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Sample records for naturally acquired nematode

  1. Resistance of Santa Ines and crossbred ewes to naturally acquired gastrointestinal nematode infections.

    PubMed

    Amarante, A F T; Susin, I; Rocha, R A; Silva, M B; Mendes, C Q; Pires, A V

    2009-11-12

    This trial was carried out in Piracicaba, São Paulo State, Brazil, to comparatively evaluate the degree of resistance to naturally acquired gastrointestinal nematode infections in sheep of the following genetic groups: purebred Santa Ines (SI), SI crossbred with Dorper (DO x SI), Ile de France (IF x SI), Suffolk (SU x SI), and Texel (TE x SI). Fifteen ewes from each group were raised indoors until 12 months of age. At this age, they were moved to pasture that was naturally contaminated by nematode infective larvae and were evaluated from December to May, 2007. Rainfall ranged from 267 mm in January to 37 mm in April. Maximum and minimum mean temperatures ranged from 32.5 degrees C to 19.0 degrees C in March and from 25.9 degrees C to 12.8 degrees C in May. There was an increase in the mean number of eggs per gram of feces (EPG) after animals were placed on pasture with significant difference between the SI (80 EPG) and IF x SI (347 EPG) groups in January; and the DO x SI (386 EPG) and TE x SI (258 EPG) groups in May. The highest mean fecal egg count (FEC), 2073 EPG, was recorded for the TE x SI group in February. All groups showed a progressive reduction in body weight throughout the experiment of 12.0% (TE x SI) to 15.9% (SU x SI). In general, the animals with the highest FEC presented the lowest packed cell volumes (PCV); the highest correlation coefficient between FEC x PCV occurred in the SU x SI sheep in January (r=-0.70; P<0.01). Similarly, there was an inverse relationship between FEC and blood eosinophil values, with the highest correlation coefficient in the TE x SI sheep in February (r=-0.64; P<0.05). Immunoglobulin G (IgG) levels against Haemonchus contortus antigens increased in all groups as a result of the exposure to parasites and remained relatively constant until the end of the study, with the exceptions of SU x SI and TE x SI, which showed a rise in IgG levels during the last sampling that coincided with a reduction in mean FEC. In conclusion

  2. Efficacy of afoxolaner plus milbemycin oxime chewable tablets against naturally acquired intestinal nematodes in dogs.

    PubMed

    Rehbein, Steffen; Dorr, Paul; Bowman, Dwight D; Crafford, Dionne; Kusi, Ilir; Postoli, Rezart; Yoon, Stephen; Chester, S Theodore; Dollhofer, Doris; Visser, Martin; Larsen, Diane L

    2016-02-15

    The efficacy of oral afoxolaner plus milbemycin oxime combination chewable tablets (NexGard Spectra, Merial) against naturally acquired intestinal nematode infections in dogs was evaluated in six negative control, blinded studies including a total of 114 dogs. Dogs were selected based on a pre-treatment fecal examination indicating patent infections with hookworms (two studies), Toxocara or Toxascaris ascarids (one study each) or Trichuris whipworms (two studies). In each study, dogs were assigned to blocks of two animals each, based on decreasing pre-treatment body weight and were randomly allocated to one of two groups consisting of eight, nine or 10 dogs: untreated (control) or treated with the combination chewable tablet formulation. Chewable tablets were combined to provide doses of actives as close as possible to the minimum effective dose of afoxolaner and milbemycin oxime, i.e., 2.5 mg/kg body weight and 0.5 mg/kg body weight, respectively, once on Day 0. For parasite recovery and count, dogs were euthanized humanely and necropsied seven or eight days after treatment. A single treatment with afoxolaner plus milbemycin oxime chewable tablets provided 94.8% and 90.9% efficacy against adult Ancylostoma braziliense and A. caninum, respectively, 97.8% and 99.4% efficacy against adult Toxocara canis and Toxascaris leonina, respectively, and ≥98.3% efficacy against adult Trichuris vulpis. Compared to untreated controls, nematode counts of the treated dogs were significantly reduced (F-test; p<0.002). In addition, analysis of the pooled data across studies revealed that treatment with afoxolaner plus milbemycin oxime chewable tablets reduced adult Uncinaria stenocephala burdens by 74.9% (p=0.002). All dogs tolerated the treatment well based on clinical observations post-treatment and daily clinical observations. No adverse experiences or other clinical problems related to the treatment were observed throughout the studies. The results of this series of controlled

  3. Resistance of Santa Ines, Suffolk and Ile de France sheep to naturally acquired gastrointestinal nematode infections.

    PubMed

    Amarante, A F T; Bricarello, P A; Rocha, R A; Gennari, S M

    2004-02-26

    A study was conducted to assess the breed resistance against nematode infections in Santa Ines, Ile de France and Suffolk male lambs over a 9-month period in São Paulo state, Brazil. Lambs were born during the winter (year 2000) and were weaned at 2 months of age. The animals were then housed and treated with anthelmintics to eliminate natural infections by gastrointestinal nematodes. In late October 2000, lambs were placed in a paddock, where they stayed until August of the following year. Fecal and blood samples were taken from each animal every 2 weeks. On the same day, a pasture sample was collected to determine the number of infective larvae on the herbage. To prevent deaths, individual treatment with anthelmintics was provided to lambs with fecal egg counts (FEC) higher than 4000 eggs per gram (EPG) or with a packed cell volume (PCV) lower than 21%. In August 2001, all animals were slaughtered and the worms present in samples of the gastrointestinal contents were identified and counted. Most of the Suffolk and Ile de France sheep received three to six anthelmintic treatments over a period of 7 months, while most of the Santa Ines were not treated. Reductions in PCV and plasma protein values associated with high FEC and worm burdens were recorded, particularly, in Suffolk and Ile de France lambs. Haemonchus contortus and Oesophagostomum columbianum burdens and number of nodular lesions caused in the large intestine by O. columbianum larvae were significantly lower in Santa Ines sheep. All three breeds showed similar Trichostrongylus colubriformis worm burdens. The relative resistance of Santa Ines young male sheep was superior to that of Suffolk and Ile de France sheep.

  4. Alveolar mastocytosis and eosinophilia in lambs with naturally acquired nematode infections of Protostrongylus rufescens and Haemonchus contortus.

    PubMed

    Mansfield, L S; Gamble, H R

    1995-12-01

    Specific-pathogen-free Dorset and St. Croix lambs were placed on pasture contaminated with Haemonchus contortus third stage larvae and slugs carrying third stage larvae of Protostrongylus rufescens for an entire grazing season to evaluate breed differences in acquired resistance to these nematodes. Lambs were evaluated for clinical signs, clinical pathology and histopathologic lesions associated with these infections. Both breeds acquired natural infections with H. contortus and lungworm when allowed to graze contaminated pastures for 5 months during the summer and fall in central Maryland. Dorset sheep maintained heavy abomasal worm burdens of H. contortus throughout the grazing period when compared to St. Croix breed sheep. Seven of 12 Dorset sheep and three of 12 St. Croix sheep on pasture acquired heavy lungworm infections after at least 15 weeks of exposure, as evidenced by shedding of first stage larvae in feces and numerous subpleural lung lesions containing adult P. rufescens found at necropsy. All lungworm infected animals had mild respiratory and gastrointestinal signs, and two of five Dorset sheep with both infections had chronic anemia. All lungworm and H. contortus infected Dorset sheep had decreased numbers of circulating white blood cells. There was mastocytosis in the lungs of lungworm infected Dorset and St. Croix sheep when compared to age- and breed-matched control sheep prevented from acquiring both lungworm and trichostrongyle infections. No difference was noted in the number of mast cells in the abomasum, duodenum and skin of infected and non-infected Dorset sheep. A morphologic range of mast cell forms was observed in the lungs of infected sheep including transitional cells and globular leukocytes. The number of eosinophils was significantly greater in the lungs but not in the abomasum of infected sheep. Despite the pronounced cellular infiltrates surrounding the adult lungworms, they were viable on recovery and appeared undamaged when

  5. Confirmation of the efficacy of a combination tablet of spinosad and milbemycin oxime against naturally acquired infections of canine intestinal nematode parasites.

    PubMed

    Schnitzler, Beate; Hayes, Brad; Wiseman, Scott; Snyder, Daniel E

    2012-03-23

    Four separate controlled and blinded studies were conducted to confirm the dose of spinosad and milbemycin oxime (MO) administered orally in combination to dogs for the treatment and control of naturally acquired infections of adult whipworm (Trichuris vulpis), hookworm (Ancylostoma caninum) and ascarids (Toxocara canis, Toxascaris leonina). Dogs were allocated randomly based on pre-treatment quantitative nematode egg counts of each species of interest to one of two treatment groups of 10 or 11 animals each. In each study, spinosad and MO in combination, was given orally to dogs using the lower half (30-45 mg/kg spinosad; 0.5-0.75 mg/kg MO) of the US commercial dose band (30-60 mg/kg spinosad; 0.5-1.0mg/kg MO) of each active ingredient on Day 0 using a tablet formulation. A corresponding vehicle control group was treated similarly in each individual study. Dogs were necropsied post-treatment on Day 7/8. All nematodes in the intestinal tract collected at necropsy were identified and counted by species and stage. The spinosad and MO combination group demonstrated significantly different adult intestinal nematode efficacy in each individual study as compared to the vehicle control group. Efficacy values for whipworm, hookworm, T. canis and T. leonina were 100%, 99.8%, 100%, 93.3%, respectively. Minor non-serious adverse events were observed in a small number of control and treated dogs that were attributed primarily to the natural nematode infections. In summary, flavored spinosad and MO combination tablets administered orally to dogs were both safe and highly efficacious delivering >93% up to 100% adult intestinal nematode control in naturally infected dogs.

  6. Evaluation and application of a molecular method to assess the composition of strongylid nematode populations in sheep with naturally acquired infections.

    PubMed

    Roeber, Florian; Jex, Aaron R; Campbell, Angus J D; Campbell, Bronwyn E; Anderson, Garry A; Gasser, Robin B

    2011-07-01

    We evaluated the performance of a PCR method for the diagnosis of naturally acquired strongylid nematode infections in sheep (n = 470; in a temperate climatic zone of south-eastern Australia), using a panel of 100 'negative control' samples from sheep known not to harbour parasitic helminths. We compared the diagnostic sensitivity (98%) and specificity (100%) of this assay against a conventional faecal flotation method and also established a system to rank the contribution of particular strongylid nematodes to the faecal egg counts (FECs) from 'mixed infections' in individual sheep. The testing of faecal samples herein revealed that Teladorsagia circumcincta (80%) and Trichostrongylus spp. (66%) were most prevalent, followed by Chabertia ovina (33%), Oesophagostomum venulosum (28%) and Haemonchus contortus (1%). For the majority of sheep in this study, T. circumcincta and Trichostrongylus spp. represented the largest proportion of strongylid eggs in faecal samples from individual sheep. This is the first large-scale prevalence survey of gastrointestinal nematodes in live sheep using a molecular tool. The ability to rapidly rank strongylid nematodes according to their contribution to mixed infections represents a major advantage over routine coprological methods. This PCR tool has the potential to replace the conventional technique of larval culture. Future efforts will focus on enhancing and adapting this molecular method for high throughput application in routine, diagnostic settings.

  7. The efficacy of eprinomectin extended-release injection against naturally acquired nematode parasites of cattle, with special regard to inhibited fourth-stage Ostertagia larvae.

    PubMed

    Hunter, J S; Yoon, S; Yazwinski, T A; Williams, J C; Rehbein, S

    2013-03-01

    The efficacy of eprinomectin in an extended-release injection (ERI) formulation in the treatment of cattle harboring naturally acquired nematode populations (including inhibited nematodes) was evaluated. Five studies were conducted under a similar protocol in the USA, the UK, and in Germany. All study animals were infected by grazing naturally contaminated pastures. The adequacy of pasture infectivity was confirmed by examining tracer calves prior to allocation and treatment of the study animals. The cattle were of various breeds or crosses, weighing 79-491 kg, and aged approximately 6-15 months. In each study, 20 animals were infected by grazing, and then removed from pasture and housed in a manner to preclude further nematode infections for 8-16 days until treatment. Animals were blocked based on descending pre-treatment body weight and randomly allocated to one of two treatments: ERI vehicle (control) at 1 mL/50 kg body weight or eprinomectin 5% (w/v) ERI at 1 mL/50 kg body weight (1.0 mg eprinomectin/kg). Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. For parasite recovery and count, all study animals were humanely euthanized 14/15 days after treatment. Cattle treated with eprinomectin ERI had significantly (p<0.05) fewer of the following nematodes than the controls with overall reduction of parasite counts of ≥94%: adult Dictyocaulus viviparus, Capillaria spp., Cooperia oncophora, Cooperia pectinata, Cooperia punctata, Cooperia surnabada, Haemonchus placei, Nematodirus helvetianus, Oesophagostomum radiatum, Ostertagia lyrata, Ostertagia ostertagi, Trichostrongylus axei, Trichostrongylus colubriformis, Trichuris discolor, Trichuris skrjabini, and Trichuris spp.; developing fourth-stage larvae of Ostertagia spp. and Trichostrongylus spp.; and inhibited fourth-stage larvae of Cooperia spp., Haemonchus spp., Nematodirus spp., Oesophagostomum spp., Ostertagia spp., and Trichostrongylus spp. Animal treatments were

  8. Field evaluations of the efficacy and safety of Emodepside plus toltrazuril (Procox® oral suspension for dogs) against naturally acquired nematode and Isospora spp. infections in dogs.

    PubMed

    Altreuther, Gertraut; Gasda, Nadine; Adler, Kerstin; Hellmann, Klaus; Thurieau, Heloise; Schimmel, Annette; Hutchens, Douglas; Krieger, Klemens J

    2011-08-01

    Three controlled, blinded and randomised multicentre field studies evaluated the efficacy and safety of a new formulation containing emodepside plus toltrazuril (Procox® suspension for dogs) against naturally acquired parasite infections in dogs. In two studies dogs positive for gastrointestinal nematodes and/or Isospora spp. were treated with emodepside/toltrazuril suspension (at least 0.45 mg emodepside plus 9 mg toltrazuril per kg body weight) or a reference product containing either milbemycin oxime plus praziquantel (Milbemax®) or sulfadimethoxine (Kokzidiol SD®) at recommended dose rates. The third study investigated efficacy against prepatent natural Isospora spp. infections in comparison to an untreated control group by enrolling Isospora- negative dogs that were at risk to develop a patent infection during the study.No suspected adverse drug reactions were observed in any of the 403 dogs enrolled in the three studies including 234 dogs treated with emodepside/toltrazuril suspension. In dogs treated with emodepside/toltrazuril suspension against nematode infection faecal egg counts were reduced by 100 % (reference product: 99.7 %). Similarly, in the dogs that had been treated against patent Isospora spp. infection, faecal oocyst counts were reduced by 100 % (reference product: 99.0 %). In both studies, statistical analysis demonstrated non-inferiority and even superiority to the reference products (p ≤ 0.009). Dogs treated with emodepside/toltrazuril suspension during suspected prepatent Isospora spp. infection had 98.7 % lower faecal oocyst counts after treatment compared to untreated dogs (p < 0.0001).The studies demonstrated that emodepside/toltrazuril suspension is safe and highly efficacious against nematodes and Isospora spp. under field conditions.

  9. The strategic use of closantel and albendazole in controlling naturally acquired gastrointestinal nematodes of sheep in the Kenya highlands.

    PubMed

    Maingi, N; Thamsborg, S M; Gichohi, V M; Munyua, W K; Gathuma, J M

    1997-11-01

    The strategic use of closantel, a narrow-spectrum salicylanilide anthelmintic against bloodsucking helminths, and of albendazole, a broad-spectrum benzimidazole anthelmintic, in the control of gastrointestinal nematodes of sheep was investigated on a farm in Nyandarua District in the highlands of Kenya. Thirty Corriedale female lambs aged between 9 and 12 months were assigned to three treatment groups of 10 lambs each. The three groups were set stocked on separate paddocks for 12 months. Lambs in group 1 (strategic treatment group) were treated with closantel and albendazole at the beginning and towards the end of the long rains (April and June, respectively) and towards the end of the short rains. (December). During the intervening dry season, the lambs were treated with albendazole. Lambs in group 2 (suppressive treatment group) were kept 'worm free' by regular deworming with albendazole at 3-weekly intervals for 12 months. The third group of lambs remained untreated (control group). Gastrointestinal nematode infections and pasture infectivity were well controlled in the case of the strategic treatment group. This resulted in higher weight gains, wool production, packed cell volume, and serum albumin and protein concentrations compared with the untreated control lambs. These parameters were comparable between the strategic treatment and the suppressive treatment groups of lambs. It was concluded that worm control strategies based on the epidemiology of the parasites and the sustained anthelmintic action of closantel in combination with broad-spectrum anthelmintics can provide effective control of gastrointestinal nematodes of sheep in the study area.

  10. Efficacy of a novel topical fipronil, (S)-methoprene, eprinomectin and praziquantel combination against naturally acquired intestinal nematode and cestode infections in cats.

    PubMed

    Knaus, Martin; Abu-Madi, Marawan A; Ibarra-Velarde, Froylán; Kok, Dawie J; Kusi, Ilir; Postoli, Rezart; Chester, S Theodore; Rosentel, Joseph; Alva, Roberto; Irwin, Jennifer; Visser, Martin; Winter, Renate; Rehbein, Steffen

    2014-04-28

    The efficacy of a novel topical combination formulation of fipronil, (S)-methoprene, eprinomectin and praziquantel against naturally acquired intestinal nematode and cestode infections in cats was evaluated in seven negative control, blinded studies. Cats were selected based on a pre-treatment faecal examination indicating a patent infection with at least hookworms (two studies), Toxocara ascarids (one study), taeniid cestodes (two studies) or Dipylidium cestodes (two studies). In each study, cats were assigned randomly to blocks of two animals each, based on decreasing pre-treatment body weight and were randomly allocated to one of two groups of six to 12 cats: untreated (control) or treated with topical fipronil (8.3%, w/v), (S)-methoprene (10%, w/v), eprinomectin (0.4%, w/v) and praziquantel (8.3%, w/v) (BROADLINE(®), Merial) at 0.12 mL/kg body weight (providing a minimum of 10mg fipronil+12 mg S-methoprene+0.5mg eprinomectin+10mg praziquantel per kg body weight). The topical treatment was administered directly on the skin in the midline of the neck in a single spot once on Day 0. For parasite recovery and count, cats were euthanized humanely and necropsied seven or ten days after treatment. A single treatment with the novel topical combination product provided 91% efficacy against Ancylostoma braziliense, ≥ 99% efficacy against Ancylostoma tubaeforme, and >97% efficacy against Toxocara cati. Similarly, excellent efficacy was established against Taenia taeniaeformis, Dipylidium caninum and Diplopylidium spp. as demonstrated by >97% and up to 100% reductions of cestode counts in the treated cats when compared to the untreated controls (P<0.01). All cats accepted the treatment well based on health observations post-treatment and daily health observations. No adverse experiences or other health problems were observed throughout the studies. The results of this series of controlled studies demonstrated high efficacy and excellent acceptability of the novel

  11. Field evaluation of the efficacy and safety of a combination of spinosad and milbemycin oxime in the treatment and prevention of naturally acquired flea infestations and treatment of intestinal nematode infections in dogs in Europe.

    PubMed

    Hayes, Brad; Schnitzler, Beate; Wiseman, Scott; Snyder, Daniel E

    2015-01-15

    Two separate randomised, blinded, multicentre field trials were conducted to evaluate the efficacy and safety of a combination of spinosad and milbemycin oxime (MO) (Trifexis(®), Elanco Animal Health) in the treatment and prevention of naturally acquired flea infestations and intestinal nematode infections in European dogs. Treatments using Trifexis(®) and each control veterinary product (CVP) were administered once on Day 0 in both field studies. In the flea field trial, 11 veterinary clinics in France participated in the study. On Day 0, whole body flea comb counts were conducted on all dogs being evaluated for enrolment. Dogs with ≥7 fleas on Day 0 were enrolled, treated once on Day 0 with spinosad/MO or the CVP (Stronghold(®); selamectin) and then underwent post-treatment flea counts on Days 14 and 30. There were 150 spinosad/MO treated dogs and 71 CVP treated dogs included in the flea effectiveness population. Effectiveness against fleas (% reduction in geometric means; GM) was 98.97% and 97.37% for the spinosad/MO treated dogs, and 97.43% and 93.96% for the CVP dogs on Days 14 and 30, respectively, compared to the pre-treatment baseline flea counts. Of the spinosad/MO dogs, 89.3% and 80.0% had no live fleas on Days 14 and 30, compared to 77.5% and 70.4% of the CVP dogs, respectively. In the nematode field trial, data from 10 veterinary clinics in France and 19 in Ireland were pooled. Faecal samples from dogs at each clinic were analysed. A positive result at screening (parasite eggs from Toxocara canis, Toxascaris leonina, Trichuris vulpis or Ancylostoma caninum) allowed for enrolment. Dogs were randomised to spinosad/MO or the CVP (Milbemax(®); MO/praziquantel). On Day 8, a post-treatment faecal sample was taken and analysed. Of 2333 dogs screened for nematode eggs, 238 dogs were positive with one or more of these nematodes, and 229 were enrolled in the study. Of the 229 dogs, 151 were treated with a single dose of spinosad/MO, and 77 were treated with

  12. Field evaluation of the efficacy and safety of emodepside plus praziquantel tablets (Profender tablets for dogs) against naturally acquired nematode and cestode infections in dogs.

    PubMed

    Altreuther, Gertraut; Radeloff, Isabelle; LeSueur, Christophe; Schimmel, Annette; Krieger, Klemens J

    2009-08-01

    A controlled, blinded and randomised multicentre field study evaluated the efficacy and safety of a new anthelmintic tablet formulation containing emodepside plus praziquantel (Profender tablets for dogs) in the treatment of gastrointestinal nematode and cestode infections in dogs in France, Germany, Portugal and Slovakia. Dogs positive for nematodes and/or cestodes (demonstrated by faecal egg counts and/or the presence of proglottids) were treated with emodepside plus praziquantel tablets (n = 239) or the reference product containing milbemycin oxime and praziquantel (Milbemax [n = 115]) at the recommended dose rate. Two faecal samples collected between 7 and 13 days after treatment were evaluated for proglottids, nematode and cestode eggs. No suspected adverse drug reactions were observed in the study. The following parasite species were identified: Trichuris vulpis, Toxocara canis, Toxascaris leonina, Uncinaria stenocephala, Ancylostoma caninum, Dipylidium caninum, Taeniidae and Mesocestoides spp. Geometric mean nematode egg counts in dogs treated with emodepside plus praziquantel tablets were reduced by 99.9 % compared with a reduction of 99.6 % for the reference product. Statistical analysis demonstrated noninferiority of investigational versus reference product (p = 0.0342). None of the dogs treated with emodepside plus praziquantel or reference product remained positive for cestodes after treatment. The study demonstrated that emodepside plus praziquantel tablets are safe and highly efficacious against a broad spectrum of nematodes and cestodes under field conditions.

  13. Resistance and resilience of traditionally managed West African Dwarf goats from the savanna zone of northern Nigeria to naturally acquired trypanosome and gastrointestinal nematode infections.

    PubMed

    Behnke, J M; Chiejina, S N; Musongong, G A; Nnadi, P A; Ngongeh, L A; Abonyi, F O; Fakae, B B

    2011-03-01

    A survey was conducted of gastrointestinal nematode infections and trypanosomosis in Nigerian West African Dwarf (WAD) goats from the savanna region of the country. Animals were screened at two markets, Gboko and Akpagher, from the beginning of April until the end of September, coinciding with the end of the dry season and the first 5 months of the wet season. Of 1054 goats that were examined, 80.5% carried gastrointestinal (GI) nematodes belonging to the genera Haemonchus (61.0%), Oesophagostomum (21.0%) and Trichostrongylus (17.9%). Faecal egg counts (FEC) increased very slowly but significantly from April to maximum levels in September, and varied marginally between the two market sources. The majority of goats (68.8 and 70.1% at the two markets) had low FEC not exceeding 50 eggs/g (epg). FEC did not differ significantly between the sexes or between age classes. Packed cell volume (PCV) also declined significantly with month of the study, but was affected by host sex (a significant month x sex interaction) being generally higher in male animals throughout the period. There was a highly significant negative correlation between log₁₀(FEC+1) and PCV, when all other factors had been taken into account. Body condition scores (BCS) also declined with month of the study, but there was a marked difference between the two sexes, with male animals generally showing a greater stability of BCS across the months compared with females. Trypanosome infections were found in only 4% of the goats and only during the rainy season. Most infections (92.86%) were caused by Trypanosoma brucei alone although T. vivax and T. congolense were occasionally detected. Overall, the majority of goats sampled each month maintained generally good body condition (BCS 3.0-5.0), normal or slightly reduced PCV, even when concurrently infected with trypanosomes and GI nematodes. However, four concurrently infected goats showed signs of overt anaemia during periods of peak infection, during the

  14. Field evaluation of the efficacy and the safety of a combination of oxantel/pyrantel/praziquantel in the treatment of naturally acquired gastrointestinal nematode and/or cestode infestations in dogs in Europe.

    PubMed

    Grandemange, E; Claerebout, E; Genchi, C; Franc, M

    2007-04-10

    In five multicentre field trials, the efficacy and safety of a combination of oxantel/pyrantel/praziquantel (Dolpac), Vetoquinol SA) in the treatment of naturally acquired gastrointestinal nematode and/or cestode infestation in dogs was evaluated in northern and southern Europe. Forty-eight investigators from France, Belgium, Germany, Italy and Spain enrolled 329 dogs to be treated with the tested combination; 235 of these dogs complied with the inclusion criteria of the protocol and had a tested helminth identified on Day 0. A pooled analysis was performed on each of the following helminth species: Toxocara canis, Ancylostoma caninum, Toxascaris leonina, Trichuris vulpis, Uncinaria stenocephala, Taenia spp. and Dipylidium caninum, which were isolated on Day 0. The main efficacy criterion was the egg per gram (epg) percent reduction of the nematodes and the absence of proglottids and or eggs for the cestodes. After treatment, dogs were examined on Day 7, Day 14 and Day 21. The efficacy of the combination against Toxocara canis was 99.1%, 98.8% and 98.9% on Day 7, Day 14 and Day 21, respectively. At the same occasions the efficacy was, respectively, 99.2%, 99.2% and 99.3% against Ancylostoma caninum, 97.3%, 97.2% and 98.4% against Trichuris vulpis, 98.4%, 98.8% and 98.8% against Uncinaria stenocephala, 98.9%, 99.5% and 99.9% against Toxascaris leonina, 97.1%, 100% and 100% against Dipylidium caninum and 100% against Taenia spp.

  15. Naturally acquired microchimerism

    PubMed Central

    Eikmans, Michael; van Halteren, Astrid GS; van Besien, Koen; van Rood, Jon J; Drabbels, Jos JM; Claas, Frans HJ

    2014-01-01

    Microchimerism represents a condition where one individual harbors genetically distinct cell populations, and the chimeric population constitutes <1% of the total number of cells. The most common natural source of microchimerism is pregnancy. The reciprocal cell exchange between a mother and her child often leads to the stable engraftment of hematopoietic and non-hematopoietic stem cells in both parties. Interaction between cells from the mother and those from the child may result in maternal immune cells becoming sensitized to inherited paternal alloantigens of the child, which are not expressed by the mother herself. Vice versa, immune cells of the child may become sensitized toward the non-inherited maternal alloantigens of the mother. The extent of microchimerism, its anatomical location, and the sensitivity of the techniques used for detecting its presence collectively determine whether microchimerism can be detected in an individual. In this review, we focus on the clinical consequences of microchimerism in solid organ and hematopoietic stem cell transplantation, and propose concepts derived from data of epidemiologic studies. Next, we elaborate on the latest molecular methodology, including digital PCR, for determining in a reliable and sensitive way the extent of microchimerism. For the first time, tools have become available to isolate viable chimeric cells from a host background, so that the challenges of establishing the biologic mechanisms and function of these cells may finally be tackled. PMID:24762743

  16. Nature and Inheritance of Nematode Resistance in Cereals

    PubMed Central

    Cook, R.

    1974-01-01

    Resistance to a number of nematodes is present in varieties of temperate and tropical cereals. The occurrence, nature, and inheritance of varietal resistance in cereals is reviewed. Evaluation of the practical significance of nematode resistance in a particular host-nematode combination is discussed in relation to host efficiency, host sensitivity, genetic control of resistance, and presence of virulence in the nematode population. PMID:19308117

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

    PubMed

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

    2007-06-01

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

  18. Natural variation in chemosensation: lessons from an island nematode

    PubMed Central

    McGaughran, Angela; Morgan, Katy; Sommer, Ralf J

    2013-01-01

    All organisms must interact with their environment, responding in behavioral, chemical, and other ways to various stimuli throughout their life cycles. Characterizing traits that directly represent an organism's ability to sense and react to their environment provides useful insight into the evolution of life-history strategies. One such trait for the nematode Pristionchus pacificus, chemosensation, is involved in navigation to beetle hosts. Essential for the survival of the nematode, chemosensory behavior may be subject to variation as nematodes discriminate among chemical cues to complete their life cycle. We examine this hypothesis using natural isolates of P. pacificus from La Réunion Island. We select strains from a variety of La Réunion beetle hosts and geographic locations and examine their chemoattraction response toward organic compounds, beetle washes, and live beetles. We find that nematodes show significant differences in their response to various chemicals and are able to chemotax to live beetles in a novel assay. Further, strains can discriminate among different cues, showing more similar responses toward beetle washes than to organic compounds in cluster analyses. However, we find that variance in chemoattraction response is not significantly associated with temperature, location, or beetle host. Rather, strains show a more concerted response toward compounds they most likely directly encounter in the wild. We suggest that divergence in odor-guided behavior in P. pacificus may therefore have an important ecological component. PMID:24455150

  19. Acquired Tolerance to Ivermectin and Moxidectin after Drug Selection Pressure in the Nematode Caenorhabditis elegans.

    PubMed

    Ménez, Cécile; Alberich, Mélanie; Kansoh, Dalia; Blanchard, Alexandra; Lespine, Anne

    2016-08-01

    Ivermectin and moxidectin are the most widely administered anthelmintic macrocyclic lactones (MLs) to treat human and animal nematode infections. Their widespread and frequent use has led to a high level of resistance to these drugs. Although they have the same mode of action, differences in terms of selection for drug resistance have been reported. Our objective was to study and compare changes occurring upon ivermectin or moxidectin selection in the model nematode Caenorhabditis elegans C. elegans worms were submitted to stepwise exposure to increasing doses of moxidectin. The sensitivity of moxidectin-selected worms to MLs was determined in a larval development assay and compared with those of wild-type and ivermectin-selected strains. Selection with either ivermectin or moxidectin led to acquired tolerance to ivermectin, moxidectin, and eprinomectin. Importantly, moxidectin was the most potent ML in both ivermectin- and moxidectin-selected strains. Interestingly, this order of potency was also observed in a resistant Haemonchus contortus isolate. In addition, ivermectin- and moxidectin-selected strains displayed constitutive overexpression of several genes involved in xenobiotic metabolism and transport. Moreover, verapamil potentiated sensitivity to ivermectin and moxidectin, demonstrating that ABC transporters play a role in ML sensitivity in ML-selected C. elegans strains. Finally, both ivermectin- and moxidectin-selected strains displayed a dye-filling-defective phenotype. Overall, this work demonstrated that selection with ivermectin or moxidectin led to cross-resistance to several MLs in nematodes and that the induction of detoxification systems and defects in the integrity of amphidial neurons are two mechanisms that appear to affect the responsiveness of worms to both ivermectin and moxidectin. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  20. Acquired Tolerance to Ivermectin and Moxidectin after Drug Selection Pressure in the Nematode Caenorhabditis elegans

    PubMed Central

    Alberich, Mélanie; Kansoh, Dalia; Blanchard, Alexandra; Lespine, Anne

    2016-01-01

    Ivermectin and moxidectin are the most widely administered anthelmintic macrocyclic lactones (MLs) to treat human and animal nematode infections. Their widespread and frequent use has led to a high level of resistance to these drugs. Although they have the same mode of action, differences in terms of selection for drug resistance have been reported. Our objective was to study and compare changes occurring upon ivermectin or moxidectin selection in the model nematode Caenorhabditis elegans. C. elegans worms were submitted to stepwise exposure to increasing doses of moxidectin. The sensitivity of moxidectin-selected worms to MLs was determined in a larval development assay and compared with those of wild-type and ivermectin-selected strains. Selection with either ivermectin or moxidectin led to acquired tolerance to ivermectin, moxidectin, and eprinomectin. Importantly, moxidectin was the most potent ML in both ivermectin- and moxidectin-selected strains. Interestingly, this order of potency was also observed in a resistant Haemonchus contortus isolate. In addition, ivermectin- and moxidectin-selected strains displayed constitutive overexpression of several genes involved in xenobiotic metabolism and transport. Moreover, verapamil potentiated sensitivity to ivermectin and moxidectin, demonstrating that ABC transporters play a role in ML sensitivity in ML-selected C. elegans strains. Finally, both ivermectin- and moxidectin-selected strains displayed a dye-filling-defective phenotype. Overall, this work demonstrated that selection with ivermectin or moxidectin led to cross-resistance to several MLs in nematodes and that the induction of detoxification systems and defects in the integrity of amphidial neurons are two mechanisms that appear to affect the responsiveness of worms to both ivermectin and moxidectin. PMID:27246778

  1. Naturally Acquired Canine Herpesvirus-Associated Meningoencephalitis.

    PubMed

    Jager, Mason C; Sloma, Erica A; Shelton, Morgan; Miller, Andrew D

    2017-09-01

    Canid alphaherpesvirus 1 (CHV) causes morbidity and mortality in susceptible puppies. While the neuropathology of experimentally infected puppies has been detailed, characterization of naturally acquired infections is limited. The aim of this study was to describe the histologic, immunohistochemical, and in situ hybridization features of CHV encephalitis in the dog. Six female and 11 male puppies ranging in age from stillborn to 57 days old were included. Histologically, lesions included multifocal glial nodules (16/17, 94%), meningeal infiltrates (15/17, 88%), and cerebellar cortical necrosis (6/9, 67%); however, robust inflammation was not a significant feature in any of the cases. Immunohistochemistry for CD3, CD20, MAC387, and Iba1 was performed. Although T cells predominated over B cells, the overall number of cells was small in all cases both within the glial nodules and the meninges. In 16 of 16 (100%) cases, glial nodules were diffusely immunoreactive for Iba1; however, limited or no immunoreactivity for MAC387 was present. In situ hybridization directed at the CHV thymidine kinase gene revealed CHV nucleic acid in the granule neurons of the cerebellar folia (8/9; 89%), endothelial cells in the meninges and parenchyma (12/17, 71%), and individual randomly distributed neurons (6/17, 35%). These results clarify the pathology of naturally acquired CHV infection and indicate that developing cerebellar granule neurons are an important site of viral replication.

  2. Expressional and functional variation of horizontally acquired cellulases in the nematode Pristionchus pacificus.

    PubMed

    Schuster, Lisa N; Sommer, Ralf J

    2012-09-15

    Various whole genome-sequencing projects in the nematode phylum have revealed the widespread occurrence of horizontal gene transfer from different sources. Pristionchus pacificus was the first non-plant parasitic nematode that was found to contain cellulase genes in its genome and to have cellulolytic activity when grown in a monoxenic culture on Escherichia coli. The P. pacificus reference strain PS312 has seven cellulase genes, all of which were acquired by horizontal gene transfer. Previous phylogenomic studies indicated that the acquisition occurred at the base of the genus Pristionchus and was followed by rapid gene duplications and gene turnover. However, little was known about the protein domain architecture, gene expression and the functionality of individual proteins. Here, we analyzed the protein domain architecture, studied the expression at various developmentally stages and tried to induce cellulase gene expression by feeding nematodes with different polysaccharides. Only two of the encoded proteins, Ppa-CEL-2 and Ppa-CEL-3, have a carbohydrate-binding module. Interestingly, these were also the ones with developmental gene expression regulation. Ppa-cel-2 shows high expression in larval and adult stages but is only low expressed in eggs, while Ppa-cel-3 is highly upregulated in adult worms but hardly detectable in any other stage. Ppa-CEL-1, has a catalytic domain similar to Ppa-CEL-2 and Ppa-CEL-3, but lacks a carbohydrate-binding module. The other four cellulases have a very low transcriptional expression correlating with putative incompleteness of their catalytic domain. While, the expression of none of the genes is inducible by polysaccharides, zymographic studies and mass spectrometry indicate that Ppa-CEL-2 and Ppa-CEL-3 are the only two cellulases contributing to cellulase activity in carboxymethylcellulose. Thus, the cellulases of P. pacificus differ in their protein domain architecture, gene expression and functionality. These results indicate

  3. Microsporidia Are Natural Intracellular Parasites of the Nematode Caenorhabditis elegans

    PubMed Central

    Troemel, Emily R; Félix, Marie-Anne; Whiteman, Noah K; Barrière, Antoine; Ausubel, Frederick M

    2008-01-01

    For decades the soil nematode Caenorhabditis elegans has been an important model system for biology, but little is known about its natural ecology. Recently, C. elegans has become the focus of studies of innate immunity and several pathogens have been shown to cause lethal intestinal infections in C. elegans. However none of these pathogens has been shown to invade nematode intestinal cells, and no pathogen has been isolated from wild-caught C. elegans. Here we describe an intracellular pathogen isolated from wild-caught C. elegans that we show is a new species of microsporidia. Microsporidia comprise a large class of eukaryotic intracellular parasites that are medically and agriculturally important, but poorly understood. We show that microsporidian infection of the C. elegans intestine proceeds through distinct stages and is transmitted horizontally. Disruption of a conserved cytoskeletal structure in the intestine called the terminal web correlates with the release of microsporidian spores from infected cells, and appears to be part of a novel mechanism by which intracellular pathogens exit from infected cells. Unlike in bacterial intestinal infections, the p38 MAPK and insulin/insulin-like growth factor (IGF) signaling pathways do not appear to play substantial roles in resistance to microsporidian infection in C. elegans. We found microsporidia in multiple wild-caught isolates of Caenorhabditis nematodes from diverse geographic locations. These results indicate that microsporidia are common parasites of C. elegans in the wild. In addition, the interaction between C. elegans and its natural microsporidian parasites provides a system in which to dissect intracellular intestinal infection in vivo and insight into the diversity of pathogenic mechanisms used by intracellular microbes. PMID:19071962

  4. Natural and acquired macrolide resistance in mycobacteria.

    PubMed

    Doucet-Populaire, F; Buriánková, K; Weiser, J; Pernodet, J-L

    2002-12-01

    The genus Mycobacterium contains two of the most important human pathogens, Mycobacterium tuberculosis and Mycobacterium leprae, the etiologic agents of tuberculosis and leprosy, respectively. Other mycobacteria are mostly saprophytic organisms, living in soil and water, but some of them can cause opportunistic infections. The increasing incidence of tuberculosis as well as infections with non-tuberculous mycobacteria (NTM) in AIDS patients has renewed interest in molecular mechanisms of drug resistance in these pathogens. Mycobacteria show a high degree of intrinsic resistance to most common antibiotics. For instance, species from the M. tuberculosis complex (MTC) are intrinsically resistant to macrolides. Nevertheless, some semi-synthetic macrolides as the erythromycin derivatives clarithromycin, azithromycin and most recently the ketolides, are active against NTM, particularly Mycobacterium avium, and some of them are widely used for infection treatment. However, shortly after the introduction of these new drugs, resistant strains appeared due to mutations in the macrolide target, the ribosome. The mycobacterial cell wall with its specific composition and structure is considered to be a major factor in promoting the natural resistance of mycobacteria to various antibiotics. However, to explain the difference in macrolide sensitivity between the MTC and NTM, the synergistic contribution of a specific resistance mechanism might be required, in addition to possible differences in cell wall permeability. This mini-review summarizes the current knowledge on the natural and acquired macrolide resistance in mycobacteria, gives an overview of potential mechanisms implicated in the intrinsic resistance and brings recent data concerning a macrolide resistance determinant in the MTC.

  5. Unravelling parasitic nematode natural history using population genetics.

    PubMed

    Gilabert, Aude; Wasmuth, James D

    2013-09-01

    The health and economic importance of parasitic nematodes cannot be overstated. Moreover, they offer a complex and diverse array of life strategies, raising a multitude of evolutionary questions. Researchers are applying population genetics to parasitic nematodes in order to disentangle some aspects of their life strategies, improve our knowledge about disease epidemiology, and design control strategies. However, population genetics studies of nematodes have been constrained due to the difficulty in sampling nematodes and developing molecular markers. In this context, new computational and sequencing technologies represent promising tools to investigate population genomics of parasitic, non-model, nematode species in an epidemiological context. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Nematodes Associated with Plants from Naturally Acidic Wetlands Soil

    PubMed Central

    Cox, Robert John; Smart, Grover C.

    1994-01-01

    Four plants, Cyperus ochraceus, Eriocaulon compressum, Lythrum alatum, and Xyris jupicai, growing along the shoreline of an oligotrophic lake in north central Florida were sampled for nematodes. The nematodes recovered were placed in four trophic groups: bacterivores, herbivores, omnivores, and predators. When the nematodes on all plants were considered, 27% were bacterivores, 23% were herbivores, 7% were omnivores, and 43% were predators. Tripyla was the dominant predator and the dominant genus of all nematodes, and Malenchus was the dominant herbivore. Dominance was not clearly pronounced in the other trophic groups. PMID:19279927

  7. Safety and Efficacy of Antimicrobial Peptides against Naturally Acquired Leishmaniasis

    PubMed Central

    Alberola, J.; Rodríguez, A.; Francino, O.; Roura, X.; Rivas, L.; Andreu, D.

    2004-01-01

    Leishmaniases, which are important causes of morbidity and mortality in humans and dogs, are extremely difficult to treat. Antimicrobial peptides are rarely used as alternative treatments for naturally acquired parasitic diseases. Here we report that the acylated synthetic antimicrobial peptide Oct-CA(1-7)M(2-9) is safe and effective for treating naturally acquired canine leishmaniasis. PMID:14742227

  8. Natural infection of free-range chickens with the ascarid nematode Toxocara sp.

    PubMed

    Campos-da-Silva, Danielle R; da Paz, Jeanne S; Fortunato, Viviane R; Beltrame, Marcus A V; Valli, Luis C P; Pereira, Fausto E L

    2015-11-01

    Human toxocariasis may be acquired by eating raw chicken liver. However, there are no reports on the prevalence of natural infection of chickens with Toxocara. The aim of this study was to evaluate the presence of anti-Toxocara antibodies as indicators of natural infection with Toxocara, in free-range chickens from Espírito Santo State, Brazil. An ELISA test with secretory and excretory Toxocara canis antigens was used. Negative controls were 20 industrial chickens reared in a high hygiene standard environment. Positive control serum was from a chicken infected with embryonated eggs of T. canis. Sera were adsorbed with Ascaridia galli extract to reduce cross-reactivity. Cut-off was the mean plus four times the standard deviation of optical density (OD) in negative group. One hundred and fifty-seven sera from free-range chicken were investigated. Results showed 58.5% of the chickens were positive with ELISA test; 12.7% had OD over the positive control and may be considered as true infected chickens. The results between the cut-off and the positive control may include infections with low titers of antibodies or may represent serum scar of past infection or may be the result of cross-reaction with other nematodes rather than A. galli which is used for the adsorption of sera. In conclusion, high prevalence of Toxocara sp. antibodies demonstrates natural infection of free-range chickens from Espírito Santo State which may represent a risk of infection with this nematode in people who have the habit of eating raw or undercooked chicken meat or viscera. The results also suggest that chickens may be useful as sentinels to detect soil contaminated with Toxocara eggs.

  9. Natural Occurrence of Entomogenous Nematodes in Tennessee Nursery Soils

    PubMed Central

    Rueda, L. M.; Osawaru, S. O.; Georgi, L. L.; Harrison, R. E.

    1993-01-01

    To isolate potential insect biocontrol agents, entomogenous nematodes were surveyed in Tennessee plant nurseries in 1991. Soil samples from 113 nursery sites were baited with greater wax moth (Galleria mellonella) larvae, house cricket (Acheta domesticus) adults, lesser mealworm (Alphitobius diaperings) adults, and house fly (Musca domestica) larvae. Heterorhabditis bacteriophora and Steinernema carpocapsae were each recovered from 17 soil samples. Heterorhabditis bacteriophora was more common in habitats with crape myrtle (Lagerstroemia indica) and Chinese juniper (Juniperus chinensis) than other nursery plants, and S. carpocapsae was more frequently recovered from habitats with juniper and Southern magnolia (Magnolia grandiflora). Bulk density, electrical conductivity, organic matter, pH, temperature, and moisture content of the entomogenous-nematode positive soil samples were compared. Other nematode genera recovered with insect baits included Rhabditis sp., Pelodera sp., Cryptaphelenchoides sp., and Mesodiplogaster sp., which was recovered from a greater percentage of soil samples than the other five genera. PMID:19279756

  10. Biological control of gastrointestinal parasitic nematodes using Duddingtonia flagrans in sheep under natural conditions in Mexico.

    PubMed

    Mendoza-De Gives, Pedro; Zapata Nieto, Claudia; Hernández, Enrique Liébano; Arellano, María Eugenia López; Rodríguez, David Herrera; Garduño, Roberto González

    2006-10-01

    This investigation was aimed to evaluate the use of an oral bio-preparation containing Duddingtonia flagrans chlamydospores for the control of sheep gastrointestinal parasitic nematodes under the Mexican cold high plateau conditions. Two groups of gastrointestinal parasitic nematode naturally infected sheep, were randomly selected and located into two free-gastrointestinal nematode larvae paddocks. Group 1 received once a week a supplement containing D. flagrans chlamydospores mixed with oats and molasses. Group 2 received a similar supplement without any fungal material. After 5 months grazing animals were discarded from the experiment and two groups of free-nematode "tracer" sheep were located into the same paddocks to collect larvae from the contaminated pastures. Animals were slaughtered and necropsied and the nematodes were obtained and counted. A screening of the number of gastrointestinal nematode larvae present on the grass was performed and compared between the two grazing areas. The results showed 56% reduction in the Ostertagia (Teladorsagia) circumcincta and 94% reduction in the Nematodirus sp. population of the "tracer" sheep who grazed on the D. flagrans-treated sheep area, compared to the nematode population in animals grazed on the non-treated area. The results of the number of larvae on the grazing pastures showed a 51.1% reduction for H. contortus, and 100% for Cooperia sp. in the area with fungi. In the case of Trichostrongylus sp. no reduction was observed, when compared to the control group.

  11. Ecology of plant and free-living nematodes in natural and agricultural soil.

    PubMed

    Neher, Deborah A

    2010-01-01

    Nematodes are aquatic organisms that depend on thin water films to live and move within existing pathways of soil pores of 25-100 mum diameter. Soil nematodes can be a tool for testing ecological hypotheses and understanding biological mechanisms in soil because of their central role in the soil food web and linkage to ecological processes. Ecological succession is one of the most tested community ecology concepts, and a variety of nematode community indices have been proposed for purposes of environmental monitoring. In contrast, theories of biogeography, colonization, optimal foraging, and niche partitioning by nematodes are poorly understood. Ecological hypotheses related to strategies of coexistence of nematode species sharing the same resource have potential uses for more effective biological control and use of organic amendments to foster disease suppression. Essential research is needed on nematodes in natural and agricultural soils to synchronize nutrient release and availability relative to plant needs, to test ecological hypotheses, to apply optimal foraging and niche partitioning strategies for more effective biological control, to blend organic amendments to foster disease suppression, to monitor environmental and restoration status, and to develop better predictive models for land-use decisions.

  12. [The carnivorous fungi hyphomycetes are natural regulators of the size of animal parasitic nematodes].

    PubMed

    Tepliakova, T V; Efremova, E A; Riabchikova, E I

    2005-01-01

    The carnivorous fungi hyphomycetes are natural enemies of soil nematodes. Laboratory tests examining the effect of the effective strain Duddingtonia flagrans T-89 on equine strongyle larvae have indicated that their size can be reduced 5-48-fold under the action of the fungus. Using helminth-infected mice as an example has ascertained that when the animals are fed a biopreparation, the chlamydial spores of the carnivorous fungus D. flagrans remain viable and continue their development in the excrements. The dead nematodes show cell structural impairments in all tissues and organs, which may be associated with the action of the substances contained in the cell envelope of the fungus.

  13. Nuclear receptors in nematode development: Natural experiments made by a phylum.

    PubMed

    Kostrouchova, Marta; Kostrouch, Zdenek

    2015-02-01

    The development of complex multicellular organisms is dependent on regulatory decisions that are necessary for the establishment of specific differentiation and metabolic cellular states. Nuclear receptors (NRs) form a large family of transcription factors that play critical roles in the regulation of development and metabolism of Metazoa. Based on their DNA binding and ligand binding domains, NRs are divided into eight NR subfamilies from which representatives of six subfamilies are present in both deuterostomes and protostomes indicating their early evolutionary origin. In some nematode species, especially in Caenorhabditis, the family of NRs expanded to a large number of genes strikingly exceeding the number of NR genes in vertebrates or insects. Nematode NRs, including the multiplied Caenorhabditis genes, show clear relation to vertebrate and insect homologues belonging to six of the eight main NR subfamilies. This review summarizes advances in research of nematode NRs and their developmental functions. Nematode NRs can reveal evolutionarily conserved mechanisms that regulate specific developmental and metabolic processes as well as new regulatory adaptations. They represent the results of a large number of natural experiments with structural and functional potential of NRs for the evolution of the phylum. The conserved and divergent character of nematode NRs adds a new dimension to our understanding of the general biology of regulation by NRs. This article is part of a Special Issue entitled: Nuclear receptors in animal development.

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

    PubMed

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

    2014-09-17

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

  15. Naturally acquired antibodies against Clostridium perfringens epsilon toxin in goats.

    PubMed

    Veschi, Josir Laine A; Bruzzone, Octavio A; Losada-Eaton, Daniela M; Dutra, Iveraldo S; Fernandez-Miyakawa, Mariano E

    2008-09-15

    Clostridium perfringens type D-producing epsilon toxin is a common cause of death in sheep and goats worldwide. Although anti-epsilon toxin serum antibodies have been detected in healthy non-vaccinated sheep, the information regarding naturally acquired antibodies in ruminants is scanty. The objective of the present report was to characterize the development of naturally acquired antibodies against C. perfringens epsilon toxin in goats. The levels of anti-epsilon toxin antibodies in blood serum of goat kids from two different herds were examined continuously for 14 months. Goats were not vaccinated against any clostridial disease and received heterologous colostrums from cows that were not vaccinated against any clostridial disease. During the survey one of these flocks suffered an unexpectedly severe C. perfringens type D enterotoxemia outbreak. The results showed that natural acquired antibodies against C. perfringens epsilon toxin can appear as early as 6 weeks in young goats and increase with the age without evidence of clinical disease. The enterotoxemia outbreak was coincident with a significant increase in the level of anti-epsilon toxin antibodies.

  16. The Dynamics of Naturally Acquired Immunity to Plasmodium falciparum Infection

    PubMed Central

    Pinkevych, Mykola; Petravic, Janka; Chelimo, Kiprotich; Kazura, James W.; Moormann, Ann M.; Davenport, Miles P.

    2012-01-01

    Severe malaria occurs predominantly in young children and immunity to clinical disease is associated with cumulative exposure in holoendemic settings. The relative contribution of immunity against various stages of the parasite life cycle that results in controlling infection and limiting disease is not well understood. Here we analyse the dynamics of Plasmodium falciparum malaria infection after treatment in a cohort of 197 healthy study participants of different ages in order to model naturally acquired immunity. We find that both delayed time-to-infection and reductions in asymptomatic parasitaemias in older age groups can be explained by immunity that reduces the growth of blood stage as opposed to liver stage parasites. We found that this mechanism would require at least two components – a rapidly acting strain-specific component, as well as a slowly acquired cross-reactive or general immunity to all strains. Analysis and modelling of malaria infection dynamics and naturally acquired immunity with age provides important insights into what mechanisms of immune control may be harnessed by malaria vaccine strategists. PMID:23093922

  17. Localization of Haemophilus ducreyi in naturally acquired chancroidal ulcers.

    PubMed

    Bauer, Margaret E; Townsend, Carisa A; Ronald, Allan R; Spinola, Stanley M

    2006-08-01

    Haemophilus ducreyi causes the sexually transmitted genital ulcer disease chancroid. In human inoculation experiments, bacteria colocalize with neutrophils and macrophages but remain extracellular. The organism also colocalizes with collagen and fibrin but not with keratinocytes, fibroblasts, laminin, or fibronectin. These relationships are established by 48 h postinoculation and persist through the pustular stage of disease. To extend these observations to the ulcerative stage of disease, and to compare results in the human model with those of natural disease, we obtained biopsies from patients with naturally acquired chancroid. All ulcers were culture positive for H. ducreyi and histologically very similar to pustules from the human model. Staining with H. ducreyi-specific monoclonal antibodies demonstrated H. ducreyi within 5 biopsies. The organism was chiefly found within the granulocytic infiltrate of the ulcer. Dual staining for H. ducreyi and eukaryotic tissue components showed that H. ducreyi colocalized with neutrophils and fibrin at the ulcerative stage of disease. No bacteria were associated with keratinocytes, fibroblasts, or collagen. Overall, these findings are consistent with results from the human model. This is the first reported study to localize bacteria specifically identified as H. ducreyi within naturally acquired chancroid.

  18. Anthelmintic efficacy and dose determination of Albizia anthelmintica against gastrointestinal nematodes in naturally infected Ugandan sheep.

    PubMed

    Gradé, J T; Arble, B L; Weladji, R B; Van Damme, P

    2008-11-07

    Weight loss, stunted growth, and death caused by gastrointestinal parasites are major constraints to livestock productivity, especially in tropical and developing countries where regular use, and misuse, of anthelmintics has led to nematode resistance. Albizia anthelmintica Brong. (Fabaceae) is traditionally employed throughout East Africa to treat helminth parasitosis in livestock. Reported efficacy has varied from 90% against mixed nematodes to just 19% against Haemonchus contortus alone. The objective of this study was to assess the anthelmintic effect of A. anthelmintica against naturally occurring infections of mixed gastrointestinal parasites, and to establish an effective treatment dose, in sheep under pastoral field conditions of northern Uganda. A. anthelmintica bark was collected and prepared according to local custom and packed into gel capsules. Fifty-five young female local mixed-breed lambs were randomly assigned to six groups, including a positive control group that received levamisole (synthetic anthelmintic) and a negative control group that received no treatment. Following the World Association for the Advancement of Veterinary Parasitology (WAAVP) dose determination guidelines, the other four groups were treated with varying doses of A. anthelmintica. Statistical analyses (using generalized linear models) were performed to assess treatment effect. There was a significant treatment (group) effect on parasite egg/oocyte counts per gram (EPG) for nematodes, but not for coccidia. The most effective dose against nematodes (0.8g, 58.7mg/kg) closely approximates what is usually given by traditional healers, 0.9g/adult sheep. It provided major and significant reduction in EPG as compared to the negative control. Anthelmintic efficacy was estimated using percent faecal egg count reduction (FECR). Other than the positive control, animals in the standard dose group showed the greatest decline in shedding of nematode eggs, with an FECR of 78%. This study

  19. Phylogenetic Analysis of Entomoparasitic Nematodes, Potential Control Agents of Flea Populations in Natural Foci of Plague

    PubMed Central

    Koshel, E. I.; Aleshin, V. V.; Eroshenko, G. A.; Kutyrev, V. V.

    2014-01-01

    Entomoparasitic nematodes are natural control agents for many insect pests, including fleas that transmit Yersinia pestis, a causative agent of plague, in the natural foci of this extremely dangerous zoonosis. We examined the flea samples from the Volga-Ural natural focus of plague for their infestation with nematodes. Among the six flea species feeding on different rodent hosts (Citellus pygmaeus, Microtus socialis, and Allactaga major), the rate of infestation varied from 0 to 21%. The propagation rate of parasitic nematodes in the haemocoel of infected fleas was very high; in some cases, we observed up to 1,000 juveniles per flea specimen. Our study of morphology, life cycle, and rDNA sequences of these parasites revealed that they belong to three distinct species differing in the host specificity. On SSU and LSU rRNA phylogenies, these species representing three genera (Rubzovinema, Psyllotylenchus, and Spilotylenchus), constitute a monophyletic group close to Allantonema and Parasitylenchus, the type genera of the families Allantonematidae and Parasitylenchidae (Nematoda: Tylenchida). We discuss the SSU-ITS1-5.8S-LSU rDNA phylogeny of the Tylenchida with a special emphasis on the suborder Hexatylina. PMID:24804197

  20. Phylogenetic analysis of entomoparasitic nematodes, potential control agents of flea populations in natural foci of plague.

    PubMed

    Koshel, E I; Aleshin, V V; Eroshenko, G A; Kutyrev, V V

    2014-01-01

    Entomoparasitic nematodes are natural control agents for many insect pests, including fleas that transmit Yersinia pestis, a causative agent of plague, in the natural foci of this extremely dangerous zoonosis. We examined the flea samples from the Volga-Ural natural focus of plague for their infestation with nematodes. Among the six flea species feeding on different rodent hosts (Citellus pygmaeus, Microtus socialis, and Allactaga major), the rate of infestation varied from 0 to 21%. The propagation rate of parasitic nematodes in the haemocoel of infected fleas was very high; in some cases, we observed up to 1,000 juveniles per flea specimen. Our study of morphology, life cycle, and rDNA sequences of these parasites revealed that they belong to three distinct species differing in the host specificity. On SSU and LSU rRNA phylogenies, these species representing three genera (Rubzovinema, Psyllotylenchus, and Spilotylenchus), constitute a monophyletic group close to Allantonema and Parasitylenchus, the type genera of the families Allantonematidae and Parasitylenchidae (Nematoda: Tylenchida). We discuss the SSU-ITS1-5.8S-LSU rDNA phylogeny of the Tylenchida with a special emphasis on the suborder Hexatylina.

  1. Unraveling the intraguild competition between Oscheius spp. nematodes and entomopathogenic nematodes: Implications for their natural distribution in Swiss agricultural soils.

    PubMed

    Campos-Herrera, Raquel; Půža, Vladimir; Jaffuel, Geoffrey; Blanco-Pérez, Rubén; Čepulytė-Rakauskienė, Rasa; Turlings, Ted C J

    2015-11-01

    Entomopathogenic nematodes (EPN) are excellent biological control agents to fight soil-dwelling insect pests. In a previous survey of agricultural soils of Switzerland, we found mixtures of free-living nematodes (FLN) in the genus Oscheius, which appeared to be in intense competition with EPN. As this may have important implications for the long-term persistence of EPN, we studied this intraguild competition in detail. We hypothesized that (i) Oscheius spp. isolates act as scavengers rather than entomopathogens, and (ii) cadavers with relatively small numbers of EPN are highly suitable resources for Oscheius spp. reproduction. To study this, we identified Oscheius spp. isolated from Swiss soils, quantified the outcome of EPN/Oscheius competition in laboratory experiments, developed species-specific primers and probe for quantitative real-time PCR, and evaluated their relative occurrence in the field in the context of the soil food web. Molecular analysis (ITS/D2D3) identified MG-67/MG-69 as Oscheius onirici and MG-68 as O. tipulae (Dolichura-group). Oscheius spp. indeed behaved as scavengers, reproducing in ∼64% of frozen-killed cadavers from controlled experiments. Mixed infection in the laboratory by Oscheius spp. with low (3 IJs) or high (20 IJs) initial EPN numbers revealed simultaneous reproduction in double-exposed cadavers which resulted in a substantial reduction in the number of EPN progeny from the cadaver. This effect depended on the number of EPN in the initial inoculum and differed by EPN species; Heterorhabditis megidis was better at overcoming competition. This study reveals Oscheius spp. as facultative kleptoparasites that compete with EPN for insect cadavers. Using real-time qPCR, we were able to accurately quantify this strong competition between FLN and EPN in cadavers that were recovered after soil baiting (∼86% cadavers with >50% FLN production). The severe competition within the host cadavers and the intense management of the soils in

  2. Diurnal fluctuations in nematode egg excretion in naturally and in experimentally infected chickens.

    PubMed

    Wongrak, Kalyakorn; Gauly, Matthias; Daş, Gürbüz

    2015-03-15

    We investigated whether nematode egg excretion through feces of naturally or experimentally infected chickens follow certain patterns within a day, which may allow determining the most appropriate sampling time for the highest parasite egg concentration. Feces samples (n=864) from chickens (n=36) with naturally occurring mixed nematode infections (trials N1, N2) or with an experimental Ascaridia galli infection (E) were collected quantitatively every 4h for four consecutive days. Number of eggs per gram of feces (EPG) was determined, and accumulative egg output (AEO) at each sampling time as well as total number of eggs excreted within 24h (eggs per day, EPD) were then estimated. At the end of the collection period, the hens were necropsied and their worm burdens determined. Naturally infected hens harbored Heterakis gallinarum (100%), Capillaria spp. (95.7%) and A. galli (91.3%). The experimental A. galli infection produced patent infections in all the birds. In general, both fecal egg concentration (EPG) and the amount of feces increased (P<0.05) sharply from the early morning to early-noon (10:00 a.m.) and remained at a high level until evenings which thereafter decreased to their initial levels during the night both in naturally and experimentally infected birds. This resulted in a more apparent increase or a decrease in AEO at the corresponding time points, respectively, and led to much higher egg excretions during the daytime than the nights. Despite the apparent within day fluctuations in egg excretion, neither EPG (P=0.704) nor AEO (P=0.499) nor EPD (P=0.149) was significantly different among the four collection days. Similarly, there was no significant interaction (P>0.05) between effects of sampling hours and days on EPG and AEO, suggesting the existence of repeatable diurnal fluctuations within each day. Although an association between climatic parameters (e.g., ambient temperature and relative humidity) and the nematode egg excretion was quantified, a

  3. Immunogenicity of bioactive magnetic nanoparticles: natural and acquired antibodies.

    PubMed

    Ziv, Ofra; Avtalion, Ramy R; Margel, Shlomo

    2008-06-15

    Uniform magnetic nanoparticles (MNP) were prepared by nucleation followed by controlled growth of maghemite thin films onto porcine gelatin nuclei. The formed gelatin containing MNP (Gel-MNP) were then coated with dextran (Gel-MNP-Dex) followed by human serum albumin (Gel-MNP-Dex-HSA). Since these MNP are designated for clinical applications, studies concerning the immunogenicity of their antigenic components (porcine gelatin, dextran, and HSA) have been performed in BALB-C mice. These studies demonstrated that plasma of nonimmunized mice already contains basal levels of natural antibodies against all of these antigenic components. This work also demonstrated that the conjugated gelatin is a weak immunogen: Intraperitoneal injection of the various MNP (Gel-MNP, Gel-MNP-Dex dispersed in PBS emulsified with Incomplete Freund's Adjuvant (IFA) mineral oil and Gel-MNP-Dex-HSA dispersed in PBS) did not increase significantly the acquired anti-gelatin antibody titers. Exceptional behavior was observed following immunization with Gel-MNP-Dex-HSA dispersed in PBS emulsified with IFA, which exhibited an adjuvant effect and turned gelatin into a stronger immunogen. In contrast to gelatin, the conjugated HSA and dextran were found to be strong immunogens. The possibility that the various MNP will not induce an autoimmune response as a result of their clinical use is discussed in the contest of the protective role of the natural antibodies.

  4. A case report of inhalation anthrax acquired naturally.

    PubMed

    Azarkar, Zohreh; Bidaki, Majid Zare

    2016-03-03

    Anthrax is a zoonotic occupational disease caused by Bacillus anthracis, a rod-shaped immobile aerobic gram-positive bacteria with spore. Anthrax occurs in humans randomly and with low frequency. Most cases of anthrax are acquired through contact with infected animals or contaminated animal products. This old disease became particularly important since 2001 that the biological spores were exploited in America. Depending on the transmission method of the disease, clinical manifestations occur in three classes: Cutaneous, respiratory, and gastrointestinal anthrax. The respiratory form is considered as the most fatal and a rare form of anthrax intending to show complicated and unusual manifestations. In this case report a rare case of inhalation anthrax acquired naturally in southeast of Iran is presented. A blind 65-year-old man, living in a rural area, was admitted with respiratory infection, fever, dyspnea, loss of appetite, and myalgia. The patient was treated with outpatient antibiotics a week ago. After admission, the patient was again treated for pneumonia, but there was no improvement despite treatment and the patient was suffering from septicemia symptoms. Radiographic images showed wide mediastinum. Bacillus anthracis was isolated from blood and sputum culture and the results were confirmed by colony morphology, biochemical reactions and PCR. The treatment was changed to ciprofloxacin, clindamycin, and penicillin. On the second day of anthrax treatment, the patient was complicated with jaundice, elevation of liver enzymes, and a significant drop in hemoglobin, hematocrit, and platelet despite lack of obvious bleeding and was complicated with respiratory distress and sepsis and died a week after treatment. We could discover no specific exposure associated with anthrax infection for this patient. However, due to being located in an endemic and enzootic area, it is proposed that the exposure occurred through contact with infected airborne dust or an unknown

  5. Isolation of naturally associated bacteria of necromenic Pristionchus nematodes and fitness consequences.

    PubMed

    Rae, Robbie; Riebesell, Metta; Dinkelacker, Iris; Wang, Qiong; Herrmann, Matthias; Weller, Andreas M; Dieterich, Christoph; Sommer, Ralf J

    2008-06-01

    Nematodes and bacteria are major components of the soil ecosystem. Many nematodes use bacteria for food, whereas others evolved specialized bacterial interactions ranging from mutualism to parasitism. Little is known about the biological mechanisms by which nematode-bacterial interactions are achieved, largely because in the laboratory nematodes are often cultured under artificial conditions. We investigated the bacterial interactions of nematodes from the genus Pristionchus that have a strong association with scarab beetles. Pristionchus has a different feeding strategy than Caenorhabditis and meta-genomic 16S sequence analysis of Pristionchus individuals showed a diversity of living bacteria within the nematode gut and on the nematode cuticle. Twenty-three different bacterial strains were isolated from three Pristionchus-beetle associations and were used to study nematode-bacterial interactions under controlled laboratory conditions. We show a continuum of bacterial interactions from dissemination, to reduction in brood size and nematode mortality caused by bacteria derived from insect hosts. Olfactory discrimination experiments show distinct chemoattraction and fitness profiles of Pristionchus nematodes when exposed to different bacteria. For example, Pristionchus pacificus avoids Serratia marcescens possibly because of pathogenicity. Also, P. pacificus avoids Bacillus thuringiensis and insect pathogenic bacteria but is resistant to the human pathogens Staphylococcus aureus and Pseudomonas aeruginosa, unlike Caenorhabditis elegans. Pristionchus specifically recognize and respond to bacteria that cause ill health. Bringing the nematode-bacterial interaction into the laboratory allows detailed functional studies, including the genetic manipulation of the interaction in both nematodes and bacteria.

  6. Natural and experimental infection of Caenorhabditis nematodes by novel viruses related to nodaviruses.

    PubMed

    Félix, Marie-Anne; Ashe, Alyson; Piffaretti, Joséphine; Wu, Guang; Nuez, Isabelle; Bélicard, Tony; Jiang, Yanfang; Zhao, Guoyan; Franz, Carl J; Goldstein, Leonard D; Sanroman, Mabel; Miska, Eric A; Wang, David

    2011-01-25

    An ideal model system to study antiviral immunity and host-pathogen co-evolution would combine a genetically tractable small animal with a virus capable of naturally infecting the host organism. The use of C. elegans as a model to define host-viral interactions has been limited by the lack of viruses known to infect nematodes. From wild isolates of C. elegans and C. briggsae with unusual morphological phenotypes in intestinal cells, we identified two novel RNA viruses distantly related to known nodaviruses, one infecting specifically C. elegans (Orsay virus), the other C. briggsae (Santeuil virus). Bleaching of embryos cured infected cultures demonstrating that the viruses are neither stably integrated in the host genome nor transmitted vertically. 0.2 µm filtrates of the infected cultures could infect cured animals. Infected animals continuously maintained viral infection for 6 mo (∼50 generations), demonstrating that natural cycles of horizontal virus transmission were faithfully recapitulated in laboratory culture. In addition to infecting the natural C. elegans isolate, Orsay virus readily infected laboratory C. elegans mutants defective in RNAi and yielded higher levels of viral RNA and infection symptoms as compared to infection of the corresponding wild-type N2 strain. These results demonstrated a clear role for RNAi in the defense against this virus. Furthermore, different wild C. elegans isolates displayed differential susceptibility to infection by Orsay virus, thereby affording genetic approaches to defining antiviral loci. This discovery establishes a bona fide viral infection system to explore the natural ecology of nematodes, host-pathogen co-evolution, the evolution of small RNA responses, and innate antiviral mechanisms.

