Expression pattern of enzymes related to juvenile hormone metabolism in the silkworm, Bombyx mori L.

Abstract

The physiological balance of juvenile hormone (JH) in insects depends on its biosynthesis and degradation pathway. Three key enzymes namely, juvenile hormone esterase (JHE), juvenile hormone epoxide hydrolase (JHEH) and juvenile hormone diol kinase (JHDK) are required for degradation in insects. Our present results showed that JHE and JHEH exhibited expression in almost all the tissues. This indicated that JHE and JHEH might degrade JH simultaneously. In addition, the highest levels of JHDK were observed in the midgut, with trace level being found in the malpighian tubule and haemocytes. Since the midgut is a digestive organ and not a JH target, it was hypothesized that both JHE and JHEH hydrolyzed JH to JH diol (JHd) which was then transported to midgut and hydrolyzed further by JHDK, to be finally excreted out of the body. Also the expression studies on JH degradation enzymes in different tissues and stages indicated that the activities of the three enzymes are specific and coincident with the JH functions in silkworm, Bombyx mori L.

Research Article Preliminary analysis on the developmental transcriptomes of swallowtail butterfly Papilio polytes (Lepidoptera: Papilioidae)

“…Out study showed that the JHEH gene was obviously up-regulated in larvae (L) compared with papue (P), resulting in a relatively lower JH titre in larvae (plot A, Figure 6); the JHAMT gene was not shown to be up-regulated, whereas the JHEH shown to be down-regulated in adults (A) compared with larvae (L), resulting in a higher JH titre in adults (plot B, Figure 6). These results were congruent with those of previous studies in other insect groups (Yang et al, 2011;Wijesekera and Dauwalder, 2016). Comparison of the juvenile hormone (JH) signalling pathway genes between different developmental stages: A: larvae (L) and pupae (P); B: larvae (L) and adults (A).…”

Involvement of a putative allatostatin in regulation of juvenile hormone titer and the larval development in Leptinotarsa decemlineata (Say)

“…In B. mori, the transcript of JHE was coincident with the JH titer pattern in vivo (Hua-jun et al, 2011). Thus, higher level of JH in L. decemlineata larval hemolymph after 1-3 days' ingestion of dsLdAS-C may upregulate the JHE, JHEH and/or JHDK, which subsequently degrade JH rapidly in L. decemlineata, and lower the JH titer in hemolymph.…”

“…Larval weight (mg) 4 days after feeding 88.4 ± 4.3 a 86.3 ± 3.8 a 72.2 ± 4.1 b 69.5 ± 3.4 b Rate of the third instar 2 days after feeding 1.00 ± 0.00 a 1.00 ± 0.00 a 0.89 ± 0.04 a 0.93 ± 0.10 a Rate of the fourth instar 4 days after feeding 0.94 ± 0.12 a 0.87 ± 0.23 a 0.28 ± 0.14 b 0.46 ± 0.08 b Larval duration (days) 14.6 ± 0.3 a 15.0 ± 0.3 a 16.1 ± 0.4 b 15.8 ± 0.4 ab Survivorship 6 days after feeding 1.00 ± 0.00 a 0.95 ± 0.00 a 0.98 ± 0.03 a 1.00 ± 0.00 a Pupation rate 1.00 ± 0.00 a 0.95 ± 0.00 a 0.94 ± 0.04 a 0.90 ± 0.06 a Emergence rate 0.95 ± 0.00 a 0.90 ± 0.00 a 0.85 ± 0.05 a 0.90 ± 0.07 a Different lowercase letters in each line indicate significant difference at P value b 0.05. named JH esterase (JHE), JH epoxide hydrolase (JHEH) and JH diol kinase (JHDK) (Hua-jun et al, 2011). In B. mori, the transcript of JHE was coincident with the JH titer pattern in vivo (Hua-jun et al, 2011).…”

Characterization and Expression Profiles of Juvenile Hormone Epoxide Hydrolase From Lymantria dispar (Lepidoptera: Lymantridae) and RNA Interference by Ingestion

“…4 ). High transcription levels of jheh have been detected in the Malpighian tubules, fat bodies, midgut and epidermis of L. decemlineata ( Lü et al 2015 ) and B. mori ( Yang et al 2011 ). This indicates that JHEH might degrade JH in various tissues ( Lü et al 2015 ).…”