Evidence for a circaseptan and a circasemiseptan growth response to light/dark cycle shifts in nucleated and enucleated Acetabularia cells, respectively.

Abstract

Nucleated as well as enucleated Acetabularia mediterranea cells were subjected to 14 different patterns of shifts in a regimen of 12 hr of light alternating with 12 hr of darkness in four 30-day long experiments. With one exception, which might be due to a circannual modulation, these experiments showed that nucleated cells had maximal growth rates when a shift was performed every 7th or 15th day. In enucleated cells, maxima were observed on shift schedules that were about 3-4 days rather than about 7 days apart. The results indicate that in the unicellular green alga Acetabularia a rhythm of about 7 days (circaseptan) exists and that removal of the nucleus results in a circaseptan frequency multiplication.

Circaseptan Rhythms of Semen Characteristics of a Brazilian Breed (“Mangalarga”) Stallion

“…As to their ubiquity, spontaneous as well as reactive circasemiseptans (3.5-day) and circaseptans characterize the genetically anchored time structures (Halberg et al, 1965;Cornélissen and Halberg, 1992) of physiologic and psychologic variables (Hildebrandt et al, 1982;Cornélissen et al, 1993). About-7-day patterns are found at different levels of organization of different biological systems (Cutkomp et al, 1984;Halberg et al, 1985 and1986;Schweiger et al, 1986;Han et al, 1991). Circaseptan patterns are found in single cells (Schweiger et al, 1986;Han et al, 1991), insects (Hayes et al, 1986;Marques, M.D.…”

Prokaryotic and eukaryotic unicellular chronomics

“…The then-fashionable, overly conservative power spectra were accompanied by a periodogram with results obvious to the naked eye of those who take the time to look up original publications rather than relying on hear-say. To their credit, the symposium's organizers there after extended their focus time-microscopically to about 7-day (circaseptan) variation, documenting their open mind [20][21][22] and we are grateful to both of them, with one of them becoming a very close associate in research [11,[21][22][23][24][25][26]] as well as a close personal friend.…”

Solar activity and human health at middle and low geomagnetic latitudes in Central America

“…There is evidence of the presence of multiples or submultiples of the circaseptan rhythms known as multiseptan rhythms reported at various levels of life: at the unicellular level, Schweiger et al (1986) showed that Acetabularie Mediterrane growth responded in a circaseptan and a circasemiseptan manner to shifts of light and darkness, according to the presence or removal of their nuclei respectively. This implies that the genetic code of an organism that has been living in our planet since millions of years might be programmed to modulate circaseptan growth frequencies.…”