title: Radiation damage on Langmuir monolayers of the anionic 1.2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (sodium salt)(DPPG) phospholipid at the air-DNA solution interface.
abstract: The resilience of cells to ultraviolet (UV) irradiation is probably associated with the effects induced in biological molecules such as DNA and in the cell membrane. In this study, we investigated UV damage to the anionic 1.2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (sodium salt) (DPPG) phospholipid, which is an important component of cell membranes. In films cast from DPPG emulsions, UV irradiation induced cleavage of C-O, C=O and -PO(2-) bonds, while in Langmuir monolayers at the air/water interface representing the cell membrane this irradiation caused the monolayer stability to decrease. When DNA was present in the subphase, however, the effects from UV irradiation were smaller, since the ionic products from degradation of either DPPG or DNA stabilize the intact DPPG molecules. This mechanism may explain why UV irradiation does not cause immediate cell collapse, thus providing time for the cellular machinery to repair elements damaged by UV.
authors.affiliation: CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Paulo J
authors.initials: PJ
authors.lastname: Gomes
authors.affiliation: Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade de Lisboa, Av Rovisco Pais, 1049-001 Lisboa, Portugal.
authors.forename: Amélia M P S
authors.initials: AM
authors.lastname: Gonçalves da Silva
authors.affiliation: CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Paulo A
authors.initials: PA
authors.lastname: Ribeiro
authors.affiliation: Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, São Paulo, Brazil.
authors.forename: Osvaldo N
authors.initials: ON
authors.lastname: Oliveira
authors.affiliation: CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal. Electronic address: mfr@fct.unl.pt.
authors.forename: Maria
authors.initials: M
authors.lastname: Raposo
mesh_terms: D000388:Air; D000838:Anions; D004247:DNA / Q000737:chemistry*; D010715:Phosphatidylglycerols / Q000737:chemistry* / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D000838:Anions; D010715:Phosphatidylglycerols; D004247:DNA; C030345:1,2-dipalmitoylphosphatidylglycerol
keywords: DNA; DPPG; Langmuir films; Radiation damage; UV radiation