| Title | Calcium ion dependency and the role of inositol phosphates in melatonin-induced encystment of dinoflagellates |
| Creator | |
| Date Issued | 1997-06-01 |
| Source Publication | Journal of Cell Science
 |
| ISSN | 0021-9533 |
| Volume | 110Issue:12Pages:1387-1393 |
| Abstract | The unicellular eukaryotic dinoflagellates shed their flagella and form a new pellicle cyst wall in response to environmental stress, This encystment process can also be induced by indoleamines such as melatonin and 5-methoxytryptamine. To decipher the complex signaling events which lead to encystment, we have investigated the functional roles of Ca and inositol phosphates in indoleamine-induced encystment of the dinoflagellates Alexandrium catenella and Crypthecodinium cohnii. Pretreatment with EGTA, but not with EDTA, effectively blocked the indoleamine-induced encystment of A. catenella in a dose-dependent manner. Conversely, agents that facilitate the influx of Ca (Bay K 8644, A23187 and ionomycin) dose-dependently induced encystment of A. catenella. Endoplasmic Ca-ATPase inhibitors such as thapsigargin and the peptide toxin melittin also induced encystment of A. catenella. These results suggest that an elevation of intracellular [Ca] may be involved in the encystment response. In terms of the regulation of phospholipase C, melatonin dose- and time-dependently stimulated the formation of inositol phosphates in C. cohnii. The rank order of potency for several indoleamines to stimulate inositol phosphates formation was 2-iodomelatonin > 5-methoxytryptamine ≤ melatonin >> N-acetylserotonin > 5-hydroxytryptamine. This rank order was the same as for the indoleamine-induced encystment of C. cohnii as previously reported. Our results indicate that indoleamine-induced activation of phospholipase C and elevation of intracellular [Ca] may be proximal steps in the signal transduction pathway leading to encystment in dinoflagellates. Moreover, this is the first demonstration of the possible involvement of Ca and inositol phosphates as second messengers in dinoflagellates. |
| Keyword | 5-Methoxytryptamine Calcium Dinoflagellate Encystment Inositol phosphate Melatonin |
| URL | View source |
| Language | 英语English |
| Scopus ID | 2-s2.0-0030855744 |
| Citation statistics | |
| Document Type | Journal article |
| Identifier | http://repository.uic.edu.cn/handle/39GCC9TT/11706 |
| Collection | Research outside affiliated institution |
| Corresponding Author | Wong，Yung H. |
| Affiliation | 1.Department of Biology,Hong Kong University of Science and Technology,Kowloon,Clear Water Bay,Hong Kong 2.Biotechnology Research Institute,Hong Kong University of Science and Technology,Kowloon,Clear Water Bay,Hong Kong |
| Recommended Citation GB/T 7714 | Tsim，Siu Tai,Wong，Joseph T.Y.,Wong，Yung H. Calcium ion dependency and the role of inositol phosphates in melatonin-induced encystment of dinoflagellates[J]. Journal of Cell Science, 1997, 110(12): 1387-1393. |
| APA | Tsim，Siu Tai, Wong，Joseph T.Y., & Wong，Yung H. (1997). Calcium ion dependency and the role of inositol phosphates in melatonin-induced encystment of dinoflagellates. Journal of Cell Science, 110(12), 1387-1393. |
| MLA | Tsim，Siu Tai,et al."Calcium ion dependency and the role of inositol phosphates in melatonin-induced encystment of dinoflagellates". Journal of Cell Science 110.12(1997): 1387-1393. |
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