Lamellar Systems in Myelin and Photoreceptors 



as Revealed by High-Resolution 



Electron Microscopy' 



H. Fernandez-Moran - 



Introduction 



Ultrastructure studies (Engstrom and Finean, 1958; Fernandez- 

 Moran, 1959b; Fernandez-Moran and Brown, 1958; Schmidt, 1937; 

 Schmitt, 1944; Schmitt et ah, 1935) of the regularly arranged sub- 

 microscopic layers which build up the nerve myelin sheath, photo- 

 receptors, chloroplasts, and numerous other types of "lamellar sys- 

 tems," have furnished the basis for a broad approach to related 

 problems of fundamental interest in the field of molecular biology. 

 Current biophysical and biochemical investigations are therefore 

 concerned not only with the nature of these multilayered structures 

 considered as specialized derivatives of the cell membrane, but also 

 with the distinctive repetitive features of their periodic arrav which 

 seem to underlie the specific processes of energy reception and trans- 

 fer in living organisms. 



Many lamellar structures may be regarded as model systems 

 which are particularly favorable for detailed investigation of cell- 



' This work was supported by Atomic Energy Commission Contract AT(30-1)- 

 2278 and by a grant (C-3174) from the National Institutes of Health. The author 

 is particularly indebted to Dr. William H. Sweet, Associate Professor of Neurosurgery, 

 Harvard Medical School, and to Dr. Raymond D. Adams, Bullard Professor of Neuro- 

 pathology, Harvard Medical School, for their generous assistance and support of this 

 project. It is also a pleasure to thank Professor Samuel C. Collins, Director of the 

 Cryogenic Engineering Laboratory, M. I. T., for his guidance and kind help in extend- 

 ing to us the facilities of his laboratory during the course of the liquid helium experi- 

 ments; and his assistant, Robert Cavileer, for his technical contribution in the design 

 and instrumentation of the liquid helium experiments. Sincere thanks are also due to 

 Frederick B. Merk, Ernest Shmid, and Joanne T. Frederick for their able technical 

 assistance; and to Gertrude Dole and Irene Brierley for their valuable help in pre- 

 paring ithe manuscript. 



^ Mixter Laboratories for Electron Microscopy Neurosurgical Service, Massachu- 

 setts Ceneral Hospital; and Department of Neurology and Psychology, Harvard Med- 

 ical School, Boston, Massachusetts. 



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