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From vesicles to protocells: the roles of amphiphilic molecules.

Sakuma Y, Imai M - Life (Basel) (2015)

Bottom Line: It is very challenging to construct protocells from molecular assemblies.Here, we show that simple binary phospholipid vesicles have the potential to reproduce the relevant functions of adhesion, pore formation and self-reproduction of vesicles, by coupling the lipid geometries (spontaneous curvatures) and the phase separation.This achievement will elucidate the pathway from molecular assembly to cellular life.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Tohoku University, Aoba, Sendai 980-8578, Japan. sakuma@bio.phys.tohoku.ac.jp.

ABSTRACT
It is very challenging to construct protocells from molecular assemblies. An important step in this challenge is the achievement of vesicle dynamics that are relevant to cellular functions, such as membrane trafficking and self-reproduction, using amphiphilic molecules. Soft matter physics will play an important role in the development of vesicles that have these functions. Here, we show that simple binary phospholipid vesicles have the potential to reproduce the relevant functions of adhesion, pore formation and self-reproduction of vesicles, by coupling the lipid geometries (spontaneous curvatures) and the phase separation. This achievement will elucidate the pathway from molecular assembly to cellular life.

No MeSH data available.


Related in: MedlinePlus

Two tangent vesicles observed by phase contrast microscopy (a) and epi-fluorescence (b); one of the vesicles is functionalized by adenosine lipids and labeled by 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) (RhPE), and the other one is functionalized by thymidine lipids. Just after aggregation of the two vesicles, as attested by membrane deformation in the contact area (d), a fluorescent signal appeared on the non-labeled vesicle (c), denoting a lipid mixing. Fluorescent lipids carry on their redistribution after 3 min (e), until they reach equilibrium after 6 min (f). The bar is 20 μm (taken from [56]).
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life-05-00651-f010: Two tangent vesicles observed by phase contrast microscopy (a) and epi-fluorescence (b); one of the vesicles is functionalized by adenosine lipids and labeled by 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) (RhPE), and the other one is functionalized by thymidine lipids. Just after aggregation of the two vesicles, as attested by membrane deformation in the contact area (d), a fluorescent signal appeared on the non-labeled vesicle (c), denoting a lipid mixing. Fluorescent lipids carry on their redistribution after 3 min (e), until they reach equilibrium after 6 min (f). The bar is 20 μm (taken from [56]).

Mentions: The formation of the hemifusion intermediate during the fusion process is confirmed by a fluorescent lipid transfer experiment where fluorescent labeled lipids transfer from a labeled vesicle to a non-labeled vesicle through the hemifused membrane [56]. In this experiment, an attractive interaction between vesicles was introduced by adding functionalized lipids bearing the DNA bases, thymidine or adenosine, as headgroups (H-bond between nucleosides). This attractive interaction keeps the two giant vesicles at an intermembrane distance of 1 nm (nipples). For the lipid transfer experiment, two types of vesicles predominantly composed of DOPC were prepared. The first type contained adenosine lipids and fluorescent labeled lipids, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) (RhPE). The second type bore thymidine lipids and had no fluorescent lipids. When the two vesicles were brought into close proximity, the vesicles adhered spontaneously (Figure 10a,b). Immediately after the adhesion, a fluorescence signal was observed on the non-labeled vesicle (Figure 10c). During a few minutes, the fluorescence intensity on the thymidine-bearing vesicle increased, while the fluorescence intensity decreased on the adenosine-bearing vesicle (Figure 10e,f), indicating the formation of the hemifusion state. In this experiment, several adhering vesicles proceeded to fusion (~5%), and the remaining adhering vesicles reached equilibrium.


From vesicles to protocells: the roles of amphiphilic molecules.

Sakuma Y, Imai M - Life (Basel) (2015)

Two tangent vesicles observed by phase contrast microscopy (a) and epi-fluorescence (b); one of the vesicles is functionalized by adenosine lipids and labeled by 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) (RhPE), and the other one is functionalized by thymidine lipids. Just after aggregation of the two vesicles, as attested by membrane deformation in the contact area (d), a fluorescent signal appeared on the non-labeled vesicle (c), denoting a lipid mixing. Fluorescent lipids carry on their redistribution after 3 min (e), until they reach equilibrium after 6 min (f). The bar is 20 μm (taken from [56]).
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Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390873&req=5

life-05-00651-f010: Two tangent vesicles observed by phase contrast microscopy (a) and epi-fluorescence (b); one of the vesicles is functionalized by adenosine lipids and labeled by 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) (RhPE), and the other one is functionalized by thymidine lipids. Just after aggregation of the two vesicles, as attested by membrane deformation in the contact area (d), a fluorescent signal appeared on the non-labeled vesicle (c), denoting a lipid mixing. Fluorescent lipids carry on their redistribution after 3 min (e), until they reach equilibrium after 6 min (f). The bar is 20 μm (taken from [56]).
Mentions: The formation of the hemifusion intermediate during the fusion process is confirmed by a fluorescent lipid transfer experiment where fluorescent labeled lipids transfer from a labeled vesicle to a non-labeled vesicle through the hemifused membrane [56]. In this experiment, an attractive interaction between vesicles was introduced by adding functionalized lipids bearing the DNA bases, thymidine or adenosine, as headgroups (H-bond between nucleosides). This attractive interaction keeps the two giant vesicles at an intermembrane distance of 1 nm (nipples). For the lipid transfer experiment, two types of vesicles predominantly composed of DOPC were prepared. The first type contained adenosine lipids and fluorescent labeled lipids, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) (RhPE). The second type bore thymidine lipids and had no fluorescent lipids. When the two vesicles were brought into close proximity, the vesicles adhered spontaneously (Figure 10a,b). Immediately after the adhesion, a fluorescence signal was observed on the non-labeled vesicle (Figure 10c). During a few minutes, the fluorescence intensity on the thymidine-bearing vesicle increased, while the fluorescence intensity decreased on the adenosine-bearing vesicle (Figure 10e,f), indicating the formation of the hemifusion state. In this experiment, several adhering vesicles proceeded to fusion (~5%), and the remaining adhering vesicles reached equilibrium.

Bottom Line: It is very challenging to construct protocells from molecular assemblies.Here, we show that simple binary phospholipid vesicles have the potential to reproduce the relevant functions of adhesion, pore formation and self-reproduction of vesicles, by coupling the lipid geometries (spontaneous curvatures) and the phase separation.This achievement will elucidate the pathway from molecular assembly to cellular life.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Tohoku University, Aoba, Sendai 980-8578, Japan. sakuma@bio.phys.tohoku.ac.jp.

ABSTRACT
It is very challenging to construct protocells from molecular assemblies. An important step in this challenge is the achievement of vesicle dynamics that are relevant to cellular functions, such as membrane trafficking and self-reproduction, using amphiphilic molecules. Soft matter physics will play an important role in the development of vesicles that have these functions. Here, we show that simple binary phospholipid vesicles have the potential to reproduce the relevant functions of adhesion, pore formation and self-reproduction of vesicles, by coupling the lipid geometries (spontaneous curvatures) and the phase separation. This achievement will elucidate the pathway from molecular assembly to cellular life.

No MeSH data available.


Related in: MedlinePlus