabdus nematophila and the morphology and ultrastructure of the bacterial receptacle of its nematode host, Steinernema carpocapsae //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 73 Issue: 16 Pages: 5338-5346 AUG 2007

We present results from epifluorescence, differential interference contrast, and transmission electron microscopy showing that Xenorhabdus nematophila colonizes a receptacle in the anterior intestine of the infective juvenile (IJ) stage of Steinernema carpocapsae. This region is connected to the esophagus at the esophagointestinal junction. The process by which X. nematophila leaves this bacterial receptacle had not been analyzed previously. In this study we monitored the movement of green fluorescent protein-labeled bacteria during the release process. Our observations revealed that Xenorhabdus colonizes the distal region of the receptacle and that exposure to insect hemolymph stimulated forward movement of the bacteria to the esophagointestinal junction. Continued exposure to hemolymph caused a narrow passage in the distal receptacle to widen, allowing movement of Xenorhabdus down the intestine and out the anus. Efficient release of both the wild type and a nomnotile strain was evident in most of the IJs incubated in hemolymph, whereas only a few IJs incubated in nutrient-rich broth released bacterial cells. Incubation of IJs in hemolymph treated with agents that induce nematode paralysis dramatically inhibited the release process. These results suggest that bacterial motility is not required for movement out of the distal region of the receptacle and that hemolymph-induced esophageal pumping provides a force for the release of X. nematophila out of the receptacle and into the intestinal lumen.

Srikumar, S., Ethanolamine Utilization Contributes to Proliferation of Salmonella enterica Serovar Typhimurium in Food and in Nematodes //APPLIED AND ENVIRONMENTAL MICROBIOLOGY Volume: 77 Issue: 1 Pages: 281-290 JAN 2011

Only three pathogenic bacterial species, Salmonella enterica, Clostridium perfringens, and Listeria monocytogenes, are able to utilize both ethanolamine and 1,2-propanediol as a sole carbon source. Degradation of these substrates, abundant in food and the gut, depends on cobalamin, which is synthesized de novo only under anaerobic conditions. Although the eut, pdu, and cob-cbi gene clusters comprise 40 kb, the conditions under which they confer a selection advantage on these food-borne pathogens remain largely unknown. Here we used the luciferase reporter system to determine the response of the Salmonella enterica serovar Typhimurium promoters P(eutS), P(pocR), P(pduF), and P(pduA) to a set of carbon sources, to egg yolk, to whole milk, and to milk protein or fat fractions. Depending on the supplements, specific inductions up to 3 orders of magnitude were observed for P(eutS) and P(pduA), which drive the expression of most eut and pdu genes. To correlate these significant expression data with growth properties, nonpolar deletions of pocR, regulating the pdu and cob-cbi genes, and of eutR, involved in eut gene activation, were constructed in S. Typhimurium strain 14028. During exponential growth of the mutants 14028 Delta pocR and 14028 Delta eutR, 2- to 3-fold-reduced proliferation in milk and egg yolk was observed. Using the norhabditis elegans infection model, we could also demonstrate that the liferation of S. Typhimurium in the nematode is supported by an active ethanolamine degradation pathway. Taking these findings together, this study quantifies the differential expression of eut and pdu genes under distinct conditions and provides experimental evidence that the ethanolamine utilization pathway allows salmonellae to occupy specific metabolic niches within food environments and within their host organisms.

Srivastava, Deepti; Arya, Upasna; SoundaraRajan, Thangavelu; et al.. Reserpine can confer stress tolerance and lifespan extension in the nematode C-elegans //BIOGERONTOLOGY Volume: 9 Issue: 5 Pages: 309-316 OCT 2008

Though the lifespan extension mechanism is partly understood from C. elegans to mice, a viable pharmacological intervention is not yet feasible. Here, we report that reserpine largely known as an antipsychotic-antihypertensive drug, can extend C. elegans lifespan. Chronic reserpine treatment from embryo stage or young adults extends the C. elegans lifespan robustly at 25 degrees C. Most importantly, the reserpine treated long lived worms are active (locomotion and pharyngeal pumping) for a long time thereby conferring high quality throughout life. Reserpine mediated lifespan extension is independent of the daf-16 pathway and partly requires serotonin. Reserpine treatment makes the worms highly thermotolerant. Thus, in addition to its known function, reserpine is able to provide stress tolerance and lifespan extension in C. elegans.

