On Some Physiological Aspects in the Daily Rhythmic Activity of the Sea-Pen, Cavernularia Obesa Valenciennes

Imafuku, Michio

doi:10.5134/175766

Cited by 4 publications

(5 citation statements)

References 23 publications

(28 reference statements)

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“…Experiments undertaken to determine if there exists any daily rhythmicity in muscle or bioluminescence activities of the colony yielded negative results (Anctil et al, 1991 and personal observations). A daily rhythmic activity has previously been reported in a sea pen related to the sea pansy (Imafuku, 1973), but not in another (Dickinson, 1978). Thus, although the presence of daily rhythmicity in the sea pansy cannot be ruled out, the photocycle does not seem to be involved in coordinating any of its major activities.…”

Section: Discussionmentioning

confidence: 81%

Melatonin in a primitive metazoan: Seasonal changes of levels and immunohistochemical visualization in neurons

Mechawar

Anctil

1997

J. Comp. Neurol.

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Monthly day/night melatonin activity profiles were determined by radioimmunoassay over a 13-month period in the colonial anthozoan Renilla köllikeri, and no daily rhythmic oscillation was found. Averaging those monthly values yielded a seasonal quantitative rhythm in both colonial and non-colonial tissues of this cnidarian, with spring and summer levels found to be four to five times higher than autumn and winter ones. The annual rise, which occurred in two successive Aprils, coincided with the first stages of sexual maturation in R. köllikeri. Immunohistochemistry with a melatonin antibody raised in sheep revealed an exclusively neuronal distribution of melatonin-immunoreactivity (MEL-IR) in the endodermal septal filaments wrapped around gametophores, in endodermal walls of the rachis, and in the ectoderm of polyps. The MEL-IR ectodermal neurons shared many morphological features with serotonin-immunoreactive (5-HT-IR) neurons previously described in this animal but showed either weak or absent 5-HT-IR in double-labelling experiments. In contrast, MEL-IR and 5-HT-IR were strongly colocalized in endodermal neurons. These results indicate that melatonin is not a daily photoperiodic messenger but may instead act as a seasonal marker for reproduction in this cnidarian. We also provide the first evidence of a neuronal localisation of melatonin in an invertebrate, which suggests that melatonin may act as a neurotransmitter or neurohormone in the least evolved animals endowed with a nervous system.

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Section: Discussionmentioning

confidence: 81%

Melatonin in a primitive metazoan: Seasonal changes of levels and immunohistochemical visualization in neurons

Mechawar

Anctil

1997

J. Comp. Neurol.

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“…8) that the rhythm of about 24 hours will persist as long as 6 days in the constant dim light and is also temperature-compensated, as in various animals and plants (Sweeney and Hastings, 1960;Imafuku, 1973), in the temperature range of 20-30° C, in which the normal activity is observed (Fig. 3).…”

Section: Control Factors Of Activitymentioning

confidence: 95%

On the Nocturnal Behavior of Tylos Granulatus Miers (Crustacea : Isopoda)

Imafuku¹

1976

Publ. SMBL

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The physiological and ecological aspects of the nocturnal activity of Tylos granulatus was investigated by natural observations and laboratory experiments that brought about the following results:1. Tylos granulatus inhabits the pebbly beach, in the part higher than the level of respective high water, especially richly under stranded matters. It is nocturnal, gathering on the stranded materials at night but hiding itself in spaces among pebbles in the daytime.2. On the studied beach, the temperature is higher in the daytime than at night, sometimes over 35°C in the daytime but below 30°C at night in the summer season. The humidity is higher at night. As the temperature of the hiding space is rather mild even in the daytime as compared with that of the exterior, Tylos can keep itself in the mild circumstances throughout the day by its nocturnal behavior.3. Tylos is photopositive to lower light and can survive more than 2 days under the exposure to a bright light of ca. 10000 lux in the moist state. Its normal activity is displayed in the temperature range of20 to 30°C and the critical temperature is found at about 45°C in the moist state. It survives longer in the highly humid condition and will be killed in 2 hours when it is exposed to the natural daytime condition on the beach in summer, though it can survive more than 4.5 hours if watered.4. The activity rhythm of Tylos is controlled by the cycle of light, temperature and humidity and follows either of any two cycle according to the applied temperatures, when they are given coordinately with each other.These results seem to explain the nocturnal activity of Tylos as an adaptation to the terrestrial life in relation to water conservation. Lastly, some speculation is made as to the development of the nocturnal activity of this animal on the above-mentioned explanation and the results of observations in the field and the laboratory.

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“…This shows clearly that the change of hydrogen ion concentration is really effective for inducing expansion (Mori, 1960). (5) The phase of the rhythm can be shifted by the injection of carbonated acidic seawater, which was clearly demonstrated by Imafuku (1973). When the carbonated seawater is injected into contracted sea-pens that have been cultured in constant dim light, they respond to the injection and expand as mentioned in the preceding sections.…”

Section: General Sketch Of the Metabolic Theory For Maintaining Thmentioning

confidence: 85%

“…According to the author's experiments (Mori, 1945a(Mori, , 1960, C0 2 content, ammonia content and hydrogen ion concentration of body fluid, glycogen content of body tissue and 0 2 consumption of the animal, all these metabolic states show rhythmic changes in the course of a day. Usually the metabolic rate is dependent on the environmental temperature, and indeed Imafuku ( 1973) clarified that 0 2 consumption rate of the sea-pen is within the usual range of Q 10 (2.53).…”

Section: Difficulties To the Author's Metabolic Theorymentioning

confidence: 99%

“…(2) The author (Mori, 1945b), as well as Imafuku (1973), observed rhythmic activities of unusual manner; namely, some colonies showed two expansion states a night, while some others showed complete omission of an expansion state during a whole day. In some cases where an expansion state was omitted, the period of expansion of the following expansion lasted for 48 hours (i.e., twice a circadian period and not such as intermediate 30 or 36 hours).…”

Section: Difficulties To the Author's Metabolic Theorymentioning

confidence: 99%

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Daily Rhythmic Activity of the Sea-pen Cavernularia obesa Valenciennes. XIX. Further Considerations on the Mechanism of the Circadian Rhythmic Activity

Mori¹

1994

Publ. SMBL

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A general description of circadian rhythm of the sea-pen is given. The mechanism which supposedly maintains this circadian rhythm is explained. The periodic change ofhydrogen ion concentration of body fluid which occurs with expansion and contraction of the animal is proposed as the mechanism which maintains the circadian rhythm of the sea-pen. This idea may be a kind of metabolic theory. Some difficulties for this theory are examined, and, despite these difficulties, the reality of the metabolic theory is again emphasized and the reasons for supporting this theory are explained. Some other considerations on the circadian rhythm of the sea-pen are also presented and the recent literature which seems to support the metabolic theory is reviewed.

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On Some Physiological Aspects in the Daily Rhythmic Activity of the Sea-Pen, Cavernularia Obesa Valenciennes

Cited by 4 publications

References 23 publications

Melatonin in a primitive metazoan: Seasonal changes of levels and immunohistochemical visualization in neurons

Melatonin in a primitive metazoan: Seasonal changes of levels and immunohistochemical visualization in neurons

On the Nocturnal Behavior of Tylos Granulatus Miers (Crustacea : Isopoda)

Daily Rhythmic Activity of the Sea-pen Cavernularia obesa Valenciennes. XIX. Further Considerations on the Mechanism of the Circadian Rhythmic Activity

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