TY - JOUR
T1 - Studies on precellular evolution
T2 - The encapsulation of polyribonucleotides by liposomes
AU - Baeza, I.
AU - Ibañez, M.
AU - Santiago, J. C.
AU - Wong, C.
AU - Lazcano, A.
AU - Oró, J.
N1 - Funding Information:
Several conversations with Drs. Lynn Margulis and David Deamer on the role of membranes and liposomes in prebiological and biological evolution are gratefully acknowledged by A.L. and 3.0. Research reported in this paper was supported by NASA Grant NGR 44-005-002 to 3.0. lIe are indebted to Dr. Carlos Arguello for his help in preparing the diagram of Fig.
PY - 1986
Y1 - 1986
N2 - Liposomes are 5 to 50 micron vesicles with an internal aqueous environment, whose amphiphilic lipidic components self-assemble into systems with at least one double-layered membrane. Liposomes have been suggested as possible models of precellular systems formed in the early Archean Earth from lipids of non-enzymatic origin. Since it is generally accepted that RNA molecules preceded double-stranded DNA molecules as genetic material, we have studied the encapsulation of polyribonucleotides within liposomes made from dipalmitoyl phosphatidylcholine, and from egg yolk phosphatidylcholine to which cholesterol was added in some cases. The liposomes were prepared under anoxic conditions following the reverse phase evaporation method described by Szoka and Papahadjopoulos /1/. Quantitative determinations show that approximately 50% of the available lipids form liposomes, and that up to 5% of the polyribonucleotides can be entrapped by them. We have also studied the encapsulation of polyribonucleotides in the presence of 1) urea and cyanamide, two non-electrolytes that have been used as prebiotic condensing agents, and 2) of Zn++ and Pb++, two cations employed in the non-enzymatic template-directed synthesis of polyribonucleotides from activated nucleotides.
AB - Liposomes are 5 to 50 micron vesicles with an internal aqueous environment, whose amphiphilic lipidic components self-assemble into systems with at least one double-layered membrane. Liposomes have been suggested as possible models of precellular systems formed in the early Archean Earth from lipids of non-enzymatic origin. Since it is generally accepted that RNA molecules preceded double-stranded DNA molecules as genetic material, we have studied the encapsulation of polyribonucleotides within liposomes made from dipalmitoyl phosphatidylcholine, and from egg yolk phosphatidylcholine to which cholesterol was added in some cases. The liposomes were prepared under anoxic conditions following the reverse phase evaporation method described by Szoka and Papahadjopoulos /1/. Quantitative determinations show that approximately 50% of the available lipids form liposomes, and that up to 5% of the polyribonucleotides can be entrapped by them. We have also studied the encapsulation of polyribonucleotides in the presence of 1) urea and cyanamide, two non-electrolytes that have been used as prebiotic condensing agents, and 2) of Zn++ and Pb++, two cations employed in the non-enzymatic template-directed synthesis of polyribonucleotides from activated nucleotides.
UR - http://www.scopus.com/inward/record.url?scp=0023039857&partnerID=8YFLogxK
U2 - 10.1016/0273-1177(86)90273-5
DO - 10.1016/0273-1177(86)90273-5
M3 - Artículo
SN - 0273-1177
VL - 6
SP - 39
EP - 43
JO - Advances in Space Research
JF - Advances in Space Research
IS - 11
ER -