title: Influence of potassium ion and osomtic pressure on development of Haemonchus contortus in vitro.
abstract: Development of infective larvae of Haemonchus contortus to the fourth stage in vitro was impaired if the concentration of potassium ion in the medium was 0.26 mM or less. At or below 0.015 mM, development was almost completely stopped. High concentrations of potassium, in solutions with a ratio of sodium to potassium from 150 down to 1.3, were all equally favorable for development, but solutions composed only of salts of potassium were unfavorable. Development was impaired by osmotic pressures below 200 mosm/kg or above 350 mosm/kg and ecdysis was arrested by high but not by low osmotic pressures.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D003470:Culture Media; D006189:Haemonchus / Q000187:drug effects / Q000254:growth & development*; D008274:Magnesium / Q000494:pharmacology; D009997:Osmotic Pressure; D011188:Potassium / Q000494:pharmacology*; D012964:Sodium / Q000494:pharmacology; D014251:Trichostrongyloidea / Q000254:growth & development*
chemical_list: D003470:Culture Media; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium