(A) Liposomes are prepared from rat brain microsomallipid and loaded with either Tb3+ or dipicolinic acid (OPA) to test fusion with the Tb/DPA method. (B) The addition of either Ca2+ or Mg2+ to loaded liposomes produces fluorescence, which is due to the formation of Tb-DPA complex. Since Ca2+quenches the fluorescence completely, only the fluorescent complex internal to vesicles is measured in the presence of this ion. (C) The fluorescence elicited by Mg2+ is much higher than that elicited by Ca2+ and is quenched by the addition of EOTA or Ca2+. (O) Rat brain microsomes can be disrupted by adding octylglucoside and reconstituted by removing it by dialysis. We use this procedure to load microsomes with DPA and Tb3+. This allows the use of the Tb/DPA method to test the fusion of rat brain microsomes. (E) Reconstituted microsomes fuse with liposomes and this fusion is similar to liposome- liposome fusion. On the other hand, reconstituted microsomes do not fuse among themselves.
Rat brain microsomes: aggregation and fusion of reconstituted vesicles
CORAZZI, Lanfranco;ARIENTI, Giuseppe
1989
Abstract
(A) Liposomes are prepared from rat brain microsomallipid and loaded with either Tb3+ or dipicolinic acid (OPA) to test fusion with the Tb/DPA method. (B) The addition of either Ca2+ or Mg2+ to loaded liposomes produces fluorescence, which is due to the formation of Tb-DPA complex. Since Ca2+quenches the fluorescence completely, only the fluorescent complex internal to vesicles is measured in the presence of this ion. (C) The fluorescence elicited by Mg2+ is much higher than that elicited by Ca2+ and is quenched by the addition of EOTA or Ca2+. (O) Rat brain microsomes can be disrupted by adding octylglucoside and reconstituted by removing it by dialysis. We use this procedure to load microsomes with DPA and Tb3+. This allows the use of the Tb/DPA method to test the fusion of rat brain microsomes. (E) Reconstituted microsomes fuse with liposomes and this fusion is similar to liposome- liposome fusion. On the other hand, reconstituted microsomes do not fuse among themselves.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.