Search

The lipid composition of multi-lamellar vesicles of 1,2-dipalmitoyl- sn-glycero-3-phosphorylcholine exposed toCs γ-rays depends on the absorbed dose. In fact,P andH NMR analysis shows that four new molecular species are formed during the irradiation: a) 1-palmitoyl- sn-glycero-3-phosphorylcholine, b) 2-palmitoyl- sn-glycero-3-phosphorylcholine, c) glycerophosphorylcholine and d) free palmitic acid. Neglecting the species c), that is present only at high dose and in very small amount, the behaviour of molar fraction vs. dose is sublinear for a) and b), while for d) it is almost linear over all the dose range examined. The molecular and structural damage consequences onto the multi-lamellar vesicles, evidentiated by spin-labelling and DSC techniques, are discussed. It is clearly shown in particular, that the behaviour of the main transition does not depend on the concentration of the lysolecithins, but rather on that of the free palmitic acid, the role of which had previously been entirely neglected. [ABSTRACT FROM AUTHOR]

Nonbilayer structures, as lysophospholipid micelles, can be produced in membranes by gamma irradiation. Interesting information on the gamma-ray effect on the lysophospholipid organization can be obtained by spin-label techniques. Variations of the TEMPO partition are appreciable, particularly in the range of the lipid thermotropic transition, even from relatively low doses. With increasing dose this transition becomes more and more complex and wider, according to the previous thermodinamic analysis. [ABSTRACT FROM AUTHOR]

Copyright of Il Nuovo Cimento della Societa Italiana di Fisica: D is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)