Suda, H; Shouyama, T; Yasuda, K; et al.Direct measurement of oxygen consumption rate on the nematode Caenorhabditis elegans by using an optical technique //BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Volume: 330 Issue: 3 Pages: 839-843 MAY 13 2005

It is well known that aging and longevity strongly correlate with energy metabolism. The nematode Caenorhabditis elegans is widely used as an ultimate model of experimental animals. Thus, we developed a novel tool, which is constructed from an optical detector, using an indirect method that can measure simply the energy metabolism of C elegans. If we measure the oxygen consumption rate using this optical tool, we can easily evaluate the activity of mitochondria as an index in the aging process. However, a direct measurement of the oxygen consumption rate of C elegans exposed in air is thought to be impossible because of the high concentration of atmospheric oxygen and the small size of the animals. We demonstrate here that we can directly detect the oxygen consumption with a small number of animals (<= 40) and a short accumulation time (<= 30 min) at high precision by using both an optical probe and a small chamber. The metabolic rate of a 4-day-old hermaphrodite animal, for example, was approximately 80 nW. Our method using C elegans has the potential to become a useful technique for research on aging correlated with energy metabolism.

Swe, Aung; Jeewon, Rajesh; Pointing, Stephen B.; et al.Diversity and abundance of nematode-trapping fungi from decaying litter in terrestrial, freshwater and mangrove habitats //BIODIVERSITY AND CONSERVATION Volume: 18 Issue: 6 Pages: 1695-1714 JUN 2009

Nematode-trapping fungi are ubiquitous in terrestrial habitats in dung, soils, litter and woody debris and they also occur in freshwater, but only one species has been found in marine habitats. The purpose of this study was therefore to investigate whether nematode-trapping fungi occurred in mangrove habitats. To achieve this we assessed the diversity of nematode-trapping fungi on decaying litter from mangroves, freshwater and terrestrial habitats (22 sites) in Hong Kong. Composite samples (n = 1,320) of decaying litter (wood and leaves) were examined and a total of 31 species of nematode-trapping fungi belonging to four genera, Arthrobotrys, Monacrosporium, and Dactylella were recorded. Twenty-nine species reported in this study are new records for Hong Kong and 16 species are new records from mangrove habitats worldwide. Nematode trapping fungi are therefore present in marine environments. Commonly encountered taxa were Arthrobotrys oligospora and Monacrosporium thaumasium which are abundant in all habitats. A. oligospora, M. thaumasium and Arthrobotrys musiformis were frequent (F > 10%). Twenty-six species were rare (0.16-9.32%). Species richness and diversity was higher in terrestrial than in freshwater and mangrove habitats (ANOVA, P < 0.001). A higher mean diversity was observed on decaying leaves as compared to decaying wood in all habitats (P < 0.001). Based on Shannon diversity index, it was also observed that taxa characterized by adhesive nets were more frequent in all habitats. This can be explained by the fact that these taxa may have a better competitive saprotrophic ability which would allow them to compete favourably in nutrient limited environments. Abiotic factors that could be linked to differences in species diversity between decaying wood and leaves are also discussed.

Szabo, Marton; Csepregi, Kitti; Galber, Monika; et al.Control plant-parasitic nematodes with Trichoderma species and nematode-trapping fungi: The role of chi18-5 and chi18-12 genes in nematode egg-parasitism //BIOLOGICAL CONTROL Volume: 63 Issue: 2 Pages: 121-NOV 2012

Eighteen strains of five Trichoderma species (Trichoderma atroviridae. Trichoderma harzianum, Trichoderma rossicum. Trichoderma tomentosum, Trichoderma Wrens) and six strains of four nematode-trapping fungi (Arthrobotrys oligospora. Arthrobotrys tortor, Monacrosporium haptotylum and Monacrosporium cionopagum) were tested in 90 combinations in order to identify the most appropriate partners to control plant-parasitic nematodes. In vitro monoculture growth rate tests, dual confrontation assays and comparison of strain specific egg-parasitic index (EPI) revealed that T. harzianum strains possess the strongest egg-parasitic ability and the best compatibility with M. cionopagum. Because Trichoderma chitinolytic enzyme systems play an important role in egg-parasitism the transcriptional activity of chi18-5 (chit42) and chi18-12 (chit33) of T. harzianum (SZMC 1647) during egg-parasitism were also characterized. The expression patterns of these genes revealed overlapping modes of action and elucidated differences in timing and amplitude of gene induction between the mycoparasitic and egg-parasitic processes.

