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ISOLATION OF A SULFOQUINOVOSYL MONOACYLGLYCEROL FROM BRYOPSIS SP. (CHLOROPHYTA): IDENTIFICATION OF A FACTOR CAUSING A POSSIBLE SPECIES‐SPECIFIC ECDYSIS RESPONSE IN GAMBIERDISCUS TOXICUS (DINOPHYCEAE) 1,
Author(s) -
Sakamoto Bryan,
Hokama Yoshitsugi,
Horgen F. David,
Scheuer Paul J.,
Kan Yukiko,
Nagai Hiroshi
Publication year - 2000
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1046/j.1529-8817.2000.00006.x
Subject(s) - ecdysis , dinophyceae , biology , chlorophyta , botany , algae , moulting , ecology , phytoplankton , larva , nutrient
A bioactive compound that induced ecdysis (thecal loss) in Gambierdiscus toxicus Adachi et Fukuyo (Dinophyceae) cultures was isolated from a host macroalga, Bryopsis sp. (Chlorophyta). The ecdysis factor was identified by spectroscopic methods as 1‐ O ‐palmitoyl‐3‐ O ‐(6′‐sulfo‐α‐ d ‐quinovopyranosyl)‐ sn ‐glycerol (PSQG). From our results, PSQG induced ecdysis at a high frequency and appeared not to inhibit the growth of G. toxicus cultures. The induction of ecdysis followed a dose‐dependent saturation curve from 4 to 8 μM PSQG. To determine specificity of PSQG, the effects of palmitoyl‐ l ‐α‐lysophosphatidylcholine (PLPC) were observed. Because PLPC contains a lipophilic palmitoyl moiety and hydrophilic phosphatidyl choline group, the compound possesses a detergent‐like amphiphathic property similar to PSQG. Our results demonstrate that PLPC induced ecdysis at a high frequency in G. toxicus cultures and generated a similar dose–response curve as PSQG. The ecdysis activity observed in PSQG and PLPC may correlate with the detergent‐like amphiphathic property of both compounds. Although PLPC induced a similar ecdysis response as PSQG, PLPC appeared to inhibit the growth of G. toxicus cultures. Preliminary results on the effects of PSQG on the dinoflagellates Prorocentrum lima (Ehrenberg) Dodge and Coolia monotis Meunier did not parallel the results observed in G. toxicus. This study demonstrated the existence of a factor from Bryopsis sp. that elicited a possible species‐specific ecdysis response in G. toxicus cultures. This is the first report of a compound that induced ecdysis in G. toxicus or in any dinoflagellate.