Effect of ultrasound on protein metabolism in the silkworm, &lt;i&gt;Bombyx mori&lt;/i&gt; (L.)

Mp Murali,Pc Sahitya,Sp Siva

doi:10.4314/ejst.v7i2.1

Abstract

The parameters of protein metabolism, such as the levels of soluble, structural and total proteins, free amino acids, and the activity levels of protease, aspartate and alanine aminotransferases and glutamate dehydrogenase were assayed in the hemolymph, silk-gland, muscle and fat-body on different days of the 5th instar larva of the silkworm, Bombyx mori, following exposure of the silkworm eggs to 1 MHz continuous wave of ultrasound at an intensity of 9W/cm2 for 2 minutes. Ultrasound was found to promote the accumulation of proteins, which include silk proteins as well, while retarding proteolysis and turnover of proteins towards the release of amino acids, keto-acids etc. Changes in the levels of these biochemical constituents are correlated with the events of histogenesis and histolysis associated with metamorphosis. It may be inferred that protein metabolism is stimulated by ultrasound, resulting in greater turnover of silk proteins, spinning activity and silk output.Key words: Ultrasound, Silkworm, Bombyx mori, Proteins, Amino Acids, Protease, Aminotransferases, Glutamate dehydrogenase.

Highlights

Insect metamorphosis is a dynamic biochemical activity. Chen (1971) highlighted the role of biochemical constituents in insect metamorphosis
The growth of silkworm during metamorphosis is accompanied by the increase in the body weight and accumulation of various biochemical constituents like proteins, amino acids and enzymes like proteases, aminotransferases and glutamate dehydrogenase (Pant and Jaiswal, 1981; Bannikov et al, 1982; Wangerli and Xuting-Sen, 1982; Bose et al, 1989; Siva Prasad and Murali Mohan, 1990)
Changes in biochemical parameters of protein metabolism such as proteins, free amino acids, and the activity levels of the enzymes protease, aspartate and alanine aminotransferases, and glutamate dehydrogenase were observed in the 5th instar larvae

Summary

Introduction

Insect metamorphosis is a dynamic biochemical activity. Chen (1971) highlighted the role of biochemical constituents in insect metamorphosis. A novel approach in silkworm research is the manipulation of biochemical machinery through exogenous modulators that could boost the silk production This included the administration of certain neurohumoral factors, vertebrate hormones and various other chemicals like cyclic AMP and prostaglandins, which could have a profound influence on the growth rate, larval life cycle and fecundity (Singh and Dutta, 1980; Bharathi and Govindappa, 1987; Thyagaraja et al, 1991; Bharathi, 1993). Significant positive impact of vertebrate thyroxine on silkworm biology, especially in improving the pre- and post-cocoon parameters is well documented (Bharathi et al, 1986; Krishnamurthy et al, 1987; Chaudhuri and Medda, 1992). The dietary administration of vertebrate sex hormones like ethynyl estradiol (EE) and norethindrone (NE) to the silkworm increased the larval weight, cocoon and shell weights, female pupal and adult weights, but the larval, pupal periods and the egg-hatchability were significantly reduced (Saha and Khan,1977)

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Conclusion