| Popis: |
Dry-cleaving is introduced as a new technique for visualization of the cytoplasmic side of adherent membrane in cultured cells. Basically, cells are fixed and critical point-dried in situ and subsequently broken by means of adhesive tape. The plane of cleavage is dependent on the fixation scheme applied. The method has been used for the study of substrate-adherent membranes in primary cultured hepatocytes, in combination with a variety of scanning- and transmission electron microscopic (SEM and TEM) techniques. It is shown that a two-dimensional filamentous web is apposed to the entire hepatocytic plasma membrane. Particular patterns within the web can be recognized, among which a ‘spider-web’ pattern appears to be associated with the early stage of coated vesicle development. During successive stages of coated vesicle formation the coat appears to be connected to filaments, directly in its mid-stage and by means of radial spokes in its final stage. The significance of the spider-web pattern with respect to the endocytotic process and the interrelationship of coated vesicles and filamentous structures are discussed. |
