Thalassomyxa australis rhythmicity V. synchronization by light-dark-cycles depends on temperature and food organism
Titel:
Thalassomyxa australis rhythmicity V. synchronization by light-dark-cycles depends on temperature and food organism
Auteur:
Landsbeck, Brigitta Engelmann, Wolfgang
Verschenen in:
Biological rhythm research
Paginering:
Jaargang 22 (1991) nr. 3 pagina's 213-221
Jaar:
1991-09
Inhoud:
Silyn-Roberts (1988) reported that synchronization of Thalassomyxa australis by light-dark-cycles (LD) occurred when Dunaliella was used as a food organism, whereas the use of Amphiprora as a food organism lead to freerunning rhythmic changes between active and resting phases in this marine rhizopod. We have found, however, that synchronization to LD cycles also depends on ambient temperature and can occur with Amphiprora as a food organism at higher temperatures (19.5°C) than used by Silyn-Roberts (18.5°C). At lower temperatures (16.5°C) both, Amphiprora - and Dunaliella-fed Thalassomyxa australis cannot be synchronized by the LD-cycle. The difference in synchronization of Thalassomyxa australis in connection with the two food organisms is restricted to a small temperature range between 17.3 and 19.2°C. Under freerunning conditions the period length of Am-phiprora-fed Thalassomyxa australis depends more strongly on temperature than that of Dunaliella-fed cultures. Period length of Dunaliella-fed amoeba increases less at lower temperatures than Amphiprora-fed animals. Therefore a 12: 12 h LD cycle can synchronize Dunaliella-fed cultures at a lower temperature, because the freerun period is still within the range of entrainment, which is not the case in Amphiprora-fed cultures. This is an interesting situation, where the period length of an unusual circadian rhythm is not only affected by temperature, but also by the kind of food. The factors for these effects are unknown.
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