three different types of outer membrane preparations were tested : ( i ) cellular outer membranes isolated from lysozyme spheroplasts , ( ii ) medium vesicles or outer membrane fragments released into the medium during growth , and ( iii ) periplasmic vesicles , or outer membrane fragments which were released from the cells during spheroplast formation and were therefore isolated in the periplasmic fraction .
C0007603
cellular
C0007634
cells