Distribution and biophysical properties of fluorescent lipids on the surface of adultSchistosoma mansoni

Abstract

SUMMARYThe properties of 4 fluorescent lipid compounds in the surface membrane of adult maleSchistosoma mansoniworms were examined by fluorescent microscopy and fluorescent recovery after photobleaching (FRAP). The data suggest that the probes N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl) sphingosine (BODIPY FL ceramide) and PKH2 pass through the outer membrane and enter structures in or below the membrane. In contrast 5-(N-octadecanoyl)aminofluorescein (AF18) and N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl) sphingosylphosphocholine (BODIPY FL sphingomyelin) insert into the outer monolayer. The DLvalues of these latter 2 compounds, 8·83 ± 2·35 × 10−9cm2s−1and 2·76 ± 0·53 × 10−9cm2s−1, respectively, suggest that they enter different domains. Furthermore, it was observed that both BODIPY FL ceramide and BODIPY FL sphingomyelin entered particular structures in or under the surface membrane. The possible nature of these particles is discussed.