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Coupled phases and combinatorial selection in fluctuating hydrothermal pools: a scenario to guide experimental approaches to the origin of cellular life.

Damer B, Deamer D - Life (Basel) (2015)

Bottom Line: Two kinds of selective processes can then occur.The second is a chemical process in which rare combinations of encapsulated polymers form systems capable of capturing energy and nutrients to undergo growth by catalyzed polymerization.Given continued cycling over extended time spans, such combinatorial processes will give rise to molecular systems having the fundamental properties of life.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomolecular Engineering. bdamer@ucsc.edu.

ABSTRACT
Hydrothermal fields on the prebiotic Earth are candidate environments for biogenesis. We propose a model in which molecular systems driven by cycles of hydration and dehydration in such sites undergo chemical evolution in dehydrated films on mineral surfaces followed by encapsulation and combinatorial selection in a hydrated bulk phase. The dehydrated phase can consist of concentrated eutectic mixtures or multilamellar liquid crystalline matrices. Both conditions organize and concentrate potential monomers and thereby promote polymerization reactions that are driven by reduced water activity in the dehydrated phase. In the case of multilamellar lipid matrices, polymers that have been synthesized are captured in lipid vesicles upon rehydration to produce a variety of molecular systems. Each vesicle represents a protocell, an "experiment" in a natural version of combinatorial chemistry. Two kinds of selective processes can then occur. The first is a physical process in which relatively stable molecular systems will be preferentially selected. The second is a chemical process in which rare combinations of encapsulated polymers form systems capable of capturing energy and nutrients to undergo growth by catalyzed polymerization. Given continued cycling over extended time spans, such combinatorial processes will give rise to molecular systems having the fundamental properties of life.

No MeSH data available.


Related in: MedlinePlus

Aqueous phase in a hydrothermal pool. The hydrothermal aqueous phase is a mixture of potential monomers shown in red, and amphiphilic compounds that have assembled into micelles and vesicles (A). Upon drying (B), the amphiphilic compounds form multilamellar structures with solute molecules organized and concentrated between lamellae [17]. INSET: Freeze fracture image showing a multilamellar matrix of dried phospholipid [18].
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life-05-00872-f004: Aqueous phase in a hydrothermal pool. The hydrothermal aqueous phase is a mixture of potential monomers shown in red, and amphiphilic compounds that have assembled into micelles and vesicles (A). Upon drying (B), the amphiphilic compounds form multilamellar structures with solute molecules organized and concentrated between lamellae [17]. INSET: Freeze fracture image showing a multilamellar matrix of dried phospholipid [18].

Mentions: To illustrate how HD cycles can promote assembly of vesicles with encapsulated polymers, we will use the example of an aqueous phase consisting of a dilute solution of amphiphilic lipid-like compounds and potential monomers (Figure 4A). The pH is moderately acidic due to dissolved sulfur compounds and carbon dioxide. Rough mineral surfaces create localized sites for solutes and amphiphiles to accumulate during dehydration.


Coupled phases and combinatorial selection in fluctuating hydrothermal pools: a scenario to guide experimental approaches to the origin of cellular life.

Damer B, Deamer D - Life (Basel) (2015)

Aqueous phase in a hydrothermal pool. The hydrothermal aqueous phase is a mixture of potential monomers shown in red, and amphiphilic compounds that have assembled into micelles and vesicles (A). Upon drying (B), the amphiphilic compounds form multilamellar structures with solute molecules organized and concentrated between lamellae [17]. INSET: Freeze fracture image showing a multilamellar matrix of dried phospholipid [18].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390883&req=5

life-05-00872-f004: Aqueous phase in a hydrothermal pool. The hydrothermal aqueous phase is a mixture of potential monomers shown in red, and amphiphilic compounds that have assembled into micelles and vesicles (A). Upon drying (B), the amphiphilic compounds form multilamellar structures with solute molecules organized and concentrated between lamellae [17]. INSET: Freeze fracture image showing a multilamellar matrix of dried phospholipid [18].
Mentions: To illustrate how HD cycles can promote assembly of vesicles with encapsulated polymers, we will use the example of an aqueous phase consisting of a dilute solution of amphiphilic lipid-like compounds and potential monomers (Figure 4A). The pH is moderately acidic due to dissolved sulfur compounds and carbon dioxide. Rough mineral surfaces create localized sites for solutes and amphiphiles to accumulate during dehydration.

Bottom Line: Two kinds of selective processes can then occur.The second is a chemical process in which rare combinations of encapsulated polymers form systems capable of capturing energy and nutrients to undergo growth by catalyzed polymerization.Given continued cycling over extended time spans, such combinatorial processes will give rise to molecular systems having the fundamental properties of life.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomolecular Engineering. bdamer@ucsc.edu.

ABSTRACT
Hydrothermal fields on the prebiotic Earth are candidate environments for biogenesis. We propose a model in which molecular systems driven by cycles of hydration and dehydration in such sites undergo chemical evolution in dehydrated films on mineral surfaces followed by encapsulation and combinatorial selection in a hydrated bulk phase. The dehydrated phase can consist of concentrated eutectic mixtures or multilamellar liquid crystalline matrices. Both conditions organize and concentrate potential monomers and thereby promote polymerization reactions that are driven by reduced water activity in the dehydrated phase. In the case of multilamellar lipid matrices, polymers that have been synthesized are captured in lipid vesicles upon rehydration to produce a variety of molecular systems. Each vesicle represents a protocell, an "experiment" in a natural version of combinatorial chemistry. Two kinds of selective processes can then occur. The first is a physical process in which relatively stable molecular systems will be preferentially selected. The second is a chemical process in which rare combinations of encapsulated polymers form systems capable of capturing energy and nutrients to undergo growth by catalyzed polymerization. Given continued cycling over extended time spans, such combinatorial processes will give rise to molecular systems having the fundamental properties of life.

No MeSH data available.


Related in: MedlinePlus