Abstract
Electron microscope preparations were made of specimens of Actinosphaerium nucleofilum fixed in glutaraldehyde before, during, and after exposure to high pressures (4,000 to 8,000 psi). A study of this material showed that, although other organelles were relatively stable, the microtubular elements of the axopodia and cytosome became unstable under pressure. Their rapid disintegration under pressure was correlated with beading and retraction of the axopodia. Moreover, after the release of pressure, microtubules reappeared as soon as, or sooner than the reextension of the axopodia. The rate of disintegration increased as the pressure was raised. At 4,000 psi, few if any tubules remained after 10 min, whereas at 6,000 and 8,000 psi the disintegration was much more rapid. Some adaptational reorganization of the microtubules and axopodia occurred while relatively low pressures were maintained. This was accompanied by an actual elongation of the axopodia in specimens maintained for 20 min at 4,000 psi, but was confined to knoblike axopodial remnants in animals kept at 6,000 psi. No regeneration of tubules or axopodia occurred at 8,000 psi. The presence of fibers and a finely fibrillar material in pressurized animals suggests that these may be derivatives of microtubular disintegration. This evidence, though purely morphological, is consistent with the hypothesis that microtubules play an important role not only in maintaining the formstability of the axopodia, but also in the active process by which the axopodia reextend themselves after retraction.
Full Text
The Full Text of this article is available as a PDF (2.0 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- ASTERITA H., MARSLAND D. The pellicle as a factor in the stabilization of cellular form and integrity: effects of externally applied enzymes on the resistance of Blepharisma and Paramecium to pressure-induced cytolysis. J Cell Comp Physiol. 1961 Aug;58:49–61. doi: 10.1002/jcp.1030580107. [DOI] [PubMed] [Google Scholar]
- BURGOS M. H., FAWCETT D. W. An electron microscope study of spermatid differentiation in the toad, Bufo arenarum Hensel. J Biophys Biochem Cytol. 1956 May 25;2(3):223–240. doi: 10.1083/jcb.2.3.223. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BYERS B., PORTER K. R. ORIENTED MICROTUBULES IN ELONGATING CELLS OF THE DEVELOPING LENS RUDIMENT AFTER INDUCTION. Proc Natl Acad Sci U S A. 1964 Oct;52:1091–1099. doi: 10.1073/pnas.52.4.1091. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Byrne J., Marsland D. Pressure-temperature effects on the form-stability and movements of Euglena gracilis var. Z. J Cell Physiol. 1965 Apr;65(2):277–284. doi: 10.1002/jcp.1030650216. [DOI] [PubMed] [Google Scholar]
- HARRIS P. Some structural and functional aspects of the mitotic apparatus in sea urchin embryos. J Cell Biol. 1962 Sep;14:475–487. doi: 10.1083/jcb.14.3.475. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KANE R. E. The mitotic apparatus. Fine structure of the isolated unit. J Cell Biol. 1962 Nov;15:279–287. doi: 10.1083/jcb.15.2.279. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KRISHAN A., BUCK R. C. STRUCTURE OF THE MITOTIC SPINDLE IN L STRAIN FIBROBLASTS. J Cell Biol. 1965 Mar;24:433–444. doi: 10.1083/jcb.24.3.433. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LANDAU J. V., PEABODY R. A. Endogenous adenosine triphosphate levels in human amnion cells during application of high hydrostatic pressure. Exp Cell Res. 1963 Jan;29:54–60. doi: 10.1016/0014-4827(63)90357-4. [DOI] [PubMed] [Google Scholar]
- LANDAU J. V., THIBODEAU L. The micromorphology of Amoeba proteus during pressure-induced changes in the sol-gel cycle. Exp Cell Res. 1962 Sep;27:591–594. doi: 10.1016/0014-4827(62)90027-7. [DOI] [PubMed] [Google Scholar]
- LUFT J. H. Improvements in epoxy resin embedding methods. J Biophys Biochem Cytol. 1961 Feb;9:409–414. doi: 10.1083/jcb.9.2.409. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MARSHALL J. M., NACHMIAS V. T. CELL SURFACE AND PINOCYTOSIS. J Histochem Cytochem. 1965 Feb;13:92–104. doi: 10.1177/13.2.92. [DOI] [PubMed] [Google Scholar]
- MARSLAND D. The mechanisms of cell division; temperature-pressure experiments on the cleaving eggs of Arbacia punctulata. J Cell Physiol. 1950 Oct;36(2):205–227. doi: 10.1002/jcp.1030360207. [DOI] [PubMed] [Google Scholar]
- MARSLAND D., ZIMMERMAN A. M. STRUCTURAL STABILIZATION OF THE MITOTIC APPARATUS BY HEAVY WATER, IN THE CLEAVING EGGS OF ARBACIA PUNCTULATA; INCREASED RESISTANCE TO PRESSURE-INDUCED DISORGANIZATION. Exp Cell Res. 1965 May;38:306–313. doi: 10.1016/0014-4827(65)90406-4. [DOI] [PubMed] [Google Scholar]
- REYNOLDS E. S. The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J Cell Biol. 1963 Apr;17:208–212. doi: 10.1083/jcb.17.1.208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SLAUTTERBACK D. B. CYTOPLASMIC MICROTUBULES. I. HYDRA. J Cell Biol. 1963 Aug;18:367–388. doi: 10.1083/jcb.18.2.367. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tilney L. G., Porter K. R. Studies on microtubules in Heliozoa. I. The fine structure of Actinosphaerium nucleofilum (Barrett), with particular reference to the axial rod structure. Protoplasma. 1965;60(4):317–344. doi: 10.1007/BF01247886. [DOI] [PubMed] [Google Scholar]
- WATSON M. L. Staining of tissue sections for electron microscopy with heavy metals. J Biophys Biochem Cytol. 1958 Jul 25;4(4):475–478. doi: 10.1083/jcb.4.4.475. [DOI] [PMC free article] [PubMed] [Google Scholar]