Complementary plasma membrane fracture faces in freeze-etch replicas

Recent studies have all shown that membranes fracture internally during freeze-etching or freeze-cleaving, confirming that 2 internal membrane faces are produced. That these faces are not complementary is one of the main features of freeze-etch replicas still requiring explanation. In the present investigation certain plasma membranes in light organs of the New Zealand glow worm are found to be an exception to this general rule of non-complementarity, as there is a sufficient number of holes present in one membrane face to match the number of particles on the other. This finding suggests that most of the theories put forward to explain non-complementarity do not apply and that holes are probably lost in most membrane faces by distortion during fracturing.