Encystment of Gonyaulax polyedra: Dependence on Light
| Autor: | Ivonne Balzer |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
photoperiodism
endocrine system medicine.medical_specialty biology Physiology biology.organism_classification Melatonin Pineal gland Endocrinology medicine.anatomical_structure Physiology (medical) Internal medicine Botany Darkness medicine Gonyaulax Circadian rhythm hormones hormone substitutes and hormone antagonists Ecology Evolution Behavior and Systematics medicine.drug |
| Zdroj: | Biological Rhythm Research. 27:386-389 |
| ISSN: | 1744-4179 0929-1016 |
| DOI: | 10.1076/brhm.27.3.386.12961 |
| Popis: | The unicellular alga Gonyaulax polyedra reacts to short days and low temperatures by forming asexual cysts. Its photoperiodic response is elicited via the physiological mediation of melatonin. This indoleamine known as a dark signal in vertebrates is also synthetised by this dinophyt attaining concentrations as high as in the mammalian pineal gland. Its level varies in a circadian fashion, showing a steep increase after the onset of darkness, followed by a gradual decline towards the beginning of photophase. The critical photoperiod of the encystment response shows in Gonyaulax polyedra the remarkably high precision of about half an hour. Under otherwise non-inducing conditions, a single addition of 10 –4 M melatonin, given 1 h before the onset of darkness, elicits encystment as much, and with similar kinetics, as in short-days. The effect of melatonin action during long-day conditions (11:13) and low temperature (15°C) has been investigated. After addition of 10 –4 M or 7x10 –5 M melatonin each 3 h, the ... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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