Tan, Jo-Anne C. H.; Jones, Michael G. K.; Fosu-Nyarko, John. Gene silencing in root lesion nematodes (Pratylenchus spp.) significantly reduces reproduction in a plant host //EXPERIMENTAL PARASITOLOGY Volume: 133 Issue: 2 Pages: 166-178 FEB 2013

Root lesion nematodes (RLNs, Pratylenchus species) are a group of economically important migratory endoparasitic plant pathogens that attack host roots of major crops such as wheat and sugarcane, and can reduce crop yields by 7-15%. Pratylenchus thornei and Pratylenchus zeae were treated with double stranded RNA (dsRNA) to study gene silencing, (RNA interference, RNAi), as a potential strategy for their control. Mixed stages of nematodes of both species ingested dsRNA when incubated in a basic soaking solution in the presence of the neurostimulant octopamine. Incubation for up to 16 h in soaking solutions containing 10-50 mM octopamine, 0.1-1.0 mg/mL FITC, and 0.5-6 mM spermidine did not affect vitality. Spermidine phosphate salt hexahydrate rather than spermidine or spermidine trihydrochloride increased uptake of FITC by nematodes, and this resulted in more effective gene silencing. Silencing pat-10 and unc-87 genes of P. thornei and P. zeae resulted in paralysis and uncoordinated movements in both species, although to a higher degree in P. thornei. There was also a greater reduction in transcript of both genes in P. thornei indicating that it may be more susceptible to RNAi. For P. thornei treated with dsRNA of pat-10 and unc-87 there was a significant reduction (77-81%) in nematode reproduction on carrot mini discs over a 5 week period. The results show that RLNs are clearly amenable to gene silencing, and that in planta delivery of dsRNA to target genes in these nematodes should confer host resistance. Moreover, for the two genes, dsRNA derived from either nematode species silenced the corresponding gene in both species. This implies cross-species control of nematodes via RNAi is possible.

Thomas, Cristel G.; Li, Renhua; Smith, Harold E.; et al.Simplification and Desexualization of Gene Expression in Self-Fertile Nematodes //CURRENT BIOLOGY Volume: 22 Issue: 22 Pages: 2167-2172 NOV 20 2012

Evolutionary transitions between sexual modes could be potent forces in genome evolution [1, 2]. Several Caenorhabditis nematode species have evolved self-fertile hermaphrodites from the obligately outcrossing females of their ancestors [3]. We explored the relationship between sexual mode and global gene expression by comparing two selfing species, C. elegans and C. briggsae, with three phylogenetically informative outcrossing relatives, C. remanei, C. brenneri, and C. japonica. Adult transcriptome assemblies from the selfing species are consistently and strikingly smaller than those of the outcrossing species. Against this background of overall simplification, genes conserved in multiple outcrossing species with strong sex-biased expression are even more likely to be missing from the genomes of the selfing species. In addition, the sexual regulation of remaining transcripts has diverged markedly from the ancestral pattern in both selfing lineages, though in distinct ways. Thus, both the complexity and the sexual specialization of transciptomes are rapidly altered in response to the evolution of self-fertility. These changes may result from the combination of relaxed sexual selection and a recently reported genetic mechanism favoring genome shrinkage [4] in partial selfers.

Toubarro, Duarte; Lucena-Robles, Miguel; Nascimento, Gisela; et al.Serine Protease-mediated Host Invasion by the Parasitic Nematode Steinernema carpocapsae //JOURNAL OF BIOLOGICAL CHEMISTRY Volume: 285 Issue: 40 Pages: 30666-30675 OCT 1 2010

