Autoregulation of the total number of cells in culture

According to the universally accepted concept of the development of life on the Earth, multicellular organisms initially emerged as a result of either the union of identical unicellular organisms with the following functional differentiation, or the union of symbionts, in which there already was a certain simple functional separation. However, in either case the progenitors of multicellular organisms were ensembles, communities of unicellular organisms. For a certain number of unicellular organisms to be treated as an ensemble, there must be some interconnection between its members. Colonies of mechanically connected unicellular organisms were a later, more advanced stage; here, unicellular organisms living separately are considered. Such interconnection must, in particular, limit from above the total numbers of the members of the ensemble, because an excessive increase in these numbers could disturb the connections between members of the ensemble to the extent of its destruction. In addition, too large numbers of members in the ensemble could lead to nutrient depletion in its habitat. One can assume that such interconnection between unicellular organisms was evolutionarily developed and genetically fixed. I assumed that modern unicellular organisms retain such an ability to regulate their total numbers. The validity of this assumption was tested in experiments, whose results are presented in this paper.