Premium
Intramembrane particle movement revealed by study of an intercellular junction
Author(s) -
Green Colin R.
Publication year - 1982
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1982.tb00338.x
Subject(s) - ultrastructure , anatomy , biophysics , cell junction , septate junctions , tight junction , gap junction , fracture (geology) , particle (ecology) , biology , materials science , intracellular , chemistry , microbiology and biotechnology , cell , composite material , biochemistry , ecology
SUMMARY Comparison of results from thin section and freeze‐fracture techniques on the echinoderm epidermal septate junction has shown that a large degree of intramembrane particle translocation is possible during fixation and cryoprotection. The intramembrane and intermembrane components of the junction are apparently separated from each other in the process. Lanthanum tracer studies show that septa of this junction are double, straight, unbranched structures running around the cell apex. Freeze‐fracture of fixed tissue reveals junctional particles or pits in a broad band, also around the apical circumference of cells. However, they do not line up as would be expected after viewing septa in tangential sections and form a belt of randomly dispersed structures. In contrast, replicas of unfixed tissue show particles that clearly align in rows, often double, as are the septa in tangential views. It appears that intramembrane structural changes revealed by freeze‐fracture do not necessarily reflect corresponding intercellular changes.