3‐oxoecdysteroid 3β‐reductase in various organs of the European corn borer, <i>Ostrinia nubilalis</i> (Hubner)

Gelman, Dale B.; DeMilo, Albert B.; Thyagaraja, Belgaum S.; Kelly, Thomas J.; Masler, Edward P.; Bell, Robert A.; Bořkovec, Alexej B.

doi:10.1002/arch.940170204

Cited by 19 publications

(8 citation statements)

References 33 publications

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“…The lack of 3-epimerization in O. nubilalis was an unexpected finding, as such a reaction is widespread in lepidopteran larvae (Weirich and Bell, 1997;Lafont et al, 2005). Our result is, however, consistent with the absence of 3-epimers detection in metabolic studies performed with various organs of O. nubilalis larvae (Gelman et al, 1991).…”

Section: Diversity Of Detoxification Pathways Against Ingested Ecdystsupporting

confidence: 87%

Diversity of detoxification pathways of ingested ecdysteroids among phytophagous insects

Rharrabe

Alla²,

Maria

et al. 2007

Arch Insect Biochem Physiol

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The metabolic pathways of ingested ecdysteroids have been investigated in three insect species, the aphid Myzus persicae and two Lepidoptera, Plodia interpunctella and Ostrinia nubilalis. M. persicae produces mainly a 22-glucoside conjugate, whereas P. interpunctella eliminates a mixture of 20E and its 3-oxo and 3-epi derivatives, both in free form and as conjugates with various fatty acids. O. nubilalis only produces fatty acyl ester conjugates. These data point out the great diversity of detoxification mechanisms used by phytophagous insects in order to overcome the potential harmful effects of ecdysteroids present in their food.

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Section: Diversity Of Detoxification Pathways Against Ingested Ecdystsupporting

confidence: 87%

Diversity of detoxification pathways of ingested ecdysteroids among phytophagous insects

Rharrabe

Alla²,

Maria

et al. 2007

Arch Insect Biochem Physiol

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“…3B,C). The molecular mass (36 kDa) of the enzyme was of the same order as those estimated by gel-exclusion chromatography in Manducn (20-30 kDa; [3,351) and Ostrinia nubilalis (25-27 kDa; [36]), and by SDS/PAGE in B. mori (42 kDa; Kinetic analysis of the haemolyph 3-dehydroecdysone 3 8 reductase revealed that the enzyme exhibits maximal activity at low 3-dehydroecdysone substrate concentrations, with a drastic ~321).…”

Section: Discussionsupporting

confidence: 54%

“…If 3-dehydroecdysone is envisaged as a prohormone, and the 3-dehydroecdysone 3P-reductase as an enzyme converting 3-dehydroecdysone to the more active ecdysone, not only in the haemolymph, but also in various other organs, such as the fat body, salivary glands, suboesophageal gland, Malpighian tubules, hindgut, brain [36] and midgut [21,40,411, the argument for a possible role for the enzyme in ecdysteroid activation is a persuasive one. For example, if 3-dehydroecdysone is sequestered into tissues, to be activated at specific points during development by the 3-dehydroecdysone 3P-reductase, this may account for the numerous observations that isolated abdomens moult in the absence of prothoracic glands (for review see [5]; [42]).…”

Section: Discussionmentioning

confidence: 99%

Purification and Characterisation of Haemolymph 3‐Dehydroecdysone 3β‐Reductase in Relation to Ecdysteroid Biosynthesis in the Cotton Leafworm Spodoptera littoralis

