Cell Thermoregulation: Problems, Advances and Perspectives

Abstract

Thermoregulation at organism level is the well-established fact. The question on possibility of thermoregulation at the cell level remains opened. Based on study of distribution of chromosomal heterochromatin regions (HRs) in various human populations, in norm and at some forms of pathology the hypothesis about thermoregulation existence at the cell level has been presented. The essence of hypothesis of cell thermoregulation (СТ) is elimination of the temperature difference between the nucleus and cytoplasm when the nucleus temperature becomes higher than the cytoplasm temperature. The nucleus, in contrast to the cytoplasm, cannot conduct heat directly in the extracellular space, from where the heat is taken by the circulating flow of sap, lymph and blood. Thus, the nucleus can conduct heat only in the cytoplasm. With this, the nucleus has two options for the dissipation of heat surplus: either by increasing its volume or increasing the heat conductivity of the nuclear envelope. As the first option is limited, and the second one is hampered because of thickness of the cell membranes, apparently the higher eukaryotes took advantage of the opportunity of a dense layer of peripheral condensed chromatin (CC) as heat conductor for a more efficient elimination of the temperature difference between the nucleus and cytoplasm. The СС localized between a nucleus and cytoplasm is made of different types of chromosomal HRs. For this reason, СС is subject to wide variability in population. Obviously, the density of the СС packing depends on the type and quantity of chromosomal HRs in its structure that can affect upon its heat-conducting ability. If the situation is this then we are entitled to expect a new type of variability with all consequences resulting from here.

From 48 to 46 Chromosomes: Origin of Modern Man

“…In this case, the merging of two pairs of ancestral acrocentrics allowed: а) to birth the individuals with different, including the low, number of Q-HRs; b) the populations gradually to eliminate two pairs of acrocentrics with a particularly high frequency of Q-HRs. Just the latter circumstance prevented the birth in the population of individuals with different, and especially with a low number of chromosomal Q-HRs, which, as we believe, is better adapted to harsher ecological conditions of the environment (Ibraimov, 1993(Ibraimov, , 2010(Ibraimov, , 2011(Ibraimov, , 2017.…”

“…7, No. 1;2017 HRs in a population with 48 chromosomes. But, they were eliminated by the natural selection because of their poor adaptability to the hot climate where our common chimps and gorilla ancestors lived.…”

“…Perhaps, just at this stage in the life history of our ancestors, the evolutionary changes appeared in the genome, which, ultimately, resulted to the emergence of the modern human. In particular, the individuals with a number of chromosomal Q-HRs in the genome closest to the modern Africans became adapted better in the new climate conditions (see Ibraimov, 1993Ibraimov, , 2010Ibraimov, , 2011Ibraimov, , 2015Ibraimov, , 2017.…”

“…7, No. 1;2017 varying proportions (that is, the most is 1 and less of all the 100 dollar bills), then the number of possible combinations at cash transactions be virtually unlimited.…”

“…Therefore, it is highly likely that this chromosome rearrangement in the karyotype of the common ancestor ultimately, contributed, to the appearance of the modern man. As it allowed the appearance in the population of individuals with different number of chromosomal Q-HRs in the genome, thereby opened a completely new way of adaptation to the climatic and geographical conditions, different from the East Africa (for more details see Ibraimov, 1993Ibraimov, , 2010Ibraimov, , 2015Ibraimov, , 2017.…”