Steinernema carpocapsae is an insect parasitic nematode used in biological control, which infects insects penetrating by mouth and anus and invading the hemocoelium through the midgut wall. Invasion has been described as a key factor in nematode virulence and suggested to be mediated by proteases. A serine protease cDNA from the parasitic stage was sequenced (sc-sp-1); the recombinant protein was produced in an Escherichia coli system, and a native protein was purified from the secreted products. Both proteins were confirmed by mass spectrometry to be encoded by the sc-sp-1 gene. Sc-SP-1 has a pI of 8.7, a molecular mass of 27.3 kDa, a catalytic efficiency of 22.2 x 10(4) s(-1) M(-1) against N-succinyl-Ala-Ala-Pro-Phe-pNA, and is inhibited by chymostatin (IC 0.07) and PMSF (IC 0.73). Sc-SP-1 belongs to the chymotrypsin family, based on sequence and biochemical analysis. Only the nematode parasitic stage expressed sc-sp-1. These nematodes in the midgut lumen, prepared to invade the insect hemocoelium, expressed higher levels than those already in the hemocoelium. Moreover, parasitic nematode sense insect peritrophic membrane and hemolymph more quickly than they do other tissues, which initiates sc-sp-1 expression. Ex vivo, Sc-SP-1 was able to bind to insect midgut epithelium and to cause cell detachment from basal lamina. In vitro, Sc-SP-1 formed holes in an artificial membrane model (Matrigel), whereas Sc-SP-1 treated with PMSF did not, very likely because it hydrolyzes matrix glycoproteins. These findings highlight the S. carpocapsae-invasive process that is a key step in the parasitism thus opening new perspectives for improving nematode virulence to use in biological control.

Travizi, Ana, The nematode fauna of the northern Adriatic offshore sediments: community structure and biodiversity // ACTA ADRIATICA Volume: 51 Issue: 2 DEC 2010

In order to provide a comparative source of data for local (Adriatic Sea) and regional (Mediterranean) biodiversity, as well as for future environmental quality assessments, the pattern of nematode fauna community structure at silty-sand offshore sediment was investigated. The qualitative and quantitative composition of nematofauna was studied at three northern Adriatic offshore sites associated with circalittoral zone and detritic bottom communities. The study involved the main population parameters (density, dominance, constancy) and community attributes (taxonomic composition, abundance, species richness, evenness, diversity, faunistic affinity). From 57 samples collected over a period of two years 12 350 Nematoda specimens were retrieved and subjected to spatial analysis. The results of multivariate analyses indicate high faunistic similarity, both from the qualitative (QS=68-76%) and quantitative aspects (QS=48-56%). The mutual intersection of k-dominance curves suggested the same trend of distribution of individuals per species at all sites investigated. In all, 168 free-living nematode species, comprising 101 genera and 29 families, were recorded. The area investigated is distinguished by considerable taxonomic diversity and respectable species richness (60% of total nematofauna species) in comparison to other Adriatic regions.

Ueno, Shunsuke; Yasutake, Kiichi; Tohyama, Daisuke; et al.Systematic screen for genes involved in the regulation of oxidative stress in the nematode Caenorhabditis elegans //BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Volume: 420 Issue: 3 Pages: 552-557 APR 13 2012

Oxygen is essential for animals, but high concentrations of oxygen are toxic to them probably because of an increase in reactive oxygen species (ROS). Many genes are involved in the regulation of ROS, but they largely remain to be identified. To identify these genes, we employed the nematode Caenorhabditis elegans as a model organism, and systematically screened for genes that, when down-regulated by RNAi, lead to an increased sensitivity to ROS. We examined approximately 2400 genes on linkage group I and found that knock-down of 9 genes which participate in various cellular functions led to an increased sensitivity to ROS. This finding suggests an implication of a variety of cellular processes in the regulation of oxidative stress. (C) 2012 Elsevier Inc. All rights reserved.

Vieira dos Santos, M. C.; Esteves, I.; Abrantes, I.. In vitro water stress bioassays with the nematophagous fungus Pochonia chlamydosporia: Effects on growth and parasitism //BIOLOGICAL CONTROL Volume: 63 Issue: 3 Pages: 310-319 DEC 2012

