title: External stimuli and intracellular signalling in the modification of the nematode surface during transition to the mammalian host environment.
abstract: Previous work has shown that the surface of infective larvae of parasitic nematodes will not bind the fluorescent lipid analogue 5-N-(octadecanoyl)aminofluorescein (AF18) until after exposure of the parasite to mammalian tissue-culture conditions. In this study, culture media which are permissive or non-permissive for the acquisition of lipophilicity for AF18 were altered in order to examine possible stimuli involved. This showed that external alkaline pH and high sodium ion concentration were highly stimulatory. The internal signalling pathways which may be involved in the surface alteration were then examined using agents which are known to affect intracellular signalling in mammalian cells. The results indicated that elevation of cGMP levels was stimulatory whereas inhibition of a putative Na+/H+ antiporter or calcium mobilization was inhibitory, and it is argued that high intracellular levels of cAMP may be inhibitory. Whilst the precise effects of the agents used on nematode cells remain to be established, these results provide a framework for the examination of the processes involved in the modification of the nematode surface which takes place immediately after the infection event.
authors.affiliation: Department of Biochemistry, University of Glasgow, UK.
authors.forename: L
authors.initials: L
authors.lastname: Proudfoot
authors.forename: J R
authors.initials: JR
authors.lastname: Kusel
authors.forename: H V
authors.initials: HV
authors.lastname: Smith
authors.forename: M W
authors.initials: MW
authors.lastname: Kennedy
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000330:Aedes / Q000469:parasitology; D000818:Animals; D002009:Brugia / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology; D000001:Calcimycin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D004153:Dipetalonema / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007814:Larva; D008322:Mammals; D009348:Nematoda / Q000472:pathogenicity* / Q000502:physiology*; D009529:Nicardipine / Q000494:pharmacology; D009559:Nippostrongylus / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology; D009599:Nitroprusside / Q000494:pharmacology; D047428:Protein Kinase Inhibitors; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D014234:Trichinella / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology
chemical_list: D047428:Protein Kinase Inhibitors; D013449:Sulfonamides; D009599:Nitroprusside; C016276:8-bromocyclic GMP; D000001:Calcimycin; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; C017967:W 7; C034700:N-(6-aminohexyl)-1-naphthalenesulfonamide; D009529:Nicardipine; D000242:Cyclic AMP; D006152:Cyclic GMP; D015056:1-Methyl-3-isobutylxanthine