  7. Natural and Experimental Infection of Caenorhabditis Nematodes by Novel Viruses Related to Nodaviruses

    PubMed Central

    Wu, Guang; Nuez, Isabelle; Bélicard, Tony; Jiang, Yanfang; Zhao, Guoyan; Franz, Carl J.; Goldstein, Leonard D.; Sanroman, Mabel; Miska, Eric A.; Wang, David

    2011-01-01

    An ideal model system to study antiviral immunity and host-pathogen co-evolution would combine a genetically tractable small animal with a virus capable of naturally infecting the host organism. The use of C. elegans as a model to define host-viral interactions has been limited by the lack of viruses known to infect nematodes. From wild isolates of C. elegans and C. briggsae with unusual morphological phenotypes in intestinal cells, we identified two novel RNA viruses distantly related to known nodaviruses, one infecting specifically C. elegans (Orsay virus), the other C. briggsae (Santeuil virus). Bleaching of embryos cured infected cultures demonstrating that the viruses are neither stably integrated in the host genome nor transmitted vertically. 0.2 µm filtrates of the infected cultures could infect cured animals. Infected animals continuously maintained viral infection for 6 mo (∼50 generations), demonstrating that natural cycles of horizontal virus transmission were faithfully recapitulated in laboratory culture. In addition to infecting the natural C. elegans isolate, Orsay virus readily infected laboratory C. elegans mutants defective in RNAi and yielded higher levels of viral RNA and infection symptoms as compared to infection of the corresponding wild-type N2 strain. These results demonstrated a clear role for RNAi in the defense against this virus. Furthermore, different wild C. elegans isolates displayed differential susceptibility to infection by Orsay virus, thereby affording genetic approaches to defining antiviral loci. This discovery establishes a bona fide viral infection system to explore the natural ecology of nematodes, host-pathogen co-evolution, the evolution of small RNA responses, and innate antiviral mechanisms. PMID:21283608

  8. Movement of Five Nematode Species through Sand Subjected to Natural Temperature Gradient Fluctuations

    PubMed Central

    Robinson, A. F.

    1994-01-01

    Temperature gradient fluctuations that occur naturally as a result of heating and cooling of the soil surface were reproduced within 15-cm-d, 15-cm-long acrylic tubes filled with moist sand. Sunny and rainy periods during the late summer in eastern Texas were simulated. Five ecologically different nematode species were adapted to fluctuating temperatures for 20-36 hours at a simulated depth of 12.5 cm before being injected simultaneously into the centers of tubes at that depth. When heat waves were propagated horizontally to eliminate gravitational effects, the movement of Ditylenchus phyllobius, Steinernema glaseri, and Heterorhabditis bacteriophora relative to the thermal surface was rapid and largely random. However, Rotylenchulus reniformis moved away from and Meloidogyne incognita moved toward the thermal surface. When heat waves were propagated upward or downward, responses to temperature were the same as when propagated horizontally, irrespective of gravity. The initial direction of movement 1.5 hours after introduction to 20-era-long tubes at five depths at five intervals within a 24-hour cycle indicated that M. incognita moved away from and R. reniformis moved toward the temperature to which last exposed. Differences in movement of the five species tested relative to gravity appeared related to body length, with the smallest nematodes moving downward and the largest moving upward. PMID:19279868

  9. Competition and intraguild predation between the braconid parasitoid Bracon hylobii and the entomopathogenic nematode Heterorhabditis downesi, natural enemies of the large pine weevil, Hylobius abietis.

    PubMed

    Everard, A; Griffin, C T; Dillon, A B

    2009-04-01

    In biological control programmes introduced natural enemies compete with indigenous enemies for hosts and may also engage in intraguild predation when two species competing for the same prey attack and consume one another. The large pine weevil, Hylobius abietis L. (Coleoptera: Curculionidae), is an important pest of coniferous reforestation in Europe. Among its natural enemies, the parasitoid Bracon hylobii Ratz. (Hymenoptera: Braconidae) and entomopathogenic nematodes have potential as biological control agents. Both parasitoid and nematodes target the weevil larvae and, hence, there is potential for competition or intraguild predation.In this study, we examine the interaction of B. hylobii with the nematode Heterorhabditis downesi Stock, Griffin and Burnell (Nematode: Heterorhabditidae), testing the susceptibility of larvae, pupae and adults of B. hylobii to H. downesi and whether female parasitoids discriminate between nematode-infected and uninfected weevils for oviposition. In choice tests, when weevils were exposed to nematodes 1-7 days previously, no B. hylobii oviposited on nematode-infected weevil larvae. Up to 24 h, healthy weevils were twice as likely as nematode-infected ones to be used for oviposition. Bracon hylobii females did not adjust clutch size; nematode-infected hosts were either rejected or the parasitoid laid a full clutch of eggs on them.When nematodes were applied to the parasitoid feeding on weevil larvae, the nematodes parasitized the parasitoid larvae, there was a reduction in cocoon formation and fewer cocoons eclosed. Eclosion rate was not reduced when nematodes were applied to fully formed cocoons, but nearly all of the emerging adults were killed by nematodes.

  10. Natural population dynamics of entomopathogenic nematode Steinernema affine (Steinernematidae) under dry conditions: Possible nematode persistence within host cadavers?

    PubMed

    Půza, Vladimír; Mrácek, Zdenek

    2007-09-01

    The effect of dry conditions on the population dynamics of the entomopathogenic nematode (EPN) Steinernema affine was studied for one month in the exceptionally dry period in the summer of 2003 in the oak wood in the vicinity of Ceské Budejovice, Czech Republic. Soil moisture, soil temperature, and the abundance of suitable insect hosts were monitored. The abundance of infective juveniles (IJs) was correlated with soil moisture and both these values were gradually decreasing during the study period and finally rapidly increased at the end of the investigation. During this period there was a decline in the number of insects suitable as hosts for S. affine, but not in numbers of unsuitable insects. We hypothesise that the observed decrease in IJ numbers was probably caused by the persistence of IJs in host cadavers due to low ambient moisture.

  11. A Bias for the Natural? Children's Beliefs about Traits Acquired through Effort, Bribes, or Medicine

    ERIC Educational Resources Information Center

    Lockhart, Kristi L.; Keil, Frank C.; Aw, Justine

    2013-01-01

    Three studies compared beliefs about natural and late blooming positive traits with those acquired through personal effort, extrinsic rewards or medicine. Young children (5-6 years), older children (8-13 years), and adults all showed a strong bias for natural and late blooming traits over acquired traits. All age groups, except 8- to 10-year-olds,…

  12. A Bias for the Natural? Children's Beliefs about Traits Acquired through Effort, Bribes, or Medicine

    ERIC Educational Resources Information Center

    Lockhart, Kristi L.; Keil, Frank C.; Aw, Justine

    2013-01-01

    Three studies compared beliefs about natural and late blooming positive traits with those acquired through personal effort, extrinsic rewards or medicine. Young children (5-6 years), older children (8-13 years), and adults all showed a strong bias for natural and late blooming traits over acquired traits. All age groups, except 8- to 10-year-olds,…

  13. Efficacy of a single high oxfendazole dose against gastrointestinal nematodes in naturally infected pigs.

    PubMed

    Alvarez, Luis; Saumell, Carlos; Fusé, Luis; Moreno, Laura; Ceballos, Laura; Domingue, Gilbert; Donadeu, Meritxell; Dungu, Baptiste; Lanusse, Carlos

    2013-05-01

    The goal of the current experiment was to assess the clinical efficacy of oxfendazole (OFZ) administered as a single oral dose (30 mg/kg) to pigs naturally parasitized with Ascaris suum, Oesophagostomum spp., Metastrongylus spp. and Trichuris suis. Thirty-six local ecotype piglets were divided into three independent experiments, named I, II and III (n=12 each), respectively. Each experiment involved two different groups (n=6): Untreated Control and OFZ treated. Animals were naturally parasitized with A. suum (Experiments I, II and III), Oesophagostomum spp. (Experiments I and II), T. suis (Experiments II and III) and Metastrongylus spp. (Experiment I). Pigs in the treated group received OFZ (Synanthic(®), Merial Ltd., 9.06% suspension) orally at 30 mg/kg dose. At five (5) days post-treatment, animals were sacrificed and the clinical efficacy of the OFZ treatment was established following the currently available WAAVP guidelines for a controlled efficacy test. None of the animals involved in this experiment showed any adverse events during the study. OFZ treatment given as a single 30 mg/kg oral dose showed a 100% efficacy against all the nematode parasites present in the three experiments. In conclusion, under the current experimental conditions, OFZ orally administered to naturally parasitized piglets at a single dose of 30 mg/kg was safe and highly efficacious (100%) against adult stages of A. suum, Oesophagostomum spp., T. suis and Metastrongylus spp.

  14. Variation in Base-Substitution Mutation in Experimental and Natural Lineages of Caenorhabditis Nematodes

    PubMed Central

    Denver, Dee R.; Wilhelm, Larry J.; Howe, Dana K.; Gafner, Kristin; Dolan, Peter C.; Baer, Charles F.

    2012-01-01

    Variation among lineages in the mutation process has the potential to impact diverse biological processes ranging from susceptibilities to genetic disease to the mode and tempo of molecular evolution. The combination of high-throughput DNA sequencing (HTS) with mutation-accumulation (MA) experiments has provided a powerful approach to genome-wide mutation analysis, though insights into mutational variation have been limited by the vast evolutionary distances among the few species analyzed. We performed a HTS analysis of MA lines derived from four Caenorhabditis nematode natural genotypes: C. elegans N2 and PB306 and C. briggsae HK104 and PB800. Total mutation rates did not differ among the four sets of MA lines. A mutational bias toward G:C→A:T transitions and G:C→T:A transversions was observed in all four sets of MA lines. Chromosome-specific rates were mostly stable, though there was some evidence for a slightly elevated X chromosome mutation rate in PB306. Rates were homogeneous among functional coding sequence types and across autosomal cores, arms, and tips. Mutation spectra were similar among the four MA line sets but differed significantly when compared with patterns of natural base-substitution polymorphism for 13/14 comparisons performed. Our findings show that base-substitution mutation processes in these closely related animal lineages are mostly stable but differ from natural polymorphism patterns in these two species. PMID:22436997

  15. Natural genetic and induced plant resistance, as a control strategy to plant-parasitic nematodes alternative to pesticides.

    PubMed

    Molinari, Sergio

    2011-03-01

    Plant-parasitic nematodes are pests of a wide range of economically important crops, causing severe losses to agriculture. Natural genetic resistance of plants is expected to be a valid solution of the many problems nematodes cause all over the world. Progress in resistance applications is particularly important for the less-developed countries of tropical and subtropical regions, since use of resistant cultivars may be the only possible and economically feasible control strategy in those farming systems. Resistance is being considered of particular importance also in modern high-input production systems of developed countries, as the customary reliance on chemical nematicides has been restricted or has come to an end. This review briefly describes the genetic bases of resistance to nematodes in plants and focuses on the chances and problems of its exploitation as a key element in an integrated management program. Much space is dedicated to the major problem of resistance durability, in that the intensive use of resistant cultivars is likely to increasingly induce the selection of virulent populations able to "break" the resistance. Protocols of pest-host suitability are described, as bioassays are being used to evaluate local nematode populations in their potential to be selected on resistant germplasm and endanger resistant crops. The recent progress in using robust and durable resistances against nematodes as an efficient method for growers in vegetable cropping systems is reported, as well as the possible use of chemicals that do not show any unfavorable impact on environment, to induce in plants resistance against plant-parasitic nematodes.

  16. Acquiring Literacy is Natural: Who Skilled Cock Robin?

    ERIC Educational Resources Information Center

    Goodman, Kenneth S.

    1977-01-01

    Ability to read depends less upon learning isolated, sequential skills than upon the natural desire to communicate beyond the oral level and the opportunities offered by society and environment to develop this ability. (JD)

  17. A bias for the natural? Children's beliefs about traits acquired through effort, bribes, or medicine.

    PubMed

    Lockhart, Kristi L; Keil, Frank C; Aw, Justine

    2013-09-01

    Three studies compared beliefs about natural and late blooming positive traits with those acquired through personal effort, extrinsic rewards or medicine. Young children (5-6 years), older children (8-13 years), and adults all showed a strong bias for natural and late blooming traits over acquired traits. All age groups, except 8- to 10-year-olds, treated natural and late-blooming traits as fixed essences that would persist over time and under challenging conditions. Older children and adults viewed traits acquired by intrinsic effort as more similar to natural and late-blooming traits than those acquired through bribes or medicine, suggesting that intrinsic effort itself comes to be seen as a more natural mechanism of change. A bias for the natural may therefore be an early emerging way of evaluating others that is reinforced by the ambient culture and becomes stronger with increasing age. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  18. Host age as a determinant of naturally acquired immunity to Plasmodium falciparum.

    PubMed

    Baird, J K

    1995-03-01

    The usual course of infection by Plasmodium falciparum among adults who lack a history of exposure to endemic malaria is fulminant. The infection in adults living with hyper- to holoendemic malaria is chronic and benign. Naturally acquired immunity to falciparum malaria is the basis of this difference. Confusion surrounds an essential question regarding this process: What is its rate of onset? Opinions vary because of disagreement over the relationships between exposure to infection, antigenic polymorphism and naturally acquired immunity. In this review, Kevin Baird discusses these relationships against a backdrop of host age as a determinant of naturally acquired immunity to falciparum malaria.

  19. In vivo anthelmintic activity of Anogeissus leiocarpus Guill & Perr (Combretaceae) against nematodes in naturally infected sheep.

    PubMed

    Soro, Dramane; Koné, Witabouna Mamidou; Bonfoh, Bassirou; Dro, Bernadin; Toily, Kassédo Bénédicte; Kamanzi, Kagoyire

    2013-07-01

    The identification of new anthelmintic drugs becomes a priority because of the availability of a handful of drugs, cost of treatments, and recent emergence of drug resistance. Medicinal plants are a good source of bioactive compounds for development of drugs. In this study, in vivo efficacy of Anogeissus leiocarpus was assessed in sheep naturally infected with gastrointestinal nematodes. Fecal examination, serological analyses, and necropsy were carried out to determine the egg and worm-burden reduction. The administration of ethanolic extract (single oral dose of 80 mg/kg) of A. leiocarpus induced a moderate fecal egg reduction (81 %) and adult worm-burden reduction (87 %) against Haemonchus contortus and Trichostrongylus colubriformis (82 %). The plant exhibited high efficacy against adult Strongyloïdes papillosus (100 %), Gaigeria pachyscelis (90 %), Cooperia curticei (100 %), and Oesophagostomum columbianum (95 %) but low efficacy against Trichostrongylus axei (67 %) and Trichuris globulosa (79 %). All these helminthes were sensitive to fenbendazole, except O. columbianum which showed a decrease susceptibility (17 %). The plant extract also improved certain biological parameters by increasing bodyweight from 0.7 ± 2.9 to 3.3 ± 1.9 % and improving hematocrit of 6.9 ± 1.6 % 3-week posttreatment. It emerges from the results that the plant possesses significant effectiveness on diarrhea; all treated animals gave normal feces. This study has shown that A. leiocarpus could find an application in the control of multiparasitism in small ruminants.

  20. Assessing resistance of ivermectin and moxidectin against nematodes in cattle naturally infected using three different methodologies.

    PubMed

    Lopes, Welber Daniel Zanetti; Teixeira, Weslen Fabricio Pires; Felippelli, Gustavo; Cruz, Breno Cayeiro; Maciel, Willian Giquelin; Soares, Vando Edésio; dos Santos, Thais Rabelo; de Matos, Lucas Vinicius Shigaki; Fávero, Flávia Carolina; da Costa, Alvimar José

    2014-02-01

    The objective of this study was to evaluate the accuracy of the faecal egg count reduction test (FECRT) and the faecal egg count efficacy test (FECET) to assess the resistance status of ivermectin (630 μg/kg) and moxidectin (200 μg/kg), using the controlled efficacy test as a reference, and whether the results of the EPG are equivalent to the efficacy results from the parasitological necropsies. Two experiments were conducted. The results demonstrate that it was not possible to demonstrate that the EPG values were equivalent with the ivermectin and moxidectin efficacy obtained by parasitological necropsies, mainly if the phenomenon of parasites resistance is not advanced in a determined field population. Maybe the FECET technique would be possibly better than the FECRT. The high anthelmintic efficacy of 200 μg/kg moxidectin, in naturally infected cattle, against field population of nematodes that are resistant to 630 μg/kg ivermectin, was observed in this study. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Biological Effect of Leaf Aqueous Extract of Caesalpinia pyramidalis in Goats Naturally Infected with Gastrointestinal Nematodes

    PubMed Central

    Borges-dos-Santos, Roberto Robson; López, Jorge A.; Santos, Luciano C.; Zacharias, Farouk; David, Jorge Maurício; David, Juceni Pereira; Lima, Fernanda Washington de Mendonça

    2012-01-01

    Forty-eight goats naturally infected with gastrointestinal nematodes were randomly divided into four groups (n = 12): negative control (G1) (untreated), positive control (G2) (treated with doramectin, 1 mL/50 Kg b.w.), and G3 and G4 treated with 2.5 and 5 mg/Kg b.w. of a leaf aqueous extract of Caesalpinia pyramidalis (CP). Fecal and blood samples were regularly collected for the evaluation of fecal egg count (FEC), hematological and immunological parameters to assess the anthelmintic activity. In treated animals with CP, there was noted a significant reduction of 54.6 and 71.2% in the mean FEC (P < 0.05). An increase in IgA levels was observed in G3 and G4 (P < 0.05), during the experimental period, suggesting that it was stimulated by the extract administration. In conclusion, the results showed that CP provoked a protective response in infected animals treated with them. This response could be partly explained by the CP chemical composition. PMID:22548117

  2. Genetic resistance of Barbari and Jamunapari kids to natural infection with gastrointestinal nematodes.

    PubMed

    Chauhan, K K; Rout, P K; Singh, P K; Mandal, A; Singh, S K; Roy, R

    2003-10-01

    An investigation was made in 252 Barbari and Jamunapari kids to assess their resistance to natural infection with gastrointestinal (GI) nematodes and to establish indicator traits for such resistance in Indian goats. The indicator traits, faecal egg counts (FEC) and packed cell volume (PCV) were affected by various genetic and non-genetic factors. There were no breed differences in the FEC or PCV at 3, 6 or 9 months of age. Jamunapari male kids had a higher FEC than the female kids at 6 months of age. However, Barbari female kids had a higher FEC than the respective male kids at 9 months of age. At 6 months of age in both breeds, the kids born in the spring (March-April) had a higher FEC than those born in the autumn (October-November). The FEC of kids at 9 months of age was higher than at 3 or 6 months of age. Sire had a significant effect on PCV at 6 and 9 months of age. The kids born in the autumn had a higher PCV than those born in the spring. The PCV of male Barbari kids differed significantly from that of female kids at all the ages. The correlation coefficient of FEC on both body weight and body weight gain was negative, and there was a loss of body weight in the individuals with a high FEC.

  3. Naturally Acquired Rabies Virus Infections in Wild-Caught Bats

    PubMed Central

    Gordy, Paul; Rudd, Robert; Jarvis, Jodie A.; Bowen, Richard A.

    2012-01-01

    Abstract The study of a zoonotic disease requires an understanding of the disease incidence in animal reservoirs. Rabies incidence in bats submitted to diagnostic laboratories does not accurately reflect the true incidence in wild bat populations as a bias exists for testing bats that have been in contact with humans or pets. This article details the rabies incidence in two species of bats collected from natural settings without such bias. In this study, brain smears from 0.6% and 2.5% of wild-caught and apparently healthy Tadarida brasiliensis and Eptesicus fuscus, respectively, were positive for rabies virus (RV) antigen. Conversely, 92% of the grounded T. brasiliensis were positive for RV. Serology performed on captive colony and sick bats reveal an immune response to rabies. This work illustrates the complex interplay between immunity, disease state, and the conundrum of RV maintenance in bats. PMID:21923271

  4. Consensus on the Development of Vaccines against Naturally Acquired Melioidosis

    PubMed Central

    Funnell, Simon G.P.; Torres, Alfredo G.; Morici, Lisa A.; Brett, Paul J.; Dunachie, Susanna; Atkins, Timothy; Altmann, Daniel M.; Bancroft, Gregory; Peacock, Sharon J.

    2015-01-01

    Several candidates for a vaccine against Burkholderia pseudomallei, the causal bacterium of melioidosis, have been developed, and a rational approach is now needed to select and advance candidates for testing in relevant nonhuman primate models and in human clinical trials. Development of such a vaccine was the topic of a meeting in the United Kingdom in March 2014 attended by international candidate vaccine developers, researchers, and government health officials. The focus of the meeting was advancement of vaccines for prevention of natural infection, rather than for protection from the organism’s known potential for use as a biological weapon. A direct comparison of candidate vaccines in well-characterized mouse models was proposed. Knowledge gaps requiring further research were identified. Recommendations were made to accelerate the development of an effective vaccine against melioidosis. PMID:25992835

  5. Naturally acquired rabies virus infections in wild-caught bats.

    PubMed

    Davis, April; Gordy, Paul; Rudd, Robert; Jarvis, Jodie A; Bowen, Richard A

    2012-01-01

    The study of a zoonotic disease requires an understanding of the disease incidence in animal reservoirs. Rabies incidence in bats submitted to diagnostic laboratories does not accurately reflect the true incidence in wild bat populations as a bias exists for testing bats that have been in contact with humans or pets. This article details the rabies incidence in two species of bats collected from natural settings without such bias. In this study, brain smears from 0.6% and 2.5% of wild-caught and apparently healthy Tadarida brasiliensis and Eptesicus fuscus, respectively, were positive for rabies virus (RV) antigen. Conversely, 92% of the grounded T. brasiliensis were positive for RV. Serology performed on captive colony and sick bats reveal an immune response to rabies. This work illustrates the complex interplay between immunity, disease state, and the conundrum of RV maintenance in bats.

  6. [The effect of dehelminthizations performed during the year on the seasonal dynamics of natural nematode infections in sheep].

    PubMed

    Kozdon, O; Zajícek, D

    1976-11-01

    In four sheep flocks of two age categories dynamics of natural infections by pulmonary and gastrointestinal nematodes was studied; sheep were kept on a farm in Western Bohemia. Dehelminthizations were performed in different intervals during the grazing period on the basis of the results of quantitative coprologic examinations. Total effectiveness of 80--100% intenseffectiveness (IE) was obtained as a result of single peroral or intraruminal dehelminthization with the following preparations: pyrantel hydrochloricum (Spofa), helmatac (SKF) and nilverm (ICI); the effectiveness concerned gastrointestinal nematodes of the genus Haemonchus, Cooperia, Ostertagia, Trichostrongylus, Bunostomum, Chabertia, Nematodirus, Strongyloides, Oesophagostomum and Trichocephalus. The effectiveness of nilverm on lungworms of D. filaria and P. kochi reached 100%; the preparation was less effective and ineffective on M. capillaris. Dehelminthization practices during three years were more successful as to lowering of incidence of lungworm infections of D. filaria and P. kochi than in gastrointestinal nematodes. If sping dehelminthizations had been postponed till the second half of May or June, the climax of the elimination of ova from summer re-infection was put off till November, with an initial significant increase in September. The third dehelminthization, applied in August, did not result in the increased elimination of ova in autumn, while there was no usual autumnal climax following September dehelminthization. Effective dehelminthization performed at the end of November in all three years maintained low levels of infections during winter housing and significantly influenced the health conditions of ewes before lambing. Dynamics of the elimination of ova after dehelminthization was affected by nematodes with the migration phase in organs and tissues -- S. papillosus, Oesophagostomum sp. and Ostertagia sp.; the same effect was observed, during pasture, in nematodes with relatively

  7. Genome-wide variations in a natural isolate of the nematode Caenorhabditis elegans

    PubMed Central

    2014-01-01

    Background Increasing genetic and phenotypic differences found among natural isolates of C. elegans have encouraged researchers to explore the natural variation of this nematode species. Results Here we report on the identification of genomic differences between the reference strain N2 and the Hawaiian strain CB4856, one of the most genetically distant strains from N2. To identify both small- and large-scale genomic variations (GVs), we have sequenced the CB4856 genome using both Roche 454 (~400 bps single reads) and Illumina GA DNA sequencing methods (101 bps paired-end reads). Compared to previously described variants (available in WormBase), our effort uncovered twice as many single nucleotide variants (SNVs) and increased the number of small InDels almost 20-fold. Moreover, we identified and validated large insertions, most of which range from 150 bps to 1.2 kb in length in the CB4856 strain. Identified GVs had a widespread impact on protein-coding sequences, including 585 single-copy genes that have associated severe phenotypes of reduced viability in RNAi and genetics studies. Sixty of these genes are homologs of human genes associated with diseases. Furthermore, our work confirms previously identified GVs associated with differences in behavioural and biological traits between the N2 and CB4856 strains. Conclusions The identified GVs provide a rich resource for future studies that aim to explain the genetic basis for other trait differences between the N2 and CB4856 strains. PMID:24694239

  8. Variability in the intensity of nematode larvae from gastrointestinal tissues of a natural herbivore.

    PubMed

    van Kuren, Andrew T; Boag, Brian; Hruban, Emilie; Cattadori, Isabella M

    2013-04-01

    The migration of infective nematode larvae into the tissues of their hosts has been proposed as a mechanism of reducing larval mortality and increase parasite lifetime reproductive success. Given that individual hosts differ in the level of exposure, strength of immune response and physiological conditions we may expect the number of larvae in tissue to vary both between and within hosts. We used 2 gastrointestinal nematode species common in the European rabbit (Oryctolagus cuniculus) and examined how the number of larvae in the tissue changed with the immune response, parasite intensity-dependent constraints in the lumen and seasonal weather factors, in rabbits of different age, sex and breeding status. For both nematode species, larvae from the gastrointestinal tissue exhibited strong seasonal and host age-related patterns with fewer larvae recovered in summer compared to winter and more in adults than in juveniles. The number of larvae of the 2 nematodes was positively associated with intensity of parasite infection in the lumen and antibody responses while it was negatively related with air temperature and rainfall. Host sex, reproductive status and co-infection with the second parasite species contributed to increase variability between hosts. We concluded that heterogeneities in host conditions are a significant cause of variability of larval abundance in the gastrointestinal tissues. These findings can have important consequences for the dynamics of nematode infections and how parasite's life-history strategies adjust to host changes.

  9. Markers/parameters for the evaluation of natural resistance status of small ruminants against gastrointestinal nematodes.

    PubMed

    Saddiqi, H A; Sarwar, M; Iqbal, Z; Nisa, M; Shahzad, M A

    2012-06-01

    The high prevalence of anthelmintic-resistant gastrointestinal nematodes (GINs) throughout the world has led to the need for alternative worm control strategies. One of the possible substitutes to reduce the problems of drug resistance and residue is the evaluation/breeding of small ruminants for greater resistance to the GINs (organically produced), which in turn would be a helpful tool to predict the performance of an animal. At present, the existing diversity in the genetic potential to resist/tolerate GINs infection both within and between breeds has been validated. Successful selection of animals to define the genotype and identified resistance is related to the employed markers. A number of phenotypic traits such as faecal egg count (FEC), worm burden, serum antibodies, peripheral eosinophilia, packed cell volume, live weight, serum protein and albumin concentrations have been used for this purpose both in natural and artificial infections. Relatively resistant/tolerant animals have also been found to have mastocytosis, globule leucocytes, high levels of histamine and immunoglobulin (Ig) A and IgE concentrations. Of these traits, the principal and most practical measurement used to assess resistance status in animals undergoing similar parasite challenges is FEC. FEC has a positive/negative correlation with other biochemical, cellular and immunological parameters; however, the reliability of individual trial is often questioned and valuable information regarding the genetic makeup can be obtained from pooled data of a large number of trials and parameters. This paper covers all the aspects reported in the literature on various parameters considered to evaluate the resistance status of a range of small ruminant breeds.

  10. Natural selection on individual variation in tolerance of gastrointestinal nematode infection.

    PubMed

    Hayward, Adam D; Nussey, Daniel H; Wilson, Alastair J; Berenos, Camillo; Pilkington, Jill G; Watt, Kathryn A; Pemberton, Josephine M; Graham, Andrea L

    2014-07-01

    Hosts may mitigate the impact of parasites by two broad strategies: resistance, which limits parasite burden, and tolerance, which limits the fitness or health cost of increasing parasite burden. The degree and causes of variation in both resistance and tolerance are expected to influence host-parasite evolutionary and epidemiological dynamics and inform disease management, yet very little empirical work has addressed tolerance in wild vertebrates. Here, we applied random regression models to longitudinal data from an unmanaged population of Soay sheep to estimate individual tolerance, defined as the rate of decline in body weight with increasing burden of highly prevalent gastrointestinal nematode parasites. On average, individuals lost weight as parasite burden increased, but whereas some lost weight slowly as burden increased (exhibiting high tolerance), other individuals lost weight significantly more rapidly (exhibiting low tolerance). We then investigated associations between tolerance and fitness using selection gradients that accounted for selection on correlated traits, including body weight. We found evidence for positive phenotypic selection on tolerance: on average, individuals who lost weight more slowly with increasing parasite burden had higher lifetime breeding success. This variation did not have an additive genetic basis. These results reveal that selection on tolerance operates under natural conditions. They also support theoretical predictions for the erosion of additive genetic variance of traits under strong directional selection and fixation of genes conferring tolerance. Our findings provide the first evidence of selection on individual tolerance of infection in animals and suggest practical applications in animal and human disease management in the face of highly prevalent parasites.

  11. Natural Selection on Individual Variation in Tolerance of Gastrointestinal Nematode Infection

    PubMed Central

    Hayward, Adam D.; Nussey, Daniel H.; Wilson, Alastair J.; Berenos, Camillo; Pilkington, Jill G.; Watt, Kathryn A.; Pemberton, Josephine M.; Graham, Andrea L.

    2014-01-01

    Hosts may mitigate the impact of parasites by two broad strategies: resistance, which limits parasite burden, and tolerance, which limits the fitness or health cost of increasing parasite burden. The degree and causes of variation in both resistance and tolerance are expected to influence host–parasite evolutionary and epidemiological dynamics and inform disease management, yet very little empirical work has addressed tolerance in wild vertebrates. Here, we applied random regression models to longitudinal data from an unmanaged population of Soay sheep to estimate individual tolerance, defined as the rate of decline in body weight with increasing burden of highly prevalent gastrointestinal nematode parasites. On average, individuals lost weight as parasite burden increased, but whereas some lost weight slowly as burden increased (exhibiting high tolerance), other individuals lost weight significantly more rapidly (exhibiting low tolerance). We then investigated associations between tolerance and fitness using selection gradients that accounted for selection on correlated traits, including body weight. We found evidence for positive phenotypic selection on tolerance: on average, individuals who lost weight more slowly with increasing parasite burden had higher lifetime breeding success. This variation did not have an additive genetic basis. These results reveal that selection on tolerance operates under natural conditions. They also support theoretical predictions for the erosion of additive genetic variance of traits under strong directional selection and fixation of genes conferring tolerance. Our findings provide the first evidence of selection on individual tolerance of infection in animals and suggest practical applications in animal and human disease management in the face of highly prevalent parasites. PMID:25072883

  12. Insights into the naturally acquired immune response to Plasmodium vivax malaria.

    PubMed

    Longley, Rhea J; Sattabongkot, Jetsumon; Mueller, Ivo

    2016-02-01

    Plasmodium vivax is the most geographically widespread of the malaria parasites causing human disease, yet it is comparatively understudied compared with Plasmodium falciparum. In this article we review what is known about naturally acquired immunity to P. vivax, and importantly, how this differs to that acquired against P. falciparum. Immunity to clinical P. vivax infection is acquired more quickly than to P. falciparum, and evidence suggests humans in endemic areas also have a greater capacity to mount a successful immunological memory response to this pathogen. Both of these factors give promise to the idea of a successful P. vivax vaccine. We review what is known about both the cellular and humoral immune response, including the role of cytokines, antibodies, immunoregulation, immune memory and immune dysfunction. Furthermore, we discuss where the future lies in terms of advancing our understanding of naturally acquired immunity to P. vivax, through the use of well-designed longitudinal epidemiological studies and modern tools available to immunologists.

  13. Natural Variation in Dauer Pheromone Production and Sensing Supports Intraspecific Competition in Nematodes

    PubMed Central

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

    2015-01-01

    Summary Dauer formation, a major nematode survival strategy, represents a model for small-molecule regulation of metazoan development [1–10]. Free-living nematodes excrete dauer-inducing pheromones that have been assumed to target conspecifics of the same genotype [9, 11]. However, recent studies in Pristionchus pacificus revealed that the dauer pheromone of some strains affects conspecifics of other genotypes more strongly than individuals of the same genotype [12]. To elucidate the mechanistic basis for this intriguing cross-preference, we compared six P. pacificus wild isolates to determine the chemical composition of their dauer-inducing metabolomes and responses to individual pheromone components. We found that these isolates produce dauer pheromone blends of different composition and respond differently to individual pheromone components. Strikingly, there is no correlation between production of and dauer response to a specific compound in individual strains. Specifically, pheromone components that are abundantly produced by one genotype induce dauer formation in other genotypes, but not necessarily in the abundant producer. Furthermore, some genotypes respond to pheromone components they do not produce themselves. These results support a model of intraspecific competition in nematode dauer formation. Indeed, we observed intraspecific competition among sympatric strains in a novel experimental assay, suggesting a new role of small molecules in nematode ecology. PMID:24980503

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

    PubMed

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

    2014-07-07

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

  15. Signaling between nematodes and plants.

    PubMed

    Bird, David McK

    2004-08-01

    After hatching in the soil, root-knot nematodes must locate and penetrate a root, migrate into the vascular cylinder, and establish a permanent feeding site. Presumably, these events are accompanied by extensive signaling between the nematode parasite and the host. Hence, much emphasis has been placed on identifying proteins that are secreted by the nematode during the migratory phase. Further progress in understanding the signaling events has been made recently by studying the host response. Striking parallels can be drawn between the nematode-plant interaction and plant symbioses with other microorganisms, and evidence is emerging to suggest that nematodes acquired components of their parasitic armory from those microbes.

  16. Natural variation in Pristionchus pacificus dauer formation reveals cross-preference rather than self-preference of nematode dauer pheromones

    PubMed Central

    Mayer, Melanie G.; Sommer, Ralf J.

    2011-01-01

    Many free-living nematodes, including the laboratory model organisms Caenorhabditis elegans and Pristionchus pacificus, have a choice between direct and indirect development, representing an important case of phenotypic plasticity. Under harsh environmental conditions, these nematodes form dauer larvae, which arrest development, show high resistance to environmental stress and constitute a dispersal stage. Pristionchus pacificus occurs in a strong association with scarab beetles in the wild and remains in the dauer stage on the living beetle. Here, we explored the circumstances under which P. pacificus enters and exits the dauer stage by using a natural variation approach. The analysis of survival, recovery and fitness after dauer exit of eight P. pacificus strains revealed that dauer larvae can survive for up to 1 year under experimental conditions. In a second experiment, we isolated dauer pheromones from 16 P. pacificus strains, and tested for natural variation in pheromone production and sensitivity in cross-reactivity assays. Surprisingly, 13 of the 16 strains produce a pheromone that induces the highest dauer formation in individuals of other genotypes. These results argue against a simple adaptation model for natural variation in dauer formation and suggest that strains may have evolved to induce dauer formation precociously in other strains in order to reduce the fitness of these strains. We therefore discuss intraspecific competition among genotypes as a previously unconsidered aspect of dauer formation. PMID:21307052

  17. Parasite Manipulation of Its Host's Physiological Reaction to Acute Stress: Experimental Results from a Natural Beetle-Nematode System.

    PubMed

    Davis, Andrew K; Vasquez, David; LeFeuvre, Jake; Sims, Stuart; Craft, Meghan; Vizurraga, Anna

    All animals, whether vertebrate or invertebrate, must be capable of reacting to acute stressors, such as escaping from predators, and most do so with a suite of transient physiological changes that temporarily enhance survival. Some of these changes include mobilization of immune cells and increased cardiac output. A small but growing number of studies have begun to show that certain parasites appear capable of modifying such responses. We addressed this topic using a natural host and parasite system, that is, a nematode (Chondronema passali) that parasitizes horned passalus beetles, Odontotaenius disjunctus (family Passalidae), of the eastern United States. With a series of experiments, we sought to determine whether this parasite affects (1) the immune reaction to stress, (2) the output of stress-induced alarm calls, or (3) the increase in heart rate that occurs in response to acute stressors, with the stressors being mechanical or thermal. Results showed that hemocyte density increased after both stressors in nonparasitized beetles but did not increase in parasitized beetles. While mobilization of immune cells would enhance host immunity during stress, this would also be damaging to the nematode, so this scenario appears to benefit the parasite. We found no evidence that the nematode suppresses the overall reaction to stress (or prevents stress from occurring), since parasitized beetles did not differ from nonparasitized ones in alarm call rates or in heart beat frequency after exposure to mechanical stressors. Suppression of the host's normal immune reaction to stressful stimuli could translate to delayed or even reduced wound healing or pathogen resistance during these events. This project is a rare demonstration of parasite manipulation of host immune response to acute stress and should stimulate further investigations into the interactive nature of stress and parasites.

  18. Metabolomics and Natural-Products Strategies to Study Chemical Ecology in Nematodes

    PubMed Central

    Edison, Arthur S.; Clendinen, Chaevien S.; Ajredini, Ramadan; Beecher, Chris; Ponce, Francesca V.; Stupp, Gregory S.

    2015-01-01

    This review provides an overview of two complementary approaches to identify biologically active compounds for studies in chemical ecology. The first is activity-guided fractionation and the second is metabolomics, particularly focusing on a new liquid chromatography–mass spectrometry-based method called isotopic ratio outlier analysis. To illustrate examples using these approaches, we review recent experiments using Caenorhabditis elegans and related free-living nematodes. PMID:26141866

  19. Metabolomics and Natural-Products Strategies to Study Chemical Ecology in Nematodes.

    PubMed

    Edison, Arthur S; Clendinen, Chaevien S; Ajredini, Ramadan; Beecher, Chris; Ponce, Francesca V; Stupp, Gregory S

    2015-09-01

    This review provides an overview of two complementary approaches to identify biologically active compounds for studies in chemical ecology. The first is activity-guided fractionation and the second is metabolomics, particularly focusing on a new liquid chromatography-mass spectrometry-based method called isotopic ratio outlier analysis. To illustrate examples using these approaches, we review recent experiments using Caenorhabditis elegans and related free-living nematodes.

  20. A natural odor attraction between lactic acid bacteria and the nematode Caenorhabditis elegans

    PubMed Central

    Choi, Jae Im; Yoon, Kyoung-hye; Subbammal Kalichamy, Saraswathi; Yoon, Sung-Sik; Il Lee, Jin

    2016-01-01

    Animal predators can track prey using their keen sense of smell. The bacteriovorous nematode Caenorhabditis elegans employs sensitive olfactory sensory neurons that express vertebrate-like odor receptors to locate bacteria. C. elegans displays odor-related behaviors such as attraction, aversion and adaptation, but the ecological significance of these behaviors is not known. Using a combination of food microbiology and genetics, we elucidate a possible predator–prey relationship between C. elegans and lactic acid bacteria (LAB) in rotting citrus fruit. LAB produces the volatile odor diacetyl as an oxidized by-product of fermentation in the presence of citrate. We show that C. elegans is attracted to LAB when grown on citrate media or Citrus medica L, commonly known as yuzu, a citrus fruit native to East Asia, and this attraction is mediated by the diacetyl odor receptor, ODR-10. We isolated a wild LAB strain and a wild C. elegans-related nematode from rotten yuzu, and demonstrate that the wild nematode was attracted to the diacetyl produced by LAB. These results not only identify an ecological function for a C. elegans olfactory behavior, but contribute to the growing understanding of ecological relationships between the microbial and metazoan worlds. PMID:26241504

  1. A natural odor attraction between lactic acid bacteria and the nematode Caenorhabditis elegans.

    PubMed

    Choi, Jae Im; Yoon, Kyoung-Hye; Subbammal Kalichamy, Saraswathi; Yoon, Sung-Sik; Il Lee, Jin

    2016-03-01

    Animal predators can track prey using their keen sense of smell. The bacteriovorous nematode Caenorhabditis elegans employs sensitive olfactory sensory neurons that express vertebrate-like odor receptors to locate bacteria. C. elegans displays odor-related behaviors such as attraction, aversion and adaptation, but the ecological significance of these behaviors is not known. Using a combination of food microbiology and genetics, we elucidate a possible predator-prey relationship between C. elegans and lactic acid bacteria (LAB) in rotting citrus fruit. LAB produces the volatile odor diacetyl as an oxidized by-product of fermentation in the presence of citrate. We show that C. elegans is attracted to LAB when grown on citrate media or Citrus medica L, commonly known as yuzu, a citrus fruit native to East Asia, and this attraction is mediated by the diacetyl odor receptor, ODR-10. We isolated a wild LAB strain and a wild C. elegans-related nematode from rotten yuzu, and demonstrate that the wild nematode was attracted to the diacetyl produced by LAB. These results not only identify an ecological function for a C. elegans olfactory behavior, but contribute to the growing understanding of ecological relationships between the microbial and metazoan worlds.

  2. The reindeer abomasal nematode (Ostertagia gruehneri) is naturally transmitted to sheep when sharing pastures.

    PubMed

    Manninen, Saana-Maaria; Thamsborg, Stig M; Laaksonen, Sauli; Oksanen, Antti

    2014-11-01

    The increasing number of sheep (Ovis aries) in northern Finland, often alternately corralled with winter-fed reindeer (Rangifer tarandus tarandus), creates potential for cross-infection of gastrointestinal nematodes. The aim of this study was to elucidate this possibility with 43 animals. Eleven reindeer and 8 sheep had shared a corral by turns, reindeer during winters, and sheep in summers. Another 12 reindeer had no known contact with sheep. Twelve sheep had no close contact to other ruminants. Both reindeer groups were free-ranging during summers. During slaughter in September to November, 2003, abomasa and parts of intestines were collected. Gastrointestinal nematodes were counted and identified. The species found were the following: in reindeer, Ostertagia gruehneri/Ostertagia arctica, Mazamastrongylus dagestanica, Nematodirus tarandi, Nematodirella longissimespiculata and Bunostomum trigonocephalum; in sheep, Teladorsagia circumcincta/Teladorsagia trifurcata, O. gruehneri/O. arctica, Nematodirus filicollis and N. spathiger. In the sheep sharing corral with reindeer, the only abomasal nematode species found was O. gruehneri, a reindeer parasite. The generation interval of O. gruehneri in Finnish reindeer appears to be shorter than in Canadian Arctic caribou, where complete larval inhibition leading to only one generation yearly has been reported.

  3. Naturally Acquired Mentoring Relationships and Young Adult Outcomes among Adolescents with Learning Disabilities

    ERIC Educational Resources Information Center

    Ahrens, Kym; DuBois, David Lane; Lozano, Paula; Richardson, Laura P.

    2010-01-01

    We evaluated whether having a naturally acquired mentor during adolescence was associated with improved adult outcomes among youth with learning disabilities (YLD). Mentored youth were more likely to have graduated from high school, reported a higher level of self-esteem, and reported a higher overall number of positive outcomes than nonmentored…

  4. Speech perception and reading: two parallel modes of understanding language and implications for acquiring literacy naturally.

    PubMed

    Massaro, Dominic W

    2012-01-01

    I review 2 seminal research reports published in this journal during its second decade more than a century ago. Given psychology's subdisciplines, they would not normally be reviewed together because one involves reading and the other speech perception. The small amount of interaction between these domains might have limited research and theoretical progress. In fact, the 2 early research reports revealed common processes involved in these 2 forms of language processing. Their illustration of the role of Wundt's apperceptive process in reading and speech perception anticipated descriptions of contemporary theories of pattern recognition, such as the fuzzy logical model of perception. Based on the commonalities between reading and listening, one can question why they have been viewed so differently. It is commonly believed that learning to read requires formal instruction and schooling, whereas spoken language is acquired from birth onward through natural interactions with people who talk. Most researchers and educators believe that spoken language is acquired naturally from birth onward and even prenatally. Learning to read, on the other hand, is not possible until the child has acquired spoken language, reaches school age, and receives formal instruction. If an appropriate form of written text is made available early in a child's life, however, the current hypothesis is that reading will also be learned inductively and emerge naturally, with no significant negative consequences. If this proposal is true, it should soon be possible to create an interactive system, Technology Assisted Reading Acquisition, to allow children to acquire literacy naturally.

  5. Long-term effects of drenches with condensed tannins from Acacia mearnsii on goats naturally infected with gastrointestinal nematodes.

    PubMed

    Costa-Júnior, Livio M; Costa, Jailson S; Lôbo, Ítala C P D; Soares, Alexandra M S; Abdala, Adibe L; Chaves, Daniel P; Batista, Zulmira S; Louvandini, Helder

    2014-10-15

    In this study, the long-term effects of exposure to a drench containing condensed tannins (CTs) from Acacia mearnsii on gastrointestinal nematodes in goats were investigated. Male cross-bred Anglo-Nubian goat kids between 3 and 5 months of age were dewormed at the beginning of the experiment. The goat kids were divided into one group that received weekly 24 g oral doses of A. mearnsii bark extract dissolved in water containing 16.7% CTs (GCT group, n = 8) and a second group that did not receive CTs (GC group, n = 8). All of the animals were kept in an Andropogon gayanus pasture and grazed with a herd of 100 naturally infected adult goats. Each animal was supplemented daily with 200 g of a concentrated mixture containing 18% crude protein. Fecal egg counts (FECs) were performed weekly for 192 days, and weight measurements and blood collections were done at two-week intervals in this period. The packed cell volume of the blood was calculated, and the plasma was used to determine the total protein, albumin, and glucose concentrations. After 192 days, the animals were slaughtered and the carcasses evaluated, with nematodes harvested for identification and counting. The FECs of the animals treated with CTs from A. mearnsii (GCT group) remained lower than the FECs of the control group animals for the majority of the first half of the experimental period. An observed increase in the FECs for both groups coincided with increased rainfall in the region where the experiment was conducted. The worm burden, scrotal circumference, carcass weight, leg circumference, carcass size and blood analysis were not significantly different between the groups. The packed cell volume (PCV) was constant in all of the animals throughout the experiment. In conclusion, repeated and prolonged treatment of goats with CTs from A. mearnsii helped to maintain low FECs in a period of low challenge but did not reduce nematode infections in the goats.

  6. The host immune response to gastrointestinal nematode infection in sheep.

    PubMed

    McRae, K M; Stear, M J; Good, B; Keane, O M

    2015-12-01

    Gastrointestinal nematode infection represents a major threat to the health, welfare and productivity of sheep populations worldwide. Infected lambs have a reduced ability to absorb nutrients from the gastrointestinal tract, resulting in morbidity and occasional mortality. The current chemo-dominant approach to nematode control is considered unsustainable due to the increasing incidence of anthelmintic resistance. In addition, there is growing consumer demand for food products from animals not subjected to chemical treatment. Future mechanisms of nematode control must rely on alternative, sustainable strategies such as vaccination or selective breeding of resistant animals. Such strategies take advantage of the host's natural immune response to nematodes. The ability to resist gastrointestinal nematode infection is considered to be dependent on the development of a protective acquired immune response, although the precise immune mechanisms involved in initiating this process remain to be fully elucidated. In this study, current knowledge on the innate and acquired host immune response to gastrointestinal nematode infection in sheep and the development of immunity is reviewed. © 2015 John Wiley & Sons Ltd.

  7. Natural Occurrence of Entomopathogenic Nematodes (Rhabditida: Steinernema, Heterorhabditis) in the Azores

    PubMed Central

    Rosa, J. S.; Bonifassi, E.; Amaral, J.; Lacey, L. A.; Simões, N.; Laumond, C.

    2000-01-01

    A soil survey for entomopathogenic nematodes was conducted throughout the nine islands of the Azorean archipelago. Forty-six out of 1,180 samples (3.9%) were positive, with Heterorhabditis spp. isolated from 30 sites on six islands and Steinernema spp. isolated from 16 sites on three islands. São Miguel and Terceira Islands were positive for both genera, and Pico Island was positive only for Steinernema. Entomopathogenic nematodes were found from sea level up to 750 m. Seventy percent of the samples positive for Heterorhabditis were collected below 150 m, whereas 62.5% of the samples positive for Steinernema were collected above 300 m. Heterorhabditis was not isolated above 450 m. Steinernema was collected mostly in loamy-sand and sandy-loam soils with a pH below 6, whereas Heterorhabditis was mostly collected in sandy and loamy-sand soils with pH higher than 6. Steinernema and Heterorhabditis were found in cropland, orchards, and pastures, while Heterorhabditis was found also in woodland and native vegetation. PMID:19270969

  8. Natural Acquired Immunity Against Subsequent Genital Human Papillomavirus Infection: A Systematic Review and Meta-analysis.

    PubMed

    Beachler, Daniel C; Jenkins, Gwendolyne; Safaeian, Mahboobeh; Kreimer, Aimée R; Wentzensen, Nicolas

    2016-05-01

    Studies have been mixed on whether naturally acquired human papillomavirus (HPV) antibodies may protect against subsequent HPV infection. We performed a systematic review and meta-analysis to assess whether naturally acquired HPV antibodies protect against subsequent genital HPV infection (ie, natural immunity). We searched the MEDLINE and EMBASE databases for studies examining natural HPV immunity against subsequent genital type-specific HPV infection in female and male subjects. We used random-effects models to derive pooled relative risk (RR) estimates for each HPV type. We identified 14 eligible studies that included >24,000 individuals from 18 countries that examined HPV natural immunity. We observed significant protection against subsequent infection in female subjects with HPV-16 (pooled RR, 0.65; 95% confidence interval, .50-.80) and HPV-18 (0.70; .43-.98) but not in male subjects (HPV-16: 1.22; .67-1.77 [P= .05 (test for heterogeneity)]; HPV-18: 1.50; .46-2.55; [P= .15]). We also observed type-specific protection against subsequent infection for a combined measure of HPV-6/11/31/33/35/45/52/58 in female subjects (pooled RR, 0.75; 95% confidence interval, .57-.92). Natural immunity was also evident in female subjects when analyses were restricted to studies that used neutralizing assays, used HPV persistence as an outcome, or reported adjusted analyses (each P< .05). HPV antibodies acquired through natural infection provide modest protection against subsequent cervical HPV infection in female subjects. Published by Oxford University Press for the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  9. Anthelmintic activity of Artemisia annua L. extracts in vitro and the effect of an aqueous extract and artemisinin in sheep naturally infected with gastrointestinal nematodes

    USDA-ARS?s Scientific Manuscript database

    There is no effective natural alternative control for gastrointestinal nematodes (GIN) of small ruminants, with Haemonchus contortus being the most economically important GIN. Despite frequent reports of multidrug-resistant GIN, there is no new commercial anthelmintic to substitute failing ones. Alt...

  10. The effects of strawberry cropping practices on the strawberry tortricid (Lepidoptera: Tortricidae), its natural enemies, and the presence of nematodes.

    PubMed

    Sigsgaard, Lene; Naulin, Cyril; Haukeland, Solveig; Kristensen, Kristian; Enkegaard, Annie; Jensen, Nauja Lisa; Eilenberg, Jørgen

    2014-01-01

    Cropping practice can affect pests and natural enemies. A three-year study of the strawberry tortricid, Acleris comariana (Lienig and Zeller) (Lepidoptera: Tortricidae), its parasitoid Copidosoma aretas Walker (Hymenoptera: Encyrtidae), and its entomopathogenic fungi was conducted in seven pairs of organic and conventional farms to test the hypothesis that farming practice (organic versus conventional) will affect the level of pest infestation and will affect the natural enemies. In addition, the number of years with strawberries on the farm, field age, and other factors that may affect pests and their natural enemies were considered. Farms were characterized by their cropping practices, cropping history, and other parameters. Field-collected larvae were laboratory reared to assess mortality from parasitoids and entomopathogenic fungi. In 2010, a survey of nematodes was made to assess the response of an unrelated taxonomic group to cropping practice. 2,743 larvae were collected. Of those, 2,584 were identified as A. comariana. 579 A. comariana were parasitized by C. aretas and 64 A. comariana were parasitized by other parasitoid species. Finally, 28% of the larvae and pupae of A. comariana died from unknown causes. Only two of the field-collected A. comariana larvae were infected by entomopathogenic fungi; one was infected by Isaria sp. and the other by Beauvaria sp. The density of A. comariana was on average four times lower in organic farms, which was significantly lower than in conventional farms. A. comariana was more dominant on conventional farms than on organic farms. The effect of crop age (One, two, or three years) on A. comariana infestation was significant, with higher infestations in older fields. Crop age had no effect on A. comariana infestation in a comparison of first- and second-year fields in 2010. Cropping practice did not lead to significant differences in the level of total parasitism or in C. aretas parasitism; however, C. aretas contributed

  11. The Effects of Strawberry Cropping Practices on the Strawberry Tortricid (Lepidoptera: Tortricidae), Its Natural Enemies, and the Presence of Nematodes

    PubMed Central

    Sigsgaard, Lene; Naulin, Cyril; Haukeland, Solveig; Kristensen, Kristian; Enkegaard, Annie; Jensen, Nauja Lisa; Eilenberg, Jørgen

    2014-01-01

    Cropping practice can affect pests and natural enemies. A three-year study of the strawberry tortricid, Acleris comariana (Lienig and Zeller) (Lepidoptera: Tortricidae), its parasitoid Copidosoma aretas Walker (Hymenoptera: Encyrtidae), and its entomopathogenic fungi was conducted in seven pairs of organic and conventional farms to test the hypothesis that farming practice (organic versus conventional) will affect the level of pest infestation and will affect the natural enemies. In addition, the number of years with strawberries on the farm, field age, and other factors that may affect pests and their natural enemies were considered. Farms were characterized by their cropping practices, cropping history, and other parameters. Field-collected larvae were laboratory reared to assess mortality from parasitoids and entomopathogenic fungi. In 2010, a survey of nematodes was made to assess the response of an unrelated taxonomic group to cropping practice. 2,743 larvae were collected. Of those, 2,584 were identified as A. comariana. 579 A. comariana were parasitized by C. aretas and 64 A. comariana were parasitized by other parasitoid species. Finally, 28% of the larvae and pupae of A. comariana died from unknown causes. Only two of the field-collected A. comariana larvae were infected by entomopathogenic fungi; one was infected by Isaria sp. and the other by Beauvaria sp. The density of A. comariana was on average four times lower in organic farms, which was significantly lower than in conventional farms. A. comariana was more dominant on conventional farms than on organic farms. The effect of crop age (One, two, or three years) on A. comariana infestation was significant, with higher infestations in older fields. Crop age had no effect on A. comariana infestation in a comparison of first- and second-year fields in 2010. Cropping practice did not lead to significant differences in the level of total parasitism or in C. aretas parasitism; however, C. aretas contributed

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

    PubMed Central

    Haran, Julien; Roques, Alain; Bernard, Alexis; Robinet, Christelle; Roux, Géraldine

    2015-01-01

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

  13. Anthelmintic efficacy of an oral formulation of Aurixazol against gastrointestinal nematodes of naturally and experimentally infected sheep.

    PubMed

    Sakamoto, Claudio Alessandro M; Lopes, Welber Daniel Zanetti; Buzzulini, Carolina; Cruz, Breno Cayeiro; Felippelli, Gustavo; de Lima, Roberto Cesar Araújo; dos Santos, Thais Rabelo; Santana, Luis Fernando; de Mendonça, Rafael Paranhos; Soares, Vando Edésio; Henrique, Carlos Henrique; da Costa, Alvimar José

    2013-12-06

    As a result of the need to develop new active principles for the control of endoparasites in ruminants, the present in vivo study evaluated a formulation containing 24% Aurixazol (48 mg/kg), a parasiticide molecule based on disophenolate of levamisole. Two experiments were conducted: one evaluating the anthelmintic efficacy of 24% Aurixazol (48 mg/kg) against gastrointestinal nematodes in naturally infected sheep, compared to an association of ivermectin (0.2mg/kg)+albendazole (5.0mg/kg)+levamisole (7.5mg/kg) (IAL), and a second one which evaluated the persistent efficacy of the same formulation against immature stages (L4) and adults of Haemonchus contortus in experimentally infected animals. In experiment I, against H. contortus, the formulation of Aurixazol and the IAL association reached efficacies (arithmetic means) of 99.32% and 96.11%, respectively. For Trichostrongylus colubriformis, the efficacy values were 88.92% and 98.08% for Aurixazol and the IAL association, respectively. Both formulations were totally effective against Oesophagostomum columbianum (100%). The results of the statistical analysis demonstrated that the mean parasitic burden of treated animals was significantly different (P ≤ 0.05) compared to the average number of helminths diagnosed in animals from the control group for H. contortus, T. colubriformis and O. columbianum. Comparing only the treated groups, it was possible to verify that the average number of H. contortus recovered from animals treated with Aurixazol was different (P ≤ 0.05) when compared to the mean amount recovered from sheep treated with the IAL association. When evaluating the prevention of H. contortus infection in experiment II, Aurixazol did not present preventive efficacy. Up until 21 days after treatment the groups treated with Aurixazol contained less adults and L4 of H. contortus (P ≤ 0.05) when compared to the non-medicated control group. However, future studies will be necessary to assess the

  14. Naturally Acquired Human Immunity to Pneumococcus Is Dependent on Antibody to Protein Antigens

    PubMed Central

    Reglinski, Mark; Jose, Ricardo J.; Marshall, Helina; de Vogel, Corné; Gordon, Stephen; Petersen, Fernanda C.; Baxendale, Helen

    2017-01-01

    Naturally acquired immunity against invasive pneumococcal disease (IPD) is thought to be dependent on anti-capsular antibody. However nasopharyngeal colonisation by Streptococcus pneumoniae also induces antibody to protein antigens that could be protective. We have used human intravenous immunoglobulin preparation (IVIG), representing natural IgG responses to S. pneumoniae, to identify the classes of antigens that are functionally relevant for immunity to IPD. IgG in IVIG recognised capsular antigen and multiple S. pneumoniae protein antigens, with highly conserved patterns between different geographical sources of pooled human IgG. Incubation of S. pneumoniae in IVIG resulted in IgG binding to the bacteria, formation of bacterial aggregates, and enhanced phagocytosis even for unencapsulated S. pneumoniae strains, demonstrating the capsule was unlikely to be the dominant protective antigen. IgG binding to S. pneumoniae incubated in IVIG was reduced after partial chemical or genetic removal of bacterial surface proteins, and increased against a Streptococcus mitis strain expressing the S. pneumoniae protein PspC. In contrast, depletion of type-specific capsular antibody from IVIG did not affect IgG binding, opsonophagocytosis, or protection by passive vaccination against IPD in murine models. These results demonstrate that naturally acquired protection against IPD largely depends on antibody to protein antigens rather than the capsule. PMID:28135322

  15. Improving resilience against natural gastrointestinal nematode infections in browsing kids during the dry season in tropical Mexico.

    PubMed

    Torres-Acosta, J F J; Jacobs, D E; Aguilar-Caballero, A J; Sandoval-Castro, C; Cob-Galera, L; May-Martínez, M

    2006-01-30

    The objective was to determine the effect of supplementary feeding on the resilience and resistance of Criollo kids against natural gastrointestinal nematode (GIN) infections, when browsing native vegetation during the dry season in tropical Mexico. Thirty-three two-month-old Criollo kids, raised nematode free, were included at weaning in a 20-week trial. The kids were placed into four groups. Two groups of eight kids were offered 100g/day soybean and sorghum meal (26%:74% respectively fresh basis) (treated/supplemented (T-S) and infected/supplemented (I-S)). Two groups remained with no supplement for the duration of the trial (infected/non-supplemented (I-NS) (n=9) and treated/non-supplemented (T-NS) (n=8)). Kids in groups T-S and T-NS were drenched with 0.2mg of moxidectin/kg body weight orally (Cydectin, Fort Dodge) every 28 days. Groups I-S and I-NS were naturally infected with GIN. The animals browsed native vegetation for an average of 7h/day together with a herd of 120 naturally infected adult goats. Cumulative live weight gain (CLWG), packed cell volume (PCV), haemoglobin (Hb), total plasma protein and plasma albumin were recorded every 14 days as measurements of resilience. Resistance parameters (faecal egg counts (FEC) and peripheral eosinophil counts (PEC)) were also measured. Bulk faecal cultures were made for each group every 28 days. Every month a new pair of initially worm-free tracer kids assessed the infectivity of the vegetation browsed by the animals. Tracer kids and faecal cultures showed that kids faced low mixed infections (Haemonchus contortus, Trichostrongylus colubriformis and Oesophagostomum columbianum). Under conditions of scarce vegetation, such as those in the present study, supplemented groups (I-S and T-S) had higher growth rates compared to the non-supplemented groups independently of the control of GIN infection with anthelmintic (AH) treatment (P<0.001). Supplementary feeding did not affect FEC or PEC. In the absence of

  16. Naturally acquired anthrax antibodies in a cheetah (Acinonyx jubatus) in Botswana.

    PubMed

    Good, Kyle M; Houser, Annmarie; Arntzen, Lorraine; Turnbull, Peter C B

    2008-07-01

    An outbreak of anthrax in the Jwana Game Reserve in Jwaneng, Botswana, was first observed when three cheetahs (Acinonyx jubatus) died of the disease in November 2004. In the aftermath of this event, banked serum samples collected from 23 wild-caught cheetahs were examined, by the inhibition enzyme-linked immunoassay (ELISA), for antibodies to the protective antigen (PA) of Bacillus anthracis. Of the 23 cheetahs, 16 regularly accessed the reserve. Antibodies to PA were detected in one cheetah collected in May 2004, indicating the disease was occurring well before it was first noticed. This appears to be the first demonstration of naturally acquired anthrax antibodies in cheetahs. The finding of one antibody-positive animal amongst at least 16 potentially exposed individuals is consistent with existing reports that it is uncommon for cheetahs to develop natural immunity to anthrax.

  17. Naturally Acquired Immunity Against Rotavirus Infection and Gastroenteritis in Children: Paired Reanalyses of Birth Cohort Studies.

    PubMed

    Lewnard, Joseph A; Lopman, Benjamin A; Parashar, Umesh D; Bar-Zeev, Naor; Samuel, Prasanna; Guerrero, M Lourdes; Ruiz-Palacios, Guillermo M; Kang, Gagandeep; Pitzer, Virginia E

    2017-08-01

    Observational studies in socioeconomically distinct populations have yielded conflicting conclusions about the strength of naturally acquired immunity against rotavirus gastroenteritis (RVGE), mirroring vaccine underperformance in low-income countries. We revisited birth cohort studies to understand naturally acquired protection against rotavirus infection and RVGE. We reanalyzed data from 200 Mexican and 373 Indian children followed from birth to 2 and 3 years of age, respectively. We reassessed protection against RVGE, decomposing the incidence rate into the rate of rotavirus infection and the risk of RVGE given infection, and tested for serum antibody correlates of protection using regression models. Risk for primary, secondary, and subsequent infections to cause RVGE decreased per log-month of age by 28% (95% confidence interval [CI], 12%-41%), 69% (95% CI, 30%-86%), and 64% (95% CI, -186% to 95%), respectively, in Mexico City, and by 10% (95% CI, -1% to 19%), 51% (95% CI, 41%-59%) and 67% (95% CI, 57%-75%), respectively, in Vellore. Elevated serum immunoglobulin A and immunoglobulin G titers were associated with partial protection against rotavirus infection. Associations between older age and reduced risk for RVGE or moderate-to-severe RVGE given infection persisted after controlling for antibody levels. Dissimilar estimates of protection against RVGE may be due in part to age-related, antibody-independent risk for rotavirus infections to cause RVGE.

  18. A Look into Students' Retention of Acquired Nature of Science Understandings

    NASA Astrophysics Data System (ADS)

    Khishfe, Rola

    2015-07-01

    Having the learning and retention of science content and skills as a goal of scientific literacy, it is significant to study the issue of retention as it relates to teaching and learning about nature of science (NOS). Then, the purpose of this study was to investigate the development of NOS understandings of students, and the retention of these understandings four months after being acquired through explicit reflective instruction in relation to two contexts. Participants were 24 tenth-grade students at a private high school in a city in the Middle East. Explicit NOS instruction was addressed within a six-week unit about genetic engineering. Three NOS aspects were integrated and dispersed across the unit. A questionnaire, together with semi-structured interviews, was administered as pre-, post-, and delayed post-test to assess the retention of participants' NOS understandings. The questionnaire had two open-ended scenarios addressing controversial socioscientific issues about genetically modified food and water fluoridation. Results showed that most students improved their naïve understandings of NOS in relation to the two contexts following the six-week unit with the explicit NOS instruction. However, these newly acquired NOS understandings were not retained by all students four months after instruction. Many of the students reverted back to their earlier naïve understandings. Conclusions about the factors facilitating the process of retention as the orientation to meaningful learning and the prolonged exposure to the domain were discussed in relation to practical implications in the classroom.

  19. A natural setting behavior management program for persons with acquired brain injury: a randomized controlled trial.

    PubMed

    Carnevale, George J; Anselmi, Vera; Johnston, Mark V; Busichio, Kim; Walsh, Vanessa

    2006-10-01

    To investigate the efficacy of a behavior management program delivered in the natural community setting for persons with brain injury and their caregivers. Three-group randomized controlled trial. Homes and other community settings. Thirty-seven persons with traumatic and other acquired brain injury and their caregivers. Natural Setting Behavior Management (NSBM) involving education and individualized behavior modification program versus education only versus control group. Changes in frequency of targeted problematic behaviors. Subscale in Questionnaire on Resources and Stress, Maslach Burnout Inventory, and the Neurobehavioral Functioning Inventory. While no significant effects were detected at termination of education only (P<.075) or of NSBM (P<.56), significant treatment effects were found at the main outcome point 3 months after termination of services (P<.002). Rates of disruptive or aggressive behaviors declined significantly in the NSBM group. Differences in caregiver-rated stress, burden, and aggression were not statistically significant. A program of caregiver education and individualized behavior management in natural settings can decrease the frequency of disruptive behavioral challenges. Larger studies are needed to clarify the duration and intensity of education and individualized treatment required to diminish behavioral challenges and to understand relationships with general stress and burden experienced by caregivers.

  20. Elimination of laboratory-acquired cadmium by the oyster Crassostrea virginica in the natural environment

    SciTech Connect

    Mowdy, D.E.

    1981-03-01

    Many productive shellfish-growing areas along the coast of the United States are closed because of pollution from domestic and industrial wastes. Many estuarine areas that are closed to shellfish harvesting because of bacterial pollution contain productive shellfish beds. These shellfish can be used as commercial food products after they have been relayed to approved growing waters and allowed to eliminate the polluting organisms. Relaying is not presently applied to shellfish contaminated with toxic metals for several reasons: There are no standards to control metal pollution (other than mercury) in seafood; few public health problems in this country involve toxic levels of trace metals in oysters; and not enough information is available to indicate the feasibility of such a project. This study demonstrates the feasibility of relaying cadmium-contaminated oysters to observe cadmium elimination. Because oysters containing naturally acquired cadmium were not readily available, oysters containing laboratory-incurred cadmium were studied.

  1. The role of naturally-acquired bacterial infection in influenza-related death in neonatal ferrets.

    PubMed Central

    Husseini, R. H.; Collie, M. H.; Rushton, D. I.; Sweet, C.; Smith, H.

