Chemotactic behaviour of Strongyloides stercoralis infective larvae on a sodium chloride gradient.
Chemotactic responses of Strongyloides stercoralis infective larvae (L3) to sodium chloride (NaCl) were investigated by recording larval tracks on a saline gradient in agarose. On agarose, larvae migrated randomly, whereas when placed at 0.01 m NaCl larvae moved to approximately 1.1 m NaCl where they turned, headed down the gradient and eventually remained circling at a favoured salinity (0.03-0.07 m). Conversely, when placed at 2.85 m NaCl, the L3 larvae moved unidirectionally to lower, more favoured salt concentrations. Here they circled, changing directions frequently while making 'loop-like' tracks. Larvae were immobilized within 5 min at salt concentrations exceeding 3 m NaCl. When placed at 0.01 m NaCl, 51.1% +/- 26.9 migrated to 1.1 m NaCl after 2 min, and 80% +/- 18.7 did so after 8 min, at an average velocity of 4.1 +/- 1.4 mm/min. Larvae (53.6% +/- 21.6) were repelled from 2.85 m NaCl to lower concentrations after 2 min. After 8 min, 95% +/- 11.1 were repelled, moving at an average velocity of 6.2 +/- 1.1 mm/min. Using this bioassay, the influence of neuronal control over chemotactic behaviour of S. stercoralis and other parasitic nematodes can be elucidated.
Forbes
W M
WM
Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104, USA.
Ashton
F T
FT
Boston
R
R
Schad
G A
GA
D000818:Animals; D001681:Biological Assay; D002633:Chemotaxis / Q000187:drug effects*; D007814:Larva / Q000187:drug effects* / Q000502:physiology; D008124:Locomotion / Q000187:drug effects / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology*; D017171:Strongyloides stercoralis / Q000187:drug effects* / Q000502:physiology
D012965:Sodium Chloride