Sensitivities to juvenile hormone and ecdysteroid in the diapause larvae of Omphisa fuscidentalis based on the hemolymph trehalose dynamics index

Singtripop, Tippawan; Oda, Yasunori; Wanichacheewa, Somsak; Sakurai, Shunsuke

doi:10.1016/s0022-1910(02)00104-x

Cited by 60 publications

(24 citation statements)

References 19 publications

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“…reach values between 40 and 50 mM (Singtripop et al, 2002). Although in R. prolixus the concentration of trehalose in the hemolymph was much lower than in non-hematophagous species, it is the predominant hemolymph carbohydrate (Figs.…”

Section: Discussionmentioning

confidence: 99%

Synthesis and mobilization of glycogen and trehalose in adult male Rhodnius prolixus

Mariano

Santos

Gonzalez

et al. 2009

Arch Insect Biochem Physiol

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The vector of Chagas' disease, Rhodnius prolixus, feeds exclusively on blood. The blood meals are slowly digested, and these insects wait some weeks before the next meal. During the life of an insect, energy-requiring processes such as moulting, adult gonadal and reproductive growth, vitellogenesis, muscular activity, and fasting, lead to increased metabolism. Carbohydrates are a major source of energy and their mobilization is important. We determined the amounts of glycogen, trehalose, and glucose present in the fat body and/or hemolymph of adult males of R. prolixus and recorded the processes of accumulation and mobilization of these carbohydrates. We also tested our hypothesis that these processes are under endocrine control. The amount of glycogen in the fat body progressively increased until the fourth day after feeding (from 9.3+/-2.2 to 77. 3+/-7.5 microg/fat body), then declined to values around 36.3+/-4.9 microg/fat body on the fifteenth day after the blood meal. Glycogen synthesis was eliminated in decapitated insects and head-transplanted insects synthesized glycogen. The amount of trehalose in the fat body increased until the sixth day after feeding (from 16. 6+/-1.7 to 40. 6+/-5.3 nmol/fat body), decreased abruptly, and stabilized between days 7 and 15 at values ranging around 15-19 nmol/fat body. Decapitated insects did not synthesize trehalose after feeding, and this effect was reversed in head-transplanted insects. The concentration of trehalose in the hemolymph increased after the blood meal until the third day (from 0.07+/-0.01 to 0.75+/-0.05 mM) and at the fourth day it decreased until the ninth day (0.21+/-0.01 mM), when it increased again until the fourteenth day (0.79+/-0.06 mM) after the blood meal, and then declined again. In decapitated insects, trehalose concentrations did not increase soon after the blood meal and at the third day it was very low, but on the fourteenth day it was close to the control values. The concentration of glucose in the hemolymph of untreated insects remained low and constant (0.18+/-0.01 mM) during the 15 days after feeding, but in decapitated insects it progressively increased until the fifteenth day (2.00+/-0.10 mM). We recorded the highest trehalase activity in midgut, which was maximal at the eighth day after feeding (2,830+/-320 nmol of glucose/organ/h). We infer that in Rhodnius prolixus, the metabolism of glycogen, glucose, and trehalose are controlled by factors from the brain, according to physiological demands at different days after the blood meal.

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Section: Discussionmentioning

confidence: 99%

Synthesis and mobilization of glycogen and trehalose in adult male Rhodnius prolixus

Mariano

Santos

Gonzalez

et al. 2009

Arch Insect Biochem Physiol

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“…The stock solution was diluted with acetone, and a 5-ml aliquot was applied topically to the dorsal surface of individual larvae (Singtripop et al, 2002). The 20E (Sigma, St. Louis, MO, USA) was dissolved in distilled water at a concentration of 1 mg/ml and stored at À20 1C until use.…”