    1983-01-01

    Concomitant, naturally-acquired bacterial infection was the cause of some deaths occurring in neonatal ferrets infected with the attenuated influenza virus A/Puerto Rico/8/34, these being prevented by antibiotic therapy. Bacterial infection played an insignificant role in the greater number of deaths following inoculation with the virulent clone 7a (of the recombinant influenza virus A/Puerto Rico/8/34-A/England/939/69/(H3N2]. As seen previously with clone 7a some ferret neonates infected with A/PR/8/34 died either from obstruction in the upper respiratory tract or from viral pneumonia, but with the latter virus, both types of lesion were probably attributable to the bacterial superinfection. PMID:6639875

  2. Natural history of vertically acquired HCV infection and associated autoimmune phenomena.

    PubMed

    Garazzino, Silvia; Calitri, Carmelina; Versace, Antonella; Alfarano, Alda; Scolfaro, Carlo; Bertaina, Chiara; Vatrano, Simona; Mignone, Federica; Licciardi, Francesco; Gabiano, Clara; Tovo, Pier-Angelo

    2014-08-01

    The natural history of vertically acquired HCV infection is ill defined. The aim of this study was to outline the natural course of vertical HCV infection in a cohort of untreated children, including rate of spontaneous viral clearance, frequency and features of HCV-related autoimmune disorders. Children with vertical HCV infection were prospectively followed from the first month of life with regular clinical and laboratory assessments. Statistical analysis was performed using Prism 5.0. Forty-five children (median age 12 years, interquartile range 6.9-15.5) were studied. Genotype 1 was predominant (53.3 %). Spontaneous viral clearance was achieved by 12 patients (26.7 %) and associated with genotype 3. Alanine-amino-transferase levels were increased in most children in the first 2 years of life with higher values in those who later cleared the infection. All children were asymptomatic for liver disease. Transient elastography (32 patients) showed mild or moderate fibrosis in nine and two cases, respectively. Non-organ-specific autoantibodies were detected in 24 children (53.3 %) independently of viremia; of these, one developed type-1 diabetes. Cryoglobulinemia was associated with genotype 1 infection and found in 15 subjects (33.3 %): two had low C4 levels and persistent proteinuria. Vertically acquired HCV infection may result in spontaneous clearance in up to 27 % of children. Resolution of infection is higher with genotype 3, usually occurs in preschool age and persists over time. Chronic infection is generally asymptomatic, although hepatomegaly and mild fibrosis may develop. Autoantibodies and cryoglobulins are frequent, whereas the associated clinical manifestations are rare.

  3. Efficacy of pyrantel pamoate and ivermectin paste formulations against naturally acquired Oxyuris equi infections in horses.

    PubMed

    Reinemeyer, Craig R; Prado, Julio C; Nichols, Eric C; Marchiondo, Alan A

    2010-07-15

    In recent years, numerous veterinary practitioners have reported anecdotal episodes in which anthelmintic treatment did not appear to deliver the expected efficacy against equine pinworms (Oxyuris equi). Anthelmintic resistance has not been demonstrated formally in equine pinworms, so a clinical study was designed to evaluate the efficacy of paste formulations of pyrantel pamoate or ivermectin against naturally acquired infections with O. equi. Twenty-one horses (>4 months to 15 years of age) with patent, naturally acquired pinworm infections were blocked by source of origin and allocated randomly to one of three treatment groups: horses (n=7) assigned to Group 1 were treated orally with pyrantel pamoate paste at a dosage of 13.2 mg/kg (2x label dosage), Group 2 horses (n=7) were untreated controls, and horses (n=7) assigned to Group 3 were treated orally with ivermectin paste at a dosage of 200 microg/kg. Fourteen days after treatment, horses were euthanatized, necropsied, and large intestinal contents were processed for recovery of adult pinworms. In addition, duplicate 1% aliquots of intestinal contents from the cecum, ventral colon, dorsal colon, and small colon were collected, preserved, and examined for recovery and enumeration of fourth-stage larval O. equi. Anthelmintic efficacy against pinworms was evaluated by comparing the post-treatment worm counts of Groups 1 and 3 to those of control animals. Mean numbers of O. equi adults recovered postmortem were significantly decreased by both pyrantel pamoate (P=0.0366) and ivermectin (P=0.0137) treatment, with respective efficacies of 91.2% and 96.0%. In addition, both products demonstrated >99% efficacy against fourth-stage O. equi larvae. The current study demonstrated acceptable adulticidal and larvicidal efficacy of both pyrantel pamoate and ivermectin paste formulations against O. equi and did not support the existence of macrocyclic lactone or pyrimidine resistance in the pinworm populations evaluated.

  4. Effect of an Orange Oil Emulsion on Gastrointestinal Nematodes in Naturally Infected Sheep

    USDA-ARS?s Scientific Manuscript database

    Increasing levels of anthelmintic resistance in ovine gastrointestinal strongylids, especially Haemonchus contortus, have led many investigators worldwide to examine potential anthelmintic effects of naturally occurring plant products. In previous work, we have shown that 1200 mg/kg of an orange oi...

  5. Using entomopathogenic nematodes for crop insect control

    USDA-ARS?s Scientific Manuscript database

    The objective of this paper is to provide an overview on using entomopathogenic nematodes for insect pest control. Entomopathogenic nematodes (genera Steinernema and Heterorhabditis), are be used as natural biopesticides. Unlike plant parasitic nematodes, which can be serious crop pests, entomopat...

  6. In vivo production of entomopathogenic nematodes

    USDA-ARS?s Scientific Manuscript database

    In nature, entomopathogenic nematodes in the genera Heterorhabditis and Steinernema are obligate parasites of insects. The nematodes are used widely as biocontrol agents for insect pests. More than a dozen entomopathogenic nematode species have been commercialized for use as biopesticides. One of ...

  7. Efficacy of a topical combination of fipronil, (S)-methoprene, eprinomectin and praziquantel (Broadline(®)) against naturally acquired infections with cestodes of the genus Joyeuxiella in cats.

    PubMed

    Schuster, Rolf K; Mustafa, Murad Basheer; Baskar, Jagadeesan Vijay; Rosentel, Joseph; Chester, S Theodore; Knaus, Martin

    2016-07-01

    Cats are host to dipylidiid cestodes of the genera Diplopylidium, Dipylidium and Joyeuxiella. Broadline(®), a topical broad-spectrum combination parasiticide containing fipronil (8.3 % w/v), (S)-methoprene (10 % w/v), eprinomectin (0.4 % w/v) and the cestocide praziquantel (8.3 % w/v), has previously been shown to be efficacious against Dipylidium caninum and Diplopylidium spp. in cats. To evaluate its efficacy against Joyeuxiella species, a blinded clinical efficacy study was conducted according to GCP. All cats had evidence for naturally acquired dipylidiid cestode infection as confirmed by pre-treatment examination. Cats were allocated randomly to two groups of 13 cats each based on bodyweight: Control (untreated) and Broadline(®) at 0.12 mL/kg bodyweight administered once topically. Based on the comparison of helminth counts in the treated and untreated cats seven days post treatment, Broadline(®) demonstrated >99 % efficacy (p < 0.01) against mature J. fuhrmanni and J. pasqualei, with 11 and 13 of the untreated cats harbouring 1 to 102 or 2 to 95 cestodes, respectively. In addition, parasite counts indicated 95.9 % efficacy (p = 0.006) against the rictularoid nematode Pterygodermatites cahirensis.

  8. Comparing the phenotypic susceptibility of Pelibuey and Katahdin female lambs against natural gastrointestinal nematode infections under hot humid tropical conditions.

    PubMed

    Palomo-Couoh, J G; Aguilar-Caballero, A J; Torres-Acosta, J F J; González-Garduño, R

    2017-06-01

    This study compared the phenotypic susceptibility of Pelibuey and Katahdin female lambs against gastrointestinal nematodes (GINs) under grazing conditions in the hot humid tropics of Mexico. The study was performed during the rainy season (August to October, 2014). It included 27 Pelibuey and 12 Katahdin female lambs from 6 months of age and live weight of 21.0 ± 3.7 and 23.3 ± 3.6 kg, respectively. Lambs were reared free of GIN infection before the study. The study lasted 91 days. Animals were weighed and sampled (blood and feces) on days 0 and 28 and every 7 days onwards. Fecal samples were obtained to determine fecal eggs of GIN per gram (EPG), and blood samples were used to determine the packed cell volume (PCV), the peripheral eosinophil counts (PECs), and optical densities (ODs) for IgA. The EPG counts were significantly lower for Pelibuey lambs compared to Katahdin throughout the study (P < 0.001). Similarly, Pelibuey lambs had higher mean PCV (P < 0.01) and PEC (P < 0.05) than Katahdin lambs during the study. The total weight gain and OD for IgA were similar between breeds (P > 0.05). Negative associations (P < 0.05) between EPG and PCV or PEC were moderate to strong for the lambs of both breeds. No association was found between EPG and IgA. In conclusion, Pelibuey lambs showed phenotypic evidence of higher resistance to natural GIN infections compared to Katahdin lambs sharing the same grazing conditions in the hot humid tropics. The most accurate phenotypic markers to identify a difference in susceptibility were EPG and PEC.

  9. Rapid adaptive divergence of life-history traits in response to abiotic stress within a natural population of a parthenogenetic nematode

    PubMed Central

    Doroszuk, Agnieszka; Wojewodzic, Marcin W; Kammenga, Jan E

    2006-01-01

    Sexual reproduction is acknowledged to facilitate adaptation to novel environments while asexual eukaryotes are often regarded as having low adaptive potential. This view has been challenged in a number of studies, but the adaptive potential of asexual populations in the field is poorly documented. We investigated the response of natural populations of the parthenogenetic nematode Acrobeloides nanus to imposed divergent selective pressures. For this purpose, we employed a replicated evolution experiment in the field. After 20 years of evolution under abiotic stress and control conditions, life-history traits were assessed in reaction norm- and reciprocal transplant experiments. Both these experiments indicated adaptive divergence within the population of A. nanus. Namely, the transplant experiment demonstrated that in the stressed soil environment, body growth rate was more reduced in the nematodes originating from the control treatment. In the reaction norm experiment, survival and reproduction were higher under test conditions corresponding to the native environment of the nematodes. The differences in the analysed traits are discussed in the context of life-history theory. Overall, our results strongly support high adaptive potential of A. nanus and suggest that population structure and distribution of asexual species is shaped by local adaptation events. PMID:17002946

  10. Flea-borne transmission model to evaluate vaccine efficacy against naturally acquired bubonic plague.

    PubMed

    Jarrett, Clayton O; Sebbane, Florent; Adamovicz, Jeffrey J; Andrews, Gerard P; Hinnebusch, B Joseph

    2004-04-01

    A flea-to-mouse transmission model was developed for use in testing new candidate vaccines for the ability to protect against flea-borne plague. The model was used to evaluate a recombinant fusion protein vaccine consisting of the Yersinia pestis F1 and V antigens. After one to three challenges with Y. pestis-infected fleas, 14 of 15 unvaccinated control mice developed plague, with an average septicemia level of 9.2 x 10(8) Y. pestis CFU/ml. None of 15 vaccinated mice developed the disease after similar challenges, and serological testing indicated that transmitted bacteria were eliminated by the immune system before extensive replication and systemic infection could occur. The transmission and development of disease in control mice correlated with the number of bites by blocked fleas but not with the total number of fleabites. The model provides a means to directly assess the efficacy of new vaccines to prevent naturally acquired bubonic plague and to study events at the vector-host interface that lead to dissemination and disease.

  11. Ocular Lesions in Red-Tailed Hawks ( Buteo jamaicensis) With Naturally Acquired West Nile Disease.

    PubMed

    Wünschmann, A; Armién, A G; Khatri, M; Martinez, L C; Willette, M; Glaser, A; Alvarez, J; Redig, P

    2017-03-01

    Ocular lesions are common in red-tailed hawks with West Nile (WN) disease. These lesions consist of pectenitis, choroidal or retinal inflammation, or retinal necrosis, but detailed investigation of the ocular lesions is lacking. Postmortem examination of the eyes of 16 red-tailed hawks with naturally acquired WN disease and 3 red-tailed hawks without WN disease was performed using histopathology, immunohistochemistry for West Nile virus (WNV) antigen, glial fibrillary acid protein, cleaved caspase-3, and the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method. Retinal lesions were classified as type I or type II lesions. Type I lesions were characterized by lymphoplasmacytic infiltrates in the subjacent choroid with degeneration limited to the outer retina (type Ia lesion) or with degeneration and necrosis of the outer retina or outer and inner retina (type Ib lesion) while retinal collapse, atrophy, and scarring were hallmarks of type II lesions. Type II retinal lesions were associated with a more pronounced choroiditis. Although not statistically significant, WNV antigen tended to be present in larger quantity in type Ib lesions. Type I lesions are considered acute while type II lesions are chronic. The development of retinal lesions was associated with the presence of an inflammatory infiltrate in the choroid. A breakdown of the blood-retina barrier is suspected to be the main route of infection of the retina. Within the retina, virus appeared to spread via both neuronal and Müller cell processes.

  12. Plasma amino acid profiles in cats with naturally acquired chronic renal failure.

    PubMed

    Goldstein, R E; Marks, S L; Cowgill, L D; Kass, P H; Rogers, Q R

    1999-01-01

    To characterize potential changes in preprandial plasma amino acid concentrations in cats with naturally acquired chronic renal failure (CRF), compared with healthy cats, and to assess potential effects of the severity of renal failure on plasma amino acid concentrations in these cats. 62 adult cats. Preprandial plasma amino acid concentrations were evaluated in 38 cats with mild, moderate, or severe CRF and in 24 apparently healthy cats. Effects of severity of renal failure, amount of dietary protein, degree of weight loss, appetite, and body condition on plasma amino acid profiles were evaluated. Cats with various stages of CRF had significantly (P< 0.05) decreased plasma concentrations of o-hydroxyproline, glutamate, proline, glycine, alanine, tyrosine, tryptophan, and arginine, and significantly increased plasma concentrations of asparagine, citrulline, ornithine, 1-methylhistidine, and 3-methylhistidine. Significant (P < 0.05) alterations in amino acid concentrations also were identified when cats with CRF were grouped by appetite or severity of renal disease. Amount of dietary protein, body condition, or degree of weight loss had no significant effect on plasma amino acid concentrations. Compared with those in healthy cats, preprandial plasma amino acid profiles in cats with mild, moderate, or severe CRF are abnormal. Despite frequency of altered plasma amino acid concentrations in cats with CRF, the magnitude of these changes is mild and of little clinical relevance. Short-term use of a commercial protein-restricted diet has no deleterious effects on plasma amino acid concentrations.

  13. Distribution of Peripheral PrPSc in Sheep with Naturally Acquired Scrapie

    PubMed Central

    Garza, María Carmen; Monzón, Marta; Marín, Belén; Badiola, Juan José; Monleón, Eva

    2014-01-01

    Accumulation of prion protein (PrPSc) in the central nervous system is the hallmark of transmissible spongiform encephalopathies. However, in some of these diseases such as scrapie or chronic wasting disease, the PrPSc can also accumulate in other tissues, particularly in the lymphoreticular system. In recent years, PrPSc in organs other than nervous and lymphoid have been described, suggesting that distribution of this protein in affected individuals may be much larger than previously thought. In the present study, 11 non-nervous/non-lymphoid organs from 16 naturally scrapie infected sheep in advanced stages of the disease were examined for the presence of PrPSc. Fourteen infected sheep were of the ARQ/ARQ PRNP genotype and 2 of the VRQ/VRQ, where the letters A, R, Q, and V represent the codes for amino-acids alanine, arginine, glutamine and valine, respectively. Adrenal gland, pancreas, heart, skin, urinary bladder and mammary gland were positive for PrPSc by immunohistochemistry and IDEXX HerdChek scrapie/BSE Antigen EIA Test in at least one animal. Lung, liver, kidney and skeletal muscle exhibited PrPSc deposits by immunohistochemistry only. To our knowledge, this is the first report regarding the presence of PrPSc in the heart, pancreas and urinary bladder in naturally acquired scrapie infections. In some other organs examined, in which PrPSc had been previously detected, PrPSc immunolabeling was observed to be associated with new structures within those organs. The results of the present study illustrate a wide dissemination of PrPSc in both ARQ/ARQ and VRQ/VRQ infected sheep, even when the involvement of the lymphoreticular system is scarce or absent, thus highlighting the role of the peripheral nervous system in the spread of PrPSc. PMID:24828439

  14. Distribution of peripheral PrP(Sc) in sheep with naturally acquired scrapie.

    PubMed

    Garza, María Carmen; Monzón, Marta; Marín, Belén; Badiola, Juan José; Monleón, Eva

    2014-01-01

    Accumulation of prion protein (PrPSc) in the central nervous system is the hallmark of transmissible spongiform encephalopathies. However, in some of these diseases such as scrapie or chronic wasting disease, the PrPSc can also accumulate in other tissues, particularly in the lymphoreticular system. In recent years, PrPSc in organs other than nervous and lymphoid have been described, suggesting that distribution of this protein in affected individuals may be much larger than previously thought. In the present study, 11 non-nervous/non-lymphoid organs from 16 naturally scrapie infected sheep in advanced stages of the disease were examined for the presence of PrPSc. Fourteen infected sheep were of the ARQ/ARQ PRNP genotype and 2 of the VRQ/VRQ, where the letters A, R, Q, and V represent the codes for amino-acids alanine, arginine, glutamine and valine, respectively. Adrenal gland, pancreas, heart, skin, urinary bladder and mammary gland were positive for PrPSc by immunohistochemistry and IDEXX HerdChek scrapie/BSE Antigen EIA Test in at least one animal. Lung, liver, kidney and skeletal muscle exhibited PrPSc deposits by immunohistochemistry only. To our knowledge, this is the first report regarding the presence of PrPSc in the heart, pancreas and urinary bladder in naturally acquired scrapie infections. In some other organs examined, in which PrPSc had been previously detected, PrPSc immunolabeling was observed to be associated with new structures within those organs. The results of the present study illustrate a wide dissemination of PrPSc in both ARQ/ARQ and VRQ/VRQ infected sheep, even when the involvement of the lymphoreticular system is scarce or absent, thus highlighting the role of the peripheral nervous system in the spread of PrPSc.

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

    PubMed

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

    2014-12-16

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

  16. Storage of a naturally acquired conditioned response is impaired in patients with cerebellar degeneration.

    PubMed

    Thieme, Andreas; Thürling, Markus; Galuba, Julia; Burciu, Roxana G; Göricke, Sophia; Beck, Andreas; Aurich, Volker; Wondzinski, Elke; Siebler, Mario; Gerwig, Marcus; Bracha, Vlastislav; Timmann, Dagmar

    2013-07-01

    Previous findings suggested that the human cerebellum is involved in the acquisition but not the long-term storage of motor associations. The finding of preserved retention in cerebellar patients was fundamentally different from animal studies which show that both acquisition and retention depends on the integrity of the cerebellum. The present study investigated whether retention had been preserved because critical regions of the cerebellum were spared. Visual threat eye-blink responses, that is, the anticipatory closure of the eyes to visual threats, have previously been found to be naturally acquired conditioned responses. Because acquisition is known to take place in very early childhood, visual threat eye-blink responses can be used to test retention in patients with adult onset cerebellar disease. Visual threat eye-blink responses were tested in 19 adult patients with cerebellar degeneration, 27 adult patients with focal cerebellar lesions due to stroke, 24 age-matched control subjects, and 31 younger control subjects. High-resolution structural magnetic resonance images were acquired in patients to perform lesion-symptom mapping. Voxel-based morphometry was performed in patients with cerebellar degeneration, and voxel-based lesion-symptom mapping in patients with focal disease. Visual threat eye-blink responses were found to be significantly reduced in patients with cerebellar degeneration. Visual threat eye-blink responses were also reduced in patients with focal disease, but to a lesser extent. Visual threat eye-blink responses declined with age. In patients with cerebellar degeneration the degree of cerebellar atrophy was positively correlated with the reduction of conditioned responses. Voxel-based morphometry showed that two main regions within the superior and inferior parts of the posterior cerebellar cortex contributed to expression of visual threat eye-blink responses bilaterally. Involvement of the more inferior parts of the posterior lobe was

  17. The effects of feeding sericea lespedeza hay on growth rate of goats naturally infected with gastrointestinal nematodes

    USDA-ARS?s Scientific Manuscript database

    Goat production is increasing in the United States due to high ethnic demand, but infection with gastrointestinal nematodes (GIN) is a major constraint to the industry. Increasing GIN resistance to chemical anthelmintics world-wide has led to the development of alternative control strategies, inclu...

  18. Systemic acquired resistance in crop protection: from nature to a chemical approach.

    PubMed

    Gozzo, Franco

    2003-07-30

    Plant natural resistance to potential parasites is regulated by two fundamental mechanisms: the "nonhost" and the "gene-for-gene" resistance, respectively. The latter is relevant when a cultivar resistant (R) gene product recognizes an avirulence gene product in the attacking pathogen and triggers an array of biochemical reactions that halt the pathogen around the site of attempted invasion. To cope with virulent pathogens, plants may benefit by some temporary immunity after a challenge triggering such an array of defense reactions, following a localized necrotizing infection as a possible consequence of a hypersensitive response (HR). This process, mediated by accumulation of endogenous salicylic acid (SA), is called systemic acquired resistance (SAR) and provides resistance, to a certain extent even against unrelated pathogens, such as viruses, bacteria, and fungi, for a relatively long-lasting period. SAR may be more potently activated in plants pretreated with chemical inducers, most of which appear to act as functional analogues of SA. This review summarizes the complex aspects of SAR as a way to prevent crop diseases by activating the plants' own natural defenses. The following outline is taken: (1) introduction through the historical insight of the phenomenon; (2) oxidative burst, which produces high levels of oxygen reactive species in a way similar to the inflammation state in animals and precedes the HR to the pathogen attack; (3) SAR as a coordinate action of several gene products leading to the expression of defenses well beyond the time and space limits of the HR; (4) jasmonic acid (JA) and ethylene as other endogenous factors mediating a different pathway of induced resistance; (5) pathogenesis related proteins (PR proteins) de novo synthesized as specific markers of SAR; (6) exogenous inducers of SAR, which include both synthetic chemicals and natural products; (7) the pathway of signal transduction between sensitization by inducers and PR expression

  19. Natural history of community-acquired methicillin-resistant Staphylococcus aureus colonization and infection in soldiers.

    PubMed

    Ellis, Michael W; Hospenthal, Duane R; Dooley, David P; Gray, Paula J; Murray, Clinton K

    2004-10-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging pathogen for which the prevalence, risk factors, and natural history are incompletely understood. In this prospective observational study, we evaluated 812 US Army soldiers to determine the prevalence of and risk factors for CA-MRSA colonization and the changes in colonization rate over time, as well as to determine the clinical significance of CA-MRSA colonization. Demographic data and swab samples from the nares for S. aureus cultures were obtained from participants at the start of their training and 8-10 weeks later. Over this time period, participants were observed prospectively to monitor for soft-tissue infections. S. aureus isolates were characterized by in vitro examination of antibiotic susceptibilities, mecA confirmation, pulsed-field gel electrophoresis, and Panton-Valentine leukocidin (PVL) gene testing. At the initial sampling, 24 of the participants (3%) were colonized with CA-MRSA, 9 of whom (38%) developed soft-tissue infections during the study period. In contrast, 229 participants (28%) were colonized with methicillin-susceptible S. aureus (MSSA), 8 (3%) of whom developed clinical infections during the same period (relative risk, 10.7; 95% confidence interval, 4.6-25.2; P<.001). At follow-up culture, the CA-MRSA colonization rate dropped to 1.6% without eradication efforts. Previous antibiotic use was a risk factor for CA-MRSA colonization at the initial sampling (P=.03). PVL genes were detected in 66% of 45 recovered CA-MRSA isolates, including all 9 clinical isolates available for analysis. Of subjects hospitalized, 5 of 6 had PVL-positive CA-MRSA infections. CA-MRSA colonization with PVL-positive strains was associated with a significant risk of soft-tissue infection, suggesting that CA-MRSA may be more virulent than MSSA. Previous antibiotic use may play a role in CA-MRSA colonization.

  20. The prevalence of naturally acquired swimming ability among children in Bangladesh: a cross sectional survey.

    PubMed

    Rahman, Aminur; Linnan, Michael; Mashreky, Saidur Rahman; Hossain, Mohammad Jahangir; Rahman, Fazlur

    2014-04-27

    Most rural homes in Bangladesh have ponds nearby to serve as household water sources. As a result children of all ages are exposed to water bodies on a daily basis. Children learn to swim early in childhood from peers and relatives in a natural process that involves play and structured learning. In a large, national injury survey in Bangladesh, the ability to swim was associated with reduced risk of drowning. This study determines the prevalence of swimming ability in children in Bangladesh as a step in assessing whether this is a potential component of a national drowning prevention program. A descriptive study design using a subset of a national sample survey determined the prevalence of naturally acquired swimming ability (NASA) reported by children of rural and urban communities in Bangladesh. A total of 2,598 households (1,999 rural and 599 urban) housing 4,336 children (2,263 male and 2,073 female) aged 5-17 years were chosen from 4 randomly selected districts using multistage random sampling. NASA was defined as the ability to cross 25 meters of water deeper than the child's height using any body movement for self-propulsion. Reported NASA was greater in males (55.6%) than females (47.9%) and among rural children (57.8%) than urban children (25.5%) for children 5-17 years. The proportion reporting NASA increased with increasing age. At age 5, 5.8% of males and 6.3% of females reported NASA, rising to 84.3% of males and 70.7% of females by age 17. By age 17, 83.1% of rural children and 57.5% of urban children reported NASA. Most children in Bangladesh report being able to swim 25 meters and learning it by middle childhood. Reported NASA is higher for males than females and for rural children than urban children. High rates of swimming appear to be achievable in the absence of pools and a swim-teaching industry. This may facilitate development of a low cost, national drowning prevention program with swimming an integral part.

  1. The prevalence of naturally acquired swimming ability among children in Bangladesh: a cross sectional survey

    PubMed Central

    2014-01-01

    Background Most rural homes in Bangladesh have ponds nearby to serve as household water sources. As a result children of all ages are exposed to water bodies on a daily basis. Children learn to swim early in childhood from peers and relatives in a natural process that involves play and structured learning. In a large, national injury survey in Bangladesh, the ability to swim was associated with reduced risk of drowning. This study determines the prevalence of swimming ability in children in Bangladesh as a step in assessing whether this is a potential component of a national drowning prevention program. Methods A descriptive study design using a subset of a national sample survey determined the prevalence of naturally acquired swimming ability (NASA) reported by children of rural and urban communities in Bangladesh. A total of 2,598 households (1,999 rural and 599 urban) housing 4,336 children (2,263 male and 2,073 female) aged 5-17 years were chosen from 4 randomly selected districts using multistage random sampling. NASA was defined as the ability to cross 25 meters of water deeper than the child’s height using any body movement for self-propulsion. Results Reported NASA was greater in males (55.6%) than females (47.9%) and among rural children (57.8%) than urban children (25.5%) for children 5-17 years. The proportion reporting NASA increased with increasing age. At age 5, 5.8% of males and 6.3% of females reported NASA, rising to 84.3% of males and 70.7% of females by age 17. By age 17, 83.1% of rural children and 57.5% of urban children reported NASA. Conclusion Most children in Bangladesh report being able to swim 25 meters and learning it by middle childhood. Reported NASA is higher for males than females and for rural children than urban children. High rates of swimming appear to be achievable in the absence of pools and a swim-teaching industry. This may facilitate development of a low cost, national drowning prevention program with swimming an integral

  2. Use of pelleted sericea lespedeza (Lespedeza cuneata) for natural control of coccidia and gastrointestinal nematodes in weaned goats.

    PubMed

    Kommuru, D S; Barker, T; Desai, S; Burke, J M; Ramsay, A; Mueller-Harvey, I; Miller, J E; Mosjidis, J A; Kamisetti, N; Terrill, T H

    2014-08-29

    Infection with Eimeria spp. (coccidia) can be devastating in goats, particularly for young, recently-weaned kids, resulting in diarrhea, dehydration, and even death. Feeding dried sericea lespedeza [SL; Lespedeza cuneata (Dum.-Cours.) G. Don.] to young goats has been reported to reduce the effects of internal parasites, including gastrointestinal nematodes (GIN) but there have been no reports of the effects of feeding this forage on Eimeria spp. in goats. Two confinement feeding experiments were completed on recently-weaned intact bucks (24 Kiko-cross, Exp. 1; 20 Spanish, Exp. 2) to determine effects of SL pellets on an established infection of GIN and coccidia. The bucks were assigned to 1 of 2 (Exp. 1) or 3 (Exp. 2) treatment groups based upon the number of Eimeria spp. oocysts per gram (OPG) of feces. In Exp. 1, the kids were fed 1 of 2 pelleted rations ad libitum; 90% SL leaf meal+10% of a liquid molasses/lignin binder mix and a commercial pellet with 12% crude protein (CP) and 24% acid detergent fiber (n=12/treatment group, 2 animals/pen). For Exp. 2, treatment groups were fed (1) 90% SL leaf meal pellets from leaves stored 3 years (n=7), (2) 90% SL pellets from leaf meal stored less than 6 months, (n=7), and the commercial pellets (n=6) ad libitum. For both trials, fecal and blood samples were taken from individual animals every 7 days for 28 days to determine OPG and GIN eggs per gram (EPG) and packed cell volume (PCV), respectively. In Exp. 2, feces were scored for consistency (1=solid pellets, 5=slurry) as an indicator of coccidiosis. In Exp. 1, EPG (P<0.001) and OPG (P<0.01) were reduced by 78.7% and 96.9%, respectively, 7 days after initiation of feeding in goats on the SL pellet diet compared with animals fed the control pellets. The OPG and EPG remained lower in treatment than control animals until the end of the trial. In Exp. 2, goats fed new and old SL leaf meal pellets had 66.2% and 79.2% lower (P<0.05) EPG and 92.2% and 91.2% lower (P<0.05) OPG

  3. Parameters affecting plant defense pathway mediated recruitment of entomopathogenic nematodes

    USDA-ARS?s Scientific Manuscript database

    Entomopathogenic nematodes are natural enemies and effective biological control agents of subterranean insect herbivores. Interactions between her bivores, plants, and entomopathogenic nematodes are mediated by plant defense pathways that can induce release of volatiles that recruit entomopathogenic...

  4. Immunological aspects of nematode parasite control in sheep.

    PubMed

    Miller, J E; Horohov, D W

    2006-04-01

    Gastrointestinal nematode parasitism is arguably the most serious constraint affecting sheep production worldwide. Economic losses are caused by decreased production, the costs of prophylaxis and treatment, and the death of the infected animals. The nematode of particular concern is Haemonchus contortus, which can cause severe blood loss resulting in anemia, anorexia, depression, loss of condition, and eventual death. The control of nematode parasites traditionally relies on anthelmintic treatment. The evolution of anthelmintic resistance in nematode populations threatens the success of drug treatment programs. Alternative strategies for control of nematode infections are being developed, and one approach is to take advantage of the host's natural or acquired immune responses, which can be used in selection programs to increase the level of resistance in the population. Vaccination can also be used to stimulate or boost the host's acquired immunity. The induction of protective resistance is dependent on the pattern of cytokine gene expression induced during infection by two defined CD4+ T-helper cell subsets, which have been designated as Th1 or Th2. Intracellular parasites most often invoke a Th1-type response, and helminth parasites a Th2-type response. Breeds of sheep resistant to infection have developed resistance over a much longer term of host-parasite relationship than genetically selected resistant lines. The immune components involved in these different responses and types of host-parasite relationships will be reviewed. The potential for using vaccines has been investigated, with variable results, for several decades. The few successes and potential new antigen candidates will also be reviewed.

  5. Natural replacement of vertically inherited lux-rib genes of Photobacterium aquimaris by horizontally acquired homologues.

    PubMed

    Urbanczyk, Henryk; Furukawa, Takashi; Yamamoto, Yuki; Dunlap, Paul V

    2012-08-01

    We report here the first instance of a complete replacement of vertically inherited luminescence genes by horizontally acquired homologues. Different strains of Photobacterium aquimaris contain homologues of the lux-rib genes that have a different evolutionary history. Strain BS1 from the Black Sea contains a vertically inherited lux-rib operon, which presumably arose in the ancestor of this species, whereas the type strain NBRC 104633(T) , from Sagami Bay, lacks the vertically inherited lux-rib operon and instead carries a complete and functional lux-rib operon acquired horizontally from a bacterium related to Photobacterium mandapamensis. The results indicate that the horizontal acquisition of the lux genes expanded the pan-genome of P. aquimaris, but it did not influence the phylogenetic divergence of this species.

  6. [The relationship between the peri-parturient period and output of nematodes eggs in naturally infected Anglo Nubiana goats in a semi-extensive system of production].

    PubMed

    Pinto, Jaqueline Maria Da S; De Oliveira, Marcos Antônio L; Alvares, Caio Tácito; Costa-Dias, Roberta; Dos Santos, Maico Henrique

    2008-09-01

    The purpose of this study was to identify the relationship between the excretion of nematodes eggs in naturally infected Anglo-Nubians breed goats under conditions of semi-extensive production system and the peri-parturient period. Were used 63 goats, with weight average 35, 05 +/- 6, 54 kg and reproductive cycle from goats. Animals were separated and two groups homogeneous as to the age and nutritional status and two groups (pregnants and nonpregnants). Faecal samples were collected weekly during the periparturient period (ended four weeks of pregnancy and the four first weeks of post-parturition) and equal dates in non-pregnants group. The group of pregnant animals showed increasing EPG (eggs per gram of faeces) in the 5th and 8th week of collection and animals not pregnant and in the 5th and 6th week. The highest counts of EPG were coincident with the highest concentration of births; there is a direct relationship between to release eggs from gastrointestinal nematodes in the female goats, near to birth.

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

    PubMed Central

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

    2014-01-01

    In their natural habitat, bacteria are consumed by bacterivorous nematodes; however, they are not simply passive preys. Here we report a defensive mechanism used by certain bacteria to mobilize nematode-trapping fungi to kill nematodes. These bacteria release urea, which triggers a lifestyle switch in the fungus Arthrobotrys oligospora from saprophytic to nematode–predatory form; this predacious form is characterized by formation of specialized cellular structures or ‘traps’. The bacteria significantly promote the elimination of nematodes by A. oligospora. Disruption of genes involved in urea transport and metabolism in A. oligospora abolishes the urea-induced trap formation. Furthermore, the urea metabolite ammonia functions as a signal molecule in the fungus to initiate the lifestyle switch to form trap structures. Our findings highlight the importance of multiple predator–prey interactions in prey defense mechanisms. PMID:25514608

  8. Sequence and genetic map of Meloidogyne hapla: A compact nematode genome for plant parasitism

    PubMed Central

    Opperman, Charles H.; Bird, David M.; Williamson, Valerie M.; Rokhsar, Dan S.; Burke, Mark; Cohn, Jonathan; Cromer, John; Diener, Steve; Gajan, Jim; Graham, Steve; Houfek, T. D.; Liu, Qingli; Mitros, Therese; Schaff, Jennifer; Schaffer, Reenah; Scholl, Elizabeth; Sosinski, Bryon R.; Thomas, Varghese P.; Windham, Eric

    2008-01-01

    We have established Meloidogyne hapla as a tractable model plant-parasitic nematode amenable to forward and reverse genetics, and we present a complete genome sequence. At 54 Mbp, M. hapla represents not only the smallest nematode genome yet completed, but also the smallest metazoan, and defines a platform to elucidate mechanisms of parasitism by what is the largest uncontrolled group of plant pathogens worldwide. The M. hapla genome encodes significantly fewer genes than does the free-living nematode Caenorhabditis elegans (most notably through a reduction of odorant receptors and other gene families), yet it has acquired horizontally from other kingdoms numerous genes suspected to be involved in adaptations to parasitism. In some cases, amplification and tandem duplication have occurred with genes suspected of being acquired horizontally and involved in parasitism of plants. Although M. hapla and C. elegans diverged >500 million years ago, many developmental and biochemical pathways, including those for dauer formation and RNAi, are conserved. Although overall genome organization is not conserved, there are areas of microsynteny that may suggest a primary biological function in nematodes for those genes in these areas. This sequence and map represent a wealth of biological information on both the nature of nematode parasitism of plants and its evolution. PMID:18809916

  9. A combination of doxycycline and ivermectin is adulticidal in dogs with naturally acquired heartworm disease (Dirofilaria immitis).

    PubMed

    Grandi, G; Quintavalla, C; Mavropoulou, A; Genchi, M; Gnudi, G; Bertoni, G; Kramer, L

    2010-05-11

    Canine heartworm disease is caused by infection with Dirofilaria immitis, a filarial nematode that resides in the pulmonary arteries and occasionally in the right heart chambers of infected dogs. Here the authors evaluated the effect of a combination of doxycycline (10 mg/kg/sid for 30 days) and ivermectin–pyrantel(6μg/kg [DOSAGE ERROR CORRECTED] of ivermectin+5mg/kg of pyrantel every 15 days for 180 days) on microfilariemia, antigenemia and parasite load at echocardiography in naturally infected dogs from an endemic region of Italy. Dogs were examined monthly for 6 months and followed-up 4 months later. One hundred percent of dogs became negative for circulating microfilariae by day 90, while 8/11 (72.7%) of dogs became antigen-negative by day 300. Of the 7 dogs that were positive for visualization of parasites at echocardiography, 6 (85.7%) became negative by day 300. Treatment was well-tolerated by all dogs. These results suggest that a combination of doxycycline and ivermectin is adulticide in dogs with D. immitis.

  10. Assessing stimulus control in natural settings: an analysis of stimuli that acquire control during training.

    PubMed

    Halle, J W; Holt, B

    1991-01-01

    When a learner is taught a new response, the stimuli that influence its display are often unknown. The presence or absence of these stimuli alters the probability of occurrence of the response. By identifying the stimuli influencing the probability of newly acquired responses, interventionists may program for their generalization more effectively and efficiently. This investigation describes the application of an operant methodology to assess functional relationships between responses and specific stimulus variables. Four young adults with moderate mental retardation were taught to include "please" as part of requests they made in school. Four environmental stimuli, present during training, were assessed for the controlling properties they acquired. Each of the four was assessed prior to and after training by presenting it in isolation (i.e., the other three were varied). If the presence of a single stimulus associated with training did not occasion "please," then pairs of stimuli were probed. The results revealed that single-stimulus probing occasioned responding by only 1 learner; paired-stimulus probing set the occasion for including "please" by 2 others. Control of the 4th learner's responding was lost before training was introduced, because he began including "please" in his requests during baseline. The implications of these results are discussed in terms of analyzing stimulus control and promoting stimulus generalization.

  11. Passive transfer of naturally acquired specific immunity against West Nile Virus to foals in a semi-feral pony herd.

    PubMed

    Wilkins, Pamela A; Glaser, Amy L; McDonnell, Sue M

    2006-01-01

    Horses naturally exposed to West Nile Virus (WNV) or vaccinated against WNV develop humoral immunity thought to be protective against development of clinical disease in exposed or infected animals. No reports evaluate the efficacy of passive transfer of naturally acquired specific WNV humoral immunity from dam to foal. The purpose of this study was to investigate passive transfer of naturally acquired immunity to WNV to foals born in a herd of semi-feral ponies, not vaccinated against WNV, in an endemic area, with many dams having seroconverted because of natural exposure. Microwell serum neutralization titers against WNV were determined in all mares and foals. Serum IgG concentration was determined in foals by serial radial immunodiffusion. Differences in IgG concentration between seropositive and seronegative foals were examined by means of the Mann-Whitney U-test. Linear regression was used to evaluate the association between mare and foal titers. Seventeen mare-foal pairs were studied; 1 foal had inadequate IgG concentration. IgG concentration was not different between seronegative and seropositive foals (P = .24). Mare and foal titers were significantly correlated in foals with adequate passive transfer of immunity (Spearman's rho = .84; P < .001); >90% of the foal's titer was explained by the mare's titer (R2 = 0.91; P < .001). Passive transfer of specific immunity to WNV is present in pony foals with adequate passive transfer of immunity born to seroconverted mares.

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

    PubMed

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

    2015-01-01

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

  13. Nematode-trapping fungi eavesdrop on nematode pheromones

    PubMed Central

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

    2013-01-01

    Summary 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 condition. Our results demonstrate that microbial predators eavesdrop on chemical communication among their metazoan prey to regulate morphogenesis, providing a striking example of predator-prey co-evolution. We anticipate that these findings will have broader implications for understanding other inter-kingdom interactions involving nematodes, which are found in almost any ecological niche on Earth. PMID:23246407

  14. Nematode-trapping fungi eavesdrop on nematode pheromones.

    PubMed

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

    2013-01-07

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

  15. Preparation of nematodes for scanning electron microscopy.

    PubMed

    Green, C D; Stone, A R; Turner, R H; Clark, S A

    1975-01-01

    Nematodes from the orders Tlyenchida and Rhabditida were fixed and processed in several different ways for examination with the scanning electron microscope (SEM). Four processes produced good preparations of fixed nematodes. Drying from acetone was the simplest of these techniques and most useful for regions of the tylenchid nematodes supported by skeletal tissue. Critical point drying, a more complicated procedure, gave good preparations, but they required special care in processing. Nematodes infiltrated with glycerol and a conducting agent were the most life-like but were difficult to examine. Specimens infiltrated with an epoxy resin looked natural and this was the most promising process tried.

  16. A Look into Students' Retention of Acquired Nature of Science Understandings

    ERIC Educational Resources Information Center

    Khishfe, Rola

    2015-01-01

    Having the learning and retention of science content and skills as a goal of scientific literacy, it is significant to study the issue of retention as it relates to teaching and learning about nature of science (NOS). Then, the purpose of this study was to investigate the development of NOS understandings of students, and the retention of these…

  17. A Look into Students' Retention of Acquired Nature of Science Understandings

    ERIC Educational Resources Information Center

    Khishfe, Rola

    2015-01-01

    Having the learning and retention of science content and skills as a goal of scientific literacy, it is significant to study the issue of retention as it relates to teaching and learning about nature of science (NOS). Then, the purpose of this study was to investigate the development of NOS understandings of students, and the retention of these…

  18. Human natural chimerism: an acquired character or a vestige of evolution?

    PubMed

    Rinkevich, B

    2001-06-01

    Analysis on five common classes of human natural chimeras (cytomictical, whole body, fetal-maternal, germ cell, and tumor chimeras) reveals that (1) they initiate only during pregnancy, (2) the most common class are chimeras which contain maternal cells, and (3) the primary mechanisms that are involved in their formation and establishment are still elusive. These classes of natural chimerism, are involved only with maladaptive phenomena such as malignancy and autoimmune diseases and without any documented benefit. A recent review has challenged the accepted dogma that the evolution of immunity is pathogen-directed and asserted that preserving individuality from littering the soma and the germline by conspecific alien cells might have been the original function of the innate immunity. Following this tenet, I propose here that human natural chimerism is a by-product of the new role evolved from primitive components of immunity to "educate" the developing embryo with the armamentarium of effector mechanisms, dedicated to purge the individual from pervasive somatic and germline variants, and is not a vestige of evolution.

  19. Acquired (dis)liking of natural cheese in different repeated exposure environment.

    PubMed

    Go, Jung-Eun; Kim, Mi-Ran; Chung, Seo-Jin

    2017-09-01

    This study investigated the development of (dis)liking of various types of natural cheese with repeated exposures among Korean young females in two environment settings. Six types of natural cheese with varying flavor and texture characteristics were selected: Brie, Emmental, Gorgonzola, Gouda, Parmigiano-Reggiano and sharp Cheddar. The subjects were randomly divided into two groups (individual evaluation vs. social interaction) and exposed to all six types of cheeses eight times for 4 weeks. The acceptance scores for these cheeses were monitored at the beginning (first taste test) and end (second taste test) of the exposure test as well as 1 month after the completion of exposure test (third taste test). The results showed that the acceptance of cheese was affected by the cheese type and the number of test trials but not by tasting environment. The acceptance levels were higher for Brie, Gouda and sharp Cheddar than for Emmental, Gorgonzola and Parmigiano-Reggiano. When the subjects were exposed to Brie, Emmental, Gouda, and sharp Cheddar repeatedly, their acceptance level increased significantly. This study demonstrated that the liking of natural cheese can occur through repeated exposure to the cheese, but with the outcome varying with the type of cheese. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Ovicidal and larvicidal activity of extracts of Opuntia ficus-indica against gastrointestinal nematodes of naturally infected sheep.

    PubMed

    Féboli, Aline; Laurentiz, Antonio C; Soares, Suelen C S; Augusto, Jeferson G; Anjos, Luciano A; Magalhães, Lizandra G; Filardi, Rosemeire S; Laurentiz, Rosangela S

    2016-08-15

    This study describes the in vitro anthelmintic activity of extracts from Opuntia ficus indica against gastrointestinal nematodes of sheep. The anthelmintic activity was evaluated by inhibition of egg hatching, larval development and larval migration assays. The residual aqueous fractions from cladodes and fruits showed higher ovicidal activity with EC50 values of 7.2mg/mL and 1.5mg/mL, respectively. The aqueous, hexane, and ethyl acetate fractions from fruits and the aqueous fraction from cladodes inhibited 100% of larval development at the lowest concentration tested (1.56mg/mL). The crude cladode and fruit ethanolic extracts inhibited larval migration and showed EC50 values of 0.74mg/mL and 0.27mg/mL, respectively. Phytochemical screening detected high concentrations of alkaloids, tannins, flavonoids, and saponins in the fruits and cladodes. The results demonstrated that O. ficus exhibits anthelmintic activity in vitro, suggesting that, beyond its nutritional potential, this plant can also be an ally for parasite control in sheep. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. The effect of supplementary feeding on the resilience and resistance of browsing Criollo kids against natural gastrointestinal nematode infections during the rainy season in tropical Mexico.

    PubMed

    Torres-Acosta, J F J; Jacobs, D E; Aguilar-Caballero, A; Sandoval-Castro, C; May-Martinez, M; Cob-Galera, L A

    2004-10-05

    The objective was to determine the effect of supplementary feeding on the resilience and resistance of Criollo kids against natural gastrointestinal nematode (GIN) infections, when browsing native vegetation during the wet season in tropical Mexico. Thirty-four 2-month old Criollo kids, raised nematode free, were included at weaning in a 22-week trial. The kids were placed into four groups. Two groups of 8 kids were offered 100g/day soybean and sorghum meal (26%:74%, respectively fresh basis) (treated/supplemented (T-S) and infected/supplemented (I-S)). Two groups remained with no supplement for the duration of the trial (infected/non-supplemented (I-NS) (n = 10) and treated/non-supplemented (T-NS) (n = 8)). Kids in groups T-S and T-NS were drenched with 0.2mg of moxidectin/kg body weight orally (Cydectin, Fort Dodge) every 28 days. Groups I-S and I-NS were naturally infected with GIN. The animals browsed native vegetation (for an average of 7h/day) together with a herd of 120 naturally infected adult goats. Cumulative live weight gain (CLWG), packed cell volume (PCV), haemoglobin (Hb), total plasma protein and plasma albumin were recorded every 14 days as measurements of resilience. Resistance parameters (faecal egg counts (FEC) and peripheral eosinophil counts (PEC)) were also measured. Bulk faecal cultures were made for each group every 28 days. Every month a new pair of tracer kids assessed the infectivity of the vegetation browsed by the animals. The T-S group had the highest CLWG, PCV and Hb compared to the other three groups (P < 0.001). The I-S and T-NS group had similar mean CLWG and PCV (P > 0.05), while the I-NS group had the poorest CLWG, PCV and Hb (P < 0.001). The PEC of supplemented kids (I-S and T-S) was higher than in the I-NS and T-NS kids (P < 0.05). No effect of supplementary feeding was found in the FEC. Tracer kids and faecal cultures showed that kids suffered mixed infections with Haemonchus contortus, Trichostrongylus colubriformis and

  2. Reactogenicity and immunogenicity of measles-rubella combined vaccine in school-entry-aged subjects with naturally acquired measles immunity.

    PubMed

    Kumagai, Takuji; Ihara, Toshiaki; Nakayama, Tetsuo; Nagata, Nobuo; Kamiya, Hitoshi

    2015-08-01

    The reintroduction of measles-rubella combined (MR) vaccination to Japan raised concerns about adverse events as well as immunogenicity related to booster immunization in subjects with naturally acquired immunity to measles or rubella. The time course of reactogenicity and antibody responses in recipients with pre-existing immunity to measles through natural infection was observed. Eighteen children aged 80-104 months received MR booster vaccination; 16 of them had had previous rubella vaccination. There were virtually no clinical reactions related to booster vaccination, and a highly significant antibody response to rubella antigen, whereas the antibody rise to measles was statistically significant but poor. Vaccination of individuals already immune is not harmful. Booster immunization to rubella for Japanese children is vitally important. © 2015 Japan Pediatric Society.

  3. Genetic basis for natural and acquired resistance to the diarylquinoline R207910 in mycobacteria.

    PubMed

    Petrella, Stephanie; Cambau, Emmanuelle; Chauffour, Aurelie; Andries, Koen; Jarlier, Vincent; Sougakoff, Wladimir

    2006-08-01

    The atpE gene encoding the subunit c of the ATP synthase of Mycobacterium tuberculosis, the target of the new diarylquinoline drug R207910, has been sequenced from in vitro mutants resistant to the drug. The previously reported mutation A63P and a new mutation, I66M, were found. The genetic diversity of atpE in 13 mycobacterial species was also investigated, revealing that the region involved in resistance to R207910 is conserved, except in Mycobacterium xenopi in which the highly conserved residue Ala63 is replaced by Met, a modification that may be associated with the natural resistance of M. xenopi to R207910.

  4. Genetic Basis for Natural and Acquired Resistance to the Diarylquinoline R207910 in Mycobacteria

    PubMed Central

    Petrella, Stephanie; Cambau, Emmanuelle; Chauffour, Aurelie; Andries, Koen; Jarlier, Vincent; Sougakoff, Wladimir

    2006-01-01

    The atpE gene encoding the subunit c of the ATP synthase of Mycobacterium tuberculosis, the target of the new diarylquinoline drug R207910, has been sequenced from in vitro mutants resistant to the drug. The previously reported mutation A63P and a new mutation, I66M, were found. The genetic diversity of atpE in 13 mycobacterial species was also investigated, revealing that the region involved in resistance to R207910 is conserved, except in Mycobacterium xenopi in which the highly conserved residue Ala63 is replaced by Met, a modification that may be associated with the natural resistance of M. xenopi to R207910. PMID:16870785

  5. BLyS inhibition eliminates primary B cells but leaves natural and acquired humoral immunity intact.

    PubMed

    Scholz, Jean L; Crowley, Jenni E; Tomayko, Mary M; Steinel, Natalie; O'Neill, Patrick J; Quinn, William J; Goenka, Radhika; Miller, Juli P; Cho, Yun Hee; Long, Vatana; Ward, Chris; Migone, Thi-Sau; Shlomchik, Mark J; Cancro, Michael P

    2008-10-07

    We have used an inhibiting antibody to determine whether preimmune versus antigen-experienced B cells differ in their requisites for BLyS, a cytokine that controls differentiation and survival. Whereas in vivo BLyS inhibition profoundly reduced naïve B cell numbers and primary immune responses, it had a markedly smaller effect on memory B cells and long-lived plasma cells, as well as secondary immune responses. There was heterogeneity within the memory pools, because IgM-bearing memory cells were sensitive to BLyS depletion whereas IgG-bearing memory cells were not, although both were more resistant than naïve cells. There was also heterogeneity within B1 pools, as splenic but not peritoneal B1 cells were diminished by anti-BLyS treatment, yet the number of natural antibody-secreting cells remained constant. Together, these findings show that memory B cells and natural antibody-secreting cells are BLyS-independent and suggest that these pools can be separately manipulated.

  6. Determination of serum organic acids in puppies with naturally acquired parvoviral enteritis

    PubMed Central

    Nappert, Germain; Dunphy, Elizabeth; Ruben, Dawn; Mann, F. A.

    2002-01-01

    The purpose of the present study was to investigate the acid-base status and the serum concentration of organic acids in puppies with naturally occurring canine parvoviral enteritis. Between July 1999 and July 2000, 25 client-owned puppies admitted to the St. Louis Animal Emergency Clinic South for treatment of enteritis caused by parvovirus infection were used in our study. Control blood samples were collected from 22 healthy puppies less than 9 months of age. Serum organic acid concentrations were quantitatively determined by HPLC. Puppies infected with parvovirus had significantly lower plasma concentrations of sodium, potassium, chloride, and bicarbonate than controls. Although serum L-lactate tended to increase in some puppies with canine parvoviral enteritis, our study demonstrated that most affected puppies developed only mild compensated metabolic acidosis. None of the affected puppies had an elevated serum D-lactate concentration at admission. PMID:11858643

  7. Plasmodium vivax Pre-Erythrocytic–Stage Antigen Discovery: Exploiting Naturally Acquired Humoral Responses

    PubMed Central

    Molina, Douglas M.; Finney, Olivia C.; Arevalo-Herrera, Myriam; Herrera, Socrates; Felgner, Philip L.; Gardner, Malcolm J.; Liang, Xiaowu; Wang, Ruobing

    2012-01-01

    The development of pre-erythrocytic Plasmodium vivax vaccines is hindered by the lack of in vitro culture systems or experimental rodent models. To help bypass these roadblocks, we exploited the fact that naturally exposed Fy− individuals who lack the Duffy blood antigen (Fy) receptor are less likely to develop blood-stage infections; therefore, they preferentially develop immune responses to pre-erythrocytic–stage parasites, whereas Fy+ individuals experience both liver- and blood-stage infections and develop immune responses to both pre-erythrocytic and erythrocytic parasites. We screened 60 endemic sera from P. vivax-exposed Fy+ or Fy− donors against a protein microarray containing 91 P. vivax proteins with P. falciparum orthologs that were up-regulated in sporozoites. Antibodies against 10 P. vivax antigens were identified in sera from P. vivax-exposed individuals but not unexposed controls. This technology has promising implications in the discovery of potential vaccine candidates against P. vivax malaria. PMID:22826492

  8. Supplementation of moist and dehydrated citrus pulp in the diets of sheep artificially and naturally infected with gastrointestinal nematodes on the parasitological parameters and performance.

    PubMed

    Nordi, E C P; Costa, R L D; David, C M G; Parren, G A E; Freitas, A C B; Lameirinha, L P; Katiki, L M; Bueno, M S; Quirino, C R; Gama, P E; Bizzo, H R; Chagas, A C S

    2014-10-15

    The inclusion of industrial byproducts such as citrus pulp in the composition of animal diets has been widely recommended due to sustainability aspects and their high level of carbohydrates. Limonene is found in citrus pulp and has been described elsewhere as a major compound of citrus essential oils with excellent anthelmintic activity. The objective of this study was to evaluate the parasitological parameters of lambs artificially infected (Experiment 1) with Haemonchus contortus and naturally infected (Experiment 2) by gastrointestinal nematodes, fed diets with dehydrated citrus pulp or silage of moist orange pulp. Both experiments had three treatments (C: control, DP: diet+dehydrated citrus pulp, and MP: diet+silage of moist orange pulp). The diets were isoproteic (11% crude protein) and the concentrate was corrected every 14 days according to animal weight. Parasitological parameters were evaluated for both experiments each 14 days (body weight, body condition; fecal egg counts-FEC, egg hatch assay-EHA, coproculture, and packed cell volume-PCV). Analysis of variance (GLM of the SAS software) was performed with repeated measures in time, and the means were compared by the Tukey test. Gas chromatography with mass spectrometry was used to detect constituents of dry or moist citrus pulp. Dehydrated citrus pulp had 0.02% essential oil (major compounds were 85.9% limonene and 7.6% valencene). Moist orange pulp contained 1.5% essential oil (major compounds were 65.5% limonene and 31.2% alpha- and gamma-terpineol). In both experiments, the weight gain among the treatments was similar (p>0.05) demonstrating that both moist and dehydrated orange pulp can be used to replace corn kernels to feed infected lambs. The supplementation with orange pulp did not decrease natural or artificial infections of gastrointestinal nematodes according to the FEC results (p>0.05). However, PCV increased from animals fed dehydrated and moist pulp in natural infection (Experiment 2, p<0

  9. Efficacy of selamectin against experimentally induced and naturally acquired ascarid (Toxocara canis and Toxascaris leonina) infections in dogs.

    PubMed

    McTier, T L; Siedek, E M; Clemence, R G; Wren, J A; Bowman, D D; Hellmann, K; Holbert, M S; Murphy, M G; Young, D R; Cruthers, L R; Smith, D G; Shanks, D J; Rowan, T G; Jernigan, A D

    2000-08-23

    The efficacy of selamectin against adult ascarids was evaluated in eight controlled and masked studies in dogs. Three laboratory studies evaluated selamectin against experimentally induced infections of Toxocara canis; three laboratory studies evaluated selamectin against naturally acquired infections of T. canis; one laboratory study evaluated selamectin against naturally acquired infections of both T. canis and Toxascaris leonina; one field study evaluated selamectin against naturally acquired infections of ascarids (T. canis and/or T. leonina) in dogs presented as veterinary patients. Selamectin was administered topically to the skin of dogs in unit doses designed to deliver a minimum of 6mgkg(-1) (range, 6-12mgkg(-1)). In all studies, dogs were allocated randomly to treatment assignments (selamectin or vehicle control in laboratory studies: selamectin or reference product in the field study) on the basis of pretreatment fecal egg counts. For induced infections, there were significant reductions in geometric mean numbers of adult T. canis after a single application of selamectin (93.9-98.1%, P=0.0001), after two monthly applications (> or =88.3%, P< or =0.0001), and after three monthly applications (100%, P< or =0.0002). In the natural infection laboratory studies, when selamectin was administered twice at an interval of 30 days, the percentage reductions in geometric mean numbers of adult T. canis at necropsy were 84.6, 91.3, and 97.9%, and when selamectin was administered on days 0, 14, and 30, the percentage reductions were 91.1 and 97.6%. Geometric mean fecal T. canis egg counts were reduced by > or =92.9% (P< or =0.0067) at the end of the studies. In the field study, geometric mean fecal ascarid egg counts were reduced by 89.5 and 95. 5% (P=0.0001) for 14 and 30 days, respectively, after a single treatment with selamectin, and by 94.0% (P=0.0001) 30 days after the second treatment with selamectin. These reductions compared favorably with the egg count

  10. The efficacy of trichlorphon and naphthalophos against multiple anthelmintic-resistant nematodes of naturally infected sheep in Argentina.

    PubMed

    Fiel, César; Guzmán, Maricel; Steffan, Pedro; Rodriguez, Edgardo; Prieto, Olegario; Bhushan, Chandra

    2011-08-01

    An anthelmintic efficacy trial was conducted in sheep harbouring anthelmintic-resistant worms in Argentina. Seventy lambs were selected from a flock that had been grazed on pastures infected with trichostrongyles previously shown to be resistant to the main anthelmintic groups. Lambs were allocated to comparable groups of ten animals each and treated with trichlorphon (50 mg/kg body weight (b.w.) orally); naphthalophos (50 mg/kg b.w. orally); ivermectin (0.2 mg/kg b.w. subcutaneously); fenbendazole (5 mg/kg b.w. orally); levamisole (8 mg/kg b.w. subcutaneously) and closantel (10 mg/kg b.w. orally). There was also an untreated group. The dose selection was based on manufacturer's recommendations.Faecal samples were collected 0 and 10 days post treatment to estimate efficacy (faecal egg count reduction). Six animals from each group were necropsied at day 10 for enumeration/identification of worms from the abomasum, small and large intestines to determine the absolute efficacy of each agent (controlled efficacy test). Trichlorphon and naphthalophos were effective (> 99 %) against Haemonchus contortus (p < 0.05).Naphthalophos also showed efficacy against Trichostrongylus axei (99.3 %), Teladorsagia circumcincta (97.8 %), Trichostrongylus colubriformis (99.2 %), Cooperia punctata/curticei/pectinata (90.4 %), Nematodirus spathiger (89.2 %) and Oesophagostomum venulosum/columbianum (93.7 %). Fenbendazole and levamisole showed efficacy (> 95 %) against all nematodes except T. colubriformis. The efficacy of ivermectin was low against H. contortus (23 %) and Cooperia spp. (46.3 %). Closantel showed low efficacy against T. axei (64.4 %), H. contortus (80.6 %) and T. colubriformis (59.5 %).When anthelmintic resistance is widespread, trichlorphon treatment is appropriate if H. contortus is present; however, naphthalophos represents an effective therapeutic alternative for incorporation into worm control programmes.

  11. Naturally acquired bovine besnoitiosis: histological and immunohistochemical findings in acute, subacute, and chronic disease.

    PubMed

    Langenmayer, M C; Gollnick, N S; Majzoub-Altweck, M; Scharr, J C; Schares, G; Hermanns, W

    2015-05-01

    The pathogenesis of bovine besnoitiosis, a disease of increasing concern within Europe, is still incompletely understood. In this study, disease progression after natural infection with the causative apicomplexan Besnoitia besnoiti was monitored in histological skin sections of 5 individual female cattle over time. High-frequency skin sampling of 2 cattle with mild and 2 with severe acute, subacute, and chronic besnoitiosis, as well as from 1 animal during subclinical disease, enabled documentation from the beginning of the disease. Skin sections were stained with hematoxylin and eosin and Giemsa, periodic acid-Schiff reaction, and anti-Besnoitia immunohistochemistry. In all 4 clinically affected animals, tachyzoite-like endozoites could be detected for the first time by immunohistochemistry, and tissue cyst evolution was monitored. Besnoitiosis-associated lesions were not detected in the animal showing the subclinical course. Because of the inconsistency of the nomenclature of Besnoitia tissue cyst layers in the literature, a new nomenclature for B. besnoiti cyst wall layers is proposed: tissue cysts consist of a hypertrophied host cell with enlarged nuclei, an intracytoplasmic parasitophorous vacuole with bradyzoites, a sometimes vacuolated inner cyst wall, and an outer cyst wall in more developed cysts. Inner and outer cyst walls can be readily distinguished by using special stains. In 1 animal, extracystic B. besnoiti zoites were immunohistochemically detected during the chronic stage. At necropsy, the 2 severely affected cows displayed large numbers of B. besnoiti cysts in a variety of tissues, including the corium of the claws, contributing mainly to the development of chronic laminitis in these 2 cases.

  12. Validity of the Enzyme-linked Immunoelectrotransfer Blot (EITB) for naturally acquired porcine cysticercosis

    PubMed Central

    Jayashi, César M.; Gonzalez, Armando E.; Neyra, Ricardo Castillo; Rodríguez, Silvia; García, Hector H.; Lightowlers, Marshall W.

    2017-01-01

    The Enzyme-linked Immunoelectrotransfer Blot (EITB) has been used widely as a screening test for Taenia solium cysticercosis in swine. However, the relation between seropositivity and infection in pig populations from endemic areas has not been well defined. The aim of this study is to relate EITB seropositivity with infection and infection burden, analyse the trade-off between sensitivity and specificity with various cut-off points for the EITB assay, and finally describe the serology changes in a cohort of rural pigs raised under natural conditions. A group of 107 pigs that were used as controls during a vaccination field trial in Peru was our study population. The prevalence of porcine cysticercosis determined by necropsy examination was 16.82% (18/107) in these animals. Using EITB reactivity to ≥ 1 band as a cut-off point for the assay, the sensitivity was 88.89% (65.29-98.62, 95% CI) and the specificity was 48.31% (37.59-59.16, 95% CI). Comparing other cut-off points, involving up to as many as 7 reactive bands, a reactivity of ≥ 3 bands provided the best trade-offs in sensitivity and specificity. Using this cut-off point for the assay, the sensitivity was 77.77% (52.36 - 93.59, 95% CI) and the specificity was 76.40% (66.22 - 84.76, 95% CI). A significant association was found between cyst counts over 100 cysts and reactivity to ≥ 3 bands in the EITB assay (Fisher’s exact test, p<0.05). The results of this study suggest that the use of the EITB assay to study porcine cysticercosis may require setting different cut-offs under field and experimental conditions, and depending upon the objective of the screening process. PMID:24183647

  13. Effect of selenium yeast supplementation on naturally acquired parasitic infection in ewes.

    PubMed

    Hooper, Kathryn J; Bobe, Gerd; Vorachek, William R; Bishop-Stewart, Janell K; Mosher, Wayne D; Pirelli, Gene J; Kent, Michael L; Hall, Jean A

    2014-12-01

    Gastrointestinal parasites cause substantial economic losses in pasture-based sheep production systems. Supranutritional organic selenium (Se) supplementation may be beneficial because it improves immune responses to pathogens. To evaluate the effect of Se-yeast supplementation on gastrointestinal parasite load, 30 ewes per treatment group were drenched weekly with no Se, 4.9 mg Se/week as Se yeast (maximum FDA-allowed concentration), or supranutritional concentrations of Se yeast (14.7 and 24.5 mg Se/week) starting early fall for 85 weeks. Fecal samples were collected at weeks 63, 66, 78, and 84 and counted for total trichostrongyle-type eggs and Haemonchus contortus eggs (in samples with ≥200 trichostrongyle eggs/g feces). During breeding season (fall), ewes were kept on pasture; ewes receiving 24.5 mg Se/week had lower fecal trichostrongyle egg counts (93 ± 40 eggs/g feces) compared with ewes receiving no Se (537 ± 257 eggs/g feces; P = 0.007) or ewes receiving 4.9 mg Se/week as Se yeast (398 ± 208 eggs/g feces; P = 0.03). In winter, fecal trichostrongyle egg counts decreased, and group differences were not apparent. During lambing season (spring), ewes were kept in the barn and fecal trichostrongyle egg counts increased, although no group differences were observed. However, none of the ewes receiving supranutritional Se yeast, and with trichostrongyle egg counts ≥200 eggs/g of feces, but four of the ewes receiving lower Se dosages had H. contortus egg counts ≥1,000 eggs/g feces (P = 0.04). Our results suggest that supranutritional Se-yeast supplementation may enhance resistance to naturally occurring H. contortus gastrointestinal parasitism in sheep.

  14. Environmentally-acquired bacteria influence microbial diversity and natural innate immune responses at gut surfaces.

    PubMed

    Mulder, Imke E; Schmidt, Bettina; Stokes, Christopher R; Lewis, Marie; Bailey, Mick; Aminov, Rustam I; Prosser, James I; Gill, Bhupinder P; Pluske, John R; Mayer, Claus-Dieter; Musk, Corran C; Kelly, Denise

    2009-11-20

    Early microbial colonization of the gut reduces the incidence of infectious, inflammatory and autoimmune diseases. Recent population studies reveal that childhood hygiene is a significant risk factor for development of inflammatory bowel disease, thereby reinforcing the hygiene hypothesis and the potential importance of microbial colonization during early life. The extent to which early-life environment impacts on microbial diversity of the adult gut and subsequent immune processes has not been comprehensively investigated thus far. We addressed this important question using the pig as a model to evaluate the impact of early-life environment on microbe/host gut interactions during development. Genetically-related piglets were housed in either indoor or outdoor environments or in experimental isolators. Analysis of over 3,000 16S rRNA sequences revealed major differences in mucosa-adherent microbial diversity in the ileum of adult pigs attributable to differences in early-life environment. Pigs housed in a natural outdoor environment showed a dominance of Firmicutes, in particular Lactobacillus, whereas animals housed in a hygienic indoor environment had reduced Lactobacillus and higher numbers of potentially pathogenic phylotypes. Our analysis revealed a strong negative correlation between the abundance of Firmicutes and pathogenic bacterial populations in the gut. These differences were exaggerated in animals housed in experimental isolators. Affymetrix microarray technology and Real-time Polymerase Chain Reaction revealed significant gut-specific gene responses also related to early-life environment. Significantly, indoor-housed pigs displayed increased expression of Type 1 interferon genes, Major Histocompatibility Complex class I and several chemokines. Gene Ontology and pathway analysis further confirmed these results. Early-life environment significantly affects both microbial composition of the adult gut and mucosal innate immune function. We observed that a

  15. Validity of the Enzyme-linked Immunoelectrotransfer Blot (EITB) for naturally acquired porcine cysticercosis.

    PubMed

    Jayashi, César M; Gonzalez, Armando E; Castillo Neyra, Ricardo; Rodríguez, Silvia; García, Hector H; Lightowlers, Marshall W

    2014-01-17

    The Enzyme-linked Immunoelectrotransfer Blot (EITB) has been used widely as a screening test for Taenia solium cysticercosis in swine. However, the relation between seropositivity and infection in pig populations from endemic areas has not been well defined. The aim of this study is to relate EITB seropositivity with infection and infection burden, analyse the trade-off between sensitivity and specificity with various cut-off points for the EITB assay, and finally describe the serology changes in a cohort of rural pigs raised under natural conditions. A group of 107 pigs that were used as controls during a vaccination field trial in Peru was our study population. The prevalence of porcine cysticercosis determined by necropsy examination was 16.82% (18/107) in these animals. Using EITB reactivity to ≥ 1 band as a cut-off point for the assay, the sensitivity was 88.89% (65.29-98.62, 95% CI) and the specificity was 48.31% (37.59-59.16, 95% CI). Comparing other cut-off points, involving up to as many as 7 reactive bands, a reactivity of ≥ 3 bands provided the best trade-offs in sensitivity and specificity. Using this cut-off point for the assay, the sensitivity was 77.77% (52.36-93.59, 95% CI) and the specificity was 76.40% (66.22-84.76, 95% CI). A significant association was found between cyst counts over 100 cysts and reactivity to ≥ 3 bands in the EITB assay (Fisher's exact test, p<0.05). The results of this study suggest that the use of the EITB assay to study porcine cysticercosis may require setting different cut-offs under field and experimental conditions, and depending upon the objective of the screening process. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Nematode Indicators of Organic Enrichment

    PubMed Central

    Ferris, Howard; Bongers, Tom

    2006-01-01

    The organisms of the soil food web, dependent on resources from plants or on amendment from other sources, respond characteristically to enrichment of their environment by organic matter. Primary consumers of the incoming substrate, including bacteria, fungi, plant-feeding nematodes, annelids, and some microarthropods, are entry-level indicators of enrichment. However, the quantification of abundance and biomass of this diverse group, as an indicator of resource status, requires a plethora of extraction and assessment techniques. Soluble organic compounds are absorbed by bacteria and fungi, while fungi also degrade more recalcitrant sources. These organisms are potential indicators of the nature of incoming substrate, but current methods of biomass determination do not reliably indicate their community composition. Guilds of nematodes that feed on bacteria (e.g., Rhabditidae, Panagrolaimidae) and fungi (e.g., Aphelenchidae, Aphelenchoididae) are responsive to changes in abundance of their food. Through direct herbivory, plant-feeding nematodes (e.g., many species of Tylenchina) also contribute to food web resources. Thus, analysis of the nematode community of a single sample provides indication of carbon flow through an important herbivore channel and through channels mediated by bacteria and fungi. Some nematode guilds are more responsive than others to resource enrichment. Generally, those bacterivores with short lifecycles and high reproductive potential (e.g., Rhabditidae) most closely mirror the bloom of bacteria or respond most rapidly to active plant growth. The feeding habits of some groups remain unclear. For example, nematodes of the Tylenchidae may constitute 30% or more of the individuals in a soil sample; further study is necessary to determine which resource channels they portray and the appropriate level of taxonomic resolution for this group. A graphic representation of the relative biomass of bacterivorous, fungivorous, and herbivorous nematodes

  17. The effects of feeding sericea lespedeza hay on growth rate of goats naturally infected with gastrointestinal nematodes.

