Waterborne and Surface-Associated Carbohydrates as Settlement Cues for Larvae of the Specialist Marine Herbivore Alderia modesta

摘要: Larvae of the specialist marine herbivore AIde na modesta (Opisthobranchia: Ascoglossa) metamorphose in response to a chemical settlement cue from alga Vaucheria Iongicaulis, obligate adult prey. Bioactivity coeluted with both high and low molecular weight carbo hydrates solution, insoluble carbohydrates associated algal cell wall. metamorphosedin water conditioned by V. longicaulis, as well frozen homogenized tissue. Tl@einducer was efficiently extracted algae boiling water, but after all soluble activity cx tracted, residual tissue still induced larval settlement. Etha nol precipitation boiled-water extract followed gel filtration. chromatography showed that precipitate con Wined >100,000 Da weight, while supernatant contained only (<2,000 Da); cases carbohydrate peak. An aqueous-insolu ble 4% NaOH chromatographedin 7 M urea yield bioactive Activity not affected proteinase K or mild acid hydrolysis, significantly decreased periodate treatment. The results indicate larvae A. water-soluble sur face-assOciated exists