Chen

Webb

Powls

et al. 1996

European Journal of Biochemistry

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The in vitro secretion of ecdysteroids from the prothoracic glands of last instar larvae of Spodoptera littorulis was detected and analysed by HPLC-RIA. The primary product was identified as 3-dehydroecdysone (= 82%), with lesser amounts of ecdysone (= 18%). Interconversion of ecdysone and 3-dehydroecdysone by prothoracic glands was not detectable.3-Dehydroecdysone 3P-reductase activity was demonstrated in the haemolymph. Ecdysone, the endproduct, was characterised by reverse-phase and adsorption HPLC, chemical transformation into ecdysone 2, 3-acetonide, and mass spectrometry. The conditions for optimal activity were determined. The enzyme requires NADPH or NADH as cofactor and K,,, values for NADPH and NADH were determined to be 0.94 pM and 22.8 pM, respectively. Investigation of the kinetic properties of the enzyme, using either NADPH or NADH as cofactor, revealed that it exhibits maximal activity at low 3-dehydroecdysone substrate concentrations, with a drastic inhibition of activity at higher concentrations (> 5 pM). The results suggest that the 3-dehydroecdysone 3P-reductase has a high-affinity (low K,) binding site for 3-dehydroecdysone substrate, together with a lower-affinity inhibition site.The 3P-reductase enzyme was purified to homogeneity using a combination of poly(ethy1ene glycol) 6000 precipitation and successive FPLC fractionation on Mono-Q, phenyl Superose (twice), and hydroxyapatite columns. The native enzyme was shown to be a monomer with molecular mass of 36 kDa by SDSPAGE and gel-filtration chromatography. Furthermore, the activity of the enzyme during the last larval instar was found to reach a peak prior to that of the haemolymph ecdysteroid titre, supporting a role for the enzyme in development.Keywords: 3-dehydroecdysone 3P-reductase; ecdysone ; prothoracic gland; Spodoptera littoralis.In immature stages of insects, the prothoracic glands are the primary source of ecdysteroid (moulting hormone), generally ecdysone (Scheme 1, I) in most species. However, recently it has been shown that in most lepidopteran species studied, the major product of the glands is 3-dehydroecdysone (Scheme 1, U), together with varying proportions of ecdysone [l, 21. After release from the prothoracic glands, the 3-dehydroecdysone is reduced to ecdysone by an NAD(P)H-linked 3-dehydroecdysteroid 3p-reductase in the haemolymph [2-41. The level of reductase activity in different insect species would appear to be related to the proportion of 3-dehydroecdysone secreted by the prothoracicThe exact details of ecdysteroid biosynthesis are not fully elucidated, although the early and late stages are the best understood [5-81. There is substantial evidence for the intermediacy of 2,22,25-trideoxyecdysone (5p-ketodiol ; Scheme 1, 111) in the biosynthesis of ecdysone [5,8, 91. This labelled substrate is effi-

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“…It seems unlikely, however, that such well developed structures as the larval SG would have evolved in the Culicidae if they had no physiological role to fulfill. In other insect species, larval salivary secretions have been associated with digestion (Verma and Baylan, 1972; Agarwal, 1976; Verma et al, 1977), immunity (Turillazzi et al,2004; Korayem et al,2004, Candido-Silva et al,2007; Liu, 2004), larval molting (Gelman et al, 1991; Zheng et al, 2003) and even social interaction (Cummings et al, 1999; Hunt, 1991). …”

Section: Introductionmentioning

confidence: 99%

The salivary transcriptome of Anopheles gambiae (Diptera: Culicidae) larvae: A microarray-based analysis

Neira

Ribeiro

Heyland

et al. 2009

Insect Biochemistry and Molecular Biology

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In spite of the many recent developments in the field of vector sialomics, the salivary glands of larval mosquitoes have been largely unexplored. We used whole-transcriptome microarray analysis to create a gene-expression profile of the salivary gland tissue of fourth-instar Anopheles gambiae larvae, and compare it to the gene-expression profile of a matching group of whole larvae. We identified a total of 221 probes with expression values that were (a) significantly enriched in the salivary glands, and (b) sufficiently annotated as to allow the prediction of the presence/absence of signal peptides in their corresponding gene products. Based on available annotation of the protein sequences associated with these probes, we propose that the main roles of larval salivary secretions include: (a) immune response, (b) mouthpart lubrication, (c) nutrient metabolism, and (d) xenobiotic detoxification. Other highlights of the study include the cloning of a transcript encoding a previously unknown salivary defensin (AgDef5), the confirmation of mucus secretion by the larval salivary glands, and the first report of salivary lipocalins in the Culicidae.

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3‐oxoecdysteroid 3β‐reductase in various organs of the European corn borer, Ostrinia nubilalis (Hubner)

Cited by 19 publications

References 33 publications

Diversity of detoxification pathways of ingested ecdysteroids among phytophagous insects

Diversity of detoxification pathways of ingested ecdysteroids among phytophagous insects

Purification and Characterisation of Haemolymph 3‐Dehydroecdysone 3β‐Reductase in Relation to Ecdysteroid Biosynthesis in the Cotton Leafworm Spodoptera littoralis

The salivary transcriptome of Anopheles gambiae (Diptera: Culicidae) larvae: A microarray-based analysis

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