Central Sericultural Research & Training Institute, Mysore ?570008, Karnataka, India.
A bivoltine silkworm hybrid, KA x NB4D2 was treated with the juvenoid R394 (Ethyl-9 cyclohexyl-3,7-dimethyl-2,4-nonadienoate) at a dose of 0.039 nl/larva at 24, 48, 72 and 96 h of 5th instar for silk yield improvement. Treatment specific significant increase was observed in the cocoon and shell weight with no such marked variation in the shell percentage. Notable changes were also seen in traits such as larval duration, larval weight and silk gland weight in the treated silkworm. Total protein, total carbohydrate and total lipid were analyzed in the posterior silk gland (PSG), haemolymph and fat body of fully grown larvae. The result indicated that the content of these primary metabolites varied significantly in the selected tissues depending on the time of juvenoid application. The highest content of protein in the haemolymph and silk gland was in the larvae treated at 72 h whereas the fat body protein content was lowest in the same group. The total carbohydrate was recorded lowest in the 72 h treated larvae as against the highest in the control both in haemolymph and fat body with no significant change in PSG. The total lipid content did not show any notable variation in the concentration on juvenoid administration except in the silk gland treated up to 72 h which showed a decline. The result indicates that the juvenoid induces tissue specific responses in terms of turnover in primary metabolites.
Akai, H., Kimura, K., Kiuchi, M. and Shibukawa, A. (1985) Increase of silk production by repeated treatments with a juvenile hormone analogue. J. Seric. Sci. Jpn. 54, 297-299.
Carrol, N.V., Longley, R.W. and Rose, J. H. (1956) Glycogen determination in the liver and muscle by use of anthrone reagent. J. Biol. Chem. 220, 583-593.
Chen, P.S. (1985) Amino acid and protein metabolism. Comprehensive Insect Physiology, Biochemistry and Pharmcoclogy. Vol. 10. (eds. Kertkut, G. A. and Gilbert L. I), pp. 177-218. Pergamon Press. Oxford.
Chowdhary, S.K., Raju, P.S. and Ogra, R. K. (1990) Effect of JH analogues on silkworm, Bombyx mori L., growth and development of silk gland. Sericologia 30, 155-165.
Cymborowski, B. and Stolarz, G. (1979) The role of juvenile hormone during larval pupal transformation of Spodoptera littoralis: Switchover in the sensitivity of the prothoracic gland to juvenile hormone. J. Insect Physiol., 25, 939-942
Folch, J.M., Lees, P. and Stane-Stanely, G.H. (1957) A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem. 226, 497-509.
Gilbert, L.I. (1967) Lipid metabolism and function in insects. Advances in Insect Physiology. Vol. 4. (eds. Beament, J. W. L., Treherne, J. E. and Wigglesworth, W. B.) pp. 69-211. Academic Press, New York.
Harper, H.A., Rodwell, V.W. and Mayes, P.A. (1993) Review of physiological chemistry. Lange Medical Publication. Los Altos, California, pp. 131-182.
Hugar, I.I. and Kaliwal, B.B. (1998) Effect of Benzyl-6-aminopurine and indole –3-acetic acid on the biochemical changes in the fat body and haemolymph of the bivoltine silkworm, Bombyx mori L. Bull. Sericult. Res. 9, 63-67.
Krishnaswami, S. (1978) New technology of silkworm rearing. Bulletin. Central Sericultural Research and Training Institute, Mysore India, No.2. pp. 1-24
Lowry, O.H., Rosebrough, N.J., Farr, A.L. and Randal, R.J. (1951) Protein measureement with folin- phenol reagent. J. Biol. Chem. 193, 265-275.
Muroga, A., Nakajima, M., Aomori, S., Ozawa, Y. and Nihmura M. (1975) Utilization of the synthetic juvenile hormone analog to the silkworm rearing on mulberry leaves. J. Sericult. Sci. Jpn. 44, 267-273.
Nair, K.S., Vijayan, V.A., Nair, J.S., Trivedy, K. (1999) Juvenilomimic compounds for enhanced productivity in silkworm, Bombyx mori L. – A screening. Indian J. Seric. 38, 119- 124.
Nair, K.S., Vijayan, V.A., Nair, J.S., Trivedy, K. and Chinya, P.K. (2002) Hormetic influence on silkworm, Bombyx mori L of a phytojuvenoid, ω-formyl longifolene oxime propargyl ether. Insect Sci. Applic. 22, 145- 150.
Nair, K.S., Vijayan, V.A., Trivedy, K. and Nair, J.S (2001) Improvement in the Commercial Traits of Silkworm, Bombyx mori L. by Administration of a Juvenoid, R394. Int. J. Industrial Entomol. 3, 169-175.
Nakayama, S., Fuji, S. and Yamamoto, R. (1990) Changes in activities of glycosidases in the haemolymph of the silkworm, Bombyx mori, during larval development. J. Seric. Sci. Jpn. 59, 443-451.
Riddiford, L.M. and Truman, J.W. (1978) Biochemistry of insect hormones and insect growth regulators. Biochemistry of Insects. (ed. Rockstein, M.) pp. 308-357. Academic Press, New York.
Sehnal, F. and Akai, H. (1990) Insect silk glands: Their types, development and function and effects of environmental factors and morphogenetic hormones on them. Int. J. Insect Morphol. Embryol. 19, 79-132
Thomas, K.K. and Nation, J.L. (1966) RNA, protein and uric acid content of body tissues of Periplaneta americana L. as influence by corpora allata during ovarian devlopment. Biol. Bull. 130, 442-449.
Tojo, S., Kiguchi, K. and Kimura, S. (1981) Hormonal control of storage protein synthesis, and uptake by the fat body, in the silkworm, Bombyx mori. J. Insect Physiol., 27, 491-497.