Section: Hormonesmentioning

confidence: 99%

“…The trehalose concentration, however, decreases before pupation, suggesting that it is dynamically controlled during postembryonic development. The trehalose concentration is extremely high in lepidopteran larvae during diapause, suggesting that hemolymph trehalose is involved in survival in the face of environmental extremes (Goto et al, 1993;Li et al, 2002;Singtripop et al, 2002). Cellular damage resulting from extreme temperatures, osmotic/ oxidative stress, toxic chemical exposure, desiccation, hydrostatic pressure changes, and nutrient starvation has been shown to affect the production and utilization of trehalose (Crowe et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

“…The trehalose concentration in the hemolymph ranges between 40 and 50 mM during diapause and then decreases to an almost undetectable level after pupation. The termination of larval diapause is associated with a rise in the ecdysteroid concentration in the hemolymph and a decline in the trehalose concentration (Singtripop et al, 2002). Exogenous 20-hydroxyecdysone (20E) has been shown to lower the hemolymph trehalose concentration in Bombyx mori (Oda et al, 2000) and O. fuscidentalis (Singtripop et al, 2002), indicating that 20E elevates trehalase activity at the termination of larval diapause.…”

Section: Introductionmentioning

confidence: 99%

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Regulation of soluble and membrane-bound trehalase activity and expression of the enzyme in the larval midgut of the bamboo borer Omphisa fuscidentalis

Tatun

Singtripop

Tungjitwitayakul

et al. 2008

Insect Biochemistry and Molecular Biology

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“…Trehalose concentration in the hemolymph is regulated homeostatically in the short term (minutes and hours; Oda et al, 2000;Blatt and Roces, 2001) and long term (days and months) as seen in insect growth (Friedman, 1978;Ogiso and Takahashi, 1984;Oda et al, 1997) and diapause (Goto et al, 1993;Singtripop et al, 2002). Long-term regulation has been studied from the perspective of hormonal control of trehalase activities (Steele and Paul, 1985), i.e., hyperglycemic hormone for homeostatic regulation (Gäde et al, 1997) and 20-hydroxyecdysone (Yaginuma and Happ, 1989;Oda et al, 2000;Tatun et al, 2008a) for regulation during larval growth and larval-pupal transformation.…”

Section: Introductionmentioning

confidence: 99%

Possible involvement of proteinaceous and non-proteinaceous trehalase inhibitors in the regulation of hemolymph trehalose concentration in Bombyx mori

Tatun

Singtripop

Osugi

et al. 2009

Appl. Entomol. Zool.

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The midgut of the silkworm Bombyx mori contains two types of trehalase: soluble and membrane-bound. The trehalose concentration in larval hemolymph remains substantially high through the feeding period of the last (fifth) larval instar, despite appreciable trehalase activity through this period. We found that B. mori larval hemolymph contains two types of trehalase inhibitor, a proteinaceous inhibitor (inhibitor-P) and an inhibitor that is extractable with methanol and ethanol (inhibitor-M). Both inhibit the two types of trehalase, but with different sensitivities. Inhibitor-P inhibited soluble trehalase (ST) more effectively than membrane-bound trehalase (MT), while inhibitor-M inhibited MT slightly more than ST. The inhibitory activity of inhibitor-M was high during the early to middle feeding period, followed by a sudden decrease during the late feeding period. Inhibitor-P activity increased throughout the feeding period, and markedly decreased 2 days after gut purge. Thus, the two inhibitors exhibited stage-specific changes in the hemolymph, indicating coordinated inhibitory activity. Therefore, trehalose concentration regulation in the hemolymph appears to be complex, consisting of at least two inhibitors and two types of trehalase.

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Sensitivities to juvenile hormone and ecdysteroid in the diapause larvae of Omphisa fuscidentalis based on the hemolymph trehalose dynamics index

Cited by 60 publications

References 19 publications

Synthesis and mobilization of glycogen and trehalose in adult male Rhodnius prolixus

Synthesis and mobilization of glycogen and trehalose in adult male Rhodnius prolixus

Regulation of soluble and membrane-bound trehalase activity and expression of the enzyme in the larval midgut of the bamboo borer Omphisa fuscidentalis

Possible involvement of proteinaceous and non-proteinaceous trehalase inhibitors in the regulation of hemolymph trehalose concentration in Bombyx mori

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