• Journal of Sericultural and Entomological Science
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• v.35 no.1
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• pp.28-35
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• 1993

Treatment of juvenile hormone analogue(JHA) at the 5th instar larvae prolonged the duration of adult development one to one and half days as well as the elongation of feeding time with the increasing of larval body weight. Morphological observation and protein analysis in hemolymphs, integuements, alimentary canals, fat bodies and ovaries also revealed that the development of these tissues and organs for adultation are affected by the JHA treatment.

• Journal of Sericultural and Entomological Science
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• v.28 no.1
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• pp.37-42
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• 1986

The experiment was carried out to investigate the effects of juvenile hormone analogue on changes of protein and amino acids in haemolymph of silkworm larva. Juvenile hormone analogue was topically administered to larvae at dose of 1$\mu\textrm{g}$ 10$\mu\textrm{g}$ per gm of body weight at 60hr. of the 5th instar. The results obtained were as follows ; 1. Larval duration of the fifth instar was extended about 1 day by JHA-1 and 4 days by JHA-10 as compared with the control. 2. Cocoon weight and cocoon layer weight by topical application of JHA were heavier than those of the control, but cocoon layer ratio was decreased in JHA-10 to the exclusion of JHA-1. 3. The concentration of haemolymph protein during the fifth instar was increased remarkably by the JHA application. 4. The total content of amino acids in haemolymph proteins of JHA-10 approximately doubled that of the control, with the conspicuous increase of glycine and arginine level.

• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.114-120
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• 1995

The effect of juvenile hormone analogue(JHA, Manina) on larval feeding duration, pupation ratio, cocoon weight, and cocoon shell weight in the present commercial parent and hybrid silkworm stocks were investigated. Topical applications of JHA on parent silkworm stocks were to prolong larval duration, but results of response on those stocks were not consistent. Especially the JHA on Jam 121, Jam 123 and Jam 138 did not play a role in larval duration, whereas that on Jam 114 was most effective in prolongation more than two days, compared with the controls. subsequent prolongation of feeding duration resulted in increase of cocoon weight and cocoon shell weight of most parent silkworm stocks, while Jam 114 showed decrease in cocoon weight and cocoon shell weight in spite of prolonged feeding duration of two days. Unlike the parent silkworm stocks, durations of feeding period in all hybrid silkworm stocks were prolonged about one day. Treatments of JHA on the hybrid stocks gave rise to increase of cocoon weight and cocoon shell weight, and especially were most effective in Sasung-jam, Eunbaek-jam and Samgwang-jam. Although treatments of JHA seemed to have no harmful effect on physiology of parent silkworm stocks as well as that of hybrid stocks, the JHA retarded pupation ratio of some parent silkworm stocks such as Jam 122, 131, 135 and 138 by about 10%.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.137-141
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• 2002

An experimental study was undertaken to quantify the effects of insect hormones on the replication of nucleopolyhedrovirus (NPV). The results demonstrated that TCID/ sub 50/ at 72 h post-infection (hpi) rose systematically from 0.55$\times$10$^{8}$ /m1, for untreated cells, up to 1.67$\times$10$^{8}$ / ml at 3$\mu$g/ml, then dropped down to 1.45$\times$10$^{8}$ /m1 at 4 $\mu$g/ml, by adding ecdysone to the culture medium for Bm-N cells infected with a wild-type Bambyx mori. nucleopolyhedrovirus (BmNPV). The optimum enhancement of about 3 times on budded virus (BV) titer at 72 hpi was given at 3 $\mu$g/ml of ecdysone. While the polyhedra number had no obvious variation within the range of concentrations from 0 to 4 $\mu$g/ml. By addition of juvenile hormone analogue (JHA) into the media with this concentration range, the BmNPV TCID/ sub 50/ and polyhedra number at 72 hpi did not show significant changes. Also, the addition of either 3 $\mu$g/ml of ecdysone or 3 $\mu$g/ml of JHA to the culture media did not appear to affect the TCID/ sub 50/ and polyhedra number significantly in infected Sf-21 cells with the autographa californica nucleopolyhedrovirus (AcMNPV).

• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.1
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• pp.129-135
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• 2011

Cathepsins are well-characterized proteases that are ubiquitously expressed in lysosomes. Previous work revealed that $Bombyx$ $mori$ cathepsins B and D are expressed in the fat body and undergo decomposition during larval-pupal metamorphosis. Quantitative RT-PCR was performed to detect cathepsin gene expression at the transcription level when challenged by $B.$ $mori$ nuclear polyhedrosis virus (BmNPV), temperature and hormones (20-hydroxyecdysone (20E) and juvenile hormone analogue (JHA)). mRNAs encoding cathepsins B and D were significantly enhanced after the larvae were infected with BmNPV, and the peak of the induction appeared at 1 day before spinning. This attenuated the inducing effect on cathepsin expression caused by infection. Temperature shock induced cathepsin expression at the later stage of the $5^{th}$ instar, and transcription levels varied with development stage and temperature. Cathepsin B and D mRNA expression in the fat body were significantly induced by JHA at the day before spinning, and with 20E, the expression reached a peak at the last day of the $5^{th}$ instar. Cathepsin B and D mRNA expression exhibited detectable changes post-treatment, without significant differences between or among the hormone concentrations.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.137-141
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• 2005

Though many insecticides are commercially available, development of resistance, pest resurgence and effects on non-target organisms led to the search for alternate insect pest management (IPM) strategy based on larval growth and reproductive fitness. Reproductive potential of insects depends on its acquiring of vitellogenic competence which is under hormonal control. Exogenous application of analogues of JR (JHAs) and ecdysterone could derail normal development and reproduction in insects by manipulating an array of physiological processes. In the rice pest, brown planthopper, Nilaparvata lugens, JHA, hydroprene induced metathetely from the fifth (final) instar nymphs in an age-dependent manner. Day 0 of the final instar showed highest sensitivity to induce this abnormal development. Adults emerged from treated day 3 nymphs looked normal. Both the morphotypes were reproductively incompetent and showed partial to complete sterility. Pre-adult exposure of the ovarian tissue to hydroprene suppressed mitotic division of germinal cells and induced abnormalities in the later s1ages of growth and differentiation of ovary in N. lugens. More over the nymphal exposure to hydroprene inhibited patency changes of follicular epithelium and affected competence of the follicles for yolk sequestration. In the absence of ovarian growth and oocyte differentiation, germarium found disintegrated, trophic core regressed and terminal oocytes resorbed. Hydroprene exposure to newly ecdysed brachypterous females did not affect ovarian development and egg production. Proper larval-adult transition appeared as a. prerequisite for vitellogenic competence in N. lugens for which the ovarian tissues must be exposed to ecdysterone in the internal milieu devoid of JH.