title: Proteomic analysis of the entomopathogenic nematode Steinernema feltiae IS-6 IJs under evaporative and osmotic stresses.
abstract: In order to improve the storage capability under desiccation of the widely sold biological insecticides based on entomopathogenic nematodes (EPNs), we need to understand how these organisms respond to desiccation stress. As part of our studies to achieve this, we studied survival and protein expression in infective juveniles of the EPN Steinernema feltiae IS-6 when exposed to evaporative (exposure to 97% relative humidity (RH) for 3 days, followed by a 1-day exposure to 85% RH) and osmotic (exposure to 24% glycerol for 8h) stresses. More than 400 protein spots that were detected by proteomic analysis showed reproducible abundance within replications. Of these, 10 spots and 7 spots showed detectable changes in abundance under evaporative and osmotic stress, respectively, compared to fully hydrated nematodes. Three spots exhibited a differential response pattern between evaporative and osmotic desiccation (one was down regulated and two were novel in evaporative desiccation). Peptide mass mapping with MALDI-TOF mass spectrometry (MS) identified 10 desiccation-response proteins, among which several are known to be stress responsive including heat shock protein 60, coenzyme q biosynthesis protein, inositol monophosphatase and fumarate lyase that were found in both stresses. Other identified proteins are known to be involved in the cell cycle regulation, regulation of gene transcription, organization of macromolecular structure and some currently have no known functions. Our results suggest that it is unlikely that improvement of desiccation tolerance in EPNs can be achieved through genetic transformation and addition of single genes and that selective breeding could be the best approach to generate desiccation resistant worms.
authors.affiliation: Department of Food Science, ARO, The Volcani Center, Bet-Dagan, Israel. songbichen@yahoo.com
authors.forename: Songbi
authors.initials: S
authors.lastname: Chen
authors.forename: Itamar
authors.initials: I
authors.lastname: Glazer
authors.forename: Natan
authors.initials: N
authors.lastname: Gollop
authors.forename: Phil
authors.initials: P
authors.lastname: Cash
authors.forename: Evelyn
authors.initials: E
authors.lastname: Argo
authors.forename: Audrey
authors.initials: A
authors.lastname: Innes
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Stewart
authors.forename: Ian
authors.initials: I
authors.lastname: Davidson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Wilson
mesh_terms: D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D000818:Animals; D018834:Chaperonin 60 / Q000032:analysis; D015180:Electrophoresis, Gel, Two-Dimensional; D015801:Helminth Proteins / Q000032:analysis*; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis; D020543:Proteome / Q000032:analysis*; D017168:Rhabditida / Q000737:chemistry* / Q000502:physiology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D018834:Chaperonin 60; D015801:Helminth Proteins; D020543:Proteome; D010744:Phosphoric Monoester Hydrolases; C021822:myo-inositol-1 (or 4)-monophosphatase