Circadian communication between unicells?

Abstract

Populations of Gonyaulax polyedra, in two different phases, about 11 h apart, were mixed, and the intensity of their spontaneous bioluminescence glow recorded for about 2 wk under conditions of constant dim (35 +/- 3 microE/m2/s) white light and constant temperature (19.0 +/- 0.3 degrees C). The phases and amplitudes of glow signals recorded from mixed cultures were compared with those obtained from the arithmetic sum of the intensity data from two control vials. Peaks in control cultures generally remained separate, but there was a spontaneous increase in the period beginning 6-11 d after the onset of constant conditions. This did not occur in cultures in which the medium was exchanged with fresh medium every 2 d. In the actual mixes of two cultures there was a merging of the two subpeaks in the signal, which did not occur when the medium was exchanged. The results indicate that conditioning of the medium by cells may affect the period of the circadian rhythm and that this might result in a type of communication.

Algae Know the Time of Day: Circadian and Photoperiodic Programs

“…This is not idle speculation: the intercellular signaling of Dictyostelium by secretion of cAMP is famous, and there is an example of a molecule made by an alga that affects the period of its circadian clock—the molecule is “gonyauline” from Lingulodinium (Roenneberg et al 1991). Moreover, there is evidence in Lingulodinium that suggests a weak coupling of the circadian rhythms among cells in a population (Broda et al 1985).…”

Isolated fungal cellulose terminal domains and a synthetic minimum analogue bind to cellulose

“…Here, we present data on the functional (cellulose-binding) properties of (i) the B-A-region from the main cellulase CBH 1 from T. reesei, (ii) the B-A-region from the corresponding and strongly homologous [14,15] enzyme from Sporotrichum pulverulentum and (iii) a synthetic 'minimum' A-region of Tr CBH1.…”

A temperature-compensated ultradian clock ticks in Schizosaccharomyces pombe

“…At that time the authors interpreted the observed damping as evidence against intercellular communication. A later study employing mixing experiments questioned that view (Broda et al, 1986). The pattern in mixed cultures differed from the calculated sum of the two control cultures.…”