    PubMed

    Moore, D A; Terrill, T H; Kouakou, B; Shaik, S A; Mosjidis, J A; Miller, J E; Vanguru, M; Kannan, G; Burke, J M

    2008-09-01

    Goat production is increasing in the United States due to high ethnic demand, but infection with gastrointestinal nematode (GIN) parasites is a major constraint to the industry. Increasing GIN resistance to chemical anthelmintics worldwide has led to the development of alternative control strategies, including use of forages containing condensed tannins (CT). An experiment was designed using infected and dewormed male kids (Kiko x Spanish, 6 mo old, 18.9 +/- 3.25 kg) fed diets containing 25% concentrate and either 75% sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours.) G. Don], a high CT forage (87 to 181 g of CT/kg), or 75% bermudagrass [BG; Cynodon dactylon (L.) Pers.] hay (n = 10/treatment). The kids were weighed every 14 d, and fecal and blood samples were taken weekly for fecal egg counts and packed cell volume determination, respectively. Fecal cultures were processed every 14 d to determine CT effect on larval development. At slaughter, adult GIN were collected from the abomasum and small intestines for counting and speciation. Blood samples were also analyzed for plasma urea-N, and ruminal VFA and pH were determined. The infected SL-fed kids had consistently lower (P < 0.05) fecal egg counts than the infected BG goats throughout the trial and greater (P < 0.05) packed cell volume beginning by d 77. Average daily gain was greater (P < 0.001) in kids fed SL- than BG-based diets, regardless of infection status (104.3 +/- 5.0 and 75.5 +/- 4.8 g/d, respectively). Total VFA and acetate concentrations were greater (P < 0.001) in the BG- than in SL-fed goats, whereas propionate levels were unaffected by diet. Acetate:propionate ratio (P = 0.01) and plasma urea-N (P = 0.03) levels were greater in BG-fed goats, whereas rumen pH was greater (P < 0.001) in the SL-fed goats. Feeding SL hay can reduce GIN infection levels and increase performance of goats compared with BG hay.

  18. Clinical efficacy of selamectin in the treatment of naturally acquired infection of sucking lice (Linognathus setosus) in dogs.

    PubMed

    Gunnarsson, Lotta; Christensson, Dan; Palmér, Eleonor

    2005-01-01

    A clinical study was performed in 21 dogs to evaluate the efficacy of selamectin for the treatment of naturally acquired infection of sucking lice (Linognathus setosus [L.setosus]) in dogs. Each dog was randomly assigned to one of two treatment groups. One group was treated with selamectin applied topically at a mean dosage of 7.9 mg/kg. The other group was treated with permethrin applied topically at a mean dosage of 85.7 mg/kg. At day 42 posttreatment, all animals remaining in the study (10 treated with selamectin and six with permethrin) were clear of lice. In both groups, the reduction in lice counts from pretreatment values to day 42 was statistically significant at P< or =0.0001. Selamectin applied topically appeared to be effective against L. setosus infection in dogs.

  19. Nematodes (Rhabditida: Steinernematidae and Heterorhabditidae)

    USDA-ARS?s Scientific Manuscript database

    Nematodes are roundworms in the phylum Nematoda. Although most are free-living, some nematodes are parasites of plants, humans, or livestock. Entomopathogenic nematodes in the families Steinernematidae & Heterorhabditidae only parasitize insects. These nematodes are used as environmentally friend...

  20. Role of major histocompatibility complex class II in resistance of mice to naturally acquired infection with Syphacia obvelata

    NASA Technical Reports Server (NTRS)

    Stewart, Patricia W.; Chapes, Stephen K.

    2003-01-01

    Genetics plays a substantial role in host resistance in many host-parasite interactions. We examined the prevalence of naturally acquired infection with Syphacia obvelata in a number of mouse strains housed in a non-barrier facility. These mice, which included cross-bred and congenic, inbred strains on various genetic backgrounds, differ in the loci for the immune function genes--major histocompatibility complex class II (MHCII), toll-like receptor 4 (Tlr4), and solute carrier family 11, member 1 (Slc11a1)--which allowed comparisons of the impact of these genes on resistance to pinworm infection. Male and female mice of various ages were sampled over an 18-month period; infection was determined by use of the cellophane tape test. Results indicated that mice that were MHCII+/+ had a significantly lower prevalence of infection than did mice that were MHCII-/-. Differences were not seen between male and female mice. Although MHCII+/+ mice had an age-associated decrease in infection prevalence, such decrease was not seen in MHCII-/- mice. In contrast, infection prevalence in mice with the normal Tlr4 gene (Tlr4(LPS-n/LPS-n)) gene did not differ significantly compared with that in mice that were homozygous for either the point mutation (Tlr4(LPS-d/LPS-d)) or deletion (Tlr4(LPS-del/LPS-del)) of that gene. Likewise, the presence (Sle11a1r/r) or absence (Slc11a1s/s) of functional alleles for Slc11a1 had no effect on the prevalence of infection with S. obvelata. In conclusion, presence of MHCII, but not Tlr4 or Slc11a1 significantly influences prevalence of naturally acquired infection with S. obvelata. These data justify further comprehensive analyses of the immune components that are involved in pinworm resistance.

  1. Enhancement of natural and acquired immunity by Lactobacillus rhamnosus (HN001), Lactobacillus acidophilus (HN017) and Bifidobacterium lactis (HN019).

    PubMed

    Gill, H S; Rutherfurd, K J; Prasad, J; Gopal, P K

    2000-02-01

    Consumption of lactic acid bacteria (LAB) has been suggested to confer a range of health benefits including stimulation of the immune system and increased resistance to malignancy and infectious illness. In the present study, the effects of feeding Lactobacillus rhamnosus (HN001, DR20), Lactobacillus acidophilus (HN017) and Bifidobacterium lactis (HN019, DR10) on in vivo and in vitro indices of natural and acquired immunity in healthy mice were examined. Mice were fed daily with L. rhamnosus, L. acidophilus or B. lactis (10(9) colony forming units) and their immune function was assessed on day 10 or day 28. Supplementation with L. rhamnosus, L. acidophilus or B. lactis resulted in a significant increase in the phagocytic activity of peripheral blood leucocytes and peritoneal macrophages compared with the control mice. The proliferative responses of spleen cells to concanavalin A (a T-cell mitogen) and lipopolysaccharide (a B-cell mitogen) were also significantly enhanced in mice given different LAB. Spleen cells from mice given L. rhamnosus, L. acidophilus or B. lactis also produced significantly higher amounts of interferon-gamma in response to stimulation with concanavalin A than cells from the control mice. LAB feeding had no significant effect on interleukin-4 production by spleen cells or on the percentages of CD4+, CD8+ and CD40+ cells in the blood. The serum antibody responses to orally and systemically administered antigens were also significantly enhanced by supplementation with L. rhamnosus, L. acidophilus or B. lactis. Together, these results suggest that supplementation of the diet with L. rhamnosus (HN001), L. acidophilus (HN017) or B. lactis (HN019) is able to enhance several indices of natural and acquired immunity in healthy mice.

  2. Role of major histocompatibility complex class II in resistance of mice to naturally acquired infection with Syphacia obvelata

    NASA Technical Reports Server (NTRS)

    Stewart, Patricia W.; Chapes, Stephen K.

    2003-01-01

    Genetics plays a substantial role in host resistance in many host-parasite interactions. We examined the prevalence of naturally acquired infection with Syphacia obvelata in a number of mouse strains housed in a non-barrier facility. These mice, which included cross-bred and congenic, inbred strains on various genetic backgrounds, differ in the loci for the immune function genes--major histocompatibility complex class II (MHCII), toll-like receptor 4 (Tlr4), and solute carrier family 11, member 1 (Slc11a1)--which allowed comparisons of the impact of these genes on resistance to pinworm infection. Male and female mice of various ages were sampled over an 18-month period; infection was determined by use of the cellophane tape test. Results indicated that mice that were MHCII+/+ had a significantly lower prevalence of infection than did mice that were MHCII-/-. Differences were not seen between male and female mice. Although MHCII+/+ mice had an age-associated decrease in infection prevalence, such decrease was not seen in MHCII-/- mice. In contrast, infection prevalence in mice with the normal Tlr4 gene (Tlr4(LPS-n/LPS-n)) gene did not differ significantly compared with that in mice that were homozygous for either the point mutation (Tlr4(LPS-d/LPS-d)) or deletion (Tlr4(LPS-del/LPS-del)) of that gene. Likewise, the presence (Sle11a1r/r) or absence (Slc11a1s/s) of functional alleles for Slc11a1 had no effect on the prevalence of infection with S. obvelata. In conclusion, presence of MHCII, but not Tlr4 or Slc11a1 significantly influences prevalence of naturally acquired infection with S. obvelata. These data justify further comprehensive analyses of the immune components that are involved in pinworm resistance.

  3. Therapeutic immunomodulators from nematode parasites.

    PubMed

    Harnett, William; Harnett, Margaret M

    2008-06-19

    There has been an alarming increase in the incidence of autoimmune and allergic diseases in Western countries in the past few decades. However, in countries endemic for parasitic helminth infections, such diseases remain relatively rare. Hence, it has been hypothesised that helminths may protect against the development of autoimmunity and allergy. This article reviews the evidence supporting this idea with respect to helminths of the phylum Nematoda (nematodes), considering data from human studies and animal models of inflammatory disease. The nature and mode of action of nematode-derived molecules with immunomodulatory properties are considered, and their therapeutic efficacy in models of autoimmunity and allergy described. The recent and future use of nematodes and their products in treating human disease are also discussed.

  4. How do humans affect wildlife nematodes?

    USGS Publications Warehouse

    Weinstein, Sara B.; Lafferty, Kevin D.

    2015-01-01

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

  5. How do humans affect wildlife nematodes?

    PubMed

    Weinstein, Sara B; Lafferty, Kevin D

    2015-05-01

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

  6. Significance of anti-CarLA salivary IgA antibody in first grazing season cattle naturally infected with gastrointestinal nematodes.

    PubMed

    Merlin, Aurélie; Shaw, Richard; Chauvin, Alain; Bareille, Nathalie; Chartier, Christophe

    2017-08-30

    A carbohydrate larval surface antigen (CarLA) present on infective larvae of all trichostrongylid nematodes is a target antigen for host immunoglobulins (Ig). Levels of anti-CarLA salivary IgA antibody (CarLA-IgA) have been shown to be correlated to the level of protective immunity to GIN in sheep and deer but no information is available in cattle. The first objective of this study was to assess the pattern of CarLA-IgA response in 7 groups (G1-G7) of first grazing season cattle (FGSC) naturally infected with gastrointestinal nematodes. The second objective was to assess the phenotypic correlations between CarLA-IgA level, 3 parasitological indicators (faecal egg count-FEC, pepsinogen level, serum anti-O. ostertagi IgG antibody level-OstertagiaIgG), a clinical indicator (diarrhea score) and average daily weight gain (ADWG). Overall, CarLA-IgA response gradually increased over grazing season and showed large variations in speed and magnitude both between and within groups. Based on the mean group CarLA-IgA response pattern, the 7 groups could be allocated to 3 different classes: (i) 'Late High' class characterized by a high response at housing (G1 and G2); (ii) 'Low' class with a low response over time (G3, G4 and G5); and (iii) 'Early' class with an high initial then stable response (G6 and G7). This classification was consistent with the grazing management practices. In the 'Late High' class, the mean CarLA-IgA at housing was 6.05units/mL and negatively correlated with FEC while no correlation was seen with the other indicators nor ADWG. In the 'Low' class, CarLA response at housing was low (1.95units/mL) and mainly positively correlated with OstertagiaIgG. In the 'Early' class, mean CarLA-IgA ranged from 1.32 to 1.86units/mL during the grazing season and positive correlations were seen with parasitological and clinical indicators. These results suggest that, according to the intensity of larval challenge occurring during the first grazing season, Car

  7. Nematode burdens and immunological responses following natural challenge in Romney lambs selectively bred for low or high faecal worm egg count.

    PubMed

    Bisset, S A; Vlassoff, A; Douch, P G; Jonas, W E; West, C J; Green, R S

    1996-02-01

    Breeding lines of Romney sheep, selected as lambs for consistently low or high faecal nematode egg count (FEC) following periods of natural challenge, have been maintained at Wallaceville for some years. In order to determine the extent to which FECs in low and high genotypes reflected their ability to resist the establishment of gastro-intestinal nematode burdens, we investigated the infection status and immune responses in 8- to 9-month-old progeny of selected rams from low and high FEC breeding lines following a period of grazing without anthelmintic treatment in autumn/early winter. In each of the 2 years of the study, outcross male progeny of the two lowest FEC (LFEC) (i.e. most 'resistant') and two highest FEC (HFEC) (i.e. most 'susceptible') rams from the divergent lines were slaughtered shortly after autumn/early winter FECs had been analysed. Post-mortem worm counts and examination of intestinal histology were then undertaken. Blood samples collected before slaughter in the second year of the study were assayed to measure serum levels of Trichostrongylus colubriformis-specific antibody and immunoglobulins (IgG1 and IgM), and numbers of circulating eosinophils. Overall, correlations between pre-slaughter FEC and total trichostrongyle burdens in the lambs proved to be very high (0.91 and 0.85, respectively, for the 2 years studied). In the first year, LFEC lambs, which were shedding only 28.6% as many strongyle eggs as their HFEC counterparts at slaughter, were found to harbour 37.6% as many adult trichostrongyle worms, while in the second year, LFEC lambs, which were shedding 16.1% as many strongyle eggs as their HFEC counterparts at slaughter, were found to harbour 33.5% as many adult trichostrongyle worms. Results, particularly in the second year, confirmed that significantly fewer worms of most of the important abomasal and small intestinal nematode species which infest lambs in New Zealand (i.e. Haemonchus contortus, Ostertagia circumcincta, Cooperia

  8. The Dynamic Relationship Between Clinical Symptomatology and Viral Shedding in Naturally Acquired Seasonal and Pandemic Influenza Virus Infections

    PubMed Central

    Ip, Dennis K. M.; Lau, Lincoln L. H.; Chan, Kwok-Hung; Fang, Vicky J.; Leung, Gabriel M.; Peiris, Malik J. S.; Cowling, Benjamin J.

    2016-01-01

    Background. Although the pattern of viral shedding over time has been documented in volunteer challenge studies, understanding of the relationship between clinical symptomatology and viral shedding in naturally acquired influenza infections in humans remains limited. Methods. In a community-based study in Hong Kong from 2008 to 2014, we followed up initially healthy individuals and identified 224 secondary cases of natural influenza virus infection in the household setting. We examined the dynamic relationship between patterns of clinical symptomatology and viral shedding as quantified using reverse transcription polymerase chain reaction and viral culture in 127 cases with a clinical picture of acute respiratory infection. Results. Viral shedding in influenza A virus infections peaked on the first 1–2 days of clinical illness, and decreased gradually to undetectable levels by day 6–7, matching closely with the dynamics of clinical illness. Viral shedding in influenza B virus infections rose up to 2 days prior to symptom onset and persisted for 6–7 days after onset with a bimodal pattern. Conclusions. Our results suggest that while clinical illness profiles may serve as a proxy for clinical infectiousness in influenza A virus infections, patients may potentially be infectious even before symptom onset or after clinical improvement in influenza B virus infections. PMID:26518469

  9. A Naturally-Occurring Histone Acetyltransferase Inhibitor Derived from Garcinia indica Impairs Newly Acquired and Reactivated Fear Memories

    PubMed Central

    Maddox, Stephanie A.; Watts, Casey S.; Doyère, Valérie; Schafe, Glenn E.

    2013-01-01

    The study of the cellular and molecular mechanisms underlying the consolidation and reconsolidation of traumatic fear memories has progressed rapidly in recent years, yet few compounds have emerged that are readily useful in a clinical setting for the treatment of anxiety disorders such as post-traumatic stress disorder (PTSD). Here, we use a combination of biochemical, behavioral, and neurophysiological methods to systematically investigate the ability of garcinol, a naturally-occurring histone acetyltransferase (HAT) inhibitor derived from the rind of the fruit of the Kokum tree (Garcina indica), to disrupt the consolidation and reconsolidation of Pavlovian fear conditioning, a widely studied rodent model of PTSD. We show that local infusion of garcinol into the rat lateral amygdala (LA) impairs the training and retrieval-related acetylation of histone H3 in the LA. Further, we show that either intra-LA or systemic administration of garcinol within a narrow window after either fear conditioning or fear memory retrieval significantly impairs the consolidation and reconsolidation of a Pavlovian fear memory and associated neural plasticity in the LA. Our findings suggest that a naturally-occurring compound derived from the diet that regulates chromatin function may be useful in the treatment of newly acquired or recently reactivated traumatic memories. PMID:23349897

  10. Influence of protein supplementation on the resistance and resilience on young hair sheep naturally infected with gastrointestinal nematodes during rainy and dry seasons.

    PubMed

    Louvandini, H; Veloso, C F M; Paludo, G R; Dell'Porto, A; Gennari, S M; McManus, C M

    2006-04-15

    Thirty, 4-month-old entire Santa Ines lambs were grazed on an Andropogon gayanus pasture, during a 34-week period (rainy season weeks 0-20 and dry season weeks 21-34) and allocated in two treatment groups (n = 15) each with different protein supplementation: high protein (HP-19% CP) and low protein (LP-11% CP). These were subdivided into those receiving anthelmintic treatment (c) (n = 7) and without anthelmintic treatment (i) (n = 8). The objective was to evaluate the effects of supplementation with protein on resistance and resilience to natural helminth infection of hair breed lambs. Lamb weight, blood collection and faecal egg counts (FEC) were carried out monthly. The lambs were slaughtered after 34 weeks, when worm burdens, worm length and eosinophil cell counts were taken. The sheep on treatments HPc and HPi were heavier in live weight than those from LPi and LPc (P < 0.05) at the end of the rainy period. The HPc group finished heavier (P < 0.05) than the other groups in the dry season, which had no significant differences between them. The predominant species of nematode found was T. colubriformis followed by H. contortus, Trichuris globulosa and Moniezia expansa. Animals on HPi had lower FEC than LPi (P < 0.05). The number of worms was lower for both HP groups (P < 0.05) with worm length shorter in the HPc group (P < 0.05) compared with all other groups. The number of eosinophils was higher in animals in the LPi group, which also showed anaemia and lower plasma urea at the end of the dry season. Diet supplementation with high protein was able to improve resilience and resistance to natural infection by endoparasites during the rainy season. In the dry season there was a decrease in both of these traits, which were intimately linked to the quality of available forage under tropical conditions.

  11. Microbiota from Rhabditis regina may alter nematode entomopathogenicity.

    PubMed

    Jiménez-Cortés, Jesús Guillermo; Canales-Lazcano, Jorge; Lara-Reyes, Nancy; Rosenblueth, Mónica; Martínez-Romero, Esperanza; Contreras-Garduño, Jorge

    2016-11-01

    Here we report the presence of the entomopathogenic nematode Rhabditis (Rhabditoides) regina affecting white grubs (Phyllophaga sp. and Anomala sp.) in Mexico and R. regina-associated bacteria. Bioassays were performed to test the entomopathogenic capacity of dauer and L2 and L3 (combined) larval stages. Furthermore, we determined the diversity of bacteria from laboratory nematodes cultivated for 2 years (dauer and L2-L3 larvae) and from field nematodes (dauer and L2-L3 larvae) in addition to the virulence in Galleria mellonella larvae of some bacterial species from both laboratory and field nematodes. Dauer and non-dauer larvae of R. regina killed G. mellonella. Bacteria such as Serratia sp. (isolated from field nematodes) and Klebsiella sp. (isolated from larvae of laboratory and field nematodes) may explain R. regina entomopathogenic capabilities. Different bacteria were found in nematodes after subculturing in the laboratory suggesting that R. regina may acquire bacteria in different environments. However, there were some consistently found bacteria from laboratory and field nematodes such as Pseudochrobactrum sp., Comamonas sp., Alcaligenes sp., Klebsiella sp., Acinetobacter sp., and Leucobacter sp. that may constitute the nematode microbiome. Results showed that some bacteria contributing to entomopathogenicity may be lost in the laboratory representing a disadvantage when nematodes are cultivated to be used for biological control.

  12. Optimal vaccination and bednet maintenance for the control of malaria in a region with naturally acquired immunity.

    PubMed

    Prosper, Olivia; Ruktanonchai, Nick; Martcheva, Maia

    2014-07-21

    Following over two decades of research, the malaria vaccine candidate RTS,S has reached the final stages of vaccine trials, demonstrating an efficacy of roughly 50% in young children. Regions with high malaria prevalence tend to have high levels of naturally acquired immunity (NAI) to severe malaria; NAI is caused by repeated exposure to infectious bites and results in large asymptomatic populations. To address concerns about how these vaccines will perform in regions with existing NAI, we developed a simple malaria model incorporating vaccination and NAI. Typically, if the basic reproduction number (R0) for malaria is greater than unity, the disease will persist; otherwise, the disease will become extinct. However, analysis of this model revealed that NAI, compounded by a subpopulation with only partial protection to malaria, may render vaccination efforts ineffective and potentially detrimental to malaria control, by increasing R0 and increasing the likelihood of malaria persistence even when R0<1. The likelihood of this scenario increases when non-immune infected individuals are treated disproportionately compared with partially immune individuals - a plausible scenario since partially immune individuals are more likely to be asymptomatically infected. Consequently, we argue that active case-detection of asymptomatic infections is a critical component of an effective malaria control program. We then investigated optimal vaccination and bednet control programs under two endemic settings with varying levels of naturally acquired immunity: a typical setting under which prevalence decays when R0<1, and a setting in which subthreshold endemic equilibria exist. A qualitative comparison of the optimal control results under the first setting revealed that the optimal policy differs depending on whether the goal is to reduce total morbidity, or to reduce clinical infections. Furthermore, this comparison dictates that control programs should place less effort in

  13. Detection and comparison of nitric oxide in clinically normal horses and those with naturally acquired small intestinal strangulation obstruction.

    PubMed Central

    Mirza, M H; Oliver, J L; Seahorn, T L; Hosgood, G; Moore, R M

    1999-01-01

    The purpose of this study was to determine whether nitric oxide (NO) is present in clinically normal horses under basal conditions and if it increases secondary to naturally acquired small intestinal strangulation obstruction. Thirty-one horses were used; 20 horses with naturally acquired small intestinal strangulation obstruction and 11 clinically normal horses with no signs of gastrointestinal tract disease. Jugular venous blood, abdominal fluid, and urine were collected for NO quantification. Plasma, abdominal fluid, and urine were stored at -70 degrees C until analyzed for NO using a chemiluminescent method. Biopsy specimens collected from the affected jejunal segment, during anesthesia or after immediately after euthanasia, or from the midjejunum of control horses, were divided into subsections for fixation in zinc formalin and cryopreservation in OCT gel. Nicotinamide adenine dinucleotide phosphate (reduced) (NADPH) diaphorase histochemical stains were performed on cryopreserved tissues and inducible nitric oxide synthase (iNOS) and nitrotyrosine immunohistochemical stains were performed on formalin-fixed, paraffin-embedded tissues. There were significantly greater plasma and abdominal fluid NO concentrations in affected horses as compared with controls, but there were no significant differences between horses for urine NO concentrations. There was a significant decrease in NADPH diaphorase stain in mucosal epithelium, vasculature, and leukocytes, and in submucosal plexi in affected horses compared with control horses. There was a significant increase in iNOS staining in mucosal and submucosal leukocytes and in mucosal leukocyte nitrotyrosine staining of the affected compared with control horses. Endothelial NOS and neuronal NOS are present under basal conditions in the jejunum of horses and probably mediate physiologic or cytoprotective effects. Plasma and abdominal fluid, but not urine, NO concentrations increase subsequent to small intestinal strangulation

  14. Otitis-prone Children Have Immunologic Deficiencies in Naturally Acquired Nasopharyngeal Mucosal Antibody Response after Streptococcus pneumoniae Colonization.

    PubMed

    Xu, Qingfu; Casey, Janet R; Newman, Emily; Pichichero, Michael E

    2016-01-01

    Acute otitis media (AOM) is the most common pediatric bacterial infection, and stringently defined otitis-prone (sOP) children have immunologic deficiencies. We recently found that nasopharyngeal (NP) colonization by Streptococcus pneumoniae (Spn) elicits a NP mucosal antibody response to vaccine candidate pneumococcal proteins that correlate with protection from AOM in non-sOP (NOP) children. Here, we sought to determine if sOP children experience significantly higher colonization rates with Spn than NOP children, develop lower naturally acquired NP mucosal antibody responses to those same pneumococcal proteins after colonization by Spn, and suffer greater frequency of AOM as a consequence. NP samples were collected from 130 NOP and 45 sOP children during 270 healthy visits and 201 AOM visits between 6 and 24 months of age. Spn were identified by standard culture. NP mucosal IgG and IgA levels to vaccine candidate proteins pneumococcal histidine triad protein D, pneumococcal choline binding protein A (PcpA) and pneumolysin D1 were measured by quantitative enzyme-linked immunosorbent assay. sOP children had significantly higher colonization frequency by Spn (P < 0.0001) and significantly lower IgG and IgA levels to all 3 vaccine candidate proteins studied compared with NOP children (all P values <0.05) except IgG to Ply D1 (P = 0.31). Spn colonization in NOP children led to 2-fold to 5-fold increase in mucosal IgG and IgA levels to all 3 proteins (all P values <0.01), whereas Spn colonization in sOP children generally failed to elicit antibody responses (all P values >0.05). PcpA was unique in inducing significant increases in mucosal IgA (P = 0.02). When high mucosal IgG levels to all 3 proteins and IgA to PcpA were measured, they correlated with reduced AOM in sOP children. sOP children experience significantly higher colonization rates with Spn, develop lower naturally acquired NP mucosal antibody responses to pneumococcal vaccine candidate proteins pneumococcal

  15. Memory CD8+ T cells from naturally-acquired primary dengue virus infection are highly cross-reactive

    PubMed Central

    Friberg, Heather; Burns, Lynne; Woda, Marcia; Kalayanarooj, Siripen; Endy, Timothy P.; Stephens, Henry A.F.; Green, Sharone; Rothman, Alan L.; Mathew, Anuja

    2010-01-01

    Cross-reactive memory T cells induced by primary infection with one of the four serotypes of dengue virus (DENV) are hypothesized to play an immunopathological role in secondary heterologous DENV infection. To define the T cell response to heterologous serotypes, we isolated HLA-A*1101-restricted epitope-specific CD8+ T cell lines from primary DENV-immune donors. Cell lines exhibited marked cross-reactivity towards peptide variants representing the four DENV serotypes in tetramer binding and functional assays. Many clones responded similarly to homologous and heterologous serotypes with striking cross-reactivity between the DENV-1 and DENV-3 epitope variants. In vitro-stimulated T cell lines consistently revealed a hierarchical induction of MIP-1β > degranulation > TNFα > IFNγ, which depended on the concentration of agonistic peptide. Phosphoflow assays demonstrated peptide dose-dependent phosphorylation of ERK1/2, which correlated with cytolysis, degranulation, and induction of TNFα and IFNγ but not MIP-1β production. This is the first study to demonstrate significant DENV serotype-cross-reactivity of CD8+ T cells after naturally-acquired primary infection. We also demonstrate qualitatively different T cell receptor signaling after stimulation with homologous and heterologous peptides. Our data support a model whereby the order of sequential DENV infections influences the immune response to secondary heterologous DENV infection, contributing to varying disease outcomes. PMID:20421879

  16. Memory CD8+ T cells from naturally acquired primary dengue virus infection are highly cross-reactive.

    PubMed

    Friberg, Heather; Burns, Lynne; Woda, Marcia; Kalayanarooj, Siripen; Endy, Timothy P; Stephens, Henry A F; Green, Sharone; Rothman, Alan L; Mathew, Anuja

    2011-01-01

    Cross-reactive memory T cells induced by primary infection with one of the four serotypes of dengue virus (DENV) are hypothesized to have an immunopathological function in secondary heterologous DENV infection. To define the T-cell response to heterologous serotypes, we isolated HLA-A(*)1101-restricted epitope-specific CD8(+) T-cell lines from primary DENV-immune donors. Cell lines exhibited marked cross-reactivity toward peptide variants representing the four DENV serotypes in tetramer binding and functional assays. Many clones responded similarly to homologous and heterologous serotypes with striking cross-reactivity between the DENV-1 and DENV-3 epitope variants. In vitro-stimulated T-cell lines consistently revealed a hierarchical induction of MIP-1β>degranulation>tumor necrosis factor α (TNFα)>interferon-γ (IFNγ), which depended on the concentration of agonistic peptide. Phosphoflow assays showed peptide dose-dependent phosphorylation of ERK1/2, which correlated with cytolysis, degranulation, and induction of TNFα and IFNγ, but not MIP-1β production. This is the first study to show significant DENV serotype-cross-reactivity of CD8(+) T cells after naturally acquired primary infection. We also show qualitatively different T-cell receptor signaling after stimulation with homologous and heterologous peptides. Our data support a model whereby the order of sequential DENV infections influences the immune response to secondary heterologous DENV infection, contributing to varying disease outcomes.

  17. Evaluation of a commercially available hyperimmune plasma product for prevention of naturally acquired pneumonia caused by Rhodococcus equi in foals.

    PubMed

    Giguère, Steeve; Gaskin, Jack M; Miller, Corey; Bowman, James L

    2002-01-01

    To determine efficacy of a commercially available hyperimmune plasma product for prevention of naturally acquired pneumonia caused by Rhodococcus equi in foals. Randomized clinical trial. 165 foals. Foals were randomly assigned to 1 of 2 groups (hyperimmune plasma or nontreated controls). Foals with failure of passive transfer (FPT) of immunity were treated with hyperimmune plasma and evaluated as a third group. Foals that received plasma were given 950 ml between 1 and 10 days of age and between 30 and 50 days of age. A tracheobronchial aspirate was obtained from foals with clinical signs of respiratory tract disease for bacteriologic culture. A significant difference in incidence of pneumonia caused by R equi in foals with adequate passive transfer was not detected between foals that received plasma (19.1%) and nontreated foals (30%). Of 13 foals without FPT that received plasma and developed pneumonia caused by R equi, 12 developed disease prior to administration of the second dose of hyperimmune plasma. Incidence of undifferentiated pneumonia of all causes was not different between groups. Intravenous administration of the commercially available hyperimmune plasma was safe, and the product contained high concentrations of anti-R equi antibodies. However, within this limited foal population, the difference in incidence of pneumonia caused by R equi observed between foals that received plasma and control foals was not significant.

  18. Efficacy of albendazole, levamisole and ivermectin against gastro-intestinal nematodes in naturally infected goats at the National Semi-arid Resources Research Institute, Serere, Uganda.

    PubMed

    Byaruhanga, C; Okwee-Acai, J

    2013-07-01

    A study was conducted between April and July, 2011 to determine and compare the efficacy of albendazole (ABZ), levamisole (LVM) and ivermectin (IVM) against gastrointestinal nematodes in naturally infected Mubende and Boer crossbred goats at the National Semi-arid Resources Research Institute in Serere, Uganda. Forty Mubende goats and 31 Boer crosses were each blocked by age and sex and randomly assigned to four groups. The first group of each breed served as the untreated control, the second was treated with albendazole (5mg/kg BW), the third with levamisole hydrochloride and oxyclozanide (7.5 and 15 mg/kg BW) and the fourth with ivermectin (0.2mg/kg BW). Each group included 7-11 animals. Treatments were administered with doses of goats in albendazole and ivermectin, and doses of sheep in levamisole, as recommended by the manufacturers. In the treated groups, goats received anthelmintics basing on individual weights. Fecal egg counts, expressed as eggs per gram and larval cultures were done on day zero before treatment and on day 13 after anthelmintic treatment. Efficacy for each anthelmintic was determined by the Fecal Egg Count Reduction Test (FECRT). In Mubende goats, ABZ, LVM, and IVM reduced FEC by 28.5%, 91%, and 98%, respectively. In Boer crosses, ABZ, LVM, and IVM reduced FEC by 11%, 84.88% and 78.47%, respectively. At a 95% CI, only IVM was more effective in Mubende goats than Boer crosses (t=2.564, p<0.05). This may indicate occurrence of anthelmintic resistance in the goat farming sector in Uganda. Further studies need to be done to clarify the state of efficacy of the commonly used anthelmintics covering different agro ecological zones and species of animals in Uganda. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. The activity of albendazole against adult and larval gastrointestinal nematodes in naturally infected calves in the Netherlands.

    PubMed

    Borgsteede, F H

    1979-10-15

    The activity of albendazole against gastrointestinal helminths in naturally infected calves in the Netherlands was tested. The calves were in their first grazing season and kept in two groups of ten. One of these groups was grazed alternately with sheep. Five out of each group were drenched with albendazole (7.5 mg/kg) on the day they were housed (November 1). Before and 2, 14, and 28 days after treatment individual faecal samples were taken from all calves and larval cultures were made. Ten calves, six treated and four untreated, were killed for post mortem studies 14 days after treatment. The remaining calves were slaughtered 14 days later. The drug was highly effective in reducing the egg output, measured as the number of larvae cultured per gram of faeces. Compared with the untreated calves, the reduction was more than 99% two days after treatment, 100% at 14 days, and 99% after 28 days. It was shown that egg output 28 days after treatment came from worms which had developed from arrested larvae of Ostertagia ostertagi that had survived treatment. Post mortem results showed an efficacy of 100% against adult O. ostertagi, of almost 100% against Trichostrongylus axei, and 100% against adult and larval Cooperia oncophora. Twenty-eight days after treatment, the reduction of arrested early fourth stages of O. ostertagi was 85% in comparison with the untreated calves. Apparently less effect was found against Trichuris ovis at the given dose rate.

  20. Horizontal gene transfer of microbial cellulases into nematode genomes is associated with functional assimilation and gene turnover

    PubMed Central

    2011-01-01

    Background Natural acquisition of novel genes from other organisms by horizontal or lateral gene transfer is well established for microorganisms. There is now growing evidence that horizontal gene transfer also plays important roles in the evolution of eukaryotes. Genome-sequencing and EST projects of plant and animal associated nematodes such as Brugia, Meloidogyne, Bursaphelenchus and Pristionchus indicate horizontal gene transfer as a key adaptation towards parasitism and pathogenicity. However, little is known about the functional activity and evolutionary longevity of genes acquired by horizontal gene transfer and the mechanisms favoring such processes. Results We examine the transfer of cellulase genes to the free-living and beetle-associated nematode Pristionchus pacificus, for which detailed phylogenetic knowledge is available, to address predictions by evolutionary theory for successful gene transfer. We used transcriptomics in seven Pristionchus species and three other related diplogastrid nematodes with a well-defined phylogenetic framework to study the evolution of ancestral cellulase genes acquired by horizontal gene transfer. We performed intra-species, inter-species and inter-genic analysis by comparing the transcriptomes of these ten species and tested for cellulase activity in each species. Species with cellulase genes in their transcriptome always exhibited cellulase activity indicating functional integration into the host's genome and biology. The phylogenetic profile of cellulase genes was congruent with the species phylogeny demonstrating gene longevity. Cellulase genes show notable turnover with elevated birth and death rates. Comparison by sequencing of three selected cellulase genes in 24 natural isolates of Pristionchus pacificus suggests these high evolutionary dynamics to be associated with copy number variations and positive selection. Conclusion We could demonstrate functional integration of acquired cellulase genes into the nematode

  1. SOME ASPECTS OF THE NATURAL CONTROL OF PLANT PARASITIC NEMATODES IN SOIL UNDER BROAD BEAN VICIA FABA L. CULTIVATED IN CROP ROTATION AND LONG-TERM MONOCULTURE.

    PubMed

    Skwiercz, A T; Damszel, M; Stefanovska, T; Rychcik, B

    2015-01-01

    Observations on population density of plant parasitic nematodes occurring in rhizosphere of broad bean cultivated in the crop rotation and long-term monoculture were performed during 2013-2014. 13 species were observed: Trichodorus primitivus, T. viruliferus, Paratrichodorus pachydermus, Criconema annuliferum, Paratylenchus projectus, Bitylenchus dubius, Merlinius brevidens, Pratylenchus fallax, P. flakkensis, P. neglectus, Heterodera triffolii, H. goettingiana, and Ditylenchus dipsaci. In monoculture plots 70-80% of eggs inside Heterodera cysts were colonized by pathogenic fungi (v.s. 50-62% of cysts from crop rotation). 12-18% of specimens of Pratylenchus species were colonized by the nematode-pathogenic bacteria: Bacillus penetrans.

  2. Detection and comparison of nitric oxide in clinically healthy horses and those with naturally acquired strangulating large colon volvulus

    PubMed Central

    2005-01-01

    Abstract The objective of the study was to determine whether nitric oxide (NO) is present in clinically healthy horses (control) under basal conditions, and if it increases secondary to naturally acquired strangulating large colon volvulus (affected). Eleven affected horses and 10 controls were studied. Jugular venous blood, abdominal fluid, and urine were collected. The NO concentrations were standardized to the creatinine concentration in the respective samples. A biopsy specimen collected from the large colon pelvic flexure at surgery was divided into subsections for processing for inducible nitric synthase (iNOS) and nitrotyrosine (NT) immunohistochemical staining and reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemical staining. There were no significant differences in plasma, abdominal fluid, or urine NO concentrations between affected and control horses. There was a significant decrease in submucosal arteriolar and venular endothelium, submucosal plexus, mucosal leukocyte, mucosal and musclaris vasculature, and myenteric plexus NADPH diaphorase staining in affected versus control horses. There was a significant increase in iNOS staining in mucosal leukocytes and vasculature in affected versus control horses. Other than a greater number of positively stained mucosal leukocytes in affected horses, there were no significant differences between affected and control horses for NT staining. The presence of NADPH diaphorase staining in the endothelium and submucosal neurons suggests endothelial and neuronal NOS are present under basal conditions in the large colon of horses. Increased iNOS and NT staining in mucosal leukocytes of affected horses suggests involvement of the NO pathway in large colon volvulus. The reasons for the lack of a significant difference in plasma, abdominal fluid, and urine NO concentrations between affected and control horses are unknown. PMID:15971674

  3. Lack of renewal effect in extinction of naturally acquired conditioned eyeblink responses, but possible dependency on physical context.

    PubMed

    Claassen, J; Mazilescu, L; Thieme, A; Bracha, V; Timmann, D

    2016-01-01

    Context dependency of extinction is well known and has extensively been studied in fear conditioning, but has rarely been assessed in eyeblink conditioning. One way to demonstrate context dependency of extinction is the renewal effect. ABA paradigms are most commonly used to show the renewal effect of extinguished learned fear: if acquisition takes place in context A, and extinction takes place in context B (extinction phase), learned responses will recover in subsequent extinction trials presented in context A (renewal phase). The renewal effect of the visual threat eyeblink response (VTER), a conditioned eyeblink response, which is naturally acquired in early infancy, was examined in a total of 48 young and healthy participants with two experiments using an ABA paradigm. Twenty paired trials were performed in context A (baseline trials), followed by 50 extinction trials in context B (extinction phase) and 50 extinction trials in context A (renewal phase). In 24 participants, contexts A and B were two different rooms, and in the other 24 participants, two different background colors (orange and blue) and noises were used. To rule out spontaneous recovery, an AAA design was used for comparison. There were significant effects of extinction in both experiments. No significant renewal effects were observed. In experiment 2, however, extinction was significantly less using orange background during extinction compared to the blue background. The present findings suggest that extinction of conditioned eyeblinks depends on the physical context. Findings add to the animal literature that context can play a role in the acquisition of classically conditioned eyeblink responses. Future studies, however, need to be performed to confirm the present findings. Lack of renewal effect may be explained by the highly overlearned character of the VTER.

  4. The Nature of Small Business. Unit 2. Level 3. Instructor Guide. PACE: Program for Acquiring Competence in Entrepreneurship. Third Edition. Research & Development Series No. 303-02.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This instructor guide for a unit on the nature of small business in the PACE (Program for Acquiring Competence in Entrepreneurship) curriculum includes the full text of the student module and lesson plans, instructional suggestions, and other teacher resources. The competencies that are incorporated into this module are at Level 3 of…

  5. Ex Vivo Generated Natural Killer Cells Acquire Typical Natural Killer Receptors and Display a Cytotoxic Gene Expression Profile Similar to Peripheral Blood Natural Killer Cells

    PubMed Central

    Lehmann, Dorit; Spanholtz, Jan; Osl, Markus; Tordoir, Marleen; Lipnik, Karoline; Bilban, Martin; Schlechta, Bernhard; Dolstra, Harry

    2012-01-01

    Ex vivo differentiation systems of natural killer (NK) cells from CD34+ hematopoietic stem cells are of potential importance for adjuvant immunotherapy of cancer. Here, we analyzed ex vivo differentiation of NK cells from cord blood-derived CD34+ stem cells by gene expression profiling, real-time RT-PCR, flow cytometry, and functional analysis. Additionally, we compared the identified characteristics to peripheral blood (PB) CD56bright and CD56dim NK cells. The data show sequential expression of CD56 and the CD94 and NKG2 receptor chains during ex vivo NK cell development, resulting finally in the expression of a range of genes with partial characteristics of CD56bright and CD56dim NK cells from PB. Expression of characteristic NK cell receptors and cytotoxic genes was mainly found within the predominant ex vivo generated population of NKG2A+ NK cells, indicating the importance of NKG2A expression during NK cell differentiation and maturation. Furthermore, despite distinct phenotypic characteristics, the detailed analysis of cytolytic genes expressed within the ex vivo differentiated NK cells revealed a pattern close to CD56dim NK cells. In line with this finding, ex vivo generated NK cells displayed potent cytotoxicity. This supports that the ex vivo differentiation system faithfully reproduces major steps of the differentiation of NK cells from their progenitors, constitutes an excellent model to study NK cell differentiation, and is valuable to generate large-scale NK cells appropriate for immunotherapy. PMID:22571679

  6. Ex vivo generated natural killer cells acquire typical natural killer receptors and display a cytotoxic gene expression profile similar to peripheral blood natural killer cells.

    PubMed

    Lehmann, Dorit; Spanholtz, Jan; Osl, Markus; Tordoir, Marleen; Lipnik, Karoline; Bilban, Martin; Schlechta, Bernhard; Dolstra, Harry; Hofer, Erhard

    2012-11-01

    Ex vivo differentiation systems of natural killer (NK) cells from CD34+ hematopoietic stem cells are of potential importance for adjuvant immunotherapy of cancer. Here, we analyzed ex vivo differentiation of NK cells from cord blood-derived CD34+ stem cells by gene expression profiling, real-time RT-PCR, flow cytometry, and functional analysis. Additionally, we compared the identified characteristics to peripheral blood (PB) CD56(bright) and CD56(dim) NK cells. The data show sequential expression of CD56 and the CD94 and NKG2 receptor chains during ex vivo NK cell development, resulting finally in the expression of a range of genes with partial characteristics of CD56(bright) and CD56(dim) NK cells from PB. Expression of characteristic NK cell receptors and cytotoxic genes was mainly found within the predominant ex vivo generated population of NKG2A+ NK cells, indicating the importance of NKG2A expression during NK cell differentiation and maturation. Furthermore, despite distinct phenotypic characteristics, the detailed analysis of cytolytic genes expressed within the ex vivo differentiated NK cells revealed a pattern close to CD56(dim) NK cells. In line with this finding, ex vivo generated NK cells displayed potent cytotoxicity. This supports that the ex vivo differentiation system faithfully reproduces major steps of the differentiation of NK cells from their progenitors, constitutes an excellent model to study NK cell differentiation, and is valuable to generate large-scale NK cells appropriate for immunotherapy.

  7. Entomopathogenic nematodes and insect management

    USDA-ARS?s Scientific Manuscript database

    Entomopathogenic nematodes (genera Heterorhabditis, Steinernema, and Neosteinernema) are used as bioinsecticides. The nematodes are ubiquitous and have been isolated in soil of every continent except Antarctica. The nematodes kill insects through a mutualism with a bacterium (Photorhabdus spp. or ...

  8. Anthelmintic activity of Artemisia annua L. extracts in vitro and the effect of an aqueous extract and artemisinin in sheep naturally infected with gastrointestinal nematodes.

    PubMed

    Cala, Aida C; Ferreira, Jorge F S; Chagas, Ana Carolina S; Gonzalez, Javier M; Rodrigues, Rodney A F; Foglio, Mary Ann; Oliveira, Marcia C S; Sousa, Ilza M O; Magalhães, Pedro M; Barioni Júnior, Waldomiro

    2014-06-01

    There is no effective natural alternative control for gastrointestinal nematodes (GIN) of small ruminants, with Haemonchus contortus being the most economically important GIN. Despite frequent reports of multidrug-resistant GIN, there is no new commercial anthelmintic to substitute failing ones. Although trematocidal activity of artemisinin analogs has been reported in sheep, neither artemisinin nor its plant source (Artemisia annua) has been evaluated for anthelmintic activity in ruminants. This study evaluated the anthelmintic activity of A. annua crude extracts in vitro and compared the most effective extract with artemisinin in sheep naturally infected with H. contortus. A. annua leaves extracted with water, aqueous 0.1% sodium bicarbonate, dichloromethane, and ethanol were evaluated in vitro by the egg hatch test (EHT) and with the bicarbonate extract only for the larval development test (LDT) using H. contortus. The A. annua water, sodium bicarbonate (SBE), ethanol, and dichloromethane extracts tested in vitro contained 0.3, 0.6, 4.4, and 9.8% of artemisinin, respectively. The sodium bicarbonate extract resulted in the lowest LC99 in the EHT (1.27 μg/mL) and in a LC99 of 23.8 μg/mL in the LDT. Following in vitro results, the SBE (2 g/kg body weight (BW)) and artemisinin (100 mg/kg BW) were evaluated as a single oral dose in naturally infected Santa Inês sheep. Speciation from stool cultures established that 84-91% of GIN were H. contortus, 8.4-15.6 % were Trichostrongylus sp., and 0.3-0.7% were Oesophagostomum sp. Packed-cell volume and eggs per gram (EPG) of feces were used to test treatment efficacy. The SBE tested in vivo contained no artemisinin, but had a high antioxidant capacity of 2,295 μmol of Trolox equivalents/g. Sheep dosed with artemisinin had maximum feces concentrations 24 h after treatment (126.5 μg/g artemisinin), which sharply decreased at 36 h. By day 15, only levamisole-treated sheep had a significant decrease of 97% in EPG

  9. Experimental Evolution with Caenorhabditis Nematodes

    PubMed Central

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

    2017-01-01

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

  10. Distribution and evolution of glycoside hydrolase family 45 cellulases in nematodes and fungi

    PubMed Central

    2014-01-01

    Background Horizontal gene transfer (HGT) has been suggested as the mechanism by which various plant parasitic nematode species have obtained genes important in parasitism. In particular, cellulase genes have been acquired by plant parasitic nematodes that allow them to digest plant cell walls. Unlike the typical glycoside hydrolase (GH) family 5 cellulase genes which are found in several nematode species from the order Tylenchida, members of the GH45 cellulase have only been identified in a cluster including the families Parasitaphelenchidae (with the pinewood nematode Bursaphelenchus xylophilus) and Aphelenchoididae, and their origins remain unknown. Results In order to investigate the distribution and evolution of GH45 cellulase genes in nematodes and fungi we performed a wide ranging screen for novel putative GH45 sequences. This revealed that the sequences are widespread mainly in Ascomycetous fungi and have so far been found in a single major nematode lineage. Close relationships between the sequences from nematodes and fungi were found through our phylogenetic analyses. An intron position is shared by sequences from Bursaphelenchus nematodes and several Ascomycetous fungal species. Conclusions The close phylogenetic relationships and conserved gene structure between the sequences from nematodes and fungi strongly supports the hypothesis that nematode GH45 cellulase genes were acquired via HGT from fungi. The rapid duplication and turnover of these genes within Bursaphelenchus genomes demonstrate that useful sequences acquired via HGT can become established in the genomes of recipient organisms and may open novel niches for these organisms to exploit. PMID:24690293

  11. Distribution and evolution of glycoside hydrolase family 45 cellulases in nematodes and fungi.

    PubMed

    Palomares-Rius, Juan E; Hirooka, Yuuri; Tsai, Isheng J; Masuya, Hayato; Hino, Akina; Kanzaki, Natsumi; Jones, John T; Kikuchi, Taisei

    2014-04-01

    Horizontal gene transfer (HGT) has been suggested as the mechanism by which various plant parasitic nematode species have obtained genes important in parasitism. In particular, cellulase genes have been acquired by plant parasitic nematodes that allow them to digest plant cell walls. Unlike the typical glycoside hydrolase (GH) family 5 cellulase genes which are found in several nematode species from the order Tylenchida, members of the GH45 cellulase have only been identified in a cluster including the families Parasitaphelenchidae (with the pinewood nematode Bursaphelenchus xylophilus) and Aphelenchoididae, and their origins remain unknown. In order to investigate the distribution and evolution of GH45 cellulase genes in nematodes and fungi we performed a wide ranging screen for novel putative GH45 sequences. This revealed that the sequences are widespread mainly in Ascomycetous fungi and have so far been found in a single major nematode lineage. Close relationships between the sequences from nematodes and fungi were found through our phylogenetic analyses. An intron position is shared by sequences from Bursaphelenchus nematodes and several Ascomycetous fungal species. The close phylogenetic relationships and conserved gene structure between the sequences from nematodes and fungi strongly supports the hypothesis that nematode GH45 cellulase genes were acquired via HGT from fungi. The rapid duplication and turnover of these genes within Bursaphelenchus genomes demonstrate that useful sequences acquired via HGT can become established in the genomes of recipient organisms and may open novel niches for these organisms to exploit.

  12. The Basic Nature of Ethical Problems Experienced by Persons with Acquired Immunodeficiency Syndrome: Implications for Nursing Ethics Education and Practice.

    ERIC Educational Resources Information Center

    Cameron, Miriam E.; And Others

    1993-01-01

    Twenty-five persons with acquired immunodeficiency syndrome (AIDS) described and validated 100 ethical problems that are experienced by people with AIDS from 3 levels of ethical inquiry: descriptive ethics, normative ethics, and metaethics. Findings suggest strategies for improving nursing ethics education. (JOW)

  13. The Basic Nature of Ethical Problems Experienced by Persons with Acquired Immunodeficiency Syndrome: Implications for Nursing Ethics Education and Practice.

    ERIC Educational Resources Information Center

    Cameron, Miriam E.; And Others

    1993-01-01

    Twenty-five persons with acquired immunodeficiency syndrome (AIDS) described and validated 100 ethical problems that are experienced by people with AIDS from 3 levels of ethical inquiry: descriptive ethics, normative ethics, and metaethics. Findings suggest strategies for improving nursing ethics education. (JOW)

  14. The Nematode Caenorhabditis Elegans.

    ERIC Educational Resources Information Center

    Kenyon, Cynthia

    1988-01-01

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

  15. Nematode nervous systems.

    PubMed

    Schafer, William

    2016-10-24

    Nematodes comprise one of the largest phyla in the animal kingdom, both in terms of individual numbers and species diversity. Although only 20,000-30,000 species have been described, it is estimated that the true number ranges between 100,000 and 10 million. Marine, freshwater, and terrestrial species are all widespread, and some nematodes have even been isolated from such inhospitable environments as deserts, hot springs, and polar seas. Some nematode species are parasitic, with either plant or animal hosts; other species are free-living microbivores, scavengers, or predators of insects or other nematodes. Nematodes vary widely in size, from small microbivores that grow no larger than 100 μm to large animal parasites growing to several meters in length. They adopt a variety of reproductive strategies: most species are gonochoristic (i.e., have male and female sexes), but self-fertile hermaphroditic species are not uncommon, and parthenogenetic species are also known. Nematodes belong to the superphylum Ecdysozoa, a clade of moulting animals that also includes arthropods, tardigrades and priapulids. Although nematode fossils are rare, the origin of the nematode phylum is believed to be very ancient, with the divergence from arthropods estimated based on molecular data to have been between 900 and 1,300 Ma.

  16. The Nematode Caenorhabditis Elegans.

    ERIC Educational Resources Information Center

    Kenyon, Cynthia

    1988-01-01

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

  17. Nematode-Trapping Fungi.

    PubMed

    Jiang, Xiangzhi; Xiang, Meichun; Liu, Xingzhong

    2017-01-01

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

  18. Anthelmintics for the control of nematode infections in the brushtail possum (Trichosurus vulpecula).

    PubMed

    Ralston, M J; Stankiewicz, M; Heath, D D

    2001-04-01

    To determine the efficacy of eprinomectin, doramectin and a combination of albendazole and levamisole in suppressing or eliminating nematode infections or faecal egg counts (FEC) in possums naturally or experimentally infected with Parastrongyloides trichosuri, Paraustrostrongylus trichosuri and Trichostrongylus colubriformis. To establish an effective dose of eprinomectin, groups of naturally infected possums were treated with 0, 0.5, 2.5, 5.0 or 7.5 mg/kg liveweight (LW) eprinomectin pour-on (n=6 possums/group) and changes in FEC and nematode worm counts at necropsy determined, 18 days later. Efficacy of the 7.5 mg/kg dose was re-examined in a second group of naturally infected possums (n=12) by monitoring FEC weekly for 28 days post-treatment. Persistence of the anthelmintic effect of doramectin injection was tested using nematode-free possums treated with 0, 0.2, 0.4, 0.6 or 0.8 mg/kg LW (n=3 possums/ group), which were experimentally infected 14 days later with T. colubriformis, Paraustrostrongylus trichosuri and Parastrongyloides trichosuri infective larvae. Response to treatment was assessed by FEC and nematode worm counts at necropsy, 42 days posttreatment. Efficacy of a 1.0 mg/kg dose of doramectin was subsequently examined using naturally infected possums (n=11) by monitoring FEC weekly for 28 days post-treatment. To determine the efficacy of a levamisole-albendazole combination drench, possums with naturally acquired nematode infections (n=6) were treated orally with 37.5 mg/kg LW levamisole plus 23.75 mg/kg LW albendazole on 2 occasions, 7 days apart, and response to treatment was assessed by monitoring FEC for 57 days. Eprinomectin 7.5 mg/kg LW reduced Paraustrostrongylus trichosuri worm counts by 98 % (p<0.05). Doramectin 0.6 mg/kg LW reduced Parastrongyloides trichosuri and Trichostrongylus spp worm counts by 99% (p<0.05) and 0.8 mg/kg LW reduced Paraustrostrongylus trichosuri by 100% (p<0.05), in possums challenged with larvae 14 days after

  19. Efficacy of chlorfenapyr (AC 303630) experimental pour-on and CyLence formulations against naturally acquired louse infestations on cattle in New York.

    PubMed

    Kaufman, P E; Rutz, D A; Doscher, M E; Albright, R

    2001-05-22

    The four chlorfenapyr formulations examined provided 100% control of both the nymphal and adult stages of naturally acquired Bovicola bovis (L.) on cattle up to 35 days after application. Treatment with 6mg chlorfenapyr per kg BW in a 0.12ml per kg BW formulation was as effective as treatment with CyLence (cyfluthrin) in controlling naturally acquired Solenopotes capillatus (Enderlein) on cattle for 35 days. Percent reduction was never greater than 90% with any chlorfenapyr application against Linognathus vituli (L.). However, percent reduction was greater than 90% with CyLence from day 21 through 35. No adverse effects were noted on cattle from any of the chlorfenapyr dosages used.

  20. Recent Duplication and Functional Divergence in Parasitic Nematode Levamisole-Sensitive Acetylcholine Receptors

    PubMed Central

    Duguet, Thomas B.; Charvet, Claude L.; Forrester, Sean G.; Wever, Claudia M.; Dent, Joseph A.; Neveu, Cedric; Beech, Robin N.

    2016-01-01

    Helminth parasites rely on fast-synaptic transmission in their neuromusculature to experience the outside world and respond to it. Acetylcholine plays a pivotal role in this and its receptors are targeted by a wide variety of both natural and synthetic compounds used in human health and for the control of parasitic disease. The model, Caenorhabditis elegans is characterized by a large number of acetylcholine receptor subunit genes, a feature shared across the nematodes. This dynamic family is characterized by both gene duplication and loss between species. The pentameric levamisole-sensitive acetylcholine receptor has been characterized from C. elegans, comprised of five different subunits. More recently, cognate receptors have been reconstituted from multiple parasitic nematodes that are found to vary in subunit composition. In order to understand the implications of receptor composition change and the origins of potentially novel drug targets, we investigated a specific example of subunit duplication based on analysis of genome data for 25 species from the 50 helminth genome initiative. We found multiple independent duplications of the unc-29, acetylcholine receptor subunit, where codon substitution rate analysis identified positive, directional selection acting on amino acid positions associated with subunit assembly. Characterization of four gene copies from a model parasitic nematode, Haemonchus contortus, demonstrated that each copy has acquired unique functional characteristics based on phenotype rescue of transgenic C. elegans and electrophysiology of receptors reconstituted in Xenopus oocytes. We found evidence that a specific incompatibility has evolved for two subunits co-expressed in muscle. We demonstrated that functional divergence of acetylcholine receptors, driven by directional selection, can occur more rapidly than previously thought and may be mediated by alteration of receptor assembly. This phenomenon is common among the clade V parasitic

  1. Influence of infection of cotton by Rotylenchulus Reniformis and Meloidogyne Incognita on the production of enzymes involved in systemic acquired resistance.

    USDA-ARS?s Scientific Manuscript database

    Systemic acquired resistance (SAR), which results in enhanced defense mechanisms in plants, can be elicited by virulent and avirulent strains of pathogens including nematodes. Recent studies of nematode reproduction strongly suggest that Meloidogyne incognita and Rotylenchulus reniformis induce SAR ...

  2. Insights into adaptations to a near-obligate nematode endoparasitic lifestyle from the finished genome of Drechmeria coniospora

    USDA-ARS?s Scientific Manuscript database

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

  3. Acquired fistula of the lacrimal sac and laisser-faire approach. Description of the natural history of acquired fistulas between the lacrimal sac and the skin occurring before planned endonasal dacryocystorhinostomy (DCR) and without any treatment of the fistula.

    PubMed

    Pison, A; Fau, J-L; Racy, E; Fayet, B

    2016-10-01

    The formation of a fistula between the lacrimal sac and the skin is a classic outcome of resistant lacrimal sac abscesses. There is currently no consensus about treatment in such cases. The goal of this study was to describe the natural history of acquired fistulas between the lacrimal sac and the skin, occurring before planned endonasal dacryocystorhinostomy (DCR) and without any treatment of the fistula. This prospective study was only descriptive and included patients between 1999 and 2012. The patients included were adults with a nasolacrimal duct (NLD) obstruction that was planned to be treated with endonasal DCR. A resistant lacrimal sac abscess appeared a few days before the planned surgery, and fistulized spontaneously despite medical treatment. The surgery was not delayed. The DCR was endoscopic. Nothing was done for the fistula. Its healing was spontaneous. The exclusion criteria were the following: congenital fistulas, post-traumatic and/or iatrogenic fistulas, fistulas which had regressed by the day of the surgery, postoperative follow-up less than 5 months, post-traumatic and/or iatrogenic fistulas, any history of previous DCR or any other lacrimal surgery, children. Twenty adults (25 cases) were included in the analysis. Mean age was 79 years old (from 41 to 90). The mean follow-up was 41 months (from 5 to 108 months). The fistula spontaneously disappeared in all cases, less than one month after it had appeared and in a permanent fashion. No unsightly scar developed. Spontaneously acquired fistulas between the lacrimal sac and the skin may occur in the natural course of abscessed acute dacryocystitis. Our study showed spontaneous healing of the fistula post-endoscopic DCR. Fistula excision in fistulous acute dacryocystitis does not seem essential to its healing. The laisser-faire approach appears adequate for aesthetic outcomes as well as for functional outcomes of DCR. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  4. Entomopathogenic nematode application technology

    USDA-ARS?s Scientific Manuscript database

    Biocontrol success when using entomopathogenic nematodes (EPNs) in the genera Heterorhabditis and Steinernema relies on a variety of factors including components of the application event itself. Successful application encompasses both abiotic and biotic influences. For example, adverse array of equi...

  5. Associative change in the representations acquired during conditional discriminations: further analysis of the nature of conditional learning.

    PubMed

    Allman, Melissa J; Ward-Robinson, Jasper; Honey, R C

    2004-04-01

    Three experiments with rats investigated how the associative strengths of the representations that underlie conditional learning change when they are conditioned in compound. The results of each experiment suggest that the representation whose associative strength is most discrepant from the asymptote supported by the outcome of the trial undergoes the greatest change in associative strength. These results parallel those from simple Pavlovian conditioning (e.g., R. A. Rescorla, 2000). are inconsistent with unique-cue and configural accounts of conditional learning, and support a connectionist analysis of learning in which a "winner-takes-all" rule applies to the hidden units that can be activated and acquire associative strength at a given point in time.

  6. Formulation of Nematodes.

    PubMed

    Peters, Arne

    2016-01-01

    The enduring stages of entomopathogenic nematodes of the genera Steinernema and Heterorhabditis are infective juveniles, which require a high humidity and sufficient ventilation for survival. Formulations must account for these requirements. Nematodes may be formulated inside the insects in which they reproduced or they need to be cleaned and mixed with a suitable binder to maintain humidity but allowing for gas exchange. Another method for formulation is the encapsulation in beads of Ca-alginate. Generic procedures for these formulation techniques are described.

  7. Neuroparasitic infections: nematodes.

    PubMed

    Walker, M D; Zunt, J R

    2005-09-01

    Globalization has produced an increase in the number of people at risk for contracting parasitic infection. Central nervous system infection by nematodal parasites can be devastating. Early recognition and treatment of infection can significantly decrease morbidity of the parasitic infection, as well as the risk of secondary superinfection. The clinical presentation, diagnosis, and treatment for five of the more common nematodal infections of the nervous system--Angiostrongylus spp., Baylisacaris procyonis, Gnathostoma spinigerum, Strongyloides stercoralis, and Toxocara spp.--is reviewed.

  8. Breeding a super nematode for enhanced insect pest suppression

    USDA-ARS?s Scientific Manuscript database

    Entomopathogenic nematodes in the genera Heterorhabditis and Steinernema are important regulators of natural insect populations, and are used commercially as biological control agents for pest suppression. Successful biocontrol applications depend on the introduced organism having an array of benef...

  9. The nature of self-esteem and its relationship to anxiety and depression in adult acquired brain injury.

    PubMed

    Longworth, Catherine; Deakins, Joseph; Rose, David; Gracey, Fergus

    2016-08-31

    Acquired brain injury (ABI) has a negative impact on self-esteem, which is in turn associated with mood disorders, maladaptive coping and reduced community participation. The aim of the current research was to explore self-esteem as a multi-dimensional construct and identify which factors are associated with symptoms of anxiety or depression. Eighty adults with ABI aged 17-56 years completed the Robson Self-Esteem Scale (RSES), of whom 65 also completed the Hospital Anxiety and Depression Scale; 57.5% of the sample had clinically low self-esteem. The RSES had good internal consistency (α =   .89), and factor analysis identified four factors, which differed from those found previously in other populations. Multiple regression analysis revealed anxiety was differentially predicted by "Self-Worth" and "Self-Efficacy", R(2) =   .44, F(4, 58) =   9, p <   .001, and depression by "Self-Regard", R(2) =   .38, F(4, 58) =   9, p <   .001. A fourth factor, "Confidence", did not predict depression or anxiety. In conclusion, the RSES is a reliable measure of self-esteem after ABI. Self-esteem after ABI is multidimensional and differs in structure from self-esteem in the general population. A multidimensional model of self-esteem may be helpful in development of transdiagnostic cognitive behavioural accounts of adjustment.

  10. Transgenic Strategies for Enhancement of Nematode Resistance in Plants

    PubMed Central

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

    2017-01-01

    Plant parasitic nematodes (PPNs) are obligate biotrophic parasites causing serious damage and reduction in crop yields. Several economically important genera parasitize various crop plants. The root-knot, root lesion, and cyst nematodes are the three most economically damaging genera of PPNs on crops within the family Heteroderidae. It is very important to devise various management strategies against PPNs in economically important crop plants. Genetic engineering has proven a promising tool for the development of biotic and abiotic stress tolerance in crop plants. Additionally, the genetic engineering leading to transgenic plants harboring nematode resistance genes has demonstrated its significance in the field of plant nematology. Here, we have discussed the use of genetic engineering for the development of nematode resistance in plants. This review article also provides a detailed account of transgenic strategies for the resistance against PPNs. The strategies include natural resistance genes, cloning of proteinase inhibitor coding genes, anti-nematodal proteins and use of RNA interference to suppress nematode effectors. Furthermore, the manipulation of expression levels of genes induced and suppressed by nematodes has also been suggested as an innovative approach for inducing nematode resistance in plants. The information in this article will provide an array of possibilities to engineer resistance against PPNs in different crop plants. PMID:28536595

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

    PubMed

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

    2017-01-01

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

  12. Seasonal patterns of gastrointestinal nematode infection in goats on two Lithuanian farms.

    PubMed

    Stadalienė, Inga; Höglund, Johan; Petkevičius, Saulius

    2015-03-19

    This study investigated seasonal changes in naturally acquired gastrointestinal nematode (GIN) infections on two Lithuanian goat farms with different parasite control practices. On both farms, nematode faecal egg counts (FEC) and larval cultures were obtained from 15 adult and 10 young goats at bi-weekly intervals from April 2012 to April 2013. Goats on farm A were dewormed with ivermectin (0.3 mg/kg body weight) in October/November 2012, whereas the animals on farm B were left untreated. Thirteen young goats were slaughtered in August/November 2012 and April 2013 and worm burdens in the gastrointestinal tract were enumerated. In goats from both farms, Teladorsagia, Trichostrongylus, Oesophagostomum, Chabertia and Haemonchus were the dominant GIN genera. Herbage contamination with infective third-stage larvae (L3) peaked in July/August and resulted in high FEC in September/October. Parasitological examination at slaughter showed that Teladorsagia spp. and Haemonchus contortus survived the winter, both in the abomasal mucosa as adults and as early fourth-stage larvae (EL4). Deworming on farm A significantly reduced FEC, especially of H. contortus, at the start of the grazing period compared with the untreated farm B (P < 0.05). Goats were heavily infected with several GIN throughout the year. Strategic anthelmintic treatment during housing significantly reduced nematode egg output, in particular by H. contortus, at the start of the grazing season.

