Skip to main content
PMC home page
The Journal of Cell Biology logoLink to The Journal of Cell Biology
. 1968 Sep 1;38(3):574–588. doi: 10.1083/jcb.38.3.574

STUDIES ON THE POSTERIOR SILK GLAND OF THE SILKWORM, BOMBYX MORI

I. Growth of Posterior Silk Gland Cells and Biosynthesis of Fibroin During the Fifth Larval Instar

Yutaka Tashiro 1, Takashi Morimoto 1, Shiro Matsuura 1, Sunao Nagata 1
PMCID: PMC2108375  PMID: 5664226

Abstract

Growth of the posterior silk gland and biosynthesis of fibroin during the fifth larval instar of the silkworm, Bombyx mori, have been studied. In accordance with the exponential increase in the wet weight of the gland, the amounts of DNA, RNA, protein, and lipids per animal increased rapidly in the early stage of the fifth instar (0–96 hr). Biosynthesis of fibroin, on the contrary, mainly proceeds in the later stage of the fifth instar (120–192 hr). Electron microscopical observations have shown that, in the very early stage (0–12 hr), a number of free ribosomes exist in the cytoplasm. Rough endoplasmic reticulum (ER) with closely spaced cisternae was also observed. Then rough ER starts to proliferate rapidly, and at the same time lamellar ER is rapidly or gradually transformed into vesicular or tubular forms. In the later stage of the fifth instar (120–192 hr), the cytoplasm is mostly filled with tubular or vesicular ER. Golgi vacuoles, free vacuoles (fibroin globules), and mitochondria are also observed. It is concluded that in the early stage of the fifth instar the cellular structures necessary for the biosynthesis of fibroin are rapidly formed, while in the later stage the biosynthesis of fibroin proceeds at a maximum rate and utilizes these structures.

Full Text

The Full Text of this article is available as a PDF (1.6 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Allen R. J. The estimation of phosphorus. Biochem J. 1940 Jun;34(6):858–865. doi: 10.1042/bj0340858. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bartels P. G., Weier T. E. Particle arrangements in proplastids of Triticum vulgare L. seedlings. J Cell Biol. 1967 May;33(2):243–253. doi: 10.1083/jcb.33.2.243. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. DENUCE J. M. Etude quantitative de l'acide ribonucléique dans les glandes séricigènes chez Bombyx mori L. Biochim Biophys Acta. 1952 Jan;8(1):111–111. doi: 10.1016/0006-3002(52)90017-6. [DOI] [PubMed] [Google Scholar]
  4. Dallner G., Siekevitz P., Palade G. E. Biogenesis of endoplasmic reticulum membranes. I. Structural and chemical differentiation in developing rat hepatocyte. J Cell Biol. 1966 Jul;30(1):73–96. doi: 10.1083/jcb.30.1.73. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. FUKUDA T., FLORKIN M. Contributions to silkworm biochemistry. VII. Ordered progression on fibroinogen in the reservoir of the silkgland during the 5th instar. Arch Int Physiol Biochim. 1959 Apr;67(2):214–221. doi: 10.3109/13813455909074429. [DOI] [PubMed] [Google Scholar]
  6. Farquhar M. G., Palade G. E. Cell junctions in amphibian skin. J Cell Biol. 1965 Jul;26(1):263–291. doi: 10.1083/jcb.26.1.263. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. HERMAN L., FITZGERALD P. J. Restitution of pancreatic acinar cells following ethionine. J Cell Biol. 1962 Feb;12:297–312. doi: 10.1083/jcb.12.2.297. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. HOSODA J., SHIGEMATSU H., TAKESHITA H. O., MIZUNO S., TAKAHASHI H., MARUO B. RIBONUCLEIC ACID METABOLISM IN THE POSTERIOR SILKGLAND OF SILKWORM, BOMBYX MORI, DURING THE FIFTH INSTAR. Biochim Biophys Acta. 1963 Aug 20;72:544–554. [PubMed] [Google Scholar]
  9. I'AKEYAMA S., ITO H., MIURA Y. Fibroin synthesis and ribonucleic acid metabolism in the silk gland. Biochim Biophys Acta. 1958 Nov;30(2):233–243. doi: 10.1016/0006-3002(58)90045-3. [DOI] [PubMed] [Google Scholar]
  10. Jamieson J. D., Palade G. E. Role of the Golgi complex in the intracellular transport of secretory proteins. Proc Natl Acad Sci U S A. 1966 Feb;55(2):424–431. doi: 10.1073/pnas.55.2.424. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. KESSEL R. G. ELECTRON MICROSCOPE STUDIES ON OOCYTES AND ECHINODERM, THYONE BRIAREUS, WITH SPECIAL REFERENCE TO THE ORIGIN AND STRUCTURE OF THE ANNULATE LAMELLAE. J Ultrastruct Res. 1964 Jun;10:498–514. doi: 10.1016/s0022-5320(64)80025-3. [DOI] [PubMed] [Google Scholar]
  12. LOCKE M. Pore canals and related structures in insect cuticle. J Biophys Biochem Cytol. 1961 Aug;10:589–618. doi: 10.1083/jcb.10.4.589. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. LUFT J. H. Permanganate; a new fixative for electron microscopy. J Biophys Biochem Cytol. 1956 Nov 25;2(6):799–802. doi: 10.1083/jcb.2.6.799. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Miura Y., Itoh H., Sunaga K., Ogoshi S. Studies on the protein synthesis in silkglands. VI. RNA metabolism during fifth instar larvae. J Biochem. 1965 Sep;58(3):293–299. doi: 10.1093/oxfordjournals.jbchem.a128201. [DOI] [PubMed] [Google Scholar]
  15. Morimoto T., Matsuura S., Nagata S., Tashiro Y. Studies on the posterior silk gland of the silkworm, Bombyx mori. 3. Ultrastructural changes of posterior silk gland cells in the fourth larval instar. J Cell Biol. 1968 Sep;38(3):604–614. doi: 10.1083/jcb.38.3.604. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. PALADE G. E. Intracisternal granules in the exocrine cells of the pancreas. J Biophys Biochem Cytol. 1956 Jul 25;2(4):417–422. doi: 10.1083/jcb.2.4.417. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. 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]
  18. SIEKEVITZ P., PALADE G. E. A cytochemical study on the pancreas of the guinea pig. II. Functional variations in the enzymatic activity of microsomes. J Biophys Biochem Cytol. 1958 May 25;4(3):309–318. doi: 10.1083/jcb.4.3.309. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Shigematsu H., Takeshita H., Onodera S. Effect of actinomycin and mitomycin on fibroin synthesis in the posterior silkgland of Bombyx mori. J Biochem. 1965 Dec;58(6):604–606. doi: 10.1093/oxfordjournals.jbchem.a128250. [DOI] [PubMed] [Google Scholar]
  20. 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]
  21. WATSON M. L. The nuclear envelope; its structure and relation to cytoplasmic membranes. J Biophys Biochem Cytol. 1955 May 25;1(3):257–270. doi: 10.1083/jcb.1.3.257. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. WEISS J. M. The ergastoplasm; its fine structure and relation to protein synthesis as studied with the electron microscope in the pancreas of the Swiss albino mouse. J Exp Med. 1953 Dec;98(6):607–618. doi: 10.1084/jem.98.6.607. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. 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]

Articles from The Journal of Cell Biology are provided here courtesy of The Rockefeller University Press

RESOURCES