Limits...
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 adhering GUVs composed of DPPE/DOPC (= 6/4) in a fluorescent lipid transfer experiment, (a) phase contrast + fluorescence image and (b) fluorescence image for adhering GUVs just after they contact. The bright GUV is a fluorescently labeled GUV, and the non-labeled GUV is positioned at the left side of the labeled GUV (detected by the phase contrast image in (a) and not seen in (b)). After 10 min, a fluorescence signal appears in the non-labeled GUV in the neighborhood of the contacting area (indicated by an arrow) in the fluorescence image (c) (taken from [48]).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4390873&req=5

life-05-00651-f015: Two adhering GUVs composed of DPPE/DOPC (= 6/4) in a fluorescent lipid transfer experiment, (a) phase contrast + fluorescence image and (b) fluorescence image for adhering GUVs just after they contact. The bright GUV is a fluorescently labeled GUV, and the non-labeled GUV is positioned at the left side of the labeled GUV (detected by the phase contrast image in (a) and not seen in (b)). After 10 min, a fluorescence signal appears in the non-labeled GUV in the neighborhood of the contacting area (indicated by an arrow) in the fluorescence image (c) (taken from [48]).

Mentions: The adhesion through the stalk intermediate was confirmed by a fluorescence lipid transfer experiment, as shown in Figure 15. Here, two types of binary vesicles composed of DOPC and DPPE were prepared. The first type contained the fluorescently labeled lipids, TR-DHPE, and the second type had no fluorescence lipids. Two phase separating vesicles of different types were brought into contact for adhesion using micro-manipulation (Figure 15a, phase contrast and fluorescence overlapped image). Just after the adhesion, the labeled vesicle showed a fluorescence signal, whereas the non-labeled vesicle could not be detected by a fluorescence microscope observation, as shown in Figure 15b. Slightly after the adhesion (several minutes), a fluorescence signal was observed in the neighborhood of the contact area on the non-labeled vesicle, as shown by the arrow in Figure 15c, indicating the hemifusion through the inverse-cone lipid domains. It should be noted that the lipid transfer was observed in a limited region due to the irregular domain shape. The formation of the stalk leads to a decrease in the bending energy and line energy in the adhering monolayers, which stabilizes the hemifusion state. Unfortunately, it is difficult to induce a transformation of this hemifusion state to the fusion state due to the stability of the intermediate. Precise control of the lipid shape might be needed to achieve fusion.


From vesicles to protocells: the roles of amphiphilic molecules.

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

Two adhering GUVs composed of DPPE/DOPC (= 6/4) in a fluorescent lipid transfer experiment, (a) phase contrast + fluorescence image and (b) fluorescence image for adhering GUVs just after they contact. The bright GUV is a fluorescently labeled GUV, and the non-labeled GUV is positioned at the left side of the labeled GUV (detected by the phase contrast image in (a) and not seen in (b)). After 10 min, a fluorescence signal appears in the non-labeled GUV in the neighborhood of the contacting area (indicated by an arrow) in the fluorescence image (c) (taken from [48]).
© Copyright Policy
Related In: Results  -  Collection

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

life-05-00651-f015: Two adhering GUVs composed of DPPE/DOPC (= 6/4) in a fluorescent lipid transfer experiment, (a) phase contrast + fluorescence image and (b) fluorescence image for adhering GUVs just after they contact. The bright GUV is a fluorescently labeled GUV, and the non-labeled GUV is positioned at the left side of the labeled GUV (detected by the phase contrast image in (a) and not seen in (b)). After 10 min, a fluorescence signal appears in the non-labeled GUV in the neighborhood of the contacting area (indicated by an arrow) in the fluorescence image (c) (taken from [48]).
Mentions: The adhesion through the stalk intermediate was confirmed by a fluorescence lipid transfer experiment, as shown in Figure 15. Here, two types of binary vesicles composed of DOPC and DPPE were prepared. The first type contained the fluorescently labeled lipids, TR-DHPE, and the second type had no fluorescence lipids. Two phase separating vesicles of different types were brought into contact for adhesion using micro-manipulation (Figure 15a, phase contrast and fluorescence overlapped image). Just after the adhesion, the labeled vesicle showed a fluorescence signal, whereas the non-labeled vesicle could not be detected by a fluorescence microscope observation, as shown in Figure 15b. Slightly after the adhesion (several minutes), a fluorescence signal was observed in the neighborhood of the contact area on the non-labeled vesicle, as shown by the arrow in Figure 15c, indicating the hemifusion through the inverse-cone lipid domains. It should be noted that the lipid transfer was observed in a limited region due to the irregular domain shape. The formation of the stalk leads to a decrease in the bending energy and line energy in the adhering monolayers, which stabilizes the hemifusion state. Unfortunately, it is difficult to induce a transformation of this hemifusion state to the fusion state due to the stability of the intermediate. Precise control of the lipid shape might be needed to achieve fusion.

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