  13. Algivore or Phototroph? Plakobranchus ocellatus (Gastropoda) Continuously Acquires Kleptoplasts and Nutrition from Multiple Algal Species in Nature

    PubMed Central

    Maeda, Taro; Hirose, Euichi; Chikaraishi, Yoshito; Kawato, Masaru; Takishita, Kiyotaka; Yoshida, Takao; Verbruggen, Heroen; Tanaka, Jiro; Shimamura, Shigeru; Takaki, Yoshihiro; Tsuchiya, Masashi; Iwai, Kenji; Maruyama, Tadashi

    2012-01-01

    The sea slug Plakobranchus ocellatus (Sacoglossa, Gastropoda) retains photosynthetically active chloroplasts from ingested algae (functional kleptoplasts) in the epithelial cells of its digestive gland for up to 10 months. While its feeding behavior has not been observed in natural habitats, two hypotheses have been proposed: 1) adult P. ocellatus uses kleptoplasts to obtain photosynthates and nutritionally behaves as a photoautotroph without replenishing the kleptoplasts; or 2) it behaves as a mixotroph (photoautotroph and herbivorous consumer) and replenishes kleptoplasts continually or periodically. To address the question of which hypothesis is more likely, we examined the source algae for kleptoplasts and temporal changes in kleptoplast composition and nutritional contribution. By characterizing the temporal diversity of P. ocellatus kleptoplasts using rbcL sequences, we found that P. ocellatus harvests kleptoplasts from at least 8 different siphonous green algal species, that kleptoplasts from more than one species are present in each individual sea slug, and that the kleptoplast composition differs temporally. These results suggest that wild P. ocellatus often feed on multiple species of siphonous algae from which they continually obtain fresh chloroplasts. By estimating the trophic position of wild and starved P. ocellatus using the stable nitrogen isotopic composition of amino acids, we showed that despite the abundance of kleptoplasts, their photosynthates do not contribute greatly to the nutrition of wild P. ocellatus, but that kleptoplast photosynthates form a significant source of nutrition for starved sea slugs. The herbivorous nature of wild P. ocellatus is consistent with insights from molecular analyses indicating that kleptoplasts are frequently replenished from ingested algae, leading to the conclusion that natural populations of P. ocellatus do not rely on photosynthesis but mainly on the digestion of ingested algae. PMID:22848693

  14. Expressed sequence tags of the peanut pod nematode Ditylenchus africanus: the first transcriptome analysis of an Anguinid nematode.

    PubMed

    Haegeman, Annelies; Jacob, Joachim; Vanholme, Bartel; Kyndt, Tina; Mitreva, Makedonka; Gheysen, Godelieve

    2009-09-01

    In this study, 4847 expressed sequenced tags (ESTs) from mixed stages of the migratory plant-parasitic nematode Ditylenchus africanus (peanut pod nematode) were investigated. It is the first molecular survey of a nematode which belongs to the family of the Anguinidae (order Rhabditida, superfamily Sphaerularioidea). The sequences were clustered into 2596 unigenes, of which 43% did not show any homology to known protein, nucleotide, nematode EST or plant-parasitic nematode genome sequences. Gene ontology mapping revealed that most putative proteins are involved in developmental and reproductive processes. In addition unigenes involved in oxidative stress as well as in anhydrobiosis, such as LEA (late embryogenesis abundant protein) and trehalose-6-phosphate synthase were identified. Other tags showed homology to genes previously described as being involved in parasitism (expansin, SEC-2, calreticulin, 14-3-3b and various allergen proteins). In situ hybridization revealed that the expression of a putative expansin and a venom allergen protein was restricted to the gland cell area of the nematode, being in agreement with their presumed role in parasitism. Furthermore, seven putative novel candidate parasitism genes were identified based on the prediction of a signal peptide in the corresponding protein sequence and homologous ESTs exclusively in parasitic nematodes. These genes are interesting for further research and functional characterization. Finally, 34 unigenes were retained as good target candidates for future RNAi experiments, because of their nematode specific nature and observed lethal phenotypes of Caenorhabditis elegans homologs.

  15. Expressed sequence tags of the peanut pod nematode Ditylenchus africanus: the first transcriptome analysis of an Anguinid nematode

    PubMed Central

    Haegeman, Annelies; Jacob, Joachim; Vanholme, Bartel; Kyndt, Tina; Mitreva, Makedonka; Gheysen, Godelieve

    2009-01-01

    In this study, 4847 expressed sequenced tags (ESTs) from mixed stages of the migratory plant-parasitic nematode Ditylenchus africanus (peanut pod nematode) were investigated. It is the first molecular survey of a nematode which belongs to the family of the Anguinidae (order Rhabditida, superfamily Sphaerularioidea). The sequences were clustered into 2596 unigenes, of which 43% did not show any homology to known protein, nucleotide, nematode EST or plant-parasitic nematode genome sequences. Gene ontology mapping revealed that most putative proteins are involved in developmental and reproductive processes. In addition unigenes involved in oxidative stress as well as in anhydrobiosis, such as LEA (late embryogenesis abundant protein) and trehalose-6-phosphate synthase were identified. Other tags showed homology to genes previously described as being involved in parasitism (expansin, SEC-2, calreticulin, 14-3-3b and various allergen proteins). In situ hybridization revealed that the expression of a putative expansin and a venom allergen protein was restricted to the gland cell area of the nematode, being in agreement with their presumed role in parasitism. Furthermore, 7 putative novel candidate parasitism genes were identified based on the prediction of a signal peptide in the corresponding protein sequence and homologous ESTs exclusively in parasitic nematodes. These genes are interesting for further research and functional characterization. Finally, 34 unigenes were retained as good target candidates for future RNAi experiments, because of their nematode specific nature and observed lethal phenotypes of Caenorhabditis elegans homologs. PMID:19383517

  16. A Unique Subset of γδ T Cells Expands and Produces IL-10 in Patients with Naturally Acquired Immunity against Falciparum Malaria.

    PubMed

    Taniguchi, Tomoyo; Md Mannoor, Kaiissar; Nonaka, Daisuke; Toma, Hiromu; Li, Changchun; Narita, Miwako; Vanisaveth, Viengxay; Kano, Shigeyuki; Takahashi, Masuhiro; Watanabe, Hisami

    2017-01-01

    Although expansions in γδ T cell populations are known to occur in the peripheral blood of patients infected with Plasmodium falciparum, the role of these cells in people with naturally acquired immunity against P. falciparum who live in malaria-endemic areas is poorly understood. We used a cross-sectional survey to investigate the role of peripheral blood γδ T cells in people living in Lao People's Democratic Republic, a malaria-endemic area. We found that the proportion of non-Vγ9 γδ T cells was higher in non-hospitalized uncomplicated falciparum malaria patients (UMPs) from this region. Notably, we found that the non-Vγ9 γδ T cells in the peripheral blood of UMPs and negative controls from this region had the potential to expand and produce IL-10 and interferon-γ when cultured in the presence of IL-2 and/or crude P. falciparum antigens for 10 days. Furthermore, these cells were associated with plasma interleukin 10 (IL-10), which was elevated in UMPs. This is the first report demonstrating that, in UMPs living in a malaria-endemic area, a γδ T cell subset, the non-Vγ9 γδT cells, expands and produces IL-10. These results contribute to understanding of the mechanisms of naturally acquired immunity against P. falciparum.

  17. A Unique Subset of γδ T Cells Expands and Produces IL-10 in Patients with Naturally Acquired Immunity against Falciparum Malaria

    PubMed Central

    Taniguchi, Tomoyo; Md Mannoor, Kaiissar; Nonaka, Daisuke; Toma, Hiromu; Li, Changchun; Narita, Miwako; Vanisaveth, Viengxay; Kano, Shigeyuki; Takahashi, Masuhiro; Watanabe, Hisami

    2017-01-01

    Although expansions in γδ T cell populations are known to occur in the peripheral blood of patients infected with Plasmodium falciparum, the role of these cells in people with naturally acquired immunity against P. falciparum who live in malaria-endemic areas is poorly understood. We used a cross-sectional survey to investigate the role of peripheral blood γδ T cells in people living in Lao People’s Democratic Republic, a malaria-endemic area. We found that the proportion of non-Vγ9 γδ T cells was higher in non-hospitalized uncomplicated falciparum malaria patients (UMPs) from this region. Notably, we found that the non-Vγ9 γδ T cells in the peripheral blood of UMPs and negative controls from this region had the potential to expand and produce IL-10 and interferon-γ when cultured in the presence of IL-2 and/or crude P. falciparum antigens for 10 days. Furthermore, these cells were associated with plasma interleukin 10 (IL-10), which was elevated in UMPs. This is the first report demonstrating that, in UMPs living in a malaria-endemic area, a γδ T cell subset, the non-Vγ9 γδT cells, expands and produces IL-10. These results contribute to understanding of the mechanisms of naturally acquired immunity against P. falciparum. PMID:28769886

  18. Roles of Steroids in Nematodes

    USDA-ARS?s Scientific Manuscript database

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

  19. Nematode-borne plant viruses

    USDA-ARS?s Scientific Manuscript database

    There are 30 plant-parasitic nematode species that are known to transmit 14 plant viruses. Nematode-transmitted viruses affect a range of agriculturally important crops including grape, cherry, potato, and tomato. The nematodes that transmit viruses are found in two families, Longidoridae and Tric...

  20. Nematode cholinergic pharmacology

    SciTech Connect

    Segerberg, M.A.

    1989-01-01

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

  1. Comparative genomics of nematodes.

    PubMed

    Mitreva, Makedonka; Blaxter, Mark L; Bird, David M; McCarter, James P

    2005-10-01

    Recent transcriptome and genome projects have dramatically expanded the biological data available across the phylum Nematoda. Here we summarize analyses of these sequences, which have revealed multiple unexpected results. Despite a uniform body plan, nematodes are more diverse at the molecular level than was previously recognized, with many species- and group-specific novel genes. In the genus Caenorhabditis, changes in chromosome arrangement, particularly local inversions, are also rapid, with breakpoints occurring at 50-fold the rate in vertebrates. Tylenchid plant parasitic nematode genomes contain several genes closely related to genes in bacteria, implicating horizontal gene transfer events in the origins of plant parasitism. Functional genomics techniques are also moving from Caenorhabditis elegans to application throughout the phylum. Soon, eight more draft nematode genome sequences will be available. This unique resource will underpin both molecular understanding of these most abundant metazoan organisms and aid in the examination of the dynamics of genome evolution in animals.

  2. Cellular proliferation rate and insulin-like growth factor binding protein (IGFBP)-2 and IGFBP-3 and estradiol receptor alpha expression in the mammary gland of dairy heifers naturally infected with gastrointestinal nematodes during development.

    PubMed

    Perri, A F; Dallard, B E; Baravalle, C; Licoff, N; Formía, N; Ortega, H H; Becú-Villalobos, D; Mejia, M E; Lacau-Mengido, I M

    2014-01-01

    Mammary ductal morphogenesis during prepuberty occurs mainly in response to insulin-like growth factor-1 (IGF-1) and estradiol stimulation. Dairy heifers infected with gastrointestinal nematodes have reduced IGF-1 levels, accompanied by reduced growth rate, delayed puberty onset, and lower parenchyma-stroma relationship in their mammary glands. Immunohistochemical studies were undertaken to determine variations in cell division rate, IGF-1 system components, and estradiol receptors (ESR) during peripubertal development in the mammary glands of antiparasitic-treated and untreated Holstein heifers naturally infected with gastrointestinal nematodes. Mammary biopsies were taken at 20, 30, 40, and 70 wk of age. Proliferating cell nuclear antigen immunolabeling, evident in nuclei, tended to be higher in the parenchyma of the glands from treated heifers than in those from untreated. Insulin-like growth factor binding proteins (IGFBP) type 2 and type 3 immunolabeling was cytoplasmic and was evident in stroma and parenchyma. The IGFBP2-labeled area was lower in treated than in untreated heifers. In the treated group, a maximal expression of this protein was seen at 40 wk of age, whereas in the untreated group the labeling remained constant. No differences were observed for IGFBP3 between treatment groups or during development. Immunolabeling for α ESR (ESR1) was evident in parenchymal nuclei and was higher in treated than in untreated heifers. In the treated group, ESR1 peaked at 30 wk of age and then decreased. These results demonstrate that the parasite burden in young heifers negatively influence mammary gland development, affecting cell division rate and parameters related to estradiol and IGF-1 signaling in the gland.

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

    PubMed

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

    2016-03-21

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

  4. Ophthalmologic and oculopathologic findings in red-tailed hawks and Cooper's hawks with naturally acquired West Nile virus infection.

    PubMed

    Pauli, Amy M; Cruz-Martinez, Luis A; Ponder, Julia B; Redig, Patrick T; Glaser, Amy L; Klauss, Gia; Schoster, James V; Wünschmann, Arno

    2007-10-15

    To assess ophthalmologic features and ocular lesions in red-tailed hawks and Cooper's hawks naturally infected with West Nile virus (WNV). Original study. 13 hawks. All hawks underwent complete ophthalmic examinations including slit lamp biomicroscopy and binocular indirect ophthalmoscopy. Eleven hawks were euthanized because of a grave prognosis; complete necropsies were performed. Eyes, brain, heart, and kidneys were processed for histologic and immunohistochemical examinations. Pooled tissue homogenates and aqueous humor samples were assessed for WNV nucleic acid via PCR assay, and anti-WNV antibody titers in aqueous humor and plasma were determined. All birds had similar funduscopic abnormalities including exudative chorioretinal lesions and chorioretinal scarring in a geographic or linear pattern. Eleven birds were euthanized, and 2 birds were released. Plasma from both released hawks and plasma and aqueous humor of all euthanized hawks that were evaluated contained anti-WNV antibodies. Except for 1 hawk, all euthanized hawks had WNV-associated disease (determined via detection of WNV antigen or nucleic acid in at least 1 organ). Histopathologic ocular abnormalities, most commonly pectenitis, were detected in all euthanized birds; several birds had segmental choroiditis, often with corresponding segmental retinal atrophy. West Nile virus antigen was detected in the retinas of 9 of the euthanized birds. In 2 hawks, WNV antigen was detected in the retina only. Results indicated that funduscopically detectable chorioretinal lesions appear to be associated with WNV disease in hawks. Detection of ocular lesions may aid in antemortem or postmortem diagnosis of this condition.

  5. Lateralized scale-eating behaviour of cichlid is acquired by learning to use the naturally stronger side.

    PubMed

    Takeuchi, Yuichi; Oda, Yoichi

    2017-08-21

    The scale-eating cichlid Perissodus microlepis exhibits significant lateralised predation behaviour using an asymmetric mouth. But how the acquisition of the behavioural laterality depends, if at all, on experience during development remains obscure. Here, naïve juveniles were tested in a series of predation sessions. Initially, they attacked both sides of the prey, but during subsequent sessions, attack direction gradually lateralised to the skewed mouth (dominant) side. Attack side preference of juveniles that had accumulated scale-eating experience during successive sessions was significantly higher than that of naïve juveniles at the same age and naïve adults. Thus, the lateralised behaviour was a learned experience, and did not develop with age. Surprisingly, however, both maximum amplitude and angular velocity of body flexion during attack of naïve fish was dominant on one side. Therefore, scale-eating fish have a naturally stronger side for attacking prey fish, and they learn to use the dominant side through experience.

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

    PubMed

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

    1989-06-01

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

  7. Heme acquisition in the parasitic filarial nematode Brugia malayi

    PubMed Central

    Luck, Ashley N.; Yuan, Xiaojing; Voronin, Denis; Slatko, Barton E.; Hamza, Iqbal; Foster, Jeremy M.

    2016-01-01

    Nematodes lack a heme biosynthetic pathway and must acquire heme from exogenous sources. Given the indispensable role of heme, this auxotrophy may be exploited to develop drugs that interfere with heme uptake in parasites. Although multiple heme-responsive genes (HRGs) have been characterized within the free-living nematode Caenorhabditis elegans, we have undertaken the first study of heme transport in Brugia malayi, a causative agent of lymphatic filariasis. Through functional assays in yeast, as well as heme analog, RNAi, and transcriptomic experiments, we have shown that the heme transporter B. malayi HRG-1 (BmHRG-1) is indeed functional in B. malayi. In addition, BmHRG-1 localizes both to the endocytic compartments and cell membrane when expressed in yeast cells. Transcriptomic sequencing revealed that BmHRG-1, BmHRG-2, and BmMRP-5 (all orthologs of HRGs in C. elegans) are down-regulated in heme-treated B. malayi, as compared to non–heme-treated control worms. Likely because of short gene lengths, multiple exons, other HRGs in B. malayi (BmHRG-3–6) remain unidentified. Although the precise mechanisms of heme homeostasis in a nematode with the ability to acquire heme remains unknown, this study clearly demonstrates that the filarial nematode B. malayi is capable of transporting exogenous heme.—Luck, A. N., Yuan, X., Voronin, D., Slatko, B. E., Hamza, I., Foster, J. M. Heme acquisition in the parasitic filarial nematode Brugia malayi. PMID:27363426

  8. A comparative study of the effects of four treatment regimes on ivermectin efficacy, body weight and pasture contamination in lambs naturally infected with gastrointestinal nematodes in Scotland

    PubMed Central

    Kenyon, Fiona; McBean, David; Greer, Andrew W.; Burgess, Charlotte G.S.; Morrison, Alison A.; Bartley, David J.; Bartley, Yvonne; Devin, Leigh; Nath, Mintu; Jackson, Frank

    2013-01-01

    Refugia-based drenching regimes have been widely recommended to slow development of anthelmintic resistance but there are few comparisons between different treatment approaches in the UK. The impact of four ivermectin treatment regimes on drug efficacy, lamb body weight and nematode contamination during a 154 day grazing season were evaluated in a consecutive five year field study. Regimes were whole-flock treatment every 4 weeks (NST), targeted selective treatment (TST) based on individual performance, strategic whole-flock treatments at pre-determined times (SPT) or whole-flock treatment when clinical signs were apparent (MT). Mean numbers of ivermectin drenches administered per season were 4.0, 1.8, 2.0 and 1.4 for NST, TST, SPT and MT groups, respectively. The mean anthelmintic efficacy (AE) for each treatment group was based on faecal egg count reduction post-treatment employing a bootstrap sampling based algorithm. Mean AE was 95–98% for all groups in 2006 and mean AE (95% confidence limits) for NST declined to 62% (55%, 68%) in 2010. In comparison, AE for TST, SPT and MT in 2010 were 86% (81%, 92%), 86% (83%, 90%) and 83% (78%, 88%), respectively. Body weight in TST and SPT was similar to NST in all years (p > 0.05), however MT lambs were lighter than NST in 2006–2008 (p ⩽ 0.04). Tracer lamb worm burdens was lowest in NST but was not significantly different between other groups. Overall, both the TST and SPT regimes appeared to maintain animal performance and conserve anthelmintic efficacy compared with a neo-suppressive anthelmintic treatment regime. PMID:24533296

  9. How nematode sperm crawl.

    PubMed

    Bottino, Dean; Mogilner, Alexander; Roberts, Tom; Stewart, Murray; Oster, George

    2002-01-15

    Sperm of the nematode, Ascaris suum, crawl using lamellipodial protrusion, adhesion and retraction, a process analogous to the amoeboid motility of other eukaryotic cells. However, rather than employing an actin cytoskeleton to generate locomotion, nematode sperm use the major sperm protein (MSP). Moreover, nematode sperm lack detectable molecular motors or the battery of actin-binding proteins that characterize actin-based motility. The Ascaris system provides a simple 'stripped down' version of a crawling cell in which to examine the basic mechanism of cell locomotion independently of other cellular functions that involve the cytoskeleton. Here we present a mechanochemical analysis of crawling in Ascaris sperm. We construct a finite element model wherein (a) localized filament polymerization and bundling generate the force for lamellipodial extension and (b) energy stored in the gel formed from the filament bundles at the leading edge is subsequently used to produce the contraction that pulls the rear of the cell forward. The model reproduces the major features of crawling sperm and provides a framework in which amoeboid cell motility can be analyzed. Although the model refers primarily to the locomotion of nematode sperm, it has important implications for the mechanics of actin-based cell motility.

  10. Nematode management in pecans

    USDA-ARS?s Scientific Manuscript database

    In 2002, the pecan root-knot nematode (Meloidogyne partityla = PRKN) was found on pecan in the southeastern U.S. and was associated with stressed trees exhibiting dead branches in the upper canopy and (or) typical mouse ear (ME) associated foliar symptoms. This research evaluates the host susceptib...

  11. Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs48/45 and Pfs230 in an Area of Seasonal Transmission ▿

    PubMed Central

    Ouédraogo, André Lin; Roeffen, Will; Luty, Adrian J. F.; de Vlas, Sake J.; Nebie, Issa; Ilboudo-Sanogo, Edith; Cuzin-Ouattara, Nadine; Teleen, Karina; Tiono, Alfred B.; Sirima, Sodiomon Bienvenu; Verhave, Jan-Peter; Bousema, Teun; Sauerwein, Robert

    2011-01-01

    Acquisition of immunity to Plasmodium falciparum sexual stages is a key determinant for reducing human-mosquito transmission by preventing the fertilization and the development of the parasite in the mosquito midgut. Naturally acquired immunity against sexual stages may therefore form the basis for the development of transmission-blocking vaccines, but studies conducted to date offer little in the way of consistent findings. Here, we describe the acquisition of antigametocyte immune responses in malaria-exposed individuals in Burkina Faso. A total of 719 blood samples were collected in a series of three cross-sectional surveys at the start, peak, and end of the wet season. The seroprevalence of antibodies with specificity for the sexual stage antigens Pfs48/45 and Pfs230 was 2-fold lower (22 to 28%) than that for an asexual blood stage antigen glutamate-rich protein (GLURP) (65%) or for the preerythrocytic stage antigen circumsporozoite protein (CSP) (54%). The youngest children responded at frequencies similar to those for all four antigens but, in contrast with the immune responses to GLURP and CSP that increased with age independently of season and area of residence, there was no evidence for a clear age dependence of responses to Pfs48/45 and Pfs230. Anti-Pfs230 antibodies were most prevalent at the peak of the wet season (P < 0.001). Our findings suggest that naturally acquired immunity against Pfs48/45 and Pfs230 is a function of recent exposure rather than of cumulative exposure to gametocytes. PMID:21969000

  12. Naturally Acquired Antibodies Specific for Plasmodium falciparum Reticulocyte-Binding Protein Homologue 5 Inhibit Parasite Growth and Predict Protection From Malaria

    PubMed Central

    Tran, Tuan M.; Ongoiba, Aissata; Coursen, Jill; Crosnier, Cecile; Diouf, Ababacar; Huang, Chiung-Yu; Li, Shanping; Doumbo, Safiatou; Doumtabe, Didier; Kone, Younoussou; Bathily, Aboudramane; Dia, Seydou; Niangaly, Moussa; Dara, Charles; Sangala, Jules; Miller, Louis H.; Doumbo, Ogobara K.; Kayentao, Kassoum; Long, Carole A.; Miura, Kazutoyo; Wright, Gavin J.; Traore, Boubacar; Crompton, Peter D.

    2014-01-01

    Background. Plasmodium falciparum reticulocyte-binding protein homologue 5 (PfRH5) is a blood-stage parasite protein essential for host erythrocyte invasion. PfRH5-specific antibodies raised in animals inhibit parasite growth in vitro, but the relevance of naturally acquired PfRH5-specific antibodies in humans is unclear. Methods. We assessed pre–malaria season PfRH5-specific immunoglobulin G (IgG) levels in 357 Malian children and adults who were uninfected with Plasmodium. Subsequent P. falciparum infections were detected by polymerase chain reaction every 2 weeks and malaria episodes by weekly physical examination and self-referral for 7 months. The primary outcome was time between the first P. falciparum infection and the first febrile malaria episode. PfRH5-specific IgG was assayed for parasite growth-inhibitory activity. Results. The presence of PfRH5-specific IgG at enrollment was associated with a longer time between the first blood-stage infection and the first malaria episode (PfRH5-seropositive median: 71 days, PfRH5-seronegative median: 18 days; P = .001). This association remained significant after adjustment for age and other factors associated with malaria risk/exposure (hazard ratio, .62; P = .02). Concentrated PfRH5-specific IgG purified from Malians inhibited P. falciparum growth in vitro. Conclusions. Naturally acquired PfRH5-specific IgG inhibits parasite growth in vitro and predicts protection from malaria. These findings strongly support efforts to develop PfRH5 as an urgently needed blood-stage malaria vaccine. Clinical Trials Registration NCT01322581. PMID:24133188

  13. Antibody Responses and Avidity of Naturally Acquired Anti-Plasmodium vivax Duffy Binding Protein (PvDBP) Antibodies in Individuals from an Area with Unstable Malaria Transmission

    PubMed Central

    Zakeri, Sedigheh; Babaeekhou, Laleh; Mehrizi, Akram Abouie; Abbasi, Maryam; Djadid, Navid Dinparast

    2011-01-01

    Plasmodium vivax remains an important cause of morbidity outside Africa, and no effective vaccine is available against this parasite. The P. vivax Duffy binding protein (PvDBP) is essential during merozoite invasion into erythrocytes, and it is a target for protective immunity against malaria. This investigation was designed to evaluate naturally acquired antibodies to two variant forms of PvDBP-II antigen (DBP-I and -VI) in malaria individuals (N = 85; median = 22 years) who were living in hypoendemic areas in Iran. The two PvDBP-II variants were expressed in Escherichia coli, and immunoglobulin G (IgG) isotype composition and avidity of naturally acquired antibodies to these antigens were measured using enzyme-linked immunosorbent assay (ELISA). Results showed that almost 32% of the studied individuals had positive antibody responses to the two PvDBP-II variants, and the prevalence of responders did not differ significantly (P > 0.05; χ2 test). The IgG-positive samples exhibited 37.03% and 40.8% high-avidity antibodies for PvDBP-I and PvDBP-VI variants, respectively. Furthermore, high-avidity IgG1 antibody was found in 39.1% of positive sera for each examined variant antigen. The avidity of antibodies for both PvDBP variant antigens and the prevalence of responders with high- and intermediate-avidity IgG, IgG1, and IgG3 antibodies were similar in patients (P > 0.05; χ2 test). Moreover, the prevalence of IgG antibody responses to the two variants significantly increased with exposure and host age. To sum up, the results provided additional data in our understanding of blood-stage immunity to PvDBP, supporting the rational development of an effective blood-stage vaccine based on this antigen. PMID:21633032

  14. Reciprocal Interactions between Nematodes and Their Microbial Environments

    PubMed Central

    Midha, Ankur; Schlosser, Josephine; Hartmann, Susanne

    2017-01-01

    Parasitic nematode infections are widespread in nature, affecting humans as well as wild, companion, and livestock animals. Most parasitic nematodes inhabit the intestines of their hosts living in close contact with the intestinal microbiota. Many species also have tissue migratory life stages in the absence of severe systemic inflammation of the host. Despite the close coexistence of helminths with numerous microbes, little is known concerning these interactions. While the environmental niche is considerably different, the free-living nematode Caenorhabditis elegans (C. elegans) is also found amongst a diverse microbiota, albeit on decaying organic matter. As a very well characterized model organism that has been intensively studied for several decades, C. elegans interactions with bacteria are much more deeply understood than those of their parasitic counterparts. The enormous breadth of understanding achieved by the C. elegans research community continues to inform many aspects of nematode parasitology. Here, we summarize what is known regarding parasitic nematode-bacterial interactions while comparing and contrasting this with information from work in C. elegans. This review highlights findings concerning responses to bacterial stimuli, antimicrobial peptides, and the reciprocal influences between nematodes and their environmental bacteria. Furthermore, the microbiota of nematodes as well as alterations in the intestinal microbiota of mammalian hosts by helminth infections are discussed. PMID:28497029

  15. Acquired Immunity to Malaria

    PubMed Central

    Doolan, Denise L.; Dobaño, Carlota; Baird, J. Kevin

    2009-01-01

    Naturally acquired immunity to falciparum malaria protects millions of people routinely exposed to Plasmodium falciparum infection from severe disease and death. There is no clear concept about how this protection works. There is no general agreement about the rate of onset of acquired immunity or what constitutes the key determinants of protection; much less is there a consensus regarding the mechanism(s) of protection. This review summarizes what is understood about naturally acquired and experimentally induced immunity against malaria with the help of evolving insights provided by biotechnology and places these insights in the context of historical, clinical, and epidemiological observations. We advocate that naturally acquired immunity should be appreciated as being virtually 100% effective against severe disease and death among heavily exposed adults. Even the immunity that occurs in exposed infants may exceed 90% effectiveness. The induction of an adult-like immune status among high-risk infants in sub-Saharan Africa would greatly diminish disease and death caused by P. falciparum. The mechanism of naturally acquired immunity that occurs among adults living in areas of hyper- to holoendemicity should be understood with a view toward duplicating such protection in infants and young children in areas of endemicity. PMID:19136431

  16. Acquired hyperpigmentations*

    PubMed Central

    Cestari, Tania Ferreira; Dantas, Lia Pinheiro; Boza, Juliana Catucci

    2014-01-01

    Cutaneous hyperpigmentations are frequent complaints, motivating around 8.5% of all dermatological consultations in our country. They can be congenital, with different patterns of inheritance, or acquired in consequence of skin problems, systemic diseases or secondary to environmental factors. The vast majority of them are linked to alterations on the pigment melanin, induced by different mechanisms. This review will focus on the major acquired hyperpigmentations associated with increased melanin, reviewing their mechanisms of action and possible preventive measures. Particularly prominent aspects of diagnosis and therapy will be emphasized, with focus on melasma, post-inflammatory hyperpigmentation, periorbital pigmentation, dermatosis papulosa nigra, phytophotodermatoses, flagellate dermatosis, erythema dyschromicum perstans, cervical poikiloderma (Poikiloderma of Civatte), acanthosis nigricans, cutaneous amyloidosis and reticulated confluent dermatitis PMID:24626644

  17. [Trophic types of the nematodes].

    PubMed

    Kornobis, Franciszek Wojciech

    2008-01-01

    The aim of the article is to present trophic types (i.e non-systematic groups feeding on the same kind of food) of the nematodes. Seven trophic types (covering all known species) are described: (1) microbivores (nematodes feeding on unicellular microorganisms) with two examples: C. elegans and the nematodes of two families: Steinernematidae and Heterorhabditidae, (2) parasites of Vertebrates, (3) parasites of Invertebrates with example of the family Acugutturidae, (4) parasites of plants with two examples: Tylenchorhynchus dubius and Heterodera schachtii, (5) parasites of fungi, (6) predatory nematodes, (7) omnivores (nematodes feeding on different kinds of food). Basic information on the anatomy of the alimentary canal and feeding behaviour of the nematodes are also provided.

  18. Soil Nematodes in Terrestrial Ecosystems

    PubMed Central

    Yeates, G. W.

    1979-01-01

    There has been much work on plant-feeding nematodes, and less on other soil nematodes, their distribution, abundance, intrinsic properties, and interactions with biotic and abiotic factors. Seasonal variation in nematode fauna as a whole is correlated with factors such as moisture, temperature, and plant growth; at each site nematode distribution generally reflects root distribution. There is a positive correlation between average nematode abundance and primary production as controlled by moisture, temperature, nutrients, etc. Soil nematodes, whether bacterial feeders, fungivores, plant feeders, omnivores, or predators, all influence the populations of the organisms they feed on. Although soil trematodes probably contribute less than 1% to soil respiration they may play an important role in nutrient cycling in the soil through their influence on bacterial growth and plant nutrient availability. PMID:19300638

  19. RNAi from plants to nematodes.

    PubMed

    Gheysen, Godelieve; Vanholme, Bartel

    2007-03-01

    Coincident with the award of the Nobel Prize for Medicine in 2006 to Fire and Mello for their discovery of RNAi, plant scientists have succeeded in using RNAi-based techniques to control nematodes, a hitherto unmanageable plant parasite. Recent work has demonstrated that the expression in a host plant of double-stranded RNA targeting housekeeping or parasitism genes in the root-knot nematode resulted in resistance to nematode infection.

  20. Toward 959 nematode genomes

    PubMed Central

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

    2012-01-01

    The sequencing of the complete genome of the nematode Caenorhabditis elegans was a landmark achievement and ushered in a new era of whole-organism, systems analyses of the biology of this powerful model organism. The success of the C. elegans genome sequencing project also inspired communities working on other organisms to approach genome sequencing of their species. The phylum Nematoda is rich and diverse and of interest to a wide range of research fields from basic biology through ecology and parasitic disease. For all these communities, it is now clear that access to genome scale data will be key to advancing understanding, and in the case of parasites, developing new ways to control or cure diseases. The advent of second-generation sequencing technologies, improvements in computing algorithms and infrastructure and growth in bioinformatics and genomics literacy is making the addition of genome sequencing to the research goals of any nematode research program a less daunting prospect. To inspire, promote and coordinate genomic sequencing across the diversity of the phylum, we have launched a community wiki and the 959 Nematode Genomes initiative (www.nematodegenomes.org/). Just as the deciphering of the developmental lineage of the 959 cells of the adult hermaphrodite C. elegans was the gateway to broad advances in biomedical science, we hope that a nematode phylogeny with (at least) 959 sequenced species will underpin further advances in understanding the origins of parasitism, the dynamics of genomic change and the adaptations that have made Nematoda one of the most successful animal phyla. PMID:24058822

  1. Neuroparasitic Infections: Nematodes

    PubMed Central

    Walker, M.D.; Zunt, J.R.

    2009-01-01

    Globalization has produced an increase in the number of people at risk for contracting parasitic infection. Central nervous system infection by nematodal parasites can be devastating. Early recognition and treatment of infection can significantly decrease morbidity of the parasitic infection, as well as the risk of secondary superinfection. The clinical presentation, diagnosis, and treatment for five of the more common nematodal infections of the nervous system—Angiostrongylus spp., Baylisacaris procyonis, Gnathostoma spinigerum, Strongyloides stercoralis, and Toxocara spp.—is reviewed. Objectives On completion of this article, the reader should be able to summarize the clinical presentation, diagnosis, and treatment of the common nematodal infections of the nervous system. Accreditation The Indiana University School of Medicine is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. Credit The Indiana University School of Medicine designates this educational activity for a maximum of 1 Category 1 credit toward the AMA Physicians Recognition Award. Each physician should claim only those credits that he/she actually spent in the educational activity. Disclosure Statements of disclosure have been obtained regarding the authors’ relevant financial relationships. The authors have nothing to disclose. PMID:16170738

  2. Naturally Acquired Binding-Inhibitory Antibodies to Plasmodium vivax Duffy Binding Protein in Pregnant Women Are Associated with Higher Birth Weight in a Multicenter Study

    PubMed Central

    Requena, Pilar; Arévalo-Herrera, Myriam; Menegon, Michela; Martínez-Espinosa, Flor E.; Padilla, Norma; Bôtto-Menezes, Camila; Malheiro, Adriana; Hans, Dhiraj; Castellanos, Maria Eugenia; Robinson, Leanne; Samol, Paula; Kochar, Swati; Kochar, Sanjay K.; Kochar, Dhanpat K.; Desai, Meghna; Sanz, Sergi; Quintó, Llorenç; Mayor, Alfredo; Rogerson, Stephen; Mueller, Ivo; Severini, Carlo; del Portillo, Hernando A.; Bardají, Azucena; Chitnis, Chetan C.; Menéndez, Clara; Dobaño, Carlota

    2017-01-01

    A vaccine to eliminate malaria would need a multi-stage and multi-species composition to achieve robust protection, but the lack of knowledge about antigen targets and mechanisms of protection precludes the development of fully efficacious malaria vaccines, especially for Plasmodium vivax (Pv). Pregnant women constitute a risk population who would greatly benefit from a vaccine preventing the adverse events of Plasmodium infection during gestation. We hypothesized that functional immune responses against putative targets of naturally acquired immunity to malaria and vaccine candidates will be associated with protection against malaria infection and/or poor outcomes during pregnancy. We measured (i) IgG responses to a large panel of Pv and Plasmodium falciparum (Pf) antigens, (ii) the capacity of anti-Pv ligand Duffy binding protein (PvDBP) antibodies to inhibit binding to Duffy antigen, and (iii) cellular immune responses to two Pv antigens, in a subset of 1,056 pregnant women from Brazil, Colombia, Guatemala, India, and Papua New Guinea (PNG). There were significant intraspecies and interspecies correlations for most antibody responses (e.g., PfMSP119 versus PfAMA1, Spearman’s rho = 0.81). Women from PNG and Colombia had the highest levels of IgG overall. Submicroscopic infections seemed sufficient to boost antibody responses in Guatemala but not antigen-specific cellular responses in PNG. Brazil had the highest percentage of Duffy binding inhibition (p-values versus Colombia: 0.040; Guatemala: 0.047; India: 0.003, and PNG: 0.153) despite having low anti-PvDBP IgG levels. Almost all antibodies had a positive association with present infection, and coinfection with the other species increased this association. Anti-PvDBP, anti-PfMSP1, and anti-PfAMA1 IgG levels at recruitment were positively associated with infection at delivery (p-values: 0.010, 0.003, and 0.023, respectively), suggesting that they are markers of malaria exposure. Peripheral blood

  3. Naturally Acquired Binding-Inhibitory Antibodies to Plasmodium vivax Duffy Binding Protein in Pregnant Women Are Associated with Higher Birth Weight in a Multicenter Study.

    PubMed

    Requena, Pilar; Arévalo-Herrera, Myriam; Menegon, Michela; Martínez-Espinosa, Flor E; Padilla, Norma; Bôtto-Menezes, Camila; Malheiro, Adriana; Hans, Dhiraj; Castellanos, Maria Eugenia; Robinson, Leanne; Samol, Paula; Kochar, Swati; Kochar, Sanjay K; Kochar, Dhanpat K; Desai, Meghna; Sanz, Sergi; Quintó, Llorenç; Mayor, Alfredo; Rogerson, Stephen; Mueller, Ivo; Severini, Carlo; Del Portillo, Hernando A; Bardají, Azucena; Chitnis, Chetan C; Menéndez, Clara; Dobaño, Carlota

    2017-01-01

    A vaccine to eliminate malaria would need a multi-stage and multi-species composition to achieve robust protection, but the lack of knowledge about antigen targets and mechanisms of protection precludes the development of fully efficacious malaria vaccines, especially for Plasmodium vivax (Pv). Pregnant women constitute a risk population who would greatly benefit from a vaccine preventing the adverse events of Plasmodium infection during gestation. We hypothesized that functional immune responses against putative targets of naturally acquired immunity to malaria and vaccine candidates will be associated with protection against malaria infection and/or poor outcomes during pregnancy. We measured (i) IgG responses to a large panel of Pv and Plasmodium falciparum (Pf) antigens, (ii) the capacity of anti-Pv ligand Duffy binding protein (PvDBP) antibodies to inhibit binding to Duffy antigen, and (iii) cellular immune responses to two Pv antigens, in a subset of 1,056 pregnant women from Brazil, Colombia, Guatemala, India, and Papua New Guinea (PNG). There were significant intraspecies and interspecies correlations for most antibody responses (e.g., PfMSP119 versus PfAMA1, Spearman's rho = 0.81). Women from PNG and Colombia had the highest levels of IgG overall. Submicroscopic infections seemed sufficient to boost antibody responses in Guatemala but not antigen-specific cellular responses in PNG. Brazil had the highest percentage of Duffy binding inhibition (p-values versus Colombia: 0.040; Guatemala: 0.047; India: 0.003, and PNG: 0.153) despite having low anti-PvDBP IgG levels. Almost all antibodies had a positive association with present infection, and coinfection with the other species increased this association. Anti-PvDBP, anti-PfMSP1, and anti-PfAMA1 IgG levels at recruitment were positively associated with infection at delivery (p-values: 0.010, 0.003, and 0.023, respectively), suggesting that they are markers of malaria exposure. Peripheral blood mononuclear

  4. Intestinal nematodes: biology and control.

    PubMed

    Epe, Christian

    2009-11-01

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

  5. New frontiers in nematode ecology.

    PubMed

    Ferris, H

    1993-09-01

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

  6. New Frontiers in Nematode Ecology

    PubMed Central

    Ferris, Howard

    1993-01-01

    Future areas of emphasis for research and scholarship in nematode ecology are indicated by pressing agricultural and environmental issues, by new directions in applied nematology, and by current technological advances. Studies in nematode ecology must extend beyond observation, counting, and simple statistical analysis. Experimentation and the testing of hypotheses are needed for understanding the biological mechanisms of ecological systems. Opportunities for fruitful experimentation in nematode ecology are emerging at the ecosystem, community, population, and individual levels. Nematode ecologists will best promote their field of study by closely monitoring and participating in the advances, initiatives, developments, and directions in the larger field of ecology. PMID:19279783

  7. Characterization of a pathogen-induced potato catalase and its systemic expression upon nematode and bacterial infection.

    PubMed

    Niebel, A; Heungens, K; Barthels, N; Inzé, D; Van Montagu, M; Gheysen, G

    1995-01-01

    We have isolated a cDNA encoding a catalase (Cat2St) by differential screening of a cDNA library constructed from potato roots infected with the cyst nematode Globodera pallida. Expression analysis confirmed the local induction of Cat2St and showed that it was highest at the adult stage of the parasite. It also revealed that Cat2St was induced in uninfected roots, stems, and leaves of infected plants. Localized and systemic induction of Cat2St was also observed upon root-knot nematode (Meloidogyne incognita) and root bacteria (Erwinia carotovora, Corynebacterium sepedonicum) infections. Based on sequence and expression analysis, Cat2St was found to belong to the recently described class II of dicotyledonous catalases, suggesting that these catalase isoforms could also be pathogen induced. Plant-parasitic nematodes are known to induce, in the roots of their hosts, highly metabolic feeding cells that function as nutritional sinks. Whereas the local induction of Cat2St is probably a consequence of an oxidative stress of metabolic nature, the systemic induction of Cat2St shows striking similarities with the induction of systemic acquired resistance (SAR) genes. The possible role of catalase in compatible plant-pathogen interactions is discussed.

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

    PubMed

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

    2012-06-01

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

  9. Reflections on Plant and Soil Nematode Ecology: Past, Present and Future

    PubMed Central

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

    2012-01-01

    The purpose of this review is to highlight key developments in nematode ecology from its beginnings to where it stands today as a discipline within nematology. Emerging areas of research appear to be driven by crop production constraints, environmental health concerns, and advances in technology. In contrast to past ecological studies which mainly focused on management of plant-parasitic nematodes, current studies reflect differential sensitivity of nematode faunae. These differences, identified in both aquatic and terrestrial environments include response to stressors, environmental conditions, and management practices. Methodological advances will continue to influence the role nematodes have in addressing the nature of interactions between organisms, and of organisms with their environments. In particular, the C. elegans genetic model, nematode faunal analysis and nematode metagenetic analysis can be used by ecologists generally and not restricted to nematologists. PMID:23482864

  10. Efficacy of oral rehydration therapy solutions containing sodium bicarbonate or sodium acetate for treatment of calves with naturally acquired diarrhea, moderate dehydration, and strong ion acidosis.

    PubMed

    Sen, Ismail; Altunok, Vahdettin; Ok, Mahmut; Coskun, Alparslan; Constable, Peter D

    2009-04-01

    To determine and compare the effects of 4 oral replacement therapy (ORT) solutions on acid-base balance, abomasal emptying rate, and plasma volume expansion in calves with naturally acquired diarrhea and moderate dehydration. Prospective study. 20 calves. 20 calves up to 45 days of age were randomly allocated (n = 5/group) to receive 2 L of 1 of 4 treatments via oroesophageal intubation: sodium bicarbonate (150 mmol/L or 300 mmol/L) or sodium acetate (150 mmol/L or 300 mmol/L). The 4 test solutions contained acetaminophen (50 mg/kg [22.7 mg/lb]) and 50 g of glucose monohydrate. Jugular venous blood samples were obtained periodically before and after administration of the ORT solution. Abomasal emptying rate was determined by use of the time to maximal plasma acetaminophen concentration. Plasma bicarbonate concentration increased more rapidly in calves administered bicarbonate-containing ORT solutions, whereas the rate of systemic alkalinization, as assessed via blood pH, did not differ consistently among treatments. The 300 mmol/L ORT solutions were emptied at a significantly slower rate from the abomasum than 150 mmol/L ORT solutions, with no difference in emptying rate between acetate and bicarbonate-containing ORT solutions of similar molality. The 300 mmol/L sodium acetate ORT solution significantly increased plasma volume. Clinically important differences in the resuscitative response to 300 mmol/L or 150 mmol/L ORT solutions of sodium acetate or sodium bicarbonate were not identified.

  11. Naturally acquired immune responses to malaria vaccine candidate antigens MSP3 and GLURP in Guahibo and Piaroa indigenous communities of the Venezuelan Amazon

    PubMed Central

    2012-01-01

    Background Malaria transmission in most of Latin America can be considered as controlled. In such a scenario, parameters of baseline immunity to malaria antigens are of specific interest with respect to future malaria eradication efforts. Methods A cross-sectional study was carried out in two indigenous population groups in Amazonas/Venezuela. Data from the regional malaria documentation system were extracted and participants from the ethnic groups of the Guahibo (n = 180) and Piaroa (n = 295) were investigated for the presence of Plasmodium parasites and naturally acquired antibodies to Plasmodium falciparum antigens in serum. The GMZ2 vaccine candidate proteins MSP3 and GLURP were chosen as serological markers. Results The incidence of P. falciparum in both communities was found to be less than 2%, and none of the participants harboured P. falciparum at the time of the cross-sectional. Nearly a quarter of the participants (111/475; 23,4%) had positive antibody titres to at least one of the antigens. 53/475 participants (11.2%) were positive for MSP3, and 93/475 participants (19.6%) were positive for GLURP. High positive responses were detected in 36/475 participants (7.6%) and 61/475 participants (12.8%) for MSP3 and GLURP, respectively. Guahibo participants had significantly higher antibody titres than Piaroa participants. Conclusions Considering the low incidence of P. falciparum, submicroscopical infections may explain the comparatively high anti-P. falciparum antibody concentrations. PMID:22335967

  12. Cotton Cultivar Response to Root-Knot Nematodes in Two Tillage Regimes, 2008

    USDA-ARS?s Scientific Manuscript database

    Six cotton cultivars were evaluated for yield response to the root-knot nematode in a naturally infested field at E. V. Smith Research and Extension Center, near Shorter, Alabama. The field had a long history of root-knot nematode infestation, and the soil type was classified as a sandy loam. Plots ...

  13. DYNAMICS OF NEMATODE POPULATIONS IN CACAO GROWN UNDER TRADIONALLY SYSTEM OF MANAGEMENT IN PERUVIAN AMAZON

    USDA-ARS?s Scientific Manuscript database

    Nature of crops and management systems greatly influences population dynamics of parasitic and nonparasitic nematodes in soil. An experiment was undertaken at Tropical Crop Research institute (ICT), Tarapoto, Peru to assess the population dynamics of nematodes in a Cocoa (Theobroma cacao L.)-Banana ...

  14. Managing Nematodes without Methyl Bromide

    USDA-ARS?s Scientific Manuscript database

    Methyl bromide is an effective pre-plant soil fumigant used to control nematodes in many high-input, high-value production systems including vegetables, nurseries, ornamentals, tree fruits, strawberries, and grapes. Because methyl bromide has provided a reliable return on investment for nematode c...

  15. Social networks of educated nematodes

    USDA-ARS?s Scientific Manuscript database

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

  16. Plasmodium vivax Cell-Traversal Protein for Ookinetes and Sporozoites: Naturally Acquired Humoral Immune Response and B-Cell Epitope Mapping in Brazilian Amazon Inhabitants.

    PubMed

    Rodrigues-da-Silva, Rodrigo Nunes; Soares, Isabela Ferreira; Lopez-Camacho, Cesar; Martins da Silva, João Hermínio; Perce-da-Silva, Daiana de Souza; Têva, Antônio; Ramos Franco, Antônia Maria; Pinheiro, Francimeire Gomes; Chaves, Lana Bitencourt; Pratt-Riccio, Lilian Rose; Reyes-Sandoval, Arturo; Banic, Dalma Maria; Lima-Junior, Josué da Costa

    2017-01-01

    The cell-traversal protein for ookinetes and sporozoites (CelTOS), a highly conserved antigen involved in sporozoite motility, plays an important role in the traversal of host cells during the preerythrocytic stage of Plasmodium species. Recently, it has been considered an alternative target when designing novel antimalarial vaccines against Plasmodium falciparum. However, the potential of Plasmodium vivax CelTOS as a vaccine target is yet to be explored. This study evaluated the naturally acquired immune response against a recombinant P. vivax CelTOS (PvCelTOS) (IgG and IgG subclass) in 528 individuals from Brazilian Amazon, as well as the screening of B-cell epitopes in silico and peptide assays to associate the breadth of antibody responses of those individuals with exposition and/or protection correlates. We show that PvCelTOS is naturally immunogenic in Amazon inhabitants with 94 individuals (17.8%) showing specific IgG antibodies against the recombinant protein. Among responders, the IgG reactivity indexes (RIs) presented a direct correlation with the number of previous malaria episodes (p = 0.003; r = 0.315) and inverse correlation with the time elapsed from the last malaria episode (p = 0.031; r = -0.258). Interestingly, high responders to PvCelTOS (RI > 2) presented higher number of previous malaria episodes, frequency of recent malaria episodes, and ratio of cytophilic/non-cytophilic antibodies than low responders (RI < 2) and non-responders (RI < 1). Moreover, a high prevalence of the cytophilic antibody IgG1 over all other IgG subclasses (p < 0.0001) was observed. B-cell epitope mapping revealed five immunogenic regions in PvCelTOS, but no associations between the specific IgG response to peptides and exposure/protection parameters were found. However, the epitope (PvCelTOSI136-E143) was validated as a main linear B-cell epitope, as 92% of IgG responders to PvCelTOS were also responders to this peptide sequence. This

  17. Plasmodium vivax Cell-Traversal Protein for Ookinetes and Sporozoites: Naturally Acquired Humoral Immune Response and B-Cell Epitope Mapping in Brazilian Amazon Inhabitants

    PubMed Central

    Rodrigues-da-Silva, Rodrigo Nunes; Soares, Isabela Ferreira; Lopez-Camacho, Cesar; Martins da Silva, João Hermínio; Perce-da-Silva, Daiana de Souza; Têva, Antônio; Ramos Franco, Antônia Maria; Pinheiro, Francimeire Gomes; Chaves, Lana Bitencourt; Pratt-Riccio, Lilian Rose; Reyes-Sandoval, Arturo; Banic, Dalma Maria; Lima-Junior, Josué da Costa

    2017-01-01

    The cell-traversal protein for ookinetes and sporozoites (CelTOS), a highly conserved antigen involved in sporozoite motility, plays an important role in the traversal of host cells during the preerythrocytic stage of Plasmodium species. Recently, it has been considered an alternative target when designing novel antimalarial vaccines against Plasmodium falciparum. However, the potential of Plasmodium vivax CelTOS as a vaccine target is yet to be explored. This study evaluated the naturally acquired immune response against a recombinant P. vivax CelTOS (PvCelTOS) (IgG and IgG subclass) in 528 individuals from Brazilian Amazon, as well as the screening of B-cell epitopes in silico and peptide assays to associate the breadth of antibody responses of those individuals with exposition and/or protection correlates. We show that PvCelTOS is naturally immunogenic in Amazon inhabitants with 94 individuals (17.8%) showing specific IgG antibodies against the recombinant protein. Among responders, the IgG reactivity indexes (RIs) presented a direct correlation with the number of previous malaria episodes (p = 0.003; r = 0.315) and inverse correlation with the time elapsed from the last malaria episode (p = 0.031; r = −0.258). Interestingly, high responders to PvCelTOS (RI > 2) presented higher number of previous malaria episodes, frequency of recent malaria episodes, and ratio of cytophilic/non-cytophilic antibodies than low responders (RI < 2) and non-responders (RI < 1). Moreover, a high prevalence of the cytophilic antibody IgG1 over all other IgG subclasses (p < 0.0001) was observed. B-cell epitope mapping revealed five immunogenic regions in PvCelTOS, but no associations between the specific IgG response to peptides and exposure/protection parameters were found. However, the epitope (PvCelTOSI136-E143) was validated as a main linear B-cell epitope, as 92% of IgG responders to PvCelTOS were also responders to this peptide sequence. This

  18. Comparison of the effects of imidapril and enalapril in a prospective, multicentric randomized trial in dogs with naturally acquired heart failure.

    PubMed

    Amberger, Chris; Chetboul, Valérie; Bomassi, Eric; Rougier, Sandrine; Woehrlé, Frédérique; Thoulon, Fabrice

    2004-11-01

    To compare the efficacy and tolerability of the long-term administration of two different angiotensin-converting enzyme inhibitors, imidapril and enalapril, in a multicentric, prospective, randomized parallel-group scheme clinical trial in dogs with naturally acquired heart disease. One hundred twenty eight dogs with clinical signs of heart failure (stage II (64-50%) - III (45-35%) - IV (19-15%) New York Heart Association) caused by chronic valvular disease or dilated cardiomyopathy were selected. Imidapril (minimum dosage 0.25 mg/kg) or enalapril (median dosage 0.5 mg/kg) was administered orally once daily for 12 months, either alone or as an add-on therapy to diuretics and/or digoxin. The primary outcome measure was the quality of life score after 3 months of therapy. Sixty-one percent of the dogs in the imidapril group (36/59) and 52 % in the enalapril group (30/58) were considered responders. After 12 months, a clear improvement compared to baseline was maintained in each treatment group for most parameters reflecting the quality of life such as fatigue, exercise tolerance, dyspnea, cough and general condition. Quality of life scores and survival times were similar in both groups after 12 months. Both drugs were well tolerated over the one-year follow-up. Imidapril proved to be as effective as the reference drug enalapril in the treatment of dogs with NYHA class II-IV heart failure. As with enalapril, imidapril was well tolerated during the long-term treatment period of one year in the dose range used in the study.

  19. Interactions of microfungi and plant parasitic nematodes

    USDA-ARS?s Scientific Manuscript database

    Plant parasitic nematodes and microfungi inhabit many of the same ecological habitats and interact in almost every conceivable way. Nematodes can feed on fungi, and conversely fungi can use nematodes as a food source. Fungi have been widely studied as biological controls of plant parasitic nematod...

  20. Anthelmintic efficacy of oxibendazole against some important nematodes in dogs and cats.

    PubMed

    Overgaauw, P A; Boersema, J H

    1998-04-01

    The anthelmintic efficacy and safety of the oxibendazole component in a combination oxibendazole-niclosamide paste were investigated in dogs and cats and in litters of pups with naturally acquired nematode infections. A single dose of 15 mg oxibendazole/kg body weight given to 70 dogs and to 29 cats reduced faecal worm egg counts (EPG) by 97.6% for Toxocara canis, 95.7% for Trichuris vulpis, 94.6% for Ancylostoma caninum, and 100% for Toxascaris leonina. In cats, 96.7% efficacy was demonstrated against Toxocara cati. In a second trial, 119 pups in 22 litters were treated with the same dosage at 2, 4, and 6 weeks of age. After treatment on two consecutive days, 95% of the pups did not shed T. canis eggs, compared with 85% after only a single treatment. Side effects were rare and only recorded in young animals. A 2-day treatment schedule is recommended for unweaned pups.

  1. Condensed tannins act against cattle nematodes.

    PubMed

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

    2011-12-15

    The use of natural plant anthelmintics was suggested as a possible alternative control of gastrointestinal nematodes (GIN) in ruminants. Direct anthelmintic effects of tannin-containing plants have already been shown in sheep and goat GIN. These anthelmintic properties are mainly associated with condensed tannins. In the present study, we evaluated possible in vitro effects of three tannin-containing plants against bovine GIN. Effects of Onobrychis viciifolia, Lotus pedunculatus and Lotus corniculatus condensed tannin (CT) extracts on Cooperia oncophora and Ostertagia ostertagi were determined by a larval feeding inhibition assay (LFIA) and a larval exsheathment assay (LEA). In the LFIA, all three plant extracts significantly inhibited larval feeding behaviour of both C. oncophora and O. ostertagi first stage larvae in a dose-dependent manner. The L. pedunculatus extract, based on EC(50) (effective concentration for 50% inhibition), was the most effective against both nematodes, followed by O. viciifolia and L. corniculatus. The effect of CT extracts upon larval feeding behaviour correlates with CT content and procyanidin/prodelphidin ratio. Larval exsheathment of C. oncophora and O. ostertagi L3 larvae (third stage larvae) was also affected by CT extracts from all three plants. In both in vitro assays, extracts with added polyvinylpolypyrrolidone, an inhibitor of tannins, generated almost the same values as the negative control; this confirms the role of CT in the anthelmintic effect of these plant extracts. Our results, therefore, indicated that tannin-containing plants could act against cattle nematodes. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Identification and analysis of insulin like peptides in nematode secretomes provide targets for parasite control

    PubMed Central

    Gahoi, Shachi; Gautam, Budhayash

    2016-01-01

    Insulin-like (ins) peptides play an important role in development and metabolism across the metazoa. In nematodes, these are also required for dauer formation and longevity and are expressed in different types of neurons across various life stages which demonstrate their role in parasites and could become possible targets for parasite control. To date, many nematode genomes are publically available. However, a systematic screening of ins peptides across different nematode group has not been reported. In the present study, we systematically identified ins peptides in the secretomes of 73 nematodes with fully sequenced genomes covering five different groups viz. plant parasitic, animal parasitic, human parasitic, entomopathogenic and free living nematodes. From the total of 93,949 secretory proteins, 176 proteins were uniquely mapped to 40 identified C. elegans ins families. The obtained result showed that 74.15% of the identified ins proteins were represented in free living nematodes only and remaining 25.84% were combinedly identified in all other nematode groups. The ins-1, ins-17 and ins-18 were the only ins families which were detected in all the studied nematode groups. Out of 176 proteins, 96 of ins proteins were predicted as hydrophilic in nature and 39 proteins were found stable using ProtParam analysis. Our study provides insight into the distribution of ins peptides across different group of nematodes and this information could be useful for further experimental study. PMID:28356679

  3. The white-nosed coati (Nasua narica) is a naturally susceptible definitive host for the zoonotic nematode Angiostrongylus costaricensis in Costa Rica.

    PubMed

    Santoro, Mario; Alfaro-Alarcón, Alejandro; Veneziano, Vincenzo; Cerrone, Anna; Latrofa, Maria Stefania; Otranto, Domenico; Hagnauer, Isabel; Jiménez, Mauricio; Galiero, Giorgio

    2016-09-15

    Angiostrongylus costaricensis (Strongylida, Angiostrongylidae) is a roundworm of rodents, which may cause a severe or fatal zoonosis in several countries of the Americas. A single report indicated that the white-nosed coati (Nasua narica), acts as a potential free-ranging wildlife reservoir. Here we investigated the prevalence and features of A. costaricensis infection in two procyonid species, the white-nosed coati and the raccoon (Procyon lotor) from Costa Rica to better understand their possible role in the epidemiology of this zoonotic infection. Eighteen of 32 (56.2%) white-nosed coatis collected between July 2010 and March 2016 were infected with A. costaricensis but none of 97 raccoons from the same localities were diagnosed with this infection. First-stage larvae of A. costaricensis were obtained from feces of 17 fresh white-nosed coati carcasses by Baermann technique. Parasite identity was confirmed by morphology, histology and molecular characterization of target genes. These data demonstrate that the white-nosed coati is a naturally susceptible definitive host for A. costaricensis in Costa Rica contrary to findings in the raccoon. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Anthelmintic efficacy of ivermectin and abamectin, administered orally for seven consecutive days (100 µg/kg/day), against nematodes in naturally infected pigs.

    PubMed

    Lopes, Welber Daniel Zanetti; Teixeira, Weslen Fabricio Pires; Felippelli, Gustavo; Cruz, Breno Cayeiro; Buzulini, Carolina; Maciel, Willian Giquelin; Fávero, Flávia Carolina; Gomes, Lucas Vinicius Costa; Prando, Luciana; Bichuette, Murilo A; Dos Santos, Thais Rabelo; da Costa, Alvimar José

    2014-12-01

    The present study aimed to evaluate ivermectin and abamectin, both administered orally in naturally infected domestic swine, as well as analysing if the EPG (eggs per gram of faeces) values were equivalent with the ivermectin and abamectin efficacy obtained by parasitological necropsies. The animals were randomly selected based on the average of three consecutive EPG counts of Strongylida, Ascaris suum and Trichuris for experiment I, and of Strongylida and Trichuris for experiment II. After the random draw, eight animals were treated, orally, during seven consecutive days with 100 µg/kg/day ivermectin (Ivermectina® premix, Ouro Fino Agronegócios), eight other animals were treated, orally, during seven consecutive days with 100 µg/kg/day abamectin (Virbamax® premix - Virbac do Brasil Indústria e Comércio Ltda.), and eight pigs were kept as controls. EPG counts were performed for each individual animal at 14th day post-treatment (DPT). All animals (control and treatment) were necropsied at the 14th DPT. The results from both experiments demonstrate that both ivermectin and abamectin, administered orally for a continuous period of seven days, at a daily dosage of 100 µg/kg, were highly effective (>95%) against Hyostrongylus rubidus, Strongyloides ransomi, Ascaris suum and Metastrongylus salmi. Against Oesophagostomum dentatum, abamectin presented over 95% efficacy against both evaluated strains, while ivermectin reached other strain as resistant. Regarding T. suis, both ivermectin and abamectin were effective (efficacies >90%) against one of the tested strains, while the other one was classified as resistant. Furthermore, the EPG values were equivalent with the ivermectin and abamectin efficacy obtained by parasitological necropsies.

  5. Genomic and Molecular Characterization of Miltefosine Resistance in Leishmania infantum Strains with Either Natural or Acquired Resistance through Experimental Selection of Intracellular Amastigotes

    PubMed Central

    Hendrickx, Sarah; Eberhardt, Eline; Garcia-Hernandez, Raquel; Lachaud, Laurence; Cotton, James; Sanders, Mandy; Cuypers, Bart; Imamura, Hideo; Dujardin, Jean-Claude; Delputte, Peter; Cos, Paul; Caljon, Guy; Gamarro, Francisco; Castanys, Santiago

    2016-01-01

    During the last decade miltefosine (MIL) has been used as first-line treatment for visceral leishmaniasis in endemic areas with antimonial resistance, but a decline in clinical effectiveness is now being reported. While only two MIL-resistant Leishmania infantum strains from HIV co-infected patients have been documented, phenotypic MIL-resistance for L. donovani has not yet been identified in the laboratory. Hence, a better understanding of the factors contributing to increased MIL-treatment failure is necessary. Given the paucity of defined MIL-resistant L. donovani clinical isolates, this study used an experimental amastigote-selected MIL-resistant L. infantum isolate (LEM3323). In-depth exploration of the MIL-resistant phenotype was performed by coupling genomic with phenotypic data to gain insight into gene function and the mutant phenotype. A naturally MIL-resistant L. infantum clinical isolate (LEM5159) was included to compare both datasets. Phenotypically, resistance was evaluated by determining intracellular amastigote susceptibility in vitro and actual MIL-uptake. Genomic analysis provided supportive evidence that the resistance selection model on intracellular amastigotes can be a good proxy for the in vivo field situation since both resistant strains showed mutations in the same inward transporter system responsible for the acquired MIL-resistant phenotype. In line with previous literature findings in promastigotes, our data confirm a defective import machinery through inactivation of the LiMT/LiRos3 protein complex as the main mechanism for MIL-resistance also in intracellular amastigotes. Whole genome sequencing analysis of LEM3323 revealed a 2 base pair deletion in the LiMT gene that led to the formation an early stop codon and a truncation of the LiMT protein. Interestingly, LEM5159 revealed mutations in both the LiMT and LiRos3 genes, resulting in an aberrant expression of the LiMT protein. To verify that these mutations were indeed accountable for

  6. Composition of the Cockroach Gut Microbiome in the Presence of Parasitic Nematodes

    PubMed Central

    Vicente, Cláudia S. L.; Ozawa, Sota; Hasegawa, Koichi

    2016-01-01

    Cockroaches are parasitized by thelastomatid nematodes, which live in an obligate manner in their hindgut and interact with the resident microbial community. In the present study, a composition analysis was performed on the gut microbiome of Periplaneta fuliginosa and P. americana to investigate natural and artificial infection by thelastomatid nematodes. Nine libraries of the 16S rRNA gene V3–V4 region were prepared for pyrosequencing. We examined the complete gut microbiome (fore-, mid-, and hindgut) of lab-reared P. fuliginosa naturally infected with the parasitic nematode Leidynema appendiculatum and those that were nematode-free, and complemented our study by characterizing the hindgut microbial communities of lab-reared P. americana naturally infected with Hammerschmidtiella diesingi and Thelastoma bulhoesi, artificially infected with L. appendiculatum, and those that were nematode-free. Our results revealed that the fore- and midgut of naturally infected and nematode-free P. fuliginosa have close microbial communities, which is in contrast with hindgut communities; the hindgut communities of both cockroaches exhibit higher microbial diversities in the presence of their natural parasites and marked differences were observed in the abundance of the most representative taxa, namely Firmicutes, Proteobacteria, and Bacteroidetes. Our results have provided basic information and encourage further studies on multitrophic interactions in the cockroach gut as well as the thelastomatid nematodes that play a role in this environment. PMID:27524304

  7. The Role of Age and Exposure to Plasmodium falciparum in the Rate of Acquisition of Naturally Acquired Immunity: A Randomized Controlled Trial

    PubMed Central

    Guinovart, Caterina; Dobaño, Carlota; Bassat, Quique; Nhabomba, Augusto; Quintó, Llorenç; Manaca, Maria Nélia; Aguilar, Ruth; Rodríguez, Mauricio H.; Barbosa, Arnoldo; Aponte, John J.; Mayor, Alfredo G.; Renom, Montse; Moraleda, Cinta; Roberts, David J.; Schwarzer, Evelin; Le Souëf, Peter N.; Schofield, Louis; Chitnis, Chetan E.; Doolan, Denise L.; Alonso, Pedro L.

    2012-01-01

    Background The rate of acquisition of naturally acquired immunity (NAI) against malaria predominantly depends on transmission intensity and age, although disentangling the effects of these is difficult. We used chemoprophylaxis to selectively control exposure to P. falciparum during different periods in infancy and explore the effect of age in the build-up of NAI, measured as risk of clinical malaria. Methods and Findings A three-arm double-blind randomized placebo-controlled trial was conducted in 349 infants born to Mozambican HIV-negative women. The late exposure group (LEG) received monthly Sulfadoxine-Pyrimethamine (SP) plus Artesunate (AS) from 2.5–4.5 months of age and monthly placebo from 5.5–9.5 months; the early exposure group (EEG) received placebo from 2.5–4.5 months and SP+AS from 5.5–9.5 months; and the control group (CG) received placebo from 2.5–9.5 months. Active and passive case detection (PCD) were conducted from birth to 10.5 and 24 months respectively. The primary endpoint was time to first or only episode of malaria in the second year detected by PCD. The incidence of malaria during the second year was of 0.50, 0.51 and 0.35 episodes/PYAR in the LEG, EEG and CG respectively (p = 0.379 for the adjusted comparison of the 3 groups). The hazard ratio of the adjusted comparison between the LEG and the CG was 1.38 (0.83–2.28, p = 0.642) and that between the EEG and the CG was 1.35 (0.81–2.24, p = 0.743). Conclusions After considerably interfering with exposure during the first year of life, there was a trend towards a higher risk of malaria in the second year in children who had received chemoprophylaxis, but there was no significant rebound. No evidence was found that the age of first exposure to malaria affects the rate of acquisition of NAI. Thus, the timing of administration of antimalarial interventions like malaria vaccines during infancy does not appear to be a critical determinant. Trial Registration Clinical

  8. An alkalinizing oral rehydration solution containing lecithin-coated citrus fiber is superior to a nonalkalinizing solution in treating 360 calves with naturally acquired diarrhea.

