. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 140 G. D. GIBSON AND CHIA LLJ • H. vesicula |BO- G Melanochlam<< £2 A/deria - «60- D Onch, n 9- 0 40- CO § Crr :iea = 1 ^ = f 20- 0- \ " 1 1 'z i Metamorphic Inducer Figure 4. Specificity of egg mass jelly (EMJ) activity to Haminaea callidegenita. Data are the percentage of metamorphosis in veligers of five mollusc species (identified in the legend) in response to seawater (SW), EMJ, a methanol jelly extract, 19 mmol K\ and a natural substrate associated with metamorphosis in that species (identified in text
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 140 G. D. GIBSON AND CHIA LLJ • H. vesicula |BO- G Melanochlam<< £2 A/deria - «60- D Onch, n 9- 0 40- CO § Crr :iea = 1 ^ = f 20- 0- \ " 1 1 'z i Metamorphic Inducer Figure 4. Specificity of egg mass jelly (EMJ) activity to Haminaea callidegenita. Data are the percentage of metamorphosis in veligers of five mollusc species (identified in the legend) in response to seawater (SW), EMJ, a methanol jelly extract, 19 mmol K\ and a natural substrate associated with metamorphosis in that species (identified in text). callidegenita veligers was a polar (methanol- and water- soluble) compound that was smaller than 1000 Da in mo- lecular weight, non-proteinaceous, and stable to temper- ature (-60° to 100°C) and acid. It is interesting that ve- ligers of all three opisthobranchs metamorphose in re- sponse to inducers that are small, non-proteinaceous, water-soluble compounds; however, further comparisons are not possible until these inducers have been identified. Under field conditions, metamorphic cues that are water soluble may become highly dilute within a short distance from the inducer source (Hadfield and Scheuer. 1985). Dilution of the EMJ inducer would presumably not be a problem as the compound need only diffuse through the egg mass to be effective (less than a few millimeters). Active inducer is present in jelly throughout the 2-week encap- sulated period (the period from oviposition to hatching), suggesting that it is not released as the gelatinous matrix degrades during hatching. It is possible that the inducer is bound to a nonsoluble component of the egg mass (such as the matrix) or if it diffuses from the egg mass, it is present in large enough quantities to allow expected rates of metamorphosis. The metamorphic inducer found in egg mass jelly ap- pears to be derived from the parent, because methanol extracts of adult tissue contain a functionally similar compound. This
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
