Aqueous dispersions of DMPG in low salt contain leaky vesicles
Autor(a) principal: | |
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Data de Publicação: | 2012 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNIFESP |
Texto Completo: | http://dx.doi.org/10.1016/j.chemphyslip.2011.12.007 http://repositorio.unifesp.br/handle/11600/34541 |
Resumo: | Aqueous dispersions of dimyristoyl phosphatidylglycerol (DMPG), at low ionic strength, display uncommon thermal behavior. Models for such behavior need to assign a form to the lipid aggregate. Although most studies accept the presence of lipid vesicles in the lipid gel and fluid phases, this is still controversial. With electron spin resonance (ESR) spectra of spin labels incorporated into DMPG aggregates, quantification of [C-14]sucrose entrapped by the aggregates, and viscosity measurements, we demonstrate the existence of leaky vesicles in dispersions of DMPG at low ionic strength, in both gel and fluid phases of the lipid. As a control system, the ubiquitous lipid dimyristoyl phosphatidylcholine (DMPC) was used. for DMPG in the gel phase, spin labeling only indicated the presence of lipid bilayers, strongly suggesting that DMPG molecules are organized as vesicles and not micelles or bilayer fragments (bicelles), as the latter has a non-bilayer structure at the edges. Quantification of [C-14]sucrose entrapping by DMPG aggregates revealed the presence of highly leaky vesicles. Due to the short hydrocarbon chains (C-14 atoms), DMPC vesicles were also found to be partially permeable to sucrose, but not as much as DMPG vesicles. Viscosity measurements, with the calculation of the intrinsic viscosiiy of the lipid aggregate, showed that DMPG vesicles are rather similar in the gel and fluid phases, and quite different from aggregates observed along the gel-fluid transition. Taken together, our data strongly supports that DMPG forms leaky vesicles at both gel and fluid phases. (C) 2011 Elsevier Ireland Ltd. All rights reserved. |
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Aqueous dispersions of DMPG in low salt contain leaky vesiclesDMPGLeaky vesiclesSpin labels[C-14]sucrose entrapmentIntrinsic viscosityAqueous dispersions of dimyristoyl phosphatidylglycerol (DMPG), at low ionic strength, display uncommon thermal behavior. Models for such behavior need to assign a form to the lipid aggregate. Although most studies accept the presence of lipid vesicles in the lipid gel and fluid phases, this is still controversial. With electron spin resonance (ESR) spectra of spin labels incorporated into DMPG aggregates, quantification of [C-14]sucrose entrapped by the aggregates, and viscosity measurements, we demonstrate the existence of leaky vesicles in dispersions of DMPG at low ionic strength, in both gel and fluid phases of the lipid. As a control system, the ubiquitous lipid dimyristoyl phosphatidylcholine (DMPC) was used. for DMPG in the gel phase, spin labeling only indicated the presence of lipid bilayers, strongly suggesting that DMPG molecules are organized as vesicles and not micelles or bilayer fragments (bicelles), as the latter has a non-bilayer structure at the edges. Quantification of [C-14]sucrose entrapping by DMPG aggregates revealed the presence of highly leaky vesicles. Due to the short hydrocarbon chains (C-14 atoms), DMPC vesicles were also found to be partially permeable to sucrose, but not as much as DMPG vesicles. Viscosity measurements, with the calculation of the intrinsic viscosiiy of the lipid aggregate, showed that DMPG vesicles are rather similar in the gel and fluid phases, and quite different from aggregates observed along the gel-fluid transition. Taken together, our data strongly supports that DMPG forms leaky vesicles at both gel and fluid phases. (C) 2011 Elsevier Ireland Ltd. All rights reserved.Univ São Paulo, Inst Fis, BR-01498 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biofis, São Paulo, BrazilUniv São Paulo, Inst Quim, BR-01498 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biofis, São Paulo, BrazilWeb of ScienceUSPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Elsevier B.V.Universidade de São Paulo (USP)Universidade Federal de São Paulo (UNIFESP)Barroso, Rafael P.Perez, Katia Regina [UNIFESP]Cuccovia, Iolanda M.Lamy, M. Teresa2016-01-24T14:17:49Z2016-01-24T14:17:49Z2012-02-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersion169-177application/pdfhttp://dx.doi.org/10.1016/j.chemphyslip.2011.12.007Chemistry and Physics of Lipids. Clare: Elsevier B.V., v. 165, n. 2, p. 169-177, 2012.10.1016/j.chemphyslip.2011.12.007WOS000301631700005.pdf0009-3084http://repositorio.unifesp.br/handle/11600/34541WOS:000301631700005engChemistry and Physics of Lipidsinfo:eu-repo/semantics/openAccesshttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policyreponame:Repositório Institucional da UNIFESPinstname:Universidade Federal de São Paulo (UNIFESP)instacron:UNIFESP2024-07-31T23:51:32Zoai:repositorio.unifesp.br/:11600/34541Repositório InstitucionalPUBhttp://www.repositorio.unifesp.br/oai/requestbiblioteca.csp@unifesp.bropendoar:34652024-07-31T23:51:32Repositório Institucional da UNIFESP - Universidade Federal de São Paulo (UNIFESP)false |
