Aqueous dispersions of DMPG in low salt contain leaky vesicles

Detalhes bibliográficos
Autor(a) principal: Barroso, Rafael P.
Data de Publicação: 2012
Outros Autores: Perez, Katia Regina [UNIFESP], Cuccovia, Iolanda M., Lamy, M. Teresa
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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spelling 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
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