Self-reproduction of micelles and vesicles

In general, the mechanism of self-reproduction of micelles and vesicles can be considered an autopoietic mechanism, since growth and eventually division comes from within the structure itself. This point will be considered again in Chapter 8, on autopoiesis, where the mechanism of the self-reproduction process will also be discussed. 

In the various reviews on self-reproduction in recent years, practically no mention is made of such micelles or vesicle systems. The reason lies most prohahly in the bias of classic hiochemical literature, according to which self-replication is tantamount to nucleic acid systems lacking this are therefore deemed not to he relevant. In this particular regard, it is argued that self-reproduction of micelles and vesicles proceeds without transmission of information. 

The term chemical autopoiesis indicates the experimental implementation of autopoiesis in the chemistry laboratory. The most well known of these processes is the self-reproduction of micelles and vesicles. This has been discussed in the previous chapter, where the original idea of Francisco Varela and myself was to work with bounded systems that would produce their own components due to an internal reaction, respecting the scheme illustrated in Figure 8.3. We came up with the idea of using reverse micelles (refer back to Figure 7.13) with two reagents. 

Self-reproduction of micelles and vesicles models for the mechanisms of life from the perspective of compartmented chemistry. Adv. Chem. Phys., 92,425-38. 

The main point of this chapter is to show that supramolecular aggregates can play an important role in the early history of the origin of life. The main driving force in all processes we have illustrated is the hydrophobic interaction—this is responsible for the self-assembly of vesicles, for the binding of hydrophobic substances to the vesicle membranes and the corresponding autocatalytic self-reproduction of micelles and vesicles, as well as for the corresponding chemical events of polymerization. Since the hydrophobic forces take place generally spontaneously and with... 

So far, only the self-replication mechanisms of linear molecules have been described it is now time to consider closed spherical structures, such as micelles and vesicles. Here, the term self-reproduction will be used rather than self-replication, because, as it will be seen, the population increase is generally based on statistical processes. The subject of micelles and vesicles self-reproduction is dealt with in other chapters in this book a certain degree of repetition and/or mis-match is unavoidable. 

We have also learned that self-replication is not a prerogative only of nucleic acids, but it can be shared by different kinds of chemical families see the formose reaction, the self-replicating peptides, and the self-reproducing micelles and vesicles. The list should include the cellular automata and the corresponding devices of artificial life. Self-reproduction of vesicles and liposomes is important because it represents a model for cell reproduction. 

Reverse micelles are the first compartment structures for which the phenomenon of micelle self-reproduction has been described (Bachman et al., 1990 1991). This experimental work was a follow up of a theoretical study by Varela and Luisi (Luisi and Varela, 1990), and is it this that eventually brought to light the self-reproduction of aqueous micelles and vesicles. This has been covered already in Chapter 7, on the chemistry of self-reproduction. 

We have mentioned before the possibility of combining chemical evolution with self-replication. In principle, chemical evolution can be associated to self-reproducing micelles or vesicles. There are in principle two ways to conceive this in this case on the one hand, the surfactants of the self-reproducing vesicles could be chemically transformed during their reproduction cycles into compounds which may give rise to more efficient cell-like compartments. This possibility has been discussed theoretically some time ago. On the other hand, the supramolecular structure can help and determine the evolution of internalized compounds—i.e. permitting certain reactions and avoiding others thanks to the semipermeable character of the membrane. As already mentioned, studies of this type with vesicles still remain to be initiated. 

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