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Interspecific nematode signals regulate dispersal behavior.

Kaplan F, Alborn HT, von Reuss SH, Ajredini R, Ali JG, Akyazi F, Stelinski LL, Edison AS, Schroeder FC, Teal PE - PLoS ONE (2012)

Bottom Line: Assay guided fractionation revealed structural analogs as major active components of the S. feltiae (ascr#9) and C. elegans (ascr#2) dispersal blends.Further analysis revealed ascr#9 in all Steinernema spp. and Heterorhabditis spp. infected insect host cadavers.Ascaroside blends represent evolutionarily conserved, fundamentally important communication systems for nematodes from diverse habitats, and thus may provide sustainable means for control of parasitic nematodes.

View Article: PubMed Central - PubMed

Affiliation: Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture (USDA-ARS), Gainesville, Florida, United States of America. fkaplan@ufl.edu

ABSTRACT

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.

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Related in: MedlinePlus

Activity guided fractionation of the S. feltiae dispersal pheromone.(A) Reverse phase (C18) chromatography of insect cadaver extract. The image represents two independent experiments. The estimated physiologically relevant concentration was used in the assays; Frc, fraction. (B) Testing physiologically relevant concentration of ascarosides found in Frc A (ascr#9, 40.3 pmol/µl and ascr#11, 1.3 pmol/µl). Image represents three experiments. (C) Ascr#2 and ascr#9 are structural analogs. Natural and synthetic ascr#9 were tested in combination with fraction B and C. Image represents four experiments. (D) Structure of ascr#11. It (1.3 pmol/µl) is also sufficient to cause dispersal in combination with fractions B and C. Image represents three experiments.
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pone-0038735-g004: Activity guided fractionation of the S. feltiae dispersal pheromone.(A) Reverse phase (C18) chromatography of insect cadaver extract. The image represents two independent experiments. The estimated physiologically relevant concentration was used in the assays; Frc, fraction. (B) Testing physiologically relevant concentration of ascarosides found in Frc A (ascr#9, 40.3 pmol/µl and ascr#11, 1.3 pmol/µl). Image represents three experiments. (C) Ascr#2 and ascr#9 are structural analogs. Natural and synthetic ascr#9 were tested in combination with fraction B and C. Image represents four experiments. (D) Structure of ascr#11. It (1.3 pmol/µl) is also sufficient to cause dispersal in combination with fractions B and C. Image represents three experiments.

Mentions: For characterization of the S. feltiae dispersal pheromone, insect host cadavers were extracted with 70% EtOH, fractionated by reverse phase (C18) chromatography and assayed (Fig 4A, B, C, and D). The bioassay revealed that a combination of all three fractions (A, B, and C) was necessary for activity (Fig 4A). Analysis of the fractions by LC-MS (Fig S2) revealed 2 ascarosides in fraction A, which were identified as ascr#9 and ascr#11 with the help of synthetic standard [15], [21]. Bioassays showed that ascr#9 and ascr#11 did not have activity by themselves at physiologically relevant concentrations (Fig 4B). This was expected because the natural fraction A was inactive when tested alone (Fig 4A). However, combining synthetic asc#9 at the biologically relevant concentration (40 pmol/µl) with natural fractions B and C, restored the original dispersal activity (Fig 4C), confirming ascr#9 as an active component of the S. feltiae dispersal blend. The second ascaroside found in fraction A, asc#11 also restored the full activity when combined with fraction B and C (Fig 4D), indicating that either, ascr#9 or ascr#11, by themselves are sufficient to reconstitute full dispersal activity in combination with fractions B and C.


Interspecific nematode signals regulate dispersal behavior.

Kaplan F, Alborn HT, von Reuss SH, Ajredini R, Ali JG, Akyazi F, Stelinski LL, Edison AS, Schroeder FC, Teal PE - PLoS ONE (2012)

Activity guided fractionation of the S. feltiae dispersal pheromone.(A) Reverse phase (C18) chromatography of insect cadaver extract. The image represents two independent experiments. The estimated physiologically relevant concentration was used in the assays; Frc, fraction. (B) Testing physiologically relevant concentration of ascarosides found in Frc A (ascr#9, 40.3 pmol/µl and ascr#11, 1.3 pmol/µl). Image represents three experiments. (C) Ascr#2 and ascr#9 are structural analogs. Natural and synthetic ascr#9 were tested in combination with fraction B and C. Image represents four experiments. (D) Structure of ascr#11. It (1.3 pmol/µl) is also sufficient to cause dispersal in combination with fractions B and C. Image represents three experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368880&req=5

pone-0038735-g004: Activity guided fractionation of the S. feltiae dispersal pheromone.(A) Reverse phase (C18) chromatography of insect cadaver extract. The image represents two independent experiments. The estimated physiologically relevant concentration was used in the assays; Frc, fraction. (B) Testing physiologically relevant concentration of ascarosides found in Frc A (ascr#9, 40.3 pmol/µl and ascr#11, 1.3 pmol/µl). Image represents three experiments. (C) Ascr#2 and ascr#9 are structural analogs. Natural and synthetic ascr#9 were tested in combination with fraction B and C. Image represents four experiments. (D) Structure of ascr#11. It (1.3 pmol/µl) is also sufficient to cause dispersal in combination with fractions B and C. Image represents three experiments.
Mentions: For characterization of the S. feltiae dispersal pheromone, insect host cadavers were extracted with 70% EtOH, fractionated by reverse phase (C18) chromatography and assayed (Fig 4A, B, C, and D). The bioassay revealed that a combination of all three fractions (A, B, and C) was necessary for activity (Fig 4A). Analysis of the fractions by LC-MS (Fig S2) revealed 2 ascarosides in fraction A, which were identified as ascr#9 and ascr#11 with the help of synthetic standard [15], [21]. Bioassays showed that ascr#9 and ascr#11 did not have activity by themselves at physiologically relevant concentrations (Fig 4B). This was expected because the natural fraction A was inactive when tested alone (Fig 4A). However, combining synthetic asc#9 at the biologically relevant concentration (40 pmol/µl) with natural fractions B and C, restored the original dispersal activity (Fig 4C), confirming ascr#9 as an active component of the S. feltiae dispersal blend. The second ascaroside found in fraction A, asc#11 also restored the full activity when combined with fraction B and C (Fig 4D), indicating that either, ascr#9 or ascr#11, by themselves are sufficient to reconstitute full dispersal activity in combination with fractions B and C.

Bottom Line: Assay guided fractionation revealed structural analogs as major active components of the S. feltiae (ascr#9) and C. elegans (ascr#2) dispersal blends.Further analysis revealed ascr#9 in all Steinernema spp. and Heterorhabditis spp. infected insect host cadavers.Ascaroside blends represent evolutionarily conserved, fundamentally important communication systems for nematodes from diverse habitats, and thus may provide sustainable means for control of parasitic nematodes.

View Article: PubMed Central - PubMed

Affiliation: Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture (USDA-ARS), Gainesville, Florida, United States of America. fkaplan@ufl.edu

ABSTRACT

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.

Show MeSH
Related in: MedlinePlus