    PubMed

    Goodell, G M; Campbell, J; Hoejvang-Nielsen, L; Stansen, W; Constable, P D

    2012-11-01

    The aim of this field study was to compare the efficacy and cost of 2 commercially available oral rehydration therapy (ORT) solutions in treating dairy calves with naturally acquired diarrhea. A total of 1,349 newborn Holstein-Friesian calves were prospectively enrolled in the study. Calves were housed in individual hutches and fed a mixture of pasteurized hospital milk and an all-milk protein milk replacer twice per day. Calves were monitored twice each day from d 2 of life until 30 d of age for the presence or absence of diarrhea, and were assigned a fecal score and a hydration score at each examination. Calves that developed mild to severe diarrhea that did not need intravenous fluids and did not have clinical evidence of concurrent disease (n = 360) were assigned randomly to receive 1 of 2 commercial ORT solutions: a hypertonic alkalinizing ORT containing lecithin-coated citrus fibers (Diaque, group D, n = 180; Boehringer Ingelheim, Ingelheim, Germany), and an isotonic nonalkalinizing ORT (RE-SORB, group R, n = 180; Pfizer Animal Health, New York, NY) for 2 to 8d; the duration of treatment depended on whether diarrhea was still present. No significant differences were observed in mortality rates or treatment failure rates between the 2 treatment groups. Fecal consistency returned to normal more quickly in group D calves than in group R calves; consequently, group D calves were treated for 1d less than were group R calves. The increase in body weight after 4d of treatment was larger in group D than in group R. The average daily gain from birth to weaning in calves that did not develop concurrent disease (such as pneumonia) during the study period tended to be higher in group D calves (0.53±0.11 kg/d) than in group R calves (0.51±0.09 kg/d). The smaller number of treatments at a lower cost per treatment produced a cost advantage of $4.82 per treated calf in group D calves compared with group R calves. Our findings support the concept that milk should continue

  9. Nematode burdens of pastured cattle treated once at turnout with eprinomectin extended-release injection.

    PubMed

    Rehbein, S; Baggott, D G; Johnson, E G; Kunkle, B N; Yazwinski, T A; Yoon, S; Cramer, L G; Soll, M D

    2013-03-01

    The efficacy of eprinomectin in an extended-release injection (ERI) formulation was evaluated against infections with third-stage larvae or eggs of gastrointestinal and pulmonary nematodes in cattle under 120-day natural challenge conditions in a series of five studies conducted in the USA (three studies) and in Europe (two studies). For each study, 30 nematode-free (four studies) or 30 cattle harboring naturally acquired nematode infections (one study) were included. The cattle were of various breeds or crosses, weighed 107.5-273 kg prior to treatment and aged approximately 4-11 months. For each study, animals were blocked based on pre-treatment bodyweight and then randomly allocated to treatment: ERI vehicle (control) at 1 mL/50 kg bodyweight or Eprinomectin 5% (w/v) ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg) for a total of 15 and 15 animals in each group. Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. In each study, all animals grazed one naturally contaminated pasture for 120 days. At regular intervals during the studies, fecal samples from all cattle were examined for nematode egg and larval counts. In four studies pairs of tracer cattle were used to monitor pasture infectivity at 28-day intervals before and/or during the grazing period. All calves were weighed before turnout onto pasture and at regular intervals until housing on Day 120. For parasite recovery, all study animals were humanely euthanized 27-30 days after removal from pasture. Cattle treated with Eprinomectin ERI had significantly (p<0.05) fewer strongylid eggs (≤1 egg per gram; egg count reduction≥94%) than the control cattle and zero lungworm larvae at each post-treatment time point. At euthanasia, cattle treated with Eprinomectin ERI had significantly (p<0.05) fewer of the following nematodes than the ERI vehicle-treated (control) cattle with overall reduction of nematode counts by >92%: Dictyocaulus viviparus (adults and fourth

  10. Nematode Chemosensilla: Form and Function

    PubMed Central

    Wright, K. A.

    1983-01-01

    As an introduction to a symposium of nematode chemoreception, the anatomy of nematode chemosensilla, their distribution on plant parasitic nematodes, and their possible functional roles is briefly reviewed. Comparison of nematode chemosensilla with those of other animals shows their greater resemblance to olfactory primary sense cells of vertebrates. Although the sensory process is obviously derived from a cilium, the absence of many ciliary features is noted. Retention of the ciliary necklace may be important functionally. A simple model is proposed, wherein binding of stimulant molecules to receptors in the membrane of the cilium-derived process results in entry of Na⁺ and Ca⁺⁺ (the latter via the ciliary necklace) to produce a receptor potential that spreads along the dendrite to the cell body where action potentials continue along the short axon to synapses. PMID:19295785

  11. Social Networks of Educated Nematodes

    PubMed Central

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

    2015-01-01

    Entomopathogenic nematodes are obligate lethal parasitoids of insect larvae that navigate a chemically complex belowground environment while interacting with their insect hosts, plants, and each other. In this environment, prior exposure to volatile compounds appears to prime nematodes in a compound specific manner, increasing preference for volatiles they previously were exposed to and decreasing attraction to other volatiles. In addition, persistence of volatile exposure influences this response. Longer exposure not only increases preference, but also results in longer retention of that preference. These entomopathogenic nematodes display interspecific social behavioral plasticity; experienced nematodes influence the behavior of different species. This interspecific social behavioral plasticity suggests a mechanism for rapid adaptation of belowground communities to dynamic environments. PMID:26404058

  12. Social Networks of Educated Nematodes.

    PubMed

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

    2015-09-25

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

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

    USDA-ARS?s Scientific Manuscript database

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

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

    Treesearch

    Alex L. Shigo; George Yelenosky

    1960-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  16. Studies onPaecilomyces marquandii from nematode suppressive chinampa soils.

    PubMed

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

    1992-05-01

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

  17. Functional roles of effectors of plant-parasitic nematodes.

    PubMed

    Haegeman, Annelies; Mantelin, Sophie; Jones, John T; Gheysen, Godelieve

    2012-01-15

    Plant pathogens have evolved a variety of different strategies that allow them to successfully infect their hosts. Plant-parasitic nematodes secrete numerous proteins into their hosts. These proteins, called effectors, have various functions in the plant cell. The most studied effectors to date are the plant cell wall degrading enzymes, which have an interesting evolutionary history since they are believed to have been acquired from bacteria or fungi by horizontal gene transfer. Extensive genome, transcriptome and proteome studies have shown that plant-parasitic nematodes secrete many additional effectors. The function of many of these is less clear although during the last decade, several research groups have determined the function of some of these effectors. Even though many effectors remain to be investigated, it has already become clear that they can have very diverse functions. Some are involved in suppression of plant defences, while others can specifically interact with plant signalling or hormone pathways to promote the formation of nematode feeding sites. In this review, the most recent progress in the understanding of the function of plant-parasitic nematode effectors is discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

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

    PubMed

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

    2012-12-01

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

  19. The Nature of Small Business. Unit 2. Level 2. Instructor Guide. PACE: Program for Acquiring Competence in Entrepreneurship. Third Edition. Research & Development Series No. 302-02.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This instructor guide for a unit on small business in the PACE (Program for Acquiring Competence in Entrepreneurship) curriculum includes the full text of the student module and lesson plans, instructional suggestions, and other teacher resources. The competencies that are incorporated into this module are at Level 2 of learning--planning for a…

  20. The Geological Record of Parasitic Nematode Evolution.

    PubMed

    Poinar, George O

    2015-01-01

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

  1. Orsay, Santeuil and Le Blanc viruses primarily infect intestinal cells in Caenorhabditis nematodes.

    PubMed

    Franz, Carl J; Renshaw, Hilary; Frezal, Lise; Jiang, Yanfang; Félix, Marie-Anne; Wang, David

    2014-01-05

    The discoveries of Orsay, Santeuil and Le Blanc viruses, three viruses infecting either Caenorhabditis elegans or its relative Caenorhabditis briggsae, enable the study of virus-host interactions using natural pathogens of these two well-established model organisms. We characterized the tissue tropism of infection in Caenorhabditis nematodes by these viruses. Using immunofluorescence assays targeting proteins from each of the viruses, and in situ hybridization, we demonstrate viral proteins and RNAs localize to intestinal cells in larval stage Caenorhabditis nematodes. Viral proteins were detected in one to six of the 20 intestinal cells present in Caenorhabditis nematodes. In Orsay virus-infected C. elegans, viral proteins were detected as early as 6h post-infection. The RNA-dependent RNA polymerase and capsid proteins of Orsay virus exhibited different subcellular localization patterns. Collectively, these observations provide the first experimental insights into viral protein expression in any nematode host, and broaden our understanding of viral infection in Caenorhabditis nematodes.

  2. Nematode-induced endoreduplication in plant host cells: why and how?

    PubMed

    de Almeida Engler, Janice; Gheysen, Godelieve

    2013-01-01

    Plant-parasitic root-knot and cyst nematodes have acquired the ability to induce remarkable changes in host cells during the formation of feeding sites. Root-knot nematodes induce several multinucleate giant cells inside a gall whereas cyst nematodes provoke the formation of a multinucleate syncytium. Both strategies impinge on the deregulation of the cell cycle, involving a major role for endoreduplication. This review will first describe the current knowledge on the control of normal and aberrant cell cycles. Thereafter, we will focus on the role of both cell-cycle routes in the transformation process of root cells into large and highly differentiated feeding sites as induced by the phytoparasitic root-knot and cyst nematodes.

  3. An evolutionary perspective on gastrointestinal nematodes of sheep.

    PubMed

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

    2011-06-01

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

  4. [Structural characteristics of soil nematodes community under different land uses in Changchun City].

    PubMed

    Wu, Donghui; Zhang, Bai; Chen, Peng

    2006-03-01

    In this paper, an investigation on the species richness and abundance of soil nematodes in farmland, natural secondary forest, shelter forest and green space was made in Changchun City in July and September, 2003. Soil nematodes were extracted with Baermann extractor, and identified to the genus level with the aid of microscope. A total of 7273 soil nematode individuals were captured, and fell into 2 classes, 7 orders, 20 families, and 27 genera. Aphelenchus, Tylenchus and Pratylenchus were the dominant genera, which accounted for 61.58% of total individuals. Land use type had a significant effect on the community structure of soil nematodes, and aboveground litter removal and cultivation activity were the main factors affecting soil nematodes community structure. Above-ground litter removal considerably decreased soil nematodes individual density and community diversity, while cultivation activity changed the vertical distribution of soil nematodes individual density in the soil profile. Above-ground vegetation structure and landscape pattern appeared to have little effect on the ecological structure of soil nematodes community.

  5. Nematicide impacts on nematodes and feedbacks on plant productivity in a plant diversity gradient

    NASA Astrophysics Data System (ADS)

    Eisenhauer, Nico; Ackermann, Michael; Gass, Svenja; Klier, Matthias; Migunova, Varvara; Nitschke, Norma; Ruess, Liliane; Sabais, Alexander C. W.; Weisser, Wolfgang W.; Scheu, Stefan

    2010-09-01

    A major issue in current ecological research is the effect of biodiversity on ecosystem functioning. Although several studies reported a positive diversity - productivity relationship, the role of soil animals has been largely neglected. Nematodes are among the most widespread and important herbivores causing substantial yield losses in agriculture; however, impacts of nematodes on the diversity - productivity relationship in semi-natural plant communities have not been investigated until today. In the framework of the Jena Experiment (Thuringia, Germany) we established control and nematicide treated subplots to manipulate nematode densities on plots varying in plant species (1-16) and functional group richness (1-4). We explored the interacting effects of nematicide application and plant diversity on the main trophic groups of nematodes and on aboveground plant productivity. Nematicide application reduced the number of nematodes significantly, particularly that of plant feeders and predators. The negative impact of nematicide application on plant and bacterial feeders depended however on the diversity of the plant community. Total plant shoot biomass tended to decrease in the presence of ambient nematode densities. In detail, nematode effects varied however with plant functional group identity by reducing only the shoot biomass of herbs significantly but not that of legumes. Furthermore, the shoot biomass of grasses tended to decrease in the presence of ambient nematode densities. In contrast to total shoot biomass, nematodes decreased grass shoot biomass only in high diverse but not in low diverse plant communities. Thus, the present study for the first time highlights that nematodes likely modify the community structure und functions of semi-natural plant communities by altering the competition between plant functional groups and by attenuating the diversity - productivity relationship.

  6. Nematode intestinal parasites of children in rural Guinea, Africa: prevalence and relationship to geophagia.

    PubMed

    Glickman, L T; Camara, A O; Glickman, N W; McCabe, G P

    1999-02-01

    Intestinal parasites are routinely found among children in developing countries, but the risk factors of such infection are poorly characterized. The stools of 286 randomly selected children aged 1-18 years from 3 rural villages in Guinea were examined. Data collected via questionnaire were then analyzed to assess the relationship between geophagia, the regular ingestion of soil, and infection with intestinal nematodes acquired through ingestion rather than through skin penetration. 53% of children were infected with at least 1 type of soil-transmitted nematode, and geophagia was reported by parents to occur in 57%, 53%, and 43% of children aged 1-5, 6-10, and 11-18 years, respectively. The pattern of geophagia by age and gender of the children more closely resembled the infection pattern for the 2 orally acquired and soil-transmitted nematodes Ascaris lumbricoides and Trichuris trichiura than it did the infection pattern for the 2 soil-transmitted nematodes which infect by penetrating the skin, hookworm and Strongyloides stercoralis. Geophagia is therefore an important risk factor for orally acquired nematode infections among African children, and education on geophagia prevention should be an integral component of all soil-transmitted parasite control programs.

  7. First report of a mermithid nematode infecting the invasive Megacopta cribraria (Hemiptera: Plataspidae) in the United States.

    PubMed

    Stubbins, F L; Agudelo, P; Reay-Jones, F P F; Greene, J K

    2015-05-01

    Megacopta cribraria (Hemiptera: Plataspidae) has become a pest of soybean, Glycine max (L.), in the United States. While several natural enemies of M. cribraria have been reported, our study is the first to report nematodes beneath the pleural membranes in the abdominal cavities of adults. Morphological and molecular analyses suggest this nematode belongs to the family Mermithidae. This first report of a nematode infection in M. cribraria adds to the current inventory of enemies attacking this insect. Our observations provide a basis for future research to examine the impact of nematodes on M. cribraria mortality and to investigate their capacity to reduce populations. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Parasitism of Molluscs by Nematodes: Types of Associations and Evolutionary Trends

    PubMed Central

    Grewal, P. S.; Grewal, S. K.; Tan, L.; Adams, B. J.

    2003-01-01

    Although there are no confirmed fossil records of mollusc parasitic nematodes, diverse associations of more than 108 described nematode species with slugs and snails provide a fertile ground for speculation of how mollusc parasitism evolved in nematodes. Current phylogenic resolution suggests that molluscs have been independently acquired as hosts on a number of occasions. However, molluscs are significant as hosts for only two major groups of nematodes: as intermediate hosts for metastrongyloids and as definitive hosts for a number of rhabditids. Of the 61 species of nematodes known to use molluscs as intermediate hosts, 49 belong to Metastrongyloidea (Order Strongylida); of the 47 species of nematodes that use molluscs as definitive hosts, 33 belong to the Order Rhabditida. Recent phylogenetic hypotheses have been unable to resolve whether metastrongyloids are sister taxa to those rhabditids that use molluscs as definitive hosts. Although most rhabditid nematodes have been reported not to kill their mollusc hosts prior to their reproduction, some species are pathogenic. In fact, infective juveniles of Phasmarhabditis hermaphrodita vector a lethal bacterium into the slug host in which they reproduce. This life cycle is remarkably similar to the entomopathogenic nematodes in the families Steinernematidae and Heterorhabditidae. Also, the discoveries of Alloionema and Pellioditis in slugs are interesting, as these species have been speculated to represent the ancestral forms of the entomopathogenic nematodes. Development of the infective stage appears to be an important step toward the acquisition of molluscs as definitive hosts, and the association with specific bacteria may have arisen in conjunction with the evolution of necromeny. PMID:19265989

  9. Natural infection of gastrointestinal nematodes in long-nosed armadillos Dasypus novemcinctus Linnaeus, 1758 from Pantanal wetlands, Aquidauana sub-region, Mato Grosso do Sul State, with the description of Hadrostrongylus speciosum n. gen. et n. sp. (Molineidae: Anoplostrongylinae).

    PubMed

    Lux Hoppe, Estevam G; do Nascimento, Adjair Antonio

    2007-03-15

    This study evaluated the gastrointestinal helminth fauna of long-nosed armadillos, Dasypus novemcinctus, from the Pantanal wetlands, Aquidauana sub-region, Aquidauana County, Mato Grosso do Sul State, Brazil. Thirteen species of nematodes, comprising seven genera and four families, were recovered from their gastrointestinal tracts. The following descriptors of infection were determined: prevalence, variation of intensity, average intensity and abundance. Hadrostrongylus speciosum n. gen. et n. sp. is first described here.

  10. Basic and applied research: Entomopathogenic nematodes

    USDA-ARS?s Scientific Manuscript database

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

  11. Nematode neuropeptides as transgenic nematicides

    PubMed Central

    Patten, Cheryl; Fleming, Colin C.; Maule, Aaron G.

    2017-01-01

    Plant parasitic nematodes (PPNs) seriously threaten global food security. Conventionally an integrated approach to PPN management has relied heavily on carbamate, organophosphate and fumigant nematicides which are now being withdrawn over environmental health and safety concerns. This progressive withdrawal has left a significant shortcoming in our ability to manage these economically important parasites, and highlights the need for novel and robust control methods. Nematodes can assimilate exogenous peptides through retrograde transport along the chemosensory amphid neurons. Peptides can accumulate within cells of the central nerve ring and can elicit physiological effects when released to interact with receptors on adjoining cells. We have profiled bioactive neuropeptides from the neuropeptide-like protein (NLP) family of PPNs as novel nematicides, and have identified numerous discrete NLPs that negatively impact chemosensation, host invasion and stylet thrusting of the root knot nematode Meloidogyne incognita and the potato cyst nematode Globodera pallida. Transgenic secretion of these peptides from the rhizobacterium, Bacillus subtilis, and the terrestrial microalgae Chlamydomonas reinhardtii reduce tomato infection levels by up to 90% when compared with controls. These data pave the way for the exploitation of nematode neuropeptides as a novel class of plant protective nematicide, using novel non-food transgenic delivery systems which could be deployed on farmer-preferred cultivars. PMID:28241060

  12. Application and commercialization of nematodes.

    PubMed

    Peters, Arne

    2013-07-01

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

  13. Nematode neuropeptides as transgenic nematicides.

    PubMed

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

    2017-02-01

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

  14. Impact of conservation tillage on nematode populations.

    PubMed

    Minton, N A

    1986-04-01

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

  15. Strategies for transgenic nematode control in developed and developing world crops.

    PubMed

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

    2012-04-01

    Nematodes cause an estimated $118b annual losses to world crops and they are not readily controlled by pesticides or other control options. For many crops natural resistance genes are unavailable to plant breeders or progress by this approach is slow. Transgenic plants can provide nematode resistance for such crops. Two approaches have been field trialled that control a wide range of nematodes by either limiting use of their dietary protein uptake from the crop or by preventing root invasion without a direct lethality. In addition, RNA interference increasingly in tandem with genomic studies is providing a range of potential resistance traits that involve no novel protein production. Transgenic resistance can be delivered by tissue specific promoters to just root tissues where most economic nematodes invade and feed rather than the harvested yield. High efficacy and durability can be provided by stacking nematode resistance traits including any that natural resistance provides. The constraints to uptake centre on market acceptance and not the availability of appropriate biotechnology. The need to deploy nematode resistance is intensifying with loss of pesticides, an increased need to protect crop profit margins and in many developing world countries where nematodes severely damage both commodity and staple crops.

  16. Pest management with natural products

    USDA-ARS?s Scientific Manuscript database

    The 2012 Philadelphia ACS Symposium on Natural Products for Pest Management introduced recent discoveries and applications of natural products from insect, terrestrial plant, microbial, and synthetic sources for the management of insects, weeds, plant pathogenic microbes, and nematodes. The symposiu...

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

    PubMed

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

    2014-01-01

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

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

    USGS Publications Warehouse

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

    2002-01-01

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

  19. Jasmonic acid-induced tolerance to root-knot nematodes in tomato plants through altered photosynthetic and antioxidative defense mechanisms.

    PubMed

    Bali, Shagun; Kaur, Parminder; Sharma, Anket; Ohri, Puja; Bhardwaj, Renu; Alyemeni, M N; Wijaya, Leonard; Ahmad, Parvaiz

    2017-09-13

    Plant parasitic nematodes cause severe damage to cultivated crops globally. Management of nematode population is a major concern as chemicals used as nematicides have negative impact on the environment. Natural plant products can be safely used for the control of nematodes. Among various plant metabolites, plant hormones play an essential role in developmental and physiological processes and also assist the plants to encounter stressful conditions. Keeping this in mind, the present study was designed to evaluate the effect of jasmonic acid (JA) on the growth, pigments, polyphenols, antioxidants, osmolytes, and organic acids under nematode infection in tomato seedlings. It was observed that nematode inoculation reduced the growth of seedlings. Treatment with JA improved root growth (32.79%), total chlorophylls (71.51%), xanthophylls (94.63%), anthocyanins (37.5%), and flavonoids content (21.11%) when compared to inoculated seedlings alone. The JA application enhanced the total antioxidant capacity (lipid- and water-soluble antioxidants) by 38.23 and 34.37%, respectively, in comparison to infected seedlings. Confocal studies revealed that there was higher accumulation of glutathione in hormone-treated seedlings under nematode infection. Treatment with JA increased total polyphenols content (74.56%) in comparison to nematode-infested seedlings. JA-treated seedlings also enhanced osmolyte and organic acid contents under nematode stress. Overall, treatment with JA improved growth, enhanced pigment levels, modulated antioxidant content, and enhanced osmolyte and organic acid content in nematode-infected seedlings.

  20. Evaluation of Clonostachys rosea for control of plant-parasitic nematodes in soil and in roots of carrot and wheat.

    PubMed

    Iqbal, Mudassir; Dubey, Mukesh; McEwan, Kerstin; Menzel, Uwe; Andersson Franko, Mikael; Viketoft, Maria; Funck Jensen, Dan; Karlsson, Magnus

    2017-09-12

    Biological control is a promising approach to reduce plant diseases caused by nematodes. We tested the effect of the fungus Clonostachys rosea strain IK726 inoculation on nematode community composition in a naturally nematode infested soil in a pot experiment, and the effect of C. rosea on plant health. The numbers of plant-parasitic nematode genera extracted from soil and plant roots decreased by 40 to 73 % when C. rosea was applied, while genera of non-parasitic nematodes were not affected. Soil inoculation of C. rosea increased fresh shoot weight and shoot length of wheat plants by 20 and 24 %, respectively, while only shoot dry weight increased by 48 % in carrots. Light microscopy of in vitro C. rosea - nematode interactions did not reveal evidence of direct parasitism. However, culture filtrates of C. rosea growing in potato dextrose broth, malt extract broth and synthetic nutrient broth exhibited toxicity towards nematodes and immobilised 57, 62 and 100 % of the nematodes, respectively, within 48 h. This study demonstrates that C. rosea can control plant-parasitic nematodes and thereby improve plant growth. The most likely mechanism responsible for the antagonism is antibiosis through production of nematicidal compounds, rather than direct parasitism.

  1. Nonhost Root Penetration by Soybean Cyst Nematode

    PubMed Central

    Riggs, R. D.

    1987-01-01

    A total of 66 plants in 50 species were inoculated with eggs and juveniles of soybean cyst nematode, Heterodera glycines. Roots were stained and observed for penetration and development of the nematode. Twenty-six plants were not penetrated; twenty-three were penetrated, but there was no development of the nematode; eight were penetrated with some nematode development; two were penetrated and had considerable nematode development, but few nematodes, if any, matured; and seven were penetrated with many nematodes maturing. The penetration of nonhosts may imply some susceptibility and that populations eventually would build up on the penetrated plants. Plants not penetrated may be useful as rotation plants because no reproduction would occur. PMID:19290137

  2. Compatibility of soil amendments with entomopathogenic nematodes.

    PubMed

    Bednarek, A; Gaugler, R

    1997-06-01

    The impact of inorganic and organic fertilizers on the infectivity, reproduction, and population dynamics of entomopathogenic nematodes was investigated. Prolonged (10- to 20-day) laboratory exposure to high inorganic fertilizer concentrations inhibited nematode infectivity and reproduction, whereas short (1-day) exposures increased infectivity. Heterorhabditis bacteriophora was more sensitive to adverse effects than were two species of Steinernema. In field studies, organic manure resulted in increased densities of a native population of Steinernema feltiae, whereas NPK fertilizer suppressed nematode densities regardless of manure applications. Inorganic fertilizers are likely to be compatible with nematodes in tank mixes and should not reduce the effectiveness of nematodes used for short-term control as biological insecticides, but may interfere with attempts to use nematodes as inoculative agents for long-term control. Organic manure used as fertilizer may encourage nematode establishment and recycling.

  3. Free-living nematode peptides

    USDA-ARS?s Scientific Manuscript database

    All nematodes employ a wide array of peptide messengers to control nearly all aspects of the life cycle, including hatching, locomotion, feeding, defense, mating, reproduction, and other behavioral and metabolic events. There are molecular and biological similarities, as well as significant differen...

  4. Nematode Symbiont for Photorhabdus asymbiotica

    PubMed Central

    Joyce, Susan A.; Clarke, David J.; ffrench-Constant, Richard H.; Nimmo, Graeme R.; Looke, David F.M.; Feil, Edward J.; Pearce, Lucy; Waterfield, Nick R.

    2006-01-01

    Photorhabdus asymbiotica is an emerging bacterial pathogen that causes locally invasive soft tissue and disseminated bacteremic infections in the United States and Australia. Although the source of infection was previously unknown, we report that the bacterium is found in a symbiotic association with an insect-pathogenic soil nematode of the genus Heterorhabditis. PMID:17176572

  5. Sequence data swell for nematodes.

    PubMed

    Hertz-Fowler, Christiane; Pain, Arnab

    2008-11-01

    With more than 80,000 described species that are extremely diverse in terms of ecology and biology, the Nematoda phylum is one of the most common animal phyla. This month's Genome Watch describes genomes of several nematodes, including that of the human filarial parasite Brugia malayi.

  6. Generation of transgenic plantain (Musa spp.) with resistance to plant pathogenic nematodes.

    PubMed

    Roderick, Hugh; Tripathi, Leena; Babirye, Annet; Wang, Dong; Tripathi, Jaindra; Urwin, Peter E; Atkinson, Howard J

    2012-10-01

    Plant parasitic nematodes impose a severe constraint on plantain and banana productivity; however, the sterile nature of many cultivars precludes conventional breeding for resistance. Transgenic plantain cv. Gonja manjaya (Musa AAB) plants, expressing a maize cystatin that inhibits nematode digestive cysteine proteinases and a synthetic peptide that disrupts nematode chemoreception, were assessed for their ability to resist nematode infection. Lines were generated that expressed each gene singly or both together in a stacked defence. Nematode challenge with a single species or a mixed population identified 10 lines with significant resistance. The best level of resistance achieved against the major pest species Radopholus similis was 84% ± 8% for the cystatin, 66% ± 14% for the peptide and 70% ± 6% for the dual defence. In the mixed population, trial resistance was also demonstrated to Helicotylenchus multicinctus. A fluorescently labelled form of the chemodisruptive peptide underwent retrograde transport along certain sensory dendrites of R. similis as required to disrupt chemoreception. The peptide was degraded after 30 min in simulated intestinal fluid or boiling water and after 1 h in nonsterile soil. In silico sequence analysis suggests that the peptide is not a mammalian antigen. This work establishes the mode of action of a novel nematode defence, develops the evidence for its safe and effective deployment against multiple nematode species and identifies transgenic plantain lines with a high level of resistance for a proposed field trial.

  7. DNA barcoding of parasitic nematodes: is it kosher?

    PubMed

    Siddall, Mark E; Kvist, Sebastion; Phillips, Anna; Oceguera-Figuero, Alejandro

    2012-06-01

    Nematode parasites were encountered in kosher-certified fish meat and roe, and the question was raised as to whether or not these food products were kosher as concerns food preparation standards-a matter that pertains to the identity and, by extension, the life cycle of the parasites. To ascertain the identities of parasitic nematodes, given the distorted or damaged nature of the specimens, molecular techniques were applied in the form of DNA barcoding. To our knowledge, this is the first application of this technique to an obviously cultural concern as opposed to one of health or economic significance. Results, based both on cytochrome c oxidase subunits I and II, suggested that the parasite species found in the fish products are anisakine species that do not inhabit the intestinal lumen of the fish hosts examined. Thus, there was no evidence of failure to adhere to food preparation practices consistent with the proscriptions of Orthodox Judaism. Notwithstanding the success of DNA barcoding in determining at least the higher taxonomic identities of the parasites, some shortcomings of the DNA barcoding pipeline as it pertains to nematode parasites were encountered; specifically, the paucity of data available for the DNA barcoding locus, even for very common nematode taxa.

  8. The Wolbachia endosymbiont as an anti-filarial nematode target

    PubMed Central

    Taylor, Mark J.; Foster, Jeremy M.

    2010-01-01

    Human disease caused by parasitic filarial nematodes is a major cause of global morbidity. The parasites are transmitted by arthropod intermediate hosts and are responsible for lymphatic filariasis (elephantiasis) or onchocerciasis (river blindness). Within these filarial parasites are intracellular alpha-proteobacteria, Wolbachia, that were first observed almost 30 years ago. The obligate endosymbiont has been recognized as a target for anti-filarial nematode chemotherapy as evidenced by the loss of worm fertility and viability upon antibiotic treatment in an extensive series of human trials. While current treatments with doxycycline and rifampicin are not practical for widespread use due to the length of required treatments and contraindications, anti-Wolbachia targeting nevertheless appears a promising alternative for filariasis control in situations where current programmatic strategies fail or are unable to be delivered and it provides a superior efficacy for individual therapy. The mechanisms that underlie the symbiotic relationship between Wolbachia and its nematode hosts remain elusive. Comparative genomics, bioinfomatic and experimental analyses have identified a number of potential interactions, which may be drug targets. One candidate is de novo heme biosynthesis, due to its absence in the genome sequence of the host nematode, Brugia malayi, but presence in Wolbachia and its potential roles in worm biology. We describe this and several additional candidate targets, as well as our approaches for understanding the nature of the host-symbiont relationship. PMID:20730111

  9. Efficient nematode swimming in a shear thinning colloidal suspension.

    PubMed

    Park, Jin-Sung; Kim, Daeyeon; Shin, Jennifer H; Weitz, David A

    2016-02-14

    The swimming behavior of a nematode Caenorhabditis elegans (C. elegans) is investigated in a non-Newtonian shear thinning colloidal suspension. At the onset value (ϕ∼ 8%), the suspension begins to exhibit shear thinning behavior, and the average swimming speed of worms jumps by approximately 12% more than that measured in a Newtonian solution exhibiting no shear dependent viscosity. In the shear thinning regime, we observe a gradual yet significant improvement in swimming efficiency with an increase in ϕ while the swimming speed remains nearly constant. We postulate that this enhanced swimming can be explained by the temporal change in the stroke form of the nematode that is uniquely observed in a shear thinning colloidal suspension: the nematode features a fast and large stroke in its head to overcome the temporally high drag imposed by the viscous medium, whose effective viscosity (ηs) is shown to drop drastically, inversely proportional to the strength of its stroke. Our results suggest new insights into how nematodes efficiently maneuver through the complex fluid environment in their natural habitat.

  10. A study of National Lightning Detection Network responses to natural lightning based on ground truth data acquired at LOG with emphasis on cloud discharge activity

    NASA Astrophysics Data System (ADS)

    Zhu, Y.; Rakov, V. A.; Tran, M. D.; Nag, A.

    2016-12-01

    The U.S. National Lightning Detection Network (NLDN) detection efficiency (DE) and classification accuracy (CA) for cloud discharge (IC) activity (identified here by a sequence of non-return-stroke-type electric field pulses not accompanied by channels to ground) were evaluated using optical and electric field data acquired at the LOG (Lightning Observatory in Gainesville), Florida. Our ground truth "IC events" include 26 "isolated IC events" (complete IC flashes), 58 "IC events before first return stroke," and 69 "IC events after first return stroke." For the total of 153 IC events, 33% were detected by the NLDN, and the classification accuracy was 86%. For complete IC flashes, the detection efficiency and classification accuracy were 73% and 95%, respectively, and the average number of NLDN-reported cloud pulses was 2.9 per detected event. For 24 preliminary breakdown pulse trains in CG flashes, the detection efficiency and classification accuracy were 46% and 82%, respectively. We have additionally estimated the DE and CA for return strokes in CG flashes. Irrespective of stroke order and polarity, the DE was 92% (339/367), and the CA was also 92% (312/339). The DEs for negative first and subsequent strokes were 98% and 90%, respectively.

  11. Are nematode collections in danger of extinction?

    PubMed

    Hockland, S; Hoestra, H

    2003-01-01

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

  12. Nematode.net: a tool for navigating sequences from parasitic and free-living nematodes

    PubMed Central

    Wylie, Todd; Martin, John C.; Dante, Michael; Mitreva, Makedonka Dautova; Clifton, Sandra W.; Chinwalla, Asif; Waterston, Robert H.; Wilson, Richard K.; McCarter, James P.

    2004-01-01

    Nematode.net (www.nematode.net) is a web- accessible resource for investigating gene sequences from nematode genomes. The database is an outgrowth of the parasitic nematode EST project at Washington University’s Genome Sequencing Center (GSC), St Louis. A sister project at the University of Edinburgh and the Sanger Institute is also underway. More than 295 000 ESTs have been generated from >30 nematodes other than Caenorhabditis elegans including key parasites of humans, animals and plants. Nematode.net currently provides NemaGene EST cluster consensus sequence, enhanced online BLAST search tools, functional classifications of cluster sequences and comprehensive information concerning the ongoing generation of nematode genome data. The long-term goal of nematode.net is to provide the scientific community with the highest quality sequence information and tools for studying these diverse species. PMID:14681448

  13. Detection of plant-parasitic nematode DNA in the gut of predatory and omnivorous nematodes

    USDA-ARS?s Scientific Manuscript database

    A protocol for molecular gut analysis of nematodes was developed to determine if predatory and omnivorous nematodes from five different guilds prey on Rotylenchulus reniformis, Meloidogyne incognita, and Radopholus similis. Mononchoides, Mononchus, Neoactinolaimus, Mesodorylaimus, and Aporcelaimell...

  14. Effect of Pneumococcal Conjugate Vaccine on the Natural Antibodies and Antibody Responses Against Protein Antigens From Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis in Children With Community-acquired Pneumonia.

    PubMed

    Andrade, Dafne C; Borges, Igor C; Adrian, Peter V; Meinke, Andreas; Barral, Aldina; Ruuskanen, Olli; Käyhty, Helena; Nascimento-Carvalho, Cristiana M

    2016-06-01

    Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are common causative agents of respiratory infections. Pneumococcal conjugate vaccines have been introduced recently, but their effect on the natural immunity against protein antigens from these pathogens has not been elucidated. This was an age-matched observational controlled study that evaluated the influence of 10-valent pneumococcal conjugate vaccines on the levels of antibodies and frequencies of antibody responses against proteins from S. pneumoniae, H. influenzae and M. catarrhalis in serum samples of children with community-acquired pneumonia. Eight pneumococcal proteins (pneumolysin, choline-binding protein A, pneumococcal surface protein A families 1 and 2, pneumococcal choline-binding protein A, pneumococcal histidine triad protein D, serine/threonine protein kinase, protein required for cell wall separation of group B streptococcus), 3 proteins from H. influenzae (including protein D) and 5 M. catarrhalis proteins were investigated. The study group comprised 38 vaccinated children and 114 age-matched controls (median age: 14.5 vs. 14.6 months, respectively; P = 0.997), all with community-acquired pneumonia. There was no difference on clinical baseline characteristics between vaccinated and unvaccinated children. Vaccinated children had significantly lower levels of antibodies against 4 of the studied pneumococcal antigens (P = 0.048 for Ply, P = 0.018 for pneumococcal surface protein A, P = 0.001 for StkP and P = 0.028 for PcsB) and higher levels of antibodies against M. catarrhalis (P = 0.015). Nevertheless, the vaccination status did not significantly affect the rates of antibody responses against S. pneumoniae, H. influenzae and M. catarrhalis. In spite of the differences that have been found on the level of natural antibodies, no effect from pneumococcal vaccination was observed on the rate of immune responses associated with community-acquired pneumonia against protein

  15. Plant and soil nematodes: societal impact and focus for the future.

    PubMed

    Barker, K R; Hussey, R S; Krusberg, L R; Bird, G W; Dunn, R A; Ferris, H; Ferris, V R; Freckman, D W; Gabriel, C J; Grewal, P S; Macguidwin, A E; Riddle, D L; Roberts, P A; Schmitt, D P

    1994-06-01

    Plant and soil nematodes significandy impact our lives. Therefore, we must understand and manage these complex organisms so that we may continue to develop and sustain our food production systems, our natural resources, our environment, and our quality of life. This publication looks specifically at soil and plant nematology. First, the societal impact of nematodes and benefits of nematology research are briefly presented. Next, the opportunities facing nematology in the next decade are outlined, as well as the resources needed to address these priorities. The safety and sustainability of U.S. food and fiber production depends on public and administrative understanding of the importance of nematodes, the drastic effects of nematodes on many agricultural and horticultural crops, and the current research priorities of nematology.

  16. Plant and Soil Nematodes: Societal Impact and Focus for the Future.

    PubMed Central

    Barker, K. R.; Hussey, R. S.; Krusberg, L. R.; Bird, G. W.; Dunn, R. A.; Ferris, H.; Ferris, V. R.; Freckman, D. W.; Gabriel, C. J.; Grewal, P. S.; MacGuidwin, A. E.; Riddle, D. L.; Roberts, P. A.; Schmitt, D. P.

    1994-01-01

    Plant and soil nematodes significandy impact our lives. Therefore, we must understand and manage these complex organisms so that we may continue to develop and sustain our food production systems, our natural resources, our environment, and our quality of life. This publication looks specifically at soil and plant nematology. First, the societal impact of nematodes and benefits of nematology research are briefly presented. Next, the opportunities facing nematology in the next decade are outlined, as well as the resources needed to address these priorities. The safety and sustainability of U.S. food and fiber production depends on public and administrative understanding of the importance of nematodes, the drastic effects of nematodes on many agricultural and horticultural crops, and the current research priorities of nematology. PMID:19279875

  17. Trichinella spiralis: genomic application to control a zoonotic nematode.

    PubMed

    Mitreva, Makedonka; Jasmer, Douglas P

    2010-10-01

    The nematode Trichinella spiralis and related species are zoonotic food-borne pathogens of humans. The muscle larval stage of this parasite establishes a chronic infection in skeletal muscle cells of humans who acquire trichinellosis. Muscle larvae also reside in skeletal muscles of animals, swine in particular, and other food animals, including game animals. These muscle larvae are the source of zoonotic transmission to humans. Once established, muscle larvae become less susceptible to anthelmintics that are effective against other stages of the parasite. Very little information exists to guide discovery of new drug targets and improved methods of eliminating muscle larvae established in muscle cells of humans or food animals. Here we discuss progress that has been made on sequencing the genome of T. spiralis. This informational resource should prove valuable for dissecting molecular characteristics of this parasite that warrant investigation as targets for chemotherapy. The availability of the T. spiralis genome has made possible the comparison of genomes from nematodes that span the evolutionary extremes of the phylum Nematoda. We describe a pan-phylum comparison of genomes that is underway. This comparative genomics approach is expected to identify molecular characteristics that are conserved among all nematodes, and hence applicable to nematode pathogens throughout the phylum, including species from the genus Trichinella. T. spiralis expression data for muscle larvae has been integrated with genome sequences to identify specific genes and proteins with relevance to control of this stage of the parasite. Examples are discussed in which genomic information may advance understanding of T. spiralis biology and new methods for treating infections by this parasite.

  18. Association of quantitative interferon-γ responses with the progression of naturally acquired Mycobacterium bovis infection in wild European badgers (Meles meles).

    PubMed

    Tomlinson, Alexandra J; Chambers, Mark A; McDonald, Robbie A; Delahay, Richard J

    2015-02-01

    Bovine tuberculosis is one of the biggest challenges facing cattle farming in Great Britain. European badgers (Meles meles) are a reservoir host for the causal agent, Mycobacterium bovis. There have been significant recent advances in diagnostic testing for tuberculosis in humans, cattle and badgers, with the development of species-specific assays for interferon-γ (IFN-γ), an important cytokine in tuberculous infections. Using data collected from longitudinal studies of naturally infected wild badgers, we report that the magnitude of the IFN-γ response to M. bovis antigens at the disclosing test event was positively correlated with subsequent progression of disease to a seropositive or excreting state. In addition, we show that the magnitude of the IFN-γ response, despite fluctuation, declined with time after the disclosing event for all badgers, but remained significantly higher in those animals with evidence of disease progression. We discuss how our findings may be related to the immunopathogenesis of natural M. bovis infection in badgers.

  19. Applying antibiotic selection markers for nematode genetics.

    PubMed

    Cornes, Eric; Quéré, Cécile A L; Giordano-Santini, Rosina; Dupuy, Denis

    2014-08-01

    Antibiotic selection markers have been recently developed in the multicellular model organism Caenorhabditis elegans and other related nematode species, opening great opportunities in the field of nematode transgenesis. Here we describe how these antibiotic selection systems can be easily combined with many well-established genetic approaches to study gene function, improving time- and cost-effectiveness of the nematode genetic toolbox. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Survey of Nematodes on Coffee in Hawaii

    PubMed Central

    Schenck, S.; Schmitt, D. P.

    1992-01-01

    Surveys of coffee fields in Hawaii during 1989-1991 indicated the presence of 10 nematode species in 8 genera. After coffee was planted in fields previously in sugarcane, populations of Criconemella sp. and Pratylenchus zeae gradually decreased, while Rotylenchulus reniformis and, in one field, Meloidogyne incognita, increased in numbers. Coffee is a poor host of R. reniformis, but weeds in coffee plantations may support this nematode. At present, nematodes pose no serious threat to Hawaii's expanding coffee industry. PMID:19283060

  1. Ecology and evolution of soil nematode chemotaxis.

    PubMed

    Rasmann, Sergio; Ali, Jared Gregory; Helder, Johannes; van der Putten, Wim H

    2012-06-01

    Plants influence the behavior of and modify community composition of soil-dwelling organisms through the exudation of organic molecules. Given the chemical complexity of the soil matrix, soil-dwelling organisms have evolved the ability to detect and respond to these cues for successful foraging. A key question is how specific these responses are and how they may evolve. Here, we review and discuss the ecology and evolution of chemotaxis of soil nematodes. Soil nematodes are a group of diverse functional and taxonomic types, which may reveal a variety of responses. We predicted that nematodes of different feeding guilds use host-specific cues for chemotaxis. However, the examination of a comprehensive nematode phylogeny revealed that distantly related nematodes, and nematodes from different feeding guilds, can exploit the same signals for positive orientation. Carbon dioxide (CO(2)), which is ubiquitous in soil and indicates biological activity, is widely used as such a cue. The use of the same signals by a variety of species and species groups suggests that parts of the chemo-sensory machinery have remained highly conserved during the radiation of nematodes. However, besides CO(2), many other chemical compounds, belonging to different chemical classes, have been shown to induce chemotaxis in nematodes. Plants surrounded by a complex nematode community, including beneficial entomopathogenic nematodes, plant-parasitic nematodes, as well as microbial feeders, are thus under diffuse selection for producing specific molecules in the rhizosphere that maximize their fitness. However, it is largely unknown how selection may operate and how belowground signaling may evolve. Given the paucity of data for certain groups of nematodes, future work is needed to better understand the evolutionary mechanisms of communication between plant roots and soil biota.

  2. Selective Serotonin Reuptake Inhibitor and Substance P Antagonist Enhancement of Natural Killer Cell Innate Immunity in Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome

    PubMed Central

    Evans, Dwight L.; Lynch, Kevin G.; Benton, Tami; Dubé, Benoit; Gettes, David R.; Tustin, Nancy B.; Lai, Jian Ping; Metzger, David; Douglas, Steven D.

    2010-01-01

    Background Natural killer (NK) cells play an important role in innate immunity and are involved in the host defense against human immunodeficiency virus (HIV) infection. This study examines the potential role of three underlying regulatory systems that have been under investigation in central nervous system research as well as immune and viral research: serotonin, neurokinin, and glucocorticoid systems. Methods Fifty-one HIV-seropositive subjects were recruited to achieve a representative sample of depressed and nondepressed women. The effects of a selective serotonin reuptake inhibitor (SSRI), a substance P (SP) antagonist, and a glucocorticoid antagonist on NK cell function were assessed in a series of ex vivo experiments of peripheral blood mononuclear cells from each HIV-seropositive subject. Results Natural killer cell cytolytic activity was significantly increased by the SSRI citalopram and by the substance P antagonist CP-96345 relative to control conditions; the glucocorticoid antagonist, RU486, showed no effect on NK cytotoxicity. Our results suggest that the effects of the three agents did not differ as a function of depression. Conclusions Our findings provide evidence that NK cell function in HIV infection may be enhanced by serotonin reuptake inhibition and by substance P antagonism. It remains to be determined if HIV-related impairment in not only NK cytolytic activity but also NK noncytolytic activity can be improved by an SSRI or an SP antagonist. Clinical studies are warranted to address these questions and the potential roles of serotonergic agents and SP antagonists in improving NK cell immunity, delaying HIV disease progression, and extending survival with HIV infection. PMID:17945197

  3. A Large Collection of Novel Nematode-Infecting Microsporidia and Their Diverse Interactions with Caenorhabditis elegans and Other Related Nematodes

    PubMed Central

    Zhang, Gaotian; Sachse, Martin; Prevost, Marie-Christine; Troemel, Emily R.; Félix, Marie-Anne

    2016-01-01

    Microsporidia are fungi-related intracellular pathogens that may infect virtually all animals, but are poorly understood. The nematode Caenorhabditis elegans has recently become a model host for studying microsporidia through the identification of its natural microsporidian pathogen Nematocida parisii. However, it was unclear how widespread and diverse microsporidia infections are in C. elegans or other related nematodes in the wild. Here we describe the isolation and culture of 47 nematodes with microsporidian infections. N. parisii is found to be the most common microsporidia infecting C. elegans in the wild. In addition, we further describe and name six new species in the Nematocida genus. Our sampling and phylogenetic analysis further identify two subclades that are genetically distinct from Nematocida, and we name them Enteropsectra and Pancytospora. Interestingly, unlike Nematocida, these two genera belong to the main clade of microsporidia that includes human pathogens. All of these microsporidia are horizontally transmitted and most specifically infect intestinal cells, except Pancytospora epiphaga that replicates mostly in the epidermis of its Caenorhabditis host. At the subcellular level in the infected host cell, spores of the novel genus Enteropsectra show a characteristic apical distribution and exit via budding off of the plasma membrane, instead of exiting via exocytosis as spores of Nematocida. Host specificity is broad for some microsporidia, narrow for others: indeed, some microsporidia can infect Oscheius tipulae but not its sister species Oscheius sp. 3, and conversely some microsporidia found infecting Oscheius sp. 3 do not infect O. tipulae. We also show that N. ausubeli fails to strongly induce in C. elegans the transcription of genes that are induced by other Nematocida species, suggesting it has evolved mechanisms to prevent induction of this host response. Altogether, these newly isolated species illustrate the diversity and ubiquity of

  4. Management of the Citrus Nematode, Tylenchulus semipenetrans

    PubMed Central

    Verdejo-Lucas, S.; McKenry, M. V.

    2004-01-01

    Of the many nematode species that parasitize citrus, Tylenchulus semipenetrans is the most important on a worldwide basis. Management of the citrus nematode remains problematic as no one tactic gives adequate control of the nematode. An overall management strategy must include such components as site selection, use of non-infected nursery stock, use of at lease one post-plant nematode control tactic, and careful management of other elements of the environment that may stress the trees. Nematicides continue to play a key role in management of this pest. Optimum results require careful attention to application techniques. PMID:19262822

  5. Eprinomectin pour-on (EPRINEX® Pour-on, Merial): efficacy against gastrointestinal and pulmonary nematodes and pharmacokinetics in sheep.

    PubMed

    Hamel, Dietmar; Bosco, Antonio; Rinaldi, Laura; Cringoli, Giuseppe; Kaulfuß, Karl-Heinz; Kellermann, Michael; Fischer, James; Wang, Hailun; Kley, Katrin; Mayr, Sandra; Rauh, Renate; Visser, Martin; Wiefel, Thea; Fankhauser, Becky; Rehbein, Steffen

    2017-05-30

    The anthelmintic efficacy of the 0.5% w/v topical formulation of eprinomectin (EPN), EPRINEX® Pour-on (Merial) when administered at 1 mg/kg body weight was evaluated in sheep in two dose confirmation laboratory studies and one multicenter field study. In addition, the pharmacokinetics of EPN when administered at that dosage to adult sheep was determined. In the two dose confirmation studies, which included 10 sheep each, sheep treated with topical EPN had significantly (p < 0.05) fewer of the following nematodes than the untreated sheep with overall reduction of nematode counts by >99%: adult Dictyocaulus filaria, Haemonchus contortus, Teladorsagia circumcincta(pinnata/trifurcata), Trichostrongylus axei, T. colubriformis, T. vitrinus, Cooperia curticei, Nematodirus battus, Strongyloides papillosus, Chabertia ovina and Oesophagostomum venulosum, and inhibited fourth-stage Teladorsagia larvae. A total of 196 sheep harboring naturally acquired gastrointestinal nematode infections were included in the field efficacy study at two sites each in Germany (48 Merino x Ile de France lambs, 52 adult Merino females) and in Italy (adult male and female Bagnolese, Lacaune, Lacaune x Bagnolese, Bagnolese x Sarda sheep; 48 animals per site). Animals were blocked on pre-treatment body weight and within each block, one animal was randomly assigned to the control (untreated) group and three animals were randomly assigned to be treated with topical EPN. Examination of feces 14 days after treatment demonstrated that, relative to the controls, topical EPN-treated sheep had significantly (p < 0.0001) lower strongylid egg counts. Reduction was ≥97% at each site and 98.6% across all sites. Pharmacokinetics of EPN following single treatment with topical EPN were determined in eight ~4.5 year old female Merino cross sheep based on the analysis of plasma samples which were collected from two hours to 21 days following treatment. The main pharmacokinetic parameters were: Cmax 6.20

  6. Distribution and molecular characterization of Wolbachia endosymbionts and filarial nematodes in Maryland populations of the lone star tick (Amblyomma americanum).

    PubMed

    Zhang, Xing; Norris, Douglas E; Rasgon, Jason L

    2011-07-01

    The lone star tick Amblyomma americanum is host to a wide diversity of endosymbiotic bacteria. We identified a novel Wolbachia symbiont infecting A. americanum. Multilocus sequence typing phylogenetically placed the endosymbiont in the increasingly diverse F supergroup. We assayed a total of 1031 ticks (119 females, 78 males and 834 nymphs in 89 pools) from 16 Maryland populations for infection. Infection frequencies in the natural populations were approximately 5% in females and <2% (minimum infection rate) in nymphs; infection was not detected in males. Infected populations were only observed in southern Maryland, suggesting the possibility that Wolbachia is currently invading Maryland A. americanum populations. Because F supergroup Wolbachia have been detected previously in filarial nematodes, tick samples were assayed for nematodes by PCR. Filarial nematodes were detected in 70% and 9% of Wolbachia-positive and Wolbachia-negative tick samples, respectively. While nematodes were more common in Wolbachia-positive tick samples, the lack of a strict infection concordance (Wolbachia-positive, nematode-negative and Wolbachia-negative, nematode-positive ticks) suggests that Wolbachia prevalence in ticks is not due to nematode infection. Supporting this hypothesis, phylogenetic analysis indicated that the nematodes were likely a novel species within the genus Acanthocheilonema, which has been previously shown to be Wolbachia-free. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  7. A Study of Naturally Acquired Canine Babesiosis Caused by Single and Mixed Babesia Species in Zambia: Clinicopathological Findings and Case Management

    PubMed Central

    Nalubamba, King Shimumbo; Mudenda, Ntombi Basimbi; Namwila, Mwaka Mwangala; Mulenga, Chilufya Susan; Bwalya, Eugene Chisela; M'kandawire, Ethel; Saasa, Ngonda; Hankanga, Careen; Oparaocha, Elizabeth; Simuunza, Martin

    2015-01-01

    A retrospective and prospective analysis of clinical records of dogs diagnosed with Babesia infections was carried out for the years 2000 to 2013 from practices in Lusaka, Zambia. Records of 363 dogs with confirmed Babesia infections were analysed using demographic factors including sex, breed, age, and clinical signs in relation to haematological findings and Babesia species. The clinical and laboratory findings observed are described as well as Babesia species identification. The study included 18 breeds and the highest proportion were mongrels (32.2%), males representing 64.5% of the population. The most common presenting problems were anorexia (65.3%) and lethargy/weakness (65.3%). The most common clinical signs were fever (87.3%), pallor (52.3%), lymphadenopathy (47.4%), and presence of ticks (44.9%). Anaemia (96.4%) and nucleated erythrocytes (42.2%) were the most common laboratory findings. A mixed infection of Babesia rossi and Babesia gibsoni was present in 59.7% of dogs, whilst 8% and 32.2% had B. rossi and B. gibsoni as a single infection, respectively. Case management mainly involved therapy with tetracyclines and imidocarb and was usually accompanied by clinical improvement. This study highlights, for the first time, the presence of B. gibsoni in natural dog populations in Zambia, where previously only B. rossi was reported. PMID:26682062

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

    NASA Astrophysics Data System (ADS)

    Moens, T.; Vincx, M.

    1998-06-01

    Although a large body of literature exists on the systematics and ecology of free-living marine and brackish-water nematodes, key questions on the nature and magnitude of interactions between nematodes and other organisms in the benthos remain unanswered. Relatively few authors have investigated live nematodes in food web studies or in experiments dealing with the nematodes’ response to a varying environment. It is mainly for the latter purpose that attempts have been made to maintain, rear and cultivate selected species. This paper describes the methodology used for the maintenance, rearing, and eventual permanent agnotobiotic cultivation of a variety of estuarine nematodes. Spot plates, where small samples of sediment or macrophyte material are inoculated on a sloppy agar layer, have been used for the purpose of maintenance and initial cultivation. Those species that reproduce on spot plates are then selected for monospecific cultivation on agar layers with different nutrient enrichments and with micro-organisms cotransferred from the spot plates as food. Mixtures of bacto and nutrient agar prepared in artificial seawater were specifically suitable for the xenic cultivation of nine bacterivorous and, when supplied with Erdschreiber nutrients, two algivorous/bacterivorous nematode species. Up to three generations of five other nematode species have been reared under laboratory conditions, and several more were kept alive and active for variable periods of time on agar. Generation times observed on spot plates for Adoncholaimus fuscus and Oncholaimus oxyuris were substantially shorter than previously published estimates and suggest a correspondingly higher predatory and scavenging potency for these and related enoplids. A procedure for the long-term storage of nematodes at -80°C with glycerol as a cryoprotectant was successfully used for Diplolaimella dievengatensis, Panagrolaimus sp. 1, and Pellioditis marina, but not for Diplolaimelloides meyli. The authors

  9. Evaluation of an in-house TgSAG1 (P30) IgG ELISA for diagnosis of naturally acquired Toxoplasma gondii infection in pigs.

    PubMed

    Pardini, L; Maksimov, P; Herrmann, D C; Bacigalupe, D; Rambeaud, M; Machuca, M; Moré, G; Basso, W; Schares, G; Venturini, M C

    2012-10-26

    Toxoplasma gondii is an apicomplexan protozoan parasite which is able to infect a large variety of warm-blooded animals. Raw or undercooked pork has been regarded as an important source of infection for humans. The aim of this study was to evaluate an in-house enzyme-linked immunosorbent assay to diagnose natural T. gondii infection in swine using native affinity chromatography-purified T. gondii surface protein-1 (TgSAG1-ELISA) as antigen, comparing its performance to that of indirect fluorescent antibody test (IFAT) and immunoblotting (IB). To obtain a panel of sera showing the evolution of the antibody response in the time course 12 pigs were experimentally inoculated intravenously (iv) with tachyzoites of the T. gondii strains RH (clonal type I), ME49 (clonal type II) and NED (clonal type III) and serologically monitored for a period of 11 weeks. Both IFAT and ELISA showed a similar time course of antibody response to T. gondii; but by IFAT this response was characterized by rapidly rising titers with peaks at two weeks post inoculation (wpi), while the ELISA indices increased slowly and reached a maximum in most animals at five wpi. Three-hundred randomly selected sera from a total of 602 pigs of different ages derived from outdoor and indoor farms from Argentina were analyzed. Serum samples testing either positive or negative by both IFAT and IB were considered as "relative standards of comparison" (RSC). Sensitivity and specificity of TgSAG1-ELISA were obtained by a Receiver Operating Characteristics (ROC) analysis and statistical agreement among serological tests was evaluated. Antibodies to T. gondii were detected in 160 of 300 sera (53.3%) by IB, in 133 of 300 (44.3%) by IFAT and in 123 of 300 sera (41%) by TgSAG1-ELISA. One hundred and eleven sera tested positive and 118 sera tested negative by both IFAT and IB (RSC); 103 of 111 positive RSC sera tested positive by TgSAG1-ELISA, and 116 of 118 negative RSC sera tested negative by TgSAG1-ELISA. Agreement

  10. Plasmodium vivax VIR Proteins Are Targets of Naturally-Acquired Antibody and T Cell Immune Responses to Malaria in Pregnant Women

    PubMed Central

    Requena, Pilar; Rui, Edmilson; Padilla, Norma; Martínez-Espinosa, Flor E.; Castellanos, Maria Eugenia; Bôtto-Menezes, Camila; Malheiro, Adriana; Arévalo-Herrera, Myriam; Kochar, Swati; Kochar, Sanjay K.; Kochar, Dhanpat K.; Umbers, Alexandra J.; Ome-Kaius, Maria; Wangnapi, Regina; Hans, Dhiraj; Menegon, Michela; Mateo, Francesca; Sanz, Sergi; Desai, Meghna; Mayor, Alfredo; Chitnis, Chetan C.; Bardají, Azucena; Mueller, Ivo; Rogerson, Stephen; Severini, Carlo; Fernández-Becerra, Carmen; Menéndez, Clara

    2016-01-01

    P. vivax infection during pregnancy has been associated with poor outcomes such as anemia, low birth weight and congenital malaria, thus representing an important global health problem. However, no vaccine is currently available for its prevention. Vir genes were the first putative virulent factors associated with P. vivax infections, yet very few studies have examined their potential role as targets of immunity. We investigated the immunogenic properties of five VIR proteins and two long synthetic peptides containing conserved VIR sequences (PvLP1 and PvLP2) in the context of the PregVax cohort study including women from five malaria endemic countries: Brazil, Colombia, Guatemala, India and Papua New Guinea (PNG) at different timepoints during and after pregnancy. Antibody responses against all antigens were detected in all populations, with PNG women presenting the highest levels overall. P. vivax infection at sample collection time was positively associated with antibody levels against PvLP1 (fold-increase: 1.60 at recruitment -first antenatal visit-) and PvLP2 (fold-increase: 1.63 at delivery), and P. falciparum co-infection was found to increase those responses (for PvLP1 at recruitment, fold-increase: 2.25). Levels of IgG against two VIR proteins at delivery were associated with higher birth weight (27 g increase per duplicating antibody levels, p<0.05). Peripheral blood mononuclear cells from PNG uninfected pregnant women had significantly higher antigen-specific IFN-γ TH1 responses (p=0.006) and secreted less pro-inflammatory cytokines TNF and IL-6 after PvLP2 stimulation than P. vivax-infected women (p<0.05). These data demonstrate that VIR antigens induce the natural acquisition of antibody and T cell memory responses that might be important in immunity to P. vivax during pregnancy in very diverse geographical settings. PMID:27711158

  11. Plasmodium vivax VIR Proteins Are Targets of Naturally-Acquired Antibody and T Cell Immune Responses to Malaria in Pregnant Women.

    PubMed

    Requena, Pilar; Rui, Edmilson; Padilla, Norma; Martínez-Espinosa, Flor E; Castellanos, Maria Eugenia; Bôtto-Menezes, Camila; Malheiro, Adriana; Arévalo-Herrera, Myriam; Kochar, Swati; Kochar, Sanjay K; Kochar, Dhanpat K; Umbers, Alexandra J; Ome-Kaius, Maria; Wangnapi, Regina; Hans, Dhiraj; Menegon, Michela; Mateo, Francesca; Sanz, Sergi; Desai, Meghna; Mayor, Alfredo; Chitnis, Chetan C; Bardají, Azucena; Mueller, Ivo; Rogerson, Stephen; Severini, Carlo; Fernández-Becerra, Carmen; Menéndez, Clara; Del Portillo, Hernando; Dobaño, Carlota

    2016-10-01

    P. vivax infection during pregnancy has been associated with poor outcomes such as anemia, low birth weight and congenital malaria, thus representing an important global health problem. However, no vaccine is currently available for its prevention. Vir genes were the first putative virulent factors associated with P. vivax infections, yet very few studies have examined their potential role as targets of immunity. We investigated the immunogenic properties of five VIR proteins and two long synthetic peptides containing conserved VIR sequences (PvLP1 and PvLP2) in the context of the PregVax cohort study including women from five malaria endemic countries: Brazil, Colombia, Guatemala, India and Papua New Guinea (PNG) at different timepoints during and after pregnancy. Antibody responses against all antigens were detected in all populations, with PNG women presenting the highest levels overall. P. vivax infection at sample collection time was positively associated with antibody levels against PvLP1 (fold-increase: 1.60 at recruitment -first antenatal visit-) and PvLP2 (fold-increase: 1.63 at delivery), and P. falciparum co-infection was found to increase those responses (for PvLP1 at recruitment, fold-increase: 2.25). Levels of IgG against two VIR proteins at delivery were associated with higher birth weight (27 g increase per duplicating antibody levels, p<0.05). Peripheral blood mononuclear cells from PNG uninfected pregnant women had significantly higher antigen-specific IFN-γ TH1 responses (p=0.006) and secreted less pro-inflammatory cytokines TNF and IL-6 after PvLP2 stimulation than P. vivax-infected women (p<0.05). These data demonstrate that VIR antigens induce the natural acquisition of antibody and T cell memory responses that might be important in immunity to P. vivax during pregnancy in very diverse geographical settings.

  12. Human mesenchymal stromal/stem cells acquire immunostimulatory capacity upon cross-talk with natural killer cells and might improve the NK cell function of immunocompromised patients.

    PubMed

    Cui, Rongtao; Rekasi, Heike; Hepner-Schefczyk, Monika; Fessmann, Kai; Petri, Robert M; Bruderek, Kirsten; Brandau, Sven; Jäger, Marcus; Flohé, Stefanie B

    2016-07-07

    The suppressive effect of mesenchymal stromal/stem cells (MSCs) on diverse immune cells is well known, but it is unclear whether MSCs additionally possess immunostimulatory properties. We investigated the impact of human MSCs on the responsiveness of primary natural killer (NK) cells in terms of cytokine secretion. Human MSCs were generated from bone marrow and nasal mucosa. NK cells were isolated from peripheral blood of healthy volunteers or of immunocompromised patients after severe injury. NK cells were cultured with MSCs or with MSC-derived conditioned media in the absence or presence of IL-12 and IL-18. C-C chemokine receptor (CCR) 2, C-C chemokine ligand (CCL) 2, and the interferon (IFN)-γ receptor was blocked by specific inhibitors or antibodies. The synthesis of IFN-γ and CCL2 was determined. In the absence of exogenous cytokines, trace amounts of NK cell-derived IFN-γ licensed MSCs for enhanced synthesis of CCL2. In turn, MSCs primed NK cells for increased release of IFN-γ in response to IL-12 and IL-18. Priming of NK cells by MSCs occurred in a cell-cell contact-independent manner and was impaired by inhibition of the CCR2, the receptor of CCL2, on NK cells. CD56(bright) NK cells expressed higher levels of CCR2 and were more sensitive to CCL2-mediated priming by MSCs and by recombinant CCR2 ligands than cytotoxic CD56(dim) NK cells. NK cells from severely injured patients were impaired in cytokine-induced IFN-γ synthesis. Co-culture with MSCs or with conditioned media from MSCs and MSC/NK cell co-cultures from healthy donors improved the IFN-γ production of the patients' NK cells in a CCR2-dependent manner. A positive feedback loop driven by NK cell-derived IFN-γ and MSC-derived CCL2 increases the inflammatory response of cytokine-stimulated NK cells not only from healthy donors but also from immunocompromised patients. Therapeutic application of MSCs or their soluble factors might thus improve the NK function after severe injury.

  13. Comparing systemic defence-related gene expression changes upon migratory and sedentary nematode attack in rice.

    PubMed

    Kyndt, T; Nahar, K; Haegeman, A; De Vleesschauwer, D; Höfte, M; Gheysen, G

    2012-03-01

    Complex defence signalling pathways, controlled by different hormones, are known to be involved in the reaction of plants to a wide range of biotic and abiotic stress factors. Here, we studied the differential expression of genes involved in stress and defence responses in systemic tissue of rice infected with the root knot nematode (RKN) Meloidogyne graminicola and the migratory root rot nematode Hirschmanniella oryzae, two agronomically important rice pathogens with very different lifestyles. qRT-PCR revealed that all investigated systemic tissues had significantly lower expression of isochorismate synthase, a key enzyme for salicylic acid production involved in basal defence and systemic acquired resistance. The systemic defence response upon migratory nematode infection was remarkably similar to fungal rice blast infection. Almost all investigated defence-related genes were up-regulated in rice shoots 3 days after root rot nematode attack, including the phenylpropanoid pathway, ethylene pathway and PR genes, but many of which were suppressed at 7 dpi. Systemic shoot tissue of RKN-infected plants showed similar attenuation of expression of almost all studied genes already at 3 dpi, with clear attenuation of the ethylene pathway and methyl jasmonate biosynthesis. These results provide an interesting starting point for further studies to elucidate how nematodes are able to suppress systemic plant defence mechanisms and the effect in multitrophic interactions.

  14. Agrobacteria Enhance Plant Defense Against Root-Knot Nematodes on Tomato.

    PubMed

    Lamovšek, Janja; Gerič Stare, Barbara; Mavrič Pleško, Irena; Širca, Saša; Urek, Gregor

    2017-01-30

    The increased incidence of the crown gall disease caused by Agrobacterium tumefaciens has long been associated with activities of root-knot nematodes, Meloidogyne spp. Pot experiments on tomato were designed to assess plant vitality, nematode reproduction and crown gall incidence in combined infection with Agrobacterium and Meloidogyne on tomato roots. Results suggest that tomato plants infected with pathogenic A. tumefaciens two days before the nematodes show enhanced plant defense against M. ethiopica resulting in lower egg and gall counts on roots 45 and 90 days post inoculation (dpi); no significantly enhanced defense was observed when the plant was inoculated with bacteria and nematodes at the same time. Split-root experiments also showed that the observed interaction was systemic. RT-qPCR analysis that targeted several genes under plant hormonal control suggests that the suppression was mediated via systemic acquired resistance by the pathogenesis-related protein 1 (PR1) and that M. ethiopica did not enhance the defense reaction of tomato against Agrobacterium. Nematodes completely inhibited tumor growth in a 45-day experiment if inoculated onto the roots before the pathogenic bacteria. We conclude that the observed antagonism in the tested pathosystem was the result of initially strong plant defense that was later suppressed by the invading pathogen and pest.

  15. Tm1: A Mutator/Foldback Transposable Element Family in Root-Knot Nematodes

    PubMed Central

    Gross, Stephen M.; Williamson, Valerie M.

    2011-01-01

    Three closely related parthenogenetic species of root-knot nematodes, collectively termed the Meloidogyne incognita-group, are economically significant pathogens of diverse crop species. Remarkably, these asexual root-knot nematodes are capable of acquiring heritable changes in virulence even though they lack sexual reproduction and meiotic recombination. Characterization of a near isogenic pair of M. javanica strains differing in response to tomato with the nematode resistance gene Mi-1 showed that the virulent strain carried a deletion spanning a gene called Cg-1. Herein, we present evidence that the Cg-1 gene lies within a member of a novel transposable element family (Tm1; Transposon in Meloidogyne-1). This element family is defined by composite terminal inverted repeats of variable lengths similar to those of Foldback (FB) transposable elements and by 9 bp target site duplications. In M. incognita, Tm1 elements can be classified into three general groups: 1) histone-hairpin motif elements; 2) MITE-like elements; 3) elements encoding a putative transposase. The predicted transposase shows highest similarity to gene products encoded by aphids and mosquitoes and resembles those of the Phantom subclass of the Mutator transposon superfamily. Interestingly, the meiotic, sexually-reproducing root-knot nematode species M. hapla has Tm1 elements with similar inverted repeat termini, but lacks elements with histone hairpin motifs and contains no elements encoding an intact transposase. These Tm1 elements may have impacts on root-knot nematode genomes and contribute to genetic diversity of the asexual species. PMID:21931741

  16. Tm1: a mutator/foldback transposable element family in root-knot nematodes.

    PubMed

    Gross, Stephen M; Williamson, Valerie M

    2011-01-01

    Three closely related parthenogenetic species of root-knot nematodes, collectively termed the Meloidogyne incognita-group, are economically significant pathogens of diverse crop species. Remarkably, these asexual root-knot nematodes are capable of acquiring heritable changes in virulence even though they lack sexual reproduction and meiotic recombination. Characterization of a near isogenic pair of M. javanica strains differing in response to tomato with the nematode resistance gene Mi-1 showed that the virulent strain carried a deletion spanning a gene called Cg-1. Herein, we present evidence that the Cg-1 gene lies within a member of a novel transposable element family (Tm1; Transposon in Meloidogyne-1). This element family is defined by composite terminal inverted repeats of variable lengths similar to those of Foldback (FB) transposable elements and by 9 bp target site duplications. In M. incognita, Tm1 elements can be classified into three general groups: 1) histone-hairpin motif elements; 2) MITE-like elements; 3) elements encoding a putative transposase. The predicted transposase shows highest similarity to gene products encoded by aphids and mosquitoes and resembles those of the Phantom subclass of the Mutator transposon superfamily. Interestingly, the meiotic, sexually-reproducing root-knot nematode species M. hapla has Tm1 elements with similar inverted repeat termini, but lacks elements with histone hairpin motifs and contains no elements encoding an intact transposase. These Tm1 elements may have impacts on root-knot nematode genomes and contribute to genetic diversity of the asexual species.

