Decreasing period-length of the endogenous circadian rhythm of oxygen evolution in Acetabularia and its possible relation to aging.
Endogenous circadian rhythms observed under constant conditions normally show period length variations. However, a general trend is difficult to identify when cells or organisms are entrained with the usual 24-h-period light/dark cycles. Therefore, these variations in time have been considered as fluctuations. In order to gain more insight into this phenomenon, individual Acetabularia cells were exposed to light/dark cycles of 16 h (LD 8:8) and 33.6 h (LD 16.8:16.8), respectively, i.e., periods which lie distinctly outside the range of the normal circadian entrainment. Employing a high-resolution procedure for data analysis, decreasing period lengths could consistently be detected when cells were kept under constant conditions for several weeks. Possible causes of this decrease are discussed.
von Lindern
L
L
Max-Planck-Institut für Zellbiologie, Ladenburg, Germany.
Berger
S
S
D000076:Acetabularia / Q000378:metabolism*; D002940:Circadian Rhythm; D003624:Darkness; D008027:Light; D010100:Oxygen / Q000378:metabolism*; D013997:Time Factors
D010100:Oxygen