Abstract
Somatic muscle cells of Ascaris lumbricoides consist of three differently specialized components referred to as the fiber, which contains the contractile apparatus (described previously), the belly, and the arm. The belly is shown to be a sac of glycogen, which is depleted during starvation of the animal. The arm extends to a nerve cord where it establishes a myoneural junction characterized by giant mitochondria and clusters of vesicles in the nerve fibers and by a 500 A neuromuscular gap. The arms, which have been shown to be "electrically interconnected" in the vicinity of the nerve cord, form "tight junctions" with one another in just this region. At high magnification, these junctions can be resolved into several types. In some there is fusion of the outer leaflets of the membranes with formation of an intermediate line. Others resemble septate desmosomes in that a residual extracellular space ∼20 A in width remains between the membranes, but the outer leaflets are interconnected across the gap. It is suggested that the term "tight junction" encompasses a variety of structures distinguishable only at high magnification and that the different variations are not necessarily equivalent functionally.
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Selected References
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- BENNETT M. V., ALJURE E., NAKAJIMA Y., PAPPAS G. D. Electrotonic junctions between teleost spinal neurons: electrophysiology and ultrastructure. Science. 1963 Jul 19;141(3577):262–264. doi: 10.1126/science.141.3577.262. [DOI] [PubMed] [Google Scholar]
- BIRKS R., HUXLEY H. E., KATZ B. The fine structure of the neuromuscular junction of the frog. J Physiol. 1960 Jan;150:134–144. doi: 10.1113/jphysiol.1960.sp006378. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DEBELL J. T., DELCASTILLO J., SANCHEZ V. ELECTROPHYSIOLOGY OF THE SOMATIC MUSCLE CELLS OF ASCARIS LUMBRICOIDES. J Cell Physiol. 1963 Oct;62:159–177. doi: 10.1159/000007808. [DOI] [PubMed] [Google Scholar]
- DELCASTILLO J., DEMELLO W. C., MORALES T. MECHANISM OF THE PARALYSING ACTION OF PIPERAZINE ON ASCARIS MUSCLE. Br J Pharmacol Chemother. 1964 Jun;22:463–477. doi: 10.1111/j.1476-5381.1964.tb01701.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dewey M. M., Barr L. Intercellular Connection between Smooth Muscle Cells: the Nexus. Science. 1962 Aug 31;137(3531):670–672. doi: 10.1126/science.137.3531.670-a. [DOI] [PubMed] [Google Scholar]
- ELFVIN L. G. The ultrastructure of the nodes of Ranvier in cat sympathetic nerve fibers. J Ultrastruct Res. 1961 Aug;5:374–387. doi: 10.1016/s0022-5320(61)80014-2. [DOI] [PubMed] [Google Scholar]
- FARQUHAR M. G., PALADE G. E. Junctional complexes in various epithelia. J Cell Biol. 1963 May;17:375–412. doi: 10.1083/jcb.17.2.375. [DOI] [PMC free article] [PubMed] [Google Scholar]
- FURSHPAN E. J., POTTER D. D. Transmission at the giant motor synapses of the crayfish. J Physiol. 1959 Mar 3;145(2):289–325. doi: 10.1113/jphysiol.1959.sp006143. [DOI] [PMC free article] [PubMed] [Google Scholar]
- REVEL J. P., NAPOLITANO L., FAWCETT D. W. Identification of glycogen in electron micrographs of thin tissue sections. J Biophys Biochem Cytol. 1960 Dec;8:575–589. doi: 10.1083/jcb.8.3.575. [DOI] [PMC free article] [PubMed] [Google Scholar]
- RICHARDSON K. C., JARETT L., FINKE E. H. Embedding in epoxy resins for ultrathin sectioning in electron microscopy. Stain Technol. 1960 Nov;35:313–323. doi: 10.3109/10520296009114754. [DOI] [PubMed] [Google Scholar]
- RICHARDSON K. C. THE FINE STRUCTURE OF THE ALBINO RABBIT IRIS WITH SPECIAL REFERENCE TO THE IDENTIFICATION OF ADRENERGIC AND CHOLINERGIC NERVES AND NERVE ENDINGS IN ITS INTRINSIC MUSCLES. Am J Anat. 1964 Mar;114:173–205. doi: 10.1002/aja.1001140202. [DOI] [PubMed] [Google Scholar]
- ROBERTSON J. D., BODENHEIMER T. S., STAGE D. E. THE ULTRASTRUCTURE OF MAUTHNER CELL SYNAPSES AND NODES IN GOLDFISH BRAINS. J Cell Biol. 1963 Oct;19:159–199. doi: 10.1083/jcb.19.1.159. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ROBERTSON J. D. Ultrastructure of excitable membranes and the crayfish median-giant synapse. Ann N Y Acad Sci. 1961 Sep 6;94:339–389. doi: 10.1111/j.1749-6632.1961.tb35552.x. [DOI] [PubMed] [Google Scholar]
- ROSENBLUTH J., PALAY S. L. The fine structure of nerve cell bodies and their myelin sheaths in the eighth nerve ganglion of the goldfish. J Biophys Biochem Cytol. 1961 Apr;9:853–877. doi: 10.1083/jcb.9.4.853. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ROSENBLUTH J. The fine structure of acoustic ganglia in the rat. J Cell Biol. 1962 Feb;12:329–359. doi: 10.1083/jcb.12.2.329. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rosenbluth J. Ultrastructural organization of obliquely striated muscle fibers in Ascaris lumbricoides. J Cell Biol. 1965 Jun;25(3):495–515. doi: 10.1083/jcb.25.3.495. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TASAKI I. New measurements of the capacity and the resistance of the myelin sheath and the nodal membrane of the isolated frog nerve fiber. Am J Physiol. 1955 Jun;181(3):639–650. doi: 10.1152/ajplegacy.1955.181.3.639. [DOI] [PubMed] [Google Scholar]
- WIENER J., SPIRO D., LOEWENSTEIN W. R. STUDIES ON AN EPITHELIAL (GLAND) CELL JUNCTION. II. SURFACE STRUCTURE. J Cell Biol. 1964 Sep;22:587–598. doi: 10.1083/jcb.22.3.587. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WOOD R. L. Intercellular attachment in the epithelium of Hydra as revealed by electron microscopy. J Biophys Biochem Cytol. 1959 Dec;6:343–352. doi: 10.1083/jcb.6.3.343. [DOI] [PMC free article] [PubMed] [Google Scholar]