  17. NGT-3D: a simple nematode cultivation system to study Caenorhabditis elegans biology in 3D.

    PubMed

    Lee, Tong Young; Yoon, Kyoung-Hye; Lee, Jin Il

    2016-04-15

    The nematodeCaenorhabditiselegansis one of the premier experimental model organisms today. In the laboratory, they display characteristic development, fertility, and behaviors in a two dimensional habitat. In nature, however,C. elegansis found in three dimensional environments such as rotting fruit. To investigate the biology ofC. elegansin a 3D controlled environment we designed a nematode cultivation habitat which we term the nematode growth tube or NGT-3D. NGT-3D allows for the growth of both nematodes and the bacteria they consume. Worms show comparable rates of growth, reproduction and lifespan when bacterial colonies in the 3D matrix are abundant. However, when bacteria are sparse, growth and brood size fail to reach levels observed in standard 2D plates. Using NGT-3D we observe drastic deficits in fertility in a sensory mutant in 3D compared to 2D, and this defect was likely due to an inability to locate bacteria. Overall, NGT-3D will sharpen our understanding of nematode biology and allow scientists to investigate questions of nematode ecology and evolutionary fitness in the laboratory.

  18. Transgenic Potatoes for Potato Cyst Nematode Control Can Replace Pesticide Use without Impact on Soil Quality

    PubMed Central

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

    2012-01-01

    Current and future global crop yields depend upon soil quality to which soil organisms make an important contribution. The European Union seeks to protect European soils and their biodiversity for instance by amending its Directive on pesticide usage. This poses a challenge for control of Globodera pallida (a potato cyst nematode) for which both natural resistance and rotational control are inadequate. One approach of high potential is transgenically based resistance. This work demonstrates the potential in the field of a new transgenic trait for control of G. pallida that suppresses root invasion. It also investigates its impact and that of a second transgenic trait on the non-target soil nematode community. We establish that a peptide that disrupts chemoreception of nematodes without a lethal effect provides resistance to G. pallida in both a containment and a field trial when precisely targeted under control of a root tip-specific promoter. In addition we combine DNA barcoding and quantitative PCR to recognise nematode genera from soil samples without microscope-based observation and use the method for nematode faunal analysis. This approach establishes that the peptide and a cysteine proteinase inhibitor that offer distinct bases for transgenic plant resistance to G. pallida do so without impact on the non-target nematode soil community. PMID:22359559

  19. NGT-3D: a simple nematode cultivation system to study Caenorhabditis elegans biology in 3D

    PubMed Central

    Lee, Tong Young; Yoon, Kyoung-hye; Lee, Jin Il

    2016-01-01

    ABSTRACT The nematode Caenorhabditis elegans is one of the premier experimental model organisms today. In the laboratory, they display characteristic development, fertility, and behaviors in a two dimensional habitat. In nature, however, C. elegans is found in three dimensional environments such as rotting fruit. To investigate the biology of C. elegans in a 3D controlled environment we designed a nematode cultivation habitat which we term the nematode growth tube or NGT-3D. NGT-3D allows for the growth of both nematodes and the bacteria they consume. Worms show comparable rates of growth, reproduction and lifespan when bacterial colonies in the 3D matrix are abundant. However, when bacteria are sparse, growth and brood size fail to reach levels observed in standard 2D plates. Using NGT-3D we observe drastic deficits in fertility in a sensory mutant in 3D compared to 2D, and this defect was likely due to an inability to locate bacteria. Overall, NGT-3D will sharpen our understanding of nematode biology and allow scientists to investigate questions of nematode ecology and evolutionary fitness in the laboratory. PMID:26962047

  20. Transgenic potatoes for potato cyst nematode control can replace pesticide use without impact on soil quality.

    PubMed

    Green, Jayne; Wang, Dong; Lilley, Catherine J; Urwin, Peter E; Atkinson, Howard J

    2012-01-01

    Current and future global crop yields depend upon soil quality to which soil organisms make an important contribution. The European Union seeks to protect European soils and their biodiversity for instance by amending its Directive on pesticide usage. This poses a challenge for control of Globodera pallida (a potato cyst nematode) for which both natural resistance and rotational control are inadequate. One approach of high potential is transgenically based resistance. This work demonstrates the potential in the field of a new transgenic trait for control of G. pallida that suppresses root invasion. It also investigates its impact and that of a second transgenic trait on the non-target soil nematode community. We establish that a peptide that disrupts chemoreception of nematodes without a lethal effect provides resistance to G. pallida in both a containment and a field trial when precisely targeted under control of a root tip-specific promoter. In addition we combine DNA barcoding and quantitative PCR to recognise nematode genera from soil samples without microscope-based observation and use the method for nematode faunal analysis. This approach establishes that the peptide and a cysteine proteinase inhibitor that offer distinct bases for transgenic plant resistance to G. pallida do so without impact on the non-target nematode soil community.

  1. Biological Control of Nematodes with Bacteria

    USDA-ARS?s Scientific Manuscript database

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

  2. Endemic Oscheius Nematodes of Hawai'i

    USDA-ARS?s Scientific Manuscript database

    Entomopathogenic nematodes (EPNs) parasitize insects utilizing mutualistic bacteria to kill the host, allowing the nematode to feed and reproduce within the insect cadaver. Consequently EPNs are highly sought after for their biological control potential. A survey for EPNs was conducted on O’ahu and...

  3. Blends of ascarosides regulate dispersal in nematodes

    USDA-ARS?s Scientific Manuscript database

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

  4. Interspecific nematode signals regulate dispersal behavior

    USDA-ARS?s Scientific Manuscript database

    Dispersal is an important nematode behavior. Upon crowding or food depletion, the free living bacteriovorus nematode Caenorhabditis elegans produces stress resistant dispersal larvae, called dauer, which are analogous to second stage juveniles (J2) of plant parasitic Meloidogyne spp. and infective ...

  5. Imported Infections with Mansonella perstans Nematodes, Italy

    PubMed Central

    Beltrame, Anna; Buonfrate, Dora; Staffolani, Silvia; Degani, Monica; Gobbo, Maria; Angheben, Andrea; Marocco, Stefania; Bisoffi, Zeno

    2017-01-01

    We report 74 patients in Italy infected with Mansonella perstans nematodes, a poorly described filarial parasite. M. perstans nematodes should be included in the differential diagnosis for patients with eosinophilia from disease-endemic countries. Serologic analysis is useful for screening, and testing for microfilaremia in peripheral blood should be performed for parasite-positive patients. PMID:28820369

  6. Mechanisms of host seeking by parasitic nematodes.

    PubMed

    Gang, Spencer S; Hallem, Elissa A

    2016-07-01

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

  7. Nematodes ultrastructure: complex systems and processes.

    PubMed

    Basyoni, Maha M A; Rizk, Enas M A

    2016-12-01

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

  8. Improved nematode extraction from carrot disk culture.

    PubMed

    Kaplan, D T; Davis, E L

    1990-07-01

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

  9. Improved Nematode Extraction from Carrot Disk Culture

    PubMed Central

    Kaplan, David T.; Davis, Eric L.

    1990-01-01

    Radopholus spp. were reared in carrot tissue culture via established procedures, with slight modification. Several plant tissue maceration enzymes and flotation media (salts and sucrose) were evaluated with regard to nematode toxicity and extraction efficiency. Best extraction of viable nematodes and eggs was attained when carrot tissue infested with Radopholus citrophilus or R. similis was macerated with a mixture of 0.50% driselase and 0.50% cellulysin, w/v each, with 2.5 ml of enzyme solution based for each gram of carrot tissue. Maceration slurries containing carrot tissue and nematodes were maintained in open flasks on a rotary shaker (175 rpm) at 26 C for 24 hours. Nematodes and eggs were extracted from resultant culture slurries by flotation with MgSO₄-7H₂0 (sp gr 1.1). A protocol is presented to extract large quantities of viable burrowing nematodes and their eggs from carrot disk cultures. PMID:19287736

  10. Plant basal resistance to nematodes: an update.

    PubMed

    Holbein, Julia; Grundler, Florian M W; Siddique, Shahid

    2016-03-01

    Most plant-parasitic nematodes are obligate biotrophs feeding on the roots of their hosts. Whereas ectoparasites remain on the root surface and feed on the outer cell layers, endoparasitic nematodes enter the host to parasitize cells around or within the central cylinder. Nematode invasion and feeding causes tissue damage which may, in turn, lead to the activation of host basal defence responses. Hitherto, research interests in plant-nematode interaction have emphasized effector-triggered immunity rather than basal plant defence responses. However, some recent investigations suggest that basal defence pathways are not only activated but also play an important role in determining interaction outcomes. In this review we discuss the major findings and point out future directions to dissect the molecular mechanisms underlying plant basal defence to nematodes further. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  11. Efficacy against nematode infections and safety of afoxolaner plus milbemycin oxime chewable tablets in domestic dogs under field conditions in Europe.

    PubMed

    Rehbein, Steffen; Knaus, Martin; Mallouk, Yasmina; Breiltgens, Tatjana; Brianti, Emanuele; Capári, Balázs; Dantas-Torres, Filipe; Gau, Michel; Joachim, Anja; Kaulfuß, Karl-Heinz; Kirkova, Zvezdelina; Lechner, Joerg; Mihalca, Andrei D; Mirabito, Rosamaria; Petkevičius, Saulius; Rapti, Dhimitër; Shukullari, Enstela; Sedeilhan, Michel; Dollhofer, Doris; Kley, Katrin; Lebon, Wilfried; Visser, Martin; Jeannin, Philippe

    2017-01-01

    Afoxolaner (AFX) plus milbemycin oxime (MO) combination chewable tablets (NexGard Spectra®, Merial) were evaluated for safety and efficacy against naturally acquired nematode infections in domestic dogs in a multi-centre, positive control, blinded field study using a randomized block design based on the order of presentation for allocation. In total, 408 dogs confirmed positive for naturally acquired infections of intestinal nematodes by pre-treatment faecal examination were studied in ten countries in Europe (Albania, Austria, Bulgaria, France, Germany, Hungary, Italy, Lithuania, Romania and Slovakia). Pre-treatment faecal examination revealed Toxocara, Toxascaris, hookworm, Trichuris and/or Capillaria nematode infections in 134, 30, 223, 155 and 14 dogs, respectively. Dogs were allocated to one of two treatment groups in a ratio of 1, AFX + MO chewables (≥2.5 mg AFX + ≥0.5 mg MO per kg body weight, according to dose bands; 207 dogs), and 1, MO plus praziquantel (PRZ) chewables (Milbemax®, Novartis; ≥0.5 mg MO + ≥5 mg PRZ per kg body weight, according to the manufacturer's instructions; 201 dogs) and treated once. For evaluation of efficacy based on reduction of faecal nematode egg counts, two faecal samples, one collected prior to treatment and one collected 9 to 21 days after treatment, were examined using modified McMaster techniques. For evaluation of systemic safety, dogs were examined by a veterinarian before treatment administration and at study end, and dog owners observed the health status of their dogs until the end of the study and reported any abnormal observation. For dogs treated with AFX + MO chewables, the efficacy was 99.7, 99.7, 97.2, 99.7 and 99.7 % for Toxocara, Toxascaris, hookworm, Trichuris and Capillaria, respectively; and the efficacy was 99.5, 99.4, 94.3, 99.9 and 98.0 %, respectively, for the MO + PRZ-treated dogs (p ≤ 0.002 for all nematodes and both treatments). For Toxocara, hookworm and Trichuris, non

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

    PubMed

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

    2014-05-01

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

  13. Efficacy against nematode and cestode infections and safety of a novel topical fipronil, (S)-methoprene, eprinomectin and praziquantel combination product in domestic cats under field conditions in Europe.

    PubMed

    Rehbein, Steffen; Capári, Balazs; Duscher, Georg; Keidane, Dace; Kirkova, Zvezdelina; Petkevičius, Saulius; Rapti, Dhimiter; Wagner, Annegret; Wagner, Thomas; Chester, S Theodore; Rosentel, Joseph; Tielemans, Eric; Visser, Martin; Winter, Renate; Kley, Katrin; Knaus, Martin

    2014-04-28

    A novel topical combination product (BROADLINE(®), Merial) composed of fipronil, (S)-methoprene, eprinomectin and praziquantel was evaluated for safety and efficacy against nematode and cestode infections in domestic cats. The study comprised a multi-centre, positive control, blinded, field study, using a randomized block design based on order of presentation for allocation. In total 196 client-owned cats, confirmed as positive for naturally acquired infections of nematodes and/or cestodes by pre-treatment faecal examination, were studied in seven countries in Europe. Pre-treatment faecal examination revealed the presence of Toxocara, hookworm, Capillaria and/or spirurid nematode infections in 129, 73, 33 or 1 cat(s), respectively; infections with taeniid and Dipylidium cestodes were demonstrated in 39 and 17 cats, respectively. Cats were allocated randomly to one of two treatments in a ratio of 2, topical fipronil (8.3%, w/v), (S)-methoprene (10%, w/v), eprinomectin (0.4%, w/v) and praziquantel (8.3%, w/v) (BROADLINE(®), Merial; 130 cats); and 1, topical PROFENDER(®) Spot-On (Bayer; 66 cats) and treated once on Day 0. For evaluation of efficacy, two faecal samples were collected, one prior to treatment (Day -4 ± 4 days) and one at the end of the study (Day 14 ± 5 days). These were examined for fecal forms of nematode and cestode parasites. For evaluation of safety, cats were examined by a veterinarian before treatment and at the end of the study, and cat owners recorded the health status of their cats daily until the end of the study. For cats treated with Broadline(®), the efficacy was >99.9%, 100%, and 99.6% for Toxocara, hookworms, and Capillaria, respectively; and the efficacy was >99.9%, >99.9%, and 98.5%, respectively, for the cats treated with Profender(®) (p<0.001 for all nematodes and both treatments). Efficacy was 100% for both cestodes for both treatments (p<0.001). No treatment related adverse experiences were observed throughout the study. For

  14. Origins of Nematode Parasitism in the Families Strongyloididae, Rhabditidae, Plectidae and Diplogasteridae

    NASA Astrophysics Data System (ADS)

    Sachson, W.; Ngo, K.; Heim, N.; Payne, J.

    2016-12-01

    Parasitism is a fairly common trait found in the animal kingdom, and the effects parasites have on organisms is closely studied. On the other hand, how many different organisms evolve to become parasites is relatively unstudied, but trends between the size of these parasites and their environment may hold clues to their emergence. By looking at the size of parasitic nematodes, their free-living relatives and their environments, it is possible to deduce the cause of the parasitic tendencies of these families. In regard to nematodes, comparison of their body size and lifestyle does indeed reveal a trend between parasitic and free-living species. Many nematodes within the same family have evolved drastically different lifestyles within the same environment, and some have evolved when a new environment is available. In particular, the families Rhabditidae, Strongyloididae, Plectidae, and Diplogasteridae show abnormal ratios of parasite species to free-living species compared to others, in the case of Rhabditidae nearing a 1:1 ratio. Most importantly, the nature of each departure from each lifestyle appears to influence the size of the organism. What has been noticed in parasites can be described as an adaptation of Foster's Rule, which dictates the size of parasites depending on the environment and ecology of their ancestor. First of all, parasites change their size depending on their available resources. When free-living nematodes are given the opportunity to parasitize another organism, their body size changes in respect to the abundance of nutrients the nematode can extract from the host, which tends to let nematodes grow larger. On the other hand, when a parasitic nematode exits from parasitism to live freely or is parasitizing an organism within their natural environment, their size should decrease as they do not have access to as many resources as they did before. Using this idea, it is possible to understand the origins of parasitism and how organisms are driven

  15. Recruitment of entomopathogenic nematodes by insect-damaged maize roots.

    PubMed

    Rasmann, Sergio; Köllner, Tobias G; Degenhardt, Jörg; Hiltpold, Ivan; Toepfer, Stefan; Kuhlmann, Ulrich; Gershenzon, Jonathan; Turlings, Ted C J

    2005-04-07

    Plants under attack by arthropod herbivores often emit volatile compounds from their leaves that attract natural enemies of the herbivores. Here we report the first identification of an insect-induced belowground plant signal, (E)-beta-caryophyllene, which strongly attracts an entomopathogenic nematode. Maize roots release this sesquiterpene in response to feeding by larvae of the beetle Diabrotica virgifera virgifera, a maize pest that is currently invading Europe. Most North American maize lines do not release (E)-beta-caryophyllene, whereas European lines and the wild maize ancestor, teosinte, readily do so in response to D. v. virgifera attack. This difference was consistent with striking differences in the attractiveness of representative lines in the laboratory. Field experiments showed a fivefold higher nematode infection rate of D. v. virgifera larvae on a maize variety that produces the signal than on a variety that does not, whereas spiking the soil near the latter variety with authentic (E)-beta-caryophyllene decreased the emergence of adult D. v. virgifera to less than half. North American maize lines must have lost the signal during the breeding process. Development of new varieties that release the attractant in adequate amounts should help enhance the efficacy of nematodes as biological control agents against root pests like D. v. virgifera.

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

    PubMed

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

    2012-12-18

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

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

    PubMed Central

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

    2012-01-01

    Nematodes use an extensive chemical language based on glycosides of the dideoxysugar ascarylose for developmental regulation (dauer formation), male sex attraction, aggregation, and dispersal. However, no examples of a female- or hermaphrodite-specific sex attractant have been identified to date. In this study, we investigated the pheromone system of the gonochoristic sour paste nematode Panagrellus redivivus, which produces sex-specific attractants of the opposite sex. Activity-guided fractionation of the P. redivivus exometabolome revealed that males are strongly attracted to ascr#1 (also known as daumone), an ascaroside previously identified from Caenorhabditis elegans hermaphrodites. Female P. redivivus are repelled by high concentrations of ascr#1 but are specifically attracted to a previously unknown ascaroside that we named dhas#18, a dihydroxy derivative of the known ascr#18 and an ascaroside that features extensive functionalization of the lipid-derived side chain. Targeted profiling of the P. redivivus exometabolome revealed several additional ascarosides that did not induce strong chemotaxis. We show that P. redivivus females, but not males, produce the male-attracting ascr#1, whereas males, but not females, produce the female-attracting dhas#18. These results show that ascaroside biosynthesis in P. redivivus is highly sex-specific. Furthermore, the extensive side chain functionalization in dhas#18, which is reminiscent of polyketide-derived natural products, indicates unanticipated biosynthetic capabilities in nematodes. PMID:23213209

  18. Sex-specific lifespan and its evolution in nematodes.

    PubMed

    Ancell, Henry; Pires-daSilva, Andre

    2017-10-01

    Differences between sexes of the same species in lifespan and aging rate are widespread. While the proximal and evolutionary causes of aging are well researched, the factors that contribute to sex differences in these traits have been less studied. The striking diversity of nematodes provides ample opportunity to study variation in sex-specific lifespan patterns associated with shifts in life history and mating strategy. Although the plasticity of these sex differences will make it challenging to generalize from invertebrate to vertebrate systems, studies in nematodes have enabled empirical evaluation of predictions regarding the evolution of lifespan. These studies have highlighted how natural and sexual selection can generate divergent patterns of lifespan if the sexes are subject to different rates or sources of mortality, or if trade-offs between complex traits and longevity are resolved differently in each sex. Here, we integrate evidence derived mainly from nematodes that addresses the molecular and evolutionary basis of sex-specific aging and lifespan. Ultimately, we hope to generate a clearer picture of current knowledge in this area, and also highlight the limitations of our understanding. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Epidermal Wound Healing in the Nematode Caenorhabditis elegans

    PubMed Central

    Chisholm, Andrew D.

    2015-01-01

    Significance: Healing of epidermal wounds is a fundamentally conserved process found in essentially all multicellular organisms. Studies of anatomically simple and genetically tractable model invertebrates can illuminate the roles of key genes and mechanisms in wound healing. Recent Advances: The nematode skin is composed of a simple epithelium, the epidermis (also known as hypodermis), and an associated extracellular cuticle. Nematodes likely have a robust capacity for epidermal repair; yet until recently, relatively few studies have directly analyzed wound healing. Here we review epidermal wound responses and repair in the model nematode Caenorhabditis elegans. Critical Issues: Wounding the epidermis triggers a cutaneous innate immune response and wound closure. The innate immune response involves upregulation of a suite of antimicrobial peptides. Wound closure involves a Ca2+-triggered rearrangement of the actin cytoskeleton. These processes appear to be initiated independently, yet, their coordinated activity allows the animal to survive otherwise fatal skin wounds. Future Directions: Unanswered questions include the nature of the damage-associated molecular patterns sensed by the epidermis, the signaling pathways relaying Ca2+ to the cytoskeleton, and the mechanisms of permeability barrier repair. PMID:25945288

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

    PubMed

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

    2014-10-01

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

  1. Current research on the major nematode problems in Japan.

    PubMed

    Ichinohe, M

    1988-04-01

    AMONG IMPORTANT NEMATODE SPECIES OCCURRING IN JAPAN, CURRENT RESEARCH ACHIEVEMENTS WITH THE FOLLOWING FOUR NEMATODES ARE REVIEWED: 1) Soybean cyst nematode (SCN), Heterodera glycines - breeding for resistance, race determination, association with Cephalosporium gregatum in azuki bean disease, and isolation of hatching stimulant. 2) Potato-cyst nematode (PCN), Globodera rostochiensis - pathotype determination (Ro 1), breeding for resistance, and control recommendations. 3) Pinewood nematode (PWN), Bursaphelenchus xylophilus - primary pathogen in pine wilt disease, life cycle exhibiting a typical symbiosis with Japanese pine sawyer, Monochamus alternatus, and project for control. 4) Rice root nematodes (RRN), Hirschmanniella imamuri and H. oryzae - distribution of species, population levels in roots, and role of these nematodes in rice culture.

  2. A comparative analysis of benthic nematode assemblages from Zostera noltii beds before and after a major vegetation collapse

    NASA Astrophysics Data System (ADS)

    Materatski, Patrick; Vafeiadou, Anna-Maria; Ribeiro, Rui; Moens, Tom; Adão, Helena

    2015-12-01

    Benthic nematodes are widely regarded as very suitable organisms to monitor potential ecological effects of natural and anthropogenic disturbances in aquatic ecosystems. During 2008, the seagrass beds of Zostera noltii located in the Mira estuary (SW Portugal) disappeared completely. However, during 2009, slight symptoms of natural recovery were observed, a process which has since evolved intermittently. This study aims to investigate changes in patterns of nematode density, diversity, and trophic composition between two distinct habitat conditions: "before" the collapse of seagrass beds, and during the early recovery "after" the seagrass habitat loss, through the analysis of: i) temporal and spatial distribution patterns of nematode communities, and ii) the most important environmental variables influencing the nematode assemblages. The following hypotheses were tested: i) there would be differences in nematode assemblage density, biodiversity and trophic composition during both ecological conditions, "before" and "after"; and ii) there would be differences in nematode assemblage density, biodiversity and trophic composition at different sampling occasions during both ecological conditions. Nematode density and diversity were significantly different between the two ecological situations. A higher density was recorded before, but a higher diversity was evident after the collapse of Z. noltii. In spite of the disturbance caused by the seagrass habitat loss in the Mira estuary, the nematode trophic composition did not significantly differ between the before and after seagrass collapse situations. Despite the significant differences found among sampling occasions, a consistent temporal pattern was not evident. The response of nematode communities following this extreme event exhibited considerable resistance and resilience to the new environmental conditions.

  3. Does scavenging extend the host range of entomopathogenic nematodes (Nematoda: Steinernematidae)?

    PubMed

    Půza, Vladimír; Mrácek, Zdenĕk

    2010-05-01

    Living and freeze-killed natural and laboratory hosts, with different susceptibility to entomopathogenic nematodes, were exposed to the larvae of Steinernema affine and Steinernema kraussei in two different experimental arenas (Eppendorf tubes, Petri dishes), and the success of the colonisation and eventual progeny production were observed. Both nematodes were able to colonise both living and dead larvae of Galleria mellonella (Lepidoptera) and adult Blatella germanica (Blattodea) even though the progeny production in dead hosts was lower on average. Living carabid beetles, Poecilus cupreus, and elaterid larvae (Coleoptera) were resistant to the infection, however, both nematodes were able to colonise and multiply in several dead P. cupreus and in a majority of dead elaterid larvae. By scavenging, EPNs can utilise cadavers of insects that are naturally resistant to EPN infection, and so broaden their host range.

  4. The mucus-trap hypothesis on feeding of aquatic nematodes and implications for biodegradation and sediment texture.

    PubMed

    Riemann, Franz; Schrage, Marion

    1978-01-01

    Many aquatic nematodes continuously produce with their caudal and pharyngeal glands a slimy trace consisting of sticky, elastic threads which give an acid mucopolysaccharide reaction. Along these traces small particles adhere firmly thus making the traces visible at low magnifications. By creeping repeatedly on their traces the nematodes produce burrows and solid, branched concretions in fine sediments. By these activities soft bottoms acquire a particular framework texture which perhaps may, for instance in the deep sea, enable an interstitial, non-boring microfauna to thrive.The authors suppose that the copious mucus secretion of nematodes is mainly involved in nutrition and they present an hypothesis on the assumed mode of feeding (mucus-trap hypothesis): With their mucus threads these nematodes entrap small detritus particles, bacteria, and macromolecules which subsequently are browsed together with the mucus. The combination of an adhesive mucus thread and the particular mouth construction in nematodes represents a highly elaborated collecting and sorting system for food acquisition. In addition, decomposition processes of organic material coated by the mucus may contribute to a secondary food source which is controlled by nematodes. Feces are embedded within the mucus, and their remaining nutrient content may be subjected to a later re-utilization.

  5. Parasitic nematodes - from genomes to control.

    PubMed

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

    2007-08-19

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

  6. LABORATORY-ACQUIRED MYCOSES

    DTIC Science & Technology

    laboratory- acquired mycoses . Insofar as possible, the etiological fungus, type of laboratory, classification of personnel, type of work conducted, and other...pertinent data have been listed in this study. More than 288 laboratory- acquired mycoses are described here, including 108 cases of

  7. Acquired Idiopathic Generalized Anhidrosis.

    PubMed

    Gangadharan, Geethu; Criton, Sebastian; Surendran, Divya

    2015-01-01

    Acquired idiopathic generalized anhidrosis is a rare condition, where the exact pathomechanism is unknown. We report a case of acquired idiopathic generalized anhidrosis in a patient who later developed lichen planus. Here an autoimmune-mediated destruction of sweat glands may be the probable pathomechanism.

  8. Ascaroside Signaling is Widely Conserved Among Nematodes

    PubMed Central

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

    2012-01-01

    Summary 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. PMID:22503501

  9. Effects of Interactions of Auxin-Producing Bacteria and Bacterial-Feeding Nematodes on Regulation of Peanut Growths

    PubMed Central

    Xu, Li; Xu, Wensi; Jiang, Ying; Hu, Feng; Li, Huixin

    2015-01-01

    The influences of an IAA (indole-3-acetic acid)-producing bacterium (Bacillus megaterium) and two bacterial-feeding nematodes (Cephalobus sp. or Mesorhabditis sp.) on the growth of peanut (Arachis hypogaea L. cv. Haihua 1) after various durations of time were investigated in natural soils. The addition of bacteria and nematodes and incubation time all significantly affected plant growth, plant root growth, plant nutrient concentrations, soil nutrient concentrations, soil microorganisms and soil auxin concentration. The addition of nematodes caused greater increases in these indices than those of bacteria, while the addition of the combination of bacteria and nematodes caused further increases. After 42-day growth, the increases in soil respiration differed between the additions of two kinds of nematodes because of differences in their life strategies. The effects of the bacteria and nematodes on the nutrient and hormone concentrations were responsible for the increases in plant growth. These results indicate the potential for promoting plant growth via the addition of nematodes and bacteria to soil. PMID:25867954

  10. Previously unrecognized stages of species-specific colonization in the mutualism between Xenorhabdus bacteria and Steinernema nematodes.

    PubMed

    Chaston, John M; Murfin, Kristen E; Heath-Heckman, Elizabeth A; Goodrich-Blair, Heidi

    2013-09-01

    The specificity of a horizontally transmitted microbial symbiosis is often defined by molecular communication between host and microbe during initial engagement, which can occur in discrete stages. In the symbiosis between Steinernema nematodes and Xenorhabdus bacteria, previous investigations focused on bacterial colonization of the intestinal lumen (receptacle) of the nematode infective juvenile (IJ), as this was the only known persistent, intimate and species-specific contact between the two. Here we show that bacteria colonize the anterior intestinal cells of other nematode developmental stages in a species-specific manner. Also, we describe three processes that only occur in juveniles that are destined to become IJs. First, a few bacterial cells colonize the nematode pharyngeal-intestinal valve (PIV) anterior to the intestinal epithelium. Second, the nematode intestine constricts while bacteria initially remain in the PIV. Third, anterior intestinal constriction relaxes and colonizing bacteria occupy the receptacle. At each stage, colonization requires X. nematophila symbiosis region 1 (SR1) genes and is species-specific: X. szentirmaii, which naturally lacks SR1, does not colonize unless SR1 is ectopically expressed. These findings reveal new aspects of Xenorhabdus bacteria interactions with and transmission by theirSteinernema nematode hosts, and demonstrate that bacterial SR1 genes aid in colonizing nematode epithelial surfaces.

  11. Effects of interactions of auxin-producing bacteria and bacterial-feeding nematodes on regulation of peanut growths.

    PubMed

    Xu, Li; Xu, Wensi; Jiang, Ying; Hu, Feng; Li, Huixin

    2015-01-01

    The influences of an IAA (indole-3-acetic acid)-producing bacterium (Bacillus megaterium) and two bacterial-feeding nematodes (Cephalobus sp. or Mesorhabditis sp.) on the growth of peanut (Arachis hypogaea L. cv. Haihua 1) after various durations of time were investigated in natural soils. The addition of bacteria and nematodes and incubation time all significantly affected plant growth, plant root growth, plant nutrient concentrations, soil nutrient concentrations, soil microorganisms and soil auxin concentration. The addition of nematodes caused greater increases in these indices than those of bacteria, while the addition of the combination of bacteria and nematodes caused further increases. After 42-day growth, the increases in soil respiration differed between the additions of two kinds of nematodes because of differences in their life strategies. The effects of the bacteria and nematodes on the nutrient and hormone concentrations were responsible for the increases in plant growth. These results indicate the potential for promoting plant growth via the addition of nematodes and bacteria to soil.

  12. Previously unrecognized stages of species-specific colonization in the mutualism between Xenorhabdus bacteria and Steinernema nematodes

    PubMed Central

    Chaston, John M.; Murfin, Kristen E.; Heath-Heckman, Elizabeth A.; Goodrich-Blair, Heidi

    2013-01-01

    Summary The specificity of a horizontally transmitted microbial symbiosis is often defined by molecular communication between host and microbe during initial engagement, which can occur in discrete stages. In the symbiosis between Steinernema nematodes and Xenorhabdus bacteria, previous investigations focused on bacterial colonization of the intestinal lumen (receptacle) of the nematode infective juvenile (IJ), as this was the only known persistent, intimate, and species-specific contact between the two. Here we show that bacteria colonize the anterior intestinal cells of other nematode developmental stages in a species-specific manner. Also, we describe three processes that only occur in juveniles that are destined to become IJs. First, a few bacterial cells colonize the nematode pharyngeal-intestinal valve (PIV) anterior to the intestinal epithelium. Second, the nematode intestine constricts while bacteria initially remain in the PIV. Third, anterior intestinal constriction relaxes and colonizing bacteria occupy the receptacle. At each stage, colonization requires X. nematophila symbiosis region 1 (SR1) genes and is species-specific: X. szentirmaii, which naturally lacks SR1, does not colonize unless SR1 is ectopically expressed. These findings reveal new aspects of Xenorhabdus bacteria interactions with and transmission by their Steinernema nematode hosts, and demonstrate that bacterial SR1 genes aid in colonizing nematode epithelial surfaces. PMID:23480552

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

    PubMed

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

    2013-01-01

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

  14. The FLP-side of nematodes.

    PubMed

    McVeigh, Paul; Geary, Timothy G; Marks, Nikki J; Maule, Aaron G

    2006-08-01

    The central role of FMRFamide-like peptides (FLPs) in nematode motor and sensory capabilities makes FLP signalling an appealing target for new parasiticides. Accumulating evidence has revealed an astounding level of FLP sequence conservation and diversity in the phylum Nematoda, and preliminary work has begun to identify the nematode FLP receptor complement in Caenorhabditis elegans, with a view to investigating their basic biology and therapeutic potential. However, much work is needed to clarify the functional aspects of FLP signalling and how these peptides exert their effects at the organismal level. Here, we summarize our current knowledge of nematode FLP signalling.

  15. An evolutionary approach to identify potentially protective B cell epitopes involved in naturally acquired immunity to malaria and the role of EBA-175 in protection amongst denizens of Bolifamba, Cameroon.

    PubMed

    Nyasa, Raymond B; Kimbi, Helen K; Zofou, Denis; DeBarry, Jeremy D; Kissinger, Jessica C; Titanji, Vincent P K

    2016-05-20

    The search for a vaccine against malaria caused by Plasmodium falciparum has lasted for more than 100 years, with considerable progress in the identification of a number of vaccine candidates. The post-genomic era offers new opportunities for an expedited search using rational vaccine design and prioritization of key B-cell epitopes involved in natural acquired immunity. Malaria vaccine candidate genes that have reached clinical trial were searched on an evolutionary relationship tree, to determine their level of lineage-specificity. Ten other genes with similar protein features and level of lineage specificity to the vaccine candidates were randomly selected, and computationally evaluated for the presence of B-cell epitopes. The protein fragment with maximum probability of putative epitopes were synthesized and used in an ELISA experiment to determine the presence of antibodies to these peptides, in the serum of malaria patients and healthy malaria uninfected inhabitants from a malaria endemic region (Bolifamba), alongside with a vaccine candidate EBA-175. Two peptide fragments of 25 and 30 amino acid length from PF3D7_1233400 and PF3D7_1437500 respectively, coded as PF4-123 and PF4-143 were shown to contain B-cell epitope(s). Total IgG antibodies to these peptides were not significantly different between sick and healthy participants, but cytophilic antibodies to these peptides were significantly higher in healthy participants (p < 0.03). Total IgG to the vaccine candidate EBA-175 was significantly higher in sick participants than in healthy participants, likewise cytophilic antibodies (p < 0.04). Antibodies to the peptides PF4-123 and PF4-143 correlated negatively (p = 0.025 and 0.008 and r = -0.291 and -0.345, respectively) to parasite load. Total IgG antibodies to EBA-175 showed a negative correlation to parasite load (r = -0.144), which was not significant (p = 0.276). Duration of stay in Bolifamba also negatively correlated with parasite load (p

  16. Nematode endogenous small RNA pathways

    PubMed Central

    Hoogstrate, Suzanne W; Volkers, Rita JM; Sterken, Mark G; Kammenga, Jan E; Snoek, L Basten

    2014-01-01

    The discovery of small RNA silencing pathways has greatly extended our knowledge of gene regulation. Small RNAs have been presumed to play a role in every field of biology because they affect many biological processes via regulation of gene expression and chromatin remodeling. Most well-known examples of affected processes are development, fertility, and maintenance of genome stability. Here we review the role of the three main endogenous small RNA silencing pathways in Caenorhabditis elegans: microRNAs, endogenous small interfering RNAs, and PIWI-interacting RNAs. After providing an entry-level overview on how these pathways function, we discuss research on other nematode species providing insight into the evolution of these small RNA pathways. In understanding the differences between the endogenous small RNA pathways and their evolution, a more comprehensive picture is formed of the functions and effects of small RNAs. PMID:25340013

  17. Effects of Soil Textures on Infectivity of Root-Knot Nematodes on Carrot

    PubMed Central

    Kim, Eunji; Seo, Yunhee; Kim, Yong Su; Park, Yong; Kim, Young Ho

    2017-01-01

    This study was conducted to examine infectivity (penetration and gall and egg-mass formations) of the root-knot nematodes, Meloidogyne incognita and M. hapla, on carrots grown in soil conditions of 5 different soil textures consisting of bed-soil (b) and sand (s) mixtures (b-s mixtures) at the ratios of 10:0, 7:3, 5:5, 3:7, and 0:10. For M. incognita, the nematode penetration rates in b-s of 0:10 (100% sand) were significantly higher than in the other b-s mixtures, more greatly at 2 and 5 days after inoculation than at 10 DAI, while no significant differences in the penetration rates were mostly shown for M. hapla at the above DAI. However, for both nematodes, gall and egg-mass formations were remarkably increased in the b-s mixture of 0:10, compared to the other b-s mixtures, which is coincided with the general aspects of severe nematode infestations in sandy soils. This suggests the increased gall and egg-mass formations of M. incognita should be derived from the increased penetration rates in the sandy soil conditions, which provide a sufficient aeration due to coarse soil nature for the nematodes, leading to their mobility increased for the enhanced root penetration. For M. hapla, it is suggested that the sandy soil conditions affect positively on the healthy plant growth with little accumulation of the inhibitory materials and sufficient aeration, enhancing the nematode growth and feeding activities. All of these aspects provide information reliable for the development screening techniques efficient for the evaluation of the nematode resistance in the breeding programs. PMID:28167889

  18. Biochemical changes in grape rootstocks resulted from humic acid treatments in relation to nematode infection

    PubMed Central

    Kesba, Hosny H; El-Beltagi, Hossam S

    2012-01-01

    Objective To investigate the effect of humic acid on nematode infected, resistant and susceptible grapes in relation to lipid peroxidation and antioxidant mechanisms on selected biochemical parameters known as proactive substances. Methods The grape rootstocks, superior, superior/freedom and freedom were reacted differently to Meloidogyne incognita and Rotylenchulus reniformis according to rootstock progenitor. Two weeks after inoculation, two commercial products of humic acid were applied at the rate of (2, 4 mL or grams/plant) as soil drench. After 4 months, nematode soil populations were extracted and counted. A subsample of roots from each plant was stained and gall numbers, embedded stages per root were calculated, final population, nematode build up (Pf/Pi), average of eggs/eggmass were estimated. Subsamples of fresh root of each treatment were chemically analyzed. Results Freedom reduced significantly the nematode criteria and build up. Humic acid granules appeared to be more suppressive to nematode build up on superior and the higher dose on superior/freedom than liquid treatments. On freedom, all treatments reduced significantly the nematode build up regardless to the material nature. The higher dose was more effective than the lower one. As a result of humic acid applications, the malondialdehyde (MDA) and H2O2 contents were significantly reduced after humic acid treatments while the antioxidant compounds glutathione (GSH), ascorbic acid (ASA) and total phenol contents were significantly increased when compared with check. Antioxidant defense enzymes ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and polyphenol oxidase (PPO)showed significant increase in their specific activities in treated plants compared with nematode treated check. Conclusions Humic acid treatments improve the yield of grape by increasing the contents of antioxidant compounds and the specific activities of antioxidant enzymes. PMID:23569915

  19. Biochemical changes in grape rootstocks resulted from humic acid treatments in relation to nematode infection.

    PubMed

    Kesba, Hosny H; El-Beltagi, Hossam S

    2012-04-01

    To investigate the effect of humic acid on nematode infected, resistant and susceptible grapes in relation to lipid peroxidation and antioxidant mechanisms on selected biochemical parameters known as proactive substances. The grape rootstocks, superior, superior/freedom and freedom were reacted differently to Meloidogyne incognita and Rotylenchulus reniformis according to rootstock progenitor. Two weeks after inoculation, two commercial products of humic acid were applied at the rate of (2, 4 mL or grams/plant) as soil drench. After 4 months, nematode soil populations were extracted and counted. A subsample of roots from each plant was stained and gall numbers, embedded stages per root were calculated, final population, nematode build up (Pf/Pi), average of eggs/eggmass were estimated. Subsamples of fresh root of each treatment were chemically analyzed. Freedom reduced significantly the nematode criteria and build up. Humic acid granules appeared to be more suppressive to nematode build up on superior and the higher dose on superior/freedom than liquid treatments. On freedom, all treatments reduced significantly the nematode build up regardless to the material nature. The higher dose was more effective than the lower one. As a result of humic acid applications, the malondialdehyde (MDA) and H2O2 contents were significantly reduced after humic acid treatments while the antioxidant compounds glutathione (GSH), ascorbic acid (ASA) and total phenol contents were significantly increased when compared with check. Antioxidant defense enzymes ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and polyphenol oxidase (PPO)showed significant increase in their specific activities in treated plants compared with nematode treated check. Humic acid treatments improve the yield of grape by increasing the contents of antioxidant compounds and the specific activities of antioxidant enzymes.

  20. Acquired inflammatory demyelinating neuropathies.

    PubMed

    Ensrud, E R; Krivickas, L S

    2001-05-01

    The acquired demyelinating neuropathies can be divided into those with an acute onset and course and those with a more chronic course. The acute neuropathies present as Guillain-Barré syndrome and include acute inflammatory demyelinating polyradiculoneuropathy (AIDP), Miller Fisher syndrome, acute motor axonal neuropathy (AMAN), acute motor and sensory axonal neuropathy (AMSAN), and acute pandysautonomia. The chronic neuropathies are collectively known as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and include MADSAM (multifocal acquired demyelinating sensory and motor neuropathy, also know as Lewis-Sumner syndrome) and DADS (distal acquired demyelinating symmetric neuropathy) as variants. The clinical features, pathology, pathogenesis, diagnosis, treatment, rehabilitation, and prognosis of these neuropathies are discussed.

  1. Galactosylated Fucose Epitopes in Nematodes

    PubMed Central

    Yan, Shi; Bleuler-Martinez, Silvia; Plaza, David Fernando; Künzler, Markus; Aebi, Markus; Joachim, Anja; Razzazi-Fazeli, Ebrahim; Jantsch, Verena; Geyer, Rudolf; Wilson, Iain B. H.; Paschinger, Katharina

    2012-01-01

    The modification of α1,6-linked fucose residues attached to the proximal (reducing-terminal) core N-acetylglucosamine residue of N-glycans by β1,4-linked galactose (“GalFuc” epitope) is a feature of a number of invertebrate species including the model nematode Caenorhabditis elegans. A pre-requisite for both core α1,6-fucosylation and β1,4-galactosylation is the presence of a nonreducing terminal N-acetylglucosamine; however, this residue is normally absent from the final glycan structure in invertebrates due to the action of specific hexosaminidases. Previously, we have identified two hexosaminidases (HEX-2 and HEX-3) in C. elegans, which process N-glycans. In the present study, we have prepared a hex-2;hex-3 double mutant, which possesses a radically altered N-glycomic profile. Whereas in the double mutant core α1,3-fucosylation of the proximal N-acetylglucosamine was abolished, the degree of galactosylation of core α1,6-fucose increased, and a novel Galα1,2Fucα1,3 moiety attached to the distal core N-acetylglucosamine residue was detected. Both galactosylated fucose moieties were also found in two parasitic nematodes, Ascaris suum and Oesophagostomum dentatum. As core modifications of N-glycans are known targets for fungal nematotoxic lectins, the sensitivity of the C. elegans double hexosaminidase mutant was assessed. Although this mutant displayed hypersensitivity to the GalFuc-binding lectin CGL2 and the N-acetylglucosamine-binding lectin XCL, the mutant was resistant to CCL2, which binds core α1,3-fucose. Thus, the use of C. elegans mutants aids the identification of novel N-glycan modifications and the definition of in vivo specificities of nematotoxic lectins with potential as anthelmintic agents. PMID:22733825

  2. WormBase: Annotating many nematode genomes.

    PubMed

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

    2012-01-01

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

  3. Nematode molecular diagnostics: from bands to barcodes.

    PubMed

    Powers, Tom

    2004-01-01

    Nematodes are considered among the most difficult animals to identify. DNA-based diagnostic methods have already gained acceptance in applications ranging from quarantine determinations to assessments of biodiversity. Researchers are currently in an information-gathering mode, with intensive efforts applied to accumulating nucleotide sequence of 18S and 28S ribosomal genes, internally transcribed spacer regions, and mitochondrial genes. Important linkages with collateral data such as digitized images, video clips and specimen voucher web pages are being established on GenBank and NemATOL, the nematode-specific Tree of Life database. The growing DNA taxonomy of nematodes has lead to their use in testing specific short sequences of DNA as a "barcode" for the identification of all nematode species.

  4. How cellular slime molds evade nematodes.

    PubMed Central

    Kessin, R H; Gundersen, G G; Zaydfudim, V; Grimson, M

    1996-01-01

    We have found a predator-prey association between the social amoeba Dictyostelium discoideum and the free soil living nematode Caenorhabditis elegans. C. elegans feeds on the amoebae and multiplies indefinitely when amoebae are the sole food source. In an environment created from soil, D. discoideum grows and develops, but not in the presence of C. elegans. During development, C. elegans feeds on amoebae until they aggregate and synthesize an extracellular matrix called the slime sheath. After the sheath forms, the aggregate and slug are protected. Adult nematodes ingest Dictyostelium spores, which pass through the gut of the worm without loss of structure and remain viable. Nematodes kill the amoebae but disperse the spores. The sheath that is constructed when the social amoebae aggregate and the spore coats of the individual cells may protect against this predator. Individual amoebae may also protect themselves by secreting compounds that repel nematodes. Images Fig. 1 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:8643493

  5. Quantifying the Contribution of Entire Free-Living Nematode Communities to Carbon Mineralization under Contrasting C and N Availability

    PubMed Central

    Gebremikael, Mesfin Tsegaye; Steel, Hanne; Bert, Wim; Maenhout, Peter; Sleutel, Steven; De Neve, Stefaan

    2015-01-01

    To understand the roles of nematodes in organic matter (OM) decomposition, experimental setups should include the entire nematode community, the native soil microflora, and their food sources. Yet, published studies are often based on either simplified experimental setups, using only a few selected species of nematode and their respective prey, despite the multitude of species present in natural soil, or on indirect estimation of the mineralization process using O2 consumption and the fresh weight of nematodes. We set up a six-month incubation experiment to quantify the contribution of the entire free living nematode community to carbon (C) mineralization under realistic conditions. The following treatments were compared with and without grass-clover amendment: defaunated soil reinoculated with the entire free living nematode communities (+Nem) and defaunated soil that was not reinoculated (-Nem). We also included untreated fresh soil as a control (CTR). Nematode abundances and diversity in +Nem was comparable to the CTR showing the success of the reinoculation. No significant differences in C mineralization were found between +Nem and -Nem treatments of the amended and unamended samples at the end of incubation. Other related parameters such as microbial biomass C and enzymatic activities did not show significant differences between +Nem and -Nem treatments in both amended and unamended samples. These findings show that the collective contribution of the entire nematode community to C mineralization is small. Previous reports in literature based on simplified experimental setups and indirect estimations are contrasting with the findings of the current study and further investigations are needed to elucidate the extent and the mechanisms of nematode involvement in C mineralization. PMID:26393517

  6. Quantifying the Contribution of Entire Free-Living Nematode Communities to Carbon Mineralization under Contrasting C and N Availability.

    PubMed

    Gebremikael, Mesfin Tsegaye; Steel, Hanne; Bert, Wim; Maenhout, Peter; Sleutel, Steven; De Neve, Stefaan

    2015-01-01

    To understand the roles of nematodes in organic matter (OM) decomposition, experimental setups should include the entire nematode community, the native soil microflora, and their food sources. Yet, published studies are often based on either simplified experimental setups, using only a few selected species of nematode and their respective prey, despite the multitude of species present in natural soil, or on indirect estimation of the mineralization process using O2 consumption and the fresh weight of nematodes. We set up a six-month incubation experiment to quantify the contribution of the entire free living nematode community to carbon (C) mineralization under realistic conditions. The following treatments were compared with and without grass-clover amendment: defaunated soil reinoculated with the entire free living nematode communities (+Nem) and defaunated soil that was not reinoculated (-Nem). We also included untreated fresh soil as a control (CTR). Nematode abundances and diversity in +Nem was comparable to the CTR showing the success of the reinoculation. No significant differences in C mineralization were found between +Nem and -Nem treatments of the amended and unamended samples at the end of incubation. Other related parameters such as microbial biomass C and enzymatic activities did not show significant differences between +Nem and -Nem treatments in both amended and unamended samples. These findings show that the collective contribution of the entire nematode community to C mineralization is small. Previous reports in literature based on simplified experimental setups and indirect estimations are contrasting with the findings of the current study and further investigations are needed to elucidate the extent and the mechanisms of nematode involvement in C mineralization.

  7. Four transthyretin-like genes of the migratory plant-parasitic nematode Radopholus similis: members of an extensive nematode-specific family.

    PubMed

    Jacob, Joachim; Vanholme, Bartel; Haegeman, Annelies; Gheysen, Godelieve

    2007-11-01

    Screening 1154 ESTs from the plant-parasitic nematode Radopholus similis resulted in seven tags coding for proteins holding a transthyretin-like domain (PF01060). The seven ESTs corresponded to four different genes which were cloned from a cDNA library (accession numbers AM691117, AM691118, AM691119, AM691120). Transthyretin-like genes belong to a large family, different from the transthyretin and the transthyretin-related genes with whom they share some sequence similarity at the protein level. This similarity has caused an inconsistent use of different names and abbreviations in the past. To avoid further confusion, we introduce a standardized nomenclature for this gene family, and chose to name this barely characterized gene family ttl (as for transthyretin-like). Further examination of the identified genes, named Rs-ttl-1 to -4, showed that they are expressed in both juveniles and adults, but not in young embryos. Whole mount in situ hybridization revealed a distinct spatial expression pattern for two of the genes: Rs-ttl-1 is expressed in the tissues surrounding the vulva, whereas Rs-ttl-2 is expressed in the ventral nerve cord. The deduced protein sequences contain a putative signal peptide for secretion, pointing to an extracellular function of the mature proteins. Database screens showed that the ttl family is restricted to nematodes. Moreover, a HMMER search revealed that ESTs derived from ttl genes are more abundant in parasitic nematode libraries, with a bias towards the parasitic stages. Despite their abundance in nematodes, including the extensively studied model organism Caenorhabditis elegans, the function of TTL proteins remains obscure. Our data suggest a role in the nervous system. Even without insight into their biological function, the nematode-specific nature of this gene family makes it a promising target for nematicides or RNAi mediated control strategies against parasitic nematodes.

  8. Conserving and Enhancing Biological Control of Nematodes

    PubMed Central

    Timper, Patricia

    2014-01-01

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

  9. Conserving and enhancing biological control of nematodes.

    PubMed

    Timper, Patricia

    2014-06-01

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

  10. Hospital-acquired pneumonia

    MedlinePlus

    ... levels in the blood Sputum culture or sputum gram stain , to check what germs are causing the pneumonia ... Aspiration Immunodeficiency disorders Pneumonia - adults (community acquired) Patient Instructions Pneumonia in adults - discharge Review Date 2/2/ ...

  11. Acquired color vision deficiency.

    PubMed

    Simunovic, Matthew P

    2016-01-01

    Acquired color vision deficiency occurs as the result of ocular, neurologic, or systemic disease. A wide array of conditions may affect color vision, ranging from diseases of the ocular media through to pathology of the visual cortex. Traditionally, acquired color vision deficiency is considered a separate entity from congenital color vision deficiency, although emerging clinical and molecular genetic data would suggest a degree of overlap. We review the pathophysiology of acquired color vision deficiency, the data on its prevalence, theories for the preponderance of acquired S-mechanism (or tritan) deficiency, and discuss tests of color vision. We also briefly review the types of color vision deficiencies encountered in ocular disease, with an emphasis placed on larger or more detailed clinical investigations. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Acquired Cerebral Trauma: Epilogue.

    ERIC Educational Resources Information Center

    Bigler, Erin D., Ed.

    1988-01-01

    The article summarizes a series of articles concerning acquired cerebral trauma. Reviewed are technological advances, treatment, assessment, potential innovative therapies, long-term outcome, family impact of chronic brain injury, and prevention. (DB)

  13. Pneumonia - children - community acquired

    MedlinePlus

    ... CL, Bradley JS. Pediatric community-acquired pneumonia. In: Cherry JD, Harrison GJ, Kaplan SL, Steinback WJ, and Hotez PJ, eds. Feigin and Cherry's Textbook of Pediatric Infectious Diseases. 7th ed. Philadelphia, ...

  14. Interactions between Nematodes and Earthworms: Enhanced Dispersal of Steinernema carpocapsae

    PubMed Central

    Shapiro, D. I.; Berry, E. C.; Lewis, L. C.

    1993-01-01

    Dispersal of the nematode Steinernema carpocapsae (All strain), applied on the top or the bottom of soil columns, was tested in the presence or absence of two earthworm species, Lumbricus terrestris or Aporrectodea trapezoides. Nematode dispersal was estimated after a 2-week period with a bioassay against the greater wax moth, Galleria mellonella. Vertical dispersal of nematodes was increased in the presence of earthworms. When nematodes were placed on the surface of soil columns, significantly more nematodes dispersed to the lower half of the columns when either earthworm species was present than when earthworms were not present. When nematodes were placed on the bottom of soil columns, significantly more nematodes dispersed to the upper half of the columns when L. terrestris was present than when A. trapezoides was present or in the absence of earthworms. Because nematodes were found on the exterior and in the interior of earthworms, nematode dispersal may be enhanced by direct contact with the earthworms. PMID:19279757

  15. Impact of rotational grazing on management of gastrointestinal nematodes in weaned lambs

    USDA-ARS?s Scientific Manuscript database

    Gastrointestinal nematode (GIN) control for ‘natural’ or organic lamb production is needed, especially where Haemonchus contortus is prevalent. The objective was to determine the impact of rotational grazing on GIN infection of weaned lambs. In year 1, naturally infected Katahdin lambs (120 days of ...

  16. Multipartite Symbioses Among Fungi, Mites, Nematodes, and the Spruce Beetle, Dendroctonus rufipennis.

    Treesearch

    Yasmin Cardoza; John Moser; Kier Klepzizg; Raffa Kenneth

    2008-01-01

    The spruce beetle, Dendroctonus rufipennis, is an eruptive forest pest of signifcant economic and ecological importance. D. rufipennis has symbiotic associations with a number of microorganisms, especially the ophiostomatoid fungus Leptographium abietinum. The nature of this interaction is only partially understood. Additionally, mite and nematode associates can...

  17. Efficacy of oral, injectable and pour-on formulations of moxidectin against gastrointestinal nematodes in cattle in New Zealand.

    PubMed

    Leathwick, D M; Miller, C M

    2013-01-31

    The efficacy of moxidectin administered by different routes, against naturally acquired infections of gastrointestinal nematode parasites of cattle, was compared using faecal egg count reduction tests on 14 commercial farms throughout New Zealand. On each farm, groups of 15 calves were sampled for faecal nematode egg count and then treated with ivermectin administered orally, or with moxidectin administered either by the oral, subcutaneous injection or topical (pour-on) route. Samples were again collected 14 days after treatment and efficacy was calculated as the percentage reduction in-group mean egg count between the pre- and post-treatment samples. In addition, efficacy was calculated for individual animals, in order to compare the variability of the different treatments. On four farms untreated control groups were run and five animals from each of the control and all of the moxidectin-treated groups were bled over time to estimate plasma-moxidectin concentrations. Averaged across all tests, the reduction in faecal egg count was significantly greater after treatment with moxidectin oral (91.1%) than following treatment with moxidectin injection (55.5%) or with moxidectin pour-on (51.3%). Low efficacies were invariably against Cooperia oncophora. The oral treatments were significantly less variable in efficacy than the injection and pour-on treatments. Moxidectin concentrations in plasma were highest following subcutaneous injection and lowest following pour-on administration. Plasma levels following oral administration were intermediate, being significantly lower than post-injection and significantly higher than post-pour-on. There was no evidence of transfer of moxidectin to untreated animals through licking. Based on these results, along with those of other studies, it is proposed that oral administration of macrocyclic lactone anthelmintics results in higher concentrations of active reaching the target worms in the gastrointestinal tract than following either

  18. Characterizations of kinetic power and propulsion of the nematode Caenorhabditis elegans based on a micro-particle image velocimetry system.

    PubMed

    Kuo, Wan-Jung; Sie, Yue-Syun; Chuang, Han-Sheng

    2014-03-01

    Quantifying the motility of micro-organisms is beneficial in understanding their biomechanical properties. This paper presents a simple image-based algorithm to derive the kinetic power and propulsive force of the nematode Caenorhabditis elegans. To avoid unnecessary disturbance, each worm was confined in an aqueous droplet of 0.5 μl. The droplet was sandwiched between two glass slides and sealed with mineral oil to prevent evaporation. For motion visualization, 3-μm fluorescent particles were dispersed in the droplet. Since the droplet formed an isolated environment, the fluid drag and energy loss due to wall frictions were associated with the worm's kinetic power and propulsion. A microparticle image velocimetry system was used to acquire consecutive particle images for fluid analysis. The short-time interval (Δt < 20 ms) between images enabled quasi real-time measurements. A numerical simulation of the flow in a straight channel showed that the relative error of this algorithm was significantly mitigated as the image was divided into small interrogation windows. The time-averaged power and propulsive force of a N2 adult worm over three swimming cycles were estimated to be 5.2 ± 3.1 pW and 1.0 ± 0.8 nN, respectively. In addition, a mutant, KG532 [kin-2(ce179) X], and a wild-type (N2) worm in a viscous medium were investigated. Both cases showed an increase in the kinetic power as compared with the N2 worm in the nematode growth medium due to the hyperactive nature of the kin-2 mutant and the high viscosity medium used. Overall, the technique deals with less sophisticated calculations and is automation possible.

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

    PubMed

    Silvestre, A; Cabaret, J

    2004-06-01

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

  20. Biocontrol: Fungi as Nematode Control Agents

    PubMed Central

    Mankau, R.

    1980-01-01

    The fungal antagonists of nematodes consist of a great variety of organisms belonging to widely divergent orders and families of fungi. They include the nematode-trapping fungi, endoparasitic fungi, parasites of nematode eggs and cysts, and fungi which produce metabolites toxic to nematodes. The diversity, adaptations, and distribution of nematode-destroying fungi and taxonomic problems encountered in their study are reviewed. The importance of nemato-phagous fungi in soil biology, with special emphasis on their relationship to populations of plant-parasitic nematodes, is considered. While predacious fungi have long been investigated as possible biocontrol agents and have often exhibited spectacular results in vitro, their performance in field studies has generated little enthusiasm among nematologists. To date no species has demonstrated control of any plant pest to a degree achieved with nematicides, but recent studies have provided a much clearer concept of possibilities and problems in the applied use of fungal antagonists. The discovery of new species, which appear to control certain pests effectively under specific conditions, holds out some promise that fungi may be utilized as alternatives to chemical control after a more thorough and expanded study of their biology and ecology. PMID:19300699

  1. Role of horizontal gene transfer in the evolution of plant parasitism among nematodes.

    PubMed

    Mitreva, Makedonka; Smant, Geert; Helder, Johannes

    2009-01-01

    Horizontal gene transfer (HGT) implies the non-sexual exchange of genetic material between species - in some cases even across kingdoms. Although common among Bacteria and Archaea, HGTs from pro- to eukaryotes and between eukaryotes were thought to be extremely rare. Recent studies on intracellular bacteria and their hosts seriously question this view. Recipient organisms could benefit from HGT as new gene packages could allow them to broaden or change their diet, colonize new habitats, or survive conditions that previously would have been lethal.About a decade ago, plant parasitic nematodes were shown to produce and secrete cellulases. Prior to this, animals were thought to fully depend on microbial symbionts for the breakdown of plant cell walls. This discovery prompted Keen and Roberts (1) to hypothesize that the ability of nematodes to parasitize plants was acquired by HGT from soil bacteria to (ancestral) bacterivorous nematodes. Since the identification of the first nematode cellulases, many more plant cell wall-degrading enzymes (CWDE) have been identified in a range of plant parasitic nematode species.Here we discuss a number of criteria that can be used to underpin an HGT claim. HGT requires close physical contact between donor and recipient, and this could be achieved in, for example, a symbiont-host, or a trophic relationship. The former type of relationship was indeed shown to potentially result in the transfer of genetic material (e.g., Brugia malayi and Wolbachia). However, currently known endosymbionts of nematodes may not be the source of CWDEs. Remarkably, all cellulases discovered so far within the order Tylenchida belong to a single glycoside hydrolase family (GHF5). A range of soil bacteria harbours GHF5 cellulases, but of course nothing can be said about the gene content of soil bacteria at the time HGT took place (if at all). We suggest that characterisation of cellulases (and other CWDEs) and their genomic organisation in more basal

  2. Betaine acts on a ligand-gated ion channel in the nervous system of the nematode C. elegans.

    PubMed

    Peden, Aude S; Mac, Patrick; Fei, You-Jun; Castro, Cecilia; Jiang, Guoliang; Murfitt, Kenneth J; Miska, Eric A; Griffin, Julian L; Ganapathy, Vadivel; Jorgensen, Erik M

    2013-12-01

    Prior to the advent of synthetic nematocides, natural products such as seaweed were used to control nematode infestations. The nematocidal agent in seaweed is betaine, an amino acid that functions as an osmolyte and methyl donor. However, the molecular mechanisms of betaine toxicity are unknown. We identified the betaine transporter SNF-3 and the betaine receptor ACR-23 in the nematode C. elegans. Mutating snf-3 in a sensitized background caused the worms to be hypercontracted and paralyzed, presumably as a result of excess extracellular betaine. These behavioral defects were suppressed by mutations in acr-23, which encodes a ligand-gated cation channel of the cys-loop family. ACR-23 was activated by betaine and functioned in the mechanosensory neurons to maintain basal levels of locomotion. However, overactivation of the receptor by excess betaine or by the allosteric modulator monepantel resulted in hypercontraction and death of the nematode. Thus, monepantel targets a betaine signaling pathway in nematodes.

  3. Bacteria used in the biological control of plant-parasitic nematodes: populations, mechanisms of action, and future prospects.

    PubMed

    Tian, Baoyu; Yang, Jinkui; Zhang, Ke-Qin

    2007-08-01

    As a group of important natural enemies of nematode pests, nematophagous bacteria exhibit diverse modes of action: these include parasitizing; producing toxins, antibiotics, or enzymes; competing for nutrients; inducing systemic resistance of plants; and promoting plant health. They act synergistically on nematodes through the direct suppression of nematodes, promoting plant growth, and facilitating the rhizosphere colonization and activity of microbial antagonists. This review details the nematophagous bacteria known to date, including parasitic bacteria, opportunistic parasitic bacteria, rhizobacteria, Cry protein-forming bacteria, endophytic bacteria and symbiotic bacteria. We focus on recent research developments concerning their pathogenic mechanisms at the biochemical and molecular levels. Increased understanding of the molecular basis of the various pathogenic mechanisms of the nematophagous bacteria could potentially enhance their value as effective biological control agents. We also review a number of molecular biological approaches currently used in the study of bacterial pathogenesis in nematodes. We discuss their merits, limitations and potential uses.

  4. Betaine acts on a ligand-gated ion channel in the nervous system of the nematode C. elegans

    PubMed Central

    Peden, Aude S.; Mac, Patrick; Fei, You-Jun; Castro, Cecilia; Jiang, Guoliang; Murfitt, Kenneth J.; Miska, Eric A.; Griffin, Julian L.; Ganapathy, Vadivel; Jorgensen, Erik M.

    2014-01-01

    Prior to the advent of synthetic nematocides, natural products such as seaweed were used to control nematode infestations. The nematocidal agent in seaweed is betaine, an amino acid that functions as an osmolyte and methyl donor. However, the molecular mechanisms of betaine toxicity are unknown. Here, we identify the betaine transporter SNF-3 and a betaine receptor ACR-23 in the nematode C. elegans. Mutating snf-3 in a sensitized background causes the animals to be hypercontracted and paralyzed, presumably because of excess extracellular betaine. These behavioral defects are suppressed by mutations in acr-23, which encodes a ligand-gated cation channel of the cys-loop family. ACR-23 is activated by betaine and functions in the mechanosensory neurons to maintain basal levels of locomotion. However, overactivation of the receptor by excess betaine or by the allosteric modulator monepantel causes hypercontraction and death of the nematode. Thus, monepantel targets a betaine signaling pathway in nematodes. PMID:24212673

  5. Marine Nematode Taxonomy in Africa: Promising Prospects Against Scarcity of Information.

    PubMed

    Boufahja, Fehmi; Semprucci, Federica; Beyrem, Hamouda; Bhadury, Punyasloke

    2015-09-01

    From the late 19th century, Africa has faced heavy exploitation of its natural resources with increasing land/water pollution, and several described species have already become extinct or close to extinction. This could also be the case for marine nematodes, which are the most abundant and diverse benthic group in marine sediments, and play major roles in ecosystem functioning. Compared to Europe and North America, only a handful of investigations on marine nematodes have been conducted to date in Africa. This is due to the scarcity of experienced taxonomists, absence of identification guides, as well as local appropriate infrastructures. A pivotal project has started recently between nematologists from Africa (Tunisia), India, and Europe (Italy) to promote taxonomic study and biodiversity estimation of marine nematodes in the African continent. To do this, as a first step, collection of permanent slides of marine nematodes (235 nominal species and 14 new to science but not yet described) was recently established at the Faculty of Sciences of Bizerte (Tunisia). Capacity building of next generation of African taxonomists have been carried out at level of both traditional and molecular taxonomy (DNA barcoding and next-generation sequencing [NGS]), but they need to be implemented. Indeed, the integration of these two approaches appears crucial to overcome lack of information on the taxonomy, ecology, and biodiversity of marine nematodes from African coastal waters.

  6. Nematode Fauna of Tropical Rainforest in Brazil: A Descriptive and Seasonal Approach

    PubMed Central

    Cardoso, Mercia S. O.; Pedrosa, Elvira M. R.; Ferris, Howard; Rolim, Mario M.; Oliveira, Lamartine S. C.

    2016-01-01

    Studies of nematode assemblages in natural ecosystems can contribute to better understanding of the occurrence, relevance, and ecology of plant-parasitic and other soil nematodes. Nematode assemblages and environmental parameters (organic matter, water content (WC), bulk density (BD), total porosity (Po), soil respiration, and soil texture) were investigated in two seasons (rainy and dry) in two forest areas of the Zona da Mata, Pernambuco State. The aim of our research was to evaluate the heterogeneity between two locations and seasons in the Brazilian Atlantic Forest. Structure and composition of the nematode assemblages differed between areas and across time. Rhabditidae dominated the rainy season in both forest soils. Rarefaction curves (RC) suggest that sampling to detect more nematode taxa should be more intensive in the rainy season. The forest soils have complex, stable soil food webs with high connectance and decomposition channels dominated by bacteria. The predator–prey relationships were not affected by changes in soil properties that fluctuate with time. PMID:27418705

  7. Interaction of free-living marine nematodes in the artificial mangrove environment (Southeast Coast of India).

    PubMed

    Ansari, K G Mohamed Thameemul; Manokaran, S; Raja, S; Lyla, P S; Khan, S Ajmal

    2014-01-01

    Free-living marine nematode diversity was analyzed between Avicennia marina and Rhizophora mucronata mangrove covers of the Vellar Estuary (southeast coast of India). A total of 4,976 specimens of free-living marine nematodes were collected in 56 species. Comparatively, a higher species richness was obtained for A. marina (52 species) than for R. mucronata (44 species), whereas 40 species commonly existed in both mangrove covers. A higher density of nematodes was found in sediments of sandy nature, whereas there was lower total organic carbon compared to silt/clay composition; epigrowth feeders were dominant over the other feeding groups based on organic enrichment in surface sediments. Principal component analysis clearly explained the relationship between the environmental parameters of various months. Higher R values of analysis of similarities revealed significant differences in nematode assemblages between months, and it was quite evident by non-metric multidimensional scaling. Diversity indices showed higher values in the dry months. RELATE analysis explained serial changes in nematode species composition between months, and a relationship between biotic and abiotic variables was clarified using the BIO-ENV procedure. Viscosia spp., Metachromadora spp., Theristus spp., and Sphaerolaimus spp. were candidate species of A. marina leaf interaction by observation.

