RESUMEN
The results of a laser picosecond microspectrofluorometric study of the spectral and kinetic characteristics of haematoporphyrin (Hp) fluorescence at various sites in cultured SPEV cells and phosphatidylcholine liposomes are presented. The computer-controlled detection system is based on the single-photon counting method with picosecond time resolution. In aqueous medium, the Hp fluorescence spectrum is characterized by two bands at 615 and 675 nm. In living cells and liposomes, Hp fluorescence is red shifted to 630 and 690 nm. In addition a new band at 665 nm is detected. The dependence of this band on the incubation time and Hp concentration was investigated. The fluorescence decay kinetics of Hp in a culture medium, liposome and a cell nuclear membrane were measured. Possible Hp aggregate formation in the lipid bilayer and its implications are discussed.
Asunto(s)
Hematoporfirinas/química , Liposomas , Animales , Línea Celular , Cinética , Rayos Láser , Espectrometría de Fluorescencia/instrumentación , Espectrometría de Fluorescencia/métodos , Porcinos , Factores de TiempoRESUMEN
The melanophores of the teleost Gymnocorymbus ternetzi are filled with pigment granules, melanosomes, which in response to appropriate treatments, can disperse throughout the cytoplasm or form an aggregate in the cell center. Melanophores with the dispersed pigment were irradiated by a laser microbeam, focused on the cell center by the microscope objective. If the average energy of the microbeam was 6-7 microJ, either the center of the melanophore was damaged and a single ring-shaped fragment was formed, or the cell was broken into several fragments of smaller size. The fragments retained their ability to move the pigment granules. In ring-shaped fragments, after adrenaline treatment, the melanosomes formed a ring-shaped aggregate moving away from both outer and inner (irradiation-produced) margins of the fragment. The smaller fragments treated with adrenaline moved the pigment to their centers. Both small and ring-shaped fragments could aggregate melanosomes as soon as 5 minutes after irradiation.