The biocontrol potential of Pochonia chlamydosporia, a fungus with parasitic activity against economically important plant-parasitic nematodes, can be influenced by abiotic factors such as water availability. The objective of this study was to evaluate the effects of different water stress regimes on in vitro growth, sporulation, germination and parasitism of P. chlamydosporia isolates. The osmotic water potential of 1.7% corn meal agar (CMA) was modified by addition of potassium chloride (KCl) or glycerol, and the matric water potential was modified using polyethylene glycol (PEG 8000). The fungus was able to grow over a range of potentials but radial growth rates decreased with the increase of osmotic and matric stress. No growth was observed at -10 MPa on 1.7% CMA amended with glycerol and at -7.1 MPa on medium with PEG 8000 but all isolates were able to resume growth when transferred onto unmodified 1.7% CMA. The production of chlamydospores was repressed in both osmotic and matric modified media. Although the production of conidia increased in medium modified with KCl, the germination rate was lower. Spores/hyphal fragments remained viable in all isolates that were previously inoculated onto media with growth-limiting water potential (-10 MPa on 1.7% CMA amended with glycerol and -10 MPa on medium with PEG 8000). The percentage of viable conidia produced on 1.7% CMA, after inoculation under osmotic or matric stress conditions for 25 days, was over 74.5% in all isolates (osmotic stress) and ranged from 1% (Pc1) to 65.8% (Pc280) (matric stress). The in vitro infection of potato cyst nematodes, Globodera rostochiensis eggs by P. chlamydosporia isolates, grown under these limiting conditions, was studied using a standard bioassay. The percentage of parasitized eggs was significantly higher under osmotic stress except for isolates Pc2 and Pc3. P. chlamydosporia spores/hyphal fragments can remain viable at water potentials limiting for growth, for prolonged periods of time, suggesting that the osmoregulation mechanisms, used to compensate water stress, affect in vitro sporulation and increased pathogenicity. Knowledge on water requirements of P. chlamydosporia enables a better understanding of its survival and growth strategies in the soil environment and could aid the development of effective strategies to increase the production and quality of inoculum, thus contributing to the implementation of biosafe, sustainable management strategies against plant-parasitic nematodes.

Wang, Chun Yan; Fang, Zhe Ming; Wang, Zhen; et al.. Biological control of the pinewood nematode Bursaphelenchus xylophilus by application of the endoparasitic fungus Esteya vermicola //BIOCONTROL Volume: 56 Issue: 1 Pages: 91-100 FEB 2011

Esteya vermicola (Ophiostomataceae) is the first reported endoparasitic fungus of the pinewood nematode (PWN), Bursaphelenchus xylophilus (Nematoda: Aphelenchoidoidea). It has high in vitro infectivity. In this study, the nematocidal effect of E. vermicola in logs was investigated and evaluated. Two months after inoculation of pine wilt-killed Pinus densiflora logs with E. vermicola conidia suspensions of 3 x 10(8) and 3 x 10(6) ml(-1), the density of nematodes decreased by approximately 79% and 47%, respectively. When the fungus was sprayed on to four-year-old pine seedlings one month before PWN inoculation, the survival index of seedlings reached 0.67 compared with only 0.067 for control seedlings without fungal spraying. These results suggest that conidia spraying of E. vermicola can, to some extent, protect pine trees from wilt disease. Moreover, infected nematodes and hyphae of E. vermicola were observed in the treated wood sections.

Winter, Alan D.; Eschenlauer, Sylvain C. P.; McCormack, Gillian; et al.Loss of secretory pathway FK506-binding proteins results in cold-sensitive lethality and associate extracellular matrix defects in the nematode Caenorhabditis elegans //JOURNAL OF BIOLOGICAL CHEMISTRY Volume: 282 Issue: 17 Pages: 12813-12821 APR 27 2007

The FK506-binding proteins (FKBs) represent ubiquitous enzymes that catalyze the rate-limiting peptidyl prolyl cis-trans isomerization step in protein folding. The nematode Caenorhabditis elegans has eight FKBs, three of which (FKB-3, -4, and -5) have dual peptidyl prolyl cis-trans isomerase (PPIase) domains, signal peptides and ER retention signals. PPIase activity has been detected for recombinant FKB-3. Both FKB-3 and -5 are expressed in the exoskeleton-synthesizing hypodermis with transcript peaks that correspond to the molting and collagen synthesis cycles. FKB-4 is expressed at a low level throughout development. No phenotypes were observed in deletion mutants in each of the secretory pathway FKBs. Combined triple and fkb-4, -5 double deletion mutants were however found to arrest at 12 degrees C, but developed normally at 15-25 degrees C. This cold sensitive larval lethal effect was not maternally derived, occurred during embryogenesis, and could be rescued following the transgenic introduction of a wild type copy of either fkb-4 or fkb-5. The temperature-sensitive defects also affected molting, cuticle collagen expression, hypodermal seam cell morphology, and the structural integrity of the cuticular extracellular matrix. This study establishes that the secretory pathway FK506-binding PPIase enzymes are essential for normal nematode development, collagen biogenesis, and the formation of an intact exoskeleton under adverse physiological conditions.