  8. Marine Nematode Taxonomy in Africa: Promising Prospects Against Scarcity of Information

    PubMed Central

    Boufahja, Fehmi; Semprucci, Federica; Beyrem, Hamouda; Bhadury, Punyasloke

    2015-01-01

    From the late 19th century, Africa has faced heavy exploitation of its natural resources with increasing land/water pollution, and several described species have already become extinct or close to extinction. This could also be the case for marine nematodes, which are the most abundant and diverse benthic group in marine sediments, and play major roles in ecosystem functioning. Compared to Europe and North America, only a handful of investigations on marine nematodes have been conducted to date in Africa. This is due to the scarcity of experienced taxonomists, absence of identification guides, as well as local appropriate infrastructures. A pivotal project has started recently between nematologists from Africa (Tunisia), India, and Europe (Italy) to promote taxonomic study and biodiversity estimation of marine nematodes in the African continent. To do this, as a first step, collection of permanent slides of marine nematodes (235 nominal species and 14 new to science but not yet described) was recently established at the Faculty of Sciences of Bizerte (Tunisia). Capacity building of next generation of African taxonomists have been carried out at level of both traditional and molecular taxonomy (DNA barcoding and next-generation sequencing [NGS]), but they need to be implemented. Indeed, the integration of these two approaches appears crucial to overcome lack of information on the taxonomy, ecology, and biodiversity of marine nematodes from African coastal waters. PMID:26527841

  9. A survey of the gastrointestinal nematodes of Spanish ibex (Capra pyrenaica) in a high mountain habitat.

    PubMed

    Pérez, Jesús M; Granados, José E; Pérez, M Carmen; Márquez, Francisco J; Ferroglio, Ezio; Rossi, Luca

    2003-04-01

    We analyzed the content of the abomasum (n = 79) and small intestine (n = 83) of Spanish ibex from Sierra Nevada Natural Park, southern Spain. Fifteen species of trichostrongylid nematodes were identified, 4 of which were found for the first time in this host, i.e., Nematodirus fillicollis, N. oiratianus, Ostertagia lyrata, and O. ostertagi. Teladorsagia circumcincta and Marshallagia marshalli were the most abundant abomasal species, whereas N. abnormalis, N. davtiani, and N. oiratianus were dominant in the small intestine. Counts of both abomasal and intestinal nematodes were generally low (year-round-median = 292 and 94 worms, respectively), and significantly lower numbers of M. marshalli, N. davtiani, and N. oiratianus were found in summer. No sex-related differences in helminth abundance were found, but young ibex harbored significantly more N. davtiani and N. oiratianus than adults. The presence of scabies was not related to increased nematode counts.

  10. Are changes in the structure of nematode assemblages reliable indicators of moderate petroleum contamination?

    PubMed

    Leite, Daniel Silva; Sandrini-Neto, Leonardo; Camargo, Manuela Zeglin; Thomas, Micheli Cristina; Lana, Paulo C

    2014-06-15

    This study assesses through a multiple before-after-control-impact (MBACI) design the effects of diesel oil on the structure of nematode assemblages in unvegetated tidal flats of a subtropical estuary. Oil-exposed treatments were contrasted with controls for a duration of four successive days before and after an experimental spill in three distinct areas of the Paranaguá Estuarine Complex (Southern Brazil). No significant differences were observed in nematode total density, number of taxa and the overall assemblage structure between the control and impact treatments from before to after the experimental spill. This reinforces the idea that, despite being good indicators of environmental stress, free-living marine nematodes are able to tolerate low concentrations of hydrocarbons and to survive in moderately contaminated areas. We also show that robust experimental designs are useful to avoid confounding expected natural variability with the effects of a mild impact.

  11. Light Intensity and Quality Effects on Reproduction of Plant-Parasitic Nematodes

    PubMed Central

    Barker, K. R.; Hussey, R. S.; Yang, H.

    1975-01-01

    Growing cotton in a greenhouse with 12-h of supplemental light [8,608 lux (800 ft-c) from combination of mercury and Lucalux® lamps] resulted in 2 × to > 3 × greater reproduction of Meloidogyne incognita and Belonolaimus longicaudatus as compared to natural light alone. Rate of increase of Hoplolaimus galeatus was affected little in this experiment. In a second experiment under controlled conditions in a phytotron, light source and intensity had greater influence on the reproduction of Heterodera glycines and Pratylenchus penetrans on soybean than on B. longicaudatus. Fluorescent plus incandescent and metal halide light sources resulted in the greatest nematode reproduction. Lucalux lamps resulted in much lower rates of nematode increase than other light sources. Rates of nematode increase on soybean under the different light sources in the phytotron generally were positively related to plant growth. PMID:19308183

  12. Nature

    NASA Astrophysics Data System (ADS)

    Heinhorst, Sabine; Cannon, Gordon

    1997-01-01

    The fact that two of the original articles by this year's Nobel laureates were published in Nature bears witness to the pivotal role of this journal in documenting pioneering discoveries in all areas of science. The prize for Physiology or Medicine was awarded to immunologists Peter C. Doherty (University of Tennessee) and Rolf M. Zinkernagel (University of Zurich, Switzerland), honoring work that, in the 1970s, laid the foundation for our current understanding of the way in which our immune system differentiates between healthy cells and virus-infected ones that are targeted for destruction (p 465 in the October 10 issue of vol. 383). Three researchers share the Chemistry award for their discovery of C60 buckminsterfullerenes. The work by Robert Curl, Richard Smalley (both at Rice University), and Harry Kroto (University of Sussex, UK) has led to a burst of new approaches to materials development and in carbon chemistry (p 561 of the October 17 issue of vol. 383). This year's Nobel prize in physics went to three U.S. researchers, Douglas Osheroff (Stanford University) and David M. Lee and Robert C. Richardson (Cornell University), who were honored for their work on superfluidity, a frictionless liquid state, of supercooled 3He (p 562 of the October 17 issue of vol. 383).

  13. Influence of Metalaxyl on Three Nematodes of Citrus

    PubMed Central

    Kaplan, David T.

    1983-01-01

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

  14. Influence of metalaxyl on three nematodes of citrus.

    PubMed

    Kaplan, D T

    1983-07-01

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

  15. Nematode Trophic Structure in Conventional and No-Tillage Agroecosystems

    PubMed Central

    Parmelee, Robert W.; Alston, Diane G.

    1986-01-01

    The effect of tillage intensity on nematode community trophic structure and the role of nematodes in the regulation of decomposition rates in agroecosystems were examined. Conventional (CT) and no-tillage (NT) agroecosystems were sampled monthly for 1 year. Tillage affected nematode trophic structure and total abundance. Monthly mean densities of bacterivorous, fungivorous, and total nematodes were greater in CT than in NT plots. In the summer, however, fungivorous and plant parasitic nematodes were more abundant in NT. No difference was detected for omnivore-predator nematodes. PMID:19294199

  16. Induced resistance to nematodes in cotton: a novel contribution to nematode management.

    USDA-ARS?s Scientific Manuscript database

    Induced resistance against plant-parasitic nematodes has not previously been shown in cotton. We tested whether co-infection of cotton by Meloidogyne incognita and Rotylenchulus reniformis affected population levels of either nematode compared to single-species infection. In split-root experiments, ...

  17. Controlling gastrointestinal nematodes in cattle by Bacillus species.

    PubMed

    Pinto, Natália Berne; de Castro, Leonardo Mortagua; de Almeida Capella, Gabriela; Motta, Tairan Ourique; de Souza Stori de Lara, Ana Paula; de Moura, Micaele Quintana; Berne, Maria Elisabeth Aires; Leite, Fábio Pereira Leivas

    2017-10-15

    In this study, we tested the in vitro and in vivo larvicidal activity of Bacillus species against gastrointestinal nematodes in cattle, and their viability in the presence of anthelmintics. For in vitro tests, cattle feces naturally infected with trichostrongylides were incubated with spore suspensions of Bacillus circulans (Bcir), B. thuringiensis var. osvaldocruzi (Bto), B. thuringiensis var. israelensis (Bti) or B. thuringiensis var. kurstaki (Btk). Subsequently, residual larvae were counted and identified. All of the Bacillus species showed 60% or more larvicidal effects. Bcir and Bti were selected to be incubated with anthelmintics (moxidectin, nitroxynil and levamisole), and after 24, 72, and 144h, their viability was evaluated. Bti showed highest drug resistance, maintaining a concentration of 1×10(7)CFU/mL. Based on this result, Bti was selected for in vivo tests on calves naturally infected with gastrointestinal nematodes. The calves were dived into four groups: Group 1, Bti suspension of ∼1×10(9)CFU orally administered; Group 2, Bti suspension of ∼1×10(9)CFU orally administered with levamisole (subcutaneously, 150mg); Group 3, only levamisole (subcutaneously, 150mg), and Group 4 untreated. Then 24 and 48h after treatment, larvae numbers were counted. We observed a reduction of 84%, 100%, and 100% after 48h of treatment, respectively, for Groups 1, 2 and 3 treatments in comparison with the untreated. The tested Bacillus species showed larvicidal activity against bovine trichostrongylides, and its association with anthelmintics. It may serve as a promising integrated alternative for control of gastrointestinal nematodes in cattle. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Distribution of the entomopathogenic nematodes from La Rioja (Northern Spain).

    PubMed

    Campos-Herrera, Raquel; Escuer, Miguel; Labrador, Sonia; Robertson, Lee; Barrios, Laura; Gutiérrez, Carmen

    2007-06-01

    Entomopathogenic nematodes (EPNs) distribution in natural areas and crop field edges in La Rioja (Northern Spain) has been studied taking into account environmental and physical-chemical soil factors. Five hundred soil samples from 100 sites of the most representative habitats were assayed for the presence of EPNs. The occurrence of EPNs statistically fitted to a negative binomial distribution, which pointed out that the natural distribution of these nematodes in La Rioja was in aggregates. There were no statistical differences (p < or = 0.05) in the abundance of EPNs to environmental and physical-chemical variables, although, there were statistical differences in the altitude, annual mean air temperature and rainfall, potential vegetation series and moisture percentage recovery frequency. Twenty-seven samples from 14 sites were positive for EPNs. From these samples, twenty isolates were identified to a species level and fifteen strains were selected: 11 Steinernema feltiae, two S. carpocapsae and two S. kraussei strains. S. kraussei was isolated from humid soils of cool and high altitude habitats and S. carpocapsae was found to occur in heavy soils of dry and temperate habitats. S. feltiae was the most common species with a wide range of altitude, temperature, rainfall, pH and soil moisture, although this species preferred sandy soils. The virulence of nematode strains were assessed using G. mellonella as insect host, recording the larval mortality percentage and the time to insect die, as well as the number of infective juveniles produced to evaluate the reproductive potential and the time tooks to leave the insect cadaver to determinate the infection cycle length. The ecological trends and biological results are discussed in relationship with their future use as biological control.

  19. Natural acquired inhibitory antibodies to Plasmodium vivax Duffy binding protein (PvDBP-II) equally block erythrocyte binding of homologous and heterologous expressed PvDBP-II on the surface of COS-7 cells.

    PubMed

    Valizadeh, Vahideh; Zakeri, Sedigheh; Mehrizi, Akram A; Mirkazemi, Sedigheh; Djadid, Navid D

    2016-02-01

    The binding domain of Plasmodium vivax Duffy binding protein (PvDBP-II) is a promising blood-stage vaccine candidate for vivax malaria. For the development of a successful vivax malaria vaccine based on DBP-II, the antigenic diversity and also naturally occurring functional antibodies to different PvDBP-II variant types in the various populations must be determined. However, similar to other blood-stage antigens, allelic variation within the PvDBP-II is a fundamental challenge for the development of a broadly efficient vaccine. The present study was performed to define whether the polymorphisms in PvDBP-II influence the nature of functional inhibitory activity of naturally acquired or induced anti-DBP-II antibodies in mice. In this investigation, five genetically distinct variants of PvDBP-II were transiently expressed on the COS-7 cell surface. Erythrocyte-binding inhibition assay (EBIA) was performed using human sera infected with corresponding and non-corresponding P. vivax variants as well as by the use of mice sera immunized with different expressed recombinant PvDBP-IIs. EBIA results showed that the inhibitory percentage varied between 50 and 63 % by using sera from infected individuals, and in case of mouse antisera, inhibition was in the range of 76-86 %. Interestingly, no significant difference was detected in red blood cell binding inhibition when different PvDBP-II variants on the COS-7 cell surfaces were incubated with heterologous and homologous sera infected with PvDBP-II variants. This suggests that the detected polymorphisms in all five forms of PvDBP-II may not affect functional activity of anti-DBP-II antibodies. In conclusion, our results revealed that there are functional cross-reactive antibody responses to heterologous PvDBP-II variants that might provide a broader inhibitory response against all, or at least the majority of strains compared to single allele of this protein that should be considered in development of PvDBP-II-based vaccine.

  20. Ecology in the service of biological control: the case of entomopathogenic nematodes.

    PubMed

    Gaugler, R; Lewis, Edwin; Stuart, Robin J

    1997-02-01

     Biological control manipulations of natural enemies to reduce pest populations represent large-scale ecological experiments that have both benefited from and contributed to various areas of modern ecology. Unfortunately, economic expediency and the need for rapid implementation often require that biological control programs be based more on trial and error than on sound ecological theory and testing. This approach has led to some remarkable successes but it has also produced dismal failures. This point is particularly well illustrated in the historical development and use of entomopathogenic nematodes for the biological control of insect pests. Intense effort has focused on developing these natural enemies as alternatives to chemical insecticides, in part because laboratory assays indicated that these nematodes possess a broad host range. This illusory attribute launched hundreds of field releases, many of which failed due to ecological barriers to infection that are not apparent from laboratory exposures, where conditions are optimal and host-parasite contact assured. For example, the entomopathogenic nematode Steinernema carpocapsae is a poor choice to control scarab larvae because this nematode uses an ambusher foraging strategy near the soil surface whereas the equally sedentary scarab remains within the soil profile, shows a weak host recognition response to scarabs, has difficulty overcoming the scarab immune response, and has low reproduction in this host. Conversely, two other nematodes, Heterorhabditis bacteriophora and S. glaseri, are highly adapted to parasitize scarabs: they use a cruising foraging strategy, respond strongly to scarabs, easily overcome the immune response, and reproduce well in these hosts. Increased understanding of the ecology of entomopathogenic nematodes has enabled better matches between parasites and hosts, and more accurate predictions of field performance. These results underline the importance of a strong partnership between

  1. In-vitro predatory activity of nematophagous fungi from Costa Rica with potential use for controlling sheep and goat parasitic nematodes.

    PubMed

    Soto-Barrientos, Natalia; de Oliveira, Jaqueline; Vega-Obando, Rommel; Montero-Caballero, Danilo; Vargas, Bernardo; Hernández-Gamboa, Jorge; Orozco-Solano, Claudio

    2011-03-01

    In tropical and subtropical regions of the world, parasitic diseases are a main cause of losses in livestock productivity. The increased acquired resistence to anthelmintics by gastrointestinal nematodes, requires biological control be considered as a potential feasible and effective alternative. The most effective natural soil enemies of nematodes are nematophagous fungi. In order to collect and identify predator nematophagous fungi (PNF), samples were obtained from 51 farms distributed throughout the seven provinces of Costa Rica. The origin samples included: soil from different crops (potatoes, tomatoes, bananas, ornamental plants, squash and coffee); animal feces (cattle, sheep, goat and horse); soil and fallen leaves from forest; and plants with signs of nematode infection. Each sample was processed using three techniques for the extraction of fungi from soil: sprinkling technique, soil dilution and humidity chamber. Twenty four strains of nematophagous fungi were found in 19 farms; 83.3% of the fungi were isolated by sprinkling technique. The following fungi were identified: Arthrobotrys oligospora (n = 13); Candelabrella musiformis (n = 9); and for the first time there was isolation of A. conoides (n = 1) and A. dactyloides (n = 1) in the country. Moreover, 16 strains from Trichoderma (n=13), Beauveria (n = 1), Clonostachys (n = 1) and Lecanicillium (n = 1) were obtained. In addition, pH of each possible fungal isolation source was measured, and it varied from 5.2 to 9.9, however PNF isolates fell within the range of 5.6 to 7.5. The PNF strains were cultivated in four different media for the production of chhlamydospores: potato dextrose agar (PDA); corn meal agar (CMA); malt extract agar (MEA) and potato carrot agar (PCA). Out of these cultures, 95.8% of the strains formed chlamydospores primarily in the PCA. Of these strains, the profilic spore producers were subjected to ruminant artificial gastrointestinal conditions. A total of 14 fungi were tested, out

  2. Interspecific Nematode Signals Regulate Dispersal Behavior

    PubMed Central

    Kaplan, Fatma; Alborn, Hans T.; von Reuss, Stephan H.; Ajredini, Ramadan; Ali, Jared G.; Akyazi, Faruk; Stelinski, Lukasz L.; Edison, Arthur S.; Schroeder, Frank C.; Teal, Peter E.

    2012-01-01

    Background Dispersal is an important nematode behavior. Upon crowding or food depletion, the free living bacteriovorus nematode Caenorhabditis elegans produces stress resistant dispersal larvae, called dauer, which are analogous to second stage juveniles (J2) of plant parasitic Meloidogyne spp. and infective juveniles (IJ)s of entomopathogenic nematodes (EPN), e.g., Steinernema feltiae. Regulation of dispersal behavior has not been thoroughly investigated for C. elegans or any other nematode species. Based on the fact that ascarosides regulate entry in dauer stage as well as multiple behaviors in C. elegans adults including mating, avoidance and aggregation, we hypothesized that ascarosides might also be involved in regulation of dispersal behavior in C. elegans and for other nematodes such as IJ of phylogenetically related EPNs. Methodology/Principal Findings Liquid chromatography-mass spectrometry analysis of C. elegans dauer conditioned media, which shows strong dispersing activity, revealed four known ascarosides (ascr#2, ascr#3, ascr#8, icas#9). A synthetic blend of these ascarosides at physiologically relevant concentrations dispersed C. elegans dauer in the presence of food and also caused dispersion of IJs of S. feltiae and J2s of plant parasitic Meloidogyne spp. Assay guided fractionation revealed structural analogs as major active components of the S. feltiae (ascr#9) and C. elegans (ascr#2) dispersal blends. Further analysis revealed ascr#9 in all Steinernema spp. and Heterorhabditis spp. infected insect host cadavers. Conclusions/Significance Ascaroside blends represent evolutionarily conserved, fundamentally important communication systems for nematodes from diverse habitats, and thus may provide sustainable means for control of parasitic nematodes. PMID:22701701

  3. Community-acquired pneumonia.

    PubMed

    Falguera, M; Ramírez, M F

    2015-11-01

    This article not only reviews the essential aspects of community-acquired pneumonia for daily clinical practice, but also highlights the controversial issues and provides the newest available information. Community-acquired pneumonia is considered in a broad sense, without excluding certain variants that, in recent years, a number of authors have managed to delineate, such as healthcare-associated pneumonia. The latter form is nothing more than the same disease that affects more frail patients, with a greater number of risk factors, both sharing an overall common approach.

  4. Acquired hypofibrinogenemia: current perspectives

    PubMed Central

    Besser, Martin W; MacDonald, Stephen G

    2016-01-01

    Acquired hypofibrinogenemia is most frequently caused by hemodilution and consumption of clotting factors. The aggressive replacement of fibrinogen has become one of the core principles of modern management of massive hemorrhage. The best method for determining the patient’s fibrinogen level remains controversial, and particularly in acquired dysfibrinogenemia, could have major therapeutic implications depending on which quantification method is chosen. This review introduces the available laboratory and point-of-care methods and discusses the relative advantages and limitations. It also discusses current strategies for the correction of hypofibrinogenemia. PMID:27713652

  5. Embryological variation during nematode development.

    PubMed

    Schierenberg, Einhard

    2006-01-02

    Early cell lineages and arrangement of blastomeres in C. elegans are similar to the pattern found in Ascaris and other studied nematodes leading to the assumption that embryonic development shows little variation within the phylum Nematoda. However, analysis of a larger variety of species from various branches of the phylogenetic tree demonstrate that prominent variations in crucial steps of early embryogenesis exist among representatives of this taxon. So far, most of these variations have only been studied on a descriptive level and thus essentially nothing is known about their molecular or genetic basis. Nevertheless, it is obvious that the limited morphological diversity of the freshly hatched juvenile and the uniformity of the basic body plan contrast with the many modifications in the way a worm is generated from the egg cell. This chapter focuses on the initial phase between egg activation and gastrulation and deals with the following aspects: reproduction and diploidy, polarity, cleavage and germ line, cell lineages; cell cycles and maternal contribution, cell-cell communication and cell specification, gastrulation.

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

    PubMed

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

    2016-09-01

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

  7. Legionella-protozoa-nematode interactions in aquatic biofilms and influence of Mip on Caenorhabditis elegans colonization.

    PubMed

    Rasch, Janine; Krüger, Stefanie; Fontvieille, Dominique; Ünal, Can M; Michel, Rolf; Labrosse, Aurélie; Steinert, Michael

    2016-09-01

    Legionella pneumophila, the causative agent of Legionnaireś disease, is naturally found in aquatic habitats. The intracellular life cycle within protozoa pre-adapted the "accidental" human pathogen to also infect human professional phagocytes like alveolar macrophages. Previous studies employing the model organism Caenorhabditis elegans suggest that also nematodes might serve as a natural host for L. pneumophila. Here, we report for the first time from a natural co-habitation of L. pneumophila and environmental nematode species within biofilms of a warm water spring. In addition, we identified the protozoan species Oxytricha bifaria, Stylonychia mytilus, Ciliophrya sp. which have never been described as potential interaction partners of L. pneumophila before. Modeling and dissection of the Legionella-protozoa-nematode interaction revealed that C. elegans ruptures Legionella-infected amoebal cells and by this means incorporate the pathogen. Further infection studies revealed that the macrophage infectivity potentiator (Mip) protein of L. pneumophila, which is known to bind collagen IV during human lung infection, promotes the colonization of the intestinal tract of L4 larvae of C. elegans and negatively influences the life span of the worms. The Mip-negative L. pneumophila mutant exhibited a 32-fold reduced colonization rate of the nematodes after 48h when compared to the wild-type strain. Taken together, these studies suggest that nematodes may serve as natural hosts for L. pneumophila, promote their persistence and dissemination in the environment, and co-evolutionarily pre-adapt the pathogen for interactions with extracellular constituents of human lung tissue. Copyright © 2016 Elsevier GmbH. All rights reserved.

  8. Nematodes associated with blackberry in arkansas.

    PubMed

    Wehunt, E J; Golden, A M; Clark, J R; Kirkpatrick, T L; Baker, E C; Brown, M A

    1991-10-01

    A survey of the nematodes in blackberry (Rubus sp.) rhizospheres was conducted in Arkansas from 1986 to 1989. The state was divided arbitrarily into four quadrants. A total of 134 soil samples was collected, and 150-cm 3 subsamples were assayed for nematodes. Twenty-one species of plant-parasitic nematodes in 11 genera were extracted from the samples. There were differences (P = 0.05) among quadrants of the state in percentage occurrence of the nematodes and in population densities in samples. Xiphinema americanum, Helicotylenchus spp. (H. paraplatyurus, H. platyurus, and H. pseudorobustus), and Pratylenchus spp. (P. vulnus and P. zeae) were found in all quadrants. Xiphinema americanum population density was near 1,000 per 150 cm(3) soil in soil samples from two locations. Other nematodes found in one or more quadrants were Criconemella spp. (C. axeste, C. curvata, C. denoudeni, C. ornata, C. sphaerocephala, and C. xenoplax), Paratrichodorus minor, Tylenchorhynchus claytoni, Hirschmanniella oryzae, Hoplolaimus magnistylus, Scutellonema bradys, and undescribed species of Criconema, Tylenchulus, Xiphinema, and Meloidogyne. Criconemella sphaerocephala and Helicotylenchus platyurus are reported from Arkansas for the first time. Helicotylenchus paraplatyurus is reported from the United States for the first time.

  9. Molecular Transfer of Nematode Resistance Genes

    PubMed Central

    Williamson, V. M.; Ho, J.-Y.; Ma, H. M.

    1992-01-01

    Recombinant DNA techniques have been used to introduce agronomically valuable traits, including resistance to viruses, herbicides, and insects, into crop plants. Introduction of these genes into plants frequently involves Agrobacterium-mediated gene transfer. The potential exists for applying this technology to nematode control by introducing genes conferring resistance to nematodes. Transferred genes could include those encoding products detrimental to nematode development or reproduction as well as cloned host resistance genes. Host genes that confer resistance to cyst or root-knot nematode species have been identified in many plants. The best characterized is Mi, a gene that confers resistance to root-knot nematodes in tomato. A map-based cloning approach is being used to isolate the gene. For development of a detailed map of the region of the genome surrounding Mi, DNA markers genetically linked to Mi have been identified and analyzed in tomato lines that have undergone a recombination event near Mi. The molecular map will be used to identify DNA corresponding to Mi. We estimate that a clone of Mi will be obtained in 2-5 years. An exciting prospect is that introduction of this gene will confer resistance in plant species without currently available sources of resistance. PMID:19282989

  10. Effects of gastrointestinal nematode infection on the ruminant immune system.

    PubMed

    Gasbarre, L C

    1997-11-01

    Gastrointestinal (GI) nematodes of ruminants evoke a wide variety of immune responses in their hosts. In terms of specific immune responses directed against parasite antigens, the resulting immune responses may vary from those that give strong protection from reinfection after a relatively light exposure (e.g. Oesophagostomum radiatum) to responses that are very weak and delayed in their onset (e.g. Ostertagia ostertagi). The nature of these protective immune responses has been covered in another section of the workshop and the purpose of this section will be to explore the nature of changes that occur in the immune system of infected animals and to discuss the effect of GI nematode infections upon the overall immunoresponsiveness of the host. The discussion will focus primarily on Ostertagia ostertagi because this parasite has received the most attention in published studies. The interaction of Ostertagia and the host immune system presents what appears to be an interesting contradiction. Protective immunity directed against the parasite is slow to arise and when compared to some of the other GI nematodes, is relatively weak. Although responses that reduce egg output in the feces or increase the number of larvae undergoing inhibition may occur after a relatively brief exposure (3-4 months), immune responses which reduce the number of parasites that can establish in the host are not evident until the animal's second year. Additionally, even older animals that have spent several seasons on infected pastures will have low numbers of Ostertagia in their abomasa, indicating that sterilizing immune responses against the parasite are uncommon. In spite of this apparent lack of specific protective immune responses, infections with Ostertagia induce profound changes in the host immune system. These changes include a tremendous expansion of both the number of lymphocytes in the local lymph nodes and the number of lymphoid cells in the mucosa of the abomasum. This expansion

  11. Acquired Brain Injury Program.

    ERIC Educational Resources Information Center

    Schwartz, Stacey Hunter

    This paper reviews the Acquired Brain Injury (ABI) Program at Coastline Community College (California). The ABI Program is a two-year, for-credit educational curriculum designed to provide structured cognitive retraining for adults who have sustained an ABI due to traumatic (such as motor vehicle accident or fall) or non-traumatic(such as…

  12. Laboratory-acquired Brucellosis

    PubMed Central

    Gallo, Richard; Kelly, Molly; Limberger, Ronald J.; DeAngelis, Karen; Cain, Louise; Wallace, Barbara; Dumas, Nellie

    2004-01-01

    We report two laboratory-acquired Brucella melitensis infections that were shown to be epidemiologically related. Blood culture isolates were initially misidentified because of variable Gram stain results, which led to misdiagnoses and subsequent laboratory exposures. Notifying laboratory personnel who unknowingly processed cultures from brucellosis patients is an important preventive measure. PMID:15504276

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

    PubMed

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

    2013-11-01

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

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

    PubMed

    Webster, J M

    1980-10-01

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

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

    PubMed Central

    Webster, John M.

    1980-01-01

    A review of the development of entomophilic nematology and a commentary on the potential of entomophilic nematodes in controlling insect pests. The paper considers some of the major contributions to our knowledge of entomophilic nematology; factors involved in insect pest management and how they are applicable to the use of nematodes; nematodes which are most promising as biological control agents; and problems to be solved to facilitate the use of entomophilic nematodes in insect management. PMID:19300702

  16. The Power of Omics to Identify Plant Susceptibility Factors and to Study Resistance to Root-knot Nematodes.

    PubMed

    Cabrera, Javier; Barcala, Marta; Fenoll, Carmen; Escobar, Carolina

    2016-01-01

    Technology has contributed to the advances on the genomic, transcriptomic, metabolomic and proteomic analyses of the plant-root-knot nematode (RKN) interaction. Holistic approaches to obtain expression profiles, such as cDNA libraries, differential display, q-PCR, microarray hybridization, massive sequencing, etc., have increased our knowledge on the molecular aspects of the interaction and have triggered the development of biotechnological tools to control this plague. An important limitation, however, has been the difficulty of cross-comparative analysis of these data. The construction of a database, NEMATIC, compiling microarray data available in Arabidopsis of the interaction with plant endoparasitic nematodes facilitated the in silico analysis, but is not sufficient for the handling of 'omic' information of different plant species. Omics combined with cell isolation techniques have shed some light on the heterogeneous expression signatures of nematode induced gall tissues, i.e., plant defences are specifically inhibited in giant cells within the gall aiding the nematode for a successful establishment. The natural resistance against RKNs varies from an early hypersensitive reaction before the establishment of the nematode, to the arrest of gall growth. The molecular bases of these mechanisms, not fully understood yet, could disclose powerful targets for the development of biotechnology based tools for nematode control.

  17. The effect of the dominant polychaete Scolelepis squamata on nematode colonisation in sandy beach sediments: An experimental approach

    NASA Astrophysics Data System (ADS)

    Maria, Tatiana F.; Esteves, André M.; Vanaverbeke, Jan; Vanreusel, Ann

    2011-09-01

    The effect of an abundant sandy beach polychaete, Scolelepis squamata, on the colonisation of defaunated sediments by marine nematodes indicates that sandy beach fauna can be partially controlled by biological interactions within and across size groups. Experimental cores, equipped with windows allowing infaunal colonisation, were filled with defaunated sandy beach sediment containing two different treatments with and without S. squamata. These cores were inserted into microcosms filled with sediment with indigenous meiofauna collected from the field. The treatments were incubated in the laboratory at ambient temperature and salinity for 2, 7, 14 and 21 days, in order to follow the colonisation process of the defaunated sediments by the indigenous nematode fauna over time. Nematodes initially colonised both treatments, with abundances of up to 10% of the densities in the control; after 2 weeks, nematode densities in the cores without S. squamata surpassed the control densities. Nematode assemblages in both treatments were not species rich, and also differed in composition from the natural assemblages. The most successful colonising species, Enoplolaimus litoralis, was rare in the surrounding sediment, suggesting that colonisation was determined by species-specific characteristics such as body size, motility and feeding strategy. Initially the presence of macrofauna did not affect the nematode community composition, but after 2 weeks of the experiment, the presence of the polychaete seemed to facilitate the earlier establishment of non-opportunistic species.

  18. Effect of mine tailing on the spatial variability of soil nematodes from lead pollution in La Union (Spain).

    PubMed

    Rodríguez Martín, José Antonio; Gutiérrez, Carmen; Escuer, Miguel; García-González, Ma Teresa; Campos-Herrera, Raquel; Aguila, Nancy

    2014-03-01

    The Cartagena-La Union mining district, exploited since the end of the 3rd century BC, was one of the world's largest lead producers in the 19th century. Although activity ceased in 1991, today mining residues pose a huge pollution problem. This study characterises lead contents (total and DPTA) and other soil parameters (N, P, K, pH, SOM, CaCO3, granulometric fraction, etc.) using multivariate geostatistical methods in relation to nematode diversity. In this work, trophic groups and metabolic footprints of soil nematodes were measured using 193 samples from the mining, natural and agricultural areas in this district. We explored the relationship between soil health and nematode communities. High lead concentrations were quantified: mean 8,500 mg kg(-1) for total and 340 mg kg(-1) for DPTA in this mining area. Although nematode diversity was broad (81 taxa), their diversity, abundance and metabolic footprints significantly reduced in the mining area. Significant differences in the nematode community structure were observed, and the relative abundance of predators was sensitive to mine and agricultural activities, whilst omnivores reduced only in the agricultural area, and bacterial feeders exhibited a differential response to both anthropogenic disturbances. The total abundance of nematodes, trophic groups and c-p groups correlated negatively with soil Pb contents, and a positive relationship was found with SOM and N, P and K contents.

  19. Plant systemic induced responses mediate interactions between root parasitic nematodes and aboveground herbivorous insects

    PubMed Central

    Wondafrash, Mesfin; Van Dam, Nicole M.; Tytgat, Tom O. G.

    2013-01-01

    Insects and nematodes are the most diverse and abundant groups of multicellular animals feeding on plants on either side of the soil–air interface. Several herbivore-induced responses are systemic, and hence can influence the preference and performance of organisms in other plant organs. Recent studies show that plants mediate interactions between belowground plant parasitic nematodes (PPNs) and aboveground herbivorous insects. Based on the knowledge of plant responses to pathogens, we review the emerging insights on plant systemic responses against root-feeding nematodes and shoot-feeding insects. We discuss the potential mechanisms of plant-mediated indirect interactions between both groups of organisms and point to gaps in our knowledge. Root-feeding nematodes can positively or negatively affect shoot herbivorous insects, and vice versa. The outcomes of the interactions between these spatially separated herbivore communities appear to be influenced by the feeding strategy of the nematodes and the insects, as well as by host plant susceptibility to both herbivores. The potential mechanisms for these interactions include systemic induced plant defense, interference with the translocation and dynamics of locally induced secondary metabolites, and reallocation of plant nutritional reserves. During evolution, PPNs as well as herbivorous insects have acquired effectors that modify plant defense responses and resource allocation patterns to their advantage. However, it is also known that plants under herbivore attack change the allocation of their resources, e.g., for compensatory growth responses, which may affect the performance of other organisms feeding on the plant. Studying the chemical and molecular basis of these interactions will reveal the molecular mechanisms that are involved. Moreover, it will lead to a better understanding of the ecological relevance of aboveground–belowground interactions, as well as support the development of sustainable pest

  20. Nematode larvae infecting Priacanthus arenatus Cuvier, 1829 (Pisces: Teleostei) in Brazil.

    PubMed

    Kuraiem, Bianca P; Knoff, Marcelo; Felizardo, Nilza N; Gomes, Delir C; Clemente, Sérgio C São

    2016-05-31

    From July to December, 2013, thirty Priacanthus arenatus specimens commercialized in the cities of Niterói and Rio de Janeiro, State of Rio de Janeiro, were acquired. The fish were necropsied and filleted to investigate the presence of nematode larvae. Twenty fish (66.7%) out of the total were parasitized by nematode larvae. A total of 2024 larvae were collected; among them, 30 third-instar larvae of Anisakis sp. showed prevalence (P) = 20%, mean abundance (MA) = 1, and the mean intensity (MI) = 5, and infection sites (IS) = caecum, stomach, liver, and mesentery; and 1,994 third-instar larvae (1,757 encysted and 237 free) of Hysterothylacium deardorffoverstreetorum with P = 66.7%, MA = 66.5, and MI = 99.7, and IS = spleen, caecum, stomach, liver, mesentery, and abdominal muscle. This is the first study to report H. deardorffoverstreetorum and Anisakis sp. larvae parasitizing P. arenatus.

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

    USDA-ARS?s Scientific Manuscript database

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

  2. Site-Specific Detection and Management of Nematodes

    USDA-ARS?s Scientific Manuscript database

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

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

    USDA-ARS?s Scientific Manuscript database

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

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

    Treesearch

    L. David Dwinell

    1986-01-01

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

  5. Opportunity to use native nematodes for pest control

    USDA-ARS?s Scientific Manuscript database

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

  6. Towards a genome sequence for reniform nematode (Rotylenchulus reniformis)

    USDA-ARS?s Scientific Manuscript database

    Reniform nematode (Rotylenchulus reniformis) currently accounts for $130M in annual losses to the U.S. cotton industry and has supplanted root-knot nematode as the major nematode pest of cotton in Mississippi, Louisiana, and Alabama. Moreover, in other cotton-producing states the range and influenc...

  7. Nematode CLE signaling in Arabidopsis requires CLAVATA2 and CORYNE

    USDA-ARS?s Scientific Manuscript database

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

  8. A novel flavivirus in the soybean cyst nematode

    USDA-ARS?s Scientific Manuscript database

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

  9. Induction of systemic acquired resistance by Rotylenchulus reniformis and Meloidogyne incognita in cotton following separate and concomitant inoculations.

    USDA-ARS?s Scientific Manuscript database

    Systemic acquired resistance (SAR) can be elicited by virulent and avirulent pathogenic strains and SAR against plant-parasitic nematodes has been documented. Our objective was to determine whether co-infection of cotton by Meloidogyne incognita and Rotylenchulus reniformis affects the population le...

  10. Efficacy of an energy block containing Duddingtonia flagrans in the control of gastrointestinal nematodes of sheep.

    PubMed

    Sagüés, María F; Fusé, Luis A; Fernández, Alicia S; Iglesias, Lucía E; Moreno, Fabiana C; Saumell, Carlos A

    2011-09-01

    The efficacy of the nematode-trapping fungus Duddingtonia flagrans incorporated into an energy block was evaluated for the control of gastrointestinal nematodes in sheep. Four naturally parasitised sheep with average nematode egg counts of 2,470 eggs per gram grazed by pairs on two similar parasite-free paddocks for 30 days. During that period, one pair of sheep (treated animals, T1) received an energy block containing chlamydospores of D. flagrans at a dose of 200,000 chlamydopores/kg bw/day, while the second pair (control animals, C1) received a fungus-free energy block. The animals in both groups were taken off the paddocks after contaminating the pastures for a month with either nematode eggs plus fungal chlamydospores (T1) or nematode eggs alone (C1). Twelve parasite-free sheep were divided into two groups of six animals each, the treated group (T2) was placed on the paddock previously contaminated with parasites and fungus, while the control group (C2) was placed on the parasite-only paddock. These two groups grazed on their respective paddocks during 30 days and were then housed for 15 days, after which period they were slaughtered in order to determine the parasite burden present in each animal. Results showed that animals in group T2 harboured significantly less nematodes than their counterpart in group C2. The efficacy of D. flagrans was 92% against the total parasite burden, 100% against Haemonchus contortus and Teladorsagia circumcincta, 89.9% against Trichostrongylus colubriformis, 87.5% against Cooperia onchopora, and 90% against Trichostrongylus axei. No efficacy was detected against Nematodirus spathiger, Trichuris ovis and T. skrjabini.

  11. Combinatorial chemistry in nematodes: modular assembly of primary metabolism-derived building blocks

    PubMed Central

    2016-01-01

    The nematode Caenorhabditis elegans was the first animal to have its genome fully sequenced and has become an important model organism for biomedical research. However, like many other animal model systems, its metabolome remained largely uncharacterized, until recent investigations demonstrated the importance of small molecule-based signalling cascades for virtually every aspect of nematode biology. These studies have revealed that nematodes are amazingly skilled chemists: using simple building blocks from conserved primary metabolism and a strategy of modular assembly, C. elegans and other nematode species create complex molecular architectures to regulate their development and behaviour. These nematode-derived modular metabolites (NDMMs) are based on the dideoxysugars ascarylose or paratose, which serve as scaffolds for attachment of moieties from lipid, amino acid, carbohydrate, citrate, and nucleoside metabolism. Mutant screens and comparative metabolomics based on NMR spectroscopy and MS have so-far revealed several 100 different ascarylose (“ascarosides”) and a few paratose (“paratosides”) derivatives, many of which represent potent signalling molecules that can be active at femtomolar levels, regulating development, behaviour, body shape, and many other life history traits. NDMM biosynthesis appears to be carefully regulated as assembly of different modules proceeds with very high specificity. Preliminary biosynthetic studies have confirmed the primary metabolism origin of some NDMM building blocks, whereas the mechanisms that underlie their highly specific assembly are not understood. Considering their functions and biosynthetic origin, NDMMs represent a new class of natural products that cannot easily be classified as “primary” or “secondary”. We believe that the identification of new variants of primary metabolism-derived structures that serve important signalling functions in C. elegans and other nematodes provides a strong incentive for

  12. Diatom feeding across trophic guilds in tidal flat nematodes, and the importance of diatom cell size

    NASA Astrophysics Data System (ADS)

    Moens, Tom; Vafeiadou, Anna-Maria; De Geyter, Ellen; Vanormelingen, Pieter; Sabbe, Koen; De Troch, Marleen

    2014-09-01

    We examine the capacity of nematodes from three feeding types (deposit feeder, epistrate feeder, predator) to utilize microphytobenthos (MPB), and assess whether diatom cell size and consumer body size are important drivers of their feeding. We analyzed natural stable isotope ratios of carbon and nitrogen in abundant nematode genera and a variety of carbon sources at an estuarine intertidal flat. All nematodes had δ13C indicating that MPB is their major carbon source. δ15N, however, demonstrated that only one deposit and one epistrate feeder genus obtained most of their carbon from direct grazing on MPB, whereas other deposit feeders and predators obtained at least part of their carbon by predation on MPB grazers. We then performed a microcosm experiment in which equal cell numbers of each of three differently sized strains of the pennate diatom Seminavis were offered as food to four, one and one genera of deposit feeders, epistrate feeders and predators, respectively. Previous studies have shown that all but the epistrate feeder ingest whole diatoms, whereas the epistrate feeder pierces cells and sucks out their contents. Most genera showed markedly higher carbon absorption from medium and large cells than from small ones. When considering the number of cells consumed, however, none of the nematodes which ingest whole cells exhibited a clear preference for any specific diatom size. The epistrate feeder was the smallest nematode taxon considered here, yet it showed a marked preference for large cells. These results highlight that the feeding mechanism is much more important than consumer size as a driver of particle size selection in nematodes grazing MPB.

  13. Can parasites halt the invader? Mermithid nematodes parasitizing the yellow-legged Asian hornet in France.

    PubMed

    Villemant, Claire; Zuccon, Dario; Rome, Quentin; Muller, Franck; Poinar, George O; Justine, Jean-Lou

    2015-01-01

    Since its introduction in France 10 years ago, the yellow-legged Asian bee-hawking hornet Vespa velutina has rapidly spread to neighboring countries (Spain, Portugal, Belgium, Italy, and Germany), becoming a new threat to beekeeping activities. While introduced species often leave behind natural enemies from their original home, which benefits them in their new environment, they can also suffer local recruitment of natural enemies. Three mermithid parasitic subadults were obtained from V. velutina adults in 2012, from two French localities. However, these were the only parasitic nematodes reported up to now in Europe, in spite of the huge numbers of nests destroyed each year and the recent examination of 33,000 adult hornets. This suggests that the infection of V. velutina by these nematodes is exceptional. Morphological criteria assigned the specimens to the genus Pheromermis and molecular data (18S sequences) to the Mermithidae, due to the lack of Pheromermis spp. sequences in GenBank. The species is probably Pheromermis vesparum, a parasite of social wasps in Europe. This nematode is the second native enemy of Vespa velutina recorded in France, after a conopid fly whose larvae develop as internal parasitoids of adult wasps and bumblebees. In this paper, we provide arguments for the local origin of the nematode parasite and its limited impact on hornet colony survival. We also clarify why these parasites (mermithids and conopids) most likely could not hamper the hornet invasion nor be used in biological control programs against this invasive species.

  14. Can parasites halt the invader? Mermithid nematodes parasitizing the yellow-legged Asian hornet in France

    PubMed Central

    Zuccon, Dario; Rome, Quentin; Muller, Franck; Poinar Jr, George O.; Justine, Jean-Lou

    2015-01-01

    Since its introduction in France 10 years ago, the yellow-legged Asian bee-hawking hornet Vespa velutina has rapidly spread to neighboring countries (Spain, Portugal, Belgium, Italy, and Germany), becoming a new threat to beekeeping activities. While introduced species often leave behind natural enemies from their original home, which benefits them in their new environment, they can also suffer local recruitment of natural enemies. Three mermithid parasitic subadults were obtained from V. velutina adults in 2012, from two French localities. However, these were the only parasitic nematodes reported up to now in Europe, in spite of the huge numbers of nests destroyed each year and the recent examination of 33,000 adult hornets. This suggests that the infection of V. velutina by these nematodes is exceptional. Morphological criteria assigned the specimens to the genus Pheromermis and molecular data (18S sequences) to the Mermithidae, due to the lack of Pheromermis spp. sequences in GenBank. The species is probably Pheromermis vesparum, a parasite of social wasps in Europe. This nematode is the second native enemy of Vespa velutina recorded in France, after a conopid fly whose larvae develop as internal parasitoids of adult wasps and bumblebees. In this paper, we provide arguments for the local origin of the nematode parasite and its limited impact on hornet colony survival. We also clarify why these parasites (mermithids and conopids) most likely could not hamper the hornet invasion nor be used in biological control programs against this invasive species. PMID:26038716

  15. Doramectin efficacy against gastrointestinal nematodes in pigs.

    PubMed

    Stewart, T B; Fox, M C; Wiles, S E

    1996-11-01

    Four controlled trials with growing pigs were performed to determine efficacy of doramectin against natural and induced populations of nematodes. In Trial 1 (T1), 20 pigs with natural infections were assigned to one of two like groups on the basis of weight, sex and worm egg counts. In Trial 2 (T2), 20 pigs with negative worm egg counts were assigned to one of two groups on the basis of weight and sex. Each pig was subsequently given (per os) 3000 Trichuris suis embryonated eggs; 2000 Ascaris suum embryonated eggs; 10000 Oesophagostomum spp. infective larvae and 10,000 Strongyloides ransomi infective larvae (SC injection). In Trial 3 (T3), 20 pigs with negative worm egg counts were assigned as in T2, and each pig was subsequently given (per os) 2000 A. suum embryonated eggs, 15000 Oesophagostomum quadrispinulatum infective larvae, and 2891 Hyostrongylus rubidus infective larvae. In Trial 4 (T4), 16 pigs with negative worm egg counts were each assigned to one of two groups as in T2 and were given (per os) 2670 T. suis embryonated eggs. On Day 0 of each trial, each pig of the control group was injected IM in the neck with sterile saline at the rate of 1.5 ml 50 kg-1. Each pig in the treated group of each trial was similarly injected with doramectin at the rate of 300 micrograms kg-1. All pigs were necropsied 14 or 15 days post-treatment and parasites recovered by standard parasitological procedures. Efficacies against natural infections were: A. suum, 100%; Oesophagostomum spp. 100%; H. rubidus, 99.4%; and Strongyloides ransomi, 99.9%. Efficacies against induced infections were: 4th stage A. suum, 100%; 4th stage O.dentatum, 99.9%; 4th stage O.quadrispinulatum, 97.1 and 99.6%; 4th stage H. rubidus, 100%; adult S. ransomi, 100%; adult Trichuris suis in mixed infection, 54.1%; and in pure infection, 95.3%.

  16. Nematode Problems Affecting Agriculture in the Philippines

    PubMed Central

    Davide, R. G.

    1988-01-01

    Nematodes are considered major pests on most economic crops in the Philippines, particularly on banana, pineapple, citrus, tomato, ramie, and sugarcane. Radopholus similis is the most destructive nematode on banana, while Meloidogyne spp. are more serious on various vegetable crops such as tomato, okra, and celery and on fiber crops such as ramie. Tylenchulus semipenetrans is a problem on citrus and Rotylenchulus reniformis on pineapple and some legume crops. Hirschmanniella oryzae and Aphelenchoides besseyi are becoming serious on rice, and Pratylenchus zeae is affecting corn in some areas. Lately, Globodera rostochiensis has been causing serious damage on potato in the highlands. Control measures such as crop rotation, planting resistant varieties, chemical nematicide application, and biological control have been recommended to control these nematodes. PMID:19290204

  17. Remote Sensing of Parasitic Nematodes in Plants

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  18. Nematode problems affecting agriculture in the Philippines.

    PubMed

    Davide, R G

    1988-04-01

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

  19. Nematode taxonomy: from morphology to metabarcoding

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  20. Theory of the locomotion of nematodes

    PubMed Central

    Niebur, Ernst; Erdös, Paul

    1991-01-01

    We develop a model of the undulatory locomotion of nematodes, in particular that of Caenorhabditis elegans, based on mechanics. The model takes into account the most important forces acting on a moving worm and allows the computer simulation of a creeping nematode. These forces are produced by the interior pressure in the liquid-filled body cavity, the elasticity of the cuticle, the excitation of certain sets of muscles and the friction between the body and its support. We propose that muscle excitation patterns can be generated by stretch receptor control. By solving numerically the equations of motion of the model of the nematode, we demonstrate that these muscle excitation patterns are suitable for the propulsion of the animal. PMID:19431807

  1. Impact of eprinomectin on grazing behaviour and performance in dairy cattle with sub-clinical gastrointestinal nematode infections under continuous stocking management.

    PubMed

    Forbes, A B; Huckle, C A; Gibb, M J

    2004-11-10

    Forty spring-calving cows and heifers (20 of each) were allowed to acquire infection with gastrointestinal (GI) nematodes naturally during grazing. The control group (10 cows and 10 heifers) were compared with 20 similar animals treated with eprinomectin in order to evaluate the effect of GI nematodes on grazing behaviour, milk production, body condition score and live weight. The animals were paired according to parity and milk yield during the week prior to treatment, then within replicate pair randomly allocated to a different treatment group. The grazing area was sub-divided into 20 replicated paddocks of equivalent size and topography. Grazing pairs of either control or treated animals were randomly assigned to each paddock over the duration of the study (one pair per paddock). Grazing behaviour was recorded for both groups over a 10-day period commencing 4 days after treatment with eprinomectin. Milk yield was recorded daily and milk quality was recorded weekly. Live weight and body condition score were recorded on the day of allocation, the day of initial treatment and thereafter at weekly intervals until the end of the 4-week trial. Faecal samples were collected from each animal prior to, and after, allocation and submitted for counts of nematode eggs. Additional faecal samples were taken at the end of the study for culture and nematode identification. Individual faecal samples were also analysed for residual digestibility. Pasture samples for nematode larval counts were taken at the same time as faecal sampling. The parasitological results showed low levels of faecal nematode egg output throughout the study, with the heifers having higher counts than the cows. Faecal culture yielded species of Ostertagia, Cooperia, and Trichostrongylus. Pasture larval levels were very low throughout with no value exceeding 68 larvae/kg dry matter (DM) of herbage. There were significant (P < 0.05) effects of treatment on grazing time, eating time, total bites, total grazing

  2. Apoplastic Venom Allergen-like Proteins of Cyst Nematodes Modulate the Activation of Basal Plant Innate Immunity by Cell Surface Receptors

    PubMed Central

    Lozano-Torres, Jose L.; Wilbers, Ruud H. P.; Warmerdam, Sonja; Finkers-Tomczak, Anna; Diaz-Granados, Amalia; van Schaik, Casper C.; Helder, Johannes; Bakker, Jaap; Goverse, Aska; Schots, Arjen; Smant, Geert

    2014-01-01

    Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize

  3. Apoplastic venom allergen-like proteins of cyst nematodes modulate the activation of basal plant innate immunity by cell surface receptors.

    PubMed

    Lozano-Torres, Jose L; Wilbers, Ruud H P; Warmerdam, Sonja; Finkers-Tomczak, Anna; Diaz-Granados, Amalia; van Schaik, Casper C; Helder, Johannes; Bakker, Jaap; Goverse, Aska; Schots, Arjen; Smant, Geert

    2014-12-01

    Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize

  4. Resistance against gastrointestinal nematodes in Crioulo Lageano and crossbred Angus cattle in southern Brazil.

    PubMed

    Cardoso, Cristina P; Silva, Bruna F; Trinca, Luzia A; Amarante, Alessandro F T

    2013-02-18

    Gastrointestinal nematode (GIN) infection is a major cause of production losses in cattle. This study was carried out to evaluate the natural resistance against nematode infection in Crioulo Lageano and crossbred Angus male calves. Crioulo Lageano is a local cattle breed in the state of Santa Catarina, in southern Brazil. Ten weaned calves of each breed were grazed together on pasture and naturally infected with nematodes between July 2009 and December 2010. Once every 28 days, we collected fecal and blood samples for parasitological and immunological tests, as well as recording body weights. After 19 samplings, all animals were slaughtered for quantification and identification of GINs. We found that the animals had been infected with the following nematode species, in decreasing order by the mean number of specimens: Trichostrongylus axei, Cooperia punctata, Ostertagia ostertagi, Haemonchus placei, Oesophagostomum radiatum, and Trichuris spp. There were no significant differences between the Crioulo Lageano and crossbred Angus groups in terms of worm burden or nematode fecal egg count, nor in terms of the mean levels of immunoglobulin (G and A) against C. punctata and H. placei antigens, except in IgA mean level in abomasal mucus against H. placei adult worms that was significantly higher in crossbred Angus cattle (p<0.05). At the end of the study, the crossbred Angus cattle were heavier than were the Crioulo Lageano cattle (mean live weight, 507.35 and 390.3 kg, respectively). Comparative parasitological and immunological evaluation revealed no difference between two breeds in terms of their natural resistance against GINs.

  5. Interactions between nematodes and their microbial enemies in coastal sand dunes.

    PubMed

    Costa, Sofia R; Kerry, Brian R; Bardgett, Richard D; Davies, Keith G

    2012-12-01

    European foredunes are almost exclusively colonised by Ammophila arenaria, and both the natural succession and the die-out of this plant have been linked to populations of plant-parasitic nematodes (PPN). The overarching aim of this study was to investigate top-down control processes of PPN in these natural ecosystems through comparative analyses of the diversity and dynamics of PPN and their microbial enemies. Our specific aims were, first, to identify and quantify PPN microbial enemies in European sand dunes; second, to assess their life history traits, their spatial and temporal variation in these ecosystems, and third, to evaluate their control potential of PPN populations. This was done by seasonal sampling of a range of sites and making observations on both the nematode and the microbial enemy communities in rhizosphere sand. Nine different nematode microbial enemies belonging to different functional groups were detected in European sand dunes. Their high diversity in these low productivity ecosystems could both result from or lead to the lack of dominance of a particular nematode genus. The distribution of microbial enemies was spatially and temporally variable, both among and within sampling sites. Obligate parasites, either with low host-specificity or having the ability to form an environmentally resistant propagule, are favoured in these ecosystems and are more frequent and abundant than facultative parasites. Three microbial enemies correlated, either positively or negatively, with PPN population size: Catenaria spp., Hirsutella rhossiliensis and Pasteuria penetrans. Microbial-enemy supported links in the food-web may be involved in the control of PPN populations through indirect effects. The endospore-forming P. penetrans was the most successful top-down control agent, and was implicated in the direct control of Meloidogyne spp. and indirect facilitation of Pratylenchus spp. Overall, our findings suggest strong and diverse top-down control effects on

  6. Immunological control of gastrointestinal nematode infections.

    PubMed

    Klei, T R

    1997-11-01

    Control of nematode parasitism by an active manipulation of the host immune response has been a goal of veterinary and medical parasitologists for decades. The reality of achieving this goal has been questioned vigorously and demonstrations of the feasibility of using immunological control under field conditions are minimal. Nevertheless, with the rapid growth of modern biotechnology and the identification of novel parasite molecules as vaccine targets, the potential for success in this area has recently generated considerable excitement. The induction and regulation of the ruminant immune response against nematode parasites can be controlled either by management programs which include anthelmintic treatment or by vaccination. Both approaches will be discussed in this session.

  7. Detecting Nematode Features from Digital Images

    PubMed Central

    de la Blanca, N. Pérez; Fdez-Valdivia, J.; Castillo, P.; Gómez-Barcina, A.

    1992-01-01

    Procedures for estimating and calibrating nematode features from digitial images are described and evaluated by illustration and mathematical formulae. Technical problems, such as capturing and cleaning raw images, standardizing the grey level range of images, and the detection of characteristics of the body habitus, presence or absence of stylet knobs, and tail and lip region shape are discussed. This study is the first of a series aimed at developing a set of automated methods to permit more rapid, objective characterizations of nematode features than is achievable by cumbersome conventional methods. PMID:19282998

  8. Delayed response to ring nematode (Mesocriconema xenoplax) feeding on grape roots linked to vine carbohydrate reserves and nematode feeding pressure

    USDA-ARS?s Scientific Manuscript database

    The chronic impact of ring nematode (Mesocriconema xenoplax) feeding on grapevine (Vitis vinifera) was studied under controlled conditions. 'Pinot noir' grapevines were exposed to ring nematode or kept nematode-free for three growing seasons, and vines were either grown in full sunlight, 15% of full...

  9. Desmosomes in acquired disease.

    PubMed

    Stahley, Sara N; Kowalczyk, Andrew P

    2015-06-01

    Desmosomes are cell-cell junctions that mediate adhesion and couple the intermediate filament cytoskeleton to sites of cell-cell contact. This architectural arrangement integrates adhesion and cytoskeletal elements of adjacent cells. The importance of this robust adhesion system is evident in numerous human diseases, both inherited and acquired, which occur when desmosome function is compromised. This review focuses on autoimmune and infectious diseases that impair desmosome function. In addition, we discuss emerging evidence that desmosomal genes are often misregulated in cancer. The emphasis of our discussion is placed on the way in which human diseases can inform our understanding of basic desmosome biology and in turn, the means by which fundamental advances in the cell biology of desmosomes might lead to new treatments for acquired diseases of the desmosome.

  10. Desmosomes in acquired disease

    PubMed Central

    Stahley, Sara N.; Kowalczyk, Andrew P.

    2015-01-01

    Desmosomes are cell-cell junctions that mediate adhesion and couple the intermediate filament cytoskeleton to sites of cell-cell contact. This architectural arrangement functions to integrate adhesion and cytoskeletal elements of adjacent cells. The importance of this robust adhesion system is evident in numerous human diseases, both inherited and acquired, that occur when desmosome function is compromised. This review focuses on autoimmune and infectious diseases that impair desmosome function. In addition, we discuss emerging evidence that desmosomal genes are often misregulated in cancer. The emphasis of our discussion is placed on how human diseases inform our understanding of basic desmosome biology, and in turn, how fundamental advances in the cell biology of desmosomes may lead to new treatments for acquired diseases of the desmosome. PMID:25795143

  11. Hospital-acquired thrombocytopenia.

    PubMed

    McMahon, Christine M; Cuker, Adam

    2014-10-01

    The development of thrombocytopenia is common in hospitalized patients and is associated with increased mortality. Frequent and important causes of thrombocytopenia in hospitalized patients include etiologies related to the underlying illness for which the patient is admitted, such as infection and disseminated intravascular coagulation, and iatrogenic etiologies such as drug-induced immune thrombocytopenia, heparin-induced thrombocytopenia, posttransfusion purpura, hemodilution, major surgery, and extracorporeal circuitry. This review presents a brief discussion of the pathophysiology, distinguishing clinical features, and management of these etiologies, and provides a diagnostic approach to hospital-acquired thrombocytopenia that considers the timing and severity of the platelet count fall, the presence of hemorrhage or thrombosis, the clinical context, and the peripheral blood smear. This approach may offer guidance to clinicians in distinguishing among the various causes of hospital-acquired thrombocytopenia and providing management appropriate to the etiology.

  12. Naturally Acquired Antibody Responses to Plasmodium vivax and Plasmodium falciparum Merozoite Surface Protein 1 (MSP1) C-Terminal 19 kDa Domains in an Area of Unstable Malaria Transmission in Southeast Asia.

    PubMed

    Wang, Qinghui; Zhao, Zhenjun; Zhang, Xuexing; Li, Xuelian; Zhu, Min; Li, Peipei; Yang, Zhaoqing; Wang, Ying; Yan, Guiyun; Shang, Hong; Cao, Yaming; Fan, Qi; Cui, Liwang

    2016-01-01

    Understanding naturally acquired immunity to infections caused by Plasmodia in different malaria endemicity settings is needed for better vaccine designs and for exploring antibody responses as a proxy marker of malaria transmission intensity. This study investigated the sero-epidemiology of malaria along the international border between China and Myanmar, where malaria elimination action plans are in place. This study recruited 233 P. vivax and 156 P. falciparum infected subjects with acute malaria at the malaria clinics and hospitals. In addition, 93 and 67 healthy individuals from the same endemic region or from non-endemic region, respectively, were used as controls. Acute malaria infections were identified by microscopy. Anti-recombinant PfMSP119 and PvMSP119 antibody levels were measured by ELISA. Antibody responses to respective MSP119 were detected in 50.9% and 78.2% patients with acute P. vivax and P. falciparum infections, respectively. There were cross-reacting antibodies in Plasmodium patients against these two recombinant proteins, though we could not exclude the possibility of submicroscopic mixed-species infections. IgG1, IgG3 and IgG4 were the major subclasses. Interestingly, 43.2% of the healthy endemic population also had antibodies against PfMSP119, whereas only 3.9% of this population had antibodies against PvMSP119. Higher antibody levels were correlated with age and parasite density, but not with season, gender or malaria history. Both total IgG and individual IgG subclasses underwent substantial declines during the convalescent period in three months. This study demonstrated that individuals in a hypoendemic area with coexistence of P. vivax and P. falciparum can mount rapid antibody responses against both PfMSP119 and PvMSP119. The significantly higher proportion of responders to PfMSP119 in the healthy endemic population indicates higher prevalence of P. falciparum in the recent past. Specific antibodies against PvMSP119 could serve as a

  13. Naturally Acquired Antibody Responses to Plasmodium vivax and Plasmodium falciparum Merozoite Surface Protein 1 (MSP1) C-Terminal 19 kDa Domains in an Area of Unstable Malaria Transmission in Southeast Asia

    PubMed Central

    Wang, Qinghui; Zhao, Zhenjun; Zhang, Xuexing; Li, Xuelian; Zhu, Min; Li, Peipei; Yang, Zhaoqing; Wang, Ying; Yan, Guiyun; Shang, Hong; Cao, Yaming; Fan, Qi; Cui, Liwang

    2016-01-01

    Understanding naturally acquired immunity to infections caused by Plasmodia in different malaria endemicity settings is needed for better vaccine designs and for exploring antibody responses as a proxy marker of malaria transmission intensity. This study investigated the sero-epidemiology of malaria along the international border between China and Myanmar, where malaria elimination action plans are in place. This study recruited 233 P. vivax and 156 P. falciparum infected subjects with acute malaria at the malaria clinics and hospitals. In addition, 93 and 67 healthy individuals from the same endemic region or from non-endemic region, respectively, were used as controls. Acute malaria infections were identified by microscopy. Anti-recombinant PfMSP119 and PvMSP119 antibody levels were measured by ELISA. Antibody responses to respective MSP119 were detected in 50.9% and 78.2% patients with acute P. vivax and P. falciparum infections, respectively. There were cross-reacting antibodies in Plasmodium patients against these two recombinant proteins, though we could not exclude the possibility of submicroscopic mixed-species infections. IgG1, IgG3 and IgG4 were the major subclasses. Interestingly, 43.2% of the healthy endemic population also had antibodies against PfMSP119, whereas only 3.9% of this population had antibodies against PvMSP119. Higher antibody levels were correlated with age and parasite density, but not with season, gender or malaria history. Both total IgG and individual IgG subclasses underwent substantial declines during the convalescent period in three months. This study demonstrated that individuals in a hypoendemic area with coexistence of P. vivax and P. falciparum can mount rapid antibody responses against both PfMSP119 and PvMSP119. The significantly higher proportion of responders to PfMSP119 in the healthy endemic population indicates higher prevalence of P. falciparum in the recent past. Specific antibodies against PvMSP119 could serve as a

  14. [Soil nematode as a bioindicator of environment pollution].

    PubMed

    Zhang, Wei; Song, Yufang; Sun, Tieheng; Song, Xueying; Zhou, Qixing

    2004-10-01

    As a part of mesofauna in soil ecosystem, nematode plays an important role in essential soil processes. Because of its unique attributes, nematode was widely used in the study of soil health indication. Based on the current studies at home and abroad, this paper discussed the function and application of nematode in indicating and diagnosing soil pollution, and the indices (maturity index, diversity index, similarity index, key species, N/C ratio, and physiological index) and their characteristics of nematode communities used as indicators. As a useful index of bioindicators in ecotoxicological diagnosis, the prospect of soil nematode application was of potential.

  15. Mining nematode genome data for novel drug targets.

    PubMed

    Foster, Jeremy M; Zhang, Yinhua; Kumar, Sanjay; Carlow, Clotilde K S

    2005-03-01

    Expressed sequence tag projects have currently produced over 400 000 partial gene sequences from more than 30 nematode species and the full genomic sequences of selected nematodes are being determined. In addition, functional analyses in the model nematode Caenorhabditis elegans have addressed the role of almost all genes predicted by the genome sequence. This recent explosion in the amount of available nematode DNA sequences, coupled with new gene function data, provides an unprecedented opportunity to identify pre-validated drug targets through efficient mining of nematode genomic databases. This article describes the various information sources available and strategies that can expedite this process.

  16. The evolution of spliced leader trans-splicing in nematodes.

    PubMed

    Pettitt, Jonathan; Harrison, Neale; Stansfield, Ian; Connolly, Bernadette; Müller, Berndt

    2010-08-01

    Spliced leader trans-splicing occurs in many primitive eukaryotes including nematodes. Most of our knowledge of trans-splicing in nematodes stems from the model organism Caenorhabditis elegans and relatives, and from work with Ascaris. Our investigation of spliced leader trans-splicing in distantly related Dorylaimia nematodes indicates that spliced-leader trans-splicing arose before the nematode phylum and suggests that the spliced leader RNA gene complements in extant nematodes have evolved from a common ancestor with a diverse set of spliced leader RNA genes.

  17. Genetically engineered bananas resistant to Xanthomonas wilt disease and nematodes.

    PubMed

    Tripathi, Leena; Atkinson, Howard; Roderick, Hugh; Kubiriba, Jerome; Tripathi, Jaindra N

    2017-05-01

    Banana is an important staple food crop feeding more than 100 million Africans, but is subject to severe productivity constraints due to a range of pests and diseases. Banana Xanthomonas wilt caused by Xanthomonas campestris pv. musacearum is capable of entirely destroying a plantation while nematodes can cause losses up to 50% and increase susceptibility to other pests and diseases. Development of improved varieties of banana is fundamental in order to tackle these challenges. However, the sterile nature of the crop and the lack of resistance in Musa germplasm make improvement by traditional breeding techniques either impossible or extremely slow. Recent developments using genetic engineering have begun to address these problems. Transgenic banana expressing sweet pepper Hrap and Pflp genes have demonstrated complete resistance against X. campestris pv. musacearum in the field. Transgenic plantains expressing a cysteine proteinase inhibitors and/or synthetic peptide showed enhanced resistance to a mixed species population of nematodes in the field. Here, we review the genetic engineering technologies which have potential to improve agriculture and food security in Africa.

  18. Handmade Cloned Transgenic Piglets Expressing the Nematode Fat-1 Gene

    PubMed Central

    Zhang, Peng; Zhang, Yidi; Dou, Hongwei; Yin, Jingdong; Chen, Yu; Pang, Xinzhi; Vajta, Gabor; Bolund, Lars

    2012-01-01

    Abstract Production of transgenic animals via somatic cell nuclear transfer (SCNT) has been adapted worldwide, but this application is somewhat limited by its relatively low efficiency. In this study, we used handmade cloning (HMC) established previously to produce transgenic pigs that express the functional nematode fat-1 gene. Codon-optimized mfat-1 was inserted into eukaryotic expression vectors, which were transferred into primary swine donor cells. Reverse transcriptase PCR (RT-PCR), gas chromatography, and chromosome analyses were performed to select donor clones capable of converting n-6 into n-3 fatty acids. Blastocysts derived from the clones that lowered the n-6/n-3 ratio to approximately 1:1 were transferred surgically into the uteri of recipients for transgenic piglets. By HMC, 37% (n=558) of reconstructed embryos developed to the blastocyst stage after 7 days of culture in vitro, with an average cell number of 81±36 (n=14). Three recipients became pregnant after 408 day-6 blastocysts were transferred into four naturally cycling females, and a total of 14 live offspring were produced. The nematode mfat-1 effectively lowered the n-6/n-3 ratio in muscle and major organs of the transgenic pig. Our results will help to establish a reliable procedure and an efficient option in the production of transgenic animals. PMID:22686479