Abstract
The natural spinning process in silkworms involves the conformation transition of the liquid silk protein present in the silk gland to make fiber. This conformation transition is influenced by different factors, and some studies suggested that changes in the metallic ion concentrations is one of them (Zhou et al. 2005). This study investigated the changes in the metallic ion compositions in the silk glands (before and during spinning) and cocoons of non-mulberry silkworm Antheraea assamensis helfer. Intact silk glands were dissected from mature 5th instar A. assamensis larvae. The glands were rinsed with deionized water and divided into five divisions: posterior silk gland (PSG), middle silk gland (MSG), anterior silk gland (ASG), posterior middle (PM) and anterior middle (AM) division of silk gland. Cocoon pieces and the gland parts were dried and digested in acid mixture to quantify the metallic contents in an atomic absorption spectrophotometer (Shimadzu, AA7000). We determined seven metals (Na, K, Mg, Ca, Cu, Zn, Fe) present in the different parts of the secretory pathway as well as in the fibers of A.assamensis. Our results suggested that the concentrations of Mg, Ca, Na, and K were more abundant in the gland than the Cu and Zn. Fe concentration was found comparatively less in amount in the gland. Amount of Ca found to be higher in the cocoons. The differences in the metallic ion concentrations in the gland parts before and during spinning suggested the possibility of their role in the formation of silk thread from luminal silk.
References
Helfer TW (1837) On the indigenous silkworm of India. Journal of the Asiatic Society of Bengal 6(1):38–47
Devi D, Sarma NS, Talukdar B, Chetri P, Baruah KC, Dass NN (2011) Study of the structure of degummed Antheraea assamensis (muga) silk fibre. J Text Inst 102(6):527–533
Gupta A, Mita K, Arunkumar KP, Nagaraju J (2015) Molecular architecture of silk fibroin of Indian golden silkmoth, Antheraea assama. Sci Rep 5:12706
Wang, X., Li, Y., Liu, Q., Chen, Q., Xia, Q., & Zhao, P. (2017). In vivo effects of metal ions on conformation and mechanical performance of silkworm silks. Biochimica et. Biophysica Acta (BBA)-General Subjects, 1861(3), 567–576
Knight DP, Vollrath F (2001) Changes in element composition along the spinning duct in a Nephila spider. Naturwissenschaften 88(4):179–182
Zhou L, Chen X, Shao Z, Huang Y, Knight DP (2005) Effect of metallic ions on silk formation in the mulberry silkworm, Bombyx mori. J Phys Chem B 109(35):16937–16945
Magoshi J, Magoshi Y, Nakamura S (1994) Silk polymers. American Chemical Society, Washington, DC
Tanaka T, Magoshi J, Magoshi Y, Inoue S, Kobayashi M, Tsuda H, Nakamura S (2001) Inorganic constitution of silk fibroin. Polym Prepr Am Chem Soc, Div Polym Chem 42:623
Zhou L, Chen X, Shao Z, Zhou P, Knight DP, Vollrath F (2003) Copper in the silk formation process of Bombyx mori silkworm. FEBS Lett 554(3):337–341
Ochi A, Hossain KS, Magoshi J, Nemoto N (2002) Rheology and dynamic light scattering of silk fibroin solution extracted from the middle division of Bombyx mori silkworm. Biomacromolecules 3(6):1187–1196
Laity PR, Baldwin E, Holland C (2018) Changes in silk feedstock rheology during cocoon construction: the role of calcium and potassium ions. Macromol Biosci 1800188
Freddi G, Gotoh Y, Mori T, Tsutsui I, Tsukada M (1994) Chemical structure and physical properties of Antheraea assama silk. J Appl Polym Sci 52(6):775–781
Zhou P, Xie X, Knight DP, Zong XH, Deng F, Yao WH (2004) Effects of pH and calcium ions on the conformational transitions in silk fibroin using 2D Raman correlation spectroscopy and 13C solid-state NMR. Biochemistry 43(35):11302–11311
Berridge MJ, Oschman JL (1972) Transporting epithelia. Academic Press, London
Harvey WR, Maddrell SH, Telfer WH, Wieczorek H (1998) H+ V-ATPases energize animal plasma membranes for secretion and absorption of ions and fluids. Am Zool 38(3):426–441
Liu Q, Wang X, Tan X, Xie X, Li Y, Zhao P, Xia Q (2018) A strategy for improving the mechanical properties of silk fiber by directly injection of ferric ions into silkworm. Mater Des 146:134–141
Yu HZ, Zhang SZ, Ma Y, Fei DQ, Li B, Yang LA et al (2017) Molecular characterization and functional analysis of a ferritin heavy chain subunit from the Eri-silkworm, Samia cynthia ricini. Int J Mol Sci 18(10):2126
Dutta A, Dandapat J, Mohanty N (2019) First report on transferrin in the silkworm, Antheraea mylitta, with a putative role in antioxidant defence: insights from proteomic analysis and immunodetection. Comp Biochem Physiol B: Biochem Mol Biol 233:23–34
You XL, Wang LL, Liu ZF, Wang L, Zhou ZY, Li Z (2017) Identification of Bombyx mori ferritin gene and analysis on its sequence features and expression patterns. Sci Seric 43:0402–0413
Acknowledgments
The authors sincerely acknowledge the financial support provided by the Department of Science and Technology, Govt. of India, as INSPIRE Fellowship to AG.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of Interest
The authors declare that they have no conflict of interest.
Additional information
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Goswami, A., Devi, D. Variations in the Metallic Ion Concentration in the Silk Gland and Cocoon of Silkworm Antheraea assamensis helfer. Biol Trace Elem Res 196, 285–289 (2020). https://doi.org/10.1007/s12011-019-01919-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12011-019-01919-9