dc.title.none.fl_str_mv |
Aqueous dispersions of DMPG in low salt contain leaky vesicles |
title |
Aqueous dispersions of DMPG in low salt contain leaky vesicles |
spellingShingle |
Aqueous dispersions of DMPG in low salt contain leaky vesicles Barroso, Rafael P. DMPG Leaky vesicles Spin labels [C-14]sucrose entrapment Intrinsic viscosity |
title_short |
Aqueous dispersions of DMPG in low salt contain leaky vesicles |
title_full |
Aqueous dispersions of DMPG in low salt contain leaky vesicles |
title_fullStr |
Aqueous dispersions of DMPG in low salt contain leaky vesicles |
title_full_unstemmed |
Aqueous dispersions of DMPG in low salt contain leaky vesicles |
title_sort |
Aqueous dispersions of DMPG in low salt contain leaky vesicles |
author |
Barroso, Rafael P. |
author_facet |
Barroso, Rafael P. Perez, Katia Regina [UNIFESP] Cuccovia, Iolanda M. Lamy, M. Teresa |
author_role |
author |
author2 |
Perez, Katia Regina [UNIFESP] Cuccovia, Iolanda M. Lamy, M. Teresa |
author2_role |
author author author |
dc.contributor.none.fl_str_mv |
Universidade de São Paulo (USP) Universidade Federal de São Paulo (UNIFESP) |
dc.contributor.author.fl_str_mv |
Barroso, Rafael P. Perez, Katia Regina [UNIFESP] Cuccovia, Iolanda M. Lamy, M. Teresa |
dc.subject.por.fl_str_mv |
DMPG Leaky vesicles Spin labels [C-14]sucrose entrapment Intrinsic viscosity |
topic |
DMPG Leaky vesicles Spin labels [C-14]sucrose entrapment Intrinsic viscosity |
description |
Aqueous dispersions of dimyristoyl phosphatidylglycerol (DMPG), at low ionic strength, display uncommon thermal behavior. Models for such behavior need to assign a form to the lipid aggregate. Although most studies accept the presence of lipid vesicles in the lipid gel and fluid phases, this is still controversial. With electron spin resonance (ESR) spectra of spin labels incorporated into DMPG aggregates, quantification of [C-14]sucrose entrapped by the aggregates, and viscosity measurements, we demonstrate the existence of leaky vesicles in dispersions of DMPG at low ionic strength, in both gel and fluid phases of the lipid. As a control system, the ubiquitous lipid dimyristoyl phosphatidylcholine (DMPC) was used. for DMPG in the gel phase, spin labeling only indicated the presence of lipid bilayers, strongly suggesting that DMPG molecules are organized as vesicles and not micelles or bilayer fragments (bicelles), as the latter has a non-bilayer structure at the edges. Quantification of [C-14]sucrose entrapping by DMPG aggregates revealed the presence of highly leaky vesicles. Due to the short hydrocarbon chains (C-14 atoms), DMPC vesicles were also found to be partially permeable to sucrose, but not as much as DMPG vesicles. Viscosity measurements, with the calculation of the intrinsic viscosiiy of the lipid aggregate, showed that DMPG vesicles are rather similar in the gel and fluid phases, and quite different from aggregates observed along the gel-fluid transition. Taken together, our data strongly supports that DMPG forms leaky vesicles at both gel and fluid phases. (C) 2011 Elsevier Ireland Ltd. All rights reserved. |
publishDate |
2012 |
dc.date.none.fl_str_mv |
2012-02-01 2016-01-24T14:17:49Z 2016-01-24T14:17:49Z |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1016/j.chemphyslip.2011.12.007 Chemistry and Physics of Lipids. Clare: Elsevier B.V., v. 165, n. 2, p. 169-177, 2012. 10.1016/j.chemphyslip.2011.12.007 WOS000301631700005.pdf 0009-3084 http://repositorio.unifesp.br/handle/11600/34541 WOS:000301631700005 |
url |
http://dx.doi.org/10.1016/j.chemphyslip.2011.12.007 http://repositorio.unifesp.br/handle/11600/34541 |
identifier_str_mv |
Chemistry and Physics of Lipids. Clare: Elsevier B.V., v. 165, n. 2, p. 169-177, 2012. 10.1016/j.chemphyslip.2011.12.007 WOS000301631700005.pdf 0009-3084 WOS:000301631700005 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Chemistry and Physics of Lipids |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess http://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy |
eu_rights_str_mv |
openAccess |
rights_invalid_str_mv |
http://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy |
dc.format.none.fl_str_mv |
169-177 application/pdf |
dc.publisher.none.fl_str_mv |
Elsevier B.V. |
publisher.none.fl_str_mv |
Elsevier B.V. |
dc.source.none.fl_str_mv |
reponame:Repositório Institucional da UNIFESP instname:Universidade Federal de São Paulo (UNIFESP) instacron:UNIFESP |
instname_str |
Universidade Federal de São Paulo (UNIFESP) |
instacron_str |
UNIFESP |
institution |
UNIFESP |
reponame_str |
Repositório Institucional da UNIFESP |
collection |
Repositório Institucional da UNIFESP |
repository.name.fl_str_mv |
Repositório Institucional da UNIFESP - Universidade Federal de São Paulo (UNIFESP) |
repository.mail.fl_str_mv |
biblioteca.csp@unifesp.br |
_version_ |
1814268370101469184 |