Yan, Xun; Han, Richou; Moens, Maurice; et al.. Field evaluation of entomopathogenic nematodes for biological control of striped flea beetle, Phyllotreta striolata (Coleoptera: Chrysomelidae) //BIOCONTROL Volume: 58 Issue: 2 Pages: 247-256 APR 2013

The striped flea beetle, Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae) is a key pest of crucifer vegetables in Southern China. The use of entomopathogenic nematodes (EPNs) within an integrated pest management approach may offer an effective and environmentally safe strategy to suppress outbreaks of this pest. In the present study, the efficacy of Steinernema carpocapsae All and Heterorhabditis indica LN2 for the control of P. striolata in the field was evaluated, as well as the combined application of EPNs and azadirachtin against the pest. Both nematode species were capable of reducing populations of the soil-dwelling stages of P. striolata, thus leading to a reduction of the adult populations and the associated shot-hole damage on the leaves. Nematode treatments also increased cabbage yields as compared to the control and azadirachtin treatments alone. Azadirachtin alone was not effective to prevent damage by P. striolata, but it could enhance the control effect of S. carpocapsae shortly after application. Osmotically treated infective juveniles (IJs) of S. carpocapsae All performed as well as untreated IJs.

Zhang, Lin; Yang, Jinkui; Niu, Qiuhong; et al.Investigation on the infection mechanism of the fungus Clonostachys rosea against nematodes using the green fluorescent protein //: APPLIED MICROBIOLOGY AND BIOTECHNOLOGY Volume: 78 Issue: 6 Pages: 983-990 APR 2008

The fungus Clonostachys rosea (syn. Gliocladium roseum) is a potential biocontrol agent. It can suppress the sporulation of the plant pathogenic fungus Botrytis cinerea and kill pathogenic nematodes, but the process of nematode pathogenesis is poorly understood. To help understand the underlying mechanism, we constructed recombinant strains containing a plasmid with both the enhanced green fluorescent protein gene egfp and the hygromycin resistance gene hph. Expression of the green fluorescent protein (GFP) was monitored using fluorescence microscopy. Our observations reveal that the pathogenesis started from the adherence of conidia to nematode cuticle for germination, followed by the penetration of germ tubes into the nematode body and subsequent death and degradation of the nematodes. These are the first findings on the infection process of the fungal pathogen marked with GFP, and the developed method can become an important tool for studying the molecular mechanisms of nematode infection by C. rosea.

Zhao, F; Ohtsuki, T; Yamada, K; et al.. Isolation and physiochemical properties of protein-rich nematode mitochondrial ribosomes //BIOCHEMISTRY Volume: 44 Issue: 25 Pages: 9232-9237 JUN 28 2005

In the present study, mitochondrial ribosomes of the nematode Ascaris suum were isolated and their physiochernical properties were compared to ribosomes of Escherichia coli. The sedimentation coefficient and buoyant density of A. suum mitochondrial ribosomes were determined. The sedimentation coefficient of the intact monosome was about 55 S. The buoyant density of formaldehyde-fixed ribosomes in cesium chloride was 1.40 g/cm(3), which suggests that the nematode mitoribosomes have a much higher protein composition than other mitoribosomes. The diffusion coefficients obtained from dynamic light scattering measurements were (1.48 +/- 0.04) x 10(-7) cm(2) s(-1) for 55 S mitoribosomes and (1.74 +/- 0.04) X 10(-7) cm(2) S-1 for the 70 S E. coli monosome. The diameter of mitoribosomes was measured by dynamic light-scattering analysis and electron microscopy. Though the nematode mitoribosome has a larger size than the bacterial ribosome, it does not differ significantly in size from mammalian mitoribosomes.

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