Effect of light exposure on circadian rhythm in theront excystment in Cryptocaryon irritans.

Autor: Kotake M; The University of Tokyo, Graduate School of Agricultural and Life Sciences, Tokyo, Japan., Watanabe Y; The University of Tokyo, Graduate School of Agricultural and Life Sciences, Tokyo, Japan., Itoh N; The University of Tokyo, Graduate School of Agricultural and Life Sciences, Tokyo, Japan., Yoshinaga T; The University of Tokyo, Graduate School of Agricultural and Life Sciences, Tokyo, Japan. Electronic address: yoshinaga-tomoyshi@g.ecc.u-tokyo.ac.jp.
Jazyk: angličtina
Zdroj: Parasitology international [Parasitol Int] 2024 Feb; Vol. 98, pp. 102812. Date of Electronic Publication: 2023 Sep 28.
DOI: 10.1016/j.parint.2023.102812
Abstrakt: We examined the effects of light exposure on the theront excystment circadian rhythm in Cryptocaryon irritans using a newly invented apparatus, which enabled us to examine the excystment rhythms of theronts from tomonts with low labor. Using the apparatus, we examined the timings of theront excystment from tomonts exposed directly to light and from tomonts exposed to light-exposed seawater by counting the number of excysted theronts. We found that the theront excystment time changed only when tomonts were directly exposed to light, indicating that light reception is essential for circadian rhythm entrainment. When tomonts were exposed to light only once for 12 h, either on Day 1, Day 2, or Day 3 after leaving host and being encysted, the circadian rhythm was entrained according to the photoperiod given on tomonts. Tomonts exposed to a low light (1 lx) with 12L:12D photoperiod daily showed a circadian rhythm similar to that in tomonts exposed to an intense light (500 lx) under the same photoperiod. When tomonts were incubated at 22 °C, 25 °C, or 28 °C under the same photoperiod, almost the same circadian rhythm was developed, suggesting temperature has little effect on the circadian rhythm entrainment between the range, even though the date of excystment was delayed in lower temperatures. These results suggest the circadian rhythm of theront excystment can be entrained in tomonts on the seabed of inner bays where net-cage aquaculture is conducted, and be involved in the outbreaks of cryptocaryoniasis there.
Competing Interests: Declaration of Competing Interest Declaration of generative AI and AI-assisted technologies in the writing process. During the preparation of this work the authors used Chat GPT in order to edit the manuscript. After using this tool, the authors reviewed and edited the content as needed and take full responsibility for the content of the publication.
(Copyright © 2023. Published by Elsevier B.V.)
Databáze: MEDLINE
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